• Proceedings of the Korea Water Resources Association Conference
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• 2015.05a
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• pp.425-425
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• 2015

본 연구는 밭에서 발생하는 비점오염원의 저감 효과를 분석하기 위하여 최적관리기법(BMPs) 중 경운방법과 침투짚단을 하여 효과를 분석하고자 하였다. 시험포 1개의 면적은 $150m^2$ (폭 5 m, 경사장 30 m)이며, 모두 사질토의 특성을 가진 토양이다. 시험포는 총 8개(경사도 3% 4개, 8% 4개)로 각각 무경운 시험포 2개와 경운 시험포 1개 그리고 침투 짚단을 설치한 경운 시험포 1개로 경사도와 영농방법을 다르게 조성하였다. 실험의 오차를 줄이기 위하여 강우지속시간과 강우량 그리고 강우강도가 일정한 인공강우 실험을 수행하였으며, 실험시 바람에 의한 강우량의 오차를 줄이기 위해 날씨가 맑은 날에 실시하였다. 또한, 선행무강우일수 7일로 유지하여 토양의 함수비를 동일한 조건이 되도록 하였다. 총 3회의 인공강우실험에서 강우강도는 30 mm/hr 이였으며, 강우로 인해 발생한 유출수는 수위를 측정한 뒤, 수위-유량곡선식을 이용하여 유량으로 환산하였으며, 이때 수질시료를 채취하였다. 채취된 수질시료는 $BOD_5$, $COD_{Cr}$, $COD_{Mn}$, TN, TP, DOC 등의 6개 항목을 분석하였다. 연구결과 경사도 3%의 침투짚단 시험포에서 오염부하는 경운 시험포 대비 $BOD_5$는 25.4%, $COD_{Cr}$은 20.5%, $COD_{Mn}$은 2.1%, DOC는 40.8%, 영양염류인 TN과 TP는 각각 23%와 8.7%가 저감되는 것으로 나타났다. 또한 경사도 3%의 무경운 시험포에서 오염부하는 경운 시험포 대비 $BOD_5$는 57.5%, $COD_{Cr}$은 59.8%, $COD_{Mn}$은 65%, TN과 TP는 65.4%와 75%로 저감되었다. 그리고 경사도 8%에서 경운 시험포대비 침투짚단 시험포의 오염부하는 $BOD_5$ 19.6%, $COD_{Cr}$과 $COD_{Mn}$은 각각 7.8%와 10% 그리고 영양염류인 TN은 15.5%, TP는 11.2%가 저감되는 것으로 나타났다. 경사도 8%에서 무경운 시험포에서는 경운 시험포 대비 $BOD_5$ 70.9%, $COD_{Cr}$과 $COD_{Mn}$은 각각 74.9%와 81.3% 그리고 영양염류인 TN은 70.2%, TP는 70.1%가 저감된 것으로 나타났다. 본 연구결과와 같이 경운을 하는 관행방법에 비해 토양의 침투능이 유지할 수 있는 무경운 방법이나 침투짚단을 활용하는 방법이 밭에서 발생하는 비점오염원을 저감할 수 있는 것으로 나타났다. 그러나, 본 연구의 결과는 3번의 인공강우 실험을 통해 분석된 결과로써 추가적인 연구를 통해 다양한 경사도와 영농방법에 따른 비점오염물질의 저감효과를 분석해야 할 것으로 보여진다.

• Journal of Korea Water Resources Association
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• v.52 no.3
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• pp.207-217
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• 2019

This study aims at development and application of a facility that is capable of reducing pollution in water quality by reducing nonpoint source pollutants (NPSP). NPSP originated from the initial rainfall caused not only large catchment of urban area pass a river but also small watershed pass a stream. For this purpose, the performance tests carried out with the field models from the facility based on the preceding study. And the tests induced reduction efficiency of biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (T-N) and suspended solid (SS), respectively. The average reduction efficiency obtained by time interval, and the result showed an excellent reduction performance. As a result, the facility satisfied reduction efficiency of NPSP of the proposed standard by the National Institute of Environmental Research, and thus it can be used in practical applications.

