JP2008207122A - Apparatus and method for treating organic matter-containing water - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To treat organic matter-containing water containing a surfactant and a BOD component while preventing the excess and deficiency of the amount of ozone to be added. <P>SOLUTION: The upper end height (the interface height with an air layer) of a foamy layer B in an ozone reaction tank 11 is measured by using an interface detector L. The measured interface height is input as an input value in a controller 30 composed of a computer, in which a program for calculating the surfactant concentration according to beforehand-derived calculating formula is stored, and the like. The controller 30 outputs a control signal for controlling the amount of the ozone gas to be generated in an ozone generator 20 according to the calculated surfactant concentration. As a result, the ozone gas of the amount corresponding to that of the surfactant in the organic matter-containing water flowing in the ozone reaction tank 11 is supplied to the ozone reaction tank 11. The organic matter-containing water ozonized in the ozone reaction tank 11 is treated in a biological treatment tank 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a treatment apparatus and treatment method for organic substance-containing water containing a surfactant and an organic substance. In particular, the present invention relates to a treatment apparatus and treatment method for organic substance-containing water including ozone treatment in which a surfactant is oxidized by ozone.

  Conventionally, as a method for treating surfactant-containing water, an activated carbon adsorption method, a foam separation method, a biological treatment method, an oxidation treatment using an oxidant such as ozone, and the like are known. Among surfactants, alkylphenol type nonionic surfactants and alkyl ether type nonionic surfactants having an ethylene oxide (EO) chain are more biological than linear alkylbenzene sulfonic acid (LAS). It is difficult to be disassembled.

  In semiconductor manufacturing factories and liquid crystal manufacturing factories, ether type surfactants such as polyethylene alkyl ether (APE) are often used in the product manufacturing process. For this reason, wastewater discharged from semiconductor and liquid crystal manufacturing factories contains these biodegradable surfactants, and ozone has been conventionally used for the treatment. In addition, a treatment method in which treatment by addition of hydrogen peroxide, ultraviolet irradiation, oxidation catalyst addition, alkali addition, or the like is appropriately combined with ozone treatment has been proposed (for example, Patent Document 1).

  By the way, the discharge | emission amount of the waste_water | drain containing surfactant, and the content rate of surfactant are not necessarily constant. For this reason, the amount of ozone added may be excessive or too small depending on the amount of wastewater to be treated (treated water) and the surfactant concentration. If the amount of ozone added is insufficient, the oxidative decomposition of the surfactant will be insufficient. On the other hand, if the amount of ozone added is excessive, it will be uneconomical and the amount of excess ozone will increase. Becomes higher.

In order to optimize the ozone addition amount, a method of measuring the surfactant concentration of the water to be treated and controlling the ozone addition amount according to the surfactant concentration can be considered. Examples of the device for measuring the surfactant concentration to control the amount of ozone added include an organic concentration meter (TOC) meter and a fluorescence spectrophotometer. For example, Patent Document 2 discloses an ozone addition amount control apparatus using a fluorescence spectrophotometer.
JP 2000-271577 A Japanese Patent No. 3606021

  Wastewater discharged from semiconductor and liquid crystal manufacturing factories contains various organic chemicals in addition to surfactants. As these organic chemicals, isopropyl alcohol (IPA), tetramethylammonium hydroxide (TMAH) used as a developer, monoethanolamine (MEA), and the like are often used.

  The above-described IPA and the like are easily biodegraded but are not easily ozonolyzed. For this reason, it is not always easy to treat the water to be treated containing IPA or the like and a surfactant in combination with ozone treatment and biological treatment, and it is particularly difficult to add ozone without excess or deficiency. .

  For example, when it is intended to control the amount of ozone added using a TOC meter, the TOC meter measures not only the surfactant but also the concentration of organic substances including IPA that is not easily decomposed by ozone and easily biodegraded. The amount of ozone required for the oxidative decomposition of can not be grasped. On the other hand, when using a fluorescence spectrophotometer, it is possible to detect the concentration of only the surfactant as a measurement target. However, the fluorescence spectrophotometer is more complicated and expensive than the TOC meter, and on-line measurement is difficult. Therefore, the control of the ozone addition amount is delayed.

