Two-section normal-temperature sludge dewatering and mechanical drying system

Abstract

The utility model provides a two-section type normal-temperature sludge dewatering and mechanical drying system which sequentially comprises sludge deep dewatering equipment, an auxiliary material storing and adding device, a material mixing device and sludge mechanical drying equipment, the auxiliary material storing and adding device is used for storing auxiliary materials with a drainage effect and adding the auxiliary materials with the weight being 3-10% of that of the to-be-dried sludge into the to-be-dried sludge, and the mixing device comprises a sludge conveying device for mixing the to-be-dried sludge with the added auxiliary materials and conveying the mixture to the sludge mechanical drying equipment at the rear end; the sludge mechanical drying equipment can be used for carrying out filter pressing on a mixture of the to-be-dried sludge treated by the mixing device and the auxiliary materials; within the set filter pressing time, the working pressure is slowly increased from the initial pressure until the maximum set pressure is at least greater than 1.5 Mpa / cm < 2 >. The system can realize mechanical drying of sludge, does not need a heat source for drying, and is low in energy consumption.

Description

Technical Field

[0001] This utility model relates to the field of sludge treatment technology, and in particular to a two-stage ambient temperature sludge dewatering and mechanical drying system. Background Technology

[0002] A crucial step in wastewater treatment is separating water from sludge to reduce its volume and alleviate the sludge volume load on subsequent treatment processes. Different treatment processes are employed depending on the sludge's moisture content. When reducing the sludge moisture content from over 90% to 60-70%, sludge dewatering is used, traditionally achieved through mechanical filtration. When further reducing the moisture content from 60-70% to as low as 10%, drying processes are employed, typically utilizing gas-fired boilers or heat pump units that convert electrical energy into heat. Regardless of the energy source, sludge drying ultimately relies on thermal energy.

[0003] In sludge dewatering processes, the initial sludge moisture content is approximately 97%-99%. Depending on the mechanical filtration method, the moisture content of the sludge after primary dewatering varies: taking screw presses, centrifugal dewatering machines, and conventional belt filter presses as examples, sludge is dewatered from 97%-99% to around 80%, resulting in a primary dewatering sludge moisture content of approximately 80%, which is high. In contrast, sludge treated by deep dewatering equipment such as plate and frame filter presses and high-pressure belt filter presses has a lower moisture content, dewatering from 97%-99% to around 60%-70%, resulting in a primary dewatering sludge moisture content of approximately 60%-70%. To further reduce the moisture content of the primary dewatering sludge under these primary dewatering conditions, it is possible to add a large amount of lime powder during plate and frame filter press operation, thereby achieving a lower moisture content for the primary dewatered sludge. However, the sludge treated with added lime powder cannot be rendered harmless or utilized as a resource. Even if incineration is chosen, the addition of a large amount of lime powder necessitates a large amount of auxiliary heat source for combustion, leading to increased disposal costs.

[0004] To obtain sludge with a moisture content suitable for downstream disposal, current sludge treatment systems partially employ a two-stage process. This primarily involves using screw presses, belt filter presses, or plate and frame filter presses combined with subsequent thermal drying equipment such as low-temperature drying or steam drying. However, both low-temperature and steam drying require significant auxiliary heat sources, resulting in high operating costs and low energy reuse efficiency. Therefore, sludge drying becomes the main energy-consuming stage of the sludge treatment system and a key focus for achieving energy conservation and cost reduction. Furthermore, the drying process carries the risk of spontaneous combustion of sludge dust, highlighting significant drawbacks of these thermal drying methods in sludge treatment. Utility Model Content

