*2.5. Settings of Batch and Readdition Experiments*

Two sets of experiments (batch and continuous addition) were performed under aerobic and anaerobic conditions. In the batch experiments, the aerobic experiments were performed in 125 mL serum bottles with the following contents: 45 mL of medium, 5 g of sludge, 5 mL (106 CFU/mL) of bacterial culture, and 2 mg/L SAs (SMX, SDM, SMZ), TCs (TC, OTC, CTC) or AMO, and which were incubated on a rotary shaker (120 rpm) at 30 ◦C in the dark. The anaerobic experiments were performed in 125 mL serum bottles containing 45 mL of medium, 5 g of sludge, 5 mL (106 CFU/mL) of bacterial culture, and 2 mg/L SAs (SMX, SDM, SMZ), TCs (TC, OTC, CTC) or AMO, and were conducted in an anaerobic glove box. The bottles were capped with butyl rubber stoppers and crimp seals, wrapped in aluminum foil, and then incubated without shaking at 30 ◦C. Inoculated controls containing 45 mL of medium, 5 g of sludge, and 2 mg/L SAs (SMX, SDM, SMZ), TCs (TC, OTC, CTC) or AMO, and were incubated without degrading bacteria at 30 ◦C. Sterile controls containing 45 mL of medium and 5 g of sludge were autoclaved at 121 ◦C for 30 min. SAs (SMX, SDM, SMZ), TCs (TC, OTC, CTC) or AMO were added at 2 mg/L after autoclaving. The remaining percentage of the original antibiotic content in the sludge ranged from 98.5 to 96.8%, indicating that the aerobic and anaerobic antibiotic degradation observed in all of the following experiments was due to microbial activity. Each experiment was repeated three times.

For the repeated addition experiments, sludge samples were used by adding 2 mg/L CTC, SMX and AMO three times under aerobic or anaerobic conditions. Aerobic experiments were conducted using 1000 mL bottles containing 450 mL of aerobic medium, and 50 g of sludge, with or without 50 mL (106 CFU/mL) of mixed bacterial culture. Anaerobic experiments were filled using 1000 mL bottles containing 450 mL of anaerobic medium, and 50 g of sludge, with or without 50 mL (10<sup>6</sup> CFU/mL) of mixed bacterial culture. CTC, SMX and AMO was readded into each medium when antibiotics were decreased to an undetectable level. The aerobic experiments were aerated by an air diffuser and the mixtures were stirred. The anaerobic experiments were conducted in an anaerobic glove box; capped with butyl rubber stoppers and crimp seals, wrapped in aluminum foil, and then incubated without shaking. The repeated addition experiments were performed at 30 ◦C.
