JPH02102793A - Apparatus for treating filthy water - Google Patents

Abstract

PURPOSE:To facilitate pressure control of an apparatus for treating filthy water by installing a membrane separation device to above a cover attached freely closably and openably and connecting a vacuum tank to a collecting pipe for permeated water. CONSTITUTION:Filthy water 1 is aerated by injecting the filthy water into an aeration tank 18 and blowing air through an air diffusing device 4 at the bottom of the aeration tank 18. At the same time, the filthy water is subjected to membrane separation treatment by means of a rotary disc membrane 17. Permeated water is drawn out into a vacuum tank 23 having a pressure control valve 22 which can be operated at a negative pressure using a vacuum pump 21 through a line 20 for treated water, then transferred further with a transfer pump 24 for the treated water. When the treatment is continued for a long time, a gel layer is formed on the surface of the membrane. For the purpose of washing the membrane, the aeration tank 18 is separated into an upper section and a lower section by closing the cover 19, and the washing of the membrane is performed at the upper section. Thus, a fixed pressure is held easily and the membrane is washed without detaching a membrane module.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a sewage treatment device that combines aeration treatment and membrane separation treatment of sewage.

[Conventional technology]

As a conventional device of this type, one in which a membrane separation tank is installed outside the aeration tank is known. For example, as shown in FIGS. 4 and 5, an aeration tank 5 has a mechanism in which the air from a blower 2 is forced through an air pipe 3 and blown out from an aeration device 4. The mixed liquid 7 in the aeration tank 5 is introduced into the membrane separation tank 9 through the circulation piping 8 using the circulation pressure pump 6 while being treated with microorganisms, and the pressure in the membrane separation tank 9 is adjusted with the pressure regulating valve 10. The liquid was subjected to membrane separation treatment, returned to the aeration tank 5 through the circulation pipe 11, and the pressurized mixed liquid was fixed to a hollow shaft 16 that was rotated by a sprocket wheel 14, a chain 15, etc. with the power of a drive device 13. An apparatus is known in which treated water 12 is filtered through a rotating disc membrane 17 and drawn out from a hollow shaft 16.

[Problem to be solved by the invention]

However, in the conventional type of equipment in which a membrane separation tank is installed outside the aeration tank, the installation area and volume are large, and the membrane separation tank must be a pressure-resistant container, which is expensive.
Furthermore, the pressure regulating valve 10 has a drawback in that it is difficult to adjust the pressure to a constant level due to clogging with sludge or the like.

Therefore, the present invention eliminates the drawbacks of the prior art described above, does not require a pressure-resistant container, and can easily adjust to a constant pressure.
The objective is to provide a compact and inexpensive sewage treatment device.

[Means to solve the problem]

The present invention solves the above-mentioned problems by dividing the aeration tank into upper and lower parts, installing a membrane module on the upper part, and configuring the tank to be a depressurization system instead of a pressurization system to facilitate pressure adjustment.

That is, in the sewage treatment apparatus of the present invention, a lid that can be opened and closed is provided in the middle part of the aeration tank, and a membrane separation device having a membrane module for liquid separation and a permeated water collection vibrator is installed above the lid, and the permeated water The water collection pipe is characterized by a vacuum tank that can be used to create negative pressure using a vacuum pump.

〔Example〕

Next, the present invention will be explained in further detail based on embodiments shown in the drawings.

FIG. 1 is a system diagram of a sewage treatment apparatus showing an embodiment of the present invention, and FIG. 2 is a sectional view of the membrane separation section in the upper part of the treatment apparatus of FIG.

In this embodiment, the aeration tank 18 is partitioned in the middle by an openable/closable M19. A large number of rotary disc membranes 17 are fixed to a hollow shaft 16 which functions as a permeated water collection pipe on the upper part of the lid 19.
By rotating 6, the rotating disc membrane 17 also rotates. When processing with this device, wastewater is transferred to the aeration tank 18.
The wastewater is aerated by blowing air through the aeration device 4 at the bottom of the aeration tank 18, and membrane separation is performed using the rotating disc membrane 17 installed at the top. It is drawn out to a vacuum tank 23 having a pressure regulating valve 22 that can be made negative pressure by a vacuum pump 21,
The treated water is further transferred by the treated water transfer pump 24.

