JP3800375B2 - Mud disposal method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention mainly relates to a method for treating mud soil dredged from the bottom of a sea, lake, or river.
[0002]
[Prior art]
When water pollution of the sea, lakes, or rivers is progressing, it is extremely important from the viewpoint of maintaining the ecosystem to prevent such water pollution from progressing and restore a good environment.
[0003]
The cause of water pollution is the inflow of organic substances from the outside and the elution of nutrients from the bottom mud. Therefore, it is effective to remove and remove the bottom mud to improve the water quality of the lake. Is.
[0004]
However, dredged mud has a high water content and low strength, so it is difficult to dispose of it as it is or to reuse it. Therefore, it is essential to increase the strength by adding a solidifying material to the dredged clay.
[0005]
On the other hand, dredged mud generally has a considerable capacity, and it is not easy to secure a disposal site. Therefore, another challenge is to reduce the volume of dredged mud.
[0006]
[Problems to be solved by the invention]
However, in order to improve the strength of dredged mud with a high water content, a large amount of solidifying material is required, so the cost of the solidifying material is high, and adding such a large amount of solidifying material further increases the capacity of dredged mud soil. Increasingly, there was a problem that a vast land had to be secured to handle it.
[0007]
The present invention has been made in consideration of the above-described circumstances, and an object of the present invention is to provide a method for treating dredged mud that can achieve volume reduction of dredged mud and saving of solidified material.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the method for treating mud according to the present invention, as described in claim 1, adds a slow-hardening solidifying material to the mud and stirs to form mixed mud, and the mixed mud is filled in a water-permeable bag. Then, a method for treating mud that is allowed to stand for a predetermined period of time, wherein the slow-hardening solidified material is composed of slow-hardening cement.
Further, according to the method for treating mud according to the present invention, as described in claim 2, a slow-hardening solidifying material is added to the mud and stirred to form mixed mud, and the mixed mud is filled in a permeable bag body for a predetermined period. A method for treating mud to be left, wherein the slow-hardening solidifying material is composed of a super-retarding agent and cement.
[0009]
In the mud treatment method according to the present invention, a predetermined load is loaded on the water-permeable bag filled with the mixed mud during the standing.
[0010]
In the mud treatment method according to the present invention, the water-permeable bag filled with the mixed mud is stacked during the standing.
[0011]
Moreover, the processing method of the mud according to the present invention is to reuse the water-permeable bag body after the leaving period has passed as a banking material, a bank body material or a landfill material.
[0012]
In the method for treating mud according to the present invention, first, a slow-hardening solidifying material is added to the mud and stirred to obtain mixed mud. Next, the mixed mud is filled in a water-permeable bag and left for a predetermined period.
[0013]
In this way, the water contained in the mud is squeezed out from the inside of the water-permeable bag body by compaction, capillary action, etc., and when the mud is solidified, the water content of the mud reaches a certain level. descend.
[0014]
The mud includes mud mud drowned from the bottom of the sea, lakes, or rivers, as well as mud produced by the mud shield method, the underground continuous wall method, and the like.
[0015]
For example, a slow-hardening cement can be used as the slow-hardening solidified material, and if it is formulated so that strength develops especially after several days, sufficient dehydrating action can be expected during that time. Specifically, for example, an additive called a so-called super-retarding agent that is used to integrate old and new concrete without producing a cold joint in the concrete joint portion may be used.
[0016]
In addition, since the water content of the mud is reduced by dehydration, the amount of the slow-hardening solidifying material added can be smaller than in the conventional case.
[0017]
The material of the water-permeable bag is not limited as long as it can withstand the weight of the mud. For example, a woven fabric or a non-woven fabric can be used.
[0018]
It is arbitrary how the permeable bag body is arranged during the standing, and even if it is left alone, it can be dehydrated to some extent by the weight of the mixed mud, but a predetermined load is applied to the permeable bag body. Is loaded, the above-mentioned dehydration action is promoted, and the water content of the mixed mud filled in the water-permeable bag can be reduced more efficiently.
[0019]
How to load a water-permeable bag filled with mixed mud is arbitrary. For example, a method of placing soil on a water-permeable bag arranged so as not to overlap is conceivable. If the water-permeable bags are stacked in several stages, a sufficient load can be loaded on the water-permeable bags even in a relatively narrow space.
