Modularized turn-back type wetland device and sewage treatment system

Abstract

The invention provides a modular turn-back type wetland device and a sewage treatment system. The modular turn-back type wetland device comprises a water distribution unit, a wetland reaction unit and a drainage unit which are sequentially arranged in the water flow direction, the water distribution unit comprises a first-stage water distribution module and a second-stage water distribution module which are connected in sequence; the wetland reaction unit comprises a plurality of reaction bed main bodies which are arranged side by side, each reaction bed main body comprises a water inlet area, a reaction area and a water collecting area which are communicated in sequence, the water inlet area is connected with the secondary water distribution module, and the water collecting area is connected with the drainage unit; a first modular filler, a second modular filler and a third modular filler are respectively arranged in the water inlet area, the reaction area and the water collecting area, and the first modular filler, the second modular filler and the third modular filler are different from one another. The device has the advantages of high hydraulic load, good treatment effect, difficulty in blockage, convenience in operation, maintenance and cleaning and the like.

Description

Technical Field

[0001] The invention belongs to the technical field of artificial wetlands, and relates to a modular return wetland device and a sewage treatment system. Background Art

[0002] At present, with the improvement of residents' living standards, residents' requirements for the quality of water ecological environment in river and lake basins are also increasing. At present, there is a widespread problem of micro-pollution in the water systems of domestic river and lake basins, and the problem of exceeding the standard in sections is prominent. Water pollution not only has a negative impact on the water ecological structure, but also increases the risk of water safety in the basin. In recent years, in order to promote the construction of ecological civilization, the water environment management and water ecological restoration of micro-polluted water bodies have become important tasks for government units at all levels.

[0003] Micro-polluted water bodies are characterized by complex water properties, low pollutant concentrations, and large fluctuations in water volume. Their pollution sources mainly include sewage treatment plant effluent, surface runoff, agricultural pollution, etc. Among them, the current Level A emission standard of the "Pollutant Discharge Standard for Urban Sewage Treatment Plants" is inferior to the "Surface Water Environmental Quality Standard" and belongs to Class V water quality. Even if the sewage treatment plant meets the emission standards, it will still form a pollution load impact on the discharged water body.

[0004] In response to the problem of micro-pollution in water bodies, artificial wetland technology has the advantages of investment savings, simple operation and maintenance, and natural ecology, and has broad application prospects, especially subsurface artificial wetland technology, which is widely used in water bypass treatment and sewage treatment plant tailwater treatment. However, subsurface wetlands have also encountered many engineering challenges in practice. Traditional subsurface wetlands are mainly divided into two types according to their structural types: horizontal flow and vertical flow. Horizontal subsurface wetlands have uneven water distribution and low treatment load; while vertical subsurface wetlands have even water distribution but are prone to clogging. During the long-term operation of wetlands, problems such as clogging, reduced operating efficiency, and difficulty in cleaning have been encountered, which have limited the application and development of subsurface wetlands.

[0005] Therefore, it is necessary to provide a new type of subsurface wetland to solve the problems existing in existing wetlands. Summary of the invention

[0006] In view of the shortcomings of the prior art, the purpose of the present invention is to provide a modular reentry wetland device and sewage treatment system, which solves the problems of uneven water distribution and easy clogging in subsurface flow wetlands, and has the advantages of high hydraulic load, good treatment effect, not easy to clog, and easy operation and maintenance and cleaning.

[0007] In the first aspect, the present invention provides a modular reentrant wetland device, which includes a water distribution unit, a wetland reaction unit and a drainage unit arranged in sequence along the water flow direction; the water distribution unit includes a primary water distribution module and a secondary water distribution module connected in sequence; the wetland reaction unit includes a plurality of reaction bed bodies arranged side by side, the reaction bed body includes a water inlet area, a reaction area and a water collection area connected in sequence, the water inlet area is connected to the secondary water distribution module, and the water collection area is connected to the drainage unit; the water inlet area, the reaction area and the water collection area are respectively provided with a first modular filler, a second modular filler and a third modular filler, and the first modular filler, the second modular filler and the third modular filler are different from each other.

[0008] The present invention realizes uniform water distribution of each wetland reaction bed through a two-level water distribution design, simplifies operation and maintenance, and reduces investment. At the same time, the modular fillers are coupled and assembled into the wetland reaction beds, which solves the problem that the fillers are easy to be blocked and difficult to clean during the operation and maintenance of the subsurface flow wetland. Different filler modules are selected according to different water conditions to improve the mass transfer effect inside the wetland and improve the effluent water quality.

[0009] As a preferred technical solution of the present invention, the first modular filler, the second modular filler and the third modular filler independently include a plurality of rectangular frames, the rectangular frames are wrapped with hollow mesh surfaces, and the rectangular frames are filled with reactive fillers.

[0010] The average particle sizes of the reactive fillers in the first modular filler, the second modular filler, and the third modular filler are different from each other.

[0011] The mesh apertures of the hollow mesh surfaces of the first modular filler, the second modular filler and the third modular filler are different from each other.

[0012] Preferably, the rectangular frame and the reaction bed body, as well as two adjacent rectangular frames, are detachably connected.

[0013] Each side surface of the rectangular frame body in the present invention is provided with a hollow mesh surface to form a porous filler module to avoid clogging of the filler.

[0014] As a preferred technical solution of the present invention, the average particle size of the reactive filler in the first modular filler is recorded as the first particle size, the average particle size of the reactive filler in the second modular filler is recorded as the second particle size, and the average particle size of the reactive filler in the third modular filler is recorded as the third particle size. The first particle size and the third particle size are independently larger than the second particle size; the first particle size and the third particle size are the same or different.

