Sewage treatment system

Abstract

The utility model relates to the technical field of sewage treatment, in particular to a sewage treatment system which comprises a first wetland treatment unit, a second wetland treatment unit and a third wetland treatment unit, the first wetland treatment unit comprises a plurality of treatment assemblies arranged at intervals, the treatment assemblies are periodically filled with sewage, and the third wetland treatment unit comprises a third wetland treatment unit. The first wetland treatment unit is used for treating sewage through aerobic reaction to form first sewage, the second wetland treatment unit comprises a bent section, the bent section comprises a bent wall and an adsorption layer, the adsorption layer covers the bent wall, and the first sewage flows in the extending direction of the bent section; the dissolved oxygen concentration of the second wetland treatment unit is smaller than that of the first wetland treatment unit and larger than that of the third wetland treatment unit, and the third wetland treatment unit receives sewage treated by the second wetland treatment unit and conducts anaerobic reaction. The sewage treatment capacity is improved; meanwhile, the emission of greenhouse gases is reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of sewage treatment, in particular to a sewage treatment system. Background Art

[0002] Tidal flow artificial wetlands use the pore suction generated by the tidal movement of the saturated infiltration surface of the bed to absorb oxygen from the atmosphere into the bed, greatly improving the oxygen transfer and utilization rate in the wetland bed. Artificial wetlands are often used for sewage treatment in related technologies, but artificial wetlands produce a lot of greenhouse gases in low-oxygen or anoxic environments, resulting in excessive greenhouse gas emissions. Utility Model Content

[0003] The utility model aims to solve one of the technical problems in the related art to at least a certain extent. To this end, the embodiment of the utility model proposes a sewage treatment system, which can adjust the cycle time of the first wetland treatment unit and extend the residence time of sewage in the second wetland treatment unit, treat sewage in stages through artificial wetlands, improve sewage treatment capacity and reduce greenhouse gas emissions.

[0004] The sewage treatment system of the embodiment of the utility model includes: a first wetland treatment unit, the first wetland treatment unit is a tidal flow artificial wetland, the first wetland treatment unit includes a plurality of treatment components, the plurality of treatment components are arranged at intervals, the treatment components are periodically filled with sewage, and the sewage is treated by aerobic reaction to form first sewage; a second wetland treatment unit, the second wetland treatment unit is a subsurface flow artificial wetland, the dissolved oxygen concentration of the second wetland treatment unit is less than the dissolved oxygen concentration of the first wetland treatment unit, the second wetland treatment unit includes at least one bending section, the bending section includes a bending wall and an adsorption layer, the adsorption layer is covered on the bending wall, the first sewage flows along the extension direction of the bending section, and the adsorption layer can adsorb impurities in the first sewage; a third wetland treatment unit, the third wetland treatment unit is a horizontal artificial wetland, the dissolved oxygen concentration of the third wetland treatment unit is less than the dissolved oxygen concentration of the second wetland treatment unit, and the third wetland treatment unit is used to receive the sewage treated by the second wetland treatment unit for anaerobic reaction.

[0005] The sewage treatment system of the embodiment of the utility model can adjust the cycle time of the first wetland treatment unit and prolong the residence time of the sewage in the second wetland treatment unit, thereby improving the sewage treatment capacity and reducing the emission of greenhouse gases.

[0006] In some embodiments, the processing component includes a frame, a water inlet pipe and a water outlet pipe, the frame is filled with a first filler layer, one end of the water inlet pipe and one end of the water outlet pipe are both located in the first filler layer, one end of the water inlet pipe and one end of the water outlet pipe are spaced apart in the height direction of the frame, and the water outlet pipe is higher than the water inlet pipe.

[0007] In some embodiments, the frame is provided with through holes, and the first filler layer includes pebbles, modified clay and zeolite arranged in sequence from bottom to top.

[0008] In some embodiments, the second wetland treatment unit further includes a second filler layer, the second filler layer includes pebbles, modified slag and zeolite arranged in sequence from bottom to top, and the bending section is vertically arranged in the second filler layer to change the flow direction of the first sewage.

