Biogas production by anaerobic biodigestion of sewage sludge from sewage treatment plant: modeling and simulation

Anaerobic digestion has been identified as the optimal treatment method for high organic resistance waste when compared to alternative waste treatment methods. This is due to the fact that it facilitates the recovery of energy in the form of methane, while the treated sludge also demonstrates effective soil conditioning properties. The present study analyzes the anaerobic digestion reaction for treating sewage sludge, with the objective of modeling and simulating a non-ideal stirred tank reactor. In this study, a mathematical model for the reactor was developed, incorporating an ideal CSTR of volume Vs, a dead zone of volume Vd, and a bypass with volumetric flow Qb. The flow rate of the reactor, denoted by Q0, is measured and compared with the influent flow rate into the reactor, indicated by Qs. The model parameters are denoted by β, which represents the fraction of the total flow rate that undergoes bypass, and V, which represents the fraction of the total volume V occupied by the non-stagnant region. A comprehensive analysis was conducted on the model parameters and operating conditions of the reactor.