Seneca Wastewater Treatment Plant


The Seneca Wastewater Treatment Plant project consisted of the new construction and upgrades to the 25-year-old facility. Modernization of the existing facility was necessary to meet future wastewater needs of upper Montgomery County residents. Using advanced technology to protect the environment and the Chesapeake Bay, the Washington Suburban Sanitary Commission (WSSC) expanded the average plant capacity from 5-mgd to 20-mgd, with the possibility of future expansion capacity of 26-mgd. The new wastewater treatment plant uses state-of-the-art biological and chemical processes that remove 64-percent more nitrogen along with 77-percent more phosphorous than the original 5-mgd plant.


Specialized Engineering was responsible for monitoring Construction Quality Assurance/Quality Control (QA/QC) during the phases of construction.

Testing and Inspection Services provided by Specialized Engineering included the following:

  • Structural Backfill/Fill
  • Reinforcing Steel
  • Structural Steel
  • Formwork
  • Concrete Pre-Placement
  • Cast-In-Place Concrete

Specialized Engineering conducted laboratory testing and analysis of proposed fill materials, testing of concrete cylinders, and soil samples. Wish to learn more about our involvement with this project? Please contact us at 800-773-3808.