Journal of Korean Society of Environmental Engineers (대한환경공학회지)

Korean Society of Environmental Engineers (대한환경공학회)
권호 표지

Improvement of the Performance of Coagulation-Crossflow Microfiltration Using Inline Injection System

인라인 주입방식을 활용한 응집-정밀여과 공정의 효율향상

Kim,Su-Han;Park, Hee-Kyung
김수한;박희경

  • Published : 20040000
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Abstract

Cake reduction in coagulation-crossflow microfiltration is analyzed using hollow fiber MF module. Kaolin is used as the particle and aluminum sulfate as the coagulant for the experiment. Floc formed by coagulation is broken by pump, but re-aggregates in membrane module. The tendency of floc breakage increases with the increase of particle size. Re-aggregated floc is removed from membrane surface by shear rate and this is the main mechanism of cake reduction in coagulation-crossflow microfiltration. The more floc is re-aggregated, the larger the reduction rate of cake layer is. In charge neutralization condition, the performance of re-aggregation is better than that in sweep flocculation condition. These results mean the rapid mixing that distributes charges to particles efficiently is crucial for the good performance of the coagulation-crossflow microfiltration process. So inline injection system is introduced and proved to be effective for re-aggregation and cake reduction in the process.

Crossflow 방식의 중공사형 모듈을 이용해서 응집-정밀여과의 케이크 층 저감 현상에 대하여 연구하였다. 물질은 카올린, 응집제는 황산알루미늄을 사용하였다. 응집에 의해 형성된 플록은 펌프의 강한 회전력에 의해 깨지지만, 막 모듈 내에서 재응집되어 전단유속에 의해 쉽게 제거된다. 이때, 플록의 깨짐현상은 입자의 크기가 클수록 현저하게 나타난다. 재응집의 정도가 클수록 케이크층 저감량은 크다. Charge neutralization 조건에서의 재응집 효과가 sweep flocculation의 경우보다 좋았다. 이를 바탕으로 급속혼화의 효율을 중시하는 시스템인 인라인주입방식을 도입하였고, 도입 결과, 원수조 내에서 응집시킨 경우보다 재응집 및 케이크 층 저감에서 우수한 결과를 얻었다.

Keywords

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