JP2618801B2 - How to prevent sludge particles from floating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a floating prevention method for preventing sludge particles floating on the bottom of a lake or marsh from rising and floating.

[0002]

2. Description of the Related Art Generally, sludge deposited on the bottom of a lake or the like does not cause much harm as long as it remains deposited unless it is highly toxic. Sludge is composed mainly of extremely fine particles of mineral waste such as sludge and organic matter, and easily rises into the water when the surface of the water is rough and is difficult to settle, which seriously affects the fishing industry.

For this reason, sludge treatment has become a social problem as one of today's solutions from the viewpoint of environmental protection. Conventionally, dredging is generally used as a treatment method for sludge, but in this case, the excavated sludge is carried to a treatment facility where a predetermined treatment is performed. The sludge transported to the treatment facility is generally used for landfilling after adding a coagulant to agglomerate, reducing the volume by pressing, drying.

[0004]

However, such a conventional processing method has problems of low efficiency and high cost. On the other hand, it is conceivable to directly inject flocculants into the sea, lakes, marshes, ponds, etc. without dredging to flocculate sludge, but this is technically and economically impractical.

The present invention has been made in view of such circumstances, and an object thereof is to provide a method of preventing sludge particles from floating in water by a simple means.

[0006]

According to the present invention, in order to achieve the above object, the present invention is characterized in that granular cotton of inorganic fibers is put on the upper surface of a sludge layer deposited on the bottom of a lake or the like. It is characterized in that an accumulation layer is formed and sludge particles are gradually trapped in the capillaries between the fibers of the granular cotton to form a granular mass by the movement of water.

Inorganic fiber granular cotton has a particle size of 10 to 10.
It is characterized in that the thickness is 30 mm, the density is 150 to 300 kg / m ³ , the bulk density is 100 to 250 kg / m ³ , and the average fiber diameter is 4 to 6 μm.

[0008]

According to the present invention, on the upper surface of the sludge layer deposited on the bottom of the water, granular cotton of inorganic fiber is applied to the sludge layer having a thickness of 30%.
It is added so as to be about 70%, and by its natural sedimentation, an accumulation layer of granular cotton covering the upper surface of the sludge layer is sequentially formed, and sludge particles can be prevented from soaring in water. Further, with the passage of time, the sludge particles are gradually trapped in the capillaries between the fibers of the granular cotton by the flow of water, and the sludge particles can be prevented from floating. Once trapped, the sludge particles are not easily released from the granular cotton and do not fly up and float in the water.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view showing a usage example of the present invention.

In the figure, reference numeral 1 denotes granular cotton of inorganic fibers, the particle diameter of which is preferably 10 to ³⁰ mm, and the density of each granular cotton 1 is suitably 150 to 300 kg / m ³ . The bulk density of such granular cotton 1 is 100 to 2
It is 50 kg / m ³ . The average fiber diameter is preferably about 4 to 6 μm.

As a specific material of the granular cotton 1, inorganic fibers such as rock wool, alumina fibers, and ceramic fibers are optimal, but are amorphous and more flexible than those having relatively brittle crystals. Preferred is rock wool, which is relatively inexpensive in terms of cost.

The density and fiber diameter of the granular cotton 1 used in the present invention are as described above, but if the density of the granular cotton 1 is too low, the continuity of the capillaries between the fibers is increased and the capillary diameter is large. The sludge particles easily pass through the capillaries. On the other hand, if the density of the granular cotton 1 is too high, the continuity of the capillaries between the fibers decreases, and it becomes impossible to efficiently capture sludge particles. It is important to select the density and fiber diameter of the cotton 1.

Furthermore, by using inorganic fibers having high flexibility as the granular cotton 1, the fibers are entangled with each other in a complicated manner, and the capillary between the fibers has a complicated shape. Therefore, by appropriately selecting the density and fiber diameter of the granular cotton 1, the capillaries are appropriately continuous. As a result, a capillary having a configuration like a maze as schematically shown in FIG. 2 is obtained. Therefore, the once trapped sludge particles are retained in the capillaries and cannot be easily released from the granular cotton 1.

