Florida Water Resource Journal Jan 2014 by Florida Water Resources Journal

Editor’s Office and Advertiser Information:

Florida Water Resources Journal 1402 Emerald Lakes Drive Clermont, FL 34711 Phone: 352-241-6006 • Fax: 352-241-6007 Email: Editorial, editor@fwrj.com Display and Classified Advertising, ads@fwrj.com

Business Office: P.O. Box 745, Windermere, FL 34786-0745 Web: http://www.fwrj.com General Manager:

Michael Delaney

Editor:

Rick Harmon

Graphic Design Manager:

Patrick Delaney

Mailing Coordinator:

Buena Vista Publishing

Published by BUENA VISTA PUBLISHING for Florida Water Resources Journal, Inc. President: Patrick Lehman, P.E. (FSAWWA) Peace River/Manasota Regional Water Supply Authority Vice President: Howard Wegis, P.E. (FWEA) Lee County Utilities Treasurer: Rim Bishop (FWPCOA) Seacoast Utility Authority Secretary: Holly Hanson (At Large) ILEX Services Inc., Orlando

Moving? The Post Office will not forward your magazine. Do not count on getting the Journal unless you notify us directly of address changes by the 15th of the month preceding the month of issue. Please do not telephone address changes. Email changes to changes@fwrj.com, fax to 352-241-6007, or mail to Florida Water Resources Journal, 1402 Emerald Lakes Drive, Clermont, FL 34711

NEWS AND FEATURES 4 4 10 18 29 47 50 68

TECHNICAL ARTICLES 6 12 30 40 52 62

Training Questions FSAWWA: Donna Metherall – 407-957-8443 or fsawwa.donna@gmail.com FWPCOA: Shirley Reaves – 321-383-9690

20 23 49 53 61 67 68 71 78

For Other Information DEP Operator Certification: Ron McCulley – 850-245-7500 FSAWWA: Peggy Guingona – 407-957-8448 Florida Water Resources Conference: 888-328-8448 FWPCOA Operators Helping Operators: John Lang – 772-559-0722, e-mail – oho@fwpcoa.org FWEA: Karen Wallace, Executive Manager – 407-574-3318

Websites Florida Water Resources Journal: www.fwrj.com FWPCOA: www.fwpcoa.org FSAWWA: www.fsawwa.org FWEA: www.fwea.org and www.fweauc.org Florida Water Resources Conference: www.fwrc.org Throughout this issue trademark names are used. Rather than place a trademark symbol in every occurrence of a trademarked name, we state we are using the names only in an editorial fashion, and to the benefit of the trademark owner, with no intention of infringement of the trademark. None of the material in this publication necessarily reflects the opinions of the sponsoring organizations. All correspondence received is the property of the Florida Water Resources Journal and is subject to editing. Names are withheld in published letters only for extraordinary reasons. Authors agree to indemnify, defend and hold harmless the Florida Water Resources Journal Inc. (FWRJ), its officers, affiliates, directors, advisors, members, representatives, and agents from any and all losses, expenses, third-party claims, liability, damages and costs (including, but not limited to, attorneys’ fees) arising from authors’ infringement of any intellectual property, copyright or trademark, or other right of any person, as applicable under the laws of the State of Florida.

Reducing Operating Costs Through Treatment Optimization: Tampa’s Advanced Wastewater Treatment Plant Experience—Charlie Lynch, Rory Jones, Emilie Moore, Steve Tamburini, and John Toomey Starting Up an Underloaded Biological Nutrient Removal Process—Craig Fuller, Charles Nichols, Mark Addison, David Wilcox, and Dwayne Kreidler Removing One of the “I’s” from Infiltration and Inflow—Frederick Bloetscher, Dominic F. Orlando, and Ronnie Navarro Incorporation of High-Level Ultraviolet Disinfection to Meet Stringent Effluent Discharge Disinfection Byproducts Limits—Lynn Spivey, Sean Chaparro, Steve Schaefer, and William Harrington Separate or Combined Sidestream Treatment: That is the Question—Rod Reardon Getting More Out of Activated Sludge Plants by Using a BioMag Process—Derya Dursun and Jose Jimenez

EDUCATION AND TRAINING

Membership Questions FSAWWA: Casey Cumiskey – 407-957-8447 or fsawwa.casey@gmail.com FWEA: Karen Wallace, Executive Manager – 407-574-3318 FWPCOA: Darin Bishop – 561-840-0340

Here’s to 65 Years—and to You! Poteet Re-Elected as FWPCOA Chair Technology Spotlight 2014 FWPCOA Officers and Committee Chairs Taste Test to be Held at Florida Water Resources Conference 2013 FSAWWA Awards 2013-2014 FSAWWA Board of Governors Third Water Festival a Huge Success—Kevin M. Vickers

TREEO Center Training Florida Water Resources Conference Exhibitor Prospectus and Call for Papers CEU Challenge FWPCOA Training Calendar FSAWWA Training FWPCOA State Short School FSAWWA Legislative Day in Tallahassee PACP/MACP/LACP Training ISA Water/Wastewater and Automatic Controls Symposium

COLUMNS 20 22 29 59 60 70

FWEA Focus—Greg Chomic FWEA Chapter Corner—Patricia DiPiero FSAWWA Speaking Out—Carl R. Larrabee Jr. Certification Boulevard—Roy Pelletier Spotlight on Safety—Doug Prentiss Sr. C Factor—Jeff Poteet

DEPARTMENTS 72 75 78

Service Directories Classifieds Display Advertiser Index

Volume 66

ON THE COVER: The Okeechobee Utility Authority Cemetery Road Wastewater Treatment Plant. (photo: Jamie Gamiotea)

January 2014

Number 1

Florida Water Resources Journal, USPS 069-770, ISSN 0896-1794, is published monthly by Florida Water Resources Journal, Inc., 1402 Emerald Lakes Drive, Clermont, FL 34711, on behalf of the Florida Water & Pollution Control Operator’s Association, Inc.; Florida Section, American Water Works Association; and the Florida Water Environment Association. Members of all three associations receive the publication as a service of their association; $6 of membership dues support the Journal. Subscriptions are otherwise available within the U.S. for $24 per year. Periodicals postage paid at Clermont, FL and additional offices.

POSTMASTER: send address changes to Florida Water Resources Journal, 1402 Emerald Lakes Drive, Clermont, FL 34711

Florida Water Resources Journal • January 2014

Here's to 65 Years -and to You! The Florida Water Resources Journal is excited about celebrating its 65th anniversary of publication this year. What began in 1949 as The Overflow, a black-and-white, copied, and stapled newsletter sponsored by the Florida Water & Sewage Works Operators Association, is now the publication you see before you: a four-color, full-service magazine for Florida's ever-changing water and wastewater industry. It serves as the official publication for the Florida Water & Pollution Control Operators Association (FWPCOA), the Florida Section of the American Water Works Association (FSAWWA), and the Florida Water Environment Association (FWEA). The history of water in the last six decades mirrors the history of the state. Without an abundant supply of clean, safe water, Florida would not have had such tremendous population and economic growth. In 1949, the population of the state was 2.5 million people; it now stands at close to 20 million—an almost ten-fold increase! Without water, Florida wouldn't have become one of the top tourist destinations in the world, with more than 60 million visitors each year. The Kennedy Space Center, and the attendant aerospace and military industries, as well as Walt Disney World and many other entertainment complexes, couldn't function without this vital resource. And of course, water is essential for Florida's orange industry and every other agricultural crop. It's interesting to note that what also started in 1949 were the official Florida welcome centers that opened on major thoroughfares across the state to assist auto travelers with information about attractions and interesting destinations—and offer everyone a complimentary cup of orange juice. The Journal has been assisting water industry professionals for the same number of years with the information they need to ensure a continuous source of life-giving water, for now and the future.

With technical and feature articles; information on education and training; updates from the heads of the three organizations; columns on certification, safety, legal, contractor, and other issues; the latest news and product information; and a classified and service directory, we strive to keep you up-to-date on every pertinent water issue. As the state moves forward, so does the magazine. Beginning this year, look for several exciting new features (including a new magazine title logo): Guest Columnist –Water and wastewater-related company executives, from utilities, manufacturers, distributors, and consulting firms, will present their thoughts on the issues of the day. Reader Profile –Employees will be highlighted, discussing their jobs and the industry. Company Profile –A full-page article will highlight a particular company's history, projects, and services. The 65th anniversary celebration will continue as we delve into the history of the magazine with special articles published throughout the year. In August, we will dedicate an entire issue to the history of the Journal, as well as that of FWPCOA, FSAWWA, and FWEA. But it wouldn't be much of a celebration without you—the reader. You are the reason the magazine exists. You are responsible for the success of the Journal and for the achievements in the industry that have allowed your state to grow and thrive. And that is something to celebrate, too. Join us in honoring this great industry by submitting an article, photographs, or historical information, or a congratulatory or historical advertisement, and show support for your magazine. –Rick Harmon, Editor

Poteet Re-Elected as FWPCOA President Jeff Poteet was re-elected as president of the Florida Water & Pollution Control Association (FWPCOA) for 2014 by the organization’s board of officers at their November 2013 meeting. He served as the organization’s president in 2013. Poteet is general manager of the water and sewer department for the City of Marco Island. He began his career as a wastewater operator trainee in 1992, advancing to his current position in 2010. He is in charge of three drinking water facilities, two wastewater facilities, an aquifer storage and recovery system, a reuse distribution system, and the collection and distribution system for two separate drinking water and wastewater service areas. Poteet has served FWPCOA at both the regional and state level. At the regional level, Jeff has been active in setting up schools and

January 2014 • Florida Water Resources Journal

workshops since the late 1990s, and has held the posts of secretary/treasurer, vice chair, and chair. From 2003 to 2008, Jeff served on the state board of directors as the local region’s representative, in 2009 and 2010 as secretary/treasurer-elect, and in 2011 and 2012 as vice president. “I’m excited about serving as the FWPCOA president for another year, along with the rest of the slate of officers, who were also re-elected. I look forward to continuing to focus on opportunities to grow our membership, find ways to get our members more involved in the industry, and expand our training programs. I am truly honored to have been given this opportunity for a second term and I look forward to working with our sister associations and other water-related organizations in the coming year.”

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Reducing Operating Costs Through Treatment Optimization: Tampa’s Advanced Wastewater Treatment Plant Experience Charlie Lynch, Rory Jones, Emilie Moore, Steve Tamburini, and John Toomey he City of Tampa (City) owns and operates the Howard F. Curren Advanced Wastewater Treatment Plant (Plant). The original facility was constructed in the 1950s and provided primary treatment of the City’s wastewater prior to discharge to Tampa Bay. Various upgrade and expansion programs implemented by the City over the years have increased the capacity of the plant, provided higher levels of treatment, increased energy efficiency and enhanced cogeneration, improved residuals handling, and met other objectives. Currently, a combination of physical, chemical, and biological unit operations and processes are used to provide a high level of treatment. Treated effluent from the plant is discharged to Tampa Bay, used within the plant for process purposes and for irrigation, or provided to the City’s reclaimed water customers through a distribution network. The residuals handling sys-

tem at the plant receives sludge from the primary settling facilities and the excess solids from the biological treatment stages. The system includes volume reduction, stabilization, dewatering, and drying operations. Treated residuals from the heat drying system are hauled to a fertilizer company for further treatment and blending. Dewatered solids that have not been through the heat drying process are disposed of by land application. The Plant has a permitted treatment capacity of 96 mil gal per day (mgd) on an average annual daily flow (AADF) basis. The 2011 AADF for the Plant equaled 57.5 mgd. Currently, the permit for the plant issued by the Florida Department of Environmental Protection (FDEP) requires high levels of carbonaceous biochemical oxygen demand (CBOD5), total suspended solids (TSS) and nitrogen removal, as well as dechlorination and post aera-

Charlie Lynch is wastewater department chief engineer and Rory Jones is wastewater engineer at City of Tampa. Emilie Moore is project manager, Steve Tamburini is process engineer, and John Toomey is senior engineer at Tetra Tech in Tampa.

tion. Furthermore, the FDEP permit sets limits for recoverable nickel and a trihalomethane compound (dichlorobromomethane) and establishes requirements related to effluent toxicity. The major treatment processes of the Plant are shown in Figure 1 and include: High-Purity Oxygen (HPO) Carbonaceous Reactors Diffused Aeration Nitrification Reactors (DARs) Denitrification Filters

Figure 1. Howard F. Curren Advanced Wastewater Treatment Plant Process Schematic

January 2014 • Florida Water Resources Journal

Many of the treatment technologies employed at the Plant are modern; however, advances in biological nitrogen removal processes offer potential savings in operating costs. Also, other process enhancements and supplementary technologies could offer economic benefits. Since the current flows and loadings are well below design values, it may be possible to modify the treatment process to achieve nitrogen removal and increased efficiencies without building additional structures. Like many public entities, the City is facing significant financial constraints; therefore, potential optimization programs involving relatively small capital expenditures and the savings in operation costs must result in short payback periods. The operating budget for the Plant includes substantial costs for power and the purchase of methanol for the denitrification process. Due to the magnitude of these costs and increasing fiscal pressures, the City authorized Tetra Tech to develop and evaluate specific alternatives that could lead to reductions in operating expenditures. This work was conducted as part of the process optimization feasibility study.

Process Optimization Feasibility Study An initial assessment of the Plant identified four general areas where the plant operation could be optimized, resulting in potential energy savings and chemical reduction, and thus, reduced costs, including: Alternative 1 - Enhancing anaerobic digestion by increasing primary solids recovery. Alternative 2 - Reducing the nitrification requirements in the secondary basin by sidestream treatment of recycled ammonia through the SHARON® process (Alternative 2A) or CAST process (Alternative 2B). Alternative 3 - Carrying out suspended growth denitrification in the existing aeration basin to reduce methanol requirements in the denitrification filters. Alternative 4 - Evaluating alternatives for optimizing the HPO system. Alternative 1 explored enhanced primary clarification to increase the solids settling in the clarifiers with a chemical coagulant and sending more solids to digestion. Options evaluated included the addition of iron or aluminum salts upstream of primary settling to increase primary treatment efficiency and cogeneration as a result of increased anaerobic digester loadings. A bench-scale study using ferric chloride was developed by Tetra Tech and conducted by the City's laboratory and operations staff.

Table 1. Economic Sensitivity Based on 2008 Prices

Alternative 2 evaluated use of two technologies for sidestream processes to treat recycled ammonia-nitrogen and thereby reduce the oxygen demand in the main aeration basin. One was the SHARON® process (Alternative 2A), a biological process developed in Europe, and the other was the R-CAST® system (Alternative 2B), a physical/chemical process with recovery of ammonia for use as a fertilizer. Alternative 3 evaluated denitrification in the existing diffused aeration reactors (DARs) by setting up anoxic zones, thereby reducing oxygen demand in the DARs and chemical methanol needs in the denitrification filters. This is accomplished by creating anoxic zones within the activated sludge treatment process where nitrate can be reduced to nitrogen gas by facultative bacteria. This process modification would be implemented within existing basins and result in lower power consumption and decreased chemical consumption in the subsequent stages of treatment. Alternative 4 evaluated turning down or replacing the HPO system. The Plant has a cryogenic HPO generation process, with capacity to meet the oxygen demand for the full plant capacity. Since the current oxygen demand is less than the design capacity, excess HPO is being generated. This alternative evaluated turning off the HPO system and using mechanical aeration within the various reactors to provide the oxygen needed for CBOD5 removal in the initial stage of treatment. The costs associated with the different alternatives were developed utilizing the 2008 electrical and methanol costs. Additionally, the payback period for the proposed alternatives was calculated, as shown in Table 1. Alternative 3 appears marginal from an economic standpoint at current price levels for power and methanol; however, the analysis in-

cluded costs for a new floor-cover-diffused aeration system and the installation of an automated aeration control system. The replacement of the aeration system should be considered normal renewal and replacement and an automated aeration system would be a typical feature for such a large plant. If these two costs are removed from the analysis, suspended growth denitrification is very cost-effective, resulting in a payback period of less than two years. Savings associated with this option are anticipated to be approximately $400,000 per year. For Alternative 4, the existing HPO generation system is producing significantly more oxygen than needed to provide removal of CBOD5. This situation results from a limited turndown capability and there does not appear to be a simple and effective means of modifying the HPO generators to correct the situation. If the HPO generation systems were to be shut down, the mechanical aerators within the HPO train can be used to provide aeration in a conventional manner; however, the tank headspaces will need to be vented. Based on these findings, it was recommended that the City further evaluate the viability of Alternatives 3 and 4.

Tampa Takes the Next Step The evaluation of Alternatives 3 and 4 include the development of a wastewater process model using GPS-X process simulation software. For Alternative 3, the model is used to help identify potential on/off aeration schemes in the DARs in an effort to achieve denitrification upstream of the denitrification filters to decrease methanol use. For Alternative 4, the model is used to check the viability of conContinued on page 8

Florida Water Resources Journal • January 2014

Continued from page 7 verting the HPO reactors to air-activated sludge reactors in an effort to decrease aeration cost and allow for denitrification in the DARs. Alternative 3 Modeling For Alternative 3, a calibrated GPS-X model was prepared to demonstrate how on/off aeration could be implemented in the DARs to maximize denitrification, as shown in Figure 2. The amount and rate of denitrification is highly dependent on the amount of CBOD available. A bypass around the HPO reactors can supply up to 30 percent of the primary effluent flow directly to the DARs to increase the CBOD available for denitrification.

Despite operating the HPO reactors with a low solids retention time (SRT) of less than one day, limited nitrification is achieved in the HPO reactors (typically effluent nitrate concentrations between 6 to 12 mg/L) due to waste activated sludge (WAS) being recycled from the DARs to the HPO reactors. The HPO bypass and limited nitrification in the HPO reactors allow for high-rate denitrification to occur if anoxic conditions are introduced at the beginning of the DARs. Several variables were modeled to optimize denitrification, including the percent of primary effluent that bypasses the HPO reactors, static anoxic zones, and variable timing of on/off aeration. It was found that the optimal bypass flow was 30 percent of the influent

Figure 2. Alternative 3 Model Configuration

Figure 3. Denitrification Performance for Alternative 3 Using On/Off Aeration

January 2014 â&#x20AC;˘ Florida Water Resources Journal

flow rate. Bypass above this percentage resulted in increased effluent ammonia concentrations when operating at a constant SRT. The increased bypass flow changes the bacterial population distribution between facultative and autotrophic nitrifying bacteria. It was found that as more facultative bacteria are grown in the DARs, less nitrifying bacteria are present, unless the mixed liquor concentration is increased, which would result in overloading the clarifiers. With a 30 percent bypass flow, it was found that the optimal denitrification performance was obtained using an on/off aeration scheme compared to the use of static anoxic zones. Each DAR is divided into six cells that can be operated as different aeration zones. The optimal denitrification performance was found to occur when the first zone was dedicated as anoxic, while Zones 2-5 were operated in an on/off aeration scheme. Zone 6 was continuously aerated to maintain aerobic conditions entering the clarifiers. The on/off timing was modeled using equal on/off cycles of four hours at current loadings. The denitrification performance was found to be 25 percent better using this approach, compared to using two static anoxic zones. The modeling showed that the readily biodegradable influent CBOD was completely consumed by the end of Zone 1, indicating that high-rate denitrification did not occur beyond Zone 1. Denitrification occurred during the off cycles using solubilization of particulate and colloidal CBOD, and endogenous respiration as the carbon sources. Using two static anoxic zones did not provide as much time for endogenous respiration to occur, resulting in less denitrification, which is why it did not perform as well as on/off aeration. At the current plant loading, the modeling showed that between 6 and 10 mg/L of nitrate could be denitrified in the DAR without effecting nitrification efficiency. Figure 3 shows the denitrification performance under maximum nitrogen concentrations at current flows. By denitrifying in the DARs, less methanol is required in the denitrification filters. The Plant currently doses 2.9 mg of methanol for every mg of nitrate denitrified in the filters. This dose is close to the theoretical minimum of 2.86 mg of methanol per mg nitrate, indicating there is little room for optimizing the methanol dose rate. Denitrifying 10 mg/L of nitrate in the DAR will save approximately $1.1 million annually, based on current methanol pricing of $1.50 per gal. As flows increase at the Plant, additional aeration time will be required to complete nitrification, which will decrease the off-cycle times, resulting in a decrease in savings. In addition to the

methanol savings, aeration savings would be realized with anoxic oxidation of CBOD in the denitrification process, which is estimated at $81,000 per year. Alternative 4 Modeling For Alternative 4, the HPO reactors in the GPS-X model were converted to conventional air activated sludge (CAS) reactors, as shown in Figure 4. The modeling showed that for this alternative, the availability of CBOD in the DARs was still the limiting factor for optimizing denitrification. The model was run at conditions that allowed for limited CBOD removal in the CAS reactors by operating at a low 0.5-day SRT and a low DO concentration of 0.2 mg/L, which resulted in relatively high concentrations of CBOD in the DARs. It was found that operating the DARs using a Ludzack-Ettinger (LE) process (static anoxic zone at the head of the DARs without mixed liquor recycle) resulted in denitrification of 12 to 16 mg/L of nitrate in the DARs, while using an on/off aeration control resulted in only denitrifying 8 to 12 mg/L of nitrate. The DAR SRT was maintained at 15 days for both model runs, which resulted in the same effluent ammonia concentration of approximately 0.5 mg/L. Figure 5 shows the denitrification performance for Alternative 4 under maximum nitrogen concentrations at current flows. The estimated methanol savings for Alternative 4 using current methanol prices of $1.50 per gal increases to approximately $1.65 million a year due to additional denitrification in the DARs. In addition to methanol savings, Alternative 4 will realize significant aeration savings. The net reduction in power consumption anticipated with this alternative is approximately 3,680,000 kWh/year, which would decrease greenhouse gas emissions by over 2,900 tons/year. Cost savings under this scenario are expected to equal approximately $250,000 a year and the capital investment would be relatively small. On/off aeration had better denitrification performance for Alternative 3, but it did not have better performance for Alternative 4. For Alternative 4, there was adequate CBOD available for denitrification throughout both anoxic zones in the LE process. While overall denitrification performance was better, there are several concerns using this approach. Denitrification within the DAR clarifiers might be a problem, considering there will be relatively high concentrations of nitrate going to the clarifiers, with an increased oxygen uptake rate due to more CBOD removal in the DARs. While the model predicted good overall performance with the highest denitrification for Alternative 4, operating the HPO as CAS reactors with low SRT

Figure 4. Alternative 4 Model Configuration

Figure 5. Denitrification Performance for Alternative 4 and low DO could result in poor settleability. Predictions of changes in settleability cannot be accurately modeled; therefore, a pilot demonstration should be performed to demonstrate that good settleability can be maintained in both the CAS and DARs.

Tampa Plans for Implementation Treatment plants are designed to operate at a design capacity that is typically higher than current flow and loading conditions. While plants are underloaded, there is usually ample opportunity to optimize the process and operate with a different mindset when at capacity. The Plant is currently loaded at about 60 percent of design capacity. The City has taken a systematic approach of performing studies and evaluating alternatives, and has begun to implement the best optimization strategies by integrating the necessary im-

provements within planned capital replacement projects. The aeration diffusers in the DARs need to be replaced. The design of the aeration diffusers in the DARs will incorporate the ability to operate in on/off aeration mode as described in Alternative 3. This will allow the City to take advantage of some methanol savings through denitrification in the DARs while the HPO system is in operation. The City is still evaluating the possibility of temporarily converting the HPO reactors to CAS reactors while the plant is underloaded to maximize denitrification upstream of the denitrification filters as described in Alternative 4. The new aeration system in the DARs will be designed to incorporate such a conversion if it is made in the future. Implementing either alternative will result in significant operational savings that can be used to fund future optimization and capital improvement projects in the future.

Florida Water Resources Journal â&#x20AC;˘ January 2014

T E C H N O L O G Y

S P O T L I G H T

Poston Applied Technologies PAT 949 Combination Truck The PAT 949 Combination Truck, at first glance, looks like a vacuum truck; however, that is only part of the story (and its capabilities). The PAT 949 Combination Truck can vacuum, but the Polston Process™ also combines downhole pumping capabilities. The truck overcomes the limitations of vacuum technology, but the “rest of the story” is that it is capable of removing material from very wet and/or deep conditions. The proprietary technology, including both the equipment and process, was developed to reach and remove debris (sand) that heretofore has not been removed because of the physical (gravity) limitations of vacuum technology. Having an understanding of the natural limitations of vacuum technology is critical to understanding this product’s role in the maintenance of wastewater collection and treatment systems while in operation. The equipment has been designed to vacuum, as well as reach and remove, material that vacuum technology cannot, challenging the limits of the current maintenance paradigm. There are two naturally occurring limitations to all vacuum technology: depth and water. Depth – As for the limitations associated with debris being located at a very deep level, consider that a perfect vacuum can only “suck” clean water about 30 ft vertically. Why does this matter? Because many pipes and other structures are either buried very deeply or have high walls to overcome. When you consider the height of the debris box/tank above the ground and add debris (sand) to the water, which increases the density, the effective height (or suction reach) is shortened significantly. This reduces

What is a Combination Truck?

the effectiveness of vacuum capabilities. (Source: http://answers .yahoo.com/question/index?qid= 20080220174717AAktnxG ) Water – As for the limitations associated with too much water, consider that a vacuum removes air; therefore, it accumulates water and debris in the debris box/tank. In wet conditions (e.g., structures with a lot of water), the debris box/tank will fill up with water sooner than with debris. When this occurs, the operation must cease so that the debris box/tank can be emptied. Once the debris box/tank is full of water or debris, it must be emptied. To further illustrate: given very wet conditions (lots of water present), two problems emerge for vacuum technology and both increase cost. First, the water keeps filling up the debris box/tank so removing the debris (sand) takes much longer. This limits the rate of debris removal, and the longer it takes, the more it costs. Secondly, the removed debris material must go to a landfill, which is always required for wastewater systems. But, landfills only take “paint filter dry” debris, which is material with no “free” water. Costs increase when material is handled multiple times to remove excess water. The company’s process removes water; therefore, it accumu-

lates only debris (sand) in the debris box/tank. In wet conditions, the PAT 949 Combination Truck debris box/tank fills up with debris because the process continuously separates, under pressure, the water from the sand until the debris box is filled with the “paint filter dry” material, which can then be immediately disposed of, with no additional handling. In 2012, Polston Applied Technologies introduced and demonstrated its new truck throughout Florida. It features the same vacuum capabilities familiar to the water and wastewater utility industry, as well as combining a down-hole system that adds expanded capabilities to the maintenance tool bag. In order to spotlight the truck, the gravitational (or natural) limitations of vacuum technology are an important starting point in order to understand how it expands the maintenance capabilities available to the industry. The truck handles dry, damp, wet, and submerged debris from depths to 150 ft below the surface. The truck was designed to remove debris, such as sand; rag material; and fats, oils, and grease (FOG), from structures in the wastewater collection and treatment systems while they remain in operation.

