JP2008143732A - Bamboo charcoal particle and sea bottom cleaning method using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide bamboo charcoal particles which can improve bottom quality, water quality or soil quality by adsorbing and decomposing pollutants or by chemically reacting with the pollutants when a number of particles are provided to cover a polluted place of sea bottom, river bottom or soil; and to provide a sea bottom cleaning method using the same. <P>SOLUTION: The bamboo charcoal particles are obtained by charging sand, a bamboo charcoal powder, a binder and water into a granulator to cover the outer peripheral surface of each particle of the sand, as a nucleus, with a viscous mixture comprising the bamboo charcoal powder, the binder and water and to granulate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to bamboo charcoal particles that can purify the seabed and the like by covering them, and a seabed purifying method using the particles.

  Today, water pollution, soil pollution, and the like due to domestic wastewater, industrial wastewater, or industrial waste have become problems.

  As an example, in recent years, sediment and water quality have deteriorated in closed seas surrounded by land, and these have seriously affected the catch. For example, in a closed sea area that has many urban and rural areas in the vicinity, such as the Ariake Sea, pollutants contained in industrial wastewater, industrial waste, domestic wastewater, etc. tend to remain in the sea area, resulting in eutrophication. As a result, a large amount of microorganisms such as plankton causing red tide will be generated. In this way, water pollution is caused by the pollutant itself and the red tide.However, when such water pollution occurs, the flow of the sea stagnates, and sedimentary clay-like substances with a small particle size accumulate on the bottom of the sea. A so-called bottom sediment change occurs where the quality seabed becomes muddy.

  In addition, clay-like substances deposited on the sea floor contain a large amount of organic substances, and when such organic substances are oxidized and decomposed, nitric acid and organic acids are generated, so that the pH of seawater, which is inherently weakly alkaline, is acidic. The shift to the side has a serious impact on the fishery. In the Ariake Sea, the catch of bivalves has decreased significantly due to such changes in bottom sediment and water pollution, and the catch has fallen to about ¼ compared to the peak period around 1980.

  Based on such a current situation, conventionally, operations such as removal of clay-like substances accumulated on the seabed, supply of oxygen by cultivating the seabed, and laying of sea sand and mountain sand on the sea floor have been performed.

For example, the invention described in [Patent Document 1] is a material composed of a magnesium-based granular raw material, and collapses into fine particles when deposited in water and deposits on the seabed as sediment. In addition, it is a bottom sediment improving agent that is configured to improve water quality. According to this invention, the magnesium contained in the improving agent is combined with an acidic water pollutant to form a magnesium-based poorly soluble compound, so that the pH of water and bottom sediments shifted to the acidic side due to marine pollution or the like is originally obtained. Therefore, it is possible to improve water quality and bottom quality.
JP-A-9-239375

  However, the invention described in [Patent Document 1] has a problem in that the bottom sediment improving agent itself causes suspension of water quality when sprayed, which in turn causes deterioration of water quality. Moreover, since the poorly soluble compound formed by combining with water pollutants is deposited on the sea floor as it is, it is hardly a fundamental measure for improving the bottom sediment.

  As another problem, effective reuse of gypsum board, which is currently widely used as a building material, is being studied. Gypsum, the main raw material for gypsum board, is mainly composed of calcium sulfate, and the calcium sulfate generates hydrogen sulfide, which is a toxic gas, by the metabolism of sulfate-reducing bacteria that live in the groundwater etc. of waste treatment plants. In addition, due to the above reasons, when disposing of gypsum board that has become waste, a special facility is required to prevent the generation of such toxic gases, which requires significant costs for processing. Therefore, processing methods that do not turn into waste such as recycling are being studied.

  In view of these problems, the present invention uses bamboo charcoal particles and the same particles that can purify the bottom sediment, water quality, or soil by covering the contaminated sea bottom, river bottom, lake bottom or soil. The object is to provide a seabed purification method.

  In order to achieve the above object, the invention according to claim 1 mixes sand, bamboo charcoal powder, a binder and water and puts them in a granulator, and each particle of sand is used as a core, and bamboo charcoal powder on the outer peripheral surface thereof. It is characterized by being coated and granulated with a viscous mixture of binder and water.

