Regeneration method for filtration apparatus, filtration apparatus and water treatment apparatus

A regeneration method for a filtration apparatus that has a filter layer formed by filling a solid filter material formed with a protrusion on a surface, and passes water to be treated containing suspended matters through the filter layer to perform filtration of the suspended matters, the regeneration method for a filtration apparatus comprising the steps of:

• backwashing the filter layer by passing washing liquid through the filter layer in a direction opposite to a passing direction of the water to be treated;
• collecting backwash filtrate generated by the backwashing;
• and
• passing the backwash filtrate through the filter layer toward the passing direction of the water to be treated, and reforming a protrusion on the surface of the solid filter material.

A filtration apparatus comprising:

• a filter layer formed by filling a solid filter material formed with a protrusion on a surface;
• a washing-liquid feeding part that passes washing liquid through the filter layer in a direction opposite to a passing direction of water to be treated to perform backwashing;
• and
• a backwashing control part that controls a passing speed of the washing liquid so as to restrain movement of the solid filter material to retain the protrusion on the surface of the solid filter material.

A filtration apparatus comprising:

• a filter layer formed by filling a solid filter material formed with a protrusion;
• a washing-liquid feeding part that passes washing liquid through the filter layer in a direction opposite to a passing direction of water to be treated to perform backwashing;
• a collecting part that collects backwash filtrate generated by the backwashing;
• and
• a protrusion-reforming part that passes the collected backwash filtrate through the filter layer toward the passing direction of the water to be treated, and reforms the protrusion on the surface of the solid filter material.