The truck combines both vacuum and down-hole capabilities. The vacuum system is equipped with a 3650-cfm blower and the down-hole system begins with a 2500-gpm minimum capability. One of the most unique features of the truck is that both capabilities can be interchanged instantly with a flip of a switch. Both the vacuum and downhole systems are mounted on the same Peterbilt 367 Chasis. The truck is equipped with a minimum of 800 ft of jetter hose, with swivel and tilting action for large-diameter pipe cleaning. Finally, the 49-ft knuckleboom crane, which is coupled with a proprietary dripless, telescoping (vacuum and pressure) tube system, provides the dexterity and reach required to remove debris from collection and treatment system structures. The truck’s patented process removes debris and “paint filter dry” material from wet or submerged conditions. For dry or damp material, the truck assigns its vacuum technology the task. However, if there are significant amounts of water present, then the work must stop frequently because the vacuum collects the water that must be decanted, limiting the run time and the amount of sand removed in each load. For wet and submerged conditions, the truck calls on its proprietary down-hole technology capable of removing sand until loads of “paint filter dry” material are generated and ready to be taken directly to the landfill for final disposal. The PAT 949 Combination Truck “flips the switch” and transitions to meet the demands of any conditions encountered.

Technology Spotlight is a paid feature sponsored by the advertisement on the facing page. The Journal and its publisher do not endorse any product that appears in this column. If you would like to have your technology featured, contact Mike Delaney at 352-241-6006 or at mike@fwrj.com.

January 2014 • Florida Water Resources Journal

Florida Water Resources Journal â&#x20AC;˘ January 2014

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Starting Up an Underloaded Biological Nutrient Removal Process Craig Fuller, Charles Nichols, Mark Addison, David Wilcox, and Dwayne Kreidler n wastewater treatment facilities, some unit processes can be designed to be extremely flexible for varying flow rates and loads of wastewater. Examples of unit processes that will sometimes operate better at lower than designed loading rates include mechanical bar screens, tertiary filters, pump stations, and clarifiers. Processes that are difficult to operate in an underloaded state are biological treatment processes, including aeration basins; biological nutrient removal (BNR) systems; oxidation ditches; anoxic basins; and anaerobic basins for biological phosphorous removal. This difficulty is compounded when starting up new or altered facilities, especially when the Facility has permitted nutrient discharge limits. This article presents an example of an extremely underloaded startup (less than 50 percent of capacity and less than 30 percent total nutrient capacity) and some key metrics and potential pitfalls to consider when starting up or operating such a facility.

Facility Expansion Pre-Expansion Facility Polk County’s Northeast Regional Wastewater Treatment Facility (Facility) was an existing wastewater treatment facility rated for an average annual treatment capacity of 3 mil gal

per day (mgd), with a maximum month influent five-day carbonaceous biochemical oxygen demand (CBOD5) of 246 mg/l and Total Kjeldahl Nitrogen (TKN) concentration of 40 mg/l. The Facility is located near the intersection of Interstate 4 and U.S. 27, in close proximity to theme parks and near the border to Osceola County, Lake County, and Orange County. The Facility typically discharges a portion of its effluent to rapid infiltration basins (RIBs) for aquifer recharge. The RIBs have a receiving permitted limit of 12 mg/l of nitrogen as nitrate to prevent a buildup in the soil. The existing biological treatment unit process consisted of two Carrousel-type oxidation ditches, each rated for 1.5 mgd. Each oxidation ditch has a volume of 0.75 mil gal (MG) for a hydraulic retention time (HRT) of 12 hours. With a designed operating mixed liquor suspended solids (MLSS) concentration of 3,500 mg/l, a solids retention time (SRT) of 8.8 days is achieved. The ditches did not have anoxic zones and were capacity-limited when approaching their aeration limits due to their limited ability to remove nitrates through biological denitrification. The upstream and downstream unit processes will not be discussed significantly due to their ability to handle fluctuating flow more easily. Downstream processes are af-

Figure 1. Schematic Layout of Biological Nutrient Removal: One Operational Mode

January 2014 • Florida Water Resources Journal

Craig Fuller, P.E., is a senior water and wastewater engineer at URS Corporation in Bartow. Charles Nichols is a regional wastewater treatment plant manager and Mark Addison, P.E., is the capital investment program manager with Polk County Utilities. David Wilcox, P.E., is the water/wastewater group manager at URS Corporation in Tampa. Dwayne Kreidler, P.E., is a senior engineer at ARCADIS in Orlando.

fected by the ability of the biological processes to perform correctly. When anoxic conditions are not achieved prior to entering the clarifiers, it is common for denitrification to occur in the clarifiers, leading to a condition known as sludge “pop-ups.” Expanded Facility Design When the Facility expansion design began, the area was experiencing significant growth, with new development being permitted and constructed within the service area. When the original design began in 2006, it was expected that the Facility would be receiving more than 3 mgd by the start of 2010. To accommodate the expected growth, the Facility was originally thought to require 9 to 12 mgd of treatment capacity. Although growth slowed, it was expected that the Facility still had an immediate need of 6 mgd of treatment capacity, with the capability to upgrade to 9 mgd in the future. To compound the hydraulic capacity requirements, influent sampling during the preliminary design indicated the maximum month CBOD5 strength of the wastewater had increased from 246 mg/l to approximately 600 mg/l and the influent TKN had increased from 40 mg/l to approximately 65 mg/l. The increase in loading meant that the future Facility would need to provide significantly more oxygen per unit volume of wastewater on an actual oxygen requirement (AOR) basis than the original design contemplated. The oxygen demand for the expanded Facility was estimated to be 52,736 lb/day (AOR) based on the design flow rate of 6 mgd versus 12,384 lb/day for the original 3mgd design. To augment the existing oxidation ditches, a BNR process was proposed with ex-

tensive flexibility. The process has a minimum treatment volume of 2 MG, with a “floating” equalization volume of 1.5 MG, for a total volume of 3.5 MG. The design MLSS for the Facility was increased to 4,000 mg/l to decrease the volume required so that an SRT similar to the original design could be maintained. This also maintained similar hydraulic retention tine (HRT) metrics with the existing plant. The BNR is split into four equal-size tanks, with each tank having three aeration zones in the center and two nonaerated zones, one at each end. The air can be distributed through any, all, or none of 12 total aeration zones, each with a capacity of approximately 1,400 standard cubic feet per minute (scfm) per zone using fine bubble aeration. The eight zones that do not have aeration are located at each end of each tank. At the western end of each tank, recycling propeller pumps allow for the return of up to 6 mgd per propeller pump to the eastern end of the tank. One of the intended operational modes of the biological treatment (as depicted in Figure 1) has the raw wastewater and return activated sludge (RAS) enter the BNR at the east end of Tank 1 going west. The mixed liquor path changes direction and travels north to Tank 2, then heads east. At the eastern end of Tank 2, the mixed liquor enters Tank 3, changes direction, and heads West in Tank 3. Finally, the mixed liquor enters Tank 4, heads east, and exits the process at the east end. The flow can either go to the existing oxidation ditches for polishing treatment, with the oxidation ditches operating either in parallel or in a series, or bypass them and go to the clarifiers for clarification. With key recycle pumps in the BNR, the nitrates created by nitrifying bacteria can be returned to anoxic zones for nutrient removal. In the mode of operation discussed, the biological treatment system was envisioned to be operated with the influent BNR tank, Tank 1, having an anoxic zone at the front, followed by an aerobic zone. The recycle pump in Tank 1 was intended to be on to allow for nitrogen recycle and nutrient removal. The western end of Tank 2 was intended to generally be an aerobic zone, followed by anoxic at the east end as the mixed liquor enters Tank 3. The eastern end of Tank 3 was intended to be anoxic, followed by aerobic at the western end, with the recycle pump in Tank 3 being on for nitrogen recycle. Finally, the western end of Tank 4 was intended to be aerobic, followed by the eastern end being anoxic. Following the anoxic area in Tank 4, the mixed liquor flow would either go to clarification or enter an aerobic zone in Oxidation Ditch #1, followed by an anoxic zone. The mixed liquor in Oxidation Ditch #1 would then travel to Oxidation Ditch #2 for a

final aerobic zone, followed by an anoxic zone. Denitrification is accomplished by recycling nitrified mixed liquor from Zone 5 in Tanks 1 and 3 to Zone 1 in Tanks 1 and 3, respectively, which operate in an anoxic mode. Tank 4 has an anoxic zone present near the outlet to allow for denitrification that had not previously occurred, increasing the ability of the clarification if the oxidation ditches are bypassed. The amount of operational flexibility built into the BNR process requires a determination of how large the anoxic zones and aerobic zones will be, the selected oxidation reduction potential (ORP) for process

control, and a selection of the amount of nitrogen recycle flow desired. The process calculations will be discussed. Facility Influent After Expansion The housing market had a sudden downturn during the design, and the slump continued throughout the construction of the Facility. The result was that the influent flow was only about 2.5 mgd when the expanded Facility was ready to be placed in operation. With all package plants in the same area diverted to the FaContinued on page 14

Florida Water Resources Journal • January 2014

Continued from page 13 cility, maximum month influent flows of approximately 3 mgd were recorded. In addition, the strength of the influent wastewater was more in line with what was seen prior to the peaking events, or in the range of 300 mg/l CBOD5. The influent nitrogen was still high at about 50-60 mg/l TKN, but not near the levels routinely seen during the design period. With all four BNR tanks and both oxidation ditches in operation, the HRT was determined to be approximately 28 hours and the SRT, excluding equalization, would be 22.3 days based on a MLSS of 4,000 mg/l as designed. The new RAS pumping system was capable of being tuned to 3 mgd at a concentration of approximately 8,000 mg/l, and was not an operational problem for the process. While this extensive aeration capability and long SRT leads to relatively easy treatment of CBOD5 and quick nitrification of ammonia, it can be tricky to operate the Facility under these conditions and still meet effluent nutrient limits. Upon initial startup of the facility, some of the parameters were adjusted to allow for the Facility to operate better, such as lowering the MLSS to about 2,000 mg/l, resulting in an SRT of approximately 11 days. Operations staff was still recording a steady increase in effluent nitrate levels; in some instances, nitrate levels exceeded influent nitrogen levels. It was also noted that the effluent quality of wastewater leaving the BNR was sometimes better than the effluent quality of the wastewater leaving the oxidation ditches. It is speculated that nitrogen fixation and ammonification was occurring, where nitrogen in the air was being converted to ammonia (Leschine, et al., 1988) then nitrified to nitrates due to the presence of anaerobic conditions, followed by very aerobic conditions. Although evidence indicated nitrogen fixation, more data would be necessary to prove it was occurring. Ammonification of TKN and nitrification was evident due to the increase in nitrates through the process.

actually measured, and influent flow would be close to 3.5-4.5 mgd with the diversion of flow from existing package treatment plants in the service area. Recalculation of the ideal unit process parameters was performed in order to allow the processes to work at their peak. While the BNR has the capability of aeration and anoxic, among other treatment capabilities, if the zones are not sized effectively, the treatment processes can get out of control, leading to large swings in both oxygen demand and effluent water quality from the biological unit process.

Operational Calculations

Anoxic Zone Requirements The primary anoxic zone was the next item to be considered. The specific denitrification rate (SDNR) was calculated based on the typical minimum temperature of the wastewater. The size of the anoxic zone required is based on the nitrogen to be denitrified, the SDNR, and the volatile portion of the MLSS, or mixed liquor volatile suspended solids (MLVSS). Because of the need for CBOD5 in the denitrification process, it is critical that the anoxic zone be located at the front of the biological process to allow it to be most effective. Based on the revised influent characteristics,

Process Recalculations Operations staff was experiencing difficulties meeting effluent nitrate requirements. Process calculations were revisited utilizing influent flow rates of 2.5-3.5 mgd with biochemical oxygen demand (BOD) and TKN concentrations of 275-300 mg/l and 50-60 mg/l, respectively. The sizing of ideal treatment unit processes was considered based on both current and projected flow rates and loadings. It was expected that the nutrient loading would be much higher than what was

Food to Mass Ratio and Solids Retention Time The first items to consider are the food to mass (F/M) ratio and the SRT. The BNR was installed with fine bubble aeration and should, therefore, not be left without water in the basin. To lower the SRT to approximately eight days, as intended, both oxidation ditches would have to be removed from the treatment process and the MLSS would have to be lowered. It was calculated that if the MLSS was set to approximately 2,500 mg/l, the SRT would be 7.9 days, excluding equalization volume. This would also achieve an F/M ratio of approximately 0.18-0.2, which is ideal for the treatment process. If the process were to be started up with all bays functioning and the MLSS at 4,000 mg/l, the F/M ratio would be only 0.07, or far below the levels needed to sustain the process. The following are examples of the equations used to size the SRT and F/M ratios (Metcalf & Eddy, et al., 2003):

It is more common to calculate the SRT with the rate of wasted sludge, but the calculations can be compared to each other to verify actual yield of MLSS from BOD and to confirm the calculations based on wasting rate are correct.

January 2014 • Florida Water Resources Journal

and a flow rate of 3 mgd, the minimum size of the anoxic zone was determined to be 0.477 MG and the ideal size was determined to be approximately 0.729 MG, which allows for conversion of some of the organic nitrogen to ammonia/ammonium. The following are examples of the equations used to size the anoxic zone (Metcalf & Eddy, et al., 2003).

The volume equation for the anoxic sizing allows removal of the influent TKN as ammonia, and while increasing that value, allows conversion of organic nitrogen as BOD to ammonia/ammonium, which can occur if slightly anaerobic conditions exist at the end of the anoxic zone. The first volume calculation of the size of the anoxic volume has no safety factor and is typically the minimum volume to be effective only for denitrification. The nitrogen removal equation is somewhat conservative; the low wastewater temperature is actually about 26°C and not all TKN can be removed through denitrification. These values are higher than the “rule of thumb” volumes for hydraulic retention times of 2-4 hours due to higher than typical influent TKN values. Recycle Rate The nitrogen recycle rate is typically determined by the target effluent nitrogen. There is typically no penalty for over-recycling to the anoxic zone, except that CBOD5 will be utilized early in the treatment process. Using too much CBOD5 early for aeration can lead to the need to add a carbon source later in the process, adding to the expense of the operation. With a properly-sized anoxic zone, and a recycle rate of five times influent (3 mgd influent in this case), the nitrate effluent was calculated to be 6 mg/l. Therefore, the recycle rate was set at this rate to allow for maximum reduction of nitrate in the effluent. The following equation is used to calculate the required recycle rate for removal of nitrates (Metcalf & Eddy, et al., 2003).

Oxygen Requirements The AOR, without a safety factor, was calculated to check if the process was providing Continued on page 16

Florida Water Resources Journal â&#x20AC;˘ January 2014

Continued from page 14 theoretical sufficient oxygen for the influent BOD and TKN. The following is a calculation

of the AOR in lbs for the existing system: Note that a credit was given for anoxic use of nitrates, which is typically on the order of 2.86 lbs of oxygen per lb of nitrate reduced (Metcalf & Eddy, et al., 2003). There was not a safety factor of 1.1 for the kS due to the use of real experimental efficiency in the aeration calculations in later calculations (Ott submittal, 2009). Finally, the aeration volume was calculated to see if the process had sufficient volume to achieve full BOD oxidation and nitrification. The following calculations show the minimum aerobic volume required to achieve full BOD oxidation and nitrification

(Metcalf & Eddy, et al., 2003): Note that these calculations exclude typical design safety factors of 2.5 and are truly the minimum. Even with the safety factors, it can be seen that the rate-limiting step for oxidation is nitrification. Because of the high temperature of the wastewater, the volume required in practice is extremely limited and is easily met, which is why dissolved oxygen (DO) had to be decreased to match the true demand. With the DO decreased to 0.19, the total time required for full nitrification is approximately 0.167 days, or a volume of 0.5 MG for the first aerobic zone. This approximately matches the values seen in the field. Process Calculation Comparison Table 1 is a comparison of the actual wastewater and process demands versus the design values of the plant. The 6-mgd design example provided indicates what the process values would be if the full volume of the BNR and oxidation ditches were utilized, if the design MLSS were held, and the maximum aeration rate were utilized. It is not intended to indicate an actual operational condition. Operational Modifications Due to the manner in which the recycle pumps were installed, it is critical that nitrification is achieved in the first tank in which the wastewater enters, and that the nitrified wastewater is recycled back to the front of the tank

Table 1. Calculated Process Values For Operation

January 2014 • Florida Water Resources Journal

into the anoxic zone. This will allow for a large amount of nitrogen conversion early and for much of the nitrogen to leave the process as offgas. Based on the process installed, at least two of the zones in the influent tank (Tank 1) had to be anoxic, and a third zone ideally would be slightly anoxic. The fourth zone then must be aerobic, with an ORP level high enough to nitrify (not high enough to satisfy all of the CBOD5 demand) and low enough not to bleed the aerobic environment into the fifth zone where the nitrogen recycle pumps sit recycling the nitrates. With operational trial, this level was determined to be in the range of +25 to +50 ORP in the fourth aeration zone by splitting air between the third zone and fourth zone, having the probe in the fourth zone. Note that the exact set point requires some trial and error and will vary greatly based on the temperature of the wastewater and actual organisms present. The second tank (Tank 2) was utilized to stabilize the wastewater, allowing for organic nitrogen conversion and additional denitrification. The air was spread uniformly with a target ORP in the range of 0 mV +/- to keep the wastewater active and in the anoxic range, but not overaerate it. This will allow for conversion of organic nitrogen to ammonia which can take time, except the nitrogen that is assimilated as solids. The process in Tank 1 was emulated in Tank 3 with slightly lower ORP set points. Tank 3 would then nearly fulfill the CBOD5 demand for the wastewater. The recycle rates are set at similar flow rates to allow for optimal nitrate removal, reducing the minimum nitrogen effluent to close to 6 mg/l. By satisfying the oxygen demand in Tank 3, Tank 4 is able to operate in a similar manner to Tank 2, stabilizing the wastewater and allowing for denitrification before the MLSS goes to the clarification unit process for solids separation. The ORP set point, at the effluent of Tank 4, controls the aeration in Tank 4. To allow for faster and tighter control for the air to Tank 4, it is ideal to have a feed-forward loop by mixing the MLSS with the nitrogen recycle pump in Tank 4, as nearly all treatment has already occurred and the penalty will not be great, even if a “slug” is encountered. With the volumes and aeration rates for the processes calculated, it was determined that, even with a significant safety factor, the oxidation ditches were not needed in the immediate future to meet effluent quality if all four tanks of the BNR are in operation. Not only were they not needed, the effluent water quality would be better without them and the cost of Facility operation would decrease. The reason for the effluent quality being better without the oxidation ditches is due to the inability to “turn down” aeration below 60 percent of speed, or approxi-

mately 36 percent of aeration capability. To achieve better results and additional recycle return, it was determined that Tanks 1, 2, and 3 should be operated in parallel, and Tank 4 should flow in the opposite direction, used as a completely stirred reactor and final anoxic basin. This will allow a high ORP set point in Zone 4 of each tank, roughly +100 mV, and the nitrogen recycle pump can be operated in each tank. This leads to the seventimes-influent recycle rate, and still allows the feed-forward loop in Tank 4 to function. Figure 2 depicts this proposed mode of operation. Treatment Results With the modifications to the wastewater plants operation as described, the wastewater treatment operators are able to achieve effluent with CBOD5 at near 0 mg/l, and TKN in the range of 1.5–3 mg/l with TN from 3–5 mg/l. This is accomplished while delivering only about 3,000 scfm of air to the BNR process during peak events. While the process design equations indicated the recycle rate of 5*Q will yield a finished quality of 6 mg/l nitrate (Ekama, G. et al., 2008), empirical results from testing have shown that recycle rates of 5*Q can yield nitrate in the range of 3 mg/l, which is approximately what has been measured (Pennsylvania Department of Environmental Protection). The effluent quality may not be possible when the facility’s influent levels increase as the nitrogen recycle rate relative to influent will decrease, but it can be close to that number through careful monitoring of the facility. Noted items that must be monitored are the F/M ratio, along with SRT and HRT. Similar results may be possible when flows approach 4.0– 4.5 mgd, and it is necessary to add an oxidation ditch as it will be used in series with the BNR. The target ORP values may have to decrease to prevent complete oxygen satisfaction of the treatment process in the BNR, allowing the oxidation ditch to operate at low speed to have both aerobic and anoxic zones present within the treatment process. If there isn’t sufficient CBOD5 remaining, the anoxic zone will not be large enough to prevent denitrification in the clarifiers, which can be a serious issue. Alternatively, the mode of the BNR operation could be operated with Tanks 1 through 3 in parallel, as shown in Figure 2 and described previously. To achieve similar results at a flow of 6 mgd, BNR Tanks 1–3 could run in parallel, with relatively high ORP set points at the west end. This would keep a high recycle rate ([6 mgd*3 Nrcy + 6 mgd RAS]/6 mgd-Q = 4*Q), allowing Tank 4 to operate as an effluent anoxic area with minimal aeration provided early to keep the mixed liquor ORP in the anoxic range

Figure 2. Schematic Layout of Biological Nutrient Removal: Proposed Operational Mode and remove nitrogen gas that may still be attached to solids in the process. The oxidation ditches would be utilized as final polishing for additional removal of nutrients, which would require a lower ORP set point in BNR Tanks 1– 3 or a late addition carbon source. With the existing oxidation ditches operating, and with a recycle rate of approximately 6 mgd each, the total recycle rate would be approximately 6*Q, or slightly less than the current 7*Q. Potential Startup Pitfalls One major pitfall of the BNR process at severe underloading can be overaerating. Due to the capability of the BNR process to deliver air far beyond the potential demand, it is easy to overtreat the wastewater early in the BNR, with the remainder of the tank supplying air that is not “demanded” by the organisms present. This can be seen by taking nitrogen profiles. When operated in a series, an early tank, such as Tank 1, may have effluent with nitrates of 6 mg/l and less than 1 mg/l of ammonia going into Tank 2. However, Tank 3 may have ammonia at 2 or 3 mg/l, with nitrates at 12 mg/l. This occurs due to ammonification and, potentially, biological nitrogen fixation, or the ability of bacteria to convert nitrogen gas into ammonia or nitrate. To prevent this, the ORP can be decreased in Tank 1, allowing more ammonia to bleed into the next tank. The process must be more tightly controlled to prevent extremely anaerobic conditions (below -50 mV) from existing in later stage tanks. Another pitfall is undersizing the initial anoxic portion of the treatment process. If the initial anoxic portion of the treatment process is not calculated, and it is sized too small, it may not be sufficient in size to have meaningful den-

itrification. For example, attempting to operate Tank 1 with only the first zone of Tank 1 as anoxic, or between 0.1 and 0.15 MG of anoxic volume, resulted in nitrate levels of about 50 mg/l leaving Tank 1. Further, the process had an inability of denitrifying to near the required levels within the process due to depleted CBOD5 in Tanks 2 through 4. This was solved by moving the aeration zones to the west and, further, by operating Tanks 1 through 3 in parallel. By sizing zones properly and keeping track of key operational metrics of a BNR process, startup can quickly be followed by smooth operation.

