KR100699925B1 - Artificial landfill cover method thereof to use seawage sludge - Google Patents

Abstract

Provided is a preparation method of environment-friendly artificial landfill cover materials using industrial by-products such as sewage sludge, waste plaster, and waste silica to thus prevent waste in resources and environment contamination. The preparation method of artificial landfill cover materials comprises the steps of: mixing 100 wt% of sewage sludge and 5-30 wt% of quicklime for solidifying the sewage sludge; adding a porous deodorant at an amount of 10-50% by weight of 100% of the sewage sludge; and adding a mixture of waste plaster and waste silica mixed at a ratio of 1:0.7 to the sewage sludge solid at an amount of 10-30% by weight of 100% of the sewage sludge. The deodorant is used to remove ammonia gas generated during use of the quicklime.

Description

Eco-friendly landfill artificial cover material manufacturing method using industrial by-products {Artificial landfill cover method about to use seawage sludge}

The present invention relates to a cover material of a waste landfill where recycled industrial by-products such as dewatered sludge (water content of 80 to 85%) generated in a sewage treatment plant are mixed with a solid agent, and in particular, by solidifying after mixing industrial waste in sludge. The water content is 40 to 42% or less after the hydration reaction and curing, the drying efficiency is very high, and relates to an environmentally friendly landfill artificial cover material manufacturing method using industrial by-products that are not harmful by heavy metals, microorganisms and the like.

In Korea, the amount of sludge generated in 70 sewage treatment plants in 1996 was 1.28 million tons, 1.9 million tons in 2001, 2.07 million tons in 2003, and 2.27 million tons in 2003. If sludge is generated, 2.85 million tons will be generated in 2006. 45,000 tonnes, or 3.5% of the sludge generated, are recycled and the rest is disposed of by landfill or ocean dumping. As such, the final sludge waste has been treated mainly by landfilling and dumping, and some are recycled. It is used for composting.

On the other hand, sludge has a high water content, so it is highly perishable, there is a contamination problem of pathogens, depleting dissolved oxygen and reducing the soil to reduce the various effects must be treated. However, in the case of reclamation, the biggest challenge is to secure landfills, and when the sludge is reclaimed, workability is poor and various harmful heavy metals contained in the sludge remain in the soil, contaminating groundwater and surface water and causing an increase in leachate. Done.

For this reason, research on the recycling of sewage sludge has been actively conducted in recent years. The sludge recycling method can be largely classified into a technology using organic material and a technology using inorganic material. Among them, the use of organic materials includes pyrolysis, liquefaction, solid fuelization, and composting, and the recycling technology of inorganic materials can be recycled using light aggregate, brick, molten slag, and cover material.

In particular, the use of cover material, which is one of the above useful treatment methods, is a narrow country, and considering the domestic reality that it is difficult to secure landfill and stable soil for cover, development and commercialization of substitute cover material to replace soil is an existing landfill. Has a very important meaning in terms of extending the life span and preventing environmental pollution and economical aspects. In addition, if the prerequisite that ideal sludge recycling should not affect the human body and the environment is met, recycling of sludge is very important in terms of economic and environmental aspects.

Recently, various techniques have been proposed to recycle sewage sludge as cover material by adding various solidifying agents to the sewage sludge generated in the sewage treatment plant.

Among them, Korean Patent Laid-Open Publication No. 2000-25028 discloses a technique of mixing gypsum, quicklime, cement, and the like into sewage sludge as a special hardening agent, heating it to 500 ° C. or lower, and cooling it in the air as landfill soil.

However, in the conventional method using cement and quicklime as a solidifying agent, exothermic reactions occur in the process of mixing sewage sludge and additives, curing and drying. There is a problem that occurs. In addition, there is a problem such as securing a site for the solidification treatment, to solve problems such as minimizing soil pollution due to recycling.

The present invention is to solve the conventional problems as described above, to meet the purpose as a cover material, such as soil mechanical strength, permeability coefficient in the sewage sludge, and at the same time can minimize the odor generated when creating the cover material, pH 12 The purpose of the present invention is to provide an environmentally friendly landfill artificial cover material manufacturing method using industrial by-products that can induce the killing of pathogenic microorganisms such as Escherichia coli and provide a hygienic working environment to workers.

