Peters Township Sanitary Authority
spacer spacer spacer spacer

Additional Resources

Project Description (html)



Brush Run WPCP Wet Weather Improvements


The Sanitary Authority’s Brush Run Water Pollution Control Plant (WPCP), located on Valley Brook Road just West of Route 19, was expanded in 1995 to provide capacity for continued customer growth in the Brush Run Watershed of Peters Township through 2010. Since 1995, approximately 1,100 customers have been connected to the treatment facility and it is now serving its intended population. Engineering evaluations of the remaining treatment plant capacity have concluded that the treatment plant has adequate reserve capacity to serve the expected customer growth for an additional ten to twenty years without a major expansion, provided facilities are constructed to ensure adequate treatment is provided during severe wet weather events. The facilities that will be required include a third final clarifier and minor modifications to existing tanks.  

Purpose of Project

The purpose of the project is to increase the wet weather flow process treatment capacity of the Brush Run Wastewater Treatment Plant from the existing 8.5 Million Gallons Per Day (MGD) to 12.5 MGD. The improvements are necessary for the treatment plant to properly treat existing peak wet weather flows and to provide capacity for the long-term growth and economic viability of Peters Township.

Additionally, the Sanitary Authority is working cooperatively with the Township of Upper St. Clair (USC) to assist them in addressing their wet weather sewage flows at their Brush Run Sewage Pumping Station which discharges to the ALCOSAN system. Our Brush Run Wet Weather Improvement Project will provide sufficient peak flow capacity to allow us to offer sewage treatment capacity to a portion of USC enabling them to eliminate a small, inefficient sewage pumping station and thereby reduce hydraulic loading on their larger Brush Run Sewage Pumping Station which discharges to the ALCOSAN system.


The estimated total project cost is $1.5 million. The source of funds to finance the project include: a $600,000 grant from the Commonwealth Financing Authority under the H2O PA program, $600,000, and the remaining balance will utilize capital reserves.  

Project Status

The Sanitary Authority has engaged CET Engineering Services for design services. The proposed construction schedule is a 12-month period starting in April 2011 and completing April 2012.

Project Elements

Existing Final Clarifier Modifications

The Sanitary Authority worked with expert consultants to identify the most cost-effective modification to improve the wet weather performance of the existing clarifier.  These improvements included installation of density current baffles, Crosby mid-radius baffles, perimeter weir adjustments, and anti-rotation scum baffles.  The necessary materials were procured and installed by the Sanitary Authority.  The modifications were completed in July, 2010.  The modifications are contributing to significantly improve average day performance. Stress testing during moderate rain events confirms that project performance objectives will be achieved during severe rain events after the new final clarifier construction is complete.

Anoxic Selector Technology

The project includes expansion of the use at anoxic selectors to accomplish biological identification to return alkalinity to the wastewater.  The treatment process at the Brush Run WPCP is designed to remove ammonia in the wastewater, which is toxic to fish and other stream life, by a process called “nitrification”. In this process, micro organisms oxidize the ammonia (NH3-N) to Nitrate (N03-N). In doing so, most of the alkalinity naturally present in the wastewater is consumed.  This loss of alkalinity causes the final treated effluent’s pH to drop to low levels requiring the addition of chemicals, sodium bicarbonate in order to meet the discharge requirement of a minimum of 6.0 pH (7.0 is neutral).  The anoxic selectors eliminate the need to add chemicals to maintain a near neutral pH (6.5 to 7.0). 

Other benefits of Anoxic Selectors include:

  • Reduced energy requirements (lowering power costs)
  • Lower biosolids production (lowering disposal costs)
  • Improved settle ability of the micro organism used in the treatment process
  • Removal of the nutrient Nitrogen which contributes to Nutrient impairment of streams