An Overview of Existing Municipal Landfill Leachate Treatment Techniques: Opportunities and Challenges

The chapter discusses landfill leachate, a heavily contaminated liquid waste originating from landfills, exploring its composition, environmental impact, and treatment methods. This complex mixture contains organic compounds, inorganic salts, toxic gases, halogenated hydrocarbons, and heavy metals, necessitating treatment before release into natural water bodies. The challenge lies in selecting appropriate treatment methods. For well-aged leachate, physicochemical methods like coagulation-flocculation, adsorption, membrane filtration, ozone treatment, air stripping, and advanced oxidation work best, while biological methods like membrane bioreactors, activated sludge processes, anaerobic systems, and biological contactors work best for young leachate. This book chapter explored various treatments, including bioreactors, bioremediation, phytoremediation, advanced oxidation, adsorption, coagulation-flocculation, and membrane filtration. According to existing studies, membrane bioreactors and integrated biological techniques exhibit exceptional ammonia and nitrogen removal rates above 90%. Coagulation-flocculation effectively eliminated suspended solids and turbidity. It has been found that combining methods displayed promise in removing metals at 40–100% rates. Due to its high chemical oxygen demand, ammonia concentrations, and low biodegradability, combined treatment techniques were successful for landfill leachate. Nonetheless, further research is needed to optimize methods and enhance removal efficiency. To summarize, effective treatment of hazardous landfill leachate is imperative before disposal, and the combination of biological and physicochemical approaches emerges as a promising strategy.