JP2005279324A - Method for improving mud quality and water quality of tide-sensitive river - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for improving the mud quality and water quality of tide-sensitive rivers capable of improving the mud quality and water quality of the tide-sensitive rivers by supplying oxygen to bottom mud using the tiding of the tide-sensitive rivers. <P>SOLUTION: A mud quality/water quality improving cylinder 10 is filled with a modified material 21 good in water permeability and embedded in the river beds of the tide-sensitive rivers 1. Herein, the modified material 21 may be embedded in the river beds so that the upper surfaces of the mud quality/water quality improving cylinders 10 become to vicinity of the surfaces of mud deposited on the river beds of the tide-sensitive rivers 1. Further, the modified material 21 may be solid particulates such as stones, alkaline solid particulates or coal ash solid particulates. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention uses a tide of a tidal river to purify the nature of the bottom mud accumulated in the tidal river (hereinafter referred to as “mud”) and the water quality of the river water by a rational method. It relates to a method for improving mud quality and water quality of tidal rivers that can be improved.

For example, urban rivers such as the Ota River in Hiroshima City (especially tidal rivers with tides) are rivers due to “stagnation of running water”, “deposition of sludge”, “increasing nutrient inflow of nutrients”, etc. The purification function is being impaired, and this causes the following situation.
(1) Deterioration of water quality, generation of bad odors (hydrogen sulfide, etc.) (2) Loss of waterside landscape value and separation of people from watersides (3) Decline in human mobility and inhibition of urban activation Under these circumstances, River managers are promoting efforts to purify urban rivers (especially tidal rivers).

Conventionally, as a method for purifying the water quality of a river, for example, there are those disclosed in the following three patent documents.
JP-A-5-131196 Japanese Patent Laid-Open No. 10-15538 JP 2001-29951 A

Patent Document 1 (Japanese Patent Application Laid-Open No. 5-131196) discloses that a natural polluted water environment is generally in an acidic state. Therefore, shells and alkaline solid particles having an alkalinity (slag, coal ash) Contamination, etc.) In the water, an environmental purification structure filled with a water-permeable frame is used to dissolve the alkali in the shells and alkaline solid particles into the water, resulting in acid pollution. Disclose the purification of water environments such as seas, harbors, rivers, marshes, ponds, dams, etc. by neutralizing or mitigating water.
Moreover, the said patent document 1 is also disclosing that the useful microbe and small animal which have a water purification effect can inhabit and propagate on the surface of a shell and an alkaline solid granule, and can further promote the water purification effect.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 10-15538) discloses that a heat-treated shell fossil used as an absorbent of ammonia nitrogen, nitrite nitrogen, and phosphorous phosphorus is introduced into the bottom of the water, so that the bottom sediment and the vicinity thereof can be obtained. It is disclosed that by promptly attenuating materials that are negative factors in the sea area, the bottom quality and water quality are improved, and a good environment for benthic animals appears.

  Patent Document 3 (Japanese Patent Application Laid-Open No. 2001-29951) discloses that an artificial zeolite obtained by subjecting coal ash to hydrothermal chemical treatment is laid on the upper surface of a sedimentary mud layer in a sea area, thereby closing the inner bay. Is disclosed to prevent water pollution caused by eutrophication with nutrient salts and gas in various sea areas.

  However, the above three patent documents all saturate the reforming material (mud quality / water quality improving agent) in the water (in the sea) and always expose it to the water (sea water). There is no disclosure about how to improve river bottom quality and water quality by eliminating it.

  The object of the present invention is to improve the bottom quality of the river by oxygen supply to the bottom mud using the tide of the tidal river and to reveal the good habitat environment of the bottom organism that induces the purification action of the bottom mud. It is to provide a method for improving mud quality and water quality that can not only promote improvement of water quality but also improve water quality of rivers.

The method for improving the mud quality and water quality of a tidal river (1) with tides according to the present invention inhibits the flow between the modified material (21) and the bottom mud with the modified material (21) having good water permeability. The muddy / water quality improvement cylinder (10) which is a non-contained container is filled, and the muddy / water quality improvement cylinder (10) is embedded in the river bed of the tidal river (1).
The muddy / water quality improvement cylinder (10) is embedded in the river bed so that the upper surface of the muddy / water quality improvement cylinder (10) is close to the surface of the mud collected in the river bed of the tidal river (1). Also good.
The modified material (21) may be a solid particle such as gravel.
The modifying material (21) may be an alkaline solid particle.
The modified material (21) is a coal ash material (hereinafter referred to as “coal ash granulated material”) obtained by adding coal ash generated from a thermal power plant to a main material and granulating it with a granulation method. May be.
When the modified material (21) is an alkaline solid granule or coal ash granule, the insoluble / immobilized phosphorus dissolved in water of the alkaline solid granule or coal ash granule (hereinafter referred to as "immobilization of phosphorus"). The modified material (21) whose ability has been saturated may be recovered, and the recovered modified material (21) may be utilized as, for example, a water-permeable civil engineering material.

