Filtration process using hollow fiber membrane module

A filtration process using a hollow fiber membrane module including a large number of hollow fibers bundled together therein as porous hollow fiber membranes:

• comprising the filtration step of passing raw water containing fine particles through the pores of said hollow fibers from the outsides thereof to the insides thereof to trap said fine particles on the outer surfaces of said hollow fibers while draining filtrate obtained on the insides of said hollow fibers out of said hollow fiber membrane module, the cooling step of lowering the temperature of water in said hollow fiber membrane sufficient to substantially reduce roughening of the surfaces and occlusion of the pores of said hollow fiber membranes when vibrated module to cool said porous hollow fiber membranes, the scrubbing step of charging bubbles into water around the outer surfaces of said hollow fibers dipped in water to agitate said water around the outer surfaces of said hollow fibers to vibrate said hollow fibers, thereby exfolidating said fine particles trapped on the outer surfaces of said hollow fibers, and the drain step of draining the resulting waste water containing the exfolidated fine particles out of said hollow fiber membrane module.