Anaerobic Digestion of Maize Husk in Co-Digestion with Goat and Cow Dung for Enhanced Biogas Production

Abstract

In recent investigations, Anaerobic co-digestion has been superior to traditional anaerobic digestion (AD). The advantages of employing co-substrates for improved bioenergy generation and solids reduction have drawn researchers to investigate the co-digestion technology and understand the impact of multiple substrates on digester performance. This study aimed to generate biogas by co-digestion of maize husk with cow and goat dung as substrates, isolate the bacteria involved in the process, and assess the quantity and makeup of the biogas generated by the substrates. The substrates were fed to mini-digesters fabricated in the laboratory using 1L bottles for 49 days’ retention time. It assessed the production potential of the substrates for biogas yield in mono-digestion and co-digestion. The average biogas yield (cm3) and methane content (%) in the D1, D2, D3, D4, D5, and D6 were 9135 (58%), 8660 (71%), 9820 (69%), 6545 (65%), 5915 (48%) and 1965 (21%) respectively. The highest gas yield was observed in digesters with co-digestion of the substrates (D1 and D2) than the mono-digestion of the GD and CD by 35.2% and 24.4%, respectively, with an improvement in methane content. The process was carried out in a mesophilic condition and a pH range of 6.8-8.2. The study's findings showed that the most frequently isolated and identified bacteria were Klebsiella pneumoniae and Bacillus species, indicating that these species are essential to the microbial activities involved in biogas production. The investigation additionally showed that maize husk in co-digestion with cow dung and goat dung had great potential for generating and producing large quantities of biogas within 49 days’ retention time.