KR101825075B1 - Method for solidification of sewage sludge and solidified material using the same - Google Patents

Abstract

The present invention provides technology for recycling sewage sludge and technology for manufacturing a solidified material without bad smell, having excellent strength during a sludge recycling procedure. A sewage sludge solidification method includes: a sludge sterilizing step of sterilizing sewage sludge with microwaves; a solidifier mixing step of mixing the sludge, which has been sterilized through the sterilizing step, with a solidifier and mixing water; a solidifier blending step of blending the mixed material which has been made through the solidifier mixing step; and a curing step of curing the blended material which has been completely blended through the solidifier blending step. According to the present invention, sewage sludge is able to be sterilized through microwave sterilization, high strength stabilized soil is able to be produced, and leachate is prevented and foul odors are suppressed. According to the present invention, the sewage sludge solidifying method satisfies every certification item of quality certification standards (GR M 9020-2016) for excellent recycling products of solidified materials for quarry closed restoration, and thus, the use of waste resources is able to be improved through the recycling of sewage sludge and an eco-friendly and economical sludge treatment solution is suggested to make a contribution to environmental protection.

Description

[0001] METHOD FOR SOLIDIFICATION OF SEWAGE SLUDGE AND SOLIDIFIED MATERIAL USING THE SAME [0002]

The present invention relates to a method of solidifying sewage sludge and a solidified product using the same.

Domestic sewage sludge production is approaching 3.6 million tons per year as of 2014, and in the past, most of the throughput was dependent on simple landfill or marine dumping, which is a relatively simple and inexpensive method for treating such sewage sludge. However, as the marine dumping of sludge is totally prohibited in 2012, researches on sewage sludge resource conversion and disposal are being carried out in various ways, and local governments have adopted new treatment methods to treat existing marine dumping sludge It is true.

According to the Sewage Statistics of the Ministry of Environment in 2014, 55.7% of the sewage sludge was recycled, incineration was 22.3%, land reclamation was 18.9%, and drying was followed by 1.6%. In the case of recycling sewage sludge that is generated, it is evaluated to be the most desirable from the viewpoint of recycling industrial byproducts, but practically, sewage sludge is further processed in the sewage treatment plant in addition to the concentration, digestion and dehydration process Equipment is required.

Considering that local governments directly manage and operate the domestic sewage treatment plants, or that entrusted by the local governments are also responsible for the disposal of sewage sludge generated at the sewage treatment plant, the enormous financial burden accompanying the expansion of sewage sludge recycling It is inevitable that the effectiveness of sewage sludge fueling or fertilizing methods is limited by local governments.

In addition, when sewage sludge is buried or incinerated, there is room for civil complaints due to the odor generated in sewage sludge, and there is a preference for other disposal methods due to the negative recognition of environmental groups and local residents for landfill or incineration. This is not the case.

In order to solve such a problem, Korean Patent Registration No. 10-1735096 proposes a method for producing a solidified material capable of reducing the water content of sewage sludge. However, if the strength of the solidification product formed by solidifying the sewage sludge is not sufficiently high, there is a possibility that the leachate will be eluted, and a malodor can be generated from the solidification due to the bacteria present in the sewage sludge. Therefore, a new sewage sludge solidification treatment method This is urgent.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to provide a technique for recycling sewage sludge.

It is another object of the present invention to provide a technique for producing solidified materials having excellent strength and odor removed by recycling sewage sludge.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide an apparatus and method for controlling the same.

According to an aspect of the present invention, there is provided a method of solidifying sewage sludge, comprising: a sludge disinfection step of sterilizing sewage sludge with a microwave; A solidifying agent mixing step of adding a solidifying agent and a mixing water to the sludge sterilized in the sludge sterilization step; A solidifying agent mixing step of mixing the injected additives in the solidifying agent mixing step; And a curing step of curing the mixed mixture in the solidifying agent mixing step.

In addition, with respect to 100 parts by weight of the sludge sterilized in the sludge disinfection step, the solidifying agent injected in the solidifying agent mixing step is usually 5 to 50 parts by weight of Portland cement, 5 to 50 parts by weight of slag powder, and 5 to 50 parts by weight And the compounding number may be 5 to 30 parts by weight.

The solidifying agent is at least one selected from the group consisting of 10 to 30 parts by weight of fly ash, 1 to 20 parts by weight of red mud, 1 to 5 parts by weight of crude steel, 1 to 5 parts by weight of a reducing agent and 1 to 5 parts by weight of a pH reducing agent And may further include one.

