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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 RuO 2 /IrO 2 -coated titanium plate (RuO 2 /IrO 2 -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) 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 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.

Electrochemical oxidation (EO) is often used in the advanced treatment of refractory wastewater. However, in a conventional EO process of direct-current (DC) power supply, oxide layers often form on the anodes, which not only hinder the oxidation reaction on them but also cause higher energy consumption. In this paper, a biologically treated leachate (BTL) of municipal solid waste (MSW) was comparably treated by EO with DC (DC–EO), monopulse (MP–EO), and double pulse (DP–EO) power source models in a home-made multi-channel flow reactor. The effects of process parameters of current density (I A), superficial liquid velocity (U L), pulse frequency (f P), duty ratio (R D), and so forth on the removal efficiency of chemical oxygen demand (COD) (RECOD), total organic carbon (TOC) (RETOC), and total nitrogen (TN) (RETN) were investigated simultaneously. Average energy consumption ( ) and organic composition of the treated effluent of DC–EO and MP–EO were also compared comprehensively, and a new mechanism of MP–EO has been proposed accordingly. Under optimal conditions, 2 L of BTL was treated by MP–EO for 180 min, and the RECOD, RETOC, and RETN could reach as high as 80, 30, and 80%, respectively. Compared with DC–EO, the of MP–EO is reduced by 69.27%. Besides, the kinds of organic matter in the treated effluent of MP–EO are reduced from 53 in the BTL to 11, which is much less than in the DC–EO process of 29 kinds. Therefore, the MP–EO process exhibits excellent removal performance of organics and TN and economic prospects in the treatment of refractory organic wastewater.

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