Roles of sponge sizes and membrane types in a single stage sponge-submerged membrane bioreactor for improving nutrient removal from wastewater for reuse

Sponge not only can reduce membrane fouling by means of mechanical cleaning and maintain a balance of suspended-attached microorganisms in submerged membrane bioreactor (SMBR), but also can enhance dissolved organic matter and nutrient removal. This study investigated the performance of three different sizes of sponge (S28-30/45R, S28-30/60R and S28-30/90R) associated with continuous aerated SMBR. A laboratory-scale single stage sponge-SMBR (SSMBR) showed high performance for removing dissolved organic matter (>96%) and PO4-P (>98.8), while coarse sponges such as S28-30/45R, S28-30/60R could achieve more than 99% removal of NH4-N. When three-size sponges (S28-30/45R, S28-30/60R and S28-30/90R) were mixed at a ratio of 1:1:1 and in conjunction with two kinds of membranes (0.1 μm hollow fiber and 2 μm nonwoven), the SSMBR system has proved its generic merits of superior treated effluent quality and less membrane fouling. The NH4-N and PO4-P removal were found excellent, which were more than 99.8% and over 99% respectively. Molecular weight distribution also indicated that major fractions of organic matter could be successfully removed by SSMBR. © 2009 Elsevier B.V. All rights reserved

Application of bioflocculant and nonwoven supporting media for better biological nutrient removal and fouling control in a submerged MBR

© 2011, Chinese Institute of Environmental Engineering. All rights reserved. The study aims at modifying a submerged membrane bioreactor (SMBR) with attached-growth nonwoven media and a new green bioflocculant (GBF) (developed at Environmental Engineering R & D laboratory, University of Technology, Sydney) addition to treat a high strength domestic wastewater for reuse. The performance of the SMBR was evaluated in terms of organic and nutrient removal as well as membrane fouling control. The results indicated that the integrated SMBR system could eliminate more than 95% dissolved organic carbon and chemical oxygen demand from the influent. The system achieved 100% of nitrification during 60 d of operation. The denitrification was primarily based on conventional nitrification-denitrification process occurring in the anoxic zone. The total nitrogen removal efficiency and simultaneous nitrification and denitrification were 93 ± 3 and 96 ± 1% respectively. Although a relatively long solids retention time (50 d) were adopted, over 98% of total phosphorus in the influent was removed through biological phosphorus removal. The results also show that the addition of GBF could improve microbial activity and reduce membrane fouling. During the experiment, the transmembrane pressure developed marginally (4.5 kPa)