JP3150370B2 - Electrolytic treatment method for treated water containing microorganisms - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for electrolytically treating water to be treated, which contains various microorganisms and an effective chlorine component, in order to suppress various performance deteriorations caused by the microorganisms, particularly in drinking water. Regarding the method, more specifically, only the effective chlorine component which is required to remain in the drinking water among the microorganisms and the effective chlorine component in the water to be treated such as drinking water by electrolytically treating the water to be treated such as drinking water. And a method for providing clear drinking water or the like.

[0002]

2. Description of the Related Art Drinking water is supplied from a water source such as a reservoir to a water purification plant, sterilized with a disinfectant, and then supplied to households and restaurants through a water supply system. The sterilization of drinking water is generally performed by treatment with chlorine gas. According to the chlorination, the sterilization of drinking water is performed relatively well, but foreign substances are mixed in the drinking water processed by the influence of residual chlorine. It has been reported that such discomfort is caused and the mellowness of natural water is impaired, and that organic chlorine compounds represented by trihalomethane are produced, which is not preferable for human health. Drinking water is directly linked to human health, and it is essential to sterilize bacteria contained in it and prevent the growth of fungi, that is, kill most or all of the microorganisms. The method using chlorine is mainly used, but a sterilization method other than the chlorine method has been proposed in order to eliminate the above-mentioned disadvantages caused by the chlorine method.

For example, a method has been proposed in which the drinking water is subjected to an ozone addition treatment or an activated carbon adsorption treatment to reform the drinking water. However, when the drinking water to be treated is, for example, water from a water purification plant, the treatment amount is enormous. There is a disadvantage that it is not economically viable. In addition, there is a problem that even after treatment at a water purification plant, the microorganisms propagate again before reaching the faucet at the end. However, in tap water sterilization in urban areas, since the raw water such as river water and lake water is contaminated with various organic substances and the like, chlorine more than necessary for sterilizing microorganisms will be added, as described above. There is an adverse effect of producing organic halides and the like. Conventionally, in order to prevent these phenomena, various chemicals such as a fungicide and a precipitation inhibitor have been introduced into the water to be treated and various filters have been installed in the middle of the piping. It has been pointed out that adverse effects on the water to be treated due to residual chemicals and problems in the cost of using chemicals have been pointed out. Further, there is a problem in that antibacterial action against the added drug occurs after a while, and it becomes necessary to examine the next drug or to supply a drug in a larger amount than necessary. Some drinking water is temporarily stored in a water storage tank or the like, such as a cup-type vending machine, and is supplied with water as needed. This type of drinking water may be stored in a storage tank for several days, during which fungi may grow and become unsuitable as drinking water when used for drinking.
However, in these waters, no appropriate measures against the propagation of the fungus are taken, and soft drinks or the like that are not preferable for human health may be sold or provided.

[0004]

As described above, microorganisms may be contained in drinking water such as tap water or water stored in cup-type vending machines. A method for sterilizing the drinking water or the like by the treatment was proposed. According to this method, the microorganisms in the drinking water are sterilized with almost 100% efficiency, and the effective chlorine component often contained in the drinking water can be converted into chloride ions to remove the so-called scent of the drinking water. This is an excellent method for treating drinking water and the like. However, laws and regulations require that drinking water, especially tap water, contain 0.1 ppm or more of an available chlorine component. When the drinking water or the like is treated by the electrolysis, the microorganisms are almost completely sterilized and the available chlorine component is almost completely removed, so that there is a problem that it is not possible to provide drinking water conforming to laws and regulations.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned drawbacks of the prior art, to treat microorganisms almost completely, and to produce drinking water containing an effective chlorine component of a predetermined value or more. It is an object of the present invention to provide an electrolytic treatment method.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method for treating a treated water containing microorganisms and an effective chlorine component by contacting the treated water with a fixed-bed type three-dimensional electrode and performing an electrolytic treatment to sterilize the microorganisms. An electrolytic treatment method for treated water containing microorganisms, wherein treated water is treated by bringing the treated water into contact with a flat electrode.

