In-situ treatment system for enhanced purification of overflow pollution of river inlet discharge port

Abstract

The invention discloses an in-situ treatment system for enhanced purification of overflow pollution of a river inlet discharge port, and belongs to the technical field of water environment treatment. The in-situ treatment system comprises a magnetic flocculation precipitation unit and an ecological slope protection purification unit. Overflow sewage of a river channel discharge port is firstly intercepted to the magnetic flocculation sedimentation unit by the sewage lifting pump, and in the process, the overflow sewage is firstly preliminarily mixed with a composite flocculant polyferric silicate sulfate in the sewage inlet pipe, and then enters the magnetic seed mixing reaction tank to be further fully and uniformly stirred and mixed with magnetic seeds. According to the invention, an integrated overflow sewage pretreatment device and an ecological slope protection deep purification filter tank are established near a river inlet discharge port side slope by utilizing a slope top and a large-area river side slope. And under the conditions of low investment and low operation cost, the problem that the river inlet discharge port overflow pollution treatment generally lacks a site is solved according to local conditions.

Description

1. Technical Field

[0001] The invention belongs to the technical field of water environment treatment, and in particular relates to an in-situ treatment system for enhanced purification of overflow pollution from a river outlet. 2. Background Technology

[0002] With the accelerated advancement of urbanization, the built-up area has continued to expand, resulting in a large increase in impervious areas. Under the same rainfall conditions, the runoff coefficient increases, the flood peak is advanced, and the flood volume increases. This further exacerbates the discharge of overflow pollution from the drainage network into the water body on rainy days, including overflow pollution from the combined system on rainy days and initial rainwater discharge from the diversion system, which is the main reason for the frequent occurrence of black and smelly phenomena on rainy days. Overflow pollution mainly includes suspended solids (SS), chemical oxygen demand (COD), heavy metals, eutrophic substances (such as nitrogen and phosphorus), pathogenic bacteria, humus and new pollutants. These pollutants come from a wide range of sources, including atmospheric pollutants brought by rainfall, pollutants washed by surface runoff, pipe sediments and domestic sewage. Studies have shown that pipe sediments discharged from overflows contribute 30% to 80% of the water pollution load in rainfall events. In addition, the quality of overflow water on rainy days fluctuates greatly, and the concentrations of SS and COD can vary from tens to thousands of mg / L. Overflow pollution occurs on rainy days. Its discharge is intermittent and sudden, and the instantaneous pollution load is large. Due to the complexity and diversity of overflow water quality, this poses a huge challenge to urban water environment management.

[0003] The manifestation of overflow pollution at river outlets is in the water, the root cause is on the shore, the key is the pipe network, and the core is the outlet. At present, the control measures for overflow pollution at river outlets mainly include source control, pipe network transformation and terminal treatment. Whether it is strengthening green space construction, promoting rainwater gardens, advocating rainwater collection and utilization from the source to reduce rainwater runoff, or taking technical means such as pipe network diversion transformation and setting up flood storage areas to reduce pollution load, it cannot ensure that overflow pollution is avoided when rainfall and water quality fluctuate greatly. Therefore, terminal treatment has attracted much attention as the most effective measure to control overflow pollution. Traditional terminal treatment methods include activated sludge method, artificial wetland, screen treatment, vortex water diversion tank, cyclone separator, coagulation-flocculation and chemical agent method, but these methods have obvious shortcomings in treating rainy overflow pollution. First, biological methods (such as activated sludge method and artificial wetland) are more sensitive to fluctuations in water quality and quantity, and it is difficult to cope with the changes in water quality caused by rainy overflow, and the treatment effect is unstable. Secondly, although physical methods (such as screen treatment, vortex water separation tank and cyclone separator) have a fast treatment speed, the treatment effect is poor and it is difficult to completely remove overflow pollutants. Although chemical methods (such as coagulation-flocculation and chemical agent methods) can reduce part of the pollution load, there is a problem that soluble pollutants such as COD and ammonia nitrogen cannot be removed, and it is easy to affect the water ecology. In addition, traditional treatment methods require a lot of land resources and high operating costs, and have a great impact on water quality changes and climate, and the treatment cycle is long. Especially for river outlets near rivers, due to geographical restrictions, it is difficult to implement traditional centralized treatment methods, resulting in poor treatment effects.

[0004] Therefore, there is an urgent need for a low-cost, high-efficiency overflow pollution treatment technology. This system should be able to treat sewage on-site near the overflow outlet, reduce dependence on the site, and effectively improve the purification effect of the water body, improve the quality of the urban water environment, and achieve the goal of long-term governance. III. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides an in-situ treatment system for enhanced purification of overflow pollution from river outlets. The system can be set up near the slope of the river outlet, and use the top of the slope and the large-area river slope to establish an integrated overflow sewage pretreatment device and an ecological slope protection deep purification filter. With low investment and low operating costs, the problem of the general lack of space in the treatment of overflow pollution from river outlets is solved in a localized manner. At the same time, the invention can play a lateral treatment role on river water, and has a significant effect on improving and long-term maintaining the water quality of polluted rivers.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] An in-situ treatment system for enhanced purification of overflow pollution at a river outlet comprises a magnetic flocculation sedimentation unit; the magnetic flocculation sedimentation unit comprises a sewage lifting pump, a sewage inlet pipe, a magnetic seed mixing reaction tank, a flocculant dosing device, a magnetic separator and a magnetic flocculation reaction tank.

