JPH10174986A - Septic tank - Google Patents

Abstract

PROBLEM TO BE SOLVED: To hold uniformly without reducing a rotary flow velocity, to wash efficiently, to prevent clogging, and to improve a filtration-purification capacity by stretching hollow fiber membranes set in a purification tank horizontally. SOLUTION: An aerobic tank body 2 in which hollow fiber membranes 1 are set is installed in a purification tank. The membranes 1 are stretched horizontally by a tension means 3 comprising a spring 6. A diffusion pipe 4 is installed below the membranes 1. The membranes 1 are arranged vertically in parallel at distance from each other. Each membrane 1 is aerated by air ejected from the pipe 4, an ascending agitation flow is generated by water to be treated, and cake layers adherent to the membranes 1 are peeled off to wash the membranes 1. Since the membranes 1 are stretched horizontally, they are prevented from slackening to a vertical sludge rotary flow. Accordingly, the pressure loss of rotary flow sludge and the decrease in a rotary flow velocity can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane separation type septic tank having an aerobic tank in which a hollow fiber membrane is provided, and performing solid-liquid separation in the aerobic tank.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG.
A septic tank having an aerobic tank body 2 in which is installed is known. In this case, the hollow fiber membranes 1 are substantially vertical and are housed in the aerobic tank body 2 in a state where three hollow fiber membranes are arranged side by side with an interval therebetween. As shown in FIG. It is erected and supported between support frames 5 disposed at the ends. The support frame 5 is fixed upright in the aerobic tank 2, and each hollow fiber membrane 1 is fixed in the aerobic tank 2 so as not to move. Although not shown, an air diffusion tube is provided below the hollow fiber membrane 1 in the aerobic tank body 2, and an aerobic state is formed in the aerobic tank body 2 by air ejected from the air diffusion pipe. Is done.

Therefore, in the septic tank, an aerobic state is formed in the aerobic tank body 2 by the air blown out from the diffuser pipe in the aerobic tank body 2, and in the aerobic state, the water to be treated is formed. Activated sludge treatment is performed. That is, the water to be treated is solid-liquid separated in each hollow fiber membrane 1, and in this solid-liquid separation, activated sludge is held in the aerobic tank body 2, while the filtered membrane permeate is treated as treated water. The water to be treated is sent out from the aerobic tank 2 and is aerobically biologically treated by the activated sludge. Further, each hollow fiber membrane 1 is aerated by the air blown from the air diffuser from below, whereby an ascending flow is generated in the water to be treated and adheres to the membrane surface of the filtration membrane of each hollow fiber membrane 1. The cake layer thus removed is peeled off and the film is washed.

[0004]

However, in the above-mentioned prior art, when each hollow fiber membrane 1 is aerated by air blown out from a diffuser, the hollow fiber membrane 1 is stretched by an external force due to air ration. As a result, the hollow fiber membrane 1 is slackened in the middle part thereof, and the pressure loss of the sludge circulating near the middle part increases, and the circulation of the sludge becomes uneven. was there. In addition, there is a problem that the non-uniform circulating flow reduces the flow velocity in the vicinity of the middle part of the hollow fiber membrane 1, lowers the cleaning ability, and leads to blockage of the hollow fiber membrane 1.

[0005] The present invention has been made in order to solve all the problems in the above-mentioned conventional technology, that is, the problem is that the circulating speed is kept uniform without lowering,
An object of the present invention is to provide a septic tank having a high filtration and purification ability, in which the hollow fiber membrane is efficiently washed and its clogging is prevented.

[0006]

According to a first aspect of the present invention, there is provided a septic tank having an aerobic tank in which a hollow fiber membrane is provided, and a tension means for pulling the hollow fiber membrane in a substantially horizontal direction. It is provided. Therefore, in this case, the hollow fiber membrane is pulled in a substantially horizontal direction by the tension means and is always kept in an extended state, so that the hollow fiber membrane is slackened even with respect to the vertical circulation of sludge. Therefore, an increase in pressure loss with respect to the sludge flowing at the same time is prevented, and the circulation speed of the sludge is maintained uniformly without decreasing. As a result, the hollow fiber membrane is efficiently washed without clogging, and the filtration and purification ability is maintained at a high level.

