Patent ID: 8636904

Claim:
A water treatment method with (a) a hollow fiber membrane module or (b) a hollow fiber membrane unit comprising a plurality of the hollow fiber membrane modules, wherein the hollow fiber membrane module comprises sheet-form hollow fiber membranes ( 1 ) including hollow fiber membranes ( 1 ) having a non-porous layer; and an anchoring member ( 2 ), wherein an end of a side of a hollow fiber membrane opening of the sheet-form hollow fiber membrane ( 1 ) is fastened by the anchoring member ( 2 ) so that a plurality of the sheet-form hollow fiber membranes ( 1 ) are substantially parallel to each other while leaving the end open, an end face of the anchoring member ( 2 ) on a side where the hollow fiber membranes are exposed is substantially rectangular, and an end face of the anchoring member ( 2 ) on a side where the hollow fiber membranes open is substantially circular, wherein the anchoring member ( 2 ) has a substantially rectangular parallelepiped shape on a side where the hollow fiber membranes are exposed, the substantially rectangular parallelepiped shape has a longer side, and has a cylindrical section ( 4 ) having a substantially cylindrical shape on a side where the hollow fiber membranes open, (a) the hollow fiber membrane module or (b) the hollow fiber membrane unit satisfies the relationship 1.0 <W/D< 2.0, wherein W (mm) is a length of the longer side of the end face where the hollow fiber membrane is exposed to the rectangular parallelepiped section ( 3 ) and D (mm) is a diameter of the cylindrical section ( 4 ), and wherein the relationship 0.2≦L/D≦1 is satisfied where D (mm) is the diameter of the cylindrical section and L (mm) is a length of the cylindrical section in an axial direction thereof, said method comprising the steps of: attaching microorganisms to exterior surfaces of sheet-form hollow fiber membranes ( 1 ); supplying water to be treated to the exterior surfaces; supplying a gas consisting essentially of hydrogen into hollow portions of the sheet-form hollow fiber membranes ( 1 ) to purify the water to be treated; and discharging water that has permeated into the hollow portions of the sheet-form hollow fiber membranes.