Productive experiment on tannery wastewater treatment

Leather industry was a dominant industry in China, but the considerable tannery wastewater resulted in several serious environmental problems, which brought huge harm to human health. In this paper, coagulation-sedimentation combined with biological contact oxidation and SBR was explored for tannery wastewater treatment. Under the hydraulic retention time of 15h of biological contact oxidation process, both the COD and NH₄⁺-N removal efficiency was more than 85%, and the shock of raw water concentration has little influence on this process. In the subsequent SBR process, the removal rate of 65% and 85% of COD and NH₄⁺-N could be achieved respectively under the DO of 2mg/L and aeration time of 6h. The overall effluent of COD was 90mg/L and NH₄⁺-N was 4mg/L approximately, which showed evident superior to the traditional physico-chemical and biochemical processes. The combined process was suitable for tannery wastewater treatment and showed favorable resistance to shock loading.