KR101200278B1 - Sewage sludge solidified agent and menufacturing method of artificial soil usign the same - Google Patents

Abstract

The present invention relates to a method for producing sewage sludge solidified material and artificial soil, and more particularly, by reducing the water content of sewage sludge by absorbing and exothermic action of CaO contained in a large amount of incineration residues, and deodorizing and sterilizing microorganisms. Sludge solidified fire and an artificial soil manufacturing method using the same.
Sewage sludge solidified material according to the present invention is based on 100 parts by weight of incineration residue having a calcium oxide (CaO) content of 20% to 70%, 5 to 50 weight of fly ash having a calcium oxide content of 0.1 to 5% Contains wealth.

Description

Sewage sludge solidified fire and artificial soil manufacturing method using the same {SEWAGE SLUDGE SOLIDIFIED AGENT AND MENUFACTURING METHOD OF ARTIFICIAL SOIL USIGN THE SAME}

The present invention relates to a method for producing sewage sludge solidified material and artificial soil, and more particularly, by reducing the water content of sewage sludge by absorbing and exothermic action of CaO contained in a large amount of incineration residues, and deodorizing and sterilizing microorganisms. Sludge solidified fire and an artificial soil manufacturing method using the same.

Sewage sludge with high moisture content is a representative environmental pollutant, and has been conventionally treated by ocean dumping, landfilling, and the like, and various methods for restoring the environment contaminated by the pollutants are currently being prepared.

For example, sewage sludge discharged more than 6,000 tons per day has been banned from landfills since July 2003, and even the most easily disposed of dumping at sea is a London dumping treaty.

In particular, Korea, which has a narrow territory, should urgently seek efficient and safe treatment methods to prevent pollution of the surrounding environment and to prevent contamination of the leachate from sludge.

Currently, local governments around the country, including metropolitan landfills, are preparing treatment facilities for solidifying high-function sludge to produce artificial soils that can be used as various ground materials such as cover soil, fill soil, soft ground improvement material, draft material, and backfill material. In this regard, as the solidification treatment of the sludge with moisture is efficiently carried out, it is important to develop an excellent solidified material in terms of productivity and economic efficiency.

Conventional research on sewage sludge solidified fires has caused problems of odor and reslurrying due to the use of strongly alkaline materials such as quicklime and cement, and additionally added expensive acidic materials such as sulfuric acid and iron sulfate to supplement them. In order to reduce ammonia emission, the price of raw materials to be added is high and economic efficiency is insufficient. In addition, attempts to solve the problem through the drying and curing of the treatment apparatus to compensate for the defects due to the characteristics of the material described above, but the treatment itself has a structure that causes a high cost and it is difficult to smoothly operate the heating curing plant.

The present invention has been made to solve the above problems, an object of the present invention is to reduce the water content of sewage sludge by absorbing and exothermic action of CaO contained in a large amount of incineration residues, sewage sludge deodorization and microorganisms are sterilized It is to provide a solid fire and artificial soil manufacturing method using the same.

In order to solve the above technical problem, sewage sludge solidified material according to the present invention is fly ash having a calcium oxide content of 0.1 to 5% based on 100 parts by weight of the incineration residue having a calcium oxide (CaO) content of 20% to 70%. (fly ash) 5 to 50 parts by weight.

In addition, the incineration residue is one or a mixture of two or more selected from the group consisting of coal ash, biomass incineration residue, sewage sludge incineration residue, paper sludge incineration residue, RDF (Refuse Derived Fuel) incineration residue and RPF (Refuse Plastic Fuel) incineration residue. Is preferably.

In addition, the incineration residues preferably have a specific surface area of 2,500 to 6,000 cm 2 / g.

In addition, the fly ash preferably has an unburned carbon content of 8% or more.

In addition, it is preferable that a strength expression agent is further included in order to prevent re-slurrying of solids produced by solidifying sewage sludge.

