JP6721493B2 - Screw conveyor type separator and wastewater treatment system - Google Patents

Description

The present invention relates to a screw conveyor type separation device and a wastewater treatment system.

Examples of methods conventionally used in so-called separation devices such as concentrators and dehydrators include a centrifuge method, a floating concentration method, and a screen concentration dehydration method. Also, sludge such as sewage or factory wastewater having a high water content as an object is put into a cylindrical casing, and a screw provided in this casing is rotated to squeeze and dehydrate while conveying the object. A screw conveyor type separator is used. For example, Patent Document 1 describes a device that rotates a screw provided with two screw blades to squeeze while conveying an object. This device forms a first region and a second region sandwiched by two screw blades inside a caging. This apparatus conveys the target object in the first area and discharges the target object from the discharge port of the target object. Further, this apparatus conveys the separation liquid generated by dehydration in the second area and discharges the separation liquid from the separation liquid discharge port.

International Publication No. 2015/186612

The device described in Patent Document 1 conveys the separated liquid in the second region in a state of being isolated from the target. Therefore, when the target is mixed in the second region, the target is mixed in the separated liquid. The device of Patent Document 1 is provided with a cover that covers the second region in order to prevent the object from entering the second region. This cover is provided so as to overlap with a charging port for charging an object into the device. Therefore, in this apparatus, the object thrown in from the throwing port is dammed by the cover to prevent the object from entering the second area.

However, an object such as sludge contains water and is slippery, and since the screw is rotating, the object may pass through the cover and enter the second region. As described above, in a device that rotates a screw provided with a plurality of screw blades and squeezes an object while conveying the object, there is room for improvement in terms of suppressing mixing of the object with the separated liquid.

The present invention is made in view of the above, and an object of the present invention is to provide a screw conveyor type separation device and a wastewater treatment system which suppress mixing of a target object into a separated liquid.

In order to solve the above-mentioned problems and achieve the object, the screw conveyor type separation device of the present disclosure squeezes an object input from an object input port, and presses the pressed object from the object output port. Discharge, a screw conveyor type separation device for discharging the separated liquid separated from the target by pressing from the separated liquid discharge port, the target discharge port is opened at one end, the other end The separated liquid discharge port is opened, in the intermediate portion between the one end portion and the other end portion, a cylindrical caging in which the object input port is opened, and provided inside the caging, From the first position between the screw shaft extending along the extending direction which is the direction from the one end to the other end, and the first position between the one end and the intermediate part, the intermediate part And a second position between the other end and a first screw blade spirally extending on the outer peripheral surface of the screw shaft, and from the intermediate position on the other end side of the intermediate part to the second position. To the other end side, the first screw blade extends spirally on the outer peripheral surface of the screw shaft so as to be spaced a predetermined distance from the first screw blade along the extending direction. Forming a first space between one of the two surfaces facing each other and the first screw blade facing the one surface, and facing the other surface of the two surfaces and the other surface. A second screw blade that forms a second space between the first screw blade and the first space, which is provided in the first space and is closer to the first space on the other end side than the position where the second space is provided. And a separation liquid partition wall portion for preventing the intrusion of the target object, and by the rotation of the screw shaft, separates the separation liquid by squeezing the target object input from the target object input port, the separation liquid Is moved in the first space and discharged from the separated liquid discharge port, and the compressed object is moved in the second space and discharged from the object discharge port.

In the screw conveyor type separation device, the separated liquid partition wall portion is in contact with the screw shaft, the first screw blade, and the second screw blade, and is provided at the one end side and the other side. Is preferably separated from the end side of the.

In the screw conveyor-type separation device, it is preferable that the caging is inclined such that the central axis moves downward in the vertical direction toward the other end.

It is preferable that the screw conveyor type separating device further includes an inclination adjusting unit that adjusts an inclination angle of the caging.

The screw conveyor type separation device is provided in the second space on the other end side of the separation liquid partition wall portion, and allows the object in the second space to flow out to the separation liquid discharge port. It is preferable to further include an object partition wall portion to be dammed.

In the screw conveyor type separation device, it is preferable that the separated liquid discharge port is provided vertically above the screw shaft.

In order to solve the above-mentioned problems and achieve the object, the wastewater treatment system of the present disclosure is a wastewater treatment system including a solid-liquid separation tank for separating sludge from organic wastewater, and the screw conveyor type separation device. The screw conveyor type separation device is configured to concentrate the sludge discharged from the solid-liquid separation tank, and to return the separated liquid generated during the concentration of the sludge to the solid-liquid separation tank. It is preferable.

In the wastewater treatment system, it is preferable that a screw conveyor type separation device is provided in the solid-liquid separation tank.

In order to solve the above-mentioned problems and achieve the object, the wastewater treatment system of the present disclosure includes a reaction tank that performs biological treatment on organic wastewater, and a solid-liquid separation tank that separates sludge from the organic wastewater. A wastewater treatment system comprising the screw conveyor type separation device, wherein the screw conveyor type separation device draws sludge from the reaction tank and concentrates it, and returns the concentrated sludge to the reaction tank. At the same time, it is preferable that the separated liquid generated when the sludge is concentrated can be supplied to the solid-liquid separation tank.

According to the present invention, it is possible to prevent the target liquid from being mixed into the separated liquid.

It is a partial cross section figure of the screw conveyor type separation device concerning this embodiment. It is a schematic diagram for demonstrating operation|movement of the screw conveyor type separator which concerns on this embodiment. It is a schematic diagram for demonstrating operation|movement of the screw conveyor type separator which concerns on this embodiment. It is a block diagram which shows a part of wastewater treatment system by a 1st Example. It is an approximate line figure showing the settling basin for explaining the modification of the 1st example. It is a block diagram which shows a part of wastewater treatment system by a 2nd Example.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings. The present invention is not limited to the embodiments described below.

(Structure of screw conveyor type separator)
The screw conveyor type separation device according to the present embodiment will be described. FIG. 1 is a partial cross-sectional view of the screw conveyor type separation device according to the present embodiment. As shown in FIG. 1, the screw conveyor type separation device 1 according to the present embodiment includes a caging 10, a screw shaft 12, a first screw blade 14, a second screw blade 16, a separation liquid partition wall portion 17, an object partition wall portion 18. , And an inclination adjusting unit 19. The screw conveyor type separation device 1 squeezes the target object A input from the target object input port 27 and discharges the compressed target object A from the target object discharge port 24. Then, the screw conveyor type separation device 1 discharges the separation liquid C separated from the object A by pressing from the separation liquid discharge port 26. The object A is sludge such as sewage or factory wastewater having a high water content. The object A is a flocculated solid material containing a liquid component. In the present embodiment, by using a device provided in the preceding stage of the screw conveyor type separating device 1, for example, a flocculant is added to the solid matter component by adding a flocculant, and the object A containing the liquid component in the solid matter is added. May be generated. In the screw conveyor type separation device 1, the target object A generated by this device is input from the target object input port 27. However, the flocculation of the solid component by this device is not limited to the addition of the coagulant.

