PFAS at Wastewater Treatment Facilities and Landfill Leachate

PFAS collection, analysis and assessments

Weston & Sampson, on behalf of the VTDEC, performed sampling and analysis of landfill leachates; WWTF influent, effluent, and sludge; and septage at several WWTF and surface water at various facilities for the presence of per- and poly-fluoroalkyl substances (PFAS). The study was to determine the contribution of landfill leachate to influent and effluent concentrations of PFAS at WWTFs and to assess the potential for PFAS contributions to the environment from WWTFs. We assessed the variability of PFAS concentrations in leachate and WWTF related media by collecting leachate samples during 8 rounds of sampling from 4 landfills. WWTF influent, effluent, sludge, and/or septage samples were collected from 30 individual facilities for totals of 124 influent, 136 effluent, 75 sludge (sludge, Class A and Class B combined), and 5 septage samples. Surface water samples were also collected upstream and downstream of the Montpelier WWTF outfall. The samples were analyzed for 24 PFAS compounds using a proprietary method, including PFHxS, PFHpA, PFOA, PFOS, and PFNA.

The data indicated that PFAS are present in all landfill leachate and WWTF influent, effluent, and sludge tested and PFAS concentrations are greater at facilities handling landfill leachates, frequently above regulated PFAS concentrations. It will require more analysis to determine landfill leachate impacts on sludges due to sludge makeup variability; however, the reduction in PFAS concentrations between WWTF influent and effluent samples implies that sorption to sludges.

The final report was provided the VTDEC and approved in early 2020. The study’s work and conclusions will inform a number of our projects related to WWTF sludge management, anaerobic digestion feasibility studies, and NPDES permit negotiations.

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Posted in Emerging Contaminants, Environmental Consulting, Industry-Municipal, Wastewater, WWTreatment and tagged .