Per- and Polyfluoroalkyl Substances (PFAS) refer to a large class of compounds that have been manufactured since the 1940s and are present in solid waste and sewage sludge. Despite their widespread use, these compounds have become an issue of emerging concern only in the last few years. Recent studies have shown that PFAS are persistent in the environment, can be highly mobile in groundwater, have a high bioaccumulation potential, and are likely associated with health issues at very low levels. Potential risks associated with PFAS have led to increasingly stringent environmental standards in many jurisdictions in the USA and have come to the attention of regulators in Canada, including those for waste facilities. Diversion and proper disposal of PFAS impacted waste is starting to be regulated in some jurisdictions outside Canada.
As a result of the disposal of consumer and industrial products containing PFAS in landfills or use of PFAS-impacted materials for interim or final covers, these compounds are often found in leachate, groundwater and surface water at waste disposal sites. Environment Canada is monitoring select closed landfills in Ontario to assess for presence of PFAS and determination if it is a priority contaminant. The Ministry of the Environment, Conservation and Parks (MECP) has started to request monitoring of PFAS at select landfills for specific locations in Ontario. These monitoring requirements are in their infancy in Ontario and how the data is being used to assess site compliance or develop site conceptual models will be discussed.
The versatile properties that make PFAS desirable for many commercial and consumer products also present challenges for their management or eventual treatment that may be required to address current and future liability. Non-treatment management options include containment, analysis of downstream loading and receptors, and source evaluation/reduction. Should leachate treatment be required, many conventional treatment technologies are ineffective as many PFAS are not readily biodegradable, generally have low volatility and are resistant to oxidation and conventional thermal destruction. As a result, the effectiveness of commonly used treatment technologies is often reduced. Further waste sites that discharge leachate to wastewater treatment facilities are likely to see stringent discharge levels for PFAS coming in the future.
Trish Edmond, M.E.Sc., P.Eng. is a Principal and Geo-Environmental Engineer at Golder
Trish has a master’s degree in Geo-Environmental Engineering and has 21 years of experience working on waste management projects in Ontario and Manitoba. Her experience includes new site and expansion approvals, contaminant transport modelling for landfills, leachate quality estimates for treatment system development, assessing groundwater and surface water impacts from landfills and composting operations, waste management plans for small communities, construction and renovation waste management plans and due diligence investigations.
Ryan Schipper, P.E., is Senior Engineer at Golder
Ryan has over 13 years of experience with active and passive treatment projects in North America and overseas. Specializing in wastewater and leachate treatment, projects have involved alternative evaluations, treatability studies, preliminary cost estimates, preliminary design, detailed design, construction oversight, and start-up support.