WO2021033369A1 - Treatment equipment for sludge effluent and treatment method for same - Google Patents

Abstract

This invention includes: a first step for performing aerobic bacterial treatment in which sludge effluent containing organic sludge is introduced into an aeration tank 13, and enzymes for promoting decomposition of organic sludge and wood powder, which is capable of supporting aerobic bacteria for decomposing organic sludge and has a particle size of 1 mm or less, are supplied into the aeration tank 13 to perform aeration; a second step for introducing the sludge effluent treated in the first step into a sedimentation tank 15 so as to separate the same into sediment and treated water; and a third step for introducing the sediment generated in the second step into a regeneration tank 16 and performing aeration treatment. The treated material treated in the third step is supplied to the aeration tank 13 and the wood powder is recirculated for use.

Description

Sludge wastewater treatment equipment and its treatment method

The present invention relates to the treatment of sludge wastewater (including sewage) having a high BOD (biochemical oxygen demand), and particularly relates to a sludge wastewater treatment facility using an aeration tank in which an enzyme is used and a treatment method thereof.

Conventionally, various treatment facilities and treatment methods for sludge wastewater containing organic sludge, which are discharged from general households, office buildings, various factories, etc., have been proposed.
For example, Patent Document 1 includes an aeration tank for receiving and treating sludge wastewater, a first settling tank for receiving treated sludge wastewater, and a large number of carriers for retaining microorganisms, and the treated water in the first settling tank is provided. A carrier fluidized tank that receives and aerates, a second settling tank that receives the treated water treated in the carrier fluidized tank, and a sludge recycling tank that accepts and aerates the sediment accumulated in the first and second settling tanks. The treatment equipment and treatment method of sludge wastewater having the above are disclosed.

Japanese Patent No. 5925023 Japanese Unexamined Patent Publication No. 2000-024628 Japanese Unexamined Patent Publication No. 2006-326386

Generally, a resin (plastic) carrier having a large number of micropores can be used as a carrier for retaining microorganisms, but a large number of resins are used because the carriers repeatedly collide with each other during aeration treatment of sludge wastewater. It was easy for powder to be generated.
Therefore, when the treated water treated by the treatment facility is discharged to a river, the sea, or the like, the above-mentioned resin powder is also discharged together with the treated water, which may affect the environment.
Patent Document 1 does not specifically describe what is used as the carrier for retaining microorganisms, but describes that the particle size of the carrier for retaining microorganisms is about 2 to 10 mm.
Further, in Patent Documents 2 and 3, cellulose fibers, wood pieces, bamboo pieces, carbides thereof, wood chips and the like are used as a carrier (base material) for holding microorganisms that decompose organic sludge. The width is about 10 mm in length and width, and the thickness is about 2 to 5 mm.
As described above, when the size of the microbial carrier is large (more than 1 mm), buoyancy acts to float on the water surface, making it difficult to stir, and it becomes impossible to efficiently decompose organic sludge.

The present invention has been made in view of such circumstances, and is a sludge wastewater that can be treated efficiently to the extent that sludge wastewater containing organic substances can be discharged to rivers and the sea while reducing and preventing the environmental load as compared with the conventional case. An object of the present invention is to provide a processing facility and a processing method thereof.

The sludge wastewater treatment facility according to the present invention according to the above object receives an aeration tank that receives sludge wastewater containing organic sludge and aerates the sludge wastewater, and a sludge wastewater that has been aerated by the aeration tank, and receives the sludge. A settling tank that separates wastewater into sediment and treated water, a regenerating tank that receives the settling accumulated in the settling tank and further aerates the sediment, and an aeration tank that treats the treated material in the reclaimed tank. In a sludge wastewater treatment facility that has a circulation channel to supply to
In the aeration tank, an enzyme that promotes the decomposition of the organic sludge and a wood powder having a particle size of 1 mm or less that serves as a carrier of aerobic bacteria that decompose the organic sludge are used.
Here, the wood powder can contain the enzyme.

It is possible to supply a new wood powder to the aeration tank to compensate for the shortage of the supply amount of the wood powder to be recycled to the aeration tank.
In addition, a new enzyme that makes up for the shortage of the supply amount of the enzyme used in circulation to the aeration tank can be supplied to the aeration tank.

