Multi-scene three-dimensional treatment method for heavily polluted lake and reservoir, water purification material and preparation method thereof

Abstract

The present application provides a heavy pollution lake and reservoir multi-scene three-dimensional management method, water purification material and preparation method. In the pollution source inflow area, according to the water inflow characteristics, the detachable modular artificial wetland technology is applied to control the source and intercept the pollution. In the lake shore drawdown zone, the semi-submersible water body pollutant removal technology is applied, the water plants with ecological and economic benefits are screened, and the plants are effectively planted on the floating bed to build an ecological buffer zone. Through the characteristics of short crop growth period and high nutrient demand, the rapid adsorption and removal of eutrophication pollutants are realized, and economic output is realized. In the overlying water area, based on the water purification treatment effect of the material, the suspended depth treatment technology of the polluted lake and reservoir water body is applied to realize the in-situ removal of pollutants in different depths of the lake and reservoir. In the lake and reservoir sediment area, based on the water purification treatment effect of the material, the recyclable lake and reservoir sediment technology is applied to achieve the enrichment and removal of pollutants in the lake and reservoir sediment.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of ecological protection, and particularly relates to a multi-scene three-dimensional treatment method for heavily polluted lakes and reservoirs, a high-efficiency water purification material based on natural minerals and a preparation method thereof. BACKGROUND

[0002] With the development of social economy, lake and reservoir pollution is fully exposed and increasingly prominent, which has become one of the major problems faced by global water environment. The main causes of lake and reservoir pollution include two sources of exogenous input and endogenous release, excessive enrichment of nitrogen, phosphorus, organic matter and other substances, leading to continuous accumulation of pollutants. In view of the formation mechanism of lake and reservoir pollution, pollution control and engineering application and other problems, domestic and foreign scholars have carried out a large number of explorations, and formed the pollution control idea of lake and reservoirs with "exogenous pollution interception-endogenous treatment-ecological reconstruction" as the core. The specific treatment technology is mainly divided into physical method, chemical method and ecological method. For exogenous input, while improving the sewage treatment rate and perfecting the supporting pipe network, the focus is on strengthening management, and for endogenous release, methods such as in-situ passivation, exchange adsorption, sediment dredging or covering and ecological reconstruction are mainly adopted.

[0003] Controlling source and intercepting pollution is the premise and foundation of lake and reservoir water environment treatment, which mainly controls the exogenous pollution input of heavily polluted lakes and reservoirs from the source, especially the input of pollutants with high nitrogen and phosphorus content. By screening water plants with strong absorption capacity, large growth and strong adaptability, lake (shore) belt construction such as lake shore buffer zone, ecological interception zone and artificial wetland can be carried out to integrate technologies, so as to intercept most of the exogenous pollutants. However, the maintenance cost of ecological pollution interception measures is high, and the follow-up management is difficult to continue. If ecological and economic benefits can be considered, it is more conducive to the sustainable operation of the source control and pollution interception project.

[0004] One of the most commonly used technologies for endogenous treatment is in-situ passivation. Compared with lake endogenous phosphorus treatment methods such as environmental dredging and plant remediation, in-situ passivation technology has the advantages of simple operation and efficient treatment, which has attracted widespread attention. By adding passivation agent to the polluted water body, a passivation agent layer is formed at the sediment-water interface, which blocks the release of phosphorus in the sediment to the overlying water and prevents eutrophication. Commonly used passivation agents can be divided into aluminum-based and calcium-based passivation agents according to their effective components. The medium active phosphorus combined with aluminum-based passivation agent will be released when the PH increases, resulting in poor passivation effect, and the dissolution of Al 3+ will also poison aquatic organisms; although the combination product of calcium-based passivation agent with phosphorus is stable, the solubility product of Ca 2+ and PO4 3- is large, so the passivation effect is limited. At the same time, this technology cannot be recycled after adding the reagent, and the characteristic pollutants such as nitrogen, phosphorus and heavy metals passivated and locked cannot be completely removed from the water body, so it is difficult to fundamentally control the pollution of lake and reservoir water body.

