KR100574025B1 - Capping materials for in situ treating contaminant sediment in water, method for preparing the same and method for deploying with the same - Google Patents

Abstract

The present invention is a capping material for the treatment of water-contaminated sediments in which organic clay mixed with a reactant is coated with a polymer, and the capping material is mixed with organic reactant with a reactant, and coated with organic polymer mixed with a polymer solution, and coated organic It is prepared by mixing clay with water and drying it after molding, wherein the capping material is placed on the water contaminated sediment using at least one selected from the group consisting of barges, backhoes, conveyor belts and clamshells to form a reaction barrier layer. It is constructed accordingly.

Organoclay, Contaminated Sediment, In-situ Treatment, Capping

Description

CAPPING MATERIALS FOR IN SITU TREATING CONTAMINANT SEDIMENT IN WATER, METHOD FOR PREPARING THE SAME AND METHOD FOR DEPLOYING WITH THE SAME}

1 is a schematic diagram showing that the capping material according to the present invention forms a reaction barrier layer on the water contaminated sediment.

2 is a schematic view showing a state in which a capping protection layer is formed on the reaction blocking layer by the capping material.

Figure 3 is a SEM photograph showing a state made of powder after drying of the wyoming bentonite coated with α-cellulose which is the main component of the capping material according to the present invention.

Figure 4 is a graph showing the results of the underwater precipitation test of the capping material according to the present invention.

Figure 5 is a photograph showing the difference in turbidity in the water precipitation experiment of the capping material according to the present invention.

Figure 6 is a graph showing the results of the underwater swelling test of the capping material according to the present invention.

7 is a view showing the results of measuring the SS (suspended solid) of the organic clay as the main component of the capping material according to the present invention.

8 is a view showing the TN measurement results of the organic clay which is the main component of the capping material according to the present invention.

9 is a schematic diagram showing an apparatus for measuring the permeability coefficient of the capping material according to the present invention.

10A through 10C are photographs showing a process of forming a reaction blocking layer by a capping material according to the present invention.

11A and 11B are photographs showing a process of forming a capping protective layer after the reaction barrier layer is formed according to the present invention.

* Description of symbols on the main parts of the drawings *

1 Contaminated sediment 2 Capping material

3 water 4 reaction barrier layer

5 Strata 6 Sand

7 Gravel 8 Geotextile

10 Sample 11 Mold

12 stands pipe 13 countertop

14 reservoir 15 hole plate

16 filter 17 wire mesh

The present invention relates to a capping material for in-situ treatment of contaminated sediment in water, a method for manufacturing the same, and a method for constructing a capping material, and more particularly, a cap for in-situ treatment of contaminated sediment coated with a polymer of organic clay mixed with a reactant. It relates to a ping material, a production method thereof and a construction method of a capping material.

The Ministry of Environment is implementing the Pollution Total System as a way to strictly regulate water pollution in all water systems throughout the country, which are becoming increasingly serious. In line with this, related industries and local governments are making investments to reduce environmental pollutants to reduce water pollutants, which are increasing day by day, but they are not showing any results.

In addition to managing the inflows, the most important thing to reduce the total amount of pollution in the water system is to reduce the huge amount of pollutants currently deposited in the water system. Underwater sediments contain high concentrations of organic matter, phosphorus and nitrogen, as well as certain water hazardous substances such as heavy metals, which can adversely affect aquatic life or public health.

Ecologically, sediments are organically linked to waterbodies as important elements of the aquatic ecosystem that provide space for benthic organisms to attach or live. Contaminants such as organic wastes, nutrients, and harmful chemicals, which are included in industrial wastewater, domestic sewage, waste treatment plant leachate, and urban and rural rainfall runoff, are transported downstream and have relatively low flow rates. Settle and deposit on the ocean floor.

Accumulated organic matter generates poisonous gases during decomposition in a situation where oxygen supply is difficult, and has a fatal adverse effect on the survival of benthic organisms, and is continuously being a source of pollution through continuous elution. Toxic substances are re-dissolved into water through biochemical reactions according to changes in physicochemical environment and are concentrated along the food chain as well as aquatic organisms. The summary of the problems of contaminated sediments is as follows.

-It is a high concentration pollutant.

-Hazardous chemicals and heavy metals are concentrated.

-Causes continuous contamination due to injury of contaminated sediment.

-Without the treatment of polluted sediments, there is a limit to the management of rivers, lakes and marine pollution.

-It is fatal to the survival of benthic organisms and has a big impact on the overall ecosystem of the aquatic system.

-It is the biggest problem in the upcoming pollution total system.

-Even if the upstream water quality is improved, the pollution continues to spread downstream due to the existing sediment.

As such, the contaminated sediments are the main cause of increasing environmental pollution such as appeals and rivers, but the existing method for treating them is the only treatment of dredged contaminated sediments.

