• 한국물환경학회지
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• 제22권5호
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• pp.943-951
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• 2006

Spatial distribution of water pollution in the Gap Stream was investigated from October to November, 2005. Sampling was conducted three times including effluents discharged from a wastewater treatment plant (WWTP) and a dam reservoir during the low-flow period. As a typical urban stream, total nitrogen and inorganic nitrogen concentrations increased toward downstream. Ammonia concentration was the highest in the treated water of the wastewater treatment plant and the lowest nitrate concentration was found in the effluent of the dam reservoir. A part of soluble reactive phosphorous (SRP) in total phosphorous was 22~54% in the upstream reach of WWTP in the Gap Stream whereas 68~73% in the downstream reach. Mean chlorophyll-a concentration ranged from 1.6 to $11.0{\mu}g/L$ and it tends to increase toward downstream except for WWTP effluent. As expected, untreated wastewater and WWTP effluent were suggested as the major sources of water pollution in the Gap Stream. In this study, the water pollution of the Gap Stream is a significant undergoing typical eutrophication, caused by excessive phosphorus and nitrogen nutrients from WWTP located in the watershed. As a result, the critical factor for the water pollution was evaluated to dissolved inorganic nitrogen and phosphorus nutrients. Particularly, SRP is a most important for the eutrophication. It suggest that may occur in the most urban streams of Korean peninsula. Therefore, because the necessity of water pollution management in the urban stream, inorganic N and P nutrients should be included as an essential component of water quality criteria in the advanced water quality project of Korean Government by enforcing of water quality assessment and total maximum daily loads (TMDLs).

• 유기물자원화
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• 제28권3호
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• pp.5-14
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• 2020

본 연구는 돈분과 사과착즙박 혼합 혐기소화액의 호기성 처리 과정에서 황산(H₂SO₄)을 이용한 혐기소화액의 pH를 7.0과 6.5 조절 처리가 암모니아 휘발과 화학적 특성 변화에 미치는 영향을 구명하기 위하여 수행하였다. 혐기소화액은 0.3 ㎥ air/㎥·min 조건에서 60일 동안 폭기처리를 실시하였다. 무처리구의 혐기소화액은 호기성 액비화 과정 중 pH가 상승하고, EC와 T-N 함량이 감소하는 경향을 나타내었다. 황산 무처리 혐기소화액은 pH가 높아 액비화 과정에 암모니아 농도가 172.6 mg/L로 높았으나 황산 처리 pH 조절 혐기소화액은 암모니아(NH₃) 발생이 유의적으로 감소되었다. 황산 무처리 혐기소화액은 액비화 과정 중 암모늄태 질소 함량이 47.2% 감소되었다. 혐기소화액의 pH 조절 처리구는 암모늄태 질소의 함량이 황산 처리 pH 조절 처리구에 비하여 높았다. 또한, 황산(H₂SO₄)처리는 혐기소화액에서 질소, 인산 함량의 증가에 영향을 주어 비료 성분이 높아지는 효과를 나타내었다. 따라서 혐기소화액의 황산 첨가에 의한 pH 조절은 호기성 액비화 공정에서 암모니아 휘산 저감과 질소 함량을 높이기 위한 유용한 방법으로 활용될 수 있을 것이다.

• 생태와환경
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• 제43권4호
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• pp.459-470
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• 2010

In this study, we analyzed fish tolerance guilds in mainstems and tributaries of 65 streams and rivers arid their relations to water quality using dataset sampled from April to November, 2009. For the study, water quality parameters including biochemical oxygen demand (BOD), electric conductivity (EC), total nitrogen (TN), total phosphorus (TP), ammonia nitrogen ($NH_3$-N), nitrate nitrogen ($NO_3$-N) and phosphate phosphorus ($PO_4$-P) were analyzed in the laboratory and also tolerance ranges in 3 category fishes of sensitive, intermediate, and tolerant species with high abundance were analyzed. According to fish guild analysis, tolerant species was 58% of the total community and the proportion of omnivore species was 63% of the total, indicating a degradation of habitats and water quality. Water quality was shown typical longitudinal gradients from the headwater to the down-river; TN and TP increased toward the down-rivers except for the big point-source area and ionic contents, based on, electric conductivity showed same pattern. Tolerance guild analysis of 9 major species with high abundance indicated that sensitive groups had narrower tolerance range in the water quality than the groups of intermediate and tolerant species. In contrast, tolerant groups including Zacco platypus, Carassius auratus, and Opsarichthys uncirostris amurensis had wider tolerance ranges than the groups of sensitive and intermediate species. Thus, each group was evidently segregated from the tolerance levels. Principal Component Analysis (PCA) employed for the relations of water quality to fish species in each groups suggests that water quality had highest eigenvalues with fish species in the 1st axis of the PCA and nitrogen (TN, $NH_3$-N, $NO_3$-N) and phosphorus (TP) were key components differentiating three groups of sensitive, intermediate and tolerance guilds.

