Leather and leather products are one of the most traded products worldwide.

As a result of processing 1 ton of leather, 200 kg of final product is produced and 50,000 kg of water is used. Pre-tanning and tanning processes contribute to approximately 90% of the total pollution caused by the leather industry. 64% of the wastewater from leather processing originates from the pre-tanning process, 23% from the tanning process, and 12% from the retanning process. Chromium salts, which are not used at the rate of 40% during the tanning process, are discharged with the final wastewater and pose a serious threat to the environment. Salinity, organic load (chemical oxygen load or demand, biological oxygen demand), inorganic matter, dissolved, suspended solids, ammonia, total kjeldahl nitrogen (TKN), specific pollutants (sulfide, chromium, chloride, sodium and other salt residues), and heavy metals etc. contains pollutants.