Photocatalysis-based comprehensive water treatment method

Abstract

The present application discloses a comprehensive water body treatment method based on photocatalysis, which includes: conducting a water quality investigation on the water body to be treated to determine key water quality purification factors; determining the configuration strategy of treatment facilities according to the environmental conditions of the water body to be treated; monitoring the key water quality purification factors after configuring the treatment facilities in the water body to be treated; judging that the change trend of the key water quality purification factors deviates from the treatment target, and adjusting the configuration strategy of the treatment facilities; confirming that the water body to be treated reaches the treatment target, and withdrawing the treatment facilities. Before laying the treatment facilities, the method of the present application conducts water quality investigation and environmental investigation to determine key water quality purification factors, and conducts targeted design on the layout of treatment facilities, especially the photocatalytic network, so as to achieve the effects of short-term water quality improvement, medium-term ecological restoration and long-term self-cleaning and healing.

Description

Technical Field

[0001] This application relates to the field of sewage treatment, and particularly to a comprehensive water body treatment method based on photocatalysis. Background Art

[0002] Facing the current situation of water body pollution and the continuously expanding list of pollutants, the existing water body treatment methods have not been able to well solve the problem of water body pollution. Here, the water bodies mainly refer to the water bodies with certain functions serving the city, such as the water bodies serving as drinking water sources and the water bodies serving as landscape facilities. In terms of form, it involves ponds, sewage ponds, oxidation ponds, lakes, water sources, wetlands, slow-flowing rivers, dead-end canals, etc. Since the fluidity of these water bodies is poor, the self-purification cycle is less than that of open water bodies with strong fluidity, and there may still be pollutant inputs after water quality treatment, making it difficult to maintain stable water quality for a long time. Once pollution occurs again, it is necessary to re-invest in treatment, and green development has not been achieved.

[0003] The existing water body treatment methods are mainly divided into single means (physical, chemical, and biological) treatment and composite means treatment. However, the goal of ecological environment protection treatment has not been achieved. Summary of the Invention

[0004] The purpose of this application is to overcome the deficiencies of the prior art and provide a comprehensive water body treatment method based on photocatalysis that meets the requirements of ecological environment protection treatment and green development.

[0005] To achieve the above technical objectives, the technical solution adopted in this application is as follows:

[0006] A comprehensive water body treatment method based on photocatalysis, which includes the following steps:

[0007] Conduct a water quality survey on the water body to be treated and determine the key water quality purification factors;

[0008] According to the environmental conditions of the water body to be treated, determine the configuration strategy of the treatment facilities;

[0009] After configuring the treatment facilities in the water body to be treated, monitor the key water quality purification factors;

[0010] Judge that the change trend of the key water quality purification factors deviates from the treatment target, and adjust the configuration strategy of the treatment facilities;

[0011] Confirm that the water body to be treated reaches the treatment target, and withdraw the treatment facilities.

[0012] Specifically, the water body to be treated meets at least one of the following conditions:

[0013] The solar irradiance on the water surface is greater than 10,000 Lux; the water flow velocity is not greater than 0.5 m / s; the water flow velocity not greater than 0.5 m / s is maintained for more than 4 days; the water depth is greater than 0.5 m; the air pollution degree in the upwind area of the water surface is below the preset value; the annual wind force on the water surface is level 1 to 4; the water body is an unnavigable closed water body or semi-closed water body.

[0014] Furthermore, conduct a water quality investigation on the water body to be treated to determine the key water quality purification factors, including:

[0015] Set up a treatment area in the water body to be treated;

[0016] During the treatment time, collect the detection data of the water quality indicators in the treatment area under different water flow states respectively;

[0017] Screen out the key research indicators from all the water quality indicators as the key water quality purification factors.

[0018] Even further, the treatment area includes a net-laying area where a photocatalytic net is laid and a control area; during the treatment time, collect the detection data of the water quality indicators under the following conditions in sequence:

[0019] Collect the detection data of all the water quality indicators in the static flow state, and screen out the initially screened water quality indicators with detected values;

[0020] Collect the detection data of the initially screened water quality indicators respectively in the micro-flow state and the state of water body disturbance, and screen out the reference water quality indicators with significantly changed detected values;

[0021] Screen out the key water quality indicators from the reference water quality indicators as the key water quality purification factors.

