JPH0824524A - Filter - Google Patents

Abstract

PURPOSE:To directly or indirectly give impact to a filter medium to strip SS that has been captured by providing a collision member on which a fibrous block filter medium collides when a filter bed is backward washed on the upper surface of the filter bed. CONSTITUTION:A filter bed 3 consisting of a fibrous block filter medium is formed on a lower water collecting plate 2 of a tank filter 1. A collision member 9 on which the fibrous block filter medium collides when the filter bed 3 is backward washed is attached. The collision member 9 may have an arbitrary form, but it occupies such a position that the filter medium collides with it properly and the flow thereof is not prevented. Then, on backward washing by air and washing water, the filter medium collides with the collision member 9 and also the filter medium come into collision is reoriented and collides with the other filter medium, allowing a lot of SS captured to be effectively stripped. Therefore, good washing effect is obtained, and the filter medium is used for a long period of time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high-speed filtration apparatus which contains a filter material made of fiber lumps in a filter layer and filters waste water discharged from sewage treatment facilities, factories of various industries as raw water.

[0002]

2. Description of the Related Art Hitherto, a filtering device having a filter layer made of sand, pebbles, anthracite or the like has been used for filtering water. However, in recent years, a block-shaped filter medium made of synthetic fibers has been developed as a filter medium capable of performing a filtration process at a higher speed, and a filter layer is constituted by the filter medium to perform the filtration process. This fibrous bulky filter medium is formed by bundling a large number of crimped yarns of ultrafine chemical fibers such as polypropylene, nylon, vinylidene chloride, acryl, acrylonitrile, etc. at the center and having a spherical shape as a whole with a large porosity of 1 to 10 cm. It has various sizes and is characterized by a large porosity of fibers and a large specific surface area. Due to the large porosity, it holds more suspended substances (SS) to be removed in raw water than conventional sand etc. In addition to being able to do so, the water flow resistance is small even if the water flow speed is high, so the conventional filtration speed using sand etc.
The filtration can be performed at a water flow rate of about 5 times (m / h). Also, due to its large specific surface area, SS in raw water
Can adsorb more than sand.

[0003]

However, due to the large porosity of the filter medium and the fact that the size of the block of the filter medium is much larger than that of grains such as sand, air and washing water are not removed from the filter medium during backwashing. Since it flows in the voids, it is difficult to fluidize, and the effect of SS separation due to the collision of the filter media becomes insufficient. In order to make the filter material that is hard to fluidize sufficiently flow, it is necessary to use a large volume of air having a flow velocity 5 to 50 times that of a conventional sand filter, which requires a large volume blower. Therefore, equipment cost and operating cost increase.

[0004]

Therefore, the present invention was developed for the purpose of enhancing a sufficient cleaning effect without using a large volume of air. In the filtering apparatus according to the item (1), a collision member against which the fibrous bulky filter medium collides during backwashing of the filter layer is provided on the upper surface of the filter layer. According to a second aspect of the present invention, in a filtering device including a filter material containing a fiber-shaped block material, the fiber filter material collides with the filter layer during backwashing, and a collision tube provided with an extraction hole through which liquid can be withdrawn is filtered. It is characterized in that it is provided on the upper surface of the layer, and a drain pipe for draining the liquid to the outside of the tank is connected to the collision pipe.

[0005]

EXAMPLES In each of the examples shown in the drawings, 1 is a filtration tank, 2 is a lower water collecting plate, 3 is a filter layer composed of a fibrous bulky filter medium on the lower water collecting plate, and raw water is provided at the top of the filtration tank. The introduction pipe 4 is connected to the backwash drainage and the backwash air discharge pipe 5, and the treated water outlet pipe 6 and the wash water supply pipe 7 are connected to the bottom. Further, on the lower surface of the lower water collecting plate 2, there is provided a blower as an air source and a backwashing air supply pipe 8 connected to an air compressor. These are well-known as a downward flow type filtration device, and in order to perform a filtration operation, raw water is supplied from a raw water introduction pipe 4 to cause a downward flow in the filter layer 3, and at that time, SS in the raw water is removed. It is captured by the filter layer and removed from the raw water, and the treated water is taken out from the take-out pipe 6.

In the embodiment of claim 1 of FIGS. 1 and 2, the filter layer 3
Above the above, there is provided a collision member 9 against which the fibrous bulky filter medium collides when the filter layer is backwashed. Even if the collision member 9 is rod-shaped,
The plate may have a vertical plate shape, and its planar shape may be an arbitrary shape such as a radial shape as shown in FIG. 2 as long as it does not stop the movement of the filter medium during backwashing. The position where the lower surface of the collision member 9 separates from the upper surface of the filter medium must be a position where the filter medium collides favorably during backwashing and at the same time does not hinder the flow of the filter medium. Although it is appropriately determined based on the amount of air in the case of, the upward development height H of the filter layer during backwashing is usually about 120 to 130% of the layer height h of the filter layer. The range is from directly above to about 20 to 30% above the height of the filter layer. If the collision member is provided within this range, the collision member is not limited to one stage, and may be provided in multiple stages in the vertical direction.