[0005] Ecological reconstruction is an important guarantee for realizing the "stable and clear water state" of lake and reservoir water quality. It mainly uses biological manipulation theory to adjust the water quality and ecological monitoring of aquatic organisms and their habitats to enhance certain interactions. Ecological reconstruction can significantly improve eutrophic water bodies by using water body segmentation technology, benthic animal expansion technology, artificial attached medium technology, and aquatic vegetation restoration technology. Practice has proved that physical or chemical methods, including adding inhibitors, controlling pH, and increasing dissolved oxygen (DO) to inhibit the release of phosphorus in the sediment, can improve the benthic habitat and improve water quality in the short term, but the sustainability is poor. Therefore, it is necessary to combine ecological reconstruction technology to make the most of it.

[0006] Reference [1] Hu Chuanlin. Promote the coordinated governance of rivers, lakes and reservoirs to help win the battle of protecting and restoring the Yangtze River [J]. China Environmental Supervision, 2022, No. 79 (11): 30-32.

[0007] Reference [2] Ye Chun, Li Chunhua, Wang Bo, et al. Discussion on the construction scheme of healthy aquatic ecosystem of Hongze Lake [J]. Lake Science, 2011, 23 (05): 725-730.

[0008] Reference [3] Yi Zhongqiang, Liu Defu. Research on ecological restoration of eutrophic lakes and reservoirs [J]. China Rural Water Resources and Hydropower, 2010, No. 332 (06): 26-29.

[0009] Reference [4] Qin Boqiang. Basic principles and realization of lake ecological restoration [J]. Acta Ecologica Sinica, 2007 (11): 4848-4858.

[0010] Reference [5] Gu Binhe. Eutrophication and ecological restoration of Apopka Lake in the United States [J]. Lake Science, 2005 (01): 1-8.

[0011] From references [1]-[5], the past experience of lake management shows that:

[0012] In the process of ecological reconstruction of eutrophic lakes and reservoirs, the single application or interactive application of biological measures and engineering measures has achieved some results, but it is still in the stage of theoretical exploration and preliminary attempt. Aquatic plants are greatly affected by season and temperature. In low temperature conditions, plant growth is slow, and the activity of plant root enzymes and microorganisms is also low. If the plants are not treated in the water body in winter, they may wither and rot, which may pollute the water body again. Therefore, the modularization of aquatic plant carriers should be considered to facilitate replacement. Aquatic plant planting carriers mainly include high molecular carriers and inorganic filter carriers. Both types of carriers have certain shortcomings, such as secondary pollution caused by organic carriers and poor stability of inorganic carrier technology. Therefore, new application technologies should be actively sought.

[0013] In terms of material selection, lanthanum / cerium rare earth water treatment agents have gained increasing attention in recent years. Rare earth elements have special properties such as paramagnetism, catalysis, and multi-way coordination. After treatment such as calcination, catalysis, and super magnetism, their structural properties can be changed to become functional materials with catalytic, adsorptive, and ion exchange properties. For example, La 3+ The solubility product of the precipitate LaPO4 formed with PO4 3- is 10 -24.7 , which is the smallest among the solubility products of phosphates, indicating that lanthanum-based materials can achieve the maximum control of phosphorus, and the LaPO4 precipitate is very stable, with a long-lasting and effective passivation effect. Lanthanum-modified bentonite (LMB) has strong selective adsorption and good biological compatibility, and is increasingly concerned in the control of the release of endogenous pollutants. Adsorbent materials prepared based on cerium oxide show strong adsorption capacity for various harmful anions such as phosphates, arsenates, fluorides, and dichromates. Therefore, developing efficient water purification materials based on lanthanum, cerium, and other rare earth elements can become a new approach to in-situ remediation of heavily polluted lake and reservoir water bodies.

[0014] [6] Chen, M. K., Jiang, Y. H., Cheng, R. X., et al. Locking effect of Zn-Al-La-LDHs modified bentonite on phosphorus in eutrophic lakes[J]. Chinese Journal of Environmental Engineering, 2022, 16(06): 1823-1832.

[0015] [7] Lin, J., Yao, J. W., Wei, X., et al. Adsorption characteristics, mechanism and influencing factors of lanthanum-modified bentonite for phosphorus[J]. Environmental Science and Technology, 2021, 44(01): 7-12. DOI:10.19672 / j.cnki.1003-6504.2021.01.002.

[0016] [8] Cheng, Y. Research on rare earth-based composite materials for water phosphorus removal[D]. University of Science and Technology of China, 2021. DOI:10.27517 / d.cnki.gzkju.2021.001256.

