JPH08182990A - Muddy water treating device - Google Patents

Abstract

PURPOSE: To provide a muddy water treating device capable of easily transporting to a building site or the like and stably executing the purifying treatment of muddy water for a long time. CONSTITUTION: Suspended particles contained in the muddy water is neutralized to flocculate by cations generated from an anode composed of an aluminum alloy plate in an electrode bath 2 and the water containing the flocculated floc is fed to a separation tank 3. The anode is prevented from being worn by switching over the anode to a cathode in the electrode bath 3 every fixed time. The separation tank 3 is composed of an outer cylinder 32 and an inner cylinder 31, the muddy water containing the floc flows out from a muddy water stream outlet in the inner cylinder 31 to the bottom of the outer cylinder 32 and the floc is deposited in the outer cylinder 32. The number of fine particles suspending in the supernatant is lowered by constantly depositing the floc up to a part upper than the position of the muddy water stream outlet in the inner cylinder 31 and using the deposited floc as a filter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a turbid water treatment device for removing suspended substances in turbid water generated in foundation works such as building works and discharging the turbid water.

[0002]

[Prior Art] Unlike effluent of a factory, turbid water generated by foundation work such as construction work is usually discharged for a short period of time and does not contain harmful metals, so sewage remains untreated. They drained into gutters and rivers, and installed a simple settling tank to drain the supernatant water. If turbid water is drained without being treated in this way, sludge will accumulate in the sewer pipes and rivers will be contaminated, which will have a large impact on the natural environment. It has been required by the prefectural pollution prevention regulations. As the purification treatment of this turbid water, coagulation and sedimentation treatment with chemicals is often adopted.

In general, suspended particles suspended in water are negatively charged and repel each other, so that they are stable in a dispersed state. Therefore, in the coagulation-sedimentation treatment with chemicals, suspended particles dispersed by adding a coagulant with a positive charge to turbid water are electrically neutralized to agglomerate the particles, increasing the diameter of the suspended particles and settling speed in water. Is a method of increasing. Aluminum sulfate, basic aluminum chloride, ferric chloride, etc. are used as the flocculant used in this flocculation-precipitation treatment. In addition, a polymer flocculant such as sodium alginate and polyacrylic amide is also used, and the floating particles are flocculated by utilizing the adsorptive crosslinking action between the particles.

As the coagulation-sedimentation processing apparatus, there is provided a horizontal processing apparatus having a mixing tank for mixing waste water and a coagulant, a floc formation tank for growing flocs, and a sedimentation tank for accumulating and flocculating the grown flocs. A vertical type processing device is used to recirculate flocs generated by mixing waste water and a flocculant.

[0005]

When the turbid water is purified by the coagulation-sedimentation treatment with a chemical as described above, the hydroxide of the chemical used as the coagulant and the chemical itself are discharged into a river or the like. However, there is a risk that the chemicals may cause environmental pollution and that the equipment will be large.

In order to prevent environmental pollution from being caused by such chemicals, a turbid water purifying apparatus for aggregating suspended particles in turbid water without using a coagulant is disclosed in, for example, JP-A-4-2982.
No. 84 publication. In this turbid water purification device, an anode electrode made of aluminum and a cathode electrode made of stainless steel are alternately arranged along a flow path of the turbid water, and cations generated from the anode electrode neutralize suspended particles in the turbid water. When this turbid water purification device is used, it is not necessary to add or purify the flocculant, but when used for a long time, the aluminum anode electrode is consumed and it is not easy to replace it.

The present invention has been made in order to eliminate such disadvantages, and an object thereof is to obtain a turbid water treatment apparatus which can be easily transported to a construction site or the like and can be stably used for a long time. .

