Environmental Science & Engineering Magazine | April/May 2020 by Environmental Science and Engineering Magazine

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CONTENTS

April/May 2020 • Vol. 33 No. 2 • ISSN-0835-605X

Editor and Publisher STEVE DAVEY steve@esemag.com Managing Editor PETER DAVEY peter@esemag.com Sales Director PENNY DAVEY penny@esemag.com ales Representative DENISE SIMPSON S denise@esemag.com Accounting SANDRA DAVEY sandra@esemag.com Design & Production MIGUEL AGAWIN production@esemag.com

Circulation BRIAN GILLETT ese@mysubscription.ca

TECHNICAL ADVISORY BOARD

FEATURES

Archis Ambulkar, OCT Water Quality Academy Gary Burrows, City of London Patrick Coleman, Black & Veatch Bill De Angelis, Metrolinx Mohammed Elenany, Urban Systems William Fernandes, City of Toronto Marie Meunier, John Meunier Inc., Québec Tony Petrucci, Civica Infrastructure

6 Canada well served by water, wastewater and environmental professionals during the COVID-19 pandemic 8 What water treatment professionals need to know about coronavirus and the water cycle – Cover story 12 Managing environmental risk during these uncertain times 16 New fluid bed municipal biosolids incinerator and dryer meet updated emission limits 20 New technique could accelerate methane production from FOG and food wastes 22 Geotextile system provides long-term biosolids management savings for small town 26 Evaluating treatment options for removing PFAS from drinking water 30 Automatic self-cleaning filters allow Alberta county to stretch its potable water supply 32 Cambridge adopts preventative water loss program with acoustic leak detection technology 34 Helping utilities and municipalities manage stormwater and green infrastructure 38 Removing CECs from cold water post-lagoon wastewater treatment systems 41 Water well drilling takes careful preparation and experience 44 How to reduce the risk of I/I in new sanitary sewers from the private side 48 Canada needs more provincial regulations for perand polyfluoroalkylated substances 52 How to prevent the many types of heat exchanger fouling 57 Exploring treatment options to remove new contaminants in landfill leachate

Environmental Science & Engineering is a bi‑monthly business publication of Environmental Science & Engineering Publications Inc. An all Canadian publication, ES&E provides authoritative editorial coverage of Canada’s municipal and industrial environmental control systems and drinking water treatment and distribution. Readers include consulting engineers, industrial plant managers and engineers, key municipal, provincial and federal environmental officials, water and wastewater plant operators and contractors. Information contained in ES&E has been compiled from sources believed to be correct. ES&E cannot be responsible for the accuracy of articles or other editorial matter. Articles in this magazine are intended to provide information rather than give legal or other professional advice. Canadian Publications Mail Sales Second Class Mail Product Agreement No. 40065446 Registration No. 7750 Subscription Changes? Please email reader subscription changes to ese@mysubscription.ca, or call 705-502-0024. Environmental Science & Engineering 220 Industrial Pkwy. S., Unit 30 Aurora, Ontario L4G 3V6 Tel: (905)727-4666 Website: www.esemag.com

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EDITORIAL COMMENT BY STEVE DAVEY

Canada well served by water, wastewater and environmental professionals during the COVID-19 pandemic

n his writings, French author Fernand Braudel stressed that every human born before the 20th century, with its technical, medical and scientific advances, would have been lucky to have lived. As he put it, before this time the world was a brutal, disease-ridden and hungry place for its inhabitants, most of whom had short life expectancies. It is common for writers to use cathedrals, castles, or other architecturally advanced buildings as the mark of a great civilization. However, it was the sewers, waterworks and waste treatment schemes of the early pioneers in these sectors that did much to rid us from typhoid, paratyphoid, cholera, etc. There is no denying that the COVID-19 pandemic has caused significant social and economic issues, as well as the tragic loss of lives around the globe. However, during this time I have not heard anyone question the reliability and continuity of their municipal water or sewerage systems. While there are always public concerns about water quality, such as high levels of lead, etc., the fear of water not flowing on demand rarely comes up. Canadians blissfully assume water will flow to their taps and that their toilets will flush, regardless of what is happening in the world outside. It is a testament to the generations of designers, builders, owners, managers and operators, that our water and wastewater systems rarely fail. Even when they do, it is largely localized. But what effect is COVID-19 having on our water and wastewater systems and the dedicated men and women who operate them? In the article “What treatment professionals need to know about coronavirus and the water cycle” (Page 8), the authors explain that infectious human coronaviruses may be present in raw wastewater that is collected from a population where an infection is occurring. Also, that if wastewater treatment is insufficient to remove or inactivate coronaviruses, or combined sewer overflows/bypasses are operational, these viruses may be released into the environment. Surface water treatment plants with upstream wastewater plants are the most susceptible to having coronaviruses contaminate the raw water supply during, and after, an outbreak. However, research has shown that conventional water treatment with sufficient free available chlorine for disinfection can reduce virus levels to a safe amount. Water and wastewater operators have always worked with harmful bacterial and viral agents. Respiratory illnesses can be spread by contact with aerosols and by hand-to-mouth transmission. Therefore, it is recommended that they use barriers, such as face masks and disposable gloves, to prevent

6 | April/May 2020

exposure to aerosols. Furthermore, strict sanitation practices should be implemented. Canada’s industrial sector too has had to deal with many issues surrounding COVID-19. While many companies have been deemed essential services, most are shuttered. In the article “Managing environmental risk during these uncertain times” (Page 12), Janet Bobechko gives practical suggestions on how to integrate environmental compliance information that can be used to assist companies to check their compliance status. Bobechko adds that “many companies find themselves operating at minimal levels, ceasing operations, operating at capacity, or being asked to identify potential maximum capacity.” Such companies should ensure they consult their internal teams to understand the obligations for ceasing or expanding operations, including notification to regulators if changes occur. Bobechko also stresses that it is important to review emergency and spill reporting protocols and to check with emergency response contractors to ensure they are still operational and can respond if needed. This is indeed a strange time to live in. The necessary cancellation or postponement of traditional conferences, tradeshows, etc., does not mean that we can’t continue to share ideas, support and advice. Canada’s water, wastewater and environmental sectors continue to demonstrate a level of professionalism that is second to none. See you all on the other side. Steve Davey is the editor and publisher of ES&E Magazine. Please email any comments you may have to steve@esemag.com.

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What treatment professionals need to know about coronavirus and the water cycle By Nicole McLellan, David Pernitsky, Arthur Umble and Joseph Jacangelo

toms of diarrhea and the virus is capable of binding to receptors in the intestines as well as in the lungs (Leung et al., 2003). These viruses may be detected in urine and stools from infected individuals for more than 100 days after initial infection (Liu et al., 2003). The persistence of coronaviruses in hospital wastewater CONSIDERATIONS FOR WATER and domestic sewage is estimated to be AND WASTEWATER TREATMENT 2 – 3 days (Wang et al., 2005). Wastewater treatment plants that are Infectious human coronaviruses may be present in raw wastewater that is receiving sewage from hospitals and isocollected from a population where an lation centres treating patients for coronainfection is occurring. About 20–40% of viruses may have elevated concentrations SARS-CoV infections presented symp- of viruses in their wastewater influent. Waste Water products plus NMac 4.65 x 4.65.pdf 1 1/24/2018 7:37:09 AM Furthermore, if wastewater treatment is insufficient to remove or inactivate coronaviruses, or combined sewer overflows/ bypasses are operational, the viruses may Pumps for all your waste water challenges be released into the environment (Casanova et al., 2009).  Thickened Sludge  Bio-mass  Thin Sludge Coronaviruses have not been found  Dewatered Sludge  Activated Sludge  Lime Milk to be more resistant to water treatment  Auxiliary Flocculents  Combined Sewage  Flotation Sludge than other microorganisms such as E. coli and phage, or human viruses such CLASSIC TORNADO® T1 as poliovirus. These are commonly used Rotary Lobe as surrogates for treatment performance Pumps evaluations (Gundy et al., 2009). Results from bench-scale studies suggest that the survival of coronaviruses is temperaNEMO® Progressing ture dependent, with greater survival at N.Mac™ Twin Cavity Pumps lower temperatures. Therefore, the perShaft Grinders sistence of coronaviruses is expected to Full Service-in-Place be reduced in raw wastewater and sur(FSIP®) Pumps face waters during warmer seasons. ® Common disinfection methods used TORNADO® T2 NEMO Mini Rotary Lobe Pumps Metering Pump in water and wastewater treatment are expected to be effective for inactivation of coronaviruses, when executed properly.

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WASTEWATER TREATMENT In general, secondary wastewater treatment may be credited with removing 1 log (90%) of viruses. However, broad studies suggest the level of virus continued overleaf…

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Environmental Science & Engineering Magazine

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Viruses may be transported through the municipal wastewater system to the wastewater treatment plant.

Combined Sewer Overflow events may lead to the release of infective viruses in untreated wastewater to surface waters.

Workers should follow routine safe work practices and wear proper personal protection equipment.

Viruses in human waste enter the wastewater collection system. Toilet flushing or problems with indoor plumbing systems may produce airborne droplets that could result in human exposure.

Current municipal drinking water treatment and disinfection practices are effective at producing safe water free of coronaviruses.

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removal is highly variable between insignificant removal, to greater than 2 log removal (99%) (Hewitt et al., 2011; USEPA, 1986). Because of this variability, the primary process for the inactivation of viruses in wastewater treatment is chemical disinfection (i.e., chlorination) and/or disinfection by ultraviolet (UV) light. The efficacy of chlorination for inactivating viruses in wastewater is dependent upon numerous water quality factors. Of particular importance is the presence of disinfectant-demanding substances and in particular, ammonia, which reacts with chlorine to form chloramines. In general, chloramines are much poorer virucides as compared to free available chlorine. Thus, it is important to consider the level of ammonia before the disinfection process to adequately determine its virucidal efficiency. Chemical disinfection of wastewater with free available chlorine is expected to be effective for coronaviruses when applied at adequate levels. In one published research study, chlorination of 10 | April/May 2020

Intake water at drinking water treatment plants may potentially contain infective viruses.

domestic wastewater using a dose of 10 mg/L sodium hypochlorite, a contact time of 30 minutes, and a free chlorine residual of >0.4 mg/L was found to inactivate 5 log of coronaviruses (Wang et al., 2005). This level of free chlorine disinfection may not be present in all fullscale WWTPs, where there is ammonia present in the treated effluent. The efficacy of UV disinfection of viruses in wastewater is highly dependent upon the fluence achieved by a particular system and it is therefore not possible to estimate for general systems. For UV disinfection systems that were not designed specifically for virus inactivation, only low-levels of coronaviruses inactivation are expected. BIOSOLIDS MANAGEMENT The survival of coronaviruses in wastewater biosolids has not been reported. However, it is expected to vary significantly depending on site-specific biosolids handling and treatment procedures. Based on a study examining survival of coronaviruses in water and wastewater (Gundy

et al., 2009), coronaviruses survival in primary wastewater effluent at temperatures greater than 20°C is expected to be very low – within a period of four days. However, this same study reported that the survival time increases (e.g., more than four weeks) at cold temperatures (near 4°C) in clean water. At all temperatures studied, coronaviruses showed lower survival rates in wastewater than other viruses. Biosolids handling and disposal practices should be reviewed on a case-by-case basis to prevent contamination of ground and surface waters. The U.S. Environmental Protection Agency’s (EPA) Part 503 rule provides comprehensive requirements for the management of biosolids generated during the process of treating municipal wastewater. PROTECTING WASTEWATER TREATMENT OPERATORS Respiratory illnesses can be spread by contact with aerosols and by hand-tomouth transmission. Therefore, it is recommended that wastewater treatment

Environmental Science & Engineering Magazine

operators and biosolids handlers use barriers, such as face masks and disposable gloves, to prevent exposure to aerosols. Further, strict sanitation practices should be implemented to encourage frequent handwashing, the separation of eating areas from work areas, and minimization of contact between hands and face. Communications should be sent to plant operators and staff to inform them of best sanitation practices. The same do’s and don’ts of general sanitation practices constantly being promoted to the general population to prevent the spread of respiratory viruses apply to operators as well. DO’S • Do wash hands with soap and water for at least 20 seconds, especially after using the bathroom, before eating, after blowing your nose, coughing or sneezing. • Do stay home when you are ill. • Do cover your cough or sneeze with a tissue and dispose of the tissue in the trash. • Do disinfect frequently touched objects and surfaces such as door knobs. DON’TS • Don’t touch your eyes, nose and mouth with unwashed hands. • Don’t have close contact with people who are ill.

Based on published research, water treatment processes that meet virus removal/inactivation regulations are expected to be effective for coronaviruses control.

DRINKING WATER TREATMENT Surface water treatment plants with upstream wastewater impacts are the most susceptible to having coronaviruses contaminate the raw water supply during, and after, an outbreak. Conventional treatment with free available chlorine designed to provide 0.5 log inactivation of Giardia can achieve at least 8 log inactivation of viruses in general (Health Canada, 2019a). It is important to ensure that disinfection performance is continuously monitored (e.g., turbidity, disinfectant dose, residual, pH, temperature, and flow). Optimized conventional filtration can achieve 2 log (99%) virus removal (Health Canada, 2019b). A UV fluence of 44 mJ/cm2 can achieve up to 3 log (99.9%) inactivation of poliovirus 1 and rotaviruses. A dose of 40-199 mJ/cm2 can inactivate up to 3 log (99.9%) of adenoviruses, the most UV resistant viruses (Health Canada, 2019b; USEPA 2006).

Based on published research, water treatment processes that meet virus removal/inactivation regulations are expected to be effective for coronaviruses control. Further details of the efficacy of various treatment processes for the removal/inactivation of human viruses was recently updated in the Guidelines for Canadian Drinking Water Quality (Health Canada, 2019b). Nicole McLellan, David Pernitsky, Arthur Umble and Joe Jacangelo are with Stantec. For more information email nicole.mclellan@stantec.com, david.pernitsky@stantec.com, arthur.umble@stantec.com or joseph.jacangelo@stantec.com For a list of references cited in this article, visit: www.esemag.com/stanteccoronavirus-resources

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SPECIAL FOCUS: COVID-19

up response teams to deal with emergency amendments. Your local ministry contact is the best place to start. In Quebec, companies that temporarily modify their production to supply a new product related to efforts to combat COVID-19 could benefit from an exemption.

Managing environmental risk during these uncertain times By Janet Bobechko

uring the current pandemic, there are many competing priorities, including environmental legal obligations that remain in force. At the same time, the pandemic will create new challenges in fulfilling these duties. However, there are practical suggestions on how to integrate environmental compliance information that can be used to assist companies to check their compliance status.

COVID-19 TEAMS Many companies have established COVID-19 teams. Ensure environmental issues are on the team’s radar and include someone (and an alternate) knowledgeable about environmental matters. It is important to keep in contact with outside experts and contractors to understand their availability. Many contractors have already given force majeure notices, pursuant to pre-existing contracts, that they may not be able to provide their regular services.

12 | April/May 2020

REVIEW ENVIRONMENTAL APPROVALS, LICENSES AND PERMITS Many companies find themselves operating at minimal levels, ceasing operations, operating at capacity, or being asked to identify potential maximum capacity. Ensure you consult your internal teams to understand the obligations for ceasing or expanding operations, including notification to regulators if changes occur. In Quebec, companies that temporarily increase their production to supply essential products related to efforts to combat COVID-19 could benefit from an exemption. EMERGENCY AMENDMENTS TO APPROVALS Many companies require amendments to their approvals to change their operational requirements. If you find that your company is in such position, you should communicate with your regulator the need for a change. Ministries are setting

REPORTING AND COMPLIANCE DEADLINES It is important to confirm deadlines for all approvals and regulatory requirements. Many annual reports are due on March 31 for the prior year. Administrative orders may also have timelines and reporting obligations set out in them. Missing a deadline in an approval or an order is an offence. Official guidance, at the time of publication, is only available for Alberta and Quebec who have each modified certain reporting obligations. We continue to monitor the provinces, territories and federally for any changes. Companies should assess their ability to meet any regulatory or compliance deadline. If there is a concern that a deadline will not be met due to COVID-19 impacts, an immediate written request should be made for an extension from the local district office and authorized officers. While Alberta and British Columbia have deemed engineers an essential service, Ontario has deemed businesses that deliver or support the delivery of certain “community services”, rather than listing specific professional designations. Quebec has deemed “enterprises inv olved in environmental emergencies” and enterprises performing “maintenance and operation of strategic infrastructures” to be priority services. Despite this, many engineering offices are only working remotely. This may hinder access to necessary supports to complete reports and make filing deadlines that require a physical stamp from an engineer. DESIGNATION AS AN ESSENTIAL SERVICE If your company has been designated an essential service and continues to operate, then it’s important to understand what continued overleaf…

Environmental Science & Engineering Magazine

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other services are also essential. Ontario and Quebec have designated essential services restrictions that came into force on March 24 at 11:59 p.m. On April 3 Ontario significantly red uced the number of essential services from 74 down to 44. On March 25 at 12:01 a.m. Quebec made changes. Alberta’s order and list were released on March 27 and became effective immediately. British Columbia also announced what it considered to be essential services. We note that generally, the environmental industry sector should largely be available to help companies continue their operations.

are working remotely, there are still regulatory inspections and investigations taking place. Ensure you have a protocol in place for regulatory inspections and investigations. You should also add a new question about COVID-19 self-assessments (i.e., similar questions for all visitors: Have they recently travelled? Do they meet any of the assessment criteria for COVID-19 testing?). It’s important that this policy is enforced. If the answer is yes, then ask for another officer to conduct the inspection/ investigation. Proactive communication is a way to inform your local officer about current operations and precautions being taken during this challenging time. It may also be useful in a subsequent due diligence defense should the need arise.

