A Glimpse into The Future of Water: Is Desalination a Real Solution?
On a recent trip to Indonesia, I visited the beautiful island of Gili Air. Upon turning on the faucet in our bungalow I noticed that the water smelled of sulfur and tasted slightly salty in the shower. After inquiring about the odd smell, the staff notified me that their water had been sourced from a desalination plant. I was pretty amazed to discover such a small island utilizing what I considered to be a seemingly complex technique to harvest water. I thought to myself, “Why can’t we do this in San Francisco where there is severe drought?” After all, it is crucial we consider our future relationship with water, recognizing increased drought conditions and water contamination as a threat to the delicate balance of our water system.
Desalination is the process of removing dissolved salts and impurities from seawater. In theory, desalination is logical way to provide an unending surplus of fresh water. Could it be the answer to our domestic water crises? Freshwater makes up roughly 2.5% of all the water on Earth. While the global demand for drinking water is going up, the ongoing deterioration of the oceans is also at all time high. The rate at which we consume water is anticipated to exceed the supply by 2030 which could theoretically put up to 45% of our projected GDP at risk (Moneywatch). If this is true, then future conflicts and wars could very well be fought over water, much like oil today. Low supply and high demand will in turn affect prices. Imagine a gallon of water costing the same as a gallon of gasoline today. If an impending water crisis is indeed on the horizon, then we will need to adopt better management practices of existing infrastructures as well as novel techniques for future freshwater extraction.
In Flint, Michigan property owners are continuously suing the EPA (Environmental Protection Agency) who they claim failed to “warn the community of the dangers of the toxic water” attributed to old lead pipes. This chilling tale serves as a stark reminder that it is critical to prevent future catastrophes caused by mismanagement of our water systems. According to the NRDC (Natural Resources Defense Council), 5,000 water systems in the United States are in direct violation of safe water guidelines. Jump over to the west coast to California who has experienced a five year drought. Despite the impending rain storms this winter, true recovery of natural waterways will take time. Water contamination is nothing new, and when you pair it with water scarcity and drought, it becomes clear that we are currently faced with some serious water issues in the U.S. So how can we properly manage and equip cities with healthy public water sources for generations to come?
To begin reflection on the future of water, we must ask ourselves, what are the main causes of water scarcity? What impact can economic water scarcity have on our lives? The consumption of water starts at the individual level and in the home. According to the EPA, the common U.S. household uses 400 gallons of water daily. So imagine all the water you consume during the day being poured in a giant bucket and then add to that bucket 10,000 gallons representing all the water each household loses to wastewater through inefficient infrastructures; toilets, using fresh water, leaks, century old pipes etc. We each carry with us a significantly large bucket that gets flushed away by a system that cannot not efficiently recapture this “runoff.”
Desalination appears to be an attractive solution to produce new freshwater. If the practice were to be paired with better wastewater management and capture, we could potentially save billions of gallons of water from flushing away annually. Utilizing this methodology, water can be delivered year round, even in times of drought. Desalination is typically regarded as a practice of exorbitant cost. Yet worldwide, desalination plants are employed in 120 countries. So despite some cost, why is the drought ridden West Coast not taking advantage of this technology? If a tiny island of only a few hundred inhabitants in Indonesia can pull off desalination, why can’t a city like San Francisco; one under extreme duress?
There are many environmental concerns surrounding the construction of new desalination plants. In modern plant design, when water is extracted from the ocean using large intakes, so is all the marine life in its path. The organisms subject to this entrainment often die due to high temperatures and high pressure. Larger organisms, such as fish, are subject to impingement when they become trapped against water intake screens. Additionally, desalination leaves an abundance of waste brine as a byproduct. The elevated salinity level brine produces can negatively impact water chemistry and the marine surrounding it. (Brett Koontz, DPA, REHS Thomas Hatfield, DrPH, REHS, DAAS California State University, Northridge.)
Although desalination technology is becoming more efficient, it is still an energy intensive practice. Take the Carlsbad Desalination Plant in San Diego for example, an engineering marvel that consumes nearly 40 megawatts of energy to produce 50 million gallons of potable water daily. That’s enough energy to power roughly 30,000 homes. For every two gallons of seawater that gets processed, roughly one gallon of potable drinking water is produced.
How do we address current desalination? Can future plants promote positive externalities for industries such as agriculture?
Promising extraction techniques can manifest if we carefully examine our existing water infrastructures, and design in tandem with the land. Imagine utilizing gravity feed piping wherever possible, allowing for more efficient systems that do not rely on heavy filtration and pumps; ultimately less energy intensive. The use of renewable energy sources to power these plants could support a more sustainable solution such as; solar, wind, or geothermal. If we build more efficient plumbing infrastructure in new construction, the leaky pipe dilemma will be eradicated, saving billions of gallons annually. And if we recapture gently used water from those systems, also known as greywater, we will not be so susceptible to “low water inventory.”
The byproducts of desalination can benefit other industries.
The captured waste brine from desalination plants can be repurposed for other industries such as agriculture. The nutrient buildup found in greywater sources can be beneficial to plants as a fertilizer to lawns. Brine water can be used to irrigate crops such as almond, pistachio, and olive. Furthermore, brine can be applied to aquaculture in harvesting spirulina and tilapia who thrive in high alkalinity and salinity conditions.
Imagine employing a credit reward system to businesses that save on water usage and recycle it for non-potable means. For example, a farmer could receive tax credits in exchange for employing a better drip irrigation system that saves on water usage and purchase recycled brine water as fertilizer. In this new system, “waste-water” has become a highly commoditized item which can be reused or sold for its high nutritional content. Using desalinated water, a grading system could be employed in which pure potable water comes at a higher price and graded greywater at another. A perfect example would be my shower in Indonesia that distributed “medium” grade, non-potable wash water.
Of course there will always be arguments to fault desalination, blaming its demise on high energy costs. But just like we can rethink any factory solution to make it sustainable, we can rethink desalination and our relationship with water. We can think in terms of it being a renewable source. Rethinking water usage begins with conservation and the monitoring of consumption at the individual level. Better management translates to monitoring water distribution at its source.
By looking at the big picture of our water loss, we can easily see the benefit to using smart water management technology.