An ultrapure water (UPW) production facility includes a polisher filled with an ion exchange resin, an inflow line, an inflow valve connected to the inflow line and upstream of the polisher, an outflow line, an outflow valve connected to the outflow line and downstream of the polisher, a first drain line connected to the polisher, a first drain valve connected to the first drain line and downstream of the polisher, a second drain line branched from the outflow line, a second drain valve connected to the second drain line, a discharge line branched from the second drain line, a discharge valve connected to the discharge line, wherein the inflow valve, the outflow valve, the first drain valve, the second drain valve, and the outflow valve are automatic valves.

A metal-chelating resin includes (a) a compound represented by Formula (I): ##STR00001##
or a stereoisomeric form thereof or a salt thereof, wherein R.sup.1, R.sup.2, R.sup.3, R.sup.4, R.sup.a, R.sup.b, R.sup.c and R.sup.d are as defined herein; and (b) an organic polymer resin having at least one complementary reactive functional group covalently linked with at least one linking group of the compound represented by Formula (I).

Processing water regeneration equipment includes a waste liquid treatment apparatus that treats waste liquid discharged from a processing apparatus for processing a workpiece by use of processing water, and a fuel cell apparatus that causes a chemical reaction between hydrogen and oxygen to produce electricity and water. The waste liquid treatment apparatus includes a positive electrode and a negative electrode disposed in a tank for reserving the waste liquid, and a hydrogen production unit that supplies electric power to the positive electrode and the negative electrode to produce hydrogen. The fuel cell apparatus causes a chemical reaction between the hydrogen produced by the hydrogen production unit and oxygen in the air to produce electricity and water, and the electricity and water thus produced are utilized in the processing apparatus.

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.

In a primary pure water device, an electric deionization device communicated with a water supply pump is provided with a DC power supply, and desalted water from the electric deionization device can be supplied to a sub-tank. The sub-tank is provided with a level switch. In addition, while a control valve and a flow meter are provided in a flow path for the desalted water from the electric deionization device, a control valve and a flow meter are also provided in a flow path for concentrated water from the electric deionization device. The measurement data of the level switch and the flow meters can be transmitted to a control device, which can control the water supply pump and the control valves.