JP2003340487A - Method for supplying water to be treated of upflow anaerobic treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an upflow anaerobic treatment method by which ballooning of granules and channeling in the up flow of water to be treated are prevented and the occurrence of a possibility of outflow of the granules entrained by the treated water from a means for discharging the treated water is averted. <P>SOLUTION: The method for supplying the water to be treated of an upflow anaerobic treatment apparatus is characterized in that a means for supplying the water to be treated has discharge nozzles arranged apart prescribed intervals within an anaerobic treating vessel of the upflow anaerobic treatment apparatus and that the velocity of discharge flow of the water to be treated from the discharge nozzles is intermittently specified to 3 to 5 times that in ordinary operation. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention upwardly distributes organic wastewater through a sludge bed (hereinafter simply referred to as a sludge bed) formed by self-granulating sludge of microorganisms formed in an anaerobic treatment tank. The present invention relates to a method for supplying water to be treated in an upflow anaerobic treatment apparatus for decomposing and treating organic matter in wastewater by biological action of microorganisms.

[0002]

2. Description of the Related Art Conventionally, an upflow anaerobic treatment apparatus is one of the apparatuses for treating organic industrial wastewater and sewage such as food processing wastewater, fermentation factory wastewater, chemical factory wastewater and pulp and paper factory wastewater. This upflow anaerobic treatment device is provided with treated water supply means at the bottom, treated water discharge means and generated gas discharge means at the upper part, and anaerobic microorganisms mainly composed of methane bacteria are granulated below inside. By providing an anaerobic treatment tank in which a sludge bed is formed (hereinafter referred to as a granule), and by supplying organic wastewater from the treated water supply means to the lower part of the sludge bed to cause the sludge bed to flow upward, The granules are developed and retained at a certain height, and the anaerobic microorganisms that compose the granules biologically decompose organic matter in the wastewater to generate generated gas such as methane gas and carbon dioxide gas, treated water and granules. It is a treatment device that separates the treated water in the upper part, discharges the treated water from the treated water discharge means and the generated gas from the gas discharge means, and causes the granules to settle in the sludge bed to hold the sludge bed.

In the upflow anaerobic treatment apparatus, the anaerobic microorganisms that biologically decompose organic matter in wastewater are granulated with the microorganisms themselves or fine particles as the core, so that the microorganisms can be retained at a high density. Since it is possible to efficiently treat high-concentration organic wastewater, the installation area of the equipment can be reduced, and the methane gas produced can be used as a fuel or a raw material for the production of chemical products. Has been done.

[0004]

The means for supplying water to be treated in the conventional general upward flow anaerobic treatment apparatus has a predetermined shape in a grid or annular pipe arranged at the bottom of the anaerobic treatment tank. Distributors equipped with a large number of discharge nozzles at regular intervals are generally used, and the discharge velocity of the treated water from the discharge nozzles is continuously discharged at a constant speed of 1 to 1.5 m / sec. The formed granule diameter is maintained at about 1 to 3 mm.

However, at the above-mentioned discharge speed, suspended solids in the water to be treated and granules having a large apparent specific gravity are accumulated on the bottom portion, and a channeling phenomenon is likely to occur in the upward flow of the water to be treated, so that the locality is localized. The sludge load becomes overloaded, the biologically necessary substrate is not supplied to the entire granule, acid-producing bacteria are densely grown on the surface of the granule, and the structure of the granule becomes a structure that gas is difficult to permeate. , The specific gravity of the granules becomes large and the specific gravity becomes lighter, causing a problem of flowing out of the system.Also, if the upward flow velocity is increased, the stirring action is improved, but the granules become finer, and as described above,
Since it easily flows out of the system, it is difficult to improve the processing efficiency under high speed and high load conditions.

Therefore, the present invention has been made in view of the above-mentioned problems of the prior art, and prevents enlargement of the granules and channeling in the upward flow of the water to be treated,
It was made for the purpose of enabling highly efficient treatment of organic wastewater by providing an upflow anaerobic treatment method in which there is no risk that granules will accompany the treated water and flow out of the treated water discharge means. Is.

