The Environmental Impacts of Sewage Treatment Plant Effluents
Contents |
Introduction
Sewage treatment is a largely invisible basic service that most Ontarians spend little time worrying about, confident that proper sewage treatment infrastructure is in place and well managed, and that inadequate sewage treatment is primarily a problem of distant developing countries. Yet poor effluent quality from municipal sewage treatment plants (STPs) is one of the root causes of water pollution in Ontario’s lakes and rivers.
The International Joint Commission identified 17 Ontario Great Lakes locations as Areas of Concern in 1985, and at 10 of these 17 sites, municipal wastewater pollution was identified as a major problem. Since then, improvements have certainly been made at many Ontario STPs, but not nearly enough to compensate for population growth and the general aging and deterioration of facilities. Some concerned citizens are observing problems: in 2002/2003 the ECO received three separate applications under the Environmental Bill of Rights, all related to water quality problems and STPs. (See pages 155-158 regarding an EBR application on the Ashbridges Bay STP in Toronto)
The ECO has also been monitoring the issue from the perspective of the Canada-Ontario Agreement on the Great Lakes (COA). For example, the ECO noted in our 1999/2000 annual report that although the 1994 COA had set a target of upgrading eight Ontario STPs by the year 2000, only one plant (in Espanola) had been fully upgraded by that deadline. (The COA was renewed in 2002, and is described on pages 73-76.)
How much STP effluent is discharged to Ontario waterways?
Over 450 municipal sewage treatment plants were operating in Ontario in 1998. Their combined treatment capacity was 6.7 million cubic metres per day, with Lake Ontario getting the lion’s share of effluents — receiving 38 per cent of the overall provincial STP discharge capacity in 1998, for instance. The Ottawa River received the next largest discharge volume, almost 9 per cent of the provincial total capacity. Many other waterways connected to the Great Lakes receive significant volumes of municipal STP discharges, especially Redhill Creek, the Grand River, the Thames River, the St. Lawrence River and the Detroit River.
What is in municipal sewage?
Municipal sewage is a complex mixture of liquid wastes flushed down sewers by residential, commercial, institutional and industrial sources. It contains human wastes, of course, and bathroom tissues, which arrive at the treatment facility largely in the form of dissolved organic matter and suspended fibrous material, and which contribute large loadings of nitrogen, phosphorus and pathogens. These are the substances that municipal STPs are chiefly designed to treat.
Municipal STPs also receive many other types of wastes, however, which are not as responsive to treatment — some are only partially degraded during sewage treatment, some tend to accumulate in sewage sludges, and other wastes pass unaffected into the final effluent and the receiving waterway. For example, commercial and industrial facilities discharge a wide variety of liquid wastes to sewers, often containing persistent organic pollutants, metals, and organic materials that resist decomposition. Residential and industrial cleaning agents and miscellaneous grit and plastic debris are also common constituents of municipal sewage. Human wastes contribute trace quantities of hormones and pharmaceuticals to the sewage mixture, some of which may have the ability to disrupt the functioning of animal and human endocrine systems.
| Parameters that may be Measured in STP Effluent |
|---|
Biochemical oxygen demand (BOD)
Total suspended solids (TSS)
Total phosphorus (TP)
E. coli
Ammonia
|
What is the impact on waterways?
According to Environment Canada, the treated effluents of municipal STPs are a leading source of the biochemical oxygen demand (BOD), total suspended solids (TSS), nutrients, organic chemicals and metals that are discharged into Canadian waters. Persistent organic pollutants, bacteria and other types of pathogens are also commonly associated with STP effluents.
The impacts of STP effluent on water quality and ecosystems can vary greatly, depending on factors such as the volumes and quality of effluent being discharged and the ability of the receiving waterway to dilute and assimilate contaminants. In the approval process for STP discharges, regulating agencies usually consider the assimilative capacity of watercourses and variable flow rates. Other things being equal, larger lakes and rivers can dilute more effluent than smaller ones, and fast-flowing, well-oxygenated rivers have a greater assimilative capacity than slow-moving rivers. Where municipal STPs discharge into protected bays or harbours (such as Toronto’s Ashbridges Bay), concentrated effluents may have stronger local impacts on fish habitat or nearby bathing beaches.
