JPH0788305A - Upward current filter device - Google Patents

Abstract

PURPOSE:To increase a capacity to capture SS and to enable washing without using filtrate by forming packed layers packed with filter media of the particles smaller nearer the filter chambers of upper stages in a floating state and space parts below these layers in the plural filter chambers and providing the space parts with air diffusing means. CONSTITUTION:The filter media (a) of porous granular materials having a water floating property and coarse grain sizes are packed into the filter chamber D to form the packed layer A. The granular filter media (b) of porous granular materials having the grain sizes smaller than the grain sizes of the filter media a and having the water floating property as well are packed into the filter chamber E above the filter chamber described above to form the packed layer B. The air diffusing member 2 is installed in the lower part of the packed layer A of the filter chamber D and air is supplied from a gas supplying pipe 13 thereto to diffuse the air into the packed layer. The air diffusing member 15 is similarly installed to the lower part of the packed layer B of the filter chamber E and the air is supplied from a gas supply pipe 16 thereto to diffuse the air into the packed layer B. A raw water supplying pipe 5 is installed to a settling section c of the lowermost layer. The bottom thereof is provided with a sludge outflow pipe 8 for discharging settled sludge 7 composed of the easily settleable SS.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a filtration device.

[0002]

2. Description of the Related Art Conventionally, sand, which is heavier than water, has been used as a filter medium.
As a downflow filtration method using anthracite, a two-layer filtration method is known in which a sand layer having a smaller particle size and a larger specific gravity is provided below an anthracite layer having a larger particle size and a smaller specific gravity. On the other hand, an upflow filtration device using a filter material that floats on water is known in JP-A-51-118161, and there are examples. However, since the conventional technique is a single-layer filtration method using one type of floating filter material, the amount of trapped SS is small and clogging occurs, so frequent filter layer cleaning is required. Particularly, in the upward flow filtration using the floating filter medium, there is no conventional concept that the filter layer has two layers.
No concrete means for that purpose is disclosed.

[0003]

DISCLOSURE OF THE INVENTION The present invention provides an upflow filtration device of a new type which has a large SS trapping capacity, a high SS removal rate, and can be washed without using filtered water. It is an issue.

[0004]

The above object can be achieved by the upflow filtration apparatus of the present invention described below. That is, 1) a plurality of filtration chambers are formed by partitioning the inside of the tank with porous water-permeable members to form a plurality of filtration chambers, and a portion below the lowermost porous water-permeable member is a settling section, and raw water is supplied to the settling section. , A means for discharging precipitates is provided at the bottom of the tank, and a plurality of filtration chambers formed between the porous water-permeable members above the lowermost porous water-permeable member are buoyant to water, respectively, The packed bed is filled with a filter medium of small particles in a floating state in the filtration chamber, and a space is formed below the packed bed, and an aeration means is provided in the space, and treated water is disposed above the uppermost porous water-passing member. An upflow filtration device, preferably 2) the particle size of the filter medium filled in the lowermost packed layer of the filter medium is 5 mm.
Above 60 mm, the particle size of the filter medium packed in the uppermost packed layer is 0.5 mm or more and less than 5 mm, and the particle size of the filter medium packed in the upper packed layer of the adjoining filtration chambers is the lower packed layer. This is achieved by the upflow filtration device according to 1) above, which does not exceed the particle size of the filter medium packed in the layer.

The upflow filtration apparatus of the present invention is shown in FIG.
A configuration example of the present invention will be described below with reference to FIG.
After that, the operation will be described, but the following configuration example and description of the operation do not limit the present invention.

In FIG. 1, the upflow filtration device 1 is composed of three porous water-permeable members, that is, porous water-permeable members 2, 3 and 4 extending downward from the inside of the device 1. It is divided into four layers of filtration chambers. The fractionated four-layer filtration chamber has a sedimentation portion C from the lowermost layer, a filtration chamber D through the porous water-passing member 2, a filtration chamber E through the porous water-passing member 3, and an uppermost layer. A space F is formed through the porous water-permeable member 4. The lowermost settling portion C and the uppermost space portion F are not filled with the filter medium. The filtration chamber D is filled with a filter material a of a porous particle having a water-floatability and a coarse particle size to form a packed bed A, and the filtration chamber E above it has a particle size smaller than that of the filter material a and is still water-floatable. A granular filter medium b is filled with the porous granular material to form a packed bed B. The thickness of the packing layer A is about 0.5 to 2 m, and the packing layer B is
The layer thickness is preferably about 0.5 to 2 m, but the thickness of both layers may be the same or different. Further, the thickness of the filtration chamber D and the filtration chamber E is also about 0.5 to 2 m, but these filtration chambers are not particularly limited as long as the filtration media a and b are sufficiently expanded and disturbed during cleaning.

