A stacked high-pressure control method for sludge dewatering

Abstract

This invention relates to the field of wastewater treatment technology, specifically disclosing a layered high-pressure control method for sludge dewatering, comprising the following steps: sludge pretreatment: Domestic sludge is transported to a conditioning reactor, a cationic desiccant is added, and the mixture is stirred; a lignocellulose-based conditioning agent and a chitosan derivative are added, and the mixture is stirred; layering and spreading: sludge is evenly spread between two layers of filter cloth to form a sludge layer; multiple spreading units are horizontally stacked in an adjustable filter press basket, with drainage channels formed by two layers of filter cloth between adjacent sludge layers; multi-stage pressing: pressure is applied using a vertical double-piston pressing mechanism; pressure transmission adopts a gradient pressurization mode; drainage control: the thickness change of each sludge layer is monitored in real time using an ultrasonic thickness measuring device, and pressure parameters are dynamically adjusted according to the thickness change; filter water is discharged laterally through the drainage channels formed by the multi-layered filter cloth and introduced into a water treatment unit via a collection system. This invention can efficiently dewater various types of sludge and is environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a stacked high-pressure control method for sludge dewatering. Background Technology

[0002] With the acceleration of urbanization, the amount of domestic sewage sludge generated by wastewater treatment plants has increased dramatically. Its high water content leads to significant treatment challenges, high transportation costs, and substantial environmental risks. Current mainstream dewatering technologies include belt filter presses, centrifugal dewatering, and plate and frame filter presses. While these technologies can achieve some degree of volume reduction, they generally suffer from problems such as high water content in the dewatered sludge (typically >80%), high energy consumption, and high operating costs. In particular, for domestic sewage sludge with a stable colloidal structure, traditional mechanical dewatering methods struggle to disrupt the bound water state, limiting dewatering efficiency.

[0003] In existing technologies, sludge conditioning often employs organic flocculants such as polyacrylamide or inorganic modifiers such as lime, which not only require large dosages (typically >5%) but also easily cause secondary pollution and sludge volume expansion. Regarding equipment, traditional filter presses generally suffer from low automation, rudimentary process parameter control, and high energy and water consumption, making it difficult to meet the dual requirements of modern wastewater treatment plants for energy conservation, consumption reduction, and resource recovery. Therefore, developing a new sludge treatment process that achieves deep dewatering, low system energy consumption, and high resource recovery is of great significance. Summary of the Invention

[0004] To address the problems existing in the prior art, the present invention provides a stacked high-pressure control method for sludge dewatering.

[0005] The technical solution adopted in this invention is:

[0006] A multi-stage high-pressure control method for sludge dewatering includes the following steps:

[0007] Sludge pretreatment: Domestic sewage sludge with a moisture content of 90% to 99% is transported to a conditioning reactor. First, a cationic desiccant of 0.5‰ to 2‰ of the wet sludge mass is added, and the mixture is stirred at 200 to 400 r / min for 5 to 15 minutes. Then, a lignocellulose-based conditioning agent of 1‰ to 3‰ of the wet sludge mass and a chitosan derivative of 0.5‰ to 1.5‰ are added, and the mixture is stirred at 35 to 45°C for 10 to 20 minutes.

[0008] Layered sludge: The conditioned sludge is evenly spread between two layers of filter cloth through a quantitative feeding device to form a sludge layer with a thickness of 8-18mm. The effective filtration area of ​​a single sludge layer unit is controlled at 2-5m². Multiple sludge layers are horizontally stacked in an adjustable filter press basket, with a stacking number of 10-30 layers. A drainage channel composed of two layers of filter cloth is formed between adjacent sludge layers.

[0009] Multi-stage pressing: A vertical double-piston pressing mechanism is adopted. The upper piston applies an initial pressure of 50-200T and holds the pressure for 3-8 minutes. Then, the lower piston applies a secondary pressure of 100-400T and holds the pressure for 5-15 minutes. The pressure transmission adopts a gradient pressurization mode, and the pressure rise rate is controlled at 10-30T / min.