Hereinafter, the present invention will be described in detail. In the electrolytic treatment using the fixed-bed type three-dimensional electrode according to the present invention, microorganisms in the water to be treated such as tap water can be sterilized to provide the water to be treated containing almost no microorganisms. Is also converted to a substance having no bactericidal activity, such as chloride ions. Since no microorganisms are contained in the water to be treated, there is no problem even if there is no effective chlorine component, but according to laws and regulations, drinking water is required to contain a certain value or more of the available chlorine component. Therefore, even in the case of drinking water, which has virtually no problem, it cannot be used for drinking in the general society. In the present invention, in order to solve this problem, treated water such as drinking water containing a microorganism and an effective chlorine component is treated with a fixed-bed type three-dimensional electrode and treated with water that does not contain a microorganism and an effective chlorine component. After that, the water to be treated is brought into contact with a flat electrode to convert the remaining chlorine ions into an effective chlorine component having a specified value or more, thereby providing drinking water or the like that conforms to laws and regulations.

[0008] The microorganisms of the present invention include bacteria (bacteria), fungi, molds (fungi), Escherichia coli, yeast, deformed fungi, single-celled algae, protozoa, viruses, and the like. Chlorate ions, chlorine gas and the like are included. Further, the water to be treated of the present invention is intended for drinking water to be ingested by the human body, food treated water, water storage in a water supply device, etc., and drinking water flows out of a tap and is discharged from a faucet of a household or a restaurant. Includes tap water, etc., and treated food water includes fresh water washing water and water contained in water-containing foods such as tofu, etc.Water supply water includes cup-type vending machine water storage and bank lobbies, This includes the storage of water in foot-operated water supplies installed on platforms, trains, ships, and the like. In the present invention, it is necessary to first bring the microorganisms and available chlorine components in the water to be treated into contact with the fixed-bed type three-dimensional electrode and then with the plate-type electrode. The fixed-bed type three-dimensional electrode and the flat plate type electrode may be housed in the same electrolytic cell or may be installed in separate electrolytic cells. In the former case, both electrodes are separated by an appropriate insulating member. It is necessary to prevent an electrical short circuit from occurring.

When the water to be treated is brought into contact with the fixed-bed type three-dimensional electrode, the microorganisms in the water to be treated come into contact with the fixed-bed type three-dimensional electrode, that is, a dielectric or particles for forming a fixed bed, which will be described later, by liquid flow. It is considered that a strong oxidation-reduction reaction is generated in the microbial cells by receiving a high potential energy supply from the surface thereof, and the activity is weakened or the microbe itself is killed and sterilization is performed. Simultaneously with the sterilization of the microorganism, the conversion of the available chlorine component in the water to be treated into chloride ions is performed on the cathode surface of the three-dimensional electrolytic cell. Hypochlorite ion, which is the main component of the available chlorine component in the water to be treated, is converted into chlorine ion and water according to the following equation (1). ClO ⁻ + 2H ⁺ + 2e ⁻ → Cl ⁻ + H ₂ O (1)

[0010] In addition to tap water, trace ions and dissolved substances such as calcium ions and magnesium ions other than the above-mentioned microorganisms and available chlorine components are present as clusters having hydrated water around the hydrated water. Is one of the causes of loss of mellowness. When the drinking water or the like is subjected to electrolytic treatment by the method of the present invention, in addition to sterilizing microorganisms and decomposing available chlorine components, the ions in the drinking water migrate or move at high speed in the liquid according to the potential gradient, and the cluster can move. Instead, a huge cluster is destroyed, or ions having hydration water come into contact with the cathode side and are destroyed as described above, so that the number of the hydration water is greatly reduced, and a reforming effect of drinking water and the like also occurs. Furthermore, the calcium ions and magnesium ions also contribute to the deterioration of the taste of drinking water. However, when the drinking water is subjected to the electrolytic treatment of the present invention, these ions precipitate as hydroxides thereof on the cathode side. Since it is removed from drinking water, the taste of drinking water is further improved. The electrode used for sterilizing microorganisms and decomposing available chlorine components in the method of the present invention is a fixed-bed type three-dimensional electrode, which has an enormous surface area to increase the contact area between the electrode surface and the water to be treated. This is advantageous in that the size of the apparatus can be reduced and the efficiency of the electrolytic treatment can be increased. The fixed-bed type three-dimensional electrode may be incorporated in an electrolytic cell as a bipolar electrode to constitute a bipolar electrolytic cell, or may be incorporated as a single electrode to constitute a monopolar electrolytic cell.

