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Wastewater collection and treatment

Wastewater is thoroughly treated at the Robert O. Pickard Environmental Centre to ensure it is safe for the public’s health and the environment.

Wastewater treatment

Wastewater is water that has been used and discharged by homes, businesses and industries. It is 99.9 percent water by weight, with a very small portion (0.1 percent) of dissolved and suspended solids.

Wastewater is thoroughly treated at the Robert O. Pickard Environmental Centre to ensure it is safe for the public’s health and the environment. For a detailed description of each treatment stage, download our wastewater treatment brochure: Let's Explore Wastewater Treatment.

Treatment process

1. Preliminary:

  • Coarse screening/pumping: Wastewater flows to the plant through enormous pipes buried deep in the ground. Once the wastewater arrives at the treatment plant, any object bigger than a shoe gets screened out.
  • Fine screening: Screens will catch smaller objects like sticks and rags.
  • Grit removal: Degrit tanks separate pebbles, grit and sand from the other solids that can be further treated.

2. Primary:

  • Removal of settled solids (sludge) and floatable material (scum).

3. Secondary:

  • Naturally occurring bacteria remove dissolved and suspended organic pollutants. Removal of phosphorus takes place by adding a solution of iron to the wastewater. Iron captures the phosphorus, creating a solid that can sink and be separated from the water. 

4. Disinfection:

  • Before it is finally returned to the Ottawa River, the treated water is first disinfected using sodium hypochlorite, year round.

Process control

Protecting the health of the Ottawa River is an important part of treating wastewater. Processing of wastewater or sewage is monitored 24/7. Sensors throughout the plant allow staff to monitor the treatment process and notify them of any problems. The monitoring and testing program ensures quality targets are met and potential process problems are identified early.

Generating electricity at the Robert O. Pickard Environmental Centre (ROPEC)

As wastewater is treated and processed, methane and carbon dioxide are produced. In 1998 a process was added to convert these gases into electricity and heat through a process called cogeneration. Cogeneration produces 5 megawatts of heat and electricity which provides 50% of ROPEC's energy needs on an annual basis. The cogeneration facility produces enough electricity for approximately 1,500 homes.


The Robert O. Pickard Environmental Center meets all provincial guidelines for wastewater effluent as defined by the Ontario Ministry of the Environment.

Actual volume of wastewater treated at the Robert O. Pickard Environmental Centre

  Capacity (millions of litres/day) Actual (2017)
Average 545 470
Peak 1,362.5 1,435

Ottawa’s wastewater treatment plant

About the Robert O. Pickard Environmental Centre (ROPEC)

  • Provides secondary level treatment (physical and biological) of domestic, commercial and industrial wastewater - returning treated water to the Ottawa River.
  • Situated on 67 hectares of land adjacent to the Canotek Business Park in Ottawa East. 28.4 hectares remains available for future growth.

An aerial view of the Robert O. Pickard Environmental Centre.


  • Originally built in 1962, providing primary level treatment, and called the Green’s Creek Pollution Control Centre.
  • Expansions in 1971 and 1975 to provide needed capacity for the growing City.
  • Major expansion and rehabilitation from 1988 to 1993 increasing treatment capacity, improving biosolids processing, and adding odour control. Level of treatment improved from primary treatment to include biological secondary treatment.
  • Renamed for Robert O. Pickard, retired Commissioner of Works in the former Regional Municipality of Ottawa-Carleton.
  • Mr. Pickard helped initiate an expansion and upgrade of the centre to provide Ottawa with improved wastewater treatment capacities.
  • Addition of dechlorination process in 2013 to remove chlorine prior to discharge of treated water to the Ottawa River.

Sewer collection system

Ottawa's sewer collection system gathers wastewater from homes, businesses and industrial sites, transporting the waste through a network of sewers, pumping stations and forcemains to trunk sewers. The wastewater then flows to the Robert O. Pickard Environmental Centre for treatment.

Ottawa’s sewer system covers 2,796 square kilometres and extends from West-Carleton to Cumberland. It includes:

  • 2,853 km of sanitary sewers
  • 102 km of combined sewers
  • 61 wastewater pumping stations
  • More than 90,000 public maintenance holes
    • 1,656 combined
    • 42,617 sanitary
    • 46,451 storm
  • Approximately 234,000 service connections
  • Sewer pipes ranging in size from 20 cm to three metres in diameter

In the rural areas, a variety of collection methods are used:

  • Richmond, Munster Hamlet and Carp are connected to the municipal trunk system.
  • Elsewhere individual septic systems are used and the sludge from septic tanks is transported to the Robert O. Pickard Centre for treatment.

Stormwater collection system

Storm sewers carry rainfall and other surface runoff directly to the nearest creek, stream or river, frequently with limited or no treatment. Everyone plays a role in preventing pollutants from entering the storm sewer system and damaging the water ecosystem. Over time, stormwater collection has graduated from being concerned only with draining excess water away as quickly as possible, to flood and erosion prevention in waterways to restoring water quality before releasing to nearby waterways.

Various practices are used to manage stormwater runoff throughout its journey from rain to river. Stormwater management begins with lot-level controls where rain first drops. It then proceeds to conveyance controls which help transport stormwater. Finally, end-of-pipe measures treat stormwater before it is discharged into our local waterways.

