A deep water layer sewage treatment system and method for river sewage

Abstract

The application provides a deep water layer sewage treatment system and method for river sewage, which comprises a pretreatment interception module, an intelligent precise dosing module, a gradient reaction module, a solid-liquid separation-recovery module and an Internet of Things monitoring and control module; the composition of the medicament used in the intelligent precise dosing module comprises, in parts by weight, 40-85 parts of a conventional flocculant, 2-6 parts of an organic coagulant aid, 12-28 parts of a graphene-chitosan grafted beta-cyclodextrin composite adsorbent, 8-22 parts of a magnetic cerium-bismuth composite nano photocatalyst, 4-12 parts of a heavy metal chelating agent, 18-45 parts of a slow-release carrier, 6-18 parts of an oxidation synergist, 3-9 parts of a pH regulator, 7-15 parts of a biological synergist and 2-6 parts of a bactericide; the modules and components of the medicament in the application synergistically act to efficiently remove suspended particles, organic pollutants, ammonia nitrogen, total phosphorus and heavy metals such as Cr 6+ , Pb 2+ , Cd 2+ , etc. in the deep water layer of river sewage, and improve the precision, automation level and resource recovery rate of sewage treatment.

Description

Technical Field

[0001] This invention relates to the field of river wastewater treatment technology, specifically to a deep-water wastewater treatment system and method for river wastewater. Background Technology

[0002] Deep-water sewage in river channels has poor flowability and complex pollutant composition (such as suspended particles, organic pollutants, ammonia nitrogen, total phosphorus, and Cr). 6+ Pb 2+ Cd 2+ Heavy metals, for example, have long faced problems such as low treatment efficiency and insufficient automation.

[0003] In existing technologies, some solutions rely on simple physical interception or single-agent application for treatment. Examples include using graded screens to intercept floating debris and using pumps to lift sludge to the shallow water layer to reduce anaerobic bacteria levels. However, these methods only achieve preliminary purification and have limited effectiveness in removing recalcitrant organic matter and heavy metal ions from deep water layers. Furthermore, they lack dynamic response capabilities to changes in water quality, making them unsuitable for complex treatment conditions. In addition, traditional treatment systems often rely on manual operation, leading to issues such as experience-based control of reagent dosage and poor coordination between different stages of the treatment process, resulting in both resource waste and the risk of secondary pollution.

[0004] In the application of wastewater treatment agents, existing technologies have improved the mixing effect between agents and wastewater to some extent by optimizing agent formulations (such as conventional flocculants like polyaluminum chloride and polyacrylamide). However, the ability to stage pollutants for treatment is lacking. Existing systems mostly use single reaction units and cannot achieve tiered removal based on the characteristics of different pollutants (such as particle size and chemical properties). In particular, there is a lack of technology for the recovery and reuse of magnetic functional components, resulting in resource waste and high treatment costs. Summary of the Invention

[0005] To address the problems existing in the prior art, the present invention provides a deep-water wastewater treatment system and method for river wastewater.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] This application discloses a deep-water wastewater treatment system for river sewage, including a pretreatment interception module: a graded bar screen (pore size 5-20mm) and an S-shaped sedimentation channel are set up to intercept large floating objects and achieve preliminary sedimentation of large-diameter suspended solids by slowing down the water flow. The large floating object interception and removal rate is ≥60%, reducing the load on subsequent treatment.

[0008] Intelligent precision dosing module: Equipped with a high-pressure injection device (pressure 0.6-1.5MPa) and a variable frequency metering pump (flow rate 0.2-1.2L / min), combined with online pH / ORP / dissolved oxygen sensors (detection frequency 3-8min / time), it dynamically adjusts the dosage and depth of the reagent (1-2m) based on the LSTM water quality prediction algorithm, with a reagent dosing accuracy error ≤5%;

[0009] The gradient reaction module consists of three chambers connected in series. The first chamber (flocculation zone) is stirred at a speed of 150-250 r / min for a reaction time of 20-40 min. The second chamber (adsorption-catalysis zone) has a fixed bed of carriers with a residence time of 40-70 min. The third chamber (slow-release degradation zone) is filled with porous carriers and continues to act for 6-10 h to achieve the stepwise removal of pollutants.

[0010] Solid-liquid separation and recovery module: Utilizing a combined process of "deep-water sedimentation-ultrafiltration-magnetic recovery," the sedimentation zone has a hydraulic retention time of 70-100 min, an ultrafiltration membrane pore size of 30-80 nm, and an operating pressure of 0.15-0.35 MPa. It is equipped with an electromagnetic separation device (magnetic field strength 0.3-0.8 T) to achieve the recovery and reuse of magnetic functional components, with a recovery rate ≥85%.

[0011] IoT monitoring and control module: integrates chemical oxygen demand, ammonia nitrogen, total phosphorus, and heavy metals (Cr). 6+ Pb 2+ Cd 2+ The system includes a turbidity sensor, and the data is wirelessly transmitted to a cloud platform to adjust the stirring speed, reagent dosage, and ultrafiltration membrane backwashing frequency in real time, thereby achieving fully automated operation of the entire process.

[0012] By weight, the raw materials of the reagents used in the intelligent precision dosing module include: 40-85 parts of conventional flocculant, 2-6 parts of organic coagulant aid, 12-28 parts of graphene-chitosan grafted β-cyclodextrin composite adsorbent, 8-22 parts of magnetically supported cerium-bismuth composite nano-photocatalyst, 4-12 parts of heavy metal chelating agent, 18-45 parts of slow-release carrier, 6-18 parts of oxidation synergist, 3-9 parts of pH adjuster, 7-15 parts of biosynergist, and 2-6 parts of bactericide.

[0013] By implementing the above technical solutions, the pretreatment interception module uses graded grids and S-shaped sedimentation channels to intercept large floating objects and achieve initial settling of large-diameter suspended solids, reducing the burden on subsequent treatment. The intelligent precision dosing module utilizes high-pressure jetting devices, variable frequency metering pumps, online sensors, and LSTM water quality prediction algorithms to achieve precise dynamic control of reagent dosage and depth. The gradient reaction module achieves tiered removal of pollutants through different process parameters and structural designs of three-stage series chambers. The solid-liquid separation-recovery module employs a combined process of "deep-water sedimentation-ultrafiltration-magnetic recovery" and an electromagnetic separation device to achieve effective solid-liquid separation and the recovery and reuse of magnetic functional components. IoT monitoring... The monitoring and control module integrates multiple water quality sensors to achieve fully automated control of the entire process. Conventional flocculants and organic coagulants in the reagent work synergistically to achieve flocculation; a graphene-chitosan-grafted β-cyclodextrin composite adsorbent adsorbs pollutants; a magnetically supported cerium-bismuth composite nano-photocatalyst catalyzes the degradation of pollutants; a heavy metal chelating agent specifically treats heavy metals; a slow-release carrier prolongs the reagent's action time; an oxidation synergist optimizes the reaction environment; a pH adjuster maintains suitable acid-base conditions; a biosynergist assists in pollutant removal; and a bactericide kills bacteria. All modules and reagent components work synergistically to efficiently remove suspended particles, organic pollutants, ammonia nitrogen, total phosphorus, and Cr from deep-water sewage in rivers. 6+ Pb 2 + Cd 2+ Removing heavy metals can improve the accuracy, automation level, and resource recycling rate of wastewater treatment.

[0014] Preferably, the conventional flocculant is composed of polyaluminum chloride and polyferric sulfate in a mass ratio of 1.5:1-2:1, the organic coagulant is cationic polyacrylamide or polyethylene oxide, the heavy metal chelating agent is sodium dithiocarbamate or potassium dithiocarbamate, the slow-release carrier is porous diatomaceous earth or expanded perlite, the oxidation synergist is calcium peroxide or sodium persulfate, the pH adjuster is a sodium bicarbonate-potassium dihydrogen phosphate composite system composed of sodium bicarbonate and potassium dihydrogen phosphate in a mass ratio of 1:1-3:1, the biosynergist is humic acid or fulvic acid, and the bactericide is polyhexamethylene guanidine hydrochloride or polyquaternium-6.

[0015] By implementing the above technical solutions, polyaluminum chloride and polyferric sulfate hydrolyze to generate Al(OH)3 and Fe(OH)3 polynuclear hydroxide flocs. These flocs disrupt the colloidal stability of pollutants through charge neutralization, trapping suspended particles and forming primary flocs. Organic coagulant aids, such as cationic polyacrylamide or polyethylene oxide, connect the primary flocs through molecular chain bridging, increasing floc size and density, and improving sedimentation and separation efficiency. Heavy metal chelating agents, such as sodium dithiocarbamate or potassium dithiocarbamate, form stable chelates with heavy metal ions, enhancing heavy metal removal. Slow-release carriers, such as porous diatomaceous earth or expanded perlite, adsorb and lock in the active ingredients of the agents due to their high porosity, delaying their diffusion and loss in deep water and extending the duration of agent action. Oxidation synergists, such as calcium peroxide or sodium persulfate, release active oxygen, increasing dissolved oxygen content in deep water layers, enhancing catalytic oxidation reactions, and inhibiting the growth of anaerobic bacteria. A pH adjuster, a composite system of sodium bicarbonate and potassium dihydrogen phosphate, precisely adjusts the pH of the wastewater, providing suitable acid-base conditions for various reactions. Biosynergists, such as humic acid or fulvic acid, provide carbon and electron donors, promoting microbial metabolism and aiding in the adsorption of heavy metals and organic pollutants. Bactericides, such as polyhexamethylene guanidine hydrochloride or polyquaternium-6, disrupt bacterial cell membrane permeability, killing anaerobic pathogens in deep-water layers. The synergistic effect of these components efficiently removes various pollutants from deep-water wastewater in rivers, improving wastewater treatment outcomes.

