Skip to main content

Effects of Feeding Conditions on Activated Sludge Characteristics and Anaerobic Digestion

Buy Article:

$9.50 plus tax (Refund Policy)

Or sign up for a free trial

The impact of reactor configuration on activated sludge properties and its subsequent influence on anaerobic digestion has been investigated in the laboratory. Activated sludge was generated in two types of reactors that mimic plug flow reactors (PFR) and continuously fed stirred tank reactors (CSTR). Two solids retention times (SRT), 4 days and 12 days, were used to generate sludge and the feed was primary effluent from a full-scale wastewater treatment plant. Various sludge properties and effluent parameters were monitored during the study. In addition, the generated activated sludges were digested under anaerobic conditions using both batch and semicontinuous modes. The settleability, dewaterability, and effluent quality of activated sludge were slightly better for PFR systems but the difference was marginal. However, anaerobic digestion of these sludges led to substantial difference between two systems. The results from both batch and semi-continuous digestions showed that sludge generated from a PFR system digests much better than a CSTR system under otherwise identical conditions. Moreover, old sludge (12 day SRT) from a PFR system showed better volatile solids reduction efficiency compared to young sludge (4 day SRT) from a CSTR system. Currently, a reactor configuration does not play a role in determining sludge digestibility. This study, however, indicated that a reactor configuration and the resultant feeding pattern have substantial influence on the digestibility of sludge under anaerobic conditions. Extraction and protein analysis by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) displayed different protein profiles between two activated sludge systems. Furthermore, there was similarity and difference for bacterial community between PFR and CSTR systems. These results suggest that different reactor configurations provide microenvironments that resulted in development of different microflora at both diversity and phenotype levels and it is these changes that influence sludge digestibility under anaerobic conditions. A more detailed study should be followed up to verify a critical role the activated sludge reactor plays in generating sludge more amenable to anaerobic digestion.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
No Metrics

Keywords: Activated sludge; CSTR; PFR; anaerobic digestion; digestibility; physiology; proteins; reactor

Document Type: Research Article

Publication date: 01 January 2009

More about this publication?
  • Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed.

    A subscription to the Proceedings of the Water Environment Federation includes access to most papers presented at the annual WEF Technical Exhibition and Conference (WEFTEC) and other conferences held since 2000. Subscription access begins 12 months after the event and is valid for 12 months from month of purchase. A subscription to the Proceedings of the Water Environment Federation is included in Water Environment Federation (WEF) membership.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access. Access begins 12 months after the conference or event
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Learn about the many other WEF member benefits and join today
  • Ingenta Connect is not responsible for the content or availability of external websites
  • Access Key
  • Free content
  • Partial Free content
  • New content
  • Open access content
  • Partial Open access content
  • Subscribed content
  • Partial Subscribed content
  • Free trial content
Cookie Policy
Cookie Policy
Ingenta Connect website makes use of cookies so as to keep track of data that you have filled in. I am Happy with this Find out more