Wastewater Systems Effluent Regulations 2018 Annual Report

This report summarizes information submitted by owners and operators of Canadian wastewater systems subject to the Wastewater Systems Effluent Regulations (WSER) for 2018.

The WSER are established under the Fisheries Act and aim to reduce the impacts of wastewater pollution on Canadian waterways. They came into force in 2012 and are applicable to wastewater systems that are designed to collect, or collect, at least 100 m³ or more of wastewater per day. The WSER set national baseline effluent quality standards that are achievable through secondary wastewater treatment. Additionally, they prohibits the release of effluent that is acutely lethal to rainbow trout^{Footnote 1} .These standards came into effect in January 2015. The WSER also include effluent monitoring, reporting and record keeping requirements.

Some wastewater systems need time to upgrade to be able to meet WSER effluent quality limits. Owners or operators of these systems had until June 2014 to apply for a transitional authorization to exceed these limits for a limited time. Transitional authorizations were issued to 65 systems, expiring at the end of 2020, 2030, or 2040. These deadlines were based on the level of risk to the environment.

In 2014 and in 2018, equivalency agreements were signed with the Yukon Territory and the Province of Québec. These agreements considered the respective territorial and provincial regulatory regimes as equivalent to the WSER and that the regulations no longer apply. Municipal and provincial wastewater systems in these jurisdictions are no longer subject to the WSER. Approximately 650 wastewater systems are covered by the equivalency agreement in Québec and three in the Yukon.

By the end of 2018, 2,316 wastewater systems out of an estimated 2,407 submitted an identification report under the WSER. Most of these wastewater systems (87%) are owned by municipalities or other local governments. Wastewater lagoons make up more than half of the wastewater systems in Canada. Mechanical systems make up approximately one third of wastewater systems, and the remaining systems have no treatment.

Of the 2,316 systems that submitted identification reports, 74% submitted all required monitoring reports. The remaining 26% of systems did not submit one or more monitoring report. Most (89%) systems did not report any exceedances of the effluent quality limits, while 19% reported at least one exceedance. A total of 368 systems tested for acute lethality and 88% of these systems reported no failures.

A total volume of 5.69 billion m³ of effluent was released from wastewater treatment plants in 2018. Sixty-three percent of effluent was released from systems subject to WSER, and the remaining while the remaining 2.11 billion m³ was reported under the Québec equivalency agreement. From the total volume of 5.69 billion m³ of released effluent, 89% met the WSER and Québec equivalency agreement effluent quality limits. The remaining 9% was undertreated effluent and did not meet the limits, and 2% was untreated effluent. These volumes do not include releases from combined sewer overflows points (CSO) or any other discharges occurring outside the final discharge point.

In Canada, as of 2018, 81 systems that are subject to the WSER, had at least one CSO point. A total reported volume of 190 million m³ of effluent was released from CSOs in 2018.

The WSER are enforced by Environment and Climate Change Canada. Compliance issues are followed-up on and enforcement action is taken in accordance with the Compliance and Enforcement Policy for the Habitat Protection and Pollution Prevention Provisions of the Fisheries Act (Environment Canada 2001c). As part of the quality review of this report, the data and information in the report were reviewed by Enforcement Branch personnel. 

1.0 Introduction

The Wastewater Systems Effluent Regulations (WSER), developed under the Fisheries Act, came into force in 2012. The Regulations deliver on a federal commitment in the 2009 Canadian Council of Ministers for the Environment (CCME) Canada-wide Strategy for the Management of Municipal Wastewater Effluent (CCME Strategy) to establish national baseline effluent quality standards. In Canada, the management of wastewater involves all levels of government, which has led to inconsistent regulatory regimes across the country. As a result, treatment levels range from very good in many areas to poor or no treatment, mostly on the coasts. The CCME Strategy represents a collective agreement to ensure that wastewater effluent is managed under a harmonized framework that is protective of the environment and human health, with each jurisdiction using its authority.

The WSER apply to wastewater systems that deposit effluent to surface water^{Footnote 2}  , and that collect an average daily volume of 100 m³ or more of influent during a calendar year. Systems that are subject to the WSER typically serve populations of at least 250 individuals. Due to the extreme climatic conditions and remoteness of Canada’s Far North, the WSER do not apply to wastewater systems located in Nunavut, the Northwest Territories, or north of the 54^th parallel in Québec or Newfoundland and Labrador. The WSER also do not apply in Yukon and to certain wastewater systems in Québec, as equivalency agreements with Yukon and Québec for the WSER came into effect in November 2014 and October 2018, respectively. Under equivalency, the Governor in Council orders that the WSER do not apply for wastewater systems that are subject to a provincial or territorial regulatory regime that is in force and equivalent in effect to the WSER^{Footnote 3} . This applies to municipal and provincial wastewater systems. Federal and Indigenous systems in Québec are subject to the WSER.

