Abstract
Specific methane production activities (SMPAs) of methanogenic bacteria attached on carriers in a pilot-scale two-phase anaerobic membrane reactor were investigated. In the process a membrane was placed between acidification and methane reactors. The plant treated continuously a soybean processing wastewater. Vial tests were conducted using six different substrates and bacteria grown in each fixed bed reactor. The test results are shown as follows ;
1) Bacteria attached on the methane reactor carriers showed higher SMPAs than those of bacteria in the acidification reactor in case of using formate, acetate, propionate or butyrate as a substrate.
2) A SMPA of ethanol decomposition revealed an extremely high value concerning bacteria in the acidification reactor. It was assessed that metabolic groups of bacteria converting ethanol to methane played an important role in the acidification reactor.
3) In comparison with SMPAs of UASB granules in the literature, methane reactor bacteria had almost equal or higher SMPAs and demonstrated a similarity ot UASB granules cultured by a mixture of organic acids, Hence, the methanogenic consortia similar to those in UASB granules were estimated to be present on the carriers in the existing methane reactor.
