It is known as hyper filtration / Desalination or Reverse osmosis. In the Process of desalination of water Reverse Osmosis membrane technology plays vital role. We, at “Aquatherm” offers Industrial Reverse Osmosis System with world’s best spirally wounded thin film composite membranes and FRP or stainless steel housing. Performance of any RO plants/ RO Systems depends on proper pretreatment, and hence we incorporate appropriate prefiltration with required chemical dosing in the system. The system could be manual or fully automatic with safety interlocks.
- A pre-validated & pre-tested skid mounted solution!
- Complies and supersedes latest US,European & Indian Pharma standards for purified water generation and distribution!
- Designed & manufactured as per Pharma Engg. and Industrial standards!
- CGMP & GAMP compliance!
- Standardized product-fast track delivery-reduced time & compliance cost!
- Hot water sanitary(>80ºC) fully automatic RO-EDI skid!
- All bought outs item from reputed suppliers across the globe!
- New instant hot water sanitizable EDI to reduce sanitization time by hours!
- Sanitary SS 316L RO pressure tubes with TC ends!
- SS –316L sanitary polished TC end piping and valves!
- Argon/Orbitally welded sanitary piping and valves.
- Variable frequency drive based SS 316 high pressure pump ensures optimized power and lowest operating cost!
- SS 316L feed buffer cum sanitization tank with inbuilt electric heater control for built in CIP cum hot water sanitization skid!
- Flow Range:100 LPH to 50,000 LPH
- Compact and modular RO blocks
- Easy installation, operation and servicing
- Specific selection possible from a wide range
- High level of plant automation
- Visual monitoring system (VMS) for ease of trouble-shooting
- Stainless steel multistage centrifugal pump; inline suction and delivery allows easy maintenance and access
- Online product water quality monitoring
- Membrane and pump protection features
- ‘RO Advantage’ enhanced through
- Minimum pipe length to reduce system resistance
- Easy servicing with QRC (Quick Release Coupling)
- Material of construction: CPVC/SS
Reverse osmosis (RO) is a filtration method that removes many types of large molecules and ions from solutions by applying pressure to the solution when it is on one side of a selective membrane. The result is that the solute is retained on the pressurized side of the membrane and the pure solvent is allowed to pass to the other side. To be “selective,” this membrane should not allow large molecules or ions through the pores (holes), but should allow smaller components of the solution (such as the solvent) to pass freely.
Reverse osmosis is most commonly known for its use in drinking water purification from seawater, removing the salt and other substances from the water molecules. This is the reverse of the normal osmosis process, in which the solvent naturally moves from an area of low solute concentration, through a membrane, to an area of high solute concentration. The movement of a pure solvent to equalize solute concentrations on each side of a membrane generates a pressure and this is the “osmotic pressure.” Applying an external pressure to reverse the natural flow of pure solvent, thus, is reverse osmosis.
The process is similar to membrane filtration. 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. Reverse osmosis, however, involves a diffusive mechanism so that separation efficiency is dependent on solute concentration, pressure, and water flux rate.
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 seawater, which has around 24 bar (350 psi) natural osmotic pressure that must be overcome. This process is best known for its use in desalination (removing the salt from sea water to get fresh water), but since the early 1970s it has also 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 semipermeable 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 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. Osmosis is an example of diffusion.
In reverse osmosis, in a similar setup as that in osmosis, pressure is applied to the compartment with high concentration. In this case, there are two forces influencing the movement of water: the pressure caused by the difference in solute concentration between the two compartments (the osmotic pressure) and the externally applied pressure.
Treatment Stages during Reverse Osmosis Process:
- Sedimentation : High molecular weight chemicals such as alum or polyelectrolyte is been dosed in the raw water to increase filtration efficiency
- Chlorination : Bleaching Powder or Sodium Hypochlorite solution is been dosed in the raw water to decrease the bacterial & Viral contamination
- Suspended Particle Filtration : Clarifier or Multigrade Sand filter is vital part during the pretreatment to remove or minimize the load of the suspended particles, dirt,mud etc. thus protecting the Micron cartridge filters and membranes.
- De-chlorination & De-colourisation : It is necessary to remove colour,odour and chlorine from the water and hence Activated Carbon filter is considered . In some cases Sodium meta bi-sulphite chemical is been dosed in the filtered water to ensure the water is free from dissolved chlorine thus protecting the Reverse Osmosis membranes from the possible damage !
- Scale Prevention : Ion exchange resin for softening of water plays key role to reduce the load of total hardness. The Calcium and magnesium salts is been removed and replaced with sodium salts by means of water softner. In some cases Antiscalent chemical is been dosed in the filtered water to ensure the water with lesser load of total hardness in the feed water , thus protecting the Reverse Osmosis membranes from the possible damage !
- Micron Filtration : Micron cartridges of different ratings is the vital part in the pretreatment which removes particle sizes upto 1micron to ensure efficient and safe operation of RO water plant.
Reverse Osmosis Treatment:
In the Process the pressure needed to push water through the membrane, even as the membrane rejects the passage of salt through it. Typical pressures for Raw / brackish water range from 8.0 to 26 bar. In the case of seawater, they range from 55 to 81.0 bar .This requires a large amount of energy. Hence High Pressure pumps are mandatory and considered to be heart of the system.
The membrane assembly consists of a pressure vessel with a membrane that allows feedwater to be pressed against it. The membrane must be strong enough to withstand whatever pressure is applied against it. RO membranes are made in a variety of configurations, with the two most common configurations being spiral-wound and hollow-fiber.Typically it rejects the salts upto 95-99% from the feed water.
Areas that have either no or limited surface water or groundwater may choose to desalinate seawater or brackish water to obtain drinking water. Reverse osmosis is the most common method of desalination, although 85 percent of desalinated water is produced in multistage flash plants. Large reverse osmosis and multistage flash desalination plants are used in the Middle East, especially Saudi Arabia. The energy requirements of the plants are large, but electricity can be produced relatively cheaply with the abundant oil reserves in the region. The desalination plants are often located adjacent to the power plants, which reduces energy losses in transmission and allows waste heat to be used in the desalination process of multistage flash plants, reducing the amount of energy needed to desalinate the water and providing cooling for the power plant.
Sea Water Reverse Osmosis (SWRO) is a reverse osmosis desalination membrane process that has been commercially used since the early 1970s. Its first practical use was demonstrated by Sidney Loeb and Srinivasa Sourirajan from UCLA in Coalinga, California. Because no heating or phase changes are needed, energy requirements are low in comparison to other processes of desalinaton, but are still much higher than those required for other forms of water supply (including reverse osmosis treatment of wastewater).
The typical single-pass SWRO system consists of the following components:
- High pressure pump
- Membrane assembly
- Remineralisation and pH adjustment
- Alarm/control panel
The membrane assembly consists of a pressure vessel with a membrane that allows feedwater to be pressed against it. The membrane must be strong enough to withstand whatever pressure is applied against it. RO membranes are made in a variety of configurations, with the two most common configurations being spiral-wound and hollow-fiber.