JP2003326294A - Anaerobic water treatment apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anaerobic water treatment apparatus which does not make the time for treatment longer and does not entail upsizing of the apparatus even when a BOD of raw water is high in concentration. <P>SOLUTION: A treating vessel 12 is internally provided with supply ports 13a, 13b and 13c for supplying the raw water containing organic matter into the treating vessel 12 at three points in the depth direction of the treating vessel 12. The first supply port 13a is disposed at the bottom of the treating vessel 12 and the second supply port 13b is disposed 2 m above the first supply port 13a. Further, the third supply port 13c is disposed 2 m above the second supply port 13b. The first to third supply ports 13a to 13c are formed to an annular shape and are so disposed as to be respectively paralleled. The apparatus is so arranged that the raw water is spouted respectively from the first to third supply ports 13a to 13c toward the upper part of the treating vessel 12. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an anaerobic water treatment device for treating raw water using anaerobic microorganisms.

[0002]

2. Description of the Related Art FIG. 3 is a schematic view of a conventional apparatus body 1. As shown in FIG. 3, the treatment tank 2 is filled with sludge containing anaerobic microorganisms. The anaerobic microorganisms form the sludge into granules by their own activity. Therefore, the portion containing the sludge is the granule layer S. Further, at the bottom of the treatment layer 2, a supply port 3 for supplying raw water containing an organic substance into the treatment tank 2 is provided.
A raw water pipe 4 communicating with a raw water tank (not shown) is connected to. Raw water is jetted from the above-mentioned supply port 3 toward the upper part of the processing tank 2. The flow velocity of the raw water at this time is set to 0.3 to ¹ m ³ / m ² / hr.

By jetting raw water from the bottom of the treatment tank 2 as described above, a granular sludge is developed,
The sludge in the treatment tank 2 is agitated vertically. By stirring the sludge, the anaerobic microorganisms contained in the sludge maintain their activity while maintaining good granules having a particle size of 0.3 to 3 mm. Then, the raw water passes through the granule layer S to decompose organic substances and become treated water. The treated water forms a treated water layer W on top of the granule layer S. Into this treated water layer W, the outflow port 5
The treated water is introduced from the outlet 5 to the treated water pit 7 through the outflow pipe 6. As described above, the raw water can be treated by the anaerobic microorganisms contained in the granule layer S of the treatment tank 2.

Further, in the conventional example as described above, the inclined plate 8 is provided at a position lower than the outflow port 5 above the processing tank 2. The inclined plate 8 is composed of inclined plates 8a and 8b having different angles. These inclined plates 8a and 8b are made to overlap in the vertical direction. In the above-mentioned structure, when granule sludge spreads from the bottom of the treatment tank 2 and a part of the sludge floats up, the granule collides with the inclined plates 8a, 8b. In this way, the granules are inclined plate 8
The granules can be prevented from flowing out of the outlet 5 by hitting a and b, for the following reasons.

That is, when an anaerobic microorganism decomposes an organic substance, methane gas is generated along with this decomposition.
The generated methane gas may adhere to the granules. When the methane gas adheres to the granules in this way, the granules float. When the granules float to the vicinity of the outflow port 5, the granules flow on the treated water and flow out from the outflow port 5.

However, by providing the inclined plates 8a and 8b and ejecting the granules toward the inclined plates 8a and 8b, the rising granules can be lifted.
It hits a and b. Then, due to this impact, the methane gas is separated from the granules. The separated methane gas moves upward along the inclined plates 8a and 8b to form a gas layer G on the upper part of the treated water layer W. On the other hand, the granules will fall downward due to their own weight.

As described above, the methane gas is separated from the granules, and the granules are prevented from flowing out from the outlet 5. Since the granules can be held in the treatment tank 2 without flowing out from the outlet 5, it is not necessary to supplement the shortage of granules in the treatment tank 2 and it is not necessary to prepare sludge for supplementation. Good. In addition, it is possible to save the labor of the above replenishment.

