KR20000006954A - The industrial wastewater treatment process combined the technique of decomposition by ultrasound/oxidants with the biological treatment technique. - Google Patents

Abstract

PURPOSE: An industrial wastewater treatment process using both an ultrasonic wave/oxidizer and a biological treatment method is provided which effectively decomposes/eliminates various toxic/recalcitrant non-biodegradable compounds contained in the industrial wastewater and purifies the wastewater for prevention of the environmental pollutions. CONSTITUTION: An industrial wastewater treatment process comprises the steps of:pretreating the industrial wastewater; a first treating the pretreated industrial wastewater with ultrasonic waves and oxidizers in a low-frequency ultrasonic wave/oxidizer treatment tank having a 20-50 kHz low-frequency ultrasonic wave generator and an oxidizer sprayer, and a high-frequency ultrasonic wave/oxidizer treatment tank having an at least 100 kHz high-frequency ultrasonic wave generator and an oxidizer sprayer; and a second treating the first treated industrial wastewater biologically in a biological treatment tank having an aeration system.

Description

{The industrial wastewater treatment process combined the technique of decomposition by ultrasound / oxidants with the biological treatment technique.}

The present invention relates to the treatment of industrial wastewater, and more particularly, by effectively decomposing and removing various toxic / non-decomposable compounds contained in wastewater discharged from various industries to purify industrial wastewater, thereby preventing environmental pollution. The present invention relates to a method for treating industrial wastewater and an apparatus for performing the same.

In recent years, the amount of industrial wastewater discharged from various industries has been rapidly increased, and the properties of industrial wastewater are significantly malignant and toxic, and as a result, the pollution of the surrounding environment is intensified. Accordingly, various efforts have been made to effectively treat difficult-decomposable industrial wastewater containing a large amount of such components.

As the technologies used so far to treat industrial wastewater, biological treatment technology and physical / chemical treatment technology are applied. Recently, ozone or hydrogen peroxide treatment technology, ultraviolet treatment technology, electron beam treatment technology, plasma treatment technology and the like are being developed or partially developed and used partially.

First of all, biological treatment technology involves the metabolism of microorganisms in the treatment of dissolved organics, suspended solids, and trace organics or heavy metals in waste water. It is a technology to decompose organic matter by using action or to remove heavy metal by adsorbing to microorganism.

By the way, most industrial wastewaters are very variable in the concentration and flow rate of pollutants, vary in their properties, and have a cyclic aromatic compound (= hardly decomposable organic substance) that exists with various toxic pollutants or is difficult to be decomposed by microorganisms. Because of the large amount of compound), when treated by biological treatment technology, microorganisms are killed or the activity is very low, so the treatment is very difficult or impossible.

Next, the physicochemical treatment technique is a technique of separating and flocculating sedimentation and removal of impurities or contaminants in the wastewater by administering various kinds of flocculants and coagulant aids in the wastewater.

When treating industrial wastewater using this physical / chemical treatment technology, since the pH, temperature, components, etc. of industrial wastewater are very diverse and are hardly aggregated by general flocculating agents and flocculating aids, expensive special flocculant / flocculation aids are used. Must be used. Therefore, the treatment costs are high, and the precipitates are very harmful and difficult to treat or dispose of.

Finally, the basic principles of ozone or hydrogen peroxide treatment technology, ultraviolet ray treatment technology, electron beam treatment technology, plasma treatment technology, etc. are used to directly oxidize or generate oxidizing materials to oxidize and decompose difficult-decomposable toxic substances contained in industrial wastewater. Technology. In the case of treating industrial wastewater using this technique, it is selectively used according to the characteristics of the wastewater, and thus its use is limited, and facility costs and operation costs are high, and some wastewater components have low treatment efficiency. It is confirmed.

Conventional industrial wastewater treatment technologies as described above are not satisfactory in terms of treatment efficiency or economics of industrial wastewater. Therefore, there is a need to develop a new industrial wastewater treatment technology that can more effectively treat difficult-to-decomposable industrial wastewater.

The present invention has been made to solve the above-mentioned conventional problems, the first object of the present invention, among the industrial wastewater components discharged from various industries, in particular removed by biological wastewater treatment technology or physical / chemical treatment technology Treatment of industrial wastewater that can decompose various hardly decomposable compounds using ultrasonic energy and oxidizing ozone, hydrogen peroxide or oxygen and completely decompose by metabolic action of microorganisms in biological treatment tank to prevent water pollution. To provide a way.

In addition, the second object of the present invention is to effectively decompose and remove various toxic / hardly decomposable compounds contained in industrial wastewater to purify the wastewater. It is to provide a relatively inexpensive, non-degradable industrial wastewater treatment apparatus.

1 is a view schematically showing the configuration of an industrial wastewater treatment process for performing a process of treatment of difficult-decomposable industrial wastewater in accordance with a preferred embodiment of the present invention; and

Figures 2 to 4 are graphs showing the decomposition of the dye wastewater of Lanacet yellow 4GN, Lanacet yellow 2R, Lanacet orange RN, Lumacron rubine 2GFL, Lumacron NAVY EXN-SF 3001, Lanacet blue 2R and TSS 222.5mg / L admit.