Waterways that receive a high proportion of effluent from primary treatment plants (see Factors that affect sewage treatment plant quality) may be more seriously impacted than waterways that receive secondary treatment effluent. For example, in 1991, Lake Superior, the Ottawa River and the St. Lawrence River each received over 80 per cent of their Ontario-source STP volume from plants providing only primary treatment, according to MOE.
According to Environment Canada, municipal STPs contribute much higher loadings
of phosphorus and nitrogen to Canadian waterways than industries that discharge
directly into lakes or rivers. Increases in phosphorus levels can lead to long-term,
fundamental changes in the structure and species mix of aquatic communities. One
of the first results can be the proliferation of algae and other aquatic plants. As these
plants decay and die, oxygen in the water can be used up, and fish kills can result.
The ECO noted in our 2001/2002 annual report that a number of lakes and rivers in southwestern Ontario are exhibiting elevated levels of nitrogen and phosphorus. Run-off from agricultural land is thought to be the major contributing factor, but municipal STP effluents are also contributing to these loadings. Phosphorus loadings, especially to Lake Erie, have been a long-standing concern. Bi-national controls in the 1970s led to reduced phosphorus loadings from STP effluents, and great improvements in the health of Lake Erie. But the concentrations of phosphorus in Lake Erie continue to exceed guidelines, and the lake is once again in trouble. STP effluents contribute not only to overall long-term loadings of pollutants; they can also be acutely toxic to fish and other aquatic organisms living near the discharge point. “Acutely toxic” means that test organisms cannot survive for more than hours or days when exposed to the effluent. According to a recent Environment Canada overview, under estimated average conditions, some municipal wastewater discharges could be toxic for 10–20 kilometres downstream. Plants and animals that live on the bottom of lakes and rivers may be disrupted up to 20–100 kilometres from STP discharge points.
Acute toxicity is most often caused by high levels of ammonia and chlorine or heavy metals and organic contaminants. Ammonia (a product of nitrogen metabolism) appears to be a particular problem; municipal STPs are the leading quantifiable source of ammonia entering waterways in Canada. Many municipal STPs add chlorine to their final effluent during summer months to kill bacteria, viruses and other pathogens, and chlorine is also acutely toxic to fish. Moreover, the combination of chlorine and ammonia in water will form chloramines, which are highly toxic to fish and other organisms. Only a very small percentage of STPs address this problem by de-chlorinating their effluent before discharging it. However, a number of Ontario STPs (including Windsor, Sarnia, Barrie, Georgetown, London and Peterborough) have moved to ultraviolet disinfection of their final effluent, which eliminates the chlorine toxicity problem.
What is the condition of Ontario STPs?
It is difficult to present an up-to-date overview of Ontario’s municipal STPs because the Ministry of the Environment last published a comprehensive summary in 1993, based on 1991 data. In 2001, a consulting firm provided some updates after evaluating 1998 MOE data for a background paper commissioned by the Walkerton Inquiry.
There are many ways to evaluate the condition and performance of STPs. One can consider the loadings of pollutants released, the toxicity of effluents, the amount of sewage that bypasses treatment, the number of plants that are operating at or over capacity, and the percentage of facilities with secondary or tertiary treatment. Evaluating all these indicators can provide a rounded picture. Available public data indicate that the effluents of Ontario STPs are putting very serious pressure on the environmental quality of Ontario waterways, and that a large proportion of STPs need upgrades.
Range of treatment types
In 1991, 72 per cent of Ontario’s sewage volume received secondary treatment, 4 per cent received tertiary treatment, and 18 per cent of the volume (28 facilities) received primary treatment. This situation had improved somewhat by 1998; the number of primary treatment plants had dropped from 28 to 23 plants. But in 1998, large population centers like Windsor, Thunder Bay, Sarnia and Cornwall all still had primary treatment with continuous phosphorus removal; Sault Ste Marie had primary treatment only; and Timmins had primary treatment with de-chlorination. Most recently, Thunder Bay has started construction of a secondary treatment plant, and Sarnia’s was upgraded to secondary treatment in 1999. MOE has informed the ECO that there are 15 primary STPs operating in Ontario in 2003, and the ministry has established priorities for updating the certificates of approval (Cs of A) for these plants.
Since primary sewage treatment plants provide only mechanical screening and settling of solids, their effluent quality is relatively poor. Thus, the 28 primary plants that operated in Ontario in 1991 contributed a disproportionate amount of pollutant loadings to Ontario waterways. Although they treated only 18 per cent of the total sewage flow, they contributed 47 per cent of the total BOD loadings, 39 per cent of the TSS loadings and 28 per cent of the TP loadings. Moreover, primary treatment removes virtually no ammonia, which is toxic to fish.
