Method for improving sludge through well point vibration pressing and drying

Abstract

The invention discloses a method for improving sludge by well point vibration pressing and drying, which belongs to the technical field of sludge improvement application and comprises the following steps: S building a cofferdam, blowing sludge into the cofferdam, installing a well point pipe and a water pumping system, performing negative pressure well point dewatering, tamping a soil body, collecting and analyzing a sludge sample, preparing a conditioner, adding the conditioner, mixing organic matters and recycling improved soil. According to the method, in-situ resource utilization of the sludge is achieved, and the method has the dual benefits of environmental protection and economy. By means of the light well point pipe and a matched system, sludge is effectively dried and improved, the waste sludge treatment problem is solved, the engineering construction land requirement is met, and the cost is saved by 49.3% compared with mechanical dehydration drying. And by utilizing a high-concentration soluble conditioner and agricultural decomposed resources, the properties and fertility of the soil are improved, and the backfill soil cost is saved by 13%. The method improves efficiency and normalization, ensures safety and quality, combines comprehensive utilization of organic fertilizer and straw resources, and has significant ecological and environmental protection benefits.

Description

Technical Field

[0001] The invention relates to the technical field of sludge improvement applications, in particular to a well point vibration pressure drying method for improving sludge. Background Art

[0002] Silt soil has the characteristics of high water content, low permeability, high compressibility and low strength. Before improvement and utilization, the natural drying method, vibration compaction method, drainage consolidation method, mechanical dehydration method and other methods are often used to improve the plastic state of the soil.

[0003] At present, the dehydration and reinforcement of sludge abroad usually adopts the admixture method, which is easy to segregate during the mixing process and has poor adhesion with cement slurry. Some domestic projects use the "vacuum preloading method" to increase the internal pressure of the soil through the booster pipe in the soil to accelerate the drainage efficiency. Its cost is high, the construction period is long, it is easily affected by weather conditions, and the strength of recycled soil resources is not high enough. The mechanical dehydration process requires the addition of more lime flocculants during the mud cake consolidation process, so the mud cake is not suitable for reclamation. After consolidation, the bottom mud can be used for filling materials, building materials, etc. The continuity of each production link is poor, and the energy consumption, operating costs and investment are relatively high. Summary of the invention

[0004] In order to overcome the deficiencies of the prior art, the present invention provides a method for improving sludge by vibration and drying at a well point, so that the sludge can be recycled in situ, achieving both environmental and economic benefits.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions: a method for improving sludge by vibration pressure drying at a well point, comprising the following steps:

[0006] S1. Build cofferdams. According to the construction needs, the cofferdams are reasonably distributed and adjusted around the silt dump to isolate the silt dump from the external environment;

[0007] S2, blowing the sludge to be treated into the cofferdam that has been built;

[0008] S3, installing well point pipes and pumping system, installing well point pipes and pumping system in the cofferdam according to the preset well point layout plan;

[0009] S4, negative pressure well point dewatering: start the pumping system, pump water through the well point pipe to dewater the sludge under negative pressure to reduce the water content of the sludge;

[0010] S5. Compact the soil, compact the silt after precipitation to improve the soil density;

[0011] S6. Collect and analyze mud samples, collect mud samples, conduct soil testing and analysis, and understand the physical and chemical properties of mud;

[0012] S7, conditioning agent configuration, according to the sludge test results, configure the corresponding sludge physical and chemical property improver;

[0013] S8, injecting conditioning agent, and reversely pumping the sludge physical and chemical property improver into the sludge through the well point pipe and the supporting pipeline;

[0014] S9, organic matter mixing, dig and mix the decomposed livestock and poultry manure, straw and other organic solid wastes from surrounding farmers with the dried sludge;

[0015] S10: Improved soil reuse: use the improved silt for greening planting or land backfill.

[0016] As a preferred technical solution of the present invention, step S1 specifically includes the following sub-steps:

[0017] Sub-step S101: using relative elevation, the current ground elevation is 0.00, the elevation dimension unit is m, and the other dimension units are all in mm;

[0018] Sub-step S102: The outer cofferdam of the mud discharge area is an earth-rock cofferdam with a top width of 3.0 m, a slope ratio of 1:2, and a weir height of 3.0 m;

[0019] Sub-step S103: The position of the cofferdam is reasonably arranged and adjusted according to the construction needs, and the length is based on the actual filling;

[0020] Sub-step S104: The top width of the drainage outlet cofferdam is 1.5m, the slope ratio is 1:1.5, the weir height is 2.0m, and the bagged soil cofferdam is used. The side slope of the mud discharge area is fully paved with a specification of 300g / m 2 The geotextile extends into the cofferdam for no less than 0.5m, and the height of the cofferdam is gradually increased to the designed position according to the thickness of the silt and the water level.

