Kinetics for degradation of bisphenol A during aerobic composting of sewage sludge and sawdust.

To investigate the kinetics of the degradation of bisphenol A (BPA) by aerobic composting of sewage sludge (SS) and the effects of the major controlling factors, six pilot-scale (5 L) and 10 bench-scale (0.5 L) trials were conducted using sawdust as the amendment. For BPA with initial concentrations of 0.349-0.551 mg kg^-1 in pilot-scale trials, half the BPA was removed within the first 2.5-7.5 d of the 14-d composting process. Fitting the pilot-scale BPA reduction data to first-order kinetic models indicated that degradation rate constants and half-lives for BPA ranged from 0.095 to 0.175 d^-1 and from 4.0 to 7.3 d, respectively. Kinetic parameters were obtained from bench-scale trials under various controlling factors such as initial concentration of BPA, aeration, moisture content and temperature. The results showed that thermophilic aerobic biodegradation was the main mechanism for BPA removal during the aerobic stabilization phase of SS composting. The optimum conditions for BPA degradation were 0.3-30 mg kg^-1 initial concentration, 0.050-0.100 L min^-1 kg^-1 aeration rate, 60%-70% moisture content and 60°C-70°C temperature. Our findings could be used to further the enhancement of BPA biodegradation in SS or other solid wastes. [ABSTRACT FROM AUTHOR]