JP5872303B2 - Calcium hydroxide-containing granular sand-covered structure and method - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a calcium hydroxide-containing granular sand-covered structure and method suitable for forming an environmental remediation effect and a marine resource environment recovery by forming on the bottom of a closed water area where the amount of organic matter settled is large.

  The bottom mud of closed waters such as inner bays, inlets, and dam lakes is prominent in organic sedimentation, and is generally reductive because dissolved oxygen is consumed by oxidative decomposition of the organic matter. Under such a reducing environment, hydrogen sulfide is generated because sulfate ions are reduced by sulfate-reducing bacteria. Since hydrogen sulfide is oxidized in water, it causes sediment and water quality deterioration such as generation of blue tide and anoxic water mass. For example, between 1979 and 2003, 2 to 25 blue tides were confirmed every year in Tokyo Bay and Ise Bay.

  Such eutrophication and hypoxia lead to a decline in biodiversity and fishery productivity, so the decomposition, volume reduction and stabilization of organic matter can improve water quality and bottom quality in closed waters and biodiversity. This is an important issue from the viewpoint of maintaining fishery productivity.

  In order to solve such a problem, conventionally, as shown in FIG. 5, coal ash granulated material (a kind of granular material containing calcium hydroxide) is used as a sand covering material, and the thickness is about 200 mm. A certain coal ash granule covering sand 2 is laid on the bottom mud 1 of a closed water area (see, for example, Patent Document 1 below).

In addition, in Patent Document 2 below, when an infiltration column made of coal ash granulation is penetrated into a river bed and tidal flat where organic mud is deposited, the excavated soil excavated when the penetration hole is opened is coal ash granulation. A method for improving the hydrophilicity of river tidal flats in which sludge accumulates is disclosed, in which a hydrophilic soil structure material is produced by mixing them with each other to spread them on a tidal flat as a sand covering material.
In Patent Document 3 below, a coal ash granule is laid on the upper layer of the lower landfill layer to form a coal ash granulation layer, and the coal ash granule is formed in a substantially columnar shape on the upper landfill layer. A method for creating an artificial tidal flat is disclosed in which a plurality of sandbags are inserted in a zigzag pattern or a lattice pattern, and the entire surface of the landfill soil layer is covered with a predetermined thickness. ing.

JP 2004-124467 A JP 2009-001961 A JP 2007-170041 A

  However, in the method of laying the coal ash granule-covered sand 2 having a predetermined thickness (= about 200 mm) on the bottom mud 1 in the closed water area, there is no change in the water bottom, and the settled organic matter is almost uniform. As a result of the accumulation, if the mud 3 containing organic matter is deposited thickly beyond the permissible limit of the effect of the coal ash granulated sand-covering sand 2, the problem that the organic matter cannot be sufficiently decomposed, reduced in volume and stabilized. there were.

  An object of the present invention is to provide a calcium hydroxide-containing granular material-covered sand structure in which calcium hydroxide-containing granular material can be laid on the bottom mud of a closed water area to sufficiently decompose, reduce, and stabilize organic matter. And to provide a method.

The calcium hydroxide-containing granular sand-covered structure of the present invention is formed on the bottom of a closed water area where the amount of organic matter settled is large, and is intended to restore the environment and restore the marine resources environment. a granulation, the in浮泥inflow portion by arranging the Sentsutsumi mound like a belt along the浮泥inflow direction浮泥(3) for achieving the inflow prevention to Kutsugaesuna area of the belt-like 1 and a side opposite to the floating mud inflow side of the first sand covering structure as a countermeasure against the floating mud flowing into the sand covering area beyond the first sand covering structure. And the second sand-covering structure (20) disposed adjacent to the first sand-covering structure, wherein the first sand-covering structure is deposited on the bottom of the closed water area ( predetermined thickness by Kutsugaesuna construction using calcium hydroxide-containing particulates on the 1) as Kutsugaesuna material On the formed base part (11), wherein the beveled surface of predetermined slope by Kutsugaesuna construction using calcium hydroxide-containing granules as Kutsugaesuna material (13R, 13L) the浮泥inflow side and該浮mud A first mound portion formed so as to be provided on the side opposite to the inflow side is provided, and the second sand covering structure uses the calcium hydroxide-containing granular material as a sand covering material on the base portion. A plurality of second mound portions formed so as to be linearly arranged at predetermined intervals along the floating mud inflow direction by sand covering construction are characterized in that they are provided .
Here, the first mound portion includes a flat portion (12), and first and second slope portions (13L, 13R) formed with the flat portion sandwiched so as to have a slope having a predetermined slope. May be provided.
The second mound portion may include a conical portion (22) having a slope with a predetermined slope.
The calcium hydroxide-containing granular material may be a coal ash granulated material.

