JP2903591B2 - Prevention of biological adhesion - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method for preventing the adhesion of organisms, and more particularly to a method for irradiating seawater with ultraviolet rays to prevent the adhesion of adherent organisms. The present invention relates to a method for preventing living organisms from adhering to a living body by reducing the amount of electric power for an ultraviolet lamp by adjusting the amount of ultraviolet irradiation according to the type.

[Prior art] In a system that uses a large amount of seawater as cooling water or the like,
The fouling organisms in seawater may adhere to facilities such as piping systems, heat exchangers, pumps, etc., and cause serious obstacles. Conventionally, as a method for preventing such damage due to adherent organisms, an ultraviolet irradiation method has been put to practical use as an extremely effective method since it can remove adherent organisms without causing environmental pollution or the like. I have. For example, Japanese Patent Application Laid-Open No. 50-9241 proposes a seawater treatment apparatus using ultraviolet light, and the amount of ultraviolet light required to kill these larvae for the purpose of preventing the adhesion of adherent organisms such as barnacles. It is stated that 50 mW · sec / cm ² is sufficient.

By the way, large adherent organisms such as barnacles float in water as zooplankton before attaching. This is called a larva, and the larva attaches to the walls of various facilities and transforms,
For the first time it takes the form of a parent. Many of these floating larvae go through several stages of metamorphosis. For example, in barnacles, the initial stage is called nauplius. Called Cypris.

[Problems to be Solved by the Invention] Japanese Patent Application Laid-Open No. 50-9241 describes that the irradiation amount of ultraviolet light necessary to kill larvae is sufficient at 50 mW · sec / cm ² , Is not enough for barnacle cypris larvae at 50 mW · sec / cm ² . That is, according to our studies, the in cypris larvae barnacle mortality is required ultraviolet irradiation dose of 12600mW · sec / cm ^2,
In addition, the irradiation of 420 mW · sec / cm ² of ultraviolet rays is required for the death of nauplius larvae.

Accordingly, the conventional ultraviolet irradiation method, for example, the barnacle larvae by mortality in order to reliably prevent the adhesion is considered that it is necessary to perform 12600mW · sec / cm ² or more ultraviolet irradiation, ultraviolet ray lamps The disadvantage is that the power costs are considerably high.

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and provides a method for preventing organisms from adhering in a method for preventing organisms from adhering by an ultraviolet irradiation method, which reduces power consumption for an ultraviolet lamp and enables efficient treatment. The purpose is to do.

[Means for Solving the Problems] The method for preventing adhesion of organisms according to the present invention is a method of irradiating seawater with ultraviolet rays to prevent the adhesion of adherent organisms. the amount of ultraviolet irradiation in order to prevent transformation and 2520mW · sec / cm ² or more, if only the nauplii is observed, 45 mW · sec / cm
² or more.

The present inventors have made the following findings as a result of intensive studies to minimize the amount of ultraviolet irradiation and to reduce power consumption for ultraviolet lamps.

As described above, large-sized adherent fouling organisms that give adhesion impairment go through the larva (zooplankton) stage in the initial stage of their development, become parents by repeating metamorphosis, and cause adhesion impairment. Therefore, it is not necessary to kill the larvae for the prevention of adhesion, and the adhesion can be prevented if the larva is not transformed. Then
The UV dose required to prevent metamorphosis is much lower than the dose required to kill. For example, in the cypris larvae of barnacles, the irradiance of 12600 mW · sec / cm ² is required for the death, but the irradiation of 2520 mW · sec / cm ² is sufficient to prevent metamorphosis. If the metamorphosis is inhibited, it will not be possible to grow into the parent shell, and the adhesion can be prevented. Also,
420 mW for mortality of barnacle nauplii larvae
-An ultraviolet irradiation dose of sec / cm ² is required, but an irradiation dose of 45 mW · sec / cm ² is sufficient to prevent transformation. If the metamorphosis of the nauplii larva is also prevented, the cypris larva and even the parent clam cannot be grown, and the attachment can be prevented.

For this reason, by setting the amount of ultraviolet irradiation not to the required amount of larval mortality but to the required amount of transformation inhibition, it is possible to greatly reduce the required power amount and to efficiently prevent adhesion.

Moreover, even the larvae of the same species have different resistance to ultraviolet rays depending on the step (growth stage). That is, as described above, but ultraviolet irradiation amount necessary for the transformation blocking of barnacles cyprids larvae is 2520mW · sec / cm ^2, may be 45mW · sec / cm ² in the nauplii. For this reason, the most efficient prevention of adhesion can be achieved by irradiating the larva with ultraviolet rays necessary for inhibiting its transformation according to the growth stage of the larva.

The present invention has been achieved based on such findings.

According to the method of the present invention, in order to prevent the adhesion of barnacles, when Cypris larvae are observed in seawater, the ultraviolet irradiation dose is set to 2520 mWsec / cm ² or more, and when only Nauplius larvae are observed, , 45 mW · sec / cm ² or more, where the growth stage of the larva can be easily known by observation with a stereoscopic microscope or the like. In addition, irradiation of ultraviolet rays
It can be easily performed by a normal ultraviolet irradiation device equipped with an ultraviolet lamp.

As previously described, the ultraviolet irradiation amount required for transformation blocking of barnacle larvae is cyprids: 2520mW · sec / cm ² nauplii: a 45mW · sec / cm ^2. Therefore, if the 45mW · sec / cm ² or more only nauplii is observed, for example 50~60mW · sec / cm ²
The process may be performed. On the other hand, if the cypris larvae is observed, 2520mW · sec / cm ² or more, for example 2600~2700mW
-Processing may be performed at sec / cm ² .

