Multistage stabilization pond and bio-overflow dam combined riverway restoration system and method

Abstract

The present disclosure relates to the technical field of environmental protection, and provides a multi-stage stabilization pond and biological overfall dam combined riverway restoration system and method. The system adopts a combination of an ecological combined multi-stage stabilization pond system and a multi-medium biological overfall dam system to carry out in-situ treatment on riverway water bodies. In the direction of the riverway water flow, the ecological combined multi-stage stabilization pond system is constructed before the multi-medium biological overfall dam system. The ecological combined multi-stage stabilization pond system is used to remove the main pollutants of the riverway water bodies, and the multi-medium biological overfall dam system is used to carry out deep denitrification and phosphorus removal on the riverway water bodies. By using the present disclosure, the riverway water quality indexes such as SS, COD, NH3-N, TN and TP are significantly reduced, the riverway ecosystem is restored, and the requirements of the examination section water quality reaching the standard are met. Meanwhile, the process has the advantages of short construction period, no additional land occupation and low operation cost.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of environmental protection, and particularly relates to a multi-stage stabilization pond and biological overflow dam combined riverway restoration system and method. BACKGROUND

[0002] Small and medium-sized riverways are important components of urban ecosystems and play an important role in urban development. At present, due to imperfect rainwater and sewage collection systems in villages and towns, an increasing number of residents along the river, and other reasons, a large amount of domestic sewage, industrial wastewater, and agricultural non-point source pollution is discharged into the riverway, which increases the content of nitrogen and phosphorus in the riverway and causes the water pollution load to be too high. The riverway gradually becomes a pollution channel, exceeds the water environmental capacity of the riverway, and causes water quality deterioration. Some riverway water bodies are degraded to inferior V-class, and even become black and odorous water bodies, which affect the water quality of the riverway and the surrounding landscape environment.

[0003] In China, traditional riverway treatment mainly includes planting aquatic plants, building ecological floating islands, and riverway water body aeration. The scheme mainly aims to restore the ecological function of the riverway, rebuild the ecological community, and restore the self-purification capacity of the water body. However, the ecological restoration period of the scheme is relatively long, and it is difficult to meet the urgent demand of people for water quality improvement. In addition, the biological filter bed is an important measure for riverway treatment technology. It mainly combines different material carriers and applies composite bacteria for treatment. The carrier filler is generally ordinary mineral material, and the performance is poor. In the case of large water flow in the flood season, the in-situ biological filter is easy to cause water level rise and affect the upstream. The ex-situ biological filter bed is complex to operate and needs to rely on external equipment, which increases the cost. The carbon-nitrogen ratio (C / N) of most riverways is low, and the cost of additional carbon source is high and easy to block the filter bed. Therefore, the supply of carbon source becomes a limiting factor for nitrification and denitrification in the biological filter bed, and the treatment effect of phosphorus by simply relying on the nitrification and denitrification of the biological filter bed is poor.

[0004] Therefore, the existing riverway ecological restoration process needs to seek a high-efficiency riverway ecological restoration combined process with good comprehensive effect and simple operation on the basis of the traditional restoration process to solve the problems of poor water quality and ecological damage of small and medium-sized riverways, so as to achieve water quality standard and riverway ecological restoration at the examination section. SUMMARY

[0005] (I) Technical problems to be solved

[0006] Therefore, the main purpose of the present disclosure is to provide a multi-stage stabilization pond and biological overflow dam combined riverway restoration system and method to solve the above technical problems.

[0007] (II) Technical solutions

[0008] In a first aspect of the present disclosure, a multi-stage stabilization pond and biological overfall dam combined riverway restoration system is provided, which uses a combination of an ecological combined multi-stage stabilization pond system and a multi-medium biological overfall dam system to treat riverway water in situ, wherein: in the direction of the riverway water flow, the ecological combined multi-stage stabilization pond system is constructed before the multi-medium biological overfall dam system, the ecological combined multi-stage stabilization pond system is used to remove the main pollutants of the riverway water, and the multi-medium biological overfall dam system is used to deeply remove nitrogen and phosphorus from the riverway water.

[0009] According to an embodiment of the present disclosure, the ecological combined multi-stage stabilization pond system sequentially includes a flocculation sedimentation zone 1, an ecological floating island zone 2, and a solar micro-nano aeration zone 3 in the direction of the riverway water flow, wherein: the contaminated water body flows into the ecological combined multi-stage stabilization pond system, first enters the flocculation sedimentation zone 1, the water body is mixed and reacted with a flocculant in the flocculation sedimentation zone 1, the suspended solids SS are reduced to below 20-30 mg / L, and the total phosphorus TP is reduced to 0.4-0.5 mg / L; the effluent of the flocculation sedimentation zone 1 enters the ecological floating island zone 2, the water body is absorbed by the plant root system, the microorganisms are quickly biofilm on the biological carbon fiber and the water purification carrier, and the adsorption of the biological carbon fiber and the water purification carrier reduces the chemical oxygen demand COD, ammonia nitrogen NH3-N, and total phosphorus TP indicators of the water body; then the water body enters the solar micro-nano aeration zone 3, the water body itself dissolved oxygen DO is increased, the dissolved oxygen DO reaches 3-5 mg / L, the suspended solids SS are reduced to 15-20 mg / L, the TP is reduced to 0.3-0.4 mg / L, and the chemical oxygen demand COD is reduced to 40-50 mg / L.

[0010] According to an embodiment of the present disclosure, the flocculant includes 100 mg / L of polyaluminum chloride PAC and 0.5 mg / L of polyacrylamide PAM.

[0011] According to an embodiment of the present disclosure, the multi-medium biological overfall dam system uses an overfall low dam system and a multi-medium biological filter bed, the multi-medium biological filter bed is constructed inside the overfall low dam system, in the flood season, the water body flows over the low dam through the overfall low dam system, and in the non-flood season, the water body is treated by secondary nitrification and denitrification through the multi-medium biological filter bed inside the overfall low dam system.

[0012] According to an embodiment of the present disclosure, the overfall low dam system uses a bottom-up water inlet mode, the water inlets and outlets are staggered, ecological concrete slopes 9 are arranged on both sides of the overfall low dam system to prevent dam breakage, the multi-medium biological filter bed sequentially includes a first aerobic filler zone 5, a first anaerobic filler zone 6, a second aerobic filler zone 7, and a second anaerobic filler zone 8 in the direction from the water inlet to the water outlet, the water body treated by the ecological combined multi-stage stabilization pond system enters the multi-medium biological filter bed from the first aerobic filler zone 5, and flows out of the multi-medium biological filter bed from the second anaerobic filler zone 8.

