Communications Project

Document Type:Master's Thesis
Name:Mary Elizabeth Rust
Title:Biopolymer and Cation Release in Aerobic and Anaerobic Digestion and the Consequent Impact on Sludge Dewatering and Conditioning Properties
Degree:Master of Science
Department:Environmental Engineering
Committee Chair: Dr. John T. Novak
Committee Members:Dr. Nancy G. Love
Dr. Clifford W. Randall
Keywords:protein, polysaccharide, dewatering, conditioning, cations, anaerobic digestion, aerobic digestion
Date of defense:August 27, 1998
Availability:Release the entire work for Virginia Tech access only.
After one year release worldwide only with written permission of the student and the advisory committee chair.


Sludge dewatering and chemical conditioning requirements were examined from the perspective of biopolymer and cation release from activated sludge flocs. Both aerobic and anaerobic digestion processes were considered from two different activated sludge sources at a temperature of 20C. Polymer demand and specific resistance to filtration increased with an increase in total soluble biopolymer concentration for all temperature ranges. In anaerobic digestion, the protein release was three times greater than the polysaccharide release. Conversely, aerobic digestion of the same sludge resulted in a greater release of polysaccharides than proteins. Polymer conditioning requirements in the anaerobic digestors were an order of magnitude higher than in the aerobic digestors; proteins were considered to be the biopolymer fraction responsible for the high polymer conditioning requirements and poor dewatering properties. Biopolymer is released to the supernatant as colloids bound by divalent cations. Peptidase and glucosidase activity were used to monitor enzymatic activity relative to biopolymer release and degradation. The reasons for the increases and decreases in hydrolase activity are unknown.

List of Attached Files

_3FFRONT.PDF appendb.pdf body.pdf

At the author's request, all materials (PDF files, images, etc.) associated with this ETD are accessible from the Virginia Tech network only.

The author grants to Virginia Tech or its agents the right to archive and display their thesis or dissertation in whole or in part in the University Libraries in all forms of media, now or hereafter known. The author retains all proprietary rights, such as patent rights. The author also retains the right to use in future works (such as articles or books) all or part of this thesis or dissertation.