JPH0336596B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention is applicable to bottom sediments such as soft sludge layers such as sludge deposited on the bottom of rivers, lakes, inner bays, shallow sea areas, etc., and bottom water in anoxic conditions. When purifying or improving
It relates to methods for improving water quality and bottom sediment that do not adversely affect fish, shellfish, algae, etc. due to water pollution or rapid increases in water PH values.

[Conventional technology]

Conventionally, in order to improve the bottom quality of the soft sludge layer that accumulates on the bottom of rivers, lakes, inner bays, shallow waters, etc., it has not been possible to spray peroxides such as calcium peroxide and potassium peroxide onto the sludge layer. , supplies oxygen into the soft sludge layer and is very effective in improving the bottom sediment, and also phosphorus, which is a nutrient substance from the soft sludge,
It is a well-known fact that it is very effective in suppressing the elution of nitrogen, etc. and organic substances, and in immobilizing heavy metals, etc. in underwater sludge.

However, when the peroxides, etc. mentioned above are sprayed into water, problems such as suspension in the water, diffusion of the suspended water into the surrounding water area, and rapid increase in the pH value of the water may occur, resulting in adverse effects on fish, shellfish, algae, etc. ing.

It is also a well-known fact that covering the sludge layer with sand is effective for purifying and improving the deteriorated water quality and bottom sediment, or for creating and restoring fishing grounds.

However, in general, in such waters where the water quality and bottom sediment environment have deteriorated, there is a significant accumulation of soft sludge, and even if the sand is covered with sand, the covered sand may be buried in the sludge, or even if the sand used for sand covering is Once placed on top of these accumulated sludge, the sand-covered layer and the sludge layer below it are turned upside down and replaced, and the covered sand may be buried in the sludge, or the sand-covered layer may not be covered very well. Even if this is done, it is said that about 20 to 50% of the lower layer of the sand covering layer will remain mixed with the sludge layer and remain stable.
In order to achieve the sand covering thickness excluding this mixed area, it is necessary to cover with sand material approximately twice as much as the planned sand covering layer, which requires extremely extra construction costs and requires a lot of work. There was a problem with inefficiency.

[Purpose of the invention]

The present invention was made in order to solve the above-mentioned conventional problems, and uses peroxides such as calcium peroxide and potassium peroxide for improving the bottom quality of the soft sludge layer at the bottom of the water by suspending or submerging them in water. To provide a method for improving water quality and bottom quality, which can be spread without a sudden increase in PH value, and can reduce sand covering costs by exhibiting a sand covering effect during sand covering for bottom quality improvement. The purpose is to

[Summary of the invention]

The method for improving water quality and sediment of the present invention to achieve the above object is to store calcium peroxide, potassium peroxide, It is characterized by filling with peroxide and spreading it on the bottom of water such as soft sludge. Suspension in water and pH in water
If a sudden increase in value does not occur and the water-soluble material begins to dissolve in water after a predetermined period of time, peroxide gradually reacts with water and begins to supply oxygen to the water and bottom mud, causing oxygen-deficient bottom water. In addition to eliminating lumps, it is possible to suppress the elution of nutrient salts and organic substances from the bottom mud, and to immobilize heavy metals and the like in the bottom mud.

In addition, peroxides such as calcium peroxide and potassium peroxide are filled into a rod-shaped water-soluble member that dissolves after a predetermined period of time, and after being spread on the soft sludge layer at the bottom of the water,
Another feature of the present invention is that the sand is covered with sand on top of the sludge. In addition to reducing construction costs, it also reduces the elution of nutrient salts and organic substances from the bottom mud by improving the bottom sediment by covering with sand and supplying oxygen to the bottom mud under the sand-covering layer using peroxide. The long-term suppression will also improve the bottom quality, and the bottom quality improvement effect of the sand-covered layer can be maintained.

〔Example〕

Examples in which the method for improving water quality and bottom sediment of the present invention is applied will be described below with reference to the drawings. In Example 1 shown in FIG. This shows the case of sand covering, and before sand covering, peroxide is filled on top of the sludge layer 1 into a rod-shaped water-soluble member 2 that dissolves after a predetermined time as shown in Figure 5-A. After spreading the sand as shown in the figure, the sand material 3 is covered with sand.

As a result, the rod-shaped water-soluble member 2 functions as a sand-covering support material, but the material is made of carbon, methyl, cellulose, etc.
A tube with a diameter of 3.0 cm and a length of about 0.5 to 3.0 m is used, but these dimensions are selected as appropriate depending on the purpose of use and the water area.

The water-soluble member 2 may be made of a material other than carbon, methyl, or cellulose as used in this embodiment, but the period for completion of water-soluble material should be set from 2 to 3 in consideration of the purpose of use, construction period, effects, etc. The period shall be selected as appropriate, from about 1 day to about 1 to 2 months.

Inside such a rod-shaped water-soluble member 2, a fifth
As shown in Fig. -B, Fig. 5-C, Fig. 5-D and Fig. 5-E, by filling powder or granules 5 of peroxide such as calcium peroxide, potassium peroxide, etc. Powder or granules 5 of peroxides such as calcium oxide and potassium peroxide can supply oxygen to the bottom water and the sludge layer 1, and can also suppress the elution of nutrient salts and organic substances from the sludge layer 1. When dispersing peroxide powder or granules 5 such as calcium peroxide, potassium peroxide, etc., there is no contamination of the water or a sudden increase in the PH value of the water.

