JPH07100467A - Method for removing grit in grit chamber and apparatus for it - Google Patents

Abstract

PURPOSE:To simplify relatively accompanied work and apparatus to be necessary in filtering the water in a grit chamber and in use for a grit collector in an apparatus wherein earth and sand settled on the bottom part of the grit chamber are pumped out with water by means of a sand lifting pump. CONSTITUTION:In a method for collecting a grit in a grit chamber using a grit collector 15 with a grit lifting pump 12 faced to the bottom part of the grit chamber 2, a mixture of earth and sand and water pumped out by means of the grit lifting pump 12 is separated into earth and sand and water and the separated water is fed into the grit collector 15 for reusing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sand removing method using a sand removing device having a sand pump installed in a sand basin of a sewage treatment facility, and a device therefor.

[0002]

2. Description of the Related Art In order to discharge the sediment deposited at the bottom of a sedimentation basin to the outside of the sedimentation basin, conventionally, there is a pump that pumps the sediment along with water by a sand pump.

[0003] Generally, since the pumping sand pump pumps water more easily than the sand, it is necessary to pump the accumulated sand smoothly.
It is preferable to supply water to the sand basin so as not to run out of water.

Particularly, in the case of a so-called jet pump in which the sand pump utilizes the siphon effect produced by the supply of high-pressure water, high-pressure water for driving which is 3 to 4 times the pumping amount is required.

In addition, when discharging the sediment that has widely settled at the bottom of the sedimentation basin, it is common to collect the sediment in a sand collecting pit and discharge it, and some of which collect water with water from a water supply nozzle. is there.

[0006] As described above, when the sediment deposited at the bottom of the sand basin is pumped out by the lift pump, it is necessary to use a certain amount of water.

[0007]

If industrial water or the like is used as such water, the cost will increase, so it is conceivable to use water from a sand basin or pump well.

[0008] However, in order to use the water of a sand basin or the like containing the earth and sand, it is necessary to filter the water and remove the earth and sand to obtain clean water.

Further, as the sand is left in the filtering device with the filtration of this water, it is necessary to treat the sand and the like, and the accompanying work and the device necessary for that are complicated.

The present invention has been made under such circumstances, and in the case where the sediment deposited at the bottom of a sand basin is pumped out together with water by a sand pump, the water in the sand basin or the like is filtered to remove sand. It is intended to simplify the accompanying work and the device necessary for using the device.

[0011]

In order to achieve this object, the invention according to claim 1 uses a sand removing device having a sand lifting pump facing the bottom of the sand basin to remove sand from the sand basin. 2. In the method of sand removal in a sand basin, the mixture of earth and sand pumped out by the sand pump is separated into sand and water, and the separated water is supplied to a sand removing device for reuse.

[0012]

According to the method for removing sand from a sand basin according to claim 1, it is necessary to remove the water content of the mixture of earth and sand, etc. pumped out by the sand pump for the purpose of carrying it out. On the contrary, the water removed by the originally necessary treatment is the foreign matter such as earth and sand removed, so that the water contains a small amount of foreign matter.

Therefore, the burden of separating foreign matters for obtaining the used water from the water separated in this way is small, and the accompanying work and apparatus required for making the water usable in the sand remover are relatively simple. Becomes

[0014]

Embodiments of the present invention will be described below with reference to the drawings.

This embodiment is applied to a rainwater sedimentation basin at a pumping station in a terminal treatment plant.
Is connected to the downstream side of the inflow port 3 via a gate 4, and to the downstream side of the rainwater sedimentation basin 2 is connected a pump well 6 having a rainwater pump 5.

The rainwater sedimentation basin 2 is for removing sediment in the sewage by controlling the flow velocity of the sewage, which is mainly rainwater.

The pump well 6 is for draining sewage such as rainwater from which sediment has been separated in the rainwater sedimentation basin 2 into the discharge conduit by the rainwater pump 5.

A front grader 7 is arranged between the gate 4 and the rainwater sand basin 2, and a rear grader 8 is arranged between the rainwater sand pit 2 and the pump well 6.

A sand collecting pit 11 is formed at the center of the bottom of the rainwater sedimentation basin 2, and a sand pump 12 is installed in the sand collecting pit 11.