DUE DILIGENCE It is important during this time to consider communicating proactively with EMERGENCY AND SPILL RESPONSE your regulator on potential compliance con- REPORTING Review your emergency and spill cerns. While many government employees

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reporting protocols. Confirm that the people who will respond and report any spill or emergency are still available. Consider adding alternate contact information. Confirm that on-site emergency response supplies are adequately stocked. Check with your emergency response contractors to ensure they are still operational and can respond. If not, then seek alternative contractors. With constantly changing staffing levels at some companies and workforces reduced due to self-isolation and self-quarantine, ensure clear communication exists to ensure how environmental compliance and emergency response are managed. CIVIL LITIGATION, PROVINCIAL OFFENCES AND REGULATORY PROCEEDINGS In Ontario, pursuant to an order under s. 7.1 of the Emergency Management and Civil Protection Act (the Suspension Order), all provincial limitation periods for civil lawsuits have been temporarily suspended for the duration of Ontario’s declared state of emergency, retroactive to March 16, 2020. Likewise, subject to the discretion of the applicable court, tribunal or decision-maker, all deadlines in pending civil, Provincial Offences Act, and regulatory proceedings have been temporarily suspended. Notwithstanding the Suspension Order, the Ontario Superior Court of Justice and Ontario Court of Appeal continue to hear urgent civil matters. The Ontario Court of Justice, however, has suspended all Provincial Offences Act matters scheduled until May 29, 2020. Finally, the Environmental Review Tribunal (the ERT) has stated it is postponing and rescheduling in-person hearings. The ERT is using alternative hearing options such as written and telephone hearings where feasible and is using its discretion under the Suspension Order to suspend procedural time periods for matters before it in an effort to continue delivering services and minimizing disruption. In Quebec, under Order No. 2020-004 of the minister of health and social services issued on March 15 (the First Health and Social Services Order), any hearing scheduled before a court of justice, administrative tribunal or other adminis-

Environmental Science & Engineering Magazine

trative body must be held behind closed doors unless the decision-making authority decides otherwise. Pursuant to a subsequent order issued on March 23, Order No. 2020-009 of the minister of health and social services (the Second Health and Social Services Order), certain time limits provided for in the Code of Penal Procedure are suspended except for cases deemed urgent by the courts. Furthermore, the Second Health and Social Services Order provided that despite articles 96 and 103 of the Code of Penal Procedure, any search may be authorized by telephone warrant. In British Columbia, the Court of Appeal for British Columbia and Supreme Court of British Columbia have generally adjourned all hearings scheduled to occur before May 1. The Supreme Court will hear matters that, upon a party’s request, are determined to be essential and urgent. The Court of Appeal will only be hearing appeals the court deems as matters that must proceed. On March 26, the minister of public safety and solicitor general issued ministerial order No. M086, pursuant to the Emergency Program Act. This order suspends every mandatory limitation period within which a civil action, proceeding, claim or appeal must be commenced in the Provincial Court, Supreme Court or Court of Appeal, effective March 26

Review operational temporary closure plans to ensure critical operations are managed appropriately and that key contractors who may be required to assist in any closure continue to be available. Some regulators have taken to conducting consultations on-line instead of in person. Be aware of this change in communications with your regulator if you are an involved stakeholder. On April 3, the Ontario government announced a REVIEW ENVIRONMENTAL HEALTH AND SAFETY POLICIES temporary exemption of Ontario MinAND PROCEDURES istries from a regular 30-day public conWhile there are competing interests to sultation period so that it can expedite keep companies functional and opera- decision-making and implementation of tional, now is a good time to have policies measures to respond to the COVID-19 and procedures reviewed to determine if emergency. Many government agencies have stated any temporary changes are required as a result of COVID-19 operational reali- they will be posting a “frequently asked ties. In some companies, employees are questions” for the regulated community. now working remotely. Consider del- As the current situation continues to rapegating this review to someone who is idly change, our team is available to assist now working remotely, as opposed to at you across Canada for any of your envia facility. Policies and procedures are an ronmental legal needs. important part of operational concerns and are also important to potential due Janet Bobechko is a Senior Partner and Certified Specialist diligence defenses.

until the current state of emergency declaration expires or is cancelled. In Alberta, the Court of Queen’s Bench has adjourned all civil matters scheduled for hearings up to May 1. All filing deadlines under the Alberta Rules of Court are suspended until that time. At this time, the court will only hear emergency matters.

WHAT COMES NEXT? Companies should continue to consider the implications of changes to their operations if further government-ordered shutdowns are implemented and workforces and supply chains are further affected.

in Environmental Law at Norton Rose Fulbright Canada LLP. Email janet.bobechko@nortonrosefulbright.com For the most up-to-date articles on COVID-19, visit nortonrosefulbright.com/coronavirus

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April/May 2020 | 15

BIOSOLIDS MANAGEMENT

New fluid bed municipal Biosolids incinerator and dryer meet updated emission limits By Peter Burrowes, Bruce Bartel and Levent Takmaz

he Green Bay Wastewater Treatment Plant (WWTP) is owned and operated by NEW Water and is designed to treat 113 million litres of wastewater per day from surrounding communities. It uses fluid bed incineration to reduce the volume of digested biosolids generated during the wastewater treatment process. The facility went through a major solids handling upgrade. This included two anaerobic digesters, coupled with a combined heat and power (CHP) cogeneration system and a new cold wind-box fluid bed incineration system. This replaced the existing multiple hearth furnaces. A sludge dryer was installed upstream of the fluid bed incineration system, increasing the dryness of digested sludge in order to achieve autogenous combustion with no fossil fuel consumption.

INCINERATION BASICS AND AIR POLLUTION CONTROLS The reactor features a cold wind-box, refractory arch dome and teardrop shape freeboard. It is designed to burn 46 dry tonnes per day autogenously with “zero” fuel consumption. Sludge has a heat value of 5,833 kcal/ kg, based on volatile, 64.9% volatile and 39% total solids at reactor inlet. A sludge dryer is installed upstream of the fluid bed incinerator to increase sludge dryness from about 21% to 39%. This eliminates auxiliary fuel consumption during normal operation. A hot oil economizer is installed downstream from the reactor to produce 200°C oil. After this, a wet scrubber equipped with a quench section, cooling tray and a multiple venturi section is installed to remove particulate and acid gas from the flue gas. A wet electrostatic precipitator (WESP) is installed after the scrubber to polish clean flue gas before it enters the demister. Here, free water droplets are removed. 16 | April/May 2020

The NEW Water fluid bed reactor is designed to burn 46 dry tonnes of digested biosolids per day autogenously with “zero” fuel consumption.

The flue gas temperature is increased above the dew point through a hot oil heat exchanger installed after the demister. Clean flue gas from the hot oil heat exchanger is passed through a fixed carbon bed adsorber for mercury, dioxin and furan removal. Caustic is injected into the scrubber tray section to meet limits for hydrogen chloride (HCl) and sulphur dioxide (SO2). A caustic recirculation system is employed to minimize the caustic consumption during normal operation. A pH analyzer is installed on the return line of the caustic recirculation system to monitor the pH level to adjust the amount of caustic injection. Ammonia injection is part of the overall design for NOx removal. There are six ammonia injection guns installed on the reactor freeboard. In addition, there are three injection guns installed on the hot gas duct to inject ammonia at 19% con-

centration to meet the NOx emission limit. A low NOx preheat burner is used during cold start up. Ash slurry from the scrubber is discharged to an ash tank and then transferred by ash pumps to a lagoon. COMMISSIONING AND PERFORMANCE TESTING Table 1 shows the overall stack emission test results from the new incinerator. It meets the emission limits for a new incinerator, including mercury. Average mercury emissions during the twostack testing were 0.0002 mg/dscm. It also shows the dioxin and furan emissions for both units. The level of cadmium (Cd) emissions stayed below 0.00007 mg/dscm and 0.0002 mg/dscm during the first and second stack tests, respectively, being significantly lower than the emission limit of 0.0011 mg/dscm. Overall, dioxin and furan emissions continued overleaf…

Environmental Science & Engineering Magazine

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BIOSOLIDS MANAGEMENT

A sludge dryer was installed upstream of the fluid bed incineration system. Units (7% O2)

MACT

TEST RESULT (Oct 17 – 18, 2018)

TEST RESULT (May 1 – 2, 2019)

mg/dscm

0.0011

<0.00007

<0.0002

CDD/CDF TMB

ng/dscm

0.013

0.003

<0.0007

CDD/CDF TEQ

ng/dscm

0.0044

0.0026

<0.0019

ppmvd

1.2

0.37

HCl

ppmvd

0.24

<0.1

<0.07

mg/dscm

0.001

0.0002

<0.0002

NOx

ppmvd

12.8

mg/dscm

0.00062

0.00049

0.00053

mg/dscm

9.6

<0.6

SO2

ppmvd

5.3

0.1

3.4

Pollutant

Opacity

Table 1: NEW Water incinerator stack emission test results.

based on total mass basis stayed at 0.003 ng/dscm during the first stack testing. Dioxin and furan emissions were below 0.0007 ng/dscm during the second stack testing, meeting the requirement of 0.013 ng/dscm for both tests. Fixed carbon bed mercury removal system is the main reason for meeting the dioxin and furan emissions. Dioxin and furan emissions based on toxic equivalency basis stayed at 0.0026 18 | April/May 2020

ng/dscm during the first stack testing. Dioxin and furan emissions were below 0.0019 ng/dscm during the second stack testing, meeting the emission limit of 0.0044 ng/dscm during both stack tests. The new incinerator had an average of 1.2 ppmvd and 0.37 ppmvd carbon monoxide (CO) emissions during the first and second stack testing, respectively. This is significantly lower than the emission limit of 27 ppmvd. Low CO emis-

sions are the result of high combustion efficiency inside the fluid bed and having seven seconds of freeboard residence time inside the reactor. This resulted in complete combustion. Stack test results showed lower than 0.1 ppmvd hydrogen chloride (HCl) emissions during the first stack testing. Average HCl emissions were lower than 0.07 during the second stack testing. The incinerator met the limit on HCl emissions during both tests. Caustic injection system resulted in low HCl emissions. Average mercury (Hg) emissions in the stack were 0.0002 mg/dscm. The fixed carbon bed adsorber demonstrated great performance on removing mercury from the flue gas. Average oxides of nitrogen (NOx) emissions stayed at 12 ppmvd during the first stack testing, meeting the emission limit of 30 ppmvd. The incinerator was able to meet the NOx emissions limit without using the ammonia injection system during the first stack test. Currently, the facility is still meeting emission limits on NOx without using the ammonia injection system. Average NOx emissions during the second stack testing in May 2019 were 2.8 ppmvd. Visual observations showed zero opacity in line with emission limits. Average lead (Pb) emissions during the first stack testing were 0.00049 mg/dscm. This is lower than the emission limit of 0.00062 mg/dscm. Results of the second stack testing indicated that average lead emissions were 0.00053 mg/dscm. Particulate emissions (PM) stayed below 0.6 mg/dscm during both stack testing. Average sulphur dioxide (SO2) emissions were 0.1 and 3.4 ppmvd during the first and second stack testing, respectively. Peter Burrowes is with Jacobs Engineering. Email: peter.burrowes@jacobs.com. Bruce Bartel is with NEW Water. Email: bbartel@newwater.com. Levent Takmaz is with SUEZ WTS. Email: levent.takmaz@suez.com *References are available upon request.

Environmental Science & Engineering Magazine

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BIOSOLIDS MANAGEMENT

New technique could accelerate methane production from FOG and food waste By Brent Wittmeier

niversity of Alberta engineers say they have found a way to turn waste fat, oil and grease (FOG) into a steady supply of renewable energy. In a recent study, environmental engineering master’s student Bappi Chowdhury and his colleagues found that adding conductive materials to the waste products could potentially turn them into a reliable feedstock, allowing for a production rate of up to 70% more biomethane from a mixture of FOG and ordinary food waste in an anaerobic digester. Energy-rich, fat-filled wastes are extremely slow to break down, forming barriers that stymie microbial digestion or floating to the surface at waste treatment facilities, which collect biomethane in the process. These fats are composed of longer carbon chains that naturally degrade into natural gas and often wind up in landfills, where they slowly degrade

Environmental engineering master's student Bappi Chowdhury (left) and supervisor Bipro Dhar in the lab, with a "digester" they are developing that uses microbes to convert a mixture of food waste and fat, oil and grease into renewable biomethane. Photo: Sean Townsend

and are released into the atmosphere. This causes a problem because methane is roughly 30 times more potent than carbon dioxide as a heat-trapping gas. The study findings could have implications for municipalities struggling with clogged sewer lines, industrial agricultural facilities dealing with animal waste, or governments hoping to reduce climate impacts. “It could solve a lot of problems,” said Chowdhury, who was the lead author

of the study. “It’s sustainable, renewable energy, because as long as there are people, there will be food waste.” Conductive materials have long been used in waste and wastewater treatment, but only in the past decade have they been used to stimulate biomethane production. Granular activated carbon was the conductive material most effective in the new study, although it is better known for removing compounds that affect the smell and taste of treated water. But, according

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to Bipro Dhar, a University of Alberta assistant professor of environmental engineering, activated carbon can also function as a hub for microbes looking to dump or pick up electrons as part of biochemical processes. “It can change how microbes interact,” said Dhar, who supervised Chowdhury’s research. “It can significantly enhance how fast we can degrade those organics and produce biomethane.” The study also involved adding food waste to the mix to improve yields. Chowdhury found an optimal recipe of 70% food waste, which was sourced from waste from the HUB Mall on the university’s campus, and 30% fat, oil and grease from GHD Canada, an Ontario-based industry partner. He tested two conductive materials, granular activated carbon and magnetite, to see which worked better. The first conductive material reduced the time of decomposition from 20 – 25 days to just seven. “There’s a second reason that granular activated carbon works so well. Microbes that naturally break down lipids and fats grow right on the conductive materials. A wider range of microbes remain in the mix in the digester, ensuring decomposition is more efficient than it would be on its own. There was more enrichment of microorganisms,” Chowdhury said. “There are so many microbes attached to the surface, it creates more balance.” The new study is a potential game changer in treating organic waste, which makes up to 40% of municipal waste in Canada and 5% of global greenhouse gas emissions. Dhar lists a number of potential scenarios. If FOG could be readily and reliably digested, a city like Edmonton might accept agricultural waste or restaurant waste to enhance its organic waste treatment. A rural poultry farm might switch from transporting waste hundreds of kilometres and opt to generate power and heat on site. A rural area in a developing country could generate more electricity from waste. Because anaerobic digesters can work at a variety of scales without a significant retrofit, it is a solution that could potentially be implemented globally. Dhar sees another upside in the reduction of waste methane, a far more potent greenhouse gas that many overlook as a contributor to climate change. “The major problem with landfills is organic waste,” Dhar said. “Any kind of organics will eventually degrade and produce methane gas.” In 2015, EPCOR estimated that it spent $2 million cleaning 1,200 kilometres of Edmonton sewers, along with another $1.6 million inspecting lines throughout the city. While the city has “store it, don’t pour it” campaigns, the household grease that clogs sewer lines could one day be collected as a valuable resource. More work will first be needed, Dhar noted. That means looking for even better and cheaper conductive materials, economic feasibility studies and scaled-up pilot projects.

