This summer marked my fourth trip to the island of Aruba. It is a small island country, spanning only 69 square miles, yet it is densely populated and comprised of a rich blend of cultures. During numerous conversations with locals, an interesting fact was presented to me: Aruba is home to the second largest saltwater desalination plant in the world, and arguably the best drinking water. How does the small island-country operate these desalination plants, and what could it mean for drought-stricken areas?
Aruba has been desalinating its saltwater since 1903, and a rising population and booming tourism a century later has further increased the country’s need for freshwater. Because Aruba has no freshwater sources, it must desalinate the surrounding ocean to make it safe for drinking. Water-en Energiebedrijf Aruba, N.V (WEB) is the country’s water and power plant. WEB has produced Aruba’s water since 1932. Today, WEB serves over 100,000 residents and the daily water consumption on the island is approximately 38,000 metric tons.
In order to meet an increasing demand for freshwater, WEB uses a method of desalination referred to as Sea Water Reverse Osmosis (SWRO). SWRO is a desalination technology that uses electric pumps that generate high pressure and force saltwater through semi-permeable membranes. Through this process the water is changed from saltwater to drinking water, and it all happens on this tiny island. Until 2015, a combination of two different methods were used, Multi Stage Flash (MSF) Evaporation and Sea Water Reverse Osmosis (SWRO). However WEB has since switched the desalination systems completely to SWRO, which WEB claims is more efficient than MSF.
Distributing the desalinated water to approximately 40,000 homes and businesses requires innovation. The drinking water produced at WEB is pumped to six water storage tanks on the premises. Additionally there are seven other tanks located on the island, with a total capacity of 65,393 cubic meters. WEB uses gravitational force to deliver the water by placing the tanks on hilltops. Not only is this practice energy efficient; it also ensures stable pressure from the time the water leaves WEB to the time it arrives to the consumer.
Although 71% of the earth’s surface is covered by water, only 2.5% of that water is freshwater—and the vast majority of it is largely inaccessible due to its location in the polar icecaps. Finding new, low cost ways to overcome limited freshwater resources is becoming increasingly important in the face of climate change.
In recent years California has proposed opening fifteen desalination plants, while construction has begun on one with an expected opening in 2016. Critics of the plants most often cite cost and environmental danger as reasons for opposition. However with California’s drought crisis, the idea of turning to the ocean as a source of freshwater is becoming increasingly attractive to many. Could desalination be the future of drinking water not only for the United States, but for other countries bordered by oceans? Time will tell!