JP2623052B2 - Coagulation separation device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aggregating / separating apparatus for aggregating and separating fine solid particles and oil particles contained in industrial waste liquid and the like.

[0002]

2. Description of the Related Art For example, very fine solid particles are mixed in a washing waste liquid discharged from a washing step in coating an industrial product. Conventionally, in order to separate solid particles from this kind of waste liquid, generally, a coagulant such as aluminum sulfate or iron sulfate or a neutralizing agent is put into the waste liquid, and the particles in the liquid are coagulated and precipitated. They are separated from the effluent.

[0003]

However, when coagulating and separating solid particles using a coagulant or a neutralizing agent, equipment such as a coagulant charging tank, a neutralizing agent charging tank, and a sedimentation tank are required. It is necessary to provide a plurality of tanks in the form, and there is a problem that installation space and equipment cost increase.

[0004] Further, when the flocculant is introduced into the waste liquid and subjected to the flocculation treatment, the flocculant itself may be converted into sludge in the tank, and in some cases, the sludge due to the flocculant is less than the solid matter in the waste liquid. A much larger amount was generated, and there was a problem that a more complicated removal process was required to remove the sludge.

[0005] An apparatus for filtering solid particles from waste liquid using a special filter is also used.
The separation efficiency is poor, the filter needs to be replaced frequently, and colloidal particles having high stability cannot be separated well by filtration.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and can efficiently aggregate and separate solid particles and minute oil droplets from a liquid to be treated without using a chemical. It is an object of the present invention to provide a coagulation / separation device that can be configured as a small facility.

[0007]

In order to achieve the above object, an agglomeration / separation apparatus according to the present invention comprises a processing tank for storing a liquid to be processed, and a plurality of electrode plates disposed at intervals in the processing tank. And a power supply for applying an AC / high-frequency voltage between the electrode plates or between the electrode plate and the tank wall, wherein the frequency of the power supply is 1 k
Hz to 500 kHz , the voltage is set to 20V ,
A high-frequency electric field is applied to the liquid to be treated from the power supply device via the electrode plate to neutralize the interfacial electrokinetic potential of the suspended particles in the liquid to be treated, and to aggregate and separate solid particles and oil particles from the liquid to be treated. The point is to do.

[0008]

[Function / Effect] In the coagulation / separation apparatus thus configured, a high-frequency electric field is applied to the liquid to be treated in the treatment layer by applying an AC / high-frequency voltage between the electrode plates or between the electrode plate and the tank wall. The high-frequency electric field causes the solid particles in the liquid to vibrate, neutralizes the electrokinetic potential of the particles, and the solid particles aggregate. At the same time, the metal ions eluted from the electrode plate react with the hydroxide ions in the liquid to form flocs, and agglomerate while entraining the solid particles in the liquid, and flocs, that is, aggregates, precipitate and are separated from the liquid. . On the other hand, the electrolysis that occurs in the liquid to be treated is effectively suppressed by using a high frequency and setting the voltage to a relatively low value of 20V .

Further, in the case of a waste fluid such as a water-soluble cutting fluid contained in the form of an emulsion, that is, fine oil droplets, when a high-frequency electric field is applied, the electrokinetic potential of the oil in the liquid is neutralized by the electric field, and Coagulation and coarsening of the droplets are promoted.

As described above, the high-frequency electric field is applied to the liquid to be treated to coagulate and separate the solid particles and the fine oil droplets of the emulsion.
Equipment such as a tank is miniaturized, and can be easily treated without generating sludge. Even in the case of highly stable colloid particles, particles in a liquid can be efficiently aggregated and separated.

[0011]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a longitudinal sectional view of the coagulation / separation apparatus, and FIG. 2 is a transverse sectional view thereof. This coagulation separation device,
It comprises a processing tank 1 for storing a waste liquid to be processed, and a power supply device 2 for applying an AC / high-frequency voltage between the electrode plates 5 and 6 in the processing tank 1 to apply an electric field to the liquid to be processed.

The processing tank 1 is provided with a supply port 3 for supplying a liquid to be treated on one end wall, and a supply pipe is connected to the supply port 3. An electrode chamber 4 is formed inside the processing tank 1 near the supply port 3, and a plurality of electrode plates 5 and 6 are alternately vertically arranged in the electrode chamber 4 at regular intervals.

The electrode plate 5 is fixed to the wall of the processing tank 1 via the insulating plate 9, and the electrode 6 is fixed directly to the processing tank 1. A space is formed around the free end of each of the electrode plates 5 and 6 to form a passage for the liquid to be treated. The electrode chamber 4 in the processing tank 1
A space is formed at the bottom of the for storing the sediment that has aggregated and settled. The electrode plates 5 and 6 are made of a conductive metal such as iron or aluminum.

The other end in the processing tank 1 is partitioned by a partition plate 7 having a low height rising from the bottom, and a partition chamber 8 is formed next to the electrode chamber 4. The structure is such that the liquid to be treated after the separation has flowed into the partitioning chamber 8.

A discharge port 11 is formed at the other end of the processing tank 1, that is, at a lower portion of the side wall of the partitioning chamber 8, and the discharge pipe 11 is provided at the discharge port 11.
0 is connected. The discharge pipe 10 has a structure that rises from the discharge port 11 to a liquid level and allows the liquid to be processed that has overflowed from the liquid level to flow out.

As shown in FIG. 3, the power supply device 2 includes a high-frequency signal generator 15 for generating a high-frequency signal, a voltage amplifier 16 for inputting the high-frequency signal output from the high-frequency signal generator 15 and amplifying the voltage, A current amplifier 17 for current-amplifying a signal output from the amplifier 16;
It is composed of The output side of the current amplifier 17 is the electrode chamber 4
Connected to the inner electrode plates 5 and 6.

