The Additional Digester Facility Upgrades (ADFU) project focuses on the renewal of the San José-Santa Clara Regional Wastewater Facility (RWF) mesophilic digesters.

The RWF has 12 anaerobic digesters. Four (4) of the 12 have recently been upgraded from mesophilic to thermophilic to create a temperature-phased anaerobic digestion (TPAD) process. The remaining 8 digesters, range from 50 to 60 years old. Many of the parts in these digesters are out of date or reaching the end of their lifespans.

The ADFU project will renew the tanks’ structure and implement upgrades to several components, including:

• Mechanical upgrades to six digesters:
  • Renewed structures
  • New, fixed covers replacing floating covers
  • New mixing systems
• New electrical and instrumentation and control equipment
• Replacement of Digester 9-16 Digester Overflow System to prepare for rapid rise events

The project is being delivered using the design-build project delivery model.

• Current Stage: Project Definition & Criteria Docs 
• Owner’s Advisor: Carollo 
• Design-Builder: Not Assigned 
• Adopted Budget: $130.2 million 
• Expected Beneficial Use: December 2030

(Image caption: One of the anaerobic digesters slated for upgrades.)

Rehabilitate portions of the aging RWF secondary treatment facilities that consist of BNR1, BNR 2, secondary clarifiers, nitrification clarifiers, and associated RAS/WAS facilities. Implement a nitrogen removal process in the BNR 2B battery to meet new RWF permit limits for total inorganic nitrogen. Upgrades may include a new carbon feed and storage facility. The project is being delivered using the design-build project delivery model.

Rectangular Aeration Basins at BNR2 will be modified to meet new Total Inorganic Nitrogen limits, and circular clarifiers will be rehabilitated with new mechanisms.

• Current Stage: Project Definition & Criteria Docs 
• Consultant: Unassigned
• Contractor: Unassigned
• Construction Budget: $240 Million
• Expected Beneficial Use: October 2033

Filtered air will be provided to the Blower VFD Room to protect from dust build-up.

This project’s scope is the design and construction of a new closed-loop HVAC system for the variable-frequency drive (VFD) room in Building 40. This system will be similar to other VFD rooms in the RWF and will consist of an air-handling unit as well as supply & return ductwork. This project is being delivered using a Design-Bid-Build Fast-Track model.

• Current Stage: Detailed Design;
• Consultant: Brown & Caldwell;
• Contractor: Unassigned
• Adopted Budget: $4.6 million;
• Expected Beneficial Use: August 2027

Current security infrastructure, to be replaced with a new and improved security system. 

Much of the RWF’s security infrastructure is out of date and failing. Maintaining the RWF as a safe and secure facility is a priority. This project will upgrade and install various security features throughout the site, including:

• Access card readers in public buildings, server rooms, chemical supply rooms, warehouse doors, and other buildings.
• New card readers at remote gates, the entrance to outfall channel, and other perimeter gates. 
• Two new proximity card badging stations. 
• Closed-circuit televisions utilizing both wired and wireless cameras in various locations.
• Associated server room upgrades including HVAC, electrical, fiber, racks, etc. 

This project is being delivered using a Design-Bid-Build Fast-Track model. 

• Current Stage: Bid and Award
• Consultant: Jacobs
• Contractor: Unassigned 
• Adopted Budget: $13.7 million      
• Expected Beneficial Use: December 2027

The RWF currently dries (dewaters) biosolids in open-air drying beds before they are disposed of in a landfill. The 2013 Plant Master Plan recommended transitioning from the open-air drying beds and lagoons to an enclosed mechanical dewatering process.    
This transition would allow the RWF to: 

Produce a product with a variety of beneficial reuse options.
• Reduce odors in the community.
• Free up 750 acres of RWF land for alternative uses.

The project will build a new mechanical dewatering facility and associated support facilities. The project is delivered using a Design-Build model.

(Image caption: Aerial view of the new Dewatering Building under construction.)

• Current Stage: Final Design and Construction
• Owner’s Advisor: Brown and Caldwell
• Design-Builder: Walsh Construction
• Adopted Budget: $176.7 million
• Expected Beneficial Use: September 2026

The RWF has four water systems: potable water, groundwater, process water, and fire protection water. Many components of the water systems are now beyond their useful life and require frequent repairs due to leaks and failures. Additionally, changes to RWF water uses and demands require modifications to the existing systems.

