JPH0722749B2 - Sewage treatment equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a sewage treatment apparatus provided with an ultrafiltration membrane.

2. Description of the Related Art In a conventional wastewater treatment device of this type, for example,
As shown in FIG. 9 and FIG. 9, a cylindrical membrane module 3 having an ultrafiltration membrane is horizontally arranged in a plurality of rows on a mounting plate 2 provided in an activated sludge treatment tank 1 (in the figure, Four
Columns) and a plurality of stages (three stages in the figure) are arranged in the vertical direction, and the diffusion tubes 4 are provided at the bottom of the treatment tank 1 for each column of the membrane module 3. A pump 5 and a blower 6 are provided for each row of the membrane module 3, the pump 5 is connected to the outlet side of the membrane module 3 in each row, and the blower 6 is connected to each air diffuser 4. .

Then, the sewage is supplied into the activated sludge treatment tank 1, mixed with the activated sludge in the tank to form a mixed solution 7, and oxidatively decomposed by the microorganisms contained in the activated sludge. On the other hand, the air diffuser 4 is supplied with aeration air from the blower 6 and blows it out as air bubbles into the mixed solution 7, thereby supplying oxygen for growth to the microorganisms in the mixed solution 7 and upwardly flowing into the mixed solution 7. Is generated, and the mixed solution 7 is circulated in the direction of the arrow in FIG. The mixed solution 7 is sucked by the pump 5 through the membrane module 3 and is filtered and separated into concentrated liquid and clean treated water by the membrane module 3. The concentrated liquid remains in the tank and circulates upward, and the treated water is discharged to the outside of the tank. At that time, part of the solid content (so-called SS) in the concentrated liquid adheres to the surface of the membrane module 3 as a scale.
A part of this scale is removed by the upward water flow of the mixed solution 7, but the rest gradually grows and the membrane module 3
Since the ultrafiltration membrane of (3) is clogged, the remaining scale is removed by periodically cleaning the membrane module 3 with a chemical.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention However, in the above conventional sewage treatment apparatus, when the chemical is directly introduced into the activated sludge treatment tank 1 during the chemical cleaning, the activated sludge microorganisms are killed. Moreover, it is not allowed to suspend the operation of the equipment for cleaning. Therefore, it is necessary to take out the membrane modules 3 out of the tank in units such as row by row for chemical cleaning.
There was a problem that work efficiency was poor and it was not suitable for large-scale equipment.

An object of the present invention is to improve a conventional wastewater treatment device and solve such a problem.

Means for Solving the Problems In order to achieve the above object, the sewage treatment apparatus of the present invention,
An activated sludge treatment tank and a filtration treatment tank are provided separately from each other, the inside of each filtration treatment tank is divided into a plurality of rows of filtration chambers by partition walls, and the upper and lower parts of each filtration chamber are provided with a partition passage. Is connected to the upper and lower parts of the activated sludge treatment tank respectively, and a plurality of membrane modules are arranged in each filtration chamber, and the aeration air is supplied to the bottom of each filtration chamber and this aeration An air diffusing pipe is provided for generating an upward water flow in the filtration chamber by the bubble flow of air and circulating this water flow between the activated sludge treatment tank and the filtration chamber through the upper and lower communication passages. .

