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TECHNICAL ARTICLES 4 Comparing Aluminum and Iron Coagulants to Remove Organic Carbon, Color, and Turbidity from a Florida Slough—David T. Yonge and Steven Duranceau
12 Engineered Biofiltration for Drinking Water Treatment: Optimizing Strategies to Enhance Performance—Jennifer Nyfennegger, Chance Lauderdale, Jess Brown, and Kara Scheitlin
28 Bench-Scale Evaluation of Chlorine-Ammonia Process for Bromate Control During Ozonation—Hongxia Lei, Dustin W. Bales, and Jon S. Docs 38 Dynamic Operation of Ultrafiltration Membranes for Potable Water Production—Christopher C. Boyd and Steven J. Duranceau
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Volume 65
ON THE COVER—An aerial view of the water treatment facilities at the North Springs Improvement District in Coral Springs. (photo: Michael Gardner)
November 2013
Number 11
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.
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Florida Water Resources Journal • November 2013
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Comparing Aluminum and Iron Coagulants to Remove Organic Carbon, Color, and Turbidity from a Florida Slough David T. Yonge and Steven Duranceau isinfection has been used to treat pathogenic microorganisms in the United States since 1908 (Environmental Protection Agency, 1999). Disinfectants such as chlorine and ozone are highly reactive chemicals, making them efficient for inactivating pathogens. In the mid-70s however, chemists in Rotterdam discovered that four trihalomethanes were observed to increase following chlorination of a surface water supply (Rook, 1974). In more recent times, ozone and other disinfectants have been shown to react with natural organic matter to form disinfection byproducts, or DBPs (Van Leeuwen, 2000; Kim Mi Hyung, 2005; Edzwald, 2011). Under the Stage 1 Disinfectants/Disinfection Byproducts Rule (D/DBPR), the U.S. Environmental Protection Agency (EPA) has regulated some DBPs such as trihalomethanes (THMs) and haloacetic acids, or HAAs (Lovins, Duranceau, Gonzalez, & Taylor, 2003). Strategies to maintain DBP rule compliance include either altering the disinfectant or removing the precursor matter. Efforts that focus on postformation treatment are limited to chloroform, which is a semivolatile DBP that can, under certain conditions, be removed by stripping; however, this approach is limiting and does not address nonvolatile DBPs. Natural organic matter (NOM) refers to complex organic chemicals present in natural waters originating from biological activity, decaying organic matter, excretions from aquatic organisms, and runoff from land (Crittenden, Trussell, Hand, Howe, & Tchobanoglous, 2005). It is of particular concern in drinking water treatment for both its effect on the aesthetic quality of the water and the fact that NOM serves as a surrogate for DBP precursors. In drinking water treatment, NOM and DBP precursors are often quantified by measuring the total organic carbon (TOC) or dissolved organic carbon (DOC), which is typically nonpurgeable (Wallace Brian, 2002). Although most groundwater has TOC concentrations less than 2 mg/L, surface water typically ranges from 1-20 mg/L. Swamps and highly colored surface water may have TOC
D
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concentrations as high as 200 mg/L (Crittenden et al., 2005). A common surface water treatment method for NOM removal includes coagulation, flocculation, sedimentation, and filtration (Crittenden et al., 2005).
Objective The research for this article was conducted by the University of Central Florida (UCF) to assist Carollo Engineers with its efforts in the development of the Dona Bay Watershed Management Plan for Sarasota County and the Southwest Florida Water Management District (SWFWMD). Carollo Engineers identified six overall treatment objectives needed to achieve the treatment goals for the source water and meet drinking water standards. The overall objectives include treatment goals for total solids, natural organics, total dissolved solids (TDS), hardness, hydrogen sulfide (H2S), synthetic organic compounds (SOCs), methyl-isoborneal (MIB), geosmin, iron, and manganese, and included disinfection evaluations (Carollo Engineers Inc., 2012). Iron and manganese control will be used to achieve possible odor and color treatment goals. Some form of stripping or aeration may be implemented to address odor concerns caused by H2S if surrounding wells were to be incorporated as alternative sources to the Cow Pen Slough (CPS) overland flow. Solids and organics removal were critical in order to account for turbidity, TOC, and color issues. The primary objective of research conducted by UCF’s civil, environmental, and construction engineering (CECE) department was to conduct coagulant selection in support of the overall project by assessing the treatability of turbidity, color, and TOC through a bench-scale jar testing evaluation of conventional treatment. Information regarding coagulant dosages, type, optimum pH ranges, and percent removals were studied to compare the effectiveness of traditional coagulants with two coagulants less established in treating Florida surface water. Iron-based coagulants have often been used in conventional Florida drinking water plants and, although effective
November 2013 • Florida Water Resources Journal
David T. Yonge, E.I. is a graduate student at the University of Central Florida in Orlando pursuing his doctorate in environmental engineering specializing in drinking water treatment and Steven J. Duranceau, Ph.D., P.E. is associate professor of environmental engineering in the civil, environmental, and construction engineering department at the University of Central Florida.
at removing organics, they can also add undesired color to the water. Aluminum sulfate provides a clear color alternative to the ferric based coagulants, but can add chemical costs due to the likely need for postcoagulation pH adjustment. Both aluminum chlorohydrate (ACH) and poly aluminum chloride (PACl) are advanced cationic and colorless chemicals designed to effectively treat industrial, municipal, and wastewaters at pH values near neutral, but have not previously been tested extensively on highly organic Florida surface water.
Raw Water Quality The CPS is a man-made canal in the Dona Bay watershed located along the western coastal region of central Florida in Sarasota County. The CPS is one of three main tributaries contributing to the Dona Bay. The water in the slough flows south and eventually converges with Fox Creek and Salt Creek before flowing into the Shakett Creek, and ultimately, Dona Bay. The CPS was originally constructed in 1966 as a drainage system for flood protection in the Myakka River basin (SWFWMD, 2009). Historical rainfall and stream flow data for the CPS describe flows ranging from 0 to 2,000 cu ft per sec (cfs), indicating widely variable and flashy flows corresponding to rainfall events. The size of the contributing catchment for the CPS is approximately 35,380 acres. Land-use data from the SWFWMD for the CPS basin is categorized into seven classes. The Continued on page 6
Figure 1. Photographic Comparison of the Cow Pen Slough Continued from page 4 data indicates that the CPS basin is dominated by agricultural and urban land use. The natural organic content of Florida surface water is typically high, with TOC values often greater than 15 mg/L and true color values as high as 700 platinum-cobalt units (PCU). The water quality in the CPS is representative of typical Florida surface water. Water from the CPS contains high amounts of natural organic carbon, color, and suspended solids. The presence of trace levels of organic contaminants were found that included insecticides, herbicides, and petroleum hydrocarbons. Because the majority of the slough is bordered by fertilized agricultural lands, nu-
trient runoff from sheet flow over the agricultural lands has been observed during periods of heavy rainfall. Visual observations indicated that leaching of excess nitrates and phosphates from surrounding lands had caused algae blooms and nitrogen concentrations to spike within the slough. Figure 1 provides photographs taken during average conditions (left) and during a eutrophic event (right). Table 1 compares the values from historical data to the values obtained during the 2012 UCF treatability study. Many of the 2012 values fall within the range of the historical data taken over the years 1963-2011. More recent data collected in 2012 indicated that DOC, sodium, strontium, TOC, and total sus-
Table 1. Comparison of Historical and UCF Raw Water Quality
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pended solids (TSS) had increased over time. This was not surprising as there were less than 30 historical samples taken for carbon and metals analyses. The maximum values for TSS corresponded to a eutrophic event; these numbers are shown in Figure 2. Because the historical data makes no mention of eutrophic events that cause increases in algae concentrations, it is possible that in the past samples were not taken for TSS during such occurrences.
Methods and Materials Approach Jar testing is considered to be an acceptable and economical method for simulating a full-scale coagulation, flocculation, and sedimentation (CFS) basin and was chosen to determine the effectiveness of each coagulant. For the purpose of this study, effectiveness was evaluated based on the removal efficiency of organics, color, and turbidity. Organic content was measured in terms of nonpurgeable dissolved organic carbon (NPDOC; herein after referred to as DOC) which assumes filtration will be implemented after the sedimentation process, and is defined as the fraction of organic carbon remaining that has the potential to act as a DPB precursor. The CFS removal efficiency is a function of many parameters, including mixing intensity, mixing times, chemical addition, pH, temperature, etc. Variables such as mixing intensity and mixing times were held constant and did not change during the study. Coagulant concentrations ranged from 80 mg/L to 240 mg/L and were increased in increments of 20 mg/L for each coagulant. The established effective testing range for pH was 4.0 to 8.0 and pH was measured in increments of 0.5 pH units. By varying pH and coagulant concen-
trations, effective removals were determined for a wide range of concentrations and pH values. Table 2 provides descriptions of the five coagulants under investigation. Procedures Raw field samples were collected from a sampling bridge by repetitively lowering 5-gal buckets from the bridge into the slough. Raw samples were transferred into 15-gal drums for transportation and storage. Field parameters, including turbidity, pH, temperature, and conductivity, were measured on site during sampling and 1-L amber sample bottles were filled for laboratory analyses for each drum. Titrations curves were developed on the raw water to determine the appropriate volume and normality of pH adjusting chemicals, which were necessary to obtain the target pH values for each coagulant dose. After determining the appropriate caustic or acid dosages for each coagulant dose, coagulant concentrations could be varied and interference from varying pH and temperature values could be minimized. The jar testing equipment was programmed using the American Society for Testing and Materials (ASTM) standard jar testing sequence of 120 revolutions per min (rpm) for 1 min, 50 rpm for 20 min, and 0 rpm for 15 min (ASTM, 2003). The proper volume of coagulant and corresponding caustic or acid volume was measured and delivered onto septas using a pipette. To minimize variation among coagulated samples and obtain equal reaction times, the septas were simultaneously dropped into the jars once the jar testing sequence was initiated. During the flocculation stage of jar testing, the pH and temperature were recorded. At the end of the settling period, 450 mL of each settled sample was collected and tested for turbidity and filtered for DOC and color analysis. Extensive field and laboratory quality control measures were taken throughout this study. To assess the consistency of the precision of the analytical instrumentation, duplicate measurements were taken. For field measurements, duplicates were taken every six samples. During the bench-scale testing, duplicates were prepared for each jar test run, as well as for each metal and anion analyses. To assess the consistency of the accuracy of the TOC analyzer, one out of every five samples was spiked with 1 mL of 200 parts per mil (ppm) TOC solution created monthly for DOC analysis. Quality control requirements for field data were followed according to the analytical methods listed in the laboratory quality assurance procedures for the UCF Environmental Systems Engineering Institute (ESEI) housed within the CECE department
Table 2. List of Coagulants
Table 3. Summary of Data
(Real-Robert, 2011). Quality control measures for laboratory data collection were performed according to the Standard Methods for the Examination of Water and Wastewater (Eaton, Clesceri, Rice, & Greenberg, 2005) and EPA’s Handbook of Analytical Quality Control in Water and Wastewater Laboratories.
Results Ferric Chloride The maximum removal obtained using ferric chloride was 89 percent, yielding a treated water DOC concentration of 2.90 mg/L. Consistent DOC removals of 80 percent were observed in the ferric chloride concentration range of 100 to 240 mg/L. This broad variation in ferric chloride concentration suggests that there is a low correlation between coagulant dose and the removal efficiency. Consistent DOC removals of 80 percent were observed within the pH range of 4.0 to 5.0. This narrow range of pH suggested a correlation between pH and DOC removal efficiency. Color removal appears correlated to the DOC removals achieving higher removals at lower pH values. Final color readings varied from 21 PCU to < 5 PCU, with an average value of 8 PCU achieving the maximum containment level goal (MCLG) of 15 PCU. Ferric Sulfate The DOC removals between 60 and 65 percent were achieved at concentrations as low as 80 mg/L with treatment using ferric sulfate. Doubling the dosage to 160 mg/L was required
to reach the maximum DOC percent removal of 71 percent. Ferric sulfate does show a similar correlation to that of ferric chloride at pH values above 5.5, in that increasing the pH caused a decrease in DOC removals. However, unlike ferric chloride, at pH values above 6.5, increasing the ferric sulfate dosages did not produce a significant response in DOC removals. Only a 10 percent increase in DOC removal was achieved by raising the pH above 6.5. The maximum DOC removal was 71 percent and resulted in a final DOC concentration of approximately 3.5 mg/L. The required coagulant concentration of ferric sulfate is 50 percent higher and removed nearly 15 percent less DOC than that of ferric chloride. Ferric sulfate was also less effective for color treatment as only 16 percent of the samples achieved the MCLG of 12 PCU. Aluminum Sulfate Aluminum sulfate correlates well with the ferric sulfate results, even though the optimum pH and coagulant ranges are more constrained. Only at a pH range of 4.5 to 5.5 and by dosing alum to a concentration of 180 mg/L was a 55 percent removal of DOC observed. At 55 percent removal, final DOC values ranged from 5.5 to 7.5 mg/L. At pH values higher than 6.5, increasing the alum concentration has little effect on DOC percent removals, yielding the lowest DOC removals relative to the other coagulants. However, on average, alum was 82 percent efficient at removing color, yielding 95 percent of the values below 12 PCU. Continued on page 8
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Continued from page 7
Discussion
Poly Aluminum Hydroxychloride The PACl achieved similar DOC removals to alum ranging from the lower 60s to the lower 20s, but with a less constrained effective pH range of 4.0 to 5.5. The DOC removals in the lower 50 percent range were observed at PACl concentrations of 100 mg/L, with a maximum DOC removal of 61 percent at 240 mg/L. Raw water DOC values were 16 mg/L for the jar tests conducted using PACl. PostCFS DOC values were observed as low as 5.29 mg/L. Color removal was relatively high as compared to the other coagulants, with an average value of 71 percent. Turbidity removals ranged from 30 to 60 percent in the pH range of 4.0 and 5.5. Aluminum Chlorohydrate Aluminum chlorohydrate achieved consistent DOC removals of over 60 percent within a pH range of 6.0 to 7.0. A strong correlation between pH and DOC removal exists with ACH, while ACH concentration seems to have a minimal effect on overall DOC removal. Removals from 60 to 70 percent were observed at nearly neutral pH and ACH dosages of 80 mg/L. The raw water DOC concentration within these ranges was 30 mg/L. Maximum DOC removals were observed in the lower 80s, with post-CFS DOC readings ranging between 5 and 6 mg/L. The ACH effectively removed color, with 33 percent of the samples showing color values under 5 PCU and 80 percent of the values meeting the MCLG of â&#x2030;¤12 PCU. The ACH achieved an average turbidity removal of 46 percent within this pH range. Table 3 provides the ranges for each coagulant dose observed to obtain optimal removals of DOC, color, and turbidity.
