JPH0947762A - Membrane module for waste water treatment and waste water treatment device and waste water treatment using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To inhibit reduction in permeation flux, etc., by preventing foreign matter such as waste thread from clinging to the membrane module disposed in a biological treatment vessel. SOLUTION: This membrane module consisting of three stage membrane units is constructed by connecting three membrane units 11 to each other in the vertical direction and each of the membrane units 11 comprises plural hollow fiber membranes 13 provided so as to be stretched between two water collecting pipes 12 placed apart right and left from each other. The water collecting pipes 12 of the upper stage membrane unit 11 are connected to a suction pump 15 through a pipeline 14 and the lower stage membrane unit 11 is provided attachably and detachably with a foreign matter capture means 17 by using a coupler 16. At this time, an example of the foreign matter capture means 17 is a unit in which a number of pieces of a threadlike material 19 are stretched between right and left supporting plates 18 in a 10 to 200 pieces/cm<3> density, or the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a permeate and a retentate containing a suspended component having a particle size of at least a predetermined particle size, a wastewater containing colloidal dispersed particles such as bacterial cells, a particle component such as a polymer or an organic substance such as an enzyme. The present invention relates to a membrane module that separates into two.

[0002]

2. Description of the Related Art Biological treatment of household wastewater such as toilets, washrooms, baths and kitchens and industrial wastewater,
Japanese Patent Publication No. 6-98251 discloses a wastewater treatment device which separates the treated wastewater into a retentate containing a turbid component and a permeate (filtrate) in a membrane module.

Further, an aeration device is provided in the wastewater treatment tank,
Japanese Patent Laid-Open No. 1-245894 discloses a wastewater treatment device in which wastewater is circulated in a treatment tank by this aeration device and a hollow fiber membrane is arranged as a membrane module in the middle of this circulation flow.

Further, there is a wastewater treatment apparatus in which a filter is provided upstream of the biological treatment tank separately from the biological treatment tank, and a removing device for removing large contaminants is provided upstream of the filter in Japanese Patent Laid-Open No. 62-74498. It is disclosed in the publication.

[0005]

The wastewater contains pulp and hair, and particularly the laundry wastewater contains relatively long lint and the like. When these fibrous contaminants are entangled with the membrane module, the flow of waste water on the membrane surface is obstructed, and the membrane filtration characteristics are deteriorated. That is, of the wastewater treatment devices described above,
JP-B-6-98251 or JP-A-1-2458.
In the wastewater treatment device disclosed in Japanese Patent Publication No. 94, since the foreign matter removing means is not provided, as shown in FIG. 12, the aeration device provided at the bottom of the biological treatment tank spreads the lint in the wastewater. It is lifted up and is entangled with the lower end of the membrane module, resulting in deterioration of membrane filtration characteristics.

On the other hand, the above-mentioned wastewater treatment apparatus has been disclosed in Japanese Patent Laid-Open No. 1-22.
The filter or the residue removing device disclosed in Japanese Patent No. 45894 can be combined, but it is disclosed in Japanese Patent Laid-Open No. 1-258989.
According to Japanese Patent Laid-Open No. 4, the removal device or the like is arranged as a device separate from the processing tank in the preceding stage of the processing tank, and the wastewater passes through the removal device only once. Therefore, the impurities that could not be trapped well are directly entangled in the membrane module, leading to deterioration of the membrane filtration characteristics.

[0007]

Means for Solving the Problems In order to solve the above problems, a wastewater treatment membrane module according to the present invention is arranged in a tank for biologically treating wastewater, and captures contaminants in the wastewater circulating in the tank. The foreign matter capturing means is provided.

Examples of the membrane module include one in which a plurality of hollow fiber membranes or tubular membranes are stretched between supports having at least one of which is a water collecting pipe out of supports which are separated from each other in the left and right directions or a flat plate-like membrane. preferable. In particular, in the case of the hollow fiber membrane, even if the hollow fiber membrane is damaged, the untreated wastewater does not flow out to the secondary side because the suspended component enters into the damaged portion to block the hole.

Further, if the foreign matter capturing means is detachably attached to the lower portion of the membrane module, maintenance such as periodical replacement becomes easy.

