JP4182011B2 - Method for modifying and solidifying mud water and using modified solidified soil - Google Patents

Description

  The present invention relates to a modified solidification method for wastewater and a method for using the modified solidified soil. More specifically, the present invention relates to a modified solidification method for reforming and granulating high water content wastewater generated from civil engineering work sites such as propulsion work. The present invention relates to a method and a method for reusing a modified granulated soil.

When excavation work is carried out in civil engineering work, mountain sand has been used as a backfill material, but in recent years it has become difficult to obtain as a backfill material due to restrictions on the collection of mountain sand from the viewpoint of nature conservation. .
In addition, it is difficult to store the remaining soil from excavation and transport it to the site as needed to use it as a backfill material.

  Conventionally, waste water with a high water content is usually dehydrated by a dehydrator such as a filter press. However, dehydrated cake is hard and non-breathable, so it is unsuitable for use as a plant growth base material. Furthermore, when water was included, it became soft clay and could not be used as backfill ground, and the dehydrated cake could only be treated as industrial waste. In addition, the muddy water contains bentonite, CMC, polycarboxylic acid and the like, and there is a problem that a large amount of chemical is required for dehydration treatment.

Therefore, for example, as a method of treating so as not to cause harm to the environment, a method of dehydrating after adding a water-soluble metal salt to boring wastewater has been proposed (see Patent Document 1).
Further, in order to prevent the treated soil from increasing, a method has been proposed in which a pretreatment is performed in which relatively dry mud or sand is mixed with high water content mud, mud or sludge (see Patent Document 2).
However, these methods have problems such as including an operation of dewatering muddy water, or the amount of treated soil inevitably increases due to the addition of dry soil.

On the other hand, it is known to add and coagulate organic waste flocculant to waste water, such as construction sludge with high water content, sludge, and treated materials in which incinerated ash, coal ash, etc. are mixed in these dewatered cakes A method for producing a granular material usable as embankment, earth covering material, drain material, etc. by adding a polymer or the like as an additive to a kneading mixer with a specific structure is disclosed (Patent Document 3). reference). Further, the product form of the organic polymer flocculant used is known as a water-in-oil emulsion polymerized product or a salt-water dispersion polymerized product, etc., and a method for producing a water-in-oil emulsion (for example, Patent Document 4, Patent Document 5). And Patent Document 6) and a method for producing a dispersion in an aqueous salt solution (see, for example, Patent Document 7 and Patent Document 8) are also known.
Japanese Patent Laid-Open No. 11-188392 JP 2001-121159 A Japanese Patent Publication No.34-10644 JP 2003-1297 A Japanese Patent Publication No.52-39417 Japanese Patent Publication No. 55-45783 Japanese Examined Patent Publication No. 46-14907 JP-A-62-20511

The first object of the present invention is to solve the conventional problems and to dry the mud water having a high water content ratio generated from a civil engineering work site such as a propulsion work which has conventionally only been treated as industrial waste without being dehydrated or dried. It is to provide a reforming and solidifying method for reforming and granulating by a simple operation that can be used in any structure mixer without adding soil and adding treated soil,
The second object of the present invention is to provide a method for reusing the granulated soil thus modified and solidified.

  As a result of diligent research to solve the above-mentioned problems, the inventors of the present invention required an organic polymer flocculant, fly ash, cement, and a chelating agent for preventing elution of heavy metals in waste water with a high water content. When added as a component, mixed and stirred, the water appears to have disappeared and appears granulated, and leaving it granulated increases the strength of the granulated soil. It was found that it could be used, and the present invention was completed.

That is, the method for reforming and solidifying wastewater of claim 1 of the present invention for solving the above-described problem is (a) a dispersion liquid (meta) in a state of being dispersed as it is in a stock solution in wastewater generated from a civil engineering work site. An acrylic water-soluble polymer flocculant, (b) fly ash, (c) cement, and (d) a chelating agent for preventing elution of heavy metals are added as essential components and granulated.

  The method for reforming and solidifying wastewater of claim 2 of the present invention is the method for reforming and solidifying wastewater of claim 1, wherein the wastewater is a wastewater having a high water content ratio with a specific gravity of 1.2 or less. It is characterized by.

Reforming solidification method of the exhaust mud according to claim 3 of the present invention, in the reforming solidification method of the exhaust mud according to claim 1 or claim 2, wherein said fly ash is added 500~1500Kg to discharge muddy water 1 m ³ It is characterized by that.

