JPH1157769A - Anaerobic treatment equipment for organic waste water - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable withdrawal of treated water which is not contaminated with sludge even when the COD (Cr) load of organic waste water to be treated (raw water) is high and a large amount of anaerobic gas is generated and also to enable biological treatment of organic matter in the raw water, that involves returning sludge subjected to sedimentation treatment to a reaction section without crushing the sludge by utilizing the generated anaerobic gas, with the equipment. SOLUTION: This equipment is provided with a baffle plate 21 for preventing anaerobic gas from entering into an ascending water passage 19, below the lower end of the ascending water passage 19. In this equipment, the baffle plate 21 is fitted to a conical bottom 15 of a sedimentation section 14 so that the baffle plate 21, together with the conical bottom 15, forms a double-chevron-shaped cross-section and also, a sludge return pipe 23 the lower end of which is open inside the sedimentation section 14 in the vicinity of the conical bottom 15 and the upper part of which projects upward from the water surface and is opened outside a cylindrical partition wall 18, is placed. Thus, anaerobic gas that is generated in a reaction section 11 and then trapped and collected by the baffle plate 21, or blown gas from the outside is supplied into the sludge return pipe 23 and accordingly, sludge sedimented on the conical bottom 15 of the sedimentation section 14 is returned to the reaction section 11 through the sludge return pipe 23 by the gas lift action effected within the sludge return pipe 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for converting organic matter in organic wastewater into granules composed of anaerobic microorganisms constituting sedimentation and self-granulated sludge (a granule having a small particle size) as a precursor thereof. Finally, it is decomposed into anaerobic gas mainly composed of methane and carbon dioxide to remove organic matter, and the treated water after the decomposition of organic matter is separated from the generated anaerobic gas and sludge. The present invention relates to a UASB type (upflow sludge blanket type) anaerobic treatment apparatus which is separated and taken out.

[0002]

2. Description of the Related Art The present applicant has filed a Japanese Patent Application No. Hei 8-24992.
According to No. 0 and No. 352362, the above-mentioned reaction part inside a treatment tank having a reaction part 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 tank, a bottomed cylindrical sediment with a cone-shaped bottom and an upper end protruding above the water surface in the tank is arranged, and at the upper part in the sediment, treated water is taken out of the treatment tank. A spillover device is provided, and a cylindrical partition wall whose upper end protrudes above the water surface in the tank is arranged around the sedimentation section at intervals along the sedimentation section, and between the sedimentation section and the cylindrical partition wall. A rising channel into which a part of the treated water rising from the reaction section flows, and a communication means for communicating the rising channel with the inside of the sedimentation section, and below the lower end of the rising channel, in the rising channel. An anaerobic treatment device for organic wastewater with a baffle to prevent anaerobic gas from entering was proposed. In this prior proposal device, the sedimentation section has a lower end closed, and the interior of the sedimentation section is not affected at all by the treated water that rises in the rising water channel between the cylindrical partition wall and the water flow of the anaerobic gas that floats, Granules and their 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, preventing sludge from flowing into the treated water. it can. Therefore, organic wastewater C
Even if the ODcr load is high and the amount of anaerobic gas generated is large,
Regardless of that, it has become possible to collect supernatant treated water that does not mix with sludge.

[0003]

In the above-mentioned prior proposed apparatus, the bottom of the sedimentation section and the reaction section are connected by a sludge return pipe partially out of the treatment tank, and the sludge return pipe is connected to the treatment tank. A pump is connected to the part outside of the reactor, and the pump is operated continuously or intermittently to return sludge settled at the bottom of the settling section to the reaction section. In this case, especially for a large-sized device, the number of devices is increased, and the running cost of pump operation is also required.

[0004]

According to the present invention, a baffle for preventing anaerobic gas from entering the rising channel is provided on the cone-shaped bottom of the settling section in order to solve the above-mentioned problems of the prior proposed apparatus. Mounted in a C-shaped cross section, the lower end is opened near the bottom of the cone inside the sedimentation section, the upper part is provided with a sludge return pipe protruding above the water surface and opened outside the cylindrical partition wall, and the reaction section The anaerobic gas generated and collected by the baffle plate, or the blown gas from the outside is supplied to the sludge return pipe, and the sludge settled at the bottom of the settling section by the gas lift action generated in the sludge return pipe is supplied to the reaction section. It is characterized by being returned.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the illustrated embodiment, reference numeral 10 denotes a covered processing tank having a degassing pipe 10 'at the top, 12 denotes an anaerobic sludge layer made of sludge formed inside the processing tank, and 13 denotes the anaerobic sludge. This is a water supply pipe that supplies raw water (organic wastewater) into the bed and makes it flow upward. The sludge that forms the anaerobic sludge layer flows into the middle of the height of the treatment tank due to the raw water that flows upward. I do. The reaction section 11 is formed in the lower half of the treatment tank by the raw water supply pipe 13 and the anaerobic sludge layer 12 which is developed in a fluidized state.