  The present invention has been made in view of the above problems, and provides a treatment apparatus and treatment method capable of treating wastewater containing a surfactant that is not easily biodegraded and an organic substance such as IPA that is easily biodegraded by adjusting the amount of ozone added. The purpose is to do.

  The present inventors have found that the above problem can be achieved by optimizing the amount of ozone added using foaming in an ozone reaction tank for performing ozone treatment, and have completed the present invention. Specifically, the present invention provides the following.

(1) In an apparatus for treating organic substance-containing water containing a surfactant and a BOD component containing an ozone reaction tank and a biological treatment tank, an ozone generator for supplying ozone gas to the ozone reaction tank, and the inside of the ozone reaction tank An interface detector that measures the foam layer interface height and outputs the measurement result as a first signal; a controller that receives the first signal and controls the amount of ozone gas supplied from the ozone generator; An organic matter-containing water treatment apparatus further comprising:
(2) It further includes a flow meter that measures an inflow amount of the organic substance-containing water introduced into the ozone reaction tank and outputs a measurement result as a second signal, and the controller includes the first signal and the second signal. The amount of the surfactant brought into the ozone reaction tank is calculated from the inflow amount of the organic substance-containing water introduced into the ozone reaction tank and the surfactant concentration, and from the ozone generator. The apparatus for treating organic substance-containing water according to (1), which controls an ozone supply amount.
(3) The apparatus for treating organic matter-containing water according to (1) or (2), wherein the biological treatment tank is disposed downstream of the ozone reaction tank.
(4) In the processing method of the organic substance containing water which processes the organic substance containing water containing surfactant and a BOD component with an ozone reaction tank and a biological treatment tank, the foam layer interface height in the said ozone reaction tank is measured, The processing method of the organic substance containing water which calculates | requires the surfactant density | concentration of the said organic substance containing water which flows in into the said ozone reaction tank from foam layer interface height, and controls the amount of ozone supplied to the said ozone reaction tank.
(5) The amount of the organic substance-containing water flowing into the ozone reaction tank is measured, and the surface activity brought into the ozone reaction tank from the amount of the organic substance-containing water flowing into the ozone reaction tank and the surfactant concentration The method for treating organic substance-containing water according to (4), wherein the amount of the agent is calculated and the amount of ozone supplied to the ozone reaction tank is controlled.

  The present invention treats organic-containing water containing a surfactant and a BOD component. In particular, it is suitable for the treatment of water containing organic matter containing a surfactant that is easily decomposed by ozonolysis and hardly biodegradable and a BOD component that is hardly decomposed by ozone and easily biodegraded. Examples of the former include alkyl ether type, alkyl ester type, and alkylphenol type nonionic surfactants having an EO chain. If the concentration is about 0.1 to 20 mg / L, it is suitable for the treatment according to the present invention. Examples of the latter include IPA, TMAH, and MEA.

  The controller only needs to control the amount of ozone added by controlling the output of the ozone generator or controlling the flow rate of ozone gas supplied from the ozone generator to the ozone reaction tank. For example, the controller receives the foam layer upper end height in the ozone reaction tank measured by the interface detector as an input value, and calculates the surfactant concentration of the organic-containing water supplied to the ozone reaction tank (concentration) A computer for storing a calculation program). The controller has an arithmetic processing unit that performs arithmetic processing by the program using the input foam layer upper end height information as an input value, and further, an output for controlling the ozone supply amount according to the calculated surfactant concentration Configure to emit a signal.

  According to the study by the present inventors, the foam layer interface height of the ozone reaction tank and the surfactant concentration of the organic substance-containing water have a proportional relationship. Therefore, the concentration calculation program can be created by obtaining a relationship between the foam layer interface height of the ozone reaction tank and the surfactant concentration of the organic substance-containing water in a preliminary experiment or the like.

  The present invention can be suitably used when the surfactant concentration of organic substance-containing water introduced into an ozone reaction vessel varies. If the inflow amount of organic substance-containing water introduced into the ozone reaction tank also fluctuates, measure the inflow amount using a flow meter that measures the inflow amount. Another program for determining the inflow amount of the surfactant itself may be further stored in the controller.

