China Nonferrous Metallurgy

On account of the high COD level in smelting wastewater, Xiangguang Copper has made a check from three aspects, i.e., source of wastewater, production process control procedure and production management measures, for control of the COD index in acidic wastewater. The following measures have been taken to reduce COD in wastewater: sulfuric acid concentration is increased to above 4% for purification; technical upgrade and regular inspection and cleaning are carried out to ensure the desorption effect of desorption tower and neutralization-oxidation-aeration effect; hydrogen peroxide circulating solution is added into the desorption circulating solution and sulfide filtrate to preliminarily reduce the COD level in wastewater; hydrogen peroxide circulating solution is added in the carbide slag neutralization process to further reduce the COD level in wastewater. As a result, the COD in the wastewater is controlled within 30~40mg/L, meeting the discharge standard.