Formatted Title
Defining the Scale and Complexity of the Per- and Polyfluoroalky Substances (PFAS) Problem in Solid Waste
Background/Objectives
PFAS in waste presents an enormous challenge for regulators who have responsibility to protect the environment and human health. Priority has historically been given to manage PFAS at contaminated sites, however PFAS inventory from manufacturing industries indicate significantly more PFAS has been produced for use in consumer/engineered articles which end up in landfills, compost facilities or WRRF/STPs, as compared to PFAS previously used in AFFF concentrates for fire-fighting training and emergency response purposes. Therefore, PFAS in solid waste should likewise be prioritized for the significant and complex risk it poses to environment and human health when passing through passive receivers such as transport, handling and disposal networks, often untreated, resulting in the creation of secondary PFAS-impacted waste (e.g., leachate, wastewater, sludge and biosolids) followed by broad dispersal as recycled media and/or approved discharge to final receptors. Air emissions, uptake into food chains, improper disposal of lithium ion batteries and the existence of pervasive ‘PFAS Waste Loops’ represent expanding concerns for PFAS arising from waste management processes.
Approach/Activities
We present a new ‘PFAS Waste Maze’ to visualize the scale and complexity of how solid waste is transformed into secondary waste mediums including fate and transport routes that shift past, present and future PFAS chemistries from one location to another, and we question if current CSM/HHERA modelling adequately considers these secondary waste concerns. Also, what is solid waste? Should it include green waste, municipal and industrial trade wastewaters (both containing solids), traditional wastes comprising putrescible, commercial/industrial (C&I), construction/demolition/debris (C&D/D) wastes and contaminated soils? Do we need to review past contaminated soil and exhausted treatment media volumes disposed to landfills that assumingly would have introduced higher concentrations of PFAS risk to traditional solid waste all reporting into landfill leachate and onwards through the PFAS Waste Maze? If the answer is yes, then new technologies identified by ITRC (October 2023) as potential solutions required have never been more important than now.
Field trial and remediation applications of the proprietary process Surface-Active Foam Fraction (SAFF®) is one leading technology with proven success at scale in landfill leachate settings. The SAFF® process comprises a primary fractionation stage which can be optimized to remove target PFAS to meet trace treatment criteria, secondary and/or tertiary PFAS waste enrichment stages to produce a final PFAS waste concentrate suitable for pairing with third-party destruction cell technologies. Hao (October 2023) reports important process-chemistry harmonization details for evaluating SAFF® process' secondary/tertiary foamate from a groundwater site paired with a bench-scale sub-critical water oxidation cell known as Hydrothermal Alkaline Treatment (HALT™), achieves 90% destruction of concentrated PFAS (approx. 1g/l). These results and approach suggest full-scale paired applications at landfills could provide an important treatment/destruction application to reduce PFAS dispersal onto final receptors identified in the PFAS Waste Maze.
Results/Lessons Learned
Recent publications by the Minnesota Pollution Control Agency (MPCA)/ Barr Eng. (2023) and Tolaymat (Sep. 2023) have begun reporting on PFAS inventories and knowledge gaps on a cohort of representative US landfills during 2018-2022. Masoner (2020) makes a compelling argument for treating landfill leachate as a proxy for solid waste with a key finding that PFAS from landfill leachate represented <2% influent by volume, but 18% of PFAS concentration in WRRF/STP influent. Results from these publications are applied to the PFAS Waste Maze flow diagram.
Total PFAS in global circulation is an enormous challenge and requires complementary management alongside contaminated sites with regulatory criteria and a treatment/destruction hierarchy. Most importantly, PFAS passing through passive receivers needs to become the responsibility of everyone to to ensure we remove/destroy these forever and everywhere chemicals.