The caging 10 is a tubular member that extends from one end 20 to the other end 22 along the extending direction E. Although the caging 10 is a cylindrical member, its one end 20 side is reduced in diameter. The extending direction E is the axial direction of the caging 10. The extending direction E inclines downward in the vertical direction Z with respect to the horizontal direction X as it extends toward the other end 22 side. That is, the caging 10 is inclined such that the central axis along the extending direction E moves (is located) toward the lower side in the vertical direction Z toward the other end 22.

The caging 10 has an object discharge port 24 opened at one end 20. The object discharge port 24 allows the screw shaft 12 to penetrate therethrough. In addition, the caging 10 has a separated liquid discharge port 26 opened at the other end 22. The separated liquid discharge port 26 is an opening different from the hole through which the screw shaft 12 passes, and is provided above the screw shaft 12 in the vertical direction Z. In addition, in the caging 10, the object insertion port 27 is opened in the intermediate portion 23. The intermediate portion 23 is a portion along the extending direction E between the one end 20 and the other end 22. The intermediate portion 23 is preferably located near the center of the caging 10 along the extending direction E. For example, the length along the extending direction E from the one end 20 to the intermediate portion 23 is preferably 40% or more and 60% or less with respect to the entire length of the caging 10 along the extending direction E. However, the position of the intermediate portion 23 is arbitrary as long as it is between the one end portion 20 and the other end portion 22, and for example, it is located closer to the one end portion 20 side than the center of the caging 10. Good. The target object inlet 27 opens at the outer periphery of the caging 10 at the position of the intermediate portion 23.

The screw shaft 12 has a columnar shape, is provided inside the caging 10, and extends along the extending direction E. The screw shaft 12 is provided inside the caging 10 so as to penetrate the caging 10 along the extending direction E. That is, the one end 30 of the screw shaft 12 is located on the one end 20 side of the caging 10 and projects from the one end 20 of the caging 10 to the outside of the caging 10. Similarly, the other end 32 of the screw shaft 12 is located on the other end 22 side of the caging 10, and projects from the other end 22 of the caging 10 to the outside of the caging 10. At least one of the one end 30 and the other end 32 of the screw shaft 12 is connected to a motor (none of which is shown) whose shaft is designated by a bearing. The screw shaft 12 is rotated in the direction R about the extending direction E as an axis center by this motor.

The first screw blade 14 is provided so as to spirally extend from the first position 34 to the second position 36 on the outer peripheral surface of the screw shaft 12. The first position 34 is the position of one end of the first screw blade 14, that is, the position where the winding of the first screw blade 14 is started. The first position 34 is a position between the one end portion 20 and the intermediate portion 23 of the caging 10. The second position 36 is the position of the other end of the first screw blade 14, that is, the position where the winding of the first screw blade 14 ends. The second position 36 is a position between the middle portion 23 of the caging 10 and the other end 22. That is, the first screw blade 14 is provided in the caging 10 so as to pass through the position where the object inlet 27 is provided.

The first screw blade 14 is wound from the second position 36 toward the first position 34 in the same direction as the direction R which is the rotation direction of the screw shaft 12. That is, when the rotation direction (direction R) of the screw shaft 12 is clockwise when the one end 30 is viewed from the other end 32, the first screw blade 14 has a so-called Z winding (right hand) spiral shape. It is provided (spiral shape). On the other hand, when the rotation direction (direction R) of the screw shaft 12 is counterclockwise when the one end 30 is seen from the other end 32, the first screw blade 14 has a so-called S winding (left hand). It is provided in a spiral shape. The first screw blade 14 rotates as the screw shaft 12 rotates.

The second screw blade 16 is provided so as to spirally extend from the intermediate position 40 toward the other end 32 side on the outer peripheral surface of the screw shaft 12. The second screw blade 16 is provided along the extending direction E at a position offset from the first screw blade 14 by a predetermined distance. The intermediate position 40 is the position of one end of the second screw blade 16, that is, the position where the winding of the second screw blade 16 starts. The intermediate position 40 is a position between the intermediate part 23 and the other end 22 of the caging 10, and is a position closer to the other end 22 than the intermediate part 23. Furthermore, the intermediate position 40 is located closer to the one end 20 than the second position 36 of the first screw blade 14. The intermediate position 40 is a position closer to the end portion 22 side than the middle portion 23 of the caging 10, but is preferably a position closer to the middle portion 23 than the other end portion 22.

More specifically, the second screw blade 16 is provided so as to spirally extend from the intermediate position 40 to the end position 42 on the outer peripheral surface of the screw shaft 12. The end position 42 is the position of the other end of the second screw blade 16, that is, the position where the winding of the second screw blade 16 ends. The end position 42 is a position between the intermediate position 40 and the other end 22 of the caging 10. That is, the second screw blade 16 does not pass through the position where the target object inlet 27 is provided in the caging 10. The second screw blade 16 is also wound in the same winding direction as the first screw blade 14. The second screw blade 16 also rotates as the screw shaft 12 rotates.

In this way, the first screw blade 14 is spirally provided on the outer peripheral surface of the screw shaft 12 from the first position 34 to the second position 36. The second screw blade 16 is helically provided on the outer peripheral surface of the screw shaft 12 from the intermediate position 40 to the end position 42 at a predetermined distance from the first screw blade 14. The intermediate position 40 (position at which winding starts) of the second screw blade 16 is located closer to the other end 22 side than the first position 34 (position at which winding starts) of the first screw blade 14. There is. The end position 42 (the position where the winding ends) of the second screw blade 16 is the same as the second position 36 (the position where the winding ends) of the first screw blade 14 along the extending direction E. It is in the position. However, the end position 42 and the second position 36 may be displaced along the extending direction E.

