Effect of Pre Digestion Time on Efficiency of Biogas Production

Abstract

Aims: Waste-to-Energy transformation has been identified as a veritable option in the integrated waste management processing of Municipal Solid Waste. The use of biogas technology to produce energy and organic fertilizer from organic waste initially from livestock farm waste and agro-industrial waste is a potential way of MSW management. The aim of this study was to determine the optimum time required for pre digestion of solid wastes before biogas production process begun. Study Design:  the study designed to operate on two batches and two phase experiments; the first batch was materials composted in four weeks and the second batch was in two weeks time in order to see which time will be effective on biogasification. Place and Duration of Study: The study was done at the research center of the Environmental Engineering school, Ardhi university, between February and July 2013. Methodology: The method used was the volume displacement method where by the first phase experiment set up was aerobic composting that includes five reactors of printer paper to sugarcane waste in various proportions which were R1 (100:0), R2 (75:25), R3 (50:50), R4 (25:75) and R5 (0:100). During composting process temperature, moisture content, and pH, were monitored and process run for the periods of 30 days.The second phase experiment set up was bio gasification whereby the reactor allowed to ferment anaerobic for a period of 60 days. Each reactor contains composted printer paper with sugar cane waste and cow dung in the following ratios;  substrate to seed for each composted reactor in every batch 100:0, 75:25, 50:50, 25:75 and 0:100. Initial temperature was measurements were determined since have effects on biogas production. Results: The findings from this study show that, there is a significant biogas production from Co-digestion of pre-composted printed paper and sugar cane waste. Only R4 (25:75) and R5 (0:100) are the optimum ratios of printer paper to sugarcane waste during composting, Physical and chemical characteristics of both substrates (composted printer paper and sugar cane waste) and seed (cow dung) used for biogas production was in the range to support biogas production, Quantification of biogas produced was high from R4, R5, R3, R2 to R1. Conclusion: materials pre-composted for four weeks yield more gas compared to two weeks composted materials and Sugarcane wastes as the stimulant materials increase biogas production since as the percent of sugar cane wastes increase the biogas yield also was increased.So the increase of pre digestion time seems to increase biogas yield in biogasification process.