Study On Micro-polluted Source Water In ChangXing Harbor District By Enhanced Filteration

Because of the shortage and the increasing pullution of drinking water source,it is less efficiency to the turbidity,oxygen consumed,ammonia nitrogen and heavy metal by the conventional filteration.Enhanced filteration would become a new task in the modern potable water supply.The existing enhanced filtemtion technology mainly focuses on the following aspects:the development and utilization of coated filter,secondary micro-flocculation and preoxidation,biological activated carbon(BAC),ozonation-biological activated carbon(O3-BAC)and combined process.In this thesis,the writer aims at the low tuibidity,high algae and organic substance and heavy metal pollutant of source water in ChangXin habor,and has used the pilot-test researched the removal turbidity,COD_Mn,UV₂₅₄,ammonia nitrogen,nitrite nitrogen,nitrate nitrogen,iron and manganese by BAC-Sand filter,secondary micro-flocculation and PAC-coated filter.The result of the test shows that:(1)The removal of turbidity,COD_Mn,UV₂₅₄,ammonia nitrogen,nitrite nitrogen,nitrate nitrogen,iron and manganese by BAC-Sand filter is mainly in the upper BAC filteration,and the removal rate is 75.8%,33.1%,39.1%,60.6%,62.4%and65.0% respectively.The accumulation of nitrite nitrogen by BAC-Sand filteration can also be easily detected in the test,it has increased to 1.23mg/L.(2)Dual-medium BAC-Sand filter is more efficient than homogeneous sand filter in removing the COD_Mn,UV₂₅₄,ammonia nitrogen,nitrite nitrogen,with the removal rate reaching 41%,49.2%,71.0%and 78.6%,influence color less than 5 and ensurence standing at 100%.The removal rate of turbidity,maganese stands at the same leval,but it is less effective in removing iron.(3)Under the 40h filteration cycle,BAC-Sand filteration rate decreases within a narrow range,and the influence to the water quality is small.(4)Secondary micro-flocculation can enhanced the removal efficiency of the pollutants,and the removal rate increases by 1.1%,3.0%,4.3%and 9%to the turbidity,CODmn,UV254 and iron respectively.(5)PAC-coated sand can remove turbidity,COD_Mn,UV₂₅₄effectively,compared with ordinary sand filter,the removal rate increase by 0.3%,13.8%and 12.4%.It also can treat the high iron polluted water effectively,when the iron content is 1.05mg/L and 1.21mg/L, the removal rate of iron by coated filter is higher 18.1%and 9.1%than ordinary sand filter.