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April/May 2020 | 21

BIOSOLIDS MANAGEMENT

Geotextile system provides long-term biosolids management savings for small town By Kevin Bossy and Paul Saulnier

rior to 2014, the wastewater plant of North Rustico, Prince Edward Island, was disposing of as many as three truckloads of waste biosolids per week, at an annual cost of nearly $50,000. So, when the town of about 600 residents began planning to replace its aging wastewater plant, one of the top priorities was to implement a simple, economical and environmentally sustainable process for biosolids management. The result was the island’s first-ever system to incorporate geotextile bags and specially selected polymers to dewater municipal waste biosolids. Also, it produces composted, stabilized biosolids that are suitable for land application. This simple, low-energy approach eliminated the expense of daily biosolids hauling and enabled the North Rustico wastewater treatment facility to become self-sufficient for biosolids management. Dewatered solids are now composted on-site and either distributed on the property surrounding the plant, or taken by farmers to be used as a soil amendment. The success of this project was recognized in 2014 with the Excellence in Water Stewardship Award from the Council of the Federation, which is comprised of Canada’s provincial and territorial Premiers.

Biosolids produced at the plant have been approved by the PEI Department of Environment, Water and Climate Change for land application.

the community; simple process that does not add significantly to operator responsibilities; easily expandable to accommodate community growth; and operational flexibility. Although North Rustico only has about 600 permanent residents, this number can swell to as many as 10,000 during the STAKEHOLDERS WEIGH IN tourist season. Each process in the new “This was a truly collaborative effort,” treatment plant would have to be adaptsays Les Standen, chairman of the North able to the variable flow and wastewater Rustico water and sewer committee and characteristics that would be experienced deputy mayor. “We brought everyone throughout the year. together to design our new plant and ensure it met our operational, environ- GEOTEXTILE DEWATERING SYSTEM In 2014, North Rustico commissioned a mental and financial goals. Our operators played a key advisory role in addition to new sequential batch reactor (SBR) wasteconsulting engineers, equipment vendors water treatment plant designed to handle peak flows of 2,600 m3/day. The plant and our water and sewer committee.” Several factors were considered as the was also equipped with a new biosolids town evaluated biosolids management management system, supplied by Bishop options. Some of the most important fac- Water Technologies. It incorporates Geotors included: operational cost savings for tube geotextile dewatering containers, a

22 | April/May 2020

unique non-mechanical polymer mixing and activation system and a computerized control system that is integrated to the plant’s SCADA system. The process is simple. Waste biosolids from the plant are first pumped to a storage tank, which usually takes about six to 12 weeks to fill, depending on the time of year. Once full, the storage tank is aerated for several days to create a homogeneous biosolids mixture. Assistant operator, Lenny Blacquiere, was part of the original operations team for the new plant and was one of the first to begin using the system. He says that once aeration is complete, he performs a simple jar test to measure the solids concentration of the biosolids and calculate the polymer dose. “After the jar test is done, I just set the dose parameters on the control panel, open a few valves, start the pumps and the rest is pretty continued overleaf…

Environmental Science & Engineering Magazine

BIOSOLIDS MANAGEMENT

A VEPAS system monitors the flow rate and injects polymer directly into the biosolids line.

much automatic,” Blacquiere says. The dewatering system is equipped with a unique venturi emulsion polymer activation system (VEPAS), which mixes and activates polymer in a single step before injecting it directly into the biosolids flow line. Its venturi-based design also eliminates many of the components typically found in mechanical polymer systems, such as mixers and aging tanks. “Once we finish pumping out the biosolids storage tank, it only takes about an hour to completely disassemble, clean and reassemble the VEPAS,” Blacquiere says. By comparison, conventional polymer systems can take several hours or more to clean. Polymer is essential to accelerate and enhance the dewatering process and to prevent blockage of the microscopic pores in the woven polyethylene fibres of the geotextile bag. The VEPAS at North Rustico also incorporates PLC controls and sensors that measure biosolids flow rate and automatically adjust the polymer dose to maintain optimal dewater-

ing performance. Biosolids are pumped at a rate of about 250 L/min into one of four Geotube containers that are positioned on a large concrete lay-down area. Each container measures 17.4 m in length and 13.7 m in circumference. As the bag is filled and dewatering occurs, clear filtrate passes through the pores of the Geotube containers. It is then collected inside the laydown area and directed back to the plant headworks for additional treatment. DEWATERING CONTAINERS PROVIDE YEARS OF TROUBLE-FREE SERVICE Head operator, Preston Silliker, says the plant began operating with two dewatering bags, but an additional cell and two more containers were added in 2018. “With four dewatering containers, we can alternate their use to maximize the capacity of each bag and also provide plenty of time for the biosolids to dewater and compost. We can leave the bags on the pads for several seasons. As they dewater, volume decreases and more

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Environmental Science & Engineering Magazine

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Biosolids are pumped at a rate of about 250 L/min into one of four Geotube containers that are positioned on a large concrete lay-down area.

space becomes available for us to top them up again and again. Winter freeze also helps since they tend to lose a lot of water in the spring when they thaw.” As an example, in the prior season some Geotube containers were pumped to about 76 cm in height just before winter. In the spring, their height decreased by half, to about 38 cm, which enabled them to continue accepting biosolids throughout the following season. One additional Geotube container can be set up in a greenhouse during the winter months, enabling biosolids to be pumped and dewatered year-round. LONG-LASTING BENEFITS “Each dewatering container lasts for about three years before it’s full,” says Silliker. “When we open it up, the material inside is dry and light like peat and is odourless. We worked with the Department of Environment, Water and Climate Change to test that there are no harmful residuals in the biosolids and that they can be safely spread on farmland and our property.” “This system has provided many benefits to plant operation and our community,” Standen says. “Not only do we have on-site biosolids treatment, but also significant savings in labour and hauling fees. We’ve had this new plant for five years now and haven’t had to raise rates. This is in part because this new biosolids management system is helping save money for the community and keep rates low.”

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Kevin Bossy is with Bishop Water Technologies, Email: kevin@bishopwater.ca. Paul Saulnier is with ScotiaTech Fluid Services, who represent Bishop Water in Atlantic Canada. Email: scotiatech.paul@ns.sympatico.ca

www.esemag.com @ESEMAG

April/May 2020 | 25

WATER

PFAS are a component of many firefighting foams.

Treatment options for removing per- and polyfluoroalkyl substances from drinking water

er- and polyfluoroalkyl substances (PFAS), also commonly referred to as perfluorinated chemicals or PFCs, are a group of anthropogenic chemicals with past and current uses in industrial processes and consumer products. They are used in firefighting foams, coating for food packaging, ScotchGard , and Teflon , among other products. PFAS are highly resistant to chemical decomposition since the carbon-fluorine bond they contain is the strongest in organic chemistry. They are also soluble in water and can enter source waters through industrial releases, discharges from wastewater treatment plants, stormwater runoff, release of firefighting foams, and land application of contaminated biosolids. PFAS have been detected in surface, ground, tap and bottled waters, wastewater influents and effluents, industrial waste influents and effluents, and rivers, lakes and tributaries. The Water Research Foundation (WRF) has been performing research on compounds of emerging concern for over 50 years, helping utilities find treatment solutions for challenges like hexavalent

™

26 | April/May 2020

™

chromium, volatile organic compounds, endocrine disrupting compounds, and pharmaceuticals and personal care products. In 2015, it expanded this research to include the emerging issue of PFAS, with several projects currently ongoing and planned over the next five years to investigate occurrence, detection, and treatment. TREATMENT AND MITIGATION Because early research showed that conventional treatment strategies (i.e., coagulation, sedimentation, filtration, chlor[am]ination) do not effectively remove PFAS from drinking water, WRF has been leading the way on research into cutting-edge processes to treat and remove these substances. Published in 2015, Removal of Perfluoroalkyl Substances by PAC Adsorption and Anion Exchange assesses the effectiveness of innovative powdered activated carbon (PAC) adsorption and magnetic anion exchange processes for the removal of PFAS from drinking water sources. Apart from the more commonly studied perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate acid (PFOS), the

removal of eight additional perfluorinated chemicals (PFCs) that are frequently detected in water are also studied at environmentally relevant concentrations. Overall, the results of this research illustrate that PFAS are difficult to remove by superfine PAC adsorption and anion exchange. Anion exchange processes show greater promise for PFAS removal, if resins are regenerated in a manner that periodically restores the PFAS removal capacity. A possible alternative for PFAS removal could be a hybrid adsorption/anion exchange treatment approach, in which more strongly adsorbing PFAS are initially removed by activated carbon, and the more weakly adsorbing PFAS are removed subsequently by anion exchange. The hybrid approach may facilitate resin regeneration, which is more readily accomplished if only PFAS that interact more weakly with the resin need to be removed. While there are similarities and differences in toxicological effects among PFAS, in general, the longer-chain PFAS are more potent than the shorter-chain compounds. Granular activated carbon (GAC), superfine powdered activated carbon, and anion exchange (AIX) can remove many PFAS but are less effective at removing shorter chain PFAS, although science on this topic is constantly changing. Published in 2016, Treatment Mitigation Strategies for Poly– and Perfluorinated Chemicals evaluates the ability of a wide spectrum of full-scale water treatment techniques to remove PFAS from contaminated raw water or potable reuse sources. The project looks at 15 full-scale water treatment systems, including two potable reuse treatment systems, for attenuation of PFAS. These systems included a wide range of full-scale treatment techniques, including conventional and advanced technologies, such as ferric and alum coagulation, granular/micro-/ultrafiltration, aeration, oxidation, disinfection, GAC, AIX, reverse osmosis (RO), nanofiltration (NF), dissolved air flotation, and river bank filtration. A low-level liquid-chromatography tandem mass-spectrometry method was used to measure a suite of 23 PFAS in source water, finished drinking water, or potable reuse product water, and at various steps along the treatment train. continued overleaf…

Environmental Science & Engineering Magazine

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adsorbing PFAS are initially removed by activated carbon, and the more weakly adsorbing PFAS are removed WATER by anion exchange. The hybrid approach subsequently may facilitate resin regeneration, which is more readily

tion, aeration, oxidation, disinfection, GAC, anion exchange (AIX), reverse osmosis (RO), nanofiltration (NF), dissolved air flotation, and river bank filtration. A low-level liquidchromatography tandem mass-spectrometry method was

PFAS: EXPOSURE ROUTES

HISTORY OF PFAS PRODUCTION 1949: 3M begins producing PFOSbased compounds 1967: Approved for use in food packaging 2002: 3M phases out PFOS production 2008: 3M phases out PFOA production 2015: All manufacturers phase out PFOA production In addition, this study further evaluated two treatment technologies at benchscale, GAC and NF, for the removal of a suite of perfluoroalkyl carboxylic acids (PFCAs) and perfluoroalkane sulfonates (PFSAs). This study reinforces that full-scale conventional treatments, such as coagulation followed by physical separation processes, and chemical oxidation, aeration, and disinfection, are not effective in removing PFAS. NF/RO rejected almost all PFAS studied, but treatment should be further investigated and validated at pilot- and full-scale. RO is a costly treatment method, and disposal or treatment of the membrane concentrate stream is a consideration for both NF and RO.

Outdoor Uses PFAS Producing/ Using Factory

Indoor Uses HUMAN EXPOSURE Water Treatment Solid Waste

Urban/Rural Wastewater Treatment Stormwater

Water Supply Surface Water Ground Water

Courtesy WRF

likelihood of PFAS formation after ozonation of treated wastewaters; evaluates the factors responsible for the formation of these byproducts; and recommends potential mitigation strategies. Based on full- and pilot-scale system performance data and systematic benchFORMATION AND OCCURRENCE scale studies, some PFAS, including perBecause preventing the formation of fluoropentanoic acid, perfluorohexanoic PFAS before they can become part of our acid (PFHxA), PFOA, and perfluorobuwater systems is one of the most effec- tane sulfonic acid, were formed after ozotive mitigation strategies, WRF has also nation of secondary treated wastewaters. been exploring where and how these PFHxA was most frequently formed. substances are formed and what can be Depending on future regulatory determidone to offset the generation process. nations, these contaminants could be of Ozone treatment can mitigate human concern for potable reuse treatment sysand environmental impacts associated tems that employ ozone. with trace organic contaminants, makControl strategies, such as full nitrifiing it a promising treatment alternative cation during secondary biological treatin water reuse applications, particularly ment, optimized ozone dosing, or cerpotable reuse. However, the formation of tain post-treatment technologies can be ozone byproducts, including PFAS, could implemented to potentially mitigate the be a barrier to the widespread use of ozone. formation of these contaminants. In some The 2015 WRF report, Formation of instances, secondary biological treatment Nitrosamines and Perfluoroalkyl Acids resulted in increased PFAS concentrations. During Ozonation in Water Reuse Applications, evaluates PFAS occurrence, factors LIFT affecting formation, and potential mitigaThe Leaders Innovation Forum for tion strategies. The research explores the Technology (LIFT) helps move water 28 | April/May 2020

AQUATIC ECOSYSTEM/ FISH EXPOSURE

technology to the field quickly and efficiently. Recognizing that PFAS contamination is a challenge for more and more communities, in 2019, LIFT announced the launch of a PFAS Focus Group, which will investigate PFAS removal technologies and strategies from both a water quality and biosolids perspective. WHAT’S NEXT? In early 2018, WRF was awarded funding to conduct the research project Evaluation and Life Cycle Comparison of Ex-Situ Treatment Technologies for Poly- and Perfluoroalkyl Substances in Groundwater. This project will develop a framework for assessing treatment techniques from a life-cycle cost and assessment perspective, which will be structured based on input gathered during an expert workshop. This research will help fill knowledge gaps by evaluating traditional techniques and developing treatment technologies. In addition to creating the framework, the project team will develop a treatment testing protocol and conduct laboratory-scale studies to evaluate the performance of various technologies for PFAS removal under different treatment sce-

Environmental Science & Engineering Magazine

narios. The results will be used to develop an Excel-based decision support tool to help utilities and other practitioners select the most viable treatment technologies for different scenarios on a life-cycle cost and assessment basis by identifying advantages, disadvantages, limitations, and costs of the various technologies. Another ongoing project, Concept Development of Chemical Treatment Strategy for PFOS-Contaminated Water, will develop a practical high-efficiency chemical treatment strategy for PFOS. To decompose PFOS effectively, this research investigates advanced oxidation integrated with chemical reduction (AIR as a novel treatment strategy). The AIR strategy might have high potential to expedite the decomposition of PFOS via various chemical routes combining hydroxyl radical-oxidation, sulfate radical-oxidation, superoxide radical anion-reduction, and electrochemical defluorination. The strategy is implemented by using zerovalent iron (Fe, ZVI) nanoparticles conjugated with common oxidants

(FECO as a tactical system). If the AIR strategy and the FECO system work for PFOS in this study, it could work for other problematic short-chain PFCs, significantly contributing to development of effective chemical treatment options for water contaminated with many persistent organic chemicals. Funded in 2018, Investigation of Treatment Alternatives for Short-Chain PFAS will develop a guidance manual to aid water treatment professionals in selecting the most cost-effective and sustainable treatment options for short-chain PFAS removal. The guidance manual will consider the effects of background water matrices and uncertainties involved with scaling up from bench-scale performance data to field-scale design. In addition, a decision support tool will be created to aid water professionals in selecting effective treatment options for short-chain PFAS removal in their unique water matrices and appropriate bench-scale tests to compare sorbents, resins or membranes.

Because PFAS are used in a wide variety of consumer care products, which are typically washed down drains, they are being found in wastewater treatment plant influent and effluent. And now, municipal wastewater effluents and biosolids are being viewed as a potential source of PFAS in the aquatic environment. During wastewater treatment, polyfluoroalkyl compounds (often called precursors) can degrade into perfluoroalkyl compounds. However, due to their chemical nature, these compounds are not efficiently removed during conventional wastewater and sludge treatment processes. Thus, the release of treated effluent as well as the widespread land application of biosolids provides an opportunity for the re-release of PFAS into receiving environments. In 2019, WRF funded Occurrence of PFAS Compounds in Wastewater Treatment Plants to explore these implications. For more information, visit www.waterrf.org

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April/May 2020 | 29

WATER

A bank of five ORG/A-040-LS automatic self-cleaning filters.