[0020]
It is arbitrary how to dispose of the permeable bag after it has been left unattended, and it may be transported to a predetermined waste disposal site and disposed of as it is. There is little risk of the substance leaching out, and it also has a predetermined strength. If this is reused as embankment material, embankment material or landfill material, it will not be necessary to secure a waste disposal site and resources will be re-used. Since it is also used, it contributes greatly to environmental protection.
[0021]
The term “leaving” as used in the present invention mainly refers to standing, but also includes operations such as applying vibration and swinging.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a mud treatment method according to the present invention will be described below with reference to the accompanying drawings. Note that components that are substantially the same as those of the prior art are assigned the same reference numerals, and descriptions thereof are omitted.
[0023]
FIG. 1 is a flowchart showing a procedure of a mud treatment method according to the present embodiment, and FIG. 2 is a layout diagram of each facility.
[0024]
As can be seen from these drawings, in the mud processing method according to the present embodiment, the mud 1 is first dredged from the bottom of the sea, lake, or river (step 101). For dredging, for example, a high concentration dredger should be used.
[0025]
Next, the dredged mud 1 is once put into the settling basin 3 via the pressure feed pipe 2, and then the dredged mud 4 is sucked by the sand pump 5 and put into the stirring tank 6 (step 102).
[0026]
Next, a slow-hardening cement 7 as a slow-hardening solidifying material is added to the stirring tank 6 and stirred to form a mixed mud 8 (step 103). When the slow-hardening cement 7 is blended so that strength develops after about 2 to 7 days, a sufficient dehydrating action can be expected during that time. Specifically, for example, an additive called a so-called super-retarding agent that is used to integrate old and new concrete without producing a cold joint in the concrete joint portion may be used.
[0027]
Next, the mixed mud 8 in the agitation tank 6 is sent to the place where the water permeable bag 11 is disposed via the sand pump 9 and the mud pipe 10, and the mixed mud is filled into the water permeable bag 11, (Step 104).
[0028]
FIG. 3 shows a state in which the water-permeable bag bodies 11 are stacked in two stages and are sequentially filled from those arranged in the lower stage.
[0029]
The water permeable bag 11 is preferably composed of a woven fabric or a non-woven fabric having a tensile strength that does not break even when the mixed mud 8 is filled, for example, a tensile strength of about 50 kgf / cm ² . In addition, what has a water permeability of a 10 ^<-2 > cm / s order, for example here is preferable.
[0030]
When the water-permeable bags 11 filled with the mixed mud 8 are left in a two-stage stack, the water contained in the dredged mud 4 leaches out from the inside of the water-permeable bags, When the dredged mud 4 is solidified by the slow-hardening cement 7, the water content of the dredged mud is lowered to a certain level.
[0031]
In addition, about the leachate from the water-permeable bag 11, after collecting this in the drainage groove 12, if it contains a large amount of silt, after adding a flocculant and performing a cohesive settlement process, It only has to be discharged into the river.
[0032]
Next, the water-permeable bag body 11 that has been left untreated is carried out and reused as a banking material, a bank body material, or a landfill material (step 105).
[0033]
As described above, according to the method for treating mud according to the present embodiment, the slow-hardening cement 7 is added to the dredged mud 4 and stirred to form the mixed mud 8, which is filled in the permeable bag 11 and left to stand. Since it did in this way, before the dredged mud 4 solidifies with the slow-hardening cement 7, the water | moisture content contained in this mud oozes out from the water-permeable bag body 11. FIG. That is, the dredged clay 4 having a high water content is dehydrated to a certain level before the hydration reaction by the slow-hardening cement 7 is started, and thus the dredged mud is in a state where the volume is reduced to a certain level. The strength of 4 can be improved. Further, since the water content of the dredged clay 4 is reduced by dehydration, the required amount of the slow-hardening cement 7 can be smaller than in the conventional case.
[0034]
FIG. 4 is an experiment for examining how the water content ratio is reduced by filling the permeable bag with dredged mud soil. The water content ratio, which was 400% at the beginning, decreases to 100% after 60 days. You can see how they are doing.
