• Journal of Korean Society on Water Environment
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• v.27 no.3
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• pp.342-348
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• 2011

A hydrodynamic separator using natural free energy provided by bridge was operated for the treatment of stormwater runoff. The separator was automatically controlled by using electronic valve which is connected with pressure meter. Normally the separator was opened during dry days, but it was closed after the capture of first flush. The results indicated that the average pressure and the flow rate were directly affected by the rainfall intensity. The pressure was more than 3 meters as the rainfall intensity was above 5 mm/hr. The percent volume of underflow decreased as the pressure and flow rate increased, but the percent volume of overflow showed an opposite behavior. The concentration of total suspended solids (TSS) in underflow increased as a function of increasing pressure while it decreased in overflow. The TSS separation efficiency was evaluated based on mass balance. It ranged from 30% to 90% with the pressure ranging from 2 to 10 meters, and it was proportional to pressure and flow rate. The analysis of water balance indicated that around 13% of total runoff was captured by the separator as a first flush, and this runoff was separated as underflow and overflow with the respective percent volume of 29% and 71%. The pollutants budget was also examined based on mass balance. The results showed that the percent of TSS, $COD_{cr}$, TN and TP in underflow were 73%, 59%, 7.6% and 49%, respectively.

• Journal of Environmental Science International
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• v.16 no.5
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• pp.571-581
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• 2007

The mechanism of water pollution in Lake Shihwa, one of highly eutrophicated artificial lakes in Korea, has been studied using a numerical 3D physical-biochemical coupled model. In this study, the model was applied to estimate the contribution of land-based pollutant load to water quality of heavily polluted Lake Shihwa. The chemical oxygen demand(COD) was adopted as an index of the lake water quality, and the spatial distribution of an average COD concentration during the summer from 1999 to 2000 was simulated by the model. The simulated COD showed a good agreement with the observed data. According to reproducibility of COD, the high-est levels between 8 and 9 mg/L were shown at the inner site of the lake with inflow of many rivers and ditches, while the lowest was found to be about 5 mg/L at the southwestern site near to dike gate. In the pre-diction of water quality of Lake Shihwa, COD showed still higher levels than 3 mg/L in case of reduction of 95% for land-based pollutant load. This suggests that the curtailment of land-based pollutant load is not only sufficient but the improvement of sediment quality or the increase of seawater exchange should be considered together to improve a water quality in Lake Shihwa.

• Korean Journal of Ecology and Environment
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• v.33 no.3 s.91
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• pp.295-303
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• 2000

The water clarification efficiency was examined in a shallow wetland where dense vegetation was formed naturally in an abandoned paddy field. And, also two enclosure experiments were carried out to measure the effects of materials exchange between sediment and the overlying water with the existence of vegetation and accumulated litter. The hydraulic retention time of wetland was regulated in 1.2 day. The removal rates of SS (56%) and $NO_3-N$ (61%) were high, considering its short retention time. However, removal efficiencies of VSS (28%), COD (14%), DOC (1%),and TP (0.2%) were relatively lower. This low removal efficiencies were thought to be due to the release of dissolved form of organic matter and phosphorus from the sediment. Most of constituents except nitrate were higher in the enclosure at the beginning of enclosure installation than that of the outflowing water from wetland. And then, it has fluctuated and decreased with time. The wetland was in equilibrium state of settling, accumulation of organic debris, and regeneration of dissolved material from sediment. So ultimately high primary production by dense vegetation in the wetland may be the reason of unfavorable or low treatment efficiency of wetland after many years of operation for wastewater treatment. However, the water quality of effluent from the wetland showed smaller variation and better condition than that of inflow, especially during storm events. It can be concluded that this wetland is suitable for the improvement of water quality from nonpoint sources.

