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Flocculation
Flocculation
Published: 2012/04/20
Channel: MITK12Videos
The Flocculation Process
The Flocculation Process
Published: 2013/11/07
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How does flocculation / flotation work? (video)
How does flocculation / flotation work? (video)
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Flocculation
Flocculation
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Channel: American Water College
How does flocculant work?
How does flocculant work?
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Coagulation Flocculation
Coagulation Flocculation
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WSO: Coagulation, Flocculation & Sedimentation DVD Preview
WSO: Coagulation, Flocculation & Sedimentation DVD Preview
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Channel: AmericanWaterWorks
WSO Water Treatment Grade 1: Coagulation & Flocculation, Ch. 8
WSO Water Treatment Grade 1: Coagulation & Flocculation, Ch. 8
Published: 2016/06/13
Channel: AmericanWaterWorks
How to quickly make a green cloudy pool CRYSTAL CLEAR blue again by using a flocculant... FLOC!
How to quickly make a green cloudy pool CRYSTAL CLEAR blue again by using a flocculant... FLOC!
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Channel: TAnya13
Visualizing Soil Properties: Dispersion and Flocculation
Visualizing Soil Properties: Dispersion and Flocculation
Published: 2016/05/18
Channel: nmsuaces
What do you mean by controlled flocculation
What do you mean by controlled flocculation
Published: 2015/08/18
Channel: Professor Tushar
Difference between deflocculated and flocculated suspension
Difference between deflocculated and flocculated suspension
Published: 2015/11/17
Channel: Professor Tushar
Recycling power wash waste water through flocculation
Recycling power wash waste water through flocculation
Published: 2014/10/27
Channel: Kristopher Cook
Lecture 10 Coagulation and Flocculation
Lecture 10 Coagulation and Flocculation
Published: 2007/12/20
Channel: nptelhrd
08 - coagulation and flocculation
08 - coagulation and flocculation
Published: 2015/03/08
Channel: Water treatment knowledge transfer channel
Flocculation in vibratory finishing
Flocculation in vibratory finishing
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Channel: Massfin
CVE 351 - Class 13 (Coagulation and Flocculation) 11 Oct 2015
CVE 351 - Class 13 (Coagulation and Flocculation) 11 Oct 2015
Published: 2015/10/11
Channel: Isaac Wait
Flocculation Meaning
Flocculation Meaning
Published: 2015/04/18
Channel: SDictionary
Aqua Excel Coagulation Flocculation and Balloons
Aqua Excel Coagulation Flocculation and Balloons
Published: 2014/12/22
Channel: Aqua Excel
Flocculation Basin Design Example
Flocculation Basin Design Example
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Channel: David Ladner
Flocculation Test
Flocculation Test
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Channel: Carlos Ramos
How to achieve flocculation in suspension (A type of liquid dosage form)
How to achieve flocculation in suspension (A type of liquid dosage form)
Published: 2015/09/05
Channel: Professor Tushar
Precipitation and Flocculation CE 586
Precipitation and Flocculation CE 586
Published: 2015/09/01
Channel: G.U.N.T. Gerätebau GmbH
Industrial Wastewater Treatment - Flocculation
Industrial Wastewater Treatment - Flocculation
Published: 2013/12/04
Channel: Advanced Waste Services
