Zero Liquid Discharge (ZLD) in Pharma API Manufacturing

Zero Liquid Discharge (ZLD) has become a critical sustainability and compliance strategy for pharmaceutical API manufacturers. With increasing environmental regulations, rising wastewater treatment costs, and a global focus on responsible operations, ZLD helps API plants eliminate liquid effluent discharge while maximizing water recovery and minimizing ecological impact.

What Is Zero Liquid Discharge (ZLD)?

Zero Liquid Discharge is an advanced wastewater management approach that ensures:

• No liquid effluent is released into the environment
• Maximum water is recovered and reused within the facility
• All dissolved and suspended solids are converted to dry, manageable solids

This is achieved through a combination of physical, chemical, thermal, and membrane-based processes.

Why ZLD Is Critical for the Pharma API Industry

Pharmaceutical API operations generate complex wastewater streams containing:

• Organic solvents
• High TDS (Total Dissolved Solids)
• High COD/BOD
• Residual chemicals
• Salts, heavy metals, and process impurities

ZLD addresses these challenges by offering:

Environmental protection: No effluent discharge prevents contamination of surface water, soil, and groundwater.

Regulatory compliance: Countries like India, China, and the EU increasingly mandate ZLD or near‑ZLD for pharma and chemical plants.

Sustainable water management: Recovered water (often 90–95%) supports utilities like cooling towers, boilers, and cleaning operations.

Positive corporate sustainability image: Supports ESG goals and aligns with global green‑chemistry initiatives.

How ZLD Works: End‑to‑End Process Flow

A typical ZLD system for API manufacturing includes the following stages:

1. Primary Treatment

Removes bulk contaminants.

• pH correction
• Coagulation/flocculation
• Equalization tanks
• Oil/grease removal

Prepares wastewater for downstream processes.

2. Membrane Treatment (RO/UF/NF)

Ultra‑Filtration (UF)

Removes suspended solids, colloids, and biological matter.

Reverse Osmosis (RO/NF)

Produces:

• Permeate (clean water) → reused in utilities
• RO reject (concentrate) → sent to evaporator

Membrane systems significantly reduce load on thermal ZLD units.

3. Evaporation & Crystallization System

Multiple Effect Evaporator (MEE)

Uses steam to evaporate water from RO reject.

Agitated Thin Film Dryer (ATFD) or Crystallizer

Concentrated brine is dried to produce solid salts/crystals.

Outcome:

Clean distilled water + dry solids ready for safe disposal.

4. Condensate Polishing Unit (CPU)

Purifies distilled water from evaporators to remove:

• Low‑boiling organics
• Volatile impurities

This ensures condensate meets reuse quality standards.

5. Solid Waste Management

Final solids can be:

• Sent to a TSDF (Treatment, Storage & Disposal Facility)
• Recycled (where applicable)
• Stabilized and disposed responsibly

Benefits of ZLD in API Manufacturing

1. Water Recovery and Reuse

Up to 90–95% water is recovered, reducing fresh water dependency.

2. Protects Surrounding Ecosystems

No discharge ensures rivers, lakes, and groundwater remain unaffected.

3. High Operational Control

API facilities maintain tighter control over pollutants, COD/TDS loads, and variability.

4. Enhanced Reputation with Regulatory Bodies

Demonstrates proactive environmental responsibility.

5. Supports Sustainable and Cost‑Effective Manufacturing

Though capital-intensive initially, long-term operational savings and regulatory certainty make ZLD a strategic investment.

ZLD Challenges in Pharma and How They Are Addressed

▪ High variability in wastewater composition

Handled using segregation systems and multi-stage treatment.

▪ High operating costs

Reduced using:

• Heat recovery
• Energy-efficient MEEs
• RO/NF pre-concentration

▪ Fouling in membranes and evaporators

Controlled through chemical dosing, pre-treatment, and regular engineering inspections.

▪ Managing mixed solvent/chemical streams

Addressed via source segregation and dedicated processing lines.

Sustainability in Action at Dr. Reddy’s: ZLD, Water Stewardship & Circularity

At Dr. Reddy’s, sustainability is not just a commitment—it is how we operate. Our Chemical Technical Operations SEZ facility stands as a benchmark in environmental responsibility with a Zero Liquid Discharge (ZLD) system that ensures 100% of wastewater is recycled back into the process. Equally important, the facility achieves zero solid waste discharge to landfill, reinforcing our dedication to circular material flows and minimal environmental footprint.

Across our API network in India, we have implemented ZLD and advanced wastewater management systems to ensure 100% wastewater treatment and recycling. Complementing this, we execute targeted water conservation initiatives to mitigate water risks and reduce freshwater dependency in water-stressed regions. These actions have delivered measurable outcomes: a 28.45% reduction in water intensity, and progress toward our water positivity goal by 2025, with 78% of water neutrality already achieved.

This integrated approach—combining process engineering, best‑available abatement technologies, and resource efficiency—demonstrates how we are building a greener, cleaner future for pharmaceutical manufacturing. It reflects our vision to pair innovation with responsibility and operational excellence, delivering medicines that improve lives while protecting the planet.

Dr. Reddy’s ZLD & Water Stewardship:

• 100% wastewater recycled at the CTO SEZ facility via Zero Liquid Discharge (ZLD).
• Zero solid waste to landfill at the SEZ, advancing circular waste management.
• ZLD and wastewater management systems implemented across all API manufacturing facilities in India, ensuring comprehensive treatment and reuse.
• 28.45% reduction in water intensity, driving down freshwater consumption per unit output.
• 78% water neutrality achieved, on the pathway to water positivity by 2025.
• Focused conservation initiatives to address water security risks in API manufacturing.

The Future of ZLD in Pharma API

API manufacturers are moving toward:

• Low-solvent and green-chemistry processes
• Hybrid ZLD systems (RO + MEE + Mechanical Vapor Recompression)
• Zero Freshwater Usage models
• AI‑based monitoring for predictive maintenance
• Closed-loop recycling plants

ZLD is evolving from a compliance requirement to a strategic sustainability driver.

Zero Liquid Discharge (ZLD) in pharmaceutical API plants ensures no liquid effluent is released into the environment. Through pre-treatment, membrane filtration, evaporation, crystallization, and water recovery systems, ZLD converts all wastewater into reusable water and dry solids. It enhances sustainability, regulatory compliance, and operational efficiency while protecting ecosystems and aligning with global ESG goals.