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Waste Water

We invite you to consult one of the following topics:

Water treatment systems for isolated dwellings
Application of the regulation
Main components and operation
Drainage of the septic tank
Contaminants from septic systems
Steps for installing a septic system

The sewer network
Wastewater treatment by aerated lagoons
Wastewater  treatment through the roseau épurateur

Water Treatment Systems for Isolated Dwellings

Owners of isolated dwellings must ensure that their wastewater is treated by means of a wastewater treatment and disposal system (septic system), for which the standards of installation and treatment can be found in the provincial regulation Règlement provincial sur l’évacuation et le traitement des eaux usées des résidences isolées (R.R.Q., c. Q-2, r.22).

This regulation contains all of the standards to be followed when designing and modifying septic systems.  Municipalities have the responsibility of enforcing this regulation.

Application of the regulation

When should the standards be applied?

  • When constructing a new residence, a septic system must be installed in accordance with regulation Q-2, r.22.
  • When there is a change in the number of bedrooms, it may be necessary to increase the capacity of the system, in accordance with the regulation.
  • When carrying out work on the wastewater treatment system, it must comply with the standards of the regulation.
  • When there is a nuisance or contamination of the environment by wastewater, the situation must be corrected or the system replaced, if it was installed prior to 1981.

Main components and operation

According to the regulation standards, wastewater treatment and disposal systems must, in most cases, be equipped with a septic tank and a functioning filter bed. Figure 1 illustrates these components:

Installation sanitaire

Figure 1:

The main components of a wastewater treatment and disposal system (as amended from the Technical Guide on wastewater treatment for isolated dwellings)

The septic tank is a watertight container that receives the wastewater from the dwelling. It allows the suspended particles to settle to the bottom and retains the floating particles that could block the pipes of the filter bed.

The suspended particles that settle at the bottom are sludge. This sludge contains bacteria that digest this matter to convert it into water. The water then seeps into the filter bed (i.e. seepage bed, above-ground sand filter, etc.), where the treatment will be completed before release into the environment. Among other things, the filter bed destroys disease causing microorganisms

For efficient wastewater treatment, the filter bed must be located on permeable and well aerated soil

Drainage of the septic tank

To maintain the efficiency of the system, the septic tank must be drained regularly. Draining prevents solids and scum from seeping into the filter bed and blocking the pipes.

Every owner of a septic or holding tank is obliged to have it emptied. The frequency depends on whether the residence is occupied permanently or seasonally:

  • A septic tank that is used year-round (a residence that is occupied on a constant or periodical basis) must be emptied at least once every two years
  • A septic tank that is used seasonally (a residence that is unoccupied for more than 180 consecutive days) must be emptied at least once every four years.

In order to ensure that all septic tanks are emptied regularly, the Municipality adopted regulation nº1011, requiring citizens to provide the Municipality with a copy of their receipt for tank emptying. You can find the regulation HERE. Formulaire à compléter

In order to ensure that all septic tanks are emptied regularly, the Municipality adopted regulation nº1011, requiring citizens to provide the Municipality with a copy of their receipt for tank emptying. You can find the regulation HERE

When having your tank emptied, don’t forget to ask for your receipt and bring/send it to the Municipality of Rawdon’s Department of Permits and Inspections.

Contaminants from septic systems

In Québec, the most commonly used wastewater treatment system for isolated dwellings is treatment by soil infiltration (i.e. seepage bed, above-ground sand filter, etc.). This technique has proven itself to be successful and favorable, where applicable. However, when a system is installed on inappropriate soil, or is used or maintained incorrectly, certain contamination problems can occur.

Septic system contaminants are numerous: nutrients, bacteria, viruses, chemicals.

Nutrients

Most septic systems are not designed to treat phosphorus in residential wastewater, even if the systems meet the Q-2, r.22 regulation standards.

A portion of the phosphorus discharged from the septic system will affix itself to the soil particles around the filter bed. Depending on local soil properties, groundwater levels and distance, a certain amount of phosphorus can make its way to surface water, which will cause accelerated eutrophication of watercourses.

To ensure increased phosphorus purification, it is important to keep your shoreline covered in vegetation (including grasses, shrubs and trees) between the septic system and the lake. The plants will capture some of the phosphorus before it reaches the lake or watercourse. You should also make sure to use phosphate-free household products.

Bacteria and viruses

Inadequately treated wastewater or wastewater that is released directly into the environment can contain bacteria such as E. coli or viruses such as hepatitis A, which can cause serious health issues if they make their way into a drinking water source. Consequently, it is very important to correct any malfunction resulting in the direct discharge of wastewater into the environment.  

Chemical products

Finally, household chemical products (i.e.: solvents, pesticides, used oils, etc.) must be disposed of in a Hazardous Household Waste (HHW) depot instead of being flushed into the septic system, so as not to contaminate ground water and nearby soil.