Reforming solidification method of the exhaust mud according to claim 4 of the present invention, in the reforming solidification method discharge muddy water according to any one of claims 1 to 3, the cement, to discharge muddy water 1 m ^3, 50 It is characterized by adding ~ 500 kg.

According to claim 5 of the present invention, (a) a dispersed liquid (meth) acrylic water-soluble polymer flocculant in a state of being dispersed as a stock solution in wastewater generated from a civil engineering site , (b) fly ash, (c A modified solidified soil characterized by reusing a granulated soil, which has been modified and solidified by adding a chelating agent as an essential component )), cement, and (d) to prevent heavy metal elution How to use.

The method for reforming and solidifying wastewater according to claim 1 of the present invention includes (a) a dispersed liquid (meth) acrylic water-soluble polymer flocculant in a state of being dispersed as it is in the wastewater generated from the civil engineering work site , (B) fly ash, (c) cement, (d) a chelating agent for preventing elution of heavy metals is added as an essential component and granulated,
(A) Dispersed liquid (meth) acrylic water-soluble polymer flocculant in the state of being undiluted in wastewater generated from civil engineering work site, (b) fly ash, (c) cement, (d) heavy metal When a chelating agent to prevent elution is added as an essential component and mixed and stirred, fine particles such as silt and clay in the mud waste water aggregate and water is taken into the voids of the floc and apparently water disappears. It has a remarkable effect that it can be granulated into a dry state. Also, by using a dispersed liquid (meth) acrylic water-soluble polymer flocculant, the high-molecular weight (meth) acrylic water-soluble polymer is dispersed finely in the liquid. It can be used in a state of being dispersed as it is, and can be easily kneaded with any structure mixer. As a result, it can be used from civil engineering work sites such as propulsion work that has conventionally only been treated as industrial waste. The generated high moisture content mud can be granulated by modifying and solidifying by simple operation without dehydrating or adding dry soil to increase the treated soil. By leaving the modified and solidified granulated soil, the strength of the granulated soil is increased by the hydration reaction of cement and fly ash, and there is soil resistance due to compaction, so it can be reused as backfilling soil or soil for creation. A marked effect say.
In addition, by adding a chelating agent for preventing heavy metal elution as an essential component, even if heavy metal is contained in the wastewater, it can be fixed by this chelating agent to prevent elution of heavy metal, and it can be modified and solidified. After granulating, there is a significant effect that heavy metals can be eluted from the granulated product and secondary contamination can be prevented.

  The method for reforming and solidifying wastewater of claim 2 of the present invention is the method for reforming and solidifying wastewater of claim 1, wherein the wastewater is a wastewater having a high water content ratio with a specific gravity of 1.2 or less. Even if it is the drainage water of high water content ratio whose specific gravity is 1.2 or less, there is a further remarkable effect that it can be granulated well.

The reforming and solidifying method of waste water of claim 3 of the present invention is the method of reforming and solidifying waste water of claim 1 or 2, wherein 500 to 1500 kg of fly ash is added to 1 m ^{3 of} waste water. Within this range of addition, there is a further remarkable effect that it can be well-modified and solidified and granulated by a simple operation.

Reforming solidification method of the exhaust mud according to claim 4 of the present invention, in the reforming solidification method discharge muddy water according to any one of claims 1 to 3, the cement, to discharge muddy water 1 m ^3, 50 It is characterized by the addition of ˜500 kg, and within this addition range, there is a further remarkable effect that it can be well-modified and solidified and granulated by a simple operation.

According to claim 5 of the present invention, (a) a dispersed liquid (meth) acrylic water-soluble polymer flocculant in a state of being dispersed as a stock solution in wastewater generated from a civil engineering site , (b) fly ash, (c A modified solidified soil characterized by reusing a granulated soil, which has been modified and solidified by adding a chelating agent as an essential component )), cement, and (d) to prevent heavy metal elution Is the usage of
(A) Dispersed liquid (meth) acrylic water-soluble polymer flocculant in the state of being undiluted in wastewater generated from civil engineering work site, (b) fly ash, (c) cement, (d) heavy metal When a chelating agent to prevent elution is added as an essential component and mixed and stirred, fine particles such as silt and clay in the mud waste water aggregate and water is taken into the voids of the floc and apparently water disappears. It has a remarkable effect that it can be easily granulated.
Also, by using a dispersed liquid (meth) acrylic water-soluble polymer flocculant, the high-molecular weight (meth) acrylic water-soluble polymer is dispersed finely in the liquid. It can be used in a state of being dispersed as it is, and can be easily kneaded with any structure mixer. As a result, it can be used from civil engineering work sites such as propulsion work that has conventionally only been treated as industrial waste. Remarkable that the generated high water content mud can be easily granulated without dehydration or by adding and adding dry soil and increasing the treated soil, by simple operation. Has an effect.
In addition, by leaving the granulated soil modified and solidified in this way, the strength of the granulated soil is increased by the hydration reaction of cement and fly ash, and there is also soil resistance due to compaction, so that the soil for backfilling and soil for creation is increased. In addition, by adding a chelating agent to prevent heavy metal elution as an essential component, even if heavy metal is contained in the sludge water, it can be fixed by this chelating agent and prevent heavy metal elution. After the reforming, solidification, and granulation, there is a remarkable effect that the secondary contamination can be prevented without fear of elution of heavy metals from the granulated product.

