KR100428855B1 - Wastewater treatment apparatus in use of the underwater discharge by low-voltage pulsed power - Google Patents

Abstract

Disclosed is a low voltage high frequency pulsed power supply with instantaneous high power to induce electrolytic redox and / or agglomeration of pollutants in wastewater, which can be used to quickly and efficiently purify wastewater. It relates to a wastewater treatment device. The present invention is a power supply for supplying a low voltage high frequency pulse power supply of instantaneous large current; Electrodes having an internal high frequency pulse power source to generate a discharge, and comprises a reaction tank for purifying contaminants in the wastewater introduced into the interior by redox reaction and / or flocculation reaction. Preferably, further comprising a circulation pump for circulating the waste water during the reaction treatment in the reaction tank to promote the redox reaction and / or aggregation reaction while the contaminants in the waste water evenly react.

Description

Wastewater treatment apparatus in use of the underwater discharge by low-voltage pulsed power

The present invention relates to an apparatus for purifying contaminants in wastewater, and more particularly, by supplying a low voltage high frequency pulse power source having instantaneous high power to induce electrolytic redox reactions and / or flocculation reactions in wastewater The present invention relates to a wastewater treatment apparatus using an underwater discharge of a low voltage pulse that can be quickly and efficiently purified.

In general, electrochemical wastewater treatment methods can be broadly classified into electrolysis technology using low voltage direct current (DC), electroaggregation technology, electrolysis technology using high voltage alternating current (AC), and electrolysis technology using high voltage pulse.

First, since the electrolytic technology using low voltage DC is operated at a low voltage of less than 10V, an electrolyte may be added to facilitate the electrolysis, and a plurality of electrode plates should be installed while shortening the electrode spacing, and preventing the elution of the electrode. In order to develop an insoluble electrode with strong electrochemical durability, it is necessary to make an indispensable electrode, so the cost increases exponentially as the installation area increases. In addition, the processing time becomes long because it must be operated under a low voltage condition. In particular, it is difficult to directly discharge electrons with energy within 10 eV for the removal of pollutants and organic materials, and the removal reaction is mainly carried out by ozone or hydroxide ions generated at the interface between the electrode and the wastewater. There is a falling lung.

Secondly, a coagulation technique using low voltage DC is used to coagulate heavy metals and solids by forming a hydrate using Fe and Al as the electrode material, and is widely used with chemical coagulant treatment technology. In such a flocculation technique, the treatment efficiency for organic substances or salts such as nitrogen and phosphorus is very small.

Third, electrolytic technology using high voltage AC is a technology that removes contaminants in wastewater by inducing high voltage discharge (barrier discharge) in water by applying an electrode with an insulator having a high dielectric constant to increase resistance. This technology has good treatment efficiency of organic materials in the wastewater, but due to the high conductivity of the wastewater, the current is concentrated to the point where insulation is the weakest during underwater discharge, causing the insulator to be destroyed. Since such devices adopt expensive insulators, the manufacturing cost increases as the installation area increases, and the problem of overcoming the problem of the insulators being destroyed is challenged.

Fourth, the electrolytic technique using the high voltage pulse is to install the discharge electrode in the water, the water treatment is made by the redox reaction by the radical generated along with the direct removal of the pollutant by the discharge electron. However, these technologies are very high in conductivity (approximately 1 ms / cm or more) and very low in resistance, making it difficult to apply high voltages. have. Even if this technology is applied to general water treatment with conductivity of 100㎲ / cm, the filling capacity of liquid phase is very large, so the charging capacity of power output part should be made very large so that high voltage is maintained for a certain time in liquid medium. The manufacturing cost is very high. For example, US SUI uses pulse shock as a technology for breaking down the cell walls of microscopic bacterial cysts in water. Thus, underwater discharge technology using high voltage pulse power is mainly used for special purposes. In the device using such a high voltage pulse, complicated insulation processing is required in terms of stability for high voltage application, resulting in an increase in manufacturing cost. Therefore, it is advantageous in this respect to apply a low voltage rather than a high voltage when applying pulsed power to wastewater treatment.

Accordingly, an object of the present invention is to solve the above-mentioned drawbacks, by supplying a low voltage high frequency pulse power supply with instantaneous high power to induce electrolytic redox reaction and / or flocculation reaction of the contaminants in the wastewater to The present invention provides a wastewater treatment apparatus using underwater discharge of low voltage pulses that can be quickly and efficiently purged.

