🌱 Recommendations for Tannery Solid By-Product Management (Review)
The following, updated guidelines reflect the most advanced tannery waste management technologies in use today, emphasising practical solutions over purely academic research. While the reuse of untanned solid waste is tightly regulated, the document provides valuable insights into the management of tannery by-products in a sustainable and safe manner.
🦠 Regulatory Distinction for Skins During Leather Processing
Once skins pass the liming stage, they are no longer considered animal by-products due to:
- 🧪 Chemical Transformation: Skins undergo significant changes, making them intermediate products, not raw animal by-products.
- 🛡️ Regulatory Reclassification: Skins are reclassified post-liming due to pathogen reduction.
- 💰 Economic Value: Limed skins are processed into high-value leather, shifting them from waste to industrial material.
- 🌍 Environmental Protection: The removal of hair, fat, and other components significantly reduces health and environmental risks.
🛠️ Tannery By-Product Management Strategies
1. Dusted Salt
♻️ Reused after dissolution, clarification, or filtration for pickling.
🌟 Alternative Uses:
- Foundry casting
- Hypochlorite production
- Road de-icing
2. Green Fleshings
🔄 Recycled in rendering plants for tallow and meat meal recovery.
💡 Produces higher quality tallow with better recovery rates than limed fleshings.
3. Trimmings
🏭 Can be repurposed in tallow or gelatin production, depending on the liming process.
4. Limed Fleshings
4.1 Methane Production
⚡ Used in biogas production, when combined with farm, domestic, or fish waste.
🌍 Industrial-scale operations in Denmark, Sweden, and India are proving successful.
🔑 Requires ≥70% organic content for efficient anaerobic digestion.
4.2 Grease & Protein Recovery
🔬 Hydrolysis methods (acid/alkali or enzymatic digestion) recover valuable grease and proteins.
⚠️ Sulphide removal is essential to prevent hazardous emissions.
💨 Gas management through scrubber systems or boiler exhaust integration.
4.3 Composting
🌾 Mixed with bulking agents for organic composting applications.
5. Recovered Hair
💇♀️ Used in:
- Felt production
- Keratin hydrolysate for cosmetics and pharmaceuticals
- Slow-release fertilizers
💪 Pig hair is valuable for brush and consumer product manufacturing.
6. Limed Splits
6.1 Gelatin Production
🍽️ Extracted via lime hydrolysis for use in the food, pharmaceutical, and photographic industries.
6.2 Collagen Hydrolysate
🥩 Used as a food additive.
6.3 Sausage Casings
🔒 Strict chemical restrictions ensure compliance in manufacturing.
6.4 Pet Chews
🐕 Limed splits are dried and molded into various pet chew shapes.
6.5 Composting
🌱 High nitrogen and low carbon content enhance the decomposition process.
7. Grease from Degreasing Process
💧 Recycled into fatliquor production via sulphitation.
8. White Splittings
🍽️ Can be used for gelatin or collagen production. Use in food products is restricted.
9. White Shavings
🌾 Suitable for:
- Fertilizer production
- Collagen hydrolysate production
⚖️ Aluminum-containing shavings are applied to non-acidic agricultural land (subject to regulations).
10. Blue Splits and Shavings
10.1 Leatherboard Manufacture
📦 Chrome and vegetable splits are processed into composite leatherboard materials.
10.2 Chemical Hydrolysis
🧬 Used for industrial gelatin production.
Post Comment