Liquid treatment apparatus and liquid treatment method

1. A liquid treatment apparatus comprising:

a nozzle having an orifice shape, generating cavitation bubbles due to boiling phenomenon in an area where pressure falls after passing through a most contracted portion of the orifice shape, in liquid to be treated; and

a discharger generating discharge plasma in a region where the cavitation bubbles are generated.

2. The liquid treatment apparatus according to claim 1 , further comprising a pressurization pump arranged on an upstream side of the nozzle to feed the liquid toward the nozzle.

3. The liquid treatment apparatus according to claim 1 , the discharger comprising electrodes arranged to interpose there between the region where the cavitation bubbles are generated.

4. The liquid treatment apparatus according to claim 3 , wherein the electrodes comprise either:

a combination of two among a line-shaped electrode, a rod-shaped electrode and a flat plate electrode, the combination including a combination of electrodes having the same shape, or

a combination of a line-shaped electrode or a rod-shaped electrode and a spiral-shaped electrode.

5. The liquid treatment apparatus according to claim 3 , further comprising a liquid conduit arranged on a downstream side of the nozzle,

wherein the electrodes comprise:

an electrode arranged on a periphery of a distal end portion of the nozzle; and

an opposed electrode disposed inside the liquid conduit.

6. The liquid treatment apparatus according to claim 3 , wherein protrusions are formed on a surface of the electrodes.

7. The liquid treatment apparatus according to claim 2 , wherein the pressurization pump comprises:

a motor;

a pump;

an insulating base on which the motor and the pump are arranged so as to be spaced away from each other; and

an insulating member through which a rotation of the motor is transmitted to the pump.

8. The liquid treatment apparatus according to claim 1 , wherein the pressurization pump comprises:

a power source; and

a high-voltage insulating transformer through which power is supplied from the power source.

9. The liquid treatment apparatus according to claim 1 , further comprising a pressure monitor device which, while the liquid is flowing, monitors a pressure on the upstream side of the nozzle or a pressure difference between the upstream side and a downstream side of the nozzle.

10. The liquid treatment apparatus according to claim 1 , further comprising a conductivity meter which monitors a conductivity of the liquid to be treated.

11. The liquid treatment apparatus according to claim 1 , further comprising injector which injects hydrogen peroxide into the liquid to be treated.

12. The liquid treatment apparatus according to claim 1 , further comprising irradiator which irradiates ultraviolet ray toward the region where the cavitation bubbles are generated.

13. The liquid treatment apparatus according to claim 1 , further comprising enricher arranged on an upstream side of the nozzle to enrich dissolved oxygen in the liquid.

14. A liquid treatment method comprising:

causing cavitation bubbles to be generated, due to boiling phenomenon in an area where pressure falls after passing through a most contracted portion of an orifice shape formed in nozzle, in liquid to be treated; and

generating discharge plasma in a region where the cavitation bubbles are generated.

15. A liquid treatment apparatus comprising:

means for generating cavitation bubbles to be generated, due to boiling phenomenon in an area where pressure falls after passing through a most contracted portion of an orifice shape formed in nozzle, in liquid to be treated; and

means for generating discharge plasma in a region where the cavitation bubbles are generated.