ZLD Systems for
Chemical & Specialty Industry
Chemical, dye, and specialty chemical plants generate highly variable effluent with dissolved salts, heavy metals, organic solvents, and TDS up to 1,50,000 mg/L. Rototech engineers forced circulation evaporation and ZLD systems that handle this complexity without scaling, fouling, or corrosion failures.
Chemical Effluent Challenges
Heavy Metals & Toxicity
Chromium, nickel, zinc, copper, and lead in concentrations of 50–5,000 mg/L demand specialised MOC and pre-treatment before any thermal process can safely operate.
Extreme pH & Corrosion
Acid (pH 1–3) and alkali (pH 11–13) streams from batch processes attack standard SS equipment. MOC selection — Duplex, Titanium, Hastelloy — is critical to plant longevity.
High TDS & Hard Scaling
TDS of 30,000–1,50,000 mg/L with calcium sulfate, silica, and carbonate scaling propensity demands forced circulation designs with anti-scaling provisions and CIP systems.
Engineered for Chemical Grade ZLD
Chemical effluent cannot be treated with a one-size-fits-all evaporator. Rototech performs a detailed feed characterisation — pH, TDS, hardness, scaling indices, solvent presence — before selecting equipment and MOC.
- Phase 1: pH equalisation, chemical precipitation to remove heavy metals below detection limits.
- Phase 2: Solvent stripping (if applicable) via Stripper Column to recover VOCs and reduce COD.
- Phase 3: Forced Circulation MVR or MEE for volume reduction — typically 85–95% recovery.
- Phase 4: ATFD for final drying of concentrated slurry to dry salt cake for landfill or recovery.
Core Technologies for Chemical Industry:
Chemical Industry ZLD Questions
Which evaporator suits chemical effluent with high TDS and scaling?
Forced Circulation Evaporators are the standard choice for TDS of 30,000–1,50,000 mg/L with scaling tendency. High-velocity slurry circulation prevents salt deposition on heating surfaces. Final drying uses ATFD to yield dry salt cake.
Can Rototech handle effluent containing chromium or nickel?
Yes. We design forced circulation MEE/MVR in corrosion-resistant MOC — SS316L, Duplex, Titanium, or Hastelloy — for streams with Cr, Ni, Cu, Zn. Chemical precipitation removes bulk metals before evaporation to prevent equipment damage.
How do you handle highly variable pH from batch chemical processes?
pH equalisation and automated neutralisation is designed as Stage 1. Buffer tanks with auto-dosing stabilise pH to 6–9 before feed enters the evaporator, protecting heat transfer surfaces and instrumentation from acid or alkali attack.
What water recovery percentage is achievable for chemical ZLD?
Rototech systems typically achieve 85–95% water recovery depending on feed TDS and scaling potential. The recovered condensate meets reuse standards for boiler feed, cooling tower, or process water, dramatically reducing freshwater intake costs.
Handle Your Toughest Chemical Effluent
Share your effluent characterisation data and Rototech will engineer a corrosion-proof, scale-resistant ZLD system with guaranteed performance for your plant.