It's a solar thermal Multi-Effect-Distillation (MED) plant! I was part of a team that suggested using geothermal heat for desal with MED technology in Perth, W

It's a solar thermal Multi-Effect-Distillation (MED) plant! I was part of a team that suggested using geothermal heat for desal with MED technology in Perth, Western Australia a bit more than a decade ago! The advantage over work based (i.e. electrical/Reverse Osmosis) systems is that you do not lose heat via Carnot (or real world, for that matter) efficiency. You utilize more of the original heat, and via the multiple stages ("effects") you can re-use the latent heat of vaporization over and over. MEDs are really cool gizmos!