JPH01203008A - Treatment process and device for sludge or the like - Google Patents

Abstract

PURPOSE:To treat raw liquid efficiently in a short time by repeating filter dehydration by the raw liquid's own pressure and press dehydration utilizing the pressure difference between the filter pressure and press pressure in a filter chamber of a filter press successively. CONSTITUTION:Raw liquid A prevails all over respective filter chambers by compressively transferring the raw liquid A from a first pressure supplying tank 2 into a filter chamber of a filter press 4 formed with laminated filter plates, and filter dehydration is carried out under raw liquid's own pressure. Then the pressure of pressurized fluid in a second pressure supplying tank 3 communicating for equal pressure with the first pressure supplying tank 2 is controlled lower than the filter pressure by a pressure reducing valve 5 and guided into a pressurized fluid introducing tube P6 of a filter plate, and a movable partition is expanded by lessening the loss of filter pressure to carry out press dehydration in addition to filter dehydration. Press dehydration only is carried out by supplying pressure fluid higher than the filter pressure by a pressing pump or the like through a piping P9 after a given time, and a thick cake layer is formed quickly in the filter chamber.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention provides a sludge treatment method and apparatus for producing a dehydrated cake by filtering and squeezing sludge extracted from tap water or sewage. Regarding.

(Prior art) Conventionally, as a filter press for treating sludge separated and removed from tap water and sewage, Japanese Patent Laid-Open No. 59-2096
As described in Publication No. 21, the stock solution is pressurized into one filter press and the stock solution is filtered only by the self-pressure of the stock solution (hereinafter referred to as conventional example (1)). After filtering the undiluted solution using only the self-pressure of Conventional example (2)) is known.

Conventional example (2) includes a cent feed type in which the liquid is supplied from the center of the door plate, an upper feed type in which the liquid is supplied from the top of the door plate, and a pressurized liquid supply method in which the pressurized fluid pressure is applied. There are several types, including those that act from both sides of the furnace chamber and those that act only from one side.
There is no change in the essential method of first performing filtration using self-pressure and then compressing and dehydrating using pressurized fluid.

On the other hand, for post-processing of the dehydrated cake, that is, incinerating the cake or disposing of it in a landfill, there is a social demand to reduce the amount of cake from the point of view of cost reduction. There is a growing demand for higher pressure operations. and,
This operation is carried out using a high pressure pump.

(Problem that the invention attempts to solve) The above conventional technology has the following problems.

That is, in the conventional example (1), the undiluted solution is continued to be supplied until the consumption rate of the undiluted solution becomes slow below a certain level, but when the undiluted solution is turned into a dehydrated cake (hereinafter simply referred to as cake) in the desired shape in the furnace chamber. takes a long time. Therefore, the amount of cake processed per unit time is small, and the moisture content of the cake does not decrease even though it takes time.

On the other hand, in conventional example (2), the dehydration power for the undiluted solution in the furnace chamber increases and the moisture content of the cake is reduced, but since the undiluted solution is not supplied during squeezing, the dehydration power increases in proportion to the increase in the dehydration power. Therefore, the cake thickness is not thin, and as a result, it becomes difficult to peel off the cake during the cake discharge process.

Also, since a squeezing process is provided, if the filtration process is shortened,
There is a drawback that the throughput is reduced accordingly, and there is also a problem that the power cost and the rate at which the filtration time is shortened are not much different from the conventional example (1).

In addition, when using a high-pressure pump, there is a problem that if the specification is high pressure, the discharge capacity will be small in inverse proportion to the high pressure, and in the compression process when the filtration process is completed and the supply of raw solution is stopped. , the slurry in each furnace chamber reduces its volume in response to the squeezing operation, and as a result, the void in the furnace chamber filled with the squeezing fluid increases, so that the flow rate supplied from the pump increases There is a problem in that the desired high-pressure squeezing operation is made possible by extending the time period.