A septic tank according to a second aspect of the present invention is the septic tank according to the first aspect, wherein an air diffuser is provided below the hollow fiber membrane in the aerobic tank. Therefore, in this case, in particular, the hollow fiber membrane is aerated by the air blown out from the air diffuser from below, and ascending flow is generated in the water to be treated, and adheres to the surface of the filtration membrane of the hollow fiber membrane. The cake layer thus removed is effectively peeled off, and more efficient film cleaning is performed.

According to a third aspect of the present invention, there is provided the septic tank according to the second aspect, wherein a plurality of hollow fiber membranes are arranged substantially vertically and are arranged side by side at intervals from each other. It is characterized by having been done. Therefore, in this case, in particular, not only the filtration and washing performance is improved by the plurality of hollow fiber membranes being arranged in parallel, but also the agitated flow smoothly rises between the substantially vertical intervals between the hollow fiber membranes. hand,
The sludge circulation speed is increased and the membrane cleaning ability is also improved.

A septic tank according to a fourth aspect of the present invention is the septic tank according to any one of the first to third aspects, wherein the hollow fiber membrane is supported between the supporting frames provided at both ends thereof. And a tension means for pulling the support frame to the side. Therefore, especially in this case,
Since the hollow fiber membrane is erected and supported between the support frames disposed at both ends thereof, the support frame is pulled to the side by the tension means, so that the entire hollow fiber membrane is substantially uniformly in the substantially horizontal direction. And the slack deformation is reliably prevented.

The septic tank according to a fifth aspect of the present invention is the septic tank according to the fourth aspect, wherein a plurality of hollow fiber membranes are arranged in parallel in the aerobic tank at intervals. In addition, the support frames are mutually connected and integrated between adjacent hollow fiber membranes. Therefore, in this case, in particular, not only the filtration and washing ability is improved by arranging a plurality of hollow fiber membranes side by side, but also the supporting frames at both side ends for supporting and supporting each hollow fiber membrane are mutually adjacent. , The tensile force by the tension means acts uniformly on each hollow fiber membrane via the support frame integrated with the same, and the slack deformation of a plurality of the hollow fiber membranes can be efficiently and reliably performed. Is prevented.

According to a sixth aspect of the present invention, there is provided a septic tank according to any one of the first to fifth aspects, wherein the septic tank is a tension means for pulling by a spring. Therefore, in this case, in particular, the hollow fiber membrane is elastically pulled and held by the spring, so that the shock applied to the hollow fiber membrane when the sludge is circulated is absorbed and its breakage is prevented.

A septic tank according to a seventh aspect of the present invention is the septic tank according to any one of the first to fifth aspects, characterized in that the septic tank is tension means for pulling by a weight. Therefore, in this case, in particular, since the tensile force of the weight body does not change, the hollow fiber membrane is secured in a stretched state with a constant tensile force.

[0013]

1 to 3 show the first embodiment of the present invention.
6 shows an embodiment corresponding to FIG. 6, a septic tank having an aerobic tank body 2 in which a hollow fiber membrane 1 is provided, and a tension means 3 for pulling the hollow fiber membrane 1 in a substantially horizontal direction. Is provided. In the septic tank of this embodiment, an air diffuser 4 is provided below the hollow fiber membrane 1 in the aerobic tank body 2, and the hollow fiber membranes 1 are substantially vertical and a plurality of hollow fiber membranes 1 are arranged at intervals from one another. It is installed in the aerobic tank body 2 in the installed state. The hollow fiber membrane 1 is supported by being supported between support frames 5 provided on both side ends thereof, and serves as tension means 3 for pulling the support frame 5 to the side. In this case, the supporting frames 5 are mutually connected and integrated between the adjacent hollow fiber membranes 1, and the tension means 3 is pulled by the spring 6.

As the hollow fiber membrane 1, various materials can be used. For example, those made of various materials such as cellulose, polyolefin, polyvinyl alcohol, PMMA, and polysulfone can be used. .
However, considering the ease of processing into a knitted fabric, it is preferable to use a material having a high elongation such as polyethylene. In addition, if it can be used as a filtration membrane,
The pore diameter, porosity, film thickness, outer diameter, etc. are not particularly limited.

The hollow fiber membrane 1 has a horizontally long rectangular shape, and has support frames 5 fixedly attached to both ends thereof, and is supported by the support frames 5 on both sides so as to be substantially vertical. The support frame 5 is made of a high-strength material such as a metal or a synthetic resin. Further, three hollow fiber membranes 1 are arranged side by side with an interval therebetween, and the number of the arranged side panels, the dimension of the interval, and the like are appropriately set according to the filtration capacity. The support frames 5 adjacent to each other between the hollow fiber membranes 1 are integrally connected to each other by an appropriate connecting means such as an adhesive or a fixing tool.