Homeade algae bio-reactor with NaOH flocculation for oil extraction
Homeade algae bio-reactor with NaOH flocculation for oil extraction
Published: 2014/06/15
Channel: BasementBiotech
Algae flocculation by Chitosan
Algae flocculation by Chitosan
Published: 2014/11/24
Channel: prabuddha gupta
Portable Flocculation Treatment System
Portable Flocculation Treatment System
Published: 2011/01/28
Channel: WSB & Associates, Inc.
Coagulation & Flocculation
Coagulation & Flocculation
Published: 2016/08/25
Channel: BEEA BD
Coagulation and Flocculation - Step 2: Flocculation
Coagulation and Flocculation - Step 2: Flocculation
Published: 2014/08/18
Channel: Rouz Busy
Wastewater Treatment - Clay Flocculation Demo
Wastewater Treatment - Clay Flocculation Demo
Published: 2011/09/15
Channel: Joan Butler
Flocculation value / Coagulating value
Flocculation value / Coagulating value
Published: 2017/08/04
Channel: Pravendra Tomar
Soil flocculation with TERRACALCO
Soil flocculation with TERRACALCO
Published: 2016/06/21
Channel: daniel toma
Flocculation Mixer - Part 1 of 2
Flocculation Mixer - Part 1 of 2
Published: 2013/02/23
Channel: Cliff Yeo
Flocculation Animation
Flocculation Animation
Published: 2011/11/22
Channel: Jean-Philippe Letullier
Deflocculated and Flocculated Glazes
Deflocculated and Flocculated Glazes
Published: 2012/12/19
Channel: John Britt
Water Treatment Process - Flocculation
Water Treatment Process - Flocculation
Published: 2014/06/05
Channel: Attilio Chiavegatti
Seleno-X  Separation from Water -Patent - bio fuel flocculation 1 liter perfect filtration
Seleno-X Separation from Water -Patent - bio fuel flocculation 1 liter perfect filtration
Published: 2013/11/11
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Controlled Flocculation - Making the Suspensions
Controlled Flocculation - Making the Suspensions
Published: 2016/06/09
Channel: Leigham
Video Flocculation Test
Video Flocculation Test
Published: 2017/08/31
Channel: Weteq S.A.
Precipitation and Flocculation
Precipitation and Flocculation
Published: 2017/03/29
Channel: Civil Engineering RWTH Aachen University
APF Flocculation
APF Flocculation
Published: 2014/12/19
Channel: Dryden Aqua
Flocculation test 1
Flocculation test 1
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Coagulation and Flocculation
Coagulation and Flocculation
Published: 2009/12/07
Channel: Magewede
Coagulant Flocculant
Coagulant Flocculant
Published: 2013/05/17
Channel: ritewaysEnviro
Lecture 11 Coagulation and Flocculation (Contd)
Lecture 11 Coagulation and Flocculation (Contd)
Published: 2007/12/20
Channel: nptelhrd
Advantages and Disadvantages of Coagulation and Flocculation
Advantages and Disadvantages of Coagulation and Flocculation
Published: 2016/11/26
Channel: Leong Khai Kit
Orchard Diary 2/7/2014:  Yeast flocculation in the shop at 45F
Orchard Diary 2/7/2014: Yeast flocculation in the shop at 45F
Published: 2014/02/07
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Controlled Flocculation - Viscosity Enhancers
Controlled Flocculation - Viscosity Enhancers
Published: 2016/06/09
Channel: Leigham
Controlled Flocculation - Demonstration of Results
Controlled Flocculation - Demonstration of Results
Published: 2016/06/09
Channel: Leigham
Yeast Flocculation in Breweries - Morgantown Brewing Company
Yeast Flocculation in Breweries - Morgantown Brewing Company
Published: 2016/04/24
Channel: Matt W
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WIKIPEDIA ARTICLE

