Kinetic Modeling and Energy Optimization of Biogas Production from Slaughterhouse Waste in Forest Guinea

Anaerobic digestion of slaughterhouse waste can mitigate pollution while supplying locally usable energy. Final biogas volume alone, however, does not define a rational operating time. This study modeled daily kinetics from four experimental loads monitored for 40 days in N’Zérékoré: diluted rumen content (D1), blood (D2), rumen content-pig slurry (D3), and a more concentrated rumen-content treatment (D4). First-order, modified Gompertz, logistic, and Cone models were fitted by nonlinear least squares to daily increments and compared using corrected Akaike information criterion, RMSE, MAE, , and residual diagnostics. Fitting uncertainty was assessed using 1,000 moving-block bootstrap repl icates. An operational threshold,, was defined as the modeled time required to recover 90% of the biogas energy observed on day 40. Recalculated cumulative volumes were 2,432, 3,415, 795, and 2,492 mL per experimental load for (D1)-(D4). The Cone model was selected for (D1) and (D4), whereas the modified Gompertz model best described (D2) and (D3). Estimated values were 16.84, 19.39, 35.80, and 28.53 days, respectively. Using methane fractions reported in the source study and a methane lower heating value of 9.94 kWh/, apparent gross energies were 15.92, 23.17, 4.51, and 16.31 Wh per load. (D2) combined the highest total energy with an energy productivity of 1.075 Wh/day at . The proposed operating times would shorten digester occupancy by 57.9%, 51.5%, 10.5%, and 28.7% relative to a fixed 40-day cycle. These estimates provide a numerical decision aid for cycle duration, rather than causal optimization of operating variables, because the dataset includes no biological replicates, blank controls, or factorial design.