Optimization of methane production process from synthetic glucose feed in a multi-stage anaerobic bioreactor

Abstract

A B S T R A C TThe biological conversion of biomass into methane during anaerobic digestion has been studied by many researchers in recent years. In this study, optimization of methane composition during chemical oxygen demand removal was observed in a multi-stage Anaerobic Bioreactor. Synthetic glucose was used as a feed substrate, and the reactor was operated at a hydraulic retention time (HRT) of 1-4 d. Complementary experimental and theoretical test procedures were evaluated for methane optimization. The theoretical methane was recorded as 50.13, 50.02, 50.16, and 50.22% for an HRT of 4, 3, 2, and 1 d, respectively. However, the quantity of methane determined experimentally was significantly lower than the theoretical predictions; this was likely due to the microorganism activity in the reactor that may have interfered with the efficiency of the biogas generation. Experimental data showed a decrease in the methane composition (35.4, 21.2, 19.8, and 18.4% for HRT of 4, 3, 2, and 1 d, respectively) in the reactor system. Thus, the theoretical formula and experimental data together provide an alternative method for the evaluation of bioenergy potential in anaerobic digestion.

Review of Upflow Anaerobic Sludge Blanket Reactor Technology: Effect of Different Parameters and Developments for Domestic Wastewater Treatment

“…However, some of the gas produced in the sludge blanket is attached to the granules, and a gas-liquid-solid separator (GLSS) is added on the top of the reactor for the effective segregation of gas, liquid, and granules. In GLSS, the gas surrounded particles strike with the bottom of degassing baffles and fall back into the sludge blanket and the treated water flows out of the reactor [21,26,27]. There is lower gas production in sewage as compared to high strength wastewater, which leads to less circulation of gas to support the formation of biological granules.…”

“…In case of sewage, the OLR usually is applied in the range of 1.0-2.0 KgCOD/m 3 ⋅day [42,101]. UASB reactor is preferred for its potential to treat wastewater having low content of suspended solids and gives higher methane yield [27]. The reactors seeded with granular activated sludge can give high performance within a brief startup period and can also adapt quickly to increase of OLR [25].…”

“…Consequently, a high sludge loading rate (SLR) could be applied (up to 5 gCODgVSS −1 day −1 ) with a relatively short HRT, less than 4 hours [25]. Formation of activated sludge is important, in either granular or flocculent form, in the reactor which ensures adequate removal efficiency even at high OLR [27].…”