Construction method for curing sewage in sewage pond by on-site dry-method mixing and curing soil

Abstract

The invention relates to the technical field of solidification of sewage in sewage ponds, and discloses a construction method for solidifying sewage in sewage ponds by mixing solidified soil in a dry method on site, which comprises the following construction steps: 1) collecting engineering residue soil to form a soil body material; 2) placing a curing agent in the storage tank, wherein the curing agent comprises superfine slag powder, fly ash, waste gypsum, water glass, mountain flour slag and furnace slag; 3) adding the soil body material and a curing agent into a stirrer for stirring and mixing to form a powdery cured material; 4) scattering the curing material into the sewage pond, and reacting and combining the curing material with the sewage to form a solid landfill body; the construction method for curing the sewage of the sewage pond by mixing the cured soil through the on-site dry method, provided by the invention, has the following advantages that (1) construction wastes such as engineering residue soil are consumed; 2) the construction cost is reduced; (3) the landfill body is more compact, the impermeability is better, and harmful substances can be more effectively fixed and wrapped in the landfill body; and 4) the construction process is simple.

Description

Technical Field

[0001] This invention patent relates to the technical field of solidifying sewage in sewage ponds. Specifically, it relates to a construction method for solidifying sewage in sewage ponds by dry mixing solidified soil on-site. Background Art

[0002] When the sewage disposal facilities near factories or living areas in the suburbs are imperfect, a large amount of sewage is discharged into nearby low-lying pond areas. After years of discharge, relatively large-scale sewage ponds are gradually formed. The sewage in the sewage ponds contains various harmful substances, which not only cause direct harm to groundwater and soil, but also affect the entire ecological environment. Harmful substances such as organic matter, malodorous substances, acids, alkalis, and salts in the sewage ponds have seriously affected the surrounding air, groundwater, and soil.

[0003] Currently, in order to reduce the harm of sewage ponds, generally two methods are adopted to treat sewage ponds: 1) Collect the sewage and discharge it after specialized centralized anaerobic harmless treatment; 2) Use inorganic cementitious materials to solidify or harden the sewage in the sewage ponds to reduce the impact of harmful substances in the sewage on the environment.

[0004] In the prior art, due to the high cost of the first treatment method, therefore, the sewage treatment of most sewage ponds adopts the second method, that is, adding inorganic cementitious materials such as cement and lime into the sewage ponds for solidification.

[0005] The inorganic cementitious materials and sewage undergo physical and chemical reactions to generate a large amount of hydrated gels, minerals and other stone bodies, such as calcium silicate hydrate, calcium ferrite hydrate, calcium ferroaluminate hydrate, ettringite, calcium carbonate, calcium hydroxide, etc. The sewage is solidified in these stone bodies, and a large number of harmful substances are fixed in these stone bodies and cannot penetrate and migrate outward, thereby reducing its impact on the surrounding environment.

[0006] However, the second method for sewage has the following defects: 1) The material cost is relatively high. The sewage in the sewage ponds is entirely solidified by inorganic cementitious materials, which is equivalent to adding enough cement and lime materials into the water and relying on the sewage and cement and lime to form a viscous cement slurry, and finally the cement slurry solidifies and hardens to form a stone body; 2) The pores of the stone body formed after the inorganic cementitious materials such as cement and lime are mixed with sewage are relatively large, and the anti-permeability is poor. Although most of the harmful substances in the sewage are fixed in the stone body, because the anti-permeability of the stone body is poor, a small part of the harmful substances still gradually seep out from the stone body, thereby polluting the surrounding environment again. Summary of the Invention

[0007] The purpose of the present invention is to provide a construction method for solidifying sewage in sewage ponds by dry mixing solidified soil on-site, aiming to solve the problem of high construction cost in the solidification treatment of sewage in sewage ponds in the prior art.