[0008]

A turbid water treatment apparatus according to the present invention has an electrode tank, an electrode switching means, a separation tank and a floc discharge control means arranged in a subsequent stage of the electrode tank, and the electrode tank is made of aluminum. A plurality of electrodes made of an alloy plate and connected to the anode of the DC power source and the electrode connected to the cathode of the DC power source are arranged alternately along the flow direction of the muddy water, and the electrode switching means has a predetermined constant time. The polarity of each electrode is switched by switching the connection of the DC power source and each electrode for each, the separation tank has an inner cylinder and an outer cylinder, the inner cylinder is installed vertically inside the outer cylinder, and the muddy water inlet is provided at the upper end. The lower side wall is provided with a plurality of muddy water outlets in a plurality of stages in the vertical direction, a plurality of partition plates are horizontally mounted inside, and each partition plate has muddy water passages at different positions for adjacent partition plates. However, the outer cylinder has a tapered conical shape at the bottom and has a sludge discharge port at the lower end. An overflow outlet is provided at the upper end, a stirring blade is provided in the lower conical section, and a floc upper limit detection that determines the upper limit of floc accumulation is established between the upper overflow outlet and the muddy water outlet of the inner cylinder. The floc discharge control means discharges sludge containing flocs accumulated from the sludge discharge port under the outer cylinder while rotating the stirring blade when the floc upper limit detection means detects the flock accumulation height limit. Stop the sludge discharge when it reaches the time until the accumulated flocs detected and set in advance decrease from the flocculation limit height to the upper end position of the muddy water outlet of the inner cylinder. Is characterized by.

Flock lower limit detection means is provided at the upper end position of the muddy water outlet of the inner cylinder, and the flock discharge control means accumulates from the sludge discharge port at the bottom of the outer cylinder when the flock upper limit detection means detects the flock accumulation limit height. It is also possible to start the discharge of sludge including the above-mentioned flocs and stop the discharge of the sludge when the flocs lower limit detecting means reduces the flocs to the upper end position of the muddy water outlet of the inner cylinder.

[0010]

In the present invention, the suspended particles contained in the turbid water are neutralized with the cations generated from the anode electrode of the electrode tank to aggregate them, and the water containing the aggregated flocs is sent to the separation tank,
The flocs are allowed to settle and separate from water. The anode electrode and the cathode electrode of the electrode tank for aggregating the suspended particles contained in this turbid water are formed of an aluminum alloy plate, and an insulating coating A is formed on the electrode surface.
prevent l ₂ 0 ₃ film is formed. The corrosion resistance of aluminum is greatly affected by its purity, and generally, as the purity increases, the corrosion resistance also improves. Corrosion resistance of the aluminum by the protective action of Al ₂ 0 ₃ film generated on the surface. Thus purity is higher Al ₂ 0 ₃ film is formed easily, by an insulating film produced on the surface by using the pure aluminum electrode electrolytic efficiency is reduced. In order to prevent this decrease in electrolysis efficiency, Al
Constituting the anode electrode and the cathode electrode ₂ 0 ₃ film is formed hardly aluminum alloy plate.

As described above, when the aluminum alloy plate is used as an electrode for a long period of time, the anode electrode for generating cations is consumed. Therefore, the anode electrode is switched to the cathode electrode and the cathode electrode is switched to the anode electrode at regular intervals to suppress the consumption of the anode electrode.

Further, the separation tank is composed of an outer cylinder and an inner cylinder vertically provided in the outer cylinder, and the muddy water supplied from the muddy water inlet provided at the upper end of the inner cylinder is provided on a plurality of lower side walls. Forced outflow from the outlet to the bottom of the outer cylinder. When muddy water flows down in the inner cylinder, a plurality of partition plates prevent the flocs contained in the muddy water from being destroyed by a sudden drop.

The flocs in the turbid water flowing out to the lower part of the outer cylinder are successively settled and accumulated, and are accumulated from the position of the muddy water outlet of the inner cylinder to the upper part. By flowing muddy water into the accumulated flocs from the muddy water outlet of the inner cylinder, the flocs accumulating fine particles that are not aggregated to an appropriate size contained in the muddy water are captured as a filter and accumulated. Reduce the number of fine particles suspended in the supernatant water on the flocs. Therefore, the discharge amount of sludge in the lower part of the outer cylinder is controlled so that the flocs are always accumulated up to the upper position of the muddy water outlet of the inner cylinder.

