Recycling in goat skin lime unhairing

• Type: Article in International Scientific Journal
• Date: 2011

Authors

Crispim, A (Author) Other; Sampaio, A (Author) Other; Nídia de Sá Caetano (Author) FEUP

Journal

Title: Journal of the Society of Leather Technologies and Chemists

Vol. 95

Pages: 59-62

ISSN: 0144-0322

Publisher: Society of Leather Technologists and Chemists

Indexing

Scopus - 0 Citations

Other information

Authenticus ID: P-00F-JAB

Abstract (EN): The environment is a factor of concern in our lives that forces society to search forand implement technologies that enable cleaner processes in industry. The leather industry is known to be a polluting activity that needs large amounts of water and, at the same time, produces a large flow of alkaline effluents rich in sulphide. The work in this study aims to minimize water and chemical consumption by recycling the liming bath used in goat skin unhairing. Two systems were tested for recycling of the liming bath from a hair-burning process (centrifugation and ultrafiltration) but for recycling the liming bath from a hair-saving process the only system tested was ultrafiltration. These recycling systems provided a good reduction in COD with better results when ultrafiltration was applied.The chemical reductions were 33% of sodium sulphide, 40% of anti-wrinkle and sodium sulphydrate and 25% lime for the hair-burning liming process with recycling. The chemical reductions were 32% sodium sulphide, 25% sodium sulphydrate and 25% lime, with an additional consumption of enzyme for the hair-saving liming process with recycling. A reduction in water used of 80% and 50% respectively in the hair-burning and hair-saving process was achieved. A brief economic analysis of the recycling systems used for the hair-burning process permitted us to conclude that both options are economically viable. The payback time in the recycling system using centrifugation is 3 years while for the recycling system with ultrafiltration the payback time is 4 years.

Language: English

Type (Professor's evaluation): Scientific