In this research, cattle manure, macroalgae, and cheese whey were mixed in various proportions (cattle manure:macroalgae:cheese whey ratios of 50:30:20, 30:20:50 and 20:50:30) and subjected to co-digestion under laboratory conditions at two different digestion temperatures (30 and 45 °C). The modified Gompertz and first-order kinetic models were used to predict biomethane potentials. The highest experimental biochemical methane potential of 0.373 Nm3CH4/kgVS was obtained from Mixture-2 at 45 °C, while the lowest, 0.154 Nm3CH4/kgVS, was achieved with Mixture-1 at 30 °C. Feedstock rates in the mixture and digestion temperature significantly influenced the biochemical methane potential (p < 0.05). Cheese whey was observed to positively contribute to increasing biomethane potential. Increasing the whey ratio in the mixture from 20% to 50% resulted in a 62.5% increase in biomethane production. While R2 values for the modified Gompertz model ranged from 0.993 to 0.999, those of the first-order model varied between 0.968 and 0.984. Of the two kinetic models employed for estimating biomethane potentials, the modified Gompertz model yielded values closer to the experimental biomethane potentials.
Figen Taşcı Durgut (Sat,) studied this question.