  By the ozone treatment, the surfactant contained in the organic substance-containing water is decomposed into an organic acid or the like. An organic acid or the like generated by ozonolysis of a surfactant is a BOD component and is easily biodegraded. Therefore, biological treatment is preferably performed after ozone treatment. However, the flow of decomposing biologically indegradable organic substances by ozone treatment after biological treatment prior to ozone treatment and biological decomposition of BOD components is not excluded from the scope of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the organic substance containing water containing surfactant and a BOD component can be processed by optimizing the addition amount of ozone.

  Hereinafter, the present invention will be described in detail with reference to the drawings. Hereinafter, the same members are denoted by the same reference numerals, and description thereof is omitted or simplified.

  FIG. 1 is a schematic diagram of an organic substance-containing water treatment apparatus (hereinafter simply referred to as “treatment apparatus”) 1 according to a first embodiment of the present invention. The processing apparatus 1 includes an ozone reaction tank 11, a biological treatment tank 12, an ozone generator 20, and a controller 30.

  A raw water pipe 15 and an ozone pipe 26 are connected to the ozone reaction tank 11. The ozone tube 26 is connected to the ozone generator 20. An oxygen pipe 25 is connected to the ozone generator 20. In the ozone generator 20, ozone gas is generated by using oxygen supplied from the oxygen tube 25 by silent discharge as a raw material. The ozone generator 20 is not limited to this, and an ultraviolet irradiation ozone generator or an electrolytic ozone generator that generates ozone by electrolyzing water may be used.

  The ozone gas generated by the ozone generator 20 is supplied from the ozone pipe 26 to the lower part of the ozone reaction tank 11. In the ozone reaction tank 11, a stagnation layer W made of organic substance-containing water supplied from the raw water pipe 15 is formed. The ozone gas supplied to the ozone reaction tank 11 ascends the stagnant layer W. Since the organic substance-containing water constituting the suspension layer W contains a BOD component and a surfactant, foaming occurs when ozone gas is blown from the diffuser into the suspension layer W, and a foam layer is formed on the suspension layer W. B is formed.

  In the ozone reaction tank 11, an interface detector L for measuring the height of the upper end of the foam layer B in the ozone reaction tank 11, that is, the position of the interface between the foam layer B and the gas layer above the ozone reaction tank 11 is installed. Has been. The type of the interface detector L is not limited, and a level meter or level switch such as a type that measures capacitance or potential difference (capacitance type or conductivity type), an ultrasonic type, or the like can be used.

  The interface detector L is connected to the controller 30 by a communication line N. The controller 30 is configured by a computer including an arithmetic processing unit that calculates the surfactant concentration of the organic substance-containing water from the interface height of the foam layer B. The computer constituting the controller 30 stores a concentration calculation program for calculating the surfactant concentration of the organic substance-containing water introduced into the ozone reaction tank 11 using the interface height of the foam layer B as an input value. .

  As will be described later, according to the study by the present inventors, there is a correlation between the thickness of the foam layer B formed in the ozone reaction tank 11 and the surface active concentration of organic substance-containing water introduced into the ozone reaction tank 11. And the program is constructed based on this knowledge. This will be specifically described below.

  First, the surfactant is obtained by introducing organic substance-containing water containing a surfactant having a known concentration into the ozone reaction tank 11 at a constant flow rate and determining the interface top height of the foam layer B formed by blowing ozone gas. A regression equation showing the relationship between the concentration and the foam layer B interface height is obtained. From the obtained regression formula, a calculation formula for calculating the surfactant concentration using the upper end height of the foam layer B interface as an input value is stored in the computer as a concentration calculation program.

  The amount of the surfactant brought into the ozone reaction tank 11 is the product of the inflow amount of the organic substance-containing water introduced into the ozone reaction tank 11 and the surfactant concentration. Therefore, when the inflow amount of the organic substance-containing water into the ozone reaction tank 11 is constant, an output signal for adjusting the output of the ozone generator 20 from the controller 30 according to the increase or decrease of the surfactant concentration is sent to the ozone generator 20. The ozone generation amount and the ozone concentration generated by the ozone generator 20 are increased or decreased. The controller 30 may control the flow rate of ozone gas flowing through the ozone pipe 26.

