Treatment Of Biologically-treated Effluent Of Dye Wastewater By Heterogeneous Catalytic Ozonation Technology

In this research,a suitable reaction system was established,the treatment performance of heterogeneous catalytic ozonation for the primary biochemical effluent of dye wastewater was studied,the improvement of the biodegradability of the dye wastewater was explored,and the ozonation path and mechanism of the degradation of p-chloro-o-nitroaniline was speculated.First,the selection of catalysts and operation parameters optimization experiments were conducted,and the optimal reaction system was established.The results show that the catalytic effect of manganese sand is not stable,and the best catalyst is the labratory-made catalyst.The optimal operating parameters include the ozone concentration of 25 mg·L-1,contact time of 20 min,gas flow velocity of 0.2 L·min-1 and ozone dose of 200 mg·L-1.In addition,the catalysts used for 90 consecutive days were investigated by ICP,BET,SEM and EDS techniques.Under the optimal conditions,the average removal rate of COD value was about 32%,chroma removal rate was more than 95%.Then several indexs of wastewater biodegradability were analyzed and the organic compounds in the wastewater were qualitative analyzed.The results showed that SOUR increased from 0.0403 mgO2·(gMLSS·min)-1 to 0.1903 mgO2·(gMLSS min)-1,and the biological toxicity decreased from 60%to 0%,the results of GC-MS testing showed that the aniline,phenols and nitro toxic pollutants coule be completely removed from wastewater treated by heterogeneous catalytic ozonation,and these results together showed that this technique can improve the biodegradability of wastewater.The continuous experimental results show that the heterogeneous catalytic ozonization technique can effectively improve the efficiency of secondary biochemical processing.Finally,the possible degradation mechanism and pathways of p-chloro-o-nitroaniline was studied,and the reaction kinetics was established,which provided data support and theoretical support for the application of heterogeneous catalytic ozonation technology in the treatment of practical dye wastewater.The results showed that the main degradation of the organic matter is the common role of hydroxyl and ozone,and the degradation of organic compounds is the quasi-first reaction.