JPH1042748A - Washing of fishing net - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an effective and simple method for washing a fishing net, capable of removing shells and pollutant organisms including these shells without damaging a fishing net at a low cost from a fishing net polluted by attachment and propagation of aquatic lives such as shells and algae which live in water. SOLUTION: A polluted fishing net is immersed in an aqueous solution of an inorganic acid and washed. Since calcareous shell in the shells is dissolved thereby, attached shell is removed from the fishing net and algae can physically readily be removed together with elimination of the attached shell from the fishing net. When the polluted fishing net is subjected to immersing treatment in an aqueous solution of high test bleaching powder or bleaching liquor or an aqueous solution of a hypochlorous acid salt and then, subjected to immersing treatment in an inorganic acid solution or reversely, the polluted fishing net is subjected to immersing treatment in the inorganic acid solution and successively, in an aqueous solution of high test bleaching powder, etc., the polluted fishing net can simply and completely be washed by only chemical without requiring much labor, because the calcareous shell is removed by action of the inorganic acid and algae are removed by action of high test bleaching powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for cleaning a fishing net,
In particular, the present invention relates to a method for cleaning fishing nets contaminated by adhesion and propagation of aquatic organisms such as shellfish and algae.

[0002]

2. Description of the Related Art Aquatic organisms such as shellfish (barnacles, mussels) and algae that inhabit underwater adhere to and propagate on fishing nets. For example, in a fish culture net, these aquatic organisms form a mesh. It becomes difficult to replace water because it closes,
There is a problem that it causes poor growth and death of fish due to pollution of water environment and lack of oxygen for fish habitation, causing serious damage to fish cultivation.In addition, if aquatic organisms attach to fish nets, However, there is a problem in that the handling of the net is hindered outside the water, and the attached shellfish, algae, and the like become resistant in the water, so that the fishing net is difficult to sink and the catching operation of the fish becomes difficult.

One of the conventional methods for solving these problems is to use a paint containing a tin compound such as tributyltin or triphenyltin as an antifouling agent on a fishing net in order to prevent aquatic organisms from contaminating the fishing net. Although applied, metals such as tin are harmful to the human body and pose a problem of environmental pollution to human society, and these antifouling agents are also expensive. In addition, even if these antifouling paints are used, it is necessary to wash the fishing net once every six months. As another one of the conventional methods, a method of removing algae from a fishing net contaminated by aquatic organisms using a detergent has been adopted. Examples of the detergent include a detergent obtained by adding a flocculant selected from sodium maleate, sodium polyacrylate, and sodium salt of CMC to hypochlorite (Japanese Patent Publication No. 2-28638) and chlorine dioxide as an active ingredient. (Japanese Patent Publication No. 59-32518) are known. These bleaching agents decolorize and whiten algae to facilitate physical removal, but are effective in removing attached shellfish. Therefore, it was not possible to sufficiently remove algae entangled with the attached shellfish. In this case, if the attached shellfish remains, algae are immediately entangled when the fishing net is used, and the problem remains that the fishing net is hard to sink in water due to the resistance due to the attached shellfish. In addition, due to the generation of microorganisms by the attached dead shellfish,
There was a problem of fish environmental pollution when fishing nets were used, and a bad smell when fishing nets were not used. Therefore, although the attached shellfish was physically removed from the fishing net by hand, it was not only troublesome but also often damaged the fishing net.

[0004]

Therefore, the present invention according to claim 1 of the present invention is to remove shellfish by chemicals from fishing nets contaminated by the attachment and propagation of aquatic organisms such as seaweed and shellfish living in water. The invention of claim 2 or 3 provides a method for cleaning a fishing net, which is effective and simple, can remove the fishing net without damaging it, and can easily easily remove attached seaweeds. The invention according to claim 4, wherein a method for cleaning a fishing net, which is effective and simple, can remove all the contaminating organisms including the shellfish by a chemical alone without human intervention, does not damage the fishing net, and is inexpensive, is provided. It is an object of the present invention to provide a method for cleaning a fishing net having a greater effect on shellfish removal in the inventions according to claims 1 to 3.