  When the inflow of organic substance-containing water into the ozone reaction tank 11 varies, the inflow of organic substance-containing water that has flowed into the ozone reaction tank 11 by providing a flow meter F in the raw water pipe 15 as shown in FIG. taking measurement. The computer constituting the controller 30 integrated the surfactant concentration calculated by the concentration calculation program and the inflow amount of organic substance-containing water measured by the flow meter F, and was brought into the ozone reaction tank 11. An absolute amount calculation program for calculating the surfactant amount is also stored. And what is necessary is just to send the output signal which adjusts the output of the ozone generator 20, etc. according to the calculation result of the program for absolute amount calculation.

In addition, in this embodiment, since the biological treatment tank 12 is arrange | positioned at the back | latter stage of the ozone reaction tank 11, in the ozone reaction tank 11, it is not necessary to decompose | disassemble a surfactant into an inorganic substance, and it becomes BOD components, such as an organic acid. It only needs to be disassembled. The amount of ozone added to decompose the surfactant into a biodegradable substance varies depending on the type of the surfactant, but is generally 4 to 6 g-O ³ / g-surfactant. may be a ^6g-O 3 / ^g- surfactants such degradation does not become insufficient.

According to the present invention, utilizing the fact that there is a correlation between the interface top height of the foam layer B in the ozone reaction tank 11 and the surfactant concentration of the organic substance-containing water, the interface of the foam layer B is measured, From the result, the ozone gas supply amount to the ozone reaction tank 11 is controlled to be constant at about 6 g-O ³ / g-surfactant. Therefore, it is possible to avoid excessive or excessive supply of ozone gas in the ozone reaction tank 11 and to decompose the surfactant into a biodegradable substance.

  In the processing apparatus 1, since the controller 30 and the interface detector L, the flow meter F, and the ozone generator 20 are connected by the communication line N, the measurement result of the interface detector L is output as the first signal. Then, the electric signal is automatically input to the controller 30 via the communication line N. Similarly, the measurement result of the flow meter F is output as a second signal and automatically input to the controller 30 via the communication line N as an electrical signal. The controller 30 outputs the calculation results of the concentration calculation program and the absolute amount calculation program, and the output signal is automatically transmitted to the ozone generator 20 via the communication line N as an electrical signal.

  Therefore, in the processing apparatus 1, the amount of ozone added is automatically controlled online, and it is possible to avoid the occurrence of a delay as in the case of using a fluorescence spectrophotometer. Moreover, since the interface detector is simpler and less expensive than the fluorescence spectrophotometer, the cost of the processing apparatus 1 can be reduced. The communication line N may be wired or wireless.

  The organic substance-containing water ozone-treated in the ozone reaction tank 11 configured as described above is sent to a biological treatment tank 12 connected to the ozone reaction tank 11 from a pump P provided in the middle of the feed pipe 16. The biological treatment tank 12 of the treatment apparatus 1 has a biological activated carbon layer that retains microorganisms such as activated sludge inside, and sprays outflow water (ozone treated water) from the ozone reaction tank 11 from above the biological activated carbon layer. Water is sprayed using the watering mechanism.

  The ozone-treated water contains an organic acid produced by decomposing the surfactant with ozone, and a BOD component such as IPA that is contained in the organic substance-containing water and has not been subjected to ozonization. In the biological treatment tank 12, the BOD component is biodegraded while the ozone treated water passes through the biological activated carbon layer. A treated water pipe 17 is connected to the lower part of the biological treatment tank 12, and treated water from which the BOD component has been removed from the ozone treated water is taken out from the treated water pipe 17.

