JPH08215694A - Highly functional biological treatment apparatus - Google Patents

Abstract

PURPOSE: To efficiently treat highly conc. waste water and to ensure a space for high-order treatment by connecting a three-phase fluidized tank housing fluidized carriers to receive waste water to a sedimentation tank through an activated sludge tank or directly to eliminate the bulking of the sedimentation tank. CONSTITUTION: A three-phase fluidized tank A is connected to an aeration tank B through a partition wall 8 and the upper edge of the partition wall 8 is formed into an overflow weir 9 and a carrier accumulation preventing means 10 such as an inclined plate is formed to the corner part of the bottom part of the partition wall 8. Further, three-phase rising and falling areas (a), (b) are formed to a fluidized bed part by aeration from an air pipe 5 to form circulating flow. In this circulating process, a suspended substance is purified by the oxidizing action of bacteria fixed to carriers and treated water passing through a carrier sedimenting area (c) and a water passing area (d) is introduced into the aeration tank 8 through the overflow weir 9 and treated as revolving streams by aeration to be sent to a sedimentation tank C from a trough 20. By this constitution, the bulking of the sedimentation tank C is eliminated to efficiently treat highly conc. waste water and a space for high-order treatment is ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION This invention is based on the activated sludge method.
The present invention relates to a highly functional biological treatment device capable of significantly reducing the equipment area when treating domestic wastewater or factory wastewater.

[0002]

2. Description of the Related Art Conventional biological wastewater treatment methods include an activated sludge method, a batch method which can be said to be an activated sludge modification method of intermittently inflowing raw water, discharging treated water and aeration, and a fixed filter bed in liquid. The contact aeration method of immersing in is typical. These methods generally increase the amount of microorganisms in the biological treatment tank to increase the biological treatment efficiency by increasing the amount of returned sludge in the activated sludge method and decreasing the amount of drawn-out sludge in the batch method. However, bulking that prevents the precipitation and separation of SS occurs in the settling tank that separates SS from the treated water, so there is a limit to increasing the amount of microorganisms MLSS in the biological treatment tank. Also, in the contact aeration method, a filter medium with a narrow contact material interval is effective for increasing the amount of microorganisms, but a contact material with a narrower interval will impair the circulation contact of microbial treated water and reduce the biological treatment efficiency. There is. In the conventional biological treatment method, the amount of MLSS that can be retained in the treatment tank is limited, and the amount of removed pollutants (removed volume load) in the wastewater per unit volume of the biological treatment tank is small. Was designed in a rectangular shape and had a large volume, with a large footprint and enormous construction cost.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides a wastewater treatment apparatus which can increase the concentration of microorganisms in a biological treatment tank, reduce the effective volume of the tank, and narrow the entire apparatus. Further, the present invention provides an apparatus capable of utilizing existing equipment without requiring new equipment for carrying out the present invention, and an apparatus capable of making a surplus space a high-level processing space.

[0004]

According to the present invention, a microorganism-immobilized carrier is suspended and suspended in wastewater to be treated, and aeration is supplied from the bottom of the tank so that the activated sludge grows in the tank and a complete mixed flow is formed. A three-phase fluidization device that can mix the required amount of returned sludge with the wastewater supplied as needed to maintain a high concentration of microorganisms in the tank is directly connected to the aeration tank, or an aeration tank with a relatively small volume can be used. It is a high-performance processing device that can be connected to a settling tank to obtain treated water. The three-phase fluidization device in the present invention is a carrier sedimentation guide area above a carrier outflow prevention / accumulation prevention inclined plate provided at an angle of 30 ° or more on the rear wall from the bottom of a tank filled with a fluid carrier and equipped with aeration means. A fluidized bed section and a carrier separation section are configured in the tank by a vertical separation plate projecting above the water surface through one side, and one or more draft plates are vertically installed in the water area of the fluidized bed section to circulate and flow the carrier. An ascending zone and a descending zone are formed, and a wake prevention plate for preventing the outflow of the carrier is vertically provided above the inclined plate in the carrier separating part, and overflows the upper edge of the rear wall. This is a weir, and normally the activated sludge is returned from the settling tank, but depending on the post-stage equipment such as high-level treatment, the sludge may not be returned. The settling tank is not an essential device. For example, when the pollutant concentration of raw water is low and the aeration tank is a contact aeration tank, SS may be captured by the filter material of the aeration tank, and thus the precipitation tank may be unnecessary. By providing an overflow water trough in place of the overflow weir on the upper edge of the rear wall, the outflow direction of the treated water can be changed and the tanks can be connected in parallel. Further, when the tanks are connected in multiple stages in series, a carrier backflow prevention plate is provided in the latter tank. The fluid carrier used in the present invention is not only a conventionally used carrier such as activated carbon fine powder or an inorganic carrier such as cement but also a granulated product (particle size 5 to 15 mm) of completely saponified polyvinyl alcohol or a fine powder on the surface of the granule. A microorganism-immobilized support (Japanese Patent Publication No. 21317/1990) coated with 0.5 to 3 parts of activated carbon is preferable. The filling amount in the tank can be 5 to 60 parts by volume or more with respect to the tank volume.

