Biogas Production from the Paddy Straw Pretreated with Sodium Hydroxide and Co-Digestion with Cow Manure

Abstract

Paddy straw waste (PS) is an organic waste that is disposed in open land after preparation of rice harvest that is generated in equal or greater quantities than the rice itself. Generally, it is disposed in open land, which increases anthropogenic gases. Converting it into useful energy or value-added products may reduce disposal problems and anthropogenic activity. In this study, PS with different treatments of sodium hydroxide (NaOH) at 2, 4, 6 , 8 and 10% was co-digested with cow dung (CD) for obtaining biogas by anaerobic digestion. For this purpose, PS was mixed with CD at different proportions, namely 50:50, 40:60, 30:70, 20:80, and 0:100 percentages on a mass basis, the samples were used in five different anaerobic digesters. The samples were kept in different anaerobic digesters for the study. The effect of important input parameters like pH and Carbon to Nitrogen (C/N) ratio on the biogas production was studied. Maximum biogas production was obtained from the co-digestion of the substrate containing 30% ps and 70% Cd for a digestion time of 20 days, and d3 shows a max pH value of 7.16. Further, the biogas collected from the digesters was characterized to ensure suitability for use as a renewable fuel. Furthermore, the digested slurry was also analyzed for its use in agriculture. The results are presented in this paper.