Detailed description of the embodiments of the present invention will be made with reference to the accompanying drawings, in which numerals designate corresponding parts in the drawings.

1 is an overall configuration diagram of a wastewater treatment apparatus using underwater discharge of a low voltage pulse according to the present invention,

2A and 2B are front and side cross-sectional views of the porous porous electrode plate illustrated in FIG. 1,

3 is a view showing in detail the shape of the discharge needle shown in Figure 2b,

4A and 4B are front views and side cross-sectional views of the porous electrode plate shown in FIG. 1,

5 is a comparison table of the energy input efficiency according to the shape of the electrode,

6 is a comparison table of the energy input efficiency according to the distance between the paired electrodes,

7 is a waveform diagram of a pulse power source applied to an electrode for confirming instantaneous large power.

** Explanation of symbols for main parts of drawings **

10: power supply unit 20: reactor

30: porous porous electrode plate 32: discharge hole

34: discharge needle 40: porous electrode plate

42: discharge hole 60: injection tube

62: supply control valve 70: discharge pipe

72: discharge control valve 80: control unit

90: water level regulator 100: circulation pump

Wastewater treatment apparatus using an underwater discharge of a low voltage pulse according to the present invention for achieving the above object is a power supply for supplying a low voltage high frequency pulse power of instantaneous large current; And a reactor configured to receive the high frequency pulse power to generate discharge therein and to purify contaminants in the wastewater introduced therein by a redox reaction and / or an agglomeration reaction, wherein the reactor includes wastewater. An injection pipe for injecting the inside and a discharge pipe for discharging the purified water purified therein to the outside, wherein the injection pipe has a supply control valve for controlling the inflow of waste water and the discharge pipe for controlling the discharge of purified water It is characterized in that the control valve is provided.

The redox reaction can be applied to waste water such as cyanide, organic chemicals, ammonia nitrogen, nitrate nitrogen or organic wastes, sewage, livestock wastes and industrial wastes. It can be applied to many industrial wastewater and livestock wastewater.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is an overall configuration diagram of a wastewater treatment apparatus using underwater discharge of a low voltage pulse according to the present invention.

As shown in the drawing, the apparatus includes a power supply section 10 for supplying a low voltage high frequency pulse power supply of instantaneous large current. The high frequency pulse power output from the power supply unit 10 emits electrons having sufficient energy to remove contaminants in the wastewater with instantaneous large power of several tens of kW or less. It is equipped with the reaction tank 20 which receives this low voltage high frequency pulse power supply, and processes the contaminant in the wastewater which flowed in. In the reactor 20, a plurality of electrodes are arranged at regular intervals. The electrodes are composed of a porous porous electrode plate 30 and a porous electrode plate 40 which are arranged in pairs and spaced apart at predetermined intervals in the reaction tank 20. The paired porous porous electrode plate 30 and the porous electrode plate 40 are used as one positive electrode (+) and the other negative electrode (-), and a plurality of pairs are perpendicular to the reactor 20 as shown. It is arranged. Detailed structures of the porous porous electrode plate 30 and the porous electrode plate 40 will be described later with reference to FIGS. 3A to 5B. Of course, the high frequency pulsed power of the low voltage generated by the power supply unit 10 is supplied to the porous porous electrode plate 30 and the porous electrode plate 40.

As illustrated, the electrode is efficiently and preferably arranged so that the porous porous electrode plate 30 and the porous electrode plate 40 are paired and become the positive electrode and the negative electrode, respectively. The same type or different types of porous electrode plates and wire mesh electrode plates may be configured in pairs. That is, a pair of porous electrode plates may be used as a positive electrode and a negative electrode, or a pair of porous electrode plates may be used. Furthermore, a pair of wire mesh electrode plates may be used. In addition, different types of porous porous electrode plates and wire mesh electrode plates may be used as the positive electrode and the negative electrode, or a porous electrode plate and a wire mesh electrode plate may be used. Furthermore, by coating a catalyst or a photocatalyst on the surface of the electrode plates in contact with the wastewater, the reaction by the discharge and the reaction by the catalyst proceed in combination to increase the reaction efficiency and to suppress the elution of the electrode. You can reap.

