• Journal of environmental and Sanitary engineering
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• v.8 no.2
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• pp.65-84
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• 1993

This study reviewed the current status and problems of sewerage system in Korea and then proposed possible methods to correct the problems. Also, evaluation of future development in sewerage system is included. It can be summarized as follows : 1. Investment in sewerage system is relatively low . 0.23% of GNP, Considering that the investment portion is 0.35% in OECD and 0.63% in Japan, it should be increased further. 2. The reasons wily the investment in sewerage system is low can be ' (1) Low priority is given to the investment in sewerage system. Local government builds and operates its own wastewater treatment plant. Local government as well as residents prefer to invest their money in roadwork, housing and parks to in wastewater treatment facilities because of greater investment effects. (2) Besides capital investment, more maintenance cost is needed for sewerage system. Proper operation of wastewater treatment facilities requires a well-trained operator. Because of public conception that operation of wastewater treatment facility is a dirty job, it is difficult to find a well-trained operator. (3) It is difficult to estimate the effect of sewerage system (4) Cost required to build and maintain wastewater treatment facility should be paid by people, who benefit from the facility. People to benefit are sometimes different from people to pay. 3. Advanced treatment is necessary to protect the bay aura and raw water source as well as to prevent eutrophication of lakes and ponds. 4. Wastewater treatment facility were mainly build in big cities during the decade of 1980. Followings should be solved first to expand the facilities. (1) Rapid repair and construction of sewer. (2) Technical development of wastewater treatment . Prevention of efficient and economical wastewater . Development of efficient and economical wastewater treatment techniques . Development of high-efficiency treatment using bioreactor . Reuse of wastewater treatment plant effluent (3) Sludge treatment and disposal . Composting of sludge cakes . Development of techniques to reduce the volume of sludge cake : incineration and reuse of sludge ash and slag. (4) Utilization of wastewater treatment facilities . Construction of community parks or sports families(ie, on the tops of the covered aeration tanks and sedimention tanks) Construction of wastewater treatment facilities under ground and of parking facilities and community parks above ground. (5) Education of wastewater treatment personal.

• Journal of Korean Society of Water and Wastewater
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• v.28 no.3
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• pp.315-324
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• 2014

The residents' odor complaint is steadily increasing by odor causing from sewage system. A current drainage facilities and septic tank are included in the individual sewerage according to Sewerage Act. However, definitions and legal standards of drainage tank are insufficient. In addition, specifications and maintenance standards related to structure and size are not established. In this research, effect of drainage tank in individual sewage facilities on the odor occurrence was studied and the concentrations of $H_2S$ and composite odor were measured. From the measurements, the concentration of $H_2S$ and composite odor were 1 ppm ~ 5 ppm and 1.04 OU ~ 4.05 OU, respectively, before pump operation. Also, the concentration of $H_2S$ and composite odor were 5 ppm ~ 33 ppm and 5.10 OU ~ 35.04 OU, respectively, after pump operation. The concentration of SS in the effluent from drainage tank was ranged from 840 mg/L to 1,980 mg/L. These high concentration of SS seemed to be the major source of foul smell when high concentrated suspended solids in the public sewerage system were decomposed and then emitted. In this research, correlation coefficient ($R^2$) between $H_2S$ and composite odor before and after pumping were 0.925 and 0.918, respectively.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.2D
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• pp.255-266
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• 2011

In order to evaluate the environmental load occurring from the whole life cycle of a facility, LCA (Life Cycle Assessment) adopted by ISO is not only applied as an individual product but rather a complicated system involving buildings and/or infrastructure in a wide range of scope. The introducing of LCA to a wastewater reuse facility will assist to understand not only the treatment of water contaminants but also the overall system related to the interaction of involved, potential issues. This research implemented LCA for the establishment of the wastewater reuse facility. The results show that a fresh water aquatic Eco-toxicological Impact (88.3%) is the largest environment concern and the maintenance & operation phase has the most impact on the environment utilizing life cycle for the wastewater reuse facility. The civil works and chemical treatments in the maintenance & operation phase led to the biggest environmental impact. The results of this research can provide pertinent data of investigating opportunities for environmental improvement not limited to public officers regulating environmental policies, and could be used to make decisions for an environmentally sound and sustainable design in the initial phase of construction.

