JP4267773B2 - Sludge filtration dehydrator - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
In the present invention, the sludge obtained by the coagulation sedimentation apparatus at the time of water treatment is subjected to filtration and dehydration treatment as a preconcentration before the final dehydration treatment such as sun drying treatment, pressure dehydration treatment and vacuum dehydration treatment. More particularly, the present invention relates to a filter dehydrator in which the filter cloth cylinder of the filter dehydrator can be easily regenerated and the solid matter deposited on the filter cloth cylinder can be easily recovered.
[0002]
[Prior art]
In water purification treatment that obtains clean water using river water or lake water as raw water, a coagulating sedimentation treatment is applied to the raw water as a primary treatment of the raw water.
In the coagulation-precipitation treatment, an inorganic coagulant is added to raw water, mixed, and then introduced into a coagulation sedimentation tank to generate insoluble flocs. Further, suspended solids in the raw water are adsorbed to the flocs, and suspended solids The floc that has adsorbed the substance is removed by precipitation to obtain clear treated water.
[0003]
On the other hand, flocs that have adsorbed suspended solids and settled and separated in the coagulation sedimentation tank accumulate on the bottom as coagulation sedimentation sludge, are periodically discharged from the coagulation sedimentation tank, and temporarily store the coagulation sedimentation sludge. It is transferred to the sludge sedimentation tank via the tank or sludge storage tank.
The sludge settling tank is a device that concentrates the coagulated sediment sludge by the sedimentation separation method.The coagulated sediment sludge is allowed to stand for a long period of time, and the solid matter is further settled and separated from the settled coagulated sediment sludge. Make it high.
Next, the concentrated sludge is discharged from the sludge concentration tank, and finally disposed as a solid after being subjected to dehydration treatment such as sun drying, pressure dehydration, and vacuum dehydration.
[0004]
By the way, when performing dehydration processes such as sun drying, pressure dehydration, and vacuum dehydration, the performance of the apparatus for performing the dehydration process greatly depends on the concentration of the treated sludge. For example, when the weight of the solid is the same, the higher the sludge concentration, the smaller the sludge capacity, so that the apparatus can be miniaturized.
Therefore, it is desirable to further concentrate the sludge before subjecting the sludge discharged from the sludge concentration tank to dehydration treatment such as sun drying, pressure dehydration, and vacuum dehydration.
Therefore, in order to further concentrate the sludge discharged from the sludge precipitation concentration tank, a filtration and dewatering type sludge concentrating device has been conventionally used.
In the above description, water purification treatment is taken as an example, but the same applies to sludge generated in wastewater treatment.
[0005]
Here, with reference to FIG. 5, the structure of the conventional filtration dewatering-type sludge concentration apparatus is demonstrated. FIG. 5 is a schematic cross-sectional view showing the configuration of a conventional sludge filtration and dehydrator.
The filtration dewatering-type sludge concentrating device includes a filtration dehydrator for filtering and dewatering sludge as a main part. As shown in FIG. 5, the conventional filter dehydrator 10 includes a vertical container 12, and the container 12 is obtained by filtering sludge with a lower sludge chamber 14 into which sludge is introduced by a partition plate 18. It is divided into an upper liquid collecting chamber 16 for collecting the filtrate. In the sludge chamber 14, a filter cloth cylinder 20 fixed to the partition plate 18 at the upper end is provided so as to hang down from the sludge chamber 14.
The filter cloth cylinder 20 is configured as a filter element in which a filter cloth is stretched as a filter medium on the outer surface of a cylindrical frame body made of a cylindrical mesh body or a perforated plate. A cloth cylinder 20 is attached.
[0006]
The sludge chamber 14 of the container 12 is provided with a sludge inlet 24 connected to the sludge supply pipe 22 in order to introduce the sludge into the sludge chamber 14, and is dropped from the filter cloth of the filter cloth cylinder 20. In order to discharge the sludge accumulated at the bottom of the sludge chamber 14, a sludge discharge port 26 is provided at the bottom. The sludge discharge port 26 is connected to a sludge discharge pipe 30 via a plate type on-off valve 28 that can be opened and closed quickly.
