Produced Water Facility at Southern California Oil Field Features the First-Ever Installation of OPUS®

Southern California Refinery


Chevron's San Ardo oil field in Southern California recovers more than 10,000 barrels of heavy oil each day. The extraction process results in significant volumes of produced water that requires treatment and disposal. Chevron engaged Veolia's water treatment technology, engineering and operations experts to provide a solution for sustainably treating the produced water for surface discharge, while enabling enhanced oil production. 

Southern California Refinery Case Study
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To achieve this, Veolia provided Engineer-Procure (EP) services and operates a produced water management facility at this oil field that features the first-ever installation of OPUS® (Optimized Pretreatment and Unique Separation) technology. Developed by Veolia Water Technologies, OPUS® is a reliable and robust process for successfully treating produced water for surface discharge.  The reliable operations & maintenance of the plant is backed by a Veolia performance guarantee.


The process of extracting oil from the ground generates a volume of water that can range from 10 to 20 times the oil production rate. Historically, a portion of this water had been recycled and softened for reuse in steam generation, with the remainder going to local EPA class II injection wells for disposal. However the injection zone capacity is limited, which constrains full field development and daily production levels.

The raw produced water for this oil field is 200°F, and contains about 25 ppm free oil, 80 ppm TOC, 240 ppm silica, 26 ppm boron, 240 ppm hardness and 6,500 ppm Total Dissolved Solids (TDS). The project goal was to reduce the feed water TDS to less than 510 ppm and boron to less than 0.64 ppm for discharge, while achieving 75% water recovery across the treatment system and minimizing the volume of produced water requiring re-injection. For steam generation, the project goal was to reduce the feed water hardness to less than 2 ppm total hardness as CaCO3.


Veolia provided the first produced water facility in the world to use its OPUS® technology, a multiple-treatment process that removes contaminants sufficiently to meet the established requirements for discharge. The treated water is released through shallow wetlands into aquifer recharge basins that replenish local water resources. 

The technology and services provided by Veolia enables the plant's entire water cycle to be managed in a truly sustainable way, while simultaneously expanding oil production capacity. Since its commissioning in 2008, the water treatment facility has been operated by Veolia, under contract with Chevron.  Veolia provides daily operations and oversees the facility's maintenance according to an established performance guarantee. Four key areas of service include: 

  • Daily plant management and handling of 150,000 barrels of water involving a chain of treatment processes. The 50,000 barrels of treated water is discharged to constructed wetlands that drain into aquifer recharge basins. 
  • On-site and off-site engineering support to achieve improved operations. For example, the devastation caused by hurricanes in 2008 and 2005 resulted in a shortage of hydrochloric acid used in the regeneration process of the water softeners that are part of the OPUS technology. Veolia developed a different concentration of the formula to maintain ongoing operation of the facility and to reduce its reliance on hydrochloric acid while maintaining operational efficiency. 
  • Independent pilot studies at the plant and in the laboratory to identify new ways to optimize plant operations, prevent failure and continue to implement sustainable processes while maintaining oil production capacity. 
  • Troubleshooting as required, available onsite 24/7, to maintain operational efficiency.


  • Veolia's OPUS® technology and operational model allows Chevron to minimize deep well injection disposal of its produced water, and enabled production expansion into an idled, previously developed portion of its production field. 
  • Improved softened water quality is provided to the steam generators.
  • Produced water is consistently treated to levels that allow for surface discharge to replenish local water resources. 
  • Facility operations are backed by Veolia's performance guarantee for the life of the operating contract and ensures continual system optimization. 


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