[0010] Drainage control: During the pressing process, the thickness change of each layer of sludge is monitored in real time by an ultrasonic thickness measuring device set on the side of the basket, and the pressure parameters are dynamically adjusted according to the thickness change; the filter water is discharged laterally through the drainage channel formed by multiple layers of filter cloth and introduced into the water treatment unit through the collection system.

[0011] Preferably, the conditioning reactor in the sludge pretreatment is equipped with an automatic pH adjustment system to control the pH value of the sludge within the range of 6.5 to 7.5, and is also equipped with an online viscosity monitoring device to ensure that the viscosity of the sludge after conditioning is 500 to 1500 mPa·s.

[0012] Preferably, the wood fiber conditioning agent used in the sludge pretreatment is a refined product of bagasse papermaking waste, with a fiber length controlled at 0.2-1.2 mm and an aspect ratio ≥20:1, and is pretreated with 2%-5% sodium hydroxide solution.

[0013] Preferably, the filter cloth in the layered mulch has a three-layer composite structure, including a polyester spunbond nonwoven fabric in contact with the sludge layer, an ultra-high molecular weight polyethylene woven mesh in the middle layer, and a polypropylene monofilament filter cloth in the outer layer.

[0014] Preferably, the adjustable filter press basket in the layered material laying adopts a modular design, and the height of the side plate can be steplessly adjusted within the range of 100-300mm by a hydraulic adjustment device to adapt to the needs of different layering quantities.

[0015] Preferably, in multi-stage pressing, the dual-piston pressing mechanism adopts a hydraulic servo control system with a pressure control accuracy of ±0.5T, and the upper and lower pistons can be independently programmed to control the pressure curve.

[0016] Preferably, in drainage control, the ultrasonic thickness measuring device adopts a multi-probe array arrangement, with 3 to 5 thickness measuring points set for each filter press unit, and the measurement accuracy reaches ±0.1mm.

[0017] Preferably, the process also includes unloading and filter cloth regeneration: after pressing, the dewatered sludge cake is separated, and the filter cloth is recycled after being rinsed with high-pressure water and ultrasonically cleaned.

[0018] Preferably, the process also includes post-treatment of the sludge cake: the dewatered sludge cake is crushed to a particle size of 2-5 mm, 5%-10% of biomass additives are added, and the cake is dried at a low temperature of 50-65°C to produce an organic fertilizer product.

[0019] The beneficial effects of this invention are:

[0020] 1. A systematic upgrade of the sludge dewatering process has been achieved. In the pretreatment stage, a combination of composite conditioning agents is used. First, a cationic breaker is used to break down the colloidal structure, and then the synergistic effect of lignocellulose and chitosan derivatives improves the sludge floc structure, thereby improving the subsequent dewatering efficiency. The heating control system maintains the optimal reaction temperature of 35-45℃, which enhances the activity of the treatment agent and shortens the reaction time. In the layering stage, the thickness and number of layers are precisely controlled to increase the filtration area per unit volume of sludge. In the multi-stage pressing stage, a dual-piston gradient pressurization mode is adopted. The combination of initial compaction by the upper piston and deep pressing by the lower piston avoids damage to the filter cloth caused by sudden pressure increases and ensures efficient water removal and improved pressure utilization. In the drainage control stage, an ultrasonic real-time monitoring system is introduced, which can dynamically adjust the pressure parameters according to the compression state of each layer of sludge to ensure dewatering uniformity and reduce moisture content deviation.

[0021] 2. By controlling the sludge pH value within the optimal range of 6.5 to 7.5, the activity of the cationic decolloid is ensured while avoiding the impact of extreme pH values ​​on subsequent treatment equipment, thus improving the stability of the conditioning effect. Online viscosity monitoring enables quantitative control of the conditioning degree. When the viscosity exceeds the set range, the stirring intensity and the dosage of the treatment agent are automatically adjusted to avoid over-conditioning or under-conditioning. This achieves standardization and automation of the pretreatment process, improving the consistency of sludge treatment quality.