[0016] Preferably, the raw materials of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent, by weight, include: 6-10 parts graphene powder, 90-100 parts chitosan, 30-50 parts β-cyclodextrin, 3-8 parts glutaraldehyde, 150-200 parts hydrochloric acid solution, 100-150 parts sodium hydroxide solution, and 0.2-0.4 parts sodium dodecyl sulfate.

[0017] By employing the above technical solutions, graphene powder possesses an ultra-high specific surface area, providing abundant adsorption sites and enhancing its adsorption capacity for pollutants; chitosan contains amino groups, enabling it to form complexes with heavy metal ions, thus improving the removal efficiency of heavy metals; β-cyclodextrin has hydrophobic cavities, which can capture recalcitrant organic pollutants; glutaraldehyde acts as a crosslinking agent, promoting the grafting reaction between chitosan and β-cyclodextrin and stabilizing the structure of the composite adsorbent; hydrochloric acid solution is used to dissolve chitosan, and sodium hydroxide solution is used to adjust the pH, ensuring suitable reaction conditions; sodium dodecyl sulfate acts as a surfactant, promoting the dispersion of graphene, preventing agglomeration, and ensuring its uniform distribution. The combined action of these components endows the composite adsorbent with the ability to complex heavy metal ions and encapsulate recalcitrant organic pollutants, thereby enhancing its adsorption performance.

[0018] Preferably, the degree of deacetylation of chitosan is 85-90%, the molar concentration of hydrochloric acid solution is 0.5-1.0 mol / L, and the molar concentration of sodium hydroxide solution is 0.5-1.0 mol / L.

[0019] By setting the above technical solutions, the degree of deacetylation range can ensure that the chitosan molecules contain sufficient amino sites, providing the necessary conditions for subsequent complexation with heavy metal ions, thereby ensuring the complexation and removal capacity of the composite adsorbent for heavy metals; the molar concentration of the hydrochloric acid solution is 0.5-1.0 mol / L, which ensures that the chitosan is fully dissolved to form a homogeneous solution, avoiding insufficient dissolution of chitosan due to too low a concentration, which would affect the subsequent grafting reaction, or excessive concentration, which would damage the chitosan molecular structure, thus laying a good foundation for the grafting reaction of chitosan and β-cyclodextrin; the molar concentration of the sodium hydroxide solution is 0.5-1.0 mol / L, which can precisely adjust the pH value of the reaction system to a suitable range, meeting the neutralization requirements of the system after the grafting reaction, and avoiding excessive pH adjustment due to improper concentration, thereby ensuring the structural stability and adsorption performance of the composite adsorbent.

[0020] Preferably, the preparation method of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent includes the following steps:

[0021] 1) Disperse graphene powder in deionized water to form a solution with a concentration of 0.8-2.0 mg / mL, add sodium dodecyl sulfate, and ultrasonically disperse at 500-700 W power for 40-60 min to obtain a graphene dispersion.

[0022] 2) Add chitosan to hydrochloric acid solution and stir at 200-300 r / min at 35-45℃ for 30-50 min. Adjust the pH to 5.0-6.0, add β-cyclodextrin, and continue stirring at the same speed for 60-90 min.

[0023] 3) Slowly add glutaraldehyde to the mixture obtained in 2), stir at 300-400 r / min at 40-50℃ for 2-3 h, then add graphene dispersion, continue stirring at the same speed for 30-40 min, and then ultrasonically disperse for 30-45 min under the conditions of power 400-600W and ultrasonic frequency 20-40kHz.

[0024] 4) Adjust the pH of the solution obtained in 3) to 7.0-8.0 with sodium hydroxide solution, filter under vacuum, wash with deionized water until neutral after precipitation, dry at 105-120℃ for 5-8 hours, grind to 180-250 mesh to obtain graphene-chitosan grafted β-cyclodextrin composite adsorbent.

[0025] By setting up the above technical solution, adding sodium dodecyl sulfate to the graphene powder dispersion system and performing ultrasonic dispersion can effectively prevent graphene agglomeration and ensure its uniform dispersion in deionized water, laying the foundation for subsequent full compounding with other components. Chitosan is dissolved in hydrochloric acid solution by stirring at a specific temperature and speed, and the pH is adjusted to a suitable range. Then, β-cyclodextrin is added and stirring is continued to ensure that chitosan is fully dissolved and provides a suitable environment for the reaction between chitosan and β-cyclodextrin, promoting the initial combination of the two. After adding glutaraldehyde and controlling the temperature and speed of the reaction, the cross-linking effect of glutaraldehyde can promote the grafting reaction between chitosan and β-cyclodextrin. The subsequent addition of graphene dispersion and ultrasonic dispersion can further promote the uniform fusion of each component and enhance the composite effect. Finally, by adjusting the pH, vacuum filtration, washing, drying and grinding, the reaction system can be neutralized and impurities removed to obtain a composite adsorbent with high purity and uniform particle size, ensuring its structural stability, and thus enabling the graphene-chitosan-grafted β-cyclodextrin composite adsorbent to have good adsorption performance.

[0026] Preferably, the raw materials of the magnetically supported cerium-bismuth composite nanophotocatalyst, by weight, include: 90-100 parts of bismuth nitrate, 30-80 parts of cerium nitrate, 250-450 parts of citric acid, 50-100 parts of ethylene glycol, 100-140 parts of ferric chloride, 40-60 parts of ferrous chloride, and 100-200 parts of ammonia.

[0027] By setting up the above technical solution, bismuth nitrate and cerium nitrate, as precursors of cerium-bismuth composite oxide, can provide the bismuth and cerium ions required for photocatalytic activity, endowing the catalyst with the core performance of oxidizing and degrading pollutants under weak light. Ferric chloride and ferrous chloride are key raw materials for preparing the Fe3O4 magnetic core, which can form magnetic components through reaction, enabling the catalyst to have magnetic separation and recovery capabilities. Citric acid can form stable complexes with various metal ions, promoting uniform dispersion of components and laying the foundation for the subsequent sol-gel process. Ethylene glycol can regulate the reaction system environment, assist in the formation of a uniform sol, and improve the structural stability of the catalyst. Ammonia can adjust the pH value of the reaction system, promoting the precipitation of Fe3O4 magnetic particles and related precursors of cerium-bismuth composite oxide. The synergistic effect of each raw material enables the magnetically supported cerium-bismuth composite nanophotocatalyst to simultaneously possess photocatalytic activity and magnetic recovery function.

[0028] Preferably, the preparation method of the magnetically supported cerium-bismuth composite nanocatalyst includes the following steps:

[0029] a. Dissolve ferric chloride and ferrous chloride in deionized water, heat to 75-85℃ under nitrogen protection, stir at 250-350 r / min for 30 min, add ammonia dropwise to adjust the pH to 10-11, continue stirring for 2 h, wash the precipitate three times alternately with deionized water and anhydrous ethanol, and then vacuum dry at 60-70℃ for 12 h to obtain Fe3O4 magnetic particles;

[0030] b. Disperse Fe3O4 magnetic particles in deionized water to prepare a Fe3O4 dispersion with a concentration of 0.5-1.0 mg / mL; separately, dissolve bismuth nitrate in deionized water at a solid-liquid ratio of 1 g:50 mL to 1 g:100 mL to prepare a bismuth nitrate solution; take cerium nitrate and dissolve it in deionized water at a solid-liquid ratio of 1 g:20 mL to 1 g:30 mL to prepare a cerium nitrate solution.

[0031] c. Slowly add cerium nitrate solution dropwise to bismuth nitrate solution, stir at 350-550 r / min for 25-40 min, adjust the pH value to 3.5-5.5 with citric acid, and stir at the same speed at 65-85℃ for 150-210 min to form a homogeneous sol. Then, add Fe3O4 dispersion dropwise to the sol at a mass ratio of Fe3O4 magnetic particles to bismuth nitrate of 1:1.2-1.8, and continue stirring at the same speed for 30-40 min.

[0032] d. The mixture obtained in c is evaporated at 85-95℃ for 5-8h to form a gel, which is then vacuum dried at 105-120℃ for 10-16h. The dried gel is then placed in a muffle furnace and heated to 580-620℃ at a rate of 6-12℃ / min for 3-5h. After that, it is naturally cooled to room temperature and then pulverized to 40-80nm by airflow to obtain a magnetically supported cerium-bismuth composite nanocatalyst.

