Phase 2 BNR/Tertiary Treatment Project Updgrade
City of Modesto, California

West Yost is providing construction management (CM) services for the City’s $100 million Phase 2 Biological Nutrient Removal/Tertiary Treatment Project. The Phase 2 work includes construction of a new advanced secondary treatment and tertiary treatment facilities within the footprint of the existing secondary plant. This 12.6 mgd advanced treatment system employs biological nutrient removal (BNR) followed by membrane bioreactor (MBR) technology, with appurtenant disinfection and screening facilities, along with a new operations building and effluent pump station. In addition, the project includes two miles of 36-inch tertiary effluent pipeline from the plant to the San Joaquin River. Prior to constructing the new facilities, an existing sludge composting facility had to be relocated. Due to the close proximity to the river and large and deep excavations, careful attention was required to the contractor’s installation of dewatering and shoring systems. The project is scheduled for completion in August 2015. Change orders to date on this project are at less than 0.6-percent. 

A key element to the successful construction of the project to date is West Yost’s development of 3D models of the new facilities at the Modesto plant. These 3D drawings are a valuable tool for the CM team, including the contractor and the operations staff for identifying conflicts, preplanning work, and addressing access and operational issues.

Key facilities being constructed include:

  • Tertiary Effluent Pump Station
  • Ultraviolet (UV) Disinfection Building
  • MBR — Membrane Blower Building
  • MBR — Membrane Tanks
  • Aeration Basins (3)
  • Distribution Box
  • Fine Screens
  • Aeration Blower Building
  • RAS Pump Station
  • Chemical Storage
  • Membrane Clean-In-Place Tank
  • Main Electrical Building
  • Tertiary Shop Building
  • Operations Center