Prevention method of aquatic attaching fouling organisms and its apparatus

A prevention and control method of aquatic fouling organisms, said fouling organisms having attaching portions, comprising the steps of

• a) covering the surface of a submerged structure with a multilayer body in which said multilayer body is composed of a plurality of mutually insulated metallic plates, said plates being made of one member selected from the group consisting of iron, magnesium, aluminum and alloys thereof, through an insulating material and a cushion material to form a metallic cover;
• b) connecting said metallic cover to the positive pole of a DC power supply whereby said metallic plate functions as the anode;
• said anode having a surface;
• c) connecting said submerged structure to the negative pole of said DC power supply to use it as a cathode and to form an electric circuit;
• and
• d) supplying a current with a current density of not more than 500 mA/m.sup.2 between said cathode and said anode either continuously or intermittently at an interval of 10 seconds to 60 minutes so as to control or prevent attachment of said aquatic fouling organisms to the surface of said metallic plate functioning as the anode by dissolving and activating the surface of said metallic plate.

A prevention and control method of aquatic fouling organisms, said fouling organism having attaching portions, comprising the step of

• a) covering the surface of an intake facility other than its bottom surface with a multilayer body in which said multilayer body is composed of a plurality of mutually insulated metallic plates, said plates being made of one member selected from the group consisting of iron, magnesium, aluminum and alloys thereof through an insulating material and a cushion material to form a metallic cover;
• b) connecting said metallic cover to the positive pole of a DC power supply whereby said metallic cover functions as the anode;
• c) disposing iron or an iron alloy material on said bottom surface of said intake facility and connecting it to the negative pole of the DC supply whereby said iron or iron alloy material functions as the cathode and an electric circuit is formed;
• d) supplying a current with a current density of not more than 500 mA/m.sup.2 between said cathode and said anode either continuously or intermittently at an interval of 10 seconds to 60 minutes so that the surface of said metal constituting said metallic cover which functions as the anode is dissolved and activated, and attachment of said aquatic attaching fouling organisms to the surface of said metallic cover is controlled or prevented.

A prevention apparatus against aquatic fouling organisms having attaching portions, comprising:

• a multilayer body fitted to the inner surface of an intake facility other than its bottom surface in which said multilayer body is composed of a plurality of mutually insulated metallic plates made of one member selected from the group consisting of iron, magnesium, aluminum and alloys thereof through an insulating material and a cushion material;
• an iron member or its alloy member disposed on such bottom surface of said intake facility;
• and
• a DC current supply capable of supplying a current between said metallic plates and said iron or said alloy member.