• 상하수도학회지
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• 제26권5호
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• pp.649-658
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• 2012

In this study, the influencing factors for efficient anaerobic digestion of high strength ammonia-nitrogen wastewater removal were investigated by testing biochemical methane potential test. In the influencing factors, the trace metals which could increase activity of anaerobic microorganisms, microbial concentration and types were evaluated. In the results, trace metals supplementation showed gas production amount higher than those without addition of trace metals. Among the tested trace metals, B, Ni, and Se were preferable to gas production. In the result of gas production according to the microbial concentration, the amount of gas production was proportional to the microbial concentration. In addition, the shortest lag time and the fastest gas production rate were achieved when the highest microbial concentration was tested. granule-type microorganism produced more gas than suspended-type microorganism. In conclusion, the efficient anaerobic digestion for high strength ammonia-nitrogen wastewater removal could be achieved by applying necessary trace metals injection and high concentration granule type microorganism.

• Bulletin of the Korean Chemical Society
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• 제30권9호
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• pp.2032-2038
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• 2009

The amount of phenol and NaOH for the colorimetric determination of ammonia in Korean standard methods (KSM) is found to be highly excessive compared to the standard methods of several other countries. The absorbance of indophenol formed by the Berthelot reaction for ammonia analysis was measured under the various reaction conditions classified in experiment groups 1, 2, 3, 4 and KSM and American standards methods (ASM), and the relationships between the absorbance of indophenol and concentration of ammonia were compared. The amount of phenol can be reduced to 10 g (current 25 g in KSM) and NaOH can be reduced to 1.76 g (current 11 g in KSM) for the preparation of 200 mL phenate solution, and the absorbance sensitivity increased. The concentration of the phenol and NaOH correlatively affect the pH of the solution, which is a critical variable in achieving the maximum sensitivity and rapid and stable color development.

• 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.

• 열처리공학회지
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• 제32권5호
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• pp.201-211
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• 2019

Low carbon steel (S20C steel) and SPCC steel sheet have been austenitic nitrided at $700^{\circ}C$ in a closed pit type furnace by changing the flow rate of ammonia gas and heat treating time. When the flow rate of ammonia gas was low, the concentration of residual ammonia appeared low and the hardness value of transformed surface layer was high. The depth of the surface layer, however, was shallow. With increasing the concentration of residual ammonia by raising up the ammonia gas flow, both the depth of the surface layer and the pore depth increased, while the maximum hardness of the surface layer decreased. By introducing a large amount of ammonia gas in a short time, a deep surface layer with minimal pores on the outermost surface was obtained. In this experiment, while maintaining 10~12% of residual ammonia, the flow rate of inlet ammonia gas, 7 liter/min, was introduced at $700^{\circ}C$ for 1 hour. In this condition, the thickness of the surface layer without pores appeared about $60{\mu}m$ in S20C steel and $30{\mu}m$ in SPCC steel plate. Injecting additional methane gas (carburizing gas) to this condition played a deteriorating effect due to promoting the formation of vertical pores in the surface layer. For $1^{st}$ transformed surface layer for S20C steel, maintaining 10~12% residual ammonia condition via austenitic nitriding process resulted in ${\varepsilon}$ phase with relatively high nitrogen concentration (just below 4.23 wt.%N) among the mixed phases of ${\varepsilon}+{\gamma}$. The ${\varepsilon}$ phase was formed a specific orientation perpendicular to the surface. For $2^{nd}$ transformed layer for S20C steel, ${\gamma}$ phase was rather dominant (just above 2.63 wt.%N). For SPCC steel sheet, there appeared three phases, ${\gamma}$, ${\alpha}(M)$ and weak ${\varepsilon}$ phase. The nitrogen concentration would be approximately 2.6 wt.% in these phases condition.