Due to the variability in raw water quality over time it is necessary to consider the water quality at the particular date of sampling. The sampled raw water contained DOC concentrations ranging from 10 mg/L to 30 mg/L and color units ranging from 28 PCU to 275 PCU. It was observed that ferric-based coagulants were less effective for removing turbidity, oftentimes adding to the turbidity of the water, whereas aluminum-based coagulants (specifically PACl and ACH) proved effective at decreasing turbidity. The data collected during this study indicate that the water quality of the CPS is poor relative to other Florida surface water. Organic content in the CPS was found to be generally high, with TOC values averaging above the typical surface water range of 1 to 20 mg/L. Oftentimes the TOC concentration was 50 percent higher than representative Florida surface water, reaching concentrations over 30 mg/L. Raw turbidity concentrations over 5 nephelometric turbidity units (NTU) were consistently observed, with turbidity spikes as high as 23 NTU. Additionally, field observations revealed that the apparent color of the water was dark. True color values in the CPS ranged from 30 to 280 PCU, reflecting characteristics of swamplike waters. At least one instance of an algae bloom was observed. Each of these factors suggested that the water would be difficult to treat. The factors that appear to have contributed to the poor quality of water include the surrounding land use and the variable environmental conditions. The CPS was originally designed as a drainage system for flood protection and consequentially contains high amounts of debris, vegetation, suspended
solids, color, and organic content. The CPS catchment mainly consists of land classified as agricultural, urban, and nonforested wetland. The occurrences of algae blooms in the CPS suggest agricultural and urban runoff has had a negative effect on the water quality of the slough. From the bench-scale jar testing evaluation, the MCLGs and maximum containment levels (MCLs) for turbidity and organics removal were not attainable with the use of CFS alone. For example, the lowest turbidity achieved after CFS was 0.49 NTU and the MCLG for turbidity was 0.3 NTU. Therefore, traditional filtration techniques or membrane filtration may need to be supplemented to meet EPA regulations. Specifically the results of the jar testing evaluation indicated that ferric chloride and ACH were the most effective coagulants at DOC and color removal at the lowest dose concentrations. Ferric sulfate was effective at DOC removal but required a higher concentration of coagulant and was the least effective coagulant at removing color depicted in Figure 2. The traditional iron-based coagulants and alum had low turbidity removals and they were often observed to add turbidity to the water. The PACl and ACH had similar percent removals for color and turbidity achieving consistent percent removals of 95 percent and 45 percent, but PACl was less effective than ACH at removing organics. Alum was the least effective at removing organics and was the second least effective coagulant for removing color. This study of nontraditional coagulant performance revealed that ACH was more efficient at removing DOC, color, and turbidity under the conditions tested in this evaluation than the other coagulants evaluated.
Acknowledgements
Figure 2. Coagulant Comparison Chart
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The information presented in this article was but one component of a larger research project funded cooperatively by Sarasota County Government (1001 Sarasota Center Blvd., Sarasota, Fla. 34240) and the Southwest Florida Water Management District (SWFWMD, 2379 Broad Street, Brooksville, Fla. 34604-6899). Carollo Engineers Inc. (401 N. Cattleman Rd., Suite 306, Sarasota, Fla. 34232) was selected by Sarasota County and SWFWMD to perform a treatability analysis to develop, analyze, and integrate treatment alternatives for a new water supply; in that effort, Carollo Engineers retained the CECE department at UCF through Agreement 16208093 to conduct coagulant selection research in support of the overall project. The authors are grateful to the contribu-
tions and assistance of UCF students Paul Biscardi, Christopher Boyd, Alyssa Filippi, Genesis Rios, Jennifer Roque, Nick Webber, and Jayapregasham Tharamapalan. The authors wish to acknowledge the efforts of Maria RealRobert, CECE’s laboratory coordinator, for her limitless assistance. The contents herein do not necessarily reflect the views and policies of the sponsors, nor does the mention of trade names or commercial products constitute endorsement or recommendation. The comments and opinions expressed herein may not necessarily reflect the views of the officers, directors, affiliates, or agents of Sarasota County Government, SWFWMD, Carollo Engineers, and the University of Central Florida.
References • Amirtharajah A., M. K. (1982). Rapid-mix Desigh for Mechanisms of Alum Coagulation. AWWA, 74(4), 210-216. • ASTM. (2003). Standard Practice for Coagulation-Flocculation Jar Test of Water. ASTM International, D2035-80. • Carollo Engineers, Inc. (2012). Treatability Analysis for Cow Pen Slough and Intermediate Aquifer Water Sources - Technical Memorandum No.5. Sarasota.
• Crittenden, J., Trussell, R. R., Hand, D., Howe, K., & Tchobanoglous, G. (2005). MWH's Water Treatment: Principles and Design. New Jersey: John Wiley & Sons Inc. • Eaton, A., Clesceri, L., Rice, E., & Greenberg, A. (2005). Standard Methods for the Examination of Water and Wastewater (21 ed.). Washington: American Public Health Association, American Water Works Association, Water Environment Federation. • Edzwald, J. (2011). Water Quality and Treatment: A Handbook on Drinking Water. Denver: McGraw-Hill. • Environmental Protection Agency. (1999). 25 Years of the Safe Drinking Water Act: History and Trends. Rockville, MD: U.S. Environmental Protection Agency: EPA Publication No. 816-R-99-007. • Kabsch-Korbutowicz, M. (2006). Impact of Pre-coagulation on Ultrafiltration Process Performance. Desalination, 232-238. • Kim Mi Hyung, Y. M. (2005). Characterization of NOM in the Han River and Evaluation of Treatability Using UF-NF Membrane. Environmental Research, 116123. • Lovins, W. A., Duranceau, S. J., Gonzalez, R. M., & Taylor, J. S. (2003). Optimized coagulation assesment for a highly organic surface
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water supply. American Water Works Association, 94-108. Real-Robert, M. (2011). Environmental Engineering Laboratories: Quality Assurance/Quality Control. Orlando: University of Central Florida - Department of Civil, Environmental, and Construction Engineering. Rook, J. (1974). Formation of Haloforms During Chlorination of Natural Waters. Water Treatment and Examination, 23(2), 234-243. SWFWMD. (2009). Proposed Minimum Flows and Levels for Dona Bay/Shakett Creek below Cow Pen Slough. Sarasota. Van Leeuwen, F. (2000). Safe Drinking Water: the Toxicologist's Approach. Food and Chemical Toxicology, 38, 51-58. Wallace Brian, P. M. (2002). Total Organic Carbon Analysis as a Precursor to Disinfection Byproducts in Potable Water: Oxidation Technique Considerations. Journal of Environmental Monitoring, 35-42.
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Florida Department of Environmental Protection Provides Drinking Water Information; Seeks Input from Permit and License Holders Making up approximately 75 percent of the human body, water is an essential component of life, carrying oxygen through the blood and providing nutrients to cells, while flushing waste out of the body. In order to supply water to the 19 million
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Florida residents who obtain their drinking water from public supply water systems, the state’s 6,326 drinking water facilities must treat raw water to meet health and safety standards. These systems are permitted to utilize approximately 6,566 mil gal per day of raw water
November 2013 • Florida Water Resources Journal
to generate potable water for Florida’s residents and visitors. Raw water comes from three sources: surface water, shallow ground water (surficial aquifer), and deep ground water (Floridan Aquifer). Surface water is mostly rain-driven and contains stormwater runoff. The water is mainly collected in a stream, river, reservoir, canal, lake, or wetland. Because its water quality is the most variable, it requires specialized treatment in order to meet health standards for drinking water. Clear Lake, for example, is fed through a series of canals and a local environmental preserve and is the water source for West Palm Beach. Surficial aquifers can reach up to 400 ft in depth and are one of Florida’s freshwater sources. The freshwater is separated from the Floridan Aquifer by shallow beds of sea shells or soil that are not permeable to water. The Biscayne Aquifer, for example, is the primary source of water for all of Dade and Broward counties, as well as the southern portion of Palm Beach County. The Floridan Aquifer—a deep aquifer that is part of the principal artesian aquifer system—produces brackish water, which requires more treatment than any other source. It is one of the most productive aquifers in the world and provides water for hundreds of thousands of people in Tallahassee, Orlando, Jacksonville, and St. Petersburg, as well as parts of Georgia. While each source of raw water requires treatment, the method of treatment varies by facility. It can range from simple disinfection by injecting chlorine into the raw water, all the way to the use of filtration, sedimentation, coagulation, pH control, corrosion inhibition, and ultimately, reverse osmosis. In order to assist Florida’s water treatment plants in achieving compliance with the federal and state Safe Drinking Water Acts, the
Florida Department of Environmental Protection (FDEP) provides yearly funding to build or improve domestic wastewater and drinking water facilities, to reclaim mined lands, and to implement stormwater and other nonpoint source management projects. Learn more about drinking water by visiting the Departmentâ&#x20AC;&#x2122;s website, www.dep.state.fl.us/water/drinkingwater/ index.htm, which provides resourceful information and links. Do you have a permit or license with the Florida Department of Environmental Protection? How much does it cost to get a permit or license and to comply with the terms? To help determine the economic impact regulations have on businesses, FDEP has designed a survey to capture some of that data. The survey addresses the following permits or licenses: Coastal Construction Control Line Consumptive Use Permit (CUP) Domestic Wastewater Permit Environmental Resource Permit (ERP) Industrial Water Permit Joint Coastal Permit National Pollutant Discharge Elimination System (NPDES) Stormwater Construction Generic Permit (CGP) NPDES Stormwater Multisector Generic Permit NPDES Stormwater Municipal Separate Storm Sewer System (MS4) Resource Conservation and Recovery Act (RCRA) Operating Permit RCRA Post Closure or Hazardous and Solid Waste Amendment (HSWA) Corrective Action Permit Underground Injection Control Used Oil Permit Wastewater Treatment Plant/Drinking Water Plant/ Distribution System Operator Certification If your business requires a FDEP permit, your input will serve as a valuable tool for assessing the effects of permitting on the economy. The survey, located on the FDEP business portal home page, is available at www.dep.state.fl.us/secretar y/por tal/ default.htm, or use the QR code that links to the portal.
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Engineered Biofiltration for Drinking Water Treatment: Optimizing Strategies to Enhance Performance Jennifer Nyfennegger, Chance Lauderdale, Jess Brown, and Kara Scheitlin he use of biological drinking water treatment processes for the treatment of surface water and groundwater has recently been increasing in North America. Biofiltration can simultaneously remove a wide range of dissolved organic and inorganic contaminants, while achieving particle removal goals. Organic compounds, including color and taste and odor (T&O)-causing compounds, are not only removed but also destroyed in this process. This can limit the formation of disinfection byproducts (DBPs) and lower regrowth potential in the distribution system. Operation of biofilters requires low energy input, minimal chemicals, and little waste production. Although biofiltration can provide numerous benefits, biofilter systems can be susceptible to hydraulic and water quality challenges, such as shortened runtimes, biological clogging, and breakthrough of contaminants such as T&O, manganese (Mn), and organic carbon. Drinking water biofilters are often designed and operated similarly to conventional granular media filters, and backwashing is the primary means of biofilm control. However, backwash protocols can be ineffective at restoring clean-bed headloss and preventing underdrain fouling, even with the addition of chlorine or chloramines. These disinfectants may not effectively remove extracellular polymeric substances (EPS), which are a primary foulant of biofilters (Lauderdale et al., 2011). Adding chlorine or chloramines to biofilters can also harm the biology needed for achieving water quality goals. The EPS are significant to both fouling and headloss issues because they can occupy as much as 1,000 times the void space of filter media compared to bacteria (Mauclaire et al., 2004). An alternative approach for biofilm control is to manage microbial EPS production through 1) nutrient supplementation, and/or 2) direct removal of EPS through hydrogen peroxide (H2O2) supplementation. Pilot studies, which spanned two Water Research Foundation (WRF) tailored collaboration (TC) projects (#4215 and #4346), focused on investigating enhancement strategies
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for drinking water biofilters. Pilot tests were conducted at three surface water plants in Florida and Texas. The TC project #4215, Engineered Biofiltration for Improved Hydraulic and Water Treatment Performance, identified two “engineered biofiltration” strategies (nutrient and peroxide enhancement) that provided multiple water quality and hydraulic benefits with minor implementation requirements (Lauderdale et al., 2011). The followup study, TC #4346, Optimizing Engineered Biofiltration, provided essential studies to validate, optimize, and explore these strategies to achieve sustained performance.
Background A purposefully operated biological system (i.e., engineered biofiltration) includes biological treatment objectives as important aspects of biofilter design and operation. The goal of this work is to shift the practice of biofiltration from a passive process, designed and operated around conventional filtration objectives, to an intentionally operated biological system. The studies described here include pilot-scale studies of two strategies to meet this goal: nutrient and peroxide enhancement. Nutrient Enhancement Optimal microbial growth relies on a proper balance of carbon, nitrogen, and phosphorus. The typical target ratio of assimilable carbon: ammonia-nitrogen: orthophosphatephosphorus (C:N:P) is 100:10:1 (USEPA, 1991). This molar ratio converts to a concentration ratio of 1 mg/L C: 0.117 mg/L N: 0.026 mg/L P. The biological filter feed at typical water treatment facilities has nondetectable amounts of phosphorus (<0.01 mg/L), due to removal through enhanced coagulation and/or source water limitation. This phosphorus-limiting condition can be unfavorable for biofilter operation because phosphorus is an essential nutrient to maintain a healthy microbial population. In addition, phosphorus deficiency may lead to increased microbial production of EPS, which are strongly adhe-
November 2013 • Florida Water Resources Journal
Jennifer Nyfennegger, Ph.D., P.E., is a lead technologist with Carollo Engineers Inc. in Sarasota. Chance Lauderdale, Ph.D., P.E., is a vice president with HDR in Denver. Jess Brown, Ph.D., P.E., is a vice president with Carollo Engineers in Orange County, Calif., and is the director of the Carollo Research Group. Kara Scheitlin, P.E., is a project engineer with Carollo Engineers Inc. in Dallas.
sive and may cause clogging of biofilter media or underdrains. For that reason, adding phosphorus to the biofilter feed water may improve the “type” of biogrowth in the filters to minimize clogging, decrease headloss, and maintain uniformity of flow. Peroxide Enhancement Low doses of hydrogen peroxide (≤1 mg/L) effectively oxidize and remove EPS and inactive biomass without negatively affecting the biological activity desired for water treatment. Hydrogen peroxide may also improve biofilter treatment performance by causing certain microorganisms to express oxidoreductase enzymes that produce free radicals. These free radicals can also remove EPS, as well as oxidize recalcitrant organic compounds.
Materials and Methods Pilot Biofilters Pilot studies were conducted at three surface water treatment plants (WTPs): John Kubala WTP in Arlington, Texas; Tampa Bay Regional Surface WTP in Tampa; and Bachman WTP in Dallas. Each pilot skid (Intuitech, Salt Lake City, Utah) included four parallel biofilters (6-in. diameter columns). The pilot biofilter columns contained the same media configuration as the full-scale system at the host site (Table 1). Biofilter feed (from upstream ozonation and coagulation processes) were supplied to the pilot Continued on page 14
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Table 1. Pilot Plant Setup and Operating Parameters
Continued from page 12 equipped with progressive cavity feed pumps (one dedicated pump per column) with automatic flow control. Peristaltic feed pumps allowed flow-paced chemical injection to the combined biofilter feed water for spiking contaminants, such as 2-Methylisoborneol (MIB) and Mn. Biofilter effluent was pressure-fed to a backwash water storage tank. Each pilot included a backwash system with dedicated pump and airscour system. Backwash protocols simulated that of the hosting full-scale facility. Pilot instrumentation included on-line effluent turbidimeters, flow transmitters, and pressure sensors for monitoring headloss. Each pilot was equipped with an automatic data logger, which recorded the following data every 10 min for the duration of the study: headloss, effluent turbidity, biofilter underdrain pressure, backwash underdrain pressure, filtration rate, runtime, and run volume. Chemical Feed Contaminants were spiked to the pilot biofilter feed water using a peristaltic pump and 40-L chemical tank. To promote mixing, a static mixer was located downstream of the injection point. Contaminant spiking tests were performed to characterize Mn and T&O (e.g., MIB) removal performance. Manganese spiking of the pilot biofilter feed water was performed using reagent-grade manganese chloride from Sigma Chemical (St. Louis, Mo.); the MIB (gas chromatography-grade in methanol) was also purchased from the chemical company. For testing of the enhancement strategies, nutrients or peroxide were fed to the top of the specified biofilter using dedicated peristaltic pumps supplied by 40-L chemical tanks. Phosphorus (PO4-P) supplementation was performed using NSF-60-certified 83 percent phosphoric acid. Caustic (50 percent sodium hydroxide) was used for the biofilter feed pH adjustment at Tampa Bay and Dallas. Peroxide supplementation used food-grade 3 percent hydrogen peroxide (Arlington pilot) or technical-grade 20 percent hydrogen peroxide (Tampa Bay and Dallas pilots).