[0033] By employing the aforementioned technical solution, the Fe3O4 magnetic core prepared via co-precipitation imparts superparamagnetism to the material, facilitating rapid separation and recovery under an external magnetic field. This solves the problem of difficult recovery of traditional photocatalysts, achieving a catalyst recovery efficiency of over 90%. Furthermore, the mixing of cerium nitrate and bismuth nitrate solutions and the sol-gel process promote the uniform loading of cerium-bismuth composite oxides onto the surface of the magnetic core, forming an active layer with a band gap of 2.2-2.8 eV. This effectively responds to visible light, improves the separation efficiency of photogenerated carriers, and generates active free radicals (such as -OH and O2) under weak light conditions. - This process achieves highly efficient oxidative degradation of organic pollutants and ammonia nitrogen. The calcination activation step further optimizes the crystal structure of the composite oxide, enhancing its chemical stability and catalytic activity. The resulting magnetically supported cerium-bismuth composite nanocatalyst combines convenient magnetic recovery with highly efficient photocatalytic performance. In wastewater treatment, it can significantly improve the removal rate of recalcitrant organic matter, while also enabling recycling through magnetic separation, thus reducing operating costs.

[0034] Preferably, the mass fraction of ammonia is 20-25 wt%.

[0035] By setting up the above technical solution, 20-25wt% ammonia water can precisely adjust the pH of the reaction system to 10-11, providing a suitable alkaline environment for the co-precipitation reaction of ferric chloride and ferrous chloride. This avoids both insufficient pH adjustment efficiency and incomplete reaction due to excessively low concentration, and the agglomeration of Fe3O4 magnetic particles caused by excessively high concentration, ensuring that the generated Fe3O4 magnetic particles have uniform particle size and good crystallinity. This lays the foundation for the uniform loading of cerium-bismuth composite oxides in the future, thereby ensuring the magnetic recovery performance and catalytic activity of the magnetically supported cerium-bismuth composite nanocatalyst.

[0036] Preferably, the preparation method of the reagent used in the intelligent precision dosing module includes the following steps:

[0037] (1) Add conventional flocculant and pH adjuster to a pressure-resistant mixing vessel in proportion, and stir at 180-280 r / min for 20-30 min at 22-32℃ to form a uniform mixture;

[0038] (2) Add the slow-release carrier and biosynergist to the mixture obtained in (1), heat to 45-55℃, stir at 350-450r / min for 40-60min, then add graphene-chitosan grafted β-cyclodextrin composite adsorbent, magnetically supported cerium bismuth composite nanophotocatalyst and heavy metal chelating agent in sequence, stir at 28-38℃ at 300-400r / min for 70-100min; when stirring for 30-40min, start ultrasonic dispersion (power 400-600W), continue ultrasonication for 30-45min, and keep stirring at 300-400r / min during this period;

[0039] (3) Add oxidizing synergist and bactericide to the mixture obtained in (2), stir at 100-150 r / min for 25-35 min, and finally add organic coagulant, stir at 60-120 r / min for 18-25 min to obtain the desired agent.

[0040] By setting up the above technical solution, a stable basic system is first formed between conventional flocculants and pH adjusters. Then, heating and stirring are used to promote the loading of effective components onto the slow-release carrier. Ultrasonic dispersion effectively avoids the aggregation of functional components such as graphene-chitosan-grafted β-cyclodextrin composite adsorbents and magnetically supported cerium-bismuth composite nano-photocatalysts, ensuring full contact with heavy metal chelating agents and the construction of a synergistic structure. Finally, gentle stirring integrates oxidizing synergists, bactericides, and organic coagulants to form an integrated agent with adsorption, catalysis, flocculation, slow release, and bactericidal functions. The synergistic effect of each component is fully utilized, which can significantly improve the removal efficiency of pollutants in wastewater, the duration of agent action, and the economic efficiency of use.

[0041] This application also discloses a wastewater treatment method for a deep-water wastewater treatment system for river wastewater, comprising the following steps:

[0042] S1. For waters with a depth of 1-3m, the water is first pretreated with a graded screen (5-20mm) and an S-shaped sedimentation channel (flow velocity 0.1-0.3m / s) to remove ≥60% of large floating objects;

[0043] S2. Based on the LSTM algorithm, wastewater treatment agents are precisely added using a high-pressure jetting device (0.6-1.5MPa) and a variable frequency metering pump, with a dosing error of ≤5%.

[0044] S3. Subsequently, the wastewater enters a three-stage chamber gradient reaction (flocculation 20-40 min, adsorption-catalysis 40-70 min, slow-release degradation 6-10 h).

[0045] S4. Solid-liquid separation is achieved through deep-water sedimentation-ultrafiltration (30-80nm)-electromagnetic separation (0.3-0.8T), with catalyst recovery rate ≥85%;

[0046] S5: Real-time water quality monitoring via IoT sensors, dynamic adjustment of process parameters, fully automated operation, and efficient removal of pollutants.

[0047] By implementing the above technical solutions, the graded bar screen and S-shaped sedimentation channel pretreatment remove a large amount of large floating debris, clearing obstacles for subsequent reactions; the LSTM algorithm combined with a high-pressure jet device and a variable frequency metering pump enables precise dosing of wastewater treatment agents, improving agent utilization; the three-stage chamber gradient reaction enhances flocculation, adsorption-catalysis, and slow-release degradation in stages, ensuring the full removal of different types of pollutants; deep-water sedimentation-ultrafiltration-electromagnetic separation synergistically achieves efficient solid-liquid separation and ensures a high recovery rate of the magnetically loaded cerium-bismuth composite nanocatalyst; real-time monitoring and dynamic process control by IoT sensors enable fully automated operation, stably and efficiently removing various pollutants from wastewater.

[0048] The beneficial effects of this invention are as follows:

[0049] The pretreatment interception module uses graded grids and S-shaped sedimentation channels to intercept large floating objects and initially settle large-diameter suspended solids, reducing the burden on subsequent treatment. The intelligent precision dosing module utilizes high-pressure jetting devices, variable-frequency metering pumps, online sensors, and LSTM water quality prediction algorithms to achieve precise dynamic control of reagent dosage and depth. The gradient reaction module achieves tiered removal of pollutants through different process parameters and structural designs in a three-stage series chamber. The solid-liquid separation-recovery module employs a combined process of "deep-water sedimentation-ultrafiltration-magnetic recovery" and an electromagnetic separation device to achieve effective solid-liquid separation and the recovery and reuse of magnetic functional components. The IoT monitoring and control module... This system integrates multiple water quality sensors to achieve fully automated control throughout the entire process. Conventional flocculants and organic coagulants work synergistically in the reagent to achieve flocculation; a graphene-chitosan-grafted β-cyclodextrin composite adsorbent adsorbs pollutants; a magnetically supported cerium-bismuth composite nano-photocatalyst catalyzes the degradation of pollutants; a heavy metal chelating agent specifically treats heavy metals; a slow-release carrier prolongs the reagent's action time; an oxidation synergist optimizes the reaction environment; a pH adjuster maintains suitable acid-base conditions; a biosynergist assists in pollutant removal; and a bactericide kills bacteria. All modules and reagent components work synergistically to efficiently remove suspended particles, organic pollutants, ammonia nitrogen, total phosphorus, and Cr from deep-water wastewater in rivers. 6+ Pb 2+ Cd 2+ Removing heavy metals can improve the accuracy, automation level, and resource recycling rate of wastewater treatment. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] Example 1:

[0052] This embodiment discloses a deep-water wastewater treatment system for river sewage, including a pretreatment interception module: a graded grid (5mm aperture) and an S-shaped sedimentation channel are set up to intercept large floating objects and achieve preliminary sedimentation of large-diameter suspended solids by slowing down the water flow. The large floating object interception and removal rate is ≥60%, reducing the load on subsequent treatment.

[0053] Intelligent precision dosing module: Equipped with a high-pressure injection device (pressure 0.6MPa) and a variable frequency metering pump (flow rate 0.2L / min), combined with online pH / ORP / dissolved oxygen sensors (detection frequency 3min / time), it dynamically adjusts the dosage and depth of the reagent based on the LSTM water quality prediction algorithm, with a reagent dosing accuracy error of ≤5%;

[0054] The gradient reaction module consists of three chambers connected in series. The first chamber (flocculation zone) is stirred at a speed of 150 r / min for 20 min. The second chamber (adsorption-catalysis zone) has a fixed bed of carrier with a residence time of 40 min. The third chamber (slow-release degradation zone) is filled with a porous carrier and acts continuously for 6 h to achieve the stepwise removal of pollutants.

[0055] Solid-liquid separation and recovery module: Utilizing a combined process of "deep-water sedimentation-ultrafiltration-magnetic recovery," the sedimentation zone has a hydraulic retention time of 70 minutes, an ultrafiltration membrane pore size of 30 nm, and an operating pressure of 0.15 MPa. It is equipped with an electromagnetic separation device (magnetic field strength 0.3 T) to achieve the recovery and reuse of magnetic functional components, with a recovery rate ≥85%.

[0056] IoT monitoring and control module: integrates chemical oxygen demand, ammonia nitrogen, total phosphorus, and heavy metals (Cr). 6+ Pb 2+ Cd 2+ The system includes a turbidity sensor, and the data is wirelessly transmitted to a cloud platform to adjust the stirring speed, reagent dosage, and ultrafiltration membrane backwashing frequency in real time, thereby achieving fully automated operation of the entire process.

[0057] By weight, the raw materials of the reagents used in the intelligent precision dosing module include: 40 parts of conventional flocculant, 2 parts of organic coagulant aid, 12 parts of graphene-chitosan grafted β-cyclodextrin composite adsorbent, 8 parts of magnetically supported cerium-bismuth composite nanophotocatalyst, 4 parts of heavy metal chelating agent, 18 parts of slow-release carrier, 6 parts of oxidation synergist, 3 parts of pH adjuster, 7 parts of biosynergist, and 2 parts of bactericide.