Loadings
The treated effluents of municipal STPs add significant loadings of many kinds of pollutants to Ontario waterways, some of which are measured in tonnes per day. According to MOE’s analysis of 1991 data, Ontario waterways received a total of 112 tonnes per day of BOD, 104 tonnes per day of TSS, and 4.1 tonnes per day of total phosporus (TP) from the effluent of Ontario STPs. Over the four years from 1987 to 1991, a period of strong economic growth, loadings to Ontario waterways increased significantly. The overall effluent volume of Ontario STPs increased by 12 per cent, the overall loading of BOD increased by 25 per cent, and the overall loading of TSS increased by 14 per cent. The only improvement in that four-year period was in overall loading of TP, which decreased by 11 per cent. Unfortunately, MOE has not published more recent summary data, making it impossible to assess whether STP pollutant loadings have improved or deteriorated over time. Ontario decision-makers are missing another important analytical tool as well: MOE has not published an estimate of the pollutant loadings from various types of dischargers to Ontario waterways. This means that MOE and the public cannot easily evaluate the relative impacts of STP effluents compared to industrial dischargers or non-point sources. The ECO first raised this point in our 1997 annual report.
Toxicity of Ontario STP effluents
Major industries that discharge to Ontario waters must test effluents for acute toxicity using indicator species such as trout and water fleas (Daphnia magna), and must report results. MOE issues Director’s or Provincial Officer’s Orders when industrial effluents fail such toxicity tests. But municipal STPs are generally not required to carry out such testing.
An early 1990s MOE study indicated that a significant proportion of Ontario STPs do produce acutely toxic effluents. This is not surprising, since Ontario STPs discharge approximately 55 tonnes of ammonia and 2.5 tonnes of chlorine daily into Ontario waterways. Ontario’s top seven sources of ammonia releases to water were all municipal STPs, according to Environment Canada’s analysis of 1999 data, with the two largest sources Canada-wide being the Ashbridges Bay STP in Toronto and Ottawa-Carleton’s STP.
MOE’s current position is that new and expanding STPs will need to control ammonia and chlorine levels in final effluents so that they are non-acutely lethal to aquatic life, while existing facilities are exempt. But MOE’s interpretation of this point is variable: for example, MOE allowed the Lakeview STP, serving 700,000 people in Mississauga, to expand its capacity by 17 per cent in 2002, without imposing new requirements to control acute toxicity of final effluents. MOE informed the ECO in July 2003 that the ministry’s policy on acute lethality is under review, to be completed in 2004.
Sewage bypassing treatment
Another way of evaluating STP performance is to look at how much sewage bypasses treatment plants during wet weather. Combined sewer overflows (CSOs) upstream in the sewer systems and sewage bypasses downstream at the treatment plants occur because sewers in older urban areas receive both sanitary sewage and storm water. During storms or snow melts, the combined sewage volumes surge, and must be temporarily redirected into waterways to prevent flooding basements or overloading treatment plant capacities. CSO discharge points are very widespread in older urban areas.
For example, the City of Toronto has 71 CSO discharge points into local rivers and Lake Ontario, with overflow events estimated to occur dozens of times a year. The total volumes of untreated sewage discharged from CSOs are not summarized nor published on a province-wide basis by MOE. However, since 1997, MOE has required municipalities with combined sewer systems to develop control plans, and as a consequence, municipalities are beginning to evaluate and quantify their CSO discharges. Thus, Hamilton, for example, has been able to estimate that the city’s CSOs discharge an average of 4.5 million cubic metres into local waterways during the April-October period of each year.
Sewage bypasses are also common. For example, Toronto’s Ashbridges Bay STP redirected sewage to bypass secondary treatment on 12 occasions in 2001. March and April are generally the peak months for sewage bypasses. Sewage treatment plants are allowed to bypass raw sewage only in emergencies — to protect basements from flooding, to prevent damage to equipment at treatment works or pumping facilities, or to prevent solids from being washed out in the treatment works. In some cases, sewage will bypass secondary treatment, but will at least receive primary treatment. In other cases, sewage will bypass both secondary and primary treatment, which means that raw sewage, diluted by storm water, is entering waterways.