[0006] Above the reaction section 11 inside the processing tank,
The sedimentation part 14 which consists of a bottomed cylindrical wall whose upper end protrudes above the water surface W in the tank is arranged. The bottom 15 of the sedimentation part 14 is closed in a cone shape with a V-shaped cross section, and is located at a distance above the reaction part 11. An overflow device 16 into which the treated water in the settling section overflows is provided in the upper part of the settling section, and the treated water overflowed into the overflow device is taken out of the tank by a drain pipe 17. The overflow device 16 is a trough provided along the upper inner periphery of the settling unit 14.

Reference numeral 18 denotes a cylindrical partition wall surrounding the sedimentation section 14 with a space therebetween, the upper end of which protrudes above the water surface W in the tank similarly to the sedimentation section, and the lower end part 18 'is formed of the sedimentation section. It is conically narrowed like the upper part of the cone-shaped bottom. Settling part 1
An ascending channel 19 into which a portion of the treated water ascending from the reaction section 11 flows is formed at an annular interval between the portion 4 and a partition wall surrounding the portion 4. The communication means 2 for supplying a part of the treated water rising in the rising water channel 19 to the inside of the sedimentation section 14.
0 is provided. In the illustrated embodiment, the communicating means 20 is formed at a vertical annular interval provided between the upper part 14a of the sedimentation part 14 and the cone-shaped bottom 15. The lower end 14 'of the upper portion 14a of the sedimentation section is conically narrowed, and the diameter of the lower end of the lower end 14' is smaller than the diameter of the upper end of the cone-shaped bottom 15. Therefore, the communicating means 20 is formed obliquely by the upper part of the cone-shaped bottom 15 and the conical lower end part 14 'at the upper part of the sedimentation part.

A baffle plate for preventing the anaerobic gas floating from the reaction part 11 from flowing into the rising water passage 19 formed between the outer surface of the sedimentation part and the inner surface of the partition wall surrounding the sedimentation part. 21 is arranged. The bottom 15 of the sedimentation section is cone-shaped,
The lower end 18 ′ of the partition wall 18 is the conical bottom 14 of the sedimentation section.
In the case of the illustrated embodiment which ends shortly from the top of FIG. 2B, the baffle plate 21 having a C-shaped cross section substantially perpendicular to the cone-shaped bottom of the sedimentation section is slightly separated from the lower end of the partition wall 18 by the sedimentation. Secure to the outside of the bottom of the part.

As a result, the raw water (organic wastewater) that is supplied from the water supply pipe 13 into the treatment tank and flows upward in the reaction section 11 and develops the anaerobic sludge layer 12 in a fluidized state is developed in a fluidized state. Organic matter contained in contact with sludge is decomposed by anaerobic microorganisms to become treated water. The treated water accompanies the anaerobic gas generated and decomposed by the decomposition, and further flows upward from the reaction section 11 with some sludge.

A part of the upwardly flowing treated water flows from below into the rising water passage 19 and rises in the water passage, and the rest of the treated water rises outside the partition wall 18 and is contained in the treated water. The air bubbles of the anaerobic gas floating on the surface of the treatment tank and degassing pipe 1
It is released from 0 '. Even if the anaerobic gas is contained in some of the treated water flowing into the ascending channel 19 and rising, the anaerobic gas floats on the liquid surface of the ascending channel and the gas vent pipe 10 '.
The baffle 21 is provided below the lower end of the rising channel, so that the treated water flowing into the rising channel mainly rises toward the baffle, The anaerobic gas contained in the treated water is detoured around the edge, so that the anaerobic gas contained in the treated water has an annular space 2 having a mountain-shaped cross section formed by the baffle plate 21 and the cone-shaped bottom 15 of the sedimentation section.
2 can be prevented from entering the ascending water channel 19, and the sludge rolled up with the gas can be largely prevented from flowing into the sedimentation section.

Part of the treated water flowing into the rising water channel 19 is
It flows into the sedimentation part 14 from the communication means 20 provided in the middle of the rising water channel 19. As described above, the upper part 14a of the sedimentation section
Of the condensed bottom 15 is smaller than the diameter of the upper end of the cone-shaped bottom 15, so that the sludge contained in the treated water flowing into the rising water passage 19 is obliquely downwardly communicating means. 20, the sediment is easily settled on the sedimentation part 14 along the upper part of the cone-shaped bottom 15.

Since the upper end of the sedimentation section projects above the water surface in the treatment tank and the bottom is closed, the interior of the sedimentation section is treated water flowing upward outside the partition wall 18 or anaerobic floating. The sludge contained in the treated water flowing into the sedimentation section is free to settle on the cone-shaped bottom of the sedimentation section according to its own sedimentation, because it is not affected by the water flow due to the volatile gas. The supernatant treated water separated from the water flows into the overflow device 16 and flows out of the tank through the drain pipe 17. The rising flow rate of the treated water in the sedimentation section was determined by the aforementioned UA using granules.
In the case of the SB system, 3 to 30 m / hour is appropriate.

