Sludge treatment method and system

Abstract

The invention discloses a sludge treatment method and system, and relates to the field of solid waste treatment, and the method specifically comprises the following operation steps: S1, multi-frequency resonance pretreatment: destroying a sludge colloid structure through stepped mechanical vibration: collapsing an extracellular polymer network at a low frequency, breaking down microbial cell walls at an intermediate frequency to release intracellular water, pathogenic bacteria are inactivated through a high-frequency cavitation effect; s2, performing electrochemical in-situ flocculation; s3, gradient pressure dehydration; s4, low-temperature mineralization stabilization; and S5, vacuum condensation and recovery. According to the sludge treatment method and system, through stepped low-frequency, medium-frequency and high-frequency mechanical resonance, the colloid structure of the sludge can be directionally damaged, the fluidity of the sludge is remarkably improved, chemical conditioners are remarkably reduced, agent residues and secondary pollution are avoided, pathogens are physically inactivated through the high-frequency cavitation effect, and the treatment effect of the sludge is improved. Micro-nano oxygen bubbles are synchronously generated to strengthen free radical oxidation, and a sterile environment is created for subsequent mineralization.

Description

Technical Field

[0001] The present invention relates to the field of solid waste treatment, and in particular to a sludge treatment method and system. Background Art

[0002] Sludge is solid sediment produced by water and sewage treatment processes.

[0003] Traditional sludge treatment technologies such as concentration and dehydration, anaerobic digestion, and thermal drying have three major bottlenecks:

[0004] Low dewatering efficiency: The sludge colloidal structure is stable, with hydrophilic extracellular polymers (EPS) accounting for 60%, and the moisture content is still 60-80% after mechanical dehydration; strong dependence on chemical agents: the amount of conditioner added is as high as 15-30% of the sludge dry weight, resulting in sludge increment and secondary pollution; high energy consumption: the energy consumption of thermal drying reaches 800-1000kWh / ton of water, and high temperature destroys the value of sludge organic matter resources.

[0005] Therefore, it is necessary to propose a sludge treatment method and system to solve the above problems. Summary of the Invention

[0006] The main purpose of the present invention is to provide a sludge treatment method and system, which can effectively solve the problems in the background technology.

[0007] To achieve the above object, the technical solution adopted by the present invention is:

[0008] A sludge treatment method comprises the following steps:

[0009] S1: Multi-frequency resonance pretreatment destroys the sludge colloidal structure through stepped mechanical vibration: low frequency disintegrates the extracellular polymer network, medium frequency breaks through the microbial cell wall to release intracellular water, and high frequency cavitation effect inactivates pathogens.

[0010] S2: Electrochemical in-situ flocculation, under the action of DC electric field, the anode dissolves metal ions and HCO3 in the sludge - Combined with the generation of siderite crystal nuclei, cathode hydrogen evolution promotes floc floating, which is used to replace chemical agents to achieve zero-addition flocculation and simultaneously recover hydrogen energy.

[0011] S3: Gradient pressure dehydration uses three-level pressure progressive dehydration, including removing interstitial water, releasing capillary water, and breaking the bound water film by combining vibration shearing, which is used to break through the bottleneck of capillary water removal and achieve deep dehydration through mechanical force gradient to form peelable sludge particles.

[0012] S4: Low-temperature mineralization stability. Polyaspartic acid is added at 60°C to guide hydroxyapatite to crystallize on the sludge surface, encapsulate heavy metal ions and seal organic matter, which is used to solidify heavy metals at low temperatures and inhibit the decomposition of organic matter.

[0013] S5: Vacuum condensation recovery, the filtrate generated by gradient pressure dewatering is reduced in boiling point by vacuum flash evaporation, and water is vaporized at low temperature and then condensed and purified for recovery of process water up to standard, realizing closed-loop utilization of water resources.

[0014] Preferably, in S1, the following steps are specifically included:

[0015] S101: Prepare a multi-frequency resonance pretreatment reactor with three built-in resonance generators, the frequency range of the resonance generators is 20-100 kHz, and the power is adjustable from 0 to 50 kW;

[0016] S102: Sludge feeding control, the raw sludge with a moisture content of 99% is pumped into the multi-frequency resonance pretreatment reactor by a screw pump at a flow rate of 3.5 m 3 / h, and micro-nano oxygen bubbles are injected synchronously to enhance the cavitation oxidation effect;

[0017] S103: Start the resonance generator and run at low frequency to break glue, medium frequency to break cells, and high frequency to inactivate, specifically:

[0018] Low-frequency glue breaking: 0-5 min, 20 kHz low-frequency resonance is used, the amplitude is 50 μm, and it is used to destroy the EPS colloidal network;

[0019] Medium-frequency cell breaking: 5-10 min, 60 kHz medium-frequency resonance is used, the amplitude is 20 μm, and it is used to break the microbial cell wall;

[0020] High-frequency inactivation: 10-15 min, 100 kHz high-frequency resonance is used, the amplitude is 5 μm, and it is used to inactivate pathogenic bacteria;

[0021] After the operation is completed, it is discharged.