The foreign matter capturing means may be a bundle of filaments, a mesh screen or a brush. When a bundle of filaments is used, the density thereof is 1 to 200.
The number is preferably book / cm3. This is because if it is less than 1 line / cm ³ , the contaminants easily pass between the bundles of filaments, and if it exceeds 200 lines / cm ³ , clogging is likely to occur due to the turbid component, and the optimum range is 10 to 10. 50 pieces / cm ³ For the same reason, the mesh size of the mesh screen is preferably (hole diameter) 0.1 to 20 mm, and the optimum range is 1 to 10 mm.

On the other hand, the wastewater treatment apparatus according to the present invention comprises wastewater circulation means such as an aeration device for circulating the wastewater in the treatment tank, and the upstream side of the membrane module immersed in the treatment tank with the circulating wastewater as a reference. The foreign matter trapping means for trapping foreign matters in the wastewater is arranged in the above.

Here, as the waste water circulation means, an aeration device arranged below the membrane module can be considered, and the aeration device can be equipped with a foreign matter trapping means for trapping foreign matters in the waste water.

Further, the wastewater treatment method according to the present invention comprises a step of biologically treating the wastewater and a step of separating the wastewater after the biological treatment into a permeate and a retentate containing a turbid component having a predetermined particle size or more. Therefore, a wastewater circulation process for circulating the wastewater and capturing impurities is incorporated in the preceding stage of the separation process.

Here, the circulation flow velocity in the waste water circulation step is preferably 0.1 m / sec or more and 2.0 m / sec or less. This is because if the circulation flow rate is less than 0.1 m / sec, the circulation time must be long to capture the contaminants, and the volume of the circulation tank for capturing the contaminants becomes large. On the other hand, if it exceeds 2.0 m / sec, the flow velocity becomes too fast, and there is a risk that impurities will pass through the impurities capturing means.
Therefore, the circulation flow rate is preferably within the above range.

[0015]

By operating the aeration device and the like, the waste water in the treatment tank is circulated and biologically soluble BOD is immobilized in the treatment tank and nitrification of ammonia is performed. On the other hand, the wastewater circulation flow is separated into a permeate and a retentate containing suspended matter having a predetermined particle size or more by coming into contact with the membrane module. Further, since a contaminant capturing means is provided in the circulation path, lint waste, etc. Even if it fails to capture the foreign matter once, it is surely caught during several cycles.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is a cross-sectional view of a wastewater treatment apparatus incorporating the membrane module according to the present invention, FIG. 2A is a front view of the membrane module according to the present invention, and FIG. 2B is a side view of the membrane module. .

The wastewater treatment apparatus 1 has a large-sized foreign matter removal tank 3, a flow rate adjustment tank 4, a reaction treatment tank 5 and a sludge storage tank 6 defined by partition walls 2 ... The organic wastewater W is supplied to the tank 3 through the inflow pipe 7, is admitted to the next chamber through the advection pipe 31, and the disinfection tank 8 is provided above the sludge storage tank 6. The treated wastewater W that has been disinfected is discharged to the outside through the discharge pipe 9.

Further, the membrane module 1 is provided in the reaction treatment tank 5.
0 is immersed. This membrane module 10 is shown in FIG.
As shown in (a) and (b), the membrane unit 1 is vertically arranged.
1 is connected in three stages, and each membrane unit 11 is configured such that a plurality of hollow fiber membranes 13 are stretched between water collecting pipes 12 and 12 which are separated from each other on the left and right, and the water collecting pipes 12 and 1 of the upper membrane unit 11 are arranged.
2 is connected to a suction pump 15 through a pipe 14, and a contaminant capturing means 17 is detachably attached to the lower membrane unit 11 by a coupler 16.

In the illustrated example, the left and right water collecting pipes 12,
The hollow fiber membrane 13 is stretched in the lateral direction by using 12 as a support, but the water collecting pipes 12 and 12 may be arranged separately in the vertical direction and the hollow fiber membrane 13 may be stretched in the vertical direction. Furthermore,
One of the water collecting pipes, which are separated from each other in the left and right direction or the upper and lower direction, may be used as a support made of a pipe or a rod, instead of the water collecting pipe.

