• Journal of Korean Society of Water and Wastewater
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• v.29 no.6
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• pp.659-666
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• 2015

In this study, Hazen-Williams C value of pipes in wide waterworks system was estimated and statistically analyzed. Hazen-Williams C value of water pipe was predicted after 20 years of service period. From the results, it was found that C value of water pipe for treated water maintained higher value of 110 after 20 years of installation. Furthermore, it was found that velocity coefficients of steel pipe for less than and more than 20 years of installation were 117.7 and 109.3, respectively. C value of ductile iron pipe for less than and more than 20 years of installation were 118.1 and 114.2, respectively. In this study, it was also found that small value of C is used in the design of water pipe system. Therefore, excessively bigger size of pipe can be determined in the design of water pipe system. From the results of present study, optimum value of C can be used to avoid the oversized design of water pipe system.

• The KIPS Transactions:PartD
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• v.11D no.6
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• pp.1311-1318
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• 2004

Demand of water is increased according to city centralism phenomenon in population and development. In this progress, guarantee of enough water is important factor for water supply policy. For the detection of exact water leakage point, an epochal sensing technique using computer and internet is required, so, the water pipe having sensing wire and sensing technology using TDR(Time Domain Reflectometer), is proposed in this paper. For the prove of effectiveness of this system, pilot system using 300mm 3-layer coated steel pipe is made and tested.

• Journal of Korea Water Resources Association
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• v.52 no.8
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• pp.555-563
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• 2019

Reduced thickness of the water pipes due to corrosion makes it difficult to perform the original functions since corrosion in metallic water pipes can occur over time. In this study, reliability model that can estimate the probability of pipe breakage is developed regarding corrosion depth increment according to service year. Probability of pipe breakage was calculated by FORM(First Order Reliability Method) and unsteady analysis was performed to analyze the statistical properties of water pressure. And KCIP(Korea Cast Iron Pipe) equation was adopted for the reliability function. Furthermore, change of pipe thickness was estimated by Nahal and Khelif equation and Romanoff equation. Therefore, pipe thickness was calculated due to change of corrosion depth and probability of pipe breakage was calculated and compared with 10, 20, 30 service years. From the results, probability of pipe breakage for network A is gradually increased from 6.8% to 8.6% according to service year of 10, 20, 30 when Nahal and Khelif equation is applied. And probability of pipe breakage for network A is also gradually increased from 6.4% to 8.9% according to service year of 10, 20, 30 when Romanoff equation is applied.

• Journal of Environmental Impact Assessment
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• v.14 no.1
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• pp.17-24
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• 2005

This study was performed to evaluate the adsorption rate of phosphate corrosion inhibitor and reaction rate constant in drinking water distribution systems. The optimum concentration of corrosion inhibitor would vary depending on the quality of water, pipe materials, and condition of metal surfaces. The current adsorption study indicated that the residual phosphate concentration of the corrosion inhibitor decreased with the time as it adsorbed on the surface of pipe material. As time went by, the residual phosphate concentration became constant. It means that the formation of the corrosion protection film on metal surfaces is completed.

• Water for future
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• v.29 no.4
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• pp.223-231
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• 1996

For the most efficient operation of water mains, 124 head losses in domestic water supply steel mains were measured to provide the values of friction coefficient and the variable affecting the deterioration rate of Hazen Williams' and Darcy-Weisbach's friction coefficient. The experimental results show that pipe age is governing the friction coefficient of large mains (Diameter > 1100 mm). On the other hands, pipe age and pipe diameter are affecting the variation of carrying capacity for small mains (Diameter < 1100 mm). The friction coefficient of water mains in foreign countries is higher than that in Korea by about 5 to 10 in Hazen Williams' C value. The growing rate of roughness height of domestic water main is about 0.41 mm/year which is higher than the average of United States of America. So further study is required to find out what causes the serious deterioration rate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.12 no.1
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• pp.545-551
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• 2011

