Cutting Edge Technologies for PFAS Removal from Groundwater and Leachate
Landfill leachate is coming under increasing scrutiny as a conduit for discharge of PFAS to POTWs or through direct discharge. Although drinking water guidelines and standards are much lower than wastewater or leachate limits (if any), the direction is worrisome for landfill managers. Constituent concentrations are regulated at increasingly lower levels, such as:
- New Jersey adopted MCLs of 13 and 14 ppt for PFOS and PFOA, 13 ppt for PFNA;
- MI Guidelines are PFOA: 9-ppt; PFOS: 16-ppt; PFNA: 6-ppt; PFHxS: 51-ppt; PFBS: 420-ppt and GenX370 ppt
- New York is PFOA and PFOS MCLs of 10 ppt;
- Connecticut drinking water guidance is 70 ppt for sum of PFOA, PFOS, PFNA, PFHxS and PFHpA;
- Vermont has Groundwater Quality Enforcement Standard of 20 ppt f PFOA, PFOS, PFNA, PFHxS and PFHpA;
- New Hampshire NHDES has MCLs and Ambient Groundwater Quality Standards of 15 ppt for PFOA; 12 ppt for PFOS; 23 ppt for PFNA; and 85 ppt for PFHxS;
- Minnesota limits drinking water of 70 ppt for PFOS, 38 ppt for PFOA;
- North Carolina has a Health Advisory of 140 ppt of PFAS GenX.
- California is 6.5 ppt for PFOA and 5.1 for PFOA
These standards lead to confusion for drinking water limits, as well as uncertainty for the impact of sewage sludge deposited in landfills and the implications of leachate generated from the sludge applications that end up in the leachate that may eventually contaminate drinking water supplies.
Existing technologies for removing PFAS from a liquid flow include activated carbon, ion exchange, and reverse osmosis. The concerns with these technologies include residuals management, as these technologies are separation approaches instead of contaminant destruction. Further, residuals management may transfer more concentrated fractions to solid waste and air media.