Title page for ETD etd-8298-18351

Type of Document

Master's Thesis

Author

Rust, Mary Elizabeth

Author's Email Address

mrust@vt.edu

URN

etd-8298-18351

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

Advisory Committee

Advisor Name	Title
Novak, John T.	Committee Chair
Love, Nancy G.	Committee Member
Randall, Clifford W.	Committee Member

Keywords

anaerobic digestion
cations
conditioning
dewatering
polysaccharide
protein
aerobic digestion

Date of Defense

1998-08-27

Availability

restricted

Abstract

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 20° C. 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.

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