The calcium hydroxide-containing granular sand-covering method of the present invention is formed by forming the calcium hydroxide-containing granular sand-covering structure of the present invention at the bottom of a closed water area where the amount of organic matter settled is large. A method for covering sand with a calcium hydroxide-containing granular material for carrying out sand covering construction using the calcium hydroxide-containing granular material as a sand-covering material and depositing on the bottom of the closed water area ( a first step of forming said base portion on the 1) (11) to a predetermined thickness, carried out Kutsugaesuna construction using the calcium hydroxide-containing granules as Kutsugaesuna material, said first a second step that form a second mound portions of the plurality on the basis of Kutsugaesuna the first mound portion and the second Kutsugaesuna structure of structure (10) (20) of It is characterized by comprising.
Here, in the second step, as the first mound portion, the flat portion (12) and said first and second slope portions (13L, 13R) trapezoidal mound portion having a said and 1 of the inclined surface portion (13L) is formed on the front Symbol foundation as the inclined surface portion of said 2 (13R) is located on the opposite side of the該浮mud inlet side as well as positioned in the浮泥inflow side Also good.
In the second step, the conical portion (22) of the plurality of second mound portions is changed to the conical shape of one second mound portion of the plurality of second mound portions. the conical portion is the floating of the second mound portions plurality few with parts are adjacent along the second inclined surface portion and the浮泥inflow direction of the trapezoidal mound portion of the first mound portion You may form on the said base part so that it may line up linearly along a mud inflow direction.
The calcium hydroxide-containing granular material may be a coal ash granulated material.

The calcium hydroxide-containing granular material-covered sand structure and method of the present invention have the following effects.
(1) By forming a mound portion having a predetermined slope with a calcium hydroxide-containing granular material as a sand covering material on a base portion having a predetermined thickness, the floating mud containing organic matter is uniformly formed. Since accumulation can be prevented, the calcium hydroxide-containing granular material can be laid on the bottom mud of the closed water area to sufficiently decompose, reduce and stabilize the organic matter.
(2) Coal ash granulate, which is a kind of calcium hydroxide-containing granule, has already been confirmed to be safe, such as a content test for environmentally restricted elements, and has a system in place for commercialization and stable supply. Yes. The manufacturing process is also granulated with fly ash produced from a coal-fired power plant using blast furnace cement, and is a by-product of thermal power generation and is low in cost.
(3) The same effect can be expected even when a granule of converter slag is used as the calcium hydroxide-containing granule.

It is a figure for demonstrating the structure of the coal ash granule covering sand structure 10 which is a calcium hydroxide containing granule covering sand structure by one Example of this invention, (a) is a coal ash granule covering sand structure. 10B is a cross-sectional view of the coal ash granulated sand-covered structure 10 (see the coal ash granulated sand-covered structure 10 along the paper surface from the lower side of FIG. 1A). FIG. It is a figure for demonstrating the structure of the coal ash granule covering sand structure 20 which is a calcium hydroxide containing granule covering sand structure by one Example of this invention, (a) is a coal ash granule covering sand structure. 20B is a cross-sectional view of the coal ash granule-covered sand structure 20 (see the coal ash granule-covered sand structure 20 from the lower side of the page of FIG. 2A along the paper surface). FIG. The coal ash granule covering sand structure 10 shown in FIGS. 1 (a) and 1 (b) and the coal ash granule covering sand structure 20 shown in FIGS. 2 (a) and 2 (b) are provided at the bottom of a closed water area. It is a cross-sectional view for demonstrating the structure of the coal ash granule covering sand structure 30 used for the field verification test for confirming the effect when it forms on the deposited bottom mud 1. FIG. It is a graph which shows the result of the field verification test using the coal ash granule covering sand structure 30 shown in FIG. 3, (a) is a graph which shows the inhabitant confirmation of a monkey, (b) is the inhabitant confirmation of a clam. It is a graph which shows. It is a figure for demonstrating the conventional method of laying coal ash granule covering sand of predetermined thickness on the bottom mud of a closed water area.