  In addition, the ozone reaction tank 11 is comprised with the airtight container. For this reason, an exhaust ozone pipe 27 for extracting exhaust gas is connected to the upper part of the ozone reaction tank 11. When ozone gas is supplied to the ozone reaction tank 11 with some allowance so that ozone decomposition is not insufficient, ozone is contained in the exhaust gas. It may be connected to the device 22 to decompose ozone in the exhaust gas. If the dryer 21 is provided in the middle of the exhaust ozone pipe 27, excess humidity in the exhaust gas can be removed and the exhaust ozone can be efficiently decomposed.

  The biological treatment tank 12 is provided with a diffuser pipe 18 at the lower part of the biological treatment tank 12 for aerobically treating the BOD component, and oxygen-containing air or the like is also supplied from the diffuser pipe 18 into the tank. The Since the biological treatment tank 12 is composed of a sealed container, an exhaust pipe 19 is attached to the upper part of the biological treatment tank 12. However, the biological treatment tank 12 is not limited thereto, and may be an open aeration tank or the like. In addition, providing the biological treatment tank 12 in front of the ozone reaction tank 11 is not excluded from the scope of the present invention.

[Reference example]
An experiment for treating organic substance-containing water containing a surfactant and a BOD component was conducted using the treatment apparatus 2 shown in FIG. The processing apparatus 2 is different from the processing apparatus 1 of FIG. 1 in that an intermediate storage tank 13 is provided between the ozone reaction tank 11 and the biological treatment tank 12. The intermediate storage tank 13 is connected to the ozone reaction tank 11 by a feed pipe 16 and is connected to the biological treatment tank 12 by a second feed pipe 16B. A vortex pump P (manufactured by Nikuni Co., Ltd., M20NPD40S type) was provided in the middle of the second feed pipe 16B. The ozone reaction tank 11 was provided with a conductivity type level switch (manufactured by OMRON Corporation, PS-3S) as an interface detector. Moreover, as the ozone generator 20, the discharge voltage variable type ozone generator (Sumitomo Seimitsu Co., Ltd. make, GR-RD) was used. Other specifications of the processing apparatus 2 are shown below.

[Ozone reaction tank]
Transparent PVC cylindrical diameter; 150mm
Height: 4500 mm (height to the raw water pipe connection position is 3500 mm)
Flow rate: 500L / hr
[Biological treatment tank]
Transparent PVC cylindrical diameter; 190mm
Height: 2200mm
Packing layer (biological activated carbon layer) height: 1500mm
Flow rate (linear velocity LV): 15 m / h
[Intermediate storage tank]
Volume: 500L

  The organic substance-containing water used in the experiment contains 5 to 15 mg / L of APE as a surfactant and 1 to 10 mg / L of isopropanol, polyethylene glycol, TMAH, and OYOMEA as BOD components. Prior to the start of the experiment, the organic substance-containing water was introduced into the ozone reaction tank 11 at a constant flow rate under the above conditions while measuring the surfactant concentration of the organic substance-containing water, whereby the interface of the foam layer in the ozone reaction tank 11 was measured. The relationship between the height (that is, the height of the upper end) and the surfactant concentration of the organic substance-containing water was determined. The results are shown in FIG.

As shown in FIG. 3, it became clear that the surfactant concentration of the organic substance-containing water and the foam layer interface height in the ozone reaction tank 11 are proportional. Therefore, a program for calculating the surfactant concentration of the organic substance-containing water with the foam layer interface height X in the ozone reaction tank 11 as an input value is stored in the computer constituting the controller 30 by the calculation formula shown in Formula 1. I let you.
(Formula 1)
Surfactant concentration = 0.0138X + 42.841

[Example 1]
In Example 1, the foam layer interface height in the ozone reaction tank 11 was measured with a level switch, and the obtained measurement value was input to Equation 1 to calculate the surfactant concentration of organic substance-containing water. And the density | concentration of the ozone gas generated by controlling the voltage of the ozone generator 20 based on the calculation result was increased / decreased. Thus, was controlled to ozone amount to surfactant of the organic substance-containing water that has flowed into the ozone reaction vessel 11 is substantially constant at ^{6g-O 3 / g-TOC} (TOC as surfactants). In Example 1, the liquid in the tank was overflowed from the intermediate storage tank 13 at 75 L / h and discharged out of the system.