The sand collecting pit 11 is for collecting sediments separated from rainwater in the rainwater sedimentation basin 2 and settled and deposited all over the bottom, and discharging the sediments to the outside of the rainwater sedimentation basin 2. Is.

Therefore, the sand collecting pit 11 is located in the rainwater settling basin 2.
Is the deepest part at the bottom, and the overall shape of the bottom is stepwise so that the surrounding bottom becomes deeper toward the sand collecting pit 11.

Further, in this embodiment, the sand lifting pump 12 installed in the sand collecting pit 11 generates a negative pressure by supplying high-pressure driving water, and this negative pressure sucks water mixed with earth and sand. A so-called jet pump having the structure shown in FIG. 2, for example. The structure and operation of the sand pump 12 will be described later.

A large number of water supply nozzles 13 are installed at the bottom of the rainwater sedimentation basin 2 so as to be oriented substantially in the direction of the sand collecting pit 11, and these water supply nozzles 13 constitute a sand collecting device described later. To do.

Next, the rainwater sand basin 2 constructed as described above
The sand removing device 15 for discharging the sediment deposited on the bottom of the rainwater to the outside of the rainwater sedimentation basin 2 will be described.

The sand removing device 15 of this embodiment is provided with the sand collecting pit 11 for collecting the sediment deposited widely on the bottom of the rainwater sedimentation basin 2.
It comprises a sand collecting device 16 for collecting sand and a sand pump 12 as a sand discharging device for carrying out and transferring the sand collected in the sand collecting pit 11.

In this embodiment, since both the sand collecting device 16 and the sand pump 12 as the sand discharging device operate with pressurized water, a single water supply circuit 21 is common to both of them. Is configured.

In the water supply circuit 21, reference numeral 22 denotes a water supply tank. The water supply tank 22 is supplied with industrial water 23 and can be supplied with water via a filter device 24.

Then, the water in the water supply tank 22 is pressurized by the pressure pump 25 and is supplied to the water supply nozzle 1 in the state of high pressure water.
3 and the sand pump 12 are supplied.

The high-pressure water supplied to the water supply nozzles 13 is ejected at high pressure from each water supply nozzle 13, and the sediment deposited on the bottom of the rainwater sedimentation basin 2 is moved to the sand collection pit 11 side to collect sand.

The water discharged from the water supply nozzle 13 collects sand as described above, but at the same time, the rainwater sedimentation basin 2 is replenished with water and the sediment pumped by the sand pump 12 is used. It also has the significance of increasing the water content and improving its fluidity.

The high-pressure water supplied to the sand pump 12 acts as driving water for the sand pump 12.

That is, as shown in FIG. 2, the sand lifting pump 12 is for generating a negative pressure by ejecting the high-pressure water H into the upper portion 27 of the suction pipe 26.

As a result, due to the negative pressure, the water S mixed with earth and sand can be sucked from the lower end of the suction pipe 26. As shown by an arrow A in the figure, by supplying air to the upper portion 27 that generates a negative pressure, it is possible to prevent cavitation from occurring here.

The earth and sand sucked from the lower end portion of the suction pipe 26 as described above has the high pressure water H in the upper portion 27 of the suction pipe 26.
It is mixed with and transferred to the discharge pipe 28.

As described above, when the sand lifting pump 12 is a so-called jet pump-type sand lifting pump, it usually requires 3 to 4 times as much high pressure water as the high pressure water for driving. The discharge pipe 28 is smoothly transferred due to a large increase in the water content of the discharged soil and the like.

The earth and sand thus drawn out is transferred to the sand settler 31 via the discharge pipe 28 of the sand pump 12.

The sand settler 31 separates the mixture of earth and sand transferred by the discharge pipe 28 into earth and sand and water by the internal filtration device 31a. Is equivalent to.

The earth and sand separated by the sand settler 31 are
It is transferred to the sand hopper 32 by the conveyor device 31b, and waits for delivery to the outside of the pump station.

On the other hand, the water separated by the sand settling separator 31 is relatively clean water because the sediment content is removed as described above. Further, in this embodiment, since a jet pump type sand pump is used and high-pressure water for driving the jet pump type sand is mixed therein, the amount of water is large and the water quality is better than the water in the pump well 6 and the like.

