| 摘要 |
PROBLEM TO BE SOLVED: To provide a washing method enabling to easily and surely remove contamination substance collected with a spiral type membrane element. SOLUTION: The spiral type membrane element 1 is constituted by covering a spiral-shaped membrane element 1a consisting of a plurality of independent or continuous envelope-like membranes wound on the outer peripheral surface of a water collection tube 2 via raw water spacers 4 with a separation membrane 9, and further covering the resultant assembly with an outer peripheral part flow path material 5 consisting of a plurality of wires 61, 62. In washing, transmission water 52 containing chemicals having a peeling action against the contamination substance is introduced from the open end of the water collection tube 2, and the transmission water 52 discharged from the outer peripheral part surface of the water collection tube 2 is discharged from at least the outer peripheral part side of the spiral type membrane element 1, and also the raw water 51 is made to flow in the axis direction along the outer peripheral part of the spiral type membrane element 1.
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