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Changes in Dewatering Properties Between the Thermophilic and Mesophilic Stages in TPAD Systems

Temperature-phased anaerobic digestion (TPAD) has become increasingly appealing in recent years due to the pathogen destruction capabilities of the system. However, there has also been concern about the dewatering properties of the sludges created by these systems. A laboratory study was conducted at Virginia Tech to determine the effect of thermophilic solids retention time (SRT) on sludge dewatering properties, to characterize system parameters associated with dewatering, and to understand the mechanisms causing changes in dewatering properties between the thermophilic and mesophilic phases. The study showed that while anaerobic digestion caused dewatering properties to deteriorate, sludges varied little with thermophilic SRT. Acidogenesis was essentially complete after 1.5 days. Subsequent mesophilic digestion resulted in little change to dewatering properties and modest reductions in conditioning doses, but substantial reductions in biopolymer (protein + polysaccharides) occurred. It appears that thermophilic anaerobic digestion creates or releases colloidal materials that cause dewatering to be poor and subsequent mesophilic digestion for 15 days does little to improve sludge properties of TPAD systems. / Master of Science

Identiferoai:union.ndltd.org:VTETD/oai:vtechworks.lib.vt.edu:10919/36254
Date18 December 2000
CreatorsBivins, Jason Lee
ContributorsEnvironmental Engineering, Novak, John T., Love, Nancy G., Randall, Clifford W.
PublisherVirginia Tech
Source SetsVirginia Tech Theses and Dissertation
LanguageEnglish
Detected LanguageEnglish
TypeThesis
Formatapplication/pdf
RightsIn Copyright, http://rightsstatements.org/vocab/InC/1.0/
RelationThesis(PDF).pdf

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