2020 Project: Sewershed-scale analysis of perfluorinated compounds in wastewater from domestic, commercial, and industrial sewerage system users

Project Overview:

Partners: Orange County Water District, Irvine Ranch Water District, Santa Margarita Water District, Moulton Niguel Water District, Orange County Sanitation District, Eastern Municipal Water District, Western Municipal Water District, Inland Empire Utilities Agency, San Bernardino Valley Municipal Water District

Project period: One year beginning in September 2020

Introduction: Per- and polyfluoroalkyl substances (PFAS) are synthetic chemicals that have been widely used in consumer and industrial products since the 1940s due to their hydro/oleo-phobicity. Some of the PFAS ingested via these products is eliminated though urine and feces, which introduce PFAS into the municipal wastewater stream. PFAS may also be released into raw wastewater from textiles during laundering, and from use of PFAS- containing personal care products. Although a few studies have quantified the PFAS content of a few consumer products, the actual contribution of households to the load of PFAS in raw wastewater is currently unknown. In addition to residences, commercial (such as dry cleaning and laundromats) and industrial users of the sewerage system may also contribute PFAS to the influent of a wastewater treatment plant (WWTP). The amount of PFAS, and the major products or processes leading to high release of PFAS, from commercial and industrial operations into raw wastewater are not currently known. Upstream and downstream strategies to decrease PFAS concentrations in the wastewater stream require an understanding of the PFAS flux originating from different users of the sewerage system.

The objectives of this proposed project are to: (1) develop a methodology to identify the sources of PFAS in the sewershed of a WWTP in Orange County; one that can be replicated elsewhere for PFAS or other contaminants; and, (2) work with a WWTP selected by the Industry Advisory Board (IAB) to implement the methodology, with the goal of identifying the primary sources of PFAS to the Plant’s sewerage system. Additional studies will be conducted to identify specific products leading to large PFAS release.

Samples will be collected from the conveyances (sewer lines) upstream of the WWTP headworks, WWTP influent, treatment units, and effluent.  Sampling will be iterative with each phase dependent on the findings of the last and in consultation with the project partners.  Samples will also be collected in sewerlines connected to residences (including greywater and blackwater), commercial operations, and industries within the sewershed of the selected WWTP.  Additionally, samples will be collected from inside these potential sources as warranted (i.e., if a large amount of PFAS is seen in residential neighborhoods, individual residences will be sampled).  A total of ~750 samples will be analyzed for 17 commonly detected PFAS (including the perfluoroalkyl acids detected in drinking water wells in California). The data obtained will be used to quantify contributions of PFAS from sewerage users to the wastewater stream, identify specific products/processes leading to large PFAS releases, and investigate patterns in PFAS composition from different sources (residential, commercial, and industrial).