References • Goronszy, M.C., Bian, Y., Konicki, D., Jogan, M., and Engle, R., 1992, Oxidation Reduction Potential for Nitrogen and Phosphorous Removal in a Fed-Batched Reactor, Proceedings Water Environment Federation Conference. • Leschine, S. B., Holwell, K., Canaleparola, E., 1988, Nitrogen Fixation by Anaerobic Cellulolytic Bacteria, Journal Science, pages 11571159. • Metcalf & Eddy, Tchobanoglous, G., Burton, F.L., Stensel, H.D., 2003, Wastewater Engineering: Treatment and Reuse, Chapter 11, McGraw and Hill. • Ekama, G., Wentzel, M.C., Henze, M., 2008, Biological Wastewater Treatment: Principles, Modelling, and Design, Chapter 5, IWA Publishing. • Copithorn, 2002, Pennsylvania Department of Environmental Protection, Nutrient Control Seminar, Transparency 64. • Ott GmbH & Co., 2009, Northeast Regional Wastewater Treatment Facility Expansion, Specific Oxygen Transfer Efficiency Testing

Florida Water Resources Journal • January 2014

2014 FWPCOA OFFICERS & COMMITTEE CHAIRS CORPORATE OFFICERS • President Jeff Poteet (239) 389-5181 jpoteet@marcoislandutilities.com

• Vice President David Denny (386) 878-8100 ddenny@deltonafl.gov • Past President Raymond Bordner (727) 527-8121 h2oboy2@juno.com • Secretary-Treasurer Rim Bishop (561) 627-2900, ext. 314 rbishop@sua.com • Secretary-Treasurer David Clanton (386) 758-5452 theclantongang54@gmail.com

REGIONAL OFFICERS Region 1 • Director Odis Carter (850) 875-4045 odiscarter@tds.net • Chair Not available at press time • Vice Chair Not available at press time • Secretary-Treasurer Tom Walden (850) 980-5161 tjwalden@cs.com

Region 2 • Director Scott Anaheim (904) 665-8415 anahsa@jea.com • Chair Josh Parker (904) 665-6052 parkje@jea.com • Vice Chair Larry Johnson Johnlarry1953@att.net • Secretary-Treasurer David Ashley (904) 665-8484 ashldd@jea.com • Secretary-Treasurer-Elect Robert Boyle (904) 665-6052 boyrf@jea.com

Region 3 • Director Wendell Maxwell (321) 863-6765 wendell.maxwell@brevardcounty.us

• Chair Russ Carson (321) 749-5914 John.r.carson@nasa.gov • Vice Chair Kevin Shropshire (407) 246-3067 Kshrop2000@hotmail.com • Secretary Wayne Gauler dverch@gmail.com • Treasurer Bobby Potts (321) 867-3042 bgp81844@aol.com

Region 4 • Director Christina Pellegatti (727) 582-7023 clpellegatti@gmail.com • Chair Kelvin Melton KelvinMelton00@gmail.com • Vice Chair Kimberly Ciranko (727) 893-7497 Kim.Ciranko@stpete.org • Secretary Debra Englander (727) 892-5633 debrae7@juno.com • Treasurer Janet DeBiasio (727) 892-5640 Janet.Debiasio@stpete.org

• Vice Chair Vince Munn (561) 381-5354 vmunn@pbcwater.com • Secretary-Treasurer Greg Miegl (954) 232-1235 greg.miegl@gmail.com • Secretary-Treasurer-Elect Patti Brock (561) 493-6261 pbrock@pbcwater.com

Region 7 • Director Renee Moticker (954) 967-4230 rmoticker@yahoo.com • Chair John Feaster (954) 921-3288 jfeaster@hollywoodfl.org • Vice Chair Nigel Harris (954) 921-3288, ext. 8741 nharris@hollywoodfl.org • Secretary Linda Vargas (954) 828-7501 lindavargas@comcast.net • Treasurer Laurence K. Duemmling larry_duemmling@yahoo.com • Secretary-Treasurer-Elect Tim McVeigh (954) 683-1432 tim.fwpcoa@comcast.net

Region 5 • Director Stephen Utter (772) 978-5220 SUtter@covb.org • Chair Brad Macek (772) 770-5045 • Vice Chair George Horner (772) 873-6400 GHorner@cityofpsl.com • Secretary-Treasurer John Lang (772) 559-0722 jflang2012@gmail.com

Region 6 • Director Phil Donovan (561) 586-1708 R6Donovan@aol.com • Chair Pat Lyles lexus05@bellsouth.net

January 2014 • Florida Water Resources Journal

Region 8 • Director Jon Meyer (239) 989-9791 JMeyer@uswatercorp.com • Chair Justin Martin (786) 529-6220 jmartin@marcoislandutilities.com

• Vice Chair Fred Gleim (239) 216-4773 fredlicious@gmail.com • Secretary-Treasurer Jack Green (239) 825-5058 jgreen@marcoislandutilities.com

• Secretary-Treasurer-Elect Bill Smith (941) 204-3038 Bets.6252@embarqmail.com

Region 9 • Director Jim Smith (386) 878-8976 jsmith@deltonafl.gov • Chair Glenn Whitcomb champ95@cfl.rr.com • Vice Chair (West) Jamie Hope hope2protectFLwaters@gmail.com

• Vice-Chair (East) Scott Ruland (386) 574-2181 sruland@deltonafl.gov • Secretary Frank Kelsey (386) 574-2181 esfm20x@hotmail.com • Treasurer Ron Cartwright (800) 330-1369 ron.cartwright@dumontchemicals.com

• Secretary-Treasurer-Elect Jeff Elder (386) 878-8977 jelder@deltonafl.gov

Region 10 • Director Mike Darrow (813) 506-6592 mdarrow@templeterrace.com • Chair Cindy Sammons (863) 701-1149 cindysammons@polk-county.net

• Vice Chair Alberto Montalvo amwastewater@yahoo.com • Secretary-Treasurer Katherine Kinloch (863) 678-4182, ext. 225 catloch3@verison.net • Secretary-Treasurer-Elect Damon Summers (863) 678-4182, ext. 294 dsummers@cityoflakewales.com

Region 11 • Director Thea Parslow (407) 246-4086 athena.parslow@cityoforlando.net

• Chair Mike Stephenson (407) 246-2213 • Vice Chair Dan Dashtaki (407) 246-2213

For additional information on officers and committee chairs, visit the Association website at http://www.fwpcoa.org. • Secretary-Treasurer Scott Stoll (407) 709-8808 wtrreg11@aol.com • Secretary-Treasurer-Elect John Nalencz (407) 599-3563

Region 12 • Director Gerry Schoonmaker Gerry.schoonmaker@gmail.com • Chair Patrick Murphy pmurphy@plantcitygov.com • Vice Chair John McRae Wolfe (813) 875-2486 jwolfe@pachydermmarketing.com

• Secretary-Treasurer David Guilmette davidguilmette6@aol.com

Region 13 • Director JM (Bud) Moody region.director13@gmail.com • Chair Stanley Young stanleyj65@hotmail.com • Vice Chair Cameron Young (386) 758-5453 region.vicechair13@gmail.com • Secretary Arnold Gibson (386) 466-3350 arnold@isgroup.net • Treasurer Linda Andrews (386) 758-5452 region.treasurer13@gmail.com

STANDING COMMITTEE CHAIRS AWARDS & CITATIONS Renee Moticker (954) 967-4230 rmoticker@yahoo.com CONSTITUTION AND RULES Tom King (321) 867-3042 TkingH20@aol.com CUSTOMER RELATIONS Norma Corso (941) 764.4508 Norma.Corso@charlottefl.com

DUES AND FEES Tom King (321) 867-3042 TkingH20@aol.com EDUCATION Art Saey (954) 630-4433 arthurs@oaklandparkfl.org ETHICS Odis Carter (850) 627-2089 odiscarter@tds.net HISTORICAL Al Monteleone almontele@embarqmail.com JOB PLACEMENT Joan Stokes (407) 293-9465 MEMBERSHIP Rim Bishop (561) 627-2900 Ext. 314 rbishop@sua.com POLICIES AND PROCEDURES David Clanton (386) 758-5452 theclantongang54@gmail.com PROGRAM AND SHORT COURSE Jim Smith (386) 878-8976 goodtogo@cfl.rr.com PUBLICITY Janet DeBiasio (727) 892-5640 Janet.Debiasio@stpete.org SYSTEMS OPERATORS Raymond Bordner H2oboy2@juno.com WEBSITE Walt Smyser webmaster@fwpcoa.org

SPECIAL COMMITTEE CHAIRS AUDIT Tom King (321) 867-3042 TkingH20@aol.com EXAM CONSULTANT Raymond Bordner h2oboy2@juno.com

FWRJ/FWRC Tom King (321) 867-3042 TkingH20@aol.com LEGISLATIVE David Clanton (386) 758-5452 theclantongang54@gnail.com NOMINATING Raymond Bordner H2oboy2@juno.com OPERATORS HELPING OPERATORS John Lang Jflang2012@gmail.com PAT ROBINSON SCHOLARSHIP Renee Moticker (954) 967-4230 rmoticker@yahoo.com SAFETY Peter M. Tyson (305) 295-2214 ptyson@fkaa.com

EDUCATION SUBCOMMITTEES BACKFLOW Glenn Whitcomb Champ95@cfl.rr.com CONTINUING EDUCATION Joseph Habraken jhabraken@tampabay.rr.com INDUSTRIAL PRETREATMENT Janet DeBiasio (727) 892-5640 Janet.Debiasio@stpete.org PLANT OPERATIONS Jamie Hope Hope2protectFLwaters@gmail.com

ADMINISTRATION EXECUTIVE DIRECTOR Tim McVeigh (954) 683-1432 tim.fwpcoa@comcast.net TRAINING COORDINATOR Shirley Reaves (321) 383-9690 training@fwpcoa.org WEBMASTER Walt Smyser webmaster@fwpcoa.org

FWRC/FWRJ APPOINTMENTS • Third-Year Trustee Jeff Poteet (239) 394-5595 jpoteet@marcoislandutilities.com

• Second-Year Trustee David Denny (386) 878-8100 ddenny@deltonafl.gov • First-Year Trustee David Clanton (386) 758-5452 theclantongang54@gmail.com • Member Rim Bishop (561) 627-2900, ext. 314 rbishop@sua.com • Member Tom King (321) 867-3042 TkingH20@aol.com • Member Al Monteleone almontele@embarqmail.com • Member Glenn Whitcomb champ95@cfl.rr.com

RECLAIMED WATER Scott Walden (407) 836-6865 scott.walden@ocfl.net STORMWATER Tom King (321) 867-3042 TkingH20@aol.com

Florida Water Resources Journal • January 2014

FWEA FOCUS

FWEA: Pausing to Give Thanks Greg Chomic President, FWEA

s I write this column we are entering the annual holiday season. We start the season by giving thanks for our blessings, followed by the celebration of Christmas joy and hope, and conclude with resolutions for the new year. I have many blessings for which I am thankful, but as I look back on the last quarter of 2013, I am particularly thankful for the generous spirit that is evident among FWEA leaders and members.

Florida Water Festival Fun! The Third Annual Florida Water Festival was held once again at Crane’s Roost Park in

Altamonte Springs last October 26. I’ve attended every festival, and I’m pleased to report that this year’s was the best ever! The Florida Water Festival continues to grow, thanks to Stacey Smich of CH2M HILL and her planning committee, the FWEA Public Communication and Outreach Committee, the festival sponsors, and the Central Florida Chapter members who volunteered to work, as well as those who attended the event. Please read the nice article about the festival in this issue of the magazine authored by festival volunteer Kevin Vickers of Kimley-Horn and Associates. If you have never attended the Florida Water Festival, I highly recommend that you plan to do so this year with your family and friends! It is a great opportunity to show thanks for the blessings of clean water that we all enjoy, but too often take for granted, and to educate everyone about how we produce clean water. The Florida Water Festival will return to Crane’s Roost in October; Stacey and her team already have several new ideas that will ensure

that this year’s festival will be bigger and better than ever! Our long-term goal for the festival in central Florida is to grow and improve each year, and for more festivals to be hosted in other areas of the state. This year, the West Coast Chapter has answered the call: it will host the first Florida Water Festival at Spa Beach Park in downtown St. Petersburg on March 22. Juan Oquendo of Gresham Smith and Partners, chair of the chapter’s Water Festival Planning Committee, is looking for volunteers and sponsors. If you are a member of the West Coast Chapter, or just want to help, I urge you to answer Juan’s call to service by volunteering, sponsoring the festival, and attending with your family and friends. Juan can be reached at 813-440-1413 or at juan_oquendo@gspnet.com. Mark your calendars now and visit the FWEA website often for updates!

Smooth Sailing Ahead I am thankful for the support of the central Florida wastewater community that made the first-ever technical seminar hosted by our new Wastewater Process Committee such a big success! The seminar, titled “Wastewater Treatment from Stem to Stern: Righting the Process Ship,” attracted a full house of 77 registrants at the Polk County Utilities offices near Winter Haven. Our thanks go out to Gary Fries, Polk County director of utilities and FWEA Utility Council board member, and his staff, who graciously offered the use of the county’s training room for our event. Attendees listened attentively to presentations on a variety of topics, ranging from raw sewage screening system design to unconventional approaches to effluent disinfection that minimize trihalomethane formation. Committee Chair Jody Barksdale of Gresham Smith and Partners reported that he learned a lot while planning his first seminar and the information will be used to make future seminars even better. Planning is currently underway for the second of this regional seminar series scheduled for May 15 in northeast Florida in cooperation with our First Coast Chapter. Later on in the fall, the seminar series moves to southeast Florida, with a program tailored to wastewater issues specific to that area of the state. Look for details of these seminars on the “Events and Conferences” page of the FWEA website, www.fwea.org.

January 2014 • Florida Water Resources Journal

First Coast Shootout This past fall, our chapters were busy hosting fun networking activities for our members and their guests, often in cooperation with members of our sister organizations. Notable among these events, our First Coast Chapter, led by Chapter Chair Tim Harley of St. Johns County, teamed up with FSAWWA Region II to host the first annual Sporting Clay Shoot on November 12. After going over basic gun safety, 44 shooters (some who had never shot a gun before) split up in teams of four to compete for trophies for first- through thirdplace team scores and top individual scores. The top team score of 272 was garnered by the CH2M HILL team of Floyd Register, Barry Stewart, Mike Dykes, and Gordon Gruhn. Reese Comer, with Momberg & Comer Construction Services LLC, won top individual honors with a score of 74 out of a possible 100. Tim says that he was very pleased with the first-year turnout for this event and the feedback from participants was very positive; it will only get bigger and better as more people find out about it. The Sporting Clay Shoot promises to be another fun joint annual networking event, along with the Don Maurer Putting Tournament held on the 18-hole natural grass putting greens at the World Golf Hall of Fame, and the Annual Golf Tournament, which our First Coast Chapter members enjoy along with FSAWWA Region II members. As mentioned earlier in this column, on May 15, the First Coast Chapter teams up with the FWEA Wastewater Process Committee to host the next regional Wastewater Process Seminar. The seminar will be held during the day, followed later in the afternoon by what has been called the best networking event in the state: the Don Maurer Putting Tournament. I would like to thank Tim Harley and his First Coast Chapter steering committee for the fine job they are doing for our members in northeast Florida!

tions System Committee has the answer for you. On January 21-23, the committee is hosting the complete NASSCO certification for pipeline, manhole, and lateral assessment: Pipeline Assessment and Certification Program (16 hours), and Manhole and Lateral Assessment and Certification Program (8 hours). All manuals, test materials and processing, break refreshments, and lunch each day are included in the $950 registration fee. Class size is limited. Unfortunately, due to NASSCO requirements, the registration deadline was Dec. 13, 2013. But if you are interested in taking this training at a later date, keep checking the FWEA website for an encore of this training event later in the year! On January 30, the FWEA Integrated Water Resources Committee will host a fullday seminar: “Sustainable Solutions Utilities are Implementing for Integrated Water Resources.” The program is packed with practical integrated water quality planning solutions that have been successfully implemented by utilities in central Florida. The high-quality program is headlined by Thomas Frick, Florida Department of Environmental Protection division director of environmental assessment and restoration, and David Childs of Hopping, Green and Sams, who serves the

FWEA Utility Council as its primary council. They will provide timely updates on regulatory issues, including the status of the numeric nutrient criteria regulations. Other speakers include noted experts Mark McNeal of ASRus, Steve McIntyre of Parsons Brinkerhoff, Michael Schmidt of CDM Smith, and Scott Lee of AECOM; the utility perspective will be offered by Flip Mellinger of Marion County Utilities, Chris Rader of Altamonte Springs Utilities, and Robert Elmquist of Apopka Utilities. The seminar is a great value at the $75 member rate. It will be held at Second Harvest Food Bank’s spacious new conference facility in Orlando, which has plenty of free parking. Please visit the FWEA “Calendar of Events” or the “Conferences and Events” tabs on the FWEA website for all the details, and to register. Remember, if you are not a FWEA member, you can join online and then register at the FWEA member rate and save $50. Both CEUs and PDHs will be provided! In conclusion I would like to say a big THANK YOU! for your support of FWEA professional development and networking events. Please know that we are resolved to continue to earn your support by developing and offering members outstanding value for your membership investment.

Our New Year’s Resolution As Florida’s go-to association for environmental water quality professionals, our resolution for the new year is to continue to work hard for our members by hosting high-value seminars and networking events around the state, and we are starting the year off right with two outstanding training events in the month of January. If you are a collection system technician and have been hoping to take the NASSCO PACP/MACP/LACP certification training, but could not justify the high cost of travel to an out-of-state training venue, the FWEA CollecFlorida Water Resources Journal • January 2014

FWEA CHAPTER CORNER Welcome to the FWEA Chapter Corner! Each month, the Public Relations Committee of the Florida Water Environment Association hosts this article to celebrate the success of recent association chapter activities and inform members of upcoming events. To have information included for your chapter, send the details via email to Suzanne Mechler at MechlerSE@cdm.com.

Suzanne Mechler

Southwest Chapter Update Patricia DiPiero

12th Annual Golf Tournament The Southwest Chapter of the Florida Water Environment Association joined forces on September 27 with Region 5 of the Florida Section of the American Water Works Association for the 12th Annual Golf Tournament held at the Heritage Palms Golf and Country Club in Fort Myers. The picture-perfect day drew 72 golfers and 12 hole sponsors. The tournament raised over $3,000 and the proceeds were divided among the Roy Likins Scholarship, Norm Casey Scholarship, and the Florida Gulf Coast University Endowed Fund, which was established in 2005 by the chapter and the Florida Gulf Coast University Foundation. The scholarship was awarded on November 22 during the annual FGCU President’s Scholarship Luncheon. This year’s recipient, a civil engineering student, received $700.

The Southwest Chapter would like to thank all of those who participated in another successful golf tournament, with all the proceeds going to supporting our future water and wastewater professionals.

Sixth Annual Southwest Water and Wastewater Expo The 6th Annual Southwest Water and Wastewater Expo held last September allowed local water professionals and vendors to come together for a day of training and learning. The Expo provided continuing education units (CEUs) and professional development hours (PDHs) to over 100 registered students through five training sessions. Over 60 vendors were on hand to display the latest equipment and services for the water and wastewater industry. The Expo also provides great opportunities for utilities and other water-related companies to highlight local projects and services.

Southwest Chapter Holiday Social attendees Craig Pajer and Kirk Martin.

January 2014 • Florida Water Resources Journal

Florida Gulf Coast University Student Chapter Events The chapter continues to foster a great relationship with the FGCU Student Chapter. Throughout the school year, the chapter provides “Lunch and Learn” sessions for the students. This is a great opportunity for them to hear what is currently happening in the utility, learn about real-world job experiences, and have an opportunity to ask questions, all while having a free lunch. The students continue to participate in the Student Design Competition and our quarterly dinner meetings. Patricia DiPiero is legislative and compliance programs manager with Lee County Utilities in Fort Myers.

Other Social attendees were Ron Cavalieri and Marc Lean.

Florida Water Resources Journal â&#x20AC;˘ January 2014

January 2014 â&#x20AC;˘ Florida Water Resources Journal

Florida Water Resources Journal â&#x20AC;˘ January 2014

January 2014 â&#x20AC;˘ Florida Water Resources Journal

Florida Water Resources Journal â&#x20AC;˘ January 2014

January 2014 â&#x20AC;˘ Florida Water Resources Journal

FSAWWA SPEAKING OUT

New Year, New Chair, New Mentoring Program Carl R. Larrabee Jr. Chair, FSAWWA

ach year brings the FSAWWA a new slate of officers, a new dynamic, and a new set of challenges and opportunities to face. All of the many resources of the section, including its finances, will be engaged: past chairs, officers, support staff, and most importantly, its members. And all of these members are associated for a primary purpose: provide safe, reliable, affordable drinking water to their customers, the citizens of the state of Florida. This coming year, as your new chair, I’d like to share some ideas we have and actions we’re taking to serve this purpose.

Ambassador Program As with many associations, membership in FSAWWA has slipped during the economic slowdown. This trend must reverse. During the term of our Past Chair Jason Parrillo, the Ambassador Program was established under the leadership of our current Chair-Elect Mark Lehigh to provide outreach, primarily to util-

ities, regarding their level of participation in our section. Ambassadors have been selected, assigned to various utilities, and are currently being equipped with statistics and membership benefit materials. As the new year begins, calendars will fill up with face-to-face meetings between utility officials and section ambassadors. I issue a call out to all of our members: If you think your utility would benefit from a personal meeting with our ambassadors, please contact Mark Lehigh (lehighm@HillsboroughCounty.org) or Executive Director Peggy Guingona (fsawwa@gmail.com). They will assure that a timely meeting is scheduled with your utility.

Mentoring Program Now for the latest initiative: the FSAWWA Mentoring Program. Our section has identified a shortcoming that hurts membership recruitment and retention: too much time elapses between a member signing up and then becoming fully integrated into the association. Those members who don’t “connect” will “disconnect.” Recruiting members must be followed by a strong retention effort. Opportunities abound for new members to participate in ways that make a difference.

But connecting new members with those opportunities hasn’t been effective for all of our new members. A mentoring of new members by “veterans” was chosen as the best way to facilitate that effort. At the section’s strategic planning retreat this past October, 18 members (nine pairs connected as mentor/mentee) began the inaugural mentoring class. They’re talking, emailing, meeting face-to-face, eating together, and most importantly, they’re sharing knowledge, wisdom, and contacts. Guidelines for effective pairings and ideas for personal contacts are being assembled for an expanded program beginning this year. Sign-up forms for participation will be posted on the section’s website this month. Please give serious consideration to your participation as a mentor or mentee. Also, please feel free to contact me anytime this year. I would enjoy talking with any of our members or prospective members. Your section is as open as ever to new ideas to better serve our primary purpose: supplying safe, reliable, and affordable drinking water to the citizens of Florida! Last but not least—Jason Parrillo, you provided great leadership this last year. Thank you so much for your exemplary service to the section!

Taste Test to be Held at Florida Water Resour ces Conference The Best Tasting Drinking Water Contest is held annually by the regions within the Florida Section of the American Water Works Association (FSAWWA). The winners from these regional events are invited to participate in the statewide competition held in the spring at the Florida Water Resources Conference to determine the state’s best drinking water. The winner from the state contest is then invited to compete in the international event held at the AWWA Annual Conference and Exposition (ACE) in June.

All of these events help to build excitement and pride within the drinking water industry. They offer the potential for outreach to the public through media coverage of the contests, which also highlights the diversity of members who serve as judges and represent a cross-section of the entire water community. Traditionally, water utilities have been considered the “silent service,” providing an essential commodity—water—every day to their customers, in a usually continuous, uninterrupted manner. With today’s

ever-increasing public involvement, it is important to show that water utilities perform “technical miracles” every day by providing safe drinking water, maintaining the public’s trust and confidence. These events give the industry the opportunity to showcase its life-giving product. For more information about the regional and state contests, contact the section’s Public Affairs Council chair, Jennifer McElroy at mcelroy@gru.com, or Peggy Guingona, FSAWWA executive director at fsawwa@gmail.com.

Florida Water Resources Journal • January 2014

F W R J

Removing One of the “I’s” from Infiltration and Inflow Frederick Bloetscher, Dominic F. Orlando, and Ronnie Navarro he vast majority of water and sewer utilities in the United States are operated by municipal governments or local authorities. Local officials want to develop water and sanitary sewage systems that will meet the water and sewerage needs of the areas served by their utilities, ensure that existing and future utility systems are constructed, operated, and managed at a reasonable cost to the users without outside subsidies, and develop a system that is compatible with the area’s future growth. The initial goal of the Clean Water Act was to clean up the nation’s rivers and streams through the removal of untreated industrial and domestic wastewaters, which means that the top priority of wastewater systems was to provide a level of service meeting state and federal regulatory requirements, as well as the demands and expectations of their customers. The initial focus was on treatment plants, but once they were constructed, the priority shifted slightly to combined systems, which had a propensity to overflow (sanitary sewer overflows, or SSOs) during rain events, due to hydraulic limitations of the piping systems in combined sewers that were mostly in the North-

east and Midwest. Because the ratepayers bear the ultimate cost of service, utilities usually try to develop plans that will permit the utility to meet its priorities at an affordable and stable cost for the long term. These plans include long-term maintenance and repair of the piping systems; however, by their very nature (buried pipes and protected facilities that are out of the public view), water and sewer utility operations are not in the forefront in the minds of elected officials, local government management, or finance personnel. Water and sewer services are viewed as basic services, which are not as “glamorous” as more visible municipal services, such as industrial parks, community revitalization areas, public buildings, landscaping, public parks, or recreational opportunities that gain positive community headlines. Because of the technical nature of water and sewer systems, they are not well understood by local government officials. The lack of obvious problems or critical failures may lead local officials to believe the water and sewer infrastructure to be “ok” as it is (Bloetscher, 2011). As a result, these piping systems may be neglected over time.

Figure 1. Coal tar epoxy on the outside of a manhole.

January 2014 • Florida Water Resources Journal

Frederick Bloetscher, Ph.D., P.E., LEED-AP, DWRE, is an associate professor at Florida Atlantic University in Boca Raton and president of Public Utility Management and Planning Services Inc. Dominic F. Orlando, P.E., is public services director, and Ronnie Navarro, P.E., is a city engineer with City of Dania Beach.