Figure 1. Biofilter Pilot Process Flow Schematic
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Analytical Methods Water quality samples of the pilot biofilter feed and effluent streams were collected twice per week throughout the pilot study period. Results were used to verify operation (e.g., dosed nutrient and hydrogen peroxide concentrations) and to evaluate water treatment performance of the pilot biofilters. Analytical methods for key parameters are: Turbidity. In-line nephelometers (Hach or ThermoScientific) were used for continuous turbidity measurement of pilot filter effluents.
Hydrogen Peroxide. Hydrogen peroxide concentration of the biofilter feed water was measured on site using a CHEMets Colorimetric Hydrogen Peroxide Test Kit (Chemtech International, Media, Pa.). Total Organic Carbon (TOC) and Dissolved Organic Carbon (DOC). Both TOC and DOC were performed using Standard Method 5130B. Manganese (Mn). Total Mn measurements were performed in accordance with Standard Method 311B. Ammonia-nitrogen (NH4-N). The NH4-N measurements were performed in accordance with Standard Method 4500. Orthophosphate-phosphorus (PO4-P). The PO4-P measurements were performed in accordance with U.S. Environmental Protection Agency (USEPA) Method 300.0. 2-Methylisoborneol (MIB). The MIB analyses were performed in accordance with Standard Method 6040D. Pilot biofilter media samples from the top 6 in. of each biofilter column were collected twice per month. Each sampling event included two samples: (1) after a backwash (i.e., clean bed), and (2) at the completion of the subsequent filter run (i.e., dirty bed). The media samples were used for microbial characterization, including: Adenosine triphosphate (ATP). The ATP analysis on biofilter media was conducted using a Deposit and Surface Analysis Test Kit (LuminUltra, Fredericton, N.B.) and a luminometer (Kikkoman, Tokyo, Japan) following the manufacturer protocols. Scanning Electron Microscopy (SEM). Biofilter media samples were imaged using a JEM 6490 LV scanning electron microscope (Peabody, Mass.). EPS. Sugars from EPS polysaccharides were measured using the method described by Dubois et al. (1956).
Results and Discussion Nutrient Enhancement Studies The biofilter feed water at the pilot sites was typically phosphorus (PO4-P)-limited due to source water limitation and/or PO4-P removal through upstream coagulation processes. Nutrient enhancement of biofilters initially targeted a total (background + dosed) bioavailable C:N:P molar ratio of 100:10:1. The PO4-P and/or NH4-N were used to supplement nutrient deficiencies in select biofilters. Nutrient supplementation testing at the Arlington pilot included PO4-P supplementation (0.02 mg/L as P) to satisfy the nutrient deficiency. Multiple benefits were achieved,
Figure 2. Profiles of the Control and Nutrient-Enhanced Biofilter at Optimized pH Conditions
including improved hydraulics, water quality performance, and microbial characteristics (Lauderdale et al., 2011; Lauderdale et al., 2012): Hydraulic Performance. The PO4-P supplementation to the nutrient-enhanced biofilter feed decreased terminal headloss (at an 18-hour filter runtime) by approximately 15 percent, relative to the control biofilter. This improvement in hydraulic performance translates to energy savings and reduced chemical usage to retreat backwash water. Water Treatment. Performance was tracked across multiple parameters, including turbidity, DOC, Mn, and MIB. The PO4-P supplementation improved the removal of DOC and Mn compared to the control. The DOC removal across the filter bed was 19 percent for nutrient-enhanced biofilter compared to 11 percent for the control. Removal of background Mn was observed for both the nutrient-enhanced and control biofilters. High concentrations of Mn were also spiked to the biofilter feed (224 µg/L). Effluent Mn concentrations were nondetect (< 2.4 µg/L) for the nutrient-enhanced biofilter, whereas the control biofilter effluent averaged 25 µg/L. During simulated long-term, moderate MIB spiking to the pilot biofilter feed, mean effluent MIB concentrations remained below the T&O threshold (< 10 ng/L) for the nutrient-enhanced and control biofilters. All pilot biofilter effluent turbidities maintained compliance with the USEPA Surface Water Treatment Rule. Microbial Characteristics. Compared to the control biofilter, the nutrient-enhanced
biofilter media had lower-measured biofilter EPS concentrations (corresponding to the decrease in headloss relative to the control), 30 percent higher terminal (end of filter run) ATP concentrations (corresponding to higher biomass concentrations), and more morphological diversity and cell abundance. Follow-up nutrient enhancement studies at Tampa Bay and Dallas using PO4-P supplementation and pH adjustment of the biofilter feed water improved hydraulic performance (>18 percent decreased terminal headloss relative to the control) and had no significant effect on water treatment performance (e.g., DOC, MIB, Mn removal). Figure 2 presents example headloss and turbidity profiles for the control and PO4-P-enhanced biofilter at the optimal pH. Optimization of the biofilter feed pH (8.0 to 8.5) proved to be an important parameter to achieve hydraulic improvements at the Tampa Bay and Dallas pilots. At ambient biofilter feed pH (7.1-7.5), nutrient supplementation did not improve biofilter performance. This was unexpected due to the results of the previous study, where nutrient addition showed hydraulic and water quality improvements. One notable difference was the type of coagulant used in upstream processes (alum versus ferric). Without pH adjustment, chemical modeling suggested removal of bioavailable PO4-P by ferric hydroxide carried over from upstream flocculation/sedimentation processes prior to penetrating the media bed (Figure 3). Increasing biofilter feed pH above Continued on page 16
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Continued from page 15 the isoelectric point of the carryover floc (i.e., creating a positive surface charge) inhibits adsorption of negatively charged PO4-P onto ferric hydroxide carryover. As a result, the PO4-P stays in solution and is available for microorganisms in the filter bed. Thus, the biofilter feed pH was adjusted to approximately 8.0 at Dallas and 8.5 at Tampa Bay. This process adjustment resulted in decreased headloss across all filters at Dallas, and further improvement in the hydraulic performance of the nutrientenhanced column relative to the control at both Dallas and Tampa Bay. Peroxide Enhancement Studies The pilot studies at both the Florida and Texas utilities showed that peroxide supple-
mentation significantly improves biofilter hydraulic performance. The strategy was first identified at the Arlington pilot when biofilter terminal head loss (at 24 hours) decreased from 6.5 ft (n = 1) to an average of 2 ft (n = 6) after initiating a continuous 1 mg/L peroxide dose to the biofilter feed water (Lauderdale et al., 2011; Lauderdale et al., 2012). These results showed a promising trend and provided the basis for further study. Validation testing of the peroxide enhancement strategy was conducted by initially augmenting the peroxide biofilter feeds at Tampa Bay and Dallas with 1 mg/L of peroxide. Following preliminary confirmation of the hydraulic benefits associated with peroxide supplementation, the peroxide dose was optimized by adjusting the biofilter feed con-
Figure 3. Photo of Carryover Ferric Floc Accumulated on the Top (Feed Side) of the Biofilter
Figure 4. Average Hydraulic Performance of GAC Biofilters Supplemented With Varying Doses of Hydrogen Peroxide Relative to the Control Biofilter (No Peroxide)
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centrations to between 0.1 mg/L and 2 mg/L. At Tampa Bay, hydraulic improvements were observed for the peroxide doses tested (0.5 to 2 mg/L), as shown in Figure 4. The optimum peroxide dose was 0.75 to 1 mg/L. At these concentrations, headloss improved by an average of 25 and 27 percent, respectively, at 24-hour filter runtimes. Algae growth was also inhibited by peroxide addition, as illustrated in Figure 5. Peroxide feed robustness tests showed that hydraulic performance improved during a period of “overfeeding” peroxide (10 mg/L), and hydraulic performance degraded to match control biofilter headloss trends when a peroxide feed failure was simulated. Effluent water quality (e.g., DOC, turbidity, Mn, and MIB) from the peroxide-enhanced biofilter was similar to the control at all peroxide doses tested. The peroxide dose that provided the best hydraulic improvement at the lowest cost differed for Tampa Bay (0.75 mg/L) and Dallas, where a 0.1 mg/L peroxide dose resulted in 33 percent lower headloss. These results demonstrate the need to evaluate and optimize peroxide feed for hydraulic improvement on a case-by-case basis, as biofilter peroxide demand is likely dependent on multiple factors, including temperature, source water, microbial ecology, and upstream treatment. Biofilter Media Type The parallel operation of anthracite and GAC media in the pilot studies provided a comparison of treatment and hydraulic performance of each media type. The nutrient and peroxide enhancement strategies improved anthracite biofilter hydraulic performance over the control GAC filters. However, anthracite biofilter water treatment performance was inferior to the GAC biofilters for both Tampa Bay and Dallas under all test conditions (e.g., control, peroxide enhancement, and nutrient enhancement). The ATP analysis of GAC media collected from the control and peroxide-supplemented biofilters showed that the peroxide supplementation (0.1 – 10 mg/L) did not significantly impact microbial activity. However, ATP concentrations in the anthracite biofilter decreased during periods of peroxide supplementation (0.5 – 2 mg/L). These results indicate that GAC may be a more robust support media to support biological growth. Pretreatment (Coagulation) Optimization Testing Pilot-scale-enhanced coagulation pretreatment optimization was performed concurrently with the biofiltration pilot at the Dallas pilot site. The pilots were tested for ho-
listic, multiprocess optimization. At coagulant doses of 60 mg/L and 30 mg/L (as Fe2(SO4)3*9H2O), results showed the same level of combined DOC removal through the coagulation and biofiltration processes. This demonstrates synergy between the coagulation and biofiltration processes. This test result also presents a significant opportunity for cost savings on chemical costs, while achieving organic carbon and DBP precursor removal goals.
Conclusions Pilot testing spanning two Water Research Foundation projects (TC #4215 and #4346) identified, validated, and optimized two “engineered biofiltration” strategies with minor implementation requirements: (1) nutrient enhancement and (2) hydrogen peroxide supplementation. These studies identified conditions that allow nutrient enhancement to be applicable across multiple water sources and treatment schemes. The pH was identified as an important parameter for biofilter nutrient optimization, which may broaden the applicability of this enhancement strategy. Pilot-scale optimization of the peroxide enhancement strategy at Tampa Bay Water and Dallas Water Utilities showed that the optimal dose for biofilter performance improvement was site-specific, indicating that biofilter peroxide demand is likely dependent on multiple factors. Optimization studies for the biofiltration process and upstream coagulation process identified a synergy between the processes. The results of this pilot-scale test showed that biofilters decreased coagulant requirements by >50 percent, while achieving organic carbon and DBP precursor removal goals. This highlights the importance of holistic, full-process evaluations for optimizing water treatment facility operation and performance.
References • Dubois, M, Gilles, K, Hamilton, J, Rebers, P, and Smith, F. 1956. Colorimetric Method for Determination of Sugars and Related Substances. Anal. Chem., 28, 3, 350. • Lauderdale, C., Brown, J., Chadik, P, Kirisits, M. 2011. Engineered Biofiltration for Enhanced Hydraulic and Water Treatment Performance. Water Research Foundation, Denver. • Lauderdale, C., Chadik, P., Kirisits, M., Brown, J. 2012. Engineered Biofiltration: Enhanced Biofilter Performance through Nutrient and Peroxide Addition. Journal American Water Works Association, 104(5), E298-E309. • Mauclaire, L., Schurmann, A., Thullner, M., Gammeter S., and Zeyer, J., 2004. Sand filtration in a water treatment plant: biological parameters responsible for clogging Journal of Water Supply: Research and Technology AQUA 53 (2) 93-108. • USEPA. 1991. Site Survey Characterization for Subsurface Remediation. EPA/625/R91/026. Office of Research and Development, Washington.
Figure 5. Photo Showing Inhibition of Algae Growth in the Biofilter Supplemented With Hydrogen Peroxide (Third Column From the Left)
Acknowledgements This work was made possible through the financial contributions of the Water Research Foundation, Tampa Bay Water, Dallas Water Utilities, and the City of Arlington. The participation of the following organizations made it possible to develop the data and analysis presented in this document: Tampa Bay Water, Dallas Water Utilities, City of Arlington Water Utilities, University of Michigan, University of Texas, Veolia Water North America, U.S. Environmental Protection Agency (USEPA) Office of Research and Development (Cincinnati, Ohio), and Carollo Engineers Inc.
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FSAWWA SPEAKING OUT Jason Parrillo, P.E. Chair, FSAWWA
fter attending this year’s strategic planning retreat held on October 3-4 in Ft. Lauderdale, I reminisced on how exciting it was to participate in my first strategic planning event. The year was 2004, and the
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Strategic Planning: The Roadmap to Achieve Section s Future Goals event was held in Tampa. At that time I was not fully aware of how important strategic planning is, nor did I fully grasp the concept of vision and mission statements that guide our core principals. That event was the start of
Participants in the 2013 strategic planning retreat.
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a journey much larger than I could have ever imagined. This year marks the sixth time I have participated in strategic planning for the section: 2004, 2005, 2007, 2010, 2011, and now in 2013. The purpose of having strategic planning retreats is to continually review the section’s vision and mission statements and its goals, make sure they align with where the membership wants the section to be, and determine the best way to get there. The following is the definition of strategic planning from Wikipedia (italics mine): “Strategic planning is an organization’s process of defining its strategy, or direction, and making decisions on allocating its resources to pursue this strategy. In order to determine the future direction of the organization, it is necessary to understand its current position and the possible avenues through which it can pursue particular courses of action. The key components of strategic planning include an understanding of an entity's vision, mission, values, and strategies. Vision: Outlines what the organization wants to be, or how it wants the world in which it operates to be (an ‘idealized’ view of the world). It is a long-term view and concentrates on the future. It can be emotive and is a source of inspiration. Mission: Defines the fundamental purpose of an organization or an enterprise, succinctly describing why it exists and what it does to achieve its vision. Values: Beliefs that are shared among the stakeholders of an organization. Values drive an organization's culture and priorities and provide a framework in which decisions are made. Strategy: Narrowly defined, means ‘the art of the general.’ A combination of the ends (goals) for which the firm is striving and the means (policies) by which it is seeking to get there. A strategy is sometimes called a roadmap, which is the path chosen to plow towards the end vision. The most important part of implementing the strategy is ensuring the company is going in the right direction, defined as towards the end vision.”
