Multistage fiber filtering apparatus capable of selectively filtering

A multistage fiber filtering apparatus, comprising:

• an enclosure configured to include an upper box and a lower box communicating with the upper box;
• a strainer configured to be installed in the upper box along a longitudinal direction;
• a plurality of fiber yarn media configured to surround an outer circumferential surface of the strainer to form a first filtering layer;
• a plurality of fiber ball media configured to be built in the lower box to form a second filtering layer;
• a first pipe configured to be formed on one side wall of a lower portion of the upper box and to introduce the raw water;
• a second pipe configured to be formed on one side wall of a lower portion of the lower box and to discharge filtered water;
• and
• a third pipe configured to be formed on one side wall of an upper portion of the lower box and to introduce the raw water or discharge the filtered water,
• wherein a first filtration mode of raw water passing through the fiber ball medium, a second filtration mode of the raw water passing through the fiber yarn medium, or a third filtration mode of the raw water passing through both of the fiber yarn medium and the fiber ball medium, is selectively operated depending on turbidity of the raw water, and
• wherein the raw water is selectively introduced into the first pipe or the third pipe depending on the turbidity and is selectively discharged through the second pipe or the third pipe depending on the turbidity.