JPH05318189A - Pressurization type dehydrating device for sludge treatment and sludge treatment - Google Patents

Abstract

PURPOSE:To efficiently dehydrate sludge with simple constitution without generating the clogging of filter cloths, etc., by smoothing the sludge packed side surfaces of screens and setting the direction of the slits of the screens at the same direction as the direction of pressurization. CONSTITUTION:A prescribed amt. of the sludge 11 to be treated is packed into the screen cylinder 2 from a sludge supplying device in the state of closing a bottom screen 6 and thereafter, a pressurizing plate 4 of a piston type pressurizing device 3 is moved in an arrow direction A to pressurize and compress the sludge in the screen cylinder 2. A slurry separates from the compressed sludge and flows out through the slits 9 of the screens 7 on the side walls and the bottom screen 6. This slurry is discharged to the outside by a slurry discharging device. The sludge is dropped into a lower sludge discharge port by opening the bottom screen 6 when the pressurization by the pressurizing device 3 stops and the outflow of the slurry from the sludge ends. The dehydration treatment is thus completed. Then, the dehydration is efficiently execute without generating the clogging, etc., of the filter cloths, etc.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressurized dewatering device and its device for treating sludge such as lakes and marshes, river sludge, sludge from sewage treatment plants, and sludge discharged from the shield construction method. It relates to a sludge treatment method to be used.

[0002]

2. Description of the Related Art Sun-drying has been used as a method for dewatering sludge for a long time, but this method requires a large land area and is now unrealistic in terms of securing land. There is. In the sludge dehydration treatment technology that is currently being attempted, a chemical treatment is performed as a pre-dehydration step. This is intended to enable dehydration by treating sludge with a flocculant or the like.

Next, dehydration by mechanical force is attempted. The first is vacuum filtration, in which the sludge on the filter cloth on the surface of the rotating drum is dehydrated in a vacuum. The second is pressure filtration, in which pressure is intermittently applied with a diaphragm in a filter frame and dehydrated through a filter cloth.

The third is dehydration by a centrifuge, which is due to specific gravity difference separation by centrifugal force of high speed rotation.

The fourth is granulation dehydration, in which sludge containing a polymer flocculant and water glass is drawn into a drum rotating at a slow speed to give a rotary motion to granulate into pellets.

[0006]

The ideal treatment technique for sludge is to perform a pre-chemical treatment such as coagulation of highly water-containing sludge which is difficult to dehydrate, typically sludge accumulated on lakes and river bottoms, By dehydration, it is regenerated as a low water content sludge to be usable as landfill soil or horticultural soil.

However, none of the above conventional sludge dewatering treatment methods is satisfactory.

That is, the method using vacuum filtration requires a large-scale apparatus, and its dehydration capacity and throughput are small. In addition, this method has a big drawback that the filter cloth is immediately clogged. Although the pressure filtration method is superior in dehydration ability to the vacuum filtration method,
It has the same drawbacks as the vacuum filtration method in that the apparatus becomes large-scale and the filter cloth is easily clogged. Further, the dewatering method using a centrifuge has a drawback that it has little effect on sludge that is difficult to separate such as sludge, and that the apparatus is expensive. Further, the granulation dehydration method is used because the apparatus has a simple structure and few failures, but the water content of the cake is not so good and it cannot be applied to all kinds of sludge including sludge.

[0009] As described above, the conventional sludge dewatering methods have various problems and no satisfactory solution has been found. Therefore, the basic treatment of sludge is given up, and a solidifying agent is added to sludge at the bottom of lakes and rivers. The current situation is that even simple treatment methods such as leaving it alone are being adopted. If satisfactory dehydration technology is not developed in sludge treatment, sludge problems may develop into major social problems.

Therefore, an object of the present invention is to eliminate the drawbacks of the above-mentioned conventional sludge dewatering treatment methods, and to efficiently perform sludge dewatering with a relatively simple structure without causing clogging of the filter cloth. An object of the present invention is to provide a sludge treatment device and method capable of performing the above.