The one underlying constant behind strategic planning is this: your goals and priorities will change. In 2007, the section’s goals and priorities completely changed due in part to aligning the strategic plan to its business plan, which is the first time that had ever been done. In 2011, the section’s priorities changed, along with some slight changes to the goals after further review. This year, the section’s goals and priorities have completely shifted again; this time, adopting the AWWA’s newly released strategic plan. You can find the Association’s strategic plan at www.awwa.org/aboutus/strategic-plan.aspx. The members that participated in this year’s strategic planning retreat debated passionately on whether or not we should align the section’s goals and/or how best to align those goals with those of the Association. We also had a lingering debate on the vision for the section. Typically, when debates linger, it is due to semantics; this was no different, and in the end, we agreed to adopt the Association’s mission and vision as our own, with a few slight tweaks of the verbiage. The most interesting part of this development is that the strategic goals were set first, prior to setting the mission and vision; perhaps a bit backwards
in the process, but successful nonetheless. A strategic plan should be a living and breathing document; it should be, by its very nature, dynamic, and it should constantly evolve and adapt to whatever changes need to be made to benefit the membership. The final version of the Florida Section strategic plan will be made availble on the website (www.fsawwa.org) when all revisions have been completed. For those of you who were not able to participate this year, please keep a keen eye on the calendar of events so you don’t miss the next strategic planning retreat. Arguably, there is no better place to witness the implementation of the strategic plan than at the Annual Fall Conference at the various council and committee meetings. It is there that we are able to craft and develop plans of action to benefit our membership. As I mentioned in my January article, perhaps the most valuable privilege you receive as a member of FSAWWA is the ability to bring all the stakeholders together in one room. As Florida’s water professionals, we have a body of talent that is unsurpassed. We have utility personnel, engineers, manufacturers, regulators, contractors, and academicians who provide a breadth and depth of knowledge found nowhere else.
This also provides a value in membership found nowhere else. You can engage in meaningful discussions about issues that directly impact the water industry and come up with creative ways to solve the problem at hand—all without the barriers that office walls typically invoke. Instead, there an open environment in which to collaborate, communicate, and create solutions. As our strategic plan needs to be dynamic, so is our conference, which will be held December 1-5 at the Omni Hotel Resort at ChampionsGate. This year, we are holding an opening general session for the very first time! We have a guest speaker confirmed and I am positive you will find this new addition a welcomed change, energizing you for the workshops, technical sessions, and activities that follow. Immediately after the opening session there will be the grand opening of the exibit hall. This is going to be historic occassion for the Florida Section and one you will remember throughout your career. Don’t miss this once-in-a-lifetime opportunity. Please make sure to visit the section website mentioned previously for more information on the conference. I look forward to seeing you there!
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Certification Boulevard
Roy Pelletier 1. What is one problem associated with aerating water? A. Increase in pH. B. Reduction in hydrogen. C. Reduction in carbon dioxide. D. Possible contamination through the atmosphere.
2. In what units is the presence of suspended and colloidal matter that imparts a cloudy appearance to the water expressed? A. Specific ultraviolet absorbance (SUVA) units B. Threshold odor number (TON) units C. Turbidity units D. Conductivity units
3. Tastes and odors such as grassy, septic, musty, and earthy are all related to what water quality related issue? A. Algae B. Manganese C. Mineral content in the presence of a disinfectant D. Corrosion in metallic pipes
4. What is the health effect associated with water that has excessive color? A. Gastrointestinal distress B. Methemoglobinemia C. Dysentery D. There are no health effects.
Test Your Knowledge of Various Water Treatment Topics 5. When conducting titration with most chemicals, where is the meniscus (level) determined? A. Top of the curve. B. Bottom of the curve. C. Middle of the curve. D. Either the top or bottom; it does not alter test results.
6. What is the maximum filtration rate in a typical pressure filter? A. 2 to 3 gpm/sq ft B. 4 to 5 gpm/ sq ft C. 5 to 10 gpm/ sq ft D. 10 to 100 gpm/sq ft
7. What type of filter media is used to remove tastes and odors? A. Granular activated carbon B. Clay brick C. Garnet D. Alum
8. What condition may occur when unusually low pressures develop in a high-service pump? A. Cavitation B. Backflow C. Backpressure D. Backsiphonage
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/wastewater professional? All past editions of Certification Boulevard through the year 2000 are
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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.
November 2013 • Florida Water Resources Journal
9. How should a sample be preserved when sampling for iron? A. Acidified with nitric acid. B. Cooled to 4°C. C. Add preservative to fix pH above 8.0. D. Iron samples do not require preservatives because it is a metal.
10. What is the purpose of a desiccator in a laboratory? A. Dispensing reagent volumes. B. Calibrating scale weights to known values. C. Remove toxic gases from a flame hood. D. Remove moisture from lab samples.
Answers on page 54
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
Service Name Aquifer Storage and Recovery SERVICE/PRPDUCT DESCRIPTOR
STRATEGIC STORAGE OF RECLAIMED WATER
Headline 30pt. Headline 21pt.
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Reclaimed water stored in an aquifer for beneficial reuse—a success story in Florida. The Destin Water Users’ aquifer storage and recovery (ASR) system has increased the reliability of the water supply, reduced demands on freshwater resources, and helps the utility avoid potential wastewater disposal impacts. With an aquifer similar to many coastal areas, the Destin ASR system provides a prototype for other regions. Read the technical article at
water.slb.com/destin-asr-article © 2201133 SSchlu chlum ch chlu mbe mber berger ger. ge e 13-W 3 WSS-001 3-WS 00018 0018
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Florida Water Resources Journal â&#x20AC;˘ November 2013
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November 2013 â&#x20AC;˘ Florida Water Resources Journal
FWEA FOCUS
The Value of Membership Greg Chomic President, FWEA he Water Environment Federation (WEF) recently announced a dues increase. This column reviews the cost and benefits of membership and the details of this increase. First, let’s review the benefits. As you probably know, when you receive your membership renewal notice each year, the base membership fee includes membership in both WEF and the Florida Water Environment Association (FWEA). In a sense, WEF is our mother ship—an international federation of water quality member associations (MAs) that includes 51 MAs in North America and more than 20 international MAs. The Federation provides FWEA with a substantial amount of support, including WEF member association and individual awards, WEF board participation at our annual conference and meetings, membership dues billing and collection, WEF member association exchange meetings (WEFMAX), leadership training, and public education programs and materials. The FWEA is represented on the WEF House of Delegates by two delegates; more on that later. In addition, WEF also offers each of us as individual members several benefits: technical periodicals, like Water Environment & Technology; discounts on WEFTEC, WEF specialty conferences, manuals of practice (MOPs), and other reference books; no-charge webcasts; and public policy representation and support for the wastewater industry at the federal level. And, if you haven’t done so recently, I recommend you visit the WEF website (www.wef.org); it contains a wealth of educational and volunteer support material. The FWEA members, and all of us as individual WEF members, receive these benefits when we pay our annual membership fee. These fees are among the lowest in the water quality industry and haven’t changed significantly over the past 10 years. Currently, a professional and academic member pays $131 per year for the combined WEF and FWEA membership; $88 of that goes to WEF and $43 goes to FWEA. A professional wastewater operator pays $80 for the combined membership, with $47 going to WEF and $33 going to FWEA.
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Those of us who belong to other professional associations know that these rates are very competitive. The WEF staff recently concluded an indepth examination of WEF’s pricing and member support cost structure and determined that it costs $159.69 per year to serve a member. Given the pricing structure outlined, it became readily apparent that maintaining (never mind improving) the current level of service would not be sustainable without adjustments. These adjustments will take the form of three annual dues increases in 2014, 2015, and 2016. In 2014, the WEF/FWEA combined professional membership dues will increase by $13 to $144, and the professional wastewater operator dues will increase by $7 to $87. The 2014 dues increase will show up on our renewal notices for the coming year. The Federation has not yet announced what the increases will be in 2015 and 2106. As a fellow WEF member, even with these proposed increases, I still consider WEF membership to be a good investment. I have no hesitation to pay the dues increase and I appreciate what WEF has done to keep our dues down for so long. I hope you come to the same conclusion; however, if you have any concerns or questions, please do not hesitate to contact me at 407-948-0332 or gchomic@heywardfl.com. With all of that said, I am pleased to report that the FWEA board has decided not to increase FWEA’s portion of the WEF/FWEA annual membership fee. Although the Florida municipal wastewater industry is starting to show some signs of renewed economic vitality, we don’t feel that a state dues increase is appropriate at this time. As an almost all-volunteer association, we have become accustomed to watching every penny spent, while providing low-cost training and networking opportunities to the membership. And as mentioned in my July column, FWEA now offers an FWEA-only membership to government employees. The $50 FWEAonly annual membership fee qualifies members to receive all the benefits of FWEA membership, including the Florida Water Resources Journal, the Florida Watershed Journal, and The Droplet, as well as discounted registration fees for all FWEA conferences, seminars, and local chapter networking events. Our goal is to help water quality professionals employed by municipal and state government,
who may not receive employee-sponsored membership benefits, enjoy the benefits of FWEA membership. If you are interested in, and qualify for, this membership category, please go to the FWEA website (www.fwea.org), click on the “Membership” tab on the home page, and then click on the “FWEA-only Membership” tab from the drop down menu.
Announcing Our New WEF Delegate I am pleased to announce that FWEA past-president Paul Pinault of CDM Smith has accepted the WEF delegate position being vacated by Pam Holcomb of CH2M Hill. We appreciate Pam’s many years of dedicated service to the members of WEF and FWEA. We look forward to Paul’s contributions to WEF, and his continued support for FWEA, as his brings his vast experience and industry relationships to the national stage. Paul started his term at the WEF House of Delegates meeting on October 5 at WEFTEC and will serve for two years. Paul will serve with WEF delegate John Giachino of The Haskell Company and FWEA Executive Director Pat Karney, who was recently elected as a delegate-at-large to the WEF House of Delegates. Florida continues to be well represented within the governing structure of WEF, to the benefit of both the Federation and FWEA.
become
A MEM
BER
Florida Water Resources Journal • November 2013
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JANUARY 2014 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
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 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 *** any retest given also
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November 2013 â&#x20AC;˘ Florida Water Resources Journal
You are required to have your own calculator at state short schools and most other courses.
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
Water Treatment . Look above each set of questions to see if it is for water operators (DW), distribution system or wastewater operators (DS), 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.
___________________________________________
New Path to Permitting Aquifer Storage and Recovery Systems in Florida Jennifer Stokke Nyfennegger, Chance Lauderdale, Jess Brown, and Kara Scheitlin (Article 1: CEU = 0.1 DW/DS)
1. The _________ strategy is often set to achieve a balance between biological activity and hydraulic performance. a. disinfection b. backwash c. nutrient balance d. flow control 2. Low doses of ____________ effectively oxidize and remove extracellular polymeric substances. a. hydrogen peroxide b. carbon c. nitrogen d. phosphorus 3. Without ____________ at the Tampa Bay and Dallas sites, nutrient supplementation did not improve biofilter performance. a. increased backwash frequency b. ammonia nitrogen enhancement c. frequent chlorination d. pH adjustment 4. Of those tested, which biofilter media type was demonstrated to be superior under all test conditions? a. Sand b. Granular activated carbon c. Anthracite d. Fixed film 5. The study discussed in this article demonstrated that a. pH is not relevant to biofilter optimization. b. chlorine dioxide is the most effective agent for removing spent biomass. c. biofilters can decrease coagulant requirements by > 50 percent. d. a light dose of powdered activated carbon can extend biofilter life.
(Credit Card Number)
(Expiration Date)
Comparing Aluminum and Iron Coagulants to Remove Organic Carbon, Color, and Turbidity From a Florida Slough David T. Yonge and Steven J. Duranceau (Article 2: CEU = 0.1 DW/DS}
1. ____________ is/are identified by the authors as a surrogate for disinfection byproduct precursors. a. Total dissolved solids b. Synthetic organic compounds c. Turbidity d. Natural organic matter 2. The true color value of Florida surface water is as high as ________ platinum-cobalt units (PCU). a. 15 b. 50 c. 100 d. 700 3. Jar testing discussed in this article was performance in accordance with _____ standards. a. American Water Works Association (AWWA) b. Underwriters Laboratories (UL) c. Standard Methods for the Examination of Water and Wastewater d. American Society for Testing and Materials (ASTM) 4. Which of the following tested coagulants was not observed to add turbidity to the water? a. Aluminum chlorohydrate (ACH) b. Alum c. Ferric chloride d. Ferric sulfate 5. _________ is a semivolatile disinfection byproduct that can be removed by stripping under certain conditions. a. Bromodichloromethane b. Chloroform c. Haloacetic acid d. Ozonated hydrocarbon Florida Water Resources Journal • November 2013
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F W R J
Bench-Scale Evaluation of Chlorine-Ammonia Process for Bromate Control During Ozonation Hongxia Lei, Dustin W. Bales, and Jon S. Docs he David L. Tippin Water Treatment Facility (Facility), located in Tampa, is an advanced ozonation water treatment plant with a capacity of up to 120 mil gal per day (mgd), consisting of coagulation, flocculation, sedimentation, ozonation, and biofiltration. Its source water comes from the Hillsborough River. During the wet season (June-September), excess water is treated and pumped into a series of aquifer storage and recovery (ASR) wells. The ASR water is then pumped back out during the dry season (October-May) to supplement water supply. The high dissolved oxygen content of finished water pumped into the ASR wells frees bromide from the geological formation. The increased bromide from the ASR wells increases the total bromide in the water to a level where bromate formation during ozonation nears or exceeds the U.S. Environmental Protection Agency (EPA) maximum contaminant level (MCL) of 10µg/L on an annual average. Currently, pH is used as the primary control strategy. A decrease in pH inhibits bromate formation; however, pH depression prior to ozonation is operationally challenging and also costly at the Facility. A bench-scale study of an alternative bromate control strategy, i.e., the chlorine-ammonia process, was performed to evaluate the efficacy of the process to reduce bromate formation. The study was conducted simulating full-scale conditions using Hillsborough River water. The chlorine-ammonia process involves first adding chlorine, and, after a 5-min delay, ammonia is added, quickly followed by ozonation. The process forms hypobromite from hypochlorite, which then reacts with the added ammonia to form bromamines. Bromate formation is hence effectively minimized as hypobromite is consumed and becomes less available for bromate formation during the ozonation process. The bromamines created can react with organics present in the water in a similar way to chloramines, providing a negligible amount of disinfection prior to conversion back to bromide. This bromate control strategy allows water treated by ozone at a
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higher pH, or with a longer ozone contact time if needed, for meeting Cryptosporidium inactivation requirements and assisting taste and odor reduction.