• Korean Journal of Soil Science and Fertilizer
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• v.44 no.5
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• pp.929-936
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• 2011

To treat non-point source pollution in Dongbok lake, removal efficiencies of pollutants were investigated in Dongbokcheon constructed wetlands (CWs) at different treatment time and wastewater loading. The wetlands consisted of forebay, wetlands ($1^{st}$, $2^{nd}$, $3^{rd}$, $4^{th}$, $5^{th}$, $6^{th}$, $7^{th}$, and $8^{th}$ wetlands) and sedimentation pond. The concentrations of BOD, SS, T-N, and T-P in inflow ranged $0.85{\sim}3.14mg\;L^{-1}$, $3.33{\sim}9.70mg\;L^{-1}$, $0.64{\sim}5.33mg\;L^{-1}$, and $0.03{\sim}0.10mg\;L^{-1}$ from April to October in 2008, respectively. The removal rates of BOD, SS, T-N, and T-P in Dongbokcheon CWs were 34%, 5%, 31%, and 13%, respectively. The removal rates of BOD and T-N were higher than those for SS and T-P. The amounts of pollutant removal in Dongbokcheon CWs were higher in the order of forebay > wetlands > sedimentation pond for BOD, sedimentation pond > wetlands > forebay for SS, sedimentation pond > forebay > wetlands for T-N. The amount of T-P removal in wetlands was higher than forebay and sedimentation pond.

• Journal of Soil and Groundwater Environment
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• v.11 no.4
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• pp.33-40
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• 2006

Residual pesticides discharged from diffuse sources at agricultural area in association with suspended solid will be settled at downstream, and may degrade surface water quality. This research studied dechlorination kinetic of atrazine, one of triazine-category herbicide, using zero-valent iron (ZVI) in sediment. It can be observed from the experiments that buffer capacity of sediment helped pH maintained beutral, resulted in continuous dechlorination. Sediments were spiked with atrazine at 10, 30, and 50 mg atrazine/L of total sediment for batch experiments. Dechlorination constants were $1.38x10^{-1}/d$ for the initial concentration of 10 mg/L, $1.29x10^{-l}/d$ for 30 mg/L, and $7.43x10^{-2}/d$ for 50 mg/L while dechlorination constants of initial concentration of 50 mg/L without ZVI adding were estimated as $3.05x10^{-2}/d. Half lifes atrazine by ZVI were estimated as 5.03 d fur 10 mg/L, 5.38 d for 30 mg/L, and 9.33 d for 50 mg/L, respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.454-459
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• 2008

하천의 건강성을 유지하고 수환경의 정상적인 기능을 회복하기 위해서는 수서생물들에게 알맞은 서식환경 조성, 점오염원 및 비점오염원 차단, 적절한 유량과 같은 다양한 조건이 요구된다(Gore 1895; Gore et al. 1989). 이 중 유량은 수생태계를 이루는 물리적, 화학적, 생물학적 요소들 가운데 기본이 된다고 할 수 있다(Bunn and Arthington 2002; Nilsson and Svedmark 2002; Arthington et al. 2006). 국내 하천관리를 위한 하천유지유량의 산정에서 고려하고 있는 갈수량, 하천생태계, 하천수질 등 8가지 항목 가운데 최근 생태계와 환경에 대한 사회적 국민적 관심이 증가하면서 하천생태계를 고려한 환경유량의 중요성이 부각되었으나, 현실적으로 생태계를 고려한 정량적 조사자료 구축 및 환경유량산정 등의 객관적 자료는 미흡한 실정이다. 특히, 과거 해당수계 및 하천의 어류분포 현황 파악을 중심으로 이루어진 어류조사는 환경유량 산정 시 기초자료로 활용하거나 직 간접적으로 어류상이 변화하는 원인을 분석하는 자료로 활용하기에는 객관성이 결여되어 있다고 할 수 있다. 어류모니터링 기법 확립은 환경유량산정에 있어 요구되는 정량화와 자료의 객관성을 높이기 위한 작업으로 문헌조사와 청문조사를 포함한 사전조사, 현장조사, 조사결과 정리, 고찰 등의 총 4가지 과정을 기본으로 실시하는 것으로 정하였다(그림. 1), 청문조사와 문헌조사 등의 사전조사를 통해 기존자료를 확보하고 현장의 답사, 조사구간, 방법, 시기 등의 선정을 통해 두 번째 단계인 현장조사의 효율성을 높였다. 현장조사에서는 어류분포 현황 외에도 해당지점의 하상재료, 식생, 유속, 수심, 수질 등 조사지점의 수 환경요소 전반을 기록하여 어류의 서식과 물리 화학적 수환경과의 상호관계를 파악하고자 하였다. 마지막으로 고찰단계에서는 조사 대상 지역 전반적인 어류상 특징과 함께 보호종, 한국고유종, 외래도입종 출현유무 및 빈도, 물리적, 화학적 수환경의 특징, 수환경에 따른 어류상 특징 등의 분석과 함께 조사하천의 건강성을 평가하고자 하였다. 본 연구는 어류모니터링 기법 확립을 통해 환경유량산정 시 요구되는 객관적 기초자료를 구축하고 나아가 오염물질 유입, 하천정비사업 등의 각종 교란요인에 의해 발생할 수 있는 문제점들에 능등적으로 대처하고 교란에 의해 악화된 수환경의 복원을 위해 요구되는 객관적 기초자료 생산에 목적이 있다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.30 no.1
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• pp.58-64
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• 2024