In addition, Figure 5 compares the chromaticity of the dyeing wastewater and the chromaticity after decomposing the dye by irradiating the dyeing wastewater with ultrasonic waves for 6 hours,

FIG. 6 shows five persons including J. Berlan, F. Trabelsi, H. Delmas, AM Wilhelm, and JF Petrignani, who measured the decomposition rate of phenol by irradiating ultrasonic waves at two frequencies of 20 kHz and 541 kHz, which are high frequencies (" Oxidative degradation of phenol in aqueous media using Ultraound ", Ultrasonic Sonochemistry, 1, 2, S97-S102 (1994)) and the results of this study. Is the result of measuring.

<Explanation of symbols for the main parts of the drawings>

20: wastewater storage tank 20P: wastewater supply pump

22: flow meter 30: low frequency ultrasonic wave / oxidant treatment tank

31: cold water jacket 32a: thermocouple

32b: temperature controller 32c: flow control valve

33: pH meta 34: low frequency ultrasonic wave generator

35: wastewater supply pipe 36a: low frequency ultrasonic wave / oxidant treatment tank

Treated water discharge pipe

36b: low frequency ultrasonic wave / oxidizer treatment tank 36c: high frequency ultrasonic wave / oxidizer treatment tank

Treated water sampling pipe bypass pipe

37: low frequency ultrasonic wave / oxidant treatment tank 38a: cooling water supply pipe

Drain pipe

38b: cooling water discharge pipe 39a: oxidant (ozone, etc.) supply pipe

39b: oxidant (ozone, etc.) dispersion tube 40: high frequency ultrasonic wave / oxidant treatment tank

41: coolant jacket 42a: thermocouple

42b: temperature controller 42c: flow control valve

43: pH meta 44: high frequency ultrasonic wave generator

45: high frequency ultrasonic wave / oxidant treatment tank 46a: high frequency ultrasonic wave / oxidant treatment tank

Supply pipe Treatment water discharge pipe

46b: high frequency ultrasonic wave / oxidizer treatment tank 47: high frequency ultrasonic wave / oxidizer treatment tank

Treated water sampling pipe Drain pipe

48a: cooling water supply pipe 48b: cooling water discharge pipe

49a: oxidant (ozone, etc.) supply pipe 49b: oxidant (ozone, etc.) dispersion pipe

40P: high frequency ultrasonic wave / oxidizer treatment tank 40R: high frequency ultrasonic wave / oxidizer treatment tank

Treated water return pump Treated water return pipe

50: biological treatment tank 54: aeration period

55: high frequency ultrasonic wave / oxidizer treatment tank 56a: biological treatment tank treatment water outflow

Treated water supply pipe

56b: biological treatment tank treated water 57: sediment sludge discharge pipe

Sample collector tube.

50R: biological treatment tank treated water 50P: biological treatment tank treated water returned

Return pipe pump

In order to achieve the first object described above, the present invention,

Decomposing the industrial wastewater (S1);

The industrial wastewater, which has undergone pretreatment, is introduced into a low-frequency ultrasonic wave / oxidant treatment tank in the range of 20 to 50 kHz equipped with an ultrasonic generator and an oxidizer dispersing device to irradiate ultrasonic waves and, if necessary, to increase the decomposition efficiency of hardly decomposable components. While injecting oxidants such as ozone and hydrogen peroxide, first decompose the components decomposed by low frequency ultrasonic waves such as benzene,

In the case of wastewater containing a large amount of components that are not easily decomposed by low frequency ultrasonic waves such as phenol and amine, the treated water which has been processed in the low frequency ultrasonic / oxidant treatment tank is introduced into the high frequency ultrasonic wave / oxidant of 100 kHz or higher again. Irradiating the ultrasonic wave and injecting an oxidizing agent if necessary to further increase the decomposition rate of the hardly decomposable compound (S1); And

It is intended to provide a method for treating industrial wastewater including a secondary treatment step (S2) of introducing wastewater treated in a first treatment step into a biological treatment tank equipped with aeration machine to completely purify decomposed hardly decomposable compounds.

In addition, the present invention, in order to achieve the second object of the present invention,

Wastewater reservoir for temporarily storing pretreated industrial wastewater;

A cooling water jacket is mounted on the outer wall, and a thermocouple, pH meta, a low frequency ultrasonic wave generator, and an oxidant dispersion plate are installed therein, and a low frequency ultrasonic wave / oxidant treatment tank for primarily decomposing the industrial wastewater supplied from the waste water storage tank;

A high frequency ultrasonic / oxidant treatment tank in which a thermocouple, pH meta, and an oxidant dispersion plate are installed inside, such as a low frequency ultrasonic wave / oxidant treatment tank, but an ultrasonic wave generator is installed for a high frequency of 100 kHz or more;

Aeration is installed inside, and is sufficiently decomposed and discharged enough to enable biological treatment in low frequency ultrasonic / oxidant treatment tanks, or sufficient to enable biological treatment of components that are not sufficiently decomposed enough for biological treatment in low frequency ultrasonic / oxidant treatment tanks. A biological treatment tank for secondly purifying the primary decomposed industrial wastewater discharged from the high frequency ultrasonic wave / oxidant treatment tank which is decomposed easily; And

It provides an apparatus for treating industrial wastewater comprising the wastewater storage tank, the two low frequency and high frequency ultrasonic wave / oxidant treatment tanks, and fluid connection means extending between the biological treatment tanks.

