NOVELTY - The device has a rotary disk body provided with a sludge pump, a biological treatment unit and a mud storage tank, a box body, a denitrification tank and an inclined tube sedimentation tank. The denitrification tank, the biological treatment unit, the mud storage tank and the inclined tube sedimentation tank are arranged in a box body and connected with each other through a pipeline. The denitrification tank is utilized to reflux the sewage. A bottom part of the mud storage tank is equipped with a filler large specific surface area for growing multimicroorganisms.    USE - Domestic sewage treatment device.    ADVANTAGE - The device has high energy utilization rate, oxygen conversion rate and microorganism biochemical degradation ability, thus realizing removal of organic matter in sewage. The device is convenient to install and operate, and has prolonged service life and low noise, and can process the sewage without peculiar smell.    DETAILED DESCRIPTION - The device has a rotary disk body provided with a sludge pump, a biological treatment unit and a mud storage tank, a box body, a denitrification tank and an inclined tube sedimentation tank. The denitrification tank, the biological treatment unit, the mud storage tank and the inclined tube sedimentation tank are arranged in a box body and connected with each other through a pipeline. The denitrification tank is utilized to reflux the sewage. A bottom part of the mud storage tank is equipped with a filler large specific surface area for growing multimicroorganisms. The biological treatment unit is connected with the denitrification tank and provided with a shell that is connected with three synchronous rotating biological rotors through an air through hole and a power machine. The rotor is connected with 2-4 rotating multi-stage biological turntables whose each upper part is provided with a foil bio-belt. A carbon steel square tube is arranged in the box body and formed by welding framework part with a glass fiber reinforced plastic wall plate. A multi-cover is fixed on an upper part of the box body. The inclined tube sedimentation tank is provided with a yarn fiber filter screen. A dosing tank is utilized for supplementing microorganism liquid. An INDEPENDENT CLAIM is included for a domestic sewage treatment method.