JP2767771B2 - Wastewater treatment equipment by electrolytic oxidation - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for treating wastewater by electrolytic oxidation.

[0002]

2. Description of the Related Art Wastewater treatment methods are roughly classified in principle as follows. 1. 1. Physical treatment method Chemical treatment method 3. Biochemical treatment methodPhysical treatment method is a method of diluting wastewater, discharging it by diluting, sedimenting, filtering, etc., and discharging the wastewater. Some operations may be added. This is the simplest and least costly method. Chemical treatment methods include neutralization, oxidation, reduction,
This method utilizes agglutination, adsorption, and ion exchange reactions.When discharging acid or alkaline waste liquids, the pH is set to a safe pH range, and troublesome molecules are converted into harmless salt precipitates, and captured by ion-exchange resins. How to Treatment facilities also have various methods for adapting wastewater.

[0003] The biochemical treatment method is a method which is suitable for treating organic industrial waste liquid and sewage, and is widely practiced on a large scale. Providing a suitable environment for microorganisms present in the water, the microorganisms propagate using the organic components as nutrients and transform the organic pollutants in the wastewater into harmless substances. There are two types of this method, an oxidation reaction by an aerobic microorganism and a reduction (rot) effect by an anaerobic microorganism.

In general, since it is difficult to remove organic components in one step, there are many problems such as a need to combine the above various methods, an increase in processing time, and an increase in place and area.

Since wastewater, especially plating wastewater, particularly electroless plating wastewater, contains metal ions, biochemical treatment using activated sludge cannot be employed. Further, physical wastewater treatment methods such as precipitation and filtration cannot remove metal ions.

The main methods of treating plating wastewater are as follows. a. Recovery method This method recovers and reuses chromic acid in chromium plating waste solution and chromate waste solution by using ion exchange. Also,
There is also a method in which the waste liquid is heated and concentrated for reuse. The feature is that sludge cannot be formed, and part of wastewater treatment costs can be covered by reuse. b. Decomposition method This is a method for decomposing cyan waste liquid by adding sodium hypochlorite to cyan waste water to decompose cyan into nitrogen and carbon dioxide and render it harmless. c. Precipitation method It is a method of reducing hexavalent chromium in chromium plating wastewater to trivalent and adding alkali to precipitate as chromium hydroxide, or adding alkali to copper sulfate plating wastewater to precipitate copper, but discarding sludge We are in trouble with place. d. Neutralization method This is a method in which an acid or alkali is added to an alkali degreasing solution or sulfuric acid derusting solution to make it neutral. However, it is difficult to remove and recover the metal complex salt by any of the methods.

As one of the chemical wastewater treatment methods, electrolytic oxidation can be considered, but the plating wastewater has a COD of several thousands to 20,000.
Even if it is electrolytically oxidized, the COD can be reduced only to about 3000 at most, and since this concentration is higher than the regulation value, the water cannot be discharged to the sewage. Therefore, stirring may be considered to increase the efficiency of electrolytic oxidation, but a sufficient stirring effect cannot be achieved with propeller stirring. Aeration can be considered as another stirring means, but if aeration is performed to achieve a sufficient stirring effect, hydrogen generated by electrolysis,
There is a high possibility that oxygen in the air supplied more and more by aeration mixes to form explosive gas. Therefore, as for the treatment of plating wastewater, electrolytic oxidation was used only for a part of cyanide wastewater.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to treat wastewater, especially metal-containing wastewater, especially electroless plating wastewater, by electrolytic oxidation to greatly reduce BOD and COD below regulated values, It is an object of the present invention to provide a wastewater treatment apparatus for effectively removing a metal component.

[0009]

The present invention is characterized by comprising (A) an electrolytic oxidation tank provided with at least one pair of electrodes, and (B) a vibrating stirrer for vibrating and stirring the inside of the tank. The present invention relates to a wastewater treatment apparatus using electrolytic oxidation.

Preferred conditions for the electrolytic oxidation of the present invention are: electric quantity *; 1 to 10 amps / liter; current density; 3 to 15 A / dm ² bath temperature; 20 to 80 ° C. distance between electrodes; 5 to 10 cm pH; 5 to 6.0. * Current flowing per liter of processing solution

In the present invention, when the wastewater is irradiated with ultraviolet rays, COD and BOD in the wastewater can be further reduced.

