Method for supply of constant-concentration ozonated water

1. A method for the supply of a constant-concentration ozonated water, comprising

employing a unit for producing ozonated water by contact between an ozone-containing gas and water and a system for using the ozonated water produced by the unit at a place separated therefrom, said unit having an inlet for non-ozonated feed water, an ozonated water inlet, and an ozonated water outlet;

interposing an ozonated water circulating line between the ozonated water inlet and the ozonated water outlet, the circulating line extending extending to a neighborhood of the place for using the ozonated water;

causing an interior of the circulating line to circulate the ozonated water so that a flow rate may be constantly fixed at the ozonated water outlet of the ozonated water producing unit;

monitoring an ozone concentration of the ozonated water in the neighborhood of the ozonated water outlet;

adjusting an amount of the ozone containing gas supplied to the ozonated water producing unit and/or a concentration of the ozone containing gas based on results of the monitoring;

further monitoring an amount of the ozonated water used at the place for using the ozonated water; and

controlling an amount of the ozonated water to be produced based on the results of monitoring of the amount of ozonated water used.

2. A method according to claim 1 , wherein the amount of the ozonated water to be produced is controlled by monitoring in the ozonated water circulating line the amount of the ozonated water used at the place for using the ozonated water.

3. A method according to claim 1 , comprising producing ozonated water in the ozonated water producing unit by dissolving ozone gas in water, creating an ozone concentration gradient in the ozonated water producing unit, said gradient located between the inlet of non-ozonated feed water and the ozonated water outlets, and supplying the ozonated water returned through the ozonated water circulating line to the ozonated water inlet at a location in the unit where the concentration gradient exists, this location positioned at or after the inlet of non-ozonated feed water.

4. A method according to claim 3 , wherein the ozonated water producing unit utilizes an absorption column.

5. The method of claim 3 wherein the ozonated water returned to the ozonated water producing unit is supplied to a location within the concentration gradient wherein the concentrations of ozone in the ozonated water being returned and water being ozonated are approximately the same.

6. A method according to claim 1 , comprising treating semiconductors with said constant-concentration ozonated water.

7. A method according to claim 1 , wherein the ozonated water produced and supplied by the ozonated water producing unit has a concentration of not less than 10 ppm.

8. A method for the supply of a constant-concentration ozonated water comprising

employing a unit for produced ozonated water by contact between an ozone-containing gas and water and a system for using the ozonated water produced by the unit at a place separated therefrom, said unit having an inlet for non-ozonated feed water, an ozonated water inlet, and an ozonated water outlet;

disposing a storage tank in the ozonated water producing unit or between the ozonated water producing unit and the place for using the ozonated water;

interposing an ozonated water circulating line between the ozonated water inlet and the ozonated water outlet, said line extending to a neighborhood of the place for using the ozonated water;

causing an interior of the circulating line to circulate the ozonated water so that a flow rate may be constantly fixed at said ozonated water outlet of the ozonated water producing unit;

monitoring an ozone concentration of the ozonated water in a neighborhood of the ozonated water outlet;

adjusting an amount of the ozone containing gas supplied to the ozonated water producing unit and/or a concentration of the ozone containing gas based on results of the monitoring;

whereby the storage tank reduces fluctuations of the load placed on the ozonated water producing unit.

9. A method according to claim 8 , wherein the amount of the ozonated water to be produced is controlled by monitoring in the ozonated water circulating line the amount of the ozonated water used at the place for using the ozonated water.

10. A method according to claim 8 , comprising producing ozonated water in the ozonated water producing unit by dissolving ozone gas in water, creating an ozone concentration gradient in the ozonated water producing unit, said gradient located between the inlet of non-ozonated feed water and the ozonated water outlets, and supplying the ozonated water returned through the ozonated water circulating line to the ozonated water inlet at a location in the unit where the concentration gradient exists, this location positioned at or after the inlet of non-ozonated feed water.

11. A method according to claim 10 , wherein the ozonated water producing unit utilizes an absorption column.

12. The method of claim 10 wherein the ozonated water returned to the ozonated water producing unit is supplied to a location within the concentration gradient wherein the concentrations of ozone in the ozonated water being returned and water being ozonated are approximately the same.

13. A method according to claim 8 , comprising treating semiconductors with said constant-concentration ozonated water.

14. A method according to claim 8 , wherein the ozonated water produced and supplied by the producing unit has a concentration of not less than 10 ppm/ozonated water.