JP2003088892A - Organic waste water treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic waste water treatment apparatus in which the denitrification in the waste water is performed at a low cost. SOLUTION: The organic waste water treating apparatus 1 includes a pre- treating apparatus 100 for removing contaminants in the organic waste water, a biological treating apparatus 200 for biologically treating the waste water passed through the pre-treating apparatus and a physical and chemical treating apparatus 300 for physically and chemically treating the waste water passed through the biological treating apparatus.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an organic wastewater treatment apparatus. In particular, the present invention relates to an organic wastewater treatment apparatus which has a low running cost, is easy to operate, and can sufficiently remove nitrogen.

[0002]

2. Description of the Related Art Conventionally, if organic wastewater containing organic substances, nitrogen, and phosphorus generated in factories, households, etc. is discharged as it is, it causes environmental damage such as eutrophication of rivers. After the process, it may be discharged as treated water.

Among such waste treatment methods, a method of biologically decomposing organic wastewater and the like using microorganisms has become the mainstream. This biological treatment method
It is roughly divided into the following two formats. One is a method that does not consider the removal of nitrogen, specifically, a wet oxidation method or an aerobic digestion method. All of these promote the decomposition of organic substances by microorganisms under aerobic conditions, and decompose into CO ₂ and water. According to such a method, there are advantages that stable processing is possible and the operation of the device is relatively easy. However, there was a problem that the removal of nitrogen, which is the cause of eutrophication in public waters, was insufficient.

The other is a nitrification denitrification method in which nitrogen removal is considered, and examples thereof include a two-stage denitrification method and an intermittent aeration method. These decompose and remove nitrogen components such as ammonia as nitrogen gas from wastewater by the action of nitrifying bacteria and denitrifying bacteria under anaerobic or aerobic conditions. Therefore, although nitrogen removal is sufficiently achieved, there is a problem in that it is difficult to control aerobic and anaerobic conditions and load control in the biological treatment apparatus, and it requires a great deal of labor for operation management of the apparatus.

In recent years, as part of measures against environmental problems, it is required to purify industrial wastewater and domestic wastewater, and particularly to perform highly denitrifying treatment. Along with this, it is desired that even a device using any of the above-mentioned methods has a higher nitrogen removal effect and reduces the burden of operation management of the device.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic wastewater treatment apparatus which has a low running cost and is more excellent in denitrification effect than ever before.

[0007]

SUMMARY OF THE INVENTION In order to solve the above problems, the present invention provides an organic wastewater treatment apparatus including a pretreatment for removing impurities of the organic wastewater.
It is preferable that a solid-liquid separation device that removes the solid content of the wastewater that has passed through the biological treatment device is further included in the preceding stage of the physicochemical treatment device. The present invention also includes a pretreatment device for removing contaminants of organic wastewater, a physicochemical treatment device for physicochemically treating the wastewater that has passed through the pretreatment device, and a physicochemical treatment device. An organic wastewater treatment device comprising a biological treatment device for biologically treating wastewater. It is preferable to further include a solid-liquid separation device for removing solids of the wastewater that has passed through the biological treatment device. The biological treatment device is preferably a conventional treatment device such as various activated sludges utilizing microorganisms or wet oxidation. The physicochemical treatment device preferably uses ultrasonic waves or electromagnetic waves. Further, it is preferable that the solid-liquid separator is any one of a gravity settling device, a membrane separator, a centrifugal concentrator, or a device in which two or more of them are combined. Furthermore, the present invention, as another aspect, is an organic wastewater treatment method using these devices. By using such an organic wastewater treatment device, the denitrification effect is greatly improved compared to the conventional case, and the total nitrogen amount (TN) of the treated water is reduced to 10 mg / L or less. Further, it is possible to reduce the cost of the entire device and simplify the operation of the device.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an organic wastewater treatment apparatus according to the present invention will be described in detail with reference to the drawings. The following description does not limit the present invention.

