JPH09313055A - Sterilizing device for circulation type nutritive solution culture device and sterilization of nutritive solution with the same, and circulation type nutritive solution culture device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sterilization device for a circulation type nutritive solution culture device, capable of removing waste matters excreted from the roots of plants, suppressing the propagation of pathogenic microbes for root rots, etc., in the culture solution, and unnecessitating the exchange of the culture solution or remarkably reducing the number of the exchange operations, excellent in environmental pollution prevention and realizing the culture free from an agrochemical by using activated carbon. SOLUTION: Activated carbon such as silver-adhered activated carbon or activated carbon to whose surfaces titanium dioxide is adhered is used. This sterilization device for a circulation type nutritive solution culture device has an activated carbon-charged tank 5 and preferably further an ultraviolet light- irradiating device and a titanium dioxide tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circulating-type hydroponic cultivation apparatus, a circulating-type hydroponic cultivation apparatus, and a nutrient solution sterilizing method. The circulation type hydroponics device of the present invention, in the circulation type hydroponics such as hydroponic culture and solid medium culture, suppresses the propagation of pathogenic bacteria that cause diseases such as root rot in the nutrient solution, and Also, waste products (water-soluble organic matter) discharged from the roots can be removed, and such a nutrient solution cultivation device is suitable for use as a nutrient solution cultivation device that does not require replacement of nutrient solution. It is something.

[0002]

2. Description of the Related Art Hydroponics for cultivating crops using an aqueous solution containing nutrients required for plants (hereinafter referred to as "culture liquid") in place of soil is largely used for hydroponic cultivation and solid medium cultivation. Hydroponics is divided into submerged hydroponics and culture solution thin-film hydroponics (NF
T) and solid medium cultivation are represented by rock wool cultivation, gravel cultivation, sand cultivation and the like.

In the fiscal year 1993, the hydroponics area of Japan was 690ha, and the submerged hydroponics was 278ha (40%).
And most, followed by rock wool cultivation 256ha (37
%) And NFT 102ha (15%), and these three methods account for 92% of the total. Submerged hydroponics and culture solution thin-film hydroponics (NFT) are circulation type that reuses culture medium, and rock wool cultivation is circulation type and non-circulation (overflow).
There is a ceremony, but due to environmental problems such as pollution of groundwater and rivers, it is shifting to a circulation method.

At present, the main liquid immersion type hydroponic systems that are commercially available are M type hydroponic, Kyowa type hyponica, Shinwa type equal amount exchange hydroponic, Shinwa type NS hydroponic, Sekisui Suikomate, Kaneko EK.
It is a type hydroponic, JT Rakuno Jiro, etc. In all of these, the cultivating bed is composed of a lightweight styrene molded product, and the culture liquid is collected and circulated in the liquid storage tank, and the cultivating bed also serves as the liquid storage tank, and the culture liquid is stored in the bed. There is a reflux type. Each hydroponic method has its own unique oxygen enrichment method, and a supply / drainage device and culture solution control method. The submerged hydroponic method is characterized in that the root temperature is not affected by the temperature in the greenhouse because a large amount of culture solution exists in the root area. The culture medium is usually controlled by temperature, pH and EC value.

[0005] Hydroponics has been researched and developed as a cultivation method that can avoid soil-borne diseases, so its most important feature is that continuous cropping failures can be avoided and the amount of crops is large. On the other hand, however, unlike soil, there are no antagonistic bacteria against pathogenic bacteria, and the damage caused when the pathogenic bacteria jump into the cultivation bed or the culture solution circulation system is extremely large. It does not have a buffering effect like soil, it is easy to spread pathogenic bacteria, has many opportunities to contact roots, and when bacteria are mixed in the culture solution, it is more easily spread than soil cultivation.

[0006] Generally, pathogenic bacteria in the culture medium propagate in the liquid in the form of spores, hyphae or zoospores, invade from roots, and cause root rot. Especially, Pythium and Rhizoctonia
Almost all hydroponic crops are affected by wilt disease and wilt disease caused by Fusarium. As a countermeasure against pathogenic bacteria, pesticides are usually used, and residual pesticides in cultivated products are more likely to be concentrated in hydroponic culture than in soil cultivated products, and have little effect on the human body. I could not say it, and I was anxious. Further, the culture solution is frequently replaced, but it cannot be said to be a preferable coping method in view of environmental problems such as pollution of groundwater and rivers, cost and labor. In addition, consumers strongly demand reduction of pesticides and elimination of pesticides, and a sterilization method that does not use pesticides has been demanded. As a sterilization method that does not use pesticides in hydroponics,
Although sterilization methods using ultraviolet rays, ozone, heating, etc. are known, it is difficult to obtain sufficient effects with only ultraviolet rays, and equipment such as heating devices and ozone generators are difficult to maintain and expensive. There was a problem.