The mud and water quality improvement method for a tidal river with tides according to the present invention has the following effects.
(1) By burying a muddy / water quality improvement cylinder filled with a material with good permeability in the river bed of the tidal river, oxygen is supplied to the bottom mud by the tide of the tidal river, and the bottom mud is reduced. Disappears. Moreover, more oxygen is supplied by reaching the muddy / water quality improvement cylinder to the gravel layer below the bottom mud. Thereby, generation | occurrence | production of hydrogen sulfide is suppressed, and nitrogen etc. in bottom mud can be removed because bottom mud will be in an aerobic state. In addition, a good habitat for living organisms that induce the purification action of the bottom mud can be produced in and around the bottom mud and the mud / water quality improvement cylinder, and the improvement of the mud quality is further promoted.
(2) Alkaline solid granules and coal ash granulates have the ability to fix phosphorus in the bottom mud, so that not only the bottom quality is improved, but also the phosphorus contained in the bottom mud is fixed. Elution of phosphorus into water can be suppressed, and river water quality can be improved.
(3) By using coal ash granulated material as a reforming material, it is possible to effectively utilize coal ash generated from a thermal power plant.
(4) The modified material in which the phosphorus immobilization ability is saturated can be recovered, and the recovered modified material can be used as, for example, a permeable civil engineering material.

The purpose of improving river mud quality and water quality by supplying oxygen to the bottom mud using the tide of the tidal river is to improve the permeability of the tidal river and the bottom mud in contact with it. This was realized by creating aerobic environment by supplying oxygen by generating water flow.
In addition, the purpose of improving the mud and water quality of rivers by fixing phosphorus, which is an inducer such as red tide, was realized by using alkaline solid particles or coal ash granules.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the method for improving the quality and quality of tidal rivers according to the present invention will be described below with reference to the drawings.
FIG. 1 is a horizontal cross-sectional view of a muddy / water quality improvement cylinder for explaining a method for improving muddy and water quality of a tidal river according to an embodiment of the present invention, and FIG. 2 is a tidal sense according to an embodiment of the present invention. It is a muddy / water quality improvement cylinder installation top view for demonstrating the muddy nature of a river, and a water quality improvement method.
In the tidal river water quality improvement method according to the present embodiment, as shown in FIG. 1, the muddy / water quality improvement cylinder 10 filled with the highly water-permeable modifying material 21 has a feeling of tides. Many are buried in the riverbed of the tidal river 1.

  Further, each of the muddy / water quality improvement cylinders 10 is embedded so that the upper surface thereof is in the vicinity of the surface of muddy soil (for example, sludge layer) accumulated on the river bed. As a result, river water containing dissolved oxygen due to the tide can effectively pass through the muddy / water quality improvement cylinder 10 and oxygen can be added to the bottom mud through each muddy / water quality improvement cylinder 10 at low tide. Can be supplied.

  Further, as shown in FIG. 2, each of the muddy / water quality improvement cylinders 10 has a cylindrical shape, and an effective reforming range is provided by arranging the muddy / water quality improvement cylinders 10 in a staggered manner along the river shore. C can be obtained.

  As the reforming material 21 filled in the muddy / water quality improvement cylinder 10, alkaline substances such as coal ash, red clay, calcium carbonate as disclosed in the above-mentioned Patent Document 1 (Japanese Patent Laid-Open No. 5-131196) are used. Although it is possible to use a material that has been solidified with a small amount of a binder such as cement, it is possible to effectively use coal ash by using a coal ash granule as shown below.

Coal ash granulated material is obtained by, for example, mixing 100% combustion ash (hereinafter referred to as “fluidized bed ash”) of coal-fired fluidized bed thermal power plant and 15% water (relative to fluidized bed ash). Manufactured by a granulation method to make particles having a diameter of 10 to 15 mm, and has physical properties as shown in Table 1.

In addition, the coal ash granule has excellent phosphorus removal performance as shown in FIG. 3 as an example of the test results (phosphorus removal performance in bottom mud by coal ash granulation using fluidized bed ash). Compared to the conventional measures to cover eutrophic seawater with coal sand, coal ash granulation is a material that maximizes the effect of fixing phosphorus in coal ash, which is a raw material. Compared with, it has the ability to prevent elution into water by immobilizing phosphorus which causes red tides.
In addition, coal ash granulated material using fluidized bed ash is also a safe material that satisfies all the environmental items of the “environmental standards related to marine pollution”.
Furthermore, the coal ash granule using fluidized bed ash is a material that is easy to handle and can maintain a stable shape for a long time.