The City of Ottawa maintains a network of culverts, storm sewers and municipal drains that transport stormwater to nearby creeks, lakes or rivers. In Ottawa, the stormwater system includes:

  • More than 2,700 km of storm sewers
  • More than 300 stormwater management facilities including 158 stormwater ponds, 12 stormwater pumping stations, underground storage, bioswales, and oil and grit separators
  • 1,200 km of municipal drains in rural areas

Lot-level controls

Lot-level controls are measures implemented at individual private and public lots that help reduce the volume of runoff coming from properties and the amount of pollutants carried by runoff. Effective and sustainable stormwater management starts at the source where rain falls. To help protect our water supply, visit how to reduce your stormwater impact.  

Typical lot level measures include:

  • Downspout redirection: Downspout redirection diverts flows from roof tops to areas such as grass, gravel, or infiltration trenches. This reduces the quantity of stormwater that must be treated by reducing the amount of stormwater flowing onto impervious surfaces such as driveways which drain directly to the storm sewer system.
  • Rain barrels and cisterns: Rain barrels and cisterns capture roof runoff and temporarily store it for reuse. This practice reduces runoff and pollutants, and can provide a benefit in terms of reduced water consumption.
  • Rain gardens and other absorbent landscaping: Rain gardens are designed to absorb and clean stormwater by capturing runoff in human-made depressions lined with water thirsty (hydrophilic) plants and soil that encourages infiltration. This lot-level measure decreases peak flows through additional on-site storage and reduces pollutants released into the stormwater system through plant/ground absorption.

Conveyance controls

Conveyance controls are used to treat, limit and/or control storm water before reaching the municipal storm sewer. Typical conveyance control measures include:

  • Catch Basins: Openings along curbs and parking lots where rainwater enters the storm sewer system designed to capture heavy debris and grit. Storm sewer catch basins are usually marked with a fish to remind people that stormwater eventually makes its way into nearby waterways.
  • Bioswales: Vegetated, shallow, open channels designed for conveyance and treatment of stormwater runoff, particularly from roadway drainage. Grass swales can sometimes reduce runoff volumes and pollutant loads by filtration through the vegetation. Plants are often selected due to their ability to filter sediments and nutrients.
  • Infiltration Trenches: Long, narrow, rock-filled trenches that receive stormwater runoff from roadways or landscaped areas. These trenches are effective in removing fine particles and associated pollutants.
  • Perforated Pipe Systems: Perforated pipes have tiny holes that allow water to filter into the surrounding soil. This measure reduces the quantity of stormwater runoff that is managed by the stormwater collection system.
  • Oil-Grit Separators (OGS): An oil-grit separator (OGS) uses separate chambers to remove coarse sediments (grit), oils and other buoyant pollutants (floatables).
  • Inlet Control Devices (ICDs):  Much like an hour glass, ICDs are engineered to only allow a certain amount of stormwater over time. ICDs are located throughout various storm water entry points and help manage stormwater quantity when storm sewer capacity is exceeded. ICDs prevent stormwater from discharging at critical points in the stormwater collection system and redirect it to parking lots, parks, or underground storage.
  • Street Cleaning: Streets are a significant contributor of pollutants to urban runoff. Street cleaning can reduce this impact. The City of Ottawa uses tandem street cleaning machines that use brooms and vacuums to prevent debris from entering our stormwater system.
  • Smart About Salt Program: During the winter, the City manages the use of rock salt on roads and parking lots. While this is a necessary tool to help combat Ottawa’s fluctuating winter climate, it is important to ensure we understand the impact of using too much salt. That is why the City has partnered with the Smart About Salt Council to become an active participant in the Smart About Salt Program.

End-of-pipe measures

End-of-pipe measures treat and/or control stormwater before it flows back into natural waterways. End of pipe measures used in Ottawa include:

  • Biofilter: A biofilter uses grass or other dense plants to filter out sediment and nutrient material before re-entering local waterways. As stormwater passes through the plants, pollutants are removed. Biofilters provide treatment for pollution but do not control the amount of stormwater passing through them. 
    photo of biofilter
  • Underground Storage Tanks: The use of underground storage tanks help control the flow of stormwater and aid in preventing flooding, erosion and combined sewer overflows. Stored water is released back into the storm sewer system at a reduced rate, decreasing the stresses placed on downstream stormwater infrastructure.  
  • Stormwater Ponds: Stormwater ponds receive stormwater runoff and hold the water back for a period to allow pollutants to settle before they are discharged into a watercourse. The controlled release rate also helps prevent flooding and erosion.

Get to know your local stormwater pond Ottawaphoto of a stormwater pond

There are three main types of stormwater ponds in Ottawa:

  1. Dry Ponds: Designed to be dry most of the time and temporarily detain water to prevent overloading the storm sewer system during large storms. The stored water is released back into the storm sewer system at a reduced rate, preventing downstream flooding. These facilities are often incorporated as depressions in parks or adjacent to roadways.
  2. Infiltration Ponds: Collected stormwater filters into the ground, improving water quality as it slowly passes through the soil. These ponds are also capable of recharging or replenishing the groundwater table. Suitable sandy soils are required for these special facilities and are not common in the Ottawa area.
  3. Wet Ponds: Water levels in wet ponds rise and fall with each storm, but they always hold a certain volume of the water and may include man-made wetland features. Wet ponds are intended to mimic natural lakes and often have healthy aquatic ecosystems including fish, bird and waterfowl populations. Never consume any fish caught from a stormwater pond.