The sludge wastewater treatment method according to the present invention according to the above object can put sludge wastewater containing organic sludge into an aeration tank and carry an enzyme that promotes decomposition of the organic sludge and an aerobic bacterium that decomposes the organic sludge. The first step of supplying a wood powder having a particle size of 1 mm or less to the aeration tank and aerating it to treat aerobic bacteria,
The second step of putting the sludge wastewater treated in the first step into a settling tank and separating it into a sediment and treated water, and
It has a third step of putting the precipitate generated in the second step into a regeneration tank and performing aeration treatment.
The processed product treated in the third step is supplied to the aeration tank, and the wood powder is circulated and used.
Here, the wood powder can contain the enzyme.

When the supply amount of the wood powder used for circulation to the aeration tank is insufficient, new wood powder can be supplied to the aeration tank.
Further, when the supply amount of the enzyme used for circulation to the aeration tank is insufficient, a new enzyme can be supplied to the aeration tank.

In the sludge wastewater treatment equipment and the treatment method thereof according to the present invention, since aerobic bacteria that decompose organic sludge are carried on wood powder, it is not necessary to use a resin carrier as in the conventional case.
Further, since the processed product treated in the regeneration tank is supplied to the aeration tank, wood powder and enzymes can be circulated and used, and further, enzymes produced by aerobic bacteria and enzymes of dead aerobic bacteria themselves can be used.
Therefore, sludge wastewater containing organic matter can be treated to the extent that it can be discharged to rivers and the sea while reducing and preventing the environmental load as compared with the conventional case.
Then, since the wood powder having a particle size of 1 mm or less settles without floating when supplied to water, it is easily mixed with the organic sludge, and the organic sludge can be efficiently decomposed by aerobic bacteria.

It is explanatory drawing of the sludge wastewater treatment equipment and the treatment method thereof which concerns on one Example of this invention.

Subsequently, an embodiment embodying the present invention will be described with reference to the attached drawings, and the present invention will be understood.
As shown in FIG. 1, the sludge wastewater treatment equipment 10 according to the embodiment of the present invention includes a raw water tank 11, a flow rate adjusting tank 12, first and second aeration tanks 13, 14, a settling tank 15, and a regeneration tank. It is a facility that has 16, a discharge tank 17, and a circulation passage 18, and can treat sludge wastewater containing organic matter to the extent that it can be drained to rivers and the sea while reducing and preventing the environmental load as compared with the conventional one. The details will be described below.

The raw water tank 11 is a tank that receives sludge wastewater (also simply referred to as “drainage” or “raw water”) to be treated, which contains organic sludge. The sludge drainage has an activated sludge suspended matter concentration (MLSS) of, for example, 3000 to 6000 mg / L.
The raw water tank 11 is provided with an air diffuser 20 for ejecting compressed air sent from the aeration blower 19, and has a structure capable of stirring the internal wastewater.

The sludge wastewater that has been agitated in the raw water tank 11 is supplied to the flow rate adjusting tank 12 via the screen means 21.
The screen means 21 has a net having an opening (opening) of, for example, 1 mm (may be about 1 to 10 mm), and removes dust exceeding 1 mm from the wastewater pumped from the raw water tank 11 by the pump 22. It is a thing. The opening of the screen means can be variously changed according to the size of the waste contained in the sludge wastewater to be treated.

The flow rate adjusting tank 12 is a tank for storing sludge wastewater from which dust has been removed by the screen means 21.
The sludge drainage stored in the flow rate adjusting tank 12 is pumped up by the pump 23 and supplied to the first aeration tank 13 via the measuring tank 24. The measuring tank 24 is a tank capable of controlling the amount of drainage passing through to a constant amount and returning excess drainage to the flow rate adjusting tank 12, and for example, the measuring tank described in Patent Document 1 can be used. However, the configuration is not particularly limited as long as the supply amount of sludge wastewater can be adjusted.