According to the industrial wastewater treatment process according to the present invention as described above, the decomposition efficiency of the hardly decomposable components is investigated while irradiating the non-degradable wastewater discharged from various industries in each of the two low frequency and high frequency ultrasonic wave / oxidant treatment tanks. To further increase, if necessary, ozone, hydrogen peroxide or oxygen is sprayed as an oxidation aid to primarily decompose and remove various hardly decomposable compounds contained in the waste water. Next, the first industrially decomposed wastewater is completely purified in a biological treatment tank, thereby effectively purifying various hardly decomposable harmful compounds contained in the industrial wastewater.

Hereinafter, with reference to the accompanying drawings will be described in detail the configuration and treatment process of the industrial wastewater treatment apparatus according to a preferred embodiment of the present invention.

First, Figure 1 is a schematic diagram showing the configuration of an apparatus for performing the industrial wastewater treatment process according to a preferred embodiment of the present invention.

Referring to FIG. 1, the industrial wastewater treatment process is a low frequency ultrasonic wave / oxidant treatment for primarily decomposing wastewater supplied from a wastewater storage tank 20 and a wastewater storage tank 20 for temporarily storing pretreated water. The tank 30 and the high frequency ultrasonic wave / oxidation tank treatment tank 40, and the biological treatment tank 50 for the secondary complete purification treatment of the firstly decomposed wastewater.

The wastewater storage tank 20 and the low frequency ultrasonic wave / oxidant treatment tank 30 are connected to the wastewater supply pipe 35, and the wastewater supply pipe 35 is provided with a wastewater supply pump 20P and a flow meter 22.

The wastewater supply pump 20P forces the wastewater discharged from the wastewater storage tank 20 to the low frequency ultrasonic wave / oxidant treatment tank 30 at a constant pressure. The flowmeter 22 is for measuring the amount of wastewater supplied into the low frequency ultrasonic wave / oxidant treatment tank 30 through the wastewater supply pipe 35.

Cooling water jacket 31 is provided on the outer wall of the low frequency ultrasonic wave / oxidizer treatment tank 30. One side of the cooling water jacket 31 is connected to a cooling water inlet pipe 38a extending from an external cooling water source, and the other side of the cooling water jacket 31 is connected to a cooling water discharge pipe 38b. The flow rate control valve 32c is installed in the coolant inflow pipe 38a. The flow rate control valve 32c is electrically connected to a temperature controller 32b connected to a K-type thermocouple 32a installed by being inserted into the low frequency ultrasonic wave / oxidant treatment tank 30. The thermocouple 32a, the temperature controller 32b, and the flow rate control valve 32c adjust the supply amount of the coolant supplied to the coolant jacket 31 according to the temperature change of the wastewater treated in the low frequency ultrasonic wave / oxidant treatment tank 30. By automatically adjusting, ultimately, the temperature of the wastewater treated in the low frequency ultrasonic wave / oxidant treatment tank 30 is constantly controlled.

In the low frequency ultrasonic wave / oxidant treatment tank 30, a pH meta 33 and a low ultrasonic wave generator 34 are also provided. pH meta (33) is optimized by measuring the pH at regular intervals during the irradiation of the ultrasonic wave because the pH changes depending on the composition of the waste water when the ultrasonic wave is irradiated to the wastewater contained in the low-frequency ultrasonic wave / oxidant treatment tank (30) To maintain the reaction state of. The low frequency ultrasonic wave generator 34 is capable of irradiating low frequency ultrasonic waves having a frequency in the range of 20 to 50 kHz into the wastewater. Preferably, a piezoelectric transducer (PZT) is used. The low frequency ultrasonic wave generator 33 can use either a contact type that directly immerses a "horn" in the waste water and an indirect contact type that attaches it to the bottom or wall of the wastewater treatment tank, but it can be repaired or replaced. It is preferable to configure the submersible submersible in the treatment tank (30).

The direct contact type is a probe type that directly immerses the "horn" with a titanium tip attached to the wastewater, which is a medium for delivering low frequency ultrasonic waves, and the indirect contact type "horn" to the bottom of the low frequency ultrasonic / oxidant treatment tank 30. It is attached cleaning bath type.

An oxidant dispersing pipe 39b is provided between the inner wall of the low frequency ultrasonic wave / oxidizer treatment tank 30 and the low frequency ultrasonic wave generator 34. This oxidant dispersing tube 39b is composed of a circular tube with a small hole or a separate dispersing apparatus. The oxidant dispersion pipe 39b sprays ozone, hydrogen peroxide or oxygen into the wastewater in the low frequency ultrasonic / oxidant treatment tank 30 as an oxidizing aid if necessary in order to improve the decomposition efficiency of the hardly decomposable compound contained in the wastewater. The treatment water discharge pipe 36a is installed below the wall of the low frequency ultrasonic wave / oxidizer treatment tank 30 and the drain pipe 37 is installed at the bottom.

Just above the bottom of the low frequency ultrasonic / oxidant treatment tank 30, the low frequency ultrasonic / oxidant treatment tank discharge pipe 36a extends downward toward the high frequency ultrasonic / oxidant treatment tank 40, and at the end thereof, the high frequency ultrasonic / oxidant treatment tank supply pipe 45 One side of) is connected. At this time, the treated water of the low frequency ultrasonic / oxidant treatment tank 30 supplied to the high frequency ultrasonic / oxidizer treatment tank 40 through the low frequency ultrasonic / oxidant treatment tank discharge pipe 36a and the high frequency ultrasonic / oxidant treatment tank supply pipe 45 is gravity. The high frequency ultrasonic wave / oxidant treatment tank 40 is placed below the low frequency ultrasonic wave / oxidizer treatment tank 30 so as to be transported by.

