• 미생물학회지
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• 제21권2호
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• pp.79-85
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• 1983

Ammonia oxidation activity of polluted water samples in Jinhae Bay and isolated strain from the seawater was investigated, and effects of environmental factors such as temperature, salinity, substrate concentration to the ammonia oxidation were also investigated. The ammonia oxidation activities of sediments, 0.01-0.04mg eq. $NO_2-N/l/h$, were exceptionally higher than that of sea water, $0.5{\sim}1{\mu}g$ eq. $NO_2-N/l/h$. the activities of muddy sediments at station 4 and 2 were 0.03~0.04mg eq. $NO_2-N/l/h$ and that of sandy sediment at station 3 was 0.002mg eq. $NO_2-N/l/h$. In the case of sea water, the activity of polluted area, station 1, was 2 times higher than that of offshore, station 4. The isolated strain reached log phase after 30days culturs and its oxidation activity was $2{\sim}3{\mu}g$ eq. $NO_2-N/day$. The maximum oxidation of ammonia by IA 13 strain occured at 30mg/l oxidation increased with the salinity rising up to 100% seawater concentraion. And temperature for maximum oxidation of ammonia was $35^{\circ}C$. the oxidation increased with the salinity rising up to 100% seawater concentration.

• Journal of Microbiology and Biotechnology
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• 제23권5호
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• pp.719-723
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• 2013

Nitrification in wastewater treatment emits a significant amount of nitrous oxide ($N_2O$), which is one of the major greenhouse gases. However, the actual mechanism or metabolic pathway is still largely unknown. Selective nitrification inhibitors were used to determine the nitrification steps responsible for $N_2O$ emission with activated sludge and enriched nitrifiers. Allylthiourea (86 ${\mu}M$) completely inhibited ammonia oxidation and $N_2O$ emission both in activated sludge and enriched nitrifiers. Sodium azide (24 ${\mu}M$) selectively inhibited nitrite oxidation and it led to more $N_2O$ emission than the control experiment both in activated sludge and enriched nitrifiers. The inhibition tests showed that $N_2O$ emission was mainly related to the activity of ammonia oxidizers in aerobic condition, and the inhibition of ammonia monooxygenase completely blocked $N_2O$ emission. On the other hand, $N_2O$ emission increased significantly as the nitrogen flux from nitrite to nitrate was blocked by the selective inhibition of nitrite oxidation.

• 한국수소및신에너지학회논문집
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• 제33권6호
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• pp.786-794
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• 2022

Green ammonia is a promising renewable energy carrier. Green ammonia can be used in various energy conversion devices (e.g., engine, fuel cell, etc.). Ammonia has to be fed with hydrogen for start-up and failure protection of some energy conversion devices. Ammonia can be converted into hydrogen by decomposition and partial oxidation. Especially, partial oxidation has the advantages of fast start-up, thermally self-sustaining operation and compact size. In this paper, thermodynamics, start-up and operation characteristics of ammonia partial oxidation were investigated. O₂/NH₃ ratio, ammonia flow rate and catalyst volume were varied as operation parameters. In thermodynamic analysis, ammonia conversion was maximized in the O₂/NH₃ range from 0.10 to 0.15. Ammonia partial oxidation reactor was successfully started using 12 V glow plug. At 0.13 of O₂/HN₃ ratio and 10 LPM of ammonia flow rate, ammonia partial oxidation reactor showed 90% of ammonia conversion over commercial Ru catalyst. In addition, Increasing O₂/NH₃ ratio from 0.10 to 0.13 was more effective for high ammonia conversion than increasing catalyst volume at 0.10 of O₂/NH₃.

• 대한환경공학회지
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• 제22권1호
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• pp.103-111
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• 2000

양어용수 재순환을 위한 생물여과상의 처리효율을 향상시키기 위하여 전처리로서 오존처리와 고급산화($H_2O_2/O_3$) 처리가 다양한 조건하에서 시도되었다. 오존처리시 암모니아는 일차속도반응식으로 제거되었으며, 중탄산염 알칼리도가 증가할수록 제거효율이 향상되어 200 mg/L as $CaCO_3$에서 약 46%가 제거되었다. 고급산화법($H_2O_2/O_3$)을 적용시 알칼리도를 포함한 폐수의 경우 중탄산염의 저해작용으로 암모니아 제거율이 저조하였으나 0.1 N KOH로 초기 pH를 약 8.2로 맞추어 실험한 결과 암모니아 제거율이 오존처리시보다 향상되었다. 특히, $H_2O_2/O_3=0.25$ 조건하에서 가장 높은 암모니아 제거율을 나타내었으며, pH가 9 이상일 때 반응시간 30분동안 약 90%의 암모니아가 제거되었다. 그러나 유기물과 암모니아가 공존시 오존처리와 고급산화처리 모두 유기물과 산화제와의 빠른 반응으로 인하여 암모니아 제거율이 크게 저하되었으며, 최적 $H_2O_2/O_3$ 비도 변하였다. 암모니아 제거와 마찬가지로 고급산화처리의 경우 입자성유기물의 빠른 분해로 인하여 초기 10분간 DOC(dissolved organic carbon)농도가 증가한 후 서서히 감소하였다. 초기 암모니아 농도를 2배 이상 증가시켜도 유기물 산화에 저해를 주지 못하였다.