Regulatory focus under the Clean Water Act resulted in the development of the capacity, management, operation, and maintenance (CMOM) program. This program is intended to ensure that sewer collection systems, pumps, and wet wells are properly maintained in an effort to eliminate sanitary sewer overflows from plugged pipes or lack of pumping capacity in lift stations. With CMOM, pipe is inventoried and cleaning and repair work is tracked. Maintenance logs are also required for lift stations. Since keeping excess flows down benefits the utility financially, correction of leaks and infiltration should be priority projects. By reducing infiltration and inflows into the gravity wastewater system, the utility can reduce costs at wastewater treatment plants. The gravity collection system consists of the gravity pipes, manholes, service lines, and cleanouts. Collection system piping throughout North America prior to 1980 was predominately vitrified clay, with polyvinyl chloride (PVC) being a major pipe material after that. Vitrified clay pipe has been used for well over one hundred years because the pipe is resistant to deterioration from virtually all chemicals that could be in the water, and from various soil conditions. It has a long service life when installed correctly and left undisturbed. However, vitrified clay pipe is brittle, so settling from improper pipe bedding, unstable soil, surface vibrations, or freezing can cause the pipe to crack. Older vitrified clay pipe has short joints—as small as 2 ft prior to 1920, and 6 to 10 ft prior to 1960. Field joints were made prior to 1920, and even later. The joints were sealed with cement and Continued on page 32

Continued from page 30 cloth “diapers” wrapped around the joint. However, concrete is not waterproof and will crack with time. The combination results in piping with many joints, each of which has the potential to leak. Temperature differences between the warm wastewater and cooler soils can cause the exterior pipe surface to be damp. The dampness encourages tree roots to migrate to, and wrap around, the pipe. Where cracks occur, roots will enter the pipe. Over the long term, the pipe will become broken and damaged from the roots, joint seals, and vibrations, and in colder climates, from freezing. When the pipe is submerged, like it is in most of Florida, the pipe will constantly leak;

this is termed “infiltration.” Infiltration increases the base flow and will often be indicated by low-strength wastewater during routine tests. However, it generally does not lead to peak flows. As costs to treat and pump wastewater have risen, much of the focus has been on dealing with removal of infiltration; one step in this process is sealing manholes. Manholes are traditionally precast concrete or brick, with brick being the method of choice until the 1960s. Brick manholes suffer from the same problems as vitrified clay sewer lines: the grout is not waterproof so it can leak significant amounts of groundwater. Precast concrete manholes resolve part of this problem, but concrete is not impervious either.

While elastomeric or bituminous seals are placed between successive manhole rings, the concrete is still exposed. Many utilities will require the exterior of the manholes to have a coal-tar or epoxy covering, which helps to keep water out (see Figure 1). Lining the interior is of some value, but not nearly as much as coating the outside prior to backfill. The major focus to remove infiltration has been, and continues to be, oriented to lining gravity pipe, which includes a significant amount of televising to find leaks. Televising the sewer system and sealing and lining sections where leaks are noted is common; however, many miles of videotape show virtually nothing, but with significant money spent. Part of this is because “infiltration” and “inflow” are not the same, and storm events do not highlight infiltration nearly as much as inflow. The U. S. Environmental Protection Agency (EPA) has established infiltration criteria depending on the footage of collection sewer in an area as follows:

Table 1. EPA Infiltration Allowance (Bloetscher, 2011)

Figure 2. Indication of inflow to the sewer system. (Bloetscher, 2011)

Sewage Footage (ft.)

Allowance Range (gpd/in-mile)

> 100,000 50,000-100,000 1,000-50,000

2,000-3,000 3,000-5,000 5,000-8,000

The criteria in Table 1 are used as a primary indicator for the assessment and classification of collection system infiltration, but it should be noted that, for even large systems, the criteria may indicate 35 percent infiltration in the total wastewater flow, and it fails to separate inflow.

Separating Inflow and Infiltration

Figure 3. Identification of inflow, infiltration, and base flow in a sewer system flow hydrograph.

January 2014 • Florida Water Resources Journal

Where there are peaks in wastewater flows that match rainfall, inflow would appear to be a more likely candidate for the cause of the peaks than infiltration from pipes that are constantly under the water table. Storms highlight the need to reduce inflow into the collection system so as not to overwhelm the piping system hydraulically, causing plant damage or sewage overflows into streets because inflow results from a direct connection between the sewer system and the surface. The removal or accidental breaking of a cleanout, unsealed manhole covers, laterals on private property, connected gutters or storm ponds, damaged chimneys from paving roads, or cracking of

the pipe may be a significant source of inflow to the system, which can be identified easily during storm events. Figure 2 shows a typical graph of rainfall versus flow for a given utility. The peaking that correlates with the rainfall is inflow, not infiltration, since infiltration is part of the base flow that creeps upward with time. Infiltration looks much like the base flow. For the utility in Figure 3, the average daily water is just over 2.05 mil gal per day (mgd), but the wastewater flow is over 3.8 mgd, indicating nearly 1.2 mgd of infiltration. When plant operators and engineers see peaks in flows after rain events, this is not indicative of groundwater infiltration; it is indicative of active connections from the surface to the piping system, which is inflow. The good news is that simple, low-tech methods can be used to detect inflow, which should be the precursor to any infiltration investigation.

Resolving the Inflow Problem Ongoing testing of the influent and monitoring of the lift stations by a utility provides a measure to determine whether inappropriate amounts of inflow are going to the wastewater plant. This testing can take a variety of forms, such as a review of lift station run times, followed by analyses of the influent wastewater quality. Low-strength wastewater is an indication of both infiltration and inflow problems, and low-strength wastewater during dry periods is infiltration; during wet events, it could be both.

Resoling Inflow Resolving the inflow problems is straightforward, and from a utility standpoint, the more benefit that can be gained per dollar spent, the better. Lessening potential regulatory actions from overflows is also a risky issue to address. Both indicate that inflow should be the first priority, followed by traditional televising and lining projects. Inflow can be resolved in an orderly fashion. The following outlines a basic program for inflow detection and correction for any utility system. The order of implementation is important, and pursuing all steps in order will resolve the majority of inflow issues, while permitting the utility to target the specific areas where infiltration is a problem. The program as outlined also minimizes unneeded videotaping of the collection system and permits more dollars to go toward fixing problems. The first step is inspection of all sanitary sewer manholes for damage, leakage, or

Figure 4. Installation procedure. (photos: USSI Inc.)

other problems, which, while seeming obvious, is often not the case. The manhole inspection should include documentation of condition, global positioning system (GPS) location, and some form of numbering if not currently available. Use of a geographic information system (GIS) database, with ties

to photographic data, is a useful addition. Most manholes have limited condition issues, but where the bench or walls are in poor condition, they should be repaired with an impregnating resin. Deterioration may be an indication of wastewater quality concerns, Continued on page 34

Florida Water Resources Journal â&#x20AC;˘ January 2014

Continued from page 33 requiring the addition of chemicals to reduce the impact of hydrogen sulfide. Next is the repair and sealing of chimneys in all manholes to reduce inflow from the street during flooding events. The chimney includes the ring, cement extensions, lift rings, brick, or cement used to raise the manhole ring. Manhole covers are often disturbed during paving or as a result of traffic.

Temperature, vibration, and traffic can break the seal between the steel ring and concrete. The crack between the ring and cover can leak a lot of water, as demonstrated by a Miami-Dade County test conducted several years ago (Miami-Dade 2010). The intent of the chimney seal is to prevent inflow from the area beneath the rim of the manhole, but above the cone. To properly seal the system, a flexible polymer based coating, installed in

accordance with the following procedure, should be used (see Figure 4): 1. Remove all loose mortar, concrete brick, or other materials, as they will interfere with seal performance and adhesion. 2. High-pressure sandblast the chimney and ring to create a dry, clean surface, free from dust and moisture. 3. Apply a primer coat to the clean chimney material in accordance with manufacturer instructions. 4. Allow the primer to cure as specified by the manufacturer prior to application of lining material. 5. Apply the lining material on top of the primer in accordance with manufacturer instructions. The lining material should be flexible but resistant to account for surface loading, temperature, and vibrational changes that create most chimney damage. 6. The primer and lining should have a finished, dry thickness greater than 120 mL. The following outlines a typical specification for the primer and seal:

Figure 5. Inflow defender manhole rain dish showing installed dish, and both polycarbonate and polyethylene versions. Note the ribs and depth of dish that improves long-term strength. Note polycarbonate is required for newer, 30- or 48-in. manhole covers. Texas has mandated 30-in. holes for new manholes. Only stainless steel and polycarbonate are available in the larger sizes.

Figure 6. Smoke Test. (photo: USSI Inc.)

January 2014 â&#x20AC;˘ Florida Water Resources Journal

Primer coat Specific gravity > 1.0 >90 percent solids as measured by ASTM D2369 Elongation 650 +/- 50 as measured by ASTM D412 Adhesive strength > 700 psi on steel or concrete as measured by Eclometer 109 Tensile strength = 3200 +/- 50 psi as measured by ASTM D412 Tear resistance =325 +/- 10 psi as measured by ASTM D624 Nonflammable as measured by ASTM D93 in a Pensky-Martens closed cup Temperature range -65 to 200 F Minimal water absorption capacity (<0.5 percent) Top Coat Specific gravity > 1.0 >99 percent solids as measured by ASTM D2369 As applied, solids greater than 70 percent Ultimate elongation equal to or greater than 850 percent +/- 50 as measured by ASTM D412 Elongation as applied equal to or greater than 335 percent +/- 10 as measured by ASTM D412 Adhesive strength > 700 psi on steel or concrete as measured by Eclometer 109 Tensile strength = 2000 +/- 50 psi as measured by ASTM D412 Continued on page 36

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Continued from page 34 Tear resistance =300 +/- 10 psi as measured by ASTM D624 Nonflammable as measured by ASTM D93 in a Pensky-Martens closed cup Temperature range -65 to 200 F Minimal water absorption capacity (<0.5 percent) Shore A hardness equal to 75 +/- 5 as measured by ASTM 2240

Figure 7. LDL Plug Design. (photo: USSI Inc.)

Figure 8. Areas where further infiltration investigation via televising is needed (only 15 percent of the system).

January 2014 â&#x20AC;˘ Florida Water Resources Journal

The next step is to put dishes into the manholes. One might think that only manholes in low lying areas get water into them, but surprisingly, every manhole dish, even one that is properly installed, has water in it. Hence, it must be assumed that all manholes leak water between the rim and the cover. Most collection system workers are familiar with dishes at the bottom of the manhole, where they are of limited use. This is because those dishes deform when filled with water or are constructed is a manner that allows them to be knocked in when the cover is flipped. The solution is a deeper dish with reinforcing ribs and a gasket. Figure 5 shows two examples (note the man standing in the upside-down dish). The dishes shown are made of a polycarbonate (shiny) and a polyethylene copolymer material that meet the requirements of Underwriters Laboratories (UL) Standard 94-HB and American Society for Testing and Materials (ASTM) specification Prime HDPE 250 to be suitable for atmospheres found in manholes. The polymer-based dishes eliminate the dissimilar metals issues with stainless steel dishes and are available at a lower cost. The key is the appropriate reinforcing to prevent dishes from dropping into the manhole. The gasket seal should be made of a closed-cell neoprene material with pressure sensitive adhesive on one side for adhering to the dish body, and be a minimum of Â˝ in. wide and 0.125 in. thick. As the standards for manholes gets larger (Texas rules are now 30 in.), only stainless steel and polycarbonate are available options. To ensure the manhole dishes meet the system needs, a test can be run to evaluate dishes. Miami-Dade County tested dishes using the following procedure three times each, where the average drain time was used in the calculations of inflow rates (Miami Dade, 2010): Apply 2 ft of head pressure to the MH frame and cover. Document the time it takes the water to drain through the opening between the frame and the cover.

The volume of the water in gal and the drain time is used to calculate an inflow rate. The following scenarios were tested (no dish, standard dish, reinforced dish with gasket): No insert inflow rate: 5.45 gal per minute (gpm) Standard insert inflow rate: 0.72 gpm Inflow Defender Manhole Inflow DishÂŽ (reinforced with gasket): 0.002 gpm Miami-Dade County chose the latter dish for obvious reasons. Similar tests should be done in other locales. Once the manholes are sealed, smoke testing can identify obvious surface connections (see Figure 6). The normal protocol for smoke testing will identify broken or missing cleanout caps, surface breaks on public and private property, connection of gutters to the sewer system, and stormwater connections. All should be documented via photograph, by associated address, and public or private location. The public openings at cleanouts can be corrected immediately using utility funds; the contractor can include this cost to make immediate repairs in the bid documents. However, if the cleanout is broken, it may indicate mower or vehicle damage that can occur again. If missing, the resident may be using the cleanout to drain the yard (more common than realized). In either case, the collection system needs to be protected. Utility Sealing Services Inc. (USSI) in Venice developed a solution, called the LDL plug, consisting of the following (see Figure 7): A molded, one-piece, synthetic urethane polymer material plug body designed to align and seal the cleanout. Inner seal of the plug shall consist of a PVC material fabricated with an internal tapered, beveled seat, with a thickness of 0.187 in. and overall height of 1.25 in. Embedded retrieval hasp and hardware should protrude at least 1 in. above the plug body, have a thickness of 0.187 in., and have hardware molded into the plug body using corrosion-resistant material to allow removal by utility crews from the surface. Plug has embedded steel to permit surface detection by a metal detector. Installation in the vertical riser of the cleanout is undertaken as follows: Remove cleanout cap (broken or otherwise). Wipe all cleanouts to remove soil and moisture from the interior of cleanout

Figure 9. Comparison of flows in December of 2009 at Dania Beach and a neighboring system. Note the big spike after the rainfall that was not present on the system with limited rain (13 in. increased flows by over 2 mgd).

Figure 10. Comparison of flows in October of 2011 at Dania Beach and a neighboring system. Note the spikes on the same neighboring system versus the lack of large spikes in Dania Beach. The gradual upticks are likely groundwater levels creating infiltration.For Dania Beach, the 5-in. storm raised flows less than 0.5 mgd. stack as they would interfere with the plug. Scuff the interior of stack with emery cloth.

Swab interior scuffed area with PVC cleaner. Swab exterior of inner seal ring of plug with PVC cleaner. Continued on page 38

Florida Water Resources Journal â&#x20AC;˘ January 2014

Continued from page 37 Apply PVC glue to interior walls of cleanout and exterior of inner seal ring of plug. Slide inner seal ring into appropriate point in cleanout, align with depth gauge installation tool, and twist to glue in place. Notices should then be sent to property owners with documentation of the inflow connections to their properties. This is sometimes the most difficult part of the program due to political considerations, but it is necessary. The final step is a low-flow investigation, which is intended to target the infiltration piece of the problem. Such an event will take several days and must be planned to determine the priority manhole to start with, and the sequencing. Based on a projected plan, the following protocol is based on where there is and isn’t flow: Open the manholes. Inspect them for flow. Determine if the flow is significant. If flow exists, open consecutive manholes upstream to determine where flow is derived. Generally, a 2-in.-wide bead of water is a limit of “significant” infiltration. Figure 8 is an example from Dania Beach. After 20 years of no investigation, only 15 percent of the pipe segments indicated infiltration leakage. This reduced the

televising and lining portion of its lining program by over $1 million, which more than paid for the inflow reduction project.

Results So, the question is: What is the cost, and how successful is this type of protocol? The City of Dania Beach pursued this program for its inflow correction to identify where infiltration efforts should be concentrated. The service area consisted of 800 manholes, and the total cost was $480,000, which included fixing 25 manholes, sealing all 800 manholes and dishes, repairing 200 public inflow openings, identifying 300 private connections, and conducting two smoke test events and one midnight run. In the past, the City of Dania Beach incurred substantial peaks from “normal” rainfall events. Figure 10 shows the City of Dania Beach and a neighboring community in December 2009, when the rainfall on one day was over 13 in. (although it was only 2.5 in. the neighboring community). Significant flooding on the east side of Dania Beach lasted three weeks, in part because the sewer system was sealed on public property, but openings remained on private property. Figure 11 shows October 2011, when 13 in. of rain fell during the month, including 3.5and 5-in. storms a week apart. While the data is given on a daily basis, it is clear that the Dania Beach system did not incur the sustained peaks of the past, although infil-

Figure 11. Comparison of Cooper City lift station area flows before and after the G7 program in one of four lift station basins (typical).

January 2014 • Florida Water Resources Journal

tration remains an issue (currently under contract). The cost to treat wastewater averages $3.50/1000 gal. The City of Dania Beach has estimated it saved 200,000 gal per day (gpd) over the course of a year as a result of its inflow correction effort, while substantially reducing its peaks; this is a savings of over $250,000 per year. Payback is under two years. In addition, Figure 10 shows the limited areas for televising to correct infiltration, the next phase of Dania Beach’s program. Only 15 percent of the system had infiltration identified, and this is 20 years after the last “I and I” correction effort. Full television inspection would have revealed nothing in 85 percent of the system. An estimated 800,000 gpm of inflow existed in the yellow pipes, which will yield substantial additional savings. This effort has shown that investment in infiltration and inflow reduction by the utility should provide confidence that it will see reductions in inflow to the wastewater treatment plant, and reductions in its operating costs. Most specifics can be discovered when daily flow information is compared in a given area before and after inflow repairs are completed. Cooper City, located in Broward County, decided to pursue a pilot inflow reduction program in spring 2012. Data for 2011 and 2010 were compared to determine how different the results were. Figure 11 shows a comparison of pump times and rainfall (x 1000 for ease of graphical comparison) for 2011 and summer 2012. The graphic does not show conclusive data, but breaking the information down is more illuminating. Figure 12 shows the same lift station with rainfall versus pump run time in 2011. This was done for three lift stations in the area, addressed with inflow correction for both 2011 and 2012. More informative would be a graph of rainfall versus pump time for specific storm events; the concept is to determine if there is less run time post-inflow correction. The results will show, on a line sloped for a relationship, a greater slope, meaning more pump run time for a given rain event. The data were combined for the lift station basins (52 to 54) to find similar storm events each year; only these values were compared. Figures 13 to 15 show a comparison of specific rain events versus pump run time. In each case, the slope of the line through the 2011 values is substantially above the slope of the 2012 rain events. For lift station 52 and 53, the pump run times do not change significantly, regardless of rain totals, indicating

Figure 12. Rainfall (x 1000) versus pump run time. Correlation for run time and rainfall was 0.5.

Figure 14. Comparison of rain events (in.) versus pump run times in 2011 and 2012 for Cooper City Lift Station 53. The slope of the lines show that the inflow correction substantially reduced inflow. The 2012 graph shows virtually no effect of rainfall on run times.

that for this basin, most of the inflow has been removed (Figures 13 and 14). In the lift station 54 basin, the 2012 line is nearly flat, and there does not appear to have been as much inflow in this basin in 2011. Still a change in the slope is noted (Figure 15). The results of the two case studies shows that inflow is separate from infiltration, the peaks in flows are inflow and can be removed relatively easily, the costs are reasonable, and the solutions relatively simple. Getting the

Figure 13. Comparison of rain events (in.) versus pump run times in 2011 and 2012 for Cooper City Lift Station 52. The slope of the lines show that the inflow correction substantially reduced inflow. The 2012 graph shows virtually no effect of rainfall on run times.

Figure 15. Comparison of rain events (in.) versus pump run times in 2011 and 2012 for Cooper City Lift Station 54. The slope of the lines show that the inflow correction reduced inflow.

right technology and specifications is important. Correcting inflow helps utilities target the specific lines where infiltration correction is needed, negating the televising and cleaning of miles of pipe where no damage is found. This saves the utility money as well. Overall, correcting inflow first will likely reduce the overall cost of infiltration and inflow correction, and bring a greater return on invested dollars in the form of reduced flows.

References â&#x20AC;˘ Bloetscher, Frederick (2011), Management for Water and Wastewater Operators, America Water Works Association; Denver, Colo.

Florida Water Resources Journal â&#x20AC;˘ January 2014

F W R J

Incorporation of High-Level Ultraviolet Disinfection to Meet Stringent Effluent Discharge Disinfection Byproducts Limits Lynn Spivey, Sean Chaparro, Steve Schaefer, and William Harrington he South Cross Bayou Water Reclamation Facility (SCBWRF) in Pinellas County was originally constructed in 1960 with a 15-mil-gal-per-day (mgd) average capacity. A 12-mgd expansion and other improvements were implemented in the 1970s and 1980s. In 2004, the County completed a project to expand the facility to an average flow of 33 mgd, with a peak hourly flow of 66 mgd. Effluent from the facility is currently disinfected with chlorine gas, and on average, 20 to 30 percent of the effluent is discharged via surface water to the Joe’s Creek outfall, a Class III water body, with the remaining used for beneficial reuse. In 2010, the County entered into a consent order with the Florida Department of En-

vironmental Protection (FDEP) that required the surface water discharge from the facility via the Joe’s Creek outfall to meet regulatory limits by June 30, 2013 (subsequently amended to Sept. 30, 2014), for trihalomethanes (THMs), which are disinfection byproducts (DBPs) of chlorination. Specifically, water discharged to Joe’s Creek must contain less than 34 micrograms per liter (µg/L) of chlorodibromomethane (CDBM), and less than 22 µg/L of dichlorobromomethane (DCBM). Both limits are running annual averages (RAA) based on grab samples collected monthly. These limits do not apply to the reuse and land application systems. In order to meet these limitations, a new advanced disinfection system consisting of

January 2014 • Florida Water Resources Journal

Lynn Spivey is principal engineering consultant and Sean Chaparro, P.E., is senior environmental engineer with ARCADIS-US Inc. in Tampa. Steve Schaefer, P.E., is principal engineer with Parsons Water & Infrastructure Inc. in Tampa. William Harrington, P.E., is engineering support services supervisor— planning and design section, with Pinellas County.

high-level ultraviolet (UV) disinfection for surface water discharges was planned and designed. Due to a tight consent order compliContinued on page 42

Florida Water Resources Journal â&#x20AC;˘ January 2014

Continued from page 40 ance schedule, only prevalidated UV systems for reuse applications were considered, and a prepurchase of the selected UV system was completed to ensure that the tight compliance schedule could be met. The new UV system is currently under construction and will be retrofitted in the facility’s existing automatic backwash filter basins. This article discusses the methodology and results of the evaluation completed to confirm the required UV system capacity and the assessment of the major available prevalidated

UV systems that will meet the high-level disinfection requirements of the facility. To minimize costs, a split stream treatment approach was used, where the UV system would only treat a portion of the flow and then be blended with the chlorinated/dechlorinated stream prior to discharge. Various UV system capacities were assessed to determine the “optimum” UV system capacity that will meet disinfection requirements at a UV transmittance (UVT) below the minimum prevalidated level, and ensure that the blended stream can comply with the running annual average surface water dis-

Figure 1. Average Hourly UVT Value

Figure 2. Cumulative Frequency of UVT – Average Hourly Data

January 2014 • Florida Water Resources Journal

charge DBP limits. Provisions included in the contract documents to verify and confirm that the UV system will meet disinfection requirements at a design UVT below the minimum prevalidated levels are also presented.

Establishing the Design Ultraviolet Transmittance For a UV system, the design UV dose is an indicator of the amount of pathogen reduction that this system will achieve under the most challenging design conditions. During validation testing, specific UV doses are determined, which represent the UV dose distribution of a specific UV system and account for the inherent variability of UV intensity and hydraulics. The National Water Research Institute (NWRI) has developed guidelines to establish the ability of commercial UV systems to deliver specific UV doses in a standardized way (Second Edition of the NWRI Guidelines for Drinking Water and Reuse, or 2003 NWRI Guidelines). Most UV equipment manufacturers validate their UV systems in general accordance with these guidelines. The UVT is by far the most important water quality parameter used for sizing UV systems. The UVT is a measurement of the UV light’s ability to penetrate the water, which is necessary to inactivate pathogens. Lower UVT values signify that UV light will travel shorter distances before attenuation; this means that more UV light will be required in order to achieve a given design UV dose. As such, selection of a UVT design value is critical due to its impact on disinfection efficacy, system size, footprint, capital costs, and operation and maintenance (O&M) costs. Regarding reuse applications that require high-level UV disinfection, the FDEP has adopted by reference the 2003 NWRI guidelines. For high-level disinfection of granular media filtration effluent, these guidelines recommend the use of a minimum design dose of 100 mJ/cm2 and UVT254 value of 55 percent, or alternatively, a design UVT254 value corresponding to the 10th percentile of a set of data collected at least three times a day over a minimum period of six months. In accordance with these guidelines, the SCBWRF installed an on-line UVT analyzer and started collecting real-time UVT data in the fall of 2010. Each hourly value was averaged by the plant supervisory control and data acquisition (SCADA) system logic from the on-line UVT analyzer continuous output signal; 24 hourly average UVT254 values were thus generated each day. Figure 1 shows a chronological graph of the average hourly UVT254 values. As seen since the start of the UVT254 collection program, there has been a general downward trend, with occasional prolonged

UVT dips, followed by recoveries. The UVT values have ranged between 40 and 75 percent throughout the monitoring period. This data set was subsequently used to determine a design UVT254 value based on the 10th percentile approach as outlined in the 2003 NWRI guidelines. The data set of average hourly UVT254 values from Oct. 1, 2010, to Nov. 18, 2011, was ranked in ascending order relative to the entire data set range, creating a cumulative frequency graph. Figure 2 is the result of this analysis. As seen in the figure, the 10th percentile value recommended for design by the 2003 NWRI guidelines was 51 percent. This design UVT is lower than what would be anticipated from a facility with tertiary treatment and lower than the minimum 55 percent UVT that has been prevalidated for any highlevel UV disinfection system. A detailed review of operating data found correlations between the low UVT254 values and rainfall, plant flow, and effluent total organic carbon (TOC). The general relationship among these parameters is that rainfall causes high flows to enter the plant, in turn inducing an increase in TOC, with an associated decrease in UVT254. Only a slight correlation between lower UVT254 and higher effluent nitrate was observed. The levels of TOC and nitrate may be a direct consequence of an upset within the plant process at times of high flow. A broad-level process review and operational shadowing of the SCBWRF was subsequently completed to identify potential opportunities to enhance the UVT through basic process changes within the existing treatment scheme. The process review and operational shadowing identified a number of process changes that may help improve treatment performance and increase UVT. However, identified changes were not used to change the design UVT of 51 percent, but instead were recommended for implementation as a long-term strategy to optimize system performance, increase UVT, and reduce operating costs of the UV system when operational. To assure the FDEP and Pinellas County that the UV system can meet disinfection requirements at a low design UVT of 51 percent, the selected UV manufacturer was required as part of its contract agreement to: Provide a performance guarantee based on permitted effluent limits. Complete site-specific computational fluid dynamics (CFD) modeling of the systems and providing detailed calculations and backup documentation demonstrating how the UV system would be sized to meet the design UVT of 51 percent based on validation data at 55 percent (there is a systematic, validated Continued on page 44 Florida Water Resources Journal â&#x20AC;˘ January 2014

Continued from page 43 relationship between UVT and UV dose). Maintain conservative safety factors throughout design (validate with MS2, a conservative challenge organism; design for worst-case scenario, such as lamp aging and fouling factors; and provide a redundant

UV bank in each channel). Successfully complete 21-day performance testing at startup. Performance testing will include checkpoint bioassay testing and fecal coliform reduction testing to confirm that the correct UV dose is applied and disinfection requirements are met. Flow-split testing

Figure 3. Year-Round UV System Operation DBP Concentrations Versus UV System Capacity

Figure 4. Seasonal UV System Operation DBP Concentrations Versus UV System Capacity

January 2014 â&#x20AC;˘ Florida Water Resources Journal

will also be required to verify that an even flow-split is achieved among UV channels.

