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교반속도 및 Baffle 각도 조절에 따른 침전지 효율 최적화 연구

A Study on the Optimization of Sedimentation Efficiency through Controlling Stirring Speed and Baffle Angle

  • 곽성근 (도화엔지니어링 플랜트부) ;
  • 김충곤 (고등기술연구원 바이오자원순환센터)
  • 투고 : 2020.12.10
  • 심사 : 2020.12.14
  • 발행 : 2020.12.30

초록

본 연구에서는 원형침전지의 고액분리 효율을 향상시키기 위해 응집제 없이 lab scale 침강장치에 교반속도(rpm)와 baffle 각도를 조절하여 생응집(bio-flocculation) 실험을 수행하였다. 피드 웰(feed wall)부분을 개량하여 baffle를 설치하고 각도(10°)를 고정한 후 각각의 교반속도(0.0rpm, 0.6rpm, 1.2rpm) 변화에 따른 실험 결과 교반속도 0.6ppm에서, 농축효율이 2.0%, 유출수(SS 농도) 제거효율은 7.8% 상승되는 것으로 분석되어 교반속도에 따른 슬러지의 생응집 효율 향상을 확인할 수 있었다. 또한, 침강장치 baffle의 각도를 변화시켜 슬러지 침강특성 영향을 분석한 결과 baffle 각도 20°에서 슬러지 계면층의 압축이 매우 높게 나타났다. 본 연구결과는 원형침전지의 침전 효율향상을 위한 기초 인자로 활용이 기대된다.

This study was conducted to improve the solid-liquid separation efficiency of clarifiers. To do so, the study did a bio-flocculation experiment simply by controlling the stirring speed (rpm) and baffle angle of a clarifier on a lab scale, but without using a coagulant. For the purpose of the experiment, the feed wall of a clarifier was so improved that a baffle could be installed on the clarifier. Then, it was ensured to change its stirring speed (to 0.0rpm, 0.6rpm, and 1.2rpm), with the angle fixed at 10°. As a result, it was found that concentration efficiency increased by 2.0%, and effluent removal efficiency (SS concentration) by 7.8%, at a stirring speed of 0.6ppm. This indicates the bio-coagulation efficiency of sludge increased with changing stirring speeds. Then, the baffle angle of the sedimentation unit was changed to analyze how the changed baffle angle would affect the sedimentation of sludge. As a result, it was found that the compression of sludge interface was very effective at a baffle angle of 20°. It is hoped that these experimental findings will be useful in improving the sedimentation efficiency of circular clarifiers.

키워드

참고문헌

  1. Jang, H. G., Cho, Y. M. and Kim, C. W., "Evaluation of water treatment characteristics at the improved circle secondary settling basin", Journal of Korean Society Water and Wastewater, 28(5), pp. 609-614. (2014). https://doi.org/10.11001/jksww.2014.28.5.609
  2. Kim, Y. C., Lee, J. W. and Kang M. G., "Morphological Parameters of the Sludge Flocs in a Long Rectangular Secondary Settling Tank", Journal of Korean Society on Water Quality, 22(3), pp. 468-474. (2006).
  3. So, S. H., Lee, B. H., Park, J. H., Cha, H. Y., Kim, H. S. and Song, K. G., "Improvement of dewaterability and settleability of sewage sludge using coagulation sludge", Journal of the Korean Society of Water and Wastewater, 32(2), pp. 89-96. (2018). https://doi.org/10.11001/jksww.2018.32.2.089
  4. Lee, H. K., "A Study on the Settling Characteristics of Domestic Wastewater", Journal of the Korean Society of Environmental Technology, 14(3), pp. 190-197. (2013).
  5. Lee, B. H., "Evaluation of bioflocculation and settling characteristics for MLSS from a Biological Nutrient Removal Plant", Journal of Korean Society of Water and Wastewater, 22(2), pp. 219-225. (2008).
  6. Hyun, J. Y., "A Study for the Characteristics of Sewage Bioflocculation and Settling in the Secondary Sedimetation Basin", University of Incheon, M.S. Thesis, p. 2, (2009).
  7. Rhu, D. H. and Chio, E. S., "Evaluation of Solids Loading Rates Concerned with Activated Sludge Settling Characteristics in Secondary Clarifier", KSCE Journal of Civil Engineering, 20(4), pp. 599-605, (2000).
  8. Dupont, R. and Dahl, C., "A one-dimensional model for asecondary settling tank including density current and short-circuiting", Wat. Sci. Tech., 31(2), pp. 215-224. (1995). https://doi.org/10.1016/0273-1223(95)00194-R
  9. Korea Ministry of Enviroment, Sewerage facility standards, (2011).
  10. Kim, S. P. and Kim, Y. K., "Sedimentation Assesment of Sludge for Reduction Measuring Time and Volume of Device in SVI", KSWST Journal of Water Treatment, 24(5), pp. 49-58. (2016).