When the fixed-bed type three-dimensional electrode in the method of the present invention is incorporated into an electrolytic cell, the electrolytic cell generally includes a power supply electrode in addition to the three-dimensional electrode which causes a polarization phenomenon and functions as an electrode. Has a shape corresponding to the electrolytic cell used above, and when using a fixed bed type bipolar electrolytic cell,
A porous material through which the water to be treated can pass, for example, granular, spherical, felt, woven, activated carbon having a shape such as a porous block, graphite, carbon-based material such as carbon fiber, or the same shape. Nickel, copper, stainless steel, iron, a plurality of preferably granular, spherical, fibrous, felt, woven, formed of a metal material such as titanium, a material obtained by further coating the metal material with a noble metal, A porous block, porous plate, or sponge-like dielectric is placed in a DC electric field, and a DC voltage is applied between the power supply electrodes formed of a flat plate, an expanded mesh, a perforated plate, or the like provided at both ends. Or 10
A fixed-bed bipolar electrode containing a three-dimensional electrode formed by applying an AC voltage of less than Hz to polarize the dielectric and form an anode and a cathode at one end and the other end of the dielectric, respectively. In addition, a three-dimensional material functioning independently as an anode or a cathode can be provided so as not to be alternately short-circuited and electrically connected to form a fixed-bed bipolar electrode.

Activated carbon, graphite,
When using a carbon-based material such as carbon fiber and treating water to be treated while generating oxygen gas from the anode, the dielectric may be oxidized by oxygen gas and dissolved as carbon dioxide gas. In order to prevent this, a porous metal material which is usually used as an insoluble metal electrode by coating a platinum group metal oxide such as iridium oxide or ruthenium oxide on a base material such as titanium on the side of the dielectric that is positively polarized May be placed in contact with each other so that oxygen is generated mainly on the metal material. When a carbon-based material (carbonaceous three-dimensional electrode) is used as the dielectric (three-dimensional electrode), it is preferable that the average pore diameter is 25 to 125 μm. When accommodating a carbonaceous three-dimensional electrode in an electrolytic cell to treat water to be treated,
The properties of the carbonaceous three-dimensional electrode affect the ease of flow of the water to be treated or the electrolytic voltage. The opening diameter of the carbonaceous three-dimensional electrode also has a relatively strong effect. If the opening diameter of the carbonaceous three-dimensional electrode is large, the water to be treated easily passes through the electrolytic cell without contacting the electrode. Efficiency decreases. Conversely, if the opening diameter is too small, the water to be treated cannot flow through the carbonaceous three-dimensional electrode, causing an increase in the electrolysis voltage and a pressure loss of the liquid flow in the electrolysis tank.

A carbonaceous three-dimensional electrode having a desired opening diameter can be manufactured as follows. For example, when forming a three-dimensional electrode by sintering carbon-based particles, by adjusting the particle size of the carbon-based particles to be used, by adjusting the opening diameter of the prepared three-dimensional electrode, an arbitrary opening diameter Having a sintering temperature of 1000 to 4000C, preferably about 3800C. In the case of a felt-like carbonaceous three-dimensional electrode, a three-dimensional electrode having an arbitrary average opening diameter can be obtained by adjusting the pressure at the time of molding and the diameter of the carbon fiber used. In these cases, the relationship between the carbon-based particles and the pore size and the relationship between the molding pressure and the pore size can be empirically obtained. Also, as another type of fixed-bed type bipolar electrolytic cell, for example, a power supply anode and a cathode are installed in a cylindrical electrolytic cell body, and a large number of conductive electrodes functioning as three-dimensional electrodes are provided between the power supply electrodes. There is an electrolytic cell in which particles for forming a fixed bed and insulating particles made of a synthetic resin or the like having a smaller number of particles than the particles for forming a fixed bed are almost uniformly mixed. In the electrolytic cell, when a potential is applied by applying a current between both power supply electrodes, the fixed bed forming particles are polarized in the same manner as the dielectric, and one end thereof is positively charged and the other end is negatively charged, thereby forming each fixed bed. A potential is generated in the particles for use, and a function of sterilizing microorganisms in the water to be treated is imparted to each particle. The insulating particles have a function of preventing the two power supply electrodes from being electrically connected by the conductive fixed bed forming particles to cause a short circuit.

