We Believe The World Needs Better Ways To Treat PFAS
Challenge
In Portsmouth, NH, it was discovered that there was PFAS contamination at the Pease Air Force Base (AFB). Due to this, a plume had migrated off-site towards the three nearby drinking water supply wells, therefore contaminating the water at the Pease Public Water System. These three wells, the Harrison, Haven, and Smith, supplied drinking water to 10,000 people that live and work in the nearby area. The Haven well in particular was heavily impacted with PFAS, with groundwater concentrations exceeding 2.4 μg/L. The Haven well was removed from service, forcing system operators to rely heavily on the Harrison and Smith, while receiving supplemental water from the neighboring Portsmouth water system.
Solution
Initially, a 400 gallon per minute (GPM) demonstration was conducted by the city and funded by the Air Force Civil Engineering Center (AFCEC). Full-scale temporary Granular Activated Carbon (GAC) filters were installed on the combined discharge to remove the relatively low levels of PFAS (PFOS +PFOA < 70 ppt) from the remaining two wells.
Later, ECT2 was hired to participate in a pilot study on Haven well. The goals of this study were to compare the lifecycle cost of ion-exchange (IEX) resin to the traditional method of GAC. This three-month pilot-scale test was installed and operated on site, and later provided a full data evaluation report.
ECT2’s pilot study consisted of the following three objectives:
- Compare the ability of ECT2’s resin with GAC
- Confirm system sizing and design parameters to be used in preparation of the full-scale treatment system design
- Confirm projected operations and maintenance costs
Result
The pilot study’s 20-year lifecycle cost comparison discovered that the GAC would result in requiring more frequent changeouts, a larger building, and larger vessel sizing in comparison to IEX resin. Furthermore, IEX resin significantly outperformed GAC, including the ability to remove short-chain compounds more efficiently. After reviewing the data, the city and AFCEC agreed that the IEX resin was the best option, especially considering their desire to future proof in case of potential short chain PFAS regulations being implemented at a later date. ECT2 was retained to design and fabricate a full-scale resin system and delivered the project on-time and on budget. Full-scale operations have continued since 2021 with 100% compliance for all NHDES regulated compounds (PFHxS, PFOS, PFOA, and PFNA) for the NSF-61 certified drinking water system.
Innovation, Partnership Brings Pease Water Treatment Plant Online
On May 4, 2021, a ceremony was held at the former Pease AFB to mark the opening of the state-of-the-art water treatment facility to help protect the community’s drinking water supply. In attendance were:
- Rick Becksted, Mayor, Portsmouth NH
- Brian Goetz, City Deputy Director, Public Works
- Chris Pappas, US Representative
- Maggie Hassan, US Senator
- Andrea Amico, Co-Chair, Pease Restoration Advisory Board
- Jeanne Shahee, US Senator
- Jennifer Miller, Acting Secretary, Air Force Energy, Installation and Environment
You can read the full press release from AFCEC by clicking here.