[0008] The present invention is implemented as follows. A construction method for on-site dry mixing of solidified soil to solidify sewage in sewage ponds includes the following construction steps:

[0009] 1), Collect engineering muck, and sequentially crush and screen the engineering muck to form the required soil material;

[0010] 2), Arrange a storage tank at the construction site, and place the solidifying agent in the storage tank. The solidifying agent includes slag powder, fly ash, waste gypsum, water glass, stone powder slag, and furnace slag;

[0011] 3), According to the design ratio, add the soil material and the solidifying agent into a mixer and stir and mix them to form a powdery solidified material, and transport the solidified material to the periphery of the sewage pond for stacking;

[0012] 4), Spread the solidified material into the sewage pond. After the solidified material and the sewage are mixed for a set time, the solidified material reacts with the sewage to combine and form a solid landfill body.

[0013] Further, in the construction step 3), before transporting the solidified material to the periphery of the sewage pond for stacking, use a measuring instrument to determine the outer boundary of the sewage pond and the landfill area that needs to be landfilled in the sewage pond, and set markers at the outer boundary.

[0014] Further, in the construction step 3), remove the sundries outside the sewage pond to form a construction zone surrounding the sewage pond, and stack the solidified material on the construction zone.

[0015] Further, in the construction step 1), measure and process the water content of the collected engineering muck so that the water content of the engineering muck is between 15% and 25%.

[0016] Further, in the construction step 1), when the water content of the engineering muck is greater than 15% - 25%, spread it out to dry until the water content of the engineering muck is between 15% and 25%.

[0017] Further, in the construction step 1), place the engineering muck in a crushing bucket for crushing to form crushed material, and place the crushed material in a drum screen for rolling screening to form a soil material with a particle size less than 50mm.

[0018] Further, in the construction step 3), place the soil material in the mixer and stir it independently for a set time, and then sprinkle the solidifying agent into the mixer until the solidifying agent and the soil material are stirred and mixed to form the solidified material.

[0019] Further, in the construction step 4), from the outer periphery to the central position of the sewage pond, the sewage pond is divided into a plurality of annular zones, and the plurality of annular zones are arranged in a nested manner in sequence and cover the entire sewage pond;

[0020] In the construction step 4), along the direction from the outside to the inside of the sewage pond, the curing material is scattered into a single annular zone by an excavator. After the curing material scattered in the annular zone reacts with the sewage and combines into a fixed landfill body, the curing material is then scattered into the next annular zone.

[0021] Further, in the construction step 3), the mixer includes a horizontally arranged mixing drum, the mixing drum has a horizontally arranged mixing chamber, the mixing chamber has a horizontally arranged mixing shaft, and a plurality of radial shafts are provided on the outer periphery of the mixing shaft. Along the axial direction of the mixing shaft, the plurality of radial shafts are arranged in a staggered manner;

[0022] The inner ends of the radial shafts are butted on the mixing shaft, and spiral blades are provided on the mixing shaft. The spiral blades are arranged spirally along the circumference of the mixing shaft and are respectively butted and fixed to the outer ends of the plurality of radial shafts; the spiral blades have adjacent segments located between adjacent radial shafts, and a plurality of through holes are provided on the adjacent segments, and the plurality of through holes are arranged at intervals along the length direction of the adjacent segments;

[0023] In the construction step 3), after the soil material is placed in the mixing chamber, the mixing shaft rotates horizontally, driving the spiral blades to rotate synchronously. The spiral blades stir and mix the soil material and the curing agent to form a curing material; during the stirring and mixing process of the curing material, it synchronously passes through the through holes, is dispersed and then mixed again.

[0024] Further, in the construction step 3), two layers of air injection pipes are provided on the inner side wall of the mixing chamber. The air injection pipes are arranged in a circumferential manner around the mixing chamber, and the two layers of air injection pipes are arranged at intervals along the height direction of the mixing chamber. A plurality of air injection micropores are provided on the air injection pipes, and the plurality of paint spraying micropores are arranged at intervals along the circumferential direction and the circumferential direction of the air injection pipes;

[0025] In the construction step 3), during the process of the mixing shaft rotating to stir and mix the curing material, the two layers of air injection pipes spray high-pressure gas into the mixing chamber, and the air injection pressures of the two layers of air injection pipes are different and alternate. The high-pressure gas sprayed by the two layers of air injection pipes performs multi-directional pneumatic stirring on the curing material.

