Kinetics of microbial digestion of leachate generated from municipal solid waste

Abstract

Abstract The study addresses the challenge of leachate generation and explores various treatment processes. Specifically, it focuses on the characterization of Bhandewadi municipal solid waste leachate and evaluates its biodegradability. This evaluation involves the removal of organic and inorganic components under both anaerobic and aerobic conditions at different inoculum ratios. Additionally, the study employs mathematical kinetics models to optimize and validate the data obtained. Two sets of experiments were conducted using 25%, 50%, and 100% (raw leachate) inoculum ratios by combining leachate with inoculum seed. In the aerobic environment, a COD removal efficiency of 75% was achieved within 14 days, while in the anaerobic environment, 77% removal was observed over 18 days. To model biogas production, first-order, modified Gompertz, and logistic function models were employed and fitted to the experimental data of the 25% anaerobic set. The logistic function model proved to be the most compatible with the experimental data for this scenario. Furthermore, mathematical kinetics were also applied to validate the COD removal efficiency in the 25% inoculum ratio of the aerobic study. In this case, the first-order equation was found to be the best fit for the data. Overall, the study indicates that lower inoculum concentrations can also result in better treatment performance, particularly with a 25% inoculum ratio displaying the highest degradation efficiency under both aerobic and anaerobic conditions.