• Journal of Environmental Health Sciences
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• v.10 no.1
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• pp.13-20
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• 1984

The hospital wastewaters have to be so disposed as to prevent disease and to protect water resources from hazardous substances disinfectants, medicines, and chemicals. Polyvinylpyrrolidone-iodine complex (povidone-iodine) is widely used in the hospital as one of disinfectants. This study was carried out to manifest the effect of disinfectants in growth of activated sludge in treatment of the hospital wastewater by the activated sludge process. The results are as follow. 1. An average water quality of the hospital wastewater showed 7.2 in pH, 3.2 ppm in DO, 293.3 ppm in SS, 96.0 ppm in BOD, 151.1 ppm in COD, 0.4 ppm in povidone-iodine, 0.5 ppm in phenols, 5.4 ppm in surfactants, 1.6 ppm in o-phosphate, 4.6 ppm in $NH_3-N, 249\times 10^4$ counts/100 ml in coliform group organisms, and $1,369\times 10^2$ counts/ml in general counts of bacteria. And wastewater amounts discharged per bed was calculated 70 l/d/bed. 2. In batch culture activated sludge process, each of cresol and povidone-iodine was not effected in less than 0.1 ppm concentration, but the more concentration, the more inhibit the growth rate of activated sludge. In the mixture of two disinfectants, the growth was more inhibited the effect of single disinfectants. So that this reaction is considered as addition effect of two disinfectants. 3. The removal rates of the disinfectants-by continuous culture activated sludge process were 77.6% in 0.4 ppm povidone-iodine, and in BOD was 85.6%. 4. It is desirable that the hospital wastewater is planed in order to be discharged to two system separately, sewer from life system and wastewater from medical system. From those results, it has been concluded that the hospital wastewater has to be treated safely by the activated sludge process.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.14 no.5
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• pp.1167-1175
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• 1994

The effects of the calculation method of surface runoff on the estimation of flood in urban drainage basin were analyzed in this study. In comparing with surface runoff methods. RUNOFF, ILLUDAS, SBUH and RRL were investigated. To route the flow in sewer/conduits EXTRAN was applied. The Kings Creek and Gray Haven drainage basin's measured data of rainfall and runoff were used in comparing the computed results. The results show that the greatest effect factor on surface runoff in urban small area is the concentration time. The results estimated by each model which are composed with EXTRAN show that the scheme for surface runoff gives considerable effect on the flood hydrograph in urban drainage system. RUN-EX method gives the most similar simulation results among the surface runoff models, and is more applicable for paved and unpaved basins than others.

• Journal of Korean Society on Water Environment
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• v.25 no.3
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• pp.404-410
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• 2009

In this study, research for physical and chemical characteristics were conducted through analysis of sediments, grading and heavy metals (e.g., Mn, Cu, Cd, Zn and Pb ) in sewers which are classified by drainage types. After that, cement solidification and yellow soil calcinations made heavy metals stabilized and then, ways of recycling it were examined. The grain size distribution of all sediments was relative graded. When evaluating heavy metal pollution through index of geoaccumulation (Igeo), Cu showed moderately pollution or strong pollution in forest and street site and Zn was assessed by moderately pollution in military, residential, and street site. Analysis of Pearson Correlation coefficient of heavy metal indicated that all items in street site have tight relationship respectively. Especially, Cd-Zn, Cu-Pb, Cu-Mn, and Pb-Mn have relationship at 99% confidence intervals in statistical analysis. Recycling it with cement solidification was satisfied with compressive strength standard under 55% deposit contents and Zn, Pb, Mn were stabilized effectively. If time and temperature plasticity and compressive strength would be standard, it is revealed that yellow soil calcinations is valuable aggregate when it has 50-60 Wt% contents. When considering economic feasibility and stabilization of heavy metals, cement solidification would be more appropriate than yellow soil calcinations as solution to recycling.

• Journal of Korean Society of Water and Wastewater
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• v.24 no.4
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• pp.443-451
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• 2010

This study was conducted to confirm the CSOs characteristics, and to estimate treatment efficiency of CSO treatment process. Flowrate was average $53,500m^3$/d, maximum $58,100m^3$/d during dry season, but after rain-fall, the flowrate was increased more than twice that of the dry season. And, water pollution concentrations, such as $COD_{Cr}$, SS, $BOD_5$, TN and TP of after rain-fall, were also increased. Thus, for more efficient treatment of pollutants during rainy season, The vortex separator and continuous fiber filter devices were used. From the results on particle range, removal efficiency of particle was 99.7% at the particle size range of $40{\sim}100{\mu}m$ but decreased as 55-80% at the below $40{\mu}m$. The removal efficiencies of $COD_{Cr}$, SS, TN and TP were approx. 70, 60, 70 and 50, respectively during the dry season and approx. 50, 50, 8 and 18% during the rainy season. Also, when compared with the primary sediment basin, $COD_{Cr}$, SS, TN and TP removal efficiencies were high. especially, at the case of TN and TP, TN was more removed than TP because of higher conversion factor value. But we needed more study for the injection of a coagulants to get more stable treatment efficiency for soluble pollutants. Consequently, This process can be used for CSOs treatment as well as replace the primary sedimentation basin during the dry season.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.885-892
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• 2011