[0022] Preferably, in S2, the following steps are specifically included:

[0023] S201: Prepare an electrochemical in-situ flocculation conditioning tank, which includes an anode: a soluble cast iron plate, a cathode: a titanium-coated ruthenium mesh plate with a pore size of 5 mm, and a direct current power supply voltage adjustable from 0 to 12 V;

[0024] S202: Electrochemical reaction control, the sludge pretreated in S1 is flowed into the electrochemical in-situ flocculation conditioning tank, the residence time is 25 min, the current density is controlled at 15 A / m 2 , and the flow rate in the tank is 0.2 m / s; wherein the anode reaction is Fe→Fe 2+ +2e - ; the cathode reaction is 2H2O+2e - →H2+2OH - ;

[0025] S203: In situ mineral floc formation, HCO3 in sludge - with Fe 2+ Combined to form siderite nuclei, while OH - Promoting some Fe 2+ Oxidized to FeOOH colloid, forming a composite flocculation skeleton of FeCO3-FeOOH;

[0026] S204: Hydrogen recovery and utilization: the hydrogen generated at the cathode is collected and fed into the fuel cell system to generate electricity.

[0027] Preferably, said S3 includes the following steps:

[0028] S301: Prepare equipment for three-stage pressure progressive dewatering, including a gradient filter press dewatering unit, which is composed of a pre-pressing belt dewatering section with a belt width of 1.2m and a line pressure of 0.3MPa, a medium-pressure elastic filter press section with an elastic filter plate compression rate of 40%, and a high-pressure shear pressing section with a maximum pressure of 5.0MPa, wherein the pre-pressing belt dewatering section includes a polyester filter belt and a pre-pressing roller group, the medium-pressure elastic filter press section includes an elastic filter press chamber and elastic filter plates with a hydraulic system, and the high-pressure shear pressing section includes a shear pressing chamber, an upper pressing plate, and a lower pressing plate;

[0029] S302: Pre-pressing belt dewatering section, the sludge after flocculation in S2 is laid on the polyester filter belt of the pre-pressing belt dewatering section and squeezed by the pre-pressing roller group for 3 minutes;

[0030] S303: Medium-pressure elastic filter press section, where the sludge treated in S302 enters the elastic filter press chamber, and the hydraulic system pushes the elastic filter plate to compress; first stage: 0.5MPa pressure is maintained for 2 minutes to discharge interstitial water; second stage: 1.2MPa pressure is maintained for 3 minutes to release capillary water;

[0031] S304: High-pressure shearing and pressing section. After medium-pressure dehydration, the sludge is transferred to the shearing and pressing chamber. The upper pressing plate applies a static pressure of 2.0 MPa, while the lower pressing plate vibrates at a frequency of 1 Hz and an amplitude of 2 mm to destroy the bound water film. At this time, the sludge forms irregular particles.

[0032] Preferably, the step S4 specifically includes the following steps:

[0033] S401: Prepare a low-temperature mineralization stabilization tank and a fluidized bed cooler. The low-temperature mineralization stabilization tank is a horizontal rotating tank lined with a quartz sand wear-resistant layer, equipped with an infrared radiation heater, a mineralizer atomizing nozzle, and a vibrating screen with a pore size of 5 mm.

[0034] S402: Mineralization agent addition and mixing, the dewatered sludge particles treated by S3 are transported to a low-temperature mineralization stabilization tank, a biomimetic mineralization induction liquid, which is 0.1 mol of LCaCl2, 0.05 mol of LNa2HPO4 and 1% of polyaspartic acid, is sprayed through a mineralization agent atomizing nozzle, the addition amount is 8 L / ton of dry sludge, the low-temperature mineralization stabilization tank rotates at a speed of 5 rpm, and the mixing time is 40 min;

[0035] S403: The infrared radiation heater is turned on, the temperature is raised to 60 DEG C, and Ca 2+ is guided by polyaspartic acid to react with PO4 3- to generate hydroxyapatite microcrystals on the surface of the sludge particles, and the following changes occur at the same time:

[0036] Heavy metal encapsulation: Cd 2+ , Pb 2+ replace Ca 2+ into the crystal lattice, and the leakage concentration is less than 0.1 mg / L;

[0037] Organic matter stabilization: the hydroxyapatite microcrystals wrap the organic matter, inhibit microbial decomposition, and complete mineralization based on this;

[0038] S404: Product cooling and screening, the mineralized sludge is cooled to 35 DEG C through a fluidized bed cooler, and the qualified particles are separated through a vibrating screen, and the unqualified particles are returned to the low-temperature mineralization stabilization tank.

[0039] Preferably, in S5, the following steps are specifically included:

[0040] S501: A vacuum condensation recovery unit is prepared, which includes a tube condenser, a vacuum pump with a limit vacuum degree of -0.098 MPa, a condensate tank and a vacuum flash chamber;

[0041] S502: Vacuum flash of dewatering filtrate, the filtrate generated by gradient pressure dewatering enters the vacuum flash chamber, water is boiled and vaporized at 38 DEG C ± 2, and the steam enters the tube condenser through a flow guide pipe.

[0042] S503: Condensed water is upgraded and reused, the steam exchanges heat with cooling water at 20 DEG C in the tube condenser, and can be reused as plant greening water or equipment flushing water.

