Desilting construction method for settling pond for domestic sewage and sewage treatment of coal cleaning plant

Abstract

The invention belongs to the technical field of sewage and sludge treatment, and discloses a sedimentation tank desilting construction method for domestic sewage and coal cleaning plant sewage treatment. The problems that an existing desilting technology is low in efficiency and serious in pollution, and a pool body is damaged are solved. The method comprises the following steps: collecting data, combining a sonar technology to obtain sludge parameters of a sedimentation tank, and formulating a scheme; building a closed operation shed and mounting matched ventilation and purification equipment on a portal frame; adding a composite flocculant, and stirring to precipitate the sludge; discharging clean water; performing microwave pretreatment on the hardened sludge surface, and performing normal-pressure cleaning to form flowing slurry; pumping the flocculating constituent and the slurry, and carrying out gravity concentration and filter pressing dehydration to form a mud cake; a biological conditioner is sprayed after the sedimentation tank is cleaned, and secondary cleaning is conducted; checking and repairing the tank body and spraying a nano anti-corrosion coating; and dismounting the equipment and recovering the site after acceptance. The first-time dynamic microwave treatment is matched with normal-pressure cleaning, biochemical synergy and anti-corrosion technologies, so that the dredging efficiency is improved, the environmental pollution is reduced, and the service life of the pool body is prolonged.

Description

Technical Field

[0001] The invention belongs to the technical field of sewage sludge treatment, and in particular relates to a sedimentation tank desilting construction method for treating domestic sewage and coal washing plant sewage. Background Art

[0002] In the early days, sedimentation tank desilting primarily relied on workers entering the tanks and using simple tools like shovels and buckets to dig and clean. However, sedimentation tanks are confined spaces, potentially prone to oxygen depletion and the accumulation of toxic and hazardous gases. This exposed workers to safety hazards such as poisoning and suffocation. While flexible, this method was extremely inefficient, labor-intensive, and presented significant health risks to workers dealing with sludge containing toxic and hazardous substances.

[0003] Currently, the industry's primary dredging technologies are mechanical, chemical, and biological dredging. Mechanical dredging is further divided into mechanical excavation and vacuum dredging. Mechanical excavation primarily uses large machinery such as excavators and loaders to directly enter sedimentation tanks, scoop out sludge, and load it onto trucks for transport. This method can quickly remove large amounts of sludge from large, thickly accumulated sedimentation tanks in coal washeries. However, the excavation process can easily damage the bottom and walls of the sedimentation tank, and mechanical equipment is difficult to use in confined or complex tanks. Vacuum dredging involves first flushing the sludge within the sedimentation tank using a high-pressure water jet. Then, vacuum equipment creates negative pressure, drawing the sludge into a pipeline and transporting it to a designated location. This method is commonly used in areas with high environmental requirements, such as sewage sedimentation tanks near residential areas. Therefore, this method is suitable for treating thinner sludge. However, the flushed sludge has a high water content, making subsequent treatment more difficult. Similarly, high-pressure water jets can easily damage the hardened layer at the bottom of the sedimentation tank, potentially damaging the tank structure. Chemical desilting often adds flocculants to the sewage in the sedimentation tank to aggregate suspended particles and impurities into larger flocs, accelerating the sedimentation process. The settled sludge is then cleaned. Other methods use strong oxidants to oxidize and decompose organic matter in the sludge, reducing its contamination level and making it easier to clean and subsequently treat. This has been effective for coal washing plant sludge containing large amounts of recalcitrant organic matter. However, during chemical desilting, both the addition of flocculants and strong oxidants can cause secondary contamination, necessitating subsequent final cleanup using methods such as mechanical excavation or vacuum suction. Furthermore, poorly controlled addition not only increases treatment costs but can also have long-term negative environmental impacts. Microbial desilting involves introducing specialized microbial communities into the sedimentation tank. These microorganisms thrive in favorable environments and, through their metabolic activities, decompose organic matter in the sludge, converting it into harmless carbon dioxide, water, and simple inorganic compounds. However, the growth and reproduction of microorganisms have very stringent requirements on environmental conditions, the dredging cycle is long, the effect is slow, and the decomposition effect on different types of organic matter varies significantly.

[0004] In summary, the initial water content of sludge from both coal washeries and domestic sewage sedimentation tanks is very high. This high water content not only makes transportation difficult but also increases the difficulty and cost of subsequent treatment. Existing sludge dewatering technologies, such as mechanical dewatering, can reduce the sludge's water content to a certain extent. However, for some highly hydrophilic domestic sewage sludge, the dewatering effect is less than ideal, making it difficult to meet the requirements for subsequent disposal or resource utilization. Existing dredging equipment often struggles to fully adapt to various complex working conditions. For example, some small domestic sewage sedimentation tanks are cramped, making large mechanical dredging equipment inaccessible. This is especially true in the high-pH sewage environment of coal washeries. This results in high equipment maintenance costs, increasing the overall cost of dredging.

[0005] There are two main types of microwave sludge treatment technologies currently available: First, patent application number CN201510678717.6 discloses a sludge microwave drying method. This method combines heat treatment with microwave treatment through the steps of mechanical dehydration, mixing sludge dry powder, shape control, preheating, microwave pyrolysis, and cooling. This method can reduce the moisture content of the sludge and has the advantage of low energy consumption. Second, patent application number CN201410006127.4 discloses a microwave treatment technology for sewage sludge. This technology first dehydrates the sludge, then adds additives such as polar single crystal silicon ultrafine powder, sintering it in a microwave oven, and then undergoes a series of temperature-controlled calcinations to obtain the sintered material, achieving energy conservation and emission reduction. The above-mentioned disclosed technology mainly uses the principle of microwave pyrolysis to reduce the moisture content of the sludge during the subsequent dehydration treatment of the sludge, thereby reducing the overall treatment energy consumption.

[0006] In view of the complex working conditions of different sedimentation tanks, the key is how to comprehensively consider the structural characteristics of the sedimentation tank, the properties of the silt, the surrounding environment and other factors to achieve non-destructive treatment of the silt and improve the dredging technology with wide applicability and high efficiency. Summary of the Invention

[0007] In response to the dredging problem under complex working conditions, based on years of construction experience and combined with existing sludge treatment technology, we have proposed an efficient dredging technology for the actual conditions of different pool types and sludge properties. This technology mainly adopts the following measures: First, based on the gantry supporting equipment, dynamic microwave treatment technology is introduced for the first time to treat the hardened layer of sludge, and at the same time, normal pressure flushing is used to reduce the damage to the sedimentation tank structure caused by high-pressure flushing during dredging; second, biological agents are selected to replace part of the chemical agents by calculating the sewage treatment volume and sludge removal volume, and the dosage is accurately controlled to reduce the risk of secondary pollution; third, vacuum sludge dredging is combined with the existing chemical dredging technology in staged construction to optimize the dredging process and improve efficiency; fourth, microorganisms such as biological conditioners are used to decompose and clean to remove residual dirt and mud, reduce the use of chemical agents, and reduce the environmental burden; fifth, the sedimentation tank is subsequently repaired and anti-corrosion treated to ensure the long-term stability of the tank structure. In this regard, the present invention provides a dredging construction method for sedimentation tanks for domestic sewage and coal washing plant sewage treatment.