In addition, in the sludge sterilization step, sewage sludge having a water content of 50 to 80% can be sterilized by microwave for 5 to 25 minutes.

Also, the desulfurized gypsum can be prepared as a soft material generated in a desulfurization process of a circulating fluidized bed boiler using petro coke as fuel.

In order to achieve this object, according to another aspect of the present invention, the solidified product prepared by the above-described method has a sedimentation ratio of not less than 2.5% measured by KS F 2320 and a maximum after compaction measured by KS F 2312 A dry density of 1.0 g / cm 3 or more, a uniaxial compressive strength measured according to KS F 2314 of 0.2 MPa or more, a pH measured according to KS F 2103 of 6.0 to 12.4, and KS F 2576 The water content measured according to KS F 2322 is in the range of 10 ^-7 cm / s to 10 ^-4 cm < ² > / s < / RTI >

The solution of the above-mentioned problems is merely illustrative and should not be construed as limiting the present invention. In addition to the exemplary embodiments described above, there may be additional embodiments described in the drawings and the detailed description of the invention.

As described above, the present invention has the following effects.

First, the method of solidifying sewage sludge according to the present invention is effective in sterilizing 99.9% of bacteria in sewage sludge by microwave sterilization.

Secondly, this sterilization process can optimize the solidification conditions of the high-function sludge to reduce the water content to less than 10%, to produce high-strength solidified soil with a strength of uniaxial compressive strength of 1.0 MPa or more, And odor generation can be suppressed.

Third, the solidification method of the sewage sludge according to the present invention satisfies all the certification items of the excellent recycled product quality certification standard (GR M 9020-2016) of the solid waste reclaimed sludge recovery sludge, And can contribute to environmental protection by presenting an environmentally friendly and economical sewage sludge treatment solution.

The effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the description of the claims.

FIG. 1 is a flowchart showing a method of solidifying sewage sludge according to an embodiment of the present invention.
Figure 2 is a flow chart detailing the solidifying agent mixing step according to one embodiment of the present invention.
3 is a conceptual view schematically showing a sludge mixing apparatus used in a solidifying agent mixing step according to an embodiment of the present invention.

The preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings, in which the technical parts already known will be omitted or compressed for simplicity of explanation.

A method for solidifying sewage sludge according to an embodiment of the present invention will be described with reference to the flowchart shown in FIG. 1 and will be described with reference to FIGS. 2 and 3 for convenience. .

1. Sludge disinfection step <S101>

In this step, a process of disinfecting the sewage sludge with a microwave may be performed. In one embodiment, the sewage sludge having a water content of 50 to 80% may be put into a microwave sterilization processor (not shown), and the microwave may be irradiated in the sterilization processor to sterilize the sewage sludge for 5 to 25 minutes. Here, the water content is a value representing a percentage of water contained in sewage sludge.

In this step, the oxygen atoms in water in the sewage sludge are rapidly rotated through the microwave disinfection process, and the kinetic energy is replaced with heat, thereby increasing the temperature of the sewage sludge.

That is, it is effective to sterilize 99.9% of the bacteria present in the sewage sludge by the microwave irradiated in this step and evaporate water in the sewage sludge to reduce the water content.

If the sterilization progress time is less than 5 minutes, the effect of reducing the water content of the sewage sludge and the sterilizing effect are decreased. If the sterilization progress time exceeds 25 minutes, the temperature of the sewage sludge excessively increases, It is preferable that microwave sterilization is performed within one hour.

On the other hand, at this stage, when sterilizing by a microwave sterilizer, the sterilization efficiency can be improved by stirring the sewage sludge with at least one impeller (not shown).

Since the bacteria present in the sewage sludge are removed through the microwave disinfection in this step, the solid matter produced in the solidifying agent mixing step and the solidifying agent mixing step after this step does not cause the bacterial propagation in the solid matter.

This step sterilizes germs present in the sewage sludge and reduces the water content of the sludge so that the strength of the final product through the solidifying agent mixing and curing steps is increased, And it is possible to suppress the generation of odor.

2. Solidifying agent mixing step < S102 >

In this step, the sludge sterilized in step S101 may be added to the sludge mixing device 10 together with the solidifying agent and the compounding water to form a blended product. In one embodiment, the solidifying agent and the compounding water can be blended in a certain amount with respect to 100 parts by weight of the sterilized sludge. Calcium oxide (CaO) contained in the solidifying agent reacts with water present in the sludge to produce calcium hydroxide (Ca (OH) ₂ ), so that the water content of the sludge can be reduced.

