Presently in the name of ZLD, what all industrial units or plants do is only increase the wastage thus putting in the WWTP discharge into unnecessary usage like sprinkling the WWTP outlet Water on roads, mining over burden (OB) or road side trees, horticultural usage or landscaping and so on. 

But wasting Water in such activities is not ZLD by any standards. 

The real purpose is to make it fit for reuse in the plant. 

Be it the wasteWater from smelter or ore beneficiation process, tailing dam, cooling tower or even RO reject.

why it isn't happening is only because, None of the existing prevalent technologies like E T P or S T P are capable of dealing with such huge variety of contaminants or neutralizing them to zero level, making water fit for reuse. There’s no single formula fitting all the scenarios.

This episode explains how is it done and how does Cownomics Technology comes to the rescue.