  In the present invention, the organic polymer flocculant to be added to the waste water is not particularly limited, but a dispersed liquid acrylic polymer flocculant can be particularly preferably used. That is, the dispersed liquid acrylic polymer flocculant is a water-in-oil emulsion polymer or a salt-water dispersion polymer, and a high molecular weight acrylic water-soluble polymer is finely dispersed in the liquid. Therefore, it can be used in a state of being undiluted and dispersed without being diluted, and can be easily kneaded with a mixer having any structure. The method for producing a water-in-oil emulsion dispersion is described in Patent Documents 4 to 6, and the method for producing a dispersion in salt aqueous solution is described in Patent Documents 7 to 8.

  The (meth) acrylic polymer flocculant preferably used in the present invention is a (meth) acrylic water-soluble polymer. The chemical composition is a (co) polymer of ionic water-soluble monomers or a copolymer of ionic water-soluble monomers and nonionic water-soluble monomers.

  In the present invention, a copolymer of 3 to 100 mol% ionic water-soluble monomer and 0 to 97 mol% nonionic water-soluble can be preferably used.

Examples of the ionic water-soluble monomer include acrylic cationic monomers such as dialkylaminoalkyl (meth) acrylate salts and / or quaternized products thereof, dialkylaminoalkyl (meth) arrylamide salts and / or quaternized products thereof, and (meth ) Acrylic acid or a salt thereof or an acrylic anionic monomer such as 2-acrylamidoalkyl sulfonate.
These ionic water-soluble monomers can be used in combination of two or more, and can be copolymerized with (meth) acrylamide.

  Nonionic water-soluble monomers include (meth) acrylamide, diacetone acrylamide, N-vinylformamide, N-vinylacetamide, acryloylmorpholine, N-vinylpyrrolidone, and most preferably acrylamide. In addition, a hydrophobic monomer such as acrylonitrile may be copolymerized as long as it is in an amount that does not adversely affect the aggregation of 20% by mass or less.

  Particularly preferable among the acrylic polymer flocculants is a copolymer of 3 to 50 mol% ionic water-soluble monomer and 50 to 97 mol% nonionic water-soluble monomer, and more preferable. Acrylic such as (meth) acrylic acid or a salt thereof or 2-acrylamidoalkyl sulfonate, which is a copolymer of 3 to 50 mol% of an anionic water-soluble monomer and 50 to 97 mol% of a nonionic water-soluble monomer It is a copolymer of an anionic monomer and a nonionic water-soluble monomer.

The molecular weight of these dispersed liquid polymer flocculants is preferably 1 million or more and 20 million or less, and more preferably 3 million or more and 15 million or less from the viewpoint of the aggregation effect.
These dispersed liquid polymer flocculants can be added as an aqueous solution, but are more preferably added as a dispersion. The water-soluble polymer particles in the dispersion preferably have a particle size of 100 μm or less.
When the particle size is within this range, the dispersion can be used in a state of being dispersed as it is without being diluted with water, and can be easily added to and mixed with waste water having a high water content. Can be preferably used.

The amount of the dispersed liquid organic polymer flocculant used in the present invention is not particularly limited. However, from the viewpoints of agglomeration and granulation, it is preferable to add 0.5 to 5 kg of mixed water per 1 m ³ of high water content as a normal polymer content, and particularly preferably 1.0 to 3.0 kg. Add and mix.

The addition method is not particularly limited. However, usually a forced-stir mixer is used to mix and stir wastewater with a high water content with a chelating agent, then mix and stir the dispersed liquid polymer flocculant, and add fly ash and cement to mix and stir. It is preferable to stir.
In the present invention, since a dispersed liquid polymer flocculant is used for granulation, the stirring mixer is not particularly limited, and any type can be used, and a mixer such as a continuous mixer or a forced stirring mixer should be used. Is possible. A forced stirring mixer can be preferably used.

