Title page for ETD etd-8998-12279

Type of Document Master's Thesis
Author Phillips, Gary Pelham
Author's Email Address gphillip@vt.edu
URN etd-8998-12279
Title Effect of Solids Retention Time on Activated Sludge Properties and Effluent Quality
Degree Master of Science
Department Environmental Engineering
Advisory Committee
Advisor Name Title
Novak, John T. Committee Chair
Boardman, Gregory D. Committee Member
Randall, Clifford W. Committee Member
  • Solids retention time
  • activated sludge
  • effluent
  • COD
  • BOD
  • protein
  • polysaccharide
  • biopolymer
  • exocellular microbial product
  • settling
Date of Defense 1998-08-26
Availability restricted
The effect of solids retention time (SRT) or sludge age on activated sludge properties and effluent quality was investigated using laboratory scale reactors. It was found that an increase in SRT resulted in an increase in effluent solution polysaccharide, with the < 3,000 daltons (3K) size fraction contributing up to 68 percent of solution polysaccharides. The feed consisted of low molecular weight, readily degradable protein, suggesting that the observed increases in protein and polysaccharide were due to increased release of exocellular microbial product (EMP). The increase in solution protein and polysaccharide resulted in an increase in effluent chemical oxygen demand (COD). The increase in effluent COD was not accompanied by a similar increase in effluent biological oxygen demand (BOD), indicating that the EMPs released were resistant to biodegradation. At the highest SRT, the resistance to shear decreased and the capillary suction time (CST) increased. Following an initial increase, the sludge volume index (SVI) decreased at higher SRT.
  Filename       Size       Approximate Download Time (Hours:Minutes:Seconds) 
 28.8 Modem   56K Modem   ISDN (64 Kb)   ISDN (128 Kb)   Higher-speed Access 
[VT] thes_gpp.pdf 139.67 Kb 00:00:38 00:00:19 00:00:17 00:00:08 < 00:00:01
[VT] indicates that a file or directory is accessible from the Virginia Tech campus network only.

Browse All Available ETDs by ( Author | Department )

dla home
etds imagebase journals news ereserve special collections
virgnia tech home contact dla university libraries

If you have questions or technical problems, please Contact DLA.