[0005] In the research on sludge drying treatment addressing the above-mentioned technical problems, the inventors discovered that: 1) In sludge that has undergone deep dewatering (with a moisture content of 60%-70%), in addition to the water inside the sludge particles, there is still water outside the sludge particles. At room temperature, this water outside the particles is tightly adsorbed on the outer surface of the sludge particles and forms a pressure balance with the water inside the sludge particles. This is one of the important reasons why it is difficult to filter out more water and effectively reduce the moisture content of sludge by ordinary mechanical pressure filtration in the sludge drying process; 2) Under the above conditions, by uniformly mixing the auxiliary material with the sludge with a moisture content of 60%-70% with the material and applying slight pressure through pressure filtration, when the external pressure reaches 1.5 MPa / cm^2, the water output suddenly increases, and the pressure can be further increased after this cell wall breaking pressure to mechanically dry the sludge that has undergone deep dewatering to the degree required for the sludge downstream disposal method. Based on the above findings, the inventors summarized and constructed the following principle of sludge cell disruption by ambient temperature flow and pressure difference: By uniformly mixing auxiliary materials with a flow-guiding effect and sludge with a moisture content of 60%-70% and then feeding them into a mechanical drying device, slight pressure is applied through filter press. Under the flow-guiding effect of the auxiliary materials, the water on the outside of the particles, especially the water tightly adsorbed on the outer surface of the sludge particles, will be discharged, thereby breaking the balance between the water inside and outside the sludge particles, thus creating a pressure difference between the inside and outside of the sludge particles. However, the pressure difference is small at this time. Subsequently, after the external pressure is applied, the pressure difference between the inside and outside of the sludge particles increases until the sludge particles rupture, producing a cell disruption effect and discharging the internal water.

[0006] "Cell wall breaking" usually refers to a method that causes cell walls to rupture under the interference of external factors. In this invention, it refers to a method that breaks the pressure balance between the inside and outside of sludge particles under the dual action of external pressure and auxiliary materials, thereby releasing the water inside the sludge particles.

[0007] Based on the above-mentioned principle of sludge room temperature flow pressure difference cell breaking, this utility model provides a two-stage room temperature sludge dewatering and mechanical drying system. In the drying process stage, it can filter out most of the water in the sludge that has undergone deep dewatering (moisture content of 60%-70%) through sludge mechanical drying equipment, thereby further reducing its moisture content to the level required for the sludge's downstream disposal method (such as incineration, composting, etc.). The drying process is carried out at room temperature, without the need for a heat source, with low energy consumption, simple operation, and high efficiency.

[0008] To achieve the above objectives, this utility model provides a two-stage ambient temperature sludge dewatering and mechanical drying system, comprising at least, in sequence, a sludge deep dewatering device, an auxiliary material storage and adding device, a mixing device, and a sludge mechanical drying device. The sludge deep dewatering device is configured to deeply dewater initial sludge into sludge to be dried. The auxiliary material storage and adding device is configured to store auxiliary materials with a guiding effect and add the auxiliary materials, at a weight of 3-10% of the weight of the sludge to be dried, to the sludge to be dried. The mixing device includes at least a sludge conveying device, which is configured to mix the sludge to be dried with the added auxiliary materials and convey it to the downstream sludge mechanical drying device. The sludge mechanical drying device is configured to perform pressure filtration on the mixture of sludge to be dried and auxiliary materials processed by the mixing device. During the set pressure filtration time, the working pressure is slowly increased from the initial pressure until the pressure reaches the maximum set pressure, which is at least greater than 1.5 MPa / cm^2.

[0009] In a preferred embodiment of the present invention, the mixing device may further include a crushing device disposed between the sludge conveying device and the sludge mechanical drying equipment, and configured to further and fully mix the sludge to be dried with the auxiliary material by stirring and crushing.

[0010] According to this invention, under the slight action of the initial external pressure applied by the sludge mechanical drying equipment and the guiding effect of the auxiliary material, the external water of the sludge particles to be dried is rapidly discharged, creating a small pressure difference between the inside and outside of the sludge particles. Subsequently, after the external water is discharged and the pressure balance between the internal and external water of the sludge particles is disrupted, the pressure difference between the inside and outside of the particles gradually increases as the system pressure increases, eventually causing the particles to rupture, producing a cell-wall breaking effect, and releasing the water inside the particles.

