JP2001212569A - Method for controlling propagation of bacteria, fungi and algae in water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple method for controlling the propagation of bacteria or the like in water capable of being easily performed even in a small-scaled apparatus such as a water cleaning storage tank or the like on the rooftop of a building or a method for controlling the propagation of harmful bacteria or the like in a nursery pond or the like without almost giving an antibiotic in the culture of fish to accelerate the growth of fish. SOLUTION: In a method for controlling the propagation of bacteria, fungi and algae in water by bringing a fiber or porous material having metal silver chemically plated on the surface thereof into contact with water to add eluted silver ions to water, as the fiber material, mole yarn, a fabric, a fiber web, a nonwoven fabric or a net is preferable. In a method for controlling the propagation of bacteria, fungi, algae and protozoa in water to accelerate the growth of fish by bringing supply water or circulating water to a nursery pond into contact with a packed bed containing fiber or porous material having metal silver chemically plated on the surface thereof to add eluted silver ions to water, as the packed bed, a mat wherein a net is filled with a web comprising fibers of which the surfaces are chemically plated, an aggregate of yarns comprising chemically plated fibers or a nonwoven fabric comprising chemically plated activated carbon fibers is preferable.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for suppressing the growth of bacteria, molds and algae in water by adding a small amount of silver ions to the water. By contacting the plated fiber with water, a small amount of silver ions eluted into the water suppresses the growth of bacteria, fungi, etc. in the water, thus preserving the water quality of water storage tanks, rainwater storage tanks, etc., or fish farms. Alternatively, the growth of fish is promoted by suppressing the growth of bacteria, fungi and the like supplied or circulated in the aquarium.

[0002]

2. Description of the Related Art Conventionally, a purified water storage tank on a building roof or
If the water in the rainwater storage tank is stored for a long period of time, bacteria, fungi, algae and the like will propagate in the tank, and the water quality tends to deteriorate. For this reason, a method of periodically injecting a small amount of sodium hypochlorite, such as liquid chlorine in some cases, has been adopted.However, this method is required for small-scale equipment due to side effects and considerable capital investment and operating costs. There were many problems including difficulty.

[0003] In addition, although fish cultivation is widely performed in facilities such as aquariums and fish ponds, there are many recently contaminated rivers and lakes and marshes. The harmful bacteria, fungi, or algae containing protozoa often breed to suppress the growth of fish and increase the mortality. Therefore, in these facilities, in order to suppress the growth of harmful bacteria and molds in the water, fish are managed so as to grow smoothly by administering a large amount of a drug containing an antibiotic as a main component.

It has been recognized that the use of these chemicals including antibiotics has the effect of suppressing the growth of harmful bacteria or fungi, algae, protozoa and the like, promoting the growth of fish, and reducing the mortality. However, on the other hand, there is a problem with resistant bacteria that do not improve the intended therapeutic effect even when antibiotics are administered recently in hospitals and the like. As one of the causes, since a large amount of antibiotics is used for fish culture, the effect of increasing the resistance of bacteria to antibiotics by entering the human body through the food chain is becoming a problem.

[0005]

In view of these problems, it is a simple method which can be easily carried out even with a small facility such as a purified water storage tank on a building roof, a rainwater storage tank, or the like. In order to promote growth and reduce mortality without administering antibiotics, we have developed a method to suppress the growth of harmful bacteria etc. in water such as aquaculture tanks or fishponds and promote the growth of fish. , What you want to offer.

[0006]

The present inventors have paid attention to the fact that the presence of a very small amount of silver ions in water has a large effect of suppressing the sterilization or propagation of algae including bacteria, molds and protozoa. , A relatively small building rooftop water purification tank,
We studied methods and devices that can be widely applied to aquariums such as rainwater storage tanks, or aquaculture tanks such as fish tanks or fish ponds, and ornamental fish tanks. There are two methods for generating silver ions in water: eluting silver ions into water from a metal silver electrode by electrolysis, and coating the surface of an object with a very large specific surface area, such as a fiber or porous material, with a thin film of metallic silver. There is a method in which silver ions are naturally eluted when they come into contact with water.

The method of generating silver ions by electrolysis requires not only an electrolytic facility and a power supply facility associated therewith, but also a facility for controlling the amount of silver ions generated. Therefore, in the case of outdoor fish farming facilities, a management building for installing these facilities is required, and an increase in capital investment is inevitable. On the other hand, a method in which a thin layer of metallic silver is formed on the surface of a substance having a large specific surface area and brought into contact with water does not require any auxiliary equipment such as a power supply facility, but a uniform thin layer of metallic silver is formed on the surface of the substance. The problem is how to form silver, whether or not a required amount of silver ions can be eluted, or whether or not a stable elution amount can be maintained.