[0058] The conventional flocculant is composed of polyaluminum chloride and polyferric sulfate in a mass ratio of 1.5:1. The organic coagulant aid is cationic polyacrylamide or polyethylene oxide. The heavy metal chelating agent is sodium dithiocarbamate or potassium dithiocarbamate. The slow-release carrier is porous diatomaceous earth or expanded perlite. The oxidation synergist is calcium peroxide or sodium persulfate. The pH adjuster is a sodium bicarbonate-potassium dihydrogen phosphate composite system composed of sodium bicarbonate and potassium dihydrogen phosphate in a mass ratio of 1:1. The biosynergist is humic acid or fulvic acid. The bactericide is polyhexamethylene guanidine hydrochloride or polyquaternium-6.

[0059] The raw materials of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent, by weight, include: 6 parts graphene powder, 90 parts chitosan with a degree of deacetylation of 85%, 30 parts β-cyclodextrin, 3 parts glutaraldehyde, 150 parts hydrochloric acid solution with a molar concentration of 0.5 mol / L, 100 parts sodium hydroxide solution with a molar concentration of 0.5 mol / L, and 0.2 parts sodium dodecyl sulfate.

[0060] The preparation method of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent includes the following steps:

[0061] 1) Graphene powder was dispersed in deionized water to form a solution with a concentration of 0.8 mg / mL. Sodium dodecyl sulfate was added and ultrasonically dispersed at 500 W for 40 min to obtain a graphene dispersion.

[0062] 2) Add chitosan to hydrochloric acid solution, stir at 200 r / min for 30 min at 35℃, adjust the pH to 5.0, add β-cyclodextrin, and continue stirring at the same speed for 60 min;

[0063] 3) Glutaraldehyde was slowly added dropwise to the mixture obtained in 2), and the mixture was stirred at 300 r / min at 40℃ for 2 h. Then graphene dispersion was added, and the mixture was stirred at the same speed for 30 min. Finally, the mixture was ultrasonically dispersed for 30 min at a power of 400 W and an ultrasonic frequency of 20 kHz.

[0064] 4) Adjust the pH of the solution obtained in 3) to 7.0 with sodium hydroxide solution, filter under vacuum, wash with deionized water until neutral after precipitation, dry at 105℃ for 5 hours, grind to 180 mesh to obtain graphene-chitosan grafted β-cyclodextrin composite adsorbent.

[0065] The raw materials of the magnetically supported cerium-bismuth composite nanophotocatalyst, by weight, include: 90 parts bismuth nitrate, 30 parts cerium nitrate, 250 parts citric acid, 50 parts ethylene glycol, 100 parts ferric chloride, 40 parts ferrous chloride, and 100 parts ammonia water with a mass fraction of 20 wt%.

[0066] The preparation method of magnetically supported cerium-bismuth composite nanocatalysts includes the following steps:

[0067] a. Dissolve ferric chloride and ferrous chloride in deionized water, heat to 75°C under nitrogen protection, stir at 250 r / min for 30 min, add ammonia dropwise to adjust the pH to 10, continue stirring for 2 h, wash the precipitate three times alternately with deionized water and anhydrous ethanol, and then vacuum dry at 60°C for 12 h to obtain Fe3O4 magnetic particles.

[0068] b. Disperse Fe3O4 magnetic particles in deionized water to prepare a Fe3O4 dispersion with a concentration of 0.5 mg / mL; separately, dissolve bismuth nitrate in deionized water at a solid-liquid ratio of 1 g: 50 mL to prepare a bismuth nitrate solution; take cerium nitrate and dissolve it in deionized water at a solid-liquid ratio of 1 g: 20 mL to prepare a cerium nitrate solution.

[0069] c. Slowly add cerium nitrate solution dropwise to bismuth nitrate solution, stir at 350 r / min for 25 min, adjust the pH value to 3.5 with citric acid, stir at the same speed at 65℃ for 150 min to form a uniform sol, then add Fe3O4 dispersion dropwise to the sol at a mass ratio of Fe3O4 magnetic particles to bismuth nitrate of 1:1.2, and continue stirring at the same speed for 30 min.

[0070] d. The mixture obtained in c was evaporated at 85℃ for 5 hours to form a gel, which was then vacuum dried at 105℃ for 10 hours. The dried gel was then placed in a muffle furnace and heated to 580℃ at a rate of 6℃ / min for 3 hours. After that, it was naturally cooled to room temperature and then pulverized to 40nm by airflow to obtain a magnetically supported cerium-bismuth composite nanocatalyst.

[0071] The preparation method of the reagents used in the intelligent precision dosing module includes the following steps:

[0072] (1) Add conventional flocculant and pH adjuster to a pressure-resistant mixing vessel in proportion, and stir at 180 r / min for 20 min at 22℃ to form a uniform mixture;

[0073] (2) Add the slow-release carrier and bio-synergist to the mixture obtained in (1), heat to 45°C, stir at 350 r / min for 40 min, then add graphene-chitosan grafted β-cyclodextrin composite adsorbent, magnetically supported cerium bismuth composite nanophotocatalyst and heavy metal chelating agent in sequence, stir at 300 r / min at 28°C for 70 min; start ultrasonic dispersion (power 400W) when stirring for 30 min, continue ultrasonication for 30 min, and keep stirring at 300 r / min during the process;

[0074] (3) Add oxidizing synergist and bactericide to the mixture obtained in (2), stir at 100 r / min for 25 min, and finally add organic coagulant, stir at 60 r / min for 18 min to obtain the required agent.

[0075] This embodiment also discloses a wastewater treatment method for a deep-water wastewater treatment system for river wastewater, comprising the following steps:

[0076] S1. For waters with a depth of 1m, the water is first pretreated with a graded screen (5mm) and an S-shaped sedimentation channel (flow velocity 0.1m / s) to remove ≥60% of large floating objects.

[0077] S2. Based on the LSTM algorithm, wastewater treatment agents are precisely added using a high-pressure jetting device (0.6MPa) and a variable frequency metering pump, with a dosing error of ≤5%.

[0078] S3. Subsequently, the wastewater enters a three-stage chamber gradient reaction (flocculation for 20 min, adsorption-catalysis for 40 min, and slow-release degradation for 6 h).

[0079] S4. Solid-liquid separation is achieved through deep-water sedimentation-ultrafiltration (30nm)-electromagnetic separation (0.3T), with catalyst recovery rate ≥85%;

[0080] S5: Real-time water quality monitoring via IoT sensors, dynamic adjustment of process parameters, fully automated operation, and efficient removal of pollutants.

[0081] Example 2:

[0082] This embodiment discloses a deep-water wastewater treatment system for river sewage, including a pretreatment interception module: a graded grid (20mm aperture) and an S-shaped sedimentation channel are set up to intercept large floating objects and achieve preliminary sedimentation of large-diameter suspended solids by slowing down the water flow. The large floating object interception and removal rate is ≥60%, reducing the load on subsequent treatment.

[0083] Intelligent precision dosing module: Equipped with a high-pressure injection device (pressure 1.5MPa) and a variable frequency metering pump (flow rate 1.2L / min), combined with online pH / ORP / dissolved oxygen sensors (detection frequency 8min / time), it dynamically adjusts the dosage and depth (2m) of the reagent based on the LSTM water quality prediction algorithm, with a reagent dosing accuracy error of ≤5%;

[0084] The gradient reaction module consists of three chambers connected in series. The first chamber (flocculation zone) is stirred at a speed of 250 r / min for 40 min. The second chamber (adsorption-catalysis zone) has a fixed bed of carrier with a residence time of 70 min. The third chamber (slow-release degradation zone) is filled with a porous carrier and continues to act for 10 h to achieve the stepwise removal of pollutants.

[0085] Solid-liquid separation and recovery module: Utilizing a combined process of "deep-water sedimentation-ultrafiltration-magnetic recovery," the sedimentation zone has a hydraulic retention time of 100 min, an ultrafiltration membrane pore size of 80 nm, and an operating pressure of 0.35 MPa. It is equipped with an electromagnetic separation device (magnetic field strength 0.8 T) to achieve the recovery and reuse of magnetic functional components, with a recovery rate ≥85%.

[0086] IoT monitoring and control module: integrates chemical oxygen demand, ammonia nitrogen, total phosphorus, and heavy metals (Cr). 6+ Pb 2+ Cd 2+The system includes a turbidity sensor, and the data is wirelessly transmitted to a cloud platform to adjust the stirring speed, reagent dosage, and ultrafiltration membrane backwashing frequency in real time, thereby achieving fully automated operation of the entire process.

[0087] By weight, the raw materials of the reagents used in the intelligent precision dosing module include: 85 parts of conventional flocculant, 6 parts of organic coagulant aid, 28 parts of graphene-chitosan grafted β-cyclodextrin composite adsorbent, 22 parts of magnetically supported cerium-bismuth composite nanophotocatalyst, 12 parts of heavy metal chelating agent, 45 parts of slow-release carrier, 18 parts of oxidation synergist, 9 parts of pH adjuster, 15 parts of biosynergist, and 6 parts of bactericide.

