| 摘要 |
<p>Provided is a method for cleaning a membrane module provided with a microfiltration membrane and/or an ultrafiltration membrane, and which is used to membrane-filter untreated water to obtain membrane-filtered water. Therein, in order to effectively clean a membrane module while minimizing drops in water recovery rates and chemical costs, and preventing leakages and retention of post-treatment chemical liquids to the secondary side of the membrane module, a chemical diffusion step is performed, in which chemical-containing water is supplied to the primary side of the membrane module, and the chemical is diffused from the primary side to the secondary side of the membrane module. This is followed by a backwash step in which water is backwashed from the secondary side of to the primary side of the membrane module. During the chemical diffusion step, the implementation time for the chemical diffusion step is controlled on the basis of the concentration of the chemical diffused to the secondary side of the membrane module.</p> |