[0011] According to this invention, the sludge to be dried is sludge treated by the deep dewatering equipment. Similar to the sludge dewatered to 60%-70% as used in the aforementioned industry classification of drying processes, it is granular, possesses certain solid-state characteristics, and when mixed and pressed with the auxiliary material, this type of dewatered sludge can better solidify and form. The preferred moisture content of the sludge to be dried is 60%-70%.

[0012] In a preferred embodiment of the present invention, the sludge deep dewatering equipment is configured to continuously and integrally dewater the initial sludge to a moisture content of 60%–70%, preferably, for example, a high-pressure belt integrated sludge deep dewatering equipment. Plate and frame filter presses also belong to the category of sludge deep dewatering equipment, but they operate intermittently and have a low degree of automation.

[0013] According to this invention, the auxiliary material has a diversion function. After a layer of auxiliary material adheres to the surface of the sludge particles to be dried, it can form water-permeable channels, which can quickly divert water from the outside of the sludge particles and water from the inside of the particles that is subsequently filtered out from the inside of the sludge particles, thereby achieving the purpose of rapid mechanical drying. Optionally, the auxiliary material can be non-water-soluble solid powder waste and / or biomass waste. Optionally, the non-water-soluble solid powder waste can be one or more of wood ash, biochar, fly ash, and sludge incineration residue. Depending on the back-end disposal method of the sludge, different materials of auxiliary materials can be selected. For example, if the back-end disposal method is incineration, biomass waste such as sawdust or leaves from street sweepings can be added to increase the calorific value of the sludge. Biochar, fly ash, and sludge incineration residue after sludge carbonization can also be used. For another example, if the back-end disposal method is aerobic composting, wood ash can be added to supplement potassium fertilizer, thereby achieving comprehensive resource utilization of waste.

[0014] According to this utility model, the sludge mechanical drying equipment belongs to physical pressing, which is a pure mechanical pressing method powered by, for example, a hydraulic system. It can dry sludge with a moisture content of 60% to 70% to the degree required for the sludge post-disposal method, such as usually below 40% moisture content. Moreover, in the process of operation, apart from the power consumption of the equipment itself, there is no need to rely on a large amount of auxiliary heat source to dry the sludge.

[0015] According to this invention, the slow increase in working pressure in the sludge mechanical drying equipment can be a continuous slow increase in working pressure, or it can be a gradual increase of multiple set pressure values. In a preferred embodiment of this invention, the slow increase in working pressure means that after each set pressure value is reached, the pressure is held for 1-3 minutes, and after this holding operation, the next pressure stage begins. Further, in a preferred embodiment of this invention, one of the set pressure values ​​in each stage is 1.5 MPa / cm².

[0016] In a preferred embodiment of the present invention, the preferred pressure range of the maximum set pressure of the working pressure is greater than 1.5 MPa / cm^2 and up to 2.8 MPa / cm^2 (i.e., the preferred pressure range is 1.5-2.8 MPa / cm^2, but not including 1.5 MPa / cm^2). More preferably, the pressure range is 2-2.8 MPa / cm^2, so as to achieve a sludge drying effect with a lower working pressure that is not significantly different from that under a higher working pressure, thereby further reducing energy consumption.

[0017] In a preferred embodiment of the present invention, corresponding to the aforementioned integrated continuous operation sludge deep dewatering equipment, the sludge mechanical drying equipment is configured to operate intermittently in batches, and a material storage tank is provided between the sludge deep dewatering equipment and the sludge mechanical drying equipment. The initial continuous sludge processing capacity of the sludge deep dewatering equipment, the storage capacity of the material storage tank, and the single processing capacity of the intermittent operation of the sludge mechanical drying equipment are matched to achieve the effect of overall continuous operation.

[0018] In a preferred embodiment of the present invention, the auxiliary material storage and addition device is provided with a control module configured to control the addition ratio of the auxiliary material, and a flow detection module configured to detect the addition ratio.