However, if the waste capacity is large, the low frequency ultrasonic wave / oxidant treatment tank 30 and the high frequency ultrasonic wave / oxidant treatment tank 40 can be placed on the same height, and in this case, the low frequency ultrasonic wave / oxidant treatment tank discharge pipe. (36a) or a low frequency ultrasonic / oxidizer treatment tank supply water supply pump is installed in the high frequency ultrasonic wave / oxidizer treatment tank supply pipe 45, and the high frequency ultrasonic wave / oxidizer treatment tank is treated at a constant pressure by the pump. To be supplied). Also

One end of the high frequency ultrasonic wave / oxidant treatment tank bypass pipe 36c is connected to the middle one point of the low frequency ultrasonic wave / oxidizer treatment tank discharge pipe 36a. This is because most of the components of the wastewater are decomposed to a degree that can be purified in the biological treatment tank 50 by low frequency ultrasonic waves / oxidants such as benzene. It is to be sent directly to the biological treatment tank 50 which is lower than the high frequency ultrasonic / oxidant treatment tank by gravity through the high frequency ultrasonic / oxidant treatment tank bypass tube 36c without being sent to the treatment tank 40. .

The structure of the high frequency ultrasonic wave / oxidant treatment tank 40 is the same as that of the low frequency ultrasonic wave / oxidizer treatment tank 30. That is, the coolant jacket 41 is installed on the outer wall of the high frequency ultrasonic wave / oxidizer treatment tank 40. One side of the cooling water jacket 41 is connected with a cooling water inlet tube 48a extending from an external cooling water source, and the other side of the cooling water jacket 41 is connected with a cooling water discharge pipe 48b. The flow rate control valve 42c is installed in the cooling water inlet pipe 48a. The flow rate control valve 42c is electrically connected to a temperature controller 42b connected to a K-type thermocouple 42a installed by being inserted into the high frequency ultrasonic wave / oxidizer treatment tank 40. The thermocouple 42a, the temperature controller 42b, and the flow rate control valve 42c adjust the supply amount of the coolant supplied to the coolant jacket 41 according to the temperature change of the wastewater treated in the high frequency ultrasonic wave / oxidant treatment tank 40. By automatically adjusting, ultimately, the temperature of the wastewater treated in the high frequency ultrasonic wave / oxidant treatment tank 30 is constantly controlled.

In the high frequency ultrasonic wave / oxidizer treatment tank 40, a pH meta 43 and a high ultrasonic wave generator 44 are also provided. pH meta (43) is optimized by measuring the pH at regular intervals during the irradiation of the ultrasonic wave because the pH changes depending on the composition of the waste water when the ultrasonic wave is irradiated to the wastewater contained in the high-frequency ultrasonic wave / oxidant treatment tank (40). It is to maintain the pH value to become the reaction state of. The high frequency ultrasonic wave generator 44 is capable of irradiating high frequency ultrasonic waves with a frequency of 100 kHz or more into the wastewater. Preferably, a piezoelectric transducer (PZT) is used. The high frequency ultrasonic wave generator 43 can use either a contact type that directly immerses a "horn" in the waste water and an indirect contact type that attaches it to the bottom or wall of the wastewater treatment tank, but it can be repaired or replaced. It is preferable to configure the submersible submersible in the oxidant treatment tank (40).

One end of the high frequency ultrasonic wave / oxidant treatment tank 40R is connected to one point of the high frequency ultrasonic wave / oxidant discharge tube 46a, and the other end thereof is connected to the low frequency ultrasonic wave / oxidant treatment tank 30. A conveying pump 40P is provided in the high frequency ultrasonic wave / oxidizer treatment tank treated water conveying pipe 40R. This is to recirculate some or all of the treated water decomposed in the high frequency ultrasonic wave / oxidant treatment tank 40 to the low frequency ultrasonic wave / oxidant treatment tank 30 at a constant pressure in order to further increase the decomposition rate in the first treatment step S1. It is for.

The high frequency ultrasonic / oxidant treatment tank discharge pipe 46a is connected to the outside under the wall of the high frequency ultrasonic wave / oxidant treatment tank 40, and the biological treatment tank supply pipe 55 is connected to the end thereof. At this time, the biological treatment tank 50 is located at a lower position than the high frequency ultrasonic wave / oxidant treatment tank 40, and the treated water treated in the high frequency ultrasonic wave / oxidant treatment tank 40 is removed from the high frequency ultrasonic wave / oxidizer treatment tank 40 by gravity. The biological treatment tank 50 is transferred to. However, when the amount of waste water is high, the low frequency ultrasonic / oxidant treatment tank 30 and the high frequency ultrasonic / oxidant treatment tank 40 are placed on the same height, so that the biological treatment tank 50 is also placed on the same side of them. The primary treatment water supply pump is installed in the ultrasonic / oxidant treatment tank discharge pipe 46a.

The aeration machine is installed in the biological treatment tank 50, and the sludge discharge pipe 57 for discharging the sludge is extended to the bottom of the biological treatment tank 50. In addition, one side of the biological treatment tank 50, the treated water outlet pipe 56a is extended to the outside. One of the treated water conveyance pipe 50R is connected to the middle of the biological treatment tank treated water outlet pipe 56a, and the other of the treated water conveying pipe 50R extends into the wastewater storage tank 20. The middle one point of the treated water conveying pipe 50R is provided with a biological treatment tank treated water conveying pump 50P for forcibly circulating part or all of the treated water to the wastewater storage tank 20 in accordance with the treatment rate in the final treated water. In addition, a sampling pipe 56b of the treated water of the biological treatment tank 50 is connected to another middle point of the final treated water outlet pipe 56a.

