An engineered oceanfront
At the San Alfonso del Mar resort in Algarrobo, Chile, an artificial lagoon parallels the Pacific coastline. When it opened in December 2006, the Guinness Book of World Records certified it as the world's largest swimming pool by area. The lagoon measures 1,013 meters (3,323 feet) long and covers 8.2 hectares (20 acres). It holds 250 million liters (66 million US gallons) of seawater and reaches a maximum depth of 3.5 meters (11.5 feet).
The project was conceived by biochemist Fernando Fischmann, who wanted a solution to the region's cold and rough coastal waters, which are often closed to swimming. His company, Crystal Lagoons, developed the technology to create a safe and warm body of water for recreation. The water in the lagoon is heated by the sun to approximately 26°C (79°F), which can be nine degrees warmer than the adjacent ocean. The sheer scale of the lagoon allows for activities not possible in conventional pools, including kayaking, paddleboarding, and sailing small boats.
A technological solution for water purity
Maintaining the clarity of 250 million liters of water required a new approach to purification and filtration. Conventional systems, which filter the entire volume of water multiple times daily, would be economically and energetically unfeasible on this scale. The Crystal Lagoons system operates on a much more efficient model.
The patented technology employs a system of sensors that constantly monitor water quality. Instead of continuously circulating high levels of chemicals, the system uses algorithm-controlled pulses of microdoses of sanitizing additives, targeting only specific areas as needed. This method uses up to 100 times fewer chemicals than traditional pool treatment. For filtration, the technology applies ultrasonic waves that cause suspended particles to agglomerate and settle. A mobile, robotic suction device then cleans these particles from the bottom of the lagoon. This process means only a small fraction of the water is physically filtered, consuming just 2% of the energy used by conventional filtration systems.