Study on Operational Factors in a Nitrite-Accumulating Submerged Membrane Bioreactor

• Published in: Journal of microbiology and biotechnology Vol. 16; no. 3; pp. 469 - 474
• Main Authors: Yoo Ik-Keun, Lim Kyoung-Jo, Lee Won-Sik, Kim Dong-Jin, Cha Gi-Cheol
• Format: Journal Article
• Language: Korean
• Published: 2006
• Subjects: submerged membrane bioreactor; nitrite; suction pressure; nitrifier; FISH; Aeration rate
• ISSN: 1017-7825; 1738-8872

Partial nitrification blocking of the oxidation of nitrite ($NO_{2}^{-}$) to nitrate ($NO_{3}^{-}$) has cost-efficient advantages such as lower oxygen and organics demand for nitrification and denitrification, respectively. A nitrifying membrane bioreactor of submerged type was operated for the treatment of synthetic ammonium wastewater with the purpose of nitrite build-up without affecting the efficiency of ammonium oxidation. A high ammonium concentration (1,000 mg/l) was completely converted to nitrate at up to 2 kg $N/m^3$ day under sufficient aeration. The control of pH under sufficient aeration was not a reliable strategy to maintain stable nitrite build-up. When the dissolved oxygen concentration was kept at 0.2-0.4 mg/l by adjusting the aeration rate, about 70% of nitrite content was obtained with ammonium oxidation efficiency higher than 93%. The increase of suction pressure due to membrane fouling was not significant under lowered aerating environment over a 6-month period of operation. The composition of nitrifier community, including relative abundance of nitrite oxidizers in a nitrite-accumulating condition, was quantified by fluorescence in situ hybridization analysis.