Investigation on the Hydrodynamic Behaviors of the Clarifier with an Interior Baffle in WWTP by using of Radiotracer $^{99m}Tc$

$^{99m}Tc$ 추적자를 이용한 하수처리 시설 내 침전조의 정류벽 설치 유무에 따른 유체거동 변화측정

  • Kim, Jin-Seop (Korea Atomic Energy Research Institute, Radioisotope Research & Development Center) ;
  • Kim, Jong-Bum (Korea Atomic Energy Research Institute, Radioisotope Research & Development Center) ;
  • Kim, Jae-Ho (Korea Atomic Energy Research Institute, Radioisotope Research & Development Center) ;
  • Jung, Sung-Hee (Korea Atomic Energy Research Institute, Radioisotope Research & Development Center)
  • 김진섭 (한국원자력연구원, 동위원소이용연구센타) ;
  • 김종범 (한국원자력연구원, 동위원소이용연구센타) ;
  • 김재호 (한국원자력연구원, 동위원소이용연구센타) ;
  • 정성희 (한국원자력연구원, 동위원소이용연구센타)
  • Published : 2007.09.30

Abstract

The hydrodynamic behaviors of the clarifier with an interior baffle in a wastewater treatment plant was investigated by using a radiotracer $^{99m}Tc$(30 40 mCi) to verify the results of CFD(computational fluid dynamics) modelling in the previous study. The clarifier model was manufactured with consideration to the hydraulic similarity(1/21) of a real plant($L{\times}W{\times}H:2.6{\times}0.4{\times}0.2m$). By installation of an interior baffle to the clarifier, the strong density current at the bottom of the clarifier decreased substantially and increased the area of sludge settling zone, which were visualized successfully from the radiotracer experiment. Also the portion of short circuit stream changed from 48 % to 32 % and the mean residence time of sludge decreased from 940 sec to 810 sec, which corresponds to the results of CFD modelling. As a result, it is anticipated that radiotracer technology can be used as an important tool for designing new wastewater treatment plants and verifying their performances after structural modifications.

References

  1. 환경부, 런던협약 '96의정서 발효에 따른 하수슬러지관리 종합대책, 2007;1-58
  2. Metcalf & Eddy, Wastewater Engineering Treatment, Disposal, and Reuse, 3rd ed. McGraw-Hill, 1991;445-527
  3. Vestner RJ, Gunthert FW, Influence of sludge properties and hydraulic loading on the performance of secondary settling tanks-full-scale operational results, Water sci. & technol. 2004;50(7):179-186
  4. Krebs P, Success and shortcomings of clarifier modelling, Water sci. & technol. 1995;31(2):181-191
  5. Esler JK, Optimizing clarifier performance, paper presented at 57th Annu. Conf. Water pollut. Control Fed., New Orleans, La. 1984
  6. Parker DS, Kinnear DJ, Gerges, HZ, and Wahlberg EJ, Approach for Diagnosing Secondary clarifier performance problems and prescribing improvements, WEF plant operations specialty conference, 6-9 June, Milwaukee, Wisconsin, USA, 1999
  7. Chmielewski AG, Owczarczyk A, Palige J, Radiotracer investigations of industrial waste water equalizerclarifiers, NUKLEONIKA, 1998;43(2):185-194
  8. Borroto JI, Dominguez J, Griffith J, Fick M, Leclerc JP, Technetium-99m as a tracer for the liquid RTD measurement in opaque anaerobic digester: application in a sugar wastewater treatment plant, Chemical engineering and processing, 2003;42:857-865 https://doi.org/10.1016/S0255-2701(02)00109-5
  9. Kim HS, Shin MS, Jang DS, Jung SH, Jin JH, Study of flow characteristics in a secondary clarifier by numerical simulation and radioisotope tracer technique, Applied radiation and isotopes, 2005;63(4):519-526 https://doi.org/10.1016/j.apradiso.2005.03.016
  10. 한국원자력연구원, 방사성추적자 이용기술 개발에 관한 연구, 2002;140-176
  11. Kim JS, Kim JB, Jung SH, The RTD measurement of two stage anaerobic digester using radiotracer in WWTP, Int. conference on application of radiotracers in chemical, environmental and biological sciences, India, Mumbai, 2005;2:144-145