[0008] As a further improvement of the technical solution, the flocculant dosing device stores the composite flocculant polysilicate ferric sulfate, and the flocculant is added to the sewage inlet pipe through the flocculant dosing point. The flocculant dosing point is provided with a metering pump to control the content of the composite flocculant polysilicate ferric sulfate in the sewage to be 3-6 mg / L; the magnetic separator adds magnetic seeds to the magnetic seed mixing reaction tank through the magnetic seed dosing point, and the magnetic seed dosing amount in the magnetic seed mixing reaction tank is 100-200 mg / L. The sewage lifted by the sewage lifting pump is preliminarily mixed with the composite flocculant polysilicate ferric sulfate in the sewage inlet pipe, and then enters the magnetic seed mixing reaction tank to further stir and mix with the magnetic seeds, and finally discharged into the magnetic flocculation reaction tank, and mud and water separation is carried out under the condition of a magnetic field strength of 80-100 mT.

[0009] As a further improvement of the technical solution, the magnetic mud produced at the bottom of the magnetic flocculation reaction tank is returned to the magnetic separator through the mud discharge pipe for deflocculation and recovery treatment.

[0010] As a further improvement of the technical solution, it also includes an ecological slope protection purification unit, which utilizes the physical, chemical and biological synergistic effects of adsorption materials, microorganisms, media and plants to deeply treat soluble pollutants such as COD, ammonia nitrogen, total phosphorus and other soluble pollutants remaining in the sewage after magnetic flocculation precipitation treatment, so as to achieve the goal of removing pollutants in the sewage and further improve the water purification effect; the ecological slope protection purification unit includes a water distribution main channel inlet pipe, a water distribution main channel and a microbial automatic activation inoculation device located on the top of the slope, a first-level slope protection biological filter located on the slope bank, a second-level slope protection biological filter and a third-level slope protection biological filter.

[0011] As a further improvement of the technical solution, the water inlet pipe of the water distribution main canal is arranged above the water distribution main canal, so that the water flow after magnetic flocculation treatment enters the water distribution main canal in a waterfall manner; the first-level slope protection biofilter, the second-level slope protection biofilter and the third-level slope protection biofilter are successively arranged in a stepped manner on the high platform, the middle platform and the low platform of the slope bank, and the height difference between adjacent platforms is 0.5 to 1m; the water distribution main canal-various levels of slope protection biofilter-river channel are arranged from top to bottom into a multi-level stepped combination system using the slope, so that water flow is transferred between the treatment facilities at each level in a waterfall manner, and the impact of the water flow and the contact of the gas-liquid interface are used to increase the oxygen content in the water body, so as to solve the problem of low dissolved oxygen content in overflow sewage and further improve the removal efficiency of pollutants.

[0012] As a further improvement of the technical solution, the slope protection biological filter is provided with a gravel filling layer, a ceramsite filling layer and wetland plants from bottom to top; the gravel particle size in the gravel filling layer is 20-40mm, and the filling thickness is 0.2-0.3m; the ceramsite particle size in the ceramsite filling layer is 10-30mm, and the filling thickness is 0.1-0.2m; the wetland plants planted on the filling layer should be suitable for the landscape, and should achieve the dual effects of purifying water quality and aesthetics; the gravel filling layer, as a bottom layer, plays a role of physical support and stability in the filter; the ceramsite filling layer is located above the gravel filling layer, and its structure is porous and has a large surface area, which is conducive to biological attachment and microbial degradation, and the pore structure in the ceramsite filling layer helps to increase the transfer of oxygen and gas exchange between the water body and the atmosphere, thereby promoting the growth and metabolism of organisms in the filter.

[0013] As a further improvement of the technical solution, a permeable reaction wall is provided on the side of the slope protection biological filter tank near the river channel. The outer layer of the permeable reaction wall is composed of a grid frame, and the interior is filled with a high-efficiency adsorption and purification functional material; the high-efficiency adsorption and purification functional material is composed of iron-modified biochar, clay minerals, and adhesive mixed granulation, and the distribution ratio of each component is: iron-modified biochar 50% to 60%, clay minerals 20% to 30%, and adhesives 10% to 20%; the high-efficiency adsorption and purification functional material can effectively remove pollutants in the water through adsorption, biodegradation and physical interception, thereby improving the purification effect of the slope protection biological filter tank; the slope protection biological filters at each level are filled with The particle size of the high-efficiency adsorption and purification functional material decreases step by step along the water flow direction, specifically: the particle size of the high-efficiency adsorption and purification functional material in the first-level slope protection biological filter is 15-20 mm, the particle size of the high-efficiency adsorption and purification functional material in the second-level slope protection biological filter is 8-15 mm, and the particle size of the high-efficiency adsorption and purification functional material in the third-level slope protection biological filter is 3-8 mm; by gradually reducing the particle size of the filler particles along the water flow direction, the adsorption efficiency of the filler can be improved, the biological attachment points can be increased, the water flow distribution can be optimized and blockage can be avoided; the filling thickness of the high-efficiency adsorption and purification functional material is 0.15-0.2 m, and the filling height is 0.6-0.8 m.

