Skip to main content


Buy Article:

$9.50 plus tax (Refund Policy)

Or sign up for a free trial

The North end WWTP in Tacoma, WA, was initially designed as a standard primary plant but was converted to a chemical primary treatment plant using alum and polymer plus fly ash for precipitation of TSS and associated BOD5 in the early 80's. After extensive testing to improve the performance it was converted to just alum and polymer treatment in 1985. In 1992 the City of Tacoma entered into an agreement with State of Washington, Department of Ecology and U.S. EPA to upgrade the plant to meet the effluent requirements of 30 mg/L BOD5 and TSS and a minimum of 85% removal of these contaminants. The plant could not achieve 85% removal of BOD5 consistently. Studies of alternatives resulted in a trickling filter installed to remove soluble BOD5 and a novel flushing-recycle mode to recover a portion of the TSS produced without the need for a secondary clarifier. During a 12 month optimization period and a subsequent 24 month consent order test period, the plant demonstrated its capability to produce an effluent averaging 13 mg/L BOD5 and 5 mg/L TSS with ≥92% removal of these components. The prototype solids recovery system removed 80% of the TSS without need for a follow-on clarifier or any additional clarification area. This novel improvement proved its worth during the performance evaluation tests at operating conditions which exceeded the basis of design.
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: 2000-01-01

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 These proceedings are not peer reviewed.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