JP2003080264A - Liquid treatment method and equipment for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid treatment method capable of obtaining a stable electric discharge state over the entire part between electrodes in improving the quality of a liquid existing between the electrodes by supplying impulsive electric power to the electrode pair and equipment capable of realizing this method. SOLUTION: In the liquid treatment method for improving the quality of the liquid successively supplied between the electrodes by disposing at least one set of the electrode pair and forming the electric discharge state between the electrodes by applying the high-voltage pulses to the electrode pair, gas and/or solid from the liquid on the upstream side of an electric discharge state forming region are removed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to (1) biological treatment of organic waste liquid discharged from a sewage treatment process in a sewage treatment plant or a human waste treatment plant, or a wastewater treatment process of a food factory or a chemical factory. Aerobic treatment or anaerobic treatment, (2) sterilization of treated water in the process of producing waste water (including organic substances other than the above) of each plant, clean pure water, tap water, food, drinking water, etc.・ Sterilization treatment, decolorization treatment, deodorization treatment, or (3) Dioxins that appear during sterilization / sterilization treatment, decolorization treatment, deodorization treatment of the above-mentioned various liquids, or when leaching water from leach incinerator. The present invention relates to a method for treating a liquid which is applied to a decomposition treatment of a hardly decomposable substance such as an endocrine disrupter or PCB, and an apparatus used for carrying out such a treatment method.

[0002]

2. Description of the Related Art In the various uses shown in (1) to (3) above, various methods such as activated carbon treatment, ozone treatment, and membrane treatment have hitherto been used as methods for reusing water and removing trace contaminants. Is known and is being put to practical use. However, the activated carbon treatment can adsorb and remove organic pollutants, but has no bactericidal effect and requires frequent replacement of the activated carbon. In ozone treatment, decolorization,
Although it is excellent in deodorizing and sterilizing effects, it has a problem of secondary treatment due to residual ozone. Further, in the membrane treatment, although water treatment is excellent from the viewpoint of removing contaminants and the like, there are problems that maintenance is complicated and the cost is high, and waste is generated.

The present inventors have been researching the improvement of the above-mentioned water treatment technology for some time, and have proposed a technology such as JP-A No. 11-253999 as part of the research. This technique is, for example, as a method of killing harmful bacteria contained in a liquid to purify the liquid, or a fouling component composed of bacteria contained in the liquid (processing liquid) or dead bodies thereof. As a method of modifying the fouling component into a state in which aerobic microorganisms can be easily biochemically treated to reduce the volume of the liquid, the liquid is subjected to high-voltage pulse discharge treatment and / or electric field pulse application to remove the liquid. It is something to process. This will be described with reference to the drawings.

FIG. 1 shows a reforming device 18 for applying high-voltage pulse discharge and / or electric field pulse to the liquid, which comprises a reforming tank 3 and a power source 4 (arrows A and B in the figure). Indicates the flow of pollutants). A rod-shaped electrode (+ electrode) 5 and a flat plate electrode (-electrode) 6 connected to the power source 4 are arranged in parallel so as to be immersed in the fouling substance (sludge) in the reforming tank 3. The sludge in the reforming tank 3 can be electrically regarded as a dielectric having a certain dielectric constant, and a voltage is applied to the electrodes 5, 6 while the dielectric is filled between the electrodes 5, 6. When positive and negative charges are respectively transferred to 6, an electric field is formed in the dielectric (sludge), and when the strength of this electric field exceeds a certain level, dielectric breakdown occurs and discharge occurs between electrodes 5 and 6. To do.
By adopting such a configuration, sludge can be solubilized,
It has become possible to lower the molecular weight (modify).

[0005]

The present inventors have also found that
We have also developed a liquid treatment device that discharges and modifies various liquids, and since its technical significance was recognized, we have filed a patent application (Japanese Patent Application No. 2000-186493). This will be described with reference to the drawings.

FIG. 2 is a schematic explanatory view showing an example of an arrangement state of electrodes and a discharge state in the reforming tank 3 described above,
In the figure, 3 is a reforming tank, 25 is a rod-shaped electrode, 26 is a ring-shaped electrode, 27
Is a high voltage pulse power supply, 23 is a liquid to be treated, and 24 is a discharge. In the configuration shown in FIG. 2, the rod-shaped electrode 25 and the ring-shaped electrode 2
6 are arranged concentrically, and a pulse voltage with a steep rising is applied between the rod-shaped electrode 25 and the ring-shaped electrode 26 by the high-voltage pulse power supply 27.
Since the voltage is applied from above, an omnidirectional discharge is generated from the tip of the rod-shaped electrode 25 toward the ring-shaped electrode 26. Therefore,
Since this discharge 24 becomes a planar three-dimensional discharge, the liquid to be treated is
It has become possible to apply the discharge 24 to 23 over a wide range.

