Aruba, a small Caribbean island nation located just north of Venezuela, faces a unique challenge regarding its water supply. The island’s arid climate and lack of substantial natural fresh water sources, such as rivers or significant underground aquifers, mean that rainfall alone cannot sustain its population and thriving tourism industry. To meet all residential and commercial needs, the island must rely completely on converting the abundant seawater into potable drinking water. This reliance has made Aruba a global leader in large-scale desalination technology.
The Necessity of Seawater Conversion
The geographical and climatic conditions of Aruba make desalination a mandatory practice rather than a choice. The island receives low average annual rainfall, which is quickly absorbed by the porous, volcanic geological structure, preventing the formation of large, sustainable surface reservoirs. Early inhabitants relied on limited wells and small rainwater collection cisterns, which were inadequate for any significant population growth or industrial activity.
The necessity became acutely clear with the establishment of large industries and the growth of tourism in the early 20th century. By the 1930s, the island began implementing its first large-scale desalination efforts to secure a reliable supply of processed and drinking water. This commitment ensured that the island’s development was not restricted by its natural scarcity of fresh water.
The Technology Behind Aruba’s Water Supply
Aruba’s long-standing solution for converting seawater has centered on thermal desalination, primarily through Multi-Stage Flash (MSF) Distillation. This method is a complex thermal process that produces highly pure water by replicating the natural hydrologic cycle on a massive industrial scale. The Balashi plant was historically one of the world’s largest facilities of its kind, demonstrating the scale required for the entire island’s consumption.
The MSF process begins by heating the incoming seawater, often using steam generated by the island’s co-located power plant (co-generation). This hot seawater is then pumped into a series of successive chambers, or stages, each operating at a progressively lower pressure. As the water enters each stage, the sudden drop in pressure causes a fraction of the water to instantly boil, or “flash,” into pure steam vapor.
The steam rises and is immediately condensed back into liquid fresh water upon contact with cooling tubes. The process is repeated across multiple stages, ensuring maximum efficiency as the concentrated brine moves through the system, creating distilled water at each depressurization point. The resulting pure condensate is collected, while the highly concentrated brine is returned to the ocean.
The island has also introduced Seawater Reverse Osmosis (SWRO) technology to meet increasing demand and improve efficiency. SWRO uses high pressure to force seawater through semi-permeable membranes, which physically filter out salt and other dissolved solids. This combination of thermal and membrane technology allows WEB Aruba, the island’s utility company, to maintain a robust and flexible water production capacity.
Post-Production: Ensuring Clean Water Delivery
The water produced by both MSF and SWRO is initially too pure and acidic for safe drinking or distribution. Distilled water lacks the naturally occurring minerals that provide taste and can aggressively corrode the distribution pipes. Therefore, a crucial post-production step is re-mineralization, where necessary salts and minerals are carefully added back.
The purified water is treated by passing it over beds of natural crushed coral or limestone, which dissolves and imparts calcium and magnesium into the water. This process stabilizes the water’s pH level, making it non-corrosive, and improves the taste profile to meet high international standards. After re-mineralization, the water is disinfected, often with chlorine or ultraviolet (UV) light, to ensure sanitation before it enters the distribution network.
Water- en Energiebedrijf Aruba (WEB Aruba) manages the final purification and distribution. The treated water is pumped to a network of strategic storage tanks, many located atop hills with elevations up to 110 meters above sea level. This placement allows for distribution via natural gravitational force, ensuring stable pressure and reliable delivery across the island’s extensive pipe system.