[0008] To achieve the above object, the present invention adopts the following technical solution: a sedimentation tank desilting construction method for treating domestic sewage and coal washing plant sewage, which comprises the following steps: Step 1: Conduct an on-site survey of the sedimentation tank, collect design information and real-time sewage level data, obtain silt thickness and distribution area data, calculate sewage treatment capacity and silt removal volume, and formulate a dredging plan; Step 2: Build an enclosed work shed and equip it with ventilation and air purification equipment to create a closed working environment. Simultaneously, install a gantry and work platform that can move horizontally and vertically in the enclosed work shed. Install microwave radiation equipment, stirring equipment, cleaning equipment, and spraying equipment on the work platform according to the needs of the dredging operation to facilitate multi-angle and all-round dredging operations. Step 3: Add composite flocculant to the sedimentation tank according to the sewage treatment volume, start the stirring equipment to stir, and make the sludge flocculate and settle; Step 4: Use the drainage pump to drain the upper layer of clear water in the sedimentation tank to the nearby sewage collection tank, and then start the mud pump to pump the lower layer of flocculent matter out of the sedimentation tank until the hardened sludge surface is exposed; Step 5: Use a microwave radiation device to pre-treat the surface of the hardened sludge to induce a network of thermal stress cracks in the hardened layer, and then use a cleaning device to flush it to form a flowing sludge; Step 6: Use a mud pump to pump the mud out of the sedimentation tank. The flocculent and sludge are sequentially concentrated by gravity, dehydrated by a belt filter press, and then by a plate and frame filter press to form a mud cake. Step 7: After the sludge is cleaned, use the cleaning equipment to clean the wall and bottom of the sedimentation tank to remove the residual dirt, continue to start the mud pump to pump the mud produced by cleaning to the mud tank truck again, then spray the biological conditioner to enzymatically hydrolyze the residual organic matter, use the cleaning equipment again to clean the sedimentation tank for the second time, and use the mud pump to pump the mud produced by the second cleaning to the mud tank truck to ensure that the environment in the sedimentation tank is completely purified; Step 8: Check the sedimentation tank wall and bottom for damage. If so, repair them. Otherwise, proceed directly to step 9: Step 9: Spray nano-ceramic anti-corrosion coating on the inner wall of the sedimentation tank for anti-corrosion treatment; Step 10: After the project is accepted, dismantle the enclosed work shed and supporting equipment, clean up the site, restore it to its original state, and put it into use.

[0009] Furthermore, in step 1, the silt thickness and distribution area data are obtained by the following method: Step 1.1: Use a multi-beam sonar detector to scan the bottom of the sedimentation tank, and simultaneously use a laser turbidity meter or fluorescence sensor to obtain the physical and chemical characteristics of the sludge surface; Step 1.2: Use geographic information system software to fuse sonar echo data and texture features to generate a three-dimensional silt thickness model and mark the silt distribution area; Step 1.3: For areas with abnormal sonar data, collect silt column samples using a gravity sampler, test the moisture content, particle size distribution, and shear strength, and revise the data model.

[0010] Furthermore, in step 1, the calculation formula for the sludge removal amount is as follows: , Where, r is the silt density, and the value range of domestic sewage silt is 1.05-1.3t / m 3 The value range of coal washing plant sewage sludge is 1.2-1.5t / m 3 ; w is the moisture content of sludge, which is tested by drying method and the value range is 60%-90%; e is the loss rate during sludge removal; V s The actual volume of sludge removed; The calculation formula for sewage treatment capacity is as follows: ; in, A is the bottom area of the sedimentation tank, H 0 is the sewage level before desilting; H 1 is the water level after pumping; The actual sludge removal volume is calculated by the following formula: , Where, A i For sedimentation tank i The area of the desilting zone, h i No. i Average silt thickness in each zone, n is the total number of dredging zones.

[0011] Furthermore, in step 3, the composite flocculant is added through a metering pump, and after the addition, a submersible mixer is started to fully mix the flocculant and the sewage to form stable flocs.

[0012] Furthermore, in step 5, the microwave radiation device uses a microwave generator to dynamically adjust the radiation power and movement trajectory according to the real-time acquired silt thickness data, so that the microwaves evenly cover the surface of the hardened silt.

[0013] Furthermore, the radiation power of the microwave radiation device is dynamically adjusted by: Microwave generator output power , Where: P 0 It is the basic power, ranging from 50-100kW, determined by the sedimentation tank design parameters; k is the power correction coefficient, with a value of 0.1-0.3, which mainly reflects the energy compensation efficiency of the microwave generator for silts of different hardness and is negatively correlated with the organic matter content of the silt; h i For the i zonal silt thickness; t i For the i Zonal silt shear strength; A i / A For the i The proportion of the partition area reflects the weight of the power demand of different hardness areas; The movement trajectory of the microwave radiation device is dynamically adjusted by: Lateral movement speed , Where: u x is the lateral moving speed, the design value range is 0.5-2m / min; u 0 The horizontal reference speed is 1m / min by default; max( t i ) is the maximum shear strength of the partition; tavg is the average shear strength of the desilting area; when the difference in silt hardness is greater, the lateral movement speed is slower, which can ensure the uniformity of microwave coverage in areas with different hardness; Vertical movement speed , u y is the longitudinal moving speed, the design value range is 0.2-1.0m / min; The longitudinal reference speed is 0.6m / min by default; when the silt shear strength of the partition is t i The higher it is, the slower the longitudinal movement speed is, and it is necessary to increase the microwave action time on the hardened sludge; when t i> 2 t avg When the gantry's supporting controller is pressed u y =0.4 implement.

[0014] Furthermore, in step 6, the inlet side of the mud pump pipe is connected to the metal hose through a three-way joint and communicated with the air outlet of the hollow fiber membrane aeration device, and micro-nano bubbles are injected and mixed with the mud by the spiral blades of the mud pump, so that the mud forms a vortex state to reduce the transportation resistance.

[0015] Furthermore, in step 6, a bio-enzyme compound conditioner is added through a metering pump before feeding the belt filter press. The bio-enzyme compound conditioner and the micro-nano bubbles synergistically decompose organic matter in the sludge, thereby improving the sludge dewatering efficiency.

[0016] Furthermore, in step 7, the biological conditioner is evenly sprayed onto the surface of the sedimentation tank using a spraying device to ensure comprehensive coverage and promote uniform degradation of sludge.

[0017] Furthermore, in step 8, the nano-ceramic anti-corrosion coating is evenly sprayed onto the inner wall of the sedimentation tank using a spraying device to enhance the corrosion resistance of the tank body and extend its service life.

[0018] Compared with the prior art, the present invention has the following advantages: The present invention builds a closed work shed and supporting ventilation and air purification equipment, and uses a gantry to remotely control the dredging equipment, freeing manpower from the high-risk environment of a confined space, avoiding contact with toxic and harmful gases and highly polluted sludge, improving construction safety from the root, and reducing labor intensity. It is particularly suitable for sludge treatment scenarios containing complex pollutants.

[0019] This invention introduces microwave pretreatment technology into dredging construction for the first time, using microwave radiation to generate thermal stress cracks in the hardened layer of silt, and combines it with normal pressure flushing to form flowing mud, replacing traditional mechanical excavation and high-pressure flushing. While efficiently breaking up the hardened layer of silt, it minimizes damage to the sedimentation tank structure, solves the dredging problems in narrow spaces and complex pool types, and improves the adaptability of operations under different working conditions.

[0020] Based on the design data of the sedimentation tank and on-site sewage data, the present invention combines sonar scanning and three-dimensional modeling technology to accurately calculate the sewage treatment volume and sludge removal volume, further accurately control the dosage of composite flocculants, and replace some chemical agents with biological conditioning agents, using microbial metabolism to decompose residual organic matter, reducing the risk of secondary pollution caused by excessive use of chemical agents. At the same time, using sludge distribution and physical and chemical data, the control system dynamically adjusts equipment parameters and operation paths to achieve precise control of the dredging process, avoid the blindness of empirical construction, reduce resource waste, improve operational efficiency and stability, and reduce construction costs.

[0021] This method utilizes a three-stage synergistic dehydration process involving gravity concentration, belt filter pressing, and plate and frame filter pressing, combined with a bio-enzyme conditioner to improve sludge dewatering performance. The resulting dry cake is easily transported and disposed of safely. The dry cake maintains a moisture content below 40%, meeting environmental requirements, effectively reducing sludge volume, and lowering subsequent processing costs.

[0022] The present invention adds a biological conditioner to enzymatically hydrolyze residual organic matter during the sedimentation tank dredging process, and also facilitates the subsequent spraying of nano-ceramic anti-corrosion coatings, thereby improving the tank body's tolerance to highly corrosive environments, extending the service life of the facility, and reducing subsequent maintenance costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a flow chart of the sedimentation tank desilting construction method.

