JPH01139195A - Contact tank of biological filter - Google Patents

Abstract

PURPOSE:To easily prevent the outflow of a filter medium during backwashing by providing a filter medium outflow preventive device which abuts on the inlet of a pipe jointly used as the raw water inlet pipe and the backwashing water outlet pipe when the water level rises in a contact tank and which is separated from the inlet when the water level lowers to form a space. CONSTITUTION:When raw water is filtered, a space is formed between the inlet of a pipe 5a and the outflow preventive device 15, the raw water sent from the pipe 5a is introduced into a biological filter bed 3 in the contact tank 1, hence the impurities in the water are separated, and treated water is discharged from an outlet pipe 6. When the filter bed 3 is washed, backwashing water is injected from an inlet pipe 7, and the filter medium 4 is circulated and washed with the backwashing water. When the water level in the tank 1 rises due to the continuation of backwashing, a float 23 is actuated, the preventive device 15 is closely attached to the inlet of the pipe 5a, and the backwashing water is passed through meshes 18 and 19 from the upper part of the device 15 into the pipe 5a and discharged. The clogging of the meshes 18 and 19 is prevented by the washing balls 20 and 21 rolling on the meshes 18 and 19.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a contact tank for a biological filtration system for raw water using microorganisms, and more specifically, a contact tank equipped with a device for preventing outflow of furnace material during backwashing. The present invention relates to a contact tank.

[Prior art] Methods for biologically treating raw water drawn from rivers, lakes, etc. include the biological catalytic oxidation method using honeycomb tubes, the rotating disk method using rotating disks, and the fluidized bed. The fluidized bed method using a fixed bed or the fixed bed method using a fixed bed are well known.

Among these, biological filtration devices using the fixed bed method form a biological filtration bed using a furnace material consisting of a large number of carriers with microorganisms attached to the contact tank, and raw water flowing from the top of the contact tank passes through this biological filtration bed. The raw water is brought into contact with microorganisms, and various impurities in the raw water are removed through biological reactions and filtration and adsorption, and then taken out as treated water.

FIG. 6 is a schematic diagram showing an outline of the contact tank of the biological filtration device as described above. In the figure, 1 is a contact tank, and on the bottom plate 2, which has many small holes provided at the bottom, there is a contact tank with a diameter of, for example, 3.
The biological filtration bed 3 is made of a carrier such as activated carbon or sand, which has a specific gravity of ~5 mm and is the same as or slightly larger than water, V, and is made of a furnace material 4 to which microorganisms are attached. 5 is an inflow pipe for raw water provided at the top of the contact tank 1, 6 is an outflow pipe for treated water provided at the bottom of the contact tank 1, 7 is an inflow pipe for backwash water, and 8 is above the inflow pipe 5 for raw water. This is a backwash water discharge pipe installed at the top of the contact tank 1, as shown in Figure 7, and surrounded by a wire mesh 1.
0 is connected to the chamber 9 which is filled with air.

In the contact tank 1 configured as described above, raw water flowing into the contact tank 1 from the raw water inflow pipe 5 passes through the biological filtration bed 3 and is taken out as treated water from the water flow pipe 6 to the outside. At this time, the raw water passing through the biological filter bed 3 comes into contact with the microorganisms in the furnace material 4 and is biologically treated to remove impurities.

By the way, in such a biological filtration device, as the treatment progresses, the biological filtration bed 3 becomes clogged by suspended solids in the raw water and microbial flocs detached from the carrier, causing clogging and reducing the processing capacity. It is necessary to clean the filter bed 3 to remove clogging and to supply oxygen to the microorganisms.

For this reason, backflow water is spouted into the contact tank 1 from the backwash water inflow pipe 7, flows and cleans the P material 4 of the biological filter bed 3, and at the same time supplies oxygen to the microorganisms, and the backflow water after cleaning is is discharged to the outside from a discharge pipe 8 through a wire mesh 10. At this time, some of the P material 4 that has flowed in the contact tank 1 tries to flow out together with the backwash water, but this is blocked by the wire mesh IO provided in the chamber 9.

