Rural sewage purification system and purification method

Abstract

The invention relates to the technical field of rural sewage treatment, in particular to a rural sewage purification system and method.The purification system comprises an ecological pond and a subsurface flow constructed wetland which are sequentially arranged in the water flow direction, and the ecological pond is used for pretreating rural sewage to obtain primary purified water; the subsurface flow constructed wetland is used for purifying the primary purified water again to obtain secondary purified water; the ecological pond comprises a first soil matrix, submerged plants, floating-leaved plants and first emergent aquatic plants which are sequentially arranged from bottom to top, and the submerged plants comprise warm-season submerged plants and cold-season submerged plants; the subsurface flow constructed wetland comprises a water distribution area, a reaction area, a second soil matrix and second emergent aquatic plants which are sequentially arranged from bottom to top; the first emergent aquatic plants and the second emergent aquatic plants comprise warm-season emergent aquatic plants and cold-season emergent aquatic plants. The artificial wetland filter material blockage can be effectively prevented, plants are alternately arranged in cold and warm seasons, plant death is reduced, and the system operation stability is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of rural sewage treatment, and in particular to a rural sewage purification system and a purification method. Background Art

[0002] As we all know, rural domestic sewage has three characteristics: dispersion, diversity and extensiveness. The collection of rural domestic sewage has always been a problem that cannot be achieved by centralized sewage treatment methods, usually subject to dual constraints of space and investment. Nowadays, there is still no perfect pipeline system in the village to collect sewage from each household for treatment. Therefore, rural domestic sewage is usually treated on-site with decentralized domestic sewage treatment technology.

[0003] In the existing technology, artificial wetlands are usually a better method for in-situ sewage treatment. Compared with traditional sewage treatment plants, they have the characteristics of low investment, low energy consumption, and low operating costs. This method mainly uses biotechnology to purify water quality, which produces less secondary pollution. In addition, artificial wetlands usually use aquatic plants as the main treatment plants, which can beautify the rural living environment to a certain extent. At the same time, artificial wetland treatment facilities have the advantages of adapting to local conditions, and the construction scale can be controlled, which is easy to maintain. Therefore, the use of artificial wetland methods to treat rural sewage has high flexibility and social and environmental benefits.

[0004] However, there are also certain drawbacks to the artificial wetland treatment method. A variety of fillers are usually placed in the artificial wetland system to achieve the purpose of filtering and removing related pollutants. During long-term use, the fillers are prone to blockage. In addition, in the face of alternating cold and warm weather, plants are prone to death, which will reduce the treatment efficiency of the artificial wetland system. Summary of the invention

[0005] The present invention provides a rural sewage purification system and a purification method, which are used to solve the defect of low treatment efficiency of rural sewage purification systems in the prior art and ensure high treatment efficiency.

[0006] The present invention provides a rural sewage purification system, comprising an ecological pond and a subsurface artificial wetland arranged in sequence along the water flow direction, wherein the ecological pond is used to pre-treat rural sewage to obtain primary purified water; the subsurface artificial wetland is connected to the ecological pond, and the subsurface artificial wetland is used to purify the primary purified water again to obtain secondary purified water; The ecological pond includes a first soil matrix, submerged plants, floating-leaf plants and a first emergent plant arranged in sequence from bottom to top, and the submerged plants include warm-season submerged plants and cold-season submerged plants; The subsurface artificial wetland includes a water distribution area, a reaction area, a second soil matrix and a second emergent plant arranged in sequence from bottom to top, and the first emergent plant and the second emergent plant both include warm season emergent plants and cold season emergent plants.

[0007] According to a rural sewage purification system provided by the present invention, the thickness of the first soil matrix is ​​at least 30 centimeters, and the thickness of the first soil matrix gradually increases from the middle to the edge of the ecological pond.

[0008] According to a rural sewage purification system provided by the present invention, the water depth of the ecological pond is 50-150 cm, the retention time is 2-4 days, and the hydraulic load is 0.20-0.50 m 3 / (m 2 ·d).

[0009] According to a rural sewage purification system provided by the present invention, the first emergent plant includes at least one of reed and rush, and the planting density is 10-20 plants / square meter.

[0010] According to a rural sewage purification system provided by the present invention, the floating leaf plants include water lilies, and the planting density of the water lilies is 1-3 plants / square meter.

[0011] According to a rural sewage purification system provided by the present invention, the warm season submerged plants include at least one of Myriophyllum paniculate, Ceratophyllum and Hydrilla verticillatum, and the planting density is 25-35 plants / square meter; the cold season submerged plants include Potamogeton crispus, and the planting density is 20-40 plants / square meter.

[0012] According to a rural sewage purification system provided by the present invention, one side of the subsurface artificial wetland is a water inlet, and the other side is a water outlet, a water inlet area is arranged vertically on the ground near the water inlet, the water inlet area and the water distribution area are both filled with gravel matrix, and the thickness of the water distribution area is greater than 10 cm.

[0013] According to a rural sewage purification system provided by the present invention, the reaction zone includes a plurality of packing layers, which are arranged in order from bottom to top as gravel, quartz sand and zeolite, and a stainless steel mesh is arranged between each adjacent packing layer.

