JP2012183526A - Method for improving contaminated soil, contaminated soil improving agent, and concrete product using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contaminant eluting method for eluting contaminants by adsorbing the contaminants included in soil or the like with the powder or granules of shells and zeolite, and insolubilizing the contaminants to the outside.SOLUTION: A contaminated soil improving agent is obtained by admixing the powder or granules of shells and the powder or granules of zeolite, and if necessary, admixing the powder or granules of bamboo charcoal and/or the squeezed juice of peels of citrus fruits or the low temperature dried powder of the peels of citrus fruits therein. Contaminated soil is admixed with such a contaminated soil improving agent. By using the contaminated soil improving agent, the elution of contaminants from the contaminated soil can be suppressed. By admixing the contaminated soil with the contaminated soil improving agent and mixing cement therein, a concrete product in which the contaminants are not eluted can be produced.

Description

  The present invention relates to a contaminated soil improving method, a contaminated soil improving agent, and a concrete product using the same, which suppresses elution of soil pollutants using shellfish and zeolite powders or granules.

Conventionally, Japanese Unexamined Patent Application Publication No. 2009-39616 adds a shell and its crushed material to the soil in order to improve the growth of microorganisms that decompose pollutant organic compounds present in the soil as a structure for improving the soil using shells. The structure to perform is disclosed.
However, shellfish originally ingest a trace amount of heavy metals dissolved in seawater, and have a mechanism that holds heavy metals with an alkyl group of about 10 PPM in the body and discharges them from the sea, and is contained in shells. The adsorbed components adsorb heavy metals to insolubilize them, and have a property of producing a binding force.
On the other hand, in Japanese Patent Application Laid-Open No. 2005-254723, a shell-mixed concrete using a crushed shell as a part of a fine aggregate is known, but this is only a use of a crushed shell instead of a fine aggregate. No consideration is given to the function of preventing contaminant elution.
In addition, zeolite has a porous structure, has an adsorption function, an ion exchange function, and a catalytic function, has a higher liquid absorption rate than the crushed shell material, and crushed the shell and transported to the site. It can be obtained at a lower price.

JP 2009-39616 A JP 2005-254723 A

The present invention has been devised in view of the above circumstances, and its main problem is that a mixture of shell powder or granule and zeolite powder or granule is used as a contaminant and liquid in soil. To provide a contaminated soil improving method or a contaminated soil improving agent that can be adsorbed mainly by zeolite powder or granules, and otherwise adsorbed by shell powder or granules or the remaining zeolite powder or granules and insolubilized. It is in.
Another object of the present invention is to mix bamboo charcoal powder or granule in addition to shellfish and zeolite powder or granule to remove malodor, and citrus fruit peel or dried to be mixed with cement. The object is to provide a contaminated soil conditioner mixed with powder.
Another object of the present invention is to provide a concrete product in which contaminated soil and the contaminated soil improver are mixed into cement to suppress the elution of the pollutant.

In order to solve the above problems, the present invention provides a soil improvement method according to claim 1,
A contaminated soil containing a pollutant is mixed with a contaminated soil conditioner composed of a mixture of shell powder or granule and zeolite powder or granule.
In the invention of claim 2,
Bamboo charcoal powder or granules are mixed with the contaminated soil conditioner.
In the invention of claim 3,
The squeezed juice of citrus fruit or a low-temperature dry powder of citrus fruit peel is mixed with the contaminated soil conditioner.
In the invention of claim 4,
A soil improvement accelerator such as a nitrogen compound or an inorganic phosphorus compound is mixed with the contaminated soil improver.
In the invention of the contaminated soil conditioner of claim 5,
It consists of the contaminated soil improvement agent in any one of Claim 1 to 4.
In the invention of the concrete product of claim 6,
The contaminated soil conditioner according to claim 5 is mixed with contaminated soil, mixed with cement and molded.
In the invention of claim 7,
The contaminated soil is characterized by comprising dried sludge soil, or soil mixed with pulverized industrial waste or incinerated ash.

