• Journal of the Korean Chemical Society
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• v.65 no.4
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• pp.249-253
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• 2021

Litter and manure were obtained at a cow house of a livestock farm in Andondg city. We examined the change of formation of nitrogen and phosphorous from these samples and tried to suggest a more useful and realistic way for removing them. Constituent and its content of sample were identified by XRF. NO₂^-, NO₃^-, and PO₄^3- ions and NH₄⁺, T-P and T-N released from sample were analyzed using ion chromatograph and UV/Vis spectrometry, respectively. As the results of this study, the ammonia nitrogen in the early stage of cow excretion is a need to make an ammonia gas state that can be immediately volatile by increasing the pH. Nitrogen and phosphorous, the main source of nutrition in green algal bloom can be removed by transforming insoluble salts such as calcium phosphate (CaHPO₄·3H₂O) and struvite (NH₄MgPO₄·6H₂O), respectively, with addition of Ca and Mg after stimulating fermentation of manure.

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.1047-1058
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• 2003

Seasonal occurrence of high ammonia nitrogen(NH3-N) concentrations has hampered chemical treatment processes of a water plant that intakes water at Buyeo site of Geum river. Thus it is often needed to quantify the effect of Daecheong Dam ouflow on the mitigation of $NH_3$-N contamination. In this study, multiple regression models were developed for forecasting daily $NH_3$-N concentrations using 8 years of water quality and dam outflow data, and verified with another 2 years of data set. During model development, the coefficients of determination($R^2$) and model efficiency($E_{m}$) were greater than 0.95. The verification results were also satisfactory although those statistical indices were slightly reduced to 0.84∼0.94 and 0.77∼0.93, respectively. The validated model was applied to assess the effect of different amounts of dam outflow on the reduction of $NH_3$-N concentrations in 2002. The NH3-N concentrations dropped by 0.332∼0.583 mg/L on average during January∼March as outflow increases from 5 to 50cms, and was most significant on February. The results of this research show that the multiple regression approach has potential for efficient cause and effect analysis between dam outflow and downstream water quality.

• Proceedings of the Korea Water Resources Association Conference
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• 2006.05a
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• pp.457-461
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• 2006

비점원 농촌유역으로부터 강우시 영양물질(질소, 인)의 유출특성을 파악하기 위해 2002년부터 2005년까지 5개의 강우사상을 대상으로 $2{\sim}12$시간 간격으로 유량 및 수질을 측정하였다. 강우사상시 TN농도는 유량이 증가함에 따라 상승하여 최대농도를 보인 후, 유량감소에 따라 농도가 감소하는 경우와 초기농도보다 높은 농도로 유지되는 경우의 두 가지 경향을 보였다. TP농도는 유량의 증가에 따라 급격한 상승을 보였고, 최대 값 이후 농도가 낮아져 거의 초기농도에 도달하였다. 또한, 초기농도에 대한 최대농도값의 비는 TP가 TN보다 크게 나타났다. 농촌 소유역에서의 초기유출현상(first-flush)은 40%의 누적유출량을 나타낼 때 TP의 누적유출부하량은 $70{\sim}86%$를 기록하여, 도시유역(60%)과 광역논(50%)보다 크게 나타났는데, 이는 농촌 소유역이 경사가 크고 밭 등에서 강우로 인한 토양침식 등의 영향을 크게 받기 때문으로 사료된다. 4개의 강우사상에 대한 질소의 용존성 성분의 비(TN/TDN비)는 93.6%를 나타내 질소는 대부분 용존성 형태로 유출되는 것으로 나타났고, 인의 용존성 성분의 비(TP/TDP비)는 25.4%를 나타내 인의 대부분 입자성 형태로 유출되는 것으로 나타났다. 따라서, 비점원 농촌유역으로부터 TN부하를 저감시키기 위해서는 용존성 성분을 제공하는 비료의 시용량을 줄여야 하며, TP부하를 저감시키기 위해서는 강우시 입자성 인의 유출을 제어해야 한다. 이를 위해서는 비가 많이 오는 여름철에 나지(裸地)나 밭에 식생이나 멀칭(mulching) 등으로 토양침식을 방지하는 대책이나 하천변에 완충역(riparian buffer zone)을 설치하는 대책이 필요하다. 저수지 관리를 효과적으로 수행하기 위해서는 저수지 내부의 탁도 거동을 정확히 예측할 수 있어야 한다. 따라서 추후 동수역학 및 열역학에 기초한 3차원 수치모형 연구와 성층흐름에 정밀한 밀도류 실험연구 및 이에 대한 적용이 필요할 것으로 판단된다.함으로써 정보의 질적보장과 정보전환의 표준화방안을 제시하는 정보분석시스템이다.이용, 수자원의 지속적 확보기술의 특성에 따른 4개의 평가기준과 26개의 평가속성으로 이루어진 2단계 기술가치평가 모형을 구축하였으며 2개의 개별기술에 대한 시범적용을 실행하였다.하는 것으로 추정되었다.면으로의 월류량을 산정하고 유입된 지표유량에 대해서 배수시스템에서의 흐름해석을 수행하였다. 그리고, 침수해석을 위해서는 2차원 침수해석을 위한 DEM기반 침수해석모형을 개발하였고, 건물의 영향을 고려할 수 있도록 구성하였다. 본 연구결과 지표류 유출 해석의 물리적 특성을 잘 반영하며, 도시지역의 복잡한 배수시스템 해석모형과 지표범람 모형을 통합한 모형 개발로 인해 더욱 정교한 도시지역에서의 홍수 범람 해석을 실시할 수 있을 것으로 판단된다. 본 모형의 개발로 침수상황의 시간별 진행과정을 분석함으로써 도시홍수에 대한 침수위험 지점 파악 및 주민대피지도 구축 등에 활용될 수 있을 것으로 판단된다. 있을 것으로 판단되었다.4일간의 기상변화가 자발성 기흉 발생에 영향을 미친다고 추론할 수 있었다. 향후 본 연구에서 추론된 기상변화와 기흉 발생과의 인과관계를 확인하고 좀 더 구체화하기 위한 연구가 필요할 것이다.게 이루어질 수 있을 것으로 기대된다.는 초과수익률이 상승하지만, 이후로는 감소하므로, 반전거래전략을 활용하는 경우 주식투자기간은 24개월이하의 중단기가 적합함을 발견하였다. 이상의 행태적 측면과 투자성과측면의 실증결과를 통하여 한국주식시장에

