Reverse Osmosis~ Structure of Reverse Osmosis Membrane

Inside view of Reverse Osmosis Membrane

A typical cut out view of the membrane is shown on the left:(click to enlarge)

The diagram shows how modern reverse osmosis membrane is package into a space saving structure as compare with classical view of reverse osmosis structure. The membrane with very large surface area is seal on three sides and wrapped around a core that feeds the water into the membrane. The yellow color stream is the feed stream which actually feeds through one end of the membrane. The concentrate stream which is red actually exited the system at the opposite end of the inlet stream and has a flow restrictor to ensure that the water spend enough time inside the membrane structure while the flow ensure that majority of contaminants on the membrane surface can be flush out..  The blue color diluted stream or clean stream which is blue permeate through the membrane is collected at the core of the membrane and exit at the far end of the system.

With this simple standard structure and some variation, it is possible to cascade multiple number of membrane into a system to increase the treatment capacity with the only limit on the feed pressure availability to ensure that the water pressure across both ends exceed that of osmotic pressure for a particular membrane.