• Title, Summary, Keyword: nitrification

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Study on the Characteristics of Nitrification and Denitrification using Attached Microorganism (부착성 미생물을 이용한 질산화 및 탈질특성에 관한 연구)

  • Kwon, Moonsun;Lee, Euisin
    • Journal of Korean Society of Water and Wastewater
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    • v.8 no.3
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    • pp.19-25
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    • 1994
  • In this research, characteristics of nitrification and denitrification using the microorganism attached on sponge and plates were examined. The denitrification and nitrification performance were investigated under the anaerobic and aerobic condition for about 2 months. Because the basins of denitrification and nitrification were connected in series, wastewater was flowed from denitrification basin to nitrification one. The 90% of influent flowrate was returned from nitrification basin to denitrification one. Most of organic material was removed in nitrification basin, wherease the only exact amount of organics required in denitrification process was removed in denitrification one. This experiment resulted in that heterotrophic bacteria existing in aerobic basin governed the removal efficiency of organic compounds. In case the influent BOD concentration into nitrification basin was 80mg/l, it did not affect to accumulation of nitrifying bacteria, the balance of heterotrophic bacteria was proved to be an important factor in nitrification/denitrification method such as anaerobic and aerobic cycling type.

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Nitrification process analysis by respirometry in a sequencing batch reactor (호흡률을 이용한 연속회분식반응조의 질산화 공정 해석)

  • Kim, Donghan;Kim, Sunghong
    • Journal of Korean Society of Water and Wastewater
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    • v.33 no.1
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    • pp.55-62
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    • 2019
  • The respirometric technique has been used to analyze the nitrification process in a sequencing batch reactor(SBR) treating municipal wastewater. Especially the profile of the respiration rate very well expressed the reaction characteristics of nitrification. As the nitrification process required a significant amount of oxygen for nitrogen oxidation, the respiration rate due to nitrification was high. The maximum nitrification respiration rate, which was about $50mg\;O_2/L{\cdot}h$ under the period of sufficient nitrification, was related directly to the nitrification reaction rate and showed the nitrifiers activity. The growth rate of nitrifiers is the most critical parameter in the design of the biological nutrient removal systems. On the basis of nitrification kinetics, the maximum specific growth rate of nitrifiers in the SBR was estimated as $0.91d^{-1}$ at $20^{\circ}C$, and the active biomass of nitrifiers was calculated as 23 mg VSS/L and it was about 2% of total biomass.

Low Temperature Effects on the Nitrification in a Nitrogen Removal Fixed Biofilm Process Packed with SAC Media

  • Jang, Se-Yong;Byun, Im-Gyu
    • Journal of Environmental Science International
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    • v.22 no.1
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    • pp.1-6
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    • 2013
  • A fixed biofilm reactor system composed of anaerobic, anoxic(1), anoxic(2), aerobic(1) and aerobic(2) reactor was packed with synthetic activated ceramic (SAC) media and adopted to reduce the inhibition effect of low temperature on nitrification activities. The changes of nitrification activity at different wastewater temperature were investigated through the evaluation of temperature coefficient, volatile attached solid (VAS), specific nitrification rate and alkalinity consumption. Operating temperature was varied from 20 to $5^{\circ}C$. In this biofilm system, the specific nitrification rates of $15^{\circ}C$, $10^{\circ}C$ and $5^{\circ}C$ were 0.972, 0.859 and 0.613 when the specific nitrification rate of $20^{\circ}C$ was assumed to 1.00. Moreover the nitrification activity was also observed at $5^{\circ}C$ which is lower temperature than the critical temperature condition for the microorganism of activated sludge system. The specific amount of volatile attached solid (VAS) on media was maintained the range of 13.6-12.5 mg VAS/g media at $20{\sim}10^{\circ}C$. As the temperature was downed to $5^{\circ}C$, VAS was rapidly decreased to 10.9 mg VAS/g media and effluent suspended solids was increased from 3.2 mg/L to 12.0 mg/L due to the detachment of microorganism from SAC media. And alkalinity consumption was lower than theoretical value with 5.23 mg as $CaCO_3$/mg ${NH_4}^+$-N removal at $20^{\circ}C$. Temperature coefficient (${\Theta}$) of nitrification rate ($20^{\circ}C{\sim}5^{\circ}C$) was 1.033. Therefore, this fixed film nitrogen removal process showed superior stability for low temperature condition than conventional suspended growth process.

