Experiment-based thermodynamic feasibility with co-digestion of nutrient-rich biowaste materials for biogas production.

Wild strains of algal biomass, a major contributor for eutrophication in freshwater bodies, can be used as a potential substrate in association with other nutrient-rich biowaste materials like animal excreta and industrial wastewater, for biogas production. This novel concept was experimentally evaluated and analyzed by the modified Gompertz equation for maximum biogas production (μm), lag phase (λ), and biogas yield (P). The value of correlation coefficient (R2) was 0.99 at varying temperature ranges (30, 40, and 50 °C). Thermodynamic functions like enthalpy (∆H), entropy (∆S), and Gibb's free energy (∆G) were evaluated for the chemical oxygen demand removal efficiency. Thermodynamic functions such as ∆G (-), ∆H (+), and ∆S (+) showed the spontaneous and endothermic nature of substrate degradation and biogas production was found to be increased with increasing temperature. So, this novel co-digestion approach using nutrient-rich biowaste materials provides a new insight into biogas production with the aim of waste-to-energy generation.