Delta Diablo (District) prioritizes the repair and replacement of its equipment and facilities via a comprehensive Capital Improvement Program (CIP).  This reflects strong fiscal responsibility ensuring successful, long-term rehabilitation of our infrastructure and investment of ratepayer funds to provide essential community wastewater services to residents and businesses in Antioch, Bay Point, and Pittsburg.

Shore Acres Forcemain Repair

The Shore Acres Forcemain Repair Project was initiated to address infrastructure concerns associated with the 0.9 mile 16-inch discharge forcemain from the District’s Shore Acres Pump Station in Bay Point. The District has retained Black & Veatch to provide engineering design services for this project. The project primarily involves installing a new forcemain and rehabilitate the existing 16-inch forcemain to meet buildout conditions and ensure system resiliency. 

Point of Contact:  Thanh Vo, Senior Engineer, thanhv@deltadiablo.org

Project Status: Design

Anticipated Start of Construction: Fall 2026

Estimated Constructuion Cost: $10M-$12M      

Secondary Process Improvements Phase 1 

The Secondary Process Improvements Project has been initiated to address aging infrastructure at the wastewater treatment plant, provide additional secondary treatment capacity to support population growth within the service area, and incorporate advanced nutrient removal technologies into plant operations.

Phase 1 of the project will focus on decommissioning the existing trickling tower filters and constructing new aeration basins to ensure reliable secondary treatment performance. These improvements will also support compliance with the nutrient removal limits established under the 2024 San Francisco Bay Nutrients Watershed Permit, with final limits expected to take effect in 2034.

To support these upgrades, several ancillary facilities will also be constructed, including a new secondary clarifier, blower building modifications, secondary solids thickening improvements, and associated pumping stations.

CEQA Initial Study/Mitigated Negative Declaration

The District has completed environmental review for the project in accordance with California Environmental Quality Act (CEQA). The Initial Study/Mitigated Negative Declaration (IS/MND) and related project information are available at the State Clearinghouse website: https://ceqanet.lci.ca.gov/2024080857

Point of Contact:  Sean Williams, Associate Engineer, seanw@deltadiablo.org 

Project Status: Design

Anticipated Start of Construction: Fall 2026

Estimated Construction Cost: $125M-$145M

Cogeneration System Improvements

The District operates an existing cogeneration system at the Wastewater Treatment Plant capable of generating heat for the anaerobic digesters as well as producing energy to reduce the amount of power needed to be purchased from the grid to run the plant. The existing gas treatment system and cogeneration engine are nearing the end of their useful life and require replacement. The Cogeneration System Improvements project will include the replacement of the existing cogeneration engine and gas conditioning equipment as well as upgrades to electrical and control infrastructure. The project is eligible for federal tax credits for the District under the Inflation Reduction Act, but specific requirements must be met by both the District and Contractor under the IRS regulations regarding labor, scheduling, and domestic content to maintain the integrity of the Inflation Reduction Act. Projects like the Cogeneration Systems Improvement project are instrumental in enhancing the District’s resource recovery capabilities and promoting more efficient and reliable performance.

Point of Contact:  Stephen Cardiel, Associate Engineer, stephenc@deltadiablo.org

Project Status: Construction

Antioch Pump Station and Conveyance System Improvements

The District established the multi-year Antioch Pump Station and Conveyance System Improvements Project to assess the Antioch Conveyance System, which consists of two 24-inch force mains (i.e., AFM 101 and AFM 102). The initial phase will identify portions of the force mains that need to be repaired immediately to ensure near-term operational reliability. The future phases will include conducting design activities related to the Antioch conveyance system, including the Antioch and Bridgehead pump stations, to develop a major project to address deficiencies in these systems to ensure long-term operational reliability. The District is currently pursuing the development of an alternative project approach (e.g., progress design-build) to mitigate project risks and potentially accelerate the overall project completion schedule. The estimated project cost has been updated to $4 million in the District’s new 5-year Capital Improvement Program for FY25/26-FY29/30.

Point of Contact:  Thanh Vo, Senior Engineer, thanhv@deltadiablo.org

Project Status: Planning (Predesign)

Anticipated Start of Construction: Summer 2027

Estimated Construction Cost: $8M-$20M

Manhole, Gravity Interceptor, and Easement Road Improvements Phase 2

The 2020 Final Report for the Facility Condition Assessment Project identified the assets associated with the Shore Acres Interceptor system as a high priority. Failure of this system with limited site access can lead to sanitary sewer overflows and potential adverse public health and environmental impacts due to insufficient and/or unreliable conveyance capacity. As a result, in 2022, the District initiated the multi-phase Manhole, Gravity Interceptor, and Easement Road Improvements Project to address infrastructure needs, conduct sewer condition assessment, and improve access to critical assets in the Shore Acres Interceptor system. Phase 1, currently in construction, primarily involves planning, designing, and constructing of approximately 30 critical manholes and rehabilitating approximately 200 feet of 20-inch reinforced concrete pipe (RCP) and 650 feet of 30-inch RCP using structural cured-in-place (CIPP) liner. The Project is the next phase of the Phase 1 project that will address the remaining infrastructure needs in the Shore Acres Interceptor System and also include the evaluation and rehabilitation of the Willow Pass Interceptor and the two junction structures located at the intersection of Arcy Lane and the Pittsburg-Antioch Highway near the entrance to the District’s WWTP. The District’s new 5-year Capital Improvement Program (CIP) for FY25/26-FY29/30 includes the $4 million Phase 2 project.

Point of Contact:  Thanh Vo, Senior Engineer, thanhv@deltadiablo.org

Project Status: Design

Anticipated Start of Construction: Fall 2026

Estimated Construction Cost: $10M-$12M