Sludge multistage recycling system and closed-loop management method

Abstract

The invention discloses a sludge multistage recycling system and a closed-loop management method. An ultraviolet-visible light source is arranged in an anode chamber of a photocatalysis-bioelectrochemical pretreatment unit, a g-C3N4 / TiO2 heterojunction photocatalyst is loaded on the surface of an anode, and a Pd / Fe3O4 composite catalyst is loaded on a cathode; the microwave-plasma multistage mineralization unit comprises a quartz reaction cavity, a microwave emitter arranged at the top of the quartz reaction cavity, a plasma emitter arranged on the side wall of the quartz reaction cavity, and a permanent magnet roller arranged at an outlet; performing staged pyrolysis on organic matters, mineralizing intermediate products and performing targeted recovery on rare earth; and the block chain intelligent quality-grading module dynamically optimizes a quality-grading path through multi-modal sensing and an intelligent contract, and sends each component to a corresponding subsystem for resource conversion. According to the method, the sludge treatment efficiency and the recycling level are remarkably improved, and carbon emission and energy consumption are reduced.

Description

Technical Field

[0001] This invention relates to the fields of environmental engineering and resource recycling, and in particular to a multi-stage sludge resource utilization system and a closed-loop management method. Background Technology

[0002] With the acceleration of industrialization and urbanization, the problem of water body sediment pollution is becoming increasingly serious. As the main accumulation carrier of pollutants in water bodies, sediment contains a large amount of heavy metals (such as chromium, copper, lead, arsenic, and cadmium), persistent organic matter (such as polycyclic aromatic hydrocarbons and benzo(a)pyrene), pathogenic microorganisms, and sulfides, among other complex components. Untreated sediment not only causes continuous harm to the aquatic ecosystem through pollutant resuspension and release, but may also threaten human health through bioaccumulation in the food chain, and even lead to soil and groundwater pollution. Therefore, the harmless treatment and resource utilization of sediment has become an important issue for environmental governance and sustainable development.

[0003] Currently, sediment treatment mainly adopts a linear process of dewatering-solidification-building material utilization, but existing technologies have significant limitations: (1) Incomplete removal of pollutants: Traditional methods (such as composting and incineration) are inefficient at treating recalcitrant organic matter (such as antibiotics and microplastics) and emerging pollutants, and are prone to causing secondary pollution.

[0004] (2) Energy and resource waste: Existing resource utilization paths are mostly limited to biogas power generation or low-end building materials, and the conversion rate of high value-added products is insufficient.

[0005] (3) Limited level of intelligence: The existing system lacks dynamic traceability and data security, making it difficult to cope with complex and ever-changing sludge composition and market fluctuations. Summary of the Invention

[0006] To address the shortcomings of existing technologies, this invention proposes a multi-level sludge resource utilization system and a closed-loop management method. By combining photocatalytic synergy and blockchain intelligent control technology with bioelectrochemical enhancement and gradient mineralization, a closed-loop management system for multi-level sludge resource utilization and pollution control is achieved.

[0007] The specific technical solution is as follows: A multi-stage sludge resource utilization system includes: a photocatalytic-bioelectrochemical pretreatment unit, a microwave-plasma multi-stage mineralization unit, and a blockchain intelligent sludge separation module; The photocatalytic-bioelectrochemical pretreatment unit includes a dual-chamber reactor separated by transparent quartz glass. The sludge to be treated is introduced into the anode chamber, which is equipped with an ultraviolet-visible light source. The anode surface is loaded with a g-C3N4 / TiO2 heterojunction photocatalyst. The cathode chamber is injected with an acidic electrolyte containing Pd / Fe3O4 nanoparticles. The cathode adopts a three-dimensional graphene foam substrate with a Pd / Fe3O4 composite catalyst loaded on its surface. The microwave-plasma multi-stage mineralization unit includes: a quartz reaction chamber and a microwave transmitter arranged on its top, a plasma transmitter arranged on its sidewalls, and a permanent magnet drum at the outlet; a microwave sensitizer is added to the quartz reaction chamber, and organic matter and mineralization intermediate products are pyrolyzed in stages in the quartz reaction chamber by changing the power and frequency of the microwave transmitter and the plasma transmitter, and rare earth is recovered in a targeted manner; the permanent magnet drum is used to separate the products generated in each stage and input them into the blockchain intelligent mineralization module; The blockchain-based intelligent sludge separation module dynamically optimizes the sludge separation path through multimodal sensing and smart contracts. The optimized sludge separation path sends each component in the mineralized sludge to the corresponding subsystem for resource conversion.

[0008] Furthermore, the g-C3N4 / TiO2 heterojunction is prepared by melamine thermal polymerization and atomic layer deposition process; the Pd / Fe3O4 composite catalyst is synthesized by chemical reduction method, with magnetic saturation strength ≥45 emu / g and hydrogen evolution overpotential ≤98mV.

[0009] Furthermore, the quartz reaction chamber of the microwave-plasma multi-stage mineralization unit is lined with a polytetrafluoroethylene anti-corrosion layer. A pre-treated sludge inlet is provided at the upper end of the quartz reaction chamber for introducing the pre-treated sludge obtained from the photocatalytic-bioelectrochemical pre-treatment unit; and a mineralized sludge outlet is provided at the lower end for discharging the mineralized sludge obtained from the microwave-plasma multi-stage mineralization unit.

[0010] Furthermore, the microwave sensitizer has a Fe3O4@SiO2 core-shell structure and is added at a rate of 1%-2% of the dry weight of the sludge.