Further, in the conventional apparatus body 1 described above, the treated water flowing out to the treated water pit 7 is sent to the circulation pipe 10 by using the circulation pump 9. The circulation pipe 10 is connected to the raw water pipe 4 so that a part of the treated water is again jetted from the supply port 3. The reason why the treated water is jetted again from the supply port 3 is that the minimum amount of liquid is jetted from the supply port 3 to prevent the supply port 3 from being blocked even when the inflow of raw water is stopped. In addition, the sludge near the supply port is constantly expanded.

Further, in the gas layer G of the apparatus body 1,
As described above, the methane gas is filled, but this methane gas is burned by a combustion device (not shown), and the heat of this combustion keeps the treatment tank 2 at 35 to 37 ° C. This temperature is a suitable temperature for maintaining the activity of anaerobic microorganisms.

[0010]

In the conventional apparatus body 1 as described above, the raw water is supplied to the treatment tank 2. When the BOD of the raw water is a high concentration of, for example, 10000 mg / L or more. However, the formation of granules becomes insufficient. It is believed that dispersible methanogens, which are difficult to form granules, easily grow under high concentration of BOD, and as a result, formation of good granules having a particle size of 0.3 to 3 mm is insufficient. Is.

Further, when the BOD of the raw water is high,
Especially, in the vicinity of the supply port 3, since the raw water is hardly diluted, the BOD concentration remains high. Therefore,
In the vicinity of the supply port 3, good granules having a particle size of 0.3 to 3 mm are not formed. In the vicinity of the supply port 3, fine granules having a particle size of 0.1 mm or less are formed, or no granules are formed at all and the sludge has high dispersibility. These sludges having a fine particle diameter and sludges having high dispersibility are easily rolled up even with a slight flow velocity and easily flow out together with the treated water.

Therefore, when the BOD of the raw water is high, the raw water is diluted before use.

However, when the raw water is diluted and used as described above, the amount of water to be treated naturally increases. When the amount is large, there is a problem that the processing time becomes long. On the other hand, if an attempt is made to process the processing without increasing the processing time, there arises a problem that the size of the processing tank 2 must be increased.

The object of the present invention is to increase the treatment time without increasing the treatment time, even if the BOD of the raw water has a high concentration.
Moreover, it is an object of the present invention to provide an anaerobic water treatment device which does not lead to an increase in size of the device.

[0015]

The present invention is provided with a treatment tank loaded with granules of anaerobic microorganisms, and the raw water containing organic substances is supplied from a feed port provided at the bottom of the treatment tank. In an anaerobic water treatment apparatus which treats the treated water through the granule layer and causes the treated water to flow out from the outlet of the treatment tank. It is characterized in that they are arranged in the depth direction.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION As described in the above-mentioned conventional example, when the BOD concentration of the raw water is too high, it is difficult to form good granules. On the other hand, if the BOD concentration is too low,
Since there is not enough organic matter to be assimilated and decomposed by the microorganisms, the activity of the microorganisms is reduced, and thus granules are less likely to be formed. In the case of the above-mentioned conventional example, the BOD concentration is too high to form good granules at the bottom of the treatment tank, and the BOD is not sufficiently supplied at the top of the treatment tank to reduce the concentration, resulting in good granules. I thought that Le was not formed.

Then, by supplying the raw water by dividing the granule layer from the bottom and the top,
It was speculated that not only the OD concentration could be reduced, but also sufficient BOD could be supplied to the upper part of the granule layer, and good granules could be formed at both the bottom part and the upper part of the granule layer. Therefore, based on the above assumptions, the following experiments were conducted.

(Experiment 1) As an experimental device, a diameter of 150 mm,
Using a transparent vinyl chloride UASB treatment tank having a height of 3 m, experiments were conducted on the following three series. Granules were loaded to a height of 2 m from the bottom of the treatment tank. Further, an inclined plate is provided on the upper part of the granule layer as in the conventional example, and an outlet for discharging treated water is provided on the upper part of the inclined plate.

The above granules are the same as those used in the conventional example. The amount of sludge retained in the treatment tank at this time was 2 kg. As raw water, BOD 20000 mg / L decanter drainage drained in the potato starch production process was used. The treatment tank is provided with a supply port for supplying raw water. A treated water pipe is connected to a supply pipe connected to the supply port so that the raw water and the treated water are mixed and supplied. .

