Influence of mixed liquor recycle ratio and dissolved oxygen on performance of pre-denitrification submerged membrane bioreactors

Water Research
Teck Wee Tan, How Yong Ng

Abstract

The conflicting influence of mixed liquor recycle ratio and dissolved oxygen on nitrogen removal and membrane fouling of a pre-denitrification submerged MBR was investigated in this study. It was found that a high aeration rate of 10 L air/min was able to minimize membrane fouling as compared with lower aeration rates of 5 and 2.5L air/min in this study. Faster fouling at lower aeration rate was due to the decrease in cross-flow velocity across the membrane surface. However, high DO concentration (average of 5.1+/-0.5mg O2/L) present in the recycle mixed liquor at an aeration rate of 10 L air/min deteriorated the TN removal efficiency when operating at a recycle ratio of more than 3. A lower aeration rate of 5L air/min, resulting in an average DO concentration of 3.4+/-0.7 mg O2/L in the recycle mixed liquor, led to an improvement in TN removal efficiency: 63%, 80%, 84% and 89% for mixed liquor recycle ratio of 1, 3, 5 and 10, respectively. Further decrease in aeration rate to 2.5L air/min, resulting in an average DO concentration of 1.9+/-0.8 mg O2/L, did not improve the TN removal efficiency. Using a newly developed simplified nitrification-denitrification model, it was calculated that the COD/NO3(-)-N required for denitrific...Continue Reading

Citations

Nov 29, 2011·Environmental Science and Pollution Research International·Xiang-Yang XuHan-Ying Qi
Jan 21, 2015·Journal of Hazardous Materials·Faqian SunWeixiang Wu
Mar 10, 2018·Microbial Ecology·Dawen GaoHong Liang
Jun 12, 2019·Environmental Science and Pollution Research International·Hongxiang ChaiQiang He
Jun 16, 2017·Water Science and Technology : a Journal of the International Association on Water Pollution Research·Qibin WangJing Chen
Sep 19, 2018·International Journal of Environmental Research and Public Health·Wenlai XuZishen Mou
Dec 17, 2017·Applied Microbiology and Biotechnology·Han ChenFang Ma
Dec 18, 2020·International Journal of Environmental Research and Public Health·Massimo RaboniMaria Rosaria Boni

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