Journal of Korean Society of Environmental Engineers (대한환경공학회지)

Korean Society of Environmental Engineers (대한환경공학회)
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Comparative Study on Removal Characteristics of Disinfection By-products by Air Stripping and Flotation Processes

탈기와 부상 공정에 의한 소독부산물의 제거특성에 관한 비교 연구

  • Cha, Hwa-Jeong (Water Work Headguarters, Jeonju City) ;
  • Won, Chan-Hee (Department of Environmental Engineering, Chonbuk National University) ;
  • Lee, Kang-Hag (K-water, Korea Water Resources Corporation) ;
  • Oh, Won-Kyu (Department of Environmental and Chemical Engineering, Seonam University) ;
  • Kwak, Dong-Heui (Department of Environmental and Chemical Engineering, Seonam University)
  • 차화정 (전주시 맑은물사업본부) ;
  • 원찬희 (전북대학교 환경공학과) ;
  • 이강학 (한국수자원공사) ;
  • 오원규 (서남대학교 환경화학공학과) ;
  • 곽동희 (서남대학교 환경화학공학과)
  • Received : 2016.07.01
  • Accepted : 2016.09.12
  • Published : 2016.09.30
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Abstract

It is well known that volatile compounds including disinfection by-products as well as emissive dissolved gas in water can be removed effectively by air stripping. The micro-bubbles of flotation unit are so tiny as microns while the diameter of fine bubbles applied to air stripping is ranged from hundreds to thousands of micrometer. Therefore, the micro-bubbles in flotation can supply very wide specific surface area to transfer volatile matters through gas-liquid boundary. In addition, long emission time also can be gained to emit the volatile compound owing to the slow rise velocity of micro-bubbles in the flotation tank. There was a significant difference of the THMs species removal efficiency between air stripping and flotation experiments in this study. Moreover, the results of comparative experiments on the removal characteristics of THMs between air stripping and flotation revealed that the mass transfer coefficient, $K_La$ showed obvious differences. To overcome the limit of low removal efficiency of dissolved volatile compounds such as THMs in flotation process, the operation range of bubble volume concentration is required to higher than the operation condition of conventional particle separation.

수중에 용존된 가스뿐 아니라 소독부산물과 같은 휘발성 화합물은 탈기에 의해 효과적으로 제거할 수 있는 것으로 알려져 있다. 탈기공정에 사용되는 미세 기포는 수백~수천 ${\mu}m$이지만 부상 공정의 기포는 수 ${\mu}m$ 정도로 작다. 이에 따라 부상공정에서의 마이크로 기포는 수중의 휘발성 화합물이 대기로 방출될 수 있는 매우 넓은 기-액 비표면적을 제공한다. 또는 마이크로 기포는 상승 속도가 느려서 휘발성 화합물이 방출될 수 있는 긴 체류시간을 갖게 된다. 본 연구에서 일련의 탈기와 부상 실험을 실시한 결과, THMs의 제거율에서 상당히 큰 차이가 있었다. THMs의 물질전달계수 $K_La$ 역시 큰 차이를 보였다. 따라서 부상공정에서 THMs과 같은 휘발성 화합물을 제거하기 위해서는 일반적으로 입자제거를 위하여 적용되는 통상적인 운전범위보다 더 높은 기포체적농도가 필요함을 알 수 있다.

Keywords

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