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Characteristic Features and Effect of Neo-Hydrofoil Impeller Applied in Sewage Treatment Plants

하수처리 공법별 네오하이드로포일 교반기의 적용 특성 및 효과

Joo, Yoon-Sik;Son, Guntae;Bae, Youngjun;Lee, Seunghwan
주윤식;손건태;배영준;이승환

  • Received : 2016.02.01
  • Accepted : 2016.03.31
  • Published : 2016.04.15

Abstract

In this study, a newly developed agitator with hydrofoil impeller applied to actual biological process in advanced wastewater treatment plant was evaluated. Several series of experiments were conducted in two different wastewater treatment plants where actual problems have been occurred such as the production of scums and sludge settling. For more effective evaluation, computational fluid dynamics (CFD) and measurements of MLSS (Mixed Liquor Suspended Solids) and DO (Dissolved Oxygen) were used with other measuring equipments. After the installation of one unit of vertical hydrofoil agitator in plant A, scum and sludge settling problems were solved and more than seventy percent of operational energy was saved. In case of plant B, there were three cells of each anoxic and anaerobic tanks, and each cell had one unit of submersible horizontal agitator. After the integration of three cells to one cell in each tank, and installation of one vertical hydrofoil agitator per tank, all the problems caused by improper mixing were solved and more than eighty percent of operational energy was found to be saved. Simple change of agitator applied to biological process in wastewater treatment plant was proved to be essential to eliminate scum and sludge settling problems and to save input energy.

Keywords

CFD;DO;Energy Input;Hydrofoil Impeller;MLSS

References

  1. American Water Works Association Research Foundation (1991), "Mixing in Coagulation and Flocculation", pp.110-150.
  2. Bae. Y. G, Kim .D. H, Hwang. S. T, Moon. Y. J (2015). Three Dimensional Flow Computation And Performance Characteristics Analysis of Propellers For Water Treatment Mixer, J. Comput. Fluids Eng, 20(1), pp. 10-15. https://doi.org/10.6112/kscfe.2015.20.1.010
  3. Bridgwater. J (2012), Mixing of powders and granular materials by mechanical means-a perspective, Particuology, 10, pp. 397-427. https://doi.org/10.1016/j.partic.2012.06.002
  4. Edward L. Paul, Vicrot A. Antierno-Obeng (2004), Handbook of Industrial Mixing, Wiley-Interscience, New Jersey
  5. Ihejirika. I, Ein-Mozaffari. F (2007), Using CFD and ultrasonic velocimetry to study the mixing of pseudoplastic fluids with a helical ribbon impeller, Chem. Eng. Technol, 30, pp. 606-614. https://doi.org/10.1002/ceat.200700006
  6. Kim. D. K, Bae. S. T, Lee. C. J, Park. J. H, Kim. O. K (2006). Flow Characteristics About Industrial Agitators Impeller Shape by CFD, Proceedings of Korea Society of Marine Engineering Conference, 22 June, 2006, Busan, Korea
  7. Kim. D. K, Bae. S. T, Park. J. H (2006), Study on the Industrial Agitator's Impeller Shape Analysis Using CFD and Reverse Engineering, J. of Society of CAD/CAM Engineers, 11(5), pp. 359-346.
  8. Kim D. K, Kim. J. H (2007), "A Study about Choice of Industrial Mixer's Impeller Type for PIV and CFD", Jouranl of the Korean Society of Marine Engineering, 31(6), pp.797-803. https://doi.org/10.5916/jkosme.2007.31.6.797
  9. Kelly. W, Gigas. B (2003), Using CFD to predict the behavior of power law fluids near axial-flow impellers operating in the transition flow regime, Chem. Eng. Sci, 58, pp. 2141-2152. https://doi.org/10.1016/S0009-2509(03)00060-5
  10. Kelly. W, Humphrey. A (1998), Computational fluid dynamics model for predicting flow of viscous fluids in a large fermentor with hydrofoil flow impellers and internal cooling coils, Biotechnol. Prog, 14, pp. 248-258. https://doi.org/10.1021/bp9701168
  11. Kumaresan. T, Joshi. J (2006), Effect of impeller design on the flow pattern and mixing in stirred tanks, Chem. Eng. J, 115, pp. 173-193. https://doi.org/10.1016/j.cej.2005.10.002
  12. Noh Hyung-Un, (2007), "Select optimal agitator" Journal of Fluid Machinery, 10(3), pp. 55-66.
  13. Ottino. J.M, Khakhar. D.V (2000), Mixing and segregation of granular materials, Annu. Rev. Fluid Mech, 32, pp. 55-91. https://doi.org/10.1146/annurev.fluid.32.1.55
  14. Park. J. H (2003). The Effect of Impeller Shapes on the Flow Field of the Mixing Tank, Master's Thesis, Youngnam University, Daegu, Korea, pp. 9-13
  15. Zalc. J.M, Szalai. E.S, Alvarez. M.M, Muzzio. F.J (2002), Using CFD to understand chaotic mixing in laminar stirred tanks, AIChE J. 48, pp. 2124-2134. https://doi.org/10.1002/aic.690481004
  16. Zienkiewicz. O. C (1977), "The Finite Element Method, 3rd ed, McGraw-Hill, London, pp.52-80.