Of the three support frames 5 integrated and integrated,
Guide rollers 7 are disposed and fixed to the outer surfaces of the outermost support frames 5 located on both sides. In this case, two sets of the guide rollers 7 are arranged facing each other in the upper and lower directions to form a set, and the set of the guide rollers 7 is formed on the upper portion of the outer surface of one support frame 5.
There are three sets in the middle and lower part. Similarly, the guide rollers 7 are disposed and fixed also on the support frames 5 on both side ends of the hollow fiber membrane 1, so that three sets of the guide rollers 7 are disposed and fixed on the support frames 5 located at the four corners. Will be.

On the opposed inner wall surfaces of the aerobic tank 2,
On both sides, support rails 8 are provided at upper, middle and lower portions in a rod-like manner. In this case, each support rail 8 is disposed at a position corresponding to each set of the guide rollers 7, and the upper and lower guide rollers 7 of each set roll on the support rail 8, as shown in detail in FIG. By being freely engaged, the three hollow fiber membranes 1 integrated via the support frame 5 are collectively supported substantially vertically. Further, on both sides of the hollow fiber membrane 1, a support frame 5 integrated and integrated is supported so as to be slidable in a substantially horizontal direction.

Between the vertically central portion of the integrated support frame 5 and the inner wall surface of the aerobic tank 2, springs 6 connecting the two are interposed in the horizontal direction for each of the three support frames 5. The three springs 6 serve as tensioning means 3 for pulling the three hollow fiber membranes 1 in a substantially horizontal direction. In this case, tension means 3 by the same spring 6 are similarly arranged on both sides of the hollow fiber membrane 1, and each hollow fiber membrane 1 is equally pulled to both sides. or,
The initial value of the tension force by each spring 6 is 4 kg, and the tension means 3 on one side is 12 kg in total, and the tension means 3 is pulled from both sides by the tension force of 12 kg.
Note that the pulling force is appropriately changed and set according to the material of the hollow fiber membrane 1, the number of juxtaposed fibers, and the like.

On both outer sides of the hollow fiber membranes 1 arranged side by side,
A circulation partition 2a is disposed and fixed substantially parallel to the hollow fiber membrane 1, and the aerobic tank body 2 is provided inside the circulation divider 2a on both sides.
An air diffuser 4 is provided at a lower part of the inside. In this case, an upward stirring flow is generated in the space between the circulating partition plates 2a on both sides by the air blown from the diffuser pipe 4 from below, and a downward flow is generated in the space on both outer sides of the circulating partition plate 2a. As a result, circulating water to be treated containing sludge is formed in the aerobic tank 2.

Therefore, in the septic tank according to this embodiment, the aerobic state is formed in the aerobic tank body 2 by the air blown out from the diffuser pipe 4 in the aerobic tank body 2. Activated sludge treatment of the water to be treated is performed. That is, the water to be treated is solid-liquid separated in each hollow fiber membrane 1, and in this solid-liquid separation, activated sludge is held in the aerobic tank body 2, while the filtered membrane permeate is treated as treated water. Aerobic tank 2
And the treated water is aerobically biologically treated by the activated sludge. Further, each hollow fiber membrane 1 is aerated by the air blown from the air diffuser 4 from below, whereby a rising agitated flow is generated in the water to be treated, and the surface of the filtration membrane of each hollow fiber membrane 1 is formed. The attached cake layer is peeled off, and the film is washed.

The treated water sent out from the aerobic tank 2 is
As shown in FIG. 3, the treated water is sent to a storage tank body 10 for storing treated water through a communication pipe 9, then pumped up from the storage tank body 10 by a discharge pump 11, and then disinfected by a discharge pipe 12.
It is sent to 13, after which it is discharged outside the septic tank.
Further, in the septic tank, two flow control tank bodies 14 are disposed on the drain inflow side, and after adjusting the inflow amount of the wastewater flowing into the two flow control tank bodies 14, the sludge is transferred by the transfer pump 15. The air is transferred to the aerobic tank 2 through the transfer pipe 16. Then, the two flow control tanks 14 and the aerobic tank 2
The water level is detected by a water level detection unit 17 provided in each of them, and a control unit 18 that controls the operations of the transfer pump 15 and the discharge pump 11 according to the detected water level is provided. In this case, the water levels L1, L to be detected in the flow rate adjusting tank 14 and the aerobic tank 2
2 is set in advance.

