Research Of Efficient Treatment Technology Treating Wastewater In Waterwork

Traditional concentrating technology and new-style concentrator are the prevailing technologies in the field of wastewater treatment in waterworks, with advantages of high yield, convenient management and ect. However, existed treatment processes occupy large area, and are always consisted of many complicated constructions. Pellet coagulation technology is a new technique possessing high-rate sedimentation and separation. Compared with conventional flocculation process, Pellet Coagulation Technology possesses advantages such as high yield, lower water content in thickened sludge and better dewatering character of conditioned sludge, when applied in the treatment of alum sludge of waterworks.In this paper, by taking the wastewater from Yangliuqing water plant in Tianjin City as the object, a dynamic experimental study is carried out on concentrating ferric flocs sludge by pellet flocculation process with the capacity of 1.3～5.4m~3/h. Experimental results shows that:(1)The result of optimized experiment indicated that, taking the static mixer or tubular coagulator as mixing install will get better result than others. When applying static mixer as mixing mstall, the maximal upflow rate could reach 80cm/min, and effluent turbidity could be less than 5NTU; when applying tubular coagulator, effluent turbidity could be less than 3NTU, with a maximal upflow rate of 70cm/min.(2)A pilot experiment, taking the static mixer as mixing install, was carried out on the application of Pellet Coagulation Concentration Technology to water plant wastewater. When SS in the influent is 103～1154mg/L, the proper operational conditions should be PAC dosage at 5.1～15.3mg/L, PAM(molecular weight of 10～12 million) dosage at 0.3～2.7mg/L, optimal rotating rate of 10rad/min. In the pilot experimental condition ,the maximal upflow rate of Pellet Fluidized Bed was in negative proporation to the SS of raw sludge water: water upflow rate in the Pellet Fluidized Bed could reach 80cm/min when the SS of raw water was 318mg/L; while the corresponding maximal upflow rate was decreased to 35cm/min when the SS of the raw sludge ascended to 1154mg/L. Sludge recirculating pump was applied when SS of raw sludge water was too low, and the relationship between sludge recirculating quantity and raw sludge water SS was studied in this condition.(3)In this case the effluent turbidity and the moisture content of the sludge can be reduced less than 5NTU and below 97% respectively. Moreover, the sludge sedimentation rate can exceed 10mm/s.(4)Analysis was carried out based on the result of pilot experiment in the discussion; we expound the influence of process controlling parameters on the effluent and the character of suspended layer. At last, we study the quantitative relationship between floc concentration of suspended layer and PT,ALT,v andω.