Recently, demands for generating high quality tap waters are increasing with high concern of water pollution and corrosion of water pipelines. For the reasons, developing water quality stabilization technique in water purification system is sought rather than replacing to a new pipelines. In this study, high-purity liquid lime($Ca(OH)_2$) was introduced for a water quality stabilization technique in water purification process and simulated water distribution system of pilot-scale size was applied to evaluate anti-corrosion control effect. The effect of anti-corrosion control was calculated in terms of LSI(Langelier Saturation Index) In conclusion, the result of pilot plant showed improvement of corrosiveness by liquid lime($Ca(OH)_2$) with reduction of released iron(Fe). Application of anti-corrosion control technique to the mild steel coupon and the copper coupon were effective by indicating 35.4, 44.5% of improvements. Besides, sample pipes which were treated with liquid lime had formated more thicker layer of corrosion product inside of pipes. As a result, the process of injecting water stabilizer can greatly contribute to the high quality of tap water.

• Journal of the Korean Geotechnical Society
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• v.30 no.8
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• pp.39-47
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• 2014

Frost heaving and thawing settlement cause unexpected stress around buried pipelines, which results in deformation and permanent demage. A large scale laboratory test has been performed to observe deformation, stress, and temperature of a buried pipe during atmospheric temperature changes. From the experimental results, the stress concentrated around the buried pipe is inevitable and deformation is caused by the frost heaving. Even though backfill materials are sandy soils which are normally assumed to be non frost susceptible, it is revealed that frost demage can happen due to drainage condition, the level of ground water table, and water content.

• Proceedings of the KIEE Conference
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• 2004.11a
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• pp.227-229
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• 2004

The corrosion rate of buried steel pipes for water works was investigated under soil environment. Steel pipe shows various characteristics caused by complicated environment condition of underground and especially the corrosion rate of it depends on the resistivity of soil controlled by content of water. In this paper, the corrosion behavior of steel pipe was observed by polarization test under soil and the silica sand in the water content range of 0-50%. Generally it is well known that the resistivity of soil decreased rapidly over 15% water content. In fact the corrosion rate, corrosion potential, and corrosion consumption (MPY) of steel pipe were shown very different aspects within 20% water content.

• Korean Journal of Environmental Agriculture
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• v.21 no.3
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• pp.208-215
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• 2002

This study was carried out to evaluate the pollutant removal efficiencies of the advanced drinking water treatment using activated carbon process. for raw water, Nakdong river was used. from the activated carbon adsorption experiment the fellowing results were obtained The efficiency of water treatment enhanced with increase in empty bed contact time. Variation of pH was not detected to the bed depth, but DO content gradually decreased with the bed depth. Removal efficiency of $KMnO_4$ consumption, UV254 absorption, DOC and THMFP also were increased by increasing in the bed depth. Transition of adsorption zone from upper parts of the bed to the lower parts were detected as treatment periods increased. Large portion of DOCs were degraded and removed by the microbes growing on the surface of activated carbons. Cell numbers of microbes were estimated over $1.1\times10^7\;cell/cm^3$ at the depth of 20 cm from the surface 126 days after starting operation. The results shown that the activated carbon Inter was successfully acted as a biofilm filter.

• Korean Journal of Environmental Agriculture
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• v.21 no.3
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• pp.189-196
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• 2002

This study was carried out to evaluate the pollutant removal efficiencies of the advanced drinking water treatment using ozonation process. For raw water, Nakdong River was used. By conducting continuous ozonation experiments, the following results were obtained. Efficiency of water treatment was enhanced with increase in ozone dosage. When ozone dosage of 3 mg/L was used, preozonation ot raw water reduced TDOC, ADOC, A &BDOC and NRDOC as much as 0.6 mg/L, 0.2 mg/L, 0.1 mg/L and 1.0 mg/L, respectively. On the other hand, content of BDOC increased at the level of 0.8 mg/L. Ratio of UV254 absorbance to DOC content by the preozonation with 1, 3 and 5 mg/L dosage were 0.048, 0.044 and 0.037, respectively. In case of postozonation, it were 0.018, 0.015 and 0.012, respectively. When the ratios of consumpted ozone content to 1 mg of initial DOC were 1.5 and 2.3 in preozonation and postozonation treatment, respectively, the highest DOC removal rates of 25% and 32% were obtained by the continuous ozonation.