When a monopolar fixed-bed electrolytic cell is used, the above-mentioned dielectric or one of the three-dimensional materials which independently function as an anode or a cathode can be used with or without a diaphragm. Or a plurality of dielectrics or the three-dimensional material are placed in a single electrolytic cell at the same electrolytic potential. Regardless of which type of electrode is used, the efficiency of the water to be treated decreases if there is a gap in the electrolytic cell through which the water to be treated flows without allowing the liquid to come into contact with the electrode, dielectric or fine particles. Therefore, it is desirable to arrange the electrodes and the like so that the flow of the water to be treated in the electrolytic cell does not contact the electrodes and does not cause a short path.

[0015] Even if the anode chamber and the cathode chamber are formed by partitioning the inside of the electrolytic cell with a diaphragm, energization can be carried out without using a diaphragm. Alternatively, when the distance between the dielectric material and the electrode or between the dielectric materials is reduced, a mesh spacer made of, for example, an organic polymer material is inserted between both electrodes or between the dielectric materials as an electrically insulating spacer to prevent a short circuit. can do. When a diaphragm is used, it is desirable to use a porous material having an opening ratio of 10% or more and 95% or less, preferably 20% or more and 80% or less, so as not to hinder the movement of the water to be circulated. The diaphragm must have at least micropores with a pore size that allows the water to be treated to permeate. The water to be treated, which has been subjected to electrolytic treatment in contact with such a fixed-bed type three-dimensional electrode to sterilize microorganisms and decompose the available chlorine component, is then brought into contact with a flat-plate electrode to generate the available chlorine component. Effective chlorine components such as hypochlorite ions and chlorine gas are generated again from the chlorine ions thus obtained. As the material of the flat electrode, a conventionally used material may be used as it is. For example, a plate-shaped platinum group oxide-coated titanium material (dimensionally stable electrode) or nickel material is used as the anode, and a plate-shaped material is used as the cathode. Stainless steel, carbon, or the like can be used.

As described above, this flat electrode may be installed in the same electrolytic cell as the fixed-bed type three-dimensional electrode, or may be installed in a separate electrolytic cell. Electric conductivity of tap water and groundwater
When the water to be treated is used at about 500 μS / cm and the two electrodes are installed in the same electrolytic cell, a short circuit may occur between the two electrodes and a leakage current may flow. Therefore, in this case, it is desirable to take measures to prevent the generation of the leakage current. For example, an insulating material having an opening ratio that does not hinder the flow of the water to be treated, preferably an insulating material having an opening ratio of 30% or less, is used. Isolate electrodes to prevent short circuit. The flat electrode has a small surface area and usually has a current density of 1.0 A / dm ² or more, which is larger than the current density of the fixed-bed three-dimensional electrode. At this current density, the reverse reaction of the formula (1) occurs at the anode. Effective chlorine components such as hypochlorite ions are generated again. At this time, it is possible to appropriately set the concentration of the effective chlorine component to be generated by controlling the current flowing within the range of the current density, and to provide the water to be treated having the optimum concentration according to the legal value.

