ISSN 2384-5058
Biogas technology converts organic trash (substrate) into energy while also enhancing the environment and human well-being. Design of bioprocess for biogas production requires empirical/kinetic models for proper sizing of equipment and control of process variables. This work focuses on the determination of Gompertz model parameters for sheep excrement, leftover tomatoes, chicken droppings, and leftover fluted pumpkin leaves as substrates. The biogas produced had an average composition of 65.34 mol% methane and 22.81 mol% carbon dioxide; other components included hydrogen 7.49 mol% and nitrogen 3.39 mol%, as well as tiny amounts of water vapor and carbon monoxide. Hydrogen sulphide was not found. The cumulative volume–time data obtained was fitted into the Gompertz model founded on non-linear regression analysis with Microsoft Excel's Solver program. Gompertz model provided high cross-correlation coefficients of 0.997, 0.996, 0.997 and 0.993 for tomato waste, chicken droppings, Fluted Pumpkin Leaves Waste, and sheep manure respectively.
Keywords: Empirical model, Gompertz model, Non-linear regression, substrate, biogas production.