JPH02222771A - Sewage purification equipment using electrolytic treatment method - Google Patents

Abstract

PURPOSE:To improve the efficiency in treatment by inclining both electrode plates to incline the passage between the electrode plates, passing an inlet passage for water to be treated through the lower end of the passage and providing a floc floating and accumulating part above both electrode plates. CONSTITUTION:A DC voltage is impressed on the electrode plates of first and second electrolysis parts 4 and 5. Electrode reactions such as the dissolution in the water to be treated and the oxidation, reduction, decomposition and deposition of suspended matter are carried out in the passage 8 between cathodes and anodes in the first electrolysis part 4. When a DC voltage is an impressed between the electrode plates 6 and 7, fine hydrogen gas bubbles are generated from the cathode plate 7, and aluminum ion is eluted from the anode plate 6. The hydrogen gas bubbles ascend vertically in the passage 8, collide with the surface of the anode plate 6, then descend and again ascend. Consequently, a gushing stream is generated in the passage 8, and the device can be used for a long time.

Description

[Detailed description of the invention] (Industrial application field) The present invention is applicable to turbid water existing in lakes, marshes, ponds, rivers, canals, sea areas, etc., and various sewage such as domestic wastewater such as kitchens and sewage. The present invention relates to a sewage purification device that purifies sewage by removing dissolved and suspended substances through electrolytic treatment.

(Prior Art) Conventionally, a mold treatment method has been used as a method for purifying sewage such as domestic wastewater and industrial wastewater. This utilizes the fact that dissolved and suspended substances are oxidized, reduced, decomposed, precipitated, adsorbed, coagulated, floated, and separated by electrolytically treating wastewater by passing it between negative and positive electrodes. Conventional equipment using this electrolytic treatment method has negative and positive electrode plates facing each other in the electrolytic treatment chamber, and the sewage to be treated is forcibly fed into the electrolytic cell by a pump. Generally, the electrolytic treatment was carried out by forced flow through the electrolytic treatment tank, and the flocs generated during this time were floated and separated.

Further, in the conventional apparatus of this kind, the picture electrode plates are each oriented in a vertical direction, and the wastewater to be treated is configured to rise or fall vertically within the electrolytic treatment tank.

(Problems to be Solved by the Invention) In the conventional apparatus as described above, the water to be treated is forced to flow between vertically oriented negative and anode plates arranged in parallel using means such as a pump. Because of this, the wastewater to be treated flowing near the anode plate is strongly oxidized and strongly coagulated by the anode metal ions. In addition, the wastewater to be treated flowing near the cathode plate is strongly reduced and
#Hydrogen gas bubbles generated from the R electrode float to the surface without contributing much to the mixing and stirring of the liquid, and the entire solution is not uniformly treated and flows through, resulting in a low electrolytic treatment efficiency. was there.

Furthermore, in the electrolytic treatment, when an oxide film is formed on the anode plate due to the anodic oxidation effect, the amount of anode metal ions generated decreases, and the aggregation effect of these metal ions is reduced. For this reason, in conventional devices of this type, when using the action of anode metal ions, it is necessary to frequently remove the oxide film on the anode plate, and the anode plate must be replaced each time. there were.

SUMMARY OF THE INVENTION In view of the above-mentioned conventional problems, the present invention aims to provide a sewage purification device in which the entire wastewater to be treated flowing through the wastewater can be electrolytically treated uniformly and efficiently with less energy and energy.

(Means for Achieving the Object) A feature of the present invention for solving the above-mentioned conventional problems and achieving the intended purpose is that a large number of active anode plates and cathode plates are arranged facing each other. , in a sewage purification device in which the space between the electrode plates is used as a sewage flow path to be treated, the sewage to be treated is caused to flow through the flow path, and electrolytically treated during the flow, the bipolar plates are tilted. The flow path between the two electrode plates is inclined, and the anode plate is placed on the upper side and the cathode plate is placed on the bottom side so that they face each other, and the lower end of the flow path between the two electrode plates is communicated with the water introduction path, A floc floating accumulation section is provided above the electrode plates, and the wastewater to be treated is caused to flow by an upwelling flow caused by electrolytic treatment between the electrode plates.