Background Potassium bromate (KBrO3) was identified as a possible carcinogen in the early 1980s. It was first reported that oral administration of potassium bromate led to renal cell tumors in rats (Kurokawa et al., 1982) and further research showed that it was a probable carcinogen to humans (Kurokawa, 1990). As a result of this research, the U.S. Environmental Protection Agency (EPA) added bromate to a list of contaminants for consideration of regulation in 1994. In 1998, EPA’s Stage 1 Disinfection and Disinfection Byproducts Rule went into effect under the Safe Drinking Water Act, placing byproducts such as trihalomethanes and haloacetic acids under more stringent regulation (EPA, 1998). Bromate is a disinfection byproduct (DBP) associated with ozonation. Ozone as a disinfection method is becoming more popular in the United States to meet higher disinfection requirements, as well as increase taste and odor control, going from 40 ozone installations in 1991 to close to 280 in 2012 (Leob et al., 2013; EPA, 1999). The increasing market penetration of ozone combined with the new EPA regulations made bromate minimization increasingly important. The bromate formation mechanism during ozonation is well studied and primarily consists of three pathways. The first is a direct pathway involving molecular ozone; the second is a direct-indirect pathway involving first molecular ozone and then hydroxyl radicals from ozone decomposition; and the third is an indirect-direct pathway where the hydroxyl radicals react first, then the molecular ozone (Song et al., 1997; von Gunten and Hoigné, 1994; Haag and Hoigné, 1983). Von Gunten and Oliveras (1998) incorporated additional reactions and successfully confirmed the model based on laboratory experiments and
November 2013 • Florida Water Resources Journal
Hongxia Lei is the water quality assurance officer and Jon S. Docs is senior environmental scientist with City of Tampa Water Department. During this project, Dustin W. Bales was a graduate student at the University of South Florida and an intern with City of Tampa.
kinetic modeling. Based on bromate formation mechanism, a novel approach using a chlorine-ammonia process was developed using a bench-scale ozonation system and its efficiency evaluated at varying pH, ozone exposure, and chlorine concentrations (Buffle et al., 2004). Wert et al. (2007) confirmed the efficacy of the chlorine-ammonia process for bromate reduction in a pilot-scale ozonation system using Colorado River water and validated the pilot results with full-scale implementation. The water from the Hillsborough River is dramatically different from the Colorado River. During the wet season, total organic carbon (TOC) could spike up to 45 mg/L due to the large amount of organic matter flushed out of the swamp and tributaries by heavy rains into the river. Color and other water quality characteristics vary seasonally as well, which poses a unique challenge in treating the Hillsborough River water. The purpose of this study was to evaluate the chlorine-ammonia approach for bromate control using the Hillsborough River water, and determine the optimal doses and the associated financial benefit. As illustrated in Figure 1 of the general treatment process at the Facility, pH is controlled at 4.5 for enhanced coagulation. After coagulation/flocculation, pH is raised to 6.5 by adding lime or Ca(OH)2 (calcium hydroxide) before the bromide-containing water is treated by ozone. After ozonation, lime can no longer be used for pH adjustment as it will cause a turbidity issue. As a result, caustic soda or sodium hydroxide (NaOH) has to be added at two locations downstream of the ozone to further increase pH to around 7.8
before the water is sent to customers. This pH control strategy is costly as only limited amounts of lime can be used. Lime has a fourfold advantage over caustic soda as it costs half as much, and its bivalent nature makes it twice as effective. For this reason, the chlorine-ammonia process was investigated, as this will allow ozone to occur at higher pH without violating bromate MCL, which will result in more lime usage and less caustic soda consumption.
Materials and Methods Reagents The Indigo Stock Solution consisted of 0.770 g of ACS-grade potassium indigo trisulfonate and 1 millilitre (mL) of 85 percent high-performance liquid chromatography (HLPC)-grade concentrated phosphoric acid per 1 liter of solution. The stock was stored in an amber bottle for less than four months. The Indigo Reagent Solution consisted of 50 mL of the Indigo Stock Solution, 11.5 g of sodium phosphate monobasic monohydrate, and 7.0 mL of HPLC-grade concentrated phosphoric acid. It was stored in an amber bottle for less than one week. The 100-mg/L bromide stock was created by diluting 1000 parts per mil (ppm) bromide stock solution. The 400 ppm ammonia stock contained 1529 milligrams (mg) of ammonium chloride per liter of solution. Chlorine stock had a target concentration of 600 ppm, and was made by adding 11 mL of 5-6 percent hypochlorite stock solution to 1 liter of water. Chlorine stock solution concentration was tested weekly to determine if the concentration remained steady. All solutions were prepared with distilled deionized water (DDI water). Ozone stock solution was created by dissolving a mixture of ozone and oxygen gas generated by an ozone generator operated at 50 percent capacity and 1 liter per min oxygen flow rate into DDI water using a coarse gas wash bottle. Off-gas was treated with a sodium thiosulfate solution for quenching. The gas wash bottle was placed in an ice bath prior to generation. The generator was run for 30 min to achieve a steady state solution. Experimental Methods A 100-ml gastight syringe was used as the reactor vessel in all experiments. The syringe was placed inside of a water bath, which was maintained at 20ÂşC. The syringe was connected to the outside of the water bath using 1/16-in. diameter 316 stainless steel tubing with a control valve for sampling and chemical dosing (Figure 2).
Figure 1. Current Treatment Process at the Facility.
Figure 2. Experimental Setup for the Bench-Scale Ozonation Apparatus.
Prior to each experiment, the pH of the test water was adjusted to pH 7 using hydrochloric acid or sodium hydroxide, followed by a bromide spike. Afterwards, the sample was placed in the reactor with the plunger removed. The syringe was filled to the top, and the plunger was then pushed in to ensure no air was in the syringe. A stir bar placed inside the reactor was stirred by a waterproof stir plate inside the water bath. The volume inside the reactor was adjusted to 85 mL. Some of the sample was retained in a 5-ml syringe for final volume adjustment. After approximately 10 min (allowing temperature to adjust from room temperature), chlorine was added in the appropriate dose using a 500-Âľl gastight syringe.
Approximately 1 mL of the retained sample in the second syringe was used to flush the chlorine from the tubing into the reactor. After 5 min, the ammonia was added in the appropriate dose and flushed into the reactor using the same syringes and process. One min after the ammonia dosing, 7-8 mL of ozone stock solution was added to the reactor. The stock was then flushed out of the tubing and the volume adjusted to exactly 100 mL using the 5ml syringe. The 5-ml gastight syringes were used to pull ozone samples from the reactor. They were prefilled with 3 mL of indigo reagent solution. Samples were taken every min for the first 10 min, and less frequently after 10 min until the ozone concentration was 0.1 mg/L or below. Continued on page30
Florida Water Resources Journal â&#x20AC;˘ November 2013
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Continued from page 29 Analytical Methods Dissolved ozone was measured with a spectrophotometer using a method similar to the Standard Method 4500-Ozone (Chiou et al., 1995; Bader and Hoigne, 1981) in order to be able to follow the rapid ozone decay. Bromate analysis was performed on an ion chromatography system using EPA Method 300C. The CT values (ozone concentration × contact time) were obtained by integrating the ozone decay curve generated in each experiment.
Experimental Design Table 1 shows the labeling identification used for each condition and the associated pH, bromide concentration, chlorine concentration, and ammonia concentration. Three different chlorine concentrations were used with ammonia varying for each chlorine concentration. A pH value of 7.0 was selected as an improvement of the pH of 6.5 currently implemented at the full-scale plant in order to lower the cost of caustic soda, in addition to the benefit of better bromate control. The testing
Table 1. Experimental Matrix Used for Bromide Concentrations of 273 µg/L and pH 7.
water was collected before ozonation from the full-scale plant. The water was analyzed for TOC (4.1 mg/L), bromide (73 µg/L), bromate (non-detect), calcium hardness (124 mg/L), ammonia (0.1 mg/L NH3-N), UV-254 (0.06), and alkalinity (48 mg/L as CaCO3). Baseline conditions at pH 7.0 without any chlorine or ammonia addition and bromide spiked at 0, 100, 150, 200, and 250 µg/L and were studied first to establish the initial bromate formation without any optimization. Since the background bromide was 73 µg/L, the actual bromide concentrations were adjusted accordingly, as reflected in Table 1. The rest of the matrix varied ammonia for three distinct groups of chlorine concentrations using ratios similar to Wert et al. (2007) with bromide fixed at 273 µg/L, a number representative of the full-scale conditions during the dry season. Similarly, the initial ozone dose was selected to achieve a target CT in the range of 4 to 7 min·mg/L, typically encountered at the full-scale system.
Results and Discussion
Figure 3. Full-Scale Ozone Demand, Bromide, and Bromate at the Facility: 2009-2011.
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November 2013 • Florida Water Resources Journal
The general relationship among bromate, bromide, and ozone demand is presented in Figure 3 based on three years of full-scale data from the Facility. The fullscale ozone contactor has internal baffles that separate the contactor into eight cells, with water going in from cell No. 1 and leaving from cell No. 8. Ozone demand is the difference between the ozone dosed and the ozone concentration in cell 5, which is typically close to non-detect. Clearly, bromate increases with either bromide concentrations or ozone demand. Ozone demand increases during high TOC and high color events (data not shown). While pH has a large effect on bromate production, it is not included in the graph because it is fixed to a tightly controlled range (6.2-6.5) to prevent bromate formation at the full-scale plant, making it difficult to see any relationship between pH and bromate formation. Before the water is treated by ozone, TOC ranges from 1-5 mg/L, cycling seasonally, with the highest range occurring during the rainy summer season and lowest during the drier winter. Flow rate also exhibits a seasonal trend, ranging from a dry season low of around 60 mgd to a wet season high of 100 mgd. Bromide conversion to bromate averages 1.8 percent during the dry season and 3 percent during the wet season. Bromate formation in all conditions must be compared with the same CT in order to identify the best chlorine and ammonia dosContinued on page 32
Florida Water Resources Journal â&#x20AC;˘ November 2013
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Figure 4. Example of Adjusted Bromate Calculation.
Table 2. Bromate Formation Under Various CT Values in Bench-Scale Experiments.
Figure 5. Bromate Formation at Varying NH3 :Cl2 Ratios.
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November 2013 • Florida Water Resources Journal
Continued from page 30 ing for bromate control. However, the actual CT achieved in the bench-scale experiments could be different depending on the ozone decay kinetics and initial ozone stock solution. To compare results between replications, bromate values had to be normalized using CT with linear regressions. An example of this process is illustrated in Figure 4. A CT inside the range of CTs for each replicate was used to predict the bromate at a target CT that can easily be compared to other sets. All the normalized bromate formation is presented in Table 2 as “CT-adjusted bromate” with its associated CT used for interpolation. Note that only interpolation was used, but not the extrapolation, because the relationship between CT and bromate formation is nonlinear, and thus extrapolation is inaccurate. As a result, only interpolation was used and limited by the CT range achieved under each condition and bromate numbers could not be always adjusted to the same CT. After adjusting each data set to a target CT within the range, a CT-adjusted bromate value can be calculated; all the variations of the experiment can then be compared, to a certain extent. The groups at 0.25 mg/L and 0.5 mg/L Cl2 all had CTs within a certain range, and were able to be adjusted to 5.3 min·mg/L and 6.2 min·mg/L, respectively. The data for 0.75 mg/L Cl2 did not have consistent enough CTs to allow for this, so a CT for each condition had to be used. A higher CT leads to a higher bromate concentration. Because of this, set ID # 7-0.45-0.75-200 in Table 2 is likely a significantly better control measure compared to set ID# 7-0.3-0.75-200 due the nearly identical bromate value, but has a significantly higher CT value. The least effective ammonia-chlorine dosing regimen (ID# 7-0.1-.25-200) resulted in an over 50 percent reduction in bromate formation. The most effective (the last three in Table 2) resulted in an 86 percent reduction in bromate formation. At typical plant conditions, this represents a near-zero risk of ever exceeding the MCL for bromate. Overall, having ammonia in excess causes an improvement in bromate prevention throughout all conditions, except when chlorine was dosed at 0.75 mg/L where no additional benefit was observed with 0.6 mg/L ammonia. The best bromate formation reduction was achieved when chlorine was dosed at 0.75 mg/L and ammonia at 0.45 mg/L (Figure 5). The optimal chlorine and ammonia doses for bromate control presented is somewhat different from the results presented by Wert et al. (2007), apparently due to the difference in water quality parameters between the Col-
orado River in Nevada and Hillsborough River in Florida. The Wert study utilized Lake Mead water with the following characteristics: alkalinity (137 mg/L), total hardness (288 mg/L CaCO3), TOC (2.59 mg/L), and pH (7.95). The optimal ratio found in that study was 0.5 mg/L NH3 to 0.5 mg/L Cl2, which was the highest concentration of both used in the study. This ratio produced less than 1 µg/L bromate at a CT of 4.41 min·mg/L. For comparison, the best ratio in this study is 0.45 mg/L NH3 to 0.75 mg/L Cl2, which produced 1.09 µg/L bromate at a CT of 6.8 min·mg/L. The results in this study demonstrated again the impact of source water and the necessity of running bench- or pilot-scale studies before full-scale implementation. However, results in Figure 5 do suggest that any of the chlorine and ammonia combinations investigated in this study would work well with at least 50 percent bromate reduction. To determine the cost/benefit of switching to an increased ozonation pH, the buffer capacity of the water was determined by experiments (Figure 6), which was almost identical to the theoretical buffer curve. Currently, lime is used to increase the water’s pH from 4.5 to 6.5 and caustic soda from 6.5 to 7.5. With the chlorine-ammonia bromate control approach, lime can be used to increase pH to 7.0 and caustic soda from 7.0 to 7.5. As a result of this alternative practice, based on Figure 6, lime usage would increase by about 21 percent of the total required pH increase, and caustic would decrease by 11 percent. Because the Facility typically has no bromate concerns outside of the months of January-May, the decision was made to increase the ozonation pH prior to completion of the fullscale plant’s ammonia and chlorine preozonation dosing facilities, which will be completed in early 2014, when bromate will again be an issue. On May 22, 2012, the pH of ozonation was increased to 7.0; the change immediately resulted in cost savings in the following months. To determine the benefit of the change, costs for lime and caustic soda from the previous year were compared to the current year. Because of the bivalent nature of lime, combined with its significantly lower cost over caustic soda, the treatment plant has saved $495,500 in a four-month period compared to the same period of 2010 and 2011. The month-by-month costs can be seen in Figure 7. Once the capital improvement project is complete, allowing chlorine-ammonia approach to control bromate and ozonation occurring at pH 7.0 year round, the estimated annual chemical savings will be over $1 million. Continued on page 34 Florida Water Resources Journal • November 2013
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Continued from page 33
Conclusions Bromate control using the chlorine-ammonia process is very effective, resulting in a 50 percent reduction in bromate over the control group in the worst case and an 86 percent reduction in the best case. A ratio of around 1:2 NH3 :Cl2 with ammonia concentration of 0.45 mg/L appears to be the most effective. While the ideal ratio between chlorine and ammonia does vary and could be different for untested water quality matrices, this study has shown this approach is very tolerant. Under any of the studied conditions, bromate was reduced by at
least 50 percent. This implies that if a utility doesn’t have the resources to perform its own bench- or pilot-scale tests, this ratio could be directly applied and further optimized at the full-scale plant due to the efficacy of the process.
References • Bader, H.; Hoigné, J., Determination of ozone in water by the indigo method. Water Research 1981, 15, 449-456. • Buffle, M.-O.; Galli, S.; von Gunten, U., Enhanced bromate control during ozonation: the chlorine-ammonia process. Environmental Science & Technology 2004, 38 (19), 5187-5195.
Figure 6. Buffer Capacity Curve Showing Percentages of pH Change by Lime and Caustic Soda.
Figure 7. Combined Monthly Caustic Soda and Lime Costs at the Facility: 2010-2012.