This project will:

• Replace deteriorated pipes for potable water, ground water and process water systems.
• Combine the groundwater and process water systems to use only process water and discontinue groundwater use.
• Convert the fire protection water system supply from final plant effluent to potable water.
• Add connections to existing support buildings and new facilities.
• Install appurtenances such as water storage tanks, new pump stations, and high-pressure loops.

This project is being delivered using a Design-Bid-Build model.

• Current Stage: Construction & Commissioning 
• Consultant: Kennedy/Jenks Consultants Inc.
• Contractor: Ranger Pipelines Inc.
• Adopted Budget: $69 million
• Expected Beneficial Use: June 2027

(Image caption: A construction shot of an aging pipe approaching the end of its lifespan being excavated.) 

The filtration process is one of the final steps in wastewater treatment. The RWF’s tertiary filtration unit process consists of 16 granular media filters and ancillary equipment. Built in the 1970s and 1980s, these components are near the end of their useful lives. Structural, mechanical, electrical, and instrumentation/control elements of the system need rehabilitation.

These improvements will ensure that the RWF continues to produce effluent quality in compliance with the RWF’s discharge permit, and recycled water in compliance with Title 22 requirements.

The main project components are:

• Replacement of all valves and actuators in the filter gallery.
• Replacement of the granular filter media.
• Replacement of the existing surface wash system with a new air scour system.
• Rehabilitation of three electrical switchgears, including related motor control consoles.
• Repairs to concrete cracks.

This project is being delivered using a Design-Bid-Build model.

• Current Stage: Construction and Commissioning
• Consultant: Kennedy/Jenks Consultants Inc.
• Contractor: Walsh Construction Company, LLC
• Adopted Budget: $60 million
• Expected Beneficial Use: March 2025

The RWF's main operational area is approximately 150 acres and houses unit treatment processes and more than two dozen support building facilities. The support buildings are now between 30 and 60 years old.

In late 2011, a Fire Code Compliance Gap Analysis study identified fire code compliance gaps and fire risk potentials in most of the support buildings. Since 2012, RWF staff have implemented standard operating procedures and taken corrective actions to address many of the findings, but some findings remain outstanding and need capital construction.

This project will address the remaining findings in the support buildings to include:

• Installing new fire alarm systems.
• Modifying existing fire alarm systems.
• Removing abandoned fire alarm systems.
• Providing a new centralized fire alarm monitoring system.

This project is being delivered using a Design-Bid-Build model.

• Current Stage: Construction and Commissioning
• Consultant: Kennedy/Jenks Consultants Inc.
• Contractor: Blocka Construction
• Adopted Budget: $7.8 million
• Expected Beneficial Use: December 2024

Most of the RWF HVAC equipment are original to the buildings built thirty to fifty years ago and function at a minimum level of reliability. The existing equipment is not energy efficient, and parts are no longer available to repair aging units. Additionally, as portions of the older buildings have been decommissioned, there are advantages to replacing the existing HVAC equipment with new energy efficient units to serve the repurposed spaces.

These improvements will be delivered in two phases and includes installation of:

• New HVAC systems in 15 buildings.
• A chiller system and cooling tower.
• Natural gas seismic shut-off valves in 7 buildings.
• A complete Building Management System (BMS) with monitoring station.
• Electrical work and ancillary equipment.

This project is being delivered using a Design-Bid-Build model.

Phase 1:

• Current Stage: Detailed Design
• Consultant: Unassigned
• Contractor: Unassigned
• Adopted Budget: $13.7 million
• Expected Beneficial Use: August 2028

Phase 2:

• Current Stage: Preliminary Design (30%)  
• Consultant: CDM Smith 
• Contractor: Unassigned
• Adopted Budget: $32 million
• Expected Beneficial Use: June 2029

(Image caption: Workers conducting a safety inspection of HVAC components.)

The New Headworks Access Road project will design and build an access roadway to Headworks 3. The project’s scope also includes a drainage study to gain insight on the most efficient way to drain both the new access roadway and undesired ponding in construction-enabling areas.

This project is being delivered using a Design-Bid-Build Fast Track model.