[0022] 3. By using refined products from bagasse papermaking waste as a wood fiber conditioning agent, the dual benefits of waste resource utilization and sludge conditioning are achieved. In terms of physical modification, controlling the fiber length to 0.2–1.2 mm and the aspect ratio to ≥20:1 allows the fibers to form a three-dimensional network structure in the sludge, effectively improving the pore structure and permeability of the sludge and reducing filter cake resistance. In terms of chemical treatment, pretreatment with 2%–5% sodium hydroxide solution removes hydrophobic substances from the fiber surface and increases the number of hydrophilic groups such as hydroxyl groups, thereby improving the binding ability of the fibers to sludge particles. The use of this conditioning agent reduces the capillary water absorption time of the sludge, increases the dewatering rate, and avoids the secondary pollution problems caused by traditional chemical conditioning agents, thus reducing treatment costs.

[0023] 4. The three-layer composite filter cloth structure achieves an optimal balance between filtration accuracy, drainage efficiency, and mechanical strength. The contact layer uses polyester spunbond nonwoven fabric, whose microporous structure effectively traps fine sludge particles while providing appropriate surface roughness for easy sludge cake removal and improved unloading integrity. The middle layer, made of ultra-high molecular weight polyethylene woven mesh, forms a stable drainage channel network. Its unique weaving structure increases the lateral drainage speed and pressure resistance. The outer layer, made of polypropylene monofilament filter cloth, provides good mechanical strength and wear resistance, high tensile strength, and extended service life. The synergistic effect of the three layers reduces overall filtration resistance and increases drainage throughput.

[0024] 5. The modular design of the adjustable filter press basket achieves high flexibility and adaptability of the equipment. The hydraulic adjustment device allows the side plate height to be steplessly adjusted within the range of 100-300mm, and the number of layers can be quickly adjusted according to the processing volume and sludge characteristics, improving equipment utilization. The modular design allows the basket to adapt to different scales of processing needs: small treatment stations can use fewer layers to achieve energy-saving operation; large treatment centers can use the maximum number of layers to achieve large-scale processing. This design allows a single unit to process various types of sludge with different moisture contents, expanding its applicability.

[0025] 6. The introduction of the hydraulic servo control system enables precision and intelligence in the pressing process, with pressure control accuracy reaching ±0.5T. This ensures the stability and repeatability of pressure application, avoiding filter cloth damage and uneven dewatering caused by pressure fluctuations. The independent programming control function allows the upper and lower pistons to execute different pressure curves: the upper piston can adopt a stepped pressurization mode to effectively discharge free water; the lower piston adopts a linear pressurization mode to deeply remove bound water. This staged control strategy improves the dewatering efficiency per unit energy consumption while avoiding the "compaction phenomenon" of sludge and maintaining good permeability. The system has a fast response speed and can adapt to changes in sludge characteristics in real time, ensuring that the dewatering process is always in an optimal state.

[0026] 7. The application of a multi-probe ultrasonic thickness measurement system enables real-time monitoring and precise control of the dewatering process; the measurement accuracy reaches ±0.1mm, accurately reflecting the compression state and dewatering progress of each layer of sludge, providing reliable data support for pressure regulation; the multi-probe array arrangement ensures comprehensive monitoring, enabling the detection of localized uneven dewatering and timely adjustment of pressure distribution; real-time feedback control allows the system to dynamically adjust pressure parameters according to thickness changes: when a layer is detected to be dewatering too quickly, the pressure in that area is automatically reduced; when dewatering is detected to be lagging, the pressure is appropriately increased; this adaptive control improves dewatering uniformity, avoids over- or under-pressing, and significantly improves product quality stability.

[0027] 8. The unloading and regeneration process uses a combination of high-pressure water rinsing and ultrasonic cleaning to improve the regeneration efficiency of the filter cloth and extend its service life.

