| abstract |
(57) [Problem] To provide a method of purifying stored water by using a hollow fiber membrane to maintain the stored water at high quality and to keep initial costs low. SOLUTION: Water is stored by a hollow fiber membrane having a fraction particle size of 1 to 10 μm (for example, pool water, bath water, hot spring water, home bath water, aquarium water tank water, water tank water for breeding aquatic animals, artificial pond). Water, circulating temperature regulating water, circulating cooling water, circulating washing water, circulating processing water, boiler circulating water, etc.). The hollow fiber membrane preferably has a fractionated particle size of 2 to 5 μm. |