In addition, the strength expression agent is preferably a mixture of fine slag powder and sulfate stimulant.

In addition, the slag fine powder is preferably any one or a mixture of two or more selected from the group consisting of blast furnace slag fine powder, stainless steel slag fine powder and copper smelting fine powder.

It is preferable that the sulfate stimulant is any one selected from calcium sulfate, aluminum sulfate, magnesium sulfate and sodium sulfate, or a mixture of two or more thereof.

In addition, the strength expression agent is preferably mixed 5 to 50 parts by weight based on 100 parts by weight of the incineration residue.

In addition, it is preferable to further include a solidification accelerator in order to promote the sewage sludge to solidify as soon as possible.

In addition, the solidification accelerator is preferably any one or a mixture of two or more selected from the group consisting of calcium aluminate cement, calcium sulfur aluminate cement, alumina cement and cemented carbide.

In addition, the solidification accelerator is preferably mixed with 0.1 to 10 parts by weight based on 100 parts by weight of the incineration residue.

In addition, in order to prevent the solidified material or sewage sludge solidified in the manufacturing process in the process of manufacturing or transporting the solids produced by the solidification is preferably further included an anti-sticking agent.

In addition, the anti-sticking agent is preferably any one or a mixture of two or more selected from the group consisting of limestone fine powder, feldspar fine powder, silica fine powder and granite fine powder.

In addition, the anti-sticking agent is preferably mixed 10 to 100 parts by weight based on 100 parts by weight of the incineration residue.

Artificial soil manufacturing method according to the present invention comprises the steps of 1) preparing the solidified material; 2) mixing 5 to 100 parts by weight of the solidified material with respect to 100 parts by weight of sewage sludge; And 3) curing the mixture of the sewage sludge and the solidified material.

In addition, step 3) is preferably carried out by room temperature curing or heating curing the mixture.

In addition, step 3) is preferably performed until the water content of the mixture is less than 60%.

According to the present invention, there is an effect of reducing the water content of sewage sludge by using CaO contained in a large amount in the incineration residue.

In particular, the exothermic effect of CaO has the effect of evaporating moisture.

In addition, porous incineration residue and unburned carbon present in fly ash have an effect of adsorbing and deodorizing ammonia gas.

In addition, it is also effective to sterilize the microorganisms contained in the sewage sludge by initially maintained at pH 12 or more.

1 is a photograph of the specimen formed by compressing the artificial soil produced by the present invention.
2a to 2c show the uniaxial compressive strength of the artificial soil prepared by Examples 1 to 3, respectively.
Figure 3a is an electron micrograph of the sewage sludge before mixing the solid fire, Figure 3b is an electron micrograph of the artificial soil prepared by Example 3.
4A to 4C show the permeability coefficients of the artificial soils prepared by Examples 1 to 3, respectively.

Hereinafter, the sewage sludge solidified material according to the present invention and a manufacturing method of artificial soil using the same will be described in detail.

First, the components and actions of the sewage sludge solidified material according to the present invention will be described.

The sewage sludge solidified material according to the present invention includes an incineration residue having a calcium oxide (CaO) content of 20% to 70%, and a fly ash having a calcium oxide content of less than 0.1 to 5%.

Calcium oxide contained in a large amount in the incineration residue reacts with water to be absorbed, exothermic, and expand to form calcium hydroxide. The reaction scheme is as follows.

CaO + H ₂ O-> Ca (OH) ₂ + 15.6㎉ mol ^-1

Although incineration residues are generally recycled to concrete admixtures, incineration residues containing a large amount of calcium oxide are incapable of being used as concrete admixtures because of their absorption, heat generation, and expansion characteristics.

Therefore, the present invention is to use incineration residues that can not be utilized as a concrete admixture.

That is, when the incineration residue containing a large amount of calcium oxide is mixed with the sewage sludge having a high water content, the water of the sewage sludge is reduced while calcium hydroxide is produced by the above reaction. In addition, since the heat generated by the above reaction evaporates the water of sewage sludge, it is possible to further reduce the water content of the sewage sludge.