• 한국대기환경학회지
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• 제26권4호
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• pp.432-442
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• 2010

Ammonia is a very important constituent of the atmospheric environment because it is the most dominant gaseous alkaline species present in the atmosphere. Ammonia is known to affect ecosystems at relatively low concentration. Ammonia flux from livestock facilities can be regulated by a number of environmental factors (pH, ammonium ion, temperature, wind speed, etc). The increases in wind speed above manure from 0.0 m/s to 1.0 7m/s resulted in 2.5 times increases in ammonia flux. Wind speed and ammonia flux showed 0.982. A linear relationship with a correlation coefficient (r=0.982). When manure temperature increased from $3^{\circ}C$ to $36^{\circ}C$, the manure pH decreased approximately 0.30 to 0.46. As wind speed above the manure increased from 0.0 m/s to 1.07 m/s, ammonia flux increased approximately 2.5 times. The increasing manure temperature from $3^{\circ}C$ to $10^{\circ}C$, raised ammonia flux from 2.0 to 3.6 times (2.6 times in average similarly). The increases of manure temperature from $3^{\circ}C$ to $25^{\circ}C$ increased ammonia flux from 5.7 to 12.9 times (8.5 times in average). In this study, the correlation coefficient between ammonia flux and manure temperature was found from 0.972 to 0.989. Results of our research showed that ammonium ion concentration, pH of manure and wind speed were important factors in controlling the ammonia flux from manure livestock facilities.

• Journal of Electrochemical Science and Technology
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• 제13권1호
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• pp.63-70
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• 2022

Compared with hydrogen, ammonia has the advantages of high gravimetric hydrogen densities (17.8 wt.%), ease of storage and transportation as a chemical hydrogen storage medium, while its application in small-scale on-site hydrogen production scenarios is limited by the need for complex separation equipment during high purity hydrogen production. Therefore, the study of PEMFC, which can directly utilize ammonia decomposition gas, can greatly expand the application of fuel cells. In this paper, the output characteristics, fuel efficiency and the variation trend of hydrogen concentration and local current density in the anode channel of fuel cell with the output voltage of PEMFC fueled by ammonia decomposition gas were studied by experiment and simulation. The results indicate that the maximum output power of the hybrid fuel decreases by 9.6% compared with that of the pure hydrogen fuel at the same inlet hydrogen equivalent. When the molar concentration of hydrogen in the anode channel is less than 0.12, the output characteristics of PEMFC will be seriously affected. Employing ammonia decomposition gas as fuel, the efficiency corresponding to the maximum output power of PEMFC is approximately 47%, which is 10% lower than the maximum efficiency of pure hydrogen.

• 한국수산과학회지
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• 제47권6호
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• pp.840-846
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• 2014

This study investigated growth and hematological changes in parrotfish Oplegnathus fasciatus (~200 g/fish) reared under different total ammonia nitrogen (TAN) concentrations (0, 4, or 8 mg/L) for 6 weeks. Survival rates of parrotfish in all experimental groups did not significantly differ, as they were all ~100%. Although specific growth rate (SGR), weight gain, and daily feed intake in the high TAN concentration group (TAN8) were significantly lower than in the other two groups, there was no significant difference between the TAN4 group and the control group, (TAN0), indicating that parrotfish have a strong resistance to ammonia toxicity. As for temporal changes of the major blood components, cortisol increased as a result of stress caused by the high ammonia concentration in the TAN8 group. For this reason, the concentrations of energy sources such as glucose and total cholesterol were reduced. However, there was little difference among all experimental groups in concentrations of liver function glutamic oxaloacetic transaminase (GOT) and glutamic pyruvic transaminase (GPT), and nutrient factors, such as total protein and albumin.