[0005]

Means for Solving the Problems In order to achieve the above object, as a result of intensive studies, the present invention has been completed. That is, the invention according to claim 1 of the present invention is a method for cleaning a fishing net with an aqueous solution of an inorganic acid. Here, examples of the inorganic acid include hydrochloric acid, sulfuric acid, nitric acid, and phosphoric acid. The water serving as the solvent may be either fresh water or seawater. The concentration range of the inorganic acid that can be used in the present invention is not particularly limited depending on use conditions, but is usually 1 to 20%, preferably 1 to 5%. If the concentration is lower than this range, the effect of removing shellfish is not sufficiently exerted, and if the concentration is higher than the upper limit, shellfish and the like are completely removed, which not only wastes drugs but also may damage the fishing net. By adopting such a configuration, the inorganic acid dissolves the calcareous shell of the shellfish, so that the shellfish firmly attached to the fishing net is separated from its base (partly dissolved as a whole) and removed, and only the shellfish is removed. The algae entangled in the shell are removed together with the shellfish. Algae entangled in both the shellfish and the fishing net and only in the fishing net are in a state where they can be physically easily removed. This is thought to be due to the fact that the inorganic acid dissolves the ash, which is a component of the algae, and weakens the physical strength of the algae, in addition to the reason that the attached shellfish is separated from the fishing net. As a result, the algae remaining on the fishing net can be relatively easily removed even by using a conventional physical method (such as spraying pressure water), and the fishing net can be reused. In this case, the action of the inorganic acid causes the shellfish to be spontaneously detached or physically easily detached, so that the removal of the entire contaminant does not require human labor as in the past, and is very simple. Moreover, it does not damage the fishing net.

According to a second aspect of the present invention, there is provided a method for cleaning a fishing net, comprising treating with an advanced bleaching powder, a bleaching solution or an aqueous solution of hypochlorite, and then treating with an aqueous solution of an inorganic acid. The invention according to claim 3 is a method for cleaning a fishing net, which comprises treating with an aqueous solution of an inorganic acid and then treating with an advanced bleaching powder, a bleaching solution or an aqueous solution of hypochlorite. The concentration of the highly bleached powder is usually 0.1 to 2%, preferably 0.2%.
~ 1%. The concentration of the bleaching solution and the hypochlorite is generally 0.07 to 2%, preferably 0.1 to 1%, as the effective chlorine concentration in the aqueous solution. If the concentration is lower than these ranges, the effect of removing algae and the like is not sufficiently exhibited, and if the concentration is higher than the upper limit, the algae and the like are almost completely removed, which not only wastes drugs but also may damage the fishing net. is there. When used in these concentration ranges, the drug does not harm the fishing net. In addition, it is not always necessary to use each of the advanced bleaching powder, the bleaching liquid and the hypochlorite alone, and they may be used in combination. By adopting such a configuration, not only the attached shellfish can be easily removed by the inorganic acid for the same reason as described above, but also the attached algae are decolorized and whitened by highly bleached flour and the like and withered by the action of the used chemical. And can be easily and completely removed by washing with water. However, as in the invention according to claim 2, when the inorganic acid is allowed to act after substantially removing the algae by treatment with highly bleached powder or the like, the inorganic acid may be actuated first as in the invention according to claim 3. In comparison, since the action of the inorganic acid on the shellfish is made more efficient, the removal of the attached shellfish becomes easier. After washing, the fishing net is almost odorless, with no algae or shellfish, and when colored with paint, becomes a new fishing net. In this case, calcareous shells such as shellfish are removed from the fishing net by inorganic acid treatment, and algae etc. are removed from the fishing net by the chemical action of these chemicals by treatment with advanced bleaching powder. It is simple, easy and complete and does not require any damage and does not damage the fishing net. Further, since these drugs are mass-market products and inexpensive, the cleaning cost is also low.

[0007] In the present invention, the inorganic acid is preferably hydrochloric acid as in the fourth aspect of the present invention. Hydrochloric acid is effective in dissolving the calcareous shell of shellfish such as barnacles (that is, calcium of shell constituents) more efficiently than other inorganic acids, and is effective in removing shells.