[0009] In some embodiments, the third wetland treatment unit includes a third packing layer, which includes pebbles, modified slag and zeolite arranged in sequence from bottom to top, and the height of the first packing layer is greater than or equal to the second packing layer, and the height of the second packing layer is greater than the third packing layer.

[0010] In some embodiments, the third wetland treatment unit includes a first outlet and a second outlet, the first outlet is connected to the first wetland treatment unit to form a first backflow, and the second outlet is used to discharge water treated by the third wetland treatment unit.

[0011] In some embodiments, the sewage treatment system also includes a membrane unit, the membrane unit having a first inlet, a fourth outlet and a fifth outlet, the third wetland treatment unit also includes a third outlet, the first inlet is connected to the third outlet, the fourth outlet is connected to the first wetland treatment unit to form a second backflow, and the fifth outlet is used to discharge water treated by the membrane unit.

[0012] In some embodiments, the first wetland treatment unit, the second wetland treatment unit and the third wetland treatment unit are each provided with a gas collection box and a dissolved oxygen meter, the gas collection box is used to collect greenhouse gases emitted by the wetland treatment unit, and the dissolved oxygen meter measures the dissolved oxygen concentration of the wetland to adjust the cycle time of the first wetland treatment unit.

[0013] In some embodiments, the sewage treatment system further includes a photocatalytic reactor, one end of the photocatalytic reactor is connected to the second wetland treatment unit, and the other end of the photocatalytic reactor is connected to the third wetland treatment unit.

[0014] In some embodiments, the sewage treatment system further includes a regulating tank, which is connected to the inlet end of the first wetland treatment unit, and is used to regulate the water volume and water quality of the sewage. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of a sewage treatment system according to an embodiment of the utility model.

[0016] Figure 2 It is a schematic diagram of the first wetland treatment unit of an embodiment of the utility model.

[0017] Figure 3 It is a schematic diagram of the second wetland treatment unit of an embodiment of the utility model.

[0018] Figure 4 It is a schematic diagram of the third wetland treatment unit of an embodiment of the present utility model.

[0019] Reference numerals:

[0020] The first wetland treatment unit 1, the treatment assembly 11, the frame 111, the water inlet pipe 112, the water outlet pipe 113, the first filler layer 114, the lifting ear 115,

[0021] The second wetland treatment unit 2, the bending section 21, the second filler layer 22, the wall 23,

[0022] The third wetland treatment unit 3, the third filler layer 31, the steel frame 32, the plants 33, the gas collection box 4, the water collection channel 5, the pebbles 6, the modified clay 7, the zeolite 8, and the modified slag 9. DETAILED DESCRIPTION

[0023] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to be used to explain the present invention, but cannot be understood as limiting the present invention.

[0024] The sewage treatment system of the embodiment of the utility model includes a first wetland treatment unit 1, a second wetland treatment unit 2 and a third wetland treatment unit 3. The first wetland treatment unit 1 is a tidal flow artificial wetland, and the first wetland treatment unit 1 includes a plurality of treatment components 11, and the plurality of treatment components 11 are arranged at intervals. The treatment components 11 are periodically filled with sewage, and the sewage is treated by aerobic reaction to form first sewage. The second wetland treatment unit 2 is a submerged flow artificial wetland, and the dissolved oxygen concentration of the second wetland treatment unit 2 is less than the dissolved oxygen concentration of the first wetland treatment unit 1. The second wetland treatment unit 2 includes at least one bending section 21, and the bending section 21 includes a bending wall and an adsorption layer. The adsorption layer is covered on the bending wall, and the first sewage flows along the extension direction of the bending section 21. The adsorption layer can adsorb impurities in the first sewage. The third wetland treatment unit 3 is a horizontal artificial wetland, and the dissolved oxygen concentration of the third wetland treatment unit 3 is less than the dissolved oxygen concentration of the second wetland treatment unit 2. The third wetland treatment unit 3 is used to receive the sewage treated by the second wetland treatment unit 2 for anaerobic reaction.

[0025] It should be noted that the tidal flow artificial wetland uses the pore suction generated by the tidal operation of the saturated infiltration surface of the bed to absorb oxygen from the atmosphere into the bed, thereby significantly improving the oxygen transfer and utilization rate in the wetland bed, thereby enhancing the wetland's purification effect on pollutants. The sewage treatment system of this embodiment can be used to remove pollutants from tail water in industrial parks.

