COAGULATION TESTING: A COMPARISON OF TECHNIQUES—<i>PART 1</i>

Tekippe, Rudy J.; Ham, Robert K.

doi:10.1002/j.1551-8833.1970.tb03972.x

Cited by 22 publications

(9 citation statements)

References 22 publications

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“…l Plot the values of K, as ordinate and In G as abscissa. The value of Ks at any G value normally follows a relationship of the form K, = k, In G + k2 (5) where k, and k, are constants for a particular water. The empirical relationship between the breakup constant Ks and velocity gradient G given in Eq 4 is merely for convenience in analysis.…”

Section: Methodsmentioning

confidence: 99%

Interpreting laboratory results for the design of rapid mixing and flocculation systems

Bratby¹

1981

Journal AWWA

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Section: Methodsmentioning

confidence: 99%

Interpreting laboratory results for the design of rapid mixing and flocculation systems

Bratby¹

1981

Journal AWWA

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“…TeKippe and Ham, 106 in a comparative study of methods of coagulation testing, suggested that smaller floe particles probably have better filtration properties. This would eliminate the need for conventional flocculation prior to filtration, and make the rapid mixing process prior to direct filtration an important factor in determining filter efficiency.…”

Section: Point and Mode Of Application Of The Polymermentioning

confidence: 98%

“…More recent models utilize multiaperture operation" 4 with a pulse height analyzer (PHA) 126 and multichannel storage facility (MCA). 106 One disadvantage of the technique is the requirement for dilution of the suspension under investigation with a 1.0 M electrolyte (usually NaCl). This raises questions regarding the effect of ionic strength on particulates, especially in flocculated water.…”

Section: Electrical Resistance Measurements (Coulter Counter)mentioning

confidence: 99%

Granular media filtration in water and wastewater treatment: Part 2∗

Jackson¹,

Letterman

1980

C R C Critical Reviews in Environmental Control

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VII. POLYELECTROLYTES AS FILTER AIDSThe importance of surface chemistry to the process of granular media filtration was noted in Section V of Part I of this article. Beneficial changes in the surface chemical properties of granular media and suspended solids can be brought about by the addition of an appropriate chemical reagent (an inorganic and/or an organic coagulant/ flocculant, for example) to the wastewater stream. Although seldom taken into consideration in the models proposed to explain particle deposition and removal, chemicalaided granular media filtration is, in fact, widely practiced to improve the performance of full-scale filtration units.This section deals with the role and use of chemicals as filtration aids, with their selection, point and mode of application, and the methods used to determine the dose of chemical needed to optimize filter performance. Chemicals referred to by trade name in the text are identified according to structure in Appendix B.

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“…Black et al 1957), the jar test has remained the conventional method of understanding coagulation chemistry and optimizing flocculation mixing. A noted criticism of this ubiquitous tool relates to the reactor similitude to the true hydraulic conditions of fullscale coagulation/flocculation processes (TeKippe & Ham 1970). Although the use of traditional jar tests for flocculation control provide some indication of the appropriate type and concentration of flocculants, Argaman (1971) argued that pilot-plant studies are essential for assuring the success of the design of new plants.…”

Section: Introductionmentioning

confidence: 99%

Determination of conventional velocity gradient (G) using CFD technique for a pilot-scale flocculation system

Vadasarukkai

Gagnon

2010

Journal of Water Supply: Research and Technology-Aqua

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Achieving uniform mixing conditions are essential for the fioccuiation process to optimize floe size and avoid floc-breakup. Limited literature is available on establishing consistent operational conditions and procedures for pilot-scale fioccuiation systems, which have tank sizes smaller than full-scale and larger than jar-test equipment, in this study, the influence of mixing speeds on the determination of the conventional design parameter, the average velocity gradient (G), was investigated for pilot-scale paddle flocculators. The pilot-scale plant for this paper was hosted at the J.D. Kline water Supply Plant (JDKWSP) in Halifax, Canada. Computational fluid dynamics (CFD) was evaluated as an alternative design technique and compared against traditionally used empirical-based calculations. Comparison of both approaches showed that the G-values of empirical method were substantially higher than the predicted values for rotational speeds greater than 5 rpm. In contrast, CFD predictions found that G-values used for tapered paddle fioccuiation process (up to 60s"^) could be achieved at lower rotational speed (around 15 rpm), which minimizes the power input required for mixing. The practical implications of operating at higher than required G-values relates to potential negative consequences such as floe break up, and the reliance of chemical additives to avoid floe break-up. These very practical outcomes could impact the interpretation of findings from pilot-scale treatment systems. NOMENCLATURE Ap C CD CFD FE FTC FV FD G projected area of paddle (m^) mean tracer concentration (kgm^) drag coefficient on paddle for turbulent flow (dimensionless number) computational fluid dynamics finite element flow through curve finite volume drag force on paddles global root mean square velocity gradient or energy input rate (s~^)

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COAGULATION TESTING: A COMPARISON OF TECHNIQUES—PART 1

Cited by 22 publications

References 22 publications

Interpreting laboratory results for the design of rapid mixing and flocculation systems

Interpreting laboratory results for the design of rapid mixing and flocculation systems

Granular media filtration in water and wastewater treatment: Part 2∗

Determination of conventional velocity gradient (G) using CFD technique for a pilot-scale flocculation system

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