Desalination Plants & California Water Supply

Are desalination plants a viable solution to relieving water stress and increasing access to potable water?

What is Desalination?

Desalination is the process of removing salts or other minerals and contaminants from seawater, brackish water, and wastewater effluent and it is an increasingly common solution to obtain fresh water for human consumption and for domestic/industrial utilization ( Asadollah et al, 2017 ).

Can desalination end global water shortages?

Reverse Osmosis

In reverse osmosis desalination, water is taken from the sea and receives a first treatment to eliminate impurities, oil, seaweed, rubbish, and so on. Once free of organic substances, the saltwater can be subjected to reverse osmosis. After the filtering, we have two streams: one brine and the other freshwater. The brine solution is diluted before being returned to the sea, avoiding high concentrations of salt which could harm the ecosystem. The freshwater passes through a remineralization and chlorination process, after which it is stored in tanks and then sent to the distribution network for consumption ( Sustainability for all ).

Why is Desalination needed?

The scarcity of freshwater resources and the need for additional water supplies is already critical in many arid regions of the world and will be increasingly important in the future. Many arid areas simply do not have freshwater resources in the form of surface water such as rivers and lakes ( USGS ).

Benefits

--Provides accessible drinking water.

--Desalination can help preserve habitats reliant on freshwater sources like groundwater, rivers, and lakes.

--Provides water to the agricultural industry.

--Desalination uses ocean water which is in unlimited supply ( Green Directory ).

Environmental Costs

--Most forms of desalination are energy-intensive. Desalination has the potential to increase fossil fuel dependence, increase greenhouse gas emissions, and exacerbate climate change if renewable energy sources are not used for freshwater production

--Desalination surface water intakes are a huge threat to marine life. Mature fish, larvae, and other marine life can be significantly injured or killed when they become trapped or sucked into open water surface intake pipes.

--The State Water Resources Control Board estimates that open ocean intakes used by coastal power plants in California kill 70 billion fish larvae and other marine life on an annual basis. These same open ocean intakes are being proposed for use at desalination plants throughout California.

--Brine waste also poses a potential threat to marine life and water quality, as it contains dangerously high concentration of salts and other minerals. Because of its high density and salinity, brine waste can accumulate in and around disposal areas smothering bottom dwelling species and significantly altering coastal ecosystems ( Heal the Bay ).

Economic Costs

Salt quickly dissolves in water and forms a chemical bond that is not easy to break. Therefore, there is no easy or cheap way to take away salt and chemicals to produce potable water. Many different types of technologies and large amounts of energy is required to run a desalination facility. The biggest saltwater desalination plant in California spent over a billion dollar in technologies and building the facility. "Operation costs account for two-thirds of water production costs, while one-third is based on capital cost depreciation. Energy accounts for 50% of the operation cost when membranes, pumps and energy recovery devices with standard efficiency are used" (Economics of Desalination — Reducing Costs by Lowering Energy Use, 2004). If desalination plant was more financially feasable, we would see more of them globally.

Drought in California

It is no surprise that the West has been experiencing the worst climate since human civilization. As drought persists and warmer years ahead of us, we need to prepare ourselves for the worse. The reservoirs in California, and other states in the West, have been observed an annual decline of water stored in reservoirs. Only a few have been maintaining their historical average mark, while most are only filled to about 40% of its annual average.

Major Reservoirs in California

California Saltwater Desalination Plants

In an arid state with very large amounts of agricultural activites, California is one of the states that is suffering the most due to climate change and drought. Today, California has 12 existing successful saltwater built activities its gallonsdesalination plants all along it's coasts (most are saltwater, while some are brackish desalination facilities). The Claude "Bud" Lewis Carlsbad Desalination Plant is the largest and most succesful facility in the western hemisphere. It was builit in 2015 and has since been extracting billions of gallon of salwater from the Pacific Ocean and providing fresh water for 10% of San Diego County's water supply (SDCWA).

  1. Moss Landing Power Plant
  2. Marina Coast Water District Desalination Plant
  3. Sand City Desalination Plant
  4. Monterey Bay Aquarium
  5. Morro Bay Desalination Plant
  6. Morro Bay Power Plant
  7. Diablo Canyon Nuclear Power Plant
  8. Gaviota Oil Heating Facility
  9. Charles E. Meyer Desalination Facility
  10. Pebbly Beach Desalination Plant
  11. San Nicolas Island Desalination Plant
  12. Carlsbad Desalination Plant

Carlsbad, CA: Public-Private Partnership

The Carlsbad desalination plant was approved for commercial operation back in 2012. The Carlsbad plant is privately, investor-owned corporation; the Poseidon Water. The Poseidon Water and San Diego Country Water Authority came into an agreement that allowed the city to purchase up to 56,000 acre-feet of desalinated seawater per year which is called the Water Purchase Agreement. This allowed the citizens of San Diego to purchase water through the government at an affordable rate.

Carlsbad Desalination Project

The plant follows a strict guidelines to ensure the quality of the water. The Water Authority purchases water from the plant at pre-defined prices. If the water does not meet quality requirements specified in the agreement, the Water Authority does not pay. The agreement also specifies that the Water Authority has the right to ensure that the plant is operated and maintained in a safe, efficient manner consistent with industry standards. At the end of the agreement’s 30-year term, the Water Authority may purchase the plant for $1.

Today the plant provides 50 million gallons of water per day to the San Diego County.

Although it may seem like 50 million gallons of water is a lot, it is not enough. There are about 3.3 million people living in San Diego County. The plant provides approximately 400 thousand people per day.

References

California, parched West remain divided over seawater desalination. (n.d.). Retrieved May 2, 2022, from  https://www.usatoday.com/story/news/nation/2022/02/22/california-seawater-desalination-western-drought/6896322001/ 

Can desalination end global water shortages? - YouTube. (n.d.). Retrieved May 2, 2022, from  https://www.youtube.com/watch?v=9R3GNOVajAs 

Desalination | U.S. Geological Survey. (n.d.). Retrieved May 2, 2022, from  https://www.usgs.gov/special-topics/water-science-school/science/desalination 

Mickley, A. (n.d.). Updated and Extended Survey of U.S. Municipal Desalination Plants. 56.

Ocean Plan Requirements for Seawater Desalination Facilities | California State Water Resources Control Board. (n.d.). Retrieved May 2, 2022, from  https://www.waterboards.ca.gov/water_issues/programs/ocean/desalination/ 

Water Year 2021: An Extreme Year. (n.d.). 12.

What is reverse osmosis desalination? (n.d.). Retrieved May 2, 2022, from  https://www.activesustainability.com/water/what-is-reverse-osmosis-desalination/ 

Major Reservoirs in California

Carlsbad Desalination Project