JPH01123611A - Dehydration device for sludge - Google Patents

Abstract

PURPOSE:To carry out an efficient dehydration by dehydrating the granular sludge prepared with dehydrating assistant powder by the dehydration device consisting of a press type dehydrator and a granular sludge supplier. CONSTITUTION:The dehydration device for sludge consists of the press type dehydrator 1 and the granular sludge supplier 20. The press type dehydrator 1 consists of a pressing plate 4 which is movable vertically, a filter plate 7 fixed to an upper fixed frame, and a filter cloth which is movably spanned around the upper fixed frame 2-1. A washing unit 8 to wash the filter cloth is provided on the return side of the filter cloth 6. The granular sludge supplier 20 consists of a hopper 31 having a measuring unit, a chute 35 and a transfer box 21 the bottom of which is allowed to open and close. The transfer box 21 is so equipped as to reciprocate between the granular sludge supplier 20 and the press type dehydrator 1. Consequently, the granular sludge prepared with dehydrating assistant powder is uniformly pressed and dehydrated.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a sludge dewatering device, and more particularly to a dewatering device for dewatering sludge by squeezing sludge particles coated with a dewatering aid.

[Prior Art] Sludge is generated in large quantities during the treatment of domestic and industrial wastewater. Sludge as it is extracted from treatment facilities, such as wastewater settling tanks, typically contains more than 90% water by weight. Since sludge is usually landfilled or incinerated, it is desirable that its moisture content be as low as possible.

In particular, when incinerating the sludge, in order to incinerate it without using auxiliary fuel, the water content of the sludge should be about 60% by weight or less, preferably 50% by weight or less.

Generally, sludge is flocculated by adding an organic substance such as an inorganic flocculant such as slaked lime or iron chloride or a polymeric flocculant. The flocculated sludge is then dehydrated using a vacuum dehydrator, centrifugal dehydrator, belt press, screw press, etc. The sludge that has been dehydrated and solidified in this way is called "sludge cake." Sludge cake usually contains about 70-85% water by weight.

It has been found that even if this sludge cake is pressurized at a higher pressure in order to reduce the moisture content to 60% by weight or less in order to incinerate it without auxiliary fuel as described above, dehydration does not proceed at all. Therefore, from the past, JP-A-59-1592
99. As disclosed in various publications of JP-A-59-193795, sludge cake is granulated, and tempered sludge granules coated with highly water-permeable dry powder are compressed using a press-type dehydrator. Next, dehydrate.

A dewatering device has been proposed that reduces the moisture content of sludge cake to about 50% by weight. Also, Jikoko Sho 53-7260
, Utility Model Publication No. 61-7025 disclose details of a press type dewatering device for dewatering sludge.

- Both types of dewatering equipment perform dewatering by sealing sludge or sludge particles in a space formed by a fixed base, a movable pressure plate, and a pressure cylinder, and then squeezing the sludge. there were.

"Problems to be Solved by the Invention" However, the above-mentioned sludge dewatering apparatus had the following problems.

Japanese Patent Publication No. 59-159299. Japanese Patent Publication No. 59-193795
In the dewatering equipment described in each publication, the pressure plate descends to squeeze the water, and since the upper and lower filter cloths run together, when the pressure plate descends to squeeze the water, To,
The upper filter cloth is easily damaged due to large deformation, and the lower filter cloth travels at almost the same level as the sludge granule supply platform, so the filter cloth traveling device and the sludge granule supply device compete with each other. hand,
The structure was complicated.

Also, Jitsukō 53-7260, Jitsukō 61-7025
In the dewatering equipment described in each publication, the upper and lower filter cloths or equivalent filter elements are fixed to one pressure plate, so when cleaning this, the series of dewatering operations must be interrupted. This resulted in extremely poor work efficiency.

In addition, none of the dewatering devices has a technical philosophy of leveling the surface of the supplied sludge when feeding it to the press type dehydrator, and as a result, it is not possible to pressurize the sludge particles uniformly. , the squeezing was not done enough.

An object of the present invention is to provide a sludge dewatering device that can uniformly pressurize sludge particles to perform sufficient squeezing, and that has good working efficiency.

Means for Solving Problems] The present invention provides a sludge dewatering device comprising a press type dehydrator and a sludge particle feeder for dewatering sludge particles tempered with dehydration aid powder. The dehydrator includes a cylinder provided to pressurize upward, a pressure plate fixed to the upper end of the cylinder that can be raised and lowered, a pressure cylinder that is fitted around the outer periphery of the pressure plate and that can be lowered and lowered, and an upper part. It has a filter plate fixed to a fixed frame, a filter cloth stretched so as to rotate around the upper fixed frame, and a washing device for washing the filter cloth on the return side of the filter cloth.