In order to treat industrial wastewater using the primary treatment step (S1) configured as described above is subjected to the following process.

First, pretreatment is performed to separate solid components through methods such as filtration, sedimentation or flotation separation of wastewater from dyeing factories, agrochemical plants, pharmaceutical factories, oil refineries, food plants, and soap and detergent plants discharged from various chemical processes. do. The wastewater undergoing the pretreatment process is introduced into the wastewater storage tank 20, and is subsequently supplied into the low frequency ultrasonic wave / oxidant treatment tank 30 through the wastewater supply pipe 35 of the low frequency ultrasonic wave / oxidant treatment tank 30.

When the industrial wastewater is supplied into the low frequency ultrasonic wave / oxidant treatment tank 30, the operator of the industrial wastewater treatment process turns on the power switch (not shown) of the low frequency ultrasonic wave generator 34 to generate ultrasonic waves. When the generated ultrasonic waves are irradiated into the wastewater, the oxidant dispersion plate 39b is operated by supplying the oxidant through the oxidant supply pipe 39a to further increase the decomposition rate of the hardly decomposable components contained in the wastewater. Oxidant is injected into the wastewater. At this time, ozone, hydrogen peroxide or oxygen may be used as the oxidizing agent, and ozone is preferably used.

When ultrasonic waves are irradiated with wastewater, cavitational bubbles are generated and they burst and generate high-temperature and high-pressure energy, and water molecules decompose and generate radicals. Most of the hardly decomposable compounds contained in the waste water are decomposed by pyrolysis by this high temperature and high pressure energy or by breaking of the ring structure by reaction with radicals.

The temperature of the wastewater is increased by the energy of high temperature and high pressure generated when ultrasonic waves are irradiated to the wastewater, which is the amount of cooling water flowing into the cold water jacket 31 attached to the outer wall of the low frequency ultrasonic wave / oxidizer treatment tank 30. By controlling the reaction heat of reaction generated during the decomposition reaction of the compound is removed. As a result, the low frequency ultrasonic wave / oxidant treatment tank 30 is maintained at the temperature at which the decomposition efficiency of the hardly decomposable compound is the best. Alternatively, the same effect can be obtained by changing the structure of the low frequency ultrasonic wave / oxidizer treatment tank 30 without providing the cooling water jacket 31.

The treated water once the compounds which are easily decomposed by low frequency ultrasonic waves such as TCE and benzene in the low frequency ultrasonic / oxidant treatment tank 30 is treated with components that are not easily decomposed by low frequency ultrasonic waves such as phenols and amines. Of the low frequency ultrasonic / oxidant treatment tank discharge pipe 36a and the low frequency ultrasonic / oxidant treatment tank discharge pipe 36a connected to the high frequency ultrasonic / oxidant treatment tank from below the wall of the low frequency ultrasonic / oxidant treatment tank 30 for decomposition. It is conveyed by gravity into the high frequency ultrasonic wave / oxidizer treatment tank 40 through the high frequency ultrasonic wave / oxidizer treatment tank supply pipe 45 connected to the lower end. At this time,

A part of the treated wastewater was sampled through the low frequency ultrasonic wave / oxidant treatment tank treated water sample pipe 36b installed at one point in the middle of the low frequency ultrasonic wave / oxidant treatment tank discharge water 36a, and the resolution was measured. Depending on the output of the ultrasonic wave, whether to use an oxidizing agent, preferably ozone, its injection amount and processing time, and whether or not to bypass the high-frequency ultrasonic / oxidant treatment tank 40, Determine a pass amount;

If most of the components of industrial wastewater are easily decomposed by low frequency ultrasonic waves, such as TEC and benzene, the low frequency ultrasonic wave / oxidant treatment tank is treated with a low frequency ultrasonic wave / oxidant treatment tank treatment water discharge pipe 36a and a high frequency ultrasonic wave / oxidizer treatment. One point between the tank supply pipes 45 is transferred to the biological treatment tank through the high frequency ultrasonic wave / oxidant treatment tank bypass pipe 36c connected to the biological treatment tank below.

The treated water of the low frequency ultrasonic / oxidant treatment tank 30 supplied into the high frequency ultrasonic wave / oxidant treatment tank 40 is subjected to the same procedure as when the industrial wastewater pretreated beforehand was treated in the low frequency ultrasonic / oxidant treatment tank 30. After the decomposition treatment, the biological treatment is performed through the high frequency ultrasonic wave / oxidizer treatment tank discharge water 46a and the biological treatment tank supply pipe 55 extending from the high frequency ultrasonic wave / oxidizer treatment tank 40 toward the biological treatment tank 50. It is conveyed into the processing tank 50. At this time,

A part of the treated wastewater was sampled through a high frequency ultrasonic wave / oxidizer treatment tank treated water sampling tube 46b connected to one center of the treated water discharge tube 46a of the high frequency ultrasonic wave / oxidant treatment tank, and the decomposition degree was measured. According to the control of the output of the ultrasonic wave, and whether or not to use the oxidizing agent, preferably ozone, and the treatment time, and the high frequency ultrasonic wave / oxidant treatment tank low-frequency ultrasonic wave / oxidant treatment tank (30) Determine whether or not to return).

