Combined microbial desalination and chemical-production cell with Fenton process for treatment of electroplating wastewater nanofiltration concentrate

Abstract

With high concentrations of salinity, heavy metals, and refractory organics, the nanofiltration (NF) concentrate in electroplating wastewater is difficult to be treated using the traditional methods. The aim of this study was to investigate the feasibility to treat the NF concentrate using the microbial electrolysis desalination and chemical production cell (MEDCC) combined with the Fenton process. Results showed that heavy metals of nickel and zinc were efficiently removed using the proposed method. The maximum current density reached 9.4 A/m2 in the MEDCC fed with the pretreated NF concentrate. Within 20 h, 94%, 82%, and 91% of nickel, zinc, and calcium were removed in the desalination chamber of MEDCC. The dilute acid with pH = 0.9 and alkali with pH = 12.9 were recovered in the MEDCC. The Fenton oxidation process with and without the MEDCC removed COD 79% and 30%, respectively. In the MEDCC and Fenton combined system, refractory organics were transformed to linear alkanes and efficiently degraded. With high removal of COD and heavy metals, acid and alkali recovery, and low energy consumption, our combined MEDCC and Fenton process should provide a promising method to efficiently treat the NF concentrate in electroplating wastewater.