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Assessing the Efficacy of Subsurface Flow Constructed Wetland Cells for the Treatment of Land-based Fish Farm Discharge



Source water protection has emerged as a priority science area in Ontario. Aquatic systems are experiencing increased loading of nutrients, pathogens, and emerging contaminants such as pharmaceuticals. Land-based fish farms are faced with increasingly stringent regulations on the discharge of effluent. Conventional wastewater treatment systems currently used to treat aquaculture effluent are ecologically and economically expensive to build, operate, and maintain and are traditionally designed for a narrow range of parameter treatment. Constructed wetlands, also called treatment or engineered wetlands, have been shown to be effective at removing or reducing the concentrations of nitrogen and phosphorous, pathogens and emerging contaminants such as pharmaceuticals and personal care products in wastewater effluent. Constructed wetlands have also been shown to be effective in specialized applications, including removing nutrients, metals, and pesticides from golf courses, treating mine and aggregate extraction waste, and mitigating the impacts of concentrated animal farming operations, or CAFOs. Much of the research on treatment wetlands has been done in warmer or more moderate climates (equatorial areas, US, Europe). It is felt that properly designed wetlands can perform satisfactorily in colder climates. More research is needed to validate applications of constructed wetlands that would be subject to regulation by the Ontario Ministry of the Environment, the Ontario Ministry of Agriculture, Food, and Rural Affairs, and/or the Ministry of Municipal Affairs and Housing through the Ontario Building Code.

Program Name

Aquaculture Collaborative Research and Development Program (ACRDP)


2007 - 2010


Central Canada: Great Lakes, St. Lawrence Freshwater Drainage Basin

Principal Investigator(s)

Tom Pratt

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