Next, preferred examples of the electrolytic cell that can be used in the present invention will be described with reference to the accompanying drawings. However, the electrolytic cell that can be used in the present invention is not limited to this electrolytic cell. FIG. 1 is a schematic longitudinal sectional view showing an example of a single electrolytic cell accommodating a bipolar fixed bed electrode and a flat electrode which can be used as an electrolytic cell in the method of the present invention. At the center of the bottom plate, supply the water to be treated 1
A cylindrical electrolytic cell main body 3 having a water outlet 2 at the center of the top plate and a lower three-dimensional electrode formed by an insulating plate 5 made of an insulating material having a through hole 4 formed at the center for flowing the water to be processed. The chamber is divided into a chamber 6 and an upper flat electrode chamber 7.
The electrolytic cell main body 3 is preferably formed of an electrically insulating material that can withstand long-term use or re-use. Particularly, synthetic resins such as polyepichlorohydrin, polyvinyl methacrylate, polyethylene, polypropylene, polyvinyl chloride, and polyvinyl chloride Ethylene, phenol-formaldehyde resin, polyacrylonitrile resin and the like can be preferably used. In the vicinity of the upper end and the lower end of the interior of the three-dimensional electrode chamber 6, a meshed power supply anode 8 and a power supply cathode 9 are respectively provided.
Is provided. In the illustrated example, three spongy fixed floor type three-dimensional electrodes are provided between the power supply electrodes 8 and 9.
10 are laminated, and between the three-dimensional electrodes 10 and the three-dimensional electrodes
Four mesh-shaped diaphragms or spacers 11 are sandwiched between 10 and the power supply electrodes 8 and 9. Each of the three-dimensional electrodes 10 is in close contact with the inner wall of the electrolytic cell main body 3 and does not pass through the inside of the three-dimensional electrode 10, and the leakage flow of the water to be treated flowing between the three-dimensional electrode 10 and the side wall of the electrolytic cell main body 3 is minimized. It is arranged to be less. Reference numeral 12 denotes a porous metal material such as an insoluble electrode provided in close contact with the three-dimensional electrode 10 on the side of positive polarization.

A plate-type anode 13 and a plate-type cathode 14 located vertically are installed in the plate-type electrode chamber 7, and their effective current density becomes larger than the effective current density of the fixed-bed-type electrode 10 when energized. To do. The fixed floor type three-dimensional electrode 10 and the plate type electrodes 13 and 14 may be energized by separate power sources, respectively, or a single power source may be used by common wiring to energize both electrodes. When current is supplied to the three-dimensional electrode chamber 6 of the electrolytic cell having such a configuration while supplying water to be treated as indicated by an arrow from below, the fixed-bed type three-dimensional electrode 10 has its lower surface fixed as shown in the figure. The upper surface is negatively polarized to form a porous anode on the lower surface of each three-dimensional electrode 10, and the water to be treated comes into contact with the porous anode to sterilize microorganisms. Further, the water to be treated comes into contact with the porous cathode on the upper surface to remove calcium, magnesium, iron ions and the like as hydroxides thereof, and to remove available chlorine components such as hypochlorite ions and chlorine gas. It is converted to chloride ions according to the above formula (1) and supplied to the flat electrode chamber 7 through the through-hole 4 in a state where microorganisms and available chlorine components are almost not contained. In the flat-plate type electrode chamber 7, chlorine ions generated in the fixed-bed type three-dimensional electrode chamber 6 are oxidized or reduced to be converted into hypochlorite ions or chlorine gas, and an effective chlorine component conforming to laws and regulations is converted. It is taken out from the treated water outlet 2 as drinking water or the like, and is used for a predetermined application.

FIG. 2 relates to the improvement of the electrolytic cell of FIG. 1, and the same members as those of FIG. The three-dimensional electrode chamber 6 and the plate-shaped electrode chamber 7 are defined by a separator plate 5 'made of an insulating material having a centrally formed through-hole 4' for flowing the water to be treated having a diameter larger than the through-hole 4 of FIG. A cylindrical connecting rod 15 is inserted into the through hole 4 '. The lower end of the connection rod 15 is connected to the power supply anode 8 in the three-dimensional electrode chamber 6, and the upper end of the rod 16 is a mesh-like or plate-like one disposed parallel and separated in the flat-type electrode chamber 7. Of the anode 13 'and the cathode 14', it is connected to the cathode 14 'located below. When this electrolytic cell is used, as in the case of FIG. 1, the water to be treated comes into contact with the porous anode of the three-dimensional electrode 10 to sterilize microorganisms. Further, the water to be treated contacts the porous cathode on the upper surface, and calcium and the like are precipitated and removed as hydroxides and the like, and the water is passed through in a state where it contains almost no effective chlorine component such as hypochlorite ion. 4 '
Is supplied to the flat-plate-type electrode chamber 7. Electrolysis of the water to be treated is similarly performed in the flat electrode chamber 7, and is taken out from the water to be treated outlet 2 as drinking water or the like having an effective chlorine component conforming to the regulations of the law and used for a predetermined application. .

