JP3375313B2 - Dewatering system, muddy water treatment system and dewatering method using the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a dehydration system for dehydrating a slurry so that it can be reused, a muddy water treatment system using the same, and a dehydration method.

[0002]

BACKGROUND OF THE INVENTION In the conventional mud water treatment system, after adding chemicals such as PAC and coagulant to the slurry, the slurry is dehydrated by using a filter press or the like to form a plastic dewatering cake. Was produced and the produced dehydrated cake was transported to a disposal site, a processing plant, etc. by a dump truck or the like.

As described above, when the slurry is made into a plastic dewatered cake, since it is in a plastic state, it is inevitable to use a belt conveyor for transportation, and it is inconvenient to handle, and the transportation facilities and the like are occupied on the ground. The area had become large.
Further, it took a dewatering time to change the liquid slurry into a plastic dewatering cake.

Considering the efficiency of muddy water treatment and the effect on the environment, it is desirable to reuse the slurry as much as possible. The so-called Waste Disposal Law stipulates that efforts should be made to reduce the amount of construction waste by suppressing it and recycling it.

In the case of reusing the slurry, it is possible to recycle it as fluidized soil without discarding the slurry as sludge by adding no chemicals and having a predetermined property. .

Here, the fluidized soil is mixed with adjusted mud or water to the soil generated by construction to impart fluidity, and a solidifying agent is added to the soil to stabilize it so that predetermined mechanical properties can be obtained. It was made.

Therefore, in particular, when the dehydrated cake is used for producing fluidized soil, it is necessary to uniformly impart appropriate fluidity to the soil generated from the construction, but such fluidity is physically imparted. It requires a lot of energy.

The present invention has been made in view of the above problems, and an object thereof is to dehydrate a slurry so that it can be reused, and particularly to dehydrate the slurry so that it can be reused as fluidized soil. A system, a muddy water treatment system using the system, and a dewatering method.

[0009]

In order to solve the above-mentioned problems, a dehydration system according to the present invention is in a state where a slurry is supplied and the dehydration chamber can be opened and closed, and the slurry is supplied to the dehydration chamber and sealed. And a pressurizing means for pressurizing the slurry with the pressurizing means to generate a semi-dehydrated cake in which the outer side of the slurry is dehydrated and the inner side is non-dehydrated. To do.

According to the present invention, the slurry can be made into a semi-dehydrated cake in which the outside is dehydrated and the inside is non-dehydrated. Since the outside of the cake is in a dehydrated state, that is, it has a plastic shape, it has good peelability from the dehydration chamber and can shorten the dehydration cycle. Further, since the inside of the cake is in a non-dehydrated state, the semi-dehydrated cake can be easily made into a liquid state by dropping or stirring the semi-dehydrated cake. This allows
Easy to transport and recycle.

The term "slurry" as used herein means a liquid in which water and fine particles are mixed, and in particular means muddy water after coarse particles having a particle size of 75 μm or more have been separated by a primary treatment facility or the like.

Further, since it is not necessary to make the slurry into a completely plastic body, the pressing time of the pressing means can be shortened and the dehydration cycle can be shortened. In addition, there is no need to add a chemical to the slurry, and when the slurry is reused as a raw material of fluidized soil, it can be reused as a stable raw material of fluidized soil for a long period of time.

Here, the term "recycle" means to effectively utilize useful materials or wastes obtained from wastes.

Further, the dehydrated state means a state in which the cake is dehydrated up to the performance limit of the pressurized dehydrating means, more specifically, a state in which the specific gravity of the cake (strictly speaking, the apparent specific gravity) is 1.6 or more, That is, it means a plastic state that does not exhibit a mud shape. Therefore, the cake in the dehydrated state exhibits remarkable plasticity.

The non-dehydrated state means a state in which the cake is not dehydrated up to the performance limit of the pressurized dehydrating means, and more specifically, a state in which the specific gravity of the cake is 1.3 to 1.4, that is, , Means a state of exhibiting a muddy state. Therefore, the non-dehydrated cake has an intermediate property between a viscous body and a plastic body.

Furthermore, the semi-dehydrated state means a state in which a dehydrated state and a non-dehydrated state are mixed.

Therefore, when the semi-dehydrated cake falls or is stirred, it becomes a concentrated slurry having a specific gravity of about 1.5. By ensuring a specific gravity of about 1.5, even when it is recycled as a raw material of fluidized soil, it can be recycled as a stable raw material of fluidized soil for a long period of time.

The term "fluidized soil" as used herein means that mixed mud water or water is mixed with construction-generated soil to give fluidity, and a solidifying agent is added to this so that predetermined mechanical properties can be obtained. Stabilized. The fluidized soil uses soil improvement technology that does not require compaction, and is used as a filling material for backfilling, backfilling, etc., as well as embankment material, roadbed material, and roadbed material.

Therefore, in particular, when the dehydrated cake is used for producing the fluidized soil, it is necessary to uniformly impart appropriate fluidity to the soil generated from the construction, but it is physically required to impart such fluidity. It requires a lot of energy.

According to the present invention, for example, by using a mud-like semi-dehydrated cake for producing fluidized soil,
The fluidity can be imparted with less energy as compared with the case of using the dehydrated cake, and the fluidized soil can be efficiently generated.