  According to such a configuration, for example, when used for seabed purification, the sediment contained in the particles can change the sediment from mud to sandy, and at the same time, the bamboo charcoal powder can contaminate the seabed and seawater. Substances can be adsorbed and decomposed. In addition, such bamboo charcoal powder has a small specific gravity and cannot sink on the seabed alone, but it can be settled on the seabed due to the weight of the sand by combining them with sand particles with a large specific gravity and a binder. It was possible to use bamboo charcoal powder as seabed purification particles. Furthermore, by making it particulate, the surface area can be further increased, and the adsorption and decomposition ability of bamboo charcoal powder can be effectively exhibited.

  In the invention according to claim 2, the binder is one or more selected from calcium sulfate powder, cement, quicklime, lignin sulfite, bentonite, starch, molasses, and water glass. It is characterized by.

  According to such a configuration, sand and bamboo charcoal powder can be combined together. Furthermore, when calcium sulfate is used, not only this effect but also pH adjusted to the acidic side can be adjusted by combining calcium contained in the calcium sulfate with an acidic organic substance that is a contaminant. .

  The invention according to claim 3 is characterized in that the calcium sulfate powder is a gypsum powder recovered from a waste gypsum board.

  According to such a configuration, it is possible to effectively recycle waste gypsum board that has become a waste material that has been problematic in the past due to environmental problems due to toxic gas generated during processing and high processing costs to prevent the generation of this toxic gas. How to use can be provided.

  The invention described in claim 4 is characterized in that the bottom of the sea is purified by precipitating many bamboo charcoal particles according to claims 1 to 3 on the sea bottom.

  According to such a configuration, it is possible to provide a seabed purification method capable of improving the bottom sediment and the water quality by the effect of claim 1 by precipitating a large number of the same particles on the muddy seabed.

  According to the present invention, a large number of pollutants such as the seabed, riverbed or soil are covered to adsorb and decompose the pollutants, or cause chemical reactions with the pollutants, thereby improving the sediment and water quality or soil. It is possible to provide a bamboo charcoal particle capable of achieving the above and a seabed purification method using the same.

  Below, the Example at the time of using the bamboo charcoal particle concerning this invention as particle | grains for seabed purification is described.

  Bamboo charcoal particles according to the present example are granulated using a granulator with sand as the core of the particles, bamboo charcoal powder for purifying pollutants, and a binder and water for binding them together. It is obtained by this.

  In general, sand can be changed to sandy by covering the muddy substance deposited on the seabed. Sand used in the present embodiment can be mountain sand, sea sand or other sand, but it is preferable to use sand having a low clay component because the purpose is to change the sediment to sandy. . Further, as described later, since sand also serves as a weight for precipitating bamboo charcoal powder having a small specific gravity that cannot be submerged on the sea floor, in this embodiment, the specific gravity is higher. It is preferable to use large sand.

  Bamboo charcoal powder is a substance capable of adsorbing and decomposing pollutants in the sea and the seabed. Bamboo charcoal is widely known as a substance having a high purification ability, but it is said that the purification ability of such bamboo charcoal is due to the porous shape of the substance. That is, bamboo charcoal has a porous shape in which countless fine pores are formed as if bundled pipes, and can adsorb contaminants by intermolecular force generated by such pores. In addition, various microorganisms live in the pores of bamboo charcoal, and pollutants can be decomposed by the action of these microorganisms. In addition, microorganisms that inhabit the pores are classified according to the size of the pores, such as filamentous fungi for large pores, fungi for small pores, and bacteria for smaller pores. It is possible to form an optimal microbial flora for decomposing and metabolizing.

Moreover, although charcoal can be mentioned as a porous material having the same purification ability as bamboo charcoal, bamboo charcoal is generally said to have a larger specific surface area than charcoal and is about 200 to 300 m ² / g, and particles for submarine purification. It can be said that it is the best substance to use as Thus, the purification ability of bamboo charcoal is greatly influenced by its surface area, but in the present invention, in order to further increase the surface area of bamboo charcoal and further improve the purification ability, the bamboo charcoal is made into powder. It was.