On the other hand, incineration residues containing more than 20% of calcium oxide are coal ash, paper sludge incineration residue, biomass incineration residue, sewage sludge incineration residue, RDF incineration residue and RPF incineration residue.

It is preferable that the specific surface area of the said incineration residue is 2,500-6,000 cm <2> / g. When the specific surface area of the incineration residue is less than 2,500 cm 2 / g, the fine particles are insufficient to reduce the moisture content reduction effect when solidifying sewage sludge, and when the specific surface area is more than 6,000 cm 2 / g, the apparent density is lowered during the transfer of the solid material It is scattered during transportation and equipment operability is lowered.

Coal ash is produced in many power plants. In particular, coal ash produced in a power plant having a desulfurization method in a furnace has a high content of calcium oxide. In the furnace desulfurization method, coal and limestone are mixed and burned, so the coal ash contains a large amount of free CaO.

In contrast, coal ash produced in power plants with separate desulfurization facilities has less than 5% calcium oxide.

Table 1 shows the differences between coal ash in power plants with separate wet desulfurization equipment and coal ash in power plants by furnace desulfurization.

Item Power plant coal ash with separate desulfurization Power plant coal ash with furnace desulfurization Combustion fuel Coal (Import Bituminous Coal) Coal, limestone, waste tire (some power plants) Combustion temperature About 1350 ℃
-High combustion efficiency for economic power plant operation, reduction of coal ash generation rate and high quality coal ash discharge About 850 ℃
-Nitrogen emission reduction while decarbonation temperature range Exhaust Gas Desulfurization Facility Separate wet desulfurization facility Desulfurization Reaction with Limestone Mixture Exhaust gas denitrification plant Separate denitrification equipment Maintain low combustion temperatures and spray ammonia and other chemicals into boilers Chemical composition SiO _{2 ,} Al ₂ O _{3 ,} Fe ₂ O ₃ Due to limestone mixing
High free CaO component. Vitrification Degree high low Main recycling purpose Peak season with concrete admixture
Recycle all generation Clay substitute cement raw material,
Landfill of waste disposal site through long distance transportation Advantages and problems of using concrete admixture -Increased long-term strength with pozzolanic activity
- Improved workability
-Reduced unit quantity (durability, improved strength)
-Reduced heat of hydration (structure crack prevention) -Free CaO exothermic reaction
-Unit quantity increase (strength, durability decline)
-Increased heat of hydration (structure cracking)
-Reduced workability Etc KS L 5405 conformity product generation Do not satisfy the chemical composition and physical performance of KS L 5405

That is, the coal ash produced by the furnace desulfurization method contains a large amount of calcium oxide, but the coal ash produced in a facility equipped with a separate desulfurization device contains a very small amount of calcium oxide. Therefore, as described above, the coal ash produced in the facility equipped with a separate desulfurization device contains a small amount of calcium oxide can be recycled as a concrete admixture.

In other words, the incineration residue used in the solidified fire of the present invention is a coal ash produced by the desulfurization method with a high CaO content.

In addition, the fly ash is less than 5% calcium oxide content, the water absorption properties are relatively small compared to the incineration residues.

 Meanwhile, since the KS standard of fly ash for use as cement admixture is less than 5% of unburned carbon content, it is not suitable for use as a cement admixture, that is, fly ash with more than 12% of unburned carbon content at the time of occurrence. Or it is preferable to use a granulated fly ash having an unburned carbon content of 8% or more selected after purification. The unburned carbon contained in the fly ash is porous and has a property of adsorbing ammonia gas and heavy metal generated during solidification of sewage sludge.

Therefore, the solidified material of the present invention is to use the incineration residue and fly ash as the main raw material that can not be recycled as a concrete mixed material.