However, such dredging has a problem of re-elution that sediment moves to dredging area and re-establishes if it is carried out for a long time in the same water area, as well as potential release of harmful and toxic substances, impact of ecosystem due to temporary breeding of algae, There are problems with the reduction of organic matter that feeds benthic organisms, the generation of loud noises due to work, and the treatment of dredged materials. Therefore, because it is a large-scale project that requires a lot of budget, it is necessary to secure the resources at the planning stage, and the required resources must be short-term and shorten the project period.

Dredging method is to apply basket dredger or pump dredger in consideration of river sediment type and amount of sediment. If the dredging method is incorrectly selected, a great disruption of the aquatic ecosystem may occur during the dredging period, and the problems associated with dredging may include turbidity due to resuspension of soil and secondary pollution such as elution of new pollutants by dredging. And there is a problem of treatment of sediment soil generated after dredging. Most dredging projects have large environmental impacts caused by the project, and there are problems with the removal of dredged soil, which must be carefully considered in its implementation. Table 1 compares the advantages and disadvantages of mechanical dredging and hydraulic dredging.

Dredging method Advantages Disadvantages Mechanical · High dredging operability · Elimination of all kinds of solid matter · Elimination of contaminated deposits in water · Transport of large equipment and dredged material · Resuspend of large amount of sediment · Need to reprocess dredged material · Low dredging capacity · High dredging cost · Transport of dredged sediment Hydraulic Resuspension of sediments is relatively small.Pollutant sediments are removed from the water. Transport of large equipment and dredged materialsResolve large amounts of water entering the treatment plant together with sediment before final disposalDisruption of installed pipelines may disrupt water trafficDractive materials may remain in dredged watersReprocessing of dredged materials

Table 2 below is more detailed evaluation of the sediment dredging method.

Such various types of dredging have their own limitations and have all the problems of resuspension of sediment.

On the other hand, the present inventors have studied to solve the problems of the dredging method for treating contaminated sediments, such as appeal, river, etc. Unlike dredging, it was possible to prevent the movement of pollutants at the source, thereby completely preventing the spread and dissolution of pollutants during construction, and in the case of dredging, the present inventors have found that the secondary cost is not required due to sediment treatment. .

It is therefore an object of the present invention to provide a capping material for the treatment of contaminated sediments in water.

It is still another object of the present invention to provide a method for producing a capping material for treating a water contaminated sediment.

In addition, another object of the present invention to provide an in-situ construction method using a capping material for the treatment of water contaminated sediments.

In order to achieve the above object, the present invention provides a capping material for the in-situ treatment of contaminated sediment in water coated with a polymer of organic clay mixed with a reactant.

In order to achieve the above another object, the present invention

a) mixing organoclay with reactants;

b) coating the organic clay mixed with the polymer;

c) mixing the coated organic clay with water; And

d) provides a method of producing a capping material for in-situ treatment of contaminated sediment in water comprising the step of forming and drying the mixture.

In addition, in order to achieve the above another object, the present invention provides a capping material made of expandable clay coated with a polymer in water using one or more selected means from the group consisting of barges, back hoe, conveyor belts and clamshells In situ on contaminated sediment; And in situ capping material to form a reaction blocking layer by swelling with water.

Hereinafter, the present invention will be described in more detail.

The capping material according to the present invention is coated with a polymer material for stabilizing physicochemical properties of organic clay mixed appropriately with the reactants for treating contaminants.

As the organic clay which is the first component of the capping material according to the present invention, any organic clay having excellent expandability and watertightness may be used, but preferably Wyoming bentonite or Na-bentonite is used. Another component, the contaminant for treating pollutants, may be selected from a substance that can react with the contaminant to decompose the pollutant or remove the toxic, preferably zero valent iron, or the like. Oxidation-reducing substances or catalysts can be used. In addition, the mixing ratio of the organic clay and the reactant is preferably 10: 1 to 10: 3 based on the weight. Beyond this ratio, the use of more or less of the reactants may result in insufficient reduction of contaminants or the leakage of excess reactants.

As the polymer preparation coated on the organic clay, a polymer capable of stabilizing the physicochemical properties of the organic clay may be used, and preferably, α-cellulose or cellulose acetate, which is an environmentally friendly material, is used.

Both organic clays and polymer formulations can be selected as environmentally friendly materials produced in nature, thereby preventing secondary river pollution.

In addition, the capping material according to the invention has a pH of 6 to 9, specific gravity of 2.4 to 2.8 at 27 ℃, permeability coefficient of 10 ^-6 to 10 ^-8 m / sec is required for the in-situ treatment of contaminated sediment in water. .

The capping material according to the present invention must be dense because it must be located on top of the contaminated sediment in water, so that the dense capping material can be sprayed on the bottom and settle on the contaminated sediment to form a barrier layer, which is the barrier layer and the upper layer. Water can be completely separated. Unlike dredging, it prevents the movement of pollutants at the source, which can completely block the spread and dissolution of pollutants during construction. Therefore, the specific gravity of the capping material according to the present invention is more preferably higher specific gravity, but in consideration of the actual site conditions is preferably 2.4 to 2.8 at 27 ℃.

