Improvement of Water Treatment Efficiency by pH Decreasing Agent (H2SO4) for Droughty Seasons

갈수기 정수장운영관리 사례 - 갈수기 pH저감제(황산)투입에 의한 정수처리효율 향상

  • Ka, Gilhyun (Yeongdeungpo Water Supply Office) ;
  • Kim, Yunyung (Yeongdeungpo Water Supply Office) ;
  • Lee, Junho (Yeongdeungpo Water Supply Office) ;
  • Ahn, Chihwa (Yeongdeungpo Water Supply Office) ;
  • Han, Ihnsup (Department of Environmental Engineering, University of Seoul) ;
  • Min, Byungdae (Department of Environmental Engineering, University of Seoul)
  • 가길현 (서울시 영등포아리수정수센터) ;
  • 김윤용 (서울시 영등포아리수정수센터) ;
  • 이준호 (서울시 영등포아리수정수센터) ;
  • 안치화 (서울시 영등포아리수정수센터) ;
  • 한인섭 (서울시립대학교 환경공학부) ;
  • 민병대 (서울시립대학교 환경공학부)
  • Received : 2008.04.15
  • Accepted : 2008.06.16
  • Published : 2008.07.30

Abstract

Drinking water treatment is enhanced by coagulant dosages and chlorine injection because of pH increase in raw water in droughty seasons such as spring and fall. But water quality deterioration is occurred by increase in residual aluminium and disinfection by-products. Coagulation process can be used to control natural organic matter (NOM) during water treatment. The effect of coagulation process appeared to depend on the pH of water rather than coagulant dosages. In this study, for water treatment in high pH season $H_2SO_4$ was applied for pH adjustment at full scale. Before and after pH adjustment by $H_2SO_4$ injection, water quality of drinking water was evaluate. In the result of investigation of total organic carbon (TOC) removal in high pH season, TOC was removed approximately 30~40%, which showed decrease in water treatment efficiency. Also, it is increased both particle numbers and residual Al concentration in the water. After $H_2SO_4$ injection for adjustment to pH<7.5 in settled water, treated water turbidity decreased in 0.047 NTU from 0.059 NTU, and particle numbers of filtered water decreased in 20/mL from 90/mL. On the other side, TOC removal efficiency increased in approximately 10% after adjustment of pH. In the result of decrease in pH in raw water through more coagulants and prechlorine without $H_2SO_4$ injection, trihalomethanes (THMs) concentration increased in $16{\mu}g/L$ from $8{\mu}g/L$.

Keywords

Acknowledgement

Supported by : 서울시립대학교

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