The electrode plates can be predominantly induced by the redox reaction if made of insoluble materials such as Ti, SUS, and can lead to the coagulation reaction by using eluted electrodes such as Fe, Al. Therefore, when there are a lot of suspended solids such as heavy metals or phosphorus as wastewater pollutants, an elutable electrode such as Fe or Al is used as the positive electrode, and when there are a lot of nitrogen and organic substances, an insoluble electrode such as Ti or SUS is used. Is preferably used as the positive electrode (+). In order to induce two reactions at the same time, one of the plurality of positive / negative electrode pairs arranged may be an insoluble electrode as a positive electrode and an eluting electrode as a positive electrode. The thickness of the electrode plate is approximately 1 ~ 30mm is appropriate, in the case of agglomeration it is better to use a thicker than this.

Waste water to be purified from the outside in the reaction tank 20 is injected through the injection pipe 60, the purified water is discharged to the outside through the discharge pipe (70). The inlet pipe 60 is provided with a supply control valve 62 for controlling the inflow of wastewater to control the supply of wastewater so that a constant amount is always present in the reaction tank 20, and the discharge pipe 70 has wastewater in the reaction tank 20. When it is purified, a discharge control valve 72 for discharging to the outside is installed. The supply control valve 62 and the discharge control valve 72 are controlled by the controller 80 of the present apparatus. The reactor 20 is also equipped with a water level regulator 90, when the wastewater flowing into the reactor 20 reaches a certain level, it sends a water level signal to the controller 80, the controller 80 closes the supply control valve 62. By controlling the waste water is no longer supplied into the reaction tank (20). In addition, the reaction tank 20 is provided with a circulation pump 100 for circulating wastewater during reaction treatment to promote a redox reaction and / or agglomeration reaction while the medium is uniformly reacted.

The above-described level controller 90 is preferably configured as a level sensor, and the controller 80 receives the wastewater level value in the reaction tank 20 detected by the level controller 90 and controls the supply based on the detected value. By driving the valve 62 to maintain a constant water level in the reaction tank 20, and driving the circulation pump 100 during the wastewater treatment in the reaction tank 20 to promote the reaction by evenly reacting all the sections of the wastewater, After the treatment is completed, the discharge control valve 72 is opened to discharge the purified water to the outside.

2A and 2B are front views and side cross-sectional views of the porous porous electrode plate illustrated in FIG. 1, and FIG. 3 is a view showing details of the shape of the discharge needle illustrated in FIG. 2B.

As shown in FIGS. 2A and 2B, the porous porous electrode plate 30 mounted in the reaction vessel has discharge holes 32 formed in the shape of a checker board, and discharge needles 34 protrude innumerably between the discharge holes. have. The discharge needle 34 serves to induce a high electric field by raising the output value of the voltage. That is, when the radius of curvature of the end 34a of the discharge needle 34 is R and the input voltage is Vo, the electric field E is obtained by the following equation,

When the radius of curvature R of the end of the discharge needle 34 is less than 1mm, the actual output voltage (V) is raised to induce a high electric field (V / m). For example, if the radius of curvature is 0.2mm and the input voltage (Vo) is 200V, the electric field induces 100kV / m and the output voltage of 100kV is obtained. Therefore, it is important to make the radius of curvature of the discharge needle 34 as small as possible to increase the wastewater treatment efficiency.

On the other hand, the discharge hole 32 is suitable about 20mm in diameter, and may be appropriately varied within the range of about 1/100 to 100 times as the size of the device is increased or decreased.

4A and 4B are front and side cross-sectional views of the porous electrode plate shown in FIG. 1, and as shown, the discharge holes 42 are perforated in the form of a bottom plate in the porous electrode plate 40. The discharge holes 42 may have a diameter of about 20 mm, as in the aforementioned porous porous electrode plate, and may be appropriately sensitized within a range of about 1/100 to 100 times as the size of the device increases and decreases. It is not limited by its size.

5 is a comparative table of the energy input efficiency according to the shape of the electrode.

The solid line shows the result of the porous porous electrode plate, the dotted line shows the porous electrode plate, and the dashed-dotted line shows the result of the wire mesh electrode plate. As can be seen, the porous electrode plate has a higher energy input efficiency than the wire mesh electrode plate, and the efficiency of the porous porous electrode plate is higher than that of the wire mesh electrode plate. Therefore, when the combination of the porous porous electrode plate and the porous electrode plate is properly used as in the present invention, higher processing efficiency can be exhibited.

