Sewage treatment device for septic tank

The utility model discloses a sewage treatment device for a septic tank. The sewage treatment device for the septic tank comprises a base layer, an anti-seepage layer, a protective layer, a covering layer and a container, the anti-leakage layer is located above the base layer and comprises a bottom wall and side walls, the side walls are connected to the side edges of the bottom wall and extend upwards, and a cavity is defined by the bottom wall and the side walls; the container is located in the cavity and used for storing sewage. The protective layer is filled between the anti-leakage layer and the container and wraps the container; the covering layer is located above the protective layer. Sewage is stored through the container and can be prevented from being in direct contact with soil, meanwhile, the anti-leakage layer is arranged below the container, even if a small amount of sewage in the container leaks, the sewage can be collected through the anti-leakage layer, and further leakage of the sewage is av