[0011] Furthermore, the blockchain intelligent sorting module is built on a private chain architecture based on Hyperledger Fabric, integrating a multimodal sensing terminal, a pneumatic-magnetic coupling sorting machine, and a robot grasping system, and dynamically optimizes the sorting path through smart contracts; The integrated multimodal sensing terminal uses X-ray fluorescence spectroscopy, laser-induced breakdown spectroscopy, and near-infrared-La Mans combined technology to detect the content and form of heavy metals, rare earth elements, and organic pollutants in sludge in real time. The pneumatic-magnetic-electric coupling separator includes a high-pressure cyclone, a superconducting magnetic separator, and a dielectric separation unit; the high-pressure cyclone is used to separate organic matter and slag based on density differences; the superconducting magnetic separator is used to target and adsorb rare-earth magnetic particles; and the dielectric separation unit is used to separate silicon-aluminum and phosphorus components based on differences in dielectric constants. The robotic grasping system is built based on the YOLOv7 visual model and is used to feed organic matter into the supercritical water gasification hydrogen production subsystem to obtain high-purity hydrogen; feed rare earth magnetic particles into the rare earth recovery subsystem to output high-purity rare earth; and feed silicon, aluminum and phosphorus components into the building material synthesis subsystem to synthesize negative carbon building materials or synthesize lithium iron phosphate precursors.

[0012] Furthermore, the blockchain-based intelligent grading module is simultaneously integrated with carbon trading and the supply chain, ensuring that data is tamper-proof and resources are traceable.

[0013] A closed-loop management method for multi-stage sludge resource utilization, based on the aforementioned multi-stage sludge resource utilization system, includes the following steps: S1: The sludge to be treated is input into the anode chamber. The anode loaded with photocatalyst is irradiated by an ultraviolet-visible light source, generating electron-hole pairs. The holes are responsible for oxidizing recalcitrant organic matter, while the electrons are transferred to the cathode chamber through an external circuit. In the cathode chamber, the electrons participate in the reaction to generate hydrogen gas and reduce heavy metal ions. At the same time, the facultative anaerobic bacteria in the anode chamber use the intermediate products generated by photocatalysis as a carbon source to further degrade pollutants. The released electrons are used to supplement the electrons generated by photocatalysis, forming a photo-biological synergy. S2: The pretreated sludge enters the quartz reaction chamber and a microwave sensitizer is added. During the reaction, the pretreated sludge is processed in three stages, including: pyrolysis of macromolecular organic matter, mineralization of small molecule intermediates, and promotion of rare earth oxide crystal phase recombination. Rare earth oxides are separated by magnetic separation through a permanent magnet drum, and then leached with dilute nitric acid and electrolytically deposited to obtain high-purity rare earth metals. S3: Real-time detection of sludge components through blockchain intelligent separation module, dynamic optimization of separation path, input of different components into different subsystems, and transformation of sludge into high-purity rare earth, high-purity hydrogen, lithium iron phosphate precursor and negative carbon building materials.

[0014] Furthermore, in S1, the illumination operation mode of the ultraviolet-visible light source includes a continuous illumination mode and an intermittent pulse mode to optimize light energy utilization efficiency; the continuous illumination mode is suitable for highly polluted sludge.

[0015] Furthermore, in step S2, the pretreated sludge is processed in three stages, including: Phase 1: During the first 0-15 minutes of operation in the quartz reaction chamber, microwaves dominate, with the microwave transmitter at 80% power. Microwaves selectively heat polar molecules in the sludge, causing the temperature inside the quartz reaction chamber to rise rapidly to 100-120℃, promoting the pyrolysis of organic matter. At the same time, non-thermal effects disturb chemical bonds, accelerating the chain breaking of perfluorinated compounds. Phase 2: 15-30 minutes after the quartz reaction chamber starts working, the power of the plasma emitter is increased to 70%. The dielectric barrier discharge plasma generator ionizes the Ar / O2 mixture to generate high-energy electrons, hydroxyl radicals and ozone, which drive the hydroxyl radicals to mineralize small molecule intermediates. Phase 3: 30-40 minutes after the quartz reaction chamber begins to operate, the microwave transmitter frequency is reduced to 1.8 GHz to promote the recombination of rare earth oxide crystal phases.

[0016] Furthermore, S3 is specifically implemented through the following sub-steps: (3.1) The composition of sludge is detected by a multimodal sensing terminal. The detection data is processed by edge computing nodes to generate a feature matrix, which is then transmitted to the blockchain decision center. (3.2) In the blockchain decision-making center, the smart contract dynamically optimizes the quality-separated path according to the multi-objective optimization function; the multi-objective optimization function is to maximize the sum of the product of resource recovery and the first weight coefficient, the product of total carbon emissions and the second weight coefficient, and the product of sustainability and the third weight coefficient; the resource recovery is the difference between the product of product unit price and output and processing cost, the total carbon emissions are the product of carbon emission factors of each link and processing volume, and the sustainability is calculated by combining rare earth recovery rate and hydrogen self-sufficiency rate; the first weight coefficient, the second weight coefficient, and the third weight coefficient are dynamically adjusted through reinforcement learning; (3.3) Based on the determined separation path, organic matter and slag are separated by density difference through high-pressure cyclone, rare earth magnetic particles are targeted adsorbed by superconducting magnetic separator, and silicon-aluminum and phosphorus components are separated by dielectric constant difference through dielectric separation unit. (3.4) The robot grasping system delivers each component to its corresponding subsystem for resource conversion: Organic matter is fed into a supercritical water gasification hydrogen production subsystem, which uses a Ni-Al2O3 catalyst to output high-purity hydrogen under conditions of temperature ≥374℃ and pressure ≥22.1MPa. Rare earth magnetic particles are fed into the rare earth recovery subsystem, where they are separated by magnetic separation and purified by acid washing to produce high-purity rare earth. The silicon-aluminum and phosphorus components are fed into the building material synthesis subsystem to synthesize negative carbon building materials or to synthesize lithium iron phosphate precursors. The loaded building materials are obtained by synthesizing calcite-type CaCO3 from silicon-aluminum-rich sludge and CO2 waste gas through a high-pressure mineralization reaction. The lithium iron phosphate precursors are obtained through a hydrothermal reaction of Li:Fe:P in a molar ratio of 1:1:1.