[0022] Preferably, the number of the key water quality indicators is not less than 50% of the number of the reference water quality indicators.

[0023] Optionally, the treatment facility includes a photocatalytic net, and the photocatalytic net includes a net-laying frame and a net-shaped photocatalytic functional fiber fixed on the net-laying frame; the treatment facility also includes a biological rope and a submerged plant box attached to the photocatalytic net.

[0024] Specifically, the photocatalytic functional fiber includes a polypropylene filament as the base and a carbon-based metal semiconductor coated on the surface of the polypropylene filament.

[0025] Optionally, the laying area of the photocatalytic net accounts for 20% - 40% of the area of the water body to be treated; the laying position of the photocatalytic net is in the central area of the water body to be treated; the laying position of the photocatalytic net is 5 - 20 cm below the water surface; the photocatalytic net is fixed by underwater piles or underwater anchor blocks; the longitudinal axis of the photocatalytic net is parallel to the perennial dominant wind direction on the water surface.

[0026] Optionally, the treatment facility includes a deep aeration device, which is applicable to the water body to be treated with a water depth greater than 4m.

[0027] Furthermore, judging that the change trend of the key water quality purification factor deviates from the treatment target and adjusting the configuration strategy of the treatment facility includes:

[0028] Periodically evaluating the current water quality grade of the water body to be treated according to the detection data of the current key water quality purification factor;

[0029] Configuring corresponding-level maintenance measures for the treatment facility according to the current water quality grade;

[0030] Judging that the current water quality grade of the water body to be treated deviates from the preset water quality grade target, and adjusting the configuration content of the treatment facility and / or the content of the maintenance measures.

[0031] Optionally, the maintenance measures include at least one of the following:

[0032] Patrolling around the water body to be treated at a specified frequency;

[0033] Cleaning the surface garbage and floating objects of the water body to be treated at a specified frequency;

[0034] Cleaning the mesh surface biofilm of the photocatalytic net in the treatment facility at a specified frequency.

[0035] Compared with the prior art, the present application has the following advantages:

[0036] (1) The method of the present application uses a treatment facility including a photocatalytic net to be laid on the water surface for treatment. The photocatalytic net is made of a photocatalytic material, which can decompose organic substances in water without selectivity, promote the improvement of water transparency, increase the oxidation-reduction potential, improve the biodegradability of pollutants in water, and increase the dissolved oxygen in water;

[0037] (2) The method of the present application, before laying the treatment facility, through water quality investigation and environmental investigation, determines the key water quality purification factor, and conducts targeted design on the layout of the treatment facility, especially the photocatalytic net, to achieve the effects of short-term water quality improvement, medium-term ecological restoration, and long-term self-cleaning and healing;

[0038] (3) The method of the present application, after laying the treatment facility, also needs to manage and maintain the treatment facility according to the water quality grade, timely track the change trend of the key water quality purification factor, flexibly adjust the configuration content of the treatment facility and the content of the maintenance measures, and conduct refined and personalized treatment on the water body to be treated. Description of the Drawings

[0039] Figure 1 It is a top - view structural schematic diagram of the photocatalytic net adopted in this application.

[0040] Figure 2 It is the content and objective of the water quality investigation and environmental investigation of this application.

[0041] Figure 3 It is a distribution map of the treatment areas of the water source area adopting this application.

[0042] Figure 4 It is Figure 3 An enlarged view of the actual scene of the treatment area.

[0043] Figure 5 It is an aerial view of another water source area adopting this application.

[0044] Figure 6 It is Figure 5 The data record form of the water quality improvement project of the water source area indicated. Detailed implementation manners

[0045] The following further describes this application in detail in combination with the attached drawings and specific implementation manners.

[0046] The comprehensive water body treatment method based on photocatalysis of this application includes the following steps:

[0047] S1: Conduct a water quality investigation on the water body to be treated to determine the key water quality purification factors;

[0048] S2: Determine the configuration strategy of the treatment facilities according to the environmental conditions of the water body to be treated;

[0049] S3: After configuring the treatment facilities in the water body to be treated, monitor the key water quality purification factors; judge that the change trend of the key water quality purification factors deviates from the treatment target, and adjust the configuration strategy of the treatment facilities;

[0050] S4: Confirm that the water body to be treated reaches the treatment target, and withdraw the treatment facilities.