[0017] [9] Cui, Y. W., Li, J., Du, Z. F. Comparative study on the performance and mechanism of lanthanum and cerium modified zeolites for phosphorus removal from wastewater[J]. Chinese Journal of Rare Metals, 2016, 34(04): 460-468.

[0018]

[10] Huo, H. X., Lin, H., Dong, Y. B., et al. Effect of calcination modification on the characteristics of zeolite and its performance for removing ammonia nitrogen[J]. Journal of Northeastern University(Natural Science), 2013, 34(12): 1778-1782.

[0019] However, these new materials also have certain limitations. For example, lanthanum hydroxide adsorbent has poor dispersibility in water, is easy to aggregate, and the product after reacting with phosphate is easy to form a mixture with sludge in sewage, which is difficult to separate, thereby causing the adsorbent material to be unable to be recycled and reused, and also possibly causing secondary pollution to water quality. Rare earth elements such as lanthanum and cerium can be dispersed on the surface of solid materials to increase the specific surface area, thereby improving the adsorbability of the composite material. Therefore, in order to achieve the important goal of lake and reservoir water pollution prevention and control, it is urgent to create materials and innovate application processes for comprehensive treatment of heavily polluted lakes and reservoirs. SUMMARY

[0020] The present application aims to solve the defects of the prior art, and provides a multi-scene three-dimensional treatment method for heavily polluted lakes and reservoirs, a water purification material and a preparation method.

[0021] The present application is a multi-scene three-dimensional treatment method for heavily polluted lakes and reservoirs, based on a composite functional water purification material loaded with rare earth elements such as lanthanum and cerium on natural minerals, and simultaneously developing a recyclable application package innovation process, breaking through the bottleneck of non-recyclable water purification materials in traditional treatment modes, enhancing water purification efficiency while reducing safety hazards; starting from the perspective of hydrogeology, based on the "system" thought and method, forming a high-efficiency multi-scene three-dimensional comprehensive treatment technology system for heavily polluted lakes and reservoirs based on materials, reshaping the ecological balance of "plants-microorganisms-aquatic animals", and ensuring the long-term stability of the improvement points of the water quality of heavily polluted lakes and reservoirs. A set of targeted, site-specific, and scientific and reasonable treatment system solution for heavily polluted lakes and reservoirs is formed, ensuring that the water quality in the area is stable above the Class IV standard for a long time, and maintaining above the Class III standard in summer, providing a demonstration model for the treatment of heavily polluted lakes and reservoirs, and providing technical support for the comprehensive treatment of the water environment of heavily polluted lakes and reservoirs.

[0022] The present application adopts the following technical solutions:

[0023] The preparation method of the iron-carbon modified filler comprises

[0024] The iron-carbon modified filler is manufactured by high-temperature calcination.

[0025] 2g of iron powder and 2g of activated carbon powder are taken as raw materials, 1g of bentonite and 1g of zeolite powder are taken as binders, and a small amount of additives is added, the additives include modified materials of rare earth elements (lanthanum or cerium) and pore-forming agents (ammonium bicarbonate or ammonium chloride), 0.2g of each of the modified materials of rare earth elements and the pore-forming agents is taken, and then 100mL of deionized water is added multiple times for mixing, manual granulation is performed, then drying is performed in an oven at a temperature of 90℃ for 30min, natural cooling is performed, and then the iron-carbon modified filler is obtained by high-temperature calcination in a muffle furnace for 2h.

[0026] A multi-scene three-dimensional treatment method for heavily polluted lakes and reservoirs mainly comprises:

[0027] In the pollution source inflow area, based on the characteristics of the inflow, detachable modular constructed wetland technology is applied to control pollution sources and intercept wastewater.

[0028] In the drawdown zone of the lake shore, semi-submersible water pollutant removal technology is applied to select aquatic plants that offer both ecological and economic benefits. These plants are then effectively planted on floating beds to create an ecological buffer zone. Leveraging the short growing season and high nutrient requirements of these crops, rapid adsorption and removal of eutrophic pollutants are achieved, while simultaneously generating economic output.

[0029] In the overlying water area, based on the water purification effect of the materials, the suspended fixed-depth treatment technology for polluted lake and reservoir water is applied to achieve in-situ removal of pollutants in water at different depths in the lake and reservoir.