Powders and granules obtained by crushing scallops and other shells can adsorb contaminants in the crystals and confine them in the crystals.
In addition, the shell components have the property of adsorbing heavy metals to insolubilize them and producing binding forces.
Zeolite powders and granules have an adsorption function, an ion exchange function, and a catalytic ability, and the ability to adsorb contaminants is similar to that of shellfish powders and granules.
Furthermore, since the zeolite powder and granules have a higher liquid absorption rate than the shell powder and granules, the liquid containing the pollutant can be absorbed in a large amount more efficiently than the shell powder and granules.
Therefore, by mixing shell powder and zeolite powder or granule and using it as a soil improver, it is possible to improve the soil by adsorbing and insolubilizing pollutants in the shell or zeolite powder or granule.
Zeolite powder or granules are slightly less expensive than shell powder or granules, which are free of raw material costs and costly for crushing, and have a high liquid absorption rate, so it is economical to use shell powder and zeolite powder or granules. Excellent in efficiency and efficiency.
Furthermore, malodor can be absorbed by mixing bamboo charcoal powder or granules.
When mixing soil pollutants with cement, add citrus peel or low-temperature dry powder of citrus peel to adjust the pH to an environment where the components in the shell are easy to function with antibacterial properties. can do.
By mixing these with cement to obtain a concrete product, a product having a soil improvement effect can be obtained.
Moreover, when waste, incineration ash, etc. are included in concrete, the elution to the exterior of the contaminant from these can be suppressed.

It is a block diagram which shows an example of the manufacturing method of the soil improvement agent of Example 1. FIG. It is an analysis table | surface which shows purification of river sludge. It is an analysis table | surface which shows purification | cleaning of dry matter. It is an analysis table | surface which shows purification | cleaning of incineration ash. 6 is a block diagram of Embodiment 2. FIG. 10 is a block diagram of Example 3. FIG. FIG. 10 is a block diagram of Example 4. 10 is a block diagram of Embodiment 5. FIG. FIG. 10 is a block diagram of Example 6. 10 is a block diagram showing a manufacturing method of Example 6. FIG. It is a block diagram which shows commercialization of FIG.

  Hereinafter, a preferred embodiment in which scallops are used as an example of shells as the soil conditioner of the present invention will be described with reference to the drawings.

The soil conditioner of Example 1 uses crushed scallop shell powder 1A and zeolite powder 1B mixed in substantially the same ratio.
Here, as shown in FIG. 1, the shell powder 1 </ b> A is thrown into a hopper 11, transferred by a conveyor, and crushed by a crusher 12.
The crushed shells are transferred by a conveyor and sorted by the vibrating screen 13 to collect shell powder 1A of 15 mm or less.
Shell powder exceeding 15 mm is again returned to the crusher 12 and crushed, and those having a diameter of 15 mm or less are selected by the vibrating screen 13 and the above procedure is repeated.

The mixed powder 1 of the shell powder 1A and the zeolite powder 1B obtained as described above is charged or spread on the soil to be improved. You may mix with soil as needed.
The amount to be added is increased or decreased according to the soil contamination status, but it is preferable to add an amount corresponding to half or more of the weight of the soil.
Further, the mixing ratio of the shell powder 1A and the zeolite powder 1B is 1: 1, but when the water content of the contaminated soil is high, the ratio of the zeolite powder 1B is adjusted, and when the water content is low, the ratio of the zeolite powder 1B is set. It is good also as a mixed powder of a ratio suitably according to the condition of contaminated soil.

For a 1 kg sample of contaminated soil, 500 g of the mixed powder is added and mixed with a mixer, and the numerical value of the pollution improvement result is measured.
If insufficient, increase in 100g increments and measure until contamination improvement is acceptable.
Based on the above experimental values, the mixing ratio of the mixed powder to the contaminated soil is determined, and the soil is improved.
It is considered that the mixed powder 1 can enclose harmful substances in the pores by applying the property that homogeneous molecules attract each other.
As a result, contaminants such as heavy metals and environmental hormones in the soil can be adsorbed to the shell powder 1A and the zeolite powder 1B, thereby making them harmless.

Fig. 2 shows the effect of river sludge improvement in river bottom sediment improvement and purification work.
In addition, FIG. 3 shows the effect of improving dry matter (sludge removed from the seabed and dried in the sun).
Fig. 4 shows the effect of improving municipal waste incineration ash.
As a result of the dissolution test, both PCDD3 and PCDF3 are 0.02mg / L or less in the shell powder processed.
Therefore, the soil subjected to the shell powder treatment can prevent soil contamination of sewers, rivers, seas (ports, bays, etc.), and groundwater contamination due to soil contamination of factory sites and the like.