[0014] As a further improvement of the technical solution, the microbial automatic activation inoculation device amplifies the local beneficial microorganisms in the system through the circulating water inlet and circulating water outlet arranged in the water distribution main channel, realizes the in-situ degradation of water pollutants and the synchronous reduction of bottom mud, and improves the efficiency of microbial degradation and removal of pollutants in the water body; the microbial automatic activation inoculation device is composed of a box with anoxic and aerobic sections; the anoxic section is operated as an open biological filter bed, and specific strengthening reagents of nitrifying-denitrifying bacteria and polyphosphate bacteria are added; an aerobic section is built after the anoxic section to promote the conversion of ammonia nitrogen into nitrate and promote the absorption of phosphorus, and ester fillers are used as filling materials in the aerobic stage; the polyphosphate bacteria that are strengthened and activated in the anoxic section take phosphorus, so that microorganisms with phosphorus accumulation are released into the water body and participate in the metabolic process of the microorganisms; in addition, an aerobic stage is established to improve the utilization rate of natural dissolved organic matter (DOM); a self-priming pump is provided to balance the water inlet, water outlet and internal circulation of the microbial enhancement technology.

[0015] As a further improvement of the technical solution, the hydraulic retention time of the magnetic flocculation sedimentation unit is 15 to 20 minutes; the hydraulic retention time of the ecological slope protection purification unit is 8 to 12 hours.

[0016] As a further improvement of the technical solution, the magnetic flocculation sedimentation unit and the ecological slope protection purification unit are arranged in sequence in the direction of water flow to form a complete system, and the setting heights are successively reduced, which can achieve the effect of automated management and reduce power loss.

[0017] An in-situ treatment system for enhanced purification of overflow pollution from river outlets, the specific steps are:

[0018] S1. The overflow sewage lifted by the sewage lifting pump is mixed with the composite flocculant polysilicate ferric sulfate while passing through the sewage inlet pipe, and is initially mixed under the turbulent conditions provided by the sewage's own hydrodynamics; then it enters the magnetic seed mixing reaction tank, and gradually forms dense flocs wrapped with magnetic media under the action of the stirrer; the flocs are pushed to the magnetic flocculation reaction tank with the water flow. During this process, the sewage is discharged from the magnetic flocculation inlet pipe located in the center of the reaction tank into the reactor from top to bottom. An umbrella-shaped baffle is provided under the water inlet to make the sewage evenly distributed in the tank, and then slowly rises along the entire cross-section of the tank, and generates a vortex. The magnetic flocs with magnetic cores settle to the conical sludge hopper at the bottom of the tank under the action of gravity and 80-100mT magnetic field force, and the supernatant is discharged from the overflow weir at the orifice at the top of the tank to the inlet pipe of the water distribution main canal.

[0019] S2. The water treated by magnetic flocculation flows into the water distribution main channel at the top of the slope in the form of a waterfall through the water distribution main channel inlet pipe. After being collected in the water distribution main channel, it is distributed to the first-level slope protection biological filter on the slope bank by the water distribution branch pipe. After being treated by the permeable reaction wall on one side of the filter, the water falls from the overflow plate below to the second-level slope protection biological filter, and then falls from the second-level slope protection biological filter to the third-level slope protection biological filter along the same path, until it falls from the third-level slope protection biological filter into the river channel.

[0020] S3. When there is no overflow sewage, turn off the sewage lifting pump, turn on the river water inlet pump, and pump the river water to the main water distribution channel on the top of the slope through the river side inlet pipe. While maintaining the activity of microorganisms in the biological filter and artificial wetland plants, the water quality of the river water is further improved; when it rains next time, turn off the river water inlet pump and repeat the steps of overflow sewage treatment.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) The present invention aims at the problem of managing overflow pollution at river outlets. The magnetic flocculation sedimentation unit, the ecological slope protection purification unit and the microbial automatic activation inoculation device are used comprehensively at the river outlet. The system realizes multiple physical, chemical and biological purification effects, and can more comprehensively and thoroughly treat various pollutants in the overflow sewage. In particular, the ecological slope protection purification unit combines a multi-stage stepped biological filter and a permeable reaction wall constructed of high-efficiency adsorption and purification functional materials, and integrates a microbial automatic activation inoculation system to form an organic combination. The coupling unit not only has the functions of contact oxidation and high-efficiency adsorption of pollutants, but also can automatically add high-efficiency microorganisms / enzyme preparations or other substances that improve the living environment of microorganisms through the indigenous microbial enzyme activation equipment, thereby enhancing the growth and metabolic capacity of indigenous microorganisms, and quickly decomposing and removing river pollutants. It has good practical value and high novelty.

[0023] (2) In view of the characteristics of overflow pollution at the outlet, the magnetic flocculation technology with high treatment efficiency and small footprint is selected as the front-end pretreatment unit of overflow pollution at the end of the drainage system, which effectively removes insoluble solid suspended pollutants and reduces pollution load. In the back section, a large area of ​​vacant riverbank is used to construct a multi-level stepped ecological slope protection purification unit, which further enhances the purification effect of insoluble pollutants and makes full use of the power of water flow and the contact of gas-liquid interface, increases the oxygen content in the water body, and improves the removal efficiency of pollutants. Therefore, this technology solves the problem of small available area at the river outlet and difficult layout of engineering facilities. It is also highly integrated and automated, easy to maintain and manage, has good treatment effect, can be recycled, and has a high value for promotion and use.

