Integrated Electro-Fenton and Membrane Bioreactor System for Matured Landfill Leachate Treatment

Abstract

Most matured landfill leachate contains organic recalcitrant molecules that cannot be easily separated by biological processes alone. Integrating an advanced oxidation process (AOP) and a biological process would be a better option for treating matured landfill leachate. Among the different AOPs, the Electro-Fenton (EF) process is the most promising technology as it is economical, effective, and environmentally friendly in processing organic waste material. Better effluent quality and a lower footprint are the significant merits of membrane bioreactor (MBR) technology, making it an attractive choice for wastewater treatment. In this study, the EF process is integrated with a MBR for treating matured landfill leachate. In EF treatment, the effect of independent variables such as pH, current density, H2O2 dosage, and reaction time on the biodegradability index [biological oxygen demand (BOD)/chemical oxygen demand (COD)] was determined using response surface methodology (RSM). Under optimum conditions (pH 2.85, current density 129.5 A/m2, H2O2 dosage 55.75%, reaction time 40 min), the biodegradability index of the matured landfill leachate increased from 0.21 to 0.45. The EF-MBR integrated system gave a total reduction in total suspended solids, BOD, COD, ammonia nitrogen, phosphate, sulfate, sulfide, and chloride of 94.2%, 90.62%, 94.55%, 84.66%, 100%, 83.19%, 85.07%, and 83.37% respectively. The economic analysis revealed that the total cost of an EF-MBR integrated treatment is $0.488/kg of COD digested and $10.68/m3 of matured landfill leachate treated. The study reveals the possibility of enhancing BOD/COD by EF and reducing the amount of pollutants considerably through an EF-MBR integrated process to guarantee environmental protection.