• Journal of the Korean Society for Marine Environment & Energy
• /
• v.10 no.1
• /
• pp.29-43
• /
• 2007

For effective management of water quality on the southern coast of korea, a three-dimensional eco-hydrodynamic model is used to predict water quality in summer and to estimate the reduction rate in pollutant loads that would be required to restore water quality. Under the current environmental conditions, in particular, pollutant loadings to the study area were very high, chemical oxygen demand (COD) exceeded seawater quality criteria to comply with current legislation, and water quality was in a eutrophic condition. Therefore, we estimated reduction rates of current pollutant loads by modeling. The model reproduced reasonably the flow field and water quality of the study area. If the terrestrial COD, inorganic nitrogen and phosphorus loads were reduced by 90%, the water quality criteria of Region A were still not satisfied. However, when the nutrient loads from polluted sediment and land were each reduced by 70% simultaneously, COD and $Chl-{\alpha}$ were restored. When we reduced the input COD and nutrient loads from the Nakdong River by 80%, $Chl-{\alpha}$ and COD of Region B decreased below $10\;{\mu}g\;1^{-1}$ and $2\;mg\;1^{-1}$, respectively. The water quality criteria of Region C were satisfied when we reduced the terrestrial COD and nutrient loads by 70%. Total allowable loadings of COD and inorganic nutrients in each region were determined by multiplying the reduction rates by current pollutant loads. Estimated high reduction rates, although difficult to achieve at the present time under the prevailing environmental conditions, suggest that water pollution is very severe in this study area, and pollutant loads must be reduced within total allowable loads by continuous and long-term management. To achieve the reduction in pollutant loads, sustainable countermeasures are necessary, including the expansion of sewage and wastewater facilities, polluted sediment control and limited land use.

• The Journal of the Korea Contents Association
• /
• v.9 no.8
• /
• pp.1-8
• /
• 2009

With the development of IT convergence technology and the construction of master plan for the four rivers restoration of the government, the importance of the eco-friendly water pollution management is being spotlighted. In this paper, we proposed the effective water pollution management using the reservoir tank automatic classification for improving the water quality and on-line managing efforts of ceo-friendly reservoir tanks. The proposed method defined the seven factors of water pollution evaluation and managed the water pollution according to hydrogen ion concentration(pH), chemical oxygen demand(COD), suspend solid(SS), dissolved oxygen(DO), count of coliform group(MPN), total phosphorus(T-P), and total nitrogen(T-N) using the sensors. We measured the values for the seven factors from the reservoir tank and normalized to ranging from 1 to 9. To evaluate the performance of the water pollution management using the reservoir tank automatic classification, we conducted F-measure so as to verify usefulness. This evaluation found that the difference of satisfaction by the traditional system was statistically meaningful.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.05a
• /
• pp.249-254
• /
• 2003

