The overall technical objective of this demonstration is to provide a proven and sustainable solution to cleaning per- and polyfluoroalkyl substances (PFAS) out of firefighting delivery systems. The process will include the use of PerfluorAd as a functional precipitate (Cornelsen and Verena, 2018) to enhance the cleanout of the delivery system and reduce the volume of water required to reach a desired endpoint. The rinsate produced will be further treated with PerfluorAd as necessary to maximize PFAS removal from the rinsate. The small volume of concentrated filtrate will then be subject to further destruction or offsite disposal.
The specific technical objectives include the following:
- Demonstrate enhanced cleaning of a laboratory surrogate system with residual aqueous film forming foam (AFFF)
- Reduce volume of waste requiring disposal or expensive destruction
- Increase PFAS removal effectiveness from AFFF delivery systems
- Determine optimal PerfluorAd dosage
- Demonstrate effective rinsate treatment using PerfluorAd (with optional polishing)
- Demonstrate solution using a government-furnished Aircraft Rescue and Firefighting Vehicle
- Assess life cycle costs and sustainability
- Assuming all objectives are met, facilitate technology transition by developing a recommended general procedure for applying the technology, including any necessary treatability studies for different systems
The aforementioned objectives will be achieved through the use of a total solution for cleaning out AFFF-containing firefighting delivery systems. The solution consists of removal of residual PFAS from the system; separation of PFAS from the rinsate and concentration of the PFAS using PerfluorAd, a biodegradable liquid that interacts almost exclusively with PFAS to form flocculants that can be removed via filtration or sedimentation.
The current practice of cleaning out firefighting delivery systems with triple water rinse is inadequate in removing residual PFAS and generates a large volume of PFAS-impacted waste that also requires disposal or treatment, which is extremely inefficient, if not impracticable, using conventional technologies. Unlike other approaches, the use of PerfluorAd in the application of cleaning out firefighting vehicles has been demonstrated successfully at a commercial scale in Germany, making it a low-risk technical solution for the Department of Defense (DoD). Besides the PerfluorAd itself, no other proprietary materials or equipment will be required for field-scale implementation. With proper optimization, a mobile system can be used in the very near future at multiple DoD installations for cleaning firefighting delivery systems in a low-cost, sustainable manner with little waste. If successful, this approach should also be transferable to cleaning out AFFF fire suppression systems such as those in hangars, or other DoD facilities.