(Function) In this sewage purification device, when a DC voltage of, for example, about 6 V is applied between the two electrode plates, dissolution and
The suspended solids undergo electrode reactions such as oxidation, reduction, decomposition, and precipitation, and anode metal ions are eluted from the upper anode plate, and fine hydrogen gas bubbles are generated from the lower cathode plate. Dissolved and suspended substances are aggregated by the action of metal ions, which are products of this anode reaction. On the other hand, hydrogen gas, which is a cathode reaction product, is generated on the surface of the lower cathode plate, rises vertically in the channel between the two inclined electrodes, collides with the surface of the anode plate, and descends. It moves up again in a vortex motion. During this movement, gas bubbles adhere to the substances aggregated by the anodic reaction products, forming a flow bubble, which gradually grows and rises during the vortex movement. Furthermore, when many gas bubbles enter the solution, the specific gravity of the gas-liquid mixture in the flow path, that is, the supporting water head, decreases.
New wastewater to be treated flows in from the wastewater introduction channel.

Due to these two phenomena, an upwelling flow accompanied by a vortex phenomenon of gas-liquid mixing is generated in the flow path, and only by applying voltage to the bipolar plates, a flow of water is generated in accordance with the amount of gas bubbles generated.

In addition, this vortex phenomenon increases the stirring efficiency of indoor liquid.

Promotes electrode reactions such as oxidation, reduction, decomposition, and precipitation in which electrons are directly exchanged at the interface between the electrode and the wastewater to be treated, and electrode reaction products such as adsorption, aggregation, and flotation react with components in the wastewater to be treated. Promote secondary reactions.

In addition, as the electrode reaction and secondary reaction progress, the floc attaches gas bubbles and escapes from the vortex motion region, floats to the surface of the anode plate, and then rises along this surface while condensing to the water surface. surface. Hydrogen gas has a large reducing power and suppresses oxidation of the anode surface. In addition, as the flocs float along the anode surface, the anode surface is polished and no oxide film adheres to it. An example of this will be explained with reference to the drawings.

In the figure, 1 is the water surface of a sewage tank to be treated, such as an aquarium, pond, lake, marsh, etc., and 2 is a water surface floating on the water surface 1.
This is an electrolytic treatment tank. Inside the electrolytic treatment tank 2, first and second electrolytic treatment sections 4.5 are provided with a partition plate 3 in between.

As shown in FIGS. 3 and 4, the electrolytic treatment section 4 has a large number of active anode plates 6 made of aluminum and cathode plates 7 made of the same material facing each other, with a gap between the two plates 6 and 7. To be treated/water flow paths 8, 8...

As shown in FIGS. 2 and 3, the bipolar plates 6 and 7 have an anode plate 6 on one side of an insulating substrate 9 and a cathode plate 7 on the other side.
The electrode plates 10 are stacked and fixed to form -t electrode plates 10, and the electrode plates 10 are tilted at an angle of about 60' and arranged in parallel at intervals of about 3C11 to partition the inside of the electrolytic treatment tank 2 into a large number. ,
A water passage to be treated 8.8 is closed between the electrode plates 10.

At the bottom of the first electrolytic treatment section 4, there is a bottom plate 11 with the lower end of each electrode plate 10 in contact with the upper surface, and the space between this bottom plate 11 and the bottom plate 2b of the electrolytic treatment tank 2 is a water introduction path 12 for water to be treated. It has become. In the bottom plate 11, slit-shaped water holes 13, 13, .

The second electrolytic treatment section 5 is continuous with the first electrolytic treatment section 4 through the upper part of the electrolytic treatment tank 2, and inside it, an inert anode plate 14 consisting of a large number of graphite plates arranged upright and an aluminum The cathode plates 15 consisting of the above are arranged to face each other. This bipolar plate 1415 is made by stacking and fixing the anode plate 14 on one side of the insulating substrate 16 and the cathode plate 15 on the other side to form - electrode plates 17 in the same manner as the above-mentioned electrode plates. These are arranged vertically at intervals to partition the electrolytic treatment tank 2, and form a large number of channels 18, 1 which are open to the top and bottom.
It consists of 8... This flow path 18.18・
The lower end of ... is the discharge flow 1/? from the bottom of the electrolytic treatment tank 2?
It is connected to +19.