According to MOE, 75 municipal STPs reported bypasses in 1991. In total, 2.2 million cubic metres of sewage bypassed primary treatment, and 9.6 million cubic metres bypassed secondary treatment. In 1998, 43 municipal STPs reported bypass events; in total, 3.9 million cubic metres of sewage bypassed primary treatment and 9.2 million cubic metres bypassed secondary treatment. Since MOE has not published summary data on sewage bypass volumes for other recent years, it is hard to draw strong conclusions about sewage bypass trends over time.
Sewage bypasses and CSOs present a special challenge for treatment plant engineers and managers, because they represent extreme surges of flow occurring over just a few days or even hours. Engineers must either find ways to capture and treat these flows (which can be up to 50 times the volumes observed in fully separated sewer systems), or they must redesign urban areas to reduce these occasional surges of stormwater. Both approaches have advocates, and both require considerable commitment and resources. One long-term incremental solution is to replace old combined sewers gradually with separate sewers for storm water and sewage, as part of routine sewer maintenance and upgrade programs. Climate change projections for southern Ontario indicate that over the next 40 years, precipitation will increase, be more variable, and exhibit more variable peak flows. This will tend to exacerbate the problems of CSOs and sewage bypasses.
Number of plants operating near capacity
Many Ontario STPs are being operated near the upper limit of their design capacity or are already overloaded. In 1995, 20 per cent of Ontario STPs were already in need of expansion to meet existing flows; by 2005, over 50 per cent of STPs will need expansion, according to a 1996 internal estimate by MOE. The ministry document estimated that $595 million would be needed to cover the existing (1995) shortfall between actual sewage flows and STP design capacity. A further $1.28 billion would be needed over the period 1995–2000 to rehabilitate existing plants and respond to growth needs. Finally, a further $1.58 billion would be needed over the period 2000-2005 to rehabilitate existing plants and respond to growth needs. As a separate cost, the same MOE document also estimated that $745 million would be needed to upgrade all primary sewage treatment plants in Ontario to secondary treatment.
In total, Ontario STPs would need $4.2 billion in spending over the period 1995–2005 to cover repairs and rehabilitation, to accommodate existing needs and expected growth, and to upgrade primary plants to secondary treatment. This would require province-wide expenditures of approximately $400 million per year dedicated to sewage treatment infrastructure, over 10 years.
How are Ontario STPs regulated?
MOE has prime responsibility for regulating the construction and operation of Ontario STPs. The ministry issues certificates of approval under the Ontario Water Resources Act (OWRA) to facility owners. Once issued, Cs of A have no automatic expiry dates, but MOE can revise Cs of A and make them more stringent on a case-by-case basis – usually as part of a facility expansion. MOE has not conducted a province-wide review of Cs of A to tighten the requirements for STPs. However, Ontario residents do have the right under the Environmental Bill of Rights to request reviews of specific Cs of A, and, in fact, one such review is currently under way for Hamilton’s STP.
By long-standing engineering conventions, the regulatory effluent limits for STPs tend to be parameters that mainly reflect the hydraulic performance of the facility. It is much less common to see regulated limits that directly reflect the environmental or biological performance of facilities. For example, although the effectiveness of secondary treatment depends completely on the health of the microbial community and on adequate aeration levels, Ontario facilities are not required to report on these parameters. MOE requires operators to monitor flows as well as BOD (biological oxygen demand), suspended solids and total phosphorus at nearly all plants, and nitrogen and chlorine as necessary at some plants. MOE’s position is that these parameters reflect both the hydraulic and the biological performance of the facilities. Cs of A issued before 1985 give design or operation objectives, but not compliance limits. Since 1985, MOE has issued Cs of A that include compliance limits to over 200 municipal STPs. MOE measures the performance of the remaining (roughly 250 older) STPs against several MOE policies, which specify STP effluent guidelines for BOD, TSS and TP. Generally, the facilities that have compliance limits written directly into their Cs of A face more stringent limits than those which are assessed against the policy guidelines.
Because many municipal STPs were constructed in the 1970s, their Cs of A are unlikely to reflect current environmental priorities. MOE has acknowledged that outdated Cs of A are a systemic problem, and in 2000 the ministry promised the Provincial Auditor there would be improvements on this front. In May 2002, MOE proposed protocols for updating four kinds of Cs of A, including Cs of A for sewage works (see Registry posting PA02E0007). MOE considered comments received through the Registry posting, and began implementing most of the protocols in 2002. MOE has delayed posting a decision notice until all four protocols have been updated. However, MOE has informed the ECO that as of May 2003, the ministry does not have up-to- date information regarding the overall percentage of sewage works Cs of A that require updating.