[0030] In the lake and reservoir bottom sediment area, based on the water purification effect of the materials, the application of recyclable lake and reservoir sludge technology can achieve the goal of enriching and removing pollutants from the lake and reservoir bottom sediment.

[0031] The key effects of this invention, namely, a multi-scenario three-dimensional treatment method for heavily polluted lakes and reservoirs, mainly include the following two points:

[0032] (1). Recyclable application technology of high-efficiency water purification materials based on natural minerals

[0033] 1) Material Preparation: Currently used natural mineral materials for water treatment include zeolite, bentonite, and clay, which typically lack effective adsorption sites and have poor hydrophobicity. This invention loads different proportions of rare earth elements such as lanthanum and cerium onto natural mineral materials through calcination and other methods, significantly improving the material's adsorption, antibacterial, catalytic, and ion exchange performance, creating an economical, efficient, and universally applicable lanthanum / cerium-based mineral water purification material. Through a 60-hour static adsorption experiment, the lanthanum and cerium-based iron-carbon modified filler in the module reduced the TN and TP concentrations in water bodies with different levels of pollution by 19.30%-56.39% and 17.48%-89.21%, respectively.

[0034] 2) Recycling process: By designing and deploying material enrichment and removal modules, in-situ water purification is achieved in water and sediment at different depths through suspension, submersion, and embedding methods, enabling recyclability. This forms a new process for the application of water purification materials and is one of the core technologies. Compared with other passivation materials, it can effectively remove pollutants from water bodies, rather than temporarily locking them in, thus avoiding secondary pollution during water treatment.

[0035] (2) Integration of multi-scenario three-dimensional treatment technologies for polluted lakes and reservoirs

[0036] The heavy pollution lake and reservoir water ecosystem is usually unbalanced or unstable. The water quality purification effect cannot be long-acting maintained by simply adopting the method of treating a water body position of the lake and reservoir. The heavy pollution lake and reservoir water ecosystem is recognized and researched from the perspective of hydrogeology, the treatment units of different positions of the lake and reservoir are generalized as loose porous water-containing media for pollution and pollution removal, and the multi-scene three-dimensional treatment technology of the lake and reservoir is finally integrated according to the hydrological process and the hydraulic conditions of different positions in the scenes of the lake and reservoir inlet, the lake bank, the lake and the lake bottom, which is a method and practice innovation for realizing the comprehensive treatment of the heavy pollution lake and reservoir. Meanwhile, the removable treatment units of different positions of the lake and reservoir can be used in the modularization, so that the rapid recovery of the matrix function in the removable unit can be ensured, and the operation life of the pollution lake and reservoir treatment project is prolonged.

[0037] The beneficial effects of the present application are as follows:

[0038] The water environment in China is getting better year by year, but the water quality of some lakes and reservoirs is still deteriorating, forming heavy pollution, which seriously threatens the safety of the source water and groundwater. In the face of the high difficulty, complexity, urgency and long-term nature of the heavy pollution lake and reservoir treatment, the popular pollution lake and reservoir treatment technology has obvious deficiencies in suitability, stability, systematicness and operability. It is necessary to further create efficient water quality purification materials and break through the technical bottleneck that the water treatment materials cannot be recycled after being put into the water, so that the characteristic pollutants can be effectively removed from the water body. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1 The idea of the present application is shown in the figure;

[0040] Figure 2 The schematic diagram of the present application is shown in the figure;

[0041] Figure 3 The schematic diagram of the detachable constructed wetland treatment unit is shown in the figure;

[0042] Figure 4 The schematic diagram of the equilateral hexagonal module frame is shown in the figure;

[0043] Figure 5 The schematic diagram of the semi-submersible water body pollutant removal unit device is shown in the figure;

[0044] Fig. 6 (a) is a top view of the buoyancy controller;

[0045] Fig. 6 (b) is a sectional view of the buoyancy controller;

[0046] Figure 7 The schematic diagram of the recyclable medicine bag structure is shown in the figure;

[0047] Figure 8 The schematic diagram of the lanthanum and cerium-based iron-carbon modified filler is shown in the figure;

[0048] Figure 9(a) is a scanning electron microscope image of lanthanum-based iron-carbon modified filler;

[0049] Figure 9(b) is a scanning electron microscope image of cerium-based iron-carbon modified filler;