[0011]

As a result of repeated research and experiments for solving the above-mentioned problems, the present inventor has found that a screen such as a wedge wire screen having a continuous slit is formed into a cylindrical or square screen. When a cylinder is formed and this screen cylinder is filled with sludge and pressurized,
Surprisingly, when the sludge filling side surface of this screen is smooth and the screen is arranged so that the direction of the slit of this screen is the same as the direction of pressurization, it is unexpectedly separated from the slit continuously. The present invention has been reached by discovering that the serous water is released and that the sludge itself does not flow out from the slit.

That is, the pressure type dehydrator for sludge treatment of the present invention which achieves the above object, comprises a screen cylinder filled with the sludge to be treated, and a pressurizing means for pressurizing the sludge to be filled in the screen barrel. The sludge filling side surface of the screen forming the side wall of the screen cylinder is smooth, and the direction of the slit of the screen is the same as the direction of pressurization by the pressurizing means.

As the object of the pressure dehydration experiment, the sludge at the bottom of the river in the downstream of the big city where solid-liquid separation is most difficult was selected.
As a chemical treatment as a pretreatment for pressure dehydration, a flocculant was added to the sludge to form a gel.

As the dehydration method, the pressure type dehydration method was adopted, which is the simplest and can downsize the apparatus. A wedge wire screen with continuous slits without clogging was adopted as the element of the dehydrator.

A screen cylinder in which the smooth surface of the wedge wire screen is arranged inside is made, and the continuous slits are arranged so that the direction of pressing is the same as the direction of pressurization. Filled with sludge. As for the pressurization, when the initial pressure was lowered, good separation of the syneresis water was observed, and it was discovered that the syneresis water gradually disengaged by gradually increasing the pressurization pressure.

It is common knowledge that in order to separate and dehydrate the syneresis water from the sludge, it is necessary to use a member having a narrow mesh such as a filter cloth as seen in the above-mentioned conventional dehydrators. It is unconventional from the viewpoint of the prior art that it is possible to remove the syneresis water from the sludge from the slit of the screen using the screen, and yet to prevent the sludge itself from flowing out of the slit. Is totally unexpected.

It has been clarified by the following experiment that one of the keys to the successful pressure dehydration of sludge using a screen cylinder having a continuous slit is in the arrangement direction of the screen slit.

A gel cylinder which is arranged by arranging the slits of the screen of the screen cylinder in a direction orthogonal to the direction of pressurization and using the same size of screen cylinder having the same slit width as in the above experiment and which has been subjected to the same chemical treatment is used. The same pressurization method was also used. However, unlike the above experiment,
Much more sludge than the synergic water flowed out through the slit in the screen, and the desired dehydration of sludge was not seen. According to the above-mentioned two kinds of experiments, since the slit and the smooth wire are oriented in the same direction as the pressurizing direction on the inside of the screen cylinder, that is, the sludge contact surface, the slidable inside the screen cylinder and the sludge inside the screen cylinder are continuously performed. It was proved that the sludge's capsule was not ruptured by the movement of the water, that is, the syneresis water was continuously released without sludge formation.

A further experiment was carried out using a screen as the pressing plate of the pressing means and a screen on the screen cylinder bottom surface (pressure receiving surface) orthogonal to the pressing direction. The amount was much higher than the syneresis water that came out from the pressure surface of the screen cylinder and the screen of the pressure receiving surface. It is understood that this phenomenon is due to the fact that the sludge in the vicinity of the pressure surface and the pressure receiving surface is consolidated at the stage of initial pressurization and has a lower water permeability than the sludge in the vicinity of the side surface of the screen cylinder. That is, when the water content of the sludge that had been consolidated after the pressure dehydration experiment was compared between those near the pressure surface and pressure receiving surface and those near the side surface, the water content of the pressure surface and near the pressure receiving surface was lower.

As described above, the separation efficiency of the syneresis water from the screen on the pressure surface and the pressure receiving surface of the screen cylinder is inferior to the separation efficiency of the separation water from the screen side surface, By disposing the screen also in the direction orthogonal to, the separation effect of the syneresis water can be enhanced as a whole as compared with the case where the pressure receiving surface is simply formed by the blind plate.

