An artificial wetland system with wastewater purification function

Abstract

This application relates to an constructed wetland system with wastewater purification function. This application falls within the field of water purification technology. The technical problem this application aims to solve is: to provide an constructed wetland system with wastewater purification function. The technical solution adopted in this application is: a constructed wetland system with wastewater purification function, comprising: a sedimentation tank, into which polluted river water is introduced, capable of settling particulate matter in the polluted river water; at least one bioreactor, located at the output end of the sedimentation tank, capable of performing primary purification treatment on the polluted river water after sedimentation, through physical filtration and biodegradation; and an constructed wetland structure, located at the output end of the bioreactor, capable of performing secondary purification treatment on the polluted river water after primary purification by the bioreactor, through media filtration and plant absorption of some residual pollutants in the polluted river water.

Description

Technical Field

[0001] This utility model relates to the field of water purification technology, and in particular to an artificial wetland system with sewage purification function. Background Technology

[0002] While traditional wastewater treatment facilities have alleviated water pollution pressure to some extent, they still have the following prominent problems: (1) Low treatment efficiency and difficulty in dealing with complex pollutants: Existing wastewater treatment processes have limited efficiency in removing complex pollutants such as nitrogen, phosphorus, and organic matter, making it difficult to meet increasingly stringent emission standards.

[0003] (2) High operating costs and high energy consumption: Many centralized sewage treatment plants rely on chemical agents, which require large investment in construction and are complex to operate and maintain.

[0004] (3) Weak ecological restoration capacity: Traditional treatment methods focus on pollutant removal and lack the function of restoring and rebuilding the aquatic ecosystem, making it difficult to achieve the goal of "pollution control + ecology" coordinated governance.

[0005] Against this backdrop, constructed wetland systems that combine natural treatment technologies with modern engineering techniques are gaining increasing attention. These systems not only effectively remove various pollutants but also offer excellent landscape effects and ecological benefits, making them particularly suitable for treating lightly to moderately polluted river water or domestic sewage from small communities.

[0006] Therefore, there is a need for an artificial wetland system with wastewater purification function to solve technical bottlenecks such as low purification efficiency, high operating costs, and insufficient ecological benefits. Summary of the Invention

[0007] The technical problem to be solved by this utility model is to provide an artificial wetland system with sewage purification function to address the above-mentioned problems.

[0008] The technical solution adopted by this utility model is: an artificial wetland system with sewage purification function, comprising: A sedimentation tank, with polluted river water introduced at its input end, is able to settle particulate matter in the polluted river water; At least one bioreactor, located at the output end of the grit chamber, is capable of performing a primary purification treatment on the polluted river water after sedimentation in the grit chamber, thereby physically filtering and biodegrading the polluted river water. The constructed wetland structure, located at the output end of the bioreactor, can perform secondary purification of polluted river water after the primary purification treatment by the bioreactor, using media filtration and plant absorption to remove some of the pollutants remaining in the polluted river water.

[0009] By integrating sedimentation tanks, bioreactors, and constructed wetland structures, the sedimentation tanks initially remove large particulate pollutants, the bioreactors achieve efficient filtration and microbial degradation, and the constructed wetlands further remove residual pollutants through plant absorption and rhizosphere microbial action, thereby achieving a synergistic effect of physical, biological, and plant-based multi-level purification mechanisms.

[0010] In some embodiments, the bioreactor includes a reactor body and a multi-layer filter media layer. The multi-layer filter media layer is stacked inside the reactor body. A first inlet is provided at the top of the side wall on one side of the reactor body, and an outlet is provided at the bottom of the side wall on the other side of the reactor body, so that polluted water flows from the top of the multi-layer filter media layer to its bottom. The multi-layer filter media layer can remove some of the pollutants in the polluted water.

[0011] In some embodiments, the multilayer filter media layer comprises, from bottom to top, a first granular layer, a biostone layer, a second granular layer, and a porous mineral material layer. The first granular layer comprises zeolite and biochar, which can cultivate aerobic bacteria to decompose pollutants. The biostone layer comprises ceramic particles, which can attach microorganisms to purify polluted river water. The second granular layer comprises gravel. The porous mineral material layer comprises a mixture of zeolite and olivine in a 1:1 volume ratio, which can attach microorganisms to purify polluted river water.