[0043] A sludge treatment system includes a multi-source sensor cooperative monitoring module, an adaptive decision control module and a distributed execution linkage module, and the multi-source sensor cooperative monitoring module includes:

[0044] An ultrasonic suspended solid sensor is installed at the outlet of a multi-frequency resonance pretreatment reactor, and real-time monitoring of sludge solid content is realized through the ultrasonic attenuation principle, and the range covers 1%-30% of suspended solid concentration;

[0045] Multi-parameter integrated probe: integrated temperature, viscosity, Zeta potential, heavy metal concentration, HCO3 - Concentration sensor data monitoring function, which is embedded in the electrochemical in-situ flocculation conditioning tank and low-temperature mineralization stabilization tank;

[0046] Vibration state sensor: A piezoelectric accelerometer is installed on the base of the multi-frequency resonance pretreatment reactor to monitor amplitude deviation and frequency stability in real time;

[0047] When the sludge enters the multi-frequency resonance pretreatment reactor, the ultrasonic sensor dynamically feeds back changes in solid content, triggering adaptive adjustment of the resonance frequency; the multi-parameter integrated probe in the electrochemical in-situ flocculation conditioning tank collects Zeta potential data every 30 seconds, and automatically reduces the current density when the potential is greater than -10mV to prevent excessive flocculation. When the vibration sensor detects an amplitude fluctuation of greater than 10%, it sends a resonance generator correction instruction to the adaptive decision control module and simultaneously triggers an audible and visual alarm.

[0048] Preferably, the adaptive decision control module includes multi-frequency resonance parameter adaptation, electrochemical mineralization coordinated regulation and machine learning optimization engine, and the machine learning optimization engine is an LSTM neural network model, wherein the multi-frequency resonance parameter adaptation: based on real-time viscosity data, dynamically matches the switching time of low-frequency gel breaking, medium-frequency cell fragmentation, and high-frequency inactivation, and the LSTM neural network model outputs the optimal oxygen bubble injection amount, and the formula is:

[0049]

[0050] Where η is the viscosity; is the oxygen bubble injection flow rate; ln is the natural logarithm function; 0.3 is the empirical coefficient;

[0051] Coordinated regulation of electrochemical mineralization: based on HCO3 - The concentration sensor data is used to calculate the current density according to the formula:

[0052]

[0053] Where k is the adaptive coefficient, ranging from 10-20A / m 2 ; when Fe 2+ When the concentration exceeds 300mg / L, the anode power supply will be automatically cut off to prevent electrode passivation; when HCO3 - =250mg / L, k is 15, then I = 3750A / m 2 , Fe 2+ The dissolution rate is precisely matched to the mineralization demand; when HCO3 - When the concentration of HCO3 is less than 100mg / L, k is reduced to 10 to save energy. - When the concentration is greater than 600 mg / L, k increases to 20 to accelerate the reaction.

[0054] Preferably, the distributed execution linkage module is used to control the gradient filter press dewatering unit and the low-temperature mineralization stabilization tank, specifically the pre-pressing belt dewatering section: the filter belt tension is adjusted according to the sludge solid content data, and when the solid content is less than 5%, it is reduced to 0.2MPa to prevent sludge from running away; the high-pressure shearing section: the phase difference between the vibration pressing and the static pressure is calculated in real time by the PLC to ensure the efficient rupture of the combined water film; the multi-parameter integrated probe detects Pb 2+ When the concentration is greater than 20 mg / kg, increase the polyaspartic acid addition rate by 15% and extend the crystallization time by 10 min.

[0055] Compared with the prior art, the present invention provides a sludge treatment method and system, which has the following beneficial effects:

[0056] 1. This sludge treatment method and system can directionally destroy the colloidal structure of sludge through stepped low-frequency, medium-frequency, and high-frequency mechanical resonance, significantly improve sludge fluidity, significantly reduce chemical conditioning agents, avoid drug residues and secondary pollution, physically inactivate pathogens through high-frequency cavitation effect, and simultaneously generate micro-nano oxygen bubbles to enhance free radical oxidation, creating a sterile environment for subsequent mineralization.

[0057] 2. The sludge treatment method and system, anode dissolution of Fe 2+ Endogenous HCO3 in sludge - The siderite nucleus is generated by the cathode hydrogen evolution, and the flocculent body floats up, thus realizing the construction of the flocculent skeleton without exogenous iron salt. The addition of polyaspartic acid can induce the heterogeneous crystallization of hydroxyapatite, and Cd 2+ , Pb 2+ Heavy metal ions such as ions are encapsulated in the mineral lattice, and their concentration is reduced.

[0058] 3. This sludge treatment method and system, through the coordinated effects of pre-pressure to remove interstitial water, medium-pressure to release capillary water, and high-pressure vibration to break up bound water, can overcome the bottleneck of mechanical dehydration and form sludge particles with high solid content. The mineralized particles after sludge treatment have the compressive strength of roadbed filler level and soil improvement activity, which can realize the value-added transformation of sludge from waste to building materials and improvers.

[0059] 4. This sludge treatment method and system can integrate real-time sensor data such as viscosity, Zeta potential, and ion concentration, and dynamically adjust the resonance frequency and current density through the LSTM model. Based on this, it can break through the rigid limitations of traditional PLC preset programs and has the ability to automatically dispatch multiple energy sources such as resonance power generation, hydrogen fuel electricity, and waste heat recovery to achieve self-balancing system energy consumption and reduce chemical and water resource consumption from the source. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] Figure 1 It is a flow chart of the present invention. DETAILED DESCRIPTION

[0061] In order to make the technical means, creative features, objectives and effects achieved by the present invention easier to understand, the present invention is further described below in conjunction with specific implementation methods.

