DATE: January 25, 2023
TO: Council Infrastructure Committee
FROM: Director of Public Works
SUBJECT: Cargill Mixed Sea Salts Processing and Brine Discharge Project – Information and Discussion
RECOMMENDATION
That the Council Infrastructure Committee (CIC) reviews this report and the presentation from Cargill Incorporated (Cargill) and provides comments.
SUMMARY
Cargill is proposing a project that would enable enhanced processing and removal of mixed sea salts (MSS) in existing Cargill salt ponds by harvesting additional liquid bittern (concentrated magnesium chloride brine) from the MSS as a commercial product. The residual MSS solids would be dissolved in the ponds using San Francisco Bay (Bay) water. The resulting brine would then be transferred to East Bay Dischargers Authority’s (EBDA) combined effluent pipeline for discharge into the Bay. The brine pipeline is proposed to run through Hayward, as well as Newark, Fremont, Union City, and San Lorenzo, to the Bay. As part of this project, Hayward is working with Cargill on the design and installation of the recycled water main in proximity to the portion of the brine pipeline that would run through the City to serve additional recycled water customers, thereby enhancing the City’s local water supply. All costs associated with the brine pipeline and recycled water main that is proposed in Hayward would be paid for by Cargill. The project is currently undergoing review in accordance with the provisions of the California Environmental Quality Act (CEQA).
Cargill’s team is here this evening and ready to present their project to the Committee and receive feedback.
BACKGROUND
EBDA is a Joint Powers Public Agency (JPA) consisting of five local agencies - City of Hayward City of San Leandro, Oro Loma Sanitary District, Castro Valley Sanitary District, and Union Sanitary District. EBDA owns and operates three effluent pump stations, a dichlorination facility, and combined effluent pipeline/force main and outfall system to manage treated effluent from its member agencies’ wastewater treatment plants and discharges the effluent through its common outfall and diffuser into a deep-water portion of the central Bay under a National Pollutant Discharge Elimination System (NPDES) permit.
Cargill operates a solar sea salt production facility (Solar Salt Facility) in Newark, California. The Solar Salt Facility produces sodium chloride (NaCl, i.e., table salt) and liquid bittern through solar evaporation of Bay water in a series of salt ponds along the margin of the Bay. After the majority of the NaCl is precipitated through a process of concentration and evaporation, it is moved to Cargill’s adjacent salt refinery, where it is further processed and packaged to individual customer’s specifications. The remaining brine and precipitated salt crystals, which primarily contain salts that are more soluble than NaCl, are referred to as mixed sea salts or MSS. The MSS remain in the salt production process, where further NaCl may be recovered and liquid bittern is harvested to produce additional commercial products used for road de-icing and dust suppression, animal feed, as well as other products.
In 2019, EBDA was approached by Cargill with a proposal to discharge brine from Cargill’s Solar Salt Facility in Newark, California, via EBDA’s transport pipeline and outfall to the Bay. Cargill manages a vast network of salt ponds separated from the Bay by a system of berms. MSS are what remains after product streams have been harvested from sea water. The ponds containing the MSS are adjacent to the Bay and could be impacted in the future by significant storms and King Tides coupled with sea level rise. Cargill is taking a proactive approach to protecting the Bay through enhanced commercial processing and accelerated removal of its inventory of MSS by sending MSS brine through the EBDA system.
Cargill, in conjunction with EBDA, contacted Hayward in 2022 regarding a proposed brine pipeline route that would run through Hayward as part of the proposed project. Hayward staff have been in discussions with Cargill, their engineering consultants Jacobs, as well as EDBA regarding the pipeline routes and the addition of a recycled water main adjacent to the pipeline through Hayward only.
DISCUSSION
The proposed project would involve modifications within Cargill’s Solar Salt Facility, including new pipelines and pumping facilities, and construction of approximately 16 miles of new underground pipeline running through Newark, Fremont, Union City, Hayward, and San Lorenzo, primarily within roadway rights-of-way, to connect to EBDA’s outfall system on the site of the Oro Loma Sanitary District/Castro Valley Sanitary District Water Pollution Control Plant in the community of San Lorenzo. The brine would then be blended with effluent from EBDA’s member agencies and discharged through EBDA’s deep water outfall to the Bay.
It is anticipated the brine would be discharged to the EBDA system at an average rate ranging from 1 to 2 million gallons per day (mgd), which would take approximately 10 to 20 years, respectively, to discharge all of the brine. Discharge of the brine by Cargill to the EBDA system would be subject to an agreement between EBDA and Cargill. The EBDA JPA term expires on June 30, 2040. Therefore, the proposed project would either terminate on or before that date, or could continue under a renegotiated agreement.
As a component of this project, Hayward is working with Cargill on the design and installation of a recycled water main adjacent to the portion of the brine pipeline that would run through the City. The recycled water main would serve additional recycled water customers located in the predominately commercial and industrial, western portion of Hayward. Through the use of recycled water, potable water will be preserved for uses that require drinking water quality, thereby, enhancing the City’s local water supply. All costs associated with the brine pipeline and recycled water main design, environmental review, and construction would be paid for by Cargill.
A Draft Environmental Impact Report (DEIR) has been developed for the project in accordance with CEQA requirements. The DEIR was issued on January 4, 2023, for a 45-day review period with written comments due to EBDA on February 17, 2023. A public meeting will be held via Zoom on January 24, 2023.
Cargill’s team is here this evening and ready to present their project to the Committee and receive feedback.
ECONOMIC IMPACT
The delivery of recycled water can provide cost savings to the customers, including businesses that would receive recycled water. The benefit of this project to the community is that it will ensure a reduction in potable water use, allowing for greater diversity and reliability in the City’s water supply especially during droughts.
FISCAL IMPACT
The costs associated with this project should be fully funded by Cargill.
STRATEGIC ROADMAP
This agenda item is an informational item and does not relate to one of the Council’s six Strategic Priorities.
SUSTAINABILITY FEATURES
The community could benefit from the extension of its existing recycled water main to provide recycled water to additional customers. This would provide greater diversity and reliability of Hayward’s water supplies, especially during water emergency periods. Recycled water provides a locally sustainable and drought-tolerant water supply for commercial irrigation and industrial customers, enhancing the City’s water supply. It also reduces the volume of wastewater and associated nutrients and residual pollutants discharged to the Bay, which may be required to meet increasingly stringent discharge regulations.
PUBLIC CONTACT
The DEIR was issued on January 4, 2023, for a 45-day review period. Written comments are due to EBDA by February 17, 2023. A public meeting is planned to be held by EBDA via Zoom on January 24, 2023, at 6:00 pm.
NEXT STEPS
City staff will continue to work with Cargill staff and provide feedback on the brine pipeline route and adjacent recycled water main.
Prepared by: Cheryl Muñoz, Water Resources Manager Recommended by: Alex Ameri, Director of Public Works Approved by:
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Kelly McAdoo, City Manager