In addition, since the source of contaminants on the bottom surface is completely blocked by the barrier layer by the capping material, organic pollutants are decomposed through the anaerobic process, and gas may be generated in the process. Therefore, a device having a filtering function may be added during construction to remove harmful gases.

In addition, if the buffering properties of the capping material is large, that is, if the pH change is small, it is possible to prevent the desorption of the contaminants can act to reduce the contaminated sediment to an appropriate level. Therefore, in order to play such a role, the pH of the capping material should be in the range of 6-9. This saves a considerable part of the construction cost because the secondary cost of sediment treatment from dredging process does not require any capping material.

In addition, the capping material according to the present invention must have a water order so that the barrier layer by the capping material can completely separate the contaminated sediment and the water of the upper layer. Therefore, the permeability coefficient of the capping material is preferably in the range of 10 ⁻⁶ to 10 ⁻⁸ m / sec.

Method for producing a capping material according to a second object of the present invention comprises the steps of: a) mixing the organic clay with the reactant; b) coating the organic clay mixed with the polymer solution; c) mixing the coated organic clay with water; And d) molding the mixture and then drying.

The organic clay used in the mixing step a) may be an excellent clay having high expandability and watertightness, for example, Wyoming bentonite or Na-bentonite, and reacting with the pollutant to decompose the pollutant or remove the toxicity. Possible materials, such as zero valent iron, other redox materials or catalysts, may be used, and the mixing ratio thereof is preferably 10: 1 to 10: 3 by weight.

The coating step b) is iii) preparing a polymer solution by dissolving the polymer in an organic solvent; Ii) immersing and stirring the mixed organic clay in the polymer solution for mixing; Iii) evaporating the organic solvent so that the polymer is coated on the organic clay.

Dissolving the polymer in an organic solvent (iii) is to prepare the polymer in the liquid phase to coat the polymer on the organic clay. Here, the organic solvent is a high volatility that is removed in the drying step is not used as a source of contamination, for example, acetone may be used. The blending ratio between the polymer and the organic solvent may vary depending on the thickness of the target coating.

In addition, the blending ratio of the organic clay and the polymer solution mixed in the step ii) of dipping and stirring the mixed organic clay in the polymer solution may be used in an amount of 10 to 20 parts by weight of the mixed organic clay per 100 parts by weight of the polymer solution. If it is outside the polymer may not be homogeneously coated on the organic clay may cause problems in the swelling property when penetrated into water during use.

Subsequently, the step iv) of evaporating the organic solvent is performed so that the polymer is coated on the organic clay. Here, evaporation may be carried out through a drying process, specifically, room temperature drying, high temperature drying or vacuum low temperature drying, and other commonly used methods and apparatuses may be used, and preferably, dried at 10 to 25 ° C.

The organic clay coated in the mixing step c) is mixed with water. It is preferable to grind the coated organoclay before mixing with water. The grinding process is preferably milled to an average of 200 mesh (particle size) using a hammer mill or other suitable commercial grinder.

The amount of water upon mixing with water is preferably mixed in an amount of 40 to 60 parts by weight per 100 parts by weight of the polymer coated organic clay powder. If the amount of water is used less than 40 parts by weight may not be preferable because the crack may occur after drying, when used in excess of 60 parts by weight may cause a problem that the drying period is long.

The drying step d) is followed by molding the mixture and then drying. Here, the mixture can be shaped into various forms, for example granular, cubic, cylindrical, and the like, with preference being given to granular form. This is because the granular capping material may swell in all directions when penetrated into the water. In addition, when molded in a granular form, various sizes are possible, but in consideration of cracks during drying, it is preferable that the diameter is 2 to 4 cm.

The molded article may be dried at an appropriate temperature in consideration of drying time, cracking after drying, and strength development, and the drying process may use room temperature drying, high temperature drying or vacuum low temperature drying, and other commonly used methods and apparatuses. Preferably it is dried at 10-25 degreeC. Most preferably, drying at room temperature can maximize the efficiency as the capping material.

The in-situ construction method using the capping material manufactured as described above comprises the steps of: incorporating the capping material on the water contaminated sediment through at least one selected means from the group consisting of barges, backhoes, conveyor belts, and clamshells; And the in-situ capping material forms a reaction barrier layer by swelling with water.

Since the capping material according to the present invention expresses the strength required for transportation and construction, it can be transported and handled in the same way as general aggregates.

As the capping material according to the present invention is positioned on the contaminated sediment in water, the voids are closed by swelling of the capping material by water after a predetermined time, thereby forming a reaction blocking layer. 1 schematically shows that the capping material according to the present invention forms a reaction barrier layer on a water contaminated sediment. As can be seen from FIG. 1, as the capping material 2 is positioned on the contaminated sediment 1, the voids are closed between the capping materials by swelling of the capping material 2 by water 3 so that the blocking layer ( It can be seen that 4) is formed.