[0024] Figure 2 This is a curve diagram of the Zeta potential change under the synergistic effect of the composite flocculant and the bio-enzyme composite conditioner in the present invention.

[0025] Figure 3 This is a graph showing the relationship between the enzyme activity of the bio-enzyme composite conditioner and the concentration of micro-nano bubbles in the present invention.

[0026] Figure 4 This is a diagram showing the change in shear strength of the silt hardened layer in each partition after different microwave treatment methods in the present invention.

[0027] Figure 5 This is a comparison chart of sludge samples treated with different microwave methods in the present invention.

[0028] Figure 6This is a comparison chart of the moisture content changes in the three-stage dehydration of different microwave treatment methods in the present invention.

[0029] Figure 7 This is a relationship diagram between shear strength and breaking efficiency in the microwave dynamic adjustment model of the present invention.

[0030] Figure 8 This is a coupling relationship diagram between the microwave power correction term and the partition parameters in the microwave dynamic adjustment model of the present invention.

[0031] Figure 9 This is a dynamic response relationship diagram between shear strength and microwave movement trajectory in the present invention. DETAILED DESCRIPTION

[0032] In order to further illustrate the technical solution of the present invention, we will further illustrate the present invention through the optimal embodiment according to the specific construction requirements in combination with the actual use in the previous project, on the premise that the specification supports the claims. It should be noted that the specific models of composite flocculants, biological conditioners and bio-enzyme conditioners sold on the market used in the following preferred examples are not the only choice. Therefore, the relevant components and parameters of the agents used refer to the introduction information of the disclosed products and are not described in detail here. Of course, those skilled in the art can verify the optimization scheme of the ratio of different types of composite flocculants, biological conditioners and biological conditioners through multiple tests based on the water quality and sludge characteristics in actual dredging construction, and choose other products with similar performance on the market as substitutes. The same effect can be achieved by adjusting the usage amount. Similarly, the listed equipment models are for reference only and need to be flexibly adjusted in combination with the on-site conditions in actual operation. It is not the only implementation method. If those skilled in the art only replace the equipment model or adjust the agent model or source ratio during construction without changing the entire process flow, it should be regarded as an equivalent implementation method of the present invention.

[0033] As attached Figure 1 As shown, a method for desilting a sedimentation tank for treating domestic sewage and coal washing plant sewage comprises the following steps: Step 1: Conduct an on-site survey of the sedimentation tank, collect the design information of the sedimentation tank and real-time sewage water level data, and obtain the silt thickness and distribution area data. The silt thickness and distribution area data are obtained by the following methods: Step 1.1: Use a multi-beam sonar detector to scan the bottom of the sedimentation tank. While scanning the bottom structure of the sedimentation tank, the distribution of metal components such as steel bars is detected in real time. The detection data is integrated with the sonar 3D model, and microwave radiation-prohibited areas are marked in the GIS system to avoid damage to the sedimentation tank structure. Simultaneously, a laser turbidity meter or fluorescence sensor is used to collect water quality data every hour and draw a corrosive zoning map of the water quality in the tank. If an area with a pH value of less than 6 or a pH value of more than 9 is detected, it is marked as a key area for corrosion prevention. Step 1.2: Use geographic information system software to construct a 3D model of the sedimentation pond and embed it into a machine learning model trained on historical desilting data. This machine learning model uses an LSTM neural network algorithm. This model inputs historical data on sedimentation rates and water quality changes in the sedimentation pond over the past three years, combined with current sonar scan results, to predict the spatial distribution of silt. The model outputs a 3D visualization that includes zoning treatment priorities, marking areas with shear strength greater than 80 kPa and thickness greater than 1.5 m as hard zones and other areas as soft zones. Step 1.3: For areas with abnormal sonar data, gravity sampling is triggered if the thickness measurement error is greater than 5% or the shear strength deviates from the model prediction by greater than 15%. A silt column sample is collected using a gravity sampler. During gravity sampling, the silt at each sampling point is layered and sampled. Each layer is tested for moisture content, particle size distribution, and heavy metal content. Particle size distribution is determined using a laser particle size analyzer, and heavy metal content is measured using an atomic absorption spectrophotometer. The test results are compared and analyzed with the sonar data to correct for interlayer errors in the sonar measurement, ensuring a thickness measurement error of ≤5% and a distribution area identification accuracy of ≥95%.

[0034] On this basis, we further calculated the sewage treatment volume and sludge removal volume. The calculation formula for sludge removal volume is as follows: , where r is the silt density, and the value range of domestic sewage silt is 1.05-1.3t / m 3 The value range of coal washing plant sewage sludge is 1.2-1.5t / m 3 ; w is the moisture content of sludge, which is tested by drying method and the value range is 60%-90%; e The loss rate during the sludge removal process indicates the proportion of sludge loss due to mechanical residue and pipeline adhesion during the sludge removal process. It is calculated based on material balance measurements according to specific working conditions and ranges from 5% to 8%. The upper limit is taken for coal washing plant sludge, and the lower limit is taken for domestic sewage sludge. V s The actual volume of silt removed is calculated through sonar scanning and modeling data. , where A i For sedimentation tank i The area of the desilting zone, h i No. i Average silt thickness in each zone, n is the total number of dredging zones.

[0035] The calculation formula for sewage treatment capacity is as follows: ,in, A is the bottom area of the sedimentation tank, H0 is the sewage level before desilting; H 1 is the water level after pumping; The dosage of composite flocculant is calculated based on the sewage treatment volume, which is 2-3 kg per cubic meter of sewage. The dosage of bio-enzyme composite conditioner is 0.1%-0.3% of the sludge removal volume. The dosage of biological conditioner is calculated based on the surface area of the pool, which is 5-10 L / m 2 The spray path is primarily a single-pass straight-line spraying method, with lateral speeds set at 25-35 cm / s and longitudinal speeds at 15-25 cm / s. The nano-ceramic anti-corrosion coating is applied in a dosage of 2-4 kg / m², with a coating thickness of 150-200 μm. A zigzag reciprocating spray pattern is used, with lateral speeds set at 15-25 cm / s and longitudinal speeds at 8-15 cm / s.

[0036] The radiation power of the microwave radiation device is dynamically adjusted by: , where: P 0 It is the basic power, ranging from 50-100kW, determined by the sedimentation tank design parameters; k is the power correction coefficient, with a value of 0.1-0.3, which mainly reflects the energy compensation efficiency of the microwave generator for silts of different hardness and is negatively correlated with the organic matter content of the silt; h i For the i zonal silt thickness; t i For the i Zonal silt shear strength; A i / A For the i The proportion of the partition area reflects the weight of the power demand of different hardness areas; The movement trajectory of the microwave radiation device is dynamically adjusted by: (1) Horizontal movement speed , Where: u x is the lateral moving speed, the design value range is 0.5-2m / min; u 0 The horizontal reference speed is 1m / min by default; max( t i ) is the maximum shear strength of the partition; t avg is the average shear strength of the desilting area; when the difference in silt hardness is greater, the lateral movement speed is slower, which can ensure the uniformity of microwave coverage in areas with different hardness; (2) Longitudinal movement speed , Where: u y is the longitudinal moving speed, the design value range is 0.2-1.0m / min; The longitudinal reference speed is 0.6m / min by default; when the silt shear strength of the partition is t i The higher it is, the slower the longitudinal movement speed is, and it is necessary to increase the microwave action time on the hardened sludge; when t i> 2 t avg When the gantry's supporting controller is pressed u y =0.4 implement.

[0037] The parameters for regulating radiation power are input into the microwave radiation device's control system. The system automatically adjusts the radiation power based on real-time monitoring of silt thickness and shear strength. Simultaneously, the movement trajectory parameters are input into the gantry's controller. Based on real-time monitoring data, the system dynamically adjusts the horizontal and vertical movement speeds to ensure even microwave radiation coverage of all silt zones, improving dredging efficiency.