The WSER set discharge limits for deleterious substances that are indicative of overall effluent quality that came into effect in 2015^{Footnote 4} . These limits are achievable through a secondary level of wastewater treatment, or equivalent. Secondary treatment removes over 95% of the total mass of conventional pollutants in wastewater. Significant amounts of non-conventional pollutants and bacteria that may be present are also removed through such treatment. Provinces or other jurisdictions may set requirements that are more stringent. In addition to effluent quality standards, the WSER also have requirements for effluent monitoring, record keeping and reporting.

There are three types of authorizations under the WSER for the temporary exceedance of all or some of the WSER effluent quality standards: transitional authorizations, temporary bypass authorizations and temporary authorizations to deposit un-ionized ammonia. In order to receive an authorization, specific requirements under the WSER must be met.

1. A transitional authorization provides time for a wastewater system not meeting the effluent quality standards to upgrade. Systems had until June 30, 2014 to apply. Qualifying systems were granted a transitional authorization until the end of 2020, 2030 or 2040 to upgrade based on risk-based criteria.
2. A temporary bypass authorization allows for the bypass of a treatment process at the final discharge point in order to conduct planned construction or maintenance work, or in response to an anticipated event that is beyond the control of the owner or operator of the system and, as a result, exceed the effluent quality standards.
3. A temporary authorization to deposit un-ionized ammonia allows for a wastewater system that is at secondary level of treatment to discharge effluent that is acutely lethal due to the concentration of un-ionized ammonia if the receiving environment has the capacity to assimilate it.  

This report provides a summary of the information provided by owners or operators of wastewater systems in identification reports up to the end of 2018 as well as in effluent monitoring reports, and combined sewer overflow reports, for those with combined sewers, for 2018. This report also provides information on authorizations issued under the WSER in 2018.

Information obtained through equivalency agreements are  also included in this report. The Yukon equivalency agreement came into effect in 2014 and the Québec equivalency agreement came into effect in 2018. Information for systems covered under Québec are no longer reported directly to ECCC. Instead, reports are submitted to the province of Québec and are provided to ECCC under the agreement. In this report, all information on systems covered under the equivalency agreement has been provided directly by Québec and the Yukon. Information provided under equivalency agreements includes the number of wastewater systems under the agreement, monitoring results and the volume of effluent deposited from each system.

All the wastewater data ECCC receives is released publicly on the Wastewater webpage in the form of reports, datasets and maps.

The WSER are enforced by Environment and Climate Change Canada in accordance with provisions of the Compliance and Enforcement Policy for the Habitat Protection and Pollution Prevention Provisions of the Fisheries Act (Environment Canada 2001). Enforcement personnel enforce the provisions of the Fisheries Act and accompanying regulations with an emphasis on preventing harm to fish, fish habitat, or the use of fish by humans, caused by physical alteration or pollution of waters frequented by fish. The policy sets out a range of possible responses to offences that can be used by enforcement inspectors, including warnings, inspector’s directions, ministerial orders, injunctions, prosecution and civil suits by the Crown for the recovery of costs. If an inspector confirms that an infraction has been committed, the inspector will select the appropriate response based on the following criteria: nature of offence, effectiveness in achieving the desired result with the offender, and consistency.

2.0 WSER reporting

Owners or operators of wastewater systems are required to submit an identification report and regular effluent monitoring reports. For wastewater systems with combined sewers, combined sewer overflow reports must also be submitted. The following sections provide more information on these reports and a summary of the data submitted to Environment and Climate Change Canada.

2.1 Identification reports

Owners or operators of existing wastewater systems subject to the WSER were required to submit an identification report to Environment and Climate Change Canada (ECCC) by May 15, 2013. New wastewater systems must submit an identification report within 45 days after the wastewater system comes into operation. Identification reports include information on the system owner, type of treatment, operational details and location of discharge points.

This section provides information on identification reports submitted by the end of 2018 as well as a breakdown of wastewater systems by ownership and treatment type.

2.1.1 Summary for the submission of identification reports

As of the end of 2018, 2,316 identification reports had been submitted out of an estimated total of 2,407 wastewater systems. Table 1 presents the number of submitted identification reports and the estimated number of those missing by province and territory. This includes the wastewater systems covered under the equivalency agreements with Québec and Yukon.

The estimated number of missing identification reports consists of wastewater systems that are known or are suspected to be subject to the WSER, based on estimates provided in the CCME strategy, and have not submitted an identification report under the WSER. These systems are owned and operated by First Nations, municipalities, governments or private companies across Canada. In 2018, Manitoba, Alberta, and Saskatchewan had the highest estimated number of missing identification reports under the WSER.

The high rate of submission of Québec identification reports is likely due to the result of the publication of the equivalency agreement, which finalized, results in the WSER not applying to most wastewater systems in the province,^{Footnote 5} leading additional identification reports were provided to ECCC under the equivalency agreement. 

Table 1. Identification reports submitted under the WSER or under an equivalency agreement* and estimated number of systems who are missing an identification report in 2018 by province and territory.

2.1.2 Overview of wastewater systems with identification reports

Table 2 shows the number of wastewater systems reporting by the end of 2018 by owner type as indicated in the identification reports under the WSER or an equivalency agreement. Most identified wastewater systems are owned by municipalities and other local authorities, such as regional governments (87% of systems). Indigenous communities also own or operate wastewater systems, representing 8% of the submitted identification reports. The remaining systems are owned or operated by federal authorities or owners falling into the “other” category.