Steps for installing a septic system

There are several advantages to owning a septic system that meets Q-2, r.22 regulation standards:

  • Increases the value of your property;
  • Ensures a compliant and sustainable system, as the technologies are approved by the Bureau de normalisation du Québec;
  • Improves protection of ground water, the water quality of surrounding wells and ultimately of human health ;
  • Improves protection of watercourses (streams, lakes).

Here are the steps to follow for the installation of a compliant septic system:

1) Contact the inspector of the Municipality of Rawdon’s Department of Permits and Inspections, to understand the steps to be taken and to get answers to your questions.

2) Appoint a member of a competent professional order who will: :

  • Determine the minimum hydraulic capacity of the system (depending on the number of bedrooms in the case of a residence).
  • Undertake a characterization study of the site and natural terrain.
  • Devise a location plan, to scale.
  • Ascertain which treatment system is best suited to your lot and meets with Q-2, r.22 regulation standards.

3) With the documents provided by your technologist, you will be able to approach contractors for submissions. The documents will also have to be given to the municipal inspector for approval.

4) Obtain a municipal permit.

5) Proceed with the installation of the system.

For more information of wastewater treatment of an isolated dwelling, please consult the Frequently Asked Questions of the MDDEFP:
http://www.mddelcc.gouv.qc.ca/eau/eaux-usees/foire-questions/faq.htm#a7

You can also refer to the technical guide on the treatment of wastewater of isolated dwellings:
http://www.mddelcc.gouv.qc.ca/eau/eaux-usees/residences_isolees/guide_interpretation/index.htm#annexes

The sewer network

A part of the Village sector of Rawdon is served by a sewage system that collects residential, industrial, commercial and institutional wastewater as well as storm water. A section of the sewer network is made up of a combined system, in which both wastewater and storm water circulates in the same underground pipe. This wastewater is a mixed with street and parking lot runoff, as well as runoff from flat roofs, foundation drains and the sump pumps (basement waterproofing system) of certain residences.

These waters run under kilometres of streets and can be pumped several times before reaching the municipal wastewater treatment station.

The disadvantage of a combined system is that wastewater is diluted by the storm water. This makes treatment of the water at the station more difficult because the volume of water to be treated is higher and the system is not optimized to treat diluted water.

In order to facilitate the treatment of wastewater at the station, if possible, it is recommended to do the following:

  • Citizens residing in front of ditches should direct the water from their French drain and/or sump pump into the ditch and not into the sewer (national building code);
  • Runoff from roofs should be directed onto a filtering plant bed that can absorb rain water or into a rain barrel (used for watering plants), instead of into the sewer;
  • When designing new parking lots, runoff water should be directed into a filtering plant bed;
  • Businesses and industries must make sure that any discharges into the sewer network meet with the standards of Regulation 332-87, available HERE

Wastewater treatment by aerated lagoons

The wastewater that is sent to the treatment plant first undergoes a pre-treatment, which consists of mechanically removing the insoluble waste. The water is passed through a grid which removes the largest waste, this is called screening. It then circulates into an apparatus that removes the sand and gravel.

Following the pre-treatment, the water is sent into 4 aerated basins, where it is possible to reproduce the phenomena of natural self-purification. Bacteria present in the wastewater are used to breakdown pollutants. The water is kept in these basins for 10 days and is then discharged into the river.

Although this type of water treatment, which is used in Québec, eliminates most of the pollutants found in wastewater (i.e.: suspended particles, sand, waste, phosphorus), the use of aerated basins does not allow for the total removal of all toxins and substances found in wastewater.

It is, therefore, very important not to dispose of hazardous household products (i.e.: oils, paint, solvents, pesticides, medication) down the sink, the toilet, manholes out on the street, since water treatment cannot eliminate them completely. These products must be brought to your local Hazardous Household Waste depot:

2101, Adélaïde St.
Every Friday, from May to September, from 10 am to 4 pm | One Friday in the month of October, from 10 am to 4 pm

Wastewater treatment through the roseau épurateur

On Desneiges Avenue, wastewater is not directed into aerated basins but rather into a community system that uses the roseau épurateur. This system is equipped with a septic tank that collects the wastewater and then directs it into a filter bed that is covered with very specific plants. Slopes facilitate the flow of water beneath the surface and promote natural aeration of the system. This filter bed is home to numerous varieties of microorganisms that purify the wastewater.

Since the wastewater is pumped into the filter bed, it is important not to dispose of any type of tissue/fabric (wipes, rags, sanitary napkins, etc.) or any other element which could block the pump. In short, do not use your toilet as a trash can! We are counting on your cooperation to ensure the good working order of the system.