JPS6038012A - Electroosmotic type dehydrator - Google Patents

Abstract

PURPOSE:To enhance dehydration capacity by preventing the side leakage of sludge supplied to a sludge passage from a dehydration part, by providing flange shaped electric insulating seal members to both side edge parts of a rotor for constituting one rotor. CONSTITUTION:Voltage is applied between a rotor 2 and a press conveyor 3 and sludge is continuously supplied from a hopper 1 toward a compression passage 9 while a conveyor 3 is driven by a motor. Sludge is conveyed from the inlet of the passage 9 toward an outlet side and dehydrated on the way of conveying process by mechanical compression and electroosmotic action and electric insulating seal member 21 are mounted to both left and right side edges of the rotor 2 so as to inlay the outer end thereof with the concaved groove 22 of the conveyor 3 to form a partition wall for partitioning both left and right sides of the sludge compression passage 19. Therefore, the side leakage of sludge to the outside from the passage 19 is prevented during conveyance and sufficient compression force can be added to sludge.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field to which the Invention Pertains] The present invention relates to an electroosmotic dehydrator for dewatering slurry such as sludge generated in a wastewater treatment process in a sewage treatment plant or human waste treatment plant.

[Prior art and its problems]

Conventionally, the sludge generated at the above-mentioned treatment plants was usually dehydrated and reduced in volume using a dehydrator, and then disposed of in a landfill in the form of a cake. However, in addition to the fact that the amount of sludge generated is increasing year by year,
Questions about the lack of land for landfill disposal 1-@hi:hrk8-tsu;
Nosi 0 Keni] 1 piece/1sL-su↓NJ+Wl-IL#
In order to achieve +m-r and + uses, a treatment method that composts sludge and uses it as fertilizer is attracting attention.

In this case, if the moisture content of the dehydrated cake could be reduced to about 50%, the sludge would self-fuse during incineration, eliminating the need for auxiliary fuel1. There are great benefits, such as eliminating the need for auxiliary materials for moisture content adjustment and auxiliary fuel for pre-drying. By the way, as mentioned above, sludge generated at sewage treatment plants, etc. contains a large amount of organic matter, so it has a strong bond with water and is extremely difficult to dehydrate. Even in the case of dehydration treatment using a filter press, which is said to have a water content of about ω%, the cake moisture content was at its limit.

Therefore, in order to improve the performance of dehydrators, various electroosmotic dehydrators have been devised, which perform dehydration by electroosmosis in addition to mechanical dehydration by applying an electric field to existing mechanical dehydrators. ing. For example, in a conventional belt press dehydrator, an electrode member is provided on the back side of the filter belt, and by applying a voltage between the electrode member and the opposing roll, the filter belt facing the roll and this roll is It is known that electric osmosis dehydration is performed by applying an electric field to the slurry supplied to the slurry squeezing passageway between the slurry and the slurry. However, in a normal belt press, the squeezing force between the roll and the filter belt is relatively weak, and even if an electric field is applied to this, the moisture content of the dehydrated cake can be reduced to 5.
In practice, it is not possible to lower the voltage to about 0h'.

For this purpose, an improved belt press dehydrator is equipped with a pressure mechanism using a hydraulic cylinder, spring, etc. on the back side of the belt to press the belt toward the roll and obtain a strong squeezing force. Proposed. However, this improved belt press can only be used for secondary dehydration of cakes that have been caked to some extent during the primary dehydration, and if slurry in an almost raw state with a moisture content of about 90% is directly processed, When supplied to a belt press, a portion of the slurry leaks out from between the filter belt and the roll during the dewatering and conveying process due to the strong squeezing force, making it impossible to put it to practical use.

[Purpose of the invention]

This invention was developed in consideration of the above points, and eliminates the drawbacks of the conventional machines, and prevents side leakage of slurry even when strong squeezing force is applied over the entire dewatering area from the slurry supply inlet to the outlet. An object of the present invention is to provide an electroosmotic dewatering machine with high dewatering performance, which can dewater sludge with a high water content to a low water content without any fear.

