Considerations for selection
In reverse osmosis concentrate and permeate from the given solution is separated by applying semipermeable membrane. Before you buy reverse osmosis system, you must bear following considerations in your mind:
Water Potability
If you are using reverse osmosis system, make sure that water is bacteriologically safe for human consumption. The water on which RO system is to be used should be disinfected or sterilized on a continuous basis.
If the water is unchlorinated then TFC membrane should be used because of its greater resistance to bacterial attack. In case water is chlorinated there are two options. You can use CTA membrane as it is not chlorine sensitive. One can also use TFC membrane which is sensitive to chlorine with the addition of a carbon pre filter depending on the water quality and quantity.
Required Quantity of Pure Water
Quantity of pure water required, decides the size of reverse osmosis system.
Adequate pretreatment of water
If contaminants like iron, manganese or hydrogen sulfide are present in the water, they must be adequately removed by pretreatment in accordance with membrane tolerances. The hardness of the feed water should be reduced to a maximum of 10 gpg in order to prevent premature fouling of the membrane.
TDS level (Total Dissolved Solids)
The TDS level of the drinking water should have a TDS of below 500.
Requirement of the booster pump
If the pressure of the incoming water is less than 50 psi a booster pump may be required for your system.