Environmental Engineering Research

Korean Society of Environmental Engineers (대한환경공학회)
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Effects of hydrodynamics and coagulant doses on particle aggregation during a rapid mixing

  • Park, Sang-Min (Environmental Infrastructure Research Department, National Institute of Environmental Research(NIER)) ;
  • Heo, Tae-Young (Department of Information Statistics, Chungbuk National University) ;
  • Park, Jun-Gyu (Department of Environmental Engineering, Chungbuk National University) ;
  • Jun, Hang-Bae (Department of Environmental Engineering, Chungbuk National University)
  • Received : 2016.03.16
  • Accepted : 2016.06.30
  • Published : 2016.12.30
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Abstract

The effects of hydrodynamics and alum dose on particle growth were investigated by monitoring particle counts in a rapid mixing process. Experiments were performed to measure the particle growth and breakup under various conditions. The rapid mixing scheme consisted of the following operating parameters: Velocity gradient (G) ($200-300s^{-1}$), alum dose (10-50 mg/L) and mixing time (30-180 s). The Poisson regression model was applied to assess the effects of the doses and velocity gradient with mixing time. The mechanism for the growth and breakup of particles was elucidated. An increase in alum dose was found to accelerate the particle count reduction. The particle count at a G value of $200s^{-1}$ decreased more rapidly than those at $300s^{-1}$. The growth and breakup of larger particles were more clearly observed at higher alum doses. Variations of particles due to aggregation and breakup of micro-flocs in rapid mixing step were interactively affected by G, mixing time and alum dose. Micro-flocculation played an important role in a rapid mixing process.

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References

  1. Sampath M, Shukla A, Rathore AS. Modeling of filtration processes-Microfiltration and depth filtration for harvest of a therapeutic protein expressed in pichia pastoris at constant pressure. Bioengineering 2014;1:260-277. https://doi.org/10.3390/bioengineering1040260
  2. Matsushita T, Matsui Y, Shirasaki N, Kato Y. Effect of membrane pore size, coagulation time, and coagulant dose on virus removal by a coagulation-ceramic microfiltration hybrid system. Desalination 2005;178:21-26. https://doi.org/10.1016/j.desal.2004.11.026
  3. Hudson H, Wolfner JP. Design of mixing tank and flocculation basins. J. Am. Water Works Assoc. 1976;59:1257.
  4. Vrale L, Jarden RM. Rapid mixing in water treatment. J. Am. Water Works Assoc. 1971;63:52-58. https://doi.org/10.1002/j.1551-8833.1971.tb04027.x
  5. Kawamura S. Consideration in improving flocculation. J. Am. Water Works Assoc. 1976;68:328-336. https://doi.org/10.1002/j.1551-8833.1976.tb02421.x
  6. Amirtharajah A, Mills KM. Rapid mix design for mechanisms of alum coagulation. J. Am. Water Works Assoc. 1982;74: 210-216. https://doi.org/10.1002/j.1551-8833.1982.tb04890.x
  7. Camp TR. Floc volume concentration. J. Am. Water Works Assoc. 1968;60:656-673. https://doi.org/10.1002/j.1551-8833.1968.tb03592.x
  8. Letterman RD, Quon JK, Gemmel RC. Influence of rapid mix parameters on flocculation. J. Am. Water Works Assoc. 1973;65:716-725. https://doi.org/10.1002/j.1551-8833.1973.tb01933.x
  9. Lai RJ, Hudson HE, Singley JE. Velocity gradient calibration of jar-test equipment. J. Am. Water Works Assoc. 1975;67: 553-557. https://doi.org/10.1002/j.1551-8833.1975.tb02294.x
  10. Mhaisalkar VA, Paramasivam R, Bhloe AG. Optimizing physical parameters of rapid mix design for coagulation-flocculation of turbid waters. Water Res. 1991;25:43-52. https://doi.org/10.1016/0043-1354(91)90097-A
  11. Rossini M, Garcia Garrido J, Galluzzo M. Optimization of the coagulation-flocculation treatment: Influence of rapid mix parameters. Water Res. 1999;33:1817-1826. https://doi.org/10.1016/S0043-1354(98)00367-4
  12. Park SM, Jun HB, Jung MS, Koo HM. Effects of velocity gradient and mixing time on particle growth in a rapid mixing tank. Water Sci. Technol. 2006;53:95-102.
  13. McCullagh P, Nelder JA. Generalized linear models. 2nd ed. New York: Chapman and Hall; 1989.
  14. Liley JB. Fitting size distributions to optical particle counter data. Aerosol Sci. Technol. 1992;17:84-92. https://doi.org/10.1080/02786829208959562
  15. Christian S, Mathias H, Bastian W, Arben J, Matthias B. Experimental study of electrostatically colloidal particles: Colloidal stability and charge reversal. J. Colloid Interf. Sci. 2011;358:62-67. https://doi.org/10.1016/j.jcis.2011.02.039
  16. Lopez-Garcia JJ, Arandra-Rascon MJ, Grosse C, Horno J. Electrokinetics of charged colloidal particles taking into account the effect on ion size constraints. J. Colloid Interf. Sci. 2011;356:325-330. https://doi.org/10.1016/j.jcis.2010.12.063
  17. Ranran M, Yan W, Bo Z, Weiying X, Min D, Baoyu G. Impact of enhanced coagulation ways on flocs properties and membrane fouling: Increasing dosage and applying new composite coagulant. Desalination 2013;314:161-168. https://doi.org/10.1016/j.desal.2013.01.012