18 months with PFAS: Lessons from a California wastewater pilot study

In this interview from WEFTEC 2025, Bob Crossen speaks with Conner Murray, Principal Engineer at Hazen and Sawyer, about an 18-month pilot study conducted in Riverside, California, with Western Municipal Water District. The study focused on PFAS removal in tertiary wastewater effluent and explored a range of treatment strategies to meet stringent regulatory targets.

Murray shares insights into the challenges of high PFAS concentrations, organic matter interference, and media fouling—issues that wastewater utilities across the country may soon face. The conversation highlights the importance of pretreatment, the limitations of traditional adsorption methods, and the need for tailored solutions in wastewater applications.

Key highlights with timestamps

• 00:07 – Introduction to guest and pilot study
• 00:24 – PFAS regulations shifting to wastewater
• 00:45 – Study location and goals
• 01:08 – Adsorption and pretreatment strategies
• 01:32 – Challenges: high PFAS and low treatment targets
• 02:11 – Organic matter complicates treatment 02:43 – Pretreatment improves adsorption performance
• 03:28 – Algae and media fouling issues
• 04:00 – Lessons for other utilities
• 04:16 – Pretreatment is essential
• 04:38 – Shorter media changeout times in wastewater
• 04:54 – Closing remarks and resources 

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