The mixing ratio of the incineration residue and fly ash is preferably 5 to 50 parts by weight with respect to 100 parts by weight of the incineration residue, but when the amount of fly ash is less than 5 parts by weight, the adsorption performance of ammonia and heavy metals is lowered. The water content reduction effect of sewage sludge is reduced.

In addition, the solidified material according to the present invention further comprises a strength expression agent in order to prevent the sewage sludge solidified and the resulting solids resludge, the strength expression agent is preferably a mixture of fine slag powder and sulfate stimulant.

In addition, the slag fine powder is any one selected from the group consisting of blast furnace slag fine powder, stainless steel slag fine powder and copper smelting fine powder, or a mixture of two or more thereof, and the sulphate stimulant is either one selected from calcium sulfate, aluminum sulfate, magnesium sulfate and sodium sulfate. It is preferable that it is a mixture of the above.

The strength expression at the early age according to the hydration reaction of the fine slag powder and the sulphate stimulant is achieved by the C-S-H gel produced simultaneously with a large amount of ettringite. In addition, the CSH gel surrounds Etringite. As the age elapses, the amount of the CSH gel continuously increases and the CSH gel tightly fills the pores of the cured paste, forming a dense network network structure with etringing, .

The strength expression agent is preferably mixed 5 to 50 parts by weight based on 100 parts by weight of the incineration residue. If the amount of the strength expression agent is less than 5 parts by weight, the amount of hydrate produced may be insufficient, and reslurrying may occur. If the amount is more than 50 parts by weight, the amount of hydrate is excessively increased and the strength is greatly increased. Can't use it.

In addition, the solidifying material according to the present invention may further contain a solidification accelerator such as calcium aluminate cement, calcium sulfur aluminate cement, alumina cement and cemented carbide. When the solidification accelerator is further mixed, sewage sludge solidifies as soon as possible, thereby exhibiting the strength of the solids in a short time, and thus making it possible to use it as a cover material.

In addition, in the solidified material according to the present invention, limestone, feldspar, silica, granite fine powder, and the like may be further mixed as an anti-sticking agent. This is to increase the productivity by preventing the solidified material or sewage sludge is fixed to the manufacturing equipment in the process of manufacturing or transporting the solids produced by solidification.

The amount of the anti-sticking agent is mixed in an amount of 10 to 100 parts by weight based on 100 parts by weight of the incineration residue. If the amount of the anti-sticking agent is less than 10 parts by weight with respect to 100 parts by weight of the incineration residue, there is no anti-sticking effect, and if it exceeds 100 parts by weight, the water content reduction effect is lowered.

Hereinafter will be described the artificial soil manufacturing method according to the present invention.

First, the above-mentioned solidified material is manufactured, and then 5-100 parts by weight of the solidified material is uniformly mixed with respect to 100 parts by weight of sewage sludge. If the solidified material is mixed at less than 5 parts by weight, the moisture content is not sufficiently reduced, so that it cannot be used as a cover material. If it is mixed at more than 100 parts by weight, the water content is too low, and solids are scattered and covering work becomes difficult.

Finally, the mixture of sewage sludge and solidified material is cured at room temperature or heated until the moisture content is 60% or less.

Example  One

First, 20 parts by weight of fly ash having an unburned carbon content of 11% and a calcium oxide content of 0.6% with respect to 100 parts by weight of coal ash having a calcium oxide content of 42% by furnace desulfurization, and 60 blast furnace slag fine powders as a strength expression agent 20 parts by weight of a mixture consisting of% and 40% by weight of calcium sulfate, 3 parts by weight of calcium aluminate cement as a solidifying accelerator, and 20 parts by weight of limestone as a fixing agent were uniformly mixed to prepare a solidified material.

Next, with respect to 100 parts by weight of sewage sludge having a water content of 80%, by mixing 30 parts by weight of the solidified material prepared as described above to produce room temperature curing artificial soil. Figure 1 shows that the specimen prepared by the artificial soil prepared in Example 1.