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November 2013 • Florida Water Resources Journal
• Chiou, C. F.; Mariñas, B. J.; Adams,, J. Q., Modifed indigo method for gaseios and aqueous ozone analysis. Ozone Science and Engineering 1995, 17(3), 329-344. • Environmental Protection Agency, EPA Guidance Manual: Alternative Disinfectants and Oxidants. 1999, http://water.epa.gov/lawsregs/ rulesregs/sdwa/mdbp/upload/ 2001_01_12_ mdbp_alter_ chapt_3.pdf. • Environmental Protection Agency, National primary drinking water regulations: disinfectants and disinfection byproducts. Federal Register 1998, 63 (241), 69390-69476 • Haag, W. R.; Hoigne, J., Ozonation of bromide-containing waters: kinetics of formation of hypobromous acid and bromate. Environmental Science & Technology 1983, 17 (5), 261-267. • Song, R.; Westerhoff, P.; Minear, R.; Amy, G., Bromate minimization during ozonation. Journal American Water Works Association 1997, 89(6), 69–78. • Kurokawa, Y.; Hayashi, Y.; Maekawa, A.; Takahashi, M.; Kokubo, T., Induction of renal cell tumors in F-344 rats by oral administration of potassium bromate, a food additive. Gann 1982, 73 (2), 335-338. • Kurokawa, Y.; Maekawa, A.; Takahashi, M.; Hayashi, Y., Toxicity and carcinogenicity of potassium bromate--a new renal carcinogen. Environmental health perspectives 1990, 87, 309-35. • Loeb, B. L.; Thompson, C. M.; Drago, J.; Takahara, H.; Baig, S., Worldwide ozone capacity for treatment of drinking water and wastewater: a review. Ozone: Science & Engineering 2012, 34(1): 64-77. • von Gunten, U.; Hoigne, J., Bromate formation during ozonization of bromide-containing waters: interaction of ozone and hydroxyl radical reactions. Environmental Science & Technology 1994, 28 (7), 12341242. • von Gunten, U.; Oliveras, Y., Advanced Oxidation of Bromide-Containing Waters: Bromate formation mechanisms. Environmental Science & Technology 1998, 32 (1), 63-70. • Wert, E. C.; Neemann, J. J.; Johnson, D.; Rexing, D.; Zegers, R., Pilot-scale and full-scale evaluation of the chlorine-ammonia process for bromate control during ozonation. Ozone: Science & Engineering 2007, 29 (5), 363-372.
Florida Water & Pollution Control Operators Association
FWPCOA STATE SHORT SCHOOL March 24 - 28, 2014 Indian River State College - Main Campus – FORT PIERCE –
COURSES Backflow Prevention Assembly Tester ..........................$375/$405
Utility Customer Relations I, II & III................................$260/$290
Backflow Prevention Assembly Repairer ......................$275/$305
Utilities Maintenance ....................................................$225/$255
Backflow Tester Recertification ......................................$85/$115
Wastewater Collection System Operator C, B & A ......$225/$255
Basic Electrical and Instrumentation ............................$225/$255
Water Distribution System Operator Level 3, 2 & 1 ......$225/$255
Facility Management Module I......................................$275/$305
Wastewater Process Control ........................................$225/$255
Reclaimed Water Distribution C, B & A ........................$225/$255 (Abbreviated Course) ................................................$125/$155
Wastewater Sampling for Industrial Pretreatment & Operators................................................................$160/$190
Stormwater Management C & B ...................................$260/$290
Wastewater Troubleshooting ........................................$225/$255
Stormwater Management A .........................................$275/$305
Water Troubleshooting ..................................................$225/$255
For further information on the school, including course registration forms and hotels, download the school announcement at www.fwpcoa.org/fwpcoaFiles/upload/2014SpringSchool.pdf
SCHEDULE CHECK-IN: March 23, 2014 1:00 p.m. to 3:00 p.m. CLASSES: Monday – Thursday........8:00 a.m. to 4:30 p.m. Friday........8:00 a.m. to noon
FREE BBQ DINNER + Monday, March 24, 4:30 p.m. + 3209 Virginia Ave Fort Pierce, FL 34981
For more information call the
FWPCOA Training Office 321-383-9690 Florida Water Resources Journal • November 2013
35
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
Spotlight: Central Florida Chapter ership excellence at the University of Central Florida (UCF) to Mason Gardberg, who is in its college of engineering and computer science. Congratulations Mason!
VICKERS
HENDERSON
FRIES
Kevin Vickers, Devan Henderson, and Kristi Fries he Central Florida Chapter of FWEA has been busy in 2013. The chapter has hosted and participated in activities ranging from outreach and volunteer events to technical luncheons. The chapter continues to be involved in the community, and maintains partnerships with other organizations in planning select events. The following is a list of the most recent activities attended by chapter participants.
T
Technical Luncheon: Securing Critical Control Systems in the Water Industry A technical luncheon was held on May 16 at the Dubsdread Tap Room near downtown Orlando. The main topic covered was titled, “Securing Critical Control Systems in the Water Industry.” There was discussion on the growing need for cyber security, protecting critical infrastructure. and security recommendations. A special thanks to the presenters, Michael Sutton, P.E., and Tom VanNorman, CISSP. In addition to the lunch program, FWEA presented a scholarship for academic and lead-
6th Annual ASCE/FWEA Icebreaker The FWEA partnered with the American Society of Civil Engineers (ASCE) to hold a joint icebreaker event on July 18 at the Orlando Science Center. There were 193 attendees representing 13 organizations: Florida Water Environment Association (FWEA) American Public Works Association (APWA) Florida Engineering Society (FES) Society of Women Engineers (SWE) Central Florida Association of Environmental Professionals (CFAEP) Metropolitan Environmental Training Alliance (METRA) FWEA Central Florida Chapter (CFC) Florida Surveying and Mapping (FSMS) Florida Floodplain Managers Association (FFMA) ASCE Education Committee ASCE Young Members Forum (YMF) Water for People UCF Steel Bridge Team Also in attendance were members from three public entities: UCF Alumni/Engineering Department, City of Orlando, and Orange County. Attendees were able to enjoy a fun night of networking as well as learn about local organizations. Thank you to all of the sponsors who helped to make this year’s icebreaker a success.
Oyster Mat Party An Oyster Mat Party was held on August 6 at the AECOM office in Orlando. This event was in partnership with the Coastal Conservation Association (CCA) and The Nature Conservancy (TNC). Attendees helped assemble oyster shell mats that will be used to help restore local oyster reefs. The event was a big success! There were 47 attendees, and all together they assembled 60 oyster mats. Participants were also given the opportunity to name a reef. A special reef in the Mosquito Lagoon will now bear the name “FWEA-ASCE.”
Participants working on oyster mats.
Pictured are Kunal Nayee, Daniel Mangrove, Derek Bieber, Chuck Olsen, Kirk Fusco, Angel Martin, Deborah Cole, and Jackie Martin.
FWEA/FSAWWA Annual Wastewater Utilities Panel
Presenter Michael Sutton
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Pictured are Nicole Kolankowsky, Angel Martin, Scott Richards, Deborah Cole.
November 2013 • Florida Water Resources Journal
The Annual Wastewater Utilities Panel was held on August 23 at the Dubsdread Tap Room. This wastewater panel discussion featured representatives from five different utilities in the central Florida area, consisting of Vic Godlewski, P.E., with City of Orlando; Andrew Neff, P.E., with Seminole County; Jason Her-
rick, P.E., with Orange County Utilities; Robert Pelham, P.E., with Toho Water Authority; and Ted McKim, P.E., with Reedy Creek Energy Services. Bob Morrell, P.E., with Orange County Utilities, served as panel moderator and facilitated the discussions. The luncheon had a good turnout of 125 attendees. A special thank you to our lunch sponsors: Barney’s Pumps Inc., Tetra Tech, and Environmental MD Inc.
14th Annual Scholarship Golf Tournament
The chapter would like to gratefully thank all of the sponsors and participants involved in the event. The platinum sponsors were: Atkins, Black and Veatch, Carollo Engineers, CPH Inc., Environmental-MD, Heyward Florida Incorporated, Jones Edmunds, MaxWest Environmental Systems, and Tetra Tech. The silver sponsors were: Arcadis, BFA Environmental Consultants, CH2M Hill, and EnviroSales of Florida. The bronze sponsors were: Hydra Service Inc. and Schneider Electric. Thank you to the volunteers who made this event possible. The members of the Central
Florida Chapter Golf Tournament Committee were Kristi Fries, chair of the Golf Tournament Committee; Nicole Kolankowsky, chair of the FWEA Central Florida Chapter; and Kenny Blanton, Angel Martin, Alyssa Filippi, Jackie Martin, Stacey Smich, Deborah Cole, and Jay Morris. Kevin M. Vickers, E.I., is project engineer with Kimley-Horn and Associates Inc. Devan Henderson, P.E., is project engineer with Reiss Engineering Inc. Kristi Fries, P.E., is project manager in the capital improvement and infrastructure division at City of Orlando Public Works Department.
The chapter held its 14th Annual Scholarship Golf Tournament on September 20 at Falcon’s Fire Golf Club. The proceeds from the golf tournament benefit the “Gabe Delneky Scholarship Fund” and the “Norm Casey Scholarship Fund” for local students who are pursuing engineering degrees at the UCF. The tournament is funded by donations from sponsors and competitors playing in the tournament. The event was highly successful, with 104 golfers participating and over $3,500 raised for the scholarship fund. It was a fierce competition throughout the day, but the first-place team was from URS Corporation and included (from left to right) Tim Todd, Kevin Goolsby, David Wilcox, and Craig Fuller.
The MTS Environmental team, consisting of (from left to right) Mark Hickinbotham, Ben Fries, Bob Bierhorst, and Bob Solomon, secured second place.
The individual contest winners included Andy Meiers, from the MaxWest Environmental Systems team, for Men’s Longest Drive, and Kim Krutski, from the Atkins team, for Women’s Longest Drive. Greg Taylor, from the CDM Smith team, received the Closest-to-thePin Award, and Cameron Young, from the Moss Kelley team, took home a cash prize for being the Putting Contest Winner. Florida Water Resources Journal • November 2013
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F W R J
Dynamic Operation of Ultrafiltration Membranes for Potable Water Production Christopher C. Boyd and Steven J. Duranceau n March 2010, the University of Central Florida (UCF) began a two-year ultrafiltration (UF) pilot test at the Lake Manatee Water Treatment Plant (WTP) in Manatee County. In September of that same year, a second UF pilot study commenced at the Mission San Jose WTP in Fremont, Calif. The Lake Manatee and Mission San Jose WTPs were identified as excellent pilot test locations, because the facilities treated two distinctly different surface water sources. The Lake Manatee WTP treats water from the Lake Manatee Reservoir with alum coagulation, flocculation, sedimentation, and periodic powdered activated carbon (PAC) dosing for seasonal taste and odor events. In contrast, the Mission San Jose WTP practices ferric chloride coagulation with upflow solids contact clarifiers to treat water from the Sacramento delta. Fouling management is a critical component of UF operation for surface water treatment, and coagulation, along with other processes such as preoxidation and adsorption, are useful pretreatment options for UF membranes (Howe & Clark, 2006; Huang et al., 2009; Campinas & Rosa, 2010; Gao et al., 2011). While pretreatment improves feed water quality to UF processes, the selection of process parameters is also important for fouling management. A strong correlation exists between flux and membrane fouling (Field et al., 1995; Howell, 1995; Wu et al., 1999; Bacchin et al., 2006), and the selection of items such as the backwash frequency and duration are also significant (Kim & DiGiano, 2006; Smith et al., 2006). Regardless of the pretreatment and operating strategies, fouling inevitably develops at the membrane surface. Accordingly, it is important to identify viable cleaning chemicals and chemical maintenance protocols for the water being treated (Yuan & Zydney, 2000; Katsoufidou et al., 2008; Strugholtz et al., 2005; Zondervan & Roffel, 2007; Porcelli & Judd, 2010; Liu et al., 2006). Surface water variability (Ouyang et al., 2006; Boyd & Duranceau, 2012) and the dynamic operation of pretreatment processes result in a continuously changing feed water quality to UF membranes. Accordingly, performance improvements may be made possible by varying UF operating protocols in response to changing inputs. This article presents the re-
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sults of a study designed to assess the impact of dynamic UF process operation on membrane fouling and productivity. Tools for analyzing process data during dynamic operation are presented, along with additional recommendations for implementing dynamic operating protocols.
Description of Ultrafiltration Pilot Units The Lake Manatee and Mission San Jose UF pilots were each equipped with a single Durasep UPF0860 (Toyobo CO. Inc) hollow-fiber UF membrane operated in an inside-out direct filtration mode. Durasep UPF0860 membrane fibers are manufactured from hydrophilic polyethersulfone (PES) blended with polyvinylpyrrolidone and provide 150,000 dalton cutoff and 430 ft2 of surface area. The pilot units operated at a constant flux and recorded process data at regular intervals using onboard pressure sensors, feed and filtrate turbidity meters, and flow meters. Filtrate was collected in storage tanks for use during backwashes and chemically enhanced backwashes (CEBs). A programmable logic controller (PLC) was employed to automate the pilot units and two onboard chemical injection systems enabled routine CEBs.
Process Data Analysis Process Performance Assessment In this article, the filtration, backwash, and CEB functions of an ultrafiltration process are termed “process events.” These process events are further organized into sequences and cycles, where a sequence consists of a consecutive filtration and backwash event, and a cycle contains a number of sequences culminating in a CEB. Collectively, successive sequences and cycles determine the performance of UF processes by influencing membrane fouling. UF process performance may be assessed by temperature correcting the transmembrane pressure, or TMP (U.S. Environmental Protection Agency, 2005). The temperature-corrected TMP (TCTMP) adjusts for the effects of water temperature on operating pressure. Membrane-specific temperature correction factors (TCFs) may also be used (Duranceau & Taylor, 2011).
November 2013 • Florida Water Resources Journal
Christopher C. Boyd, Ph.D., is project engineer on the water treatment team at Alan Plummer Associates Inc. in Fort Worth, Texas. Steven J. Duranceau, Ph.D., P.E., is associate professor of environmental engineering in the civil, environmental, and construction engineering department at the University of Central Florida in Orlando.
(Equation 1) TCTMP20°C = TMPT(TCF) = TMPT (µ20°C÷µT) Where, • TCTMP20°C is the TMP temperature corrected to 20 °C • TMPT is the TMP recorded at temperature T • µ20°C is the absolute viscosity at 20°C • µT is the absolute viscosity at temperature T The operating TCTMP is dynamic with respect to time and influenced by both mass removal during filtration and the development of “irreversible” fouling. Here, irreversible fouling is defined as fouling that is unresolved by physical or chemical maintenance and is characterized using postbackwash and postCEB TCTMP values. Accordingly, the postbackwash TCTMP reports the operating pressure after a backwash and incorporates membrane fouling that was not resolved by physical separation. Likewise, the post-CEB TCTMP reports the operating pressure after a CEB and incorporates chemically unresolved fouling development. Postbackwash and postCEB TCTMP values may be used to determine items such as the frequency of maintenance events and the need for more intensive chemical clean-in-place (CIP) procedures. Implementation of Data Analysis to Assess Performance Changes An investigation of the impact of different pretreatment options on UF membrane fouling was conducted at the Mission San Jose WTP. Process parameters were held constant during the study to isolate the impact of preContinued on page 40
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Continued from page 38 treated feed water on membrane performance, and the pretreatment performance summary is presented in Figure 1. (Note that the postbackwash TCTMP values reported in the figure represent the last backwash in each cycle). Prior to the pretreatment change, the operating, postbackwash, and post-CEB TCTMP data were in close proximity. These results indicate minimal mass loading during filtration and negligible physically and chemically unresolved fouling development. In contrast, the second pretreatment option enhanced membrane fouling. Variations in the operating TCTMP suggest increased mass loading during filtration, and the elevated post-CEB TCTMP values indicate an increased chemically unresolved fouling tendency. Accordingly, the second pretreatment option increases process operating costs and necessitates a new chemical maintenance protocol.
