Optimization of a bioelectrochemical system for 2,4-dichloronitrobenzene transformation using response surface methodology

In the present study, a bioelectrochemical system (BES) was developed for 2,4-dichloronitrobenzene (DClNB) transformation. Response surface methodology (RSM) was applied to optimize the operational conditions, including the V/S ratio (volume of the BES/size of the electrode ratio), interval (D) (distance between the anode and cathode) and position (P) (proportion of the electrodes immerged in the sludge). The optimum conditions for the V/S ratio, interval and position were 40, 2.31 cm and 0.42. The pollutant removal rate and increase in Cl(−) were 1.819 ± 0.037 mg L(−1) h(−1) and 11.894 ± 0.180 mg L(−1), which were close to the predicted values (1.908 mg L(−1) h(−1) and 12.485 mg L(−1)). A continuous experiment indicated that the pollutant removal efficiency in the BES with 50% of the electrodes immerged in the sludge was 34.6% and 22.6% higher than that in the ones with 0 and 100% of the electrodes immerged in the sludge.