Further, it includes a suction means for sucking the water in the slurry from the outside of the dehydration chamber in a state where the slurry is pressurized, pressurizing using the pressurizing means, and sucking using the suctioning means. By doing so, it is preferable to generate a semi-dehydrated cake in which the outside of the slurry is in a dehydrated state and the inside is in a non-dehydrated state.

According to this, not only the slurry is pressurized, but also the water in the slurry is sucked from the outside of the dehydration chamber, so that the dehydration proceeds from the outside, so that the semi-dehydrated cake can be efficiently produced. it can. That is, by using the pressurizing means and the suction means in combination, a semi-dehydrated cake having desired properties can be obtained in a shorter time than in the case of using only the pressurizing means.

Further, it is preferable that a groove is formed in the dehydration chamber, and the suction means sucks the water in the slurry through the groove.

According to this, since the concave groove is formed, the contact area with the slurry is increased and the dehydration can be efficiently performed.

Further, it is preferable to include control means for controlling opening / closing of the dehydration chamber.

According to this, by automatically controlling the opening and closing of the dehydration chamber, it is possible to realize an efficient dehydration system without manpower.

Further, the slurry supply path includes at least one of a density meter and a flow meter, and the control means is
It is preferable that the dehydration chamber is changed from the closed and pressurized state to the open state based on the measurement result of at least one of the density meter and the flow meter.

According to this, by measuring the density (specific gravity) and the flow rate of the slurry, it is possible to adjust the time from the closed pressurized state to the open state of the dehydration chamber according to the property of the slurry, A semi-dehydrated cake having desired properties can be obtained regardless of the properties of the slurry.

Further, it includes a dehydration amount measuring means for measuring the dehydration amount from the dehydration chamber, and the control means changes the dehydration chamber from the closed pressurization state to the open state based on the measurement result of the dehydration amount measurement means. Preferably.

According to this, it is possible to quantitatively grasp the progress of dehydration by measuring the dehydration amount, and it is possible to easily determine whether or not the semi-dehydrated cake is in the state.

The dewatering chamber has a plurality of filter plates at least the inner side of which is covered with a filter cloth. The filter plates are provided with the concave grooves, and the filter plates are in close contact with each other. It is preferred to include a filter press machine in which the chamber is formed.

According to this, since dehydration can be carried out by filtration, fine particles are unlikely to be mixed in the filtrate, and dehydration can be carried out comfortably. In addition, the filtered water generated during dehydration can be reused by sending it to the mud making facility.

Further, according to this, since the groove is formed in the filter plate, the semi-dehydrated cake can be easily peeled from the filter plate. Further, the contact area between the slurry and the filter plate is increased by the concave groove, and the dehydration can be efficiently performed.

The suction means preferably includes a vacuum pump to suck the slurry under vacuum.

According to this, by using the vacuum pump, a negative pressure is generated and a force for drawing the water in the dehydration chamber to the outside is generated, so that dehydration can be performed more efficiently.

Further, it is preferable that the slurry is supplied from a primary treatment facility for discharged mud water.

According to this, the particle size is 75 in the primary treatment facility.
Since the coarse particles having a size of μm or more have been removed, the object to be dehydrated can be limited to the fine particles having a particle size of 74 μm or less, and the dehydration can be efficiently performed when dehydrating.

The muddy water treatment system according to the present invention,
The semi-dehydrated cake produced by the dewatering system is used to include a means for producing a backfill material or fluidized treated soil.

According to the present invention, using a semi-dehydrated cake,
The backfill material or fluidized soil can be generated, the slurry (semi-dehydrated cake) can be effectively used (recycled), and the amount of the slurry discarded as sludge can be reduced, thus reducing the amount of waste discharged. it can.

The backfill material is a mixture of water, cement, bentonite, sand and the like, and specifically, mortar, plastic injection material, chemical injection material, and the like. It is desired that the material used as the backfill material is one that hardens to have a natural strength or higher as soon as possible after injection and has a small volume shrinkage. The semi-dehydrated cake has a mud-like shape and is easily mixed with other materials, and because it is dehydrated, it has a predetermined strength and has a small volume shrinkage. Therefore, a good quality backfill material can be produced by using the semi-dehydrated cake.

When the fluidized soil is produced by using the semi-dewatered cake, the fluidized soil can be used as the above-mentioned construction soil or adjusted mud, which requires less energy than the case of using the dehydrated cake. Therefore, appropriate fluidity can be easily imparted.

As a means for producing the backfill material,
A general backfill material plant can be applied, and a general fluidized soil plant can also be applied as a means for generating fluidized soil.

Further, it includes a liquid cyclone device for concentrating the slurry and classifying it into a concentrated slurry and a non-concentrated slurry, and a concentrated slurry tank for storing the concentrated slurry,
It is preferable that the non-concentrated slurry is supplied to the dehydration system and the semi-dehydrated cake from the dehydration system is supplied to the concentrated slurry tank.

According to this, the semi-dewatered cake is mixed with the concentrated slurry from the liquid cyclone to form a concentrated slurry. By not adding a flocculant or the like to this concentrated slurry, the concentrated slurry can be reused as fluidized soil or the like.

On the other hand, the non-concentrated slurry (over mud water) classified by the liquid cyclone is usually treated as sludge and needs to be treated as waste, but the non-concentrated slurry is dehydrated into a semi-dehydrated cake to form a concentrated slurry. As a result, the non-concentrated slurry can be reused as fluidized soil. This makes it possible to reduce the amount of sludge that is waste.

