1. State Key Laboratory of Pollution Control and Resource Reuse, Key Laboratory of Yangtze River Water Environment, Ministry of Education, College of Environmental Science and Engineering, Tongji University, Shanghai 200092, China; 2. Shanghai Institute of Pollution Control and Ecological Security, Shanghai 200092, China
Abstract：The influencing characteristics and mechanisms of suspended carriers on nitrogen removal and membrane fouling were investigated by adding the carriers into a membrane bioreactor (MBR) inoculated with anaerobic ammonia oxidation (anammox) bacteria.The results showed that the reactor was of good nitrogen removal performance after adding the carriers.Both ammonia nitrogen (NH4+-N) and nitrite nitrogen (NO2--N) in the effluent were under 15mg/L,nitrate nitrogen (NO3--N) in the effluent was under 30mg/L,and total nitrogen removal efficiency reached 90%.Adding the carriers into the reactor effectively mitigated membrane fouling,and the transmembrane pressure (TMP) was stabilized at about 8kPa.The analyses results of soluble microbial products (SMP) and extracellular polymeric substances (EPS) in the mixed liquid showed that total amounts of proteins,polysaccharides and total organic carbon decreased by 49%,43% and 61%,respectively from day 67 to day 149,which was beneficial to mitigate membrane fouling.Besides,mechanical collision of the carriers onto the membrane modules also played a physical cleaning role.The high-throughput sequencing results showed that the relative abundance of anammox bacteria in the carrier biofilm was significantly higher than that in the mixed sludge,indicating that the anammox bacteria were more suitable for attachment growth,and the suspended carriers could provide a more stable growth environment for the community.
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