Industrial RO ( Reverse osmosis ) works on the process just reverse of osmosis. So to understand reverse osmosis first we need to understand osmosis.
What is osmosis?
In simple terms ” Osmosis ” is a process in which a fluid moves from lower concentration to higher concentration through a semipermeable membrane.
In other words we can say that it is a process in which solvent moves across a semipermeable membrane separating two solutions of different concentration.
The semi-permeable membrane allows only solvent not solute.
What is reverse osmosis?
Reverse osmosis is a process which is just opposite of osmosis. In reverse osmosis the movement of fluid from higher concentration to lower concentration takes place .
The another difference is that osmosis can happens without applying pressure on any side of the semipermeable membrane but in reverse osmosis we have to apply the pressure in the “Mains Water” to get it passed through the membrane .
The extra solute particles are drained through reject line.
The reverse osmosis process is mainly used in wastewater treatment plants , recycling of water & desalination ( Removing extra salt ) of water. [source]
Working procedure of reverse osmosis Ro plant
The working principle of Industrial Reverse osmosis RO plant is based on the “reverse osmosis mechanism ” which is mentioned above.
Block diagram of Industrial reverse osmosis system
Explanation of Reverse osmosis block diagram
Raw water is untreated water which contains high amount of salts , Sediments , odour , bacteria & viruses. This water can be a ground water , well water or from any other source which contains high amount of salts & other contaminants .
Raw Water Pump
Raw water pump boosts the untreated raw water into the plant . It is a type of centrifugal pump which creates enough pressure in the input line so the that water can easily pass through the carbon & sediment filters.
High pressure sensor
High pressure sensor actively monitors the input raw water line for high pressure. If pressure of the line exceeds the defined threshold , it sends a stop signal to the microcontroller & halt all the operations of the machine to prevent failure due to high pressure.
Low pressure sensor
Low pressure sensor ensures that the input line have always minimum recommended pressure required by the machine for its nominal operation. If pressure drops below a defined value , It triggers the system to halt its operation. Because in low inlet pressure conditions there are chances that pumps may run dry.
Sediment filter is used to remove the coarse sediment particles in the water like fine gravels , dust particles etc. This filter contains layers of crushed fine rocks which blocks all the coarse matter from the water. These type of matters can reduce the pump & membrane life in long run.
Carbon filter contains gravels of activated carbon . This filter removes all the odour from the water & make it colourless. Carbon has a built in tendency of attracting contaminants towards itself. water after passing through the carbon filter becomes free from odour & color.
High Pressure Pump
High pressure pumps now creates very high pressure upto 20 KG/CM2 which is required to pass the water from the small micronic holes of the membrane . The pressure of high pressure pump is calibrated according to the membrane used in the plant.
This is the stage of purification where magic happens. Membrane separates the high salt concentration & low salt concentration water in different lines. A membrane is made up of micron filter layers wrapped up on each other . The pores of the membrane are less than <0.1 microns which blocks all the salt contaminants & fine matter.
Flow meter measure the output water flow from the membrane . Separate flow meters are equipped on the permeate & reject line . The flow meters are very important to measure the plant performance in running conditions.
Reject valve is used to control the reject flow of the water . Tightening it upto a certain level creates pressure in the membrane housing which forces the water to pass through the membrane pores & because of it filtered water gets out from the permeate line.
At this stage water is exposed to the ultraviolet light to kill the remaining germs & bacteria present in water if any, because UV light has the tendency to break the Virus at DNA level .
Product or permeate water is stored in a tank which can be used as per requirement.
Industrial Reverse Osmosis Plant Performance
The performance of Industrial Reverse osmosis system can be monitored by installing add on equipments which gives you the live parameters of the plant during runtime. In order to accurately measure the performance of an RO system you need the following operation parameters at a minimum:
- Feed pressure
- Permeate pressure
- Concentrate pressure
- Feed conductivity
- Permeate conductivity
- Feed flow
- Permeate flow