• 상하수도학회지
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• 제25권4호
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• pp.503-510
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• 2011

Ammonia in water which is toxic to human, its concentration is regulated below 0.5 mg/L in drinking water. Current study aimed to develop appropriate models for ammonia stripping using hollow fiber membrane contactor. Two different models were developed during the study. Model 1 was assumed only free ammonia ($NH_3$) transfer in stripping process, whereas the Model 2 was assumed with total ammonia ($NH_3+{NH_4}^+$) transfer. Ammonium chloride ($NH_4CI$), sodium hydroxide(NaOH) were used to make ammonia solution, which was concentration of 25 mg as N/L at a pH of 10.5. The experimental conditions were such that, the liquid flow was in tube-side in upward direction and t he gas flow was on shell-side in downward direction a t room temperature. The experimental and modeling results showed that marginal difference were observed at low gas flux. However the difference between the both models and experimental value were increased when the gas flux was increased. The study concludes that the Model 1 with free ammonia is more appropriate when both models were compared and useful in ammonia stripping process at low gas flux.

• 대한수의학회지
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• 제30권1호
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• pp.103-106
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• 1990

Effects of ammonia water on the spornlation of coccidial oocysts collected from bovine feces were studied with particular reference to the various levels of ammonia water (1% to 10%) for 30 minute conservation at room temperature. The sporulation rates showed a negative linear coorelation according to the treatment leavels of ammonia water, 85.3% at 1% level to 8.9% at 10% level. The optimum level of ammonia concentration was regarded as 5% to 10% with more than 80% of sporulation inhibition effect.

• 상하수도학회지
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• 제9권4호
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• pp.107-114
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• 1995

The raw drinking water quality is getting worse because of the winter drought and the conventional treatment system is'nt suitable to obtain the satisfied quality of water. So, the advanced water system, BAC(Biological Activated Carbon) process is said to be effective to remove dissolved organics and ammonia nitrogen. In our study, the BAC pilot plant using Nak-dong river water is tested in low temperature. Following results are found from the study. The ammonia nitrogen removal rate of BAC system using wood-based carbon (PICABIOL) was 99% in $6^{\circ}C$ temperature. Chlorine dosage in wood-based BAC effluent was reduced to 67% of that in sand filtered wate. It resulted from the removal of ammonia nitrogen. Also, THM formed by chlorine addition in wood-based BAC effluent was decreased to 65% of that in sand filtered water. In the case of dual-filter, the removal efficiency of ammonia nitrogen was increased 30% more than in conventional sand filter. According to this result, the ammonia nitrogen load to BAC system could be lessened by the use of dual-filter.

• 한국수소및신에너지학회논문집
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• 제30권6호
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• pp.621-628
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• 2019

The use of the ammonia-water zeotropic mixture as a working fluid in the power generating system has been considered as a proven technology for efficient recovery of low-grade heat sources. This paper presents a thermodynamic performance analysis for ammonia-water evaporator using low-grade heat source, based on the exergy and entransy which has been recently introduced as a physical quantity to describe the heat transfer ability of an object. In the analysis, effects of the ammonia mass fraction and source temperature of the binary mixture are investigated on the system performance such as heat transfer, effectiveness, exergy destruction, entransy dissipation, and entransy dissipation based thermal resistance. The results show that the ammonia mass concentration and the source temperature have significant effects on the thermodynamic system performance of the ammonia-water evaporator.

• 유기물자원화
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• 제27권3호
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• pp.75-80
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• 2019

본 연구는 난류로 흐르는 물에서 미세먼지 전구체 중 하나인 암모니아가 흡수되는 거동을 해석하였다. 물의 흐름이 층류보다 난류인 조건에서 암모니아의 침투 깊이가 더 깊으므로 레이놀즈 수가 $10^4$보다 큰 난류 조건이 고려된다. 거동 해석을 위하여, 무차원 물질전달 지배방정식과 상온 기준의 일정한 물성치들이 사용되었다. 물에서의 암모니아 확산계수와 물의 동점도계수는 각각 $2.45{\times}10^{-9}m^2/s$와 $1{\times}10^{-6}m^2/s$이었다. 물에서의 암모니아 농도 분포는 암모니아에 노출되기 시작하는 지점으로부터의 위치에 대하여 산출되었다. 혼합 깊이에 따른 정량적인 분포 또한 도출되었다. 이와 같은 정량적인 해석은 난류로 흐르는 물이 층류로 흐르는 것과 비교하여 얼마나 더욱 효율적으로 암모니아를 제거할 수 있는지에 대한 통찰력을 제시할 수 있다.

• 상하수도학회지
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• 제10권1호
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• pp.78-84
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• 1996

The presence of ammonia, usually in the form of ammonium ion ($NH_4{^+}$), can enhance bacterial growth m the distribution system and make the production of drinking water more costly if ammonium must be removed to ensure good disinfection. Removal of ammonia by biological oxidation could be economical which prevents excess chlorine dosage In this research, effects of hydraulic retention time (HRT) and media type on the ammonia removal efficiencies of submerged biofilm reactor were investigated. The biofilm reactors combined the characteristics of high biological solids capture efficiency and good hydraulic control. The results indicate that biofilms can remove over 77 percent of the ammonia with HRT of longer than 2 hr even at low temperature ranging from 14.6 to $16.6^{\circ}C$. The HRT has a significant effect on nitrification. The overall nitrification and efficiency of ammonia removal increase with increasing HRT. It has also been observed that when the fibrous media was used, the ammonia removal, nitrification rate and endurance to shock improved.