Here, the unit of mV · sec / cm ^{2 of the} amount of ultraviolet irradiation is the amount of irradiation with respect to the area of the flow of the seawater of interest, and is, for example, 1 m / s (that is, 1 t / s) in a channel having a cross section of 1 × 1 m ^2. 10mW · sec using ultraviolet light with illuminance of 1mW / cm ^{2 in} the area where seawater is flowing
In order to give an ultraviolet irradiation amount of / cm ² , irradiation is performed by attaching an ultraviolet lamp over a flow path for 10 sec, that is, a length of 10 m.

The method of the present invention is an ultraviolet irradiation device, a stereomicroscope,
It is also possible to perform the observation automatically by processing the observation data and using a controller that adjusts the irradiation amount of the ultraviolet irradiation device based on the data.

[Operation] In a system in which the application of the present invention takes a long time from taking water to discharging it, such as a seawater pumped storage power plant, nauplii larvae before the epidemic stage are also irradiated. There is a need. That is, nauplii larvae are transformed in the plant to become cypris and cause adhesion failure, so that nauplius also needs to be irradiated. Therefore, by observing the larvae in the incoming seawater, for example, when barnacles are the main fouling-adhering organisms, no cypris larvae appear, and in the case of only nauplii larvae, it is necessary to reduce the amount of ultraviolet irradiation to prevent metamorphosis. Quantity
45 mW · sec / cm ² or more. Then, when cypris larvae are observed, the amount of ultraviolet irradiation is increased to the required amount for inhibiting the transformation, that is, 2520 mW · sec / cm ² . Thereafter, when no cypris larvae are observed and only nauplii larvae are present, the ultraviolet irradiation dose is again reduced to 45 mW · sec / cm ² .

In this way, the type of larva appearing and its growth stage are observed, and depending on the situation, the amount of ultraviolet irradiation is adjusted to the amount of inhibition of the larva metamorphosis, whereby the larva is killed, Compared with the method of irradiating with the same irradiation amount, it is possible to reliably and efficiently prevent the attachment of organisms with a significantly smaller amount of electric power for the ultraviolet lamp.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples.

Example 1 The irradiation apparatus shown in FIGS. 1 and 2 was prepared, and an ultraviolet irradiation experiment was performed according to the following method.

FIGS. 1 and 2 are configuration diagrams showing an irradiation device for 1700 μW / cm ² and an irradiation device for 3000 to 7000 μW / cm ² , respectively, wherein 1 is a 10 W lamp, 2 is a 15 W lamp, and 3 is a 30 W lamp. It is. Reference numeral 10 denotes a petri dish. 11 is a stand, 12
Is a petri dish mounting table, 13 is a stainless steel table, 14 is a wooden cover, and 15 is an aluminum foil. The UV lamp used was 10
W (made by Toshiba), 15W (made by Matsushita Electric), 30W (made by Chiyoda Kosan), UV illuminance is TOPCON UV intensity meter UVA-25
It was measured by type 4. Prior to the exposure of the larva to ultraviolet light, the temporal change in the ultraviolet illuminance of the ultraviolet irradiation device was examined. The ultraviolet illuminance was stabilized about 2 minutes after the switch was turned on. Therefore, in all the subsequent experiments, the exposure was started at least 2 minutes after the switch was turned on.

Experimental method UV illuminance was 1700 μW / cm ^{2 to} 7000 μW / cm ² and irradiation time was
The larvae were placed in a petri dish (Pyrex glass petri dish with a diameter of 5 cm) together with 15 ml of natural seawater (water depth 1 cm) for 15 seconds to 30 minutes, and irradiated from the air. The water temperature was set around the water temperature of the field at the time of larval collection (16 to 20 ° C.), and all experiments were performed in a still water state.

 The samples used for the experiment are No. 1 and No. 2 below.

Experimental result As a result of the experiment, 45 mWsec /
transformation of up to cypris the cm ² on the border is impossible, and for cypris larvae has been proven to be the impossible transformation up to the parent to the boundary of the 2520mW · sec / cm ^2.

[Effects of the Invention] As described in detail above, according to the method for preventing organisms from adhering to the organism, the amount of ultraviolet irradiation in the ultraviolet irradiation method can be minimized, and the electric power can be reliably and efficiently obtained with low power cost. It is possible to carry out the treatment for preventing the attachment of living things at low cost.

[Brief description of the drawings]

1 and 2 are configuration diagrams of the irradiation device used in the first embodiment, respectively. 1 ... 10W lamp, 2 ... 15W lamp, 3 ... 30W lamp, 10 ... Petri dish.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Shogo Nagayama 6-15-1, Ginza, Chuo-ku, Tokyo Inside Power Supply Development Co., Ltd. (72) Inventor Hiroshichi Suzuki 3-14-5 Tamagawa, Setagaya-ku, Tokyo New Inside Japan Meteorological Ocean Corporation (72) Kazuyuki Kobayashi 3-14-5 Tamagawa, Setagaya-ku, Tokyo New Japan Meteorological Ocean Corporation (72) Masanori Kawabe 3-4-2 Nishishinjuku, Shinjuku-ku, Tokyo No. Kurita Kogyo Co., Ltd. (56) References JP-A-50-9241 (JP, A) JP-A-2-160009 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) C02F 1/32

Claims (1)

(57) [Claims] 1. A method of irradiating seawater with ultraviolet rays to prevent the adherent organisms from adhering, wherein when the cypris larvae are observed in the seawater, the ultraviolet irradiation dose is 2520 mW · sec / cm ² or more, and only the nopris larvae are exposed. 45mWsec / if observed
cm ² or more, a method for preventing organisms from adhering.