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IUPAC definition
Flocculation (in polymer science): When a sol is colloidally unstable (I.e., the rate of aggregation is not negligible) then the formation of aggregates is called flocculation or coagulation.[1]

Agglomeration (except in polymer science)
Coagulation (except in polymer science)
Flocculation (except in polymer science)
Process of contact and adhesion whereby dispersed molecules or particles are held together by weak physical interactions ultimately leading to phase separation by the formation of precipitates of larger than colloidal size.


Note 1: In contrast to aggregation, agglomeration is a reversible process.

Note 2: The definition proposed here is recommended for distinguishing
agglomeration from aggregation.

Note 3: Quotation from ref.[1][2]

Flocculation, in the field of chemistry, is a process wherein colloids come out of suspension in the form of floc or flake, either spontaneously or due to the addition of a clarifying agent. The action differs from precipitation in that, prior to flocculation, colloids are merely suspended in a liquid and not actually dissolved in a solution. In the flocculated system, there is no formation of a cake, since all the flocs are in the suspension.

Coagulation and flocculation are important processes in water treatment with coagulation to destabilize particles through chemical reaction between coagulant and colloids, and flocculation to transport the destabilized particles that will cause collisions with floc.

Term definition[edit]

According to the IUPAC definition, flocculation is "a process of contact and adhesion whereby the particles of a dispersion form larger-size clusters". Flocculation is synonymous with agglomeration and coagulation / coalescence.[3][4]

Basically, coagulation is a process of addition of coagulant to destabilize a stabilized charged particle. Meanwhile, flocculation is a mixing technique that promotes agglomeration and assists in the settling of particles. The most common used coagulant is alum, Al2(SO4)3•14H2O.

The chemical reaction involved:

Al2(SO4)3•14H2O → 2Al(OH)3(s) + 6H+ + 3SO42- + 8H2O

During flocculation, gentle mixing accelerates the rate of particle collision, and the destabilized particles are further aggregated and enmeshed into larger precipitates. Flocculation is affected by several parameters, including mixing speeds, mixing intensity, and mixing time. The product of the mixing intensity and mixing time is used to describe flocculation processes.

Applications[edit]

Surface chemistry[edit]

In colloid chemistry, flocculation refers to the process by which fine particulates are caused to clump together into a floc. The floc may then float to the top of the liquid (creaming), settle to the bottom of the liquid (sedimentation), or be readily filtered from the liquid. Flocculation behavior of soil colloids is closely related to freshwater quality. High dispersibility of soil colloids not only directly causes turbidity of the surrounding water but it also induces eutrophication due to the adsorption of nutritional substances in rivers and lakes.

Physical chemistry[edit]

For emulsions, flocculation describes clustering of individual dispersed droplets together, whereby the individual droplets do not lose their identity.[5] Flocculation is thus the initial step leading to further ageing of the emulsion (droplet coalescence and the ultimate separation of the phases). Flocculation is used in mineral dressing.[6]

Civil engineering/earth sciences[edit]

In civil engineering, and in the earth sciences, flocculation is a condition in which clays, polymers or other small charged particles become attached and form a fragile structure, a floc. In dispersed clay slurries, flocculation occurs after mechanical agitation ceases and the dispersed clay platelets spontaneously form flocs because of attractions between negative face charges and positive edge charges.

Biology[edit]

Flocculation is used in biotechnology applications in conjunction with microfiltration to improve the efficiency of biological feeds. The addition of synthetic flocculants to the bioreactor can increase the average particle size making microfiltration more efficient. When flocculants are not added, cakes form and accumulate causing low cell viability. Positively charged flocculants work better than negatively charged ones since the cells are generally negatively charged.[7]

Cheese industry[edit]

Flocculation is widely employed to measure the progress of curd formation in the initial stages of cheese making to determine how long the curds must set.[8][9] The reaction involving the rennet micelles are modeled by Smoluchowski kinetics.[8] During the renneting of milk the micelles can approach one another and flocculate, a process that involves hydrolysis of molecules and macropeptides.[10]

Flocculation is also used during cheese wastewater treatment. Three different coagulants are mainly used:[11]

Brewing[edit]

In the brewing industry flocculation has a different meaning. It is a very important process in fermentation during the production of beer where cells form macroscopic flocs. These flocs cause the yeast to sediment or rise to the top of a fermentation at the end of the fermentation. Subsequently, the yeast can be collected (cropped) from the top (ale fermentation) or the bottom (lager fermentation) of the fermenter in order to be reused for the next fermentation. While it appears similar to sedimentation in colloidal dispersions, the mechanisms are different.[12]

Water treatment process[edit]

Flocculation and sedimentation are widely employed in the purification of drinking water as well as in sewage treatment, storm-water treatment and treatment of industrial wastewater streams. Typical treatment processes consist of grates, coagulation, flocculation, sedimentation, granular filtration and disinfection.[13]

Jar test[edit]

The purpose of this test is to select types of coagulant (alum) and also to estimate the optimal dose needed in removing the charged particles that occurred in raw water. Jar test is an experiment to understand the processes of coagulation, flocculation and sedimentation (AWWA, 2011).

Jar test apparatus consists of six batch beakers, and equipped with a paddle mixer for each beaker. In a standard practice, jar test involving of rapid mixing, then follow by slow mixing and later with sedimentation process.

