Zero Liquid Discharge (ZLD)
Zero Liquid Discharge (ZLD)
Zero Liquid Discharge (ZLD) is an advanced wastewater treatment technology designed to ensure no liquid effluent leaves your facility. At Purlieus Inc., we provide highly efficient and customized ZLD systems that help industries achieve 100% wastewater recycling, meet environmental regulations, and drastically reduce freshwater consumption.
What is Zero Liquid Discharge (ZLD)?
Zero Liquid Discharge (ZLD) is a treatment process where all wastewater is purified and recycled, leaving zero discharge to the environment. This technology uses a combination of evaporation, crystallization, filtration, RO membranes, and thermal systems to separate clean water from contaminants.
ZLD is essential for industries looking to:
Meet strict environmental or pollution control norms
Reduce dependency on freshwater sources
Recover reusable water from wastewater
Minimize ecological impact
How Our ZLD System Works
Our ZLD systems are engineered with high-performance components to maximize water recovery and reduce operating costs. The process typically includes:
1. Pre-Treatment
Removal of suspended solids, oils, grease, and organic pollutants
Equalization and chemical dosing to stabilize effluent quality
2. Membrane Treatment (RO/UF)
Reverse Osmosis (RO) to separate a major portion of clean water
Ultrafiltration for fine particle removal
Produces high-quality permeate for reuse
3. Evaporation System
Multi-Effect Evaporators (MEE) concentrate wastewater
Vapour Recompression Technology reduces energy consumption
4. Crystallizer
Further concentrates brine into solid crystals
Solids can be safely disposed or reused depending on composition
5. Water Recovery
Up to 95–99% water recovery
Treated water reused for cooling towers, process applications, or utility purposes
Key Features of Our ZLD Systems
100% wastewater recycling
Compliance with CPCB/SPCB norms
Energy-efficient evaporation technology
Fully automated (PLC/SCADA) controls
Low maintenance and long service life
Modular & scalable designs
Suitable for high TDS industries
Benefits of Zero Liquid Discharge
1. Complete Environmental Compliance
No liquid waste is discharged into land, water bodies, or municipal drains.
2. Maximum Water Recovery
Reduces dependence on groundwater and fresh water resources.
3. Significant Reduction in Waste Disposal
Only solid salts remain — reducing disposal costs and environmental risks.
4. Long-Term Cost Savings
Recycled water lowers operational costs in boiler feed, cooling, and processing.
5. Enhanced Sustainability Branding
ZLD helps your company demonstrate environmental responsibility and ESG compliance.
Frequently Asked Questions
Zero Liquid Discharge (ZLD) is an advanced wastewater management process in which no liquid waste is discharged into the environment. Instead, water is purified and recycled, and only solid residues (salts or sludge) remain. ZLD helps industries achieve environmental compliance and minimize water wastage
ZLD is important because it helps industries:
Meet strict CPCB/SPCB environmental norms
Reduce freshwater consumption
Prevent water pollution
Recover maximum usable water from wastewater
It is especially essential for industries with high TDS, chemicals, or hazardous effluents.
A typical ZLD system works through multiple treatment stages:
Primary & Secondary Treatment – Removal of solids, organic matter, and chemicals
RO (Reverse Osmosis) – Purifies water and separates high-TDS brine
Evaporators (MEE/TVR) – Concentrate the brine further
ATFD/Crystallizer – Converts leftover brine into solid salts
The process ensures zero liquid discharge and maximum water recovery.
ZLD is commonly required in:
Textile & dyeing units
Chemical & pharmaceutical plants
Power plants
Tanneries
Electroplating & metal finishing units
Food processing industries
Any industry producing high-salinity or toxic wastewater may be mandated to use ZLD.
Key benefits include:
100% elimination of liquid effluent discharge
Compliance with pollution control regulations
High water recovery for reuse in operations
Reduced dependency on freshwater sources
Safe disposal of solid residues
ZLD supports sustainability and reduces long-term operational risks.