• 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.

• 한국수소및신에너지학회논문집
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• 제22권1호
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• pp.109-117
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• 2011

Since the thermal performance of cycles for use of low-temperature source is low if a pure working fluid is used, the cycles using ammonia-water binary mixture as a working fluid has attracted much attention over past two decades. Recently, several commercial power plants using Kalina cycles have been built and being operated successfully. In this work thermodynamic performance of Kalina cycles using ammonia-water mixture as a working fluid is investigated for the purpose of extracting maximum power from low-temperature energy source. Special attention is paid to the effect of system parameters such as concentration of ammonia and turbine inlet pressure on the characteristics of the system. Results show that the system performance is influenced sensitively by the ammonia concentration, and the role of the performance of heat exchangers is crucial.

• 설비공학논문집
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• 제12권1호
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• pp.102-111
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• 2000

A numerical model which simulates the simultaneous heat and mass transfer within a vertical tube GAX absorber was developed. The ammonia vapor and the solution liquid are in counter-current flow, and the hydronic fluid flows counter to the solution liquid. The film thickness and the velocity distribution of the liquid film were obtained by matching the shear stress at the liquid-vapor interface. Two-dimensional diffusion and energy equations were solved in the liquid film to give the temperature and concentration, and a modified Colburn-Drew analysis was used for the vapor phase to determine the heat and mass fluxes at the liquid-vapor interface. The model was applied to a GAX absorber to investigate the absorption rates, temperature and concentration profiles, and mass flow rates of liquid and vapor phases. It was shown that the mass flux of water was negligible compared with that of ammonia except the region near the liquid inlet. Ammonia absorption rate increases rapidly near the liquid inlet and decrease slowly. Both the absorption rate of ammonia vapor and the desorption rate of water near the liquid inlet increase as the vapor mass flow rate increases, but the mass fluxes of the ammonia and the water near the liquid outlet decrease as the mass flow rate of the vapor increases.

• Journal of information and communication convergence engineering
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• 제2권1호
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• pp.22-25
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• 2004

A highly sensitive ammonia gas sensor using thick-film technology has been fabricated and examined. The sensing material of the gas sensor is FeOx-$WO_{3}-SnO_{2}$ oxide semiconductor. The sensor exhibits resistance increase upon exposure to low concentration of ammonia gas. The resistance of the sensor is decreased, on the other hand, for exposure to reducing gases such as ethyl alcohol, methane, propane and carbon monoxide. A novel method for detecting ammonia gas quite selectively utilizing a sensor array consisting of an ammonia gas sensor and a compensation element has been proposed and developed. The compensation element is a Pt-doped $WO_{3}-SnO_{2}$gas sensor which shows opposite direction of resistance change in comparison with the ammonia gas sensor upon exposure to ammonia gas. Excellent selectivity has been achieved using the sensor array having two sensing elements.

• 청정기술
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• 제27권2호
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• pp.168-173
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• 2021

도금폐수의 처리는 폐수의 pH, 중금속 및 시안(CN)함유에 따라 다양하고 복잡한 공정이 적용된다. 이중 시안(CN)의 처리는 차아염소산(NaOCl)을 이용한 알칼리 염소 처리법이 일반적으로 많이 사용되고 있다. 그러나, 암모니아성 질소(NH₃-N)와 시안(CN)이 동시에 함유될 경우 암모니아성 질소(NH₃-N)의 처리를 위해 차아염소산(NaOCl) 이 과다하게 소비되는 문제가 있다. 이러한 문제를 해결하기 위하여 본 연구는 시안(CN)처리에 있어서 1) 알칼리염소법에서 암모니아성 질소(NH₃-N)농도에 따른 차아염소산(NaOCl)의 소모량을 조사하고 2) ferrate (VI)가 시안(CN)을 선택적으로 처리할 수 있는지를 평가하였다. 모의폐수를 이용한 실험결과 알칼리염소법에서는 암모니아성 질소(NH₃-N)농도가 높을수록 시안(CN)의 제거율이 감소하였으며 차아염소산(NaOCl)의 소비량이 암모니아성 질소(NH₃-N) 농도에 따라 선형적으로 증가하였다. Ferrate (VI)를 이용한 시안(CN) 제거에서는 암모니아성 질소(NH₃-N) 농도에 관계없이 시안(CN)의 제거를 확인하였으며 이때 암모니아성 질소(NH₃-N)의 제거율은 낮아 ferrate (VI)가 시안(CN)을 선택적으로 제거함을 확인하였다. Ferrate (VI)의 시안(CN) 제거효율은 pH가 낮을수록 높게 나타났고 ferrate (VI) 주입량에 관계없이 99% 이상을 보였다. 실제 도금폐수에 적용한 결과에서는 ferrate (VI)와 시안(CN)의 투입 몰비 1:1에서 99% 이상의 높은 제거율을 보였으며 이는 화학양론 반응식의 몰비와 일치하는 결과로 모의 폐수와 동일하게 암모니아성 질소(NH₃-N) 및 기타오염물질이 함유된 실제 폐수에서도 선택적으로 시안(CN)을 제거하는 것으로 확인되었다.

