JPH1146618A - Prevention of germination of harmful plankton cyst and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for safely, continuously and massively treating harmful plankton cysts present in ballast water for ships and sediments on the seabed so as to efficiently prevent their germination, and also to provide a device therefor. SOLUTION: This method comprises continuously passing seawater containing harmful plankton cysts through a treating zone with two or more pairs of electrodes arranged in series, and preventing germination of harmful plankton cysts by shocks by shocks provided by an electric current flowing between each pair of the electrodes. The device to be used for the above method is composed of a pipe 1 for treating seawater, a seawater-sucking pump 2 connected to one end of the pipe 1, two or more pairs of electrodes 3 arranged at constant intervals on the inner pipe wall, AC current source 4 which applies a voltage between each pair of the electrodes 3, and grounding wire 5 for the pipe 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for continuously and efficiently suppressing the germination of harmful plankton cysts present in ballast water and marine sediments of ships.

[0002]

2. Description of the Related Art Closed and polluted seawater in an inner bay contains:
There is harmful plankton for fish etc.
Plankton in this seawater becomes unsuitable for growth when the surrounding environmental conditions (eg, water temperature, light, nutrient concentration, etc.)
It is known that they form cysts and die themselves.
The cysts settle down and accumulate on the sea floor, but germinate again when environmental conditions improve. At this time, a large amount of germination at once,
What multiplied is a phenomenon called red tide, which causes fishery damage. Also, once the red tide plankton is generated, if the surrounding environmental conditions are no longer suitable for growth, it will again form a cyst and die itself. Then, such a cycle is repeated.

[0003] In the case of a ship, seawater is supplied into the tank as ballast water, but the seawater contains plankton, and there is no light in the tank and the environment is poor.
As mentioned above, plankton forms a cyst and dies itself. When a ship discharges ballast water at a foreign port of call after sailing, cysts are discharged at the same time, and the discharged cysts germinate due to improved environmental conditions. And since ships sail and call around the world, if the cyst is a harmful plankton cyst, the harmful plankton will spread all over the world.

The occurrence of red tide of harmful plankton due to the germination of such cysts, the drainage of ballast water at foreign ports of call of ships, and the pollution of water due to the global diffusion of harmful plankton due to water supply are major problems. Has become.

[0005] As a method for suppressing the germination of harmful plankton cysts, conventionally, a method such as a batch-type heat treatment, electric treatment, or chemical treatment is known. However, it is difficult to treat cysts existing in a large amount of seawater, such as ballast water of ships, or cysts distributed over a wide area, such as in sediments, by batch-type heat treatment or electric treatment. However, the method using chemical treatment has drawbacks such as concern about environmental pollution by the chemical used.

[0006]

Under such circumstances, the present invention safely and continuously treats a large amount of harmful plankton cysts and effectively kills the cysts before germination. It is an object of the present invention to provide a method and an apparatus capable of preventing the occurrence of red tide by cutting off the cycle and preventing the global spread of harmful plankton.

[0007]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies on a method for continuously preventing harmful plankton cysts from germinating. The inventor has found that the object can be achieved by repeatedly applying current while continuously passing seawater containing cysts, and based on this finding, the present invention has been accomplished.

That is, according to the present invention, while continuously passing seawater containing harmful plankton cysts through a treatment region in which a plurality of electrode pairs are arranged in series, electricity is supplied through each electrode to generate an electric shock. A method for preventing harmful plankton cyst germination, a seawater treatment pipe (1), a seawater suction pump (2) connected to one end of the pipe, and a plurality of electrode pairs (3) attached to the pipe side wall at regular intervals. , 3...), An AC power source (4, 4,...) For applying a voltage to each electrode pair, and a harmful plankton cyst germination prevention device comprising a pipe ground 5.

[0009]

Next, an example of an embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an explanatory side view showing an example of the apparatus of the present invention, and has a structure in which a seawater suction pump 2 is provided at one end of a seawater treatment pipe 1. A plurality of electrode pairs 3, 3... Are attached to the pipe 1 at regular intervals, and a voltage is applied to each of the electrode pairs from an AC power supply 4, 4,. The seawater is taken into the pipe 1 by the suction pump 2, moves along the arrow, and is supplied with AC power by the power supply pairs 3, 3,.
The harmful plankton cysts contained in the seawater are continuously subjected to an electric shock during this time, and their germination is suppressed.