Approximately 250 marine oil spill accidents have occurred in Korea, with profound impact on local communities and the environment. The restoration process necessitates significant resources and costs to return affected areas to their pre-accident state. In accordance with the polluter pays principle, compensation is demanded from polluter, as stipulated in both international conventions and national laws. Consequently, investigations are conducted to determine civil and criminal liability. As the importance of investigation actors in oil spill accidents increases, standards such as CEN 15522-2 and ASTM D 3248 are employed to determine the similarity between the spilled oil and the oil of the suspected ship. Among these standards, CEN 15522-2, the most actively used European standard, underwent its third revision and is now known as EN 15522-2, as of 2023. This study used EN 15522-2 to analyze samples from marine oil spill accidents that occurred in Korea. The results indicated that, considering the characteristics of domestic spills where light fuel oil spills account for more than 40%, the application of EN 15522-2, which includes low-boiling point substances such as Adamantanes, was confirmed to be highly effective.

• Journal of the Korea Organic Resources Recycling Association
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• v.22 no.4
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• pp.21-27
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• 2014

Pig slurry has been considered as environmental waste to be treated in an appropriate manner. Moreover, water-born pollution loads by agricultural non-point source(NPS) pollution are expected to become intensified due to ongoing precipitation change. This study was conducted to develop a best management practice to reduce NPS pollution load by agricultural activity with pig manure compost. An eco-friendly way, small drainage pond, was suggested in this study to avoid direct drainage of agricultural runoffs and eventually reduce the amount of pollutants discharged into the surrounding aqua-environment. A small pond($12m^2$) was constructed at the corner of a rice paddy field($17,15m^2$) located in Suwon, Korea. Water was allowed to drain only via a small drainage pond. Sampling was repeatedly made at two locations, one from an entrance and the other from an exit of a pond, during the rice cultivation period(May to October, 2013). Generally, sampling was made only when runoff water drained through a pond, such as during and/or after rain(irrigation). The water quality analysis showed that all quality parameters(SS, $COD_{Mn}$, T-N, and T-P) were improved as water passed through the pond. The amount of runoff water was reduced by 67.8%. Suspended solids and $COD_{Mn}$ concentrations were reduced by 79.8% and 71.9%, respectively. In case of T-N and T-P amounts, the reduction rates were 73.6% and 74.9%, respectively. Our data implies that agricultural NPS pollution from rice paddy fields with pig manure-based fertilizer can be effectively managed when an appropriate drainage water management practice is imposed.

