According to [5], there are different types of reactors used for energy recovery from solid wastes,
including batch reactors, one stage and two stage reactors. In batch reactors, wastes are fed in to the
system and all the degradation steps are allowed to follow sequentially. In one stage systems which are
commonly preferred for full scale anaerobic digestion of organic solid wastes in the world, all the
reactions simultaneously take place in a single reactor. In two stage systems, two different reactors areused for acidogenesis and methanogenesis. One stage systems are preferred than the batch and two stage
systems because of their easier and simpler designs and low in investment costs