[0024] (3) This technology can not only quickly purify the overflow sewage into the river outlet, but also open the river water inlet pump during non-rainfall periods and when there is no overflow pollution, and pump the river water to the main water distribution channel on the top of the slope through the river side inlet pipe, while maintaining the activity of microorganisms in the biological filter and artificial wetland plants, further improving the water quality of the river. Therefore, this technology has a significant effect on improving and long-term maintenance of the water quality of polluted rivers.

[0025] (4) By introducing microorganisms and plants and creating a green landscape with ecological slope protection, the system enhances biodiversity, protects the habitats of native species, and enables the river ecosystem to be as close to its natural state as possible. This not only enhances the stability and biodiversity of the ecosystem, but also promotes the sustainable development of the ecological environment around the river. IV. Description of the drawings

[0026] Figure 1 It is a structural schematic diagram of an in-situ treatment system for enhanced purification of overflow pollution at river outlets;

[0027] Figure 2 This is a top view of the ecological slope protection and purification unit;

[0028] In the figure: 1. Magnetic flocculation sedimentation unit; 1.1. Sewage lifting pump; 1.2. Sewage inlet pipe; 1.3. Magnetic seed mixing reaction tank; 1.4. Mixer; 1.5. Flocculant dosing device; 1.6. Metering pump; 1.7. Flocculant dosing point; 1.8. Magnetic separator; 1.9. Magnetic seed dosing point; 1.10. Magnetic flocculation reaction tank; 1.11. Magnetic flocculation inlet pipe; 1.12. Orifice overflow weir; 1.13. Mud discharge pipe;

[0029] 2. Ecological slope protection and purification unit; 2.1. Water distribution main channel inlet pipe; 2.2. Water distribution main channel; 2.3. Primary slope protection biofilter; 2.4. Secondary slope protection biofilter; 2.5. Thirdary slope protection biofilter; 2.6. Microbial automatic activation inoculation device; 2.7. Permeable reaction wall; 2.8. Gravel filler layer; 2.9. Ceramsite filler layer; 2.10. Wetland plants; 2.11. Overflow plate; 2.12. Circulation outlet; 2.13. Circulation inlet; 2.14. Water distribution branch pipe; 2.15. River water side inlet pipe; 2.16. River water inlet pump; 2.17. Hydrophilic steps;

[0030] 3. River channel. V. Specific implementation methods

[0031] The exemplary embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. Although these examples are fully described, it should be understood that there are other feasible embodiments and various changes can be made without departing from the core spirit and scope of the present invention. The detailed description of the embodiments does not limit the scope of the present invention, but is only for the purpose of illustrating the best way to perform the present invention so that the technician can implement it. Therefore, the scope of the present invention is limited only by the claims.

[0032] Example 1

[0033] The in-situ treatment system of this embodiment for enhanced purification of overflow pollution into the river outlet is as follows: Figure 1 As shown, it includes a magnetic flocculation sedimentation unit 1; the magnetic flocculation sedimentation unit 1 is composed of a sewage lifting pump 1.1, a sewage inlet pipe 1.2, a flocculant dosing device 1.5 arranged on the sewage inlet pipe 1.2, a magnetic seed mixing reaction tank 1.3, a magnetic separator 1.8 arranged on the magnetic seed mixing reaction tank 1.3, and a magnetic flocculation reaction tank 1.10 in the water flow direction; the flocculant dosing device 1.5 stores a composite flocculant polyferric silicate sulfate, and the flocculant is added to the sewage inlet pipe 1.2 through a flocculant dosing point 1.7, and a metering pump 1.6 is arranged on the flocculant dosing point 1.7 to control The content of composite flocculant polyferric silicate sulfate in sewage is 3-6 mg / L; the magnetic separator 1.8 adds magnetic seeds into the magnetic seed mixing reaction tank 1.3 through the magnetic seed adding point 1.9, and the magnetic seed adding amount in the magnetic seed mixing reaction tank 1.3 is 100-200 mg / L; the magnetic seed mixing reaction tank 1.3 can be set as a rectangular cylinder, and a stirrer 1.4 is arranged in the tank body to fully stir and mix the sewage and the magnetic seeds; the magnetic flocculation reaction tank 1.10 can be set as a cylindrical cylinder, a mud discharge pipe 1.13 is arranged at the bottom of the tank, a magnetic flocculation water inlet pipe is arranged in the center of the tank, and an orifice overflow weir 1.12 is arranged on the top.

[0034] The in-situ treatment system for enhanced purification of overflow pollution from river outlets of this embodiment selects magnetic flocculation technology with high treatment efficiency and small footprint as the front-end pretreatment unit for overflow pollution at the end of the drainage system in view of the characteristics of large pollution load and high suspended solid concentration of overflow sewage from the outlet, which can effectively remove insoluble solid suspended pollutants and reduce pollution load; specifically, the sewage lifted by the sewage lifting pump 1.1 is preliminarily mixed with the composite flocculant polyferric silicate sulfate in the sewage inlet pipe 1.2, and then enters the magnetic seed mixing reaction tank 1.3 to further stir and mix with the magnetic seed, and finally discharged into the magnetic flocculation reaction tank 1.10, and mud and water separation is carried out under the condition of a magnetic field strength of 80 to 100 mT. The magnetic mud generated at the bottom of the magnetic flocculation reaction tank 1.10 is refluxed to the magnetic separator 1.8 through the mud discharge pipe 1.13 for deflocculation and recovery treatment, and the supernatant is discharged from the orifice overflow weir 1.12 at the top of the tank.

