Using a novel continuous bioreactor in enhancing the biogas production

Since fossil fuel resources are depleting and their consumption is associated with environmental pollution, researchers in the energy section are searching for a proper alternative. Biogas is one of these potent replacements. Constant composition and volumetric rate are some of the challenges in using biogas. In this study, a novel, easily portable continuous bioreactor was designed and constructed to produce biogas at constant composition and volumetric rate for human uses. Sugar beet waste and anaerobic sludge were used as substrate and inoculum to produce biogas, respectively. Five parameters, i.e., hydraulic retention time (HRT), organic loading rate (OLR), pH, biogas volume, and methane composition, were measured and compared. The results obtained from the continuous bioreactor were compared with the results obtained from the batch reactors under the same operating conditions. The measurement revealed that the continuous reactor had an excellent performance in terms of biogas purity and volumetric rate. The suitable and preferable HRT and OLR were 18 days and 34.86 g VS/day, respectively. After 18 days of operation (start-up period), the biogas production process inside the continuous bioreactor was stable, reaching about 411.2 mL STD/g VS per day. The unique design of the horizontal continuous bioreactor makes it possible to convert biodegradable wastes to biogas quickly. Also, the biogas from the continuous bioreactor contained about 53% methane without any purification process at suitable conditions, i.e., TS = 8.35%.

Automated summary

In this study, a novel portable continuous bioreactor was designed and constructed to produce biogas at constant composition and volumetric rate. The performance of the continuous bioreactor was compared with batch reactors, and it showed excellent biogas purity and volumetric rate. The suitable hydraulic retention time and organic loading rate were determined, and the continuous reactor successfully converted biodegradable wastes to biogas.