Determining the Required Ultraviolet System Capacity The required UV system capacity for the SCBWRF was evaluated based on several factors: DBP effluent limits. Historical DBP concentrations (October 2009 through 2011), which best represent operational conditions for the future UV system. The DBP data prior to this was not included due to plant improvements made in mid-2009, which successfully reduced and consistently maintained DBP levels. Historical surface water discharge (SWD) flows (October 2010 through November 2011). Historical rainfall and reclaimed system demand (seasonal). System cost. As previously indicated, the UV system was not sized to handle the entire permitted surface water discharge flow (20 mgd). To minimize costs, a split stream treatment approach was used, where the UV system would only treat a portion of the surface water discharge flow. The tertiary-treated effluent would be split into two streams: one would be chlorinated/dechlorinated, while the other stream would be disinfected using UV. The UV-disinfected effluent would have a DBP concentration of 0 mg/L and would be blended with the chlorinated/dechlorinated tertiary effluent stream downstream of dechlorination before discharge to Joe's Creek. To determine the optimal UV system capacity, a range of flows were evaluated that would meet the annual average DBP limits upon blending prior to surface water discharge. The following two overall operational protocols were evaluated: 1. Year-round operation. Operating the UV system year round for a selected UV system capacity. Flows within the UV system capacity will be discharged to Joeâ&#x20AC;&#x2122;s Creek with zero DBPs. 2. Seasonal operation. Operating the UV system on a seasonal basis for a selected UV system capacity. For this scenario, the UV system would operate during periods of the year when the UVT is at or above a selected UVT value. During periods when the UVT is below the set point, the UV system would not operate and the entire SWD flow would be disinfected by chlorination prior to discharge. To determine the period where the UV system would not be operational, the data set was assessed for months that showed the UVT below the design value. For

the data set of October 2010 through November 2011, it was determined that the UV system would not be operational during the months of July, August, and September.

In order to stay below 80 percent of the annual average DBP permit limits, a capacity of 10 mgd is required for year-round treatment. For seasonal treatment, a capacity of 13

mgd is required. The increase for seasonal treatment is due to the higher influent and lower reclaimed flows at this time. It should be Continued on page 46

Due to the overall variability and limited amount of data available, future flows were estimated by assuming maximum monthly surface water flows based on historical data. The DBP concentrations were estimated by assuming the 90th percentile historical concentrations. The target concentrations for each permitted DBP are 80 percent of the current permit limits. Thus, for the various UV system capacities presented in the analysis, and for surface water discharge (SWD) flows greater than the UV system size, the blended DBP concentration was determined using following equation: 90th Percentile DBP Concentrations (µg/L): Chlorinated Flow (mgd) * Average 90th percentile DBP concentration for data set (µg/L) SWD (mgd) The resulting capacity analysis for both the year-round operation and seasonal operation based on the analysis described are shown in Figure 3 and Figure 4.

Figure 5. Estimated DBP Concentrations for an 8 mgd UV System

Florida Water Resources Journal • January 2014

Continued from page 45 noted that this particular seasonal treatment analysis had high rainfall and corresponding high SWD for the months of July through September, but could vary considerably depending on the weather (rainfall) in southwest Florida. In addition, DBP formation is influenced by temperature, and during the summer, when the UV system is not operational, the potential for DBP formation is the highest due to the high temperatures. Therefore, yearround treatment may not always be more effective than seasonal operation. A UV system

size of 10 mgd would provide the flexibility to utilize either operational option to meet the DBP regulatory effluent limits, depending on the rainfall and amount of time the UV system is not operational. There is potential that operating on a seasonal basis may result in DBPs closer to the permitted limits. To better illustrate the seasonal variation and implications throughout the entire year for the various system capacities, graphs were prepared to show the estimated daily surface water discharge DBP concentrations, the running annual DBP concentrations, SWD, and

UVT based on the calculations and assumptions outlined . Figures 5 through 7 show the modeled DBP concentrations (based on the information and assumptions presented above) for year-long operation for UV system capacities of 8, 10, and 12 mgd. As shown in the graphs, the number of days with DBP concentrations above 80 percent of the limits increases as the system size decreases. The RAA for the estimated DBP concentrations are below the permit target for the entire year for the 10- and 12-mgd capacities. This analysis shows that a UV system capacity above 10 mgd may be too conservative, since only a few days per year are projected above the limits. The results also show that a UV system capacity of 8 mgd will result in projected DCBM and RAA concentrations above the target limit during the high flow period. Based on these results, the UV system was designed for a capacity of 10 mgd, which should provide sufficient treatment capacity to ensure that effluent DBP concentrations of the blended flow stay within the DBP effluent limits. The UV system design also provides the flexibility necessary to increase system capacity in the future, if needed or desired by the County, by providing room for additional UV channels and required equipment.

Comparison of Prevalidated Ultraviolet Systems

Figure 6. Estimated DBP Concentrations for a 10 mgd UV System

Figure 7. Estimated DBP Concentrations for an 12 mgd UV System

January 2014 â&#x20AC;˘ Florida Water Resources Journal

A detailed review of the major prevalidated UV systems available for high-level disinfection of the SWD at the SCBWRF was conducted to identify and compare the main system characteristics, design criteria, and estimated capital and O&M costs for each of the UV systems. The UV systems evaluated include systems from Trojan, Ozonia, and WEDECO, all of which have been accepted by the California Department of Public Health (CDPH) and FDEP for high-level disinfection applications. Calgon, another major UV manufacturer, did not participate in this initial assessment. The lamp orientation of the UV system (i.e., vertical, Ozonia versus horizontal, Trojan, and WEDECO) was an important consideration in evaluating the UV systems, since it has a significant impact on the required structural modifications to retrofit the modules within the existing filters, maintenance requirements, and overall capital and O&M costs. Table 1 summarizes and compares the key design criteria, features, and maintenance requirements of the Trojan, Ozonia, and WEDECO UV systems evaluated. Table 2 compares the capital, annual O&M, and presContinued on page 48

Table 1. Comparison of Ultraviolet Systems

Florida Water Resources Journal â&#x20AC;˘ January 2014

Table 2. Ultraviolet System Cost Comparison Matrix Continued from page 46 ent-worth costs for each of the UV system alternatives.

Selected Ultraviolet System Based on the technical, maintenance, and cost evaluation of the various UV systems, discussions with Pinellas County technical and maintenance staff, and site visits to various operating UV disinfection systems run by other municipalities in Florida; the selected UV system for the SCBWRF was the vertical array UV system Aquaray 40HO, manufactured by Ozonia. This system was selected due to the following distinguishing characteristics: Greater ability to manage fluctuations in liquid level due to the vertical lamp array configuration. Faster lamp startup time due to the type of lamp used. Ease of lamp replacement since modules do not need to be removed to replace lamps. Ease of downturn and flexibility of operation because of the ability of the system to turn off individual rows of lamps within a module and provide faster ramp up capabilities. Lower life cycle costs.

January 2014 â&#x20AC;˘ Florida Water Resources Journal

Operators: Take the CEU Challenge! Members of the Florida Water & Pollution Control Association (FWPCOA) may earn continuing education units through the CEU Challenge! Answer the questions published on this page, based on the technical articles in this month’s issue. Circle the letter of each correct answer. There is only one correct answer to each question! Answer 80 percent of the questions on any article correctly to earn 0.1 CEU for your license. Retests are available. This month’s editorial theme is

Wastewater Treatment . Look above each set of questions to see if it is for water operators (DW), distribution system operators (DS), or wastewater operators (WW). Mail the completed page (or a photocopy) to: Florida Environmental Professionals Training, P.O. Box 33119, Palm Beach Gardens, FL 33420-3119. Enclose $15 for each set of questions you choose to answer (make checks payable to FWPCOA). You MUST be an FWPCOA member before you can submit your answers!

___________________________________________ SUBSCRIBER NAME (please print)

Article 1 ________________________________________ LICENSE NUMBER for Which CEUs Should Be Awarded

Article 2 ________________________________________ LICENSE NUMBER for Which CEUs Should Be Awarded

If paying by credit card, fax to (561) 625-4858 providing the following information:

Earn CEUs by answering questions from previous Journal issues!

___________________________________________

Contact FWPCOA at membership@fwpcoa.org or at 561-840-0340. Articles from past issues can be viewed on the Journal website, www.fwrj.com.

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Incorporation of High-Level Ultraviolet Disinfection to Meet Stringent Effluent Discharge Disinfection Byproducts Limits

Separate or Combined Sidestream Treatment: That Is the Question

Lynn Spivey, Sean Chapparro, Steve Schaefer, and William Harrington

(Article 2: CEU = 0.1 WW}

(Article 1: CEU = 0.1 WW)

1. Real-time ultraviolet light transmittance data obtained from a 2010 South Cross Bayou Water Reclamation Facility (SCBWRF) test yielded a recommended ____ UVT254 design criteria. a. 55 percent b. 51 percent c. 10 mJ/cm2 d. 100 mJ/cm2 2. After extensive review, which type of ultraviolet (UV) lamp array was selected for this application? a. Vertical b. Horizontal c. Circumferential d. Diagonal 3. The Florida Department of Environmental Protection (FDEP) consent order governing this facility’s discharge to land application systems limits dichlorobromomethane to a. 80 micrograms per liter. b. 34 micrograms per liter. c. 20 micrograms per liter. d. This compound is not limited. 4. Two of the three evaluated UV systems used _______ type lamps. a. mercury vapor b. sodium vapor c. high output amalgam d. laser 5. In order to stay below 80 percdent of the annual average disinfection byproduct permit limits, a UV treatment capacity of ____ mgd is required for seasonal treatment at this facility. a. 10 b. 13 c. 15 d. 20

Rod Reardon

1. In 2010, municipal wastewater treatment facilities consumed about ______ of United States electrical demand. a. 4,000 kWh b. 25 million kWh c. 1.5 percent d. 60 percent 2. ___________ bacteria are autotrophic organisms capable of converting a mixture of ammonia and nitrite directly to nitrogen gas. a. Nitrifying b. Denitrifying c. Annamox d. Aerobic 3. Which of the following is identified as a “separate” sidestream treatment process? a. InNitri b. MAUREEN c. BAR d. BABE 4. Of the case study sites discussed, which facility has achieved energy self-sufficiency? a. Sjolunda b. Strass c. Robert W. Hite d. 26th Ward 5. The seeding of a mainstream process with ammonia oxidizing/nitrite oxidizing bacteria grown in a sidestream reactor is called a. fermentation. b. bioaugmentation. c. aerobic biosupplementation. d. anaerobic biosupplementation.

Florida Water Resources Journal • January 2014

2013-2014 FSAWWA BOARD OF GOVERNORS Executive Committee

Trustees

Carl R. Larrabee Jr., P.E. Chair St. Johns River Water Management District P.O. Box 1429 Palatka, Florida 32178 P: (386) 329-4222 E: clarrabee@sjrwmd.com

Fred Bloetscher Trustee Florida Atlantic University P.O. Box 221890 Hollywood, Florida 33022-1890 P: (239) 250-2423 F: (954) 925-2692 E: h2o_man@bellsouth.net

Jason P.F. Parrillo, P.E. Past Chair Hydra Service Inc. 111 Maritime Drive Sanford, Florida 32771 P: (407) 330-3456 F: (407) 330-3404 E: jason@hydraservice.net Mark D. Lehigh Chair-Elect Hillsborough County Water Resource Services 332 N. Falkenburg Road Tampa, Florida 33619 P: (813) 272-5977, ext. 43270 F: (813) 635-8152 E: lehighm@hillsboroughcounty.org Kimberly A. Kunihiro Vice Chair Orange County Utilities 9124 Curry Ford Road Orlando, Florida 32825 P: (407) 254-9555 F: (407) 254-9558 E: kim.kunihiro@ocfl.net William G. Young Secretary St. Johns County Utilities 1205 State Road 16 St. Augustine, Florida 32084 P: (904) 209-2703 F: (904) 209-2702 E: byoung@sjcfl.us Grace M. Johns, Ph.D. Treasurer Hazen and Sawyer P.C. 4000 Hollywood Blvd., Suite 750N Hollywood, Florida 33021 P: (954) 987-0066 F: (954) 987-2949 E: gjohns@hazenandsawyer.com Matt Alvarez, P.E. Outgoing General Policy Director (June 2014) CH2M HILL Inc. 201 Alhambra Circle, Suite 600 Coral Gables, Florida 33134 P: (305) 443-6401 F: (305) 443-8856 E: matt.alvarez@ch2m.com

Florida Section AWWA By Region

Jeffrey W. Nash, P.E. Outgoing Association Director (June 2014) CDM Smith 2301 Maitland Center Parkway, Suite 300 Maitland, Florida 32751 P: (407) 718-9956 E: nashjw@cdmsmith.com Jacqueline W. Torbert Incoming Association Director (June 2014) Orange County Utilities Water Division 9150 Curry Ford Road, 3rd Floor Orlando, Florida 32825 P: (407) 254-9850 F: (407) 254-9848 E: jacqueline.torbert@ocfl.net Matt Alvarez, P.E. Alternate Association Director (June 2014) CH2M HILL Inc. 201 Alhambra Circle, Suite 600 Coral Gables, Florida 33134 P: (305) 443-6401 F: (305) 443-8856 E: matt.alvarez@ch2m.com Ana Maria Gonzalez, P.E. Incoming General Policy Director (June 2014) Hazen and Sawyer P.C. 4000 Hollywood Blvd., Suite 750N Hollywood, Florida 33021 P: (954) 987-0066 F: (954) 987-2949 E: agonzalez@hazenandsawyer.com Kim Kowalski Treasurer-Elect Wager Company of Florida Inc. 1611 Silk Tree Circle Sanford, Florida 32773 P: (407) 834-4667 F: (407) 831-0091 E: kkowalski@wagerco.com

January 2014 â&#x20AC;˘ Florida Water Resources Journal

Christine S. Ellenberger Trustee Jacobs Engineering 245 Riverside Avenue, Suite 300 Jacksonville, Florida 32202 P: (904) 636-5432, ext. 127 F: (904) 636-5433 E: christine.ellenberger@jacobs.com Mark Kelly Trustee Garney Construction 370 E Crown Point Road Winter Garden, Florida 34787 P: (321) 221-2833 F: (407) 287-8777 E: mkelly@garney.com Dave Slonena Trustee Pinellas County Utilities 14 S. Ft. Harrison Avenue Clearwater, Florida 33756 P: (727) 464-4441 F: (727) 464-3595 E: dslonena@co.pinellas.fl.us Tyler Tedcastle Trustee CDM Smith 8381 Dix Ellis Trail, Suite 400 Jacksonville, Florida 32256 P: (904) 527-6721 F: (904) 519-7090 E: tedcastletj@cdmsmith.com

Council Chairs Christopher Jarrett Administrative Council Chair American Cast Iron Pipe Company 300 Primera Blvd., Suite 240 Lake Mary, Florida 32746-2144 P: (407) 804-1420 F: (407) 804-1201 E: cjarrett@american-usa.com Richard Hewitt Contractors Council Chair PCL Construction Inc. 3810 Northdale Blvd., Suite 200 Tampa, Florida 33624-1873 P: (813) 264-9500 F: (813) 961-1576 E: rhewitt@pcl.com

Todd Lewis Manufacturers/Associates Council Chair U.S. Pipe & Foundry LLC 14580 Saint Georges Hill Drive Orlando, FL 32828 P: (407) 592-1175 F: (877) 505-1570 E: tlewis@USPIPE.com Steve Soltau Operators Council Chair Pinellas County Dept. of Environment & Infrastructure 3655 Keller Circle Tarpon Springs, Florida 34688-7813 P: (727) 453-6990 F: (727) 453-6962 E: ssoltau@co.pinellas.fl.us

Ronald Cavalieri Region V Chair (Southwest Florida) AECOM 4415 Metro Parkway, Suite 404 Fort Myers, Florida 33916-9402 P: (239) 278-7996 F: (239) 278-0913 E: ronald.cavalieri@aecom.com

Jennifer McElroy Public Affairs Council Chair Gainesville Regional Utilities P.O. Box 147117 Station A-136 Gainesville, Florida 32614 P: (352) 393-1291 F: (352) 334-2752 E: mcelroyja@gru.com

Mike Bailey, P.E. Region VI Chair (Southeast Florida) Cooper City Utilities 11791 SW 49th Street Cooper City, Florida 33330-4447 P: (954) 434-5519 F: (954) 680-3159 E: mbailey@coopercityfl.org

Roberto Denis Technical & Education Council Chair Liquid Solutions Group LLC 369 Whitcomb Drive Geneva, Florida 32732 P: (407) 349-3900 F: (407) 349-3935 E: rdenis@liquidsolutionsgroup.com

Juan Aceituno Region VII Chair (South Florida) CH2M HILL Inc. 201 Alhambra Circle, Suite 600 Coral Gables, Florida 33134 P: (305) 443-6401 F: (305) 443-8856 E: juan.aceituno@ch2m.com

Patrick Lehman Utility Council Chair Peace River Manasota Regional Water Supply Authority 9415 Town Center Parkway Lakewood Ranch, Florida 34202 P: (941) 316-1776 F: (941) 316-1772 E: plehman@regionalwater.org

Brad Macek Region VIII Chair (East Central Florida) City of Port St. Lucie 6001 Silver Oak Drive Fort Pierce, Florida 34982-3225 P: (772) 461-0263 F: (772) 461-6405 E: bmacek@cityofpsl.com

Region Chairs Edward A. Bettinger, RS, MS Region I Chair (North Central Florida) DOH â&#x20AC;&#x201C; Bureau of Water Programs 4052 Bald Cypress Way, Bin C-22 Tallahassee, Florida 32399 P: (850) 245-4240 ext. 2696 F: (850) 921-0298 E: ed_bettinger@doh.state.fl.us Andrew May Region II Chair (Northeast Florida) JEA 21 W. Church Street Jacksonville, Florida 32202-3158 P: (904) 665-4510 F: (904) 665-8099 E: mayar@jea.com

Kristen Sealey Region XI Chair (North Florida) Golder Associates Inc. 6026 N.W. 1st Place Gainesville, Florida 32607 P: (352) 336-5600 F: (352) 336-6603 E: kristen.sealey@golder.com

Emilie Moore Region IV Chair (West Central Florida) Tetra Tech 400 N. Ashley Avenue, Suite 2600 Tampa, Florida 33602 P: (727) 709-1705 F: (813) 282-7893 E: emilie.moore@tetratech.com

Donald E. Hamm Region XII Chair (Central Florida Panhandle) Bay County Utility Services 3410 Transmitter Road Panama City, Florida 32404 P: (850) 747-5703 F: (850) 872-4805 E: dhamm@baycountyfl.gov

Section Staff Peggy Guingona Executive Director Florida Section AWWA 1300 Ninth Street, B-124 Saint Cloud, Florida 34769 P: (407) 957-8449 F: (407) 957-8415 E: fsawwa@gmail.com Casey Cumiskey Membership Specialist/Training Coordinator Florida Section AWWA 1300 Ninth Street, B-124 Saint Cloud, Florida 34769 P: (407) 957-8447 F: (407) 957-8415 E: fsawwa.casey@gmail.com Donna Metherall Training Coordinator Florida Section AWWA 1300 Ninth Street, B-124 Saint Cloud, Florida 34769 P: (407) 957-8443 F: (407) 957-8415 E: fsawwa.donna@gmail.com

Monica Autrey Region IX Chair (West Florida Panhandle) Destin Water Users Inc. P.O. Box 308 Destin Florida 32540-0308 P: (850) 837-6146 F: (850) 837-0465 E: mautrey@dwuinc.com Richard Anderson Interim Region X Chair (West Central Florida) Peace River Manasota Regional Water Supply Authority 8998 S.W. CR 769 Arcadia, Florida 34269 P: (863) 993-4565 E: randerson@regionalwater.org

Jenny Arguello Staff Assistant Florida Section AWWA 1300 Ninth Street, B-124 Saint Cloud, Florida 34769 P: (407) 957-8448 F: (407) 957-8415 E: fsawwa.jenny@gmail.com

Greg Taylor, P.E. Region III Chair (Central Florida) CDM Smith 2301 Maitland Center Parkway, Suite 300 Maitland, Florida 32751 P: (407) 660-2552, ext. 6329 F: (407) 875-1161 E: taylorgd@cdmsmith.com

Florida Water Resources Journal â&#x20AC;˘ January 2014

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Separate or Combined Sidestream Treatment: That is the Question Rod Reardon n 2010, municipal wastewater treatment facilities consumed about 25 bil kWh of electricity. Individual facilities use anywhere from 1,000 to 4,000 kWh per mil gal (MG) treated, depending on the level of treatment and the overall efficiency of power use. This represents about 1.5 percent of the total power demand in the United States. About half of the power demand at a wastewater treatment facility is for aeration (10–20 kWh/population equivalent [p.e.]/yr). Further, nitrification constitutes about half the power required for aeration, with the actual fraction depending on the chemical oxygen demand/total Kjeldahl nitrogen (COD/TKN) ratio in the influent to the aeration tank. Thus, the need for nitrification consumes roughly 6 bil kWh per year. While up to 60 percent of this incremental demand can be offset by incorporating a high degree of denitrification into the treatment process, the remainder still represents a huge power demand. Implementation of new techniques for reducing the power requirement for nitrogen removal could significantly lower power demands at municipal wastewater treatment facilities. While implementation of nitrogen removal at municipal wastewater treatment plants provides significant public health and environmental benefits, nitrogen removal processes also require more electrical power to operate and release more greenhouse gases than a comparable secondary treatment process. A standard Modified Ludzack-Ettinger (MLE) process in Florida using an oxidation ditch with aerobic holding or digestion of the waste sludge will consume about 3,000 kWh per mg of water recovered and release over 4.7 lbs of CO2 per lb of nitrogen removed. By implementing more efficient aeration and anaerobic digestion, the power demand for this same MLE process can be reduced about 10 to 20 percent, not counting the energy that can be recovered from the biogas generated in the digestion process. Despite the attractiveness of anaerobic digestion from an energy perspective, the destruction of volatile solids during digestion releases significant amounts of nitrogen, which is typically recycled into the mainstream treatment process. This recycle load increases the process air, alkalinity, and carbon requirements for nitrogen removal in

proportion to the mass of ammonia recycled. The magnitude of nitrogen recycle loads from anaerobic digestion depends on the use of primary treatment, the importing of sludge from other facilities, the type of sludge stabilization employed, and the degree of volatile solids destruction achieved. Depending on the plant configuration and dewatering schedule, recycling of sidestream ammonia can result in diurnal spikes in effluent ammonia or total nitrogen (TN). Using a typical Florida wastewater treatment plant with conventional nitrogen removal and mesophilic anaerobic digestion as an example, ammonia recycle will typically be between 10 and 15 percent of the influent nitrogen load. However, with the addition of sludge from other facilities and the use of advanced digestion processes, the recycle load can approach 50 percent of the influent.

