Review on landfill leachate treatments

Thesis Abstract

Landfill leachate is a complex wastewater generated from the decomposition of solid waste in landfills. It contains a wide range of contaminants, including heavy metals, organic compounds, nutrients, and pathogens, making it a significant environmental concern. Various treatment methods have been developed to mitigate the impact of landfill leachate on the environment. This review paper provides an overview of the different treatment technologies employed for landfill leachate remediation. Conventional treatment methods such as physical-chemical processes, biological processes, and advanced oxidation processes are discussed in detail. Physical-chemical processes, including coagulation-flocculation, adsorption, and membrane filtration, have been widely used for leachate treatment due to their effectiveness in removing contaminants. Biological treatment methods, such as activated sludge, moving bed biofilm reactors, and sequencing batch reactors, offer cost-effective and sustainable options for leachate treatment by utilizing microorganisms to degrade organic pollutants. Advanced oxidation processes, such as ozonation, photocatalysis, and Fenton oxidation, have shown promising results in treating refractory compounds in leachate. These processes generate highly reactive hydroxyl radicals to degrade recalcitrant organic pollutants effectively. In addition to these conventional methods, emerging technologies like membrane bioreactors, constructed wetlands, and electrochemical oxidation are gaining attention for their efficiency in treating landfill leachate. The selection of an appropriate treatment method for landfill leachate depends on various factors, including the characteristics of the leachate, treatment objectives, available resources, and environmental regulations. Integration of multiple treatment processes in a treatment train has been proposed to achieve higher removal efficiencies and ensure compliance with discharge standards. Moreover, the concept of zero liquid discharge has been explored to minimize the volume of leachate requiring treatment and disposal. Overall, this review highlights the importance of effective landfill leachate treatment to protect human health and the environment. Continuous research and development efforts are needed to improve existing treatment technologies, develop innovative solutions, and optimize treatment processes for sustainable management of landfill leachate. Collaboration between researchers, practitioners, and policymakers is essential to address the challenges associated with landfill leachate treatment and promote environmental sustainability.