In Series 1, a supply port was provided only at the bottom of the treatment tank, and undiluted raw water was supplied from the above supply port at a flow rate of 50 L / d. In addition, the flow velocity of the raw water is 1 m ³ / m ² /
The treated water was mixed so that the time would be hr. In series 2,
Similar to the series 1, the supply port was provided only at the bottom of the reaction tank.
Then, the raw water was diluted 4-fold to adjust the BOD to 5000 mg / L, and this was passed through the supply port at a water flow rate of 20 L / d. At this time, the treated water was mixed in the supply port so that the flow rate was 1 m ³ / m ² / hr. In Series 3, the bottom of the processing tank,
Supply ports were provided at two places, 1 m above the bottom. Then, the undiluted raw water is passed through each of the supply ports at a volume of 25 L.
Water was passed at / d. At this time, the treated water was mixed at a flow rate of 1 m ³ / m ² / hr.

In each of the above series, the BOD load was 1 kg-VSS / d, and the amount of BO per amount of sludge in the initial stage of operation was
The D load was 0.5 kg / kg-VSS / d. In addition, the pH in the reaction tank is set to the range of 7.2 to 7.5, and the water temperature in the tank is set to 35.
Adjusted to ~ 37 ° C. Then, it was continuously operated for 4 weeks under the above conditions, and the change in the interface of the granule layer was measured. The result is shown in FIG.

As shown in FIG. 1, in each series, the interface tended to decrease until about 10 days after the operation, but in series 1, the interface continued to decrease. It is considered that this is because the granules were not sufficiently formed. If the above granules are not sufficiently formed, sludge that has not formed granules is dispersed in the treatment tank in a fine state, and the dispersed sludge flows out from the outlet. Therefore, if the granules are not sufficiently formed, the interface of the granule layer is lowered. In addition, as a result of measuring the sludge retention amount after 25 days of operation in the above series 1, it was 1.8 kg-VSS, which means that 0.2 kg-VSS sludge was reduced compared to 2 kg-VSS at the beginning of operation. I understand.

In series 2 and 3, the interface gradually rises after 10 days of operation, which suggests that sufficient granules are formed. Furthermore, series 2, 3
As a result of measuring the sludge retention amount after 25 days of operation,
6kg-VSS, 0.06 compared to 2kg-VSS at the beginning of operation
It can be seen that kg-VSS sludge is increasing.

From the above results, when high-concentration raw water is supplied only from the bottom of the treatment tank as in the conventional example, the granules are not sufficiently formed and the sludge may flow out of the treatment tank. I understand. However, when the supply ports are provided at two positions in the depth direction of the treatment tank and the high-concentration raw water is separately supplied from the two supply ports, as in the case where the high-concentration raw water is diluted, It can be said that the granules can be sufficiently formed.

That is, by providing two supply ports in the depth direction of the treatment tank and supplying the raw water from above the treatment tank, it is possible to eliminate the shortage of raw water above.
In this way, the lack of raw water above can be resolved, and the microbial activity above this can be increased. When microorganisms are activated in the upper part of the treatment tank to form granules, the granules fall by their own weight to decompose organic substances in the raw water at the bottom and lower the BOD at the bottom. Therefore, the microorganisms in the entire processing tank can be activated. Then, granules are formed by these activated microorganisms. Since the granules are agitated in the treatment tank by the flow velocity of the raw water supplied from the supply port, there is no shortage of granules in the upper portion of the treatment tank.

FIG. 2 shows an embodiment constructed on the basis of the above results. FIG. 2 is a schematic diagram showing the apparatus main body 11 of one embodiment of the present invention. The illustrated cylindrical processing tank 12 has a height of about 10 m. The treatment tank 12 is provided with three supply ports 13 a, 13 b, 13 c for supplying raw water containing organic substances into the treatment tank 12 in the depth direction of the treatment tank 12. The first supply port 13a is provided at the bottom of the processing tank 12, and the second supply port 13b is provided 2m above the first supply port 13a. Furthermore, this second supply port 13b
The third supply port 13c is provided 2 m above.

