JP2007029825A - Apparatus for treating waste water and method for treating waste water using the apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for treating organic substance-containing waste water capable of efficiently and also sufficiently decomposing drainage including various kinds of pigments, dyes, organic resins, detergents, fats and fatty oils and other organic components such as coating drainage, and containing a solid component, an easily decomposable component, a hardly decomposable component, a hydrophobic organic substance, a hydrophilic organic substance or the like; and a method for treating it. <P>SOLUTION: The apparatus comprises a flocculation treatment device 1 for carrying out flocculation treatment of the coating-containing waste water to remove primary treatment water, an activated sludge treatment device 2 for carrying out activated sludge treatment of the primary treatment water to remove secondary treatment water and an accelerated oxidation treatment device 3 for carrying out accelerated oxidation treatment of the secondary treatment water to remove tertiary treatment water. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a wastewater treatment apparatus for organic matter-containing wastewater and a wastewater treatment method using this apparatus.

Conventionally, industrial wastewater such as paint wastewater discharged from paint factories and wastewater containing a large amount of organic matter such as agricultural wastewater are subjected to physical treatment such as coagulation separation (floating or sedimentation) treatment or ultrafiltration, and then activated sludge method. Is generally biologically treated under aerobic conditions.
For example, in paint wastewater treatment, a treatment method in which biological treatment is performed after SS components are removed by coagulation treatment is generally employed (see Patent Document 1 below).
In addition, a treatment method has been proposed in which, after the paint wastewater is biologically treated, a flocculant is added to perform a coagulation sedimentation treatment to reduce the amount of generated sludge (see Patent Document 2 below).

  On the other hand, many methods using physical and chemical treatment methods such as ozonolysis method, Fuenton method, and UV irradiation method as well as biological treatment have been proposed for the treatment of wastewater containing such a large amount of hardly decomposable substances. It was. For example, a treatment method is disclosed in which wastewater containing organic matter is oxidatively decomposed by irradiating ultraviolet rays and / or visible light in the presence of a photo-oxidation catalyst (see Patent Document 3 below).

JP-A-6-55172

JP 2003-39078 A

JP-A-8-155308

  As shown in Patent Documents 1 and 2, the ordinary activated sludge method has a limit in the ability of microorganisms to decompose organic matter, and this method leaves water-soluble organic substances containing nitrogen that are difficult to decompose, such as nitrogen. There is a problem that it remains in the treated water, or even if it can be treated, it needs to be treated for a very long time.

  In particular, in the case of water-based paint wastewater, the paint wastewater contains a large amount of components that dissolve in water, so the organic concentration of the primary treatment water after physicochemical treatment such as coagulation sedimentation is higher than that of oil-based paint. Become. For this reason, in the conventional biological treatment performed after physicochemical processing, it becomes a heavy load and the problem that organic matter cannot be processed completely arises. In addition, the biopersistent organic matter contained in the water-based paint cannot be processed and remains.

  In Patent Document 2, the main purpose is to separate and remove the SS component, and although BOD and COD are halved, the concentration is still as high as 10,000 to 15000 mg / L, and the burden on biological treatment is reduced. It has not been. In addition, this method still has the problem that the biodegradable substances cannot be removed.

  Further, as described above, Patent Document 3 discloses a treatment method for oxidatively decomposing wastewater containing organic matter by irradiating ultraviolet rays and / or visible light in the presence of a photooxidation catalyst. In many cases, it is difficult to sufficiently decompose the pollutant, and even if it can be decomposed, it takes a lot of time and cost for the treatment. Taking paint wastewater as an example, wastewater contains various pigments, dyes, organic resins, crosslinking agents, organic solvents, surfactants, fats and oils, and other organic components. It fluctuates depending on the type of plant, the source factory, and the time zone in which it occurs, and is not constant.