The upper opening portion of the electrolytic treatment tank 2 serves as a floc flotation and accumulation section 20 common to the first and second electrolytic treatment sections 4 and 5.

A scum collection pit 21 is provided outside one side of the upper part of the electrolytic treatment tank 2 . An overflow weir 22 is provided between the scum recovery pit 21 and the floc floating accumulation section 20, which is lower than the upper edge of the other portions of the electrolytic treatment tank 2.

Next, a sewage purification process using the apparatus configured as described above will be explained.

When using this device, the electrolytic treatment tank 2 is floated above the water surface 1 so that the height of the upper edge of the overflow weir 22 is slightly higher than the water surface 1. The height of this overflow weir 22 from the water surface 1 is such that even if the water level in the electrolytic treatment tank 2 rises due to the upwelling flow generated by the electrolytic treatment described later, the treated water inside will not overflow. , and the height is such that the floated and separated flocs overflow on the water surface. On the other hand, the tip opening 12a of the water introduction path 12 to be treated is opened below the water surface 1 at the water point, and the tip opening 19a of the discharge channel 19 is opened below the water surface 1 at the drain point.

In this state, a DC voltage is applied to each electrode plate of the first and second electrolytic treatment sections 4.5. As a result, the flow between each negative and positive electrode of the first electrolytic treatment section 4! ? In 88, dissolved and suspended substances in the water to be treated undergo electrode reactions such as oxidation, reduction, decomposition, and precipitation. On the other hand, since aluminum plates are used for both electrode plates 6.7, when a DC voltage of, for example, 6V is applied between the picture electrode plates 6.7, minute hydrogen gas bubbles are generated from the cathode plate 7, and the anode plate 6. Aluminum ions are eluted from. The suspended solids are aggregated by the action of aluminum ions, which are the @ electrode reaction products, and hydrogen gas, which is the electrode reaction product, is further attached to the aggregates. As a result, the suspended matter appears to float as flocs with extremely low specific gravity.

Further, as shown in FIG. 3, the hydrogen gas bubbles rise vertically in the inclined channel 8, collide with the surface of the anode plate 6, descend, and rise again. Furthermore, when many gas bubbles are dissolved, the specific gravity of the gas-liquid mixture in the stream 8@8, that is, the supporting water head becomes smaller, and new wastewater to be treated flows in from the water outlet of the bottom plate 11. Due to these two phenomena, flow #
18, an upwelling flow accompanied by a vortex phenomenon of gas-liquid mixing occurs. The specific gravity ρ of the gas-liquid mixture is p□0.98 (when the current density is 50 amperes/m'/hr, for example)
lrf/cm'. The upwelling flow rate depends on current density, depth of the electrolytic tank, etc., but can ultimately be controlled by adjusting the difference between the water level at the water intake point and the water level inside the tank.

This vortex phenomenon increases the stirring efficiency of the indoor liquid, causing oxidation, reduction, and
It promotes cross-type reactions, such as decomposition and precipitation, in which electrons are exchanged directly at the interface between the electrode and the wastewater to be treated, and secondary reactions, in which electrode reaction products such as adsorption, aggregation, and flotation, react with components in the wastewater to be treated. This will promote the reaction.

In addition, as the electrode reaction and secondary reaction progress, the floc attaches gas bubbles and moves out of the vortex motion region, floats up to the surface of the anode 6, and then ascends along this surface while becoming enlarged and floats to the water surface. . Hydrogen gas has a large reducing power and suppresses oxidation of the anode surface. Furthermore, since the flocs float along the anode surface, the anode surface is polished and no oxide film is attached. In FIG. 4, a shows the flocs floating along the surface of the active anode plate 6 in the channel 8, b shows the flocs leaving the channel 8 and floats to the upper part of the electrolytic treatment tank 2, and C shows the floating accumulation section 20. The flocs that floated to the surface are shown respectively.

