Bioretention Basins and Buffer Strips for PFAS Reduction/removal

Stormwater practices are used to treat water running off from impervious and pervious surfaces. This presentation will provide data from research being conducted at the University of Georgia using stormwater practices to remove PFAS chemicals from storm induced runoff from land application systems where treated wastewater effluent is applied as a means of final disposal. Results include a 95% reduction of PFOS when soil is used as the media accepting runoff in these stormwater practices.

Full Abstract: Per- and Polyflouralkyl substances (PFAS) have been around since the 1930’s and are used in many different commercial, industrial, and residential applications. Some of these include fire fighting foams, non-stick surfaces, waterproofing and similar type uses. These chemicals can enter water and wastewater treatment systems through many different paths. These include but are not limited to runoff from surface where foam has been applied, through the liquid flushed down the drain in commercial and residential locations where waterproofing or non-stick surfaces are cleaned. Once in the drain system these chemicals can end up entering wastewater water treatment plants (WWTP) for treatment. In some locations WWTP, use land application systems (LAS) as a means of final disposal of the treated wastewater. Our lab has been researching ways to remove PFAS from storm induced runoff from these LASs. Research involved various bioretention mixes and buffer zones. Bioretention mixes ranging from 100% soil and 0% sawdust to 0% soil and 100% sawdust was exposed to a PFAS solution and removal percentages were measured in column studies. Data indicates that 33 to 95% of PFOS can be removed with a Tifton soil and sawdust mixture. The other five PFAS used in the study will be shared. The results provide some indication that bioretention mixes can be used in edge of field practices to remove PFAS from storm induced runoff. A second aspect of the research dealt with the effectiveness of buffer strips to remove PFAS from storm induced runoff. Results indicate that based on the number of Carbons in the PFAS, the buffers can retain these compounds.