About Us

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Delta Diablo (District) provides water resource recovery services for the City of Antioch, the City of Pittsburg, and the unincorporated community of Bay Point, serving a population of nearly 200,000. The water resource recovery services consist of conventional treatment of wastewater, recycled water production and distribution, pollution prevention, energy recovery, beneficial reuse of biosolids, street sweeping, and household hazardous waste collection. The District’s largest asset is its staff of dedicated employees who keep the system running 24 hours a day, 365 days a year.



The District service area encompasses 54 square miles and the District operates and maintains the following components:

  • 14 miles of sewer forcemain and 14 miles of interceptors
  • 6 pump stations and 5 equalization storage facilities with 4 million gallons (MG) of storage
  • 43 miles of sewer lines in the Bay Point collection system (Antioch and Pittsburg own and operate approximately 130 miles and 300 miles, respectively, of their own satellite systems that feed into the District)
  • Wastewater Treatment Plant with a 2.2 MG flow equalization basin and 12 MG of storage
  • Recycled Water Facility (RWF)
  • 16 miles of recycled water pipeline

The conventional treatment process consists of screening, grit removal, primary and secondary clarification, biological treatment by trickling towers and/or aeration basins, chlorination, and de-chlorination, as shown in the figure below. Solids are anaerobically digested, centrifuged, and beneficially reused as fertilizer. The wastewater treatment plant has an average dry weather design capacity to provide conventional level treatment for up to 19.5 million gallons per day (MGD). Treated wastewater is discharged through a deep water outfall to New York Slough.

DDSD Treatment Process Schematic


The District's core services include:



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