BAF (biological aerated filter) has the functions of removing SS, COD, BOD, nitrification, denitrification, phosphorus removal and AOX (harmful substances). Biological aerated filter (BAF) is a new technology which integrates biological oxidation and suspended solids interception.
Process characteristics
① The one-time investment is 1 / 4 lower than that of the traditional method; ② the occupied area is 1 / 10-1 / 5 of the conventional process, and the operation cost is 1 / 5 lower; ③ the inflow requires 50-60mg / L of suspended solids, which is better combined with the first-class enhanced treatment, such as the use of hydrolysis acidification tank; ④ the filler is mostly shale ceramsite, with a diameter of 5mm, and a layer height of 1.5-2m; ⑤ the secondary sedimentation tank may not be set for the reverse flow of water down and gas up.
Compared with the ordinary activated sludge process, BAF has the advantages of high organic load, small floor area (1 / 3 of the ordinary activated sludge process), low investment (30% savings), no sludge bulking, high oxygen transfer efficiency, and good water quality. However, it has strict requirements on the influent SS (generally SS ≤ 100mg / L, preferably SS ≤ 60mg / L). Therefore, the influent needs to be pretreated 。 At the same time, its backwash water volume and head loss are large.
Biological aerated filter, as a combination of biological oxidation and suspended solids interception, saves the follow-up sedimentation tank (secondary sedimentation tank). It has the characteristics of large volume load, large hydraulic load, short hydraulic retention time, less capital investment, good effluent quality, low operation energy consumption and low operation cost.
