NOMURA MICRO SCIENCE CO., LTD.

A pure water production device and method are capable of suppressing scale clogging in a reverse osmosis membrane, stably and efficiently producing pure water over a long period. The pure water production method obtains pure water by passing raw water sequentially through multiple reverse osmosis membranes. An alkali treatment step passes alkaline water through one stage, and an acid treatment step passes acidic water through another, executed in a predetermined order. A first treatment period uses a first reverse osmosis membrane for the alkali treatment step and a second for the acid treatment step, while a second treatment period swaps their roles. These periods repeat at a predetermined interval, with the first and second reverse osmosis membranes swapped.

A liquid circulating system has: a circulation path having a supply pipe that supplies liquid within a tank via plural treatment sections to a point of use, and a return pipe that returns liquid from the point of use to the tank; a first pump provided at the supply pipe in the midst of the plural treatment sections; a pressure detecting section provided at the return pipe; a regulating valve provided at the return pipe at a downstream side of the pressure detecting section, and regulating pressure of an interior of the return pipe in accordance with pressure detected by the pressure detecting section; a flow rate detecting section provided at the supply pipe between the point of use and a treatment section that is furthest downstream, and detecting a flow rate of liquid at an interior of the supply pipe; and a first pump controlling section that, in accordance with the flow rate detected by the flow rate detecting section, controls the first pump such that liquid flowing in the supply pipe becomes a predetermined flow rate.

A production method for water for pure water includes adding polyaluminum chloride to raw water to produce first treated water, and filtering the first treated water in two or more stages including filtering with a filtration membrane device in a preceding stage to produce first concentrated water, and filtering the first concentrated water with a filtration membrane device in a subsequent stage. The water for pure water is produced as permeated water produced by the filtering in the two or more stages.

An ultrapure water production system to produce an ultrapure water, includes a pre-treatment unit 2 ; a primary pure water production unit 3 ; a secondary pure water production unit 4 ; a storage unit 5 provided to precede the pre-treatment unit 2 or between the pre-treatment unit 2 and the primary pure water production unit 3 , the storage unit 5 being capable of storing raw water or treatable water; a recovery treatment unit 6 to remove impurities mixed in a used ultrapure water obtained after use of the ultrapure water and containing hydrogen peroxide with passing a part or the whole of the hydrogen peroxide therethrough, to make a recovered water; and a circulator 7 to circulate the recovered water obtained from the recovery treatment unit 6 to feed the recovered water back to the storage unit 5.

Provided is a stripping method capable of stripping a resist while suppressing the time and cost of processing required for stripping, while giving sufficient consideration to the load on the environment. The resist stripping method is a method for stripping a resist film-formed on a substrate, including: a pretreatment step of exposing the resist to a heated steam in a predetermined temperature range for a predetermined time; and a stripping step of stripping the resist exposed to the heated steam in the pretreatment step by using a resist stripping liquid, wherein the predetermined temperature range and the predetermined time are set according to the resist.

In the method for producing ultrapure water including filtration through a filtration membrane, the filtration membrane is one or more selected from an UF, a MF and an ion exchange membrane, and the filtration is performed under conditions satisfying both (1) and (2). (1) A permeate water flux at the time of filtration is within a range from equal to or more than 0.5 times to equal to or less than 2.0 times of an optimum permeate water flux determined according to intermembrane differential pressure/permeate water flux in the filtration membrane. (2) A water recovery rate in the filtration is equal to or more than 50% and less than 80%.

A production method for water for pure water includes adding polyaluminum chloride to raw water to produce first treated water, and filtering the first treated water in two or more stages including filtering with a filtration membrane device in a preceding stage to produce first concentrated water, and filtering the first concentrated water with a filtration membrane device in a subsequent stage. The water for pure water is produced as permeated water produced by the filtering in the two or more stages.

A method and apparatus for producing water for pure water, the method and apparatus capable of efficiently adding agents to water to be supplied to a reverse osmosis membrane. The method for producing water for pure water includes: obtaining first treated water by adding a polyaluminum chloride to raw water containing free chlorine; obtaining second treated water by adding a reducing agent containing sodium disulfite as an active ingredient to the first treated water; and treating the second treated water with a reverse osmosis membrane.

A desalination apparatus 12 (liquid treatment apparatus) includes a first water treatment unit 26 (liquid treatment unit) that includes a reverse osmosis membrane and in which a treated liquid is separated into a permeate that permeates the reverse osmosis membrane and a concentrate other than the permeate, a water recovery unit 28 (liquid recovery unit) that includes a reverse osmosis membrane and in which the concentrate is separated into a recovered liquid that permeates the reverse osmosis membrane and a waste liquid other than the recovered liquid, and a pressure increasing means that increases a liquid pressure of the concentrate, such that a state capable of separating into the recovered liquid and the waste liquid in the liquid recovery unit continues, and that directly feeds the concentrate from the liquid treatment unit to the liquid recovery unit.

An electrode water recovery method is an electrode water recovery method for removing hydrogen gas from electrode water generated by passage of water to be treated through a cathode chamber in an electric deionization treatment and recovering the electrode water in an ultrapure water production step, in which the electrode water is sprayed onto a filling material with which a scrubber is filled, an inert gas is supplied from below the filling material to react with the hydrogen gas in the electrode water, a treated gas generated by the reaction is exhausted from an exhaust port above the filling material, and treated water from which the hydrogen gas has been removed is recovered.