[0015] Preferably, the first particle size and the third particle size are independently 40 to 100 mm, for example, 40 mm, 45 mm, 50 mm, 55 mm, 60 mm, 65 mm, 70 mm, 80 mm, 90 mm or 100 mm, but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0016] Preferably, the second particle size is 10-40 mm, for example, 10 mm, 12 mm, 15 mm, 20 mm, 23 mm, 25 mm, 28 mm, 30 mm, 32 mm, 35 mm, 38 mm or 40 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0017] Preferably, the reactive filler comprises porous ceramsite.

[0018] As a preferred technical solution of the present invention, the mesh aperture of the hollow mesh surface of the first modular filler is recorded as the first aperture, the mesh aperture of the hollow mesh surface of the second modular filler is recorded as the second aperture, and the mesh aperture of the hollow mesh surface of the third modular filler is recorded as the third aperture. The first aperture and the third aperture are independently larger than the second aperture; the first aperture and the third aperture are the same or different.

[0019] Preferably, the first aperture and the third aperture are independently 3 to 6 cm, for example, 3 cm, 3.5 cm, 4 cm, 4.5 cm, 5 cm, 5.5 cm or 6 cm, but are not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0020] Preferably, the second aperture is 1 to 3 cm, for example, 1 cm, 1.2 cm, 1.5 cm, 1.8 cm, 2 cm, 2.3 cm, 2.5 cm, 2.6 cm, 2.8 cm or 3 cm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] As a preferred technical solution of the present invention, a water purification biological layer is arranged on the top of the first modular filler, the second modular filler and the third modular filler.

[0022] Preferably, the plants in the water purification biological layer include any one of reed, cattail, calamus, iris, loosestrife, lily or canna, or a combination of at least two of them.

[0023] The present invention plants emergent plants with strong water purification ability on the filler, which can achieve full contact between pollutants and microorganisms and the roots of the emergent plants, and complete water purification through the purification of microorganisms and absorption by the plant roots.

[0024] As a preferred technical solution of the present invention, the first-level water distribution module includes a water distribution channel, and the second-level water distribution module includes a plurality of water distribution channels arranged side by side, the water distribution channels correspond to the reaction bed body one by one, and the water distribution channels are connected to the reaction bed body; a lower-opening weir gate is provided at the inlet end of the water distribution channel, and the water distribution channel is connected to the water distribution channel through the lower-opening weir gate.

[0025] Preferably, a first inspection hole is provided on the top of the water distribution channel, and a first grille cover is laid on the first inspection hole.

[0026] Preferably, a main water injection pipe is also provided at the inlet end of the water distribution channel.

[0027] Preferably, a shunt pipe is provided at the inlet end of the reaction bed body, and the shunt pipe is connected to the water distribution channel.

[0028] Preferably, a plurality of first communication holes are distributed on the surface of the shunt pipe.

[0029] Preferably, a plurality of first exhaust holes are formed on the top surface of the diverter pipe.

[0030] Preferably, the distance between the bottom surface of the diverter tube and the bottom surface of the inner cavity of the reaction bed body is 20 to 30 cm, for example, it can be 20 cm, 21 cm, 22 cm, 23 cm, 24 cm, 25 cm, 26 cm, 27 cm, 28 cm, 29 cm or 30 cm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0031] The primary water distribution module in the present invention is a connecting channel, which can evenly distribute water to each water distribution channel in the secondary water distribution module. The secondary water distribution module distributes water to multiple units and evenly distributes water to each wetland reaction bed body.

[0032] As a preferred technical solution of the present invention, the drainage unit includes a plurality of water outlet channels, the water outlet channels correspond to the reaction bed body one by one, and the inlet ends of the water outlet channels are connected to the reaction bed body.

[0033] Preferably, a second inspection hole is provided at the top of the water outlet channel, and a second grille cover is laid on the second inspection hole.

[0034] Preferably, a main drainage pipe is provided at the outlet end of the drainage unit, and the main drainage pipe is connected to a plurality of the outlet channels respectively.

[0035] Preferably, a telescopic tube is further provided inside the outlet channel, one end of the telescopic tube is connected to the inlet of the main drainage pipe, and the other end of the telescopic tube is freely telescopic in a direction perpendicular to the water flow.

[0036] Preferably, a collecting pipe is provided at the outlet end of the reaction bed body, and the collecting pipe is connected to the water outlet channel.

[0037] Preferably, a plurality of second connecting holes are distributed on the surface of the collecting pipe.

[0038] Preferably, a plurality of second exhaust holes are formed on the top surface of the manifold.

[0039] Preferably, the distance between the bottom surface of the collecting pipe and the bottom surface of the inner cavity of the reaction bed body is 20 to 30 cm, for example, it can be 20 cm, 21 cm, 22 cm, 23 cm, 24 cm, 25 cm, 26 cm, 27 cm, 28 cm, 29 cm or 30 cm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0040] As a preferred technical solution of the present invention, a plurality of upper guide partition walls and a plurality of lower guide partition walls extending perpendicular to the water flow direction are arranged in the reaction bed body, and the upper guide partition walls and the lower guide partition walls are alternately arranged along the water flow direction. A first guide port is provided at the top of the upper guide partition wall, and a second guide port is provided at the bottom of the lower guide partition wall, so that the water flow in the reaction bed body is in an upward and downward bendable flow; a first modular filler, a second modular filler or a third modular filler is provided between adjacent upper guide partition walls and lower guide partition walls.

