• 상하수도학회지
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• 제11권3호
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• pp.87-95
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• 1997

A river water quality management model was made by Dynamic programming. This model optimizes the wastewater treatment cost of the application area, and computed water quality with it must meet the water quality standard. And this model takes into consideration tributary input, wastewater treatment plant effluent, withdrawls for several purposes. Modified Streeter-Phelps equation was used to calculate BOD and DO. Optimization problem was solved with particular exceedance probability flow, and the water quality of each point was calculated with the decided treatment efficiencies. At that time, the probability satisfying the water quality standard of constraints to the exceedance probability of the flow. The developed model was applied to the lower part of the Han-River. The reliability to meet the water quality standard is 70 % when 4 wastewater treatment plants of Seoul City are operated by activated sludge system at autumn of the year 2001. Treatment cost of this case is 121.288 billion won per year.

• 한국농공학회지
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• 제44권4호
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• pp.139-148
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• 2002

Pilot study was performed to examine the feasibility of the pond system for further polishing of treatment wetland effluent from December 2000 to June 2001. The wetland system used for the experiment was highly effective to treat the sewage during the growing season, but it was less effective and its effluent was still high to discharge to the receiving water body. Therefore, the wetland effluent may need further treatment to prevent water quality degradation. Pond system could be used to hold and further polish the wetland effluent during the winter season and ots feasibility was evaluated in this study. Additional water quality improvement was apparent in the pond system during winter season, and the pond effluent could be good enough to meet the effluent water quality standards if it is properly managed. Timing of the pond effluent discharge appears to be critical for pond system management because it is a closed system and whole water quality constituents are affected by physical, chemical, and biological pond environments. Once algae started to grow in mid-April, constituents in the pond water column interact each other actively and its control becomes more complicated. Therefore, upper layer of the pond water column which is clearer than the lower layer my need be discharged in March right after ice cover melted. In the experiment, water quality of the upper water column was markedly clear in March than ant other times probably because of freezing-thawing effect. The remaining lower water column could be further treated by natural purification as temperature goes up or diluted with better quality of wetland effluent for appropriate water uses. This study demonstrated the feasibility of pond system for subsequent management of wetland effluent during the winter season, however, more study is needed for field application.

• Journal of Advanced Marine Engineering and Technology
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• 제34권3호
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• pp.391-398
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• 2010

This study is currently giving priority to developing the ballast water treatment system using ozone(Ozone BWTS). The Ozone BWTS, were equipped on the real merchant vessel named as M. V. Hyundai Hong Kong to carried out shipboard tests of ballast water treatment system in accordance with orders of IMO G8 Guidelines. The study results show that the Ozone BWTS is capable of meeting the Ballast Water Performance Standard under Regulation D-.2 of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, and also the more stringent standards being proposed under US legislation.

• 대한환경공학회지
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• 제37권2호
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• pp.126-135
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• 2015

도시지역의 소하천은 불투수 면적의 증가 및 우수관거의 발달로 인해 유역의 오염물질 및 강우 유출수의 유달률이 증가한 반면 비강우시에 현저하게 유량이 감소되어 하천환경에 심각한 문제를 나타내고 있다. 본 연구에서는 도시 하천의 유량과 수질 문제를 저감하기 위해 개발된 초기강우 저류 및 처리시설을 효율적으로 운영하기 위해 SWMM 도시유역모델 적용 결과와 자동모니터링 시스템을 이용하는 종합관리시스템을 개발하였다. 본 연구의 대상 지역인 관평천 유역의 대부분의 강우사상에서 오염물질은 초기 4시간의 강우 유출수에 집중되어 있는 것으로 관찰되었으며 이는 처리시설의 용량 결정에 있어 가장 중요한 인자로 작용한다. 본 시험 유역에서 유역모델인 SWMM을 이용하여 계산한 결과 처리시설에서 수용할 수 있는 초기우수 유출량은 약 6 mm의 누적강우량으로 산정되었으며 이는 대상지역에서 발생하는 대부분의 소규모 강우에 대해 처리가 가능하다는 것을 의미한다. 본 연구 결과는 강우-유출 모델과 연계한 초기우수 처리시설 운영을 위한 가이드라인을 제시하고 있으며, 하천 수질 모델과 연결할 경우 유입하천에 미치는 영향을 사전에 예측할 수 있으며, 유역의 조건과 연계하여 도시하천의 유역연계 종합 수질관리를 위한 중요한 자료를 제공할 수 있을 것이다.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2016년도 추계학술대회 논문집
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• pp.172-172
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• 2016

The International Maritime Organization(IMO) adopted the International Convention for the Control and Management of Ships' Ballast Water and Sediments in 2004 to prevent the transfer of aquatic organisms via ballast water. Forty ballast water treatment systems were granted final approval. A variety of techniques have been developed for ballast water treatment including UV treatment, indirect or direct electrolysis, ozone treatment, chemical compounds and plasma-arc method. In particular, using plasma and ozone nano-bubble treatments have been attracted in the fields. However, these treatment systems have a problem such as remained toxic substance, demand for high power source, low efficiency, ets. In this paper, we present our strilization results obtained from membrane type electrolytic-reduction treatment system The core of an electrolysis unit is an electrochemical cell, which is filled with pure water and has two electrodes connected with an external power supply. At a certain voltage, which is called critical voltage, between both electrodes, the electrodes start to produce hydrogen gas at the negatively biased electrode and oxygen gas at the positively biased electrode. The amount of gases produced per unit time is directly related to the current that passes through the electrochemical cell. From the results, we could confirm the sterilization effect of bacteria such as S. aureus, E. Coli and demonstrate the mechanism of sterilization phenomena by electrolytic-reduction treatment system.

