JP2824613B2 - Sludge treatment method of shield method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for treating sludge and circulating treated water in a shield method.

[0002]

2. Description of the Related Art Excess sludge in the shield method is usually dewatered by a filter press or a belt press. That is, as shown in FIG. 1, the earth and sand excavated by the shield machine 1 is passed through the vibrating sieve 2 by the carrier water flow,
The hydrous sediment that has passed through the relatively coarse middle and lower mesh of this sieve is supplied to the cyclone 4 through the circulation tank 3 and
The sand which is centrifuged and settled in the inside is circulated and supplied again to the upper screen of the vibrating sieve 2 and the clay silt flowing out from the upper outlet of the cyclone while leaving the sand is sent to the adjusting tank 5. The main part of the clay silt is returned to the shield machine 1 from above, and the other clay silt is temporarily stored in the excess mud water tank 6, and further added with a flocculant and the like, and dewatered by a filter press 7 or a belt press and solid-liquid. Each step of performing separation (separation into water and cake 8) is performed. On the other hand, the vibrated sieve 2 blocks and the discharged earth and sand 9 is carried out by a transport vehicle or the like. It should be noted that if all the clay silt is returned to the shield machine, it is obvious that the amount of clay in the circulating water rapidly increases, which is disadvantageous.

[0003] However, a dehydrator such as a filter press has a large equipment and is extremely expensive in terms of processing capacity, and replacement of consumables such as filter cloth is troublesome.

[0004]

The object of the present invention is to discharge all solids that can be separated from muddy water from a vibrating sieve without using a filter press or the like having the above-mentioned problems.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a wastewater containing earth and sand from a shield machine, which is passed through a vibrating sieve and classified into stones which are blocked by the mesh and hydrous soil which passes through the mesh.
The passed hydrous soil is supplied to a cyclone, and the sand that is centrifuged and settled in the cyclone is circulated and supplied again to the upper fine mesh in the vibrating sieve, and the clay silt that flows out of the upper outlet of the cyclone while leaving the sand. To the regulating tank, return some of the clay silt from the regulating tank to the shield machine, and store the remaining clay silt in the excess mud tank in preparation for post-treatment such as solid-liquid separation. In the sludge treatment method of the shield method including,

A drum screen type sludge having a cylindrical screen main body for passing the contents from the inlet end to the outlet end while dewatering the contents by the mesh during rotation, and a driving mechanism for rotating the cylindrical screen main body. Using a dewatering device, the clay silt recovered from the excess sludge tank is supplied to the drum screen type sludge dewatering device, and the concentrate discharged from the outlet end of the device is formed on the upper mesh in the vibrating sieve. It is supplied on a sand deposit layer, and is further dewatered by this vibrating sieve.

[0007] Preferably, a driving mechanism of the drum screen type sludge dewatering device applies vibration in addition to rotation of the screen main body.

[0008]

In the present invention, a drum screen type sludge dewatering apparatus used in place of a filter press or the like rotates a cylindrical screen main body by a driving mechanism including a roller for supporting rails provided around the screen in a contact transmission relationship. By driving, preferably providing an evenly uneven or concave arrangement on the outer peripheral surface of the roller and also applying vibration to the screen main body, dehydration and flocking of the received sludge (in this case, clay silt) can be drastically promoted. Things. Therefore, when the flocs discharged from the sludge dewatering device are supplied again to the uppermost portion (sand deposit layer) of the vibrating sieve, they remain in the state of agglomerates and are blocked by the sand filtration layer,
Further, dehydration is further promoted, and is eventually discarded from the vibrating sieve together with the sedimentary sand layer. Therefore, the silt does not pass through the sieve and does not increase the silt concentration of circulating water.

[0009]

FIG. 2 is a diagram showing the configuration of a sludge treatment flow channel of the shield method according to the present invention. The components from the shield machine through a vibrating sieve and a cyclone to a sludge tank are the same as those of the conventional flow channel configuration. And each of these elements
The same reference numerals as those of the corresponding elements denote the same elements, and a description thereof will not be repeated.
In the present invention, the sludge from the excess sludge tank 6 is sent to a drum screen type sludge dewatering machine 10 without depending on the dewatering and pressing means such as a filter press as in the prior art.
Then, the dewatered sludge is returned to the sand accumulation layer formed on the uppermost fine mesh 11 of the vibrating sieve 2. As described above, this drum screen type sludge dewatering machine has a novel structure with inventive features per se,
Circular rails 13a and 13b are provided around the entrance end and the exit end of the cylindrical screen main body 12, and these circular rails 13 are provided.
a and 13b are supported and driven by rollers 14a and 14b in a contact transmission relationship.

