Skip to main content

Primary Sludge Fermenters in BNR Plants: Are they Cost-Effective for Meeting Effluent Phosphorus Limits?

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


The 100 ML/d Pine Creek WWTP is a state-of-the-art BNR facility that serves the City of Calgary, Alberta. A delay in the construction of the primary sludge fermenters allowed a comparison of the performance of the BNR process with and without fermentation for extended periods of time, and facilitated a life-cycle cost analysis in which the cost of primary sludge fermentation was compared with alternative forms of primary sludge thickening and meeting the effluent total P limit by chemical addition. Data from the first 20 months of plant operation indicated that, with primary sludge fermentation, the plant is capable of reliably meeting its stringent effluent total P target of <0.3 mg/L. Without fermentation, the plant required the in-plant addition for approximately 50 mg/L of alum to meet this same effluent quality standard. The life-cycle cost comparison between primary sludge fermentation and enhanced biological phosphorus removal (EBPR), and two alternative forms of primary sludge thickening and chemical P removal, indicated that primary sludge fermentation is a cost-effective method of reliably meeting a stringent effluent total P standard. Using a 20-year net present value (NPV) analysis, xprimary sludge fermentation was found to be approximately 8 percent cheaper than mechanical primary sludge thickening and chemical P removal, and 22 percent cheaper than gravity thickening of primary sludge and chemical P removal.

Keywords: Biological nutrient removal; enhanced biological phosphorus removal (EBPR); in-plant alum addition; life-cycle cost analysis; primary sludge fermentation

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 These proceedings are not peer reviewed.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