The amount of capping material required to cap the contaminated sediment may vary depending on environmental conditions, the amount and type of contaminated sediments, but it is preferable to form a barrier layer having a thickness of 10 cm per unit area.

In addition, a capping protection layer may be further formed on the reaction barrier layer by the capping material in order to prevent physical diffusion of river contaminants due to water flow or waves such as rivers and coasts. Depending on the physical phenomenon of the bottom surface can be composed of a combination of uncontaminated dredged clay, sand, gravel, geotextiles and the like.

When the capping protection layer is continuously formed after the capping layer is formed, the capping protection layer may exhibit a phenomenon similar to that of gravel or sand being swelled into the swollen organic clay, and thus the function of the protective layer may be reduced while the organic clay and the protective layer are mixed. Since there is, the capping protective layer is preferably installed at regular time intervals after the capping material is dropped. The capping protective layer may be constructed to protect the capping layer from shear forces that may occur in the body of water. At this time, it is good to be constructed in a sufficient amount, but considering the economic feasibility, it should be constructed to a thickness within 20cm. However, when using geotextiles can prevent the organic clay and the capping protection layer is mixed, the installation immediately after the capping material in situ may help the organic clay to maintain a lower permeability in the water body.

 In addition, for the purpose of preventing cracking and other damage caused by uneven sedimentation of the capping, a better quality capping can be completed by installing a mesh that can apply only a geotextile or a corresponding tensile force to the upper portion of the capping layer. have.

2 is a diagram schematically showing a state in which a capping protection layer is formed on a blocking layer by a capping material. As shown in Fig. 2, after the capping material according to the present invention forms the reaction barrier layer 4 on the contaminated deposit 1, sand 6; Sand 6 and gravel 7; And it can be seen that each capping protective material consisting of sand (6), gravel (7) and geosynthetic fiber (8) forms a capping protective layer on the reaction blocking layer (4).

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto. In addition, in Examples, the pH, specific gravity, swelling property, sedimentability in water, N, P adsorption property, permeability coefficient, and moldability of the capping material according to the present invention were evaluated to evaluate the efficiency as a capping material.

Example

Example 1

100 g of Wyoming bentonite as organic clay and 10 g of ferrous iron as a reactant were mixed. Subsequently, 1 mg of α-cellulose, a polymer per 100 ml of acetone, was administered and dissolved. Thereafter, 1 g of 200 mesh of wyoming bentonite mixed with ductile iron was evenly mixed at a ratio of 40 ml of the acetone solution administered with α-cellulose, dried in a drying furnace at 95 ° C., and pulverized to an average particle diameter of 200 mesh or less. After drying, it was completely dried until there was no acetone odor. After mixing in a ratio of 100 ml of water per 30 g of Wyoming bentonite mixed with fully dried ductile iron, an average diameter of 16 to 19 mm and a weight of 2.7 to 3.6 g were formed in a granular form, followed by drying for 13 days at room temperature. A ping material was prepared. The capping material according to the present invention thus prepared was used in subsequent experiments.

Example 2

Capping material was prepared in the same manner as in Example 1 except for using cellulose acetate instead of α-cellulose.

Test Example

1. SEM photograph of polymer coated organic clay

3 shows a state in which the powder made after drying of the wyoming bentonite coated with α-cellulose, which is the main component of the capping material of Example 1 according to the present invention, is shown in SEM.

2. pH measurement experiment

The pH of the capping materials of Examples 1 and 2 according to the present invention was measured to examine the applicability of the capping materials. pH measurement method was measured by soil pollution process test method published by the Ministry of Environment in 2002, measure 5g in a 50ml beaker, add 25ml of distilled water, stir with a glass rod, leave for 1 hour, adjust the pH standard solution well, and then clean the probe. Put in and read within 60 seconds. The pH measuring instrument used in the experiment was an Orion 710A pH Meter, and the instrument was calibrated using three calibration solutions. The samples of Examples 1 and 2, distilled water, acetone, Wyoming bentonite, and Wyoming bentonite and acetone mixed solution were used, and the results are shown in Table 3.

Thus, it can be seen that the capping materials of Examples 1 and 2 according to the present invention exhibit weak alkalinity. Therefore, when applied to water bodies, it is judged that there is little risk of disturbance of ecosystem.

3. Specific gravity measurement experiment

The specific gravity of the capping material obtained in Examples 1 and 2 was measured. First, Sample 1 (Example 1), Sample 2 (Example 2) and Sample 3 (Wyoming Bentonite), pycnometers, scales, thermometers and distilled water were prepared and tested by KS F 2308-91 or ASTM D854-91. Specific gravity was measured. The procedure for measuring specific gravity is as follows. 1) bottle weighing; 2) weighing the pycnometer + sample after placing the sample in the pycnometer; 3) Fill the bottle containing the sample with half distilled water and boil it over 10 minutes; 4) After cooling to 30 degrees or less, fill the rest of the pycnometer with distilled water and measure the weight and temperature of pycnometer + sample + water, respectively; 5) Fill the same pycnometer with water and measure the weight and temperature. The results are shown in Table 4.

