• Proceedings of the Korean Environmental Sciences Society Conference
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• 2004.11a
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• pp.205-206
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• 2004

국내 정수처리에 있어 기존 장티프스, 콜레라 등과 같은 병원성 세균의 소독 뿐만아니라 최근에는 지아디아, 크립토스포리디움과 같은 병원성 원생동물의 불활성화에 대하여 많은 관심을 가져야 하며 적정한 소독능을 확보하기 위해서는 정수지의 도류벽 설치, 용량확장, 수위비조절 및 잔류염소 농도 조절 등의 운영 및 시설개선이 필요한 것으로 판단된다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.11a
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• pp.291-292
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• 2003

잔류성 유기오염물질(POPs; Persistent Organic Pollutants)은 환경 내에서 분해가 느려 잔류성이 높고, 생체 지질에 축적되는 독성이 강한 특성이 있다. 따라서 스톡홀름 협약(2001년 5월 23일)에서 12종의 POPs 물질에 대해 국제적 사용금지 및 관리가 결정되었다. POPs는 대부분 반휘발성(semi-volatile) 이어서 대기 중 장거리 이동되어 배출지와 다른 곳에 침적되는 것이 보고되어있다. 이러한 물질들의 대기 중 잔류량과 기체상과 입자상의 분포 특성을 살펴서 환경 내 이동성을 파악하는 것은 인체위해성 수준을 알아내는데 중요한 자료이다. (중략)

• Journal of Korea Water Resources Association
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• v.54 no.9
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• pp.643-656
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• 2021

Recently, water supply management technology is highly developed, and a computer simulation model plays a critical role for estimating hydraulics and water quality in water distribution networks (WDNs). However, a simulation of complex large water networks is computationally intensive, especially for the water quality simulations, which require a short simulation time step and a long simulation time period. Thus, it is often prohibitive to analyze the water quality in real-scale water networks. In this study, in order to improve the computational efficiency of water quality simulations in complex water networks, a hierarchical water-quality-simulation technique was proposed. The water network is hierarchically divided into two sub-networks for improvement of computing efficiency while preserving water quality simulation accuracy. The proposed approach was applied to a large-scale real-life water network that is currently operating in South Korea, and demonstrated a spatiotemporal distribution of chlorine concentration under diverse chlorine injection scenarios.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.1
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• pp.1-6
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• 2012

Down Stream K River has high COD (4-10 mg/L) and high $NH_3$-N concentration (3.5 mg/L during winter period). Although $NH_3$-N itself is not reported harmful at this level, it must be removed to meet drinking water standard (0.5 mg/L). We constructed a pilot plant modifying the processes of conventional drinking water facilities. Prechlorination and powdered activated carbon (PAC) dechlorination was adopted prior to a flocculation tank to remove ammonia and prevent disinfection byproducts (DBPs) formation. Also, GAC processes was included after sand filter to remove residual DOC. This pilot having a capacity of 36 ton/day was operated for one year. The GAC processes were successful to remove ammonia and many organic pollutants (DOC, MBAS, UV-254 nm absorbance, etc). Influent DOC concentrations were very high as 3~6 mg/L throughout the plant operation. It was impossible to achieve 1.0 mg/L effluent DOC, indicating that bed depth (2 m) should be increased to achieve more strict DOC quality standards. When $Cl_2$ dose was well controlled ($Cl_2/NH_3$-N ratio 10~11 on a weight basis), $NH_3$-N removal was 98% and THMs was very low possibly due to low free residual chlorine and PAC dechlorination.

• Journal of Korean Society of Environmental Engineers
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• v.32 no.10
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• pp.916-927
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• 2010

In general water treatment process, the disinfection process by chlorine is used to prevent water borne disease and microbial regrowth in water distribution system. Because chlorines were reacted with organic matter, carcinogens such as disinfection by-products (DBPs) were produced in drinking water. Therefore, a suitable injection of chlorine is need to decrease DBPs. Rechlorination in water pipelines or reservoirs are recently increased to secure the residual chlorine in the end of water pipelines. EPANET 2.0 developed by the U.S. Environmental Protection Agency (EPA) is used to compute the optimal chlorine injection in water treatment plant and to predict the dosage of rechlorination into water distribution system. The bulk decay constant ($k_{bulk}$) was drawn by bottle test and the wall decay constant ($k_{wall}$) was derived from using systermatic analysis method for water quality modeling in target region. In order to predict water quality based on hydraulic analysis model, residual chlorine concentration was forecasted in water distribution system. The formation of DBPs such as trihalomethanes (THMs) was verified with chlorine dosage in lab-scale test. The bulk decay constant ($k_{bulk}$) was rapidly decreased with increasing temperature in the early time. In the case of 25 degrees celsius, the bulk decay constant ($k_{bulk}$) decreased over half after 25 hours later. In this study, there were able to calculate about optimal rechlorine dosage and select on profitable sites in the network map.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.490-490
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• 2021