The sludge particle feeder includes a hopper with a measuring device for measuring the amount of sludge particles, a chute that can be raised and lowered and has a leveling device, and a transfer box that is movable and has an opening/closing plate for opening and closing the bottom. and has.

The transfer box is configured to reciprocate between the sludge particle feeder and the press type dehydrator.

The sludge particles are sealed in the space formed by the pressure plate, pressure cylinder, and upper fixed frame of the press-type dehydrator, and the water contained in the sludge particles is removed by uniformly pressurizing and squeezing the sludge particles. It is something to do.

- The dewatered sludge cake has a microstructure as illustrated by FIGS. 12-13. -The microstructure of the dewatered sludge cake consists of fine sludge particles that are weakly bonded to each other, with small gaps or spaces between them. Adjacent gaps and spaces are connected, creating tiny channels through which water can flow. These minute waterways are called "capillaries." The bond between the sludge particles in the sludge cake is relatively weak, so when the sludge cake is stirred or kneaded, the sludge cake becomes a slurry and its capillary is destroyed, and some of the dehydrated cake becomes a slurry. Once this occurs, the capillary can no longer be regenerated and it is almost impossible to further dehydrate it, even if it is squeezed under extremely high pressure.

However, if the sludge is squeezed without destroying the microstructure, ie, without stirring or kneading, the bonding structure of the sludge particles will be deformed, narrowing the capillary. As a result, the internal water held in the capillary is squeezed out, resulting in dehydration. What is important here is that the mobility (moving speed) of the internal water held in the capillary is low, and the time required to expel it is limited by the time the expelled water passes.

This means that it is approximately proportional to the square of the capillary length. In other words, if the thickness of the sludge cake is doubled, the time required for dewatering will quadruple.

Therefore, if the sludge cake is crushed into small pieces and the sludge cake is granulated into small spheres and then compressed, dewatering can be achieved in an extremely short time.

Furthermore, in dry powder such as dry incineration ash 2 coal powder, the mobility of water is extremely high and is 103 to 104 times that in a sludge cake.

Therefore, when the sludge cake is crushed and granulated into small pieces and the surface is coated with a dehydration aid such as dry incineration ash, the internal water in the capillary of the sludge granules is absorbed into the sludge granules in a short time. It reaches the surface, from where it passes extremely quickly through the dehydration aid layer and is drained to the outside.

The dehydration aid layer does not disappear even when compressed, so
Ultimately, it acts as a drainage channel drilled into the sludge grains in the form of a mesh.

When the tempered sludge particles are compressed and dewatered using a press-type dehydrator, the sludge particles are sealed and squeezed in a space formed by a pressure plate and other fixed parts, but at this time, the surface of the sludge particles accumulated in the space is If the surface is uneven, the pressure on the pressure plate will not be uniform, and
Pressure dehydration is not performed satisfactorily. Therefore, when compressing and dewatering specially refined sludge particles using a press type dehydrator, leveling the surface of the sludge particles is a major factor in achieving sufficient dewatering.

In addition, by increasing the area to be squeezed and reducing the thickness, the squeezed water can reach the filtration element in an extremely short distance, and the water in the dehydration aid is highly mobile. In addition, the dehydration effect can be sufficiently increased by only arranging the filtration element in one part.

Here, the pressure plate of the press type dehydrator is raised and squeezed,
The filter cloth is only on the upper side and can be moved freely.

If you wash it appropriately, you can wash the filter cloth while performing a series of dehydration operations.

Work efficiency can be increased.

[Example] Embodiments of the present invention will be described based on the drawings.

Fig. 1 is a schematic diagram showing the general structure of the dewatering equipment of the present invention, Fig. 2 is an enlarged plan view of the transfer box, Fig. 3 is a side view of Fig. 2 and shows a partial cross section, and Fig. 4 is a chute. Enlarged plan view of 5th
The figure is a side sectional view of FIG. 4.

In the figure, 1 is a press type dehydrator, and 2o is a sludge particle feeder.

A press type dehydrator (hereinafter referred to as a press) 1 includes a main frame 2) a main cylinder 3. Pressure plate 4, pressure cylinder 5. It consists of the main part of the upper filter cloth 6, and pressurization is performed by pushing it up from below with the main cylinder 3.

The main frame 2 has a strong box-shaped structure including an upper fixed frame 2-1, pillars 2-2, and a base plate 2-3.

The main cylinder 3 is fixed upward to the base plate 2-3 of the main frame 2, and the pressure plate 4 is attached to the tip of the ram 3-1 of the main cylinder 3. A lower filter plate 9 is provided on the upper pressure surface of the pressure plate 4.
A lower filter cloth 10 made of stainless steel is embedded therein. In addition, a pressure cylinder 5 is fitted around the outer periphery of the pressure plate 4,
The pressure cylinder 5 includes a plurality of cylinders 8 whose one end is fixed to the main frame 2 so that they can be moved up and down independently with respect to the pressure plate 4.
Concatenate. The pressurizing cylinder 5 is moved up and down by sliding on a guide (not shown) fixed to the pillar 2-2. In this embodiment, the diameter of the press plate is 1700 nwm, and its press stroke is 400 mm at maximum, and the press stroke can be changed as desired by adjusting the stroke of the main cylinder 3.