Overview of Nitrogen Cycle Significant developments have occurred over the last ten to fifteen years that have improved the understanding of the nitrogen cycle and opened new opportunities for managing high ammonia sidestreams. One of the most significant advancements in the understanding of the biology of nitrogen transformations is the discovery of a group of microorganisms in the phylum Planctomycetes; these have become better known as anammox bacteria (Anaerobic Ammonia Oxidation). Anammox bacteria are autotrophic organisms capable of converting a mixture of ammonia and nitrite directly to nitrogen gas. It is now recognized that previously known organisms can transform nitrogen by multiple metabolic pathways, more microorganisms are significantly involved in nitrogen transformations, and the interactions among groups of bacteria are more complex. The following is a brief summary of the three main approaches to using conventional and innovative biology for nitrification and denitrification of sidestreams: 1. Conventional Nitrification and Denitrification – Conventional biological nitrogen removal is a multistep process in which a combination of autotrophic and heterotrophic bacteria sequentially converts ammonia to nitrogen gas according to the

January 2014 • Florida Water Resources Journal

Rod Reardon is wastewater process engineer with Carollo Engineers in Orlando.

following equations: a. Ammonia is oxidized to nitrite (NO2-) by ammonia oxidizing bacteria (AOBs): NH4+ + 1.5 O2 → NO2- + H2O + 2 H+ b. Nitrite is converted to nitrate by nitrite oxidizing bacteria (NOBs): NO2− + 0.5 O2 → NO3− c. Nitrate is converted to nitrogen gas by ordinary heterotrophic bacteria (OHOs) 6NO3− + 5CH3OH→ 3N2 + 5 CO2 + 7H2O + 6OH− According to these equations for conventional biological nitrogen removal processes, the need to remove ammonia affects oxygen demand and alkalinity. In addition, the relatively slow growth rate of nitrifiers AOBs and NOBs increases the required sludge inventory, but has relatively little effect on sludge production, aside from the decreased yield associated with longer sludge retention time (SRT). Denitrification imposes additional requirements on biological nutrient removal (BNR) processes, including the need to control dissolved oxygen (DO) input, and for additional anoxic sludge inventory and sufficient carbon relative to the nitrogen to be reduced. The stoichiometric oxygen requirement for conventional nitrification is 1.5·32/14= 3.43 mg O2/mg N for ammonia oxidation and 0.5·32/14 = 1.14 mg O2/mg N for nitrite oxidation. The first reaction consumes alkalinity. The required COD:N ratio for denitrification is 2.86. Including sludge production, the required COD:N ratio is about 4, depending on the carbon source. 2. Shortcut Nitrification and Denitrification – Researchers at the Technical University of Delft discovered that the conventional nitrification process could be stopped halfway; that is, after the formation of nitrite. They gave this first application of partial nitrification (or nitritation) the name Sharon (Single reactor system for High Ammonium ReContinued on page 54

FWPCOA TRAINING CALENDAR SCHEDULE YOUR CLASS TODAY! JANUARY 7........Backflow Recert..........................................Lady Lake ............$85/115 13-16........Backflow Tester ..........................................Deltona ................$375/405 13-16........Backflow Tester ..........................................St. Petersburg ......$375/405 24........Backflow Tester Recert*** ........................Deltona ................$85/115 27-31........Wastewater Collection C, B ......................Deltona ................$325/355 27-31........Wastewater Collection A ..........................Orlando ..............$225/255

FEBRUARY 3-7........Water Distribution Level 3, 2 ..................Deltona ................$275/305 10-12........Backflow Repair ........................................Deltona ................$275/305 28........Backflow Tester Recert*** ........................Deltona ................$85/115

MARCH 4........Backflow Recert..........................................Lady Lake ............$85/115 3-6........Backflow Tester ..........................................St. Petersburg ......$375/405 24-28........SPRING STATE SHORT SCHOOL ............Ft. Pierce 28........Backflow Tester Recert*** ........................Deltona ................$85/115

APRIL 7-9........Backflow Repair ........................................St. Petersburg ......$275/305 21-24........Backflow Tester ..........................................Deltona ................$375/405 25........Backflow Tester Recert*** ........................Deltona ................$85/115

MAY 6........Backflow Recert..........................................Lady Lake ............$85/115 5-9........Wastewater Collection C, B ......................Deltona ................$325/355 12-15........Backflow Tester ..........................................St. Petersburg ......$375/405 19-21........Backflow Repair ........................................Deltona ................$275/305 23........Backflow Tester Recert*** ........................Deltona ................$85/115 Course registration forms are available at http://www.fwpcoa.org/forms.asp. For additional information on these courses or other training programs offered by the FWPCOA, please contact the FW&PCOA Training Office at (321) 383-9690 or training@fwpcoa.org. * Backflow recertification is also available the last day of Backflow Tester or Backflow Repair Classes with the exception of Deltona ** Evening classes

You are required to have your own calculator at state short schools and most other courses.

*** any retest given also Florida Water Resources Journal â&#x20AC;˘ January 2014

Continued from page 52 moval Over Nitrite). Stopping the nitrification reaction at a nitrite endpoint has also become known as shortcut nitrification denitrification (or shortcut NDN) since it bypasses or shortcuts the creation of nitrate. The comparable equations for shortcut NDN are as follows: d. Nitritation: NH4+ + 1.5 O2 → NO2− + 2 H2O + 2 H+ e. Denitritation: NO2− + 0.5 CH3OH−→ 0.5 N2 + 0.5 CO2 + 0.5 H2O + OH− The COD:N ratio is 1.72 for denitritation. Including sludge production, the required COD:N ratio is 2.4 (Mulder et al., 2006), depending on the carbon source, as compared to about 4 for conventional denitrification. Oxygen demand is reduced 25 percent and carbon demand is reduced 40 percent with shortcut NDN as compared to the conventional approach. 3. Partial Nitritation and Anammox – Since anammox bacteria require about a 50:50 mix of ammonia and nitrite, it is necessary to do nitritation in combination with anammox. Only about one-half of the ammonia needs to be converted to nitrite to create the right mix of feed. f. Nitritation: NH4+ + 1.5 O2 → NO2− + 2 H2O + 2 H+ g. Anammox: NH4+ + NO2− → N2 + 2 H2O h. Combined Sharon - Anammox NH4++ 0.75 O2 +HCO3– → 0.5 NH4+ + 0.5 NO2− + CO2+ 1.5 H2O The anammox reaction is autotrophic and

has low biomass yield (0.11-0.13 g VSS/g NH4+-N), but produces small amounts of NO3- (according to the molar ratio NO3/NH4+ = 0.26). Overall nitrogen removal in the combined (partial nitritationanammox) process requires less oxygen (1.9 kg O2/kg N instead of 4.6 kg O2/kg N), has no carbon source (instead of 2.4 – 4 kg COD/kg N), has low sludge production (0.08 instead of approximately 1 kg VSS/kg N), and reduces CO2 emission by more than 100 percent because the combined process uses less power and consumes CO2. Oxygen requirements, carbon demands, and alkalinity requirements resulting from use of these main groups of biological processes are summarized in Table 1.

Separate Methods of Sidestream Treatment A variety of treatment processes have been developed using both conventional and innovative biological concepts to treat high ammonia recycle streams. These sidestream treatment processes can be grouped according to the feed streams sent to the sidestream reactor. One group of processes keeps the sidestream separate and treats the sidestream by itself. The other group combines all or a portion of the return activated sludge (RAS) with the sidestream. Mixing RAS and the sidestream allows the use of some biological reactions (conventional, shortcut NDN, and bioaugmentation) and precludes others (anammox at this time). All but one of the separate methods relies on some sort of biomass retention to develop sufficient biomass for treatment. The exception is the Sharon process, which uses one or two

Table 1. Comparison of Biological Processes for Nitrogen Removal (from Jetten et al., 2002 & Ahn, 2006)

January 2014 • Florida Water Resources Journal

completely mixed stirred tank reactors without recycle (chemostats). By operating at a low hydraulic retention time (HRT), elevated temperature, and high ammonia concentration that results in the washout of NOBs, the Sharon process operates to a nitrite endpoint. With the Sharon process, the nitrites are typically removed by denitrification with methanol. Anammox bacteria grow much slower than nitrifiers, and their natural tendency to form relatively large granules with slightly greater density compared to normal activated sludge provides the basis for retaining these bacteria in the treatment process. Most separate sidestream treatment processes are well suited for using partial nitritation—anammox. However, two of the separate sidestream processes, short solids retention time (SRT) and Sharon, are not applicable for partial nitritation–anammox. The short SRT process, also known as InNitri™, is a sidestream-nitrifying activated sludge process with an aeration tank and clarifier, where waste sludge from the sidestream process is used to seed the mainstream process. There are no fullscale applications of the InNitri™ process. Understanding of the characteristics of anammox bacteria and the development of methods for using them for nitrogen removal has evolved over time through research done by numerous groups. Unfortunately, this has resulted in a large number of names and patents for essentially the same biology implemented in different reactor configurations with different control methods. A glossary of terms associated with sidestream treatment is provided at the end of this article. Current commercially available anammox systems for sidestream treatment include two sequencing batch reactor (SBR) processes, an upflow granular bed process, and a moving bed biofilm reactor (MBBR) process. Depending on the specific process, biomass retention is provided by gravity settling, cyclones, granular sludge, or a fixed film on MBBR media. The SBR processes use pH and DO control to maintain environmental conditions for the anammox bacteria. The MBBR process relies on the biofilm and control of the DO at low concentrations to wash the NOBs out of the process. Unlike the SBR/cyclone process, the MBBR process measures NH4, NO2, and NO3, and then uses the ratios of NO2/NH4 and NO3/NH4 to control aeration. Media fills are typically up to about 50 percent. The long startup times required for the first anammox processes are now avoided by seeding the reactors from other operating systems. The design volumetric loading rate for the MBBR process is about 1 kg N/m3/d. The granular sludge process can be loaded more heavily, up to

about 2 kg N/m3/d, but is reported to be less stable at the higher loading rates. Anammox reactions are inherently limited to a maximum ammonia removal of about 90 percent; however, they are capable of operating consistently at close to this limit. The advantages of the separate sidestream methods include the ability to use shortcut NDN and anammox bacteria, and to take advantage of the warm temperature and high ammonia concentration to operate at high biological reaction rates. Since the effluent is typically recycled to the mainstream process, higher ammonia concentration reactor effluent is acceptable and enables higher reaction rates. The main advantages to the separate sidestream treatment process using anammox are their low energy requirement and their ability to denitrify without carbon. Without the addition of an external carbon source, sludge production is lower. As mentioned, the reactor configurations vary, but all use proven rector designs. The main disadvantages of anammox processes are the slow growth rate of anammox bacteria, and the need to inhibit or wash NOBs out of the process. The slow growth rate of anammox bacteria requires seeding for reasonably quick startups, but there are now enough of the systems in existence so that obtaining seed sludge is feasible. As a result of the need to prevent the growth of NOBs, and to limit the buildup of nitrite concentrations, the process operating requirements are more complex, but the systems are readily automated. While the elevated temperatures of sidestreams are conducive to higher biological reaction rates, the sidestream reactor temperature must be controlled within the range of about 30–40ºC. Depending on the situation, this may require heating or cooling of the sidestream. Elevated concentrations of suspended solids in the sidestream can be detrimental to the performance of some separate processes, and possibly require pretreatment. Foaming has been reported at several separate sidestream treatment facilities, and scaling of the media in one MBBR reactor was a problem.

Combined Methods of Sidestream Treatment The combined sidestream processes are known by many names, including bioaugmentation regeneration (BAR); Aeration Tank No.3 (AT-3), named after work at the New York City 26th Ward Water Pollution Control Plant (WPCP); bioaugmentation batch enhanced (BABE); mainstream autotrophic recycle enabling enhanced N-removal (MAUREEN); and centrate and RAS reaeration basin (CaRRB).

The common feature to this group of processes is the mixing of a high ammonia sidestream with RAS in a sidestream reactor, resulting in subsequent return of the sidestream to the main process. The use of RAS adds alkalinity, lowers temperature, and increases the biomass concentration in the sidestream reactor. While conventional microbial processes do not provide the reduction in oxygen and carbon demands of shortcut NDN and anammox, when used in sidestream reactors they can provide substantial overall facility benefits. These include: Bioaugmentation of the mainstream process with nitrifiers resulting in a reduction in the aerobic SRT needed to maintain nitrification, along with elimination of the sudden washout of nitrifiers that can occur under wintertime conditions. Increased biomass inventory providing greater overall process stability and reduced effluent nitrogen, while enabling reduced solids loading to secondary clarifiers. Reduced carbon requirements and improved mainstream denitrification if denitrification is provided in the sidestream process. Ability to increase anoxic volume, at the expense of aerobic volume, to increase denitrification capacity in an existing plant. Reduced mixed liquor recycle rates if nitrite or nitrate is returned to a pre-aeration anoxic zone in the mainstream process. Potential to inhibit NOBs, thereby combining bioaugmentation with shortcut NDN.

Case Studies Robert W. Hite Treatment Facility, Denver (CaRRB) The Metro Wastewater Reclamation District (MWRD) in Denver operates the 220mgd Robert W. Hite Treatment Facility (Facility), which includes two separate primary and secondary complexes that are served by a common sludge complex, with mesophilic anaerobic digestion and centrifuge dewatering. In 2004, MWRD began planning improvements at the Facility to comply with tighter limits on ammonia, NOx, and phosphorus. The initial strategy in the north secondary complex was based on the addition of two new aeration basins and secondary clarifiers to supplement the existing 12 aeration basins and secondary clarifiers. As an alternative approach, the concept of combined sidestream treatment was evaluated and selected for implementation. The concept envisioned the construction of common CaRRBs instead of two new aeration basins and secondary clarifiers. Because bioaugmentation reduces the re-

quired SRT for nitrification in the mainstream process, the same nitrification performance can be maintained at lower bioreactor MLSS concentrations. This results in lower solids concentrations entering the secondary clarifiers, subsequently increasing clarification capacity. The original improvements strategy would have required two aeration basins with a combined volume of 4.1 MG and two 130-ft diameter secondary clarifiers. The CaRRB approach yielded approximately 20 percent more capacity than the original strategy with the construction of only 2.7 MG of centrate reaeration basins and without any new secondary clarifiers. This increased capacity resulted in a reduction in anticipated capital cost of approximately $17 million when compared to the original strategy. Combined sidestream treatment also allowed a reduction in the required mixed liquor return (MLR) pumping rate. Due to nitrification of centrate occurring in CaRRB, a significant amount of nitrate is generated and returned to the anoxic zones in the mainstream aeration basins. At MWRD, the CaRRB process generates approximately 6,000 to 8,000 ppd of nitrate as N that is fed to mainstream anoxic zones. This is equivalent to 70 to 100 mgd of MLR, or a reduction of 6 to 8 mgd per aeration basin. This allowed installation of smaller pumps and provides an energy cost savings of approximately $80,000 per year. Using combined sidestream treatment afforded several important advantages over the original improvements strategy, including increased capacity and performance at a lower cost, reduction in required mixed liquor return pumping, and improved denitrification. The CaRRB process has been in service since August 2009 and performance has exceeded expectations and confirmed the benefits offered by this process. Based on this success, CaRRB is being incorporated into the upgrades to the south secondary complex now under construction. 26th Ward Water Pollution Control Plant, New York City (Aeration Tank 3) Starting in 1992, as part of its program to eliminate the ocean disposal of sludge, New York City implemented a centralized sludge dewatering scheme where anaerobically digested sludge from the City’s 14 WPCPs are pumped or barged to eight centralized dewatering facilities. As a result, the nitrogen loads on the WPCPs that host the centralized dewatering facilities are increased by 30-50 percent from the increased centrate that is returned to the mainstream treatment processes. As centrate was identified as a significant source of nitrogen to the WPCPs, the City undertook investigations to find a feasible treatment method. Continued on page 56

Florida Water Resources Journal • January 2014

Continued from page 55 The New York City Department of Environmental Protection (DEP) investigations into centrate treatment began at the City’s 26th Ward WPCP, which has a central dewatering facility that receives sludge from up to four other WPCPs. This 85-mgd WPCP, located in Brooklyn and discharging to Jamaica Bay, uses a high-rate, four-pass step-feed-activated sludge process to treat average flows of about 70 mgd. Three step-feed tanks, each with a volume of 5 MG, provide aeration. Primary clarifier effluent is added to Passes B, C, and D of the step-feed aeration tanks, while RAS is added to Pass A. Anoxic zones are present at the beginning of Passes A, B, and C. After experimenting with several configurations, the DEP settled on a combined sidestream treatment process in which AT-3 was dedicated to centrate treatment. All of the centrate (about 1.3 mgd) is sent to AT-3, along with about 0.5-1.0 mgd of RAS (out of 10-15 mgd). The centrate averages about 750 mg/L ammonia with a soluble COD of 270 mg/L, a temperature of 28ºC, pH values of 8.3-8.5, and an alkalinity of 2,200 mg/L as CaCO3. The effluent from AT-3 is returned to the RAS channel whereby it enters Pass A of the other two aeration tanks. The AT-3 combined sidestream treatment process has proven to be very effective, and has provided significant benefits to the City. Bioaugmentation of the mainstream, high-rate, stepfeed BNR process (2-3 day SRT) at wintertime temperatures as low as 12ºC, allows stable yearround nitrogen removal with lower effluent TN concentrations. A calibrated process simulation model, based on extensive kinetic testing (Ramalingam, 2007), predicts that use of the AT-3 process is lowering the effluent TN during the winter from 16 mg/L to 11 mg/L, and model predictions are in line with current performance. In addition, the combination of high ammonia concentrations and high pH in the centrate tank combined with low DO concentrations in Pass A provides shortcut nitrification (inhibition of NOBs), resulted in a large reduction in process air requirements, and a reduction in carbon requirements in the step-feed BNR, which enhances denitrification. Estimates are that process airflow has been reduced from about 24,000 scfm to 16,000 scfm by using the AT-3 process.

Sjölunda WWTP, Malmo, Sweden (ANITA™ Mox) The Sjölunda Wastewater Treatment Plant provides wastewater treatment for Malmo, Sweden’s third largest city, and surrounding areas. With a design capacity of 550,000 p.e. (about 50 mgd), the plant currently treats

about 37 mgd, on average. The plant uses a combination of primary clarifiers with ferrous sulfate addition for phosphorus removal, highrate activated sludge (3-day SRT) with preanoxic zones, nitrifying trickling filters, and denitrifying MBBRs to meet effluent target concentrations of 0.3 mg/L total phosphorous (TP), on a monthly average, and 10 mg/L TN (annual average). Sludge treatment is provided by anaerobic digestion with centrifuge dewatering. The centrifuges operate about 50 percent of the time. When the plant was last upgraded in 1999 to provide nitrogen removal, an equalization tank and a SBR (0.5 mgal) with NaOH addition were added to remove about 1,500 lbs NH4-N/d from the centrate and lessen the ammonia load on the nitrifying trickling filters. The centrate nitrogen load is approximately 20 percent of the influent nitrogen load. The centrate flow at Sjölunda averages about 172,000 gal/day, with a mean ammonia concentration of 855 mg/L, a mean soluble COD concentration of 257 mg/L, and a mean total suspended solids concentration of 350 mg/L. Beginning in August 2010, a new MBBRbased, separate sidestream treatment process, named ANITA™Mox, started operation at Sjölunda. The new system treats about 30 percent of the centrate flow (the design N load equals 440 lb N/d), while the remainder is treated by the existing SBR. The full-scale ANITA™ Mox plant consists of four13,200-gal reactors with three different types of MBBR media (one with BiofilmChip M, two with K3, and one with AnoxK5), with media fills of about 50 percent. The specific surface areas for the three types of media are 500 m2/m3, 800 m2/m3, and 1200 m2/m3 respectively. Continuous aeration is provided by coarse bubble diffusers. DO is controlled to 0.5–1.5 mg/L. Neither temperature nor pH is controlled with pH, varying from 6.7-8.1, while reactor temperatures range from 22–33ºC. The system supplier, Veolia, has used this facility to demonstrate its BioFarm concept where media, with established anammox biomass, is used to seed and startup new facilities. Effluent typically contains about 100 mg/L of NH4 and NO3, and about 1 mg/L NO2. The design volumetric loading rate for the ANITA™ Mox process is about 1 kg N/m3/d and the Sjölunda facility has operated successfully at loadings up to 1.25 kg N/m3/d. The ANITA™ Mox process consumes about 1.4–1.7 kWh/kg N removed. Studies on N2O generation in the MBBR and the SBR process suggest that the MBBR produces less N2O—about 0.75 percent of the TN removed versus about 4.1 percent of the TN removed for the SBR process. In summary, the new, separate sidestream treatment process removes nitrogen, while using less power without carbon addition, pH,

January 2014 • Florida Water Resources Journal

or temperature control and producing less N2O than the parallel SBR process, which only provides nitrification.

Strass Wastewater Treatment Plant, Strass im Zillertal, Austria (Demon) The Achental-Inntal-Zillertal Wastewater Board owns and operates the Strass Wastewater Treatment Plant located in Strass im Zillertal (Tirol) Austria. The Strass plant is noted because it has achieved energy self-sufficiency— producing more power than it consumes. Strass is also where the pH controlled DEamMONification (Demon) separate sidestream treatment process was developed and first implemented. The Demon process has been in operation at Strass since 2004, and currently treats about 440–550 lb/d of nitrogen with maximum influent loads about 900 lb/d. The distinguishing characteristics of the Demon process are 1) pH control, 2) use of cyclones to retain anammox granules in the process, and 3) use of a SBR reactor configuration. No chemicals are added to the Demon process. The Demon is operated as an SBR with four cycles per day. The process is controlled within a very narrow pH band around 7.1. When the pH exceeds 7.1, the air is turned on, and when the pH drops below pH 7.09, the air is turned off. The Strass plant was commissioned in 1989 to provide wastewater service to the population of three valleys in Austria: the Achental, the Inntal, and the Zillertal. The plant discharges to the Isar River, one of the main tributaries of the Danube. The current ammonia limit is ≤ 5 mg N/L, and ≤ 10 mg/L during peak flows. Typical effluent nitrogen concentrations are 4 mg/L NH3, 5-12 mg/L NO3, and 2 mg/L NO2. The plant achieves 50-60 percent removal of TN in winter, and 80-90 percent removal of TN in the summer. The plant adds sodium aluminate to remove phosphorus. Effluent total phosphorus (TP) concentrations are typically about 0.5 mg/L. The treatment plant uses an A-B process as the mainstream treatment process. The A stage has a hydraulic retention time of about 15-20 minutes and a SRT of about 0.5 days. The A stage provides about 50 percent removal of BOD5, and no more than 10-15 percent removal of TKN. Two A-stage aeration tanks were constructed; however, the plant only uses one. The B stage uses a MLE-type process implemented in an oxidation ditch configuration consisting of four rectangular looped reactors, with each pair operating with anoxic and aerobic zones. There is mixed liquor recycle using submersible pumps with a maximum capacity of about 100 percent of design flow.

The plant has two egg-shaped digesters, and is able to produce about 1.8 ft3 of biogas per p.e. per day. The waste sludge from the A and B stages; internal grease; external fats, oils, and grease (FOG); and external food waste are mixed and then fed to the anaerobic digesters. It is estimated that the plant receives about 3,300 yd3/year in food waste, and about 1,300 yd3/year in grease. The digesters operate with an HRT of about 40 days in summer, but only 15 days in winter due to the high tourist loads. The digested sludge is thickened and then dewatered with a plate and frame press to a solids concentration of about 30 percent. The Demon process was implemented in the second, unused A-stage aeration tank. The ammonia concentration in the Demon feed (filtrate) varies seasonally between 1,600–2,000 mg/L. Filtrate COD concentration varies between 500–1,500 mg/L. Typical effluent from the Demon process consists of 10–100 mg/L NH3N, 30–100 mg/L NO3-N, <2 mg/L NO2-N, and 300 mg/L COD, with a maximum of 500 mg/L. Operating the Demon process at the Strass plant requires 0.5–1.0 hours per day of labor. In 2010, the plant generated about 10,900 kWh/d from biogas, which is about 160 percent of the power required to run the plant. Implementation of the Demon process at the Strass plant reduced overall plant power demand by about 8.5 to 12 percent. Overall energy demand at the Strass plant, per unit mass of nitrogen removed, has decreased over time: 6 kWh/kg N when operated as a conventional nitrification/denitrification process. ~3 kWh/kg N with sidestream nitrogen removal provided by nitritation-denitritation. 1.2 kWh/kg N with the current Demon process (nitritation/anammox).

Summary General guidelines have been published (van Loosdrecht, 2006) on factors to consider when evaluating the potential for implementing sidestream treatment. Depending on sitespecific conditions, in particular, the limiting aspects of the treatment process, either a separate or a combined process may be most beneficial. When nitrification or denitrification is limiting in the mainstream process, combined treatment (bioaugmentation) may provide the most benefit, as was demonstrated at both the Facility in Denver and the 26th Ward WPCP in New York. Separate treatment would be indicated if mainstream aeration capacity or carbon is limiting, or to reduce air or energy use, as was demonstrated at the Strass plant. Whether separate or combined sidestream treatment is best is a question that cannot be Continued on page 58 Florida Water Resources Journal • January 2014

Continued from page 57 answered in general, but must be answered for individual facilities. A variety of separate and combined sidestream treatment technologies have been developed and successfully implemented at full-scale municipal wastewater treatment plants. When appropriate circumstances exist, they offer a strong set of tools for reducing the cost of treatment and optimizing nitrogen removal in BNR processes.

