The Shudy On The Treatment Of Surface Water’s Pollution By Embedded Nitrifying Bacteria Combined With Ultrafiltration Membrane Processing

With the current industrial development and social progress, source waterpollution is getting worse. The treatment technology of Micro-polluted source waterhas become an important and urgent research topic.The study is based on the contractof technology transformation in the water company of Nantong Port signed by Literscompany of Suzhou,Jiangsu Province,Nantong City,and water companies ofNantong.By the existing water sources of Nantong Port,the combination of theembedded nitrifying bacteria particles fluidized bed and coagulation-ultrafiltration ofthe pilot test is explored,By the Experiment over150days,the main results andconclusions are as follows:（1） As a pretreatment before membrane,the optimum dosage of coagulant （FeCl3）is between2.0and2.5mg/L.（2） Whether the low turbidity water in the period of average water level or highturbidity in the period of flood water level, ultrafiltration membranes have a verygood turbidity removal effect.By this method, the effluent turbidity is lower than0.1NTU, and the average turbidity is about0.05NTU, the effluent turbidity of theconventional process is0.45NTU,Those show that the effluent turbidity ofultrafiltration membranes is superior to conventional drinking water treatmentprocess.（3） The average removal rate of CODMnby the treatment of coagulation-Ultrafiltration is64.38%, while the average removal rate of CODMnby the treatmentof embedded nitrifying bacteria-coagulation–Ultrafiltration is66.56%.The averageremoval rate of CODMnby the conventional treatment is46.03%, which indicats thatthe two two-stage removal process on the CODMnare both superior to theconventional technology,and the effluent all meets the national drinking waterstandards.（4） The embedded nitrifying bacteria fluidized bed has a good effect on theremovement of NH₃-N,when HRT≥1h，DO≥4mg/L the removal rate is ahout70%.（5） By the biological pretreatment process of embedded nitrifying bacteriafluidized bed,the average removal rate of NH₃-N is68.74%, the average removal rateof NH₃-N by embedded nitrifying bacteria-coagulation-ultrafiltration andcoagulation-Ultrafiltration are89.92%and52.89%respectively. Thus, the embedded nitrifying bacteria fluidized bed,as a biological pretreatment has a good effect on theremovement of NH₃-N.（6） The removal rate of E. coli,bacteria by ultrafiltration membranes is almost100%,and the removal rate of iron is70.12%,the iron content of effluent is less than0.1mg/L.（7） From infrastructure expenses and the land cost of consideration,thecombination process with ultrafiltration membrane as the core is far lower thanconventional water treatment process;From the operation cost consideration,thecombination process with ultrafiltration membrane as the core is higher thanconventional water treatment process,The former operation cost is0.515yuan/m3; thelatter’s operation cost is about0.3yuan/m3.