As the foreign matter capturing means 17, the filaments 19 are stretched between the left and right support plates 18 and 18 at a density of 1 to 200 threads / cm ³ as shown in FIGS. 2 (a) and 2 (b). , A mesh screen 20 having a hole diameter (mesh size) of 0.1 to 20 mm as shown in FIGS. 3 (a) and 3 (b), or FIG.
It is conceivable that a rod-shaped brush 21 is attached between the support plates 18, 18 as shown in (a) and (b). In this way, if the contaminant capturing means 17 is attached to the lower membrane unit 11 by using the coupler 16, the contaminant capturing means 17 can be used in accordance with the type of waste water, such as the filament 19, the mesh screen 20 or the rod shape. The brush 21 or the like can be arbitrarily selected and replaced.

On the other hand, an aeration device 22 is arranged below the membrane module 10, and air is sent to the aeration device 22 through a blower 23 and a pipe 24. Then, by intermittently operating the aeration device 22, the aerobic treatment and the anaerobic treatment are repeatedly performed in the reaction treatment tank 5.

That is, in the aerobic treatment, ammonia nitrogen (NH4 ⁺ ) in the wastewater is oxidatively decomposed into nitrate nitrogen (NO3 ⁻ ) and nitrite nitrogen (NO2 ⁻ ), and in the anaerobic treatment, the anaerobic treatment is anaerobic. The denitrifying bacteria use organic carbon to reduce these nitrate nitrogen (NO3 ⁻ ) and nitrite nitrogen (NO2 ⁻ ) and convert them to nitrogen gas (N ₂ ).

5 to 7 are views showing another embodiment,
In the embodiment shown in FIG. 5, a flat plate-shaped membrane 30 is applied as the membrane module 10, an aeration device (air diffuser pipe) 22 is attached to the lower end of the flat-plate-shaped membrane 30 via a support rod 31, and further a support rod. A mesh screen 20 as a foreign matter capturing means is attached to an intermediate portion of 31.

In the embodiment shown in FIG. 6, cylindrical partition walls 32 are arranged in the reaction treatment tank 5 in the vertical direction, the membrane module 10 is arranged inside the partition walls 32, and the partition walls 32 are further arranged.
A plurality of air diffusers (aeration device) 22 connected to the blower 23 are provided inside the membrane module 10, and the air diffusers 2 are provided.
A bar-shaped brush 21 as a foreign matter capturing means 17 is attached to the unit 2.

In the embodiment shown in FIG. 7, a support plate 18 is attached to the lowermost membrane unit 11 via a coupler 16, and a rod-shaped brush 21 as a foreign matter capturing means 17 is provided between the left and right support plates 18. Attached, and the left and right support plates 18
An air diffuser (aeration device) 22 is attached to the lower end of the. In this way, by integrating the membrane unit 11, the foreign matter capturing means 17, and the aeration device 22, the setting in the reaction treatment tank 5 can be easily performed.

8 to 10 are cross-sectional views of a wastewater treatment apparatus provided with a foreign matter capturing means as a separate body from the membrane module. Among these, in the wastewater treatment device shown in FIG. 8, two membrane modules 10 are arranged in the reaction treatment tank 5, and a stirring pump 25 for forming a circulation flow of the wastewater W is installed in the reaction treatment tank 5. , Each membrane module 1 based on the circulating waste water
0 Contaminant capturing means 1 for capturing contaminants in wastewater on the upstream side 1
7 are provided.

On the other hand, in the wastewater treatment device shown in FIG. 9, the aeration device 22 is used as the wastewater circulation means and the reaction treatment tank 5 is used.
It is installed at the bottom of the membrane, is a circulation route of wastewater, and is a membrane module 10.
The foreign matter capturing means 17 is disposed on the upstream side of the. With such a configuration, the number of parts can be reduced.

