Use of ADM1 model to simulate the anaerobic digestion process used for sludge waste treatment in thermophilic conditions

ADM1 model of IWA is still applied to a pilot scale anaerobic digestion process for the treatment of the waste activated sludge originating from a municipal wastewater treatment plant. This operation is carried out in a digester of 500 L volume. It is operated at an average hydraulic retention time (HRT) of 20 days with an average organic loading rate (OLR) of 1.27 kgTVS/m3 day, at a temperature of 55 ◦C with an average gas production rate (GPR) of 0.39 m3/m3 day. The aim of the present study was to compare the results obtained from the simulation with the experimental values. ADM1 makes use of the experimental results for the optimization of the different kinetic parameters values. Generally, the simulated results are in a reasonably good fit for pH, methane and carbon dioxide percentages, biogas volume, chemical oxygen demand (COD), and total volatile fatty acids (TVFA). However, deviations are shown with an underestimation for the soluble chemical oxygen demand (SCOD) and inorganic carbon (IC) and an overestimation of inorganic nitrogen (IN).