JP5008184B2 - Sludge purification civil engineering method - Google Patents

Description

The present invention relates to a civil engineering method using a purification material suitable for protecting the natural environment.

  In recent years, many civil engineering techniques for protecting the natural environment have been proposed, such as purification of soil and river pollution and mitigation of the heat island phenomenon. For example, the inventor of the present application disclosed a technique for purifying soil, rivers, and the like using a purification material containing carbide in Patent Document 1, and a method for melting snow using a snow melting pavement material containing a carbon material in Patent Document 2. The technology to perform, or the technology which uses it for the pavement in the summer and controls the temperature rise of the pavement is proposed.

JP 2002-52339 A JP 2003-328503 A

  By the way, what is described in Patent Documents 1 and 2 is a block containing carbide or the like, and is not an aggregate of granular carbide or the like. Therefore, if the carbide or the like is made granular, the purification material or the like can be packed in a bag, and the purification material or the like can be spread in a necessary amount. However, granular carbides and the like are easily dissipated by rainwater, wind, and the like, and it has been difficult to obtain the effect for a long time after being spread.

  The present invention has been made in view of such reasons, and an object of the present invention is to provide a purification material containing granular carbides that is difficult to dissipate due to rainwater, wind, and the like. It is providing the civil engineering method applied to the civil engineering technology which protects.

In order to achieve the above object, the present invention is a sludge purification civil engineering method, which is a purification material obtained by mixing granular carbide and granular blast furnace slag at a weight ratio of 5:95 to 50:50 to form a granular aggregate. Is spread over the surface of sludge accumulated at the bottom of the ocean, lakes or rivers with a predetermined thickness.

According to sludge purification civil method of the present invention, it is possible to perform the purification of the sludge by the granular carbides contained in the purification material, moreover, since the granular carbides are mixed with granulated blast-furnace slag, the granular carbides such as flow of water Therefore, it is difficult to dissipate and the effects can be obtained for a long time.

  The best mode for carrying out the present invention will be described below with reference to the drawings. First, the purification material 1 which concerns on embodiment of this invention is demonstrated. FIG. 1 is a cross-sectional view of the purification material 1. The purification material 1 is a granular aggregate obtained by mixing granular carbide 11 and granular blast furnace slag 12 at a weight ratio of 5:95 to 50:50. As the ratio of the particulate carbide 11 increases, the purification material 1 has higher ability to adsorb harmful substances, support microorganisms, and retain water, as will be described in detail later. On the other hand, the purification material 1 is dissipated by rainwater or wind. It becomes easy. Therefore, in the civil engineering methods A to D described later using the purification material 1, it is desirable to keep the weight ratio of the granular carbide 11 and the granular blast furnace slag 12 in the above range.

  The granular carbide 11 is obtained by pulverizing a carbide obtained by heating in a state deficient in oxygen in accordance with a normal charcoal baking process, and the shape thereof is rugged and is angular. In this embodiment, the particle size (size) is set to about 1 to 20 mm so as to be well mixed with the granular blast furnace slag 12 described later. The granular carbide 11 is, for example, charcoal, bamboo charcoal, RDF carbide, sludge carbide, etc., and is porous with a large number of pores on the surface and inside. These numerous holes can adsorb harmful substances and odors and retain water, and the holes can carry microorganisms well because there are few environmental changes.

The granular carbide contains ash. Ash refers to an incombustible inorganic substance that remains even if the object burns out, that is, nitrogen, phosphoric acid, potassium, calcium, and the like. Charcoal and bamboo charcoal usually contain as much as several percent by weight of ash. RDF carbide is obtained by carbonizing RDF (Refuse Derived Fuel), which is a solid fuel made from combustible garbage from homes, at a high temperature (usually 800 to 850 ° C.). Contains the above ash. The sludge carbide is obtained by reducing the moisture of sludge accumulated in the bottom of uncontaminated sewers to about 30% by weight or less and carbonizing it at a high temperature (usually 800 to 850 ° C.). Contains the above ash. Specifically, the ash content of cedar, carbon, and RDF carbonized at 850 ° C. was measured to be 2.3 wt%, 3.3 wt%, and 35.7 wt%, respectively. Moreover, when the total amount of nitrogen, phosphoric acid, and potassium was measured with two samples of sludge carbides, they were 18.8 wt% and 21.8 wt%.