• 한국물환경학회지
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• 제29권5호
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• pp.656-665
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• 2013

This research was conducted to investigate pollutant load unit factor from aquacultural farms. Pollutant load unit factors were investigated on the 13 kinds of fish type, i.e., Trout, Leather Carp, Eel, Carp, Cartfish, Freshwater Eel, Crucian Carp, Colored Carp, Sturgeon, Marsh Snail, Sweetfish, Pond Snail, Eriocheir Sinensis. Water qualities in aquacultural farms were investigated wide range of values by fish type and pollutant items. High BOD and COD values were observed at the Leather Carp (Ponded water system), Cartfish (Ponded water system) and Freshwater Eel (Recirculating System). TOC and DOC values were relatively high at the Freshwater Eel (Recirculating System) and Eriocheir Sinensis (Extensive). Eel (Ponded water system) and Freshwater Eel (Recirculating System) produced high concentrated nutrient pollutants, i.e., T-N, T-P. Pollutant load unit factors are dependent on fish type, aquacultural type, water quality items, etc. If some fishes have similar basic unit values, those could be applied for TMDLs as a group of fish having same pollutant load unit. The water quality concentrations of post treatment facilities' (mainly reservoir tank) effluent were higher than those of fish raising bath because of extracting pollutant from sediment in the reservoir tank. Therefore, it needs to the management and regulations about post treatment facilities.

• 한국물환경학회지
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• 제24권6호
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• pp.676-681
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• 2008

The evaluation of the effluent water quality of sewage treatment plant is one of the most important factor in calculating total maximum daily loads (TMDLs). Current method to calculate 95% upper limit of effluent water quality of sewage treatment plant assuming normal distribution of data needs to be implemented in case of non-normal distribution. We have investigated the applicability of percentile ranking method as a non-parametric statistical analysis in case of non-normal distribution of data.

• 상하수도학회지
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• 제34권1호
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• pp.9-21
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• 2020

The proper operation and safety management of water and wastewater treatment systems are essential for providing stable water service to the public. However, various natural disasters including floods, large storms, volcano eruptions and earthquakes threaten public water services by causing serious damage to water and wastewater treatment plants and pipeline systems. Korea is known as a country that is relatively safe from earthquakes, but the recent increase in the frequency of earthquakes has increased the need for a proper earthquake management system. Interest in research and the establishment of legal regulations has increased, especially since the large earthquake in Gyeongju in 2016. Currently, earthquakes in Korea are managed by legal regulations and guidelines integrated with other disasters such as floods and large storms. The legal system has long been controlled and relatively well managed, but technical research has made limited progress since it was considered in the past that Korea is safe from earthquake damage. Various technologies, including seismic design and earthquake forecasting, are required to minimize possible damages from earthquakes, so proper research is essential. This paper reviews the current state of technology development and legal management systems to prevent damages and restore water and wastewater treatment systems after earthquakes in Korea and other countries. High technologies such as unmanned aerial vehicles, wireless networks and real-time monitoring systems are already being applied to water and wastewater treatment processes, and to further establish the optimal system for earthquake response in water and wastewater treatment facilities, continuous research in connection with the Fourth Industrial Revolution, including information and communications technologies, is essential.

• Journal of Advanced Marine Engineering and Technology
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• 제34권3호
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• pp.383-390
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• 2010

This study is currently giving priority to developing the ship's ballast water treatment system using ozone (Ozone BWTS). The Ozone BWTS was tested in a full scale land-based mobile barge to evaluate performance according to the IMO G8 Guidelines. Test cycles using the mobile-barge were conducted in seawater and brackish water in the vicinity of the Port of Busan and Nakdong River, Republic of Korea. All tests were conducted according to the requirements of the G8 Guidelines. Test results show that the Ozone BWTS meets the Ballast Water Performance Standard contained in Regulation D-2 of the IMO Ballast Water Management Convention, as well as all of the operational, safety, and environmental testing requirements of the G8 Guidelines, as required for type approval of IMO. The study results show that the Ozone BWTS is capable of meeting the Ballast Water Performance Standard under Regulation D-2 of the International Convention for the Control and Management of Ships’ Ballast Water and Sediments, and also the more stringent standards being proposed under US legislation.

• Journal of Advanced Marine Engineering and Technology
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• 제33권2호
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• pp.282-287
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• 2009

As current international guideline and IMO regulation give severe restrictions for ships to manage ballast water to reduce unintentional organism transfers, several ballast water treatment systems recently have been being developed together with filtration. That is because discharging ballast water from ships causes many pollutions by foreign biological invasive species. The primary treatment system being considered in this study was based on fine screen filtration technology applied to ballast water filter in ballast tank in order to reduce the load of ballast water treatment system. New ballast water filtration system was invented and analysed. The structural stress and strain analysis for ballast filtration systems which are current and invented filters were carried out using UGS and Ansys. The results showed that the structure of current filtering module was not designed to meet the requirement of sea water filtration during ballasting operation. The studies also showed that the invented design of filtration system equipped with back washing and automatic scrapper for eliminating cake of bio-species might be a potentially effective technology for ballast water management of ship's ballast tank.