However, even with the above-mentioned structure, there are some problems to be solved. That is, in the above configuration, the discharge state between the electrodes may be non-uniform,
Even between the electrodes, there were portions where discharge was generated and portions where discharge was not generated. Then, along with this, there are cases in which the processing efficiency of the stain component decreases.

The present invention has been made in view of such a situation, and an object thereof is to stabilize when a pulsed electric power is supplied to an electrode pair to reform a liquid existing between the electrodes. It is an object of the present invention to provide a liquid treatment method capable of obtaining a discharge state across electrodes and an apparatus capable of realizing this method.

[0009]

The liquid treatment method according to the present invention, which has been able to solve the above-mentioned problems, is to provide at least one pair of electrodes and apply a high voltage pulse to the pair of electrodes to apply a high voltage pulse between the electrodes. In the liquid treatment method for reforming the liquid sequentially supplied between the electrodes by forming the discharge state in the electrode, the point is to remove gas and / or solid from the liquid on the upstream side of the discharge state forming region.

Further, the liquid processing apparatus according to the present invention which has been able to solve the above-mentioned problems is provided with at least one pair of electrodes, and a high voltage pulse is applied to the pair of electrodes to establish a discharge state between the electrodes. In the liquid processing device configured to reform the liquid sequentially supplied between the electrodes by forming the liquid, a means for removing gas and / or solid from the liquid is provided on the upstream side of the discharge state forming region. Have. In this case, it is preferable to provide means for extracting gas and / or solid from the means for removing gas and / or solid.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The present inventors have studied from various angles in order to solve the above problems. As a result, it was found that the reason why the discharge state becomes unstable is that coarse bubbles and solids are mixed in the region where the discharge is occurring.

That is, when gas (bubbles) is mixed in the liquid (liquid to be treated), the bubbles enter the discharge region, and the electric field strength at the portion where the bubbles are present increases. As a result, a state in which the discharge is locally concentrated occurs as shown in FIG. When such a condition occurs, even if the liquid to be treated passes between the electrodes, the chances of the liquid to be treated passing through a region where no discharge actually occurs increases and the substance to be discharged outside the system without being reformed. The processing liquid will increase. As a result, the treatment efficiency of the entire liquid to be treated is lowered. In addition, the size of the gas mixed in the liquid to be treated is generally non-uniform, which is also one of the factors that change the electric field strength. Furthermore, the air bubbles mixed in the liquid to be treated are aggregated and coarsen with the flow of the liquid to be treated. Even if the gas thus coarsened enters the discharge region, stable discharge cannot be maintained.

On the other hand, the same is true when solids are mixed in the liquid to be treated, and since solids usually have a lower relative dielectric constant than water, when such solids enter the discharge generation region, the electric field strength is locally increased. As a result, the discharge is concentrated and is generated at the raised portion. As a result, the discharge state in the discharge region becomes non-uniform, and the treatment efficiency of the liquid to be treated decreases.

Therefore, in the liquid processing method according to the present invention,
When reforming a liquid by applying a high voltage pulse, if operation is performed to remove gas and / or solids from the liquid on the upstream side of the discharge state forming region, stable discharge as shown in Fig. 3 (b) can be achieved. The present invention has been completed by finding that the above can be obtained.

Hereinafter, the operation and effect of the present invention will be described with reference to the drawings. However, the present invention is not limited to these illustrated examples, and any design changes can be made with the gist of the preceding and the following description. It is included in the technical scope of the present invention. In addition, the same reference numerals are given to the common components in the respective drawings to avoid redundant description.