[0028] 9. The addition of sludge cake in the resource utilization stage forms a complete closed loop from treatment to utilization; crushing the sludge cake to a particle size of 2-5mm gives it a suitable specific surface area, which is beneficial for subsequent uniform mixing and maintains good air permeability; the addition of biomass additives effectively adjusts the carbon-nitrogen ratio, improves the fermentation conditions in the composting process, and increases porosity, thereby improving aerobic fermentation efficiency; low-temperature drying kills pathogens while preserving the activity of organic matter, avoiding nutrient loss caused by high-temperature treatment; the final organic fertilizer product has an extended fertilizer effect duration, realizing the value-added utilization of sludge. Attached Figure Description

[0029] Figure 1 This is a flowchart of the control method in an embodiment of the invention. Detailed Implementation

[0030] The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0031] Example 1

[0032] A stacked high-pressure control method for sludge dewatering, such as Figure 1 As shown, it includes the following steps:

[0033] Sludge pretreatment: Domestic sewage sludge with a moisture content of 90% is transported to a conditioning reactor. The conditioning reactor is equipped with an automatic pH adjustment system to control the pH value of the sludge within the range of 6.5, and is also equipped with an online viscosity monitoring device to ensure that the viscosity of the sludge after conditioning is 500 mPa·s. First, 0.5‰ of the wet sludge mass of cationic breaker is added and stirred at 200 r / min for 5 minutes. Then, 1‰ of the wet sludge mass of wood fiber-based conditioner and 0.5‰ of chitosan derivative are added and stirred for another 10 minutes at 35℃. The wood fiber-based conditioner is a refined product of bagasse papermaking waste, with a fiber length controlled at 0.2 mm, an aspect ratio ≥20:1, and pretreated with 2% sodium hydroxide solution.

[0034] Layered sludge preparation: The conditioned sludge is evenly laid between two layers of filter cloth using a quantitative feeding device to form a sludge layer with a thickness of 8mm, which is a single sludge preparation unit. The filter cloth has a three-layer composite structure, including a polyester spunbond nonwoven fabric with a unit area mass of 80g / m² in contact with the sludge layer, an ultra-high molecular weight polyethylene woven mesh with a warp and weft density of 20 threads / cm in the middle layer, and a polypropylene monofilament filter cloth with a filament diameter of 0.1mm in the outer layer. The effective filtration area of ​​a single sludge preparation unit is controlled at 2m². Multiple sludge preparation units are horizontally stacked in an adjustable filter press basket, with a stacking quantity of 10 layers. A drainage channel consisting of two layers of filter cloth is formed between adjacent sludge layers. The adjustable filter press basket adopts a modular design, and the height of the side plate can be steplessly adjusted within a range of 100mm via a hydraulic adjustment device to adapt to different stacking quantities.

[0035] Multi-stage pressing: A vertical double-piston pressing mechanism is adopted. The upper piston applies an initial pressure of 50T and holds the pressure for 3 minutes. Then, the lower piston applies a secondary pressure of 100T and holds the pressure for 5 minutes. The pressure transmission adopts a gradient pressurization mode, and the pressure rise rate is controlled at 10T / min. In multi-stage pressing, the double-piston pressing mechanism adopts a hydraulic servo control system with a pressure control accuracy of ±0.5T. The pressure curves of the upper and lower pistons can be independently programmed and controlled.

[0036] Drainage control: During the pressing process, the thickness change of each layer of sludge is monitored in real time by an ultrasonic thickness measuring device set on the side of the basket. The pressure parameters are dynamically adjusted according to the thickness change. The ultrasonic thickness measuring device adopts a multi-probe array arrangement, with 3 thickness measuring points set for each filter pressing unit, and the measurement accuracy reaches ±0.1mm. The filter water is discharged laterally through the drainage channel formed by multiple layers of filter cloth and introduced into the water treatment unit through the collection system.

[0037] Unloading and filter cloth regeneration: After pressing, the dewatered sludge cake is separated, and the filter cloth is recycled after being washed with 0.8MPa high-pressure water and cleaned with 28kHz ultrasonic waves.

[0038] Subsequent processing of sludge cake: The dehydrated sludge cake is crushed to a particle size of 2mm, 5% of biomass additives (wood chips, straw powder, etc.) are added, and then dried at a low temperature of 50℃ to produce organic fertilizer products.