[0019] The sludge room temperature mechanical drying method and system of this utility model achieve the following beneficial effects:

[0020] 1. The two-stage ambient temperature sludge dewatering and mechanical drying system of this utility model can significantly reduce the moisture content of the sludge after deep dewatering through mechanical drying during the sludge drying stage;

[0021] 2. Compared with existing drying processes that require a large amount of auxiliary heat source, this two-stage ambient temperature sludge dewatering and mechanical drying system achieves mechanical drying of the sludge to be dried without the need for a heat source, resulting in low energy consumption and simple and efficient operation.

[0022] 3. By selecting the appropriate working pressure, the moisture content of the dried sludge can be adjusted and controlled according to different requirements of downstream sludge disposal during the drying process, making the process more flexible and convenient.

[0023] 4. Furthermore, this two-stage ambient temperature sludge dewatering and mechanical drying system can operate fully automatically 24 hours a day without human intervention, is odorless, and reduces deodorization costs. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the two-stage ambient temperature sludge dewatering and mechanical drying system according to the present invention.

[0025] Among them, 1-sludge pump, 2-fully automatic dosing tank, 3-sludge deep dewatering equipment, 4-sludge conveying device, 5-sludge mechanical drying equipment, 6-conditioning tank, 7-auxiliary material storage and addition device, 8-crushing device, 9-sludge transport vehicle. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this utility model clearer, the following detailed description of the two-stage ambient temperature sludge dewatering and mechanical drying system of this utility model is provided through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are merely illustrative of this utility model and are not intended to limit its scope.

[0027] Figure 1 This invention illustrates a two-stage ambient temperature sludge dewatering and mechanical drying system. The system comprises, sequentially from the initial sludge inlet to the dried sludge outlet, a sludge pump 1, a fully automatic dosing tank 2, a conditioning tank 6, a deep sludge dewatering device 3, an auxiliary material storage and addition device 7, a sludge conveying device 4, a crushing device 8, a sludge mechanical drying device 5, and a sludge transport vehicle 9. The sludge pump 1, the fully automatic dosing tank 2, the conditioning tank 6, and the deep sludge dewatering device 3 constitute the deep sludge dewatering stage, while the auxiliary material storage and addition device 7, the sludge conveying device 4, the crushing device 8, and the sludge mechanical drying device 5 constitute the mechanical sludge drying stage.

[0028] According to this utility model, the term "system" refers to an organic whole with specific functions, composed of several interacting components. Therefore, it should be understood that the two sections of the system according to this utility model—the sludge deep dewatering process section and the sludge mechanical drying process section—can be physically separated into different locations, or, as... Figure 1 As shown, they are placed together in the same site to form an integrated sludge treatment system. This physical spatial arrangement does not affect the composition of the "system" according to this utility model.

[0029] In the sludge mechanical drying process section, the auxiliary material storage and addition device 7 is configured to store auxiliary materials with a guiding effect and add the auxiliary materials, with a weight of 3-10% of the weight of the sludge to be dried, to the sludge to be dried. The auxiliary material storage and addition device 7 includes a control module configured to control the addition ratio of the auxiliary materials, and a flow detection module configured to detect the addition ratio, so as to control the weight of the added auxiliary materials.

[0030] The sludge conveying device 4 connects the outlet of the sludge deep dewatering equipment 3 and the crushing device 8, as well as the outlet of the sludge mechanical drying equipment 5 and the sludge transport vehicle 9. It conveys the sludge to be dried during the mechanical drying stage, and after the sludge to be dried is initially mixed with auxiliary materials with a guiding effect at a weight of 3-10% of the sludge to be dried, it is conveyed to the crushing device 8. After the mechanical drying of the sludge is completed, the dried sludge is conveyed to the sludge transport vehicle 9.

[0031] exist Figure 1In the illustrated embodiment, the crushing device 8 is positioned above the sludge mechanical drying equipment 5, enabling further and thorough mixing of the sludge to be dried and the auxiliary materials through agitation and crushing. Preferably, a material storage tank (not shown in the figure) is also provided between the crushing device 8 and the sludge mechanical drying equipment 5. During the intermittent operation of the sludge mechanical drying equipment, the material storage tank can temporarily store the mixture of sludge to be dried and auxiliary materials that has been thoroughly mixed by the crushing device 8 and loaded into it, and during the operation of the sludge mechanical drying equipment, the temporarily stored mixture of sludge to be dried and auxiliary materials is fed into the sludge mechanical drying equipment 5.