Regarding the particle size of the granular cotton 1, it is necessary to consider the total length of extension of the capillary tube to be as long as possible, to easily obtain a desired density, and the filling property.

In the case of the present invention, it is effective to add a binder or a coupling agent in order to prevent defibration caused by the continuous immersion of the granular cotton 1 in water for a long time. As the binder, a binder having excellent water resistance is preferable. For example, a phenol resin may be used. As the coupling agent, a silane coupling agent, for example, methyltrisilane,
It is preferable to use vinyltriethoxysilane, ethyl-trimethoxysilane, or the like.

Next, an example of use of the present invention will be described with reference to FIG. 1. Reference numeral 2 denotes a water bottom of a lake, and a sludge layer 3 is deposited on the water bottom 2. The granular cotton 1 was added so that the thickness of the sludge layer 3 was about 30 to 70%,
An accumulation layer 4 of granular cotton 1 covering the upper surface of the sludge layer 3 is formed by natural sedimentation. The surface of the integrated layer 4 has irregularities in accordance with the shape of the upper surface of the sludge layer 3, but the surface gradually changes to a uniform surface due to the flow of water or the like. 5 can be prevented, and the sludge particles are gradually trapped in the capillaries between the fibers of the granular cotton 1 by the flow of water, so that the sludge particles can be prevented from floating.

FIG. 3 is a diagram showing the relationship between the degree of transparency and the turbidity as an effect of the present invention, which is obtained by an experiment conducted by the present inventors.

The experiment was conducted by the following method. First, JI
Granules of rock wool as specified in S-A9504 were obtained to obtain rock wool granular cotton having a particle diameter of about 10 to 30 mm. As a result, the bulk density of the obtained granular cotton was about 120 kg / m ³ . Next, 100 ml of the sludge collected from the lake was placed in a beaker, and water was added thereto.
And 100 ml, after stirring it, a granular cotton of the rock wool and about 10g poured and shaken at about 20H _Z 24 hours. Thereafter, the translucency was measured using a transparometer (item code CODE8053-051 manufactured by Shibata Scientific Instruments Co., Ltd.). In addition, about the thing which does not throw in granular cotton, it measured on the same conditions.

As a result, it was confirmed that the transparency when the granular cotton was added was 29.5 cm, whereas the transparency when the granular cotton was not added was 11.5 cm. The relationship between the degree of transparency and the turbidity is as shown in FIG. 3, and the effect of improving the turbidity was recognized by using the granular wool of rock wool, and it was confirmed that the sludge particles were captured by the granular cotton. Was.

[0020]

As described above, according to the present invention,
It is possible to prevent sludge from rising and floating by a very simple means of putting granular cotton of inorganic fiber into the bottom of a lake such as a lake where sludge is deposited.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a usage example of the present invention.

FIG. 2 is a schematic diagram schematically showing a continuous state of capillaries inside granular cotton.

FIG. 3 is a diagram showing the relationship between the degree of transparency and turbidity according to the present invention.

[Explanation of symbols]

 1 Granular cotton 2 Lake bottom 3 Sludge layer 4 Granular cotton accumulation layer

Claims (2)

(57) [Claims] 1. An inorganic fiber granular cotton is charged on an upper surface of a sludge layer deposited on a water bottom of a lake or the like to form a granular cotton accumulation layer, and sludge particles are gradually reduced by the movement of water. A method for preventing the sludge particles from floating, characterized in that they are trapped in the capillaries between the fibers to form a granular mass. 2. The inorganic fiber granular cotton has a particle size of 10 to 3
0 mm, density 150-300 kg / m ³ , bulk density 1
The method for preventing floating of sludge particles according to claim 1, wherein the method has an average fiber diameter of 0 to 250 kg / m ³ and an average fiber diameter of 4 to 6 μm.