• Journal of Wetlands Research
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• v.20 no.4
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• pp.417-423
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• 2018

It analyzed the efficiency of the runoff reduction of artificial reservoir by analyzing the influent and effluent of reservoir located downstream of the livestock area. Production of non point pollutants in livestock feeding areas, which is located at steep slope land, was mainly due to first flushes. Suspended Solid concentration of influent increased due to amount of rainfall, and T-P also increased over four times and 30 % of total nitrogen increased on average compared to those of dry season. While the concentration of nitrate nitrogen showed little variation, ammonia nitrogen increased over two times. The storage style nonpoint reduction facility showed the highest removal efficiency of 53 % for total phosphorus in dry weather, when the removal efficiency was 37 % for suspended solids, 10% for organic compounds, and 5 % for total nitrogen. Since algal bloom grows due to eutrophication in summer, the minus removal efficiencies of nitrogen concentration through the reservoir occurred with high frequency. Removal efficiency decreased during rainfall, showing 60 % for supended solids, and 22 % for total phosphorus. While having over nine times of capacity than the standard of non-point removal facility from Ministry of Environment, it was impounded with water during rainy season, showing not enough nonpoint removal efficiency, which indicates that maintenance is also an important factor to the nonpoint removal efficiency.

• Korean Journal of Environmental Biology
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• v.36 no.4
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• pp.680-686
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• 2018

Nitrogen fertilizers, hairy vetch, and slow-release complex fertilizers were applied to the soil during the cultivation of crops. The impact of these factors on $N_2O$ emission was quantitatively assessed and the GHGs reduction effect comprehensively evaluated. Among the three factors, the significant factors affecting $N_2O$ emission were mineral nitrogen>soil moisture>temperature. Yield and fertilizer utilization efficiency were highest in the slow-release complex fertilizer treatment. There was no significant difference in $N_2O$ emissions between the slow-release complex fertilizer treatments and the NPK+hairy vetch treatments. Comprehensive results showed that slow-release complex fertilizers treatment has high yield and fertilizer utilization efficiency but low $N_2O$ emission.

• The Korean Journal of Mycology
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• v.43 no.4
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• pp.247-252
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• 2015

Aronia (Black chokeberry, Aronia melanocarpa) belonging to the Rosaceae family, is native to eastern North America. Aronia contain high levels of flavonoids, mostly anthocyanins and proanthocyanidins, which are known as condensed tannins. The dominant proanthocyanidins in aronia are (-)-epicatechin and (+)-catechin. The concentration of proanthocyanidins in aronia is higher than in other berries, however due to the astringent taste it is not desirable for consumption. Therefore, the purpose of this study is to evaluate the effect of aronia on the reduction in tannins by yeast isolated from regional Jeotgal. We isolated strains of yeast with high ${\beta}$-glucosidase activity from Jeotgal, with the MTY2 strains exhibiting a reduction in final tannin concentration according to thin layer chromatography (TLC) analysis. MTY2 was confirmed as Kazachstania servazzii using an 18S rDNA sequence and named as K. servazzii MTY2. K. servazzii MTY2 showed most significant growth when K. servazzii MTY2 was cultured in a solution of 10% (w/v) glucose, 3% (w/v) tryptone and 0.1% (w/v) sodium chloride. According to the high performance liquid chromatography (HPLC) analysis, the (+) - catechin peak is present, but (-) - epicatechin peak was reduced at culture condition added with 10% glucose in medium.