[0005]

[Embodiment 1] FIGS. 1 and 2 show an apparatus in which a three-phase flow tank is connected to a settling tank through an aeration tank and sludge is returned to the three-phase flow tank. A tank, B is an aeration tank, and C is a precipitation tank for separating and collecting SS. Reference numeral 1 is a wastewater raw water introduction pipe, 2 is a drainage measuring tank, 3 is a distribution tank, 4 is a return sludge return pipe, and 5 is an air supply pipe. The configurations of the aeration tank B and the precipitation tank C are the same as those of the conventional activated sludge method device. The three-phase flow tank A is connected to the aeration tank B by a rear wall or a partition wall 8, and the upper edge of the partition wall is an overflow weir 9. 1
Reference numeral 0 is a carrier deposition preventing means such as an inclined plate provided at an angle of about 50 ° at the bottom corner of the partition wall. 11 is vertically fixed above the inclined plate so that the fluidized bed section 12 and the carrier settling section 1 are provided in the tank.
3 is a separation plate, 14 is a draft plate provided in the flowing water region, and 15 is a wake prevention plate that serves as a guide for the sedimentation of the carrier and also as an outflow prevention. The tank is filled with a required amount of a microorganism-immobilized carrier (not shown), and by aeration from the air tube 5, a three-phase rising region a and a three-phase falling region b are formed in the fluidized bed to form a circulating flow. In this circulation process, pollutants are purified by the oxidizing action of the microorganisms immobilized on the carrier, and the treated water that has passed through the carrier sedimentation area c and water passage area d is introduced into the aeration tank B through the overflow weir 9 and aerated. Is processed into a swirling flow by the above and is sent from the trough 20 to the settling tank C. According to this device,
Even if wastewater of the same water quality was treated with a device without a three-phase flow tank, bulking did not occur in the settling tank and operation management was easy.

[0006]

[Example 2] Conventional apparatus (biological treatment tank by activated sludge method,
Volume 100 m ^3), the mixed waste water canteen wastewater 48m ³ / D and cosmetic process wastewater ^{7m 3 / D 55m 3 / D} (BOD12
(50 mg / L, COD 450 mg / L) was introduced under the design conditions as shown in Table 1 in order to reduce the treated water BOD to 10 mg / L or less and COD 60 mg / L or less. Due to the large fluctuation range, bulking often occurred and it was practically impossible to process. To avoid this trouble, process wastewater of 7 m ³ /
Excluding D, BOD volume load 0.09 kg / m ³ · D,
It was operating with an SS load of 0.03 kg / m ³ · D.

[0007]

[Table 1]

In Table 1, the raw water load is BOD, C
The pollutant load obtained by multiplying the concentration of each OD by the amount of water and the amount of treated water removed are the values obtained by subtracting the remaining amount of pollutant obtained by multiplying the concentration of treated water by the amount of water from the pollutant load of raw water, and the removal rate. Is the percentage of the amount removed to the pollution load. The AS treatment condition is an activated sludge treatment condition, and the volume load of the AS treatment condition indicates the amount required per day per unit volume of the activated sludge tank. In this case, the pollution load amount of the raw water is 100 m ^{3 of the} activated sludge tank volume.
It is the number divided by. HRT is the time during which the water to be treated stays in the activated sludge tank, and is calculated by dividing the volume of the activated sludge tank by the amount of water corrected per hour. In addition, the SS load used in the case of the activated sludge method is a value obtained by dividing the pollution load of raw water by the activated sludge amount MLSS in the activated sludge tank or aeration tank. The smaller these values, the more stable biological treatment is possible. Become.

