Simultaneous Desalination and Removal of Recalcitrant Organics from Reverse Osmosis Leachate Concentrate by Electrochemical Oxidation

Reverse osmosis (RO) concentrate produced in the municipal solid waste (MSW) leachate treatment process is extremely hard to be treated because of its high color, high salt content, and high concentration of recalcitrant organic compounds. A new multichannel flow reactor with electrode gaps of 5 mm was designed to desalinate and remove organics simultaneously from the RO leachate concentrate (ROLC) by electrochemical oxidation process using the RuO2/IrO2-coated titanium plate (RuO2/IrO2-Ti) as the anodes. The effects of the process parameters of current density (I-A), superficial circulating velocity (U-L), etc. on the removal efficiency (RE) of the chemical oxygen demand (COD) and average energy consumption ((EC) over bar) were investigated. The results illustrated that after 3 h of treatment, the RE of COD, Cl-, and color could reach as high as 96.5, 96.7, and 99.6%, respectively. Besides, the (EC) over bar of the electrochemical oxidation treatment process is as low as 40.98 kWh/(kg COD), and a new mechanism of the simultaneous removal of COD and desalination has been proposed. This work provides an alternative technology for the treatment of MSW leachate RO concentrate.