Effect of Pretreatments on the Distribution and Removal of Triclosan in Waste-Activated Sludge

Triclosan (TCS) is extensively detected in wastewater and waste-activated sludge (WAS). The occurrence and fate of TCS in anaerobic digestion have been well revealed, but the change in TCS during WAS pretreatment needs to be clarified. Thermal hydrolysis pretreatment has been proven to be efficient for both WAS hydrolysis and TCS removal, with a removal efficiency of 54.0% and a retention time of 90 min at 170 degrees C. Alkaline pretreatment remarkably changed the TCS distribution between the sludge and liquid, and the solid-liquid distribution coefficient decreased by three orders of magnitude as the pH increased to 13. Neither alkaline pretreatment nor thermal-alkaline pretreatment resulted in the obvious removal of TCS. UP demonstrated limited efficiency in the hydrolysis of WAS, as well as the migration and removal of TCS. Thus, this study demonstrated that pretreatment methods and operational parameters significantly influence the migration and removal of TCS. It also provides a valuable reference for future studies on the migration and degradation behavior of TCS during anaerobic digestion and lays a foundation for the development of WAS treatment engineering capable of efficiently removing TCS.