Employing TiO₂ photocatalysis to deal with landfill leachate: Current status and development

Sanitary landfilling is a low cost and well established waste disposal technique applied worldwide. However, its generation of heavily polluted leachate is considered as a major concern. Municipal solid waste (MSW) landfill leachate contains a wide variety of recalcitrant compounds that make it quite difficult to treat using conventional ways of treatment due to its high chemical stability and/or low biodegradability. In the last couple of years, photo-assisted titanium dioxide (TiO₂) oxidation has shown a great potential to treat landfill leachate. This article presents a systematic literature review of heterogeneous TiO₂ photocatalysis dealing with pre and post treatment of MSW landfill leachate. Recent advancement of TiO₂ photocatalysis in treating recalcitrant organic and inorganic pollutants found in landfill leachate are discussed; whereas, evaluation of the mechanism of the process, configurations of photoreactor system and influence of certain operating factors on system efficiency are also part of the review. Finally, comparative evaluation of this technique with other advanced oxidation processes (AOPs) and advantages and disadvantages of the technology are highlighted coupled with future research perspective.