ANAEROBIC CO-DIGESTION OF KITCHEN WASTE AND SEWAGE SLUDGE FOR PRODUCING BIOGAS

In this paper, an attempt has been made to present the result of some experiments conducted on anaerobic digesters to make comparative study of the biogas generation capacity of the mixture of organic fractions of municipal solid waste from kitchen waste and sewage sludge in different composition. Batch digestion of samples with various percentage of kitchen waste and sewage sludge was carried out under controlled temperature 35C and pH 7 conditions for 15 days for each experiment. In all experiments the content of total solid and volatile solid, pH, kjeldahl nitrogen, chemical oxygen demand, biogas productivity and the content of biogas was measured. The results obtained showed that biogas productivity varied between 4.6 and 59.7 ml depending on the composition of each component in the sample added to the digesters. The bioprocess efficiency was observed to be 7.5% - 70.5% for total solid, 51.2% - 81.0% for volatile solid and 8.3% - 43.8% for COD. The overall effluent chemical oxygen demand concentration indicates that it should be treated before using for other applications. From the study results, it is evident that the second bioreactor with 75% of kitchen waste and 25% of sewage sludge produced the maximum quantity of methane gas as compared to other bioreactors.