Cobourg wastewater treatment plant pilot project to replace the use of chlorine with ozone treatment

The Town of Cobourg will conduct a pilot project to determine the feasibility of improving wastewater treatment by replacing chlorine disinfection with ozone treatment. The Cobourg Creek is a primary spawning ground for salmon and trout, and Cobourg is participating in the Blue Flag Program for its local beach in order to increase tourism. As such, proper disinfection of wastewater effluent is an important priority for the Town. Ozone provides disinfection with less environmental risks and limited safety concerns. The pilot will examine data over a range of operating conditions for six months, at one of the Town’s two wastewater treatment plants. Environmentally, ozone is a much stronger oxidizer than chlorine, making it a more effective disinfectant. It can be used in lower concentrations and requires less contact time to kill pathogenic organisms. Unlike chlorine, ozone completely oxidizes organic compounds and does not produce carcinogenic compounds such as trihalomethanes (THMs) that can ultimately find its way into the municipal drinking water supply. Unlike chlorine, ozone effectively catabolizes pharmaceuticals, a growing concern for municipalities. High capital and operational costs have prevented municipalities from adopting ozone systems for use in wastewater treatment plants. The Aclarus system that will be used in the town’s pilot project is more cost effective than traditional ozone systems to purchase and operate. Furthermore, it does not require the additional peripheral maintenance and safety costs that are required with systems using chlorine. Tools used in the decision making process for this pilot study will be life-cycle and maintenance cost comparisons between chlorine, ozone and other systems, such as UV. In addition, Cobourg will measure the amount of chemicals (i.e. chlorine and sulfur dioxide) that are diverted from the waterways as pre and post-ozonation effluent as well as evaluate samples upstream and downstream of the plant discharge point. The Town is committed to environmental protection, and as outlined in its Official Plan, has consulted with the Ganaraska Regional Conservation Authority regarding the proposed pilot project. Eliminating 4,800 kg of chlorine from the waterways, while concurrently reducing the Town’s annual operating costs by switching to ozone treatment, is in line with the Town's Environmental Mission Statement, "The Town of Cobourg Water Pollution Control Plant #1 will consistently and cost effectively control the chemical, physical, and biological discharges from its facility in order to minimize the impact of the treatment process on the environment." (Project description from original funding application)