Assessing the Feasibility of Microbially Managed Biological Filtration in U.S. Drinking Water Systems for Removal of Contaminants of Emerging Concern

The future of water security in the U.S. is clouded by the progression of anthropogenic climate change and the increasing number of households unable to afford access to safe drinking water, while advances in detection and potential health risks of trace organic contaminants are constantly moving the water treatment finish line. There is a need for sustainable, economically feasible technology to provide the means to meet increasingly stringent water quality regulations while also ensuring current standards are met for all communities. Biologically active filtration, combined with an operational approach designed to optimize contaminant removal by the biofilm, may enable water treatment facilities to meet current and future needs by utilizing challenging water sources.This research expands the current understanding of biological filtration for U.S. drinking water treatment and its potential role in addressing contaminants of emerging concern through an analysis of several datasets to address whether biofiltration is a feasible treatment option for 1,4-dioxane removal. Unregulated Contaminant Monitoring Rule (UCMR) data were found to represent only 8.9% of public water systems (PWSs) in the U.S., but these PWSs provide the drinking water for 83.1% of the population. Common practices in biological filtration include ozone combined with chlorine disinfection, dual media, and mostly surface waters as the primary water source. Most systems surveyed backwash biofilters with unchlorinated water and report total organic carbon (TOC) removal and taste and odor as biofiltration targets. For 1,4-dioxane occurrence, 22.2% of PWSs had detectable levels, averaging 0.151 µg/L. Of these PWSs, most were in U.S. Environmental Protection Agency (EPA) regions that report the most biofiltration and granular activated carbon (GAC) filtration use in treatment process schemes, representing an opportunity to upgrade to or introduce biological filtration in these PWSs