Fate and Removal of Triclosan in Activated Sludge Wastewater Treatment

The fate and removal of triclosan (TCS), an antimicrobial agent and emerging surface water pollutant, was studied in three full-scale activated sludge plants. Over a three-week period, daily soluble and particulate fractions of activated sludge influent, effluent, and mixed liquor solids were determined using gas chromatographic-mass spectrometry. Average influent TCS to the activated sludge process ranged from 0.021 to 0.028 mg/L (7.5 to 12 mg/capita/day). Measured TCS concentrations indicated a mean removal of 94.4% to 96.1% of influent TCS via the activated sludge treatment, and mean effluent concentrations ranging from 0.00098 to 0.0013 mg/L with a relative standard deviation of 14 to 26%. Particulate-bound TCS comprised 75 to 80% of the activated sludge influent, and 24 to 45% of the secondary effluent, therefore, the particulate fraction should be considered in future activated sludge fate and removal studies.