Estimation of Methane Yields in Continuous Biogas Reactors Using Kinetic and Mass Flow Models

The measurement of methane potential during anaerobic digestion has generally been accomplished through batch assays. Yet, the majority of industrial plants employ a semi‐continuous feeding regime and the estimation of continuous process yield from batch data is not straightforward due to differences in kinetic rates. A simple method is examined whereby batch assays were set up with very high inoculum‐to‐substrate ratios (I:S) and the results applied to a model of mass flow through a continuous process. The results demonstrate that high I:S batch assays estimated the continuous process yield to within 2.5 % of the measured value.