Abstract

Empirical Buswell’s equation for biomethane formation is a bioredox and bioenergy model for identifying the elemental composition, redox properties, and thermal properties of anaerobic digestate. The anaerobic digestion metrics for evaluating the degradability performance of organic matter such as biodegradability index, electron conversion efficiency, and energy conversion efficiency have already been developed. In this research, the theoretical and experimental heat of bioredox in anaerobic digestion are quantified, in which calculations are demonstrated by step-by-step procedures. Then the relationships between the established heat of bioredox conversion efficiency in anaerobic digestion and pre-existing anaerobic digestion metrics are bridged. The research finds out that: (i) both theoretical and experimental heat of anaerobic digestion are equal to zero, (ii) both theoretical and experimental heat of bioredox in anaerobic digestion are less than zero, (iii) heat of bioredox conversion efficiency in anaerobic digestion is identical to its biodegradability index and electron conversion efficiency, (iv) when higher heating value of organic matter is counted by the modified Dulong formula, heat of bioredox conversion efficiency in anaerobic digestion is not equal to energy conversion efficiency, (v) when higher heating value of organic matter is counted by the theoretical higher heating formula, heat of bioredox conversion efficiency in anaerobic digestion is equal to energy conversion efficiency, and (vi) empirical Buswell’s equation can be used as a device to validate the experimental biomethane potential of organic matter and empirical formula of anaerobic digestate.

This work is licensed under a Creative Commons Attribution 4.0 License.