[0021] Sub-step S105: laying colored strips of cloth within 5m of the drain outlet; the drain pipe is a Φ600 PE solid wall pipe;

[0022] Sub-step S106: Before the cofferdam is built, the silt or topsoil at the embankment foundation should be removed, and the backfill soil should be clay soil with a compaction degree of not less than 0.91.

[0023] As a preferred technical solution of the present invention, step S2 specifically includes the following sub-steps:

[0024] Sub-step S201: using a mixture of silty soil and fine sand as the main component of the dredger fill;

[0025] Sub-step S202: using the casing and punching method for construction, a 20 cm PVC pipe is inserted into the wellbore and the hole depth is 0.3-0.6 m deeper than the bottom of the filter tube;

[0026] Sub-step S203: After washing the hole, insert the well point pipe, and fill the space between the well point pipe and the PVC pipe with medium-coarse sand in time to make it dense. The amount of filter material should be greater than 40% to 50% of the designed amount. The three processes of punching and drilling, installing the well point pipe, and filling the filter material should be carried out continuously.

[0027] Sub-step S204: After the PVC pipe is pulled out, pour clean water into the well point pipe to check the water seepage effect, and it is appropriate to see bubbles on the ground surface.

[0028] As a preferred technical solution of the present invention, step S3 specifically includes the following sub-steps:

[0029] Sub-step S301: Determine the well point layout according to the plan shape and size of the foundation pit, geological and hydrological conditions, engineering properties, precipitation depth, surrounding terrain, etc.;

[0030] Sub-step S302: for the treatment of large-area backfill soil, multiple rows of well points are used;

[0031] Sub-step S303: The well point pipe is arranged 3m away from the cofferdam, the well point spacing is set at 2m, and the buried depth of the well point pipe is controlled to be about 3m, with the bottom end of the filter pipe penetrating into the bottom of the dredger fill soil;

[0032] Sub-step S304: The height of the well point pipe exposed above the ground is 10-25 cm.

[0033] As a preferred technical solution of the present invention, in step S4, the water inflow of the well foundation pit should be calculated during the negative pressure dewatering by pumping;

[0034] The water inflow of the well foundation pit can be expressed as:

[0035]

[0036] Where k is the soil permeability coefficient, H is the aquifer thickness, Sw is the well water level drawdown, and the precipitation impact radius R should be determined through experiments or based on local experience.

[0037] As a preferred technical solution of the present invention, in step S4, the equivalent radius of the rectangular foundation pit should be calculated for the negative pressure dewatering by pumping;

[0038] The equivalent radius of a rectangular foundation pit can be expressed as:

[0039]

[0040] In the formula, r 0 is the equivalent radius of the foundation pit, A is the area of ​​the lowered water surface, and π is the circumference of a circle, which is approximately 3.1415.

[0041] As a preferred technical solution of the present invention, in step S4, the water inflow of the foundation pit should be calculated during the negative pressure dewatering by pumping;

[0042] The amount of water inflow from foundation pit can be expressed as:

[0043] Q = kH (Sw / R) A.

[0044] As a preferred technical solution of the present invention, in step S6, the soil detection and analysis specifically involves sampling and analyzing the silt soil to detect and analyze the main indicators such as organic matter content, available potassium, available phosphorus, total nitrogen, alkaline nitrogen and other nutrient contents, pH value, soil cation exchange capacity, heavy metals such as lead, cadmium, arsenic, mercury and zinc, total microbial colony count and fungal toxins in the soil.

[0045] As a preferred technical solution of the present invention, step S8 specifically includes the following sub-steps:

[0046] Sub-step S801: using a pump to pump the prepared soil improvement mixed solvent into the consolidated silt soil in the reverse direction through the conduit and the infiltration pipe;

[0047] Sub-step S802: the perfusion process lasts about 3 minutes;

[0048] Sub-step S803: lifting the well point pipe by 1.5 meters and then pouring;

[0049] Sub-step S804: As the injection continues, the well point pipe will be gradually pulled out until the well point pipe is pulled out to improve the silt soil.

