Effect of Preagitation on Freeze‐Thaw‐Conditioned Sludge Dewaterability
Publication: Journal of Cold Regions Engineering
Volume 8, Issue 4
Abstract
Sludge dewatering processes are usually preceded by sludge conditioning, which improves the sludge dewaterability. Although sludge conditioning is most commonly achieved by the addition of chemicals, freeze‐thaw conditioning can also be beneficial. The most practical way of using freeze‐thaw conditioning is to dewater the sludge on a freezing bed. When sludge is pumped from its sources to the freezing bed, it is subjected to high shear force induced by the pump and turbulent pipe flow. This shear may affect the effectiveness of freeze‐thaw conditioning. The objectives of this study are to investigate the effects of preagitation on freeze‐thaw conditioning of anaerobically digested sludge. The results indicate that preagitation has positive effects on freeze‐thaw conditioning of anaerobically digested sludge. Agitation intensity was found to correlate with sludge dewaterability, with increased agitation leading to enhanced dewaterability of freeze‐thawed sludge.
Get full access to this article
View all available purchase options and get full access to this article.
References
1.
Camp, T. R., and Stein, P. C. (1943). “Velocity gradients and internal work in fluid motion.” J. Boston Soc. Civ. Engrg., 30(4), 219–239.
2.
Chen, J.‐L. (1993). “Effect of preagitation on freeze‐thaw conditioning of anaerobically digested sludge,” MS thesis, Dept. of Civ. and Envir. Engrg., Duke University, Durham, N.C.
3.
Cisse, J., and Bolling, G. F. (1971). “A study of the trapping and rejection of insoluble particles during the freezing of water.” J.Crystal Growth, 10(1), 67–76.
4.
Corte, A. E. (1962). “Vertical migration of particles in front of a moving freezing plane.” J. Geophys. Res., 67(3), 1085.
5.
Halde, R. (1980). “Concentration of impurities by progressive freezing.” Water Res., 14(6), 575–580.
6.
Katz, W. J., and Mason, D. G. (1970). “Freezing methods used to conditioning activated sludge.” Water & Sewage Works, 117(4), 110–114.
7.
Knocke, W. R., and Wakeland, D. L. (1983). “Fundamental characteristics of water treatment plant sludges.” J. AWWA, 75(10), 516–523.
8.
Knocke, W. R., and Trahern, P. (1989). “Freeze‐thaw conditioning of chemical and biological sludges.” Water Res., 23(1), 35–42.
9.
Logsdon, G. S., and Edgerley, E. Jr. (1971). “Sludge dewatering by freezing.” J. AWWA, 63(11), 734–740.
10.
Martel, C. J. (1989). “Dewaterability of freeze‐thaw conditioned sludges.” J. WPCF, 61(2), 237–241.
11.
Uhlmann, D. R., and Chalmers, B. (1964). “Interaction between particles and a solid‐liquid interface.” J. Appl. Physics, 35(10), 2986–2993.
12.
Vesilind, P. A. (1988). “Capillary suction time as a fundamental measure of sludge dewaterability.” J. WPCF, 60(2), 215–220.
13.
Vesilind, P. A., Hung, W‐Y, and Martel, C. J. (1991). “Agitation and filterability of freeze/thawed sludge.” J. Cold Regions Engrg., ASCE, 5(2), 77–83.
14.
Vesilind, P. A., and Martel, C. J. (1989). “Freezing of water and wastewater sludges.” J. Envir. Engrg., ASCE, 116(5), 854–862.
15.
Wilhelm, J. H., and Silverblatt, C. E. (1976). “Freezing treatment of alum sludge.” J. AWWA, 60(6), 312–315.
Information & Authors
Information
Published In
Journal of Cold Regions Engineering
Volume 8 • Issue 4 • December 1994
Pages: 113 - 120
Copyright
Copyright © 1994 American Society of Civil Engineers.
History
Received: Feb 8, 1994
Published online: Dec 1, 1994
Published in print: Dec 1994
Authors
Metrics & Citations
Metrics
Citations
Download citation
If you have the appropriate software installed, you can download article citation data to the citation manager of your choice. Simply select your manager software from the list below and click Download.