The liquid collection chamber 16 is provided with a filtrate outlet 34 connected to the filtrate pipe 32 in order to discharge the collected filtrate. A pressurized air pipe 36 is connected to the filtrate pipe 32, and pressurized air is introduced from the filtrate outlet 34 into the liquid collection chamber 16 and then into the filter cloth cylinder 20.
[0007]
In order to filter and dewater sludge with the filter dehydrator 10, first, the sludge is pressed into the sludge chamber 14 from the sludge supply pipe 22 via the sludge inlet 24 at a predetermined pressure. Solid matter in the sludge is trapped on the filter cloth surface of the filter cloth cylinder 20, and the liquid in the sludge flows into the liquid collection chamber 16 as a filtrate, and is discharged from the filtrate pipe 32 through the filtrate discharge port 34.
As the sludge is continuously filtered and dehydrated, the solid matter trapped on the filter cloth surface of the filter cloth cylinder 20 accumulates, and the pressure loss when the filtrate permeates the filter cloth cylinder 20 gradually increases.
[0008]
Therefore, when the pressure loss reaches a predetermined magnitude, the filter cloth cylinder 20 is regenerated. In the regenerative operation, the on-off valve (not shown) of the sludge supply pipe 22 is closed to stop the introduction of sludge, and the on-off valve (not shown) of the filtrate pipe 32 is closed. Next, the vent pipe (not shown) provided at the top of the liquid collection chamber 16 is opened, and then the drain pipe (not shown) provided at the bottom of the sludge chamber 14 is opened, and the sludge in the sludge chamber 14 is opened. Is discharged.
After the drain pipe and the vent pipe are closed, pressurized air is introduced from the pressurized air pipe 36 into the liquid collecting chamber 16 and further into the filter cloth cylinder 20, and the inside of the filter cloth cylinder 20 is opposite to the permeation direction of the filtrate. Then, the filter cloth surface is pressed to remove the solid matter deposited on the filter cloth surface, and is deposited on the bottom of the sludge chamber 14.
Next, the plate type on-off valve 28 is quickly opened, and the accumulated solid matter is pumped through the sludge discharge pipe 30 by the pressure of the pressurized air in the sludge chamber 14.
[0009]
[Problems to be solved by the invention]
However, the conventional filtration dehydrator described above has a problem in that the solids detachment operation with pressurized air does not actually function as expected and the solids are difficult to detach.
Although there is a difference depending on the properties of the sludge, the sludge adheres firmly to the filter cloth surface of the filter cloth cylinder. Since pressure remains on the filter cloth surface, the pressure loss does not decrease so much.
In addition, when a part of the solid matter accumulated on the filter cloth surface of the filter cloth cylinder is desorbed at an early stage, the pressurized air flows out from the desorbed part intensively and the undesorbed part remains over a wide area. .
[0010]
SUMMARY OF THE INVENTION An object of the present invention is to provide a sludge filtration and dehydrator that makes it easy to drop solids from a filter cloth cylinder.
[0011]
By the way, a so-called expansion / contraction type filter cloth cylinder which has been devised so that solids can be easily removed has been proposed (for example, JP-A-4-87606) and put into practical use.
Basically, the expansion / contraction type filter cloth cylinder is composed of a cylindrical or bag-like filter and a filtrate collecting member inserted into the filter and protruding at one end to the outside of the filter. The filter is made of a flexible filter sheet. The filtrate collecting member is wrapped and flattened by the pressure from the outside to the inside of the filter at the time of filtration, and is deformable so as to expand by the pressure from the inside to the outside of the filter at the time of peeling the filter cake. The collecting member has a filtrate guide path that opens into the filter and guides the filtrate in the filter to the outside of the filter.
[0012]
Furthermore, with reference to FIG.6 and FIG.7, the structure of an example of the expansion / contraction type filter cloth cylinder is given and demonstrated. 6 is a longitudinal front view of the expansion / contraction type filter cloth cylinder, FIG. 7A is a cross-sectional view of the filter cloth cylinder at the time of filtration dehydration, and FIG. 7B is a cross-sectional view of the filter cloth cylinder at the time of regenerative operation. It is.
As shown in FIG. 6, one example of the expansion / contraction type filter cloth cylinder 40 includes a cylindrical filter 42 and a filtrate collecting tube 44 having openings at both ends inserted into the filter 42 from one end of the filter 42. I have.