Specifically, the solidifying agent to be added in this step may include 5 to 50 parts by weight of ordinary Portland cement, 5 to 50 parts by weight of slag powder, and 5 to 50 parts by weight of desulfurization gypsum. The blended water may be added in an amount of 5 to 30 parts by weight based on 100 parts by weight of the sterilized sludge.

In one embodiment, the Portland cement is usually added to improve the strength of the solidifying agent, and may be included in an amount of 5 to 50 parts by weight based on 100 parts by weight of the sewage sludge subjected to the microwave disinfection process.

If the Portland cement is less than 5 parts by weight, it is difficult to expect the rigidity of the solidified product. When the amount exceeds 50 parts by weight, the effect of preventing the sludge sludge from becoming sludge is lowered and the economical efficiency is lowered. Or less.

In one embodiment, the slag powder refers to a fine powder obtained by pulverizing a blast furnace slag, which has been quenched by injecting water into a slag at a high temperature in a steel mill, at a mill to have a specific surface area of 6000 to 8000 cm2 / g.

The slag powder suppresses the release of heavy metals from the solidified material and reacts with the desulfurized gypsum to produce ettringite, thereby contributing to the improvement of the strength of the solidified material.

In one embodiment, the desulfurized gypsum is an industrial by-product resulting from the introduction of limestone for desulfurization in a furnace in a circulating fluidized bed boiler. Since the desulfurized gypsum is a soft material generated from the desulfurization process of a circulating fluidized bed boiler using petro coke as a fuel, the desulfurization gypsum contains a large amount of sulfur component contained in petro coke and calcium oxide (CaO) component in limestone.

As the desulfurized gypsum stimulates the slag powder to produce ettringite in the solidifying agent and exhibits potential hydraulic stability, the rigidity of the solidified material can be improved. Here, the slag powder and the desulfurized gypsum may be contained in an amount of 5 to 50 parts by weight with respect to 100 parts by weight of the sewage sludge subjected to the microwave disinfection process.

If the amount of each of the slag powder and the desulfurized gypsum is less than 5 parts by weight, it is difficult to expect the strength of the formed solidified material. If the amount of the solidifying agent is more than 50 parts by weight, the amount of the solidifying agent is increased compared to the sewage sludge, Since it is difficult to sufficiently supply water in the sewage sludge, there is a possibility that the workability is lowered.

On the other hand, since sewage sludge generated from municipalities has different constituents and physical properties depending on the characteristics of the area, it is selected from the group consisting of fly ash, red mud, coarse material, water reducing material and pH reducing agent It is preferable to mix at least one of them or a mixture of two or more thereof according to the characteristics of the sewage sludge.

That is, in one embodiment, the solidifying agent is 10 to 30 parts by weight of fly ash, 1 to 20 parts by weight of red mud, 1 to 5 parts by weight of crude steel, 1 to 5 parts by weight of a reducing agent, And 1 to 5 parts by weight of a reducing agent.

In one embodiment, fly ash is a fly ash produced by burning bituminous coal in a thermal power plant. Fly ash, a bituminous coal fly ash, contains a large amount of pozzolanic compounds such as silicon dioxide (SiO ₂ ) and aluminum oxide (Al ₂ O ₃ ).

These pozzolanic components cause a pozzolanic reaction with calcium hydroxide to produce calcium silicate hydrate and calcium aluminate hydrate, and as the solidification reaction takes place, it contributes to the improvement of the strength and water tightness of the solidifying agent.

In one embodiment, when the fly ash is added in an amount of less than 10 parts by weight based on 100 parts by weight of the sewage sludge subjected to the microwave disinfection process, it is difficult to expect the effect of improving the long-term strength and improving the water tightness. If the fly ash is more than 30 parts by weight, The degree of improvement is not so large as the amount of the added amount, and the efficiency may be lowered.

In one embodiment, Red Mud refers to the sludge remaining after extracting aluminum hydroxide (Al (OH) ₃ ) from the bauxite raw mineral through the Bayer process, an aluminum manufacturing process.

Red mud is strongly alkaline because it uses sodium hydroxide (NaOH) in the aluminum refining process and can contain silicon dioxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ) and iron oxide (Fe ₂ O ₃ ) have. Red mud makes regular portland cement strong alkaline in solidifying agent, induces dissolution reaction, and contributes to increase hydraulic speed and increase strength of cement.

