Performance of a hybrid membrane aerated biofilm reactor (H-MBfR) for shortcut nitrification

Abstract

Membrane fouling, especially that caused by microbes is the main reason restricting the application of membrane technology in wastewater treatment. In this study, shortcut nitrification (SN) of ammonia was achieved in a new hybrid membrane aerated biofilm reactor (H-MBfR) where fixed fiberfill was used as the auxiliary biofilm carrier to alleviate membrane fouling through most biomass transfer. The experiment showed that the NO2− accumulation capacity of the reactor was stable and that the NAE was greater than 80 %. The oxygen transfer efficiency reached 71.09 % because the membrane module was used to provide oxygen to the reactor. Microbial community analysis showed that the percentages of Nitrosomonas in the two biofilm-samples collected from the membrane and fiberfill were 37.47 % and 10.99 %, respectively. Microorganisms in the reactor mainly concentrated on the fiberfill, and the biomass on the surface of the membrane accounted for only 19.53 % of the total biomass. The results indicated that the addition of fiberfill effectively improved membrane fouling by reducing the biomass on the membrane surface. This research makes possible the practical application of the SN process and is an insightful method for meeting the challenge of membrane fouling.