Using a novel continuous bioreactor in enhancing the biogas production

Abstract

Background: Since fossil fuels are limited and their burning is considered the main reason for environmental pollution, thinkers in the energy section are looking for a substitute for them. They have considered biogas as a potent replacement. Constant composition and volumetric rate, are ones of the challenges faced in term of using biogas. Therefore, in this study, a novel easily portable continuous bioreactor was designed and constructed to produce biogas at constant composition and volumetric rate, which is suitable for human uses. Sugar beet waste and anaerobic sludge were used as substrate and inoculum with an S/I ratio of 0.5 to 1, to produce biogas. Four parameters, i.e., hydraulic retention time (HRT), pH, biogas volume, and methane composition, were measured and compared.Results: The results of the mentioned reactor were compared with those of batch ones. The measurement revealed that the continuous reactor had a good performance on biogas purity and volumetric rate. The biogas contained about 53% methane. The suitable and preferable HRT and organic loading rate (OLR) were 18 days and 34.86 g VS/day. After the 18th day of operation, the biogas production process inside the continuous reactor was stable reaching about 411.2 ml STD/g VS per day.Conclusions: The reactor designed makes the biogas production process more manageable. Besides the production of the cumulative volume of biogas and constant methane percentage was achieved. As a result, the biogas produced is consumed daily, and a certain amount of gas is available every day. Since the percentage of gas produced is constant, it is possible to adjust the gas appliances with this amount of methane.

Changes in Microbiota Composition during the Anaerobic Digestion of Macroalgae in a Three-Stage Bioreactor

“…The VS and NS of raw materials are determined by the weight difference method. The loss mass is equal to VS, and the remaining mass is equal to NS [ 18 , 19 ].…”

Research on Biogas Yield from Macroalgae with Inoculants at Different Organic Loading Rates in a Three-Stage Bioreactor

“…In order to measure TS, a 5 g sample was taken and dried at 105 • C for 12 h. DS was determined knowing that it was equivalent to the humidity reading. For VS determination, the sample was placed in a muffle furnace and heated at a temperature of 550 • C for 1 h. The mass lost is equal to VS and the mass remaining is equal to NS [26,34]. The physical parameters of MA and inoculum are presented in Table 1.…”

“…In the chamber, the biomass is mixed and heated to a temperature of 20 • C. From AC-II, the substrate is fed to AC-III, where mesophilic conditions are maintained. Studies showed that methanogenesis works efficiently when the AC-III temperature is maintained at 37 • C [32][33][34]. The substrate from AC-III to AC-III does not adversely affect the methanogenic bacterial colonies that exist in AC-III.…”

“…The substrate is then mixed using a mechanical mixer and heated at 300 W/200 V. An industrial thermostat is used to adjust to the desired temperature. For this purpose, thermocouples were inserted into AC-II and AC-III in order to have contact with the substrate in the camera [34]. The mixer is equipped to mix AC-II and AC-III substrate at the same time.…”