FIG. 4 is a schematic explanatory view showing an example of the liquid processing apparatus according to the present invention. In this configuration, in the reforming tank 3 shown in FIG. 2, the flow direction of the liquid 23 to be processed (arrow direction).
A means (1) for removing gas and solids from the liquid to be treated (liquid) is provided on the upstream side of. That is, in FIG. 4, the pipe line 10 connected to the reforming tank 3 is arranged so as to have an S-shape that is lateral to the vertical direction. Therefore, when the liquid 23 to be treated flows in the pipe 10, the gas mixed in the liquid 23 to be treated is recovered at the convex portion of the pipe 10 (the portion of the S-shape that is vertically upwardly convex). Therefore, the solid from the liquid 23 to be treated can be collected in the concave portion of the conduit 10 (the portion of the S-shape that is convex vertically downward). As a result, the liquid to be treated 23 that has passed through the pipe line 10 contains almost no gas or solid, so that even if the liquid to be treated enters the discharge region, the gas or solids to be mixed in the liquid to be treated are mixed. Does not hinder the discharge state. Therefore, in the present invention, a stable discharge state can be maintained, so that the treatment efficiency of the liquid to be treated is not reduced.

Further, in the present invention, it is preferable that the gas or solid recovered from the liquid to be treated as described above is sequentially discharged out of the system. That is, when a large amount of gas is accumulated in the convex portion of the conduit 10 in FIG. 4, the flow of the liquid to be treated 23 may be deteriorated, or the trapped gas may be mixed in the discharge region along the flow of the liquid to be treated 23. is there. Further, if a large amount of solids settles in the recesses of the pipeline 10, the flow of the liquid to be treated 23 may become poor, or if solids are excessively deposited, the solid recovery efficiency may decrease. Therefore, in the liquid processing apparatus according to the present invention, it is recommended that the device for removing the gas or solid from the liquid to be processed be provided with the extracting device for discharging the gas or solid out of the system. Such a configuration will be described with reference to the drawings.

FIG. 5 is a schematic explanatory view showing another structural example of the liquid processing apparatus according to the present invention. In this example, a gas or solid extracting means is provided in addition to the structure shown in FIG. That is, the spaces 11 and 12 are provided at the ends of the convex portion and the concave portion of the conduit 10 shown in FIG. 4, respectively. Then, slits are provided in the upper part and the lower part of the space, and the space is divided by interposing a plurality of plates.

By thus providing the spaces at the ends of the convex portion and the concave portion of the conduit 10, respectively, the amount of gas or solid that can be recovered from the liquid to be treated can be increased. Since the space is divided by plates, the upper and lower plates of the space are alternately operated to efficiently remove gas and solids accumulated in the space without releasing excess liquid to be treated from the system. Can be discharged well.

Although a structure in which a gas and a solid are taken out of the system by providing a slit and a plate is shown here, other methods can of course be adopted. For example, a rotary three-way valve or the like may be provided instead of the slit and the plate.

Although FIG. 4 and FIG. 5 show the constitutional example in which both the gas and the solid mixed in the liquid 23 to be treated can be removed by arranging the pipe 10 in the S shape.
A gas or solid can be selectively removed from the liquid to be treated, if necessary. That is, when either one of the solid and the gas has been removed in advance, or when either one of them does not exist at all, it is sufficient to recover only the one that has not been removed from the liquid to be treated. Such a configuration will be described with reference to the drawings.

FIG. 6 is a schematic explanatory view showing one structural example of the liquid processing apparatus according to the present invention configured to remove only gas from the liquid to be processed, which is connected to the reforming tank 3 shown in FIG. The shape of the pipe line 8 that has become convex (U
Are arranged in a letter shape. As a result, only the gas can be efficiently removed from the liquid to be treated 23.

On the other hand, in order to intensively remove only the solids mixed in the liquid to be treated 23, as shown in FIG. 7, the shape of the pipe 9 connected to the reforming tank 3 is changed downward. It may be arranged so as to form a convex shape (a U shape).

FIG. 8 is a schematic explanatory view showing another constitutional example of the liquid treatment apparatus according to the present invention. In FIG. 8, the pipe line 13 connected to the reforming tank 3 has a linear shape (horizontal direction). The pipe line 13 is provided with spaces 11 and 12 for trapping a gas or a solid, respectively. As described above, the effect of the present invention can be sufficiently obtained also by providing the space for trapping the gas or the solid in the pipeline.

Even in this case, it is preferable to provide means for discharging the gas or solid trapped in the space as described above to the outside of the system. Further, in FIG. 8, the space 11 is directly above the space 12.
Although the example in which the space is provided is shown, the positions of the spaces 11 and 12 are not limited to this, and they do not have to be at the same place on the pipeline. That is, a configuration in which the position where the space 12 is provided is provided on the upstream side relative to the position where the space 11 is provided, and the reverse configuration are also within the scope of the present invention.

