THEORETICAL COMPARATIVE STUDIES OF THE BIOGAZ YIELDS FROM ONE-STAGE AND TWO-STAGE ANAEROBIC DIGESTION PROCESSES

Abstract

This paper deals with the theoretical comparison of biogas and energy yields of one-stage anaerobic digestion processes (OSAD) with biomethane production and two-stage anaerobic digestion processes (TSAD) producing biohydrogen and biomethane. The comparative study of the biogas yield from OSAD and TSAD systems is performed on the base on mathematical models obtained in our previous papers. The possible maximal yields of biohydrogen and biomethane are calculated by the static characteristics and extremum points of both systems. Simulation results suggest that in comparison to OSAD, the increase in biogas (biohydrogen and biomethgane) production of TSAD can reach to 75.18%. The energy produced from two-stage anaerobic digestion processes is 1.32 to 1.486 times greater than those from one-stage anaerobic digestion processes (depending of the inlet organics concentrations), which means TSAD is a better choice considering biogas and energy production.