Anna Schneider

• Some aspects of the anaerobic digestion (AD) process still remain unclear, basically due to complexity of microbial and physicochemical reaction. Thus, there is a need for understanding of the AD mechanisms which can improve stability and enhance the process performance. The process stability and velocity are influenced by the chemical composition of the feedstock and the full supply of the microbial community with essential elements. Modeling and simulation represents an appropriate analytical tool for studying and improving the biogas process generation and reduces the expenditure of time and cost for the laboratory experiments. A variety of biogas models contains unknown parameters and complex structure which makes the parameterization step difficult and requires many assumptions. In order to overcome this problem, in this study, a relatively simple model was formulated in order to represent accurately the dynamics of AD by adjusting three master substrates (proteins, carbohydrates and lipids). The model was calibrated using three sets of experimental data in batch: mono-fermentations of gelatine, sucrose and rapeseed oil. The parameterized model accurately predicts the AD of the substrates mixture of gelatine, sucrose and rapeseed oil for the volume of biogas and methane, the volumetric flow rate of biogas, the volumetric concentration dynamics of methane and the total chemical oxygen. Furthermore, the model was cross-validated by experimental data where potato waste water (PWW) and starch were digested and tested for two ways of the substrates replacement in continuous laboratory-scale biogas fermenter. The model accurately predicts the dynamics of the CH4 concentration and the volume of biogas.The developed model was adopted for the tank cascade system with the biogas fermenter at the end with total capacity of 2500 m3. We managed to generate the annual prognosis for continuous long-term the AD process only by arrangement of three components.