Prefabricated sewage treatment tank with modularized filtering device

The utility model discloses a filtering device modularized prefabricated sewage treatment tank which comprises a sedimentation tank, a filtering tank arranged on one side of the sedimentation tank, a water purifying tank arranged on one side of the filtering tank far away from the sedimentation tank, a water inlet arranged on the side wall of the sedimentation tank, and a filtering module assembly arranged in the filtering tank, the filtering module assembly comprises a first filtering module and a second filtering module, a first circulating opening is formed in the side wall of one end, close to the sedimentation tank, of the first filtering module, a second circulating opening is formed in the other side wall of the first filtering module, and a third circulating opening is formed in the side wall of one end, close to the first filtering module, of the second filtering module; the second circulation opening and the third circulation opening are connected through a connecting pipe, and a fourth circulation