상수도 관망은 대표적인 사회기반시설로 수원으로부터 수용가에게 수질적으로 안전한 물을 안정하게 공급하는 것을 목표로 한다. 초기의 상수도 관망의 최적 설계는 비용만을 고려함으로써 미래의 불확실한 상황에 대한 대처가 매우 취약하고, 사용자의 다양한 요구를 충족시키지 못하였다. 또한, 유량과 안정적인 수질 공급을 고려하는 설계는 몇몇 비선형적 요소를 포함하고 있으며, 특히 사용자의 수요 패턴에 따른 잔류 염소 농도가 설계 기준에 부합하지 못하는 문제가 되는 경우 사용자의 심미적, 심리적 불편을 초래할 수 있다. 이는, 수질의 안전성과 직결되는 문제이다. 따라서 본 연구에서는 상수도 관망의 설계에 대하여 수질과 수리학적 특성을 고려한 상수도 관망 다목적 최적 설계를 수행하였다. 상수도 관망은 수질적인 측면을 고려하기 위해 수원에서 수용가까지 용수를 공급하는 과정에서 병원성 미생물을 소독하기 위하여 염소를 주입한다. 또한, 유리 잔류 염소의 평상시 기준을 (1.0-4.0mg/L) 유지하도록 규정하였다 (수도법 시행규칙 제22조의2). 하지만 사용자의 사용패턴, 체류 시간에 따라 잔류염소량이 달라진다. 따라서, 본 연구에서는 상수도 관망의 설계 비용과 염소 주입량을 동시에 설계 인자로서 고려하기 위해 Multi-objective Harmony Search를 적용하고, 그 결과를 분석하였다. 이러한 상수도 관망의 수질 인자와 설계 비용을 고려한 최적 설계안은 경제적 측면 뿐만 아니라 사용자의 수질 측면의 안전성을 충족하는 방안을 제시할 수 있다.

• 한국상하수도협회지
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• s.12
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• pp.138-145
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• 2005

• 수도
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• v.24 no.4 s.85
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• pp.88-96
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• 1997

• Journal of Korean Society of Environmental Engineers
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• v.28 no.1
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• pp.26-33
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• 2006

This study investigated the characteristics of the biofilm removal by free chlorine or monochloramine. The simulated drinking water distribution pipes on which biofilms had been formed were supplied with tap water containing 0.5, 1.0, 2.0 mg/L of free chlorine or monochloramine residuals. The biofilm removal was characterized by measurement of attached HPC and biomass on pipe surfaces. Chlorine was more effective in both inactivation of attached viable heterotrophic bacteria and removal of biofilm biomass compared to monochloramine. Biofilm matrix was not much eliminated from the surfaces by monochloramine disinfection. Free chlorine residual of 2.0 mg/L was found to be effective in biomass removal. However, biofilm level as low as $10CFU/cm^2$ of attached HPC and $5{\mu}g/cm^2$ of biomass still remained on the surfaces at 2.0 mg/L of chlorine residual. The measurement of biomass appeared to be a useful means in evaluating the characteristics of biofilm removal.

• Journal of Conservation Science
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• v.26 no.4
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• pp.397-406
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• 2010

The most ideal method to measure the water-soluble $Cl^-$ ion eluted from iron artifacts is conducting the analysis on desalting solution by Ion Chromatography. But most institutes related to cultural heritages use Cl meter by reason of lack of budget and experts. This study evaluated reliability and stability between Cl meter and Ion Chromatography by doing cross-validation with results from two methods to detect $Cl^-$ ion of desalting solution. From D.I water, extremely small quantities of $Cl^-$ ion was detected by the influence of remaining water-soluble $Cl^-$ ion at the electrode of Cl meter and water-soluble $Cl^-$ which remains in Sodium sesquicarbonate, components of reagent was detected as well. The first desalting solution had the most $Cl^-$ ions, $Cl^-$ ion slightly decreased from the second to the fourth desalting solution and tend to decrease again at the stage of dealkalified in D.I water. Each Cl meter has the standard deviation according to the measured numbers and the higher concentration of $Cl^-$ ion the desalting solution has, the wider the deviation is. But when the concentration of $Cl^-$ ion is low, it was stable to use Cl meter to detect the concentration of $Cl^-$ ion from iron artifacts because there is the small deviation, It is thought that conductivity meter method is not suitable for measuring $Cl^-$ ion, because the electrical conductivity of alkaline solution is too high to measure $Cl^-$ ion.