This invention was devised in view of the above-mentioned circumstances, and its purpose is to improve peelability by ensuring an effective thickness of the cake so that peeling is not difficult, and to reduce the moisture content of the cake. It is an object of the present invention to provide a method for treating sludge, etc., which can shorten the cycle time by supplying the consumed amount of raw solution during squeezing, increase the throughput per unit time, and reduce power costs, as well as an apparatus therefor.

(Means for Solving the Problems) Based on the above object, the present invention firstly injects a stock solution under pressure into a filtration chamber of a filter press formed by a large number of laminated filter plates, and filters it with a furnace cloth. After dehydration and a certain period of time,
A pressure fluid whose pressure is regulated to be lower than the filtration pressure is supplied between the door plate and the movable partition wall, and the raw solution is compressed and dehydrated in conjunction with the filtration and dehydration, and then only compression and dehydration is performed at a compression pressure higher than the filtration pressure. The present invention is characterized by a method for treating sludge, etc. as described above, and secondly, as an apparatus for carrying out the above method,
A pressurized fluid introduction part is provided between the filter plate and the movable partition of the filter press, which is formed by providing a movable partition wall on at least one side of the door plate forming the furnace chamber and laminating a large number of them, and forming the furnace chamber formed by the adjacent door plate. A stock solution supply pipe connected to the pump is connected to the stock solution supply pipe, and a first pressure supply tank connected to the pressurized air supply means is connected in the middle of the stock solution supply pipe, and pressurized fluid is fed to the pressurized fluid introduction section. A second pressure supply tank communicating with the first pressure supply tank is connected to the piping, and a pressure reducing valve is disposed between the second pressure supply tank and the pressurized fluid introduction part, and The pressurized fluid piping is characterized by being provided with a blow valve for releasing pressure from the pressurized fluid.

(Function) When the undiluted solution is pumped from the first pressure supply tank into the lacrimal chamber formed by the laminated door plate, the undiluted solution is distributed throughout each furnace chamber, and filtration and dehydration are performed by the self-pressure of the undiluted solution. The pressurized fluid in the second pressure supply tank, which is in communication with the pressure supply tank and has the same pressure, is regulated to a level lower than the filtration pressure using a pressure reducing valve, and is guided to the pressure fluid introduction part of the door plate, thereby reducing the filtration pressure in the furnace chamber. As the loss decreases, the movable partition wall expands, and the undiluted solution is compressed and dehydrated in conjunction with the filtration and dehydration that involves supplying the undiluted solution.After a certain period of time, a pressure fluid higher than the filtration pressure is supplied from a compression pump, etc., and the undiluted solution is compressed. Only dewatering takes place, and a thick layer of cake quickly forms in the furnace chamber.

(Example) Hereinafter, the present invention will be explained in detail based on FIGS. 1 to 3.

Reference numeral 4 in the figure indicates a single filter press in the processing apparatus according to the present invention, and inside thereof, as shown in FIG. A large number of door plates 8 (only one pair is shown in the drawing) are arranged so that they can be opened and closed alternately, and the required number (usually 10 to 70) of filter chambers 16 are formed in the horizontal direction by the door plates 8 and 9. There is.

Both furnace plates 8 and 9 have an annular frame shape, and the furnace plate 8 is equipped with an F liquid passage 15a at the lower part, and a surface plate 11 with many liquid streaks on the outer surface is attached to both sides, and the outer peripheral edge The inner peripheral edge of the filter plate 9 is sealed with a sealing material 18a, and the outside thereof is covered with a door cloth 12a.The other filter plate 9 has a pressure fluid introduction passage 14 in the upper part and a lachrymal fluid passage 15b in the lower part. A movable partition wall (hereinafter referred to as a diaphragm) 10 having many liquid streaks on its outer surface is attached to both surfaces with a pressure fluid introduction part 13 communicating with the introduction path 14 interposed therebetween, and the outer peripheral edge and the inner peripheral edge are also covered with sealing material. 18b, and the outside thereof is covered with a furnace cloth 12b.

