• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.3
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• pp.91-104
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• 2013

The objectives of this study were to monitor and assess the environmental impacts of indirect wastewater reuse on water quality and soil in paddy fields. Yongin monitoring site (YI) irrigated from agricultural reservoir and Osan monitoring site (OS) irrigated with treated wastewater diluted with stream water were selected as control and treatment, respectively. Monitoring results for irrigation water quality showed a significant statistical difference in salinity, exchangeable cation and nutrients. Pond water quality showed a similar tendency with irrigation water except for the decreased difference in nutrients due to the fertilization impact. Soil chemical properties mainly influenced by fertilization activity such as T-N, T-P, and $P_2O_5$ were changed similarly in soil profiles of both monitoring sites, while the properties, EC, Ca, Mg, and Na, mainly effected by irrigation water quality showed a considerable change with time and soil depth in treatment plots. Heavy metal contents in paddy soil of both control and treatment did not exceed the soil contamination warning standards. This study could contribute to suggest the irrigation water quality standards and proper agricultural practices including fertilization for indirect wastewater reuse, although long-term monitoring is needed to get more scientific results.

• Membrane and Water Treatment
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• v.10 no.4
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• pp.299-305
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• 2019

Managed aquifer recharge (MAR) systems are gaining interest as an alternative to conventional water resources. However, when the water recovered in MAR systems, dissolved iron and manganese species may easily oxidize and they cause well screen clogging or require abandonment of extraction wells. In this study, both oxic and anoxic conditions were analyzed to verify the feasibility of the membrane filtration performance under various solution chemistries. The fouling mechanisms of the metal ions under anoxic conditions were also investigated by employing synthetic wastewater. The fouled membranes were then further analyzed to verify the major causes of inorganic fouling through SEM and XPS. The newly suggested anoxic process refining existing membrane process is expected to provide more precious information about nanofiltration (NF) membrane fouling, especially for demonstrating the potential advantages to chemical-free drinking water production for indirect potable reuse.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.199-202
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• 2004

Membrane technology is widely employed as a means of producing various qualities of water from surface water, well water, brackish water and seawater. This is also used in industrial wastewater treatment and its recycling process. A large volume of wastewater is generated by the steel industry. Presently, the treated wastewater from the steel industry cannot be recycled, because some of its components cause either direct or indirect problems.(omitted)

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.6
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• pp.53-63
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• 2012

The objectives of this study were to develop a linked watershed-waterbody modeling system and to assess the impacts of indirect wastewater reuse on irrigation water quality. The Osan stream watershed within Gyeonggi-do of South Korea was selected for this study. The linked modeling system was composed of the SWAT (Soil and water assessment tool) and QUALKO2 models. The SWAT model was calibrated and validated using the stream discharge and water quality data from 2010 to 2011. Runoff and non-point source pollutants from each subbasin and stream discharge from 1980 to 2009 were simulated by the SWAT model and applied to the QUALKO2 model. The QUALKO2 model was calibrated and validated under the conditions of low water and normal discharges, respectively. Finally, The 10-day irrigation water quality from April to September was simulated. The statistical measures of coefficient of determination ($R^2$), reliability index (RI), and efficiency index (EI) were used to evaluate the system performance. The $R^2$, RI and EI values ranged from 0.5 to 1.0, 1.03 to 1.92, and -35.03 to 0.95, respectively. The 10-day irrigation water quality showed the concentrations of BOD and coliform exceeded the water quality guidelines for wastewater reuse. The linked modeling system can be a useful tool to estimate non-point source pollutant loads in watershed and to control the water quality of effluent from a wastewater treatment plant and irrigation water in the downstream waterbody.

• Clean Technology
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• v.15 no.2
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• pp.116-121
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• 2009

In this paper, we investigated the effect of an indirect oxidation zone in an electrolysis reactor that used Ti/$IrO_2$ as the anode and SUS 316L as the cathode. Based on our preliminary results, the electrolysis reactor was operated with pole plate interval of 6 mm, current density 1.0 $A/dm^2L$ and electrolyte concentration 15%. The removal efficiency, COD (chemical oxygen demand), was additionally increased by 55% and 12.5${\sim}$15.0% in the direct and indirect oxidation zones, respectively. The removal efficiencies of T-N (total nitrogen) and T-P (total phosphorus) were found to be 88% and 75%, respectively. It was shown that the additional effect of the indirect oxidation zone on the removal was nearly negligible. Also, as the removal of COD,T-N and T-P took place during the initial2${\sim}$5 days of reaction, it was concluded that there was no need to extend the retention time of the electrolysis reactor.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.436-436
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• 2012

