Mechanisms for Overdosing in Sludge Conditioning
Publication: Journal of Environmental Engineering
Volume 119, Issue 1
Abstract
The mechanisms responsible for overdosing are studied using organic polymers as well as inorganic chemicals as sludge conditioners. Anaerobically stored sludges were used to minimize changes of sludge characteristics due to microbial activity within the period of experimentation. Conditioned sludge is considered as a two‐phase system consisting of a liquid phase and a solid phase. Sludge dewaterability is characterized by capillary suction time (CST) and specific resistance to filtration (SRF), and the sludge liquid phase is characterized by its viscosity. Based on the experimental results, it is concluded that: overdosing is only associated with polymer conditioning; the traditional use of CST and SRF does not explicitly account for the mechanisms causing overdosing behavior; increasing viscosity of the liquid phase, not reduced flocculation performance, is primarily responsible for overdosing as measured by CST and SRF: and CST is incapable of detecting measurable changes in sludge dewaterability within a fairly wide range around the optimal polymer dosage.
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Information & Authors
Information
Published In
Journal of Environmental Engineering
Volume 119 • Issue 1 • January 1993
Pages: 159 - 171
Copyright
Copyright © 1993 American Society of Civil Engineers.
History
Received: Nov 19, 1991
Published online: Jan 1, 1993
Published in print: Jan 1993
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