Construction sludge treatment device and construction sludge treatment method

Abstract

To provide a construction sludge treatment device capable of effectively utilizing raw materials by reducing an amount of a solidifying material and regenerating fluidized treated soil with desired characteristics, even when the raw materials are diversified, such as soil, mud, sludge, and muddy water.SOLUTION: A construction sludge treatment device includes: a soil receiving section A for receiving construction soil as a raw material; a sludge receiving section B for receiving construction sludge as a raw material; a crushing section C for crushing the received raw materials; a classification section D for separating a material to be treated after being crushed by the crushing section C into recycled sand and suspended water; a neutralization processing section E for adding a neutralizing agent to the suspended water separated by the classification section D to neutralize the suspended water; a settling and concentrating section F for adding a flocculant to the suspended water neutralized in the neutralization processing section E to flocculate a suspended matter in the suspended water to obtain concentrated suspended water; and a liquefied treated soil generating section H for adding a solidifying material to the suspended water concentrated in the settling and concentrating section F to generate slurry-like liquefied treated soil.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a construction sludge treatment device and a construction sludge treatment method for regenerating construction soil and construction sludge, which are industrial waste, into slurry-like fluidized treated soil that can be used as general-purpose sand, plastering sand, and other reclaimed sand and backfill material. [Background technology]

[0002] Conventionally, construction sludge, which is generated at construction sites and has a high moisture content, has been treated as industrial waste and mixed with cement and other materials at intermediate treatment plants to be used as liquefied treated soil for backfilling. Patent Document 1 is an example of a system that provides liquefied treated soil by collecting construction mud at a factory and processing it. Patent Document 1 discloses a technology in which large gravel and stone pieces are removed from the mud collected at the factory, the mud is stored at the factory in the form of a muddy liquid containing moisture or in the form of a dehydrated product after being dehydrated, and cement and other materials are mixed into the muddy liquid, the specific gravity of which has been adjusted according to the requirements of the site of use, to regenerate the soil into liquefied treated soil.

[0003] Furthermore, Patent Document 2 discloses a method for reusing and reducing the volume of construction generated soil and construction sludge by adding water to soil material consisting of construction generated soil and construction sludge to thaw the soil, and then supplying the thawed water from which gravel has been removed and cement milk to a truck mixer to mix and knead them together to produce fluidized treated soil.

[0004] Furthermore, Patent Document 3 discloses a simple method for supplying liquefied treated soil in which water is mixed with soil and sand to loosen the soil, and then relatively large foreign objects are removed using a vibrating sieve. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2006-051437 A [Patent Document 2] JP 2018-021378 A [Patent Document 3] Patent Publication No. 2021-070992 Summary of the Invention [Problem to be solved by the invention]

[0006] In the prior art of the above Patent Documents 1 to 3, the construction soil and construction sludge generated at construction sites varies greatly in properties, with a specific gravity of 1.1 to 1.4, a pH of 6 to 12, and a composition with a high sand content. Since the raw material is industrial waste sludge containing organic matter and cement-based substances, there are differences in the performance of the recycled liquefied treated soil, such as strength, fluidity, and separation resistance, and even if the amount of solidifying material such as cement added is adjusted, liquefied treated soil with the desired characteristics cannot be obtained in strength tests and separation tests after production, resulting in a problem of high waste.

[0007] Problems with the treatment process include the steps of receiving, classifying, storing, mixing, and shipping. Since the sand content varies during classification, there is a large difference in the sand concentration of the stored raw materials, which can easily lead to variations in the quality of the produced liquefied treated soil. Also, if the pH of the raw materials is high, scaling can form on the walls, mixing blades, and piping if the storage time during treatment is long, which can lead to clogging of the piping. This results in an increase in the amount of time production is down due to maintenance to remove the scaling.

[0008] Furthermore, if the concentration of the raw material muddy water is low, it is necessary to increase the amount of solidification material added. However, many of the solidification material components are cement-based, which has high CO2 emissions, which creates problems not only in terms of cost but also in terms of the environmental burden. As the demand for liquefied treated soil has increased in recent years, it has become important to find ways to turn a variety of raw materials (industrial waste sludge) into products that best meet the needs, and from the perspective of the SDGS (Sustainable Development Goals), there is a demand to reduce the amount of solidification material used while making effective use of raw materials.

[0009] Therefore, the object of the present invention is to provide a construction sludge treatment device and a construction sludge treatment method which can use the diversifying construction waste soil and construction sludge as raw materials, produce liquefied treated soil of the desired quality with a minimum amount of solidifying agent, and recover valuable sand. [Means for solving the problem]

[0010] The construction sludge treatment device of the present invention comprises: A construction sludge treatment device that regenerates construction soil (solid) and construction sludge (liquid) into regenerated sand and liquefied soil, a soil receiving section where construction soil is delivered; a sludge receiving section where construction sludge is carried in; A crushing unit that crushes the construction soil transported to the soil receiving unit and the construction sludge transported to the sludge receiving unit; A classification unit that separates the material to be treated after the crushing unit into recycled sand and suspended water; a neutralization processing unit that adds a neutralizing agent to the suspended water separated by the classification unit to neutralize the suspended water; a sedimentation and concentration section for adding a flocculant to the suspended water neutralized in the neutralization section to flocculate suspended matter in the suspended water and obtain a concentrated suspended water; and a fluidized treated soil production section that adds a solidification material to the suspended water concentrated in the sedimentation concentration section to produce a slurry-like fluidized treated soil.