Next, when the distribution of the water content of the sludge after the pressure dehydration experiment was examined, it was found that the water content was lower as it was closer to the screen of the screen cylinder and higher as it was farther from the screen. Therefore, an experiment was conducted by shortening the distance between the sludge and the screen by using a combination of another screen cylinder in the screen cylinder and a combination of partition screen plates. Thus, a good dehydrating effect was obtained.

Therefore, in one aspect of the present invention, in addition to the configuration of the present invention, the pressure-type dehydrator has a structure in which a surface which is disposed inside the screen cylinder at a distance from the screen cylinder and which contacts the sludge to be treated is closed. It is characterized in that the sludge to be treated is filled in the space formed between the two screen cylinders.

Similarly, in one aspect of the present invention, in addition to the configuration of the present invention, the pressure type dehydrator has a pair of partition screens extending in the same direction as the pressure direction inside the screen cylinder. It is characterized in that they are provided at intervals from each other, and the nip portion of the space formed between these partition screens is closed.

The smaller the width of the slit of the screen, the safer the separated water can be separated. That is, the adjustment of the initial pressure is good, and even if the chemical treatment is insufficient, there is a high possibility of success. However, such a safe small slit design sacrifices the dewatering effect of sludge, and also reduces workability.

In the experiment, the slit widths are 0.1, 0.2,
Although 0.3, 0.4 and 0.8 m / m were used, the optimum design requires selection of the optimum slit width that satisfies both high dehydration performance and high processing workability.

Further, in reality, the optimum slit width may change depending on the pressure technique or the chemical pretreatment technique. Furthermore, it was found by experiments that the sludge itself, which is the target object, has a large difference in properties depending on the collection place.
In other words, the sludge collected from the downstream of the big city had a coagulant amount of 30% larger than that collected from the middle of the big city, but the degree of gelation was low, and the initial pressure was considerably lower than the initial pressure. It took a long time to gradually increase the pressure.

It was also found that even if the sludge at the bottom of the river is compared with the slime-mixed mud discharged from the shield construction method of civil engineering, it is necessary to use a combination in which the degree of addition of the coagulant and the speed of pressurization are different.

Therefore, in the optimum design of the screen, the optimum slit and the dimension between the facing surfaces of the screen are taken into consideration in consideration of the target sludge, the efficiency of the chemical pretreatment, the initial pressurization and the gradually increasing pressurization and the elapsed time. It is necessary to decide.

However, in any case, the width of the screen slit must be smaller than the width of the screen wire. If the width of the slit is the same as or larger than the width of the wire, if the width of the slit is large enough to allow the sludge to flow out from the slit, or if the width of the slit is small enough to prevent the sludge from flowing out of the slit. This is because the width of the wire is so small that the wire is deformed without being able to withstand the applied pressure.

In addition, from the results of the experiments, it was found that in any case, a sufficient dehydrating effect could not be obtained unless the distance between the opposing screen surfaces in the screen cylinder was 300 mm or less.

As the pressurizing means used to pressurize the sludge,
For example, a pressure plate that contacts and pressurizes the sludge filled in the screen cylinder, and a piston rod connected to this,
A piston type pressurizing device having a driving means for reciprocally driving the piston rod can be used.

In one aspect of the present invention, the screen cylinder has a cylindrical shape, and a screw press device is used as the pressing means. A cylindrical screen may be used as the screw shaft of the screw press device.

Further, there is provided a cylindrical inner screen cylinder which is arranged inside the screen cylinder at a distance from the screen cylinder and whose surface contacting the sludge to be treated is closed, and a space formed between both screen cylinders. The screw of the screw press device can also be disposed in the.

A hopper is required to fill the screen cylinder of the pressure type dehydrator of the present invention with the gelled sludge which has been pre-chemically treated by adding a coagulant.

The shape of the hopper is generally a plate structure consisting of a tapered receiving port and a straight body for pre-filling, but the sludge to be filled is a viscous gel-like sludge. , It adheres to the plate portion of the hopper, and it is difficult to perform an ideal uniform filling because air is entrained during filling.