The first and second aeration tanks 13 and 14 are arranged in series to aerate the sludge wastewater received from the flow rate adjusting tank 12. The first and second aeration tanks 13 and 14 can be continuously operated by constantly adding sludge drainage little by little while adjusting the flow rate in the measuring tank 24. In this case, from the first aeration tank 13. The overflowed sludge drainage flows into the second aeration tank 14.
The first and second aeration tanks 13 and 14 are provided with aeration means 25 and 26 for ejecting compressed air supplied from the aeration blower 19, respectively, and air (oxygen) is supplied to the sludge drainage containing organic substances supplied to the inside. ) Is sent and the inside is agitated (that is, aeration treatment), and the organic substances contained in the wastewater are eaten and decomposed by aerobic bacteria (an example of aerobic bacteria) which are microorganisms contained in the wastewater (that is, aerobic bacteria). It has become aerobic bacteria treatment).

The first and second aeration tanks 13 and 14 (either one of them may be used) are provided with an enzyme addition means 27 for supplying an enzyme.
Enzymes digest organic matter contained in sludge wastewater into low-molecular-weight compounds and promote the decomposition of organic matter by aerobic bacteria. That is, the treatment of sludge wastewater by aerobic bacteria (decomposition of organic matter) takes time, but by adding an enzyme, the organic matter is reduced in molecular weight and easily decomposed by aerobic bacteria, further promoting the activity of aerobic bacteria. It can be done and the processing time can be shortened. These aerobic bacteria also produce enzymes through their activities, helping to break down organic sludge. A part of the enzyme remains in the treated water.

Here, since two aeration tanks are arranged in series, the organic matter decomposition treatment by aerobic bacteria is more complete. For example, the amount of sludge wastewater to be treated, the concentration of activated sludge suspended matter, and the scale (volume) of the aeration tank ) Etc., one unit may be used, or a plurality of three or more units may be arranged in series, or two or more aeration tanks may be arranged in parallel.
Types of enzymes include, for example, oil-degrading enzymes (eg, lipase), proteolytic enzymes (eg, proteases), starch-degrading enzymes (eg, amylase), plant fiber-degrading enzymes (eg, pectinase), polysaccharide-degrading enzymes. (Hemicellulase) and the like, and it is preferable that one or two or more of these are the main components. The amount of the enzyme is preferably, for example, about 1/10000 to 1/10000 with respect to the amount of wastewater, but is not particularly limited, and for example, activated sludge suspended matter when discharged into a river or the sea. Various changes can be made according to the concentration, BOD, and the like.

Further, the first aeration tank 13 (and / or the second aeration tank 14) is provided with a wood powder adding means 28 for supplying wood powder.
The wood powder carries aerobic bacteria contained in sludge wastewater (becomes a habitat (carrier) for aerobic bacteria) and has decay resistance to these aerobic bacteria. Here, the decay resistance means that the decomposition rate of wood powder by aerobic bacteria is slower than the decomposition rate of organic matter in sludge wastewater. As described above, the types of wood powder having decay resistance include, for example, Sugi, Hinoki, Hiba, Karamatsu, Beihi, Baisugi, Beimatsu, Keyaki, Quercus acutissima, Chestnut, Teak, Pinkado, Melbau, Ipe, etc. 1 or 2 or more of the above can be used, but sugi is particularly preferable.
As the wood powder, one containing the above-mentioned enzyme (one impregnated with the enzyme) can be used. In this case, the enzyme adding means 27 described above may or may not be present.

The size of this wood powder may be any powder that is fine enough to settle without floating when supplied to water, and is 1 mm or less (preferably 0.5 mm or less, more preferably 0.5 mm or less, depending on the type of wood or the like. It is preferably about 0.2 mm or less, and the lower limit is not particularly limited, but for example, about 0.01 mm (preferably 0.03 mm) can be used. By using a wood powder of 1 mm or less that settles without floating when supplied to water, it is sufficient that the wood powder can be easily mixed with organic sludge, and the wood powder contains more than 1 mm. It doesn't matter if you have it.
It is preferable to add the wood powder to the wastewater in a state where the wood powder is put into water in advance and stirred to absorb the water, but the wood powder can be added to the sludge drainage as it is. it can. For example, about 50 to 100 L of water (wood powder concentration: about 1 to 20% by mass, further the lower limit is about 3% by mass) in which wood powder is mixed with ^{1 m 3} of sludge drainage having a BOD of about 1000 mg / L. , The upper limit is about 15% by mass), but is not particularly limited, and can be variously changed depending on, for example, the concentration of suspended sludge suspended when discharged into a river or the sea, BOD, and the like.

