Biotransformation of trace organic compounds by activated sludge from a biological nutrient removal treatment system

The removal of trace organic compounds (TOrCs) and their biotransformation rates, k(b) (L g(SS)(1) h(-1)) was investigated across different redox zones in a biological nutrient removal (BNR) system using an OECD batch test. Biodegradation kinetics of fourteen TOrCs with initial concentration of 1-36 mu g L-1 in activated sludge were monitored over the course of 24 h. Degradation kinetic behavior for the TOrCs fell into four groupings: Group 1 (atenolol) was biotransformed (0.018-0.22 L g(SS)(1) h(-1)) under anaerobic, anoxic, and aerobic conditions. Group 2 (meprobamate and trimethoprim) biotransformed (0.010.21 L g(SS)(1) h(-1)) under anoxic and aerobic conditions, Group 3 (DEET, gemfibrozil and triclosan) only biotransformed (0.034-0.26 L g(SS)(1) h(-1)) under aerobic conditions, and Group 4 (carbamazepine, primidone, sucralose and TCEP) exhibited little to no biotransformation (<0.001 L g(SS)(1) h(-1)) under any redox conditions. BNR treatment did not provide a barrier against Group 4 compounds. (C) 2016 Elsevier Ltd. All rights reserved.