Lab-scale methane fermentation using shrimp pond sludge and some available biomass on bên tre in vietnam

The Mekong Delta of Vietnam is rich in unutilized biomass resources such as sludge discharged from shrimp, catfish culture, residue of sugar production (bagasse and molasses) and coconut candy factory (coconut pomace), which have the potential to satisfy the local energy demand. Although many projects are focused on biofuel production from these biomass resources, not much attention has been paid to developing an efficient utilization technology. Therefore, we started the present study investigated the optimal conditions for methane fermentation to achieve stable biogas production from the biomass feedstock of the Mekong Delta in Vietnam. This is the first report of using methanogenic bacteria in the shrimp pond sludge for the digestion of bagasse, molasses and coconut pomace, which were available biomass near the methane fermenter constructed beside shrimp pond at Bên Tre in Vietnam. As a result of a continuous input test of bagasse and molasses, the H2S concentration in the collected gas was increased to 600 ppm and finally it had reached to 1,600 ppm by continuing to supply molasses. Therefore, an input test using coconut pomace instead of molasses was started. As a result, the generation of H2S was reduced to several tens ppm. After a 118-day acclimatization test, biogas was generated smoothly. After then, a methane fermentation test using bagasse and coconut pomace was started. As a result, in the 2nd fermentation test, adding a mixture of bagasse and coconut pomace (2: 3) at 10% VS with HRT80 resulted in biogas (4.03 L, 894 mL g-1VS)) equivalent to the effective volume of the fermenter (4 L).