As the irradiation lamp for irradiating the ultraviolet rays, a hydrogen discharge tube: a continuous spectrum of 1680 to 5000 °, a xenon discharge tube: a continuous spectrum of 2400 to 12000 ° and a far-infrared spectrum Mercury lamp: an emission line spectrum of mercury (2000 to 3000 °) Ultra-high pressure mercury lamp: Continuous spectrum of 2000-3000Å Sterilizing lamp: Bright line spectrum of mercury (2000-3000Å) Fluorescent health light: About 2900Å and emission spectrum of mercury (2000-3000Å) Black light lamp: Fluorescent ray of about 3600Å and mercury Emission line spectrum High-pressure C ultraviolet lamp: high output, wide band, and extremely high UV energy efficiency. The wavelength is 200-40
0 nm, preferably 200-300 nm,
Generally, a high-pressure mercury lamp whose center has a wavelength of 253.7 nm can be used.

As the ultraviolet lamp, one or more commercially available ultraviolet lamps of 10 W to 40 KW are used. As a usage form, in addition to a method in which a part of the pipeline for circulation from the electrolytic oxidation tank is made into a transparent pipe and an ultraviolet irradiation lamp is installed therein, a double pipe and a lamp can be provided at the center thereof.

Examples of the wastewater in the present invention include metal-containing wastewater such as plating wastewater, electroless plating wastewater, and wastewater of a cleaning solution used for plating pretreatment. In particular, the apparatus of the present invention is extremely effective for wastewater containing a metal complex salt, for example, concentrated electroless plating wastewater.

Even if these wastewaters are treated by the conventional electrolytic oxidation, the COD is at most about 3000, and a conventional stirring such as a propeller type stirring, a circulating stirring or a milling stirrer using a diffuser tube is used in combination. However, the COD level could not be reduced to 1000 or less.

On the other hand, when the vibration agitation developed by the present inventor is used in combination with the electrolytic oxidation, the level of COD can be surprisingly reduced to a level of two digits or less. That is, (a)
The present invention has the effects of improving the stirring effect, (b) suppressing the generation of mist, (c) allowing a high current to flow, and (d) preventing overcurrent even if the distance between the electrodes is shortened. The industrial contribution is extremely large.

The electroless plating solution comprises: (A) a main component 1. Metal salts (including nickel, cobalt, copper, tin, silver, platinum and alloys thereof) Reducing agents: sodium hypophosphite, boron hydride, sodium, hydrazine, etc. (B) Auxiliary components 1. pH adjusters: basic compounds such as sodium hydroxide and ammonium hydroxide, inorganic acids, organic acids, etc. 2. Buffers: inorganic acids such as oxycarboxylic acid boric acids such as sodium citrate and sodium acetate, which have a low dissociation constant; organic acids, alkali salts of inorganic acids, etc. Complexing agents: alkali salts of organic acids, triethanolamine, ethyleneamine, glycine, etc. Accelerator: sulfide, fluoride 5. 5. Stabilizer: Lead chloride, sulfide, nitride, etc. Improving agent: Contains a surfactant, etc., and ages due to a difference in balance with the progress of plating. As a chemical treatment method of the electroless nickel aging solution, there is a method of performing an oxidation treatment using hydrogen peroxide, but the oxidizing ability of a complexing agent and a buffer is weak. The electrolytic oxidation of the present invention can generate oxygen in an aging plating bath with a small electric power. Further, nickel is deposited on the cathode, and the reducing agent, complexing agent and buffering agent can be oxidized and decomposed at the anode. The effect is further improved by adding chlorine ions to promote oxidative decomposition.

The vibration stirrer according to the present invention is disclosed in Japanese Patent Publication No. Hei 6-71544 developed by the present inventor,
-287799, JP-A-6-304461, and Japanese Patent Application Nos. 5-245950, 6
Although any of the inventions of US Pat. No. 3,337,183 can be used, the vibration stirrer of the present invention basically includes a vibration generating unit having a vibration motor, a vibration shaft connected thereto, and a one-stage non-rotatably fixed to the vibration shaft. Alternatively, the vibrating blade portion is composed of multi-stage vibrating blade portions, and the vibrating blade portion bends near its tip due to vibration, whereby the system vibrates and flows to be stirred.