[0026] Specifically, Figure 1-Figure 3 As shown, the tidal flow artificial wetland alternately fills and empties the wetland bed with sewage, which increases the oxygenation capacity of the tidal flow artificial wetland and forms an efficient oxygen-rich zone. Multiple treatment components 11 are arranged at intervals to form the wetland bed. The interval arrangement of the multiple treatment components 11 is beneficial to the uniform distribution and flow of sewage water, and is also beneficial to the transmission and diffusion of oxygen.

[0027] The first wetland treatment unit 1 and the second wetland treatment unit 2 are arranged at intervals in the left-right direction. The first sewage treated by the first wetland treatment unit 1 is transmitted to the second wetland treatment unit 2 through the water collection channel 5. Since the dissolved oxygen concentration of the second wetland treatment unit 2 is lower than that of the first wetland treatment unit 1, the first sewage can continue to react in the second wetland treatment unit 2. Since a bending section 21 is provided in the second wetland treatment unit 2, the bending section 21 allows the first sewage to flow along the extension direction of the bending section 21 first, and then changes the water flow direction of the first sewage under the action of the bending section 21. The setting of the bending section 21 can increase the water retention time, thereby increasing the reaction time between the first sewage and the second wetland treatment unit 2, thereby improving the denitrification capacity of the second wetland treatment unit 2.

[0028] After being fully reacted in the second wetland treatment unit 2, the first sewage flows to the third wetland treatment unit 3, and mainly undergoes anaerobic reaction in the third wetland treatment unit 3. Through the combination of aerobic reaction and anaerobic reaction, the organic matter and nitrogen elements in the sewage can be better removed, thereby improving the effect and quality of sewage treatment.

[0029] It is understandable that the greenhouse gases emitted by wetland treatment units are mainly methane and nitrous oxide, while methane is the main product under anaerobic conditions, and nitrous oxide is produced during nitrification and denitrification. By controlling and adjusting the concentration of dissolved oxygen in tidal flow artificial wetlands, greenhouse gas emissions during aerobic and anoxic reactions can be reduced. The specific setting parameters need to be adjusted according to the water quality and quantity of the sewage.

[0030] For example, the hydraulic load of the first wetland treatment unit 1 is 200-300L / ㎡.d, and the residence time is 2-3d; the hydraulic load of the second wetland treatment unit 2 is 150-250L / ㎡.d, and the residence time is 2-3d; the hydraulic load of the third wetland treatment unit 3 is less than or equal to 100L / ㎡.d, and the residence time is 0.5d.

[0031] The sewage mainly undergoes aerobic reaction in the first wetland treatment unit 1, but there is also some anaerobic reaction. The sewage is treated by aerobic reaction to form the first sewage. The first sewage mainly undergoes aerobic reaction in the second wetland treatment unit 2, that is, the first sewage undergoes both aerobic reaction and anaerobic reaction in the second wetland treatment unit 2.

[0032] The sewage treatment system of the embodiment of the utility model first passes the sewage into the first wetland treatment unit 1 for aerobic reaction to remove organic matter and part of ammonia nitrogen in the sewage, and then transmits the first sewage to the second wetland treatment unit 2 for secondary aerobic reaction. The first wetland treatment unit 1 and the second wetland treatment unit 2 form a composite artificial wetland to create better conditions for the anoxic reaction of the third wetland treatment unit 3, and then the sewage treated by the second wetland treatment unit 2 is transmitted to the third wetland treatment unit 3 for anaerobic reaction. By adjusting the cycle time of the tidal flow artificial wetland, the adjustment of different concentrations of dissolved oxygen in the tidal flow artificial wetland is achieved, and the aerobic reaction and the anaerobic reaction are carried out to achieve tiered sewage treatment by artificial wetlands, which can more effectively remove organic matter and nitrogen elements in the sewage, improve the treatment capacity of the wetland treatment unit and reduce greenhouse gas emissions.