[0035] Example 2

[0036] The in-situ treatment system for enhanced purification of overflow pollution from river outlets of this embodiment is further provided with an ecological slope protection purification unit 2 in order to further treat the sewage after mud-water separation in the magnetic flocculation reaction tank 1.10. The unit utilizes the physical, chemical and biological synergistic effects of adsorption materials, microorganisms, media and plants to deeply treat soluble pollutants such as COD, ammonia nitrogen and total phosphorus remaining in the sewage after magnetic flocculation precipitation treatment, thereby achieving the goal of removing pollutants in the sewage and further improving the water purification effect. The ecological slope protection purification unit 2 includes a water distribution main channel inlet pipe 2.1, a water distribution main channel 2.2 and a microbial automatic activation inoculation device 2.6 arranged on the top of the slope, a first-level slope protection biofilter 2.3, a second-level slope protection biofilter 2.4 and a third-level slope protection biofilter 2.5 arranged on the slope bank.

[0037] As a further improvement of the technical solution, the water inlet pipe 2.1 of the water distribution main channel is arranged above the water distribution main channel 2.2, so that the water flow after magnetic flocculation treatment enters the water distribution main channel 2.2 in a waterfall manner; the first-level slope protection biofilter 2.3, the second-level slope protection biofilter 2.4 and the third-level slope protection biofilter 2.5 are arranged in a stepped manner on the high platform, the middle platform and the low platform of the slope bank, and the height difference between adjacent platforms is 0.5 to 1m; the water distribution main channel-the various levels of slope protection biofilters-the river channel are arranged from top to bottom into a multi-level stepped combination system using the slope, so that water flow is transferred between the treatment facilities at each level in a waterfall manner, and the impact of the water flow and the contact of the gas-liquid interface are used to increase the oxygen content in the water body, so as to solve the problem of low dissolved oxygen content in overflow sewage and further improve the removal efficiency of pollutants.

[0038] As a further improvement of the technical solution, the slope protection biofilter is provided with a gravel filling layer 2.8, a ceramsite filling layer 2.9 and wetland plants 2.10 from bottom to top; the gravel particle size in the gravel filling layer 2.8 is 20-40 mm, and the filling thickness is 0.2-0.3 m; the ceramsite particle size in the ceramsite filling layer 2.9 is 10-30 mm, and the filling thickness is 0.1-0.2 m; the wetland plants 2.10 planted on the filling layer should be suitable for the landscape and should achieve water purification. The filter tank has the dual effects of quality and beauty, specifically Phragmites australis, Canna, Calamus, and Iris; the gravel filler layer 2.8, as the bottom layer, plays a role of physical support and stability in the filter tank; the ceramsite filler layer 2.9 is located above the gravel filler layer 2.8, and its porous structure and large surface area are conducive to biological attachment and microbial degradation, and the pore structure in the ceramsite filler layer 2.9 helps to increase the transfer of oxygen and the gas exchange between the water body and the atmosphere, and promotes the growth and metabolism of organisms in the filter tank.

[0039] As a further improvement of the technical solution, a permeable reaction wall 2.7 is provided on the side of the slope protection biological filter tank close to the river channel. The outer layer of the permeable reaction wall 2.7 is composed of a grid frame, and the interior is filled with a high-efficiency adsorption and purification functional material; the high-efficiency adsorption and purification functional material is composed of iron-modified biochar, clay minerals, and adhesives mixed and granulated, and the distribution ratio of each component is: iron-modified biochar 50%-60%, clay minerals 20%-30%, and adhesives 10%-20%; the preparation method of the iron-modified biochar is: after mixing the garden waste biomass and the iron salt solution, a hydrothermal carbonization reaction is carried out in a hydrothermal reactor, and then the obtained hydrothermal carbon is dried, and then a high-temperature heat treatment is carried out in a tubular furnace, and in an inert atmosphere, the iron ions are reduced to form nano-iron particles by reduction, and the nano-iron particles are combined with the biochar; the high-efficiency adsorption and purification functional material is adsorbed, generated, and purified by adsorption. The effects of biodegradation and physical interception can effectively remove pollutants in the water, thereby improving the purification effect of the slope protection biological filter; the particle size of the high-efficiency adsorption and purification functional materials filled in the slope protection biological filters at each level is gradually reduced along the water flow direction, specifically: the particle size of the high-efficiency adsorption and purification functional materials in the first-level slope protection biological filter 2.3 is 15-20mm, the particle size of the high-efficiency adsorption and purification functional materials in the second-level slope protection biological filter 2.4 is 8-15mm, and the particle size of the high-efficiency adsorption and purification functional materials in the third-level slope protection biological filter 2.5 is 3-8mm; by gradually reducing the particle size of the filler particles along the water flow direction, the adsorption efficiency of the filler can be improved, the biological attachment points can be increased, the water flow distribution can be optimized and blockage can be avoided; the filling thickness of the high-efficiency adsorption and purification functional materials is 0.15-0.2m, and the filling height is 0.6-0.8m.