The filter 42 is formed by fitting short cylindrical caps 48 </ b> A and 48 </ b> B at both ends of the opening of a hose-like flexible filter sheet 46 made of cotton and fastening the fitting portion with a band 50.
[0013]
The filtrate collecting tube 44 has a large number of small through holes as a filtrate collecting port 52 on the peripheral surface of the portion inserted into the filter 42, and passes through the center of the cap 48 </ b> A at one end of the filter 42 to the other end. The cap 48B is inserted into the vicinity of the cap 48B and protrudes outward from the cap 48A with an appropriate length to form a protruding portion 54. As a result, the filtrate collecting tube 44 uses the hollow portion in the tube as the filtrate guide path 56 and allows the inside of the filter 42 to communicate with the outside through the open end of the protruding portion 54.
The filter 42 is fixed to the partition plate 18 by passing the protruding portion 54 of the filtrate collecting tube 44 through the partition plate 18 and screwing the nut 58 to the thread of the protruding portion 54.
[0014]
When sludge is press-fitted into the sludge chamber 14 (see FIG. 5) of the filter dehydrator 10 equipped with the expansion / contraction type filter cloth cylinder 40, the region excluding both ends of the filter 42 is filtrated as shown in FIG. The collection tube 44 is wrapped and contracted flatly, the solid matter in the sludge is captured on the outer surface of the filter 42, and the filtrate passes through the filtrate collection port 52 of the filtrate collection tube 44, and then passes through the filtrate guide path 56 and protrudes 54. Liquid is collected from the open end of the liquid into the liquid collection chamber 16 (see FIG. 5).
In the regenerative operation of the expansion / contraction type filter cloth cylinder 40, pressurized air is blown into the filtrate collection tube 44 from the opening end of the protruding portion 54 via the liquid collection chamber 16. The compressed air flows out from the filtrate collecting port 52 into the filter 42 and expands the flatly contracted filter 42 into a cylindrical shape as shown in FIG. To blow out.
The solid matter accumulated in the filter 42 is surely peeled off and dropped off by the impact effect that the filter sheet 46 expands from a flat shape to a cylindrical shape and the blowing of pressurized air.
[0015]
The above-mentioned expansion / contraction type filter cloth cylinder is evaluated as a filter cloth cylinder that is easy to detach solids, and when an expansion / contraction type filter cloth cylinder is used, it is necessary to add a configuration that makes it easier to detach solids. Although not present, an object of the present invention is to provide a filter dehydrator having a wide application range that can be applied not only to the type of the filter cloth cylinder but also to the above-described expansion / contraction filter cloth cylinder.
[0016]
[Means for Solving the Problems]
In order to achieve the above object, the sludge filtration and dehydrator according to the present invention includes a lower sludge chamber for introducing sludge, and an upper liquid collection chamber for collecting filtrate obtained by filtering sludge. It is equipped with a vertical container partitioned by a partition plate, the filter cloth cylinder fixed to the partition plate at the upper end is suspended in the sludge chamber, and the solid matter in the sludge introduced into the sludge chamber is captured by the filter cloth tube. In the sludge filtration and dehydrator, the sludge is filtered and dehydrated by flowing the filtrate that has passed through the filter cloth tube to the outside through the collection chamber.
A frame size larger than the outer shape of the filter cloth cylinder, penetrating the lower part of the filter cloth cylinder, and at least the number of the hole frames that collide with the oscillating or vibrating filter cloth cylinder, A frame plate provided in the same arrangement as that of the filter cloth cylinder and provided so as to cross the sludge chamber, and a frame so that pressurized air is intermittently or continuously ejected in a direction intersecting the filter cloth cylinder. A pressurized air jet nozzle provided on the container wall at at least one of the upper position and the lower position of the plate;
Each filter cloth cylinder is made to penetrate the hole frame, respectively.