[0012] In some embodiments, the biochar has a particle size of 20 mm to 35 mm, the ceramic particles have a particle size of 15 mm to 50 mm, the gravel has a particle size of 2 mm to 5 mm, and the mixture of zeolite and olivine has a particle size of 10 mm to 30 mm. The thickness ratio of the first granular layer, the bio-rock layer, the second granular layer, and the porous mineral material layer is 1:3:4:2.

[0013] In some embodiments, a water collection tank is provided between adjacent bioreactors, the outlet at the bottom of the bioreactor is connected to the water collection tank, the top of the side wall of the water collection tank is provided with a first inlet that can be connected to the next stage bioreactor, and the top of the side wall of the final stage water collection tank is provided with a water guide pipe that can be connected to the artificial wetland structure, so that the water treated by the previous stage bioreactor is collected in the water collection tank and then overflows into the next stage bioreactor.

[0014] In some embodiments, the bottom of the bioreactor is further provided with an air injection device, which is connected to an external air source. The output end of the air injection device is located below the multi-layer filter media layer, and can inject air into the multi-layer filter media layer.

[0015] In some embodiments, the bottom of the bioreactor is also provided with a sludge collection device, which can collect the sludge generated by the polluted river water flowing through the multi-layer filter media layer. The bottom of the sludge collection device is connected to a sludge discharge pipe, which can discharge the collected sludge.

[0016] In some embodiments, the constructed wetland structure includes an inverted trapezoidal box and internal packing material. The top of the box is provided with a second inlet that can connect to the output end of the bioreactor, so that the water after the bioreactor has been purified once is introduced into the box through the second inlet. The box is provided with layered stacked internal packing material, and the water flowing through the internal packing material can be filtered step by step. Aquatic plants are provided on the top of the internal packing material.

[0017] In some embodiments, the internal filler material includes, from bottom to top, a pebble layer, a gravel layer, a zeolite layer, a ceramic particle layer, and a planting layer. A porous pipe is embedded in the pebble layer, and geotextile is laid between each medium layer. The thickness ratio of the pebble layer, gravel layer, zeolite layer, ceramic particle layer, and planting layer is 2:2:1:2:3. The aquatic plants include reeds and calamus.

[0018] In some embodiments, the porous pipe is connected to a water storage tank via a first pipe, and the porous pipe is connected to a river via a second pipe, so that the water inside the tank can be stored in an outlet tank via the first pipe or discharged into the river via the second pipe after being filtered by the internal packing material.

[0019] The beneficial effects of this utility model are: 1. By combining sedimentation tanks, bioreactors, and constructed wetland structures, a multi-stage purification system is formed. First, the sedimentation tank initially removes large particulate pollutants. Then, the bioreactor uses multiple media for efficient filtration and microbial degradation. Finally, the constructed wetland structure further removes residual pollutants through plant absorption, rhizosphere microbial activity, and adsorption by packing materials. This synergistic effect allows for the deep removal of multiple pollutants. Relying on gravity flow, natural biodegradation, and plant purification, it reduces the need for chemical inputs and simplifies operation and maintenance. Introducing a plant ecosystem into the constructed wetland structure allows aquatic plants to not only absorb pollutants but also improve the aquatic ecological environment, thus giving the constructed wetland structure both aesthetic value and enhanced ecological restoration capabilities. Attached Figure Description

[0020] Figure 1 This is a structural diagram of this application.

[0021] Figure 2 This is a cross-sectional view of the bioreactor in this application.

[0022] Figure 3 This is a schematic diagram of the constructed wetland structure in this application.

[0023] Figure 4 This is a schematic diagram showing the approximate flow direction of the water in this application.

[0024] Figure 5 yes Figure 4 A schematic diagram of the cross section along the AA direction.

[0025] Explanation of reference numerals in the attached figures: 100. Sedimentation tank; 110. Polluted river water; 200. Bioreactor; 210. Multi-layer filter media layer; 211. First granular layer; 212. Bio-rock layer; 213. Second granular layer; 214. Porous mineral material layer; 215. Air injection device; 216. Sludge discharge pipe; 220. Water collection tank; 230. First inlet; 240. Outlet; 250. Water guide pipe; 300. Constructed wetland structure; 310. Internal filler; 311. Pebble layer; 312. Gravel layer; 313. Zeolite layer; 314. Ceramic particle layer; 315. Planting layer; 316. Geotextile; 320. Box body; 330. Second inlet; 350. Porous pipe; 351. Water storage tank; 360. Aquatic plants.

