JP2001276863A - Moving bed drain treatment equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a moving bed drain treatment equipment capable of sufficiently removing BOD, etc., by preventing generation of any shortcut stream and also inhibiting the clogging of a membrane module for solid-liquid separation. SOLUTION: A membrane module 14 is placed inside the treatment vessel 11 into which a fluid carrier 22 is changed, and a fluidization means such as air diffuser for generating a circulation stream on the periphery of the membrane module 14 is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving bed type wastewater treatment apparatus, and more particularly to a moving bed type wastewater treatment apparatus capable of simultaneously removing BOD and the like and solid-liquid separation.

[0002]

2. Description of the Related Art An immersion type membrane filtration device, which has been rapidly commercialized in recent years as a solid-liquid separation means in various water treatments, comprises a flat membrane or a hollow fiber membrane in a treatment tank. Since treatment can be performed by immersing the membrane module, there is an advantage that solid-liquid separation can be reliably performed with a simple and compact device configuration. Further, a wastewater treatment apparatus that combines solid-liquid separation with such a membrane module and wastewater treatment such as an activated sludge method is being developed.

However, if the membrane module is simply immersed in a treatment tank such as an activated sludge method, a short-circuit flow occurs in which raw water flowing from a raw water inflow portion is sucked into the membrane module without being treated. In some cases, BOD or the like was not sufficiently removed. In order to avoid this, it is conceivable to install the raw water inflow section and the membrane module at a sufficient distance, but this is not preferable because the processing tank becomes large. In addition, if the water around the membrane module is not sufficiently agitated, clogging of the membrane will occur in a short time due to sludge and carriers floating in the water, so that the membrane must be washed frequently.

Accordingly, the present invention provides a moving bed type wastewater treatment apparatus capable of sufficiently preventing BOD and the like by preventing generation of a short circuit flow and suppressing clogging of a membrane module for performing solid-liquid separation. It is intended to be.

[0005]

In order to achieve the above object, a moving bed type wastewater treatment apparatus of the present invention immerses a membrane module in a treatment tank charged with a fluid carrier and circulates the membrane module around the membrane module. A flow generating means for generating a flow is provided, and a screen for separating the flow carrier is provided around the membrane module. Further, the flow generating means is an air diffuser, the flow carrier is a biofilm carrier, and further, a jet agitation solid-liquid separation device is provided in a preceding stage of the processing tank. I have.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a sectional front view showing one embodiment of a moving bed type wastewater treatment apparatus of the present invention, FIG. 2 is a sectional side view, FIG. 3 is a plan view, and FIG. It is a perspective view which shows the example of a shape.

The moving floor type wastewater treatment apparatus 10 includes a treatment tank 11, a membrane module 12 immersed in water in the treatment tank 11, and a screen provided so as to cover the entire circumference of the membrane module 12. 13, a diffuser 14 as a flow generating means provided on one side of the bottom of the processing tank 11, a raw water inflow pipe 15 provided on the upper part of the processing tank 11, and provided on the bottom of the processing tank 11. A cleaning drainage pipe 16, a membrane cleaning air diffuser 17 provided in the screen 13 below the membrane module 12, and an overflow pipe 18 above the processing tank.
And

The movable floor type wastewater treatment apparatus 10 formed as described above is used in a state where water is filled so that water passage portions 19a and 19b having a sufficient flow area are formed above and below the membrane module 12. A fluid carrier 20 having a predetermined size and shape is charged into the water. Various fluid carriers can be used as the fluid carrier 20, but a plastic carrier obtained by adding an inorganic substance such as silica or calcium for adjusting the specific gravity or a metal powder to a plastic such as polypropylene or polyethylene may be used. preferable.

[0009] The plastic carrier is capable of adjusting the specific gravity arbitrarily by adjusting the amount of silica or the like added, and can be formed into an appropriate shape such as a sphere or a pipe. Has advantages. For example,
As shown in FIG. 4, a carrier provided with a plurality of partition plates 23 inside a cylindrical body 22 having radial fins 21 on the outer periphery is:
Even if the carriers collide with each other, the microorganisms adhering to the inside of the cylinder will not be separated, and the required amount of microorganisms can be surely adhered and inhabited. Has the advantage of being obtained,
The fluid carrier 20 is optimal. Further, those having fine irregularities on the surface are more susceptible to biofilm adhesion,
It is preferable to provide a hole having a diameter of about 00 μm since an optimum habitat for microorganisms can be formed.

