Abstract
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•Water hyacinth (WH) co-digested with cattle dung (CD) at various mixing ratios.•Co-digestion is a key approach for enhanced biogas and methane (CH4) production.•Co-digestion increased biogas and CH4 production by 111.3 and 173.6%, respectively.•Co-digestion improved bacterial population as given by VIT® gene probe technology.•WH/CD gate fee had a noticeable impact on co-digestion economic feasibility.
This study might be the first to explore the techno-economic implications of anaerobic co-digestion of water hyacinth (WH) and cattle dung (CD) to optimize their mixing ratios for enhancing methane (CH4) production. At a mixing ratio of 1:1, the maximum biogas and CH4 content was obtained. The co-digestion technique increased biogas and CH4 production by 111.3 and 173.6 %, respectively, over CD. On the 13th day, the maximum daily CH4 content was 67.11 %. During 60 days of anaerobic digestion (AD), the pH and volatile fatty acids (VFAs) concentrations fluctuated in an inverse proportion. Before and after the AD, there was a significant decrease in carbon/nitrogen (C/N). The vermicon identification technology (VIT®) gene probe indicated that co-digestion improved microbial population analyses, particularly for CH4-producing (Euryarchaeota) and acid-producing bacteria. According to the techno-economic evaluation, the maximum net energy content of biogas was 619.2 kWh/m3 with a net profit of 110.4 USD/m3 of substrate.