As a specific means for achieving the above object, the present invention, quantitative mixing of quicklime within the range of 5 to 30 parts by weight of quicklime with respect to 100 parts by weight of sewage sludge so as to solidify and recycle sewage sludge and organic matter contained in the sewage sludge. Solidifying step to solidify the sewage sludge; Deodorant mixing step of quantitatively mixing the porous odor control deodorant in the range of 10 to 50 parts by weight based on 100 parts by weight of the sewage sludge to the sewage sludge solidified through the solidification step; The waste mixing step of mixing the waste gypsum and silica in a ratio of 1: 0.7 by weight ratio of 10 to 30 parts by weight with respect to 100 parts by weight of sewage sludge before mixing the quicklime; It provides an environmentally friendly landfill artificial cover material manufacturing method using by-products and artificial cover material manufactured by the method.

Here, according to an embodiment of the present invention, the odor control deodorant, 100 parts by weight of any one selected from the treatment plant sludge, fly ash, waste silica of the alum series, phosphoric acid (K3PO4, KH2PO4, K2HPO4, NH4H2PO4 compared to the treatment) , One of H 3 PO 4) 10 to 50 parts by weight, the mixing step of mixing 100 parts by weight of water with respect to the treated material, respectively, and the mixture is stirred by stirring for 1 to 3 hours to maintain a temperature of 80 ~ 150 ℃ And a reaction step of evaporating only the moisture of the mixture, and a reaction step of cooling the reactant through a stirrer at room temperature for 1 to 3 hours when the reaction is completed and 100% of the water contained in the reactant to completely evaporate when the cooling is completed. It is characterized in that it is manufactured through a drying step of obtaining a deodorant which is the final product by drying in a dryer of maintained condition of ~ 300 ℃.

Hereinafter, an environmentally friendly landfill artificial cover material manufacturing method using industrial by-products according to a preferred embodiment of the present invention will be described in detail.

In the method of manufacturing landfill artificial cover material according to the present invention, a solidifying step of solidifying by mixing an appropriate amount of quicklime with sewage sludge having a water content of 80 to 85%, and a porous odor control deodorant to the sewage sludge solidified through the solidification step Deodorant mixing step of mixing quantitatively, and waste mixing step of quantitatively mixing the mixture of waste gypsum and waste silica in an appropriate ratio within the range of 10 to 30 parts by weight based on 100 parts by weight of sewage sludge before mixing the quicklime.

Referring to the manufacturing method according to the present invention in more detail for each step as follows.

The solidification step is a process of solidifying sewage sludge and the organic matter contained in the sewage sludge by mixing an appropriate amount of quicklime with sewage sludge having a water content of 80 to 85%.

Here, the quicklime reacts quickly with sewage sludge, shortens the solidification time, increases productivity, and effectively solves imbalances and safety problems of soil components due to direct landfilling of organic matter, and also induces high temperature and exothermic reactions of sludge. It is added for the purpose of drying the sewage sludge to increase the strength and permeability coefficient due to the solidification reaction.

The mixing amount of the quicklime mixed in this process is preferably mixed in consideration of the water content and the organic content of the sewage sludge, according to this embodiment, the water content of 80% to 85% to some extent dehydrated sewage sludge 100 5 to 30 parts by weight of the parts by weight is mixed quantitatively.

Here, the mixing amount of quicklime with respect to 100 parts by weight of sewage sludge is the optimum compaction ratio for proper function control, the reaction of high heat and exothermic reaction when the mixing ratio of quicklime is added less than 5 parts by weight with respect to 100 parts by weight of sewage sludge In addition, the water-drying effect cannot be expected, and if it is added in excess of 30 parts by weight, the strength and density of the cover material after the solidification reaction are higher than expected, resulting in a problem of remarkably inferior permeability, so 5 to 30 parts by weight for 100 parts by weight of sewage sludge. It is preferable to quantitatively mix the parts.

The deodorant mixing step is a process of quantitatively mixing the porous odor control deodorant with the sewage sludge solidified through the solidification step by adsorbing and fixing ammonia gas generated during quicklime mixing in the solidification step to control odor.

Here, the porous odor control deodorant proposed in the Republic of Korea Patent Application No. 2006-82194 (name: manufacturing method for removing odor generated when sewage sludge solidified and the deodorant produced there) previously filed by the present applicant Deodorants may be used.

