Reverse osmosis is a filtration process where the flow of pretreated water passes tangentially with respect to the membrane surface, while the permeate is extracted perpendicularly the water is separated from its almost total dissolved mineral content which is continuously swept from the surface and goes to waste or is recirculated with the help of a high pressure pump .

This system is also called “crossflow filtration”, which is much more efficient than conventional filtration. This process allows the removal of dissolved salts, viruses and bacteria. Currently, there are different purity levels that vary according to the properties and composition of this substance; they are regulated by different standards that establish references according to their applications, among these are the American Society for Testing and Materials (ASTM), British Standards Institution (BSI) and the International Organization for Standardization (ISO).

Systems for the pretreatment of raw water

In this type of system, pre-treatment of the raw water is necessary for:

• Sediment control: if the mineral composition of the source water is high, it will be necessary to use a desander to separate sand and coarse suspended particles from the raw water. A water softener or water softener can also be used to reduce minerals such as calcium and magnesium.
• The dechlorination: an activated carbon filter sized at 3.7 gpm is usually employed, which is designed to meet the feed flow demand of the reverse osmosis system, whose feed flow rate must be higher than the permeate rate. The activated carbon also helps to decrease the organic loading of the flow.
• Scale control (scaling): as the water hardness is lowered, this treatment is commonly performed by traditional water softeners, whose configuration is a double alternating system.
• Biological control: usually performed with an ultraviolet (UV) sterilizer, which produces germicidal UV radiation.

Applications of the reverse osmosis process in water treatment

Reverse osmosis for water treatment is more common than it seems because it is an economical solution that requires little energy, which makes it an environmentally friendly solution. Its applications are diverse and range from industry, laboratories to stores and health centers, among which we can highlight:

• To obtain drinking water: it is commonly used for the desalination of seawater, this process usually surpasses in performance and effectiveness processes such as distillation, electrodialysis or ion exchange. It is often used on islands, ships, and has been widely implemented in the Middle East for water desalination. To be considered for use, it is important to consider the amount of salt in the water, since the osmotic pressure increases as the salinity increases. It is also used for the treatment of surface water. Hospitals, hotels and restaurants use this type of system for the purification of drinking water.
• In industry: it is applied in process lines since it makes it possible to recover most of the water at high purity for reuse. In addition, it has the advantage that waste treatment is less costly. It is most frequently used in the metallurgical industry, where surfaces require special high quality cleaning for welding and lacquering, in the pretreatment of boiler water, for wastewater purification, in the dairy industry and in the production of pharmaceuticals. In the agricultural industry for irrigation of crops with pond water. In the optical industry it is required for the production of anti-reflective or satin glass.

At KALSTEIN we have different purification systems that fit the user’s requirements. Our water treatment equipment has outstanding features such as simplicity and ease of installation, operation, and maintenance. In addition, it has an integrated control system to monitor water conductivity, a temperature compensation system and a leakage sensor. You can find more information about the different types of systems that Kalstein has to offer. Visit our catalog HERE. If you require information for PURCHASE or SALE contact us.