[0039] Example 2

[0040] A stacked high-pressure control method for sludge dewatering, such as Figure 1 As shown, it includes the following steps:

[0041] Sludge pretreatment: Domestic sewage sludge with a moisture content of 95% is transported to a conditioning reactor. The conditioning reactor is equipped with an automatic pH adjustment system to control the pH value of the sludge within the range of 7, and is also equipped with an online viscosity monitoring device to ensure that the viscosity of the sludge after conditioning is 1000 mPa·s. First, a cationic breaker with a mass of 1‰ of the wet sludge is added and stirred at 300 r / min for 10 minutes. Then, a wood fiber-based conditioner with a mass of 2‰ of the wet sludge and a chitosan derivative with a mass of 1‰ are added and stirred for another 15 minutes at 40℃. The wood fiber-based conditioner is a refined product of bagasse papermaking waste, with a fiber length controlled at 0.8 mm and an aspect ratio ≥20:1, and has been pretreated with a 3.5% sodium hydroxide solution.

[0042] Layered sludge preparation: The conditioned sludge is evenly laid between two layers of filter cloth using a quantitative feeding device to form a sludge layer with a thickness of 13mm, which is a single sludge preparation unit. The filter cloth has a three-layer composite structure, including a polyester spunbond nonwoven fabric with a unit area mass of 100g / m² in contact with the sludge layer, an ultra-high molecular weight polyethylene woven mesh with a warp and weft density of 25 threads / cm in the middle layer, and a polypropylene monofilament filter cloth with a filament diameter of 0.2mm on the outer layer. The effective filtration area of ​​a single sludge preparation unit is controlled at 3.5m². Multiple sludge preparation units are horizontally stacked in an adjustable filter press basket, with a stacking quantity of 20 layers. A drainage channel consisting of two layers of filter cloth is formed between adjacent sludge layers. The adjustable filter press basket adopts a modular design, and the height of the side plate can be steplessly adjusted within a range of 200mm via a hydraulic adjustment device to adapt to different stacking quantities.

[0043] Multi-stage pressing: A vertical double-piston pressing mechanism is adopted. The upper piston applies an initial pressure of 125T and holds the pressure for 6 minutes. Then, the lower piston applies a secondary pressure of 250T and holds the pressure for 10 minutes. The pressure transmission adopts a gradient pressurization mode, and the pressure rise rate is controlled at 20T / min. In multi-stage pressing, the double-piston pressing mechanism adopts a hydraulic servo control system with a pressure control accuracy of ±0.5T. Moreover, the pressure curves of the upper and lower pistons can be independently programmed and controlled.

[0044] Drainage control: During the pressing process, the thickness change of each layer of sludge is monitored in real time by an ultrasonic thickness measuring device set on the side of the frame basket. The pressure parameters are dynamically adjusted according to the thickness change. The ultrasonic thickness measuring device adopts a multi-probe array arrangement, with 4 thickness measuring points set for each filter pressing unit, and the measurement accuracy reaches ±0.1mm. The filter water is discharged laterally through the drainage channel formed by multiple layers of filter cloth and introduced into the water treatment unit through the collection system.

[0045] Unloading and filter cloth regeneration: After pressing, the dewatered sludge cake is separated, and the filter cloth is recycled after being washed with 1MPa high-pressure water and cleaned with 34kHz ultrasonic waves.

[0046] Subsequent processing of sludge cake: The dehydrated sludge cake is crushed to a particle size of 3.5mm, 7.5% biomass additives (wood chips, straw powder, etc.) are added, and then dried at a low temperature of 60℃ to produce organic fertilizer products.