Action In the configuration of the present invention, sewage is supplied into the activated sludge treatment tank, mixed with the activated sludge in the tank to form a mixed solution, and oxidatively decomposed by the microorganisms contained in the activated sludge. . On the other hand, the air diffuser is supplied with aeration air from a blower and blows out as air bubbles into the mixed solution in each filtration chamber, thereby supplying oxygen for growth to the microorganisms in the mixed solution and causing an upward water flow to the mixed solution. Occur. This mixed solution ascends in the filtration chamber, flows into the activated sludge treatment tank through a communication passage such as an upper communication pipe or a weir, mixes with the mixed solution in the activated sludge treatment tank, and descends. By flowing into each of the filtration chambers via the communication passage of, the circulation between the activated sludge treatment tank and the filtration treatment tank is achieved. Therefore, not only the activated sludge treatment tank but also the filtration treatment tank will be provided with a biological treatment function. For biological treatment, the activated sludge treatment tank and the filtration treatment tank will be installed side by side. Since each of them will share the processing, it becomes possible to adjust and control the respective volume ratio, circulating liquid amount, etc. according to the processing purpose. Then, when the mixed solution rises in each filtration chamber, it is sucked by the pump through the membrane module, and is filtered and separated into a concentrated liquid and clean treated water by the membrane module. The concentrated liquid remains in the filtration chamber and ascends and circulates together with the mixed solution, and the treated water is taken out of the filtration chamber via the inside of the membrane module. During the above-mentioned filtration separation, the scale attached to the surface of the membrane module is partially removed by the upward flow of the mixed solution, but the rest is removed by periodical chemical cleaning in each filtration chamber as described below. To be done.

That is, first, a partition device such as a valve in the upper and lower communication passages between the filtration chamber to be cleaned and the activated sludge treatment tank is closed, the filtration chamber is shut off from the activated sludge treatment tank, and the other filtration chambers are Leave it as it is and continue operation. Next, the filter chamber to be cleaned is filled with tap water and rinsed with water, the mixed liquid after the rinse is drained, and if necessary, the cleaning liquid is put into the chemical tank and the cleaning liquid is put into the filter chamber and chemicals by a cleaning pump. The membrane module is washed by circulating it with the tank, and when the washing is completed, the partitioning devices such as the upper and lower valves are opened to return to the normal operating state. The membrane modules in the other filtration chambers are also washed in the same manner as above. As described above, according to the configuration of the present invention, chemical cleaning of the membrane module is possible without completely stopping the operation of the equipment and without removing the membrane module.

Embodiment An embodiment of the present invention will be described below with reference to FIGS. 1 to 7.

The sewage treatment apparatus of this embodiment comprises an activated sludge treatment tank 11 and a filtration treatment tank 12, as shown in FIGS. 1 and 2. The inside of the filtration treatment tank 12 is divided by a partition wall 13 into a plurality of rows (four rows in the figure) of filtration chambers 14, and both upper and lower parts of each filtration chamber 14 are provided with valves 15 as partitioning devices. It is connected to both upper and lower parts in the activated sludge treatment tank 11 via a communication pipe 16 provided as a communication passage. Inside each filtration chamber 14 is a cylindrical membrane module 17 with a filtration membrane.
Are stacked vertically (three in the figure) and an air diffuser 18 is provided at the bottom. Furthermore, a pump 19 and a blower 20 are provided for each filtration chamber 14, the pump 19 is connected to the outlet side of the membrane module 17 in each filtration chamber 14, and the blower 20 is connected to each air diffuser 18. There is.

Next, the operation of the above configuration will be described.

Sewage is supplied into the activated sludge treatment tank 11, is mixed with the activated sludge in the tank to form a mixed solution 21, and is oxidatively decomposed by microorganisms contained in the activated sludge. Meanwhile, the air diffuser 18
Is supplied with aeration air from the blower 20, by blowing out into the mixed solution 21 in each filtration chamber 14 as air bubbles, while supplying oxygen for growth to the microorganisms in the mixed solution 21 and upward of the mixed solution 21. Generate a stream of water. This mixed solution 21
Rises in the filtration chamber 14, flows into the activated sludge treatment tank 11 via the upper communication pipe 16, mixes with the mixed solution 21 in the activated sludge treatment tank 11 and descends, and lower communication pipe By flowing into each filtration chamber 14 via 16, it circulates between the activated sludge treatment tank 11 and the filtration treatment tank 12 in the arrow direction in FIG.
Therefore, not only the activated sludge treatment tank 11, but also the filtration treatment tank 12 is provided with a biological treatment function, and regarding the biological treatment, these activated sludge treatment tanks 11 and the filtration treatment are provided together. Since each of the tanks 12 will share the processing, it becomes possible to adjust and control the volume ratio of each, the amount of circulating liquid, etc. according to the processing purpose.