[0038] Through the above method, we can accurately calculate the dosage of composite flocculant, the dosage of biological conditioner and bio-enzyme composite conditioner, design the movement path parameters of biological conditioner and nano-ceramic anti-corrosion coating, and accurately control the power and movement trajectory of microwave radiation device, so as to formulate the optimal dredging plan.

[0039] Step 2: Build an enclosed work shed and equip it with ventilation and air purification equipment. Kruger CV series centrifugal fans are used for ventilation. These fans feature an intelligent variable frequency control module that seamlessly connects to the IoT platform via the ModbusTCP protocol, enabling energy optimization and remote operation and maintenance. Honeywell DME series air purification equipment is purchased. This integrated photocatalytic oxidation technology increases PM2.5 removal efficiency to 99.8% and supports AI algorithms to dynamically adjust purification intensity. Temperature and humidity sensors are also installed in the shed to monitor environmental parameters in real time to ensure a stable working environment. Data from all equipment is integrated through the IoT platform, enabling remote monitoring and intelligent scheduling. These supporting equipment create a closed working environment within the enclosed work shed. A gantry is installed within the shed, preferably an Omron CK series gantry equipped with a CK3M motion controller that supports both EtherCAT and Profinet. The motion trajectory parameters for each work process are input into the CK3M motion controller, and data is transmitted in real time via EtherCAT. Furthermore, the gantry's equipped Keyence IV-3000 vision sensor transmits detection data to the CK3M controller via TCP / IP, automatically adjusting power output based on real-time monitoring of silt density, thickness, and gantry movement speed. The work platform is welded from high-strength aluminum alloy. The Omron CK series gantry utilizes dual direct-drive motors and THKSRG series linear guides. The work platform is mounted on the gantry's crossbeam slide, ensuring the gantry precisely follows the preset trajectory, effectively improving operational efficiency and safety. Microwave radiation equipment, stirring equipment, cleaning equipment, and spraying equipment are installed on the work platform according to the needs of the dredging operation. The microwave radiation equipment uses the MW-100kW microwave generator produced by Nanjing Sanle Group, with a power adjustment range of 50-100kW and a frequency of 2450MHz. It uses the ARMCortex-M4 processor and directional coupler to collect power signals in real time, and combines the PID algorithm to achieve continuous adjustment of output power. The calculated and adjusted radiation power parameters can be directly set through the panel buttons or the host computer. It also supports receiving 4-20mA analog signals from the gantry control system and is integrated with the gantry beam through a waveguide interface.

[0040] Step 3: Add a composite flocculant to the sedimentation tank according to the sewage treatment volume. The composite flocculant is preferably purchased from Gongyi Xinqi HM-106 high-efficiency composite flocculant. The composite flocculant is compounded with polyaluminum chloride and polyacrylamide, and has the characteristics of high-efficiency flocculation and rapid sedimentation. It can effectively reduce water turbidity and improve sludge dewatering efficiency. Of course, zwitterionic polyacrylamide AMPAM can also be used instead of HM-106 high-efficiency composite flocculant, which should be regarded as an equivalent choice. It also has excellent flocculation effect and sedimentation performance, and the use scheme can be flexibly adjusted according to actual needs. Therefore, this embodiment is not limited to a single scheme. The above-listed flocculants can be evenly added through a precise metering pump. After addition, start the submersible mixer and stir at a speed of 120-180r / min for 20-30 minutes to ensure that the flocculant and sewage are fully mixed to form stable flocs. It should be noted that the above stirring process requires strict control of stirring time and speed to prevent the flocs from breaking and affecting the subsequent sedimentation effect. After stirring, let it stand for 30-60 minutes until the flocs are fully settled.

[0041] Step 4: Use a drainage pump to drain the upper layer of clear water from the sedimentation tank to a nearby sewage collection tank. Then, start the mud pump to suck the lower layer of flocculent matter out of the sedimentation tank until the hardened sludge surface is exposed. It should be noted that the inlet side of the mud pump pipe is connected to a metal hose via a three-way joint and communicates with the air outlet of the hollow fiber membrane aeration device. The hollow fiber membrane aeration device is purchased from Shanghai Zhongjing, a micro-nano bubble generator model ZJ-NB-2000. It uses Venturi jet and ultrasonic synergistic technology to generate micro-nano bubbles with a particle size of less than 200nm. After the micro-nano bubbles are injected into the pipeline, they are mixed with the mud using the spiral blades of the mud pump, causing the mud to form a vortex state and reduce transportation resistance. The efficient oxidation effect of the micro-nano bubbles can further decompose organic matter in the mud, improve the fluidity of the mud, and ensure a smooth transportation process.

[0042] Step 5: Use a microwave radiation device to perform microwave pretreatment on the surface of the hardened sludge. Since the water, organic matter and minerals in the sludge have different dielectric constants, the microwave energy is preferentially absorbed by the water and polar organic matter, and converted into heat energy, causing the local temperature to rise rapidly, resulting in a difference in thermal expansion coefficient between the high-temperature area and the low-temperature area. When the thermal stress exceeds the tensile strength of the sludge, it induces the formation of a network of thermal stress cracks in the hardened layer. Then, a cleaning equipment is used to flush and form a flowing mud, which cleans the hardened sludge while reducing damage to the sedimentation tank structure. The cleaning equipment is a Hongxing HX-1535 industrial cold water high-pressure cleaning machine. This model of cleaning machine can control the output pressure of the high-pressure plunger pump by rotating the pressure regulating valve to achieve a pressure adjustment of 10-35MPa to ensure the cleaning effect.

[0043] Step 6: The sludge is pumped out of the sedimentation tank using a slurry pump. The flocs and sludge are then dehydrated sequentially through gravity concentration, a belt filter press, and a plate and frame filter press to form a sludge cake. A bio-enzyme compound conditioning agent is added via a metering pump before feeding the belt filter press. A GM series mechanical diaphragm metering pump is used as the metering pump. The bio-enzyme compound conditioning agent synergistically decomposes organic matter in the sludge, improving sludge dewatering efficiency. In this example, the bio-enzyme compound conditioning agent is a commercially available Bacto-Zyme 1011 series bio-complex enzyme. The gravity concentration equipment is a model NZY-15 hydraulic center-drive high-efficiency concentrator, the belt filter press is a model LDFT-2500 split belt filter press, and the plate and frame filter press is a model AZG1000 / 1250-U fully automatic plate and frame filter press. These three components work together to ensure efficient sludge dewatering, ultimately producing dry sludge with a moisture content below 40%, making it easier to transport and dispose of.

[0044] Step 7: After the sludge is cleaned, use a cleaning device to clean the walls and bottom of the sedimentation tank to remove residual dirt, continue to start the mud pump to pump the mud produced by the cleaning to the mud tank truck again, then spray the biological conditioner to enzymatically hydrolyze the residual organic matter, use the cleaning equipment to clean the sedimentation tank again, and use the mud pump to pump the mud produced by the second cleaning to the mud tank truck to ensure that the environment in the sedimentation tank is thoroughly purified; use a spraying device to evenly spray it on the surface of the sedimentation tank, with an interval of at least 24 hours between the two sprayings. In this embodiment, the biological conditioner is Yuebao-COD degrading bacteria, purchased from Henan Yuebao Biotechnology Co., Ltd. The product is composed of Bacillus, Pediococcus and biological enzymes, and can decompose phenols and ketones through the synergistic metabolism of microorganisms.

[0045] Step 8: Check whether the wall and bottom of the sedimentation tank are damaged. If so, use cement mortar to repair them. Otherwise, go directly to step 9: Step 9: After the sedimentation tank and the repair area are dry, spray the inner wall of the sedimentation tank with nano-ceramic anti-corrosion coating for anti-corrosion treatment; the nano-ceramic anti-corrosion coating is model CH-66 heavy-duty anti-corrosion nano-ceramic coating, which is evenly sprayed onto the inner wall of the sedimentation tank using spraying equipment to enhance the corrosion resistance of the tank body and extend its service life.

