IMPACT OF LEACHATE RECIRCULATION ON THE PRODUCTION AND QUALITY OF BIOGAS IN LANDFILLS: SYSTEMATIC REVIEW

Abstract

Biogas and leachate generated from the decomposition of munipal solid waste (MSW) in landfills, when not collected and treated, might cause environmental impacts. Leachate recirculation (LR) is a technique that has been used, among others factors, as a way of reducing the costs associated with the transport and treatment of leachate, as well as contributing to a faster stabilization of the organic fraction of MSW, which could impact an increase in biogas production in a shorter period of time. This work aimed to evaluate the influence of LR on the production and quality of biogas generated in landfills through a systematic review of research carried out in the last decade, thus to support an updated synthesis of the main results obtained in laboratory and large scale. The results found showed that the accumulation of toxic compounds is one of the main problems observed with the practice of LR. The use of additives, the control of the rate and frequency of recirculation and the supplementation of heat to the recirculated leachate were some of the techniques observed that have been investigated as a way of improving the influence of recirculation in the process of biodegradation of waste and increase the production of biogas. The results found showed that RL impacted in different ways the production and quality of the biogas generated through the decomposition of waste, proving to be effective in some studies to increase the production and quality of biogas, as well as ineffective in other studies.