Salt Acclimation Behavior of the Nitrifier Consortium for the Nitrification of Saline Wastewater

  • Seo, Jae-Koan;Kim, Sung-Koo
    • 한국생물공학회:학술대회논문집
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    • pp.590-593
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    • 2001
  • The effect of salinity on the nitrification efficiency of the nitrifier consortium was evaluated for the nitrification of saline wastewater. The nitrifier consortium, which was the activated sludge acclimated with ammonium as the only energy source, was used as the nitrifier for the salt acclimation. Airlift reactors for the nitrification of ammonia with increasing concentration in saline synthetic wastewater (35 g/I NaCD, and synthetic wastewater without salt as a control, were continuously operated with the nitrifier consortium for 43 days. The ammonia removal rate was about 23g ammonia-N/$m^3$/day in both the absence and presence of the salt. An accumulation of nitrite was observed in the saline nitrification reactor at an early period. However, the nitrite decreased to less than 1 mg/l after 39 days of operation. The salinity increased the acclimation time of the nitrifier consortium to obtain a stable marine nitrification system. However, the salt acclimated system showed the efficient removal of ammonia which was same as that without salt.

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Analysis and improvement measures of nitrification using industrial wastewater with high Nikel concentration (고농도 니켈을 함유한 산업하수의 질산화율 분석 및 개선 방안)

  • Im, Jiyeol;Gil, Kyungik
    • Journal of Wetlands Research
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    • v.19 no.4
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    • pp.501-507
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    • 2017
  • The heavy metal such as Nikel (Ni) in industrial wastewater is one of the major reasons of decreasing nitrification efficiency in municipal wastewater treatment plants (MWTPs). In this study, laboratory scale reactors were operated in order to analyse of nitrification efficiency and improvement measures. As a result, nitrification efficiency during high Ni concentration (0.295 mg/L) was about 20%. However nitrification efficiency during low Ni concentration (0.114 mg/L) was over 70%. The changes of the micro-organism activity according to Ni concentration was investigated as being the major reason behind the gap of nitrification efficiency through analysing AUR and SNR. Increasing the HRT in high Ni concentration also increased the nitrification efficiency. Thus, maintenance of microorganisms and increasing the HRT in nitrification reactors suggests that measures taken to treat wastewater is positively correlated with high concentration of heavy metal.

Nitrifying-genes Dynamics in the Enriched Bacterial Consortium Inoculated with Humic Soil (부식토 유래 질산화세균 consortium의 질산화 유전자 거동 특성)

  • Seo, Yoon-Joo;Lee, Yun-Yeong;Choi, Hyung-Joo;Cho, Kyung-Suk
    • Microbiology and Biotechnology Letters
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    • v.47 no.2
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    • pp.296-302
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    • 2019
  • In this study, the effects of ammonium concentration ($117.5-1155.0mg-N{\cdot}l^{-1}$), nitrite concentration ($0-50.0mg-N{\cdot}l^{-1}$), and temperature ($15-35^{\circ}C$) on nitrification performance and its functional genes (amoA-arc, amoA-bac, hao) in an enriched consortium inoculated with humic acid were determined. Notably, the maximum nitrification rate value was observed at $315mg-N{\cdot}l^{-1}$ of ammonium, but the highest functional gene copy numbers were obtained at $630mg-N{\cdot}l^{-1}$ of ammonium. No inhibition of the nitrification rate and functional gene copy numbers was observed via the added nitrites. The optimum temperature for maximum nitrification performance was observed to be $30^{\circ}C$. The amoA-bac copy numbers were also greater than those of amoA-arc under all test conditions. Notably, amoA-arc copy numbers and nitrification efficiency showed a positive relationship in network analysis. These results indicate that ammonium-oxidizing archaea and bacteria play important roles in the nitrification process.

Nitrogen Mineralization and Nitrification in a Mature Quercus acutissima Stand in Kwangnung, Kyonggi Province (경기도(京畿道) 광릉(光陵) 상수리나무 성숙림(成熟林)의 질소(窒素) 무기화(無機化)에 관(關)한 연구(硏究))

  • Kim, Choonsig
    • Journal of Korean Society of Forest Science
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    • v.87 no.1
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    • pp.20-26
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    • 1998
  • The objective of this study was to determine the rate of nitrogen mineralization and nitrification in a mature sawtooth oak(Quercus acutissima $C_{ARRUTH}$) stand in the Chungbu Forest Experiment Station, Kyonggi Province. Nitrogen mineralization and nitrification in the top 15cm of mineral soil were examined from November 1995 to November 1996 using an in situ buried bag method. Net nitrogen mineralization was 95.2mg/kg/yr and nitrification was 65.4mg/kg/yr. Nitrification consisted of 69% of annual nitrogen mineralization. Neither nitrogen mineralization nor nitrification was significantly correlated with the monthly soil temperature and soil moisture content.