[0011] In addition, the configuration of the construction sludge treatment device of the present invention is characterized in that the sludge receiving section includes a raw mud pit for storing the construction sludge, and a sand divider for separating the construction sludge into solids and suspended water, and the sand divider includes a vibrating sieve, a cyclone, and an adjustment tank.

[0012] The construction sludge treatment apparatus according to claim 1, wherein the crushing unit includes a ball mill.

[0013] The construction sludge treatment apparatus of the present invention is characterized in that the classifying section includes a spiral classifier, a vibrating sieve for draining, and a cyclone.

[0014] Moreover, the construction sludge treatment apparatus of the present invention is characterized in that the reclaimed sand has an average particle size of 0.74 mm to 2 mm.

[0015] The construction sludge treatment method of the present invention is a construction sludge treatment method for regenerating construction soil and construction sludge into sand and liquefied treated soil, a soil receiving process in which construction soil is delivered; a sludge receiving process in which construction sludge is transported; A crushing process for crushing the construction soil brought in at the soil receiving process and the construction sludge brought in at the sludge receiving process; A classification process for separating the material to be treated after being crushed in the crushing process into reclaimed sand and suspended water; a neutralization treatment step of adding a neutralizing agent to the suspended water separated in the classification step to neutralize the suspended water; a sedimentation and concentration step of adding a flocculant to the suspended water neutralized in the neutralization treatment step to flocculate suspended matters in the suspended water to obtain a concentrated suspended water; The method further comprises a liquefied treated soil production process in which a solidification material is added to the suspended water concentrated in the sedimentation concentration process to produce a slurry-like liquefied treated soil. Effect of the Invention

[0016] According to the present invention, by simultaneously treating construction soil and construction sludge, even if the raw materials contain a diverse range of soil, mud, sludge, muddy water, etc., the amount of solidifying agent can be reduced and the raw materials can be regenerated into sand with desired characteristics (general-purpose sand, plastering sand, etc.) and slurry-like fluidized treated soil that can be used as backfill material, etc., thereby making effective use of the raw materials.

[0017] Furthermore, according to the present invention, by providing a neutralization treatment section before the settling and thickening section, even if the received sludge contains a lot of calcium and has a high pH, ​​scaling is unlikely to occur on the walls, stirring blades, and piping, making it possible to shorten the time production is down for maintenance to remove the scaling and to prevent blockage of the piping. Furthermore, even if the pH varies due to differences in the calcium content of the received muddy water, it is possible to reduce fluctuations in the amount of solidifying agent added, preventing deterioration of the performance of the liquefied treated soil and stabilizing the performance of the liquefied treated soil. [Brief description of the drawings]

[0018] [Figure 1] 1 is a diagram showing the overall configuration of a construction sludge treatment apparatus according to one embodiment of the present invention. [Diagram 2] 2 is an enlarged view showing the configuration of the soil receiving section A. FIG. [Diagram 3] 4 is an enlarged view showing the configuration of the sludge receiving section B. FIG. [Figure 4] 13 is an enlarged view showing a configuration in which a ball mill 28 is used in the crushing section C. FIG. [Diagram 5] 4 is an enlarged view showing the configuration of a classifying section D. FIG. [Figure 6] 1 is an enlarged view showing the configuration of a neutralization processing unit E. FIG. [Figure 7] FIG. 13 is an enlarged view showing the configuration of a sedimentation thickening section F when a square thickener 57 is used as a sedimentation device for performing sedimentation and separation by adding a polymer flocculant. [Figure 8] 2 is an enlarged view showing the configuration of a slurry storage tank section G. FIG. [Figure 9] An enlarged view showing the configuration of the liquefied treated soil production section H. [Figure 10] FIG. 2 is an enlarged view showing the configuration of the dehydration section I. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0020] FIG. 1 is a diagram showing the overall configuration of a construction sludge treatment device 1 according to one embodiment of the present invention. The construction sludge treatment method will be described below assuming that the construction sludge treatment device 1 is used to perform the construction sludge treatment method. The construction sludge treatment device 1 according to the embodiment can be used to regenerate soil to be treated, including construction waste soil, dredged soil, muddy construction mud with high water content, construction sludge, and construction muddy water, generated by ground excavation in construction work, into sand (general-purpose sand, plastering sand, etc.) and liquefied treated soil. Sand (general-purpose sand, plastering sand, etc.) is used for construction materials, parks, etc. In addition, liquefied treated soil has fluidity and self-hardening properties, and is used for underground buried pipes, backfill soil for utility trenches, and filling cavities in building foundation ground. The construction sludge treatment device 1 includes a soil receiving section A, a sludge receiving section B, a crushing section C, a classification section D, a neutralization treatment section E, a sedimentation and concentration section F, a slurry storage tank section G, a liquefied treated soil generating section H, and a dewatering section I.

[0021] (Soil Receiving Section A) 2 is an enlarged view showing the configuration of the soil receiving section A. The soil receiving section A includes a soil pit 2A into which solid construction sludge such as soil is carried by a transport vehicle 10A such as a dump truck, a tilted sieve 3, a magnetic sieve 4, a transport conveyor 5, and a backhoe 7 equipped with a bucket that supplies the soil 6 to be treated in the soil pit 2A to the tilted sieve 3.