[0026] Compared with the prior art, the on-site dry mixing method for curing soil to cure sewage in a sewage pond provided by the present invention has the following advantages:

[0027] 1) Consumed construction waste such as engineering muck. The engineering muck used for mixing on-site is not limited to the soil near the sewage pond, and the engineering muck from surrounding construction sites can also be transported to the site for standby.

[0028] 2) Reduced construction costs. Compared with the traditional process of solidifying sewage entirely with inorganic cementitious materials, the proportion of geotechnical solidifying agent in the solidifying agent is relatively small, mostly being engineering muck, which greatly reduces the construction costs.

[0029] 3) Used solidifying materials to solidify sewage. The solidifying agent not only undergoes a hydration reaction with sewage, but also undergoes a secondary chemical reaction with some clay minerals in the soil material, generating a landfill body containing more hydrated gel minerals and crystal minerals. The solidified landfill body is more compact and has better impermeability, and can more effectively fix and encapsulate harmful substances inside the landfill body.

[0030] For the traditional inorganic cementitious material to solidify sewage, it only undergoes a hydration reaction with water, generating limited hydrated gel minerals and crystal minerals. The solidified stone body has defects such as many pores, poor impermeability, and easy leakage of sewage.

[0031] 4) The construction process is simple. Directly conduct dry mixing on-site to form solidifying materials, and then directly place the solidifying materials into the sewage in the sewage pond. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 is a schematic flow chart of the construction method for solidifying sewage in a sewage pond with on-site dry-mixed solidified soil provided by the present invention;

[0033] Figure 2 is a partial internal schematic diagram of the mixer provided by the present invention;

[0034] Figure 3 is a construction schematic diagram of the construction method for solidifying sewage in a sewage pond with on-site dry-mixed solidified soil provided by the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0035] In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0036] The implementation of the present invention will be described in detail below with specific embodiments.

[0037] In the drawings of this embodiment, the same or similar reference numerals correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", etc. indicating the orientation or positional relationship, they are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the terms describing the positional relationship in the drawings are only for illustrative purposes and cannot be construed as a limitation of this patent. For those of ordinary skill in the art, the specific meanings of the above terms can be understood according to specific circumstances.

[0038] Referring to Figures 1-3 as shown, it is a preferred embodiment provided by the present invention.

[0039] The on-site dry mixing method for solidifying the sewage in the sewage pond with solidified soil includes the following construction steps:

[0040] 1), Collect engineering muck, crush and screen the engineering muck in sequence to form the required soil material;

[0041] 2), Arrange a storage tank at the construction site, place the curing agent in the storage tank, and the curing agent includes slag powder, fly ash, waste gypsum, water glass, stone powder residue and furnace slag;

[0042] 3), According to the design ratio, add the soil material and the curing agent into a mixer and stir and mix them to form a powdery solidified material 401, and transport the solidified material 401 to the periphery of the sewage pond 400 for stacking;

[0043] 4), Sprinkle the solidified material 401 into the sewage pond 400. After the solidified material 401 is mixed with the sewage for a set time, the solidified material 401 reacts with the sewage to form a solid landfill body 402.

[0044] The above-provided on-site dry mixing method for solidifying the sewage in the sewage pond with solidified soil has the following advantages:

[0045] 1), It consumes construction waste such as engineering muck. The engineering muck used for mixing on-site is not limited to the soil near the sewage pond 400, and the engineering muck from surrounding construction sites can also be transported to the site for standby;

[0046] 2), It reduces the construction cost. Compared with the traditional process of solidifying sewage entirely with inorganic cementitious materials, the proportion of geotechnical curing agent in the curing agent is relatively small, and most of it is engineering muck, which greatly reduces the construction cost;

[0047] 3) Use the solidifying agent 401 to solidify the sewage. The solidifying agent not only undergoes a hydration reaction with the sewage, but also undergoes a secondary chemical reaction with some clay minerals in the soil material, generating a landfill body 402 containing more hydrated gel minerals and crystal minerals. The solidified landfill body 402 is denser and has better impermeability, and can more effectively fix and encapsulate harmful substances inside the landfill body 402;

[0048] Traditional inorganic cementitious materials solidify sewage and only undergo a hydration reaction with water, generating limited hydrated gel minerals and crystal minerals. The solidified stone body has defects such as many pores, poor impermeability, and easy leakage of sewage.

