Study On Combined Process For Turbidity Romoval From Butyl-Acrylate Wastewater

Butyl acrylate wastewater had characteristics such as high turbidity, high COD,high salt and extremely hard to deal with. Previous research results showed that thebipolar membrane electrodialysis technology could recycle organic acid from thewaste water, reduce wastewater salinity, decrease the difficulty of the subsequentbiochemical treatment, and had good application prospect. To prevent turbiditymaterial in wastewater causing membrane fouling of electrodialysis processing unit,this study aimed to butyl acrylate wastewater, and applied the coagulation-sedimentation-filter material filtration-inorganic ceramic membrane filtration processfor processing research.The results showed that: static mixing was superior to the mechanical stirring forthe coagulation reaction of butyl acrylate wastewater in the comparative study of celltechnology, the sedimentation was superior the flotation for slurry separation ofcoagulation water; for the filter test of coagulation and sedimentation of water, thedual-media filter was superior to the single sand filter.It was indicated that coagulation conditions, such as pH, coagulant dosage,stirring speed, duration, had significant influence on effluent turbidity ofcoagulation-sedimentation and dual media filter, membrane fouling of ceramicmembrane filtration. Effluent turbidity of turbidity of dual media filter has significantpositive relation with ceramic membrane fouling resistance, but the trends of turbidityof coagulation-sedimentation and ceramic membrane fouling is not completelyconsistent. The optimum conditions for coagulation-sedimentation of butyl acrylatewastewater was: pH5~6, dosage of PAC was150mg/L, dosage of PAM was15mg/L,the wastewater flow was40L/h (flocculation time was68min, settling time was75min), the first stirring speed of grid flocculation was250rpm, the second one was150rpm, the third one was60rpm.The optimum conditions of coagulation-sedimentation by dual media filter wasthat the filtration velocity was15m/h, the intensity of the backwash was73.3m/h, theexpansion of the filter layer was50%the backwash time was7min.The backwashwater could be mixed with the fresh wastewater to coagulation-sedimentation process.The optimum conditions of effluent of dual media filter by ceramic membranefiltration was that the membrane pore size was200nm, operating pressure was0.06~0.20MPa, filter temperature was25~35℃, the membrane surface flow rate was3.6~7.1m/s. The Ceramic membrane filtration concentrated water could be mixedwith the fresh wastewater to coagulation-sedimentation process.The results of a combined process of coagulation-sedimentation, dual mediafilter and ceramic membrane filtration continuous operation showed that thecombined process could remove the turbidity substances in butyl acrylate wastewater.When the turbidity of waste water was15~30NTU, the effluent turbidity of combinedprocess remained at around0.5NTU. The results of electrodialysis device continuous operation showed that the effluent of the combined process removed polyvalent ionsby ion exchange, it could ensure the stable operation of the ceramic membrane unit.