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.

Name thesis:degree_name

Master of Science

Level thesis:degree_level

masters

Discipline thesis:degree_discipline

Environmental Planning

Department dc:contributor.department

Environmental Engineering

Grantor dc:publisher

Virginia Tech

Year dc:date.issued

2000

Author dc:creator

• Bivins, Jason Lee

Chair dc:contributor.committeechair

• Novak, John T.

Committee members dc:contributor.committeemember

• Love, Nancy G.
• Randall, Clifford W.

• conditioning
• biopolymer
• dewatering
• digestion
• anaerobic
• mesophilic
• thermophilic

Statement dc:rights

• In Copyright

Licence dc:rights.uri

• http://rightsstatements.org/vocab/InC/1.0/

Language dc:language.iso

en

Dc Identifier Other

etd-12182000-114810

OAI identifier oai:identifier

oai:vtechworks.lib.vt.edu:10919/36254