[0022] The soil 6 to be treated carried into the soil pit 2A by the transport vehicle 10A is supplied to the inclined sieve 3 by the backhoe 7. The inclined sieve 3 drops particles with an average particle size of 150 mm or less from the supplied soil 6 to be treated onto the transport conveyor 5, and discharges particles with an average particle size of more than 150 mm into the rubble pit 2B by the transfer means 8. In addition, gravel that remains on the sieve of the lower sieve of the vibrating sieve 13 is transferred from the sludge receiving section B by the transfer means 17 to the soil pit 2A. The particles that have passed through the inclined sieve 3 and the material to be treated transferred from the sludge receiving section are thrown into the material receiving section 29 of the crushing section C by the transfer conveyor 5. The transport conveyor 5 consists of a first conveyor 5A, a second conveyor 5B, and a third conveyor 5C, and a magnetic sieve 4 is placed above the third conveyor 5C on the downstream side in the transport direction to remove metals such as iron and nickel from the material to be treated.

[0023] (Sludge Receiving Section B) 3 is an enlarged view showing the configuration of the sludge receiving section B. The sludge receiving section B is equipped with a raw mud pit 11 for storing fluid construction sludge (fluid matter) and a sand divider 12 for separating the construction sludge into solids and suspended solids. The sand divider 12 is equipped with a vibrating sieve 13, a cyclone S1, and an adjustment tank 14.

[0024] Fluid construction sludge such as mud and muddy water is carried into the raw mud pit 11 by a transport vehicle 10B such as a lorry. The space inside the raw mud pit 11 is divided into a first raw mud pit tank 11A and a second raw mud pit tank 11B by a partition wall 11C. Construction sludge is carried into the first raw mud pit tank 11A from the transport vehicle 10B. Heavy solids such as sand and gravel of the construction sludge carried into the first raw mud pit tank 11A are allowed to settle, and liquids containing light solids flow over the partition wall 11C into the second raw mud pit tank 11B and are stored there. If the carried construction sludge does not contain heavy solids such as sand and gravel, the construction sludge can be directly poured into the second raw mud pit tank 11B. A turbulent sand pump P1 is disposed at the bottom of the first tank 11A of the raw mud pit, and a mixture of the construction sludge settled in the first tank 11A and water containing heavy solids such as sand and gravel is sucked up by the turbulent sand pump P1 and pumped through a pipe 15 connected to the discharge port of the turbulent sand pump P1 to the treated material receiving section 29 of the crushing section C. A discharge pump P2 is disposed at the bottom of the second tank 11B of the raw mud pit, and the liquid construction sludge at the bottom of the second tank 11B of the raw mud pit is transferred to the lower sieve of the vibrating sieve 13 of the sand divider 12 through a pipe 16 connected to the discharge port of the discharge pump P2.

[0025] The vibrating sieve 13 is a vibrating sieve consisting of two sieves, one above the other, with the upper sieve having a finer mesh than the lower sieve. The mesh size of the sieves is set to be in the range of 0.3 to 30 mm, with the upper sieve having a finer mesh than the lower sieve. For example, the upper sieve has a mesh size of 0.5 mm, and the lower sieve has a mesh size of 20 mm. The gravel on the sieve that has been sieved by the lower sieve of the vibrating sieve 13 is transferred to the soil pit 2A by the transfer means 17. The transfer means 17 may be, for example, a drop chute. A cyclone S1 is disposed above the vibrating sieve 13. The cyclone S1 has a supply port, a first outlet, and a second outlet. One end of a pipe 18 is connected to the supply port, a pipe 19 is connected to the first outlet, and a pipe 20 is connected to the second outlet.

[0026] The adjustment tank 14 of the sand divider 12 has a partition wall 21. The space in the adjustment tank 14 is divided into a settling chamber 22 and an agitation chamber 23 by the partition wall 21. The settling chamber 22 is supplied with fine particles separated by the cyclone S1 through a pipe 20 connected to the second outlet of the cyclone. A discharge pump P3 is disposed in the settling chamber 22. The other end of the pipe 18 is connected to the outlet of the discharge pump P3. The material to be treated in the lower layer of the settling chamber 22 sucked into the discharge pump P3 is led to the supply port of the cyclone S1 through the pipe 18, and the solids are separated according to weight. In the cyclone S1, the heavy solids are returned to the upper sieve of the vibrating sieve 13 through the pipe 19, and the light particles are supplied to the settling chamber 22 through the pipe 20. The suspended water containing the light solids from the settling chamber 22 flows over the partition wall 21 into the agitation chamber 23.

[0027] A stirring blade 24 is disposed in the mixing chamber 23. The stirring blade 24 is mounted on a rotating shaft 25 that is driven to rotate around a vertical axis by a motor M1, and stirs the material to be treated in the mixing chamber 23 so that it does not settle or accumulate. A discharge port is provided on the side wall of the mixing chamber 23, and one end of a pipe 26 is connected to the discharge port, and the other end of the pipe 26 is connected to the inlet of a discharge pump P4. One end of a pipe 27 is connected to the discharge port of the discharge pump P4, and the material to be treated is transferred through the pipe 27 and from the other end of the pipe 27 to the fluidization mixer tank 72 or the dewatered sludge tank 88. When the material is to be supplied to the fluidization mixer tank 72, dilution water is supplied to the mixing chamber 23 through a pipe 87B by a dilution pump P16, and the specific gravity is adjusted.

