Journal of Korean Society on Water Environment (한국물환경학회지)

Korean Society on Water Environment (한국물환경학회)
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Optimum Condition for Fluoride Removal Prior to the Application of Struvite Crystallization in Treating Semiconductor Wastewater

Struvite 결정화를 이용한 반도체 폐수처리 시 불소제거를 위한 최적 조건

  • An, Myeong Ki (Department of Environmental Engineering, Chungbuk National University) ;
  • Woo, Gwi Nam (Han Yang Construction. CO.,LTD) ;
  • Kim, Jin Hyung (D.S Biocleantech CO.,LTD) ;
  • Kang, Min Koo (Department of Environmental Engineering, Chungbuk National University) ;
  • Ryu, Hong Duck (Department of Environmental Engineering, Chungbuk National University) ;
  • Lee, Sang-Ill (Department of Environmental Engineering, Chungbuk National University)
  • 안명기 (충북대학교 공과대학 환경공학과) ;
  • 우귀남 (한양 종합 건설) ;
  • 김진형 (D.S 바이오 크린택) ;
  • 강민구 (충북대학교 공과대학 환경공학과) ;
  • 류홍덕 (충북대학교 공과대학 환경공학과) ;
  • 이상일 (충북대학교 공과대학 환경공학과)
  • Received : 2009.07.21
  • Accepted : 2009.08.27
  • Published : 2009.11.30
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Abstract

This study was aimed to both enhance the fluoride removal and to reduce the phosphorus removal in treating semiconductor wastewater using $Ca(OH)_2$ at low pH so as to facilitate struvite crystallization reaction. The struvite crystallization could be introduced after fluoride removal by retaining the phosphorus source. As the results, the method applied in this study achieved high fluoride removal efficiency (about 91%) with retardation of phosphorus removal at pH 4, compared to conventional methods where the removal of fluoride and phosphorus were done at pH 11. Therefore, the fluoride removal at low pH would contribute to the enhancement of nitrogen and phosphorus removals in a consecutive struvite crystallization reactor. Treatment of semiconductor wastewater at low pH using $Ca(OH)_2$ also had lower (about 20%) water content of precipitated sludge compared to conventional method. As the molar ratio of Ca to F increased the removal efficiencies of fluoride and phosphorus increased. Although the amount of seed dosage didn't affect the removal of fluoride and phosphorus, its increase reduced the water content of precipitated matter. Finally, considering consecutive struvite reaction, the optimum condition for the removal of fluoride and phosphorus was as follow: pH: 4, the molar ratio of Ca:F: 1:1.

Keywords

Acknowledgement

Supported by : 환경부

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