Automatic self-cleaning filters allow Alberta county to stretch its potable water supply By Marcus Allhands

teady growth in population, industry and tourism has caused higher demands for potable water in Northern Sunrise County in Northern Alberta, exceeding the capacity of the two local water treatment plants. In 2004, the county decided to initiate a program to lower the demand on potable water for non-potable uses. One aspect of this program was to discourage the use of potable water by farmers for irrigation by providing them with a ready source of non-potable irrigation water. To this end, 150-micron manually cleaned strainer baskets were installed in two locations. Though not as clean as treated potable water, local producers supported the effort. The problem with the filtered water was that it was still not clean enough and using treated drinking water caused a suspected reaction between the chlorine in the water and the agricultural chemicals, with deposits plugging sprayer nozzles. To conserve water, irrigation systems in

30 | April/May 2020

use today have micro-spray emitters close to the ground that spray a fine mist of water onto crops. This method increases irrigation efficiency by directing most of the water onto the ground right around the plants to cover the root zone and minimize drift and evaporation losses. Because these micro-spray emitters have such a small orifice, the water must be free from all solid particles that could cause clogging. Some farmers may soon start using drip irrigation technology, which is more efficient than micro-spray emitters. However, it is even more dependent upon high water quality. If water provided to farmers by the county is not clean enough, they will simply go back to using potable water for irrigation purposes, which strains public water supplies. Only quality filtration equipment can remove both heavy solids such as sand and lighter organics like algae, rendering non-potable water usable for irrigation purposes. A better filtration system was needed and Brent Schapansky, county utilities coordinator, was called upon to lead the project.

THE SOLUTION Stormwater and spring runoff is collected in ponds and basins, called dugouts, throughout Northern Sunrise County. This water picks up sand, grit and windblown debris, making it unfit for modern water-conserving irrigation systems. Schapansky contacted ORIVAL Inc. for an automatic self-cleaning filtration solution. Subsequently, an ORG/A-040-LS automatic self-cleaning filter with a 50-micron weave-wire stainless steel screen was installed as a pilot filter to determine the feasibility of using this technology to treat the water from the dugouts to a high enough standard to prevent clogging of farmers’ irrigation systems. Farmers simply pull up to a dugout with their tanker trucks and fill up with water to haul back to their fields for irrigation. The filtration system sits between the pump and the truck, assuring high water quality for the most stringent irrigation system. Figure 1 shows the pilot filter installation. FILTER OPERATION Water passes into the filter body at the bottom (as show in Figure 2) and then through the 50-micron cylindrical screen element from the inside out. Suspended solids larger than 50 microns are retained on the screen surface and soon build up a layer called a filter cake. The openings between particles in this filter cake are smaller than 50 microns. This allows the filter cake to act as a filter medium, capturing smaller and smaller particles. When a differential pressure switch senses a sustained pressure drop of 7 psi across the filter, it signals the controller to initiate a rinse cycle. A rinse valve opens the internal rinse chamber to atmosphere, dropping the pressure in the chamber. Water wants to move from the high pressure-filtering chamber to the rinse chamber but can only do so by passing into nozzles on the dirt collector and out the hydraulic motor in the rinse chamber. This water movement causes the hydraulic motor to rotate the dirt collector. Nozzle openings are so close to the screen element that water rushes backwards through the screen (from clean side to dirty side) in a very small area at high velocity. This pulls the filter cake off the screen, into the nozzles, through the dirt collector, into the rinse chamber

Environmental Science & Engineering Magazine

and out the rinse valve to a convenient drain. A piston on top of the filter is normally pressurized by water pressure holding the dirt collector down to its lowest position. During the rinse cycle this pressure is bled off, allowing the dirt collector to be slowly pushed upward by pressure in the filter chamber. The combination of rotation and upward linear movement causes the nozzles to pass every square inch of screen area, assuring a clean screen. After about 12 seconds the cleaning cycle is complete and the rinse valve closes, the dirt collector stops rotating and the piston is re-pressurized to place the dirt collector back into its lower starting position. While all this is happening, the filter continues to supply clean filtered water downstream to the truck without interruption. Figure 1: ORIVAL ORG-040-LS pilot filter. RESULTS According to Schapansky, “water coming out of the ORIVAL filter tested at 1.1 NTU which is just over the Alberta drinking water standard by 0.1 NTU with no chemical treatment.” As a result of this pilot test, a second ORIVAL filter was purchased and set up as a fully automatic self-cleaning filtration system requiring no operator intervention whatsoever. The pilot unit will be incorporated into the local treated water reservoir building with a new submersible pump that has sufficient output to make the unit fully automatic as well. Supply at the pilot location is two dugouts formerly feeding the small drinking water plant. A heated building and large supply mean this site could remain open year-round for industrial and firefighting use. More ORIVAL automatic filters are to be purchased as the program expands. The county is considering a by-law that will require all agricultural water come from filtered dugouts.

Marcus Allhands, PhD, PE, is with ORIVAL Inc. For more information email: filters@orival.com or visit www.orival.com

Figure 2: ORIVAL ORG/A cutaway.

Figure 2. ORIVAL ORG/A Cutaway

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April/May 2020 | 31

WATER

City adopts preventative water loss program with acoustic leak detection technology By Alain Lalonde

ocated in southern Ontario at the confluence of the Grand and Speed Rivers, Cambridge is the second largest community within the fast-growing Region of Waterloo. With 98% of its water consumption drawn from groundwater, and 2% from surface water, the city operates and maintains 523 km of mains to adequately distribute water to a population of 129,920.

RECOGNIZING THE NEED FOR CONCLUSIVE DATA Like many communities, Cambridge grapples with increasing demands on its ageing, thin-walled cast iron distribution mains and copper services that were installed in the 1950s and 1960s. Further shackled by the shortfalls in sustainable funding, the city’s physical water loss, currently at 21.7%, is 7.7 percentage points above the national average. To reduce water loss to an acceptable level of 14%, the city is adopting a preventative maintenance and leak detection program, proactively finding and fixing leaks. Before going forth with this program, the city engaged several outside contractors to carry out leak detection surveys of its water distribution network on an annual basis. The drawbacks from this approach were the severe lack of clear and conclusive data to pinpoint exactly where a leak might be, and the limited ability to audit and track overall performance of the contractors. Another attempted solution was to use satellite technology to detect chlorinated water underground. This pilot study was not successful in Cambridge and was not instrumental in identifying leaks within the water distribution system. INNOVATE WITH PROVEN ADVANCED ACOUSTIC TECHNOLOGY The city’s effort to reduce water loss has been supported by several strategies 32 | April/May 2020

City of Cambridge’s field engineer opening a hydrant valve to charge the hydrant in preparation for leak noise correlation using Echologics LeakFinderST.

through the adoption of innovative technologies. Innovations related to repair techniques, proactive leak detection and a continued focus on asset management have led to significant reductions in water lost to date. One of the notable strategies is the use of acoustic leak detection technology to pinpoint leaks. The Echologics LeakFinderST is an advanced Windows-based leak noise correlator that is used by field engineers to conduct a non-invasive leak detection survey by placing two magnetic surface

sensors on valves or any contact point connected to selected sections of a water system. Once the sensors are in place, the correlator listens for variations of acoustic signals induced in the pipe by any means, for example, flowing water from fire hydrants, or physically tapping on appurtenances such as valves. Analysis of changes in the acoustic signals enables the team to pinpoint leaks and measure the effective wall thickness of pipes without breaking ground or disrupting service.

Environmental Science & Engineering Magazine

“From an operation standpoint, we’re finding leaks before they surface. These are underground quiet leaks, with no indication of low water pressure or poor water quality,” says Jessie Koczynasz, water technologist at the city of Cambridge. “This technology gives us the step ahead with its accurate near real-time data that allows us to locate and repair these leaks swiftly before a pipe burst. This really helps cast us in a positive light with our customers,” Koczynasz adds. Leak detection technicians deploy mobile “lift & shift” acoustic loggers to scan an area for leak noise overnight. This is an application that is commonly practiced. Locations identified with potential leak noise from the loggers are then field verified with the LeakFinderST to confirm the presence and exact location of leaks. “What is really advantageous about this technology is its ease of use. You don’t need someone with a technical background to operate this system. After just one day of training by Echologics’ field

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bridge’s water system can be observed over the past decade. Just over the past couple of years since the use of this new system, the city has surveyed approximately 25 km of water mains. This application has helped unearth more than 50 sizable active leaks from distribution mains and service lines. According to the city, savings of 5,500 litres of water per minute were realized in the reduction in water loss. Costs associated with emergency repairs and the intangible reputational risk were also more efficiently managed as a result. “I would advise other municipalities to City of Cambridge’s field engineer performing build a business plan to present the ecocorrelation data analysis on the Echologics nomic impacts of finding and repairing LeakFinderST software. non-surfacing leaks,” advises Koczynasz. “This can justify the initial investment engineers, and several weeks in the field, into a leak detection program. Engageour leak detection technicians were fully ment from all levels within your organiequipped to properly implement the sys- zation is important too.” tem,” Koczynasz adds. Alain Lalonde is Echologics Regional

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April/May 2020 | 33

STORMWATER

Helping utilities and municipalities manage stormwater and green infrastructure

recipitation is a basic part of the water cycle, filling streams and lakes and soaking into the ground to replenish our aquifers. Most moderate rainfall is readily absorbed by soil, which acts as a natural filter as water moves through the cycle. But, in heavy storms, too much of a good thing can be problematic, causing excess moisture to run off over-saturated ground and impervious surfaces. And, because we’ve engineered so much of our land with resistant surfaces, that runoff can be excessive. Without the benefit of natural filtration, stormwater flows directly to waterbodies, storm drains, and sewer systems, taking with it any debris, chemicals, bacteria, eroded soil, and other pollutants it picks up along the way. While new technologies and green infrastructure help reduce pollutant levels, many solutions are best equipped to handle frequent, low-intensity storms, rather than the sporadic, powerful storms experienced more recently. To compound the problem, population growth and rising water demand have increased dependence on local water sources, including groundwater recharge, raising more concern over potential contaminants. The Water Research Foundation (WRF) has a comprehensive body of research to help utilities and municipalities manage stormwater and green infrastructure to meet new and existing regulations, improve water quality, reduce flooding, enhance climate resiliency, and diversify their water supply. With more than 130 stormwater related projects, this science significantly increases the understanding of stormwater characteristics and maximizes its role as a beneficial resource. WRF research focuses on stormwater as part of an integrated approach to water management, helping to promote more adaptable, resilient water infrastructure and sources. Exploring the impact of runoff on water quality was among the first stormwater research WRF undertook, and it is an area committed to today. Studying the effects of bacteria, nutrients, cyanotoxins, 34 | April/May 2020

The Water Research Foundation has a comprehensive body of research to help utilities and municipalities manage stormwater and green infrastructure.

and invasive species, this research creates a better understanding of contaminants and provides innovative solutions to help stormwater managers monitor and treat them in order to meet regulations. WRF research has led the way in identifying microorganisms in stormwater and accurately measuring their true risk. The 2008 guidebook Development of a Protocol for Risk Assessment of Microorganisms in Separate Stormwater Systems identifies the waterborne pathogens that pose the greatest risk to human health and measures their concentrations in stormwater. It also outlines a program for collecting data to assess the risk from exposure. WRF has also been a pioneer in helping meet water quality standards, which are often impacted by stormwater. In the early 2000s, it published some of the water sector’s first guidance on developing total maximum daily loads (TMDLs), the required plans for restoring waterbodies to meet standards for various uses. Navigating the TMDL Process is a four-volume series, which helps remove the uncertainty involved with these plans, laying the groundwork for a process that is practical, reasonable, and scientifically defensible. The reports offer useful tools

and information on topics such as the science behind listing and delisting water on impairment lists, as well as approaches for quantifying and allocating pollutant loads. This was followed up by the 2010 release of Drinking Water Source Protection Through Effective Use of TMDL Processes, which is a guide that helps drinking water utilities understand and get involved in the TMDL process. BEST MANAGEMENT PRACTICES With limited available funding, stormwater managers can’t settle for ineffective solutions. Beginning in the 1980s, WRF was among the first organizations to provide research on identifying, designing, and implementing best management practices (BMPs) to counteract the negative effects of runoff, and ultimately reduce the demand on wastewater treatment systems. WRF research looks at everything from more effective practices to structural solutions and provides tools to calculate the true cost of projects so realistic numbers can be weighed against potential results. In 1996, WRF partnered with two other organizations to launch the International Stormwater BMP Database. Starting as continued overleaf…

Environmental Science & Engineering Magazine

MANHOLE

SIDE INLET

STORMWATER a hub for sharing stormwater practices, it has grown to include over 700 BMP studies. The open-access site now houses the world’s largest collection of field data on stormwater BMP performance, tools, and monitoring guidance. This makes it easy to see what is working for others and which practices would be the most effective at specific sites. Over the past two decades, the website has continued to evolve, adding areas for topics such as agriculture and stormwater quality and pulling in other relevant partners. Despite best efforts to keep runoff from entering waterways, contaminant levels can still run high, driving some stormwater managers to look toward stream restoration as a new type of BMP. As a result, WRF once again expanded the BMP Database, adding a module that

go well beyond just meeting stormwater goals, offering community perks like ponds, parks and rain gardens. WRF research helps lead the way in this area, providing science to improve practices, lower costs, and boost environmental and social benefits by using rainwater to cultivate livable communities. Because green infrastructure has become a successful piece of many stormwater programs, more utilities and municipalities are looking for ways to broaden the impact. WRF is working to expand the use and open the door for specifically targeted options like green infrastructure on privately owned land. Incentives for Green Infrastructure Implementation on Private Property provides the most comprehensive look at incentive programs to date, helping home in

accurately weigh the costs and benefits of alternative stormwater practices, including green infrastructure.

WATER SUPPLY DIVERSITY As the demand for water continues to rise, many drinking water facilities are exploring alternative water sources to meet this demand, and WRF research is helping to carve out stormwater’s role. Until now, large-scale direct potable reuse of stormwater has been largely nonexistent in the United States. WRF intends to change that through projects like Alternative Water Source Requirements for Conventional Drinking Water Treatment, which found that stormwater blended with surface water can potentially be treated with conventional drinking water processes under the right water quality conditions and with additional disinfection. In conjunction with this study, WRF released A·SWAT, the Alternative Source Water Assessment Tool, a program that Many drinking water facilities are exploring allows users to look at potential water alternative water sources to meet rising sources and estimate the quality of water that can be produced through treatdemand, and WRF research is helping to ment. It then ranks the suitability of those carve out stormwater’s role. sources for drinking. The tool also offers strategies to improve water that falls short of being ready for conventional treatment. Because getting started is often the hardest part of integrating stormwater into a balanced water portfolio, WRF covers stream restoration practice selec- on exercises that offer the most motiva- research is making it easier for utilities to tion and design, water quality crediting, tion for land owners to adopt practices take the first step. A recently released tool and performance evaluations. based on particular circumstances. It Drivers, Hindrances, Planning, and BeneThis was followed up by the releases covers everything from rebates to credit fits Quantification: Economic Pathways of Stream Restoration as a BMP: Credit- trading to redevelopment incentives. and Partners for Water Reuse and Storming Guidance and Crediting Water QualWRF is also tackling what is often water Harvesting helps utilities weigh the ity Benefits from Stream Restoration. The the first and most complex step in get- benefits from reuse, like stormwater, and two reports lay out a framework for ting a green infrastructure project off provides resources to jump start projects. measuring benefits of the top restoration the ground: calculating the full cost. It practices, highlighting those suitable for is collaborating with several universities EXTREME WEATHER water quality crediting, and help utilities and organizations to develop a publicly In recent decades many parts of the and municipalities learn how to apply accessible tool to compare life cycle costs world have seen an increase in extreme crediting guidance to implement stream and benefits of green and gray infra- weather, and often the water sector is restoration. structure, as well as hybrid solutions. at the forefront of the impacts. As wet The tool, known as the Communi- weather becomes more severe and floodGREEN INFRASTRUCTURE ty-enabled Lifecycle Analysis of Stormwa- ing more widespread, WRF is helping As the challenge of treating stormwater ter Infrastructure Costs Tool, or CLASIC, facilities successfully adapt and protect continues to grow, more communities will help tally the expenses associated infrastructure and services. are turning toward natural processes to with designing, operating, maintaining, Water/Wastewater Utilities and Extreme clean and filter runoff, moving beyond and replacing stormwater infrastruc- Climate and Weather Events consolidated traditional infrastructure and incorpo- ture, based on life cycle costs, the value of experiences from watersheds and river rating green, sustainable solutions. co-benefits, and performance. This infor- basins and looked at how the water secThe benefits of green infrastructure mation will help decision makers more tor, including stormwater utilities, made 36 | April/May 2020

Environmental Science & Engineering Magazine

decisions in response to extreme weather. The report highlights successful, and often concurrent, strategies, underscoring the need for long-term preparedness and emergency response planning that considers multiple risks. Because understanding the impacts of extreme weather can help facilities respond more effectively, WRF is taking steps to identify and characterize these effects. In 2010, it released Implications of Climate Change for Adaptation by Wastewater and Stormwater Agencies, offering one of the first overarching views of what climate change can mean for stormwater facilities, connecting global warming signs with operations and infrastructure impacts. This was followed up in 2014 by Water Quality Impacts of Extreme Weather-Related Events. Based on case studies, the research highlights the stress that severe events can put on water treatment and conveyance, from source to tap, and includes a tool to search studies based on water quality impact, type of weather, location, and water source.

