[REPORT] Initiatives to Evaluate the Presence of PFAS in Municipal Wastewater and Associated Residuals (Sludge/Biosolids) in Michigan

By Michigan Department of Environment, Great Lakes, & Energy
June 24, 2020

In 2018 the Michigan Department of Environment, Great Lakes, and Energy (EGLE), Water Resources Division (WRD), implemented two initiatives to assess potential environmental impacts of Per- and Polyfluoroalkyl Substances (PFAS) associated with municipal wastewater. The first initiative, the Industrial Pretreatment Program (IPP) PFAS Initiative, was launched in February 2018. The purpose of the IPP PFAS Initiative was to evaluate the potential for PFAS from industrial sources to pass through wastewater treatment plants (WWTP) to receiving waters (groundwater, lakes, and streams), and to reduce or eliminate significant industrial sources of PFAS to the municipal system, if found. The initiative was based on existing federal and state regulations and was implemented by 95 municipal WWTPs utilizing existing control authorities developed under their approved IPPs. During the IPP PFAS Initiative, Perfluorooctanoic Acid (PFOA) was not detected above state water quality values in any WWTP effluent. As a result, Perfluorooctane Sulfonic Acid (PFOS) has become the main regulatory driver for PFAS control. Two years into implementation, of the 95 WWTPs with IPPs, 46% did not identify any significant industrial sources of PFOS or PFOA to their system, 23% identified significant industrial sources but the WWTP discharge still meets state water quality values, and 31% identified significant industrial sources and the WWTP discharge exceeds state water quality values. In addition, there is significant evidence to support that utilizing the established authorities under the IPP to identify and control industrial sources of PFAS (specifically PFOS) to WWTPs is highly effective at reducing the discharge of this pollutant into the environment from WWTP discharges. The WRD launched a second initiative in the fall of 2018. Under this initiative, a study of 42 municipal WWTPs was conducted to evaluate the presence of PFAS in influents, effluents, and associated residuals (sludge/biosolids) generated at the facilities. As part of this initiative, screening of 22 land application sites was conducted to further understanding of the potential impacts to the environment from land-applied biosolids. For this study, the WRD contracted with a consulting firm, AECOM Technical Services, Inc., to perform sampling at the WWTPs and land application field sites. Samples were analyzed for 24 PFAS compounds. Initial findings from the study found that PFAS were frequently detected in municipal wastewater, residuals, and at land application sites where biosolids were applied. Concentrations in residuals were similar or lower than concentrations identified in previous studies in the United States and other countries with industrial sources. Through implementation of the IPP PFAS Initiative and the statewide study, WRD was able to identify 6 WWTPs with high PFOS concentrations in their WWTP discharge and biosolids/sludge and temporarily restrict land application from those facilities until sources of PFOS are controlled and concentrations in the residuals decrease. Screening of agricultural fields that received biosolids applications found significantly lower PFAS concentrations in various environmental matrices (soils, surface waters, etc.) associated with WWTPs with lower levels of PFAS in their biosolids as compared to those with elevated levels. This document provides a brief summary of the status and findings of these two initiatives. A more comprehensive report that provides additional information and analysis of the initiatives and results from the field screening is expected to be released later in 2020.