• 유기물자원화
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• 제28권4호
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• pp.35-41
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• 2020

본 연구는 수로 표면에 고정된 히드록실아민-산화환원효소가 암모니아 흡수에 미치는 영향에 대하여 해석하였다. 이 효소에 의한 반응은 히드록실아민을 아질산으로 변화시키는 것으로서 신속하게 진행된다. 영향의 해석을 위하여, 무차원 물질전달 지배방정식이 수립되었고 상온 기준의 일정한 물성치들이 사용되었다. 물에서의 암모니아 확산계수와 물의 동점도계수는 각각 2.45×10-9 ㎡/s와 1×10-6 ㎡/s이었다. 물에서의 암모니아 농도 분포는 암모니아에 노출되기 시작하는 지점으로부터의 위치에 대하여 산출되었다. 혼합 깊이에 따른 정량적인 분포 또한 도출되었다. 이와 같은 정량적인 해석은 수로 표면에 고정화된 효소가 암모니아 제거에 효율적으로 이용될 수 있는지에 대한 통찰력을 제시할 수 있다.

• 한국수산과학회지
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• 제42권4호
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• pp.373-379
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• 2009

This study investigated oxygen consumption rate (OCR), $Q_{10}$ coefficient and ammonia excretion rate of the greenling, Hexagrammos otakii Jordan et Starks with the average body weight of 250 g in a semi-recirculated respiratory measuring system. The experiment was done under three different water temperatures (10, 15, $20^{\circ}C$) and five different ambient ammonia concentrations (0, 2.5, 5, 10, 20 mg/L). As the water temperature and ambient ammonia concentration increased the OCR has significantly increased (P<0.05). Given experimental conditions, the OCR of greenling were $50.8{\sim}159.4\;mg\;O_2\;kg^{-1}\;hr^{-1}$ and the relationship of water temperature (T) and ambient ammonia concentration (C) on the OCR were following: OCR = 41.3 - 1.87T - 7.38C + $0.463T^2$ + $0.66lC^2$ + 0.642TC - $0.011T^3$ - $0.010C^2$ - $0.031TC^2$ - $0.001T^2$C ($r^2$= 0.9226). $Q_{10}$ coefficients were $1.88{\sim}3.50$ for $10^{\circ}C$ to $15^{\circ}C$, $1.03{\sim}2.73$ for $15^{\circ}C$ to $20^{\circ}C$ and $1.40{\sim}1.90$ for $10^{\circ}C$ to $20^{\circ}C$, respectively. In general, the ammonia excretion rate tended to increase with increasing of the water temperature within normal ambient ammonia concentration. However, interestingly, it was observed that ammonia was absorbed rather than excreted above the ambient ammonia concentration of $2.5\;mg\;L^{-1}$, regardless of the water temperature. Thus, the largest ammonia absorption rate (AAR) was obserbed at the level of $98.4\;mg\;TAN\;kg^{-1}\;hr^{-1}$. The relationship ambient ammonia concentration (C) on AAR was following: Y = 1.61 + $10.9X^{0.7}$ ($r^2$ = 0.889).

• 대한환경공학회지
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• 제22권11호
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• pp.1969-1976
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• 2000

폐수의 복합독성과 다수의 미지 화합물의 영향을 평가하는 것은 많은 시간이 요구되고 분석상 어려움이 존재하는 경우가 많다. 그러므로 폐수중 독성을 나타내는 원인물질의 탐색과 처리효과를 평가하기 위한 방법을 확립하는 것이 절실히 요구된다. 본 연구에서는 질산화 저해제를 이용하여 혼합미생물중 질산화 미생물과 종속영양미생물을 구분하여 암모니아 저해도 실험을 수행하였으며, 이때 저해도는 dehydrogenase activity(DHA)를 이용한 미생물활성도의 차이로서 평가하였다. DHA에 의한 암모니아 저해 연구는 총 암모니아의 영향, 유리 암모니아의 영향, 질산화 미생물과 종속영양미생물의 암모니아 저해도에 대해 각각 평가되었다. 암모니아 독성은 총 암모니아 농도와 pH가 증가할수록 크게 나타나 유리 암모니아의 역할이 중요하게 작용함이 밝혀졌으나 미생물의 DHA는 총 암모니아와 유리 암모니아가 함께 고려되어야 정확히 평가될 수 있었다. 3.000mg/L 이상의 고농도의 암모니아에서는 질산화 미생물이 종속영양미생물 보다 심한 저해를 받는 것으로 나타났다.

• 한국수소및신에너지학회논문집
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• 제23권1호
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• pp.65-72
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• 2012

Rankine cycle using ammonia-water mixture as a working fluid has attracted much attention, since it may be a very useful device to extract power from low-temperature heat source. In this work, the thermodynamic performance of regenerative ammonia-water Rankine cycle is thoroughly investigated based on the second law of thermodynamics and exergy analysis, when the energy source is low-temperature heat source in the form of sensible energy. In analyzing the power cycle, several key system parameters such as ammonia mass concentration in the mixture and turbine inlet pressure are studied to examine their effects on the system performance including exergy destructions or anergies of system components, efficiencies based on the first and second laws of thermodynamics. The results show that as the ammonia concentration increases, exergy exhaust increases but exergy destruction at the heat exchanger increases. The second-law efficiency has an optimum value with respect to the ammonia concentration.