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

Abstract

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.