Specifically, the malodor control deodorant, 100 parts by weight of any one selected from the treatment plant sludge, fly ash, waste silica of the column series, phosphoric acid (K3PO4, KH2PO4, K2HPO4, NH4H2PO4, H3PO4) relative to the treatment 10 ~ 50 parts by weight, the mixing step of mixing 100 parts by weight of water with respect to the treatment, and the mixture is reacted by stirring through a stirrer for 1 to 3 hours, maintaining a temperature of 80 ~ 150 ℃ only water of the mixture The reaction step of evaporation, and when the reaction is complete, the reaction step is cooled by stirring the stirrer at room temperature for 1 to 3 hours and cooled, and when the cooling is completed is maintained at 100 ~ 300 ℃ to completely evaporate the water contained in the reactant It can be obtained through a drying step of drying in a dryer of conditions to obtain the final deodorant.

The amount of the malodor control deodorant mixed in this process is preferably 10 to 50 parts by weight based on 100 parts by weight of the sewage sludge. If the odor control deodorant is added less than 10 parts by weight based on 100 parts by weight of sewage sludge, there is a problem in controlling the ammonia gas, which is a malodorous substance. This is because less than 35% of the water is required to be re-controlled during later cover work.

On the other hand, the waste mixing step is a step of quantitatively mixing the industrial by-products in the above-described mixture of the quicklime and the odor control deodorant for the purpose of having the final product cover material having a suitable strength and permeability coefficient.

The industrial by-product is preferably a mixture of waste gypsum and waste silica in a quantitative ratio, and more preferably a mixture of waste gypsum and waste silica in a weight ratio of 1: 0.7.

Here, the waste gypsum (waste titanium gypsum produced in the titanium manufacturing process) and the waste silica is added to the purpose of suppressing the soil mechanical strength, permeability coefficient, leaching of heavy metals of this final cover material and to minimize the generation of odor when the cover material is produced. A solidification and malodor control deodorant mixing step is added to the solidified sewage sludge solidified form.

The mixing amount of the mixture of the waste gypsum and waste silica mixed in this process is preferably 10 to 30 parts by weight compared to 100 parts by weight of the sewage sludge.

Here, when added to less than 10 parts by weight with respect to 100 parts by weight of sewage sludge, the moisture content of the finally produced cover material becomes high to facilitate the storage and transportation, and when it exceeds 100 parts by weight, the viscosity of the mixed material falls to cracks It is preferable to mix within the above weight part range because it may cause problems in the expression of compressive strength and the permeability coefficient.

Hereinafter, the operation and effects of the present invention will be described through specific examples and comparative examples.

<Example>

100 parts by weight of sewage sludge is weighed into 10 parts by weight of quicklime, mixed and measured in and out of ammonia through a gas test tube.

Then, 20 parts by weight of the above-described odor control deodorant, which is a porous material, to 100 parts by weight of sewage sludge before mixing quicklime is mixed into the sewage sludge mixed with quicklime, and waste gypsum (waste phosphate, waste titanium gypsum, etc.) is added thereto. ) And 20% by weight of the industrial by-product mixture containing waste silica in a ratio of 1: 0.7 by weight based on 100 parts by weight of sewage sludge prior to mixing the quicklime.

At this time, the sewage sludge of the composition used is 60% to 70% of the organic matter, SiO ₂ in the inorganic material occupies the highest ratio of 17.78%, Next, Al ₂ O ₃ 7.42%, P ₂ O ₅ 3.81 Included in% order. In the quicklime, CaO was the highest at 68.84% and SiO ₂ was 7.20%.

Comparative Example

20 parts by weight of cement and 10 parts by weight of quicklime were mixed in 100 parts by weight of sewage sludge having a water content of 80 to 85%.

Table 1 below is a result of measuring the compressive strength and pH change according to the elapsed time at normal room temperature for the final product, that is, the cover material, according to the examples and comparative examples of the present invention.

division Comparative example Example 1 day Strength (㎏ / ㎠) 1.58 1.87 pH 13.56 11.84 3 days Strength (㎏ / ㎠) 2.67 3.2 pH 13.12 11.79 7 days Strength (㎏ / ㎠) 5.64 7.02 pH 13.02 9.68

As can be seen from Table 1, according to an embodiment of the present invention, the uniaxial compressive strength satisfies 0.5 kg / cm 2 or more, which is a strength recommendation value that can be used as a cover material from 1 to 7 days, and pH As can be seen from the results that can be maintained for 12 days or 3 days, it is within the range that can induce the killing of harmful bacteria such as Escherichia coli.