[0026] This specification includes references to "one embodiment" or "implementation". The use of the phrase "in one embodiment" or "in an embodiment" does not necessarily refer to the same embodiment. Specific features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure.

[0027] The term "comprising" is open-ended. As used in the appended claims, it does not exclude additional structures or steps.

[0028] "First," "second," etc. As used in this article, these terms serve as labels for the nouns preceding them and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.). Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solution of the present invention will be further described below with reference to specific embodiments.

[0030] Combination Figures 1 to 5As shown, this embodiment is an artificial wetland system with sewage purification function, including a grit chamber 100, at least one bioreactor 200, and an artificial wetland structure 300. Polluted river water 110 is pumped into the grit chamber 100, where the grit chamber 100 can settle particulate matter in the polluted river water 110. At least one bioreactor 200 is provided at the output end of the grit chamber 100. The polluted river water 110 after sedimentation treatment in the grit chamber 100 flows into the bioreactor 200. The bioreactor 200 can perform a primary purification treatment on the polluted river water 110 after sedimentation in the grit chamber 100, so as to perform physical filtration and biodegradation on the polluted river water 110. The output end of the bioreactor 200 is equipped with an artificial wetland structure 300. The polluted river water 110 after primary purification by the bioreactor 200 flows into the artificial wetland structure 300. The artificial wetland structure 300 can perform secondary purification on the polluted river water 110 after primary purification by the bioreactor 200, so as to filter the residual pollutants in the polluted river water 110 through media filtration and plant absorption.

[0031] In some implementation schemes, such as Figure 2 As shown, the bioreactor 200 includes a reactor body and a multi-layer filter media layer 210. The multi-layer filter media layer 210 is stacked inside the reactor body. A first inlet 230 is provided at the top of the side wall on one side of the reactor body, and an outlet 240 is provided at the bottom of the side wall on the other side of the reactor body, so that the polluted river water 110 flows from the top of the multi-layer filter media layer 210 to its bottom. The multi-layer filter media layer 210 can remove some of the pollutants in the polluted river water 110.

[0032] Furthermore, the multi-layer filter media layer 210 includes, from bottom to top, a first granular layer 211, a bio-stone layer 212, a second granular layer 213, and a porous mineral material layer 214. The first granular layer 211 includes zeolite and biochar, which can adsorb ammonia nitrogen and heavy metals, and cultivate aerobic bacteria to decompose pollutants. The bio-stone layer 212 includes ceramic particles, which can attach microorganisms to purify polluted river water 110 and enhance biological treatment capacity. The second granular layer 213 includes gravel, which further filters fine suspended solids. The porous mineral material layer 214 includes a mixture of zeolite and olivine in a 1:1 volume ratio, which can attach microorganisms to purify polluted river water 110.

[0033] Furthermore, the particle size of biochar is 20mm~35mm, the particle size of ceramic particles is 15mm~50mm, the particle size of gravel is 2mm~5mm, and the particle size of the mixture of zeolite and olivine is 10mm~30mm.

[0034] By arranging the overall particle size roughly from large to small, it is beneficial to classify and retain pollutants and prevent blockage.

[0035] Furthermore, the thickness ratio of the first particle layer 211, the bio-stone layer 212, the second particle layer 213, and the porous mineral material layer 214 is 1:3:4:2.

[0036] The design of multiple thickness ratios optimizes the balance between hydraulic retention time and purification efficiency.

[0037] Furthermore, a water collection tank 220 is provided between adjacent bioreactors 200. The outlet 240 at the bottom of the bioreactor 200 is connected to the water collection tank 220. The top of the side wall of the water collection tank 220 is provided with a first inlet 230 that can connect to the next stage bioreactor 200. The top of the side wall of the final stage water collection tank 220 is provided with a water guide pipe 250 that can connect to the artificial wetland structure 300, so that the water treated by the previous stage bioreactor 200 is collected in the water collection tank 220 and then overflows into the next stage bioreactor 200.