The pipe 1 is made of a corrosion-resistant metal such as steel or a nickel alloy, or a synthetic resin such as polyvinyl chloride or polyolefin. The size is appropriately determined according to the purpose of use, but is usually selected within a range of 100 to 5000 mm and a length of 10 to 50 m. The length is desirably 20 m or more in consideration of the effect on fish near the drain outlet and electrical safety. The wall thickness of this pulp is not particularly limited as long as it can sufficiently withstand seawater, but is usually selected in the range of 5 to 30 mm.

The electrode pairs 3, 3...
Usually, they are mounted in series facing each other at intervals of 0 to 2000 mm, but the mounting positions can be further increased according to the desired processing capacity. This interval is appropriately increased or decreased according to the size of the pipe or the passing speed of seawater. Further, the electrode pairs 3, 3,... Are attached in a number necessary to provide an electric shock sufficient to suppress the germination of harmful plankton cysts in seawater. Usually, about 10 to 100 pairs are provided at opposing positions on the inner surface of the pipe. The electrodes are energized by the AC power supplies 4, 4,..., But when a voltage of 100 V is used, it is preferable that the energization be performed for at least 10 seconds while the seawater passes through the pipe.

In the present invention, in order to suppress the germination of harmful plankton cysts in sediments on the seabed, the above-described apparatus is installed on the seabed, and an alternating current is applied through the electrode pairs 3, 3,. The sediment is continuously introduced into the pump together with seawater by the seawater suction pump 2 connected to one end of the pipe 1. Thereby, the cysts in the sediment are sucked into the pipe 1 together with the sediment, and are subjected to an electric shock,
Its germination is suppressed. At this time, the pipe 1 is horizontally moved at any time on the seabed to treat harmful plankton cysts.

Next, when treating cysts in ballast water of a ship, the pipe 1 is connected to a ballast water absorption / drainage pipe, and the ballast water is drained while energizing through the electrode pairs 3, 3,. . In this manner, an electric shock is applied to the cysts in the ballast water passing through the pipe 1 to suppress germination.

[0014]

Next, the present invention will be described in more detail by way of examples.

EXAMPLE 26 electrode pairs with a distance between electrodes of 100 mm were attached to the center of a polyvinyl chloride tube having a diameter of 200 mm, a length of 20 m and a thickness of 3 mm at intervals of 300 mm by 26 pairs each.
A suction pump was connected to one end of the polyvinyl chloride tube.
The processing apparatus having such a structure is arranged substantially horizontally on a sediment containing harmful plankton cysts on the sea floor, and after the earth is brought into contact with the sea floor, an AC power supply of 100 V is applied to each electrode pair.
While applying the pressure, the suction pump was operated to pass the sediment and the seawater at a speed of 1 m per second. In this way,
A portion of the continuously treated water is collected and at 15 ° C.
Stored for months, no plankton occurred.
Also, for comparison, seawater without the above treatment was
When stored at ℃ for one month, a lot of plankton was generated and the seawater was colored reddish brown.

[0016]

According to the present invention, the germination of a large amount of harmful plankton cysts can be suppressed safely and efficiently continuously, water pollution such as red tide can be prevented, and ballasting of ships can be prevented. When applied to water absorption and drainage pipes, germination of cysts during ballast water drainage can be suppressed.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one example of the present invention.

[Explanation of symbols]

 1 Pipe 2 Seawater suction pump 3 Electrode pair 4 AC power supply 5 Earth

Claims (2)

[Claims] The present invention is characterized in that an electric shock is applied through each electrode while continuously passing seawater containing harmful plankton cyst to a treatment region in which a plurality of electrode pairs are arranged in series. Harmful plankton cyst germination prevention method. 2. A seawater treatment pipe (1), a seawater suction pump (2) connected to one end of the pipe, a plurality of electrode pairs (3, 3,...) Attached at regular intervals to the pipe side wall, and each electrode pair. A harmful plankton cyst germination prevention device comprising an AC power supply (4, 4...) For applying a voltage to and a pipe ground 5.