FIG. 3 is a schematic diagram showing a state in which the electrolytic cell of FIG. 1 is used for reforming water stored in a cup-type vending machine. Tap water or the like serving as dilution water for the cup-type vending machine is supplied to a box-shaped storage tank 17 for the cup-type vending machine after solid impurities are removed by a filter 16 in advance. The tank
The stored water 18 in the tank 17 is circulated through a circulation line 19 to which the electrolytic cell 3 is connected. In the three-dimensional electrode chamber 6 of the electrolytic cell 3, sterilization of microorganisms and removal of available chlorine components are performed. After a fixed amount of available chlorine component is generated again, the storage tank 17 is returned. Therefore, the storage water 18 in the tank 17 is always compliant with laws and regulations as drinking water containing no microorganisms and containing a predetermined amount of available chlorine components. The water storage 18 in the storage tank 17 is supplied to the paper cup 21 by opening the cock 20, mixed with the concentrated undiluted solution supplied separately, and sold as soft drinks or the like.

FIG. 4 is a schematic vertical sectional view showing another example of an electrolytic cell which can be used as an electrolytic cell in the method of the present invention. At the center of the bottom plate, the treated water supply port 31 and at the center of the top plate, the treated water outlet
A short cylindrical three-dimensional electrode type electrolytic cell 33 each having 32
Inside, a fixed-bed type three-dimensional anode 34 and a flat-plate type cathode 35, which are the same as the fixed-bed type three-dimensional electrode of FIG. 1, are provided to constitute a monopolar electrolytic cell. The treated water outlet 32 of the three-dimensional electrode type electrolytic cell 33 has a treated water supply port 37 of a flat type electrode type electrolytic cell 36.
Are connected to each other, and a plate-type anode 38 and a plate-type cathode 39 positioned in the vertical direction are installed in the plate-type electrode-type electrolytic cell 36, and the water to be treated in the plate-type electrode-type electrolytic cell 36 is treated. It is taken out from the treated water outlet 40. In the example shown in the drawing, as in the case of FIG. 1, it is possible to produce drinking water or the like that does not contain microorganisms containing a predetermined concentration of available chlorine component. In addition, the fixed bed electrode 34 and the plate electrodes 38 and 39 are separate. No short circuit occurs because it is installed in the electrolytic cell.

[0022]

EXAMPLES Next, examples of the treatment of the water to be treated by the method of the present invention will be described. However, the present examples do not limit the present invention.

Example 1 Transparent rigid polyvinyl chloride resin height 80
The electrolytic treatment of the water to be treated was carried out using the electrolytic tank shown in FIG. In the fixed-bed type electrode chamber of the electrolytic cell, three fixed-bed-type three-dimensional electrodes having a diameter of 38 mm and a thickness of 10 mm made of a carbon fiber and made of a iridium oxide-coated titanium material and having a close contact with each other are provided with an aperture ratio. A diameter of 80% made of titanium sandwiched between four polyethylene resin diaphragms having a diameter of 38 mm and a thickness of 1.2 mm, and platinum on the upper and lower ends of the diaphragms respectively plated with platinum.
A mesh-shaped power supply anode and a power supply cathode having a thickness of 38 mm and a thickness of 1.0 mm were placed in contact with each other.

The flat electrode chamber of the electrolytic cell has a length of 30 mm,
Anode consisting of dimensionally stable electrodes 30 mm wide and 1.0 mm thick, and 30 mm long, 30 mm wide and 1.0 m thick made of titanium
m of cathodes were placed 5.0 mm apart from each other. Both electrode chambers are made of vinyl chloride resin and have a diameter of 40mm and a diameter of 10m at the center.
m was defined by a separator having through holes formed therein. The two electrodes are energized by separate power supplies, a voltage of 16 V is applied to the fixed-bed electrode chamber so that the effective current density is 0.15 A / dm ^2, and a voltage of 2.5 V is applied to the flat-type electrode chamber. And its effective current density was 3.5 A / dm ² . Microorganisms were added to tap water, and 3.0 liters of test water having a microorganism count of 3400 / ml was treated as water to be treated. The inside of the electrolytic cell was a fixed-bed type electrode chamber and a flat type electrode chamber at a flow rate of 1.2 liters / minute. It passed and electrolysis was performed. After introducing the water to be treated taken out of the electrolytic tank into the storage tank, it was again supplied to the electrolytic tank and passed through the electrolytic tank a plurality of times to measure the number of microorganisms and the available chlorine component in the storage tank after a predetermined time had elapsed. However, it was as shown in Table 1.

