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Phosphorus removal technology: Thames River Phosphorus Reduction Collaborative’s water management and treatment plans

An update on the Thames River phosphorus reduction project.

June 2, 2017  By Nicola Crawhall Great Lakes and St. Lawrence Cities Initiative

A year after a plan to tackle residual phosphorus loss from farmland into the Thames River was developed, the Thames River Phosphorus Reduction Collaborative (TRPRC) is being put into action in Ontario. This is thanks to a grant from the Agricultural Adaptation Council through federal-provincial-territorial Growing Forward 2 funding programs, with matching contributions from participating organizations.

The great strength of the TRPRC is the participating partners. A collaborative steering committee has been set up, chaired by OFA vice-president Mark Reusser and Chatham-Kent mayor Randy Hope. Membership includes the OFA and its Middlesex, Essex, Kent and Lambton federations, the Great Lakes and St. Lawrence Cities Initiative, Grain Farmers of Ontario and its zone delegates, Ontario Pork, Ontario Fruit and Vegetable Growers’ Association, Ontario Agribusiness Association, Chippewas of the Thames First Nation, Upper Thames and Lower Thames Conservation Authorities, the city of London, the Chatham-Kent municipality, Land Improvement Contractors of Ontario, Drainage Superintendents Association of Ontario, Drainage Engineers Committee, Fresh Water Alliance, Bluewater Pipe Inc., and a number of federal and provincial government observers.

The TRPRC’s objective is to spread best practices and the best information available on water management and treatment options to remove phosphorus before it ends up in our waterways.  

While the TRPRC is focused on water management and drainage, it is meant to complement and be integrated with other initiatives, including the 4-R Nutrient Stewardship program, as well as erosion control and soil health measures that help keep phosphorus in the field.

The TRPRC has already made good progress in defining how phosphorus can be captured. A literature review on existing phosphorus-removal technologies was recently completed by BluMetric Environmental Inc. The study identifies three great challenges we must face. First, most phosphorus is lost during big storms and snow melt, and climate change will only make matters worse. Ontario research found that in 2011, over 90 percent of annual phosphorus runoff was lost from study fields in just three storms. The second challenge is that the most problematic type of phosphorus is soluble, which drives algal bloom growth. It is harder to retain on the land during big storms because it does not settle out of suspension and bind to soil particulates like particulate phosphorous does. Lastly, existing phosphorus removal technologies are designed for controlled flow conditions, not high velocity storms. The TRPRC is dedicated to finding solutions to these challenges through a combination of measures to retain more water on the land and phosphorus removal technologies.  


The BluMetric study identifies a number of technologies that can help, from spreading gypsum with liquid manure on fields to filtering runoff over a “sorbing” material, like calcium, aluminum or iron. Different technologies tested at various points in the drainage system (infield, in surface drainage, end of tile or ditch filter) have shown varying levels of effectiveness, from 22 to 55 percent soluble phosphorus removal. However, there is still the question of controlled flow to ensure it doesn’t bypass treatment in large storm events.  

The next critical step in the project is building a business case to provide financial and technical support to farmers and landowners who adopt water management and treatment practices. The TRPRC will reach out to farmers, landowners, drainage professionals and others later this year to hear their views on the proposed approach and learn how they keep phosphorus on the land. Companies will be invited to demonstrate the effectiveness of their technologies in capturing phosphorus on field or in the drainage system. Updates will be made at drainage, agricultural and municipal conferences throughout the year.

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