[0032] You should know, Figure 1 This illustration only shows one possible arrangement of the pulverizing device 8 and the material storage tank according to the present invention between the sludge deep dewatering equipment 3 and the sludge mechanical drying equipment 5. Those skilled in the art can choose the appropriate arrangement based on actual needs. For example, the pulverizing device 8 and the material storage tank can be arranged independently or in combination. In the case of a combined arrangement, the pulverizing device 8 and the material storage tank can be arranged independently of the sludge mechanical drying equipment 5 and connected to it via the sludge conveying device 4, or they can be combined with the sludge mechanical drying equipment 5.

[0033] As mentioned above, the sludge to be dried after being treated by the sludge deep dewatering equipment 2 can be, but is not limited to, sludge with a moisture content of 60-70%. The sludge to be dried is granular and has certain solid characteristics. When mixed and pressed with the auxiliary material, the sludge to be dried can be better solidified and shaped.

[0034] The term "sludge deep dewatering equipment 2" refers to a general term for dewatering equipment that dewaters initial sludge to 60%-70%, and can include plate and frame filter presses, high-pressure belt presses, etc. In a preferred embodiment of this utility model, the sludge deep dewatering equipment is configured to continuously and integrally dewater the initial sludge to a moisture content of 60%-70%, preferably, for example, a high-pressure belt integrated sludge deep dewatering equipment.

[0035] Figure 1 In the illustrated embodiment, the sludge mechanical drying equipment 5 is a top-feed sludge filter press powered by a hydraulic system, capable of mechanically drying sludge with a moisture content of 60% to 70% to the degree required for subsequent sludge disposal, such as typically below 40% moisture content.

[0036] Corresponding to the aforementioned integrated and continuously operating sludge deep dewatering equipment 2, the sludge mechanical drying equipment 5 operates intermittently in batches. By matching the initial continuous sludge processing capacity of the sludge deep dewatering equipment 3, the storage capacity of the material storage tank, and the intermittent single-cycle processing capacity of the sludge mechanical drying equipment 5, the overall integrated and continuous operation of the system is achieved. Example 1

[0037] In this embodiment, the initial sludge is deeply dewatered and mechanically dried at room temperature using the two-stage ambient temperature sludge dewatering and mechanical drying system according to this invention, reducing the sludge moisture content to approximately 40% for subsequent incineration. The specific operation process is as follows:

[0038] In the sludge deep dewatering process section (i.e., section 1) of this system, the initial sludge with a moisture content of 96% to 98% is continuously pumped from the gravity thickener to the sludge deep dewatering equipment 3 via sludge pump 1. At the same time, the conditioning agent prepared by the fully automatic dosing tank 2 is delivered to the conditioning tank 6 via the dosing pump and fully mixed with the sludge. Then, the conditioning sludge is dewatered to a moisture content of about 85% by the thickener and dewatering machine. Then, iron salt is added and mixed, and the sludge is continuously dewatered to a moisture content of 60% to 70% by the belt filter press (i.e., sludge deep dewatering equipment 3). The iron salt has two functions: first, to neutralize the negative charge of the sludge and reduce electrostatic repulsion; second, to catalyze the degradation of PAM, reduce its water-binding properties, and facilitate the squeezing out of the water between the sludge particles, thus achieving the purpose of deep dewatering.

[0039] In the sludge mechanical drying process section (i.e., the second stage) of this system, sawdust, weighing 5%-10% of the sludge weight, is added to the deeply dewatered sludge to be dried via the auxiliary material storage and addition device 7. The sludge to be dried is then thoroughly mixed with the sawdust via a sludge scraper conveyor (i.e., sludge conveying device 4) and a crushing device 8, and then fed into the sludge mechanical drying equipment 5 for pressure filtration. Within the set pressure filtration time (the specific time can be selected as needed), the working pressure is slowly increased from the initial pressure of 0.45 MPa / cm^2. At the same time, the pressure is held for 1-3 minutes after each set pressure value is reached. After the pressure holding is completed, the next pressure stage begins. One of the set pressure values ​​is 1.5 MPa / cm^2, until the pressure reaches the maximum set pressure of about 2.5 MPa / cm^2, reducing the moisture content of the dried sludge to about 40%. After mechanical drying, the dried sludge is loaded into sludge transport vehicle 9 via sludge conveying device 4 and transported to the downstream treatment site for incineration.

