JPH1094794A - Organic waste water anaerobic treatment device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To gather treated water in which sludge is not mixed and also to forcibly return sludge which has been subjected to sedimentation to a reaction part to completely subject organic matter to biological treatment irrespective of the case in which the quantity of a CODcr load of organic waste water (raw water) to be treated is high and the generated quantity of anaerobic gas is large. SOLUTION: A treating tank 20 is provided with a reaction part 21 having an anaerobic sludge bed 22 and a water supply pipe 23 for feeding organic waste water in a upflow into the sludge bed 22, in the bottom part thereof. Inside the treating tank 20 and above the reaction part 21, a sedimentation part 24 having the bottom whose upper end part is projected above the surface of the water in the tank 20 is arranged. And outside the sedimentation part 24, a partition 28 whose upper end is projected above the surface of the water in the tank is arranged leaving a space along the sedimentation part 24. The space is made a rising waterway 29 into which a part of treated water rising from the reaction part 21 flows. The rising waterway 29 and the inside of the sedimentation part 24 are made to communicate with each other, and also below the lower end of the rising waterway 29, a baffle plate 32 for preventing anaerobic gas from entering the rising waterway 29 is provided. And between the bottom part 24' of the sedimentation part 24 and the reaction part 21, a returning pipe 31 for returning the sludge settled on the bottom of the sedimentation part 24 to the reaction part 31 is provided, and treated water is taken out to outside the tank from the upper part in the sedimentation part 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for converting organic matter in an organic wastewater into an anaerobic mixture mainly composed of methane and carbon dioxide by means of self-granulated sludge (granules) composed of anaerobic microorganisms constituting sediment. Decomposes into volatile gases to remove organic matter,
The anaerobic gas generated,
And a UASB type (upflow sludge blanket type) anaerobic treatment apparatus which is separated and taken out from granules.

[0002]

2. Description of the Related Art As shown in FIG.
1, an inclined separating plate 12 whose upper end protrudes above the water surface in the tank, is inclined below the water surface, and whose lower end is located at the middle of the height of the tank. Sludge sedimentation chamber 13 and reaction chamber 14 provided separately in the tank by
And an anaerobic sludge layer 15 formed on the bottom of the tank in the reaction chamber.
And a water supply pipe 1 for supplying organic wastewater into the anaerobic sludge layer.
6, an overflow trough 17 for treated water provided in contact with an inclined separation plate in the upper part of the sludge settling chamber, and a gas separation inclined in the lower part of the sludge settling chamber inside the reaction chamber. An anaerobic treatment device for organic wastewater comprising a plate 18 is conventionally known. The planar shape of the treatment tank 10 may be a cylindrical shape or a rectangular tube shape. In the case of the cylindrical shape, the inclined separating plate 12 is a conical tube having a diameter decreasing downward, and the gas separating plate 18 is a jinkasa shape. In addition, the conical plate of the inclined separation plate has an upper half 12a.
And the upper part is composed of a lower half part 12b whose diameter is slightly larger than the lower part of the upper half part. The lower part of the upper half and the upper part of the lower half are fitted concentrically inside and outside, and a gas-like gas between them A conical passage 12 'is formed toward the peripheral surface of the separator. With such a configuration, the lower opening of the sludge settling chamber 13 is covered with the gas separation plate 18 from below, leaving the flow path.

[0003] Raw water (organic wastewater) supplied to the treatment tank from the water supply pipe 16 is decomposed by the granules constituting the sludge layer to treat the organic matter contained therein when the raw water (organic wastewater) rises in the anaerobic sludge layer. The treated water flows upward in the reaction chamber 14 with some granules accompanying the rise of the anaerobic gas generated by the decomposition. Then, a part of the treated water enters the sludge settling chamber 13 from the periphery of the gas separation plate 18 through an inlet at the lower end, and becomes an upward flow A rising in the chamber. The inlet at the lower end of the sludge sedimentation chamber is blocked by the gas separation plate 18, and the treated water with the granules does not directly flow upward into the sludge separation chamber, so that the gas is separated and the treated water flowing into the sludge sedimentation chamber is separated. The granules contained in the upward flow A are separated in the room, and the granules fall on the gas separation plate from the inlet at the lower end of the sedimentation room against the treated water flowing into the sludge sedimentation room, and around the gas separation plate. And settles on the anaerobic sludge layer 15. Therefore, the treated water separated from the granules overflows into the overflow trough 17,
It is taken out from the discharge pipe 19. In addition, a part of the generated anaerobic gas collects under the gas separation plate 18, and from around the gas separation plate or from both ends of the gas separation plate having a chevron-shaped cross section when the processing tank has a rectangular tube shape, outside the sedimentation chamber. It floats on the liquid surface and is discharged from the gas vent tube 11.