Always remember:

  • Stay out of stormwater ponds. Recreational activities such as swimming, wading, and fishing are prohibited for your own health and safety. These ponds contain surface pollutants such as oil, metals, and feces
  • Stay off the ice in the winter as water levels and flows change rapidly making skating or other activities extremely dangerous
  • Protect your pet’s health and safety by keeping them out of stormwater ponds 

Reducing your impact on stormwater

We all play a part in reducing the impact of stormwater in our community. Help keep stormwater clean by following these tips:

  • Vacuum, sweep, and use rags or dry absorbents on your driveway - don’t hose it down
  • Select native and adapted plants that require less fertilizer to minimize runoff
  • Apply lawn and garden chemicals sparingly and according to directions. Ontario's province-wide pesticide regulation prohibits the sale and use of most pesticides for cosmetic purposes on lawns, gardens, park and schoolyards.
  • Deposit yard waste in your green bin to prevent catch basin blockages
  • Wash vehicles at a car wash so that cleaning products do not flow directly into the storm sewers or ditches
  • Check underneath your car to ensure engine fluids are not leaking
  • Dispose of chlorinated and salt water pool wastewater using the City’s pool maintenance tips.
  • Keep litter, pet waste and debris out of street gutters, storm catch basins and ditches so they are not washed directly into streams, rivers, lakes and wetlands
  • Always pick up after your pets. Stormwater will carry feces into local waterways increasing the total E. Coli and bacteria levels
  • Dispose of used oil, antifreeze, paints and other household chemicals at a household hazardous waste depot or Take it Back! retailer, not into catch basins or ditches
  • If you’re unsure of how to dispose of any chemicals or household hazardous materials, consult the City’s Waste Explorer
  • Take part in cleanup initiatives such as the great Canadian Shoreline Cleanup or Ottawa’s very own bi-annual GLAD Cleaning the Capital!
  • If you spot someone pouring harmful material into a catch basin, call 3-1-1
  • Ensure cigarette butts are disposed of safely in a designated spot. More than 85,000 cigarette butts were gathered as part of Ontario’s Great Canadian Shoreline Cleanup in 2014.
  • Don’t feed geese and other wildlife. One bird’s dropping can contaminate up to one acre of water

Soak it up and slow it down:

  • Maximize infiltration of rain into the soil to recharge groundwater and protect aquifers for the future.
  • Reduce peak stormwater flows through rainwater-harvesting and natural landscaping. Feed your garden not the storm drain!
  • Redirect your downspout to drain away from hard surfaces such as asphalt or patio stones onto grass, gardens, or an infiltration trench
  • Install a rain barrel to use rainwater at a later date
  • Plant trees, shrubs and ground cover to reduce soil erosion
  • Keep stormwater on your property through smart stormwater landscaping such as building a rain garden or infiltration pit
  • Reduce the amount of impermeable surfaces on your property such as patio stone or asphalt and replace with permeable options such as interlock, gravel, or grass

For other ways on how you can do your part, please see the resources below:

Stormwater: Frequently asked questions

What is stormwater runoff?

Stormwater runoff is rain or melting snow that collects on the surface or flows into sewer pipes instead of seeping into the ground.

Runoff will either:

  • Soak into the ground
  • Get absorbed by plants
  • Evaporate
  • Flow along the surface to the nearest sewer or waterway

In urban areas, we have a greater amount of runoff since we have decreased our natural ability to soak up water. When fields and forests are replaced with roads, parking lots and buildings, less rainfall can soak back into the ground and more water collects on hard surfaces. This increased runoff quickly drains via paved surfaces and storm sewers to local streams and rivers. For a brief video explanation, visit the Eastern Subwatersheds Stormwater Management Retrofit Study.

Why should I care about stormwater?

When we replace plants with pavement, we decrease the city’s natural ability to soak up stormwater.  This means that when it rains, less water soaks into the ground and more water collects on the surface.  A small storm can cause a surge in the levels and flows of rivers and streams which can lead to flooding and erosion.   

In addition to increased volume and speed, the runoff picks up pollutants like dirt, oil, and animal waste as it flows over the surface and decreases the quality of our local waterways.  Eventually, all stormwater reaches the Ottawa River which is the drinking water source for Ottawa and many downstream communities. With extreme weather events becoming more frequent, managing stormwater is even more important to reduce flooding and protect water quality.

How does stormwater become polluted?

Rain or melted snow falls on roofs, driveways, parking lots and roads and travels as runoff to reach a waterway. This runoff collects various pollutants (dirt, phosphorous, metals, nitrogen, animal waste) and debris (grass-clippings, garbage, cigarette butts) as it flows over these surfaces, resulting in polluted water.

What is the difference between a storm, sanitary, and combined sewer?