The dewatering method according to the present invention is a dewatering method for making a slurry into a semi-dehydrated cake in which the outer side is dehydrated and the inner side is non-dehydrated. A pressurizing step of pressurizing the slurry in the dehydration chamber, determining whether the slurry is in a semi-dehydrated cake state, at the stage of the semi-dehydrated cake state, opening the dehydration chamber, the And a discharging step of discharging the semi-dehydrated cake.

According to the present invention, the slurry can be made into a semi-dehydrated cake in which the outside is dehydrated and the inside is non-dehydrated. Since the outside of the cake is in a dehydrated state, that is, it has a plastic shape, it has good peelability from the dehydration chamber and can shorten the dehydration cycle. Further, since the inside of the cake is in a non-dehydrated state, the semi-dehydrated cake can be easily made into a liquid state by dropping or stirring the semi-dehydrated cake. This allows
Easy to transport and recycle.

Here, the slurry means a liquid in which water and fine particles are mixed, and particularly means muddy water after coarse particles having a particle size of 75 μm or more are separated in a primary treatment facility or the like.

Further, since it is not necessary to make the slurry into a completely plastic body, the pressing time of the pressing means can be shortened and the dehydration cycle can be shortened. In addition, there is no need to add chemicals, and even when it is recycled as a raw material for fluidized soil, it can be reused as a stable backfill material or a raw material for fluidized soil over a long period of time.

[0050] Here, the term "recycle" means to effectively utilize useful materials or waste obtained from waste.

The dehydration state means a state in which the pressure dehydration means is dehydrated to the extent of its performance limit, and more specifically, a state in which the cake has a specific gravity (strictly, apparent specific gravity) of 1.6 or more, That is, it means a plastic state that does not exhibit a mud shape.

The non-dehydrated state means a state in which the pressure dehydration means has not been dehydrated up to the performance limit, more specifically, a state in which the specific gravity of the cake is 1.3 to 1.4, that is, , Means a state of exhibiting a muddy state.

Furthermore, the semi-dehydrated state means a state in which a dehydrated state and a non-dehydrated state are mixed.

Therefore, when the semi-dehydrated cake falls or is stirred, it becomes a concentrated slurry having a specific gravity of about 1.5. By ensuring a specific gravity of about 1.5, even when it is recycled as a raw material of fluidized soil, it can be recycled as a stable raw material of fluidized soil for a long period of time.

Further, it is preferable to include a suction step of sucking the water content of the slurry in the dehydration chamber from the outside of the dehydration chamber prior to the discharging process.

According to this, not only pressurization but also suction from the outside of the dehydration chamber can efficiently produce a semi-dehydrated cake. That is, by using the pressurizing means and the suction means in combination, a semi-dehydrated cake having desired properties can be obtained in a shorter time than in the case of using only the pressurizing means.

Here, when sucking from the outside of the dehydration chamber,
Vacuum suction is preferred.

According to this, by using a vacuum,
A negative pressure is generated, and a force for drawing the water in the dehydration chamber to the outside is generated, so that dehydration can be performed more efficiently.

Further, prior to the supplying step, there is a step of measuring at least one of the property and the flow rate of the slurry, and the discharging step is based on the measurement result of at least one of the property and the flow rate of the slurry. It is preferable to include a step of adjusting the time from the supply of the slurry to the opening of the dehydration chamber.

According to this, by measuring the property and flow rate of the slurry, it is possible to adjust the time from the closed pressurized state to the open state of the dehydration chamber according to the property of the slurry, and the property of the slurry. A semi-dehydrated cake having desired properties can be obtained regardless of the above.

Here, the properties of the slurry include, for example, specific gravity, density, viscosity and the like.

Further, there is a step of measuring the dehydration amount generated in the pressurizing step and the suction step, and the discharging step is a time period from the supply of the slurry to the opening of the dehydration chamber based on the dehydration amount. It is preferable to include a step of adjusting

According to this, by measuring the dehydration amount, it is possible to quantitatively grasp the progress of dehydration, and it is possible to easily determine whether or not the state of the semi-dehydrated cake has been reached.

Further, it is preferable to recycle the semi-dehydrated cake produced by the dehydration method as a backfill material or a raw material for fluidized soil.

According to this, the slurry (semi-dehydrated cake) can be effectively used by using it as the backfill material or the raw material of the fluidized soil, and the amount of discharged waste can be reduced.

[0066]

BEST MODE FOR CARRYING OUT THE INVENTION A case where the present invention is applied to a secondary treatment facility in a muddy water type shield construction method will be described below with reference to the drawings.

FIG. 1 is a plan view of secondary processing equipment according to an example of the present embodiment. Moreover, FIG. 2 is a side view of the secondary treatment facility according to an example of the present embodiment.

In the muddy water type shield construction method, the discharged mud water mixed with the excavated earth and sand excavated by the face is processed by the primary treatment facility.
The coarse particles of 5 μm or more are removed and supplied to the secondary treatment equipment.

In the secondary treatment equipment according to the present embodiment, the slurry (exhaust mud water) after the primary treatment is sent to the liquid cyclone 28 via the adjusting tank, and is classified and condensed at a predetermined classification point. The concentrated slurry (under muddy water) is sent to a concentrated slurry tank 30 provided below the liquid cyclone 28.