• 대한화학회지
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• 제13권2호
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• pp.171-175
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• 1969

This study wa attempted to extract the Potash-Ammonia Fertilyzer in most satisfactory yield from the Uncalcinecl Domestic Alunite ore applying an optimal reaction conditions (Ammonia water concentration and applicable reaction pressure, etc.), it was found that almost all amount of $K_2SO_4$ was extracted in the forms of $K_2SO_4·(NH_4)_2SO_4$mixture under such conditions. The experimental data to note are as follows: 1. The optimal pressure applied to the reaction was 600 to 700 Psig. 2. The optimal concentration of Ammonia water was 7 Mol/L. 3. The reaction time needed was 3 hours. 4. The extraction rate and degree were not at variance with sorts and occurrences of Alunite ore.

• 한국환경농학회지
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• 제25권3호
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• pp.195-201
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• 2006

The operational characteristics of anaerobic bioreactors in treating swine wastewater were evaluated upto hydraulic retention time (HRT) of 1 day and organic loading rate (OLR) of $5.1kg-COD/m^3{\cdot}d$ for 200 days. The bioreactors were effective in treating swine wastewaters with COD removal efficiency of $78.9{\sim}81.5%$ and biogas generation of $0.39{\sim}0.59m^3/kg-COD_r$ at OLR of $1.1{\sim}2.2kg-COD/m^3{\cdot}d$. The two-stage ASBF anaerobic bioreactors was effective in treating different characteristics of swine wastewaters since they showed high and stable COD removal efficiency at high OLR due to effective retention of biomass by media and staging. The effects of ammonia on anaerobic digestion were investigated by operating two-stage ASBF reactors using swine wastewaters as influent without and with ammonia removal at HRT of $1{\sim}2$ days and OLR of $2.2{\sim}9.6kg-COD/m^3{\cdot}d$ for 250 days. The COD removal efficiency and biogas generation of two-stage ASBF reactors was decreased by increasing influent ammonia concentrations to 1,580 mg (T-N)/L with increasing OLR to $6.3kg-COD/m^3{\cdot}d$, while those were increased by maintaining influent ammonia concentrations below 340 mg (T-N)/L by MAP precipitation with increasing OLR to $9.6kg-COD/m^3{\cdot}d$. Initial inhibition of ammonia on anaerobic processes was observed at a concentration of 760 mg (T-N)/L and the COD removal efficiency and biogas generation dropped to 1/2 at ammonia concentration ranges of $1,540{\sim}1,870mg$ (T-N)/L. It is essential to remove ammonia in swine wastewaters to an initial inhibition level before anaerobic processes for the effective removal of COD.

• Environmental Engineering Research
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• 제13권3호
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• pp.119-124
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• 2008

Ammonia is an inorganic compound that may cause severe odor problem. In this study the effectiveness of applying natural neutralizer to destroy and remove the odor-causing compound from gas streams was studied. Experimental result evaluated with a bench-scale apparatus via the neutralization of gas phase. This indicates that the natural neutralization depends on the gas concentration, gas residence time, temperature and pH. Removal efficiency of ammonia from gas stream was achieved by 95% using theconvection in the packed bed. This study proved the chemical neutralization technology was effective for controlling inorganic odor-causing compound.

• Journal of Microbiology and Biotechnology
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• 제4권3호
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• pp.191-194
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• 1994

Acetoin and ammonia, the precursors of tetramethylpyrazine (TMP) having "nutty " or "roasted" flavors, were produced by cultivating Lactococcus lactis ssp. lactis biovar. diacetilactis FC1. The effects of the volume concentration ratio (VCR) of cell-free medium on the formation of TMP were investigated using a rotary evaporator at $70^{\circ}C than at 80^{\circ}C$. As the VCR increased, the formation of TMP and the conversion ratio of acetoin to TMP increased. More TMP were formed at $70^{\circ}C than at 80^{\circ}C$. As the VCR increased, the concentration of acetoin decreased implying the formation of TMP from acetoin and ammonia.

• 설비공학논문집
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• 제14권10호
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• pp.844-853
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• 2002

A dynamic model which simulates the coupled heat and mass transfer within a vertical tube absorber was developed. The liquid film is a binary mixture of two components, and both of these components are present in the vapor phase. The pressure, concentration, temperature and mass flow rate of the vapor are obtained by assuming that the pressure is uniform within an absorber. The model was applied to an absorber for an ammonia/water absorption refrigerator. The transient behaviors of the pressure, the outlet temperature and the concentration of the solution and the cooling water outlet temperature on a step change at the absorber inlet of the cooling water temperature, the vapor mass flow rate and the concentration of the solution were shown.