If the treatment is carried out for a long period of time using the treatment apparatus shown in FIG. 1, a gel layer may be formed on the membrane surface, which may cause the membrane to become clogged. To prevent this, it is necessary to clean the membrane. When cleaning the membrane, the aeration tank 18 is closed by closing M19.
The membrane is divided into upper and lower sections, and the membrane is washed in the upper section. For example, chemical cleaning using sodium hypochlorite, detergent, etc. is performed, and after completion of cleaning, the cleaning chemical solution is discharged by a drainage device (not shown), and then the lid 19 is opened and wastewater treatment is started again. .

The sewage treatment apparatus shown in FIG. 3 is an embodiment configured so that the sewage treatment process can be continuously operated without stopping the sewage treatment process even during the cleaning process. In this embodiment, the upper part of the aeration tank 25 is divided into two sections by a partition wall 26, the bottom of each section is provided with an openable and closable lid 27, and each section has a large number of rotating disks. A membrane 17 is provided. In this processing apparatus, when cleaning the membrane, the compartment containing the rotating disk membrane 17 to be cleaned is closed by closing the lid 27, and the mixed liquid in this compartment is transferred to the next compartment. A cleaning chemical solution is injected into the empty compartment from the cleaning chemical solution introduction pipe 28.

By transferring the liquid mixture to the other compartment as described above, a back pressure is created in the closed M21, allowing a more complete seal so that the cleaning chemical solution does not leak into the aeration tank.

After the cleaning is completed, the cleaning chemical solution is discharged from the drain pipe 29.

Thus, in the apparatus shown in FIG. 3, during the cleaning process,
In the other compartment, the membrane separation process can be continued with the lid 27 open. Treated water is taken out from treated water line 20.

〔Effect of the invention〕

The sewage treatment device of the present invention has a significantly smaller installation area and volume than conventional devices of this type, does not require a pressure container, and is inexpensive. Furthermore, the processing device of the present invention includes:
Since the pressure reduction method is used instead of the pressurization method, the pressure can be easily adjusted and maintained at a constant pressure.

Furthermore, in the processing apparatus of the present invention, the membrane module can be cleaned without removing it, and the upper part of the aeration tank is partitioned into two or more compartments, and each compartment is provided with a membrane module and a lid. Cleaning can be performed without stopping the process.

[Brief explanation of the drawing]

Fig. 1 is a system diagram of a sewage treatment equipment showing one embodiment of the present invention, Fig. 2 is a sectional view of the membrane separation section of the equipment of Fig. 1, and Fig. 3 is a sewage water treatment equipment showing another embodiment of the present invention. FIG. 4 is a system diagram of a conventional sewage treatment device, and FIG. 5 is a sectional view of a membrane separation tank of the device shown in FIG. 4. Explanation of symbols 1...Sewage, 4...Diffuser, 5.18°25...
・Aeration tank, 9... Membrane separation tank, 16... Hollow shaft, 17
... Rotating disk membrane, 19.27 ... Lid, 20 ... Treated water line, 21 ... Vacuum pump, 22 ... Pressure adjustment valve, 23 ... Vacuum tank, 26 ... Partition wall, 28
...Cleaning chemical solution, 29...Drain pipe Figure 2 Figure 4 Figure 5

Claims (2)

[Claims] (1) A lid that can be opened and closed is provided in the middle of the aeration tank, a membrane separation device having a membrane module for liquid separation and a permeated water collection pipe is installed above the lid, and the permeated water collection pipe has a vacuum A sewage treatment device that is equipped with a vacuum tank that can create negative pressure with a pump. (2) The sewage treatment apparatus according to claim 1, wherein the upper part of the aeration tank is partitioned into two or more compartments, a partition lid that can be opened and closed is provided at the bottom of each compartment, and a membrane separation device is installed in each compartment.