Bioethanol is renewable energy produced from agricultural feedstock and thus bioethanol has been attracting attention as an alternative fuel for gasoline. However, bioethanol produces massive amount of waste/wastewater during the production process. These waste/wastewater are fermentation waste, distillery waste and washing wastewater. The characteristics of the wastewater are high-concentration of organic matters and nitrogen; in addition it has blackish brown color comes form low degradability pigments such as melanoidin or caramel. To treat the bioethanol producing wastewater, we are focusing on a combination of biological treatment that remove organic matters and membrane treatment that remove pigment. The former biological treatment have key role in whole treatment system for the wastewater.
So in this study, we have been developing the UASB+DHS+ASB (anaerobic sludge bed) system as a biological treatment system; UASB for removal of organic matter, DHS for removal of residual organic matter and nitrification, ASB for denitrification.