• Food Science and Preservation
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• v.24 no.6
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• pp.771-777
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• 2017

Although Doenjang is a representative traditional fermented food in Korea, made mainly from soybeans, it has been classified into a food group identified as having high sodium in the National Health and Nutrition Examination. It is necessary to develop a low sodium Doenjang to prevent the excessive sodium intake which may cause various diseases. However, the development of Doenjang with low sodium, without significant changes on quality, is an ongoing challenge. Therefore, the experiment was designed to reduce the salt content of the soaking water to 12.5-45%. The pH, saltiness. moisture, sodium, color, amino-type nitrogen, free amino acids and constituent amino acids composition of Doenjang were investigated to determine the effect of this salt reduction on the sensory quality of Doenjang. The reduction of sodium did not affect the pH, moisture and saltiness, and this changed maintained the same range as the control. The sodium content was reduced proportionally, and the amino acid nitrogen level was 500 mg%. Therefore, this study considered that a reduction of 25% of salt in the soaking water does not affect the quality of the Doenjang while reducing the sodium content of the final Doenjang.

• Applied Chemistry for Engineering
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• v.34 no.6
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• pp.665-669
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• 2023

The crude methylnaphthalene oil (CMNO) contains nitrogen compounds (NCs) such as quinoline (QU), isoquinoline (IQU), and indole (IN). These NCs in the CMNO are treated as impurities contained in the CMNO due to contamination of the atmospheric environment and unpleasant odors. In order to improve the quality of CMNO, this study examined the effect of extraction experimental factors on the reduction of NCs contained in CMNO using CMNO as a raw material and an aqueous formamide solution as a solvent, respectively. The increase in the volume ratio of solvent to feed in initial (S/F)₀ in initial increased the distribution coefficient of NCs and the selectivity of NCs in reference to 2-methylnaphthalene (2MNA). Additionally, an increase in operating temperature (T) increased the distribution coefficient of NCs but conversely decreased selectivity. The compositions of QU, IQU, and IN in the raffinate oil recovered through equilibrium extraction under a constant condition (volume fraction of water to solvent in initial (y_w,0) = 0.1, (S/F)₀ = 9, T = 303 K, liquid-liquid contacting time = 72 h) were reduced by about 58.5 wt%, 61.9 wt%, and 73.4 wt%, respectively, compared to those of CMNO. The formamide extraction method in this study was expected to be an effective reduction method for NCs contained in CMNO.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.6
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• pp.599-608
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• 2010

The effect of silica(fumed) on nitrate reduction by zero-valent iron(ZVI) was studied using batch experiment. The reduction of nitrate was tested in three different aqueous media including de-ionized water, artificial groundwater and real groundwater contaminated by nitrate. Kinetics of nitrate reduction in groundwater were faster than those in de-ionized water, and first-order rate constant($k_{obs}$) of ZVI/silica(fumed) process was about 2.5 time greater than that of ZVI process in groundwater. Amendment of Silica(fumed) also decreased ammonium presumably through adsorption on silica surface. The pHs in all processes increased due to oxidation of ZVI, but the increase was lower in groundwater due to buffering capacity of groundwater. The result also showed amount of reduced nitrate increased as initial nitrate concentration increased in groundwater. Separate adsorption isotherm experiments indicated that fumed silica itself had some degree of adsorption capacity for ammonium. The overall results indicated that silica(fumed) might be a promising material for enhancing nitrate reduction by ZVI.

• Journal of Korean Society of Environmental Engineers
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• v.37 no.10
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• pp.578-582
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• 2015

It was investigated whether the removal of nitrogen ions included livestock wastewater were increased by increasing the reaction time of livestock wastewater and microbubbles with catalyst. For this study, the nitrogen reduction system using microbubbles with catalyst was used. The two reactors were consecutively arranged, and the second reactor (Step 2) was located to next the first reactor (Step 1). Each reactor was reacted for 2 hours and air or oxygen as oxidant was fed into the reactor during operation before microbubble device. When oxygen was used, ammonia nitrogen was removed each 18.3% and 52.8% during 2 (only step 1) and 4 (step 1 and step 2) hours reactions. This value was higher than that of when air was fed. When oxygen was used, the longer the reaction time, the ammonia nitrogen removal was higher. The longer the reaction time, the higher the nitrite and nitrate was also removed such as ammonia nitrogen. Also this system was examined whether organic matter removal is effective. The total chemical oxygen demand (TCOD) removal was higher than the soluble chemical oxygen demand (SCOD). Some materials among causing substances COD were difficult to decompose biologically. Therefore, it means that it will be easy to operate the biological processes following step and reduce the concentration of organic contaminants in effluent.