[0041] Preferably, the water inlet area is formed between the inlet end of the reaction bed body and the upper guide partition wall or the lower guide partition wall located at the front end; the water collection area is formed between the outlet end of the reaction bed body and the upper guide partition wall or the lower guide partition wall located at the rear end, and the remaining upper guide partition walls and the lower guide partition walls are alternately arranged in the reaction zone.

[0042] In the present invention, the water flow entering the reaction bed body from the water distribution unit flows through the reaction bed body in an up-and-down return route under the guidance of the upper and lower flow guide partition walls, and then enters the drainage unit.

[0043] Preferably, the volume of the reaction zone is 4 to 8 times the volume of the water inlet zone, for example, 4 times, 4.5 times, 5 times, 6 times, 7 times or 8 times, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0044] As a preferred technical solution of the present invention, an anti-seepage structure is also provided at the bottom of the reaction bed body, and a cloth-membrane composite layer is provided inside the anti-seepage structure. The cloth-membrane composite layer includes a first geotextile, a dense membrane and a second geotextile stacked in sequence.

[0045] Preferably, the unit density of the first geotextile and the second geotextile is independently 300-400 g / m 2 , for example, it can be 300g / m 2 , 310g / m 2 , 320g / m 2 , 330g / m 2 , 340g / m 2 , 350g / m 2 , 360g / m 2 , 370g / m 2 , 380g / m 2 , 390g / m 2 or 400g / m 2 , but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0046] Preferably, the thickness of the dense film is 0.5-1 mm, for example, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0047] Preferably, the dense film is a HDPE (high-density polyethylene) film.

[0048] In a second aspect, the present invention provides a sewage treatment system, which includes the modular return wetland device described in the first aspect.

[0049] The present invention purifies sewage based on artificial wetland technology and has the advantages of large hydraulic load, good treatment effect, convenient maintenance and low operation and maintenance cost.

[0050] The sewage treatment system of the present invention has a wide range of applications and can be applied to the purification of various sewage and wastewater, including but not limited to domestic sewage, slightly polluted sewage, tail water from sewage treatment plants, and the like.

[0051] The system refers to an equipment system, a device system or a production device.

[0052] Compared with the prior art, the present invention has the following beneficial effects:

[0053] (1) The modular return wetland device and sewage treatment system provided by the present invention has the advantages of uniform water distribution and simple operation and maintenance through a two-stage water distribution design. There is no need to arrange large-scale water collection and distribution pipes on the top and bottom of the pool body, thus avoiding the problem of easy pipe blockage encountered in traditional vertical flow subsurface wetlands. It has a more uniform internal flow field, a high hydraulic load and is not easy to be blocked.

[0054] (2) The present invention uses lightweight, porous fillers to modularly assemble the wetland reaction bed. During the operation and maintenance of the wetland, the fillers can be easily disassembled and cleaned after being blocked, thus solving the problem that the fillers in the subsurface flow wetland are easy to be blocked and difficult to clean.

[0055] (3) The present invention selects different modular fillers according to different conditions of water flow in the reaction bed to ensure the water purification effect and greatly improve the effluent quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0056] Figure 1 This is a schematic structural diagram of the modular return wetland device provided in Example 1 of the present invention.

[0057] Figure 2 A top view of the modular return wetland device provided in Example 1 of the present invention.

[0058] Figure 3 This is a schematic structural diagram of the first modular packing provided in Example 1 of the present invention.

[0059] Among them, 11-water distribution channel; 12-main water injection pipe; 13-water distribution channel; 14-lower opening weir gate; 15-first inspection hole; 16-first grille cover; 21-reaction bed body; 211-wetland outer wall; 212-middle partition wall; 213-upper diversion partition wall; 214-lower diversion partition wall; 221-diversion pipe; 222-collecting pipe; 23-first modular filler; 231-rectangular frame; 232-hollow mesh surface; 233-porous expanded clay; 24-anti-seepage structure; 242-membrane composite layer; 25-water purification biological layer; 31-outlet channel; 32-second inspection hole; 33-second grille cover; 34-telescopic pipe; 35-main drainage pipe. DETAILED DESCRIPTION

[0060] It should be understood that, in the description of the present invention, the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first", "second", etc. are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0061] It should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "disposed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0062] Those skilled in the art should understand that the present invention necessarily includes necessary pipelines, conventional valves and general pump equipment for realizing a complete process, but the above content does not belong to the main inventive point of the present invention. Those skilled in the art can add layouts on their own based on the process flow and equipment structure selection, and the present invention does not make special requirements and specific limitations on this.

[0063] The technical solution of the present invention is further described below with reference to the accompanying drawings and through specific implementation methods.

[0064] In a specific embodiment, the present invention provides a modular return wetland device, including a water distribution unit, a wetland reaction unit and a drainage unit arranged in sequence along the water flow direction. The water distribution unit includes a primary water distribution module and a secondary water distribution module connected in sequence. The wetland reaction unit includes a plurality of reaction bed bodies arranged side by side, and the reaction bed body includes a water inlet area, a reaction area and a water collection area connected in sequence, the water inlet area is connected to the secondary water distribution module, and the water collection area is connected to the drainage unit. The present invention adopts a two-stage water distribution design, the water flow in the primary water distribution module enters the secondary water distribution module, and then flows evenly into the reaction bed body, and then flows through the water inlet area, the reaction area and the water collection area in sequence and enters the drainage unit. The first modular filler, the second modular filler and the third modular filler are respectively arranged in the water inlet area, the reaction area and the water collection area, and the first modular filler, the second modular filler and the third modular filler are different from each other, so that the water flow is fully in contact with different fillers when passing through the water inlet area, the reaction area and the water collection area, so as to achieve a purification effect.