  For the above purpose, the coal ash granule is sand-covered on the foundation formed in a predetermined thickness using the coal ash granule as the sand covering material on the bottom mud deposited on the bottom of the closed water area. This was realized by forming the mound part so as to have a slope with a predetermined gradient as a material.

Embodiments of the calcium hydroxide-containing granular material-covered sand structure and method of the present invention will be described below with reference to the drawings.
The calcium hydroxide-containing granule-covered sand structure according to one embodiment of the present invention is a coal ash granulated product having a particle diameter of 40 mm or less (Hi beads manufactured by Energia Eco Materia Co., Ltd.) obtained by granulating and solidifying fly ash with blast furnace cement. Is used as a calcium hydroxide-containing granule, and a trapezoidal or conical mound is formed on a base portion having a predetermined thickness in order to prevent the floating mud 3 containing organic matter from being uniformly deposited. It is characterized by having a configuration in which a portion (that is, a mound portion having a slope with a predetermined slope) is formed.

  Specifically, the calcium hydroxide-containing granular material-covered sand structure according to the present embodiment includes a belt-shaped coal ash granulated material-covered sand structure 10 shown in FIGS. 1 (a) and 1 (b), and FIG. 2 (a). , (B) and the coal ash granulated material covering sand structure 20 are included.

  The coal ash granulated sand-clad structure 10 is intended to prevent the inflow of floating mud into the sand-covering area by arranging the submerged mound in a belt shape along the inflow direction of the mud in the floating mud inflow section. And includes a base portion 11 having a height of 200 mm and a mound portion (including a flat portion 12, a left slope portion 13L, and a right slope portion 13R) formed on the base portion 11.

  The foundation part 11 has a thickness of 200 mm (20 cm) by performing sand covering construction using coal ash granulated material as a sand covering material on the bottom mud 1 deposited on the bottom of the closed water area. (See FIG. 1B).

The flat portion 12 constituting the mound portion has a length (length along the floating mud inflow direction; hereinafter the same) = 1,000 mm and height = 500 to 1,000 mm (50 cm to 1 m). It is formed on the foundation part 11 by carrying out sand covering construction using coal ash granulated material as sand covering material.
The height of the flat portion 12 is such that the shallowest water depth is equal to or greater than the water depth that can be navigated by a fishing boat or the like, and the floating mud accumulated on the bottom slope portions of the left slope portion 13L and the right slope portion 13R. 3 (organic matter) thickness (hereinafter referred to as “organic matter deposition thickness”) = (sedimentation deposition thickness−decomposition thickness) × determined between 500 and 1,000 mm so that a maximum useful life of about 200 mm can be secured. It is done.

The left slope portion 13L constituting the mound portion is adjacent to the flat portion 12 on the floating mud inflow side (left side in FIG. 1A), and has a length = 1500 mm (1.5 m) and a gradient (vertical distance). : Horizontal distance) = 1: 1 to 1: 5, and is formed on the base portion 11 by performing sand covering construction using coal ash granulated material as a sand covering material.
Further, the right slope portion 13R constituting the mound portion is adjacent to the flat portion 12 on the side opposite to the floating mud inflow side (right side in the figure), and the length = 1500 mm (1.5 m) and the slope = It is formed on the base part 11 by performing sand-covering construction using a coal ash granulated material as a sand-covering material so that it may become 1: 1-1: 5.