Example  2

With respect to 100 parts by weight of sewage sludge having a water content of 80%, 40 parts by weight of the same solidified material as in Example 1 was mixed at room temperature to prepare artificial soil.

Example  3

With respect to 100 parts by weight of sewage sludge having a water content of 80%, 50 parts by weight of the same solidified material as in Example 1 was mixed at room temperature to prepare artificial soil.

Performance Test Method and Result of Artificial Soil

As shown in Table 2 below, the water content was measured by the KS F 2306 method, and the compressive strength and permeability tests were performed by the KS F 2343 and KS F 2322 methods.

Experiment Way Remarks Water content KS F 2306 How to measure the water content of soil Compressive strength KS F 2343 Uniaxial compressive strength method Permeability coefficient KS F 2322 Variable Position Permeability Test

(1) water content change

The moisture content of the artificial soil prepared by Examples 1 to 3 according to time is shown in Table 3 below. As confirmed in Table 3, the water content of the sewage sludge before the solidified material mixture was 80%, it can be seen that the water content is rapidly reduced over time. The moisture content is greatly reduced because, as described above, the exothermic reaction occurs immediately after the solidified material is mixed with the sewage sludge and the hydration reaction proceeds simultaneously. In addition, the water content gradually decreases due to hydrate formation and natural drying over time. After 3 days of natural curing, it is expected to not only be easy to handle but also to increase the compressive strength.

division Immediately after improvement 3 hours 1 day 3 days 5 days 7 days Example 1 59.2% 56.8% 52.6% 48.2% 39.8% 34.2% Example 2 54.9% 50.2% 46.5% 39.1% 31.2% 26.1% Example 3 51.3% 47.3% 40.1% 34.1% 24.2% 13.2%

(2) Uniaxial compressive strength  change

2A to 2C show changes in the uniaxial compressive strength of artificial soils prepared by Examples 1 to 3, respectively. As can be seen through the 7 days of curing, Example 1 was 3.74kgf / cm ² , Example 2 was 7.02kgf / cm ² , Example 3 was shown to increase to 8.91kgf / cm ² . This is much higher than 0.5kgf / cm ² and 1.0kgf / cm ² , which are the strength standards of cover and fill materials, and showed strength expression that can be used for various ground materials such as soft ground improvement material, water repellent material, and backfill material. . When mixed with solidified materials, this results in water reduction and surface modification of sewage sludge due to absorption heat generation, resulting in unity of particles, resulting in consolidation promoting effect, and calcium silicate reaction induced by CaO and SiO ₂ components to increase compressive strength. This is because the solidification reaction that can be secured occurs to increase the strength. In addition, the water content of sewage sludge is relatively lower due to the absorbency of the solidified material, and the clay and colloidal components, which are fine particles are separated by the absorbent and ion exchange, pozzolanic and carbonation reaction of the solidified material, and the particle size distribution is changed accordingly to improve the quality soil. Uniaxial compressive strength is increased.

Figure 3a shows the microstructure of the sewage sludge before mixing with the solidified material, Figure 3b shows the microstructure of the artificial soil prepared by Example 3. As can be seen through this, the sewage sludge before solidification has a sponge-like structure in which the particle shape is not clearly observed and the moisture contained therein is difficult to discharge, whereas the artificial soil prepared by the present invention is composed of acetrite of acicular crystal and Many reaction products of honeycomb CSH gels have been observed.

(3) before and after immersion Uniaxial compressive strength  change

When the artificial soil manufactured by the present invention is used as a daily cover material for landfills, it must have the required strength and at the same time, the reslurrification phenomenon and the strength reduction phenomenon caused by the inundation such as heavy rain and heavy snow, which are the climatic characteristics of Korea, should not occur. something to do. Therefore, in this experiment, the uniaxial compressive strength changes before and after 1 day immersion were investigated for artificial soils cured for 7 days.