In Ottawa, we have three types of sewers:

  1. Storm sewers carry rainfall and runoff directly to either a stormwater pond or the nearest creek, stream or river, generally without treatment.
  2. Sanitary sewers gather wastewater from homes, businesses and industrial sites, and transport the waste through a network of sewers to the Robert O. Pickard Environmental Centre for treatment.
  3. Combined sewers carry both wastewater and runoff to the Robert O. Pickard Environmental Centre for treatment. These sewers are located in the downtown core and can overflow into local waterways if stormwater exceeds their capacity.

What does the fish symbol on a sewer grate mean?

Storm sewers are often marked with a fish symbol to remind that it drains to local rivers and streams. The fish symbol is there to remind the public that what goes down the drain can harm our rivers and streams. Remember: Only rain goes down the drain.

How does the City manage and treat stormwater?

Stormwater management has been applied to new urban developments in Ottawa since the 1980s. Over the last few decades it has evolved to include improving water quality and reducing the total amount of runoff by designing sites to allow more rainfall to soak back into the ground. Stormwater facilities such as man-made ponds, culverts and catch basins are built to temporarily hold water.

Ponds also provide water quality treatment via filtration to remove pollutants or and debris. The “cleaned” water is then slowly released back to the natural waterway, mimicking the natural runoff rate and quality. This helps prevent flooding and stream bank erosion.

In older areas of the city, stormwater runoff drains directly to creeks and rivers with no treatment or control of any kind. The continued discharge of uncontrolled stormwater runoff to the Ottawa River and its tributaries has been recognized as an important issue for the City to address. The City launched the Ottawa River Action Plan (ORAP) in 2010 to improve and protect the health of the Ottawa River and its tributaries.

What happens to stormwater in rural areas?

In rural areas, stormwater runoff infiltrates through a greater amount of impermeable surfaces. However, runoff can be subject to agricultural by-products such as excess fertilizer, pesticides and manure. The runoff from agricultural operations can have an impact on surface water sources such as groundwater, streams, lakes, and rivers. The Ottawa Rural Clean Water Program provides funding to improve surface water and groundwater quality. 

Sewer cleaning

The City of Ottawa conducts routine cleaning of sewers to ensure that wastewater from homes and businesses is efficiently transported to the Robert O. Pickard Environmental Centre (ROPEC), the City’s treatment facility.

Learn More

Sewer odours

Who do I call if there is a strong sewer smell coming from outside my home?

Call 3-1-1.

What to do if there is a strong sewer smell coming from the basement?

To prevent smells from the sewer entering your home, the plumbing in your basement has a ‘trap’ installed that creates a barrier when filled with water. The trap is under the floor in the basement and is the first place to look if you have odours in your home.

  • Sometimes in older homes the water in the trap leaks or evaporates and the barrier is broken. To reintroduce the barrier, pour a few cups of water in the basement floor drain.
  • In newer homes, the trap in your home is kept full through a discharge from the trap seal primer valve. If this odour occurs in newer homes, check to see if the primer valve is operating properly or call a plumber.

If the smell persists after a few hours or if the smell is from a sewer back-up, please contact 3-1-1.

What to do if there is an offensive odour coming from one of my sinks?

Often residents may experience an offensive odour while near a sink or after filling a glass.  If you think the odour is from the glass of water, take the glass to another room.  If you no longer detect the odour from the glass, it may be the sink that is the source of the odour.  Often a little commercial drain cleaner will remove any material collected in the trap of the sink that is creating the odour.

Combined sewer overflows (CSOs)

What is a combined sewer overflow (CSO)?

The City of Ottawa has three types of sewers: wastewater, stormwater, and combined. 

  • Wastewater sewers: Collect wastewater from homes, businesses and industries, and transport the wastewater through a network of sewers, pumping stations and forcemains to main or trunk sewers, and direct it to the Robert O. Pickard Environmental Centre for treatment. 
  • Stormwater sewers: Carry rainfall and other surface water run-off directly to the nearest creek, stream or river, generally without treatment.
  • Combined sewers: Collect and transport both sanitary wastewater and stormwater runoff in a single pipe. This type of collection system was typically installed from 1880 to 1960 and is still in operation in older areas of most Canadian cities.

During dry weather, wastewater is collected and carried from a combined sewer to the City's wastewater treatment plant. During heavy rainstorms or snowmelts, the combined sewer may not be able to handle the high volume of stormwater runoff entering the system. Most of the wastewater is transported to treatment plants via the wastewater pipe, but to prevent flooding and sewer backups, some of the rain and wastewater mixture is diverted as overflow into the river.

The practice of discharging overflows during the normal operation of combined sewer systems is accepted by the Ministry of the Environment and Climate Change. In Ottawa, these events are monitored and reported to the Ministry of Environment and Climate Change and downstream users such as water purification plants and special interest groups.

Overflow activity: Information and estimated volumes for the current year’s overflow activity.

What is the City doing to prevent overflows?

The City of Ottawa has implemented the following plan to mitigate the impact of combined sewer overflows into the Ottawa River:

  • Real time controls (a system that permits the remote activation and control of overflow equipment combined with continuous monitoring of pipe flow data to maximize the capture and treatment of wastewater flow from combined sewer systems) to ensure maximum capture of overflows before they occur
  • Building storage facilities to hold the additional volume of wastewater (from combined sewer systems) generated during wet weather events
  • Continuing sewer separation projects over the next several years
  • Review the effectiveness of the current sewer separation program in comparison to other projects
  • Develop and implement a Wet Weather Infrastructure Management Plan
  • Installed devices to remove floatable material from wastewater and prevent it from reaching the river in the event an overflow occurs

The City has been working for many years to separate remaining combined sewers. The value of the work completed to date is estimated at $750 million. With the current funding framework, it is expected the planned separation work will be completed in approximately 25 years.

