Grantee Research Project Results
2022 Progress Report: Elucidating the occurrence of known and emerging chemical contaminants in wastewater biosolids and the influence of treatment and management processes on their fate, mobility and bioavailability
EPA Grant Number: R840248Title: Elucidating the occurrence of known and emerging chemical contaminants in wastewater biosolids and the influence of treatment and management processes on their fate, mobility and bioavailability
Investigators: Hale, Robert C. , Song, Bongkeun , Guardia, Mark La , Luellen, Drew
Institution: Virginia Institute of Marine Science , Hampton Roads Sanitation District
EPA Project Officer: Packard, Benjamin H
Project Period: September 1, 2021 through July 31, 2024 (Extended to July 31, 2026)
Project Period Covered by this Report: September 1, 2021 through August 31,2022
Project Amount: $1,486,562
RFA: National Priorities: Evaluation of Pollutants in Biosolids (2020) RFA Text | Recipients Lists
Research Category: Water Quality , Water , Water Treatment
Objective:
1) Advance understanding of the composition, bioaccessibility, persistence, toxicity and mobility of chemical pollutants in wastewater sludges, biosolids and receiving soils; 2) Evaluate the influence of wastewater source and treatment choice on these; and 3) Assess sludge pollutant effects on critical wastewater treatment and soil microbial processes.
Progress Summary:
Delays in receipt and installation of major instrumentation, as well as some essential consumables, were encountered due to COVID19 pandemic-associated supply chain and vendor personnel issues. Nonetheless instruments are now installed for solid phase and enhanced solvent extraction of chemical contaminants (including chemicals of emerging concern) from aqueous and solid matrices, respectively. Also acquired and installed was a laser direct infrared (LDIR) chemical imaging system permitting the identification and quantification of microplastics (i.e., polymer-based particles from 1 um to 5000 µm in size). A chemical reactor capable of maintaining temperatures and pressures spanning those employed in the thermal hydrolysis process (THP; used to treat wastewater sludge to destroy pathogens, degrade natural polymeric substances and facilitate sludge dewatering) has been installed at HRSD.
A preliminary investigation of the impact of microplastics on ammonia oxidation (critical to wastewater treatment processes) was conducted using the bacterium, Nitrosospira sp. AV. Four different polymer types (PVC, PE, PUF, and PLA) were tested in aqueous incubation experiments. The presence of PVC and PUF reduced ammonia oxidation by Nitrosospira sp. AV. Parallel experiments were conducted with UV-weathered microplastics of corresponding polymer types. Inhibition of nitrification was not observed with the UV-weathered PVC. This indicates that UV weathering of some polymer types may alter their ability to affect important nutrient cycling processes.
Future Activities:
In the coming year we will focus on establishing and validating mass spectrometric methods for detecting targeted and non-targeted chemical contaminants (including contaminants of emerging concern (CECs)) in wastewater/sludge matrices. We will also validate methods for the determination of microplastics using the newly acquired LDIR. The influence of elevated temperature, pressure and dissolved organic carbon (encompassing conditions encountered during THP) on the physical conformation of microplastics and chemical additive mobilities will be investigated. Microplastic shape and size may be altered by exposure to elevated temperatures, as a function of polymer melting point. The possibility of using the more automated enhanced solvent extraction instrument versus the reactor to assess this will be investigated. Instrumentation to permit detection of microbially-derived endotoxins will be acquired and methodologies validated.
To assess the impact of CECs/microplastics, additional nitrifying microbes will be investigated.
Journal Articles:
No journal articles submitted with this report: View all 10 publications for this projectSupplemental Keywords:
wastewater residuals, environmental chemistry, toxicsProgress and Final Reports:
Original AbstractThe perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.