[0088] The conventional flocculant is composed of polyaluminum chloride and polyferric sulfate in a mass ratio of 2:1. The organic coagulant aid is cationic polyacrylamide or polyethylene oxide. The heavy metal chelating agent is sodium dithiocarbamate or potassium dithiocarbamate. The slow-release carrier is porous diatomaceous earth or expanded perlite. The oxidation synergist is calcium peroxide or sodium persulfate. The pH adjuster is a sodium bicarbonate-potassium dihydrogen phosphate composite system composed of sodium bicarbonate and potassium dihydrogen phosphate in a mass ratio of 3:1. The biosynergist is humic acid or fulvic acid. The bactericide is polyhexamethylene guanidine hydrochloride or polyquaternium-6.

[0089] The raw materials of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent, by weight, include: 10 parts graphene powder, 100 parts chitosan with a degree of deacetylation of 90%, 50 parts β-cyclodextrin, 8 parts glutaraldehyde, 200 parts hydrochloric acid solution with a molar concentration of 1.0 mol / L, 150 parts sodium hydroxide solution with a molar concentration of 1.0 mol / L, and 0.4 parts sodium dodecyl sulfate.

[0090] The preparation method of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent includes the following steps:

[0091] 1) Graphene powder was dispersed in deionized water to form a solution with a concentration of 2.0 mg / mL. Sodium dodecyl sulfate was added and ultrasonically dispersed at 700 W for 60 min to obtain a graphene dispersion.

[0092] 2) Add chitosan to hydrochloric acid solution, stir at 300 r / min for 50 min at 45℃, adjust the pH to 6.0, add β-cyclodextrin, and continue stirring at the same speed for 90 min;

[0093] 3) Glutaraldehyde was slowly added dropwise to the mixture obtained in 2), and the mixture was stirred at 400 r / min at 50 °C for 3 h. Then, graphene dispersion was added, and the mixture was stirred at the same speed for 40 min. Finally, it was ultrasonically dispersed for 45 min at a power of 600 W and an ultrasonic frequency of 40 kHz.

[0094] 4) Adjust the pH of the solution obtained in 3) to 8.0 with sodium hydroxide solution, filter under vacuum, wash with deionized water until neutral after precipitation, dry at 120℃ for 8 hours, grind to 250 mesh to obtain graphene-chitosan grafted β-cyclodextrin composite adsorbent.

[0095] The raw materials of the magnetically supported cerium-bismuth composite nanophotocatalyst, by weight, include: 100 parts bismuth nitrate, 80 parts cerium nitrate, 450 parts citric acid, 100 parts ethylene glycol, 140 parts ferric chloride, 60 parts ferrous chloride, and 200 parts ammonia water with a mass fraction of 25 wt%.

[0096] The preparation method of magnetically supported cerium-bismuth composite nanocatalysts includes the following steps:

[0097] a. Dissolve ferric chloride and ferrous chloride in deionized water, heat to 85°C under nitrogen protection, stir at 350 r / min for 30 min, add ammonia dropwise to adjust the pH to 11, continue stirring for 2 h, wash the precipitate three times alternately with deionized water and anhydrous ethanol, and then vacuum dry at 70°C for 12 h to obtain Fe3O4 magnetic particles.

[0098] b. Disperse Fe3O4 magnetic particles in deionized water to prepare a Fe3O4 dispersion with a concentration of 1.0 mg / mL; separately, dissolve bismuth nitrate in deionized water at a solid-liquid ratio of 1 g: 100 mL to prepare a bismuth nitrate solution; take cerium nitrate and dissolve it in deionized water at a solid-liquid ratio of 1 g: 30 mL to prepare a cerium nitrate solution.

[0099] c. Slowly add cerium nitrate solution dropwise to bismuth nitrate solution, stir at 550 r / min for 40 min, adjust the pH to 5.5 with citric acid, and stir at the same speed at 85℃ for 210 min to form a homogeneous sol. Then, add Fe3O4 dispersion dropwise to the sol at a mass ratio of Fe3O4 magnetic particles to bismuth nitrate of 1:1.8, and continue stirring at the same speed for 40 min.

[0100] d. The mixture obtained in c was evaporated at 95℃ for 8 hours to form a gel, which was then vacuum dried at 120℃ for 16 hours. The dried gel was then placed in a muffle furnace and heated to 620℃ at a rate of 12℃ / min for 5 hours. After that, it was naturally cooled to room temperature and then pulverized to 80nm by airflow to obtain a magnetically supported cerium-bismuth composite nanocatalyst.

[0101] The preparation method of the reagents used in the intelligent precision dosing module includes the following steps:

[0102] (1) Add conventional flocculant and pH adjuster to a pressure-resistant mixing vessel in proportion, and stir at 280 r / min for 30 min at 32℃ to form a uniform mixture;

[0103] (2) Add the slow-release carrier and bio-synergist to the mixture obtained in (1), heat to 55°C, stir at 450 r / min for 60 min, then add graphene-chitosan grafted β-cyclodextrin composite adsorbent, magnetically supported cerium bismuth composite nanophotocatalyst and heavy metal chelating agent in sequence, stir at 38°C at 400 r / min for 100 min; start ultrasonic dispersion (power 600 W) when stirring for 40 min, continue ultrasonication for 45 min, and keep stirring at 400 r / min during the period;

[0104] (3) Add oxidizing synergist and bactericide to the mixture obtained in (2), stir at 150 r / min for 35 min, and finally add organic coagulant, stir at 120 r / min for 25 min to obtain the desired agent.

[0105] This embodiment also discloses a wastewater treatment method for a deep-water wastewater treatment system for river wastewater, comprising the following steps:

[0106] S1. For waters with a depth of 3m, the water is first pretreated with a graded screen (20mm) and an S-shaped sedimentation channel (flow velocity 0.3m / s) to remove ≥60% of large floating objects;

[0107] S2. Based on the LSTM algorithm, wastewater treatment agents are precisely added using a high-pressure jetting device (1.5MPa) and a variable frequency metering pump, with a dosing error of ≤5%.

[0108] S3. Subsequently, the wastewater enters a three-stage chamber gradient reaction (flocculation for 40 min, adsorption-catalysis for 70 min, and slow-release degradation for 10 h).

[0109] S4. Solid-liquid separation is achieved through deep-water sedimentation-ultrafiltration (80nm)-electromagnetic separation (0.8T), with catalyst recovery rate ≥85%;

[0110] S5: Real-time water quality monitoring via IoT sensors, dynamic adjustment of process parameters, fully automated operation, and efficient removal of pollutants.

[0111] Example 3:

[0112] This embodiment discloses a deep-water wastewater treatment system for river sewage, including a pretreatment interception module: a graded grid (12mm aperture) and an S-shaped sedimentation channel are set up to intercept large floating objects and achieve preliminary sedimentation of large-diameter suspended solids by slowing down the water flow. The large floating object interception and removal rate is ≥60%, reducing the load on subsequent treatment.

[0113] Intelligent precision dosing module: Equipped with a high-pressure injection device (pressure 1.0MPa) and a variable frequency metering pump (flow rate 0.7L / min), combined with online pH / ORP / dissolved oxygen sensors (detection frequency 5min / time), it dynamically adjusts the dosage and depth of the reagent (1.5m) based on the LSTM water quality prediction algorithm, with a reagent dosing accuracy error of ≤5%;

[0114] The gradient reaction module consists of three chambers connected in series. The first chamber (flocculation zone) is stirred at a speed of 200 r / min for 30 min. The second chamber (adsorption-catalysis zone) has a fixed bed of carrier with a residence time of 55 min. The third chamber (slow-release degradation zone) is filled with a porous carrier and continues to act for 8 h to achieve the stepwise removal of pollutants.

[0115] Solid-liquid separation and recovery module: Employs a combined process of "deep-water sedimentation-ultrafiltration-magnetic recovery," with a hydraulic retention time of 85 minutes in the sedimentation zone, an ultrafiltration membrane pore size of 55 nm, and an operating pressure of 0.25 MPa; it is equipped with an electromagnetic separation device (magnetic field strength 0.5 T) to achieve the recovery and reuse of magnetic functional components, with a recovery rate ≥85%.

[0116] IoT monitoring and control module: integrates chemical oxygen demand, ammonia nitrogen, total phosphorus, and heavy metals (Cr). 6+ Pb 2+ Cd 2+ The system includes a turbidity sensor, and the data is wirelessly transmitted to a cloud platform to adjust the stirring speed, reagent dosage, and ultrafiltration membrane backwashing frequency in real time, thereby achieving fully automated operation of the entire process.

[0117] By weight, the raw materials of the reagents used in the intelligent precision dosing module include: 60 parts of conventional flocculant, 4 parts of organic coagulant aid, 20 parts of graphene-chitosan grafted β-cyclodextrin composite adsorbent, 15 parts of magnetically supported cerium-bismuth composite nanophotocatalyst, 8 parts of heavy metal chelating agent, 25 parts of slow-release carrier, 12 parts of oxidation synergist, 6 parts of pH adjuster, 11 parts of biosynergist, and 4 parts of bactericide.

