Bubble skyscraper design aims to purify drinking water

From the 2010 eVolo Skyscraper Competition comes a design that uses "mangrove cities" to purify drinking water. Called the Freshwater Skyscraper, French designers have earned special mention in the competition for their creation, which looks to the untrained eye like a series of soap bubbles blown by a child stacked end-on-end.

Design principles surrounding the competition specify that the skyscraper is the primary type of building which can meet the needs of crowded inner cities. Working slightly outside that principle and focusing on the countryside for their imagined creation, designers targeted the one looming problem of the 21st Century: water. According to the World Water Council, more than one out of six people do not have access to safe drinking water.

Most of the water on earth is tied up in oceans, and desalination for use on crops or as drinking water is not yet economically viable. Of the balance, a meager three percent, two thirds is frozen as ice in glaciers and icebergs. The remaining one percent is all that keeps humanity from perishing, and much of this water (64 billion cubic meters, or 70 percent) is tied up in growing food crops.

The Freshwater Skyscraper will address the issue of increasing water scarcity through a process known as transpiration. Unlike desalination, a mechanical process, transpiration occurs when plants "sweat" clean water through their leaves. By planting the bubble-shaped tanks with mangroves - which readily take up brackish water and deliver it as clean water - designers anticipate collecting as much as 30,000 liters (almost 8,000 gallons) per each one-hectare (2.47-acre) tower. That is, the Freshwater Skyscraper will be able to irrigate a one-hectare field of tomatoes per day.

In seeking a site for their Freshwater Skyscraper, designers looked at Almeria Province in Spain, on the coast of the Mediterranean Sea - the location where most of the fruits and vegetables destined for European markets are grown. BD+C

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