In addition, these methods have little effect on the accumulation of waste products (water-soluble organic matter) discharged from the root, which is inevitable in the case of the circulation type in hydroponic culture, and the culture solution is regularly used. Need to be replaced.

[0008]

SUMMARY OF THE INVENTION The above-mentioned conventional circulation-type hydroponic cultivation device has a problem that the culture solution needs to be replaced, and the sterilizing device is expensive and the effect is insufficient. It is difficult to meet the demand for pesticide-free products, and the bactericidal effect is not sufficient in all cases. Therefore, considering the effects on the human body and environmental issues,
It is inexpensive, can suppress the propagation of pathogenic bacteria, can remove waste products (water-soluble organic matter) discharged from roots, and does not require replacement of culture solution. There is a demand for a sterilizing device for a circulating-type hydroponic device that can be easily attached to the hydroponic device.

[0009]

Therefore, as a result of intensive studies to solve the above problems, the present inventor has found that activated carbon, particularly a specific substance, in a hydroponics method such as hydroponic culture or solid medium culture. The inventors have found that such a problem can be solved by using a sterilizer using activated carbon to which is attached and have reached the present invention. That is, the object of the present invention is to remove waste products (water-soluble organic matter) discharged from the roots, and further suppress the propagation of pathogenic bacteria that cause diseases such as root rot in the culture solution, resulting in culture. It is an object of the present invention to provide a hydroponic cultivation device capable of remarkably reducing the number of times of exchanging the liquid, or in some cases not requiring the replacement.

The object of the present invention is achieved by a sterilizer for a circulating-type hydroponic device using activated carbon. , More preferably, the activated carbon is a sterilizer for a circulation type hydroponics device which is a silver impregnated activated carbon, and a sterilizer for a circulation type hydroponic device using an activated carbon having an ultraviolet irradiation device and a titanium dioxide tank as a more preferable embodiment, Also, the activated carbon is titanium dioxide surface-attached activated carbon, and can be easily achieved by a sterilizing apparatus for a circulation type hydroponic device having an ultraviolet irradiation device and a circulation type hydroponic device incorporating these sterilization devices.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The hydroponic cultivation apparatus of the present invention is a conventional hydroponic cultivation apparatus in which a sterilizing apparatus using activated carbon is incorporated, and conventional ones can be used as they are except the sterilizing apparatus using the activated carbon. Of course, a sterilizer using activated charcoal, which characterizes the present invention, may be added to an existing hydroponics device.

The form of using activated carbon in the apparatus of the present invention is not particularly limited as long as it is a form in which the nutrient solution can be sterilized by the activated carbon, for example, a filling tank is filled with the activated carbon and the nutrient solution is passed through. Absent. The activated carbon used in the present invention is preferably granular or fibrous activated carbon, coconut shell,
Wood, sawdust, charcoal, walnut shells and other plant systems
Anthracite, lignite, lignite, grass peat, peat, coke, coal tar, mineral pitch such as coal pitch, petroleum pitch, rayon,
Fiber-based activated carbon such as acrylic, phenol, or coal-based pitch is preferably used. Since the adsorptive capacity of activated carbon largely depends on the specific surface area, a small amount of activated carbon has a large specific surface area and a large amount of activated carbon has a large specific surface area. Due to the size limitation of the activated carbon filling tank, it is not preferable to use a large amount of one having a low specific surface area. Specific surface area is 100m ² /
The amount of activated carbon used may be determined in accordance with the amount of water used. For example, if the activated carbon is replaced once a year, 1000m ² / g for 100t of water
If a small amount of activated carbon is used, a minimum of 10 kg or more is suitable. Preferably 1 for 100t of water
It is 0 to 500 kg, more preferably 50 to 300 kg. When the amount used is in this range, it is most effective against pathogenic bacteria in the nutrient solution. The activated carbon filling tank may be a fixed bed or a fluidized bed, and may be an upward flow or a downward flow.

One of the preferred activated carbons used in the present invention is silver-impregnated activated carbon to which silver or a silver compound is attached. The silver-impregnated activated carbon may be produced by any method as long as silver or a silver compound is attached to the surface of the activated carbon. Regarding the amount of silver impregnated, 0.001 wt% to 3w
About t% is preferable, and the concentration may be adjusted to 20 ppb or more when expressed by the concentration of silver ions eluted into the nutrient solution.

