Research On Treatment Of Polluted Raw Water By O₃-BAC And Micro-flocculation Enhanced Filtration And Combination Process

In recent years,with the increasingly serious pollution of water sources,as an important process of advanced treatment,O₃-BAC process is widely used in Water Treatment Plant which can remove ammonia nitrogen,nitrite nitrogen,organic matter?UV254,CODMn,DOC?etc effectively,also the color,smell,taste and lots of water quality have been improved.However,if O₃-BAC process as the last procedure in Water Treatment Plant,the turbidity of the effluent could not stable reach less than 1NTU?“Hygienic Standards for Drinking Water” GB5749-2006?and even more difficult to achieve less than 0.1NTU?“Evaluation Standards for Urban Water Supply in Modern Waterworks of Zhejiang” 2013 edition?,a number of particles of the effluent and microbial leakage and other security risks still exist.After Micro-flocculation and Enhanced Filtration Process combined with O₃-BAC Process in Water Treatment Plant,an excellent treatment result that the turbidity of effluent is equal to or less than 0.1NTU and the number of particles above 2?m is equal to or less than 30 p/mL.To solve the above problems,on the one hand,the article studied the effect of removal of pollutants in water by O₃-BAC Process and Micro-flocculation and Enhanced Filtration Process and combined process,on the other hand,the effect of O₃-BAC on micro-flocculation and enhanced filtration were investigated.The main research contents and conclusions are listed as following:?1?O₃-BAC Process has good treatment result on pollutants.The results showed that during the experience,the average removal rate of UV254,CODMn,DOC,ammonia nitrogen,nitrite nitrogen are 46.2%,33.8%,29.5%,65.3%,84.8%,respectively.the average value of UV254,CODMn,DOC,ammonia nitrogen,nitrite nitrogen are 0.033cm-1,1.84mg/L,2.36mg/L,0.03mg/L,respectively.?2?The removal rate of organic?UV254,CODMn,DOC?were inconsistent in Ozone contact chamber and biological activated carbon pool.On the contribution rate of UV254 removal,the ozone contact chamber is higher than that of biological activated carbon pool.On the contribution rate of CODMn,DOC removal,the ozone contact chamber is lower than that of biological activated carbon pool.?3?The optimal coagulant dosage?PAC?was 5mg/L and 10mg/L which the effluent of biological activated carbon pool?turbidity range is 0.15⁰.33NTU?and sedimentation?turbidity range is 1¹.45NTU?were obtained respectively by coagulation test results.Under the optimal dosage of coagulant,the average removal rate of turbidity,UV254,CODMn,the number of particles above 2?m are 83.2%,16.3%,9.7%,98.3%,respectively.?4?The influence of O₃-BAC Process on the micro-flocculation and enhanced filtration Process is as follows: in effect of ozone treatment on combination process,If ozone was added,the turbidity of effluent stabilized at 0.02⁰.07 NTU,without ozone,the turbidity of effluent could not equal to or less than 0.1NTU.In colloidal stability,Zeta potential of O₃-GAC effluent ranged from-5 to 0 mV,from micro-flocculation to sand filter process,Zeta potential increased to close to zero further,colloids extremely unstable state.Turbidity and the total number of particles were increased in the effluent of O₃-GAC Process and it is beneficial to between particles or particles and filter media collision probability.