Journal of Korean Society of Environmental Engineers (대한환경공학회지)

Korean Society of Environmental Engineers (대한환경공학회)
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Enhancement of Dewaterability of Sewage Sludge by Ultrasonification and Electric Field Treatment

초음파와 전기장 처리에 의한 하수슬러지 탈수성 향상

  • Mo, Woojong (Department of Environmental Engineering, Inha University) ;
  • Han, Jisun (Department of Environmental Engineering, Inha University) ;
  • Ahn, Changmin (Department of Environmental Engineering, Inha University) ;
  • Yoon, Soonuk (Department of Environmental Engineering, Inha University) ;
  • Seok, Heejung (Department of Environmental Engineering, Inha University) ;
  • Kim, Changgyun (Department of Environmental Engineering, Inha University)
  • 모우종 (인하대학교 환경공학과) ;
  • 한지선 (인하대학교 환경공학과) ;
  • 안창민 (인하대학교 환경공학과) ;
  • 윤순욱 (인하대학교 환경공학과) ;
  • 석희정 (인하대학교 환경공학과) ;
  • 김창균 (인하대학교 환경공학과)
  • Received : 2012.05.02
  • Accepted : 2012.11.23
  • Published : 2013.01.30
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Abstract

The sludge disposal is a major economic factor in the sewage treatment facility operation. Moreover, since the ocean dumping will be prohibited by Korean environmental law from 2013, sludge should be eliminated or sludge volumetric reduction should be performed urgently. In this study, improvement of the sewage sludge dewaterability was investigated by ultrasound and electric field treatment. Sludge was treated by a single or in combination of either the electric field or ultrasound on a pilot pretreatment facility, then it was dewatered by lab-scale filter press. The operating input energy of ultrasound device was varied from 225~1,200 kJ/L and electric field device was varied from 4.5~24 kJ/L. The water contents of dewatered sludge cake treated with ultrasound (1,200 kJ/L) and combination of ultrasound/electric field (1,224 kJ/L) were decreased 10~12% by comparing non-treated sludge. At that time, water contents were 65~66%. The combination treatment of ultrasound/electric field was effective to reduce water content of dewatered sludge cake, however, water content was not changed by a single treatment of electric field because of low energy density.

슬러지 처분비용은 하수처리장 운영에 있어서 중요한 경제적 요소이다. 더욱이, 2013년부터 유기성 폐기물의 해양투기가 금지되면서 대부분의 슬러지가 육상 처리 되어야 하기 때문에 슬러지의 발생량을 줄이는 것이 시급한 상황이다. 본 연구에서는, 초음파와 전기장 처리에 의한 하수슬러지의 탈수성 향상을 확인하고자 하였다. 슬러지는 pilot-scale의 전처리 장치로 초음파와 전기장 단독처리 그리고 초음파 및 전기장 병합처리 되었으며, 처리 후 lab-scale 필터프레스 장치로 탈수되었다. 실험한 초음파 에너지 밀도 범위는 225~1,200 kJ/L였고 전기장 처리장치는 4.5~24 kJ/L였다. 초음파 단독처리와 초음파 및 전기장 병합처리 된 슬러지의 탈수 cake 함수율은 에너지 밀도 1,200 kJ/L일 때, 처리하지 않은 슬러지보다 각각 10~12% 감소하였으며 이 때 슬러지 함수율은 65~66%였다. 초음파 및 전기장 병합처리가 초음파 단독처리보다 탈수된 슬러지 cake의 함수율을 낮추는데 효과적이었으나, 전기장 단독처리의 경우 에너지 밀도가 낮아 함수율의 변화는 거의 없었다.

Keywords

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  1. Dewaterability Improvement and Volume Reduction of Bio-Solid using Ultrasonic Treatment vol.15, pp.6, 2014, https://doi.org/10.5762/KAIS.2014.15.6.4019