LIFT The Leaders Innovation Forum for Technology (LIFT) helps move water technology to the field quickly and efficiently. Recognizing the potential for technology to considerably change the way stormwater is treated and used, LIFT launched the Stormwater and Green Infrastructure Focus Area. This serves as a hub for facilities and communities interested in sharing information on practices and technologies that improve the design, cost, performance, maintenance, and communication aspects of green infrastructure and stormwater BMPs.

implementing green infrastructure and to evaluate the economic, environmental, and social values. This will supplement other available tools, such as the CLASIC tool and BMP Database, to support a more integrated stormwater management approach. WRF research will also help stormwater managers understand mounting regulations, providing resources and tools to develop effective TMDLs as well as advancing innovative technologies to meet water quality goals. Green and gray infrastructure will play an important role in how stormwater is treated, and WRF will provide the science to identify WHAT’S NEXT? the best practices and how to successBecause lack of funding and aging fully integrate both approaches. A large infrastructure continue to be a challenge portion of this will be centered around for many stormwater programs, WRF a watershed-based planning approach, is expanding efforts to measure costs integrating stream restoration, flood mitiand manage assets. The ongoing proj- gation, and stormwater retrofits to cost-efect Framework and Tools for Quantify- fectively meet water quality goals. ing Green Infrastructure Co-Benefits and Linking with Triple Bottom Line Analysis For more information, visit is helping to quantify the benefits of www.waterrf.org

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April/May 2020 | 37

WASTEWATER

Removing CECs from cold water post-lagoon wastewater treatment systems By Tanner Devlin and Philip Wiebe

Canadian-made wastewater treatment innovation could be part of a long-term sustainable solution for the removal of contaminants of emerging concern (CECs) in extreme cold climates. “With increased pressure on water resources, the issue of pharmaceuticals, personal care products, and pesticides in wastewater continues to grow,” says Nexom’s Dr. Pouria Jabari. “CECs are increasingly being detected at low levels in surface water, and there is concern that these compounds are affecting aquatic life.” It was this growing concern that prom- pted Jabari to join with the University of Winnipeg and Red River College in Manitoba in evaluating the removal of these types of compounds, using the fully-aerated submerged gravel bed technology known as SAGR.

38 | April/May 2020

Long Plain First Nation’s lagoon-based wastewater treatment plant upon construction, April 2012. Courtesy Nexom

MCN

LPFN

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THE RISKS POSED BY CECS Contaminants of emerging concern refer to many different kinds of chemicals, including medicines, personal care or household cleaning products, lawn care and agricultural products, among others. These chemicals make it into water bodies and have a detrimental effect on fish and other aquatic species. They have also been shown to bioaccumulate up the food web, putting even non-aquatic species at risk when they eat contaminated fish. One strain of CEC is known as endocrine disruptors (EDC), which alter the normal functions of hormones, resulting in a variety of health effects. EDCs can alter hormone levels leading to reproductive effects in aquatic organisms. A substantial challenge related to CECs is determining what is safe in the long term. Evaluating these effects may require testing methodologies, not typically available, along with endpoints not previously evaluated using current guidelines. The effects of exposure to aquatic organisms during the early stages of life

Figure Percentage removal of detected CECat inLPFN SAGR LPFN and MCN. Figure 1: 1: Percentage removal of detected CEC in SAGR andatMCN.

may not be observed until adulthood. SETTING UP THE STUDY “Of the 32 known target CECs, only eight were detected in the SAGR influent on both sites,” say These chemicals may also have specific “For this study, we wanted to evaluJabari, adding that atenolol was detected only at MCN. Out of those eight, he says, testing of the modes of action that may affect only cer- ate the removal of CECs in one or more effluent showed the SAGR had(e.g., removed CECsunder at different levels, tain types of aquatic animals verte-the detected communities extreme coldranging winterfrom low high treatment. brates such as fish). conditions,” says Jabari, “Since the sub-

“We see different levels of treatment for different CECs, because of the speed that each chemical Science & Engineeringwas Magazine breaks down in water,” says Jabari. TheEnvironmental anti-seizure drug carbamazepine not well-removed b SAGR at either site, possibly due to its low biodegradation rate at low temperatures. By comparis

merged attached-growth reactor itself was initially created for cold-climate ammonia removal, it was important that the study was conducted during the cold season under the harshest conditions for biology for which the system is designed.” SAGR is a Canadian innovation now installed at more than 70 sites across North America. It consists of a fully aerated coarse gravel bed, in which wastewater from sewage lagoons flows horizontally through the porous media. The gravel bed is insulated at the surface and continuously aerated, allowing the system to grow and maintain sufficient nitrifying biomass even at near-freezing temperatures of <1°C. Two existing sites with SAGR treatment systems were selected for this study: Misipawistik Cree Nation (MCN) and Long Plain First Nation (LPFN). LPFN had installed their SAGR system in 2012 in order to reach assigned total ammonia nitrogen (TAN) limits as low as <1 mg/L. MCN followed suit for the same concerns in 2013. “We chose these two sites due to their relatively close proximity to the University, which allowed for ease of travel to the sites for everyone involved,” explains Jabari. Both sites are among the oldest SAGR installations at nearly 10 years old, but they are still successfully achieving their original purpose of ammonia removal, which was also important for the study. THE RESULTS For the purpose of the study, water samples were collected biweekly over the course of the three-month project (January to March 2019, inclusive) for a total of seven samples per site. They were then sent to an accredited lab for testing wastewater parameters (e.g., N, P, TSS, and BOD, E. coli), as well as to the University of Winnipeg to measure for CECs. “The contaminants that we looked at were diclofenac, naproxen, atenolol, carbamazepine, clarithromycin, metoprolol, sulfamethoxazole, sulfapyridine, and trimethoprim,” says Jabari, adding that testing samples were taken from raw sewage, as well as the SAGR influent and effluent. Of the 14 samples taken over the course of the study, laboratory testing showed both the TSS and BOD levels in SAGR influent were well below the 25 www.esemag.com @ESEMAG

mg/L assigned limits in both categories, for each site. This information was not included in the reporting for the study, as there was no deviation from expectation. Additionally, the results of ammonia and total coliform showed the SAGR could deliver effective nitrification and disinfection performance at water temperature of <1°C, which has been previously documented. What wasn’t previ-

ously documented was how well it could remove CECs. “Of the 32 known target CECs, only eight were detected in the SAGR influent on both sites,” says Jabari, adding that atenolol was detected only at MCN. Out of those eight, he says, testing of the effluent showed the SAGR had removed the detected CECs at different levels, ranging continued overleaf…

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WASTEWATER from low to high treatment. “We see different levels of treatment for different CECs, because of the speed that each chemical breaks down in water,” says Jabari. The anti-seizure drug carbamazepine was not well removed by the SAGR at either site, possibly due to its low biodegradation rate at low temperatures. By comparison, he adds, the antibiotic trimethoprim was removed at a rate of

75% at both sites. Atenolol, which is used various treatment technologies and their to treat high blood pressure and was only effectiveness against CECs from 14 diffound at MCN, had a removal rate of 80%. ferent countries and regions. Its authors Jabari postulates that the CECs are suggested nitrifying bacteria, which are mainly removed from wastewater via the responsible for the removal of ammonia bacterial activity in the SAGR. One 2014 in biological treatment, would positively study entitled “A review on the occur- affect the removal of CECs. rence of micropollutants in the aquatic The other potential mechanisms are environment and their fate and removal less likely, says Jabari. “The SAGR surduring wastewater treatment” compared face is covered with insulation, meaning there is no light available for direct photolysis. The SAGR has a long solid retention time and so almost complete solid digestion. This means that CECs that are physically adsorbed in the SAGR bed, if not broken down by biology, would be released back to the effluent.” WHAT DOES IT MEAN FOR THE FUTURE? Rural Canadian sites, including Dead Horse Creek, Manitoba, and Cambridge Bay, Nunavut, have been the focus of similar studies that have found CECs within their respective wastewater treatment systems. Jabari believes the ability of the SAGR to remove these compounds would be beneficial to many communities like these, having been tested at water temperature below 1°C. These are typical winter conditions for Canada’s lagoon-based wastewater treatment plants, particularly on the prairies and further north. Despite seeing success in that environment, the removal of CECs in biological treatment processes is also negatively affected by the cold. Cold weather means less bacterial activity. With that in mind, the removal of CECs in warmer climates, where the biodegradation would be greater due to increased bacterial activity, has yet to be investigated. “What we can say for now is that results have shown that a technology already in place at many small Canadian municipal plants removes CECs at moderate level while also providing designed treatment performance, even in the extreme cold,” concludes Jabari.

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Tanner Devlin and Philip Wiebe are with Nexom. For more information, email: pwiebe@nexom.com

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40 | April/May 2020

Environmental Science & Engineering Magazine

WATER this occurs, operators should allow extra time, as much as 10 minutes, to flush the cuttings and loosen the stuck bit. If this does not resolve the problem, thickening the mud with bentonite to assist in removing the cuttings may help.

Lone Star Drills’ water well rigs use a mud rotary system to pump drilling mud in and out of the borehole to flush out cuttings.

Water well drilling takes careful preparation and experience By Joe Haynes

rilling for clean, uncontaminated water can be challenging. From operating the rig to understanding how to address circulation loss or a caved-in borehole, there is a lot to consider. Having the answers to these common questions prior to the bit hitting the ground will help make for a smooth drilling operation and a positive experience. The effort put forth to drill a well doesn’t begin on site. Before purchasing or renting a rig, knowing the drilling conditions can prevent a number of problems from occurring. If drilling through sand, clay or gravel, a mechanical unit should be up to the task. For rock formations, hydraulic drills are the better choice. When drilling in hard rock, also be prepared with heavyweight drill pipe, tricone rock bits and possibly a DTH hammer. Also, simple as it sounds, bring a toolbox for taking care of minor repairs before they become more serious. It should include a pipe joint compound, grease gun, wrenches and miscellaneous nuts and bolts.

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In addition to having the right equipment, training and know-how are equally important. Review resources from the manufacturer, such as the operator’s manual, and check if the manufacturer offers training classes or can recommend third-party courses. Also, see if there are step-by-step online videos to walk new drillers through setup and drill operation. Even with the right tools and training, however, operators can only fully anticipate what will happen above ground. Once a drill is 50, 100 or 400 feet down, unforeseen problems can surface. Here are a few of the more common troubleshooting questions that arise when well drilling operators are out in the field. WHY DOES THE BIT KEEP GETTING STUCK? While drilling, the drill bit may get stuck from time to time. In most cases, this happens as operators are drilling through sand or gravel. When the operator stops circulation to add the next section of drill pipe, the cuttings settle around the bit. If

WHY DID THE MUD PUMP SWIVEL WEAR OUT? Silica sand and cuttings in the drilling mud are the main cause of swivel wear due to their abrasiveness. A proper mud pit design will help alleviate the problem. Most water well rigs require a two-pit mud rotary system with a mud pump circulating the drilling mud. The mud is pumped from the suction pit to the bit, then back up, flushing out the cuttings with it. At the surface, it is pumped to the settling pit where abrasive silica and cuttings settle out before the mud gets to the suction pit. It is important to use two pits or these materials will not sufficiently settle out and will then run through the pump, causing wear. It also helps to include at least one 90-degree turn in the mud stream so the flow does not travel straight through the pit system. WHY DID THE WATER LEVEL IN THE PITS SUDDENLY DROP? If the water level in the pits drops quickly, the drill most likely encountered a porous formation where the mud is seeping from the borehole into openings in the rock. Drillers can combat this by adding a thick bentonite mixture to the suction pit and continue circulating the drilling mud. If this does not solve the problem, add materials such as chopped straw to the mud to help clog the porous rock. If circulation still does not resume, it is best to halt drilling. THE HOLE CAVED IN, NOW WHAT? If the borehole caves in, try to work the bit loose. Sometimes it is possible to dislodge the bit and salvage the project. However, in the worst-case scenario, the bit and some of the pipe will have to be left in the ground and the well abandoned. To prevent the borehole from caving in, and equipment being lost in a collapsed hole, always remove the pipe continued overleaf…

April/May 2020 | 41

WATER dence that points to a successful well. Regardless, it is important to know what to look for as the drill reaches the point where it should be encountering water. The answer is in the drilling mud. Always monitor and keep a log of the drill cuttings in the mud as it exits the borehole. If the cuttings change to a fine or coarse sand or gravel, the bit has likely drilled through water-bearing strata. Another indicator is if the mud dilutes and the temperature drops. This is a sure sign that the mud is mixing with groundwater. The only way to be certain, though, is to develop a well and test the yield. WHY DID THE CASING HANG UP AS I WAS INSTALLING IT? Mixing bentonite can be done by putting the suction and discharge hoses of the mud pump into the This happens for different reasons barrel and running it while slowly adding the powder. depending on the soil. If this happens while drilling in clay, the ground is likely swelling and closing the hole in the time during drilling breaks, even if it is a quick overnight, the pipe must be removed. between removing the drill pipe and lunch. If removing the pipe is not practiinserting the casing. The best solution is cal for some reason, simply raise the bit WHAT IF I DON’T HIT WATER to pull the casing and ream the hole to up about 5 to 10 feet and leave the mud AS SOON AS EXPECTED? pump running to maintain circulation. If This is only a problem if the drill open it. Sometimes, it is possible to force a break will be long, or operation is halted reaches max depth and there is no evi- the casing down; however, this might make it impossible to get the gravel pack around the screen. Another option is to use mud additives that mitigate the problem by preventing the clay from hydrating.

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AM I DONE YET? For the well to last and provide clean running water for years to come, it must be sealed off from surface water to prevent contamination. For the seal to be effective, the borehole diameter should be at least two inches greater than the casing diameter. The seal should reach the first impermeable sediment layer or, if that is not practical, extend as deep as possible. For sealing, neat cement can be mixed with water to create a grout or slurry and be poured or pumped between the casing and borehole wall. To prevent water from collecting at the top, create a small berm at the surface and fill it with the same mixture. After the well is sealed, wait at least 24 hours before installing a water pump. Joe Haynes is with Lone Star Drills. Email: sales@littlebeaver.com or visit www.lonestardrills.com

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REINVENTING THE CHEMICAL DOSING SYSTEM The DICE Dosing Module, by Meunier Technologies, integrates all the necessary discharge components required for a typical chemical dosing system. The block type design allows for a rigid, compact and reliable product, and the significantly reduced number of connections greatly decreases leakage potential. The module allows for better precision and protection in the dosing system, and also features great quality due to its machined fabrication. The Dosing Module overcomes the many fundamental problems of the current piping system design: • Poor quality of the piping connections; • Many potential leakage points; and • Excessive vibration caused by the pump pulsation – which leads to mechanical fatigue on connections and components. Other features include: • Integrated: ° Ball valves for outlet, calibration column, and drainage; ° Auxiliary ports: pulsation dampener, washing port, transport/dilution water and secondary pumps; ° Adjustable back pressure valve; ° Adjustable pressure relief valve; ° Pressure gauge with isolator; and ° Standard design that fits all your essential needs. • Extensive reliability and durability; • No threaded or glued connections; • Extremely compact design resulting in minimal footprint; • With only 3 supporting bolts and 4 connections, the module can easily be installed on new and existing systems (retrofit); • Possibility of having only 1 Dosing module for 3 pumps (1 injection point, 3 pumps); and • Capability of calibrating the pump with the correct suction head and discharge pressure.

