JPH07108361B2 - Clarification device for suspension and cleaning method thereof - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel filtration device for treating a suspension containing SS and a method for cleaning the same. The term "filtration" as used herein includes, in addition to normal filtration, a biofiltration treatment method in which air or the like is supplied to treat as in the case of biochemical treatment.

[0002]

2. Description of the Prior Art Upflow filtration devices using a sponge-like elastic porous granular material as a filter medium have hitherto been disclosed in JP-A-60-14720.
No. 7 publication.

As shown in FIG. 2, this prior art is based on raw water 2
By passing 0 in an upward flow, the sponge granules 19 are compressed on the lower surface of the net 18, the porosity of the sponge granules filter medium is reduced, and filtered water 23 is obtained. This is a technique of supplying the cleaning air 22 to the filter layer to clean the filter medium.

However, as a result of carrying out a supplementary test of this prior art, it was found that there were the following serious drawbacks.
Since SS is filtered off with the sponge compressed to reduce the porosity, the filter layer is severely clogged with SS in a short time after the start of filtration, and the filtration resistance rapidly increases. For this reason, the filter bed must often be washed.

The filtration layer is washed by supplying air and washing water from the bottom in an upward flow, but at this time, the sponge particles are pressed against the lower surface of the mesh more and more strongly, and the filter medium cannot be fluidized. It is very difficult to wash the filter media.

In the prior art, as a cause of such a defect, as shown in FIG. 2, a floating preventing net 18 is provided in contact with an upper portion of a packed layer of a granular material such as sponge which is easily compressed. Therefore, the pressure of the upward flow of raw water causes the sponge to be strongly compressed to the lower surface of the mesh, which makes it easier for SS to become clogged, resulting in a sharp increase in filtration resistance, and the sponge granules are increasingly compressed, creating a vicious cycle. confirmed.

That is, in the prior art, the technical idea itself of filtering SS with the packed layer of the sponge granular material being compressed has a practical problem. Therefore, the conventional technique cannot be an excellent filtration technique.

[0008]

SUMMARY OF THE INVENTION The object of the present invention is to completely solve the drawbacks of the above-mentioned conventional apparatus, and has a large SS trapping capacity, a small increase in filtration resistance, and It is an object of the present invention to provide a novel filtration device that is easy to clean and a cleaning method thereof.

[0009]

Means for Solving the Problems The present invention is a packed bed of resilient porous granules arranged in the tank, a porous water passage member provided in the upper part of the packed bed, the upper portion of the multi Anadori water members Wash drain outflow
Is provided, and the lower part of the porous water-permeable member is
Reducing wash drainage pressure on elastic porous granules
In order to provide at least a part of the cleaning drainage water, a cleaning drainage outflow portion is provided, and a raw water inflow portion is provided above the packed bed, and a filtered water outlet, a cleaning water supply portion, and a cleaning air supply portion are provided below the packed bed. And a valve for opening and closing the washing drainage outlet of the lower part of the porous water-passing member, and a clarification device for a suspension, and a method for cleaning the clarification device described above, wherein: Water and air are supplied from the cleaning water supply unit and the cleaning air supply unit to clean the packed bed, and the elastic porous particles at the time of cleaning
The porosity to reduce the pressure of the wash drain on the
Less cleaning drainage from the cleaning drainage outlet below the water passage member
Both of them are a method for cleaning a clarification filtration device, which is characterized in that a part thereof is discharged, and the above problems can be solved by this.

The device of the present invention is characterized in that a packed bed made of elastic porous granular material is used as a filtration layer in a tank, and the suspension is filtered and clarified by a downward flow. A porous water-permeable member for introducing a suspension is provided in the portion, and a washing drainage outflow portion is provided above the porous water-permeable member.
Cleaning of the elastic porous granular material at the time of cleaning
At least one of the wash effluent to reduce the pressure of the effluent
Part of the detergent drain outlet section for outlet provided, in further deployed the valve to the washing water discharge outlet of the lower portion.

That is, the apparatus of the present invention is a filtration apparatus in which a packed bed is operated in a downward flow, and the porosity of the packed bed can be kept extremely high, the filtration time can be maintained for a long time, and the cleaning can be effectively performed. The lower part of the porous water-permeable member
Reducing wash drainage pressure on elastic porous granules
Maximum is characterized, thereby, filterability without SS remains in packed bed the valve provided with a cleaning water discharge outlet portion for discharging the at least a portion of the detergent drain that is arranged for
The force can be kept high to increase the processing efficiency of the suspension.