  In addition, these components are also characterized by the fact that their water solubility, physical and chemical decomposability, and biodegradability are very different from each other. When organic substances that are not sufficiently decomposed remain in the treated water by physical or chemical treatment methods such as chemical and UV irradiation methods, or by ordinary methods such as activated sludge method, it is not effective as a treatment method There are many.

  Thus, various pigments such as paint wastewater, dyes, organic resins, crosslinking agents, organic solvents, surfactants, oils and fats, and other organic components, solid components, easily decomposable components, hardly decomposable components Alternatively, an appropriate treatment method has not been established as a treatment method for wastewater having a complicated organic composition such as a hydrophobic organic material or a hydrophilic organic material.

  An object of the present invention is to provide a treatment apparatus and treatment method for organic matter-containing wastewater that can efficiently and sufficiently decompose various organic matters contained in such waste water.

  As a method for solving the above-mentioned problems, first, organic substance-containing wastewater is subjected to primary treatment using an electrolytic treatment device and / or a coagulation treatment device, then subjected to secondary treatment using an activated sludge treatment device, and then to an accelerated oxidation treatment device. The present inventors have found that wastewater containing various organic substances can be efficiently treated by performing a hardly decomposable treatment. Specifically, it is as follows.

  That is, the invention according to claim 1 of the present invention is an electrolytic treatment apparatus and / or a coagulation treatment apparatus for taking out an organic substance-containing wastewater by electrolytic treatment and / or coagulation treatment to extract primary treatment water, and the primary treatment water is treated with activated sludge. It comprises an activated sludge treatment device for treating and taking out secondary treated water, and an accelerated oxidation treatment device for taking out the tertiary treated water by promoting oxidation treatment of the secondary treated water.

  In the invention according to claim 4 of the present invention, the waste water containing organic matter is introduced into the electrolytic treatment apparatus and / or the coagulation treatment apparatus, and the primary treatment water is taken out by performing the electrolytic treatment and / or the coagulation treatment. A first step, a second step of taking out the secondary treated water by introducing the primary treated water into the activated sludge treatment apparatus, and performing an activated sludge treatment for solid-liquid separation of the activated sludge mixed liquid in the apparatus; and And a third step of taking out the tertiary treated water by introducing the secondary treated water into the accelerated oxidation treatment apparatus and performing the accelerated oxidation treatment.

Here, the organic substance-containing wastewater is industrial wastewater, agricultural wastewater, domestic wastewater, or the like discharged from factories or offices, and particularly includes paint wastewater. Examples of the paint wastewater include paint lines for automobiles and various industrial products, paint booth water at a sheet metal factory, drainage containing paint components from a paint manufacturing factory, and washing water at various factories. For example, when an example of the waste water of the painting line of an automobile is given, the deposit is 1 to 100 g / L, COD _Mn is 1000 to 10000 mg / L, TOC is 1000 to 15000 mg / L, BOD is 1000 to 5000 mg / L, and organic The solvent was about 1 to 10,000 mg / L. The COD _Mn is the chemical oxygen demand, the TOC is the total organic carbon content, and the BOD is the biochemical oxygen demand.

(Operational effects in electrolytic treatment equipment and coagulation treatment equipment)
The organic matter-containing wastewater contains a large amount of solids such as resins, pigments, and curing agents. Therefore, in the inventions according to claim 1 and claim 4, an aggregating treatment in which an aggregating agent is first added to agglomerate and separate the solids, An electrolytic treatment for separating the solid content and removing the solid content is performed. Thereby, the primary treatment water with TOC reduced from 10000 to 15000 mg / L to 5000 to 10000 mg / L can be obtained.

  Examples of the coagulant used in the coagulation sedimentation separation include inorganic coagulants represented by aluminum sulfate, polyaluminum chloride, ferric chloride, and the like, low molecular coagulants such as surfactants, anionic and weak anions. , Nonionic or cationic polymer flocculants can be used, and these can be used alone or in combination of two or more according to the type of waste water.