It has been found that a chemical plating method is suitable for coating metallic silver on a surface of a material having a complicated shape such as a fiber in a uniform thin layer and in a state where it is difficult to peel off. In addition, as a result of various studies on the elution method of silver ions, a mat in which a web in which a silver thin film was chemically plated on a fiber surface was used as a filling layer containing metallic silver was filled in a net. Further, the mat is folded in two on a hanger, and a plurality of sets are immersed in a water tank to elute silver ions. By adjusting the residence time in the silver ion elution chamber, the silver ion concentration in the effluent becomes stable. It was found to be 6 to 8 ppb.

This water was supplied to a fish pond for a long period of time to investigate changes in water quality and the development of the sweetfish. As a result, compared to a fish pond supplied with water containing no silver ions, bacteria and fungi in the water were reduced. It was found that the reproduction was suppressed and the growth of sweetfish was remarkably promoted. Further, it was also confirmed that a decrease in the silver ion elution rate can be recovered by washing the mat plated with metallic silver chemically at regular intervals. Furthermore,
These methods are relatively small building rooftop water purification tanks,
It was found that it could be applied to rainwater storage tanks. In addition, the composition of the packed layer containing fibers or porous material whose surface is chemically plated with metallic silver and the structure of the silver ion elution chamber were examined, and a dissolution tank having a structure capable of maintaining a concentration suitable for use for this purpose was examined. Developed and arrived at the present invention.

That is, a method for inhibiting the growth of bacteria, fungi and algae in water, which comprises contacting water with a fiber or a porous material whose surface is chemically plated with metallic silver to contain silver ions eluted in the water. is there. Here, it is preferable that the fiber obtained by chemically plating metallic silver on the surface is in the form of a molding thread, a woven fabric, a fiber web, a nonwoven fabric, or a net.

[0011] In addition, water supplied or circulated to the fish farm,
Contacting a packed layer containing fibers or porous material whose surface is chemically plated with metallic silver, and containing silver ions eluted in the water, the control of fish in the water by inhibiting the growth of bacteria, molds, algae and protozoa It is a growth promotion method. Here, as a filling layer containing fibers or a porous material whose surface is chemically plated with metallic silver, a mat filled with a web made of fibers whose surface is chemically plated with metallic silver, or a fiber whose surface is chemically plated with metallic silver is used. More preferably, a non-woven fabric made of activated carbon fiber whose surface is chemically plated with metallic silver is used.

Further, the present invention includes a fish farm supply water or circulating water treatment tank. The treatment tank 1 for supplying or circulating water to the fish farm comprises a sedimentation chamber 2, a filtration chamber 3 and a silver ion eluting chamber 4, and the supply water or circulating water is injected into the sedimentation chamber 2 to settle suspended matters and filter. The chamber 3 is provided with a filtration layer 6 to remove suspended matter in water. Further, the silver ion elution chamber 4 is provided with a filling layer 5 containing fibers or porous material whose surface is chemically plated with metallic silver. The filling layer 5 is held in a state of being immersed in water to elute silver ions into water,
It has the function of imparting water with an effect of inhibiting the growth of bacteria, molds, algae and protozoa.

Here, the filling layer containing the fiber whose surface is chemically plated with metallic silver comprises at least one set of silver ion eluting units. The unit hangs a strip-shaped mat filled with a web made of fiber whose surface is chemically plated with metallic silver onto a net so that it hangs on both sides on a horizontal hanger, using a hanger and a mat shape holding bar at that time. It is preferable that the mat has a structure for holding the folded mats so that the insides do not contact each other.

Here, a fish farm is a water area for culturing fish that is isolated from natural rivers, lakes and marshes and the sea or separated by nets or the like, and is a facility capable of artificially controlling the environment. Algae may also contain protozoa that inhibit the growth of fish. Hereinafter, the present invention will be described in detail.

When water in a purified water storage tank or a rainwater storage tank on the roof of a building is stored for a long period of time, bacteria, fungi and algae propagate in the tank, and the water quality tends to deteriorate. Also, when tap water is purified through a small water purifier, a small amount of sodium hypochlorite, chlorine, etc., contained in the tap water at first is adsorbed on the activated carbon and removed, and bacteria, fungi, etc. propagate. It is difficult to store for a long time. In such a case, when a minute amount of silver ion is eluted into water by contacting water with a fiber whose surface has been chemically plated with metallic silver, even a very small amount that is harmless to hygiene of less than a few ppb is harmful to bacteria. And a remarkable effect of suppressing the propagation of fungi and the like.

