The advanced treatment of mature landfill leachate by iron-carbon micro-electrolysis combined with persulfate activated (ICME-PS) process

High concentration refractory organic matters, particular humic substances, often account for the majority of organic pollutants in mature landfill leachate, which cannot be effectively decomposed by biological processes. The iron-carbon micro-electrolysis combined with persulfate activated (ICME-PS) process was developed for the advanced treatment of biologically treated mature landfill leachate in this study. By employing the single factor experiment and Response Surface Methodology, the maximum COD removal rate reached 83.45% under the optimal conditions: persulfate dosage of 35.60 g/L, Fe-C dosage of 210.69 g/L, aeration rate of 0.44 L/min and initial pH of 6.70. Among them, persulfate dosage and initial pH had more significant effects on the COD removal of the ICME-PS process. Furthermore, the application of ICME-PS process in continuous flow mode indicated that the COD removal rate could reach 79.97 %, which demonstrated the feasibility of ICME-PS process in practical application. Through the ICME-PS process, conjugated polymers, aromatic compounds and polycyclic aromatic hydrocarbons in mature landfill leachate were broken down into various small molecular organic matters. The humic acid-like substances were destroyed and the humification degree was reduced. Taken together, the ICME-PS process provides an effective method for landfill leachate advanced treatment.