Wastewater Treatment Plant

One of the City of Cornwall's most important jobs is to collect and clean the community's wastewater before releasing it back into the environment. We do this through a network of pipes and our Wastewater Treatment Plant at 2800 Montreal Rd, which now serves around 46,000 residents and local businesses.

How we treat wastewater

The treatment process has a few key steps that protect the St. Lawrence River:

• Collection and screening: Sewage flows to the plant and passes through screens to remove large debris
• Grit removal and settling: The water is moved to tanks where sand and grit are removed, and then to clarifiers where solids settle to the bottom
• Disinfection and release: The water is treated with chlorine to disinfect it before being safely returned to the river

What happens to the solid waste

The solids that settle out are sent to large tanks called digesters. Here, bacteria break down the organic material, creating methane gas that is used to heat the plant buildings. The remaining solid material is dewatered and sent to a landfill.