To provide a fibrous filter medium the maintenance of which is facilitated by withdrawing water from a filtration tank and drying the filtration tank when a filtering operation is made to stand by or stopped and by which a problem such as a bad smell when the filtering operation is stopped is solved.

This fibrous filter medium keeping a specified shape is obtained by folding a fabric consisting of a fiber having the surface formed from a polyolefin-based polymer and melting or softening a part of the polyolefin-based polymer of the folded fabric. When the filtering operation using this fibrous filter medium is completed, the fibrous filter medium in the filtration tank is washed, the water retained in the filtration tank is discharged and the filtration tank is made to stand ready for the next filtering operation.

COPYRIGHT: (C)2006,JPO&NCIPI