Abstract

The aim of the research was the neutralisation of particularly environmentally nasty chromium-free tannery wastes by their use for gas making.

Methane fermentation of wastes with the addition of excessive sludge from municipal sewage has been carried out. It has been found that, more gas with a higher methane content is obtained from the fermentation of tannery wastes than from the fermentation of municipal sewage sludge. Gaseous efficiency of the fermentation of tannery wastes varies between 950 – 1120dm3 per 1kg of decomposed organic dry substance. Gas obtained from fermentation of these tannery wastes may contain over 70% of methane.

The biodegradability of chromium-free tannery wastes in the methane fermentation process may additionally be increased by means of thermal treatment applied before fermentation.