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Microbial Activity of Ammonia Oxidizing Bacteria and Ammonia Oxidizing Archaea in the Rice Paddy Soil in Wang-gung Area of Iksan, Korea (익산 왕궁지역 논 토양에서의 질산화 세균과 질산화 고세균의 미생물학적 작용)

  • Kim, Hyun-su
    • Journal of Soil and Groundwater Environment
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    • v.21 no.4
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    • pp.50-59
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    • 2016
  • Spatial and temporal changes in nitrification activities and distribution of microbial population of ammonia oxidizing bacteria (AOB) and ammonia oxidizing archaea (AOA) in paddy soils were investigated. Soil samples were collected in March and October 2015 from rice paddy with and without the presence of confined animal feeding operations. Incubation experiments and quantitative polymerase chain reaction showed that AOA's contribution to nitrification kinetics was much higher in locations where organic nitrogen in animal waste is expected to significantly contribute to overall nitrogen budget, and temporal variations in nitrification kinetics were much smaller for AOA than AOB. These differences were interpreted to indicate that different microbial responses of two microbial populations to the types and concentrations of nitrogen substrates were the main determining factors of nitrification processes in the paddy soils. The copy numbers of ammonium monooxygenase gene showed that AOA colonized the paddy soils in higher numbers than AOB with stable distribution while AOB showed variation especially in March. Although small in numbers, AOB population turned out to exert more influence on nitrification potential than AOA, which was attributed to higher fluctuation in AOB cell numbers and nitrification reaction rate per cells.

A Study on Nitrification of Saline Wastewater in Biofilter Process (생물막 공정에서 염분함유 폐수의 질산화에 관한 연구)

  • Choi, Dong Hyuk;Kim, Ki-Yong;Kwon, Joong-Chun;Kim, Tae-dong
    • Journal of the Korean Society of Urban Environment
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    • v.17 no.4
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    • pp.445-451
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    • 2017
  • Biologically advanced treatment process is widely used for high concentration wastewater treatment, and it has a considerable effect on the removal of nutrients flowing into the water environment. However, the research for food wastewater, fish processing wastewater, landfill leachate and the like, their high salinity adversely affecting the biological treatment efficiency, has rarely been conducted. This study investigated the influence of salinity on the nitrification of wastewater carrying high organic concentration using the Biofilter Process. Nitrification was not affected with low salinity concentration of $2,000{\sim}55,000mg{\cdot}NaCl/L$, however, it was affected with salinity concentration of $80,000mg{\cdot}NaCl/L$, resulting the reduction of nitrification rate to 11.4%. The initial neutral pH of the wastewater, including NaCl 30,000 mg/L and TN 500 mg/L, dropped to 6 or less as nitrification went along and reduced to 50%. In the case of basic region, the pH of the reactor was maintained at about 7.0 despite the nitrification reaction and the nitrification rate was about 80% or more. In the acidic region, the pH of the reactor was greatly decreased and nitrification was hardly achieved. As the pH level during the operation period was adjusted to the neutral region, the nitrification efficiency was higher than 99%. It could be postulated that for the effective nitrification, the pH of influent water needed to be adjusted to neutral or higher and maintained during nitrification process.

Improvement of Nitrification Efficiency by Activated Nitrifying Bacteria Injection at Low Temperature (활성화된 질산화균 주입에 의한 저온 질산화효율 향상)

  • Lim, Dongil;Kim, Younghee
    • Journal of the Korean Society of Urban Environment
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    • v.18 no.4
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    • pp.473-483
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    • 2018
  • In this study, we have developed a lab scale bioreactor to identify the characteristics of nitrification reaction according to operation condition (temperature, inhibitor (as Cl), activated nitrifying bacteria (ANB). etc) to improve nitrification efficiency at low temperature. Recovery rate of nitrification took about 4 days to reach the normal level by injected ANB after inhibition shock of CI injection at $20^{\circ}C$, when measured the concentration of $NO_2{^-}-N+NO_3{^-}-N$ in the effluent. In the case of $10^{\circ}C$, recovery of nitrification rate took about 4 days to reach the level of half to the normal level and 7 days for complete recovery which took 3 days more than those at $20^{\circ}C$. At $10^{\circ}C$ considering the winter season, the specific nitrification rate(SNR) of the from 1 day to 6 days after injected ANB according to its operation condition increased from 0.029 to 0.767 mgN/gSS/hr. The simulated SNR for the 8th day after the injected ANB at $10^{\circ}C$ was 0.840, 3.625 mgN/gSS/hr, respectively as linear function and exponential function, expecting to exceed level of 2.592 mgN/gSS/hr at normal condition. It was confirmed that injection of ANB during low temperature operation has many effects for improving nitrification efficiency through this study. In future studies, if further studies are carried out the determination of ANB injection and the design of efficient ANB reactor considering the changes of operating characteristics by site, it will contribute to the improvement of nitrification efficiency in winter season.