JPH07308657A - Excavation waste earth regeneration plant - Google Patents

Abstract

PURPOSE:To recycle excavation waste earth by a method in which the waste earth is separated in sequence by more than one separator into specified types of earth and sand respectively, and muddy water from the final separation means is returned to the initial separation means or to a muddy water agitation means with the separation residue of the initial separation means to maintain the amount of raw water. CONSTITUTION:Excavated earth fed into a hopper is treated by the oscillation sieve of the first separator 1 to separate earth and sand A with a particle size of a specified value or more. The separated earth and sand A is transported by a conveyer 18. Earth and sand with a particle size of a specified value or less is fed into a raw water agitation tank 2 containing muddy water; the mixture, after being agitated, is sent to the second separation means 4 by a pump 21 to separate earth and sand B with a specified particle size. Muddy water containing earth and sand with a particle size of a specified value or less is fed into the third separator 5 to separate earth and sand C with the third specified particle size. Muddy water generated in the third separator 5 is fed into a muddy water adjustment agitation tank 7 from an outlet 5c and, after being agitated, returned to the first agitation tank 2 or the first separator 1 through a return passage 34 to maintain the amount of raw water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plant for treating and reclaiming excavated waste soil (residual soil or sludge-like matter) produced by various works.

[0002]

2. Description of the Related Art The conventional cast-in-place pile construction method, which is generally used in the past, is to form a pile directly in the ground by drilling it on site. There are the following three types of construction method. The earth drill method is a method of rotating a cylindrical bucket to dig down, pulling up the bucket and discharging the soil each time soil accumulates in the bucket. The all-casing method involves dropping a Hammaglab bucket to grab the earth and sand, and insert a casing tube into the hole to prevent the earth and sand from falling. The reverse construction method sucks up earth and sand along with muddy water.

Regarding these cast-in-place pile construction methods, at present, excavated waste soil is treated as sludge industrial waste.
For example, as a method for dewatering and solidifying sludge, addition of a cement-based solidifying material, addition of a lime-based solidifying material, temporary sun drying, and the like are performed. In such a treatment, the reusable sand content is also discarded, and the strong alkalinity greatly affects the environment.

In the excavation waste soil treatment for such cast-in-place pile construction as well, as with the problem of general waste treatment, even if the amount of waste is increasing year by year, there are facilities for disposal and disposal. There are few places, which has become a major social and environmental problem.

However, the present condition of excavated soil treatment in cast-in-place pile construction is as described above, and recycling of excavated waste soil has been delayed considerably. Particularly, in the earth drill method, since the excavated waste soil is in the form of mud having a high concentration, it is difficult to treat it, and at present, effective recycling has not been attempted.

An object of the present invention is to provide a plant for recycling excavated waste soil generated in various works including cast-in-place pile work such as earth drilling method.

[0007]

As shown in the drawings of the first embodiment (FIGS. 1 to 4) or the drawings of the second embodiment (FIGS. 5 and 6) described later, the excavation according to the first invention is performed. In the waste soil treatment and regeneration plant, as the primary treatment equipment E ₁ , the first separating device 1, the first stirring device 2, the second separating device 4, the second stirring device 6, the third separating device 5, and the third stirring device are used. 7 and 7. In the first separating apparatus 1, the excavated waste soil is separated into a first sediment A having a predetermined value or more and a second sediment having a predetermined value or less. In the first stirring means 2, the second earth and sand from the first separating device 1 having a predetermined value or less is stirred with mud water to be raw water. In the second separating device 4, the raw water from the first stirring means 2 is a third earth and sand B and C having a predetermined value smaller than the second earth and sand and a predetermined value smaller than the third earth and sand B and C. It is designed to separate into muddy water containing the fourth earth and sand.
The second stirring means 6 stirs the muddy water containing the fourth earth and sand from the second separating device 4.
In the third separation device 5, the muddy water from the second stirring means 6 is used as a fifth earth and sand finer than the fourth earth and sand and a sixth earth and sand finer than the fifth earth and sand. It is designed to be returned to the second separating device 4 after being separated into muddy water containing. The third stirring means 7 is configured to stir the muddy water containing the sixth earth and sand from the third separating device 5. Then, the return passage 3 for returning the muddy water from the third stirring means 7 to at least one of the first stirring means 2 and the first separating device 1.
4 are provided.

