Comparative optimisation of biohythane production from starch wastewater by one-stage and two-stage anaerobic digestion

Now, energy crisis was the problem in the world. This research was study the biohythane production for renewable energy. The experiment was optimised using starch by one-stage and two-stage anaerobic digestion in batch reactor. For two-stage, the optimal conditions of biohythane production were pH 7.0, thermophilic temperature, C/N ratio 30 for a first step (hydrogen yield 63.65 mL H2/g COD) and pH 7.5, thermophilic temperature, C/N ratio 30 for a second step (methane yield 184.59 mL CH4/g COD). Furthermore, one-stage was achieved at an initial pH 7.5 under thermophilic temperature and C/N ratio 30 (methane yield 206.47 mL CH4/g COD). At optimal conditions, the maximum COD removal of two-stage (73.75%) was higher than that of one-stage (68.70%). Overall bioenergy recovery of two-stage was more generation than that of one-stage, including utilisation of organic matter at the same time.