When the time comes to kick back and relax, my wife and I enjoy vacationing in Aruba. Located in the southern Caribbean about 15 miles off the coast of Venezuela, this tiny (75 square miles) desert island has a lot going for it, starting with the climate. Being situated outside of the Caribbean’s notorious hurricane belt, the weather is monotonously the same every day – sunny, with an average temperature of 80 – 85 degrees Fahrenheit and a nice, cooling breeze provided by the constant trade winds that blow across the island. In the last 50 years Aruba has grown from being a sleepy little island whose main source of income was oil refining to a world-class resort destination whose main source of income is tourism.
As one might expect on a desert island, fresh water is scarce. Rainfall averages less than 20 inches per year, which may be ideal for sun worshippers but it’s not real conducive to human survival. Or tourism. For one thing, it’s kind of hard to make those fruity, umbrella-topped rum drinks tourists like so much without fresh water. So Aruba solved the problem by building one of the largest water desalination plants in the world. Water-en Energiebedrijf Aruba N.V., as the plant is officially known – or WEB for short – currently sucks up sea water and converts it into roughly 9.8 million gallons of fresh water per day using a multi-stage flash (MSF) distillation system. From what I’ve read, the plant produces some of the purest, highest quality drinking water in the world, and my taste buds would not disagree. The plant also doubles as the island’s source of electricity, cranking out somewhere in the area of 60 MW a day.
Considering the escalating need for, and diminishing supply of, clean drinking water in many parts of the world, the obvious question is, if a tiny island like Aruba can successfully convert enough seawater into fresh water to sustain its 100,000 inhabitants and more than 700,000 tourists who visit each year, why can’t other countries? God knows there’s enough seawater in the world, and we obviously have the technology.
Unfortunately, the solution isn’t quite as simple as it sounds. Water desalination, it seems, is a very energy-intensive, expensive process. Most estimates put the average cost to produce 1 acre-foot (approx. 325,851 gallons) of desalinated water at anywhere from $800 to $1400. And that’s not counting the cost to build and maintain the plant and infrastructure. Some of the countries who need fresh water the most also happen to be some of the poorest countries on Earth.
Then there are the environmental impact considerations. Depending on the type of energy used to run the plant, greenhouse gas emissions or nuclear waste could be a problem. And what do you do with all that salt you remove from the water? Dumping it back into the ocean could raise local salt concentration levels, adversely affecting marine life.
None of these problems is insurmountable and, as they say, “necessity is the mother of invention.” What’s important is that we have the technology now to convert seawater into drinking water if we have to. The economics of doing so will work themselves out as the need increases. Just ask anyone serving fruity, umbrella-topped rum drinks to tourists in Aruba.