[0062] Example 1:

[0063] like Figure 1 As shown, a sludge treatment method includes the following steps:

[0064] S1: Multi-frequency resonance pretreatment destroys the sludge colloidal structure through stepped mechanical vibration: low frequency breaks down the extracellular polymer network, medium frequency breaks through the microbial cell wall to release intracellular water, and high frequency cavitation effect inactivates pathogens. Specifically, it includes the following steps:

[0065] S101: Prepare a multi-frequency resonance pretreatment reactor with three built-in resonance generators, the frequency range of the resonance generator is 20-100kHz, and the power is adjustable from 0-50kW;

[0066] S102: Sludge feed control: the original sludge with a moisture content of 99%, here municipal mixed sludge, COD 12,000-15,000 mg / L and viscosity 50-60 MPa·s, is pumped into the sludge feed at a speed of 3.5 m 3 / h flow rate pumped into the multi-frequency resonance pretreatment reactor, and simultaneously injected with a diameter of 50-100μm and a flow rate of 0.5m 3 / h of micro-nano oxygen bubbles to enhance the cavitation oxidation effect. When the viscosity is 60MPa·s, the low-frequency gel breaking is extended to 8min.

[0067] S103: Start the resonance generator and operate according to the low-frequency gel breaking, medium-frequency cell fragmentation, and high-frequency inactivation. Specifically:

[0068] Low-frequency gel breaking: 0-5min, using 20kHz low-frequency resonance, amplitude 50μm, to destroy the EPS gel network;

[0069] Medium frequency cell disruption: 5-10 minutes, using 60kHz medium frequency resonance and 20μm amplitude to break through the cell wall of microorganisms;

[0070] High-frequency inactivation: 10-15 minutes, using 100kHz high-frequency resonance and 5μm amplitude to inactivate pathogens;

[0071] After the operation is completed, it will be discharged. The outlet sludge capillary water absorption time is ≤30s, the viscosity is ≤40MPa·s, and the pathogen inactivation rate is ≥99.9% according to GB18466-2005 test;

[0072] A piezoelectric ceramic ring is installed on the outer wall of the multi-frequency resonance pretreatment reactor to convert mechanical vibration energy into electrical energy and feed it back to the power grid. After S1 treatment, the moisture content of the sludge is 98%.

[0073] S2: Electrochemical in-situ flocculation, under the action of DC electric field, the anode dissolves metal ions and HCO3 in the sludge - Combined with the generation of siderite crystal nuclei, cathode hydrogen evolution promotes floc floating, which is used to replace chemical agents to achieve zero-addition flocculation and simultaneously recover hydrogen energy. The specific steps include:

[0074] S201: Prepare an electrochemical in-situ flocculation conditioning tank, which includes an anode: a soluble cast iron plate with Fe ≥ 98.5% and C ≤ 0.1%, a typical operating voltage of 8V, a cathode: a titanium-coated ruthenium mesh plate with a pore size of 5mm, and a DC power supply voltage adjustable from 0-12V;

[0075] S202: Electrochemical reaction control, the sludge pretreated by S1 flows into the electrochemical in-situ flocculation conditioning tank, the residence time is 25 minutes, and the current density is controlled at 15A / m 2 , the flow rate in the tank is 0.2m / s; the anode reaction is: Fe→Fe 2+ +2e - ; Cathode reaction: 2H2O+2e - →H2+2OH - ;

[0076] S203: In situ mineral floc formation, HCO3 in sludge - with Fe 2+ Combined to form siderite nuclei with a particle size of 1–3 μm, and OH - Promoting some Fe 2+ Oxidized to FeOOH colloid, forming a composite flocculation skeleton of FeCO3-FeOOH, reducing the sludge resistance to 5×10 11 m / kg, the Zeta potential increased from -25mV to -5mV, at which time the sludge COD dropped below 8,000mg / L;

[0077] S204: Hydrogen recovery and utilization: the hydrogen generated at the cathode is collected and fed into the fuel cell system to generate electricity.

[0078] S3: Gradient pressure dehydration uses three-level pressure progressive dehydration, including removing interstitial water, releasing capillary water, and breaking the bound water film by vibration shearing. It is used to break through the bottleneck of capillary water removal and achieve deep dehydration through mechanical force gradient to form peelable sludge particles. It includes the following steps:

[0079] S301: Prepare equipment for three-stage pressure progressive dewatering, including a gradient filter press dewatering unit, which consists of a pre-pressing belt dewatering section with a belt width of 1.2m and a line pressure of 0.3MPa, a medium-pressure elastic filter press section with an elastic filter plate compression rate of 40%, and a high-pressure shear press section with a compression rate measured according to ISO3386 and a maximum pressure of 5.0MPa, connected in series. The pre-pressing belt dewatering section includes a polyester filter belt and a pre-pressing roller assembly, the medium-pressure elastic filter press section includes an elastic filter press chamber and elastic filter plates with a hydraulic system, and the high-pressure shear press section includes a shear press chamber, an upper press plate, and a lower press plate.