[0013] According to the embodiment of the present disclosure, the first and second aerobic filler zones 5 and 7 are filled with multi-medium biological ceramsite and maintain the concentration of dissolved oxygen DO by using a solar aerator 10; the first and second anaerobic filler zones 6 and 8 are filled with modified porous microbial immobilized filler; the first aerobic filler zone 5 and the first anaerobic filler zone 6 are used to realize adsorption / primary cell oxidation / nitrification, adsorption / denitrification; the second aerobic filler zone 7 and the second anaerobic filler zone 8 are used to realize adsorption / primary cell oxidation / nitrification, adsorption / denitrification again, so as to realize the nitrification-denitrification process twice synchronously.

[0014] According to the embodiment of the present disclosure, the multi-medium biological ceramsite is prepared by the following method: Hangjin soil is mixed with sodium hydroxide and calcined at 550°C, the calcined product is stirred and filtered at 70°C, aluminum sulfate is added to the filtrate to adjust the silicon-aluminum atomic molar ratio, and a new type of artificial molecular sieve is prepared by crystallization at 100-110°C, and the multi-medium biological ceramsite is prepared by using the molecular sieve as raw material and fly ash, sawdust, clay and calcium carbonate as auxiliary materials. The specific surface area of the multi-medium biological ceramsite is 1.55 times that of ordinary ceramsite, which is beneficial to the adsorption of pollutants and the rapid biofilm formation of microorganisms, and the content of metallic iron and Fe3C in the material is high, which has obvious primary cell effect, and the generation of Fe(OH)2 and Fe(OH)3 can promote the nitrification reaction.

[0015] According to the embodiment of the present disclosure, the modified porous microbial immobilized filler is prepared by the following method: polyurethane is used as raw material, cellulose natural carbon source material is added, and polyurethane macroporous micro-degradable polymer is generated by foaming, granulation, opening and crosslinking. The pore size of the filler is 2-7mm, the specific surface area is 33x10 4 m 2 / m 3 , the biomass is 25-35g / L, and the wet density is 1g / cm 3 ; in low C / N ratio water, the carbon source material in the modified porous microbial immobilized filler can be slowly hydrolyzed to release carbon source for denitrification, and the density of the modified porous microbial immobilized filler is close to water, which is in a suspended state in water. The scouring disturbance of water flow can avoid the later flushing maintenance.

[0016] According to the embodiment of the present disclosure, the first aerobic filler area 5, the first anaerobic filler area 6, the second aerobic filler area 7 and the second anaerobic filler area 8 are separated by the partition wall 11, two adjacent filler areas are communicated from top to bottom by the flow guide pipe, the water distribution pipe is arranged at the bottom of the flow guide pipe to realize water inlet at the bottom of each filler area and water distribution; the aeration pipe of the aerobic area is located at the bottom, and the water and the air are in the same direction; the water body enters the first aerobic filler area 5 through the water inlet 15, then enters the first anaerobic filler area 6 through the flow guide pipe 12 from top to bottom, the water body is fully contacted with the filler 14 through the bottom water distribution pipe 13, then sequentially passes through the second aerobic filler area 7 and the second anaerobic filler area 8, and is discharged through the water outlet 16.

[0017] According to the embodiment of the present disclosure, the water body flows into the multi-medium biological overfall dam system, first enters the first aerobic filler area 5 through the water inlet at the bottom and the water distribution pipe, stays for 15-30 min, contacts with the beneficial microorganisms in the first aerobic filler area 5 to perform the nitrification reaction, the dissolved oxygen DO is controlled by the aerator in the aeration area, the dissolved oxygen DO in the first aerobic filler area 5 is maintained at 3-5 mg / L, the beneficial microorganisms perform the aerobic nitrification reaction and the biological ceramsite primary cell oxidation reaction, most of the ammonia nitrogen is converted into nitrate nitrogen, and most of the organic matter and total phosphorus TP are removed; the water body enters the first anaerobic filler area 6 through the flow guide pipe from top to bottom, is fully contacted with the biological immobilized filler through the bottom water distribution pipe, the water body stays for 20-40 min, performs the adsorption / denitrification in the first anaerobic filler area 6, most of the nitrate nitrogen and nitrite nitrogen are converted into nitrogen gas and removed; then the water body enters the second aerobic filler area 7 through the flow guide pipe to perform secondary oxygen dissolution, the dissolved oxygen DO of the water body is increased to 3-5 mg / L, the adsorption / nitrification / primary cell oxidation is realized again; next, the water body enters the second anaerobic filler area 8 to realize the adsorption / denitrification again, finally, the concentration of suspended solids SS is reduced to 10-15 mg / L, the concentration of chemical oxygen demand COD is 30-40 mg / L, the concentration of NH3-N is 0.2-0.5 mg / L, and the concentration of total phosphorus TP is 0.3-0.4 mg / L, which meets the surface water V-class and above standards, and the effluent is discharged through the upper water outlet of the second anaerobic filler area 8.

[0018] According to another aspect of the present disclosure, a multi-stage stable pond and biological overfall dam combined riverway restoration method is provided, which adopts the multi-stage stable pond and biological overfall dam combined riverway restoration system, and the method comprises the following steps:

[0019] The contaminated water body flows into the ecological combined multi-stage stable pond system, first enters the flocculation and sedimentation area 1, the water body is mixed and reacted with the flocculating agent in the flocculation and sedimentation area 1, and the suspended solids SS and the total phosphorus TP in the water body are reduced;

[0020] The effluent from the flocculation and sedimentation zone 1 enters the ecological floating island zone 2, is absorbed by the plant roots, and the microorganisms are quickly attached to the biological carbon fiber and water purification carrier, and the adsorption of the biological carbon fiber and water purification carrier realizes the reduction of the chemical oxygen demand COD, ammonia nitrogen NH3-N and total phosphorus TP indexes of the water body;