  The coal ash granulated sand-covered structure 20 is for countermeasures against the floating mud 3 that has flowed into the sand-covered area beyond the coal ash granulated sand-covered structure 10, and the interval along the floating mud inflow direction = It consists of a plurality of mound portions (conical portions 22) formed on the base portion 11 so as to be arranged in a straight line at 0 to 100,000 mm (0 to 100 m) (see FIG. 2B).

The conical portion 22 constituting the mound portion has a bottom surface diameter of 10,000 mm (10 m), a height of 500 to 1,000 mm (50 cm to 1 m), and a gradient of 1: 5 to 1:10. It forms on the base part 11 by performing sand-covering construction using coal ash granulated material as a sand-covering material.
In addition, the height of the conical portion 22 is deposited around the conical portion 22 so that the shallowest water depth is equal to or greater than the navigable water depth of a fishing boat or the like, similar to the flat portion 12 described above. The thickness of the floating mud 3 (organic matter) (organic matter deposition thickness) = (sedimentation deposition thickness−decomposition thickness) × determined between 500 and 1,000 mm so that the service life can be secured up to about 200 mm (20 cm) .

  Next, in order to confirm the effect when the coal ash granule covering sand structure 10 and the coal ash granule covering sand structure 20 are formed on the bottom mud 1 deposited on the bottom of the closed water area, FIG. The result of having carried out the field verification test using the coal ash granulated material covering sand structure 30 as shown in FIG.

Coal ash granulated material produced by pulverized coal combustion type thermal power generation is laid on the seabed at a depth of 3.0 to 4.0 m off the east coast of Nakaumi Shimonto, with a size of 110 m x 140 m and a thickness of about 20 cm. The foundation part 31 of the grain covering sand structure 30 was comprised, and it was set as the test area.
In addition, a plurality of trapezoidal mounds 32 of a coal ash granulated material-covered sand structure 30 having a gradient of about 1: 3 and a height of about 1: 3 are formed on the foundation 31 at a water depth of 3.7 to 3.2 m. They were formed side by side at a predetermined interval.

  After 5 years, the accumulation state of the organic floating mud that settles in the coal ash granulated sand-covered sand structure 30 is grasped, and the base portion 31 of the coal ash granulated sand-covered sand structure 30 (floating between adjacent mound parts 32). The growth status of the bivalve was checked according to the level on the slope of the mud 3 and the mound part 32. The target bivalves were salves and clams, which are useful marine resources inhabiting the water area, and the number of the corresponding species inhabiting within a 50 cm × 50 cm frame was measured.

As a result of the investigation, organic floating mud was found to deposit 0.15m above the foundation 31 at a water depth of 3.5m, but about 0 to 1.0cm of mud was deposited thinly on the slope of the mound 32. There was no progress of consolidation just by doing.
In addition, although the inhabitants of monkeys and clams could not be confirmed in the base 31, the upper slopes of the mound 32 were inhabited in a band at a depth of 3.3 m and inhabited in a band at a depth of 3.1 m. (In other words, perennial shellfish inhabited) was confirmed (see FIGS. 4A and 4B).

  As a result, the base portion of the coal ash granule-covered sand structure 20 (provided with a conical mound portion having a slope around 360 °) is adjacent to the right slope portion 13R of the coal ash granule-covered sand structure 10. 11 is formed side by side to prevent the mud 3 containing organic matter from being uniformly deposited on the coal ash granulated material-covered sand structures 10 and 20, and the organic matter of the coal ash granulated material. It was confirmed that the decomposition function could be fully exploited to recover the marine resources.

  In the above description, only one row of the coal ash granule-covered sand structure 10 and the coal ash granule-covered sand structure 20 has been formed. 10 and the coal ash granule covering sand structure 20 may be formed in a plurality of rows.

  Moreover, although the mound part of the coal ash granulated material covering sand structure 20 was made into the cone-shaped part 22, if the height and the gradient are the same, the shape of the bottom of the ellipse or the shape of the bottom of the bottom is rectangular. The shape may be a rectangular part.