As shown in FIG. 3, these rollers, indicated generally at 14, are supported at two locations for each orbiting rail, indicated generally at 13, and rotate about a fixed rotary shaft 15 A plurality of recesses 15 are formed at regular intervals on the outer peripheral surface of these rollers 14 at least on the outlet side of the sludge dewatering machine 10 for rotating and guiding the cylindrical screen main body 12. Therefore, when the cylindrical screen main body 12 is rotationally driven by any of the rollers,
The roller 14 with the concave portion that rotates together with the main body 12 has a contact surface with the rail 13 that repeats irregularities sequentially.
2 will be vibrated. Accordingly, in FIG. 2, the sludge supplied from the inlet side (right end) of the drum screen type sludge dewatering machine 10 reaches the outlet side while being effectively dewatered by the rotation and vibration of the screen, and is discharged. The spiral internal structure 16 shown in the drum screen type sludge dewatering machine 10 in FIG. 2 is a spiral fold for propelling the sludge received in the screen to the outlet side according to the rotation of the drum. In particular, roller 1
In the case where the concave arrangement in 4 is provided only on the roller 14b on the outlet side, the vibration of the drum screen gradually increases from the inlet side to the outlet side, and corresponds to the progress of dehydration and agglomeration of the supplied sludge. By vibrating this to the extent that it is not crushed, dewatering and flocking are effectively promoted. Further, even when all the rollers 14 support and drive the screen main body with a smooth surface having no concave arrangement (when no vibration is applied), it is possible to promote dehydration and flocking without hindrance to the implementation of the present invention. is there.

In the flow path configuration of the present invention using the drum screen type sludge dewatering machine 10 as described above, first, the earth and sand excavated by the shield machine 1 is placed on a middle mesh (for example, mesh 10 mm) of the vibrating sieve 2. Supplied, here 10m
m or more stones are blocked, and the pebbles and water that have passed therethrough are passed through the lower mesh (for example, a mesh of 5 mm). The hydrated sediment passing therethrough is supplied to the cyclone 4 through the circulation tank 3, centrifuged in the cyclone, and the sedimented sand is returned to the upper end fine mesh (for example, mesh 0.5) in the vibrating sieve 2.
０．７0.7 mm). The clay silt separated from the sand and discharged from the upper outlet of the cyclone 4 is sent to the adjusting tank 5, and some of the clay silt is returned to the shield machine 1 from the adjusting tank 5, and the remaining clay silt is left as is. It is sent to the muddy water tank 6.

In this way, the clay silt discharged from the excess sludge tank 6 is supplied to the sludge dewatering machine 10 together with the coagulant. As described above, the dehydration and flocking of the clay silt are promoted, and the clay silt is concentrated to a water content of 88 to 92% or more. The floc concentrated in this way is fed onto the sand deposit layer formed on the uppermost fine net 11 in the vibrating sieve 2 described above. This layer of sand constitutes an effective filtration layer for flocs. Therefore, the supplied floc is kept in a state of a condensed mass and is prevented by the filter layer made of sand, and dehydration is further promoted. These dewatered flocs are eventually discarded from the vibrating sieve 2 together with the sand deposit layer, and eventually become excavated earth and sand pits 9a including the concentrate of clay silt, which are carried out by a transport vehicle or the like.

[0013]

As described above, according to the present invention, excavated earth and sand can be effectively separated and discarded without using a filter press or the like which is economically expensive and troublesome for maintenance.
That is, it is expected that the use of a drum screen type sludge dewatering machine instead of a filter press will dramatically reduce the equipment cost and reduce the operating cost to several tenths or less.

[Brief description of the drawings]

FIG. 1 is a flowchart of conventional sludge treatment in a shield method.

FIG. 2 is a flowchart of the sludge treatment of the present invention in the shield method.

FIG. 3 is a schematic cross-sectional view of a drum screen type sludge dewatering apparatus used in the flow channel configuration of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shield machine 2 Vibrating sieve 3 Circulation tank 4 Cyclone 5 Conditioning tank 6 Surplus water tank 7 Filter press 9 Earth and sand 10 Sludge dewatering machine

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C02F 11/00-11/20 E21D 9/06

Claims (2)

(57) [Claims] 1. A wastewater containing earth and sand from a shield machine is passed through a vibrating sieve, classified into stones blocked by a mesh and hydrated sand passing through the mesh, and the passed hydrated sand is supplied to a cyclone. The sand which is centrifuged and settled in the circulating sieve is again circulated and supplied to the upper mesh screen in the vibrating sieve, and the clay silt flowing out from the upper outlet of the cyclone while leaving the sand is sent to the adjusting tank, and the clay silt is discharged from the adjusting tank. A method for treating sludge of a shield method, comprising returning each part to the shield machine and storing the remaining clay silt in a residual sludge tank in preparation for a post-treatment such as solid-liquid separation. A cylindrical screen body for passing the contents from the inlet end to the outlet end while dewatering the contents by the mesh,
Using a drum screen type sludge dewatering device having a drive mechanism for rotating the cylindrical screen main body, supplying clay silt recovered from the excess sludge tank to the drum screen type sludge dewatering device, and the outlet of this device A sludge treatment method according to a shield method, wherein the concentrate discharged from the end is supplied onto a sand sedimentary layer formed on an upper mesh screen of the vibrating sieve, and further dewatered by the vibrating sieve. 2. The method according to claim 1, wherein the drive mechanism of the drum screen type sludge dewatering device applies vibration in addition to rotation of the screen main body.