[0017] The beneficial effects of this invention are: (1) This invention significantly improves sludge treatment efficiency and resource utilization level through multi-technology synergy and intelligent control. The synergistic effect of photocatalysis and bioelectrochemistry greatly improves the degradation rate of microplastics and the removal rate of Cr(VI); the staged mineralization of microwave and plasma greatly improves the removal rate of antibiotics; through the blockchain intelligent separation module, sludge is accurately converted into lithium iron phosphate precursor, high-purity hydrogen and negative carbon building materials, which greatly improves economic benefits.

[0018] (2) The present invention reduces carbon emissions and energy consumption throughout the entire process, and generates hydrogen and supplies electricity simultaneously, realizing a closed loop of pollution control and resource recycling; it breaks through the traditional single mode and has high efficiency, intelligence and sustainability, providing an innovative solution for sludge treatment. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the multi-stage resource recovery system for sludge in an embodiment of the present invention.

[0020] Figure 2 This is a flowchart of the closed-loop management method for multi-level resource utilization of sludge in an embodiment of the present invention.

[0021] Figure 3 This is a flowchart of the pretreatment process performed by the photocatalytic-bioelectrochemical pretreatment unit in an embodiment of the present invention.

[0022] Figure 4 This is a flowchart of the graded mineralization process performed by the microwave-plasma multi-level mineralization unit in an embodiment of the present invention.

[0023] Figure 5 This is a flowchart of the blockchain intelligent grading module performing grading path transformation in an embodiment of the present invention.

[0024] In the figure, there are: photocatalytic-bioelectrochemical pretreatment unit 1, anode 1-1, cathode 1-2, anode chamber 1-3, cathode chamber 1-4, and transparent quartz glass 1-5; microwave-plasma multi-level mineralization unit 2, quartz reaction chamber 2-1, microwave transmitter 2-2, and plasma transmitter 2-3; and blockchain intelligent mineralization module 3. Detailed Implementation

[0025] The present invention will be described in detail below with reference to the accompanying drawings and preferred embodiments. The objectives and effects of the present invention will become clearer as a result. The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

[0026] This invention belongs to the field of environmental engineering and resource recycling technology. It addresses the problems of incomplete pollutant removal, low resource conversion rate and insufficient intelligence in sludge treatment. It proposes a multi-level sludge resource utilization system and closed-loop management method based on photocatalytic synergy and blockchain intelligent control. The system achieves efficient pollution control and resource recovery through the coordinated and phased treatment of each component, and realizes the utilization of resource products and data management.

[0027] like Figure 1 As shown, a multi-stage sludge resource utilization system includes: a photocatalytic-bioelectrochemical pretreatment unit 1, a microwave-plasma multi-stage mineralization unit 2, and a blockchain intelligent sludge separation module 3.

[0028] The photocatalytic-bioelectrochemical pretreatment unit 1 employs a dual-chamber reactor, comprising: anode 1-1, cathode 1-2, anode chamber 1-3, cathode chamber 1-4, and a translucent quartz glass 1-5. The translucent quartz glass 1-5 separates the anode chamber 1-3 from the cathode chamber 1-4. The anode chamber 1-3 is filled with sludge slurry (hereinafter referred to as the sludge to be treated) with a water content of 80%-85%, and contains an internal ultraviolet-visible light source (wavelength 200-600nm, power density 50-100mW / cm³). 2 The anode 1-1 has a g-C3N4 / TiO2 heterojunction photocatalyst (thickness ≤5μm) loaded on its electrode surface; the cathode chamber 1-4 is filled with an acidic electrolyte (pH=2.5-3.0) containing Pd / Fe3O4 nanoparticles; the cathode 1-2 is made of a three-dimensional graphene foam substrate with a Pd / Fe3O4 composite catalyst (particle size 10-20nm, Pd loading 1wt%) loaded on its surface.

[0029] Furthermore, the g-C3N4 / TiO2 heterojunction was prepared by melamine thermal polymerization (550℃) and atomic layer deposition, achieving a quantum efficiency ≥42% (under 450nm illumination) and maintaining an activity >95% after 50 cycles. The Pd / Fe3O4 composite catalyst was synthesized by chemical reduction, exhibiting a magnetic saturation strength ≥45 emu / g and a hydrogen evolution overpotential ≤98mV.

[0030] Photocatalysis-bioelectrochemical pretreatment unit 1 employs a g-C3N4 / TiO2 heterojunction photocatalyst to oxidize microplastics (C3N4 / TiO2) under UV-Vis excitation. 10 H 16 O4 degradation rate > 98%), electron-driven microbial electrolysis to produce hydrogen (purity 99.99%), and simultaneous reduction of Cr(VI) to stable Cr(III) (removal rate > 95%).

[0031] The pretreated sludge output from the photocatalytic-bioelectrochemical pretreatment unit 1 is input into the microwave-plasma multi-stage mineralization unit 2 for staged mineralization. The microwave-plasma multi-stage mineralization unit 2 includes: a quartz reaction chamber 2-1, a microwave emitter 2-2, and a plasma emitter 2-3. The cylindrical quartz chamber 2-1 is hollow and has a pressure resistance ≥2.0 MPa. This chamber serves as the core reactor and is lined with a polytetrafluoroethylene (PTFE) anti-corrosion layer. The upper end of the quartz reaction chamber 2-1 has a pretreated sludge inlet, and the lower end has a mineralized sludge outlet. A microwave sensitizer with a Fe3O4@SiO2 core-shell structure is added to the quartz reaction chamber 2-1 at a dosage of 1%-2% of the sludge dry weight to enhance microwave absorption and improve treatment efficiency. A microwave transmitter 2-2 (frequency 2.45 GHz, power 0-10 kW) is arranged on the top of the quartz reaction chamber 2-1, and a dielectric barrier discharge (DBD) plasma generator 2-3 (voltage 10-20 kV, frequency 5-20 kHz) is arranged on the side wall. By controlling the power and frequency of the microwave transmitter 2-2 and the power of the plasma transmitter 2-3, mineralization is carried out in stages in the quartz reaction chamber 2-1. A permanent magnet roller (magnetic field strength 1.2 T) is set at the outlet. The permanent magnet roller is used to initially separate the products generated in the three stages and input them into the blockchain intelligent separation module 3.

