The performance of fermentation wastewater treatment in ultrafiltration membrane bioreactor by contiuous and intermittent aeration processes

A lab-scale experiment on the performance of highly concentrated activated sludge in high strength fermentation wastewater treatment with rotary disk type UF membrane was carried out. The experiment lasted 252 days and was operated under continuous and various intermittent aeration conditions. TOC and NH₄-N removals were quite good and intermittent aeration operations increased T-N removal efficiency. It demonstrated that activated sludge had strong ability for organic shock loading. However, the ability of nitrifier was weak compared with that of heterotrophic bacteria for pH shock. The activity of sludge in the reactor assessed by INT-dehydrogenase activity was not affected significantly after the incursion of anoxic operation, and the smaller coccus-like or rod-type bacteria (1-2μm) performed quite well for organic carbon and nitrogen removals.