FIG. 1 shows an embodiment of an organic wastewater treatment apparatus according to the present invention. In the organic wastewater treatment apparatus 1 according to the embodiment shown in FIG. 1, the pretreatment apparatus 100 removes contaminants or suspended substances (SS) contained in the organic wastewater. Next, the organic wastewater from which impurities and the like have been removed is sent to the biological treatment apparatus 200, and this apparatus decomposes the organic matter in the wastewater using microorganisms. The organic wastewater that has been subjected to biological treatment is processed by the subsequent physicochemical treatment device 300.
In the physicochemical treatment equipment, the substances remaining in the organic wastewater are removed by ultrasonic waves and electromagnetic waves. The organic wastewater that has been treated by these multiple treatment devices is SS,
Not to mention organic substances such as BOD and COD, nitrogen and phosphorus have been treated to the extent that they sufficiently meet the emission standards, and are recycled as treated water.

In the present invention, the organic wastewater means wastewater which may contain various solids such as human waste, and the organic wastewater treatment apparatus 1 according to the present invention treats such organic wastewater as a treatment target. There is. That is, as the processing object,
Various wastewaters such as industrial wastewater such as livestock wastewater and industrial wastewater can be mentioned. The components contained in such organic wastewater are removed by the following apparatus used in the organic wastewater treatment apparatus 1 according to the present invention.

The pretreatment apparatus 100 is an apparatus for mainly removing contaminants and / or suspended substances (SS) contained in the organic wastewater, specifically, solid contents such as vinyl, paper and cloth. Is. Therefore, in any of the embodiments of the organic wastewater treatment apparatus 1 according to the present invention, it is necessary to remove impurities by the pretreatment apparatus as the first step.

One of the embodiments of the pretreatment apparatus 100 is shown in FIG. The pretreatment device 100 includes a removing device 110,
It includes a mechanical solid-liquid separator 120 and a membrane separator 130. The debris removal device 110 is configured by a screen and is a device for removing contaminants such as paper and vinyl. The mechanical solid-liquid separation device 120 is a settling tank or a centrifuge, and is a device for separating organic wastewater to be treated into a separation liquid and sludge. The membrane separation device 130 is
It is a membrane separation device using a microfiltration membrane or an ultrafiltration membrane, and is mainly used for removing solid substances having a membrane pore size or a molecular weight cut off larger than that. It should be noted that one of the residue removal device 110 and the mechanical solid-liquid separation device 120 can be selected depending on the property of the wastewater to be treated. Also, the membrane separation device 130 can be omitted.

The organic wastewater treated by the pretreatment apparatus 100 has a portion of impurities and SS removed, and is supplied to the biological treatment of the next step. Note that the impurities and the like separated by the pretreatment device 100 can be treated by incineration or the like.

In the subsequent biological treatment apparatus 200, contaminants and sludge are removed, and the organic matter in the organic wastewater separated as the separation liquid is decomposed into carbon dioxide and water by the action of microorganisms. Such a device may be a device having a nitrogen removing function or a device not having a nitrogen removing function and intended only for organic substances, and various types of devices and methods can be used. Is.

As a specific example of an apparatus having a nitrogen removing function, an apparatus for performing nitrification and denitrification treatment can be mentioned.
The nitrification and denitrification treatment is to decompose pollutants in wastewater by the action of microorganisms. Biological treatment apparatus 20 used in organic wastewater treatment apparatus 1 according to the embodiment shown in FIG.
At 0, the BOD component, the nitrogen component (TN) containing ammonia and organic nitrogen, etc. are processed to carbon dioxide, water, and nitrogen gas.

Various devices can be appropriately used in the nitrification and denitrification process, and there is no limitation. In the present embodiment, a two-tank type nitrification denitrification treatment tank and a one-tank type nitrification denitrification treatment tank will be described as examples of the nitrification denitrification treatment apparatus. Generally, in the denitrification method by organisms, in an aerobic atmosphere created by aeration, nitrification reaction that oxidizes ammonia nitrogen contained in wastewater into nitrite nitrogen or nitrate nitrogen by the action of nitrifying bacteria, and the nitrite It is carried out by a denitrification reaction in which volatile nitrogen or nitrate nitrogen is reduced to nitrogen gas in an anaerobic atmosphere by the action of denitrifying bacteria.