[0050] Figure 10 Figure 10 is a schematic diagram of the action mechanism of lanthanum and cerium-based iron-carbon modified filler;

[0051] Figure 11 Figure 11 is a schematic diagram of a suspended depth treatment device for a polluted lake and reservoir water body;

[0052] Figure 12 Figure 12 is a schematic diagram of a recyclable lake and reservoir sludge treatment device;

[0053] Figure 13 Figure 13 is a schematic diagram of a sludge treatment device. DETAILED DESCRIPTION

[0054] In order to make the purpose, technical solutions and advantages of the present application clearer, the technical solutions in the present application are described clearly and completely below. Obviously, the described embodiments are part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0055] The present application is based on the characteristics of the developed materials and the innovative application process, combined with the theory of hydrogeology, fully utilizing the mechanism of water-rock interaction, and integrating a multi-scenario three-dimensional treatment method for heavily polluted lakes and reservoirs, mainly including:

[0056] In the pollution source and sink inflow area, according to the characteristics of the inflow water, a detachable modular constructed wetland technology is applied to control the source and intercept the pollution.

[0057] In the lake shore drawdown zone, a semi-submersible water pollutant removal technology is applied, and aquatic plants with both ecological and economic benefits are screened, and the plants are effectively planted on the floating bed to build an ecological buffer zone. Through the characteristics of short crop growth period and high nutrient demand, the rapid adsorption and removal of eutrophication pollutants are realized, and economic output is also realized.

[0058] In the overlying water body area, based on the water purification treatment effect of the material, a suspended depth treatment technology for polluted lake and reservoir water body is applied to realize in-situ removal of pollutants in different depths of lake and reservoir water body.

[0059] In the lake and reservoir sediment area, based on the water purification treatment effect of the material, a recyclable lake and reservoir sludge technology is applied to achieve the enrichment and removal of pollutants in lake and reservoir sediment.

[0060] Finally, a balanced ecological system of "plant-microorganism-aquatic animal" is constructed, and a set of multi-scenario three-dimensional comprehensive treatment technology for heavily polluted lakes and reservoirs is formed (as shown in Figure 2 ).

[0061] (1) Pollution source inflow area - detachable constructed wetland unit

[0062] This zone mainly uses detachable constructed wetland devices (such as shown in Figure 3 ), through the physical, chemical, and biological synergistic effects of the microbial, plant, and artificial substrate composite ecosystem, to treat sewage and sludge, control source pollution, and preliminarily remove characteristic pollutants. The land area of the detachable constructed wetland unit can be set according to the actual situation of the inflow area, and is usually 50 m in length, with a length-width ratio controlled below 3:1, and a water slope set at 0.5%-1%. A purification tank can be set before the inlet of the constructed wetland unit to effectively remove solid waste carried by the water body and ensure stable water inflow velocity. The detachable constructed wetland unit is composed of more than one regular hexagonal module, including a module frame and a substrate filler (such as shown in Figure 4 ).

[0063] 1) Module frame

[0064] The module frame is a regular hexagonal column with a side length of 300 mm and a height of 350 mm, which ensures that the water flow direction is not parallel to the gap between the modules, so that the water flow can flow more fully in the module substrate pores. Considering the operation, cost, and maintenance of the wetland system, a certain bearing capacity, corrosion resistance, and economic material are selected, and the structural material is non-toxic and harmless, meeting the mechanical property requirements of engineering PVC as the module frame. To ensure that the water flow in the constructed wetland flows smoothly through the module, dense holes need to be punched around the engineering PVC frame and the bottom, with each side hole having a diameter of 1-5 mm, ensuring that the water flow between the modules is in a turbulent state, and avoiding substrate blockage in a long-term laminar state.

[0065] 2) Filling substrate

[0066] The substrate is laid from bottom to top in the order of limestone and river sand. The limestone filler layer is 30 cm thick, with a particle size range of 0.5 cm-1 cm; the river sand layer is 5 cm thick, with a particle size of about 0.05 cm. According to the actual application situation, landscape plants can be planted in the substrate.

[0067] (2) Lake shore drawdown zone - semi-submersible water pollutant removal unit

[0068] This area mainly uses semi-submersible water pollutant removal devices (such as shown in Figure 5 ), to realize the three-dimensional space water environment improvement of the lake and reservoir shore water and sediment, reduce the content of eutrophic pollutants and heavy metals in the water body and sediment, continuously improve the water quality of the water body, and at the same time realize economic output. The main body of the device is composed of a detachable buoyancy controller, a recyclable medicine bag, and plants planted in a single module of the buoyancy controller.