The size of the fluid carrier 20 is suitably about 3 to 20 mm. For example, in the shape shown in FIG.
The diameter of the cylindrical body 22 is 10 to 15 mm and the length is 7 to 15 m
m is optimal. If the size of the fluid carrier 20 is small, a fine screen must be used as the screen 13, which increases the cost of the screen itself and increases the possibility of clogging. Conversely, if it is too large, the effective area to which the microorganisms adhere will decrease.

The specific gravity of the fluid carrier 20 is set to 0.9 to 0.9 so that the fluid can be fluidized at the same speed as the water circulating in the tank.
A range of 1.2 is appropriate. If the specific gravity of the fluid carrier 20 is too small, most of the fluid will float near the water surface, and the function as the biofilm-attached carrier will not be sufficiently exhibited. Similarly, if the specific gravity is too large, the fluid carrier 20 will settle to the bottom of the treatment tank, and in any case, the flow rate of the circulating flow for fluidizing the fluid carrier 20 must be increased, so The cost required for fluidization increases.

The screen 13 allows water to pass therethrough without passing through the fluid carrier 20, and separates the two. The screen 13 may be a net (net). By using a wire in which parallel wires or the like are arranged at predetermined intervals on the outer surface, the fluid carrier 20 is hardly caught by the screen 13 and clogging of the screen 13 can be prevented.

By providing such a screen 13 around the membrane module 12, it is possible to prevent the fluid carrier 20 from being captured and adhered to the membrane module 12, thereby causing clogging of the membrane. Further, by providing the V-shaped or U-shaped current plate 24 so as to cover the lower portion of the screen 13, the flow carrier 20 can be prevented from being caught on the lower end of the screen 13, and the circulating flow in the tank can be prevented. Movement can be smooth. The screen 13 can be omitted when the fluid carrier 20 captured by the membrane module 12 can be treated under conditions that allow it to be separated by flowing water or the fluid carrier 20.

The membrane module 12 can use a hollow fiber membrane or the like used in an ordinary membrane separation device, and can use an MF membrane, a UF membrane, or a mesh body of an appropriate mesh. it can.

The moving bed type wastewater treatment apparatus 10 thus formed is connected to a treated water outflow pipe 12a through a membrane module 12.
Raw water into the raw water inflow pipe 1
5 and into the processing tank 11,
The operation is performed in a state where compressed air is supplied to the a and air is diffused from the air diffuser 14 at a predetermined intensity. The raw water flowing into the treatment tank 11 is mixed with the downward flow circulating around the membrane module 12, flows down while contacting the fluid carrier 20, and flows into the air diffuser 14 through the lower water passage 19b. . further,
The bubbles diffused from the diffuser 14 form an ascending flow, rise together with the fluid carrier 20 while being agitated, flow down through the upper water passage 19a, and thus circulate around the membrane module 12. .

BOD and the like in the raw water are sequentially treated by microorganisms attached to the fluid carrier 20 in the circulating flow, and after a part of the circulating flow is separated from the fluid carrier 20 through the screen 13, the membrane module The water is sucked into and discharged from the treated water outflow pipe 12a.

As described above, by forming a circulating flow around the membrane module 12 and performing water treatment, the raw water inflow pipe 1 is formed.
5 can be prevented from being short-circuited and drawn into the membrane module 12 without being treated. Further, by bringing the water and the fluid carrier 20 into contact with each other in the circulating flow, the contact between the water and the fluid carrier 20 can be made uniform, thereby improving the processing efficiency. Further, since water is circulated around the membrane module 12, the size of the processing tank 11 can be reduced. Further, since water is constantly flowing on the surface of the membrane module 12, clogging of the membrane can be suppressed and the load on the membrane can be reduced. When the residence time in the moving bed type wastewater treatment apparatus 10 is to be lengthened, the treatment water may be intermittently taken out from the membrane module 12 instead of increasing the volume of the treatment tank 11. While taking out the treated water from the module 12, the inflow of the raw water may be stopped.

In particular, by installing a screen 13 for separating the fluid carrier 20 around the membrane module 12,
The fluid carrier 20 can be reliably prevented from adhering to the membrane surface. Furthermore, more effective water treatment can be performed by performing a fluidized bed biofilm treatment using a biofilm carrier as the fluid carrier 20. Further, the formation of the circulation flow can be easily performed only by providing the air diffuser 14 on one side of the membrane module 12. When the treatment is performed in an anaerobic or oxygen-free atmosphere, a stirrer or a pump may be provided at an appropriate position as a flow generating means to provide a flow without providing a diffuser.

