JP2914490B2 - Sludge dewatering method and dewatering equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION TECHNICAL FIELD OF THE INVENTION

[0001] The present invention relates to a method for dewatering sludge generated in civil engineering construction work, dredging work and the like, and an improvement of a dewatering treatment apparatus therefor. For example, a dredged sludge having a high water content is reused for embankment in other works. For the purpose, type 3 construction generated soil (cohesive soil and its equivalent, where ordinary workability is ensured; cone index qc = 4 ^kgf / cm ² or more) or type 4 construction generated soil (cohesive soil and And a dewatering treatment device used in the dewatering treatment method, which is simple and inexpensive so as to obtain a dewatering treatment method (excluding the type 3 construction waste soil).

[0002]

2. Description of the Related Art In civil engineering construction work, dredging work, etc., in particular, dredged soil with a high water content in dredging work is pumped up to a vast muddy ground and treated by civil dehydration methods such as solar drying. Even if it takes about one month to one year, it is only possible to dehydrate to the type 4 construction soil (cone index is generally 2 or more), or it is impossible to dehydrate to the same soil, so it is unavoidable. Instead, they were mixed with sand and other good-quality soil, improved and transported. Recently, dewatering methods using a filter press, a belt press, a centrifugal dehydrator, etc., have become widespread as mechanical forced dewatering methods at civil engineering construction sites and the like. A forced dewatering method using a filter press that can be dewatered to a specific ratio is widely used. In the case of forced dewatering using a filter press, the dewatering of bottom mud in rivers and lakes and the dredged mud of sludge can be dewatered up to about the type 4 construction soil, but the type 3 construction soil In order to increase the dehydration, the dehydration time becomes extremely long, and at the same time, the amount of dehydration decreases significantly. Therefore, usually 5
For a standard filter press for dewatering by pressure of 7 ^kgf / cm ^2, and sets the high-pressure type filter press dewatering with high 40 ^kgf / cm ² pressure, the diaphragm to inflate at a high pressure fluid pressurizing chamber, filtration A filter press that pressed the dewatered cake in the room further was developed,
Both of them are not popular in the field of civil engineering and construction because the structure of the device is complicated, the handling is difficult, and the device is generally expensive. The present invention has been made by paying attention to the above-mentioned prior art, and in particular, the above-mentioned high-pressure filter press, wherein the diaphragm to be expanded with a high-pressure fluid is set in a pressurized chamber to further squeeze the dewatered cake. An object of the present invention is to provide a dehydration processing means having a simple structure and capable of efficiently obtaining a dewatered cake having a low water content, which is made by focusing on a filter press or the like.

[0003]

SUMMARY OF THE INVENTION In order to achieve the above objects, the present invention firstly provides a filter plate for a filter press body.
A filter frame made of a rigid body and provided on both sides of the filter plate
The metal frame faces the filter plate around the filter frame.
To form a discontinuous part in the opposite part of the metal frame,
Sliding between the facing surfaces of the metal frame in a direction parallel to the metal frame.
The existing slide stopper and the slide
Place the stopper between the opposing discontinuities of the metal frame and filter plate
In front of the sludge prior to pressurized dewatering of the sludge
Move the slide stopper forward so that it is located between
A filter chamber with a certain thickness is formed to enable the injection of sludge.
After pressurized dewatering of sludge injected into
Move the slide stopper back so that
It means that for squeezing and dewatering, the second in the filter plate and濾枠constituting the filter press body, to form the filter plates of a rigid, form a濾枠an elastic body, the outer circumference of the濾枠A metal frame attached to the filter plate is arranged opposite to the metal frame, a discontinuous portion is formed at an opposing portion of the metal frame, and slidable in a direction parallel to the metal frame between opposing surfaces of the metal frame. In addition to the slide stopper, the slide stopper is placed between the opposite discontinuous parts of the metal frame and supported by the filter plate. A sludge filter chamber is formed to enable press-fitting of sludge, and after pressurized dehydration of sludge pressed into the filter chamber is completed, the slide stopper is moved back to the original position to enable press-drying of the sludge. That we have configured .

[0004]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The first to ninth aspects of the present invention will be described with reference to FIGS. 1 to 6. The dehydrating apparatus and the dehydrating method will be described in this order. The schematic configuration of the sludge dewatering treatment apparatus according to claims 6 to 9 of the present invention includes a filter press body 1, a filter plate 2 and a filter frame 3, which are constituent members thereof, and a filter press body 1 and a filter frame 3. A metal frame 4, a slide stopper 5 disposed between opposing surfaces of the metal frame, a compression spring 7 involved in the operation of the stopper, and a slide means 9 for the stopper.

