Hide unhairing: achieving lower pollution loads, decreased wastewater toxicity and solid waste reduction

摘要

This study aims to diminish the pollution being discharged into wastewaters through changes in the\udunhairing process. To this aim, we are replacing a reductive hair degrading process with a process which\udcombines a reductive hair degrading process with an oxidative hair degrading process. Hydrogen\udperoxide is used to decrease the supply of sulfide as unhairing chemical. As a result, commercially\udacceptable leather regarding both costs and quality is obtained and significant reductions in the\udcontaminant load of the wastewater being discharged are observed. Results indicate that wastewater\udconductivity is cut by 26%, suspended solids decrease by 75%, observable sulfide disappears, while the\udamount of chromium being absorbed by the hides is increased. This leads to considerable savings in the\udchromium salt offer in hide tanning and, consequently, a decrease in the amount chromium in the\udwastewater.