Therefore, in the septic tank of this embodiment, since the hollow fiber membrane 1 is pulled in the substantially horizontal direction by the tension means 3 and is always kept in an expanded state, the hollow fiber membrane 1 is also protected against the vertical flow of sludge. The hollow fiber membrane 1 is not slackened, the pressure loss of the sludge flowing at the same time is prevented from increasing, and the circulation speed of the sludge is kept uniform without decreasing. As a result, the hollow fiber membrane 1 is efficiently washed without clogging, and the filtration and purification ability is maintained at a high level. That is, as shown in FIG. 1A, in the middle part of the aerobic tank body 2 (the part surrounded by the two-dot chain line), the hollow fiber membrane 1 does not loosen, and the pressure loss to the circulating sludge is reduced. The sludge does not increase, and a decrease in the circulation speed of the sludge is prevented.

Further, in the septic tank of this embodiment, the hollow fiber membrane 1 is blown by air blown from the air diffuser 4 from below.
Is aerated, a rising stirring flow is generated in the water to be treated, and the cake layer attached to the membrane surface of the filtration membrane of the hollow fiber membrane 1 is effectively peeled off, and more efficient membrane washing is performed. In addition, in this case, since the hollow fiber membranes 1 are substantially vertical and a plurality of hollow fiber membranes are arranged side by side with an interval therebetween, not only the filtration and washing performance is improved, but also the hollow fiber Membrane 1
The agitated flow smoothly rises in the interval between the sludges, thereby increasing the circulation speed of the sludge and improving the membrane cleaning ability.

In the septic tank of this embodiment, since the hollow fiber membrane 1 is supported between the supporting frames 5 disposed on both side ends thereof, the supporting frame 5 is laterally moved by the tension means 3. By being pulled, the entire hollow fiber membrane 1 is evenly pulled substantially in the horizontal direction, and the loosening deformation is reliably prevented. Moreover, in this case, a plurality of hollow fiber membranes 1 are juxtaposed at a distance from each other, and support frames 5 on both side ends for supporting and supporting each hollow fiber membrane 1 are connected and integrated with each other. Therefore, the tensile force of the tension means 3 uniformly acts on each hollow fiber membrane 1 via the support frame 5 integrated and integrated, and the slack deformation of the plurality of hollow fiber membranes 1 is efficiently and reliably prevented. Is done. Further, since the tension means 3 is pulled by a spring, the hollow fiber membrane 1 is elastically pulled and held, and the shock applied to the hollow fiber membrane 1 at the time of sludge circulation is absorbed to prevent breakage.

FIGS. 4 and 5 show another embodiment corresponding to claims 1 to 5 and 7 of the present invention. In the septic tank of this embodiment, the tension means 3 is pulled by a weight 19. In this case, as shown in detail in FIG. 5, the middle of the cord 20 that suspends and supports the weight 19 is wound around the support roller 21, and the tip of the cord 20 is substantially at the center of the support frame 5. The supporting roller 21 is rotatably attached to a tip end of a supporting rod 22 protruding from an inner wall surface of the aerobic tank 2. Further, the tension means 3 including the same weight 19, the cord-like body 20, the support roller 21 and the like are similarly arranged on both sides of the hollow fiber membrane 1, and each hollow fiber membrane 1 is equally pulled to both sides. .

Therefore, in the septic tank of this embodiment, in particular, since the pulling force of the weight 19 does not change,
Each hollow fiber membrane 1 is secured in a stretched state with a constant tensile force. The other configuration is the same as that of the above embodiment, and the same operation and effect as those of the above embodiment can be obtained.

FIG. 6 shows still another embodiment corresponding to claims 1 to 5 and 7 of the present invention. In the septic tank of this embodiment, a weight 19, a cord 20 and a support roller 21 are used. Is provided on only one side of the hollow fiber membrane 1. The other configuration is the same as that of the above embodiment, and the same operation and effect as those of the above embodiment can be obtained.

[0028]

As described above, in the septic tank according to the first aspect of the present invention, the hollow fiber membrane is held in a stretched state by being pulled in a substantially horizontal direction. No increase in pressure loss to the circulating sludge is prevented, and the circulating speed of the sludge is maintained uniformly without lowering, whereby the hollow fiber membrane is efficiently washed and clogged without filtration. Purification capacity is kept high.