Process Productivity Benchmarking: Process Recovery, Process Utilization, and Filtrate Encumbrance In direct filtration, the process recovery quantifies the volume of usable filtrate that is not consumed during maintenance events (i.e., backwashes and CEBs). Process recovery values typically range between 95 and 98 percent in drinking water applications (MWH, 2005) and may be calculated using Equation 2. While the process recovery quantifies the fraction of feed water available for downstream processes or distribution, it does not account for the lost production time associated with operating functions such as maintenance events, valve actuations, and integrity tests. A new process utilization term is presented as Equation 3 that benchmarks UF productivity in terms of the theoretic maximum filtrate volume (VFil,Max). Since the calculation of VFil,Max assumes continuous filtrate production at
a constant flux over the duration of operation, any operating function that consumes filtrate or reduces available filtration time encumbers a fraction of the VFil,Max and reduces the process utilization. Thus, the process utilization represents the extent to which the UF process approaches ideal performance. (Equation 2) Percent Process Recovery = [(VFil -VBW -VCEB) ÷ VFeed](100) (Equation 3) Percent Process Utilization = [(VFil -VBW -VCEB) ÷ VFil,Max](100) Where, • VFil is the volume of filtrate produced • VBW is the volume filtrate consumed during backwashes • VCEB is the volume of filtrate consumed during CEBs • VFeed is the volume of feed water • VFil,Max is the theoretical maximum filtrate production
Dynamic Operation
Figure 1. Mission San Jose Ultrafiltration Pilot: Process Assessment Table 1. Test Plan
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Systematic Approach to Dynamic Operation A pilot-scale test of dynamic process operation was conducted at the Lake Manatee WTP. The primary test goal was to increase productivity while maintaining sustainable process performance. To accomplish this goal, a systematic approach was taken to incrementally increase process recovery and utilization by varying a single operating parameter at a time and monitoring performance. Table 1 presents a summary of the different operating configurations evaluated during testing, with parameters in bold indicating a change from the previous parameter value. As shown in the table, the initial operating configuration (Configuration 1) had process recovery and utilization values of 92.0 percent and 87.2 percent, respectively. Increases in the recovery and utilization were achieved by altering the backwash duration, CEB frequency, and filtration duration within the acceptable range of values recommended by the membrane manufacturer. These parameters were selected based on an evaluation of filtrate encumbrance and a desire to decrease chemical use. Figure 2 presents the results of the initial filtrate encumbrance evaluation for the UF pilot. Routine backwash events encumbered 9.51 percent of the VFil,Max (inclusive of valve actuation), whereas CEBs encumbered a total of 3.03 percent. Accordingly, it was determined that the most significant filtrate production improvements could be achieved by altering the backwash protocol (Configuration 2). A decrease in the CEB frequency in Configuration 3 yielded
an additional productivity improvement while halving chemical consumption, and the final three configurations increased process recovery and utilization by incrementally extending the filtration duration from 45 to 75 min. Assessing Performance During Dynamic Operation Figure 3 presents the postbackwash and post-CEB TCTMP data for the six operating configurations. Configuration 1 has been subdivided into two parts to reflect differences in the CEB chemical protocols. The initial CEB protocol called for consecutive citric acid and sodium hypochlorite CEBs; however, an injection issue limited the pilot to sodium hypochlorite CEBs only. The CEB system was repaired for Configuration 1b, and sodium hydroxide was added to the sodium hypochlorite solution to elevate the pH above 10. The new CEB protocol successfully reduced the chemically unresolved fouling developed during Configuration 1a and maintained stable post-CEB TCTMP values. Table 2 presents a summary of the average post-CEB TCTMP data for the six operating configurations. Post-CEB TCTMP values generally increased marginally with increasing process recovery and utilization. However, a two-week pilot shutdown prior to the start of
Configuration 5 resulted in a slight reduction in chemically unresolved fouling relative to Configuration 4. The 75-min filtration time in Configuration 6 yielded the highest average post-CEB TCTMP, and the plot of post-CEB TCTMP versus runtime in Figure 3 indicates an upward trend in chemically unresolved fouling development.
The TMP required to maintain constant flux production influences UF process operating costs. Figure 4 provides a percentage-based distribution of the TCTMP values recorded during each configuration. The poor CEB performance of Configuration 1a is reflected in the elevated operating pressures observed at Continued on page 42
Figure 2. Filtrate Encumbrance for Configuration 1
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Continued from page 41 the start of testing. In Configuration 2, decreasing the backwash duration by 20 seconds did not significantly affect operating pressures; however, the subsequent reduction in CEB frequency (Configuration 3) resulted in a greater percentage of TCTMP values between the range of 2.17 to 2.67 pounds per sq in. (psi). Configuration 6 yielded the highest operating
pressures as a result of chemically unresolved fouling development and greater mass accumulation during the extended filtration time. Recommended Operating Configuration The criteria for selecting an operating configuration were ranked in the following order of importance: (1) demonstration of sustainable performance, and (2) process recovery and uti-
Table 2. Lake Manatee Ultrafiltration Pilot Chemically Enhanced Backwash Assessment
lization values greater than 95 percent and 92 percent, respectively. These goals were intended to allow for an acceptable level of filtrate production, while assessing the feasibility of minimizing chemical use and CIP frequency. The pilot test results show that operating Configurations 4â&#x20AC;&#x201C;6 achieved the process recovery and utilization targets. However, Configuration 6 yielded the highest average post-CEB TCTMP values and operating pressures. The consecutive upward trend in post-CEB TCTMP values for Configuration 6 may also have indicated the start of a chemically unresolved fouling trend. Based on these results, Configuration 5 was identified as the most sustainable and productive option. Figure 5 presents the filtrate encumbrance for Configuration 5. The changes to the backwash duration, CEB frequency, and filtration duration decreased the filtrate encumbrance of the backwash from 9.51 to 5.14 percent. Total CEB encumbrance also improved with a decrease from 3.3 to 1.01 percent of the VFil,Max. These productivity improvements are reflected in the volume of filtrate produced per UF module, as shown in Figure 6. Under operating Configuration 5, net filtrate production was increased by 9,472 gal/week to 137,858 gal/week. Operating Configuration 6 would have yielded an additional 1,707 gal/week per module relative to Configuration 5, but may also have increased CIP frequency.
Conclusions and Recommendations
Figure 3. Lake Manatee Ultrafiltration Pilot: Process Assessment
The dynamic operation of a surface water UF pilot successfully increased membrane productivity, while maintaining sustainable fouling management. A systematic test plan was developed using the concept of filtrate encumbrance, and membrane performance was evaluated using operating, postbackwash, and post-CEB TCTMP values. Using these techniques, process recovery and utilization values of 96.2 percent and 93.7 percent were achieved. A site-specific cost-benefit analysis is recommended to enhance decision making relative to dynamic process operation. This economic analysis component should focus on identifying the tradeoffs between operating costs and filtrate production at increasing process utilization values.
Acknowledgments
Figure 4. Lake Manatee Ultrafiltration Pilot: Operating TCTMP Distribution
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The research reported herein was funded by UCF project agreements 16208085 and 16208088. Thanks are in order for the companies and municipalities involved in the acquisition, maintenance, and support activities associated with the two ultrafiltration pilots. The contributions of Harn R/O Systems Inc. (Venice, Fla.), Horizon Industries Inc. (Las Vegas, Nev.),
Toyobo CO. Ltd. (Osaka, Japan), the Alameda County Water District (Fremont, Calif.), and Bruce MacLeod, Mark Simpson, Katherine Gilmore, Bill Kuederle, and others of the Manatee County Utilities Department (Bradenton, Fla.) are duly recognized and greatly appreciated. Additional thanks are offered to Dr. Jayapregasham Tharamapalan for his dedicated assistance with pilot testing activities.
References • Bacchin, P., Aimar, P., & Field, R.W. (2006). Critical and sustainable fluxes: Theory, experiments and applications. Journal of Membrane Science, 281, 42-69. • Boyd, C.C., & Duranceau, S.J. (2012). Assessing and maintaining membrane performance in a post-sedimentation ultrafiltration process. Water Practice & Technology, 7(2). doi: 10.2166/wpt.2012.041 • Campinas, M., & Rosa, M. J. (2010). Assessing PAC Contribution to the NOM fouling control in PAC/UF Systems. Water Research, 44, 1636-1644. • Duranceau, S.J. & Taylor, J.S. (2011). Membranes. In J. K. Edzwald (Ed.), Water quality and treatment: A handbook on drinking water (6th ed.). New York, NY: McGraw-Hill. • Field, R.W., Wu, D., Howell, J.A., & Gupta, B.B. (1995). Critical flux concept for microfiltration fouling. Journal of Membrane Science, 100, 259-272. • Gao, W., Liang, H., Ma, J., Han, M., Han, Z., & Li, G. (2011). Membrane fouling control in ultrafiltration technology for drinking water treatment production: A review. Desalination, 272, 1-8. • Howe, K.J., & Clark, M.M. (2006). Effect of coagulation pretreatment on membrane filtration performance. Journal of the American Water Works Association, 98(4), 133-146. • Howell, J.A. (1995). Sub-critical flux operation of microfiltration. Journal of Membrane Science, 107, 165-171. • Huang, H., Schwab, K., & Jacangelo, J.G. (2009). Pretreatment for low pressure membranes in water treatment: a review. Environmental Science & Technology, 43(9), 3011-3019. • Katsoufidou, K., Yiantsios, S.G., & Karabelas, A.J. (2008). An experimental study of UF membrane fouling by humic acid and sodium alginate solutions: The effect of backwashing on flux recovery. Desalination, 220, 214-227. • Kim, J., & DiGiano, F.A. (2006). A two-fiber, bench-scale test of ultrafiltration (UF) for investigation of fouling rate and characteristics. Journal of Membrane Science, 271, 196-204. • Liu, C., Caothien, S., Hayes, J., Caothuy, T., Otoyo, T., & Ogawa, T. (2006). Membrane chemical cleaning: From art to science. (Pall
Figure 5. Filtrate Encumbrance for Configuration 5
Figure 6. Comparison of Net, Total, and Maximum Filtrate Production
•
•
•
•
Corporation). Retrieved from http://www.pall.com/pdfs/Water-Treatment/mtcpaper.pdf MWH. (2005). Water treatment: Principles and design (2nd ed.). In J.C. Crittenden, R.R. Trussell, D.W. Hand, K.J. Howe, & G. Tchobanoglous (Eds.). Hoboken, NJ: John Wiley & Sons. Ouyang, Y., Nkedi-Kizza, P., Wu, Q.T., Shinde, D., & Huang, C.H. (2006). Assessment of seasonal variations in surface water quality. Water Research, 40, 3800-3810. Porcelli, N., & Judd, S. (2010). Chemical cleaning of potable water membranes: A review. Separation and Purification Technology, 71, 137-143. Smith, P.J., Vigneswaran, S., Ngo, H.H., BenAim, R., & Nguyen, H. (2006) A new approach to backwash initiation in membrane systems. Journal of Membrane Science, 278, 381-389.
• Strugholtz, S., Sundaramoorthy, K., Panglisch, S., Lerch, A., Brügger, A., & Gimbel, R. (2005). Evaluation of the performance of different chemicals for cleaning capillary membranes. Desalination, 179, 191-202. • United States Environmental Protection Agency. (2005). Membrane filtration guidance manual, EPA 815-R-06-009, Office of Water, Washington, DC. • Wu, D., Howell, J.A., & Field, R.W. (1999). Critical flux measurement for model colloids. Journal of Membrane Science, 152, 89-98. • Yuan, W., & Zydney, A.L. (2000). Humic acid fouling during ultrafiltration. Environmental Science & Technology, 34 (23), 5043-5050. • Zondervan, E., & Roffel, B. (2007). Evaluation of different cleaning agents used for cleaning ultra filtration membranes fouled by surface water. Journal of Membrane Science, 304, 40-49.
Florida Water Resources Journal • November 2013
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C FACTOR
Water and Wastewater Expo and Membership Provide Training and Professional Development Jeff Poteet President, FWPCOA
job, working together to put on this outstanding training event.
Benefits of Membership he sixth annual Southwest Florida Water and Wastewater Expo went off without a hitch. This event, put on by the local chapters of FWPCOA, the Florida Section of AWWA (FSAWWA), and the Florida Water Environment Association (FWEA), was the most successful Expo yet! The event had three morning training tacks, followed up by two training tracks in the afternoon. Over 100 students registered for the training. Both continuing education credits (CEUs) and professional development hours (PDHs) were awarded to those students. The exposition hall had over 60 vendors and an estimated 350 people walked the floor. The photos here show various activities at the Expo. Several volunteers and all of the instructors, including Jason Sciandra, with the FWEA-Southwest Chapter; Ron Cavalieri, with FSAWWA-Region V; and Jon Meyer, with FWPCOA-Region VIII, did an outstanding
T
A new fiscal year is upon us. As you know, FWPCOA is the industry's best networking organization for operators and technicians within Florida. As a member of FWPCOA, you: Receive a subscription to the Florida Water Resources Journal. This is a monthly publication jointly sponsored by FWPCOA, FSAWWA, and FWEA. This publication keeps its subscriber's abreast of current events in Florida's water and wastewater professions. Receive discounts on residency training courses provided by FWPCOA. Whether you work in the public or private sector, you can't afford to let technology pass you by. As you know, CEUs are mandatory with license renewals, and many utilities recognize FWPCOA certifications as increasing your eligibility for new jobs or promotions. Get a chance to visit other utilities in your area: network with your fellow industry
(photos: Mike Ehlen, FWPCOA-Region 8)
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November 2013 â&#x20AC;˘ Florida Water Resources Journal
workers, establish contacts, and make new friends. This is a great time to set up a group membership for your organization. A group membership will save you time from doing renewals individually and will help assure that your team has available to them the resources they need to excel.
Short School Schedule Your association is already gearing up for our Spring State Short School. The school will be held on March 24-28, 2014, at the Indian River State College in Ft. Pierce, which is where the school has been held the last few years. Mark the date on your calendars now, and more information on the school will be forthcoming.
Career Kudos As president of this outstanding organization, I get the pleasure to recognize those people in our industry that have done some outstanding things. I would like to recognize one of my
team members who will be retiring from our industry later this month: Ronald Weis. Ron began his career in the drinking water industry in 1983 as an operator trainee for the Deltona Corporation on Marco Island. Ron’s intrinsic hunger for knowledge helped him quickly gain the understanding of the water treatment process, and he rapidly rose to a leadership position in the utility. In 1990, Ron was put in charge of a new treatment expansion project: a high-pressure reverse osmosis (RO) treatment plant. In 1991 Ron earned a Class “A” drinking water license from the state of Florida and the RO plant went online in April of 1992. In an effort to improve operational efficiencies and reduce membrane fouling, booster pumps were added to the second stage of the process—the first application of this type in the United States. Today, this process is utilized universally! Although the utility’s ownership has changed several times during Ron’s career (it’s currently owned and operated by the City of Marco Island), he has continued to work at this facility. On November 8 of this year, after 30 years of service, Ron will be retiring from the utility. Through Ron’s efforts, the facility has been recognized for outstanding operational performance and safe work practices throughout his tenure. Although this chapter of Ron’s life will be closed, new opportunities will arise—and perhaps the Association will be able to tap into Ron’s expertise! Congratulations Ron, on an outstanding career!
