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The results presented in this work clearly show differences in floc growth, breakage, and recoverability for a number of different coagulants and starting suspensions

Breakage, regrowth, and fractal nature of natural organic matter flocs.

ENVIRONMENTAL SCIENCE & TECHNOLOGY, no. 7 (2005): 2307-2314

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摘要

The growth, breakage, regrowth, and fractal nature of flocs was investigated by use of a laser diffraction particle sizing device. A range of coagulants were investigated for the coagulation of natural organic matter (NOM) and compared to other coagulated systems. The results showed NOM floc structural characteristics varied in steady-sta...更多

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简介
  • Coagulation and flocculation remains the most common process used for the removal of turbidity particles and natural organic matter (NOM) at water treatment works (WTW).
  • While the major removal mechanisms of these pollutants during coagulation and flocculation have been well studied, little thought is generally given to the fundamental floc operational parameters.
  • These include physical properties such as floc size, compaction, and strength.
  • The relative breakage and regrowth of different flocculated systems have previously been compared by use of floc strength and recovery factors [2,3,4] which may be calculated as follows:
重点内容
  • Coagulation and flocculation remains the most common process used for the removal of turbidity particles and natural organic matter (NOM) at water treatment works (WTW)
  • Unit processes at WTW are generally designed to minimize floc breakage; often in practice this is not the case, with regions of high shear being prevalent [1]
  • The results presented in this work clearly show differences in floc growth, breakage, and recoverability for a number of different coagulants and starting suspensions
  • Increased floc size after the suspension has reached a plateau at the end of the initial slow stir phase is one interpretation of increased floc strength [4]
  • There was no significant difference in the fractal value of Fe-NOM flocs and Fe precipitate flocs
  • The strength of the NOM flocs is in the order polyDADMAC > ferric sulfate . alum
结果
  • There was very close agreement between experimental repeats with floc size values varying by less than 5%.
  • There was no significant difference in the fractal value of Fe-NOM flocs and Fe precipitate flocs
结论
  • The results presented in this work clearly show differences in floc growth, breakage, and recoverability for a number of different coagulants and starting suspensions.
  • For hydrolyzing coagulants such as ferric sulfate and alum, a combination of charge neutralization and entrapment/adsorption of NOM onto metal precipitates are the major floc formation routes [19]
  • These flocs are considered weak and fragile [20], probably as a result of the lack of bridging bonds holding these flocs together.
  • This may in part explain why alum and ferric NOM flocs formed smaller initial flocs
表格
  • Table1: Strength and Recovery Factors of Different-Sized NOM Flocs Formed from Three Different Coagulants after Short and Long Breakage Periodsa strength factor long
  • Table2: Strength and Recovery Factors of Flocs Formed from Different Initial Suspensions after Short and Long Breakage Periodsa strength factor long
Download tables as Excel
基金
  • This paper has been made possible through funding from American Water Works Association Research Foundation and Co-funding Utilities
引用论文
  • (1) McCurdy, K.; Carlson, K.; Gregory, D. Floc morphology and cyclic shearing recovery: comparison of alum and polyaluminum chloride coagulants. Water Res. 2004, 38, 486-494.
    Google ScholarLocate open access versionFindings
  • (2) Francois, R. J. Strength of aluminum hydroxide flocs. Water Res. 1987, 21, 1023-1030.
    Google ScholarFindings
  • (3) Fitzpatrick, C. S. B.; Fradin, E; Gregory, J. Temperature effects on flocculation using different coagulants; Proceedings of the Nano and Micro Particles in Water and Wastewater Treatment Conference; International Water Association: Zurich, Switzerland, 2003.
    Google ScholarLocate open access versionFindings
  • (4) Yukselen, M. A.; Gregory, J. The reversibility of floc breakage. Int. J. Miner. Process. 2004, 73 (2-4), 251-259.
    Google ScholarLocate open access versionFindings
  • (5) Spicer, P. T.; Pratsinis, S. E.; Raper, J.; Amal, R.; Bushell, G.; Meesters, G. The reversibility of floc breakage. Powder Technol. 1998, 97, 26-34.
    Google ScholarLocate open access versionFindings
  • (6) Chaignon, V.; Lartiges, B. S.; El Samrani, A.; Mustin, C. Evolution of size distribution and transfer of mineral particles between flocs in activated sludges: an insight into floc exchange dynamics. Water Res. 2002, 36, 676-484.
    Google ScholarLocate open access versionFindings