As the operation time elapses, the amount of sludge settled on the cone-shaped bottom of the settling section gradually increases, and the amount of anaerobic sludge in the reaction section 11 decreases accordingly. In order to prevent this, the lower end is opened near the cone-shaped bottom inside the sedimentation section, the upper part is protruded above the water surface and bends sideways, and the sludge return pipe 23 opened on the water surface outside the partition wall 18 and In the illustrated embodiment, one or a plurality of degassing pipes 24 are provided, the lower end of which communicates with the annular space 22 having a chevron cross section in which the anaerobic gas accumulates, and the upper end of which is connected in the middle of the sludge return pipe 23.

As a result, the anaerobic gas to be accumulated in the annular space 22 having a mountain-shaped cross section formed by the baffle plate 21 and the cone-shaped bottom 15 is exhausted to the sludge return pipe 23 by the degassing pipe 24, and the anaerobic gas is discharged. A gas lift action occurs due to the flow of the anaerobic gas, and the sludge that settles and accumulates on the cone-shaped bottom is sucked into the sludge return pipe, and the cylindrical partition wall 1
8 falls on the water surface in the tank and is returned.

The gas lift effect generated in the sludge return pipe is as follows:
Since the amount of anaerobic gas floating in the annular space 22 is proportional to the amount of anaerobic gas generated, the amount of sludge returned increases when the amount of generated anaerobic gas is large, and the amount of returned sludge decreases when the amount of generated anaerobic gas is small. However, since the amount of sludge flowing into the sedimentation section, that is, the amount of sludge required to return, is proportional to the amount of anaerobic gas generated, sludge is deposited according to the amount of sludge deposited on the cone-shaped bottom of the settling section. Can be returned.

When the amount of anaerobic gas generated is extremely small, the release of the anaerobic gas from the gas vent tube 10 'is restricted or stopped, and the anaerobic gas stored in the space above the processing tank is blown out. For example, the sludge may be supplied to the annular space 22 or supplied to the sludge return pipe 23 to cause a gas lift action in the sludge return pipe to increase the sludge return amount.

[0017]

As is evident from the above, according to the present invention, even if the organic wastewater has a high CODcr load and a large amount of anaerobic gas is generated, regardless of the amount of the anaerobic gas, the sludge is not mixed. In addition to having the same effect as the previous proposal, which can collect treated water, equipment costs for returning sludge, such as pumps, valves, and timers, are unnecessary, so equipment costs are low, and running costs for pump operation are also unnecessary. Become. This is a particularly great advantage when a plurality of anaerobic treatment devices are installed. Further, when the sludge is returned using the pump, the sludge is crushed inside the pump. However, in the present invention, the sludge is returned by the gas lift action, so that the sludge is not damaged. Therefore, there is also an effect that the growth of the granule particles is stabilized.

[Brief description of the drawings]

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

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Treatment tank 11 Reaction part 12 Anaerobic sludge layer of reaction part 13 Water supply pipe to reaction part 14 Sedimentation part 15 Cone-shaped bottom of sedimentation part 16 Overflow device of sedimentation part 17 Drainage pipe from overflow device 18 cylindrical Partition wall 19 Ascending channel 20 Communication means 21 Baffle plate 22 Space where anaerobic gas accumulates 23 Sludge return pipe 24 Gas release pipe

Claims (1)

[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 cylindrical bottom with a cone-shaped bottom, the upper end of which protrudes above the surface of the water inside the tank, and an overflow for removing treated water out of the processing tank A device is provided, and a cylindrical partition wall whose upper end protrudes above the water surface in the tank is disposed around the sedimentation section at intervals along the sedimentation section, and a reaction section is provided between the sedimentation section and the cylindrical partition wall. Forming a rising channel into which a portion of the treated water rising from the inlet flows, and providing a communication means for communicating the rising channel with the inside of the sedimentation section; below the lower end of the rising channel, an anaerobic gas is introduced into the rising channel. In an anaerobic treatment device for organic wastewater provided with baffles to prevent the intrusion of At the bottom, a C-shaped cross-section is attached, the lower end is opened near the cone-shaped bottom inside the sedimentation section, and the upper part is provided with a sludge return pipe that protrudes above the water surface and opens outside the cylindrical partition wall. The anaerobic gas generated in the section and collected by the baffle plate or the blowing gas from the outside is supplied to the above-mentioned sludge return pipe, and the sludge settled to the bottom of the settling section by the gas lift action generated in the sludge return pipe is reacted. An anaerobic treatment device for organic wastewater, wherein the device is returned to a department.