Fate of antimicrobial compounds during wastewater treatment

ENVR 185

Jochen Heidler and Rolf U. Halden. Environmental Health Sciences, Johns Hopkins Bloomberg School of Public Health, 615 N. Wolfe St., Room # W6704, Baltimore, MD 21205
Triclosan and related persistent disinfectants (PDs) are common additives of antimicrobial personal care products. Following down-the-drain disposal, the ultimate fate of these PDs in municipal wastewater treatment plants (WWTPs) is largely unknown. We conducted a mass balance on selected PDs by analyzing samples of influent, effluent and biosolids from a 180 MGD plant in Baltimore. Partitioning, biotransformation and removal rates of selected PDs were estimated by analyzing grab and composite samples using liquid chromatography electrospray ionization mass spectrometry (LC/ESI/MS). Removal rates for PDs were calculated by dividing 24-hour effluent concentrations by the corresponding influent concentrations. Removal efficiencies for PDs typically were greater than 90%. However, triclosan and other polychlorinated PDs resisted biodegradation and accumulated in biosolids at mg/kg levels. Study results suggest that the land application of municipal biosolids represents a potential pathway for reentry of persistent PDs into the environment.