6 is a comparison table of the energy input efficiency according to the distance between the paired electrode plate, each test is the result of the test with only the other conditions are the same and only the distance between the two electrode plate. In the case where the interval is 50 mm, a solid line is shown, the interval is 90 mm, a dashed line, and the interval is 20 mm, and a dashed dashed line is 10 mm. As shown in the diagram, the efficiency of 20 mm rather than 10 mm and 90 mm rather than 20 mm is more efficient. However, the distance does not mean that the efficiency is proportionally higher than 50 mm. It can be seen that when the efficiency is shown to be high. Taken together, the electrode plate spacing was found to be the most efficient near 50 mm. Therefore, in the present invention, the spacing between the porous porous electrode plate and the porous electrode plate is spaced about 50 mm in order to increase the wastewater treatment efficiency.

7 is a waveform diagram of a pulse power source applied to an electrode for confirming instantaneous large power.

In the above-described power supply, the voltage is usually operated within 1 kV, but increases slightly when the resistance is increased while the waste water is purified. Pulse repetition rates can range from a few kHz to hundreds of kHz, but should not exceed 500 kHz, and typically operate within 10 to 100 kHz. The pulse width is suitably within 100 μs, and as short as several μs, the instantaneous large power increases, which is advantageous for the redox reaction. For example, as shown in FIG. 7, in the case of 1.0E-04sec, the voltage peaks at -250V and the current peaks at -35A, so the instantaneous large power output at this time is -250 × -35 = 8750W ≒ 9kW. As such, the device uses several tens of kilowatts of pulsed power to output instantaneous large power of approximately 10 kW (= 7 x 10 ¹⁵ eV) to emit electrons with sufficient energy to remove contaminants in the wastewater. For example, in the case of organic material treatment, about 10 eV is sufficient, so the energy generated by the device can completely remove contaminants that require much higher energy.

For reference, the energy required to remove harmful components is 4.5 eV for H ₂ , the excitation energy for excitation of external electrons to generate radicals is 7 eV, and for O ₂ is 5.1 and 7.9 eV, respectively. And N ₂ are 9.8 and 6.3 eV, respectively. The decomposition energy of CN is 3.17 eV, and 4.04 eV is required for NH.

Now, the effects of the present invention will be described in detail with reference to the above drawings.

In order to treat the wastewater, the controller 80 first opens the supply control valve 62 to introduce the wastewater into the reactor 20 through the injection pipe 60. The water level controller 90 detects the waste water level in the reaction tank 20 and sends a detection signal to the controller 80 when the set height is reached. Then, the control unit 80 closes the open supply control valve 62 to block the supply of waste water. Therefore, the waste water is contained in the reaction tank 20 to an appropriate level, and the porous electrode plate 30 and the porous electrode plate 40 are immersed in the waste water. In this state, the low-voltage high-frequency pulse power is applied from the power supply unit 10 to the porous porous electrode plate 30 and the porous electrode plate 40 to generate underwater discharge. This discharge causes electrolytic redox and / or agglomeration reactions in the wastewater to purify contaminants. At this time, the circulation pump 100 is operated so that the waste water in the reaction tank 20 is circulated evenly. When the purification of the waste water is completed in this way, the controller 80 opens the discharge control valve 72 to discharge the purified water in the reaction tank 20 to the outside through the discharge pipe 70.

As described above, the present invention induces a redox reaction to purify the contaminants in the wastewater. During discharge electrolysis, gases such as hydrogen and oxygen are generated at the same time and water vapor is generated due to the temperature rise by the discharge hot electrons. Therefore, the discharge efficiency can be confirmed through the amount of bubbles (50 μm) generated during the reaction. At this time, the intermediate product generated in real time includes the strong oxidizing power O ·, OH ·, O ₃ , H +, OH −, H ₃ O +, H ₃ O ₂ −, and the main production mechanism is as follows.

Positive electrode (Ti electrode coated with Pt); [Pt (6) + 4e- ↔ Pt (2)]

Oxidation reaction in the positive electrode;

H ₂ O ↔ H + + OH- ↔ H + + OHads. (Radical) + e-

2OH- ↔ H ₂ O + O (radical) + 2e-

O + O ₂ ↔ O ₃ (oxidant)

Negative electrode (Ti electrode); [3 (Ti (3) ↔ Ti (6) + 3e-)]

Reduction reaction at the negative electrode;

H ₂ O ↔ H + + OH-

2H + + 2e- ↔H ₂

As described above, ammonia nitrogen and nitrate nitrogen, which are contaminants in the wastewater, are reacted and purified by the radicals generated in the positive electrode and the negative electrode. In particular, in the low-voltage pulse discharge electrolytic technique of the present invention, the reduction treatment of nitrate nitrogen is very excellent.

