Conservation groups worry that desalination intake pumps would kill natural life that’s a foundation for the underwater food chain and the excess salt desalination discharges back into the ocean.
More than 80 percent of California faces extreme drought, a condition that’s not likely to improve on its own anytime soon. City governments have turned to science to solve the problem by scaling up water recycling technology and deploying systems that extract salt from the Pacific Ocean in a process called desalination. The methods tap into two seemingly unlimited resources — the vast, regenerating sea, and human wastewater that is cleansed and reused indefinitely in a potentially endless cycle.
Carlsbad is home to what’s arguably California’s most high-profile project to extract salt and impurities from the ocean to produce more potable water for drinking and washing, and utility and softened water for agricultural and other constructive uses. The San Diego County Water Authority and the company Poseidon are building the Carlsbad Desalination Plant at the Encina Power Station to push ocean water through a semi-permeable membrane to separate salt particles from water molecules in a process called reverse osmosis. The county and Poseidon plan for the plant to provide 50 million gallons of desalinated water to San Diegans each day once completed.
The plant will be live by 2016, and Poseidon plans for another desalination project to go live in Huntington Beach in 2018. They’re part of 17 desalination plants currently in development along the California coast to extract water from the Pacific Ocean. Poseidon claims that once the $1 billion Carlsbad project is complete, it will be the Western Hemisphere’s largest desalination plant. The possible construction of additional California desalination plants will likely depend on its success or failure. Recently, United States desalination plants have been getting attention, but Africa and the Middle East have operated plants for years to solve local water resource problems.
San Diego plans to deploy a plant that will supply the area with 15 million gallons of recycled wastewater by 2023, and will build up to where it supplies 83 million gallons of pure water by 2035. Purification methods will include reverse osmosis as well as ultraviolet disinfection, a process where ultraviolet light is shined on water to disinfect it.
Orange County employs similar methods to “recycle” sewage water into a near-distilled state. The process uses less energy than both ocean water desalination and the energy required to import water from Northern California. The county began its program on a smaller scale in 2008 and is undergoing a $150 million dollar expansion, which will be completed by 2015.
California is set on deploying these strategies to solve the drought problem. They’re great in theory as potentially permanent solutions, as public employees can keep recycling wastewater over and over again, and the ocean itself will always exist to be desalinated thanks to the planet’s evaporative weather cycle that replenishes Earth’s seas.
But these solutions may not come without cost. Conservation groups have worried that Carlsbad’s desalination intake pumps would suck in fish eggs and invertebrates, killing natural life that’s also a source of food for other marine creatures and a foundation for the underwater food chain. They’re also concerned about the excess salt desalination discharges back into the ocean, infusing seawater with too much salt in some areas for creatures to survive. The government approved the Carlsbad plant under the condition that Poseidon build new wetland areas to offset potential damage from their plant. Yet if California constructs multiple desalination plants along its coast, it’s unclear how much damage they could do to coastal ecosystems in the future.
The Carlsbad plant website claims that cost has impeded more desalination plant construction in the United States in the past, though no financial figures were offered save for the plant’s $1 billion price tag. The San Diego County Water Authority partnered with Poseidon to finance the plant because Poseidon is a private company with enough capital to cover the substantial upfront costs, which would be too much for most local governments to support alone. Desalination technology has also traditionally been expensive, though recent technological advancements have allowed them to operate more cheaply today.
The media has labeled wastewater recycling projects like Orange County’s and San Diego’s “toilet to tap,” a bad name from a PR standpoint as it evokes unsavory images about the origins of the water people could be drinking and bathing with. But the Wichita Falls government in Texas is adopting a water re-use plan despite the derision because drought problems extend to other Western states beyond California.