Skip to main content

BNR “Then” vs “Now” A Case Study - Kalispell Advanced Wastewater Treatment Plant

Buy Article:

$9.50 plus tax (Refund Policy)

Or sign up for a free trial

An advanced wastewater treatment plant was commissioned in 1992 for the City of Kalispell, which is located in northwest Montana and discharging to a sensitive Rocky Mountain watershed. The plant featured a biological nutrient removal (BNR) process and primary sludge fermentation to ensure complete biological phosphorus (Bio-P) removal. This plant was state-of-the-art BNR at the time and has performed exceptionally well since its commissioning having been awarded many federal, state, and local awards for its excellent effluent quality. Recent rapid growth within the community however has caused plant loading to near original design loading limits and consequently initiated a review of the facility. Stantec, the original designers of the BNR processes, were retained once again to review the process with two objectives in mind: 1) to determine the reserve capacity of the existing BNR process (i.e. bioreactors, secondary clarifiers, and primary sludge fermenter), and 2) provide a longer-term expansion/upgrade plan for the facility in order to provide treatment through to the year 2025.

BioWin™ modelling was conducted on the existing Modified University Capetown (UCT) BNR process in order to determine any reserve capacity. Observations regarding favourable nitrifier growth rate, high bioreactor hydraulic residence time, and good sludge settleability and control, were considered in the analysis, and suggest the existing facility may treat an additional 35% BOD load in comparison to the original design loading. With just a fine-bubble retrofit, modelling suggests the existing process can extend treatment through to 2006 – 2007 before expansion of some sort would be required.

Beyond 2007 plant expansion is required. Stantec is recommending certain BNR upgrades be implemented in order to simplify the BNR process and reflect advances in the state of BNR technology from “then” to “now”. The primary changes recommended include converting the bioreactor configuration from a Modified UCT process to a Modified Johannesburg process, and converting from two-stage primary sludge fermentation to single-stage primary sludge fermentation.
No Reference information available - sign in for access.
No Citation information available - sign in for access.
No Supplementary Data.
No Data/Media
No Metrics

Document Type: Research Article

Publication date: 2003-01-01

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