A Glossary of Terms for Sidestream Treatment (some appear in the article) AOBs AOA Anammox

ammonia oxidizing bacteria ammonia oxidizing archaea anaerobic ammonium oxidation; oxidation of ammonium to nitrogen gas under anoxic conditions with nitrite as the electron acceptor; also a single-stage nitritation-anammox process using granular sludge. bioaugmentation seeding of a mainstream process with AOBs/NOBs grown in a sidestream reactor; also known as AT-3, BABE, BAR, CaRRB, and MAUREEN deammonification aerobic/anoxic process for autotrophic nitrogen removal where about onehalf of the NH4 is oxidized to NO2 and the remainder of the ammonia is converted together with the NO2 to nitrogen gas; also known as DEMON, CANON, OLAND, SNAP, and DIB denitrification anoxic process in which nitrite and nitrate are reduced to gaseous nitrogen oxides (nitric oxide (NO), nitrous oxide (N2O) and free nitrogen (N2) denitritation reduction of nitrite to nitrogen gas nitrification aerobic, sequential oxidation of ammonia to nitrite, and nitrite to nitrate nitritation aerobic oxidation of ammonia to nitrite; also known as SHARON or shortcut nitrification NOBs nitrite oxidizing bacteria Combined (Bioaugmentation) Processes AT-3 sidestream treatment process; named after NYC

BABE BAR CaRRB MAUREEN

26th Ward WPCP bioaugmentation batch enhanced process bioaugmentation regeneration process centrate and RAS reaeration process mainstream autotrophic recycle enabling enhanced N-removal

Separate (Shortcut Nitrification) Processes Sharon single reactor for high ammonia removal over nitrite Separate (Nitritation-Anammox) Processes Anammox™ nitritation-anammox process using a singlestage granular sludge bioreactor ANITA™ Mox nitritation-anammox process using a singlestage MBBR bioreactor CANON complete autotrophic nitrogen removal over nitrite DIB deammonification in interval-aerated biofilm system DeAmmon a nitritation-anammox process using a singlestage MBBR bioreactor DEMON pH controlled DEamMONification OLAND oxygen-limited autotrophic nitrification-denitrification SNAP single-stage nitrogen removal using the anammox and partial nitritation

•

References • Ahn, Y.-H. (2006) Sustainable Nitrogen Elimination Biotechnologies: A Review. Process Biochem., 41, 1709-1721. • Gustavsson, D. J. I. (2010) Biological Sludge Liquor Treatment at Municipal Wastewater Treatment Plants - A Review. VATTEN, 66, 179-192. • Hellinga, C.; Schellen, A. A. J. C.; Mulder, J. W.; van Loosdrecht, M. C. M.; Heijnen, J. J. (1998) The Sharon Process: An Innovative Method for Nitrogen Removal from Ammonium-Rich Waste Water. Water Sci. Technol., 37 (9), 135-142. • Henze, M.; van Loosdrecht, M. C. M.; Ekama, G. A.; Brdjanovic, D. (2008) Biological Wastewater Treatment: Principles, Modeling, and Design. IWA Publishing, London, UK. • Katehis, D.; Stinson, B.; Anderson, J.; Gopalakrishnan, K.; Carrio, L.; A., P. (2002) Enhancement of Nitrogen Removal thru In-

January 2014 • Florida Water Resources Journal

•

novative Integration of Centrate treatment. Proceedings of the 75th Annual Water Environment Federation Technical Exhibition and Conference; Chicago, IL, Sept. 29 – Oct. 2; Water Environment Federation: Alexandria, VA. Kos, P. (1998) Short SRT (Solids Retention Time) Nitrification Process/Flowsheet. Water Sci. Technol., 38 (1), 23-29. Leu, S.-Y.; Stenstrom, M. K. (2010) Bioaugmentation to Improve Nitrification in Activated Sludge Treatment. Water Environ. Res., 82, 524-535. Luna, B.; Narayanan, B.; Rogowski, S.; Walker, S. (2010) Metro's CaRRB Diet - Centrate Treatment Process Tackles Big Challenges in a Small Package. Proceedings of the 83rd Annual Water Environment Federation Technical Exhibition and Conference; New Orleans, Oct. 2 – 6; Water Environment Federation: Alexandria, VA. Mulder, J. W.; Duin, J. O. J., Goverde, J.; Poiesz, W. G.; van Veldhuizen, H.M.; van Kempen, R.; Roeleveld, P. (2006) Full-scale experience with the Sharon process through the eyes of the operators. Proceedings of the 79th Annual Water Environment Federation Technical Exhibition and Conference; Dallas, TX, Oct. 21 – 25; Water Environment Federation: Alexandria, VA. Parker, D.; Wanner, J. (2007) Review of Methods for Improving Nitrification through Bioaugmentation. Water Practice, 1, 1-16. Ramalingam, K.; Thomatos, S.; Fillos, J.; Dimitrios, K.; Deur, A.; Navvas, P.; Pawar, A. (2007) Bench and Full Scale Evaluation of an Alternative Sidestream Bioaugmentation Process. Proceedings of the 83rd Annual Water Environment Federation Technical Exhibition and Conference; San Diego, Oct. 13 – 17; Water Environment Federation: Alexandria, VA. van der Star, W. R.; Abma, W. R.; Blommers, D.; Mulder, J. W.; Tokutomi, T.; Strous, M.; Picioreanu, C.; van Loosdrecht, M. C. (2007) Startup of Reactors for Anoxic Ammonium Oxidation: Experiences from the First FullScale Anammox Reactor in Rotterdam. Water Res., 41 (18), 4149-4163. van Dongen, L. G. J. M.; Jetten, M. S. M.; van Loosdrecht, M. C. M. (2001) The Combined Sharon/Anammox Process – A Sustainable Method for N-Removal from Sludge Water. IWA Publishing: London, UK. van Loosdrecht, M. C. M.; Salem, S. (2006) Biological Treatment of Sludge Digester Liquids. Water Sci. Technol., 53 (12), 11-20. Wett, B.; Rostek, R.; Rauch, W.; Ingerle, K. (1998) pH-Controlled Reject Water Treatment. Water Sci. Technol., 137 (2), 165-172.

Certification Boulevard

Roy Pelletier

Test Your Knowledge of Wastewater Treatment Topics

1. Which is a higher life form in the activated sludge process: a free swimming ciliate, a stalked ciliate, or a rotifer? a. Free swimming ciliate b. Stalked ciliate c. Rotifer d. They are all the same.

6. Which group of bacteria is responsible for conversion of inorganic ammonia in wastewater? a. Carbon eaters b. Methanogens c. Autotrophic d. Heterotrophic

2. Given the following data, what is the solids loading rate on the secondary clarifiers? • Plant influent flow is 5.5 mgd • The return activated sludge (RAS) rate is 50 percent of Q • There is one 100-ft diameter secondary clarifier • The aeration mixed liquor suspended solids (MLSS) is 2,200 mg/L a. 19.3 lbs/day/ft2 b. 8.6 lbs/day/ft2 c. 18.9 lbs/day/ft2 d. 15.5 lbs/day/ft2

7. What is the advanced stage of activated sludge called when bacteria oxidize their own cell mass? a. Log growth b. Declining growth c. Cathodic protection d. Endogenous respiration

3. What is the best definition of a shock load? a. An unexpected bump. b. A strong influent waste strength. c. A high concentration of total suspended solids (TSS). d. A heavy truck load entering the plant. 4. Which condition may produce the best denitrification efficiency in an aeration tank? a. High air supply b. High aeration dissolved oxygen (DO) c. Low aeration DO d. Low RAS rate 5. Which zone of a biological nutrient removal (BNR) plant produces a release of phosphorus and is responsible for conditioning the phosphorus for later uptake in the downstream zones? a. Anoxic b. Fermentation c. Aerobic d. Reaeration

8. Which group of bacteria can be facultative and are responsible for carbonaceous biochemical oxygen demand (CBOD5) removal and denitrification in the activated sludge process? a. Heterotrophic b. Nitrosomonas c. Autotrophic d. Fermenters

LOOKING FOR ANSWERS?

Check the Archives Are you new to the water and wastewater field? Want to boost your knowledge about topics youʼll face each day as a water/waste-water professional? All past editions of Certification Boulevard through the year 2000 are available on the Florida Water Environment Associationʼs website at www.fwea.org. Click the “Site Map” button on the home page, then scroll down to the Certification Boulevard Archives, located below the Operations Research Committee.

9. How much alkalinity is required to convert 1.0 lb of ammonia-nitrogen during the nitrification process? a. 7.2 lbs b. 8.34 lbs c. 7.48 lbs d. 4.6 lbs 10. Which adjustment will create an increased contact time in the aeration tank? a. Lower the weir. b. Increase the air supply rate. c. Decrease the WAS rate. d. Decrease the RAS rate. Answers on page 78

SEND US YOUR QUESTIONS Readers are welcome to submit questions or exercises on water or wastewater treatment plant operations for publication in Certification Boulevard. Send your question (with the answer) or your exercise (with the solution) by email to roy.pelletier@cityoforlando.net, or by mail to: Roy Pelletier Wastewater Project Consultant City of Orlando Public Works Department Environmental Services Wastewater Division 5100 L.B. McLeod Road Orlando, FL 32811 407-716-2971

Florida Water Resources Journal • January 2014

SPOTLIGHT ON SAFETY

2013 FWEA Safety Awar d Doug Prentiss Sr. pplications for the 2013 FWEA safety awards started coming in early this year, with several inquiries received at the end of the year, which is a good indicator for water reclamation workers around our state. We have changed the submission requirements over the years based on the date of the Florida Water Resources Conference, where the awards are given out during the FWEA luncheon.

First-, second-, and third-place plaques are eligible for Class A, B, C, and D treatment and reclamation facilities. The FWEA Top Ten program also recognizes organizations that promote safe operations. Applications can be accessed at www.fwea.org in the awards section, or by contacting me at dougprentiss@windstream.net. The application can also be downloaded from my website at www.dougprentiss.com. Please note the new section for emergency response and high-hazard workers and teams. Electronic submittals are not required but are encouraged. Please remember to include a

picture of your facility, along with a brief description of why your organization was awardworthy in 2013. Your picture could end up in a future issue of this magazine. The final day for submission for any categories of the 2013 FWEA safety awards is Feb. 15, 2014. Doug Prentiss is president of DPI, providing a wide range of safety services throughout Florida. He also serves as chair of the Florida Water Environment Association Safety Committee.

FLORIDA WATER ENVIRONMENT ASSOCIATION 2013 SAFETY AWARD APPLICATION Facility Name: ______________________________ __________________________________________ Facility Mailing Address: ______________________ __________________________________________ __________________________________________ Facility Phone Number: _______________________ Facility Address (if different from mailing address): __________________________________________ __________________________________________

ACCIDENT POTENTIAL RATING (Please check all processes and chemicals used at your facility.) Raw Sewage Pumping Primary Clarifiers Sludge hauling Mechanical Mixers Reuse/Effluent Pumping Aerobic Digestion Sludge Thickening Mechanical Incineration Aerated Lagoon

Screening Activated Sludge Blowers Secondary Clarifiers Post Aeration Holding Tanks Vacuum Filters Application Composting

Grit Removal Filters Pure Oxygen Generation Sludge drying Anaerobic Digestion Sludge Thickening – Gravity Drying Beds Lagoon/Polishing Ponds Lime Stabilization

__________________________________________

HAZARDOUS CHEMICALS USED: (State Pounds or Gallons used per day.)

Facility Category: (A. B, C, or D)

________

Average Daily Flow (mgd):

________

Number of Employees at Facility:

________

Chlorine.................................. Alum ...................................... Methanol ................................ Ozone .................................... Potassium Permanganate...... Hydrogen Peroxide ................

Number of Man-hours Worked at the Facility (January 1 to December 31, 2013): ________ Number of Lost Days for 2013:

________

When was last accident resulting in a fatality?

________

List type of accidents: 1. ________________________________________ 2. ________________________________________ 3. ________________________________________ On a separate attachment, describe your facility safety program. Be sure to include in your description the number of safety training sessions, subjects covered, and length of training in hours during the 2013 calendar year. Each facility must show actual man-hours spent at that facility and safety training done for that facility. Electronic submissions may be sent to dougprentiss@windstream.net Please include a digital photo of your operation.

________ ________ ________ ________ ________ ________

SO2.................................. Acid .................................. Lime ................................ Polymer............................ Caustic ............................ Chlorine Compounds ......

Other Chemicals: Identify Type, %, and GPD 1. ____________________________________________________________________ 2. ____________________________________________________________________ 3. ____________________________________________________________________ 4. ____________________________________________________________________ SAFETY TEAMS: Examples: FlaWARN, Confined Space Rescue, Emergency Response, First Responders, Airline/SCBA Entry Teams, or any safety related group designated to perform safety functions for your facility. Please list name and purpose, additional narrative can be attached. 1. ____________________________________________________________________ 2. ____________________________________________________________________ 3. ____________________________________________________________________ 4. ____________________________________________________________________ 5. ____________________________________________________________________

Application Deadline: Feb. 15, 2014. Return completed application to: FWEA Safety Committee c/o Doug Prentiss, 13409 NW 202 Street, Alachua, FL 32615 Office/home Phone: (386) 462 3085 • Cell: 352 538 3491 • E-mail: dougprentiss@windstream.net

________ ________ ________ ________ ________ ________

January 2014 • Florida Water Resources Journal

F W R J

Getting More Out of Activated Sludge Plants by Using a BioMag Process Derya Dursun and Jose Jimenez s nutrient requirements are tightening in the United States, one of the biggest challenges in wastewater treatment has become to reliably meet effluent limits in a sustainable manner. The reliability requirement is driven by the need to meet strict effluent daily or weekly limits set in permits to protect the designated uses of the receiving water. Hence, facilities facing more strict nutrient requirements have to consider a wide, and possibly confounding, array of treatment technologies. In order to address this issue, The U.S. Environmental Protection Agency (EPA) has recently published a technical document that includes process descriptions and operating factors for over 40 different treatment technologies for removing nitrogen, phosphorus, or both, from municipal wastewater streams ( EPA, 2009). Nutrient removal processes, however, come at a cost to municipal wastewater treatment facilities and their ratepayers. Although funding from various sources might be available, they are not generally sufficient to address all aspects of the necessary improvements for nutrient removal. Another important factor affecting the cost of nutrient removal at wastewater facilities is site limitations on physical expansion of their treatment facilities. Some plants are located in urban areas and do not have any way to obtain the physical space necessary to expand. Space limitations can severely limit the type of processes that can be used to reduce

nutrients (Naik and Strenstrom, 2011). Therefore, the BioMag process is a recently developed, emerging technology that aims to increase the capacity of treatment plants and to enhance nutrient removal in facilities that have limited spaces.

Objectives The main objective of this article is to introduce the BioMag process as an alternative to enhance the capacity and effluent quality of existing treatment plants. Objectives that are more specific are: To present the BioMag process and to provide the advantages and disadvantages of this emerging technology. To investigate nutrient removal capacity of this technology by providing several examples from existing pilot scale projects. To discuss the design considerations of the BioMag process. To provide a case study to compare the footprint of the BioMag process with other alternatives.

BioMag Process The BioMag process is a ballasted flocculation-aid wastewater treatment process that uses magnetite to increase the specific gravity of biological floc. It was developed and patented by Cambridge Water Technology (CWT) in 2010 (Woodard et al., 2010),

Figure 1. Comparison of Flocs With and Without Magnetite Addition (from Andryszak et al., 2011)

January 2014 â&#x20AC;˘ Florida Water Resources Journal

Derya Dursun, Ph.D., P.E., is process engineer and Jose Jimenez, Ph.D., P.E., is vice presidentâ&#x20AC;&#x201D;technology and innovation at Brown and Caldwell in Maitland.

which is currently owned by Siemens. Magnetite (Fe3O4) is an inert iron ore, with a specific gravity of 5.2 and a strong affinity for biological solids. In this process, magnetite integrates with the biological floc, substantially increases the settling rate of the biomass, and improves overall solids removal. Figure 1 depicts the magnetite-introduced floc (right side) and compares it with normal floc. The dark spots appear on the right image are magnetite added into the process. The BioMag process provides the ability to operate the reactors at three to four times above traditional activated sludge process mixed liquor suspended solids (MLSS) concentrations, while still maintaining adequate settling and thickening in the secondary clarifiers. This allows existing activated sludge systems to treat two to three times the original design flows and loadings at food-to-microorganism ratios (F/M), which are similar to conventional activated sludge systems, thereby increasing plant capacity within the same footprint. The process also facilitates nitrogen and phosphorus removal by allowing plants to increase the sludge retention time (SRT) and free up existing aeration tankage for use as anoxic and/or anaerobic zone(s). It provides enhanced and reliable removal of suspended solids, nitrogen, and phosphorus. A schematic diagram of the BioMag process is illustrated in Figure 2. Mixed liquor is introduced with both recovered and virgin magnetite in a continuously mixed tank before entering into activated sludge. Then, mixed liquor, including magnetite, is fed into the reactor where it is held in suspension through a combination of aeration and supplemental mechanical mixing. After clarifiers, the return activated sludge (RAS) is conveyed from the clarifier to the reactor. Activated sludge is wasted from the RAS line and sent to a magnetite/waste activated

sludge (WAS) separation system for removal of the magnetite prior to the sludge processing. The magnetite removed from the WAS line is recovered and sent into the mixing tank. The magnetite separation and recovery process starts with shear mills that apply high-shear forces to break up the floc. It is then followed by a rotating magnetic drum to separate the magnetite from the WAS. Once separated, the WAS is sent to solids processing facilities. The BioMag magnetite recovery process has an efficiency rate of 85 to 95 percent. Makeup magnetite is added to maintain the design MLSS-to-magnetite weight ratio of 0.8 to 1.5 (optimum 1), depending on the application. Approximately 100 lbs of makeup magnetite are needed for mil gal (MG) of wastewater treated, based on an approximation of the total sludge yield being 1 dry ton/MG of wastewater treated. Average cost for magnetite has been around $0.25/lb, which would be at $25 of magnetite cost for 1 MG wastewater treated. The main advantage of the BioMag process is that it can easily be applied to the conventional activated sludge process in confined spaces, with the advantage of eliminating the need of any additional enhanced nutrient removal (ENR) reactor and/or clarification capacity. It can notably enhance the capacity of the facility, improve secondary effluent quality, and increase the nutrient removal capacity of the plant. The BioMag process also offers significant capital cost/benefits compared to traditional biological processes. On the other hand, there are some disadvantages of this technology not identified until recently. The process is still in the infant phase, where there are some unknowns. The facility that decides to implement this technology would need to make some assumptions and would involve some risks associated with the technology. Conducting a pilot-scale project before implementation of the full-scale process would lower the risk; however, the process does not have much established information like other traditional processes. Other than that, the BioMag process is not suited for intermittent operation. The life of shear mills necessary for the separation of magnetite from biological flocs has been questionable. If the facility does not have an influent fine screen or primary clarifiers, a fine screen should be incorporated into the WAS line to protect the shear mill from becoming clogged or damaged. The process can also be energy intensive due to high mixing requirements and the amount of shear necessary to break the flocs in mag-

Figure 2. Schematic Diagram of BioMag Process (from Siemens)

Table 1. List of BioMag Process Applications

netite separation step. Major challenges of the BioMag process are addressed in the process design considerations section.

Nutrient Removal Capability Due to the fact that the BioMag process is still being developed, there is limited data available on nutrient removal capacity of the process. Table 1 provides the list of BioMag projects. As indicated in Table 1, almost all BioMag applications aim to enhance nutrient removal. Although the data from some facilities have been published in various conference proceedings, some facilities are in the construction or design phase where no data are available. The Sturbridge Wastewater Treatment Plant (WWTP) in Massachusetts has completed successful full-scale demonstration that doubled the capacity of the plantâ&#x20AC;&#x2122;s activated sludge system, resulting in BioMag process selection for application. This facility has a 1.3-mgd treatment capacity and in-

cludes an ENR upgrade, utilizing existing tankage. After the successful pilot project, construction activities were initiated in February 2010 and the project was completed in the summer of 2012. There were many challenges in the startup of the project; however, data collected to date clearly show that effluent total nitrogen (TN) and total phosphorus (TP) values of 3.0 mg/l and 0.05 mg/l are achievable (Catlow & Woodard, 2012). Another successful full-scale demonstration was conducted at Upper Gwynedd WWTP in Pennsylvania. This facility includes a 3-mgd enhanced nutrient removal upgrade and a 13-mgd wet weather flow treatment, utilizing existing tankage. This facility had to demonstrate TP < 0.2 mg/l while maintaining effluent total suspended solids (TSS) < 10 mg/l monthly average, TSS< 30 mg/l during a wet weather event, and effluent cBOD<5 mg/L. The results indicated that the facility could meet effluent requirements by implementing the BioMag process. Continued on page 64

Florida Water Resources Journal â&#x20AC;˘ January 2014

Continued from page 63 The Mystic WWTP located in Connecticut was in need of a process upgrade to meet future requirements for effluent total nitrogen. A full-scale demonstration of the BioMag process was completed from September 2009 through January 2010 to verify achievement of required process performance (Moody et al., 2011). Based on the results from the demonstration project, the facility could meet effluent TN<5 mg/L and effluent ammonia <1 mg/L. The sludge volume index (SVI) was around 80 mL/g. A pilot-scale project was conducted at the Winebrenner WWTP, located in Maryland. This four-stage Bardenpho facility is required to have a 0.6-mgd capacity, with an ENR upgrade utilizing existing tankage. The process has to achieve effluent TN <3.0 mg/L and TP < 0.3 mg/L. A full-scale four-month demonstration financed by the Maryland Department of Environment (MDE) met all success criteria. The BioMag process was operated for varying influent loading conditions at a MLSS concentration of 10,000 mg/L between 6-11°C, achieving TN < 3 mg/L, TP < 0.2 mg/L, and TSS < 5 mg/L without the use of effluent filters (Andryszak et al., 2011). The 1.1-mgd-capacity Taneytown WWTP located in Maryland has two sequencing batch reactors (SBRs). A full-scale trial of the BioMag process was conducted in 2010, representing its first application to an SBR. The full-scale project demonstrated effluent TN and TP concentrations averaging 1.2 mg/L and 0.11 mg/L, respectively. The facility could successfully meet all perform-

ance requirements (TN < 3.0 mg/L and TP < 0.3 mg/L) by adopting the BioMag process (Lubenow et.al., 2011). Although, BioMag is an emerging technology, it presents promising results for ENR in pilot- and full-scale demonstration projects. Still, application of this technology in full-scale projects is needed to be able to establish the capabilities in nutrient removal.

Process Design Considerations As indicated previously, there are many areas that are not clearly identified in this process. The first issue is the conveyance of solids, which includes magnetite. The transportation of dense solids in RAS and WAS lines might require higher energy pump capacity; however, settling in these lines must be eliminated. The impact of magnetite on the life of pipes, pumps, and valves is not well defined. The data available do not show major wear of equipment; however, since the process only developed several years ago, there is no sufficient time to monitor this aspect of the process. Another major area that requires further research and assessment is the mixing and aeration requirements of the BioMag process. Mixing is a crucial part of the process, not only to contact solids with magnetite, but also to prevent the mixed liquor stratification. The high-dense flocs can easily settle down in aeration tanks; hence, additional mixers would be necessary to keep the flocs in suspension all the time. Mixing can be very energy intensive and could notably

increase the operating cost. Other than mixing, the impact of magnetite addition on alpha value (ratio of process-to-clean-water mass transfer) has to be clearly identified. The issue has been addressed in several projects; however, further research is essential to determine this value, which has a major impact on aeration requirement of the process. Addition of magnetite into biological flocs would vary the coagulation and flocculation kinetics, and the role and dose of coagulants in a magnetite-introduced process needs to be evaluated. The facility might need to change the chemical conditioner and/or dose, and to conduct optimization studies. The pH and alkalinity response would also have to be monitored. Foaming was a major problem of the BioMag process that was identified at the Sturbridge WWTP (Figure 3). Following startup of the facility’s new BioMag system, foaming was observed in each of the package treatment units. Microscopic examination of the facility’s mixed liquor indicated that much of this foaming is attributable to microthrix parvicella and nocardia bacteria. The abundance of filaments observed at startup was believed to be due to the prevalence of these bacteria during temporary treatment system operation (Catlow & Woodard, 2012); however, this issue has to be investigated comprehensively. The facility tried various methods to resolve foaming issues, such as RAS chlorination, defoamers, and surface wasting. Surface wasting was identified as the most effective method to address the foaming issue; however, it was labor intensive. Fate of residual magnetite that is wasted through WAS (the capture rate is around 95 percent) is also not known at this stage. Accumulation of magnetite in solids processes (such as digesters) could be problematic. Furthermore, the impact of magnetite in dewatering processes has not yet been reported. Another important consideration is continuous facility operation while retrofitting the BioMag process into the existing facility. During retrofitting, when several process units were offline, the facility still has to meet the permit requirements; temporary units, flow diversion, and various modifications might be necessary, especially in wet weather events.

A Case Study: Comparison of the Biomag Process With Conventional Technologies Figure 3. Foaming Observed at Sturbridge Wastewater Treatment Plant (from Catlow & Woodard, 2012)

January 2014 • Florida Water Resources Journal

The Marlay Taylor Water Reclamation Facility (WRF) in Maryland has a new permit to reduce the effluent nitrogen and phos-

phorus loads from the facility to ENR levels and to achieve 3mg/L TN and 0.3 mg/L TP; the WRF has explored cost- and energy-effective solutions to upgrade the facility to meet these ENR requirements. Three process alternatives were compared for required footprint and initial capital cost, along with a 15-year present-worth analysis. The fourstage Bardenpho process was selected for the conventional alternative, and integrated fixed-film activated sludge (IFAS) was also used for comparison. In this facility, the footprint of the BioMag process was found to be significantly smaller than other options, since this process eliminates the need for adding a secondary clarifier and effluent filters (Figure 4). Since the BioMag process eliminates the need for building additional units, this alternative would require notably lower initial capital costs compared to the conventional four-stage Bardenpho and hybrid IFAS processes. For a 6-mgd annual average flow, the capital cost of BioMag was around 34 percent less than the four-stage Bardenpho and 25 percent lower than the IFAS process (Dursun et al., 2012). On the other hand, the BioMag process was shown to be energy intensive due to the high mixing requirements and additional energy consumption of the process-related equipment (Figure 5). Additional mixing, compressors, and shear mills to separate the magnetite from flocs, separators, and pumps would significantly increase the energy demand of the conventional process. As a basis for comparing the various options, a present-worth analysis was also conducted for the WRF. The capital costs were inflated to 2011 dollars, which represent the present worth. Energy and maintenance costs were multiplied by the annual presentworth factors that provide the present worth for a series of values for a 15-year period. An interest rate of 4.67 percent was used in the analysis. Figure 6 exhibits the 15-year present-worth value of each alternative (Dursun et al., 2012). Based on this analysis, the presentworth value of the three alternatives were quite similar to each other. The conventional four-stage Bardenpho process showed slightly higher value compared to the other two alternatives.

Conclusions The BioMag process is a promising emerging technology that might provide potential solutions for WWTPs that have to meet strict ENR requirements in limited spaces:

Figure 4. Comparison of Process Footprint (Required Area/Flow to be Treated)

Figure 5. Comparison of Energy Requirement

Based on demonstration and pilot-scale projects, the process demonstrated its ability to handle high MLSS concentrations and to achieve settling at a very high solids loading rate. The process was proven to be successful in achieving ENR levels when adopted in different process configurations and used to treat a wide variation of flows and loads. The BioMag process would provide more capacity without building additional unit(s) in treatment plants, while meeting tighter ENR requirements.

