Biogas production rate with methane content from market garbage in dry batch biogas system

Abstract

Biogas technology can play a vital role in solving energy problems while utilizing the degradable solid organic waste as a raw material for the biogas generation. New researches on biogas technology are required for the better adoption within community. The present research was conducted for about six month period to find the possible avenues to evaluate the biogas production from market garbage. The objectives of the study were to (1) analyze the chemical and physical composition of market garbage, (2) to assess the biogas production from market garbage and (3) to analyze the methane ontent of biogas. Sri Lankan dry batch digester was used in the study with a volume of ~5m3 and the total weight of market garbage filled in to the digester was ~3240kg (fresh weight). Cow dung (~80kg) was added as inoculums. Daily biogas production and its methane content were monitored during the study period. Temperatures at different depth of the digester were also recorded. Average total solids Qf market garbage fed into the digester were -9.27 %. Results revealed that 43.38% (±2.89) and 11.50% (±2.22) of market garbage were cabbage and brinjal, respectively. The bulk density of market garbage was ~0.91g/cm3. Carbon, Nitrogen, ash, volatile solids and C: N ratio of market garbage was 39.16% (±2.53), 1.57% (±0.05), 1.91%, 12.20%, 87.80% and -20.47, respectively. The total biogas production was 89.13m3 during the 127 days. The total biogas production per 1kg of total solids was -283 L. Maximum biogas production (1.47 m3/day) and methane content (67%) of biogas were observed at 86 and 84 days of initial charge, respectively. The energy content of produced biogas was -1916 MJ. Based on the study, it can be concluded that market garbage could be easily utilized as a raw material for biogas production having higher methane content in the dry batch digester.