2NH ₃ + 6OH- ↔ N ₂ + 6H ₂ O + 6e-

NO _3- + 2H ₂ O + 3e- ↔NO + 4OH-

NO _3- + 4H + + 3e- ↔NO + 2H ₂ O

2N + 2NO ↔2N ₂ + O ₂

The present invention also induces agglutination reaction to agglomerate contaminants in wastewater, which can increase treatment efficiency due to dispersibility by instantaneous power. That is, in the case of applying the DC low voltage, the dispersibility is weak and the processing efficiency is somewhat reduced. However, when the low voltage pulse power is applied as in the present invention, the dispersibility is improved and the efficiency is increased. In addition, the coagulation reaction is usually less than 1 second, that is, short stirring to 10 ^-3 ~ 1sec is required, but in the present invention, by using the circulating pump 100 to quickly agitate wastewater to increase the reactivity.

The embodiments disclosed herein are only presented by selecting the most preferred examples to assist those skilled in the art from the various possible examples, the technical spirit of the present invention is not necessarily limited or limited only by this embodiment, the present invention Various changes and modifications are possible within the scope without departing from the spirit of the invention, as well as other equivalent embodiments.

As described above, in the wastewater treatment apparatus using the underwater discharge of the low voltage pulse according to the present invention, since the electrodes are present in the wastewater, the reaction efficiency is immediately reacted with the pollutant at the instant of the generation of discharge electrons and radicals having a short life cycle. There is an advantage to increase. Furthermore, since instantaneous large power of high frequency with a very short pulse width is applied, sufficient energy required to remove contaminants may be transferred.

In addition, the present invention is operated at a low voltage, so when applied to livestock wastewater having livestock, the electromagnetic wave generation is very insignificant and operates at a repetition rate of more than an audible frequency, so that it can be operated without stressing the livestock and also ensure worker safety. There is an advantage. In addition, it can also be sterilized against microorganisms such as bacteria and Escherichia coli according to underwater discharge.

In addition, coating a catalyst or a photocatalyst on the surface of the electrode can further increase the treatment efficiency, and can suppress the elution of the electrode during the redox reaction.

As described above, the present invention has the effect of outputting a low-voltage high-frequency pulse power supply having instantaneous high power to induce electrolytic redox reaction and / or aggregation reaction of pollutants in the wastewater to quickly and efficiently purify the wastewater. .

Claims (8)

A power supply unit supplying a low voltage high frequency pulse power supply of instantaneous large current; And And a reaction tank provided with electrodes to generate discharge by receiving the high frequency pulse power, and purifying contaminants in the wastewater introduced therein by a redox reaction and / or an aggregation reaction. The reactor includes an inlet pipe for injecting wastewater into the inside and a discharge pipe for discharging the purified water therein to the outside, the inlet pipe having a supply control valve for controlling the inflow of wastewater, and the outlet pipe of the purified water. A wastewater treatment apparatus using an underwater discharge of a low voltage pulse, characterized in that the discharge control valve for controlling the discharge. The wastewater treatment apparatus according to claim 1, wherein the power output from the power supply unit has a low voltage within 1 kV, a high frequency of 10 kHz to 500 kHz, and a pulse width within 100 Hz. The wastewater treatment apparatus according to claim 1, further comprising a circulation pump for circulating the wastewater during the reaction treatment in the reaction tank to allow the pollutants in the wastewater to react evenly. The wastewater treatment apparatus of claim 1, wherein the electrodes are electrode plates paired with a positive electrode and a negative electrode, and an insoluble electrode or an eluting electrode is used as the positive electrode. The underwater discharge of the low voltage pulse according to claim 4, wherein the positive electrode and the negative electrode of the electrodes comprise a combination of homogeneous or heterogeneous electrodes selected from a wire mesh electrode plate, a porous electrode plate, and a porous porous electrode plate. Wastewater treatment device using. The wastewater treatment apparatus according to claim 5, wherein the electrodes are spaced at intervals of about 50 mm. The wastewater treatment apparatus according to claim 5, further comprising a catalyst layer or a photocatalyst layer on the surface of the electrode plate in contact with the wastewater. According to claim 1, wherein the water level controller for detecting the waste water level in the reactor and the water level detection value input from the water level regulator to open and close the supply control valve to the outside until the water level in the reactor reaches a constant height And a control unit for controlling the waste water to be supplied from the waste water treatment apparatus.