The component of the fiber whose surface is chemically plated with metallic silver is not particularly limited, but polyethylene or polypropylene, polyamide, polyester, acrylic polymer,
Synthetic fibers made of polyvinyl alcohol or the like, or regenerated or semi-synthetic fibers such as rayon or cellulose acetate fibers, and natural fibers such as cotton, hemp, or silk can be used. Among these, fibers made of polyester, polyamide or polyvinyl alcohol are more preferred. In addition, the form of the fiber is a shape having a large contact area in water, that is, a form having a large specific surface area is particularly preferable, and a molding yarn or a woven fabric,
Preferred are fibrous webs, nonwovens and nets. As a method for eluting silver ions, a method of immersing these fibers having silver supported on the surface thereof in water to elute silver ions naturally into water is suitable.

As a method of forming a thin layer of metallic silver on the surface of a substance, there are known a method of applying and bonding silver fine powder, an electrolytic or electroless plating method, a vacuum evaporation method, a chemical plating method and the like. Have been. However, on the surface of a material having a large specific surface area and a complex surface shape such as a fiber or a porous surface suitable for the present invention, an extremely thin and uniform thickness, which is difficult to peel off even after long-term use. In order to form a layer, it is necessary to use a chemical plating method. If metallic silver is adhered to the surface of these substances by other methods, it will not only withstand long-term use due to the large amount of peeling and falling off, but also the depletion of silver by the incorporation of metallic silver into the water. This is in order to prevent the function from deteriorating. To form a thin layer of metallic silver by a chemical plating method, for example, a silver nitrate solution, which is a water-soluble silver compound, is infiltrated into the tissue of these substances, and then reduced to form a thin layer of metallic silver on the surface. For example, a method for causing the above to occur can be applied.

Further, in the present invention, in order to suppress the growth of algae containing bacteria, molds or protozoa (giardia) in a fish farm, water supplied to the fish farm or circulating water is treated to contain silver ions, Is injected into a fish farm. Fish farms can be used for fish cultivation as described above, and can be used to artificially control all or part of the environment in a water area separated or isolated from natural rivers, lakes, and oceans by nets, etc. Extensive facilities are included. For example, a fish culture tank, a fish pond, or a pool.
Water from rivers and lakes is often used for water supply to fish farms, but spring water and tap water are also used in some cases.

The type of fish to be cultivated is not particularly limited, but is mainly used for freshwater fish such as ayu and koi. It is also effective in preserving the water quality of the aquarium and in preventing contamination of the glass or transparent plastic plate due to mold and algae propagation.

In the present invention, it is necessary to bring water into contact with a filler layer containing fibers or porous material whose surface is chemically plated with metallic silver. As a carrier for coating metallic silver on the surface, a substance having a large specific surface area capable of stably holding a thin layer of metallic silver physically and chemically, for example, a structure including fibers such as fibers, webs, yarns, woven fabrics, knitted fabrics, and nonwoven fabrics A porous sheet or a three-dimensional structure such as a body or a permeable polyurethane foam, a three-dimensional mesh knit, activated carbon, ceramic beads, or a tube can be widely used. Web, yarn or activated carbon fiber, or a composite thereof is more preferable in view of the dissolution property of these middle silver ions.

When the surface of such a carrier having a large specific surface area is chemically plated with metallic silver and immersed in water, a very small amount of silver ions are naturally eluted into the water. The silver ion concentration eluted in water varies depending on the material of the carrier, the surface shape, the state of the thin layer of metallic silver, the water temperature and the contact time, etc.
It is in the range of about 30 ppb.

The present invention is used to treat feed water or circulating water to a fish farm and inject it into the fish farm. Water supplied to these fish farms may be river water, lake water, well water or spring water, and in some cases tap water.
Most commonly used is natural river water, well water or spring water.However, rivers and lakes have recently been contaminated in many places, and microorganisms harmful to fish and shellfish such as various bacteria, molds, and algae. Is also included. If left untouched, these microorganisms will grow in the water of the fish farm,
Bacterial infections or fungi, algae, protozoa, etc. parasitize the body of fish and inhibit the growth of ayu, carp, etc.

It has been known that the presence of trace amounts of silver ions in the water, on the order of ppb, has a bactericidal effect on various bacteria and molds. In addition to suppressing the propagation of fungi and fungi, it also has the effect of significantly promoting the growth of cultured fish such as ayu and koi. This growth promoting action is an example of ayu cultivation as described in the embodiment of the invention described later, and the average mortality during the cultivation period is 25 to 32% as compared with the case where the supply water does not contain silver ions.
The effect is so low that the weight increase rate of the sweetfish that can be shipped is improved by about 20 to 25%.

Further, as a result of a water quality inspection using a microscope, it was found that the number of protozoa present in the water of the fish farm was considerably reduced. This is also considered to be a factor that promotes the growth of fish, and the effect of silver ions on the promotion of fish growth is one of the most important requirements of the present invention.

