A multi-ply filter and a water-purification kit. The filter comprises at least two adjacent plies, wherein at least one of the plies comprises a multi-density fibrous structure having a plurality of discrete pseudo-apertures disposed therein, the pseudo-apertures having individual areas of at least about 3 square millimeters and a basis weight from about 0.1 to about 5 gram per square meter. The kit comprises the multi-ply filter and a water-purification composition comprising a flocculation agent and a coagulation agent.
