Reverse Osmosis and How It Works

Reverse Osmosis (RO) was developed as a method of desalinating sea water and is the process where water is forced under pressure through a semi permeable membrane; the small water molecules pass through the pores to the product side and the larger dissolved solids are retained in the waste stream and flow to drain.

RO water is used for many applications e.g. in pharmaceuticals and window cleaning. Uni-Flo continues to supply this bespoke equipment into these Commercial and Industrial areas besides many others including Aquariums, Offices and Homes throughout the UK and overseas.

Membranes are available in different sizes for processing different quantities of water. Typically for residential systems, as small as 2" diameter and 10" long, while one for industrial use, like our Desalination plants in Gibraltar, utilise 8" diameter and 40" long membranes.

As pressure must be applied to the membrane surface in order to produce water, it has to be contained in a membrane housing. It is this pressure that supplies the energy to force the water through the membrane, separating it from unwanted substances. The solids left behind in the waste stream are automatically diverted to a drain so they don't build up in the system as with conventional filtering devices. This is accomplished by using a part of the feed water to carry away the rejected substances to the drain, thus keeping the membrane clean. All RO systems are rated by their flow rates. The effectiveness and productivity of RO systems increase with greater water pressure and temperature.

The actual flow rate of any reverse osmosis membrane depends on feed water pressure and temperature. Membranes are rated when the feed water datum point is 25 degrees C; the datum pressure is dependant on a number of things with the type of application being the main factor i.e. Sea, Brackish or Tap Water.

See the Filtration Spectrum

Marine desalination

We are Premier Dealers for suppliers of commercial and pleasure craft desalination systems.

Land desalination

In 2000 we commissioned two sea water desalination systems for The Municipal of Gibraltar. Each plant produces 1000 m3/day (1 Million litres/day) of drinking water.

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