[0050] As a preferred technical solution of the present invention, in step S9, according to the silt soil sample detection and analysis report, the decomposed livestock and poultry manure, straw, etc. of the surrounding farmers can be used to loosen and mix the dried soil, and then transported to the project area for soil backfilling for greening planting.

[0051] Compared with the prior art, the present invention can achieve the following beneficial effects:

[0052] 1. In-situ sludge resource utilization: Use light well point pipes and supporting systems to dry sludge in temporary sludge storage yards, use soil testing and formulation technology and recyclable agricultural resources to improve sludge and reuse it for greening. Through consolidation technology, sludge can be recycled in situ without being transported outside, which not only solves the problem of waste sludge treatment, but also meets the demand for land and earth resources for engineering construction. This method saves 49.3% of the cost compared with mechanical dehydration and drying of sludge.

[0053] 2. Improvement of soil physical and chemical properties and cost savings: Utilize soil testing and formulation technology and recyclable agricultural resources to improve silt and reuse it for greening. Use soil testing and formulation technology and high-concentration soluble conditioners, combined with agricultural decomposed resources, to improve the physical and chemical properties and fertility of silt soil. Compared with general soil backfilling and covering 30cm or 1.5m planting holes with planting soil, it can save 13% of costs, improve soil utilization efficiency, and achieve significant improvement in economic benefits.

[0054] 3. Ecological and environmental benefits and work process optimization: Comprehensive consideration of sludge precipitation, physical and chemical properties improvement and transportation, etc., improves the work process efficiency and operational standardization, ensures the safety of construction operations and the effect of precipitation improvement sludge control; at the same time, the improved sludge is combined with a large amount of organic fertilizer and straw resources in agriculture and rural areas for comprehensive utilization, reducing environmental impact and achieving outstanding ecological and environmental benefits. This innovative method not only effectively treats sludge, but also improves environmental quality and achieves sustainable development. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] Figure 1 It is a schematic diagram of the overall method flow of the present invention;

[0056] Figure 2 A schematic diagram of the construction method of the silt cofferdam provided by the present invention;

[0057] Figure 3 A schematic cross-sectional view of an earth-rock cofferdam and a drainage pocket cofferdam provided by the present invention;

[0058] Figure 4 This is a schematic diagram of the plan layout of the well point pipe and pumping system provided by the present invention. DETAILED DESCRIPTION

[0059] The preferred embodiments of the present invention will be described in detail below in conjunction with the accompanying drawings, wherein the accompanying drawings constitute a part of the present invention and are used together with the embodiments of the present invention to illustrate the principles of the present invention, but are not used to limit the scope of the present invention.

[0060] Example:

[0061] like Figure 1 - Figure 4 As shown, this embodiment proposes a method for improving sludge by vibration and pressure drying at a well point, comprising the following steps:

[0062] S1. Build cofferdams. According to the construction needs, the cofferdams are reasonably distributed and adjusted around the silt dump to isolate the silt dump from the external environment;

[0063] S2, blowing the sludge to be treated into the cofferdam that has been built;

[0064] S3, installing well point pipes and pumping system, installing well point pipes and pumping system in the cofferdam according to the preset well point layout plan;

[0065] S4, negative pressure well point dewatering: start the pumping system, pump water through the well point pipe to dewater the sludge under negative pressure to reduce the water content of the sludge;

[0066] S5. Compact the soil, compact the silt after precipitation to improve the soil density;

[0067] S6. Collect and analyze mud samples, collect mud samples, conduct soil testing and analysis, and understand the physical and chemical properties of mud;

[0068] S7, conditioning agent configuration, according to the sludge test results, configure the corresponding sludge physical and chemical property improver;

[0069] S8, injecting conditioning agent, and reversely pumping the sludge physical and chemical property improver into the sludge through the well point pipe and the supporting pipeline;

[0070] S9, organic matter mixing, dig and mix the decomposed livestock and poultry manure, straw and other organic solid wastes from surrounding farmers with the dried sludge;

[0071] S10: Improved soil reuse: use the improved silt for greening planting or land backfill.