The decomposed treated water supplied into the biological treatment tank 50 is completely purified for 8 to 24 hours depending on the characteristics of the wastewater, and finally discharged to the outside through the biological treatment tank treated water outlet pipe 56, and the biological treated tank effluent is As a result of analyzing the sample collected from the sampling tube 56b, if the residual compound contains more than the allowable amount, the holding time in the biological treatment tank is adjusted according to the degree, and some of the treated water is returned to the biological treatment tank treatment water return pump. By 50P, part or all of the effluent of the biological treatment tank 50 is refluxed to the wastewater storage tank 20 through the biological treatment tank treated water return pipe 50R. this is,

This is to further increase the overall treatment rate of the wastewater if the quality of the wastewater treated through the two low frequency and high frequency ultrasonic / oxidation tanks and biological treatment tanks is not satisfactory.

Results and Discussion

In fact, only ultrasonic waves are irradiated with aqueous solutions of three substances, trichloroethylene (TCE), benzene, and 2,4-dichlorophenol (2,4-DCP), which are commonly contained in industrial wastewater discharged from chemical plants. And ultrasonic waves were irradiated under the same conditions as when only ultrasonic waves were irradiated with a sound intensity of 0.12 Watt / mL (output: 600 Watts) and 0.08 Watt / mL (output: 400 Watts) in a washing mold having a frequency of 28 kHz. Decomposition rate (%) for the TCE and benzene when the ozone is injected together while the results are shown in Table 1 below.

The results shown in Table 1 were obtained through the following experimental method. In other words, the effect of the concentration is that the experimental aqueous solution was added to the flask on the day of the experiment, distilled water sufficiently saturated with air, the sample material (reagent stock solution) was added, the pH was adjusted to 7 by adding HClO ₄ and NaOH, and then 150 ML was taken and the ultrasonic wave was irradiated for 120 minutes in a 20 kHz, 700 W welder-type reactor in which the reaction temperature was maintained at 20 ° C., and an analysis sample was taken every 10 minutes for analysis.

The initial pH of the aqueous solution was adjusted to 1,000 ppm of the aqueous solution of the three sample materials and adjusted to each experimental pH value. The experiment and measurement method were the same as in the experiment for measuring the effect of the initial concentration of the aqueous solution. It was.

The reaction temperature was determined by considering the lowest boiling point (80.1 ℃) of benzene among the three sample materials. The concentration and pH of the aqueous solution of each of the three sample materials were set to 1,000 ppm and pH 7, respectively. The experiment was carried out in the same manner as in the experiment for measuring the effect of the initial concentration of.

Influence on the frequency and sound intensity was measured by measuring the concentration and pH of the sample solution at 500ppm and pH7, respectively, and the reactor used two types of washing tanks, 28 kHz and 40 kHz, and 500 ml of the sample. Into a 500 ml glass beaker filled with 4,500 ml of water as an ultrasonic delivery medium in the reaction vessel, and the ultrasonic wave was placed in the beaker containing the sample solution in the water. This is because the ultrasonic effect is almost the same as when the ultrasonic wave is almost penetrated into the glass wall, and the ultrasonic effect is almost the same as when the ultrasonic wave is directly irradiated on the sample liquid. . The effects of frequency were tested in two frequency reactors, and the sound intensity and effects were summarized for each of the three outputs to compare the effects of frequency. The experiment and analysis method were the same as in the case of the experiment for measuring the influence of the initial concentration of the aqueous solution.

The effect of ozone is the ozone generated from the corona discharge ozone generator for two outputs of 600 Watt (sound intensity: 0.12 W / mL) and 400 Watt (sound intensity: 0.02 W / mL) in a 28 kHz reactor. It was measured by injecting 0.8 ~ 0.9 mg per 1L.

The concentration of each influencer was analyzed by GC (Gas Chromatography) immediately after taking the analytical sample from the sampling container.In case of unavoidable, the collected sample was put in a glass vial and kept in a cool place until it was completely sealed and analyzed. Analyzed. At this time, GC is a product of Varian (Model 3400) of the United States and the product of Young Young Science (Model 600D) of Korea, the detector is FID and TCD, and the capillary column (capilary column) was used. However, three capillary columns were used because all three materials were not analyzed in one column.

In Figures 2 to 4, the dye components include Lanacet yellow 4GN, Lanacet yellow 2R, Lanacet orange RN, Lumacron rubine 2GFL, Lumacron NAVY EXN-SF 3001, Lanacet blue 2R and the like. Is shown.

The results shown in FIGS. 2 to 4 show that the dyeing wastewater using the washing tank-type ultrasonic generator 38 in the ultrasonic / oxidizer treatment tank 30 maintained at a frequency of 40 kHz, a sound intensity of 0.12 W / ml, and a sludge temperature of 20 ° C. After the sample was irradiated with ultrasonic waves for a predetermined time (0, 60, 90 minutes), an appropriate amount of sludge discharged from the sedimentation tank of the terminal sewage treatment plant in Cheongju-si was injected and the ultrasonic wave was measured by measuring the reduced oil of dissolved oxygen. In these three cases, the dissolved oxygen consumption rate is shown in Table 2 below.

