(82b) Biogas Production and Hydrogen Gas Injection Effect in Expanded Granular Sludge Bed Reactor Under Thermophilic Temperature Range

The biogas produced from the anaerobic digestion process could be utilized generally in all the equipment that use natural gas for operation with a minimum adjustment for the lower BTU content of the biogas. Using the EGSB reactor, which is the updated version of the up-flow anaerobic sludge blanket (UASB) under thermophilic range will accelerate the process and rise the biogas production more than operating under other temperature ranges. Generally, there are three different temperature ranges, psychrophilic, mesophilic, and thermophilic ranges. Increasing the temperature will increase the activity of the microorganisms that reside inside the biomass granular particles until it reaches the optimum. However, increasing the temperature above that would cause instability for the microorganisms and reduce the biogas production rate. Hydrogen gas that produced from the first stage of the anaerobic digestion could be utilized and injected back to the EGSB. The hydrogen consuming methanogenic bacteria would start consuming the hydrogen gas as well as the carbon dioxide produced from the first stage and generate methane gas. In this approach, the biogas produced will be enhanced quantitatively and qualitatively. The amount of the hydrogen gas injection will be lower than the consumption ability of the microorganisms in order not to cause inhibition inside the reactor due to the pH drop.