Fuzzy Logic Simulation of Biodegradation of Municipal Solid Waste under Aerobic and Anaerobic Simulated Bioreactors Landfill

摘要

A fuzzy logic model was developed to simulate biodegradation of municipal solid waste (MSW) in simulated bioreactors landfill under aerobic and anaerobic conditions. The bioreactors were operated to determine the amount of leachate recirculation and municipal wastewater sludge addition required to optimize waste degradation. The leachate generated was recycled over 47 and 63 weeks, leachate samples were collected on a weekly basis and analyzed for chemical oxygen demand (COD). The temperature of the MSW in the bioreactors was measured on a daily basis. Leachate and sludge were added at the rates of 5 L/wk to 15 L/wk and 0.5 L/wk to 1.5 L/wk, respectively. Within 27 and 41 weeks for aerobic and anaerobic bioreactors, enhanced MSW degradation was observed at a leachate recirculation rate of 15 L/wk (855 mL/kg of MSW/d) and sludge addition rate of 1.5 L/wk (85 mL/kg of MSW/d). During this period, the COD concentration in the leachate dropped from 38,000 and 45,000 mg/L to approximately 1000 mg/L for aerobic and anaerobic bioreactors, respectively. Reduction in the leachate recirculation and sludge addition rate to 285 and 28 mL/kg of MWS/d respectively, increased the waste stabilization period up to 45 and 63 weeks for aerobic and anaerobic bioreactors. Within 10 and 25 weeks in aerobic and anaerobic bioreactors, temperatures reached the peak at 56 and 38 ℃ at a leachate recirculation rate of 15 L/wk (855 mL/kg of MSW/d) and sludge addition rate of 1.5 L/wk (85 mL/kg of MSW/d). Based on the two parameters, COD and temperatures, fuzzy logic approach was employed to develop a MSW biodegradation model. The results showed that fuzzy logic simulation demonstrated reasonable agreement with the experimental observations. Although there were deviations between the model simulation and measured data, the simulation results can closely predict the trend of the process. The overall evaluations of the simulation also confirmed the efficiency and reliability of the model to reproduce pertinent characteristics and important features of MSW biodegradation under leachate recirculation and sludge addition with or without air addition. In addition, the model has the ability to capture the pertinent features of the MSW biodegradation process. Accordingly the MSW biodegradation process can be accurately simulated using the fuzzy logic control approach.