Volume 87, 15 January 2015, Pages 874–881
Pollution reduction in an eco-friendly chrome-free tanning and evaluation of the biodegradation by composting of the tanned leather wastes
Highlights
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- Titanium tanned hides reached the quality standard values for leather.
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- Wastewaters from titanium tanning were less pollutant than the chrome tanning.
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- Composting of leather with food wastes is a promising alternative to landfills.
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- Size reduction near 50% was achieved with titanium tanned hide in composter.
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- No biodegradation was observed for chrome tanned hides.
Abstract
Chromium
is one of the most important environmental concerns related to
tanneries. The most often used process for hide tanning is chrome
tanning. This implies the presence of chromium both in wastewaters and
in leather wastes. Leather wastes have to be disposed in landfills what
entails a considerable environmental impact and high cost. In this work,
a study about the effect of a chrome-free tanning process using
titanium salts instead, on the wastewater and on the solid wastes has
been performed. In this way, a study of biodegradation of leather waste
samples tanned with different tanned agents by composting together with
food wastes is carried out in a laboratory composter. Results indicated
that leather tanned with titanium salts met the required quality
standards. Besides, the concentration of organic matter and salts in the
tannery process wastewater was lower comparing with the chromium
tanning agent. In the biodegradation study by composting, leather
samples tanned with titanium were degraded, reducing around 10% the
carbon content with the subsequent diminution of the C/N ratio. In
addition, the size was reduced 41% in 45 days. However, leather sample
tanned with oxazolidine was partially degraded in the composter;
meanwhile chrome and vegetable tanned leather kept inalterable.
Keywords
- Tanning process;
- Titanium;
- Leather;
- Biodegradation;
- Composting
- Corresponding author. Tel.:
+34 963876386; fax: +34 963877639.
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