Further, the cleaning method of the present invention is characterized in that by operating the above-mentioned device, the above-mentioned porous water-passing member is provided with an upper part .
This is to stipulate the timing of discharge of cleaning wastewater and the adjustment of the water level to each of the cleaning wastewater outlets located in the lower part .
That is, when the packed bed is washed while increasing the amount of water and air, the elastic porous particles flow, and while being washed, they are gradually pressed against the porous water-permeable member to compress the elastic porous particles. During this period, the cleaning wastewater is discharged from the upper portion of the porous water-permeable member. However, in the conventional method, this compression state was maintained for a considerably long time, so that SS could not be sufficiently removed. By opening a valve of the cleaning drainage outlet provided in the lower portion of the water member, the cleaning drainage is discharged from the cleaning drainage outlet of this lower portion , thereby lowering the porous water passage member.
It is possible to reduce the amount of cleaning wastewater flowing upward from one side.
Come, thereby to compress the resilient porous granules is opened, it is possible to improve the discharge of cleaning and SS elastic porous granules. At that time, the water level in the apparatus lowers accordingly.
In the present invention, the position where the porous water-permeable member, and consequently the washing drainage outflow portion, is provided is the upper portion of the packed bed. Here, it is preferable to provide a space between the upper end of the packed bed and the porous water-permeable member for more effective cleaning.

The position of each of the upper and lower wash drainage outflow portions is not particularly limited. In the case of the upper part, the porous water-passing member is slightly above, and in the case of the lower part, the porous water-passing member is located 30
A position below about 50 cm is preferable.

The porous water-permeable member used in the present invention has a structure that prevents the flow of the elastic porous particles out of the system, allows expansion of the packed bed, and can fix and hold the packed bed.
The configuration is arbitrary and is not particularly limited. For example,
Known materials such as nets and perforated plates having pores smaller than the particle size of the elastic porous granular material can be mentioned.

The elastic porous granules used in the present invention are:
When it is compressed under atmospheric pressure, it shrinks by removing the internal air, and when it stops compression, it is a porous small body that has elasticity and is restored to its original state. Any shape, material, hole structure, etc. can be applied.

The elastic porous granular material is most preferably one having a three-dimensional network structure formed so as to have continuous holes from the surface to the inside, and can be produced by a known foaming method or the like. The material of the elastic porous granular material is not particularly limited as long as it has the above-mentioned properties, and an organic polymer,
Known materials such as inorganic compounds can be used, but among them, a material having appropriate elasticity and strength as the material itself is preferable, and a urethane resin is particularly preferable.

For example, an elastic porous granular material such as polyurethane foam is produced by foaming plastics such as urethane resin by a foaming method for producing continuous cells, and is used as it is or cut into a desired shape and size for use. .

The size of the elastic porous granules is from 10 to 30.
mm, and the shape can be square, spherical, and various other shapes, but the square is preferable. Its specific gravity is usually 0.8
About 1.2 is preferable.

The porosity of the elastic porous granular material is preferably 90% or more. Moreover, the pore diameter, that is, the hole diameter is 0.1 to 6
It is desirable to select from the range of mm, preferably 1-4 mm. The number of holes per 1 cm length is 5 to 2
0 is preferable.

In the apparatus of the present invention, the raw water inflow portion is provided above the packed bed, and at least the filtered water outlet is provided below the packed bed.
A cleaning water supply unit and a cleaning air supply unit are provided in the tank, and conventionally known devices can be applied to these devices. These devices are composed of known conduits, valves, pumps, blowers, etc., and their structures are arbitrary. Specifically, the cleaning water supply unit and the cleaning air supply unit are usually composed of a supply pipe having a hole, a pipe line, a valve, a pump, a blower, or the like. In addition, the filtered water outlet is usually located in a support that supports the packed bed, for example, in the case of a gravel layer, and in the lower part of a porous plate, etc. It is possible to secure the water level in the formation. In addition, the filtered water outlet, the cleaning water supply unit, and the cleaning air supply unit may be configured as a block structure.

The apparatus of the present invention is not limited to the physical removal of SS, but by supplying oxygen-containing bubbles to the packed bed to maintain aerobic conditions, the microorganisms are caused to adhere and propagate to grow. It is possible to form a biofilm on the surface to perform biological removal of at least aerobic biofilterable sewage components such as BOD, NH ₃ -N and physical removal of SS, for which oxygen-containing bubble supply. The device, that is, the air diffuser, can be arranged at an appropriate position such as a lower portion of the packed bed. This air diffuser may also be used as the cleaning air supply unit. Alternatively, it is also possible to maintain the inside of the tank under anaerobic conditions to provide an anaerobic biological filtration device. Further, a filtration device in which an aerobic filtration layer and an anaerobic filtration layer coexist in a single tank may be constituted by the packed bed.