[0038] The bioreactor 200 and the water collection tank 220 work together, with the water collection tank 220 acting as a transition and buffer to ensure a smooth water flow. The overall modular design allows for flexible configuration of the treatment scale according to the water volume, as well as multi-stage series deep treatment to improve the overall effluent quality.

[0039] Furthermore, in this embodiment, two bioreactors 200 are connected in series. The output end of the bioreactor 200 is connected to a water collection tank 220, so that the polluted river water 110 discharged from the sedimentation tank 100 enters the first bioreactor 200 through the first inlet 230. Under the action of gravity, the polluted river water 110 is purified by multiple layers of media in the first bioreactor 200. Through layer-by-layer physical interception combined with biodegradation mechanism, the pollutant removal efficiency is improved. The purified water is discharged to the first water collection tank 220 through the bottom outlet 240. The water level in the first water collection tank 220 rises until the water in the first water collection tank 220 flows into the second bioreactor 200 through the first inlet 230. The polluted river water 110 is then purified by multiple layers of media in the second bioreactor 200. The purified water is discharged to the second water collection tank 220 through the bottom outlet 240. The water level in the second water collection tank 220 rises until the water in the second water collection tank 220 flows into the artificial wetland structure 300 through the water guide pipe 250.

[0040] In some embodiments, an air injection device 215 is also provided at the bottom of the bioreactor 200. The air injection device 215 is connected to an external air source, and its output end is located below the multilayer filter media layer 210, enabling air to be injected into the multilayer filter media layer 210. In this embodiment, the air injection hole size of the air injection device 215 is 10μm. When the multilayer filter media layer 210 becomes clogged due to the biological reaction, air can be injected into the bioreactor 200 through the air injection device 215 to clean the multilayer filter media layer 210.

[0041] The air injection device 215 enables regular ventilation, which effectively prevents blockage of the packing layer, extends its service life, and provides oxygen to promote the activity of aerobic microorganisms and enhance the degradation efficiency of pollutants.

[0042] In some implementations, the bottom of the bioreactor 200 is also equipped with a sludge collection device, which can collect the sludge generated when polluted river water 110 flows through the multi-layer filter media layer 210. The bottom of the sludge collection device is connected to a sludge discharge pipe 216, which can discharge the collected sludge.

[0043] By promptly removing deposited sludge, the system can prevent siltation from affecting treatment efficiency, reduce the risk of secondary pollution, and facilitate subsequent resource recovery or harmless treatment of the sludge.

[0044] In some implementation schemes, such as Figure 3 As shown, the constructed wetland structure 300 includes a box 320 with an inverted trapezoidal structure and internal packing material 310. The top of the box 320 is provided with a second inlet 330 that can connect to the output end of the bioreactor 200, so that the water after the bioreactor 200 has been purified once is introduced into the box 320 through the second inlet 330. The box 320 is provided with layered stacked internal packing material 310. The water flowing through the internal packing material 310 can be filtered step by step. The top of the internal packing material 310 is provided with aquatic plants 360 with excellent purification ability and economic value.

[0045] Furthermore, the internal filler 310 includes, from bottom to top, a pebble layer 311, a gravel layer 312, a zeolite layer 313, a ceramic particle layer 314, and a planting layer 315. A porous pipe 350 is embedded in the pebble layer 311. Geotextile 316 is laid between each medium layer to separate different fillers and prevent mixing. The thickness ratio of the pebble layer 311, gravel layer 312, zeolite layer 313, ceramic particle layer 314, and planting layer 315 is 2:2:1:2:3. The aquatic plants 360 include reeds, calamus, etc.

[0046] The inverted trapezoidal structure of the tank 320 facilitates uniform water distribution and drainage, preventing short-circuiting. The layered packing design within the tank 320 enhances filtration and adsorption capacity, improving pollutant removal rates. Specifically, a pebble layer 311 provides structural support and assists drainage; a gravel layer 312 performs preliminary filtration; a zeolite layer 313 adsorbs ammonia nitrogen; a ceramic particle layer 314 enhances microbial adhesion; and a planting layer 315 provides a suitable environment for plant growth, facilitating root absorption and microbial degradation. Aquatic plants 360 (such as reeds and calamus) absorb nitrogen and phosphorus, beautify the environment, and enhance ecological benefits. Simultaneously, geotextile 316 isolates the layers, preventing mix-ups and ensuring structural stability and treatment performance.