Wastewater systems owned by private companies are classified in the “other” category. Private companies may own wastewater systems that serve municipalities, camps, or recreational areas.

Table 2. Identification reports submitted by owner type

2.1.3 Wastewater treatment type

Based on information reported, wastewater systems were divided into three categories:

• No Treatment: Typically in the form of a pipe that extends into a waterbody and discharges continuously with no treatment. Wastewater systems limited to screening or grit removal are included in this category.
• Lagoon: In-ground ponds where wastewater is held for a specified time, known as the hydraulic retention time, and undergoes physical and biological treatment. Lagoons can either discharge intermittently, typically once or twice a year, or on a continuous basis. Types of lagoons can vary and include facultative, aerobic, anaerobic and aerated lagoons.
• Mechanical: Treatment technologies, other than lagoons, that use mechanical components such as tanks, pumps, blowers, screens and grinders to treat wastewater. This category includes systems with primary level of treatment such as clarifiers as well as those with more advanced treatment such as activated sludge and rotating biological contactors.

Table 3 and Figure 1 provide a summary of the number of wastewater systems by treatment type and by province and territory. The most common type of wastewater system in Canada is lagoon (59%), followed by mechanical (31%), with the remaining systems (10%) depositing untreated effluent. Wastewater systems with no treatment are located in Newfoundland and Labrador, Nova Scotia, British Columbia and Québec, some of which have transitional authorizations under the WSER.

Table 3. Summary of the number of wastewater systems by treatment type and by province and territory

Figure 1. Map of the wastewater systems across Canada by treatment type

2.2 Effluent monitoring report summary

Effluent monitoring reports are submitted either annually or quarterly, depending on both the volume of effluent discharged by the wastewater system and whether the system discharges continuously or intermittently. The information found in effluent monitoring reports includes:

• total volume and number of days effluent was discharged
• average concentrations of carbonaceous biochemical oxygen demanding matter (CBOD) and suspended solids (SS); and
• results of acute lethality tests, if applicable

Of the 2,316 systems that submitted identification reports by the end of 2018, 1,719 of these systems submitted all required effluent monitoring reports.

Table 4. Summary of status of effluent monitoring reports for 2018 by province and territory

* –Yukon and Québec systems covered under equivalency agreement are not required to submit acute lethality data due to equivalency agreements. 

2.2.1 CBOD and SS test results

Table 5 below shows the number of systems broken down by province that exceeded the CBOD or suspended solid limits of 25 mg/L under the WSER and equivalency agreements, along with the total number of systems with exceedances and the total number of systems that met the standards. Some systems exceeded both the standards for CBOD and suspended solids. Systems are considered as exceeding the effluent quality standards if there is at least one reported exceedance in any of the reporting periods in the calendar year. Overall, 77% of wastewater systems who submitted a monitoring report met the CBOD and suspended solids standards during all periods reported in 2018.

Figures 2-6 present the breakdown of systems that met and exceeded the effluent quality standards by treatment type. The majority of reported exceedances came from lagoon wastewater systems, followed by systems with no treatment. For a more detailed breakdown, please see Supplementary Data Table 1 and Supplementary Data Table 2 in Annex 4.3.

Overall, wastewater systems had greater difficulties meeting suspended solids compared to CBOD with 416 systems exceeding suspended solids and 279 systems exceeding CBOD. A total of 182 lagoon systems reported exceedances of suspended solids compared to 78 which reported exceedances of CBOD. The larger number of suspended solids exceedances may be attributed to algae growth that is common lagoon systems.

Wastewater systems that received transitional authorizations under the WSER are not included in the effluent monitoring statistics shown in Table 5 and Supplementary Data Tables 1 and 2. These systems are not required to achieve the WSER effluent quality standards until the deadline set in the transitional authorizations (refer to section 3.1).

Table 5. Summary of CBOD and SS results in 2018, by province and territory.

*This represents the total number of systems that had at least one reported exceedance of CBOD or SS. Some systems in this category had both CBOD and SS exceedances.

**- Yukon and Québec provide effluent quality data to Environment and Climate Change Canada for systems subject to the equivalency agreements.

Figure 2. Summary of CBOD and SS results in 2018 for wastewater systems in Canada by treatment type

*-25/25 refers to the limit of 25 mg/L for CBOD and SS, under the WSER and as enforced by the province of Québec under the equivalency agreement

Figure 3. Map of systems meeting the CBOD limits in 2018 for wastewater systems in western Canada

Figure 4. Map of systems meeting the CBOD limits in 2018 for wastewater systems in eastern Canada

Figure 5. Map of systems meeting the SS limits in 2018 for wastewater systems in western Canada.

Figure 6. Map of systems meeting the SS limits in 2018 for wastewater systems in eastern Canada

2.2.2 Acute lethality testing results

The WSER require that wastewater systems discharge an effluent that is not acutely lethal. For the purposes of the WSER, “acute lethality” means that the effluent at 100% concentration kills more than 50% of the rainbow trout subjected to it during a 96-hour period^{Footnote 6} .