Further, in the present invention, the vibration generating section and the electrolytic oxidizing tank are provided with three or more, preferably four, support rods extending vertically downward from the vibration generating section in FIG. It is preferable to engage with a support rod extending vertically upward from the oxidation tank side and a spring surrounding the upper and lower support rods. In particular, it is preferable that the upper and lower support rods are kept in a non-contact state by the spring. As a result, even if the vibration generating portion generates a lateral shake, the above-mentioned engaging portion can absorb the lateral shake well, and it is possible to prevent the occurrence of undesirable lateral shake and the generation of noise accompanying the entire device. it can.

The vibrating stirrer provided with this anti-lateral sway mechanism is shown in FIGS. 3, 4 and 5, and an enlarged view of the anti-lateral sway mechanism in these figures is shown in FIG. In the drawing, 5 is a spring, 46 is an electrolytic oxidation tank or a gantry or reinforcing member provided thereon, 47 is a support rod extending vertically below the basic vibration member or vibration transmitting member, and 48 is vertically extending above the 46. Support rod.

The degree of vibration is usually sufficient at about 10 to 60 Hz.
Can be raised to the second place. If the vibration frequency is high, cracks or breaks may occur due to the concentration of vibration stress in the vicinity of the contact between the vibration generating portion and the vibrating rod. Therefore, vibration stress dispersing means (Japanese Patent Application No. No. 3,337,183, all of which techniques can be used in the present invention.

One vibration stress dispersing means is a rubber ring provided around the vibrating bar below the vibrating portion at the connecting portion between the vibrating portion and the vibrating bar, the length of which is greater than the diameter of the vibrating bar. Preferably, it is long, usually 3 to 8 times the diameter of the vibrating bar, and its thickness is 1.3 to 3.0 times, especially about 1.5 to 2.5 times larger than the diameter of the vibrating bar. From another viewpoint, when the diameter of the vibrating bar is a round bar having a diameter of 10 to 16 mm, the thickness of the rubber ring is preferably 10 to 15 mm, and when the diameter of the vibrating bar (round bar) is 20 to 25 mm. The thickness of the rubber ring is preferably 20 to 30 mm. For example, as shown in FIG. 7, when connecting the vibration rod 8 to the vibration transmission member 3, the vibration rod 8 is passed through a predetermined hole of the vibration transmission member 3, and the ends of the vibration rod 8 are nuts 12, 13, On the other side of the vibration transmitting member 3, the rubber ring 18 is inserted into the vibrating rod 8 and fixed on the opposite side of the vibration transmitting member 3 by the nuts 14 and 15.

The rubbery ring is made of a hard natural rubber, a hard synthetic rubber, a synthetic resin or the like having a Shore A hardness of 80 to 120;
Preferably, it can be composed of 90 to 100 hard elastic bodies. In particular, hard urethane rubber having a Shore A hardness of 90 to 100 is preferable in terms of durability and chemical resistance.

The vibration is performed by a vibration motor or the like which generates a vibration of 10 to 500 Hertz (Hz), preferably 20 to 400 Hertz (Hz), particularly preferably 20 to 300 Hertz (Hz). The relationship between the output of the vibration motor and the stirring capacity is approximately as follows in the case of a normal aqueous solution.

[Table 1] Output of vibration motor Stirring capacity 75W (200V, 3 phase) -200 liters 150W (200V, 3 phase) 200-350 liter 250W (200V, 3 phase) 350-800 liter 400W (200V, 3 phase) 800リ ッ ト ル 1500 liters 750 W (200 V, 3 phase) 1500 な お 2500 liters If the motor output is set to 3 KW, a 100 m ³ capacity can be sufficiently stirred.

Usually, the vibration motor is set on a gantry placed on the electrolytic oxidation tank, on the side wall of the electrolytic oxidation tank or on a hard floor. When the tank is thin (stainless steel tank 5 mm or less) and vibration is transmitted to the tank side wall or floor by the vibration of the liquid, it is preferable to install a gantry outside the tank. When the thickness of the tank is 5 mm or less, a reinforcing member may be attached to the side wall of the tank in such a manner as to fasten a band, and the vibration generating section may be installed there. The vibration generated by the vibration motor is transmitted to the vibrating rod via the basic vibration member. In this case, the vibration motor is usually provided above the basic vibration member (FIG. 4,
It is preferable to set it in such a manner that it is hung below (see FIG. 5) (see FIG. 3). By doing so, the center of gravity can be lowered, and the occurrence of lateral displacement can be reduced.