[0046] Step 10: After the project is accepted, dismantle the enclosed work shed and supporting equipment, clean up the site, restore it to its original state, and put it into use.

[0047] It should be noted that in steps 7 and 9 above, when spraying the inner wall of the sedimentation tank with the biological conditioner and nano-ceramic anti-corrosion coating, the preferred spraying equipment is a GracoX5 air-assisted airless sprayer equipped with a 24D185 high-pressure plunger pump and a G40 air-assisted spray gun. Quick-connect hoses allow for flexible operation. When connecting the pipes, first connect the high-pressure pump outlet to the main delivery pipe, then connect to the paint tank and air compressor respectively through a T-connector to ensure precise mixing of the paint and compressed air within the spray gun. The spray gun mount should be equipped with a laser rangefinder to monitor the distance between the nozzle and the tank wall in real time, automatically adjusting the spray volume and spray angle to ensure uniform coating coverage and avoid spray leaks and accumulation.

[0048] Things to note when using this equipment: ① Before spraying, flush the pipeline with a special cleaning agent for 5 minutes to avoid cross contamination; ② When spraying biological conditioners, use ventilation equipment to maintain the working environment temperature at 15-35°C and humidity <80%, reduce the pump pressure to 50 bar to avoid high pressure destroying microbial activity, set the air flow rate to 15L / min, and control the nozzle to about 40 cm away from the pool wall; ③ When switching to nano-ceramic coating, adjust the pump pressure to 150 bar, thoroughly clean the pipeline with clean water, and construct in a "Z" shaped path. The dry film thickness of a single spray should be controlled at 150μm; ④ After using the equipment, immediately use xylene to reverse flush the pipeline, disassemble the nozzle and soak it in xylene solvent to prevent the paint from drying and clogging. Example 1

[0049] Project 1 is a domestic sewage treatment plant with 6 sedimentation tanks, 4 of which are in use and 2 are spare. The area of each tank is 300m 2 In this experiment, A1 and A2 pools were randomly selected. The initial parameters of the sludge in the two pools were the same: average thickness 1.2m, shear strength 65±2kPa, moisture content 83%±1%, COD concentration 2000±50mg / L, SS concentration 2800±100mg / L. During the construction process, it is necessary to use the working environment control system built with ventilation equipment and purification equipment to control the temperature in the working shed to 22±2℃, humidity 65%±5%, and ventilation volume 2000m 3 / h. At the same time, the air quality in the shed needs to be monitored in real time to ensure that the concentration of harmful gases is below the safety limit. This construction step is mainly to explain the basic construction process in detail according to the actual situation on site. First, collect the construction and operation data of the sedimentation tank, including the structure of the tank body, the history of silt deposition, etc., to assess the difficulty of dredging. Use a multi-beam sonar detector to scan the bottom of the pool, generate a three-dimensional silt model, and locate the distribution of the hardened layer. The multi-beam sonar detector is a Kongsberg EM2040 model with an operating frequency of 200-400kHz and a scanning accuracy of ±0.05m. Then, build a gantry, an operating platform, and a closed work shed and equip them with ventilation equipment and air purification equipment to form the infrastructure required for a closed environment.

[0050] The experimental group began the initial sewage flocculation treatment, adding Gongyi Xinqi HM-106 composite flocculant and stirring with a submersible mixer for 25 minutes. The floc settling rate was 2.3 cm / min, which promoted the rapid flocculation and sedimentation of suspended solids. Subsequently, the sludge pump was started to extract the supernatant and lower the water level in the pool to the designed elevation. According to the requirements of the subsequent dredging process, the Jiangsu Microwave Source MW-6000 microwave generator was installed on the operating platform and moved according to the designed parameters (transverse speed 1 m / min, longitudinal speed 0.6 m / min). The hardened layer was irradiated for 6 minutes / m 2 , inducing thermal stress cracks in the hardened layer. The operating pressure of the Hongxing HX-1535 cleaning machine was then adjusted to 10 MPa, flushing to create a flowing slurry and preventing high-pressure damage to the tank. A slurry pump pumped the flocculent and flowing slurry into a tertiary dewatering system, ultimately forming a mud cake. The equipment operating parameters were as follows: a 3-5 hour retention time in the gravity thickener; a 1-3 m / min filter belt speed and 0.2-0.5 MPa pressure in the plate and frame filter press; and a 1.0-1.5 MPa pressure hold for 20-30 minutes in the belt filter press. Yuebao-COD-degrading bacteria was sprayed, followed by a second cleaning every 24 hours, and the residual COD removal rate was tested. If the test passed, damaged areas on the tank wall were repaired with M15 cement mortar. After drying, a Graco X5 sprayer was used to apply CH-66 nano-ceramic coating to the inner wall of the sedimentation tank to form an anti-corrosion layer. Finally, the closed environment facilities were dismantled, the site was cleaned up, the pool was restored to normal use, construction data was recorded, the dredging effect was evaluated, and long-term stable operation was ensured.

[0051] Control group: Pool A2 used traditional desilting methods, ensuring the same working environment and wastewater treatment conditions. The flocculant type, dosage, and dewatering process were also the same. Steps 7 and 9 were omitted. In step 5, the operating pressure of the Hongxing HX-1535 cleaning machine was set to 25 MPa, directly flushing the hardened silt layer, replacing the microwave treatment plus atmospheric pressure flushing method.

[0052] After desilting, a 3D laser scanner (Leica BLK360) was used to inspect worn areas of the sedimentation tank. COD was measured using the potassium dichromate method specified in HJ828-2017; ammonia nitrogen removal rate was typically determined using Nessler's reagent spectrophotometry. SS concentration was measured using the industry's standard gravimetric method (GB / T11901-1989) to determine suspended solids per unit volume. Aluminum ion concentration in the water was also measured using the ICP-MS method specified in HJ700-2014. See Tables 1 and 2 for a comparison of the desilting results of the two construction methods.

[0053] Table 1: Comparison of damage to sedimentation tank structure and maintenance costs under two construction methods

[0054] Table 2: Comparison of dredging efficiency, environmental protection and cost of two construction methods

[0055] The data in Tables 1 and 2 demonstrate that the proposed construction method offers significant advantages over traditional methods. Regarding both structural damage and protection, the wear depth of the sedimentation tank wall was reduced from 3.2 mm to 0.5 mm, and the number of repair areas was reduced from 27 to 6. Furthermore, the application of a 0.15 mm thick CH-66 nano-ceramic anti-corrosion coating resulted in a two-year corrosion protection cycle with only one annual maintenance visit, compared to four annual maintenance visits for the traditional method without an anti-corrosion coating. Regarding dredging efficiency and cost, despite a delay in the construction cycle due to process differences, flocculant usage was reduced by 50%, and the sludge cake moisture content dropped from 72% to 38%, significantly reducing overall costs compared to the original method. Furthermore, COD residues decreased from 112 mg / L to 48 mg / L, with undetectable aluminum ion levels, compared to 28 mg / kg for the traditional method. SS concentrations decreased by 87.5%, surpassing the control group, demonstrating that the proposed "microwave + chemical synergy" method effectively reduces suspended solids concentrations in water. In summary, the present invention achieves low damage, high efficiency, low pollution and long life in sedimentation tank dredging through microwave pretreatment, biochemical synergy and anti-corrosion coating technology, significantly improving the overall benefits. Example 2

[0056] Project 2 is a coal washing plant with 5 sedimentation tanks, each with a capacity of 2000m 3 It mainly treats wastewater generated by coal preparation, with an annual sludge production of about 120,000 m 3 The traditional "PAC flocculation + centrifugal dehydration" process has numerous issues, including high chemical dosage, high moisture content in the mud cake, and a high risk of heavy metal leaching. Furthermore, the COD removal rate is only 40% to 50%. Before the project commenced, the coal washing plant provided the following wastewater physical and chemical data: a moisture content of 88% to 92%, a viscosity of 5000 cP at 20°C, a COD content of 2200 to 2800 mg / L, containing recalcitrant organic matter such as phenols and polycyclic aromatic hydrocarbons, an ammonia nitrogen concentration of 50 to 80 mg / L, and 60% of the coal slime particles were <0.075 mm.