Therefore, in one aspect of the present invention, the pressure type dehydrator for sludge treatment further comprises a hopper arranged on the sludge supply side in addition to the above-mentioned construction, and a screen is attached to the side of the hopper which comes into contact with sludge. The slit direction of this screen is the same as the sludge supply direction.

According to this apparatus, the friction area with the hopper during the movement of the sludge is greatly reduced as compared with the plate hopper, and the sludge moves along the direction of the screen wire, so that the sludge can be smoothly filled. You can In addition, the air entrained during filling passes through the slits of the screen and is removed, so that the amount of air accumulated in the sludge after filling is small, and uniform filling can be performed.

According to the present invention, in the sludge treatment method of filling the screen cylinder with the sludge to be treated and depressurizing the sludge, the surface of the screen forming the side wall of the screen cylinder is smooth on the sludge filling side, and There is provided a sludge treatment method, characterized in that the sludge to be treated is filled in a screen cylinder in which the direction of the slits of the screen is the same as the direction of pressurization and is dehydrated by applying pressure.

The pressure may be applied not only from one direction but also from one direction and the opposite direction separately or simultaneously. Further, the pressure may be applied from multiple directions such as four directions.

[0040]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a perspective view showing the main part of one embodiment of the device of the present invention. The pressurized dehydrator 1 is filled with sludge to be treated such as sludge. A square tubular screen tube 2,
The piston type pressurizing device 3 constituting a pressurizing means for pressurizing the sludge filled in the screen cylinder.

The piston type pressurizing device 3 has a shape and dimensions to be fitted in the screen cylinder 2, and a pressurizing plate 4 for contacting and pressurizing the sludge filled in the screen cylinder 2 and connected thereto. It is composed of a piston rod 5 and a driving means (not shown) having a known structure for reciprocatingly driving the piston rod 5. The pressure plate 4 moves in the direction of arrow A in the figure and is filled in the screen cylinder 2. Pressurize and compress sludge. That is, the arrow A direction is the pressurizing direction.

The screen cylinder 2 is open at the upper side, and the bottom surface is arranged at a bottom screen 6 arranged in a direction orthogonal to the pressing direction A.
Is formed by. The side wall of the screen cylinder 2 is composed of a wedge wire screen 7 consisting of a wedge wire 8 and a support rod 10. By arranging the smooth surfaces of the wedge wires 8 toward the inside (sludge filling side), the sludge filling side surface of the screen is It is formed as a smooth surface as a whole. Further, the slits 9 between the wedge wires 8 of the wedge wire screen 7 (see the enlarged view of the screen portion of FIG. 2) are oriented in the same direction as the pressing direction A (that is, in FIG. 1, the slits 9 are in the vertical direction). The wedge wires 8 are arranged so as to extend to each other. Further, as is apparent from FIG. 2, the width W1 of the slit 9 is formed to be much smaller than the width W2 of the wire 8. The width of the slit 9 is determined to be the maximum width within the range in which the sludge itself does not flow out and only the syneresis water is separated and flows out, in consideration of the type of sludge to be treated, the degree of pretreatment, the pressurizing condition and the like.

The distance between the facing surfaces of the side wall of the screen cylinder 2 is designed to be within 300 mm.

The bottom screen 6 is also arranged with the smooth surface of the wedge wire screen facing the sludge contact surface side, and the slit width of the sludge itself does not flow out when the sludge is pressed, and only the separated water flows out. It is designed to have a width that does.

A sludge supply device (not shown) is provided above the screen cylinder 2, and below the screen cylinder 2 there are separated slits of the wedge wire screen 7 and the bottom screen 6 on the side wall of the screen cylinder 2. A syneresis water discharge device (not shown) is provided for collecting and discharging the serum water.

Further, the bottom screen 6 is configured to be slidable in the direction of arrow B by a bottom screen opening / closing device (not shown). When the sludge is dehydrated, the bottom screen 6 is opened to remove the dehydrated sludge downward. It is designed to be dropped into the sludge discharge port (not shown).

