Skip to main content

Metro's CaRRB Diet - Centrate Treatment Process Tackles Big Challenges in a Small Package

The full text article is not available for purchase.

The publisher only permits individual articles to be downloaded by subscribers.

or click here to sign up for a free trial


In 2004, the Metro Wastewater Reclamation District (Metro) initiated an expansion project to increase capacity, improve process performance, and ensure process stability at their 380,000 m3/day (100 mgd) north secondary complex (NSEC). All of the nitrogen-rich centrate from the solids generated in both the NSEC and south secondary complex (SSEC) is returned to the NSEC. The project was to add two new aeration basins and secondary clarifiers to the existing complex of 12 aeration basins and secondary clarifiers. As an alternative approach, Metro evaluated the concept of centrate treatment with RAS in a reaeration basin. This approach afforded several important advantages over the original configuration, including increased capacity at lower cost, reduction in required mixed liquor return pumping, and improved nitrification. The facility was constructed in 2009, and performance since startup has exceeded expectations and provided confirmation of the benefits offered by this process.

Keywords: biological nutrient removal; centrate treatment; nitrification

Document Type: Research Article


Publication date: January 1, 2010

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 These proceedings are not peer reviewed.

    WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.
  • Subscribe to this Title
  • Membership Information
  • About WEF Proceedings
  • WEFTEC Conference Information
  • Ingenta Connect is not responsible for the content or availability of external websites

Access Key

Free Content
Free content
New Content
New content
Open Access Content
Open access content
Subscribed Content
Subscribed content
Free Trial 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