| 摘要 |
<p>In a method for cleaning a separation membrane module in which filtration is performed through a separation membrane after mixing and stirring raw water containing particles having hardness higher than that of the separation membrane with an inorganic flocculant, in order to efficiently reduce the abrasion of the membrane surfaces by the particles having higher hardness during air scrubbing and to suppress the cake filtration resistance derived from the flocculation flocks containing the particles having high hardness on the membrane surfaces at the time of successively performing a filtration step, thereby enabling stable operation at a low transmembrane pressure over a long period of time, (a) water on a membrane primary side in the separation membrane module is discharged outside the system after completion of the filtration; then (b) the membrane primary side in the separation membrane module is filled with water containing a chelating agent for a certain period of time; subsequently (c) the water containing the chelating agent on the membrane primary side in the separation membrane module is discharged outside the system; and then (d) backwashing discharge water in the separation membrane module is discharged while performing backwashing in which backwashing water is transferred from a membrane secondary side to the membrane primary side of the separation membrane module.</p> |