[0047] Furthermore, the porous pipe 350 is connected to a water storage tank 351 via a first pipe, and the porous pipe 350 is connected to a river via a second pipe, so that the water inside the tank 320 can be stored in the outlet tank via the first pipe or discharged into the river via the second pipe after being filtered by the internal packing material 310.

[0048] The separate arrangement of the first and second pipelines enables the dual functions of water reuse and compliant discharge. The effluent can be selected to enter the water storage tank 351 for irrigation or other purposes, or discharged into natural water bodies after meeting the standards, which helps to improve the system's flexibility and applicability.

[0049] like Figure 4 and Figure 5 As shown in the embodiment, the implementation principle of an artificial wetland system with wastewater purification function is as follows: In stage S1, polluted river water 110 enters the sedimentation tank 100. Utilizing the principle of gravity sedimentation, large suspended particles (such as silt, organic debris, etc.) in the polluted river water 110 naturally settle in the sedimentation tank 100. This process removes large-particle suspended pollutants, reduces the load on subsequent treatment units, and features a simple structure, convenient maintenance, and low operating costs.

[0050] In stage S2-1, the effluent from the grit chamber 100 enters the first-stage bioreactor 200. The water flows downwards through a multi-layered filter layer, where each layer performs adsorption, retention, and microbial degradation functions. Simultaneously, an air injection device 215 and a sludge collection device are located at the bottom of the system. Specifically, the filter layer removes fine particles through physical filtration, while biochar, zeolite, and other materials cultivate aerobic bacteria to degrade organic matter. The ceramic layer provides a carrier for microorganisms, enhancing biological treatment capacity. Air injection prevents clogging and promotes biological activity, and automatic sludge collection reduces the risk of secondary pollution.

[0051] In stage S2-2, the effluent from the first-stage bioreactor 200 flows into the second-stage bioreactor 200 via the collection tank 220. The effluent from the previous stage overflows into the next-stage bioreactor 200 after entering the collection tank 220. The second stage continues deep physical filtration and biodegradation treatment, improving the removal rate of pollutants such as nitrogen, phosphorus, and COD. The overall modular design facilitates expansion and maintenance, not only buffering water volume fluctuations but also enhancing the system's resistance to shock loads.

[0052] In stage S3, the effluent from the bioreactor 200 is introduced into the constructed wetland structure 300. The pre-purified water enters from multiple inlets at the top of the wetland, flowing downwards through layers of pebbles 311, gravel 312, zeolite 313, ceramic particles 314, and a planting layer 315. Aquatic plants such as reeds and cattails 360 are planted at the top of the wetland, forming a rich microbial community around their roots. Porous pipes 350 are laid at the bottom to collect the purified water. The plant roots absorb nutrients such as nitrogen and phosphorus, and rhizosphere microorganisms further decompose residual organic matter. Multiple filler materials synergistically adsorb heavy metals and trace pollutants, and geotextile 316 isolates different filler layers to prevent mixing and maintain treatment efficiency. The constructed wetland structure 300 beautifies the environment, serving both landscape and ecological restoration functions.

[0053] The purified water from the constructed wetland is collected through a porous pipe 350 at the bottom. The water can be selectively introduced into a storage tank 351 for irrigation or other purposes, or discharged into natural water bodies after meeting standards. This not only enables the reuse of water resources (such as agricultural irrigation and greening water), but also ensures that the effluent quality is consistently up to standard, meeting environmental discharge requirements, further enhancing the system's flexibility and making it suitable for different application scenarios.

[0054] The above are all preferred embodiments of this utility model, and are not intended to limit the scope of protection of this utility model. Therefore, all equivalent changes made to the structure, shape and principle of this utility model should be covered within the scope of protection of this utility model.

Claims

1. An artificial wetland system with wastewater purification function, characterized in that, include: A sedimentation tank (100) is introduced into polluted river water (110) at its input end, which can settle particulate matter in the polluted river water (110); At least one bioreactor (200) is located at the output end of the sedimentation tank (100) and is capable of performing a primary purification treatment on the polluted river water (110) after sedimentation in the sedimentation tank (100) to perform physical filtration and biodegradation on the polluted river water (110). An artificial wetland structure (300) is located at the output end of a bioreactor (200) and can perform secondary purification treatment on polluted river water (110) after primary purification treatment by the bioreactor (200) to filter and absorb some of the pollutants remaining in the polluted river water (110) through media filtration.