[0035]
If a method of adding solidification material after performing mechanical dewatering such as a filter press is adopted, volume reduction of dredged mud and saving of solidified material can be achieved as in this embodiment. In view of the fact that the equipment for carrying out the process is large, and that additional installation and maintenance costs are required, the dredged mud disposal method according to the present embodiment is extremely inexpensive, and the dredged mud volume reduction and solidification material. It can be said that this is a useful method that can simultaneously achieve savings.
[0036]
Moreover, according to this embodiment, since the water-permeable bag body 11 filled with the mixed mud 8 was stacked during standing, the dehydration action was promoted, and the water content of the dredged mud 4 was reduced more efficiently. In addition, even in a relatively narrow space, a sufficient load can be loaded on the water permeable bag 11 to efficiently perform dehydration. This is a significant area reduction compared to the area required for sun drying.
[0037]
Moreover, according to this embodiment, there is little possibility that a chemical substance elutes from the inside of the water-permeable bag 11 which has been dehydrated and solidified, and has a predetermined strength. Or by reusing it as landfill material, it becomes unnecessary to secure a waste disposal site and reuse of resources, which greatly contributes to environmental protection.
[0038]
In the present embodiment, the water-permeable bag body 11 that has been dehydrated and solidified after the leaving period has passed is taken out and reused as a levee body material or the like. It may be disposed of. In such a configuration, the volume of dredged mud is reduced to a predetermined level, so that the required capacity at the waste disposal site is small. In addition, if the water-permeable bag 11 is left without being carried out and is greened by applying embankment or the like on it, a park with moderate undulations can be created.
[0039]
【The invention's effect】
As described above, according to the method for treating mud according to the present invention, moisture contained in the mud is leached from the water-permeable bag before the mud is solidified by the slow-hardening solidifying material. In other words, mud with a high water content ratio is dewatered to a certain level before the solidification reaction with the slow-hardening solidification material starts, and the strength of the mud is improved with a certain volume reduction. Is possible. Further, since the water content of the mud is reduced by dehydration, the required amount of the slow-hardening solidifying material is smaller than in the conventional case.
[0040]
Moreover, according to the method for treating mud according to the third aspect of the present invention, the dewatering action is promoted, and the water content of the mud can be reduced more efficiently.
[0041]
Further, according to the mud treatment method of the present invention according to claim 4, if the water-permeable bags are stacked in several stages, the water-permeable bag is sufficient even in a relatively small space. There is also an effect that a load can be loaded.
[0042]
Moreover, according to the mud disposal method of the present invention according to claim 5, since it is not necessary to secure a waste disposal site and the resources are reused, there is also an effect of greatly contributing to environmental protection.
[0043]
[Brief description of the drawings]
FIG. 1 is a flowchart showing a procedure of a mud treatment method according to the present embodiment.
FIG. 2 is a layout view of facilities for performing a mud disposal method according to the present embodiment.
3 is a detailed cross-sectional view taken along the line AA in FIG. 2;
FIG. 4 is a graph showing the operation of the mud treatment method according to the present embodiment.
[Explanation of symbols]
4 dredged mud
7 Slow-hardening cement (slow-hardening solidification material)
8 Mixed mud 11 Permeable bag

Claims (5)

  A method for treating mud by adding a slow-hardening solidifying material to mud and stirring to form mixed mud, filling the mixed mud in a water-permeable bag and leaving it for a predetermined time, wherein the slow-hardening solidifying material is made of slow-hardening cement. A method for treating mud characterized by comprising.   A method for treating mud by adding and stirring a slow-hardening solidifying material to a mud to make a mixed mud, filling the mixed mud in a water-permeable bag and leaving it for a predetermined time, wherein the slow-hardening solidifying material is a super-retarding agent and A method for treating mud characterized by comprising cement.   The method for treating mud according to any one of claims 1 to 2, wherein a predetermined load is loaded on the water permeable bag filled with the mixed mud during the standing.   The method for treating mud according to claim 3, wherein the permeable bag filled with the mixed mud is stacked during the standing.   The method for treating mud according to any one of claims 1 to 2, wherein the water permeable bag after the leaving period has elapsed is reused as a banking material, a bank material, or a landfill material.

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