[0021] The water body further passes through the solar micro-nano aeration zone 3, and the dissolved oxygen DO of the water body is increased to 3-5 mg / L; the increase of the dissolved oxygen DO effectively reduces the chemical oxygen demand COD and ammonia nitrogen NH3-N content in the water body; the nano bubbles have the effects of demulsification, flocculation and air flotation, and can effectively separate suspended solids SS, algae and oil;

[0022] The water body flows into the multi-medium biological overflow dam system, first enters the first aerobic filler zone 5 through the water distribution pipe from the dam inlet, and the hydraulic retention time is 20-60 min; in the first aerobic filler zone 5, the water body is contacted with beneficial microorganisms to perform nitrification reaction, and the dissolved oxygen DO is controlled by the aerator; the dissolved oxygen DO in the first aerobic filler zone 5 is maintained at 3-5 mg / L, and the beneficial microorganisms perform aerobic nitrification reaction and biological ceramic granule primary cell oxidation reaction, thereby converting most of the ammonia nitrogen into nitrate nitrogen and adsorbing and removing organic matter and total phosphorus TP;

[0023] The water body passes through the top-down flow guide pipe and enters the first anaerobic filler zone 6, and is fully contacted with the microbial immobilized carrier through the bottom water distribution pipe; the hydraulic retention time is 30-60 min; in the first anaerobic filler zone 6, adsorption / denitrification is performed, most of the nitrate nitrogen and nitrite nitrogen is converted into nitrogen gas and removed; in the water body with low carbon-nitrogen ratio C / N, the cellulose in the modified porous microbial immobilized filler can be hydrolyzed under the action of microorganisms, thereby releasing the required carbon source for denitrification;

[0024] Next, the water body flows into the second aerobic filler zone 7 through the flow guide pipe to perform secondary dissolved oxygen, the dissolved oxygen DO of the water body is increased to 3-5 mg / L, adsorption / nitrification / primary cell oxidation is realized again, the water body enters the second anaerobic filler zone 8 to realize adsorption / denitrification again, and finally the indexes of suspended solids SS, chemical oxygen demand COD, ammonia nitrogen NH3-N, total nitrogen TN of various forms of inorganic and organic nitrogen in the water body and total phosphorus TP are significantly reduced, and the effluent meets the discharge standard.

[0025] According to the embodiment of the present disclosure, before the contaminated water body flows into the ecological combined multi-stage stable pond system, the high-efficiency denitrification and phosphorus removal bacterial agent is also put into the biological filter bed, is cultured and trained for 5-7 days, the microbial attachment to the filler is realized, the cellulose carbon source in the modified porous microbial immobilized filler in the first anaerobic filler zone 6 and the second anaerobic filler zone 8 is slowly hydrolyzed under the action of microorganisms, and the carbon source for anaerobic denitrification is provided.

[0026] (III) Advantages

[0027] According to the embodiments of the present disclosure, the multi-stage stable pond and biological overflow dam combined riverway restoration system and method provided by the present disclosure has the following advantages and benefits:

[0028] ①The multi-stage stable pond and biological overflow dam combined riverway restoration system and method provided by the present disclosure belongs to in-situ treatment of riverway water bodies, without the need to intercept and extract water bodies for ex-situ treatment, without additional land occupation, simplified process, and reduced cost. The front-end ECSP system and the end MBOD system are complementary, which can realize the removal of suspended solids, oil, and algae in water bodies, while improving the dissolved oxygen DO and reducing the chemical oxygen demand COD and nitrogen and phosphorus removal, so that the water quality is significantly and rapidly improved. It also has the advantages of restoring the water ecological system, improving the self-purification capacity of the water body, and realizing the ecological landscape restoration of the riverway.

[0029] ②The multi-stage stable pond and biological overflow dam combined riverway restoration system and method provided by the present disclosure realizes the coupling of the low-dam overflow system and the multi-medium biological filter bed system. In the non-flood season, the treatment is mainly carried out, and in the flood season, the flood discharge is mainly carried out. In special cases with large water flow, it will not affect the upstream.

[0030] ③The multi-stage stable pond and biological overflow dam combined riverway restoration system and method provided by the present disclosure realizes the series connection of aerobic, anaerobic, aerobic, and anaerobic in the biological filter bed system in the dam, which is equivalent to the first-stage aerobic and anaerobic effluent reflux, improves the treatment capacity, and realizes the secondary nitrification and denitrification by means of the water flow itself, so that the construction process is greatly simplified, the treatment efficiency is improved, and the cost is reduced.

[0031] ④The multi-stage stable pond and biological overflow dam combined riverway restoration system and method provided by the present disclosure fills the aerobic zone with multi-medium biological ceramsite made of cheap materials such as fly ash and Hangzhou cotton soil, which can realize adsorption and microbial biofilm formation, and also has the function of primary cell oxidation of ammonia nitrogen, promoting nitrification. The modified porous microbial immobilized filler in the anaerobic zone is made of polyurethane and added with degradable carbon sources such as cellulose, which can provide carbon sources for the denitrification of microorganisms in the low C / N ratio riverway, promoting the denitrification process; the density of the filler is close to that of water, and it is in a suspended state in water, which can avoid the need for later flushing and maintenance.

[0032] In summary, the multi-stage stable pond and biological overflow dam combined riverway restoration system and method provided by the present disclosure can significantly reduce the riverway water quality indicators such as suspended solids SS, chemical oxygen demand COD, ammonia nitrogen NH3-N, total nitrogen TN, and total phosphorus TP, restore the riverway ecological system, and meet the requirements of water quality assessment section standards, while also having the advantages of short construction period, no additional land occupation, and low operating cost. Attached Figure Description

[0033] The above and other objects, features and advantages of this disclosure will become clearer from the following description of embodiments with reference to the accompanying drawings, in which:

[0034] Figure 1 This is a schematic diagram of a multi-stage stabilization pond and biological overflow dam combined river restoration system according to an embodiment of this disclosure.

[0035] Figure 2 This is a cross-sectional view of the low dam overflow system in a multi-stage stabilization pond and biological overflow dam combined river restoration system according to an embodiment of the present disclosure.

[0036] Figure 3 This is a cross-sectional view of a multi-media biofilter bed in a combined river restoration system of a multi-stage stabilization pond and a biological overflow dam, according to an embodiment of this disclosure.

[0037] Figure 4 This is a graph showing the changes in water quality indicators after river restoration using a combination of multi-stage stabilization ponds and biological overflow dams, according to an embodiment of this disclosure.

