Study on Biological Aerated Filter (BAF) of Algae-contained Micropolluted Water

摘要

Using NaCl modified zeolite with high specific surface area as filter media, algae-contained micropolluted water was treated with biological aerated filter (BAF) process. The removal efficiencies of the process on micro-pollutants and removal mechanism of algae-contained micropolluted water were investigated and studied. The results showed that better removal efficiency was obtained in turbidity, Chlorophyll-a, UV_(254), and COD_(Mn) when algae-contained micropolluted water was treated by BAF. The optimal process parameters of the treatment of algae-contained micropolluted water with BAF were gases/water ratio of 0.5～2.5, backwash cycle of 3～5 d, air/water backwash strength of 5～7 L/(m~2·s), air backwash strength of 13～17 L/(m~2·s), backwash time of 15～20min, temperature of 25～30°C, pH value of 7.8～8.5 and hydraulic load of 0.23～0.35 m~3/(m~2·h). The results of continuous running for 21 days showed that the removal efficiency of turbidity, Chlorophyll-a, UV_(254), and COD_(Mn) were up to 71.61%, 81.35%, 28.34% and 32.97% respectively under the conditions of these optimal parameters, and the effluent water could meet Grade II of the Drinking Water Quality Standards (CJ 3020～1993). This study could provide technical information for town water plant reconstruction of Taihu Lake and Chaohu Lake basin.