When cleaning the device of the present invention, especially the packed bed
The cleaning drainage from the cleaning drainage outlet below the porous water-permeable member.
To drain at least a portion of the water ,
Above the porous water-permeable member by supplying water and air from the cleaning water supply unit and the cleaning air supply unit to clean the packed bed.
The discharge of the cleaning wastewater from the cleaning wastewater outflow part of the section and the opening and closing of the valve for opening and closing the cleaning wastewater outflow part at the lower part of the perforated water passage member are carried out to eliminate the compression of the filler by discharging at least a part of the cleaning wastewater. It is a cleaning method. The cleaning method of the present invention includes three methods using water, air, and water and air, which can be performed in various combinations, and water and air may be supplied at the same time or at different times. It is preferable to perform washing and draining once or more. these,
The timing of supplying water and air can be set freely, and it may be continuous or intermittent. Further, the timing of opening and closing the valve provided at the lower part of the porous water-passing member and the number of times of opening and closing during one cleaning step are such that compression due to cleaning drainage of the elastic porous granular material is eliminated, and SS discharge is not hindered. As long as it is operated like this, it can be set freely and the degree of water level drop is arbitrary.

In the cleaning method of the present invention, the amount of water or air to be supplied can be appropriately selected depending on the type of suspension, the degree of attachment of trapped SS, etc., but normally air is 1 to 2
The water content is preferably m ³ / m ² · min or less, and the water content is preferably 0.5 to 1 m ³ / m ² · min or less.

Since the cleaning method of the present invention can effectively perform cleaning, it is possible to reduce the ratio of generation of cleaning waste water (the ratio of using treated filtered water as cleaning water) as compared with the conventional cleaning method. It can be 10% or less.

Further, it is preferable to provide a member such as a net for preventing the outflow of the elastic porous granular material in the drainage part of the washing drainage outflow part under the porous water-permeable member.

[0026]

EXAMPLES Specific examples of the present invention will be described below, but the present invention is not limited thereto.

FIG. 1 illustrates the structure of a filtration device 1 of the present invention. Reference numeral 2 denotes a filtration tank in which a filling layer 3 of elastic porous particles (polyurethane foam particles) having a three-dimensional network structure is provided. As the filter material adopted in the present invention, various elastic porous particles can be applied,
A preferred example is one in which a polyurethane foam granular piece having a three-dimensional network structure (pore diameter 1 to 2 mm) (corner shape having a particle size of 10 × 25 × 25 mm) is filled in a filling layer thickness of 2 to 4 m.

When the above-mentioned packed bed is adopted, the particle size is 5 even though the porosity of the packed bed is extremely large at 97 to 98%.
It was experimentally confirmed that SS having a size of μm or more can be almost completely removed.

When applied to the filtration of sewage, it was confirmed that the filtration speed can be 500 to 1000 m / d and the generation ratio of washing wastewater can be 10% or less. 4 is a support floor such as gravel. A porous water-permeable member such as a net may be installed below the packed bed instead of the support bed 4. 5
Is a filtered water outflow pipe, which is provided upright near the upper interface of the packed bed. Reference numeral 6 is a raw water inflow portion, and reference numeral 7 is a porous water-passing member such as a net that removes coarse foreign matter and prevents the filter medium from flowing out when the packed bed is backwashed. Next, 8 and 9 are washing drainage outflow pipes, which are provided above and below the porous water-permeable member 7, with a valve 10 provided in the outflow pipe 9.

This structure is the main object of the present invention and is to break the vicious cycle of compression blockage that has been found in the conventional method. Further, a filter material outflow prevention member 11 such as a net is provided at the cleaning drainage outlet of 9. Next, 12 is a cleaning water supply pipe for cleaning and removing SS trapped in the packed bed at the end of filtration. Similarly, 13 is a cleaning air supply pipe.

The operation of the filtration device of the present invention will be described below. When a suspension such as sewage is supplied from the raw water inflow portion 6 to the upper portion of the porous water-permeable member 7, coarse foreign matter (leaf, rubber piece, hair, fiber, etc.) in the raw water is removed by the porous water-permeable member 7. . Then, the raw water flows into the packed bed of the elastic porous granular material in a downward flow, and the fine SS is filtered and trapped in the packed bed.

The treated water from which SS in the raw water is removed by filtration is
The filtered water outflow pipe 5 flows out of the system. Since the elastic porous granular material having a three-dimensional network structure such as polyurethane foam has an extremely high porosity of 97 to 98%, the SS trapping capacity in the packed bed is very large and the increase in filtration resistance is small.

However, as filtration is continued for a long time,
Since the amount of SS trapped in the packed bed reaches the limit, the filtration resistance rises, and the water level rises near the porous water-passing member 7,
At that point, the inflow of raw water is stopped and the packed bed is washed.