[0038] [Figure Labels]:

[0039] 1. Flocculation sedimentation tank, 2. Ecological floating island area, 3. Solar micro-nano aeration area, 4. Shoreline vegetation area, 5. First aerobic packing area, 6. First anaerobic packing area, 7. Second aerobic packing area, 8. Second anaerobic packing area, 9. Ecological slope protection, 10. Solar aerator, 11. Partition wall, 12. Guide pipe, 13. Water distribution pipe, 14. Packing material, 15. Inlet, 16. Outlet. Detailed Implementation

[0040] The embodiments of the present disclosure will now be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the disclosure. In the following detailed description, numerous specific details are set forth to provide a thorough understanding of the embodiments of the present disclosure for ease of explanation. However, it will be apparent that one or more embodiments may be practiced without these specific details. Furthermore, descriptions of well-known structures and techniques are omitted in the following description to avoid unnecessarily obscuring the concepts of the present disclosure.

[0041] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit this disclosure. The terms “comprising,” “including,” etc., as used herein indicate the presence of the stated features, steps, operations, and / or components, but do not exclude the presence or addition of one or more other features, steps, operations, or components.

[0042] All terms used herein, including technical and scientific terms, have the meanings commonly understood by one of ordinary skill in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning that is consistent with the context of the specification, and should not be interpreted in an idealized or overly formal way.

[0043] Embodiments of the present disclosure provide a multi-stage stable pond and biological overfall dam combined riverway restoration system and method. Wherein the multi-stage stable pond and biological overfall dam combined riverway restoration system is as shown in Figure 1 Figure 1 is a schematic diagram of the multi-stage stable pond and biological overfall dam combined riverway restoration system according to the embodiments of the present disclosure. It should be noted that Figure 1 as shown is only an example of an application scenario to which the embodiments of the present disclosure can be applied, to help those skilled in the art understand the technical content of the present disclosure, but does not mean that the embodiments of the present disclosure cannot be applied to other environments or scenarios.

[0044] As shown in Figure 1 , the multi-stage stable pond-biological overfall dam combined riverway restoration system uses a combination of an ecological combined multi-stage stable pond system (ECSP) and a multi-medium biological overfall dam system (MBOD) for in-situ treatment of river water bodies, wherein, in the direction of the river water flow, the ecological combined multi-stage stable pond system is constructed before the multi-medium biological overfall dam system, the ecological combined multi-stage stable pond system is used to remove the main pollutants of the river water body, and the multi-medium biological overfall dam system is used for deep denitrification and phosphorus removal of the river water body.

[0045] In the embodiments of the present disclosure, the ecological combined multi-stage stable pond system sequentially includes a flocculation sedimentation zone 1, an ecological floating island zone 2, and a solar micro-nano aeration zone 3 in the direction of the river water flow, wherein: the contaminated water body flows into the ecological combined multi-stage stable pond system, first enters the flocculation sedimentation zone 1, the water body is mixed and reacted with the flocculant in the flocculation sedimentation zone 1, the suspended solids SS are reduced to below 20-30 mg / L, and the total phosphorus TP is reduced to 0.4-0.5 mg / L; optionally, the flocculant includes 100 mg / L of polyaluminum chloride PAC and 0.5 mg / L of polyacrylamide PAM. The effluent of the flocculation sedimentation zone 1 enters the ecological floating island zone 2, the chemical oxygen demand COD, ammonia nitrogen NH3-N, and total phosphorus TP indicators of the water body are reduced through plant root absorption, rapid biofilm formation of microorganisms on biological carbon fiber and water purification carrier, and adsorption of biological carbon fiber and water purification carrier; then the water body enters the solar micro-nano aeration zone 3, the water body's own dissolved oxygen DO is increased, the dissolved oxygen reaches 3-5 mg / L, the suspended solids SS are reduced to 15-20 mg / L, the total phosphorus TP is reduced to 0.3-0.4 mg / L, and the chemical oxygen demand COD is reduced to 40-50 mg / L.

[0046] ​In the embodiment of the present disclosure, the multi-medium biological overfall dam system adopts Figure 2 the overfall low dam system shown in Figure 3 and the multi-medium biological filter bed shown in, which is built inside the overfall low dam system. In flood season, water overflows the low dam through the overfall low dam system. In non-flood season, the water is treated by secondary nitrification and denitrification through the multi-medium biological filter bed inside the overfall low dam system.

[0047] As shown in Figure 2 , the overfall low dam system adopts a bottom-up water inlet mode, and the water inlets and outlets are staggered. Ecological concrete slopes 9 are used on both sides of the overfall low dam system to prevent dam breakage. In the embodiment of the present disclosure, the construction height of the overfall low dam system should not be too high, and it is usually appropriate to be 30-50 cm higher than the average water level of the river channel in non-flood season. The size of the water inlets and outlets is designed according to the maximum water flow in non-flood season.

[0048] In the embodiment of the present disclosure, the multi-medium biological filter bed includes, in order from the water inlet to the water outlet, a first aerobic filler area 5, a first anaerobic filler area 6, a second aerobic filler area 7, and a second anaerobic filler area 8, as shown in Figure 1 The water treated by the ecological combined multi-stage stabilization pond system enters the multi-medium biological filter bed from the first aerobic filler area 5 and flows out of the multi-medium biological filter bed from the second anaerobic filler area 8.

[0049] In the embodiment of the present disclosure, the first aerobic filler area 5 and the second aerobic filler area 7 are filled with multi-medium biological ceramsite, and a solar-powered aerator 10 is used to maintain the concentration of dissolved oxygen DO. The multi-medium biological ceramsite is prepared by the following method: Hangjin soil is mixed with sodium hydroxide and calcined at 550°C. The calcined product is stirred and filtered at 70°C. Aluminum sulfate is added to the filtrate to adjust the silicon-aluminum atomic molar ratio. A new type of artificial molecular sieve is prepared by crystallization at 100-110°C. The multi-medium biological ceramsite is prepared using the molecular sieve as the raw material and fly ash, sawdust, clay, and calcium carbonate as auxiliary materials. The specific surface area of the multi-medium biological ceramsite is 1.55 times that of ordinary ceramsite, which is beneficial to the adsorption of pollutants and the rapid biofilm formation of microorganisms. At the same time, the material has high content of metallic iron and Fe3C, which has obvious primary cell effect, and the generated Fe(OH)2 and Fe(OH)3 can promote nitrification.