The specific gravity of water at 22 ° C. is 0.997800 and the specific gravity of water at 27 ° C. is 0.996544. At this time, the specific gravity can be obtained using the following formula, and the results are shown in Table 5.

As can be seen from the specific gravity measurement experiment, the overall capping material according to the present invention appears to be a little less specific gravity than the unprocessed Wyoming bentonite, but when used as a capping material it can be seen that the specific gravity required by the present invention have.

4. Swelling Restoration Experiment

After the preparation of the capping material according to the present invention, an experiment was conducted to determine whether the capping material swelled from its original position.

The experiment was performed by pouring 500 ml of water into 100 ml of Wyoming bentonite in small portions and kneading the wyoming bentonite until the bubble lumps and less swelling lumps were completely removed. It dried at 99 degreeC in the drying furnace for 2 days.

The test result was that the volume of the voids measured by filling the pores between the reduced Wyoming bentonite and the vessel after drying was 6.8 ml on average. When water was added to dried Wyoming bentonite in the vessel, it was confirmed that the swelling state was restored to a volume of 60 ml.

5. Underwater Precipitation Experiment

This experiment is to determine the precipitation characteristics in the water of the capping material according to the present invention. Samples for this experiment were prepared as follows.

Sample 1 : Untreated Wyoming Bentonite

Sample 2 : A sample completely dried by administering 10 mg of cellulose acetate to 80 ml of acetone and then mixed with 100 g of bentonite.

Sample 3 : A sample treated in the same manner as Sample 2, except that α-cellulose was used instead of cellulose acetate.

Sample 4 : Comparative Sample-Sand.

100 g of the sample was mixed with 100 ml of distilled water in a 1 L cylinder and 650 ml of distilled water was further added. Precipitation patterns were observed after 30 days of complete stirring. The results are shown in FIGS. 4 to 5. Figure 4 is a graph showing the precipitation state after 30 days have passed after the precipitation of each sample, Figure 5 is a photograph showing the turbidity difference between the supernatant of the second and third samples. As can be seen from Figures 4 to 5, Wyoming bentonite is a mineral that does not precipitate well in the water is excellent in the degree of ordering, but there is a problem that turbidity is increased during complete swelling in water. However, it can be seen that the sedimentation performance was significantly improved by treating Wyoming bentonite with coating. As shown in FIG. 5, Wyoming bentonite coated using α-cellulose had better precipitation performance and reduced turbidity than Wyoming bentonite coated using cellulose acetate.

6. Underwater swellability test

This experiment is an experiment to determine whether there is a change in the swelling according to the difference in the manufacturing method of the capping material when the capping material is precipitated in water, and whether such a change of swelling property includes the problems caused by the use of the capping material.

Samples of this experiment were prepared as follows.

Sample 1 : Untreated Wyoming Bentonite

Sample 2 : Powder 25 g of bentonite bentonite was kneaded with 100 ml of acetone and dried at 99 ° C.

Sample No. 3 : 1 mg of α-cellulose per 100 ml of acetone was removed and supernatant was removed from the solution of α-cellulose precipitated in the solution. After making the powder into powder and drying it again, the sample does not smell acetone at all.

Sample 4 : A sample made by mixing the same process as Sample 3 but mixing the precipitated α-cellulose in the acetone solution to which α-cellulose was administered.

Sample No. 5 : A sample in which the dose of α-cellulose is 0.25 g, which is the same as sample No. 3.

Sample No. 6 : A sample prepared by adjusting the α-cellulose to 2.5 g after the same procedure as Sample No. 3.

25 g of each sample was added to 100 ml of distilled water in a 1 liter cylinder and distilled water was added while stirring a little to make 1 liter and then a swelling comparison test was performed. Swelling test results after 15 days have been shown in Table 8, Figure 6 is a comparison chart of each sample.

As shown in Table 8 and FIG. 6, the acetone treated sample 2 and the sample 4 treated with the α-cellulose mixed precipitated in acetone showed smaller swelling properties than the untreated Wyoming bentonite sample 1. In the case of sample 3, a trace amount of less than 1 mg of α-cellulose dissolved in acetone was administered, and in case of sample 5, 250 mg of α-cellulose was administered, but there was no significant difference in swelling. And 2500 mg of α-cellulose did not show an effect corresponding to the dose. The swelling properties of the processed samples as a whole are less swelling than unprocessed Wyoming bentonite, but when used as a capping material, they do not exhibit structural or operational defects.

7. N, P adsorption experiment

SS (suspended solid) measurement as an experiment to make the composition of organic clay that can maximize the adsorption performance of N and P by analyzing the adsorption performance of N, P in water among the properties of Wyoming bentonite, a component of capping material It was tested in parallel. TN (total phospine) and TP (total nitrogen) items were analyzed and their adsorption performance was compared. UV absorbance by water pollution test method was measured by Humas TN, TP analysis kit and HACH DR / 2010 absorbance photometer. As the measurement solution, July 1 at 1 pm, the lake water of green algae in Hannam University was used.

