Research On Technology And Equipment Of Treatment Of Printing And Dyeing Wastewater By Fe-C Micro Electrolysis-biofilm-advanced Oxidation

Under the severe environmental situation,printing and dyeing wastewater treated by traditional technology of physicochemical-biochemical process failed to reach the emission standard,Fe-C micro electrolysis/biofilm/advanced oxidation process was structured to treat printing and dyeing wastewater for reaching drainage standard,the optimum operation parameters were determined through the study of each process unit,three dimensional virtual simulation and numerical simulation were used to optimize the design of the pilot-scale equipment with high performance,study on the effectiveness of the pilot-scale equipment,and the law of degradation of organic pollutants by different process units in the process of treatment was discussed.?1?In the optimization experiment of Fe-C micro electrolysis/biofilm/advanced oxidation process,the optimum parameters were determined by single factor and orthogonal test.The optimum process parameters for Fe-C micro electrolysis were as follows:pH value was 3,residence time was 1.5 h,gas water ratio was 10:1,the removal rate of COD reached 55.54%and the chromaticity removal rate was 90.12%.The optimum process parameters for biofilm were as follows:the sludge reflux ratio was 50%,the nitrification liquid reflux ratio was 200%,DO was 3⁴ mg/L,the removal rate of COD reached 86.3%,the removal rate of NH₄⁺-N reached 85.88%,the removal rate of TN was 78.34%.The optimum process parameters for advanced oxidation were as follows:pH value was 2.5,reaction time was 2 h,the dosage of 10%ferrous sulfate was 7.5mL/L,the dosage of oxidant was 1m L/L,the removal rate of COD was up to 78.5%and COD was19.7mg/L.?2?The pilot-scale equipment was designed and optimized on the basis of combined process,the swirl aerator has been proved to have excellent performance,the best aeration effect was achieved in the positive center of anoxic pool and the contact oxidation pool,and the simulation of sedimentation tank got good settlement effect.The size and structure of the equipment was determined,Fe-C micro electrolysis unit included Fe-C micro electrolysis pool,neutralization tank,sedimentation tank,and the size were 2 m*0.5 m*1.4 m;biofilm unit included anoxic biofilm pool,biological contact oxidation tank and sedimentation tank,the size were 3 m*0.5 m*1.4 m;the advanced oxidation unit included advanced oxidation pond,neutralization tank and sedimentation tank,the size were 1.5 m*0.5 m*1.4 m.The PLC automatic control system was designed for controlling the operating parameters accurately,and the final virtual assembly was finished,the pilot equipment of high performance for treating printing and dyeing wastewater was obtained.?3?The pilot equipment was studied for more than 2 months,during the process of operation,the biofilm based on basalt fiber filler was composed of 212 genera with rich flora,greatly improving the removal effect and guaranteeing effluent quality.The removal of COD,TN,NH₄⁺-N,TP,chroma was high with the combined treatment,effluent COD was 24 mg/L,TN was 4.07mg/L,NH₄⁺-N was 1.87 mg/L,TP was 0.068 mg/L,chroma was 3 times,and the removal rates were 97%,84.6%,90.8%,87.6%and 98.8%,respectively,effluent fully meted the textile dyeing and finishing industry emissions requirements of the"Taihu Lake area urban sewage treatment plants and key industrial sectors of major water pollutant emission limits"?DB32-1072-2007?,operating costs total of about 3.864 yuan/t,the consumption and energy consumption of pilot system were reduced by the application of PLC automatic control system,meanwhile,the operation parameters of the process system were efficiently operated under the optimal conditions,which ensured the stable discharge of the effluent.?4?The oxidative degradation products were studied by UV spectroscopy and GC-MS,it was found from the migration and degradation of organic compounds in the wastewater,effluent from iron carbon micro electrolysis unit improved the biodegradability with aromatic organic pollutants increased,and amine organic pollutants reduced,amines were maximum removed in biofilm unit,aromatic organic compounds were effectively oxidized and degraded by advanced oxidation units,and the removal of amines was poor,the organic pollutants in the wastewater were removed greatly by Fe-C micro electrolysis/biofilm/advanced oxidation process,and ensured the effluent to reach the standard.The above research provides technical support for the upgrading of the printing and dyeing industry,it is a strong support for the pollution control and sustainable development of the printing and dyeing industry through the popularization and application of the technology and equipment.