The excavated waste soil treatment and regeneration plant according to the second aspect of the invention is provided with the fourth separating devices 9 and 59 in addition to the above-mentioned first aspect of the invention. In the fourth separators 9 and 59, the muddy water from the third stirring means 7 is separated into the sixth earth and sand D having a predetermined value or less and the other separated water. The separated water from the fourth separators 9, 59 is supplied to the third stirring means 7 as described above.
And return paths 56, 58 for returning to at least one of the second separating device 4 and the first separating device 1.

[0009]

In the first aspect of the present invention, the first separating device 1 produces the earth and sand A, and the second separating device 4 and the third separating device 5 produce the earth and sand B and C. Further, the muddy water from the third separating device 5 is returned to the first stirring device 2 and the first separating device 1 by the return passage 34 via the third stirring device 7, and the amount of raw water is maintained.

In the second invention, in addition to the first invention, the soil D is produced by the fourth separating devices 9 and 59.
Then, the separated water is finally produced from the fourth separators 9 and 59 and returned from the return paths 56 and 58, and the concentration adjusting dilution water of the third stirring means 7 and the first separator 1 or. It is reused as washing water for the second separation device 4.

That is, for the excavated waste soil having a high concentration in a mud state and having a property that it is difficult to separate it into an effective substance, the dehydrated separation water for recycling is added and mixed to form a muddy water state. The major feature of this method is that it produces various types of earth and sand from this muddy water, and it aims to make effective use of excavated soil.

[0012]

First Embodiment First, an excavated waste soil treatment and regeneration plant according to a first embodiment of the present invention will be described with reference to FIGS. 1 to 4.

The excavated waste soil treatment and regeneration plant shown in FIG. 1 can be roughly divided into a primary treatment facility E ₁ and a secondary treatment facility E ₂ . In the primary treatment facility E ₁ , a low head screen 1 as a first separating device, a raw water stirring tank 2 as a first stirring means, a double screen 4 as a second separating device, and a cyclone 5 as a third separating device. A sand collector 3 comprising a sieve / mud water stirring tank 6 as second stirring means, a mud water adjusting stirring tank 7 as third stirring means, and a mud water stirring tank 8
And are installed. In the secondary treatment facility E ₂ , a screw decanter 9 as a fourth separator, a dilution water tank 10, a PAC tank 11, a fresh water tank 12, a coagulant dissolving tank 13, and a coagulant storage tank 14 are installed. Has been done.

In the low head screen 1,
As shown in FIGS. 1 and 3, a sieve 16 vibrated by a vibrator 15 is provided, and excavated soil put in a hopper 17 as a supply port is separated by the vibrating sieve 16. And 2
5 mm or more of earth and sand A (gravel and clay) are removed, and they are carried out by the belt conveyor 18 from the exit 1a. On the other hand, the earth and sand of 25 mm or less (gravel and clay), the exit 1b
Is sent to the raw water agitation tank 2 containing muddy water and agitated by the blade agitator 19. Water level float switch 20
Is for detecting the amount of raw water in the raw water agitation tank 2, and is an example of means for measuring the water level to detect the amount of raw water.

As shown in FIGS. 1 and 2, the double screen 4 of the sand collector 3 is provided with an upper stage sieve 23 and a lower stage sieve 24 which are vibrated by a vibrating machine 22, and the inside of the raw water stirring tank 2 is provided. The raw water is supplied to the supply port 4a by the first pump 21 based on the detection of the water level rise of the water level float switch 20
From the lower sieve 24. The earth and sand B of 2.5 to 3.0 mm or more separated by this lower stage sieve 24 is carried out by the belt conveyor 25 from the outlet 4b. On the other hand, 2.5
The muddy water containing earth and sand of mm or less is stored in the sieve muddy water stirring tank 6 of the sand collector 3 from the outlet 4c and is stirred by the blade stirring machine 26. The water level float switch 27 is for detecting the amount of muddy water in the sieve-muddy water stirring tank 6. The overflow mud water in the sieve mud water stirring tank 6 is returned to the raw water stirring tank 2 through the overflow pipe 28.