For example, as shown in FIG. 3, a gantry 6 is provided on the upper side surface of the electrolytic oxidizing tank 7, on which a basic vibration member 2 is provided on a support with a spring 5, and a vibration motor 1 is mounted thereon. The attachment may be above the basic vibration member 2 as shown in FIGS. 4 and 5, but the attachment below it lowers the center of gravity of the vibration generation source and can prevent unnecessary side-to-side movement. In FIG. 3, the vibration motor 1 is suspended from the basic vibration member 2. In this case, the vibration transmission member 3 is unnecessary, and the size can be reduced. Vibration motor 1
Does not necessarily need to be provided on the electrolytic oxidation tank 7, but extends the basic vibration member or the vibration transmission member to the outside of the electrolytic oxidation tank, and attaches a vibration motor to the upper or lower side of the extended basic vibration member, To the vibrating rod.

As shown in FIG. 3, two vibrating rods 8 can be mounted on both sides of the vibrating motor, or only one vibrating rod can be mounted as shown in FIG.

The vibration width of the tip of the vibrating blade portion by the vibrating motor is about 8 to 20 mm, and the frequency of the vibrating motor is determined by how much the Hz is determined by the inverter, but usually it is 2000 to 6000 vtm (frequency / frequency).
Min), preferably 2000 to 4000 vtm.

The non-rotating vibrating blade portion may be composed of a vibrating blade plate and a fixing member for the vibrating blade plate, or a laminate of a plurality of vibrating blade plates, or an integrally molded vibrating blade plate and a fixing member for the vibrating blade plate. Can be used.

As the material of the vibrating blade, preferably, a thin metal, a resilient synthetic resin, rubber or the like can be used as a material, but at least a tip portion of the blade is fluttered by a vertical vibration of the vibrating motor. This is a thickness that exhibits a striking state, that is, a state in which a bend occurs), whereby a flow can be given to the system in addition to the vibration.
Titanium, aluminum,
Copper, iron, stainless steel and their alloys can be used. As the synthetic resin, polycarbonate, vinyl chloride resin, polypropylene and the like can be used. The thickness is not particularly limited in order to increase the effect of vibration by transmitting vibration energy, but generally 0.2 to 2 mm for metal and 0.5 to 10 mm for plastic. If the thickness is excessively large, the effect of the vibration stirring decreases.

When an elastic synthetic resin, rubber or the like is used as the material of the vibrating blade plate, the thickness is not particularly limited, but is generally preferably 1 to 5 mm. In the case of a metal such as stainless steel, it is preferably 0.2 to 1 mm. It is preferably 0.5 mm. The amplitude of the diaphragm is 2 to 30 mm,
Preferably it is 5 to 10 mm.

The vibrating blades can be attached to the vibrating shaft in one or more stages. When the number of vibrating blades is multi-stage, 5 to 7 blades are preferable depending on the size of the vibrating motor.
When the number of stages is increased, if the load of the vibration motor is increased, the vibration width decreases, and the vibration motor may generate heat. The angle of the vibrating blade portion may be horizontal with respect to the vibrating axis, but it is preferable that the inclination angle α (see A in FIG. 8) be inclined at 5 to 30 degrees, particularly 10 to 20 degrees to give directionality to the vibration. Thereby, the flow of the liquid can be further promoted.

The vibrating blade portion can be formed by sandwiching the vibrating blade plate from both upper and lower surfaces with a vibrating blade plate fixing member and fixing it to the vibrating rod. Further, as shown in FIG. 8, it is preferable that the fixed member 10 for vibrating blades and the vibrating blade 9 are integrally inclined and / or curved as viewed from the side surface of the vibration shaft. Even if it is curved, it is preferable to have an inclination of 5 to 30 degrees, especially 10 to 20 degrees, as described above. It is effective to disperse the vibration stress if the vibrating blade plate and the fixing member for the vibrating blade plate have the same inclination and / or curved surface. In particular, when the vibration frequency becomes high, Damage can be avoided.

