JP6308512B2 - Pollution diffusion prevention method near the bottom of the water during dredging - Google Patents

Description

The present invention relates to a method for preventing the diffusion of pollution near the bottom of a water during drought.

In recent years, dredging of water beds such as lakes, rivers, dam lakes, and harbors has been carried out. A grab frame is used as a method of suppressing the diffusion of pollution during such drought. The grab frame has a float section partitioned by a buoyant body on the water surface and a curtain membrane section surrounded by water. Is deeper than the water depth, the actual condition is that the dirt diffuses from the bottom of the curtain film during mud.

Therefore, as a method for suppressing the diffusion of pollution during conventional dredging, for example, a flocculant filler that contains a flocculant in the curtain film part and is capable of eluting the flocculant with water is attached at intervals in the horizontal and vertical directions. Has been proposed in which the flocculant is brought into contact with the curtain membrane portion to which the flocculant filler is attached, and the pollutant is agglomerated with the eluting flocculant.
In addition, the flocculant filler is directly attached to the grab bucket, and the contaminated water is brought into contact with the flocculant filler and stirred by flowing water when the grab bucket is poured into the water, dredging, or during muddying. A method of aggregating with the eluting flocculant has been proposed. In the construction method in which the flocculant filler is attached to the curtain film portion, the flocculant is always in contact with water, so that the elution time is fast, but the agglomeration effect is worsened because the agitation necessary for aggregation is insufficient. . In addition, the construction method in which the flocculant filler is directly attached to the grab bucket has a lot of work in the grab bucket underwater, such as when the grab bucket is poured into the water, dredging, and during mud, and the stirring effect is sufficient. The grab bucket is not always in water, and the elution time of the flocculant filler is short, so there is a drawback that the coagulation effect is deteriorated.

Japanese Patent No. 2516742

The present invention has been completed as a result of various researches on a construction method capable of preventing the diffusion of pollutants near the bottom of the water by dripping the solid flocculant.

That is, the present invention is a method of preventing diffusion near the bottom of the water at the time of dredging and pollution at the time of drainage by spreading the solid flocculant in advance on the pollutant at the bottom of the water.

According to the method of preventing diffusion near the bottom of the water at the time of dredging of the present invention, a solid flocculant is sprayed in advance on the bottom mud, and after dissolution, the mixture is stirred with a grab bucket or a pump dredger ladder, etc. It is possible to agglomerate the flocculant at a high concentration in the turbid substance at the time of drought, and to effectively prevent the pollution at the time of small scale high turbidity of the pollution source.

Further, according to the present invention, when the pollutant and the solid flocculant are brought into contact with each other at a high concentration, reliable aggregation can be achieved.

Furthermore, according to the present invention, the aggregated particles settle and contact and agglomerate again to the turbidity, thereby enabling clarification in water.

The perspective view which shows the dredger which fixed the grab frame to the grab type dredger, and lowered | hung the grab bucket which attached the flocculant filler which the coagulant | flocculant was contained and the flocculant could be eluted with water was attached. The perspective view which shows that the diver is spraying the solid flocculant on the water bottom. The perspective view which shows the dredging which lowered | hung the grab bucket which attached the solid flocculant filling body which contains the solid flocculant of a grab type dredger and which can elute the solid flocculant with water after spraying the solid flocculant on the water bottom.

Next, the present invention will be described with reference to the drawings, but the present invention is not limited to the following description.
FIG. 1 is a perspective view showing a dredger in which a grab bucket 6 to which a grab frame 3 is fixed to a grab dredger 1 and a flocculant filling body 7 containing a flocculant and from which the flocculant can be eluted is attached is lowered into water. When the grab bucket 6 is lowered into the water, when it is thrown into the water, when dredging, when mud, etc., the water is stirred to bring the contaminated water into contact with the flocculant filler 7 and stir to remove the pollutant. The glove bucket 6 is not always in the water, and the elution time of the flocculant filler 7 is small, so that the aggregation is worsened and the length of the curtain film part 5 is greater than the depth of water. If it is short, it means that the non-aggregated pollutant diffusing substance diffuses from the bottom of the curtain film part 5 when the mud is pumped.

In FIG. 2, the diver 8 dives before dredging and excavation work, and the solid flocculant 10 is sprayed on the bottom 9. By spraying the solid flocculant 10 to the water bottom 9, a solid coagulant 10 with time becomes gel-absorb water, not scattered and diffused in the stream, agglomeration is promoted, pollutants and flocculant By contacting at a high concentration, reliable aggregation can be achieved.

As a method of spraying the solid coagulant 10 of the present invention, the diver 8 dive before construction work is carried out with dredging, drilling, depending on the size of one of the solid flocculant 10, the solid flocculants Although it is desirable to arrange 10 at intervals of about 1 m in the vertical and horizontal directions, depending on the work process or the current situation, about 100 may be sprayed per 100 m ² from the water or from the water.

3, the water bottom 9 were sprayed with the solid flocculant 10, to the grab type dredgers 1, in which dredging lowering the grab bucket 6 attached to coagulant filling body 7 in water. The grab bucket 6 grips the dredged material and the solid coagulant 10 in the water bottom 9, by pollutants and flocculant contacts at a high concentration, it is reliable agglomeration. By pollutant and the solid coagulant 10 contacts, agglomerated particles made is contacted aggregate settling again contaminants, achieving clarification of water turbid water, it is possible to increase the water clarity.

The prior work present invention carried out the dredging-drilling, and laid the solid flocculant 10 to the water bottom 9, instantly pollution diffusion due to mechanical impact during dredging that may arise from the dredging by the grab bucket 6 In addition to keeping it within a small range by re-contacting and agglomerating, sedimentation and separation water of dredged sediment can be clarified.

  The earth and sand dredged by the grab bucket 6 is transferred to the earth transport ship 2 provided alongside the grab dredger 1. In addition to dredged sand, a large amount of discharged turbid water is stored in the earth ship 2, and the settled separated water that has been clarified in the solid / liquid separated water is returned to the grab frame 3, Since the mud load can be further increased and the dredged sand can be stored on the earth ship 2, the work efficiency due to the increase in the amount of mud stored in the earth ship 2 can be increased.

Further, as shown in FIG. 3, by attaching the flocculant filler 7 to the grab bucket 6, the diffused pollutants in the grab frame 1 can be used when the grab bucket 6 is poured into water, dredged, mud pumped, etc. By agitation with water flow, coagulation and precipitation can be achieved, and the water can be made transparent.

The solid coagulant 10 of the present invention, unlike the liquid coagulant, so take a long time is life flocculant retarded solubility, if laid on the bottom mud advance dredging planned, in high concentrations in peripheral during dredging Mixing with mud and preventing the spread of stirring pollution during dredging, the particles are optimal because they have a re-agglomeration effect and prevent further diffusion by the new mud.

Applications of the present invention, by spraying the solid flocculant 10 prior to the water bottom 9, it is also preferable to increase the perspective of the suspension in water under the water depth, such as disaster waters and dams.

DESCRIPTION OF SYMBOLS 1 .... Grab-type dredger 2 .... Soil ship 3 .... Grab frame 4 .... Float part 5 .... Curtain part 6 .... Grab bucket 7 .... Agglomeration Filler 8 ... Diver 9 ... Water bottom 10 ... Solid flocculant

Claims (1)

Before the dredging / excavation work, a delayed-soluble solid flocculant is sprayed on the pollutant diffusion material at the bottom of the water and mixed with the pollutant diffusion material. A construction method that prevents pollution during mud.

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