[0033] Furthermore, in this embodiment, three-stage wetland treatment units are set up. Based on the concentration gradient of dissolved oxygen, the first wetland treatment unit 1 adopts a water filling reaction-discharge idle mode. The oxygen filling capacity is 8-10 times higher than that of a general wetland, forming an oxygen-rich zone. Combined with the relatively anoxic zone of the second wetland treatment unit 2 and the anaerobic reaction of the third wetland treatment unit 3, a composite wetland is constructed to achieve a biochemical treatment effect similar to A / O, optimize the sewage treatment process, and reduce greenhouse gas emissions.

[0034] In some embodiments, the processing component 11 includes a frame 111, an inlet pipe 112 and an outlet pipe 113. The frame 111 is filled with a first filler layer 114. One end of the inlet pipe 112 and one end of the outlet pipe 113 are both located in the first filler layer 114. One end of the inlet pipe 112 and one end of the outlet pipe 113 are spaced apart in the height direction of the frame 111, and the outlet pipe 113 is higher than the inlet pipe 112.

[0035] Specifically, Figure 2 As shown, the treatment components 11 are arranged in a matrix, and the treatment components 11 are alternately filled with sewage and emptied of sewage. The lower ends of the water inlet pipe 112 and the water outlet pipe 113 are both located in the first packing layer 114, so that the sewage enters the first packing layer 114 from the bottom and flows out of the first packing layer 114 from the top, which makes it easier for the first packing layer 114 to absorb and filter pollutants in the sewage, thereby improving the treatment capacity of the first wetland treatment unit 1.

[0036] Optionally, the treatment component 11 further includes an anti-seepage layer and a lifting ear 115. The anti-seepage layer is arranged below the frame 111. The anti-seepage layer is a HDPE film to prevent sewage from penetrating downwards. The lifting ear 115 is arranged above the frame 111 for easy installation.

[0037] For example, the material of the frame 111 is polyethylene. The size of the frame 111 is 1m×1m×1.2m, and the interval size between two adjacent treatment components 11 is 1m-1.5m, which is convenient for the flow of sewage and the transmission of oxygen.

[0038] In some embodiments, the frame 111 is provided with through holes, and the first filler layer 114 includes pebbles 6, modified clay 7 and zeolite 8 arranged in sequence from bottom to top.

[0039] Specifically, Figure 2 As shown, the water outlet end of the water inlet pipe 112 is located in the pebbles 6, the water inlet end of the water outlet pipe 113 is located in the zeolite 8, and the height ratio of the pebbles 6, the modified clay 7 and the zeolite 8 in the first packing layer 114 is 1:2:1. The particle size of the first packing layer 114 increases gradually from bottom to top, the lower layer can absorb and filter larger molecular pollutants, and the upper layer can absorb and filter smaller pollutants.

[0040] The size of the through hole in this embodiment is 0.2-0.3 cm. By limiting the size of the through hole, the gap between the first packing layers 114 is further limited, so that there is a certain looseness between the first packing layers 114, which can better utilize the specific surface area of ​​the first packing layer 114 and improve the sewage treatment capacity of the first packing layer 114.

[0041] In some embodiments, the second wetland treatment unit 2 also includes a second packing layer 22, which includes pebbles 6, modified slag 9 and zeolite 8 arranged in sequence from bottom to top, and the bending section 21 is vertically arranged in the second packing layer 22 to change the flow direction of the first sewage.

[0042] Specifically, Figure 3 As shown, the second wetland treatment unit 2 also includes a wall 23, and a second filler layer 22 is filled between the wall 23 and the bending section 21. The height ratio of pebbles 6, modified slag 9 and zeolite 8 in the second filler layer 22 is 0.5:0.25:0.25m.

[0043] In this embodiment, the second wetland treatment unit 2 includes two bending sections 21, which are arranged in parallel and extend in the front-to-back direction. The two bending sections 21 are arranged at intervals in the left-to-right direction. A gap is provided between the front end of the bending section 21 on the left and the front wall 23, and a gap is provided between the rear end of the bending section 21 on the right and the rear wall 23, so that the first sewage flows forward along the bending section 21 on the left, and flows to the bending section 21 on the right under the obstruction of the front wall 23, flows backward along the bending section 21 on the right, and then flows to the wall 23 on the right under the obstruction of the rear wall 23 until it flows out of the second wetland treatment unit 2. The bending section 21 is provided to form a circuitous flow channel, reduce the existence of dead corners, and extend the reaction time between the first sewage and the second wetland treatment unit 2. In addition, the bending section 21 also includes an adsorption layer. The provision of the adsorption layer can increase the processing capacity of the second wetland treatment unit 2, thereby reducing the emission of greenhouse gases.

