• 환경위생공학
• /
• 제16권3호
• /
• pp.42-53
• /
• 2001

This study were conducted to estimate property of nitrogen dioxide concentration at industrial areas in Korea. The nitrogen dioxide concentrations were measured for 50 dwellings at Ulsan and Yeochon, respectively using the nitrogen dioxide filter badge forming the passive sampler from summer time 1998 to winter time 1999. The major results obtained from this study were as follows: 1. The mean indoor, outdoor, and personal concentrations of nitrogen dioxide during summer time 1998 in Ulsan were 28.9 ppb, 24.8 ppb, 24.8 pub, respectively. 2. The mean indoor, outdoor, and personal concentrations of nitrogen dioxide during winter time 1999 in Yeochon were 11.4 ppb, 12.5 ppb, 15.5 ppb, respectively. 3. The mean concentration of nitrogen dioxide during winter time 1998 were higher than the corresponding levels during summer time 1997 in Ulsan. 4. The mean concentration of nitrogen dioxide in Ulsan were in general higher than the corresponding levels in Yeochon. 5. This results in slightly positive correlation among indoor, outdoor, and personal nitrogen dioxide concentrations for summer time in Ulsan, then it statistical significance is showed(p <.05). These results suggest that nitrogen dioxide concentrations in industrial areas seem to be affected by traffic density and conditions of industrialization.

• 한국물환경학회지
• /
• 제30권5호
• /
• pp.503-511
• /
• 2014

The temporal and spatial analyses of total nitrogen (TN) fractionation were conducted in order to understand 1) total nitrogen components in streams and 2) their patterns in rainy and dry seasons. The result showed that the concentration of nitrogen components in stream water was lower in non-urban area and getting higher in urban area. Dissolved total nitrogen (DTN) was 95~97.7% of total nitrogen in streams, and the proportion of dissolved organic nitrogen (DON) and ammonia nitrogen ($NH_3-N$) was higher with increasing urban area. The concentration of total nitrogen and nitrate nitrogen ($NO_3-N$) were highest in winter among four seasons. The result was showed that concentration of $NH_3-N$ was same variation as concentrations of TN and $NO_3-N$ in urban-rural complex and urban areas, except rural areas. During rainy season, concentrations of particulate organic nitrogen (PON) and $NH_3-N$ increased in rural areas and decreased in both urban-rural complex and urban areas. Correlation between total nitrogen components and land uses was positively correlated with site > paddy, and negatively correlated with forest. The variation of total nitrogen concentration was determined by $NO_3-N$ in non-urban areas, by $NO_3-N$ and $NH_3-N$ in urban-rural complex and by $NH_3-N$ in the urban areas.

• 대한환경공학회지
• /
• 제29권4호
• /
• pp.460-465
• /
• 2007

본 연구에서는 고농도 암모니아성질소로 오염된 고체배지로부터 분리해 낸 Leclercia adecarboxylata를 이용하여 암모니아성질소의 제거특성 및 기작을 파악하여 폐수처리의 적용가능성에 대해 살펴보았다. 질소제거에 있어서 가장 널리 알려진 생물학적 질산화와 후탈질에 의한 질소의 대기로의 방출이 아닌 질소합성균주를 이용한 질소의 체내합성을 이용한 영양물질의 제거 가능성에 대해 접근해 보았다. L. adecarboxylata는 무염분조건에서 암모니아성질소의 제거와 균체중식이 가장 왕성했으나, 염분이 4%를 넘어서게 되면 그 효율은 급격히 저하되었다. 약 80 mg/L의 암모니아성질소는 20시간 이내에 거의 대부분 제거되었으나, 500 mg/L인 시료는 탄소원의 부족으로 인해 50시간 이상 처리후에도 50%의 제거율에도 미치지 못해 탄소원이 많을수록 질소제거율은 높음을 알 수 있었다. 탄소원이 모두 소모되고 난 이후에는 더 이상 질소제거는 이루어지지 않았으나, 탄소원을 추가로 공급했을 때 제거효율은 다시 증가했다. 시료의 pH는 미생물의 증식에 의해 8에서 6.36까지 감소했다. 암모니아성질소가 제거되는 동안 아질산성질소와 질산성질소의 축적은 일어나지 않았고, TKN값은 큰 차이를 보이지 않은 것으로 미루어 볼 때 유기질소로의 합성을 추측할 수 있었다. 유기질소 중 단백질의 농도를 측정해 본 결과 초기시료에서는 불검출 되었으나, 48시간 경과후의 시료에는 193.1 mg/L의 단백질이 검출 되었다. 따라서 L. adecarboxylata는 암모니아성질소를 유기질소로 합성하는 능력이 탁월하여 폐수중의 암모니아성질소의 제거에 이용가치가 클 것으로 판단된다.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
• /
• pp.313-316
• /
• 2000