[0007]

Means for Solving the Problems The gist of the present invention for achieving the above-mentioned object is, in the invention described in claim 1,
A sludge bed formed by self-granulating sludge in the lower part of the anaerobic treatment tank, in which a treated water supply means is provided at the bottom and a treated water discharge means and a generated gas discharge means are provided at the top. , A gas retention part is formed at the top and a three-layer separation part for separating gas, liquid and sludge into three layers in the upper part of the sludge bed,
In an upflow anaerobic treatment apparatus that treats organic wastewater by flowing upward, the treated water supply means has discharge nozzles arranged at predetermined intervals, and the treated water discharge flow velocity from the discharge nozzle. Is intermittently set to 3 to 5 times the speed during normal operation, and the treated water supply method for an upflow anaerobic treatment apparatus is characterized.

By intermittently increasing the flow velocity of the water to be treated discharged from the discharge nozzle to 3 to 5 times that of the normal operation, the bubbles adhering to the granules are peeled and removed, and the granules are broken to seal the inside. The generated air bubbles can be separated and the particle size can be adjusted to an appropriate size that can settle and improve the contact efficiency, so the decrease of the microbial concentration due to the outflow of granules can be prevented, and the contact area between the water to be treated and the granules can be prevented. Also becomes large and high efficiency processing becomes possible.

Further, in the method according to claim 2,
The treated water discharge flow rate from the discharge nozzle during normal operation according to claim 1 is 1 to 1.5 m / sec, and the treated water discharge flow rate when the discharge flow rate is intermittently increased is 3 to 5 m / se.
It is a method for supplying untreated water of the upflow anaerobic treatment apparatus which is c.

The flow velocity of the water to be treated discharged from the discharge nozzle having the above construction is intermittently changed from 1 to 1.5 m / sec of the normal operation to 3
By the operation of about 5 m / sec, the effect of adjusting the particle size of the granules to an appropriate size that can settle and improve the contact efficiency is improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a system diagram of an upflow anaerobic treatment apparatus according to an embodiment of the present invention, FIG. 2 is a schematic plan view of a distributor that is a means for supplying treated water according to an embodiment of the present invention, and FIG. It is a particle size distribution diagram of a granule in the method for supplying untreated water of the invention and the conventional method for supplying untreated water.

In FIG. 1, reference numeral 1 denotes an anaerobic treatment tank having a closed structure and a cylindrical shape (hereinafter simply referred to as a treatment tank), but it may be a rectangular treatment tank. The treated water supply means 2 connected to the treated water supply passage 10 is provided in the lower part of the treatment tank 1, and the overflow having the solid content separating member 5 at the treated water inlet is provided in the upper part. -Means 4 are provided, to which the treated water discharge channel 12 is connected. Further, the generated gas discharge means 1 having a gas suction device (not shown) at the top
1 is provided.

In the treatment tank 1, a sludge bed A formed by self-granulating sludge below, a gas above the sludge bed A,
A three-layer separation part B that separates into three layers of liquid and sludge and a gas retention part C are formed at the top. In the three-layer separation part B, a chevron-shaped collision plate 3a in the lower stage and a gas hood 3b in the upper stage are formed. A gas collector 3 is provided which is arranged in a zigzag pattern on the upper and lower sides, forms a flow path for causing the liquid to meander and rise, and collects the generated gas and causes the floating granules 9 to be retained and settled. Also,
In the gas retention part C, a spraying means 6 is arranged which is capable of injecting a liquid toward the surface of the processing liquid and peeling and removing bubbles adhering to the floating granules 9 to settle the granules. Although the generated gas collected by the gas hood 3b is introduced into the gas retention section C, the collected generated gas may be directly extracted and stored in a gas tank or the like (not shown).

Further, the three-layer separating section B may be constituted by a gas collector having a plurality of gas hoods provided at the top and bottom, or a configuration having a plurality of gas collectors provided at the top and bottom. Further, a treated water storage tank 7 for storing a part of the discharged treated water is provided,
A treated water supply pump 8 is additionally provided and is supplied as circulating water for maintaining a predetermined upward flow velocity in the treatment tank 1 and as spray water for the spraying means 6.

As the solid content separating member 5 provided at the treated water inlet of the overflow means 4, a plate-like member formed of notches, slits, lattices, wire mesh or the like is used. However, any structure may be used as long as the microbial particles that float along with the treated water do not flow out.

Since it is preferable that the treated water supply means 2 allows the treated water to uniformly flow upward over the entire horizontal cross section of the treatment tank 1, a plurality of annular pipes arranged concentrically at the bottom of the treatment tank 1. Although the distributor in which a large number of discharge nozzles are arranged at a predetermined interval is provided in the above, the grid-like distributor may be arranged over substantially the entire bottom surface, and the present invention is not limited thereto.

