Aerobic Landfill Bioreactor Modelling and Analysis

Abstract

A tank of size 56cm 56cm 56cm is constructed using Perspex sheet supported by an aluminum frame. The reactor is equipped with 6 ports; 3 ports are used for drainage and collection of leachate, while the other 3 ports are used to recirculate the leachate collected, provide constant air flow in bioreactor and to check the temperature of the bioreactor. A 6 cm layer of aggregates is used as the bottom layer of the reactor to avoid the clogging of the drainage pipes and regulate the leachate formed in the drainage pipes. The Municipal Solid Waste used in the reactor is a mixture of organic (25kg), paper (4kg), plastic (4 kg) and metal (2 kg) waste to form a layer of 25 cm. The total weight of the msw layer used in the experiment is 35 kg having a density of 446.5 kg/m3. An air pump having a flow rate 3L/min is used to create aerobic condition inside the bioreactor. Leachate produced by the msw layer is collected and tested after every 14 days from the start of the experiment. One liter of leachate is tested for testing of pH, BOD5/COD ratio. In the present study, the effect of leachate recirculation under aerobic conditions on degradation of municipal solid waste is determined. The COD and BOD5 reduction is 86.6% and 98.1%. This shows that the leachate recirculation has increased the degradation of MSW. At the end of the experiment settlement of the waste is found to be 23.4 cm. It shows the consolidation of the msw layer and the reduction in the leachate production with the progress of the experiment. The leachate production rate is found to decrease from 5000 mL/d to 149 mL/d in 171 days. A variation in the temperature of the reactor is also observed with time.