[0072] The specific implementation methods of the above steps are described in detail below:

[0073] In step S1 of the present invention, before building the cofferdam, the on-site topography, geology and hydrological conditions should be investigated in detail to ensure the stability and safety of the cofferdam. The construction location and size of the cofferdam should be reasonably adjusted according to construction needs to ensure that the sludge dump can be completely isolated. During the construction process, the material quality and construction quality of the cofferdam should be strictly controlled to ensure the strength and durability of the cofferdam.

[0074] Specifically, the outer cofferdam of the mud discharge area is an earth-rock cofferdam with a top width of 3.0m, a slope ratio of 1:2, and a weir height of 3.0m. During the filling process, the thickness and compaction of the filling layer should be strictly controlled to ensure the density and stability of the cofferdam. The earth-rock cofferdam has the advantages of simple structure, convenient material acquisition, and low cost. It is suitable for the outer cofferdam of the mud discharge area of ​​this project. The design of the top width and slope ratio can ensure the stability and anti-scouring ability of the cofferdam, and effectively prevent the overflow of silt and water;

[0075] Specifically, the location of the cofferdam is reasonably arranged and adjusted according to the construction needs, and the length is based on the actual filling, which can ensure the smooth progress of the construction process and the complete isolation of the sludge dump. At the same time, it can also be flexibly adjusted according to the actual situation on site to improve construction efficiency and flexibility. During the adjustment process, attention should be paid to the coordination and aesthetics with the surrounding environment to avoid adverse effects on the surrounding environment;

[0076] Specifically, the top width of the spillway cofferdam is 1.5m, the slope ratio is 1:1.5, and the weir height is 2.0m. The bagged soil cofferdam is used to ensure the stability and safety of the spillway. The full paving specification of the side slope of the mud discharge area is 300g / m 2 The geotextile can enhance the anti-scouring ability of the cofferdam and improve its durability. The length of the geotextile extending into the cofferdam is not less than 0.5m to ensure the close fit between the geotextile and the cofferdam. The height of the cofferdam is gradually increased to the designed position according to the thickness of the silt and the water level.

[0077] Specifically, colored strips are laid within 5m of the drain outlet; the drain pipe is a Φ600PE solid wall pipe. The colored strips laid at the drain outlet can prevent silt and water from polluting and clogging the drain outlet. The setting of the drain pipe can ensure the smooth discharge of silt and water and improve drainage efficiency;

[0078] Specifically, the silt or topsoil at the embankment foundation should be removed before the cofferdam is filled. Removing the silt or topsoil at the embankment foundation can prevent pollution and adverse effects on the filling materials. Clay soil should be used for backfill. The selection of backfill soil and the control of compaction degree can ensure the density and stability of the cofferdam. The compaction degree should not be less than 0.91.

[0079] In step S2 of the present invention, the sludge to be treated is blown into the built cofferdam, and the isolation effect of the cofferdam can be effectively utilized to centrally treat the sludge. This step is a key link in the sludge treatment project and provides the necessary conditions and basis for subsequent treatment work;

[0080] Specifically, a mixture of silty soil and fine sand is used as the main component of the dredger fill soil. The soil has high water content, is very soft, and has good water permeability and compressibility. It can effectively improve the density and stability of the dredger fill soil and provide favorable conditions for subsequent processing work.

[0081] Specifically, the casing and punching method are used for construction. After the traditional high-pressure water gun punching method forms a hole, the hole wall is very easy to shrink and collapse, blocking the filter tube. The wellbore is inserted with a 20cm PVC pipe and the hole depth is 0.3-0.6m deeper than the bottom of the filter tube;

[0082] Specifically, after washing the hole, insert the well point pipe, and fill the space between the well point pipe and the PVC pipe with medium-coarse sand in time. The amount of filter material should be greater than 40% to 50% of the designed amount. The three processes of punching and drilling, installing the well point pipe, and filling the filter material should be carried out continuously. Washing the hole can remove impurities and residues in the well hole, and provide a clean environment for the installation of the well point pipe and the filling of the filter material. The installation of the well point pipe and the filling of the filter material are the key links of the well point dewatering system, which directly affect the dewatering effect and engineering quality.

[0083] Specifically, after the PVC pipe is pulled out, pour clean water into the wellpoint pipe to check the water seepage effect. It is appropriate to see bubbles on the ground surface. Pouring clean water into the wellpoint pipe can check the water seepage effect and performance of the wellpoint dewatering system. By observing the bubbles on the ground surface, the working status and effect of the wellpoint dewatering system can be judged, which provides an important reference for subsequent processing work. Attention should be paid to observing the stability and abnormal conditions of the wellpoint dewatering system, and timely measures should be taken to deal with them.