  Bamboo charcoal is generally produced by heat-treating naturally dried bamboo using a clay pot, but it is known that the one that is slowly cooled after being carbonized at low temperature becomes more porous. Therefore, water purification ability can be further enhanced by using bamboo charcoal powder obtained by pulverizing and powdering bamboo charcoal produced by such a manufacturing method.

  Since the bamboo charcoal powder has a small specific gravity, it cannot be settled to the sea bottom even if it is introduced into the sea alone, and it floats on the sea surface or in the vicinity of the sea surface, so it cannot be used as particles for sea bottom purification. Therefore, in the present invention, the bamboo charcoal powder is precipitated on the seabed by the weight of the sand by combining the sand particles having a large specific gravity and the bamboo charcoal powder that are sedimentable on the seabed and using the binder and water. Made it possible.

  Binder and water are materials used to bind sand and bamboo charcoal powder together as described above. As the binder, one or more kinds selected from cement, quicklime, lignin sulfite, bentonite, starch, molasses, water glass or calcium sulfate, which are generally used as a granulating agent, are applied. Can be used.

  Below, the case where calcium sulfate is used as a binder is demonstrated.

The calcium sulfate powder according to this example is so-called hemihydrate gypsum (chemical formula CaSO ₄ · 1 / 2H ₂ O), and has a property of solidifying by a hydration reaction. For example, casts for fracture treatment and gypsum for molding using hemihydrate gypsum as a raw material are solidified by mixing powdered hemihydrate gypsum with water and causing a hydration reaction.

  Such calcium sulfate powder has a property as a binder, and at the same time, has the property of changing pollutants present in the seabed and sea to harmless substances through chemical bonds, thereby improving the bottom and water quality. be able to. Specifically, calcium contained in calcium sulfate chemically binds to acidic pollutants such as nitric acid and organic acids to form calcium-based poorly soluble compounds, thereby reducing the pH of seawater shifted to the acidic side. It returns to alkalinity. Thereby, it becomes possible to arrange the contaminated sea area into an environment in which fish and shellfish can easily inhabit, and can contribute to an increase in the catch.

  In this embodiment, the calcium sulfate powder is obtained from a gypsum board that has become a waste material. The gypsum board is configured by sandwiching a plate body made mainly of gypsum mainly composed of calcium sulfate between two thick sheets of paper or the like. Gypsum board is inexpensive but very strong, and is widely used as a building material on walls and floors.

  In the past, gypsum boards that became waste materials that were generated due to rebuilding of buildings were disposed of by incinerating only paper and reclaiming the gypsum part, but the reclaimed gypsum is sulfate that inhabits the groundwater in landfills. Since there is a possibility that hydrogen sulfide may be generated by the metabolism of reducing bacteria, which is an environmental problem, treatment using a special facility or the like has been performed. For this reason, disposal of gypsum board costs a lot of money, and a processing method that does not turn it into waste, such as recycling, is desired. Therefore, by using the gypsum board that has become such a waste material for the present bamboo charcoal particles, the cost for disposing the board becomes unnecessary, and the generation of hydrogen sulfide can be suppressed. Note that the paper separated from gypsum can be used as a water regulator for manure when producing compost from livestock manure.

When obtaining the calcium sulfate powder according to the present embodiment, that is, hemihydrate gypsum, from the waste gypsum board, firstly, the gypsum board is pulverized to separate the gypsum from the paper, and the separated paper is pulverized again. Thus, the gypsum adhering to the paper is removed, and the obtained gypsum is pulverized until it becomes powdery. The gypsum powder thus obtained is called dihydrate gypsum (chemical formula CaSO ₄ · 2H ₂ O) and does not have a solidifying action. Therefore, the gypsum powder is heat-treated at 160 to 170 ° C. to give half-hydrate gypsum. The calcium sulfate concerning a present Example can be obtained by passing through the process changed.

  When the bamboo charcoal particles according to the present embodiment use calcium sulfate as a binder, sand, bamboo charcoal powder, and calcium sulfate powder are mixed in a weight ratio of approximately 6: 2: 2, respectively. It is obtained by granulating with about 40% of water and granulating, and the outer peripheral surface is coated with a viscous mixture of bamboo charcoal powder, calcium sulfate powder and water with each particle of sand as the core. It is configured as follows.