As carbides, generally, the one with less ash content is considered to be of higher quality. However, according to the experimental results shown in Table 1, for example, the RDF carbide and the sludge carbide with more ash content are more charcoal, bamboo charcoal. It is thought that the propagation of microorganisms is better than that. The experimental results in Table 1 are the results of investigating changes in BOD (unit: mg / l) by contacting 10 kg of charcoal or charcoal of RDF with water of 0.069 m ³ of the reclaimed land.

  The experimental results in Table 1 show that RDF carbides have more ash, so that microorganisms are easier to propagate than charcoal, and therefore RDF carbides are purified more than charcoal. Therefore, from the viewpoint of supporting microorganisms, RDF carbide and sludge carbide are more preferable than charcoal, bamboo charcoal, and the like. As will be described later, the granular blast furnace slag 12 contains lime and the like, but it can also be expected that these components assist the propagation of microorganisms carried on the granular carbide 11.

  The granular blast furnace slag 12 is obtained by cooling the molten slag generated together with pig iron in the blast furnace and adjusting the particle size, and the shape thereof is sharply uneven and angular, and the surface is rough. The particle size (size) of the granular blast furnace slag 12 used for the purification material 1 is a size according to the particle size of the granular carbide 11 described above, and is about 1 to 20 mm in this embodiment. Further, it has a certain number of holes on the surface and inside.

  The granular blast furnace slag 12 has a chemical composition mainly composed of lime (CaO) and silica (SiO 2), and has a specific gravity larger and harder than the granular carbide 11. And when it contacts moisture, lime and silica elute in a very small amount to form a hydrate, so that the granular blast furnace slags 12 are bonded together in some places.

  For example, when the purification material 1 formed by mixing granular carbide 11 and granular blast furnace slag 12 in a predetermined weight ratio to form a granular aggregate is spread on the surface of soil, the granular carbide 11 is pressed against the heavy granular blast furnace slag 12. In other words, it is difficult to physically dissipate by being fitted or engaged with the irregularities of the granular blast furnace slag 12. Further, when water is intentionally added by rain water or the like, the granular carbide 11 sandwiched between the granular blast furnace slag 12 is more difficult to dissipate. More specifically, when the spread purification material 1 is exposed to the wind, a part of the granular carbide 11 is suppressed from becoming dust, and when a person or an object touches the purification material 1, the granular carbide It is suppressed that a part of 11 adheres. Further, when the purification material 1 is exposed to water such as rain water, it is due to the fact that rain water or the like passes through the granular blast furnace slag 12 and the flow does not concentrate on the granular carbide 11 due to the above physical force. The granular carbide 11 is suppressed from flowing out. Moreover, even if the purification material 1 is touched during civil engineering work, the hands and the like are hardly stained black by the granular carbide 11.

  Moreover, although the granular carbide | carbonized_material 11 shows alkalinity, by mixing with the granular blast furnace slag 12, alkalinity is reduced and it becomes easy to become weak alkalinity. Therefore, it will be in the state where microorganisms can reproduce more.

  The granular blast furnace slag 12 constituting the purification material 1 is a by-product in the blast furnace and is produced in a large amount and can satisfy various safety standards, but currently has few applications. Therefore, it is available at a very low price, and its use also contributes to solving the waste problem and reducing waste of resources. Further, if RDF carbide or sludge carbide is used for the particulate carbide 11 constituting the purification material 1, this also reduces the cost, which contributes to the solution of the dust problem and the reduction of waste of resources.