[0051] Specifically, the photocatalysis refers to the phenomenon that water molecules on the surface of a titanium dioxide electrode decompose into hydrogen and oxygen under ultraviolet light irradiation, which is also known as the photolysis phenomenon of water. The oxygen generated by this phenomenon can dissolve in water again to increase the dissolved oxygen in water. For water bodies rich in biomass, the increase in dissolved oxygen is beneficial to the healthy development of biomass. Moreover, the photocatalytic reaction generates hole-electron pairs, hydroxyl radicals and superoxide radicals with strong oxidizing properties. Based on this principle, the treatment of polluted water bodies is realized. In this application, a photocatalytic material containing titanium dioxide is made into a net shape and laid on the water surface to induce the occurrence of photocatalytic reactions through sunlight. The photocatalytic net of this application preferably includes a netting frame and a net-shaped photocatalytic functional fiber fixed on the netting frame. The photocatalytic functional fiber is based on polypropylene filaments, and a carbon-based metal semiconductor is coated on the surface of the polypropylene filaments. In a possible implementation, the photocatalytic functional fiber from the inside to the outside is successively a base layer, an intermediate protection layer, a sunlight / red light response layer, a quantum transition layer, and a quantum size effect photocatalytic layer. Since the quantum size effect photocatalytic layer uses doped graphene-based titanium dioxide, the photocatalytic net of this application is also called a graphene photocatalytic net.

[0052] Reference Figure 1 , the photocatalytic functional fiber is prepared into a standard unit 1. After every three standard units 1 are stitched, they are fixed on a standard netting frame 2. Multiple standard netting frames 2 can be combined and spliced to form a longitudinally long photocatalytic net. Each longitudinally long photocatalytic net can also be fixed to each other through connecting rods to form a sheet-like treatment facility on the water surface. Further, the treatment facility further includes a biological rope connected below the netting frame. The biological rope fixes an appropriate amount of anaerobic microorganisms to realize the treatment of the water quality in the underwater anaerobic and light-deficient environment. The treatment facility further includes a submerged plant box fixed on the outer periphery of the netting frame to further increase the dissolved oxygen in the water by adding submerged plants. In addition, the submerged plants also provide habitats and food for small animals in the water, which is beneficial to the ecological restoration of the water body. In order to enable the photocatalytic net to float in water, fixing measures need to be taken in water. A possible implementation includes fixing with underwater piles or underwater anchor blocks. In addition, floating rods 3 and weights should be provided on the netting frame to adjust the height of the photocatalytic net in water.

[0053] Further, the treatment facility can also be combined and applied with other ecological restoration or sewage treatment technologies through expansion, superposition, and recombination, such as ecological concrete technology, ecological dredging technology, magnetization induction technology, composite medium floating beds, etc.

[0054] The water body to be treated in this application mainly refers to a water body that meets the usage scenarios of the treatment facility. The treatment facility mainly composed of a photocatalytic net in this application is preferably applied in water bodies that meet at least one of the following conditions:

[0055] (1) The solar irradiance on the water surface is greater than 10,000 Lux, and more preferably, the solar irradiance is greater than 50,000 Lux. Generally speaking, there is less vegetation shading around the water body to be treated, which is conducive to sufficient sunlight exposure during the day. If the solar irradiance is insufficient during the day, or continuous photocatalytic reactions are required at night, solar lamps can be added to the water surface.

[0056] (2) The water flow velocity is not greater than 0.5 m / s, or the water flow velocity is not greater than 0.5 m / s for more than 4 days (or about 5 days). Accordingly, the method and treatment facilities of the present application are applicable to closed water bodies such as ponds, sewage ponds, oxidation ponds, lakes, water sources, wetlands, etc., and semi-closed water bodies such as slow-flowing rivers and dead-end ditches. Further, the above-mentioned closed water bodies and semi-closed water bodies should not be navigable to avoid mutual influence between passing ships and treatment facilities.