[0049] 4) The construction process is simple. The solidifying agent 401 is directly dry-mixed on-site, and it is only necessary to directly place the solidifying agent 401 into the sewage in the sewage pond 400.

[0050] In this embodiment, the solidification principle of the soil material is as follows:

[0051] Currently, the solidifying agent used for solidifying soil is composed of various industrial solid wastes and additives, such as slag powder, fly ash, waste gypsum, water glass, stone powder slag, slag and additives. The industrial solid wastes all contain minerals such as silicon, aluminum, and calcium with different degrees of activity. Under the excitation of additives, the mineral activity in various industrial solid wastes can be maximally excited to participate in chemical reactions.

[0052] When the proportions of various industrial solid wastes reach the optimal proportion, the active silicon, aluminum, calcium and other minerals in these industrial solid wastes can react with water and clay minerals to generate the most hydrated gel minerals and other crystal minerals.

[0053] Compared with traditional cement materials, the active minerals in industrial solid wastes and the minerals with excited activity not only react with water to generate hydrated gel minerals and other crystal minerals, but also further react with clay minerals in the soil to generate hydrated gel minerals and other crystal minerals.

[0054] Therefore, when the solidifying agent composed of industrial solid wastes is mixed with the soil material, more hydrated gel minerals and other crystal minerals can be generated. These hydrated gel minerals and crystal minerals grow in the soil material. On the one hand, they connect the soil material aggregates that have not participated in the chemical reaction, and on the other hand, they wrap the soil material aggregates, making the soil material strengthened by the solidifying agent have higher strength, impermeability, water stability and corrosion resistance.

[0055] In this embodiment, the specific dosage of the solidifying agent 401 is as follows:

[0056] According to a large number of experiments, the minimum density of the solidifying agent 401 after being added to the water body is generally 1.35t / m 3, that is, the density of the solidified material 401 after adding water is less than 1.35 t / m 3 , the solidified material 401 cannot solidify due to excessive water content, and its strength drops rapidly.

[0057] The weight of the sun-dried soil material required for each ton of sewage is calculated according to the following formula:

[0058]

[0059] The derivation process of this formula is as follows:

[0060]

[0061] m 固 ——The weight of the curing agent, in t; it can be calculated according to the following formula

[0062] m 固 =αm 湿

[0063] α——The weight ratio of the curing agent to the soil material, in %, generally 20 - 30%;

[0064] m 湿 ——The weight of the soil material simply treated on-site, in t;

[0065] m 污 ——The weight of the sewage to be treated, in t;

[0066] The weight of the soil material is calculated according to the following formula, m 湿 =m 干 +m 水

[0067] m 干 ——The weight of the dry soil without water in the soil material, in t;

[0068] m 水 ——The weight of the water in the soil material, in t, calculated according to the following formula

[0069] m 水 =wm 干 =w(m 湿 -m 水 )

[0070]

[0071] w——The proportion of the weight of water in the soil material to the dry soil, in %;

[0072] Therefore, equation (1) can be adjusted to

[0073]

[0074] According to the definition of density, the above formula can be further written as

[0075]

[0076] G 固 —— is the density of the curing agent, which is 2.75 t / m3 according to a large number of experiments;

[0077] G 干 —— is the density of dry soil. The density of general cohesive soil is 2.70. Considering that the soil may contain more coarse-grained soil, it is recommended to be 2.60 t / m 3 ;

[0078] G 水 —— is the density of water. Whether the water in the soil or the sewage in sewage pond 400, both are 1.0 t / m 3 .