• Journal of the Korean Institute of Landscape Architecture
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• v.48 no.1
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• pp.25-34
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• 2020

Land use in watersheds has been shown to be a major driving factor in determining the status of the water quality of streams. In this light, scientists have been investigating the roles of riparian vegetation on the relationships between land use in watersheds and the associated stream water quality. Numerous studies reported that riparian vegetation could alleviate the adverse effects caused by land use in watersheds and on stream water quality through various hydrological, biochemical and ecological mechanisms. However, this concept has been criticized as the true effects of riparian vegetation must be assessed by comprehensive models that mimic real environmental settings. This study aimed to estimate a comprehensive structural equation model integrating topography, land use, and characteristics of riparian vegetation. We used water quality data from the Nakdong River system monitored under the National Aquatic Ecosystem Monitoring Program (NAEMP) of the Korean Ministry of Environment (MOE). Also, riparian vegetation data and land use data were extracted from the Land Use/Land Cover map (LULC) produced by the MOE. The number of structural equation models (SEMs) were estimated in Amos of IBM SPSS. Study results revealed that land use was determined by elevation, and developed areas within a watershed significantly increased the concentration of Total Nitrogen (TN) in streams and LDI in riparian vegetation. On the contrary, developed areas significantly reduced LPI and PLAND. At the same time, PLAND and LDI significantly reduced the concentration of TN in streams. Thus, it was clear that developed areas in watersheds had both a direct and an indirect impact on the concentration of TN in streams, and spatial pattern and the amount of vegetation of riparian vegetation could significantly alleviate the negative impacts of developed areas on TN concentration in streams. To enhance stream water quality, reducing developed areas in a watershed is critical for long-term watershed management plans, restoration patterns for riparian vegetation could be immediately implemented since riparian areas were less developed than most other watersheds.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.4
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• pp.642-648
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• 2012

To evaluate the water quality in Juksancheon constructed wetlands for treating non-point source pollution, the removal rates of nutrients in water and the total amounts of T-N and T-P uptakes by water plants were investigated. Chemical characteristics of T-N and T-P in sediment were investigated. The concentrations of BOD (Biochemical Oxygen Demand), COD (Chemical Oxygen Demand), SS (Suspended Solids), T-N and T-P in inflow were 0.07~1.47, 0.60~2.65, 0.50~4.60, 1.38~6.26 and $0.08{\sim}0.32mg\;L^{-1}$, respectively. The removal rates of BOD, COD, SS, T-N, and T-P were -10, 51, 66, -3 and 5%, respectively. The maximum amount of T-N uptake by water plants in August was $368.7mg\;plant^{-1}$ in the $2^{nd}$ treatment stage by Nymphoides peltata, $1314.6mg\;plant^{-1}$ in the $3^{rd}$ treatment stage by Iris pseudacorus, $1160.4mg\;plant^{-1}$ in the $4^{th}$ treatment stage by Nymphaea tetragona GEORGI, respectively. The maximum amount of T-P uptake by water plants in August was $121.7mg\;plant^{-1}$ by Nymphoides peltata in the $2^{nd}$ treatment stage, $268.7mg\;plant^{-1}$ by Iris pseudacorus in the $3^{rd}$ treatment stage and $212.0mg\;plant^{-1}$ by Nymphaea tetragona GEORGI in the $4^{th}$ treatment stage, respectively. Organic matter contents in sediments were not different. Contents of T-N and T-P in sediments were higher in spring. Microbial biomass C:N:P ratios in sediments in spring, summer, autumn and winter were 117~140:1~4:1, 86~126:5~6:1, 68~101:2~6:1 and 47~138:2~4:1, respectively. We could conclude that Juksancheon constructed wetlands show high removal efficiencies of COD and SS. However, improvements of management in winter season should be considered to improve the removal efficiencies of pollutants.