Next, a civil engineering method A for purifying soil, which is a reference embodiment of a civil engineering method using the purification material 1, will be described. FIG. 2 is a cross-sectional view showing the civil engineering structure obtained by the civil engineering method A. In the civil engineering method A, first, purification holes 21, 21... Having a predetermined depth are dug at predetermined intervals in the soil 2 contaminated with harmful substances. The purification hole 21 of this embodiment is a columnar or prismatic shape with a diameter of 30 cm and a depth of 10 m, and the interval is 5 m. Next, the purification material 1 is embedded in the purification holes 21, 21. Then, the purification material 1 is spread on the surface of the soil 2 with a predetermined thickness. The spread thickness of this embodiment is 30 cm.

In the civil structure by this civil engineering method A, harmful substances in the soil 2 (for example, heavy metals such as organic chlorine compounds , dioxins, arsenic and lead) are dissolved by rainwater and move to the surface of the soil 2 and the purification hole 21. In the purification material 1 and the purification hole 21 laid down on the surface of the soil 2 with a predetermined thickness, harmful substances are adsorbed by the granular carbides 11 and partly decomposed into harmless substances by microorganisms carried by the granular carbides 11. The Further, when harmful gases and odors are generated from harmful substances in the soil 2, they are adsorbed by the particulate carbide 11 of the purification material 1 on the surface of the soil 2 before being diffused into the atmosphere. Part of the adsorbed harmful gas and odor is decomposed into harmless or odorless substances by microorganisms carried by the particulate carbide 11.

  In this way, the soil 2 contaminated with harmful substances is purified by the purification material 1 spread on the surface of the soil 2 with a predetermined thickness and the purification material 1 embedded in the purification hole 21. Since the granular carbide 11 is difficult to dissipate due to rain water or wind as described above, the effect can be obtained for a long time.

  In addition, since various microorganisms inhabit in soil 2, some microorganisms including what decomposes | disassembles a harmful substance propagate in the granular carbide | carbonized_material 11 which is an environment which is easy to reproduce. In addition to these, special microorganisms may be planted. In particular, the deep part of the purification hole 21 (for example, 5 m or more underground) is easily deficient in oxygen, so aerobic microorganisms are difficult to inhabit. However, if a facultative anaerobic microorganism that decomposes harmful substances is specifically injected, the purification effect Will increase. Among such facultative anaerobic microorganisms, those that are weakly alkaline and more proliferate are known, and are suitable for the purification material 1 that easily exhibits weak alkalinity as described above. When the microorganisms change generations, the dead bodies of the microorganisms generate odors, but the odors are trapped in the granular carbide 11. As microorganisms injected into the purification material 1, Empedobacter genus bacteria described in International Publication WO2006 / 011416A1 are possible.

  In addition, a plant growth promoter (for example, manufactured by Manda Fermentation Co., Ltd.) can be injected into the granular carbide 11 to promote the growth of microorganisms.

  Further, preferably, in order to enhance the purification effect, mushrooms are planted on the purification material 1 spread with a predetermined thickness on the surface of the soil 2 after or during purification. Mushrooms can grow and grow hyphae on granular carbides 11 and then suck up harmful substances. Mushrooms can also decompose harmful substances.

  Moreover, you may plant a herb instead of or in addition to a mushroom. For example, Iwadaresou (variety registration application numbers: 18591 and 18592), which does not produce seeds by breed improvement, is preferably used. Herbs such as Iwadareso have roots in the purification material 1 and penetrate the purification material 1 to deepen the roots deep in the soil 2 (for example, 50 cm), so that harmful substances are sucked up. To prevent dissipation. Moreover, since Iwadareso can be planted widely from acidity to alkalinity, it can also be planted on the purification material 1 that easily exhibits weak alkalinity. In addition, there is a possibility that ethanol can be extracted from the collected Iwadaresou and used as fuel.