In each F chamber 16, the stock solution A is supplied from the stock solution supply loe 7.
is supplied from the mud supply pipe P1 via the mud supply valve V, and the lachrymal fluid that has passed through each furnace cloth 12a, 12b is fed to the lower F fluid path 1.
The P liquid is discharged from 5a and 15b to the outside of the machine via a P liquid discharge pipe P.

As shown in FIG. 1, the slurry supply pipe P1 is connected to the stock solution supply pump 1 to receive the stock solution A;
There is a reverse valve V in front of the delivery part and the filter press 40.
, , V3 are arranged to prevent the required slurry supply pressure from retreating, and the first pressure supply tank 2 is connected between the slurry supply valve section and the stock solution supply pump 1 via the stock solution communication pipe P3. has been done.

The top of the first pressure supply tank 2 is connected to an air source device (not shown) through a gas supply pipe P to supply compressed air, and a gas communication pipe equipped with a gas communication valve or the like in the middle. It is connected to the second pressure supply tank 3 by P2.

On the other hand, pressure fluid piping P connected to the second pressure supply tank 3,
is equipped with a pressurized fluid pipe and a pressure reducing valve 5 in the middle, and is connected to many pressure fluid introduction pipes P6 to the filter press 4, and a blow valve 6 is installed at its terminal end so that the pressure can be released to the atmosphere. being done. The blow valve 6 may be located anywhere as long as it can relieve the internal pressure of the pipe P3.

Note that between the pressure reducing valve 5 and the pressure fluid introduction pipe P6, a piping connected to a compression pump or a compression piping system (not shown) is branched.

Then, when the pump, etc. supplies a squeezing pressure 4 higher than the overpressure to the filter press, the squeezing pressure is applied to the pipe P
A check valve (■) is provided to prevent the pressure from leaking to the pipe P, side 3, and a check valve A constant amount of water is transferred from the water supply tank 7 to the second pressure supply tank 3 via the make-up water pipe &, and the air pressure in the first pressure supply tank 2 is In response, squeezing pressure is applied.

The water supply tank 7 receives water from the blow valve 6 when the pressure is released, so that the pressurized water can be recycled.

Figure 2 shows a case where air or other inert gas is used as the pressure fluid, but compared to Figure 1, the water supply tank 7 and the makeup water pipe P
The other points are the same except that 4 is omitted.

When treating sludge, etc. based on the above configuration, first open the valve on the sludge supply pipe Pl, and transfer the stock solution A in the first pressure supply tank 2, which has been pressurized in advance, to the stock solution in the filter press 4. Supply port 1
7 to each furnace chamber 16. Initially, the stock solution A is sufficiently distributed in each p chamber 16, the filtration action by self-pressure proceeds smoothly, and dehydration only by filtration is performed for a predetermined period of time (for example, 1/4 period of the entire filtration process). I can continue.

Thereafter, the pressurized fluid valve 5 on the pipe P3 is opened, and the pressure fluid in the tank is supplied from the second pressure supply tank 3 to the pressure fluid introduction part of the F plate 9 through the introduction pipe P6 and the introduction path 14 of the filter press. 13, the diaphragm 10 is expanded as shown by the dotted line in FIG.

In this way ((When supplying pressurized fluid to the filter press, the communication valve ■ of the gas communication pipe P2 is opened, and the pressure fluid flowing through the pipe is reduced in pressure by the pressure reducing valve 5, and the squeezing pressure is lower than the stock solution supply pressure. A range determined in advance depending on the properties and feed form of the filter press (usually uy-15kg/
crl ) The pressure is regulated to become smaller.

The squeezing process that is carried out in parallel with the filtration process may be continued from the start of squeezing to the independent squeezing process after the end of the filtration process (operation 1), but only during the squeezing process that is carried out in parallel with the filtration process. , the blow valve 6 may be operated intermittently to perform the squeezing operation continuously (operation 2).

