title: Nitrification resilience and community dynamics of ammonia-oxidizing bacteria with respect to ammonia loading shock in a nitrification reactor treating steel wastewater.
abstract: The aim of this study was to investigate the nitrification resilience pattern and examine the key ammonia-oxidizing bacteria (AOB) with respect to ammonia loading shocks (ALSs) in a nitrification bioreactor treating steel wastewater. The perturbation experiments were conducted in a 4-L bioreactor operated in continuous mode with a hydraulic retention time of 10 d. Three sequential ALSs were given to the bioreactor (120, 180 and 180 mg total ammonia nitrogen (TAN)/L. When the first shock was given, the nitrification process completely recovered after 14 d of further operation. However, the resilience duration was significantly reduced to ∼1 d after the second and third ALSs. In the bioreactor, Nitrosomonas aestuarii dominated the other AOB species, Nitrosomonas europaea and N. nitrosa, throughout the process. In addition, the population of N. aestuarii increased with ammonia utilization following each ALS; i.e., this species responded to acute ammonia overloadings by contributing to ammonia oxidation. This finding suggests that N. aestuarii could be exploited to achieve stable nitrification in industrial wastewaters that contain high concentrations of ammonia.
authors.affiliation: Center for Water Resource Cycle Research, Korea Institute of Science and Technology, 39-1 Hawolgok-Dong, Seongbuk-Gu, Seoul 136-791, Republic of Korea.
authors.forename: Kyungjin
authors.initials: K
authors.lastname: Cho
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea.
authors.forename: Seung Gu
authors.initials: SG
authors.lastname: Shin
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea.
authors.forename: Joonyeob
authors.initials: J
authors.lastname: Lee
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea.
authors.forename: Taewoan
authors.initials: T
authors.lastname: Koo
authors.affiliation: Department of Environmental Engineering, Kyungpook National University, 80 Daehak-ro, Buk-gu, Daegu 41566, Republic of Korea.
authors.forename: Woong
authors.initials: W
authors.lastname: Kim
authors.affiliation: School of Environmental Science and Engineering, Pohang University of Science and Technology, Pohang, Gyeongbuk 790-784, Republic of Korea. Electronic address: shwang@postech.ac.kr.
authors.forename: Seokhwan
authors.initials: S
authors.lastname: Hwang
mesh_terms: D000641:Ammonia / Q000378:metabolism*; D001419:Bacteria / Q000378:metabolism*; D019149:Bioreactors / Q000382:microbiology*; D058465:Nitrification; D009606:Nitrosomonas / Q000378:metabolism; D010084:Oxidation-Reduction; D013232:Steel; D013997:Time Factors; D062065:Wastewater / Q000737:chemistry*
chemical_list: D000641:Ammonia; D013232:Steel; D062065:Wastewater
keywords: Ammonia loading shock; Denaturing gradient gel electrophoresis; Nitrification; Quantitative PCR; Steel wastewater