• Korean Journal of Ecology and Environment
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• v.45 no.1
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• pp.62-71
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• 2012

Lake Doam watershed was surveyed to evaluate non-point source discharge characteristics and discharge load including several water quality parameters in Song Stream from July 2009 to July 2011. Concentrations of water pollutants were high during the rainfall period, especially, SS, TP and COD showed increasing tendencies toward cumulative water discharge but TN did not show much difference. SS, TP and COD had an initial flush effect of over 50 mm rainfall event but there was no clear tendency for rainfalls below that level. Event mean concentration (EMC) regarding the rainy and dry period showed large differences. Especially rainy season EMC (SS, TP, COD) demonstrated an increasingly high tendency. EMCs of COD, SS, TN and TP measured for twelve rain events were as high as 26.1, 866.0, 4.68 and 0.605 mg $L^{-1}$, respectively. COD, SS, TN and TP loadings from the highland agricultural region of the Song Stream watershed were 34,263, 1,250,254, 2,673 and 933 kg $yr^{-1}\;km^{-2}$, respectively, which were relatively higher than the results of other stream systems. Therefore, it is strongly recommended that long-term monitoring and non-point pollution reduction programs for the highland agricultural area to continue. Furthermore, this non-point source pollution loading research acquired from the highland agricultural area could be the base for reassessment.

• Journal of Wetlands Research
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• v.9 no.2
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• pp.71-84
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• 2007

Masan Bay is a representative semi-closed bay acted as a sedimentation reservoir with a slow current velocity and a poor water circulation in Korea. The pollutants from terrestrial sources into the Masan Bay have apparently environmental pollution problems, such as eutrophication, red tied, and hypoxia. In this study, An ecological modeling work was performed to estimate the material circulation including the growth of bivalve in ecosystem. Furthermore, the effect of water purification was calculated by filter feeding bivalve to particulate organic matter just like COD and phytoplankton. And Water quality management strategy by bio-purification of bivalve is derived through selection of location, quantification of bivalve aquaculture farm. The results showed that the optimum location for bivalve farming is where phytoplankton accumulation by physical processes is maximized and the optimum density and area of bivalve are 35 individuals $m^{-3}$ and ca. 500 hectare, respectively. When assuming conditions for the optimum growth of bivalve, COD could decrease by up to 18% even without other reduction of pollution loads.

• Journal of Korean Society on Water Environment
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• v.28 no.6
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• pp.917-922
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• 2012

In order to improve applicability of a microbial fuel cell the laboratory-scaled study has been performed by adopting an air-cathode MFC system with high concentrated anaerobic slugies in this study. The concentrations of microbes are grouped into three types, Type A (TS 1.7%), Type B (TS 1.1%) and Type C (TS 0.51%). The open circuit voltage $(V_{oc})$ characteristics showed that the medium microbes concentration of 1.10% (Type B) kept a constant voltage of 1.0 V for 150 hours, which showed the longest time among three types (Type A and Type C). The discharge charge curves for a closed circuit with $500 \Omega$ also showed that Type B generated a stable discharge voltage of 0.8 V for a longer time as in the open circuit voltage case. This could be explained by the relatively large amount of the attached microbes. Under the $V_{oc}$condition the COD removal efficiency of Type B was found to be low for a long time, but those of Type A and C were found to be high for a short period of time. Therefore, the suspended microbes could decrease the coulombic efficiency. It was concluded that the high $V_{oc}$ was caused by low COD and the $V_{oc}$ became low after the COD removal. The COD reduction resulted in an unstable and low working voltage. From the polarization characteristics Type A was found to show the highest power density of $193\;mW/m^2$ with a fill factor of 0.127 due to the relatively high remaining COD even after the MFC reaction.