[0069] 1) Buoyancy controller

[0070] The buoyancy controller is composed of several buoyancy controller modules (as shown in Figures 6(a) and 6(b)). Each buoyancy controller module has a cuboid structure with dimensions of 300mm (length), 300mm (width), and 100mm (height). The module has connection holes on its surface, multiple small circular holes on its bottom, and a placement hole in the center with dimensions of 250mm (length), 250mm (width), and 100mm (height). A planting basket, 180-220mm high, is movably placed within the hole. Multiple small circular planting holes are evenly distributed on the sides and bottom of the planting basket, which contains a medicine packet and plants.

[0071] 2) Recyclable medicine packs

[0072] To avoid secondary pollution caused by packing leakage and to facilitate later recycling, the calcined packing material is bagged in PVC mesh bags and then placed into individual modules (pharmaceutical bags). Figure 7 (As shown). The medicine bag has a cylindrical structure, approximately 5cm in diameter and 10cm in height. The surface of the cylinder is designed with plum blossom-shaped micropores, each approximately 5mm in diameter, to allow the internal filler to fully react with the water. Connecting rings are located on the top and bottom of the cylinder, allowing for series connection via nylon ropes. Filter paper is placed on the inner sidewalls of the medicine bag to prevent the filler material from leaking out.

[0073] 3) Internal filling material of the medicine pack

[0074] Iron-carbon modified filler was manufactured using a high-temperature calcination method. Iron powder and activated carbon powder were used as the main raw materials (material ratio 1:1), with natural minerals such as bentonite and zeolite powder as binders, and a small amount of additives were added, including rare earth elements (lanthanum or cerium) as modifying materials and pore-forming agents (ammonium bicarbonate or ammonium chloride) (in this scheme, the modifying materials and pore-forming materials were mixed in a 1:1 ratio; no other ratio tests were conducted). Small amounts of deionized water were added repeatedly and mixed thoroughly. The mixture was then artificially granulated (to approximately 1 cm in size into spheres), placed in an oven, and dried at 90°C for about 30 minutes. After natural cooling, it was calcined in a muffle furnace for about 2 hours. After natural cooling, the iron-carbon modified filler (such as...) was obtained. Figure 8 Figure 9(a), Figure 9(b) Figure 10 (As shown).

[0075] 4) Plants

[0076] Plants are generally selected based on purification capacity, local species, low temperature conditions, and root oxygen secretion capacity. The device is based on the above principles to screen aquatic crops (such as rice) with both ecological and economic benefits. The device takes advantage of the short growth period and high nutrient demand of crops to achieve rapid adsorption and removal of eutrophic pollutants, while also achieving economic output. The crops are planted in a single module of the buoyancy controller, with the roots entering the sludge by about 1 / 5-1 / 2, facilitating the harvesting of the roots.

[0077] (3) Lake and reservoir overlying water area - suspended depth treatment unit for polluted lake and reservoir water

[0078] This area mainly uses a suspended depth treatment device for polluted lake and reservoir water, which can effectively reduce the content of eutrophic pollutants and heavy metals in different depths of lake and reservoir water, and continuously improve the water environment of the lake and reservoir in the long run. As shown in Figure 11 , the device is composed of an upper detachable ecological floating bed and a lower recyclable medicine bag, connected by a fine nylon rope. The upper floating bed includes detachable buoyancy controllers, planting baskets, and plants, and the lower recyclable medicine bag is connected by a nylon rope.

[0079] 1) Buoyancy controller, planting basket, and plant

[0080] Consistent with the design of the semi-submersible water pollutant removal device.

[0081] 2) Recyclable medicine bag and filler

[0082] Consistent with the design in the semi-submersible water pollutant removal device.

[0083] The recyclable medicine bag is suspended below the floating bed module and is an important part of the treatment of polluted lake and reservoir water. It adopts a "bead-like" structure, connected by a Φ5mm nylon rope. According to the concentration of pollutants in the lake and reservoir water and the treatment capacity of a single medicine bag, the distance h between two medicine bags can be designed to be 1-5m, achieving the purpose of treating polluted water at a fixed depth. The distance h between two medicine bags of different bead-like structures is 0.5m offset (as shown in Figure 11 ), so that the medicine bag can fully treat polluted water at different depths.