  In Example 1, the experiment was performed by varying the surfactant concentration of the organic substance-containing water in the range of 5 to 15 mg / L as described above. In Example 1, the surfactant concentration of the organic-containing water introduced into the ozone reaction tank 11, the foam layer interface height of the ozone reaction tank 11, the amount of ozone injected into the ozone reaction tank 11 (ozone addition amount), and the treatment Table 1 shows the TOC concentration of the treated water taken out from the water pipe 17.

[Comparative Example 1]
As Comparative Example 1, the interface height between the foam layer and the air layer in the ozone reaction tank 11 was not measured, and the ozone addition amount was constant at 15 g-O ³ / h. The experiment was conducted. The results are shown in Table 2.

[Comparative Example 2]
As Comparative Example 2, an experiment was performed under the same conditions as Comparative Example 1 except that the amount of ozone added was constant at 45 g-O ³ / h. The results are shown in Table 3.

  As shown in Tables 1 to 3, in Example 1 in which the interface height between the foam layer and the air layer of the ozone reaction tank 11 was measured and the ozone addition amount was controlled based on this measurement value, the TOC concentration of the treated water Was stable at around 1 mg / L. On the other hand, in Comparative Example 1 in which the amount of ozone added is constant when the surfactant concentration is 5 mg / L, when the surfactant concentration of the organic substance-containing water is increased, the treated water TOC concentration is 5 to 10 of Example 1. Sometimes it was about double. Further, in Comparative Example 2 in which the ozone addition amount was constant when the surfactant concentration was 15 mg / L, the TOC concentration of the treated water was equivalent to that in Example 1, but the ozone addition amount was excessive.

  As described above, according to the present invention, an organic substance-containing water containing a surfactant that is easily decomposed by ozonolysis and is not easily biodegraded and a BOD component that is not easily decomposed by ozone and is easily biodegraded can be treated by preventing excess and deficiency of the amount of ozone added. It was shown that it can be done.

  The present invention can be used for treatment of organic substance-containing water containing a surfactant and a BOD component.

The schematic diagram of the processing apparatus used for this invention. The schematic diagram of the processing apparatus used for the Example of this invention. The graph which shows the result obtained by the reference example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 2 Processing apparatus 11 Ozone reaction tank 12 Biological reaction tank 20 Ozone generator 21 Dryer 22 Waste ozone treatment apparatus 30 Controller

Claims (5)

In a treatment apparatus for organic matter-containing water containing a surfactant and a BOD component including an ozone reaction tank and a biological treatment tank,
An ozone generator for supplying ozone gas to the ozone reaction tank;
An interface detector for measuring the foam layer interface height in the ozone reaction tank and outputting the measurement result as a first signal;
And a controller that receives the first signal and controls a supply amount of ozone gas from the ozone generator. A flowmeter that measures the inflow of organic matter-containing water introduced into the ozone reaction tank and outputs the measurement result as a second signal;
The controller receives the first signal and the second signal, and a surfactant brought into the ozone reaction tank from an inflow amount of organic substance-containing water introduced into the ozone reaction tank and a surfactant concentration. The organic substance containing water treatment apparatus according to claim 1, wherein the amount of ozone is calculated to control an ozone supply amount from the ozone generator.   The apparatus for treating organic substance-containing water according to claim 1 or 2, wherein the biological treatment tank is disposed downstream of the ozone reaction tank. In the method for treating organic substance-containing water in which an organic substance-containing water containing a surfactant and a BOD component is treated in an ozone reaction tank and a biological treatment tank,
The amount of ozone supplied to the ozone reaction tank by measuring the foam layer interface height in the ozone reaction tank, determining the surfactant concentration of the organic substance-containing water flowing into the ozone reaction tank from the foam layer interface height For treating water containing organic matter.   The amount of the organic substance-containing water flowing into the ozone reaction tank is measured, and the amount of the surfactant brought into the ozone reaction tank from the amount of the organic substance-containing water flowing into the ozone reaction tank and the surfactant concentration The organic-containing water treatment method according to claim 4, wherein the amount of ozone supplied to the ozone reaction tank is controlled.

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