[0044] In some embodiments, the third wetland treatment unit 3 includes a third packing layer 31, the third packing layer 31 includes pebbles 6, modified slag 9 and zeolite 8 arranged in sequence from bottom to top, and the height of the first packing layer 114 is greater than or equal to the second packing layer 22, and the height of the second packing layer 22 is greater than the third packing layer 31.

[0045] Specifically, Figure 4 As shown, the sewage treated by the second wetland treatment unit 2 enters the third treatment unit for anaerobic treatment. The third wetland treatment unit 3 includes a steel frame 32 and a third filling layer. The third filling layer is filled in the space surrounded by the steel frame 32. The height ratio of pebbles 6, modified slag 9 and zeolite 8 in the third filling layer 31 is 0.3:0.2:0.2m.

[0046] Optionally, plants 33 are planted on the third wetland treatment unit 3 to increase the wetland vegetation coverage area, thereby improving the absorption capacity of the wetland plants 33, increasing the ornamental value and reducing greenhouse gas emissions.

[0047] For example, the height of the first packing layer 114 is between 1.5 and 2 m, the height of the second packing layer 22 is the same as the height of the first packing layer 114, or the height of the second packing layer 22 is between 1 and 1.5 m, and the height of the third packing layer 31 is between 0.5 and 0.8 m.

[0048] The sewage treatment system of the embodiment of the utility model forms a gravity flow between different wetland treatment units by setting a first wetland treatment unit 1, a second wetland treatment unit 2 and a third wetland treatment unit 3 with decreasing heights, which can reduce the setting of power devices and save energy.

[0049] In some embodiments, the third wetland treatment unit 3 includes a first outlet and a second outlet, the first outlet is connected to the first wetland treatment unit 1 to form a first reflux, and the second outlet is used to discharge water treated by the third wetland treatment unit 3 .

[0050] Specifically, Figure 1 As shown, the water treated by the third wetland treatment unit 3 can be discharged directly or flow back to the first wetland treatment unit 1 for further treatment. The water treated by the third wetland treatment unit 3 needs to be selected according to actual conditions. If the water treated by the third wetland treatment unit 3 reaches surface water Class IV or above, it can be discharged directly. If the water treated by the third wetland treatment unit 3 does not reach surface water Class IV or above, it needs to flow back to the first wetland treatment unit 1 for further treatment to ensure that the water treated by the sewage treatment system can meet the discharge requirements.

[0051] In some embodiments, the sewage treatment system also includes a membrane unit, the membrane unit has a first inlet, a fourth outlet and a fifth outlet, the third wetland treatment unit 3 also includes a third outlet, the first inlet is connected to the third outlet, the fourth outlet is connected to the first wetland treatment unit 1 to form a second backflow, and the fifth outlet is used to discharge water treated by the membrane unit.

[0052] Specifically, the water treated by the third treatment unit can flow to the membrane unit through the third outlet, and whether to enter the membrane unit is determined according to actual water demand, for example, as landscape water replenishment, or when the reclaimed water is reused, it needs to be treated by the membrane unit before reuse.

[0053] The second reflux is determined according to the selection of the membrane of the membrane unit. If the water treated by the membrane unit does not meet the requirements for recycled water reuse, it can be returned to the first wetland treatment unit 1 through the fourth outlet for reprocessing to ensure that the water quality after treatment by the sewage treatment system meets the standards. If the water treated by the membrane unit meets the requirements for recycled water reuse, it can be directly reused.

[0054] For example, the membrane unit uses microfiltration, ultrafiltration and reverse osmosis. The pore size of the microfiltration membrane can be 1μm-3μm, the pore size of the ultrafiltration membrane can be 0.05-0.1μm, and the reverse osmosis membrane can be 0.1nm, which can effectively remove heavy metals. The reverse osmosis concentrated water of the second reflux of the membrane unit is returned to the first wetland treatment unit 1, and the reverse osmosis recovery rate can be adjusted according to relevant operation data.