The City has made the following improvement to existing systems:

  • Water level, flow monitoring and alarm devices have been installed in major combined sewer overflows and are monitored daily to alert staff if an overflow occurs
  • Strengthened protocols to provide prompt notification to the MOECC Spills Action Centre and Council in the event of an overflow
  • Construction upgrades are in process for the overflow sites that were the major contributors to the total volume of sewage released during combined sewer overflows
  • Improved regulator inspection and maintenance are improved and now scheduled monthly, weekly after each rain and within 24 hours of receiving an alarm

Sewer overflow sites

There are 13 locations in Ottawa where sewer overflows may enter the river:

Map of Ottawa combined sewer overflow outfall locations

  1. Ladouceur CSO Outfall
  2. Merton CSO Outfall
  3. Booth Regulator Overflow and Brickhill CSO Outfall
  4. Kent Regulator Overflow
  5. Rideau Regulator Overflow
  6. Keefer Regulator Overflow
  7. Dufferin CSO Outfall
  8. Hemlock CSO Outfall
  9. Sandridge Storage Tank Overflow
  10. Alvin Heights CSO Outfall and RCAF CSO Outfall
  11. RCAF West CSO Outfall
  12. Springhurst CSO Outfall
  13. Clegg Street CSO Outfall

Combined sewer overflows are generally diverted to flow into the Ottawa River.

The three combined sewer overflow sites that contribute the largest volumes of CSOs are:

  • Rideau Regulator Overflow
  • Booth Regulator Overflow
  • Keefer Regulator Overflow

Overflow activity log 

The log of overflow activity is an electronic reporting system that informs the public when an overflow occurs.  Overflow information is updated when there is a combined sewer overflow. 

  • Overflow activity: Information and estimated volumes for the current year’s overflow activity.
  • Historical overflow activity: A summary of the sewage overflow volumes and total precipitation that occurred each year from 2006 to 2017.

Overflow activity (January 1, 2018 to date)

PLEASE NOTE: The volume indicated in the chart below (CSO) denotes the volume of combined overflow mixture which is comprised of storm water and wastewater. The majority of overflows occur during heavy rain and snowfall/melting periods. The chart below indicates the date, cause, and volume of each overflow event.

  • CSO: Combined Sewer Overflow
  • SSO: Sanitary Sewer Overflow
Date Event Cause Volume (m3)
01-11-2018 CSO Rain 36,450 m3
02-28-2018 SSO Maintenance Activities 0.08 m3
03-21-2018 SSO Forcemain Commissioning 10 m3
04-28-2018 CSO Rain 210 m3
05-20-2018 CSO Rain 7,530 m3
06-03/04-2018 CSO Rain 68,530 m3
06-14-2018 CSO Rain 3,860 m3
06-18-2018 CSO Rain 52 m3
07-17-2018 CSO Rain 2,180 m3
07-23-2018 CSO Rain 22,420 m3
07-25-2018 CSO Rain 326,730 m3
07-25-2018 SSO Rain 274 m3
07-27-2018 CSO Rain 2,370 m3
08-01-2018 CSO Rain 40 m3
08-06-2018 CSO Rain 21,530 m3
08-21-2018 CSO Rain 32,070 m3
09-05-2018 CSO Rain 410 m3

Historical overflow activity (CSOs only)

CSO activity during the Annual Reporting Period (April 15 to November 15) 

Year Number of Events Volume Precipitation (mm)
2017 79 1,611,000 m3 923 mm
2016 85 413,000 m3 495 mm
2015 80 180,000 m3 332 mm
2014 101 552,000 m3 640 mm
2013 179 213,000 m3 581 mm
2012 142 237,000 m3 523 mm
2011 161 230,000 m3 533 mm
2010 322 673,000 m3 646 mm
2009 384 851,000 m3 649 mm
2008 325 877,000 m3 600 mm
2007 253 730,000 m3 555 mm
2006 271 1,090,000 m3 796 mm


Biosolids Beneficial Use Program

The City of Ottawa is dedicated to being amongst Canada’s leaders in municipal biosolids management. Ottawa continually monitors research and new technology, follows the most stringent and proactive Best Management Practices and works to share information and build understanding.

The City of Ottawa Biosolids Beneficial Use Program is guided by the principles of the International Organisation for Standardization (ISO) No‘s 9001, 14001, and 18001, and is governed by Ontario Ministry of Agriculture and Food (OMAF), the Environmental Protection Act and the Nutrient Management Act. It is also governed by the City's own policies and protocols.

The primary outlet of the Biosolids Beneficial Use Program is agricultural land application given the large agricultural land base surrounding Ottawa. This program is a major benefit to farmers as biosolids are provided free to farmers and the benefits last for several years.

What are the benefits of the program?