  With stirring, fine particles such as silt and clay in the mud waste water aggregate, and water is taken into the voids of the flocs, and apparently becomes watery and granulated as if there was no water.

By leaving this untreated, the strength of the granulated soil is increased by the hydration reaction between cement and fly ash, and there is also soil resistance due to compaction. Can be reused as
As described above, the method for reforming and solidifying wastewater of the present invention is very practical because it is easy to operate and can suppress the increase of treated soil as much as possible.

In this invention, it is preferable that the fly ash added to waste water is 500-1500Kg with respect to 1m < ³ > of mud water, and it is more preferable that it is 1000-1500Kg. Within this range of addition, it can be reformed and solidified and granulated by a simple operation. If it is less than 500 Kg, there is a possibility that it is fluid and does not solidify, and if it is more than 1500 Kg, it is not necessary to add an organic polymer flocculant, but the amount added is too large and the amount of mud water is increased. There is a risk that it will become wasteful and uneconomical.

On the other hand, in the present invention, the cement to be added to discharge mud, to discharge muddy water 1 m ^3, it is preferably 50～500Kg, and more preferably 100 to 300. Within this range of addition, it can be granulated by good modification and solidification by a simple operation. If it is less than 50 kg, it may not be reformed and solidified, and if it exceeds 500 kg, it may be uneconomical.

  The following can be used for the chelating agent used in the present invention. That is, dithiocarbamic acid type chelating agent, thiourea type chelating agent, polyamine type chelating agent, imino diacetic acid type chelating agent, pyrrolidine type chelating agent, imine type chelating agent, hydroxy acid, etc. Ethylenediaminetetraacetic acid, trans-1,2-cyclohexanediaminetetraacetic acid, glycol etherdiaminetetraacetic acid, diethylenetriaminepentaacetic acid, nitrilotriacetic acid, and the like. In addition, there are hydroxy acid such as citric acid, malic acid, tartaric acid, glycolic acid, salicylic acid, and others, oxalic acid, maleic acid, phthalic acid, citric acid, sulfosalicylic acid, β-mercaptopropionic acid, thioglycolic acid, dimercaptopropionic acid Etc.

These chelating agents can be added in any order with other additives, but the above chelating agent is added to and mixed with the sludge water, and then the dispersed liquid polymer flocculant is mixed, and further fly ash and Cement is preferably added. The amount of the chelating agent added to the solidified granulated material kneaded with waste water, fly ash, cement, dispersed liquid polymer flocculant, etc. is 0.5-10 kg / m ³ (about 0.04-0.8% by mass). However, it is preferably 1 to 6 kg / m ³ (about 0.08 to 0.48 mass%).

  In the present invention, the inorganic flocculant, sand, and the like within the range that does not depart from the gist of the present invention other than the dispersed liquid organic polymer flocculant, fly ash, cement, and chelating agent in the waste water Etc. can be added.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to these examples.
Hereinafter,% indicates mass%.

(Synthesis Example 1)
A reaction vessel equipped with a stirrer and a temperature controller was charged with 126.0 g of isoparaffin having a boiling point of 190 ° C. to 230 ° C. and 12.0 g of sorbitan monooleate. After adding 210.0 g of deionized water and 176.4 g of 80% aqueous acrylic acid (AAC) and 278.4 g of 50% aqueous acrylamide (AAM), 224.0 g of 35% aqueous solution of sodium hydroxide (equivalent to acrylic acid) ) Was added while cooling so that the liquid temperature did not exceed 30 ° C. The molar ratio of acrylamide to acrylic acid after monomer incorporation is 50:50, and the concentration is 40%. Thereafter, the mixture was emulsified with stirring at 1000 rpm with a homogenizer for 60 minutes. To the obtained emulsion, 0.84 g of isopropyl alcohol (0.03% monomer) was added, and after nitrogen substitution, 2,2′-azobis [2- (5-methyl-2-imidazoline-2) was used as an initiator. -Yl) propane] 2.8 g of a 10% aqueous solution of dihydrochloride was added, and the polymerization reaction was started while controlling the temperature at 33 ± 1 ° C. After 5 hours, 0.56 g of the initiator was added, and another 5 The reaction was continued for a time to complete the polymerization. After the polymerization, 6.0 g of polyoxyethylene tridecyl ether (1.2% with respect to the liquid) was added and mixed as a phase inversion agent to the resulting water-in-oil emulsion (Sample-1). Moreover, when the weight average molecular weight was measured with the molecular weight measuring device (DLS-7000 by Otsuka Electronics Co., Ltd.) by a static light scattering method, the molecular weight was 11 million.