In the process of sterilizing microorganisms such as bacteria, silver ions are considered to be adsorbed on the cell membrane of bacteria, and as a result, silver ions in water gradually decrease. Furthermore, silver ions are consumed for various other reasons. For this reason, in order to constantly suppress the growth of bacteria, molds, algae, protozoa, and the like in the fish farm, it is necessary to constantly replenish the reduced amount thereof.

In the present invention, there is no particular limitation on the packing layer containing fibers or porous material whose surface is chemically plated with metallic silver, which is used to elute silver ions into the water supplied or circulated to the fish farm. However, since it is a method of naturally dissolving in water, a structure in which a metal silver thin film is chemically plated on a material having a large specific surface area in contact with water as much as possible is preferable. Considering that it is easy to wash even if organic matter in water adheres to the plating surface, a fiber mat obtained by chemically plating metallic silver on the fiber surface is used as a web, and this is filled in a net. Is more preferable because the water circulation inside is high and the specific surface area is very large.

[0027] The silver ion eluting mat is formed by chemically plating metallic silver on the surface of each fiber and then putting the web into a bag-like net in a state of a web having a structure having a suitable water flow. The structure is such that it does not disperse and disperse in water. When using in the ion elution tank of the feed water of the fish farm, hold it in water using a hanger and a shape holding bar as described in the embodiment below, and make sure that the metal silver plating surface is in sufficient contact with water. At the same time, it is preferable to keep the water in a state of having an appropriate fluidity. In this form, if the silver-plated surface of the fiber surface is coated with an organic material,
Since it can be easily put into the washing machine while it is still in the net, it is easy to reproduce. Further, it may be hung on a hanger and held in water so as to have a wavy cross section, or a fiber obtained by chemically plating metallic silver may be used as a nonwoven fabric.

As the filling layer containing the fiber whose surface is chemically plated with metallic silver, a yarn whose surface is chemically plated with metallic silver or an aggregate thereof can also be used. here,
The yarn refers to a form in which the fibers are aligned in the length direction and loosely twisted to form a thread. In the present invention, it is preferable that the surface of each fiber is chemically plated with metallic silver and then spun into a thick yarn by spinning so that the enveloping state between the fibers is as coarse as possible. For example, the yarns may be arranged in parallel so that the overall shape is rectangular, and the vertical or horizontal center lines may be joined together and hung on a hanger or the like to be held in water. Even when the silver-plated surface of the fiber surface is coated with organic matter,
Washing is easy because it is in a yarn state.

As a filling layer containing fibers whose surfaces are chemically plated with metallic silver, activated carbon fibers can be chemically plated with metallic silver on the surface and then felted to be used as a nonwoven fabric. This has a function as a nonwoven fabric obtained by chemically plating metallic silver on the surface of the fiber and also has a function as activated carbon. The activated carbon fiber used as the base material here has a large surface area of usually several hundred to 2,000 m ² or more per gram and can be used in a wide range as long as it is a fibrous carbon material exhibiting high adsorptivity. Acrylic, phenolic or cellulose fibers are used as the raw material for the activated carbon fibers, but any of them may be used.

The activation method may be one obtained by using steam or carbon dioxide at a high temperature or by a method such as treatment with zinc chloride, phosphoric acid or concentrated sulfuric acid. Activated carbon is a unique substance that has extremely excellent adsorptivity as a nonpolar adsorbent.
It is known to exhibit high adsorptivity to almost all gaseous or liquid substances. The water of rivers and lakes usually contains fine suspended solids and organic substances, but also has a good water purification function of absorbing and removing these impurities.

In the present invention, when preparing water containing silver ions to be injected into a fish farm, either water to be newly supplied to the fish farm or circulating water of the fish farm may be used. But,
The circulating water of the fish farm contains much larger amounts of suspended solids and organic matter than the newly supplied water, and these impurities tend to adhere to the surface of the silver plating layer and reduce the elution amount of silver ions. Therefore, part of the circulating water is released, and the rest is returned to the fish farm as it is only by filtering trash and suspended matter, and only fresh water is brought into contact with the silver plating layer to elute silver ions and supply it to the fish farm. The system is preferred. Since the water is usually circulated at a certain speed inside the fish tank or fish pond, the water is rapidly diffused, so that there is no possibility that the concentration of silver ions becomes uneven.