[0057] Based on the above basic situation, we selected two sedimentation tanks B1 and B2 for the experiment. The experimental working environment and sewage environment of this experiment were consistent with those of Example 1. The experimental group adopted the three-stage dehydration mode of "gravity concentration → belt filter press → plate and frame filter press" of the present invention, combined with the bio-enzyme composite conditioner and micro-nano bubble synergistic treatment process, and added Bacto-Zyme 1011 series bio-complex enzymes according to 0.1%~0.3% of the sludge removal amount. The dissolved oxygen concentration of micro-nano bubbles was maintained at about 30mg / L. The control group only used the same model and amount of flocculant as the experimental group and the three-stage dehydration treatment mode, but without bio-enzyme and micro-nano bubble technology.

[0058] The experimental equipment included a Shanghai Zhongjing ZJ-NB-2000 micro-nano bubble generator and a Büchner funnel apparatus. The following testing methods strictly adhere to national standards and are common industry practices, so they are summarized here: moisture content is determined by the drying method, COD is determined according to the potassium dichromate method (HJ828-2017), ammonia nitrogen removal rate is typically determined using Nessler's reagent spectrophotometry, and aluminum ion removal is determined using ICP-MS. Each indicator was tested three times and the average value was taken to ensure data accuracy. Based on the above experimental test conditions and testing methods, we present a comparative analysis of the key performance data of the two construction processes. The specific experimental results are shown in Table 3.

[0059] Table 3: Comparison of dredging effects and costs of two methods

[0060] From the comparison of the data in Table 3, it can be seen that the present invention uses biological enzymes to decompose extracellular polymers of sludge to reduce viscosity, and micro-nano bubbles carry fine particles to float by flotation and provide high dissolved oxygen to enhance enzyme activity, thereby reducing the specific resistance from 2.56×10 11 m / kg decreased to 1.78×10 11 m / kg, the dehydration efficiency increased by 34%, far exceeding the dehydration effect of traditional processes. Biological enzymes and micro-nano bubbles synergistically promote microbial metabolism, COD removal rate increased from 48% to 82%, ammonia nitrogen removal rate increased from 32% to 78%, and the organic matter degradation effect was significant. Biological enzymes replaced part of the flocculant, and the cost of the agent was reduced from 15 yuan / m 3 Reduced to 8 yuan / m 3 The comprehensive treatment cost is from 82 yuan / m 3 Reduced to 45 yuan / m 3 It can be seen that the present invention achieves a comprehensive improvement in sludge dewatering efficiency, pollution control capability and economic benefits through the synergistic effect of biological enzymes and micro-nano bubbles.

[0061] In Example 2, we measured the zeta potential using a Malvern Zetasizer Nano ZS90 potential analyzer. Specifically, we collected sludge samples from the experimental group before and after adding a composite flocculant, as well as after adding a bio-enzyme composite conditioner. We placed 10 g of the sample in a 100 mL centrifuge tube, diluted it with deionized water to a solid content of 0.1%, and ultrasonically dispersed it for 3 minutes to ensure uniform suspension of the particles. The temperature was controlled at 25 ± 0.5 ° C. Using a constant temperature sample cell, we repeated the measurement three times for each sample, taking the average value as the final result. The background potential of deionized water was then deducted to correct for the actual zeta potential of the sludge particles.

[0062] like Figure 2 As shown, the addition of the composite flocculant increased the zeta potential from -25 mV in the original sludge to -18 mV, and to -12 mV after the addition of the bio-enzyme composite conditioner. This gradual increase in potential indicates that the composite flocculant and bio-enzyme composite conditioner effectively neutralized the negative charge on the surface of the sludge particles, weakened the electrostatic repulsion between the particles, and promoted particle aggregation and flocculation. Furthermore, the positive change in zeta potential corresponds to the treatment stage, indicating that the composite flocculant aggregates particles through charge neutralization and bridging, while the bio-enzyme composite conditioner enzymatically degrades sticky substances, reducing surface charge density. This synergistic effect increases floc size from 0.5 mm to 2.5 mm, increasing settling velocity by 50%. Furthermore, the bio-enzyme composite conditioner partially replaces chemical flocculants, reducing the risk of secondary pollution.

[0063] In Example 2, we selected flocs and sludge as research samples, and prepared bio-enzyme compound conditioners and micro-nano bubble generators. We set up multiple groups of experiments separately, and each group of experiments controlled the concentration of micro-nano bubbles differently, while other conditions remained consistent. The same dose of bio-enzyme compound conditioner was added to the sludge samples in each group of experiments, and then micro-nano bubbles of different concentrations were injected into the sludge samples through the micro-nano bubble generator, and the reaction time after the bubbles were injected was recorded. Within the set time interval, part of the sludge was taken out from each group of samples, and the substrate was labeled with a fluorescent dye, and the activity of the protease was detected by measuring the change in the fluorescence signal. The micro-nano bubble concentration and the corresponding bio-enzyme activity data at different time points in each group of experiments were recorded in detail.

[0064] The experimental results are as follows Figure 3 Comparing the changes in enzyme activity in flocs and sludge samples at different micro-nanobubble concentrations revealed that both showed an initial increase followed by a decrease in enzyme activity with increasing bubble concentration. Due to their loose structure and larger surface area, flocs exhibited higher overall enzyme activity than sludge samples. However, the optimal bubble concentration for both samples was 30 mg / L, at which enzyme activity peaked and the sludge specific resistance was lowest. Above this concentration, floc enzyme activity declined more rapidly, indicating poor tolerance to high bubble concentrations. Example 3

[0065] In the coal washing plant sedimentation tank desilting project of Example 2, key data such as silt partition thickness and shear strength, partition area, and total treatment area were obtained through early multi-beam sonar scanning. We divided the sedimentation tank C into 5 zones according to the silt thickness difference > 0.3m and the shear strength error controlled at ±5kPa. At the same time, the organic matter content of the silt sample in each zone was measured. The specific zoning is shown in Table 4 below. Before construction, the sedimentation tank C was divided into 2 operating units of equal area by building isolation facilities with scaffolding for zoning treatment. Under the premise of ensuring that other construction conditions and application processes remain consistent, after completing the preliminary step 4 desilting pretreatment work, only step 5 uses two different methods to microwave the silt hardening layer. The experimental group adopts the above-mentioned dynamic power adjustment model ( P 0 =80kW, k =0.08) and dynamic adjustment of movement trajectory, the control group used fixed power P =100kW, with a horizontal and vertical movement speed of 0.5m / min. Both groups used a linear reciprocating motion to microwave each section of the individual working unit for 6 minutes. A cleaning machine was then used, maintaining a water pressure of 10MPa. The flushing time was adjusted based on the sludge removal status to ensure thorough flushing of each working unit. A slurry pump then transported the washed sludge to a three-stage dehydration process, consisting of gravity concentration, belt filter press, and plate and frame filter press, to produce a sludge cake. The weight and moisture content of the sludge cakes were recorded for both groups to compare and analyze the effects of microwave treatment on sludge dehydration. After microwave treatment, a gravity sampler was used to collect sludge column samples from each section for shear testing to determine the shear strength. Shear strength changes were recorded. After desilting, a 3D laser scanner was used to inspect the pool bottom for wear. Any damage was repaired, and anti-corrosion treatment was then applied. Desilting efficiency, pool damage, and overall costs, including reagent consumption, equipment wear, and repair materials, were recorded to evaluate the desilting effectiveness of the two different microwave treatments. At the same time, the drying method in GB / T18772-2012 document was used to detect the moisture content of the mud cake at each stage of dehydration treatment, and the effects of two different microwave treatment methods on the dehydration effect of the mud cake were studied.