  In addition, the electrolytic treatment is to charge and dissolve the electrolyte in the supplied wastewater, place a plurality of electrodes in the water tank at an appropriate interval, energize between the electrodes, and perform electrolysis of water, In this method, fine bubbles of oxygen and hydrogen generated by the electrolysis of water are used to adsorb pigments, resins, and the like in the waste water, and collect these substances on the surface of the wastewater by the buoyancy of the bubbles. This method is also effective when combined with the above aggregation treatment. It is preferable to use an aluminum electrode as the electrode and sodium nitrate or sodium chloride as the electrolyte.

(Functional effects in activated sludge treatment equipment)
Even after treatment with a flocculant using the aggregating treatment apparatus or electrolytic treatment using the electrolytic treatment apparatus, hydrophilic organic solvents, some resins, curing agents, etc. remain in the waste water. To do. For this reason, in the present invention, as the secondary treatment following the above treatment, the primary treated water is introduced into the activated sludge treatment apparatus to perform the activated sludge treatment, and the secondary treated water is obtained by solid-liquid separation. Under the present circumstances, since solid content is previously removed in the above-mentioned coagulation process and / or electrolytic process, biological treatment can be advanced efficiently in the activated sludge process. Examples of the solid-liquid separation means include gravity sedimentation and separation by membrane (membrane separation activated sludge method).

In the secondary treatment water, biodegradable organic matter contained in the organic matter-containing wastewater is almost completely removed. However, since the hardly decomposable organic matter remains, BOD is 5 to 10 mg / L, and TOC is 300 to 300. The treated water quality (water quality of secondary treated water) is about 1000 mg / L and COD _Mn is about 300 to 1000 mg / L.

(Operational effects in the accelerated oxidation treatment equipment)
As described above, in the secondary treatment water obtained by the activated sludge treatment, the hardly decomposable organic matter remains. Therefore, in the present invention, the secondary treatment water from the activated sludge treatment apparatus is introduced into the accelerated oxidation treatment apparatus to decompose the hardly decomposable organic matter that cannot be treated by biological treatment.

  The accelerated oxidation treatment mainly includes a method in which ozone, hydrogen peroxide, and ultraviolet oxidants are combined. It is desirable to employ two or three of these oxidants in combination. In addition, when waste water containing various components such as paint waste water and containing a large amount of solids is subjected to accelerated oxidation treatment, the efficiency is greatly reduced, but in the present invention, the solid treatment is performed in the primary treatment and the secondary treatment. Since the treated water after removing the organic matter that is easily separated and biodegradable is subjected to accelerated oxidation, its properties are stable and the accelerated oxidation treatment can be performed efficiently.

The invention described in claim 2 is the invention described in claim 1, characterized in that the organic matter-containing wastewater is paint-containing wastewater.
The invention described in claim 5 is the invention described in claim 4, characterized in that the organic matter-containing wastewater is paint-containing wastewater.
Among organic matter-containing wastewater, paint-containing wastewater contains various components as described above and contains a large amount of solids, which makes it difficult to treat. However, according to the present invention, paint-containing wastewater can be easily and quickly treated. It can be processed efficiently and sufficiently.

The invention according to claim 3 is the invention according to claim 1 or 2, further comprising a biological treatment apparatus for biologically treating the tertiary treated water.
The invention described in claim 6 is the invention described in claim 4 or 5, further comprising a fourth step of biologically treating the tertiary treated water.

  In general, in the oxidation treatment using ozone, there is a phenomenon in which part of the biodegradable organic matter is converted into partly biodegradable organic matter as the amount of ozone added increases, and the BOD once increases and then decreases. It is known. Even in the organic matter-containing wastewater in the present invention, the TOC decreases with the injection of the oxidizing agent, whereas the BOD may rise to 100 mg / L or more.

  In the invention according to claim 3 and claim 6, which corresponds to such a phenomenon, the biologically degradable organic matter produced by the biological treatment after the accelerated oxidation treatment is used for biological treatment. It is surely removed.