Under the WSER, owners or operators of wastewater systems discharging annual average daily effluent volumes greater than 2,500 m³ are required to determine and report on the acute lethality of the effluent. If owners or operators test for acute lethality for any other reason, they must also report the results. Table 6 and Figure 7 summarize the results of the acute lethality tests performed in 2018. Figures 8 and 9 present a summary of acute lethality test results across Canada. Acute lethality results are not required to be submitted under equivalency agreements and are not included in this report. Some acute lethality test results were submitted under the regulations by Québec municipalities in 2018 before the equivalency agreement was finalized. These test results are available on the Wastewater Systems Effluent Regulations Reported Data .

A total of 368 wastewater systems tested for acute lethality in 2018, with 88% of systems passing all acute lethality tests. Of the systems reporting an acute lethality test failure, 52% were lagoon systems, 46% were mechanical systems, and the remaining 2% came from systems with no treatment. For a more detailed breakdown of acute lethality test results by province please see Supplementary Data Table 3 in the Annex section 4.3.

Table 6. Summary of reported acute lethality test results, by province

* –Yukon and Québec covered under equivalency agreement are not required to submit acute lethality data due to equivalency agreements. 

Figure 7. Reported acute lethality test results in Canada by treatment type in 2018

Figure 8. Map of the acute lethality results in 2018 for wastewater systems in western Canada

Figure 9. Map of the acute lethality results in 2018 for wastewater systems in eastern Canada

2.2.3   Total effluent volumes

Wastewater systems are required to monitor and report their effluent flows at the final discharge point under the WSER. Québec and Yukon provide effluent volumes to ECCC for systems that are subject to equivalency agreements.

Figure 10 demonstrates the total reported effluent volume discharged via the final discharge point, by province and territory. These volumes do not include discharges of wastewater from combined sewer overflow points.

A total volume of 5.69 billion m³ of effluent was reported as being discharged from the final discharge point in 2018. Of this total, 3.58 billion m³ of effluent was reported as being discharged from systems subject to WSER, while the remaining 2.31 billion m³ of effluent was reported under an equivalency agreement. By province, Québec reported the highest volume of effluent at 2.11 billion m³ (37%). Ontario reported the second highest volume at 1.96 billion m³ (34%), followed by British Columbia at 647 million m³ (11%) and Alberta at 387 million m³ (7%). The remaining provinces and Yukon each deposit less than 5% of the total effluent deposited.

Figure 10. Total reported effluent volume (million m³) by province and territory

2.2.4   Effluent volumes discharged by treatment level

Table 7 shows the volume effluent discharged from the final discharge point of wastewater systems in 2018 broken down by effluent quality for each province. Wastewater effluent is identified as either undergoing “No Treatment”, being “Undertreated", or “Meets 25/25" effluent quality standards as defined below:

• No Treatment: Effluent deposited from a wastewater system with no treatment process in place. Wastewater systems limited to screening or grit removal are included in this category
• Undertreated: Effluent deposited from a wastewater system with treatment processes in place but systems are unable to meet the effluent quality standards for CBOD and suspended solids under the WSER or Québec equivalency agreement
• Meets 25/25: Effluent deposited from a wastewater system with treatment processes in place and met the effluent quality standards for CBOD and suspended solids under the WSER and Québec equivalency agreement

Overall, 89% of the reported total volume of effluent that was deposited across Canada met the WSER effluent quality standards.  Undertreated effluent represents 9% of the reporting effluent volume deposited. Untreated wastewater represents 2% of the total effluent deposited in Canada.

Undertreated and untreated effluent is mainly discharged from coastal areas or large water bodies in British Columbia, Newfoundland and Labrador, Nova Scotia, and Québec. Figure 11 shows wastewater systems based on their level of treatment across Canada including those that are untreated, undertreated, secondary (meets the effluent quality limits) and have advanced treatment (treated beyond a secondary level of treatment). A number of wastewater systems that discharge untreated or undertreated wastewater were issued a transitional authorization expiring in 2020, 2030, or 2040. For a full list of transitional authorization holders refer to the transitional authorization registry on the Wastewater webpage.

Figure 11. Map of the wastewater systems across Canada by treatment level

Table 7. Summary of effluent deposited by treatment level, by province in millions m³ for the year 2018.

* - The province of Québec has provided effluent data and effluent treatment levels to ECCC

2.3 Combined sewer overflow reports

Many older municipalities in Canada have combined sewers that collect both storm water and wastewater. Combined sewers are designed to discharge untreated wastewater when the volume collected exceeds the capacity of the system due to heavy rainfall or snowmelt. The WSER require owners or operators of wastewater systems with combined sewers to submit an annual report on the total volume and the number of days wastewater is discharged per month via combined sewer overflow (CSO) points as a result of precipitation. 

2.3.1 Wastewater systems with CSO points

The following table presents the number of wastewater systems in each province that have at least one CSO point. There are a total of 671 systems in Canada that reported having at least one CSO point, as presented in Table 8. Most wastewater systems with identified CSO points in Canada are located in Québec. Ontario also has a significant number of systems with CSO points out of systems that are subject to the WSER.