On the other hand, according to the comparative example, it is impossible to use it as pH 12.5 or more from 1 day to 7 days whose pH is designated as waste by waste management law.

<Table 2> is a result of measuring the change in the coefficient of permeability of the cover material according to the examples and comparative examples of the present invention described above.

division Comparative example Example 1 day 5.75 × 10 ^-6 7.67 × 10 ^-6 3 days 5.47 × 10 ^-6 4.56 × 10 ^-7 7 days 4.27 × 10 ^-6 1.02 × 10 ^-7

In case of permeability coefficient, there is no special requirement for permeability coefficient of cover soil recycled from domestic sewage sludge, but the design application condition of permeability coefficient for cover layer of domestic metropolitan landfill infrastructure construction project is 5 × 10 ^-5 ㎝ / s. Suggesting. As can be seen from the above table when looking at this standard, according to an embodiment of the present invention, permeability coefficient based on 1, 3, 7 days 7.67 × 10 ^-6 to It is 1.02 × 10 ^−7, which satisfies the design application conditions of the permeability coefficient.

<Table 3> is the result of measuring the degree of odor occurrence according to the time elapse of the cover material according to the embodiment and the comparative example of the present invention described above.

Compounding time Comparative example Example 1cm surface inside 1cm surface inside Early 1,500 1,800 10 30 1hr 1,500 1,800 10 25 3hr 670 1,500 5 20 6hr 620 850 5 10 12hr 500 720 5 5 24hr 370 550 5 5 72hr 250 400 5 5

As can be seen from the above <Table 3>, in the case of the comparative example of the existing solidification method, a high concentration of ammonia gas is generated to induce a severe odor can be for the operator's environment. However, in the case of the embodiment of the present invention mixed with the malodor control deodorant is a porous material, it was shown that the ammonia concentration has a significantly lower physical properties even on the surface 1cm and inside.

According to the present invention as described above, in accordance with the purpose as a soil mechanical / environmental engineering cover material in sewage sludge can minimize the odor generated when the cover material is produced, by maintaining the pH of about 12 to induce the death of pathogenic microorganisms Provide a hygienic working environment for workers.

In addition, when the water content is about 40 to 45 ± 5%, natural air drying for about 1 to 2 days to ensure the workability of the vehicle and equipment, it is possible to improve the utility as a cover material that is harmless to the human body because no harmful substances are eluted. As a result, there is an effect that can prevent the waste of resources and environmental pollution, and there is an advantage that can be manufactured at a lower cost than the hardener.

In addition, the concentration of this ammonia can be significantly reduced when mixed with ammonia is a very useful invention that can effectively solve the environmental pollution problem caused by ammonia odor when solidified to recycle sewage sludge.

Claims (3)

delete A solidification step of solidifying sewage sludge by quantitatively mixing quicklime within 5 to 30 parts by weight with respect to 100 parts by weight of sewage sludge so as to solidify and recycle the sewage sludge and organic matter contained in the sewage sludge; Deodorant mixing step of quantitatively mixing the porous odor control deodorant in the range of 10 to 50 parts by weight based on 100 parts by weight of the sewage sludge to the sewage sludge solidified through the solidification step; And a waste mixing step of quantitatively mixing the mixture of waste gypsum and waste silica in a weight ratio of 1: 0.7 within a range of 10 to 30 parts by weight based on 100 parts by weight of sewage sludge before mixing the quicklime. The malodor control deodorant 100 parts by weight of any one selected from alum-based water treatment plant sludge, fly ash, waste silica, 10 to 50 parts by weight of phosphoric acid (one of K3PO4, KH2PO4, K2HPO4, NH4H2PO4, H3PO4) compared to the treatment, compared to the treatment A mixing step of mixing 100 parts by weight of water, and reacting the mixture by stirring through a stirrer for 1 to 3 hours, maintaining a temperature of 80 to 150 ° C. and evaporating only the moisture of the mixture, and the reaction is completed. When the reactants are stirred by using a stirrer at room temperature for 1 to 3 hours to cool and when the cooling is completed, the final product is dried in a drier at 100 to 300 ° C. in order to completely evaporate the moisture contained in the reactants. Eco-friendly landfill artificial cover material manufacturing method using industrial by-products, characterized in that obtained through a drying step to obtain. delete