NOVELTY - The sewage treatment plant comprises a tube with an embedded shell and an inner cavity. A stirring device is arranged in an inner cavity of the tube. An aeration device is arranged in a bottom portion of the inner cavity of the tube. A water bath layer water inlet tube and a water bath layer water outlet tube are connected with the shell of the tube. A reaction layer water inlet pipe and a reaction layer water outlet tube are connected with an inner cavity of the tube. A filler is suspended between an upper grid and a lower grid, where the lower and upper grids are matched with each other.    USE - The plant is useful for treating sewage (claimed) including domestic sewage and industrial sewage.    ADVANTAGE - The plant can treat increased amount of sewage in an automated manner.    DETAILED DESCRIPTION - The sewage treatment plant comprises a tube with an embedded shell and an inner cavity. A stirring device is arranged in an inner cavity of the tube. An aeration device is arranged in a bottom portion of the inner cavity of the tube. A water bath layer water inlet tube and a water bath layer water outlet tube are connected with the shell of the tube. A reaction layer water inlet pipe and a reaction layer water outlet tube are connected with an inner cavity of the tube. A filler is suspended between an upper grid and a lower grid, where the lower grid and the upper grid are matched with each other. The filler is prepared by processing a plastic fine spherical powder using a three-dimensional (3D) printing technology, where the plastic fine spherical powder is sieved with 100-1000 meshes filter. The filler has a honeycomb-shaped spherical structure with a particle size of 30-150 mm. The tube further comprises a cylindrical cover with a set of discharge holes. The shell and the inner cavity of the tube are in a cylindrical shape with a diameter ratio of 2:1-5:1. The water inlet tube is arranged on a bottom layer of the tube. The upper and lower grids are provided with a polygon mesh. The sewage treatment plant further comprises a control device that is connected with the aeration device through a compressing pump and includes a solution probe and a temperature probe. An electromagnetic valve is connected with the water inlet and outlet tubes. A pH on-line monitor is arranged in the inner cavity of the tube.