A modular backwash constructed wetland device

Abstract

The invention discloses a modular backwash artificial wetland device, in which aquatic plants are rooted in a coarse sand layer, a gravel layer is connected to a coarse sand layer and a medium gravel layer respectively, a large gravel layer is connected to a medium gravel layer and an LDPE liner respectively, a sewage inlet pipe and a backwash outlet pipe are installed on both sides of the coarse sand layer, a backwash inlet pipe and a sewage outlet pipe are installed on both sides below the large gravel layer and above the LDPE liner, and a first connecting ring and a second connecting ring are installed on both sides of the device respectively. Multiple modules are assembled in parallel or in series. The entire device has aquatic plants, a coarse sand layer, a small gravel layer, a medium gravel layer, a large gravel layer and an LDPE liner. The structure is simple, easy to use, and is a standard component. It can be industrially mass-produced, modularly assembled according to the actual number of users, and can be installed and used. The technical problem to be solved is to improve the domestic sewage treatment system in the process of new rural construction, better treat sewage, and meet the needs of rapid modernization construction in rural areas at this stage.

Description

Technical Field

[0001] The present invention belongs to the field of sewage treatment in rural construction, and more specifically relates to a modular backwashing artificial wetland device, which is suitable for the rapidly developing new rural construction and urban-rural integration process, and rural areas, towns, suburbs, etc. with incomplete sewage treatment supporting facilities. Background Art

[0002] With the rapid development of the economy, in the process of new rural construction and urban-rural integration, the living conditions in traditional rural areas, towns, suburbs, etc. have been improved day by day, but the corresponding supporting facilities have not been perfected. This has caused serious environmental problems, the most prominent of which is that domestic sewage containing various detergents and feces is discharged without treatment, and a large amount of it is discharged into ditches, ponds, lakes, and rivers, causing pollution of rivers and ponds, affecting the living environment and water safety of villagers. The lagging rural water treatment in my country restricts the overall process of water environment governance. Unlike cities, rural areas have small height differences and scattered houses, usually in strips or scattered points, which increases the difficulty of sewage collection. If the urban model is copied, the pipeline cost will also increase.

[0003] Usually, the houses of residents in these areas are far away from each other. If a sewage treatment plant is set up, large pumps are needed to pump sewage to the treatment plant, which will greatly increase the cost. If urban sewage treatment processes such as membrane bioreactors and large artificial wetlands are used, not only are the costs high and economically unbearable, but the technical requirements in the operation and maintenance process are also difficult to achieve. Therefore, it is particularly important to choose a treatment system that is suitable for the actual situation in the area.

[0004] Artificial wetlands are a common facility for treating sewage in my country. They have the advantages of good effluent quality, strong organic matter and ammonia nitrogen treatment capacity, convenient operation and maintenance, simple management, low investment and operation costs, etc. They are more suitable for small and medium-sized towns and villages with limited funds, energy shortages and lack of technical personnel. At present, artificial wetland systems are generally divided into horizontal flow, subsurface flow and vertical flow. Among them, vertical flow artificial wetlands are widely used because they have smaller footprints than other forms of wetlands, high treatment efficiency, and the entire system can be built completely underground. In vertical flow artificial wetlands, sewage percolates vertically from the surface to the bottom, and passes through different filler layers in the process of downward flow. The biofilm on the surface purifies the sewage, and it has a strong treatment capacity for aerobic organic matter in the wastewater. However, the existing vertical flow artificial wetlands are prone to compaction due to the highest sewage concentration at the top, which affects the water purification effect and often needs to be dredged, increasing the operation cost. Summary of the invention

[0005] The purpose of the present invention is to provide a modular backwashing artificial wetland device, which has a simple structure, is easy to use, low cost, efficient and easy to operate. The modularization of artificial wetlands is solved, a backwashing device is added to the module, and the existing artificial wetland sewage treatment system is improved, especially the problem of wetland blockage is solved, thereby better improving the sewage treatment effect.

