Effects of operating parameters on electrochemical treatment of swine wastewater

Abstract

This study focuses on the electrochemical treatment of swine wastewater under different parameters (anode material, cathode distance, cathode area, and wastewater volume). The results showed that for a total of 16 tests, the pseudo-first-order COD and NH3-N removal rate constants ranged from 9.00x10-5-5.98x10-4 and 5.66x10-5-1.45x10-3 1/s, respectively, with removal efficiencies of 79%-100% and 72%-100%, respectively. The range of specific energy consumption (ESP) was 32-358 kWh/kg-COD. The performance of a lab-prepared boron-doped diamond (BDD) anode was comparable to that of a commercial anode for the electrochemical removal of COD and NH3-N in swine wastewater. Among tested anode materials, IrO2/Ta2O5 exhibited the lowest performance in terms of COD and NH3-N removal, and BDD showed better COD degradation performance than PbO2 although an opposite trend was observed for NH3-N removal. The COD and NH3-N removal efficiencies increased as the electrode distance increased. Increasing the cathode area also increased the removal efficiency of pollutants and was beneficial for controlling the final pH. Of all the tests, the lowest ESP (32 kWh/kg-COD) was obtained by increasing the wastewater volume and lowering the current density, which can be considered for energy or cost savings related to operation.