Zero Liquid discharge refers to installation of facilities and system which will enable industrial effluent for absolute recycling of permeate and converting solute (dissolved organic and in-organic compounds/salts) into residue in the solid form by adopting method of concentration and thermal evaporation. ZLD will be recognized and certified based on two broad parameters that is, water consumption versus waste water re-used or recycled (permeate) and corresponding solids recovered (percent total dissolved / suspended solids in effluents).
The significant industrial sectors like Sugar, Distilleries, Tanneries, Pulp & Paper, Textile, Dyeing, and Dairy would need special emphasis for enforcement of ZLD. It is important to mention that in the name of ZLD, no forceful injection into ground water table is to be tried 3 nor utilizing effluents / permeate for irrigation / or horticulture. ZLD would strictly means recycling treated effluent back for re-use in industrial / or domestic purpose but, exclude use / disposed in ambient environment. ZLD is applicable to industries having high BOD and COD load, colour bearing effluents, having metals, pesticides and other toxic / hazardous constituents.