| The combined method of“ozone oxidation-biological aerated filter(BAF)-reverse osmosis”was the common technology in advanced treatment for wastewater of textile and dyeing industry in recent years.In this study,some optimized researches including preposed biosorption,optimized ozone oxidation-BAF and recycled reverse osmosis concentrate were carried out and studied for solving the shortage such as high operating cost,large space occupation and low rate of wastewater reusing of the common method.Anaerobic sludge(AS)and inactive anaerobic sludge(IAS)were both picked as bio-adsorbents for adsorption of nonionic refractory organic matter PVA.It was found that the amounts of PVA adsorbed by AS was about 24.6 mg/g which was about double of PVA adsorbed by IAS.Extracellular polymeric substance adsorbed about 45.1%of total amounts in AS adsorption and physical adsorption played an important role in PVA biosorption with AS.Refractory cationic dye,basic fuchsin(FB)was adsorbed by PMDA-AS which was made by modifying AS with pyromellitic dianhydride.The results shown that the maximum adsorption capacity of PMDA-AS for FB was 231.5 mg/g which was as three times as that of AS without modification,adsorption was better with pH of 8.0 and chemical adsorption played an important part in this process.PEI-AS which was made by modifying AS with polyethyleneimine and AS were also used for adsorption of refractory anion dye,acid rose red B(ARRB).Results showed that adsorption capacity of PEI-AS was 85.3 mg/g which was as four times as that of AS without modification,adsorption was better with pH of 4.0 and chemical adsorption was dominant.Adsorption of AS,PMDA-AS and PEI-AS met pseudo secondary dynamic model and all the behaviors were mainly monolayer adsorption and endothermic process.In addition,AS,PMDA-AS and PEI-AS were all used to adsorb the pollutants of two-stage biochemical effluent(TSBE)of textile and dyeing wastewater and organics removal efficiency indicated that PMDA-AS was more efficient than AS which was more efficient than PEI-AS.The refractory organics removal efficiency was about 20.6%when 0.75 mg/L AS was added to TSBE of textile and dyeing wastewater.The activation and domestication of integrate ozone-BAF was achieved based on the separate activation and domestication of ozone oxidation area and BAF area and the results proved that integrate ozone-BAF was available efficiently for disposing TSBE of textile and dyeing wastewater.The TSBE was purified efficiently when 35 mg/L ozone was added to integrate ozone-BAF in 3.0 h which including 1.0 h ozone oxidation,0.5 h buffer and 1.5 h BAF degradation.With an operation of 90 days,practical TSBE and effluent after preprocessing with biosorption were disposed by integrate ozone-BAF and by appropriate adjustment of ozone dosage chroma,COD and SS in effluent was lower than 8 times,40 mg/L and 14 mg/L,respectively.The pollutant removal mechanism accorded to hydroxyl radical mechanism and microbial in middle part of BAF played a main role in removal of chroma and COD.Reverse osmosis concentrate was disposed by combined process of persulfate oxidation and soda-lime.Results shown that COD was less than 21.5 mg/L and concentration of sodium sulfate in effluent was higher than 10 g/L with initial pH of 5.0,temperature of 75 degree centigrade and dosage of persulfate of 1 000 mg/L.Effluent was then treated by soda-lime process.Results shown that hardness of effluent was less than 17.5 mg/L with 150 mg/L of soda and 800 mg/L of lime,respectively.After that,effluent was reused in dyeing process.Research results indicated that K/S variation of textile from recycling test was acceptable,total color differences values was less than 1.0 and color fastness was above grade three.The operating cost was calculated without electric charge and labor cost.The biosorption cost was about 0.09 yuan/m~3 for AS,and the integrate ozone-BAF cost was about 0.26 yuan/m~3,and the cost for recycling concentrate was about 4.65 yuan/m~3.The optomized process could lower about 0.05 yuan/m~3 than separated ozone-BAF,and reduce about 60%space occupation and improve about 25%rate of wastewater reusing. |
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