Journal of Korean Society on Water Environment (한국물환경학회지)

Korean Society on Water Environment (한국물환경학회)
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Effects of Sludge SVI and Chemical Conditioning on Activated Sludge Flotation Thickening

슬러지 SVI와 화학적 개량이 슬러지부상농축에 미치는 영향

  • Lee, Ki Yong (Water Environment Research Department, National Institute of Environmental Research) ;
  • Kim, Shin Jo (Water Environment Research Department, National Institute of Environmental Research) ;
  • Kwon, Oh Sang (Water Environment Research Department, National Institute of Environmental Research) ;
  • Yeom, Ick Tae (Civil & Environmental Engineering Department, Sungkyunkwan University)
  • 이기용 (국립환경과학원 물환경제어연구과) ;
  • 김신조 (국립환경과학원 물환경제어연구과) ;
  • 권오상 (국립환경과학원 물환경제어연구과) ;
  • 염익태 (성균관대학교 사회환경시스템공학과)
  • Received : 2010.01.19
  • Accepted : 2010.02.05
  • Published : 2010.03.30
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Abstract

Electroflotation (EF) was conducted for activated sludge thickening to investigate the effects of sludge SVI (sludge volume index) and chemical conditioning. Return sludge samples were used for the experiment, which were collected from municipal wastewater treatment plants. The performance of sludge thickening was significantly dependent on sludge SVI. For the sludges with SVI values in a range from 50 to about 150 mL/g, the maximum float content decreased rapidly from 8.4 to 3.5% and flotation compressibility followed the same pattern. In cases of sludges with SVI higher than 150 mL/g, those results showed low content levels without large changes. Gas/solids ratio tended to increase with an increase in SVI. When polyelectrolyte was added into sludges for the conditioning, compressibility increased up to 75% and gas/solids ratio was reduced up to about 35% under the condition of microbubble production rate of 530 mL/h, however, there was no consistent effect of chemical conditioning on the maximum float solids content; some cases were positive but the others negative. It was expected that the optimum dose of electrolyte depends on sludge SVI and an excessive chemical dose causes a performance deterioration of flotation thickening.

Keywords

References

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