[0004] The remaining treated water containing the granules that have not flowed into the sludge sedimentation chamber rises to the upper part of the reaction chamber around the inclined separation plate 12 with the anaerobic gas, and the anaerobic gas is removed from the reaction chamber. It floats on the liquid surface and is discharged from the gas vent tube 11.
The rising speed of the treated water that rises with the anaerobic gas is determined by the CODcr load in the raw water, that is, the amount of anaerobic gas generated. The higher the CODcr load, the larger the amount of anaerobic gas generated. And the rate of rise of the treated water is increased.
Thus, the treated water that released the anaerobic gas in the reaction chamber
As a reverse flow C of the upward flow B due to the anaerobic gas, the flow descends along the outside of the inclined separation plate 12 in the conical passage 12 'below the inclined separation plate in the reaction chamber, and the granules contained in the treated water are anaerobic. It settles on the activated sludge layer 15.

[0005]

SUMMARY OF THE INVENTION The above-mentioned conventional apparatus is a COD.
If the organic wastewater has a cr load of up to about 15 kg / COD / m ³ / day, it can be sufficiently treated.
In the case of an organic wastewater having an OD load of 20 kg / COD / m ³ / day or higher, the amount of generated anaerobic gas is large, so that the ascending flow B in the reaction chamber and the subsequent outside of the inclined separation plate The reverse flow C descending along the passage 12 ′ along the path becomes high speed, violently impinges on the gas separating plate 18, and partly becomes a reflective upward impinging flow D and enters the inside of the sedimentation chamber 13, The granules to be settled in the settling chamber are prevented or the settled granules flow into the overflow trough 17 and the discharge pipe 1
Granules may be mixed in the treated water taken out from the tub 9. That is, since the reverse flow C descending along the inclined separation plate 12 in the reaction chamber utilizes the reverse flow of the upward flow B rising in the reaction chamber due to the anaerobic gas, COD
The rise in the flow velocity of the updraft B with the rise in the cr load is the reverse flow C
As a result, the vertically upward impinging flow D, which rises reflexively into the sedimentation chamber 13 and agitates the inside of the chamber, has a non-negligible adverse effect. Obstruction or granulation flows out to the discharge pipe 19. Also, the granules separated in the sludge sedimentation chamber must flow into the chamber and fall on the gas separation plate against the flow of the treated water that becomes the upflow A, so that the granules stay in the sludge sedimentation chamber. However, the amount of sludge in the anaerobic sludge layer 15 may be insufficient.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method for assuring the presence of granules contained in treated water without being affected by the upward flow of treated water due to anaerobic gas even when the CODcr load of raw water is high. The above-mentioned problems of the conventional device are completely eliminated by forcibly returning the separated granules to the anaerobic sludge layer, and the anaerobic treatment device for the organic wastewater has an anaerobic Inside a treatment tank provided with a reaction section having an activated sludge layer and a water supply pipe for supplying organic wastewater into the sludge layer in an upward flow, above the reaction section, the upper end has a water surface in the tank. A settling part with a bottom protruding upward is arranged, and an overflow trough for taking out treated water out of the treatment tank is provided at an upper part in the settling part. Outside the sedimentation part, an upper end part has a water surface in the tank. Place the partition walls that protrude upward along the sedimentation section with The above-mentioned space between the partition wall and the partition wall is a rising channel into which a part of the treated water rising from the reaction section flows, and communicates with the inside of the rising channel and the sedimentation section. A baffle plate is provided to prevent anaerobic gas from entering the ascending channel, and a return pipe is provided between the bottom of the sedimentation section and the reaction section to return sludge settled on the bottom of the sedimentation section to the reaction section. It is characterized by having.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Inside the settling section, an upper end protrudes above the water surface in the tank, and a lower end has a feed well located in the settling section, and a feed well is provided between the rising channel and the feed well. A communication channel is provided to supply treated water overflowing from the surface of the rising channel to the sedimentation section via the feed well.
It is preferable to provide a baffle below the lower end of the feed well in the settling section.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In each of the embodiments shown in FIGS. 1 and 2, reference numeral 20 denotes a covered processing tank having a gas vent pipe 20 'at the top, reference numeral 22 denotes an anaerobic sludge layer made of granules formed inside the processing tank, and reference numeral 23 denotes a processing tank. Is a water supply pipe for supplying raw water (organic wastewater) into the above-described anaerobic sludge layer and flowing the water upward, and the granules constituting the anaerobic sludge layer are formed in the height of the treatment tank by the raw water flowing upward. To a fluid state. Raw water supply pipe 23
And the anaerobic sludge layer 22 that develops into a fluidized state constitutes a reaction section 20 in the lower half of the treatment tank.