Nitrifying bacteria and denitrifying bacteria play an important role in this biological denitrification method, but a carbon source is necessary for these bacteria to function. As for ammonia in waste water, NO _x (x = 2 or 3) is produced by reacting with oxygen in the nitrification tank as shown in the following formula (1). ^{_{NH 4 + + 3 / 2O 2}} → NO 2 - + 2H + + H 2 O ··· (1) In the denitrification reaction of the organism nitrogen removal method, the following (2)
Alternatively, the NOx-N generated by the nitrification reaction is decomposed by the formula (3) and rendered harmless. ^{_{NO 2 - + 3 (H 2}} ) → N 2 + 2OH - + 2H 2 O ··· (2) 2NO 3 - + 5 (H 2) → N 2 + 2OH - + 4H 2 O ··· (3)

In the two-tank nitrification / denitrification treatment tank 210 shown in FIG. 5, the nitrification reaction under an aerobic atmosphere and the denitrification reaction under an anaerobic atmosphere are carried out separately in the nitrification tank 211 and the denitrification tank 212. In the nitrification reaction in the aeration nitrification tank 211 under an aerobic atmosphere, the inflowing ammoniacal nitrogen can be reliably nitrified to nitrate nitrogen. Further, the biological treatment apparatus 200 used in the organic wastewater treatment apparatus 1 of the present invention may further include means for recovering and reusing a part of the nitrogen component in the wastewater by ammonia stripping. .

In addition, in the nitrification and denitrification treatment, an apparatus such as the one-tank type nitrification and denitrification treatment tank 220 shown in FIG. 6 can be used. In this treatment method, a high concentration and volume load of activated sludge were set in a complete mixing type reaction tank.
By intermittently introducing organic wastewater containing BOD components and controlling the amount of aerated air so that it is not too short or too short, the reaction of nitrification and denitrification can be performed simultaneously in a single reaction tank to improve reaction efficiency. It is a thing.

The biological treatment devices shown in FIGS. 5 and 6 are both applications of the present inventors.
No. 01-205295, and such an apparatus can be used in the present invention, but the present invention is not limited thereto.

In the present invention, it is also possible to use an apparatus for biological treatment which does not have a denitrification function. Such devices include, for example, an aerobic digestion / activated sludge treatment device or a wet oxidation / activated sludge treatment device.

The aerobic digestion / activated sludge device is a device for aerating a high-concentration organic wastewater for a long period of time under the aerobic condition by the action of microorganisms to oxidize and treat it. In this method, BOD, SS, etc. are mainly removed. Microorganisms ingest organic substances, oxidize and decompose them into nutrient sources, and release unnecessary inorganic compounds such as carbon dioxide and water. Ammonia is partially denitrified by an aerobic digestion / activated sludge treatment device, but its performance is generally insufficient and it is combined with oxygen by the action of microorganisms to form nitrous acid or nitric acid. The wet oxidation / activated sludge treatment device is a device that keeps waste water in a liquid state in a closed container together with air at high temperature and high pressure to thermally and oxidatively decompose organic substances.

In the biological treatment apparatus 200 used in the organic wastewater treatment apparatus 1 of the present invention, the decomposition of organic matter by microorganisms can be performed by the former apparatus considering nitrogen removal but by the latter apparatus not considering nitrogen removal. It may be. In the embodiment according to FIG. 1, particularly when a treatment method such as wet oxidation that does not take denitrification into consideration is used, and even if the nitrogen content remains, the nitrogen content is further removed in the subsequent physicochemical treatment. It is possible to eliminate and finally reduce T-N.

The organic wastewater that has been treated with microorganisms in the biological treatment apparatus 200 is decomposed into organic matter components, nitrogen components, etc., although it varies depending on the biological treatment apparatus.
It has been removed. The wastewater is sent to the physicochemical treatment device 300 in the next step and is used for further treatment.