[0024]

Example 2 The water to be treated was treated in the same manner as in Example 1 except that the separator of the electrolytic cell was removed. The results are shown in Table 2. From Table 2, the number of microorganisms slightly increased after passing through the electrolytic cell, which is presumed to be due to a short circuit of the electrolytic current between the fixed-bed electrode and the flat-plate electrode via the water to be treated.

[0025]

Comparative Example 1 Water to be treated was treated under the same conditions as in Example 1 except that no current was applied to the flat electrode, and the number of microorganisms and the available chlorine component before and after passing through the electrolytic cell were measured. It was right. From Table 3, it can be seen that the effective chlorine component is hardly contained in the water to be treated taken out of the electrolytic cell unless the flat electrode is used.

[0026]

[0027]

Embodiment 3 The electrolytic treatment of the water to be treated was carried out using the electrolytic bath shown in FIG. In a fixed-bed electrode type electrolytic cell made of a transparent cylindrical polyvinyl chloride resin having an inner diameter of 40 mm and a height of 30 mm, a fixed-bed three-dimensional anode made of carbon fiber and having a diameter of 38 mm and a thickness of 20 mm, and a titanium Made of 38mm diameter and 1.
A 0 mm plate cathode was installed. In a box-type flat plate type electrolytic cell of 20 mm in height, 40 mm in width and 40 mm in height, 15 m in length
m, 35 mm wide and 1.0 mm thick anode consisting of dimensionally stable electrodes, and titanium 15 mm long, 35 mm wide and 1.
The cathodes of 0 mm were placed sufficiently separated from each other. The two electrolytic cells are energized by separate power supplies, and a voltage of 5.5 V is applied to the fixed-bed type three-dimensional electrode type electrolytic cell.
0.25 A / dm ^2, and a voltage of 2.5 V was applied to a flat electrode type electrolytic cell, and the effective current density was 1.5 A / dm ^2.
dm ² . The same water to be treated as in Example 1 was passed through both electrolytic cells, and an electrolytic treatment was performed in the same manner as in Example 1. The water to be treated taken out of the electrolytic cell was supplied to the electrolytic cell again, passed through the electrolytic cell a plurality of times, and the number of microorganisms and the available chlorine component in the storage tank after a predetermined time had elapsed were measured. Was.

[0028]

[Table 4]

[0029]

According to the method of the present invention, the water to be treated containing microorganisms and effective chlorine components is brought into contact with a fixed-bed type three-dimensional electrode to carry out electrolytic treatment and sterilization of the microorganisms. An electrolytic treatment method for water to be treated containing microorganisms, wherein the treatment is carried out by contacting with a mold electrode (claim 1). The conventional method of electrochemically treating water to be treated containing microorganisms not only sterilizes the microorganisms but also decomposes available chlorine components that may be contained in the water to be treated. Since substantially no microorganisms are contained in the water to be treated thus obtained, no substantial harm is caused even if no effective chlorine component is contained, but when the treated water to be treated is used as drinking water. Must contain more than a certain amount of available chlorine components according to the provisions of laws and regulations.

Therefore, in the case where drinking water is produced by performing a reforming treatment using microorganisms and available chlorine components as the water to be treated, the microorganisms are completely sterilized and the available chlorine components are partially decomposed to obtain a small amount of available chlorine. Ideally, the chlorine component remains.
However, in practice, it is almost impossible to leave a desired amount of available chlorine component. The present invention provides an electrolytic treatment of water to be treated containing microorganisms and available chlorine components using a fixed-bed type three-dimensional electrode to sterilize microorganisms and decompose available chlorine components almost completely. A predetermined amount of an effective chlorine component is again generated in the water to be treated by electrolyzing the water to be treated containing chloride ions, which are decomposition products of the components, with a flat electrode, and drinking water and the like that comply with laws and regulations are obtained. It is what made it possible to obtain.