Next, the operation of the apparatus having the above configuration will be described. After the bottom screen 6 is closed, a predetermined amount of sludge 11 to be treated is charged into the screen cylinder 2 from the sludge supply device as shown in FIG. 3 (a), and then the piston type addition is performed as shown in FIG. 3 (b). The pressure plate 4 of the pressure device 3 is moved in the direction of arrow A to pressurize and compress the sludge in the screen cylinder 2. At this time, it is preferable that the pressure is initially low and gradually increased. The optimum pressing force and pressing time are determined in consideration of the type of sludge to be treated, pretreatment with a flocculant, and the like.

The syneresis water is separated from the compressed sludge, and the slits 9 and the bottom screen 6 of the side wall screen 7 are separated.
Through the slit of FIG. 3B as shown by arrow C in FIG. 3B, and is discharged to the outside by the syneresis water discharge device. When the pressurization by the pressurizing device 3 is stopped and the flow of the syneresis water from the sludge is completed, the bottom screen 6 is opened and the sludge is dropped to the sludge discharge port below to complete the dehydration process.

FIG. 4 schematically shows another embodiment of the pressurized dehydrator according to the present invention, which is the same as the embodiment of FIG. 1 except that the screen cylinder is a cylindrical screen cylinder 20. It is a composition. The bottom surface of the cylindrical screen cylinder 20 is formed by the bottom screen 21 as in the embodiment of FIG.

FIG. 5 schematically shows another embodiment of the apparatus of the present invention. The screen cylinder 30 has the same construction as that of the embodiment of FIG. 1, but the screen cylinder 30 is provided inside the screen cylinder 30. A screen cylinder 31 made up of another small square cylinder is arranged at intervals. The small screen cylinder 31 has a similar shape to the screen cylinder 30, and the top surface in contact with the sludge to be treated is closed by the screen 32.
Its bottom surface is open and is placed on the bottom screen 33 of the screen cylinder 30. Also screen cylinder 3
In the screen of the side wall of No. 1, wedge wires are arranged so that the smooth surface thereof is formed on the side (outside) in contact with sludge.

When dewatering sludge using this apparatus,
As shown in FIG. 6 (a), the sludge 34 is transferred to both screen cylinders 3
The space formed between 0 and 31 is filled, and the pressurizing plate 4 is moved in the direction of arrow A as shown in FIG. 6B to pressurize and compress the sludge 34. Then, the syneresis water is separated from the compressed sludge 34 and flows out in the direction of arrow C through the slit of the screen cylinder 30 and in the direction of arrow D through the slits of the side wall screen and the top screen of the screen cylinder 31. .. In this embodiment, the inner screen tube 3
By arranging 1, the distance (a) between the opposing screens is narrowed, and therefore, the water content of the sludge compressed during this time is reduced as compared with the case where the internal screen cylinder 31 is not present, so that the dehydration efficiency is improved. You can

FIG. 7 schematically shows another embodiment of the apparatus of the present invention. In this embodiment, a partition screen is provided inside a rectangular screen cylinder 50, but a pair of partition screens 5 extending in the same direction as the pressing direction is used.
1, 52 are provided back to back with a space therebetween, and the top of the space formed between the partition screens is closed by a top plate 53.

Dehydration of sludge using this device is performed by pressurizing and compressing the sludge 54 as shown in FIG. 8 by the pressurizing device 3 equipped with a pair of pressurizing plates 4A, 4B and piston rods 5A, 5B. A pair of partition screens 51, 52
Since a space is formed between the partition walls, the syneresis water flows out to the outside of the screen cylinder in the direction of arrow C and also flows into the space between the partition screens 51 and 52 in the direction of arrow F. Dehydration is promoted through this, and the dehydration efficiency can be further improved.

FIGS. 9 to 17 show still another embodiment of the apparatus of the present invention, in which a cylindrical screen cylinder is used as the screen cylinder and a screw press device is used as the pressing means. ..

FIG. 9 schematically shows the whole apparatus of this type of embodiment, in which a screen cylinder 6 is provided in a housing 60.
1 is arranged sideways. A screw 62 is arranged in the screen cylinder 61 so as to be rotated by a driving device (not shown) connected to a shaft 66 thereof. Sludge H
Is supplied from the hopper 63 and rotates the screw 62
Is sent in the direction of arrow A to be compressed and dehydrated. The syneresis water W that has flowed out through the slit of the screen cylinder 61 is discharged from the drainage port 64, while the compressed and dehydrated sludge is discharged from the sludge discharge port 65.