The muddy water in the sieve muddy water stirring tank 6 is detected by the second pump 29 based on the detection of the water level rise by the water level float switch 27.
The cyclone 5 of the sand collector 3 from the supply port 5a
Sent to. By the centrifugal action of this cyclone 5,
Muddy water containing 2.5 mm or less of earth and sand is 0.074 to 2.5
It is separated into 1 mm of earth and sand and 0.074 mm or less of earth and sand. The earth and sand C of 0.074 to 2.5 mm is sent from the outlet 5b to the upper screen 23 of the double screen 4 through the supply port 4d, and is vibrated and dewatered by the earth and sand accumulated on the screen 23 to the belt conveyor from the exit 4d. It is carried out by 25. The muddy water dropped from the upper sieve 23 onto the lower sieve 24 is treated in the same manner as described above. On the other hand, 0.074 mm
The muddy water containing the following clay is sent from the outlet 5c of the cyclone 5 to the muddy water adjusting stirring tank 7 as overwater.

In the adjusted muddy water stirring tank 7, the muddy water from the cyclone 5 is stored and stirred by the blade stirring machine 31. The muddy water in the adjusting stirring tank 7 is circulated by the third pump 32 through the pycnometer 32 as a concentration detecting means,
The specific gravity is measured by the specific gravity meter 33 to detect the concentration. When the water level of the raw water in the raw water stirring tank 2 drops,
The water level float switch 20 detects the decrease in the water level.
The fourth pump 34a is driven based on the detection signal, and the muddy water in the adjustment stirring tank 7 is supplied to the raw water stirring tank 2 through the return pipe 34. Therefore, the amount of raw water in the raw water stirring tank 2 becomes stable. The water level float switch 35 is for detecting the amount of muddy water in the adjusting stirring tank 7, and is an example of means for measuring the water level and detecting the amount of muddy water. When the water level float switch 35 detects that the water level of the muddy water in the adjusting stirring tank 7 is above a certain level, the fifth pump 3 is detected based on the detection signal.
6 is driven, and excess mud water in the adjusting stirring tank 7 is sent to the stored mud water stirring tank 8.

In this muddy water agitation tank 8, the muddy water is agitated by the blade agitator 37. When the sixth pump 38 is driven based on the detection of the water level drop of the water level float switch 35 in the adjusting stirring tank 7, the muddy water in the stored mud water stirring tank 8 is returned to the adjusting stirring tank 7. The water level float switch 39 is for detecting the amount of muddy water in the muddy water stirring tank 8. When the water level float switch 39 detects that the water level of the muddy water in the stored muddy water stirring tank 8 has exceeded a certain level, the seventh pump 4
0 is driven, and the muddy water in the muddy water stirring tank 8 is supplied to the screw decanter 9 through the screw stirrer 41 in the secondary treatment facility E ₂ .

As described above, when the water level float switch 39 detects that the muddy water level in the muddy water agitation tank 8 is below a certain level, the fresh water in the fresh water tank 12 is removed from the fresh water tank 12 in the secondary treatment facility E ₂ . The eighth pump 42 feeds the flocculant dissolving tank 13, and various organic polymer flocculants and fresh water are stirred by a blade stirrer 43 to form a solution having a concentration of 0.1 to 0.2%. This solution is sent to the coagulant storage tank 14 by the ninth pump 44 and stirred by the blade stirrer 45. Further, this solution is sent to the screw stirrer 41 by the tenth pump 46. On the other hand, polyaluminum chloride as a kind of inorganic coagulant in the PAC tank 11 is sent to the screw stirrer 41 by the eleventh pump 47. The amount of polyaluminum chloride added is 10 to 20 k.
g / sst. The screw stirrer 41 mixes the muddy water from the mud water stirring tank 8 with the solution from the flocculant storage tank 14 and the polyaluminum chloride from the PAC tank 11 and supplies the mixture to the screw decanter 9. This flocculant solution and polyaluminum chloride are for helping the separation of mud water.

