RECOVERY AND REUSE OF CHEMICALS IN UNHAIRING, DEGREASING AND CHROMIUMTANNING PROCESSES BY MEMBRANES

Membrane operations such as ultrafiltration, nanofiltration and revers e osmosis, properly integrated among them and/or with other convention al separation processes, have proven to be clean chemical processes. T he study of a tanning process showed that many operations can be impro ved integrating them with membrane operations. The steps studied in th is work were: enzymatic skins unhairing, degreasing of pickled sheepsk ins and chromium tanning; furthermore, the recovery and reuse of salts contained in the solution coming from chromium (III) precipitation we re studied. The obtained results realize a reduction in environmental impact, a simplification of depuration processes of waste water, an ea sy reuse of sludge, a decrease of disposal costs and a saving of chemi cals and water.