The invention described in claim 7 is characterized in that, in the invention described in claim 6, activated sludge treatment and / or biological activated carbon treatment is used as the biological treatment.
Examples of biological treatment include activated sludge treatment and biological activated carbon treatment, but the present invention is not limited to these.

  According to the treatment apparatus and the treatment method of the present invention, organic substances contained in waste water can be efficiently and sufficiently treated. In particular, when applied to wastewater containing various organic components at high concentrations, such as paint wastewater, the primary treatment removes solids and hydrophobic organic substances, and the secondary treatment removes easily degradable organic substances. It is possible to remove sludge generated in large quantities while decomposing, and then to process persistent organic substances in tertiary treatment, so that most organic substances contained in wastewater can be processed continuously with high efficiency. There is an excellent effect that it becomes possible.

  Hereinafter, the present invention will be described in more detail with reference to FIG. 1 and FIG. 2, but the present invention is not limited to the following best modes at all, and may be appropriately modified and implemented without departing from the scope of the present invention. It is possible to do. FIG. 1 is a flowchart showing the best mode 1 of the present invention, and FIG. 2 is a flow chart showing another best mode 2 of the present invention.

(Best Mode 1)
As shown in FIG. 1, the waste water treatment apparatus according to the best mode 1 includes a coagulation sedimentation treatment apparatus 1 including a coagulation sedimentation tank that adds a coagulant and removes a solid content, and the coagulation sedimentation treatment apparatus 1. It has an activated sludge treatment device 2 that treats primary treated water with activated sludge, and an accelerated oxidation treatment device 3 that includes an accelerated oxidation treatment tank that promotes oxidation treatment of secondary treated water from the activated sludge treatment device 2. . In FIG. 1, 4 is a transfer pump for supplying organic substance-containing wastewater to the coagulation sedimentation treatment apparatus 1, 5 is an aeration blower, and 7 is secondary treatment water from the activated sludge treatment apparatus 2 to the accelerated oxidation treatment apparatus 3. A transfer pump for supply, 8 is a hydrogen peroxide supply device, and 9 is an ozone generator.

The treatment of the organic matter-containing wastewater using the wastewater treatment apparatus is performed as follows.
First, the organic matter-containing wastewater is supplied to the coagulation sedimentation processing apparatus 1 by the transfer pump 4, and the solid content is removed by adding the coagulant here (first step).
Next, the coagulated sediment supernatant (primary treated water) is supplied to the activated sludge treatment apparatus 2 and subjected to activated sludge treatment. Specifically, the processing is performed by aeration with the aeration blower 5 and gravity sedimentation in the sedimentation tank 6 (second step).

  Finally, the treatment liquid (secondary treatment water) from the activated sludge treatment apparatus 2 is supplied to the accelerated oxidation treatment apparatus 3 by the transfer pump 7. Here, an oxidizing agent is supplied by the ozone generator 8 and the hydrogen peroxide supply device 7, and an accelerated oxidation treatment is performed to obtain final treated water (third step).

(Best Mode 2)
As shown in FIG. 2, the wastewater treatment apparatus according to the best mode 2 is an electrolytic treatment apparatus 11 that removes solids deposited and floated by electrolytic treatment, and activated sludge treatment of primary treated water from the electrolytic treatment apparatus 11. The membrane separation activated sludge treatment device 12 to perform, the accelerated oxidation treatment device 13 for promoting oxidation treatment of the secondary treated water from the membrane separation activated sludge treatment device 12, and the oxygen for supplying oxygen to the waste water from the promotion oxidation treatment device 13 It has the supply apparatus 14 and the biological activated carbon tower 15 which performs biological treatment.