[0017]
In the present invention, when solid matter accumulates on the filter cloth surface of the filter cloth cylinder and the filtration pressure loss increases, the sludge and the filtrate are extracted from the sludge chamber and the liquid collection chamber of the filter dehydrator, and then the pressurized air The jet nozzles eject the pressurized air intermittently or continuously in a direction crossing the filter cloth cylinder, and swing or vibrate the filter cloth cylinder to collide with the hole frame. As a result, the solid matter deposited on the filter cloth surface is detached from the filter cloth surface due to the impact and vibration effect of the filter cloth cylinder when the filter cloth cylinder collides with the hole frame, and falls off.
When the pressurized air is ejected from the ejection nozzle, the pressurized air may be blown from the inner side to the outer side of the filter cloth tube as opposed to the permeation direction of the filtrate, as in the prior art.
[0018]
The filter cloth cylinder used in the filter dehydrator according to the present invention is not limited in the type of the filter cloth cylinder, and may be a normal non-deformable filter cloth cylinder or an expansion / contraction filter cloth cylinder. Moreover, there is no restriction | limiting also in the material of a filter cloth, For example, a cotton cloth, a plastic filter cloth, and a metal filter cloth may be sufficient.
The shape of the hole frame is not limited, and may be, for example, a circle, a triangle, a polygon such as a quadrangle, a hexagon, or the like, but a circle is practical because the collision effect is the same in all directions. Further, the hole frame may be formed by punching a plate-like body, or may be formed by a net-like body, or may be formed by combining rod-like bodies in a lattice shape.
The installation position of the pressurized air ejection nozzle is above or below the frame plate, or both, and the ejection nozzle is installed at a position where the filter cloth cylinder is most likely to swing or vibrate.
[0019]
Although there is no restriction on the manner in which the pressurized air is ejected, the plurality of ejection nozzles are preferably divided into a plurality of groups at at least one of the upper position and the lower position of the frame plate. The filter cloth cylinder is provided on the container wall of the sludge chamber, and the blowing and stopping of the pressurized air are controlled for each group.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below specifically and in detail with reference to the accompanying drawings.
Embodiment Example This embodiment example is an example of an embodiment of a sludge filtration dehydrator according to the present invention, and FIG. 1 is a longitudinal section showing the configuration of the sludge filtration dehydrator of this embodiment example. FIG. 2 is a plan view of the frame plate showing the shape and arrangement of the hole frame provided on the frame plate, and FIG. 3 is a layout diagram of the nozzle for ejecting pressurized air.
In addition to the same configuration as the conventional filter dehydrator 10, the sludge filter dehydrator 60 of the present embodiment is further provided with a frame plate 62 provided so as to cross the sludge chamber 14 and a container wall of the sludge chamber 14. And a pressurized air jet nozzle 64 provided.
[0021]
As shown in FIG. 2, the frame plate 62 includes circular hole frames 66 having a hole diameter larger than the outer diameter of the filter cloth cylinder 20 in at least the number of filter cloth cylinders 20 in the same arrangement as the filter cloth cylinder 20. As shown in FIG. 1, it is a plate body, and the lower part of the filter cloth cylinder 20 is penetrated.
In the present embodiment example, the frame plate 62 is obtained by punching a steel plate and providing a hole frame 66.
[0022]
As shown in FIG. 1, the pressurized air ejection nozzles 64 are provided at both an upper position and a lower position of the frame plate 62. As shown in FIG. 3, both the upper and lower ejection nozzles 64 branch from ring tubes 68A to 68D (provided that the ring tube 68C is not shown) provided over 90 ° of the container wall of the container 12. 6 pieces are attached. Pressurized air supply pipes 72A to 72D having automatic open / close valves 70A to 70D (however, automatic open / close valve 70C is not shown) are connected to the ring pipes 68A to 68D, respectively.
By opening and closing the automatic opening / closing valve 70 by sequence control or schedule control, pressurized air can be ejected simultaneously from the six ejection nozzles 64 toward the filter cloth cylinder 20 over 90 ° of the container wall. In the sequence control, for example, the automatic open / close valves 70A to 70D are sequentially opened in the order of 70A, 70B, 70C, and 70D counterclockwise for 5 seconds to 10 seconds.
[0023]
In the filtration dehydrator 60 of the present embodiment, the solid matter trapped on the filter cloth surface of the filter cloth cylinder 20 accumulates while the sludge filtration dehydration process continues, and the pressure loss gradually increases.
