Removing PFAS from drinking water sources poses many challenges owing to the sheer diversity of different PFAS compounds and co-contaminants that can be present. No two treatment solutions are the same. PFAS concentrations can be dominated by long-chain species at one site and short-chain at another, while other sites may contain a mixture of the two— including many kinds of each.
We start with characterizing PFAS compounds and their concentrations in the source water with precision and accuracy well above that of the standard EPA method 537.1. Our Method Reporting Limit (MRL) of 2 ng/L (ppt) for all analytes and detection limits at 0.2 ng or below, (depending on analyte) help measure rates of removal of the various analytes.
In a pilot scale study to assess performance of 2 different Granular Activated Carbons (GAC) and 2 Ion Exchange Resins for well water contaminated with AFFF, we were able to show that the short chain PFAS breakthrough the treatments faster than the long chain PFAS. We could distinguish and quantify branched to linear isomer ratios and showed that the branched isomers breakthrough faster than linear isomers. Our detailed analysis provided guidance on the types and combinations of treatment product or design of treatment trains.
We have an ongoing project to support pilot scale evaluation of 4 PFAS treatment products under development by a leading vendor at a Delaware Public Water supply system. The water in the area where the wells are located is thought to be contaminated with PFAS from fire-fighting operations. The Center for PFAS Solutions will analyze the influent and effluent water at regular intervals to generate data to compare the performance of the 4 sorbents. In addition, we are able to identify isomeric profiles (branched and linear isomers), and other structural features of the PFAS contaminants in the influent and effluent. By combining this information with our knowledge of the chemistries of PFAS, the history of PFAS production processes (electrochemical fluorination and telomerization), we aim to shed some light on the source of contamination.
