Zero Liquid Discharge: A Sustainable Solution

Zero Liquid Discharge (ZLD) is an advanced wastewater treatment process that ensures all wastewater is either recycled or evaporated, resulting in zero liquid waste discharge. The primary purpose of a ZLD system is to produce clean, reusable water. Industries adopt ZLD not only to reduce water costs through wastewater recycling but also to comply with environmental regulations set by pollution control authorities.

In India, ZLD is currently mandatory for sugar, distilleries, and ethanol manufacturing plants. In fact, to qualify for government financial assistance and incentives, these industries must adopt ZLD and obtain a certificate from the Central Pollution Control Board (CPCB). While ZLD is not explicitly mandated for industries such as paper and pulp, pharmaceuticals, petroleum, and petrochemicals under existing regulations, Pollution Control Authorities frequently impose ZLD as a condition for issuing "Consent to Operate." Consequently, many of these industries have voluntarily adopted ZLD to meet compliance requirements.

Despite the escalating scarcity and cost of fresh water, wider adoption of ZLD has been hindered by the high capital expenditure and significant operational costs associated with conventional ZLD systems, primarily due to their high energy demands. Typically, ZLD systems utilizing Multiple Effect Evaporators (MEE) and Mechanical Vapor Compression (MVC) evaporation systems consume approximately 1070 KW_Th per cubic meter (M³) of wastewater recycled.

First ESCO's Groundbreaking SAB-ZLD Technology

First ESCO, committed to energy and water conservation and environmental protection, has developed a groundbreaking technological solution to achieve ZLD with a significantly reduced specific energy requirement of just 33 KWth/M3. This drastically minimizes ZLD operating expenditure, paving the way for wider adoption of ZLD in industries and promoting 100% water recycling and conservation.

This innovative technology leverages the unique property of certain solvents to adsorb pure water when heated and desorb it when cooled. To learn more about the First ESCO SAB-ZLD (Solvent-based ZLD) system, please refer to our detailed presentation below.

First ESCO's presentation on proprietary SAB-ZLD Process

Furthermore, this technology offers substantial energy savings in several currently energy-intensive applications:

• Paper & Pulp Industry: For the concentration of Black Liquor
• Sugar / Ethanol Industry: For the concentration of Spent Wash
• Other Industries: For any process requiring concentration of liquids