PHASE 2 BNR/TERTIARY TREATMENT PROJECT

CITY OF MODESTO

PHASE 2 BNR/TERTIARY TREATMENT PROJECT

CITY OF MODESTO

As part of a Joint Venture Design-Bid-Build partnership, Filanc served as a General Contractor for the construction of the City of Modesto Phase 2 BNR/Tertiary Wastewater Treatment Plant. The City owns and operates two wastewater treatment facilities. The facility at Sutter Avenue provides primary treatment to remove solids. Flow from the Sutter Avenue Plant travels about six miles, through two pipelines, to the treatment facility at Jennings Road. This plant, the Phase 2 BNR/Tertiary Wastewater Treatment Plant, produces 12.9 million gallons per day (MGD) of highly treated recycled water that is pumped via pipeline to the Delta-Mendota Canal to provide new water for agricultural customers in the Del Puerto Water District, as part of the North Valley Regional Recycled Water Program. This project is the City’s largest capital project to date, one of the largest installations of membranes in North America for BNR Treatment and the first application of this size for a wastewater treatment plant.

The project included construction of a primary effluent pump station and electrical building, RAS pump station, WAS and foam pump stations, tertiary effluent pump station, and consisted of two miles of effluent discharge pipeline. Work also included rotary drum fine screen facility, distribution box structure, odor control system, aeration basins, aeration blower building, mixed liquor screens, membrane bioreactor (MBR) tanks, membrane blower building, ultraviolet disinfection (UV) building, UV disinfection equipment, main electrical building, standby generators, operations center building, tertiary maintenance shop, yard structures, yard piping, electrical, site work, roads, compost facility relocation, instrumentation, control, and SCADA system. Work also included a 5,800-square-foot operations center building and the installation of the new compost facilities. Treated effluent from the Phase 2 BNR/ Tertiary facility will meet all NPDES requirements for discharging to the San Joaquin River.

In addition, Filanc completed the installation of over two miles of 36-inch diameter C200 steel pipe connecting the plant to the City’s San Joaquin River discharge pump station. To facilitate construction, we implemented an innovative cement and native soil mixing technique that helped control groundwater and also provided cathodic protection. In addition, a portion of the pipeline required jack-andbore construction to extend beneath an existing 54-inch pipeline.

Facility Features

Primary Effluent Pump Station (PEPS): The PEPS diverts 12.6 million gallons per day (MGD) of primary-treated effluent from the Sutter plant and sends it to the Phase 2 BNR/Tertiary facilities.
Fine Screens: The fine screens remove debris in the primary effluent over 1 millimeter in size. This protects the membranes and downstream treatment process.
Aeration Basins: The aeration basins are where the biological treatment process takes place. It removes biological oxygen demand (BOD), ammonia, and nitrogen from the waste stream.
Aeration Blower Building: The aeration blower building provides air to the aeration basins to support the biological nutrient removal process.
Mixed Liquor Fine Screens: Mixed liquor is the biomass that provides BNR treatment. The fine screens protect the membrane from particles larger than three millimeters that may fall into the aeration basins.
Membrane Biological Reactor (MBR) Tanks: The MBR tanks separate the biological mass from the clean water. This is done by drawing a portion of the mixed liquor through a fine membrane. There are over 16 million individual membrane fibers in the membrane tanks.
MBR Blower Building: The membrane blower system supplies air to scour the membrane and prevent solids from accumulating on the surface.
Permeate Pumps: The permeate pumps apply suction to draw clean water (permeate) through the membranes and pump it to the ultraviolet light disinfection (UV) system.
RAS Pumps: The RAS pumps pump the RAS after it has passed through the membrane tanks. The “bugs” (beneficial bacteria that treat the wastewater) are pumped back to the front of the plant to treat the next batch of wastewater coming in.
UV Disinfection System: This is the last process in the plant that disinfects the final effluent.
Tertiary Effluent Pumps: The tertiary effluent pumps pump final effluent to the Delta Mendota Canal and recycled water customers.