[0040] As a further improvement of the technical solution, the microbial automatic activation inoculation device 2.6 is used to amplify the local beneficial microorganisms in the system through the circulating water inlet 2.14 and the circulating water outlet 2.13 provided in the water distribution main channel 2.2, so as to achieve in-situ degradation of water pollutants and synchronous reduction of bottom sediments, and improve the efficiency of microbial degradation and removal of pollutants in the water body; the microbial automatic activation inoculation device 2.6 is composed of a box provided with anoxic and aerobic sections; wherein the anoxic section is operated as an open biological filter bed, and specific strengthening reagents of nitrifying-denitrifying bacteria and polyphosphate bacteria are added; an aerobic section is built after the anoxic section to promote the conversion of ammonia nitrogen into nitrate and promote the absorption of phosphorus, and ester fillers are used as filling materials in the aerobic stage; the polyphosphate bacteria strengthened and activated in the anoxic section take up phosphorus, so that microorganisms with phosphorus accumulation are released into the water body and participate in the metabolic process of the microorganisms; in addition, an aerobic stage is established to improve the utilization rate of natural dissolved organic matter (DOM); wherein a self-priming pump is provided to balance the water inlet, water outlet and internal circulation of the microbial strengthening technology.

[0041] Example 3

[0042] The in-situ treatment system for enhanced purification of overflow pollution from river outlets in this embodiment has the same basic structure as that of embodiment 2, except that: Figure 2 As shown, a river water side inlet pipe 2.15 is provided on one side of the slope bank. When there is no overflow sewage, the river water can be pumped to the water distribution main channel 2.2 through the river water inlet pump 2.16 on the pipe, thereby playing a side treatment role for the river water; a hydrophilic step 2.17 is also provided in the middle of the multi-level slope protection biofilter tank on the slope bank, aiming to provide a passage path, increase the landscape effect, protect the shore vegetation and improve safety.

[0043] In order to achieve a sufficient purification effect, the magnetic flocculation sedimentation unit 1 and the ecological slope protection purification unit 2 are arranged in sequence in the direction of water flow to form a complete system, and the setting heights are successively reduced, which can achieve the effect of automated management and reduce power loss.

[0044] The hydraulic retention time of the magnetic flocculation sedimentation unit 1 is 15 to 20 minutes; the hydraulic retention time of the ecological slope protection purification unit 2 is 8 to 12 hours.

[0045] The in-situ treatment system for enhanced purification of overflow pollution from river outlets in this embodiment has the following specific steps:

[0046] S1, the overflow sewage lifted by the sewage lifting pump 1.1 is mixed with the composite flocculant polysilicate ferric sulfate while passing through the sewage inlet pipe 1.2, and is initially mixed under the turbulent conditions provided by the sewage's own hydrodynamic force; then it enters the magnetic seed mixing reaction tank 1.3, and gradually forms dense flocs wrapped with magnetic media under the action of the stirrer 1.4; the flocs are pushed to the magnetic flocculation reaction tank 1.10 with the water flow. During this process, the sewage is discharged from the magnetic flocculation inlet pipe 1.11 located in the center of the reaction tank into the reactor from top to bottom. An umbrella-shaped baffle is provided under the water inlet to make the sewage evenly distributed in the tank, and then slowly rises along the entire cross-section of the tank and generates a vortex. The magnetic flocs with magnetic cores settle to the conical sludge hopper at the bottom of the tank under the action of gravity and 80-100mT magnetic field force, and the supernatant is discharged from the orifice overflow weir 1.12 at the top of the tank to the water distribution main channel inlet pipe 2.1.

[0047] S2. The water after magnetic flocculation treatment enters the water distribution main channel 2.2 at the top of the slope in a waterfall manner through the water distribution main channel inlet pipe 2.1. After being collected in the water distribution main channel 2.2, it is distributed to the primary slope protection biological filter 2.3 on the slope bank by the water distribution branch pipe 2.14. After being treated by the permeable reaction wall 2.7 on one side of the filter, the water falls from the overflow plate 2.11 below to the secondary slope protection biological filter 2.4, and then falls from the secondary slope protection biological filter 2.4 to the tertiary slope protection biological filter 2.5 along the same path, until it falls from the tertiary slope protection biological filter 2.5 to the river channel 3.

[0048] S3. When there is no overflow sewage, turn off the sewage lifting pump 1.1, turn on the river water inlet pump 2.16, and pump the river water to the slope top water distribution main channel 2.2 through the river water side inlet pipe 2.15, while maintaining the activity of microorganisms in the biological filter and artificial wetland plants, further improve the water quality of the river water; when it rains next time, turn off the river water inlet pump 2.16 and repeat the steps of overflow sewage treatment.

[0049] Example 4

[0050] The in-situ treatment system for enhanced purification of overflow pollution from river outlets in this embodiment has the same basic structure as that of Embodiment 3. The specific implementation steps for the overflow sewage from the river outlets are as follows:

[0051] The overflow sewage at the river outlet is first intercepted by the sewage lifting pump 1.1 and flows to the magnetic flocculation sedimentation unit 1. In this process, the overflow sewage is preliminarily mixed with the composite flocculant polysilicate ferric sulfate while passing through the sewage inlet pipe 1.2, and then enters the magnetic seed mixing reaction tank 1.3 to further stir and mix with the magnetic seed, wherein the flocculant dosing device 1.5 controls the content of the composite flocculant polysilicate ferric sulfate in the sewage to be 3-6 mg / L, and the magnetic separator 1.8 adds magnetic seed to the magnetic seed mixing reaction tank 1.3 through the magnetic seed dosing point 1.9, and the dosing amount is 100-200 mg / L; the dense flocs wrapped with magnetic medium formed in the magnetic seed mixing reaction tank 1.3 are pushed to the magnetic flocculation reaction tank 1.10 with the water flow, and mud and water are separated under the condition of a magnetic field strength of 80-100 mT, and finally the supernatant is discharged from the orifice overflow weir 1.12 at the top of the tank. In view of the characteristics of large pollution load and high suspended solid concentration of overflow sewage at the discharge port, a magnetic flocculation sedimentation unit 1 with high treatment efficiency and small footprint is selected as the front-end pretreatment system of overflow pollution at the end of the drainage system, which can effectively remove insoluble solid suspended pollutants and reduce pollution load: remove 93% to 97% of the total influent SS and make the effluent SS ≤12mg / L, remove 45% to 55% of the total influent COD and make the effluent COD ≤150mg / L, remove 88% to 95% of the total influent total phosphorus and make the effluent TP ≤0.8mg / L, and the total hydraulic retention time ≤20min.

