How we designed and commissioned a complete Zero Liquid Discharge system for a major textile mill in Punjab — achieving 97% water recovery and full PSPCB compliance while saving the client Rs. 45 lakh per year.
Project Overview
This case study documents the ZLD implementation for Vardhman Textiles Ltd, Ludhiana — one of India's largest composite textile manufacturers generating 500 KLD of highly coloured, high-TDS effluent from reactive and disperse dyeing processes.
The Challenge
- Highly variable effluent quality — BOD 400 to 1,200 mg/L, TDS 8,000 to 22,000 mg/L
- High colour from reactive dyes — 2,000 to 8,000 Hazen units
- Limited brownfield space for expansion
- 18-month aggressive PSPCB deadline
Our Solution (Phased Approach)
- Phase 1 — ETP Revamp: Retrofitted MBBR into existing aeration tanks plus ozonation for colour removal. BOD to below 30 mg/L achieved in 6 months.
- Phase 2 — UF and RO System: 500 KLD UF followed by 2-pass RO at 70% recovery. RO permeate recycled to dyeing; concentrate (150 KLD) fed to evaporator.
- Phase 3 — MVR Evaporator and Crystallizer: 150 KLD MVR evaporator. Crystalline sodium sulphate salt recovered at 4.5 TPD and sold to detergent manufacturers.
Results
| Metric | Before | After |
|---|---|---|
| Water Recovery | 0% | 97% |
| Outlet BOD | 900 mg/L | below 20 mg/L |
| Colour Removal | 30% | above 98% |
| Annual Cost Savings | — | Rs. 45 Lakh |
"AquaPure delivered the ZLD system on time despite the complex effluent. Their MBBR retrofit achieved compliance in just 6 months. Highly recommended." — Plant Manager, Vardhman Textiles