[0079] Substitute all the equations into equation (3)

[0080]

[0081] In the above formula,

[0082] G 水 —— is the density of water. Whether the water in the soil or the sewage in sewage pond 400, it is 1.0 t / m 3 ; G 固 —— is the density of the curing agent, which is 2.75 t / m 3 ;

[0083] G 干 —— is the density of dry soil. The dry density of general soil materials is 2.70 t / m 3 , considering that the local soil materials may contain more coarse-grained soil, it is recommended to be 2.60 t / m 3 ;

[0084] w—— is the proportion of the weight of water in the soil materials to the dry soil, in %, and the drier the soil materials before mixing the curing agent, the greater the amount of sewage treated later. The soil materials before construction need to be properly dried in the sun, so the water content is controlled between 15 - 25%;

[0085] At a given curing agent ratio, generally, it is recommended that the curing agent dosage ratio be α = 20 - 30%, and after measuring the weight of the sewage in sewage pond 400 on-site, the weight of natural soil required to solidify the sewage can be calculated.

[0086] For example, taking a general project as an example, take G 水 = 1.0 t / m3; G 固= 2.75 t / m3; G 干 = 2.70 t / m3; w = 20%; the proportion of the curing agent α = 30%, then the calculation result is

[0087] m 湿 = 0.685 m 污

[0088] That is, for every 1 t of sewage treated, 0.685 t of soil under the above soil indexes is required.

[0089] In this embodiment, in construction step 3), before transporting the solidifying agent 401 to be stacked around the sewage pond 400, a measuring instrument is used to determine the outer perimeter of the sewage pond 400 and the landfill area to be landfilled in the sewage pond 400, and markers are set at the outer perimeter to facilitate subsequent construction.

[0090] In this embodiment, in construction step 3), the sundries around the sewage pond 400 are removed to form a construction belt area surrounding the sewage pond 400, and the solidifying agent 401 is stacked on the construction belt area to facilitate subsequent spreading of the hanging material into the sewage pond 400.

[0091] In this embodiment, in construction step 1), the water content of the collected construction waste soil is measured and processed so that the water content of the construction waste soil is between 15% and 25%.

[0092] In construction step 1), when the water content of the construction waste soil is greater than 15% - 25%, it will be spread out and dried until the water content of the construction waste soil is between 15% and 25%.

[0093] In construction step 1), the construction waste soil is placed in a crushing bucket for crushing to form crushed material, and the crushed material is placed in a vibrating screen for rolling screening to form soil material with a particle size less than 50 mm.

[0094] In construction step 3), after the soil material is independently stirred in a mixer for a set time, the solidifying agent 401 is sprinkled into the mixer until the solidifying agent 401 is stirred and mixed with the soil material to form the above-mentioned solidifying agent 401.

[0095] In this embodiment, in construction step 4), from the outer perimeter to the center of the sewage pond 400, the sewage pond 400 is divided into multiple annular zones, and the multiple annular zones are arranged in a nested manner in sequence and cover the entire sewage pond 400; in construction step 4), along the direction from the outside to the inside of the sewage pond 400, an excavator is used to sprinkle the solidifying agent 401 into a single annular zone. After the solidifying agent 401 sprinkled into the annular zone reacts with the sewage and combines into a fixed landfill body 402, the solidifying agent 401 is then sprinkled into the next annular zone.

[0096] The sewage pond 400 is arranged in sub - regions. After the solidifying material 401 in an annular region combines with sewage to form a solid landfill body 402, the landfill body 402 can be used as a construction platform for the construction of spreading the solidifying material 401 in the next annular region.

[0097] In addition, during the process of landfilling the sewage pond 400, the height and flatness of the landfill body 402 are monitored in real - time. The solidifying material 401 filled into the sewage pond 400 will naturally solidify after a certain period of time. After solidification, necessary maintenance is carried out on the landfill body 402, such as covering with a moisture - retaining film, etc.