[0047] Example 3

[0048] A stacked high-pressure control method for sludge dewatering, such as Figure 1 As shown, it includes the following steps:

[0049] Sludge pretreatment: Domestic sewage sludge with a moisture content of 99% is transported to a conditioning reactor. The conditioning reactor is equipped with an automatic pH adjustment system to control the pH value of the sludge within the range of 7.5, and is also equipped with an online viscosity monitoring device to ensure that the viscosity of the sludge after conditioning is 1500 mPa·s. First, 2‰ of the wet sludge mass of cationic breaker is added and stirred at 400 r / min for 15 minutes. Then, 3‰ of the wet sludge mass of wood fiber-based conditioner and 1.5‰ of chitosan derivative are added and stirred at 45℃ for 20 minutes. The wood fiber-based conditioner is a refined product of bagasse papermaking waste, with a fiber length controlled at 1.2 mm, an aspect ratio ≥20:1, and pretreated with 5% sodium hydroxide solution.

[0050] Layered sludge preparation: The conditioned sludge is evenly laid between two layers of filter cloth using a quantitative feeding device to form a sludge layer with a thickness of 18mm, which is a single sludge preparation unit. The filter cloth has a three-layer composite structure, including a polyester spunbond nonwoven fabric with a unit area mass of 120g / m² in contact with the sludge layer, an ultra-high molecular weight polyethylene woven mesh with a warp and weft density of 25 threads / cm in the middle layer, and a polypropylene monofilament filter cloth with a filament diameter of 0.3mm in the outer layer. The effective filtration area of ​​a single sludge preparation unit is controlled at 5m². Multiple sludge preparation units are horizontally stacked in an adjustable filter press basket, with a stacking quantity of 30 layers. A drainage channel consisting of two layers of filter cloth is formed between adjacent sludge layers. The adjustable filter press basket adopts a modular design, and the height of the side plate can be steplessly adjusted within a range of 300mm via a hydraulic adjustment device to adapt to different stacking quantities.

[0051] Multi-stage pressing: A vertical double-piston pressing mechanism is adopted. The upper piston applies an initial pressure of 200T and holds the pressure for 8 minutes. Then, the lower piston applies a secondary pressure of 400T and holds the pressure for 15 minutes. The pressure transmission adopts a gradient pressurization mode, and the pressure rise rate is controlled at 30T / min. In multi-stage pressing, the double-piston pressing mechanism adopts a hydraulic servo control system with a pressure control accuracy of ±0.5T. Moreover, the pressure curves of the upper and lower pistons can be independently programmed and controlled.

[0052] Drainage control: During the pressing process, the thickness change of each layer of sludge is monitored in real time by an ultrasonic thickness measuring device set on the side of the basket. The pressure parameters are dynamically adjusted according to the thickness change. The ultrasonic thickness measuring device adopts a multi-probe array arrangement, with 5 thickness measuring points set for each filter pressing unit, and the measurement accuracy reaches ±0.1mm. The filter water is discharged laterally through the drainage channel formed by multiple layers of filter cloth and introduced into the water treatment unit through the collection system.

[0053] Unloading and filter cloth regeneration: After pressing, the dewatered sludge cake is separated, and the filter cloth is washed with 1.2MPa high-pressure water and cleaned with 40kHz ultrasonic cleaner before being recycled;

[0054] Subsequent processing of sludge cake: The dehydrated sludge cake is crushed to a particle size of 5mm, 10% of biomass additives (wood chips, straw powder, etc.) are added, and then dried at a low temperature of 65℃ to produce organic fertilizer products.

[0055] Experimental Example 1

[0056] The method described in Example 1 was used to treat concentrated sludge (90% moisture content) from a municipal wastewater treatment plant. First, 0.5‰ C8H was added to the conditioning reactor. 16 N·Cl cationic breaker was added, followed by stirring for 10 minutes. Then, 1‰ of a lignocellulose conditioner and 0.5‰ of a chitosan derivative were added, and stirring continued at 35°C for another 10 minutes. The conditioned sludge was then evenly spread between specially designed filter cloths (8mm thick per layer) using a high-pressure spraying method, with a total of 10 units stacked. A double-piston pressing process was used (upper piston 50T pressure for 3 minutes, lower piston 100T pressure for 10 minutes), ultimately yielding a sludge cake with a moisture content of 43%. The treated water COD was ≤100mg / L, meeting the discharge standards.

