JPH01171693A - Biomembrane filtration apparatus - Google Patents

Abstract

PURPOSE:To prevent clogging, etc., of a biomembrane filtration apparatus by forming a fluidized bed of a filter medium to a downward passage of feed water to be fed and purifying the feed water by the biomembrane formed on the filter medium. CONSTITUTION:Feed water fed to a downward passage 2 from a feed water pipe 9 is purified by the biomembrane on the filter medium while the water passes through a fluidized bed A, and purified and freed of SS by the biomembrane by passing through a fixed bed B thereafter. The water flows then upward through an upward passage 3 and discharged as treated water from a discharging part 10 of the treated water. The filter medium forms the fixed bed B in the first stage by settling downward successively by the deposition of SS constituting the fluidized bed A in the first stage. The filter medium X for the fixed bed B is drawn out through a filter medium drawing pipe 5 or a filter medium drawing passage 12 out of the treating system. After it is separated from filthy water contg. SS in a separator 7, it is returned to the downward passage 2 through a filter medium returning means 8, and forms the fluidized bed A again. By this constitution, long time operation is possible.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a biofilm filtration device.

[Conventional technology and its problems]

A so-called biofilm filtration device is used as a pretreatment device for raw water for tap water. Figure 3 shows an example.
A filter layer 1 filled with granular filter media in the middle part of the tank 15
6 (fixed bed), and by this filtration Rg16, SS (
In addition to filtering suspended solids), a biofilm is formed on the filter medium, and the biofilm biologically purifies the raw water. Biological purification is performed by passing through the filter layer, and the treated water that has passed is extracted from the extraction pipe 17.

However, in such conventional devices, when operated for a certain period of time, the filtration resistance increases due to the SS trapped in the filter medium, and therefore, backwashing processing (air and backwash water from the backwash piping 18) is periodically performed. However, for this backwashing process, it is necessary to stop the supply of raw water, that is, to stop the operation.

In addition, in the above-mentioned backwashing process, there is a drawback that the filter material is blown upward during air washing (air supply) performed to separate the SS from the filter material, and flows out of the tank from the trough 19 etc. .

Further, when a filter medium outflow prevention net is provided to prevent such a filter medium outflow, there is a problem that the net becomes clogged.

The present invention was developed in view of these conventional problems, and eliminates the need to stop operation for cleaning filter media, and also prevents problems such as filter media flowing out of the tank and clogging of the filter media spill prevention net. It is an object of the present invention to provide a device which does not cause the formation of biological purification and which has a particularly excellent biological purification effect compared to conventional devices.

(Means for Solving the Problems) For this reason, the present invention particularly uses a filter medium with a specific gravity of less than 1, first forms a fluidized bed (a layer in which the filter medium is suspended in raw water) with the same filter medium, and then By forming a fixed bed with the settled filter medium after settling due to the adhesion of SS components, raw water is treated with two filtration layers, a fluidized bed and a fixed bed, and moreover, the raw water is sequentially extracted from the fixed bed to the outside of the filter medium tank. , after removing the attached SS.

The liquid is returned to the tank to form a fluidized bed again.

That is, the present invention has a treatment tank that has a downward flow path and an upward flow path that are connected to each other at the bottom of the tank, and a treated water discharge section is provided in the upper flow path, and raw water is supplied to the downward flow path. A raw water supply means, a filter material with a specific gravity of less than 1 charged into the tank to form a fluidized bed in the downward flow path, and a fixed bed formed by settling at the bottom of the tank due to the adhesion of SS components. A filter medium extraction means for extracting the filter medium out of the tank, a separation device for separating the extracted filter medium from wastewater containing SS components, and a filter medium for returning the separated filter medium to the downward flow path. Its basic feature is that it consists of a return means.

[For production]

According to the device of the present invention, a fluidized bed is formed by the filter medium in the downward channel to which raw water is supplied, and the raw water is purified by the biofilm of the filter medium. Although this fluidized bed does not have a filtration effect on the SS content, the SS content in the raw water gradually adheres to the filter medium, increasing its substantial specific gravity, and settling at the bottom of the tank to form a fixed bed (filtration layer). Since this fixed bed closes the communication part between the downward flow path and the upward flow path at the bottom of the tank, the raw water flowing downward enters the upward flow path after passing through the fixed bed. Then, the raw water is purified by the biofilm of the filter medium in this fixed bed, and
The SS portion is filtered. After leaving the fixed bed, the treated water ascends through the upward flow path and is then discharged from the treated water discharge section to the outside of the tank.

On the other hand, the filter media forming the fixed bed are sequentially extracted out of the tank by the filter media extracting means, washed if necessary, and then separated from the wastewater containing the SS content by a separation device. Then, the filter medium is returned to the downward flow path of the processing tank by the filter medium return means, and this filter medium forms a fluidized bed again.