[0118] The conventional flocculant is composed of polyaluminum chloride and polyferric sulfate in a mass ratio of 2:1. The organic coagulant aid is cationic polyacrylamide or polyethylene oxide. The heavy metal chelating agent is sodium dithiocarbamate or potassium dithiocarbamate. The slow-release carrier is porous diatomaceous earth or expanded perlite. The oxidation synergist is calcium peroxide or sodium persulfate. The pH adjuster is a sodium bicarbonate-potassium dihydrogen phosphate composite system composed of sodium bicarbonate and potassium dihydrogen phosphate in a mass ratio of 2:1. The biosynergist is humic acid or fulvic acid. The bactericide is polyhexamethylene guanidine hydrochloride or polyquaternium-6.

[0119] The raw materials of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent, by weight, include: 8 parts graphene powder, 95 parts chitosan with a degree of deacetylation of 88%, 40 parts β-cyclodextrin, 5 parts glutaraldehyde, 175 parts hydrochloric acid solution with a molar concentration of 0.7 mol / L, 125 parts sodium hydroxide solution with a molar concentration of 0.7 mol / L, and 0.3 parts sodium dodecyl sulfate.

[0120] The preparation method of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent includes the following steps:

[0121] 1) Graphene powder was dispersed in deionized water to form a solution with a concentration of 1.4 mg / mL. Sodium dodecyl sulfate was added and the solution was ultrasonically dispersed at 600 W for 50 min to obtain a graphene dispersion.

[0122] 2) Add chitosan to hydrochloric acid solution, stir at 250 r / min for 40 min at 40℃, adjust the pH to 5.5, add β-cyclodextrin, and continue stirring at the same speed for 75 min;

[0123] 3) Glutaraldehyde was slowly added dropwise to the mixture obtained in 2), and the mixture was stirred at 350 r / min at 45℃ for 2.5 h. Then graphene dispersion was added, and the mixture was stirred at the same speed for 35 min. Finally, the mixture was ultrasonically dispersed for 35 min at a power of 500 W and an ultrasonic frequency of 30 kHz.

[0124] 4) Adjust the pH of the solution obtained in 3) to 7.5 with sodium hydroxide solution, filter under vacuum, wash with deionized water until neutral after precipitation, dry at 110℃ for 7 hours, grind to 210 mesh to obtain graphene-chitosan grafted β-cyclodextrin composite adsorbent.

[0125] The raw materials of the magnetically supported cerium-bismuth composite nanophotocatalyst, by weight, include: 95 parts bismuth nitrate, 55 parts cerium nitrate, 350 parts citric acid, 75 parts ethylene glycol, 120 parts ferric chloride, 50 parts ferrous chloride, and 150 parts ammonia water with a mass fraction of 22 wt%.

[0126] The preparation method of magnetically supported cerium-bismuth composite nanocatalysts includes the following steps:

[0127] a. Dissolve ferric chloride and ferrous chloride in deionized water, heat to 80°C under nitrogen protection, stir at 300 r / min for 30 min, add ammonia dropwise to adjust the pH to 10.5, continue stirring for 2 h, wash the precipitate three times alternately with deionized water and anhydrous ethanol, and then vacuum dry at 65°C for 12 h to obtain Fe3O4 magnetic particles.

[0128] b. Disperse Fe3O4 magnetic particles in deionized water to prepare a Fe3O4 dispersion with a concentration of 0.7 mg / mL; separately, dissolve bismuth nitrate in deionized water at a solid-liquid ratio of 1 g: 75 mL to prepare a bismuth nitrate solution; take cerium nitrate and dissolve it in deionized water at a solid-liquid ratio of 1 g: 25 mL to prepare a cerium nitrate solution.

[0129] c. Slowly add cerium nitrate solution dropwise to bismuth nitrate solution, stir at 450 r / min for 30 min, adjust the pH to 4.5 with citric acid, and stir at the same speed at 75℃ for 180 min to form a homogeneous sol. Then, add Fe3O4 dispersion dropwise to the sol at a mass ratio of Fe3O4 magnetic particles to bismuth nitrate of 1:1.5, and continue stirring at the same speed for 35 min.

[0130] d. The mixture obtained in c was evaporated at 90℃ for 6 hours to form a gel, which was then vacuum dried at 112℃ for 13 hours. The dried gel was then placed in a muffle furnace and heated to 600℃ at a rate of 9℃ / min for 4 hours. After that, it was naturally cooled to room temperature and then pulverized to 40-80 nm by airflow to obtain a magnetically supported cerium-bismuth composite nanocatalyst.

[0131] The preparation method of the reagents used in the intelligent precision dosing module includes the following steps:

[0132] (1) Add conventional flocculant and pH adjuster to a pressure-resistant mixing vessel in proportion, and stir at 230 r / min for 25 min at 27℃ to form a uniform mixture;

[0133] (2) Add the slow-release carrier and bio-synergist to the mixture obtained in (1), heat to 50°C, stir at 400 r / min for 50 min, then add graphene-chitosan grafted β-cyclodextrin composite adsorbent, magnetically supported cerium bismuth composite nanophotocatalyst and heavy metal chelating agent in sequence, stir at 33°C at 350 r / min for 85 min; start ultrasonic dispersion (power 500W) when stirring for 35 min, continue ultrasonication for 37 min, and keep stirring at 350 r / min during the period;

[0134] (3) Add oxidizing synergist and bactericide to the mixture obtained in (2), stir at 125 r / min for 30 min, and finally add organic coagulant, stir at 90 r / min for 22 min to obtain the desired agent.

[0135] This embodiment also discloses a wastewater treatment method for a deep-water wastewater treatment system for river wastewater, comprising the following steps:

[0136] S1. For waters with a depth of 2m, the water is first pretreated with a graded screen (12mm) and an S-shaped sedimentation channel (flow velocity 0.2m / s) to remove ≥60% of large floating objects;

[0137] S2. Based on the LSTM algorithm, wastewater treatment agents are precisely added using a high-pressure jetting device (1.0MPa) and a variable frequency metering pump, with a dosing error of ≤5%.

[0138] S3. Subsequently, the wastewater enters a three-stage chamber gradient reaction (flocculation for 30 min, adsorption-catalysis for 55 min, and slow-release degradation for 8 h).

[0139] S4. Solid-liquid separation is achieved through deep-water sedimentation-ultrafiltration (55nm)-electromagnetic separation (0.5T), with catalyst recovery rate ≥85%;

[0140] S5: Real-time water quality monitoring via IoT sensors, dynamic adjustment of process parameters, fully automated operation, and efficient removal of pollutants.

[0141] Comparative Example 1:

[0142] A deep-water wastewater treatment system and method for river sewage, which differs from Example 3 only in that: no graphene-chitosan-grafted β-cyclodextrin composite adsorbent is added.

[0143] Comparative Example 2:

[0144] A deep-water wastewater treatment system and method for river sewage, which differs from Example 3 only in that: no magnetically supported cerium-bismuth composite nanocatalyst is added.

[0145] Comparative Example 3:

[0146] A deep-water wastewater treatment system and method for river sewage, which differs from Example 3 only in that no organic coagulant is added.

[0147] Comparative Example 4:

[0148] A deep-water wastewater treatment system and method for river sewage, which differs from Example 3 only in that no heavy metal chelating agent is added.

[0149] Comparative Example 5:

[0150] A deep-water wastewater treatment system and method for river sewage, which differs from Example 3 only in that no slow-release carrier is added.

[0151] Comparative Example 6:

[0152] A deep-water wastewater treatment system and method for river sewage, which differs from Example 3 only in that ordinary montmorillonite is used instead of graphene-chitosan-grafted β-cyclodextrin composite adsorbent.

[0153] Comparative Example 7:

[0154] A deep-water wastewater treatment system and method for river sewage, which differs from Example 3 only in that: nano-titanium dioxide is used instead of magnetically supported cerium-bismuth composite nano-photocatalyst.

[0155] Comparative Example 8:

[0156] A deep-water wastewater treatment system and method for river sewage, which differs from Example 3 only in that the graphene-chitosan-grafted β-cyclodextrin composite adsorbent is not modified with β-cyclodextrin grafting.

[0157] Comparative Example 9:

[0158] A deep-water wastewater treatment system and method for river sewage, which differs from Example 3 only in that the ultrasonic dispersion step is not performed during reagent preparation.

[0159] Wastewater treatment systems from Examples 1-3 and Comparative Examples 1-9 were used to treat wastewater from the same river. Chemical oxygen demand (COD), ammonia nitrogen, total phosphorus, turbidity, reagent slow-release performance, catalyst recovery efficiency, and total bacterial count were measured separately for each system. Specific testing methods are as follows:

[0160] (I) Testing Reference Standards and Methods

[0161] Chemical oxygen demand (COD): According to the rapid digestion spectrophotometric method (HJ / T 399-2007), 2.5 mL of water sample was added to the digestion solution, digested at 165℃ for 10 min, and the absorbance was measured at a wavelength of 610 nm. The concentration was calculated according to the standard curve.

[0162] Ammonia nitrogen: According to Nessler's reagent spectrophotometric method (HJ 535-2009), take 50 mL of water sample, adjust the pH to 10.5, add Nessler's reagent, let stand for 10 min, measure the absorbance at a wavelength of 420 nm, and calculate the concentration according to the standard curve.

[0163] Total phosphorus: According to the "Ammonium molybdate spectrophotometric method" (GB 11893-1989), after the water sample is digested with sulfuric acid-potassium persulfate, ammonium molybdate colorimetric reagent is added, and the absorbance is measured at a wavelength of 700 nm. The concentration is calculated according to the standard curve.

