Zero liquid discharge is deployed across multiple sectors driven by different regulatory, environmental, and operational imperatives. This page covers the principal applications and the engineering challenges specific to each.
The textile sector is the most significant ZLD market globally. CPCB mandates in India’s 17 critically polluted industrial clusters require zero effluent discharge from dyeing and printing units. Key challenges: reactive and disperse dyes raise colour and COD; salt (NaCl) used in dyeing at 50–100 g/L creates very high TDS feed; TDS varies widely with production schedule.
Flue gas desulphurisation (FGD) systems scrub SO&sub2; from coal and oil combustion with limestone slurry. The resulting FGD blowdown wastewater contains 20,000–60,000 mg/L TDS with high sulphate, chloride, selenium, mercury, and arsenic. The US EPA ELG rule (2020) and EU IED BAT Conclusions require near-zero liquid discharge from FGD systems.
Pharmaceutical manufacturing sites face dual ZLD drivers: API containment obligations (EMA, US FDA guidance) prevent discharge of trace pharmaceuticals; and several sites in water-stressed regions are required to achieve water neutrality. Active pharmaceutical ingredients (APIs) at ng/L to µg/L levels must be destroyed before any discharge.
Acid mine drainage (AMD) from sulphide ore oxidation contains sulphuric acid, high sulphate, iron, and heavy metals at TDS 2,000–30,000 mg/L. ZLD prevents discharge to sensitive catchments and recovers water for reuse in the process plant — critical for mines in arid locations. See our AMD treatment page.
For budgetary purposes only — actual costs depend heavily on feed composition, required solid purity, and integration with existing infrastructure.
| Flow / Scale | Pre-treatment + RO | Evaporation (MVR) | Crystalliser | Total ZLD Train |
|---|---|---|---|---|
| 100 m³/day | – | – | – | – |
| 500 m³/day | – | – | – | – |
| 2,000 m³/day | – | – | – | – |
Figures are indicative AACE Class 5 estimates (±50%). A full feasibility study including feed characterisation, technology selection, and mass balance is required before project commitment. Contact us to begin the process.
Full ZLD system architecture from pre-treatment through crystallisation.
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