The settling tank 15 receives sludge drainage overflowing from the second aeration tank 14, that is, sludge drainage that has been aerated and treated with aerobic bacteria by a natural flow, and sludge (sediment) and supernatant liquid (treated water). It is a tank that separates into.
If the settling tank 15 containing the sludge drainage is left unstirred, the sludge will settle on the bottom and be separated into the non-sedimentary supernatant liquid and the settling sludge. Therefore, the settling tank 15 tends to collect sludge on the bottom. A conical portion 29 whose diameter gradually decreases downward is provided in the lower portion, and a cylindrical portion 30 is formed on the conical portion 29.
The settling tank 15 has a (air lift) pump 31 at its axial position. The pump 31 carries the sludge sucked from the bottom by an air blow upward and separates the sludge from the air.

The sludge settled in the settling tank 15 is extracted by the pump 31 and sent to the reclaiming tank 16 via the sludge measuring tank 32. The sludge measuring tank 32 can measure the amount of sludge passing through, and for example, the sludge measuring tank described in Patent Document 1 can be used, but the sludge measuring tank 32 is not limited to this.
On the other hand, the supernatant separated in the settling tank 15 is stored in the discharge tank 17 and periodically discharged to the outside of the system (sewage or river). This supernatant has, for example, an activated sludge suspended matter concentration of 250 mg / L or less and a BOD of 160 mg / L or less (more specifically, 10 to 50 mg / L), and is in a state where water can be discharged to the outside. ..

The regeneration tank 16 is a tank that receives the sludge accumulated in the settling tank 15 and further aerates the sludge.
Since the regeneration tank 16 has an air diffuser 33 and blows (bubbling) the compressed air generated by the aeration blower 19 into the tank, aerobic bacteria further act on it to generate organic sludge. Disassembly can proceed.
The treatment of the regeneration tank 16 is performed by a batch treatment, and after aeration treatment with air for a certain period of time, the aeration by the air diffuser 33 is stopped, and the sludge (processed material) inside is held in a stationary state. The sludge includes enzymes remaining in the first aeration tank 13 (hereinafter, also referred to as residual enzymes) and wood powder, and aerobic bacteria (living and dead) contained in the sludge wastewater. It contains enzymes produced by aerobic bacteria.

The circulation path 18 is a pipe that supplies the sludge (treated product) treated in the regeneration tank 16 to the first aeration tank 13. Specifically, the sludge in the regeneration tank 16 is extracted by the pump 34 and sent to the first aeration tank 13 via the sludge measuring tank 35 provided in the circulation path 18.
Here, wood powder, residual enzymes, enzymes produced by aerobic bacteria, and enzymes of dead aerobic bacteria themselves (hereinafter, also referred to as enzymes derived from aerobic bacteria) are circulated and used.
Therefore, the enzyme supplied to the first aeration tank 13 by the enzyme adding means 27 and flowing out together with the above-mentioned supernatant is supplemented with the enzyme derived from aerobic bacteria and the residual enzyme, and the wood powder adding means 28 is used to make the second. Since the wood powder supplied to the aeration tank 13 of 1 has decay resistance, it remains without being consumed, so that the amount of new enzyme and / or wood powder added to the first aeration tank 13 can be reduced. ..

When the amount of the above-mentioned enzyme used for circulation to the first aeration tank 13 is insufficient, for example, when the amount of the enzyme contained in the supernatant separated in the settling tank 15 is large, or aerobic bacteria When the amount of the derived enzyme is small, a new enzyme that makes up for the shortage of the supply amount can be supplied to the first aeration tank 13 by the enzyme addition means 27 (when the wood powder contains the enzyme, wood). The shortfall may be supplemented by adding powder).
Further, when the supply amount of the above-mentioned recycled wood powder to the first aeration tank 13 is insufficient, for example, when the wood powder is decomposed by aerobic bacteria, a new method of compensating for the shortage of the supply amount. The wood powder can be supplied to the first aeration tank 13 by the wood powder adding means 28.