In one embodiment, when Red Mud is added in an amount of less than 1 part by weight based on 100 parts by weight of sewage sludge subjected to a microwave disinfection process, it is difficult to expect an economical effect. If the amount exceeds 20 parts by weight, water content of the sewage sludge is inhibited It is preferable to apply it within the above-mentioned range.

In one embodiment, the crude steel is a strength enhancing agent for increasing the early strength of the cement, and is not particularly limited as long as it is added for the purpose of enhancing the strength of the cement. For example, the crude steel may be calcium acetate, calcium formate, calcium nitrate, sulfate compounds or the like.

In one embodiment, when the crude steel is charged in an amount of less than 1 part by weight based on 100 parts by weight of the sewage sludge subjected to the microwave disinfection process, the early strength of the cement may be lowered. If the amount is more than 5 parts by weight, The degree of improvement of the effect is insignificant, and the economical efficiency may be lowered due to an increase in the manufacturing unit cost, so that it is preferable to be charged within the above-mentioned range.

In one embodiment, the water reducing material acts as a cement dispersing agent for dispersing the powder of cement, and is an admixture aiming at improving the workability of the cement. The water reducing material can reduce the unit quantity for obtaining the workability of the cement, and it improves the strength and helps to save cement.

The water reducing material usable may be any one selected from the group consisting of naphthalene, melamine, lignin and polycarboxylic acid, or a mixture of two or more thereof. However, other known water reducing materials may be used.

In addition, when the water reducing material is added to less than 1 part by weight with respect to 100 parts by weight of the sewage sludge which has undergone the microwave disinfection process in one embodiment, the effect of water reducing is lowered and the strength of the solidifying agent may be lowered. It is preferable that the degree of improvement of the reduction effect with respect to the input amount is insignificant and the production unit cost may be increased, so that it is preferably carried out within the above-mentioned range.

In one embodiment, the pH reducing material reduces the pH of the sludge, thereby preventing the generation of odor and the elution of heavy metals. The kind of the pH reducing agent is not particularly limited as long as it is added for the purpose of reducing the pH of the sludge, and a conventionally known kind can be used. For example, a strong acid such as sulfuric acid, nitric acid, hydrochloric acid, or a mixture of different strong acids can be used as a pH reducing agent.

Further, in one embodiment, when the pH reducing agent is added in an amount of less than 1 part by weight based on 100 parts by weight of the sewage sludge subjected to the microwave disinfection process, it is difficult to expect a pH reduction effect. When the amount is more than 5 parts by weight, The degree of improvement of the contrast reduction effect is insignificant, so that it is preferable to be carried out within the above-mentioned range.

In one embodiment, the compounding number can usually be added to activate the solidifying agent components such as Portland cement, slag powder, desulfurized gypsum, fly ash, red mud, and the like.

That is, since the water required for the solidifying agent reaction is physically difficult to be completely covered with only water in the sludge, the compounding water may be added to improve workability.

If the blend amount is less than 5 parts by weight based on 100 parts by weight of the sewage sludge subjected to the microwave disinfection process, the effect of activating the portland cement, slag powder, desulfurization gypsum, fly ash and red mud is insignificant, The moisture content in the solidified material may be increased and the curing time may be prolonged, so that it is preferable to apply it within the above-mentioned range.

3. Solidifying agent mixing step < S103 >

In this step, the process of mixing the injected ingredients in step S102 may be performed. The solidifying agent mixing step according to one embodiment may include a stirring step, a concentration measuring step, a viscosity measuring step, a mixing degree judging step, and a discharging step.

The sludge mixing apparatus 10 according to an embodiment of the present invention may include a mixing chamber 100 and a control unit 200. The mixing chamber 100 may include a stirring impeller The ultrasonic measurement sensors 180 and 195 and the discharge port 197 may be provided on the upper and lower surfaces of the body 110. The ultrasonic measurement sensors 110 and 120 and the driving motors 140 and 150 may be used.

The stirring impellers 110, 120, and 130 are located in the mixing chamber 100 and may be rotated in one direction to mix the blended mixture into the mixing chamber 100. The stirring impellers 110, 120, and 130 can be changed in form or quantity according to the size of the mixing chamber 100.

In addition, the impeller blades 111, 121 and 131 may be spirally arranged along the longitudinal direction of the stirring impellers 110, 120 and 130 on the outer circumferential surfaces of the stirring impellers 110, 120 and 130. At this time, it is preferable that the direction of the optional impeller blades 111 is arranged to be shifted from the direction of the impeller blades 121 formed on the adjacent impeller 120 for stirring, from the viewpoint of stirring efficiency.