[0065] In some embodiments, the primary water distribution module includes a water distribution channel, which adopts a connecting channel. The inlet end of the water distribution channel is also provided with a main water injection pipe for injecting water into the water distribution channel. The secondary water distribution module includes a plurality of water distribution channels arranged side by side, and the water distribution channels correspond to the reaction bed body one by one. The water distribution channels are connected to the reaction bed body to distribute water to a single reaction bed body. The water distribution channel is connected to a plurality of water distribution channels respectively. Specifically, a water distribution hole is provided between the water distribution channel and the water distribution channel for water distribution, and a downward opening weir gate is provided at the inlet end of the water distribution channel, that is, the front end of the water distribution hole, to realize the control of the water inlet switch, adjust the flow of the secondary water distribution module, and then control the water inlet flow of each reaction bed body, so as to facilitate the subsequent operation, adjustment and maintenance of the wetland. The water distribution channel and the water distribution channel are both built with a wall structure of a certain thickness to avoid water leakage. In addition, a first inspection hole is provided at the top of the water distribution channel, and a first grille cover is laid on the first inspection hole, and the first grille cover can be freely movable, disassembled or moved. After the lower opening weir gate is closed and the water distribution channel of the secondary water distribution module is emptied, the operation and maintenance personnel can inspect and maintain the pipeline connecting the water distribution channel and the reaction bed body.

[0066] The inlet end of the reaction bed body is provided with a shunt pipe, and the shunt pipe is connected to the water distribution channel. Specifically, the shunt pipe is arranged in the water inlet area of ​​the reaction bed body. A plurality of first connecting holes are distributed on the surface of the shunt pipe, which are specifically arranged at 45° obliquely below the tube body. A plurality of first exhaust holes are provided on the top surface of the shunt pipe. The shunt pipe is arranged in the reaction bed body along the width direction of the reaction bed body to evenly distribute water. The distance between the bottom surface of the shunt pipe and the bottom surface of the inner cavity of the reaction bed body is 20 to 30 cm. The shunt pipe is made of PVC (polyvinyl chloride) material well known to those skilled in the art, which has good mechanical properties, is wear-resistant, acid-resistant and alkali-resistant, and has good stability.

[0067] In some embodiments, the drainage unit includes a plurality of outlet channels, each of which corresponds to the reaction bed body, and the inlet end of each of the outlet channels is connected to the reaction bed body. A main drain pipe is provided at the outlet end of the drainage unit, and each of the main drain pipes is connected to a plurality of the outlet channels. Furthermore, a telescopic pipe is provided inside the outlet channel, one end of which is connected to the inlet of the main drain pipe, and the other end is freely retracted in a direction perpendicular to the water flow, so that the height of the telescopic pipe can be adjusted, thereby adjusting the water level of the reaction bed body, and the telescopic pipe is connected to the main drain pipe to discharge the purified water into the surface water body. In addition, the outlet channel is constructed by a wall structure of a certain thickness to avoid water leakage. A second inspection hole is provided at the top of the outlet channel for inspecting and maintaining the pipe connecting the reaction bed body and the outlet channel, and a second grille cover is laid on the second inspection hole, and the first grille cover can be freely movable, disassembled or moved.

[0068] The outlet end of the reaction bed body is provided with a collecting pipe, and the collecting pipe is connected to the outlet channel. Specifically, the collecting pipe is arranged in the water collection area of ​​the reaction bed body. A plurality of second connecting holes are distributed on the surface of the collecting pipe, which are specifically arranged at 45 degrees obliquely below the tube body. A plurality of second exhaust holes are provided on the top surface of the collecting pipe. The distance between the bottom surface of the collecting pipe and the bottom surface of the inner cavity of the reaction bed body is 20 to 30 cm. The collecting pipe is made of PVC material well known to those skilled in the art, which has good mechanical properties, is wear-resistant, acid-resistant and alkali-resistant, and has good stability.

[0069] It should be noted that the water distribution unit, reaction unit and drainage unit of the present invention are also provided with necessary connecting pipes and switch control valves. The present invention does not make special limitations on this. Technical personnel in this field need to reasonably adjust, add or delete according to actual production needs. It should be clear that new technical solutions generated by deleting some unnecessary connecting pipes and switch control valves, or replacing single-function switch control valves with multi-function integrated control valves, or using an automatic control system in which an external device is electrically connected to the switch control valve to control the opening of the corresponding valve, etc., which are common and well-known conventional technical means for technical personnel in this field, also fall within the scope of disclosure and protection of the present invention.

[0070] In some embodiments, the first modular filler, the second modular filler and the third modular filler independently include a plurality of rectangular frames, the rectangular frames are wrapped with hollow meshes, and the rectangular frames are filled with reactive fillers. The rectangular frame serves as a skeleton, and its six surfaces are provided with hollow meshes to facilitate water circulation. The rectangular frame is made of steel bars with high structural strength, and the hollow meshes are made of metal wire or alloy. The metal wires include but are not limited to iron wire, lead wire, steel wire and aluminum wire, preferably lead wire. A plurality of rectangular frames are stacked in multiple layers to form a modular filler, and the rectangular frame is detachably connected to the reaction bed body and the two adjacent rectangular frames. The present invention does not specifically limit the detachable connection method, and can be a snap connection, bolt connection, hinge connection, rivet connection, pin connection, interference connection and other connection methods commonly used in the art, and those skilled in the art can adjust according to actual conditions. The reactive filler includes lightweight porous ceramsite. The porous ceramsite can be made from natural ores or light raw materials known to those skilled in the art through a crushing process, including but not limited to pumice, volcanic slag, coal slag, natural coal gangue, calcined coal gangue, and the like.