[0028] (Crushing part C) In the crushing section C, a crushing machine such as a ball mill, a rod mill, or a hammer mill can be used as a crushing machine. However, it is preferable to use a ball mill, which can obtain high-quality sand without excessive crushing and can achieve both mud crushing and sand classification. By using a ball mill, it is possible to crush the mud lumps while leaving the sand, and it is possible to maintain the properties of the muddy water containing the crushed solids and ensure the amount of sand recovered as a valuable resource. Below, an example of using a ball mill in the crushing section C will be described.

[0029] FIG. 4 is an enlarged view showing a configuration in which a ball mill 28 is used in the crushing section C. The ball mill 28 includes a workpiece receiving section 29, a ball mill main body 30, and a sieving means 31. A dedicated hopper-shaped feeder is used for the workpiece receiving section 29. The ball mill main body 30 is cylindrical and has a rotating drum in which a plurality of iron balls are accommodated. The sieving means 31 is provided in communication with the outlet of the ball mill main body 30 and is formed into a substantially truncated cone shape by a wire mesh. In this embodiment, it is preferable that the sieving means be a cylindrical body having a truncated cone shape with a diameter expanding toward the tip.

[0030] The material receiving section 29 of the crushing section C receives particles supplied from the soil receiving section A, water containing particles supplied from the sludge receiving section B through the pipe 15, and washing water, and supplies the mixture to the ball mill main body 30. The particles supplied from the soil receiving section A can be supplied from the soil receiving section A by a conveying means 9 such as a belt conveyor. The water containing particles supplied from the sludge receiving section B is supplied from the bottom of the raw mud pit second tank 11B of the sludge receiving section B through the pipe 15 installed from the sludge receiving section B by the agitation type sand pump P1. The washing water is sucked by the discharge pump P5 through the pipe 85 installed from the circulating water tank 84 and supplied to the material receiving section 29. The circulating water tank 84 is a storage tank for storing the circulating water circulating within the construction sludge treatment apparatus 1 of this embodiment, and as described later, the circulating water tank 84 is supplied with the overflow water of the rectangular thickener 57 in the settling and thickening section F and the filtrate of the filter press 76 in the dewatering section I. When the circulating water is insufficient, make-up water is added from outside.

[0031] The ball mill main body 30 contains a cylindrical rotating drum containing a plurality of iron balls, and the mixed material is crushed by the impact of the iron balls falling due to the rotation of the drum. For example, in a device with a rotating drum having a diameter of 2.1 m and a length of 3.3 m, 100 to 200 iron balls with a diameter of 10 cm are used. By using such a ball mill, the material received is stirred and crushed while being washed with washing water, so that a spherical weight having a smaller weight than that of a rod mill or a rod scrubber is used, and the raw material is not crushed too finely, and regenerated sand having an average particle size of 2 mm or less and highly useful as a wall material and fine aggregate for concrete mortar can be obtained. In addition, when the iron balls of the ball mill wear out, it is sufficient to replenish them with new iron balls, and compared to a rod mill or a rod scrubber, there is no need to take the trouble of replacing worn rods with new ones, making it easier to maintain.

[0032] The material to be treated, which is muddy water containing solids crushed in the ball mill main body 30, is discharged to the sieving means 31 provided in communication with the discharge port of the ball mill main body 30, and the uncrushed solids are separated by a cylindrical wire mesh (trommel) in the shape of a truncated cone, which expands in diameter toward the tip. The uncrushed solids are accumulated in the overtank 32. The mesh size of the wire mesh of the sieving means 31 can be determined according to the grain size of the recycled sand to be reused. For example, when a wire mesh with a mesh size of 5 mm is used, versatile sand of 5 mm or less can be obtained. The muddy water (material to be treated) containing the crushed solids that has passed through the mesh size of the wire mesh of the sieving means 31 is transferred to the classifying section D via the flow path 86.

[0033] (Classification Department D) Fig. 5 is an enlarged view showing the configuration of the classification unit D. In the classification unit D, the material crushed in the crushing unit C is separated into recycled sand and suspended water. The classification unit D is composed of a first classification unit D1, a second classification unit D2, and a raw water pit 37. The first classification unit D1 is composed of devices such as a spiral classifier 33 and a vibrating sieve for draining water 36. The second classification unit D2 is composed of a cyclone S2 and a vibrating sieve for draining water 46.

[0034] First, the first classifying section D1 will be described. The spiral classifier 33 is composed of a pit 34 and a screw conveyor 35 at the bottom of the spiral classifier. The material to be treated that has been crushed in the crushing section C is transferred to the pit 34 of the spiral classifier 33 through a flow path 86. It is preferable to provide the sieving means 31 of the ball mill 28 at a position higher than the pit 34 to allow the material to fall naturally. If the pit 34 is provided directly below the sieving means 31 of the ball mill 28 to allow the material to fall naturally, there is no need to provide the flow path 86. The crushed solid matter with a large particle size that has settled settles at the bottom of the pit 34, and the settled solid matter is transported to the vibrating screen 36 for draining by the screw conveyor 35. The suspended water containing the crushed solid matter with a small particle size that has not been transported by the screw conveyor 35 overflows from the pit 34 of the spiral classifier and flows into the raw water pit 37.