The driving motors 140, 150 and 160 are connected to one ends of the stirring impellers 110, 120 and 130 to provide power for rotating the stirring impellers 110, 120 and 130 in one direction. The plurality of stirring motors 140,150 and 160 may be provided in a number corresponding to the number of the stirring impellers 110,120 and 130 when the number of stirring impellers 110,120 and 130 provided in the mixing chamber 100 is plural. .

Load sensors 141, 151 and 161 are provided on one side of the drive motors 140, 150 and 160 to measure the load on the drive motors 140, 150 and 160 in real time and transmit measurement information to the controller 200 . For example, the load measuring sensors 141, 151, and 161 may generate measurement information by measuring a torque or a current value generated when the drive motors 140, 150, and 160 operate.

The control unit 200 can measure the viscosity of the mixture by comparing the viscosity measurement information stored in the controller 200 with the load measurement value. In addition, the controller 200 compares the plurality of measured values received from the load measuring sensors 141, 151, and 161 and determines that the mixture is uniformly mixed when the deviation between the measured values is within the reference range, The operation can be controlled.

At least one sensor capable of measuring the concentration of the mixture may be installed in the mixing chamber 100. In one embodiment, the infrared measurement sensors 170 and 190 and the ultrasonic measurement sensors 180 and 195 may be installed on the inner wall of the mixing chamber 100.

The infrared ray measurement sensor 170 may include an infrared ray transmitter 171 for transmitting infrared ray in the mixture direction and an infrared ray receiver 172 for receiving the transmitted infrared ray. The infrared rays emitted through the infrared ray transmitter 171 may be reflected on the water surface of the mixture or may be reflected on the sludge particles in the mixture.

That is, the infrared ray measuring sensor 170 measures the amount of light incident on the infrared ray receiver 172, and can measure the concentration of the mixture through the previously stored concentration information on the amount of the light ray. The infrared ray measurement sensors 170 and 190 may transmit the measured sludge concentration values to the control unit 200.

In one embodiment, the infrared measurement sensors 170 and 190 may be applied in a plurality of different locations within the mixing chamber 100. At this time, the controller 200 compares the concentration values received from the infrared measurement sensors 170 and 190 existing at different positions, and determines that the mixture degree of the mixture is good when the deviation of the concentration value is within the previously stored reference range can do.

The ultrasonic measurement sensor 180 may include an ultrasonic transmitter 181 for transmitting ultrasonic waves in the mixing direction and an ultrasonic receiver 182 for receiving the ultrasonic waves transmitted. It is possible to measure the concentration of the mixture on the basis of the propagation speed of the ultrasonic wave reaching the ultrasonic receiver 182 since the propagation speed of the ultrasonic wave transmitted from the ultrasonic transmitter 181 varies according to the concentration of the mixture.

That is, the ultrasonic measurement sensor 180 measures the propagation speed of the ultrasonic wave that has reached the ultrasonic receiver 182, compares the measured value with the density information of the ultrasonic wave propagation velocity previously stored in the ultrasonic measurement sensor 180, Can be measured. The ultrasound measurement sensors 180 and 195 may transmit the measured concentration values to the control unit 200.

In one embodiment, the ultrasonic measurement sensors 180 and 195 may be applied in a plurality of different locations within the mixing chamber 100. At this time, the control unit 200 compares the concentration values received from the ultrasonic measurement sensors 180 and 195 existing at different positions, and determines that the mixing degree of the mixture is good when the deviation of the concentration value is within the previously stored reference range can do.

The control unit 200 can control the operation of the driving motors 140, 150 and 160 and the opening and closing of the discharge port 197. In one embodiment, the control unit 200 receives concentration values of the mixture from the infrared measurement sensors 170 and 190 and the ultrasonic measurement sensors 180 and 195 and receives the concentration values of the mixture from the load measurement sensors 141, The concentration difference between the plurality of infrared measurement sensors 170 and 190 and the concentration difference between the plurality of the ultrasonic measurement sensors 180 and 195 and the concentration between the infrared measurement sensors 170 and 190 and the ultrasonic measurement sensors 180 and 195 It is possible to judge the degree of mixture of the mixture and to control the opening and closing of the discharge port 197 considering the deviation and the load deviation between the plurality of load measurement sensors 141, 151 and 161 comprehensively.

For example, when the deviation of the measured values transmitted from the sensors is within a certain range based on the mixed degree information of the sludge mixture stored in the controller 200, the controller 200 determines that the mixed degree of the mixture is good, And the discharge port 197 is opened to control the mixture to be discharged to the outside.