Here, the slurry means a liquid in which water and fine particles are mixed, and in this embodiment, in particular, coarse particles having a particle size of 75 μm or more (sand and gravel) are separated by the primary treatment equipment. Fine particles with a particle size of 74 μm or less (silt viscosity, etc.)
Means muddy water containing.

On the other hand, the non-concentrated mud water (over mud water) discharged from the liquid cyclone 28 is sent to the surplus mud water tank 32 through the pipe 25.

The slurry (exhaust mud water) sent to the surplus mud tank 32 is sent to the filter press device 50 to be dehydrated.

In the conventional filter press device, since the chemicals were added to the slurry before dehydration to dehydrate it, the dehydrated cake had to be handled as sludge and was a waste. In addition, since the dehydrated cake that was produced was discharged in a dehydrated state, it took a long time to dehydrate,
The belt conveyor had to be used to convey the dehydrated cake, and the area occupied above ground such as transportation equipment had become large.

In this embodiment, the dehydrated cake dehydrated by the filter press device 50 is sent to the concentrated slurry tank 30. After that, the concentrated slurry discharged from the concentrated slurry tank 30 is transported to a fluidization treatment plant or the like by a sludge transport dump truck or the like, and by being processed, it is reused as a raw material of fluidized soil or backfill material. It

That is, in the present embodiment, the dehydrated cake is not completely dehydrated, but is produced as a semi-dehydrated cake in which the outside is dehydrated and the inside is non-dehydrated.

The dehydrated state means a state in which the pressurized dehydration means is dehydrated to the extent of its performance limit, and more specifically, a state in which the cake has a specific gravity (strictly speaking, an apparent specific gravity) of 1.6 or more, That is, it means a plastic state that does not exhibit a mud shape.

The non-dehydrated state means a state in which the pressure dehydration means has not been dehydrated up to the performance limit, and more specifically, a state in which the specific gravity of the cake is 1.3 to 1.4, that is, , Means a state of exhibiting a muddy state.

The term “recycle” means to effectively utilize useful materials or wastes obtained from wastes.

The fluidized soil is prepared mud mixed with adjusted mud or water to impart fluidity, and a solidifying agent is added to the soil to stabilize the soil so that predetermined mechanical properties can be obtained. It is a thing. The fluidized soil uses soil improvement technology that does not require compaction, and is used as a filling material for backfilling, backfilling, etc., as well as embankment material, roadbed material, and roadbed material.

Therefore, in particular, when the dehydrated cake is used for producing the fluidized soil, it is necessary to uniformly impart appropriate fluidity to the soil generated from the construction, but it is physically required to impart such fluidity. It requires a lot of energy.

According to the present embodiment, for example, by using a semi-dehydrated cake in the form of mud for producing fluidized soil, it is possible to impart fluidity with less energy as compared with the case of using a dehydrated cake. Therefore, the fluidized soil can be efficiently generated.

The backfill material is a mixture of water, cement, bentonite, sand and the like, and specifically, mortar, plastic injection material, chemical injection material, and the like. It is desired that the material used as the backfill material is one that hardens to have a natural strength or higher as soon as possible after injection and has a small volume shrinkage. The semi-dehydrated cake has a mud-like shape and is easily mixed with other materials, and because it is dehydrated, it has a predetermined strength and has a small volume shrinkage. Therefore, a good quality backfill material can be produced by using the semi-dehydrated cake.

Next, the principle for producing this semi-dehydrated cake will be described.

FIG. 3 shows the filter plate 1 with the filter plate 16 in close contact with it.
It is a side surface sectional view of 6 parts.

Filter press 1 according to the present embodiment
The (filter press body) supplies the slurry to the inner filter chamber 17, and a plurality of filter plates 1 each covered with a filter cloth 18.
6 is crimped and pressurized by the secondary pump 4.

As a result, a positive pressure of 100 is applied to the slurry inside.
Is added. Further, by generating a negative pressure 102 inside the filter plate 16, the slurry inside the filter chamber 17 is pulled to the outside of the filter chamber 17. This produces a semi-dehydrated cake.

FIG. 4 is a schematic diagram of a semi-dehydrated cake.

The semi-dehydrated cake is a dehydrated cake 200 having a specific gravity of 1.6 or more on the outside and a non-dehydrated slurry having a specific gravity of 1.3 to 1.4 on the inside. Therefore, when the semi-dehydrated cake falls or is stirred, the specific gravity of 1.
It becomes a concentrated slurry of about 5. Since a specific gravity of about 1.5 is secured and no chemicals are added to the slurry or semi-dehydrated cake, it is a stable material for fluidized soil even when it is recycled as a material for fluidized soil, etc. Can be recycled as etc.

Further, since the outside of the semi-dehydrated cake is in a dehydrated state, that is, it is in a plastic state, it is easy to be separated from the filter chamber 17 and the dehydration cycle can be shortened. Further, the inside of the semi-dehydrated cake is in a non-dehydrated state, that is, because it is in a mud-like state, the semi-dehydrated cake can be easily made into a liquid state by dropping or stirring it. The semi-dehydrated cake can be transported more easily than when it is transported by a plastic material like a cake.

Next, the structure for producing such a semi-dehydrated cake will be described in detail.