The high-frequency signal generator 15 has a high-frequency oscillator for generating an AC / high-frequency signal of about 1 kHz to about 500 kHz, and oscillates and outputs an arbitrarily settable frequency signal. The high-frequency signal generator 15 is switchably provided with a sine wave output circuit that outputs an oscillated high-frequency signal as a sine wave, a rectangular wave output circuit that outputs a square wave, and a saw-tooth wave output circuit that outputs a saw-tooth wave. Then, a high-frequency signal of the selected waveform is output.

When a liquid to be treated, such as a waste liquid, is placed in the treatment tank 1 and subjected to agglomeration by applying an electric field.
The conductivity of the liquid changes. Therefore, the value of the current flowing between the electrode plates 5 and 6 deviates from the value of the current at which the best aggregation efficiency is exhibited. Therefore, a current control circuit 18 for controlling the output current of the current amplifier 17 is provided. The current control circuit 18 detects the output current value of the current amplifier 17 and compares the detected current value with a preset current set value. When the current values are different, a voltage adjustment signal for adjusting the voltage is output to the voltage amplifier 16 to adjust the voltage, so that the output current value of the current amplifier 17 is adjusted to the current set value. The current control circuit 18 also operates as a protection circuit that shuts off the output of the current amplifier 17 when the load current rises abnormally due to a short circuit between the electrodes or the like.

Next, the operation of the coagulation / separation apparatus having the above configuration will be described.

For example, waste liquid (liquid to be treated containing fine solid particles) discharged from the washing step in the coating step is
It is supplied from a supply port 3 through a pump or the like into the electrode chamber 4 of the processing tank 1 until it reaches a predetermined level. And the power supply 2
Is started, and a predetermined alternating current / high frequency voltage is applied between the electrode plates 5 and 6 to start the coagulation separation process.

The AC / high-frequency power supplied to the electrode plates 5 and 6 at this time has a frequency of about 1 kHz to about 500 kHz,
The current is about 0.05A to about 2A, and the voltage is about 20V. The higher the voltage is, the better the coagulation efficiency is,
It is set to about 20V for safety.

The waste liquid that has entered the electrode chamber 4 through the supply port 3 is subjected to the action of an electric field generated by the AC / high-frequency voltage applied between the electrode plates 5 and 6, and the solid particles in the liquid are vibrated by the high-frequency electric field. At the same time, the electrokinetic potential of the particles is neutralized,
The solid particles agglomerate. Further, the metal ions eluted from the electrode plates 5 and 6 react with the hydroxide ions in the liquid to form flocs, and agglomerate while entraining the solid particles in the liquid, and flocs, that is, aggregates precipitate.

After the solid particles are separated, the liquid to be treated passes through the partition plate 7, enters the partition chamber 8, and is discharged from the partition chamber 8 through the discharge pipe 10. The floc settled at the bottom of the electrode chamber 4 is discharged by an appropriate method after the treatment.

As described above, an alternating current / high frequency voltage is applied between the electrode plates 5 and 6 to cause a high frequency electric field to act on the liquid to be treated. Aggregation can be promoted even with high colloid particles. Also, use alternating current and high frequency
By setting the voltage to a relatively low value of 20 V, it is possible to minimize the electrolysis of the liquid to be treated and minimize the consumption of the electrode plate.

On the other hand, if an oil receiving portion for receiving the floating oil is provided above the partition plate 7 in the processing tank 1 having the above-described structure, it is possible to process a waste liquid mixed with an oil such as a water-soluble cutting fluid. .

That is, the waste liquid of the water-soluble cutting fluid contains a large amount of a surfactant together with the oil, and the oil is contained in the form of an emulsion, that is, fine oil droplets. When a high-frequency electric field is applied, the electric field neutralizes the electrokinetic potential of the oil in the liquid and promotes the aggregation and coarsening of the oil droplets. As a result, the separated oil droplets become
Surface, the surface of high oil concentration appears on the surface,
The lower part is almost water and separated. Therefore, if the oil droplets floating on the upper layer are received and discharged by the oil receiving portion, even the oil component in the emulsified waste liquid can be efficiently aggregated and separated.

According to experiments, in the case of waste liquid mixed with solid particles, the best AC / high-frequency power supplied to the electrode plates 5 and 6 was obtained when the frequency was 60 kHz, the current was 0.9 A, and the voltage was 20 V. A coagulation / separation effect was obtained. In the case of a waste liquid containing an emulsion, alternating current / high frequency power supplied to the electrode plates 5 and 6 is supplied at a frequency of 60 kHz and a current of 1.0.
A, when the voltage was 20 V, the best aggregation / separation effect was obtained.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a treatment tank of a coagulation / separation apparatus showing one embodiment of the present invention.

FIG. 2 is a horizontal sectional view thereof.

FIG. 3 is a block diagram of a power supply device of the coagulation separation device.

[Explanation of symbols]

 1-treatment tank, 2-power supply device, 4-electrode chamber, 5,6-electrode plate.

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-52-42468 (JP, A) JP-B-56-23657 (JP, B2)

Claims (1)

(57) [Claims] 1. A treatment tank for storing a liquid to be treated, a plurality of electrode plates arranged in the treatment tank at intervals, and an alternating current / high frequency wave between the electrode plates or between the electrode plate and the tank wall. And a power supply for applying a voltage, wherein the frequency of the power supply is 1 kHz to 500 kHz.
The voltage is set to 20 V , and a high-frequency electric field is applied to the liquid to be processed from the power supply device via the electrode plate to neutralize the interfacial electrokinetic potential of the suspended particles in the liquid to be processed. An agglomeration / separation apparatus, which agglomerates and separates solid particles and oil particles from a treatment liquid.