Phase 2 BNR/Tertiary Treatment Project
City of Modesto

Aerial of Modesto Phase 2 BNR projectAerial of Modesto Phase 2 BNR Tanks

West Yost provided full construction management services for the City of Modesto’s $100 million Phase 2 Biological Nutrient Removal/Tertiary Treatment Project. The Phase 2 work included construction of a new advanced secondary treatment and tertiary treatment facility adjacent to the existing secondary plant, and where the City’s solid waste department stored their green waste stockpiles after the final screening process. This 12.6 MGD advanced treatment system employed biological nutrient removal (BNR) followed by membrane bioreactor (MBR) technology, and UV disinfection.  The project included numerous supporting facilities including a new Operations Building, Main Electrical Building, Maintenance Shop, UV Building, BNR Blower Building, MBR Blower Building, chemical storage and pumping system, RAS pump station, WAS pump station, and the Primary Effluent and Tertiary Pump Stations. In addition, the project included two miles of 36-inch tertiary effluent pipeline from the plant to the San Joaquin River. Prior to constructing the new facilities, the City’s existing green waste composting facility had to be relocated which included a new composting windrow area, maintenance shop, operations building, and a new grinder processing pad. The entire project won a 2016 CMAA project of the year award mainly because the project was completed on-time, there were no lost-time safety incidents, and change orders were less than 1.5%.

A key element to the successful construction of the project was West Yost’s development of a 3D model of the new facilities. The 3D model proved to be a valuable tool for the CM, contractor and the operations staff for identifying conflicts, pre-planning work, and creating a 3D as-built layout of the buried utilities.