Brief Project Description

Grantee: Fairfax County, Noman Cole Jr. Pollution Control Plant

Grant:  #440-S-09-08

Fairfax County’s Noman M. Cole Jr. Pollution Control Plant (NCPCP) has a design flow of 67.0 MGD and is capable of Biological Nutrient Removal (BNR).The existing treatment system includes equalization storage, primary clarification, step-feed activated sludge treatment with anoxic zones, secondary clarification, chemical phosphorus removal, tertiary clarification, final effluent filtration, and chlorination/dechlorination prior to discharge to Pohick Creek, a tributary of the Potomac River. Under a proposal for nutrient removal cost share, the plant is being upgraded in two phases including (1) to Enhanced Nutrient Removal (ENR) capability by the construction of activated sludge tank methanol facilities and (2) to State-of-the-Art (SOA) nitrogen removal using Moving Bed Biofilm Reactors, associated plant improvements and water reuse facilities.

The ENR phase is complete with methanol facilities providing a food source for denitrifying bacteria in the activated sludge tanks.  The project includes the following:

• Construction of a new methanol storage building with fire suppression system.
• Methanol storage tanks, pumps, piping and associated electrical and instrumentation.

The ongoing SOA project phase is designed to further reduce nitrogen under design conditions stated in the June 2006 Preliminary Engineering Report. In addition to work that will rehabilitate the existing tertiary clarifiers, the SOA project phase consists of the following components:

 Package 1

• Moving Bed Biofilm Reactors (MBBR).  
• Fine Screen Facilities.
• Activated Sludge Effluent Pump Station.
• MBBR Methanol Facility.

 Package 2

• Activated Sludge Tank Modifications.

Package 3

• Fermenters (to provide alternate carbon source).
• Monomedia Filter Rehabilitation
• Flow Retention Basin.

   Package 4

  • New Equalization Tank and Equalization Tank Pump.

   Package 5

  • Reuse Facilities (new Reuse Water Pump Station and force main from NCPCP to the COVANTA power generating facility with nutrient load reduction from consumptive use as cooling water).