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WASTEWATER COLLECTION

How to reduce the risk of I/I in new sanitary sewers from the private side By Barbara Robinson

he issue of inflow and infiltration (I/I) in new construction has been on the radar screen of engineers in Canada for some time. They have known for a long time that 50–60% of I/I in existing systems originates on the private side of the sewer system. Until now, however, we’ve lacked the understanding of the underlying issues that would allow reducing the risk of I/I in new construction. With the increased intensity and frequency of storms associated with climate change, it is essential that we reduce the risk of private side I/I when we build private side sewers. A recent publication, “Manual of Best Practices to Reduce Risk of Inflow and Infiltration in Private Side New Construction of Sanitary Sewers” provides practical, actionable solutions for building officials (and development engineering departments) to immediately implement strategies to reduce this I/I risk. The detailed research in this report was undertaken on the Ontario Building Code (OBC). However, issues discussed concerning specific Code references

It is essential that we reduce the risk of private side I/I when we build private side sewers.

stakeholders across Ontario and Canada, including municipal building and engineering staff, consultants, regulators, contractors, developers, drain layBACKGROUND AND METHODOLOGY This work is the result of five years ers, plumbers and other related groups. of study of the factors contributing to Stakeholders helped to identify gaps in I/I on the private side in new construc- guidelines, standards and codes, contion. The strategies presented are based struction practice, inspection and testing, on wide consultation with hundreds of certification, jurisdiction, education and related to I/I appear to be the same as in the National Plumbing Code of Canada.

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process, which contribute directly to the issue of excess I/I in new construction. Consultation has included: formal surveys, training on the OBC, ongoing discussions with both a building officials stakeholder group and a municipal engineering staff stakeholder group (both developed for this work), direct questions on the Code and its interpretation posed to the building officials stakeholder group. The work was also informed by the development of the CSA Z800 “Guidelines for Basement Flood Protection and Risk Reduction (2018)” and “Reducing the Risk of Inflow and Infiltration (I/I) in New Sewer Construction: A National Foundational Document (Standards Council of Canada, 2019)” and the direct engineering experience of myself. This work is essentially an engineering assessment of the factors contributing to I/I on the private side, and recommendations to reduce this risk. In order to implement many of these recommendations, building departments and engineering development departments will

Pipe Haunching Zone Flexible PVC Pipe

Haunching supports the pipe so it does not deflect horizontally (5 to 7.5% maximum allowed)

Springline of Pipe

Obvert of Pipe

Haunching Bedding

Figure 1.

need to work together.

different to what occurs on the public side. Construction of sewers on the priTHE ONTARIO BUILDING CODE (OBC) vate side is not subject to full time inspecIt is important for engineers to under- tion as it is on the public side. Building stand that application of the OBC, and its inspectors only attend site during Preassociated inspections, is fundamentally continued overleaf…

■ ■ ■ ■

■

www.esemag.com @ESEMAG

April/May 2020 | 45

WASTEWATER COLLECTION scribed Notices (e.g., at specific milestones in the construction). The Prescribed Notice that governs the Sanitary Building Sewers (SBS) requires that “the person to whom the Building Permit is issued shall notify the chief building official (CBO) of readiness for inspection and testing of building sewers and building drains” (paraphrased from OBC). This means that the building inspector only attends site to review the SBS when they are specifically contacted to undertake this inspection. This review takes place when the pipe is already laid and jointed (though not buried). Building departments are permitted to review only a fraction of the SBS in a subdivision (e.g., 10%) as a representative sample of all work on site. In addition, a developer does not usually install all the SBSs at once, but rather a few at a time. This requires the building inspector to make multiple trips to the site. This can be overwhelming for building departments, particularly if a lot of development is taking place at once. Necessarily, some inspections may get missed. Finally, building inspectors perform “inspection” per the OBC, but do not guarantee the work (similar to engineering inspectors: engineers review, but cannot be responsible for, construction, per Professional Engineers of Ontario). The only party who can be responsible for the proper and adequate installation of the SBS is the contractor installing it, who works for the developer. It is the developer who has a contractual relationship with the municipality, and he is ultimately responsible for ensuring that leak-free infrastructure is delivered.

Item

Number

11.

F112

To provide adequate treatment of sanitary sewage and effluent.

F113

To minimize the risk of injury as a result of contact with sanitary sewage or partially treated effluent.

F132

To limit excessive demand on the infrastructure.

F133

To limit excessive peak demand on the infrastructure.

13.

Function

Table 1: Functional Statements from the OBC.

of which state that they must be installed per CAN/CSA 182.11, which covers the design, installation, inspection, testing and acceptance of PVC pipe. Manufacturer’s literature explicitly recommends installation to these standards. Plastic pipe must be installed with flexible pipe principles that recognize that performance relies on proper bedding, haunching (embedment), backfill and compaction. Unlike concrete pipe (which has its own structural integrity, without the support of soils), PVC pipe relies especially on the embedment of the side soils (haunching) to keep it round against compression by the weight of overlying soil. Figure 1 shows the haunching zone which is essential for the performance of PVC pipe, and the potential deflection that occurs if haunching is not adequately provided and compacted. Engineers will already be familiar with these requirements, because they are specified in Ontario Provincial Standard Specifications (OPSS) and Ontario Provincial Standard Drawings (OPSD) for plastic pipe and widely used in Ontario and the rest of Canada. The OBC, while referencPRIMARY FINDING ing the relevant standards, includes only The most significant finding of this two sentences about the installation of research is that PVC pipe on the pri- the SBS, which are vague and inadequate. vate side is not currently being installed Specifically: according to existing CSA and ASTM –“Nominally horizontal piping that is standards, referenced in the OBC. These underground shall be supported on a base standards, which fall under the National that is firm and continuous under the Standard of Canada B1800-18, Thermo- whole of the pipe.” OBC 2018 plastic Nonpressure Piping Compendium, –“Where piping is installed underground, specify the requirements for installation the backfill shall be carefully placed and of the SBS, known in engineering as the tamped to a height of 300 mm over the top private side lateral. of the pipe and shall be free of stones, boulThese standards are the same as those ders, cinders and frozen earth.” OBC 2018 used on the public side sewer system, It should be noted that the 2018 OBC that is CAN/CSA 182.1 and 182.2, both references 426 external standards, many

46 | April/May 2020

of which need to be purchased. Building inspectors have a complex job that requires that they inspect for many issues and cannot possibly be familiar with (nor would they necessarily have access to) all the underlying standards that make up the Code. Since building inspectors have widely reported little or no understanding of I/I, its risks and impacts, they have not generally been looking for risk factors for I/I when inspecting the SBS. It has been recommended that the OBC include the specific requirements from the standards, right in the Code, to assist building inspectors in performing their work. Furthermore, CAN/CSA 182.11 requires that testing be performed after the pipe is buried. Currently, the OBC calls for leak testing prior to burial, which cannot detect joints that shift or separate during backfill operations. This is not in alignment with the governing standards and needs to be examined by Code officials. The OBC requires that air or water tests of the SBS be held for fifteen minutes with zero leakage. For most contractors, this would represent a substantial slowdown in production, and they are very reluctant to perform it. This leak testing is not currently being performed by the vast majority of building departments in Ontario. And finally, contractors have started to use clear stone as pipe bedding. While it is more expensive to supply, the labour costs are lower as it does not compact. However, clear stone is not explicitly permitted, and is not recommended because it acts like a French Drain. This allows water to travel along the trench bedding to the next available entry point to the sewer. Use of clear stone increases the

Environmental Science & Engineering Magazine

risk of I/I in sewer pipe systems and is not used on the public side. ADDITIONAL FINDINGS In addition to improving how we install PVC pipe on the private side, a number of other important factors have been identified as contributing to I/I risk on the private side. The use of solvent welded pipe systems on the private side does not appear to have been approved by any of the standards agencies. All citations and testing in the background technical specifications refers to gasketed pipe, so it is unclear that solvent welded pipe is suitable for underground installation. Furthermore, a two-step solvent weld system, whereby the solvent dissolves the PVC slightly and the cement then bonds it, is recommended. It is absolutely required in cold weather applications. Since the building inspector is not on-site during assembly of this pipe, the risk of poorly constructed joints is high. Initial set times for solvent weld joints range from one to twelve hours, depending on temperature, before the joint can be carefully handled. Therefore, using a solvent weld joint represents a significant risk of joint failure in the SBS. The OBC still contains provisions that permit the discharge of foundation drains and storm sewage to the sanitary sewer. These should be removed from the Code to align with modern design and sanitary sewer use bylaws. The inspection of the SBS to the sanitary sewer lateral at property line is implied in the Prescribed Notices, but not explicitly identified. Given that this location is a common source of I/I in older systems, it is recommended that this inspection be made more explicit to assist building inspectors in prioritizing this inspection. Currently, many building departments in Ontario are not inspecting storm infrastructure on the private side. Storm drainage in new construction is often hung from the side of the foundation wall prior to backfill. This means there is a risk that inadequately installed storm sewers could leak down the basement wall and get into the sanitary sewer (or cause the sump pump to cycle). This inspection is required in the OBC, so it is recommended that building departments undertake it. www.esemag.com @ESEMAG

Another issue of concern identified in haunched and installed without clear this work is the installation of backwater stone. Although the material costs for valves (BWV) on the sanitary building this Alternative Solution will increase, it drain. Standard backwater valves used will be offset by the time saved in holdin Canada require a 2% slope across the ing solvent weld joints for the required amount of time and set up and perforvalve to function adequately. However, both the sanitary building mance of the leak test. Ultimately, it drain (pipe under the concrete floor) and will cost less for contractors to use this the sanitary building sewer, are currently Alternative Solution than to install the only required to be laid at 1%. If BWVs SBS as explicitly required in the OBC. are to be installed, the slopes on the upstream and downstream pipes need HOW CAN DEVELOPMENT to be increased to 2%. Failure to adjust ENGINEERING DEPARTMENTS HELP? Reducing the risk of I/I in private these slopes increases the risk that the BWV will become hung up with solids side sewers can be achieved immediand will not work when flooding occurs. ately, if the will exists within a municipality. It will, however, require that building departments and development RECOMMENDATIONS The recommended best practice to engineering departments work together, immediately reduce the risk of I/I in the which is essential to reduce I/I risk. Development engineering departments SBS uses the power of the Building Code itself. Division A of the Code outlines typically negotiate the terms of the subdi-

If developers could be advised as soon as they approach a municipality that they will be required to meet the OBC explicitly, or use the suggested Alternative Solution, it would save headaches for building inspectors.

Objectives and Functional Statements which lay the groundwork for what the Code is trying to achieve. The Functional Statements that are of primary interest in reducing I/I risk relate to health and safety and demand on the infrastructure, and are summarized in Table 1. Based on the Building Code Act, the building department cannot ask for requirements that are more stringent than the building code itself. Division B of the OBC contains “Acceptable Solutions”, which are sample ways in which the objectives can be achieved for each construction item. The CBO has the authority to accept an Alternative Solution provided that it achieves the same level of performance called for in the Functional Statements. It is recommended that building departments offer the Alternative Solution of installing gasketed, SDR28 pipe that is

vision (or site plan) agreement, and outline requirements in a development manual or equivalent. If developers could be advised as soon as they approach a municipality that they will be required to meet the OBC explicitly, or use the suggested Alternative Solution, it would save headaches for building inspectors. In municipalities with significant capacity issues, or under a Ministry of the Environment, Conservation and Parks order to reduce I/I, this approach will be invaluable. The time to reduce the risk of I/I from the private side is now. We have the information and tools available to make these changes immediately. Barbara Robinson is with Norton Engineering Inc. Email: nortonengineeringinc@gmail.com or visit www.nortonengineeringinc.ca April/May 2020 | 47

GUEST COMMENT effects that may be greater than the sum of the effects of the individual chemicals.

It is wise to monitor for PFAS in waste management sites.

Canada needs more provincial regulations for per- and polyfluoroalkylated substances By Francois Lauzon

er- and polyfluoroalkylated substances (PFAS) are all around us, in many different places. These persistent contaminants can be found in microwave popcorn bags, pizza boxes, cosmetics, water-resistant clothing, firefighting foams, drinking water, paints and cleaning products, to name a few. But these man-made chemicals, which have been used since the 1940s, can have negative health consequences for humans. Thankfully, many jurisdictions around the world are setting regulations and standards for specific PFAS and are taking steps to assess their potential for human exposure. But, aside from British Columbia, we haven’t seen any guidelines from Canadian provinces on PFAS. Here’s why I think they are needed. These chemicals find their way into the environment and our drinking water supplies from industrial discharges, wastewater treatment plant aqueous effluents, biosolids land applications, and through long 48 | April/May 2020

range air dispersion of PFAS attached to fine water droplets. It has been 19 years since 3M announced that they would be voluntarily phasing out perfluorooctane sulfonate (PFOS), a PFAS and a key component of Scotchgard. Since then, other companies and organizations have also phased out many PFAS, thanks to government regulations restricting their manufacturing, import and use in many products. However, there is a lack of regulations on PFAS by Canadian provinces, either for their contaminated sites programs, or in the context of hazardous waste management or the wastewater industry. This regulatory inertia is mainly caused by the uncertainty about PFAS toxicity for many of the chemicals in the family, including their potential for synergistic effects on human toxicity. We have very limited understanding of the effect caused by the exposure to two or more PFAS at one time, resulting in health

WHAT ARE OTHER COUNTRIES DOING? The United Nations Environmental Program (UNEP) has published technical guidelines dealing with the sound management of wastes impacted by persistent organic pollutants (POPs). These guidelines include PFOS-containing wastes and require that they are disposed of in such a way that the POP content is destroyed, irreversibly transformed, or otherwise disposed of in an environmentally sound manner. According to the UNEP guidelines, wastes containing PFOS and its related substances should be minimized through isolation and source separation to prevent contamination of other waste streams. Ultimately, the guidelines say monitoring programs should be implemented in facilities that manage PFOS wastes. In the U.S., several states have issued, or proposed, low part per trillion (ppt) drinking water standards or groundwater cleanup goals. In April 2019, the United States Environmental Protection Agency published “Draft Interim Recommendations to Address Groundwater Contaminated with PFOA and PFOS” for public comment. Several states have taken actions to propose and implement their own PFAS remediation criteria. However, there is no state to state consistency. Australia is a leader in addressing PFAS. In 2018, an Intergovernmental Agreement on a National Framework for Responding to PFAS Contamination (the IGA) came into effect to support collaboration and cooperation to respond to PFAS contamination. Under the IGA, Australians have adopted a PFAS contamination response protocol, applied a national environmental management plan, and implemented guidelines to provide advice to government agencies involved in responding to PFAS contamination. A PFAS taskforce, established in 2016, coordinates these initiatives. Dealing with PFAS contamination has become a national priority. However, as noted in the Interstate Technology Regulatory Council (ITRC)’s History and Use of PFAS factsheet, the continued overleaf…

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GUEST COMMENT reported increased production of perfluorooctanoic acid (PFOA), considered another high-profile PFAS, and related PFAS in China, India and Russia, have potentially offset global reduction. The persistence of PFAS chemicals has generated a sustained scientific and political challenge to be resolved, and it continues to be an issue in many jurisdictions. So, what is Canada’s position on PFAS? WHAT CANADA’S FEDERAL GOVERNMENT IS DOING On a federal level, Canada took steps to deal with PFAS contaminants, notably long-chain perfluorocarboxylic acids (PFCAs), PFOS, and PFOA in the environment, beginning in 2006. At that point, the federal government concluded that PFOS, its salts, and certain other compounds could be entering the environment under conditions that could have an immediate or long-term harmful effect on the environment or its biological diversity. Human health assessment concluded that the 2006 levels of PFOS

50 | April/May 2020

exposure were below levels that might affect human health. By 2012, those chemicals were included in Canada’s Prohibition of Certain Toxic Chemicals regulations, which prohibit the manufacture, use, sale, offer for sale, or import of certain toxic substances, as well as products containing these substances. In 2018, Health Canada introduced drinking water screening values for PFOS, PFOA, and seven other PFAS. Health Canada further published soil screening values as well as drinking water quality guidelines in 2019. Values are regularly amended as new information is published in scientific literature. Other federal initiatives include the publication of a federal environmental quality guideline for PFOS in 2018 by Environment and Climate Change Canada (ECCC). Also, in that year, Canada’s Federal Contaminated Sites Action Plan published interim advice on waste removal approaches. ECCC is expecting the development of new regulatory amendments to the Environmental Protection Act’s Toxic

Substances List, targeted for publication later this year. Canada’s approach differs from the Australian model in that it lacks a centralized federal policy. In the absence of a centralized Canadian federal leadership champion, the PFAS issue will continue to be dealt with in a piecemeal approach, driven mainly by the evolving understanding of human and ecological risks across the country. The existing federal guidelines need to be partnered with provincial regulatory guidance. Without this, there simply will be no drivers to take any action for monitoring, assessing and remediating these chemicals. WHAT THE PROVINCES SHOULD DO Provincial governments are struggling with the deep uncertainties that continue to surround the management of PFAS in the environment. This is particularly true of the uncertainties related to our understanding of their toxicity, both to humans and to the environment, and their potential presence in drinking water, or in a

Environmental Science & Engineering Magazine

wide range of effluent streams, using existing monitoring guidelines. Provinces acknowledge the issue, mainly for PFOS and PFOA, and the potential presence of these contaminants in our wastewater treatment plant (WWTP) effluents and in terms of their relative toxicology. But, in the absence of hard data, sustainable cost-effective treatment technologies, and the potential for ambient levels found in the environment from multiple potential sources, provinces have not proposed any guidelines or standards beyond those proposed by the federal government. Aside from British Columbia, no provinces have released provincial standards. BC recently added PFOS to its water and soil schedules in the Stage 10 (Omnibus) amendments to the Contaminated Sites Regulation (CSR) under the BC Environmental Management Act. Ontario is working on a groundwater quality action level, but hasn’t officially released it. Considering the environmental and human health challenges created by

these chemicals, provinces need to start proposing standards for those PFAS for which we have a baseline of reliable information related to their environmental fate, transport and toxicity. This should include environmental standards for soils and groundwater (especially where potable water sources are of concern), standards for waste management and waste disposal, and standards for effluent monitoring from various sources such as WWTPs and landfills. Canadian provinces have suffered from the inertia of “paralysis by analysis”. Over analyzing has devolved into inaction. At a minimum, there is a social and ethical responsibility to protect human health by understanding whether PFAS are in our water supplies, and by understanding if we are allowing them to enter the environment through various effluents. This should be a priority for our provincial governments to focus on, while science tries to catch up.

