Treatment of reverse osmosis concentrate using microbial electrolysis desalination and chemical production cell

Abstract

Containing high salinity and biotoxic organic compounds, reverse osmosis (RO) concentrate from municipal wastewater treatment plants has high environmental risks. The aim of this study was to investigate the feasibility of RO concentrate treatment using the microbial electrolysis desalination and chemical production cell (MEDCC). RO concentrate was put into the desalination chamber. Both acid production and cathode chambers contained with 1g/L NaCl. Within 18h operation, the maximum desalination rate of 86±7% and no significant COD removal in the RO concentrate were achieved in the MEDCC, although the humic-like and fulvic acid-like organic compoundscould transfer from the desalination chamber into the acid-production chamber. The minimum and maximum pH in the acid-production and cathode chambers reached 1.08±0.06 and 12.2±0.10, respectively. The average total energy consumption was 6.51±0.17–9.81±0.23kWh/m3, among which 37%–61% was provided by the bioenergy from substrate utilization. The acid and alkali recovery, COD rejection in the treated RO concentrate and low electricity consumption in the MEDCC indicate that MEDCC may be a novel method for RO concentrate treatment in practical applications.