[0084] (4) Lake and reservoir sludge area - recyclable lake and reservoir sludge treatment unit

[0085] The main design of this area is a recyclable lake and reservoir sludge treatment device. This device can achieve the goal of removing pollution and enrichment of lake and reservoir sludge, ultimately reducing eutrophic pollutants and heavy metals in water and improving water quality. As shown in Figure 12 , the main body of the device is a floating bed, which is specifically composed of a buoyancy control module, a recyclable material bag, plants planted in a single module, and a sludge treatment device.

[0086] 2) Buoyancy controller, recyclable medicine pack, plant

[0087] The design is consistent with that of the buoyancy controller in a semi-submersible water pollutant removal device.

[0088] 2) Sludge treatment

[0089] The sludge processor is a key component of this device, mainly consisting of a conical outer shell, an internal material package, and packing material. The conical outer shell is made of PVC material. Figure 13 As shown. The bottom circle has a radius of 25-30cm and a height of 30cm. The outer shell is designed with a plum blossom-shaped perforation pattern, with a hole diameter of 1-2cm, to facilitate the contact and reaction between the internal enrichment material and the bottom sediment. A suspension ring is designed on the upper part of the outer shell for easy secondary recovery of the device. The device is connected by a waterproof and corrosion-resistant nylon rope and suspended from a buoyancy control module. After the device naturally sinks to the interface between the bottom sediment and the water, it partially sinks into the bottom sediment due to gravity. As the bottom sediment increases, it will gradually cover the device. After a period of contact and reaction with the bottom sediment, the enrichment material in the device can gradually enrich the pollutants in the sediment. After a reaction period, the enrichment material is recovered and treated using a connecting device before being placed back into the bottom sediment.

[0090] Example

[0091] Using the process of this invention, water pollutant treatment experiments were conducted on an artificial wetland experimental platform built by Chengdu University of Technology in Jingnan Wetland Park, Deyang City. Under different influent flow rates, water flow stagnation times, and different levels of water pollution, the COD removal efficiency ranged from 16.5% to 38.06%, the NH3-N removal efficiency from 23.34% to 40.59%, the TN removal efficiency from 22.05% to 40.23%, and the TP removal efficiency from 43.93% to 50.94%. The effluent quality met the Class III standard of the "Surface Water Environmental Quality Standard" (GB3838-2002).