In the case of using ordinary activated carbon, particularly when activated carbon to which silver or the like is not attached is used, a titanium dioxide tank filled with titanium dioxide photocatalyst may be provided since the bactericidal effect is low with activated carbon alone. As an example of a concrete titanium dioxide tank,
Examples include glass tubes or glass fibers coated with TiO ₂ by the sol-gel method. By irradiating this with ultraviolet rays, titanium dioxide, which is a photocatalyst, is excited by ultraviolet rays to generate holes, and OH that occurs on the surface thereof is generated. Sterilization is possible due to the oxidizing action of radicals. In this case, the activated carbon filling tank may be before or after the titanium dioxide tank, but it is more preferably installed before the titanium dioxide tank in order to prevent reduction of the ultraviolet irradiation effect due to the dirt of the titanium dioxide tank.

As the crystal form of titanium dioxide, the anatase type and the rutile type are preferable, and the anatase type is more preferable in view of the band gap. The coating film on the glass tube or glass fiber is preferably a porous film having a small primary particle size, and the primary particle size is preferably 1 μm or less, more preferably 100 nm or less. As for the coating method, the dip coating method is suitable because a porous film is formed by multilayer coating.

The light source used is not particularly limited as long as it contains a wavelength of 380 nm or less. The ultraviolet illuminance is preferably 10 μw / cm ² or more. If activated carbon having titanium dioxide on the surface is used, an ultraviolet irradiation device is required, but a titanium dioxide tank is not required, and the device becomes more compact. Further, since waste products that are adsorbed on the surface of activated carbon and concentrated are decomposed by the photocatalytic effect of titanium dioxide, there is an advantage that they can be used continuously for a longer period than other activated carbons.

By irradiating a tank filled with activated carbon particles adhering to titanium dioxide surface with ultraviolet rays, titanium dioxide, which is a photocatalyst, is excited by ultraviolet light to generate holes, and oxidization action of OH radicals generated on the surface thereof causes sterilization and waste. This is an epoch-making hydroponic cultivation device that decomposes and removes substances (water-soluble organic substances), and can further efficiently adsorb and remove waste substances (water-soluble organic substances) discharged from roots by activated carbon.

The titanium dioxide surface-attached activated carbon used in the present invention is an activated carbon characterized in that titanium dioxide is present on the surface and has a lightness L value of 50 or less, which was previously filed by the present inventors. Alternatively, in a method of pulverizing, granulating, crushing, carbonizing, and activating coal to produce a coal-based activated carbon, titanium dioxide is added to the coal before granulation. In the method of producing granulated activated carbon, which is characterized by coal-based activated carbon (Japanese Patent Application No. 7-187954) or raw material carbon, finely pulverized, kneaded with a binder, granulated, hardened and carbonized, and activated. Activated carbon such as granulated activated carbon (Japanese Patent Application No. 7-221965) characterized by adding titanium dioxide to the raw coal before granulation can be preferably used. For the amount of titanium dioxide on the activated carbon surface,
Depending on the size of each particle of activated carbon and titanium dioxide, the distribution of titanium dioxide (whether only the surface or uniformly mixed at the time of granulation), etc., it will be quite different if expressed in wt%, so titanium dioxide covers the surface. The lightness of the surface indicates a state in which the adsorption action of the activated carbon itself is not hindered and sufficient titanium dioxide for obtaining the effect is present on the surface. As a method of measuring such brightness, a round glass cell is filled with a spectroscopic color difference meter under the optical condition of 0 ° illumination and −45 ° light reception.

The shape of the titanium dioxide surface-adhered activated carbon particle filling tank is a cylinder or a cylinder in order to efficiently irradiate ultraviolet rays.
A flat plate is preferable, and in the former case, a double tube is used and a light source is installed in the inner tube, and in the latter case, a light source is preferably installed outside. The wavelength and illuminance of the light source used are the same as in the case of using the titanium dioxide tank described above.

An example of the nutrient solution sterilizing method of the present invention is shown in FIGS. FIG. 1 is a schematic diagram in which a fixed bed type activated carbon filling tank having a sterilizing function is installed in a general circulation type hydroponic cultivation apparatus. In FIG. 1, 1 is a cultivation bed, 2 is a liquid supply pump, 3 is a culture liquid tank, 4 is a fertilizer device, 5 is an activated carbon filling tank having a sterilizing function, 6 is a liquid supply pipe, and 7 is a waste liquid pipe.

The activated carbon filling tank may be installed adjacent to the culture solution tank by pumping it from the culture solution tank and returning it to the culture solution tank through the activated carbon filling tank having a sterilizing function. Either is preferably installed in the middle of the liquid pipe. FIG. 2 shows a schematic diagram when the activated carbon filling tank is a fluidized bed type and is adjacent to the culture solution tank. In FIG. 2, 8 is a pump, 9 is an activated carbon filling tank (fluidized bed), 10 is a titanium dioxide coated glass tube, and 11 is an ultraviolet lamp.

