The most comprehensive commitment to water conservation in industrial manufacturing — every drop recovered, recycled, and reused. No liquid waste. Ever.
100%
Water Recovery
95+
Projects Delivered
Zero
Liquid Discharge
Our Position
HPT advocates Zero Liquid Discharge across every industry we serve. ZLD is not just regulatory compliance — it is the right engineering response to a water-stressed world.
We were among the first companies in India to champion ZLD as a standard, not an exception. Today, our integrated ZLD systems help industries achieve complete wastewater recycle — eliminating discharge liabilities and turning wastewater into a resource.
Definition
Zero Liquid Discharge is a water management strategy in which all wastewater generated within an industrial facility is treated and recovered — leaving no liquid effluent for discharge to the environment.
The recovered water is recycled back into the process, and the residual solids are removed as a dry cake or crystallised salt for safe disposal or reuse.
A ZLD system integrates multiple treatment technologies — biological treatment, membrane concentration, evaporation, and crystallisation — into a single engineered system. The result is 95–100% water recovery and full compliance with even the most stringent regulatory requirements, including CPCB ZLD mandates for water-intensive sectors like textiles, tanneries, and distilleries.
System Reference
3 MLD Integrated ZLD — Textile Cluster, Tiruppur
How It Works
Biological and chemical treatment reduces BOD, COD, TSS, and suspended solids. Prepares effluent for membrane concentration — ETP output quality directly determines RO performance and membrane life.
Membrane concentration recovers 60–75% of water from pre-treated effluent. Concentrate stream — now at elevated TDS — forwarded to secondary concentration.
High-pressure RO further concentrates the primary RO reject, recovering additional water and increasing dissolved solids concentration to 40,000–80,000 ppm for evaporator feed.
Mechanical Vapour Recompression (MVR) or Multiple Effect Evaporation (MEE) evaporates water from the brine concentrate. Vapour reuse achieves high thermal efficiency — condensate recovered as process-grade water.
Crystallisers precipitate dissolved salts from concentrated brine as dry, handleable solids — NaCl, Na₂SO₄, or mixed salts — for collection and safe disposal or commercial reuse.
Vapour condensate from the evaporation stage is recovered as high-purity water — typically < 50 ppm TDS — and recycled directly to the process, completing the water loop.
Crystallised salt cake collected for safe disposal in lined disposal facilities or, where product purity permits, sold or reused (NaCl, Na₂SO₄ segregation possible with selective crystallisation).
Biological and chemical treatment reduces BOD, COD, TSS, and suspended solids. Prepares effluent for membrane concentration — ETP output quality directly determines RO performance and membrane life.
Membrane concentration recovers 60–75% of water from pre-treated effluent. Concentrate stream — now at elevated TDS — forwarded to secondary concentration.
High-pressure RO further concentrates the primary RO reject, recovering additional water and increasing dissolved solids concentration to 40,000–80,000 ppm for evaporator feed.
Mechanical Vapour Recompression (MVR) or Multiple Effect Evaporation (MEE) evaporates water from the brine concentrate. Vapour reuse achieves high thermal efficiency — condensate recovered as process-grade water.
Crystallisers precipitate dissolved salts from concentrated brine as dry, handleable solids — NaCl, Na₂SO₄, or mixed salts — for collection and safe disposal or commercial reuse.
Vapour condensate from the evaporation stage is recovered as high-purity water — typically < 50 ppm TDS — and recycled directly to the process, completing the water loop.
Crystallised salt cake collected for safe disposal in lined disposal facilities or, where product purity permits, sold or reused (NaCl, Na₂SO₄ segregation possible with selective crystallisation).
In Operation
MVR Evaporator — 1,500 m³/day ZLD System,
Maharashtra
Configurations
The right ZLD configuration depends on your effluent TDS, capacity, energy costs, and regulatory requirements. HPT designs each system for its specific operating context.
95%+ recovery
Most common ZLD configuration. Proven across textiles, tanneries, and chemicals. Multi-Effect Evaporator concentrates RO reject to near-saturation, producing evaporated condensate for reuse.
70–80% lower energy
MVR replaces steam-driven evaporation with mechanical vapour recompression — dramatically reducing operating energy cost. Preferred for large-capacity ZLD where energy OPEX is significant.
100% recovery
Complete zero discharge. Crystalliser converts brine to dry crystallised solids. Mandated for sectors with total discharge prohibition — textile dyeing in river basins, leather, distilleries.
What You Get
System designed to recover 95–100% of all water entering the ZLD loop, returning it to the process as reusable condensate.
Eliminates all liquid discharge liability. Meets CPCB ZLD mandates and NGT directives for water-intensive sectors.
Crystallised salts recovered as dry solids — Na₂SO₄ and NaCl streams can be segregated and reused or sold.
Recovered water replaces freshwater intake — reducing water purchase costs and groundwater dependency.
MVR and vapour recompression systems recover latent heat, dramatically reducing steam and electricity versus older technologies.
HPT designs the entire ZLD chain — ETP, RO, evaporation, crystallisation — as a single system with unified controls and one responsibility.
Applicability
Sectors under CPCB / NGT ZLD directive or operating near sensitive waterbodies
Sectors choosing ZLD for ESG, water security, and cost reduction
As water scarcity and ESG reporting pressures increase, ZLD is becoming a competitive advantage — not just a regulatory obligation. HPT supports both mandated and proactive ZLD implementations.
Our Advantage
Among the first companies to design and commission integrated ZLD systems in India — deep experience across every sector.
ETP + RO + Evaporation + Crystallisation under one contract, one responsibility — no gaps between technology providers.
Access to globally proven evaporator and crystalliser technologies through HPT's international technology alliances.
O&M services and long-term performance guarantees on ZLD systems — we don't hand over and walk away.
Our Methodology
ZLD design is a systems problem — not a sequence of independently specified equipment. A ZLD system is only as good as the integration between its stages.
If the ETP doesn't deliver the right quality to the RO, the RO doesn't deliver the right concentration to the evaporator, and the evaporator doesn't produce a brine clean enough for the crystalliser — the whole system underperforms.
HPT designs ZLD as an integrated system from the start. We model the full water and mass balance, specify each technology for the actual conditions it will see, and size each stage for the peak loads your process generates — not average conditions.
In Operation
Forced-Circulation Crystalliser — ZLD Plant, Gujarat
Specifications
Representative design parameters for HPT ZLD systems. All values are derived from full water and mass balance modelling specific to your effluent characterisation and operating conditions.
| Parameter | Typical Value | Notes |
|---|---|---|
| Capacity Range | 50 KLD – 5 MLD | Multi-train for larger flows |
| Water Recovery | 95 – 100% | System configuration dependent |
| Feed TDS Range | Up to 80,000 ppm (post-ETP) | Evaporator-stage dependent |
| Evaporation Technology | MEE / MVR | Energy and capacity dependent |
| Steam Consumption (MEE) | 0.25 – 0.35 kg steam/kg evap. | Effect number dependent |
| Power Consumption (MVR) | 8 – 15 kWh/m³ evaporation | Load dependent |
| Residue Form | Dry salt cake / crystallised solids | Crystalliser configuration |
ZLD Upstream Stages
ZLD is the final destination. These are the technologies that prepare your water to get there.
Industrial wastewater pre-treatment — the upstream stage that determines ZLD system performance.
High-rejection membrane systems for TDS reduction — the membrane concentration stage within the ZLD loop.
Pre-treatment for RO — protecting membranes from fouling and extending ZLD system life.