Reverse osmosis uses a semi-permeable membrane to remove minerals and dissolved solids from water. RO can normally be considered economically attractive on water chemistries with 250ppm ≤ TDS ≤ 2000ppm. Between 150 -250ppm TDS, local economical considerations and water chemistry will determine whether RO is a viable option. Normally on waters with TDS < 150ppm, ion exchange without RO is feasible for TDS reduction.
A single pass reverse osmosis system typically removes 97% of the total dissolved solids (TDS) and 95% of naturally occurring organics. The water recovery and average membrane flux usually ranges from 65 to 80% recovery and 14 to 18gfd respectively with both being dependent on the water chemistry.