• Membrane and Water Treatment
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• 제9권4호
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• pp.263-271
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• 2018

The objective of this work was to analyze organic matter removal, nitrification, biomass growth and membrane fouling in a submerged flat-sheet membrane bioreactor, fed with synthetic wastewater, of similar composition to the effluents generated in a fish meal industry. After biomass acclimatization with saline conditions of 12 gNaCl/L and COD/N ratio of 15 in the bioreactor, results showed that the organic matter removal was higher than 90%, for all organic loading rates (0.8, 1, 1.33 and $2gCOD/L{\cdot}d$) and nitrogen loading rates (0.053, 0.067, 0.089 and $0.133gN/L{\cdot}d$) tested during the study. However, nitrification was only carried out with the lowest OLR ($0.8gCOD/L{\cdot}d$) and NLR ($0.053gN/L{\cdot}d$). An excessive concentration of organic matter in the wastewater appears as a limiting factor to this process' operating conditions, where nitrification values of 65% were reached, including nitrogen assimilation to produce biomass. The analysis of membrane fouling showed that the bio-cake formation at the membrane surface is the most impacting mechanism responsible of this phenomenon and it was demonstrated that organic and nitrogen loading rates variations affected membrane fouling rate.

• 한국농공학회논문집
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• 제60권5호
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• pp.55-67
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• 2018

The objectives of this study were to monitor organic farming upland compared with conventional upland field and to evaluate nutrient loads reduction of surface cover effect with long-term historical climate data. APEX(Agricultural Policy Environmental eXtender) model was validated with experimental data and used for assessing surface cover scenarios for 30-year simulation periods. The validated values of RMSE(Root Mean Square Error), RMAE(Root Mean Absolute Error), $R^2$ and E(Nash-Sutcliffe efficiency) for runoff were 1.17-1.37 mm/day, 0.28-0.45 mm/day, 0.88-0.90 and 0.82-0.94 in two treatments, respectively. Those for water quality (nitrogen) were 0.05-0.16 kg/ha, 0.52-0.75 kg/ha, 0.67-0.72 and 0.32-0.70 in two treatments, respectively, and therefore the validated model showed good agreement with the observed runoff and nitrogen load for the study period. When decreasing the surface cover rate of organic farming field to 75%, 50%, 25%, and 0% (conventional field), average annual runoff increased by 7%, 15%, 23% and 31%, respectively. Under same condition of decreasing the surface cover rate, average annual nitrogen loads increased by 1.4 times, 1.7 times, 2.0 times, and 2.3 times compared with organic farming field, respectively. This study showed that it is possible to present an appropriate surface cover ratio to maintain conventional production and minimize nonpoint sources pollution for organic farming system, although long-term monitoring is needed to determine its effects on environmental concerns, crop competition, and other uncertainty.

• 상하수도학회지
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• 제37권5호
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• pp.253-259
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• 2023

Bioreactors are devices used by sewage treatment plants to process sewage and which produce active sludge, and sediments separated by solid-liquid are treated in anaerobic digestion tanks. In anaerobic digestion tanks, the volume of active sludge deposits is reduced and biogas is produced. After dehydrating the digestive sludge generated after anaerobic digestion, anaerobic digested wastewater, which features a high concentration of organic matters, is generated. In this study, the decomposition of organic carbon and nitrogen was studied by advanced oxidation process. Ozone-microbubble flotation process was used for oxidation pretreatment. During ozonation, the TOC decreased by 11.6%. After ozone treatment, the TOC decreased and the removal rate reached 80.4% as a result of the Ultra Violet-Advanced Oxidation Process (UV-AOP). The results with regard to organic substances before and after treatment differed depending on the organic carbon index, such as CODMn, CODCr, and TOC. Those indexes did not change significantly in ozone treatment, but decreased significantly after the UV-AOP process as the linkage treatment, and were removed by up to 39.1%, 15.2%, and 80.4%, respectively. It was confirmed that biodegradability was improved according to the ratio of CODMn to TOC. As for the nitrogen component, the ammonia nitrogen component showed a level of 3.2×10² mg/L or more, and the content was maintained at 80% even after treatment. Since most of the contaminants are removed from the treated water and its transparency is high, this water can be utilized as a resource that contains high concentrations of nitrogen.