Since the infrared measurement sensors 170 and 190 may cause measurement deviations depending on the color of the surface of the mixture, the ultrasound measurement sensors 180 and 195 having different measurement methods may be used in parallel with the infrared measurement sensors 170 and 190, By measuring the concentration, it is possible to minimize the error that may occur between the concentration measurements and prevent the stirring time of the mixture from becoming unnecessarily long.

In addition, the control unit 200 comprehensively considers the measurement values received from different measurement sensors (for example, a load measurement sensor, an infrared measurement sensor, and an ultrasonic measurement sensor) to determine the mixture level of the mixture, Mixing is possible, which can contribute to the improvement of the quality of the solidified product.

3-1. Stirring step < S1031 >

In this step, blending of the blend can be facilitated through stirring by the stirring impellers 110, 120, and 130 in the mixing chamber 100 of the sludge blending device 10.

3-2. Concentration measurement step < S1032 >

In this step, a process of measuring the concentration of the mixed mixture in step S1031 may be performed. The concentration of the mixture may be measured through the infrared measurement sensors 170 and 190 and the ultrasonic measurement sensors 180 and 195 positioned in the mixing chamber 100 and the measured concentration value may be transmitted to the controller 200 .

3-3. Viscosity measurement step < S1033 >

In this step, the load measuring sensors 141, 151, and 161 measure the load values of the driving motors 140, 150 and 160 for rotating the stirring impellers 110, 120 and 130, and transmit the measured load values to the controller 200 . In addition, this step can be performed simultaneously with step S1032.

3-4. In the mixing degree determination step < S1034 >

In this step, the controller 200 may determine the mixture degree of the mixture in the mixing chamber 100. That is, the controller 200 determines whether or not the mixture is uniformly mixed. If it is determined that the mixture is uniformly mixed, the control unit 200 controls the discharge port 197 to control the discharge step to proceed, and if it is determined that the mixture is not uniform , The control returns to step S1031 so that the stirring by the stirring impellers 110, 120, and 130 can be controlled again.

In this step, the controller 200 considers the measurement values received from the different types of measurement sensors in a comprehensive manner to determine the degree of mixture of the mixture, so that the mixture can be uniformly mixed. For example, when it is determined that the received concentration value and the load value are within the range of the reference value previously stored in the controller 200, the controller 200 determines that the mixture level of the mixture is good, can do.

3-5. Discharging Step < S1035 >

In this step, the discharge port 197 is opened by the control unit 200 to discharge the mixture located in the mixing chamber 100 to the outside.

4. Curing step < S104 >

In this step, the process of curing the discharged mixture in step S1035 may be performed. In one embodiment, curing is carried out at room temperature, but it is also possible to cure by heating at a certain temperature.

Hereinafter, the present invention will be described in more detail with reference to specific examples. The following examples are merely illustrative examples for the understanding of the present invention, and thus the scope of the present invention is not limited thereto or limited thereto.

The method for solidifying sewage sludge according to an embodiment of the present invention is for solidifying sewage sludge to recycle industrial by-products as a new use. As a related standard, there is GR (Good Recycled) certification standard of "high-cargo for recovery of waste rocks" according to Notification No. 2009-125 of KSATS.

In order to recycle the solidified sewage sludge, it is required to satisfy the above-mentioned GR certification standard. Therefore, the performance of the solidified soil prepared according to the embodiments of the present invention is compared with the GR certification standard.

&Lt; Example 1 >

First, the microwave disinfection process was performed for 15 minutes on sewage sludge having a water content of 80%, and then 26 parts by weight of ordinary portland cement, 37 parts by weight of slag powder, 35 parts by weight of desulfurized gypsum, ) And 20 parts by weight of the compounding water were mixed to solidify the sewage sludge, place it in a 10? X20 cm mold, and then cure at room temperature for 28 days.

&Lt; Example 2 >

First, the microwave sterilization process was performed on the sewage sludge having a water content of 80% for 15 minutes. Then, 26 parts by weight of ordinary Portland cement, 37 parts by weight of slag powder, 27 parts by weight of desulfurized gypsum, 10 parts by weight of Red mud And 20 parts by weight of the compounding water were mixed to solidify the sewage sludge, place it in a 10? X20 cm mold, and then cure at room temperature for 28 days.