[0080] S302: Pre-pressed belt dewatering section, the sludge after flocculation in S2 is laid on the polyester filter belt of the pre-pressed belt dewatering section, and squeezed by the pre-pressed roller group for 3 minutes. The opening rate of the polyester filter belt is ≥45%, and the water permeability is ≥5m 3 / (m 2 h), the moisture content dropped from 98% to 85%;

[0081] S303: Medium-pressure elastic filter press section, the sludge treated in S302 enters the elastic filter press chamber, and the hydraulic system pushes the elastic filter plate to compress; the first stage: 0.5MPa pressure is maintained for 2 minutes to discharge interstitial water; the second stage: 1.2MPa pressure is maintained for 3 minutes to release capillary water, at which time the moisture content is reduced to 65%, and the sludge becomes peelable sheets. When the moisture content of the sludge at the outlet of the pre-pressing belt dehydration section is ≤85%, the medium-pressure elastic filter press section is automatically started;

[0082] S304: High-pressure shear pressing section. After medium-pressure dehydration, the sludge is transferred to the shear pressing chamber. The upper pressing plate applies a static pressure of 2.0 MPa, while the lower pressing plate vibrates at a frequency of 1 Hz and an amplitude of 2 mm to destroy the bound water film. The final moisture content is ≤40%. At this time, the sludge forms irregular particles with a particle size of 3-8 mm and a compressive strength of >50 N / particle.

[0083] S4: Low temperature mineralization is stable. Polyaspartic acid is added at 60°C. It is a 1% aqueous solution with a molecular weight of 8,000-10,000. This guides the crystallization of hydroxyapatite on the sludge surface. The carboxyl groups (-COOH) on the polyaspartic acid molecular chain adsorb Ca through chelation. 2+ , forming a local calcium ion enrichment zone with a concentration of more than 3 times that of the bulk solution, reducing the activation energy of hydroxyapatite crystallization from 85kJ / mol to 70kJ / mol, inducing heterogeneous nucleation of crystals on the surface of sludge particles. Based on the Arrhenius equation, it is measured by differential scanning calorimetry (DSC), encapsulating heavy metal ions and sealing organic matter, and is used for low-temperature solidification of heavy metals and inhibition of organic matter decomposition. Specifically, it includes the following steps:

[0084] S401: Prepare a low-temperature mineralization stabilization tank and a fluidized bed cooler. The low-temperature mineralization stabilization tank is a horizontal rotating tank lined with a quartz sand wear-resistant layer. It is equipped with a 30kW infrared radiation heater with a temperature control accuracy of ±1°C, a mineralizer atomizing nozzle, and a vibrating screen with a 5mm aperture.

[0085] S402: Adding and mixing mineralizers: transporting the dehydrated sludge particles after S3 treatment to a low-temperature mineralization stabilization tank, spraying a biomimetic mineralization induction solution containing 0.1 mol LCaCl2, 0.05 mol LNa2HPO4, and 1% polyaspartic acid through a mineralizer atomizing nozzle, with an addition amount of 8 L / ton of dry sludge. The low-temperature mineralization stabilization tank rotates at 5 rpm for 40 minutes.

[0086] S403: Turn on the infrared radiation heater and raise the temperature to 60℃. Under the guidance of polyaspartic acid, Ca 2+ With PO4 3- Hydroxyapatite crystals are generated on the surface of sludge particles, and the following changes occur simultaneously:

[0087] Heavy metal package: Cd 2+ , Pb 2+ Replace Ca 2+ Entering the crystal lattice, the seepage concentration is less than 0.1mg / L, and the detection standard is GB5085.3;

[0088] Organic matter stabilization: Hydroxyapatite microcrystals coat organic matter, inhibiting microbial decomposition and thus completing mineralization;

[0089] S404: Product cooling and screening. The mineralized sludge is cooled to 35°C in a fluidized bed cooler, and the qualified particles are separated by a vibrating screen. The unqualified particles are returned to the low-temperature mineralization stabilization tank.

[0090] S5: Vacuum condensation recovery: The filtrate produced by gradient pressure dehydration is subjected to vacuum flash evaporation to reduce the boiling point. The water is vaporized at low temperature and then condensed and purified to recover qualified process water, realizing closed-loop utilization of water resources. The specific steps include:

[0091] S501: Prepare a vacuum condensation recovery unit, which includes a shell-and-tube condenser, a vacuum pump with an ultimate vacuum degree of -0.098 MPa, a condensate tank, and a vacuum flash chamber;

[0092] S502: Dehydrated filtrate is vacuum flashed. The filtrate produced by gradient pressure dehydration enters the vacuum flash chamber. The filtrate COD is ≤500mg / L, and the conductivity is ≤5mS / cm. The vacuum flash temperature is set to 38℃±2. The water boils and vaporizes at 38℃±2. The steam enters the shell and tube condenser through the draft tube. The dehydrated filtrate is tested: COD423mg / L, Cl -1200mg / L, calculated according to Dühring rule, the boiling point is 38.2℃ under 250mmHg (-0.098MPa) vacuum, and the measured vaporization temperature is 37.8-39.1℃;

[0093] S503: Condensate is upgraded and reused. Steam exchanges heat with 20°C cooling water in a shell-and-tube condenser. The condensate has a COD of ≤30mg / L and NH3-N of ≤5mg / L. It can then be reused as water for plant greening or equipment flushing.