As a specific embodiment of the distributor 20 which is the means for supplying water to be treated 2 shown in FIG. 2, there are two small diameters and large diameters with a predetermined distance from the treatment tank wall 25 and the bottom. The annular pipes 23a and 23b are arranged concentrically, and each of the annular pipes has a plurality of discharge nozzles 2.
4a and 24b are provided at a predetermined interval. Further, in order to supply the untreated water to the small-diameter annular pipe 23a, the untreated water supply pipe 21b having an electromagnetic valve 22b for controlling the untreated water supply amount is connected, and the large-diameter annular pipe 23b is The treated water supply pipe 21a having an electromagnetic valve 22a for controlling the amount of treated water supplied and the treated water supply pipe 21c having an electromagnetic valve 22c are connected to each other.

The operation of the present invention will be described below with reference to the drawings. Treated water of organic wastewater such as food processing wastewater is supplied from the treated water supply flow path 10 to the lower part of the treatment tank 1 through the treated water supply means 2, and the inside of the treatment tank 1 is uniformly upwardly directed. The sludge bed A of the granules 9 is formed by microorganisms such as methane bacteria that are self-granulated by using the initially filled sewage sludge as seeds by circulating it as a stream, but the granules from other devices are initially formed. 9 may be filled.

The water to be treated supplied to the treatment tank 1 is decomposed by the biological action of microorganisms in the water to be treated while flowing upward through the sludge bed A to produce methane gas, carbon dioxide gas and the like. To be done. In addition, as for the water to be treated, in normal operation, all the electromagnetic valves 22a, 22b, 22c are opened in FIG. 2, and all the annular pipes 23a, 21b, 21c are passed through the treated water supply pipes 21a, 21b, 21c. By supplying from 23b, it is supplied at a slow discharge flow velocity (for example, 1 to 1.5 m / sec) from the discharge nozzles 24a and 24b.

Further, the discharge flow velocity from the discharge nozzle is about 3 to 5 times (for example, 3 to 7.5 m / se) at a predetermined time interval.
Although the operation of c) is performed, for example, the solenoid valve 22a,
22b is closed and only the solenoid valve 22c is opened, so that the total amount of the treated water is supplied to the annular pipe 23b through the treated water supply pipe 21c, so that the discharge flow rate from the discharge nozzle 24b is about 3%. The operation of increasing the volume by 5 times is continued for about 15 seconds.

Next, the solenoid valves 22b and 2b are set at predetermined time intervals.
2c is closed and only the solenoid valve 22a is opened, so that the total amount of the treated water is supplied to the annular pipe 23b through the treated water supply pipe 21a, and the discharge flow rate from the discharge nozzle 24b is about 3 The operation of increasing the volume by 5 times is continued for about 15 seconds. Next, at a predetermined time interval, the solenoid valve 22
a and 22c are closed, and only the solenoid valve 22b is opened, so that the entire amount of water to be treated is supplied to the annular pipe 23a through the water to be treated supply pipe 21b.
About 1 to increase the discharge flow rate from a to about 3 to 5 times
Continue for 5 seconds. The solenoid valve opening / closing control is preferably performed automatically by a timer, and the series of operations is usually 1
Held once / day.

The flow velocity of the water to be treated discharged from the discharge nozzle is intermittently set to about 3 from 1 to 1.5 m / sec in the normal operation.
By 5 times to 3 to 7.5 m / sec, the bubbles adhering to the granules are peeled and removed, and the granules are sheared and broken to separate the enclosed bubbles, and the particle size is settled and contacted. They can be arranged in an appropriate size (for example, 0.5 to 1.0 mm) that can improve efficiency.

The water to be treated, in which the organic matter has been decomposed by the microorganisms in the sludge bed A, further rises and the gas collector 3 in the three-layer separation section B
And the floating granules 9 are separated by the lower mountain-shaped collision plate 3a and settled and circulated in the sludge bed A, and a part of the floating granules 9 and the produced gas meander along with the treatment liquid, Levitation granule 9 by the upper gas hood 3b
And the product gas is separated. The generated gas is the gas hood 3b
Is collected and introduced into the gas retention section C, and the floating granules 9 are settled on the sludge bed A while retaining.

The granule has an average particle size of 0.5 mm.
The sedimentation speed is 15 to 20 m / hr, and even if the liquid rising speed in the high-efficiency treatment is 10 m / hr, the sedimentation speed is higher, so that the sludge bed can be stably held. Therefore, a decrease in the concentration of microorganisms due to floating outflow of granules is prevented, and the contact area between the water to be treated and the granules becomes large, which enables highly efficient treatment.