• Journal of Wetlands Research
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• v.19 no.3
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• pp.259-270
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• 2017

In this study, field-scale half-saturated bio-filter wetland equipped with recirculation system was operated with stormwater from the paved road, and its operational performance and functions of LID-BMP were analyzed and compared with other facilities. The reduction of TSS, COD, TN, and TP were 92%, 63%, 36%, and 75%, respectively. Comparison of the reduction efficiency were carried out with respect to ratio between surface and catchment areas(SA/CA). In addition, this LID-BMP facility can reduce about 70% of pollutant by treating only 18% of total rainfall runoff. The results show that LID used for this study gave similar efficiency although its ratio was smaller. In addition, comparison study was made between synthetic fiber as a filter media and organic media, which shows that there was not any significant difference between, TSS and TP reduction, but there were large difference in COD and TN removal due to the presence and absence of release of organic carbon. Meanwhile, wetland system in this study equipped with a first-flush capture gave a higher stability in terms of treatment performance.

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

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.2
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• pp.99-104
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• 2010

The purpose of this study is to develop Sewage Treatment Plant that treat sewage which occurred in ship using fixed media method and to consider applicable to the Pilot Scale device of the STP regulations in MLTM(Ministry of Land, Transport and Maritime Affairs) and MEPC(Marine Environment Protection Committee). In test results, pH geometric mean was 7.68, $BOD_5$(Biochemical Oxygen Demand) geometric mean was 7.28 mg/l, $COD_{cr}$(Chemical Oxygen Demand) geometric mean was 48.39 mg/l, TSS(Total Suspended Solid) geometric mean was 18.00/l, Residual chlorine geometric mean was 0.19 mg/l, and E. coli geometric mean was 1CFU/100 ml. In addition, about 97.4% of $BOD_5$ was reduced, the $COD_{cr}$ reduction averaged 96.4%and the TSS reduction averaged 97.6%. STP have been determined by the MLTM and MEPC regulation of the marine pollution prevention equipment for performance testing product.

• Korean Journal of Ecology and Environment
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• v.46 no.1
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• pp.128-134
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• 2013

In the summer season (June~August) during the study period of Lake Doam, average concentrations of major water quality parameters, COD, SS, TN, and TP were 4.0, 16.2, 3.129 and $0.077mg\;L^{-1}$, respectively, and Chl-a was $11.8mg\;m^{-3}$. The result has indicated that Lake Doam was a meso-eutrotrophic lake. Lake Doam data from the summer season (June~August), precipitation from 2001 to 2012, and water quality (COD, SS, TN, TP, Chl-a etc.) of seven years (2001, 2002, 2004 and 2009~2012), were statistically analyzed for long-term trends by Mann-Kendall test and Sen's slope estimator methods. The statistical results showed that precipitation, SD, COD, TN, $NO_3-N$, $NH_3-N$ and Chl-a had decreasing trends, and EC, turbidity, SS, TP and DIP had increasing trends. Suspended solids and total phosphorus were directly affected by precipitation. In the case of suspended solids, more aggressive and constructive plans need to be implemented than the current turbidity reduction project to achieve the targeted water quality ($5mg\;L^{-1}$ of SS) in Lake Doam. In particular, we need to specify a project that considers the steep topographic characteristics of high, land farming areas and precipitation conditions of the Lake Doam watershed, which can increase the efficiency of a turbidity reduction project.

• Journal of Environmental Science International
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• v.20 no.5
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• pp.647-653
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• 2011

Sediment cell is renewable energy which produces electric energy using immanent ingredients or reducing power of marine sediment as natural resources. Also the cell has an advantage that environmental pollution can be reduced through conversion of organic and inorganic contaminants into inert matter with generation of the energy. In this paper, we compared characteristics of electricity generation of the two different sediment cells, and investigated the regeneration effect of the sediment cells with manipulation of the sediment such as mixing and re-positioning. The results showed that 14.1 $W/m^2$ of power was obtained with the aluminum electrode, and the mixing of the sediment could increase the power by 4 $W/m^2$ compared to the control. Also, mixing the sediment has kept electricity for 4 weeks at a relatively constant level, which implied 'fuel regeneration effect'. Meanwhile, the sediment cell was proved to be effective in reduction of COD, which was up to 28.6%.