Skip to main content


Buy Article:

$9.50 plus tax (Refund Policy)

Or sign up for a free trial

The City of Richland Wastewater Treatment Facility digesters have experienced Nocardia induced digester foaming problems from the time they went into operation in 1985. Because of the persistent foam, most or all of the thickened waste activated sludge (TWAS) was often notsent to the digesters but directly to the belt filter press to be dewatered separately from the digested sludge. It was observed that Nocardia foam was generated in the two complete-mix aeration basins. During a plant capacity assessment investigation, it was determined that one of the alternatives developed to increase the secondary system capacity coincided with one of the potential solutions previously identified to address digester foaming. One of the aeration basins was converted to plug flow operation with an anoxic selector and the existing turbine sparger aerators were replaced by panel-type fine pore diffusers. The upgrade included a classifying selector to provide physical foam removal from the aeration basin. The upgraded system has been in operation for over a year, and the plant has thus far reaped several benefits from the upgrade, including the ability to operate one aeration basin with adequate aeration, limited digester foaming, significant energy cost reduction, the ability to send all of the TWAS to the digesters, and consequently lower biosolids production rate and cost for disposal.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Article Media
No Metrics

Document Type: Research Article

Publication date: 2007-01-01

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 These proceedings are not peer reviewed.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
  • 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