Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
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Characteristic of Mixing and DO Concentration Distribution in Aeration Tank by Microbubble Supply

마이크로버블 공급에 의한 폭기조내 교반과 용존산소 분포 특성

  • Lim, Ji-young (Dept. of Civil & Environmental Engineering, Incheon National University) ;
  • Kim, Hyun-Sik (Dept. of Civil & Environmental Engineering, Incheon National University) ;
  • Park, Dae-Seok (Dept. of Civil & Environmental Engineering, Incheon National University) ;
  • Cho, Young-Gun (Dept. of Civil & Environmental Engineering, Incheon National University) ;
  • Song, Seung-Jun (Dept. of Civil & Environmental Engineering, Incheon National University) ;
  • Park, Soo-Young (Dept. of Civil & Environmental Engineering, Incheon National University) ;
  • Kim, Jin-Han (Dept. of Civil & Environmental Engineering, Incheon National University)
  • 임지영 (인천대학교 건설환경공학과) ;
  • 김현식 (인천대학교 건설환경공학과) ;
  • 박대석 (인천대학교 건설환경공학과) ;
  • 조영근 (인천대학교 건설환경공학과) ;
  • 송승준 (인천대학교 건설환경공학과) ;
  • 박수영 (인천대학교 건설환경공학과) ;
  • 김진한 (인천대학교 건설환경공학과)
  • Received : 2016.03.08
  • Accepted : 2016.05.12
  • Published : 2016.05.31
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Abstract

This study examined the DO concentration distribution and ORP distribution using microbubbles on pilot-scale aeration tanks. As a result of MLSS mixing and oxygen transfer phenomenon using microbubbles, different DO concentrations were observed depending on the circulation of the liquid with the microbubble supply location on the lateral of an aeration tank. The simulation results of CFD (computational fluid dynamics) program showed that MLSS mixed with a microbubble supply in the middle the reactor is much better than on the left side of the reactor. A single reactor containing an anaerobic, anoxic, and aerobic zone, was evaluated without partition according to the location of the microbubble supply based on the experiments and CFD analysis. MLSS was separated into solid-liquid by the microbubble supply in the aeration tank. Consequently, selecting the appropriate microbubble size is important for MLSS mixing and was maintained at the proper DO concentration for biological treatment.

본 연구는 가압식 마이크로버블 발생장치를 이용하여 공기를 마이크로화 시켜 공급하면서 pilot-scale 규모의 폭기조내 DO 농도 및 ORP 변화를 살펴보았다. 마이크로버블에 의한 폭기조 내 교반 및 산소전달 능력을 확인한 결과, 폭기조 횡(橫)방향으로 마이크로버블 공급위치에 따라 폭기조 내액의 순환으로 인하여 단일반응조 내에서 측정위치별 DO 농도가 다르게 나타남을 확인할 수 있었다. 또한, 마이크로버블 공급위치에 따른 교반현상을 파악하고 마이크로버블 공급위치의 적정성을 확인하고자 유체유동해석을 한 결과, 마이크로버블 공급위치가 폭기조 횡(橫)방향으로 1/2지점일 경우, 좌측면에서 공급될 때보다 폭기조 내부의 교반이 잘 이루어져 사영역이 적게 발생되는 것을 확인되었다. 실험 및 유체유동해석 결과를 바탕으로 마이크로버블 공급위치에 따라 단일반응조에서 DO 농도를 변화시켜 격벽이 없는 영역분리가 가능하므로 혐기, 무산소, 호기를 한 공간에서 운영할 수 있는 가능성을 확인할 수 있었다. 마이크로버블을 공급했을 경우, 산기관을 사용할 때와는 다르게 MLSS가 부상농축되는 고액분리 현상이 발생하였는데 마이크로버블이 생물학적 처리를 위하여 부상의 목적이 아닌, MLSS의 혼합과 적절한 DO 농도 유지를 목적으로 사용되기 위해서는 폐수 종류에 따른 적절한 크기의 버블선택이 중요함을 확인할 수 있었다.

Keywords

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