[Problems to be Solved by the Invention] In general, microorganisms attached to carriers are sticky, so the carriers fluidized by backwashing stick to the wire mesh of the discharge pipe, clogging it and making drainage difficult.

For this reason, the wire mesh must be taken out from time to time to be cleaned, which is extremely troublesome.

The present invention has been made in order to solve the above-mentioned problems, and provides a contact tank of a biological filtration device equipped with a device that can automatically clean the wire mesh for preventing the outflow of furnace material to prevent clogging. The purpose is to

[Means for Solving the Problems] The present invention has been made to achieve the above object, and includes a biological filter bed made of furnace material inside, and an inflow pipe for raw water and a backwash water pipe at the top. In a biological filtration device, the biological filtration device is equipped with a contact tank having a discharge pipe for raw water and an inflow pipe for raw water and a discharge pipe for backwash water at the top of the contact tank. At least one screen having a mesh smaller than the diameter of the furnace material is attached to the opening in the contact tank of the chain pipe, and at least one screen having a mesh smaller than the diameter of the furnace material is attached to the frame with openings at the top and bottom. An outflow preventer comprising a large number of cleaning balls having a diameter approximately equal to the diameter of the material is connected so as to be movable up and down, and when the water level in the contact tank rises, the inflow preventer comes into contact with the pipe, The present invention provides a contact tank for a biological filtration device equipped with a furnace material outflow prevention device configured to form a space between the two when the water level falls.

[Function] When treating raw water, a space is formed between the inlet of the pipe and the outflow preventer, so the raw water sent from the pipe flows through this space to the biological filter bed. Impurities are filtered out from the treated water outlet tube.

When cleaning the biological filter bed, backwash water is jetted out from the backwash water inflow pipe, and the furnace material is flushed and washed by the backwash water. As backwashing continues, the water level rises, so the spill preventer comes into close contact with the inlet of the pipe, and the backwash water flows from above the spill preventer into the pipe through the mesh and is discharged. As a result, the P material is prevented from flowing out by the net, and the cleaning balls on the net are rolled by the backflowing water, thereby preventing the net from clogging.

[Example] FIG. 1 is a schematic diagram of an example of the present invention. Note that the same or equivalent parts as in the conventional example explained in FIG. 6 are denoted by the same reference numerals, and the explanation thereof will be omitted. In the figure, numeral 11 is a furnace material outflow prevention device according to the present invention, an embodiment of which is shown in FIG. Second
In the figure, reference numeral 12 denotes a chamber, to which a pipe 5a that serves both for inflow of raw water and discharge of backwash water is connected. I5 is a P material outflow preventer formed in a sieve shape, and as shown in FIG. A frame 16 having an edge 17 that is slightly smaller than the outer circumference of the frame 16, and nets 18 and 19 stretched over the edge 17 and the top thereof.
It consists of a number of cleaning bulbs 20, 21 arranged above.

The meshes 18 and 19 have meshes (for example, 2 to 3 mm) that are slightly smaller than the diameter of the P material 4 (for example, 3 to 5+n).

Further, the cleaning bulb 20 arranged on the net 18 is formed from a hollow stainless steel bulb, glass bulb, etc. whose apparent specific gravity is smaller than 1 and whose outer diameter is equal to the diameter of the P material 4. The cleaning bulb 21 disposed above has an apparent specific gravity greater than 1,
It is formed from a hollow stainless steel bulb, glass bulb, etc. whose outer diameter is approximately equal to the diameter of the P material 4.

The spill preventer 15 configured in this way is placed on the chamber 12, and the links 22° 22a (
(also provided on the opposite side of the figure) to a shaft provided in the chamber 12. 23 is a float whose support arm 24 is connected to the link 22a, and 25 is a stopper for the float 23 provided in the chamber 12.

Note that 26 in FIG. 3 is a vibrator that vibrates the outflow preventer 15, but it is not essential to the present invention.

The operation of the present invention constructed as described above will be explained with reference to FIGS. 1 to 5. First, close the valve of the backwash water inflow pipe 7, open the valve of the treated water outflow pipe 6, and pour the raw water into the pipe 5a.
It is supplied into the contact tank 1 through the outflow prevention device 11.

