JPH01139192A - Biological filter - Google Patents

Abstract

PURPOSE:To automatically prevent the outflow of a filter medium contained in backwashing water to the outside by providing >=2 contact tanks in parallel, and connecting the upper parts with a pipeline. CONSTITUTION:When the biological filter bed 3 of one contact tank 1 is washed, the valve 11 of a backwashing water discharge pipe 10 provided at the upper part is closed, and the valve 11a of a backwashing water discharge pipe 10a of the other contact tank 1a is opened. Backwashing water is then introduced into the tank 1 from a backwashing water inlet pipe 8 provided at the lower part of the tank 1 to wash the biological filter bed 3 in the tank 1. When the water level in the tank 1 is raised due to washing, the backwashing water contg. a part of the floated filter medium 4 flows into the other tank 1a through the pipeline 12 connecting the upper parts of the tanks 1 and 1a. As the flow velocity decreases rapidly in this case, the filter medium 4a settles in the tank 1a, and only the backwashing water and impurities are discharged from the discharge pipe 10a provided at the upper part of the other tank 1a. The biological filter bed 4a of the other tank 1a is washed in the same way.

Description

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

[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 in a contact tank using a P material made of a large number of carriers with microorganisms attached, and raw water sprinkled from the top of the contact tank is passed through this biological filtration bed. The water is then brought into contact with microorganisms, and various impurities in the raw water are removed through biological reactions and temporary adsorption, and then taken out as treated water.

FIG. 3 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 filter bed 3 is made of a carrier made of a material whose specific gravity is the same as or slightly larger than that of water, and has microorganisms attached thereto. 5 is a sprinkling pipe for raw water provided at the top of contact tank 1, 6 is an outflow pipe for treated water provided at the bottom of contact tank 1, 7 is a valve, 8 is also an inflow pipe for backwash water, 9
1 is a valve, IO is a backwash water discharge pipe provided below the raw water sprinkler pipe 5, and 11 is a valve.

In the contact tank 1 configured as described above, the valve 9.
11 is closed and raw water is sprinkled into the contact tank 1 from the raw water sprinkling pipe 5, the raw water passes through the biological weekend 3 and is taken out as treated water from the outflow pipe 6.

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 various impurities in the raw water are removed by filtration and adsorption.

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 purpose, the valves 9 and 11 are opened, the valve 7 is closed, and backflow water is spouted from the backwash water inflow pipe 8 into the contact tank 1, causing the reactor material 4 of the biological weekend 3 to flow and be washed, while at the same time Oxygen is supplied to the tank, and the backflow water after cleaning is discharged to the outside from the discharge pipe IO.

[Problems to be Solved by the Invention] In the above-mentioned contact tank C, when the biological filter bed is backwashed and the backflow water is discharged from the discharge pipe 1O, the I furnace material 4 mixed into the backflow water is It also leaks out. In order to prevent such outflow of the furnace material 4, a screen or filter is provided at the outlet of the discharge pipe 10, but since microorganisms are sticky, the furnace material 4 may adhere to the screen or filter and cause eye damage. They form clogs that must be removed by cleaning from time to time. Furthermore, when a screen or filter is used, the outflowed furnace material 4 must be collected in one place and returned to the contact tank 1, which poses a problem of high equipment costs. Furthermore, if the spilled furnace material 4 is left as it is, it is necessary to periodically replenish the furnace material 4 with new material, which causes various problems such as an increase in running costs.

The present invention was made to solve the above-mentioned problems, and its object is to provide a biological filtration device having a contact tank that automatically prevents outflow of furnace material.

[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 a raw water sprinkling pipe and a valve on the top. In a biological filtration device equipped with a contact tank having a discharge pipe for backflow water, and an outflow pipe for treated water and an inflow pipe for backwash water each having a valve at the bottom thereof,
The present invention provides a biological filtration device in which two or more of the above-mentioned contact tanks are arranged in parallel and their upper parts are connected by a pipe.

[Operation] When cleaning the biological filtration bed of one contact tank, close the valve of the backwash water discharge pipe of the other contact tank, open the valve of the backwash water discharge pipe of the other contact tank, and start the backwash of one side. Backwash water is flowed from the water inlet pipe to wash the biological filter bed. When the water level in the contact tank rises due to cleaning, the backwash water containing some of the fluidized reactor material flows into the other contact tank through the pipe, but at this time, the flow rate rapidly decreases, causing the reactor material to Only the backwash water and impurities are discharged from the discharge pipe.

When cleaning the biological filtration bed of the other contact tank, the same operation as above may be performed for that contact tank.

