A Pilot Study On Advanced Treatment Of Comprehensive Wastewater Of Dyeing And Finishing Of Textile By Ozone Catalytic Oxidation

Dyeing and finishing of textile industry belongs to enterprise of high consumption of water and heavy pollution,and enterprise is distributed along the river,Dyeing and finishing of textile industry accounts for a significant contribution ratio of the water pollutants of river basin emission.As the latest "Discharge standards of water pollutants for dyeing and finishing of textile industry"(GB4287-2012)was promulgated,and respond to which the nation accomplish the pollutants discharge reduction task of "twelfth five-year",and reduce the pollution load of the key river valleys,it is necessary to treat comprehensive wastewater of dyeing and finishing of textile deeply,to further remove the pollutants in the wastewater to meet the new discharge standard and cut down the pollution load of the key river basin.The pilot study of this research subject is carried out in a large sewage treatment plant in an industrial park of printing and dyeing of textile in a certain city in zhejiang province,and regard high-efficiency clarifier effluent as the research object of the pilot study.In this paper,basing on summarizing advanced treatment of the dyeing and finishing of textile wastewater,the influencing factors of ozone catalytic oxidation,types of catalysts of catalytic ozone oxidation,ozone generation system,and the structure of the ozone catalytic oxidation reaction device comprehensively,put forward using supported catalysts of metal ions for catalytic ozonation process as the advanced treatment process of comprehensive wastewater of dyeing and finishing of textile.Through laboratory test in the wastewater treatment plant,studying the factors that affect dyeing and finishing of textile wastewater treatment by ozone catalytic oxidation,such as:ozone dosage,reaction time(HRT),pH and other factors;Through the design of orthogonal experiment and the visual analysis of orthogonal experiment results,determine the primary and secondary order of the factors influencing the ozone catalytic oxidation as well as the optimal laboratory conditions of ozone catalytic oxidation;under the optimal conditions,after the small scale experiment is verified,ozone catalytic oxidation optimum reaction conditions are obtained;Laboratory test showed that the best reaction conditions of the catalytic ozone oxidation is: ozone dosing quantity is 145 mg/L,reaction time is 100 min,pH is 6.0.Under the optimum reaction conditions,the removal rate of COD of ozone catalytic oxidation process is 67%,the concentration of effluent COD is less than 50 mg/L.During the pilot experiment,the comprehensive wastewater of dyeing and finishing of textile is treated by a pilot plant of ozone catalytic oxidation,and the concentration of effluent COD is less than 50mg/L,the feasibility and stability of which as well as the optimum condition is studied;In addition,the ozone catalytic oxidation on the removal of ammonia nitrogen and chromaticity as well as biodegradability improvement of wastewater is also studied.Finally,the cost of treatment of wastewater of the dyeing and finishing by ozone catalytic oxidation was calculated.In the process of the pilot experiment,combining the optimum reaction conditions of laboratory test with the actual characteristics of water quality of high-efficiency clarifier effluent,in the case of not adjusting the pH and temperature of the wastewater entering the pilot plant,the optimum reaction conditions for the determination of ozone catalytic oxidation by continuous debugging were as follows: ozone dosing quantity is 150 mg/L,hydraulic retention time is 100 min.Under the optimum reaction conditions,the water quality of the pilot plant of ozone catalytic oxidation effluent can be steady: effluent COD ?50 mg/L,chromaticity ? 30 times,and meet the“Discharge standard water pollutants of urban sewage treatment plant ”(GB18918-2002)in the level of A standard;the removal rate of COD was about 65%,the removal rate of chroma is about 70%,and the processing costs is about 2.5yuan per tons of water.In addition,improvement of the effluent biodegradability of the high-efficiency clarifier after treated with the pilot plant of ozone catalytic oxidation is small,and is still less than 0.1;the effluent concentration of ammonia nitrogen is below 4.2 mg/L basically,and removal rate is about 10%.For the depth processing of the dyeing and finishing of textile wastewater,the study results of pilot plant of ozone catalytic oxidation provide an alternative to the technical and design parameters.