[0006] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0007] A modular backwash artificial wetland device comprises aquatic plants, a coarse sand layer, a small gravel layer, a medium gravel layer, a large gravel layer, an LDPE lining layer, a sewage inlet pipe, a backwash inlet pipe, a backwash outlet pipe, a treated sewage discharge pipe, a first connecting ring and a second connecting ring, wherein the connection relationship is as follows: the aquatic plants are rooted in the coarse sand layer, the gravel layer is connected to the coarse sand layer and the medium gravel layer respectively, and the large gravel layer is connected to the medium gravel layer and the LDPE lining layer respectively (a small gravel layer, a medium gravel layer and a large gravel layer are sequentially stacked below the coarse sand layer); sewage inlet pipes and backwash outlet pipes are installed on both sides of the coarse sand layer for discharging sewage after backwashing, and backwash inlet pipes and treated sewage discharge pipes 10 are installed on both sides below the large gravel layer and above the LDPE lining layer for discharging treated sewage that meets the discharge standard. First, biological purification is carried out through aquatic plants, then physical sedimentation is carried out through the coarse sand layer, and then microbial degradation and biofilm adsorption are carried out through the small gravel layer, the medium gravel layer, and the large gravel layer. After these treatments, it is discharged horizontally from the sewage outlet pipe at the bottom. At this time, the sewage has been treated and settled layer by layer, reaching the Class A sewage treatment discharge standard in the national "Pollutant Discharge Standard for Urban Sewage Treatment Plants (GB18918-2002)", and is suitable for discharge into the natural environment. The LDPE lining 6 is an impermeable layer, which can prevent the entire device from leaking and polluting the environment, and can also extend the service life of the device. The first connecting ring and the second connecting ring are respectively installed on both sides of the entire device, which can be used for assembly of multiple modules and are suitable for the treatment of different sewage volumes.

[0008] The whole device is a single module, which is a cube with a side length of about 1m. According to the specific amount of sewage to be treated, multiple (4-8) modules can be assembled through the first connecting ring and the second connecting ring. Multiple modules can be assembled in parallel or in series. The assembled treatment system is placed in a large pit. Only aquatic plants can be seen from the surface, which will not affect the landscape. Except for aquatic plants, coarse sand layer, small gravel layer, medium gravel layer, large gravel layer and LDPE lining, all materials of the whole device are made of PVC.

[0009] The coarse sand layer is a water-permeable matrix and is required to contain aerobic or anaerobic microbial populations, and is usually coarse sand with a particle size of 0.1-6 mm.

[0010] The small gravel layer is usually volcanic rock with a diameter of 3-5cm. The volcanic rock biological filter material is a granular filter material made from volcanic rock ore through a series of processes such as mineral processing, crushing, screening, grinding, etc. The main components are minerals and trace elements. It appears as irregular particles, is porous and light, and is particularly suitable for microorganisms to grow and reproduce on its surface to form a biofilm.

[0011] The middle gravel layer is gravel with a diameter of 8-10 cm.

[0012] The large gravel layer is gravel with a diameter of 10-15 cm.

[0013] The thickness of the coarse sand layer is 20 cm;

[0014] The thickness of the small gravel layer is 30 cm;

[0015] The thickness of the medium gravel layer is 15 cm;

[0016] The thickness of the large gravel layer is 15 cm;

[0017] The thickness of the LDPE liner is 5 cm;

[0018] The aquatic plants are specifically common emergent plants, which are one or any combination of two to three of reeds, cannas, calamus, etc., which can not only play an adsorption role but also be used as ornamental plants.

[0019] Through the above technical measures, the most critical are the first connecting ring and the second connecting ring. These parts are not only important components for connecting standard components, but also their number (2-4), size (circle with a diameter of 10 cm) and firmness will directly affect the use effect. The second is the backwashing device, which is composed of a backwashing water inlet pipe and a backwashing water outlet pipe. This device is an innovation based on the wetland module currently in use on the market, which greatly enhances the sewage treatment effect and the service life of the module. This technology solves the problem of rural sewage treatment, and at the same time solves the problem of pollution caused by sewage being discharged into the nature without treatment. According to the actual situation, the specific problems in rural areas are solved, and a better sewage treatment effect is achieved without affecting the landscape effect. Compared with the previous artificial wetlands, it is better in sewage treatment effect, use effect, etc., and more practical, and can be assembled and backwashed, and it is also convenient to implement and replace.