• 한국수산과학회지
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• 제29권6호
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• pp.828-836
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• 1996

The histological changes of gill, liver, spleen and muscle, and respiration and blood variables and liver glycogen content were examined in black seabream, Acanthopagrus schlegeli. Fish were exposed to a high level of total ammonia nitrogen (10.4 mg/l) and recovered from exposure $(0.4{\pm}0.2mg/l)$ in a closed recirculating seawater system. In the process of exposure, mortality was $9\%$, and hyperplasia, necrosis or inflammation appeared in all tissues except for muscle. Oxygen consumption was decreased by $49\%$, and red blood cell (RBC) number, hematocrit and hemoglobin concentration were significantly decreased, while plasma glucose contents, activities of glutamate-oxaloacetate transaminase (GOT) and glutamate-pyruvate transaminase (GPT) increased. Liver glycogen content significantly increased from $6.6\%\;to\;10.4\%$. A large amount of hemosiderin was observed in the splenic tissue. During the recovery period, RBC number, hematocrit, hemoglobin concentration, GOT and GPT activities were returned to the normal status. Histological status of liver tissue was returned to the normal, but liver glycogen content was not recovered. During the recovery period, spleen melanin-macrophages temporarily increased, but subsequently decreased to the normal status.

• 한국식품과학회지
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• 제4권4호
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• pp.276-284
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• 1972

1. 장류에 관여(關與)되는 된장, 메주, 청국장, 볏짚등에서 14균주를 분리하고 그 중(中)에서 protease와 amylase 생산력(生産力)이 크고 amino-N를 적게 유리(遊離)하며 많은 ammonia-N을 생산(生産)하는 Bacillus 속의 3균주($K_{S}-1\;K_{S}-7\;K_{M}-9$)를 선발(選拔)하고 그 중(中)에서 우수한 $K_{M}-9$를 Bacillus liceniformis로 동정(同定)하여 이 균(菌)으로 콩과 밀의 배합비(配合比)를 달리하여 메주를 만들고, 간장을 담그어서 간장숙성과정중(熟成過程中)의 성분변화(成分變化)를 검토(檢討)한 결과(結果) 세균(細菌)만으로도 간장 제조(製造)가 가능(可能)했다. 2. 원료처리(原料處理) 및 숙성기간, 콩과 밀의 배합등(配合等)에 따른 간장 덧중의 성분변화(成分變化)는 다음과 같다. 1) 세균(細菌)메주 중에 전분질이 많고 단백질이 적을수록, 메주를 건조해서 담글 때, 또 담근간장이 숙성될수록 간장원료 밀을 증가하는 것보다 볶는 것이 간장 덧중의 ammonia-N 가 감소(減少)되었다. 즉(卽) 원료배합비에 따른 30일 숙성간장 덧중의 ammonio-N 는 콩과 밀이 3 : 0, 2 : 1, 1: 1, 1 : 2, 0 : 3, 일 때 0.51, 0.46, 0.36, 0.204, 0.03%로 점점 감소를 보였고, 보통 간장 덧의 $0.22%^{(26)}$보다 원료 1 : 1 이상에서는 다소 많았다. 5, 15, 30, 50일의 숙성기간 별(別)로는 콩과 밀이 1 : 1 일때 0.38, 0,364, 0.360, 0.105%로 점점 감소된 것을 볼 수 있었다. 또한 원료 처리에 따른 50일 숙성간장에서 건조한 메주로 담근 간장 덧에는 ammonia-N 가 0.034%인데 건조하지 않은 것에서는 0.105%이다. 또한 볶은 밀로 담근 간장 덧중에서 ammonia-N 가 0.16%이가 증자한 밀로 담은 것은 0.29%이다(5일 숙성된 간장덧). 2) 간장 덧중의 유리(遊離)총질소는 숙성 4주까지는 증가(增加)하고 그 후(後)에는 감소되었다. 그리고 amino-N는 계속 증가하였다. 3) 간장 덧중의 total acid는 숙성 30일 까지는 증가되고 그 후에는 감소되는바 숙성기간 5, 15, 30, 50일별(別) total acid는 2.56, 2.95, 4.14, 1.97로 증감되었다. 개량간장 덧 $1.15%^{(26)}$, $1.80{\sim}1.98%^{(27)}$에 비(比)하여 많았고 콩과 밀의 배합비(配合比)로 보면 3 : 0 에서 3.25, 2 : 1에서 2.07, 1 : 1에서 1.97덧로 전분질이 많고 단백질이 적어짐에 따라 감소되었다.(50일 숙성 간장덧). 메주의 건조는 간장덧중에 처음부터 많은 산량(酸量)을 나타내고 서서히 증가 또는 유지되다가 30일경에 이르면 감소되었고 건조한 메주와 건조하지 않은 메주는 숙성 30일 후에 일치점을 나타내었다. 4) pH의 변화는 배합량(配合量)이 많아짐에 따라 점점 낮아지고, 콩의 배합량이 많아짐에 따라 높아졌다. (콩: 밀이 3 : 0, 2 : 1, 1 : 1, 1 : 2, 0.3에서의 pH는 각각 6.3, 5.2, 5.1, 4.85, 4.75)이었다. 숙성기간에 따라선 큰 차이(差異)를 보이지 않았고 건조한 메주로 담근 간장덧의 pH는 건조하지 않은 메주로 사용한 것보다 다소 높았으며, 개량 및 재래간장의 pH와 거의 일치하였다.

