Abstract: To explore the effects of ecological floating bed (EFB), a membrane aerated biofilm reactor (MABR), and an integrated device, an experimental study is conducted on their purification efficiency of four types of pollutants–NH4+-N, permanganate index (CODMn), total phosphorus (TP), and total nitrogen (TN) – in water flows with different velocities (2.5, 10 and 20 m/h). The results show that this MABR-EFB integrated device significantly improves purification effect, and its removal rates of the four pollutants are increased by 40% - 44%, 17% - 34%, 13% - 21% and 14% - 30% respectively compared with those of river water self-purification. A comprehensive consideration of all these pollutants indicates that the device performs best under the hydrodynamic condition at the flow velocity of 10m/h, and MABR buffering effect helps widen the flow velocity range applicable to aquatic plants. Under the hydrodynamic conditions tested in our experiment, the device behaves differently in removing different pollutants: in relatively high pollutant concentration, it purification rate increases with the increasing flow velocity for NH4+-N but reaches the maximum at 10 m/h for CODMn, TP and TN; in low concentration in the later stage of the experiment, it has a low purification rate for all the pollutants tested.

Key words: integrated purification device, purification efficiency, purification rate, ecological floating bed, membrane aerated biofilm reactor