FIG. 10 is a schematic view showing the screen cylinder 61 and the screw 66 taken out.
The slits of the No. 1 screen are arranged in the same direction as the pressing direction A.

FIG. 11 shows another embodiment of the apparatus of the present invention, which also uses a screw press system as the pressing means, but uses a cylindrical screen 67 as the shaft of the screw 62. That is, the cylindrical screen 67 is connected to a rotation drive device, and the screw 62 is wound around and fixed to the cylindrical screen 67. When the cylindrical screen 67 is rotationally driven, the screw 62 also rotates at the same time. According to this embodiment, the syneresis water from the compressed sludge flows out not only from the screen cylinder 61 to the outside but also to the inside of the cylindrical screen 67, so that the dehydration efficiency is improved.

FIG. 12 shows still another embodiment of the apparatus according to the present invention, in which an inner cylindrical screen screen 68 is provided inside the outer screen cylinder 61 and is coaxial with the cylindrical inner screen cylinder 68. The end surface that comes into contact with the sludge to be treated is closed by the plate 69. Both screen cylinders 61,
The screw 62 is arranged in the space formed between 68.

In this embodiment, both screen cylinders 6
Both 1 and 68 are fixed, and the screw 62 rotates. Also in this embodiment, the syneresis water from the sludge flows out from the outer screen cylinder 61 to the outside and also flows into the inner screen cylinder 68, so that the dehydration efficiency is improved.

An example of a hopper for supplying sludge used in the apparatus of the present invention is shown in FIGS. In FIG. 13, a plate-shaped screen 71 is attached to the inner surface of the hopper 70 having the inclined surface 70a and the vertical surface 70b. The screen 71 is a wedge wire 72 as shown in FIG.
And the rod 73 are crossed together so that the smooth surface of the wedge wire is the sludge supply surface and the slit direction is the same as the sludge supply direction. In FIG. 13, the inclined surface 70a and the vertical surface 7 are illustrated for convenience of description.
Although 0b is shown for each two surfaces, it is actually provided for every four surfaces.

[0061]

[Modification] In the above embodiments, only the screen cylinders having a square cylinder shape and a cylindrical shape are shown, but the screen cylinders are not limited to this, and may be polygonal cylinders of a triangular cylinder and a pentagonal cylinder.

Although the bottom surface of the screen cylinder is formed by the bottom screen in the above embodiment, it may be formed by a simple blind plate.

The wire of the screen is not limited to a wedge wire, and may have any shape such as a triangular shape, a square shape, a pentagonal shape or the like as long as it has a sectional shape capable of providing a smooth surface. Moreover, the cross-sectional shape of the support rod is not particularly limited to a circle, a square, a triangle, or the like. Further, the screen is not limited to a combination of a wire and a rod, and the same effect can be achieved with a slit plate in which a large number of slits are formed in the plate.

Even when a space is formed between partition screens as in the embodiment of FIG. 7, the number of partition screens is not limited to one, but a plurality of pairs of partition screens may be used to form a plurality of spaces between partition screens. May be.

Further, the pressurizing means is not limited to the piston type pressurizing device and the screw press type pressurizing device, and any means can be used as long as it can pressurize and compress the sludge filled in the screen cylinder. be able to.

When the screw press type pressurizing device of FIGS. 9 to 12 is used, the screen cylinder is horizontally placed in the above embodiment, but it is needless to say that it may be vertically placed.

Further, although the embodiments shown in FIGS. 1 to 6 have been described as being placed vertically, it is also possible to use these in a horizontal orientation.

[0068]

As described above, according to the present invention, since the screen cylinder is filled with the sludge to be treated and dehydrated under pressure, there is no possibility of clogging, and the sludge is efficiently constructed with a simple structure. It is possible to perform dehydration, and it is possible to easily dehydrate even sludge, which has been difficult to dehydrate in the past.

