The factors were detected at 262 nm with the flow rate of 0.4 mL min1 and the column temperature of 30 C. For ST, the mobile phase was water with 1% glacial acetic acid and 4% methanol at a flow rate of 0.3 mL min1 and the detection wavelength was 254 nm with a column temperature of 25 C. Sterilized sludge was used to separate the adsorption part of CLX elimination and the inactivation of granules was carried out with the addition of sodium azide at 0.3% (w/v). The CLX concentrations of 20 mg L1 and 400 mg L1 were chosen for the sorption tests using acetate or ethanol as substrate respectively.