A Review and Discussion of Wastewater Process Inhibitions Observed in the U.S. as a Result of COVID-19 Countermeasures

ABSTRACT

This paper provides a summary of case studies from water resource recovery facilities (WRRFs) in the United States that have experienced wastewater process inhibitions as a result of COVID-19 countermeasures. Anecdotal feedback from staff operating impacted WRRFs and preliminary influent toxicity screening data point to quaternary ammonium compounds (QAC) in the influent as the possible cause for the inhibition events. As such, a high-level overview of QACs, and a synopsis of their fate and potential impacts in WRRFs, are summarized in this paper. Empirical evidence from full-scale facilities is presented, demonstrating that high concentrations of disinfectants used during the pandemic caused nitrification inhibition. This paper also highlights the potential of disinfectants to inhibit enhanced biological phosphorus removal (EBPR), a treatment phenomenon not yet reported on in literature to our knowledge. Finally, the authors provide recommendations for best management operational practices to mitigate inhibitory impacts at WRRFs in the future. Copyright © 2021 Water Environment Federation