Next, a civil engineering method A ′, which is a modification of the above-described reference embodiment, will be described. In this civil engineering method A ′, the purification material 1 is spread on the surface of the soil 2 contaminated with harmful substances with a predetermined thickness (for example, 30 cm), and a liquid vegetable oil emulsion is spread over the surface at a predetermined interval (for example, an interval of 1.5 m). ). In addition, although the holes 21 for purification | cleaning 21 of civil engineering method A (FIG. 2) may be provided, it is not necessarily required.

  The vegetable oil emulsion is an emulsion obtained by adding a highly safe vegetable oil (for example, soybean oil) as a main raw material (for example, 60%) and adding other substances (for example, lactate, etc.), and is diluted with water. The vegetable oil emulsion diffuses in the soil 2 and penetrates to a depth of about 30 to 40 m. Thereby, the soil 2 changes to an anaerobic environment, and the anaerobic microorganisms in the soil 2 are activated. Vegetable oil produces hydrogen by anaerobic microorganisms, and harmful substances are decomposed into harmless substances by their reducing and dechlorinating actions. As the vegetable oil emulsion, for example, a vegetable oil emulsion (US Pat. No. 6,398,960) manufactured by EOS Remediation can be used. This vegetable oil emulsion has a particle size smaller than 1 μm and is stable in an emulsified state for a long time.

  The purification material 1 is the same as that used in the civil engineering method A. The granular carbide 11 adsorbs harmful gases and odors from harmful substances, preserves the vegetable oil emulsion, and gradually exudes to the soil 2 to maintain the effect of the vegetable oil emulsion in the soil 2 for a long time. it can. Moreover, the anaerobic microorganisms (especially facultative anaerobic microorganisms) carried on the particulate carbide 11 that is an environment in which microorganisms are easy to propagate diffuse deeply into the soil 2 in which the vegetable oil emulsion has diffused, thereby anaerobic in the soil 2. The amount of sex microorganisms can be maintained. Furthermore, it is desirable that the particulate carbide 11 of the purification material 1 is preliminarily planted with facultative anaerobic microorganisms (for example, the above-mentioned Empedobacter genus bacteria). Then, the facultative anaerobic microorganisms carried on the particulate carbide 11 are diffused together with the vegetable oil emulsion, and the harmful substances in the soil 2 are rapidly decomposed.

  In this way, the soil 2 contaminated with the harmful substances is purified by the purification material 1 spread on the surface of the soil 2 with a predetermined thickness and the vegetable oil emulsion injected thereon. In the civil engineering method A ′, harmful substances in the soil 2 are decomposed even on the spot. The civil engineering method A ′ is used independently or simultaneously with the civil engineering method A depending on the specific state of the soil 2.

Next, a civil engineering method B for purifying sludge, which is an embodiment of the civil engineering method using the purification material 1, will be described. 3 is a cross-sectional view showing a civil engineering structure obtained by the civil engineering method B. FIG. In this civil engineering method B, the purification material 1 is spread with a predetermined thickness on the surface of the sludge 3 accumulated at the bottom of the ocean, lakes or rivers and contaminated with harmful substances. That is, the surface of the sludge 3 is covered with the purification material 1. In this case, the thickness of the purifier 1 is determined according to the amount and quality of the sludge 3, but the uniformity may be rougher than the civil engineering method A which is the reference embodiment .

  Hazardous substances in the sludge 3 and harmful gases generated therefrom are adsorbed by the particulate carbide 11 of the purification material 1 spread with a predetermined thickness on the surface of the sludge 3 before diffusing into water such as the ocean. Part of the adsorbed harmful substances and the like is decomposed by microorganisms carried by the particulate carbide 11. Thus, the sludge 3 contaminated with harmful substances is purified by the purification material 1. Since the granular carbide 11 is difficult to dissipate due to the flow of water as described above, the effect can be obtained for a long time.

Next, a civil engineering method C for retaining water on a paved road, which is another embodiment of the civil engineering method using the purification material 1, will be described. FIG. 4 is a cross-sectional view showing the civil structure obtained by the civil engineering method C. As shown in FIG. 4, the purification material 1 is spread on the surface of a road base (not shown) with a predetermined thickness, and a pavement 4 such as concrete or asphalt is laid on the purification material 1. The pavement 4 has water permeability that can pass rainwater and the like. The thickness of the purification material 1 of this embodiment is 2 to 10 cm.