Next, when using the rod-shaped water-soluble member 2 as a sand-covering support material as shown in FIG. In the above, the particles are sprinkled on the water surface using a predetermined device from aboard a ship, etc., but they may also be sprinkled by hand in a small area of water.

The scattered water-soluble materials 2 fall into the water and are randomly assembled on the surface layer of the soft sludge layer 1 as shown in Fig. 2, and are deposited on the bottom in an overlapping state. It doesn't matter if it's coarse or dense. In this Example 1, it was confirmed that it is desirable to set the coating thickness of the water-soluble member 2 to about 2 to 10 cm depending on the thickness of the sludge layer 1, the thickness of the sand material 3 to be covered, and the purpose of use. ing.

When the sand material 3 is covered with the water-soluble material 2 distributed and deposited on the sludge layer 1 as described above, the water-soluble material 2 acts as a support material and the sand material 3 is buried in the sludge layer 1. It also prevents the phenomenon of reversal with the sludge layer 1 below, making it easy to achieve the sand covering thickness as planned.
and can be achieved efficiently.

In this way, the sand material 3 can be loaded onto the surface layer of the sludge layer 1 that has been deposited uniformly to a predetermined thickness during sand covering, so that the sand covering layer is gradually and uniformly deposited over time. The sludge layer 1 under the sprayed layer of the water-soluble member 2 sinks, and although it depends on the properties of the sludge layer 1 and the thickness of the sand covering layer, the sinking almost subsides within a certain period of time, for example, about 1 to 2 months. , it can be stabilized within a shorter period of time than conventional construction methods.

As described above, it is sufficient to allow the water-soluble member 2 to dissolve just when the consolidation settling of the sludge layer 1 is completed and the role of the water-soluble member 2 as a sand-covering support material is completed. Here, as mentioned above, if powder or granules 5 of peroxide such as calcium peroxide and potassium peroxide are filled in the water-soluble member 2, peroxide such as calcium peroxide and potassium peroxide can be The powder or granules 5 begin to melt and cover the surface layer of the sludge layer 1.
A chemical reaction occurs, supplying oxygen to the sludge layer 1, and suppressing the elution of nutrient substances such as phosphorus and nitrogen, as well as organic substances, from the sludge layer 1. It will serve as a water quality improving or purifying agent for the bottom water above.

Next, in Embodiment 2 of FIG. 3, a water-soluble member 2 similar to the above, which is cylindrical as shown in FIG. 5-F or spherical as shown in FIG. By distributing peroxide powder or granules 5 such as calcium peroxide, potassium peroxide, etc. as shown in the plan view in Figure 4, the sediment and water quality of the water area can be purified and improved. It shows you how to do it.

Note that the shape of the water-soluble member 2 is as follows:
A cylinder in Figure 5-B, a triangular prism in Figure 5-C, a square prism in Figure 5-D, a hexagonal prism in Figure 5-E,
A cylindrical shape as shown in FIG. 5-F or a spherical shape as shown in FIG. 5-G shall be appropriately selected depending on the usage.

〔Effect of the invention〕

As explained above, in the method for improving water quality and bottom sediment of the present invention, when covering a sludge layer on a soft water bottom with sand, the sand material may be buried in the sludge layer, or the sand material may be buried in the sludge underneath. There is no reversal of the layer, the supporting capacity of the sand capping is increased, and the amount of sand material used for sand capping is reduced, which reduces construction costs and improves work efficiency. be.

In addition, when peroxide is applied to the sludge layer, it is possible to prevent the occurrence of suspension in water and a sudden increase in the pH value of water, and as a result, it is possible to prevent the spread of suspended water into surrounding waters, which can cause damage to fish, shellfish, algae, etc. This has the effect of not causing any adverse effects.

In addition, water-soluble materials that dissolve after a predetermined time are extremely cheap, such as carbon, methyl, and cellulose, and compared to conventional methods, they are extremely simple, low-cost, and safe to remove sediment from the bottom. It has the advantage of being able to carry out improvement work.

In addition, water-soluble materials filled with powder or granules of peroxides such as calcium peroxide and potassium peroxide will dissolve over time, and the powder of peroxides such as calcium peroxide and potassium peroxide inside will dissolve. The powder and granules gradually dissolve on the surface layer of the sludge layer and supply oxygen to the bottom water and the surface layer of the sludge. Compared to the case where the granules are sprinkled onto the sludge layer in an exposed state, there is an advantage that the water quality and sediment improvement effects are more sustainable.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing a state in which a sludge layer on the water bottom is covered with sand in Example 1 to which the method for improving water quality and bottom sediment of the present invention is applied, and FIG. 2 is a plan view of the water-soluble member shown in FIG. 1. , FIG. 3 is a side sectional view showing the state of the sludge layer at the bottom of the water in Example 2 during improvement, FIG. 4 is a plan view of the water-soluble member in FIG. 3, and FIGS. 5-A to 5-G. 1A and 1B are perspective views of water-soluble members of different shapes that are applied to the method of the present invention. 1...Sludge layer, 2...Water-soluble member, 3...Sand material, 5...Peroxide.

Claims (1)

[Claims] 1. A method for improving water quality and bottom sediment, in which peroxides such as calcium peroxide, potassium peroxide, etc. are filled in a water-soluble material that dissolves after a predetermined period of time, and then sprinkled on the bottom of the water. 2. A method for improving water quality and bottom sediment, in which peroxides such as calcium peroxide, potassium peroxide, etc. are filled in a rod-shaped water-soluble member that dissolves after a predetermined period of time, and the peroxide is spread on the bottom of the water, and then the top is covered with sand.