하수처리수의 농업용수 재이용에는 직접재이용과 간접재이용이 있으며 대부분의 경우 간접재이용의 형식으로 하수처리수가 농업용수로 이용되고 있다. 전국 130여개의 하수처리장 방류수가 논을 포함한 인근 농경지의 관개용수에 영향을 미치고 있으나 적절한 처리과정 없이 농업용수로 사용되고 있으며, 이는 농민과 농산물 그리고 소비자에게 보건 위생적 영향을 미칠 수 있다. 따라서 하수처리수를 안전하게 농업용수로 간접재이용할 수 있는 연구가 수반되어야 한다. 본 연구에서는 하수처리수의 농업용수 간접재이용에 따른 작물생육, 수질, 토양 환경영향 및 인체위해성 평가 등을 포함한 기초연구를 3년간 진행할 계획이다. 또한 본 연구를 통해서 간접재 이용지구의 유형을 구분하고 이에 따른 저비용, 고효율의 수처리 공정을 개발하며, 간접재이용을 위한 적정 수질기준을 정립하고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.759-759
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• 2012

하수처리수의 농업용수 재이용 사업은 물 재이용 기본계획의 일환으로 수행되고 있다. 재이용방식은 직접재이용과 간접재이용으로 구분할 수 있으며 2020년까지 56개 하수처리시설에서 총 106,388 천$m^3$/년의 농업용수를 직접재이용할 계획이다. 하지만 대부분의 경우 간접재이용의 형식으로 하수처리수를 농업용수로 이용하고 있는 실정이다. 따라서 본 연구의 목적은 하수처리수의 농업용수 간접재이용에 따른 작물생육, 수질, 그리고 토양환경에 미치는 영향을 평가하는데 있다. 본 연구를 위해 수원시 환경사업소와 오산시 환경사업소 하류 지역을 간접재이용 사례지구로 선정하고, 용인 이동저수지를 관개용수로 하는 청정지역을 대비구로 선정하였다. 각 지구별로 수량 구성요소 및 수확량 특성, 그리고 벼의 영양염류 및 중금속 함량 등의 유해성분을 분석하였으며, 관개수질과 논토양의 성분을 모니터링 하였다. 모니터링 결과를 통해 간접재이용 사례지구의 환경영향을 평가하여 수질기준을 정립하고 간접재이용시스템을 개발하는데 있어 기초적인 자료를 제공할 것이라 사료된다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.4 no.4
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• pp.113-125
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• 1984

Water supply has been mainly dependent on the construction of the dams in Korea. It is difficult, however, to continue to construct dams for many reasons, such as the decrease of construction sites, the increase of construction costs, the compensation of residents in flooded areas, and the environmental effects. Water demands have increased and are expected to continue increasing due to the concentration of people in the cities, the rise of the living standard, and rapid industrial growth. It is acutely important to find countermeasures such as development of ground water, desalination, and recycling of waste water to cope with increasing water demands. Recycling waste water includes all means of supplying non-potable water for their respective usages with proper water quality which is not the same quality as potable water. The usages of the recycled water include toilet flushing, air conditioning, car washing, yard watering, road cleaning, park sprinkling, and fire fighting, etc. Raw water for recycling is obtained from drainage water from buildings, toilets, and cooling towers, treated waste water, polluted rivers, ground water, reinfall, etc. The water quantity must be considered as well as its quality in selecting raw water for the recycling. The types of recycling may be classified roughly into closed recycle systems and open recycle systems, which can be further subdivided into individual recycle systems, regional recycle systems and large scale recycle system. The treatment methods of wastewater combine biochemical and physiochemical methods. The former includes activated sludge treatment, bio-disc treatment, and contact aeration treatment, and the latter contains sedimentation, sand filtration, activated carbon adsorption, ozone treatment, chlorination, and membrane filter. The recycling patterns in other countries were investigated and the effects of the recycling were divided into direct and indirect effects. The problems of water reuse in recycle patterns were also studied. The problems include technological, sanitary, and operational problems as well as cost and legislative ones. The duties of installation and administrative organization, structural standards for reuse of water, maintenance and financial disposal were also studied.