[0050] In the embodiment of the present disclosure, the first anaerobic filler area 6 and the second anaerobic filler area 8 are filled with modified porous microbial immobilized filler. The modified porous microbial immobilized filler is prepared by the following method: polyurethane is used as the raw material, and cellulose natural carbon source material is added. After foaming, granulation, opening, and crosslinking, a polyurethane macroporous micro-degradable polymer is generated. The pore size of the filler is 2-7 mm, the specific surface area is 33×10 4 m2 / m 3 Biomass: 25-35 g / L, wet density 1 g / cm 3 In a low carbon-nitrogen ratio (C / N) water body, the carbon source material in the modified porous microbial immobilization filler can be slowly hydrolyzed to release carbon source for denitrification process, and the density of the modified porous microbial immobilization filler is close to water, which is in a suspended state in water. The scouring disturbance of water flow can avoid the late flushing maintenance.

[0051] In the embodiments of the present disclosure, the first aerobic filler area 5 and the first anaerobic filler area 6 are used to realize adsorption / primary cell oxidation / nitrification, adsorption / denitrification. The second aerobic filler area 7 and the second anaerobic filler area 8 are used to realize adsorption / primary cell oxidation / nitrification, adsorption / denitrification again, to realize the nitrification and denitrification processes synchronously for the second time.

[0052] As shown in Figure 3 The first aerobic filler area 5, the first anaerobic filler area 6, the second aerobic filler area 7 and the second anaerobic filler area 8 are separated by a partition wall 11, and two adjacent filler areas are communicated from top to bottom by a flow guide pipe, and a water distribution pipe is arranged at the bottom of the flow guide pipe to realize water inlet at the bottom of each filler area and water distribution. The aeration pipe of the aerobic area is located at the bottom, and the water and air are in the same direction. The water body enters the first aerobic filler area 5 through the water inlet 15, then enters the first anaerobic filler area 6 through the flow guide pipe 12 from top to bottom, and then the water body and the filler 14 are fully contacted through the bottom water distribution pipe 13, and then sequentially pass through the second aerobic filler area 7 and the second anaerobic filler area 8, and then is discharged through the water outlet 16.

[0053] In the embodiments of this disclosure, water flows into the multi-media biological overflow dam system, first entering the first aerobic packing zone 5 through the bottom inlet and distribution pipe, with a residence time of 15-30 minutes. In the first aerobic packing zone 5, nitrification occurs due to contact with beneficial microorganisms. The dissolved oxygen (DO) is controlled by the aerator in the aeration zone, maintaining it at 3-5 mg / L. Beneficial microorganisms perform aerobic nitrification and biological ceramic particle galvanic cell oxidation, converting most of the ammonia nitrogen into nitrate nitrogen and adsorbing and removing most of the organic matter and total phosphorus (TP). The water then enters the first anaerobic packing zone 6 through a top-down guide pipe, fully contacting the biologically immobilized packing material through the bottom distribution pipe, with a residence time of 20-40 minutes. In the first anaerobic packing zone 6, adsorption / denitrification occurs, converting most of the nitrate and nitrite nitrogen into nitrogen gas for removal. The water then enters the second aerobic packing zone 7 through a diversion pipe for secondary oxygenation, increasing the dissolved oxygen (DO) to 3-5 mg / L, achieving adsorption / nitrification / galvanic cell oxidation again. Next, the water enters the second anaerobic packing zone 8, where adsorption / denitrification occurs again, ultimately reducing the suspended solids (SS) concentration to 10-15 mg / L, chemical oxygen demand (COD) to 30-40 mg / L, ammonia nitrogen (NH3-N) to 0.2-0.5 mg / L, and total phosphorus (TP) to 0.3-0.4 mg / L, meeting or exceeding the Class V surface water standard. The effluent is discharged from the upper outlet of the second anaerobic packing zone 8, meeting all discharge standards.

[0054] based on Figures 1 to 3 The multi-stage stabilization pond and biological floodplain dam combined river restoration system shown in this disclosure also provides a method for river restoration using the multi-stage stabilization pond and biological floodplain dam combined system. This method includes an initial operation phase and a normal operation phase, as detailed below:

[0055] During the initial operation phase, a highly efficient nitrogen and phosphorus removal agent is introduced into the biofilter bed and cultured for 5-7 days to allow microorganisms to attach to the packing material. When the carbon-nitrogen ratio of the water is low, the cellulose carbon source in the modified porous microbial immobilized packing material in the first anaerobic packing zone 6 and the second anaerobic packing zone 8 undergoes slow hydrolysis under the action of microorganisms, providing a carbon source for anaerobic denitrification.

[0056] In the normal operation stage, the contaminated water body flows into the ecological group multi-stage stable pond system, first enters the flocculation sedimentation zone 1, the water body is mixed and reacted with the flocculating agent in the flocculation sedimentation zone 1, the suspended solids SS and total phosphorus TP in the water body are reduced; the effluent of the flocculation sedimentation zone 1 enters the ecological floating island zone 2, is absorbed by the plant root system, the microorganisms are quickly biofilm on the biological carbon fiber and the water purification carrier, and the adsorption of the biological carbon fiber and the water purification carrier reduces the chemical oxygen demand COD, ammonia nitrogen NH3-N and total phosphorus TP indexes of the water body; the water body further passes through the solar micro-nano aeration zone 3, the dissolved oxygen DO of the water body is improved, and the dissolved oxygen DO can reach 3-5 mg / L; the improvement of the dissolved oxygen DO effectively reduces the contents of the chemical oxygen demand COD and ammonia nitrogen NH3-N in the water body; the nano bubbles have the effects of demulsification, flocculation and air flotation, and can effectively separate the suspended solids SS, algae and oil; the water body flows into the multi-medium biological overfall dam system, first enters the first aerobic filler zone 5 through the water inlet of the dam body and the water distribution pipe, the hydraulic retention time is 20-60 min, is contacted with beneficial microorganisms in the first aerobic filler zone 5 to perform nitrification reaction, the dissolved oxygen DO is controlled by the aerator, the dissolved oxygen DO in the first aerobic filler zone 5 is maintained at 3-5 mg / L, the beneficial microorganisms perform aerobic nitrification reaction and biological ceramic pellet original cell oxidation reaction, most of the ammonia nitrogen is converted into nitrate nitrogen, and organic matter and total phosphorus TP are adsorbed and removed; the water body passes through the top-down flow guide pipe and enters the first anaerobic filler zone 6, and is fully contacted with the microorganism immobilized carrier through the bottom water distribution pipe, the hydraulic retention time is 30-60 min, adsorption / denitrification is performed in the first anaerobic filler zone 6, most of the nitrate nitrogen and nitrite nitrogen are converted into nitrogen gas and removed, in the water body with low carbon-nitrogen ratio C / N, the cellulose in the modified porous microorganism immobilized filler can be hydrolyzed under the action of microorganisms, thereby releasing the required carbon source for denitrification; next, the water body flows into the second aerobic filler zone 7 through the flow guide pipe to perform secondary dissolved oxygen, the dissolved oxygen DO of the water body is improved to 3-5 mg / L, adsorption / nitrification / original cell oxidation is realized again, enters the second anaerobic filler zone 8, adsorption / denitrification is realized again, and finally the suspended solids SS, chemical oxygen demand COD, ammonia nitrogen NH3-N, total amount TN of various forms of inorganic and organic nitrogen in the water, and total phosphorus TP indexes are significantly reduced, and the effluent is discharged up to the standard.