The filter press body 1 is based on a well-known structure composed of a filter plate 2, a filter frame 3 and a filter cloth 11,
It is different from the well-known filter press body that the material of the filter frame 3 is an elastic body (for example, neoprene rubber). The purpose of forming the filter frame 3 from an elastic body is to make a large number of filter chambers 6 formed by pressing the filter plate 2 into filter chambers 6 having a constant thickness.

As shown in FIG. 2, the filter press body 1 is of a single-sided double-sided filtration type in which the filter plate 2 is of a single type, and the elastic filter frame 3 is arranged and fixed at opposing portions on both peripheral edges of the filter plate 2 ( The filter plate 2 which is configured
The filter cloth 11 is disposed in a space formed by the filter frame 3 and the filter frame 3. As shown in FIGS. 2 and 3, a plurality of filtrate discharge passages 13 are formed and arranged in a T-shape in a front view at the lower portion of the filter plate 2 so as to discharge the filtrate.

The metal frame 4 includes a filter frame 3, a slide stopper 5
A member involved in forming the filter chamber 6 having a constant thickness together with the like.
When the filter plate 2 is pressed, the elastic filter frame 3 is compressed while mutually opposing and fixed to the peripheral edges of both sides of the filter plate 2, specifically, the outer peripheral portion of the filter frame 3 attached to the filter plate 2. When approaching, the slide stopper 5 comes into contact with and stops on both surfaces of the access rod 5-3, and a large number of filter chambers having a constant thickness are formed. Metal frame 4 to filter plate 2
When fixing to the opposing portions of the peripheral edges of both sides, the discontinuous portion 10 is formed to oppose, and the filter plate 2 is pressed to squeeze the sludge in the filter chamber 6 (more specifically, in the filter cloth 11) after pressurized dehydration. When dehydrating, the slide rod 5 of the slide stopper 5 stopped at the original position.
The discontinuous portion 10 is advanced to the point 3 so that the entering / leaving rod enters the discontinuous portion 10 so that the above-mentioned compression dewatering is performed without any trouble. Then
The discontinuous portion 10 of the metal frame 4 does not necessarily need to be formed near the corner of the filter frame 3 as shown in the drawing, but is not formed due to the relative positional relationship with the slide rod 5-3 of the slide stopper 5. An arrangement portion of the continuous portion 10 is determined, and the in-and-out rod 5-3 is arranged between the discontinuous portions 10 facing each other.

A slide stopper 5 is provided between a slide rod 5-1 slidable in a direction parallel to the metal frame 4 and a spring receiving portion 8 of the slide rod and a rod support portion 5-2 of the filter plate 2. Compression spring 7 and the sliding rod 5-
1 comprises a slide means 9 to be pressed against, and an in / out rod 5-3 provided at the other end of the slide rod 5-1 to enter and exit between the opposed metal frames 4. The slide rod 5-1 of the slide stopper 5 is supported on the filter plate 2 by the rod support portion 5-2 near the metal frame away from the metal frame 4, and the support structure is such that the rod support projecting from the filter plate 2 is provided. The metal frame 4 is slidable in a direction parallel to the metal frame 4.

The slide rod 5-3 of the slide stopper 5 is
This member is involved in forming the filter chamber 6 having a constant thickness. The member is protruded toward the filter frame 3 at the other end of the slide rod 5-1, and when the slide rod 5-1 moves forward, FIG. Slide to the position shown by the imaginary line in FIG. 4 and enter between the adjacent metal frames 4 (between the metal frames 4 on the upper surface and between the metal frames 4 on the lower surface in the filter frame 3 in FIGS. 3 and 4) and slide. When the rod 5-1 moves back, it returns to the original position shown by the solid line in FIG. The formation part of the spring receiving part 8 formed on the slide rod 5-1 is not limited to one end shown in the drawing, and a compression spring 7 is interposed between the slide receiving part 8 and the rod support part 5-2 formed on the filter plate 2. As long as one end of the sliding rod 5-1 can always be pressed against the sliding means 9, the sliding rod 5-1 can be mounted.
In the middle part in the length direction, the rod support part 5-2 and the in-and-out rod 5-
It can be between 3.