• 농업과학연구
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• 제49권4호
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• pp.657-666
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• 2022

Nitrogen (N) is a vital element in growing crops and is essential for improving the yield and quality of crops. Thus, N fertilizer is the most widely used fertilizer and the primary N input source in soil-crop systems. Inorganic fertilizers such as urea are known to improve crop productivity and increase soil fertility. However, application with excessive amounts can interfere with crop growth and accelerate soil acidification. For these reasons, the use of organic fertilizers, which mainly contain organic nitrogen, has gradually increased worldwide. Therefore, this study evaluated the effects of N fertilizer on the growth of Chinese cabbage including its functional compounds glucosinolates (GSLs). For the cultivation of Chinse cabbage, inorganic fertilizer was used for urea, and organic fertilizers were divided into conventional and biochar-based fertilizers. The growth parameters of Chinese cabbage treated by organic fertilizers was better than those of the inorganic fertilizers. Additionally, it was found that their co-application was more efficient. However, their GSL contents were lower with the application of the organic fertilizers. The characteristics of the experimental soil also changed according to the type, amounts and co-application of fertilizers. Therefore, this study presents the basis for an eco-friendly method that can increase the functionality and productivity of Chinese cabbage compared to conventional cultivations.

• Journal of Animal Science and Technology
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• 제62권1호
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• pp.74-83
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• 2020

Organic waste used as a feedstock in the anaerobic digestion (AD), it includes carbon and nitrogen. Carbon and nitrogen have an effect on the various digestive characteristics during AD, however, the study is rare about those of the interaction. This study investigates the influence of carbon type and carbon to nitrogens (C/N ratios) on the AD characteristics of organic waste. Experimental treatments involved a combination of three carbon types with three C/N ratios. The AD tests were carried out using a 125-mL serum bottle at a constant temperature of 37℃ and moisture 95% for 18 days. Degradation pattern shows the difference among three-carbon treatments, the starch group was faster than other groups. Maximum methane production date was similar between starch (9.96 ± 0.05 day) and xylan group (10.0 ± 0.52 day), those of the cellulose group (14.6 ± 1.80 day) was slower than other groups (p < 0.05). The lag phase was only affected by the carbon type (p < 0.05). Ammonia nitrogen was mainly affected by nitrogen concentration regardless of carbon type (p < 0.05). This study showed that xylan is useful as feedstock in order to decrease the lag phase, and it showed that ammonia was independently affected by the nitrogen concentration.

• 한국유기농업학회지
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• 제21권3호
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• pp.381-389
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• 2013

본 연구는 보리와 완두 혼파 포장에서 유기질소질 비료의 시용 수준이 건물생산성, 질소 고정 그리고 이동율 및 이동량을 측정하기 위하여 실시하였다. 처리는 유기질소 40kg, 80kg, 그리고 120kg/ha의 3처리와 질소고정 측정을 위해 대조구로 보리단파구를 각 처리마다 배치하였다. 난괴법 3처리 3반복으로 처리하여 3월부터 6월까지 재배하였다. 보리는 40kg/ha와 완두 80kg/ha를 파종 후 발아를 촉진하기 위하여 흑색 비닐을 멀칭하였다. 질소 고정을 측정하기 위하여 99.8원자% $15N(NH_4)_2SO_4$를 4월 15일 ha당 1kg 수준으로 증류수에 혼합하여 $30{\times}20cm$ 쿼드랏에 시용 하였다. 공중질소 고정율은 32.4%에서 0% 사이였다. 보리에서 완두에로의 질소 이동률은 차이법에서 47.6%에서 21.8% 사이 그리고 동위원소 희석액 처리법에서 24.6%와 21.4%를 나타냈다. 이동량은 차이법에서 92.8kg/ha에서 41.9kg/ha 및 49.7kg 반면 120kg N 유기질 시용구는 동위원소희석법에서는 질소이동이 일어나지 않은 것으로 나타났다. 결론적으로 유기질 비료의 증가에 따른 두과작물의 공중질소고정 향상, 화본과 작물로의 질소이동효과가 분명하지 않았다.

