As a municipal treatment system, GLWA removes conventional pollutants and, to a lesser extent, toxic pollutants prior to discharging into international and other receiving waters, i.e., the Detroit and Rouge Rivers. Current pollutants of concern are PFAS Compounds. Municipal treatment systems like GLWA’s WRRF are presently unable to effectively treat these materials, resulting in their “pass-through” to the receiving streams. GLWA implemented its state-approved PFOS and PFOA minimization program in 2020 and required current sources of PFAS Compounds to develop and implement similar plans and, as appropriate, site treatment systems. Although these measures have thus far resulted in a reduction of PFAS Compounds in the WRRF’s receiving water discharge, the facility continues to experience episodes where it exceeds Michigan’s water quality standards for perfluorooctanesulfonic acid (PFOS). GLWA attributes these fluctuations to an uncontrolled influx of PFAS Compounds from historical and current sources contained within the collection system. Problem - The WRRF observes that the influent concentrations of PFAS Compounds have periodic spikes, most likely attributable to wet weather events. During such events, stormwater contributions and sewer system scouring result in increased loadings to the WRRF. If historical and current sources and areas of contamination in the sewer collection system can be identified and quantified, it may be possible to develop a control strategy that includes wet weather contribution effects to direct regulatory and mitigative options to effectively reduce, control, and eliminate sources of PFAS Compounds, thereby reducing contributions sent through the sewer system to the WRRF. GLWA has selected its Oakwood Sewer District as the proposed location for the study effort. The Oakwood Sewer District is known to have both historical and on-going releases of materials containing PFAS Compounds. The district also has the unique feature that the presence or use of PFAS Compounds can only be attributed to sources of wastewater that are, or were previously located, within the district, therefore streamlining efforts to determine the origin.
