Characterization of nitrifying granules produced in an aerobic upflow fluidized bed reactor

Tsuneda, Satoshi; Nagano, Tatsuo; Hoshino, Takao; Ejiri, Y.; Noda, Naohiro; Hirata, Akira

doi:10.1016/j.watres.2003.08.017

Cited by 179 publications

(115 citation statements)

References 33 publications

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“…These species could do respiration using nitrate as the electron accepter when oxygen is limited and it is speculated that they grew on the EPS formed by active nitrifiers and dead cells. Tsuneda et al (2003) also reported the development of heterotrophs inside the nitrifying granules although the organic matter was not contained in the feed solution.…”

Section: Quinone Profilesmentioning

confidence: 99%

Nitrification performance and microbial community dynamics in a submerged membrane bioreactor with complete sludge retention

Yang

Zhang

et al. 2006

Journal of Biotechnology

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A submerged membrane bioreactor (MBR) supplied with inorganic ammonium-bearing wastewater (NH 4 + -N, 500 mg l −1 ) was operated for 260 days without sludge purge under decreased hydraulic retention times (HRT) through six steps (from 30 to 5 h). Almost complete nitrification was obtained at a volumetric loading rate (VLR) 1.2 g NH 4 + -N l −1 day −1 . The sludge nitrification activities were evaluated at each stage. The specific ammonium oxidizing rate (SAOR) decreased from the initial 0.45 to 0.15 kg NH 4 + -N kg −1 MLSS day −1 in the last four stages, while the specific nitrate forming rate (SNFR) increased from 0.17 to 0.39 kg NO 3 − -N kg −1 MLSS day −1 at the third stage, and then decreased to below 0.1 kg NO 3from the fourth stage. Microbial population dynamics was investigated by a combination of the MPN method, fluorescence in situ hybridization (FISH) and quinone profiles. During the experiment, although the MLSS increased gradually from 4.5 to 11.5 g l −1 , the number of ammonia-oxidizing bacteria (AOB) decreased from 10 9 l −1 at the third stage to 10 7 l −1 in the last two stages, and that of nitrite-oxidizing bacteria (NOB) decreased gradually from 10 8 l −1 at the second stage (HRT of 20 h) to the final 10 5 l −1 . FISH results showed that the active cells decreased gradually with time from about 60 to 20% in the last two stages, and most of sludge was inert cells. The sum of nitrifiers occupied only about 10% of the total bacteria number in the last stage even though only ammonium-bearing inorganic wastewater was fed in. Nitrosomonas sp. and Nitrospira sp. were confirmed by FISH as the dominant nitrifying genera responsible for ammonia and nitrite oxidation, respectively. In the mean time, a small ratio of Nitrobacter sp. also existed in the system. FISH analysis matched better with the batch activity test results than did the MPN techniques. Quinone profiles revealed that the dominant ubiquinone was ubiquinone-8 (UQ-8), ranging from 84 to 66%, followed by UQ-10 of 7-13%, UQ-7 of 3-5% and UQ-9 of 1.6-2.6%. The dominant menaquinone in the MBR was menaquinone-7 (MK-7) followed by MK-6, MK-8 and MK-8 (H 2 ). With the prolongation of operation, the percentage of menaquinones increased from 8 to 14%. The use of the polyphasic approach gave some new insight on variations of microbial community structures.

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Section: Quinone Profilesmentioning

confidence: 99%

Nitrification performance and microbial community dynamics in a submerged membrane bioreactor with complete sludge retention

Yang

Zhang

et al. 2006

Journal of Biotechnology

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“…In the experiment, the stabilization of the fluidized state during the operation process will be mainly considered, thus the third process is the most important. In the below, the change rule of flow resistance in tubes of inert particle fluidized bed evaporator will be studied [35][36][37][38][39].…”

Section: Pressure Drop Model Of Inert Particle Fluidized Bed Evaporatormentioning

confidence: 99%

Experimental Study on Hydrodynamic Performance and Heat Transfer Mechanism of Vapor-liquid-solid Three-Phase Fluidized Bed

Guo¹,

Qi²,

Zheng³

et al. 2016

IJHT

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In consideration of the characteristics of vapor-liquid-solid three-phase fluidized bed, this evaporator is applied in the liquid food-green tea extraction liquid concentration/evaporation process in this paper. The inert particles fluidized bed evaporation experiment device is designed and built combined with the characteristics of food material concentration. In this experiment, the heat transfer mechanism and hydrodynamic performance of inert particles fluidized bed evaporator during extraction of concentrated green tea are studied, and the impact of various experimental operation parameters on the evaporation and heat transfer performance as well as pressure dropping is analyzed. Moreover, the dimensionless analysis method is used to establish a correlation formula between the heat transfer coefficient and pressure drop dimensionless number of inert particle fluidized bed evaporator according to the characteristics of inert particles fluidized bed. In addition, the fouling prevention and descaling property and hydrodynamic performance of inert particle fluidized bed evaporator are studied, providing practical significance for industrial production.

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“…In traditional biological nitrogen removal system, nitrifying bacteria was characterized by slow growth rate and high sensitivity to both toxic compounds and unfavorable environmental conditions. However, nitrifying granules, as aggregates of nitrifying bacteria, have been proved effective in enhancing nitrification rate and system stability by the high retention of nitrifying bacteria [6]- [9].…”

Section: Introductionmentioning

confidence: 99%

“…Tsuneda proved that nitrifying bacteria able to treat ammonia nitrogen as high as 500 mg N/L could be self-immobilized in an aerobic upflow fluidized reactor, with nitrifying granules of 350 μm in diameter produced after 300 days of operation [6]. Liu cultivated nitrifying granules with size of 240 μm and SVI of 40 mg/L on day 21 in SBR, which was able to treat 450 mg N/L of ammonia [8].…”

Section: Introductionmentioning

confidence: 99%

Formation and Stability of Nitrifying Granules under High Loading Rates

Wang¹,

Chen²,

Nie³

et al. 2016

IPCBEE

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Abstract. Nitrifying granules are generally believed to have high nitrification ability due to the immobilization of large quantities of nitrifying bacteria with low growth rate. However, high loading rate is normally not recommended for nitrifying granules due to the high inhibition statue. In this study, nitrifying granules, able to treat ammonia nitrogen as high as 1000 mg N/L (2 kg N/m 3 ·d), were cultivated in the laboratory scale sequencing batch reactor. During around 200-day operation, the granules exhibited good performance with 99% ammonia removal efficiency. In the meantime, MLSS increased from initial 6 g/L to the final 10 g/L, and the value of SVI 30 decreased from around 100 to 15 ml/g. However, it was observed that the nitrifying granules gradually disintegrated into small aggregates with mean size decreased from 286 to 138 μm from the operation day 50 to 120, after which they gradually recovered by themselves with increased mean size of 235 μm at the end of the operation. Notably, this disintegration did not compromise performance and characteristics of the nitrifying granules. These results demonstrated that nitrifying granules may have the capability to undertake ammonia loading rates as high as 1000 mg N/L with good self-healing ability, which make the process more stable and promising in practice.

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Characterization of nitrifying granules produced in an aerobic upflow fluidized bed reactor

Cited by 179 publications

References 33 publications

Nitrification performance and microbial community dynamics in a submerged membrane bioreactor with complete sludge retention

Nitrification performance and microbial community dynamics in a submerged membrane bioreactor with complete sludge retention

Experimental Study on Hydrodynamic Performance and Heat Transfer Mechanism of Vapor-liquid-solid Three-Phase Fluidized Bed

Formation and Stability of Nitrifying Granules under High Loading Rates

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