Samples of N and P adsorption test of organic clay were 300 ml of no addition (sample 1), ocher (sample 2), montmorillonite (sample 3), wyoming bentonite (sample 4), and activated carbon (sample 5), respectively. 150 mg (500 mg / l) was added to the water, and the mixture was precipitated at low speed for 1 hour, and then precipitated for 15 hours. Then, 50 ml of each supernatant was taken out and SS was measured. TN and TP were measured by filtered contaminated water. Twice each was measured for dissolved nitrogen and phosphorus compounds in the supernatant, and the results are shown in Table 9, and the results are shown graphically in FIGS. 7 and 8.

1.suspended solids

2. Total nitrogen (factors affecting green algae and red tide)

3. Total person (factor affecting the green algae and red tide of the lake)

As can be seen from Table 9 and FIGS. 7 and 8, the contaminated water shows a high SS of 36 mg / L, and activated carbon was found to be precipitated by adsorbing a large amount of SS. Mineral precipitation did not occur, indicating increased SS, and especially Wyoming bentonite exhibited high SS due to hydration and swelling characteristics. As a result of measuring the nitrogen compound in the dissolved state, Wyoming bentonite and activated carbon show high adsorption and removal efficiency, which indicates the effectiveness of Wyoming bentonite as a capping material, and furthermore, partial utilization of activated carbon may be considered.

8. Permeability Experiment

The purpose of this experiment is to measure the permeability coefficients of organic clay and organic clay coated with polymers, and to determine the degree of degree of ordering role in organic clay as capping material.

The experimental method is a variable permeability coefficient test and is a test according to KS F 2322 (1995). The apparatus configuration of the variable permeability coefficient test is as shown in FIG. 9, and the specifications are as follows.

Specifications of Permeability Counter

Stand pipe diameter: d1 = 1cm

-Length L: 12cm

-Cross section of standpipe a: 0.785cm ²

-Diameter of sample: d2 = 9.8cm

-Cross section A of the sample: 75.43 cm ²

Permeability Test of Organic Clay The samples used in the test are as follows.

Sample No. 1 : Wyoming Bentonite and distilled water were mixed in a volume ratio of 1:10 to complete swelling.

No. 2 sample : 1 mg of α-cellulose per 100 ml of acetone was kneaded with 100 ml of α-cellulose acetone solution per 100 ml of wyoming bentonite, dried and powdered, and then completely dried. The composition was set to 10.

Sample No. 3 : An organic clay: water ratio of 1: 5 which was treated in the same manner as Sample No. 2 was used.

The sample 10 made as described above was filled in the variable head permeability mold 11. At this time, make sure that no bubbles are formed, combine the device, fill the water, and then remove the bubble by applying water pressure from the outlet side with a pressure pump, but there is a problem in application with low water permeability, After removing as much as possible, after removing the visible bubbles below the surface of the water, the bubble was completely removed through the pitcher for 1 day and the samples inside the mold were settled stably. At this time, the measurement results are measured after the displacement amount (h ₁ and h ₂ ) and the time (t ₁ and t ₂ ) of the head in the stand pipe 12 and the value after the interval where the permeability coefficient is linear as the permeability decreases gradually. Should be used as the measurement and it should take about 1 to 3 days. After maintaining the water level in the stand pipe 12, the water permeation was stopped and the water level displacement and temperature due to evaporation were measured and corrected. The reason for this is that the evaporation amount in the stand pipe should be taken into consideration as the environmental conditions of the test site in a long time permeation experiment. As a result, the measured permeability coefficient is shown in Table 10, and the permeability coefficient value was calculated using the following equation.

As can be seen from Table 10, it can be seen that the lower the permeability of the organic clay coated with a polymer is superior to the order role.

9. Organoclay Molding Experiment I

This experiment is to investigate the molding conditions of the capping material. This is because the organic clay has a structural defect such as cracking or cracking because of high volume reduction rate when drying, and it is formed of a capping material to improve the effect of ordering function by minimizing voids between forming particles when spraying the capping material in place. Because this is required.

Samples of the organic clay molding test I were prepared as follows.

Sample No. 1 : α-cellulose: acetone was administered in a ratio of 1 mg: 100 ml, mixed evenly in a ratio of 40 ml of acetone solution in which α-cellulose was administered to 1 g of bentonite, and then dried in a 95 ° C. drying furnace and ground into powder. The organic clay was then completely dried again until there was no acetone odor. Subsequently, kneading was carried out at a rate of 100 ml of water per 30 g of completely dried organic clay, and granular shapes having an average diameter of 16 to 19 mm and a weight of 2.7 to 3.6 g were formed by hand and dried in a drying furnace at 99 ° C.

Sample 2 : The organic clay processed in the same manner as sample 1 was dried at room temperature.