[0014]

1 is a block diagram showing an embodiment of the present invention. As shown in the figure, the turbid water treatment device 1 has an electrode tank 2, a separation tank 3, a power supply device 4, and a control unit 5. The electrode tank 2 agglomerates suspended particles of suspended matter in turbid water sent from a turbid water source 6 such as an excavated portion of foundation work of building work directly or through a settling tank 7 to enlarge the particles. Yes, Figure 2
As shown in the perspective view of FIG. 2, a plurality of sheets are alternately arranged along the flow direction A of muddy water, and an anode electrode 21 connected to the anode of the power supply device 4 and a cathode electrode 22 connected to the cathode of the power supply device 4. And has a structure in which turbid water passes between the anode electrode 21 and the cathode electrode 22. Anode electrode 21 and cathode electrode 2
2 is formed of an aluminum alloy plate, and neutralizes and agglomerates the negatively charged soil particles floating in the turbid water by aluminum ions which are cations generated from the anode electrode 21.

The anode electrode 21 and the cathode electrode 22 are formed of an aluminum alloy plate in order to prevent the formation of an Al ₂ O ₃ film which is an insulating film on the surfaces of the anode electrode 21 and the cathode electrode 22. is there. That is, the corrosion resistance of aluminum is greatly influenced by the purity, and generally, as the purity increases, the corrosion resistance also improves. The corrosion resistance of this aluminum is due to the Al generated on the surface.
_{20 3 Due to} the protective effect of the film. Therefore, the higher the purity, the more easily the Al ₂ O ₃ film is formed, and when pure aluminum is used for the anode electrode 21 and the cathode electrode 22, the insulating film formed on the surface lowers the electrolysis efficiency. In order to prevent the deterioration of the electrolysis efficiency, the anode electrode 21 and the cathode electrode 22 are formed of an aluminum alloy plate on which an Al ₂ O ₃ film is hard to form, so that the suspended particles in turbid water are aggregated stably for a long time. is there.

The muddy water inflow side of the anode electrode 21 and the cathode electrode 22 is connected to the treated water outlet of the separation tank 3, and a shower for spraying water on the muddy water surface flowing between the anode electrode 21 and the cathode electrode 22. -Spouting means 23 are provided.

The muddy water outlet 24 of the electrode tank 2 is connected to the separation tank 3. The separation tank 3 has a vertical inner cylinder 31 and an outer cylinder 32. The inner cylinder 31 is vertically provided in the outer cylinder 32, and has a muddy water inlet 33 connected to the muddy water outlet 24 of the electrode tank 2 at the upper end and a lower end as shown in the cross-sectional view of FIG. A plurality of muddy water outlets 34 are provided on the lower side wall in a zigzag manner in the vertical direction in a plurality of stages. A plurality of partition plates 35 are horizontally mounted inside the inner cylinder 31.
Has muddy water passages 36 at different positions for adjacent partition plates 35. The outer cylinder 32 has a tapered conical shape at the bottom, a sludge discharge port 38 to which a motor-operated valve 37 is connected at the lower end, and an overflow water discharge port 39 at the upper end. The stirring blade 40 is provided in the lower conical portion. The stirring blade 40 is connected to a stirring motor 41 installed at the upper end of the separation tank 3 via a gear mechanism 42 and a drive shaft 43 penetrating the inner cylinder 31. Further, a flock upper limit detecting means 44 for determining a flock accumulation upper limit position is provided at an intermediate portion between the upper overflow water discharge port 39 and the muddy water outlet 34 of the inner cylinder 31. The flock upper limit detecting means 44 is, for example, a light transmission type sensor in which a light projector 44a and a light receiver 44b are housed in a protective tube 44c, respectively, and detects the upper limit level of the flock accumulated in the outer cylinder 32.