A raw water supply pipe 5 equipped with a raw water supply valve 6 is installed in the lowermost settling section C to supply raw water from outside the system.
A valve 18 is provided at the bottom of the settling section C, and a settling discharge pipe 8 for discharging the settling sludge 7 composed of SS that easily settles is provided. The raw water supply pipe 6 may be connected to a coagulant addition pipe 10 provided with an addition valve 11 near the opening to the apparatus 1. Settling part C through the porous water-passing member 2
In the filtration chamber D provided in the upper part of the above, the filter medium a is not fully filled in the filtration chamber D, and therefore, when filtering raw water, the filter medium a is filled below the porous water-passing member 3. The packed bed A is formed in this state, and the diffusion member 12 is installed below the packed bed A in the filtration chamber D. An oxygen-containing gas such as air is supplied to the diffuser member 12 from the outside of the system through a gas supply pipe 13 equipped with a valve 14, and diffuses into the packed bed A.

Similarly, in the filtration chamber E provided above the filtration chamber D via the porous water-passing member 3, the filter medium b is filtered in the filtration chamber E.
Therefore, when the raw water is not completely filled, and thus the raw water is being filtered, the filter medium b is filled under the porous water-permeable member 4 to form the packed bed B. An air diffuser 15 is installed in the lower part of B. The aeration member 15 includes
Air is supplied to the diffuser member 15 from the air supply pipe 16 provided with the valve 17 to diffuse the air into the packed bed B. Further, in the filtration chamber E, an intermediate drain pipe 18 equipped with a valve 19 which is sometimes used for cleaning drainage is installed. The upper part of the packed bed B is a space F through the porous water-passing member 4, and the outer wall of the device 1 forming the space F serves as the overflow weir 17, and is provided around the overflow weir 17. The filtered water flows out of the system through a filtered water outflow pipe 22 provided with a valve 23 provided in the filtered water conduit 21. The above is the device 1
2 is an example of the configuration of FIG.

The material of the filter medium composed of the water-floating porous granular material filled in the packed bed A and the packed bed B may be the same or different. However, the filter medium is water floatable, and the particle size d _{1 of the} filter medium a filled in the packed bed A is
It is important that is larger than the particle size d ₂ of the filter medium b packed in the packed bed B. As a preferable particle diameter, the particle diameter d ₁ of the filter medium a is 5 to 60 mm, and the particle diameter d ₂ of the filter medium b is 0.5 to 5 mm. As the constituent material of the filter medium,
It is not particularly limited as long as it is a water-floating porous granular material, but examples of preferable constituent materials include foamable plastics such as polyurethane foam, expanded polystyrene, expanded polyethylene, expanded polypropylene, and lightweight mineral aggregates. Is. In particular, as the filter material of the filling layer A, a material capable of capturing SS in the structure of the filter material itself is preferable, and for example, a material such as polyurethane foam having a three-dimensional network structure is preferable.

[0010]

The function of the present invention will be described below. For example, raw water containing SS such as sewage and sewage activated sludge treated water flows from the raw water supply pipe 5 into the settling section C at the lower part of the filtration device 1 of the present invention, and the settling section C has good settling properties such as coarse particles. After the matter is precipitated, it becomes an upward flow and flows into the packed bed A filled with the water-floating porous granular material filter medium a, and most of SS is filtered and removed here. Then, the outflow water from the packed bed A flows into the packed bed B filled with the filter material b of the water-floating porous granular material having a smaller particle size, and the residual SS not removed by the packed bed A is highly advanced. And the clear filtered water flows out from the filtered water outflow pipe 22. When performing coagulation filtration, a coagulant such as PAC or a cationic polymer is added to the raw water through the coagulant addition pipe 10 in the raw water supply pipe 5 to coagulate and settle SS that aggregates in the settling section C.