FIG. 9 is a schematic explanatory view showing another structural example of the liquid processing apparatus according to the present invention. In the configuration shown in FIG. 9, two submerged weirs are provided alternately from the ceiling portion of the horizontally arranged conduit 13 and two weirs are provided from the bottom portion. As a result, gas and solids are removed from the liquid to be treated as the liquid to be treated flows while passing between the weir and the submerged weir.

In the above configuration example, the case where the flow direction of the liquid to be treated 23 is from the upper side to the lower side of the reforming tank 3 is shown.
This does not limit the flow direction of the liquid to be treated 23 in the present invention.
It may be configured to flow 23.

Further, the present invention is characterized in that gas or solid is removed from the liquid to be treated (liquid) before the reforming treatment, and the electrode shape of the electrode pair in the reforming tank is not particularly limited. Any shape such as a flat plate electrode, a ring-shaped electrode, a cylindrical electrode, a tape-shaped electrode, a rod-shaped electrode, or a linear electrode may be used. Moreover, the cross-sectional shape of the electrode is not particularly limited, and may be circular or rectangular.

In the present invention, the pulsed electric power supplied from the high-voltage power supply is not limited to a square wave, but may be a rectangular wave, a sine wave, a triangular wave, or the like.

[0030]

When the above-mentioned structure is adopted, gas or solid is not mixed in the discharge region, and therefore when pulsed power is supplied to the electrode pair to reform the liquid existing between the electrodes. Thus, it has been possible to provide a liquid treatment method capable of supplying a stable discharge state across the entire electrodes and an apparatus capable of realizing this method.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view showing a configuration example of a liquid reforming apparatus previously proposed by the present inventors.

FIG. 2 is a schematic explanatory view showing another configuration example of the liquid reforming apparatus previously proposed by the present inventors.

FIG. 3 is a schematic explanatory diagram showing an example of occurrence of discharge between electrodes.

FIG. 4 is a schematic explanatory diagram showing another configuration example of the liquid processing apparatus according to the present invention.

FIG. 5 is a schematic explanatory diagram showing still another configuration example of the liquid processing apparatus according to the present invention.

FIG. 6 is a schematic explanatory diagram showing another configuration example of the liquid processing apparatus according to the present invention.

FIG. 7 is a schematic explanatory diagram showing another configuration example of the liquid processing apparatus according to the present invention.

FIG. 8 is a schematic explanatory diagram showing another configuration example of the liquid processing apparatus according to the present invention.

FIG. 9 is a schematic explanatory diagram showing another configuration example of the liquid processing apparatus according to the present invention.

[Explanation of symbols]

1 Means for removing gas and solids from the liquid to be treated 3 reforming tank 4 power supply 5 Rod electrodes 6 Flat plate electrode 8 pipes (U-shaped pipe) 9 pipes (U-shaped pipe) 11 space 12 spaces 13 pipelines 18 reformer 23 Liquid to be treated 24 discharge 25 Rod electrode 26 ring electrode 27 High voltage pulse power supply

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 1/20 C02F 1/20 A (72) Inventor Masahiko Miura 1-5-5 Takatsukadai, Nishi-ku, Kobe City F-Term in Kobe Research Institute of Kobe Steel, Ltd. (reference) 4D011 AA05 AB07 AC05 AD03 4D037 AA02 AA11 AA13 AA15 AB18 BA23 CA04 CA06 4D061 DA08 DB19 DC09 EA15 EB01 EB07 EB19 EB20 EB33 EB39 FA03 FA20 GC14

Claims (3)

[Claims] 1. A liquid for reforming a liquid sequentially supplied between electrodes by providing at least one pair of electrodes and applying a high voltage pulse to the electrode pairs to form a discharge state between the electrodes. In the treatment method, a gas and / or solid is removed from the liquid upstream of the discharge state forming region. 2. At least one pair of electrodes is provided, and a high voltage pulse is applied to the pair of electrodes to form a discharge state between the electrodes, thereby reforming the liquid sequentially supplied between the electrodes. The liquid processing apparatus configured as described above, further comprising a means for removing gas and / or solid from the liquid upstream of the discharge state forming region. 3. The liquid processing apparatus according to claim 2, further comprising means for extracting gas and / or solid from the means for removing gas and / or solid.