Originally commissioned in 1929, the North Toronto Wastewater Treatment Plant is one of four wastewater treatment facilities operated by the City of Toronto. Located in the Don Valley, the plant currently serves a population of about 55,000. The facility operates at a rate of about 7.5 million gallons per day (mgd) with major treatment processes that include screening and grit removal, primary treatment, secondary treatment, phosphorus removal, effluent disinfection and dechlorination. Before being discharged into the Don River, final effluent at the North Toronto plant is disinfected with sodium hypochlorite and dechlorinated with sodium bisulphate. The end result is a high-quality effluent that has consistently surpassed the requirements of the Ontario Ministry of the Environment (MOE). To ensure safety and reliability, the systems that transport the sodium hypochlorite and sodium bisulphate are double contained to prevent any possible leaks or spills.