[0066] Table 4: Silt thickness, shear strength and area ratio data for different zones

[0067] As shown in Table 4, zones 1, 2, and 3 are hard zones, representing the main silt accumulation areas. Silt thicknesses are ≥1.2 m, shear strengths are ≥65 kPa, and organic matter content is high, requiring high-energy microwave treatment for degradation. Zones 4 and 5 are soft zones, with silt thicknesses ≤1.0 m and shear strengths ≤50 kPa, prone to excessive degradation, resulting in energy waste.

[0068] Based on the on-site construction results, we have listed the post-dredging costs for both microwave treatment methods, the tank repair status, and the desilting expenses. Expenditure costs include equipment energy consumption, labor costs, and material consumption. Tank repair status includes the repaired area and material usage, while desilting expenses cover the overall construction costs. See Table 5 for detailed data.

[0069] Table 5: Comparison of costs and repair status of two microwave treatment methods

[0070] The data in Table 5 demonstrates that the dynamic power adjustment method offers superior performance in terms of treatment costs and tank integrity. By dynamically adjusting microwave radiation power and movement trajectory, it avoids wear and cracking on the tank bottom caused by localized energy concentration, effectively protecting the sedimentation tank's durability compared to the control group. Dynamic power adjustment significantly reduces the number of repairs and treatment costs, improves construction efficiency, and reduces tank damage. This demonstrates that the dynamic power model, based on the principle of "differentiated energy demand by zone," reduces excess energy in soft zones, while also reducing repair frequency and equipment loss, ultimately achieving energy savings and cost optimization.

[0071] As attached Figure 4 As shown, before microwave treatment, the shear strength of the sludge in each zone varied significantly, with Zone 1 at 90 kPa and Zone 5 at 45 kPa. After the experimental group adopted a dynamic power adjustment model and dynamic motion trajectory, the shear strength of each zone was significantly reduced: Zone 1 dropped from 90 kPa to 31.0 kPa, a decrease of 65.6%, and Zone 3 dropped from 65 kPa to 29.2 kPa, a decrease of 55.1%. The control group, using a fixed power of 100 kW and a constant speed of 0.5 m / min, saw a smaller decrease in shear strength, with Zone 1 dropping to only 45.0 kPa and Zone 3 to 39.0 kPa.

[0072] like Figure 5 As shown in the figure, two sludge samples were taken from the junction of zones 3 and 4. Figure (a) shows the sludge sample after dynamic power adjustment microwave treatment, and Figure (b) shows the sludge sample after fixed power treatment. Figure (a) shows a clear crack network on the surface of the sludge sample, while Figure (b) shows only a few irregular cracks. This shows that dynamic power adjustment can precisely allocate energy according to sludge hardness, improving the efficiency of hard zone removal by 15% to 25%, solving the problem of "insufficient energy in hard zones and excess energy in soft zones" in fixed power mode.

[0073] like Figure 6As shown, the dynamic power adjustment of the experimental group at each stage of the three-stage dehydration was superior to the fixed power of the control group. Specifically, after gravity concentration, the moisture content of the experimental group dropped from 88% to 65%, while that of the control group dropped to 72%; after belt filter pressing, the moisture content of the experimental group dropped to 45%, while that of the control group dropped to 58%; after plate and frame filter pressing, the moisture content of the mud cake in the experimental group was 34%, while that of the control group was 55%, an increase of 61.8% in meeting environmental protection requirements. This indicates that microwave pretreatment significantly improves dehydration efficiency by destroying the colloidal structure of the sludge, reducing the bound water content, and combining it with bio-enzyme conditioning agents. The mud cake moisture content is 21 percentage points lower than that of the control group. Furthermore, different microwave energies are fully coupled with the organic matter in the sludge, promoting the thermal decomposition of the organic matter and subsequent bio-enzymatic decomposition.

[0074] In the following, combining the interaction mechanism between microwave and sludge, energy demand calculation and working condition adaptability, taking Example 3 as the research sample, we explain the formula derivation process and theory of the power dynamic adjustment model.

[0075] Basic power P 0 It is the minimum energy threshold to maintain the normal operation of microwave radiation equipment, which is directly related to the inherent properties of the sedimentation tank, such as the tank volume and the designed silt removal efficiency. The basic power must meet the energy requirements of heating a unit volume of sludge to the target temperature, reflecting the basic constraint of the tank size on power. Therefore, based on the first law of thermodynamics, its calculation formula is , where: Q is the total volume of sludge in the sedimentation tank, which is determined by the bottom area of the tank. A Average silt thickness h avg OK, that is ; ΔT is the sludge temperature change value, which needs to reach the critical temperature for the formation of thermal stress cracks, usually 60~100℃; c is the specific heat capacity of sludge, ranging from 2.5 to 4.0 kJ / (kg·℃); t It is the microwave radiation time, which is determined by the desilting cycle requirements.

[0076] As attached Figure 7 As shown, t i =90kPa, the decrease is 65.6%, t i =45kPa, the decrease is 60%. This shows that the shear strength is positively correlated with the decrease, proving that dynamic adjustment allows the hard zone to obtain more energy. On the contrary, under the fixed power of the control group, the decrease is t i Increase and decrease ( t i=90kPa, only 50%), exposing the defect of "insufficient energy in the hard zone". Therefore, the energy demand for a single zone is proportional to the energy required to break the hardened sludge, the thickness, and the shear strength, that is: It can be seen that the energy demand for breaking hardened sludge increases significantly with the increase of thickness and shear strength. The partition power correction item needs to accurately reflect this characteristic to ensure that microwave energy acts efficiently on each partition to achieve uniform breaking.

[0077] As attached Figure 8 As shown in Figure 2, the thickness, shear strength and area ratio of silt in different partitions are significantly different, and the energy needs to be dynamically compensated through correction terms. The power correction formula for a single partition is: , where: k is the power correction factor, h i For the i zonal silt thickness; t i For the i Partitioned silt shear strength. k Negatively correlated with the organic matter content of silt, i.e. , k 0 =0.1, l =0.05 kg / kJ. As verified in Example 3, when the organic matter content of sludge is greater than 30%, the correction coefficient k Take 0.25-0.3, because organic matter has high microwave absorption efficiency, it is necessary to reduce the power increment to avoid local overheating; when the content is ≤30%, k Take 0.1-0.2. At this time, inorganic matter is the main substance, and the power needs to be increased to destroy the mineral crystal structure.

[0078] Considering the area ratio, which reflects the energy contribution ratio of the partition in the entire sedimentation tank, the single partition correction amount is obtained after weighting: , summing over all partitions to obtain the power correction term: , it can be seen that the power correction term is determined by the product of thickness, shear strength and area ratio, such as the partition 3 ΔP The largest, energy needs to be allocated first; soft areas such as partitions 4 and 5 ΔP The dynamic power is automatically attenuated to avoid excess energy. Therefore, dynamic power adjustment of "more energy in hard areas and less energy in soft areas" is achieved through multi-parameter weighting, which meets the actual needs of sludge breaking.

[0079] From this we can see that the power dynamic adjustment model: .

[0080] Based on the spatial distribution characteristics of silt shear strength, the motion trajectory is dynamically correlated with the velocity and shear strength. Figure 9As shown, the transverse velocity is only related to the difference between the maximum shear strength and the average value of the partitions. v x =0.818m / min, the lateral speed of the hard and soft areas is consistent to ensure global coverage uniformity; the longitudinal speed varies with the partition t i The speed decreases and increases, that is, zone 1: 0.327m / min → zone 5: 0.464m / min, and the action time of the hard zone is extended by more than 50%; therefore, through the dual-axis control of "lateral uniform coverage + longitudinal hardness response", the problem of "insufficient action of the hard zone and excessive treatment of the soft zone" in the fixed speed mode is further solved.

[0081] This indicates that microwave dynamic adjustment can improve hard zone removal efficiency by 15% to 25%, while reducing tank wear depth by 62.5%. This also demonstrates that microwave dynamic adjustment can improve dredging efficiency, reduce energy consumption, lower maintenance costs, ensure long-term stable operation of the sedimentation tank, and optimize the overall dredging process. By precisely controlling microwave radiation time and power, effective silt removal is achieved in each zone, avoiding energy waste and improving overall dredging effectiveness.