[0071] In some embodiments, the average particle sizes of the reactive fillers in the first modular filler, the second modular filler, and the third modular filler are different from each other. The mesh apertures of the hollow mesh surfaces of the first modular filler, the second modular filler, and the third modular filler are different from each other.

[0072] Further, the average particle size of the reaction filler in the first modular filler is recorded as the first particle size, the average particle size of the reaction filler in the second modular filler is recorded as the second particle size, and the average particle size of the reaction filler in the third modular filler is recorded as the third particle size. The first particle size and the third particle size are independently larger than the second particle size; the first particle size and the third particle size are the same or different. Preferably, the first particle size is 40 to 100 mm, the second particle size is 10 to 40 mm, and the third particle size is 40 to 100 mm.

[0073] Further, the mesh aperture of the hollow mesh surface of the first modular filler is recorded as the first aperture, the mesh aperture of the hollow mesh surface of the second modular filler is recorded as the second aperture, and the mesh aperture of the hollow mesh surface of the third modular filler is recorded as the third aperture. The first aperture and the third aperture are independently larger than the second aperture; the first aperture and the third aperture are the same or different. Preferably, the first aperture is 3 to 6 cm, the second aperture is 1 to 3 cm, and the third aperture is 3 to 6 cm.

[0074] In some embodiments, a water purification biological layer is arranged on the top of the first modular filler, the second modular filler and the third modular filler, so that pollutants and microorganisms can be fully contacted with the roots of emergent plants, and water quality is purified through the purification of microorganisms and absorption by plant roots. Preferably, the plants in the water purification biological layer include any one of reed, cattail, calamus, iris, loosestrife, lily or canna, or a combination of at least two of them.

[0075] In some embodiments, the reactor bed body is provided with a plurality of upper flow guide partitions and a plurality of lower flow guide partitions extending perpendicular to the water flow direction, and the upper flow guide partitions and the lower flow guide partitions are alternately arranged along the water flow direction. A first flow guide port is provided at the top of the upper flow guide partition, and a second flow guide port is provided at the bottom of the lower flow guide partition, so that the water flow entering the reactor bed body flows through the modular fillers in the water inlet area, the reaction area and the water collection area in an up-and-down return flow path in sequence to achieve the purpose of purification. Specifically, the water inlet area is formed between the inlet end of the reactor bed body and the upper flow guide partition or the lower flow guide partition located at the front end, and the first modular filler is arranged inside the water collection area. The water collection area is formed between the outlet end of the reactor bed body and the upper flow guide partition or the lower flow guide partition located at the rear end, and the third modular filler is arranged inside the water collection area; the remaining upper flow guide partitions and the lower flow guide partitions are alternately arranged in the reaction area, and the second modular filler is arranged between the upper flow guide partition and the lower flow guide partition. Preferably, the volume of the reaction zone is 4 to 8 times the volume of the water inlet zone. Preferably, the guide walls at the front end and the rear end are both upper guide walls.

[0076] In some embodiments, a wetland outer wall is provided outside the reaction bed body, and an intermediate partition wall is provided between two adjacent reaction bed bodies. An anti-seepage structure is also provided at the bottom of the reaction bed body to prevent pollution from seeping in and prevent groundwater from entering the wetland reaction bed. A cloth-membrane composite layer is provided inside the anti-seepage structure, and the cloth-membrane composite layer includes a first geotextile, a dense membrane and a second geotextile stacked in sequence. Specifically, the unit density of the first geotextile and the second geotextile is independently 300 to 400 g / m 2 The thickness of the dense film is 0.5 to 1 mm. Preferably, the dense film is a HDPE film. The anti-seepage structure may also include other necessary soil layers or films known to those skilled in the art, which are not specifically limited in the present invention and may be reasonably adjusted or added by those skilled in the art according to actual production needs.

[0077] In another specific embodiment, the present invention provides a sewage treatment system, which includes a modular reentry wetland device described in a specific embodiment, which purifies sewage based on artificial wetland technology and has the advantages of large hydraulic load, good treatment effect, convenient maintenance and low operation and maintenance cost.

[0078] Example 1

[0079] This embodiment provides a modular return wetland device, including a water distribution unit, a wetland reaction unit and a drainage unit arranged in sequence along the water flow direction. The water distribution unit includes a primary water distribution module and a secondary water distribution module connected in sequence. Figure 1 and Figure 2 As shown, the primary water distribution module includes a water distribution channel 11, and the secondary water distribution module includes a plurality of water distribution channels 13 arranged side by side. A main water injection pipe 12 is also provided at the inlet end of the water distribution channel 11. A lower opening weir gate 14 is provided at the inlet end of each water distribution channel 13, and the water distribution channel 13 is independently connected to the outlet end of the water distribution channel 11 through the lower opening weir gate 14. A first inspection hole 15 is provided at the top of the water distribution channel 13, and a first grille cover plate 16 is laid on the first inspection hole 15.