In this study, LCA(Life Cycle Assessment) on 'Saemangum CSO Project' was carried out to evaluate environmental impact which occurred during the construction and operation periods and the potential environmental impact reduction was analyzed by comparing production and reduction level of pollution loads. LCA was conducted out according to the procedure of ISO14040 which suggested Goal and Scope Definition, Life Cycle Inventory Analysis, Life Cycle Impact Assessment and Interpretation. In the Goal and Scope Definition, the functional unit was 1 m3 of CSO, the system boundary was construction and operation phases, and the operation period was 20 years. For the data collection and inventory analysis, input energies and materials from civil, architecture, mechanical and electric fields are collected from design sheet but the landscape architecture field is excepted. LCIA(Life Cycle Impact Assessment) was performed following the procedure of Eco-Labelling Type III under 6 categories which were resource depletion, eutrophication, global warming, ozone-layer destruction, and photochemical oxide formation. In the result of LCA, 83.4% of environmental impact occurred in the construction phase and 16.6% in the operation phase. Especially 78% of environmental impact occurred in civil works. The Global warming category showed the highest contribution level in the environmental impact categories. For the analysis on potential environmental impact reduction, the reduction and increased of environmental impact which occurred on construction and operation phases were compared. In the case of considering only the operation phase, the result of the comparison showed that 78% of environmental impact is reduced. On the other hand, when considering both the construction and operation phases, 50% of environmental impact is increase. Therefore, this study showed that eco-friendly material and construction method should be used for reduction of environmental impact during life cycle, and it is strongly necessary to develop technology and skills to reduce environmental impact such as renewable energies.

• Journal of the Korea Computer Industry Society
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• v.3 no.7
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• pp.861-870
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• 2002

The area of business applications in the internet are extended enormously in result of fast development of computing and communication technologies, increase of internet use, and use of intranet/extranet in enterprise information system. Widely spread the use of the internet, there are various applications for Business to Business (B to B) or Business to Customer(B to C) model that are based on the intranet or extranet. This paper designed and implemented the Web-based Electronic Bidding System for Business to Business (B to B) model. The technical issues of electronic bidding system in the internet are involved in the connection between web client and server, electronic data interchange for the contract document, and security solution during the bidding and contracting processes. The web-based electronic bidding system in this paper is implemented using Java applet and servlet as a connection interface for web client and sewer, XML/EDI-based documents for a bid and a contract, and bidding server and notary server for enhancing the security using PKI(Public Key Infrastructure)-based public key cryptography, digital signature and Certification Authority (CA).

• Journal of the Korean Society for Advanced Composite Structures
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• v.3 no.3
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• pp.1-8
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• 2012

Recently, underground pipes are utilized in various fields of applications such as sewer lines, drain lines, water mains, gas lines, telephone and electrical conduits, culverts, oil lines, etc. Most of pipes are installed for long-term purposes and they should be safely installed in consideration of installation conditions because there are unexpected various terrestrial loading conditions. In this paper, we present the result of investigation pertaining to the structural behavior of glass fiber reinforced thermosetting polymer plastic (GFRP) flexible pipes buried underground. The mechanical properties of the GFRP flexible pipes produced in the domestic manufacturer are determined and the results are reported in this paper. In addition, ring deflection is measured by the field tests and the finite element analysis (FEA) is also conducted to simulate the structural behavior of GFRP pipes buried underground. From the field test results, we predicted long-term, up to 50 years, ring deflection of GFRP pipes buried underground based on the method suggested by the existing literature. It was found that the GFRP flexible pipe to be used for cooling water intake system in the nuclear power plant is appropriate because 5% ring deflection limitation for 50 years could be satisfied.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.248-248
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• 2011

본 연구에서는 도시유역 우수관거 시스템의 근본적인 목적인 내수침수 방재 효과를 최대화하기 위하여 첨두 유출량 최소화를 목적으로 하여 개발된 우수관망 최적설계 모형(이정호, 2010)을 이용하여 실제 도시유역에 대하여 다양한 인공적인 강우 사상들을 적용하여 실제 강우 발생 시 첨두유출량 저감의 효과가 발생할 수 있을 것인가에 대하여 분석하였다. 본 연구에서 이용한 최적 우수관망 노선 결정 모형은 이정호(2010)가 개발한 모형으로 도시유역에서의 우수관망의 노선 결정을 유출구에서의 첨두유출량을 최소화하는 것을 목적으로 이루어지도록 최적화기법을 이용하여 개발한 모형이다. 이정호(2010)는 개발된 모형을 통하여 도시유역에서 유출구 첨두유출량을 최소화하여 관망 노선을 결정한 결과 설계빈도를 초과하는 강우에 대해서 내수침수 발생이 저감되는 효과를 가져올 수 있음을 분석하였다. 본 연구에서는 이러한 이정호(2010)의 우수관망 최적 설계 모형의 적용성을 검증하기 위하여 각기 다른 인공적인 강우를 적용하여 최적화된 우수관망에서의 유출구 첨두유출량의 저감 양상을 분석하였다. 분석에 적용된 강우사상은 설계빈도에 해당하는 강우사상에 대하여 강우의 첨두치가 일정한 시간 간격을 두고 연속되어 발생하는 강우사상들에 대하여 모의하였다. 분석 결과 강우의 첨두치가 연속되는 경우에도 최적화된 관망에서의 첨두 유출량은 현재의 관망에 비하여 감소치가 두드러지게 나타남을 알 수 있었다. 또한 강우의 첨두유출량 발생 시각은 각 우수관망별로 1분 및 2분 정도의 차이를 나타내고 있으며, 따라서 최적화된 우수관망이 시스템 내의 지체 현상에 따른 첨두유출량 감소를 유발하는 것이 아닌 관망 전체에서의 유입량의 적정 분배에 따른 것임을 나타낸다.

• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.247-247
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• 2011

도시유역에서의 일반적인 우수관거 설계 및 기존의 연구들은 수리학적 조건을 만족시키는 범위 내에서 최소의 비용을 위한 관거 설계에 초점을 맞추어왔다. 그러나 최적의 우수관거 설계는 우수관거의 근본적 목적인 내수배제를 최대화 하고자 하는 것이며, 이것은 관망 구성에 따른 시스템 내 유입 수문곡선들 간의 중첩효과를 제어함으로써 가능하다. 본 연구에서는 관내 흐름의 변화를 관망의구성에 따라서 제어될 수 있는 목적함수로서 다루고 있는 이정호(2010)의 우수관망 최적설계 모형에 대하여 각기 다른 유역 특성을 나타내는 실제 도시유역에서의 적용성을 검토하였다. 본 연구에서 이용한 최적 우수관망 노선 결정 모형은 이정호(2010)가 개발한 모형으로 도시유역에서의 우수관망의 노선 결정을 유출구 첨두유출량 최소화를 목적으로 최적화기법을 이용한 모형이다. 이정호(2010)는 개발된 모형을 통하여 관망 노선을 결정한 결과 설계빈도를 초과하는 강우에 대해서 내수침수 발생이 저감되는 효과를 가져올 수 있음을 분석하였다. 본 연구에서는 이러한 이정호(2010)의 모형에 대한 적용성을 검증하기 위하여 각기 다른 유역 특성을 갖는 실제 도시유역들에 대하여 해당 모형을 적용하였다. 이때 유역의 특성은 지표유출 및 첨두유출량에 지배적인 영향을 미치는 유역의 지표 경사에 대하여 고려되었다. 적용된 도시유역은 총 3개 배수분구로서 평균 지표 경사는 0.008, 0.006, 0.002로 각기 높은 경사, 보통 경사 및 완만한 경사 지대를 염두에 둔 유역 선정에 해당한다. 이에 따라 각 유역에 대하여 우수관망 노선을 최적화한 결과 설계빈도의 강우지속기간 30분 강우에 대하여 현재의 관망 대비 최적화된 관망에서의 첨두유출량 저감 비율은 지표경사 0.008인 유역에서는 약 7%, 지표경사 0.006인 유역에서는 약 17%, 지표경사 약 0.002인 유역에서는 약 8%로 나타났다. 따라서 본 연구결과 유역의 경사 특성에 따른 최적 우수관망을 통한 첨두유출량의 저감 비율간에는 상관관계를 정의할 수 없으며, 단지 우수관망에서의 노선 변경이 가능한 맨홀 지점이 어떤 중요한 지점에 얼마나 위치하느냐에 따라 달라지게 되는 것으로 분석되었다.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.06a
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• pp.95-112
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• 1998

Water quality in the public water course has been polluted more seriously than ever before due to the increase of the number and aremount of pollution sources such as domestic and industrial wastewater. For water quality conservation, the Korean government has been trying to construct sewage treatment facilities continually, of which treatment capacity reached to 11,452,400m$^{3}$/day in 1996. Night soil treatment facilites of m nationwide have the treatment capacity of 24,038m$^{3}$/day. But water quality has not been improved because the sewer systems were insufficient and the treatment efficiencies of sewage were not high, enough. For renovation of water quality, miscellaneous domestic wastewater must be treated because 27g BOD/day out of total 40g BOD/person-day come from miscellaneous wastewater, comparing to 13g BOD/day from night soil. However, sole treatment purifier treat only night soil from the flushing toilet. Therefore, it may be desirable to treat the miscellaneous domestic wastewater and the night soil from flushing toilet together by joint treatment purifier system as on-site domestic wastewater treatment technology. In Korea, the joint treatment purifier system, introduced in 1997, have the benefit as follows; i) good water poiluion control effect, ii ) good effect on river water flow, iii) water pollution control with sewage treatment facility, and iv) rapid pollution control effect, etc. In order to achieve a good effect as stated before, i ) strengthening effluent guideline including BOD, nitrogen and phosphorus, ii ) specializing operation to maintain high performance, and iii) supporting its construction and maintenance costs by the governmental level may be necessary: In addition, automation system of joint treatment purifier, technology for its package and compactness, and a new bio-media bio-filter with higher capacity should be further developed in agreement with a more stringent effluent guideline.