Softening With RO REJECT
Almost every industry uses soft water as process water for boiler, cooling water and other applications. Soft water is essentially non hardness water where calcium and magnesium is removed; thereby reducing scale formation on equipments. In general, soft
water is prepared after treating water with ion exchange resin; where calcium and magnesium ions are replaced with sodium ions. Resins are synthetic polymer based material cross linked with one or more polymers
having specific volume of ions for exchange. Once the water makes contact with with these resins, it will replace the calcium and magnesium ions with sodium ions thereby making soft water. Resins come with
definite capacity and will exhaust over a period of time when sodium ions are utilized. The entire resin bed needs to regenerate with sodium chloride solution for the next service cycle. A large quantity
of brine solution will be used for regenerating resin on daily basis. On a day-to day basis this process demands a considerable volume of brine solution.
Our system uses special ion exchange resin for water softening which can be regenerated by Reverse Osmosis (RO) reject water. The resin will be regenerated with RO reject water containing 0.5 % (5000ppm) or higher sodium chloride. Nearly all of brackish water RO system or desalination system pretty much have the same much value hence the system is viable. The resin is inert to other elements in RO reject; consequently it is trouble free and suitable for all categories of rejects.
- Eradicates the use of Sodium chloride solution. More economic and almost nil operation cost
- Disposal of RO reject made easy due to less TDS in reject
- Easily adoptable in existing system with minute modification
- Less operation cost
- Fully automatic and simple manual operation
- Less rinse volume water required
- Regenerated with 0.5 % (5000ppm) of salt
- Green technology
- High permeate recovery when used in RO pretreatment
- Increases membrane life and dosing when used in RO pretreatment
- Nil reactant amongst ions in reject. No setbacks
Calcium and magnesium are chief scaling elements in reverse osmosis treatment. Once their quantity exceeds the limit, pre treatment is indispensable to lessen hardness from water prior to membrane penetration. Also, membrane manufacturers recommend controlling the Langelier Saturation Index (LSI) of the water. LSI is the term used to express scaling potential of the feed water and LSI is to be maintained to a prescribed limit to shun fouling of membranes. An enhanced control on hardness is essential for membranes to give maximum recovery and life. Generally, ion exchange based system as pre –treatment is employed for softening the feed water as pretreatment to RO.