The measurement results shown in Table 2 below show that as the ultrasonic irradiation time increases, the consumption rate of dissolved oxygen increases. This indicates that the hardly decomposable compound contained in the waste water was decomposed to a large extent by ultrasonic waves.

On the other hand, the reason for measuring the rate of dissolved oxygen reduction by microorganisms as an indicator of elimination of toxic or hardly degradable organic matter is that when the toxic or hardly decomposable organic material is decomposed, its original characteristics are lost, the toxicity is lost or weakened, and the microorganisms are ingestible. It is based on the fact that oxygen intake increases as the activity becomes more active. Therefore, if excess oxygen is injected into the wastewater irradiated with ultrasonic waves for a certain time and the dissolved oxygen dissolved in the wastewater is measured for a predetermined time, the dissolved oxygen is reduced, and the hardly decomposable organic matter contained in the wastewater is decomposed. .

In addition, Figure 5 shows that the original dark blue color changes to almost yellow when irradiated with ultrasound for 6 hours in the same sample (left beaker of the photo) under the same conditions as when the results shown in FIGS. 2 to 4 were obtained. (Right beaker). This is because when the benzene nucleus, which is a basic component of the hardly decomposable compounds, is decomposed by ultrasonic irradiation, as shown in the reaction mechanism shown below, the wastenol produced as an intermediate product is white, but when the purity falls, it is pink or red, and catechol is water. When dissolved in brown, hydroquinone is or white and quinone is yellow, demonstrating that the benzene ring of the fuel has been largely degraded as such an intermediate by ultrasonic irradiation.

Ultrasonic irradiation of the hardly decomposable compounds takes a very long time until the final product is converted into H ₂ , H ₂ O, and CO ₂ . Rather than irradiating ultrasound, it is more economical to use microbial treatment from then on until complete treatment.

The results of predicting the ultrasonic decomposition mechanism of benzene and trichloroethylene (TCE), which are the simplest among the hardly decomposable aromatic compounds, are as shown in the diagram below.

For reference, even in the case of a hardly decomposable compound composed of several benzene nuclei or having a cyclic structure, the decomposition reaction mechanism of the benzene nucleus or ring structure must be broken, and therefore, the decomposition reaction mechanism is also considered to be in accordance with this mechanism.

Mechanism of Decomposition of Benzene

Decomposition Mechanism of TCE

The ultrasonic decomposition reaction in TCE aqueous solution is pyrolysis reaction and thus radical reaction, the possible reaction route is

①. TCE receives ultrasonic energy and changes to unsaturated chlorinated hydrocarbon radicals, and then releases one chlorine radical, or receives one chlorine radical from chlorine molecules produced by recombination of two chlorine radicals, and two unsaturated hydrocarbon chloride radicals bind to each other. To other unsaturated hydrocarbons,

②. These become unsaturated hydrocarbons by dechlorination reaction,

③. By hydrogenation, unsaturated hydrocarbons become saturated hydrocarbons,

④. The saturated hydrocarbon may be thermally decomposed or oxidized by HO ₂ radicals, O ₃ , H ₂ O _2, etc. generated during the ultrasonic decomposition reaction of water molecules to be decomposed into final products CO ₂ and H ₂ O. It seems to be.

This is shown schematically as follows.

6 shows J. Berlan, F. Trabelsi, H. Delmas, AM Wilhelm, and JF Petrignani, which measured the decomposition rate of phenol by separately irradiating two ultrasonic waves of low frequency 20 kHz and high frequency 541 kHz, respectively. Experimental results ("Oxidative degradation of phenol in aqueous media using ultraound", Ultrasonic Sonochemistry, 1, 2, S97-S102 (1994)) and the researchers found that the output of phenol in a welder type ultrasonic reactor with a frequency of 20 kHz was 700 Watt. The result of measuring the decomposition rate is shown. In FIG. 6, the result of J. Berlan et al. Shows that phenol solution is hardly decomposed until 2 hours after 20 kHz ultrasonic irradiation. In the case of 541 kHz ultrasound, almost all decomposition is performed for 100 minutes. In the case of 20 kHz ultrasound, the dissipation tendency was almost similar to the results of our experiments, which showed that 4 to 6% of the disintegration tended to occur during the same period of time when irradiated with a frequency of 20 kHz and an output of 700 watts.

Therefore, the results of this experiment prove that it is effective to irradiate low frequency and high frequency ultrasonic waves together to treat industrial wastewater containing hardly decomposable compounds to the extent that it does not cause environmental pollution by ultrasonic irradiation.

According to the treatment process of the industrial wastewater according to the present invention as described above, by introducing ultrasonic wastewater discharged from various industries into the ultrasonic / oxidant treatment tank 30 and irradiating ultrasonic waves, ozone, hydrogen peroxide or oxygen as needed as an oxidation aid Spraying decomposes and removes various compounds contained in the wastewater. Thus, by treating the wastewater that has been primarily purified in the ultrasonic / oxidant treatment tank 30 with the biological treatment tank 40, the treatment of various industrial wastewater that is not effectively treated by conventional wastewater treatment technology is completed. It is possible.

That is, the industrial wastewater treatment process according to the present invention can effectively decompose and remove various toxic / hardly decomposable compounds which are not removed by existing biological wastewater treatment technology or physical / chemical treatment technology among industrial wastewater components. In particular, in the case of adding ozone, hydrogen peroxide or oxygen as an oxidizing agent, the treatment efficiency can be further increased.

