Seven Habits of Highly Effective PFAS Source Trackers

Abstract Summary

This presentation shares conclusions of Water Research Foundation's (WRF) Project #5082: Investigation of Alternative Management Strategies to Prevent PFAS from Entering Drinking Water Supplies and Wastewater. The study found it critical for utilities to characterize PFAS sources and minimize PFAS contamination of water resources, but they should be ready to address significant loads from domestic wastewater as well.

This presentation will include:
- A review of the importance of characterization of PFAS sources.
- A discussion of how implementing source control can reduce PFAS in a water resource recovery facility's (WRRF's) effluent and biosolids.

Introduction
Utilities are bracing for upcoming regulatory developments and exploring best approaches for monitoring, managing, and treating PFAS. Many technologies have been evaluated for PFAS removal, but effective treatment technologies are expensive. Thus, more research and policy emphasis are needed on preventing PFAS from entering water in the first place. WRF 5082 had the overall goal of developing actionable strategies for effective management of PFAS sources and providing guidance for utilities. In this presentation, the importance of characterization of PFAS sources will be reviewed, and a review will occur on how implementing source control can reduce PFAS in a WRRF's effluent and biosolids.

The goal of WRF 5082 was to develop actionable strategies for effective PFAS sources management for wastewater treatment and water reuse utilities. These strategies were developed by reviewing PFAS source databases, utility surveys of PFAS source control efforts, and conducting thorough PFAS mass balances in the sewersheds. The data and insights from these efforts then informed a guidebook for how utilities can track down and eliminate PFAS sources.

APPROACH AND RESULTS
The guidance developed through WRF 5082 outlines PFAS source control and mitigation in a seven-step process, as shown in Figure 1. These steps include developing a plan for identifying sources, identifying the sources and sampling, interpreting the results, and managing and mitigating sources of concern. The presentation will quickly review these steps and how utility surveys of monitoring, tracking, and mitigating PFAS provided practical information to industrial and municipal utilities for PFAS mitigation. The rest of the presentation will cover examples of how the steps can be utilized. It filled data gaps about the relative importance of different PFAS sources across wastewater, surface water, and groundwater through database analysis and detailed sampling campaigns.

The presentation will start with reviewing the impact of defacto reuse on PFAS concentrations entering wastewater facilities. Two PFAS source identification investigations will be reviewed — the Trinity River in Texas and Las Vegas (Nevada) Wash watersheds. The Las Vegas watershed investigation was a comprehensive mass balance, while the Trinity River investigation relied on the sweetener sucralose as a wastewater indicator. These studies looked at PFAS occurrence upstream and downstream of known wastewater treatment facilities, as shown in Figure 2. The studies identified that WRRF discharges comprised a majority of PFAS in local waterways, and that the artificial sweetener sucralose can be a cheap indicator of PFAS transport and occurrence since sucralose and PFAS are associated with anthropogenic activities.

The presentation will also discuss common sources of PFAS into collection systems and WRRFs. As part of WRF 5082, five wastewater collection systems across the country were sampled to investigate industrial and domestic/commercial PFAS sources, including firefighting and military areas, metal plating and finishing, textile manufacturing, landfill leachate, and airports. Figure 3 shows that, although the concentrations were high in PFAS from these sources, the mass loadings were less than half of what was supplied from domestic and commercial sources. This reiterates the need to understand the loading contribution of different PFAS sources.

The presentation will conclude with more recent data obtained from the Fifth Unregulated Contaminant Monitoring Rule (UCMR5) survey across the United States (US). Our most recent data analysis confirms that PFAS are widely detected in US surface waters, and that the main contributor is defacto reuse. However, the data also indicates that the frequency of PFOA and PFOS detection is decreasing, likely due to their ban in the early 2010s. Shorter chain PFAS are increasing as they are the replacements for PFOA and PFOS. This evolution in dominant PFAS will likely impact treatment strategies since shorter chains are more difficult to remove from wastewater.

Broader Impacts
This presentation is valuable to utilities, consultants, policy makers, and vendors as it reviews the systematic approach to identifying PFAS sources and approaching mitigation. Common industrial PFAS sources are reviewed, and the importance of quantifying industrial versus domestic/commercial sources will be discussed. In addition, current PFAS data from across the US is reviewed and put in context of how it might impact treatment strategies at wastewater facilities.