분석에 이용된 격자망은 동곡, 고로, 미성, 병천, 효령 및 무성지점에 각각 12개, 30개, 45개, 76개, 46개 및 1265개의 조격자를 구성하였으며 하천의 수로방향 및 경사형태를 세분화하기 위하여 각 지점에 대하여 8개, 24개, 24개, 44개, 12개 및 64개의 세격자로 분할하였다. AGNPS를 이용한 첨두유량의 모의발생 결과치가 동곡, 고로, 미성, 병천, 효령 및 무성지점에서 측정값과 비교하여 각 호우사상별로 상대오차가 1.0~25.0%, 4.0~27.0%, 7.0~29.2%, 2.0~23.9%, 3.0~25.0% 및 3.6~21.0%의 차이를 나타내었다. 분석결과에서 AMCII조건에서는 관측치와 분석결과치가 유사하게 나타났으나 AMCI조건에 대해서는 상대적으로 작은 값을 보였으며 AMCIII조건에서는 다소 큰 값으로 분석되었다. SCS방법에서 제안하는 AMC조건별 CN값을 우리 실정에 적합하도록 수정 보완하기 위한 수정 유출곡선지수 $CN_{m}$ /I과 $CN_{m}$/III을 재구성하였으며, 여기에 적용되는 수정 유출 곡선지수식의 계수 a를 추정한 결과, 기왕에 발표된 연구결과와 거의 일치된 경향을 나타내었다. 제안된 수정 CN식을 이용하여 산정한 결과치와 관측치는 거의 유사하게 나타났다. AGNPS모델에 의한 유출량 산정에 있어 수문학적 토양피복형수(CN)의 결정을 위하여 선행강우량과 토양의 공극율 및 지형인자인 각 셀마다의 유역경사를 이용하여 관계식(CN =f($X_1$, $X_2$, $X_3$))을 유도하였으며, 분석 결과에서 CN이 선행강우량과 가장 밀접한 관계가 있음을 알 수 있었으며 유역경사, 토양의 공극율 순으로 나타났다..88mg/$\ell$~의 범위로 나타났다. 무태교 지점에서의 총인의 농도는 0.52mg/$\ell$~0.99mg/$\ell$~의 범위이었다. 신천에 금호강물을 혼합한 이후에도 부유물질, 생화학적산소요구량, 암모니아태 질소, 총인 등의 농도가 개선되지 않았다. 즉 금호강물의 혼합은 신천수질환경사업소에서 배출되는 방류수에 함유되어 있을 2차 오염물질의 희석이라는 이점외의 수질개선효과는 확인되지 않았다.l years and a new type of transfer crane has been developed. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results co

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.34 no.5
• /
• pp.1477-1488
• /
• 2014

Prevalent construction of impermeable pavements in urban areas causes diverse water-related environmental issues, such as lowering ground water levels and shortage of water supply for the living. In order to resolve such problems, a rainwater reservoir can be an effective and useful solution. The rainwater reservoir facilitates the hydrologic cycle in urban areas by temporarily retaining precipitation-runoff within a shallow subsurface layer for later use in a dry season. However, in order to use the stored water of precipitation-runoff, non-point source pollutants mostly retained in initial rainfall should be removed before being stored in the reservoir. Therefore, the purification system to filter out the non-point source pollutants is essential for the rainwater reservoir. The conventional soil filtration technology is well known to be able to capture non-point source pollutants in a economical and efficient way. This study adopted a sand filter layer (SFL) as a non-point source pollutant removal system in the rainwater reservoir, and conducted a series of lab-scale chamber tests and field tests to evaluate the pollutant removal efficiency and applicability of SFL. During the laboratory chamber experiments, three types of SFL with the different grain size characteristics were compared in the chamber with a dimension of $20cm{\times}30cm{\times}60cm$. To evaluate performance of the reservoir systems, the concentration of the polluted water in terms of TSS (Total Suspended Solids) and COD (Chemical Oxygen Demand) were measured and compared. In addition, a reduction in hydraulic conductivity of SFL due to pollutant clogging was indirectly estimated. The optimum SFL selected through the laboratory chamber experiments was verified on the in-situ rainwater reservoir for field applicability.

• Korean Journal of Ecology and Environment
• /
• v.38 no.3 s.113
• /
• pp.372-381
• /
• 2005

This study was conducted to test the efficiency of water quality improvement using the dissolved air flotation (DAF) technique in a shallow eutrophic reservoir. The application of DAF was followed by the addition of a chemical coagulant (poly aluminum chloride; PAC). The experiment was conducted in the mesocosm scale (wide ${\times}$ length ${\times}$ depth: 6 m ${\times}$ 6 m ${\times}$ 3 m). Suspended solids (SS) and volatile SS (VSS) concentration decreased by 54 ${\sim}$ 71% and 57 ${\sim}$ 79% of the initial concentrations, respectively. Total phosphorus and Chl- a concentration also decreased by 74 ${\sim}$ 92% and 54 ${\sim}$ 98%, respectively. BOD decreased by>86% while COD decrease ranged 29 ${\sim}$ 63%. Dissolved inorganic P (DIP) and dissolved total P (DTP) concentration decreased by 34 ${\sim}$ 88% and 62 ${\sim}$ 88%, respectively. After DAF application further onto the sediment, DIP-release rates from the sediment decreased by 17% (0.82 ${\to}$ 0.68 mg $m^{-2}$$day^{-1}$ in the oxic condition and 23% (2.27 ${\to}$ 1.76 mg $m^{-2}$$day^{-1}$) in the anoxic condition, compared to the release rate from the untreated sediment. DTP-release rate from both the oxic and anoxic sediments also decreased by 33% (5.62 ${\to}$ 3.78 mg $m^{-2}$$day^{-1}$) and 20% (6.23 ${\to}$ 4.99 mg $m^{-2}$$day^{-1}$), respectively. These results suggest that the DAF application both to the water column and onto the sediment be effective to improve water quality by removing particulate matters in the water column as well as reducing P-release from the sediment.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.23 no.2
• /
• pp.36-46
• /
• 2015