[0164] Turbidity: The turbidity value of the water sample was directly measured using a turbidity meter in accordance with the "Determination of Turbidity" (GB / T 5750.4-2006).

[0165] Heavy metals (Pb) 2+ Cd 2+ According to the "Atomic Absorption Spectrophotometry" (GB 7475-1987), the concentration of water samples was determined by atomic absorption spectrometry after acidification and digestion with nitric acid. Cr 6+ According to the "Determination of Hexavalent Chromium in Water - Diphenylcarbazide Spectrophotometric Method" (GB 7467-1987).

[0166] Drug sustained-release performance: Continuous sampling and testing of the active ingredient (Al) within 6 hours. 3+ Fe 3+ The effective release time is defined as follows: effective release time (h) = duration during which the effective component dissolves at a concentration ≥ 50% of the initial concentration.

[0167] Catalyst recovery efficiency: The catalyst is recovered using an electromagnetic separation device. The calculation formula is: Catalyst recovery efficiency (%) = (dry mass of recovered catalyst / dry mass of added catalyst) × 100%.

[0168] Total bacterial count: Based on the "Plate Counting Agar Medium" (GB / T 4789.2-2016), the decanting plate method was used for culture and counting, and the removal rate was calculated.

[0169] (II) Testing Procedures

[0170] Water sample preparation: Wastewater was collected from the deep water layer of the river (3m depth), and the initial water quality indicators were adjusted as follows: COD = 380 mg / L, ammonia nitrogen = 50 mg / L, total phosphorus = 9 mg / L, turbidity = 130 NTU, Cr = 100 mg / L. 6+ =1.5mg / L, Pb 2+ =1.0 mg / L, Cd 2+ =0.3mg / L, total bacterial count =1.2×10 6 CFU / mL.

[0171] System setup: Assemble the experimental device according to the system architecture of this plan to simulate a deep-water environment (pressure 0.15MPa, light intensity 400-900 lux, temperature 15-25℃).

[0172] Dosage of reagents: Add the reagents of each example and comparative example at a liquid-to-solid ratio of 1:800 (reagent: sewage, weight ratio), start the system and run it according to the process parameters (flocculation 30 min, adsorption-catalysis 60 min, slow release degradation 8 h).

[0173] Index detection: Samples were taken after the reaction was completed, and each index was measured according to the above method. Each group of experiments was conducted in parallel 3 times, and the average value was taken as the test result. The relative standard deviation was ≤3%.

[0174] The results are shown in Table 1.

[0175] Table 1 Performance parameters of Examples 1-3 and Comparative Examples 1-9

[0176]

[0177] Using Example 3 as the control group, the performance differences and causes of Comparative Examples 1-9 are analyzed as follows:

[0178] Comparative Example 1 (without graphene-chitosan-grafted β-cyclodextrin composite adsorbent): This comparative example lacks the pollutant enrichment and inclusion functions of the adsorbent, resulting in a significant decline in several core performance characteristics. The COD removal rate decreased from 97.5% in Example 3 to 73.6%, a decrease of 24.5%; the ammonia nitrogen removal rate decreased from 94.2% to 69.8%, a decrease of 25.9%; Cr... 6+ Pb 2+ Cd 2+ The removal rates decreased from 99.4%, 99.6%, and 99.2% to 79.5%, 81.3%, and 80.7%, respectively, with a decrease of over 18% in each case. The effective time of sustained release was shortened from 9.3 h to 4.5 h, a reduction of 51.6%. This is because the graphene component of the composite adsorbent provides an ultra-high specific surface area, the chitosan amino group forms a complex with heavy metal ions, and the hydrophobic cavity of β-cyclodextrin captures recalcitrant organic matter. These three components work synergistically to achieve the "enrichment-locking" of pollutants. Without them, the high concentration of pollutants cannot be provided for subsequent reactions, and the removal effect of heavy metals and organic matter cannot be enhanced. At the same time, the effective components of the agent are rapidly lost, and the sustained release performance is significantly reduced.

[0179] Comparative Example 2 (without magnetically supported cerium-bismuth composite nanocatalyst): This comparative example lost its weak photocatalytic activity and magnetic recovery function, showing a significant difference in key performance characteristics. COD removal rate decreased from 97.5% to 76.8%, a drop of 21.2%; ammonia nitrogen removal rate decreased from 94.2% to 71.5%, a drop of 24.1%; Cr... 6+ Pb 2+ Cd 2+ The removal rates decreased from 99.4%, 99.6%, and 99.2% to 83.7%, 84.5%, and 83.2%, respectively, with a decline of over 15% in each case. The catalyst recovery efficiency plummeted from 91.2% to 12.3%, a decrease of 86.5%. The core reason is that in the magnetically supported cerium-bismuth composite nanocatalyst, the cerium-bismuth composite oxide can efficiently generate free radicals in deep-water, low-light environments, oxidizing and degrading organic pollutants and ammonia nitrogen. The Fe3O4 magnetic core is crucial for catalyst recovery and reuse. Without this component, the catalytic oxidation pathway is disrupted, hindering the removal of ammonia nitrogen and recalcitrant organic matter. Furthermore, the lack of a magnetic support prevents the catalyst from being recovered via electromagnetic separation, resulting in near-complete loss of recovery efficiency.

[0180] Comparative Example 3 (without organic coagulant aid): In this comparative example, only the turbidity removal rate changed by more than 12%, decreasing from 99.5% in Example 3 to 87.3%, a decrease of 12.3%. This is because the molecular chains of the organic coagulant aids (cationic polyacrylamide, polyethylene oxide) can act as bridging agents, connecting the primary flocs generated by conventional flocculants, increasing the floc particle size and density, and accelerating solid-liquid separation. Without this component, the floc structure was loose, the particle size was small, the settling speed was slowed, and the turbidity removal effect was significantly weakened. Other indicators showed smaller changes because they did not involve the floc coagulation efficiency.

[0181] Comparative Example 5 (without slow-release carrier): The slow-release performance and removal efficiency of the core pollutants in this comparative example declined significantly. The ammonia nitrogen removal rate decreased from 94.2% to 81.2%, a drop of 13.8%; the effective slow-release time shortened from 9.3 h to 3.2 h, a reduction of 65.6%. This is because the slow-release carrier (porous diatomaceous earth, expanded perlite) has high porosity, which can adsorb and lock in the active ingredients of the agent, delaying their diffusion and loss in deep water, while also increasing floc density and promoting sedimentation. Without the carrier, the agent is rapidly released and diffuses with the water flow, failing to maintain a long-term effect in the target area, resulting in insufficient reaction time, a decrease in the removal rate of pollutants such as ammonia nitrogen, and a significant shortening of the effective slow-release time.

[0182] Comparative Example 6 (using ordinary montmorillonite instead of graphene-chitosan-grafted β-cyclodextrin composite adsorbent): This comparative example showed significant performance degradation due to insufficient adsorbent structure and functional sites. COD removal rate decreased from 97.5% to 83.5%, a drop of 14.4%; ammonia nitrogen removal rate decreased from 94.2% to 76.9%, a drop of 18.4%; and the effective release time shortened from 9.3 h to 4.8 h, a reduction of 48.4%. Ordinary montmorillonite lacks the ultra-high specific surface area of ​​graphene, the amino complexation sites of chitosan, and the hydrophobic inclusion cavity of β-cyclodextrin, thus failing to achieve efficient enrichment and multiple locking of pollutants. Furthermore, its pore structure and adsorption performance are far inferior to composite adsorbents, leading to a decrease in reagent loading and sustained-release effect, and a significant reduction in both the removal rate of core pollutants and the sustained-release time.

[0183] Comparative Example 7 (using nano-titanium dioxide instead of magnetically supported cerium-bismuth composite nano-photocatalyst): This comparative example shows significant differences in key performance due to catalyst compatibility and lack of magnetism. Ammonia nitrogen removal rate decreased from 94.2% to 80.3%, a drop of 14.8%; catalyst recovery efficiency decreased from 91.2% to 15.6%, a drop of 82.9%. Nano-titanium dioxide exhibits low quantum efficiency and insufficient catalytic oxidation activity in deep-water, low-light environments, failing to effectively degrade ammonia nitrogen and organic pollutants. Furthermore, lacking an Fe3O4 magnetic core, it cannot be recovered by the electromagnetic separation device, leading to severe catalyst loss and a significant decrease in recovery efficiency. Simultaneously, its catalytic degradation effect is weaker than that of cerium-bismuth composite oxide, resulting in a significant reduction in ammonia nitrogen removal rate.

[0184] Comparative Example 8 (Graphene-Chitosan Grafted β-Cyclodextrin Composite Adsorbent without β-Cyclodextrin Grafting Modification): Due to the lack of inclusion function in the adsorbent, several performance characteristics of this comparative example decreased significantly. COD removal rate decreased from 97.5% to 79.8%, a decrease of 18.2%; ammonia nitrogen removal rate decreased from 94.2% to 73.6%, a decrease of 21.9%; Cr... 6+ Pb 2+ Cd 2+ The removal rates decreased from 99.4%, 99.6%, and 99.2% to 85.4%, 86.7%, and 85.9%, respectively, with a decrease of more than 12% in each case. The effective time of sustained release was shortened from 9.3 h to 5.1 h, a reduction of 45.2%. The hydrophobic cavity of β-cyclodextrin is a key structure for capturing recalcitrant organic pollutants. The adsorbent without graft modification only retains the specific surface area of ​​graphene and the amino sites of chitosan, lacking the inclusion function of organic pollutants. This leads to a decrease in pollutant enrichment efficiency. At the same time, the binding ability between the adsorbent and the reagent is weakened, the sustained release performance is reduced, and the removal effect of multiple pollutants is affected.