• 한국수산과학회지
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• 제33권4호
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• pp.367-372
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• 2000

회전원판식 해수 여과시스템에서 암모니아성 질소 부하율과 수리학적 부하량이 암모니아 제거율에 미치는 영향을 조사하기 위하여 일련의 실험을 실시하였다. 이 실험에서 회전원판 시스템은 폴리비닐필름 원판으로 여과조를 제작하였는데, 여과조의 표면적은 $12m^2$으로 용적은 $0.075m^3$이다. 회전원판식 시스템에서 암모니아성 질소부하율에 따른 암모니아 제거율을 조사하기 위하여 암모니아원으로 염화암모늄을 $10{\~}150 g$ 첨가하였다. 회전원판식 순환여과 사육시스템의 사육수에 암모니아원으로 염화암모늄을 $10{\~}150 g$ 투입하여 사육수의 암모니아 농도 (x: NH_4-N mg/l)에 따라 회전원판 여과조에서의 암모니아 제거에 필요한 시간 (y: hr)을 조사하였으며, 그 관계식은 다음과 같았다. $y=3.51+7.76 lnx (r^2=0.936)$사육수의 암모니아 농도가 2mg/l일 때 회전원판 여과사육 시스템에서 암모니아 제거에 소요되는 시간은 10시간이었으나, 암모니아 농도가 5와 16.5mg/l에서는 각각 16과 27시간이 소요되었다. 따라서 사육수의 암모니아 농도가 높아질수록 암모니아 제거에 소요되는 시간이 감소하는 경향을 나타내었다. 결론적으로 회전원판 여과 사육시스템의 최대 암모니아 제거율은 사육수의 암모니아 농도가 16.5 mg/l까지 상승함에 따라 증가함을 알 수 있었다.

• Journal of Biosystems Engineering
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• 제28권3호
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• pp.225-230
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• 2003

This study was carried out to analyze the environmental variation of layer house at Iowa State in the USA. The analyzed seasons for this study were summer and winter. Analyzing factors are inside temperature and relative humidity, carbon dioxide concentration, ammonia concentration and emission. All factors were collected every 30 second from each house with portable monitoring units. In this study, two types of laying hen houses were monitored at the same season. One was a manure belt house, the other was a high-rise house. In order to estimate the ventilation rates of the laying hen houses, carbon dioxide concentration balance was used in this study. Ammonia concentrations and emission rates of the manure belt house are much lower than those of the high rise house. Daily mean ammonia concentrations in the manure belt house and high-rise house ranged from 3 to 7 ppm and 5 to 34 ppm, respectively. The daily ammonia emission rates averaged 0.68g/h$\cdot$500kg and 0.73g/h$\cdot$500kg for the manure belt house and 0.93g/h$\cdot$500kg and 2.89g/h$\cdot$500kg for the high-rise house in summertime and wintertime, respectively. Summertime is associated with much higher ammonia emission rates than wintertime because of much higher ventilation rates and ambient air temperature, even though the concentrations may be lower.

• 대한환경공학회지
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• 제22권1호
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• pp.53-60
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• 2000

본 연구는 활성탄 유동상 반응조의 암모니아 부하를 $0.1{\sim}7.5kg\;NH_3-N/m^3{\cdot}day$의 범위에서 단계적으로 증가시키면서 암모니아 부하가 질산화 효율 및 아질산성 질소의 축적에 미치는 영향을 파악하기 위하여 수행되었다. 실험 결과, $1.8kg\;NH_3-N/m^3{\cdot}day$ 이상의 암모니아 부하에서는 처리수의 아질산성 질소 농도 및 질산화 효율이 변동하였지만 평균 90%의 질산화효율을 나타내었으며, 유리 암모니아성 질소의 농도가 1 mg/L 이상으로 측정되었던 $1.8kg\;NH_3-N/m^3{\cdot}day$의 암모니아 부하부터 아질산성 질소의 축적이 시작되었다. 아질산성 질소가 축적되었던 기간에는 유입수의 암모니아성 질소 농도와 반응조내의 용존산소 농도 간의 비가 100 이상이거나 처리수 $NH_3-N$ 농도와 반응조 DO 농도 간의 비가 2 이상이었다. 결론적으로, 활성탄 유동상 반응조는 고농도로 암모니아성 질소를 함유하는 폐수의 생물학적 질산화에 효과적이며, 아질산화-탈질에도 유려할 것으로 판단된다.