Destruction of PFAS and Organic Co-Contaminants in Water and Soil Present in Investigation-Derived Waste at DoD Sites Using Novel Adsorbent and Ultrasound
Hui (Lisa) Yu | Amriton LLC
There are many Department of Defense (DoD) sites where groundwater is contaminated with per- and polyfluoroalkyl substance (PFAS). Investigation of PFAS contaminated sites results in investigation-derived waste (IDW). The IDW is a mixture of soil, purge water from groundwater sampling, and fluid from decontamination of drilling equipment, and likely to have PFAS and other co-contaminants. It is desired to develop treatment technologies that can destroy PFAS and co-contaminants in IDW so that the IDW does not have to be landfilled and future liability is avoided.
The broad objective of this research is to develop an innovative, low cost, simple to use, technology for the removal and destruction of PFAS and organic co-contaminants from IDW containing groundwater and soil at DoD sites. Both, the contaminated water and soil will be cleaned and applicable for on-site discharge. No secondary waste stream will be generated. This will be of particular interest to DoD remedial project managers and regulatory professionals.
Overall, the technology uses a three-step approach for PFAS and co-contaminant destruction for soil and water in IDW:
(i) Removal of PFAS and co-contaminants from contaminated groundwater using a novel, low cost adsorbent,
(ii) Desorb the contaminants from the adsorbent with a chemical (regenerant) solution, and
(iii) Destroy PFAS and other co-contaminants in the regenerant solution and those sorbed on soil using ultrasound in one reactor.
The novel adsorbent will be mixed in the IDW tank to remove PFAS and co-contaminants. The adsorbent and soil will be filtered out and the treated water will be discharged. The contaminants sorbed on the adsorbent and soil will be desorbed and destroyed using ultrasound in one reactor. The iron based adsorbent is separated from the slurry using magnets and reused. This project will perform experiments on adsorption, desorption and destruction using ultrasound, and provide a proof of concept for the above described technology.
Both, the contaminated water and soil particles are decontaminated, and PFAS and organic co-contaminants are destroyed by ultrasound in the same reactor. With the suggested approach, the contaminants are removed and concentrated so that the decontaminated water can be discharged. The iron based, polymer coated, reusable adsorbent is separated from the slurry using magnets. The concentrated contaminants and the trapped soil are then cleaned by ultrasound. The ultrasound process can destroy organics such as (PFAS, Trichloroethylene, Tetrachloroethylene, etc.) in water and can also clean the soil in the same operation. This proof of concept project will lead to the development of a very simple, low cost, small foot print, easy to operate treatment system having primarily a PVC tank for IDW, small filter, magnet, pH controller, and a small ultrasound reactor. It will be applicable to al DoD sites where PFAS related IDW is generated. (Anticipated Completion - January 2021)