[0080] The wetland reaction unit includes a plurality of reaction bed bodies 21 arranged side by side, a wetland outer wall 211 is arranged outside the reaction bed body 21, and an intermediate partition wall 212 is arranged between two adjacent reaction bed bodies 21. An anti-seepage structure 24 is arranged at the bottom of the reaction bed body 21, and a cloth-membrane composite layer 242 is arranged inside the anti-seepage structure 24. The cloth-membrane composite layer 242 includes a first geotextile, a dense membrane and a second geotextile stacked in sequence. The unit density of the first geotextile and the second geotextile is independently 300-400g / m 2, the dense membrane adopts a HDPE membrane with a thickness of 0.8mm. The reaction bed body 21 includes a water inlet area, a reaction area and a water collection area which are connected in sequence. The reaction bed body 21 corresponds to the water distribution channel 13 one by one. A diverter pipe 221 is arranged in the water inlet area of ​​the reaction bed body 21, and the diverter pipe 221 is connected to the corresponding water distribution channel 13. A plurality of first connecting holes with a diameter of 15mm are distributed at 45° on both sides of the diverter pipe 221, and a plurality of first exhaust holes with a diameter of 15mm are opened on the top surface of the diverter pipe 221. The distance between the bottom surface of the diverter pipe 221 and the bottom surface of the inner cavity of the reaction bed body 21 is 30cm. A plurality of upper flow guide partitions 213 and a plurality of lower flow guide partitions 214 extending perpendicular to the water flow direction are arranged in the reaction bed body 21, and the upper flow guide partitions 213 and the lower flow guide partitions 214 are arranged alternately and spaced along the water flow direction, a first flow guide port is provided at the top of the upper flow guide partition 213, and a second flow guide port is provided at the bottom of the lower flow guide partition 214. A water inlet area is formed between the inlet end of the reaction bed body 21 and the upper flow guide partition 213 at the front end, and a first modular filler 23 is arranged inside the water inlet area; a plurality of upper flow guide partitions 213 and lower flow guide partitions 214 are arranged alternately in the reaction area, and a second modular filler is arranged between the upper flow guide partitions 213 and the lower flow guide partitions 214, so that the water flow flows into the water collection area through the upper and lower turns; a water collection area is formed between the outlet end of the reaction bed body and the upper flow guide partition 213 at the rear end, and a third modular filler is arranged inside the water collection area. The volume of the reaction zone is 4 times the volume of the water inlet zone. The first modular packing 23, the second modular packing and the third modular packing independently include a plurality of rectangular frames 231 with a size of 1.0m×1.0m×1.0m, such as Figure 3 As shown, the rectangular frame 231 is made of steel bars with a diameter of 12 mm, and the rectangular frame 231 is detachably connected to the reaction bed body 21 and the two adjacent rectangular frames 231. The rectangular frame 231 is wrapped with a hollow mesh 232 made of lead wire, and the rectangular frame 231 is filled with porous ceramsite 233. The mesh aperture of the hollow mesh 232 of the first modular filler 23 in the water inlet area is 3 cm, and the particle size of the porous ceramsite 233 is 40-80 mm; the mesh aperture of the hollow mesh 232 of the second modular filler in the reaction area is 1.5 cm, and the particle size of the porous ceramsite 233 is 20-40 mm; the mesh aperture of the hollow mesh 232 of the third modular filler in the water collection area is 3 cm, and the particle size of the porous ceramsite 233 is 40-80 mm. At the same time, a water purification biological layer 25 is arranged on the top of the first modular filler 23, the second modular filler and the third modular filler, and emergent plants with strong water purification ability such as reed, calamus, water plantain are selected.

[0081] like Figure 1As shown, the drainage unit includes a plurality of outlet channels 31, and the outlet channels 31 correspond to the reaction bed body 21 one by one. A second inspection hole 32 is provided on the top of the outlet channel 31, and a second grille cover 33 is laid on the second inspection hole 32. A main drainage pipe 35 is provided at the outlet end of the drainage unit, and the main drainage pipe 35 is connected to the plurality of outlet channels 31 respectively. A telescopic pipe 34 is also provided inside the outlet channel 31, which is made of PVC and has a pipe diameter of De110. One end of the telescopic pipe 34 is connected to the inlet of the main drainage pipe 35, and the other end is freely retractable in a direction perpendicular to the water flow. A collecting pipe 222 is provided in the water collection area of ​​the reaction bed body 21, and the collecting pipe 222 is connected to the corresponding outlet channel 31. A plurality of second connecting holes with a diameter of 15 mm are distributed at 45° obliquely downward on both sides of the collecting pipe 222, and a plurality of second exhaust holes with a diameter of 15 mm are opened on the top surface of the collecting pipe 222. The distance between the bottom surface of the collecting pipe 222 and the bottom surface of the inner cavity of the reaction bed body 21 is 30 cm.

[0082] Example 2

[0083] This embodiment provides a modular reentry wetland device, which differs from Embodiment 1 in that the plants selected for the water purification biological layer on the reaction bed body include not only emergent plants with strong water purification ability such as reeds and calamus, but also emergent plants with ornamental value such as irises and lilies. The rest of the structure is exactly the same as Embodiment 1.

[0084] Example 3

[0085] This embodiment provides a modular wetland device, which is different from the first embodiment in that no upper flow guide wall and no lower flow guide wall are provided in the reaction bed body, and the rest of the structure is exactly the same as the first embodiment.

[0086] Comparative Example 1

[0087] This comparative example provides a modular return wetland device, which differs from Example 1 in that the mesh diameters of the hollow mesh surfaces of the rectangular frames in the first modular filler, the second modular filler and the third modular filler are all 3 cm, the particle size of the porous expanded clay is 40 to 80 mm, and the rest of the structure is exactly the same as Example 1.

[0088] Comparative Example 2

[0089] This comparative example provides a modular return wetland device, which differs from Example 1 in that the mesh apertures of the hollow mesh surface of the rectangular frame in the first modular filler, the second modular filler and the third modular filler are all 1.5 cm, the particle size of the porous expanded clay is 20 to 40 mm, and the rest of the structure is exactly the same as Example 1.

[0090] Comparative Example 3

[0091] This comparative example provides a modular reentry wetland device, which differs from Example 1 in that the water distribution unit is not provided with a secondary water distribution module, and the water distribution channel directly passes through the diversion pipes of multiple reaction bed bodies, and the rest of the structure is exactly the same as Example 1.