[0092] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; 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; and these 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 multi-scene three-dimensional treatment method for heavily polluted lakes and reservoirs, characterized in that, Comprise: Step 1. The pollution source inflow area mainly uses detachable constructed wetland devices to treat sewage and sludge through the physical, chemical and biological synergistic effects of microbial, plant and artificial substrate complex ecosystems, controls source pollution and preliminarily removes pollutants; Step 2. The lake shore drawdown zone mainly uses semi-submersible water pollutant removal devices to reduce the content of eutrophic pollutants and heavy metals in water and sediment, continuously improve water quality, and achieve economic output; The semi-submersible water pollutant removal device is composed of detachable buoyancy controllers, recyclable medicine bags and plants planted in the detachable buoyancy controllers: 1) detachable buoyancy controller The detachable buoyancy controller is composed of a plurality of buoyancy controller modules, and the buoyancy controller module is a cuboid structure with a length, width and height of 300mm, 300mm and 100mm. The buoyancy controller module is provided with a connecting hole, a plurality of circular fine holes at the bottom, and a placement hole with a length, width and height of 250mm, 250mm and 100mm. The placement hole is movably provided with a planting basket, and the planting basket has a height of 180-220mm. The side and bottom surfaces of the planting basket are uniformly provided with a plurality of circular fine holes. The recyclable medicine bag and the plant are arranged in the planting basket; 2) recyclable medicine bag The prepared filler is packed in a single medicine bag with a PVC mesh bag, and the medicine bag is a cylindrical structure with a diameter of Φ5cm and a height of 10cm. The surface of the cylinder has a plum blossom-shaped fine hole with a diameter of Φ5mm. The upper and lower surfaces of the cylinder are provided with connecting rings connected by nylon ropes. A filter paper is placed on the inner side wall of the medicine bag; 3) medicine bag filler Take 2g of iron powder and activated carbon powder as raw materials, 1g of bentonite and 1g of zeolite powder as adhesive, and add additives including modified materials and pore-forming agents, 0.2g of modified materials and pore-forming agents, and then add 100mL of deionized water several times to mix uniformly. Artificial granulation, then placed in an oven at 90℃ for 30min, natural cooling, then put into a muffle furnace for high temperature calcination for 2h, after natural cooling, get iron-carbon modified material, modified material is rare earth element lanthanum or cerium, pore-forming agent is ammonium bicarbonate or ammonium chloride; Step 3. The overlying water body area of the lake and reservoir mainly uses suspended fixed depth treatment devices to effectively reduce the content of eutrophic pollutants and heavy metals in different depths of water in the lake and reservoir, and continuously improve the water environment of the lake and reservoir in the long-term operation; The suspended fixed depth treatment device is composed of an upper detachable ecological floating bed and a lower recyclable medicine bag, and the two are connected by a thin nylon rope. The upper detachable ecological floating bed includes a detachable buoyancy controller, and the lower recyclable medicine bag is connected by a nylon rope; Step 4. The lake and reservoir sediment area uses recyclable lake and reservoir sludge treatment devices, which can achieve the goal of removing pollution and enrichment of lake and reservoir sediment, ultimately reduce eutrophic pollutants and heavy metals in water, and improve water quality; The recyclable lake and reservoir sludge treatment device comprises a detachable buoyancy controller and a sludge treatment device: The sludge processor is composed of a conical shell, an internal material bag and a filler, wherein the conical shell is made of PVC material, the bottom circle radius is 25-30 cm, the height is 30 cm, the shell is designed with plum blossom holes with a hole diameter of 1-2 cm, the upper part of the shell is designed with a hanging ring, the hanging ring is connected with a waterproof and corrosion-resistant nylon rope, and the hanging ring is hung on a detachable buoyancy controller; After the sludge processor naturally sinks to the interface between the bottom mud and the water body, it can partially sink into the bottom mud due to gravity, and as the bottom mud increases, the sludge processor will gradually cover the bottom mud. After the enrichment material in the sludge processor contacts and reacts with the bottom mud for a period of time, it gradually enriches the pollutants in the bottom mud.

2. The multi-scene three-dimensional treatment method for heavily polluted lake and reservoir according to claim 1, characterized in that, The land occupation scale of the detachable artificial wetland device is set according to the actual situation of the pollution source inflow area, the length is 50 m, the length-width ratio is controlled to be less than 3:1, and the hydraulic slope is set to 0.5%-1%. A purification tank is arranged in front of the entrance of the detachable artificial wetland device.

3. The multi-scene three-dimensional treatment method for heavily polluted lake and reservoir according to claim 1, characterized in that, The detachable artificial wetland device is composed of more than one equilateral hexagonal module, which includes a module frame and a substrate filler, and the substrate filler is placed in the module frame: 1) Module frame The module frame is an equilateral hexagonal column with a side length of 300 mm and a height of 350 mm, and the material is PVC. The module frame is perforated around and at the bottom, and the diameter of each side hole is different, ranging from 1 mm to 5 mm. 2) Filling substrate The substrate is laid from bottom to top in the following order: limestone, river sand, limestone filler layer thickness is 30 cm, particle size range is 0.5 cm-1 cm; river sand layer thickness is 5 cm, particle size is 0.05 cm, and landscape plants are planted in the substrate.

4. The multi-scene three-dimensional treatment method for heavily polluted lake and reservoir according to claim 1, characterized in that, The recyclable package of the suspended depth treatment device contains fillers; 1) The detachable buoyancy controller of the suspended depth treatment device is the same as that in the semi-submersible water body pollutant removal device; 2) The recyclable package and filler of the suspended depth treatment device are the same as those in the semi-submersible water body pollutant removal device; The recyclable package of the suspended depth treatment device is suspended under the floating bed and is an important part of the treatment of water body pollutants in the lake. It adopts a "bead-like" structure and is connected by Φ5 mm nylon ropes. According to the concentration of water body pollutants in the lake and the treatment capacity of a single package, the distance h between two packages is 1-5 m, achieving the purpose of treating polluted water bodies at a certain depth. The two packages of different beads have a 0.5 m offset, so that the packages can fully treat polluted water bodies at different depths.

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