Compliance, inspection and enforcement
About 240 municipal STPs in Ontario are operated by the Ontario Clean Water Agency (OCWA), which is a provincial agency established in 1993 to take over certain functions formerly handled by MOE. Another approximately 200 STPs are operated either directly by municipalities or by their contractors (1998 data). The operators of STPs are responsible for sampling and analysing their final effluent, and for submitting the results monthly to MOE regional offices. Operators must follow sampling procedures set out by MOE (Procedures F-10 and F-10-1), unless MOE sets out more or less stringent requirements on a case-by-case basis. Samples must be taken at least monthly, and must be analysed, at a minimum, for BOD, TSS, ammonia plus ammonium nitrogen and total phosphorus. MOE has informed the ECO that 155 municipal STPs must also monitor for one or more of the following parameters: ammonia, bacteria and residual chlorine. Typically, larger facilities will sample four days a month, and will make composite samples over a 24-hour period. To check for compliance, MOE district offices assess the self-reported data against the ministry’s effluent guidelines, or against any effluent limits that may be set out in a C of A. MOE collects effluent samples as part of periodic inspections carried out at least every four years. If the samples collected during an inspection yield analytical results that differ greatly from performance data typically supplied by the authority, the district office is alerted to a potential need to scrutinize the data more thoroughly. While most operators submit valid data sets, there have been cases where fraudulent data were submitted. In 2000, MOE laid numerous charges against a former supervisor of the Brockville STP, including charges of providing false or misleading information on plant performance. At the trial, testimony indicated that operators and technicians were instructed to re-sample or do selective sampling of the treated sewage to sanitize readings. Witnesses testified that phosphorus samples were taken during low flow periods late Sunday nights to bring results down to acceptable levels, and that high test results were omitted from averages.
MOE regional offices also pass along copies of the data to the ministry’s Environmental Monitoring and Reporting Branch. This central branch then summarizes the data into an annual Environmental Compliance Report. But it appears there are not enough data at the provincial level to allow ministry staff to check overall trends in compliance. A report prepared for the Walkerton Inquiry found that for the year 1998, MOE had insufficient data to assess compliance for almost 60 per cent of STP facilities.
Reporting on compliance
MOE summarizes the performance of municipal STPs in annual Environmental Compliance Reports on the ministry’s Web site. The format and content of these reports deteriorated between 1997 and 1999, as important information was stripped away. In 1997, the compliance report listed:
- in a single printable document, all non-compliant facilities.
- for each facility, each parameter that was exceeded (ammonia, phosphorus, etc.).
- the allowable limit for that parameter as set out in the C of A.
- the time period and frequency (date or month) of the exceedances.
- repeat offenders, marked with an asterisk.
Since 1999, the annual compliance reports have listed only one single parameter that was exceeded for each non-compliant facility. As a result, the public no longer knows which facilities exceed limits for multiple parameters, or which ones are non-compliant two years running. Furthermore, the public can no longer compare exceedances with allowable limits, or check how frequently exceedances occurred within a given year.
Compliance trends
MOE’s Business Plan for 1997/1998 set a target of 100 per cent compliance by municipal STPs. The following year, MOE’s Business Plan reported that “we ensured that the current rates of water quality compliance were being maintained for municipal sewage works.” However, the ministry has not published a summary of the actual rate of compliance by municipal STPs since 1993. Among other things, the 1993 summary showed that secondary and tertiary treatment plants had a much better compliance rate than primary plants, even though primary plants are judged against more lenient guidelines. Primary plants had a 39 per cent compliance rate.