Further, the vibrating blade plate and the fixing member for the vibrating blade plate can also be manufactured by integrally molding, for example, using plastics (see FIG. 8C). In this case, compared with the case where the vibrating blade plate and the fixing member for the vibrating blade plate are used separately, it is possible to avoid a disadvantage that the object to be processed permeates and adheres to the joint portion, and it takes time to clean. . Further, by integrating the blade plate and the fixing member as shown in FIG. 8, a thickness step does not occur and stress concentration can be avoided, so that damage to the blade plate can be avoided.

When the vibrating blades are inclined and / or curved, the lower ones among a number of vibrating blades.
Two may have a downward slope and / or curvature, and the other may have an upward slope and / or curvature. In this case, the stirring at the bottom of the stirring tank can be sufficiently performed, and the formation of the pool at the lower portion can be prevented.

The degree of the "bending phenomenon" of the vibrating blade plate caused by the vibration of the vibrating blade portion depends on the frequency at which the vibration is applied,
The length and thickness vary depending on the length and thickness of the vibrating blade, the viscosity of the material to be agitated, the specific gravity, and the like. When the frequency and the thickness of the vibrating blade are kept constant and the length of the vibrating blade is changed, the degree of bending of the vibrating blade becomes the length as shown in FIG. As the length increases, it increases up to a certain stage, but if it is too large, the bending becomes small, and some length hardly bends, and if the vibrating blade is made longer, the bending becomes larger again Has been found to be repeated. FIG. 9 shows a model of this state.

Therefore, it is preferable that the length of the vibrating blade (the length of the portion before the fixing member) is selected to be the length indicating the first peak or the length indicating the second peak. Is preferred. Whether the length has the length indicating the first peak or the length indicating the second peak can be appropriately selected depending on whether the vibration of the system is increased or the flow is increased. When the length indicating the third peak is selected, the vibration width becomes small.

SUS at frequency 37-60Hz, 75KW
When the length of the first peak and the length of the second peak were obtained for various thicknesses of the diaphragm made of 304, the following results were obtained.

[0039]

[Table 2] The length in this experiment is the length from the tip of the fixing member for the vibrating blade to the tip of the vibrating blade (the length of m in FIG. 8A). The length to the tip of the fixing member (the length of n in FIG. 8A) is 27 mm, and the tilt angle α of the vibrating blade is 15 ° upward.

In the present invention, in addition to vibration stirring, aeration can be used if necessary, and a diffuser can be installed at the bottom of the tank. However, since hydrogen is generated in the system, the explosion It is necessary to pay attention not to form the motor, and it is preferable that the motor is also an explosion-proof type.

It is preferable that the cathode used in the present invention be one from which the recovered metal can be easily electrodeposited and the electrodeposited metal can be easily peeled off later. Further, as the anode, a material through which a current easily flows and which is insoluble and does not wear out is preferable, and a lead oxide-coated electrode is particularly preferable. In a preferred electrode used in the embodiment of the present invention, the cathode is a stainless steel electrode (eg, S
US304), and the anode used was a perforated plate in which an α-type lead dioxide layer was coated on a titanium substrate and then a β-type lead dioxide layer, and the total lead oxide layer was 0.5 to 1 mm. The current density could be increased by using these electrodes.

[0042]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited by this.

Example 1 A 200 liter heat-resistant vinyl chloride resin tank was charged with 30 g / liter of nickel sulfate (5200 ppm of nickel).
), Containing 180 g of electroless nickel plating wastewater containing 30 g / l of sodium hypophosphite and 20 g / l of glycine and having a pH of 4.2, the above-mentioned lead peroxide-titanium electrode as an anode, and the cathode as Stainless steel (SUS30
4) Using a plate, arranging three pairs of electrodes as shown in FIG. 1, passing a current through a rectifier, and increasing the current density to 5.2 A /
dm ² . The effective electrode area of the electrode was 96 dm ² , and the distance between the electrodes was 50 mm.

The conditions of the electrolytic oxidation were as follows: the amount of electricity was 2.5 amps / liter, the voltage was 12 volts, and the temperature of the electrolytic oxidizing bath of 200 liters was an electric heater, which was used to raise the initial temperature of the electrolytic oxidizing bath. Was kept at approximately 60 ° C.