Table 8. Number of wastewater systems with at least one combined sewer overflow point, by province and territory

* Information on Québec municipal systems with at least one CSO point was provided by the province of Québec.

A complete list of the 81 wastewater systems that reported having a combined sewer system subject to the WSER can be found in Annex 4.2. More information on the number of CSO points in the province of Québec is available through Environment and Climate Change Canada’s Wastewater Systems Effluent Regulations Reported Data .

2.3.2   CSO points and volume by province and territory

Combined sewer systems have multiple points at which the combined sewer can overflow, discharging untreated wastewater. Systems must identify each individual point where a CSO can occur in their identification report, and must report annual volumes from each of these points.

Figure 12 presents the total reported number of CSO points in each province and the total report volume of untreated wastewater discharged from these points in 2018. There are approximately a total of 6,170 CSO points in Canada, as shown in Figures 12 and 13. However, of these 6,170 points in Canada, 1,015 CSO points report discharges to WSER, as the CSO points in Québec are not subject to the CSO reporting requirements under the WSER.

Ontario has the majority of CSO points subject to the WSER (50%), followed by Nova Scotia (23%), New Brunswick (13%), British Columbia (5%), and Manitoba (4%). The total reported volume under the WSER is 190 million m³. Of the reported volumes, British Columbia is responsible for the highest volume of untreated effluent discharged from CSO points (50%). Nova Scotia and Ontario reported 24% and 10% of the volume discharged by CSOs, respectively. The remaining volume of effluent discharged by CSOs come from Alberta, Manitoba, and New Brunswick, each discharging less than 10% of the national total. No data is available for CSO volumes in Québec as this data is not required to be reported under the Québec regulations.

Figure 12. Number of CSO points and total volume of CSO effluent discharged by province and territory under the WSER

Figure 13. Number of CSO points in 2018 by province and territory

Figure 14. Map of the combined sewer systems and their volumes of effluent in 2018 for wastewater systems across Canada under the WSER

3.0 Authorizations

There are three types of authorizations under the WSER that allow wastewater systems to temporarily not meet all or some of the WSER effluent quality standards:  transitional authorizations, temporary bypass authorizations, and authorizations to deposit un-ionized ammonia. Information on these authorizations is presented below.

3.1 Transitional authorizations

Owners or operators of a wastewater system subject to the WSER and not designed to achieve the national effluent quality standards had until June 30, 2014 to apply for a Transitional Authorization (TA). A TA establishes the conditions under which such systems may continue to operate and sets the deadline (end of 2020, 2030 or 2040) to meet the mandatory national effluent quality standards. The deadline for upgrading a given wastewater system is based on criteria set out in the WSER. Each wastewater system with a TA still must comply with the monitoring and reporting requirements of the WSER and have site-specific effluent quality standards.

A total of 65 wastewater systems in the country were issued a TA. The complete list of systems with TAs is posted on the Wastewater Systems Effluent Regulations: registry of transitional authorizations.

3.2 Temporary bypass authorizations

The owner or operator of a wastewater system may apply for a Temporary Bypass Authorization if treatment processes of the system will need to be bypassed in order to conduct maintenance of the system or make changes to it and, as a result, exceed the effluent quality standards set-out in the regulations. The bypassed effluent must also be discharged via the final discharge point in order to be eligible for a Temporary Bypass Authorization. The bypass must be designed within the constraints of technical and economic feasibility, to minimize the volume of effluent deposited and the concentration of deleterious substances in the effluent deposited.

In 2018, 20 temporary bypass authorizations were issued for 16 wastewater systems. Temporary bypasses that occurred in Québec after the equivalency agreement was in place are not included in this report.

Table 9. Temporary bypass authorizations issued in 2018.

3.3 Temporary authorization to deposit un-ionized ammonia

The owner or operator of a wastewater system that is at secondary level of treatment (i.e. meets the effluent quality standards for CBOD and SS) may apply for a temporary authorization to deposit un-ionized ammonia if the effluent from the system is acutely lethal due to the presence of un-ionized ammonia. To be accepted, the concentration of un-ionized ammonia in the receiving water at any point that is 100 m from the point of entry where the effluent is deposited must be less than or equal to 0.016 mg/L, expressed as nitrogen (N).

In 2018, there were three active temporary authorizations to deposit unionized ammonia, two of which were ongoing since their issuance in 2015, while the remaining one was issued in 2018, as presented in Table 10.

Table 10. Systems with a Temporary Authorization to Deposit Un-ionized Ammonia.

Summary

This report provides a summary of the information submitted by owners and operators of Canadian wastewater systems subject to the Wastewater Systems Effluent Regulations or an equivalency agreement for the 2018 reporting year. This report also summarizes all authorizations received under the Regulations.

All data used in this report have been published and are available on wastewater annual reports and data in multiple formats. For more information, please visit the Wastewater Systems Effluent Regulations.