The screw conveyor type separation device 1 is different in the section in which the first screw blade 14 and the second screw blade 16 extend in this way. Therefore, the screw conveyor type separation device 1 extends along the extending direction E of the single screw section K1 from the first position 34 to the intermediate position 40 and the double screw section K2 from the intermediate position 40 to the end position 42. It can be said that it is divided into two sections. The single screw section K1 is a section of the first screw blade 14 and the second screw blade 16 in which only the first screw blade 14 is provided. The double screw section K2 is a section in which both the first screw blade 14 and the second screw blade 16 are provided. The single screw section K1 is a section on one end 20 side, that is, a section on which the target object discharge port 24 is provided, and an intermediate portion 23, that is, a target object input port 27 is provided in the section. There is. The double screw section K2 is a section adjacent to the other end 22 side of the single screw section K1, and is a section in which the target object inlet 27 is not provided.

In the single screw section K1, the first screw blades 14 form a charging space T0 between the first screw blades 14 adjacent to each other along the extending direction E. Further, here, the surface of the second screw blade 16 on the side of the one end 20 along the extending direction E is referred to as one surface 16a. The surface of the second screw blade 16 on the other end 22 side along the extending direction E is referred to as the other surface 16b. The two surfaces of the one surface 16a and the other surface 16b face the first screw blade 14 along the extending direction E, respectively. Specifically, the one surface 16a faces the first screw blade 14 on the one end 20 side. The other surface 16b faces the first screw blade 14 on the other end 22 side. In the double screw section K2, the second screw blade 16 forms a first space T1 between the one surface 16a and the first screw blade 14 facing the one surface 16a. In addition, the second screw blade 16 forms a second space T2 between the other surface 16b and the first screw blade 14 facing the other surface 16b in the double screw section K2.

The charging space T0 is a space communicating with the target charging port 27, and the target A is charged from the target charging port 27. The first space T1 is a space in which the separated liquid C is transported on the other end 22 side of the separated liquid partition wall portion 17 described later. The first space T1 is separated from the input space T0 by the separation liquid partition wall 17 on the other end 22 side of the separation liquid partition wall 17. The first space T1 is separated from the second space T2 by the first screw blade 14 and the second screw blade 16. The second space T2 is a space in which the object A is transported. The second space T2 communicates with the charging space T0.

Further, a slit H, which is a minute gap, is provided between the outer peripheral portion of the first screw blade 14 and the inner peripheral surface of the caging 10, and between the outer peripheral portion of the second screw blade 16 and the inner peripheral surface of the caging 10. Is configured to occur. The slit H, which is a minute gap, has a size such that it blocks the passage of the solid components of the flocculated object A and the compressed object A. That is, the slit H is set to be smaller than the diameter of the flocculated solid component. Further, liquid components such as the separated liquid C can pass through the slits H. The slit H is specifically a gap of, for example, about 1 to 2 mm. As a result, the charging space T0 and the first space T1 are in communication with each other in the area of the slit H, but are cut off from each other in the area other than the area of the slit H. Similarly, the first space T1 and the second space T2 are in communication with each other in the area of the slit H, but are cut off from each other in the area other than the area of the slit H.

Further, the outer peripheral portion of the first screw blade 14 and the outer peripheral portion of the second screw blade 16 are not provided with a cover that covers the first space T1 and the second space T2. That is, the inner peripheral surface of the caging 10 and the first space T1 are open. Similarly, the inner peripheral surface of the caging 10 and the second space T2 are open. Further, the space between the inner peripheral surface of the caging 10 and the charging space T0 is also open. The screw conveyor type separating apparatus 1 does not have such a cover, so that the solid component in the object A is prevented from being clogged on the inner peripheral surface of the caging 10, and the risk of the apparatus stopping due to clogging is reduced. It becomes possible.

The separated liquid partition wall portion 17 is a baffle that prevents the target A from entering the first space T1 on the other end 22 side of the installed position. The separated liquid partition wall portion 17 is provided in the first space T1 at an intermediate position 40 where the winding of the second screw blade 16 starts. The separated liquid partition 17 is in contact with the screw shaft 12, the first screw blade 14, and the second screw blade 16 at the intermediate position 40. Furthermore, the separated liquid partition 17 is arranged at the intermediate position 40 so as to overlap the region surrounded by the screw shaft 12, the first screw blade 14, and the second screw blade 16. Therefore, the separated liquid partition 17 separates one end 20 side from the other end 22 side at the installed position (intermediate position 40).

Specifically, the separated liquid partition wall portion 17 extends from the space between the first screw blade 14 and the second screw blade 16 on the outer peripheral surface of the screw shaft 12 toward the outer side in the radial direction of the screw shaft 12. .. That is, the separated liquid partition wall portion 17 is a plate-shaped member whose distal end portion is attached to the outer peripheral surface of the screw shaft 12 and which extends radially outward toward the distal end portion. The separated liquid partition wall portion 17 has one side surface on the one end 20 side connected to the first screw blade 14, and the other side surface on the other end 22 side connected to the second screw blade 16. From one side surface to the other side surface in the extending direction E. Then, the tip of the separated liquid partition 17 extends along the radial direction of the screw shaft 12 to the same position as the tip of the first screw blade 14 and the second screw blade 16. That is, the separated liquid partition wall portion 17 forms a slit H between itself and the inner peripheral surface of the caging 10, like the first screw blade 14 and the second screw blade 16.

Since the separation liquid partition wall portion 17 is provided in the first space T1, it separates the charging space T0 from the first space T1 on the other end 22 side of the charging space T0. That is, the separation liquid partition wall portion 17 dams the target object A in the input space T0 and suppresses the entry of the target object A into the first space T1 on the side of the other end 22 with respect to itself. Since the separated liquid partition wall portion 17 is provided at the intermediate position 40, the separated liquid partition wall portion 17 is located closer to the other end portion 22 side than the position where the target object inlet 27 is provided. The separated liquid partition wall portion 17 is provided at the intermediate position 40, that is, at the boundary position of the first space T1 with respect to the input space T0. However, the separated liquid partition wall portion 17 is not limited to being provided at the intermediate position 40 as long as it is in the first space T1, and may be provided between the intermediate position 40 and the end portion position 42. However, it is preferable that the separation liquid partition wall portion 17 is provided closer to the intermediate position 40 than the end position 42.