• Journal of Applied Biological Chemistry
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• 제43권2호
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• pp.86-93
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• 2000

An experiment was conducted to obtain the quantitative data on the transformation and loss of applied urea-N in waterlogged soil columns. The soil columns were pre-incubated for 35 days to develop oxidized and reduced soil conditions prior to urea application. After urea application at the rate of $150kg\;N\;ha^{-1}$(29.5 mg N), the amounts of nitrogen which were volatilized, leached, and remained in soil column were measured during 38 days of incubation period. On 2 and 4 days of incubation, 54.1%(15.9 mg N) and 98.4%(29.0mg N) of the applied urea was hydrolyzed, respectively. Most of the applied urea was completely hydrolyzed within 6 days. After urea application, the rates of ammonia volatilization were increased with the floodwater pH when the floodwater pH were higher than 7.0. The maximum rate of ammonia volatilization was $0.3mg\;d^{-1}$ when pH of the floodwater showed maximum value of 7.6. The total amount of volatilized nitrogen was 6.1% (1.8mg N) of the applied urea-N. A 63.2 % (18.6mg N) of the applied urea was remained in soil as $NH_4{^+}-N$ and 28.0% (8.2mg N) of the applied urea was leached as $NH_4{^+}-N$ at the end of the incubation. Amount of $NO_3{^-}-N$ in soil was smaller than 2.0 mg throughout the incubation period. The total amount of $NO_3{^-}-N$ leached was very small, which value was 1.8 mg. It suggested that nitrification process was not significant in waterlogged soil column of this study due to high infiltration rate of urea solution applied to the soil column. Therefore only small amount of $NO_3{^-}-N$ was lost by denitrification and leaching process.

• 한국초지조사료학회지
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• 제42권4호
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• pp.264-269
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• 2022

본 연구에서는 미생물 첨가에 따라 거세한우 비육우 분의 이화학적 특성, 미생물 성상, 가스발생량 및 퇴비 부숙도에 미치는 영향을 규명하고자 수행하였다. 이상의 결과를 종합하면, 4주 후, 미생물 첨가구에서 수분, 유기물, 총질소 함량 및 pH가 낮았으며, 나머지 이화학적 특성에서는 차이가 나타나지 않았다. 유산균과 효모균 수는 증가하였으며, 대장균 수는 감소하였다. 12주 후, 미생물 첨가구에서 유산균과 고초균 수는 높았으나, 수분, 효모 및 대장균 수는 낮게 낮았다. 하지만 암모니아, 황화수소 발생량과 퇴비 부숙도는 미생물 첨가에 의한 효과가 나타나지 않았다. 따라서, 거세한우 분에 미생물을 첨가하면 유익균은 증가하고, 병원성 미생물은 감소하여, 비육우의 생산성은 증진될 것으로 사료되지만, 가스 발생량 및 퇴비 부숙도에 대한 추가적인 연구는 지속적으로 수행되어야 할 것으로 사료된다.