An upper filter plate 7 is embedded in the lower surface of the upper fixed frame 2-1, and an endless upper filter is installed in the upper fixed frame 2-1 so as to slide on the lower surface of the upper filter plate 7. The cloth 6 is stretched rotatably. Then, the cleaning device 8 is distributed on the return side of the upper filter cloth 6.

A sludge particle feeder (hereinafter referred to as a feeder) 20 has a transfer box 21
The main parts are a guide rail 27, a hopper 91, a chute 35, and a drum 37.

The transfer box 21 has a substantially cylindrical shape, has a lattice-like partition plate 22 disposed inside thereof, and has four wheels 23 rotatably provided on its outer periphery. Further, an opening/closing plate 24 is slidably disposed at the bottom of the transfer box 21 so as to open and close the transferring box 21, and the opening/closing plate 24 is connected to a cylinder 25 fixed to the traveling tank 21.

The transfer box 21 is connected to a drive device (not shown) and engaged via wheels 23 with a guide rail 27 provided to connect the press 1 and the sludge particle feeder 20 described above.

A cut gate 32 is provided at the bottom of the hopper 31 to open and close it, and the hopper 31 and the cut gate 32 are mounted on a pedestal 34 via a load meter 33. cut gate 3
A chute 35 is provided below the chute 35 so as to enclose it, and further below the chute 35 is provided a drum 37 which can be raised and lowered and can be horizontally rotated. The drum 37 is raised and lowered by a well-known cam mechanism, and rotated by a chain drive, and illustration thereof is omitted. Leveling blades 38 are provided at the inner lower part of the drum 37 in three horizontal directions. When the drum 37 is lowered, its lower end and leveling blade 38 are prevented from coming into contact with the upper end of the partition plate 22 provided in the transfer box 21.
Further, the vertical distance of the drum 37 is set so that an appropriate gap is created between the lower end and the upper end of the transfer box 21 when the drum 37 is raised.

The transfer box 21 reciprocates between the center of the press 1 and the center of the feeder 20.

Next, the operation of the above configuration will be explained.

- Next, the dewatered sludge cake is granulated in a previous step of the dewatering apparatus of the present invention, and formed into sludge particles whose outer periphery is coated with a suitable dewatering aid. The formed sludge particles are temporarily stored and then sent to the feeder 20 of the dewatering apparatus. Sludge particles are put into the hopper 31 of the feeder 20, and their weight is measured by the load cell 33.
When the predetermined amount is reached, the sludge particles are stopped being added. At that time, the transfer box 21 is located directly below the hopper 31. Next, the cut gate 32 is opened and the sludge particles in the hopper 31 are removed from the chute 35. It is dropped into the transfer box 21 via the drum 37. Further, at this time, the drum 37 is lowered to its lower limit so that its lower end enters into the upper end of the transfer box 21 to prevent the sludge particles from scattering. After a predetermined amount of sludge particles have been dropped, the drum 37 is slowly rotated and raised. Then, the leveling blade 38 provided inside the drum 37
The upper surface of the sludge particles accumulated in the transfer box 21 is adjusted to be extremely flat because the upper surface of the sludge particles is adjusted to be extremely flat by rotating and leveling the sludge particles. This is the main point. When the drum 37 rises to a predetermined position, the transfer box 21 travels to the center of the press 1.

The press 1 then operates as follows in relation to the transfer box 21.

First, when the transfer box 21 starts moving toward the press 1, the pressure plate 4 and the pressure cylinder 5 are in a positional relationship as shown in FIG. That is, the upper surface of the pressure plate 4 and the upper end of the pressure cylinder 5 are set at the same level, and the distance between them and the lower surface of the opening/closing plate 24 of the transfer box 21 is set to be as small as possible.

Next, as shown in FIG. 7, the transfer box 21 moves forward toward the press 1, and the transfer box 21 pushes out the sludge cake that has been squeezed first to the left and drops it into the discharge chute (path shown). It is located directly above the pressurizing cylinder 5. Then, pull out the opening/closing plate 24 of the transfer box 21.