[0055] In some embodiments, the first wetland treatment unit 1, the second wetland treatment unit 2 and the third wetland treatment unit 3 are each provided with a gas collection box 4 and a dissolved oxygen meter (not shown in the figure). The gas collection box 4 is used to collect greenhouse gases emitted by the wetland treatment units, and the dissolved oxygen meter measures the dissolved oxygen concentration of the wetland to adjust the cycle time of the first wetland treatment unit 1.

[0056] Specifically, the greenhouse gases emitted by the wetland mainly include methane and nitrous oxide. The greenhouse gases emitted by each wetland treatment unit are collected by the gas collection box 4, and the concentration of the collected greenhouse gases is detected. The concentration of dissolved oxygen in each wetland treatment unit can reflect the sewage treatment capacity and treatment effect of each wetland treatment unit. The cycle time of the first wetland treatment unit 1 is adjusted by combining the concentration of greenhouse gases with the concentration of dissolved oxygen to improve the treatment capacity and effect of each wetland treatment unit.

[0057] For example, in the monitoring of the first wetland treatment unit 1 and the second wetland treatment unit 2, the CH4 concentration was 0.5-5.2 mg / m 2 *h, N2O concentration is 0.005-0.410mg / m 2 *h; In the monitoring of the third wetland treatment unit 3, the CH4 concentration was 0.05-16.8 mg / m 2 *h, N2O concentration is 0.018-0.763mg / m 2 *h, it indicates that the greenhouse gas emissions of each wetland treatment unit are within the required range. If the methane and nitrous oxide emissions of the first wetland treatment unit 1 and / or the second wetland treatment unit 2 and / or the third wetland treatment unit 3 exceed the above range, it is necessary to adjust the cycle time of the first wetland treatment unit 1 to adjust the treatment capacity of each wetland treatment unit, improve the sewage treatment capacity, and keep the greenhouse gas emissions within the required range.

[0058] The embodiment of the utility model detects the emission amount and emission concentration of greenhouse gases, and then adjusts the oxygen exposure frequency and the reflow ratio of the first wetland treatment unit 1, so as to achieve the effect of improving pollutant removal and reducing carbon emissions.

[0059] In some embodiments, the sewage treatment system further includes a photocatalytic reactor, one end of the photocatalytic reactor is connected to the second wetland treatment unit 2 , and the other end of the photocatalytic reactor is connected to the third wetland treatment unit 3 .

[0060] Specifically, the photocatalytic reactor can treat the difficult-to-degrade pollutants by the first wetland treatment unit 1 and the second wetland treatment unit 2, remove the larger pollutants in the sewage by the first wetland treatment unit 1 and the second wetland treatment unit 2, and then remove the smaller pollutants in the sewage by the photocatalytic reactor, thereby improving the sewage treatment capacity.

[0061] For example, the photocatalytic reactor is intermittent and uses modified titanium dioxide as a photocatalyst. By adjusting the photocatalytic and adsorption ratio according to the water quality of the sewage, it can efficiently remove difficult-to-degrade organic matter in the tail water of the industrial park. At the same time, it can decompose difficult-to-remove large-molecule organic matter into small-molecule organic matter, thereby improving the biochemical effect of subsequent processes.

[0062] Optionally, the sewage treated by the photocatalytic reactor flows to the third wetland treatment unit 3, and the third wetland treatment unit 3 can treat the photocatalyst that may leak out during the photocatalytic process to ensure the sewage treatment effect.

[0063] The sewage treatment system of the embodiment of the utility model comprehensively considers the characteristics of the industrial park tail water pollutants that are diverse and complex. By setting up a three-level artificial wetland and coupling it with a photocatalytic reactor, not only can the difficult-to-degrade organic matter in the tail water be efficiently removed, but also by planting plants 33 on the third wetland treatment unit 3, the park landscape effect can be improved. At the same time, a membrane unit is set after the third wetland treatment unit 3, and different process selections can be made according to the needs of the park water system, so that the effluent of the sewage treatment system can meet the surface water Class IV or above emission standards, and can also be directly used for industrial water or reclaimed water reuse in the park, achieving the demand for zero discharge of sewage in the park.

