Reverse Osmosis

Reverse Osmosis (RO) is a commonly used technology, with CRS having designed and manufactured numerous skid mounted, containerised and permanent RO systems. These turnkey plants have been produced for a broad range of industrial and municipal applications across Australia.

Reverse Osmosis (RO) is a technique that uses a semipermeable membrane to separate constituents at the ionic level. It has the smallest pore size (0.1 nm) of the membrane family, allowing for the removal of up to 99.98% of the feed TDS to produce highly purified water for domestic and industrial applications.

Reverse Osmosis is commonly used for desalination of sea water and brackish water for potable use. It works on the principles of diffusion, rather than size exclusion found in the other membrane technologies. In RO, a pressure is applied to the feed entering the membranes to counteract the natural osmotic pressure, forcing out the solute (typically water) to the permeate side whilst retaining all other constituents on the concentrate side.

Pre-treatment systems are necessary for RO systems as they are susceptible to fouling. Typical pre-treatment systems include solids screening, cartridge filtration, followed by chemical dosing. The chemicals required depend on the quality of the feed water. Acids can be used to inhibit calcium carbonate scaling, biofouling inhibitors which prevent the formation of slime and antiscalants which inhibit all scales (sulphate, fluoride, phosphate and carbonate).

CIPs are also used in RO systems which involve chemical flushing and soaking to remove foulants and restore the majority of the membrane’s function.