[Example] FIG. 1 is a schematic diagram of an example of the present invention, and this example shows a case where two contact tanks are arranged in parallel.

In the figure, 1 and 1a are contact tanks with the same structure, 3.3a is a living room made up of a large number of reactor materials 4 and 4a, and 5.5a is a raw water sprinkler pipe installed above the contact tanks 1 and 1a. . 6.
6a is a treated water outlet pipe equipped with a valve 7.7a, 8,8
Reference character a is an inflow pipe for backwash water equipped with valves 9 and 9a, and both inflow pipes 8 and 8a are connected to a backwash water source via a pump P. 10°10a is valve 11. A backwash water discharge pipe 12 is provided above the biological filtration beds 3.3a of the contact tanks 1 and 1a, and 12 is provided above the biological filtration beds 3 and 3a.
This is a pipe line that connects both contact tanks 1 and 1a.

Next, the present invention configured as described above will be explained in detail.

(1) When performing water treatment Valve 9. 9as 11. Close lla and close valve 7.
When 7a is opened and water is sprinkled from the water pipes 5 and 5a into both contact tanks 1 and 1a, the raw water is filtered through the biological enrichment beds 3 and 3a, and the treated water flows from the mountain backs 6 and 6a. taken outside.

(2) When cleaning the biological filter bed with backwash water First, when cleaning the biological filter bed 3 of one of the contact tanks 1, close the valves 7.7a, 9a, and tt, and close the valves 9.7a, 9a, and tt. lla is opened and the pump P sends backwash water from the inflow pipe 8 to the contact tank 1 (see Fig. 1).

As a result, the biological material - Weekend 3 is washed, and the backwash water contains some P
The other contact 1 is removed from the pipe 12 in a state containing material 3 and impurities.
sent to file. At this time, the backwash water flows into the wide contact tank 1a from the narrow pipe line 12, so the flow rate decreases rapidly, and the P material 4 contained therein settles on the biological filter bed 3a, and the backwash water flows into the wide contact tank 1a. Only relatively light impurities contained therein are discharged from the discharge pipe 10a.

Next, when cleaning the biological filter bed 3a of the other contact tank 1a, the valves 7.7a, 9. lla and close valve 9a.
, 11 is opened and backwash water is sent from the inflow pipe 8a to the contact Wj 1a, the P material 4a contained in the backwash water settles on the biological i filter 3 of the other contact tank 1, as described above. However, only the backwash water and impurities are discharged from the discharge pipe 10.

FIG. 2 is a schematic diagram showing another embodiment of the present invention. In this embodiment, the backwash water discharge pipe 10. 1Oa is provided at a position communicating with the biological filter bed 3.3a of the contact tank 1.1a, and this configuration further promotes sedimentation of pH 4.4a. In this case, the discharge pipe 10. lOa
Since the flow rate of the backwash water discharged from the filter is extremely low, there is no risk that the P material 4.4a of the biological filter beds 3, 3a will flow out.

In each of the above embodiments, one pump P is used to send backwash water to both contact tanks 1 and 1a, so the capacity of the backwash water pump is smaller than the overall raw water treatment capacity. can be halved.

In the above description, the case where two contact tanks are installed in parallel is shown, but three or more contact tanks may be installed in parallel.

Furthermore, although a case has been shown in which backwash water is sent to both contact tanks by one pump by switching the valves of the inflow pipes, backwash water may be sent to both contact tanks by separate pumps.

[Effects of the Invention] As is clear from the above explanation, the present invention has two
By installing more than one contact tank in parallel and connecting the contact tanks with pipes, the P material contained in the backwash water is automatically prevented from flowing out to the outside, so the configuration is extremely simple. It does not require nets or filters, does not require maintenance, and has great effects when implemented, such as reducing equipment costs and maintenance costs.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram of an embodiment of the present invention, FIG. 2 is a schematic diagram of another embodiment, and FIG. 3 is a schematic diagram showing an example of a conventional contact tank. 1.1a: Contact tank, 3,3a: Biological filter bed, 4゜4a
: P material, 5.5a: Raw water sprinkler pipe, 5.6a: Treated water outflow pipe, 8, 8a: Backwash water inflow pipe, 10° 10a
: Backwash water discharge pipe, 12: Pipe line.

Claims (1)

[Claims] A biological filtration bed made of a filter material is provided inside, a backflow water discharge pipe equipped with a raw water sprinkling pipe and a valve at the upper part, and a treated water discharge pipe and a treated water discharge pipe each equipped with a valve at the lower part. A biological filtration device having a contact tank provided with an inflow pipe for backwash water, characterized in that two or more of the contact tanks are arranged side by side and their upper parts are connected by a pipe line.