As shown in FIGS. 1 and 2, the filter press device 50 includes a filter press 1 and an excess mud tank 32.
Between the filter press 1 and the primary pump 3 for supplying the slurry to the filter press 1 at low pressure, and between the excess mud tank 32 and the filter press 1, the slurry is supplied to the filter press 1 at high pressure. A secondary pump 4 to be supplied, a bypass block 5 for switching between the primary pump 3 and the secondary pump 4, and a vacuum pump 6 constituting a vacuum suction mechanism capable of vacuum sucking the slurry inside the filter chamber 17 of the filter press 1. It is configured to include.

The slurry in the surplus mud tank 32 is fed from the pressure feed unit including the primary pump 3 and the secondary pump 4 to the filter press 1
Is supplied to. In this example, the primary pump 3 is, for example, a centrifugal pump, and the secondary pump 4 is, for example, a plunger pump.

The primary pump 3 fills the filter press 1 with the slurry to be dehydrated, preferably at a mud feeding pressure of 98 to 196 kPa (1-2 kgf / cm ² ). The primary pump 3 can fill the filter chamber 17 of the filter press 1 with the slurry to be dehydrated in an extremely short time. Also,
The secondary pump 4 is for slurry, preferably 2940 kPa
Pressurize to a dehydration or filtration pressure of (30 kgf / cm ² ).

Filter press 1 with primary pump 3
By sending a large amount of mud in a short time, then closing the switching valve of the primary pump 3 and opening the switching valve of the secondary pump 4, it is possible to send the mud to the filter press 1 in one direction, that is, to prevent backflow. You can do it.

Next, the filter plate 16 will be described in detail.

FIG. 5 is a front view of the filter plate 16 portion.

The filter press 1 includes a plurality of filter plates 16 that are in close contact with each other, and the slurry supplied to the filter chamber 17 formed by adhering the adjacent filter plates 16 to each other is filtered with a filter cloth 18
A filter plate 19 is provided so that it can be dehydrated through. Each of the filter plates 16 has an arm 20 protruding left and right, which is supported by a rail 22 provided on a side frame 21 so as to be movable along the longitudinal direction of the device.

A slurry feeding hole 16 is provided at the center of the filter plate 16.
A has a plurality of recessed drainage grooves 16b formed in a ring shape with different diameters while being penetrated. Further, it has a vacuum suction port 16c leading to each drainage groove 16b,
The vacuum suction port 16c is connected to the vacuum collecting pipe 7 described above.

Wire mesh, punching metal, etc. are interposed between the filter plate 16 and the filter cloth 18, and a through hole is also formed in the center of these members.

In this embodiment, when the filter plate 19 is opened,
An opening frame device 10 for opening the frame in units of a plurality of filter plates 16 is provided. In particular, the frame opening device 10 has a connecting portion 23 attached to the tip of the arm 20 of each filter plate 16, and, for example, three adjacent filter plates 16 are connected by this connecting portion 28. The filter plates 16 are adapted to be continuously opened simultaneously.

When the filter plate 19 is closed, the filter plates 16 are in close contact with each other and are sealed with packing or the like to form a filter chamber 17.

Pressurization is performed in this manner. Next, a vacuum suction portion for generating a negative pressure will be described.

FIG. 6 is a schematic view of a vacuum suction portion.

The vacuum suction portion sucks the filtered water discharged from the filter press 1, and connects the vacuum collecting pipe 7 connected to each filter plate 16 of the filter press 1 and the separate tank 8 having the drainage pump 9 built therein. It is configured to include. In addition, the vacuum suction mechanism is operated by the vacuum pump 6 via the vacuum collecting pipe 7.

Next, the flow of the slurry using each of the above parts will be described.

FIG. 7 is a schematic diagram showing the flow of slurry in the secondary treatment facility.

First, the liquid cyclone 28 is adjusted from the adjusting tank 26.
Is supplied with slurry. In the liquid cyclone 28, classification is performed at a predetermined classification point by the centrifugal separation effect. In the liquid cyclone 28, an apex valve capable of automatically adjusting the throttle opening is provided at the discharge port of the under muddy water to concentrate the slurry.

The concentrated slurry (under muddy water) is sent to the concentrated slurry tank 30.

On the other hand, the non-concentrated muddy water (over muddy water) is sent to the surplus muddy water tank 32.

The slurry is sent from the excess mud water tank 32 to the filter press device 50, but when the amount of non-concentrated mud water supplied is large, the mud water is circulated from the excess mud water tank 32 to the adjusting tank 26.

The flow path from the surplus mud tank 32 to the filter press device 50 has a density meter 40 and a flow meter 42.
Is provided.

The specific gravity of the slurry is calculated from the density measured by the density meter 40, and the flow rate of the slurry is calculated by the flow meter 42. These measurement results are sent to the control device 60, and the control device 60 controls the filter press device 50.
Is controlled, and the opening and closing of the filter plate 19 is controlled.

That is, the opening and closing of the filter plate 19 is controlled at an optimum time for producing the above-mentioned semi-dehydrated cake.

According to this, by measuring the properties such as the specific gravity of the slurry and the flow rate, it is possible to adjust the time from the closed and pressurized state to the open state of the filter chamber 17 in accordance with the properties of the slurry. Optimal dehydration can be performed regardless of the properties of the slurry.

Next, the flow of the slurry in the filter press device 50 will be described.