  • (7) Gregory, J. The role of floc density in solid-liquid separation. Filtr. Separat. 1998, 35(4), 367-371.
    Google ScholarLocate open access versionFindings
  • (8) Tang, S. A model to describe the settling behavior of fractal aggregates. Colloids Surf., A 1999, 157, 185-192.
    Google ScholarLocate open access versionFindings
  • (9) Waite, T. D.; Cleaver, J. K.; Beattie, J. K. Aggregation kinetics and fractal structure of γ-alumina assemblages. J. Colloid Interface Sci. 2001, 241, 333-339.
    Google ScholarLocate open access versionFindings
  • (10) Wu, R. M.; Lee, D. J.; Waite, T. D.; Guan, J. Multilevel structure of sludge flocs. J. Colloid Interface Sci. 2002, 252, 383-392.
    Google ScholarLocate open access versionFindings
  • (11) Bushell, G. C.; Yan, Y. D.; Woodfield, D.; Raper, J.; Amal, R. On techniques for the measurement of the mass fractal dimension of aggregates. Adv. Colloid Interface Sci. 2002, 95, 1-50.
    Google ScholarLocate open access versionFindings
  • (12) Waite, T. D. Measurement and implications of floc structure in water and wastewater treatment. Colloids Surf., A 1999, 151, 27-41.
    Google ScholarLocate open access versionFindings
  • (13) Biggs, C. A.; Lant, P. A. Activated sludge flocculation: on-line determination of floc size and the effect of shear. Water Res. 2000, 34, 2542-2550.
    Google ScholarLocate open access versionFindings
  • (14) Amirtharajah A.; O’Melia, C. R. Coagulation Processes: Destabilisation, Mixing and Flocculation. In AWWA Water Quality and Treatment: a Handbook of Community Suppliers; McGrawHill: New York, 1999.
    Google ScholarFindings
  • (15) Leentvaar, J.; Rebhun, M. Strength of ferric hydroxide flocs. Water Res. 1983, 17, 895-902.
    Google ScholarLocate open access versionFindings
  • (16) Bache, D. H.; Rasool, E. R. Characteristics of alumino-humic flocs in relation to DAF performance. Water Sci. Technol. 2001, 43 (8), 203-208.
    Google ScholarLocate open access versionFindings
  • (17) Gregory, J.; Dupont, V. Properties of flocs produced by water treatment coagulants. Water Sci. Technol. 2001, 44 (10), 231236.
    Google ScholarLocate open access versionFindings
  • (18) Bratby, J. Coagulation and Flocculation; Upland Press Ltd: Croydon, U.K., 1980.
    Google ScholarFindings
  • (19) Gregor, J. E.; Nokes, C. J.; Fenton, E. Optimising natural organic matter removal from low turbidity waters by controlled pH adjustment of aluminium coagulation. Water Res. 1997, 31, 2949-2958.
    Google ScholarLocate open access versionFindings
  • (20) Bache, D. H.; Johnson, C.; McGilligan, J. F.; Rasool, E. A conceptual view of floc structure in the sweep floc domain. Water Sci. Technol. 1997, 36(4), 49-56.
    Google ScholarLocate open access versionFindings
  • (21) Boller, M.; Blaser, S. Particles under stress Water Sci. Technol. 1998, 37, 9-29.
    Google ScholarLocate open access versionFindings
  • (22) Thomas, D. N.; Judd, S. J.; Fawcett, N. Flocculation modeling: a review. Water Res. 1999, 33 (7), 1579-1592.
    Google ScholarLocate open access versionFindings
  • (23) Jarvis, P.; Jefferson, B.; Parsons, S. A. Floc structural characteristics using conventional coagulation for a high DOC, low alkalinity surface water source. Water Res. (submitted for publication).
    Google ScholarFindings
  • (24) Yan, Y.-Y.; Burns, J. L.; Jameson, G. J.; Biggs, S. The structure and strength of depletion force induced particle aggregates. Chem. Eng. J. 2000, 80, 23-30.
    Google ScholarLocate open access versionFindings
  • (25) Jarvis, P.; Jefferson, B.; Parsons. S. A. The duplicity of floc strength; Proceedings of the Nano and Micro Particles in Water and Wastewater Treatment Conference; International Water Association: Zurich, Switzerland, 2003.
    Google ScholarLocate open access versionFindings
  • (26) Kim, S. H.; Moon, B. H.; Lee, H. I. Effects of pH and dosage on pollutant removal and floc structure during coagulation. Microchem. J. 2001, 68, 197-203.
    Google ScholarLocate open access versionFindings
  • (27) Walker, H. W.; Bob, M. M. Stability of particle flocs upon addition of natural organic matter under quiescent conditions. Water Res. 2001, 35, 875-882.
    Google ScholarLocate open access versionFindings
  • (28) Tang, P.; Greenwood, J.; Raper, J. A. A model to describe the settling behavior of fractal aggregates. J. Colloid Interface Sci. 2002, 247, 210-219.
    Google ScholarLocate open access versionFindings
  • (29) Selomulya, C.; Amal, R.; Bushell, G.; Waite, T. D. Evidence of shear rate dependence on restructuring and break-up of latex aggregates. J. Colloid Interface Sci. 2001, 236, 67-77.
    Google ScholarLocate open access versionFindings
  • (30) Guan, J.; Waite, D.; Amal, R. Rapid structure characterisation of bacterial aggregates. Environ. Sci. Technol. 1998, 32, 37353742.
    Google ScholarLocate open access versionFindings
  • 2314 9 ENVIRONMENTAL SCIENCE & TECHNOLOGY / VOL. 39, NO. 7, 2005
    Google ScholarFindings
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