[0008]

Embodiments of the present invention will be described below. (1) Fishing nets contaminated by aquatic organisms (including ropes)
Is immersed in a 1 to 20% hydrochloric acid aqueous solution for 4 to 24 hours.
However, since a large shellfish attaches to the rope part,
For the removal, it is preferable to use hydrochloric acid having a relatively high concentration in the above concentration range. As a result, the calcareous shells of shellfish such as barnacles are dissolved, so that the attached shells are mainly removed from the roots of the fishing net (partly dissolved in their entirety). In this case, the seaweed entangled only in the shellfish is removed together with the shellfish, and the seaweed entangled in both the shellfish and the fishing net or only the fishing net is easily removed physically. As a result, the seaweed remaining in the fishing net can be relatively easily removed using a conventional physical method (such as spraying pressure water). Therefore, if the fishing net is taken out and washed with high-pressure water, the contaminants are completely removed from the fishing net, and the fishing net can be reused.

(2) A fishing net (including a rope portion) contaminated with aquatic organisms is put in a 0.2 to 1% aqueous solution of highly bleached powder in an amount of 4 to 2%.
Soak for 4 hours, then take out the fishing net and wash with water. As a result, the contaminants attached to the fishing net are bleached and whitened and die, and a considerable portion of the seaweed is removed, but most of the shellfish and a part of the seaweed entangled in the shell and the net remain attached to the fishing net. Next, it is immersed in a 1 to 20% hydrochloric acid aqueous solution for 4 to 24 hours. However, since a large shellfish adheres to the rope portion, it is preferable to use high-concentration hydrochloric acid in the above-mentioned concentration range for the removal. by this,
The ash in barnacles and other shellfish and ash in seaweed is dissolved, and contaminants are separated from fishing nets. Therefore, if the fishing net is taken out and washed, the pollutants are completely removed from the fishing net. Note that the same effect can be obtained by changing the order of the above treatments and performing a high bleaching treatment after the hydrochloric acid treatment.

[0010]

【Example】

Example 1 A unit amount of 100 g of a fishing net on which aquatic organisms adhered and propagated was cut out (about 20 cm × 20 cm, in which case the weight of a wet fishing net alone was about 10 g), and immersed in 1 liter of a 1% hydrochloric acid aqueous solution for 24 hours. Thereafter, the fishing net is taken out, washed, and the weight in a wet state (hereinafter, referred to as a wet weight) with attached water wiped off is measured. Subsequently, after standing for 24 hours (air drying), the type and degree of the attached matter and the odor were observed with the eyes and nose of the observer. As the hydrochloric acid, a commercially available 35% hydrochloric acid (specific gravity: 1.18) was used after being diluted to a predetermined concentration with water. Example 2 The same treatment as in Example 1 except that a 5% hydrochloric acid aqueous solution was used.
Observations were made. Example 3 The same treatment as in Example 1 except that a 5% aqueous sulfuric acid solution was used.
Observations were made. Example 4 First, a unit of 100 g of a fishing net on which aquatic organisms adhered and propagated was cut out (about 20 cm × 20 cm, in which case the wet weight of the fishing net alone was about 10 g), and a highly bleached powder containing 70% effective chlorine for food addition was added. After immersing for 24 hours in 3 liters of a 0.5% aqueous solution of a granule (manufactured by Nankai Chemical Industry Co., Ltd.) (hereinafter referred to as 70 high bleaching), the fishing net is taken out and washed with water. Next, the fishing net is immersed in 1 liter of a 10% aqueous hydrochloric acid solution for 24 hours, and then the fishing net is taken out, washed with water, and the attached water is wiped off to measure the wet weight. Then, leave for 24 hours (air drying)
Thereafter, the type and degree of the attached matter and the odor were observed with the eyes and nose of the observer. Example 5 The same treatment and observation as in Example 4 were carried out except that a 70% highly exposed 0.2% aqueous solution and a 1% hydrochloric acid aqueous solution were used. Example 6 First, a unit amount of 100 g of a fishing net on which aquatic organisms adhered and propagated was cut off (about 20 cm × 20 cm, in which case the wet weight of the fishing net alone was about 10 g), and a highly bleached powder containing 60% available chlorine for general use. Products (manufactured by Nankai Chemical Industry Co., Ltd.)
24 in 3 liters of 0.5% aqueous solution
After soaking for a time, the fishing net is taken out and washed with water. Next, the fishing net is immersed in 1 liter of a 1% hydrochloric acid aqueous solution for 24 hours, then the fishing net is taken out, washed with water, and the attached water is wiped off to measure the wet weight. Subsequently, after standing for 24 hours (air drying), the type and degree of the attached matter and the odor were observed with the eyes and nose of the observer. Example 7 First, a 100 g unit of a fishing net on which aquatic organisms adhered and propagated was cut out (about 20 cm × 20 cm, in which case the wet weight of the fishing net alone was about 10 g), and immersed in 1 liter of a 5% hydrochloric acid aqueous solution for 24 hours. After that, the fishing net is taken out and washed with water. Next, after immersing the fishing net in 3 liters of a 70% bleached 0.5% aqueous solution for 24 hours, the fishing net was taken out and washed,
The attached water is wiped off and the wet weight is measured. Subsequently, after standing for 24 hours (air drying), the type and degree of the attached matter and the odor were observed with the eyes and nose of the observer.