Integration of crop-livestock farming has been a problem-solving mode for abatement of environmental pollution and recovery of resources in recent years. The objectives of this study were 1) to suggest the customized integration of crop-livestock farming model reflecting the regional characteristics through in-depth analysis of case study and 2) to analyze the livestock nutrients flow in terms of three primary elements as nitrogen(N), phosphorous(P), and potassium(K). The personal interview and survey were carried out in 2012 for a total of 161 farms from four different regions(NS, NW, JJ, YC) in South Korea. The mass balance analysis was used to suggest and evaluate the models for two sites(JJ and YC). The results showed that NS and NW sites produced relatively more livestock manure than the sites of YC and JJ because of the regional differences in livestock numbers and urbanization. The models were suggested for the site JJ and site YC, and 'two track model(energy and resource recovery)' and 'dispersal type model' were assigned respectively. For the nutrient flows, the releasing P and K with new models had increased up to 7%, while N release had decreased down to 15% in both YC and JJ sites compared to the present treatment system. Estimated value showed that there was oversupply of N (719 ton/yr) and $P_2O_5$ (1,269 ton/yr) in YC and deficiency of N (671 ton/yr) and excessive $P_2O_5$ (32 ton/yr) in JJ respectively. Therefore, P runoff has to be considered an eutrophication occurs in rural small stream when an integration of crop-livestock farm system is applied into both sites.

• Clean Technology
• /
• v.9 no.2
• /
• pp.49-55
• /
• 2003

The generation of livestock wastewater in Korea amounts to $130,000m^3/day$, 0.43% of the total waste water volume, but which corresponds to 8.6% of total BOD loading. Furthermore this wastewater contains a large amount of nitrogen and phosphorus that are major causes of eutrophication in rivers and lakes. The average volume of livestock wastewater in a Korea's single farm is only $2.5m^3/day$, which necessitates development of a simple and economical process for the removal of nitrogen and phosphorus. Introduction of filtration method removes more than 90% of suspended solids. Subsequent application of reverse osmosis removes more then 95% of total nitrogen and phosphorus in the wastewater. The effluent of this treatment will yield less than 200 mg/L of total nitrogen and 1 mg/L of total phosphorous, which are lower than 260 mg/L of total N and 50 mg/L of total P, the regulation values of Ministry of Environment, Korea. Treating $2m^3/day$ of livestock wastewater was found to be feasible with the application of filtration and reverse osmosis and the electricity requirement was estimated to be about 30 Kwh/month.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2003.05a
• /
• pp.292-296
• /
• 2003

