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  • Project type
    Project type Reuse
  • Area served
    Area served N/A (Demonstration plant)
  • Population served
    Population served N/A (Demonstration plant)
  • Status
    Status Complete (2014)

California has suffered severe and devastating drought conditions in recent years. To combat periods of severe drought, there has been an effort to implement water conservation measures and consider innovative reuse solutions across the state of California.

To diversify its water supply, while also reducing its dependence on imported water, Padre Dam Municipal Water District embarked on an advanced water treatment plant project to explore a new source of water in Santee, California.

The new facility was constructed to treat secondary effluent from a wastewater treatment plant in the District. The treated water was used for demonstration and testing purposes, to ensure it exceeded the stringent California Public Health Department’s draft regulations, allowing the facility to provide water to residents.

In the future, the District hopes to be able to expand the facility, to construct a full-scale plant to provide up to 64 MLD (14-17 MGD US) of treated water with indirect potable reuse potential.

With the necessary approvals to proceed, treated water would be pumped to augment surface water levels. It would then be withdrawn, treated again, and then distributed as drinking water to customers.

The Advanced Water Purification Demonstration Project was funded through a three million dollar ‘Proposition 50’ grant from the Department of Water Resources.

With our global Centre of Excellence for Desalination and Membrane Treatment in California, it has been a pleasure to support this progressive local demonstration project, which has the potential to reduce Padre Dam’s dependence on imported water from the Colorado River hundreds of miles away.

Richard White, Senior Vice President, Biwater Inc., United States


Technical Summary:

Membrane treatment capacity:

  • 378 m3/day
  • 0.378 MLD
  • 100,000 US gallons per day

Overview and considerations:

  • Advanced water purification technologies were utilised in the construction and installation of this indirect potable reuse facility
  • The advanced treatment processes included in the design are: Chlorine disinfection; coagulation; ultrafiltration; high recovery reverse osmosis; advanced oxidation
  • To deliver these advanced treatment processes on a fast-track basis, the following system elements were required on-site for installation and commissioning: Field pumps; chlorine contactor; chemical dosing systems; automatic strainers; ultrafiltration system; reverse osmosis system; reverse osmosis concentrator system for 92.5+% recovery; advanced oxidation process system (using ultraviolet light and chemical oxidation); programmable logic controller, field instrumentation and electrical panels; clean-in-place system
  • Biwater provided a complete turnkey design and supplied and commissioned all process, mechanical, electrical and control components for the plant
  • Biwater was chosen for its ability to supply a fully integrated system on a fast-track delivery, supporting Padre Dam’s efforts to initiate proof of concept and testing activities as soon as possible