For this reason, it is suitable to use a system in which a silver ion eluting tank is provided at a supply port of new makeup water at a fish farm, and new makeup water containing silver ions is supplied to the fish farm. The use of the method of the present invention has the effect of greatly reducing the amount of antibiotics conventionally used and promoting the growth of fish.
In addition, despite the fact that antibiotics are rather expensive, they have been used at relatively high concentrations in fish farms in the past, occupying a considerable weight in aquaculture costs as well as in the problem of resistant bacteria. Therefore,
If a significant reduction is possible, the cost reduction effect will be great. On the other hand, the consumption amount of silver has a low running cost because the elution amount is a concentration on the order of ppb, and there is almost no hygienic or environmental obstacle. The concentration of silver ion in water is measured by the atomic absorption method. However, when the concentration cannot be measured directly because the concentration is extremely low, the concentration can be measured by concentrating the sample.

The water supplied to the fish farm is often natural river water, well water or spring water, but often contains considerable garbage, minute suspended matters and other organic substances. When a web carrying metal silver, a fiber structure such as yarn or a porous material such as activated carbon and water are in contact for a long time,
While silver ions elute into water, organic substances and the like in the water gradually adhere to the surface of these carriers, and a thin layer of metallic silver is coated to gradually reduce the silver ion elution rate.

When a thin layer of metallic silver is coated on the surface of a fibrous structure or a porous carrier carrying metallic silver by the application of organic substances in water and the like, the attached organic substances are washed by washing or the like. If a thin layer of metallic silver is exposed, the elution rate of silver ions is restored. Therefore, it is practically important that the fibrous structure or porous material supporting metallic silver not only has a high silver ion elution rate but also has a structure in which the surface of these carriers is easily washed by washing or the like. It becomes a problem. By always paying attention to these points, a substantially constant silver ion elution amount can be maintained.

[0035]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to examples.

(Example 1, Comparative Example 1) Except for the rainwater accumulated at the beginning of falling, rainwater was collected in 18 l each into two 20 l translucent containers made of polypropylene. One of the containers was immersed in a silver molding yarn 30 cm chemically plated with silver and left outdoors for one month (Example 1). The other container was similarly left outdoors outdoors for one month for comparison (Comparative Example 1).

As a result of being left outdoors for one month,
Almost no change was observed in the water in the container in which 30 cm was immersed. However, the water in the container was left as it was, and a blue spider, a kind of green algae, was generated and the water turned green. Table 1 shows the results of analysis of the water based on the provisions of the Water Supply Law.

[0038]

[Table 1]

According to the results of observation of the state of water in both containers after standing and the above-mentioned analysis values, the container immersed in the silver-moulded yarn chemically plated with silver is generally more in comparison with the water in the container not immersed in the silver-moulded yarn. It is recognized that the generation of chromaticity, turbidity, pH value and evaporation residue of bacteria, organic matter, etc. is extremely low.

Example 2 and Comparative Example 2 Ayu was cultured in a fish pond with a water volume of 40 m ³ using spring water in the mountains. The spring water contained fine suspended matter and organic matter. In the conventional aquaculture method, fry of ayu is arriving at an average of about 5g / animal, and the cultivation period fluctuates depending on the season and water temperature.
g / One adult fish is shipped. Observation of the water quality during culturing with a microscope reveals that bacteria, fungi and other protozoa are breeding.

As the feed for aquaculture, a commercially available feed for sweetfish is used.
Contains propolis from a Brazilian honeycomb. Because of the high density of ayu in the culture pond, it may be damaged by the contact between the sweetfish and the sweetfish, etc., and the aquaculture is technically very difficult, and the conventional method requires administration of a considerably large amount of antibiotics.

In the following, for comparison tests of the conventional aquaculture method and the method of the present invention, fry hatched from eggs of the same parent fish were divided into two groups, one of which used water treated in the silver ion elution tank of the present invention. The animals were cultured without administration of antibiotics (Example 2). On the other hand, they were cultured under the same conditions as those described above, except that no water not treated in the silver ion elution tank was used (Comparative Example 2). In the aquaculture method of the present invention, in order to contain silver ions immediately before supplying spring water to a fishpond, a feedwater treatment tank described below, which is loaded with a web coated with 500 g of metallic silver on the fiber surface in a mesh bag. (Example 7). The spring water was treated by this apparatus and supplied to a fish pond at a silver ion concentration of 6 to 8 ppb.

A comparison of the results of a few months of aquaculture tests under these conditions reveals that the method of the present invention significantly improves the mortality of Ayu and the growth rate of Ayu, and the mortality of Ayu is 25% lower than that of the conventional method. Ayu decreased by ~ 32%, and Ayu shipments increased by 20-25%. In addition, observation of the quality of both waters under a microscope during the culturing period revealed that the breeding state of bacteria, molds and other protozoa was significantly reduced in the method of the present invention as compared with the conventional method.

As a result, it was found that when the method of the present invention was applied to a fish pond, it had a remarkable effect of suppressing the growth of bacteria, molds or protozoa, and an effect of promoting the growth of fish.