Primary Plants:
| Year | # of Plants | Pass | Fail | % Pass | % Fail |
|---|---|---|---|---|---|
| 1991 | 28 | 11 | 17 | 39 | 61 |
| 2001 | 16 | 9 | 7 | 60 | 40 |
Secondary Plants:
| Year | # of Plants | Pass | Fail | % Pass | % Fail |
|---|---|---|---|---|---|
| 1991 | 184 | 155 | 29 | 84 | 16 |
| 2001 | 177 | 133 | 44 | 75 | 25 |
Despite an apparent problem with non-compliance at many municipal STPs, MOE very rarely prosecutes STP operators. And although MOE also has the power to issue Orders requiring STP operators to purchase new equipment or improve monitoring, the ministry appears to prefer voluntary abatement programs for the STP sector. A scan of MOE’s 2001 Environmental Compliance Report indicates that in responding to water quality compliance problems, the ministry issued twice as many Orders to the industrial sector as to the municipal STP sector. MOE attributes the difference in the number of Orders to the fact that the industrial sector is covered by MISA regulations, while municipal STPs are covered only by certificates of approval.
Inspections
MOE inspects municipal STPs periodically. The ministry’s Business Plans for the last several years have included specific targets for inspection of municipal STPs:
- 120 plants to be inspected for the year 2000/2001
- 155 plants to be inspected for the year 2001/2002
- 115 plants to be inspected for the year 2002/2003
However, MOE does not publish summaries of its inspections of STPs, so there is no public record of how many STPs are actually inspected in a given year, nor the outcome of inspections. In contrast, after the Walkerton tragedy, MOE began inspecting all municipal drinking water plants annually in 2000, and has published summaries itemizing reasons why each drinking water plant failed inspection.
Why have Ontario STPs been neglected?
The public believed the job was finished
In the 1970s the Ontario government, together with municipalities and the federal government, developed an aggressive program to upgrade STPs and install phosphorus removal systems to control eutrophication problems in the Great Lakes, especially Lake Erie. The investments of the 1970s in municipal and industrial wastewater control achieved excellent results in nutrient management, and the recovery of Lake Erie in particular was widely hailed as an environmental success story. The less glamorous tasks of maintaining and repairing this expensive infrastructure has a much lower public profile, in part because the facilities are physically hidden from the population, and because the impacts of gradual infrastructure deterioration are felt by ecosystems, rather than directly by taxpayers. Other types of public infrastructure are under much closer public scrutiny — Ontario’s highway system being but one example — and therefore have higher priority maintenance programs. For example, under the Ministry of Transportation’s capital construction program, roughly 33 per cent of Ontario highways are rehabilitated every five years, allowing the complete refurbishing of the entire highway network every 15 years.
Other environmental priorities came up
Once the eutrophication of the lower Great Lakes had been addressed, the attention of scientists, regulators and the public shifted to other emerging environmental concerns, such as toxic substances and acid rain.
Control strategies were derailed
In 1986, MOE announced a program that promised to address effluents from municipal STPs — the Municipal-Industrial Strategy for Abatement (MISA). Among other goals, MISA targeted over 400 municipal STPs and also proposed a sewer use control program, to be enforced by municipalities, that would deal with the effluents of approximately 12,000 industrial plants hooked up to municipal sewers. Because of MISA’s focus on persistant toxic substances, it staged the introduction of regulations to deal one by one with nine industrial sectors discharging directly to waterways, with municipal STPs last on the timetable. But by 1991, Ontario was in the grip of an economic recession, so the municipal side of MISA was quietly put on the backburner. The one clear benefit that arose from this effort was that MOE published several studies and overviews of Ontario STP performance.
Municipalities and their consultants have long been anticipating that STP treatment standards will become more stringent in Ontario. Environment Canada has heightened these expectations by adding several substances found in STP effluents (ammonia and inorganic chloramines) to the list of CEPA-toxic substances. But MOE, the key regulating agency in this instance, remains silent on the issue.
Funding programs in flux
When the province established the Ontario Clean Water Agency in 1993 as a Crown corporation to “finance, build and operate water and sewage facilities throughout the province and provide service and advice to communities on a cost recovery basis,” it became, in effect, OCWA’s job to help municipalities upgrade their STPs. Then in May 1997, the province passed the Municipal Water and Sewage Transfer Act, which eliminated OCWA’s ownership and financier roles and transferred facilities previously owned by OCWA to municipalities. OCWA also no longer provides loans to municipalities for capital infrastructure.
In August of 1997, the province established a $200 million Provincial Water Protection Fund (PWPF) to help municipalities with both drinking water and sewage treatment projects. Most of this funding was paid out by the end of March 2000, with recipient municipalities paying a portion of project costs. In 1998, grants from the PWPF were announced for approximately $75 million of provincial funding toward sewage infrastructure projects. This was significantly less than MOE’s 1996 estimate of province-wide sewage infrastructure needs of $400 million per year over 10 years.