• 한국토양비료학회지
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• 제28권4호
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• pp.356-362
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• 1995

1979년 이래 유기물(有機物)을 연용(連用)한 논토양에 있어서 미생물상(微生物相)의 이절적(李節的) 변화(變化)를 구명(究明)하고자 호남지역 전북통인 논토양에 유기물(有機物)로써 무시용, 볏짚 및 퇴비를 그리고 질소수준으로써 무시용, 150kg/ha를 처리하여 표토(表土)로부터 15cm깊이토양의 미생물상(微生物相) 변화(變化)를 검토(檢討)하였다. 전세균수(全細菌數)는 수도이앙전(水稻移秧前)인 담수직후(湛水直後)부터 유수형성기(幼穗形成期)까지 점진적인 증가 후 수확기까지 감소(減少)하였으며 방선균(放線菌), 사상균(絲狀菌) 및 셀루로스분해균수(分解菌數)은 유수형성기(幼穗形成期)까지 미약한 변화를 보였으나 그 이후 수확기까지 증가(增加)하였다. 또한 대부분의 미생물수(微生物數)는 유기물과 질소의 장기혼용구(長期混用區)에서 높았으나 셀루로스분해균만은 유기물 단독시용구에서 높았다. 질소순환미생물중 암모니아 산화균수는 수확기에, 질산산화균수와 질산환원균수는 유수 형성기에 그리고 탈질균수는 분얼초기에 높았으나 암모니아 화성균수는 유기물 또는 질소(窒素)시용 여부에 따라 달랐다. 이들 미생물들은 유기물(有機物)이나 질소의 단독시용구에 비하여 유기물과 질소혼용구(窒素混用區)에서 높았으며, 특히 탈질균은 유기물(有機物)중 볏짚시용구에서 높았으나 그 외는 차이가 없었다.

• 한국유기농업학회지
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• 제5권1호
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• pp.87-99
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• 1996

Cultural conditions for mass production of the antagonistic bacteria, Bacillus subtills CAP134 against pathogens causing major airborne diseases to apple tree, effect of temperature, pH, carbon and nitrogen source in the culture broth were investigated. The bacterial growth was most vigorous when the temperature and pH of the culture broth was 30~$35^{\circ}$C, and 7, respectively. As for carbon source, dextrose was best followed in order by dextrose(monosaccharides)>sucrose(disaccharides)$\geq$saccharose(di-saccharides)>starch (polysaccharides). Among different sugars, bacterial growth was favored by in the order of brown, black and white sugars, indicating that the bacterial growth might be promoted by the minor elements presented as impurities in the less purified sugars. As for nitrogen source, organic forms were better to bacterial growth than inorganic forms, that is polypeptone was best followed in order by soy sauce, soybeen milk and inoganic nitrogens. Differences in bacterial growth among different forms of inorganic nitrogen were negligible.

• Journal of Microbiology and Biotechnology
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• 제15권6호
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• pp.1159-1163
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• 2005

The production of hydrogen by Chlamydomonas reinhardtii UTEX 90, a marine green alga, was performed under dark fermentation. The effects of initial nitrogen and phosphorus concentration on the cell growth and the production of hydrogen and organic substances were investigated. In the growth stage, the maximum dry cell weight (DCW) was 3 g/l when the initial ammonium concentration was 15 mM. In the dark fermentation, the maximum hydrogen production was $3.5\;{\mu}mol/\;mg$ DCW when the initial nitrogen concentration was 7.5 mM. The nitrogen concentration had a greater effect on organic compound and hydrogen production than the phosphorus concentration during the dark fermentation. An investigation of the duration of dark fermentation showed that, at least until three days, dark fermentation should be prolonged for maximum hydrogen production.

• 한국유기농업학회지
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• 제6권1호
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• pp.85-98
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• 1997

Cultural conditions for mass production of the antagonistic bacteria, Bacillus subtills CAP141 against pathogens causing major airborne diseases to apple trees, effects of temperature, pH, carbon and nitrogen source in the culture broth were investigated. The bacterial growth was most vigorous when the temperature and pH of the culture broth was 30~35$^{\circ}$C and 7, respectively. As for carbon source, dextrose was best followed in order by dextrose(monosaccharide) > sucrose(disaccharide) $\geq$ saccharose (market disaccharides) > starch (polysaccharieds). Among different sugars, bacterial growth was favored by in the order of brown, black and white supars, indicating that the bacterial growth might be promoted by the minor elements presented as impurities in the less purified sugars. As for nitrogen source, organic forms were better to bacterial growth than inorganic forms, that is polypeptone was best followed in order by soy sauce, soybeen milk and inorganic nitrogens. Differences in bacterial growth among different forms of inorganic nitrogen were negligible.