Bencho Reverse Osmosis, Water Filters and Water Purification Systems
Reverse osmosis is similar to the membrane filtration treatment process. However there are key differences between reverse osmosis and filtration. The predominant removal mechanism in membrane filtration is straining, or size exclusion, so the process can theoretically achieve perfect exclusion of particles regardless of operational parameters such as influent pressure and concentration.
RO (Reverse Osmosis) however involves a diffusive mechanism so that separation efficiency is dependent on influent solute concentration, pressure and water flux rate [1] .It works by using pressure to force a solution through a membrane, retaining the solute on one side and allowing the pure solvent to pass to the other side. This is the reverse of the normal osmosis process, which is the natural movement of solvent from an area of low solute concentration, through a membrane, to an area of high solute concentration when no external pressure is applied.
Process
Formally, reverse osmosis is the process of forcing a solvent from a region of high solute concentration through a semi permeable membrane to a region of low solute concentration by applying a pressure in excess of the osmotic pressure.
The membranes used for reverse osmosis have a dense barrier layer in the polymer matrix where most separation occurs. In most cases the membrane is designed to allow only water to pass through this dense layer while preventing the passage of solutes (such as salt ions). This process requires that a high pressure be exerted on the high concentration side of the membrane, usually 2-17 bar (30 – 250 psi) for fresh and brackish water, and 40 – 70 bar (600 – 1000 psi) for sea water, which has around 24 bar (350 psi) natural osmotic pressure that must be overcome. The process is best known for its use in desalination (removing the salt from sea water to get fresh water), but since the early 1970’s it has been used to purify fresh water for medical, industrial, and domestic applications.
Osmosis describes how solvent moves between two solutions separated by a semi permeable membrane to reduce concentration differences between the solutions. When two solutions with different concentrations of a solute are mixed, the total amount of solutes in the two solutions will be equally distributed in the total amount of solvent from the two solutions. Instead of mixing the two solutions together, they can be put in two compartments where they are separated from each other by a semi permeable membrane. The semi permeable membrane does not allow the solutes to move from one compartment to the other, but allows the solvent to move. Since equilibrium cannot be achieved by the movement of solutes from the compartment with high solute concentration to the one with low solute concentration, it is instead achieved by the movement of the solvent from areas of low solute concentration to areas of high solute concentration. When the solvent moves away from low concentration areas, it causes these areas to become more concentrated. On the other side, when the solvent moves into the areas of high concentration, solute concentration will decrease. This process is termed osmosis. The tendency for solvent to flow through the membrane can be expressed as “osmotic pressure”, since it is analogous to flow caused by a pressure differential.
Standard Features
4” & 8” TFC spiral wound membranes
Epoxy painted steel frame
5 micron cartridge prefilter
PLC based control pane
Status lamps
Low pressure switch
Permeate & concentrate flow meters
Permeate conductivity monitor
FRP membrane housing
Stainless steel multi-stage pump with TEFC motor
Power supply : 460V/3Ph/60Hz
Programmable time delay and set points
115V/60Hz control voltage
High Pressure switch
Liquid filled pressure gauges, panel mount for pump suction, membrane feed, and final concentrate
R.O.Plants
We design and manufacture the Reverse Osmosis Plants according to the need for tap water, brackish water & sea water application. The production range starts from 100 LPH (Liter per hour) to 100 M3 per hour for 400 TDS to 45,000 TDS.