The change in uniaxial compressive strength before and after immersion is shown in Table 4 below. As can be seen through this, the artificial soil prepared by Example 1 is -0.26kg / kg / cm ² , and the artificial soil prepared by Example 2 is -0.41kg / cm ² , which is prepared by Example 3 Artificial soils showed a change rate of -0.93 kg / cm ² .

As can be seen from the above results, the change in uniaxial compressive strength before and after immersion of artificial soils by the mixing ratio of solidified materials showed a relatively small reduction rate. It seems that absorption does not occur. Therefore, when the artificial soil prepared by the present invention is used in landfill, reslurrying or strength reduction phenomenon due to flooding due to snowfall is insignificant. do.

Strength expression at early age following solid fire input is achieved by CSH gel in which the strength-expressing agent simultaneously forms a large amount of ethringite. In addition, the CSH gel hardly fills the voids of the cured paste to form a dense networked network with ettringite, and continuously expresses high strength. Therefore, if the content of the strength-expressing agent is increased according to the use of the solidified, it can express the strength that can be utilized not only for the cover material but also for various ground materials such as the fill material, the order material, and the backfill material.

Before immersion (kg / ㎠) After immersion (kg / ㎠) Intensity change Example 1 3.74 3.48 ▽ 0.26 Example 2 7.02 6.61 ▽ 0.41 Example 3 8.91 7.98 ▽ 0.93

Example 4

First, 20 parts by weight of fly ash having an unburned carbon content of 11% and a calcium oxide content of 0.6% with respect to 100 parts by weight of coal ash having a calcium oxide content of 42% by furnace desulfurization, and 3 weights of calcium aluminate cement as a solidification accelerator Parts and 20 parts by weight of limestone as a sticking inhibitor was uniformly mixed to prepare a solidified material.

Next, with respect to 100 parts by weight of sewage sludge having a water content of 80%, by mixing 30 parts by weight of the solidified material prepared as described above to produce room temperature curing artificial soil.

That is, when compared with Example 1, there is a difference that the strength expression agent is not mixed.

Example 7 an example in the age compressive strength of 1.87kgf / cm ² to the reference intensity of boktojae and seongtojae 0.5kgf / cm ² and a strength higher than 1.0kgf / cm ² I incorporation of Examples 1 to 4 Compared to 3, the strength was slightly decreased.

(4) Permeability characteristics

4A to 4C show the permeability coefficients of the artificial soils prepared by Examples 1 to 3, respectively. Permeability coefficient is also increased under the same conditions as the compressive strength is increased when the mixing ratio of solidified fire to the sewage sludge is increased to 30% (Example 1), 40% (Example 2), 50% (Example 3). At 7 days of age, Example 1 gradually decreased to 1.62 × 10 ⁻⁶ , Example 2 to 2.12 × 10 ⁻⁸ , and Example 3 to 1.01 × 10 ⁻⁸ , respectively. If you look at the national standard for permeability of cover material, the waste management law only specifies the thickness of the cover material, but it does not provide any specific standard. However, in the Middlesex country of New Jersey, the permeability coefficient of landfill cover is 1 × 10 ^-3. In view of what is presented in cm / sec to 1 × 10 ⁻⁷ cm / sec, the artificial soil prepared by the present invention is considered to have a sufficient permeability function as a landfill daily and intermediate cover material.

(5) pH  change

The pH change according to the natural curing date of the mixture of sewage sludge and solidified materials is shown in Table 5. As a result of the experiment, strong alkali was changed from pH 4 ~ 5, pH8.9 ~ 9.1, from the point of physical change of sewage sludge to 4 ~ 5 days, which can minimize the environmental pollution caused by pH. It is thought to act as an inhibitor.