The primary treated water from which most of the flocs have been removed in the first electrolytic treatment section 4 is sent to the flow path 18 between the inert anode plate 14 and the cathode plate 15 of the second treatment section 5, and is then sent to the first electrolytic treatment section. The flocs that could not be completely floated in Step 4 are attached to fine gas bubbles of 10 to 30 μm in size generated on the surface of the cathode plate 15, and are floated and separated against the water flow. Note that the floating speed of the flocs with debris attached at this time is about 20 m/hr, and the design is such that the falling speed in the flow path 18 of the secondary treated water is less than this. Therefore, the flocs <SS> remaining in the primary treated water are completely removed, and the treated water passes through one discharge channel and is discharged from the opening 19a at the discharge point.

On the other hand, the flocs decomposed in the first and second uniform solution processing sections 4.5 are accumulated in the floc flotation and accumulation section 20 in the upper part of the electrolytic treatment tank 2 in order from the bottom.

Approximately half of the accumulated thickness of the scum C formed by the accumulation of flocs is pushed above the water surface, so as the flocs are accumulated sequentially from the bottom, the top surface of the scum gradually rises, causing overflow. The scum passes over the weir 22 and flows into the scum recovery bit 21.

This overcoming is possible by setting the height of the overflow weir 22 to about 51 degrees or less higher than the water surface height in the electrolytic treatment section 2. In addition, if sufficient time is allowed to allow the scum to develop and get over it, the water content of the scum can be reduced to 80% or less.

In the above-mentioned embodiment, the electrolytic treatment is performed in two stages in the first and second uniform processing units, but it goes without saying that the electrolytic treatment may be performed in only the negative stage.

(Effects of the Invention) As described above, in the sewage treatment apparatus using the electrolytic treatment method of the present invention, negative and positive electrode plates facing each other are arranged in an inclined manner with the anode plate facing upward, so that the electrolytic action between the two electrode plates is reduced. By forcing the sewage to be treated to flow through the upwelling flow generated by movement occurs, and the vortex phenomenon increases the stirring efficiency in the flow path between the two electrodes, promoting electrode reactions and secondary reactions caused by electrode products. The process is uniformly applied to the entire treated wastewater, resulting in higher treatment efficiency. Furthermore, the active anode plate is always in contact with the highly reducing hydrogen gas generated on the cathode plate, and since the flocs are raised along the active anode plate while being in contact with it, oxidation between the anodes is suppressed and the surface is subjected to a polishing action, no oxide film is attached, and it can be used for a long time without the need for special polishing.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention. Figure 1 is a sectional view showing the overall outline, Figure 2 is a sectional view taken along line 9 - ■ in Figure 1, and Figure 3 is a cross-sectional view of the first electrolyte. FIG. 4 is an enlarged sectional view showing the operation in the treatment section, FIG. 4 is an enlarged sectional view showing the floc rising state, and FIG. 5 is a partially enlarged sectional view of the second electrolytic treatment section. a, b, c...floc, 1...water surface, 2...electrolytic treatment tank, 2c...bottom plate,
3... Partition plate, 4... First electrolytic treatment section, 5... Second electrolytic treatment section, 6... Active anode plate, 7... ... Cathode plate, 8 ... Water flow path to be treated, 9 ... Insulating substrate, 10 ... Electrode plate, 11 ... Bottom plate, 12. ...Water introduction channel to be treated, 12a...Tip opening, 13...
...Water port, 14...Inert anode plate, 5...
... Ifji electrode plate, 16 ... Insulating substrate, 7.
... Electrode plate, 18 ... Channel, 9 ...
...Discharge channel, 20...Floc floating accumulation section,
1... Scum collection pit, 22... Overflow weir.

Claims (1)

[Claims] A large number of active anode plates and cathode plates are arranged to face each other, and the space between the electrode plates is used as a flow path for wastewater to be treated.The wastewater to be treated is caused to flow through the flow path, and electrolytic treatment is performed during the flow. In the sewage purification device, the bipolar plates are inclined to make the flow path between the bipolar plates incline, and the anode plate is arranged on the upper side and the cathode plate is arranged on the bottom side so as to face each other, A water introduction passage to be treated is communicated with the lower end of the flow path, and a floc floating accumulation part is provided above the electrode plates, so that the wastewater to be treated is caused to flow by an upwelling flow due to electrolytic treatment between the electrode plates. A sewage purification device using an electrolytic treatment method.