The slide means 9 is constituted by a cam mechanism.
The cam mechanism is connected to a hydraulic cylinder 9-2 by a cam shaft 9-1 supported by a bearing, and is configured to rotate 90 ° by reciprocation of the cylinder. One end of a slide rod 5-1 is a compression spring. It is always in pressure contact with the 7 bullets. When the sliding means 9 is rotated by 90 °, the sliding rod 5 of the slide stopper 5 is opposed to the elastic force of the compression spring 7.
3 slides from the solid line position to the imaginary line position in FIGS. 3 and 4, and when the slide means 9 rotates in the reverse direction by 90 °, the compression spring 7 rebounds and returns to the solid line position (original position) in FIG.

Next, a dehydration method (claims 1 to 5) using the dehydration apparatus having the above configuration will be described. 1 and 2
As shown in the drawing, a number of filter plates 2 are arranged side by side, and prior to pressurization and dewatering of sludge, the hydraulic cylinder 9-2 of the slide means 9 is advanced, and the cam mechanism is rotated by 90 ° to slide the slide rod 5 of the slide stopper 5. -1 is made to move forward, and the slide-in / out rod 5-3 is slid from the solid line position shown in FIGS. 3 and 4 to the virtual line position.

In this state, the pressing mechanism 12 (for example, a hydraulic jack or a hydraulic cylinder) for the filter press body 1 is operated to press a large number of the filter plates 2 arranged in parallel.
Then, since the filter frame 3 is formed of an elastic body and the metal frame 4 is formed of a rigid body (metal), the dimension between the opposing surfaces of the filter plate 2 is l ₃ as shown in FIG. The length dimension is l ₂ , the thickness dimension of the slide rod 5-3 of the slide stopper 5 is l ₁ , and the metal frame 4
If the l ₄ dimensions between the opposing surfaces of the and out rod 5-3,
The filter plate 2 is pressed by 2 l ₄ (the opposing filter plates 2 are pressed by 2 l _{4 in a} direction approaching each other), and l ₁ +
A large number of filter chambers 6 each having a constant thickness of 2 l ₂ are formed, and the sludge can be injected.

The formation of a large number of filter chambers 6 having a constant thickness is an important requirement for forming a uniform dewatered cake under the same dewatering conditions, and significantly improves the dewatering effect. Then, the sludge is injected into the large number of filter chambers 6 having a constant thickness. A well-known sludge pump is used as the injection means, and the injection pressure is adjusted by controlling the rotation speed of the centrifugal pump for injection by an inverter. did.

The above press-fit pressure is 0.5 ^kgf / cm ² → 3 ^kgf
/ Cm ² → 7 ^kgf / cm ² , but this pressurization timing measures the amount of filtrate, and performs the pressurizing operation when the amount of filtrate falls below a certain ratio in each constant-pressure filtration. . If this pressure timing is compared to a familiar example, when a wet towel containing a sufficient amount of water is squeezed, a large amount of water is initially drained, but if the initial squeezing force is maintained, the amount of drainage will eventually decrease. (Refer to point a in FIG. 5.) Then, the water is squeezed again with force, and the amount of drainage temporarily increases, but the amount of drainage decreases unless the squeezing force is increased. (Refer to the point b in FIG. 5.) In this case, the squeezing is performed with a stronger force. Therefore, the timing at which the throttle force is increased in anticipation of the time when the amount of drainage decreases is referred to as the pressurization timing.

When the pressurizing operation is performed at the above-described pressurizing timing, it is very effective in shortening the dewatering time and preventing an accident in which sludge is ejected from the filter plate 2. In the experiment, when the injection pressure was 7 ^kgf / cm ² and the filtrate volume became lower than a certain ratio, the injection centrifugal pump was stopped, and the pressure dehydration operation was terminated. Next, when the operation of the pressing mechanism 12 for the filter press body 1 that has pressed the filter plate 2 is stopped, the filter plate 2 returns by the above-mentioned 2l ₄ (the pressing amount) and returns to the original position.
(The approaching opposing filter plates 2 move away from each other by 2l ₄
Just go back. )

Next, the cam mechanism of the slide means 9 is rotated in the reverse direction by 90 °, and the slide rod 5-3 of the slide stopper 5 is returned to the original position by the rebound of the compression spring 7. (In FIGS. 3 and 4, the access rod 5-3 returns from the virtual line position to the solid line position.)
Since the original position of the in-and-out rod 5-3 is a position between the opposed discontinuous portions 10 of the metal frame 4 as shown in FIGS.
This is a position where the access rod 5-3 does not function as a stopper. (Refer to the partially enlarged view of FIG. 4.) Here, when the pressing mechanism 12 for the filter press body 1 is advanced, the liquid between the sludge particles is squeezed by an external pressure, so that the dewatered cake having an extremely low water content is squeezed and dewatered. Can be made with (See the enlarged view.) In the experiment, the compression pressure for compression dehydration was 1
The pressing force of the pressing mechanism 12 was controlled to be 4 ^kgf / cm ² .