In addition to the mixed powder 1 of Example 1, the soil improver of Example 2 can improve the soil improvement effect by using the citrus peel 2 in combination (see FIG. 5).
The organic matter contained in the citrus peel 2 can slowly detoxify and sterilize the contaminants at room temperature.
Moreover, the pH of the soil can be adjusted so that the shell powder treatment is appropriate.
Instead of or together with the citrus peel juice 2, a low-temperature dry powder of citrus peel may be used.

In this method, the peel of citrus fruits is dried and powdered by using a low-temperature dryer and setting the humidity to about 70%.
The low-temperature dry powder of citrus peel is preferably used for contaminated soil that does not require water.
The citrus peel 2 and the low-temperature dry powder of citrus peel have the same weight as the shell powder.
In Example 2, it was confirmed that the effect of contamination purification can be enhanced compared to Example 1.

The citrus peel juice 2 used here is preferably approximately the same weight as the mixed powder 1 used, but is not particularly limited.
The method of use may be a method in which the mixed powder 1 is immersed in the juice 2 and sprayed on the soil at the same time. Alternatively, the mixed powder 1 and the juice 2 are separately added to the soil and sprayed simultaneously or separately. It may be a thing.

The soil conditioner of Example 3 is composed of a mixture of bamboo charcoal fragments 3 planted with lactic acid bacteria in the above example (see FIG. 6).
As an example, lactic acid bacteria are grown by planting lactic acid bacteria on a bed with a thickness of about 500 mm.
The lactic acid bacterium may be a fermented soybean lactic acid bacterium, or a certain kind of lactic acid bacterium in the soil.

The broken pieces 3 of bamboo charcoal are cut into a suitable length (for example, 1 m) and then baked in a charcoal kettle through a knot hole, and the baked bamboo charcoal is cut to a length of about 50 mm.
The bamboo charcoal is laid so as to be arranged between the bed where the lactic acid bacteria are planted, and heat is applied, and the lactic acid bacteria are propagated in the bamboo charcoal cells by fermentation.

The bamboo charcoal in which the lactic acid bacteria are planted is further broken into pieces and crushed to the size of sand grains to complete a broken piece 3 of bamboo charcoal in which the lactic acid bacteria are planted.
The bamboo charcoal fragments 3 are preferably used in substantially the same amount as the mixed powder 1, but can be appropriately increased or decreased depending on the state of bad odor of the soil.

The bamboo charcoal fragments 3 planted with the lactic acid bacteria are mixed with the mixed powder 1 and the citrus peel 2 and used as a soil improver.
Alternatively, these may be used separately, the bamboo charcoal fragments 3 and the mixed powder 1 may be mixed, and the juice 2 may be used separately.
The usage is mixed into the soil in the same way as shellfish powder, and used after stirring.
In Example 3, it was confirmed that the effects of contamination purification and odor prevention can be enhanced as compared with Example 2.

In order to increase these synergistic effects, in particular, the mixed powder 1 and the broken pieces 3 of bamboo charcoal planted with lactic acid bacteria are placed in a predetermined position in the soil so as not to dissipate in the soil. It is preferable to dispose and squeezed juice 2 of citrus peel to the position.
Lactic acid bacteria use lactic acid bacteria that weaken the toxicity of certain substances or deodorize bad odors, so that they can continue to grow in countless vesicles of bamboo charcoal, and can withstand long-term use.
At this time, the pH of the juice 2 can be adjusted to adjust the growth environment for lactic acid bacteria.

Commercially available soil improvers (improvement promoters) 4 may be added to the soil improvers of Examples 1 to 3 (see FIG. 7).
For example, a known soil improver or improvement accelerator such as a nitrogen compound or an inorganic phosphorus compound is added as the soil improver 4.
Examples of the nitrogen compound include ammonium chloride, ammonium sulfate, and ammonium phosphate. Examples of the inorganic phosphorus compound that can be used include ammonium phosphate, dipotassium hydrogen phosphate, and potassium dihydrogen phosphate. The soil improver and the improvement accelerator can be used.
Thereby, the shortage of the mixed powder 1, the squeezed juice 2, and the bamboo charcoal fragments can be compensated, or the purification effect can be improved.

