| Abstract: | Landfill leachate treated with combined process of "pretreatment +biological treatment +advanced treatment(NF)" to produce nanofiltration concentrate, which bio-chemical ratio(B/C) is less than 0.1 and CODcr concentration is 2 000-2 500 mg/L, high salt content. Which cannot be discharged under existing environmental standards. According to analysis based on electrochemical advanced oxidation mechanism, a two-step electrochemical technique was recommended. In the first step, a pulse electrochemical technique was adopted. With Fe as consumption electrode and current density of 10 mA/cm2, the pollutants were removed by means of Fenton reaction, electroflotation and electrocoagulation. In the second step, a double function electrode was used to perform electrocatalytic oxidation by means of titanium metallic oxidates. In the condition that current density being 12.5 mA/cm2, the pollutants were further removed by oxidation and electrolytic deposition. Result shows that the removing rate of CODcr, NH3-N and Cl- were 70%-85%, 90% and 25%, respectively; average value of B/C ratio increased from 0.09 to 0.38 and conductivity reduced by 10%. |