MOVING FORWARD The good news is that people are paying attention to PFAS. The bad news is that it will take years before we resolve the issues surrounding them. Are the guidelines we’ve seen so far overly protective, or are the potential synergistic effects of exposure to a multitude of PFAS that are yet to be understood worse than what we think? At the moment, there are more questions and challenges than answers. It is time for the scientific community to work under federal and provincial leadership, with proper funding, and in collaboration with the international community, to come up with sustainable solutions that are based on sound risk management and not risk aversion. Francois Lauzon, Vice President, Environmental Services, Stantec. Email: francois.lauzon@stantec.com

I N S T R U M E N TAT I O N F O R W AT E R I N D U S T RY

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April/May 2020 | 51

WASTEWATER material on the heat exchanger surface. As with struvite, keeping water temperatures below 65°C will help prevent vivianite formation, as will carefully controlling the chemicals added to the sludge stream, although this is usually determined by other factors. Cleaning is very difficult, often relying on the use of hydrochloric acid solutions, which may not be compatible with the materials used in heat exchanger and system construction.

Fouling deposits can occur on the tube- and shell-sides of the heat exchanger depending on the materials being handled.

How to prevent the many types of heat exchanger fouling By Matt Hale

hen handling difficult materials, such as sewage sludge or corrosive chemicals, heat exchangers can be particularly susceptible to chemical, biological, sedimentation or corrosion fouling. In all cases, prevention is better than cure, but as each of these different types of fouling is caused by a different combination of chemical and physical reactions, prevention will take different forms. CHEMICAL FOULING Limescale is the most familiar chemical fouling agent, as for many of us it builds up in our kettles and pipework. In industrial applications, scaling is particularly problematic where cooling water has a high mineral content. Prevention takes the form of chemical dosing of the water, such as using salt or acid for “hard” water. Chemical agents are also required for cleaning or removal. Struvite (magnesium ammonium phosphate) is a phosphate mineral that often 52 | April/May 2020

precipitates in urine and can form kidney stones. It can be a particular problem in wastewater treatment plants, especially in systems that include anaerobic digestion as this releases ammonium and phosphate. Struvite forms a hard scale on many internal surfaces, including pipes and heat exchangers. The same considerations that apply to chemical fouling and scaling also apply to preventing struvite formation in heat exchangers. Keeping water temperatures below 65°C will help prevent struvite formation, as will restricting the amount of phosphorus added to the digester. Struvite can often be physically removed, and as it is a valuable mineral, many wastewater plants and businesses are looking into commercial recovery. Vivianite (ferrous phosphate) is a particular problem where ferric chloride (also known as pickle liquor) is added to sludge to control hydrogen sulfide emissions. High water temperatures can lead to the deposition of this hard, blue/green

BIOLOGICAL FOULING Algal fouling is often encountered where untreated river or canal water is used for cooling. Environmental regulations may prevent the use of chemical additives and also limit temperature increase, so algae quickly grow in what is an ideal environment. Using high velocities or even scraped-surface heat exchangers can prevent fouling, as can the use of construction materials such as copper or brass. A regular cleaning regime is usually necessary. Zebra mussels are an invasive species found across the world. They enter pipework as larvae and then colonize and grow. In worst cases, hundreds of tonnes of mussels have been removed from some water treatment works. They are relatively uncommon in heat exchangers, and can be controlled by keeping the velocity of the fluid through the exchanger above 2 m/s to prevent larvae attaching, and by regular flushing. In some wastewater plants, final filtered effluent (FFE) taken after the filter press is used as a free cooling medium. However, due to the high level of biological material contained in FFE, it has a high fouling potential and this can quickly occur, depending on the exact nature of both the FFE and the heat exchanger design. UV treatment of the FFE can help to reduce the biological load and therefore the potential for fouling, but cleaning normally relies on caustic cleaning-in-place systems. It is therefore important to specify heat exchangers and other equipment that can cope with such caustic cleaning materials. DEPOSITION FOULING This is the most common type of heat exchanger fouling and is caused by particulates in the treated fluid settling out on the surface of the heat exchanger. It

Environmental Science & Engineering Magazine

can usually be prevented by good heat exchanger design and choosing the right one for the job. Making sure that the fluid has sufficient velocity and pressure, and using corrugated tubes can prevent sedimentation. Scraped-surface heat exchangers can continually remove deposits to ensure efficient operation. Burn-on occurs where the water temperature is too high, causing sediments (particularly organic materials) to become baked on to the tube walls. It often occurs when a malfunction has arisen. For example, heating has continued while product flow has stopped, resulting in overheating of the material. The likelihood of burn-on can be reduced by good design of the overall system and interlocking the controls for both water and sludge pumps, so that if one stops, so does the other one. Control of the water temperature (ideally keeping it below 80°C) will also help prevent burn-on. Burn-on can usually be removed by physical or chemical cleaning.

For materials with high fouling potential, a scraped-surface heat exchanger, like the patented HRS Unicus Series, may be required.

manufacture of heat exchanger tubes. Using a material that is resistant to such corrosion yet maintains good thermal transfer properties, such as stainless steel, will overcome most of these issues. Good system design, for example to regularly remove grit, and regular cleaning will also help to prevent the formation of corrosion. Heat exchanger designers and engineers use a combination of materials, analysis and the calculated fouling factor (a mathematical value that represents the thermal resistance of the deposits) to ensure that the one recommended for a particular purpose resists fouling for as long as possible. Also, that if fouling does occur, it can be cleaned and dealt with efficiently and effectively.

CORROSION FOULING Corrosion fouling usually occurs in specific circumstances where either the material being treated, or the construction of the heat exchanger itself, is particu- Matt Hale is with HRS Heat Exchangers. larly susceptible to corrosion. Aluminum For more information, email: and copper can be highly reactive and fre- info@us.hrs-he.com quently suffer from galvanic corrosion or the formation of oxides on the tube surface where they have been used for the

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April/May 2020 | 53

ES&E NEWS CANADIAN RESEARCHER WINS 2020 STOCKHOLM WATER PRIZE

Drawing attention to the crisis of groundwater contamination and exploitation is the goal of a University of Guelph engineering professor, whose prestigious international water award was announced in March. Professor John Cherry, an adjunct professor in the University of Guelph’s School of Engineering, was named the 2020 winner of the Stockholm Water Prize on UN World Water Day on March 22. Cherry is the first hydrogeologist and the second Canadian to win the international award, which has gone to academics and organizations worldwide. Cherry would have addressed the opening session of World Water Week, organized by the Stockholm International Water Institute. However, that event was cancelled, due to the COVID-19 pandemic. “John has made incredible contributions to groundwater research that have had profoundly important global impacts, aligning perfectly with our institutional commitment to improve life,” said Malcolm Campbell, vice-president (research), at University of Guelph. Worldwide, groundwater quality is imperiled by pollutants, especially contaminants from agriculture such as fertilizer and other sources such as road salting, septic systems and industrial chemicals, said Cherry. www.news.uoguelph.ca

WEF MESSAGING TOOLKIT OFFERS ‘THANK YOU’ TO WATER WORKERS

The Water Environment Federation (WEF) is looking to highlight the importance of water services during the coronavirus pandemic by releasing a “toolkit” of graphics and messaging. These showcase how water professionals are providing essential services critical to a community’s ability to minimize the spread, flatten the curve, and support medical professionals’ efforts to provide care, conduct research and develop treatments. The “Water’s Worth it” toolkit is primarily designed as eye-catching, readymade messaging that can be utilized on social media platforms. It features ways 54 | April/May 2020

to teach children about the importance of water, while also focusing on the critical need for water and wastewater services and the dedicated professionals who work 24/7. This essential work is carried out by skilled workers with “quiet consistency” and is “largely invisible to the public,” stated WEF. Some of the messaging included with the toolkit also acknowledges the increased risk faced by many municipal water systems as people’s use of items such as gloves and cleaning wipes increase, as well as their time at home in general during the pandemic. It all naturally elevates the risk of clog-prone items being carelessly flushed down the toilet. Municipalities across Canada and the United States have seen an increase in wipes, gloves and other non-flushables in collection systems and pump stations. Collingwood, Ontario, officials said they have stepped up their anti-flush messaging as they too have seen spikes in items such as gloves and wipes clogging sewers and pumps because they were never meant to go down the drain.

For the secondary treatment upgrades, demolition of the aeration and clarifier tanks for stage one construction activities are complete and modifications to these structures have begun. Piles and lagging have been installed and excavations are underway to support the addition of the new clarifier tank.

NEW WASTEWATER SPREADSHEETS ADDED TO CANADA’S OPEN-DATA WEBSITE

Canada’s wastewater data is becoming more transparent thanks to Environment Canada’s latest additions to the federal Open Data website. Earlier this year, the federal government released the data under the Wastewater Systems Effluent Regulations (WSER) to show when and where sewage is released, and whether wastewater treatment facilities are meeting regulations as they relate to the Fisheries Act. The inclusion of free, on-demand access to machine-readable data files on sewage nationwide includes spreadsheet reports for a variety of datasets. The WSER data covers 2013 to 2018, with datasets about HAMILTON MAKING HEADWAY wastewater treatment types and discharge ON MASSIVE $340M WOODWARD point locations, concentrations of carboWWTP UPGRADES naceous biochemical oxygen demanding As the largest single water invest- matter and suspended solids, acute lethalment ever for the City of Hamilton, the ity test results, and volumes of effluent dis$340-million series of multi-stage, multi- charged from the final discharge point and year process upgrades for the Woodward from combined sewer overflow points. Wastewater Treatment Plant continues. www.open.canada.ca City officials are looking to enhance water quality in Hamilton Harbour by upgrading the facility as part of the Ham- REPORT PROVIDES ROAD MAP TO IMPROVE LEGIONNAIRES’ ilton Harbour Remedial Action Plan. New $165-million tanks will be added DISEASE RESPONSE to Woodward’s secondary treatment proA recent policy report, entitled “Eleccess to convert ammonia to less harm- tronic Registration Systems for Cooling ful nitrate, which will reduce ammonia Towers – Improving Public Health and emissions. Sustainability Outcomes,” published by The massive undertaking involves sev- the Urban Sustainability Directors Neteral sub-projects. These include replace- work (USDN) proposes a standardized, ment of the existing raw wastewater pump- yet flexible, template for cooling tower ing station with a new station, expansion registries that are designed to improve of secondary treatment to allow for nitri- health outcomes, address disparity in fication, adding tertiary cloth filtration affected populations, and increase water media for tertiary treatment, construc- and energy efficiency. tion of a new energy centre with standby Poorly maintained cooling towers can power, new chlorine contact tank and a disperse Legionella through contaminated new outfall. continued on page 62 Environmental Science & Engineering Magazine

NEWS

WATER STAGNATION AN ISSUE FOR SHUTTERED BUILDINGS

utilities on how to safely recommission buildings that had low, or no occupancy, Researchers at Indiana’s Purdue Uni- during the pandemic. versity have begun a field study to determine how water quality could change in shuttered buildings, like schools, sports CITIES UNDER LOCKDOWN venues and government offices, during RECORDING 40% DROPS IN AIR POLLUTION LEVELS the COVID-19 pandemic. The concern is that water left sitting for Air pollution levels are dropping at long periods of time could contain exces- unprecedented rates, with multiple studies sive amounts of heavy metals and patho- revealing a drastic drop in fine particulate gens concentrated in pipes. Researchers matter (PM2.5) pollution for most global fear this may be of even greater concern, locations under pandemic lockdown. if previously defunct hospital facilities Nine of ten key global cities experiare reopened to meet the growing need enced PM2.5 reductions over the same for healthcare. period in 2019. This is according to a new The study, funded by the National report from researchers at IQAir, a SwissScience Foundation’s Rapid Response based global air quality technology comResearch (RAPID) program, will charac- pany that selected cities with relatively terize disinfectant, heavy metal, and bac- high numbers of coronavirus cases and terial changes during extended building strict COVID-19 lockdown measures. closures, and then develop evidence-based The report’s findings show that cities plumbing remediation methods to address with historically higher levels of PM2.5 water quality deterioration. pollution experienced the most substanOnce completed, the study results will tial drops under lockdown. These include help guide building owners and water Seoul, South Korea (-54%) and Wuhan,

China (-44%). New Delhi, India, which frequently tops the world’s most polluted city lists, saw a 60% reduction in PM2.5 levels from March 23 to April 13. over the same period in 2019. In Ontario, Hind Al-Abadleh, a chemistry professor and chair of the environment division at the Chemical Institute of Canada, has been studying the impact of the pandemic on air quality in the province. Her data comes from provincial air quality stations in four Ontario metropolitan areas, gathered from January until April 10. Preliminary results show there’s been a 40% reduction in nitrogen dioxide in Kitchener, a 30% to 40% reduction in Toronto and a 40% reduction in Ottawa. Studies are also underway to determine if there are links between cities with severe air pollution, where lung health may be generally compromised, and deaths from COVID-19.