The water to be treated from which the generated gas and the granules 9 are separated by the gas collector 3 of the three-layer separation section B further rises to the gas retention section C, and the remaining generated gas is statically separated, The residual granules 9 are separated by the solid content separating member 5 provided at the treated water inlet of the blower means 4, and are discharged from the treated water discharge passage 12 to the outside of the treatment tank as clear treated water. Further, the generated gas separated in the gas retention section C is recovered from the generated gas discharge means 11 to a gas tank or the like via a gas suction device (not shown). In addition, the water to be treated that remains in the gas retaining portion is efficiently ejected from the spraying means 6 because the bubbles adhering to the remaining floating granules 9 are removed by the treated water. Can be separated.

The clear treated water discharged from the treated water discharge channel 12 to the outside of the treatment tank 1 is discharged to the outside of the system, and a part of it is stored in the treated water storage tank 7 and then supplied to the treated water. In order to maintain a predetermined upward flow velocity in the treatment tank 1 via the pump 8 and a part of the treatment water circulation flow path 14,
The treated water is joined to the treated water supply channel 10, mixed with the treated water, circulated in the treatment tank 1, and the remaining treated water is supplied as spray water for the spraying means 6 through a spray water supply channel 13. It

[0027]

[Examples] The particle size distribution of granules in the method for supplying treated water of the present invention and the conventional method for supplying treated water was measured.
The discharge flow rate from the discharge nozzle in the conventional untreated water supply method is 1 to 1.5 m / sec, and in the untreated water supply method of the present invention, the discharge flow rate is 1 to 1.5 m / sec in normal operation. Then, the vehicle was intermittently operated at 4 m / sec once a day. As a result, in the conventional method, the granule particle size distribution is as shown in (a) the conventional untreated water supply method and (b) the untreated water supply method of the present invention, as shown in FIG. 0.6 with a peak at 1.18 to 1.00 mm
However, in the method of the present invention, the peak is 0.6 to 0.425 mm, and the peak is 0.6 to 0.425 mm.
It was arranged in a narrow range of 1.7 mm. As a result, the particle size of the granules becomes uniform and the particle size is such that an appropriate settling state can be maintained, so there is no risk of the granules being discharged along with the treated water from the treated water discharge means, and highly efficient treatment is possible. became.

[0028]

INDUSTRIAL APPLICABILITY According to the present invention, the enlargement of granules and the channeling in the upward flow of the water to be treated are prevented, and there is no fear that the granules will accompany the treated water and flow out from the treated water discharge means. , An upflow anaerobic treatment method that enables highly efficient treatment of organic wastewater.

[Brief description of drawings]

FIG. 1 is a system diagram of an upflow anaerobic treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a plan view of a distributor that is a treated water supply unit according to an embodiment of the present invention.

FIG. 3 is a particle size distribution chart of granules in the method for supplying treated water according to one embodiment of the present invention and the conventional method for supplying treated water.

[Explanation of symbols]

1: Anaerobic treatment tank 2: Treated water supply means 3: Gas collector 4: Overflow means 5: Solid content separating member 6: Spraying means 7: Treated water storage tank 8: Treated water supply pump 9: Granule 20: Distributor 21a, 21b, 21c: Treated water supply pipe 22a, 22b, 22c: Solenoid valve 23a, 23b: Ring pipe 24a, 24b: discharge nozzle

Claims (2)

[Claims] 1. An anaerobic treatment tank having a treated water supply means at the bottom and a treated water discharge means and a generated gas discharge means at the top, wherein self-granulated sludge is provided below the anaerobic treatment tank. The formed sludge bed, a three-layer separation section for separating gas, liquid and sludge into three layers in the upper part of the sludge bed and a gas retention section at the top are formed, and the organic wastewater is circulated upward for treatment. In the upflow anaerobic treatment apparatus, the treated water supply means has discharge nozzles arranged at a predetermined interval, and the treated water discharge flow velocity from the discharge nozzle is intermittently 3 to 5 during normal operation.
A method for supplying water to be treated in an upward-flow anaerobic treatment device, which is characterized by a double speed. 2. The treated water discharge flow velocity from the discharge nozzle during normal operation is 1 to 1.5 m / sec, and the treated water discharge flow velocity when the discharge flow velocity is intermittently increased is 3 to 5 m / sec. The method for supplying water to be treated in the upflow anaerobic treatment apparatus according to claim 1, wherein