(Example 3) In addition, as a result of performing a carp culture test on other sweet fishes as well, the ratio of the decrease in mortality and the increase in the amount of shipment was 60-70% as compared with the sweetfish, but the bacteria and fungi In addition, it was confirmed that there was a sufficient inhibitory effect on the reproduction of the protozoa and an effect of promoting the growth of carp.

(Examples 4 to 6, Comparative Example 3) A part of the water stored in a dam in a mountainous area was introduced into a fishpond to cultivate amago. Amago fry is usually placed in a culture pond in the spring and bred for 6-7 months and shipped as an adult in the fall. The water for aquaculture is taken into the fish pond by flowing the reservoir water of the dam about 100m side ditch, and the water temperature is about 17-22 ℃ suitable for aquaculture. This aquaculture water is clean except for a small amount of garbage, but it is a problem because it often contains bacteria that can inhibit the growth and death of amago.

The aquaculture water is filtered through a net before entering the fishpond to remove debris in the water, and then passed through a mesh bag containing silver mall yarn to make the supply water contain silver ions. It is supplied to the pond. The fish ponds were modified octagons and the amago diet used was a commercial feed for amago.

Hereinafter, for comparison with the method of the present invention, fry hatched from the same parent fish egg are divided into two groups. One of them is that administration of an antibiotic using water in which silver ions are eluted by the method of the present invention. Farmed without doing. In this apparatus, the metallic silver carrying amount 70 g (Example 4), 140 g (Example 5) and 210
g (Example 6) silver-coated moldings are sequentially attached,
After treating the feed water, it was supplied to a fish pond. Table 2 shows the weight of the metallic silver loaded in the feed water treatment apparatus, the test period, and the average number of ayu killed per day during the test.

For comparison, amago was cultivated under the same conditions except for feeding and other aquaculture water except that the aquaculture water not passing through the above-mentioned feed water treatment apparatus was supplied (Comparative Example 2). Table 2 also shows the test period and the average mortality of ayu per day during the test.

[0050]

[Table 2]

From these results, it can be seen that when a trace amount of silver ions is contained in the water supplied to the fishpond, the mortality of amago during the cultivation period is significantly reduced.

When the silver ion concentration of the water supplied to the fishpond was set at 6 to 8 ppb, which is within a range that is completely harmless in terms of sanitation, the results of the culture test for several months under these conditions were compared. It can be seen that the mortality of Ayu and the growth rate of Ayu are significantly improved. Ayu mortality was reduced by 25-32% compared with the conventional method, and shipment of ayu was improved by 20-25%. In addition, observation of the quality of both waters by a microscope during the culturing period revealed that the breeding state of bacteria, fungi and other protozoa was significantly reduced in the method of the present invention as compared with the conventional method.

As a result, it was confirmed that when the method of the present invention was applied to a fish pond, it had a remarkable effect of suppressing the growth of bacteria, molds or protozoa and an effect of promoting the growth of fish.

(Embodiment 7) Hereinafter, the structure and function of a tank for supplying or circulating water to a fish farm included in the present invention will be specifically described with reference to the drawings. FIG. 1 is a plan view of the processing tank of the present invention, FIG. 2 is a front view thereof, and FIG.
2 is a sectional view taken along the line AA ', and FIG. 4 is a sectional view taken along the line BB' in FIG.

Treatment tank 1 for supply water or circulating water to fish farm
Consists of a precipitation chamber 2, a filtration chamber 3, and a silver ion elution chamber 4. Feed water or circulating water is injected into the precipitation chamber 2 from the inlet 18 of the treatment tank 1 and sediments suspended matters while staying in the precipitation chamber 2 at a reduced flow rate. The settled suspended matter is periodically withdrawn from the lower outlet of the settling chamber and discarded. The supernatant liquid from which the suspended matter has settled next enters the filtration chamber 3 and is filtered by a filtration layer 6 provided therein to remove fine suspended matter in water. The filter layer 6 is periodically cleaned to restore its function and used repeatedly. The filtered water enters the silver ion elution chamber 4 and, while staying inside the silver ion elution chamber 4, comes into contact with a filler layer 5 containing fibers or porous material whose surface is chemically plated with metallic silver immersed in the chamber. Is eluted in water. Water containing silver ions has the effect of inhibiting the growth of microorganisms such as bacteria and molds or algae and protozoa in fish farms,
The effect of promoting the growth of fish is recognized.