Above the reaction section 21 inside the processing tank,
A sedimentation part 24 with a bottom whose upper end protrudes above the water surface W in the tank is arranged. The bottoms 24 ′ of the sedimentation sections 24 are each closed in a V-shaped cross section in the illustrated embodiment, and are located at a distance above the reaction section 21. An overflow trough 25 into which the treated water in the settling section overflows is provided in the upper part of the settling section, and the treated water overflowing the overflow trough is taken out of the tank by a drain pipe 26.

Inside the sedimentation section 24, there is provided a feed well 27 having an upper end protruding above the water surface in the tank.
The lower end of the feed well is located at the middle of the height of the settling section. The feedwell may be cylindrical or rectangular. Providing the feed well 27 in this manner is preferable because the water flow in the upper part in the settling part is not disturbed.

Outside the sedimentation section 24, a partition wall 28 whose upper end protrudes above the water surface in the tank is arranged at intervals along the sedimentation section, and at the above-mentioned interval between the sedimentation section and the partition wall, Reaction unit 21
The rising water channel 29 into which the treated water rising from the inflow flows. Then, between the rising water channel 29 and the feed well 27, treated water overflowing from the surface of the rising water channel is introduced below the water surface inside the feed well, and supplied from the lower end of the feed well to the inside of the sedimentation section. A communication channel 30 is provided.

Although a preferred embodiment is shown in FIGS. 1 to 3, the feed well and the connecting water channel may be omitted, and the water in the rising water channel may be directly introduced into the settling section. For example, a communication opening communicating the rising channel and the inside of the sedimentation section may be provided on a wall constituting the sedimentation section, and water may be supplied directly from the rising channel to the sedimentation section.

A return pipe 3 for returning sludge settled at the bottom of the settling section to the reaction section is provided between the bottom of the settling section 24 and the reaction section 21.
1 is provided. A pump P is connected to the return pipe 31, and the pump is operated continuously or intermittently to supply sludge from the bottom of the settling section to the reaction section.

Below the lower end of the rising water channel 29 formed at the interval between the outer surface of the settling section and the inner surface of the partition wall, the reaction section 2 is provided.
A baffle plate 32 for preventing the anaerobic gas floating from 1 from flowing into the rising water channel is arranged. In the case of the embodiment of FIG. 1 in which the bottom 24 'of the sedimentation section is closed in a V shape as shown and the lower end of the partition wall 28 ends shortly from the top with the V shape of the lower half of the sedimentation section, the partition wall 28 is used. The baffle is fixed to the lower half of the sedimentation section at a slight angle from the lower end of the sedimentation section, at a right angle to the V-shaped lower half of the sedimentation section. FIG. 2 shows that the lower end of the partition wall 28 extends long along the vicinity of the V-shaped closed bottom of the sedimentation section.
In the case of this embodiment, a baffle plate having a chevron cross section is arranged slightly below the two lower ends of the partition wall 28.

A baffle 3 having a chevron cross section is located slightly below the lower end of the feed well 27 inside the settling section 24.
3 may be arranged.