The first to third supply ports 13a to 13c are formed in an annular shape and are provided so as to be parallel to each other. In addition, the first to third supply ports 13a to 13c
Is connected to a raw water tank (not shown) via a raw water pipe 14. First to third supply ports 13a to 13 as described above
Raw water is jetted from c to the upper part of the treatment tank 12.

Except that the above-mentioned supply ports are provided at three places,
This is similar to the conventional example. The same reference numerals as those in the conventional example are used for the same components as those in the conventional example. The detailed description of the same components as those of the conventional example will be omitted.

As described above, the first to third supply ports 13a to 1
Since 3c is provided at three positions in the depth direction of the processing tank 12, it is possible to prevent the BOD concentration in the processing tank 12 from being biased. Therefore, it can be prevented that the BOD is very high at the bottom of the treatment tank, but its concentration is low at the top, so that the activity of the microorganism is lowered, as in the conventional example.

As described above, in this embodiment, raw water can be efficiently decomposed. Therefore, BO of raw water
Even if D has a high concentration, it can be decomposed efficiently, so that this raw water does not need to be diluted. Since the raw water does not have to be diluted, the total amount of the treated amount does not increase. Therefore, when the BOD of the raw water has a high concentration, it is possible to eliminate the inconvenience that the entire apparatus becomes large and the processing time becomes long.

Further, by supplying the BOD of the raw water at a high concentration, the dilution water amount becomes insoluble or can be greatly reduced, and the water passage amount can be reduced. Therefore, the amount of methane gas per amount of water flow increases. In other words, the ratio of the amount of methane gas per unit amount of water becomes high. Since the amount of methane gas is increased in this way, the raw water and the treatment tank can be efficiently heated by the amount of heat obtained by burning the generated methane gas. When diluted with raw water as in the conventional example,
Since the amount of methane gas per amount of passing water becomes small, it was difficult to keep the treatment tank at an appropriate temperature of about 35 ° C. only with this heat amount. Therefore, in the case of the conventional example, the treatment tank must be heated by using kerosene in addition to the methane gas.

However, in this embodiment, since a large amount of methane gas can be obtained per amount of water passed, the treatment tank 12 can be heated accordingly. Therefore, it is not necessary to use another energy such as kerosene, so that not only the cost can be reduced but also the energy saving effect can be exhibited.

In the above embodiment, there are three water supply ports, but any number of water supply ports may be provided as long as there are two or more water supply ports. Further, the flow rate of the raw water supplied from the first to third water supply ports 13a to 13c and the flow velocity can be appropriately changed depending on the BOD of the raw water at that time and the like. Also,
First water supply port 13a, second water supply port 13b, second water supply port 13
The distance between b and the third water supply port 13c is set to 2 m, but this does not have to be 2 m and may be changed according to the size of the processing tank 12.

[0034]

According to the present invention, since the supply ports are provided at two or more places and these supply ports are arranged in the depth direction of the processing tank, the raw water is supplied only to a part of the processing tank. It is possible to prevent such inconvenience. Therefore, good granules can be stably formed, and as a result, reduction of granule sludge can be prevented. Further, since it is not necessary to dilute the raw water, it is possible to prevent an increase in the amount of treatment due to dilution, it is possible to shorten the treatment time, and it is possible to prevent the size of the entire apparatus from increasing.

[Brief description of drawings]

FIG. 1 is a graph showing the height of a sludge interface in Experiment 1.

FIG. 2 is an overall view of a device body according to an embodiment of the present invention.

FIG. 3 is an overall view of a conventional apparatus body.

[Explanation of symbols]

11 Device body 12 treatment tanks 13a First supply port 13b Second supply port 13c Third supply port S granule layer

Claims (2)

[Claims] 1. A treatment tank loaded with granules of anaerobic microorganisms is provided, and while the raw water containing organic substances is supplied from a supply port provided at the bottom of the treatment tank, the raw water is passed through the granule layer. In the anaerobic water treatment device that treats the treated water and causes the treated water to flow out from the outlet of the treatment tank, the above-mentioned supply ports are provided at two or more places, and these supply ports are arranged in the depth direction of the treatment tank. Anaerobic water treatment equipment. 2. The anaerobic water treatment device according to claim 1, wherein the plurality of supply ports are arranged substantially parallel to each other.