Advanced Effluent Treatment Solutions for the Tannery Industry
Turn chromium- and sulfide-rich wastewater into a circular-water asset with best-in-class treatment trains and Zero Liquid Discharge (ZLD) suites.
Critical Challenges in Tannery Wastewater
Highly variable pollutant mix – Cr³⁺, sulfides, proteins, fats, dyes, lime, salinity, high COD/BOD and strong odour.
Highly Variable Pollutant Mix
Cr³⁺, sulfides, proteins, fats, dyes, lime, salinity, high COD/BOD and strong odour create complex treatment challenges.
Tight Discharge Norms
Inland caps of COD ≤ 250 mg L⁻¹, BOD₅ ≤ 30 mg L⁻¹, Cr ≤ 2 mg L⁻¹, sulfide ≈ 0 mg L⁻¹, TDS ≤ 2,000 mg L⁻¹.
Occupational Hazards
Explosive H₂S evolves when alkaline beam-house liquors contact acidic chrome streams; rapid corrosion of metal and concrete.
Chrome-laden Sludge
Must pass TCLP or incur hazardous-waste levies, requiring specialized handling and disposal protocols.
Circular-economy Demands
Global brands audit water, salt and chrome loops (LWG, ZDHC, EU BREF) for sustainable operations.
WTT Integrated Treatment Line – Design Snapshot
Our comprehensive treatment train combines proven technologies with innovative process optimization to deliver guaranteed performance across all tannery applications.
| Process Stage | Core Design Feature | Operating Window | Guaranteed KPI |
|---|---|---|---|
| Rotary Brush Screener + Bar Rack | 6 mm bars → 0.5 mm wedge-wire drum, dual nylon brushes | 40 – 1,200 m³ h⁻¹ | ≥ 98% coarse removal; TSS ≤ 150 mg L⁻¹ to EQ |
| Equalisation & Catalytic Sulfide Oxidation | 24 h tank, fine-bubble diffuser grid, MnSO₄ 20 g m⁻³ | Mix power 50 W m⁻³ | Sulfide < 1 mg L⁻¹; pH 9.5-10 |
| Chrome Precipitation + Coag/Floc | Milk-of-lime, flash mix G≈900 s⁻¹ → slow mix 20 min; alum (70-120 g m⁻³) + polymer (1 g m⁻³) | pH 7.2 ± 0.1 | Cr³⁺ < 2 mg L⁻¹; TSS ↓ ≥ 65% |
| DAF / Lamella Settler | 45 µm micro-bubbles (12% recycle) or 55° PVC plates | ≤ 12 m³ m⁻² h⁻¹ | Oil < 5 mg L⁻¹; colour ↓ ≈ 40% |
| Hybrid Extended-Aeration (Oxic + Anoxic) | Step-feed, fine-bubble grid, DO cascade | MLSS 6-8 g L⁻¹; F/M 0.05-0.10 d⁻¹ | COD ↓ ≥ 92%; NH₄-N < 10 mg L⁻¹ |
| Secondary Clarifier | Circular, Thompson profile, half-bridge | Overflow 0.5 m³ m⁻² h⁻¹ | Effluent TSS < 30 mg L⁻¹; SVI < 100 mL g⁻¹ |
| Submerged Ceramic MBR | 0.05 µm alumina plates, air-lift scour 0.25 Nm³ m⁻² h⁻¹ | Flux 22-28 LMH @ 35 °C | Permeate SDI < 3; ≥ 4-log pathogen cut |
| High-Recovery RO | 3-stage array, NF pre-pass, isobaric ERD | Feed TDS 3-8 g L⁻¹; 85% recovery | Permeate ≤ 50 µS cm⁻¹ |
| Brine & Caustic Recovery | Softening → 2nd HR-RO → triple-effect NaOH evaporator | 15-20% of RO feed | NaOH reuse 55-60% |
| ZLD (MVC + Crystalliser) | ΔT 5 °C, latent-heat reuse ≥ 80% | SEC 10-12 kWh m⁻³ | Liquid purge < 0.5 m³ d⁻¹ (5,000 m³ d⁻¹ plant) |
| Sludge Dewatering | Belt press / decanter centrifuge, polymer 3 g kg⁻¹ DS | DS 30-40% | Chrome cake landfill-ready / kiln-co-firable |
Chrome Recovery Units (CRU)
98% BCS loop-back, pH 8.5, 90-min cycle with automated recovery systems.
40 m² skid treats 20 m³ d⁻¹
Submerged Ceramic MBR
0.05 µm alumina plates with pH 2-12 tolerance, steam-sterilisable to 350 °C.
Flux 22-28 LMH @ 35°C
High-Recovery RO
3-stage array, NF pre-pass, isobaric ERD achieving 85% recovery from high-TDS feeds.
Permeate ≤ 50 µS cm⁻¹
Zero Liquid Discharge (ZLD)
MVC + Crystalliser with ΔT 5 °C, latent-heat reuse ≥ 80% for complete resource recovery.
SEC 10-12 kWh m⁻³
Process Flow (Example 500 m³ d⁻¹ Plant)
Our integrated treatment train delivers 85-97% water recovery with solid salt cake production for complete resource recovery.
Primary Treatment
Biological Treatment
Advanced Treatment
Final Output
Why WTT Outperforms Conventional Plants
Our advanced technologies deliver superior performance across all key metrics, ensuring maximum return on investment and operational excellence.
| Metric | WTT | Legacy plants |
|---|---|---|
| Water reuse | 85-95% | 60-70% |
| Pretreat + RO energy | 0.5 kWh m⁻³ | 0.9 |
| ZLD energy | 10-12 kWh m⁻³ | 14-16 |
| Footprint | 0.12 m² m⁻³ d⁻¹ | 0.20 |
| Sludge yield | < 0.15 kg DS kg⁻¹ COD | 0.30 |
| Chrome recycle | 98% | < 10% |
| Start-up → compliance | 21 days | > 35 days |
| Remote diagnostics | Standard | Optional |
Chrome Recovery
98% BCS loop-back technology
95% Recovery
Patented single-skid HR-RO
Contractual Guarantees
Cr ≤ 2 mg L⁻¹, sulfide ≈ 0 mg L⁻¹
Closed Chemical Loop
LWG and ZDHC compliant
Specialised Tannery Services
Comprehensive solutions tailored for tannery industry requirements with guaranteed performance and operational excellence.
Chrome Recovery Units (CRU)
98% BCS loop-back, pH 8.5, 90-min cycle
Mn-Catalysed Sulfide-Oxidation
Auto-pH trim skids; alarms at 2 ppm H₂S
ISO-modular ETP blocks
100 m³ d⁻¹ up-gradable in 10% hot-swaps
Ceramic MBR
pH 2-12 tolerance, steam-sterilisable to 350 °C
NF-assisted HR-RO
22% lower osmotic load, inter-stage booster < 1.5 kWh m⁻³
Duplex-steel MVC
Vapour-recompression & condensate flash for 84% heat-reuse
IIoT O&M
AI aeration, predictive CIP, 48 h spares SLA
Detailed Frequently Asked Questions
Comprehensive answers to technical questions about our tannery wastewater treatment solutions.
Book a no-cost tannery effluent audit and receive a guaranteed-performance proposal within seven working days.
WTT – engineering certainty in compliance, cost and circularity for the global leather supply chain.