[0035] The vibrating sieve 36 for draining water is a vibrating sieve with a sieve opening of 1.0 mm, and the muddy water containing large-grained crushed solids transported by the screw conveyor 35 falls onto the sieve, while the coarse-grained recycled sand that does not pass through the sieve is collected in a sand yard 39 by a belt conveyor 38. The suspended water that passes through the sieve is transferred to a raw water pit 37.

[0036] Next, the second classification section D2 will be described. In the second classification section D2, finer sand than that obtained in the first classification section D1 is classified by a water-cutting vibrating sieve 46 equipped with a cyclone S2 on the top. The suspended water concentrated in the suspended water receiving pit 51A of the neutralization processing section E is supplied to the cyclone S2.

[0037] In cyclone S2, large particles are separated and collected by centrifugation from the suspended water transferred via pipe 49 from the suspended water receiving pit 51A of the neutralization treatment section E in the lower part of cyclone S2 and returned to the sieve of the water-cutting vibrating sieve 46 via pipe 44. The suspended water containing particles not collected by cyclone S2 overflows from the upper part of cyclone S2 and is discharged via pipe 45 disposed at the upper part of cyclone S2 into the suspended water receiving pit 51A of the neutralization treatment section E.

[0038] The suspended water supplied from cyclone S2 through pipe 44 to the draining vibrating sieve 46 is separated into recycled sand and suspended water by the draining vibrating sieve 46. In the draining vibrating sieve 46, washing water is supplied to wash the sand on the sieve, thereby producing higher quality recycled sand. The recycled sand separated by the draining vibrating sieve 46 is collected in a sand yard 48 by a belt conveyor 47. The suspended water that passes through the sieve meshes of the draining vibrating sieve 46 is transferred under gravity to the raw water pit 37.

[0039] The vibrating sieve 46 for draining of the second classifying section D2 can produce ultra-fine sand of 1.0 mm or less, and when the mesh size of the sieve is 0.8 mm, sand of 0.8 mm to 1.0 mm can be produced. Such ultra-fine sand can be used for plastering sand, etc.

[0040] The mesh size of the draining vibrating sieve 36 in the first classification section D1 is set to 1.0 mm, and fine SS particles and water are removed by a dewatering sieve to produce high-quality reclaimed sand. When a sieve with the above mesh size is used, the sand that does not pass through the sieve has an average particle size of 1 mm to 2 mm, and is highly versatile sand with excellent water drainage. In addition, the sand that is not captured by the draining vibrating sieve 36, separated by the cyclone S2, and captured by the draining vibrating sieve 46 has an average particle size of 0.8 mm to 1 mm, and can be used as plastering sand. By setting the mesh size of the draining vibrating sieve 36 to 1 mm and combining it with the cyclone S2 and the draining vibrating sieve 46, plastering sand with a fine average particle size can be obtained, and the reclaimed sand can be effectively used.

[0041] The raw water pit 37 is equipped with an agitator 40, and the suspended matter in the suspended water received from the pit 34 below the spiral classifier, the draining vibrating sieve 36, and the draining vibrating sieve 46 is agitated by the agitator 40 so as not to settle or accumulate. Any agitator can be used as the agitator 40 as long as it is capable of agitating the suspended matter in the suspended water in the raw water pit 37 so as not to settle or accumulate, but an agitator 40 in which a rotating shaft 42 provided with an agitator blade 41 is rotated by a motor M2 as shown in Fig. 5 is preferably used. The suspended water in the raw water pit 37 is transferred to the suspended water receiving pit 51A of the neutralization treatment section E via a pipe 43 provided in the discharge pump P6.

[0042] (Neutralization processing section E) The construction sludge and muddy water treated in this embodiment contain a large amount of cement components and therefore have a high pH value, and the wastewater generated during the treatment requires pH adjustment before being discharged, but if the pH value is high during the treatment process, the treated material will solidify and adhere to the equipment as scale, causing problems such as the need to stop the operation of the manufacturing equipment for maintenance. For this reason, in this embodiment, a neutralization treatment section E is provided after the classification section D.

[0043] 6 is an enlarged view showing the configuration of neutralization processing unit E. Neutralization processing unit E includes a dilute sulfuric acid tank 50 and a pH adjustment tank 51. pH adjustment tank 51 is partitioned by a partition wall 51C into a suspended water receiving pit 51A and an adjustment and mixing tank 51B.

[0044] Suspended water is supplied to the suspended water receiving pit 51A from the raw water pit 37 of the classification section D via pipe 43, and suspended water is transferred from the cyclone S2 of the second classification section D2 via pipe 45. By retaining suspended water in the suspended water receiving pit 51A, suspended matter with a high specific gravity settles to the bottom, and a difference in concentration of suspended water occurs between the top and bottom of the suspended water receiving pit 51A. The suspended water with a lower concentration of suspended matter at the top flows over the top end of the partition wall 51C and flows into the adjusted mixing tank 51B. A discharge pump P15 is disposed at the bottom of the suspended water receiving pit 51A, and a pipe 49 is connected to the discharge port of the discharge pump P15, so that suspended water with a higher concentration of suspended matter is supplied to the cyclone S2 of the second classification section D2.

