Case study of
#00059 Passive solar still (basin distillation) — the simplest, most durable, most area-hungry option
Las Salinas, Atacama Desert, Chile
#00052
Implementer
Charles (Carlos) Wilson, engineer
Timeline
Jan 1, 1872 – Dec 31, 1912
Location
Description
First large-scale solar desalination plant, built in the Atacama Desert to supply freshwater to a saltpeter/silver mining community and its draft animals using highly saline mine effluent (~140,000 ppm) as feed. The installation comprised 64 timber-and-glass basin stills covering ~4,450 m², producing ~20,000–23,000 L/day with no fuel and minimal maintenance. It operated for ~40 years until the mines were exhausted, and remained the largest installation of its kind for nearly a century.
Metrics
4Lessons learned
- Operated ~40 years with minimal upkeep using only timber, glass, and a black-lined basin — confirming that passive solar stills require no consumables and are repairable with local materials.
- At ~4,450 m² for ~20,000–23,000 L/day (~5 L/m²/day), area is the binding constraint; any successor technology must demonstrate output per m² well above this ceiling to justify added fabrication complexity.
- Feed-water salinity of ~140,000 ppm (mine effluent) was handled without pre-treatment, indicating that basin stills tolerate extreme feed salinity provided the basin is cleaned periodically.
Documented Jun 7, 2026