The physicochemical treatment apparatus 300 in the organic wastewater treatment apparatus 1 of the present invention is irradiated with microwaves, ultrasonic waves in a low frequency range or the like to aggregate pollutants in wastewater and remove them as sludge. , A wastewater treatment method using ultrasonic waves or electromagnetic waves. In the embodiment shown in FIG. 1, the wastewater that has passed through the biological treatment apparatus 200 is subjected to physicochemical treatment.

By carrying out the physicochemical treatment, it is possible to remove organic substances, nitrogen components and phosphorus components which cannot be completely treated by the biological treatment. Organic wastewater treatment apparatus 1 of the present invention
The physicochemical treatment apparatus 300 according to (1) includes, for example, a pollutant separation means, a coagulation treatment means, a deodorization treatment means, and a high-pressure pulse treatment means, and the wastewater from the biological treatment apparatus 200 is collected by such means. It is something to process.

The pollutant separating means is a separating means for oscillating a microwave (300 MHz to 10.5 GHz) in raw water to separate pollutants and water. The pollutant here means BOD, T-N, T-P (total phosphorus amount) and the like. The aggregating means is a means for oscillating ultrasonic waves (50 kHz or less) in a low frequency region in the raw water after separation by the separating means to agglomerate and disperse the pollutants from water. The deodorizing treatment means is a means for oscillating a high frequency electromagnetic ultrasonic wave (3 M to 300 MHz) in the treated water to remove a bad odor from the treated water. What is high-voltage pulse processing means?
It is a means for decolorizing and sterilizing the treated water by applying a high-pressure pulse to the treated water to separate and remove nitrogen from the treated water and generate ozone.

A physicochemical treatment apparatus equipped with such means is disclosed in Japanese Patent Application No. 9-257137 (Japanese Patent Application Laid-Open No. 11-257137).
90420) to oscillate microwaves to separate raw water into pollutants and water, and then oscillate low-frequency ultrasonic waves into wastewater after such separation operation to aggregate the separated pollutants. In addition, there is one that oscillates electromagnetic ultrasonic waves in the high frequency range to deodorize wastewater. Further, the high-pressure pulse processing means can apply a high-pressure pulse to separate and remove nitrogen from the treated water and generate ozone to perform decolorization and sterilization of the treated water.

The physicochemical treatment apparatus 300 used in the organic wastewater treatment apparatus 1 of the present invention is not limited to the above-mentioned apparatus, and the applicant of the present invention uses fine bubbles for aggregating soluble substances. Application for Japanese Patent Application No. 11-34911
The physicochemical treatment can be carried out by using other methods such as the method according to No. 3 and the method according to Japanese Patent Application No. 2000-09810 filed by the applicant of the present application, which is a combination of high voltage pulse and electrolysis.

The treatment method using such a physicochemical treatment apparatus 300 can reduce the size of the water tank for performing such treatment, has low initial cost and running cost, and can be easily operated to contaminate the liquid. It is very advantageous in that it can remove substances and can simultaneously perform deodorization, decolorization, sterilization and the like. Therefore, the same effect as that of the present invention can be obtained not only by newly installing the organic wastewater treatment apparatus 1 according to the present invention but also by adding a physicochemical treatment apparatus to the conventional biological treatment apparatus. It is possible to obtain and it is very advantageous

The organic wastewater that has passed through the physicochemical treatment apparatus 300 is the already decomposed organic matter and the treated water from which the nitrogen content has been removed. In the embodiment of the organic wastewater treatment apparatus 1 according to the present invention, the treated water has a total nitrogen amount (TN).
Is reduced to 10 mg / L or less.

The first embodiment shown in FIG. 1 is an organic wastewater treatment apparatus 1 characterized by further performing a physicochemical treatment after the organic substance decomposing treatment utilizing microorganisms as described above. . Such a device is particularly advantageous in a biological treatment device in that it is possible to further highly remove residues containing carbon compounds, nitrogen compounds, and inorganic substances that have not been completely decomposed in the subsequent stage. In addition, it is advantageous in terms of cost by incorporating a physicochemical treatment that has a lower running cost than the conventional one.

