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| Typical Number in Hospital: 10 | Cost Bands: 3,4,5 | References: 3 |
Water will pass through a semipermeable membrane from the weaker solution to the stronger solution. If sufficient pressure is applied to the stronger solution (in excess of the osmotic pressure) water can be made to pass in the opposite direction. This is reverse osmosis.
The technique is used in industry for producing pure water and is of interest in the production of sterile water for medical work such as for solutions for irrigating the bladder, for dialysis, and potentially for intravenous fluids. The cost of pure sterile water produced by this method is cheaper than the alternatives which normally involve distillation and autoclaving. Equipment is already available to produce water for bladder irrigation, and for haemodialysis. Production of water for haemodialysis by reverse osmosis is desirable where the tap water used to make up the dialysate solution contains excessive amounts of aluminium compounds.
The equipment consists of filters, water softeners or de- ionizers, carbon filter, and a semipermeable membrane driven on the input side at a high pressure. The process may be supplemented by autoclaving, boiling or pasteurizing before use.
Content and Design Copyright 2000 Dr. Malcolm C Brown. See Title Page for more details