As shown in FIG. 4, in the screw decanter 9, a rotary cylinder 49 is provided in a casing 48, and a screw conveyor 50 is provided in the rotary cylinder 49 to rotate the screw conveyor 50. The rotary cylinder 49 rotates around the central axis 50a by the differential gear mechanism 50b.
Is designed to rotate relative to the screw conveyor 50. The mixed liquid from the screw stirrer 41 becomes a floc shape in which each particle in the muddy water is bonded, and the supply port 51
To the rotation center shaft 50a of the screw conveyor 50.
It passes through the inside and flows out between the outer circumference of the conveyor 50 and the inner circumference of the rotary cylinder 49. Then, it is separated into dehydrated earth and sand and separated water by the centrifugal action, and the dehydrated earth and sand D is carried out by the belt conveyor 53 through the outlet 52, and the separated water is sent to the dilution water tank 10 through the outlet 54 and re-formed. It is stored as water for use.

When the specific gravity of the muddy water detected by the hydrometer 33 in the adjusting stirring tank 7 rises above a certain level,
The pump 55 is driven and the water in the dilution water tank 10 is returned to the return pipe 56.
And is sent to the adjusting stirring tank 7 through which the muddy water therein is diluted. Further, the water in the dilution water tank 10 is sent by the thirteenth pump 57 through the return pipe 58 to the upper screen 23 of the double screen 4 of the sand collector 3 and also to the screen 16 of the low head screen 1. Used as wash shower water.

The excavated waste soil treatment and regeneration plant according to the first embodiment has the following features. (A) Primary treatment facility E for excavated waste soil (remaining soil or sludge-like material) generated by cast-in-place pile construction using the earth drill method, etc.
_{In 1} , the separation is performed by the following process.

Firstly, by the low head screen 1, 2
Produces earth and sand A of 5 mm or more. Secondly, sand collector 3 consisting of double screen 4 and cyclone 5.
Depending on the soil B of 2.5-3.0 mm or more and 0.074
Produces ~ 2.5 mm of earth and sand C.

(B) Further, in the secondary treatment facility E ₂ , the muddy water discharged from the primary treatment facility E ₁ is separated by the following treatment. Thirdly, the screw decanter 9 produces earth and sand D of 0.074 mm or less.

(C) After all the mud water discharged from the primary treatment facility E ₁ is treated in the secondary treatment facility E ₂ , all the produced water discharged from the screw decanter 9 is effectively used by the following treatment.

First, the muddy water in the adjusting stirring tank 7 in the primary treatment facility E ₁ is reused as dilution water for adjusting the specific gravity. Secondly, it is reused as washing shower water for the double screen 4 and the low head screen 1 of the sand collector 3 in the primary treatment facility E ₁ .

As shown in (a), (b) and (c) above, all the excavated waste soil, which has been difficult to reclaim in the past, is positively utilized as the above four types of recycled earth and sand A, B, C, D.
It can be effectively used for various purposes depending on their properties.

Also, the water separated from the excavated waste soil is not discharged in consideration of the environment and is effectively utilized in the facility. Since it is desirable not to discharge this water at all, it is managed so that excess water does not come out.

[0029]

Second Embodiment Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, instead of the screw decanter 9 in the primary treatment facility E ₂ of the first embodiment, a filter press 59 is used as a fourth separating device.
Are using. In connection with this, in the secondary treatment facility E _{2 of} the first embodiment, the fresh water tank 12, the flocculant dissolving tank 13, the flocculant storage tank 14, and the screw agitator 41 are omitted, and the primary treatment of the first embodiment is performed. A slurry stirring tank 60 is added to the facility E ₁ .

