4/7/21 
WEF Kicks Off Webcast Series on PFAS with Session on Biosolids

The Water Environment Federation hosted a webcast on per- and polyfluoroalkyl substances (PFAS) in municipal biosolids on April 1st. This was the first of three webcasts by WEF which recently established a new PFAS Task Force to focus on PFAS in water issues and collaborate activities across all WEF Committees. NEBRA’s own Ned Beecher was co-moderator with Maddy Fairley-Wax, P.E., of Jacobs for this first webcast. Mr. Beecher started the webcast with a presentation on recent PFAS developments and potential municipal impacts which set the stage for the rest of the webcast. On PFAS, Mr. Beecher said of PFAS, “Once considered contaminants of emerging concern, PFAS have now truly “emerged” as worrisome contaminants in the regulatory and scientific communities.” He also pointed out that “while management and mitigation actions have significant positive effects, ultimately we cannot clean up our way out of the PFAS problem.” He stressed that the feature of any good PFAS mitigation program is source reduction and he cited Minnesota’s PFAS Blueprint as a good example.

Next, Dr. Linda Lee of Purdue University presented information from her studies of PFAS in biosolids and compost products applied to land. She reviewed the issue of PFAS “biodegradability” which is the term she used to describe the transformation of perfluoroalkyl acids (PFAA) “precursors” to “terminal products” such as the very stable carboxilic and sulfonic acids forms which are persistent and more soluble and mobile than the precursor compounds. Dr. Lee presented research showing that aerobic processes increase the concentrations of short-chain and precursor compounds – much more so than anaerobic processes used for solids stabilization.

Dr. Lee has also been studying the pyrolysis process and how that impacts PFAS in the environment. Pyrolysis of biosolids leads to volume and mass reduction and reduction in “most (not all) PFAA concentrations” but it may still be in syngas. Dr. Lee’s research has shown that the varied properties of different biosolids may affect PFAS release – things like aluminum and iron content, pH, and percent organic matter – as well as polymer additions in the treatment process. Following Dr. Lee, Jason Prevatt of Pima County (Arizona) Regional Water Reclamation Department gave a presentation about their PFAS groundwater contamination study which NEBRAMail previously reported on in December of 2020.

The last presentation in the webcast was by Mike Person, the State Biosolids Program Coordinator for the Michigan Department of Environment Great Lakes and Energy (EGLE). Mr. Person spoke about the State’s interim strategy for managing land application of biosolids containing PFAS. Mr. Person gave attendees a preview of the detailed report that is expected out very soon as a follow-up to the June 2020 summary report titled “PFAS Initiatives to Evaluate the Presence of PFAS in Municipal Wastewater and Associated Residuals (Sludge/Biosolids) in Michigan” which includes Michigan’s draft interim land application strategy.

The interim strategy includes continued sampling of biosolids for PFAS. EGLE has complied the testing results to date, finding an average PFOS concentration (for example) across all biosolids to be about 18 µg/kg (or parts per billion, ppb). EGLE has also established a screening level of 150 ppb, what EGLE considers industrially-impacted biosolids. Facilities generating biosolids with 150 ppb or greater of PFAS will not be allowed to land apply that material and will be required to do additional wastewater sampling and develop a source reduction program. For biosolids with PFAS concentrations between 50 ppb and 150 ppb, facilities will be required to immediately notify EGLE, sample their effluent, and develop or implement a source reduction program. These biosolids will be subject to reduced application rates or an alternative risk mitigation strategy developed in conjunction with EGLE. Finally, for biosolids with PFAS concentrations below 50 ppb, EGLE is still recommending additional sampling and source identification if the results are greater than 20 ppb.

In its investigations to date, EGLE has found higher concentrations on historic land application sites where the biosolids were deemed industrially impacted but did not find significant wide scale groundwater impacts at these sites. However, EGLE did find elevated concentrations in surface water at these sites. Based on the ELGE data, the PFAS source reduction efforts have been very successful in making significant reductions in PFOS concentrations in wastewater and biosolids. For more information about Michigan’s efforts, check out the Michigan PFAS Action Response Team (MPART)’s Land Application Workgroup website.

WEF continues its focus on PFAS with additional webcasts on April 29th (Detection and Source Identification Approaches of PFAS) and May 27th (PFAS in Water Reuse).

This article was updated on April 9, 2021.