[0064] For example, the sewage inflow is in the order of the first wetland treatment unit 1, the second wetland treatment unit 2, the photocatalytic reactor, the third wetland treatment unit 3 and the membrane unit. The sewage inflow volume is 1000m 3 / d, COD is 60mg / L, BOD5 is 20mg / L, SS is 20mg / L, ammonia nitrogen is 15mg / L, TN is 20mg / L, TP is 1mg / L, and cadmium is 1.5mg / L. Among them, COD refers to the amount of reducing substances that need to be oxidized in the water sample measured by chemical methods. BOD5 refers to the amount of dissolved oxygen consumed by microbial metabolism within 5 days of measurement, which is an important indicator to indirectly indicate the degree of organic pollution in the water body. SS refers to the concentration of activated sludge in the mixed liquor, and ammonia nitrogen is a form of nitrogen in the water body, which is an important pollutant for eutrophication of water bodies and environmental pollution. TN represents the total amount of various forms of inorganic and organic nitrogen in water during sewage treatment. TP represents total phosphorus, which is an important indicator for evaluating the phosphorus content in wastewater.

[0065] The filling reaction-discharge idle ratio of the first wetland treatment unit 1 is 4:4 hours. The dissolved oxygen concentration detected by the dissolved oxygen meters of the first wetland treatment unit 1 and the second wetland treatment unit 2 is 3.5 mg / L. The CH4 and N2O collected by the gas collection box 4 have a volume of 4m 3 and 5m 3 The dissolved oxygen concentration detected by the dissolved oxygen meter of the third wetland treatment unit 3 is 1.2 mg / L, and the CH4 and N2O collected by the gas collection box have a volume of 7m 3 and 8.5m 3 The reflux ratio of the membrane unit is 70%, and the effluent standards are COD 15mg / L, BOD5 10mg / L, SS 3.5mg / L, ammonia nitrogen 6mg / L, TN 1.2mg / L, TP 0.2mg / L, and cadmium 0.02mg / L.

[0066] In some embodiments, the sewage treatment system further includes a regulating tank, which is connected to the inlet end of the first wetland treatment unit 1 and is used to regulate the water volume and water quality of the sewage.

[0067] Specifically, by setting a regulating tank before the first wetland treatment unit 1, the water volume and water quality of the sewage are regulated to improve the uniformity of the sewage.

[0068] The present embodiment also proposes a sewage treatment method, which includes periodically filling a first wetland treatment unit with sewage for aerobic reaction to form first sewage, wherein the first wetland treatment unit is a tidal flow artificial wetland; allowing the first sewage to flow along the extension direction of the bending section of the second wetland treatment unit to adsorb impurities in the first sewage, wherein the second wetland treatment unit is a submerged flow artificial wetland, the second wetland treatment unit includes at least one bending section, the bending section includes a bending wall and an adsorption layer, the adsorption layer is covered on the bending wall, and the dissolved oxygen concentration of the second wetland treatment unit is less than the dissolved oxygen concentration of the first wetland treatment unit; transmitting the sewage treated by the second wetland treatment unit to a third wetland treatment unit for anaerobic reaction, wherein the third wetland treatment unit is a horizontal artificial wetland, and the dissolved oxygen concentration of the third wetland treatment unit is less than the dissolved oxygen concentration of the second wetland treatment unit.

[0069] The sewage treatment method of this embodiment first passes the sewage into the first wetland treatment unit for aerobic reaction to remove organic matter and part of ammonia nitrogen in the sewage, and then transmits the first sewage to the second wetland treatment unit for secondary aerobic reaction. The first wetland treatment unit and the second wetland treatment unit form a composite artificial wetland to create better conditions for the anoxic reaction of the third wetland treatment unit. The sewage treated by the second wetland treatment unit is then transmitted to the third wetland treatment unit for anaerobic reaction. By adjusting the cycle time of the tidal flow artificial wetland, the adjustment of different concentrations of dissolved oxygen in the tidal flow artificial wetland is achieved. In conjunction with the aerobic reaction and the anaerobic reaction, the artificial wetland is used to treat sewage in a cascade manner, which can more effectively remove organic matter and nitrogen elements in the sewage, improve the treatment capacity of the wetland treatment unit, and reduce greenhouse gas emissions.