Comparative Example 1 A 100 g unit of a fishing net on which aquatic organisms adhered and propagated was cut off (about 20 cm × 20 cm, in this case, the wet weight of the fishing net alone was about 10 g), and a 70% highly exposed 0.2% aqueous solution 3 After immersion in a liter for 24 hours, the fishing net is taken out, washed with water, and the attached water is wiped off to measure the wet weight. Then, 2
After standing for 4 hours (air drying), the type and degree of the attached matter and the odor were observed with the eyes and nose of the observer. Comparative Example 2 The same treatment and observation as in Comparative Example 1 were performed, except that a 0.5% aqueous solution having a high exposure of 70 was used. Comparative Example 3 The same treatment and observation as in Comparative Example 1 were carried out, except that a 1.0% aqueous solution with a high bleaching of 70 was used. Comparative Example 4 The same treatment and observation as in Comparative Example 1 were carried out, except that a 70% aqueous 2.0% aqueous solution was used. Comparative Example 5 The same treatment and observation as in Comparative Example 1 were carried out except that a 60% highly exposed 0.5% aqueous solution was used.

[0012] As shown in Table 1, in Examples 1 and 2 which were washed with normal pressure after washing with hydrochloric acid (hereinafter simply referred to as washing with water), although about 30 g of seaweed remained, shellfish could be almost completely removed. By washing with high-pressure water, seaweed was completely removed. In this case, the odor of algae exists before washing with high-pressure water, but almost no odor remains on the fishing net after washing with high-pressure water. In Examples 3 to 5, which were treated with highly bleached powder, washed with water, and further treated with hydrochloric acid and then washed with water, only such a chemical treatment was used.
Shellfish and seaweed were almost completely removed, and little odor was left on the fishing net. In Example 6, which was treated with hydrochloric acid and then washed with water, and further treated with highly bleached powder and washed with water, shellfish and seaweed were completely removed, and almost no odor was left on the fishing net. On the other hand, Comparative Examples 1 to 1 which were washed with water after highly bleached powder alone treatment
In No. 5, most of the shellfish could not be removed, and some seaweed entangled in shellfish and fishing nets remained.

[Table 1]

[0013]

As described above, the invention according to claim 1 or 4 of the present invention can completely remove the calcareous shell attached to the fishing net and easily remove the algae attached to the fishing net easily. I do. Further, according to the invention of claim 2, 3 or 4, all the contaminating organisms attached to the fishing net can be easily removed at low cost without human labor, leaving no odor.

Claims (4)

[Claims] 1. A method for cleaning a fishing net with an aqueous solution of an inorganic acid. 2. The method for cleaning a fishing net according to claim 1, wherein the treatment is carried out with an advanced bleaching powder, a bleaching solution or an aqueous solution of hypochlorite, and then treated with an aqueous solution of an inorganic acid. 3. The method for cleaning a fishing net according to claim 1, wherein after treatment with an aqueous solution of an inorganic acid, treatment with an advanced bleaching powder, a bleaching solution or an aqueous solution of hypochlorite is performed. 4. The method according to claim 1, wherein the inorganic acid is hydrochloric acid.