The target object partition 18 is a baffle that prevents the target A from flowing out to the separated liquid discharge port 26. The object partition wall portion 18 is provided in the second space T2 on the other end 22 side of the separated liquid partition wall portion 17. It is more preferable that the object partition wall portion 18 is provided at the end (here, the second position 36) on the other end 22 side of the second space T2. The object partition wall portion 18 is in contact with the screw shaft 12, the first screw blade 14, and the second screw blade 16 in the second space T2. Further speaking, the object partition wall portion 18 is arranged so as to overlap with a region surrounded by the screw shaft 12, the first screw blade 14, and the second screw blade 16. Therefore, the separated liquid partition 17 separates one end 20 side from the other end 22 side at the installed position (second position 36).

Specifically, the object partition wall portion 18 extends from the space between the first screw blade 14 and the second screw blade 16 on the outer peripheral surface of the screw shaft 12 toward the outer side in the radial direction of the screw shaft 12. .. That is, the object partition wall portion 18 is a plate-shaped member whose distal end portion is attached to the outer peripheral surface of the screw shaft 12 and which extends radially outward toward the distal end portion. The object partition wall portion 18 has one side surface on the one end portion 20 side connected to the second screw blade 16 and the other side surface on the other end portion 22 side connected to the first screw blade 14. From one side surface to the other side surface in the extending direction E. Then, the tip end portion of the object partition wall portion 18 extends to the same position as the tip end portions of the first screw blade 14 and the second screw blade 16 along the radial direction of the screw shaft 12. That is, the object partition wall portion 18 forms the slit H between the inner peripheral surface of the caging 10 and the first screw blade 14 and the second screw blade 16 as well.

Here, a space between the second position 36 of the first screw blade 14 (where the winding of the first screw blade 14 ends) and the other end 22 is defined as a separated liquid discharge space T3. The separated liquid discharge space T3 is a space that communicates with the separated liquid discharge port 26. Since the object partition wall portion 18 is provided in the second space T2, it blocks the second space T2 on the one end 20 side from itself and the separated liquid discharge space T3. That is, the target object partition wall portion 18 dams the target object A in the second space T2 closer to the one end portion 20 side than itself, and enters the target object A into the separated liquid discharge space T3 (separated liquid discharge port 26). Is suppressed. The separated liquid discharge space T3 communicates with the second space T2 on the other end 22 side of the object partition wall portion 18. The separated liquid discharge space T3 communicates with the first space T1 on the other end 22 side of the separated liquid partition 17.

The inclination adjusting unit 19 is attached to the caging 10. The inclination adjusting unit 19 adjusts the inclination angle θ of the caging 10. The inclination angle θ is an inclination angle of the central axis along the extending direction E of the caging 10 with respect to the horizontal direction X (ground surface G). The inclination adjusting unit 19 adjusts the value of the inclination angle θ so that the central axis of the caging 10 is located downward along the vertical direction Z as it goes to the other end 22. However, the inclination adjusting unit 19 may adjust the value of the inclination angle θ so that the central axis of the caging 10 is along the horizontal direction X, that is, the extending direction E is parallel to the horizontal direction X.

(Operation of screw conveyor type separator)
Next, the operation of the screw conveyor type separation device 1 configured as described above and the behavior of the object will be described. 2 and 3 are schematic diagrams for explaining the operation of the screw conveyor type separation device according to the present embodiment.

As shown in step S10 of FIG. 2, in the screw conveyor type separation device 1, the target object A is charged into the caging 10 from the target object inlet 27. The object input port 27 opens in the single screw section K1. Therefore, the target object A is loaded into the loading space T0. Here, the other end 22 side of the caging 10 is inclined downward in the vertical direction Z. Then, the object A contains a liquid component and has fluidity. Therefore, when the object A in the charging space T0 is deposited up to the upper side along the vertical direction Z with respect to the screw shaft 12, the target A surpasses the screw shaft 12 and spirals in the direction E1 side along the first screw blade 14. Moving. The object A flows into the second space T2 in the double screw section K2. The direction E1 is a direction along the extending direction E, and is a direction from one end 20 to the other end 22. A direction E2 described below is a direction opposite to the direction E1, that is, a direction from the other end 22 toward the one end 20. In addition, in the example of step S10, the target A is input before the screw shaft 12 rotates, but the target A may be started while the screw shaft 12 is rotated.

The object A that has flowed into the second space T2 spirally moves in the second space T2 in the direction E1 when being accumulated up to the upper side of the screw shaft 12 in the vertical direction Z in the second space T2. .. The object partition wall portion 18 is provided at the end on the other end 22 side in the second space T2. Therefore, the target A is blocked by the target partition 18 and remains in the second space T2, and does not enter the separated liquid discharge space T3.

The target A in the input space T0 is blocked by the separation liquid partition 17 and does not enter the first space T1 on the other end 22 side of the separation liquid partition 17. Although the slit H is provided between the charging space T0 and the first space T1, the target A (solid component thereof) cannot pass through the slit H as described above. Therefore, the object A in the input space T0 does not flow into the first space T1 on the other end 22 side of the separated liquid partition 17. Similarly, the object A in the second space T2 also does not flow into the first space T1 on the other end 22 side of the separated liquid partition 17.

The target A contains a liquid component. As described above, the slit H conducts the liquid component in the target object, that is, the separated liquid C. Therefore, the separated liquid C from the object A in the input space T0 is introduced into the first space T1 via the slit H. Similarly, the separation liquid C is also introduced into the first space T1 through the slit H from the target object A that has flowed into the first space T1.

Next, as shown in step S12 of FIG. 2, the screw conveyor type separation device 1 rotates the screw shaft 12 along the direction R while the object A is continuously charged. The first screw blade 14 and the second screw blade 16 rotate as the screw shaft 12 rotates. The object A spirally moves in the direction E2 by the rotation of the first screw blade 14 and the second screw blade 16. Further, the object A is gradually squeezed by the movement due to the rotation and the friction with the inner peripheral surface of the caging 10 accompanying the rotation. As a result, the separation liquid C is separated from the object A, and the water content of the object A decreases. Then, the compressed object A moves spirally in the second space T2 in the direction E2 and enters the charging space T0. The compressed object A that has entered the charging space T0 moves in a spiral direction while being further compressed in the charging space T0 in the direction E2 by rotation, and is discharged from the object discharge port 24 to the outside. ..

On the other hand, the separated liquid C separated from the object A gradually enters the first space T1 through the slit H and is stored in the first space T1. The first space T1 is isolated from the second space T2 in a region other than the slit H. Therefore, the separated liquid C is separated from the object A in a region other than the region of the slit H to be in a non-contact state. As a result, the separated liquid C is stored in the first space T1 and gradually increases.

