Pilot-testing a novel "Concentrate-&-Destroy" technology for 'green' and cost-effective destruction of PFAS in landfill leachate

Per- and Polyfluoroalkyl Substances (PF AS) have been widely used in everyday consumer products. Landfills are the final repository for the PF AS-containing products and wastes, and consequently, one of the major sources of PF AS to the environment. Elevated concentrations of PFAS in leachate have raised concerns regarding disposal of leachate. Yet, cost-effective treatment technologies for PF AS in leachate have been lacking.Building upon a cutting-edge 'Concentrate-&-Destroy' technology (developed by teaming partner Auburn University, US Patent pending 62/452,648), this project aims to pilot-test the technology for cost-effective removal and destruction of PF AS in landfill leachate. The specific objectives are to: 1) carry out laboratory treatability tests to optimize the treatment conditions, 2) pilot-test adsorption and photocatalytic degradation of PFAS in municipal solid waste (MSW) landfill leachate, 3) determine reusability of the material, 4) examine effects of leachate conditions, and 5) conduct a cost-benefit analysis.The technology is based on an innovative adsorptive photocatalyst (Fe/TNTs@AC) synthesized by modifying low-cost activated carbon (AC) with a cutting-edge photocatalyst, iron-doped titanate nanotubes (Fe/TNTs). The technology works by first concentrating PFAS in water onto Fe/TNTs@AC, and then completely degrading PFAS under UV or solar light. Bench-scale studies indicated that Fe/TNTs@AC can remove >99% of PFOA or PFOS from water via adsorption within 1 hour and degrade nearly 100% of the adsorbed PFAS within 4 hours of UV irradiation. Complete destruction of PFOA also regenerates the material, allowing for repeated uses. While conventional AC or resins do not degrade PF AS, and while PF AS-saturated AC or resins are hardly regenerable, PF AS on Fe/TNTs@AC are amenable to efficient photocatalytic degradation, which not only destroys PF AS, but regenerates the material. While direct photochemical treatment of PF AS-laden water is often cost-inhibitive, the new technology employs photocatalytic treatment only for spent Fe/TNTs@AC, which is only a fraction of the raw water volume, and thus consumes much less energy.This project will fill a key technology gap for cost-effectively treating PF AS in landfill leachate. The technology will arm landfill field engineers and decision makers with a cost-effective solution and mitigate the health impacts as the relevant regulations are rapidly evolving. Given the omnipresence of PFAS in MSW landfills, the market potential is huge. Moreover, taking advantage of CTI's expertise in landfill-related projects, this project will greatly facilitate transition of this novel technology to hundreds of the landfill sites.