Hooper, Jennifer, Hooper

Ms. Hooper is a professional engineer with 16 years of experience. She recieved her M.S. from Cornell University in Environmental Engineering and is...

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About Hooper, Jennifer

Ms. Hooper is a professional engineer with 16 years of experience. She recieved her M.S. from Cornell University in Environmental Engineering and is currently pursuing a PhD from the University of Washington in Civil and Environmental Engineering. She is working part-time as a Principal at CDM Smith where she focuses on emerging contaminants, innovative treatment technologies and applied research.

Hooper, Jennifer

Titles from this speaker

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

Description: Occurrence of Poly-and-Perfluoroalkyl Substances in United States Water Resource...

Occurrence of Poly-and-Perfluoroalkyl Substances in United States Water Resource Recovery Facilities

Abstract

Learning Objectives:
1. Understand the occurrence of PFAS at US water resource recovery facilities (WRRFs)
2. Understand typical temporal fluctuations
3. Understand partitioning behavior and role of precursors through of treatment.
Introduction
The presence of poly- and perfluoroalkyl substances (PFAS) in water resource recovery facilities (WRRFs) has been widely reported. However, comprehensive quantitative data on specific PFAS compounds, their fate and phase partitioning through WRRF treatment processes, and the factors that control PFAS distribution in finished biosolids compared to the effluent outfall remain poorly understood. The absence of this fundamental information is a critical barrier for utilities to effectively manage and respond to a rapidly evolving public perception and regulatory climate related to PFAS. A significant body of research on PFAS fate and transport in the environment has accumulated in recent years and many of these recently developed tools and insights can be leveraged to investigate much-needed information specific to WRRFs.
Status:
Sampling has been completed. Results have been compiled for the occurrence survey at 38 WRRFs and temporal variability assessment at 14 WRRFs. The detailed mass balance assessment at 9 WRRFs has been conducted and data analysis is currently underway.
Methodology:
Thirty four utility partners representing 38 facilities were involved spanning most US geographies and climates. In the first phase of the study, these 38 facilities collected 24-hour flow-weighted composite samples from the WRRF influent and effluent, in addition to a single-point biosolid grab sample. Samples were collected by the facilities following strict quality control procedures and adhering to US EPA SOP EMAB0113.01. For the second phase of the study, 14 facilities continued to sample their influent and effluent on a monthly basis and their biosolids quarterly for 12 months. Samples were analyzed for 32 target and 1,500 suspect compounds using high HPLC-QToF-MS/MS with a mass spectral library (6,7,8). Analytical replicates were conducted in duplicate for 80% of the samples and triplicate for 20% of the samples. In addition to the PFAS data analyzed, utilities provided information regarding their treatment processes and process flow diagrams, historical flows, collection system point source dischargers, and water and solids quality data on the day of sampling. Finally, a detailed mass balance investigation was conducted at 9 WRRFs to characterize PFAS partitioning through various unit processes through treatment. This included influent, primary treatment, secondary treatment, effluent and biosolids at the 9 facilities, as well as additional treatment trains specific to each facility. Aqueous, solids, colloidal and volatile PFAS samples were collected and analyzed for 32 target PFAS compounds, total oxidizable precursors, and/or extractable organic fluorine.
Findings:
The sum of target PFAS in the influent and effluent samples typically ranged from 50 ng/L to 250 ng/L, though a couple outliers had concentrations greater than 500 ng/L (Figure 2). The sum of target PFAS was not significantly higher in the influent samples relative to the effluent samples (t(74) = 0.797, p = 0.427). Wastewater effluents were generally enriched in perfluorinated carboxylic acid (PFCAs) relative to the influent, and, in particular, short chain (C4-C6) PFCAs. PFCAs are known preferential degradation products from PFAA precursor compounds (2). Precursor concentration largely decreases between influent and effluent samples. For example, 6:2 fluorotelomer sulfonamide (FtS) was a precursor that was present at the highest concentrations at the influent and effluent samples and was largely responsible for this discrepancy. As shown in Figure 3, biosolids were enriched with precursors when compared to influent and effluent samples, suggesting that there is potential for transformation of precursors once biosolids are land applied. Notably, long chain PFAAs were present at higher concentrations than short chain PFAAs in biosolids. This is likely due to longer chain PFAAs being more strongly associated with solids due to hydrophobic interactions of the longer perfluorinated carbon chain relative to short chain PFAAs. To further examine the fate of target PFAS detected in WRRFs, PFAS mass loading expressed as fluoride was calculated for each facility based on influent and effluent flowrates on the day of sampling and average annual biosolids production. The results presented in Figure 3 suggest that the majority of target PFAS leaving WRRFs were associated with the aqueous effluent, rather than partitioning into biosolids. Sixteen WRRFs had an increase in total detected PFAS in the effluent relative to influent. PFCA concentrations generally increased in the effluent as opposed to the influent, while precursors decreased in the effluent. Transformation of precursors into short chain PFCAs might be a key element in the efforts to close mass balance of PFAS in these WRRFs. For example, at Facility 38, 29,640 mg/day of 6:2 FtS entered the influent, but only 33% (9,710 mg/day) was detected in the effluent and none was detected in the biosolids, suggesting precursor transformation occurred. Relatively, low mass concentrations of the C4 to C6 PFCAs (e.g., PFBA, PFPeA and PFHxA) were observed in the influent (8,340 mg/day), but the total mass for these compounds more than doubled in the effluent (17,609 mg/day). However, the decreased concentration of 6:2 FtS in the effluent did not appear to solely account for the mass of short chain PFCAs present in the effluent. Other precursors including fluorotelomer carboxylic acids (FTCA) and other suspect analytes were detected that may have contributed to the increased PFCAs. FTCAs are precursor compounds that form short-chain PFCAs. Their total mass concentration in biosolids were 23,561 mg/day and they were not detected in the effluent, suggesting transformation of these precursors was an important pathway. Of note was enrichment of precursor compounds in biosolids for the non-target compounds. Of those that were analyzed, 38 were detected in greater than 10% of samples. Perfluoroethane phosphonic acid (PFPA) and polyfluoroalkyl phosphoric acid diesters (di-PAPs) were detected in more than 90% of WRRFs and thus represent two classes that warrant attention. di-PAPs have been reported as precursors that may transform into short chain PFCAs (5,9). Analysis of suspect PFAS in the influent and effluent of the 38 WRRFs showed no presence of di-PAPs in any aqueous phase samples, thus agreeing with reports suggesting that biosolids are major sink for di-PAPs.
Significance:
This study showed that PFAS ranged between 50 and 250 ng/L and that were detected at all of the 38 WRRFs sampled. Within the WRRF treatment schemes, the decrease of short chain PFCAs from influent to effluent suggests that transformation may be occurring. The result from this study provides a benchmark for comparison of PFAS occurrence in US WRRFs and a context for understanding phase partitioning and precursor transformation. Ultimately, these results from this study may be used as the basis to develop appropriate methods and to develop appropriate methods and tools to decrease PFAS release to the environment.