(Synthesis Example 2)
In a four-necked 500 ml separable flask equipped with a stirrer, reflux condenser, thermometer and nitrogen inlet tube, 107.7 g of deionized water, 44.7 g of ammonium sulfate, 32.7 g of 60% aqueous acrylic acid (AAC), 50% After adding 90.3 g of aqueous acrylamide (AAM), 16 mol% of acrylic acid was neutralized with 5.8 g of 30% aqueous solution of sodium hydroxide. Into this, 15.6 g of sodium 2-acrylamido-2-methylpropanesulfonate polymer (25% aqueous solution, 8,300 mPa · s) (6.0% monomer) was added as a polymer dispersant. Thereafter, nitrogen is introduced from the nitrogen introduction tube while stirring to remove dissolved oxygen. During this time, the internal temperature is adjusted to 30 ° C. using a constant temperature water bath. Thirty minutes after the introduction of nitrogen, 0.1% aqueous solution of ammonium peroxodisulfate and 0.1% aqueous solution of ammonium hydrogensulfite was added in this order in an amount of 0.6 g (counter monomer, 9.4 ppm) to initiate polymerization. After 3 hours from the start of polymerization, the same amount of each initiator was added, and after 6 hours, 1.8 g was added and the reaction was completed in 15 hours. The molar ratio of acrylic acid to acrylamide in the polymer was 30:70, the concentration was 20%, and the viscosity was 240 mPa · s (Sample-2). As a result of microscopic observation, the particles were found to be 5 to 35 μm. Moreover, when the weight average molecular weight was measured, the molecular weight was 9 million.

[Example 1]
1000 ml of waste mud water (specific gravity 1.2) is put into a forced stirring mixer, 500 g of fly ash (combustible waste incineration ash), 7.5 g of ethylenediaminetetraacetic acid as chelating agent (1.5% by mass of fly ash, 0% of total amount) .39%) After addition and mixing, 1 g of the (meth) acrylic polymer flocculant of Sample-1 produced in Synthesis Example 1 was added and mixed, 200 g of cement was added and mixed, and the state after treatment was observed.
Moreover, the sample soil was created according to the soil compaction test method by tamping, and the penetration test was conducted as a portable cone penetration test (test method: according to JIS-A-1210).

A cone having a tip angle of 30 degrees (cone bottom area 6.45 cm ² and 3.23 cm ² ) is press-fitted by human force at a speed of 1 cm / s, and the penetration resistance value up to 30 cm is measured every 10 cm to obtain an average. It was. This penetration resistance value was divided by the bottom area to calculate the cone index.
The results are shown in Table 1. In Table 1, the waste water is in milliliters, each additive is in grams, and the corn index is in KN / m ² .

[Examples 2 to 6]
The amount of each component shown in Table 1 was added to and mixed with wastewater by the same operation as in Example 1, the state after treatment was observed, and a portable cone penetration test was conducted in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Examples 1-4)
The amount of components shown in Table 1 was added to and mixed with waste mud water by the same operation as in Example 1, the state after treatment was observed, and the test was performed. The results are shown in Table 1.

From Table 1, in Examples 1-6, it turns out that the sludge drainage was able to be granulated and modified satisfactorily. When the strength was measured in order to use the granulated soil modified with granulation as a backfill material, the cone index was 1,000 to 2,000 KN / m ² . While the formulation is also possible cone index 3,000KN / m ² or more strength, the strength of the normal backfill material if cone index 1,000~2,000KN / m ² is sufficient.
On the other hand, in the formulation of Comparative Example 1, wastewater and (meth) acrylic polymer flocculant were added to and mixed with the forced stirring mixer, and the mixture was stirred and stirred.
In the blending of Comparative Example 2, waste water and (meth) acrylic polymer flocculant were added to and mixed with the forced stirring mixer, and fly ash was added and stirred.
In the formulation of Comparative Example 3, when the sludge water was added to and mixed with a forced stirring mixer, and fly ash and cement were added and stirred, granulation was possible, but the strength was very weak.
In the formulation of Comparative Example 4, waste water was added to and mixed with the forced stirring mixer, and fly ash was added and stirred to find a soft lump.