[0084] In step S3 of the present invention, well point pipes and a pumping system are installed. The well point pipes and the pumping system are installed in the cofferdam according to a preset well point arrangement plan. By reasonably arranging the well point pipes, the groundwater in the foundation pit can be effectively pumped out, the groundwater level can be lowered, and favorable conditions can be provided for subsequent foundation pit excavation and construction. At the same time, the operation of the pumping system can also maintain a dry environment in the foundation pit, which is conducive to the smooth progress of the project and ensures the quality of the project. Before installing the well point pipes and the pumping system, the geological and hydrological conditions of the foundation pit, as well as the surrounding terrain and engineering properties, should be fully understood to ensure the rationality and feasibility of the well point arrangement plan;

[0085] Specifically, the well point layout is determined according to the plane shape and size of the foundation pit, geological and hydrological conditions, engineering properties, precipitation depth, surrounding terrain, etc., which can ensure the best precipitation effect. At the same time, it can also avoid excessive or insufficient precipitation, save resources and costs, and the geological and hydrological conditions of the foundation pit should be surveyed and analyzed in detail to determine the specific parameters and locations of the well point layout;

[0086] Specifically, for the treatment of large-area backfill soil, the use of multiple rows of well points can effectively improve the precipitation efficiency and shorten the construction period. The arrangement of multiple rows of well points can also enhance the stability and reliability of the precipitation system and ensure that the precipitation effect meets the design requirements. Each row of well points should be numbered and marked to facilitate subsequent management and maintenance;

[0087] Specifically, the well point pipe is arranged 3m away from the cofferdam, the well point spacing is set at 2m, and the buried depth of the well point pipe is controlled at about 3m, with the bottom of the filter pipe penetrating into the bottom of the blown fill soil as the standard. Reasonable arrangement of the well point pipe can ensure the normal operation and precipitation effect of the precipitation system. The buried depth of the well point pipe should be controlled within a reasonable range to ensure that the bottom of the filter pipe can penetrate into the bottom of the blown fill soil to achieve the best precipitation effect;

[0088] Specifically, the height of the well-point pipe above the ground is 10-25cm. Reasonable determination of the height of the well-point pipe above the ground can facilitate subsequent management and maintenance work, and can also prevent the well-point pipe from being damaged and affected by the external environment. When determining the height of the well-point pipe above the ground, the surrounding environment and engineering requirements should be fully considered to avoid adverse effects on the well-point pipe.

[0089] In step S4 of the present invention, the water pumping negative pressure precipitation is calculated;

[0090] The water inflow of the well foundation pit can be expressed as:

[0091]

[0092] The equivalent radius of a rectangular foundation pit can be expressed as:

[0093]

[0094] The amount of water inflow from foundation pit can be expressed as:

[0095] Q=kH(Sw / R)A

[0096] Where k is the soil permeability coefficient, H is the aquifer thickness, Sw is the well water level drawdown, R is the impact radius of the precipitation, and r is the 0 is the equivalent radius of the foundation pit, A is the area of ​​the lowered water surface, and π is the circumference of a circle, which is approximately 3.1415 and should be determined through experiments or based on local experience.

[0097] Specifically, calculating the water inflow of the well foundation pit directly determines the design and operation efficiency of the precipitation system. Accurately calculating the water inflow can reasonably determine the number and power of the pumping equipment, avoid waste of resources and insufficient precipitation. Accurate calculation of the equivalent radius is of great significance for evaluating the stability and precipitation effect of the foundation pit. The water inflow of the foundation pit can more accurately evaluate the effect of the precipitation system and provide strong data support for subsequent foundation pit excavation and construction.

[0098] In step S6 of the present invention, soil detection and analysis specifically involves sampling and analyzing the silt soil to detect and analyze the main indicators such as organic matter content, available potassium, available phosphorus, total nitrogen, alkaline nitrogen and other nutrient contents in the soil, pH value, soil cation exchange capacity, heavy metals such as lead, cadmium, arsenic, mercury and zinc, total microbial colony count and mycotoxins. Through scientific sampling methods, the overall condition of the silt soil can be truly reflected, providing a reliable basis for subsequent detection. Contamination should be avoided during sampling, clean sampling tools should be used, and the sampling points should be representative. The sampling depth should be moderate to obtain soil information at different levels. Samples should be properly preserved to avoid deterioration during transportation and storage, which helps to accurately assess soil quality.

