Process for Reverse Osmosis Plant
- When a semi-permeable membrane separates two aqueous solutions of different concentrations, the solvent travels from the dilute solution to the concentrated solution. This phenomenon, called osmosis, continues till equilibrium is reached between the two solutions.
- In reverse osmosis, the flow of solvent (water) is reversed by application of external pressure to the concentrated solution (brackish or saline water). The water that passes through the membrane would be substantially free from the chemical impurities present in the brackish or saline water. The water that passes through the membrane is called permeate or product. The water that does not pass through the membrane and is continuously drained is called concentrate or reject. The ratio expressed as a percentage of product flow to the feed water flow is called the recovery.
- Since the membrane contains many fine pores, its performance is likely to deteriorate if these are blocked by suspended matter or scale forming salts of calcium or magnesium. This can be prevented by proper pretreatment of water before it enters the reverse osmosis unit.