In December 1999, the province created the Ontario Superbuild Corporation (an agency of the Ministry of Finance) to address a wide range of infrastructure needs, including water and sewage systems. Part of Superbuild’s mandate is to achieve capital investments totaling $20 billion over a five-year period through provincial, broader public sector and private sector partnerships. Funding is certainly available for sewage infrastructure: Superbuild’s Web site lists approximately 90 sewage projects approved since spring 1999, including upgrades for Sarnia and Thunder Bay STPs from primary to secondary treatment. But the Web site does not include any analyses of how the Superbuild’s funds have been allocated among the broad eligible categories, which also include transportation, sports, culture, tourism and environment. Nor is it possible to judge how the approved sewage projects compare to environmental needs identified by MOE, or how environmental needs were ranked against growth and development needs.
The public is unaware of problems
The public cannot use the Environmental Registry as a window to monitor proposed changes to municipal STPs, because such projects are excepted from EBR notice, comment and appeal requirements. Many public sector projects such as sewage and water works are regulated under the Environmental Assessment Act (EAA), so the EAA public consultation rules apply instead of the EBR rules. However, the ECO raised concerns in our 2001/2002 annual report that the EAA rules do not provide the kind of transparency that the EBR affords.
As well, MOE has provided very little in the way of public reporting on the state of Ontario STP effluents over the last decade. MOE’s Environmental Compliance Reports have deteriorated to the point where they are of very little value to the interested public. Thus, there has been little public pressure for STP improvements. Mississauga Mayor Hazel McCallion summed the situation up succinctly in February 2003: “The [federal] government was listening to the public and the public wasn’t clamouring for sewage treatment plants.”
MOE has also failed to produce overviews of surface water quality trends, as noted in ECO’s 2001/2002 annual report. As a result, we have a very deficient warning system for the health of Ontario waterways. In contrast, MOE provides a high quality of public reporting on ambient air quality trends, and has also begun to report on air emissions of major industrial sectors.
Similarly, there appears to have been little internal evaluation within MOE of the impact of STP effluents, or big-picture, long-term trends. A 1996 staff document noted this problem: “Although information exists on STP effluent treatment levels, bypasses and compliance with guidelines and Cs of A, there has been insufficient analysis of the specific relationship between contaminant levels in STP effluent and environmental problems, e.g., beach closings, fish kills and impaired uses. In other words, even though an environmental problem may exist, it is not clear, on an aggregate basis, to what extent that problem may be attributed to contaminant levels in STP effluent.”
The “sticker shock” for decision-makers
This may be the primary factor that has delayed action. Although a 1996 internal MOE report outlined the need for major upgrades at Ontario STPs, the estimated $4.2 billion price tag ran counter to the government cost-cutting exercise under way at that time, and the report was shelved. Unfortunately, this has been another instance where decision-makers have been preoccupied with the “near and now” to the detriment of the environment.
ECO Comment
A new approach is needed
Sooner or later, we will need to upgrade Ontario’s aging STPs, forced either by international pressure, or by large-scale ecosystem declines. It would be far preferable to begin the job sooner, because it will need a long-term, incremental approach. All levels of government will need to be involved in the solution. Clear priorities will need to be set, and a new approach to financing will undoubtedly be required. One promising sign has been the recent enactment of the Sustainable Water and Sewage Systems Act, which emphasizes a full-cost accounting approach for financing. An increased focus on optimizing STP performance may be very cost-effective in the short term, and this in turn will require improved monitoring and reporting on STP performance. But the first step — a step that MOE can take now — should be a clear, unvarnished accounting of the environmental impacts of STP effluents on receiving lakes and rivers. (For ministry comments, see pages 204-205.)
| Recommendation 3:
The ECO recommends that the Ministry of the Environment put in place a plan to upgrade Ontario’s aging municipal sewage treatment plants to modern environmental standards. A first step should be to document and report on the quality of STP discharges to Ontario’s receiving waters. |
| This is an article from the 2002/03 Annual Report to the Legislature from the Environmental Commissioner of Ontario. |
Citing This Article
Environmental Commissioner of Ontario. 2003. "The Environmental Impacts of Sewage Treatment Plant Effluents." Thinking Beyond the Near and Now, ECO Annual Report, 2002-03. Toronto, ON : Environmental Commissioner of Ontario. 35-49.