In FIG. 2, the activated carbon packed bed is a fluidized bed type, but it may be a fixed bed and is not particularly limited. When titanium dioxide surface-adhered activated carbon is used as the activated carbon, an ultraviolet lamp may be installed as shown in FIGS. In FIG. 2, the ultraviolet lamp is externally installed, but the glass tube may be doubled and the ultraviolet lamp may be installed in the central portion. The glass material is
A quartz tube having a high ultraviolet transmittance is more preferable, but a normal glass tube such as Pyrex may be used.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.
I do. Example 1 A bactericidal test was conducted on pathogenic bacteria that cause problems in hydroponics
Was. Mitsubishi Chemical silver impregnated activated carbon (silver content 1.9%, particle size
0.35-0.71 mm, specific surface area 1000 m ^Two/ g)
It was subjected to high-pressure steam sterilization treatment at 120 ° C. for 20 minutes. This sterilization process
Silver impregnated activated carbon (0.05 g) and soft rot fungus (Erwinia carot
ovora ssp.carotvora) concentration is 10⁶-10⁷5 of CFU / ml
25 ml of the aqueous solution is placed in a glass container with an inner diameter of 36 mm and
C. The number of bacteria is calculated by sampling 0.1 ml
Then, dilute it 100 times and perform it on an agar medium by the dilution plate method.
Was. Initial concentration is 1 x 10⁷CFU / ml, bacteria after 2 hours
Number is 1 × 10^ThreeIt was below CFU / ml. The silver concentration in the liquid is I
When measured by CP emission spectroscopy, 0.54ppm
Met. In this way, for hydroponics with silver-impregnated activated carbon
In order to have a great effect on sterilization of pathogenic bacteria which is a problem in
You can see that you can do it. Example 2 Instead of soft rot fungus, Fusarium oxyspor
um f. lycopersici small conidia)
An experiment was conducted in the same manner as in Example 1. Initial concentration is 8 × 10
⁶CFU / ml, the number of bacteria after 2 hours is 7 × 10^FiveIn CFU / ml
Was. In this way, the silver-impregnated activated carbon makes it possible to smell
Can be greatly effective in sterilizing pathogenic bacteria that cause problems
I know that I can do it. Comparative Example 1 Instead of silver-impregnated activated carbon, activated carbon DIAHOPE manufactured by Mitsubishi Chemical
006S (particle size 0.35-0.71mm, 1000m^Two/
An experiment was conducted in the same manner as in Example 1 except that g) was used.
Was. The number of bacteria after 2 hours is 3 x 10^FiveCFU / ml. Comparative Example 2 Instead of silver impregnated activated carbon, activated carbon diahope manufactured by Mitsubishi Chemical
006S (particle size 0.35-0.71mm, 1000m^Two/
An experiment was conducted in the same manner as in Example 2 except that g) was used.
Was. The number of bacteria after 2 hours is 7 × 10⁶CFU / ml.

[0023]

EFFECTS OF THE INVENTION The sterilizing apparatus for circulating type hydroponic cultivation apparatus and the hydroponic cultivation apparatus using the same remove the waste products (water-soluble organic matter) discharged from the roots, and further Can suppress the propagation of pathogens that cause diseases such as root rot,
As a result, it is not necessary to replace the culture solution or the number of replacements can be drastically reduced, and the consumer's pesticide-free request can be answered.
It provides enormous industrial benefits.

[Brief description of drawings]

FIG. 1 is a schematic diagram in which a fixed-bed type activated carbon filling tank having a sterilizing function is installed in a general circulation-type hydroponic cultivation apparatus that can be used in the present invention.

FIG. 2 is a schematic diagram of a circulating-type nutrient solution device of the present invention in which an activated carbon filling tank is a fluidized bed type and is adjacent to a culture solution tank.

[Explanation of symbols]

1 ... cultivation bed, 2 ... liquid supply pump, 3 ... culture liquid tank,
4 ... Topdressing device 5 ... Activated carbon filling tank having sterilization function, 6 ... Liquid supply pipe, 7 ...
Waste liquid pipe, 8 ... Pump, 9 ... Activated carbon filling tank (fluidized bed) 10
… Titanium dioxide coated glass tube 11… UV lamp

Claims (6)

[Claims] 1. A sterilizer for a circulating-type hydroponic cultivation apparatus using activated carbon. 2. The sterilizer for a circulation type hydroponic device according to claim 1, wherein the activated carbon is silver-impregnated activated carbon. 3. A sterilizer for a circulating-type nutrient solution cultivator according to claim 1, which has an ultraviolet irradiation device and a titanium dioxide tank. 4. The sterilizer for a circulating nutrient solution cultivator according to claim 1, wherein the activated carbon is titanium dioxide surface-adhered activated carbon and has an ultraviolet irradiation device. 5. A circulating-type hydroponic cultivation apparatus having the sterilizing apparatus according to any one of claims 1 to 4. 6. A nutrient solution sterilizing method using the sterilizing apparatus according to claim 1.