• Nuclear Engineering and Technology
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• v.45 no.5
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• pp.625-636
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• 2013

Pressing demands of economic competitiveness, the need for large-scale deployment, minimizing the need of human intervention, and experience from the past events and incidents at operating reactors have guided the evolution and innovations in reactor technologies. Indian innovative reactor 'AHWR' is a pressure-tube type natural circulation based boiling water reactor that is designed to meet such requirements, which essentially reflect the needs of next generation reactors. The reactor employs various passive features to prevent and mitigate accidental conditions, like a slightly negative void reactivity coefficient, passive poison injection to scram the reactor in event of failure of the wired shutdown systems, a large elevated pool of water as a heat sink inside the containment, passive decay heat removal based on natural circulation and passive valves, passive ECC injection, etc. It is designed to meet the fundamental safety requirements of safe shutdown, safe decay heat removal and confinement of activity with no impact in public domain, and hence, no need for emergency planning under all conceivable scenarios. This paper examines the role of the various passive safety systems in prevention and mitigation of severe plant conditions that may arise in event of multiple failures. For the purpose of demonstration of the effectiveness of its passive features, postulated scenarios on the lines of three major severe accidents in the history of nuclear power reactors are considered, namely; the Three Mile Island (TMI), Chernobyl and Fukushima accidents. Severe plant conditions along the lines of these scenarios are postulated to the extent conceivable in the reactor under consideration and analyzed using best estimate system thermal-hydraulics code RELAP5/Mod3.2. It is found that the various passive systems incorporated enable the reactor to tolerate the postulated accident conditions without causing severe plant conditions and core degradation.

• Safety and Health at Work
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• v.1 no.2
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• pp.175-182
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• 2010

Objectives: This study examined how ethanolamines (EAs) with the same functional alcohol group ($HOCH_2CH_2$), such as mono-EA (MEA), di-EA (DEA), and tri-EA (TEA), in water-based metalworking fluids (wbMWFs) are vaporized, condensed, and transformed by heat generated during metalworking. Methods: Two types of experimental apparatus were manufactured to achieve these objectives. Results: Vaporization tests using a water bath showed that the vaporization rate increased markedly from $0.19\;mg/m^2{\cdot}min$ at $23.5^{\circ}C$ to $8.04\;mg/m^2{\cdot}min$ at $60^{\circ}C$. Chamber tests with a heat bulb revealed that "spiked" MEA was fully recovered, while only 13.32% of DEA and no TEA were recovered. Interestingly, non-spiked types of EAs were detected, indicating that heat could convert EAs with more alcohol groups (TEA or DEA) into other EAs with fewer group(s) (DEA or MEA). The EA composition in fresh fluid was 4% DEA, 66% TEA, and 30% MEA, and in used fluids (n = 5) was 12.4% DEA, 68% TEA, and 23% MEA. Conversion from TEA into DEA may therefore contribute to the DEA increment. Airborne TEA was not detected in 13 samples taken from the central coolant system and near a conveyor belt where no machining work was performed. The DEA concentration was $0.45\;mg/m^3$ in the only two samples from those locations. In contrast, airborne MEA was found in all samples (n = 53) regardless of the operation type. Conclusion: MEAs easily evaporated even when MWFs were applied, cleaned, refilled, and when they were in fluid storage tanks without any metalworking being performed. The conversion of TEA to DEA and MEA was found in the machining operations.

• Journal of Korean Society of Water and Wastewater
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• v.35 no.1
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• pp.53-61
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• 2021

The quantified analysis of damages to wastewater treatment plants by natural disasters is essential to maintain the stability of wastewater treatment systems. However, studies on the quantified analysis of natural disaster effects on wastewater treatment systems are very rare. In this study, a total disaster index (DI) was developed to quantify the various damages to wastewater treatment systems from natural disasters using two statistical methods (i.e., AHP: analytic hierarchy process and PCA: principal component analysis). Typhoons, heavy rain, and earthquakes are considered as three major natural disasters for the development of the DI. A total of 15 input variables from public open-source data (e.g., statistical yearbook of wastewater treatment system, meteorological data and financial status in local governments) were used for the development of a DI for 199 wastewater treatment plants in Korea. The total DI was calculated from the weighted sum of the disaster indices of the three natural disasters (i.e., TI for typhoon, RI for heavy rain, and EI for earthquake). The three disaster indices of each natural disaster were determined from four components, such as possibility of occurrence and expected damages. The relative weights of the four components to calculate the disaster indices (TI, RI and EI) for each of the three natural disasters were also determined from AHP. PCA was used to determine the relative weights of the input variables to calculate the four components. The relative weights of TI, RI and EI to calculate total DI were determined as 0.547, 0.306, and 0.147 respectively.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.6-6
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• 2020

