c. Reverse Osmosis (Figure 1-12). After filtration to remove the suspended solids, the feed water is further
processed by reverse osmosis. The feed water is pressurized and delivered to RO vessels containing RO elements. In
the RO elements, the feed water flows across sheets of membrane material. Some of the water passes through the
membrane sheets and is collected to become product water. Most of the dissolved solids (salts) are blocked from
passing through. Only 1/3 to 1/2 of the feed water passes through the membrane sheets to become product water.
The rest of the water containing most of the dissolved solids (salts), continues flowing past the membranes and exits the
RO vessels as waste water.
Figure 1-12. Reverse Osmosis Process