4.0 Annexes

4.1. 50 largest systems in Canada, by volume of total effluent discharged

1. 830 million m³ – Station d’épuration des eaux usées Jean-R.-Marcotte, Ville de Montréal, Montréal, Québec
2. 208 million m³ – Iona Island Wastewter Treamtent Plant, Greater Vancouver Sewerage and Drainage District, Richmond, British Columbia
3. 206 million m³ – Ashbridges Bay Treatment Plant, City of Toronto, Toronto, Ontario
4. 186 million m³ – Annacis Island Wastewater Treatment Plant, Greater Vancouver Sewerage and Drainage District, Delta, British Columbia
5. 173 million m³ – G.E Booth Wastewater Treatment Plant, Regional Municipality of Peel, Mississauga, Ontario
6. 152 million m³ – Robert O. Pickard Environmental Centre, City of Ottawa, Ottawa, Ontario
7. 125 million m³ – Dufferin Creek WPCP, Regional Municipality of Durham, Pickering, Ontario
8. 117 million m³, Woodward Avenue Wastewater Treatment Plant, City of Hamilton, Hamilton, Ontario
9. 113 million m³, Centre d’épuration Rive-Sud (CERS), Ville de Longueil, Longueil, Québec
10. 112 million m³, Bonnybrook Wastewater Treatment Plant, City of Calgary, Calgary, Alberta
11. 104 million m³ – Humber Bay Treatment Plant, City of Toronto, Toronto, Ontario
12. 93 million m³ – Station d’épuration La Pinière, Ville de Laval, Laval, Québec
13. 92 million m³ – Gold Bar Wastewater Treatment Plant, EPCOR Water Sevices Inc., Edmonton, Alberta
14. 78 million m³ – Station Est d’épuration des eaux usées, Ville de Québec, Québec
15. 70 million m³ – Clarkson Wastewater Treatment Plant, Regional Municipality of Peel, Mississauga, Ontario
16. 64 million m³ - Station Ouest d’épuration des eaux usées, Ville de Québec, Québec
17. 63 million m³ - Highland Creek Treatment Plant, City of Toronto, Toronto, Ontario
18. 59 million m³ – Lou Romano Water Reclamation Plant, City of Windsor, Windsor, Ontario
19. 56 million m³ – North End Water Pollution Control Centre (NEWPCC), City of Winnipeg Water & Waste Department, Winnipeg, Manitoba
20. 52 million m³ – Usine d’épuration régionale, Ville de Gatineau, Gatineau, Québec
21. 49 million m³ – Riverhead Wastewater Treatment Facility, City of St. John’s, St. John’s, Newfoundland and Labrador
22. 42 million m³ – Greenway Pollution Control Centre, Corporation of the City of London, London, Ontario
23. 37 million m³ – Burlington Skyway Wastewater Treatment Plant, The Regional Municipality of Halton, Burlington , Ontario
24. 33 million m³ –, Halifax Wastewater Treatment Facility, Halifax Regional Water Commission, Halifax, Nova Scotia 
25. 31 million m³ - Pine Creek Wastewater Treatment Plant, City of Calgary, Calgary, Alberta
26. 31 million m³ – Lions Gate Wastewater Treatment Plant, Greater Vancouver Sewerage and Drainage District, West Vancouver, British Columbia
27. 30 million m³ – Alberta Capital Region Wastewater Commission Treatment Plant, Alberta Capital Region Wastewater Commission, Fort Saskatchewan
28. 30 million m³ – Wastewater Treatment Plant, City of Saksatoon, Saskatoon, Saskatchewan
29. 27 million m³ – Étangs aérés de Trois-Rivières, Ville de Trois-Rivières, Trois-Rivières, Québec
30. 27 million m³ – Station d’épuration de Sherbrooke, Ville de Sherbrooke, Sherbrooke, Québec
31. 26 million m³ – Wastewater Pollution Control Plant, City of Thunder Bay, Thunder Bay, Ontario
32. 26 million m³ – GMWC Wastewater Treatment Facility, Greater Moncton Wastewater Commission, Riverview, New Brunswick
33. 26 million m³ – Wastewater Facility, City of Regina, Regina, Saskatchewan
34. 25 million m³ – Lulu Island Wastewater Treatment Plant, Greater Vancouver Sewerage and Drainage District, Richmond, British Columbia
35. 25 million m³ – Kitchener Wastewater Treatment Plant, Regional Municipality of Waterloo, Kitchener, Ontario
36. 23 million m³ – Station d’épuration des eaux usées, Ville de Saint-Jean-sur-Richelieu, Saint-Jean-sur-Richelieu, Québec
37. 22 million m³ – Mid-Halton Wastewater Treatment Plant, The Regional Municipality of Halton, Oakville, Ontatio
38. 22 million m³ – Ravensview Wastewater Treatment, The Corporation of the City of Kingston, Kingston, Ontario
39. 22 million m³ – Régie d’assainissement des eaux du bassin de Laprairie, Régie d’assainissement des eaux du bassin de Laprairie, Sainte-Catherine, Québec
40. 21 million m³ - Ouvrage municipal d'assainissement des eaux usées de Sainte-Mélanie, Sainte-Mélanie, Sainte-Mélanie, Québec
41. 20 million m³ - Station d'épuration des eaux usées de Granby, Ville de Granby, Granby, Québec
42. 20 million m³ - usine d'épuration de la Seigneurie, Ville de Salaberry-de-Valleyfield, Salaberry-de-Valleyfield, Québec
43. 20 million m³ – Dartmouth Wastewater Treatment Facility, Halifax Regional Water Commission, Dartmouth, Nova Scotia
44. 20 million m³ – City of Guelph Wastewater Treatment Plant, Corporation of the City of Guelph, Guelph, Ontario
45. 19 million m³ – JAMES Pollution Control Center, City of Abbotsford, Abbotsford, British Columbia
46. 19 million m³ - Station d'épuration Sainte-Thérèse-Blainville, Régie d'asssainissement Sainte-Thérèse-Blainville, Blainville, Québec
47. 18 million m³ – South End Water Pollution Control Cnetre (SEWPCC), City of Winnipeg Water & Waste Department, Winnipeg, Manitoba
48. 18 million m³ – Wastewater Treatment Facility, The Corporation of the City of Barrie, Barrie, Ontario
49. 18 million m³ – Sudbury Wastewater Treatment Plant, City of Greater Sudbury, Sudbury, Ontario
50. 18 million m³ – Corbett Creek WPCP, Regional Municipality of Durham, Whitby, Ontario