DESCRIPTION OF SYMBOLS 1 Bottom mud 2 Coal ash granule covering sand 3 Floating mud 10, 20, 30 Coal ash granule covering sand structure 11, 31 Base part 12 Flat part 13L Left slope part 13R Right slope part 22 Conical part 32 Mound part

Claims (8)

Forming the bottom of the water amount sedimentation often closed water area of the organic matter to a calcium hydroxide-containing granule Kutsugaesuna構granulated for achieving environmental remediation effects and aquatic resources environmental recovery,
A belt-shaped first sand-capping structure for preventing the inflow of floating mud (3) into the sand-covering area by arranging the submerged mound in a belt-like shape along the floating mud inflow direction at the mud-fluid inflow portion. (10) and
Adjacent to the first sand-covering structure on the side opposite to the floating mud inflow side of the first sand-covering structure as a countermeasure against the floating mud flowing into the sand-covering area beyond the first sand-covering structure A second sand-capping structure (20) arranged as
The first sand covering structure is formed to a predetermined thickness by sand covering construction using calcium hydroxide-containing granular material as sand covering material on the bottom mud (1) deposited on the bottom of the closed water area. and on the foundation (11), the inclined surface (13R, 13L) the浮泥inflow side and該浮mud inflow side of the predetermined gradient by Kutsugaesuna construction using the calcium hydroxide-containing granules as Kutsugaesuna material A first mound part formed so as to have the opposite side ,
The second sand covering structure is linearly arranged at predetermined intervals along the floating mud inflow direction by sand covering construction using the calcium hydroxide-containing granular material as a sand covering material on the foundation portion. A plurality of second mound parts formed as described above,
A calcium hydroxide-containing granular material-covered sand structure characterized by that. The first mound portion is
A flat portion (12);
First and second slope portions (13L, 13R) formed across the flat portion so as to have slopes with a predetermined slope;
The calcium hydroxide-containing granular material-covered sand structure according to claim 1, comprising: The said 2nd mound part is provided with the cone-shaped part (22) which has the slope of a predetermined | prescribed gradient, The calcium hydroxide containing granule covering sand structure of Claim 1 or 2 characterized by the above-mentioned.   The calcium hydroxide-containing granular material-covered sand structure according to any one of claims 1 to 3, wherein the calcium hydroxide-containing granular material is a coal ash granulated material. Calcium hydroxide-containing granular sand for forming an environmental remediation effect and recovery of marine resources environment by forming the calcium hydroxide-containing granular sand-covered structure according to claim 1 at the bottom of a closed water area where the amount of organic matter settled is large A method,
Performing Kutsugaesuna construction using calcium hydroxide-containing granules as Kutsugaesuna material, the said base portion (11) of predetermined thickness on the sediment deposited on the sea bed of the closed-water area (1) A first step of forming;
The calcium hydroxide-containing granular material is used as a sand covering material to perform sand covering construction, and the first mound portion of the first sand covering structure (10) and the second sand covering structure (20). a second step of the shape formed on said plurality of second mound portion said base portion,
A method of covering sand with calcium hydroxide containing particulate matter, comprising: Using the calcium hydroxide-containing granular material-covered sand structure according to claim 2,
In the second step, the as first mound portion, the flat portion (12) and said first and second slope portions (13L, 13R) trapezoidal mound portion having a first slope with parts (13L) is located on the浮泥inflow side as the slope of said 2 (13R) is located on the opposite side of the該浮mud inflow side, is formed on the base portion,
The calcium hydroxide-containing granular material covering sand according to claim 5. Using the calcium hydroxide-containing granular material-covered sand structure according to claim 3,
In the second step, the conical portion (22) of the plurality of second mound portions is changed to the conical shape of one second mound portion of the plurality of second mound portions. the conical portion is the floating of the second mound portions plurality few with parts are adjacent along the second inclined surface portion and the浮泥inflow direction of the trapezoidal mound portion of the first mound portion Forming on the base part so as to be arranged in a straight line along the mud inflow direction ,
The calcium hydroxide-containing granule-covering method according to claim 6,   The calcium hydroxide-containing granular material-covering method according to any one of claims 5 to 7, wherein the calcium hydroxide-containing granular material is a coal ash granulated material.

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