At this time, since the water level in the contact tank 1 is low, the float 23 descends due to its own weight, comes into contact with the stopper 25, and stops. As a result, the outflow preventer 15 is moved upward by the parallel link that interlocks with the float 23. is pushed up to form a space between it and the chamber I2 as shown in FIG. As a result, the raw water flows out from this space into the contact tank 1, is filtered through the biological filter bed 3, and is taken out as treated water.

Next, in order to wash the biological body 2, the backwash water inlet pipe 7
When the valve of the treated water outlet pipe 6 is opened and the valve of the treated water outflow pipe 6 is closed, backwash water is jetted from the backwash water inflow pipe 7 into the contact tank 1, the furnace material 4 of the biological filtration bed 3 flows and is washed. At the same time, the water level of the backwash water rises, causing the float 23 to rise. As the float 23 rises, the outflow preventer 15 is pushed down by the parallel links interlocking with it, and the edge 17 comes into close contact with the chamber 12, as shown in FIG.

Therefore, the backflow water flows out from the upper opening of the outflow preventer 15 through the screen 18.19 and is discharged to the outside from the pipe 5a, and some of the furnace material 4 contained in the backwash water flows through the screen 18.19. 19 prevents the outflow. At this time, the cleaning balls 20, 21 move around on the net 18.19 due to the water pressure of the backwash water,
19 to prevent clogging. Note that if the outflow preventer 15 is vibrated by the vibrator 25 as necessary, the net 18.1
9, the prevention of clogging can be further promoted.

In the above explanation, the present invention is applied to a fixed bed type biological filtration device, but the present invention can also be implemented to a semi-fluidized bed type or fluidized bed type biological filtration device that requires backwashing. Can be done. In addition, although the case where two nets 18 and 19 are provided in the spill preventer 15 is shown, one or three or more nets may be provided.Furthermore, the spill preventer may be provided with a combination of parallel links and floats. Although an example of vertical movement is shown, other mechanisms may be used.

[Effects of the Invention] As is clear from the above description, according to the present invention, it is possible to prevent the outflow of filter media during backwashing with a simple structure, and moreover, it is possible to prevent the filter media from flowing out during backwashing with a simple structure. Clogging can be automatically prevented.

In addition, since the raw water inflow pipe and the backwash water discharge pipe are used as both, the structure is simplified, and the implementation has great effects.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram of an embodiment of the present invention, Fig. 2 is a side view of an embodiment of a spill prevention device, Fig. 3 is a sectional view of an embodiment of a spill preventer, and Figs. 4 and 5 are spill prevention devices. Explanatory diagram of the operation of the device, No. 6
The figure is a schematic diagram showing an example of a conventional contact tank, and FIG. 7 is a side view of its outflow prevention part. 1: Contact tank, 3: Biological filter bed, 4: Furnace material, 5a: Pipe, 6
: Outflow pipe of treated water, 7: Inflow pipe of backwash water, 11: Outflow prevention device, 15: Outflow preventer, 1B: Frame, IL 1
1 net, 20.21: Washing ball, 23 near o-to.

Claims (1)

[Claims] A biological filtration bed made of a filter material is provided inside, an inflow pipe for raw water and a discharge pipe for backwash water are provided at the top, and an outflow pipe for treated water and an inflow pipe for backwash water are provided at the bottom. In a raw water biological filtration system equipped with a contact tank, a pipe is provided above the contact tank that serves as an inflow pipe for raw water and a discharge pipe for backwash water, and an upper and lower Attaching at least one mesh having a mesh smaller than the diameter of the filter medium to a frame having an opening,
A spill preventer comprising a large number of cleaning balls having a diameter approximately equal to the diameter of the filter medium is connected to the net so as to be movable up and down, and when the water level in the contact tank rises, the spill preventer is activated. A contact tank for a biological filtration device, characterized in that it is equipped with a filter medium outflow prevention device that abuts the inlet of a pipe and forms a space between the two when the water level drops.