When the slurry is supplied to the filter press 1, first, the primary pump 3 supplies the slurry at a relatively low pressure.
In this case, the filter board 19 is closed. By closing the filter plate 19 with a closed frame, the filter chambers 17 are formed by the adjacent filter plates 16 that are in close contact with each other. Further, a flow path to the surplus muddy water tank 32, the primary pump 3, and the filter press 1 is formed via the bypass block 5. The primary pump 3 fills the filter chamber 17 of the filter press 1 with the slurry to be dehydrated in an extremely short time.

Next, the switching valve 11 and the like are operated to form a flow path to the surplus mud water tank 32, the secondary pump 4, and the filter press 1 via the bypass block 5. The secondary pump 4 drives the slurry at a high pressure and raises it to a predetermined pressure (about 2940 kPa). By using the primary pump 3 and the secondary pump 4 as described above, high dehydration efficiency can be obtained by rapidly filling the slurry with the primary pump 3 and increasing the pressure with the secondary pump 4.

The filtered water separated during the dehydration is sucked into the separate tank 8 and drained to the filtered water tank 34. Further, a drainage meter 44 is provided in the flow path from the separate tank 8 to the drainage tank 34. The filtered water meter 44 is specifically a weir type water meter, and the measurement result of the filtered water quantity is transmitted to the control device 60. The control device 60 controls opening / closing of the filter board 19 based on the amount of filtered water.

It is possible to perform control based on the properties and flow rate of the slurry supplied to the above-mentioned filter press device 50, or control based on the amount of drainage water. The filter plate 19 can be opened and closed at the optimum timing for producing the dehydrated cake.

As described above, the semi-dehydrated cake is formed in the filter chamber 17. In this dehydration process, the vacuum suction mechanism is operated by the vacuum pump 6 via the vacuum collecting pipe 7. That is, the vacuum suction mechanism vacuum-sucks the water content of the slurry from the vacuum suction port 16c through the vacuum space formed by the drainage groove 16b of the filter plate 16. The vacuum suction causes the filter cloth 18 of the filter plate 16 to undergo a capillary phenomenon. In this way, dehydration efficiency can be further improved by using vacuum suction together.

Further, when the slurry is supplied to the filter press 1, the slurry is supplied at a relatively low pressure by the primary pump to fill the filter chamber, and the secondary pump is switched to increase the filtration pressure. In this way, two of the primary pump and the secondary pump
By supplying the slurry in stages, extremely high dehydration efficiency can be obtained. In this case, the dewatering efficiency can be further improved by sucking the filter chamber 17 by the vacuum suction mechanism, that is, by using the vacuum suction together.

Even when the slurry is sent to the filter press 1 by the primary pump 3, the water flows through the filter cloth 18 and the pipe to the vacuum collecting pipe 7. The normal mud pressure of the primary pump is 490 kPa (5 kgf / c
m ² ), but in the present embodiment, in order to suppress unnecessary leak and load on the primary pump 3, 98 to 196
When the pressure rises to kPa, the high pressure secondary pump 5 is switched to.

After dehydration, the filter plate 19 is opened by the frame opening device 10. In this embodiment, the three filter plates 16 are continuously and simultaneously opened to open the frame, whereby a large number of filter plates 16 are quickly and accurately opened, and the semi-dehydrated cakes are separated from between the separated filter plates 16. Falls. Further, in particular, when the filter frame 19 is opened by the frame opening device 10, the suction operation by the frame opening device 10 is stopped immediately before the frame opening. That is, the filter chamber 17 is opened to the atmospheric pressure, and air (atmospheric pressure) is sent to the filter chamber 17, whereby the filter plate 19 is easily opened.

By sending the atmosphere in this way, the filter cloth 18 vibrates and the peeling of the semi-dehydrated cake is promoted.

The fallen semi-dehydrated cake is shown in FIG. 1 and FIG.
The chute 24 shown in FIG.

In the case of a completely dehydrated plastic dehydrated cake, a belt conveyor is inevitably used instead of the chute 24, and the area required for transporting the dehydrated cake becomes large. By discharging the liquid semi-dehydrated cake as in the present embodiment, the chute 24 can be used for transportation, so that the area of transportation equipment can be saved and energy can be reduced by not using power means. .

The semi-dewatered cake put in the concentrated slurry tank 30 is mixed with the concentrated slurry from the liquid cyclone 28 and stirred by the stirring blades inside the concentrated slurry tank 30 to have a specific gravity of about 1.5 to 1.6. It becomes a concentrated slurry with a substantially uniform specific gravity.

When the concentrated slurry having a substantially uniform specific gravity in the concentrated slurry tank 30 is used as a material for fluidized soil, for example, it is used as a material for fluidized soil in a plant for processing the same ground equipment. It In addition, it is also possible to transport the concentrated slurry to a waste intermediate treatment site by a sludge transport dump truck or the like, perform intermediate treatment, and recycle it for purposes other than the raw material of the fluidized soil.

In this embodiment, since the semi-dehydrated cake is discharged to dehydrate without adding a chemical, a concentrated slurry which can be easily recycled as a raw material for fluidized soil can be produced.

The specific gravity of the concentrated slurry to be discharged is 1.
Since it has 5 or more, the volume is reduced as compared with the case where a concentrated slurry having a specific gravity of about 1.4 is carried, so that the carrying cost can be reduced.

