100% water recycling, at a fraction of the energy conventional evaporators demand.
Zero Liquid Discharge (ZLD) is a wastewater treatment standard under which all process wastewater is either recycled or evaporated, so nothing is released as liquid effluent. In India, ZLD is already mandatory for sugar, distillery, and ethanol plants — these industries must adopt it, and hold a Central Pollution Control Board (CPCB) certificate, to qualify for government financial assistance.
ZLD is not yet explicitly mandated for sectors such as paper and pulp, pharmaceuticals, petroleum, and petrochemicals, but Pollution Control Boards routinely impose it as a condition of the "Consent to Operate." Many of these industries have adopted it voluntarily to stay compliant.
Despite growing water scarcity and rising freshwater costs, wider adoption has been held back by one thing: energy. Conventional ZLD systems, built around Multiple Effect Evaporators (MEE) and Mechanical Vapour Compression (MVC), consume roughly 1070 kWTh per cubic metre of wastewater recycled, a cost few plants can absorb at scale.
At First ESCO, we've developed a proprietary solvent-based separation process that selectively draws water out of brine, no chemical reaction involved, just a controlled physical affinity that can be tuned and reversed. The solvent is fully recycled in a closed loop, making the process continuous and efficient.
The interactive below walks through the separation cycle at a conceptual level, showing how the system moves through its stages. Use the step rail or let it auto-advance.
Waste water carrying dissolved salts enters the first tower and blends with solvent still warm from recycling. Watch the badge climb as the heater brings the blend up toward the working temperature for this stage.
Hover or tap any vessel to read its role. Use the step rail to jump to a stage, or the controls to pause and change speed. Two steps run two flows at once — that's the plant operating continuously, not a simplification. The two temperature badges are live readouts, not fixed labels: watch them climb and ease rather than jump, since neither tower snaps straight to its operating point. The heat exchanger has no tank of its own, so it's drawn as a block that charges red with stored heat in step 3, holds that charge through step 4, then discharges it — cooling back down — as it preheats the returning solvent in step 5.
This technology offers substantial energy savings in several currently energy-intensive applications by drastically reducing specific energy consumption:
Optimal for the concentration of Black Liquor, recovering water at a fraction of conventional evaporator energy demand.
Ideal for the concentration of Spent Wash, helping distilleries meet mandatory CPCB ZLD requirements affordably.
Applicable to any process requiring the concentration of liquids — pharmaceuticals, petrochemicals, and beyond.
For process flow diagrams, mass and energy balances, and project economics, our presentation covers the SAB-ZLD system in depth.
First ESCO's presentation on the proprietary SAB-ZLD process
By adopting the First ESCO SAB-ZLD process, industries can drastically reduce specific energy consumption while fully complying with environmental regulations — and recycle 100% of their process water.