• Journal of Korean Society of Water and Wastewater
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• v.24 no.1
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• pp.51-62
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• 2010

The high concentration of N in the wastewater from livestock farming generally renders the efficiency of the wastewater treatment. Therefore, removal of N in livestock wastewater is crucial for successful treatment. The current study was conducted to investigate the optimum conditions for partial nitrification under anaerobic condition following nitritation in TPAD-BNR(two-phase anaerobic digestion-biological nitrogen removal) operating system. Sequential operating test to stimulate partial nitrification in reactor showed that partial nitrification occurred at a ratio of 1.24 in $NO_2{^-}$-N:$NH_4{^+}$-N. With this result, a wide range of factors affecting stable nitritation were examined through regression analysis. In the livestock wastewater treatment procedure, the hydraulic retention time (HRT) and pH range for optimum nitrite accumulation in the reactor were 1-1.5 days and 7-8, respectively. It was appeared that accumulation of $NO_2{^-}$-N in the reactor is due to inhibition of the $NO_2{^-}$-N oxidizer by free ammonia (FA) while the effect of free nitrous acid was minimal. Nitrification was not influenced by DO concentration at a range of 2.0-3.0 mg/L and the difference in the growth rate between $NH_4{^+}$-N oxidizer and $NO_2{^-}$-N oxidizer was dependent on the temperature in the reactor.

• Journal of Life Science
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• v.13 no.1
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• pp.47-53
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• 2003

The purpose of this study is to improve the system for biological nitrogen oxidizing process in sewage and wastewater. A bacterium having high abilities to oxidize of nitrogen was one of the possessed on Lab. The strain was identified to Bacillus sp. A8-8, based on the physiological and biochemical properties. And the strain has ability degradation crude oil. In comparison with oxidizing rates with changing initial pH and temperature, the strain Bacillus sp. A8-8 was nitrogen oxidizing ability and growth rate on the various of pH, temperature. oxidizing rates of the strain in sewage and wastewater were about 48% and 62%, respectively. The nitrogen oxidizing rate was increased in proportion to the initial concentration of glucose. The microorganism, Bacillus sp. A8-8, immobilized in ceramic carrier were evaluated for the oxidation of ammonia in culture media.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.241-241
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• 2020

축산물의 수요가 증가함에 따라 가축의 사육규모 및 두수도 증가하여 가축분뇨의 발생량이 증가한다. 가축분뇨는 일반하수에 비해 고농도의 유기물, 질소, 인 등의 오염물질이 포함되어 있다. 적절한 처리 없이 하수처리장 및 수계로 유입될 경우 하수처리장 처리 효율에 영향을 미치거나 부영양화 등 다양한 문제를 야기 시킬 수 있다. 이러한 문제를 해결하기 위해 아질산화 반응을 이용하는 다양한 공정들이 연구되고 있다. 아질산화 반응은 완전 질산화 반응에 비해 질산화 단계에서 약 25%의 산소요구량이 절감되고, 탈질 단계에서 약 40%의 탄소원이 절감되는 경제적 장점이 있기 때문이다. 본 연구에서는 부피 8L의 실험실 규모 아질산화 반응조 원통형 아크릴로 제작되었고, 서울 A하수처리장 미생물을 채취하여 사용했다. 또한 SRT의 영향을 살펴보기 위하여 35℃ 동일 온도를 유지했다. 반응조 슬러지 반송 및 폐기가 없는 완전 혼합 반응조로 SRT와 HRT가 동일하게 운전하는 방법을 사용하여 SRT를 조절하는 방식으로 운전했다. SRT의 경우 8일, 6일, 4일, 2일의 변경조건을 통해서 차이를 살펴보았다. Ammonia Removal Rate(%)의 경우 각각 86%, 86%, 87%, 24%의 효율을 보였고, Nitrite Conversion Rate(%)의 경우 각각 10%, 45%, 80%, 41%의 효율을 보였다. 35℃ 실험실 규모 반응조에서 가축분뇨 유입 원수의 아질산화 반응을 유도하기 위해서는 SRT운전 조건은 4~8일, 고효율의 아질산화 반응을 유도하기 위해서는 SRT 4일 조건이 적합하다고 판단된다. 본 연구는 실제 가축분뇨 처리 효율 상승을 위해서 아질산화 공법을 도입할 경우 중요한 자료로 이용 가능할 것으로 판단된다.