[0040] In this embodiment, the first-stage sludge deep dewatering equipment 3 continuously discharges sludge, while the second-stage sludge mechanical drying equipment 5 operates intermittently in batches, with each batch lasting approximately 20-30 minutes. A material storage box installed on the second-stage sludge mechanical drying equipment 5 can temporarily store materials for 20-30 minutes. The continuous processing capacity of the first-stage sludge deep dewatering equipment 3, the storage capacity of the material storage box, and the intermittent single-batch processing capacity of the second-stage sludge mechanical drying equipment 5 are matched to achieve an overall continuous operation effect. Example 2

[0041] In this embodiment, the initial sludge is deeply dewatered and mechanically dried at room temperature using the two-stage ambient temperature sludge dewatering and mechanical drying system according to this invention, reducing the sludge moisture content to approximately 55%-60% for subsequent composting. The specific operation process is as follows:

[0042] In the sludge deep dewatering process section (i.e., the first stage) of the system, the sludge tank continuously pumps the initial sludge with a moisture content of 96% to 98% from the gravity thickener to the sludge deep dewatering equipment 3 in the first stage via sludge pump 1. At the same time, the conditioner prepared by the fully automatic dosing tank 2 is delivered to the conditioning tank 6 via the dosing pump and fully mixed with the sludge. Then, the conditioned sludge is dewatered to about 85% by the thickener and dewatering machine. Then, iron salt is added and mixed, and the sludge is continuously dewatered to 65% to 70% by the belt filter press, thus completing the deep dewatering of the sludge.

[0043] In the mechanical drying process section (stage two) of this system, 3%-5% by weight of wood ash is added to the deeply dewatered sludge to be dried via the auxiliary material storage and addition device 7. The dried sludge and wood ash are thoroughly mixed by the sludge scraper conveyor and crushing device 8, and then transported to the mechanical drying equipment 5 in stage two for pressure filtration. During the set pressure filtration time, the working pressure is slowly increased from an initial pressure of 0.45 MPa / cm², and pressure is maintained for 1-3 minutes after each set pressure value is reached. After the pressure holding period, the next pressure stage begins, with one stage set at 1.5 MPa / cm², until the pressure reaches the maximum set pressure of approximately 2 MPa / cm². The moisture content of the dried sludge is controlled at approximately 55%-60%. After mechanical drying, the dried sludge is loaded into sludge transport vehicles 9 via the sludge conveying device 4 and transported to the downstream processing site for composting.

[0044] In this embodiment, the first-stage sludge deep dewatering equipment 3 continuously discharges sludge, while the second-stage sludge mechanical drying equipment 5 operates intermittently in batches, with each batch lasting approximately 10-20 minutes. A material storage box located on the second-stage sludge mechanical drying equipment 5 can temporarily store materials for 10-20 minutes. The continuous processing capacity of the first-stage sludge deep dewatering equipment 3, the storage capacity of the material storage box, and the intermittent single-batch processing capacity of the second-stage sludge mechanical drying equipment 5 are matched to achieve an overall continuous operation effect.

[0045] Example 3

[0046] In this embodiment, based on the above embodiment 2, the maximum set pressure value of the working pressure in the sludge mechanical drying equipment 4 in step two is changed (as shown in Table 1 below) to show how the maximum set pressure value adjusts and controls the moisture content of the mechanically dried sludge.

