BWRO VS HERO VS SWRO
1. BWRO (BRACKISH WATER REVERSE OSMOSIS)
If the source of the water is underground wells and the same is treated with reverse osmosis membrane filtration, the process is known as brackish water reverse osmosis. The source of supply to the plant is known as raw water tank. Raw water is fed to system by filter feed backwash pumps and the same is passed through sand filter with minute pore size where in the impurities are trapped (fine solids and silt). Anti-scalants are also used in order to make the water fit for membrane filtration process. Cartridge filters are used to remove fine particles of about 1 micron size. High pressure pumps are used to generate required pressure for membrane filtration process.
The RO process here consists of two stages: first stage is of pressure vessels no. as 10 whilst in the second stage the pressure vessel number is reduced to 5. The recovery used for design purposes is 75%. Finally the RO permeate is collected in another tank.Before permeate storage tank RO permeate water is employed by post treatment. It is dosed with caustic soda in order to maintain pH to neutral and chlorination is useful for storage purpose.
2. HERO (HIGH EFFICIENCY REVERSE OSMOSIS)
As discussed above that BWRO plants have a recovery rate of around 75 per cents and the same values is used for design purposes as well but for HERO plant the recovery rate can go beyond 99 per cent. These are highly efficient reverse osmosis system with minimal cost.
HERO systems are known for no waste at all. There is no wastage of water in these systems as the storage tank water which is used for rinsing is again filtered and the same goes back to the storage tank. The system also ensures the safety of the membrane against clogging during low pressure times. The overall system rejects 99.99 % of the total dissolved solids in the water. Some of the particular features are also listed:
- Polypropylene cartridge.
- Automatic Shut off valve.
- Easy installation.
- Quick connect fittings etc.
3. SWRO (SALT WATER REVERSE OSMOSIS)
This is also known as industrial salt water reverse osmosis system. This system has a recovery rate less than HERO but way better than BWRO. The range is from 90-97%. If the SWRO has the second pass of raw water, the recovery can go up by 2 per cent. SWRO has gained its reputation in treating water, economic viability and total dissolved solids rejection etc.The process for SWRO systems is named “reverse osmosis” because it is the opposite of the natural osmotic process. In the seawater RO process which mirrors the standard industrial fresh water RO process, water from a solution with a low concentration of dissolved solids (TDS) travels through a membrane seeking to dilute a higher concentration solution. A seawater reverse osmosis system is induced by applying pressure with a pump to a solution with a high concentration of dissolved solids, causing water from the concentrated solution to pass through the membrane, which is called product or permeate water.