The metal frame 4 cooperates with the slide rod 5-3 of the slide stopper 5 to prevent the dewatering cake from being formed when the filter chamber 6 is clogged due to insufficient pressure dehydration in the preceding stage. When the filter frame 3 is crushed and dewatered without being sufficiently formed, the filter frame 3 is crushed beyond its elastic limit to prevent the filter frame 3 from becoming difficult to recover or to be destroyed. And a function of preventing the filter frame 3 from swelling outward during compression dehydration to prevent the filter frame 3 from being damaged. As mentioned above, if the sludge is dehydrated in order of pressure dehydration → compression dehydration, it is possible to remove the type 3 construction soil (corn index of 4 ^kgf) even for hardly dehydrated sludge such as bottom mud such as rivers and lakes and sludge. / Cm ² ), which makes it possible to dewater in a short period of time, and can be used as a highly useful sludge dewatering means.

The thickness (width) of the filter chamber 6 is set to 20 mm.
In order to examine the press dewatering effect between the case where the pressure is set to 32 mm and the case where the pressure is set to 32 mm, for example, the standard pressure dehydration without the press dehydration is performed for 40 minutes, and the pressure dehydration is performed when the pressure is depressed.
And pressing and dewatering for 10 minutes, and dehydration is performed.
As shown in the figure, it can be seen that the value of the water content of the dewatered cake is smaller in the compressed dewatering and the value of the cone index of the cake is larger, and in particular, the thickness (width) of the filter chamber 6 is 32 mm and the value of 20 mm is larger. A remarkable effect was exhibited as compared with the case, and it was found that the corn index was 10.1 and 2.6 with and without the pressing operation, which was about 3.9 times different. From this, for a single throughput, the number of filter chambers 6 can be reduced as the thickness of the filter chamber 6 increases, and the filter press body 1 can be reduced in size. In addition, the present invention is advantageous in providing a low-cost sludge dewatering treatment means.

[0019]

[Table 1]

However, if the thickness of the filter chamber 6 is made infinitely thick, the pressurized dewatering time will be prolonged. Therefore, it is considered that the thickness of the filter chamber 6 is limited to about 50 mm. Therefore, the filter chamber 6
Is preferably about 25 to 50 mm.

Thus, in the filter press 1 used in the present invention, the cement-based solidifying material is added to and mixed with the sludge before the dewatering of the sludge, and the functions of the press dewatering in this case and the press dewatering in the case of no addition are described below. The effects were examined. Table 2 and FIG.
As shown in the figure, when 11% of the solidified material was added, the amount of the filtrate increased, the value of the water content of the dehydrated cake became smaller, and the cone index (1 day) was 16 minutes under pressure and 4 minutes under pressure. It increases by 9 times to 0.8 ^kgf / cm ^{2 in} the case of no addition and 7.2 ^kgf / cm ^{2 in} the case of the addition of the solidifying material. It has been found that it has a great dehydration effect.

The solidified material has the advantage of not only improving the dewatering effect and improving the strength of the dewatered cake immediately after dewatering, but also enabling the long-term strength development by the original solidifying action. Here, the solidification material addition amount of 11% described above is fixed at 11% addition to the dry soil amount, and therefore does not change even if the amount of sludge to be treated increases or decreases.

[0023]

[Table 2]

[Brief description of the drawings]

FIG. 1 is a partially cutaway plan view schematically showing the treatment apparatus used in the dehydration treatment method of the present invention.

FIG. 2 is a sectional view taken along line (2)-(2) of FIG.

FIG. 3 is an enlarged sectional view taken along line (3)-(3) of FIG. 2;

FIG. 4 is a left side view of FIG. 3 and a partially enlarged side view at the time of pressing and dewatering.

FIG. 5 is an explanatory diagram of pressurization timing for sludge injection.