[Key points of the invention]

In order to achieve the above object, the present invention combines a rotating body constituting one electrode, and a press belt and a filter belt constituting the other electrode, which are stretched around a part of the circumferential area of the rotary body. A voltage is applied from the outside between the electrodes, and the press belt is rotated to move the sludge to be treated into the slurry squeezing passage defined between the rotating body and the facing surface of the filter belt. In a dewatering machine that performs electroosmotic dehydration treatment by supplying fluid, a sludge-shaped sludge-shaped thunderbolt is provided on both the left and right sides of the slurry squeezing passage, extending in the radial direction from the left and right edges of the rotating body. By providing a sealing member, it is possible to prevent the slurry supplied to the slurry passage from leaking from the dewatering section, thereby allowing effective dewatering by applying high squeezing force to the slurry with a high moisture content. This is what I did.

[Embodiments of the invention]

1 to 4 show embodiments of the present invention, and in each figure, l represents a hopper for supplying the slurry to be treated;
Reference numeral 2 denotes a rotary body having a drum structure, the peripheral wall of which is made of a conductive material, and is rotatably supported, and 3 is stretched across sprockets 4 to 7 so as to surround a part of the circumferential area of the rotary body 2. A press conveyor made of a conductive material, 8 a filter belt superimposed on the press conveyor 3 and serving as a furnace cloth stretched over its outer peripheral surface, (2) a drive motor for the press conveyor, 9 a filter belt that connects the press conveyor 3 8
10 is a dehydration receiver disposed in the lower area of the rotor 2, 11 is a dewatering cake discharge seat, and 12 is each of the above-mentioned parts. A frame 13 for assembling and supporting the elements connects the rotating body 2 and the press conveyor 3 to the rotating body 2 through a power supply line and a brush so as to apply a voltage between the two as opposed electrodes. This is a power supply device connected to the rotating shaft of the press conveyor sprocket.

As shown in FIG. 4, the press conveyor 3 has a pair of left and right endless chains 14 stretched over the sprockets 4 to 7, and chain chains of the left and right chains.
The frame is made up of a metal plate 15 that is passed between the locks, and this plate 15 is pressed toward the rotating body 2 from behind by the aforementioned pressing mechanism 9. That is, the pressure device 9 is installed behind the press conveyor 3 in the area around the rotating body 2, and as can be understood from FIG. The main block [6] is in contact with the back surface of the plate 3 and is supported by the frame 12 via a hydraulic cylinder 18. The pressure applied to the press conveyor 3 is adjusted by the hydraulic pressure applied to the hydraulic cylinder 18. Note that, as a matter of course, the rotating body 2 is supported by the frame 12 in an electrically insulated manner.

With the above configuration, the press conveyor 3 is located around the rotating body 2.
A slurry squeezing passage 19 is defined between the opposing faces of the press conveyor 3, and a slurry supply hopper 1 is installed on the inlet side upstream of the press conveyor 3 in its moving direction. Here, a voltage is applied between the rotating body 2 and the press conveyor 3, and the drive motor 3
While driving the press conveyor 3 in the direction of arrow A by 0,
If the slurry is continuously supplied from the hopper 1 toward the slurry squeezing passage 19, the slurry will be conveyed from the entrance to the exit side of the passage 19, and in the middle of the process, it will be compressed mechanically as well as by electroosmotic action. The water in the charged slurry flows toward the cathode electrode according to the direction of the electric field, is discharged here, and then passes through the filter belt to be dehydrated. The dehydrated cake is then discharged from the outlet through a discharge chute 11, while the filtrate that has passed through the filter belt 8 flows down to the dewatering receiver 10 and is drained out of the system. In order to prevent the dehydrated cake from clinging to the circumferential wall of the rotating body 2, a stripping wire is installed around the circumferential area of the rotating body 2.

According to the present invention, sealing members 21 made of an electrically insulating material as shown in FIG. 3 are attached to both left and right edges of the rotating body 2.