The vibration stirrer 22 was arranged as shown in FIG. The flow caused by the vibration agitation causes the electrode groups 21, 21,...
The vibrating stirrer 22 was installed on the side of the electrode plate in the direction of extension so as not to be disturbed by the presence of. The vibration stirrer 22 is
As shown in FIG. 3, two vibrating shafts 8 and 8 made of stainless steel and a vibrating blade plate 9 fixed to the vibrating blade plate 9 via a vibrating blade fixing member are used as a vibrating motor of 75 W × 200 V. 1 is received via the basic vibration member 2 and the vibration bar 8, and the electrolytic oxidation bath is vibrated and stirred. In the bath, a flow is generated by the vibration of the vibrating blade fixing member and the bending of the vibrating blade plate 9, and the bath is uniformly stirred. The vibration motor is controlled at 42 Hz by an inverter, and the electrode current is 15 Hz.
V, 1000 amp rectifier allows 96 dm ² , 1
It was operated at a constant current and voltage of 5 V, 500 amps.

After about 4 hours, the nickel oxide test showed that the electrolytic oxidation bath had a nickel content of several ppm.
After the passage of time, the solution was colorless and transparent, and the result of the nickel pack test indicated that nickel was 0 ppm. The COD value was 200 hours after 4 hours.
0 ppm, 450 ppm after 8 hours, and 12 ppm
After time, the COD had dropped to 45 ppm. Table 3 shows the results.

[0047]

[Table 3]

Embodiment 2 As shown in FIG. 2, a circulation circuit 24 for taking out a liquid from a part of the apparatus shown in FIG. 1 and returning the liquid to the apparatus again is formed. The tube is a transparent tube made of quartz glass, in which a broadband C ultraviolet lamp 23 (2
KW) One lamp was inserted and ultraviolet irradiation was performed. The circulation rate of the liquid was 1.5 liters per minute (can be increased up to 10 liters). As a result, after 4 hours, the nickel pack test resulted in 2 ppm of nickel, and C
The OD was reduced to 20 ppm, and the combined effect of the vibration stirring and the ultraviolet light was remarkable.

COMPARATIVE EXAMPLE 1 In Example 1, when the vibration stirring was not carried out (this corresponds to a normal electrolytic oxidation treatment), the nickel content after 4 hours was measured by a nickel pack test with a scale over. It was unacceptably large and was estimated to be of the order of three orders of magnitude in ppm. COD is also 7000-800
It was 0 ppm.

Example 3 Examples 1 and 2 were repeated except that the bath composition in Examples 1 and 2 was a nickel plating waste solution, the SUS304 electrode was used for the anode, and the nickel-plated copper plate was used for the cathode. Nickel plating waste liquid is nickel sulfate 5g /
1 liter, 25 g / liter of sodium hypophosphite, 25 g / liter of sodium sulfite, and 25 g / liter of succinic acid. The results showed the same excellent nickel content reduction and COD reduction effects as in Examples 1 and 2.

Example 4 Fehling's solution A: Copper sulfate 34.6 g / 50 ml Fehling's solution B: potassium sodium tartrate 173 g / 500 ml Sodium hydroxide 50 g / 500 ml A system comprising the same amount of A and B was mixed. Formaldehyde was mixed at a ratio of 1/10 to 1/5 by volume, and a solution corresponding to an electroless copper electrolytic waste solution obtained by adjusting pH 12 to pH 4.5 was obtained.
The treatment was performed in the same manner as in Example 1 for 8 hours. Electrolysis at 50 ° C
And kept at 70 ° C. Copper pack test results,
Copper was 0 ppm and COD was 150 ppm.

Example 5 When Example 4 was used in combination with ultraviolet irradiation in the same manner as in Example 2, the copper pack test showed 0 ppm copper and COD
Was 20 ppm. Copper is 98% as metal
It could be recovered.

Comparative Example 2 In Example 4, when the vibrating stirrer was not operated, 8
The results of the copper pack test after the lapse of time showed that the copper content was too large to be measured due to scale over.

Example 6 Composition Nos. The waste liquid of the alkaline degreasing agent of No. 1 was subjected to electrolytic oxidation treatment in the same manner as in Example 1.

[0055]

[Table 4]

The results are as shown in the following table.

[Table 5] No. 2-No. No. 5 is also No. 5 Approximately the same results were obtained as those of Example 1.

Example 7 The waste liquid of the alkaline degreasing agent was used together with ultraviolet irradiation in the same manner as in Example 2. The results are shown in the table below.

[Table 6] No. 2-No. No. 5 is also No. 5 Approximately the same results were obtained as those of Example 1.

