To attain high loading and stable methanogenesis,approaches such as the use of a two-stage system,a packed-bed or fixed-bed system, additives such as inorgabnic elements,and co-digestion with other organic wastes are used for garbage treatment(Mata-Alvarez et.2000;Yadvika et al.2004;Tatara et al.2004,2008;Angeludaki et al.2006;Sasaki et al.2006-2007;Ueno et al.2007a;Umana et.2008).The aim of this review is to describe such approaches that influence the degradation of gar-bage and the production of methane gas.Special focus is given to the effect of the relation between electron balance and the microbial communities in the methanogenic bioreactor.