Grant: Alliance Grants

Per- and polyfluoroalkyl substances (PFAS), also referred to as "forever chemicals", are a class of thousands of fluorine-containing chemicals that are present in many consumer products, and are now being found in wastewater. If untreated, the release of PFAS poses a threat to human health and the environment. Currently, there are no effective and reliable treatments for removing PFAS from biosolids, which are the solid waste products from a wastewater treatment plant. This project will develop a process for treatment of biosolids via pyrolysis, which involves heating the substrate to high temperatures in the absence of oxygen. Pyrolysis produces biochar as a solid product, along with gases and vapors which are burned to produce heat to drive the pyrolysis process. During this project, we will acquire biosolids samples from various wastewater treatment plants and pyrolyze them in a pilot plant reactor. The gases and condensable products will be collected and will be analyzed for the presence PFAS. In some cases, thermal treatment of PFAS-containing compounds can create PFAS-containing by-products which may be just as harmful as the original PFAS. Because there are so many different PFAS compounds it can be challenging to detect and quantify all PFAS in the exhaust gas. Therefore, this work will also investigate the use of metal oxides to break down PFAS while capturing the fluorine, creating a safe and stable product while eliminating PFAS. In addition to investigating PFAS destruction efficiency, this work will explore applications for the produced biochar, which is currently being considered for use in construction materials, for soil amendment, in electronic applications, as a catalyst, or for removal of pollutants from wastewater.