The City of Ottawa strives to beneficially reuse 100% of its biosolids. The benefits include:

Environmental benefits:

  • Provides a nutrient rich soil conditioner that improves soil quality
  • Facilitates plant growth
  • Adds phosphorous to Ottawa area soils that are commonly phosphorous deficient
  • Supports the three Rs program: reduce, reuse, recycle!
  • Uses a renewable resource

Economic benefits:

  • Increases crop yields and revenues for farmers
  • Reduces the need for farmers to purchase expensive fertilizers every year as biosolid application can benefit soil conditions for up to 5 years
  • Extends the life of our landfills – saving space and money

Social benefits:

  • Supports local farming operations
  • Supports the agricultural community as an integral part of Ottawa’s identity

How does the program protect my health and the environment?

The City of Ottawa’s Biosolids Beneficial Use Program Best Management Practices (BMPs) were developed based on the review of the literature, information gathered from interviews, and experience in the field.

The BMPs are a series of procedures designed to manage the Program in a manner that is consistent, transparent, and verifiable, and in excess of the Ontario Nutrient Management Act (2002) and Ontario Regulation 267/03.

The Beneficial Use Program is supported by the City of Ottawa's Sewer Use Program, which restricts what materials are permitted into the wastewater treatment plant and ensures that only treatable, non-hazardous substances enter the system and subsequently the biosolids.

Below is an abstract of the City’s best practices. The City’s BMPs are never less stringent than regulatory requirements. You can also view the complete City of Ottawa Biosolids Beneficial Use Program BMPs.

Abstract of City's biosolids best management practices (BMPs)
Program item Regulation (O. Reg 267/03) City of Ottawa’s Best Management Practice
Separation Distance Residential areas, commercial, community or institutional uses: No application is permitted within 200m. Sites under consideration are a minimum of 450m from any residential areas, commercial, community or institutional uses.
Land use restrictions

Pre-grazing waiting periods:

  • Horses, beef or dairy cattle; 2 months
  • Swine, sheep or goats; 6 months
Land will not be used as pastureland for a minimum period of 5 years following land application.
Resident notification Not required. The Ministry of Environment and Climate Change, the Ward Councillor, and residents within 450m of the spreading site are notified no less than 2 weeks prior to spreading.
Well testing Not required. The City of Ottawa has established a well sampling program for wells located on adjacent lots to land application sites. Wells are tested per request for indicator bacteria, nutrients and metals within 4 weeks of land application of biosolids. Wells are re-tested between 8 and 10 weeks after land application.
Site inspection Not addressed. All sites spread during one season are inspected, before, after, or during spreading, by trained City staff for conformance with the Certificate of Approval/Environmental Compliance Approval requirements and  the City’s of Ottawa's Best Management Practices.

Leadership in biosolids management

Leading by example: Award winning program

In 2012 the City of Ottawa was proud to win an award from the Water Environment Association of Ontario (WEAO) for “Excellence in Biosolids Management.” The City’s leadership in biosolids management is the result of two decades of work developing an exemplary program through implementing stringent and proactive best management practices (BMPs) and an Environmental Quality Management System (EQMS).

Staying current

City staff are active contributing members on numerous provincial and technical committees involving biosolids and stay current on issues and subjects important to overall biosolids management. A few of these include:

  • Biosolids and Residuals Committee member of the Water Environment Association of Ontario (WEAO)
  • Biosolids Committee member of the Canadian Waste Water Association (CWWA)
  • International Standards Organization (ISO) Technical Committee 275, Sludge recovery, recycling, treatment and disposal: Land Application Working Group 4

Resources on biosolids

If you have comments or questions regarding the City of Ottawa’s Biosolids Beneficial Use Program or would like to have biosolids applied to your farm land, please contact the City of Ottawa by telephone at 613-580-2424 ext. 23257, or by email at

Ontario Ministry of Agriculture and Food

For more information on provincial regulations regarding biosolids management, land application, storage, permits or plans please contact the Ontario Ministry of Agriculture and Food (OMAF) by telephone at the Nutrient Management Information Line, 1-866-242-4460, or by email at

Ontario Ministry of the Environment

For biosolids environmental incidents, spills, or legislative requirements, contact the Ontario Ministry of the Environment and Climate Change by telephone at 1-800-565-4923.

Additional resources

How were biosolids used in 2017?

100% of Ottawa’s biosolids were beneficially reused in 2017, as described in the following table.

Parameter Quantity (metric tonnes)
Total biosolids produced 47,456
Total directly applied to agricultural land 27,671
Total processed to agricultural soil products 15,167
Total processed to commercial liquid fertilizer 79
Total remaining to storage at year end for use in 2018 5,495

2017 biosolids distribution

Biosolids quality

City of Ottawa biosolids are tested every two weeks by a third-party accredited laboratory for metals, pathogens and nutrients, as well as additional testing beyond regulatory requirements. The tests consistently demonstrate that both the metal and pathogen levels of the City’s biosolids are well below regulated levels. Based on the Ontario Regulation 267/03 of the Nutrient Management Act, 2002(link is external), the City’s biosolids are Category 3 biosolids suitable for agricultural land application.

The four most recent biosolids laboratory results are published regularly. Note that all the listed parameters are well below the provincial standards.

Biosolids: Frequently asked questions

What are biosolids?

