Abstract: An object of the present invention is to provide a porous hollow-fiber membrane having high strength while maintaining high pure-water permeation performance. A porous hollow-fiber membrane of the present invention is a porous hollow-fiber membrane including a fluororesin-based polymer, in which the porous hollow-fiber membrane has a columnar texture oriented in a longitudinal direction of the porous hollow-fiber membrane, and a molecular chain of the fluororesin-based polymer is oriented in the longitudinal direction of the porous hollow-fiber membrane.

Abstract: An object of the present invention is to provide a separation membrane having high mechanical strength and being less likely to cause clogging and capable of continuously maintaining high water permeation performance. The present invention relates to a separation membrane characterized in that the average diameter D1 of a spherical structure in a region within 10 ?m from a first surface in a separation membrane having a spherical structure layer formed of a thermoplastic resin and the average diameter D2 of a spherical structure in a region of 10 ?m to 20 ?m from a second surface satisfy the relational expression of D1>D2 and the average diameter D1 and the average diameter D3 of a spherical structure in a third region satisfy the relational expression of 1.10<D1/D3<4.00.

Abstract: A method for operating a reverse osmosis membrane filtration plant having a raw water intake unit, a pre-treatment unit, and a reverse osmosis membrane filtration unit having a reverse osmosis membrane module in this order, the method including: disposing a biofilm formation base material under conditions that reverse osmosis membrane supply water and/or reverse osmosis membrane non-permeated water in the reverse osmosis membrane filtration unit are/is flowed at a linear speed equal to a non-permeated water linear speed in the reverse osmosis membrane module of the reverse osmosis membrane filtration unit; evaluating a biofilm amount on the biofilm formation base material at a frequency of from once a day to once in six months; and controlling the method for operating a reverse osmosis membrane filtration plant based on results of the evaluation.

Abstract: The present invention is a water processing method comprising the steps of separating boron-containing water in a reverse osmosis membrane module to provide a permeated water and subjecting a part of the obtained permeated water to boron removal using an adsorbent, wherein the water subjected to the boron removal is mixed with the water not subjected to the boron removal of the permeated water to provide a mixed water. The present invention provides economic water processing method and apparatus that remove the boron from boron-containing water.

Abstract: The present invention is a water processing method comprising the steps of separating boron-containing water in a reverse osmosis membrane module to provide a permeated water and subjecting a part of the obtained permeated water to boron removal using an adsorbent, wherein the water subjected to the boron removal is mixed with the water not subjected to the boron removal of the permeated water to provide a mixed water. The present invention provides economic water processing method and apparatus that remove the boron from boron-containing water.

Abstract: A method and apparatus for desalinating water, especially sea water, having a plurality of membrane module units disposed at respective successive stages are disclosed. Permeated water from a first stage membrane module unit is supplied to a second stage membrane module unit to obtain permeated water. The apparatus contains at least first and second membrane module units at respective successive first and second stages for water permeation.