As described above, sludge drainage is supplied to the first aeration tank 13 at a predetermined flow rate via the flow rate adjusting tank 12, and sludge is supplied from the settling tank 15 to the regeneration tank 16 via the sludge measuring tank 32. Further, by supplying sludge of a predetermined flow rate from the regeneration tank 16 to the first aeration tank 13 via the sludge measuring tank 35, the processing amount of each device can be limited and an overload can be applied. It is possible to treat sludge wastewater reliably.

Subsequently, a sludge wastewater treatment method according to an embodiment of the present invention will be described with reference to FIG.
(Preparation process)
First, sludge wastewater containing organic sludge is received in the raw water tank 11 and agitated by the air diffuser 20.
This sludge wastewater has an activated sludge suspended matter concentration (MLSS) of, for example, 3000 to 6000 mg / L. If the MLSS concentration is less than 3000 mg / L, the amount of organic matter is small and the purification action does not proceed smoothly, and if the MLSS concentration exceeds 6000 mg / L, precipitation separation in the settling tank 15 cannot be performed efficiently.
Next, the sludge wastewater that has been agitated in the raw water tank 11 is pumped up by the pump 22, and the dust mixed in the sludge wastewater is removed by the screen means 21 and then stored in the flow rate adjusting tank 12.

(First step)
The sludge drainage stored in the flow rate adjusting tank 12 is pumped up by the pump 23 and supplied to the first aeration tank 13 via the measuring tank 24.
Further, in the first aeration tank 13 (and / or the second aeration tank 14), an enzyme that promotes the decomposition of organic sludge from the enzyme adding means 27 is contained in the sludge wastewater from the wood powder adding means 28. Each is supplied with a decay-resistant wood powder capable of carrying bacteria. As the wood powder, one containing the above-mentioned enzyme can be used, and in this case, the enzyme may or may not be supplied from the above-mentioned enzyme addition means 27.
Then, air (oxygen) is sent from the aeration means 25 and 26 to the first and second aeration tanks 13 and 14, respectively, and the inside is agitated (aeration treatment) to perform aerobic bacteria treatment.

(Second step)
The sludge wastewater that has been sequentially aerated in the first and second aeration tanks 13 and 14 is supplied to the settling tank 15.
Here, by leaving the sludge drainage in the settling tank 15 for a certain period of time without stirring, the sludge is settled at the bottom and separated into the supernatant liquid and the settled sludge.
This supernatant water is water containing almost no organic matter, and has an activated sludge suspended matter concentration of 250 mg / L or less and a BOD of 160 mg / L or less (more specifically, 10 to 50 mg / L). As it is, it can be stored in the discharge tank 17 and discharged to a river or the sea on a regular basis. Since the supernatant contains an enzyme, it has a cleaning effect and an organic matter decomposition effect by itself, and can be used as it is.
Further, the sludge settled in the settling tank 15 is extracted by the pump 31 and sent to the regeneration tank 16.

(Third step)
The sludge extracted from the settling tank 15 is put into the regeneration tank 16.
In the regeneration tank 16, by sending air from the air diffuser 33 (aeration treatment), aerobic bacteria can further act to promote the decomposition of sludge.
As described above, the sludge generated in the treatment of the reclaiming tank 16 was produced by residual enzymes, wood powder, aerobic bacteria (living and dead) and aerobic bacteria contained in the sludge wastewater. Contains enzymes and the like.

This sludge is extracted by the pump 34 and sent to the first aeration tank 13 via the circulation path 18. Here, the wood powder, the enzyme derived from aerobic bacteria, and the residual enzyme are recycled (that is, the first to third steps are repeated).
If the amount of the enzyme used for circulation to the first aeration tank 13 is insufficient, a new enzyme can be supplied to the first aeration tank 13 by the enzyme addition means 27 (wood powder is an enzyme). (In the case of containing, new wood powder may be supplied by the wood powder adding means 28), and if the supply amount of the recycled wood powder to the first aeration tank 13 is insufficient, the wood powder is added. By means 28, new wood powder can be supplied to the first aeration tank 13. Here, the shortage of the supply amount of the enzyme and / or the wood powder can be determined from, for example, the concentration of the activated sludge suspended matter in the supernatant discharged from the settling tank 15 and the measurement result of the BOD.

