Comparative study of commercial gas with biogas produced from co-digestion of corn cob, rice chaff, goat and dog dungs

Investigations were conducted to compare gas produced from co-digestion of corncob, rice chaff, goat dung and dog dung with commercial gas. The study was carried out anaerobically at a temperature of 29.5 to 33°C (mesophilic condition) in a mini laboratory digester (bioreactor) fabricated using guage 16 metal sheets with 80-L capacity for a 90-day retention time. The shredded corn cob and rice chaff were mixed with water at ratio 4:1 (waste to water) and 3:1 (waste to water) respectively and mixed with goat and dog dungs at ratio 2:1 (waste to water). The control sample collected from a domestic cooking gas cylinder contained 56.12% CH2, 0.14% NH3, 0.22% CO, 0.23% H2S and 43.20% CO2. The result obtained for the biogas analysis shows that Sample E (75:25) contains 63.54% CH4, 0.93% NH3, 0.84% CO, 0.54% H2S, 34.12% CO2. The value recorded for sample E represented the highest value obtained among the samples. Also the gas composition shows a good substitute for commercial gas. Key words: Corn cob, rice chaff, goat dung, dog dung, biogas, commercial gas, bioreactor and digestates.