Further, in the present embodiment, the dehydration process can be carried out in an extremely short time by using the primary pump 3 and the secondary pump 4 and by additionally using a vacuum. Moreover, since the dehydration is performed in a semi-dehydrated state, the dehydration cycle is shortened, and the apparatus can be configured substantially compact while ensuring a large processing capacity.

Next, the result of an experiment using the above-mentioned filter press 1 by the applicant will be described.

FIG. 8 is a graph showing the relationship between the dehydration time and the total amount of drainage in an experiment using the filter press 1 according to the example of the present embodiment.

As shown in FIG. 8, when the driving pressure of the filter press 1 is high, the total amount of drainage increases more than when the driving pressure is low. In addition, under the same pressure, negative pressure (here, 767 Pa (590 m
When the negative pressure of mHg) is present, the total amount of drainage increases more than when there is no negative pressure.

FIG. 9 is a graph showing the relationship between the dehydration time and the specific gravity of the entire semi-dehydrated cake in an experiment using the filter press 1 according to the example of the present embodiment.

As shown in FIG. 9, in order to obtain the desired cake specific gravity, it is more effective to use the negative pressure than to increase the pressing force.

Next, the results of experiments conducted by distinguishing the outside and inside of the semi-dehydrated cake will be described.

FIG. 10 is a graph showing the relationship between the dehydration time and the water content of each of the outer side and the inner side of the semi-dehydrated cake in the experiment using the filter press 1 according to the example of the present embodiment. FIG. 11 is a graph showing the relationship between the dehydration time and the specific gravities of the outer side and the inner side of the dehydrated cake, which are obtained by an experiment using the filter press 1 according to the example of the present embodiment.

As shown in FIG. 10 and FIG. 11, even if there is no negative pressure, the dehydration time is 15 minutes, the outside has a plasticity with a specific gravity of 1.5 or more, and the inside has a liquid-like semi-concentration of less than 1.4. Can produce dehydrated cake.

Further, when the negative pressure is applied, the semi-dehydrated cake having desired properties can be produced in a shorter time than when the negative pressure is not applied.

When there is a negative pressure as shown in FIGS. 10 and 11, the muddy water specific gravity is 1.13 and the true specific gravity is 2.658.
The results measured under conditions of a driving pressure of 2940 kPa and a negative pressure of 767 Pa are shown. In addition, in the case where there is no negative pressure shown in FIGS. 10 and 11, the measurement results are shown under the conditions that the muddy water specific gravity is 1.12, the true specific gravity is 2.658, and the driving pressure is 2940 kPa.

At the time of measurement, the unit of pressure is kg.
Since f / cm ² was used, the notation in the figure is kgf / c
It remains m ² .

Although the preferred embodiments to which the present invention is applied have been described above, the application of the present invention is not limited to the above-described embodiments, but can be applied to various modifications. For example, in the above-mentioned embodiment, the case of applying it to the muddy water type shield construction method has been described as an example, but the dehydration system according to the present invention is also used for dehydration of a construction engineer caused by construction work such as underground development, and dredging. It can also be applied to the dewatering process of bottom mud and the dewatering process of factories that generate waste liquid containing fine particles.

Although the concentrated slurry is used as the raw material for the fluidized soil in the above-mentioned embodiments, it may be used as the raw material for the backfill material.

According to this, the trouble of carrying the concentrated slurry and the like can be saved, and the concentrated slurry and the semi-dehydrated cake can be effectively used. Especially when constructing a tunnel using a shield machine etc., a large amount of backfill material is used,
By producing the backfill material using a semi-dehydrated cake,
The discharge amount of the slurry can be reduced, and at the same time, the supply amount of the material of the backfill material can be reduced, and the tunnel can be efficiently constructed.

Further, in the above-described embodiment, the concentrated slurry discharged from the concentrated slurry tank 30 is carried to a fluidization treatment plant or the like by a sludge transportation dump truck or the like, and is treated to be fluidized soil or back soil. Although it has been described that the material is recycled as a raw material for the filling material, a fluidized soil plant, a backfilling material plant, or the like may be provided in the above-ground facility where the filter press 1 is provided.

Further, the specific numerical values and the like described in the above embodiments do not limit the scope of the present invention and can be appropriately changed as necessary. The unit of the filter plate 16 opened by the frame opening device 10 is not limited to three units, and may be a unit larger or smaller than that.
Further, since the drainage groove that creates a vacuum state is characterized by having a groove itself, it can be formed in various shapes as well as a ring shape having different diameters, and the filter plate is also limited to a circular shape. It is needless to say that the shape may be, for example, a rectangle or a polygon such as a triangle or more without being processed.

[Brief description of drawings]

FIG. 1 is a plan view of secondary processing equipment according to an example of the present embodiment.

FIG. 2 is a side view of secondary treatment equipment according to an example of the present embodiment.

FIG. 3 is a side sectional view of a filter plate portion in a state where the filter plates are in close contact with each other.

FIG. 4 is a schematic diagram of a semi-dehydrated cake.

FIG. 5 is a front view of a filter plate portion.

FIG. 6 is a schematic view of a vacuum suction portion.

FIG. 7 is a schematic diagram showing a flow of slurry in a secondary treatment facility.

FIG. 8 is a graph showing the relationship between the dehydration time and the total amount of drainage in an experiment using the filter press according to the example of the present embodiment.