• Membrane and Water Treatment
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• 제7권1호
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• pp.11-22
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• 2016

The characterization of treatment performance with respect to mixed liquor suspended solids (MLSS) concentration enables greater control over system performance and contaminant removal efficiency. Hybrid membrane bioreactors (HMBRs) have yet to be well characterized in this regard, particularly in the context of greywater treatment. The aim of this study, therefore, was to determine the optimal MLSS concentration for a decentralized HMBR greywater reclamation system under typical loading conditions. Treatment performance was measured at MLSS concentrations ranging from 1000 to 4000 mg/L. The treated effluent was characterized in terms of biochemical oxygen demand ($BOD_5$), chemical oxygen demand (COD), turbidity, ammonia ($NH_3$), total phosphorus (TP), total kjeldahl nitrogen (TKN), and total nitrogen (TN). An MLSS concentration ranging from 3000 to 4000 mg/L yielded optimal results, with $BOD_5$, COD, turbidity, $NH_3$, TP, TKN, and TN removals reaching 99.2%, 97.8%, 99.8%, 99.9%, 97.9%, 95.1%, and 44.8%, respectively. The corresponding food-to-microorganism ratio during these trials was approximately 0.23 to 0.28. Operation at an MLSS concentration of 1000 mg/L resulted in an irrecoverable loss of floc, and contaminant residuals exceeded typical guideline values for reuse in non-potable water applications. Therefore, it is suggested that operation at or below this threshold be avoided.

• 한국물환경학회지
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• 제36권2호
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• pp.137-147
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• 2020

A direct contact membrane distillation (DCMD) was applied to treat strong nitrogenous wastewater of anaerobic digestion supernatant (ADS) and human urine (HU). The ammonia transfer was evaluated in terms of specific ammonia transfer (SAT) value, which is the ratio of total ammoniacal nitrogen divided by the amount of water transferred. The acidification resulted in low SAT values and high quality of produced water. The ammonia transfer control in the acidic condition was stronger for HU than ADS due to higher alkalinity (pH 8.8) and ammonia concentration (5700 mg-N/L) of HU. Acidified HU at pH 4 exhibited a SAT value of 1.64 × 10^-5, which was significantly smaller than the SAT value of 3.00 × 10^-3 for the original HU. The low pH enhanced the water flux for ADS, but HU showed a steep decrease in water flux due to enhanced fouling. It was considered that the fouling intensity in acidic conditions depends on the characteristics of the wastewater source. The major foulants on the MD membrane were NaCl, CaCO₃ and CuSO₄ as recognized by the SEM-EDS. Acidified ADS and HU at pH 4 showed relatively high N content of 8.18 % and 28.03 %, respectively, as organic fouling.

• Journal of Animal Science and Technology
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• 제65권1호
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• pp.96-112
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• 2023

Rye (Secale cereale L.) is a valuable annual forage crop in Korea but there is limited information about the impact of chemical and biological additives on fermentation characteristics of the crop. This experiment was conducted to investigate fermentation dynamics of wilted forage rye treated with the following six additives; control (no additive), sodium diacetate applied at 3 g/kg wilted forage weight (SDA3), 6 g/kg wilted forage weight (SDA6), inoculations (10⁶ CFU/g wilted forage) of Lactobacillus plantarum (LP), L. buchneri (LB), or LP+LB. The ensiled rye sampled at 1, 2, 3, 5, 10, 20, 30, and 45 days indicated that the acidification occurred fast within five days of storage than the rest of the storage period. The microbial inoculants decline the pH of ensiled forage, more rapidly than the control or SDA treated, which accompanied by the decrease of water-soluble carbohydrates and increase of lactic acid. Compared with the control silage, all treatments suppressed ammonia-nitrogen formation below to 35 g/kg DM throughout the sampling period. Suppression of total microbial counting occurred in SDA6, LP, and LP + LB. The lactic acid production rates were generally higher in microbial inoculation treatments. Acetic acid concentration was lowest in the LP-treated silage and highest in the SDA- and LB-treated silages. The in vitro dry matter (DM) digestibility and total digestible nutrients were the highest in the silage treated with SDA (6 g/kg) at day 45 of ensiling. Based on lower ammonia-nitrogen concentrations and higher feed value, ensiling forage rye treated with SDA at 6 g/kg is promising through enhanced silage quality.