Client: Altoona Water Authority, Blair County, PA
Project Cost: $30,000,000
Gwin, Dobson & Foreman designed one of the state’s largest and most complex BNR wastewater projects for the Altoona Water Authority. This $30 million project employs a unique step-feed process for treatment of wet weather CSO flows while preserving nutrient bio-mass. The Westerly wastewater treatment plant was designed under the following criteria:
Upgrade and Expansion
Capacity: 10.8 MGD (ADF); 16.8 MGD (Max. Month); 45.8 MGD (Peak)
Annual Average Concentrations – 5.0 mg/l (TN) and 0.67 mg/l (TP)
Treatment Goals
Achieve Annual Mass Loading Limit for Nitrogen and Phosphorus
Treat Wet Weather CSO Flow
Hydraulic Expansion for Increased Capacity
Unit Operations and Process Systems
- 1. Headworks – Fine Screening and Vortex Grit Separation
- 2. Suspended Growth Nutrient Removal Technology
- 3. BNR Process Configured for Virginia Initiative Process (VIP), Stage 4/5-Bardenpho and other options
- 4. Aeration Blowers (Turbo-type)
- 5. Fine Bubble Membrane Diffuser (Oxic) and Submersible Mixers (Anoxic)
- 6. Internal Nitrate and MLSS Recycle
- 7. Step Feed Capability for Wet Weather Flows from Upstream CSO System
- 8. Final Clarification with RAS Returns
- 9. Ultraviolet Disinfection with Screw Lift Flood Pumps (Westerly Plant only)
- 10. Solids Handling – Aerobic Digestion, Belt Thickener, Centrifuge Dewatering, Biosolids Storage
The plant generated over $200,000 of nutrient-credit revenue and a $100,000 reduction in operating costs in its first year of operation. The project was endorsed by the president of the Water Environment Federation and the state regulatory agency has praised the unique and cost effective design.
The American Academy of Environmental Engineers and Scientists conferred its 2013 Superior Achievement award, which is one of the nation’s most prestigious environmental awards, to GD&F for the design of the Westerly project.