FIG. 9 is a graph showing the relationship between the dehydration time and the specific gravity of the entire semi-dehydrated cake in an experiment using the filter press according to the example of the present embodiment.

FIG. 10 is a graph showing the relationship between the dehydration time and the water content of each of the outer side and the inner side of the semi-dehydrated cake, which is obtained by an experiment using the filter press according to the example of the present embodiment.

FIG. 11 is a graph showing the relationship between the dehydration time and the specific gravity of each of the outer side and the inner side of the dehydrated cake, which is obtained by an experiment using the filter press according to the example of the present embodiment.

[Explanation of symbols]

3 Primary pump 4 Secondary pump 6 vacuum pump 8 separate tanks 10 Opening frame device 11 Switching valve 16 filter plates Room 17 18 filter cloth 19 plate 28 Hydrocyclone 32 Surplus mud tank 40 Density meter 42 Flowmeter 50 Filter press machine

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masayoshi Yasumoto 1-7-1, Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd. (72) Inventor Konosuke Nakamura 1-7-1, Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd. (72) Inventor Yoshio Iwai 1-7-1, Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd. (72) In-house Yasuhiko Asai 1-1-7, Kyobashi, Chuo-ku, Tokyo Toda Construction Co., Ltd. (72) Inventor Naofumi Matsukuma 7-10-4 Nishigotanda, Shinagawa-ku, Tokyo Inside Tomec Co., Ltd. (72) Inventor Takahiro Sekiguchi 7-10-4 Nishigotanda, Shinagawa-ku, Tokyo Inside Tomec (72) Inventor Akio Uraya 3-39-1 Hazawa, Nerima-ku, Tokyo San-A Industry Co., Ltd. (56) Reference JP-A-11-57322 (JP, A) (58) Field (Int.Cl. ^7, DB name) E02F 7/00 C02F 11/12 B01D 25/12

Claims (12)

(57) [Claims] 1. A dehydration chamber which is supplied with a slurry and can be opened and closed, a pressurizing unit which pressurizes the slurry in a state where the slurry is supplied and sealed in the dehydration chamber, and a state where the slurry is pressurized. From the outside of the dehydration chamber
Anda suction means for sucking the water in the slurry, under pressure with said pressurizing means, suction with the suction means
A dehydration system, wherein a semi-dehydrated cake in which the outside of the slurry is in a dehydrated state and the inside is in a non-dehydrated state is produced by pulling . 2. The dehydration system according to claim 1 , wherein a groove is formed in the dewatering chamber, and the suction means sucks water in the slurry through the groove. 3. The dehydration system according to claim 1 , further comprising control means for controlling opening / closing of the dehydration chamber. 4. The slurry supply path according to claim 3 , wherein at least one of a density meter and a flow meter is included in the slurry supply path, and the control means is based on a measurement result of at least one of the density meter and the flow meter. A dehydration system in which the dehydration chamber is changed from a closed pressurization state to an open state. 5. The dehydration amount measuring means for measuring the dehydration amount from the dehydration chamber according to any one of claims 3 and 4 , wherein the control means performs the dehydration on the basis of a measurement result of the dehydration amount measuring means. A dehydration system that changes a chamber from a closed pressurized state to an open state. 6. The dehydration chamber according to claim 2 , wherein the dehydration chamber has a plurality of filter plates at least the inside of which is covered with a filter cloth, and the groove is formed in the filter plate. A dehydration system comprising a filter press device in which the filter plates are in close contact with each other to form the dehydration chamber. 7. In any of claims 1 to 6, wherein the suction means, dewatering system characterized by comprising a vacuum pump, vacuum suction of the slurry. 8. A mud water characterized by comprising means for producing a backfill material or fluidized treated soil using the semi-dehydrated cake produced by the dehydration system according to any one of claims 1 to 7. Processing system. 9. The liquid cyclone device according to claim 8 , which concentrates the slurry and classifies the slurry into a concentrated slurry and a non-concentrated slurry; and a concentrated slurry tank for storing the concentrated slurry, A mud water treatment system, characterized in that it is supplied to a dehydration system and the semi-dehydrated cake from the dehydration system is supplied to the concentrated slurry tank. 10. A dehydration method for making a slurry into a semi-dehydrated cake, wherein the slurry is dehydrated on the outside and non-dehydrated on the inside, and a step of supplying the slurry to a dehydration chamber, and a step of adding the slurry in the dehydration chamber The pressurizing step of pressing and the moisture in the slurry in the dehydration chamber are absorbed from the outside of the dehydration chamber.
A suction step of pulling, and determining whether the slurry is in the state of semi-dehydrated cake, at the stage of the state of the semi-dehydrated cake, the dehydration chamber is opened, the discharge step of discharging the semi-dehydrated cake And a dehydration method comprising: 11. The method according to claim 10 , further comprising a step of measuring at least one of a property and a flow rate of the slurry prior to the supplying step, and the discharging step measuring at least one of a property and a flow rate of the slurry. Based on the result, a step of adjusting the time from the supply of the slurry to the opening of the dehydration chamber is included. 12. The method according to claim 10 , further comprising a step of measuring a dehydration amount generated in the pressurizing step and the suction step, wherein the discharging step is based on the dehydration amount. A dehydration method comprising a step of adjusting a time from supply to opening of the dehydration chamber.