UV254 removal and effect factors from micro-polluted source water by biological sand filter

Based on operational characteristics of the biological sand filter, it was studied on UV₂₅₄ removal effect in micro-polluted source water by biological sand filter, compared with the natural biofilm formation and inoculated biofilm formation methods through experiment. The influence factors such as temperature, filter velocity and height of filter layer were analyzed for removing UV₂₅₄. Also the correlation of DOC and UV₂₅₄ were studied. The results show that the biological sand filter can remove UV₂₅₄ effectively in the micro-polluted source water, the removal rate of UV₂₅₄ is 19.47% to 34.74%. The natural biofilm formation method has better UV₂₅₄ removal than the inoculated biofilm formation method. The water temperature has conspicuous effect the removal UV₂₅₄. The removal rates of UV₂₅₄ is 12.45% to 31.96% separately in biological sand filter at 5-10 to 15-20 temperature; the relational expression is y=1.7558x+0.023, R²=0.7961. The removal rate can reach to total removal 85% in the 45cm height of filter layer. The best filter velocity is 3-4m/h, at this condition, the removal rate reaches 34.7%. The DOC and UV₂₅₄ of saw water has better correlation, the relational expression is y=0.025x+0.053, R²=0.8838.