[0057] Experimental Example 2

[0058] The method described in Example 2 was used to treat food processing sludge with high organic matter content (moisture content 95%, COD > 5000 mg / L). The treatment agent ratio was adjusted to 1‰ C8H 16 The mixture consists of N·Cl cationic degreasing agent, 2‰ lignocellulose, and 1‰ chitosan / chitosan derivative, with an added pH adjustment unit to control the pH at 7.0. A 20-layer stacked structure is used, with dual piston pressure adjustments: 125T for 6 minutes + 250T for 10 minutes. The final sludge cake has a moisture content of 41% and an organic matter retention rate >85%, making it suitable for organic fertilizer production.

[0059] Experimental Example 3

[0060] The method described in Example 3 was used to treat highly viscous industrial sludge with a viscosity of 2000 mPa·s, with the addition of a pretreatment step: first, 1‰ hydrogen peroxide was added for oxidation, followed by 2‰ C8H2O. 16N·Cl cationic degumming agent + 3‰ lignocellulose + 1.5‰ chitosan and chitosan derivatives. A high layer count (30 layers) and a high pressure rise rate (30T / min) were employed. Ultimately, this ensured effective dehydration (45% moisture content) while avoiding filter cloth clogging.

[0061] In summary, the present invention has the following significant advantages:

[0062] 1. Excellent dehydration performance

[0063] Through the synergistic effect of a composite conditioner system and multi-layer pressing technology, the moisture content of various types of sludge was successfully reduced to below 45% (Experimental Example 1: 43%, Experimental Example 2: 41%, Experimental Example 3: 45%), improving dewatering efficiency compared to traditional methods. In particular, it maintains stable dewatering effects for special sludge with high organic matter content and high viscosity, solving the problem of inconsistent performance when treating special sludge using existing technologies.

[0064] 2. Wide adaptability

[0065] Examples demonstrate that the present invention can effectively treat different types of sludge, including municipal sewage sludge (Example 1), food processing organic sludge (Example 2), and high-viscosity industrial sludge (Example 3). By adjusting the treatment agent ratio, the number of layers, and the pressure parameters, the system can adapt to various sludge characteristics, expanding its applicability and overcoming the limitations of traditional equipment on sludge types.

[0066] 3. Significant energy-saving benefits

[0067] By employing dual-piston gradient pressurization and intelligent control technology, unit energy consumption is reduced. When treating high-concentration sludge, energy consumption is lower than that of traditional methods. At the same time, through the filter cloth regeneration system and water recovery and reuse, economic benefits are achieved by reducing operating costs.

[0068] 4. High degree of resource utilization

[0069] The dewatered sludge cake retained more than 85% of its organic matter (Experimental Example 2), and could be directly used for organic fertilizer production, realizing the transformation from waste treatment to resource conversion. The clean water recovery rate was more than 80%, and the COD of the treated water was ≤100mg / L, fully meeting the discharge standards and forming a complete resource recycling system.

[0070] 5. High level of intelligent operation

[0071] Through centralized PLC control and real-time monitoring of multiple parameters, the entire process is automated. The system can automatically optimize operating parameters based on sludge characteristics, reducing the number of operators, lowering maintenance costs, and achieving intelligent upgrading of the wastewater treatment plant.

[0072] 6. Environmentally friendly processes

[0073] The use of a non-toxic and harmless treatment agent system avoids the secondary pollution problems caused by metal salts and PAM in traditional methods. The entire process is odorless, with low noise pollution, truly achieving clean production and significantly improving environmental compatibility.

[0074] The embodiments described above are merely illustrative of specific implementations of the present invention, and while the descriptions are detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention.