Although the present invention has been described above with reference to Examples, the present invention is not limited to the configuration described in the above-described Examples, but is within the scope of the claims. It also includes other possible examples and modifications. For example, the case where a part or all of the above-mentioned examples and modifications are combined to form the sludge wastewater treatment facility and the treatment method thereof of the present invention is also included in the scope of rights of the present invention.
In the above-described embodiment, the sludge wastewater treatment is performed by combining continuous treatment and batch treatment, but all of them can be performed only by continuous treatment or batch treatment.
Further, in the above-described embodiment, the case where the treated water treated in the settling tank is discharged through the discharge tank has been described, but the treated water in the settling tank can be discharged as it is without using the discharge tank.

According to the sludge wastewater treatment facility and the treatment method thereof of the present invention, sludge wastewater containing organic sludge discharged from general households, office buildings, various factories, etc. can be efficiently discharged while reducing and preventing the environmental load. Since it is treated so that the treated water can be discharged to rivers and the sea, it has industrial potential for wastewater treatment business, water environment conservation business, etc.

10: Sludge wastewater treatment equipment, 11: Raw water tank, 12: Flow control tank, 13, 14: Aeration tank, 15: Sedimentation tank, 16: Regeneration tank, 17: Discharge tank, 18: Circulation path, 19: Aeration blower , 20: Aeration means, 21: Screen means, 22, 23: Pump, 24: Measuring tank, 25, 26: Aeration means, 27: Enzyme adding means, 28: Wood powder adding means, 29: Conical part, 30 : Cylindrical part, 31: Pump, 32: Sludge measuring tank, 33: Aeration means, 34: Pump, 35: Sludge measuring tank

Claims (6)

1. An aeration tank that receives sludge wastewater containing organic sludge and aerates the sludge wastewater, and a settling tank that receives the sludge wastewater aerated by the aeration tank and separates the sludge wastewater into sediment and treated water. In a sludge wastewater treatment facility having a regeneration tank that receives the sediment accumulated in the sedimentation tank and further aerates the sediment, and a circulation path that supplies the processed product treated in the regeneration tank to the aeration tank.
   The aeration tank is characterized in that an enzyme that promotes the decomposition of the organic sludge and a wood powder having a particle size of 1 mm or less that serves as a carrier for aerobic bacteria that decompose the organic sludge are used. Wastewater treatment equipment.
2. In the sludge wastewater treatment equipment according to claim 1, the sludge wastewater treatment equipment is characterized in that the wood powder contains the enzyme.
3. In the sludge wastewater treatment facility according to claim 1 or 2, a sludge characterized in that a new enzyme for compensating for a shortage of the supply amount of the enzyme used for circulation to the aeration tank is supplied to the aeration tank. Wastewater treatment equipment.
4. In addition to putting sludge wastewater containing organic sludge into the aeration tank, wood powder having a particle size of 1 mm or less capable of carrying an enzyme that promotes the decomposition of the organic sludge and an aerobic bacterium that decomposes the organic sludge is put into the aeration tank. The first step of supplying and aerating to treat aerobic bacteria,
   The second step of putting the sludge wastewater treated in the first step into a settling tank and separating it into a sediment and treated water, and
   It has a third step of putting the precipitate generated in the second step into a regeneration tank and performing aeration treatment.
   A method for treating sludge wastewater, which comprises supplying the treated product treated in the third step to the aeration tank and circulating the wood powder.
5. The sludge wastewater treatment method according to claim 4, wherein the wood powder contains the enzyme.
6. The sludge wastewater treatment method according to claim 4 or 5, characterized in that when the supply amount of the enzyme used for circulation to the aeration tank is insufficient, a new enzyme is supplied to the aeration tank. How to treat sludge wastewater.

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