As described above, when the collision member 9 is provided above the upper surface of the filter layer 3 within a height range of about 20 to 30% of the height of the filter layer, the filter material is backwashed with air or cleaning water. Collides with the colliding member, the filter medium colliding with the colliding member changes its direction and collides with another filter medium, and the filter medium efficiently separates a large amount of captured SS.

[0008] In a filtration tank having a diameter of 600 mm and a height of 2500 mm, Bio-Ball (particle diameter 40 mm), a trademark of Kureha Chemical Co., Ltd., is used as a fibrous lump filter medium, and the layer height is 1000 mm.
10 p of SS having iron hydroxide as a main component constituting the filter layer of
Raw water containing pm was passed at a flow rate of 14 tons / hour, and a filtration step was performed. SS in treated water after 7.5 hours of filtration is about 1
It was ppm. After the filtration step, the backwash step was performed under the following conditions. Backwash with water 8 tons / hour 5 minutes with upward flow Backwash with air 550 Nm ³ / hour 15 minutes with upward flow Backwash with water and air 8 tons / hour (water) 15 minutes upward Flow: 550 Nm ³ / hour (air) 15 minutes Washing with water Downflow: 14 tons / hour 5 minutes

After performing the filtration process and the backwashing process 3 times, 4
In the second filtration step, after passing water unless a collision member is provided.2.
The SS of the treated water was about 5.4 ppm in 4 hours, and the performance was significantly lower than the initial value of 7.5 hours of water passage and 1 ppm of the treated water.

When the 18 stainless steel rods having a diameter of 8 mm and a length of 150 mm are attached to the inner periphery of the filtration tank at a distance of 50 mm from the upper surface of the filtration layer toward the center at equal intervals, to form a collision member, After passing water in the fourth filtration step, 6.5
The SS of the treated water was about 1.5 ppm even after the passage of time.

Further, the same stainless steel round bar is located above the upper surface of the filter layer, 9 at 200 mm and 9 at 50 mm.
When the collision members are attached to the inner periphery of the filtration tank at equal intervals toward the center, after the water is passed in the fourth filtration step, 6.
The SS of the treated water was about 1.4 ppm even after 7 hours had passed.

The above results indicate that, without the impingement member, the SS block trapped inside the fibrous bulky filter medium even after the backwashing step was performed.
Could not be sufficiently peeled off, and SS was put inside every time the filtration process was performed.
Indicates that it gradually accumulates and its performance deteriorates, and then it flows out into the treated water. On the other hand, when the collision member is provided, the SS trapped inside the filter material in the backwashing process is sufficiently peeled off, which means that the amount of outflow into the treated water during the filtering process is small.

In the embodiment of claim 2 shown in FIGS. 3 and 4, above the filter layer, a fibrous bulky filter medium collides with the filter layer during backwashing, and an extraction hole 11 through which the liquid in the tank can be withdrawn is formed. The collision pipe 10 provided is provided, and the drain pipe 12 is connected to the collision pipe. The plane shape of the collision tube 10 may be any shape as shown in FIG. 4 as long as the movement of the filter medium is not stopped and blocked during the backwash. The diameter of the collision pipe 10 needs to be a diameter sufficient to allow water or air for backwashing to flow out of the filtration tank through the drain pipe 12, and the treated water take-out pipe 6 and the washing water are required. The diameter of the pipe is about the same as that of the supply pipe 7. Further, it is preferable that the diameter of the extraction hole 11 is from 3 mm to about 1/2 of the particle diameter of the filter medium, and the total opening area thereof is equal to or larger than the cross-sectional area of the collision tube.

Also in this case, the position where the lower surface of the collision tube 10 separates upward from the upper surface of the filter medium is a position where the filter medium collides well during backwashing and at the same time does not hinder the flow of the filter medium. It is necessary and appropriately determined based on the amount of air at the time of backwashing, but the upward development height H of the filter layer at the time of backwashing is
Usually, it is about 120 to 130% of the layer height h of the filter layer, so the range is from directly above the upper surface of the filter layer to about 20 to 30% above the layer height of the filter layer. If the collision tubes are provided within this range, the collision tubes are not limited to one step, and may be provided in multiple steps in the vertical direction.

In this way, if the collision tube 10 is provided above the upper surface of the filter layer 3 within a height range of about 20 to 30% of the layer height of the filter layer, the filter medium is used when backwashing with air or washing water. Collides with the collision tube, the filter medium colliding with the collision tube changes its direction and collides with another filter medium, and the filter medium efficiently separates a large amount of the captured SS. Then, the SS separated from the filter medium by opening the valve of the drain pipe 12 flows into the collision pipe through the extraction hole together with the liquid in the tank, and is discharged to the outside of the tank by the drain pipe 12.

