Alkaline pretreatment of sugarcane bagasse and co-digestion with cow dung for potential biogas production

Abstract

Sugarcane production in Uganda is growing at an average annual rate of 3.76% resulting in large amounts of wastes i.e., bagasse. Anaerobic digestion is a microbial degradation of organic waste in the absence of oxygen, this occurs in a sequence of biochemical reactions to produce biogas (carbon-dioxide and methane gases). The aim of the study was to evaluate potential biogas production from alkaline pre-treated bagasse and co-digested with cow dung, under mesophilic temperatures at 35±2°C with the following objectives; (i) To determine the effectiveness of alkali pretreatment on biogas production from bagasse and (ii) To estimate the effectiveness of co-digesting pre-treated sugarcane bagasse with cow dung for biogas production. The study was conducted from School of Forestry, Environmental and Geographical Sciences, laboratory at 3% TS at a working volume of 700ml in 1000ml digesters with three different substrate ratios of pre-treated sugarcane bagasse to cow-dung (SB:CD) (1:0, 2:1 and 1:1) and a control (untreated bagasse). The collected data was then analysed using Excel and Minitab software, in a number of analytical tools like averages, standard deviations, Analysis of Variance (Two-Way ANOVA) and t-test. Results showed that pre-treated bagasse produced the most biogas compared to untreated bagasse. Daily biogas collection at 1:1 ratio of SB:CD resulted into the highest cumulative biogas production of 3620 ml, followed by 2:1 ratio with 2672.5 ml biogas yield. Overall, the production of biogas from bagasse co-digested with cow dung is proven to be a good strategy to utilize solid wastes mainly bagasse.