In this way, in the device of the present invention, the filter medium circulates inside and outside the tank through the following route: fluidized bed formation → fixed bed formation → extraction from the tank, return to the SS separation tank → fluidized bed formation. No washing process is performed. Furthermore, since the raw water passes sequentially through a fluidized bed and a fixed bed formed by the same filter medium, the purification effect of the biofilm can be particularly effectively obtained.

〔Example〕

FIG. 1 shows an embodiment of the present invention.

In the figure, 1 is a processing tank, and the processing tank 1 has a partition wall 4.
Thus, a downward flow path 2 is formed in the center, and an upward flow path 3 is formed outside of the downward flow path 2, and both flow paths communicate with each other at the bottom of the tank. Further, the bottom of the treatment tank 1 is configured in a grove shape.

A treated water discharge section 10 for overflowing treated water is provided at the upper part of the upward flow path 3.

Reference numeral 5 denotes a filter medium extraction pipe, one end of which is connected to the bottom of the tank in the form of a forest. A pump 11 is provided in the middle of this piping 5.

7 is a SS for the filter medium extracted by the filter medium extraction pipe 5.
This is a separation device for separating wastewater from contaminated water. As this separation device 7, for example, a vibrating screen or the like is used. Note that, if necessary, a filter medium cleaning device 6 may be provided upstream of this separation device 7.

Reference numeral 8 denotes a filter medium return means for returning the resin separated from the wastewater by the separator 7 to the downward passage 2 of the treatment tank 1.

9 is a raw water supply pipe for supplying raw water to the downward flow path 2.

The granular filter medium (X) used in the present invention has a specific gravity of less than 1, and this filter medium is initially charged into the downward flow path 2,
A fluidized bed (A) is formed by the downward flow of raw water. Also,
The filter medium that had formed the fluidized bed settles to the bottom of the tank due to the adhesion of the SS component, and forms a fixed bed (B) that blocks the communication portion between the downward flow path 2 and the downward flow path 3. Therefore, it is necessary to charge the tank with enough filter media to form the fluidized bed (A) and fixed bed (B) as described above.

FIG. 2 shows another embodiment of the present invention, in which the lower end is fixed between the downward flow path 2 and the upward flow path 3 by a partition wall 13 instead of the filter medium extraction pipe shown in FIG. A filter medium extraction channel 12 opened facing the floor (B) is provided, and an air pipe 1 is installed in this channel 12.
4, and the filter medium (X) is drawn out of the tank by the upward flow caused by the air supply.

According to the apparatus of the present invention as described above, the raw water supplied from the raw water supply pipe 9 to the downward flow path 2 passes through the fluidized bed (A) and is purified by the biofilm of the filter medium, and then passes through the fixed bed (A). By passing through B), the water is purified by biofilm and the SS content is filtered, and then ascends through the upward flow path 3 and is discharged from the treated water discharge section 10 as treated water.

In addition, the filter medium initially forms a fluidized bed (A), but
Due to the adhesion of the SS component, it gradually settles downward to form a fixed bed (B). The filter medium (X) in the fixed bed (B) is extracted to the outside of the tank through the filter medium extraction pipe 5 or the filter medium extraction channel 12,
After being separated from wastewater containing SS in the separator 7, it is returned to the downward flow path 2 through the filter medium return means 8, and then returned to the fluidized bed (A
) to form.

〔Effect of the invention〕

According to the present invention described above, there are the following advantages.

■During operation, the filter media can be taken out of the tank one by one, washed, and then returned to the tank, so there is no need to stop the operation and perform backwashing, allowing continuous operation for long periods of time. Can be done.

■Since there is no backwashing process, problems such as leakage of filter media and clogging of the leakage prevention net do not occur.

■The same filter media forms a fluidized bed and a fixed bed in the tank, and raw water is treated by these two layers of filter media, so that particularly effective purification by biofilm can be achieved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing one embodiment of the present invention. FIG. 2 is an explanatory diagram showing another embodiment of the present invention. FIG. 3 is an explanatory diagram of a conventional device. In the figure, 1 is a processing tank, 2 is a downward flow path, 3 is an upward flow path, 5 is a filter medium extraction pipe, and 7 is a separation device. 8 is a filter medium return means, 9 is a raw water supply pipe, IO is a treated water discharge section, 12 is a filter medium extraction channel, and (A) is a fluidized bed. (B) is a fixed bed, and (X) is a filter medium. Figure 1

Claims (1)

[Claims] A treatment tank having a downward flow path and an upward flow path communicating at the bottom of the tank, and a treated water discharge section provided in the upper flow path, and a raw water supply means for supplying raw water to the downward flow path. Then, the filter material with a specific gravity of less than 1 was charged into the tank to form a fluidized bed in the downward flow path, and the filter material that had settled at the bottom of the tank due to the adhesion of SS components and formed a fixed bed was removed from the tank. a filter medium extracting means for extracting the filter medium;
A biofilm filtration device comprising: a separation device for separating extracted filter media from wastewater containing SS components; and a filter media return means for returning the separated filter media to the downward flow path.