However, the process has to be implemented full scale to establish more details of the process that are not clearly identified at this point. Besides many advantages, the process has some challenges, such as conveyance of solids, air and mixing requirements, equipment wear, foaming, the role of coagulants/chemicals, and the fate of residual magnetite in biosolid processes. These areas require more research and investigation. The initial capital costs for the implementation of the process are relatively low compared to conventional processes. On the other hand, the process might be energy intensive compared to other options. Continued on page 66

Florida Water Resources Journal â&#x20AC;˘ January 2014

Continued from page 65

References • Andryszak R., Woodard S., Nash K., Duffy K. (2011) Enhanced Nutrient Removal Up-

grade of the Winebrenner Wastewater Treatment Plant Using BioMag™ Technology, WEFTEC Proceedings, Los Angeles, CA. • Catlow I., Woodard S. (2009) Ballasted Biological Treatment Process Removes Nutrients and Doubles Plant Capacity,

Figure 6. Present-Worth Analysis for Marlay Taylor Water Reclamation Facility

January 2014 • Florida Water Resources Journal

WEFTEC Proceedings, Orlando, FL. • Catlow I., Woodard S. (2012) Startup of the Nation’s First Combined BioMag/CoMag Treatment Facility: Challenges and Successes, WEFTEC Proceedings, New Orleans, LA. • Dursun D., Jimenez J., Briggs A. (2012) Comparison of Process Alternatives for Enhanced Nutrient Removal: Perspectives on Energy Requirements and Costs, WEFTEC Proceedings, New Orleans, LA. • Lubenow B.L., Woodard S., Stewart D.W., Kirkham R.A. (2011) Maximizing Nutrient Removal in an Existing SBR With a FullScale BioMag Demonstration, WEFTEC Proceedings, Los Angeles, CA. • Moody M.B, Bishop A., McConnell W.C. (2011) Beyond Desktop Evaluation: Key Design Criteria for Mixing and Settling of Magnetite-Impregnated Mixed Liquor, WEFTEC Proceedings, Los Angeles, CA. • Naik K., and Strenstrom M. (2011) Economic and Feasibility Analysis of Process Selection and Resource Allocation in Decentralized Wastewater Treatment for Developing Regions, WEFTEC Proceedings, Los Angeles, CA. • U.S. EPA (2009), Nutrient Control Design Manual EPA 600-R-09-012, Cincinnati, OH.

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For more information call the

FWPCOA Training Office 321-383-9690 Florida Water Resources Journal • January 2014

Third Annual Water Festival a Huge Success Kevin M. Vickers Last October brought cooler weather and the annual Florida Water Festival to central

Many attendees visited the face painting booth.

Florida. Sponsored by the Central Florida Chapter of FWEA, the third annual festival was hosted at Crane’s Roost Park in Altamonte Springs on October 26. And what a success this event has become! Over 400 attendees joined volunteers and vendors to celebrate water, our most precious resource. The participants enjoyed live music, food, and face painting, all while learning a little more about the importance of water. Some attendees were even able to have caricatures of themselves drawn at the caricature booth. One of the main events each year at the festival is the annual Walk for Water. Participants are separated into age groups and compete by carrying as many one-gallon water jugs as they can around the park track. Scores for the event were based on the number of gallons and the total distance that each participant walked. The Walk for Water is an event that helps participants appreciate the weight of water and the effort that is required to transport it over long distances, as is done in many developing countries (mostly by women and children) every day. This year, the

January 2014 • Florida Water Resources Journal

event grew to 67 participants. Combined, they carried a total 214 gallons of water over 89 total miles. Congratulations to this year’s overall winner, John Mercer, who walked a total of 20 gallon-miles. Another very popular event is the student design competition. Students were challenged with designing and constructing a water filtration system. Then, each competitor system was tested with two cups of contaminated water. Filtration systems were judged for total volume passing the filter in 10 minutes and the turbidity after filtration. Congratulations to this year’s winners: Kaitlyn Bowman, Eliza Middleton, and Kyle Koehne from Milwee Middle School. Several exhibitor booths were set up around the park, representing Reiss Engineering, South Florida Water Management District,

Participants in the student design competition test their filters.

City of Sanford, Florida Water and Pollution Control Operators Association, City of Orlando Wastewater Division, City of Altamonte Springs, American Society of Civil Engineers, Seminole County Conservation, Seminole County Water Shed Management, Green Edge/FWEA Biosolids, City of Mount Dora, and UF/IFAS Master Gardener Program. This year’s festival was free to attendees and was made possible by generous volunteers and sponsors. Many thanks to the volunteers who

Participants on the Walk for Water.

Students in the student design competition wait for the results from the judges.

helped organize and run the event, and a special thank you to our sponsors: Hazen and Sawyer, CH2M HILL, City of Orlando, Orlando Utilities Commission, Florida Water Environment Association, AECOM, Barnes Ferland & Associates, Carollo Engineers, CPH, FWPCOA, Garney Construction, HDR, MTS Environmental, Reiss Environmental, Arcadis, Brindley Pieters and Associates, CDM Smith, Green Technologies, Heyward, Neel-Schaffer, and Tetra Tech. The Central Florida Chapter has already

begun planning for this year’s event. If you are interested in helping, please contact the Florida Water Festival Committee Chair Stacey Smich (Stacey.smich@ch2m.com). For additional information and pictures of the 2013 festival, check out the Florida Water Festival’s Facebook page (https://www.facebook.com/FloridaWaterFestival). Kevin M. Vickers, E.I., is project engineer with Kimley-Horn and Associates Inc. in Ocala.

Florida Water Resources Journal • January 2014

C FACTOR

Awards, Web Recognition, and Training Opportunities Jeff Poteet President, FWPCOA ow—2014 has arrived! It is hard for me to imagine that another year has passed. As I get older, the years seem to go by faster and faster; it must have something to do with the space—time continuum! As I reflect on this past year as your president, I am once again humbled by the support of the industry, and especially the members of our Association who help move this great organization forward. Our industry as a whole continues to benefit as our members are educated by those who have practical experience in the things that we do. I hope that 2014 will be a

successful and prosperous year for all!

Final 2013 Board Meeting The board of directors met last November and several notable matters transpired. The board voted to put on a backflow tester course at the Pinellas County Technical Institute (P-Tech) at no cost. This training effort is to show our appreciation for the continued support P-Tech (an appropriate acronym for anyone in our industry!) has rendered over the years. Brad Hayes with the Florida Water Environment Association (FWEA) attended the meeting and thanked FWPCOA for our continued support of the Operator’s Challenge. If you don’t know, this is an annual competition for teams of utility personnel

from across the United States. The timed competition challenges the knowledge and abilities of the teams in the areas of process control, safety, maintenance, collections, and laboratory procedures. This is truly an outstanding event that our sister organization puts on and I encourage your utility, or better yet, your region, to put together a team and compete in this event. For more information on the Operator’s Challenge, please visit www.fwea.org. Our Awards Committee chair, Rene Moticker, gave a brief report on the committee’s activities. Rene reminded our regional directors of the FWPCOA awards program. She asked the directors to remind their membership to submit nominations for our awards that will be given out at the Florida Water Resource Conference in April, and for those that will be given out at our August awards banquet. Although these dates seem far in the future, they will be here before you know it. One of the best things we do as an organization is to recognize excellence in our industry. Please take the time to nominate those worthy for the recognition that they deserve. The award criteria and applications can be found at www.fwpcoa.org/awards.asp. The election of officers took place at the November meeting and the current slate of officers will server another term: Dave Clanton (secretary-elect), Rim Bishop (secretary), Ray Bordner (past president), Dave Denny (vice president), and myself (president) will serve as the executive board in 2014. I am truly thankful to have the opportunity to work with such an outstanding group of people for another year. Please do not hesitate to contact anyone of us with any concerns, suggestions, or training requests that you might have and we will work as a team to make your inquiry meet your expectations.

Webmaster Recognition Speaking of recognition, I would like to highlight the efforts of the Association’s webmaster, Walt Smyser. Walt has supported the Association on both a regional and state

January 2014 • Florida Water Resources Journal

level for many years. He is extremely responsive to the requests from our membership and continually offers solutions to issues that arise from time to time. An example of this would be a recent request by this magazine to implement an automatic link from our website job board to its website. Walt immediately tackled this task and found a solution that met everyone’s needs. Walt’s knowledge of the industry has benefited the Association on many levels. Thank you, Walt, for your efforts and continued contributions!

of our current members engaged in the Association that our total membership will increase as a result of their enthusiasm. Therefore, in my second term as your president, I am going to focus on ways to get our current members more involved. In 2014, we will have some outstanding training opportunities for those who want to expanded their knowledge and, at the same time, acquire continuing educations credits for license renewal. The FWPCOA will have two state short schools this year: one in March and another in August. The Spring Short School, to be held

March 24-28, will be hosted at the Indian River State College and applications are available online. If you are unable to attend one of the state schools, there will be training offered by all 13 of our regions. If you are looking for some online training, our online program has expanded over the years and has an array of topics to choose from. Please see our website (www.fwpcoa.org) for more information on the Association and additional regional information. Our next board meeting will be held in Hollywood on January 11. I hope to see you there!

Education and Training Goals At the beginning of my tenure as your president I had set several goals. Many of these challenges were accomplished as our training programs have expanded and all of our regions have held training opportunities for their membership. However, the membership goal I set—an optimistic one—did not come to fruition. In order for our organization to continue to grow, we need to find ways to expand our membership. The expansion of our membership needs to occur in two areas: total membership and members who are engaged in the Association. Both of these areas have challenged past presidents during their tenures. This past year, I visited several of our regions in an effort to find out what they are doing that makes them successful. I was hoping to see more involvement; however, it seems to me that there are core individuals who are intrinsically driven that help make their regions successful. I personally believe if we get more

Florida Water Resources Journal • January 2014

ENGINEERING DIRECTORY

Tank Engineering And Management Consultants, Inc.

Engineering • Inspection Aboveground Storage Tank Specialists Mulberry, Florida • Since 1983

863-354-9010 www.tankteam.com

January 2014 • Florida Water Resources Journal

ENGINEERING DIRECTORY

Fort Lauderdale 954.351.9256

Jacksonville 904.733.9119

Miami 305.443.6401

Orlando 407.423.0030

Gainseville 352.335.7991

Key West 305.294.1645

Navarro 850.939.8300

Tampa 813.874.0777 813.386.1990

West Palm Beach 561.904.7400

Naples 239.596.1715

Showcase Your Company in the Engineering or Equipment & Services Directory Contact Mike Delaney at 352-241-6006 ads@fwrj.com

EQUIPMENT & SERVICES DIRECTORY

Florida Water Resources Journal â&#x20AC;˘ January 2014

EQUIPMENT & SERVICES DIRECTORY

Motor & Utility Services, LLC

Instrumentation,Controls Specialists Instrumentation Calibration Troubleshooting and Repair Services On-Site Water Meter Calibrations Preventive Maintenance Contracts Emergency and On Call Services Installation and System Start-up Lift Station Controls Service and Repair

Central Florida Controls,Inc. Florida Certified in water meter testing and repair P.O. Box 6121 • Ocala, FL 34432 Phone: 352-347-6075 • Fax: 352-347-0933

w w w. c e nt r a l f lor i d a c ont rol s . c om

January 2014 • Florida Water Resources Journal

CEC Motor & Utility Services, LLC 1751 12th Street East Palmetto, FL. 34221 Phone - 941-845-1030 Fax – 941-845-1049 prademaker@cecmotoru.com • Motor & Pump Services Test Loaded up to 4000HP, 4160-Volts • Premier Distributor for Worldwide Hyundai Motors up to 35,000HP • Specialists in rebuilding motors, pumps, blowers, & drives • UL 508A Panel Shop, engineer/design/build/install/commission • Lift Station Rehabilitation Services, GC License # CGC1520078 • Predictive Maintenance Services, vibration, IR, oil sampling • Authorized Sales & Service for Aurora Vertical Hollow Shaft Motors

EQUIPMENT & SERVICES DIRECTORY

CLASSIFIEDS Positions Av ailable Purchase Private Utilities and Operating Routes Florida Corporation is interested in expanding it’s market in Florida. We would like you and your company to join us. We will buy or partner for your utility or operations business. Call Carl Smith at 727835-9522. E-mail: csmith@uswatercorp.com

WATER PLANT OPERATOR CITY OF TEMPLE TERRACE Technical work in the operation of a water treatment plant and auxiliary facilities on an assigned shift. Performs quality control lab tests and other analyses, monthly regulatory reports, and minor adjustments and repairs to plant equipment. Applicant must have State of Florida D.E.P. Class “A”, “B”, or “C’ Drinking Water Certification at time of application. Salary Ranges – “A”-$17.33 – 26.01; “B”-$15.76-23.65; “C”-$14.33-21.50. Excellent benefits package. To apply and/or obtain more details contact City of Temple Terrace, Florida, Human Resources at (813) 506-6430 or visit www.templeterrace.com. EOE/DFWP

CITY OF WINTER GARDEN – POSITIONS AVAILABLE The City of Winter Garden is currently accepting applications for the following positions: - Wastewater Plant Operator Class C - Water Plant Operator Class C - Collection Field Tech - I - Collection Field Tech II - Utilities Operator II - Customer Service Technician I Please visit our website at www.cwgdn.com for complete job descriptions and employment application. Applications may be submitted online, emailed to jobs@cwgdn.com or faxed to 407-8772795.

We are currently accepting employment applications for the following positions: Water & Wastewater Licensed Operator’s – positions are available in the following counties: Pasco, Polk, Highlands, Lee Instrumentation Technician – Pasco Maintenance Technicians – positions are available in the following locations: Jacksonville, Lake, Marion, Ocala and Palatka

AECOM is recruiting for a Project Engineer position in the Fort Myers, Florida office. Candidate must have a minimum of BSCE and be licensed and/or registered as professional engineer in Florida with 5-10 years of experience. Preferred Qualifications: Experience on pipe network modeling, pump station hydraulics, civil/mechanical design, water and wastewater treatment facilities, preparation of design drawings and technical specifications, and technical writing; Participation in professional organizations is strongly encouraged; Must have strong verbal and written communication skills. For more details and to apply online: www.www.aecom.com/Careers by indicating 90605BR: Project Engineer.

Employment is available for F/T, P/T and Subcontract opportunities Please visit our website at www.uswatercorp.com (Employment application is available in our website) 4939 Cross Bayou Blvd. New Port Richey, FL 34652 Toll Free: 1-866-753-8292 Fax: (727) 848-7701 E-Mail: hr@uswatercorp.com

Water and Wastewater Utility Operations, Maintenance, Engineering, Management

Florida Water Resources Journal • January 2014

Utilities Treatment Plant Operators & Trainees $41,138-$57,885/yr plus $50/biweekly for “B” lic.; 100/biweekly for “A” lic. Class “C” FL Operator Lic. required. Accepting unlicensed applicants also, $37K. Apply: HR Dept., 100 W. Atlantic Blvd., Pompano Beach, FL 33060. Open until filled. E/O/E. Visit http://pompanobeachfl.gov for details.

Utility Operations Superintendent City of Fernandina Beach The City of Fernandina Beach is seeking a Utility Operations Superintendent to oversee the operations, maintenance, and construction for the City’s sewer system located on Amelia Island. It requires a Florida State Class B Wastewater Operators license, CDL Class B Florida Driver’s License with tanker endorsement and 10 years progressive supervisory experience in Utility operations. Salary range is $45,018 to $70,903. Interested candidates can apply on the City of Fernandina Beach’s web site at http://www.fbfl.us

Town of Lake Placid, Florida Director of Utilities Civil Engineering Degree or Finance Degree preferred. Experience in managing and operating water and wastewater systems required. Experience in financial issues involving the management, operation and acquisition of utilities is required. Prefer that applicant have at least a Florida dual “C” Certification in water and wastewater treatment or ability to obtain within three months of hire. Interested parties may mail resumes to Town Administrator by email at lakeplacidinfo@gmail.com, 311 W. Interlake Blvd, Lake Placid, FL 33852. Download job description and emp. application from website at: www.lakeplacidfl.net. EOE/DFWP.

Utility Systems Manager - Pembroke Pines, FL U.S. Water Services Corporation is accepting applications for a full time Utility Systems Manager position in the City of Pembroke Pines Operation. MANAGER CHARACTERISTICS: This is a management position responsible for supervising and managing the operation of assigned utility systems and requires ability to exercise professional judgment and discretion in directing employees. The ability to work well with others and solve complex problems with minimal supervision while adhering to company policies and procedures is also required. Confident presence is necessary when addressing a Private, Municipal, or other Government entities either directly, or within Council or Owner Board Meetings. Understanding fiscal contract management is required.

January 2014 • Florida Water Resources Journal

QUALIFICATION REQUIREMENTS: 1. Possess experience in the Water and Wastewater Utility Service Industry as a Total Utility System Manager (Utility Operations, Maintenance, Distribution and Collection Management, with Customer Service oversight). 2. Minimum five years of successful hands on experience in utility operations as a system operator. 3. Completion of special educational programs related to supervisory and management techniques is preferred. 4. Dual Water and Wastewater Certifications Preferred. Licenses & Certificates: 1. Possess a valid Florida Class C driver's license in compliance with adopted Company driving standards. 2. Possess Dual State Water and Wastewater Treatment Operator Certificates. Knowledge of: 1. The operation and maintenance of pumps, motors, pressure regulation equipment, chemical feed equipment and electronic automatic control systems. 2. Applicable City, State and Federal codes regarding utility system operation and maintenance. 3. Administrative principles and methods, including goal setting, program development, scheduling, budget preparation and administration, cost containment and employee supervision. 4. Principles, practices, and techniques of municipal public works functions, including water and wastewater activities. Skill in: 1. Supervising, training, motivating and evaluating staff. 2. Exercising sound independent judgment within established guidelines. 3. Organizing work, setting priorities, meeting critical deadlines and completing assignments with minimal supervision. 4. Exercising resourcefulness in meeting and resolving problems. 5. Representing the Company effectively in meetings with others. 6. Use of common office software including Microsoft Office. 7. Managing Budgets, Job Costing and Profitability. For a complete job description, please visit our website at www.uswatercorp.com U.S. Water offers a competitive compensation and benefits package along with a strong growth-oriented working environment. SALARY: The Salary Range for this position will be $90,000-$105,000.

United States Sugar Corp Clewiston Florida is accepting applications for State Certified Water operators. All applicants must hold a minimum of a Class C WTP license as issued by the State of Florida. Current Pay scale: C – $ 19.70 B – $ 22.88 A – $ 24.15 Email your resume to Jdooley@ussugar.com OR Apply online at www.ussugar.com

Positions Wanted Shop Mechanics and Field Service Tech Wanted Manufactures repair and service facility is looking for quality people in the Orlando and Tampa area. Shop mechanics: Must be experienced in pumps and motors repairs, minimum. Field Service Tech: Must be experience in pumps, lift stations and control panels. Must have a valid driver’s license and know how to operate the Autocrane on the truck. Excellent benefit package with employee medical paid, 401K, vacations and holidays. Equal Opportunity Employer. Please send resumes to tim@hydraservice.net or fax to 407-330-3404

THOMAS WIERDA – Holds a Florida C Wastewater license and is seeking a part time position in a package or regular plant. Prefers southwest Florida, Lee, Collier or Charlotte counties. Contact at 1786 Emerald Cove Circle, Cape Coral, Fl. 33991. 239-462-4085 STANFORD KNIGHT – Holds a Florida C Wastewater and C Water license with 10 years experience. Prefers the central Florida area but is willing to relocate. Contact at 1030 NW 118th St, Miami, Fl. 33168. 786-439-7317 BRIAN WEIGHTMAN – Has passed his C Water and Wastewater courses and needs additional plant time. Has also taken Advanced & Industrial Wastewater 1 & 2. Proficient in Chemistry and Math(Teaches classes in these subjects). Prefers central Florida and east coast area and is willing to relocate. Contact at 1363 Wayne Ave., New Smyrna Beach, Fl. 32168. 386-478-9942 DARYL BROWN – Holds a Florida B Wastewater and C Water license with six years experience. Prefers the Orlando, Winter Park or Winter Garden area of the state. Contact at 5445 Limelight Circle, Orlando, Fl. 32839. 407-692-3333

Certification Boulevard Answer Key From page 59 1. C) Rotifer Beginning with the lowest life form, the microorganism indicators are amoebas, small flagellates, large flagellates, free swimming ciliates, stalk ciliates, rotifers, nematodes (worms) and water bears. So, of the three indicators listed in the question, the rotifer is the highest life form in the activated sludge process.

2. A) 19.3 lbs/day/ft2 Formula Total lbs per day entering the secondary clarifier ÷ Total clarifier surface area in ft2 Total lbs per day entering the secondary clarifier = (5.5 mgd + 2.75 mgd) x 2,200 mg/L x 8.34 lbs/gal = 151,371 lbs per day Clarifier surface area = 3.14 x (50 ft x 50 ft) = 7,850 ft2 = 151,371 lbs per day ÷ 7,850 ft2 = 19.28 lbs per day per ft2

3. B) A strong influent waste strength. The term “loading” refers to the demand for oxygen placed on the activated sludge process from the flow being treated. A shock load is a high demand for oxygen (from CBOD5, COD or nitrogen) placed on the activated sludge process in a short period of time.

4. C) Low aeration DO Because denitrification is an anoxic reaction, low dissolved oxygen levels in the aeration tank will typically result in the best denitrification efficiency.

5. B) Fermentation The fermentation zone of a Bardenpho process receives raw wastewater (usually after

preliminary treatment) and return activated sludge (from secondary clarifiers). The MLSS is mixed and not aerated in the fermentation zone for a time period of about 1 to 3 hours. This zone, absent of all sources of oxygen, basically activates a group of phosphorus accumulating organisms (PAO), which trade phosphorus for CBOD5. These bugs release phosphorus from their cells and “grab onto” food for later decomposition. A successful fermentation zone will have phosphorus levels in the outlet about two to four times higher than the inlet to the tank.

9. A) 7.2 lbs Nitrification consumes alkalinity at the rate of about 7.2 lbs of alkalinity for each lb of ammonia oxidized. Because this action causes the mixed liquor pH to drop, biological denitrification is desirable, which replenishes the alkalinity at a rate of about 3.6 lbs of alkalinity for each lb of nitrate that is consumed as a source of oxygen. The action of denitrification helps to stabilize the MLSS pH in a range acceptable to the nitrifying bacteria.

10. D) Decrease the RAS rate.

6. C) Autotrophic There are two main groups of autotrophic bacteria that are responsible for the conversion of inorganic ammonia to nitrate. The first group, called nitrosomonas (known as ammoniaoxidizing bacteria), convert ammonia to nitrite. The second group, called nitrobacter (known as nitrite-oxidizing bacteria), convert nitrite to nitrate. The process of nitrification does not necessarily remove nitrogen from the wastewater; it only converts it to a more stable form.

7. D) Endogenous respiration Endogenous respiration takes place when the sludge is very old and food availability is very low (low F/M ratio, high SRT). This condition encourages active bacteria still hungry to “cannibalize” other bacteria to find and assimilate their uneaten food (carbon) value. Endogenous respiration is known as “survival of the fittest,” and is on the far right side of the growth curve.

8. A) Heterotrophic Facultative heterotrophic bacteria are responsible for the conversion of nitrate (NO3) to free nitrogen gas (N2) in the absence of dissolved oxygen. This activity, called denitrification, consumes some CBOD5 in the process.

The total flow entering an aeration tank is Q plus QR (influent flow plus RAS flow). As the RAS flow is decreased, the contact time through the aeration tank zones is increased, due to a reduction of the total flow entering the aeration tank.

Columnist note: Hubert H. Barnes, P.E., maintenance superintendent for the City of Hollywood Wastewater Treatment Plant, submitted the following comment concerning question 8 in this column in the November 2013 issue of the Journal. The question and answer were related to cavitation of a high-service water pump. It is insufficient to say that “This drop in pressure causes gas pockets to form in the water, which then collapse” without explanation that the “gas” is actually water vapors, and that they collapse as the pump imparts pressure energy to overcome the vapor pressure of the fluid. We are talking about a high-service pump, and therefore take it that there are no volatile gases trapped in the water. The answer also stated that “This can occur when a pump is trying to deliver more water that it was designed for.” Pumps do not try to do anything; they simply react to the suction and discharge conditions. Thank you, Hubert, for your comments and for reading Certification Boulevard. Your response may help other readers who may have been confused about the explanation to that question. Roy

Florida Water Resources Journal • January 2014

Display Advertiser Index Arcadis ....................................................78 Blue Planet ..............................................15 CEU Challenge ..........................................49 CROM ......................................................57 Data Flow ................................................41 FSAWWA Drop Savers ..............................40 FSAWWA Legislation Day ..........................68 FSAWWA Operator Awards........................47 FSAWWA Training ....................................61 FWEA Collection System ..........................71

FWPCOA Short School ..............................67 FWPCOA Training ......................................53 Florida Water Resources Conference ..23-28 Garney........................................................5 Gerber Pumps E.C.....................................21 GML Coatings ......................................45,66 Hudson Pumps ........................................35 ISA............................................................78 McKim & Creed ........................................13 Oldcastle ..................................................69

Polston................................................10-11 Rangeline ................................................79 Regional Engineering ................................48 Reiss Rngineering ....................................31 Stacon ........................................................2 Stantec ....................................................71 Treeo ........................................................20 US Water ..................................................43 Wade Trim ................................................70 Xylem ......................................................80

Editorial Calendar January . . .Wastewater Treatment February . . .Water Supply; . . . . . . . . . .Alternative Sources March . . . . .Energy Efficiency; . . . . . . . . . .Environmental Stewardship April . . . . . .Conservation and Reuse; . . . . . . . . . .Florida Water Resources . . . . . . . . . .Conference May . . . . . . .Operations and Utilities Management June . . . . . .Biosolids Management and Bioenergy Production; . . . . . . . . . .FWRC Review July . . . . . .Stormwater Management; . . . . . . . . . .Emerging Technologies August . . . .Disinfection; Water Quality September .Emerging Issues; . . . . . . . . . .Water Resources Management October . . .New Facilities, Expansions and Upgrades November .Water Treatment December .Distribution and Collection Technical articles are usually scheduled several months in advance and are due 60 days before the issue month (for example, January 1 for the March issue). The closing date for display ad and directory card reservations, notices, announcements, upcoming events, and everything else including classified ads, is 30 days before the issue month (for example, September 1 for the October issue). For further information on submittal requirements, guidelines for writers, advertising rates and conditions, and ad dimensions, as well as the most recent notices, announcements, and classified advertisements, go to www.fwrj.com or call 352-241-6006.

January 2014 â&#x20AC;˘ Florida Water Resources Journal