The plan shapes of the treatment tank 20 and the sedimentation section 24 may be circular or square. Further, the planar shape of the treatment tank may be square and the planar shape of the sedimentation section may be circular. Conversely, the planar shape of the treatment tank may be circular and the planar shape of the sedimentation section may be rectangular. FIG. 3A shows a case where both the treatment tank and the sedimentation section are circular and are arranged concentrically. In this case, the upper half of the sedimentation section is cylindrical, and the lower half and the bottom 24 'are conical with the tip pointed downward, and the partition wall 28 is also formed along the upper half of the sedimentation part. Is cylindrical, and the lower half and the portion along the bottom 24 'are conical with the diameter decreasing downward, and the baffle plate 32 of FIG.
Is a conical shape whose diameter is enlarged downward, and the baffle plate in FIG. The overflow trough 25 is provided along the upper inner periphery of the cylindrical settling portion, and the feed well 2
Reference numeral 7 denotes a cylindrical shape, which stands upright at the center of the sedimentation section, and has a baffle-shaped baffle 33 arranged concentrically below the feed well.
The sedimentation section, the partition wall, and the baffle-shaped baffle plate in FIG. 2 are supported on the treatment tank by a radial support (not shown).

On the other hand, FIG. 3B shows a case where the planar shape of the processing tank is square. In this case, a cone-shaped sedimentation section 24 slightly inwardly spaced from the two opposed side walls 20a and 20b of the processing tank and having a V-shaped lower end closed, and two partition walls 28 along both outer sides of the sedimentation section. , 28 are fixed. The sedimentation section and the side walls 20a of the two partition walls 28, 28;
The end facing 20b is closed with an end wall. The feed well 27 erected at the center of the sedimentation section is connected to both side walls 20a and 2a.
0b, the number is not limited to one, and two as shown in FIG.
A plurality can be provided. Further, the overflow troughs 25 may be individually provided on the inner upper portions of the two upper halves of the sedimentation section, or both overflow troughs may be provided along the end walls closing both ends of the sedimentation section. The troughs 25 ', 25' may be connected as shown to form a corridor. The baffle 32 of FIG.
Separated downward from the lower ends of the partition walls 28, 28, and fixed to the lower left and right halves of the sedimentation section in a C shape. Also, the baffle plate 32 of FIG.
, Place the chevron plate slightly below the bottom of the sedimentation section. And the baffle 33 arrange | positioned below a feed well is fixed, and both ends of a chevron cross-section board are fixed to the end wall which closes both ends of a sedimentation part. The settling part, both end walls of the partition wall and the baffle 33 of the chevron section plate in FIG. 2 are supported by the support on both side walls 20a and 20b of the processing tank, not shown.
An interval is maintained between the side walls 20a and 20b.

Raw water (organic wastewater) supplied from the water supply pipe 23 into the treatment tank and flowing upward in the reaction section 21 to develop the anaerobic sludge layer 22 in a fluidized state is converted into sludge (granulated) in a fluidized state. ) And the contained organic matter is decomposed into treated water. Then, the treated water accompanies the anaerobic gas generated and floated by the decomposition, and further flows upward from the reaction section 21 with some granules.

A part of the treated water flowing upward flows into the rising water passage 29 from below and rises in the water passage, and the remaining part of the treated water rises outside the treatment tank partition wall 28, and flows into the treated water. Bubbles of the contained anaerobic gas float on the water surface of the treatment tank and are discharged to the outside through the vent pipe 20 '. Even if the anaerobic gas is contained in some of the treated water flowing into the ascending channel 29 and rising, the anaerobic gas floats on the liquid surface of the ascending channel and is discharged from the degassing pipe 20 ′. However, if the baffle plate 32 is provided below and below the lower end of the rising channel, the treated water flowing into the rising channel rises mainly toward the baffle plate and bypasses the edge of the baffle plate. Therefore, the anaerobic gas contained in the treated water accumulates under the baffle plate and can be prevented from entering the ascending channel 29, and the granules rolled up with the gas are prevented from flowing into the sedimentation section. Most can be prevented.