Autoclaving처리를 하지 않은 키토산과 autoclaving처리한 키토산과의 중금속 흡착실험을 해 본 결과 다음과 같은 결과를 도출 할 수 있었다. 1) 먼저 중금속간의 흡착능을 고찰하기 위하여 Langmuir와 Freundlich 흉착등온식에 적용시켜 본 결과 Freundlich 흡착등온식 보다는 Langmuir 흡착등온식이 보다 적합한 것으로 나타났다. 2) 시간에 따라서 autoclaving 처리한 키토산의 중금속 제거 가능성과 그 효율을 검토하기 위하여 각 중금속간의 Langmuir 흡착등온식을 이용하여 $q_{max}$를 나타냈다. 15 min > 60 min > 0 min 순으로 모든 중금속 제거 실험에서 15 min 동안 autoclaving 처리한 키토산의 중금속 흡착량이 가장 높은 것으로 나왔다. 그러므로 기존의 키토산 보다는 15 min동안 autoclaving 처리한 키토산이 중금속 제거에 더 좋은 흡착제로써 역할을 할 수 있을 것으로 판단된다. 3) 키토산을 이용한 중금속 제거에서는 $Pb^{2+}$ > $Cd^{2+}$ > $Cu^{2+}$ > $Cr^{3+}$순서로 제거가 되었다. 여러 연구자들의 실험 결과를 종합해 볼 때 Pb$^{2+}$가 중금속 중에 제거가 잘 된다는 연구 결과가 많이 발표 되었으며, $Cd^{2+}$, $Cu^{2+}$, $Cr^{3+}$의 경우에는 흡착제의 종류에 따라서 제거되는 순서가 다르다는 연구 결과들이 보고 되고 있다. 그러나 어떠한 이유로 중금속의 제거에 차이가 있는지에 대해서는 명확한 결론이 내려져 있지 않는 실정이다. 이러한 중금속간의 경쟁적인 관계에 대해 더 많은 세밀한 연구가 이루어져야 할 것 같다.는 0.52mg/$\ell$~0.99mg/$\ell$~의 범위이었다. 신천에 금호강물을 혼합한 이후에도 부유물질, 생화학적산소요구량, 암모니아태 질소, 총인 등의 농도가 개선되지 않았다. 즉 금호강물의 혼합은 신천수질환경사업소에서 배출되는 방류수에 함유되어 있을 2차 오염물질의 희석이라는 이점외의 수질개선효과는 확인되지 않았다.l years and a new type of transfer crane has been developed. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. On the basis of the simplified model, the simulation was performed and the results could be confirmed by the experiments under various conditions.뢰, 결속 등 다차원의 개념에 대한 심도 깊은 연구와 최근 제기되고 있는 이론

• Food Science and Preservation
• /
• v.20 no.2
• /
• pp.265-271
• /
• 2013

The objective of this study was to assess the quality characteristics of yanggaeng prepared with different ratios of blueberry powder: 0%, 3%, 6%, and 9%. The moisture content of the control yanggaeng was lower than that of any other blueberry added groups. The pH decreased while the titratable acidity and the Brix increased as the amount of blueberry powder increased. The lightness (L) and yellowness (b) were the highest while the redness (a) was the lowest in the controls. Texture profile analysis showed that the hardness of the added groups were higher than that of the control which were the lowest. The total polyphenol content and DPPH (2,2-diphenyl-1-picrylhydrazyl) radical scavenging activity increased as the amount of blueberry powder increased. The results of consumer acceptance test revealed that the color preference was the highest in the 9% added group while the smell, taste, texture and the overall acceptability showed no significant differences groups. Based on these results, it is suggested that yanggaeng with up to 9% added blueberry powder can be developed as products without adverse effects on sensory characteristics.

• Tunnel and Underground Space
• /
• v.28 no.6
• /
• pp.609-619
• /
• 2018

This study was carried out at a local limestone mine to analyze the ventilation efficiency of the shaft equipped with a main fan. The results show that its ventilation efficiency is clearly verified for the natural as well as the mechanical ventilation. The airflow rate of $11.7m^3/s$ was induced by the natural ventilation force and the maximum quantity is almost same as the airflow rate estimated by monitoring the average temperatures in the upcast and downcast air columns. Meanwhile, the airflow rate exhausted by the main fan through the shaft was $20.3{\sim}24.8m^3/s$; variation of the quantity was caused by the upward shift of the mine ventilation characteristic curve due to the frequent movement of the equipment. This indicates efforts are required to reduce the ventilation resistance and raise the quantity supplied by the main fan. The turbulent diffusion coefficients along the 1912 m long airway from the portal to the shaft bottom was estimated to be $15m^2/s$ and $18m^2/s$. Since these higher coefficients imply that contaminants will be dispersed at a faster velocity than the airflow, prompt exhaust method should be planned for the effective air quality control. The ventilation shaft and main fan are definitely what local limestone mines inevitably need for better working environment and sustainable development.