In addition, in the filtration device 1 of the present invention, it is also possible to attach microorganisms to the filter medium to carry out biological filtration. When performing aerobic biological filtration, at least air is diffused from the aeration member 12 For example, an oxygen-containing gas may be supplied to the packed bed A. Furthermore, air is supplied from the air supply pipe 16 to the diffuser member 15 provided in the lower portion of the packed bed B to maintain the packed bed B aerobic, while the diffuser of the oxygen-containing gas from the diffuser member 12 is performed. It is also possible to stop and perform biological treatment by keeping the packed bed A anaerobic.

The present invention is characterized in that a filter material made of a water-floating porous granular material is used as the filter material to be filled in the packed bed A and the packed bed B. By using a water-floating filter medium, the filter bed, that is, the packed bed, has a porous water-permeable member having eyes that do not allow the filter medium to pass through and is stretched across the appropriate place inside the device, and the lower part is filled with the filter medium. It can be easily installed. Since the raw water to be filtered is supplied to the packed bed of the filter bed as an upward flow from the lower part of the packed bed, the SS solid-liquid separated in the lower part of the packed bed may aggregate with each other and naturally settle. Yes, and can be easily washed by the method for washing the packed bed described below. Furthermore, during cleaning, when air is supplied from the air diffuser and air is agitated, the particles of the filter medium also move violently along with the vigorous movement of water, and the SS trapped in the filter medium is discharged out of the system along with the drain water. can do.

Conventionally, in the treatment step in which raw water is passed through an upward flow to a filtration device having a packed bed in two stages like the device 1 of the present invention and filtered, a water-floating porous granular material is provided in the upper stage. An example of using a filter medium of the present invention is pending in 1993 Japanese Patent Application No. 90489, but filtration of raw water containing a large amount of SS such as sewage is also used in the lower stage by using a filter material of a water-floating porous granular material. Could not be used for. In the present invention, the filter material is used in the lower stage due to the development of a water-floating porous granular filter material having a larger particle size, and the SS is improved by using the water-floating porous granular filter material in both upper and lower stages. It is possible to obtain treated water that has been removed to
Moreover, the increase in filtration resistance is extremely small, and the increase in SS in the treated water allows the raw water to pass through to the limit of filtration.

When the amount of SS in the treated water increases and the quality of the treated water deteriorates, the packed bed A and the packed bed B are washed by the following method. This cleaning method is also unique to the present invention and is characterized in that there is no need to perform backwashing with treated water. That is, the raw water supply valve 6 is closed, the supply of raw water from the raw water supply pipe 5 is stopped, and the aeration members 12 and 15
When air is vigorously blown into the apparatus 1 from above, the filter media a and the filter media b in the packed bed A and the packed bed B are violently disturbed, and the SS trapped in the filter media is removed from the filter media. Next, when the sludge outflow valve 9 at the bottom of the device 1 is opened and the water in the device 1 is drained, SS is discharged out of the system with the downward flow of water generated. At this time, the filter media a in the packed bed A and the filter media b in the packed bed B are prevented from flowing out of the system because they are blocked by the porous water-permeable member 2 and the porous water-permeable member 3.

Another effective cleaning method will be described. Similar to the above, first, the raw water supply valve 6 is closed to stop the supply of the raw water from the raw water supply pipe 5, and then the sludge at the bottom of the device 1 is blown into the device 1 by vigorously blowing air from the air diffusers 12 and 15. The outflow valve 9 is opened, the water in the device 1 is drained, the water is discharged from the sludge outflow pipe 8 to the outside of the system, and the water level in the device 1 is lowered to the vicinity of the position of the porous water passage member 3. Thus, the cleaning inside the packed bed B is completed. Then sludge outflow valve 9
Closed, the raw water supply valve 6 is opened to restart the supply of raw water,
Next, when the valve 19 for intermediate drainage is opened, S in the packed bed A
S flows out of the system from the intermediate drainage pipe 18 due to the upward flow of raw water and the disturbing action of air. When the water discharged from the intermediate drain pipe 18 becomes almost clear, the intermediate drain valve 1
Close 9 After a while, clear filtered water begins to flow out from the filtered water outflow pipe 22 in the upper part of the device 1.

