Water Legislation and Substance/Quality Database Canadian Water and Wastewater Association

Frequently Asked Questions
Municipal Wastewater Services
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What happens to waste after I flush my toilet?
The wastes leave your home through a collection system that takes the wastes to the local wastewater treatment facility. The facility type may vary from municipality to municipality depending on the population served and the age of the community.

Who is responsible for the infrastructure, and operates and maintains the facilities?
The collection and treatment systems are usually owned and operated by a municipality. The municipality will be responsible for maintaining the infrastructure and operating the facility. In large regional governments, the regional government and local municipalities may share in the costs and operations of the system. There are some systems in Canada that have been privatised and therefore are operated by a private company.

Who is responsible for storm sewers and where do they go?
Storm sewers are part of a municipality’s collection system.. Storm sewers are the responsibility of the municipality. The materials put into storm sewers go directly to the nearest receiving stream. It is too expensive to treat large volumes of water at the wastewater treatment facility that may be largely rain water. However, there are still contaminants entering the environment through these systems.

What is a CSO?
A CSO, or combined sewer overflow, is usually found in older, larger cities before separating sewers was practised. The sewers usually convey storm water to a receiving body of water, but when excessive flows occur, greater than the hydraulic capacity of the system, sewage overflows into these pipes and mixes with the storm water. The mixture with untreated sewage is released to the environment.

Are homeowners regulated as to what they put down the drain?
There are no specific regulations but homeowners should be aware that anything that goes into the toilet or down the drain that causes a problem may be traced back to the specific home. Any damage done between the house and street is the responsibility of the homeowner.

Do industries and institutions discharge to the municipal sewer system?
Yes, industries and institutions discharge to the municipal sewer system. Some large industries or institutions may have their own treatment facilities but they are required to meet certain criteria and obtain an operating certificate, licence or permit.

What types of treatment are there for domestic sewage?
The conventional levels of treatment are referred to as primary, secondary, and tertiary (or advanced secondary). Primary may include a preliminary step that simply removes large objects by screening. Primary usually includes a screening and settling process where large objects and solid materials are allowed to settle by physical means to the tank bottom. These are removed and land filled.

Secondary treatment is a biological process that includes an aerated and unaerated stage which assist different types of microbes to digest the solid organic waste materials. Other chemicals may be added to the process train for removal of phosphorus. New technologies may be added in various permutations and combinations to enhance treatment, removing specific contaminants. These latter additions suggest an advanced secondary or tertiary treatment.

Does this treatment remove everything?
Historically, sewage treatment was designed to treat human organic wastes. As the population has grown, and technology has advanced more and more different substances find their way into the municipal sewer systems and we expect the treatment process to remove them. The conventional levels of treatment are referred to as primary, secondary, and tertiary, or advanced secondary treatment. Each higher level of treatment removes additional types of substance. For example, primary treatment is a physical form that removes large objects by settling. Secondary treatment includes a biological component that works to settle out solids and decomposes organic material. The tertiary or advanced secondary treatment adds another permutation or combination of processes that removes more solids and some soluble substances. However, there are many substances that none of these processes will remove that then may become environmental and human health concerns.

Are treatment facilities required to monitor and report on what comes into their facility and what leaves?
Each facility requires a permit, licence or certificate of approval to operate and discharge. Each jurisdiction has somewhat different requirements and these should be referred to by going to the legislative database for the jurisdiction of interest. Reporting of what leaves their plant is important to meet the permit requirements. Influent is not generally a requirement, other than if the operator knows the quantity and quality of the influent then he/she can better adjust their system accordingly. The municipality monitors the discharges and reports to the province. The federal government requires that there not be any substance discharged that could be deleterious to fish or fish habitat. This may contradict the provincial requirement in that they may allow certain limits of substances be discharged that could be deleterious.

What is a sewer-use by-law?
A sewer-use by-law is a tool developed by a province and/or municipality to control inputs to the sanitary sewer system. Industrial discharges to the sewer are identified and certain substances are limited by quantity and quality and time of discharge so not to disrupt the normal flow patterns or upset the treatment process. Substances to be monitored will be dependent on the type of industrial input (i.e. high technology versus chemical manufacturing, etc.). The industry may pay a sewer surcharge to the municipality to have their waste accepted. This is an excellent tool to assist in reducing contaminants to the environment either directly to water or through use of Biosolids.

How is each level of government involved in municipal wastewater management?
The federal government provides some funding for infrastructure through various infrastructure programs. Provinces and municipalities usually match these funds. The municipality builds, operates and maintain the infrastructure (collection and treatment). The province is responsible for ensuring environment impact assessments are undertaken and followed. They also then set out requirements in a permit, licence or certificate of approval for the quality and quantity of the discharge and overall facility operation. The municipality is responsible for meeting the requirements and the province is responsible for monitoring and ensuring they are met. The federal government is responsible for making sure the federal Fisheries Act is implemented with respect to fisheries habitat and non-deleterious discharges, and to enforce the Canadian Environmental Protection Act. The federal government is responsible for ensuring there are no transboundary pollution problems (e.g. Great Lakes Water Quality Agreement).

What happens to the solids components of the wastewater?
Through each step of the treatment process, depending on the level of treatment, solids are removed from tanks and may be taken to landfill or reintroduced into another phase of the treatment process for additional treatment. The final treated solids (sewage sludge) can be called "Biosolids" if they have been treated sufficiently to remove contaminants and meet requirements for use on agricultural land.