Removal and Destruction of PFAS and Co-contaminants from Groundwater via Groundwater Extraction and Treatment with Ion-exchange Media, and On-site Regeneration, Distillation, and Plasma Destruction
Nathan Hagelin | Amec Foster Wheeler
The goal of this project is to demonstrate effective integration of a Per- and Polyfluoroalkyl Substance (PFAS) Treatment Train into existing co-contaminant treatment systems. The treatment train includes groundwater extraction and ex-situ removal of PFAS using ion-exchange media, on-site regeneration of the IX media, distillation and reuse of the regenerant solution, and onsite destruction of the distillation waste with enhanced-contact, 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-contaminant treatment system.
- Measure the effectiveness of PFAS and co-contaminant treatment during each treatment step.
- Verify waste minimization through regeneration and reuse of treatment media, concentration of the waste stream, and onsite 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-contaminant treatment systems.
The technology is a four-step process to remove, concentrate, and destroy PFASs: (1) ion exchange (IX) media to remove PFASs from water; (2) IX media regeneration and reuse; (3) regenerant solution distillation and reuse; and (4) onsite destruction of concentrated PFASs 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 cocontaminant 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 onsite PFAS destruction approach using an enhanced contact (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 co-contaminant treatment systems. Success will be measured in terms of PFAS removal efficiency, complete destruction of PFASs onsite, and waste minimization. From the demonstration, a cost model for full-scale implementation and integration into existing co-contaminant 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 PFAS groundwater treatment is granular activated carbon (GAC), which is in wide use at United States Department of Defense (DoD) facilities for drinking water treatment in both public and private/domestic water supply systems. While GAC is effective for removing certain PFASs from groundwater, the PFAS Treatment Train offers superior removal efficiencies for most PFAS compounds with the benefit of onsite regeneration, reuse, and PFAS destruction versus offsite reactivation, disposal, or incineration of spent GAC.
The PFAS Treatment Train represents a significant potential cost savings for DoD. Application at just 25% of the 600+ identified DoD PFAS sites could save DoD $37.5M annually. Wurtsmith Air Force Base (AFB) and Pease ANGB were used to model the cost savings calculation. At Wurtsmith AFB, a 250-gallon GAC system is used to treat PFASs. The annual cost of operations and maintenance (O&M) for that system, driven primarily by the cost of GAC change-outs, is understood to be $500K. At Pease ANGB, the Principal Investigators (PIs) estimated a 50% savings in annual O&M using regenerable IX compared to GAC. A 50% O&M savings applied across 150 sites results in annual potential savings of $37.5M. In addition, onsite destruction with plasma would almost eliminate waste management and disposal costs as well as potential offsite environmental liability.