Then, the mixed solution 21 is sucked by the pump 19 through the membrane module 17 when rising in each filtration chamber 14,
The membrane module 17 filters and separates the concentrated liquid and the clean treated water. The concentrated liquid remains in the filtration chamber 14 and ascends and circulates together with the mixed solution 21, and the treated water is taken out of the filtration chamber 14 via the inside of the membrane module 17. At the time of the filtration separation, part of the scale attached to the surface of the membrane module 17 is removed by the upward water flow of the mixed solution 21, but the rest is removed by periodic chemical cleaning of each filtration chamber 14. This chemical cleaning has two methods as described below.

In the first cleaning method, first, the filtration chamber 14 to be cleaned is
Between the upper and lower communication pipes 16 between the activated sludge treatment tank 11 and the activated sludge treatment tank 11
To shut off the filtration chamber 14 from the activated sludge treatment tank 11, and to remove the liquid in the filtration chamber 14 and empty it, a pipe provided at the bottom of the filtration chamber 14 and a valve 28 of 31 are installed. open. Remove all liquid and close again. Further, before washing the membrane module 17 with chemicals, the valve 29 of the tap water supply pipe 30 is opened to fill the filtration chamber 14 with tap water, and then air is sent from the blower 20 to wash the membrane module. After that, the blower 20 is stopped, and the washing water is drawn out as in the previous case, and the other filtration chamber 14 is left as it is and the operation is continued. next,
As shown in FIG. 3, the bottoms of the filtration chamber 14 and the chemical tank 22 to be cleaned are connected to each other by a chemical communication pipe 23, and a cleaning pump is provided on the outlet side of the membrane module 17 in the filtration chamber 14. 24 is connected, and the discharge pipe 25 of the cleaning pump 24 is returned to the chemical tank 22.

After this, when the cleaning liquid from the chemical tank 22 is filled in the filtration chamber 14 and the cleaning pump 24 is operated, the cleaning liquid 26 in the filtration chamber 14 is moved by the cleaning pump 24 in the direction of arrow A in FIG. It is sucked into 17 and discharged from the pipe 25 to the chemical tank 22.
Return to inside. The cleaning liquid 26 in the chemical tank 22 flows into the filtration chamber 14 via the communication pipe 23. In this way, the cleaning liquid 26
Cleans both the inner and outer surfaces of the membrane module 17 while circulating between the filtration chamber 14 and the chemical tank 22. In addition, the cleaning liquid 26 is circulated in the direction opposite to the above, and the membrane module 17 is moved to the arrow B in FIG.
It is also possible to carry out a so-called backwash in the direction. When the washing is completed, the filtration chamber 14 is returned to the original operating state, and the membrane module 17 in the other filtration chamber 14 is washed in the same manner as above.

Further, in the second cleaning method, first, in the same manner as the first method, the filtration chamber 14 to be cleaned is cut off from the activated sludge treatment tank 11, and the other filtration chambers 14 are left as they are to continue the operation. deep. Next, as shown in FIG. 5, the bottoms of the filtration chamber 14 and the chemical tank 22 to be cleaned are connected to each other by a chemical communication pipe 23 equipped with a cleaning pump 24, and the innermost portion of the filtration chamber 14 is cleaned. One end of the overflow pipe 27 is connected slightly above the upper membrane module 17, and the other end is connected to the chemical tank 22.
I will put it back. Next, the cleaning liquid 26 is put into the filtration chamber 14 to be cleaned from the chemical tank 22, and the cleaning pump 24 is operated.