The power supply device 4 has a portable generator and a rectifying device, and supplies electric power to the electrode tank 2 and the separation tank 3 via the control unit 5. As shown in the block diagram of FIG. 4, the control unit 5 has an electrode switching unit 51, a flock discharge control unit 52, and a discharge timer 53. The flock discharge control unit 52 drives the stirring motor 41 and the motor-operated valve 37 when the flock upper limit detection means 44 detects the flocculation limit height, and rotates the stirring blade 40 to rotate the stirring blade 40 and the sludge discharge port of the outer cylinder 32. The discharge of sludge including flocs accumulated from 38 is started. After that, the flock discharge control unit 52 detects the time until the accumulated flock, which is detected in advance and set in the discharge timer 53, decreases from the accumulation limit height of the flock to the upper end position of the muddy water outlet 34 of the inner cylinder 31. When reaching the
The driving of the motor 41 and the motor-operated valve 37 is stopped to stop the discharge of sludge.

Next, the operation of the muddy water treatment apparatus 1 configured as described above will be described. A suction horn 8 is installed on the turbid water generation source 6 such as an excavated portion of the foundation work of the construction work, and the turbid water generated by the turbid water generation source 6 is sent to the electrode tank 2. When a large amount of sand is contained in the turbid water sent to the electrode tank 2, the sand contained in the turbid water is precipitated in the settling tank 7 so that the turbid water containing no sand is converted into the electrode tank 2
Send to The anode electrode 2 of the electrode tank 2 to which this muddy water is sent
1 and the cathode electrode 22 from the power supply device 4 to the electrode switching means 51.
Voltage is applied through the anode electrode 21 and the cathode electrode 22.
Aluminum cations are generated from the anode electrode 21 in the turbid water flowing between them. The generated aluminum cations neutralize and agglomerate the negatively charged soil particles floating in the turbid water to increase the particle size and form flocs.
When forming the flock in this way, the power supply 4 to 1.
The aggregation effect was able to be demonstrated by supplying the electric power of the current density of ² mA / cm < ² > -1.6 mA / cm < ² >.

The turbid water in which the suspended particles are flocculated as described above is sent to the separation tank 3. On the other hand, bubbles are generated during the electrolytic action in the electrode tank 2, and the generated bubbles are combined with some of the fine particles contained in the muddy water to form a scum on the surface of the electrode tank 2 to float and stagnant. This scum becomes thick and hard as soon as a layer is formed, and the electrolytic action is stagnated. Then, water is sprayed from the shower spouting means 23 onto the surface of the scum, the scum is finely decomposed and contained in the turbid water, and the scum is sent to the separation tank 3 together with the flocculated suspended particles.

The muddy water that has flowed into the muddy water inlet 33 of the inner cylinder 31 of the separation tank 3 passes through the inner cylinder 31 and flows out from a plurality of muddy water outlets 34 on the lower side wall to the lower part of the outer cylinder 32. When muddy water flows down in the inner cylinder 31, the muddy water passage 36 is provided at a different position.
The plurality of partition plates 35 having the above structure prevent the turbid water from abruptly dropping and prevent the flocs contained in the turbid water from being destroyed.

The flocs in the turbid water sent into the outer cylinder 32 settle in the turbid water, accumulate in the lower part of the outer cylinder 32, and are separated from the clear water. Settling velocity V when this floc settles in water
Is generally the Stokes equation V = g (ρs−ρ) d ² / 18μ
Can be represented by Here, g is the acceleration of gravity, ρs is the density of flocs, ρ is the density of water, d is the diameter of the flocs, and μ is the viscosity coefficient of water. Therefore, the larger the diameter d of the floc particles is, the faster the sedimentation velocity V is, and the sedimentation can be performed in a short time.