The bottom of the transfer box 21 is opened. Next, as shown in FIGS. 8 and 9, when the pressure plate 4 is lowered to a predetermined position, the sludge particles are accommodated in the space formed by the pressure cylinder 5 and the pressure plate 4. Here, the distance between the bottom of the transfer box 21 and the top surface of the pressure platen 4 is set to about 2 to 5 mm+, and the sludge particles are transferred to the transfer box 21.
The difference in head when transferring from to the pressure plate 4 is reduced,
Due to the presence of the lattice-like partition plate 22 arranged inside the transfer box 21, the sludge particles do not completely collapse from the state in which they were present in the transfer box 21 (that is, the state in which they were flattened by the leveling blades 38 of the drum 33). It is housed in the press 1 without any problems. After this, the transfer box 21 is retreated toward the hopper 31.

Next, as shown in FIG. 10, the pressure plate 4 of the pressure cylinder 5 is raised at the same time, and the upper end of the pressure cylinder 5 is connected to the upper fixed frame 2.
1 and the upper filter cloth 6 and the upper filter plate 7 disposed in 1.

When the pressure plate 4 is further raised in this state, the sludge particles are transferred to the upper filter cloth 6 and the upper filter plate 7 of the upper fixed frame 2-1, the pressure cylinder 5, and the pressure plate 4, as shown in FIG. Lower filter cloth 10
The space formed by the transient plate 9 is sealed and strongly compressed to squeeze out moisture. The squeezed water passes through the upper and lower filter plates and is discharged to the outside through a predetermined guide groove.

The optimal pressure and pressurization time for squeezing sludge particles are set based on data obtained in advance preliminary tests.

Then, automatic operation is performed by incorporating these compression conditions into the automatic operation program. When the compression is completed, the pressure plate 4 and the pressure cylinder 5 are lowered, and further the pressure cylinder 5 is lowered until the upper end of the pressure cylinder 5 is at the same level as the upper surface of the pressure plate 4. This is the state shown in FIG. 6 described above.

After that, repeat the process described above.

Further, when the compression is finished and the pressure plate 4 and the pressure cylinder 5 are lowered, the upper filter cloth 6 rotates by a predetermined length, and a new filter cloth that has been washed is positioned on the upper filter plate 7.

The part of the filter cloth subjected to compression rotates and goes to the return side,
It is cleaned by a cleaning device 8 installed there and prepared for the next pressing.

In this example, this dewatering device was applied to secondary dehydration to further reduce the water content of the sludge cake that has undergone primary dewatering, but it is not limited to this, and the dewatering target is appropriately adjusted. If it is possible, it can be used for primary dehydration, and it can also be applied not only to sludge but also to dehydration of product materials such as food and medicine. When sludge particles are coated with a coating agent and squeezed, dewatering is not sufficient and the work efficiency is low.However, with the present invention, the sludge particles can be pressurized uniformly, and the filter element cleaning does not interrupt the dewatering operation. Because it can be done without
Efficient dehydration work can be performed.

[Brief explanation of the drawing]

Fig. 1 is a side view schematically showing the sludge dewatering device of the present invention, Fig. 2 is a plan view of the transfer box, Fig. 3 is a side view of Fig. 2, partially in section, and Fig. 4 is a plan view of the chute. 5 is a side view of FIG. 4. Figures 6.7, 8, 9, and 10.11 are side views and partial views showing the mutual relationship between the transfer box, the press plate, and the press cylinder. FIGS. 12 and 13 are schematic diagrams illustrating the state of sludge. 1; Press type dehydrator, 3; Main cylinder, 4; Pressure plate, 5
; Pressure cylinder, 6; Upper filter cloth, 20; Sludge grain supply device, 21;
Transfer box, 22; Partition plate, 24: Opening/closing plate, 31; Hopper,
37; Drum, 38; Flattened feather Roganto Hitachi Metals, Ltd., et al. Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 11 Figure 12 Figure #13

Claims (1)

[Claims] (1) For dewatering sludge particles tempered with dehydration aid powder,
In a sludge dewatering device consisting of a press-type dehydrator and a sludge particle feeder, the press-type dewaterer includes: a) a cylinder provided to pressurize upward; and b) a liftable cylinder fixed to the upper end of the cylinder. c) a pressurizing cylinder fitted around the outer periphery of the pressurizing plate that can be raised and lowered; d) a filter plate fixed to the upper fixed frame; e) a cleaning device for cleaning the filter cloth on the return side of the filter cloth, and f) a measuring device for measuring the amount of sludge particles. g) a chute that is movable up and down and has a leveling device; and h) a transfer box that is movable and has an opening/closing plate for opening and closing the bottom, and the transfer box is equipped with a sludge particle feeder and The sludge particles are moved back and forth between the press-type dehydrators, sealing the sludge particles in the space formed by the press plate, pressurizing cylinder, and upper fixed frame of the press-type dehydrator, and squeezing the sludge particles uniformly. A sludge dewatering device that removes water contained in sludge. 2) A sludge dewatering apparatus according to claim 1, characterized in that a filter cloth and a filter plate are fixed to the pressure plate.