Sample No. 3 : Kneading 50 g of bentonite bentonite with 60 ml of acetone solution administered with α-cellulose of sample No. 1 and kneading the state by hand to obtain a granular form having an average diameter of 16 to 19 mm and a weight of 2.7 to 3.6 g by hand. Molded and dried at room temperature.

Sample 4 : 30 ml of acetone solution in which α-cellulose was administered to 25 g of bentonite was put into a 60 ml cup-shaped paper container and dried in a drying furnace at 99 ° C.

The first sample was dried in a 99 ° C. drying furnace for one day, but drying was performed, but each granular organic clay was cracked apart.

Sample 2 was dried for 13 days at room temperature without sunlight, and the degree of drying was good and the granules were maintained. The predetermined strength was expressed and the average diameter of 9 mm was 0.64 g.

In the case of sample 3, all the molded organic clay retained its size and shape, and it could be expected to have some strength, and there was a large amount of residue on the surface. Since this sample was kneaded with acetone at the time of manufacture, it was not easy to mold because it had no stickiness of clay during molding, and it was difficult to achieve complete evaporation of acetone.

Sample 4 was bentonite dried well, was not broken, hardly felt acetone, and the volume after drying was 17 ml. However, the application of the capping material on the actual site could not be expected to develop the minimum strength that can be transported.

Through the above experimental results, it can be seen that the mixing of the organic clay primarily with acetone, and then drying the organic clay molded by kneading with water at room temperature can increase its effectiveness as a capping material.

10. Organoclay Molding Experiment Ⅱ

This experiment is to find the difference of drying time according to the size of capping material and the size of granular moldable.

Wyoming bentonite: acetone was uniformly kneaded at a volume ratio of 1: 1 by administering 1 mg of α-cellulose per 100 ml of acetone. After drying completely in a drying furnace at 98 ℃, the mass was made into a powder and dried again so that there was no acetone odor. The powder was processed evenly by mixing the volume ratio of processed Wyoming bentonite: distilled water in a ratio of 1: 1.2, and the dough was measured to have a granular diameter of 2, 3, 4, or 5 cm by measuring with a vernier caliper. Molding was done by hand within an error limit of less than ± 20% and then the weight of each finished granule was measured. Dry in the shade of a room well ventilated at room temperature, but not heated and blown to determine whether it is out of the room temperature to adjust the temperature of the room and dried.

As for the drying period of the organic clay granular molding, as shown in Table 11, the drying was performed for 18 days for the 2-3cm diameter molding and 21 days for the 4cm molding, and the granular molding having the diameter of 5cm was split in half. Granular molding of 5 cm size is a useful size if it utilizes a variety of sizes, but quality control of molding drying is difficult.

The measured data were not sampled when the granularity (minimum diameter / maximum diameter)> 30%. The weight before and after drying of each granular organic clay and the diameter change after drying are shown in Tables 12 to 14 below, and the volume reduction rate is shown in Table 15.

As can be seen through Tables 11 to 15, as the capping material according to the present invention, the organic clay may be usefully used as a granular form having a diameter of 2 to 4 cm before drying.

11. Organoclay Molding Test Ⅲ

This experiment is to increase the specific gravity of granules in order to make sedimentation efficient when spraying the capping material in water when using organic clay as capping material. Organic clay to reduce further: Test for reconstitution of water composition ratio. In addition, when the capping material is sprayed on the water body in the field, the drop speed according to the particle size is recognized and the particle size distribution of the capping material is measured in parallel with the drop time in order to maintain the composition and homogeneous quality. .

Samples used in this experiment were evenly kneaded with 1 kg: 1 L of a Wyoming bentonite: α-cellulose acetone solution by administering 1 mg of α-cellulose per 100 ml of acetone. After completely drying in a drying furnace of 99 ℃, the mass was made into a powder and dried again so that there was no acetone odor. The processed wyoming bentonite: distilled water of the powder was mixed to 1kg: 1l to make the dough evenly. While measuring the dough with vernier calipers, the granular diameter was molded by hand within an error limit of less than ± 20% of the reference diameter, and the granular diameter was 2 and 3 cm and the core was 2 and 3 cm. It was prepared respectively. In this case, the cores of the granular molding passed through a 9.5 mm sieve and the gravel remaining in the 5.66 mm sieve was used as a 3 cm diameter granular core, and the gravel passing through the 5.66 mm sieve and remaining in the 4.75 mm sieve was used as the 2 cm granular core. . The weight of each completed molding was measured, and dried in the shade of a room with ventilation at room temperature, while checking the thermometer without heating and blowing to determine whether the room temperature was out of room temperature. 20% specimens were randomly selected and the maximum and minimum diameters of one granule were measured and the average value was applied to the corresponding granular diameter. The figurine was not sampled. The drying period is shown in Table 16 below, and the drying results of the granular molding are shown in Table 17 below.

