Insights from the First Foam-Fractionation + Electrochemical Oxidation Treatment System for PFAS Destruction in Metal Finishing Wastewater

Background / Objectives:
The use of per- and poly-fluoroalkyl substances (PFAS) was once mandated for vapor suppression in many metal plating and finishing facilities. Although such use has been discontinued for well over a decade, many of these same facilities are faced with presistant residual PFAS compounds in their process and wastewater streams. Faced with the need to provide effective treatment and reduce operating cost, a midwestern metal plating and finishing operation began work to evaluate and select an onsite treatment and destruction system to address PFAS at several of their existing manufacturing operations.

Approach / Activities:
Tasked with the need to develop an effective way to remove PFAS from its wastewater stream the facility's team successfully developed its own in-house foam-fractionation process capable of achieving the Michigan Department of Environment, Great Lakes & Energy (EGLE) discharge limits for PFAS (<=16 ppt) and PFOA (<=7 ppt). The onsite foam-fractionation process produce a PFAS concentrated foamate that was then passed to an electrochemical oxidation process onsite for PFAS destruction. Pilot testing of the combined process was completed in early 2024 which confirmed that the electrochemical oxidation process could easily achieve 3-log to 5-log destruction of both long- and short-chain PFAS compounds from influent concentrations as high as 73 mg/l.

Results / Lessons Learned:
Based on the successful lab testing and field piloting results, the metal finishing facility chose to install complete PFAS removal and electrochemical destruction processes at several of its existing facilities. Work on the first system commenced with installation of a temporary system to fine-tune overall system performance for the final full-scale system which is scheduled to be complete in mid 2025. This paper will provide an overview of the project from pilot testing through installation of the first commercial-scale foam-fractionation + electrochemical oxidation PFAS destruction system for metal finishing wastewater applications along with along with lessons-learned for future projects.