In addition, in the conventional physicochemical treatment process, a large amount of sludge is generated due to agglomeration, so that the cost of sludge treatment is considerably higher among the wastewater treatment costs, but the generation of sludge according to the industrial wastewater treatment method according to the present invention can be greatly reduced. It is economical in terms of processing cost.

In addition, since the structure of the apparatus used to perform the industrial wastewater treatment method according to the present invention is not only simple, but also domestic production is possible, the apparatus cost and operation cost are low.

Although described above with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified and changed within the scope of the invention without departing from the spirit and scope of the invention described in the claims below I can understand that you can.

Claims (10)

Pretreatment of the industrial wastewater (S1); The industrial wastewater from the pretreatment stage is continuously fed into a low frequency ultrasonic / oxidant treatment tank equipped with a low frequency ultrasonic generator of 20 to 50 kHz and an oxidizer dispersing unit, and a high frequency ultrasonic generator / oxidant treating tank equipped with a high frequency ultrasonic generator of 100 kHz and an oxidant dispersing apparatus. Introducing and irradiating ultrasonic waves and injecting an oxidizing agent to perform primary treatment (S2); And The industrial wastewater treatment process comprising the step (S3) of introducing the first treated industrial wastewater into a biological treatment tank equipped with aeration machine (S3). According to claim 1, wherein in step (S2), the temperature regulator electrically connected to the thermocouple installed in each of the two low frequency and high frequency ultrasonic wave / oxidant treatment tank, and a cooling water jacket installed on the outer wall of the ultrasonic / oxidant treatment tank In each of the two low frequency and high frequency ultrasonic / oxidant treatment tanks by adjusting the amount of cooling water supplied to the cooling water jacket by operation of a flow control valve connected to the temperature controller and electrically connected to the temperature controller. Industrial wastewater, characterized in that to control the temperature of the industrial wastewater to be treated in, and to measure the pH of the industrial wastewater using the pH meta installed in each of the two low frequency and high frequency ultrasonic wave / oxidant treatment tanks Treatment method. The low frequency ultrasonic / oxidant treatment tank is connected to one end of the high frequency ultrasonic / oxidant treatment tank bypass tube, and the wastewater is composed of most biological treatment tanks in the low frequency ultrasonic / oxidant treatment tank such as benzene. In the case of those that are decomposed to the extent that can be purified in (50), the high-frequency ultrasonic wave / oxidant treatment tank bypass tube without sending the treated water decomposed in the low frequency ultrasonic wave / oxidant treatment tank 40 to the high frequency ultrasonic wave / oxidant treatment tank ( 36c) directly to the biological treatment tank (50). In claim 1, one end of the high frequency ultrasonic wave / oxidizer treatment tank return water pipe is connected to one point between the high frequency ultrasonic wave / oxidizer discharge tube and the low frequency ultrasonic wave / oxidizer treatment tank, and the other end is connected to the low frequency ultrasonic wave / oxidizer treatment tank. Ultrasonic / oxidant treatment tank A part or all of the treated water is returned to the low frequency ultrasonic / oxidant treatment tank to be decomposed in the low frequency ultrasonic / oxidant treatment tank to repeat the decomposition treatment process to further increase the overall throughput. The method of claim 1, wherein one end of the treated water return pipe is connected to the middle of the final treated water discharge pipe connected to one side of the biological treatment tank 50, and the other side of the treated water return pipe is connected to the wastewater storage tank. Part or all of the final purified treatment water is returned to the wastewater reservoir to further increase the overall treatment efficiency of the wastewater. According to claim 2, wherein a portion of the treated water in each treatment tank using a sampling tube installed in the middle of the discharge tube of the low frequency ultrasonic wave / oxidant treatment tank and the discharge tube of the high frequency ultrasonic wave / oxidant treatment tank. Collecting a sample to measure the decomposition rate and according to the results of the industrial wastewater, characterized in that the output of the ultrasonic wave irradiated from the ultrasonic generator, the supply amount of the oxidant injected from the oxidant dispersing device, and the return or reflux amount is adjusted Treatment method. The method for treating industrial wastewater according to any one of claims 1 to 6, wherein the oxidizing agent is made of ozone, hydrogen peroxide or oxygen. Wastewater storage for temporarily storing pretreated industrial wastewater; Cooling water jacket is mounted on the outer wall, and thermocouple, pH meta, ultrasonic generator and oxidant dispersing pipe are installed inside, and two low frequency and high frequency ultrasonic wave / for primary purification of industrial wastewater supplied from the wastewater storage tank Oxidant treatment tank; A biological treatment tank having an aerator installed therein for secondary purification of the first purified industrial wastewater discharged from the two low frequency and high frequency ultrasonic wave / oxidant treatment tanks; And And a fluid connection means extending between said wastewater reservoir, said low frequency and high frequency ultrasonic wave / oxidant treatment tanks, and said biological treatment tank. The ultrasonic generator of claim 8, wherein the ultrasonic generator is configured to be detachable from the two low frequency and high frequency ultrasonic wave / oxidant treatment tanks so as to be repaired or replaced. An apparatus for treating industrial wastewater, characterized in that the direct contact is made by dipping directly into the industrial wastewater having been pretreated. The method of claim 8, wherein the oxidant dispersing tube is made of a small perforated tube or a dispersing device having the same function, and is installed between one side wall of the ultrasonic / oxidant treatment tank and the low frequency and high frequency ultrasonic wave generators. An industrial wastewater treatment apparatus.