Combination of batch experiments with continuous reactor data for ADM1 calibration: application to anaerobic digestion of pig slurry Available to Purchase

Modelling anaerobic digestion processes is a key aspect of studying and optimizing digesters and related waste streams. However, for the satisfactory prediction of biogas production and effluent characteristics, some parameters have to be calibrated according to the characteristics of the substrates. This article describes a calibration procedure for the IWA ‘Anaerobic Digestion Model no. 1’ applied to the modelling of a digester for treatment of pig slurry. The most sensitive parameters were selected and calibrated combining results from a continuous digester and from batch trials run with the sludge sampled from the digester and the addition of specific substrates. According to the sensitivity analysis, acetoclastic methanogenesis, acetogenesis of propionate and acidogenesis of sugars were identified as the main sensitive steps in our case. The calibration procedure led us to modify slightly acetogenesis of propionate kinetic. However, acetoclastic methanogenesis and acidogenesis of sugars kinetics were significantly reduced by decreasing k_m and increasing K_s. Indeed, for instance, a decrease of k_{m_ac} from 8 to 7 day⁻¹ combined with an increase of K_{s_ac} from 0.15 to 1.5 kgCOD/m³ was necessary. After calibration, ADM1 provides an accurate simulation of the continuous reactor results.