[0092] Application Example 1

[0093] This application example uses the modular return wetland device provided in Example 1 to test slightly polluted river water, and the inlet water quality and outlet water quality are shown in Table 1. The inlet water is sampled from the water distribution area, and the outlet water is sampled from the outlet channel.

[0094] Table 1

[0095] sample CODcr(mg / L) <![CDATA[NH3-N(mg / L)]]> TP(mg / L) Water Intake 35～70 0.80～2.60 0.15～0.60 Water 15～35 0.20～0.50 0.08～0.30

[0096] It is not difficult to see from Table 1 that the present invention uses a modular return wetland device to purify slightly polluted river water through an up and down return flow subsurface wetland, and the effluent water quality is better.

[0097] Application Example 2

[0098] This application example uses the modular reentry wetland device provided in Example 2 to test the tail water of a municipal sewage treatment plant, and the inlet water quality and outlet water quality are shown in Table 2. The inlet water is sampled from the water distribution area, and the outlet water is sampled from the outlet channel.

[0099] Table 2

[0100] sample CODcr(mg / L) <![CDATA[NH3-N(mg / L)]]> TP(mg / L) Water Intake 25～40 0.60～1.80 0.20～0.35 Water 15～35 0.20～0.80 0.08～0.21

[0101] It is not difficult to see from Table 2 that the present invention uses a modular return wetland device to purify the tail water of the sewage treatment plant through a submerged flow wetland with upward and downward return flow directions, and the effluent water quality is better.

[0102] Application Example 3

[0103] This application example uses the wetland device provided in Example 3 to test slightly polluted river water, and the inlet water quality and outlet water quality are shown in Table 3. The inlet water is sampled from the water distribution area, and the outlet water is sampled from the outlet channel.

[0104] Table 3

[0105]

[0106]

[0107] It can be seen from Table 3 that the effluent effect of Application Example 3 is lower than that of Application Example 1. This is mainly because in Example 1, the sewage flows through the reaction bed body in an up and down manner, which prolongs the residence time, allowing the sewage to fully contact and purify with the porous expanded clay, effectively improving the purification effect.

[0108] Comparative application example 1

[0109] This comparative application example uses the modular reentry wetland device provided in comparative example 1 to test slightly polluted river water, and the inlet water quality and outlet water quality are shown in Table 4. Among them, the inlet water is sampled from the water distribution area, and the outlet water is sampled from the outlet channel.

[0110] Table 4

[0111] sample CODcr(mg / L) <![CDATA[NH3-N(mg / L)]]> TP(mg / L) Water Intake 35～70 0.80～2.60 0.15～0.60 Water 20～45 0.30～0.55 0.10～0.40

[0112] It can be seen from Table 4 that the fillers used in the water inlet zone, reaction zone and water collection zone of the reaction bed body used in Comparative Example 1 are the same, and the filler size in the reaction zone is larger than that in Example 1, resulting in a decrease in the sewage treatment effect.

[0113] Comparative Application Example 2

[0114] This comparative application example uses the modular return wetland device provided in Comparative Example 2 to test slightly polluted river water, and its inlet water quality and outlet water quality are shown in Table 5. Among them, the inlet water is sampled from the water distribution area, and the outlet water is sampled from the outlet channel.

[0115] Table 5

[0116] sample CODcr(mg / L) <![CDATA[NH3-N(mg / L)]]> TP(mg / L) Water Intake 35～70 0.80～2.60 0.15～0.60 Water 20～55 0.35～0.75 0.10～0.40

[0117] It can be seen from Table 5 that, compared with Example 1, the fillers used in the water inlet zone, reaction zone and water collection zone of the reaction bed body adopted in Comparative Example 2 are the same, and the filler size is small, which is easy to be blocked, affecting the effluent water quality.

[0118] Comparative Application Example 3

[0119] This comparative application example uses the modular return wetland device provided in comparative example 3 to test slightly polluted river water, and its inlet water quality and outlet water quality are shown in Table 6. Among them, the inlet water is sampled from the water distribution area, and the outlet water is sampled from the outlet channel.

[0120] Table 6

[0121] sample CODcr(mg / L) <![CDATA[NH3-N(mg / L)]]> TP(mg / L) Water Intake 35～70 0.80～2.60 0.15～0.60 Water 18～40 0.25～0.55 0.08～0.40

[0122] It can be seen from Table 6 that, compared with Example 1, Comparative Example 3 only uses a connected water distribution channel for one water distribution, which makes the sewage entering the multiple reaction bed bodies unevenly distributed and prone to blockage, affecting the effluent quality.

[0123] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A modular return wetland device, characterized in that: The modular return wetland device comprises a water distribution unit, a wetland reaction unit and a drainage unit which are sequentially arranged along the water flow direction; The water distribution unit comprises a primary water distribution module and a secondary water distribution module connected in sequence; The wetland reaction unit includes a plurality of reaction bed bodies arranged side by side, the reaction bed body includes a water inlet area, a reaction area and a water collection area connected in sequence, the water inlet area is connected to the secondary water distribution module, and the water collection area is connected to the drainage unit; The water inlet area, the reaction area and the water collection area are respectively provided with a first modular filler, a second modular filler and a third modular filler, and the first modular filler, the second modular filler and the third modular filler are different from each other.