[0058]

【effect】

1. The metal component was recovered in high yield as a metal carrier. 2. COD and BOD could be efficiently reduced in a shorter time than in the conventional method, and the levels of COD and BOD could be surprisingly reduced. 3. Even in the case where a metal is contained as a complex salt in the waste liquid, the metal content can be reduced to one digit or less in ppm, and the metal component in the waste liquid can be recovered as a simple metal. . 4. Since there is no need for aeration, there is almost no intense off-flavor associated with aeration.
Does not cause odor-based pollution. 5. Mist generation is smaller than in conventional electrolytic oxidation. 6. The treatment liquid was able to reduce metal components, BOD, and COD to such an extent that wastewater could be discharged into sewage. 7. The device of the present invention is simple in equipment and small in use area.

[Brief description of the drawings]

FIG. 1 is a top view of a wastewater treatment apparatus according to the present invention used in Example 1. FIG.

FIG. 2 is a top view showing one embodiment in the case where ultraviolet irradiation is used in combination in the present invention.

FIG. 3 is a cross-sectional view showing one specific example of a vibration stirrer used in the present invention.

FIG. 4 is a cross-sectional view showing one specific example of a vibration stirrer that can be used in the present invention.

FIG. 5 is a cross-sectional view showing another specific example of the vibration stirrer usable in the present invention.

FIG. 6 shows one of the vibration absorbing mechanisms (lateral sway prevention mechanisms) of the present invention.
It is an expanded sectional view showing an example.

FIG. 7 is an enlarged sectional view when a rubber ring is used as a vibration stress dispersing means in the vibration stirrer used in the present invention.

8A and 8B show a vibrating stirrer composed of a vibrating blade plate and a vibrating blade fixing member, wherein A is a cross-sectional view, B is a plan view, and C is formed by integrally integrating A and B. FIG. It is sectional drawing in the case.

FIG. 9 is a graph schematically showing the relationship between the length of a vibrating blade and the degree of bending.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Vibration motor 2 Basic vibration member 3 Vibration transmission member 4 Connection part 5 Spring 6 Stand 7 Electrolytic oxidation tank 8 Vibration bar 9 Vibrating blade plate 10 Vibrating blade plate fixing member 12 Nut 13 Nut 14 Nut 15 Nut 16 Washer ring 17 Screw groove 18 Rubber ring 21 Electrode 22 Vibration stirrer 23 Ultraviolet lamp 24 Circulation circuit 26 Pump 30 Spacer 46 Electrolytic oxidation tank or pedestal or reinforcing member provided thereon 47 Basic vibration member or pedestal or auxiliary member provided thereon 48 A support rod vertically extending above 46 A support rod vertically extending above 46 above

Claims (7)

(57) [Claims] 1. A wastewater treatment apparatus by electrolytic oxidation, comprising: (A) an electrolytic oxidation tank provided with at least one pair of electrodes; and (B) a vibrating stirrer for vibrating and stirring the inside of the tank. 2. The vibration stirrer comprises a vibration generator having a vibration motor, a vibration shaft connected thereto, and a single-stage or multi-stage vibration blade fixed non-rotatably to the vibration shaft. 2. The wastewater treatment apparatus according to claim 1, wherein the vicinity of the tip is formed by vibration. 3. The vibration generating section is supported by three or more support rods extending vertically downward, correspondingly, the support rods extending vertically upward from the electrolytic oxidation tank side and springs surrounding the upper and lower support rods. The wastewater treatment apparatus according to claim 2, wherein the wastewater treatment apparatus employs electrolytic oxidation. 4. The wastewater treatment apparatus according to claim 2, wherein the vibration motor can generate an arbitrary vibration between 10 and 500 Hz by an inverter. 5. The vibrating blade portion is set at 0 ° in a direction perpendicular to the vibrating rod.
゜, 5 in any direction from (+) to (-)
5. The wastewater treatment apparatus according to claim 2, wherein the inclined wastewater treatment apparatus is inclined by 30 degrees. 6. A vibration stress dispersing means is provided at a connecting portion between said vibration generating portion and said vibrating rod.
A wastewater treatment apparatus according to claim 4 or 5, wherein the wastewater treatment apparatus uses electrolytic oxidation. 7. The wastewater treatment apparatus according to claim 1, further comprising means for irradiating the wastewater with ultraviolet rays.