&Lt; Example 3 >

First, the microwave sterilization process was performed on the sewage sludge having a water content of 80% for 15 minutes. Then, 26 parts by weight of ordinary Portland cement, 37 parts by weight of slag powder, 27 parts by weight of desulfurized gypsum, 10 parts by weight of Red mud 20 parts by weight of fly ash, 2 parts by weight of crude steel, 2 parts by weight of water reducing agent, 2 parts by weight of pH reducing agent and 20 parts by weight of compounding water were mixed to solidify sewage sludge, Lt; / RTI &gt;

&Lt; Comparative Example 1 &

3 parts by weight of ordinary Portland cement, 3 parts by weight of slag powder, 3 parts by weight of desulfurized gypsum, 0.5 parts by weight of Red mud, 0.5 parts by weight of a red mud, 100 parts by weight of a sterilized sludge, 8 parts by weight of fly ash, 0.5 part by weight of crude steel, 0.5 part by weight of a reducing agent, 0.5 part by weight of a pH reducing agent and 3 parts by weight of a compounding water were mixed to solidify the sewage sludge, Lt; / RTI &gt;

&Lt; Comparative Example 2 &

First, the microwave sterilization process was performed on the sewage sludge having a moisture content of 80% for 15 minutes. Then, 52 parts by weight of ordinary portland cement, 52 parts by weight of slag powder, 52 parts by weight of desulfurized gypsum, 22 parts by weight of red mud 22 32 parts by weight of fly ash, 7 parts by weight of crude steel, 7 parts by weight of reducing agent, 7 parts by weight of pH reducing agent and 32 parts by weight of compounding water were mixed to solidify the sewage sludge, Lt; / RTI &gt;

<Performance Test Methods and Results>

A microwave sterilization process was carried out for sewage sludge with a water content of 80% for 15 minutes and the amount of bacterial change in sterilized sludge was measured and submitted to the Korea Chemical Fusion Research Institute. The results are shown in Table 1 below.

Test Items unit Sample classification Results Test Methods Common bacteria CFU / g Sample A - Before sterilization 4.4 x 10 ⁵ Eating water quality process test basis: 2015 Common bacteria CFU / g Sample B - after sterilization 4.1 x 10 ²

As shown in Table 1, the microwave sterilization process was carried out for 15 minutes, and the bacteria in the sewage sludge were found to be reduced by 99.9%.

The solidified soil properties of Examples 1 to 3 and Comparative Examples 1 and 2 were measured according to the test method specified in the GR certification standard, and detailed test methods and results are as shown in Table 2 below.

Test Items unit GR Certification Criteria Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Test Methods Modified CBR (ratio of bearing capacity of subgrade) % 2.5 or more 20.3 20.5 25 1.1 2.1 KS F 2320 Maximum dry density after compaction g / cm3 1.0 or higher 1.5 1.6 2.0 0.5 0.7 KS F 2312 Uniaxial compressive strength MPa 0.2 or more 1.80 1.92 3.0 0.1 0.1 KS F 2314 pH - 6.0 - 12.4 12.2 12.4 10.0 13 13 KS F 2103 Organic matter content volume% 1.0 or less 0.0 0.0 0.0 2.0 2.1 KS F 2576 Function cost % Less than 50 3.7 3.4 2 4 4 KS F 2306 Permeability coefficient cm / s 10 ^-7 to 10 ^-4 1.3x10 ^-5 1.5x10 ^-5 1.0 x 10 ^-5 1.7 x 10 ^-5 1.2 x 10 ^-5 KS F 2322 Harmful heavy metals mg / l Below standard Below standard Below standard Below standard Below standard Below standard The "Soil Pollution Process Test Standard" specified in Article 6 of the "Act on Environmental Testing and Inspection, etc."

As can be seen from Table 2, the solidified soot, which is solidified through the solidification method of the sewage sludge according to an embodiment of the present invention, satisfies the maximum dry density, pH, permeability coefficient and harmful heavy metal standard value after compaction , Especially in the case of modified CBR, uniaxial compressive strength, organic matter content and water content.

The microbial sterilization process removes germs from sewage sludge and inhibits the inhibition of etring zite formation and potential hydraulicity. Also, the solidifying agent added with the sludge can improve the solidification effect of sewage sludge Is increased.

For reference, the modified CBR, which is one of the test items in Table 2, is the ratio of the bearing capacity of the subsoil to the strength of the bedrock material that can be expected in the field. The test load strength according to the amount of penetration is divided by the standard load strength according to the amount of penetration, . Since the modified CBR is measured according to KS F 2320, detailed description is omitted.