Biosolids are a product of sewage treatment that can be used as a natural fertilizer as well as a conditioner to recover contaminated or unusable soil. 

As sewage moves through Ottawa’s wastewater treatment facility, solids are extracted from liquids for further treatment. These solids are then dewatered to produce a dry, dark, nutrient-rich material called biosolid cake that closely resembles damp organic soil.

Ottawa biosolids are rich in essential nutrients for plant growth, such as phosphorous. Ottawa-area soils are naturally deficient in phosphorous and the application of biosolids helps return this essential nutrient to the soil.

Who benefits from the use of biosolids?

  • The City of Ottawa supplies, delivers and applies biosolids free of charge to eligible farms. This is a significant cost savings for farmers who would otherwise need to purchase commercial fertilizers. 
  • If you are a farmer interested in participating in the City of Ottawa's Biosolids Beneficial Use Program, please contact 613-580-2424, ext. 23257, or send an email to
  • The re-use of biosolids keeps close to 50,000 metric tonnes of biosolids out of landfills every year. This extends the life of the City landfill and is more cost-effective than other disposal methods such as incineration.

How are biosolids typically used?

As a fertilizer:
  • Ottawa biosolids are an excellent soil amendment providing a significant source of nutrients essential for plant growth such as phosphorus, nitrogen, calcium and other micro-elements. Using biosolids as a soil amendment on farm land is an effective and efficient way to increase the productivity of local soils. 
For land reclamation:
  • Biosolids can be applied to remediation sites where the material improves soil structure, provides organics and nutrients needed for plant re-growth and helps with water retention.

Do biosolids contain metals?

Yes. However, the levels are closely monitored and are well below provincial regulation limits. Also, under the Nutrient Management Act, the City is required to monitor and report to the Ontario Ministry of Agriculture, Food & Rural Affairs (OMAFRA). Some metals such as copper are considered essential trace elements for plant growth. 

The City of Ottawa operates a variety of programs to minimize contaminants entering the wastewater stream, including:

Is land application of biosolids a common practice?

Land application of biosolids is a common and acceptable practice for many North American municipalities. Ottawa has had a biosolid land application program since 1992.

What kinds of crops are fertilized with biosolids?

Ottawa’s biosolids are typically used to fertilize crops that are used for fuel or undergo further processing prior to animal consumption, such as:

  • field corn
  • cereal crops (e.g. wheat)
  • legumes (e.g. alfalfa and soybeans)

How often can biosolids be applied to farmland and how much?

The frequency of land applications varies from site to site. Several factors are considered when determining a suitable site for land application. Some of the factors include: proximity to residential areas, slope of the land, soil chemistry, drainage, crops to be grown, and nearby watercourses. Ontario Regulation 267/03 restricts the volume of biosolids that can be applied to a field to protect both surface water and ground water in Ontario.

Do biosolids have an odour?

Yes, and the City employs the following best management practices to minimize odour during land application:

  • Biosolids must be incorporated into the soil within 2 hours of their application
  • Stockpiling of biosolids in fields is not permitted
  • Local residents within 450m of the spreading location are notified a few weeks before the biosolids are applied
  • Biosolids are not spread on weekends or statutory holidays

What does the City do to assess my water quality? 

As per the City of Ottawa’s best management practices, the City offers free well water testing upon request to households adjacent to biosolid application sites. Tests will be taken up to four weeks before biosolids are applied, and between 10 and 12 weeks after application. All well test results are provided to the well owner.

Interested residents may book free well testing by calling 1-877-360-3830 or 613-260-3830. Residents may also request testing through email at

Ottawa Public Health provides free well testing to all well owners.

Why does the City apply biosolids instead of putting them in a landfill?

Land application is currently the most sustainable and cost-effective reuse option for the City of Ottawa’s biosolids. In addition, land application takes best advantage of a fixed and limited resource – phosphorus – which is essential for plant growth. Land application of biosolids redirects 50,000 metric tonnes towards beneficial reuse of material and puts valuable nutrients back into the soil.

Wastewater staff on the job

Fats, oils, and grease

Michael Mitchell, Sewer Inspector


Sewer inspector

What are your responsibilities as a sewer inspector?

The city’s wastewater collection system includes more than 5,553 kilometres of pipes, and our job is to ensure that wastewater is conveyed through these pipes securely and efficiently from your home to the Robert O. Pickard Environmental Centre (ROPEC) – the City of Ottawa’s wastewater treatment facility. This involves constant inspection and maintenance of our sewers. My role is to plan and coordinate each sewer inspection with our contractors to ensure we are onsite at the right time with the right equipment to assess and clean our pipes.

If you could let residents know one thing about your job, what would it be?

It would be that fats, oils, and grease should not be poured down the kitchen sink. Over half of the sewer back-ups in the City of Ottawa are actually caused by the build-up of fats, oils, and grease. One cup of grease from your home when combined with a cup of grease from a few of your neighbours can add-up very quickly. Grease combines with flushable wipes, paper towels, dental floss, Q-tips, and other items to form large blockages.

How does the presence of grease impact you on the job?

Grease build-up often turns a one-day job into multiple days due to extra staffing, contractor time, and the need for specialized equipment. Typically a pipe is cleaned using high-pressure water, but grease build-up forces us to use nozzle attachments of various sizes with chain-cutters that rotate at high speed to scrape grease from the pipe walls. It takes a lot longer, but it annihilates the grease! Most people do not know that grease not only clogs the pipe, but also corrodes and degrades the walls of a pipe over time.