4.2. 81 systems with a combined sewer system under the WSER

• Gold Bar Wastewater Treatment Plant, EPCOR Water Services Inc., Edmonton, Alberta
• Annacis Island Wastewater Treatment Plant, Greater Vancouver Sewerage and Drainage District, Delta, British Columbia
• Sewage Lagoon, City of Port Alberni, Port Alberni, British Columbia
• Iona Island Wastewater Treatment Plant, Greater Vancouver Sewerage and Drainage District, Richmond, British Columbia
• Clover Point Pump Station, Capital Regional District, Victoria, British Columbia
• North End Water Pollution Control Centre (NEWPCC), City of Winnipeg, Water & Waste Department, Winnipeg, Manitoba
• South End Water Pollution Control Centre (SEWPCC) , City of Winnipeg, Water & Waste Department, Winnipeg, Manitoba
• West End Water Pollution Control Centre (WEWPCC) , City of Winnipeg, Water & Waste Department, Winnipeg, Manitoba
• City of Bathurst Waste Water Treatment Plant, City of Bathurst, Bathurst, New Brunswick
• Wastewater Treatment Plant, City of Campbellton, Campbellton, New Brunswick
• Dalhousie Wastewater Treatment Plant, Town of Dalhousie, Dalhousie, New Brunswick
• St. Stephen Lagoon, Town of St. Stephen, Dufferin, New Brunswick
• Lakeside Estates, KC Properties (GP) Limited, Lakeville, New Brunswick
• Loggieville Lagoon, City of Miramichi, Miramichi, New Brunwick
• Newcastle Waste Waster Treatment Lagoon, City of Miramichi, Miramichi, New Brunswick
• Southside Waste Water Treatment Lagoon, City of Miramichi, Miramichi, New Brunswick
• GMWC Wastewater Treatment Facility, Greater Moncton Wastewater Commission, Riverview, New Brunswick
• Eastern Wastewater Treatment Facility, City of Saint John, Saint John, New Brunswick
• Lancaster Lagoon WWTP, City of Saint John, Saint John, New Brunswick
• Millidgeville WWTP, City of Saint John, Saint John, New Brunswick
• Riverhead Wastewater Treatment Facility, City of St. John’s, St. John’s, Newfoundland and Labrador
• Bridgewater Wastewater Treatment Plant, Town of Bridgewater, Bridgewater, Nova Scotia
• Dartmouth Wastewater Treatment Facility, Halifax Regional Water Commission, Dartmouth, Nova Scotia
• Dominion/Bridgeport WWTP, Cape Breton Regional, Dominion, Nova Scotia
• Donkin Sewer Shed – D1, Cape Breton Regional, Donkin, Nova Scotia
• Westmount/Coxheath – C1, Cape Breton Regional, Edwardsville, Nova Scotia
• Westmount/Coxheath – C3, Cape Breton Regional, Edwardsville, Nova Scotia
• Tower Road Lagoon, Cape Breton Regional, Glace Bay, Nova Scotia
• Glace Bay – GB2, Cape Breton, Glace Bay, Nova Scotia
• Glace Bay – GB8, Cape Breton, Glace Bay, Nova Scotia
• Halifax Wastewater Treatment Facility, Halifax Regional Water Commission, Halifax, Nova Scotia
• Sewage Treatment Plant, Town of Mahone Bay, Mahone Bay, Nova Scotia
• New Victoria Sewer Shed, Cape Breton Regional, New Victoria, Nova Scotia
• New Waterford – NW1, Cape Breton Regional, New Waterford, Nova Scotia
• Town of port Hawkesbury Wastewater Plant, Town of Port Hawkesbury, Port Hawkesbury, Nova Scotia
• Battery Point Treatment Plant, Cape Breton Regional, Sydney, Nova Scotia
• Meadowbrook Lagoon, Cape Breton Regional, Sydney Mines, Nova Scotia
• North Sydney, Sydney Mines, Florence (North Division) – ND2, Cape Breton Regional, Sydney Mines, Nova Scotia
• Town of Yarmouth Wastewater Treatment Plant, Municipality of the Town of Yarmouth, Yarmouth, Nova Scotia
• Alexandria Sewage Works, The Corporation of the Township of North Glengarry, Alexandria, Ontario
• Amherstburg Wastewater Treatment Plant, Town of Amhersburg, Amherstburg, Ontario
• Beleville Wastewater Treatment Facility, The Corporation of the City of Belleville, Belleville, Ontario
• The of Clinton Sewage Treatment Plant, Corporation of the Municipality of Central Huron, Clinton, Ontario