Another embodiment of the organic wastewater treatment apparatus 1 according to the present invention is shown in FIG. In the organic wastewater treatment apparatus 1 shown in FIG. 2, the pretreatment apparatus 100 removes contaminants or suspended substances (SS) contained in the organic wastewater. Then, biological treatment is performed by the biological treatment apparatus 200 to decompose organic substances in the wastewater. Here, in the embodiment shown in FIG. 2, the solid content in the organic wastewater is removed by the solid-liquid separation device 400. That is, the excess sludge contained in the organic wastewater that has undergone biological treatment is extracted. The organic wastewater from which the excess sludge has been removed is processed by the subsequent physicochemical treatment device 30.
At 0, the treatment of ultrasonic waves and electromagnetic waves,
After removing phosphorus etc., it is regenerated as treated water.

This embodiment differs from the embodiment shown in FIG. 1 in that it further includes a treatment step between the biological treatment apparatus 200 and the physicochemical treatment apparatus 300 by the solid-liquid separation apparatus 400. Is. This is the solid-liquid separation device 4
00 is advantageous in that the solid content generated in the biological treatment is removed, the load on the subsequent physicochemical treatment apparatus 300 is reduced, and the treatment efficiency in the physicochemical treatment is increased.

The solid-liquid separation device 400 converts the organic wastewater that has undergone the decomposition treatment of organic substances by the biological treatment device 200 into
It separates into separated liquid and sludge. The solid-liquid separation operation here can be performed by a precipitation operation in a gravity settling apparatus, an operation by a centrifugal concentration apparatus, or a membrane separation apparatus such as a microfiltration membrane (MF membrane) or an ultrafiltration membrane (UF membrane).

The separated water thus separated is sent to the physicochemical treatment apparatus 300. Then, the separated sludge is sent to a composting device or the like after passing through a sludge treatment device or the like, if necessary, and subjected to processing such as recycling.

In the embodiment shown in FIG. 2, the pretreatment device 1
00 and the biological treatment apparatus 200, the sludge removal by the solid-liquid separation apparatus 400 is performed prior to the treatment by the physicochemical apparatus 300. Therefore, most of the solid pollutants are removed before the physicochemical treatment. It can be removed and the physicochemical treatment can be stabilized. Furthermore, by using the organic wastewater treatment apparatus 1 as described above, there is an advantage that more advanced treatment is possible.

FIG. 3 shows still another embodiment of the organic wastewater treatment apparatus 1 according to the present invention. In the wastewater treatment method shown in FIG. 3, the pretreatment device 100 removes contaminants or suspended substances (SS) contained in the organic wastewater. The organic wastewater that has undergone the pretreatment is sent to the physicochemical treatment apparatus 300. Here, organic matter, nitrogen, and phosphorus are removed by ultrasonic waves and electromagnetic waves. Then, biological treatment is performed by the biological treatment apparatus 200 to decompose organic substances in the organic wastewater. Further, in the subsequent step, the solid-liquid separation device 400 extracts the excess sludge, removes the remaining solid content, and regenerates it as treated water.

According to this embodiment of the organic wastewater treatment apparatus 1, the physicochemical treatment is performed before the biological treatment. As a result, the removal rate is low, the load flowing into the biological treatment apparatus 200, which generally requires a large aquarium, is reduced, the aquarium capacity used for biological treatment is reduced, and the use of expensive chemicals is reduced. This is advantageous in that the amount is reduced and the amount of sludge generated is also reduced. In the embodiment of the organic wastewater treatment apparatus 1 shown in FIG. 3, the cost can be most reduced among the embodiments of the present invention.

[0040]

The organic wastewater treatment apparatus 1 according to the present invention comprises:
According to the above-mentioned present invention, both biological treatment equipment utilizing the decomposition of organic matter by microorganisms, aggregate removal of organic matter, nitrogen, phosphorus, etc. by ultrasonic waves, etc., and physical oxidative decomposition of contained substances A physicochemical treatment device capable of Therefore, by using these different processing devices together, the respective processing capacities can be utilized, and the final T-N can be greatly reduced, and the devices can be managed by simple operation. Become. Furthermore, by incorporating physicochemical treatments with low running costs,
The biological treatment alone can reduce the running cost as compared with the advanced treatment.

