Abstract: An ultrapure water production system that has a simplified configuration and that can efficiently remove fine particles that are contained in ultrapure water is provided. Ultrapure water production system has ultrapure water supply line that is connected to point of use and that supplies ultrapure water to point of use; return line that returns the ultrapure water that has not been used at point of use to ultrapure water supply line; and at least one ion exchange apparatus that is provided on ultrapure water supply line. Space velocity of water to be treated that flows in final-stage ion exchange apparatus is 170 (1/hr) or more, and wherein final-stage ion exchange apparatus is an ion exchange apparatus that is closest to point of use from among at least one ion exchange apparatus.

Abstract: An apparatus for producing ultrapure water: first ultrafiltration membrane that is connected to point of use and that supplies ultrapure water to point of use; first concentrated water return line that returns concentrated water of first ultrafiltration membrane to an upstream side of first ultrafiltration membrane; pressure gauge that measures pressure at an outlet of first ultrafiltration membrane; and means for adjusting flow rate of the concentrated water (first valve). Means for adjusting the flow rate of the concentrated water can be operated such that when the flow rate of the concentrated water is changed, a change in the pressure at the outlet of first ultrafiltration membrane that is measured by pressure gauge is kept within a predetermined range.

Abstract: A water quality management method for performing at least one of a quantitative analysis and a qualitative analysis of fine particles contained in water to be analyzed that includes connecting a filtration device provided with a fine particle capturing membrane for capturing fine particles to a flow pipe through which the water to be analyzed flows, allowing the water to be analyzed to flow from the flow pipe and through the fine particle capturing membrane attached to the filtration device for a predetermined period of time to capture fine particles contained in the water to be analyzed to form a fine particle capturing membrane sample, and performing at least one of a quantitative analysis and a qualitative analysis of the fine particle capturing membrane sample of a target water flow period at an arbitrary timing.

Abstract: Fine particles that are contained in ultrapure water supplied to a point of use is further reduced. Ultrapure water production system has ultrapure water supply line that is connected to point of uses, wherein ultrapure water flows through ultrapure water supply line; and first ion exchange apparatus, membrane filtration apparatus and second ion exchange apparatus that are arranged in series on ultrapure water supply line. Membrane filtration apparatus is arranged between first ion exchange apparatus and second ion exchange apparatus. At least a part of the ultrapure water that flows out from membrane filtration apparatus is treated by second ion exchange apparatus before the at least a part of the ultrapure water is supplied to point of uses.

Abstract: The level of cleanliness of a hollow fiber membrane device is evaluated before it is installed in an ultrapure water production system. A method of evaluating the level of cleanliness of the hollow fiber membrane device includes capturing fine particles in permeating water by means of a first filter membrane, wherein the permeating water is ultrapure water that permeates through the hollow fiber membrane device before the hollow fiber membrane device is installed in an ultrapure water production system; and analyzing the fine particles that are captured by the filter membrane.

Abstract: A centrifugal filtration device is provided. The centrifugal filtration device has filtration membrane that filtrates liquid; cartridge that supports filtration membrane and that forms liquid chamber together with filtration membrane, wherein liquid chamber holds the liquid therein; and rotating member that rotates around rotation center and that supports cartridge such that filtration membrane is positioned outward of liquid chamber with respect to rotation center. Rotating member has a path that is connected to liquid chamber, and at least a part of a liquid contact part of the path that is in contact with the liquid is formed of titanium or a titanium alloy.

Abstract: The level of cleanliness of a hollow fiber membrane device is evaluated before it is installed in an ultrapure water production system. A method of evaluating the level of cleanliness of the hollow fiber membrane device includes capturing fine particles in permeating water by means of a first filter membrane, wherein the permeating water is ultrapure water that permeates through the hollow fiber membrane device before the hollow fiber membrane device is installed in an ultrapure water production system; and analyzing the fine particles that are captured by the filter membrane.

Abstract: Provided is a method of washing a hollow fiber membrane device which can efficiently remove fine particles while limiting the impact of an ultrapure water production system on the starting time. The method of washing a hollow fiber membrane device includes washing a hollow fiber membrane device with an alkaline aqueous solution before the hollow fiber membrane device is installed in an ultrapure water production system. The hollow fiber membrane device is washed by means of a washing device that is different from the ultrapure water production system.

Abstract: A centrifugal filtration device is provided. The centrifugal filtration device has filtration membrane that filtrates liquid; cartridge that supports filtration membrane and that forms liquid chamber together with filtration membrane, wherein liquid chamber holds the liquid therein; and rotating member that rotates around rotation center and that supports cartridge such that filtration membrane is positioned outward of liquid chamber with respect to rotation center. Rotating member has a path that is connected to liquid chamber, and at least a part of a liquid contact part of the path that is in contact with the liquid is formed of titanium or a titanium alloy.

Abstract: An ultrapure water production apparatus (1) includes an ultrafiltration membrane device (10). The ultrafiltration membrane device (10) includes a plurality of ultrafiltration membranes (11, 12) that are connected in series. The plurality of ultrafiltration membranes (11, 12) include a first ultrafiltration membrane (11) and a second ultrafiltration membrane (12) located farthest downstream among the plurality of ultrafiltration membranes (11, 12), the second ultrafiltration membrane (12) having filtration properties that are different from filtration properties of the first ultrafiltration membrane (11).

Abstract: A particle capture filtration film with communication pores formed by anode oxidization of an aluminum material includes a small pore diameter part having communication pores formed to open to one surface of the filtration film, an intermediate pore part having communication pores to which the communication pores of the small pore diameter part are connected and that have a larger diameter than a diameter of the communication pores in the small pore diameter part, and a large pore diameter part having communication pores to which the communication pores of the intermediate pore part are connected and which have a larger diameter than a diameter of the communication pores in the intermediate pore part and are formed to open to the other surface of the filtration film.