The structure of the filling layer 5 including the fiber provided on the surface of the silver ion elution chamber 4 and chemically plated with metallic silver is not particularly limited, and has a wide range of structure as long as a constant amount of silver ion is always eluted. It is possible. Among these preferred embodiments, a structure including at least one set, usually a plurality of sets of silver ion eluting units 7 will be described. FIG. 5 is an exploded view of a mat 10 in which a net 9 is filled with a web 8 whose surface is chemically plated with metallic silver, and FIG. 6 is a perspective view of the mat 10 in a state where left and right edges 14, 14 'are folded inward. FIG. 7 shows a side view of the silver ion eluting unit 7.

The silver ion eluting unit 7 has an elongated strip-shaped mat 10 in which a web 8 made of nylon fiber chemically plated with metallic silver on the surface is filled in a bag-shaped net 9, a mat hanger 11, and a shape holding bar 12. , 12 '.

Hooks are attached at regular intervals to the left and right edges 14, 14 'of the mat 10 and the central portions 13, 13' of the mat 10, and the left and right edges 14, 14 'of the mat are arranged as shown in FIG. It is folded back and attached to the central parts 13 and 13 'with hooks. At this time, the horizontal cross section in FIG. 6 has a flat figure-eight shape. Further, the mat is hung on at least one hanger 11 horizontally mounted inside the silver ion elution chamber 4 so that the mat is folded back at the center, and the cross section of the mat hanging on both sides of the hanger is shown in FIG. Each of them has a loop shape, and mat shape holding bars 12, 12 'are inserted horizontally into the lower ends thereof.

Here, the hanger 11 has a structure in which the folded mat does not contact each other, and the shape holding bars 12, 12 'are held in water so that the inside of the mat 10 having a loop-shaped cross section does not contact each other. It has become. Each of these gaps serves as a passage for water that is stagnating. The silver ion elution chamber is provided with at least one set of silver ion elution units 7 having such a structure, usually several sets in parallel,
The silver ions are eluted into the water that is held in a state of being immersed in water and is in contact with the mat 10.

After the suspended matter contained in the water in the treatment tank 1 is removed in the precipitation chamber 2 and the filtration chamber 3, the water enters the silver ion elution chamber 4, where silver ions are eluted while staying. 6
The residence time is set in advance so that the concentration becomes ８8 ppb. The water treated in the treatment tank 1 is taken out from the outlet 19 and supplied to the fishpond as it is.

If the mat 10 is used for a certain period of time, impurities in water such as organic substances adhere to the mat 10 to cover the surface of the silver plating layer, and the silver ion elution rate is reduced. In such a case, it can be replaced with a new mat and the use can be continued. In addition, both ends 14, 14 'of the removed mat and the center of the mat
The hook connecting 13 and 13 'is removed, and the mat can be developed in a strip shape and washed while remaining in the net 9, thereby easily recovering the silver ion elution rate. Can be used repeatedly.

The ayu culture test described above was conducted using the processing tank 1 in which four sets of the silver ion eluting units 7 were installed. Since this treatment tank is lightweight enough to be transported by one person, it is easy to handle such as installation, removal and movement, and compared to the electrolytic silver ion elution tank that requires complicated electric equipment as an accessory equipment. Equipment costs and operating costs can be significantly reduced.

As another embodiment of the silver ion eluting unit, FIG. 8 shows a unit 15 in which a filling layer containing fibers chemically plated with metallic silver on the surface is a yarn aggregate composed of fibers chemically plated with metallic silver on the surface. Show. As shown in the figure, one or more thick coarse yarns 16 made by spinning an ester fiber obtained by chemically plating a thin layer of metallic silver on the surface of the fiber are arranged, and the central part thereof is fixed by a band 17. band
The portion 17 is hung on the hanger 11 of the silver ion elution chamber, the yarn is hung on both sides, and immersed in water for use. If impurities in water such as organic matter adhere to the yarn after a certain period of use and the silver plating layer is coated, and the silver ion elution speed decreases, the silver ion elution speed can be easily recovered by removing and washing. It can be used repeatedly as described above.

[0064]

The present invention relates to a method for suppressing the growth of bacteria, molds and algae in water by adding a very small amount of silver ions to the water. Effective for conservation. Conventionally, large amounts of antibiotics have been administered to fish and fish breeding farms in order to prevent the propagation of bacteria, fungi, and protozoa.However, when the method of the present invention and the treatment tank are applied to a fish farm, no antibiotics are administered. Even when compared with the conventional method, the mortality due to bacterial infection or protozoan parasites of Ayu was significantly reduced, and the effect of promoting the growth of fish was observed. Further, when the silver metal elution rate of the metal silver carrier of the present invention decreases due to the attachment of organic substances to the surface, the reduction of the elution rate can be easily recovered by washing. Antibiotics administered by conventional methods accumulate in the body of fish and cause the development of resistant bacteria by the food chain. In addition, the method of the present invention has a significant effect of contributing to the improvement of the environment such as the promotion of growth of fish in fish farms, the conservation of water quality in ornamental fish tanks, the prevention of molds on glass and transparent plastic plates, and the prevention of contamination due to the propagation of algae.