This sealing member 21 is, for example, a collar-shaped ring made of electrically insulating hard rubber, and is attached so as to protrude in the radial direction from the outer peripheral surface of the rotating body 2, and its outer end contacts the press conveyor side. It serves as a partition wall that partitions both left and right sides of a slurry squeezing passage 19 defined between the opposing surfaces of the rotating body 2 and the filter belt 8. In order to make full use of this sealing function, grooves n into which the sealing member 21 is fitted are formed at both left and right ends of the play 15 in the press conveyor 3. The depth of this groove n is determined so as not to inhibit the rotation of the rotary body 2, and the groove width is determined so that the filter belt 8 stacked on the press conveyor and the side surface of the seal member 21 will slide. It is being

By providing the electrically insulating sealing member 2 in this way, the slurry put into the slurry squeezing passage 19 will not leak outside the passage during transportation, and therefore the above-mentioned Through the pressure mechanism 91, Heat tends to raise the temperature of the slurry, making it more fluid.
The sealing mechanism prevents the leakage of slurry, which can greatly contribute to improving the dewatering effect. In order to smoothly discharge the dewatered filtrate of the slurry, in the illustrated embodiment, the plate 15 of the press conveyor is provided with a drainage hole n extending from the back side.

Next, the results of tests conducted by the inventor using the dehydrator having the above structure are shown in the following table. In this test, raw sludge from a sewage treatment plant was pretreated using a polymer as a flocculant.

As is clear from the table above, the results of the actual root test demonstrated that permanent sewage sludge can be dehydrated to a water content of about 50%. Since the above dehydration can be achieved without using lime as a coagulation aid, the low heat value of the dehydrated cake is high as shown in the table, and this value is above the self-combustion limit of 900-950 in a general incinerator. = Sufficiently higher than Ap, "Therefore, self-combustion disposal of the dehydrated cake is possible.Also, in actual machine testing, no side leakage of sludge was observed even when high squeezing pressure was applied by the pressurizing mechanism as shown in the table. It has been confirmed that no sludge loss occurs.

〔Effect of the invention〕

As described above, according to the present invention, a dehydration device is configured by combining a rotating body, a press conveyor, and a filter belt, and performs electroosmotic dehydration by applying a voltage between the rotating body and the press conveyor. By attaching a sealing member to the rotating body of the machine and partitioning off both the left and right sides of the slurry squeezing passage, there is no risk that the slurry being conveyed will leak from the passage during the slurry dewatering process. Moisture content is 90, which is almost like a raw state while applying high compression pressure.
High performance suitable for the above sludge treatment that can be dehydrated to a water content of about 50% by directly supplying slurry of 1.
An electroosmotic dehydrator was realized. In addition, by adopting this dehydrator, incineration, which is a later process at a sludge treatment plant,
Advantages such as being able to contribute to a significant reduction in running costs required for composting are obtained.

BRIEF DESCRIPTION OF THE DRAWINGS Each figure shows an embodiment of the present invention, and FIG. 1 is a sectional view of the main dewatering part, and FIG. 4 is a partially enlarged perspective view of the press conveyor. DESCRIPTION OF SYMBOLS 1... Sludge input hopper, 2... Rotating body, 3... Press conveyor, 4-7... Sprocket, 8... Filter belt, 9... Pressure device, 13... Power supply Device, 19... Slurry compression passage, 21... Seal member, 2
2...concave groove.

Claims (1)

[Scope of Claims] 1) A rotating body whose peripheral wall is made of a conductive material, a press conveyor made of a conductive material stretched around a part of the circumferential area of the rotating body, and a press conveyor that is stacked on the press conveyor and on its outer circumferential surface. The press conveyor drive device includes a filter belt stretched around the press conveyor, a power supply device that applies a voltage between the rotary body and the press conveyor with the rotating body and the press conveyor as opposing electrodes, and applies a voltage between the rotary body and the press conveyor. In this state, the sludge to be treated is continuously supplied from the inlet side to the slurry squeezing passage defined between the opposing surfaces of the rotating body and the filter belt, thereby dewatering the sludge by electroosmosis. In an electroosmotic dewatering machine that discharges a dehydrated cake from the outlet side, a brim-shaped electrically insulating seal member protrudes radially from both left and right edges of the rotating body and partitions both left and right sides of the slurry pressing passage. Electricity 2)! The electroosmotic dehydrator according to claim 1, characterized in that grooves that fit into the seal member are formed at both left and right ends of the press conveyor side facing the seal member. Dehydrator. 3) In the dehydrator according to any one of claims 1 and 2, it is provided that the sealing member is an electrically insulating hard rubber ring fitted into the outer peripheral edge of the rotating drum. Characteristic electroosmotic dehydrator.