Characteristics of Treatment of Copper Mine Wastewater by Ozone Advanced Oxidation

Abstract

Copper mine wastewater is a rather tough environmental issue. An efficient and effective method is still expected. Ozone advanced oxidation technology is applied to treat copper mine wastewater in this paper. A systematical investigation is performed and the degradation mechanism is revealed. Experimental results show ozone can effectively degrade COD meanwhile all pollutants indexes can meet the strict emission requirement. There are two interesting discoveries in copper mine wastewater treatment process by ozone advanced oxidation. One is COD change with ozone aeration time. COD rapidly decreases initially, followed by a small recovery, but then decreases slightly. The dramatical decrease in the first several minutes results from the oxidation of residual flotation reagents, humic acid-like and soluble microbial product-like. The small recovery is because these substances of protein-like and humic acid-like are oxidized to small molecules. The last slight decrease is due to the further oxidation of these small molecules. Another is ammonia nitrogen change in fluctuations with ozone aeration time. The oxidation CwHxNyOz in residual flotation reagent Xanthate leads the first ammonia nitrogen increase and the following first decrease, respectively. It is followed by another increase and decrease. The second increase is owing to these relatively stable nitrogenous organic matters of protein-like and fulvic acid-like are oxidized to ammonia nitrogen. The last reduce results from the further oxidation of ammonia nitrogen. In a word, ozone advanced oxidation is a promising technology for copper mine wastewater treatment.