Claims

1. A stacked high-pressure control method for sludge dewatering, characterized in that, Includes the following steps: Sludge pretreatment: Domestic sewage sludge with a moisture content of 90% to 99% is transported to a conditioning reactor. First, a cationic desiccant of 0.5‰ to 2‰ of the wet sludge mass is added, and the mixture is stirred at 200 to 400 r / min for 5 to 15 minutes. Then, a lignocellulose-based conditioning agent of 1‰ to 3‰ of the wet sludge mass and a chitosan derivative of 0.5‰ to 1.5‰ are added, and the mixture is stirred at 35 to 45°C for 10 to 20 minutes. Layered sludge preparation: The conditioned sludge is evenly spread between two layers of filter cloth through a quantitative feeding device to form a sludge layer with a thickness of 8-18mm, which is a single sludge preparation unit. The effective filtration area of ​​a single sludge preparation unit is controlled at 2-5m². Multiple sludge preparation units are horizontally stacked in an adjustable filter press basket, with a stacking number of 10-30 layers. A drainage channel composed of two layers of filter cloth is formed between adjacent sludge layers. Multi-stage pressing: A vertical double-piston pressing mechanism is adopted. The upper piston applies an initial pressure of 50-200T and holds the pressure for 3-8 minutes. Then, the lower piston applies a secondary pressure of 100-400T and holds the pressure for 5-15 minutes. The pressure transmission adopts a gradient pressurization mode, and the pressure rise rate is controlled at 10-30T / min. Drainage control: During the pressing process, the thickness change of each layer of sludge is monitored in real time by an ultrasonic thickness measuring device set on the side of the basket, and the pressure parameters are dynamically adjusted according to the thickness change; the filter water is discharged laterally through the drainage channel formed by multiple layers of filter cloth and introduced into the water treatment unit through the collection system.

2. The stacked high-pressure control method for sludge dewatering according to claim 1, characterized in that, The sludge pretreatment conditioning reactor is equipped with an automatic pH adjustment system to control the pH value of the sludge within the range of 6.5 to 7.5, and is also equipped with an online viscosity monitoring device to ensure that the viscosity of the sludge after conditioning is 500 to 1500 mPa·s.

3. The stacked high-pressure control method for sludge dewatering according to claim 2, characterized in that, In the sludge pretreatment, the wood fiber base conditioner is a refined product of bagasse papermaking waste. Its fiber length is controlled at 0.2-1.2 mm, the aspect ratio is ≥20:1, and it has been pretreated with 2%-5% sodium hydroxide solution.

4. The stacked high-pressure control method for sludge dewatering according to claim 3, characterized in that, In the layered material, the filter cloth has a three-layer composite structure, including a polyester spunbond nonwoven fabric in contact with the sludge layer, an ultra-high molecular weight polyethylene woven mesh in the middle layer, and a polypropylene monofilament filter cloth in the outer layer.

5. The stacked high-pressure control method for sludge dewatering according to claim 4, characterized in that, In the layered material laying process, the adjustable filter press basket adopts a modular design. The height of the side plate can be steplessly adjusted within the range of 100-300mm via a hydraulic adjustment device to meet the needs of different layering quantities.

6. The stacked high-pressure control method for sludge dewatering according to claim 5, characterized in that, In multi-stage pressing, the dual-piston pressing mechanism adopts a hydraulic servo control system with a pressure control accuracy of ±0.5T, and the pressure curves of the upper and lower pistons can be independently programmed and controlled.

7. The stacked high-pressure control method for sludge dewatering according to claim 6, characterized in that, In drainage control, the ultrasonic thickness measuring device adopts a multi-probe array arrangement, with 3 to 5 thickness measuring points set for each filter press unit, and the measurement accuracy reaches ±0.1mm.

8. The stacked high-pressure control method for sludge dewatering according to claim 7, characterized in that, It also includes unloading and filter cloth regeneration: after pressing, the dewatered sludge cake is separated, and the filter cloth is recycled after being washed with high-pressure water and ultrasonically cleaned.

9. The stacked high-pressure control method for sludge dewatering according to claim 8, characterized in that, It also includes the subsequent treatment of sludge cake: the dewatered sludge cake is crushed to a particle size of 2-5mm, 5%-10% of biomass additives are added, and it is dried at a low temperature of 50-65℃ to produce organic fertilizer products.

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