2. The modular return wetland device according to claim 1, characterized in that: The first modular filler, the second modular filler and the third modular filler independently include a plurality of rectangular frames, the rectangular frames are wrapped with hollow mesh surfaces, and the rectangular frames are filled with reactive fillers; The average particle sizes of the reactive fillers in the first modular filler, the second modular filler and the third modular filler are different from each other; The mesh apertures of the hollow mesh surfaces of the first modular filler, the second modular filler and the third modular filler are different from each other; Preferably, the rectangular frame and the reaction bed body, as well as two adjacent rectangular frames, are detachably connected.

3. The modular return wetland device according to claim 2, characterized in that: The average particle size of the reactive filler in the first modular filler is recorded as the first particle size, the average particle size of the reactive filler in the second modular filler is recorded as the second particle size, and the average particle size of the reactive filler in the third modular filler is recorded as the third particle size; The first particle size and the third particle size are independently larger than the second particle size; The first particle size is the same as or different from the third particle size; Preferably, the first particle size and the third particle size are independently 40 to 100 mm; Preferably, the second particle size is 10 to 40 mm; Preferably, the reactive filler comprises porous ceramsite.

4. The modular return wetland device according to claim 2 or 3, characterized in that: The mesh aperture of the hollow mesh surface of the first modular filler is recorded as the first aperture, the mesh aperture of the hollow mesh surface of the second modular filler is recorded as the second aperture, and the mesh aperture of the hollow mesh surface of the third modular filler is recorded as the third aperture; The first aperture and the third aperture are independently larger than the second aperture; The first aperture is the same as or different from the third aperture; Preferably, the first aperture and the third aperture are independently 3 to 6 cm; Preferably, the second aperture is 1-3 cm.

5. The modular return wetland device according to claim 1, characterized in that: A water purification biological layer is arranged on the top of the first modular filler, the second modular filler and the third modular filler; Preferably, the plants in the water purification biological layer include any one of reed, cattail, calamus, iris, loosestrife, lily or canna, or a combination of at least two of them.

6. The modular return wetland device according to claim 1, characterized in that: The primary water distribution module includes a water distribution channel, and the secondary water distribution module includes a plurality of water distribution channels arranged side by side, the water distribution channels correspond to the reaction bed body one by one, and the water distribution channels are connected to the reaction bed body; The inlet end of the water distribution channel is provided with a downward opening weir gate, and the water distribution channel is connected to the water distribution channel through the downward opening weir gate; Preferably, a first inspection hole is provided on the top of the water distribution channel, and a first grille cover is laid on the first inspection hole; Preferably, the inlet end of the water distribution channel is also provided with a main water injection pipe; Preferably, a shunt pipe is provided at the inlet end of the reaction bed body, and the shunt pipe is connected to the water distribution channel; Preferably, a plurality of first communication holes are distributed on the surface of the shunt pipe; Preferably, a plurality of first exhaust holes are provided on the top surface of the diverter pipe; Preferably, the distance between the bottom surface of the diverter pipe and the bottom surface of the inner cavity of the reaction bed body is 20-30 cm.

7. The modular return wetland device according to claim 1, characterized in that: The drainage unit includes a plurality of water outlet channels, each of which corresponds to the reaction bed body one by one, and the inlet end of each water outlet channel is connected to the reaction bed body; Preferably, a second inspection hole is provided at the top of the water outlet channel, and a second grille cover is laid on the second inspection hole; Preferably, a main drainage pipe is provided at the outlet end of the drainage unit, and the main drainage pipe is connected to a plurality of the outlet channels respectively; Preferably, a telescopic pipe is further provided inside the water outlet channel, one end of the telescopic pipe is connected to the inlet of the main drainage pipe, and the other end of the telescopic pipe is freely telescopic in a direction perpendicular to the water flow; Preferably, a manifold is provided at the outlet end of the reaction bed body, and the manifold is connected to the outlet channel; Preferably, a plurality of second communication holes are distributed on the surface of the collecting pipe; Preferably, a plurality of second exhaust holes are provided on the top surface of the manifold; Preferably, the distance between the bottom surface of the header and the bottom surface of the inner cavity of the reaction bed body is 20-30 cm.

8. The modular return wetland device according to claim 1, characterized in that: A plurality of upper flow guiding partition walls and a plurality of lower flow guiding partition walls extending perpendicular to the water flow direction are arranged in the reaction bed body, and the upper flow guiding partition walls and the lower flow guiding partition walls are arranged alternately and spaced apart along the water flow direction; A first guide port is provided at the top of the upper guide partition wall, and a second guide port is provided at the bottom of the lower guide partition wall, so that the water flow in the reaction bed body is baffled upward and downward; a first modular filler, a second modular filler or a third modular filler is provided between the adjacent upper guide partition wall and the lower guide partition wall; Preferably, the water inlet area is formed between the inlet end of the reaction bed body and the upper flow guide partition wall or the lower flow guide partition wall located at the front end; the water collection area is formed between the outlet end of the reaction bed body and the upper flow guide partition wall or the lower flow guide partition wall located at the rear end, and the remaining upper flow guide partition walls and the lower flow guide partition walls are alternately arranged in the reaction area; Preferably, the volume of the reaction zone is 4 to 8 times the volume of the water inlet zone.

9. The modular return wetland device according to claim 1, characterized in that: The bottom of the reactor bed body is also provided with an anti-seepage structure, the interior of the anti-seepage structure is provided with a cloth-membrane composite layer, and the cloth-membrane composite layer includes a first geotextile, a dense membrane and a second geotextile which are stacked in sequence; Preferably, the unit density of the first geotextile and the second geotextile is independently 300-400 g / m 2 ; Preferably, the thickness of the dense film is 0.5 to 1 mm; Preferably, the dense film is a HDPE film.

10. A sewage treatment system, characterized in that: The sewage treatment system comprises the modular reentry wetland device as described in any one of claims 1-9.

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