Pure Water - From Solar Energy
Solar distillation is a well known technology. The first known use of stills dates back to 1551 when they were used by Arab alchemists. Other scientists and naturalists used stills over the coming centuries including Della Porta (1589), Lavoisier (1862), and Mauchot (1869).
The first "conventional" solar still plant was built in 1872 by the Swedish engineer Charles Wilson in the mining community of Las Salinas in what is today northern Chile (Region II). This still was a large basin-type still used for supplying fresh water using brackish feedwater to a nitrate mining community. The plant used wooden bays (1.14 m by 61.0 m) which had blackened bottoms using logwood dye and alum. The total area of the distillation plant was 4,700 square meters. On a typical summer day this plant produced 4.9 kg of distilled water per square meter of still surface, or more than 23,000 liters per day (>6,000 gallons per day) (Harding, 1883). This plant was in operation until 1912. Even today one can find thousands of shards of glass and chunks of accumulated salt at this historical solar site.