Abstract: A wastewater treatment apparatus of the present invention is configured to biologically filter wastewater through multimedia by consecutively performing two stages (the first and second stages) for a multimedia biological filtration process. A carbon source and coagulant are respectively injected during the first and second multimedia biological filtration processes. The first stage multimedia biological filtration process is carried out in anoxic conditions and the second stage multimedia biological filtration process is carried out in aerobic conditions. The media for the first and second stage biological filtration processes are arranged in large-middle-middle large-small size. Thus, the present invention can secure excellent treated water while minimizing loss of water-head by maximizing reflux capability of solids.

Abstract: A wastewater treatment apparatus of the present invention is configured to biologically filter wastewater through multimedia by consecutively performing two stages (the first and second stages) for a multimedia biological filtration process. A carbon source and coagulant are respectively injected during the first and second multimedia biological filtration processes. The first stage multimedia biological filtration process is carried out in anoxic conditions and the second stage multimedia biological filtration process is carried out in aerobic conditions. The media for the first and second stage biological filtration processes are arranged in large-middle-middle large-small size. Thus, the present invention can secure excellent treated water while minimizing loss of water-head by maximizing reflux capability of solids.

Abstract: Disclosed are a rotor for generating vortex water flow that creates shear intensity for removing solid material adhered to the separation membranes during the processing of water containing pollutant material, and a filtering apparatus employing the same. The rotor consists of a first rotor having first blades and a second rotor having second blades. The first and the second blades are extended in a radial direction from a rotational axis thereof, and are disposed at positions different from each other in the rotational axis direction. The first blades and the second blades have widths different from each other in a circumferential direction around the rotational axis, or disposed at positions different from each other in a circumferential direction. Protrusions can be attached on outer surfaces of the first blades and/or second blades.