Optimization of an A2/O process for tetracycline removal via response surface methodology coupled with a Box-Behnken design

Response surface methodology (RSM) was used to optimize the operating conditions of an anaerobic-anoxic-oxic (A(2)/O) process by maximizing the removal efficiency of tetracycline (TC). Solid retention time (SRT), hydraulic retention time (HRT) and initial TC concentration (C-TC,C- in) were selected as independent variables for incorporation in the Box-Behnken design. The results showed SRT and C-TC,C- in were more significant parameters than HRT for the removal efficiency of TC. TC could be completely removed under the optimal conditions of an SRT of 15.5days, an HRT of 9.9h and a C-TC,C- in of 283.3 mu g L-1. TC removal efficiencies of 99% and 96% were attained for synthetic and real wastewater, respectively, under the optimal conditions. This indicated the constructed model was validated and reliable for optimizing the A(2)/O process for TC removal.