• Korean Journal of Soil Science and Fertilizer
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• v.32 no.3
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• pp.304-311
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• 1999

This experiment was conducted to find out the optimum condition of aeration rates for removal of malodor and to improve the compost quality. The aspect of ammonia emission and amounts of volatilization were investigated in the enclosed composting reactor of 242 liters piled with mixed materials of dairy manure and rice straw, which adjusted to 65% of initial moisture content and controlled by four different aeration rates. Mature temperature increased suddenly in initial composting time and decreased with Increasing aeration rates. The treatment of $1.79l\;min^{-1}kg\;dry-solids^{-1}$ results in overcooling and rapid drying of composting materials because of too much aeration. The average concentration of ammonia emitted from composting for 24 days was the range of 25.3 to $239.8mg\;l^{-1}$ and was highest in the treatment of $0.09l\;min^{-1}kg\;dry-solids^{-1}$, followed by 0.90. 0.18 and $1.79l\;min^{-1}kg\;dry-solids^{-1}$. The range of maximum concentration by different aeration rates was $335{\sim}2279mg\;l^{-1}$ and it wan highest in the treatment of $0.09l\;min^{-1}kg\;dry-solids^{-1}$, followed by 0.18, 0.09 and $1.79l\;min^{-1}kg\;dry-solids^{-1}$. Relationship between the ammonia concentration emitted and temperature matured under different aeration rates showed an exponential positive correlation with 1% significance and had a trend of clear increase in ammonia concentration with increasing temperature over $50^{\circ}C$. Most of ammonia volatilized within plays after composting. The volatilization rate of ammonia ranged from 0.056 to 0.453 per dry solids of materials and it was highest in the treatment of $0.09l\;min^{-1}kg\;dry-solids^{-1}$, followed by 0.18, 0.09 and $1.79l\;min^{-1}kg\;dry-solids^{-1}$. Amounts of ammonia volatilized under composting condition of this experiment was estimated to be highest in the aeration range of 0.9 to $1.0l\;min^{-1}kg\;dry-solids^{-1}$.

• Journal of Microbiology and Biotechnology
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• v.13 no.2
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• pp.309-312
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• 2003

A bacterial strain NB01, isolated from wastewater, was found to utilize nitrobenzene (NB) as the sole source of nitrogen, carbon, and energy. The strain was classified as a member of a high G+C Gram-positive group and identified as Mycobacterium chelonae based on an analysis of its 16S rRNA gene sequence. The strain grew on NB with a concomitant release of about 63% of the total available nitrogen as ammonia, suggesting a reductive degradation mechanism. The optimal pH and temperature for degradation were PH 7.0-8.0 and $30^{\circ}C$, respectively. The cell growth was retarded at NB concentrations above 1.8 mM. The degradation of NB followed Michaelis-Menten kinetics within the tolerance range, and the $K_m$ and maximum specific removal rate for NB were 0.33 mM and $11.04\;h^{-1}$, respectively.

• Korean Chemical Engineering Research
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• v.46 no.6
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• pp.1124-1129
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• 2008

Cokes wastewater is one of the most toxic industrial effluents since it contains high concentrations of pollutants, such as phenol, ammonia, thiocyanate and cyanides. Although biological pre-denitrification process has been used to treat this wastewater in Korea, unexpected failure in nitrogen removal occasionally occurs during summer season. In this study, therefore, we examined inhibitory effects of phenol, ammonia, thiocyanate, ferric cyanide and free cyanide on biological denitrification according to temperature variation ($20{\sim}38^{\circ}C$). Batch experiments showed that denitrification rate was faster in summer ($38^{\circ}C$) than other seasons, and removal rates of pollutants increased with increasing temperature. Phenol, ammonia, thiocyanate and ferric cyanide did not inhibit denitrification even at its high concentration (200 mg/L). However free cyanide above 0.5 mg/L seriously inhibited the bilolgical denitrification reaction. Inhibitory effect of these pollutants was reduced with increasing temperature.