Conventionally, a solidification method has been popular as a method for treating a sewage sludge having a high water content. However, since the water and organic matter content in the sewage sludge is high, it is difficult to solidify the solidification treatment. The organic matter in the sewage sludge interferes with the solidification process and the solidified material does not have sufficient rigidity. Therefore, when used as a landfill material or a cover material, it may cause a lot of environmental problems such as leakage of leachate and generation of odor.

In order to control the water content and odor in the solidification of a large amount of sewage sludge, there is a problem that the price of the solidifying agent is rapidly increased due to the use of a deodorant and the like. However, the method of solidifying sewage sludge according to the present invention, It is effective to sterilize bacteria in the sewage sludge by 99.9%.

In addition, the present invention is capable of producing a high strength solidified soil having a strength of 1.0 MPa or more with uniaxial compressive strength lowering the water content to 10% or less by optimizing the solidification condition of the high function sludge through the microwave sterilization process, And the generation of odor can be suppressed.

In addition, the solidification method of the sewage sludge according to the present invention satisfies all certification items of the excellent recycled product quality certification standard (GR M 9020-2016) of the solid waste reclaimed sludge recovery slurry, And can contribute to environmental protection by presenting an environmentally friendly and economical sewage sludge treatment solution.

Industrial byproducts such as fly ash, desulfurization gypsum and red mud can be recycled to solidified soil to reduce waste treatment costs and prevent environmental pollution caused by waste.

Typically, sewage sludge is different from conventional cements, solidifying agents and other mixtures in that mixing requires differentiation due to their physical properties. That is, since the coagulant component contained in the sewage sludge acts as a factor that interferes with the mixing of the sewage sludge and the solidifying agent, when the general mixing method is used, the sewage sludge can not be mixed with the solidifying agent evenly, Lt; RTI ID = 0.0 &gt; strength. &Lt; / RTI &gt;

However, in the present invention, the mixture may be agitated until the mixture containing the sterilized sludge, the solidifying agent and the compounding water is uniformly mixed by measuring the degree of mixture of the mixture by the sensor and determining whether or not to re-stir according to the measurement result. That is, as the high mixing degree of the mixture directly contributes to the strength of the solidified product, the quality of the solidified product is improved.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. And the scope of the present invention should be understood as the scope of the following claims and their equivalents.

10: sludge mixing device
100: mixing chamber
110, 120, 130: stirring impeller
111, 121, 131: Impeller blades
140, 150, 160: drive motor
141, 151, 161: load measuring sensor
170, 190: Infrared measurement sensor
171: Infrared transmitter
172: Infrared receiver
180, 195: Ultrasonic measurement sensor
181: Ultrasonic transmitter
182: Ultrasonic receiver
197: Outlet
200:

Claims (6)

A sludge sterilization step of sterilizing the sewage sludge with a microwave;
Adding a solidifying agent to the sludge sterilized in the sludge sterilization step and mixing water for activating the solidifying agent;
A solidifying agent mixing step of mixing the injected additives in the solidifying agent mixing step; And
And a curing step of curing the mixed mixture in the solidifying agent mixing step,
With respect to 100 parts by weight of sludge sterilized in the sludge sterilization step,
The solidifying agent to be added in the solidifying agent mixing step is usually 5 to 50 parts by weight of Portland cement, 5 to 50 parts by weight of slag powder, 5 to 50 parts by weight of desulfurizing gypsum, 10 to 30 parts by weight of fly ash, 1 to 20 parts by weight of red mud 1 to 5 parts by weight of a base material, 1 to 5 parts by weight of a reducing agent, and 1 to 5 parts by weight of a pH reducing agent. The blended water is added in an amount of 5 to 30 parts by weight,
In the sludge sterilization step, the sewage sludge having a water content of 50 to 80% is sterilized by microwave for 5 to 25 minutes
Method for solidification of sewage sludge. delete delete delete The method according to claim 1,
Wherein the desulfurized gypsum is a combustion material generated in a desulfurization process of a circulating fluidized bed boiler using petro coke as a fuel
Method for solidification of sewage sludge. A solidified product prepared by the process according to any one of claims 1 to 5,
And the maximum dry density after compaction measured according to KS F 2312 is 1.0 g / cm 3 or more and the uniaxial compressive strength measured according to KS F 2314 is 0.2 MPa or more, the pH measured according to KS F 2103 is 6.0 to 12.4, the organic foreign matter content measured according to KS F 2576 is 1.0 volume% or less, and the water content measured according to KS F 2306 is 50% or less, and the permeability coefficient measured according to KS F 2322 is 10 ^-7 cm / s or more to 10 ^-4 cm / s or less
High freight.

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