In the solidified material according to the present invention, the CaO reacts with water and is transferred to Ca (OH) ₂ , and the solids exhibit a strong alkali state. However, as the curing process proceeds, the hydration of Ca (OH) ₂ fly ash and fine slag powder is performed. It is thought to gradually change to a weak alkali state as the pH is lowered gradually.

Immediately after mixing 3 hours after mixing 1 day 3 days 5 days 7 days 9th 11th 13th Example 1 12.1 11.6 11.6 11.5 10.5 9.3 9.2 9.1 8.9 Example 2 12.1 11.7 11.7 11.4 10.5 9.5 9.3 9.2 9.1 Example 3 12.2 11.8 11.7 11.5 10.6 9.3 9.4 9.3 9.2

(5) Odor control (ammonia)

Sewage sludge mainly produces odors due to the decomposition of organic matter. As the pH rises, the activity of microorganisms decreases and the decomposition of organic matter in the sludge is also stopped, resulting in the inherent odor of sewage sludge. However, when the quicklime and sewage sludge are mixed, severe odor is generated, which is the biggest problem in the lime stabilization process with ammonia gas which is rapidly released as the pH rises.

This is because the ammonia present in the soluble ammonium ion state in the neutral region is released as the nonionic ammonia gas with the rise of pH.

In order to evaluate the odor control ability of the solidified fire according to the present invention, the artificial soil prepared by Example 3 and the artificial soil prepared by Comparative Example 1 below, which is a conventional general artificial soil manufacturing method, are tested. Table 6 shows.

Comparative Example 1

With respect to 100 parts by weight of sewage sludge having a water content of 80%, 20 parts by weight of fly ash, 10 parts by weight of quicklime, and 20 parts by weight of cement were mixed to prepare room temperature and artificial soil.

According to Example 3, ammonia odors of about 180 ppm of surface and 220 ppm of internal ammonia were detected immediately after mixing of sewage sludge and solidified fire, and gradually decreased over time. After 6 hours, the surface was 10 ppm of average and 30 ppm of internal average. It decreased to about below.

In Comparative Example 1, the result was initially close to 1,000 ppm, which is the detection range of the detection tube on the surface and the inside, and gradually decreased thereafter, after 72 hours, the surface was 80 ppm and the interior was 120 ppm, resulting in odor of the artificial soil according to the present invention. The degradation performance was confirmed. This is thought to be controlled through a physical adsorption mechanism due to microporous particles such as unburned carbon contained in the solidified material of the present invention.

(6) heavy metal elution

Table 7 below shows the heavy metal elution test results of the artificial soil prepared by Example 1. As can be seen from this, most of heavy metals were not eluted, and when applied to the waste dissolution test method in Korea, trace amounts of lead, mercury, and arsenic were detected, but the environmental standards were satisfied. This is because the heavy metal is substituted or fixed into the crystal structure by being fixed by the hydrate generated in the hydration reaction. Therefore, the dissolution concentration in all these experiments is much lower than the standard value or is not detected. Therefore, secondary pollution due to heavy metal leaching will not be a concern even if the sewage sludge is solidified and used as daily cover material for landfill.

(7) Small model test evaluation to evaluate the stability of cover material in landfill

Small model test is to test performance performance of cover material during actual landfill. A cylinder of diameter 10cm and height 15cm is made, and a valve is installed at the lower 4cm part, and solidified sewage sludge is put in the upper 11cm space. After mixing, adjust the ratio at 25, 30, 35, 40, and 45%, and after 28 days, apply the condensation test with a compression tester to calculate the strength and test the COD, pH, and heavy metal content of the effluent flowing down. And organic matter content was measured.

As a result, environmental engineering experiments such as pH, organic matter, heavy metal elution, BOD and COD showed weak alkalinity with pH of 7.7, and heavy metal elution was (Cd, Cu, Pb, Cr, Zn) between 0.00102 and 0.3427. The Enforcement Rule, Leachate Emission Standard, was satisfied. In addition, BOD and COD also satisfies the 150 mg / L and 70 mg / L values specified in the Waste Management Act.