Therefore, in this embodiment, a reflux pipe 33 is provided between the sand separator 31 and the filter device 24.
Is provided, and the water separated by the sand settler 31 is supplied to the water supply tank 22 via the filter device 24.

As a result, most of the amount of water to be supplied to the water supply tank 22 can depend on the water separated by the sand settler 31, and the amount of new industrial water 23 to be supplied is reduced.

Since the water separated by the sand settler 31 is in a relatively clean state as described above, the water can be used in the sand remover 15 as compared with the case of using water in the pump well 6 or the like. The degree of filtration required is extremely light, and the work involved and the complexity of the equipment are minimal.

In this embodiment, the stagnant water pump 34 is installed in the pump well 6 so that the sewage in the pump well 6 can be supplied to the filter device 24. This is to ensure the water supply to the sand removing device 15 in the case of a trouble such as the blockage of the passage 33.

In the embodiment described above, the reflux pipe 33 is connected to the filter device 24. However, when the sedimentation separator 31 has good separation performance, the direct water supply tank 22 It is also possible to supply to.

Furthermore, in the above-mentioned embodiment, the sand pump 12 is a so-called jet pump, but it goes without saying that the present invention is not limited to this.

For example, as shown in FIG.
When a so-called submersible sand pump of electric type (specifically, a screw spiral submersible pump) is used as 2, the high-pressure water system for driving of the above-mentioned embodiment becomes unnecessary.

Therefore, the amount of water required for sand removal work is reduced, but at the same time, the water content of the mixture of earth and sand reaching the sand settler 31 via the discharge pipe 28 of the sand pump 12 is relatively high. Since the water quality of the water supplied from the return conduit 33 to the filter device 24 is somewhat inferior to that of the above-described embodiment, the water quality is better than that of the water in the pump well 6 and the like. The same effect can be achieved.

[0048]

As described above, according to the method for sand removal of a sand basin according to claim 1, the mixture of earth and sand pumped by the sand pump originally has a moisture content for carrying-out treatment. It is necessary to remove, and the water removed by the originally necessary treatment is, on the contrary, foreign matter such as earth and sand removed, so that the water contains a small amount of foreign matter.

Therefore, the burden of separating foreign matters for obtaining the used water from the water separated in this way is small, and the accompanying work and apparatus required for making the water usable in the sand remover are relatively simple. Becomes

[Brief description of drawings]

FIG. 1 is an overall schematic view of a sand removing device for a sand basin.

FIG. 2 is a sectional view of a sand pump.

FIG. 3 is a diagram illustrating a modification of the sand removing device for a sand basin.

[Explanation of symbols]

 2 Rainwater sand basin (sand basin) 12 Sand pump 13 Water supply nozzle 15 Sand remover 22 Water supply tank 25 Pressure pump (pump) 28 Discharge pipe 31 Sediment separator (sediment separator) 33 Reflux pipeline

Claims (5)

[Claims] 1. A method for sand removal of a sand basin using a sand removal device having a sand unloading pump facing the bottom of the sand basin, wherein the mixture of earth and sand pumped by the sand unloading pump is mixed with earth and water. A method for removing sand from a sand basin, which comprises separating the separated water into a sand removal device and reusing it. 2. A sand removal apparatus having a sand pump that faces the bottom of a sand basin, and a water tank for storing water used in the sand removal apparatus is provided, and a discharge pipe of the sand pump is used to separate sediment. Guide it to the equipment and separate it into soil and water,
A sand removing device for a sand basin, which is provided with a reflux pipe for supplying the separated water to the used water tank. 3. The sand removing apparatus for a sand basin according to claim 2, further comprising a pump for pumping the water in the used water tank to a required portion of the sand removing apparatus. 4. The sand remover for a sand basin according to claim 3, wherein water pumped from the pump is supplied to the sand unloading pump as driving water. 5. The sand removal apparatus for a sand basin according to claim 3, wherein a water supply nozzle for collecting sand is installed at the bottom of the sand basin, and water pumped from the pump is supplied to the water supply nozzle. Sand removal equipment for sand basins.