[0057] (3) The annual wind force on the water surface is in the range of level 1 to level 4, that is, it should mainly be light wind and gentle breeze. The coastal areas of our country are mostly affected by monsoons, and typhoons are frequent in summer. The water bodies near the sea affected by typhoons are greatly disturbed, which is not conducive to the laying and maintenance of the treatment facilities of the present application and is difficult to achieve the due treatment effect. Strong wind weather will also strengthen the water flow, and exceeding the above water flow velocity range is also not conducive to the treatment facilities of the present application to play a role.

[0058] (4) The air pollution degree in the upwind area of the water surface is below the preset value. If there is an industrial area in the upwind area of the water surface, the waste gas, waste water and waste residue generated by the industrial area should be controlled below the preset value to avoid secondary pollution to the water body to be treated or affecting the treatment effect of the treatment facilities.

[0059] (5) The water depth is greater than 0.5 m. According to the use conditions of the photocatalytic net, the photocatalytic net should be suspended 5 - 20 cm underwater. Insufficient water depth is difficult to provide enough buoyancy for the photocatalytic net. If the water depth exceeds 4 m, deep water pushing equipment should be set underwater to promote the exchange of deep water and shallow water.

[0060] Further, as Figure 2 shown in the ecological survey, it includes the work of counting the types and distribution states of various animals and plants in the water, including but not limited to the statistics of benthic animals, fish, submerged vegetation and plankton. The evaluation methods used include but not limited to using biodiversity index, Shannon index and ecological integrity index. Conducting ecological surveys aims to carry out targeted regulation of the water body ecology and reconstruct aquatic vegetation. The above-mentioned treatment facilities including photocatalytic nets are conducive to the ecological restoration of the water body to be treated to achieve self-purification cycle on the basis of establishing artificial floating wetlands and microbial reaction beds.

[0061] Figure 2The environmental investigation, including the comprehensive analysis of the hydrological conditions, environmental characteristics, water body shorelines, and topography and geology around the water body to be treated, provides a reference for the configuration of treatment facilities. On the other hand, the data provided by the environmental investigation can also be used for water conservancy allocation and control of hydrodynamic circulation, providing data support for the construction of ecological landscapes and ecological wetlands.

[0062] Ecological investigation and environmental investigation can also be assisted by using drone technology to obtain more complete and detailed monitoring data.

[0063] Those skilled in the art are aware that, in accordance with the environmental functions and protection objectives of surface water bodies in China, they are classified into 5 categories according to the level of function: Category I, mainly applicable to source water and national nature reserves; Category II, mainly applicable to the first-class protection area of centralized domestic drinking water surface water sources, habitats of rare aquatic organisms, spawning grounds of fish and shrimps, and feeding grounds for larvae, juveniles and fry; Category III, mainly applicable to the second-class protection area of centralized domestic drinking water surface water sources, wintering grounds of fish and shrimps, migration channels, fishery waters such as aquaculture areas of water plants, and swimming areas; Category IV, mainly applicable to general industrial water areas and entertainment water areas where the human body is not directly in contact; Category V, mainly applicable to agricultural water areas and water areas with general landscape requirements. In addition, waters evaluated as inferior to Category V and black and odorous basically have no use function. According to the above classification, the photocatalysis-based comprehensive water body treatment method of the present application is applicable to the treatment of water bodies with a water quality above Category III. The treatment objectives are determined according to the ecological conditions, environmental conditions and treatment duration of the water body. For example, a water body evaluated as Category III water quality can reach the Category II water quality standard after treatment, but may not necessarily reach the Category I water quality standard. The treatment objective of this Category III water quality water body should be set to reach the Category II water quality standard as much as possible; another example is that a water body evaluated as inferior to Category V, after comprehensively considering the ecological conditions, environmental conditions and treatment duration of the water body, it is evaluated that the water quality after treatment can reach Category IV. If the treatment duration is extended, it may also reach a level between Category III and Category IV. The treatment objective of this inferior Category V water body should be set to reach the Category IV water quality standard. Further, a short-term or medium- to long-term warning model can be established to predict the change trend during the treatment duration, providing more accurate data for adjusting the configuration strategy of the treatment facilities.