  In FIG. 2, 16 is a transfer pump for supplying organic substance-containing wastewater to the electrolytic treatment apparatus 11, 17 is an electrode, and 18 is the primary treatment water from the electrolytic treatment apparatus 11 to the membrane separation activated sludge treatment apparatus 12. , 19 is a submerged membrane separator, 20 is an aeration blower, 21 is a transport pump for supplying secondary treated water from the membrane separation activated sludge treatment device 12 to the accelerated oxidation treatment device 13, and 22 is peroxidation. A hydrogen supply device, 23 is an ozone generator, 24 is an aeration blower for biological activated carbon, and 25 is a circulation pump for circulating treated water between the oxygen supply device 14 and the biological activated carbon tower 15.

The treatment of the organic matter-containing wastewater using the wastewater treatment apparatus is performed as follows.
First, the organic matter-containing wastewater is supplied to the electrolytic treatment apparatus 11 by the transfer pump 16 and is subjected to electrolytic treatment by the electrolytic treatment apparatus 11 to remove the solid content that precipitates and floats.
Next, the electrolyzed primary treated water is supplied from the upper part to the membrane separation activated sludge treatment device 12 by the transfer pump 18 and used for the activated sludge treatment. The submerged membrane separation device 19 is installed in the membrane separation activated sludge treatment device 12 and is sucked under reduced pressure by the transfer pump 21 so that the activated sludge in the membrane separation activated sludge treatment device 12 is sludge and treated water. Solid-liquid separation. Here, in the membrane separation activated sludge treatment apparatus 12, the aeration process is performed by the air from the aeration blower 20 disposed below the submerged membrane separation apparatus 19. As a result, oxygen can be supplied to the activated sludge, and cleaning of the membrane surface in the submerged membrane separation device 15 is ensured. In addition, as an immersion membrane used for the immersion membrane separation apparatus 15, inorganic membranes, such as various organic membranes or ceramics, can be used. Further, the membrane separation activated sludge treatment device 12 is provided with a sludge extraction device (not shown), and the activated sludge increased by this sludge extraction device is discharged out of the system as needed.

  The secondary treated water that has been subjected to the membrane separation activated sludge treatment is sent to the accelerated oxidation treatment device 13 by the transfer pump 21. In this accelerated oxidation treatment device 13, an oxidizing agent is supplied from the ozone generator 22 and the hydrogen peroxide supply device 12, and the accelerated oxidation treatment is performed.

The treated water subjected to the accelerated oxidation treatment is sent to the biological activated carbon tower 15 via the oxygen supply device 14. The biological activated carbon tower 15 is filled with activated carbon 26, to which microorganisms are attached. The oxygen supply device 4 and the biological activated carbon tower 5 are circulated by a circulation pump 25, and the treated water is always in contact with the activated carbon 16, so that biological treatment is performed. The treated water flowing out from the biological activated carbon tower 5 is the final treated water.
[Other matters]
(1) In the best modes 1 and 2 described above, primary treatment water is taken out by performing electrolytic treatment or agglomeration treatment in the first step. However, the present invention is not limited to such a method. Of course, the primary treated water may be taken out by performing the treatment together.
(2) In the above best mode 2, the biological activated carbon treatment is used as the biological treatment carried out after the accelerated oxidation treatment. However, the biological activated carbon treatment is not limited to such treatment, and may be activated sludge treatment. Of course, both the treatment and the activated sludge treatment may be used.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
Electrolytic treatment, membrane-separated activated sludge treatment, and accelerated oxidation treatment were performed on wastewater from the painting line.
First, in the electrolytic treatment, an electrolytic treatment apparatus equipped with an aluminum electrode was used, and the electrolytic treatment was performed at 5 V for 60 minutes to remove the solid content precipitated and floated.

Next, the membrane separation activated sludge treatment was operated under the following conditions.
・ MLSS 18000mg / L
・ BOD sludge load 0.13 kg / kg / day ・ Residence time 4 days

Finally, the accelerated oxidation treatment was operated under the following conditions.
・ Ozone addition rate 1800mg / L
・ Hydrogen peroxide addition rate 100mg / L
Table 1 shows the water quality when treated under the above conditions.