When the water level float switch 39 detects that the mud water level in the mud water agitation tank 8 in the primary treatment facility E ₁ is above a certain level, the seventh pump 40 is driven and the mud water is agitated from the mud water agitation tank 8. While being sent to the slurry stirring tank 60, the eleventh pump 47 is driven in the PAC tank 11 to send polyaluminum chloride to the slurry stirring tank 60,
They are agitated by the blade agitator 61. The water level float switch 62 is for detecting the amount of slurry in the slurry stirring tank 60.

As shown in the principle of FIG. 6, in this filter press 59, a fixed holding plate 64 and a movable holding plate 6 are provided.
5, the filter cloths 67 are pressed against each other, and both filter cloths 67 are pressed against each other and held between the filter boards 66 adjacent to each other, and a filter chamber 68 surrounded by the filter cloths 67 is formed. To be done. When the water level float switch 62 detects that the water level of the slurry has risen above a certain level in the slurry stirring tank 60, the fourteenth pump 63 is driven and the fixed holding plate 64 is provided.
The slurry is supplied from the slurry stirring tank 60 to the side slurry pressure inlet 69. The slurry is pressed into the filter chambers 68 through the communication holes 70 of the filter plates 66, and the water in the filter chambers 68 is discharged from the filtrate outlet 71 through the filter cloths 67. The dehydrated cake K remains in each filter chamber 68. When the movable holding plate 65 is separated from the fixed holding plate 64, each of the filter plates 66 is moved to the movable holding plate 65 side one by one. At this time, the filter plates 66 are separated from each other, and the dehydrated cake K falls on the belt conveyor 72. The dehydrated cake K is sent from the belt conveyor 72 to the crusher 73. After that, the earth and sand D is carried out by the belt conveyor 74. On the other hand, the water discharged from the filtrate outlet 71 falls on the water receiving tray 75 and is then sent to the dilution water tank 10.

Other functions are similar to those of the first embodiment. Also in this second embodiment, as in the case of the first embodiment, the excavated waste soil has four types of recycled earth and sand A, B,
The water is effectively used as C and D, and the water produced by the production is not discharged and is effectively used in the facility.

Considering the above-mentioned embodiments, the following concept can be understood. (A) The first separating device (low head screen 1) according to claim 1 has a sieve 16, a supply port (hopper 17) for excavated soil placed on the sieve 16 and a predetermined value that does not pass through the sieve 16. Exit 1a from which the above first sediment A is carried out
And an outlet 1b through which the second earth and sand of a predetermined value or less passing through the sieve 16 is carried out. Here, the sieve 16 refers to one that can be classified into earth and sand above a predetermined value and earth and sand below a predetermined value depending on whether or not the excavated soil passes through a large number of small holes, and it is not always necessary to apply vibration.

(B) The first stirring means in claim 1 is a raw water stirring tank 2 having a stirring function (blade stirrer 19).
Is. (C) The second separation device (double screen 4 of the sand collector 3) in claim 1 has a sieve (upper stage sieve 23 and lower stage sieve 24), and the raw water from the raw water stirring tank 2 of (b) above is sieved. 24, a supply port 4a that leads to above 24, an outlet 4b that carries out the sediment B (which is finer than the second sediment) above a predetermined value that does not pass through the sieve 24, and a fourth soil below the predetermined value that passes through the sieve 24. An outlet 4c for carrying out muddy water containing (finer than the third sediment B) is provided. The sieves 23 and 24 referred to here have the same meaning as the sieve (a).