(Comparative Example 5)
Using the same fly ash as in Example 1, the elution test for heavy metal ions after granulation was performed. First, the elution amount of each heavy metal after solidification and granulation without adding a chelating agent was tested.
That is, 1000 ml of eluted mud water (specific gravity 1.2) is charged into a forced stirring mixer, 500 g of fly ash (combustible waste incineration ash) and 1 g of (meth) acrylic polymer condensing agent of Sample-1 are added and mixed. 200 g was added, mixed and granulated. Then, it was left to stand for 24 hours, and an elution test for the granulated material was conducted according to Notification No. 13 of the Environmental Agency in 1973. The results are shown in Table 2.

  From Table 2, it can be seen that in the granulated product of Comparative Example 5, lead exceeds the landfill standard value, but cadmium, total mercury, hexavalent chromium, arsenic, and selenium all fall below the landfill standard value.

[Example 7]
Dissolved waste mud water (specific gravity 1.2) 1000ml was put into a forced stirring mixer, the same fly ash (combustible waste incineration ash) 500g as in Example 1, ethylenediaminetetraacetic acid as a chelating agent against fly ash 1%, 1.5% After adding and mixing 3% respectively, 1 g of the (meth) acrylic polymer flocculant of Sample-1 produced in Synthesis Example 1 was added and mixed, and 200 g of cement was added and mixed for granulation. Then, it was left to stand for 24 hours, and an elution test for the granulated material was conducted according to Notification No. 13 of the Environmental Agency in 1973. In the granulated product of Comparative Example 5, only lead exceeded the landfill standard value, and cadmium, total mercury, hexavalent chromium, arsenic, and selenium were all below the landfill standard value, so only lead was measured. The results are shown in Table 3.

  From Table 3, it can be seen that when the chelating agent is added and mixed in excess of 1% to fly ash, the elution amount of lead is lower than the landfill standard value.

The method for reforming and solidifying wastewater of the present invention comprises (a) a dispersed liquid (meth) acrylic water-soluble polymer flocculant in a state of being dispersed in the wastewater generated from a civil engineering work site, and (b) a fly. Ash, (c) cement, (d) a chelating agent for preventing elution of heavy metals is added as an essential component and granulated. When the ingredients are added and mixed and stirred, the fine particles such as silt and clay in the sludge water aggregate and water is taken into the flock voids. Also, by using a dispersed liquid (meth) acrylic water-soluble polymer flocculant, the high-molecular weight (meth) acrylic water-soluble polymer is dispersed finely in the liquid. Without change It can be used in a dispersed state and can be easily kneaded with any type of mixer. As a result, high water content generated from civil engineering work sites such as propulsion work that has conventionally only been treated as industrial waste It is possible to granulate by reforming and solidifying by a simple operation without dehydrating or adding dry soil without increasing the amount of treated soil. By leaving the granulated soil, the strength of the granulated soil is increased by the hydration reaction of cement and fly ash, and there is a remarkable effect that it can be reused as backfilling soil or soil for creation because it has soil resistance due to compaction. In addition, by adding a chelating agent as an essential component to prevent elution of heavy metals, even if heavy metals are contained in the wastewater, they are immobilized by this chelating agent It is possible to prevent, after reforming and solidifying and granulating, there is no fear that heavy metals will be eluted from the granulated product, and it is possible to prevent secondary contamination. High utility value.

Claims (5)

(A) Dispersed liquid (meth) acrylic water-soluble polymer flocculant in the state of being undiluted in wastewater generated from civil engineering work sites , (b) fly ash, (c) cement, (d) elution of heavy metals A method for reforming and solidifying mud water characterized by adding a chelating agent for preventing water as an essential component and granulating.   The method for reforming and solidifying wastewater according to claim 1, wherein the wastewater is wastewater having a high water content ratio with a specific gravity of 1.2 or less. The fly ash, reforming solidification method discharge muddy water according to claim 1 or claim 2 to discharge muddy water 1 m ^3, characterized in that the addition 500～1500Kg. The method for reforming and solidifying wastewater according to any one of claims 1 to ³ , wherein 50 to 500 kg of the cement is added to 1 m3 of wastewater. Civil construction site to discharge muddy water generated from the (a) dispersion liquid while the dispersion state of the stock solution (meth) acrylic-based water-soluble polymer coagulant, (b) fly ash, (c) cement, (d) heavy metal elution A method for using a modified solidified soil, characterized by reusing a granulated soil which has been modified and solidified by adding a chelating agent as an essential component to prevent re-use as a backfill material or a soil for creation.