The first space T1 on the other end 22 side of the separated liquid partition 17 is spatially continuous in a spiral shape. Therefore, when the water level of the separated liquid C in the first space T1 is above the vertical direction Z of the screw shaft 12, the separated liquid C gets over the screw shaft 12 and spirally moves in the direction E1. The separated liquid C that has sequentially moved in the direction E1 in the first space T1 finally enters the separated liquid discharge space T3 and is discharged from the separated liquid discharge port 26. Further, in the caging 10, the other end 22 side is inclined downward along the vertical direction Z. Therefore, the water level of the separated liquid C in the first space T1 tends to be higher than that of the screw shaft 12, and a larger amount moves in the direction E1. Therefore, the screw conveyor type separation device 1 can increase the discharge amount of the separation liquid C. Further, even if the water level of the separated liquid C in the first space T1 rises, the separated liquid partition wall portion 17 prevents the separated liquid C from entering the input space T0. Therefore, the reduction of the dehydration efficiency (separation efficiency) of the object A is suppressed.

In this way, the screw conveyor type separation device 1 charges the target object A into the charging space T0, and the separation liquid partition wall portion 17 moves the object A into the first space T1 on the other end 22 side of the separation liquid partition wall portion 17. , Stop the entry of the object A. Therefore, this screw conveyor type separation device 1 appropriately dehydrates the object A by rotating the first screw blade 14 and the second screw blade 16, and at the same time, removes the object A into the separated liquid C separated by the dehydration. It becomes possible to suppress the mixture of

In addition, in the example of FIG. 2, the other end portion 22 of the caging 10 is described as being inclined downward in the vertical direction Z. However, as shown in FIG. 3, even when the caging 10 is along the horizontal direction X, it is possible to suppress the mixing of the target A into the separated liquid C while appropriately dehydrating the target A. As shown in step S20 of FIG. 3, when the object A charged in the charging space T0 is accumulated up to the upper side in the vertical direction Z with respect to the screw shaft 12, the object A passes over the screw shaft 12 and the first screw blade 14 Along both directions E1 and E2. The object A moved in the direction E1 flows into the second space T2 in the double screw section K2. However, the object A is blocked by the separation liquid partition wall portion 17 and does not enter the first space T1 on the other end 22 side of the separation liquid partition wall portion 17. On the other hand, the separated liquid C enters the first space T1 via the slit H.

Next, as shown in step S22 of FIG. 3, the screw conveyor type separation device 1 rotates the screw shaft 12 along the direction R while the target A is continuously charged. The thrown object A is deposited while moving to the second space T2, gets over the screw shaft 12, and moves in the direction E1. However, the target object A in the second space T2 is blocked by the target object partition wall portion 18, remains in the second space T2, and does not enter the separated liquid discharge space T3. On the other hand, the rotation of the screw shaft 12 causes the object A to move in a spiral shape while being squeezed in the direction E2. As a result, the compressed object A moves spirally in the input space T0 in the direction E2 and is discharged from the object discharge port 24 to the outside.

The separated liquid C separated from the object A is stored in the first space T1 and the water level gradually increases. When the water level of the separated liquid C in the first space T1 becomes higher than the vertical direction Z of the screw shaft 12, the separated liquid C gets over the screw shaft 12 and moves spirally in the directions E1 and E2. To do. However, the separated liquid partition 17 is provided in the first space T1. Therefore, the movement in the direction E2, that is, the movement in the charging space T0 is blocked by the separation liquid partition wall portion 17. Further, the separated liquid C is also blocked by the object A accumulated in the charging space T0, and the movement to the charging space T0 is restricted. Therefore, the separated liquid C is discharged from the separated liquid discharge port 26 through the separated liquid discharge space T3.

In this way, the screw conveyor type separation device 1 suppresses the mixing of the target object A into the separated liquid C while appropriately performing the dehydration of the target object A even when the caging 10 is along the horizontal direction X. You can

As described above, the screw conveyor type separation device 1 according to the present embodiment includes the caging 10, the screw shaft 12, the first screw blade 14, the second screw blade 16, and the separation liquid partition wall portion 17. .. The caging 10 is a tubular member in which an object discharge port 24 is opened at one end 20, an separated liquid discharge port 26 is opened at the other end 22, and an object input port 27 is opened at an intermediate part 23. Is. The screw shaft 12 is provided inside the caging 10 and extends along the extending direction E. The first screw blade 14 extends from the first position 34 between the one end portion 20 and the intermediate portion 23 to the second position 36 between the intermediate portion 23 and the other end portion 22 from the outer periphery of the screw shaft 12. It extends spirally on the surface. The second screw blade 16 is disposed in a predetermined direction along the extending direction E with respect to the first screw blade 14 from the intermediate position 40 on the other end 22 side of the intermediate portion 23 toward the other end 22 side. It extends spirally on the outer peripheral surface of the screw shaft 12 so as to be spaced apart. The second screw blade 16 forms a first space T1 between one surface 16a of the two surfaces facing the first screw blade 14 and the first screw blade 14 facing the one surface 16a. In addition, the second screw blade 16 forms a second space T2 between the other surface 16b of the two surfaces facing the first screw blade 14 and the first screw blade 14 facing the other surface 16b. To do. The separated liquid partition wall portion 17 is provided in the first space T1, and prevents the target A from entering the first space T1 on the other end 22 side of the position where it is provided. The screw conveyor type separation device 1 squeezes the target object A input from the target object input port 27 by the rotation of the screw shaft 12 to separate the separation liquid C, and moves the separation liquid C in the first space T1. Then, the compressed target object A is discharged from the separated liquid discharge port 26, moved in the second space T2, and discharged from the target object discharge port 24.

The screw conveyor type separation device 1 according to the present embodiment moves the separation liquid C in the first space T1 and discharges the separation liquid C. Then, the screw conveyor type separation device 1 moves the target object A in the second space T2 and discharges the target object A from which the separation liquid C has been separated. The screw conveyor type separation device 1 thus suppresses the mixing of the target A and the separation liquid C by dividing the space for transferring the separation liquid C and the space for transferring the compressed target A in this way. , The dehydration efficiency of the object A is improved.