[0064] After the water body to be treated adopts the photocatalysis-based comprehensive water body treatment method of the present application, the physical changes include improving the water body transparency and increasing the dissolved oxygen in the water body; the chemical changes include decomposing the toxic and harmful organic substances in the water, and various chemical indicators decrease; the biological changes include activating the water body seed bank, adjusting the algal species structure, and ecological self-organization reconstruction occurs. On average, the apparent black and odor are eliminated in 7 days, the key indicators are significantly improved in 30 days, the COD removal rate reaches 43%, the ammonia nitrogen removal rate reaches 68%, the TP removal rate reaches 75%, and the DO increase rate reaches 200%.

[0065] The following is a further description of the comprehensive water treatment method based on photocatalysis of this application through examples.

[0066] The comprehensive water treatment method based on photocatalysis of this application was carried out in a drinking water source area of a city. Before the overall treatment of the entire water area, a treatment area was set up for experimental treatment. The treatment period spanned 455 days, and a total of 250 water quality indicators were detected. As Figure 3 shown, the net-laying area T1 was selected, with an area of about 5000 m 2 , a water depth of 6 - 7 m, the net-laying area T3, with an area of about 5000 m 2 , a water depth of 5 - 6 m, and the control area C1, with an area of about 5000 m 2 , a water depth of 6 - 7 m. The net-laying area of the net-laying area T1 accounted for 32% of the water area of the treatment area, and a biological rope with a hanging length of 2 m was suspended under the photocatalytic net; the net-laying area of the net-laying area T3 accounted for 63.3% of the water area of the treatment area, and the length of the biological rope was 4 m. The photocatalytic net was not laid in the control area C1.

[0067] The treatment time was divided into three stages:

[0068] The first stage lasted for 251 days, and the detection data of all water quality indicators were collected in a static flow state. There were 250 items of detection data; a total of 114 initial screening water quality indicators with detected values were screened out;

[0069] The second stage lasted for 152 days, and the detection data of the initial screening water quality indicators were collected respectively in a micro-flow state and a state of water body disturbance. 81 reference water quality indicators with significantly changed detected values were screened out;

[0070] In the third stage, through comprehensive analysis, 60 key water quality indicators were screened out from the reference water quality indicators as key water quality purification factors.

[0071] The 250 items of all water quality indicators include 109 items in the Surface Water Environment Quality Standard, 30 items in the Hygienic Standard for Drinking Water, 11 items in Drinking Natural Mineral Water and National Food Safety Standard Packaged Drinking Water, 26 biodiversity indicators, 64 non-national control trace organic pollutants, and 10 other indicators.

[0072] The 60 key water quality purification factors include 13 physical and chemical indicators, 10 algae, 3 algal toxins, 11 antibiotics, 10 endocrine disruptors, 4 zooplankton, 4 benthic animals, 2 higher aquatic plants, and 3 fish.

[0073] The geographical location of this water source is affected by the East Asian monsoon. During the first stage, the southeast wind prevails in this water source area, and the wind force is mainly at level 1-4; during the second stage, the northeast wind prevails, and the wind force is mainly at level 1-4. Therefore, the wind force throughout the year in this water source area is mainly light wind and gentle breeze, which is suitable for adopting the method of this application to treat the water quality of the entire water area. Reference Figure 3 and Figure 4 , due to the periodic change of the wind direction of the monsoon, it is not suitable for the longitudinal axis of the photocatalytic net to be adjusted periodically following the wind direction. After comprehensive consideration, the longitudinal axis of the photocatalytic net is set to intersect with the prevailing wind direction at an acute angle to avoid the situation of increasing the up and down floating of the photocatalytic net in the water when intersecting vertically.

[0074] In this embodiment, the experimental data in the treatment area show that the water transparency has increased by 2.3 times, the total suspended solids have decreased by 97%, and the algal growth rate in the water body has decreased by 30-60%, indicating that the aquatic environment is developing in a positive direction. The harmful trace organic substances in the water body have been significantly reduced, the removal rate of endocrine disruptors has increased by 27%, and the removal rate of antibiotics has increased by 15%, effectively inhibiting the production of algal toxins and improving the water environment. The plant coverage rate has reached 3 times that before treatment, the average growth height has reached 5 times that before treatment, the biomass of radix auricularia has increased by 169 times, the density has increased by 488 times, the biodiversity has been significantly improved, the water ecosystem has continued to develop healthily, and the water purification efficiency and effect have been improved.

[0075] In the subsequent stage of treating the entire water area, 60 key water quality purification factors selected in the treatment area will be used as evaluation indicators to guide the configuration and management methods of the treatment facilities.