[0099] In step S7 of the present invention, according to the silt soil sample detection and analysis report, the instant conditioning agents such as beneficial bacteria, alginic acid, humic acid, chitin are equipped, and the various functional groups such as awn fragrant core, hydroxyl, carboxyl, carbonyl, methoxyl and a large number of beneficial microbial flora in the conditioning agent are promoted while meeting the economy. It can cement the soil together, increase the soil voids, thereby improving the soil water retention and fertilizer retention capacity. Biological bacteria, through the activities of biological bacteria, can not only improve the physical and chemical properties of the soil, improve the content and conversion efficiency of soil organic matter, but also have the functions of potassium solution, phosphorus release and nitrogen fixation. After the biological bacterial fertilizer is applied to the soil, the biological bacteria quickly proliferates, forms a group advantage, decomposes the nitrogen, phosphorus and potassium that are fixed in the soil and cannot be absorbed and utilized by plants, and fixes the free nitrogen in the air for crop absorption and utilization, allowing the soil to form more granular structures, and the physical and chemical properties are changed from bad to good, while inhibiting the formation of harmful bacteria in the soil, avoiding the infection of soil-borne diseases.

[0100] In step S8 of the present invention, the sludge physical and chemical property improver is pumped into the sludge through the well point pipe and the supporting pipeline in reverse order to improve the soil structure and soil fertility, thereby achieving the purpose of improving the sludge soil;

[0101] Specifically, the prepared soil improvement mixed solvent is pumped into the consolidated silt soil through the conduit and the percolation pipe in the reverse direction by a water pump. The key to this step is to ensure that the mixed solvent can penetrate evenly and deeply into the soil, laying the foundation for subsequent improvement work;

[0102] Specifically, the pouring process lasts about 3 minutes, and as the soil resistance gradually increases, the pressure will also increase accordingly;

[0103] Specifically, the well point pipe is lifted 1.5 meters before injection. The purpose of this operation is to allow the mixed solvent to penetrate deeper into different layers of the soil, avoiding excessive accumulation of the amendment in a certain layer, thereby ensuring a more uniform and comprehensive improvement effect;

[0104] Specifically, as the irrigation continues, the well point pipe will be gradually pulled out until the well point pipe is pulled out to improve the silt soil. During this process, the mixed solvent forms a continuous improvement layer in the soil, which not only effectively improves the soil structure, but also significantly improves the soil fertility. More importantly, this method ensures that the improver can be evenly distributed in all layers of the soil, avoiding the problem of uneven local improvement that may occur in traditional improvement methods.

[0105] In step S9 of the present invention, according to the silt soil sample detection and analysis report, the decomposed livestock and poultry manure, straw, etc. of the surrounding farmers can be used to dig loose and mix with the dried soil, and then transported to the project area for soil backfilling for greening planting;

[0106] Specifically, according to the silt soil sample test and analysis report, it is equipped with beneficial bacteria, alginic acid, humic acid, chitin and other quick-dissolving conditioners, which promotes the various functional groups such as awn nucleus, hydroxyl, carboxyl, carbonyl, methoxyl and a large number of beneficial microbial flora in the conditioner while meeting the economic efficiency. It can cement the soil together, increase the soil voids, and thus improve the soil's ability to retain water and fertilizer. Biological bacteria, through the activities of biological bacteria, can not only improve the physical and chemical properties of the soil, increase the content and conversion efficiency of soil organic matter, but also have the functions of potassium release, phosphorus release and nitrogen fixation. After the biological fertilizer is applied to the soil, the biological bacteria will proliferate quickly, forming a group advantage, decomposing the nitrogen, phosphorus and potassium that are fixed in the soil and cannot be absorbed and utilized by plants, and fixing the free nitrogen in the air for crops to absorb and utilize, so that the soil forms more granular structures, and the physical and chemical properties change from bad to good. At the same time, it inhibits the formation of harmful bacteria in the soil to avoid the infection of soil-borne diseases.

