Desalination in the Caribbean
Islands have long relied on the process to supplement natural water supplies
More than 7,000 islands of the Caribbean Archipelago are scattered over a million-square-mile area between North and South America. Some smaller islands are naturally dry, but some volcanic islands — like Grenada and St. Lucia — are well forested and provide significant water catchment to support spring water and surface water. But, as populations, agriculture, and industry grow, desalination is becoming more attractive as a water source throughout the entire region.
Before the use of desalination began in the Caribbean, typical water sources included surface water, spring water, and groundwater, as well as rainwater, which is harvested on less-arid islands. In the absence of these sources, freshwater had to be barged in. Voyagers probably brought the first desalination to the region in the form of shipboard stills in the 1700s, and desalination stills were installed on Key West and the Dry Tortugas in the mid-1800s.
But desalination arrived in earnest in the form of Multi-Stage Flash Distillation (MSFD) starting in the late 1920s, with plants constructed on Curaçao, Aruba, and Antigua. Starting on Bermuda in the 1970s, Seawater Reverse Osmosis (SWRO) plants began to supersede the older MSFD plants.
On Grenada, SWRO plants that have been plagued with operational problems have been allowed to sit idle for months at a time. However, desalination and a corresponding level of commitment to infrastructure are much more important issues in countries with fewer natural water sources, such as the British Virgin Islands and the Bahamas. And, Trinidad and Tobago, where water scarcity was affecting both domestic consumers and industrial users, turned to desalination on a large scale with its plant on the Gulf of Paria.
Public Acceptance of Desalinated Water
Public acceptance of desalinated water is high in the region. In the Bahamas, it’s preferred over groundwater. When Barbados began to blend desalinated water with groundwater, taste complaints were noted, but the complaints subsided with education.
In Grenada, however, the public prefers to capture rainwater for drinking, using desalinated water for other purposes when natural sources are unavailable. On Carriacou and Petit Martinique, lack of a water grid, a culture of free rainwater harvesting, and a lack of public education on desalination has made it difficult to develop a market for desalinated water.
Drawbacks of Desalination
All countries studied have found negligible environmental impact from desalination. Elevated saline levels from desalination plant brine are not considered hazardous in the Caribbean where sea currents quickly disperse it.
The cost of energy to power desalination is a more pertinent issue in the Caribbean than in most regions since fuel for generating electricity must be imported at elevated cost. One exception is Trinidad and Tobago, which has offshore natural gas assets. But countries that rely on desalination have generally judged it to provide enough quality, quantity, and reliability to merit high energy costs.
Decentralized treatment sites small- or mid-scale infrastructure directly at the source of demand, a strategy ideally suited for the Caribbean. In a region where municipal water grids are scarce and population centers are dispersed over rugged territory, siting several smaller facilities at the point of need can save on pipelining and construction costs.
Smart Packaged desalination units are now available in standard shipping containers for easy delivery and plug-and-play installation. The mega-infrastructure of centralized treatment tends to disturb scenery important to tourism, but decentralized systems are small enough to be tucked away out of sight.
Decentralized systems can also reduce dependence on fuel imports. Linda Zupon of Fluence USA and a member of CaribDA, explained:
There are a lot of people working to provide the Caribbean with alternative methods of energy production that will utilize the resources that are already in place in the Islands such as the sun, wind, and ocean waves. Energy-efficient equipment pairs beautifully with these technologies.
Moving forward, with new technology available and demand increasing — particularly in the wake of recent hurricanes — the growth of desalination in the Caribbean is expected to accelerate in years to come.