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Pantip Kayee,Chaiwat Rongsayamanont,Pattaraporn Kunapongkiti,Tawan Limpiyakorn 대한환경공학회 2016 Environmental Engineering Research Vol.21 No.2
Owing to the kinetic differences in ammonia oxidation among ammonia-oxidizing microorganisms (AOM), there is no standard set of kinetic values that can be used as a representative set for nitrifying wastewater treatment plant (WWTP) design. As a result, this study clarified a link between the half-saturation constants for ammonia oxidation (Ks) and the dominant ammonia-oxidizing bacterial (AOB) groups in sludge from full-scale WWTPs and laboratory-scale nitrifying reactors. Quantitative polymerase chain reaction analyses revealed that AOB affiliated with the Nitrosomonas oligotropha cluster were the dominant AOM groups in the sludge taken from the low-ammonia-level WWTPs, while AOB associate with the Nitrosomonas europaea cluster comprised the majority of AOM groups in the sludge taken from the high-ammonia-level WWTPs and nitrifying reactors. A respirometric assay demonstrated that the ammonia Ks values for the high-ammonia- level WWTPs and nitrifying reactors were higher than those of the low-ammonia-level plants. Using the Ks values of available AOM cultures as a reference, the Ks values of the analyzed sludge were mainly influenced by the dominant AOB species. These findings implied that.different sets of kinetic values may be required for WWTPs with different dominant AOM species for more accurate WWTP design and operations.
Application of cell immobilization technology to promote nitritation: A review
Pattaraporn Kunapongkiti,Chaiwat Rongsayamanont,Panida Nayramitsattha,Tawan Limpiyakorn 대한환경공학회 2020 Environmental Engineering Research Vol.25 No.6
Nitritation, the oxidation of ammonia to nitrite without subsequent oxidation to nitrate, is a starting step for nitrite-based nitrogen removal approaches. This process can be induced by maintaining specific operating conditions that facilitate ammonia oxidation but deteriorate nitrite oxidation. In recent years, a number of publications have demonstrated the ability of cell immobilization to maintain nitritation and an oxygen-limiting strategy was suggested to be a key to the success of the approach. However, several aspects related to the success and failure of such systems remains unclear and requires further in-depth clarification. This review provides current information on the utilization of cell immobilization in nitritation reactors. Common operating strategies that promote nitritation by controlling environmental conditions are summarized in the first part of the review. The application of cell immobilization, including cell attachment, cell granulation, and cell entrapment systems, as well as microenvironments, and microbial distributions within cell immobilization matrices, are elaborated in the middle part of the review. Problems encountered in the operation of nitritation reactors using cell immobilization are discussed as opportunities for further research at the end of the review.
Importance of culture history on 17α-ethinylestradiol cometabolism by nitrifying sludge
Angkana Jantanaprasartporn,Suppasil Maneerat,Chaiwat Rongsayamanont 대한환경공학회 2018 Environmental Engineering Research Vol.23 No.1
17α-ethinylestradiol (EE2), a synthetic estrogen which interfere the endocrine and reproductive function in living organisms, has been found extensively to be deposited into municipal wastewater treatment plants and the environment via human excretion. EE2 has long been known to be efficiently cometabolized by ammonia-oxidizing bacteria (AOB) during ammonia (NH₃) oxidation. Current study aims to investigate the effect of culture history on the biotransformation of EE2 by nitrifying sludge which was enriched under different ammonia loading rates in continuous flow reactors. Result showed that past growth condition largely affected not only the metabolic rate of NH₃ oxidation but also EE2 cometabolism. Sludge previously acclimated with higher NH₃ loads as well as sludge dominated with AOB belong to high growth cluster (Nitrosomonas europaea-Nitrosococcus mobilis) showed higher rate of EE2 biotransformation than those one being acclimated with lower NH₃ loads because of its ability to provide more reducing power from NH₃ oxidation. Moreover, the correlation between the degradation rates of NH₃ and EE2 was higher in sludge being acclimated with higher load of NH₃ in comparison with other sludge. Implication of the findings emphasized the role of volumetric NH₃ loading rate in determining EE2 removal in wastewater treatment system.