[0016] In a filtration tank having a diameter of 600 mm and a height of 2500 mm, a bio-ball (trade name: 40 mm), which is a trademark of Kureha Chemical Co., Ltd., is used as a fibrous block medium, and a layer height is 1000 mm.
Of the SS containing aluminum hydroxide as the main component
Raw water containing 0 ppm was passed at a flow rate of 14 tons / hour, and a filtration step was performed. The SS in the treated water after the filtration process for 4.5 hours was about 2 ppm. After the filtration step, the backwash step was performed under the following conditions. Backwash with water Upflow 8 tons / hour 5 minutes Backwash with air Upstream flow 480 Nm ³ / hour 15 minutes Combined use of water and air Backwash 8 tons / hour (water) 10 minutes Upflow Flow: 480 Nm ³ / hour (air) 10 minutes Washing with water 14 tons / hour 5 minutes with downward flow 5 minutes After the filtration process and the backwashing process were performed 3 times, the collision tube is not provided in the 4th filtration process. After 2.4 hours, the SS of the treated water was about 6.4 ppm, and the initial value was 4.
The performance was significantly reduced for 5 hours compared to SS2ppm in the treated water.

A pipe having a diameter of 65 mm and the same diameter as the take-out pipe 6 of treated water is arranged at a position of 200 mm above the upper surface of the filter layer in the diameter direction, and an extracting hole 12 having a diameter of 10 mm is provided in the pipe.
70 were opened as a collision tube, and the same filtration step as described above was performed three times, and the backwash step was performed under the following conditions after the filtration step. Water and an 8 ton / hr in combination backwash upflow of air (water), in upflow (drainage pipe closed) 480 nm ³ / hr (air) ....... backwash upward by 2 minutes air Flow 480 Nm ³ / h 8 minutes (drain pipe closed) Backwash with combined use of water and air 8 ton / h (water) with upward flow, upflow (drain pipe open) 480 Nm ³ / h (air) ...・ ・ ・ ・ ・ 7 minutes Washing with water 14 tons / hour for downflow 3 minutes (drain pipe open) Washing with water 14 tons / hour for downflow 5 minutes (drain pipe closed) Fourth filtration in this case In the process, the SS of the treated water was about 2 ppm even after 4.2 hours had passed, and the performance equivalent to that when the filter medium was in a new state was obtained. This means that the filter material collided with the collision tube, the SS captured by the filter material was almost completely separated directly or indirectly, and the separated SS was discharged to the outside of the tank by the drain pipe 12.

The applicant of the present invention effectively removes and removes the SS captured by the fibrous lump filter medium by backwashing. Therefore, the fibrous lump filter medium and a smaller size thereof and a terminal velocity in water are used. JP-A-6-79108 proposes to form a filter layer by mixing a granular material having rigidity close to the terminal velocity of a fibrous lump filter medium, for example, pebbles or rubber particles.
Further, for the same purpose, a partition plate for partitioning the area of the water collecting plate into a plurality of sections is attached downward to the lower surface of the lower water collecting plate supporting the filter layer on the upper surface, and an air supply pipe for backwashing is provided. The present inventor has developed that a sufficient cleaning effect can be obtained without using a large amount of air by providing back-washing with air in each of the sections provided in order under each section, and this is a patent application. Flat 5-219188
Proposed in the issue.

When the present inventions of claims 1 and 2 are carried out in combination with the above-mentioned prior proposal, the cleaning effect of backwashing can be further improved.

[0020]

According to the first aspect of the present invention, the fibrous bulky filter medium is caused to collide with the collision member during backwashing, and collide with the collision member,
The changed filter media violently collides with other filter media, thus directly and indirectly impacting the filter media, effectively removing the SS captured by the filter media, enhancing the cleaning effect of the filter media, and enabling long-term use of the filter media. In addition, the processing efficiency of filtration can be improved.
Further, according to the second aspect, the SS separated from the filter medium at the time of backwashing is immediately discharged out of the system, so that the cleaning effect of the filter medium can be further enhanced as compared with the first aspect.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an embodiment of the filtration device of claim 1.

2A to 2C are three examples of the planar shape of the collision member of FIG.

FIG. 3 is a cross-sectional view of an embodiment of the filtration device of claim 2.

4A to 4C are three examples of the planar shape of the collision tube of FIG.

[Explanation of symbols]

 1 Filter Tank 2 Lower Water Collection Plate 3 Filtration Layer 4 Raw Water Intake Pipe 5 Backwash Discharge Pipe 6 Treated Water Outtake Pipe 7 Wash Water Supply Pipe 8 Backwash Air Supply Pipe 9 Collision Member 10 Collision Pipe 11 Extraction Hole 12 drainage pipe

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display part 540 A 29/38 520 A 540

Claims (2)

[Claims] 1. A filter device comprising a fibrous lump filter medium in a filter layer, wherein a collision member against which the fiber lump filter medium collides during backwashing of the filter layer is provided on the upper surface of the filter layer. 2. A filter device comprising a fibrous bulky filter medium in a filter layer, wherein the fibrous bulky filter medium collides during backwashing of the filter layer, and a collision tube provided with an extraction hole capable of draining the liquid is used as the filtration layer. A filtration device, which is provided on the upper surface of the tank, and is connected to a drain pipe for draining liquid out of the tank to the collision pipe.