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WASTEWATER

Exploring treatment options to remove new contaminants in landfill leachate By Patrick Stanford

he growing need to prevent impacts to groundwater and surface water caused by landfills is driving developments in water treatment that may see application elsewhere. There has been a growing list of products including asbestos and PCBs that were once heralded as “wonder materials,” that have turned out to have negative impacts on the environment and people. Some of those impacts come from water that falls as precipitation on the landfill and then percolates through it, picking up potentially harmful materials like heavy metals, salts and more recently constituents of concern. Landfill operators have long become accustomed to building into their landfills, complex systems of impervious liners, piping, sumps and pumps to gather up this leachate and prevent it from leaking into surface and groundwater. Typical landfill procedure is to discharge leachate to the sewer for dilution and discharge to the environment. Other, more progressive landfills treat leachate to isolate and concentrate impurities in the water, so that most of the liquid meets relevant standards for release into surface water. Remaining concentrate is held back for further treatment. The big challenge for landfills is to capture and isolate enough impurities so that the bulk of the leachate can be permitted for discharge. That is particularly hard in the case of per- and polyfluoroalkyl substances (PFAS), which are considered environmentally problematic at nanograms per litre (parts per trillion) detection levels. What works for the demanding task of removing constituents of concern from leachate may well meet requirements for other types of industrial wastewater management too.

and it is important to understand the potential role of each. As full disclosure, note that Rochem Americas provides solutions around one particular type of

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April/May 2020 | 57

WASTEWATER tect against hazards present in industrial wastewater. This includes landfill leachate and may limit discharges to POTWs. • Oxidation processes – Oxidation processes use chemistry, electricity, light and other methods to break down organics into simpler compounds. Most landfill leachate contains ultraviolet (UV) inhibitors or quench agents, so that they just absorb the UV energy. Many POTWs have switched from chlorine disinfection to UV disinfection. This means they may have no choice but to reject landfill leachate because it can reduce the effectiveness of UV disinfection for the municipality’s own wastewater. • Activated carbon – Activated carbon works well for treating many kinds of Reverse osmosis has become a proven technology for landfill leachate treatment. effluent. It works by adsorbing contaminants, so the compounds stick to the surcontaminants of concern: landfill leachate to reduce treatment costs face of the carbon. The problem is that • Biological treatment – Biological before it enters the sewer. The problem other organics tend to have more suctreatment usually works well in the situa- is that biological treatment is not partic- cess than PFAS in adhering to the carbon tions for which it is designed, specifically ularly effective in treating most emerging molecules. Because those other organics involving degradable organic compounds. constituents of concern. There is increas- also adsorb onto the carbon, it takes a It can be useful for publicly owned treating concern among municipalities that lot of activated carbon to remove them ment works (POTWs), or pretreatment of their systems are not sufficient to pro- before the PFAS get to the front of the line for removal. • Ion exchange – Ion exchange also suffers from interference of other organics before the process can get working on removing PFAS. There are some PFAS specific ion exchange systems available, but they still face the problem of fouling by organic compounds. • Evaporation – Evaporation is an effective technology, particularly as some operations have been able to fire evaporators with their own landfill generated gas Insitu Groundwater Contractors supply. One potential risk is the transfer of the constituents of concern into the • Dewatering systems atmosphere. Many of these compounds • Mobile groundwater treatment systems have relatively low vapour pressures, so • Well and pump installation and maintenance • Pump, filter, generator rentals they tend to stay within the liquid. While • Sediment tank rentals further research needs to be done on this P: 519-763-0700 F: 519-763-6684 • Insitu groundwater remediation systems issue, initial results appear promising. 48 Dawson Road www.insitucontractors.com Guelph, ON N1H 5V1 • Incineration – Incineration will deal with the problem, if it is done at a high enough temperature. One problem with this treatment technology is the cost, which can be about $0.25 per litre, plus hauling costs. Another problem is the limited availability of suitable incinerators. • Membrane technologies – Membrane technologies offer the ability to separate out a wide range of constituents of concern (again, as full disclosure, this is the 58 | April/May 2020

Environmental Science & Engineering Magazine

technology Rochem Americas designs and manufactures). Reverse osmosis (RO) is one type of membrane technology.

tinue to tighten? Probably, as there are the company providing that service may thousands more compounds that are go out of business or increase prices to a not yet on the regulatory radar. We can level beyond what you can pay. Landfills expect that as the ability to test for more that depend on POTW services through A CLOSER LOOK AT materials grows, there will come more a sewer connection are particularly vulREVERSE OSMOSIS FOR requirements to test for those materials. nerable to a decision that will stop the WASTEWATER TREATMENT From this we can note that the issue leachate processing solution cold. RO uses a semi-permeable membrane of PFAS and other constituents of conIt is important for landfill operators to remove ions, molecules and larger cern is more of a politically driven pro- and anyone else who manages industrial particles from the water being treated, cess, rather than scientific. We can argue wastewater to stay informed and take such as landfill leachate. A pump is used about the toxicology of materials like action when appropriate. to push the leachate against the mem- PCBs and asbestos, but public sensitivity brane. Smaller molecules, such as water, about these substances is moving faster Patrick Stanford is with pass through the membrane, while larger than our understanding about the sci- Rochem Americas, Inc. Email: pat@rochemamericas.com particles stay behind. ence-based toxicology and risk. The result is that the concentrate Be careful about solutions that depend (residual leachate) is retained on the pres- on outside entities. If you’re using thirdsurized side of the membrane and the party incineration, for example, note that permeate (RO-treated effluent) can pass to the other side. Recent improvements in membrane INTERPROVINCIAL CORROSION CONTROL technology, plus improved systems for Leaders in the Cathodic Protection Industry…Since 1957 keeping the membranes clear, mean that CORROSION CONTROL PRODUCTS fouling does not impede the efficiency of Burlington, Ontario Canada the process. RO is a well-established and Regional Offices: Montreal, Calgary proven technology in use worldwide Lewiston, New York, USA for desalination of seawater to produce Tel: 905-634-7751 • Fax: 905-333-4313 freshwater. Cargo and passenger ships, www.Rustrol.com as well as naval vessels use RO to provide drinkable water. It is also used in high purity industrial process applications such as manufacturing of electronic components, pharmaceuticals, chemicals and medical applications. Since the late 1980s, RO has become a proven technology for landfill leachate treatment and is widely used at landfills across Europe, with over 300 leachate treatment systems installed worldwide, and tens of systems running in the U.S. and at least one in Canada. SO, WHAT CAN WE LEARN FROM ALL THIS? One lesson is that the push for tighter standards for landfill effluent is largely a technology-driven phenomenon. Just a few years ago, it was barely possible to measure concentration in the parts-permillion range. Now we are able to measure down to parts per trillion. So, it can be said that the landfill sector is being asked to reach extreme levels of contaminant management for leachate, largely because it is now possible to measure it. Will requirements for leachate conwww.esemag.com @ESEMAG

April/May 2020 | 59

PRODUCT & SERVICE SHOWCASE

AREA/VELOCITY FLOW METER

Flow-Tronic has introduced the new version of its flagship sensor, the RAVEN-EYE 2®. This complete redesign of the sensor brings non-contact flow measuring technologies to higher level standards. What is new? Lower power consumption; minimum velocity of only 0.08 m/s (0.26 ft/s); new hybrid radar antenna; significant progress on signal processing. Compatibility remains with all existing loggers and monitors. The enclosure remains the same and thus is compatible with existing brackets. ACG – Envirocan T: 905-856-1414 F: 905-856-6401 E: sales@acg-envirocan.ca W: www.acg-envirocan.ca

ELECTRIC ACTUATOR

METERING PUMPS

Blue-White® metering pumps, including the Proseries-M® MD-3 Multi-Diaphragm Chemical Feed Pump, are subjected to a full 24 hours of rigorous testing to ensure delivery of a high performance, trouble free product. A 4-20mA signal generator is used to speed up and slow down the pump for 24 hours to test components and electronics. This is why Blue-White® stands by our products and warranties. Blue-White Industries T: 714-893-8529 F: 714-894-9492 E: sales@blue-white.com W: www.blue-white.com www.proseries-m.com

Chemline’s new ERF “Fast Acting” Electric Actuator is a reversible rotary unit with output torques up to 180 in.-lb. Ideal for all Chemline ball valves up to 2 ." 6.0 sec. for 12VAC/VDC and 3.5 sec. for 24VAC/ VDC. CSA special inspection labeled, compact, lightweight with a NEMA 4X plastic housing. The handle provides manual override and position indicator. Chemline Plastics T: 800-930-CHEM (2436) E: request@chemline.com W: www.chemline.com

FLOW MONITORING SYSTEM

STORMWATER MANAGEMENT

The GRAF EcoBloc Inspect Flex system can be used for stormwater infiltration, retention or rainwater harvesting. The EcoBloc system can be installed at a depth of up to 16.5 feet. Up to 14 layers are possible and the system can withstand a capacity of 60 tons. The system is easily cleaned by pressure washing and designed for a service life of over 50 years. BARR Plastics T: 1-800-665-4499 E: info@barrplastics.com W: www.barrplastics.com 60 | April/May 2020

BW DIGI-METER® F-2000 Series of Electronic Insertion Style Paddlewheel Flowmeters monitor flow in a broad range of applications. F-2000 will display flow rate, total flow, and includes an NPN open collector output point for communication with data loggers, SCADA systems, and other external devices. Additional features: 4-20 mA / 0-10 VDC, batch processing, a high/ low flow rate alarm output, electronic display/communication enclosure can be panel, wall, or pipe mounted. Blue-White Industries T: 714-893-8529 F: 714-894-9492 E: sales@blue-white.com W: www.blue-white.com

ROAD MAINTENANCE

Consider a proactive approach to road maintenance this year. Many municipalities and private companies are utilizing Denso’s polymer modified–bitumen asphalt joint tapes to prevent water infiltration at joints. DensoBand and Denso Reinstatement Tape provide a permanent, flexible barrier between hot asphalt and steel, concrete and existing asphalt. Great for bridges, railway crossings and utility cuts. Contact Denso for more information. Denso North America T: 416-291-3435 E: sales@densona-ca.com W: www.densona.com

Environmental Science & Engineering Magazine

PRODUCT & SERVICE SHOWCASE

GRIT TRAP

The new GritWolf® grit trap uses an innovative two-chamber design and contact settling to reduce footprint and remove the finest grit particles as well as FOG. The GritWolf offers up to 95% of the grit of grain size ≥ 75 µm, with the smallest footprint and shallowest depth. Contact us at 704-990-2053 or marketing@hhusa.net for more information. Huber Technology T: 704-990-2053 F: 704-949-1020 E: huber@hhusa.net W: www.huber-technology.com

CATCH BASIN INSERT

The LittaTrap Catch Basin Insert is a low-cost, innovative technology that prevents plastic and trash from reaching our waterways. Designed to be easily retrofitted into new and existing stormwater drains, the LittaTrap is installed inside storm drains and when it rains, catches plastic and trash before it can reach our streams, rivers and oceans. Imbrium Systems T: 800-565-4801 E: info@imbriumsystems.com W: www.imbriumsystems.com

www.esemag.com @ESEMAG

OGS/HYDRODYNAMIC SEPARATOR

The new Stormceptor® EF is an oil grit separator (OGS)/hydrodynamic separator that effectively targets sediment (TSS), free oils, gross pollutants and other pollutants that attach to particles, such as nutrients and metals. The Stormceptor EF has been verified through the ISO 14034 Environmental Management – Environmental Technology Verification (ETV). Imbrium Systems T: 800-565-4801 E: info@imbriumsystems.com W: www.imbriumsystems.com

TWIN SHAFT GRINDER

The N.Mac® Twin Shaft Grinder fragments various materials for wastewater treatment, biogas and biomass plants, food processing, animal processing, and other waste and industrial applications. Channel housing for effluent channels, pump stations or as horizontal units for waste stream processing. Inline housing design allows flanged piping assemblies upstream from a pump. Can be stacked for successive particle size reduction. NETZSCH Canada T: 705-797-8426 F: 705-797-8427 E: ntc@netzsch.com W: www.pumps.netzsch.com

WATERTIGHT DOORS

Huber, a proven German manufacturer, now provides watertight doors that allow safe access to tanks for construction and/ or maintenance. Doors can be provided as round or rectangular for installation onto existing concrete surfaces or cast-inplace in new concrete. They can handle heads up to 30 m and hold pressure in seating and unseating directions. Huber’s watertight doors can greatly reduce construction and maintenance costs and dramatically improve safety/access. Pro Aqua T: 647-923-8244 E: aron@proaquasales.com W: www.proaquasales.com

HYPERBOLOID MIXERS

Invent Environment is the manufacturer of hyperboloid mixers which have revolutionized anoxic and swing zone mixing. Invent provides low-shear, efficient mixers with no submerged motors or gear boxes for easy access for maintenance. They have now released the Hyperclassic Mixer Evo 7 which has increased the number of motion fins and adjusted the geometry of the mixer to maximize mixer efficiency, reducing operation costs even further. Pro Aqua T: 647-923-8244 E: aron@proaquasales.com W: www.proaquasales.com

April/May 2020 | 61

ES&E NEWS continued from page 54

water droplets that are created as part of the cooling process. Once inhaled, the bacteria can cause Legionnaires’ disease, an acute form of pneumonia, and the less severe Pontiac fever. According to a study, published in April 2018 in Current Environmental Health Reports, cooling towers were

Advertiser INDEX COMPANY PAGE ACG-Envirocan...................................63 ACO Systems......................................45 All-Weld Company.............................21 Associated Engineering....................20 AWI......................................................27 Barr Plastics.......................................37 BDP Industries.....................................2 Blue-White............................................7 Boerger...............................................44 CB Shield............................................35 Chemline Plastics..............................31 Crane Pumps & Systems.....................3 Denso..................................................15 Endress+Hauser.................................39 Flottweg...............................................9 Harmsco Filtration Products............29 Huber Technology.............................25 Imbrium Systems..............................64 KGS Environmental Group................13 Netzsch Canada...................................8 Nexom................................................23 Orival..................................................11 OWWA.................................................53 Pro Aqua...............................................5 RTS Companies..................................42 RV Anderson.......................................29 Sentrimax...........................................49 SEW Eurodrive...................................55 SPD Sales......................................50, 51 Stantec...............................................55 Troy-Ontor..........................................33 Vanton Pump & Equipment..............17 Veolia..................................................19 Victaulic..............................................24 Vissers.................................................43 Walkerton Clean Water Centre.........14 WEFTEC..............................................40

62 | April/May 2020

implicated or suspected in the majority of Legionnaires’ disease outbreak-associated deaths examined during the study period between 2006-2017. The report argues that cities, states and water utilities should create electronic cooling tower registration systems to improve surveillance and response to cases, as well as to prevent exposure to Legionella bacteria by encouraging proper maintenance of cooling towers. According to Health Canada, “the average number of reported cases of Legionnaires’ disease is generally less than 100 per year. However, the actual number of cases is thought to be much higher, as many people with pneumonia may not be tested for infection with Legionella.” Most North American cities do not track the location of cooling towers and are “forced to rely on imprecise methodologies during public health emergencies,” the report says, adding that there is a “continued tolerance of widely divergent maintenance practices by building owners.” “Cooling tower registries are a demonstrably effective and proactive tool for improving public health and fulfilling water efficiency goals,” said Patrick Ryan, Chief Building Official from Vancouver, a key participant city in the new report. According to the report, registries provide municipalities with a management tool for maintenance record-keeping and support to building owners to meet regulations. Registries can also be a crucial tool to measure key sustainability performance indicators, aiding jurisdictions in evaluating the effectiveness of a building’s water conservation plans and identifying areas for improved energy efficiency. Cooling towers can be a significant source of water demand for a building, representing 20 – 50% of total water usage, according to the report, which added that poor management practices result in millions of wasted gallons of water per year in a single cooling tower. www.usdn.org

NEW STUDY RANKS CANADA’S ENVIRONMENT RECORD NEAR MIDDLE OF OECD PACK A new study ranks Canada 12th out of 33 high-income countries on a wide range of environmental indicators that relate both to the protection of human health, such as air pollution, and the preservation of Canada’s ecosystems, such as water quality. Canada ranks 12th overall, with a score of 67 out of a possible 100 on a list of Organization for Economic Cooperation and Development (OECD) countries that produced an average score of 62.2. Many of the top-ranked countries in this second edition of the study are clustered closely together. For example, Canada and 2nd place New Zealand (which scored 74.7) are less than eight points apart. Sweden ranks 1st with a score of 80, while South Korea came in last at 41.4. The Fraser Institute, an independent, non-partisan Canadian policy thinktank, determined that for some critical categories, Canada ranks particularly high, including 1st and 4th best on two separate air quality measures. It is 4th best in fertilizer use and 8th best for low-emissions electricity production, namely electricity generated by nuclear power and renewable energy sources. Under the heading of protecting human health and well-being, the study examined air quality, water quality, and greenhouse gases. Under the objective of protecting ecosystems, the study considered six core categories: air emissions, water resources, forests, biodiversity, agriculture, and fisheries. For water quality, Canada ranks 13th out of 33 countries, based on the two indicators that assess the health risks posed by water pollution. These are access to improved sanitation facilities and access to improved water sources. Canada ranks 19th for its wastewater treatment rate (the Netherlands topped the ranking) and 4th for the intensity of use of its water resources. The study was released April 21, the day prior to Earth Day. Read the full report by visiting: www.fraserinstitute.org/ studies/environment

Environmental Science & Engineering Magazine

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