Performance Evaluation of Solid State Digester for Biogas Production using Biologically Pretreated Straw Urmila Gupta Phutela, Anand Gautam and Karamjeet Kaur School of Energy Studies for Agriculture, College of Agricultural Engineering and Technology, Punjab Agricultural University Ludhiana – 141 004, Punjab, India Email: phutelau@gmail.com, aanand.gautam@gmail.com, karamjeet7@gmail.com Paper No. 170 Received: June 17, 2013 Accepted: August 21, 2013 Published: November 29, 2013 Abstract The present paper reports biogas production from biologically pretreated paddy straw in a solid state digester made of HDPE plastic (124litre capacity). The trial was conducted with a mixture of 10 kg pretreated paddy straw, 20 kg cattle dung slurry, 20 kg cattle dung and 20 litre water. The chemical and proximate analysis of the feed was done and biogas production profile was studied over a period of one month. Parallel trial was also conducted with untreated paddy straw. The result indicated that 253.89 litre biogas/kg pretreated paddy straw was produced, which is 39.3% higher than the untreated paddy straw. Highlights • Fabricated digester worked well for biogas generation from untreatedas well as pretreated paddy straw. • 39.3% enhancement in biogas production was observed in case of pretreated straw. Keywords: Solid State Digester, Biogas, Paddy Straw, Pleurotus florida ©2013 New Delhi Publishers. All rights reserved International Journal of Agriculture, Environment & Biotechnology Citation: IJAEB: 6(4): 691-694 December 2013 DOI Number 10.5958/j.2230-732X.6.4.050 One of the most abundant lignocellulosic wastes on earth is paddy straw. More than 200 million tons of paddy straw is estimated to be produced annually. About 70% of paddy straw is burnt in the fields which causes lung and respiratory diseases and adversely affect public health (Wang and Christopher, 2003). Furthermore, repeated burning of paddy straw also results in soil erosion. Thus, an alternative to utilize paddy straw is to use it as a feedstock for biogas production. Though, biogas can be produced from paddy straw by anaerobic fermentation using cattle dung slurry as a source of inoculum. But, very few attempts have been made to investigate the potential of paddy straw as sole feedstock to produce biogas (Borjesson and Mattiasson, 2007). The barrier to which is the structure of paddy straw which has evolved to resist degradation due to crosslinking between the polysaccharides (cellulose and hemicellulose) and the lignin via ester/ether linkages (Yan and Shuya 2006). Efforts are being made worldwide to increase paddy straw digestibility by chemical, physical and biological means (Mosier et al., 2005; Taherzadeh and Karimi, 2008; Hu et al., 2008; Hendriks and Zeeman, 2009; Alvira et al., 2010). Biogas is composed of CH 4 (55-65%), CO 2 (30-45%), H 2 (1-5%), N 2 (0.5-2.0%), H 2 S (0.1-0.5%), CO (0-0.3%) and traces of water vapors (Pauss et al., 1987). The key to Agricultural Engineering