A new device, method, and system are disclosed that provide for removal of undesired materials from a contaminated fluid. Materials present in the fluids are kept in motion in one or more filter cassettes that include disc aerators that improve contact times with the sorbents and that rotate the filter media to pump contaminated water through the filter media for treatment of the contaminated fluids. The device and system provide containment of sorbent fines that keeps the filter media free from clogging.