The treated water flowing into the rising water channel 29 overflows into the upper end of the connecting water channel 30 opened above the water surface, flows through the water channel, flows into the feed well 27, and flows from the lower end of the feed well to the sedimentation section. It is supplied in the middle of a height of 24. Since the upper end of the settling portion projects above the water surface in the treatment tank and the bottom is closed, the sedimentation portion may be affected by the treated water flowing upward outside the partition wall 28 or the water flow by the anaerobic gas floating. Therefore, granules contained in the treated water supplied to the sedimentation section and its precursors (small particle size granules) settle freely at the bottom of the sedimentation section according to its own sedimentation property, The supernatant treated water separated from the water flows into the overflow trough 25 and flows out of the tank from the drain pipe 26. The rising flow rate of the treated water in the settling section is preferably about 3 to 30 m / hour.

A baffle 33 is provided below the feed well 27.
If provided, the treated water supplied downward from the lower end of the feed well into the sedimentation section is turned obliquely downward by the baffle, so as to sow or settle the granules deposited on the lower end of the sedimentation section This is preferable because it does not disturb the granules.

The granules deposited on the bottom of the sedimentation section 24 are continuously or intermittently returned to the reaction section 21 by the operation of the pump P via the return pipe 31. The amount of the granules returned to the reaction section by the return pipe 31 is preferably about 1 to 5% of the amount of the supernatant treated water taken out by the drain pipe 26.

[0023]

As is clear from the above, according to the present invention, the lower end of the sedimentation section is closed, and the interior of the sedimentation section is completely affected by the treated water rising outside the partition wall and the flow of the anaerobic gas flowing up. Because it does not receive, the granules and its precursors contained in the treated water are allowed to settle by their own sedimentation, and the treated water can be taken out of the tank from the overflow trough in the sedimentation section, and the sludge flows out into the treated water Can be prevented. Therefore, even if the CODcr load of the organic wastewater is high and the amount of generated anaerobic gas is large, it is possible to collect the supernatant treated water which is not mixed with the sludge regardless of the amount. The sludge settled on the sedimentation section is forcibly returned to the reaction section by a return pipe, so that the amount of anaerobic sludge in the reaction section can be prevented and the organic matter in the raw water can be completely biologically treated. it can.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a first embodiment of an anaerobic treatment device of the present invention.

FIG. 2 is a schematic longitudinal sectional view of a second embodiment of the anaerobic treatment device of the present invention.

FIG. 3A is a cross-sectional plan view of an example taken along line AB in FIGS. 1 and 2, and FIG. 3B is a schematic longitudinal sectional view of another example of the anaerobic treatment device of the present invention. .

FIG. 4 is a schematic longitudinal sectional view of a conventional anaerobic treatment device.

[Explanation of symbols]

 Reference Signs List 20 treatment tank 21 reaction part 22 anaerobic sludge layer of reaction part 23 water supply pipe of reaction part 24 sedimentation part 24 ′ bottom of sedimentation part 25 overflow trough of reaction part 26 drainage pipe from overflow trough 27 feed well 28 partition wall 29 Ascending channel 30 Connecting channel 31 Return pipe 32 Baffle plate 33 Baffle

Claims (2)

[Claims] 1. Inside a treatment tank having a reaction section having an anaerobic sludge layer at the bottom and a water supply pipe for supplying organic wastewater in an upward flow in the sludge layer, above the reaction section. , A bottomed sedimentation part whose upper end protrudes above the water surface in the tank is provided, and an overflow trough for taking out the treated water out of the treatment tank is provided above the sedimentation part. , A partition wall whose upper end protrudes above the water surface in the tank is arranged at intervals along the sedimentation section,
The above-mentioned interval between the sedimentation part and the partition wall is a rising waterway into which a part of the treated water rising from the reaction part flows, and communicates with the inside of the rising waterway and the sedimentation part, and below the lower end of the rising waterway A baffle for preventing anaerobic gas from entering the rising channel, and a return pipe between the bottom of the settling section and the reaction section for returning sludge settled on the bottom of the settling section to the reaction section. An anaerobic treatment device for organic wastewater, characterized by comprising: 2. The anaerobic treatment apparatus for organic waste water according to claim 1, wherein a feed well having an upper end projecting above the water surface in the tank and a lower end located in the sediment is provided inside the sediment. An erecting channel is provided between the rising channel and the feed well, and a communication channel for supplying treated water overflowing from the surface of the rising channel to the settling portion through the feed well is provided between the rising channel and the feed well. An anaerobic treatment device for organic wastewater, comprising a baffle provided below.