Further, in the waste water treatment apparatus shown in FIG. 10, a circulation type foreign matter removing tank 40 is provided separately from the reaction processing tank 5.
And a cylindrical partition wall 32 is arranged in the reaction treatment tank 5, a membrane module 10 composed of a plurality of flat plate-shaped membranes 30 is arranged in the cylindrical partition wall 32, and the cylindrical partition wall 32 is arranged below the membrane module 10. By arranging the aeration device 22 connected to the blower 23 inward, the inside of the cylindrical partition 32 is provided with an upward flow path for wastewater,
The outside is used as a downward flow channel for wastewater. The membrane module 10 is not limited to the flat plate-shaped film 30, but when a plurality of flat plate-shaped films 30 are arranged in parallel in the vertical direction, it is preferable that the distance between the films is 5 mm or more and 10 mm or less.

Further, the aeration device 22 connected to the blower 23 is also arranged at the bottom of the foreign matter removing tank 40 to form a circulating flow of waste water, and the central portion of the foreign matter removing tank 40 in the middle of this circulating flow. A foreign matter trapping means 17 such as a mesh screen is provided from above. Then, the wastewater from which the contaminants are removed by the contaminant capturing means 17 is sent into the reaction treatment tank 5 through the pipe 41.

[0030]

FIG. 11 shows the waste water treatment apparatus according to the present invention shown in FIG. 1, the waste water treatment apparatus provided with the foreign matter trapping means outside the treatment tank, and the waste water treatment apparatus not provided with the foreign matter trapping means. It is a graph showing the relationship between the number of days elapsed and the permeation flux, as is clear from this figure, like the wastewater treatment membrane module according to the present invention, a contaminant capturing means for capturing contaminants in the wastewater, By installing in the membrane module,
Contaminants such as lint are not entangled in the membrane module, and the decrease in permeation flux with time is reduced.

Further, when the hollow fiber membrane is used as the membrane module, even if the hollow fiber membrane is damaged, suspended matter will enter the damaged portion to block the hole, and the untreated wastewater will not flow out to the secondary side. .

Further, if the foreign matter capturing means is detachably attached to the lower portion of the membrane module, maintenance such as periodical replacement can be facilitated, and when a bundle of filaments is used as the foreign matter capturing means. , Density 1-200 /
By setting it to cm ³ , it is possible to reliably prevent foreign substances from being clogged while capturing foreign substances. Further, when the mesh screen is used as the contaminant capturing means, for the same reason, the mesh size of the mesh screen is (hole diameter) 0.1 to 20 mm while capturing the contaminant, Prevents clogging.

Further, the contaminants for capturing the contaminants in the wastewater are provided upstream of the membrane module immersed in the treatment tank on the basis of the wastewater circulating through the contaminant capturing means without attaching the contaminant capturing means to the membrane module. By arranging the capturing means, the same effect as described above is exhibited. If the aeration device is used as the circulation means, the number of parts can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a wastewater treatment device incorporating a membrane module according to the present invention.

FIG. 2 (a) is a front view of a membrane module according to the present invention,
(B) is a side view of the membrane module

3A is a front view of a membrane module according to another embodiment, and FIG. 3B is a side view of the membrane module.

4A is a front view of a membrane module according to another embodiment, and FIG. 4B is a side view of the membrane module.

5A is a front view of a membrane module according to another embodiment, and FIG. 5B is a side view of the membrane module.

FIG. 6 is a front view of another embodiment in which an aerator and foreign matter capturing means are integrated.

FIG. 7 (a) is a front view of another embodiment in which an aerator, foreign matter capturing means and a membrane module are integrated, and FIG. 7 (b) is a side view thereof.

FIG. 8 is a cross-sectional view of a wastewater treatment device provided with a contaminant capturing means as a separate body from the membrane module.

FIG. 9 is a diagram showing another embodiment of the wastewater treatment device shown in FIG.

FIG. 10 is a diagram showing another embodiment of a wastewater treatment device in which a biological reaction tank and a contaminant removal tank are separated.

