Skip to main content

Comparison of Methods to Evaluate Nitrification Kinetics: WERF “High F/M” and “Low F/M” Protocols

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


Water Environment Research Foundation (WERF) presented three methods targeted to improve the accuracy of nitrifier maximum specific growth rate (μmax) measurements: High Food to Micro-organism (F/M), Low F/M, and the Washout methods (2003). By reducing the time and effort required, these methods encourage direct measurement of μmax for each wastewater treatment facility, instead of relying on textbook values with added safety factors. Reducing the design μmax has a significant impact on cost of nitrification, in that a small percent increase in μmax can result in a significant decrease in required aeration volume, and thus a significant cost savings.

The High F/M, Low F/M, and Washout Methods utilize different experimental protocols, and each presents different advantages. This work focused on comparing results from the High and Low F/M methods at two different wastewater temperatures. In addition to steady-state comparisons, temperature shock tests were performed to investigate each method's effectiveness at estimating μmax during temperature change, to determine whether such shock tests can be used as surrogates for the time-consuming process of developing temperature-acclimated biomass. New biomass is produced during the High F/M method, but not (theoretically) during the Low F/M assay, suggesting that the two methods respond very differently to temperature shock testing. The performance of either method under laboratory conditions during temperature shock testing has yet to be demonstrated definitively.

Keywords: Maximum specific nitrifier growth rate; bench-scale testing; high F/M; low F/M; temperature shock testing

Document Type: Research Article


Publication date: January 1, 2009

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 These proceedings are not peer reviewed.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