Further, in the present embodiment, only the first screw blade 14 is provided at the position of the target object input port 27 for inputting the target object A before dehydration, and the second screw blade 16 is connected to the target object input port 27. Is provided on the other end 22 side. That is, in the present embodiment, the first space T1 is provided on the other end 22 side of the object insertion port 27. Then, in the first space T1, a separation liquid partition wall portion 17 that prevents the target A from entering is provided. The screw conveyor type separation device 1 conveys and discharges the separated liquid C in the first space T1 on the other end 22 side of the separated liquid partition 17. Then, the screw conveyor type separation device 1 suppresses the object A from entering the first space T1 on the other end 22 side of the separated liquid partition 17 by the separated liquid partition 17. .. Therefore, the screw conveyor type separation device 1 according to the present embodiment can suppress the mixing of the object A into the separated liquid C.

Further, the separated liquid partition wall portion 17 is in contact with the screw shaft 12, the first screw blade 14, and the second screw blade 16, and is provided at a position where one end 20 side and the other end 22 side are provided. Isolate. The separated liquid partition 17 separates one end 20 side and the other end 22 side in the first space T1. Therefore, the separated liquid partition wall portion 17 can more appropriately suppress the entry of the target object A into the first space T1 on the other end 22 side of the separated liquid partition wall portion 17.

Further, the caging 10 is inclined such that the central axis moves downward in the vertical direction Z toward the other end 22. Therefore, in the screw conveyor type separation device 1, the relative water level of the separated liquid C with respect to the screw shaft 12 is increased in the first space T1 provided on the other end 22 side of the object input port 27. You can Therefore, this screw conveyor type separation device 1 makes it easier for the separated liquid C to flow toward the other end 22 side, and discharges the separated liquid C from the separated liquid discharge port 26 provided at the other end 22 is preferable. It becomes possible to do it. Further, even if the water level of the separation liquid C in the first space T1 rises, the separation liquid partition wall portion 17 suppresses the separation liquid C from flowing toward the one end portion 20 side to some extent, and the separation liquid C becomes the target A. To reduce the amount of re-mixing with. Therefore, the screw conveyor type separation device 1 can suppress a decrease in the dehydration efficiency (separation efficiency) of the object A.

Further, the screw conveyor type separation device 1 further includes an inclination adjusting unit 19. The inclination adjusting unit 19 adjusts the inclination angle of the caging 10. The screw conveyor type separation device 1 can appropriately control the discharge amount of the separation liquid C by adjusting the inclination angle of the caging 10.

Further, the screw conveyor type separation device 1 further includes an object partition wall portion 18. The object partition wall portion 18 is provided in the second space T2 on the other end 22 side of the separation liquid partition wall portion 17, and prevents the target A in the second space T2 from flowing out to the separation liquid discharge port 26. .. The target partition 18 suppresses the target A from flowing out to the separated liquid discharge port 26 even when a large amount of the target A is accumulated in the second space T2. Therefore, the screw conveyor type separator 1 can suppress the dehydration efficiency (separation efficiency) of the target object A by discharging the target object A more reliably from the target object discharge port 24. However, the object partition wall portion 18 does not necessarily have to be provided. In the case where the object partition wall portion 18 is not provided, for example, the outflow of the object A is stopped in a region of the other end 22 of the caging 10 below the separated liquid discharge port 26 in the vertical direction Z. Is possible.

Further, the separated liquid discharge port 26 is provided above the screw shaft 12 in the vertical direction Z. Since the separated liquid discharge port 26 is provided above the screw shaft 12, even if the object A flows out to the other end 22, the object A accumulates above the screw shaft 12. Until then, the outflow of the object A from the separated liquid discharge port 26 can be suppressed. The separated liquid discharge port 26 is preferably provided above the screw shaft 12 along the vertical direction Z when the object partition wall portion 18 is not provided. However, the separated liquid discharge port 26 may be provided at the same position as the screw shaft 12 in the vertical direction Z or below the screw shaft 12 in the vertical direction Z.

(First embodiment)
Next, a wastewater treatment system as a first embodiment including the above-mentioned screw conveyor type separation device 1 will be described. FIG. 4 is a configuration diagram showing a part of the wastewater treatment system according to the first embodiment.

As shown in FIG. 4, the wastewater treatment system 100 according to the first embodiment includes a settling basin 101, a pre-stage facility 102 arranged in the front stage of the settling basin 101, and a rear stage facility arranged in the rear stage of the settling basin 101. 103, a drawing pump 104, and a screw conveyor type separation device 1. The settling tank 101 is a solid-liquid separation tank for settling and separating the water to be treated supplied from the former equipment 102 into a separated liquid and sludge. The pre-stage facility 102 is a facility configured to have various treatment tanks such as a reaction tank for treating organic wastewater such as sewage. The post-stage facility 103 is a facility that includes, for example, an incinerator, and that incinerates or discards the sludge (concentrated sludge) discharged from the screw conveyor type separator 1. The drawing pump 104 is a sludge drawing means for drawing the sludge from the settling tank 101 and supplying the sludge to the screw conveyor type separating apparatus 1.

In this wastewater treatment system 100, at least a part of the water to be treated discharged from the upstream equipment 102 is supplied to the settling tank 101. In the settling tank 101, the supplied water to be treated is separated into a separated liquid and sludge. Then, the separated sludge is extracted from the lower part of the settling tank 101 by the extraction pump 104 and supplied to the screw conveyor type separation device 1. The sludge that has been pulled out is carried into the inside of the screw conveyor type separation device 1 as the target A through the target input port 27 (see FIG. 1).

In the screw conveyor type separation device 1, the separation liquid C is separated in the same manner as the above-described embodiment. The separated liquid C that has been separated is returned to the settling tank 101. The object A after being separated (after being squeezed and dehydrated) is conveyed to the post-stage facility 103 as concentrated sludge, and is incinerated or discarded. As described above, the wastewater treatment according to the first embodiment is executed.

According to the first example described above, the object A withdrawn from the settling tank 101 is concentrated using the screw conveyor type separation device 1 according to the above-described embodiment, and the separated liquid C is returned to the settling tank 101. ing. As a result, the concentration of the object A can be improved and the maintainability of the settling tank 101 can be greatly improved. That is, in many cases, intermediate water exists in the sedimentation tank 101. When such intermediate water is present, when the sludge (object A) is drawn out, the water content is drawn out preferentially over the sludge (object A). Therefore, there is a problem that the concentrated concentration does not increase even if the sludge (target A) is compressed. According to the first embodiment described above with respect to this problem, by disposing the screw conveyor type separation device 1 in the subsequent stage of the settling tank 101, only intermediate water is extracted from the sludge (object A) extracted. It can be separated and returned to the settling tank 101. Therefore, the concentration concentration of sludge (target A) can be improved, so that the concentration concentration of sludge (target A) can be improved even when intermediate water is contained in the settling tank 101 as in the conventional case. it can. Moreover, since the above-mentioned screw conveyor type separation device 1 can be manufactured at low cost, the wastewater treatment system 100 can also be realized at low cost. Further, even when the sludge (target A) is clogged in the caging 10, the clog can be easily removed by rotating the screw shaft 12 in the reverse direction with respect to the direction R.

