wastewater The tanning wastewater was collected directly (without any pretreatment) from the tanning drum of a tannery that per-forms beamhouse and tanning operations, processing 500 hides/day and generating a total average effluent flow of 200 m3/day in addition to 60 m3/day of Cr-containing waste-water. This wastewater was filtered with glass wool before the experiments, according to NBR standards,to remove the suspended solids (shavings and fats).