• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.4
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• pp.594-601
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• 2021

In order to expanding of the use of steel slag, a by-product of steel industry, as a road paving construction material, this present study confirmed the possibility of the rust formation of steel slag aggregate and evaluated the durability performance and the noise reduction characteristics of asphalt concrete mixture. As a result of conducting the rust formation test of aggregate, no rust was observed in both aggregate, so it is judged that the possibility of rust formation in the actual road water environment is very low. As a result of performing the moisture resistance test, all mixtures showed a tensile strength ratio exceeding 85%, satisfied the standard as asphalt mixture. In addition, the sound absorption coefficient of the steel slag aggregate mixture was measured to be higher than that of the general aggregate mixture. Accordingly, it is speculated th at th e steel slag aggregate mixture can more effectively respond to road noise reduction than the general mixture.

• 월간 기계설비
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• s.116
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• pp.71-73
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• 2000

• Journal of Korean Society of Water and Wastewater
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• v.19 no.2
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• pp.228-237
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• 2005

The main purpose of this study was to investigate the red water reducing effects of phosphate based inhibitor when it was applied to water distribution system. The effects of pH, alkalinity, calcium concentration in the reduction of the red water also studied. The most finished water in Korea showed relatively high corrosiveness and was required to introduce some types of corrosion reducing methods such as addition of alkalinity. The precipitation of $CaCO_3$ by addition of $Ca(OH)_2$ formed porous film on the surface of the carbon steel pipes and was displaced easily from the surface of the pipes; on the other hand, addition of zinc phosphate (ZOP) formed reliable film on the surface and reduced iron release and color. Although the main function of ZOP was to suppress the release of Pb and Cu, it also reduced iron concentration released from water distribution pipes.

• 월간 기계설비
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• no.12 s.209
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• pp.34-43
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• 2007

환경부는 산하 수처리선진화사업단에서 수돗물 수질개선대책의 일환으로 연구개발한 옥내급수관 진단, 세척 및 갱생기술을 적용, 서울시와 공동으로 시범사업을 실시한다고 밝혔다. 이 사업은 서울 둔촌동 주공아파트 2개동 80세대를 대상으로 약 1억2000만원의 예산을 들여 지난 8월 말부터 시행, 수돗물 녹물발생 방지를 위한 갱생기술의 완성도를 검증·확인한다는 것. 기존 옥내급수관 갱생기술은 평균 관직경 15mm인 소형관에 대한 정밀시공이 어려워 녹이 재발하는 경우가 많았다. 하지만 이번에 개발된 기술은 수도관 내부의 녹 제거 및 관 내부 표면이 균일토록 코팅할 뿐 아니라 시공 후 마이크로 로봇을 이용, 관 내부 촬영 및 절연도 체크를 통해 코팅 완성도를 확인, 녹 재발 가능성을 미연에 방지한다. 이번 기술이 검증되면 환경부는 선박배관, 빌딩, 냉각수배관, 소화용배관, 산업용배관 등에도 확대 적용하고 해외진출을 통해 물산업 육성 아이템으로 발전시킬 계획이다. 한편 환경부는 지난 2005년 수도법을 개정, 건축연면적 6만$m^2$이상 다중이용건축물과 연면적5,000$m^2$이상 국.공립 공공시설은 준공 5년 후부터 매년 수질검사를 실시, 결과에 따라 수도관을 세척·갱생 또는 교체토록 올해 1월부터 의무화 하고 있다.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.1
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• pp.97-106
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• 2012

To investigate the application of corrosion inhibitor on water supply pipes, turbidity, magnitude of corrosion, composition of scale and concentration of metals from an old steel pipe were analysed under inhibitor addition. The concentration of turbidity, iron and copper from the pipes under inhibitor application was 12 ~ 14% of the case which no inhibitor was applied, which suggests the application of inhibitor was very effective for internal corrosion control. In addition, SEM, EDX, XRD and XRF test results showed that application of inhibitor was effective for the decrease of iron concentration and increase of oxygen, phosphorus and calcium concentration, which suggested the existence of protective layer. Therefore, the occurrence of red water will be significantly decreased when inhibitor was applied to the old steel pipes.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.839-846
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• 2011

To investigate corrosivity characteristics of raw water in Korea, Langelier index (LI) of 30 multi-regional water treatment plants (WTPs) were evaluated. Annual average values of LI at 30 WTPs were all negative, which means raw water in Korea is very corrosive. LI results for 4 major rivers showed that raw water from Han and Nakdong had relatively high values compared to those of Sumjin and Keum. On the other hand, LI values of raw water from the tributaries of four major rivers were relatively low presumably due to geological characteristics, and in some cases the values were less than -4.0 which means increase of LI is urgently needed to minimize red water problem. Based on the correlation results among LI and water quality parameters, pH, water temperature, calcium concentration were confirmed as major components for LI. Therefore, pH and calcium concentration control is an effective method for the improvement of LI in water treatment processes.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.864-868
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• 2008

Water transmission and distribution systems play a important role to deliver safe and clean water and are responsible for the most direct impacts of water utilities to customers. Although the performance of WDS(Water Distribution Systems) should be evaluated by a certain standards, interests has not been in WDS and developed due to invisible, hard-working and insufficient information in the evaluation process in Korea till now. The investigations and researches were carried out to develop software to assist the evaluation of WDS with respects to hydraulics, water quality and structural analysis methods. The methodologies have been developed which can be used to estimate the performance to water distribution network and software are implemented by the process. Developed systems are consisted with database, analysis techniques, simulation models, decision support systems and other tools. The concepts and functions are introduced in this paper and the performance index are discussed for accurate assessment of water distribution systems.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.3
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• pp.313-324
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• 2011

Several complaints from consumers on red or turbid waters were often filed at the same places although various efforts were made to improve water quality in the drinking water plant. The red water problems were occurred due to corrosion of main water pipe, especially at extremity. The low concentrations of chlorine indicating poor water quality were detected at the problematic location. To solve the poor water quality at the extremity, flushing techniques, i.e., conventional flushing, unidirectional flushing, and continuous flushing, were recently practiced. In this study, effects of conventional flushing on water qualities were examined by comparing turbidity and residual chlorine before and after flushing. In addition, more detailed analyses on water qualities at the tap water were conducted to learn a reduction pattern during flushing. Five items from geographic information system of water distribution were used to obtain a relationship with water quality, washing duration or amounts of washing water. The flushing was effective to meet the National Drinking Water Quality Standard with simple and relatively short time operation. The key operational parameter in flushing was amounts of washing water which should be estimated based on water quality of the consumer's tap water. The positive relationship between the residual chlorine and pipe length implied that detention time in the pipeline was the main cause of the complaints. More experiments on effectiveness of flushing are needed to determine reasonable strategies of flushing.