[0052] The water treated by magnetic flocculation flows into the water distribution main channel 2.2 at the top of the slope in the form of a waterfall through the water distribution main channel inlet pipe 2.1. After being collected in the water distribution main channel 2.2, it is distributed to the primary slope protection biological filter 2.3 on the slope bank by the water distribution branch pipe 2.14. After being treated by the permeable reaction wall 2.7 on one side of the filter, the water falls from the overflow plate 2.11 below to the secondary slope protection biological filter 2.4, and then falls from the secondary slope protection biological filter 2.4 to the tertiary slope protection biological filter 2.5 along the same path, until it falls from the tertiary slope protection biological filter 2.5 to the river channel 3. The hydraulic retention time of sewage in the ecological slope protection purification unit 2 is 8 to 12 hours. In this process, the gravel filler layer 2.8 at the bottom of the slope protection biofilter plays a role of physical support and stability in the filter; the expanded clay filler layer 2.9 is located above the gravel filler layer 2.8, and its porous structure and large surface area are conducive to biological attachment and microbial degradation, and the pore structure in the expanded clay filler layer 2.9 helps to increase the transfer of oxygen and the gas exchange between the water body and the atmosphere, promoting the growth and metabolism of organisms in the filter; the wetland plants 2.10 planted on the top of the slope protection biofilter can not only make the ecological slope protection purification unit 2 compatible with the surrounding landscape, but the plant roots can also absorb and purify harmful substances in the water, and cooperate with other systems to reduce N and P nutrients in the water body, and promote the biodegradation of pollutants; the high-efficiency adsorption net filled in the permeable reaction wall 2.7 The functional materials can effectively remove pollutants in the water through adsorption, biodegradation and physical interception, thereby improving the purification effect of the slope protection biofilter; the water distribution main channel-slope protection biofilters at all levels-river channel are arranged from top to bottom into a multi-level stepped combination system using the slope, so that water flow is transferred between the treatment facilities at all levels in the form of waterfalls, and the impact of the water flow and the contact of the gas-liquid interface are used to increase the oxygen content in the water body to solve the problem of low dissolved oxygen content in overflow sewage; the microbial automatic activation inoculation device 2.6 is used to amplify the local beneficial microorganisms in the system through the circulating water inlet 2.13 and the circulating water outlet 2.12 set in the water distribution main channel 2.2, so as to achieve in-situ degradation of water pollutants and simultaneous reduction of bottom sediments, thereby improving the efficiency of microbial degradation and removal of pollutants in the water body. After deep treatment in the ecological slope protection purification unit 2, the overflow sewage finally achieves the key effluent effect: SS≤8mg / L, COD≤23mg / L, TP≤0.2mg / L, ammonia nitrogen≤1mg / L, dissolved oxygen≥3mg / L, and the effluent can reach the surface quasi-Class IV water standard in the "Surface Water Environmental Quality Standard (GB 3838-2002)".

Claims

1. An in-situ treatment system for enhanced purification of overflow pollution from river outlets, characterized by: It comprises a magnetic flocculation sedimentation unit (1) and an ecological slope protection purification unit (2), wherein the magnetic flocculation sedimentation unit (1) and the ecological slope protection purification unit (2) are arranged in sequence in the direction of water flow to form a complete system.

2. The in-situ treatment system for enhanced purification of overflow pollution from river outlets according to claim 1, characterized in that: The magnetic flocculation sedimentation unit (1) comprises a sewage lifting pump (1.1), a sewage inlet pipe (1.2), a magnetic seed mixing reaction tank (1.3), a flocculant dosing device (1.5), a magnetic separator (1.8) and a magnetic flocculation reaction tank (1.10). The flocculant dosing device (1.5) stores a composite flocculant, polysilicate ferric sulfate, and dosing the flocculant into the sewage inlet pipe (1.2) through a flocculant dosing point (1.7). A metering pump (1.6) is provided on the flocculant dosing point (1.7) to control the content of the composite flocculant polysilicate ferric sulfate in the sewage to be 3 to 6 mg / L. The magnetic separator (1.8) dosing magnetic seeds into the magnetic seed mixing reaction tank (1.3) through a magnetic seed dosing point (1.9), and the amount of magnetic seeds added into the magnetic seed mixing reaction tank (1.3) is 100 to 200 mg / L.

