The findings of a national review of contaminants in municipal wastewater were released this week by Canadian Water Network, highlighting opportunities for a more strategic, risk-based approach to investments to address uncertain risks.
The expert panel noted that keeping contaminants out of municipal systems through source control is more effective than trying to remove them from wastewater.
“Wastewater management is critical to all Canadians,” said Dr. Donald Mavinic, expert panel chair and professor of Civil Engineering at the University of British Columbia. “Over the past decade, we’ve seen an increase in contaminants in wastewater which can have adverse effects on public and environmental health.”
In the past, Canada’s wastewater systems were designed to treat human organic waste. However, as the wastes generated by our society have increased in complexity, so have the challenges of dealing with them. Pathogens, nutrients, metals, pharmaceuticals, and microplastics are some of the known and emerging contaminants of concern found in our wastewaters. The expert panel was tasked with assessing which contaminants are priorities, whether treatment options are available, and the trade-offs and opportunities involved.
Across the country, wastewater treatment is highly varied, reflecting more than a century of solutions developed in response to different geographic settings. Communities along coastlines, on the Prairies, or in remote northern locations have different needs, and the panel said that designing community-based solutions remains key.
The findings point to the need for an integrated watershed approach that considers upstream investments such as nutrient offsetting, for policies that provide greater flexibility in technology selection, and to regard wastewater treatment plants as resource recovery facilities.
The report concluded: “Canada’s approach cannot assume that all threats can be systematically identified, characterized and minimized, and must recognize wastewater treatment as part of a comprehensive management strategy addressing complex risks and multiple uncertainties.”
In October 2017, Canadian Water Network, with financial backing from Environment and Climate Change Canada, appointed an expert panel to conduct a national review of contaminants in municipal wastewater. During their six months of deliberation, the panel consulted with other experts across Canada, gathered case studies and scanned the literature in key areas of relevance.
The panel’s findings are now available in a new report, Canada’s Challenges and Opportunities to Address Contaminants in Wastewater, that was presented to municipal water leaders at Blue Cities 2018.