[0057] The following further describes the realizability of the multi-stage stable pond and biological overfall dam combined riverway restoration attraction and method provided by the present disclosure through a specific implementation case of a certain polluted riverway in a certain city and water quality effect diagrams.

[0058] The project is located in a certain district of a certain city, and the pollution section number is 34. After the preliminary investigation of the riverway, the characteristics of the riverway are as follows: the water quality is extremely poor, the transparency is very low, there are submerged plants such as golden algae and hornwort in the water body, there are some floating objects in the river, and rainwater runoff and rural domestic sewage are the main pollution sources.

[0059] The monitoring data obtained from sampling and analysis of the river channel prior to restoration are shown in the table below:

[0060] Section name COD (mg / l) [NH3-N (mg / l)] TP (mg / l) First time 34 26 5.15 1.01 Second time 34 50 0.51 1.16 Third time 34 95 2.83 0.78

[0061] The monitoring data above showed that the chemical oxygen demand (COD), ammonia nitrogen (NH3-N), and total phosphorus (TP) in the river exceeded the standards to varying degrees (based on the national Class V surface water standard). The assessment section requires the water quality to reach the Class V water standard. Therefore, the river was restored using the above-mentioned biological and ecological technologies.

[0062] Before the process is in normal operation, microorganisms are first cultured to attach to the packing material. The outlet valve is closed. Denitrifying and phosphorus-removing bacteria are added to the first aerobic packing zone 5, the second aerobic packing zone 7, the first anaerobic packing zone 6, and the second anaerobic packing zone 8. The aerator is turned on to maintain the dissolved oxygen (DO) in the water of the MBOD system at 2-5 mg / L. After culturing for 7 days, the outlet valve is opened.

[0063] River water flows through the ECSP system and into the flocculation sedimentation tank, where it undergoes flocculation treatment with 100 mg / L polyaluminum chloride (PAC) and 0.5 mg / L polyacrylamide (PAM). It then sequentially passes through an ecological floating island zone and a solar-powered micro-nano aeration zone. In the aeration zone, the dissolved oxygen content increases to 5.0 mg / L, suspended solids (SS) decreases to 15 mg / L, total phosphorus (TP) decreases to 0.4 mg / L, and chemical oxygen demand (COD) decreases to 50 mg / L. The water then flows into the MBOD system. Figure 1 In the first aerobic packing zone 5, aerobic biochemical reactions take place, with a dissolved oxygen (DO) concentration of 3.5 mg / L and a hydraulic retention time of 30 min. Water then flows from the top down into the first anaerobic packing zone 6, where the hydraulic retention time is 40 min. The effluent from the first anaerobic packing zone 6 enters the second aerobic packing zone 7 for secondary oxygenation, where the dissolved oxygen concentration is 4.5 mg / L and the hydraulic retention time is 30 min. The second anaerobic packing zone 8 has a hydraulic retention time of 40 min before the water flows out through the outlet. Multi-media biological ceramic particles are filled in the first aerobic packing zone 5 and the second aerobic packing zone 7, while modified porous microbial immobilized packing is filled in the first anaerobic packing zone 6 and the second anaerobic packing zone 8.

[0064] After the above combined treatment process, the chemical oxygen demand (COD) concentration was 30.5 mg / L, the ammonia nitrogen (NH3-N) concentration was 0.42 mg / L, and the total phosphorus (TP) concentration was 0.4 mg / L, all meeting or exceeding the national surface water Class V standard. The ecological landscape was restored, and the changes in water quality indicators before and after treatment are shown in the figure. Figure 4 As shown, it meets the acceptance requirements.

[0065] Thus far, the present disclosure has been described in detail with reference to the accompanying drawings. Those skilled in the art to which the disclosure pertains should be clearly aware of the present disclosure from the above description.

[0066] Note that the implementation not shown or described in the drawings or the specification is a form known to those skilled in the art, and is not described in detail. In addition, the above definition of each element is not limited to the various specific structures, shapes, or manners mentioned in the embodiments, and can be simply changed or replaced by those skilled in the art.

[0067] Of course, the present disclosure can also include other parts according to actual needs, since it is irrelevant to the innovation of the present disclosure, which will not be described here.

[0068] Similarly, it should be understood that, in order to simplify the present disclosure and help understand one or more of the various disclosed aspects, in the above description of the exemplary embodiments of the present disclosure, various features of the present disclosure are sometimes grouped together in a single embodiment, figure, or description thereof. However, the method of the present disclosure should not be interpreted as reflecting the intention that the claimed present disclosure requires more features than the features explicitly recorded in each claim. Rather, as reflected in the following claims, the disclosed aspects are based on less than all the features of the single embodiment disclosed above. Therefore, the claims following the specific embodiments are hereby expressly incorporated into the specific embodiments, in which each claim itself is a separate embodiment of the present disclosure.

