Dense and Porous Membranes
Reverse Osmosis membranes are usually split into 2 types; Dense and Porous. Porous membranes work like a sieve and are mainly ceramic giving a swing/surface filtration effect. The pore sizes range from 0.1 0.5 microns. Dense types are the polymetril cellulose acetate chemical diffusion type as usually used in a standard reverse osmosis unit. To increase the concentrate conversion rate, spiral wound reverse osmosis membranes it is possible to add more stages. Derwent Water Services can offer the above to all our customers because we manufacture our own equipment. Many of our competitors import cheaper non RO membrane life is usually incalcuable due to the many differing parameters on each application. The production rate of any membrane systems is always expressed on lts/hr.
How Do I Maintain My Reverse Osmosis Equipment
Reverse Osmosis units manufactured by Derwent Water Systemss require very little maintenance. Derwent Water Systems will offer safe training on our equipment or if preferred can provide a Service/Maintenance package.
Reverse Osmosis Membrane Cleaning
When cleaning fouled reverse osmosis membranes it is usually prudent to send one membrane to Derwent for diagnostics. This enables us to pre-determine the exact cause of fouling and to ensure steps are put into place to stop it happening again. Derwent Water Systems have the capabilities to diagnose all the major reverse osmosis membrane fouling agents. To clean the RO membranes usually the following applies.
|Diagnostic result||Removed by|
|Calcium carbonate fouling||Hydrochloric acid and citric acid|
|Metal oxide fouling||Citric acid and/or sodium|
|Calcium fouling or barium fouling||Citric acid or sodium EDTA pH 7-8|
|Organic fouling||Caustic, alkaline detergent enzyme detergent or hypochlorite|
|Biological fouling||Formaldihyde (hot) Sodium hypochlorite Hydrogen peroxide|
Derwent Water Systems have a range of membrane cleaning agents at the correct strength for cleaning the above reverse osmosis membranes. Please contact us for more information.