FIG. 11 shows the elapsed days and the permeation flux of the wastewater treatment apparatus according to the present invention shown in FIG. 1, the wastewater treatment apparatus provided with foreign matter trapping means outside the treatment tank, and the wastewater treatment apparatus not provided with foreign matter trapping means. Graph showing the relationship with

FIG. 12 is a sectional view of a conventional wastewater treatment device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Wastewater treatment device, 3 ... Large foreign substance removal tank, 4 ... Flow control tank, 5 ... Reaction processing tank, 6 ... Sludge storage tank, 10 ... Membrane module, 11 ... Membrane unit 11, 12 ... Water collection pipe, 13 ...
Hollow fiber membrane, 16 ... Coupler, 17 ... Foreign matter capturing means, 1
8 ... Support plate, 19 Filament, 20 ... Mesh screen, 2
1 ... Brush, 22 ... Aeration device, 25 ... Stirring pump, W
… Wastewater.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location C02F 3/02 C02F 3/02 Z (72) Inventor Yuichi Okuno 2 Nakajima, Kokurakita-ku, Kitakyushu, Fukuoka 1-2-1 Totoki Equipment Co., Ltd. (72) Inventor Yuko Fujimoto 2-1-1 1-1 Nakajima, Kokurakita-ku, Kitakyushu City, Fukuoka Prefecture Totoki Equipment Co., Ltd.

Claims (13)

[Claims] 1. A membrane module for wastewater treatment, which is disposed in a tank for biological treatment of wastewater, and which separates the wastewater after biological treatment into a permeate and a retentate containing a turbid component having a predetermined particle size or more. The module for wastewater treatment is characterized in that the module is provided with a contaminant capturing means for capturing contaminants in the wastewater circulating in the tank. 2. The membrane module for wastewater treatment according to claim 1, wherein the membrane module is a flat plate-shaped membrane or a plurality of support bodies having at least one of the support bodies spaced apart from each other in the left-right direction or the top-bottom direction serving as a water collecting pipe. The membrane module for wastewater treatment, which is constructed by stretching the hollow fiber membrane or tubular membrane. 3. The membrane module for wastewater treatment according to claim 1 or 2, wherein the contaminant capturing means is detachably attached to a lower portion of the membrane module. . 4. The membrane module for wastewater treatment according to any one of claims 1 to 3, wherein the contaminant capturing means comprises a bundle of filaments. 5. The wastewater treatment membrane module according to claim 4, wherein the density of the bundle of filaments is 10 to 200 pieces /
A membrane module for wastewater treatment, characterized in that it is cm ³ . 6. The membrane module for wastewater treatment according to claim 1, wherein the foreign matter capturing means is a mesh screen. 7. The membrane module for wastewater treatment according to claim 6, wherein the mesh screen has a mesh size of 1 to
A membrane module for wastewater treatment, which is 20 mm. 8. The membrane module for wastewater treatment according to claim 1, wherein the contaminant capturing means has a brush shape. 9. A membrane module for separating the biologically treated wastewater into a permeate and a retentate containing a suspension component having a predetermined particle size or more is immersed in a treatment tank for biologically treating the wastewater with microorganisms. In the wastewater treatment equipment, this wastewater treatment equipment is equipped with a wastewater circulation means for circulating the wastewater in the treatment tank, and the contaminants in the wastewater are captured on the upstream side based on the circulating wastewater of the membrane module immersed in the treatment tank. A wastewater treatment device, characterized in that a foreign matter trapping means is disposed. 10. The wastewater treatment device according to claim 9, wherein the wastewater circulation means is an aeration device arranged below the membrane module. 11. A membrane module for separating the wastewater after biological treatment into a permeate and a retentate containing suspension components having a predetermined particle size or more is immersed in a treatment tank for biologically treating the wastewater with microorganisms. In the wastewater treatment equipment, this wastewater treatment equipment is equipped with an aerator that feeds air into the wastewater and circulates the wastewater in the treatment tank, and this aeration equipment is provided with a foreign matter trapping means for trapping foreign matter in the wastewater. A wastewater treatment device. 12. A wastewater treatment method comprising a step of biologically treating the wastewater and a step of separating the wastewater after the biological treatment into a permeate and a retentate containing a turbid component having a predetermined particle size or more,
A wastewater treatment method, characterized by incorporating a wastewater circulation step for circulating wastewater and capturing contaminants in the preceding stage of the separation step. 13. The wastewater treatment method according to claim 11, wherein the circulation flow velocity in the wastewater circulation step is 0.1 m / sec or more and 2.0 m / sec or less.