FIG. 3 shows a conventional existing activated sludge tank (volume 100
m ³ ), three-phase flow tanks are installed in parallel in the m ³ ), and three-phase flow tanks A 1 and A 2 of the same structure are arranged side by side and partitioned by partition walls 18 to form a fluidized bed portion of A 1 and A 2. 12m total volume
The volume of ³ and B is 75 m ³ . The improved device to process the waste water 10 m ³ / D was mixed total volume 58m ³ /
D, BOD 2000 mg / L and COD 800 mg / L were operated under the treatment conditions shown in Table 2. Treated water BOD is 10m
g / L or less, COD was 60 mg / L or less, and no bulking occurred in the precipitation tank during operation.

[0010]

[Table 2]

Raw water in Table 2 is the drainage water of the cafeteria 48 m ³ /
D, process wastewater 10 m ³ / D mixed wastewater. Treated water / AS raw water is the specifications of treated water treated in a three-phase fluidized bed, and this indicates that it becomes raw water for the activated sludge tank in the latter stage.
The pretreatment condition is the treatment condition of the three-phase fluidized bed, and the AS treatment condition is the activated sludge treatment condition of which the treated water of the three-phase fluidized bed is the raw water. HRT in the pretreatment condition is the residence time in the three-phase fluidized bed, and the load is the volume of the raw water divided by the volume of the three-phase fluidized bed, and the load of the carrier is the volume of the carrier. It is the number divided by. The AS treatment conditions and the specifications of the treated water are the same as in Table 1.

In the present invention, the structure of the three-phase flow tank A is not limited to the structure shown in FIG. 1 and FIG.
The above-mentioned carrier accumulation preventing means 16 is provided in a protruding manner, and the aeration means 5a and a plurality of draft plates 14 are symmetrically arranged in parallel with each other so as to form two or more ascending regions a and descending regions b in the fluidized bed. You may do it.

[0013]

[Embodiment 3] In the apparatus shown in FIG. 5, three three-phase flow tanks A1, A2 and A3 having the same structure according to FIG. 4 are connected in series and the overflow water of the final-stage tank A3 is directly introduced into the precipitation tank C. This is the device. In the figure, the structures of the aeration pipe and the tank are omitted. Reference numeral 17 is a backflow prevention plate that prevents the carrier from flowing back from the subsequent flow tank. Total volume of three-phase fluidized tank 200
m ^3, microbe immobilizing carrier filling the (average particle size 6 mm) 20 parts by volume of BOD3000mg / L chemical industrial wastewater 1
The result of supplying at 200 m ³ / D is shown in Table 3,
The treated water BOD could be 600 mg / L.

[0014]

[Table 3]

Table 3 shows an example of a three-phase flow tank in which three tanks are connected in series. The treated water BOD is a numerical value indicating the specifications of overflow water in each room. The treatment conditions are calculated in the same manner as the pretreatment conditions in Table 2. The removal efficiency is a value obtained by dividing the removal amount described in the column of treated water BOD by the volume of the three-phase fluidized bed and the volume of the carrier.

By the way, the volume of the conventional biological treatment tank in which the same wastewater to be treated is treated by the immersion filter contact aeration method is as follows:
1000 m ³ (first chamber 600 m ³ , second chamber 400 m ³ ), which is 5 times that of the apparatus of the above-mentioned example, and 600 volcanic gravel (average particle size 100 mm, gravel layer porosity 50%) was used as a filter medium.
It was filled with m ³ (60 parts by volume) and operated under the conditions shown in Table 4, and only treated water having a BOD of 900 mg / L was obtained.

