Leather & Tannery Industry

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Sustainable and safe treatment of wastewater from leather processing

Leather production and tanning generate wastewater containing chromium, sulfides, organic pollutants, dyes, and high salinity.
These effluents are highly loaded, variable in composition, and can cause severe environmental impact if not properly treated.

Deepflow provides complete and modular treatment systems combining chemical precipitation, biological treatment, membrane separation, and vacuum evaporation, ensuring safe disposal or internal water reuse.
For tanneries with large daily volumes of wastewater, our PFET polymer-film evaporators offer an ideal solution — highly efficient and corrosion-resistant, thanks to polymer heat exchangers that handle acidic and saline conditions without fouling.

Reliable solutions for chromium and sulfide removal

Our integrated approach allows selective removal of heavy metals and sulfides, recovering valuable components and reducing chemical consumption.
A two-step process combining neutralization + membrane or evaporation concentration achieves the best balance between performance and operating cost.

The distillate obtained from the evaporator can be reused in rinsing or washing stages, while the concentrated sludge is safely dewatered and dried using our RedGan system for cost-effective disposal.

Typical wastewater sources

Soaking and liming baths
Tanning and retanning wastewater (containing Cr³⁺ and sulfides)
Dyeing and finishing rinsing water
Degreasing and washing wastewater
High-salinity streams from drum cleaning or pickling

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Process flow

1. Equalization and buffering → homogenization of flow and pH

2. RaeX pretreatment → coagulation and separation of solids, oils, and heavy metals

3. Aevya or PFET evaporation system
• Aevya for concentrated streams
• PFET for high-volume, saline wastewater

4. Seltra membrane polishing → ultrafiltration and reverse osmosis

5. RedGan drying → sludge dewatering and drying

6. Water reuse → distillate recycled into rinsing or washing lines

Your advantages at a glance

Up to 95% reduction in wastewater and disposal costs
Effective removal of chromium and sulfides
PFET technology for large, saline, or corrosive wastewater streams
Distillate suitable for direct reuse in rinsing stages
Optional Super Duplex 2507 / Titanium Grade 2 materials
Compact, modular design for easy integration

Recommended products

DES – Single-effect, steam/waste heat
DEH – Single-effect, heat pump
DE2S – Multi-effect, steam/waste heat
DE2H – Multi-effect, heat pump
DEP – PFET polymer film evaporator
DJY – Chemical dosing skid
DPFR – Pipe flocculation reactor skid
DUF-Ultrafiltration (UF) systems
DRO-Reverse Osmosis (RO) systems

Q&A

Q

Can RaeX automatically adjust chemical dosing based on real-time water changes?

A

Yes. Advanced RaeX systems use pH, conductivity, and turbidity sensors with PLC control to adjust reagent dosing dynamically.

Q

How is clarification efficiency evaluated?

A

It is assessed through turbidity, total suspended solids (TSS), floc quality, and retention time — by comparing inlet and outlet performance.
Q

How should flocculant or reagent solutions be stored to maintain stability?

A

They should be kept in sealed containers, at stable temperature, away from light, and at consistent concentration to prevent degradation.

Q

How often should deep chemical cleaning be performed compared to routine CIP?

A

When standard CIP cannot restore performance or solids removal efficiency, a stronger chemical regeneration should be carried out.
Q

How should polymers be mixed to optimize particle binding?

A

Begin with vigorous mixing to disperse the polymer, followed by gentle agitation to promote floc growth — the “bridging” principle.

Q

How does temperature influence floc formation?

A

Higher temperature accelerates reaction kinetics but may reduce floc stability and adsorption performance.