[0069] In addition, in the drawings or description of the specification, similar or identical parts are denoted by the same reference numerals. The technical features in the exemplary embodiments of the specification can be freely combined to form new solutions without conflict, in addition, each claim can be a separate embodiment or the technical features in the claims can be combined to form a new embodiment, and in the drawings, the shape or thickness of the embodiment can be enlarged, and the simplification or convenience is indicated. Furthermore, the elements or implementations not shown or described in the drawings are forms known to those skilled in the art. In addition, although examples can provide parameters including specific values, it should be understood that the parameters do not necessarily equal the corresponding values, but can be approximately equal to the corresponding values within an acceptable error tolerance or design constraint.

[0070] Unless there is a technical obstacle or contradiction, the above various embodiments of the present disclosure can be freely combined to form additional embodiments, which are all within the protection scope of the present disclosure.

[0071] Although the present disclosure is illustrated with reference to the accompanying drawings, the embodiments disclosed in the drawings are intended to exemplify the preferred embodiments of the present disclosure and should not be understood as a limitation of the present disclosure. The dimensional proportions in the drawings are merely illustrative and should not be understood as a limitation of the present disclosure.

[0072] Although some embodiments of the general inventive concept have been shown and described, it is to be understood that changes can be made in embodiments without departing from the principles and spirit of the general inventive concept, the scope of which is to be circumscribed by the claims and their equivalents.

[0073] The specific embodiments described above are intended to exemplify the purpose, technical solutions and beneficial effects of the present disclosure, and it should be understood that the above description is only for specific embodiments of the present disclosure and is not intended to limit the present disclosure. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present disclosure should be included in the protection scope of the present disclosure.

Claims

1. A multi-stage stabilization pond and bio-baffle dam combined riverway restoration system, characterized by, The system adopts the combination of ecological multi-stage stabilization pond system and multi-medium biological overfall dam system to treat the river water in situ, wherein: In the direction of river water flow, the ecological multi-stage stabilization pond system is constructed before the multi-medium biological overfall dam system, the ecological multi-stage stabilization pond system is used to remove the main pollutants of the river water, and the multi-medium biological overfall dam system is used to remove nitrogen and phosphorus from the river water in depth; The ecological multi-stage stabilization pond system comprises, in sequence in the direction of river water flow, a flocculation and sedimentation zone (1), an ecological floating island zone (2) and a solar micro-nano aeration zone (3); The multi-medium biological overfall dam system adopts an overfall low dam system and a multi-medium biological filter bed, the multi-medium biological filter bed is constructed inside the overfall low dam system, in flood season, the water overflows the low dam through the overfall low dam system, and in non-flood season, the water is treated by secondary nitrification and denitrification through the multi-medium biological filter bed inside the overfall low dam system; the overfall low dam system adopts a bottom-up water inlet mode, the water inlets and outlets are staggered, ecological concrete revetments (9) are arranged on both sides of the overfall low dam system to prevent dam break; the multi-medium biological filter bed comprises, in sequence from the water inlet to the water outlet, a first aerobic filler zone (5), a first anaerobic filler zone (6), a second aerobic filler zone (7) and a second anaerobic filler zone (8), the water treated by the ecological multi-stage stabilization pond system enters the multi-medium biological filter bed from the first aerobic filler zone (5) and flows out of the multi-medium biological filter bed from the second anaerobic filler zone (8); The first aerobic filler zone (5) and the second aerobic filler zone (7) are filled with multi-medium biological ceramsite; the multi-medium biological ceramsite is prepared by the following method: Hangjin soil is mixed with sodium hydroxide and calcined at 550°C, the calcined product is stirred and filtered at 70°C, aluminum sulfate is added to the filtrate to adjust the silicon-aluminum atomic molar ratio, and a new type of artificial molecular sieve is prepared at 100-110°C, and the multi-medium biological ceramsite is prepared by using the molecular sieve as the raw material and fly ash, sawdust, clay and calcium carbonate as the auxiliary materials.

2. The multi-stage stabilization pond and biological overfall dam combined river restoration system according to claim 1, wherein The contaminated water flows into the ecological multi-stage stabilization pond system, enters the flocculation and sedimentation zone (1) first, the water is mixed with the flocculant in the flocculation and sedimentation zone (1), the suspended solids SS are reduced to below 20-30 mg / L, and the total phosphorus TP is reduced to 0.4-0.5 mg / L; The effluent of the flocculation and sedimentation zone (1) enters the ecological floating island zone (2), the chemical oxygen demand COD, ammonia nitrogen NH3-N and total phosphorus TP indexes of the water are reduced through the absorption of plant roots, the rapid biofilm formation of microorganisms on the biological carbon fiber and water purification carrier, and the adsorption of the biological carbon fiber and water purification carrier; Then the water body enters the solar micro-nano aeration area (3) to improve the dissolved oxygen (DO) of the water body, and the DO reaches 3-5 mg / L, the suspended solids (SS) decreases to 15-20 mg / L, the total phosphorus (TP) decreases to 0.3-0.4 mg / L, and the chemical oxygen demand (COD) decreases to 40-50 mg / L.

3. The multi-stage stabilization pond and bio-baffle dam combination river restoration system of claim 2, wherein, The flocculant comprises 100 mg / L of polyaluminum chloride (PAC) and 0.5 mg / L of polyacrylamide (PAM).

4. The multi-stage stabilization pond and biological overfall dam combined riverway restoration system according to claim 1, characterized in that, The first aerobic filler area (5) and the second aerobic filler area (7) are provided with solar aerators (10) to maintain the concentration of dissolved oxygen (DO); The first anaerobic filler area (6) and the second anaerobic filler area (8) are filled with modified porous microbial immobilized filler; The first aerobic filler area (5) and the first anaerobic filler area (6) are used to realize adsorption / primary cell oxidation / nitrification and adsorption / denitrification; The second aerobic filler area (7) and the second anaerobic filler area (8) are used to realize adsorption / primary cell oxidation / nitrification and adsorption / denitrification again, so as to realize the nitrification and denitrification processes simultaneously for the second time.

5. The multi-stage stabilization pond and bio-baffle dam combination river restoration system of claim 4, wherein, The modified porous microbial immobilized filler is prepared by the following method: The polyurethane is used as raw material, the cellulose natural carbon source material is added, the polyurethane macroporous microdegradable polymer is formed through foaming, granulation, opening and cross linking; the filler has a pore size of 2-7mm, a specific surface area of 33x10 4 m 2 / m 3 , a biomass of 25-35 g / L and a wet density of 1 g / cm 3 .

