Performance evaluation of the main kinetic models applied in anaerobic co-digestion process: description of synergistic effect of total solids concentration and particle size in biogas production

Abstract The present study investigated the kinetic modeling of anaerobic co-digestion under the optics of Modified Gompertz, Function transfer, Logistic function, Modified first order, and Cone models. As substrate, vegetables and fruits solid waste (VSW) and anaerobic sewage sludge (ASS) were used. The synergistic effects of substrate particle size (SPS) and total solids (TS) concentration were investigated. With the application of the Akaike information criterion (AIC) and the NRMSE it was possible to determine the performance order of performance of the models: Logistic function > Cone > Modified 1st order > Modified Gompertz > Function transfer. The biogas production and kinetic parameters predicted by Logistic function model reached the maximum likelihood in relation to the experimental result (AIC 36; NRMSE 43.292). SPS had a statistic significant effect on the cumulative biogas (Mmax) yield and on the hydrolysis constant (K’’hyd). In turn, the TS concentration influenced the latency phase time (λ) and the maximum rate of biogas production (Rmax).