As shown in Table 16, there was no difference in the actual drying period, since the size of the core occupied in the total granular volume, and as shown in the results of Table 17, a large amount was used. Cracks occurred, and the cracks generated were generally 2 or 3 small cracks within 5mm, and there was no functional problem as a capping material. Can be. The weight reduction rate is all 46% or more and contains a small amount of moisture therein, and when the core is used, the weight reduction rate is lower than that of the granules without the core due to the weight of the core. The decrease in volume shows more volume reduction in the 2 cm diameter granules as shown in Table 17. Although not shown in the result data, the granules were dry-tested using a core of aggregate equal to the core size of the granule having a diameter of 4 cm, but a large amount of cracks occurred.

Therefore, the usefulness of core insertion in organic clay for increasing the specific gravity of the capping material according to the present invention is reserved.

The sedimentation rate of the molded organic clay granules was determined by dropping the dried organic clay granules with water in a 1L mass cylinder and measuring the time and the dropping distance. The values are shown in Table 18.

In each size, there was no difference in the falling speed between the granules used and the unused granules. In fact, the biggest factor in the dropping velocity of granularity is the diameter.

12. Blocking layer formation test of capping material

25 capping materials in the form of granules of 16 to 19 mm in diameter and weight of 2.7 to 3.6 g, prepared according to Example 1, were placed in a 1 L beaker, and then water was added to fill the 1 L beaker. Then, before the water addition, after 6 hours and 24 hours after the addition of water, the change in the capping material was photographed and shown in Figure 10a, 10b and 10c, respectively. As shown in FIGS. 10A to 10C, the capping material according to the present invention absorbs water in the water body to swell and forms a thick blocking layer while swelling and forming voids between the granular capping materials at the same time. Subsequently, a capping protective material made of sand, gravel and geotextiles was infiltrated thereon, and photographs immediately after infiltration and two days after infiltration were shown in FIGS. 11A and 11B, respectively. As shown in Figure 11a and 11b, it can be seen that the capping protective material consisting of sand, gravel and geotextiles precipitated on the capping layer to form a capping protective layer. Also, as shown in FIG. 11B, no trace of the capping protection material penetrated into the blocking layer made of the capping material was observed.

Capping material according to the present invention is excellent in environmental friendliness, swelling, immersion, water repellency and adsorption of pollutants, the construction method of capping the contaminated sediments in water using such a capping material is quite simple and additional cost due to the use of expensive equipment The construction constraints are less than dredging because the noise generated during construction is small. In addition, there is no difference in construction by the area of the polluted sedimentation area, thus exhibiting excellent workability in various sites. This is directly related to construction efficiency and performance, which is a very important advantage in the quality control of capping.

 Table 19 compares the advantages and disadvantages between the original construction method using the capping material according to the present invention as described above and the existing sediment dredging method.                     

Claims (14)

Capping material for in-situ treatment of water-contaminated sediments coated with cellulose-based polymers of organic clay mixed with at least one selected reactant from the group consisting of zero iron and other oxidizing and reducing substances and catalysts. The capping material of claim 1, wherein the organic clay comprises Wyoming bentonite or Na-bentonite. delete The capping material of claim 1, wherein the mixing ratio of the organic clay and the reactant is 10: 1 to 10: 3 by weight. The capping material of claim 1, wherein the polymer comprises α-cellulose or cellulose acetate. The capping material of claim 1, wherein the capping material has a pH of 6 to 9, specific gravity of 2.4 to 2.8, and a permeability coefficient of 10 ^-6 to 10 ^-8 cm / sec. . a) mixing the organic clay with at least one reactant selected from the group consisting of ferrous iron, other redox materials and catalysts; b) coating the cellulose-based polymer on the mixed organic clay; c) mixing water with the coated organic clay; And d) a method of producing a capping material for in situ treatment of contaminated sediment in water, comprising the step of forming a mixture and then drying it. The method of claim 7, wherein the mixing ratio of the organic clay and the reactant in the mixing step a) is 10: 1 to 10: 3 based on weight. 8. The method of claim 7, wherein the coating step b) comprises: i) dissolving the polymer in an organic solvent to prepare a polymer solution; Ii) immersing and stirring the mixed organic clay in the polymer solution for mixing; Iii) a method of producing a capping material for in situ treatment of water-contaminated sediments comprising evaporating an organic solvent such that the polymer is coated on organic clay. 8. The method according to claim 7, wherein the mixing step c) adds and mixes 40 to 60 parts by weight of water per 100 parts by weight of the coated organic clay. 8. The method of claim 7, wherein the drying step d) is to form the mixture into a granular form and then to dry it at 10 to 25 ° C. Repositioning the capping material made of the organic clay coated with the cellulose-based polymer onto the water contaminated sediment using at least one selected from the group consisting of a helicopter, a barge, a backhoe, a conveyor belt, and a clamshell; And in situ capping material to form a reaction barrier layer by swelling with water. The method of claim 12, further comprising forming a capping protection layer by placing a capping protection material on the blocking layer to protect the blocking layer after the reaction blocking layer forming step. The method of claim 13, wherein the capping protection material is selected from the group consisting of gravel, sand and geotextiles.

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