[0032] The microwave-plasma multi-level mineralization unit 2 combines microwave (2.45GHz) and dielectric barrier discharge plasma to pyrolyze organic matter (antibiotic removal rate >99%) and mineralization intermediates in stages, and to target and recover rare earth (La / Ce purity ≥99.95%).

[0033] The blockchain-based intelligent sludge sorting module 3, based on the Hyperledger Fabric platform, dynamically optimizes the sorting path through multimodal sensing and smart contracts. It sends each component in the mineralized sludge to the corresponding subsystem for resource conversion, accurately converting the sludge into lithium iron phosphate precursor (specific capacity 160mAh / g), high-purity hydrogen (yield 18L / kg), and carbon negative building materials (compressive strength 48MPa). It also connects to carbon trading and the supply chain to ensure data immutability and resource traceability.

[0034] Furthermore, the blockchain-based intelligent sludge sorting module 3 is built on a private chain architecture using Hyperledger Fabric. It integrates a multimodal sensing terminal, a pneumatic-magnetic coupling sorting machine (high-pressure cyclone 0.8-1.2MPa, superconducting magnetic separator with a 5T magnetic field, dielectric sorting unit), and a robotic grasping system (based on the YOLOv7 visual model). Through smart contracts, it dynamically optimizes the sludge sorting path, achieving precise sorting of sludge to rare earth recovery, lithium iron phosphate precursor synthesis, and supercritical water gasification hydrogen production subsystems for corresponding resource conversion. This realizes intelligent management of the entire sludge resource utilization process. The integrated multimodal sensing terminal uses X-ray fluorescence spectroscopy (XRF), laser-induced breakdown spectroscopy (LIBS), and near-infrared-La Mans combined technology to detect the content and form of heavy metals (As, Pb, Cd), rare earth elements (such as La, Ce), and organic pollutants (microplastics, antibiotics) in the sludge in real time.

[0035] This invention system achieves a comprehensive pollutant removal rate of >97%, a carbon emission reduction of 62%, and an economic benefit increase of 6 to 8 times through photo-electric-biological synergy, gradient mineralization, and blockchain intelligent regulation, providing a low-carbon and efficient closed-loop solution for the harmless treatment and high-value utilization of sludge.

[0036] Based on the aforementioned multi-stage sludge resource utilization system, this embodiment also proposes a closed-loop management method for multi-stage sludge resource utilization, using collaborative processing to achieve efficient pollution control and resource recovery, such as... Figure 2 As shown, the method includes the following steps: S1: Simultaneous degradation of microplastics (C) in the sludge to be treated via photocatalysis-bioelectrochemical pretreatment unit 1. 10 H 16 O4 degradation rate > 98% and reduction of Cr(VI) (removal rate > 95%), producing hydrogen (purity 99.99%). For example... Figure 3 As shown, the sludge to be treated is fed into anode chamber 1-3. In anode chamber 1-3, an ultraviolet-visible light source irradiates the anode 1-1 supported on a photocatalyst to generate electrons (e... - - Hole pairs (h + Holes are responsible for oxidizing recalcitrant organic matter, while electrons are transferred to cathode chambers 1-4 via an external circuit. In cathode chambers 1-4, electrons participate in the generation of hydrogen gas and the reduction of heavy metal ions. Simultaneously, facultative anaerobic bacteria (such as Geobacter) in anode chambers 1-3 utilize intermediate products (such as small molecule organic acids) generated by photocatalysis as a carbon source to further degrade pollutants. The released electrons can then replenish the electrons generated by photocatalysis, forming a "photo-biological" synergistic effect, achieving efficient pollutant degradation and resource recovery.

[0037] Key parameters of photocatalytic-bioelectrochemical pretreatment unit 1 include light intensity (50-100 mW / cm²). 2The pH (6.0-7.5) and hydraulic retention time (3-5 days) of anode chambers 1-3 are also considered. The UV-Vis light source can be set to either continuous illumination (suitable for highly polluted sludge) or intermittent pulse mode (light source is turned off every 10 minutes) to optimize light energy utilization efficiency.

[0038] Hole oxidation directly oxidizes recalcitrant organic matter in sludge, such as microplastics, antibiotics, and perfluorinated compounds (PFOA). Taking microplastics as an example, the degradation reaction formula is as follows: The generated electrons are transferred to cathode chambers 1-4 via an external circuit, driving the microbial electrolysis cell (MEC) to produce hydrogen. Electrons and protons (H+) react to form hydrogen. + They combine to produce hydrogen gas: Simultaneously, the Pd / Fe3O4 catalyst synergistically catalyzes the reduction of heavy metals (such as Cr(VI)) to a stable state (Cr(III)): The narrow bandgap (2.7 eV) of g-C3N4 loaded on the anode 1-1 surface broadened the photoresponse range (200-650 nm), while the high conductivity of TiO2 accelerated electron migration, resulting in an 80% improvement in electron transport efficiency compared to a single catalyst. In terms of material preparation, the g-C3N4 / TiO2 heterojunction was prepared via melamine thermal polymerization (550 °C) and atomic layer deposition (ALD) processes, achieving a quantum efficiency of 42% (under 450 nm illumination), and retaining >95% activity after 50 cycles. The Pd / Fe3O4 composite catalyst was synthesized via chemical reduction, exhibiting both magnetic recovery characteristics (recovery rate >98%) and high hydrogen evolution activity (overpotential as low as 98 mV).

[0039] S2: Organic matter is mineralized in two stages via a microwave-plasma multi-stage mineralization unit (antibiotic removal rate > 99%) and rare earth elements are recovered (La / Ce purity ≥ 99.95%). Figure 4 As shown, the pretreated sludge enters the quartz reaction chamber 2-1, and the microwave sensitizer Fe3O4@SiO2 is added. During the reaction, the microwave transmitter 2-2 and the plasma generator 2-3 work sequentially, processing the sludge in three stages: pyrolysis of macromolecular organic matter (such as sulfonamide antibiotics), mineralization of small molecule intermediates, and promotion of rare earth oxide (La2O3, CeO2) crystal phase recombination. Finally, the rare earth oxides (such as La2O3, CeO2) are magnetically separated by a permanent magnet drum, and then leached with dilute nitric acid (5% v / v) and electrolytically deposited to obtain high-purity (≥99.9%) rare earth metals.