[0070] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0071] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of the present utility model, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0072] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0073] In the present utility model, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" and "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0074] In the present utility model, the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" etc. mean that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present utility model. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0075] It is understandable that the above embodiments are exemplary and cannot be construed as limiting the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A sewage treatment system, characterized in that: include: A first wetland treatment unit, wherein the first wetland treatment unit is a tidal flow artificial wetland, and the first wetland treatment unit comprises a plurality of treatment components, wherein the plurality of treatment components are arranged at intervals, and the treatment components are periodically filled with sewage, and the sewage is treated by aerobic reaction to form first sewage; a second wetland treatment unit, wherein the second wetland treatment unit is a subsurface artificial wetland, wherein the dissolved oxygen concentration of the second wetland treatment unit is lower than that of the first wetland treatment unit, wherein the second wetland treatment unit comprises at least one bending section, wherein the bending section comprises a bending wall and an adsorption layer, wherein the adsorption layer is covered on the bending wall, wherein the first sewage flows along an extension direction of the bending section, and wherein the adsorption layer can adsorb impurities in the first sewage; The third wetland treatment unit is a horizontal artificial wetland, the dissolved oxygen concentration of the third wetland treatment unit is lower than the dissolved oxygen concentration of the second wetland treatment unit, and the third wetland treatment unit is used to receive the sewage treated by the second wetland treatment unit for anaerobic reaction.

2. The sewage treatment system according to claim 1, characterized in that: The processing component includes a frame, a water inlet pipe and a water outlet pipe. The frame is filled with a first filler layer. One end of the water inlet pipe and one end of the water outlet pipe are both located in the first filler layer. One end of the water inlet pipe and one end of the water outlet pipe are spaced apart in the height direction of the frame, and the water outlet pipe is higher than the water inlet pipe.

3. The sewage treatment system according to claim 2, characterized in that: The frame is provided with through holes, and the first filler layer comprises pebbles, modified clay and zeolite arranged in sequence from bottom to top.

4. The sewage treatment system according to claim 2, characterized in that: The second wetland treatment unit also includes a second filler layer, which includes pebbles, modified slag and zeolite arranged in sequence from bottom to top, and the bending section is vertically arranged in the second filler layer to change the flow direction of the first sewage.

5. The sewage treatment system according to claim 4, characterized in that: The third wetland treatment unit includes a third filler layer, which includes pebbles, modified slag and zeolite arranged in sequence from bottom to top, and the height of the first filler layer is greater than or equal to the second filler layer, and the height of the second filler layer is greater than the third filler layer.

6. The sewage treatment system according to claim 1, characterized in that: The third wetland treatment unit includes a first outlet and a second outlet, the first outlet is connected to the first wetland treatment unit to form a first backflow, and the second outlet is used to discharge water treated by the third wetland treatment unit.

7. The sewage treatment system according to claim 6, characterized in that: It also includes a membrane unit, which has a first inlet, a fourth outlet and a fifth outlet. The third wetland treatment unit also includes a third outlet. The first inlet is connected to the third outlet, the fourth outlet is connected to the first wetland treatment unit to form a second reflux, and the fifth outlet is used to discharge water treated by the membrane unit.

8. The sewage treatment system according to claim 7, characterized in that: The first wetland treatment unit, the second wetland treatment unit and the third wetland treatment unit are each provided with a gas collection box and a dissolved oxygen meter. The gas collection box is used to collect greenhouse gases emitted by the wetland treatment unit, and the dissolved oxygen meter measures the dissolved oxygen concentration of the wetland to adjust the cycle time of the first wetland treatment unit.

9. The sewage treatment system according to claim 1, characterized in that: It also includes a photocatalytic reactor, one end of which is connected to the second wetland treatment unit, and the other end of which is connected to the third wetland treatment unit.

10. The sewage treatment system according to any one of claims 1 to 9, characterized in that: It also includes a regulating tank, which is connected to the inlet end of the first wetland treatment unit and is used to regulate the water volume and water quality of sewage.

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