(First Modification of First Embodiment)
Next, a modification of the above-described first embodiment will be described. FIG. 5 is a schematic diagram showing a settling tank for explaining a modification of the first embodiment. As shown in FIG. 5, in the first modification, the screw conveyor type separation device 1 according to the embodiment is provided below the sedimentation tank 101. Then, the sludge settled in the lower part of the settling tank 101 is transferred to the inside of the screw conveyor type separation device 1 through the target object inlet 27 (see FIG. 1) using a sludge recovery device (not shown) such as a funnel. Supply as item A. The screw conveyor type separation device 1 discharges the concentrated sludge (target A) to the outside, and returns the separated separated liquid C to the settling basin 101 through the inside or the outside through a pipe (not shown) or the like. The separated liquid C can be discharged to the outside. Other configurations are similar to those of the first embodiment described above.

(Second Modification of First Embodiment)
In addition, as a second modification, when a gravity settling tank such as the settling tank 101 is provided in the preceding stage of the screw conveyor type separating apparatus 1, in the settling tank 101, a bar-shaped member that stands upright on the upper side of the rake that scrapes sludge It is also possible to provide a picket fence (not shown). By providing the picket fence, the sludge can be settled in the settling basin 101 and so-called coagulation is promoted. Therefore, the separation of the object A and the separation liquid C by the screw conveyor type separation device 1 can be made more efficient, and the solid-liquid separation property can be greatly improved.

(Second embodiment)
Next, a wastewater treatment system as a second example including the screw conveyor type separation device 1 according to the above-described embodiment will be described. FIG. 6 is a configuration diagram showing a part of the wastewater treatment system according to the second embodiment.

As shown in FIG. 6, the wastewater treatment system 200 according to the second embodiment includes a reaction tank 201, a pre-stage facility 202 arranged in the front stage of the reaction tank 201, and a sedimentation tank arranged in the rear stage of the reaction tank 201. 204, extraction pumps 203a and 203b, and a screw conveyor type separation device 1.

The reaction tank 201 is composed of, for example, a plurality of biological reaction tanks. The biological reaction tanks constituting the reaction tank 201 are various biological reaction tanks such as an anaerobic tank, anoxic tank, and an aerobic tank. The pre-stage facility 202 is a facility configured to have a sand basin, a sloping plate sedimentation basin, and the like, for treating organic wastewater such as sewage. The drawing pump 203a is a sludge drawing means for drawing sludge such as activated sludge from the reaction tank 201 and supplying it as the object A to the screw conveyor type separating apparatus 1. Similarly, the drawing pump 203b is a sludge drawing means for drawing the sludge from the reaction tank 201 and supplying the sludge to the settling tank 204 in the subsequent stage. The settling tank 204 is a solid-liquid separation tank for settling and separating the water to be treated and the separated liquid C, which are respectively supplied from the reaction tank 201 and the screw conveyor type separation device 1, into separated liquid C and sludge (target A). ..

In the wastewater treatment system 200 according to the second embodiment, at least a part of the water to be treated discharged from the pre-stage facility 202 is supplied to the reaction tank 201. In the reaction tank 201, biological treatment such as nitrification treatment and denitrification treatment is performed on the water to be treated. The activated sludge in the reaction tank 201 is extracted by the extraction pumps 203a and 203b. The sludge extracted by the extraction pump 203a is supplied to the screw conveyor type separation device 1 as the object A and is carried in through the object input port 27 (see FIG. 1).

In the screw conveyor type separation device 1, the sludge (object A) that has been carried in is concentrated and the separation liquid C is separated. The separated liquid C that has been separated is supplied to the subsequent settling tank 204. On the other hand, the sludge and the water to be treated extracted from the reaction tank 201 by the extraction pump 203b are supplied to the settling tank 204. In the settling tank 204, a solid-liquid separation process by gravity settling is executed as in the first embodiment. As described above, the wastewater treatment according to the second embodiment is executed.

According to the second embodiment described above, by using the screw conveyor type separation device 1, the sludge (target A) is drawn out from the reaction tank 201 and is compressed and concentrated, and the compressed and condensed sludge (target A) is reacted. While returning to the tank 201, the separated liquid C is supplied to the settling tank 204 as a solid-liquid separation tank. As a result, the following problems can be solved.

That is, conventionally, the electric power used to operate the return pump (not shown) for returning the sludge (object A) from the settling tank 204 to the reaction tank 201 was extremely large. On the other hand, according to the second embodiment, since the sludge (target A) compressed and concentrated by using the screw conveyor type separation device 1 can be returned to the reaction tank 201, the sludge (target A) can be returned. The required power can be reduced significantly. Furthermore, by using the screw conveyor type separation device 1, solid-liquid separation can be sufficiently performed. As a result, the frequency of sludge withdrawal in the settling basin 204 can be reduced, so that power can be reduced in the wastewater treatment system 200 to save energy.

Further, conventionally, in the case of the structure in which the separation membrane is provided in the reaction tank 201, there is a problem that the initial cost and the burden required for maintenance of the equipment are large. On the other hand, instead of the separation membrane, the low-cost screw conveyor type separation device 1 can be introduced, so that the initial cost can be reduced. Further, since the maintenance of the screw conveyor type separation device 1 is easy, the burden of maintenance can be reduced, and the maintenance cost can be reduced.

Furthermore, according to the second embodiment, since the reaction tank 201 can be made to have a high MLSS, the load on the settling tank 204 can be reduced, and the extraction pumps 203a and 203b used for extracting sludge from the reaction tank 201. Power consumption can be reduced. Therefore, energy saving can be achieved in the wastewater treatment system 200.

The embodiments of the present invention have been specifically described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made based on the technical idea of the present invention. Further, the components described above include those that can be easily conceived by those skilled in the art, those that are substantially the same, and those within the so-called equivalent range. Furthermore, the components described above can be combined appropriately. Furthermore, various omissions, substitutions, or changes of the constituent elements can be made without departing from the scope of the above-described embodiment. For example, the numerical values given in the above embodiment are merely examples, and different numerical values may be used if necessary.