[0098] In this embodiment, in construction step 3), the mixer includes a mixing drum 100 arranged horizontally. The mixing drum 100 has a mixing chamber 101 arranged horizontally. The mixing chamber 101 has a mixing shaft 200 arranged horizontally. A plurality of radial shafts 201 are provided on the outer periphery of the mixing shaft 200. Along the axial direction of the mixing shaft 200, the plurality of radial shafts 201 are arranged in a staggered manner.

[0099] The inner ends of the radial shafts 201 are butted against the mixing shaft 200. The mixing shaft 200 is provided with spiral blades 202. The spiral blades 202 are arranged spirally along the circumferential direction of the mixing shaft 200 and are respectively butted and fixed to the outer ends of the plurality of radial shafts 201. The spiral blades 202 have adjacent segments located between adjacent radial shafts 201. A plurality of through - holes are provided on the adjacent segments, and the plurality of through - holes are arranged at intervals along the length direction of the adjacent segments.

[0100] In construction step 3), after the soil material is placed in the mixing chamber 101, the mixing shaft 200 rotates horizontally, driving the spiral blades 202 to rotate synchronously. The spiral blades 202 stir and mix the soil material and the curing agent to form the solidifying material 401. During the stirring and mixing process of the solidifying material 401, it simultaneously passes through the through - holes, is dispersed and then remixed.

[0101] During the rotation of the spiral blades 202, the soil material and the curing agent are stirred to form the solidifying material 40, and during the stirring and mixing process, the solidifying material 401 passing through the through - holes is dispersed and then continuously mixed, so that the solidifying material 401 is more evenly mixed.

[0102] In this embodiment, in construction step 3), two layers of air - jet pipes 300 are provided on the inner side wall of the mixing chamber 101. The air - jet pipes 300 are arranged in a circumferential direction around the mixing chamber 101. The two layers of air - jet pipes 300 are arranged at intervals along the height direction of the mixing chamber 101. A plurality of air - jet micropores are provided on the air - jet pipes 300, and the plurality of paint - spraying micropores are arranged at intervals along the circumferential direction and the circumferential direction of the air - jet pipes 300. The diameter of the air - jet micropores is relatively small, which allows high - pressure gas to be sprayed into the mixing chamber 101. However, the solidifying material 401 in the mixing chamber 101 cannot enter the air - jet pipes 300.

[0103] In construction step 3), during the process that the stirring shaft 200 rotates to stir and mix the solidifying material 401, two layers of air spray pipes 300 spray high-pressure gas into the stirring chamber 101, and the air spray pressures of the two layers of air spray pipes 300 are different and change alternately. The high-pressure gas sprayed by the two layers of air spray pipes 300 performs multi-directional pneumatic stirring on the solidifying material 401.

[0104] In this way, during the process that the stirring shaft 200 stirs and mixes the solidifying material 401, the two layers of air spray pipes 300 synchronously perform pneumatic stirring on the solidifying material 401, and multi-directional stirring is achieved, so as to realize multi-mode and multi-directional stirring of the solidifying material 401 and improve the stirring uniformity.

[0105] The above are only the preferred embodiments of the present invention, and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. Construction method for solidifying sewage in sewage pond by on-site dry mixing of solidified soil, characterized in that, It includes the following construction steps: 1), Collect construction muck, crush and screen the construction muck in sequence to form the required soil material; 2), Arrange a storage tank at the construction site, place the curing agent in the storage tank, and the curing agent includes slag powder, fly ash, waste gypsum, water glass, stone powder slag and slag; 3), According to the design ratio, add the soil material and the curing agent into a mixer and stir and mix them to form a powdery curing material, and transport the curing material to the periphery of the sewage pond for stacking; 4), Spread the curing material into the sewage pond. After the curing material and the sewage are mixed for a set time, the curing material reacts with the sewage to combine and form a solid landfill body.

2. The on-site dry mixing method for solidifying sewage in sewage ponds by using solidified soil according to claim 1, wherein In the construction step 3), before transporting the curing material to the periphery of the sewage pond for stacking, use a measuring instrument to determine the outer boundary of the sewage pond and the landfill area that needs to be landfilled in the sewage pond, and set markers at the outer boundary.