[0082] The above shows and describes the main features and advantages of the present invention. It is obvious to those skilled in the art that the specific implementation of the present invention is not limited to the details of the above exemplary embodiments. In addition, without departing from the spirit or essential characteristics of the present invention, the creative ideas and design concepts of the present invention can be implemented in other specific forms, which should be equivalent to the scope of protection disclosed in the technical solution of the present invention. Therefore, from all points of view, the embodiments should be regarded as exemplary and non-restrictive. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, all changes that fall within the meaning and scope of the equivalent elements of the claims are intended to be included in the present invention.

[0083] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A method for desilting sedimentation tanks for treating domestic sewage and coal washing plant sewage, characterized in that: The following steps are involved: Step 1: Conduct an on-site survey of the sedimentation tank, collect design information and real-time sewage level data, obtain silt thickness and distribution area data, calculate sewage treatment capacity and silt removal volume, and formulate a dredging plan; Step 2: Build an enclosed work shed and equip it with ventilation and air purification equipment to create a closed working environment. Simultaneously, install a gantry and work platform that can move horizontally and vertically in the enclosed work shed. Install microwave radiation equipment, stirring equipment, cleaning equipment, and spraying equipment on the work platform according to the needs of the dredging operation to facilitate multi-angle and all-round dredging operations. Step 3: Add composite flocculant to the sedimentation tank according to the sewage treatment volume, start the stirring equipment to stir, and make the sludge flocculate and settle; Step 4: Use the drainage pump to drain the upper layer of clear water in the sedimentation tank to the nearby sewage collection tank, and then start the mud pump to pump the lower layer of flocculent matter out of the sedimentation tank until the hardened sludge surface is exposed; Step 5: Use a microwave radiation device to pre-treat the surface of the hardened sludge to induce a network of thermal stress cracks in the hardened layer, and then use a cleaning device to flush it to form a flowing sludge; Step 6: Use a mud pump to pump the mud out of the sedimentation tank. The flocculants and sludge are then dehydrated by gravity concentration, belt filter press, and plate and frame filter press to form a mud cake. Step 7: After the sludge is cleaned, use the cleaning equipment to clean the wall and bottom of the sedimentation tank to remove the residual dirt, continue to start the mud pump to pump the mud produced by cleaning to the mud tank truck again, then spray the biological conditioner to enzymatically hydrolyze the residual organic matter, use the cleaning equipment again to clean the sedimentation tank for the second time, and use the mud pump to pump the mud produced by the second cleaning to the mud tank truck to ensure that the environment in the sedimentation tank is completely purified; Step 8: Check the sedimentation tank wall and bottom for damage. If so, repair them. Otherwise, proceed directly to step 9. Step 9: Spray nano-ceramic anti-corrosion coating on the inner wall of the sedimentation tank for anti-corrosion treatment; Step 10: After the project is accepted, dismantle the enclosed work shed and supporting equipment, clean up the site, restore it to its original state, and put it into use.

2. The sedimentation tank desilting construction method for treating domestic sewage and coal washing plant wastewater according to claim 1, characterized in that: In step 1, the silt thickness and distribution area data are obtained by the following method: Step 1.1: Use a multi-beam sonar detector to scan the bottom of the sedimentation tank, and simultaneously use a laser turbidity meter or fluorescence sensor to obtain the physical and chemical characteristics of the sludge surface; Step 1.2: Use geographic information system software to fuse sonar echo data and texture features to generate a three-dimensional silt thickness model and mark the silt distribution area; Step 1.3: For areas with abnormal sonar data, collect silt column samples using a gravity sampler, test the moisture content, particle size distribution, and shear strength, and revise the data model.

3. The sedimentation tank desilting construction method for treating domestic sewage and coal washing plant wastewater according to claim 2, characterized in that: In step 1, the sludge removal amount is calculated as follows: ， Where, ρ is the silt density, and the value range of domestic sewage silt is 1.05-1.3t / m 3 The value range of coal washing plant sewage sludge is 1.2-1.5t / m 3 ; w is the moisture content of sludge, which is tested by drying method and the value range is 60%-90%; ε is the loss rate during sludge removal; V s The actual volume of sludge removed; The calculation formula for sewage treatment capacity is as follows: ; in, A is the bottom area of the sedimentation tank, H 0 is the sewage level before desilting; H 1 is the water level after pumping; The actual sludge removal volume is calculated by the following formula: , Where, A i For sedimentation tank i The area of the desilting zone, h i No. i Average silt thickness in each zone, n is the total number of dredging zones.

4. The sedimentation tank desilting construction method for treating domestic sewage and coal washing plant wastewater according to claim 3, characterized in that: In step 3, the composite flocculant is added through a metering pump, and after the addition, a submersible mixer is started to fully mix the flocculant and the sewage to form stable flocs.

5. The sedimentation tank desilting construction method for treating domestic sewage and coal washing plant wastewater according to claim 2, characterized in that: In step 5, the microwave radiation device uses a microwave generator to dynamically adjust the radiation power and movement trajectory according to the real-time acquired silt thickness data, so that the microwaves evenly cover the surface of the hardened silt.

6. The sedimentation tank desilting construction method for treating domestic sewage and coal washing plant wastewater according to claim 5, characterized in that: The radiation power of the microwave radiation device is dynamically adjusted by: Microwave generator output power , Where: P 0 It is the basic power, ranging from 50-100kW, determined by the sedimentation tank design parameters; k is the power correction coefficient, with a value of 0.1-0.3, which mainly reflects the energy compensation efficiency of the microwave generator for silts of different hardness and is negatively correlated with the organic matter content of the silt; h i For the i zonal silt thickness; τ i For the i Zonal silt shear strength; A i / A For the i The proportion of the partition area reflects the weight of the power demand of different hardness areas; The movement trajectory of the microwave radiation device is dynamically adjusted by: Lateral movement speed , Where: υ x is the lateral moving speed, the design value range is 0.5-2m / min; υ 0 The horizontal reference speed is 1m / min by default; max( τ i ) is the maximum shear strength of the partition; τ avg is the average shear strength of the desilting area; when the difference in silt hardness is greater, the lateral movement speed is slower, which can ensure the uniformity of microwave coverage in areas with different hardness; Vertical movement speed , Where: υ y is the longitudinal moving speed, the design value range is 0.2-1.0m / min; It is the longitudinal reference speed, the default value is 0.6m / min; When the partition silt shear strength τ i The higher it is, the slower the longitudinal movement speed is, and it is necessary to increase the microwave action time on the hardened sludge; when τ i> 2 τ avg When the gantry's supporting controller is pressed υ y =0.4 implement.

7. The sedimentation tank desilting construction method for treating domestic sewage and coal washing plant sewage according to claim 2, characterized in that: In step 6, the inlet side of the mud pump pipe is connected to the metal hose through a three-way joint and communicated with the air outlet of the hollow fiber membrane aeration device, and micro-nano bubbles are injected and mixed with the mud by the spiral blades of the mud pump to form a vortex state of the mud to reduce the transportation resistance.

8. The sedimentation tank desilting construction method for treating domestic sewage and coal washing plant sewage according to claim 7, characterized in that: In step 6, a bio-enzyme compound conditioner is added through a metering pump before feeding the belt filter press. The bio-enzyme compound conditioner and micro-nano bubbles synergistically decompose organic matter in the sludge, thereby improving the sludge dewatering efficiency.

9. The sedimentation tank desilting construction method for treating domestic sewage and coal washing plant wastewater according to claim 1, characterized in that: In step 7, the biological conditioner is evenly sprayed onto the surface of the sedimentation tank using a spraying device to ensure comprehensive coverage and promote uniform degradation of sludge.

10. The sedimentation tank desilting construction method for treating domestic sewage and coal washing plant wastewater according to claim 1, characterized in that: In step 8, the nano-ceramic anti-corrosion coating is evenly sprayed onto the inner wall of the sedimentation tank using a spraying device to enhance the corrosion resistance of the tank body and extend its service life.

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