PROBLEM TO BE SOLVED: To provide a method for sterilizing a demineralizer capable of preventing deposition of a scale on the surface of a reverse osmosis membrane even if sterilization using hot water is repeated and simply sterilizing the demineralizer, and to provide the demineralizer.SOLUTION: Raw water in a raw water tank 2 storing water to be treated used in the demineralizer 1 is heated by a first heat exchanger 3 as hot water supply means. Hydrochloric acid is loaded into the heated hot water from a hydrochloric acid supply device 9 as acid loading means and acid hot water the pH of which is adjusted at not more than the saturated solubility of calcium carbonate is supplied to the reverse osmosis membrane 5. Sterilization by the acid hot water continues for 10 to 60 minutes, the temperature of the reverse osmosis membrane 5 is gradually increased and the sterilization is completed. After the sterilization is completed, the demineralizer 1 is wholly rinsed by pure water or the like when required, thereafter the raw water is removed from the raw water tank 2, the raw water is treated by the reverse osmosis membrane 5, and then the pure water is produced.COPYRIGHT: (C)2006,JPO&NCIPI【課題】熱水での殺菌を繰り返しても、逆浸透膜表面へのスケールの付着が防止でき、簡易に、純水製造装置を殺菌できるようにした純水製造装置の殺菌方法および純水製造装置を提供する。【解決手段】純水製造装置1の被処理水を貯留する原水タンク2内の原水を、熱水供給手段としての第1熱交換器3で加熱する。この加熱した熱水に、酸添加手段としての塩酸供給装置9から塩酸を添加し、炭酸カルシウム飽和溶解度以下のpHに調整した酸性の熱水を逆浸透膜装置5に供給する。この酸性の熱水での殺菌を10~60分間継続し、逆浸透膜装置5などを徐々に降温し、殺菌を終了する。殺菌終了後、純水製造装置1は、必要に応じて純水などで全体をすすぎ洗浄し、その後、原水タンク2から原水を送出し、逆浸透膜装置5などで原水を処理して純水を製造する。【選択図】 図1
