Removal and Destruction of PFAS and Co-Occurring Chemicals from Groundwater via Extraction and Treatment with Ion Exchange Media, and On-Site Regeneration, Distillation, and Plasma Destruction
Nathan Hagelin | Wood
The goal of this project is to demonstrate effective integration of a per- and polyfluoroalkyl substance (PFAS) Treatment Train into existing groundwater treatment systems. The treatment train includes groundwater extraction and ex situ removal of PFAS using ion exchange (IX) media, on-site regeneration of the IX media, distillation and reuse of the regenerant solution, and on-site destruction of the distillation waste with enhanced-contact (EC), low-energy plasma. Specific technical objectives include:
- Develop a general technical approach to integrate the PFAS Treatment Train into existing groundwater treatment systems.
- Implement this technical approach at a field demonstration site with an existing co-occurring chemical treatment system.
- Measure the effectiveness of PFAS and co-occurring chemical treatment during each treatment step.
- Verify waste minimization through regeneration and reuse of treatment media, concentration of the waste stream, and on-site PFAS destruction.
- Based on field performance, develop guidance regarding applicability and limitations, anticipated performance, design considerations, operation and maintenance procedures, and costing for integration of the PFAS Treatment Train into existing co-occurring chemical treatment systems.
The technology is a four-step process to remove, concentrate, and destroy PFAS:
- IX media to remove PFAS from water;
- IX media regeneration and reuse;
- Regenerant solution distillation and reuse; and
- On-site destruction of concentrated PFAS in the distillate residue by a low-energy electrical discharge plasma process.
Collectively, the process, hereafter referred to as the PFAS Treatment Train, can be integrated with existing groundwater treatment systems. The first three steps have been demonstrated at pilot scale and a full-scale system that includes the first three steps is under construction at Pease Air National Guard Base (ANGB). The on-site PFAS destruction approach using an EC electrical discharge low-energy plasma reactor is novel and has been demonstrated to be effective in the laboratory at Clarkson University. Field-scale demonstration will be conducted to validate the PFAS Treatment Train and its ability to be integrated into existing groundwater treatment systems. Success will be measured in terms of PFAS removal efficiency, complete destruction of PFAS on site, and waste minimization. From the demonstration, a cost model for full-scale implementation and integration into existing groundwater treatment systems will be developed, along with technical guidance for selection, optimization, integration, and implementation of the PFAS Treatment Train.
The current most commonly employed technology for treatment of PFAS-impacted groundwater is granular activated carbon (GAC), which is in wide use for drinking water treatment in both public and private/domestic water supply systems. While GAC is effective for removing certain PFAS from groundwater, the PFAS Treatment Train offers superior removal efficiencies for most PFAS with the benefit of on-site regeneration, reuse, and PFAS destruction versus off-site reactivation, disposal, or incineration of spent GAC.
The PFAS Treatment Train represents a significant potential cost savings. A 50% operation and maintenance savings applied across 150 sites results in an annual potential savings of $37.5M. In addition, on-site destruction with plasma would almost eliminate waste management and disposal costs as well as potential off-site environmental liability.