Journal of Korean Society on Water Environment (한국물환경학회지)

Korean Society on Water Environment (한국물환경학회)
권호 표지

Morphological Parameters of the Sludge Flocs in a Long Rectangular Secondary Settling Tank

장방형 침전지에서 길이에 따른 슬러지 floc의 형태에 관한 연구

  • Kim, Youngchul (Dept. of Environmental Engineering, Hanseo University) ;
  • Lee, Jin-Woo (Dohwa Consulting Engineers Co. Ltd) ;
  • Kang, Min-Gi (Dept. of Environmental Engineering, Hanseo University)
  • 김영철 (한서대학교 환경공학과) ;
  • 이진우 ((주) 도화종합기술공사 수도부) ;
  • 강민기 (한서대학교 환경공학과)
  • Received : 2005.10.12
  • Accepted : 2006.02.27
  • Published : 2006.05.30
Download PDF
⟨ Previous Next ⟩

Abstract

In the secondary settling tanks, three different types of settling phenomena occurs; i.e., zone settling for sludge thickening in the bottom part of settling tank, and discrete and flocculent settling for clarification in the upper part. In this paper, morphological parameters of the floc in sludge blanket layers along the length of a long rectangular tank were investigated. The plant used for this study had a serious bulking problem caused by Microthrix parvicella. Floc size decreased as the surface area of settling tank increases, which indicates that in the secondary settling tank where zone settling believed to be predominant, free or flocculent type of settling contributes to floc size distributions. Large floc particles deposit in the front zone of settling tank, but small and loose flocs mostly in the zone near its outlet. On the other hand, filament length contained in one gram of sludge blanket solid increases along the flow direction. Large flocs with less filaments settle faster, but small flocs having more filaments result in poor settling. These results support function of microorganism selection occurring in secondary settling tank. In addition, designing a long rectangluar settling tank with double hoppers might be one of the ways of bulking control, but this idea has to be verified with a further study.

Keywords

References

  1. 강민기, 김영철, 방성호, 이진우, 하준수, Microthrix parvicella에 의한 슬러지 벌킹과 거품문제 해결, 대한환경공학회지, 심사 중 (2006)
  2. 이진우, 김영철, 2차 침전지의 효율개선 및 개량방안, 대한토목학회지, 53(8), pp. 88-94 (2005)
  3. 정팔진, 조선영, 정진필, 이은주, 슬러지의 선택적 분리를 위한 침전지의 직렬운전에 관한 연구, 한국물환경학회지, 19(6), pp. 615-622 (2003)
  4. 한국상하수도협회, 하수도시설기준, 건설도서, p. 382 (2005)
  5. Andreadakis, A., Physical and Chemical Properties of Activated Sludge Floc, Water Sci. Technol., 27(12), pp. 1707-1714 (1993)
  6. Giokas, D. L., Kim, Y., Paraskevas, P. A., Paleologos, E. K. and Lekkas, T. D., A Simple Empirical Model for Activated Sludge Thickening in Secondary Clarifiers, Water Research, 36(13), pp. 3245-3252 (2002) https://doi.org/10.1016/S0043-1354(02)00019-2
  7. Giokas, D. L., Daigger, G. T., von Sperling, M., Kim, Y. and Paraskevas, P. A., Comparison and Evaluation of Empirical Zone Settling Velocity Parameters Based on Sludge Volume Index Using an Unified Settling Characteristics Database, Water Research, 37(16), pp. 3821-3836 (2003) https://doi.org/10.1016/S0043-1354(03)00298-7
  8. Hao, O. J., Strom, P. F. and Wu, Y. C., A Review of the Role of Nocardia-like Filaments in Activated Sludge Foaming, Water SA, 14, pp. 105-110 (1988)
  9. Jenkins, D., Richard, M. and Daigger, G., Manual on the Causes and Control of Activated Sludge Bulking and Foaming, Ridgeline Press, Lafayette, CA, pp. 33-78 (1986)
  10. Kim, Y., Pipes, W. O. and Chung, P. G., Estimation of Susepended Solids Concentration in Activated Sludge Settling Tanks, Water Sci. Technol., 35(8), pp. 127-135 (1997) https://doi.org/10.1016/S0273-1223(97)00159-5
  11. Kim, Y., Pipes, W. O. and Chung, P. G., Control of Activated Sludge Bulking by Operating Clarifiers in a Series, Water Sci. Technol., 38(8-9), pp. 1-9 (1998)
  12. Madoni, P., Davoli, D. and Gibin, G., Survey of Filamentous Microorganisms from Bulking and Foaming Activated Sludge Plants in Italy, Water Research, 34(6), pp. 1767-1772 (2000) https://doi.org/10.1016/S0043-1354(99)00352-8
  13. Mazzolani, G., Pirozzi, F. and d'Antonoi, G., A Generalized Settling Approach in the Numerical Modeling of Sedimentation Tanks, Water Sci. Technol., 38(3), pp. 95-102 (1998)
  14. Metcalf & Eddy, Waterwater Engineering Treatment, Disposal, and Reuse, 4th Edition, McGraw-Hill, p. 834 (2003)
  15. Pipes, W. O., Types of Activated Sludge Which Separates Poorly, Presented at the 40th Annual Meeting of the Central States Water Pollution Control Association, p. 714 (1969)
  16. Pipes, W. O., Bulking of Activated Sludge Processes, in Advances in Applied Microbiology, Academic Press, New York, 9, pp. 185-234 (1979)
  17. Pujol, R., Duchene, P., Schetrite, S. and Canler, J. P., Biological Foams in Activated Sludge Plants: Characterization and Situation, Water Research, 25, pp. 1399-1404 (1991) https://doi.org/10.1016/0043-1354(91)90118-A
  18. Sezgin, M., Jenkins, D. and Parker, D. S., A Unified Theory of Filamentous Activated Sludge Bulking, Journal WPCF., 50, p. 362 (1978)
  19. Vesilind, P., Design of Prototype Thickners from Batch Settling Tests, Water Sewage Works, 115, pp. 302-307 (1968)
  20. WEF and ASCE., Design of Municipal Wastewater Treatment Plants, I, WEF/ASCE, New York, NY, p. 450 (1992)