Abstract

The patented Silflo air flotation process has been operated successfully at several tanneries to purify tannery wastewater (mainly to remove suspended solids) but it does not remove dissolved inorganic salts. The next obvious step was to see whether this treated wastewater could be recycled back into all or some of the tanning operations in the interests of water conservation. Trials in the LIRI experimental tannery have shown that the crust leather produced with the Silflo liquor from two tanneries – where this was used in all operations from the pre-soak to retanning – was as good as the crust leather made with tap water. This will now require confirmation in large-scale tanning.