1. State Key Laboratory of Urban Water Resources and Environment, School of Municipal and Environmental Engineering, Harbin Institute of Technology, Harbin 150090, China;
2. Beijing Origin Water Technology Co.Ltd, Beijing 100090, China
To evaluate the removal of the chemical oxygen demand (COD) and nitrogen (TN) within the landfill leachate effluent, the combined electrochemical integrated process of electro-oxidation/electro-coagulation was constructed. In this system, the dimensional stable electrode was used as anode and graphite felt as cathode, moreover, the iron net was applied as bipolar electrode. The effect of plate distance, circulation velocity and chloride ion (Cl-) concentration on COD and TN reduction was investigated using the single factor experiment and response surface methodology (RSM). Via the analysis of variance, a quadratic response surface model with significant level was obtained. Experimental results demonstrated that the optimum conditions for COD removal were 3.8cm plate distance, 1mL/min velocity and 5556mg/L Cl- concentration, respectively, leading to a COD removal efficiency of 84.6% (forecast COD reduction was 85.4%). The optimum conditions for TN removal were 5.7cm plate distance, 1mL/min circulation velocity and 5437mg/L Cl-concentration, with a TN removal rate of 86.4% (VS forecast value of 93.0%). Meanwhile, the phosphorus and color were also significantly removed by the combination process. In overall, the simultaneous removal of predominant contaminants within landfill leachate achieved during the electro-oxidation/electro-coagulation combination process was meaningful for pollutants control.
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