Then, the cleaning liquid 26 in the chemical tank 22 flows into the filtration chamber 14 via the communication pipe 23. Therefore, the cleaning liquid 26 in the filtration chamber 14
The liquid level rises, flows out from the overflow pipe 27, and returns to the inside of the chemical tank 22. In this way, the cleaning liquid 26 is circulated between the filtration chamber 14 and the chemical tank 22 while the membrane module 17 is being circulated.
Wash the surface of the. At that time, as shown in FIG. 6, a part of the cleaning liquid 26 also functions to clean the membrane module 17 by soaking it in from the surface of the membrane module 17 to the inside. After cleaning, return the filtration chamber 14 to its original operating condition,
The membrane module in the other filtration chamber 14 is washed in the same manner as above. Note that this cleaning method and the first cleaning method may be used together.

As described above, according to the configuration of the present embodiment, by any cleaning method, without completely stopping the operation of the equipment for wastewater treatment, and without removing the membrane module 17, this membrane Module 17 can be cleaned with chemicals.

FIG. 7 shows an upper communication passage and a partition device, instead of the communication pipe 16 and the valve 15 shown in FIG.
33 and a weir 32 provided in this flow path are shown.

As described above, the present invention provides the activated sludge treatment tank and the filtration treatment tank separately from each other, and divides the inside of the filtration treatment tank into a plurality of rows of filtration chambers, and each filtration chamber and the activated sludge treatment. The membrane module is configured so that it can communicate with and cut off from the tank, and the membrane module is installed in each filtration chamber, so the chemicals of the membrane module can be removed without completely stopping the operation of the equipment and without removing the membrane module. Can be washed. Therefore, it can be suitably used for large-scale equipment. Not only that, because the upper and lower parts of each filtration chamber were connected to the upper and lower parts of the activated sludge treatment tank through the communication passage, respectively, the activated sludge treatment tank and the filtration chamber were It is possible to generate a water flow that circulates, and in addition to the activated sludge treatment tank, it is possible to add a biological treatment function to the filtration treatment tank. It becomes possible to share the treatment in each of the sludge treatment tank and the filtration treatment tank,
Adjust each volume ratio and circulating fluid amount according to the processing purpose.
Can be controlled.

[Brief description of drawings]

FIG. 1 is a sectional view of a sewage treatment apparatus showing an embodiment of the present invention, FIG. 2 is a plan view of the apparatus of FIG. 1, and FIG. 3 is an embodiment of a chemical cleaning method for a membrane module according to the present invention. Partially cutaway view, FIG. 4 is an explanatory view showing a cleaning state of the membrane module in FIG. 3, FIG. 5 is a partial cross-sectional view showing another embodiment of the chemical cleaning method for the membrane module in the present invention, and FIG.
5 is an explanatory view showing a cleaning state of the membrane module in FIG. 5, FIG. 7 is a cross-sectional view illustrating a case where the upper partition device is a weir, and FIG. 8 is a cross-sectional view showing an example of a conventional wastewater treatment device, FIG. 9 is a plan view of the device of FIG. 11 …… Activated sludge treatment tank, 12 …… Filtration treatment tank, 13 …… Partition wall, 14 …… Filtration chamber, 15 …… Valve (partitioning device), 16 ……
Communication pipe (communication passage), 17 ... Membrane module, 18 ... Air diffusion pipe, 32 ... Weir (partitioning device), 33 ... Communication passage (communication passage).

Claims (1)

[Claims] 1. An activated sludge treatment tank and a filtration treatment tank are provided separately from each other, and the filtration treatment tank is divided into a plurality of rows of filtration chambers by partition walls, and both upper and lower parts of each filtration chamber are equipped with partitioning devices. Connected to the upper and lower parts of the activated sludge treatment tank respectively, a plurality of membrane modules are arranged in each filtration chamber, while supplying aeration air into the filtration chamber at the bottom of each filtration chamber, An air diffuser is provided to generate an upward water flow in the filtration chamber by the bubble flow of the aeration air and to circulate the water flow between the activated sludge treatment tank and the filtration chamber through the upper and lower communication passages. Sewage treatment equipment to be.