• Microbiology and Biotechnology Letters
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• v.34 no.3
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• pp.257-264
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• 2006

An aerobic submerged membrane bioreactor (MBR) treating ammonium wastewater was studied in respect of nitrification characteristics and distribution of nitrification bacteria over a period of 350 days. MBR was fed with ammonium concentration of 500-1000 mg $NH_4-N/L$ at a nitrogen load of $1-2kg\;N/m^3{\cdot}d$. Overall ammonium oxidation rate increased with dissolved oxygen (DO) concentration, temperature, and sludge retention time (SRT). Under a higher concentration of free ammonia ($NH_3-N$) due to the decrease of ammonium oxidation rate, the nitrite ratio ($NO_2-N/NO_x-N$) in the effluent increased. The sudden collapse of nitrification efficiency accompanied by sludge foaming and the increase of sludge volume index (SVI) was observed unexpectedly during the operation. At the later stage of operation, additional carbon source was fed to the MBR and resulted in twice higher value of SVI and the decrease of ammonium oxidation rate. In fluorescence in situ hybridization (FISH) analysis, genus Nitrosomonas which is specifically hybridized with probe NSM156 was initially the dominant ammonia oxidizing bacteria and the amount of Nitrosospira gradually increased. Nitrospira was the dominant nitrite oxidizing bacteria during whole operational period. Significant amount of Nitrobacter was also detected which might due to the high concentration of nitrite maintained in the reactor.

• Journal of the Korea Organic Resources Recycling Association
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• v.10 no.3
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• pp.117-125
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• 2002

This study experimented a possibility of advanced treatment through microorganism that converts $NH_3-N$ to organic nitrogen in wastewater contaminated by ammoniac nitrogen unlike conventional nitrogen removal process. After distributing three kinds of special bacteria that use $NH_3-N$ as a substrate, when those bacteria were cultured in no salt condition and salt condition (3% NaCl), M11 showed better growth in salt condition and M12 showed better growth in no salt condition. However M7l grew well in both no salt condition and salt condition. In the test of glucose effect, maximum growth and removal rate were observed in glucose concentration of 5g/L but in high concentration (1000mg/L as $NH_3-N$) of $NH_3-N$ growth and removal rate were low. Removal rate was the highest in 100mg/L $NH_3-N$ and the fact that concentration of $NO_2-N$ and $NO_3-N$ didn't increase assumed $NH_3-N$ was converted to organic nitrogen. Optimum concentration of $K_2HPO_4$ for phosphorous supply and buffer was 5g/L. Special bacteria distributed could use $NO_2-N$ and $NO_3-N$ as well as $NH_3-N$ as substrates. This study showed that when growth rate of bacteria was high removal rate also was high. It is possible to apply as a method to treat wastewater polluted by $NH_3-N$.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.305-306
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• 2003

To treat fulminant hepatic failure (FHF) patients, various extracorporeal bioartificial liver (BAL) systems have been developed. Several requirements should be met for the development of BAL systems: hepatocytes should be cultured in a sufficiently high density; their metabolic functions should be of a sufficiently high level and duration; and the BAL systems module should permit scaling-up and aseptic handling. Several investigators have found that freshly isolated primary hepatocytes can be cultured into three dimensional, tightly packed, freely suspended, multicellular aggregates, or spheroids. These specialized cell structures exhibited enhanced liver specific functions and a prolonged differentiated state compared to cells maintained in a monolayer culture. Cells in spheroids appear to mimic the morphology and ultrastructure of the in vivo liver lobule. The ability of hepatocytes to organize into three-dimensional structures was hypothesized to contribute to their enhanced liver-specific activities. In this study, the ammonia removal rate and urea secretion rate of pig hepatocytes spheroids encapsulated in Ca-alginate bead were determined. A packed-bed bioreactor with encapsulated pig hepatocytes was devised as BAL support system. The efficacy of the system was evaluated in vitro.

• Journal of Biomedical Engineering Research
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• v.19 no.3
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• pp.215-224
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• 1998

This paper is fundamental study to develope the extracorporeal liver support system for patient with fulminant hepatic failure(FHF) or being expected for orthotopic liver transplantation. The polyurethane foam, which is composed of the density of 33kg/m3, the average pore diameter of 500${\mu}{\textrm}{m}$, the closed window of 60-70%, was manufactured with the prepolymer of 15% NCO-, Hepatocytes were inoculated to form spheroids in polyurethane foam. The time of spheroid formation in BSA(Bovine Serum Albumin) coated polyurethane foam was shorter than that in raw polyurethane foam. To verify the function of hepatocyte spheroids, we measured ammonia removal rate, urea and albumin secretion rate. Polyurethane foam was suitable for culture of hepatocyte spheroids. And culture of hepatocyte spheroids in polyurethane foam has high possibility in using as an extracorporeal liver support system.