Reverse Osmosis – What is Reverse Osmosis – Page 2
As mentioned before Osmosis is the passage of water through a semi permeable membrane from a dilute solution to a concentrated solution is known as Osmosis.
Reverse Osmosis is the reverse of the above, but for water to travel in the opposite direction pressure is applied (see Osmotic Pressure).
Reverse Osmosis equipment will typically remove everything out of the water except the water itself.
Most Reverse Osmosis units now use spiral wound membranes, due to the manufacturing technology moving onward have now become the cheapest membranes on the market.
Usually an R/O system will be between 80-90% efficient only rejecting around 10% of the total incoming water to drain. The rejected water on an Reverse Osmosis unit is continually referred to as the concentrate whilst the quality water which has passed through the membrane is referred to as the permeate 100% conversion of feed water to permeate is referred to as full flow but usually as explain membrane technology can only provide us with partial conversion.
Optimisation of a Reverse Osmosis units requires us to maximise flux (flow through the membrane) minimise energy expenditure, minimising downtime for membrane cleaning and minimising membrane replacement.
The pressure required for s Reverse Osmosis membrane used on backwash water is usually around 20 bar.
The pressure required for a Reverse Osmosis membrane used for distillation can reach 80 bar. New membrane technology is reducing these pressures all the time done by the CAD packages provided by the membrane manufacture. As RO membranes differ slightly from each manufacture it is prudent to always use the correct CAD package for each system design.
Temperature of the feed water is another large factor in the sizing of RO equipment.
A small increase in temperature can have large benefits when it comes to membrane efficiency. To view the sizes of Reverse Osmosis equipment available from Derwent Water Services please view: hello
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