To summarize the configuration of the important device of the present invention,
The following three points. The packed bed A and the packed bed B are divided by a net, a porous water-permeable member such as a punching plate or a grating. This is to prevent the filter media in the packed bed A and the packed bed B from being mixed. Filtration chamber D divided by three porous water permeable members of porous water permeable members 2, 3 and 4, packed bed A provided therein, filtration chamber E and packed bed provided therein In B, there is always a space in each filtration chamber.
The presence of these spaces enables the packed bed to swell during cleaning or the like. The particle size d ₁ of the filter medium a is larger than the particle size d _{2 of the} filter medium b. Under this condition, a large SS trapping capacity can be realized.

[0017]

EXAMPLES Examples carried out by the upflow filtration apparatus of the present invention are shown below. However, the present invention is not limited to this description.

Group groundwater (SS 180 mg / liter, B
The performance test of the upflow filtration apparatus of the present invention was conducted for OD 150 mg / liter). The filtration speed is 240m
/ Day (upstream flow) was performed at a constant speed. (Example 1) Filling layer A was filled with polygonal polyurethane foam having a particle size of 10 × 25 × 25 mm to a layer thickness of 1 m, and filling layer B was filled.
Then, spherical expanded polystyrene having a particle diameter of 2 mm was filled to a layer thickness of 1 m. (Comparative Example 1) Particle size 10 × 25 × in both packed layers A and B
It was filled with 25 mm square polyurethane foam. The layer thickness was set to 1 m for each of A and B. (Comparative Example 2) Both of the packed layers A and B were filled with spherical expanded polystyrene having a particle diameter of 2 mm. The layer thickness was set to 1 m for each of A and B.

The experimental results are shown in Table 1.

[0020]

[Table 1]

From Table 1, it can be seen that in the present invention, SS of treated water and filtration duration are superior to Comparative Examples 1 and 2.

[0022]

【The invention's effect】

(1) It is possible to provide a filtration device having a large SS trapping capacity. (2) By using two types of water floatable filter media, SS
Capturing capacity can be increased, there is no clogging, and filtration resistance can be reduced. (3) The coagulant can be used to coagulate SS in the device and the filtration resistance can be low. (4) It is possible to filter without mixing two types of water-floating filter media. (5) Not only physical filtration but also biological filtration can be performed. (6) The device can be easily cleaned in a short time.

[Brief description of drawings]

FIG. 1 is an explanatory diagram illustrating an example of an upflow filtration device of the present invention.

[Explanation of symbols]

1 Filtration device 2 Porous water-passing member 3 Porous water-passing member 4 Porous water-passing member 5 Raw water supply pipe 6 Raw water supply valve 7 Sedimentation sludge 8 Sludge outflow pipe 9 Sludge outflow valve 10 Coagulant addition pipe 11 Addition valve 12 Dispersion Air member 13 Gas supply pipe 14 Supply valve 15 Air diffuser 16 Air supply pipe 17 Supply valve 18 Intermediate drainage pipe 19 Drainage valve 20 Overflow weir 21 Filtration water drainage pipe 22 Filtration water outflow pipe 23 Outflow pipe valve A Packed bed B Packed bed C Settling area D Filtration room E Filtration room F Space area a Filter material b Filter material d ₁ Particle size d ₂ Particle size

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Claims (2)

[Claims] 1. A plurality of filtration chambers are formed by partitioning the inside of a tank with porous water-permeable members to form a plurality of filtration chambers, and a portion below the lowermost porous water-permeable member is a sedimentation section, and raw water is supplied to the sedimentation section. And a means for discharging the precipitate at the bottom of the tank, and a plurality of filtration chambers formed between the porous water-permeable members above the lowermost porous water-permeable member are buoyant to water and have an upper stage. In the filtration chamber, a packed bed filled with a filter medium of small particles in a floating state, and a space part is formed under the packed bed, and an aeration means is provided in the space part, and the treatment is performed above the uppermost porous water-passing member. An upflow filtration device, characterized by being provided with water outflow means. 2. The particle size of the filter medium filled in the lowermost packed layer of the filter medium is 5 mm or more and 60 mm or less, and the particle size of the filter medium filled in the uppermost packed layer is 0.5 mm or more and less than 5 mm. And the particle size of the filter medium packed in the upper packing layer of the adjacent filtration chambers does not exceed the particle size of the filter media packed in the lower packing layer. Filtration device.