Investigating the Fundamental Basis for Selectors to Improve Activated Sludge Settling
Aerobic, anoxic, and anaerobic selectors have become popular for controlling filamentous bulking in activated sludge systems; however, selectors are not always successful. Regression analyses of data collected from 44 full-scale wastewater treatment plants, with operating selectors, provided criteria for determining when selectors will and will not be successful. Anoxic selectors do not appear to control filamentous bulking in long-mean cell residence time (MCRT) plants. Further, the elimination of all anoxic zones may help to control bulking in these plants. Other design/operating parameters, however, were shown to influence activated sludge settleability in long-MCRT plants. Aerobic selectors in short-MCRT plants do control filamentous bulking if they are small enough to produce a biochemical oxygen demand (BOD) concentration gradient in the aeration basins. Anoxic and anaerobic selectors do control filamentous bulking in short-MCRT plants if the selector volume is large enough and/or the selector mixed liquor suspended solids concentration is high enough. These selector systems do not appear to benefit from a BOD concentration gradient as the aerobic selectors in short-MCRT plants do. Although anaerobic/anoxic selector compartmentalization in these plants appears to improve settleability, this is presumably because of reduced selector short-circuiting.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
Document Type: Research Article
Publication date: 2006-01-01
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 These proceedings are not peer reviewed.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