[0107] In step S10 of the present invention, according to the silt soil sample detection and analysis report, the decomposed livestock and poultry manure, straw, etc. of the surrounding farmers can be used to dig loose and mix with the dried soil, and then transported to the project area for soil backfilling for greening planting;

[0108] Specifically, it regulates the physical and chemical properties of the soil. Adding organic solid waste to the soil will also increase the looseness of the soil, increase the pore structure, and improve the water retention capacity of the soil;

[0109] Specifically, to improve soil fertility, organic solid waste has a high organic matter content, which can quickly improve soil organic matter and fertility;

[0110] Specifically, organic matter improvers can improve soil biological activity and diversity. They can provide carbon sources and energy for microorganisms, which significantly improves the activity of soil microorganisms and increases the diversity of microorganisms.

[0111] It can be seen that the well point vibration pressure drying and sludge improvement method provided by the present invention can make sludge in-situ resource, environmental protection and economic benefits, use light well point pipes and supporting systems to dry sludge in temporary sludge storage yards, use light well point pipes and supporting systems to reversely pump sludge physical and chemical property improvers to improve sludge soil, use soil testing and formulation technology and recyclable agricultural resources to improve sludge and reuse it for greening;

[0112] The sludge of the present invention does not need to be transported outside, and the consolidation technology is used to utilize the sludge in situ, which not only solves the problem of waste sludge treatment, but also meets the demand for land and earth resources for engineering construction, saving 49.3% of the cost compared with mechanical dehydration and drying of sludge.

[0113] Using high-concentration soluble conditioners and agricultural decomposed resources to improve soil physical and chemical properties and fertility can save 13% of the cost compared to the planting soil covering the 30cm or 1.5m planting hole after backfilling with general soil, with obvious economic benefits;

[0114] In summary, the present invention takes into account silt precipitation, improvement of silt physical and chemical properties and silt transportation, and utilizes silt as a resource in situ after consolidation, which can effectively treat silt, improve environmental quality, improve work process efficiency and operational standardization, ensure construction safety and the effect of precipitation and silt control, improve work efficiency and reduce environmental impact, and at the same time, the improved silt is combined with a large amount of organic fertilizer and straw resources in agriculture and rural areas for comprehensive utilization, with outstanding ecological and environmental benefits.

[0115] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0116] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited by the above implementation regulations. The above implementation regulations and descriptions are only preferred examples of the present invention and are not used to limit the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A method for improving sludge by vibration and pressure drying at a well point, characterized in that: The following steps are involved: S1. Build cofferdams. According to the construction needs, the cofferdams are reasonably distributed and adjusted around the silt dump to isolate the silt dump from the external environment; S2, blowing mud into the cofferdam, blowing the sludge to be treated into the built cofferdam; S3, installing well point pipes and pumping system, installing well point pipes and pumping system in the cofferdam according to the preset well point layout plan; S4, negative pressure well point precipitation; Start the pumping system to pump water through the well point pipe to reduce the water content of the sludge by negative pressure. S5. Compact the soil, compact the silt after precipitation to improve the soil density; S6. Collect and analyze mud samples, collect mud samples, conduct soil testing and analysis, and understand the physical and chemical properties of mud; S7, conditioning agent configuration, according to the sludge test results, configure the corresponding sludge physical and chemical property improver; S8, injecting conditioning agent, and reversely pumping the sludge physical and chemical property improver into the sludge through the well point pipe and the supporting pipeline; S9, organic matter mixing, dig and mix the decomposed livestock and poultry manure, straw and other organic solid wastes from surrounding farmers with the dried sludge; S10: Improved soil reuse: use the improved silt for greening planting or land backfill.

2. A method for improving sludge by vibration and drying at a well point according to claim 1, characterized in that: The step S1 specifically includes the following sub-steps: Sub-step S101: using relative elevation, the current ground elevation is 0.00, the elevation dimension unit is m, and the other dimension units are all in mm; Sub-step S102: The outer cofferdam of the mud discharge area is an earth-rock cofferdam with a top width of 3.0 m, a slope ratio of 1:2, and a weir height of 3.0 m; Sub-step S103: The position of the cofferdam is reasonably arranged and adjusted according to the construction needs, and the length is based on the actual filling; Sub-step S104: The top width of the drainage outlet cofferdam is 1.5m, the slope ratio is 1:1.5, the weir height is 2.0m, and the bagged soil cofferdam is used. The side slope of the mud discharge area is fully paved with a specification of 300g / m 2 The geotextile extends into the cofferdam for no less than 0.5m, and the height of the cofferdam is gradually increased to the designed position according to the thickness of the silt and the water level. Sub-step S105: laying colored strips of cloth within 5m of the drain outlet; the drain pipe is a Φ600 PE solid wall pipe; Sub-step S106: Before the cofferdam is built, the silt or topsoil at the embankment foundation should be removed, and the backfill soil should be clay soil with a compaction degree of not less than 0.