FIG. 6 is a graph showing the effect of adding a solidifying material on the amount of filtrate.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Filter press main body 2 ... Filter plate 3 ... Filter frame 4 ... Metal frame 5 ... Slide stopper 5-1 ... Slide rod 5-2 ... Rod support part 5-3 ... Entry / exit rod 6 ... Filter chamber 7 ... Compression spring 8 ... Spring receiving part 9: slide means (cam mechanism) 10: discontinuous part

──────────────────────────────────────────────────続 き Continuation of the front page (51) Int.Cl. ⁶ Identification code FI C02F 11/12 B01D 25/15 (72) Inventor Ryuichi Kawanishi 4-1-1 Komyobashi, Chuo-ku, Osaka-shi, Osaka Toyo Construction Co., Ltd. (72) Inventor Kenji Morita 4-1-1 Komyobashi, Chuo-ku, Osaka-shi, Osaka Toyo Construction Co., Ltd. (72) Inventor Satoshi Okazaki 12-14, Kita 6-Jo Nishi, Chuo-ku, Sapporo, Hokkaido Fuji Engineering Incorporated (58) Field surveyed (Int.Cl. ⁶ , DB name) B01D 25/12 B01D 25/172

Claims (9)

(57) [Claims] 1. The filter plate of a filter press body is formed in a rigid body.
The filter frame provided on both sides of the filter plate
And attach the metal frame to the filter plate around the filter frame.
A discontinuous portion is formed at a portion facing the metal frame,
Between the facing surfaces of
Place the ride stopper and slide stop
Pars are placed between the opposing discontinuities of the metal frame and supported by the filter plate
Prior to pressurized dewatering of the sludge
Move the slide stopper forward so that it is located between
A sludge filter chamber is formed to enable sludge press-fitting and press-fit into the filter chamber.
After pressurized dewatering of waste sludge, it returns to the original position
Back the slide stopper to squeeze out the filtration chamber
Dewatering method of sludge, characterized by water. 2. The filter chamber formed during pressurized dewatering of sludge has a thickness of 2.5 to 5.0 cm.
The sludge dewatering method described. 3. The method for dewatering sludge according to claim 1, wherein the step shifts from pressure dehydration to compression dehydration when the filtrate flow rate during pressure dehydration falls below a certain ratio. 4. The sludge dewatering method according to claim 1, wherein the press-fitting pressure is increased when the flow rate of the filtrate during the pressure dehydration falls below a certain ratio. 5. The sludge dewatering method according to claim 1, wherein a solidifying material is added to the sludge before being fed to the filter press body. 6. A filter plate and a filter frame constituting a filter press body, wherein the filter plate is formed of a rigid body and the filter frame is formed of an elastic body, and is attached to the outer periphery of the filter frame to the filter plate. Along with disposing the metal frames facing each other, a discontinuous portion is formed at the opposing portion of the metal frames, and a slide stopper slidable in a direction parallel to the metal frame is disposed between the opposing surfaces of the metal frames. The slide-in / out rod of the slide stopper is arranged between the discontinuous parts of the metal frame opposite to each other and supported by the filter plate, and the slide stopper moves forward before pressurized dewatering of sludge to form a filter chamber with a constant thickness. To enable the press-fitting of the sludge, and after the pressurized dehydration of the sludge pressed into the filter chamber, the slide stopper is moved back to the original position to enable the press-drying of the sludge. Sludge dewatering equipment. 7. The sludge dewatering apparatus according to claim 5, wherein the elastic body forming the filter frame is rubber. 8. A metal frame attached to a filter plate is disposed on an outer periphery of a filter frame constituting a filter press body, and a discontinuous portion is formed at an opposing portion of the metal frame. A slide rod is arranged in the direction parallel to the metal frame in the vicinity of the metal frame remote from the filter frame and supported by the filter plate. A compression spring is provided between a spring receiving portion formed on the slide rod and a rod support portion of the filter plate. , One end of the slide rod is pressed against the slide means so that the slide rod can be slid in a direction parallel to the metal frame, and the other end of the slide rod enters and exits between the metal frames. A rod is protruded and arranged between the opposing discontinuous portions of the metal frame, and the inflow and outgoing rod is inserted between the metal frames prior to pressurized dewatering of the sludge, so that a filter chamber having a constant thickness can be formed. ,
6. The sludge dewatering treatment apparatus according to claim 5, wherein a slide stopper is configured to retreat the entrance / exit rod from between the metal frames and to enable the dewatering of the sludge in the filtration chamber by pressing. 9. The sludge dewatering apparatus according to claim 6, wherein the slide means for sliding the slide stopper in a direction parallel to the metal frame is a cam mechanism.