[Brief description of the drawings]

FIG. 1 shows a plan view of one embodiment of a treatment tank for supplying or circulating water to a fish farm according to the present invention.

FIG. 2 shows a front view of the processing tank shown in FIG.

FIG. 3 is a sectional view taken along the line AA 'in FIG.

FIG. 4 is a sectional view taken along line BB ′ of FIG. 2;

FIG. 5 is a development view of a mat including a fiber chemically plated on its surface with metallic silver included in one embodiment of a silver ion eluting unit.

FIG. 6 is a perspective view of the mat shown in FIG. 5 in a state where left and right edges 14, 14 ′ are folded inward.

FIG. 7 shows a side view of one embodiment of a silver ion elution unit.

FIG. 8 is a development view of a yarn polymer containing a fiber whose surface is chemically plated with metallic silver contained in one embodiment of the silver ion eluting unit.

[Explanation of symbols]

1 Treatment tank for feed water or circulating water to fish farm 2 Sedimentation chamber 3 Filtration chamber 4 Silver ion elution chamber 5 Packing layer containing fiber or porous material with metal silver on the surface 6 Filtration layer 7 Silver ion elution unit 8 Web with chemical silver plated metal surface 9 Net 10 Mat filled with metal silver chemically plated web surface 11 Mat hanger 12, 12 'mat shape retention bar 13, central part of 13' mat 14, 14 'mat left and right edge 15 Aggregate made of fiber chemically plated with metallic silver on the surface 16 Yarn 17 Band 18 Treatment tank entrance 19 Treatment tank exit

Claims (6)

[Claims] 1. A method for suppressing the growth of bacteria, fungi and algae in water, comprising bringing water or fibers and porous material whose surface is chemically plated with metallic silver into contact with water to contain silver ions eluted in the water. 2. A fiber chemically plated with metallic silver on its surface,
The method for suppressing the growth of bacteria, fungi and algae in water according to claim 1, wherein the method is at least one form selected from the group consisting of a mottled yarn and a woven fabric, a fiber web, a nonwoven fabric and a net. 3. A method in which water or circulating water supplied to a fish farm or an appreciation fish tank is brought into contact with a filler layer containing fibers or a porous material chemically plated with metallic silver on its surface to contain silver ions eluted in the water. A method for promoting fish growth or conserving water quality by suppressing the growth of bacteria, fungi and algae in water. 4. A filling layer containing fibers whose surfaces are chemically plated with metallic silver, wherein the filling layer is made of a mat or a collection of yarns or an activated carbon fiber which is filled with a web made of fibers whose surfaces are chemically plated with metallic silver. The method according to claim 3, wherein the method is a nonwoven fabric or a complex thereof, wherein the growth of fish is suppressed or the quality of water is preserved by inhibiting the growth of bacteria, fungi and algae in water. 5. A treatment tank 1 for supplying or circulating water to a fish farm or an appreciation fish tank comprises a sedimentation chamber 2, a filtration chamber 3 and a silver ion elution chamber 4, and the supply water or circulating water is injected into the sedimentation chamber 2. Then, the suspended matter is settled, and a filtration layer 6 is provided in the filtration chamber 3 to remove micro suspended matter in water, and the silver ion elution chamber 4 contains fibers or porous material whose surface is chemically plated with metallic silver. A filling layer 5 is provided, and the filling layer 5 is held in a state of being immersed in water, elutes silver ions into the water, and has a function of giving the water an inhibitory effect on the propagation of bacteria, molds and algae, or water supplied to a fish farm. Circulating water treatment tank. 6. A packing layer provided in a silver ion elution chamber and containing fibers chemically plated with metallic silver on the surface thereof comprises at least one set of silver ion elution units. An elongated strip-shaped mat 10, a mat hanger 11, and mat shape retaining bars 12, 12 'are filled in a net 9 with a web 8 made of silver chemically plated fiber on the surface. The mat is folded back and attached to the center 13 and 13 'of the mat. The cross section in the longitudinal direction of the mat has a flat figure-eight shape, and the mat is centered on the hanger 11 mounted horizontally inside the silver ion elution chamber 4. The cross section of the mat that is hung so that it is folded back and hangs on both sides of the hanger becomes a loop-shaped section, and the inside of the lower end of the mat is horizontally held by the mat.
12 and 12 'are inserted. At this time, the hanger 11 does not come into contact with the folded mat, and the shape retention bars 12, 12' are also held in water so that the inside of the loop-shaped mat does not come into contact with each other. The fish farm feed water or circulating water treatment tank according to claim 5, which has a sloping structure.