[0094] Example 2:

[0095] A sludge treatment system includes a multi-source sensor collaborative monitoring module, an adaptive decision control module, and a distributed execution linkage module. The multi-source sensor collaborative monitoring module includes:

[0096] Ultrasonic suspended solids sensor: installed at the outlet of the multi-frequency resonance pretreatment reactor, it monitors the solid content of sludge in real time through the principle of ultrasonic attenuation, with a range covering 1%-30% suspended solids concentration;

[0097] Multi-parameter integrated probe: integrated temperature: Pt100 thermocouple, viscosity: rotational viscometer, Zeta potential: electrophoretic mobility sensor, heavy metal concentration: ion selective electrode, HCO3 - Concentration sensor data monitoring function, which is embedded in the electrochemical in-situ flocculation conditioning tank and low-temperature mineralization stabilization tank;

[0098] Vibration state sensor: A piezoelectric accelerometer is installed on the base of the multi-frequency resonance pretreatment reactor to monitor amplitude deviation and frequency stability in real time;

[0099] When the sludge enters the multi-frequency resonance pretreatment reactor, the ultrasonic sensor dynamically feeds back changes in solid content, triggering adaptive adjustment of the resonance frequency. For example, when the solid content is greater than 8%, it switches to a 60kHz medium frequency cell breaking mechanism. The multi-parameter integrated probe in the electrochemical in-situ flocculation conditioning tank collects Zeta potential data every 30 seconds. When the potential is greater than -10mV, the current density is automatically reduced to prevent excessive flocculation. When the vibration sensor detects an amplitude fluctuation greater than 10%, it sends a resonance generator correction instruction to the adaptive decision control module, and simultaneously triggers an audible and visual alarm.

[0100] The adaptive decision-making control module includes multi-frequency resonance parameter adaptation, electrochemical mineralization coordinated regulation, and a machine learning optimization engine. The machine learning optimization engine is an LSTM neural network model. The training data comes from the mapping relationship between 100,000 sets of sludge parameters and dewatering effects under historical operating conditions. The input parameters include viscosity, solid content, and other features used in sewage treatment. After 5-fold cross-validation, the error is ≤4.2%. The LSTM neural network model includes 1 input layer (12 neurons), 2 hidden layers (64 neurons per layer, tanh activation function), and 1 output layer (linear activation). It uses the Adam optimizer with a learning rate of 0.001. The multi-frequency resonance parameter adaptation: Based on real-time viscosity data, it dynamically matches the switching time of low-frequency gel breaking, medium-frequency cell fragmentation, and high-frequency inactivation. For example, when the viscosity is greater than 50 MPa·s, the low-frequency gel breaking is extended to 7 minutes. The LSTM neural network model outputs the optimal oxygen bubble injection rate. The formula is:

[0101]

[0102] Where η is the viscosity; is the oxygen bubble injection flow rate; ln is the natural logarithm function; 0.3 is the empirical coefficient, which is obtained by fitting 100,000 sets of data through LSTM neural network model training to optimize the balance between oxidation efficiency and energy consumption. When η increases from 30MPa·s to 80MPa·s, From 1.0m 3 / h increased to 1.8m 3 / h, EPS degradation rate increased by 40%, when η<10MPa·s, Take the minimum value of 0.5m 3 / h;

[0103] Coordinated regulation of electrochemical mineralization: based on HCO3 - The concentration sensor data is used to calculate the current density according to the formula:

[0104]

[0105] Where k is the adaptive coefficient, ranging from 10-20A / m 2 When sludge COD = 10,000 mg / L, k = 15; when COD> 15,000 mg / L, k = 20; when Fe 2+ When the concentration exceeds 300 mg / L, the anode power supply is automatically cut off and the Fe 2+ The concentration is detected to prevent electrode passivation; when HCO3 - =250mg / L, k is 15, then I = 3750A / m 2 , Fe 2+ The dissolution rate is precisely matched to the mineralization demand; when HCO3 -When the concentration of HCO3 is less than 100mg / L, k is reduced to 10 to save energy. - When the concentration is greater than 600 mg / L, k increases to 20 to accelerate the reaction.

[0106] The distributed execution linkage module is used to control the gradient filter press dewatering unit and the low-temperature mineralization stabilization tank. Specifically, the pre-pressing belt dewatering section adjusts the filter belt tension according to the sludge solid content data. When the solid content is less than 5%, it is reduced to 0.2MPa to prevent sludge leakage; the high-pressure shearing section calculates the phase difference between the vibration pressing and the static pressure in real time by the PLC to ensure the efficient rupture of the combined water film; the multi-parameter integrated probe detects Pb 2+ When the concentration is greater than 20 mg / kg, increase the polyaspartic acid addition rate by 15% and extend the crystallization time by 10 min.

[0107] Example 3:

[0108] The performance of the sludge treatment technology of the present invention is compared with that of the traditional technology. The following is a comparison table:

[0109]

[0110]

[0111] Based on this, the present invention destroys the colloidal structure in a direction through multi-frequency resonance, specifically destroying EPS at low frequency and killing pathogens at high frequency, thus completely avoiding flocculant residues.