The effects of initial sugar concentration and the various nitrogen sources on the fermentation characteristics of Thraustochytrium aureum were investigated. The sugar conversion ratios decrease with increase in the initial sugar concentration regardless of the kinds of nitrogen sources. The specific growth rate, the biomass yield, and the DHA yield also decreased but approached constant values higher than the concentration of 30g/L. The sugar conversion ratios and the specific growth rate showed the highest values in case of using the yeast extract as nitrogen source. It was difficult to conclude that the variation of nitrogen source had some effects on the biomass yield. However, the initial sugar concentration had a rather effects on the biomass yield for the sugar concentration of 40 g/L showed 0.27. The nitrogen source that showed the greatest yield of DHA was sodium glutamate.

• 상하수도학회지
• /
• 제11권4호
• /
• pp.43-53
• /
• 1997

In this research, the synthetic livestock wastewater was prepared to study the characteristics of organic matter removal, the change of VFA production, and the amount of gas production with respect to the change of ammonium nitrogen concentration in the waste using anaerobic fixed bed process, which is an anaerobic biofilm process. The HRT and operation temperature were 1 day and $35{\pm}1^{\circ}C$, respectively. Also, the characteristics of organic matter removal and the inhibitory effect on microorganism in the anaerobic process were studied on the organic loading and ammonium nitrogen concentration. The results obtained were as follows: For COD loading of $10kg/m^3$-day and five levels of ammonium nitrogen concentration ranging from 1,000 to 5,000 mg/L, organic removal efficiencies were about 81, 74, 67, 58, and 51%, and gas productions were 3,860, 3,520, 3,240, 3,020, and 2,790 ml/l-day, respectively. Average methane contents in the gas produced on COD loading of $10kg/m^3$-day was about 76%. Throughout the whole period of experiment, remaining VFA (as COD base) in the effluent was over 90% of remaining COD. This result indicated the inhibitory effect of high concentration of ammonium nitrogen through the facts that accumulated VFA was almost COD and organic removal efficiency decreased also with the increase of ammonium nitrogen. Especially, that implys which high concentration of ammonium nitrogen not only inhibits methane forming bacteria, but also acid forming bacteria.

• 한국축산시설환경학회지
• /
• 제6권2호
• /
• pp.65-72
• /
• 2000

This study was conducted to investigate the effects of artificial filaments equipped in the aeration tank of aerobic·fermentation system on the removal efficiency of swine wastes which were fermented an aerobically and thus containing high nitrogen. Two aerobic fermentation system each consist4s of 4 tanks ; storage tank, 1st and 2nd aeration tank and settling tank were run before and one or three weeks after equipment of artificial filament in the aeration tanks. Total solids concentration tended to increase by aerobic fermentation in all running periods. However, decreased(P<0.05) total nitrogen concentration was shown three weeks after the equipment of artificial filament. Ammonia nitrogen concentration also largely decreased(p<0.05) in both running periods of one and three weeks after equipment of artificial filaments. These results suggest that the artificial filaments may improve the removal efficiency of nitrogen in swine wastewater containing high nitrogen during aerobic fermentation.

• 한국물환경학회지
• /
• 제23권6호
• /
• pp.993-997
• /
• 2007

The upflow anaerobic sludge blanket (UASB) reactor can be effective for treating simple organic compounds containing high concentration of ammonia nitrogen. The chemical oxygen demand (COD) removal efficiency was about 80% at ammonia nitrogen concentration up to 6,000 mg-N/L. This result also showed that it would be possible to treat propionate effectively at free ammonia nitrogen concentration up to 724 mg-N/L if sufficient time was allowed for adaptation. However the specific methanogenic activity (SMA) of granule was lower than that of granule in the reactor with lower ammonia nitrogen concentration. At 8,000 mg-N/L, the inhibition of high ammonia concentration was observed with evidence of increase of the volatile suspended solids (VSS) concentration in the effluent. It might be ascribed to the decrease in the content of extracellular polymer (ECP), which resulted to the sloughing off of obligated proton-reducing acetogens and heterogenotrophic methanogens from the exterior of granular sludge. This caused a great portion of the finely sludge to be easily washed out. Therefore, failure to maintain the balance between these two groups of microorganism cause accumulation of the hydrogen partial pressure in the reactor, which could have inhibited the growth of acetate utilizing methanogens.