• 한국물환경학회지
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• 제21권5호
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• pp.505-510
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• 2005

The objective of this study was to remove non-biodegradable matters and ammonia ion in livestock wastewater using Fenton oxidation and Zeolite adsorption process. After coagulation process as 1st treatment, non-biodegradable matters remained after 1st treatment were removed by using OH radical produced in Fenton oxidation process. Zeolite as cation adsoption process was used to remove ammonia ion in 2nd treatment water. As a result of treatment using these processes, NBDCOD removal efficiency was over 90% and ammonia ion was almost removed. Most aromatics or polynuclear aromatics like benzene, phenol and scatol in livestock wastewater wasn't detected after Fenton oxidation process.

• Environmental Engineering Research
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• 제21권2호
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• pp.140-144
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• 2016

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.

• 한국대기환경학회지
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• 제24권5호
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• pp.512-522
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• 2008

Ammonia is a major compound of odor in livestock house. To enhance the performance of ammonia oxidation (decomposition). the gas-liquid, two phase photocatalytic oxidation system was designed and prepared in this study. Commercial P-25 as $TiO_2$ catalyst was used for ammonia decomposition. V/P-25 catalyst prepared by sol gel method was also used for the removal of by-producted $NO_x$ in $NH_3$ oxidation reaction. When $TiO_2$ was used as a photocatalyst, the conversion to $N_2$ in ammonia decomposition reached above 90% until 200hr (The air flow rate of 4L/min with the ammonia concentration up to 25ppm.). However, considerable amounts of NO and $NO_2$ were formed as a result of $NH_3$ oxidation (as a by-product). Therefore, we added Vanadia impregnated $TiO_2$(P-25) catalyst for the removal of $NO_x$ at the end of reaction trail. The results of a pilot-scale operation were successful to achieve the simultaneous removal of $NH_3\;and\;NO_x$ about 81 and 87%, respectively.

• 대한화학회지
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• 제10권2호
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• pp.76-90
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• 1966

Ammonium sulfate synthesized by the air oxidation methods without catalyst using the reaction vessel which was fitted with fritted glass at the bottom of it and introducing, through the bottom, ammonia and air with constant flow rates to sulfurous acid solution of constant concentrations at the given temperatures. The experiment showed that the oxidation process was accelerated in accord with the increase of the air flow rates when the ammonia flow rate was constantly kept at ca. 100ml/min. in high temperatures. When the pH of the solution reached 9.0, the oxidation was nearly completed. It is assumed that in the process of reaction, $[O_{2}{\to}HSO_{3}^-]^{\neq}$ would be produced as an activated complex and the reaction was thought to be first order. The experiment indicated that the 0.5M sulfurous solution could be oxidized up to 98.54% at the flow rates of ammonia and air, 100ml/min., and 4l/min., respectively at $50^{\circ}C$.

• 환경위생공학
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• 제19권1호
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• pp.1-7
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• 2004

This study was conducted to supply basic informations on development of water treatment process for the ozonation of ammonia depend on pH variation with or without bromide catalysis. The results were as follows: The oxidation rate of ammonia increased depend on pH increase at ozone/bromide process. It was found that overall kinetics was zero order with respect to reaction time and reaction velocity constant of zero order increased depend on pH increase from 4.9 to 9.5 and the equation of linearization was $k_{o}$ = 0.00565 ${\times}$ [pH] + 0.0069 at ozone/bromide process. The denitrification reaction of ammonia was superior as the pH increase in the presence of bromide.

• Membrane and Water Treatment
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• 제9권3호
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• pp.189-194
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• 2018

Electrochemical reduction of nitrate was studied using Zn, Cu and (Ir+Ru)-Ti cathodes and Pt/Ti anode in a cell divided by an ion exchange membrane. During electrolysis, effects of the different cathode types on operating parameters (i.e., voltage, temperature and pH), nitrate removal efficiency and by-products (i.e., nitrite and ammonia) formation were investigated. Ammonia oxidation rate in the presence of NaCl was also determined using the different ratios of hypochlorous acid to ammonia. The operating parameter values were similar for all types of cathode materials and were maintained relatively constant. Nitrate was well reduced and converted mostly to ammonia using Zn and Cu cathodes. Ammonia, produced as a by-product of nitrate reduction, was oxidized in the presence of NaCl in the electrochemical process and the oxidation performance was enhanced upon increasing the hypochlorous acid-to-ammonia ratio to 1.09:1. Zn and Cu cathodes promoted the nitrate reduction to ammonia and the produced ammonia was finally removed from solution by reacting with hypochlorite ions. Using Zn or Cu cathodes, instead of noble metal cathodes, in the electrochemical process can be an alternative technology for nitrate-containing wastewater treatment.