Schaefer, Charles

Dr. Schaefer is a chemical engineer with over 25 years of experience in the fate, transport, and treatment of organic contaminants in water and soil....

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About Schaefer, Charles

Dr. Schaefer is a chemical engineer with over 25 years of experience in the fate, transport, and treatment of organic contaminants in water and soil. He received his PhD in Chemical & Biochemical Engineering from Rutgers University. Dr. Schaefer currently is the Director of CDM Smith’s Research & Testing Laboratory in Bellevue, WA, overseeing a large number of research projects and treatability studies for federal, municipal, and private sector clients. His recent efforts have focused on fundamental processes related to PFAS migration and fate in the both the subsurface and in wastewater treatment plants, as well as PFAS treatment technologies.

Schaefer, Charles

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Description: Identifying Challenges and Potential Strategies for Mitigating PFAS Based on...

Identifying Challenges and Potential Strategies for Mitigating PFAS Based on Observed PFAS Fate and Transport in Wastewater Treatment Plants

Abstract

Efforts as part of multiple on-going and recently completed Water Research Foundation projects have closely evaluated poly- and perfluoroalkyl substance (PFAS) fate and transport throughout unit processes in wastewater treatment plants (WWTPs) and in finished biosolids. Collectively, these efforts have shown that the majority of PFAS in WWTP influent, effluent, and finished biosolids are precursors that can consist of semi-quantifiable analytes. In biosolids, these semiquantifiable PFAS are dominated by phosphonic acid-based PFAS, including polyfluoroalkyl phosphoric acid diesters (diPAPs). The transformation of these diPAPs to fluorotelomer carboxylic acids and perfluoroalkyl acids often plays an important role in controlling PFAS levels in WWTP effluent and in overall PFAS leaching from biosolids. Aeration and solids dewatering processes in WWTPs also serve as a means for concentrating PFAS in foams/aerosols and dewatering concentrate, respectively, and may serve as an opportunity to mitigate PFAS in WWTP effluents.

PFAS evaluation at multiple wastewater treatment plants (WWTPs) highlighted the prevalence of precursors in both the influent, effluent, and biosolids streams. Specifically, the role of phosphonic acid-based PFAS transformations both during WWTP processes and in finished biosolids was identified as a key mechanism. PFAS migration into foams and aerosols during aeration also was observed. Together, these processes pose challenges, but also may offer opportunities for PFAS mitigation.

SpeakerSchaefer, Charles

Presentation time

13:30:00

13:50:00

Session time

13:30:00

15:00:00

SessionMaking Forever Chemicals Gone Forever

Session locationRoom S405- Level 4

TopicAdvanced Level, Microconstituents and Contaminants of Emerging Concern (Non-PFAS), PFAS, Research and Innovation, Water Reuse and Reclamation

Author(s)

Schaefer, Charles

Author(s)C. Schaefer 1; J. Hooper 2 ; D. Nguyen 3; H. Lanza 3; K. Wu 4; J. Guelfo 4; C. Schaefer 1;

Author affiliation(s)CDM Smith 1; CDM Smith 2 ; CDM Smith 3; CDM Smith 3; Department of Civil, Environmental & Construction Engineering, Texas Tech University 4; Department of Civil, Environmental & Construction Engineering, Texas Tech University 4; CDM Smith 1;

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2023

DOI10.2175/193864718825159092

Volume / Issue

Content sourceWEFTEC

Word count20

Base text size -

Schaefer, Charles

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