The cleaning of the membrane module 12 can be appropriately performed by introducing backwash water from the treated water outflow pipe 12a or by diffusing air from the membrane cleaning diffuser 17 by supplying compressed air from the diffuser pipe 17a. It can be performed in combination. The washing wastewater at this time may be discharged from the washing wastewater discharge pipe 16 and first returned to the sedimentation basin or the like.

FIG. 5 is a schematic system diagram showing an example of a wastewater treatment facility using the moving floor wastewater treatment apparatus of the present invention. This wastewater treatment equipment is provided with a jet-stirred solid-liquid separator 30 for separating solid components in raw water at the preceding stage of the moving bed type wastewater treatment device 10 as shown in the above embodiment. This jet agitation solid-liquid separation device 30 has a plurality of perforated plates 31 inserted perpendicular to the flow direction of raw water, and raw water mixed with a flocculant in a flocculant addition mixing tank 32 is
Spouts are ejected downstream from a plurality of ejection holes 33 provided at predetermined positions of the perforated plate 31 to form flocs having a high sedimentation property by a stirring action by the energy of the ejected water. The formed floc is settled at the perforated plate 31 and the inclined pipe 34 according to the sedimentation property, and is discharged from the mud discharge pipe 35 at the bottom. The jet agitation solid-liquid separation device 30 has an excellent solid-liquid separation ability because it obtains a stirring action by the energy of water without requiring a stirrer or the like.
There is an advantage that equipment costs and operation costs are low.

The load on the membrane module 12 can be further reduced by treating the raw water that has been subjected to solid-liquid separation by such a jet-stirring solid-liquid separator 30 with the moving-bed type wastewater treatment apparatus 10. In addition, a stable water treatment operation can be continuously performed for a long time, and the cleaning interval of the membrane module 12 can be extended.

[0022]

As described above, according to the moving bed type wastewater treatment apparatus of the present invention, the formation of the circulating flow around the membrane module can prevent the occurrence of the short circuit flow and can prevent the membrane from being clogged. And the load on the film can be reduced. Furthermore, since the fluidized carrier and the raw water can be brought into uniform contact, the processing efficiency such as BOD removal can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional front view showing one embodiment of a moving-floor-type wastewater treatment apparatus of the present invention.

FIG. 2 is a sectional side view of the same.

FIG. 3 is a plan view of the same.

FIG. 4 is a perspective view showing a shape example of a fluid carrier.

FIG. 5 is a schematic system diagram showing an example of a wastewater treatment facility using the moving floor wastewater treatment apparatus of the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Moving floor type wastewater treatment apparatus, 11 ... Treatment tank, 12 ... Membrane module, 12a ... Treated water outflow pipe, 13 ... Screen, 14 ... Aeration device, 15 ... Raw water inflow pipe, 16 ... Cleaning drainage discharge pipe, 17 ... diffuser for membrane cleaning, 18 ... overflow pipe, 19a, 19b ... water passage, 20 ... fluid carrier, 21
... Fin, 22 ... Cylinder, 23 ... Partition plate, 24 ... Rectifier plate, 30 ... Jet-stirring solid-liquid separator, 31 ... Perforated plate, 32
… Coagulant addition and mixing tank, 33… through hole, 34… inclined tube, 35
… Sludge pipe

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B01D 65/08 500 C02F 1/44 F C02F 1/44 C B01D 23/02 A (72) Inventor Minami Ozawa 3 1-3 Kyobashi, Chuo-ku, Tokyo F-term (reference) in Maezawa Kogyo Co., Ltd. 4D003 AA14 AA15 AA16 AB02 AB04 BA02 CA02 CA10 DA04 DA07 DA30 EA04 EA14 EA26 EA28 4D006 GA06 GA07 HA03 HA93 JA31A JA70A KA01 KA02 KA03 KA44 KB13 KB22 KC03 KC14 KD08 PC64 PC80 4D041 AB07 AC01

Claims (5)

[Claims] 1. A moving bed type wastewater treatment apparatus characterized in that a membrane module is immersed in a treatment tank charged with a fluid carrier, and a flow generating means for generating a circulating flow around the membrane module is provided. 2. The moving bed type wastewater treatment apparatus according to claim 1, wherein a screen for separating the fluid carrier is provided around the membrane module. 3. The moving-floor wastewater treatment apparatus according to claim 1, wherein said flow generating means is an air diffuser. 4. The moving bed type wastewater treatment apparatus according to claim 1, wherein the fluid carrier is a biofilm carrier. 5. The moving-bed type wastewater treatment apparatus according to claim 1, wherein a jet-stirring solid-liquid separation device is provided in a stage preceding the treatment tank.