Abstract
Biogas is an alternative, renewable fuel produced from the anaerobic digestion (AD) of organic matter. There were three objectives to this study: (i) determine the biogas production and organic matter consumed during the anaerobic digestion of cow manure (CM), water hyacinths (WH), and their mixtures, (ii) fit the Time-Lag and Modified Gompertz models to the results and assess their fits, (iii) compare the yields to those predicted by the Buswell, Mueller, and Boyle stoichiometric formula. The average biogas production for the CM monodigestion tests, WH monodigestion tests, and CM and WH co-digestion tests were 193.72 ± 51.98 mL biogas/g VS, 49.99 ± 22.28 mL biogas/g VS, and 169.70 ± 82.57 mL biogas/g VS, respectively. The Modified Gompertz model tended to fit the biogas production results better than the Time-Lag model but the uncertainty in the fits were also large. The average theoretical yield for all tests was 25.91 ± 30.11%.