[0040] The key operating parameters for the phased processing include: microwave power (5-8kW), plasma voltage (15-18kV), and reaction temperature (100-120℃).

[0041] Specifically, in stage one (0-15 min), microwaves dominate, with microwave transmitter 2-2 operating at 80% power. Microwaves selectively heat polar molecules (such as water and metal oxides) in the sludge, rapidly raising the temperature within the quartz reaction chamber 2-1 to 100-120°C, promoting the pyrolysis of organic matter. Simultaneously, non-thermal effects disrupt chemical bonds, accelerating the chain breakage of perfluorinated compounds (PFOA). The reaction formula is as follows: Phase Two (15-30 min): Plasma power is increased to 70%, mineralizing small molecule intermediates. DBD plasma generator 2-3 ionizes the Ar / O2 mixture (volume ratio 9:1), generating high-energy electrons, hydroxyl radicals (•OH), and ozone (O3), driving the mineralization of intermediates by •OH. Microwave transmitter 2-2 continues operation, microwave heating increasing the plasma electron density to 10-1. 15 cm -3 The free radical yield increases by 2-3 times, achieving deep oxidation of pollutants.

[0042] In Phase 3 (30-40 min), the microwave transmitter 2-2 is down-frequencyd to 1.8 GHz to promote the recombination of rare earth oxide crystal phases.

[0043] In terms of material design, a Fe3O4@SiO2 core-shell structure was used as a microwave sensitizer (addition amount 1%-2% of sludge dry weight). The Fe3O4 core (particle size 50nm) enhanced microwave absorption, while the SiO2 shell (thickness 5nm) inhibited Fe... 3+ Dissolution; CeO2 nanorods (200 nm in length) are loaded onto the surface of the discharge electrode inside the DBD plasma emitter 2-3 as a catalyst, and their Ce... 3+ / Ce 4+ The redox reaction promotes the generation of •OH, increasing the degradation rate of PFOA by 40%, improving the yield of hydroxyl radicals in the plasma treatment process, and enhancing the degradation efficiency of pollutants.

[0044] S3: The blockchain-based intelligent sludge separation module 3 monitors sludge components in real time, dynamically optimizes the separation path, and inputs different components into different subsystems, converting sludge into lithium iron phosphate precursors, high-purity hydrogen, and negative carbon building materials (compressive strength ≥48MPa). Simultaneously, the blockchain-based intelligent sludge separation module 3 ensures data security through multiple security mechanisms, achieves cross-chain collaboration, and enables carbon quota trading and resource flow tracking. For example... Figure 5 As shown, this method is implemented through the following sub-steps: (3.1) The sludge is first detected by a multimodal sensing terminal. The detection data is processed by an edge computing node (FPGA chip) to generate a feature matrix (≥100 dimensions) and then transmitted to the blockchain decision center.

[0045] (3.2) In the blockchain decision-making center, smart contracts dynamically optimize the fractional path based on a multi-objective optimization function.

[0046] The multi-objective optimization function embedded in smart contracts is: In the formula, Profit represents resource recovery revenue (resource recovery revenue = product unit price × output - processing cost); Carbon represents total carbon emissions (total carbon emissions = carbon emission factor of each stage × processing volume); and Sustainability represents sustainability, determined by the rare earth recovery rate R. rate With hydrogen self-sufficiency rate R h2 We obtain the weighted sum (with weight coefficient ω) as follows: The weight coefficients (α, β, γ) are dynamically adjusted through reinforcement learning (PPO algorithm) to satisfy α + β + γ = 1.

[0047] The PPO algorithm, based on a reinforcement learning framework, ensures training stability by limiting the policy update step size and optimizes the weight coefficients of resource recovery benefits, total carbon emissions, and sustainability in real time. For example, when rare earth prices fluctuate or carbon prices rise, the algorithm dynamically adjusts the weight coefficients to prioritize the scavenging paths: the weight of rare earth recycling automatically increases with rising market prices, driving high-rare-earth sludge to the targeted recycling line; for example, when the daily increase in rare earth prices exceeds 10%, high-rare-earth sludge is prioritized for recycling. When carbon prices exceed a threshold, the weight of high-carbon-emission processes is suppressed to reduce the system's carbon footprint; for example, when carbon prices exceed 200 yuan / ton, high-carbon-emission processes are restricted. Simultaneously, PPO is deeply integrated with blockchain, achieving cross-chain collaborative optimization through real-time interaction of supply chain data (such as VeChain rare earth transaction records) and carbon trading consortium blockchain information. This allows the scavenging strategy to capture real-time value while meeting dynamic environmental constraints.

[0048] One example of dynamically optimizing the separation path is as follows: when the As concentration is detected to be >50mg / kg, the emergency solidification channel is triggered. Ca(OH)2 is added to the independent emergency dosing reactor or pipeline after sorting and before entering each subsystem to generate calcium arsenate mineral (Ca3(AsO4)2), so that the As leaching concentration is ≤0.02mg / L, thereby achieving arsenic fixation.

[0049] (3.3) Based on the determined separation path, precise separation is achieved by a pneumatic-magnetic-electric coupling separator: a high-pressure cyclone (0.8-1.2MPa) separates organic matter and slag according to density differences; a superconducting magnetic separator (5T magnetic field) targets and adsorbs rare earth magnetic particles; and a dielectric separation unit separates silicon, aluminum and phosphorus components according to dielectric constant differences, with an accuracy of 95%.

[0050] (3.4) The robot grasping system sends each component into the corresponding subsystem for resource conversion.

