ZERO LIQUID DISCHARGE (ZLD)

Zero Discharge Systems incorporate the use of Reverse Osmosis System for final treatment to the treated wastewater. As rules for disposal of treated effluent is becoming more and more stringent, one of the urgent needs is to treat the effluent to such an extent so that it can be recycled and then reused back in process itself. The RO System involves the use of thin-film composite membranes which allow passage of only water along with sodium and chloride ions, rejecting all other ions, molecules etc. of size > 0.0001 Aim. The RO system gives two streams  one is Permeate which is very pure and can be reused back in process; the other is Reject which has to be suitably disposed either by Multiple Effect Evaporator System (MEE) or Solar Pond Evaporation (SEP). The distillate from MEE is recycled back to ETP and the salts are sent to landfill. This ensures a completely Zero-Discharge system in terms of water.