Experimental and Mathematical Modelling for Methane Biogas Production from Mixing of Real Municipal Solid Waste and Sewage Sludge

Biogas (methane) production from batch anaerobic digesters containing varying ratio of organic fraction municipal solid waste and sewage sludge, pH, temperature and total solid are studied for a period of 30 days. It was observed that biogas production was optimized when waste and inoculum were mixed in a ratio of 5:1.At temperature, total solid and pH of 35oC, 10 % and of 7.5 respectively. The maximum accumulative methane production is 450 mL/gm V.S. First order model was developed to assess the kinetics of the biodegradation process used to adequately describe the cumulative methane production from these digesters. It was observed that the rates of substrate biodegradability and removal of the biodegradable fractions of the substrate could be obtained by plotting 1/t (ln(dyt/dt)) against the inverse of time of digestion. This modified first order model also showed that the digester containing waste and inoculum in the ratio of 5:1 had the highest short term anaerobic biodegradability index (STABI) of 2.0424 and R2= 0.9385 In addition, The modified Gompertz equation was used to adequately describe the cumulative biogas production from these digesters. The kinetic parameters viz., biogas yield potential (B), the maximum biogas production rate (Rb) and the duration of lag phase (λ) were estimated at optimum condition obtained. The highest biogas yield of 450 mL/gm V.S and kinetic parameters B, Rb and λ were 455.6523mL/gm V.S, 35.161mL/gm V.S d-1 , 5.0542 d respectively where R2 0.9997. To optimizing the production of methane the multiple correlations was used with a correlation coefficient of 92.687%.