[0051] Specifically, organic matter is fed into a supercritical water gasification hydrogen production subsystem. This subsystem uses a Ni-Al2O3 catalyst (particle size 50nm) and outputs high-purity hydrogen under conditions of temperature ≥374℃ and pressure ≥22.1MPa, with a hydrogen yield of 15-18L / kg sludge and a purity >99.99%.

[0052] Rare earth magnetic particles are fed into the rare earth recovery subsystem (magnetic separation + acid washing purification) to output high-purity rare earth with La / Ce purity ≥ 99.95%.

[0053] The silicon, aluminum, and phosphorus components are fed into the building material synthesis subsystem to synthesize negative carbon building materials or lithium iron phosphate precursors. Negative carbon building materials are obtained by synthesizing calcite-type CaCO3 from silicon-aluminum-rich sludge and CO2 waste gas through a high-pressure mineralization reaction (3.0 MPa, 60℃), achieving a compressive strength ≥45 MPa and replacing 30%-50% of cement. The lithium iron phosphate precursor synthesis route includes: reacting phosphorus-rich sludge with LiOH and FeSO4 in a hydrothermal reaction at 180℃ for 12 hours at a Li:Fe:P molar ratio of 1:1:1 to generate a lithium iron phosphate (LiFePO4 / C) precursor (specific capacity >155 mAh / g).

[0054] Furthermore, the blockchain decision-making hub consists of orderer nodes and peer nodes, and is encrypted using the national cryptographic algorithm SM2 to ensure decentralized trust between wastewater treatment plants, regulatory agencies, and enterprises.

[0055] Furthermore, in terms of security mechanisms, quantum-resistant signatures (NTRU algorithm) and zero-knowledge proofs (ZKP) are used to resist attacks. After the data is hashed by SHA-3 and put on the chain, consensus is reached through Byzantine Fault Tolerance (PBFT) to ensure that it is tamper-proof.

[0056] The invention is illustrated below with specific examples. A municipal wastewater treatment plant has a daily sludge treatment capacity of 100 tons. The sludge composition is complex, with the main pollutants including: heavy metals (Cr(VI) concentration 150 mg / kg, As concentration 80 mg / kg), microplastics (C... 10 H 16O4 (12 mg / kg), sulfonamide antibiotics (8 mg / kg), and rare earth elements (La content 0.3%, Ce content 0.2%). Traditional treatment technologies suffer from incomplete pollutant removal, low resource recovery rates, and high carbon emissions. To address these issues, the plant introduced a multi-stage sludge resource recovery system based on photocatalysis synergy and blockchain intelligent control. The treatment objectives are: a comprehensive pollutant removal rate ≥95%; simultaneous production of high-value-added resources (hydrogen, rare earth metals, lithium iron phosphate precursors); a 60% reduction in carbon emissions; and a 6-8 times increase in economic benefits.

[0057] In this embodiment, the photocatalytic-bioelectrochemical pretreatment unit 1 has a built-in ultraviolet-visible light source with a wavelength of 450 nm and a power density of 80 mW / cm². 2 The thickness of the g-C3N4 / TiO2 heterojunction photocatalyst supported on the surface of anode 1-1 is 5 μm. The sludge slurry input into anode chamber 1-3 has a water content of 85%, pH=7.0, and a hydraulic retention time of 4 days. The particle size of the Pd / Fe3O4 composite catalyst supported on the surface of cathode 1-2 is 15 nm. The pH of the acidic electrolyte in cathode chamber 1-4 is 2.8, and the Fe... 3+ The concentration was 0.2 mol / L. The photocatalytic reaction directly oxidized recalcitrant organic matter such as microplastics through holes. The generated electrons were transferred to cathode chambers 1-4 via an external circuit, driving microbial electrolysis to produce hydrogen and simultaneously reducing Cr(VI) to stable Cr(III). After pretreatment, the microplastic degradation rate was >98%, the Cr(VI) removal rate was >95%, the hydrogen purity reached 99.99%, and the power output was 0.7 kWh / m³. 3 sludge.

[0058] The microwave transmitter 2-2 operates at a frequency of 2.45 GHz, the DBD plasma generator 2-3 operates at a voltage of 18 kV, and the added Fe3O4@SiO2 microwave sensitizer is added at a concentration of 1.5% of the sludge dry weight. In the first stage, the microwave power is 8 kW, raising the temperature to 110℃ to pyrolyze large molecular organic matter. In the second stage, the plasma power is increased to 70%, mineralizing small molecule intermediates. In the third stage, the microwave frequency is reduced to 1.8 GHz to promote the recombination of rare earth oxide crystal phases. The mineralized residue is separated into rare earth oxides using a permanent magnet drum (magnetic field strength 1.2 T), followed by acid leaching (5% dilute nitric acid) and electrolytic deposition for purification, yielding La / Ce purity ≥99.95%. During operation, antibiotic removal rate >99%, PFOA degradation rate >98%, and rare earth recovery rate >90%.

[0059] The blockchain-based intelligent sludge sorting module 3 monitors sludge components in real time and dynamically optimizes the sorting path: For high-arsenic sludge, in this embodiment, As was detected at 60 mg / kg and phosphorus (P) content at 1.5%, triggering the emergency solidification channel. Ca(OH)2 was added to generate stable calcium arsenate minerals (Ca3(AsO4)2), with an As leaching concentration ≤0.02 mg / L. For phosphorus-rich sludge, lithium iron phosphate precursors were synthesized via hydrothermal reaction (180℃×12h) at a Li:Fe:P ratio of 1:1:1, with a specific capacity of 160 mAh / g. For organic residues, hydrogen was produced through supercritical water gasification (Ni-Al2O3 catalyst, 374℃, 22.1 MPa) with a yield of 18 L / kg and a purity of 99.99%. The sorting accuracy of the robotic grasping system is >95%. Simultaneous integration with the carbon trading alliance chain and the rare earth supply chain public chain enables automatic carbon quota trading and resource flow tracking, reducing carbon emissions by 62%.