3. The in-situ treatment system for enhanced purification of overflow pollution from river outlets according to claim 1 is characterized by: The ecological slope protection purification unit (2) comprises a water distribution main channel inlet pipe (2.1), a water distribution main channel (2.2) arranged at the top of the slope and a microorganism automatic activation inoculation device (2.6), a primary slope protection biological filter (2.3) arranged at the slope bank, a secondary slope protection biological filter (2.4) and a tertiary slope protection biological filter (2.5). The water inlet pipe (2.1) of the water distribution main channel is arranged above the water distribution main channel (2.2), so that the water flow after the magnetic flocculation treatment enters the water distribution main channel (2.2) in a waterfall manner; the first-level slope protection biological filter (2.3), the second-level slope protection biological filter (2.4) and the third-level slope protection biological filter (2.5) are arranged in a stepped manner on the high platform, the middle platform and the low platform of the slope bank, and the height difference between adjacent platforms is 0.5 to 1 meter. The slope protection biofilter is provided with a gravel filling layer (2.8), a ceramsite filling layer (2.9) and wetland plants (2.10) from bottom to top; the gravel particle size in the gravel filling layer (2.8) is 20-40 mm, and the filling thickness is 0.2-0.3 m; the ceramsite particle size in the ceramsite filling layer (2.9) is 10-30 mm, and the filling thickness is 0.1-0.2 m; the wetland plants (2.10) planted on the filling layer should be suitable for the landscape, and should achieve the dual effects of purifying water quality and being beautiful. The slope protection biofilter is provided with a permeable reaction wall (2.7) on the side close to the river channel. The outer layer of the permeable reaction wall (2.7) is composed of a grid frame, and the interior is filled with a high-efficiency adsorption and purification functional material; the high-efficiency adsorption and purification functional material is composed of iron-modified biochar, clay minerals, and adhesives mixed and granulated, and the distribution ratio of each component is: iron-modified biochar 50% to 60%, clay minerals 20% to 30%, and adhesives 10% to 20%; the high-efficiency adsorption and purification functional material filled in each level of the slope protection biofilter is 10% to 20%. The particle size decreases step by step along the water flow direction. Specifically, the particle size of the high-efficiency adsorption and purification functional material in the first-level slope protection biological filter (2.3) is 15-20 mm, the particle size of the high-efficiency adsorption and purification functional material in the second-level slope protection biological filter (2.4) is 8-15 mm, and the particle size of the high-efficiency adsorption and purification functional material in the third-level slope protection biological filter (2.5) is 3-8 mm. The filling thickness of the high-efficiency adsorption and purification functional material is 0.15-0.2 m, and the filling height is 0.6-0.8 m. The microbial automatic activation inoculation device (2.6) amplifies local beneficial microorganisms in the system through a circulating water inlet (2.13) and a circulating water outlet (2.12) provided in the water distribution main channel (2.2), thereby achieving in-situ degradation of water pollutants and simultaneous reduction of bottom sludge, thereby improving the efficiency of water microbial degradation and removal of pollutants.

4. The in-situ treatment system for enhanced purification of overflow pollution from river outlets according to claim 1 is characterized by: The hydraulic retention time of the magnetic flocculation sedimentation unit (1) is 15 to 20 minutes; the hydraulic retention time of the ecological slope protection purification unit (2) is 8 to 12 hours.

5. An in-situ treatment system for enhanced purification of overflow pollution from river outlets, characterized in that: The steps are: S1. The overflow sewage lifted by the sewage lifting pump (1.1) is mixed with the composite flocculant polyferric silicate sulfate while passing through the sewage inlet pipe (1.2), and is initially mixed under the turbulent conditions provided by the sewage's own hydrodynamic force; then it enters the magnetic seed mixing reaction tank (1.3), and gradually forms dense flocs wrapped with magnetic media under the action of the stirrer (1.4); the flocs are pushed to the magnetic flocculation reaction tank (1.10) along with the water flow. During this process, the sewage is discharged from the magnetic flocculation inlet pipe (1.11) located at the center of the reaction tank into the reactor from top to bottom. An umbrella-shaped baffle is provided under the water inlet to make the sewage evenly distributed in the tank, and then it slowly rises along the entire cross-section of the tank and generates a vortex. The magnetic flocs with magnetic cores settle to the conical sludge hopper at the bottom of the tank under the action of gravity and a magnetic field force of 80 to 100 mT, and the supernatant is discharged from the orifice overflow weir (1.12) at the top of the tank to the water distribution main canal inlet pipe (2.1). S2. The water flow after the magnetic flocculation treatment enters the water distribution main channel (2.2) at the top of the slope in a waterfall manner through the water distribution main channel inlet pipe (2.1), and is collected in the water distribution main channel (2.2) and distributed to the primary slope protection biological filter (2.3) on the slope bank through the water distribution branch pipe (2.14). After the water flow is treated by the permeable reaction wall (2.7) on one side of the filter, it falls from the overflow plate (2.11) below to the secondary slope protection biological filter (2.4), and then falls from the secondary slope protection biological filter (2.4) to the tertiary slope protection biological filter (2.5) along the same path, until it falls from the tertiary slope protection biological filter (2.5) into the river channel (3). S3. When there is no overflow sewage, turn off the sewage lifting pump (1.1), turn on the river water inlet pump (2.16), and pump the river water to the main water distribution channel (2.2) on the top of the slope through the river water side inlet pipe (2.15), while maintaining the activity of microorganisms in the biological filter and artificial wetland plants, further improving the water quality of the river water; when it rains next time, turn off the river water inlet pump (2.16) and repeat the steps of overflow sewage treatment.

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