Therefore, when the pressure loss reaches a predetermined magnitude, the filter cloth cylinder 20 is regenerated. In the regenerative operation, the on-off valve (not shown) of the sludge supply pipe 22 is closed to stop the introduction of sludge, and the on-off valve (not shown) of the filtrate pipe 32 is closed.
Next, the vent pipe (not shown) provided at the top of the liquid collection chamber 16 is opened, and then the drain pipe (not shown) provided at the bottom of the sludge chamber 14 is opened, and the sludge in the sludge chamber 14 is opened. Is discharged.
[0024]
Subsequently, after the drain pipe and the vent pipe are closed, the pressurized air is jetted from the jet nozzle 64 of the pressurized air. At that time, the automatic opening / closing valves 70A, 70B, 70C, and 70D are sequentially opened for a predetermined time, for example, about 5 to 10 seconds and pressurized from all directions of the container wall every 90 ° of the container wall of the container 12. Air is blown onto the filter cloth cylinder 20.
The filter cloth cylinder 20 is swung or vibrated by the pressurized air, and collides with the hole frame 66 of the frame plate 62. As a result, the solid matter deposited on the filter cloth surface of the filter cloth cylinder 20 is detached from the filter cloth surface and falls to the bottom of the sludge chamber 14.
Next, the plate type on-off valve 28 is quickly opened, and the solid matter is pumped by the pressurized air in the sludge chamber 14 via the sludge discharge pipe 30.
[0025]
The amount of compressed air ejected varies depending on the number and dimensions of the filter cloth cylinders. In the filter dehydrator 60 of this embodiment, when the filter cloth cylinder 20 has a length of 1.6 m and a diameter of 50 mm, the filter cloth cylinder About 20N liter per bottle.
When the sludge was filtered and dehydrated using the filter dehydrator 60 of this embodiment and the filter cloth cylinder 20 was regenerated, the amount of sludge that could be peeled, that is, the recovered sludge amount, was about 90 liters. On the other hand, when the same pressure loss occurs when sludge is filtered and dehydrated using the conventional filter dehydrator 10 having the same specifications as the filter dehydrator 60 of the present embodiment except for the frame plate 62 and the jet nozzle 64. When the sludge was recovered by regenerating the filter cloth cylinder, the recovered sludge amount was about 59 liters.
From this experimental result, it can be evaluated that the filter dehydrator 60 of the present embodiment has a sufficiently large solid peeling effect compared to the conventional filter dehydrator 10.
[0026]
In addition, while the pressurized air is ejected from the ejection nozzle 64, the pressurized air is introduced from the pressurized air pipe 36 into the liquid collection chamber 16 and further into the filter cloth cylinder 20, as in the prior art. The filter cloth surface may be pressed to remove the solid matter deposited on the filter cloth surface.
In the above example, a conventional non-deformable filter cloth cylinder is used as the filter cloth cylinder 20, which is not an expansion / contraction filter cloth cylinder, but it is also applicable to the case where an expansion / contraction filter cloth cylinder is used. it can. When the expansion / contraction type filter cloth cylinder 40 having a length of 1.6 m and a diameter of the filter cloth cylinder when expanded is 50 mm, the amount of the pressurized air ejected is about 40 N liters per filter cloth cylinder. .
[0027]
Modification Example of Embodiment Example This modification example is a modification example of the frame plate 62 provided in the filter dehydrator 60 of the embodiment example, and FIGS. It is a schematic diagram which shows the structure of the modified example of a board.
As shown in FIG. 4A, the frame plate 80 of the first modified example is formed by combining triangular bars 82 in a triangular lattice shape to form a triangular hole frame 84.
As shown in FIG. 4B, the frame plate 86 of the second modified example is formed by combining the round bars 88 in a square lattice shape to form a square hole frame 90. Further, an octagonal hole frame 94 may be formed by passing another round bar 92 between two round bars 88 constituting the four corners of the square hole frame 90.
As shown in FIG. 4C, the frame plate 96 of the third modified example is formed by bending a band-like body into a hexagonal lattice shape and combining them to form a hexagonal hole frame 98.