[0060] In summary, the innovative points of this invention and its resulting technical effects are as follows: (1) This invention introduces the synergistic effect of ultraviolet-visible light catalysis and bioelectrochemistry, and the three-effect synergy of light-electricity-biology breaks through the bottleneck of single technology. The wide-spectrum material improves the light energy utilization rate to 65%, breaks through the mineralization bottleneck of difficult-to-degrade pollutants, and realizes high-value-added transformation through hydrogen co-production and rare earth recycling.

[0061] (2) The present invention constructs a “carbon nanotube-rare earth doped photocatalyst” treatment process to achieve microwave-plasma synergistic mineralization, improve the overall efficiency by 2.5 times, and achieve high-value utilization of rare earth through targeted recovery (magnetic separation + acid washing purification). Combined with online monitoring and dynamic control of process parameters, it provides a low-carbon and efficient solution for sludge treatment.

[0062] (3) Blockchain-digital twin fusion real-time mapping system status, RAFT-BFT hybrid consensus takes into account high-frequency data processing and strong consistency, dynamic value capture and cross-border collaboration promote sludge treatment from "end treatment" to "resource-finance" closed loop.

[0063] This invention significantly improves sludge treatment efficiency and resource utilization through multi-technology synergy and intelligent control. The synergistic effect of photocatalysis and bioelectrochemistry achieves a microplastic degradation rate >98% and a Cr(VI) removal rate >95%, while microwave-plasma staged mineralization achieves an antibiotic removal rate >99%. Sludge is precisely converted into lithium iron phosphate precursor (specific capacity 160mAh / g), high-purity hydrogen (yield 18L / kg), and carbon-negative building materials (compressive strength 48MPa), increasing economic benefits by 6-8 times. The invention proposes dynamic fractional optimization and multimodal sensing technology based on Hyperledger Fabric, ensuring data immutability and a rare earth targeted recovery rate >90%. The entire process reduces carbon emissions by 55%-65%, energy consumption is ≤120kWh / ton, and hydrogen production provides electricity simultaneously, achieving a closed loop of pollution control and resource recycling. This invention breaks through the traditional single-mode approach, combining high efficiency, intelligence, and sustainability, providing an innovative solution for sludge treatment.

[0064] It will be understood by those skilled in the art that the above descriptions are merely preferred examples of the invention and are not intended to limit the invention. Although the invention has been described in detail with reference to the foregoing examples, those skilled in the art can still modify the technical solutions described in the foregoing examples or make equivalent substitutions for some of the technical features. All modifications and equivalent substitutions made within the spirit and principles of the invention should be included within the scope of protection of the invention.

Claims

1. A multi-stage sludge resource recovery system, characterized in that, The application relates to a photocatalysis-bioelectrochemical pretreatment unit, a microwave-plasma multistage mineralization unit and a blockchain intelligent fractionation module. The photocatalysis-bioelectrochemical pretreatment unit comprises a double-chamber reactor separated by light-transmitting quartz glass, a sludge to be treated is introduced into an anode chamber of the reactor, an ultraviolet-visible light source is arranged in the anode chamber, and a g-C3N4 / TiO2 heterojunction photocatalyst is loaded on the surface of the anode; an acidic electrolyte containing Pd / Fe3O4 nanoparticles is injected into a cathode chamber of the reactor, a three-dimensional graphene foam substrate is used as the cathode, and a Pd / Fe3O4 composite catalyst is loaded on the surface of the three-dimensional graphene foam substrate. The microwave-plasma multistage mineralization unit comprises a quartz reaction cavity, a microwave emitter arranged at the top of the quartz reaction cavity, a plasma emitter arranged on the side wall of the quartz reaction cavity and a permanent magnet roller arranged at the outlet of the quartz reaction cavity; a microwave sensitizer is added into the quartz reaction cavity, organic matters are pyrolyzed in the quartz reaction cavity in stages, intermediate mineralization products are mineralized, and rare earths are targetedly recovered through changes of the power and frequency of the microwave emitter and the plasma emitter; and the permanent magnet roller is used for separating products generated in each stage and inputting the products into the blockchain intelligent fractionation module. The blockchain intelligent fractionation module dynamically optimizes a fractionation path through multi-modal sensing and an intelligent contract, and sends each component in the sludge after mineralization treatment into a corresponding subsystem through the optimized fractionation path for resource conversion. The g-C3N4 / TiO2 heterojunction is prepared through melamine thermal polymerization and atomic layer deposition process; and the Pd / Fe3O4 composite catalyst is synthesized through a chemical reduction method, the magnetic saturation intensity is greater than or equal to 45 emu / g, and the hydrogen evolution overpotential is less than or equal to 98 mV.

2. The sludge multi-stage valorization system according to claim 1, characterized in that, The quartz reaction cavity of the microwave-plasma multistage mineralization unit is lined with a polytetrafluoroethylene corrosion-resistant layer, a pretreated sludge inlet is formed in the upper end of the quartz reaction cavity and used for introducing the pretreated sludge obtained from the photocatalysis-bioelectrochemical pretreatment unit, and a mineralized sludge outlet is formed in the lower end of the quartz reaction cavity and used for outputting the mineralized sludge obtained from the microwave-plasma multistage mineralization unit.

3. The sludge multi-stage resource recovery system of claim 1, wherein, The microwave sensitizer has an Fe3O4@SiO2 core-shell structure, and the adding amount is 1%-2% of the dry weight of the sludge.

4. The sludge multi-stage resource recovery system of claim 1, wherein, The blockchain intelligent fractionation module is based on a Hyperledger Fabric and constructs a private chain architecture, integrates a multi-modal sensing terminal, a pneumatic-magnetoelectric coupling sorting machine and a robot grabbing system, and dynamically optimizes a fractionation path through an intelligent contract.