By washing the packed bed by the following method, the elastic porous particulate matter can be effectively washed. The valve 14 provided in the filtered water outflow pipe is closed. Valve 15 for washing water supply pipe and valve 16 for washing air supply pipe
Open and wash with water and air simultaneously. By cleaning water and air simultaneously, the filter media in the packed bed is water,
Due to the rising disturbing action of air, the SS that has flowed, vibrated, and was trapped is removed from the filter medium, and flows out from the cleaning drainage outflow pipe 8. At this time, coarse particles captured by the porous water-permeable member 7 are also washed out. When the above operation is continued, the packed bed floats upward due to the upward flow and contacts the lower surface of the porous water-permeable member 7. If the simultaneous washing of water and air is continued as it is, the filter medium is pressed against the porous water-permeable member 7 so that it does not flow and is compressed. Therefore, the valve 10 provided in the cleaning drainage outflow pipe 9 below the porous water-permeable member is opened. The cleaning waste water is allowed to flow out from the pipe 9. Then, whether the lower part of the lower surface of the water passage member 7
The pressure of the cleaning wastewater from these plants decreases (with this, the water level in the tank
Since reduced to), the filter medium is not pressed against the porous water passage member 7, will be better flow, cleaning can be performed effectively. During such cleaning, the lower surface of the water passage member 7
The method of releasing the pressure of the washing drainage from below and eliminating the compression blockage of the filter medium is a new technical idea that has not been known so far.

When the above operation is continued for 5 to 10 minutes, the SS trapped in the packed bed is sufficiently washed and removed. Therefore, the valves 15 and 16 are closed to stop the supply of washing water and empty washing air. The valve 14 for outflow of filtered water is opened, the valve 10 for outflow of cleaning waste water is closed, and the supply of raw water is started.

As a result, both the coarse foreign matter trapped on the porous water-permeable member 7 and the SS trapped in the packed bed can be effectively washed and removed. In the step of the cleaning method, it is also effective to open and close the valve 10 a plurality of times during one cleaning step to alternately flow the cleaning wastewater from the cleaning wastewater outflow pipe 8 and the cleaning drainage outflow pipe 9 to shake the filter medium. is there.

Further, the drainage of the cleaning drainage from the cleaning drainage outflow pipe 8 may be appropriately performed if necessary, and normally, the valve 10 may be opened at the beginning of the cleaning to perform the cleaning without compressing the filling filter medium.

When the filtration operation is performed while supplying the oxygen-containing gas 17 to the lower portion of the packed bed, microorganisms are immobilized on the filter medium, so that the aerobic biological treatment can be simultaneously performed.

[0039]

According to the present invention, the following important effects can be obtained and the drawbacks of the prior art can be solved. The filter medium can be effectively washed. Coarse foreign matter in raw water can be removed effectively, and its cleaning is easy. Little clogging of the filtration layer. Slow rise in filter resistance. High filtration rate can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram for explaining a specific example of a filtration device of the present invention.

FIG. 2 is a diagram illustrating a filtration device according to a conventional method.

[Explanation of symbols]

 1 Filtration device of the present invention 2 Filtration tank 3 Packed bed 4 Support bed 5 Filtered water outflow pipe 6 Raw water inflow part 7 Porous water passage member 8 Wash drainage outflow pipe 9 Wash drainage outflow pipe 10 Valve 11 Filter medium outflow blocking member 12 Washing water supply Pipe 13 Washing air supply pipe 14 Valve 15 Valve 16 Valve 17 Oxygen-containing gas 18 Net 19 Sponge granules 20 Raw water 21 Washing water 22 Washing air 23 Filtration water

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display C02F 3/06 3/10 A

Claims (2)

[Claims] 1. A packed layer of an elastic porous granular material is provided in a tank, a porous water-passing member is provided above the packed layer, and a cleaning drainage outlet is provided above the porous water-passing member. Porous water passage
The lower part of the material against the elastic porous particles during washing
Less wash drainage to reduce pressure
In addition to providing a washing drainage outflow part for outflowing a part, a raw water inflow part is provided above the packed bed, and a filtered water outlet, a cleaning water supply part, and a cleaning air supply part are provided below the packed bed. A clarification / filtration apparatus for a suspension, which is provided with a valve for opening / closing a washing / drainage outflow portion under the porous water-passing member. 2. The method for cleaning a clarification filtration apparatus according to claim 1, wherein water and air are supplied from the cleaning water supply unit and the cleaning air supply unit to clean the packed bed and the cleaning is performed.
Pressure of wash drainage on the elastic porous granules during
To reduce the flow
A method for cleaning a clarification filtration device, characterized in that at least a part of the cleaning waste water is discharged from the outlet .