[0045] Adjustment stirring tank 51B is equipped with an agitator 52 for agitating the suspended water in adjustment stirring tank 51B. Dilute sulfuric acid is sucked from dilute sulfuric acid tank 50 by metering pump P7 and injected into adjustment stirring tank 51B via pipe 53 in order to adjust the pH of the suspended water. Any agitator can be used as the agitator 52 as long as it is capable of agitating the suspended water in adjustment stirring tank 51B without causing the suspended matter to settle and accumulate. However, an agitator 52 in which a rotating shaft 55 provided with an agitator blade 54 is rotated by a motor M3 as shown in FIG. 6 is preferably used.

[0046] Although the pH can be adjusted by measuring the pH value in the adjustment stirring tank 51B, the pH can be adjusted more finely by measuring the flow rate and pH value of the inflowing suspended solids and performing feedforward control or feedback control. Also, by making the pH adjustment tank 51 large-capacity, it is possible to prevent product variation. The suspended solids pH-adjusted in the pH adjustment tank 51 are transferred from the pH adjustment tank 51 to the settling and thickening section F via pipe 56 by the discharge pump P8. Also, a portion of the pH-adjusted suspended solids may be transferred to the slurry storage tank 65 via pipe 56A branching off from pipe 56 in order to adjust the slurry concentration in the slurry storage tank.

[0047] Since the neutralization treatment unit E is provided after the classification unit D, solidification due to high pH of the suspended water is suppressed, and the production downtime for maintenance can be reduced. In addition, by storing a large amount of suspended water in the pH adjustment tank 51, the concentration of suspended matter in the suspended water is made uniform, and variation in product quality can be suppressed.

[0048] (Sedimentation and thickening section F) The sedimentation thickening section F is supplied with the suspended water whose pH has been adjusted in the neutralization treatment section E. The pH-adjusted suspended water is suspended water in which fine solids are dispersed, and a flocculant is added in the sedimentation thickening section F before it is sent to a sedimentation device, where the flocculated suspended matter in the water is allowed to settle by gravity and separated into settled sludge and supernatant water. As the sedimentation device, various thickeners such as a circular thickener or a square thickener can be used. The flocculant can be appropriately selected from inorganic flocculants, polymer flocculants, and the like.

[0049] FIG. 7 is an enlarged view showing the configuration of the settling thickening section F when a square thickener 57 is used as a settling separation device that performs settling separation by adding a polymer flocculant. The settling thickening section F includes a polymer dissolving tank 58 and a square thickener 57. The polymer dissolving tank 58 stores the polymer flocculant in an agitated state. The polymer flocculant is injected from the polymer dissolving tank 58 into a pipe 56 via a pipe 59 by a metering pump P9, mixed in the pipe 56 with the suspended water whose pH has been adjusted in the pH adjustment tank 51, and supplied to the square thickener 57. The square thickener 57 is a settling thickening tank equipped with a discharge screw 60 at the bottom. The suspended particles in the suspended water are flocculated by the polymer flocculant to become flocculants with a high settling velocity, which are sedimented, concentrated and separated by gravity, and are deposited as thickened sludge at the bottom of the square thickener 57. The thickened sludge is scraped up around the intake of the discharge pump P10 by the discharge screw 60 and transferred as thickened suspended water by the discharge pump P10 from a pipe 61 installed at the discharge outlet at the bottom of the rectangular thickener 57 to a slurry storage tank 65 described below. An overflow weir 62 is provided at the top of the rectangular thickener 57, and clarified water overflows and is supplied to a circulating water tank 84 via a water passage 63.

[0050] (Slurry storage tank G) FIG. 8 is an enlarged view showing the configuration of the slurry storage tank section G. The slurry storage tank section G includes a slurry storage tank 65 having an agitator 64. The concentrated sludge that has been separated by settling in the square thickener 57 is supplied to the slurry storage tank 65 through a pipe 61. In addition, a part of the suspension water that has been adjusted in pH to adjust the concentration of the slurry may be supplied through a pipe 56A. The concentrated sludge is agitated by an agitator 64 so that the concentrated sludge does not settle and accumulate, and the concentrated sludge is kept in a uniform state and stored in the tank. The agitator 64 may be any agitator that can agitate the concentrated sludge so that it does not settle and accumulate, but as shown in FIG. 8, an agitator 64 in which a rotating shaft 67 provided with an agitator blade 66 is rotated by a motor M4 is preferably used. The concentrated sludge in the slurry storage tank 65 is supplied to the liquefied soil production section H through a pipe 68 by a discharge pump P11, and is used for the production of liquefied soil. Excess thickened sludge that is not used to produce liquefied treated soil is transferred to the dewatered sludge tank via pipe 68A branching off from pipe 68. The slurry storage tank 65 is also equipped with an agitation pump P12 and pipe 69, which circulates and agitates the slurry to prevent adhesion and solidification inside the slurry storage tank.