5. The sludge multi-stage resource recovery system of claim 1, wherein, The integrated multi-modal sensing terminal realizes real-time detection of the content and form of heavy metals, rare earth elements and organic pollutants in the sludge through X-ray fluorescence spectroscopy, laser-induced breakdown spectroscopy and near-infrared-Raman combined technology. The pneumatic-magnetoelectric coupling sorting machine comprises a high-pressure cyclone, a superconducting magnetic separator and a dielectric sorting unit; the high-pressure cyclone is used for separating organic matters and slag according to density differences; the superconducting magnetic separator is used for targetedly adsorbing rare earth-containing magnetic particles; and the dielectric sorting unit is used for separating silicon-aluminum and phosphorus components according to dielectric constant differences. ​ The robot grabbing system is constructed based on a YOLOv7 visual model, used for sending organic matter into a supercritical water gasification hydrogen production subsystem to obtain high-purity hydrogen, sending rare earth magnetic particles into a rare earth recovery subsystem to output high-purity rare earth, and sending silicon aluminum and phosphorus components into a building material synthesis subsystem to synthesize carbon-negative building materials or lithium iron phosphate precursors.

6. The sludge multi-stage resource recovery system of claim 1, wherein, The blockchain intelligent quality separation module synchronously accesses carbon trading and a supply chain, and guarantees that data is tamper-proof and resources are traceable.

7. A multi-stage sludge resource utilization closed-loop management method, realized based on the multi-stage sludge resource utilization system according to any one of claims 1-6, characterized in that, The method comprises the following steps: S1: The sludge slurry to be treated is input into the anode chamber, and an ultraviolet-visible light source irradiates the anode loaded with a photocatalyst to generate electron-hole pairs, wherein the holes are responsible for oxidizing refractory organic matter, and the electrons are transmitted to the cathode chamber through an external circuit; in the cathode chamber, the electrons participate in the reaction of generating hydrogen and reducing heavy metal ions; at the same time, the facultative anaerobes in the anode chamber utilize the intermediate products generated by photocatalysis as a carbon source to further degrade pollutants, and the released electrons are used to supplement the electrons generated by photocatalysis, forming a photo-biological synergistic effect; S2: The pretreated sludge is input into a quartz reaction cavity, and a microwave sensitizer is added; During the reaction process, the pretreated sludge is treated in three stages, including pyrolyzing macromolecular organic matter, mineralizing small-molecule intermediate products, and promoting the crystal phase recombination of rare earth oxides; the rare earth oxides are separated by a permanent magnet roller, and then high-purity rare earth metals are obtained through dilute nitric acid leaching and electrolytic deposition; S3: The sludge components are detected in real time by the blockchain intelligent quality separation module, and the quality separation path is dynamically optimized, so that different components are input into different subsystems, and the sludge is converted into high-purity rare earth, high-purity hydrogen, lithium iron phosphate precursors and carbon-negative building materials.

8. The multi-stage resource recovery closed-loop management method of sludge according to claim 7, characterized in that, In S1, the light irradiation mode of the ultraviolet-visible light source includes a continuous light irradiation mode and an intermittent pulse mode to optimize the light energy utilization efficiency; the continuous light irradiation mode is suitable for highly polluted sludge.

9. The multi-stage resource recovery closed-loop management method of sludge according to claim 7, characterized in that, In S2, the pretreated sludge is treated in three stages, including: Stage one: in the first 0-15 minutes of the operation of the quartz reaction cavity, the microwave power of the microwave emitter is 80%, the polar molecules in the sludge are selectively heated by the microwave, the temperature in the quartz reaction cavity is rapidly increased to 100-120℃, the pyrolysis of organic matter is promoted, and the chemical bonds are disturbed by the non-thermal effect to accelerate the chain scission of perfluorinated compounds; Stage two: in the first 15-30 minutes of the operation of the quartz reaction cavity, the power of the plasma emitter is increased to 70%, the Ar / O2 mixed gas is ionized by the dielectric barrier discharge plasma generator to generate high-energy electrons, hydroxyl radicals and ozone to drive the mineralization of small-molecule intermediate products by hydroxyl radicals; Stage three: in the first 30-40 minutes of the operation of the quartz reaction cavity, the frequency of the microwave emitter is reduced to 1.8 GHz to promote the crystal phase recombination of rare earth oxides.

10. The method of claim 7, wherein the method further comprises: S3 is realized by the following sub-steps: (3.1) The sludge is detected by a multi-modal sensing terminal, the detection data are processed by an edge computing node to generate a feature matrix, and then transmitted to a blockchain decision hub; In the blockchain decision center, the smart contract dynamically optimizes the separation path according to a multi-objective optimization function; the multi-objective optimization function is to maximize the sum of the product of the resource income and the first weight coefficient, the product of the total carbon emissions and the second weight coefficient, and the product of the sustainability and the third weight coefficient; the resource income is the difference between the product of the product unit price and the yield and the processing cost, the total carbon emissions are the product of the carbon emission factor and the processing amount of each link, and the sustainability is calculated by the rare earth recovery rate and the hydrogen self-supply rate; the first weight coefficient, the second weight coefficient, and the third weight coefficient are dynamically adjusted through reinforcement learning; (3.3) Based on the determined separation path, organic matter and slag are separated by high-pressure cyclone according to density difference, rare earth-containing magnetic particles are targeted and adsorbed by a superconducting magnetic separator, and silicon-aluminum and phosphorus components are separated by a dielectric separation unit according to dielectric constant difference; (3.4) The robot grabbing system sends each component into the corresponding subsystem for resource conversion: Organic matter is sent to a supercritical water gasification hydrogen production subsystem, which uses a Ni-Al2O3 catalyst to output high-purity hydrogen under the condition of temperature ≥ 374°C and pressure ≥ 22.1 MPa; Rare earth magnetic particles are sent to a rare earth recovery subsystem, which outputs high-purity rare earth through magnetic separation and acid pickling; Silicon-aluminum and phosphorus components are sent to a building material synthesis subsystem to synthesize negative carbon building materials or lithium iron phosphate precursors; the negative carbon building materials are synthesized by high-pressure mineralization reaction of silicon-aluminum-rich sludge and CO2 waste gas to obtain calcite-type CaCO3, and the lithium iron phosphate precursor is obtained by hydrothermal reaction of Li:Fe:P at a molar ratio of 1:1:1.

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