Baihuipu Treats Tannery Wastewater for a Leather Cluster
Baiipu has treated tannery wastewater for a leather cluster in southern China, where the beamhouse and tanning streams carry sulphide, chromium and high protein COD that foul a single mixed plant. The split-stream train was commissioned in March and handles 100 m3/h across the cluster. The sulphide-bearing soak and liming water is oxidized separately, the chrome from tanning is recovered for reuse, and the combined stream then goes through biological treatment and coagulation, taking total chromium from around 80 mg/L to below 1.5 mg/L and COD from over 3,000 mg/L to under 150 mg/L. The cluster needed the chrome recovered rather than discharged, because the metal limit was the binding constraint on its operating licence.
Key Features and Benefits
Split the Streams Before Treating Them
Tannery water is really two problems: the beamhouse stream is high in sulphide and protein but low in metal, while the tanning stream is rich in chromium and low in the rest. Mixing them wastes reagent and complicates recovery, so the train collects them separately and treats each for what it actually contains. If your site also runs this kind of duty, Baihuipu Delivers Electroplating Heavy Metal Recovery covers the cost side of the decision in more depth. We set out the wider process route in leachate zero liquid discharge.
Separating the chrome stream is what makes recovery possible. Instead of precipitating valuable chromium to sludge, the tanning wash is concentrated and returned to the tanning process, which both meets the metal limit and cuts the client chemical bill. Where several streams need joint treatment, baihuipu commissions food wastewater anaerobic reactor is the more detailed reference.
Oxidize the Sulphide, Then Biologically Treat
The beamhouse stream carries sulphide that would poison biological treatment and stink on contact with acid, so it is oxidized to sulphate under controlled conditions before blending. Once the sulphide is gone, the high protein COD becomes biodegradable and the biological stage removes most of it. If your site also runs this kind of duty, baihuipu upgrades ro brine concentration membrane system covers the cost side of the decision in more depth.
The culture was selected to tolerate the residual tannins and the saline conditioning salts, which is what keeps the reactor stable through the daily hide-processing cycles. Anoxic and aerobic zones also handle the nitrogen from the protein load.
Coagulation for the Colloidal Tail
After biology a colloidal and coloured tail remains that the consent still exceeds, so a coagulation and flocculation stage strips it before discharge. The sludge is dewatered and managed as chromium-bearing waste where it contains recovered metal, keeping the metal out of the river.
The treated water meets the chrome and COD limits with margin, and the cluster meters the recovered chrome back into tanning so the loop is partly closed. Quarterly checks track the limits as the hide mix and processes change.
Technical Specifications
Tannery stream quality at key points of the split-stream train:
| Parameter | Raw Mixed Stream | Final Discharge |
|---|---|---|
| Total chromium | 40 to 90 mg/L | below 1.5 mg/L |
| Sulphide | high in beamhouse | oxidized to sulphate |
| COD | 2,500 to 4,000 mg/L | below 150 mg/L |
| Protein nitrogen | high | removed in biology |
| Design flow | as generated | 100 m3/h continuous |
Why Choose Baihuipu as Your Manufacturer
Choosing a manufacturer here comes down to one question: who is still accountable once the commissioning team flies home. Our answer is that we build and programme our own equipment, then stand behind it for the life of the plant.
Manufacturing Base in Guangdong
Owned production lines mean we control tolerances, materials and delivery. Standard modular units and bespoke skids are both built by our own people, so schedule commitments are ours to keep.
Two Decades of Field Data
Food and beverage, chemicals, electroplating, textile dyeing, mining, municipal work — we have commissioned across all of them. The useful part is not the project count, it is having seen how plants fail in year seven and designing those failures out.
Twenty-Plus Export Markets
We have shipped to the United States, Canada, Russia, Indonesia, India, Nigeria and Vietnam among others. Crating, export documentation and certificates are handled in-house, which keeps customs surprises to a minimum.
We Engineer the Whole Train
Screening, equalisation, biological or chemical treatment, membranes, evaporation, brine handling — the complete line comes from one organisation. Process design, mechanical, electrical and PLC programming sit under the same roof, so there is no gap for finger-pointing at handover.
Spare Parts and After-Sales Support
We carry membranes, pumps, blowers, diffusers and instruments for every system we supply. Remote support through the PLC is standard on most builds, and on-site service covers commissioning, training and urgent callouts.
Documentation You Can Actually Audit
Each system ships with as-built drawings, material certificates, welding records and a functional specification. If a client's own consultant wants to review the process calculation basis, we hand it over rather than treating it as proprietary.
Certification and Export Practice
CE marking is standard and we work to ISO 9001 procedures. Where a project calls for specific material grades, pressure vessel certification or ATEX-rated equipment, we build to that standard and ship the full documentation pack.
Let's Look at Your Numbers
Share your water analysis and site constraints and we will give you a straight assessment of the process route and the realistic operating cost before you commit to anything. Contact our engineers at WhatsApp: +86 13631765076, or find us at hkbhp.com.
WhatsApp: +86 13631765076
Customer FAQs
Why split tannery streams instead of treating them together?
The beamhouse stream is high in sulphide and protein but low in metal, while the tanning stream is chromium-rich. Treating them separately lets you oxidize the sulphide and recover the chrome instead of wasting reagent and precipitating valuable metal to sludge.
Can tannery chrome be recovered rather than discharged?
Yes. The tanning wash is concentrated and returned to the tanning process, which meets the metal limit and cuts chemical cost. Recovery is only practical when the chrome stream is collected separately from the rest.
What makes tannery wastewater toxic to biology?
Sulphide and residual chromium both inhibit biomass, and the high protein load swings the feed. Oxidizing the sulphide and splitting the chrome stream first is what protects the biological stage.
How is the chromium sludge handled?
Where the dewatered sludge contains recovered metal it is managed as chromium-bearing waste rather than ordinary sludge, keeping the metal out of the discharge and the river. The operating detail behind this sits in refractory wastewater biodegradability.
For adjacent technical angles, GaN Chip Wastewater Systems system and Baihuipu Commissions Condensate Polishing System system covers the same equipment from a different duty.
