In the midst of one of one of its most severe droughts on record, the state of California is faced with an unprecedented issue: its supply of clean and potable water is hovering over insufficiency. Rates for potable water throughout local and state-wide agencies have increased at alarming rates. How, then, we are left to wonder, is the state going to secure a safe and reliable water source for the foreseeable and unforeseeable future? As the Danish author Isak Dinesen put it “The cure for anything is salt water – sweat, tears, or the sea.” Novelties aside, Dinesen was onto something. Desalination, the process of removing minerals from saline water, is increasingly becoming a viable option for water agencies and consumers living through and beyond the current drought state of emergency. The focus of this essay is, to: discuss the process of desalination, to delve into the workings of the Claude “Bud” Lewis Carlsbad Desalination Plant, and to cover some of the benefits and drawbacks of desalination of seawater.
Desalination, at its core, is a relatively simple process. In short, a desalination plant takes regular seawater and converts it into safe, clean, and potable water. The seawater is brought into the desalination plant via pipes that are installed under the ocean’s surface. Water is brought into the plant, into several levels of treatment. The seawater is filtered through coal (anthracite), sand, and gravel in order to remove algae, organic material, and other particles. During secondary filtration, reverse osmosis is most commonly utilized to begin removing salt particles. Reverse osmosis is a process that purifies water by means of a semipermeable membrane that removes minerals (salt, in desalination’s case) and other particles. Reverse osmosis is an integral aspect of the desalination process. Once the reverse osmosis has been completed, the water is put through a final treatment, wherein chlorine and other minerals are added into the water for storage and safety reasons. Water from the plants is tested, and meets or exceeds all regulatory standards from drinking water. Desalination relies on simple science in order to take non-potable sea water, and convert it into safe, potable water for many people.
On the Carlsbad, CA coastline, there is a new asset that has been in the works for many years. Dating back to the early 1990’s, the County of San Diego discussed the possibility of installing a desalination plant along the San Diego coastline. Politics, drought, and funding issues caused a delay in the project, and the project was finally completed in late 2015. The project is reported to have costed upwards of $1 billion. The project was not wholly funded by local or state water agencies; in fact, a third party called “Poseidon Water” was privately funded to get the job done, and has developed what they call a “Public-Private Partnership Approach”, wherein “all parties receive project benefits commensurate with the risk of their project contribution. The author interprets this to mean that they have the capital to fund the project, and are in a position to allow the county/state/local authorities pay back any monies over an extended period of time. The Carlsbad Desalination plant is expected to produce 50 million gallons of water per day, which meets roughly 7% of the San Diego region’s potable water needs (Carlsbad Desalination Project, No Date).
Desalination at its face is a simple, effective manner of sourcing water for consumption. Considering the historic and long standing water supply issue that the state of California has faced throughout its history, the need for multiple water sources is crucial. The process seems to be fairly straightforward, and converts a naturally occurring substance (seawater) into a substance for which there is a high demand and low supply (potable water in California.) Barring the high costs, the process seems to have no real drawbacks. Unless, however, you happen to opine that the brine that is leftover post-reverse osmosis can damage sea life when it gets pumped back into the ocean. Many of the delays that the Carlsbad plant faced were a result of fear of negative environmental impact. Many opponents of the project believed, and likely still believe, that the brine created through reverse osmosis would change the levels of naturally occurring minerals once it was pumped back into the ocean. To be clear: reverse osmosis removes the minerals and salts from the sea water, resulting in clean and potable water. What, then, does the plant do with those minerals that were extracted? “If a plant is close to the ocean, the brine can be safely released back into the sea if it’s dissolved beforehand.“ (Than, 2011) Put simply: the plant returns the “brine” or “sludge” back into the ocean. The “sludge” is diluted, but there remains some factor of unknown as to what the long term effects of this imbalance of ocean mineral levels. As with most any process, there are always perks and drawbacks. “Marine life can be significantly impacted by discharge of the saline brine and other by-products produced by desalination, and; local seafloor habitat may be significantly altered by construction of intake and outfall structures.” (MBNMS, 2014) The potentially negative impacts that a desalination plant has leaves us with one question: Is it worth it?
While time may be the only true way to know for certain the answer of that question, one must weigh the needs of a community. Desalination is important to this author, as both an employee of a Southern California water agency, and as a resident of this state. The benefits and drawbacks of desalination remain to be seen. California, our nation’s “salad bowl” needs desperately to find a new water source. It is the opinion of this author that there is not a singular source. Desalination, rain water collection, new and improved catchment systems, and recycled water are all equally important facets of a viable water source solution for the state of California.