• Journal of Korean Society on Water Environment
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• v.20 no.3
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• pp.275-280
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• 2004

This study was performed to investigate the disinfection efficiency and the formation characteristics of disinfection by-products(DBPs) by chlorination in the sewage effluent. The effluent was sampled from the sewage treatment plants operated in the activated sludge process and the advanced sewage process. The type of DBPs investigated were Trihalomethanes(THMs), Dichloroacetonitrile(DCAN), Chloral hydrate(CH), Dichloroacetic acid(DCAA), Trichloroacetic acid(TCAA). Major findings are as follows. First, the optimum injection concentration for chlorination in sewage effluent were found to be in the range $0.5{\sim}1.0mg\;cl_2/L$. Also, It was found that the chlorine dosage in the effluent of activated sludge process was higher than in the effluent of advanced sewage process. Second, the maximum formation concentration of THMs were $12.7{\mu}g/L$. The THMs formation reaction was finished in a short time of several seconds and chloroform was mainly formed. Also, it was found that the concentration of ammonium nitrogen is higher, the concentration of THMs is lower. Third, it was found that DCAA and TCAA were mainly formed as DBPs by disinfection.

• Journal of Korean Society on Water Environment
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• v.25 no.4
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• pp.553-559
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• 2009

Currently, small scale sewage works are getting increase in Chung Nam Province and it is strongly required for those plants to get the information of optimized procedures and technologies. Most processes for sewage works in Korea were designed for large scale plants, so many difficulties are observed in small scale sewage works. This study was conducted to evaluate the propriety of O&M and construction cost for sewage treatment plants in Chung Nam Province. The treatment results and process stability of 32 public sewage treatment plants were also investigated. It is expected to provide optimum O&M and construction cost for future small scale sewage works and improving projects of existing plants by these results. Pollution problems caused by small scale plants are usually restricted to small areas; however, in view of the high cost per unit population, treatment requirements and alternatives have to be studied carefully. In comparison to larger plants, more pronounced and different boundary conditions such as unstable influent load, per capita costs and a large variety of feasible treatment and disposal systems were considered.

• Journal of Korean Society of Water and Wastewater
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• v.26 no.4
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• pp.565-578
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• 2012

Integrated watershed sewage works program(IWSWP) is defined as implementing, by one of local governments or central government, sewage facilities planning, installation and management for a certain watershed in which criteria of water quality is established and two or more local governments are involved. It is shown that IWSWP is more efficient for the improvement of water quality of water body than conventional local sewage works program(CLSWP) and besides, economical benefits can be achieved by integration of facilities and M&O. In this research, case study for 8 watershed area were investigated to evaluate the difference of effect between IWSWP and CLSWP. The research shows that IWSWP has the money saving result of approximately 12 % by cost reduction for sewage works investment. B/C analysis result shows that B/C ratio of IWSWP was 1.749 and it is higher than B/C ratio of 1.439 for CLSWP. At the same time, the B/C sensitivity analysis is carried out for the rate of discount and the recreational use benefit.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.6
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• pp.877-884
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• 2011

Although peak loading coefficient is one of critical design factors for sewer works, its detailed affecting factors were not analyzed because of limited data availability. This study analyzed the affecting factors on peak loading coefficient with plenty data obtained from several newly constructed sewer works. Simple and multiple regression analysis methods were adopted to analyze the relationships of each variable with or without data filtering. Drainage population, drainage area, population density, and daily sewage flow per person showed very weak relationships under diverse characteristics of cities. However, daily sewage flow per person showed stronger relationships with peak loading when daily sewage flow per person was splitted into two ranges. Population density (i.e., drainage population divided by drainage area) and daily sewage flow per person considerably were related with peak loading coefficient when daily sewage flow per person is less than about 400 Lpcd.

• 수도
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• v.23 no.5 s.80
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• pp.3-12
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• 1996

• 수도
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• v.22 no.5 s.75
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• pp.64-75
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• 1995

• Journal of Korean Society on Water Environment
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• v.24 no.6
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• pp.641-650
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• 2008

This paper reviews the infrastructure of the water supply and sewerage system in North Korea. North Korean has similar legal protection to preserve water environment that can be seen in Republic of Korea, but North Korean regulations seemed lack of detailed measures. The critical pollution problems of rivers and lakes in the northern part of peninsula is mainly due to the lack of sewage collection system and poor treatment works. It has been estimated that less than 20% of sewers are connected to the wastewater treatment plants. Although the availability of water resources seemed sufficient, North Koreans suffer the lack of the drinking water supply which needs an urgent attention. Based on the analysis, it has been suggested that the reconstruction of North Korean water and sewage infrastructure needs at least 17.5 trillion Korean Won.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1997.10a
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• pp.576-579
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• 1997

In order to repair sewage pipes, it is necessary to dig up the damaged sewage pipes, which results in traffic jams. Since digging up the pipes takes too much time and cost, this method is inefficient. So, in stead of digging up the damaged pipes, a robot is sent down to the pipe to do the repair works. For big pipes, human workers go into the pipe and do to repair works, but for small pipes, it is impossible for human worker to go inside the pipe. In this case, mobile robots have used. The procedures for repairing pipes are as follows : First, the condition of the sewage pipes is observed by a robot. Second, appropriate steps for repair are determined according to the types of the damage. While repairing procedures, a newly-developed packer is sent into the sport to be repaired inside the pipe. Then, the packer is filled with air by a V-shaped wrinkel pipe. This makes the packer inflates uniformly and adhere closely to the inside wall of the pipe in large area. This increases the area that can be repaired. Therefore, the newly-developed packer will be very helpful for sewage pipe repair works.

• 수도
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• s.64
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• pp.13-18
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• 1993

• 수도
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• v.23 no.5 s.80
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• pp.54-59
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• 1996