  Since the substance thus obtained is in the form of particles, it can uniformly cover the muddy seabed. In addition, when comparing the water purification ability of particles granulated by a granulator as in this example and a mere solid that has not been granulated, the particles have a larger surface area than solids and contact with pollutants. Since the frequency is high, it can be said that the water purification ability is higher than that in the solid state. Furthermore, since the particles according to this example are formed using sand particles as the core, the particle size is small, and furthermore, each particle itself is porous and has a very large surface area. The purification function of the powder can be exhibited more effectively.

  In addition, since the particle size of the present particle can be freely changed by using a granulator, for example, when covering the particle in a place where the tide is fast, the particle is scattered by the ocean current. To prevent this, the particle size can be increased.

  Next, a seabed purification method using bamboo charcoal particles using calcium sulfate as a binder will be described.

  Bamboo charcoal particles according to the present invention are added to natural sand such as mountain sand and sea sand at a ratio of about 20%, and then dropped from the ship, so that they are laid on the seabed that has changed to muddy. .

  Natural sand and this particle laid on the seabed cover mud substances deposited on the seabed to change the sediment to sandy, making it easy for inhabitants to live on the seafloor, such as clams, monkeys, and tailfish. Can be formed. In addition, by blocking the contact between the muddy seabed and seawater, it is possible to prevent the phosphate and nitrogen compounds that cause water quality deterioration from being dissolved in the sea from the organic matter contained in the muddy substance, There is also an effect of reducing the consumption of dissolved oxygen by these organic compounds and preparing an environment in which living organisms inhabiting the seabed and sea can easily live. In addition, marine organisms with increased numbers of prey due to such effects prey on suspended nitrogen in water such as plankton, thereby further improving the marine environment.

  Bamboo charcoal particles according to the present embodiment can adsorb and decompose pollutants existing in the sea floor and sea by the bamboo charcoal powder contained in the particles. Such purification ability is more effectively exhibited by the porous property of the particles.

  In addition, after the particles are covered on the seabed, calcium sulfate is gradually separated from the surface by being affected by seawater and ocean currents. Furthermore, the bamboo charcoal powder combined with the sand by the calcium sulfate is separated from the particles in the same manner as the calcium sulfate, and the bamboo charcoal powder and the calcium sulfate powder are floated or dissolved in the sea. Due to the separating action of the bamboo charcoal powder and calcium sulfate powder, the particles can purify pollutants not only near the sea floor but also over a wide range in the sea.

  Since the solubility of calcium sulfate in seawater is very low, separation of the calcium sulfate powder and bamboo charcoal powder from the main particles as described above is performed very slowly. Therefore, there is no fear that an abrupt environmental change occurs due to such a separation action, and furthermore, the effect of the present particles can be sustained for a long time. Moreover, since the solubility of this calcium sulfate powder becomes the highest in 20-40 degree | times where microorganisms propagate easily, the elution amount to the sea can be adjusted according to the number of microorganisms living.

  In addition, the bamboo charcoal powder according to the present example is stirred in the seabed by the tide, so that many pollutants come into contact with the bamboo charcoal powder and the calcium sulfate powder, and the purification ability of these powders is effective. Can be demonstrated.

  The preferred embodiments of the present invention have been described above. However, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

  Bamboo charcoal particles according to the present invention are not only used for the purification of the seabed as in the above-described embodiment, but also, for example, by purifying these bottoms and water by covering them on rivers and lakes, etc. By using it, soil purification and pH adjustment can be performed.

Claims (4)

Sand, bamboo charcoal powder, binder and water are mixed and put into a granulator,
Bamboo charcoal particles characterized in that each particle of sand is used as a core and granulated by coating the outer peripheral surface with a viscous mixture of bamboo charcoal powder, binder and water.   2. The binder according to claim 1, wherein any one or more selected from calcium sulfate powder, cement, quicklime, lignin sulfite, bentonite, starch, molasses, and water glass are applied. Bamboo charcoal particles as described.   Bamboo charcoal particles according to claim 1 or 2, wherein the calcium sulfate powder is a gypsum powder recovered from a gypsum board as a waste material.   A method of purifying the seabed, comprising purifying the seabed by depositing a large number of bamboo charcoal particles according to claim 1 on the seabed.