As is apparent from Table 1 above, it can be seen that SS can be greatly reduced by electrolytic treatment, and solids in wastewater can be largely removed. It is also recognized that TOC and COD _Mn are reduced to 1/2 to 1/3, and hydrophobic organic substances can be removed.
Further, 99% of BOD can be removed by membrane separation treatment, and 90% or more of COD _Mn and TOC can be removed, and it is recognized that easily decomposable organic substances can be removed here.

Furthermore, the TOC and COD _Mn remaining by the accelerated oxidation treatment decreased to 65 mg / L and 15 mg / L, respectively, and the organic matter that could not be decomposed by the biological treatment was decomposed by the accelerated oxidation treatment. Is recognized.

(Example 2)
The membrane separation activated sludge treatment was performed in the same manner as in Example 1 above.
And since the relationship between ozone consumption and BOD when the membrane separation treated water was subjected to accelerated oxidation treatment by batch treatment, and the ozone consumption and COD _Mn were examined, those results are shown in FIG. 3 and FIG. 4 shows.

As is apparent from FIG. 3, it is recognized that the value of COD _Mn decreases as the ozone consumption increases. On the other hand, as is clear from FIG. 4, BOD was 8.4 mg / L before the accelerated oxidation treatment, but increased to a maximum of 190 mg / L when the ozone consumption was 1000 mg / L. It can be seen that it decreases with increasing. From these facts, it is understood that the ozone consumption in the accelerated oxidation treatment can be reduced by installing the biological treatment apparatus after the accelerated oxidation treatment.

  The present invention can be applied to wastewater treatment of organic matter-containing wastewater, and is particularly suitable for wastewater treatment of paint-containing wastewater.

It is a flowchart of the waste water treatment apparatus concerning the best form 1 of this invention. It is a flowchart of the wastewater treatment apparatus concerning the best form 2 of this invention. It is a graph which shows the relationship between COD _Mn amount and ozone consumption. It is a graph which shows the relationship between BOD amount and ozone consumption.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coagulation sedimentation processing apparatus 2 Activated sludge processing apparatus 3 Accelerated oxidation processing apparatus 11 Electrolytic processing apparatus 12 Membrane separation activated sludge processing apparatus 13 Accelerated oxidation processing apparatus 14 Oxygen supply apparatus 15 Biological activated carbon tower

Claims (7)

An electrolytic treatment device and / or a coagulation treatment device for taking out the primary treated water by electrolytic treatment and / or agglomeration treatment of the waste water containing organic matter;
An activated sludge treatment apparatus for treating the primary treated water with activated sludge to take out the secondary treated water;
An accelerated oxidation treatment apparatus that accelerates the secondary treated water to extract tertiary treated water;
A wastewater treatment apparatus comprising:   The wastewater treatment apparatus according to claim 1, wherein the organic matter-containing wastewater is paint-containing wastewater.   The wastewater treatment apparatus according to claim 1 or 2, further comprising a biological treatment apparatus for biologically treating the tertiary treated water. A first step of introducing the organic substance-containing wastewater into the electrolytic treatment device and / or the coagulation treatment device and taking out the primary treated water by performing the electrolytic treatment and / or the coagulation treatment;
A second step of taking out the secondary treated water by introducing the primary treated water into the activated sludge treatment apparatus and subjecting the activated sludge mixed liquid in the apparatus to solid-liquid separation;
A third step of introducing the secondary treated water into the accelerated oxidation treatment apparatus and taking out the tertiary treated water by performing the accelerated oxidation treatment;
A wastewater treatment method characterized by comprising:   The wastewater treatment method according to claim 4, wherein the organic matter-containing wastewater is paint-containing wastewater.   The wastewater treatment method according to claim 4 or 5, further comprising a fourth step of performing biological treatment on the tertiary treated water.   The wastewater treatment method according to claim 6, wherein activated sludge treatment and / or biological activated carbon treatment is used as the biological treatment.