The soil improvement agents of Examples 1 to 4 can be mixed with cement 5 to make a concrete product 6 having a soil improvement effect (see FIG. 8).
That is, mixed powder 1, citrus peel 2, bamboo charcoal fragment 3 planted with lactic acid bacteria, soil improver 4, etc. can be mixed into cement 5 to produce concrete product 6 having a desired shape. .

  It is preferable that the ratio of the mixed powder 1 mixed with the cement 5 and the broken piece 3 of bamboo charcoal in which lactic acid bacteria are planted is substantially equal. The number can be increased or decreased as appropriate.

The concrete product 6 can purify pollutants contained in the water by passing sewage, river water, sea water, and the like through the inside.
The concrete product 6 is manufactured by a known concrete manufacturing method excluding the mixing of the industrial waste pulverized product and the incinerated ash of Example 6, and the description thereof will be omitted.

Moreover, you may use for the said concrete product 6 mixing the waste which dried the said contaminated soil with cement.
The concrete product 6 contains all or part of the mixed powder 1, citrus peel 2, bamboo charcoal fragments 3 planted with lactic acid bacteria, and soil conditioner 4. Thus, the elution of the pollutant out of the contaminated soil can be suppressed, and it is safe because it is not eluted outside.

In addition, as shown in FIGS. 9 and 10, the concrete product 8 may be mixed with cement using pulverized industrial waste or incinerated ash 7 instead of aggregate or sand.
The concrete product 8 contains pulverized industrial waste, incinerated ash 7 and the like. In this case, the mixed powder 1 and citrus peel juice are also contained in the concrete product 8 as described above. 2. Since all or part of bamboo charcoal fragments 3 and soil conditioner 4 planted with lactic acid bacteria are mixed, the elution of pollutants from the crushed material and incinerated ash 7 is suppressed inside the concrete product 8. It is safe because it does not elute to the outside.

In the present embodiment, as an industrial waste, an old tire is reduced to 30 mm or less by the primary crusher 21, and the old tire chip crush pieces 51 of 15 mm or less are formed using the secondary crusher 22.
In the same crushing processes 21 and 22, the plastic and PVC products are also made into a crushing piece 52 of 15 mm or less.
As in the case of the shell, the ceramics and glass are made into a crushed piece 53 of 15 mm or less through the vibrating screen 13 from the hopper 11 through the crusher 12.

These crushed pieces, cement 5, sandstone 9a, crushed stone 9b, NSC (hardening agent) 9c, and water 10 are put into the batcher plant 31 to produce concrete.
The concrete thus produced can be put into a molding machine 32 such as an interlocking block machine to produce a concrete product 8 for a predetermined use.

In FIG. 10, reference numeral 7 ′ denotes waste incineration ash.
The waste to be mixed with cement is not limited to the above embodiment, and may be all or a part thereof, or may be a product obtained by crushing other waste.
In addition, it goes without saying that various design changes can be made without departing from the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Mixed powder 1A Shell powder 1B Zeolite powder 2 Squid juice of citrus fruits 3 Bamboo charcoal fragments planted with lactic acid bacteria 4 Soil improver 5 Cement 6 Concrete product 7 Industrial waste pulverized product and incinerated ash 8 Concrete product 11 Hopper 12 Crusher 13 Vibrating screen 21 Primary crusher 22 Secondary crusher 31 Batcher plant 32 Molding machine

Claims (7)

  A soil improvement method comprising mixing contaminated soil having a contaminant with a contaminated soil conditioner comprising a mixture of shell powder or granules and zeolite powder or granules.   The method for improving contaminated soil according to claim 1, wherein a powder or granule of bamboo charcoal is mixed with the contaminated soil improving agent.   3. The method for improving contaminated soil according to claim 1 or 2, wherein the contaminated soil improver is mixed with citrus fruit peel squeezed juice or citrus fruit peel dry powder.   The contaminated soil improvement method according to any one of claims 1 to 3, wherein the soil improvement agent is mixed with a soil improvement accelerator such as a nitrogen compound or an inorganic phosphorus compound.   A contaminated soil conditioner comprising the contaminated soil conditioner according to any one of claims 1 to 4.   6. A concrete product, wherein the contaminated soil conditioner of claim 5 is mixed with contaminated soil, mixed with cement and molded.   7. The concrete product according to claim 6, wherein the contaminated soil is a dried sludge soil or a soil mixed with industrial waste pulverized material or incinerated ash.

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