[0047] Table 1: Comparison of pressure per unit area:

[0048] Serial Number Unit pressure MPa / cm^2 Moisture content of dried sludge 1 2 55%-60% 2 2.5 40%-45% 3 2.8 38%-45%

[0049] As shown in Table 1 above, the moisture content of mechanically dried sludge can be adjusted by regulating the maximum set pressure. The pressure value of 2.8 MPa / cm² is the preferred maximum set pressure from the perspective of system energy saving and consumption reduction. This is because, during the experiment, it was found that when the maximum set pressure was adjusted from 2.5 MPa / cm² to 2.8 MPa / cm², the change in sludge moisture content was only 2%. Increasing the pressure to above 2.8 MPa / cm² improved the sludge drying effect somewhat, but not significantly.

[0050] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0051] The embodiments described above are merely illustrative of several implementations of this utility model, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of this utility model patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical concept of this utility model, and these all fall within the protection scope of this utility model. Therefore, the protection scope of this utility model patent should be determined by the appended claims.

Claims

1. A two-stage ambient temperature sludge dewatering and mechanical drying system, characterized in that, It should include, in at least the following order: sludge deep dewatering equipment, auxiliary material storage and addition device, mixing device, and sludge mechanical drying equipment. The sludge deep dewatering equipment is configured to deeply dewater the initial sludge into sludge awaiting drying. The auxiliary material storage and addition device is configured to store auxiliary materials with a diversion function and add auxiliary materials weighing 3-10% of the weight of the sludge to be dried into the sludge to be dried. The mixing device includes at least a sludge conveying device, which is configured to mix the sludge to be dried with added auxiliary materials and convey it to the downstream sludge mechanical drying equipment. The sludge mechanical drying equipment is configured to perform pressure filtration on the mixture of sludge to be dried and auxiliary materials that has been treated by the mixing device. Within the set filtration time, the working pressure is slowly increased from the initial pressure until the pressure reaches the maximum set pressure, which is at least greater than 1.5 MPa / cm^2.

2. The two-stage ambient temperature sludge dewatering and mechanical drying system according to claim 1, characterized in that, The mixing device also includes a crushing device, which is disposed between the sludge conveying device and the sludge mechanical drying equipment, and is configured to further and fully mix the sludge to be dried with the auxiliary materials by stirring and crushing.

3. The two-stage ambient temperature sludge dewatering and mechanical drying system according to claim 1, characterized in that, The sludge to be dried is granular and has solid characteristics. When it is mixed and pressed with the auxiliary materials, the sludge to be dried can be better solidified and shaped.

4. The two-stage ambient temperature sludge dewatering and mechanical drying system according to claim 3, characterized in that, The moisture content of the sludge to be dried is 60-70%.

5. The two-stage ambient temperature sludge dewatering and mechanical drying system according to claim 1, characterized in that, The auxiliary materials are non-water-soluble solid powder waste and / or biomass waste.

6. The two-stage ambient temperature sludge dewatering and mechanical drying system according to claim 5, characterized in that, The non-water-soluble solid powder waste is one or more of the following: wood ash, biochar, fly ash, and sludge incineration residue.

7. The two-stage ambient temperature sludge dewatering and mechanical drying system according to claim 1, characterized in that, The maximum set pressure range is 2-2.8 MPa / cm^2.

8. The two-stage ambient temperature sludge dewatering and mechanical drying system according to claim 1, characterized in that, The sludge deep dewatering equipment is configured to operate continuously as an integrated unit.

9. The two-stage ambient temperature sludge dewatering and mechanical drying system according to claim 8, characterized in that, The sludge mechanical drying equipment is configured to operate intermittently in batches, and a material storage tank is provided between the sludge deep dewatering equipment and the sludge mechanical drying equipment. The initial continuous sludge processing capacity of the sludge deep dewatering equipment, the storage capacity of the material storage tank, and the single processing capacity of the intermittent operation of the sludge mechanical drying equipment are matched to achieve the effect of continuous overall operation.

10. The two-stage ambient temperature sludge dewatering and mechanical drying system according to claim 1, characterized in that, The auxiliary material storage and addition device is equipped with a control module configured to control the addition ratio of the auxiliary material, and a flow detection module configured to detect the addition ratio.

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