3. The on-site dry mixing method for solidifying the sewage in the sewage pond with solidified soil according to claim 1, characterized in that, In the construction step 3), remove the sundries outside the sewage pond to form a construction belt area surrounding the sewage pond, and stack the curing material on the construction belt area.

4. The on-site dry mixing method for solidifying sewage in sewage ponds with solidified soil as claimed in claim 1, wherein In the construction step 1), measure and process the water content of the collected construction muck so that the water content of the construction muck is between 15% and 25%.

5. The on-site dry mixing method for solidifying sewage in sewage ponds by using solidified soil as claimed in claim 4, wherein, In the construction step 1), when the water content of the construction muck is greater than 15% - 25%, spread it out and dry it until the water content of the construction muck is between 15% and 25%.

6. The on-site dry mixing method for solidifying sewage in sewage ponds by using solidified soil according to any one of claims 1 to 5, characterized in that, In the construction step 1), place the construction muck in a crushing bucket for crushing to form crushed material, and place the crushed material in a drum screen for rolling screening to form a soil material with a particle size less than 50mm.

7. The on-site dry mixing method for solidifying sewage in sewage ponds with solidified soil according to claim 6, characterized in that, In the construction step 3), place the soil material in the mixer and stir it independently for a set time, and then sprinkle the curing agent into the mixer until the curing agent and the soil material are stirred and mixed to form the curing material.

8. The on-site dry mixing method for solidifying sewage in sewage ponds by using solidified soil according to any one of claims 1 to 5, characterized in that, In the construction step 4), divide the sewage pond into multiple annular zones from the periphery to the center of the sewage pond. The multiple annular zones are arranged in a nested manner in sequence and cover the entire sewage pond; In the construction step 4), along the direction from the outside to the inside of the sewage pond, use an excavator to sprinkle the curing material into a single annular zone. When the curing material sprinkled into the annular zone reacts with the sewage to combine into a fixed landfill body, then sprinkle the curing material into the next annular zone.

9. The on-site dry mixing method for solidifying sewage in sewage ponds by using solidified soil according to claim 6, characterized in that, In the construction step 3), the mixer includes a horizontally arranged mixing drum, the mixing drum has a horizontally arranged mixing cavity, the mixing cavity has a horizontally arranged mixing shaft, and a plurality of radial shafts are arranged on the outer periphery of the mixing shaft. Along the axial direction of the mixing shaft, the plurality of radial shafts are arranged in a staggered manner; The inner end of the radial shaft is butted on the mixing shaft, and spiral blades are arranged on the mixing shaft. The spiral blades are arranged spirally along the circumference of the mixing shaft and are respectively butted and fixed with the outer ends of the plurality of radial shafts; the spiral blades have adjacent segments located between adjacent radial shafts, and a plurality of through holes are arranged on the adjacent segments, and the plurality of through holes are arranged at intervals along the length direction of the adjacent segments; In the construction step 3), after the soil material is placed in the mixing chamber, the mixing shaft rotates horizontally, driving the spiral blades to rotate synchronously. The spiral blades stir and mix the soil material and the curing agent to form a cured material. During the stirring and mixing process of the cured material, it simultaneously passes through the through holes, is broken up and then remixed.

10. The on-site dry mixing method for solidifying sewage in sewage ponds using solidified soil as claimed in claim 9, characterized in that, In the construction step 3), two layers of air injection pipes are provided on the inner side wall of the mixing chamber. The air injection pipes are arranged circumferentially around the mixing chamber, and the two layers of air injection pipes are arranged at intervals in the height direction of the mixing chamber. A plurality of air injection micropores are provided on the air injection pipes, and the plurality of paint spraying micropores are arranged circumferentially and at circumferential intervals along the air injection pipes. In the construction step 3), during the process of the mixing shaft rotating to stir and mix the cured material, the two layers of air injection pipes spray high-pressure gas into the mixing chamber, and the air injection pressures of the two layers of air injection pipes are different and alternately change. The high-pressure gas sprayed by the two layers of air injection pipes performs multi-directional pneumatic stirring on the cured material.

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