[0051] (Fluidization Treated Soil Production Section H) FIG. 9 is an enlarged view showing the configuration of the fluidized soil production section H. The fluidized soil production section H includes a solidification material silo 70, a solidification material supply conveyor 71, a fluidization mixer tank 72, and a fluidized soil pit 73. The fluidization mixer tank 72 is a tank for producing fluidized soil. The concentrated sludge concentrated in the slurry storage tank 65, the sludge to be treated in the mixing chamber 23 of the sludge receiving section B, and the solidification material stored in the solidification material silo 70 are charged into the fluidization mixer tank 72. The solidification material may be cement, a cement-based solidification material, lime, or the like, but cement is usually used. The solidification material is transported from the solidification material silo 70 to the fluidization mixer tank 72 by a solidification material supply conveyor 71. The solidification material supply conveyor 71 may be any type of conveyor, but a screw conveyor that can easily adjust the input amount is preferably used. The concentrated sludge concentrated in the slurry storage tank 65 is supplied through a pipe 68 by a discharge pump P11, and the sludge to be treated in the mixing chamber 23 of the sludge receiving section B is supplied through a pipe 27 by a discharge pump P4. The concentrated sludge and the solidification material fed into the fluidization mixer tank 72 are mixed by a mixer 74 to produce a slurry-like fluidized treated soil. Although the mixer 74 may be only a mixer 74B, it is preferable to provide a small mixer 74A near the water surface where the solidification material is fed. The mixer 74A can mix the solidification material that was fed and remained on the surface of the muddy water into the muddy water. If it is necessary to adjust the concentration of the fluidized treated soil, the dilution pump P16 in the circulating water tank 84 can supply dilution water through a pipe 87A to the fluidized mixer tank 72 to adjust the concentration. The produced fluidized treated soil is transported through a pipe 75 to the fluidized treated soil pit 73 and stored. The transport is preferably carried out by placing the fluidization mixer tank 72 at a position higher than the fluidized soil pit 73 and allowing the fluidized soil to fall naturally.

[0052] (Dehydration part I) FIG. 10 is an enlarged view showing the configuration of the dewatering section I. The dewatering section I is composed of a dewatered sludge tank 88, a filter press 76, a filtration tank 77, a neutralization tank 78, and the like. In the dewatering section I, the thickened sludge transferred from the slurry storage tank 65 through the pipe 68 and the pipe 68A and the sludge transferred from the stirring chamber 23 of the sludge receiving section B through the pipe 27 are supplied to the dewatered sludge tank 88. In the dewatered sludge tank 88, stirring is performed by a stirring device 89 so that the sludge does not settle and accumulate, and the thickened sludge is kept in a uniform state and stored in the tank. The stirring device 89 may be any type of stirring device that can stir the thickened sludge so that it does not settle and accumulate, but the type of stirring device used in the slurry storage tank 65 is preferably used. The sludge in the dewatered sludge tank 88 is supplied to the filter press 76 through a pipe 90 equipped with a discharge pump P17, and separated into filtrate and dewatered cake. The filtrate is collected in filtration tank 77, from which a portion is returned by discharge pump P13 through pipe 79 to circulating water tank 84 for use in washing the ball mill 28, while the remainder is transferred through pipe 80 to neutralization tank 78. In neutralization tank 78, the pH is adjusted to 5.8 to 8.6, the discharge standard based on the Water Pollution Prevention Act, and then discharged through pipe 81 by discharge pump P14. The dehydrated cake is transported by discharge conveyors 82 and 83, stored, and then used as improved soil or disposed of.

[0053] As described above, an embodiment of the construction sludge treatment method can be implemented by the construction sludge treatment device 1. That is, the construction sludge treatment method according to this embodiment is a construction sludge treatment method for regenerating construction soil and construction sludge into reclaimed sand and fluidized treated soil, and includes a soil receiving step in which construction soil is carried to a soil receiving section A, a sludge receiving step in which construction sludge is carried to a sludge receiving section B, a crushing step in which the construction soil carried in the soil receiving step and the construction sludge carried in the sludge receiving step are crushed in a crushing section C, and a classification step in which the material to be treated after being crushed in the crushing step is separated into reclaimed sand and suspended water. the suspension water separated in the classification step, a neutralization step in a neutralization treatment section E of adding a neutralizing agent to the suspension water separated in the classification step to neutralize it, a sedimentation concentration step in a settling and thickening section F of adding a coagulant to the suspension water neutralized in the neutralization step to coagulate suspended matter in the suspension water to obtain concentrated suspension water, and a fluidized treated soil production step in a slurry storage tank section G, a fluidized treated soil production section H, and a dewatering section I of adding a solidification material to the suspension water concentrated in the settling and thickening step to produce a slurry-like fluidized treated soil.

[0054] According to the construction sludge treatment method of this embodiment, by providing a neutralization treatment section before the settling and thickening section, even if the received sludge contains a lot of calcium and has a high pH, ​​scaling is unlikely to occur on the walls, stirring blades, and piping, making it possible to shorten the production downtime due to maintenance to remove the scaling and to prevent blockage of the piping. Furthermore, even if there is a variation in pH due to differences in the calcium content of the received mud water, it is possible to reduce the variation in the amount of solidifying agent added, preventing deterioration of the performance of the liquefied soil and stabilizing the performance of the liquefied treated soil.