When turbid water is continuously fed into the outer cylinder 32, the supernatant water separated from the flocs flows out from the overflow outlet 39 provided at the upper end of the outer cylinder 32 and is discharged to the sewer gutter and the drainage channel 10 of the river. It When muddy water is continuously fed into the outer cylinder 32 in this way, the deposition thickness of the flocs gradually increases and accumulates up to a position above the muddy water outlet 34 of the inner cylinder 31. In this way, when the flocs are accumulated up to the position above the muddy water outlet 34 of the inner cylinder 31, the treatment effect can be further enhanced. That is, when turbid water is caused to flow out into the accumulated flocs, the flocs accumulating fine particles contained in the turbid water that are not aggregated to an appropriate size are captured and deposited as a filter. Therefore, it is possible to reduce the number of fine particles floating in the supernatant water flowing out from the overflow outlet 39.

When the accumulated thickness of the flocs in the outer cylinder 32 increases and the upper end of the accumulated flocs is detected by the floc upper limit detection means 44, the floc discharge control unit 52 causes the flocculation control unit 52 to continue stirring the muddy water. -The motor 41 and the motor-operated valve 37 are driven to start discharging sludge including flocs accumulated from the sludge discharge port 38 of the outer cylinder 32 while rotating the stirring blade 40. When the sludge is discharged, since the lower part of the outer cylinder 32 has a tapered conical shape, the sludge can be easily discharged. In addition, by rotating the stirring blade 40 to rotate the discharged sludge, the sludge attached to the lower wall surface of the outer cylinder 32 can be separated and collected.

The floc discharge control unit 52 reduces the accumulated flocs set in the discharge timer 53 after the sludge collection is started from the flocculation limit height to the upper end position of the muddy water outlet 34 of the inner cylinder 31. When the time up to this is reached, the drive of the stirring motor 41 and the motor-operated valve 37 is stopped to stop the discharge of sludge. By controlling the accumulated thickness of the flocs so that the upper end of the accumulated flocs is always located above the muddy water outlet 34 of the inner cylinder 31,
The amount of soil particles in the treated water discharged from the outer cylinder 32 can be made minute. As a result of measuring the amount of suspended solids (SS) in the treated water when treating the turbid water generated at the construction site in this way, the amount of suspended solids (SS) can be reduced to about 10 ppm, which is Amount of suspended solids specified by various standards such as environmental standards and drainage standards of the Water Pollution Control Law (S
It was possible to process below the standard value of S).

The sludge collected is collected by an ordinary filter.
Dewater with a press or centrifuge to a water content of about 80%.

The above process is continuously performed, and after a predetermined time has passed, the operator operates the electrode switching means 51 to switch the polarities of the anode electrode 21 and the cathode electrode 22 of the electrode tank 2. That is, when the aluminum alloy plate is used as an electrode for a long period of time, the electrode generating cations is consumed. Therefore, by switching the polarities of the anode electrode 21 and the cathode electrode 22 at regular intervals, it is possible to suppress the consumption of the electrodes, and it is possible to perform the treatment stably for a long period of time.

In the above embodiment, when sludge is collected from the outer cylinder 32, sludge discharge control is performed according to the time set in the discharge timer 53, and the upper end of the accumulated flocs is always the muddy water outlet of the inner cylinder 31. Although the case where it is controlled to be positioned above the 34 is described, the muddy water outlet 3 of the inner cylinder 31 is described.
A floc lower limit detecting means similar to the flock upper limit detecting means 44 may be provided at the upper end position of 4 and the discharge of sludge may be stopped when the upper surface of the accumulated flocs is below the installation position of the floc lower limit detecting means. .

[0029]

As described above, according to the present invention, the electrode of the electrode tank for aggregating the suspended particles contained in the turbid water is formed of the aluminum alloy plate to prevent the formation of the insulating film on the surface and the electrode. It is possible to stably agglomerate the suspended particles contained in the turbid water for a long period of time because the polarity of the anode is switched at regular intervals to suppress the consumption of the anode electrode.