[0076] Implementing the comprehensive water body treatment method based on photocatalysis of this application in the entire water area of another urban drinking water source, the process is as follows:

[0077] The water source of this embodiment is located in the eastern coastal area of our country. The maximum water level area is about 24,000 ㎡, the daily water level water surface area is about 15,000 ㎡, and the water depth is nearly 20 m. During the flood season, the water quality is relatively good, and each index is better than Class III of surface water. During the dry season, due to less rainfall, large evaporation, and insufficient water power, the water quality deteriorates (refer to Table 1), and it is difficult for the water body to reach the drinking water raw water standard. Therefore, in order to keep the reservoir water quality stable at the drinking water source index (Class II surface water), it is necessary to treat it.

[0078] Table 1 Background data

[0079]

[0080] Before laying the photocatalytic net for the entire water area, a treatment area is set to screen key water quality purification factors, and a configuration strategy for treatment facilities is formulated by comprehensively considering the ecological conditions, environmental conditions and treatment objectives of this water source. Reference Figure 5The water source was installed with 1,200 photocatalytic nets, totaling 4,860 square meters, covering approximately 32% of the daily water level. 180 semi-submerged plant floating frames, totaling 540 square meters, were installed. 4,560 bio-rope ropes, totaling 11,400 meters, and 4,900 PFU balls were installed. Based on the physical and chemical properties of the photocatalytic nets, the netting area generally accounts for 20-30% of the water area to be treated, and can be increased to 40% if necessary. Specifically, if the COD value falls within the Class V range, the netting area can be up to 40%, while if the COD value falls within Class II, the minimum coverage area can be 20%.

[0081] As can be seen from the figure, the photocatalytic network of the water source is laid in the central area of the water area. The longitudinal axes of each photocatalytic network are parallel to each other and try to be parallel to the dominant wind direction of the water surface of the water source all year round.

[0082] After the photocatalytic network is laid, it is necessary to periodically evaluate the current water quality level of the water source based on the detection data of the current key water quality purification factors; the photocatalytic network is graded and maintained according to the current water quality level. The correspondence between water quality level and maintenance measures is shown in Table 2, which mainly involves stipulating the frequency of inspections around the water body to be treated, the frequency of cleaning the surface garbage and floating objects of the water body to be treated, and the frequency of cleaning the biofilm on the surface of the photocatalytic network in the water body to be treated.

[0083] Furthermore, the cleaning and maintenance methods of the photocatalytic net should follow the following rules: (1) Use a plastic container to clean the net surface, and gently rinse it on the water surface to remove debris and biofilm from the net surface to achieve the cleaning effect. (2) When the water depth is sufficient, turn the net surface over to achieve the cleaning effect. (3) It is necessary to check that the photocatalytic net of each unit is properly fixed and there is no detachment or damage. (4) If the net surface is observed to be yellow after a layer of aerobic biofilm is attached, it is normal and can be left uncleaned for the time being. If the biofilm on the net surface is too thick and the bottom biofilm is anaerobic and black, it needs to be cleaned. (5) It is forbidden to use a high-pressure water gun to spray the net surface.

[0084] refer to Figure 6 As shown in the charts, the ammonia nitrogen content, total phosphorus content, and COD value of the water source are generally on a downward trend, and the latest data test results have reached the Class II surface water standard. Statistics on algal diversity revealed that algal density in the water remains at a relatively low level, with the overall algal biomass reduced to one-third of its original level, effectively avoiding the risk of algal blooms. Furthermore, the algal species composition is no longer dominated by diatoms, and the algal structure is gradually becoming more balanced.

[0085] Table 2 Management and Maintenance Control Table

[0086]

[0087]

[0088] In summary, the comprehensive water body treatment method based on photocatalysis in this application includes: conducting a water quality investigation on the water body to be treated to determine key water quality purification factors; determining the configuration strategy of the treatment facilities according to the environmental conditions of the water body to be treated; monitoring the key water quality purification factors after configuring the treatment facilities in the water body to be treated; judging that the change trend of the key water quality purification factors deviates from the treatment target, and adjusting the configuration strategy of the treatment facilities; confirming that the water body to be treated reaches the treatment target, and withdrawing the treatment facilities. Before laying the treatment facilities, the method of this application conducts a water quality investigation and an environmental investigation to determine the key water quality purification factors, and conducts a targeted design on the layout of the treatment facilities, especially the photocatalytic network, to achieve the effects of short-term water quality improvement, medium-term ecological restoration, and long-term self-cleaning and healing.

