desalination facilities and brine disposal
State Water Board staff is developing an amendment to the Ocean Plan that would address issues associated with desalinization facilities and the disposal of brine discharges from other sources. Desalination facilities and brine disposal was discussed as Issue No. 4 in the 2011-2013 Triennial Review Workplan. The issue has been identified as very high priority for the State Water Board to address, because several new desalination facilities have been planned along the California coast to augment existing potable water supplies.
During the process of ocean desalination, salt and minerals are removed from salt water to produce fresh water. Other projects, such as brackish groundwater desalination and wastewater treatment/recycling, also generate brine discharges. The salt, minerals, and other compounds are discharged as hyper-saline brine. Brine is denser than the receiving ocean water and, depending on discharge methods, may settle on the ocean bottom. Accumulation of brine on the seafloor may have an adverse effect on marine organisms.
Currently, the Water Boards regulate brine discharges from these types of facilities through the issuance of National Pollutant Discharge Elimination System (NPDES) permits that contain conditions protective of aquatic life. However, the Ocean Plan does not yet have an objective for elevated salinity levels in the ocean, nor does it describe how brine discharges are to be regulated and controlled, leading to permitting uncertainty. The Ocean Plan also does not address possible impacts to marine life from intakes for desalination facilities.
The planned Ocean Plan amendment is currently envisioned to have the following components: 1) a “narrative” objective for salinity, 2) provisions to minimize impacts to marine life from desalination plant intakes, and 3) implementation provisions. State Water Board staff anticipates that the Ocean Plan amendment will be completed by late 2013.
None at this time.
As part of the development of the amendment, staff has initiated three studies to gather scientific data and get technical input and scientific recommendations on key issues. The two expert panels have finalized their findings and recommendations.
High-Salinity Sensitivity Study
The West Basin Municipal Water District (WBMWD) High Salinity Sensitivity Study (HSS Study) comprehensively evaluated the potential short-term and long-term exposure effects of high salinity discharges from the WBMWD ocean water desalination demonstration facility (OWDDF) on aquatic organisms representative of communities indigenous to various near shore environments in Southern California. Short-term effects were evaluated using Whole Effluent Toxicity (WET) bioassays developed by the U.S. Environmental Protection Agency (USEPA) to quantify the magnitude and threshold of potential biological effects of discharges (e.g. treated wastewater). Both acute toxicity (mortality effects) and chronic toxicity (mortality + sublethal effects) bioassays were performed by a state accredited bioassay laboratory. Long-term effects were evaluated using mesocosm procedures performed at the OWDDF by exposing multiple organisms for eight weeks to ambient seawater and diluted brine flows from the OWDDF in large aquaria constructed to simulate the OWDDF discharge environment.
- High-Salinity Sensitivity Study Short-and Long-Term Exposure Assessments
Salinity Toxicity Studies
Researchers at the Marine Pollution Studies Laboratory at Granite Canyon will determine the tolerance of Ocean Plan test species to various concentrations of hyper-saline brine. All toxicity tests will follow the U.S. EPA methods. The results of the tests will be used to calculate no observed effect concentrations (NOECs), lowest observed effect concentrations (LOECs), and median lethal or median effects concentrations (LC50 or EC50) for each test protocol and endpoint. Toxicity tests will also be conducted using a brine effluent sample from a desalination facility.
- Hyper-Salinity Toxicity Thresholds for Nine California Ocean Plan Toxicity Test Protocols
Expert Panel on Intake Impacts and Mitigation
The State Water Board contracted with the Moss Landing Marine Laboratory to establish an expert panel to address issues associated with minimizing and mitigating intake impacts from power plants and desalination facilities. The panel members were Dr. Michael Foster, Dr. Greg Cailliet, Dr. Jim Callaway, Dr. Pete Raimondi, and Mr. John Steinbeck. The panel met on August 8, 2011 and on November 15, 2011. A public meeting was held March 1, 2012 at the Moss Landing Marine where panel members presented their recommendations and took questions and comments from the public on the panel’s Draft Report. Updates were given on the other two studies. The panel members deliberated and made changes to their report, which was finalized on March 14, 2012 Expert Review Panel on Intakes: Final Report.
Expert Panel on Impacts and Effects of Brine Discharges
The State Water Board contracted with the Southern California Coastal Water Research Project (SCCWRP) to establish a panel of experts in the fields of oceanography, plume modeling, ecotoxicology, and marine ecology to answer the following questions related to brine discharge:
- What are the potential environmental impacts?
- What disposal strategies will minimize impacts from brine discharges?
- What models should be applied to predict how brine plumes will behave?
- Can cumulative water quality effects associated with multiple brine plumes be evaluated with models?
- What are appropriate monitoring strategies for brine discharges?
A public meeting was held July 5, 2011 in Sacramento to describe the project and solicit input regarding panel members and issues. A panel of experts was selected and input from the public has been posted online. The panel met several times to develop recommendations for the State Water Board. A public meeting was held on December 8-9, 2011. The panel met on February and a Final Report with their findings and recommendations was finalized on
- Stakeholder Meeting at Moss Landing Marine Laboratories - January 30, 2013
Discuss amendments to the Water Quality Control Plans for Ocean Water and Enclosed Bays and Estuaries to Address Desalination Facilities and Brine Disposal
- Public Workshop - August 22, 2012
Amendments to the Water Quality Control Plans for Ocean Waters and Enclosed Bays and Estuaries to Address Desalination Facilities and Brine Disposal
- CEQA Scoping Meeting - March 30, 2012
- Stakeholder Meeting - April 18, 2011