Cornwall Wastewater Treatment Plant
Located at 2800 Montreal Road, the City of Cornwall Wastewater Treatment Plant was originally built in 1968, and the facility has undergone several expansions since that time.
The treatment plant is currently undergoing a $55.5-million upgrade that will result in the addition of secondary treatment and an increase in capacity.
The existing plant currently serves approximately 46,000 residents as well as numerous commercial and industrial customers. It has an average rated capacity of 54,000 cubic metres per day and a peak design capacity of 108,000 cubic metres per day.
Sewage from the City of Cornwall is collected and transferred by gravity to a pumping station on the south side of Montreal Road, near the entrance to the Wastewater Treatment Plant.
The sewage passes through a screen at the pumping station before being pumped through a forcemain to the treatment plant, where grit is removed in aerated grit tanks. After degritting, the sewage is transferred to four clarifiers where it is disinfected using chlorine. The treated effluent is then discharged into the St. Lawrence River.
Solids that settle in the clarifiers are pumped to two digesters where organic matter is decomposed and methane is generated. This methane is used as a fuel for building heat. The decomposed organic matter is removed from the digesters, dewatered in centrifuges and landfilled for final disposal.