[0089] The above embodiments are preferred embodiments of this application, but are not limited to only the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of this application shall be equivalent replacement methods and are all included in the protection scope of this application.

Claims

1. A comprehensive water treatment method based on photocatalysis, characterized in that, It includes the following steps: Conduct a water quality survey on the water body to be treated to determine key water quality purification factors: Set up a treatment area in the water body to be treated; During the treatment time, collect the detection data of the water quality indicators in the treatment area under different water flow states respectively; Screen out the key research indicators from all the water quality indicators as the key water quality purification factors; The treatment area includes a net-laying area where a photocatalytic net is laid and a control area; During the treatment time, collect the detection data of the water quality indicators under the following conditions in sequence: Collect the detection data of all water quality indicators in the static flow state, and screen out the initially screened water quality indicators with detected values; Collect the detection data of the initially screened water quality indicators under the micro-flow state and the water body disturbance state respectively, and screen out the reference water quality indicators with significant changes in the detected values; Screen out the key water quality indicators from the reference water quality indicators as the key water quality purification factors; Determine the configuration strategy of the treatment facilities according to the environmental conditions of the water body to be treated; After configuring the treatment facilities in the water body to be treated, monitor the key water quality purification factors; Judge that the change trend of the key water quality purification factors deviates from the treatment target, and adjust the configuration strategy of the treatment facilities; Confirm that the water body to be treated reaches the treatment target, and withdraw the treatment facilities.

2. The method according to claim 1, wherein The water body to be treated meets at least one of the following conditions: The surface solar irradiance is greater than 10000 Lux; The water flow velocity is not greater than 0.5 m / s; The water flow velocity is not greater than 0.5 m / s for more than 4 days; The water depth is greater than 0.5 m; The air pollution degree in the upwind area of the water surface is below the preset value; The annual wind force on the water surface is level 1 - 4; The water body is a non-navigable closed water body or semi-closed water body.

3. The method according to claim 1, wherein The number of the key water quality indicators is not less than 50% of the number of the reference water quality indicators.

4. The method according to claim 1, wherein The treatment facilities include a photocatalytic net, and the photocatalytic net includes a net-laying frame and a net-shaped photocatalytic functional fiber fixed on the net-laying frame; The treatment facilities also include biological ropes and submerged plant boxes attached to the photocatalytic net.

5. The method according to claim 4, wherein The photocatalytic functional fiber includes a polypropylene filament as the base and a carbon-based metal semiconductor coated on the surface of the polypropylene filament.

6. The method according to claim 4, wherein The laying area of the photocatalytic net accounts for 20 - 40% of the area of the water body to be treated; The laying position of the photocatalytic net is in the central area of the water body to be treated; The laying position of the photocatalytic net is 5 - 20 cm below the water surface; The photocatalytic net is fixed by underwater piles or underwater anchor blocks; The longitudinal axis of the photocatalytic net is parallel to the perennial dominant wind direction of the water surface.

7. The method according to claim 4, wherein The treatment facilities include deep-pushing flow equipment, which is applicable to the water body to be treated with a water depth greater than 4 m.

8. The method according to claim 1, wherein The judgment that the change trend of the key water quality purification factors deviates from the treatment target and the adjustment of the configuration strategy of the treatment facilities includes: Periodically evaluate the current water quality grade of the water body to be treated according to the detection data of the current key water quality purification factors; Configure the corresponding grade of maintenance measures for the treatment facilities according to the current water quality grade; Judge that the current water quality grade of the water body to be treated deviates from the preset water quality grade target, and adjust the configuration content of the treatment facilities and / or adjust the content of the maintenance measures.

9. The method according to claim 8, wherein The maintenance measures include at least one of the following: Conduct inspections around the water body to be treated at specified frequencies; Clean the surface garbage and floating objects on the water body to be treated at specified frequencies; Clean the biofilm on the surface of the photocatalytic net in the treatment facility at specified frequencies.

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