[0112] The basic principles, main features, and advantages of the present invention are shown and described above. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention. Such changes and modifications are intended to fall within the scope of the present invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A sludge treatment method, characterized in that: The following steps are included: S1: Multi-frequency resonance pretreatment, which destroys the sludge colloidal structure through stepped mechanical vibration: low frequency disintegrates the extracellular polymer network, medium frequency breaks through the microbial cell wall to release intracellular water, and high frequency cavitation effect inactivates pathogens; S2: Electrochemical in-situ flocculation, under the action of DC electric field, the anode dissolves metal ions and HCO3 in the sludge - Combined with the formation of siderite crystal nuclei, cathode hydrogen evolution promotes floc floating, which can be used to replace chemical agents to achieve zero-addition flocculation and simultaneously recover hydrogen energy; S3: Gradient pressure dehydration uses three-level pressure progressive dehydration, including removing interstitial water, releasing capillary water, and breaking the bound water film by vibration shearing. This is used to break through the bottleneck of capillary water removal and achieve deep dehydration through mechanical force gradient to form peelable sludge particles. S4: Low-temperature mineralization stabilization. Polyaspartic acid is added at 60°C to guide hydroxyapatite to crystallize on the sludge surface, encapsulating heavy metal ions and sealing organic matter, which is used to solidify heavy metals at low temperatures and inhibit the decomposition of organic matter. S5: Vacuum condensation recovery. The filtrate produced by gradient pressure dehydration is subjected to vacuum flash evaporation to reduce the boiling point. The water is vaporized at low temperature and then condensed and purified to recover qualified process water, realizing closed-loop utilization of water resources.

2. A sludge treatment method according to claim 1, characterized in that: Said S1 specifically includes the following steps: S101: Prepare a multi-frequency resonance pretreatment reactor with three built-in resonance generators, the frequency range of the resonance generator is 20-100kHz, and the power is adjustable from 0-50kW; S102: Sludge feed control, the original sludge with a moisture content of 99% is pumped through a screw pump at a speed of 3.5m 3 / h flow rate is pumped into the multi-frequency resonance pretreatment reactor, and micro-nano oxygen bubbles are injected synchronously to enhance the cavitation oxidation effect; S103: Start the resonance generator and operate according to the low-frequency gel breaking, medium-frequency cell fragmentation, and high-frequency inactivation. Specifically: Low-frequency gel breaking: 0-5min, using 20kHz low-frequency resonance, amplitude 50μm, to destroy the EPS gel network; Medium frequency cell disruption: 5-10 minutes, using 60kHz medium frequency resonance and 20μm amplitude to break through the cell wall of microorganisms; High-frequency inactivation: 10-15 minutes, using 100kHz high-frequency resonance and 5μm amplitude to inactivate pathogens; Drain it after the run is complete.

3. A sludge treatment method according to claim 1, characterized in that: Said S2 specifically comprises the following steps: S201: prepare an electrochemical in-situ flocculation conditioning tank, which includes an anode: a soluble cast iron plate, a cathode: a titanium-coated ruthenium mesh plate with a pore size of 5 mm, and a DC power supply voltage adjustable from 0 to 12 V; S202: Electrochemical reaction control, the sludge pretreated by S1 flows into the electrochemical in-situ flocculation conditioning tank, the residence time is 25 minutes, and the current density is controlled at 15A / m 2 , the flow rate in the tank is 0.2m / s; the anode reaction is: Fe→Fe 2+ +2e - ; Cathode reaction: 2H2O+2e - →H2+2OH - ; S203: In situ mineral floc formation, HCO3 in sludge - with Fe 2+ Combined to form siderite nuclei, while OH - Promoting some Fe 2+ Oxidized to FeOOH colloid, forming a composite flocculation skeleton of FeCO3-FeOOH; S204: Hydrogen recovery and utilization: the hydrogen generated at the cathode is collected and fed into the fuel cell system to generate electricity.

4. A sludge treatment method according to claim 1, characterized in that: The S3 includes the following steps: S301: Prepare equipment for three-stage pressure progressive dewatering, including a gradient filter press dewatering unit, which is composed of a pre-pressing belt dewatering section with a belt width of 1.2m and a line pressure of 0.3MPa, a medium-pressure elastic filter press section with an elastic filter plate compression rate of 40%, and a high-pressure shear pressing section with a maximum pressure of 5.0MPa, wherein the pre-pressing belt dewatering section includes a polyester filter belt and a pre-pressing roller group, the medium-pressure elastic filter press section includes an elastic filter press chamber and elastic filter plates with a hydraulic system, and the high-pressure shear pressing section includes a shear pressing chamber, an upper pressing plate, and a lower pressing plate; S302: Pre-pressing belt dewatering section, the sludge after flocculation in S2 is laid on the polyester filter belt of the pre-pressing belt dewatering section and squeezed by the pre-pressing roller group for 3 minutes; S303: Medium-pressure elastic filter press section, where the sludge treated in S302 enters the elastic filter press chamber, and the hydraulic system pushes the elastic filter plate to compress; first stage: 0.5MPa pressure is maintained for 2 minutes to discharge interstitial water; second stage: 1.2MPa pressure is maintained for 3 minutes to release capillary water; S304: High-pressure shearing and pressing section. After medium-pressure dehydration, the sludge is transferred to the shearing and pressing chamber. The upper pressing plate applies a static pressure of 2.0 MPa, while the lower pressing plate vibrates at a frequency of 1 Hz and an amplitude of 2 mm to destroy the bound water film. At this time, the sludge forms irregular particles.