[0055] Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above-mentioned embodiments, and various modifications and improvements are possible within the scope of the gist of the present invention. It goes without saying that all or part of the components of each of the above-mentioned embodiments can be appropriately combined within the scope of not contradicting each other. [Industrial Applicability]

[0056] The construction sludge treatment device and construction sludge treatment method of the present invention can regenerate construction sludge and muddy water, which are industrial waste, into slurry-like fluidized treated soil and sand (general-purpose sand, plastering sand, etc.) that can be used as backfill material, etc. [Explanation of symbols]

[0057] A Soil Receiving Section B Sludge receiving section C Crushing section D Classification department D1 1st classification section D2 2nd classification section E Neutralization treatment section F. Sedimentation and thickening section G Slurry storage tank H. Fluidized soil production section I Dehydration section M1~M4 motors P1 Agitation type sand pump P2~P6, P8, P10~P15, P17 discharge pump P7, P9 metering pump P16 Dilution water pump S1, S2 Cyclone 1. Construction sludge treatment equipment 2A Dirt pit 2B Rubble Pit 3 Slanted sieve 4 magnetic sieve 5. Transport Conveyor 6. Treated soil 7. Backhoe 8, 9 Transport means 10A, 10B Transport vehicle 11 Raw Mud Pit 11A Raw Mud Pit No. 1 Tank 11B Raw mud pit No. 2 tank 11C Partition Wall 12 Sand Divider 13 Vibrating sieve 14 Adjustment tank 15, 16, 18, 19, 20 tubes 17 Means of transport 21 Partition Wall 22 Sedimentation chamber 23 Mixing chamber 24 Mixing blade 25 Rotational Axis 26, 27 tube 28 Ball Mill 29 Processing material receiving section 30 Ball mill body 31 Screening means 32 Over Tank 33 Spiral Classifier 34 Pit 35 Screw Conveyor 36 Vibrating sieve for draining water 37 Raw Water Pit 38 Conveyor Belt 39 Sand Yard 40 Mixing device 41 Mixing Blade 42 Rotation axis 43, 44, 45 tube 46 Vibrating sieve for draining 47 Conveyor Belt 48 Sand Yard 49 tube 50 Dilute sulfuric acid tank 51 PH adjustment tank 51A Suspended water receiving pit 51B Adjustment mixing tank 51C Partition wall 52 Mixing device 53 tube 54 Mixing Blade 55 Rotation axis 56, 59, 61 tube 57 Square thickener 58 Polymer dissolution tank 60 Discharge screw 62 Overflow Weir 63 Waterway 64 Mixing device 65 Slurry storage tank 66 Mixing Blade 67 Rotational Axis 68, 69 tube 70 Solidification material silo 71 Solidification material supply conveyor 72 Fluidizing mixer tank 73 Fluidized soil pit 74, 74A, 74B Stirring device 75 tube 76 Filter Press 77 Water Tank 78 Neutralization tank 79, 80, 81 tube 82, 83 Discharge conveyor 84 Circulating water tank 85 tube 86 Flow Path 87A, 87B pipe 88 Dewatered sludge tank 89 Mixing device 90 tubes

Claims

1. A construction sludge treatment device that regenerates construction soil and construction sludge into regenerated sand and liquefied treated soil, a soil receiving section where construction soil is delivered; a sludge receiving section where construction sludge is carried in; A crushing unit that crushes the construction soil transported to the soil receiving unit and the construction sludge transported to the sludge receiving unit; A classification unit that separates the material to be treated after the crushing unit into recycled sand and suspended water; a neutralization processing unit that adds a neutralizing agent to the suspended water separated by the classification unit to neutralize the suspended water; a sedimentation and concentration section for adding a flocculant to the suspended water neutralized in the neutralization section to flocculate suspended matter in the suspended water and obtain a concentrated suspended water; a liquefied treated soil production section that adds a solidification material to the suspended water concentrated in the sedimentation concentration section to produce a slurry-like liquefied treated soil.

2. The construction sludge treatment device according to claim 1, characterized in that the sludge receiving section includes a raw mud pit for storing the construction sludge, and a sand divider for separating the construction sludge into solids and suspended water, and the sand divider includes a vibrating sieve, a cyclone, and an adjustment tank.

3. The construction sludge treatment apparatus according to claim 1, wherein the crushing unit includes a ball mill.

4. 2. The construction sludge treatment apparatus according to claim 1, wherein the classifying section includes a spiral classifier, a vibrating sieve for draining, and a cyclone.

5. The construction sludge treatment device according to any one of claims 1 to 4, characterized in that the regenerated sand is sand particles having an average particle size of 0.74 mm to 2 mm.

6. A construction sludge treatment method for regenerating construction soil and construction sludge into regenerated sand and liquefied treated soil, comprising the steps of: a soil receiving process in which construction soil is delivered; a sludge receiving process in which construction sludge is transported; A crushing process for crushing the construction soil brought in at the soil receiving process and the construction sludge brought in at the sludge receiving process; A classification process for separating the material to be treated after being crushed in the crushing process into reclaimed sand and suspended water; a neutralization treatment step of adding a neutralizing agent to the suspended water separated in the classification step to neutralize the suspended water; a sedimentation and concentration step section for adding a flocculant to the suspended water neutralized in the neutralization treatment step to flocculate suspended matters in the suspended water and obtain a concentrated suspended water; a liquefied treated soil production process in which a solidification material is added to the suspended liquid concentrated in the sedimentation and concentration process to produce a slurry-like liquefied treated soil.

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