[0017]

[Table 4]

Generally, many kinds of organic pollutant chemical species are contained in the wastewater of a chemical factory, and it is usual that they are biologically treated sequentially. Therefore, a plurality of three-phase flow tanks should be connected in series. By this, microorganisms working on the target chemical species can be segregated and the treatment efficiency can be improved. Further, when the amount of water to be treated is large and the biological treatment is carried out by the zero-order reaction, the parallel connection as shown in FIG. 6 is effective.

[0019]

[Effect] According to the apparatus of the present invention, the space required for obtaining treated water of the same quality except for the precipitation tank can be narrowed to about 10 to 20%, and bulking does not occur in the precipitation tank, so that operation management is possible. It will be easier. Further, since the amount of air required for aeration can be reduced to about 1/5, the processing cost can be reduced.

[Brief description of drawings]

FIG. 1 is a vertical sectional side view of the entire device of the present invention.

FIG. 2 is a plan view of an essential part of FIG.

FIG. 3 is a plan view in which a three-layer fluidized tank is installed in parallel with activated sludge.

FIG. 4 is a side view in which three-layer flow tanks are provided in multiple stages in series.

FIG. 5 is a cross-sectional view of a main part of a large three-layer flow tank.

FIG. 6 is a plan view when the partitioned three-layer flow tanks are arranged in parallel.

[Explanation of symbols]

 A three-phase fluidized tank B activated sludge tank or aeration tank C settling tank 1 drainage line 4 sludge return pipe 5 air supply pipe 6 tank bottom 8 partition wall 9 overflow weir 10 carrier accumulation prevention plate 11 separation plate 12 fluidized bed part 13 carrier Settling part 14 Draft plate 15 Carrier wake prevention plate 20 Overflow water trough

[Procedure amendment]

[Submission date] March 16, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Claims

[Correction method] Change

[Correction content]

[Claims]

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Change

[Correction content]

[0002]

2. Description of the Related Art Conventional biological wastewater treatment methods include an activated sludge method, a batch method which can be said to be an activated sludge modification method of intermittently inflowing raw water, discharging treated water and aeration, and a fixed filter bed in liquid. The contact aeration method of immersing in is typical, and each is composed of an aeration tank and a precipitation tank. These methods generally increase the amount of microorganisms in the biological treatment tank to increase the biological treatment efficiency by increasing the amount of returned sludge in the activated sludge method and decreasing the amount of drawn-out sludge in the batch method. However, in the settling tank that separates SS from the treated water,
Since bulking occurs that prevents the precipitation and separation of S, there is a limit to increasing the amount of microorganisms MLSS in the biological treatment tank. In addition, in the contact aeration method, a filter medium with a narrow contact material interval is effective for increasing the amount of microorganisms, but a contact material with a narrower contact interval is more limited because it deteriorates the circulation contact of microbial treated water and lowers the biological treatment efficiency. There is. With conventional biological treatment methods, the amount of MLSS that can be retained in the treatment tank is limited, and the amount of pollutant removed (removed volume load) in the wastewater per unit volume of the biological treatment tank is small. Was designed in a rectangular shape and had a large volume, with a large footprint and enormous construction cost.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction content]

[0004]