5. A sludge treatment method according to claim 4, characterized in that: The S4 specifically includes the following steps: S401: Prepare a low-temperature mineralization stabilization tank and a fluidized bed cooler. The low-temperature mineralization stabilization tank is a horizontal rotating tank lined with a quartz sand wear-resistant layer, equipped with an infrared radiation heater, a mineralizer atomizing nozzle, and a vibrating screen with a pore size of 5 mm. S402: Adding and mixing mineralizers: transporting the dehydrated sludge particles after S3 treatment to a low-temperature mineralization stabilization tank, spraying a biomimetic mineralization induction solution containing 0.1 mol LCaCl2, 0.05 mol LNa2HPO4, and 1% polyaspartic acid through a mineralizer atomizing nozzle, with an addition amount of 8 L / ton of dry sludge. The low-temperature mineralization stabilization tank rotates at 5 rpm for 40 minutes. S403: Turn on the infrared radiation heater and raise the temperature to 60℃. Under the guidance of polyaspartic acid, Ca 2+ With PO4 3- Hydroxyapatite crystals are generated on the surface of sludge particles, and the following changes occur simultaneously: Heavy metal package: Cd 2+ , Pb 2+ Replace Ca 2+ Entering the crystal lattice, the seepage concentration is less than 0.1 mg / L; Organic matter stabilization: Hydroxyapatite microcrystals coat organic matter, inhibiting microbial decomposition and thus completing mineralization; S404: Product cooling and screening. The mineralized sludge is cooled to 35°C in a fluidized bed cooler, and the qualified particles are separated by a vibrating screen. The unqualified particles are returned to the low-temperature mineralization stabilization tank.

6. A sludge treatment method according to claim 1, characterized in that: The S5 specifically includes the following steps: S501: Prepare a vacuum condensation recovery unit, which includes a shell-and-tube condenser, a vacuum pump with an ultimate vacuum degree of -0.098 MPa, a condensate tank, and a vacuum flash chamber; S502: Vacuum flash evaporation of dehydrated filtrate. The filtrate produced by gradient pressure dehydration enters the vacuum flash chamber. The water boils and vaporizes at 38℃±2. The steam enters the shell-and-tube condenser through the draft tube. S503: Condensate is upgraded and reused. Steam exchanges heat with 20°C cooling water in a shell-and-tube condenser and can be reused as water for plant greening or equipment flushing.

7. A sludge treatment system, using a sludge treatment method according to any one of claims 1 to 6, comprising a multi-source sensor collaborative monitoring module, an adaptive decision control module, and a distributed execution linkage module, characterized in that: The multi-source sensor collaborative monitoring module includes: Ultrasonic suspended solids sensor: installed at the outlet of the multi-frequency resonance pretreatment reactor, it monitors the solid content of sludge in real time through the principle of ultrasonic attenuation, with a range covering 1%-30% suspended solids concentration; Multi-parameter integrated probe: integrated temperature, viscosity, Zeta potential, heavy metal concentration, HCO3 - Concentration sensor data monitoring function, which is embedded in the electrochemical in-situ flocculation conditioning tank and low-temperature mineralization stabilization tank; Vibration state sensor: A piezoelectric accelerometer is installed on the base of the multi-frequency resonance pretreatment reactor to monitor amplitude deviation and frequency stability in real time; When the sludge enters the multi-frequency resonance pretreatment reactor, the ultrasonic sensor dynamically feeds back changes in solid content, triggering adaptive adjustment of the resonance frequency; the multi-parameter integrated probe in the electrochemical in-situ flocculation conditioning tank collects Zeta potential data every 30 seconds, and automatically reduces the current density when the potential is greater than -10mV to prevent excessive flocculation. When the vibration sensor detects an amplitude fluctuation of greater than 10%, it sends a resonance generator correction instruction to the adaptive decision control module and simultaneously triggers an audible and visual alarm.

8. A sludge treatment system according to claim 7, characterized in that: The adaptive decision-making control module includes multi-frequency resonance parameter adaptation, electrochemical mineralization coordinated regulation and control, and a machine learning optimization engine. The machine learning optimization engine is an LSTM neural network model. The multi-frequency resonance parameter adaptation: based on real-time viscosity data, dynamically matches the switching time of low-frequency gel breaking, medium-frequency cell fragmentation, and high-frequency inactivation. The LSTM neural network model outputs the optimal oxygen bubble injection amount, and the formula is: Where η is the viscosity; is the oxygen bubble injection flow rate; ln is the natural logarithm function; 0.3 is the empirical coefficient; Coordinated regulation of electrochemical mineralization: based on HCO3 - The concentration sensor data is used to calculate the current density according to the formula: Where k is the adaptive coefficient, ranging from 10-20A / m 2 ; when Fe 2+ When the concentration exceeds 300mg / L, the anode power supply is automatically cut off to prevent electrode passivation; when HCO3 - =250mg / L, k is 15, then I = 3750A / m 2 , Fe 2+ The dissolution rate is precisely matched to the mineralization demand; when HCO3 - When the concentration of HCO3 is less than 100mg / L, k is reduced to 10 to save energy. - When the concentration is greater than 600 mg / L, k increases to 20 to accelerate the reaction.

9. A sludge treatment system according to claim 8, characterized in that: The distributed execution linkage module is used to control the gradient filter press dewatering unit and the low-temperature mineralization stabilization tank. Specifically, the pre-pressing belt dewatering section: the filter belt tension is adjusted according to the sludge solid content data, and when the solid content is less than 5%, it is reduced to 0.2MPa to prevent sludge from escaping; the high-pressure shearing section: the phase difference between the vibration pressing and the static pressure is calculated in real time by the PLC to ensure the efficient rupture of the combined water film; the multi-parameter integrated probe detects Pb 2+ When the concentration is greater than 20 mg / kg, increase the polyaspartic acid addition rate by 15% and extend the crystallization time by 10 min.

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