[Brief description of drawings]

FIG. 1 is a diagram showing one form of an organic wastewater treatment apparatus according to the present invention.

FIG. 2 is a diagram showing another form of the organic wastewater treatment apparatus according to the present invention.

FIG. 3 is a diagram showing still another form of the organic wastewater treatment apparatus according to the present invention.

FIG. 4 is a diagram showing one form of a pretreatment apparatus used in the organic wastewater treatment apparatus according to the present invention.

FIG. 5 is a view showing a two-tank type device which is one form of a biochemical treatment device used in the organic wastewater treatment device according to the present invention.

FIG. 6 is a view showing a single tank type treatment device which is one form of a biochemical treatment device used in the organic wastewater treatment device according to the present invention.

[Explanation of symbols]

1 Organic wastewater treatment equipment 100 pretreatment equipment 110 residue removal device 120 Mechanical solid-liquid separator 130 Membrane separation device 200 Biological processor 210 Two-tank type processing equipment 211 Denitrification tank 212 Nitrification tank 220 Single tank type processing equipment 300 Physicochemical treatment equipment 400 Solid-liquid separation device

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C02F 9/00 C02F 9/00 502P 4D050 502Q 502Z 503 503C 504 504A 1/30 1/30 1/36 1 / 36 1/38 1/38 1/44 1/44 F 1/52 1/52 E 1/74 101 1/74 101 3/12 3/12 N 3/34 101 3/34 101B (72) Chief Inventor Katsumi, Nishiki-cho, Naka-ku, Yokohama-shi, Kanagawa Mitsubishi Heavy Industries, Ltd., Yokohama Works (72) Inventor, Tomoaki Omura 1-8, Koura, Kanazawa-ku, Yokohama-shi, Kanagawa Mitsubishi Heavy Industries, Ltd. Yokohama Research Institute F-term (reference) 4D006 GA06 GA07 KA01 KA02 KB03 KB13 KB20 KB21 PA01 PB08 4D015 BA23 BA24 BB01 FA01 FA12 FA26 4D028 BC01 BC17 BC18 4D037 AA11 AB02 AB04 BA16 BA26 BA28 CA03 CA04 CA06 CA07 4D040 BB05 BB07 BB12 BB14 BB22 BB24 BB22 BB52 BB54 BB57 BB65 4D050 BB01 BC01 BC02

Claims (9)

[Claims] 1. A pretreatment device for removing contaminants of organic wastewater, a biological treatment device for biologically treating the wastewater passed through the pretreatment device, and a wastewater passed through the biological treatment device. An organic wastewater treatment device comprising a physicochemical treatment device for physicochemical treatment. 2. The organic wastewater treatment device according to claim 1, further comprising a solid-liquid separation device that removes solids of wastewater that has passed through the biological treatment device, before the physicochemical treatment device. 3. A pretreatment device for removing impurities of organic wastewater, a physicochemical treatment device for physicochemically treating the wastewater passed through the pretreatment device, and a wastewater passed through the physicochemical treatment device. And a biological treatment device for biologically treating the organic wastewater treatment device. 4. The organic wastewater treatment device according to claim 3, further comprising a solid-liquid separation device that removes solid components of the wastewater that has passed through the biological treatment device. 5. The organic treatment apparatus according to claim 1, wherein the biological treatment apparatus is a wet oxidation apparatus, an aerobic digestion apparatus, or an apparatus combining both of them. Wastewater treatment equipment. 6. The biological treatment apparatus is a nitrification and denitrification apparatus that utilizes microorganisms.
4. The organic wastewater treatment device according to any one of 4 above. 7. The organic wastewater treatment apparatus according to claim 1, wherein the physicochemical treatment apparatus uses ultrasonic waves, electromagnetic waves, or both of them. 8. The solid-liquid separation device is any one of a gravity settling device, a membrane separation device, a centrifugal concentrating device, or a device in which two or more of them are combined together. Item 8. The organic wastewater treatment device according to any one of Items 4 to 7. 9. An organic wastewater treatment method using the apparatus according to claim 1.