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3. A method for improving sludge by vibration and drying at a well point according to claim 1, characterized in that: The step S2 specifically includes the following sub-steps: Sub-step S201: using a mixture of silty soil and fine sand as the main component of the dredger fill; Sub-step S202: using the casing and punching method for construction, a 20 cm PVC pipe is inserted into the wellbore and the hole depth is 0.3-0.6 m deeper than the bottom of the filter tube; Sub-step S203: After washing the hole, insert the well point pipe, and fill the space between the well point pipe and the PVC pipe with medium-coarse sand in time to make it dense. The amount of filter material should be greater than 40% to 50% of the designed amount. The three processes of punching and drilling, installing the well point pipe, and filling the filter material should be carried out continuously. Sub-step S204: After the PVC pipe is pulled out, pour clean water into the well point pipe to check the water seepage effect, and it is appropriate to see bubbles on the ground surface.

4. A method for improving sludge by vibration and drying at a well point according to claim 1, characterized in that: The step S3 specifically includes the following sub-steps: Sub-step S301: Determine the well point layout according to the plan shape and size of the foundation pit, geological and hydrological conditions, engineering properties, precipitation depth, surrounding terrain, etc.; Sub-step S302: for the treatment of large-area backfill soil, multiple rows of well points are used; Sub-step S303: The well point pipe is arranged 3m away from the cofferdam, the well point spacing is set at 2m, and the buried depth of the well point pipe is controlled to be about 3m, with the bottom end of the filter pipe penetrating into the bottom of the dredger fill soil; Sub-step S304: The height of the well point pipe exposed above the ground is 10-25 cm.

5. A method for improving sludge by vibration and drying at a well point according to claim 1, characterized in that: In step S4, the water inflow of the well foundation pit should be calculated by pumping negative pressure dewatering; The water inflow of the well foundation pit can be expressed as: Where k is the soil permeability coefficient, H is the aquifer thickness, Sw is the well water level drawdown, and the precipitation impact radius R should be determined through experiments or based on local experience.

6. A method for improving sludge by vibration and drying at a well point according to claim 5, characterized in that: In step S4, the equivalent radius of the rectangular foundation pit should be calculated for negative pressure dewatering by pumping water; The equivalent radius of a rectangular foundation pit can be expressed as: In the formula, r0 is the equivalent radius of the foundation pit, A is the area of ​​the lowered water surface, and π is the pi, which is approximately 3.1415.

7. A method for improving sludge by vibration and drying at a well point according to claim 6, characterized in that: In step S4, the water inflow from the foundation pit should be calculated by pumping negative pressure precipitation; The amount of water inflow from foundation pit can be expressed as: Q = kH (Sw / R) A.

8. The method for improving sludge by vibration and drying at a well point according to claim 1, characterized in that: In step S6, the soil detection and analysis specifically involves sampling and analyzing the silt soil to detect and analyze the main indicators such as organic matter content, available potassium, available phosphorus, total nitrogen, alkaline nitrogen and other nutrient contents, pH value, soil cation exchange capacity, heavy metals such as lead, cadmium, arsenic, mercury and zinc, total microbial colony count and fungal toxins in the soil.

9. A method for improving sludge by vibration and drying at a well point according to claim 1, characterized in that: The step S8 specifically includes the following sub-steps: Sub-step S801: using a pump to pump the prepared soil improvement mixed solvent into the consolidated silt soil in the reverse direction through the conduit and the infiltration pipe; Sub-step S802: the perfusion process lasts about 3 minutes; Sub-step S803: lifting the well point pipe by 1.5 meters and then pouring; Sub-step S804: As the injection continues, the well point pipe will be gradually pulled out until the well point pipe is pulled out to improve the silt soil.

10. The method for improving sludge by vibration and drying at a well point according to claim 1, characterized in that: In step S9, according to the silt soil sample detection and analysis report, the decomposed livestock and poultry manure, straw, etc. of the surrounding farmers can be used to loosen and mix with the dried soil, and then transported to the project area for soil backfilling for greening planting.

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