Quantifiable and semi-quantifiable PFAS were sampled at 38 water reuse recovery facilities (WRRFs) from 24 states in the United States (US). PFAS were detected at the influent, effluent and biosolids at every facility sampled. The sum of quantifiable PFAS concentrations were 98 Â± 28 ng/L, 80 Â± 24 ng/L, and 160,000 Â± 46,000 ng/kg dry weight (mean Â± 95% confidence interval) for the influent, effluent, and biosolids, respectively. Effluent PFAS mass loading was primarily associated with the aqueous

SpeakerHooper, Jennifer

Presentation time

15:35:00

15:50:00

Session time

15:30:00

17:00:00

TopicIntermediate Level, PFAS, Research and Innovation

Author(s)

Hooper, Jennifer

Author(s)Jennifer Hooper1; Charles Schaefer2; Dina Drennan3; Laurel Strom4; Jennifer Guelfo5; Gaya RamMohan6; Eric Dickenson7; Detlef Knappe8;

Author affiliation(s)CDM Smith, Bellevue, WA1; CDM Smith, Edison, NJ2; BEM Systems, Chatham, NJ3; CDM Smith, Bellevue, WA4; Department of Civil, Environmental & Construction Engineering, Texas Tech University, Lubbock, TX5; Hazen and Sawyer, Atlanta, GA6; Water Quality Research and Development, Southern Nevada Water Authority, Henderson, NV7; North Carolina State University, Raleigh, NC8

SourceProceedings of the Water Environment Federation

Document typeConference Paper

PublisherWater Environment Federation

Print publication date Oct 2022

DOI10.2175/193864718825158691

Volume / Issue

Content sourceWEFTEC

Word count12

Base text size -

Hooper, Jennifer

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