• Current Stage: Construction and Commissioning
• Consultant: Brown & Caldwell
• Contractor: O.C. Jones & Sons
• Adopted Budget: $5.2 million
• Expected Beneficial Use: April 2025

The RWF discharges treated wastewater into the San Francisco Bay. This discharge is regulated by the National Pollutant Discharge Elimination System (NPDES) permit and compliance with permit conditions depend on highly sensitive instrument that record and gather data on water quality. Some equipment are located at the weir structure and in the nearby S02 building at the end of the outfall channel. Also, where the channel begins, flow meters inside two huge pipelines constantly measure treated effluent flow rates, along with other critical information. After decades of exposure and use, all of the water quality equipment are nearing the end of their useful life.

The project will replace older, radio transmitter technology with a fiber optic system; replace and install new instruments, including new electrical hubs and communications panels; construct a large vault structure to install new flow meter technology, making the meters more accessible to staff; and improve the integrity of the weir structure. Cascading water from the weir has eroded the existing rock riprap into the bay mud. Several feet of new riprap will be installed to protect the structure and prevent further erosion.

• Current Stage: Construction and Commissioning
• Consultant: AECOM
• Contractor: Anvil Builders Inc.
• Adopted Budget: $10 million
• Expected Beneficial Use: November 2023

The guard shack at the main entrance to the RWF is showing signs of age and no longer meets current ADA requirements. This project will replace the guard shack with a new guard shack meeting ADA requirements. The project’s scope also includes various improvements to the surrounding main entrance area.

This project is being delivered using a Design-Bid-Build Fast-Track model.

  
(Image caption: The steel skeleton of the new main entrance early in construction.)

The project will install:

• A new guard shack with a restroom and a security monitoring workstation.
• A closed-circuit television (CCTV) system with face recognition and license plate detection.
• An improved lighting system in and around the vicinity of the main entrance.
• Improved traffic circulation, utility relocation, new asphalt pavement and a pedestrian walkway.

• Current Stage: Construction & Commissioning 
• Consultant: Jacobs Engineering Group
• Contractor: W.E. Lyons Construction Co.
• Adopted Budget: $14 million
• Expected Beneficial Use: June 2026

The RWF is located within a Federal Emergency Management Agency (FEMA) flood zone and is vulnerable to both regional and localized flooding. A 2015 Flood Protection Study identified deficiencies in the RWF's existing storm drain system. Subsequent condition assessments have confirmed these deficiencies. And, alternative analyses have identified options for protecting critical infrastructure, access routes, and staff.

This project will:

• Rehabilitate existing stormwater pump stations.
• Replace deteriorated sanitary and storm drain pipes.
• Clean and flush additional sanitary and storm drain pipes.
• Add drainage swales and storage volume where viable.
• Waterproof tunnel entrances.

• Current Stage: Construction & Commissioning
• Consultant: AECOM
• Contractor: Ranger Pipelines, Inc.
• Adopted Budget: $13.9 million
• Expected Beneficial Use: December 2023

The RWF has approximately 67,000 linear feet (LF) of process pipes that carry gas, liquids, sludge, air, steam, and other process streams across various treatment areas. These pipes vary in age, material, size, condition, reliability, and redundancy. 

A 2015 desktop study of the process pipes identified 16 pipe systems, totaling 21,000 LF, that are at high risk of failure. Subsequent condition assessments confirmed that two of the highest priority pipes - the 78-inch settled sewage (SES) and the 96-inch SES pipes showed evidence of severe crown corrosion. Due to the severity of deterioration and the criticality of these pipe segments, the City decided to expedite their rehabilitation under separate projects. The 78-inch SES was rehabilitated in 2018 under the Digester and Thickener Facility Upgrade project. The 96-inch and 87-inch x 136-inch Settled Sewage pipes were rehabilitated in fall 2020. Rehabilitation of the remaining high priority pipes is delivered in three phases.

Phase 1: Completed January 2022

Phase 2: Completed November 2024

Phase 3:

• Current Stage: Construction and Commissioning
  
• Consultant: Black & Veatch
  
• Contractor: Michels Trenchless 
  
• Adopted Budget: $32.5 million
  
• Expected Beneficial Use: January 2027