[0020] Aquatic plants are mainly used for biological purification, the coarse sand layer is used for physical sedimentation, and the small gravel layer, medium gravel layer and large gravel layer are mainly used for microbial degradation and biofilm adsorption. The LDPE lining is an impermeable layer, which can prevent the entire device from leaking and polluting the environment, and can also extend the service life of the device. The first connecting ring and the second connecting ring mainly play a connecting role, connecting several (4-8) modules to treat different sewage volumes. The sewage inlet pipe is mainly used to collect sewage and discharge it into the device, and after treatment, the sewage is discharged through the sewage outlet pipe after treatment. The backwash inlet pipe and the backwash outlet pipe are backwashing devices, which are mainly used for backwashing after the coarse sand layer is compacted. Among them, the connecting ring can connect several (4-8) modules according to different sewage volumes, and the backwashing device increases the service life of the device.

[0021] Compared with the artificial wetlands that have been put into use before, this device has the following improvements: 1) It is a standardized module that can be assembled according to actual conditions (such as the number of users, sewage volume, pollution degree, etc.); 2) The newly added backwashing device can better improve the sewage treatment effect and extend the service life of the device; 3) Since microorganisms are the main body and core of artificial wetland pollution removal, and the small gravel layer in this device is volcanic rock with a diameter of 3-5cm, it is particularly suitable for microorganisms to grow and reproduce on its surface to form biofilm. It can enhance the adsorption of microorganisms in sewage and improve the sewage treatment effect.

[0022] Through the above technical measures, some simulation experiments were carried out on the device, and the following characteristics (conclusions) can be used as reference in practical applications:

[0023] (1) A single module can be used to treat domestic water for 1-3 households, two modules can be used for 3-6 households, and multiple modules can be assembled for 6 households or more to achieve the sewage treatment effect.

[0024] (2) A single module takes about 4 days to treat sewage and reach the discharge standard; two modules take about 3 days; and four modules take 2 days to reach the discharge standard. Therefore, the treatment time can also be considered in actual use.

[0025] (3) The device treats sewage and reduces the pollutant content in the sewage, reaching the first-level discharge standard of urban sewage (daily average value). Such as pH value (6-9), chemical oxygen demand (50mg / L), biochemical oxygen demand (10mg / L), suspended solids (10mg / L), animal and vegetable oils (1mg / L), petroleum (1mg / L), anionic surfactants (0.5mg / L), total nitrogen (15mg / L), ammonia nitrogen {5 (8mg / L) Note 5 is the control index when the water temperature is >12℃, 8 is the control index when the water temperature is ≤12℃}, total phosphorus (1mg / L), color (30 degrees), fecal coliform count (10 3 pieces / liter), etc.

[0026] Compared with the prior art, the present invention has the following advantages and effects:

[0027] The invention patent not only solves technical problems, but also reduces costs, improves sewage treatment effects, and improves the ecological environment. The device is simple and easy to operate. The core is a standard component with a side length of about 1m, which can be mass-produced and assembled according to the number and needs of users. Its frame and pipes are made of PVC material, which is low in cost, light, easy to transport, and simple to assemble.

[0028] This modular artificial wetland device can be effectively used for ten years (or more), saving a lot of costs during use. It is simple and easy to maintain. It only needs to regularly harvest and trim the aquatic plants, regularly replace the individual modules, and regularly backwash, which can well ensure the sewage treatment effect and landscape effect. It can be promoted and used in rural areas, towns and suburbs. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a modular backwash artificial wetland device.

[0030] Figure 2 It is a schematic diagram of the working of the device after a coarse sand layer becomes compacted.

[0031] Among them: 1-aquatic plants, 2-coarse sand layer, 3-small gravel layer, 4-medium gravel layer, 5-large gravel layer, 6-LDPE lining, 7-sewage inlet pipe, 8-backwash inlet pipe, 9-backwash outlet pipe, 10-sewage discharge pipe, 11-connecting ring and 12-connecting ring. DETAILED DESCRIPTION

[0032] Embodiment 1:

[0033] According to the following Figure 1 , Figure 2It can be seen that a modular backwash artificial wetland device is composed of aquatic plants 1, a coarse sand layer 2, a small gravel layer 3, a medium gravel layer 4, a large gravel layer 5, an LDPE lining 6, a sewage inlet pipe 7, a backwash inlet pipe 8, a backwash outlet pipe 9, a sewage discharge pipe 10, a first connecting ring 11 and a second connecting ring 12. It is characterized in that: the aquatic plants 1 are rooted in the coarse sand layer 2, the gravel layer 3 is connected (connected) to the coarse sand layer 2 and the medium gravel layer 4, and the large gravel layer 5 is connected (connected) to the medium gravel layer 4 and the LDPE lining 6, respectively (the small gravel layer 3, the medium gravel layer 4 and the large gravel layer 5 are stacked in sequence below the coarse sand layer 2). On both sides of the coarse sand layer 2, there are sewage inlet pipes 7 and backwash outlet pipes 9. On both sides under the large gravel layer 5 and above the LDPE lining 6, there are backwash inlet pipes 8 and treated sewage outlet pipes 10. On both sides of the (entire) device of the present invention, there are first connecting rings 11 and second connecting rings 12, respectively. Sewage enters the device from the sewage inlet pipe 7, is first biologically purified by aquatic plants 1, then physically precipitated through the coarse sand layer 2, and then microbial degradation and biofilm adsorption are carried out through the small gravel layer 3, the medium gravel layer 4, and the large gravel layer 5. After these treatments, it is horizontally discharged from the bottom of the sewage outlet pipe 10 outside the device. At this time, the sewage has been treated and precipitated layer by layer, reaching the Class A sewage treatment discharge standard in the national "Pollutant Discharge Standard for Urban Sewage Treatment Plants (GB18918-2002)", and is suitable for discharge into the natural environment. The LDPE lining 6 is an impermeable layer, which can prevent the entire device from leaking and polluting the environment, and can also extend the service life of the device. The first connecting ring 11 and the second connecting ring 12 are respectively installed on both sides of the whole device, which can be used for multiple modules to be assembled and is suitable for the treatment of different sewage volumes. This device also has a special design, namely the backwashing device (the device). Since the coarse sand layer 3 is easy to harden after the module has been used for a period of time, which affects the sewage purification effect, a backwashing device is set for treatment. The specific operation is to close the sewage inlet pipe 7 and the treated sewage outlet pipe 10, and then let the tap water enter the module from the backwashing inlet pipe 8. The water inlet pipe contains a pressure pump, and the pressure value is set (generally 20-30kpa). The pressurized tap water can reach the coarse sand layer 2, and the hardened sand layer can be backwashed to disperse it. After flushing, open the backwashing outlet pipe 9 to discharge the wastewater.

[0034] The (entire) device of the present invention is a single module, which is a cube, with a side length of about 1m, a width and a thickness of about 1m. According to the specific amount of sewage to be treated, multiple (generally 4-8) modules can be assembled through the first connecting ring 11 and the second connecting ring 12. The assembled treatment system is placed in a large pit, and only aquatic plants can be seen from the surface, which will not affect the landscape. Except for the aquatic plants 1, the coarse sand layer 2, the small gravel layer 3, the medium gravel layer 4, the large gravel layer 5 and the LDPE lining 6, all materials of the entire device are made of PVC.

[0035] The multiple modules (4-8) are stacked in sequence;

[0036] The coarse sand layer 2 is a water-permeable matrix and is required to contain aerobic or anaerobic microbial populations, and is usually coarse sand with a particle size of 0.1-6 mm (any particle size is acceptable).

[0037] The small gravel layer 3 is usually volcanic rock with a diameter of 3-5 cm (any diameter is acceptable). The volcanic rock biological filter material is a granular filter material made from volcanic rock ore through a series of processes such as mineral processing, crushing, screening, and grinding. Its main components are minerals and trace elements. It appears as irregular particles, is porous and light, and is particularly suitable for microorganisms to grow and reproduce on its surface to form a biofilm.

[0038] The middle gravel layer 4 is gravel with a diameter of 8-10 cm (any diameter is acceptable).

[0039] The large gravel layer 5 is gravel with a diameter of 10-15 cm (any diameter is acceptable).

[0040] The thickness of the coarse sand layer 2 is specifically 20 cm

[0041] The thickness of the small gravel layer 3 is specifically 30 cm

[0042] The thickness of the middle gravel layer 4 is specifically 15 cm

[0043] The thickness of the large gravel layer 5 is specifically 15 cm

[0044] The thickness of the LDPE liner 6 is specifically 5 cm.