In the above-described embodiment, the screw shaft 12 is composed of a cylindrical shaft, but the screw shaft 12 is not necessarily limited to this shape. For example, the screw shaft 12 may have a so-called expanded diameter shape in which the diameter gradually increases from the other end 22 of the casing 10 toward the one end 20.

Further, in the above-described embodiment, the solid-liquid separation device for separating the sludge floc into solid and water is taken as an example, but the solid-liquid separation of the sludge floc is not necessarily limited to the solid-liquid separation. It is also possible to apply to various methods for separating.

Further, in the above-described embodiment, the position of the separated liquid discharge port 26 can be variously changed.

Further, in the above-described embodiment, the movement of the separated liquid C from the second space T2 to the first space T1 is performed through the slit H, but it is not necessarily limited to the configuration of the slit H. For example, at least a part of the first screw blade 14 or the second screw blade 16 is additionally provided with a filtering means having a mesh shape or a large number of minute holes, and the separated liquid C is moved from the second space T2 to the first space T1. It may be configured as possible.

Further, the screw conveyor type separation device 1 according to the above-described embodiment can be used as a pre-concentrator for a dehydrator, a simple concentrator for consumer use, a merge improvement screen, and the like.

In the first example of the above-described one embodiment, the sludge extracted by the extraction pump 104 is the sludge settled in the settling tank 101, but the sludge is not necessarily limited to the settled sludge. For example, floating sludge is likely to be generated in the sedimentation basin 101 during the summer, but the floating sludge can be extracted by the extraction pump 104 and supplied to the screw conveyor type separation device 1.

Further, in the above-described first example, an example in which the screw conveyor type separation device 1 according to one embodiment is combined with the settling tank 101 has been described, but the present invention is not necessarily limited to this mode. Specifically, for example, the filter concentrator and the screw conveyor type separator 1 can be combined. In this case, it is possible to install the above-mentioned screw conveyor type separation device 1 at the line for pulling out sludge in the filtration/concentration device or at the bottom of the filtration/concentration device. Here, in the filtration/concentration device, since the operation is an intermittent operation, the concentrated sludge is temporarily stored in the filtration/concentration device, and the sludge is withdrawn from below. Therefore, when the liquid is temporarily stored, the supernatant liquid stored in the upper part of the sludge is extracted together with the concentrated sludge. As a result, although there is a problem similar to the problem in the first embodiment described above, by using the screw conveyor type separation device 1 according to this embodiment, the supernatant liquid (supernatant water) is removed when sludge is drawn out. Since it can be separated, it becomes possible to stably increase the concentrated concentration of the concentrated sludge.

1 Screw Conveyor Type Separator 10 Caging 12 Screw Shaft 14 First Screw Blade 16 Second Screw Blade 16a One Surface 16b Other Surface 17 Separation Liquid Partition Wall 18 Object Partition Wall 19 Inclination Adjusting Part 20 One End 22 Other End part 23 middle part 24 target object discharge port 26 separated liquid discharge port 27 target object input port 34 first position 36 second position 40 intermediate position E extension direction T0 input space T1 first space T2 second space T3 separated liquid Discharge space

Claims (9)

A screw conveyor that squeezes the object that has been input from the object input port, discharges the pressed object from the object discharge port, and discharges the separated liquid separated from the object by pressing from the separated liquid discharge port. A mold separating device,
The object discharge port is opened at one end, the separated liquid discharge port is opened at the other end, and the object is at an intermediate portion between the one end and the other end. Cylindrical caging with an opening,
Provided inside the casing, a screw shaft extending along an extending direction which is a direction from the one end to the other end,
From a first position between the one end portion and the intermediate portion to a second position between the intermediate portion and the other end portion, which extends spirally on the outer peripheral surface of the screw shaft. 1 screw blade,
From the intermediate position on the other end side with respect to the intermediate part toward the other end side, the screw shaft is spaced a predetermined distance from the first screw blade along the extending direction. Spirally extending on the outer peripheral surface of, and forming a first space between one of the two surfaces facing the first screw blade and the first screw blade facing the one surface, A second screw blade forming a second space between the other surface of the two surfaces and the first screw blade facing the other surface;
A separation liquid partition wall portion that is provided in the first space and that blocks the entry of the object into the first space on the other end side from the position where the separation space is provided,
Have
The rotation of the screw shaft squeezes the target object introduced from the target object inlet to separate the separated liquid, and the separated liquid is moved in the first space and discharged from the separated liquid outlet. , Moving the compressed object in the second space and discharging it from the object discharge port,
Screw conveyor type separator. The separated liquid partition wall portion is in contact with the screw shaft, the first screw blade, and the second screw blade, and separates the one end side and the other end side at a position provided. The screw conveyor type separation device according to claim 1. The screw conveyor type separation device according to claim 1 or 2, wherein a center axis of the caging is inclined in a direction in which the central axis moves downward in the vertical direction toward the other end. The screw conveyor type separation device according to claim 3, further comprising an inclination adjusting unit that adjusts an inclination angle of the caging. It further has an object partition part which is provided in the second space on the other end side of the separated liquid partition part and which blocks the outflow of the object in the second space to the separated liquid discharge port. The screw conveyor device according to any one of claims 1 to 4. The screw conveyor type separation device according to any one of claims 1 to 5, wherein the separated liquid discharge port is provided vertically above the screw shaft. A wastewater treatment system comprising a solid-liquid separation tank for separating sludge from organic wastewater, and the screw conveyor type separation device according to any one of claims 1 to 6.
The screw conveyor type separation device is configured to concentrate the sludge discharged from the solid-liquid separation tank, and to return the separated liquid generated during the concentration of the sludge to the solid-liquid separation tank, a wastewater treatment system. .. The wastewater treatment system according to claim 7, wherein the screw conveyor type separation device is provided in the solid-liquid separation tank. A reaction tank for biologically treating organic wastewater, a solid-liquid separation tank for separating sludge from the organic wastewater, and the screw conveyor type separation device according to any one of claims 1 to 6. A wastewater treatment system comprising:
The screw conveyor type separation device draws out sludge from the reaction tank and concentrates it, and returns the concentrated sludge to the reaction tank, and the separated liquid generated at the time of concentrating the sludge into the solid-liquid separation tank. A wastewater treatment system that can be supplied.

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