Deflocculation[edit]

Deflocculation is the exact opposite of flocculation, also sometimes known as peptisation. Usually in higher pH ranges in addition to low ionic strength of solutions and domination of monovalent metal cations the colloidal particles can be dispersed.[14] The additive that prevents the colloids from forming flocs is called a deflocculant. According to the Encyclopedic Dictionary of Polymers deflocculation is "a state or condition of a dispersion of a solid in a liquid in which each solid particle remains independent and unassociated with adjacent particles. A deflocculated suspension shows zero or very low yield value".[14]

Deflocculation can be a problem in wastewater treatment plants as it commonly causes sludge settling problems and deterioration of the effluent quality.

See also[edit]

References[edit]

  1. ^ a b "Terminology of polymers and polymerization processes in dispersed systems (IUPAC Recommendations 2011)" (PDF). Pure and Applied Chemistry. 83 (12): 2229–2259. 2011. doi:10.1351/PAC-REC-10-06-03. 
  2. ^ Richard G. Jones; Edward S. Wilks; W. Val Metanomski; Jaroslav Kahovec; Michael Hess; Robert Stepto; Tatsuki Kitayama, eds. (2009). Compendium of Polymer Terminology and Nomenclature (IUPAC Recommendations 2008) "The Purple Book" (2nd ed.). RSC Publishing. ISBN 978-0-85404-491-7. 
  3. ^ IUPAC, Compendium of Chemical Terminology, 2nd ed. (the "Gold Book") (1997). Online corrected version:  (2006–) "flocculation".
  4. ^ Hubbard, Arthur T. (2004). Encyclopedia of Surface and Colloid Science. CRC Press. p. 4230. ISBN 0-8247-0759-1. Retrieved 2007-11-13. 
  5. ^ Adamson A.W. and Gast A.P. (1997) "Physical Chemistry of Surfaces", John Wiley and Sons.
  6. ^ Investigation of laws of selective flocculation of coals with synthetic latexes / P. V. Sergeev, V. S. Biletskyy // ICCS’97. 7–12 September 1997, Essen, Germany. V. 1. pp. 503–506.
  7. ^ Han, Binbing; Akeprathumchai, S.; Wickramasinghe, S. R.; Qian, X. (2003-07-01). "Flocculation of biological cells: Experiment vs. theory". AIChE Journal. 49 (7): 1687–1701. ISSN 1547-5905. doi:10.1002/aic.690490709. 
  8. ^ a b Fox, Patrick F. (1999). Cheese Volume 1: Chemistry, Physics, and Microbiology (2nd ed.). Gaithersburg, Maryland: Aspen Publishers. pp. 144–150. ISBN 978-0-8342-1378-4. 
  9. ^ Journal of Scientific and Industrial Research. 57: 680–681. 1998.  Missing or empty |title= (help)
  10. ^ Fox, Patrick F. (2004). Cheese - Chemistry, Physics and Microbiology (3rd Edition). Elsevier. p. 72. ISBN 978-0-12-263653-0. 
  11. ^ Rivas, Javier; Prazeres, Ana R.; Carvalho, Fatima; Beltrán, Fernando (2010-07-14). "Treatment of Cheese Whey Wastewater: Combined Coagulation−Flocculation and Aerobic Biodegradation". Journal of Agricultural and Food Chemistry. 58 (13): 7871–7877. ISSN 0021-8561. PMID 20557068. doi:10.1021/jf100602j. 
  12. ^ Jin, Y-L.; Speers, R.A.. (1999). "Flocculation in Saccharomyces cerevisiae Food Res. Int.". 31.: 421–440. 
  13. ^ Beverly, Richard P (2014-04-17). "Water Treatment Process Monitoring and Evaluation". Knovel. American Water Works Association (AWWA). Retrieved October 14, 2015. 
  14. ^ a b Gooch, Dr Jan W., ed. (2007-01-01). Deflocculation. Springer New York. pp. 265–265. ISBN 978-0-387-31021-3. doi:10.1007/978-0-387-30160-0_3313. 

Further reading[edit]

  • John Gregory (2006), Particles in water: properties and processes, Taylor & Francis, ISBN 1-58716-085-4
  • John C. Crittenden, R. Rhodes Trussell, David W. Hand, Kerry J. Howe, George Tchobanoglous (2012), MWH's water treatment: principles and design, third edition, John Wiley & Sons, ISBN 978-0-470-40539-0

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