[0028]
【The invention's effect】
According to the present invention, a frame plate having a hole frame that penetrates the lower portion of the filter cloth cylinder is provided in the sludge chamber, and at least one of the upper and lower sides of the frame plate is provided with a jet nozzle for pressurized air. When solid matter in the sludge accumulates on the filter cloth surface of the filter cloth cylinder and the filtration pressure loss increases, the sludge and filtrate are extracted from the sludge chamber and the collection chamber of the filter dehydrator and then added from the ejection nozzle. The compressed air is ejected intermittently or continuously in a direction crossing the filter cloth cylinder, and the filter cloth cylinder is swung or vibrated to collide with the hole frame.
As a result, the solid matter accumulated on the filter cloth surface can be reliably and almost completely detached from the filter cloth surface and dropped off by the impact and vibration effects of the filter cloth cylinder when the filter cloth cylinder collides with the hole frame. it can.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a configuration of a sludge filtration and dehydrator according to an embodiment.
FIG. 2 is a plan view of a frame plate showing the shape and arrangement of hole frames provided in the frame plate.
FIG. 3 is a layout diagram of nozzles for ejecting pressurized air.
FIGS. 4A to 4C are schematic views each showing a configuration of a modified example of the frame plate.
FIG. 5 is a schematic cross-sectional view showing the configuration of a conventional sludge filtration and dehydrator.
FIG. 6 is a longitudinal front view of an inflatable filter cloth cylinder.
7A is a cross-sectional view of a filter cloth cylinder at the time of filter dehydration, and FIG. 7B is a cross-sectional view of the filter cloth cylinder at a time of regenerative operation.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Conventional filtration dehydrator 12 Vertical container 14 Sludge chamber 16 Collection chamber 18 Separation plate 20 Filter cloth cylinder 22 Sludge supply pipe 24 Sludge inlet 26 Sludge outlet 28 Plate type on-off valve 30 Sludge discharge pipe 32 Filtrate pipe 34 Filtrate Discharge port 36 Pressurized air tube 40 One example of expansion / contraction filter cloth cylinder 42 Cylindrical filter 44 Filtrate collection tube 46 Hose-like flexible filtration sheet 48 Short cylindrical cap 50 Band 52 Small through-hole, filtrate collection Mouth 54 Projection 56 Filtrate Guide Path 58 Nut 60 Sludge Filtration Dehydrator 62 of Embodiment Example Frame Plate 64 Pressurized Air Injection Nozzle 66 Hole Frame 68 Ring Pipe 70 Automatic Open / Close Valve 72 Pressurized Air Supply Pipe 80 First Modified frame plate 82 Round bar 84 Triangular hole frame 86 Second modified frame plate 88 Round bar 90 Square hole frame 92 Another round bar 94 Octagonal hole frame 96 Third modified frame plate 98 Hexagonal hole frame

Claims (2)

The lower sludge chamber into which sludge is introduced and the upper liquid collection chamber in which the filtrate obtained by filtering sludge is collected are equipped with vertical containers partitioned by a separator, and are fixed to the separator at the upper end. The filter cloth cylinder is suspended in the sludge chamber, the solid matter in the sludge introduced into the sludge chamber is captured by the filter cloth cylinder, and the filtrate that has permeated the filter cloth cylinder is discharged outside through the collection chamber. In sludge filtration and dehydrator for filtering and dewatering sludge,
A frame size larger than the outer shape of the filter cloth cylinder, penetrating the lower part of the filter cloth cylinder, and at least the number of the hole frames that collide with the oscillating or vibrating filter cloth cylinder, A frame plate provided in the same arrangement as the arrangement of the filter cloth cylinders and provided across the sludge chamber;
Pressurized air provided on the container wall at at least one of the upper position and the lower position of the frame plate so that the compressed air is intermittently or continuously ejected in a direction intersecting the filter cloth cylinder. And a jet nozzle
A sludge filtration and dehydrator, wherein each filter cloth cylinder is passed through a hole frame. At least one of the upper position and the lower position of the frame plate, a plurality of ejection nozzles are divided into a plurality of groups, and are provided on the container wall of the sludge chamber so as to surround the filter cloth cylinder, The sludge filtration and dehydrator according to claim 1, wherein the blowing and stopping of pressurized air are controlled for each group.

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