(D) The second stirring means in claim 1 is a sieve-mud water stirring tank 6 having a stirring function (blade stirrer 26). (E) The third separation device in claim 1 is a centrifugal separator (cyclone 5), and the sieve mud water stirring tank 6 of (d) above.
5a for supplying muddy water from the outlet and an outlet 5 for discharging the fifth earth and sand (smaller than the fourth earth and sand) above a predetermined value
b, and an outlet 5c for discharging muddy water containing sixth earth and sand (finer than the fifth earth and sand) having a predetermined value or less. Second separation device (double screen 4) described in (c) above
Is provided with a supply port 4d for receiving the earth and sand from the outlet 5b and placing it on the sieve 23, and an outlet 4e for discharging the earth and sand C that does not pass through the sieve 23. The second separator (double screen 4) includes an upper screen 23 and a lower screen 24. The earth and sand from the outlet 5b is guided to the upper stage sieve 23 from the supply port 4d. The earth and sand C that does not pass through the upper sieve 23 is carried out from the outlet 4e. Here, the cyclone 5 is a device that separates and collects by utilizing the centrifugal force generated when the muddy water entering from the supply port 5a swirls, and when the muddy water swirls around the central discharge pipe toward the outlet 5b, the mass A large amount of earth and sand above a predetermined value is discharged to the outer periphery of the swirling flow by centrifugal force and collects in the outlet 5b, and muddy water containing earth and sand below a predetermined value is carried out from the outlet 5c of the central discharge pipe.

(F) The third stirring means in claim 1 is a muddy water adjusting stirring tank 7 having a stirring function (blade stirrer 31). (G) The fourth separator according to claim 2 is a centrifuge (screw decanter 9) or a pressure filter (filter press 59), and a supply port 51 into which the muddy water from the adjusting and stirring tank 7 of (f) enters. , 69 and the outlets 52, 72 for discharging the sixth earth and sand D of a predetermined value or less, and the outlets 54, 75 for discharging the finally remaining separated water.

(H) The above-mentioned centrifugal separator is a general term for those that utilize centrifugal force to separate muddy water. Among them, the (g) screw decanter 9 is a so-called cylindrical decanter, in which the muddy water supplied from the supply port 51 to the rotary cylinder 49 is concentrated and dehydrated in the rotary cylinder 49, and the separated water is discharged from the outlet 5.
4, the soil D concentrated on the inner peripheral surface of the rotary cylinder 49 is forcibly carried to the outlet 52 by the screw conveyor 50.

(I) The pressure filter is a general term for a device that pressurizes and filters mud water. Among them, the above (g)
In the filter press 59 of the above, a plurality of filter plates 66 are provided between the two plates 64 and 65 which are relatively movable and are close to each other.
Are arranged side by side along the relative movement direction, both filter cloths 67 are provided between the respective filter plates 66, and both filter cloths 67 between the respective filter plates 66 pressed against each other between the both plates 64, 65 are held. A filter chamber 68 surrounded by both filter cloths 67 is formed between the filter plates 66, and when slurry is pressed into each filter chamber 68 from a slurry pressure inlet 69 leading to each filter chamber 68, Is discharged from the filtrate outlet 71 through the filter cloth 67, and the dehydrated cake K remaining in each filter chamber 68 is discharged as the filter plates 66 are separated.

(E) The separated water discharged from the fourth separating device (g) is sent to the dilution water tank 10. Each of the return paths 56, 58 in claim 2 is connected to the dilution water tank 10. (L) An agitation tank (muddy water agitation tank 8 or slurry agitation tank 60) for agitating the muddy water from the adjusting agitation tank 7 of the above (F) is provided, and the muddy water from this agitation tank is subjected to the fourth separation of the above (G). Supply to the device.

(2) The concentration detecting means 33 is provided in the muddy water adjusting and stirring tank 7 of (f) above, and the concentration detecting means 3 is provided.
When the measured concentration of 3 becomes higher than the set concentration, a control means for driving and controlling the pump 55 is provided so as to send the separated water from the dilution water tank 10 of the above () to the adjusting stirring tank 7 through the return pipe 56. There is. Therefore, the required amount of the final separated water can be sent to automatically keep the concentration of the muddy water in the adjusting stirring tank 7 constant, and the muddy water can be reliably separated in the (4) fourth separator.