Further, the separation tank is composed of an outer cylinder and an inner cylinder vertically provided in the outer cylinder, and muddy water supplied from a muddy water inlet provided at the upper end of the inner cylinder is provided on a plurality of lower muddy waters. When forcibly flowing out from the outlet to the lower part of the outer cylinder, abrupt drops of muddy water are suppressed by multiple partition plates that have muddy water passages at different positions. It is possible to prevent a large amount of flock from being destroyed and send a large flock to the outer cylinder. Therefore, flocs can be settled and deposited in a short time.

Further, since the flocs are always deposited in the outer cylinder from the position of the muddy water outlet of the inner cylinder to the upper part, the flocs containing the fine particles contained in the muddy water and not agglomerated to an appropriate size are deposited. Can be captured as a filter, the number of fine particles floating in the treated water can be reduced, the treatment capacity can be improved, and environmental pollution can be prevented.

Further, since the electrode tank and the separation tank can be easily separated and the processing capacity can be enhanced, the whole apparatus can be downsized and easily transported to various construction sites. .

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view showing the configuration of the electrode tank of the above embodiment.

FIG. 3 is a cross-sectional view showing the structure of the separation tank of the above embodiment.

FIG. 4 is a block diagram showing a control unit of the above embodiment.

[Explanation of symbols]

 1 Turbid Water Treatment Device 2 Electrode Tank 3 Separation Tank 4 Power Supply Device 5 Control Unit 21 Anode Electrode 22 Cathode Electrode 23 Shower Ejection Means 31 Inner Cylinder 32 Outer Cylinder 34 Turbid Water Outlet 35 Partition Plate 40 Stirring Blade 44 Flock Upper Limit Detecting 51 Electrode Switching means 52 Flock discharge control unit 53 Discharge timer

Claims (2)

[Claims] 1. An electrode tank, an electrode switching means, and a separation tank and a floc discharge control means arranged in the latter stage of the electrode tank, wherein the electrode tank is made of an aluminum alloy plate and connected to an anode of a DC power source. Electrodes and a plurality of electrodes connected to the cathode of the DC power supply are alternately arranged along the flow direction of the muddy water, and the electrode switching means switches the connection between the DC power supply and each electrode at a predetermined fixed time. The polarity of the electrodes is switched, the separation tank has an inner cylinder and an outer cylinder, the inner cylinder is installed vertically in the outer cylinder, the upper end has a muddy water inlet, and the lower sidewall has a plurality of muddy water outlets vertically. It is installed in multiple stages in the direction, a plurality of partition plates are installed horizontally, each partition plate has a muddy water passage at a different position for each adjacent partition plate, and the outer cylinder has a conical shape with a tapered lower part. , Has a sludge discharge port at the lower end, an overflow water discharge port at the upper end, and a conical section at the bottom A stirring blade is provided in the upper part, and a floc upper limit detecting means for determining a flock accumulation upper limit position is provided in an intermediate portion between the upper overflow water outlet and the muddy water outlet of the inner cylinder. When the maximum sedimentation height of flocs is detected with, the sludge including the flocs accumulated is started from the sludge discharge port under the outer cylinder while rotating the stirring blade, and the accumulated flocs detected and set in advance are started. The turbid water treatment device is characterized in that the sludge discharge is stopped when the time it takes for the flock to reach the upper end position of the turbid water outlet of the inner cylinder from the height limit of accumulation of flocs. 2. A sludge discharge port in the lower part of the outer cylinder when the floc lower limit detection means is provided at the upper end position of the muddy water outlet of the inner cylinder, and the flock discharge control means detects the flock accumulation limit height by the flock upper limit detection means. The muddy water treatment device according to claim 1, wherein the sludge including the accumulated flocs is started to be discharged, and the sludge discharge is stopped when the floc lower limit detecting means reduces the amount of the sludge to the upper end position of the muddy water outlet of the inner cylinder.