A short review on landfill leachate treatment technologies

Abstract

The solid waste disposal problem is a well-known global environmental issue, wherein landfilling and open dumping are the most widely followed practices. The production of toxic liquid, leachate, is a significant issue with landfilling practices. This leachate needs to be treated carefully before its disposal in the environment. Landfill leachate is characterized by very high chemical oxygen demand (COD) and biochemical oxygen demand (BOD) consisting of unappealing constituents like toxic organic and inorganic pollutants. In general, leachate parameters such as landfill age, COD/BOD ratio, and COD are the decisive factors in the selection of appropriate treatment methods. The various adopted technologies for leachate treatment are assessed and summarized under heads like biological, physicochemical, and hybrid methods. The purpose of this research is to look at the technological improvements used for landfill leachate treatment, taking into account the lessons learnt over time and the solutions that have been implemented. It was observed that, when the treatment techniques are employed in standalone mode, they are unable to meet the acceptable water quality criteria, nevertheless when the treatment techniques are used in combination, then it meets the stringent criteria for disposal. The integrated biological and physicochemical treatment methods are viewed as critical for adhering to sustainable release limits and ensuring environmental protection by achieving satisfactory COD, BOD, and ammonia nitrogen removal efficiencies. The evaluation includes state-of-the-art research outputs as well as potential combined applications of various treatment strategies covered in previous works.