Nominations Sought I mentioned this in my last article, but I believe it’s worth mentioning again: the FWPCOA nominating committee has nominated the current slate of officers to continue in their rolls in 2014. Nominations will also be encouraged from the floor during the November board meeting prior to the election. Those wishing to present a floor nomination should review the relevant bylaw sections carefully, as they need to be meticulously followed. The state bylaws can be found online at www.fwpcoa.org. Please keep in mind that this is your Association. If you’re not involved in the organization, we would love for you to become engaged. Your involvement will directly benefit the industry and may help you in your professional endeavors. For regional contact information please check out our website, look for the region that you belong to, and you’ll find the information you need. The November board meeting will be held in Daytona Beach on November 16. I hope to see you there! Florida Water Resources Journal • November 2013
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Florida Teams Compete in Operations Challenge at WEFTEC At the 2013 Florida Water Resources Conference in April, two teams earned the honor of representing the state at this year’s Operations Challenge at WEFTEC: “Team GRU” from Gainesville Regional Utilities and City of St. Cloud’s “Methane Madness.” The Water Environment Federation conference was held October 5-10 in Chicago at the McCormick Place Convention Center. The Operations Challenge showcases what operators and technicians do to overcome flooding, a sewer collapse, process failure, or other such emergencies.
The contest was held October 7-8. Teams from all across the United States, sponsored by a WEF member association or recognized operator association, competed in the event. Winners were determined by a weighted point system for five events—collection systems, laboratory, process control, maintenance, and safety—designed to test the diverse skills required for the operation and maintenance of wastewater treatment facilities, collections systems, and laboratories .
Greg Chomic, president of the Florida Water Environment Association, cheered for his state teams.
(photos: Mike Delaney)
The two teams in action during the various phases of the competition; the Gainesville team is in the blue shirts and the team from St. Cloud is wearing black shirts.
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November 2013 • Florida Water Resources Journal
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News Beat Gunster, a business law firm in West Palm Beach, announced that Gregory M. Munson, an attorney and former deputy secretary for water policy with the Florida Department of Environmental Protection, has joined the firm as a shareholder in its Tallahassee office. In his most recent role at the Department, Munson supervised its activities related to the state’s water management districts and coastal and aquatic-managed areas. He acted as one of the lead negotiators for Governor Rick Scott’s $880 million water quality agreement with the federal government, recently codified by the Florida Legislature as the long-term plan for Everglades restoration. He also oversaw revision to Florida consumptive use permitting rules governing all consumptive uses of water in the state. As general counsel, he managed litigation regarding the Clean Water Act and the tri-state dispute over the Apalachicola River. In his new position, he will be a member of Gunster’s environmental and land use practice, concentrating in the area of water use and water rights.
PS Form 3526: Statement of Ownership, Management and Circulation (Required by 39 U.S.C. 3685) (1) Publication Title: Florida Water Resources Journal. (2) Publication Number 0896-1794. (3) Filing Date: 09/30/13. (4) Issue Frequency: Monthly. (5) No. of Issues Published Annually: 12. (6) Annual Subscription Price: $6/members, $24/non-members. (7) Complete Mailing Address of Known Office of Publication: 1402 Emerald Lakes Dr., Clermont, FL 34711. Contact Person: Michael Delaney. Telephone: 352-241-6006. (8) Complete Mailing address of Headquarters or General Business Office: 1402 Emerald Lakes Dr., Clermont, FL 34711. (9) Publisher: Florida Water Resources Journal, Inc. 1402 Emerald Lakes Dr., Clermont, FL 34711. Editor: Rick Harmon, 1402 Emerald Lakes Dr., Clermont, FL 34711. Managing Editor: Michael Delaney, 1402 Emerald Lakes Dr., Clermont, FL 34711(10) Owner: Florida Water Resources Journal, Inc. 1402 Emerald Lakes Dr., Clermont, FL 34711. Stockholders: (33 1/3% each) Florida Water and Pollution Control Operators Association, P.O. Box 109602, Palm Beach Gardens, FL 33410-9602; Florida Section/American Water Works Association, 769 Allendale Rd., Key Biscayne, FL 33149; Florida Water Environment Association, 4350 W. Cypress St. #600, Tampa, FL 33607. (11) Known Bondholders, Mortgages, and Other Security Holders Owning or Holding 1 Percent or More of Total Amount of Bonds, Mortgages, or Other Securities: None. (12) The purpose, function, and nonprofit status of this organization and the exempt status of federal income tax purposes: Has not changed during preceding 12 months. (13) Publication Name: Florida Water Resources Journal. (14) Issue Date for Circulation Data Below: October 2012. Average No. Copies Each Issue During Preceding 12 Months
Actual No. Copies of Single Issue Published Nearest to Filing Date
a. Total No. of Copies (Net Press Run)
7,427
6,975
b. Paid and/or Requested Circulation
0
0
7,352
6,900
7,352 0
6,900
(15) Extent and Nature of Circulation
(1) Sales through dealers and carriers, street vendors and counter sales (not mailed) (2) Paid or requested Mail Subscriptions (Include advertisers proof copies/exchange copies) c. Total Paid and/or Requested Circulation (Sum of 15b(1) and 15b(2) d. Free distribution by Mail (Samples, complimentary, and other free) e. Free Distribution Outside the Mail (carriers or other means) f. Total Distribution (Sum of 15c and 15f) g. Copies Not Distributed h. Total (Sum of 15g and 15g) i. Percent Paid and/or Requested Circulation (15c/15gx100)
0
0 0
7,352
6,900
75
75
7,427
6,975
98.99%
98.92%
(16) This Statement of Ownership will be printed in the November 2013 issue of this publication. (17) Signature and Title Editor, Publisher, Business Manager, or Owner. I certify that all information furnished on this form is true and complete: I understand that anyone who furnishes false or misleading information on this form or who omits material or information requested on the form may be subject to criminal sanctions (including fines and imprisonment) and/or civil sanctions (including multiple damages and civil penalties). Date: 9/30/13
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November 2013 • Florida Water Resources Journal
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November 2013 â&#x20AC;˘ Florida Water Resources Journal
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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
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
w w w. c e nt r a l f l or i d a c ont rol s . c om
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EQUIPMENT & SERVICES DIRECTORY Showcase Your Company in the Engineering or Equipment & Services Directory Contact Mike Delaney at
352-241-6006 ads@fwrj.com
CLASSIFIEDS Positions Av ailable Water Plant Superintendent The City of Miramar Utility Department is seeking qualified candidates for a Water Plant Superintendent. This position is responsible for supervising day to day operations of a potable water treatment plant in the City of Miramar. It requires Florida State Class “A” Operators license and 10 years progressive supervisory experience in water system operations. Starting salary is $48,426 annually. For more information and to apply for this position, please go to the City of Miramar’s employment website at http://www.miramarjobs.us.
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.
Senior Engineer Mathews Consulting is a local South Florida civil engineering consulting firm located in West Palm Beach, Florida. Mathews Consulting is currently seeking a dynamic, team oriented Senior Engineer (min. 10 years civil engineering experience) to play a key role in our growing South Florida practice. Candidate must have a Bachelors degree in Civil or Environmental Engineering and a Florida P.E. license. The types of projects that the candidate will be involved with include water/wastewater, pipelines/pump stations, and hydraulic modeling and engineering for municipal infrastructure and facilities. Responsibilities will include project engineering/design, report writing, project management, construction field visits and interaction with clients. Candidate must be able to work independently and as a team player with excellent computer, communication and organization skills. Competitive salary and comprehensive package including health and life insurance, retirement plan and employee incentives are available. Please send letters of interest and resume to: Rene Mathews, Mathews Consulting Inc., 477 S. Rosemary Avenue, Suite 330, West Palm Beach, Florida 33401. Tel: 561-655-6175. Fax: 561-655-6179. Email: RMathews@mathewsconsultinginc.com
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November 2013 • Florida Water Resources Journal
City of St. Petersburg – Water Maintenance Manager IRC27324 $64,987 - $97,435 DOQ – Open Until Filled; Supervisory, technical work in construction, installation, maintenance and repair of potable and reclaimed water systems; requirements: high school diploma/GED equivalency; State of Florida Drivers License; State of Florida Class "A", "B" or "C" license in Water Distribution and FW & PCOA certificates in Cross Connection Control and/or Reclaimed Water - See detailed requirements, apply online at www.stpete.org/jobs or mail resume to Employment Office, PO Box 2842, St Petersburg FL 33731 EOE/DFWP/Vets.' Pref.
Town of Lake Placid Florida Certified Double “C” Water Treatment Plant and Wastewater Treatment Plant Operator. The Town of Lake Placid is 10 miles south of Sebring, Florida and has 26 beautiful lakes for fishing and recreation. Call 863-699-3748 and ask for Gary Freeman. Download application form at www.lakeplacidfl.net. EOE/DFWP.
City of Clermont OPERATIONS CHIEF Position # 823 The City of Clermont is seeking a Waste Water Operations Chief. Minimum three (3) years supervisory experience in operations, maintenance and repair of public utility wastewater treatment plant. Strong management and computer skills required. Valid FL Drivers license req. Apply to Human Resources Department at: 685 W. Montrose St., Clermont, FL 34711. Resumes will not be accepted without a completed application. Position starting pay- $19.43 Pre-employment physical, drug screen and back ground check required. EOE/Vet Pref/DFWP
Del-Jen, Inc - Water Wastewater Supervisor Del-Jen, Inc is seeking a qualified candidate for a Utilities Water/Wastewater Supervisor. Individual will supervises day to day operations in the following areas: water plant operations, water distribution systems, sewage collection systems, water sampling collections and FDEP regulatory requirements. As a minimum, must have both a current Florida Class "E" driver's license or equivalent and a current Florida Class “A” water plant operator’s certification. See detailed requirements at http://www.del-jen.com/. To apply by mail send resume to Del-Jen, Inc, ATTN: HR, PO Box 33370, Pensacola, FL 32508-5300. EOE
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 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
Utilities Storm Water Supervisor $51,494-$72,457/yr. Plans/directs the maintenance, construction, repair and tracking of stormwater infrastructure. AS in Management, Environmental studies, or related req. Min. five years’ exp. in stormwater operations or systems. FWPCOA “A” Cert. req. Apply: HR Dept., 100 W. Atlantic Blvd., Pompano Beach, FL 33060. Open until filled. E/O/E. Visit www.mypompanobeach.org for details.
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
Indian River County BCC WATER PLANT OPERATOR B Skilled work in the operation of a water plant. This position requires a high school diploma / GED. Must possess a Class B Florida water plant operator's license and a valid Florida driver's license. Must possess knowledge of water operations and basic repair of pumps. Must be able to read meters and charts accurately. Apply: Indian River County Human Resources, 1800 27th Street, Vero Beach, FL 32960. Review full job posting and download employment application at: www.ircgov.com. Fax: (772) 770-5004. EOE/AA.
Positions Wanted BEVERLY BARTA - Seeking position which utilizes skill set and international experience in the water resource sector; Safety Surveys, Services Support, Environmental Reporting/Compliance. MS in Enviro. Engineering (U of F), REM, CESCO, and recent Small Water Systems Laboratory Certification (U of Cal) and FL DEP Class D Water Treatment plant Operator License. email: gator11178@gmail.com www.linkedin/in/beverlybarta
Looking For a Job? The FWPCOA Job Placement Committee Can Help! Contact Joan E. Stokes at 407-293-9465 or fax 407-293-9943 for more information.
Water and Wastewater Utility Operations, Maintenance, Engineering, Management
CLASSIFIED ADVERTISING RATES - Classified ads are $18 per line for a 60 character line (including spaces and punctuation), $54 minimum. The price includes publication in both the magazine and our Web site. Short positions wanted ads are run one time for no charge and are subject to editing.ads@fwrj.com
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Certification Boulevard Answer Key From page 20 1. D) Possible contamination through the atmosphere. Contamination of water through aeration is an associated problem. The other choices listed are all benefits of aeration. The increase in pH assists in iron removal by converting ferrous ion to ferric hydroxid,e and the reduction in hydrogen and carbon dioxide have added benefits such as reducing chemical dosages like chlorine for disinfection.
2. C) Turbidity units Turbidity is a measure of the amount of light reflected by suspended particles, though it is not a measure of the concentration of solids because white particles reflect more light than dark particles. Often expressed as nephelometric turbidity units (NTUs,) water having turbidities greater than 5 NTUs is clearly visible with the naked eye.
3. A) Algae Tastes and odors that have an earthy or grassy smell are generally related to algae. When an algae bloom (rapid and massive increase in algae) occurs, the population eventually dies off and the decaying organic material imparts tastes and odors. Additionally, the decaying algae may create an oxygen demand and lower oxygen levels to a point where anaerobic conditions are created.
Display Advertiser Index American Flow Control ......................19 CEU Challange ..................................27 Crane Pumps ....................................39 Crom ................................................33 Data Flow..........................................31 Elster ................................................10 FSAWWA Conference ..................22-24 FWPCOA Short School ......................35 FWPCOA Training ..............................26 Garney ..............................................13 Gerber Pumps Electro Coagulation ....48 Hudson Pump....................................47 John Meunier ......................................9 Oldcastle ..........................................46 Rangeline..........................................55 Regional Engineering ........................44 Reiss Engineering................................5 Schlumberger ..................................21 Stacon ................................................2 Swan ................................................37 Treeo ................................................17 US Water ..........................................45 Xylem................................................56
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4. D) There are no health effects. There are no direct health effects associated with color. Color due to iron or manganese may cause red water or black staining, but neither have health effects. Sometimes color may be an indicator of other pollutants or contaminates in the water that could cause sickness or disease.
5. B) Bottom of the curve. Most chemicals are water-based and the bottom of the curve of the liquids surface should be used when determining chemical level. There are some exceptions, such as mercury, whose meniscus will actually curve in the opposite direction and form a slight rise in the liquids surface.
6. A) 2 to 3 gpm/sq ft A pressure filter is completely enclosed in a vessel and the water is forced through the media under pressure. Maximum filtration rates are typically 2 to 3 gpm/sq ft (gal per min per sq ft). Exceeding these filtration rates may force solids through the media and result in increased turbidity levels in the finished water.
7. A) Granular activated carbon Granular activated carbon, made from heating carbon such as wood, has high adsorptive properties that allow it to remove tastes and odors from drinking water. The adsorptive properties of activated carbon do not last
indefinitely and the spent carbon must be regenerated or replaced.
8. A) Cavitation Cavitation occurs when pressures drop inside a high-service pump that is in operation. This drop in pressure causes gas pockets to form in the water, which then collapse, causing severe damage to the pump’s interior. This can occur when a pump is trying to deliver more water than it was designed for, commonly called “pumping off the curve.”
9. A) Acidified with nitric acid. Iron samples should be acidified with nitric acid to reduce the pH to <2. This ensures that the iron stays insoluble and does not form a scale buildup on the container wall,s resulting in an erroneously low iron result.
10. D) Remove moisture from lab samples. The desiccator is an apparatus for absorbing the moisture present in a substance. Typically, the substance is placed in an enclosed box, which contains a desiccant (drying agent) that removes humidity (water) from the atmosphere.
Thank you to Scott Ruland, chief operator with the City of Deltona, for providing these questions and answers.
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.
November 2013 • Florida Water Resources Journal