In operation 2, by intermittent operation of the blow valve 6,
The pressure inside the pressure fluid introduction section 13 on the side of the F plate is reduced through the pressure fluid introduction pipe P6, and a negative pressure section is generated between the sludge inside the p chamber 16 and the furnace cloth 12. Creates a void inside and attracts new liquid to that area.

In addition, in operation 1, by operating so as to change the differential pressure between the squeezing pressure and the filtration pressure, a working pressure whose direction is not constant is induced in an unspecified portion of the sludge in the furnace chamber.

In the above two operations, since the squeezing pressure and the filtration pressure are not applied in the same direction, shearing force is generated in the heterogeneous parts of the sludge, and the sludge is wrapped in the sludge due to the consolidation phenomenon or bridging phenomenon that has caused the filtration action to stagnate. By changing the relative position of the sludge-bound water or internal water, the filtration action as explained by conventional filtration theory progresses, and an even greater dehydration effect can be obtained.

More specifically, the initial filtration pressure (10 kg/m ) (
As the stock solution turns into a cake from /c, the filtration pressure decreases near the innermost part 16a of the P chamber 16, which has gradually turned into a cake, due to the pressure loss that occurs in the middle of the flow path of the stock solution, and the pressure of the compressed fluid decreases. Even if the pressure is reduced in advance using the pressure reducing valve 5 so that it becomes lower than the filtration pressure [parallel compression EE (9 kg/Sakaki)],
The squeezing pressure of the pressurized fluid introduction part 13 on the part near the innermost part 16a exhibits a pressure higher than the filtration pressure exerted on the cake E, and exerts a squeezing effect on the cake E.

In operation 2, when the pressure fluid is released by opening the blow valve 6 and the compression is terminated, the diaphragm 10 is restored from the expanded state to the solid line state.
A void is created in the chamber 16, and the raw solution is supplied to the void.Then, the blow valve 6 is closed again and the squeezing process is restarted to reduce the moisture content of the cake (reduction #).
It is possible to alternately perform the replenishment of the stock solution and the amount of stock solution that can be processed.

In the above example, the pressure of the stock liquid and pressure fluid is adjusted by the interlocking relationship between the pressure supply tanks 1 and 2 provided in their respective piping, and the pressure reducing valve 5.
We have shown that this is done by depressurizing the
Alternatively, flow control means may be interposed in each of the stock solution supply pipe P1 and the pressure fluid pipe P, and these may be electrically linked.

The flow rate adjustment means includes a pressure adjustment control valve and a pump for supplying raw liquid or pressurized fluid, and is installed in the piping system.

In this way, the filtration step is shifted to the single compression step. That is, the compression pump and the like operate, and the individual compression pressure (15 kgA-IF?) is supplied to the filter press via the introduction vP6 through the pipe P.

After a certain period of time, the squeezing process ends, and after that, each process such as blowing, opening the frame, and discharging the cake is completed.
Cycle time is complete.

"Test Example" Next, Table 12 shows the results of a comparative test between the present invention and the prior art.
It is shown in Table 2. The numerical values of comparative example I in the table are based on the conventional example 1, and the numerical values of comparative example 2 are based on the conventional example 2.

Table 1 shows a comparison of the treatment steps, and the pressure rise rates at the initial stage of filtration pressure and compression pressure are the same. The implementation conditions are as follows.

Sample Raw solution concentration Filtration pressure Parallel compression Single use compressed water sludge 2B”ry!X10 Danyu 9kg/cf 15
In addition, Table 2 shows a comparison of wastewater treatment results, and the treatment rate per unit time in Table 2 is expressed as an index using the comparative example as a standard of 100. By the way, the power ratio per cycle time due to the invention at this time was 60 in the comparison example.
It was ~70%.

According to these tables, it can be seen that in the present invention, the cycle time is significantly reduced compared to the prior art, and the throughput of the stock solution is increased by 2 to 4 times.