(W) In the raw water stirring tank 2 of (B) above, the raw water amount detecting means 20 is provided, and the raw water amount detecting means 2 is provided.
When the measured raw water amount of 0 becomes larger than the set raw water amount,
A control means for driving and controlling the pump 34a is provided so as to send the muddy water from the muddy water adjusting and stirring tank 7 (f) to the raw water stirring tank 2 through the return pipe 34. Therefore, the amount of raw water can be automatically kept constant, and the raw water can be smoothly supplied to the second separation device (c).

(F) The coagulant from the muddy water coagulant supply means is supplied to the fourth separating device of the above (g). In this embodiment, the PAC tank 11 is used as the muddy water coagulant supply means.
And the coagulant storage tank 14 or the like.

[0043]

According to the excavation waste soil treatment and regeneration plant of the present invention, excavation waste soil which has been difficult to regenerate in the past is separated and dehydrated to produce recycled earth and sand A, B, C and D, and various It can be effectively used for the purpose. Moreover, the separated water from the excavated soil can be circulated and used effectively in the facility without being discharged.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing an excavated waste soil treatment and regeneration plant according to a first embodiment.

FIG. 2 is an enlarged view of the sand collector shown in FIG.

3 is an enlarged view of the low head screen shown in FIG. 1. FIG.

FIG. 4 is an enlarged view of the screw decanter shown in FIG.

FIG. 5 is a circuit diagram showing an excavated waste soil treatment and regeneration plant according to a second embodiment.

FIG. 6 is an enlarged view of the filter press shown in FIG.

[Explanation of symbols]

1 ... Low head screen as first separating device, 2 ...
Raw water stirring tank as first stirring means, 3 ... sand collector, 4 ... double screen as second separating device, 5 ...
Cyclone as third separating device, 6 ... Screen mud water stirring tank as second stirring means, 7 ... Mud water adjusting stirring tank as third stirring means, 8 ... Mud water stirring tank, 9 ... Screw as fourth separating device Decanter, 10 ... Dilution water tank, 11 ... PAC
Tank, 14 ... Flocculant storage tank, 16 ... Sieve, 23 ... Upper sieve, 2
4 ... Lower sieve, 34 ... Return pipe as return passage, 56 ... Return pipe as return passage, 58 ... Return pipe as return passage, 59
... a filter press as a fourth separating device, 60 ... a slurry stirring tank, A to D ... earth and sand.

Claims (2)

[Claims] 1. A first earth and sand (A) having a predetermined amount of excavated waste soil or more.
And a first separating device (1) for separating into a second sediment having a predetermined value or less, and a first stirring from which a second sediment having a predetermined value or less from the first separating device (1) is stirred with mud water to be raw water. Means (2)
And the raw water from the first stirring means (2) is a third earth and sand (B, C) finer than the second earth and sand and a predetermined value finer than the third earth and sand (B, C). A second separator (4) for separating into muddy water containing the following fourth earth and sand, second stirring means (6) for stirring the muddy water containing the fourth earth and sand from this second separator (4), and (2) The muddy water from the stirring means (6) is separated into the muddy water containing the fifth earth and sand, which is finer than the fourth earth and sand and has a predetermined value or more, and the sixth earth and sand, which is finer than the fifth earth and sand and has a predetermined value and less than this. A third separating device (5) for returning the fifth earth and sand to the second separating device (4); and a third stirring means (7) for stirring the muddy water containing the sixth earth and sand from the third separating device (5). The muddy water from the third stirring means (7) is supplied to any one of the first stirring means (2) and the first separating device (1). Drilling waste soil treatment recycling plant, characterized in that a path back to return to (34). 2. The first stirring means (7) according to claim 1.
The fourth separator (9, 59) for separating the muddy water from the above into the sixth earth and sand (D) having a predetermined value or less and the other separated water, and the separated water from the fourth separator (9, 59) Claim 1
A return path (56, 58) for returning to at least one of the third stirring means (7), the second separation device (4) and the first separation device (1) described in 1. Excavation waste soil treatment and regeneration plant.