In particular, water from a cup-type vending machine, a lobby, a platform, and a water supply device in a train or a ship is stored in a storage tank and supplied as needed, so that the water is often stored in the tank for a long period of time. It is required to contain the effective chlorine component in a specified amount or more as described above. When the present invention is applied to the water storage of the cup-type vending machine or the water storage of a lobby or a platform water supply (claim 2), sterilization of the propagated microorganisms and generation of the effective chlorine component can be performed at the same time. Soft drinks and the like using clear water as a raw material can be provided.
The fixed bed type three-dimensional electrode and the flat plate type electrode may be installed in the same electrolytic cell or in separate electrolytic cells, but may be installed in the same electrolytic cell to reduce the installation area. Preferred (claim 3). However, when both electrodes are installed in the same electrolytic cell, it is desirable to take measures to prevent a short circuit between the two electrodes, for example, by using an insulating separator having a through hole that does not hinder the flow of the water to be treated. An electrode chamber containing the electrodes is defined.

The decomposition of the available chlorine component and the generation of the available chlorine component from the decomposition product may occur simultaneously. In the present invention, the decomposition of the available chlorine component is carried out in a fixed-bed type three-dimensional electrode chamber. It is necessary to produce available chlorine components in the chamber. The two reactions are greatly affected by the current density of the electrode. At a low current density, the available chlorine component is easily decomposed, and at a high current density, the available chlorine component is easily generated. Generally, a fixed-bed type three-dimensional electrode has a high surface area and a flat plate type electrode has a low surface area.
Therefore, if the normal fixed-bed type three-dimensional electrode and the flat-plate type electrode are used as they are, the current density of the fixed-bed type three-dimensional electrode is low and the effective chlorine component is decomposed, and the current density of the flat-type electrode is high and the effective chlorine component is generated. As a result (claim 4), it is possible to obtain drinking water or the like having a desired effective chlorine component concentration and containing almost no microorganisms.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view showing an example of a single electrolytic cell containing a bipolar fixed-bed electrode and a flat electrode that can be used as an electrolytic cell in the method of the present invention.

FIG. 2 is a schematic longitudinal sectional view showing an electrolytic cell according to an improvement of the electrolytic cell of FIG.

FIG. 3 is a schematic diagram showing a state in which the electrolytic cell of FIG. 1 is used for a reforming treatment of water stored in a cup-type vending machine.

FIG. 4 is a schematic longitudinal sectional view showing another example of an electrolytic cell that can be used as an electrolytic cell in the method of the present invention.

[Explanation of symbols]

3 ・ ・ ・ Electrolyzer main body 4 ・ ・ ・ Through hole 5 ・ ・ ・ Separator plate
6 ... three-dimensional electrode chamber 7 ... flat plate electrode chamber 8 ... anode for power supply 9 ...
Cathode chamber for power supply 10 ・ ・ ・ Fixed floor type electrode 13 ・ ・ ・ Plate type anode 14 ・ ・ ・ Plate type cathode 17 ・ ・ ・ Storage tank 18 ・
・ ・ Water storage 21 ・ ・ ・ Paper cup 33 ・ ・ ・ 3D electrode type electrolytic cell 34 ・ ・ ・ 3D electrode 36 ・ ・ ・ Plate type electrode type electrolytic cell 38 ・ ・ ・ Plate type anode 39 ・ ・ ・ Plate type cathode

──────────────────────────────────────────────────続 き Continued on the front page (56) References JP-A-62-262787 (JP, A) JP-A-54-99340 (JP, A) JP-A-2-2977697 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) C02F 1/46-1/48 G07F 13/00

Claims (4)

(57) [Claims] Claims: 1. A treated water containing a microorganism and an effective chlorine component is brought into contact with a fixed-bed type three-dimensional electrode to perform an electrolytic treatment to sterilize the microorganism, and then the treated water is brought into contact with a flat electrode. A method for electrolytically treating water to be treated containing microorganisms, the method comprising: 2. The method according to claim 1, wherein the water to be treated is water in a cup-type vending machine and / or water in a water supply device. 3. The method according to claim 1, wherein the fixed bed type three-dimensional electrode and the flat plate type electrode are provided in a single electrolytic cell. 4. The method according to claim 1, wherein the effective current density of the fixed-bed type three-dimensional electrode is smaller than the effective current density of the flat-plate type electrode.