Simultaneous carbon dioxide reduction and methane generation in biogas for rural household use via anaerobic digestion of wetland grass with cow dung

Abstract

In the present study, wetland grass (common reed) and cow manure were used as substrates for biogas production during 45-days hydraulic retention reaction. The fermenter has a total volume of 200 L and a working volume of 150 L. Following biogas generation, methane enhancement processes were combined with a chemical process. The solvents including H2O, NaOH, and Ca(OH)2 were taken in two consecutive columns for 3 h, and variation of components was measured after every 15 min. The results showed 2,254 L of biogas as 343.08 ml CH4g-1VSremoved of yields, with concomitant removal of H2S by H2O, NaOH, and Ca(OH)2 absorbers. The total removal of H2S using H2O, NaOH, and Ca(OH)2 was observed to be were 55.56, 98.89, and 98.75 %, respectively. A total enhancement of methane production using NaOH and Ca(OH)2 was observed to be 88.04 and 85.9%, respectively. As a result, H2S and CO2 emissions are significantly decreased, while low-cost chemical treatments improve bio-methane generation. This study also highlights the environmental implications of co-digesting wetland grass with cow dung, and the findings indicated that the strategy is highly effective in increasing biogas production and methane contents.