Table 1 Table 2 Although the above example describes the case of treating clean water sludge, the present invention is not limited to this, and the present invention can be applied to dewatering of other chemical industry products and waste liquid sludge.

Furthermore, in the above example, the door panels with the diaphragm 10 provided on both sides and the door panels without the diaphragm 10 were laminated alternately.
This may be provided with diaphragms on both sides of all filter plates (one side at the end).

(Effects of the Invention) As described above, according to the present invention, p-filtration dehydration is performed only by the self-pressure of the stock solution at the beginning, and after a certain period of time, the pressure is adjusted to be slightly lower than the filtration pressure in parallel with the filtration and dehydration. Since the pressure dehydration is performed using a pressurized fluid, and the differential pressure between the filtration pressure and the compression pressure can be adjusted appropriately, the undiluted solution can be processed efficiently in a short time. A cake is formed by dynamically forming a cake by changing the differential pressure between the filtration pressure and the squeezing pressure, and by continuous supply of the raw solution during that time and subsequent squeezing dehydration at a high squeezing pressure,
It is possible to appropriately promote lowering of the moisture content and thickening of the cake, and it is possible to improve peelability when discharging the cake.

In addition, in compression dehydration at high compression pressure, the raw solution is drawn into the furnace chamber at a pressure close to the filtration pressure, so the flow rate for compression is small, and the compression pump that applies high pressure can be operated efficiently. . Moreover, by intermittently carrying out the squeezing step concurrently with the filtration step, the throughput of the stock solution is increased, while the cycle time is shortened, which is industrially beneficial as it can fully exhibit the energy saving effect.

[Brief explanation of the drawing]

1 to 3 show embodiments of the present invention, and FIG. 1 is a system diagram when a squeezing fluid washing liquid is used. FIG. 2 is a system diagram when gas is used as the squeezing fluid. FIG. 3 is a sectional view illustrating the area around chamber F in the filter press. In the figure 1... Raw solution supply pump 2... First pressure supply tank 3
...Second pressure supply tank 4...Filter press 5.
...Pressure reduction valve 6...Blow valve 10.
...Movable bulkhead 13...Pressure fluid introduction part 16
... Door room P2 - ... Gas communication pipe P3 ... Pressure fluid piping b ... Piping ■ ... Supply mud
Valve Also... Gas communication valve ■, η... Check valve A...
Undiluted solution B...Gas C...Water E...Ke - Ki

Claims (3)

[Claims] (1) The stock solution is pressurized into the filtration chamber of a filter press formed by a large number of laminated filter plates, filtered and dehydrated using a filter cloth, and after a certain period of time, filtration pressure is applied between the filter plate and the movable partition wall. A treatment for sludge, etc., characterized in that a pressure fluid whose pressure is regulated to be low is fed, the raw solution is compressed and dehydrated in conjunction with the filtration and dehydration, and then only the compression and dewatering is performed at a compression pressure higher than the filtration pressure. Method. (2) The method for treating sludge, etc. according to claim 1, characterized in that the compression dewatering performed during the filtration dehydration is performed intermittently. (3) A pressure fluid introduction part is provided between the filter plate and the movable partition of the filter press, which is formed by providing a movable partition on at least one side of the filter plate that forms the filter chamber and laminating a large number of them, and forming a pressure fluid introduction part between the filter plate and the movable partition. Connect the stock solution supply pipe connected to the pump to the filtration chamber,
A first pressure supply tank connected to the pressurized air supply means is connected to the middle of the stock solution supply pipe, and a first pressure supply tank connected to the first pressure supply tank is connected to the pipe for feeding the pressurized fluid to the pressure fluid introduction section. Two pressure supply tanks are connected, and a pressure reducing valve is disposed between the second pressure supply tank and the pressure fluid introduction section, and the pressurized fluid piping is branched downstream of the pressure reducing valve to provide a compression pump, etc. 1. An apparatus for treating sludge, etc., characterized in that the pressurized fluid piping is connected to a blow valve for releasing the pressure of the pressurized fluid.