Further, in the septic tank according to the second aspect of the present invention, the hollow fiber membrane is aerated by air from below which is blown out from the air diffuser, and an ascending flow is generated in the water to be treated. The cake layer adhering to the membrane surface of the filtration membrane of the hollow fiber membrane is effectively peeled off, and more efficient membrane cleaning is performed.

In the septic tank according to the third aspect of the present invention, in particular, not only the hollow fiber membranes are arranged in parallel to improve the filtration / cleaning ability but also each of the hollow fibers which are substantially vertical. The agitated flow smoothly rises between the membranes, thereby increasing the sludge circulation speed and improving the membrane cleaning ability.

Further, in the septic tank according to the fourth aspect of the present invention, since the hollow fiber membrane is particularly supported between the supporting frames provided at both ends thereof, the supporting frame is supported by the tension means. By being pulled in the direction, the hollow fiber membrane is pulled evenly in the substantially horizontal direction as a whole, so that the slack deformation is reliably prevented.

In the septic tank according to the fifth aspect of the present invention, in particular, the filtration and washing ability is improved by providing a plurality of hollow fiber membranes in parallel, and the hollow fiber membranes between adjacent hollow fiber membranes can be improved. Since the support frames are combined and integrated with each other, the tensile force by the tension means acts evenly on each hollow fiber membrane through the support frame integrated and integrated with the same, and the slack deformation of a plurality of the hollow fiber membranes is prevented. It is prevented efficiently and reliably.

In the septic tank according to claim 6 of the present invention, the hollow fiber membrane is particularly elastically pulled and held by the spring, so that the shock applied to the hollow fiber membrane during the circulation of sludge is absorbed. Damage is prevented.

In the septic tank according to claim 7 of the present invention, in particular, since the pulling force of the weight does not change,
The hollow fiber membrane is secured in a stretched state with a certain tensile force.

[Brief description of the drawings]

1A and 1B show an internal structure of an aerobic tank in a septic tank according to an embodiment of the present invention, wherein FIG. 1A is a plan view and FIG.

FIGS. 2A and 2B show an essential part structure in the aerobic tank body, wherein FIG. 2A is an enlarged side view thereof, and FIG.

FIG. 3 is a schematic side view showing the internal structure of the entire septic tank.

4A and 4B show an internal structure of an aerobic tank body in a septic tank according to another embodiment of the present invention, wherein FIG. 4A is a plan view and FIG.

FIGS. 5A and 5B show an essential part structure in the aerobic tank body, FIG. 5A is an enlarged side view thereof, and FIG. 5B is an enlarged front view thereof.

FIG. 6 is a front view showing the internal structure of an aerobic tank in a septic tank according to still another embodiment of the present invention.

FIG. 7 is a schematic plan view showing an internal structure of an aerobic tank in a conventional septic tank.

8A and 8B show a hollow fiber membrane in a septic tank according to the conventional example, wherein FIG. 8A is a plan view and FIG. 8B is a front view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hollow fiber membrane 2 Aerobic tank 3 Tension means 4 Air diffuser 5 Support frame 6 Spring 19 Weight

Claims (7)

[Claims] 1. A septic tank having an aerobic tank body in which a hollow fiber membrane is provided, wherein the septic tank includes tension means for pulling the hollow fiber membrane in a substantially horizontal direction. 2. The septic tank according to claim 1, wherein an air diffuser is disposed below the hollow fiber membrane in the aerobic tank. 3. The septic tank according to claim 2, wherein the hollow fiber membranes are substantially vertical and are installed in the aerobic tank body in a state where a plurality of hollow fiber membranes are juxtaposed at intervals. 4. A tensioning means for supporting a hollow fiber membrane between supporting frames provided on both side ends thereof and pulling the supporting frame to the side. A septic tank according to any one of the preceding claims. 5. A plurality of hollow fiber membranes are installed in an aerobic tank with a plurality of hollow fiber membranes arranged side by side at an interval from each other, and a supporting frame is mutually connected and integrated between adjacent hollow fiber membranes. The septic tank according to claim 4, characterized in that: 6. A septic tank according to claim 1, wherein said septic tank is tension means for pulling by a spring. 7. The septic tank according to any one of claims 1 to 5, wherein the septic tank is tension means for pulling by a weight.