By disposing another screen cylinder or a partition screen inside the screen cylinder so that the distance between the opposing screens is narrowed, the dehydration efficiency can be further improved.

[Brief description of drawings]

FIG. 1 is a perspective view showing an embodiment of the device of the present invention.

FIG. 2 is a partially enlarged view of the screen according to the embodiment.

FIG. 3 is a diagram schematically showing a sludge dewatering method according to the embodiment.

FIG. 4 is a perspective view showing another embodiment of the device of the present invention.

FIG. 5 is a perspective view showing another embodiment of the device of the present invention.

FIG. 6 is a diagram schematically showing a sludge dewatering method according to the embodiment.

FIG. 7 is a perspective view showing another embodiment of the device of the present invention.

FIG. 8 is a view schematically showing a sludge dewatering method according to the example.

FIG. 9 is a sectional view showing another embodiment of the device of the present invention.

FIG. 10 is a diagram schematically showing a main part of the embodiment.

FIG. 11 is a diagram schematically showing a main part of another embodiment of the device of the present invention.

FIG. 12 is a view schematically showing a main part of still another embodiment of the device of the present invention.

FIG. 13 is a perspective view showing an example of a hopper used in the device of the present invention.

FIG. 14 is a partially enlarged view of the hopper.

[Explanation of symbols]

 1 Pressurized dehydrator 2 Screen cylinder 3 Pressurizer 6 Bottom screen 9 Slit

Claims (15)

[Claims] 1. A sludge-filled surface of a screen, which comprises a screen cylinder filled with sludge to be treated and a pressurizing means for pressurizing the sludge to be filled into the screen barrel, and which forms a side wall of the screen barrel. Is smooth, and the direction of the slit of the screen is the same as the direction of pressurization by the pressurizing means. 2. The apparatus according to claim 1, wherein the screen cylinder further has a screen arranged in a direction orthogonal to the pressing direction. 3. The device according to claim 1, wherein the width of the slit of the screen is smaller than the width of the wire of the screen. 4. A screen cylinder is provided inside the screen cylinder with a distance from the screen cylinder, the screen cylinder being closed with a surface in contact with the sludge to be treated, the sludge to be treated being formed between the screen cylinders. The device according to any one of claims 1 to 3, characterized in that the filled space is filled. 5. A pair of partition screens extending in the same direction as the pressurizing direction are provided inside the screen tube with a space between each other, and a section of a space formed between these partition screens. The device according to any of claims 1 to 4, characterized in that is closed. 6. The apparatus according to claim 1, wherein the shortest distance between opposing screen surfaces in the screen cylinder is 300 mm or less. 7. The device according to claim 1, wherein the screen cylinder has a cylindrical shape, and the pressurizing means is a screw press device. 8. The device according to claim 7, wherein a cylindrical screen is used as a shaft of a screw of the screw press device. 9. An inner screen cylinder having a cylindrical shape is provided inside the screen cylinder with a distance from the screen cylinder and the surface contacting with the sludge to be treated is closed, and is formed between both screen cylinders. Device according to claim 7, characterized in that the screws of the screw press device are arranged in a space. 10. A sludge supply side is further provided with a hopper, a screen is attached to the side of the hopper that comes into contact with sludge, and the direction of the slit of this screen is the same as the sludge supply direction. Item 10. The device according to any one of Items 1 to 9. 11. A sludge treatment method of dewatering by filling a screen cylinder with sludge to be treated and pressurizing the sludge, wherein the screen cylinder of the pressure-type dehydrator for sludge treatment according to claim 1 is treated. A sludge treatment method, characterized in that sludge is filled and dehydrated by pressurizing. 12. The method according to claim 11, wherein the pressurization is performed in one direction and the opposite direction. 13. The method according to claim 12, wherein the pressurization is performed from multiple directions. 14. The method according to claim 11, wherein the pressurization is initially performed at a low pressure and then gradually increased.
The method according to any one of 3 above. 15. The method according to claim 11, wherein the sludge to be treated is subjected to a chemical treatment with a flocculant in advance before dehydration under pressure.