(8) To evaluate the settlement of cover material at landfill Earthwork Test

Soil test was conducted to analyze the settlement amount of cover material at the time of landfill using 105 cm high, 42 cm wide and 78 cm long. Up to 500kg was loaded to observe the load and settlement over time. The results of the soil test showed that almost all settlements occurred within 80 hours. In other words, the artificial soil produced by the present invention is not settled long enough to be used as a landfill cover material.

As a result of all experiments, the artificial soil produced by the present invention can be said to be highly applicable as cover soil and landfill material. The results are summarized in Table 8 below.

division  Performance of this product Mixture appearance Natural ocher Reslurry None (after 7 days of age) Ammonia odor 30ppm or less
(3 hours after curing, 10 cm of mixture surface) pH After ejecting? Day 3: pH 11.5? 12
After 3 days: pH 9? 10.5 Moisture content 47 56% (3 hours after mixing) Uniaxial compressive strength Suitable (about 3 9 kgf / cm ² , 7 days of age) Heavy metal elution Appropriate (age 7 days, baseline 1/10 or less) Small model test (BOD, COD) BOD 10 or less (baseline 150 mg / L)
COD 40 or less (reference value 70 mg / L) Earthwork Experiment Almost all settlements occur within 80 hours

Claims (18)

It includes 5 to 50 parts by weight of fly ash having a calcium oxide content of 0.1 to 5% by weight based on 100 parts by weight of the incineration residue having a calcium oxide (CaO) content of 20 to 70% by weight.
The fly ash sewage sludge solidified material, characterized in that the unburned carbon content is 8% by weight or more.
The method of claim 1,
The incineration residue is any one or a mixture of two or more selected from the group consisting of coal ash, biomass incineration residue, sewage sludge incineration residue, paper sludge incineration residue, RDF (Refuse Derived Fuel) incineration residue and RPF (Refuse Plastic Fuel) incineration residue. Sewage sludge solidified fire, characterized in that.
The method of claim 2,
The incineration residue is sewage sludge solidified material, characterized in that the specific surface area of 2,500 ~ 6,000 ㎠ / g.
delete delete delete delete delete delete The method of claim 1,
Sewage sludge solidified material further comprises a solidification accelerator for promoting the sewage sludge to solidify as soon as possible.
The method of claim 10,
The solidification accelerator is sewage sludge solidified material, characterized in that any one or a mixture of two or more selected from the group consisting of calcium aluminate cement, calcium sulfur aluminate cement, alumina cement and cemented carbide cement.
The method of claim 11,
The solidification accelerator is sewage sludge solidified material, characterized in that mixed 0.1 to 10 parts by weight based on 100 parts by weight of the incineration residue.
The method of claim 1,
Sewage sludge solidified material further comprises an anti-sticking agent to prevent the solidified material or sewage sludge solidified in the manufacturing equipment in the process of manufacturing or transporting the solids produced by solidification.
The method of claim 13,
The anti-sticking agent is sewage sludge solidified material, characterized in that any one or a mixture of two or more selected from the group consisting of limestone fine powder, feldspar fine powder, silica fine powder and granite fine powder.
15. The method of claim 14,
The anti-sticking agent is sewage sludge solidified material, characterized in that mixed 10 to 100 parts by weight based on 100 parts by weight of the incineration residue.
1) preparing a solidified material according to any one of claims 1 to 3, 10 to 15;
2) mixing 5 to 100 parts by weight of the solidified material with respect to 100 parts by weight of sewage sludge; And
3) curing the mixture of the sewage sludge and solidified material; artificial soil manufacturing method comprising a.
17. The method of claim 16,
Step 3) is artificial soil manufacturing method characterized in that the mixture is carried out at room temperature curing or heating curing.
17. The method of claim 16,
Step 3) is the artificial soil production method, characterized in that carried out until the water content of the mixture is less than 60% by weight.

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