[0185] Comparative Example 9 (without ultrasonic dispersion during reagent preparation): In this comparative example, due to uneven component composition, the synergistic effect was weakened, and key performance characteristics declined significantly. The ammonia nitrogen removal rate decreased from 94.2% to 82.5%, a drop of 12.4%; the effective sustained-release time shortened from 9.3 h to 7.8 h, a reduction of 16.1%. Ultrasonic dispersion promotes the uniform dispersion of components such as the graphene-chitosan-grafted β-cyclodextrin composite adsorbent and the magnetically supported cerium-bismuth composite nanocatalyst in the system, preventing agglomeration and ensuring sufficient contact between components to form a synergistic structure. Without ultrasonic dispersion, some functional components agglomerated and could not effectively combine with other components, weakening the adsorption-catalysis synergy and flocculation-sustaining-release synergy, resulting in a significant decrease in both the ammonia nitrogen removal rate and the effective sustained-release time.

[0186] In summary, the graphene-chitosan-grafted β-cyclodextrin composite adsorbent enhances pollutant enrichment and locking, while the magnetically supported cerium-bismuth composite nanocatalyst improves weak photocatalytic efficiency and is recyclable. The synergistic effect of these two components increases the removal rate of recalcitrant organic matter by over 20%. Conventional flocculants and organic coagulants optimize floc structure, heavy metal chelators and adsorbents form a triple removal mechanism, and slow-release carriers and oxidizing synergists extend the action time and improve the deep-water environment. The synergistic effect of these components achieves an integrated "adsorption-catalysis-flocculation-slow release-recovery" process, significantly improving the effectiveness and economic efficiency of wastewater treatment.

[0187] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A deep-water wastewater treatment system for river sewage, characterized in that, It includes a pretreatment and interception module, an intelligent and precise dosing module, a gradient reaction module, a solid-liquid separation and recovery module, and an IoT monitoring and control module; By weight, the raw materials of the reagents used in the intelligent precision dosing module include: 40-85 parts of conventional flocculant, 2-6 parts of organic coagulant aid, 12-28 parts of graphene-chitosan grafted β-cyclodextrin composite adsorbent, 8-22 parts of magnetically supported cerium bismuth composite nano-photocatalyst, 4-12 parts of heavy metal chelating agent, 18-45 parts of slow-release carrier, 6-18 parts of oxidation synergist, 3-9 parts of pH adjuster, 7-15 parts of biosynergist, and 2-6 parts of bactericide. Conventional flocculants are composed of polyaluminum chloride and polyferric sulfate in a mass ratio of 1.5:1-2:

1. The organic coagulant aid is cationic polyacrylamide or polyethylene oxide. The heavy metal chelating agent is sodium dithiocarbamate or potassium dithiocarbamate. The slow-release carrier is porous diatomaceous earth or expanded perlite. The oxidation synergist is calcium peroxide or sodium persulfate. The pH adjuster is a sodium bicarbonate-potassium dihydrogen phosphate composite system composed of sodium bicarbonate and potassium dihydrogen phosphate in a mass ratio of 1:1-3:

1. The biosynergist is humic acid or fulvic acid. The bactericide is polyhexamethylene guanidine hydrochloride or polyquaternium-6.

2. The deep-water wastewater treatment system for river wastewater according to claim 1, characterized in that, The raw materials of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent, by weight, include: 6-10 parts graphene powder, 90-100 parts chitosan, 30-50 parts β-cyclodextrin, 3-8 parts glutaraldehyde, 150-200 parts hydrochloric acid solution, 100-150 parts sodium hydroxide solution, and 0.2-0.4 parts sodium dodecyl sulfate.

3. The deep-water wastewater treatment system for river wastewater according to claim 2, characterized in that, The degree of deacetylation of chitosan is 85-90%, the molar concentration of hydrochloric acid solution is 0.5-1.0 mol / L, and the molar concentration of sodium hydroxide solution is 0.5-1.0 mol / L.

4. The deep-water wastewater treatment system for river wastewater according to claim 2, characterized in that, The preparation method of the graphene-chitosan-grafted β-cyclodextrin composite adsorbent includes the following steps: 1) Disperse graphene powder in deionized water to form a solution with a concentration of 0.8-2.0 mg / mL, add sodium dodecyl sulfate, and ultrasonically disperse at 500-700 W power for 40-60 min to obtain a graphene dispersion. 2) Add chitosan to hydrochloric acid solution and stir at 200-300 r / min at 35-45℃ for 30-50 min. Adjust the pH to 5.0-6.0, add β-cyclodextrin, and continue stirring at the same speed for 60-90 min. 3) Slowly add glutaraldehyde to the mixture obtained in 2), stir at 300-400 r / min at 40-50℃ for 2-3 h, then add graphene dispersion, continue stirring at the same speed for 30-40 min, and then ultrasonically disperse for 30-45 min under the conditions of power 400-600W and ultrasonic frequency 20-40kHz. 4) Adjust the pH of the solution obtained in 3) to 7.0-8.0 with sodium hydroxide solution, filter under vacuum, wash with deionized water until neutral after precipitation, dry at 105-120℃ for 5-8 hours, grind to 180-250 mesh to obtain graphene-chitosan grafted β-cyclodextrin composite adsorbent.

5. The deep-water wastewater treatment system for river wastewater according to claim 1, characterized in that, The raw materials of the magnetically supported cerium-bismuth composite nanophotocatalyst, by weight, include: 90-100 parts of bismuth nitrate, 30-80 parts of cerium nitrate, 250-450 parts of citric acid, 50-100 parts of ethylene glycol, 100-140 parts of ferric chloride, 40-60 parts of ferrous chloride, and 100-200 parts of ammonia.

6. The deep-water wastewater treatment system for river wastewater according to claim 5, characterized in that, The preparation method of magnetically supported cerium-bismuth composite nanocatalysts includes the following steps: a. Dissolve ferric chloride and ferrous chloride in deionized water, heat to 75-85℃ under nitrogen protection, stir at 250-350 r / min for 30 min, add ammonia dropwise to adjust the pH to 10-11, continue stirring for 2 h, wash the precipitate three times alternately with deionized water and anhydrous ethanol, and then vacuum dry at 60-70℃ for 12 h to obtain Fe3O4 magnetic particles; b. Disperse Fe3O4 magnetic particles in deionized water to prepare a Fe3O4 dispersion with a concentration of 0.5-1.0 mg / mL; separately, dissolve bismuth nitrate in deionized water at a solid-liquid ratio of 1 g:50 mL to 1 g:100 mL to prepare a bismuth nitrate solution; take cerium nitrate and dissolve it in deionized water at a solid-liquid ratio of 1 g:20 mL to 1 g:30 mL to prepare a cerium nitrate solution. c. Slowly add cerium nitrate solution dropwise to bismuth nitrate solution, stir at 350-550 r / min for 25-40 min, adjust the pH value to 3.5-5.5 with citric acid, and stir at the same speed at 65-85℃ for 150-210 min to form a homogeneous sol. Then, add Fe3O4 dispersion dropwise to the sol at a mass ratio of Fe3O4 magnetic particles to bismuth nitrate of 1:1.2-1.8, and continue stirring at the same speed for 30-40 min. d. The mixture obtained in c is evaporated at 85-95℃ for 5-8h to form a gel, which is then vacuum dried at 105-120℃ for 10-16h. The dried gel is then placed in a muffle furnace and heated to 580-620℃ at a rate of 6-12℃ / min for 3-5h. After that, it is naturally cooled to room temperature and then pulverized to 40-80nm by airflow to obtain a magnetically supported cerium-bismuth composite nanocatalyst.

7. The deep-water wastewater treatment system for river wastewater according to claim 6, characterized in that, The mass fraction of ammonia in the solution is 20-25 wt%.

8. The deep-water wastewater treatment system for river wastewater according to any one of claims 1-7, characterized in that, The preparation method of the reagents used in the intelligent precision dosing module includes the following steps: (1) Add conventional flocculant and pH adjuster to a pressure-resistant mixing vessel in proportion, and stir at 180-280 r / min for 20-30 min at 22-32℃ to form a uniform mixture; (2) Add the slow-release carrier and bio-synergist to the mixture obtained in (1), heat to 45-55℃, stir at 350-450r / min for 40-60min, then add graphene-chitosan grafted β-cyclodextrin composite adsorbent, magnetically supported cerium bismuth composite nanophotocatalyst and heavy metal chelating agent in sequence, stir at 28-38℃ at 300-400r / min for 70-100min; start ultrasonic dispersion when stirring for 30-40min, continue ultrasonication for 30-45min, and keep stirring at 300-400r / min during this period; (3) Add the oxidizing synergist and bactericide to the mixture obtained in (2), stir at 100-150r / min for 25-35min, and finally add the organic coagulant, stir at 60-120r / min for 18-25min to obtain the desired agent.

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