• Cornwall Wastewater Treatment Plant, Corporation of the City of Cornwall, Cornwall, Ontario
• Crystal Beach Wastewater Treatment Plant, Regional Municipality of Niagara, Crystal Beach, Ontario
• Foleyet Wastewater Treatment Lagoon, Foleyet Local Services Board, Foleyet, Ontario
• Fort Erie Wastewater Treatment Plant, Regional Municipality of Niagara, Fort Erie, Ontario
• Goderich Water Pollution Control Plant, The Corporation of the Town of Goderich, Goderich, Ontario
• Baker Road Wastewater Treatment Plant, Regional Municipality of Niagara, Grimsby, Ontario
• Woodward Avenue Wastewater Treatment Plant, City of Hamilton, Hamilton, Ontario
• Hawkesbury Wastewater Plant, Corporation of the Town of Hawkesbury, Hawkesbury, Ontario
• Iroquois Falls Sewage Treatment Plant, Corporation of the Town of Iroquois Falls, Iroquois Falls, Ontario
• Kenora Area Wastewater Facility, City of Kenora, Kenora, Ontario
• Ravensview Wastewater Treatment, The Corporation of the City of Kingston, Kingston, Ontario
• Leamington Pollution Control Centre, Corporation of the Municipality of Leamington, Leamington, Ontario
• Greenway Pollution Control Centre, Corporation of the City of London, London, Ontario
• Manitouwadge Wastewater Lagoons, The Corporation of the Township of Manitouwadge, Manitouwadge, Ontario
• Matheson Wastewater Treatment Plant & Collection System, Township of Black Ricer-Matheson, Matheson, Ontario
• Niagara Falls Wastewater Treatment Plant, Regional Municipality of Niagara, Niagara Falls, Ontario
• Niagara-on-the-Lake Lagoon, Regional Municipality of Niagara, Niagara Falls, Ontario
• Robert O. Pickard Environmental Centre, City of Ottawa, Ottawa, Ontario
• Owen Sound WPCP, City of Owen Sound, Owen Sound, Ontario
• Parry Sound WWTP, The Corporation of the Town of Parry Sound, Parry Sound, Ontario
• Port Colborne Wastewater Treatment Plant, Regional Municipality of Niagara, Port Colborne, Ontario
• Prescott Wastewater Treatment Plant, Separated Town of Prescott, Prescott, Ontario
• Water Pollution Control Centre, City of Sarnia, Sarnia, Ontario
• Smiths Falls Water Pollution Control Plant, Corporation Town of Smiths Falls, Smiths Falls, Ontario
• Port Dalhousie Wastewater Treatment Plant, Regional Municipality of Niagara, St. Catherines, Ontario
• Port Weller Wastewater Treatment Plant, Regional Municipality of Niagara, St. Catherines, Ontario
• Stevensville/Douglastown Lagoon, Regional Municipality of Niagara, Stevensville, Ontario
• Temagami North Wastewater Treatment Lagoon, Municipality of Temagami, Temagami, Ontario
• Water Pollution Control Plant, City of Thunder Bay, Thunder Bay, Ontario
• Ashbridges Bay Treatment Plant, City of Toronto, Toronto, Ontario
• Humber Treatment Plant, City of Toronto, Toronto, Ontario
• North Toronto Treatment Plant, City of Toronto, Toronto, Ontario
• Welland Wastewater Treatment Plant, Regional Municipality of Niagara, Welland, Ontario
• Little River Pollution Control Plant 1, City of Windsor, Windsor, Ontario
• Lou Romano Water Reclamation Plant, City of Windsor, Windsor, Ontario
• Wingham STP, The Corporation of the Township of North Huron, Wingham, Ontario
• MDN, usine de traitement des eaux usées Valcartier, Department of National Defence, Courcelette, Québec
• Wastewater Facility, City of Regina, Regina, Saskatchewan

4.3. Supplementary monitoring data

Supplementary Data Table 1. Number of systems that meet the WSER limit of 25 mg/L for CBOD by province and treatment type in 2018.

Supplementary Data Table 2. Number of systems that meet the WSER limit of 25 mg/L for suspended solids by province and treatment type in 2018.

Supplementary Data Table 3. Acute lethality test results by province and treatment type in 2018 under the WSER.