What’s the worst grease-related incident you’ve seen?

I’ve seen a 600mm (24-inch) pipe that was completely blocked with grease – the blockage was over eight meters long! The bottom of the pipe had completely disintegrated due to the grease eating away at the pipe over time. When we inserted our CCTV robot – a remote-controlled robotic camera with mud-tires – into the pipe to have a look after we removed a blockage, it fell through the hole. We were forced to excavate to retrieve it. The CCTV camera goes through quite a lot, often emerging from a pipe covered in grease!

What are a few of the challenges working in your position as sewer inspector?

The greatest challenge of the job is the need to gain access to pipes that are often in remote or sensitive locations – such as high traffic zones, tourism destinations, or a farmer’s field. At all times we work to minimize the impact of sewer maintenance, and of course to ensure compliance with regulations set-out by the Ministry of the Environment.


Linsong Kou, Wastewater Process Engineer



Can you explain what cogeneration is?

Cogeneration is the process of converting biogas – a mixture of methane and carbon-dioxide produced in wastewater treatment – into both electricity and thermal energy at the same time – hence the term ‘cogeneration’. Biogas can be used as fuel just like natural gas. The City invested $4.5 million dollars in 1997 to install three internal combustion engines and generators to cogenerate electricity and thermal energy. The electricity generated is used to power the plant equipment and the thermal energy harvested is used in the plant process and to heat our buildings.

Could you put into perspective the scale of the process?

The cogeneration facility is able to generate 2400kw in electricity and 2700kw in useful thermal energy. The cogeneration facility has been operating continuously since October 1997 and has been able to provide 50% of ROPEC’s plant electricity and 60% of plant heating. ROPEC is one of Canada’s largest wastewater treatment plants, so that’s a lot of energy! The facility produces enough electricity to power approximately 1,500 homes. We’re currently planning to expand our cogeneration capacity by adding a fourth engine to harness and utilize even more biogas, resulting in even greater production of electricity and heat.

How does cogeneration benefit the environment and the City?

Biogas is a valuable energy resource, and it is now being put to good use. Without cogeneration there would be a complete loss of this energy when the gas is burned off. The cogeneration facility has also been saving the City approximately $600,000 annually through the reduction in the plant’s demand for utility power. Think of a cogeneration engine as you would the engine of your car. It must be maintained over time, as it logs plenty of miles – in our case running 24 hours per day, seven days per week – but as long as the engine is given some TLC, it will run a long time!

What is your biggest challenge on the job?

We try to reuse any waste produced at ROPEC, but of course wastewater is always being produced, so our equipment can’t stop for any reason. The plant has to run smoothly at all times to treat upwards of 390 million litres of wastewater per day. If a resident never realizes what we do at ROPEC then it means we’re doing our job well, but a process like co-generation is one of those success stories that you’d like everyone to appreciate.

What is the best part of your job?

I have the ability to contribute toward building a better wastewater treatment plant and protecting the environment, and I’m proud of ROPEC and our processes. When I speak with residents they come away realizing how vital we are to Ottawa’s day-to-day life, and cogeneration is a major contributor to that.

What not to flush down the toilet

Marc Gauthier, Supervisor Wastewater Maintenance and Process


Flushable wipes

What is your team’s role in wastewater collection?

The Wastewater Maintenance and Process group is responsible for maintaining the equipment that carries wastewater from a resident’s home to the Robert O. Pickard Environmental Centre – the City of Ottawa’s wastewater treatment facility. I’ve been with this group for 23 years and doing a good job means ensuring that wastewater moves along efficiently and causes as little impact as possible to the environment and to residents. We are always trying to find ways to enhance our system, find efficiencies, and prevent inconvenience to our residents.

If you could let residents know about one issue they could help prevent, what would it be?

I would like to ask residents to please not flush dental floss, hair, and flushable wipes down the toilet. These items clump together and begin to form what we refer to as rag snakes. These rag snakes block the 59 wastewater pump stations that we maintain and get tangled in the equipment. Often there are so many flushable wipes clogging our machinery that we have to clean it out every three months. Flushable wipes do not disintegrate in water. You literally have to cut these wipes off manually and in some cases scoop out grease build-up with shovels and large vacuum trucks – it’s awful stuff!

Please only flush the three Ps: pee, poo, and paper!

What is your job’s greatest challenge?

In terms of challenges, sometimes we work 12-hour shifts on a 24-hour job to repair our system. Wastewater keeps coming and you have to keep up with that volume, and that’s why eliminating flushable wipes and other items from the system is so important – it allows us to focus on the important work to be done.

What’s the strangest thing you’ve seen in the sewers?

I’ve seen backpacks, two-by-fours, and a traffic cone. Yes, a traffic cone. How it got there I don’t know. We got the alarm, investigated, and sure enough, there it was!

What’s the best part of your job?

I love the day-to-day interaction with my colleagues. We have a great group. I also like knowing we’re doing something good for the environment. Some days are challenging, but it’s nice coming to work and having a positive impact on our system and on our city. We feel good about what we do.