• Environmental Engineering Research
• /
• 제24권2호
• /
• pp.238-245
• /
• 2019

This study investigated the characteristic of aerobic granular sludge (AGS) process to treat the sewage having low carbon/nitrogen ratio (Biochemical oxygen demand ($BOD_5$):Total nitrogen (T-N), 4.5:1) in sequencing batch reactor (SBR). The removal efficiency of $BOD_5$, suspended solid (SS), T-N and phosphorus ($PO_4{^{3-}}$-P) were 92.6%, 64.3% and 90.1%. Concentration and size of AGS were changed in proportion to the organic matters and nitrogen concentration of the influent (Concentration and size of AGS: 1,700-3,000 mg/L, 0.5-1.0 mm). Mixed liquor suspended solid (MLSS) also changed with the concentration of AGS (MLSS: 2,000-3,500 mg/L). When the settling time was shortened from 15 min to 10 min, size and shape of AGS were maintained (Size of AGS: 1.0-1.5 mm). In addition, the concentration of AGS and MLSS increased (Concentration of AGS: 3,500 mg/L, MLSS: 4,000 mg/L). Concentration, size and shape of AGS were affected the settling time of the reactor more than the concentration of organic matter and nitrogen in the influent. In the results of removal efficiency and changes in AGS, we confirmed that the SBR process using AGS can be used to treat the sewage having low carbon/nitrogen ratio by applying short settling time.

• Journal of Nutrition and Health
• /
• 제28권5호
• /
• pp.406-414
• /
• 1995

Nitrogen(N) concentration of preterm(PT) and term (T) milk in various fractions, such as total, protein, nonprotein, whey protein and casein were determined at 2-5 days, 1, 2, 4 and 6 weeks of postpartum. The purpose of this study was to investigate the nitrogen concentration of human milk from mothers delivering at preterm and term, and the propriety of preterm milk for premature infants. The concentration of total N, nonprotein N, protein N, whey protein N and casein N in preterm milk was decreased significantly with time postpartum. Total N was 374mg/이 at colostrum, 232mg/dl at mature milk. Whey protein N was decreased from 42mg/dl at 2-5 days to 32mg/dl at 4-6 weeks. Protein N was 332mg/dl at colostrum, 202mg/dl at mature milk. The proportion of whey protein N and casein N were 39:61 at colostrum, 28:72 at mature milk. No difference were found between T and PT milk for total nitrogen excepted 2 weeks. In this report we show that nitrogen concentration except casetpt casein N is smaller in milk from mothers giving birth prematurely than in milk from mothers giving birth at term, over the first two weeks of lactationl But protein N was higher in preterm milk than term milk, whey protein nitrogen was lower. By comparing predicted nitrogen intakes to estimated requirements of preterm infants fed 150 to 200ml/kg/day of their own mother's milk, we predict that the quantities of protein provided would be adequate to meet the requirements of the prematured infants during the early weeks of life.

• 한국작물학회지
• /
• 제32권3호
• /
• pp.347-352
• /
• 1987

버어리 21을 공시품종으로 하여, 시비량을 전량기비구에서는 표준시비 외 증비 2처리와 기 추비구에서는 표준량을 기비로 하고 추비 2 처리를 두어 질소수준 및 시비방법과 수확시기의 차이가 엽중전질소 및 전알카로이드함량에 미치는 영향을 밝혀서 전질소화합물이 낮은 잎담배를 생산코자 본 시험을 수행하였던 바 그 결과를 요약하면 다음과 같다. 1. 질소 증비에 따라 부풀성이 저하되었다. 2. 질소량을 증시 할수록 성숙이 지연되었고 엽중전질소 및 알카로이드함량도 증가되었으며, 기비 보다도 추비에 의해서 그 영향이 크게 나타났다. 3. 엽중 전질소함량은 적심 전이 가장 높았고, 이후 생육기간이 길수록 감소되었는데 상위엽에서 감소폭이 더 컸다. 4. 엽중 알카로이드함량은 적심기부터 증가하여 생육기간이 길수록 점차 더 증가되었고, 상위엽에서 증자폭이 더 컸다.