6. The multi-stage stabilization pond and bio-baffle dam combination river restoration system of claim 4, wherein, The first aerobic filler area (5), the first anaerobic filler area (6), the second aerobic filler area (7) and the second anaerobic filler area (8) are separated by partition walls (11), and two adjacent filler areas are communicated from top to bottom by a flow guide pipe, and a water distribution pipe is arranged at the bottom of the flow guide pipe to realize water inlet at the bottom of each filler area and water distribution; the aeration pipe of the aerobic area is located at the bottom, and water and air flow in the same direction; The water body enters the first aerobic filler area (5) from the water inlet (15), then enters the first anaerobic filler area (6) through the flow guide pipe (12) from top to bottom, the water body is fully contacted with the filler (14) through the bottom water distribution pipe (13), then passes through the second aerobic filler area (7) and the second anaerobic filler area (8) in turn, and is discharged from the water outlet (16).

7. The multi-stage stabilization pond and biological overfall dam combined riverway restoration system according to claim 6, characterized in that, The water body flows into the multi-medium biological overfall dam system, first enters the first aerobic filler area (5) from the bottom water inlet through the water distribution pipe, stays for 15-30 min, and is contacted with beneficial microorganisms in the first aerobic filler area (5) to perform nitrification reaction; the dissolved oxygen (DO) is controlled by the aeration machine in the aeration area, and the DO in the first aerobic filler area (5) is maintained at 3-5 mg / L; the beneficial microorganisms perform aerobic nitrification reaction and biological ceramsite primary cell oxidation reaction, most of the ammonia nitrogen is converted into nitrate nitrogen, and most of the organic matter and total phosphorus (TP) are removed; The water body enters the first anaerobic filler area (6) through the flow guide pipe from top to bottom, is fully contacted with the biological immobilized filler through the bottom water distribution pipe, stays for 20-40 min, and performs adsorption / denitrification in the first anaerobic filler area (6); most of the nitrate nitrogen and nitrite nitrogen are converted into nitrogen gas and removed; Then the water body enters the second aerobic filler area (7) through the diversion pipe for secondary oxygen dissolution, and the dissolved oxygen DO of the water body is increased to 3-5 mg / L, so that adsorption / nitrification / primary cell oxidation is realized again; Next, the water body enters the second anaerobic filler area (8) to realize adsorption / denitrification again, so that the suspended solids SS concentration is reduced to 10-15 mg / L, the chemical oxygen demand COD concentration is 30-40 mg / L, the NH3-N concentration is 0.2-0.5 mg / L, and the total phosphorus TP concentration is 0.3-0.4 mg / L, which meets the surface water V-class and above standards, and the effluent is discharged from the upper effluent outlet of the second anaerobic filler area (8).

8. A multi-stage stabilized pond and bio-detention dam combined river restoration method using the multi-stage stabilized pond and bio-detention dam combined river restoration system according to any one of claims 1 to 7, characterized by, The method comprises: The contaminated water body flows into the ecological combined multi-stage stable pond system, first enters the flocculation and sedimentation area (1), and the water body is mixed and reacted with the flocculating agent in the flocculation and sedimentation area (1), so that the suspended solids SS and total phosphorus TP in the water body are reduced; The effluent of the flocculation and sedimentation area (1) enters the ecological floating island area (2), and the chemical oxygen demand COD, ammonia nitrogen NH3-N and total phosphorus TP indexes of the water body are reduced through plant root absorption, rapid biofilm formation of microorganisms on biological carbon fiber and water purification carrier, and adsorption of biological carbon fiber and water purification carrier; The water body further passes through the solar micro-nano aeration area (3), and the dissolved oxygen DO of the water body is increased to 3-5 mg / L; the increase of the dissolved oxygen DO effectively reduces the chemical oxygen demand COD and NH3-N content in the water body; the nano bubbles have the functions of demulsification, flocculation and air flotation, and can effectively separate suspended solids SS, algae and oil; The water body flows into the multi-medium biological overflow dam system, first enters the first aerobic filler area (5) through the water distribution pipe from the dam inlet, and the hydraulic retention time is 20-60 min; the water body is contacted with beneficial microorganisms in the first aerobic filler area (5) to perform nitrification reaction, and the dissolved oxygen DO is controlled by an aerator; the dissolved oxygen DO in the first aerobic filler area (5) is maintained at 3-5 mg / L, and the beneficial microorganisms perform aerobic nitrification reaction and biological ceramic primary cell oxidation reaction to convert most of the ammonia nitrogen into nitrate nitrogen and remove organic matter and total phosphorus TP; The water body enters the first anaerobic filler area (6) through the top-down diversion pipe, and fully contacts with the microbial immobilized carrier through the bottom water distribution pipe; the hydraulic retention time is 30-60 min; adsorption / denitrification is performed in the first anaerobic filler area (6); most of the nitrate nitrogen and nitrite nitrogen is converted into nitrogen gas; in the water body with low carbon-nitrogen ratio C / N, the cellulose in the modified porous microbial immobilized filler can be hydrolyzed under the action of microorganisms, thereby releasing the required carbon source for denitrification. Next water flows into the second aerobic filler area (7) through the diversion pipe for secondary oxygen dissolving, and the oxygen dissolving amount DO of the water is increased to 3-5 mg / L, so as to realize adsorption / nitrification / primary cell oxidation again, enter the second anaerobic filler area (8), realize adsorption / denitrification again, and finally the indexes of suspended solids SS, chemical oxygen demand COD, ammonia nitrogen NH3-N, total amount of various forms of inorganic and organic nitrogen TN in water and total phosphorus TP are significantly reduced, and the effluent can be discharged up to the standard.

9. The multi-stage stabilization pond and bio-baffle dam combination river restoration method according to claim 8, characterized in that, Before the polluted water body flows into the ecological combined multi-stage stable pond system, further comprising: The high-efficiency nitrogen and phosphorus removal bacterial agent is put into the biological filter bed, and is cultured and trained for 5-7 days to realize the biofilm of microorganisms on the filler; in the case that the carbon-nitrogen ratio of the water body is low, the cellulose carbon source in the modified porous microbial immobilized filler in the first anaerobic filler area (6) and the second anaerobic filler area (8) is slowly hydrolyzed under the action of microorganisms to provide carbon source for anaerobic denitrification.

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