According to the present invention, a microorganism-immobilized carrier is suspended and suspended in wastewater to be treated, and aeration is supplied from the bottom of the tank so that the activated sludge grows in the tank and a complete mixed flow is formed. A three-phase fluidizer that can mix the required amount of returned sludge with the wastewater to be supplied as needed to maintain a high concentration of microorganisms in the tank was directly connected to the aeration tank or installed in the existing aeration tank. The device is a high-performance treatment device capable of obtaining treated water by connecting to a settling tank through an aeration tank having a relatively small volume as compared with conventional devices. Furthermore, the three-phase fluidizer is a device that can directly connect to the settling tank without interposing an aeration tank to achieve advanced treatment. The three-phase fluidization device in the present invention is a carrier sedimentation guide area above a carrier outflow prevention / accumulation prevention inclined plate provided at an angle of 30 ° or more on the rear wall from the bottom of a tank filled with a fluid carrier and equipped with aeration means. A fluidized bed section and a carrier separation section are configured in the tank by a vertical separation plate projecting above the water surface through one side, and one or more draft plates are vertically installed in the water area of the fluidized bed section to circulate and flow the carrier. An ascending zone and a descending zone are formed, and a wake prevention plate for preventing the outflow of the carrier is vertically provided above the inclined plate in the carrier separating part, and overflows the upper edge of the rear wall. This is a weir, and normally the activated sludge is returned from the settling tank, but depending on the post-stage equipment such as high-level treatment, the sludge may not be returned. Further, in the present invention, the precipitation tank can be eliminated.
For example, when the pollutant concentration of raw water is low and the aeration tank is a contact aeration tank, SS may be captured by the filter material of the aeration tank, and thus the precipitation tank may be unnecessary. By providing an overflow water trough in place of the overflow weir on the upper edge of the rear wall, the outflow direction of the treated water can be changed and the tanks can be connected in parallel. Further, when the tanks are connected in multiple stages in series, a carrier backflow prevention plate is provided in the latter tank. The fluid carrier used in the present invention is a conventionally used carrier such as an activated carbon fine powder or an inorganic carrier such as cement, and in particular, a granulated product of completely saponified polyvinyl alcohol (particle size 1 to 15 mm, preferably 5
mm or more) or 0.5 to 3 finely powdered activated carbon on the surface of the granules
A microorganism-immobilized carrier (Japanese Patent Publication No. 21317/1990) coated with a part added thereto is suitable. The filling amount in the tank can be 5 to 60 parts by volume or more with respect to the tank volume.

[Procedure amendment 4]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 3

[Correction method] Change

[Correction content]

FIG. 3 is a plan view in which a three-phase flow tank is installed in parallel with activated sludge.

[Procedure Amendment 5]

[Document name to be amended] Statement

[Name of item to be corrected] Fig. 4

[Correction method] Change

[Correction content]

FIG. 4 is a sectional view of a main part of a large three-phase flow tank.

[Procedure correction 6]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 5

[Correction method] Change

[Correction content]

FIG. 5 is a side view in which a three-phase flow tank connected in series is directly connected to a precipitation tank.

[Procedure Amendment 7]

[Document name to be amended] Statement

[Name of item to be corrected] Figure 6

[Correction method] Change

[Correction content]

FIG. 6 is a plan view when three-phase flow tanks are arranged in parallel.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Keiji Taniguchi 2-16-3 Hatchobori, Chuo-ku, Tokyo Denka Engineering Co., Ltd. (72) Inventor Shuzo Fujii 2-3-16 Hatchobori, Chuo-ku, Tokyo Denka Engineering Co., Ltd.

Claims (6)

[Claims] 1. A biological treatment tank for waste water is composed of only a three-phase flow tank, and the three-phase flow tank has a carrier deposition prevention plate inclined to a rear wall thereof and a separation plate vertically installed above the plate. A fluidized bed portion and a carrier sedimentation area are formed by the aeration means provided in the fluidized bed bottom portion and a wake prevention plate provided in the carrier sedimentation area, and further, a fluidized carrier is filled in the tank for drainage. Biological treatment equipment. 2. A three-phase flow tank to which waste water to be treated is supplied and an aeration tank, and the three-phase flow tank is provided with a carrier deposition prevention plate inclined on a rear wall thereof and vertically suspended above the plate. The separation plate forms a fluidized bed portion and a carrier sedimentation area, an aeration means is provided at the bottom of the fluidized bed, a wake prevention plate is provided in the carrier sedimentation area, and a fluidized carrier is filled in the tank. Wastewater biological treatment equipment. 3. The biological treatment apparatus according to claim 2, wherein a sludge separation settling tank is provided after the aeration tank, and a part or all of the separated sludge is returned to the three-phase flow tank. 4. The biological treatment apparatus according to claim 1, wherein a plurality of three-phase flow tanks are connected in parallel to the waste water introduction pipe. 5. The biological treatment apparatus according to claim 1, wherein a plurality of three-phase flow tanks are connected in series. 6. The carrier filled in the three-phase fluidized tank is a granular carrier of completely saponified polyvinyl alcohol having a particle size of 1 to 15 mm or a carrier obtained by coating the surface of the granular carrier with fine powder of activated carbon. Item 6. The biological treatment device according to any one of items 5.