[0045] The device has a simple structure, light materials, and is easy to use. It is a standard component that can be industrially mass-produced and modularly assembled according to the actual number of users, ready for use. The device is a vertical flow artificial wetland, which is the most commonly used artificial wetland type with the best sewage treatment effect, and a backwashing device is added. The technical problem to be solved is to improve the domestic sewage treatment system in the process of new rural construction, better treat sewage, and meet the needs of rapid modernization of rural areas at this stage.

[0046] First, based on the location of the user's house and the number of users who need to use the device, dig a large pit with a depth of 1m in the use area. According to the size of this sewage treatment pit (the length and width should preferably be an integer multiple of the side length), determine the number of modules to be used. After determining the number, assemble each module with a connecting ring and put it into the sewage treatment pit. Collect the sewage pipes of each household into one pipe and connect it to the sewage inlet pipe, and the device starts to operate. After running for a certain period of time (such as two months), harvest and prune the plants, and check the drainage effect of the outlet.

[0047] When the coarse sand layer 2 becomes compacted, Figure 2 If the coarse sand layer 2 is hardened, the backwash device (i.e., the backwash inlet pipe 8 and the backwash outlet pipe 9) is turned on to backwash the module to disperse the coarse sand layer. The specific operation is to close the sewage inlet pipe 7 and the treated sewage outlet pipe 10, and then let clean water enter the module from the backwash inlet pipe (8). The pressurized clean water reaches the surface of the coarse sand layer 2 from the bottom to disperse the hardened surface dirt. The dispersed dirt is discharged through the backwash outlet pipe 9.

[0048] Through the above specific embodiments, an improvement on the original rural sewage treatment is achieved, and the sewage treatment effect is better improved.

Claims

1. A modular backwash artificial wetland device for improving a domestic sewage treatment system, comprising aquatic plants (1), a coarse sand layer (2), a small gravel layer (3), a medium gravel layer (4), a large gravel layer (5), an LDPE lining (6), a sewage inlet pipe (7), a backwash inlet pipe (8), a backwash outlet pipe (9), a sewage outlet pipe (10), a first connecting ring (11) and a second connecting ring (12), characterized in that: Aquatic plants (1) are rooted in a coarse sand layer (2); a small gravel layer (3) is connected to the coarse sand layer (2) and a medium gravel layer (4) respectively; a large gravel layer (5) is connected to the medium gravel layer (4) and an LDPE lining layer (6) respectively; a sewage inlet pipe (7) and a backwash outlet pipe (9) are installed on both sides of the coarse sand layer (2); a backwash inlet pipe (8) and a sewage outlet pipe (10) are installed on both sides below the large gravel layer (5) and above the LDPE lining layer (6); and a first connecting ring (11) and a second connecting ring (12) are installed on both sides of the device respectively; A single module is a cube, with a side length of 1m, and a width and thickness of 1m. According to the specific amount of sewage to be treated and the treatment time required, 3 to 6 modules are assembled and stacked through a first connecting ring (11) and a second connecting ring (12), and the modules are assembled in parallel or in series. The assembled treatment system is placed in a large pit, and only aquatic plants can be seen from the surface, which will not affect the landscape. The frame and pipes of the module are made of PVC material. The first connecting ring (11) and the second connecting ring (12) play a connecting role, connecting several modules together to treat different amounts of sewage; the sewage inlet pipe (7) collects the sewage and discharges it into the device, and after treatment, the sewage is discharged through the treated sewage outlet pipe (10); the backwashing inlet pipe (8) and the backwashing outlet pipe (9) are backwashing devices, which are used for backwashing after the coarse sand layer is compacted; the small gravel layer (3) is volcanic rock with a diameter of 3-5 cm, which is suitable for microorganisms to grow and reproduce on its surface to form a biofilm; Wherein, the coarse sand layer (2) is a water-permeable matrix, which is coarse sand with a particle size of 0.1-6 mm, and the thickness of the coarse sand layer (2) is 20 cm; Wherein, the middle gravel layer (4) is gravel with a diameter of 8-10 cm, and the thickness of the middle gravel layer (4) is 15 cm; Wherein, the large gravel layer (5) is gravel with a diameter of 10-15 cm, and the thickness of the large gravel layer (5) is 15 cm; Wherein, the thickness of the LDPE lining (6) is 5 cm.

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