2. The constructed wetland system with wastewater purification function according to claim 1, characterized in that: The bioreactor (200) includes a reactor body and a multi-layer filter media layer (210). The multi-layer filter media layer (210) is stacked inside the reactor body. A first inlet (230) is provided at the top of the side wall on one side of the reactor body, and an outlet (240) is provided at the bottom of the side wall on the other side of the reactor body, so that polluted water flows from the top of the multi-layer filter media layer (210) to its bottom. The multi-layer filter media layer (210) can remove some pollutants from the polluted water.

3. The constructed wetland system with wastewater purification function according to claim 2, characterized in that: The multi-layer filter media layer (210) includes, from bottom to top, a first particle layer (211), a bio-stone layer (212), a second particle layer (213), and a porous mineral material layer (214). The first particle layer (211) can cultivate aerobic bacteria to decompose pollutants. The bio-stone layer (212) includes ceramic particles that can attach microorganisms to purify polluted river water (110). The second particle layer (213) includes gravel. The porous mineral material layer (214) can attach microorganisms to purify polluted river water (110).

4. The constructed wetland system with wastewater purification function according to claim 3, characterized in that: The ceramic particles have a particle size of 15mm to 50mm, and the gravel has a particle size of 2mm to 5mm. The thickness ratio of the first particle layer (211), the biorock layer (212), the second particle layer (213), and the porous mineral material layer (214) is 1:3:4:

2.

5. The constructed wetland system with wastewater purification function according to claim 2, characterized in that: A water collection tank (220) is provided between adjacent bioreactors (200). The outlet (240) at the bottom of the bioreactor (200) is connected to the water collection tank (220). The top of the side wall of the water collection tank (220) is provided with a first inlet (230) that can be connected to the next stage bioreactor (200). The top of the side wall of the final stage water collection tank (220) is provided with a water guide pipe (250) that can be connected to the artificial wetland structure (300), so that the water treated by the previous stage bioreactor (200) gathers in the water collection tank (220) and overflows into the next stage bioreactor (200).

6. The constructed wetland system with wastewater purification function according to claim 2, characterized in that: The bottom of the bioreactor (200) is also provided with an air injection device (215). The air injection device (215) is connected to an external air source. The output end of the air injection device (215) is located below the multi-layer filter media layer (210) and can inject air into the multi-layer filter media layer (210).

7. The constructed wetland system with wastewater purification function according to claim 2, characterized in that: The bottom of the bioreactor (200) is also equipped with a sludge collection device, which can collect the sludge generated by the polluted river water (110) flowing through the multi-layer filter media layer (210). The bottom of the sludge collection device is connected to a sludge discharge pipe (216), which can discharge the collected sludge.

8. The constructed wetland system with wastewater purification function according to claim 1, characterized in that: The constructed wetland structure (300) includes a box (320) with an inverted trapezoidal structure and internal packing (310). The top of the box (320) is provided with a second inlet (330) that can connect to the output end of the bioreactor (200), so that the water after the bioreactor (200) is purified once is introduced into the box (320) through the second inlet (330). The box (320) is provided with layered stacked internal packing (310). The water flowing through the internal packing (310) can be filtered step by step. Aquatic plants (360) are provided on the top of the internal packing (310).

9. The constructed wetland system with wastewater purification function according to claim 8, characterized in that: The internal filler (310) includes, from bottom to top, a pebble layer (311), a gravel layer (312), a zeolite layer (313), a ceramic particle layer (314), and a planting layer (315). A porous pipe (350) is embedded in the pebble layer (311), and geotextile (316) is laid between each medium layer. The thickness ratio of the pebble layer (311), gravel layer (312), zeolite layer (313), ceramic particle layer (314), and planting layer (315) is 2:2:1:2:

3. The aquatic plants (360) include reeds and calamus.

10. The constructed wetland system with wastewater purification function according to claim 9, characterized in that: The porous pipe (350) is connected to a water storage tank (351) via a first pipe, and the porous pipe (350) is connected to a river via a second pipe, so that the water inside the tank (320) can be stored in the outlet tank via the first pipe or discharged into the river via the second pipe after being filtered by the internal packing material (310).

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