How Reverse Osmosis Systems Work
To understand how reverse osmosis systems can be used to turn brackish or sea water into potable water, it’s essential to understand how osmosis works. In layman’s terms, osmosis is a process whereby water flows from a diluted solution through a semi-permeable membrane to a higher concentrate solution. The membrane allows for extremely small particles to move from the one solution to the other.
In an osmosis system, a semi-permeable membrane is placed between two solutions allowing only specific particles to move through the membrane. The membrane in the case of sea water allows for instance, water through, but not the salt particles. Osmosis is a process whereby nature attempts to create a balance whereby the solution will have the same concentrate level on both sides of the semi-permeable membrane. In osmosis the pure water will thus move to the salt water compartment to create the equilibrium. Once the pressure is the same at both sides the equilibrium is reached.
With reverse osmosis systems pressure greater than the osmotic pressure is applied to the unit with for instance, a higher concentrate of salt. This allows for the process of osmosis to be reversed leading to a process whereby the higher salt concentrate solution’s water will move to the low pressure pure solution. With this process it’s possible to create pure water from sea water because the membrane used doesn’t allow salt particles through.
In summary then Reverse Osmosis or RO entails a process of applied pressure to the high concentration directing the water through a membrane. With this process even dissolved salts and dissolved organic substances can be removed from water to ensure a potable end product. Through RO we can thus produce ultra clean water and can take salt out of seawater.
Benefits of Reverse Osmosis
It is fast becoming a cost-effective method for getting clean drinking water. The method is also exceptionally energy efficient with low energy membranes being available in the market which contributes to cost savings regarding water treatment suitable for application in boiler feeds, drinking water treatment, and pharmaceutical applications.
No heat is applied and valuable dissolved materials can thus be recovered without causing destruction of material properties. Another benefit offered by reverse osmosis systems is that of being compact in design. With the compact designs space savings can be attained and plants can thus be installed even where limited space is available. It’s an uncomplicated process allowing for easy control and low maintenance.
How the membrane system works
The membrane is the essence of reverse osmosis filtering, but a second component is needed which is the processing pump. The pump is needed to apply pressure to the high concentrate solution to ensure that the water flows from the high concentrate to the low concentrate. To prevent the membrane from becoming clogged with impurities continues flow of water must be guaranteed and the pressure process pump is used to ensure this.
To increase surface area and reduce the space the membrane takes up, the membrane is usually in the form of a spiral allowing for water flow through the spiral channels in the element where the filtered water is collected in the centre part of the element. Membranes can consist of numerous spiral elements with several vessels connected within a single filtering unit. The filtered water that’s collected at the centre moves down to a holding or drain unit. Remaining water goes through more vessels until only the cleanest water remains in the holding tank.
We offer an extensive range of reverse osmosis units that can be used in a wide range of applications. We manufacture the RO units in Johannesburg and can ship as well as install and maintain the units at client premises. Clients also have the choice of customisable portable RO units according to their size requirements. With technical support available throughout the year, clients have the assurance of uninterrupted supply of clean water and very limited down time for plants. The systems available from us can be used to soften water, produce drinking water, desalination and also be applied in the food & dairy industries.
We furthermore stock superior membranes from companies such as Toray, Dow, Hydronautics and Vontron, known for their expertise in the manufacturing of water treatment membranes. Whether you require a small RO system or a custom built plant, contact us today to discuss your requirements.