As described above, the method for improving the quality and quality of tidal rivers according to the present embodiment has the following effects of improving the quality and quality of water.
(1) Effect of improving mud quality (a) Since the flow of water containing dissolved oxygen can be generated in each mud / water quality improvement cylinder 10 by tide, or each mud / water quality improvement cylinder at low tide Since oxygen can be supplied to the bottom mud through 10, the reduced state of the bottom mud can be eliminated.
(B) By supplying oxygen to the bottom mud, generation of hydrogen sulfide and the like can be suppressed, and sludge formation of the bottom mud can be prevented.
(C) Since a good habitat environment for benthic organisms can appear, the range of modification can be expanded synergistically.
(D) By supplying oxygen to the bottom mud, the bottom mud becomes aerobic and nitrogen and the like can be removed. Moreover, by using alkaline solid particles or coal ash granulated material, phosphorus in the bottom mud can be immobilized, and elution of phosphorus into river water can be suppressed.
(2) Water quality improvement effect (a) Elution to river water can be suppressed because nitrogen and the like are removed by eliminating the reduced state of the bottom mud.
(B) By using alkaline solid particles or coal ash granulated material as the reforming material 21, phosphorus can be immobilized, so that elution of phosphorus into river water can be suppressed, Immobilization of phosphorus can be achieved.

  When alkaline solid particles or coal ash granules are used, the reforming material 21 in which the effect of fixing phosphorus is saturated can be recovered and easily replaced with a new reforming material 21. The recovered modified material 21 can be used as, for example, a water-permeable civil engineering material.

  In the above description, the muddy / water quality improvement cylinder 10 is cylindrical, but the shape may be any shape (for example, a rectangular cylinder). Moreover, the method of arrange | positioning the muddy / water quality improvement cylinder 10 in a river bed is not restricted to the method shown in FIG. 2, You may arrange | position with arbitrary patterns.

As described above, according to the mud and water quality improvement method of the tidal river of the present invention, the deterioration of water quality due to sludge accumulation and the generation of bad odor, the loss of waterside landscape value and It is possible to prevent people from leaving the water, people from falling in fluidity, and urban activation.
Moreover, the coal ash generated from the thermal power plant can be effectively utilized by using the coal ash granulated material as a reforming material.

It is a mud and water quality improvement cylinder installation cross-sectional view for demonstrating the mud quality and water quality improvement method of a tidal river by the 1st Example of this invention. (Example 1) It is a muddy / water quality improvement cylinder installation top view for demonstrating the muddy quality of a tidal river and the water quality improvement method by 1st Example of this invention. (Example 1) It is a figure which shows an example of the test result which measured the phosphorus removal performance of the artificial aggregate using the fluidized bed ash used as a modifying material. (Example 1)

Explanation of symbols

1 Tidal river 10 Mud and water quality improvement cylinder 21 Reforming material C Reforming range L Interval

Claims (6)

A method for improving the mud and water quality of a tidal river (1) with tides,
Mud and water quality which is a container in which the bottom mud and phosphorus in water are insolubilized and fixed and the water-permeable modified material (21) does not hinder the flow of water between the modified material (21) and the bottom mud. A method for improving the tide and water quality of a tidal river, wherein the improvement cylinder (10) is filled and the muddy / water quality improvement cylinder (10) is buried in the river bed of the tidal river (1).   The muddy / water quality improvement cylinder (10) is embedded in the river bed so that the upper surface of the muddy / water quality improvement cylinder (10) is close to the surface of the mud collected in the river bed of the tidal river (1). The method for improving mud and water quality of a tidal river according to claim 1.   The method for improving mud and water quality of tidal rivers according to claim 1 or 2, characterized in that the modifying material (21) is a solid granule such as gravel.   The method for improving mud and water quality of tidal rivers according to claim 1 or 2, wherein the modifying material (21) is an alkaline solid particle.   The mud and water quality of a tidal river according to claim 4, characterized in that the modified material (21) is a coal ash material obtained by adding coal ash to a main material and granulating it by a granulation method. How to improve. The modified material (21) in which the effect of insolubilization / immobilization of phosphorus is saturated is recovered, and the recovered modified material (21) is utilized as a permeable civil engineering material. Item 1. A method for improving mud and water quality in a tidal river.