Journal of Korean Society of Water and Wastewater (상하수도학회지)

The Korean Society of Water and Wastewater (대한상하수도학회)
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Comparison of infiltation rate for separate sewer system and combined sewer system in sewer maintenance areas

하수관로정비 지역의 분류식과 합류식 하수관로의 침입율 비교

  • Gu, Gwangmo (Department of Environmental Engineering, Daejeon University) ;
  • Chu, Shaoxiong (Department of Environmental Engineering, Daejeon University) ;
  • Lim, Bongsu (Department of Environmental Engineering, Daejeon University)
  • Received : 2020.02.10
  • Accepted : 2020.05.10
  • Published : 2020.06.15
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Abstract

This study is to improve the efficiency of BTL (Build Transfer Lease) project operation by comparing the infiltration rate based on the data of 5 years of infiltration of the separate sewer system and combined sewer system. In the survey site, the separate sewer system area consists of eight flowmeters in seven treatment basins, and the combined sewer system area consists of eight flowmeters in five treatment basins. The infillration rate was analyzed by night-time domestic flow evaluation method, and the average infiltration rates of the separate sewer system and combined sewer system were 13% and 16%, respectively. Combined sewer system was about 1.3 times higher than the separate sewer system. The average BOD of separate sewer system was 233 mg/L, which was about 2.4 times higher than the combined sewer system was 107 mg/L. In the comparison of the average pipe diameter-length infiltration of separate sewer system and combined sewer system, the separate sewer system and the combined sewer system were about 0.150 ㎥/d/mm/km and about 0.109 ㎥/d/mm/km, respectively. The floating population in mixed residential and commercial areas has been identified as the cause. Therefore, we propose a method to calculate the infiltration rate in consideration of the margin ratio in the area where the night active population is concentrated.

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References

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