  Moisture such as rainwater that has permeated through the pavement 4 is retained in the granular carbides 11 of the purifying material 1 spread on the surface of the road base with a predetermined thickness. By this water retention, the heat island phenomenon can be alleviated by suppressing the temperature rise of the pavement 4 in the summer, that is, the pavement. That is, according to this embodiment, there is an effect different from the purification of soil and sludge as in the previous embodiment. Since the granular carbide 11 is difficult to dissipate due to the flow of moisture as described above, the effect can be obtained for a long time.

Next, a civil engineering method D for melting snow, which is still another reference embodiment of the civil engineering method using the purification material 1, will be described. FIG. 5 is a cross-sectional view showing the snow cover 5 and the purification material 1 obtained by the civil engineering method D. As shown in FIG. 5, a predetermined amount of the purification material 1 is removed on the surface of the snow cover 5 on a road or the like. The amount of the purifying material 1 to be distributed in this case is determined according to the amount of snow 5, but the uniformity is rougher than the civil engineering method A which is the reference embodiment and the civil engineering method C which is another reference embodiment. It may be. The purifying material 1 is more effective when spread after being warmed at a high temperature.

  The purification material 1 with a predetermined amount removed on the surface of the snow cover 5 is warmer than the snow cover portion, and the snow is in the vicinity of the purification material 1 due to the heat of the entire purification material 1 and far infrared rays emitted from the granular carbides 11. Melts out. A part of the water content of the melted snow is absorbed by the granular carbide 11, so that the snow around the melted snow immediately melts. In addition, if the purifying material 1 is distributed in advance before snow is accumulated, snow and freezing hardly occur due to far infrared rays. That is, according to this embodiment, there is an effect different from the purification of soil and sludge as in the previous embodiment. As described above, the granular carbide 11 is difficult to dissipate due to the flow of melted snow moisture, so that the effect can be achieved for a long period of time. Further, the road can be prevented from being black and dirty. Further, since the granular blast furnace slag 12 is hard and the unevenness is greatly changed, the purification material 1 has a great effect of preventing slippage.

  The purifying material 1 may be mixed with a granular heat-generating material of an existing snow melting agent, for example, calcium chloride and distributed. Since calcium chloride may adversely affect vehicles and plants, the amount of calcium chloride can be reduced by using it together with the purification material 1.

The purification material 1 according to the embodiment of the present invention and the civil engineering methods A, A ′, B, C, and D using the same have been described above. The civil engineering methods A, A ′, B, C, and D are civil engineering techniques suitable for protecting the natural environment, and can be effective for a long time.

  The present invention is not limited to the one described in the embodiment, and the design can be changed within the scope of the matters described in the claims. For example, other materials not described in the embodiment can be contained, and it is needless to say that specific numerical values can be changed according to environmental conditions.

It is sectional drawing of the purification material which concerns on embodiment of this invention. It is sectional drawing which shows embodiment of reference of the civil engineering method using the purification material same as the above. It is sectional drawing which shows embodiment of this invention of the civil engineering method using the purification material same as the above. It is sectional drawing which shows another reference embodiment of the civil engineering method using the purification material same as the above. It is sectional drawing which shows another reference embodiment of the civil engineering method using the purification material same as the above.

DESCRIPTION OF SYMBOLS 1 Purification material 11 Granular carbide 12 Granular blast furnace slag 2 Soil 21 Hole for purification 3 Sludge (sludge)
4 Pavement 5 Snow cover

Claims (1)

A purification material made by mixing granular carbide and granular blast furnace slag at a weight ratio of 5:95 to 50:50 into a granular aggregate is applied to the surface of sludge accumulated at the bottom of the ocean, lakes or rivers at a predetermined thickness. A sludge purification civil engineering method characterized by laying down.

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