하천관리정책은 국가의 자연적, 사회적 환경에 크게 영향을 받으며 각 나라에 맞는 고유한 방향으로 정착하였다. 우리나라의 경우 치수와 개발이 중심이 있는 되는 일본식 하천관리체계를 오랫동안 유지하여 왔으며 개별 하천의 관리에 기본이 되는 하천기본계획체계는 일본의 신하천법의 형식을 유지하고 있다. 이에 반해 물관리체계는 2019년 6월에 시행된 물관리기본법에 의해 수량과 수질 통합관리 체계로 크게 개편되었다. 현행 물관리체계에서는 수질과 수량은 관리주체가 통합되었으나 하천관리는 하천시설물과 하천수의 관리주체가 분리되어 있다. 기후변화로 인해 주요 선진국은 하천관리에서 치수의 중요성이 높아지고 있으나 우리나라의 경우에는 하천의 치수관리에 대한 정책적 중요도는 떨어지고 있으며 환경관리에 대한 중요도가 높아지고 있다. 하천기본계획은 개별 하천에 대한 치수, 이수, 환경의 유일한 종합적 계획으로 광범위한 조사/분석/계획 등을 포함하고 있으나 타계획과의 연관성이나 활용성이 높지 않은 편이다. 본 연구에서는 국가 차원의 종합적인 하천관리정책 수립, 일관성 있는 치수, 이수, 환경 계획의 수립, 정부의 효율적인 하천관리 실행 등의 관점에서 현행 하천기본계획의 한계를 살펴보고 변화하는 기후 및 사회 환경에 탄력적으로 대응할 수 있는 개선방안을 검토하였다. 이를 위해서 우리나라와 일본, 미국, 유럽 등 선진국의 하천관리체계를 검토하고 도로, 상하수도 등 유사 분야의 계획 체계와 하천계획 체계를 비교하였다. 물관리 체계 개편을 고려한 현행 하천기본계획의 주요 논점을 정리하고 현행 법체계와 사회환경을 고려하여 하천기본계획이 실질적인 하천에 대한 종합적 계획의 의미를 살릴 수 있는 체계 개편 방안과 구체적인 실행방안에 대해서 고찰하였으며 장단기 개선방안을 제시하고자 한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.6
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• pp.1901-1910
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• 2014

Current domestic and overseas BIM practice and research efforts show very few examples that design and construction BIM data could be successfully used for efficient operation and maintenance (O&M) of infrastructure in particular. This study takes public wastewater treatment plant requiring an enhancement of operation and maintenance capability into account to develop a prototype BIM-based maintenance management system. The system is designed and implemented following a typical system development procedure and validated by the system outputs per four scenarios being considered to be main maintenance activities: The research results are expected to contribute to the upgrade of current wastewater treatment plant maintenance level, which is more demanded as water-related regulation and policy direction changes to region-based large scale O&M and asset management adoption, and overseas market participation.

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.5
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• pp.131-138
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• 2009

In this paper, a dynamic warning system to forecast inland flooding associated with typhoons and storms is described. The system is used operationally during the typhoon season to anticipate the potential impact such as inland flooding on the coastal zone of interest. The system has been developed for the use of the public and emergency management officials. Simple typhoon models for quick prediction of wind fields are implemented in a user-friendly way by using a Graphical User Interface (GUI) of MATLAB. The main program for simulating tides, depth-averaged tidal currents, wind-driven surges and currents was also vectorized for the fast performance by MATLAB. By pushing buttons and clicking the typhoon paths, the user is able to obtain real-time water level fluctuation of specific points and the flooding zone. This system would guide local officials to make systematic use of threat information possible. However, the model results are sensitive to typhoon path, and it is yet difficult to provide accurate information to local emergency managers.

• The Journal of the Korea Contents Association
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• v.19 no.6
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• pp.236-248
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• 2019

Green belts can help to set boundary for city growth, provide ecological protection system and enhance the resilience of Beijing. During the implementation period of the current overall city planning of Beijing, the proportion of green space varies much among the sub-districts, villages and towns involved in the two green belts in the research. With this as starting point, by researching the correlations of 'city system factors' and 'planning policy factors' with the change in the scale of green space, the paper discussed the influential factors of implementing the planning of green space of Beijing, and conducted quantitative research, with such possible influential factors classified into 'city system factors' and 'planning policy factors'. Through multiple linear regression model, the paper tested the correlations of city system factors and planning policy factors (independent variable) with the increment in the construction land in green belts (dependent variable). Through influence to population aggregation and the expansion force of construction land, city system factors such as mountain land and water, house rent of unit area, accessibility of public transport and the newly-defined state-owned construction land generate correlation with the change in the scale of construction land in green belts.