This article covers portable units used to produce fresh drinkable water from sea water, and from brackish well or river water, where salt needs to be removed by Desalination. Other impurities, including bacteria and viruses, are also generally removed.
"Portable" covers units that can be moved from place to place, from pocket size to truck size.
Pocket Size
| Area | Consumption USgal/person/day | Consumption litre/person/day | Desalinated Water Cost US$/person/day |
|---|---|---|---|
| USA | 100 | 380 | 0.29 |
| Europe | 50 | 190 | 0.14 |
| Africa | 15 | 60 | 0.05 |
| UN recommended minimum | 13 | 50 | 0.04 |
Portable desalination units (RO) is a water purification technology that uses a semipermeable membrane. This membrane technology is not properly a filtration method. In reverse osmosis, an applied pressure is used to overcome osmotic pressure, a colligative property, that is driven by chemical potential, a thermodynamic parameter. Reverse osmosis can remove many types of molecules and ions from solutions, and is used in both industrial processes and producing potable water. The result is the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be "selective", this membrane should not allow large molecules or ions through the pores (holes), but should allow smaller components of the solution (such as the solvent) to pass freely