[0014] According to a rural sewage purification system provided by the present invention, the warm-season emergent plants include reeds, and the cold-season emergent plants include water celery.

[0015] The present invention also provides a rural sewage purification method, using the rural sewage purification system as described in any one of the above items, comprising: The sewage is pre-treated in an ecological pond with a hydraulic retention time of 2-4 days to obtain primary purified water; The primary purified water enters a subsurface artificial wetland for treatment, with a hydraulic retention time of 2-4 days, to obtain secondary purified water.

[0016] The rural sewage purification system and purification method provided by the present invention sequentially arrange an ecological pond and a subsurface artificial wetland along the water flow direction; the ecological pond pre-treats the sewage to obtain primary purified water; the subsurface artificial wetland is connected to the ecological pond; the subsurface artificial wetland purifies the primary purified water again to obtain secondary purified water, thereby achieving the purpose of sewage treatment, improving the treatment effect of a single treatment unit, and effectively reducing the possibility of clogging of filter materials in the artificial wetland.

[0017] In addition, the submerged plants in the ecological pond include warm season submerged plants and cold season submerged plants; the emergent plants in the ecological pond include warm season emergent plants and cold season emergent plants, which can form an alternating cold and warm season aquatic plant purification system, greatly reducing the side effects of the death of plants planted in the ecological pond and submerged artificial wetland on the operation of the system, having a stronger ability to resist shock loads, alleviating the adverse effects of low temperature, and being able to effectively respond to the seasonal and temporal changes in the concentration of pollutants and water volume in rural sewage, improving the stability of the system operation, and thereby achieving the effect of stable treatment of rural sewage.

[0018] The present invention can be widely used in rural areas to carry out in-situ treatment of rural sewage that is difficult to collect and treat centrally. While meeting the rural sewage treatment effect, it can effectively increase the landscape of related areas and promote a harmonious and beautiful living environment.

[0019] In addition, better purification effects can be achieved only through ecological ponds and subsurface artificial wetlands. The process is simple, so the investment scale is small and the project cost is low. The entire system relies mostly on plants and microorganisms to remove pollutants, and there is no external power source, so the energy consumption is low.

[0020] Finally, the present invention can determine the land area according to the treatment scale and surrounding land use conditions, and is flexible in application, which has great development advantages in the field of decentralized rural sewage treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 It is a plan schematic diagram of the rural sewage purification system provided by the present invention.

[0023] Figure 2 It is a structural schematic diagram of the ecological pond provided by the present invention.

[0024] Figure 3 It is a structural schematic diagram of the subsurface flow artificial wetland provided by the present invention.

[0025] Reference numerals: 1. Ecological pond; 2. Submerged artificial wetland; 11. First soil matrix; 12. Submerged plants; 13. Floating-leaf plants; 14. First emergent plants; 21. Water distribution area; 22. Reaction area; 23. Second soil matrix; 24. Second emergent plants; 25. Water inlet; 26. Water outlet; 27. Water inlet area; 28. Stainless steel mesh. DETAILED DESCRIPTION

[0026] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0027] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0028] Combine the following Figure 1-Figure 3 The rural sewage purification system of the present invention comprises an ecological pond 1 and a subsurface artificial wetland 2 which are sequentially arranged along the water flow direction.

[0029] Among them, Eco-pond 1 is used for pre-treatment of rural sewage. It removes suspended matter, organic matter and some nutrients in sewage through natural ecological processes, reduces the burden for subsequent treatment, and obtains primary purified water.

[0030] The subsurface artificial wetland 2 is connected to the ecological pond 1. As a subsequent treatment unit of the ecological pond 1, the subsurface artificial wetland 2 deeply treats the primary purified water through more complex physical, chemical and biological processes to further improve the water quality and meet the discharge standards. The subsurface artificial wetland 2 is used to purify the primary purified water again to obtain secondary purified water.

[0031] Through the above arrangement, the treatment effect of a single treatment unit is improved, and the possibility of clogging of the filter material in the subsurface flow constructed wetland 2 is effectively reduced.

[0032] The ecological pond 1 includes a first soil matrix 11, a submerged plant 12, a floating leaf plant 13 and a first emergent plant 14 arranged in sequence from bottom to top, and the submerged plant 12 includes a warm season submerged plant and a cold season submerged plant; The subsurface artificial wetland 2 includes a water distribution area 21, a reaction area 22, a second soil matrix 23 and a second emergent plant 24 arranged in sequence from bottom to top. The first emergent plant 14 and the second emergent plant 24 both include warm season emergent plants and cold season emergent plants.

[0033] The present invention configures the plant species planted in the ecological pond 1 and the subsurface artificial wetland 2 to establish an aquatic plant purification system that alternates between warm and cold seasons, thereby ensuring the plant quantity of the subsurface artificial wetland 2 during operation, greatly reducing the side effects caused by the death of plants planted in the ecological pond 1 and the subsurface artificial wetland 2, having a stronger ability to resist shock loads, alleviating the adverse effects of low temperatures, and being able to effectively respond to the seasonal and temporal changes in the concentration of pollutants and the amount of water in rural sewage, thereby improving the stability of the system operation.

[0034] Among them, the first soil matrix 11 is the bottom base layer of the ecological pond, which is usually a mixture of various soils and possible organic matter, providing the necessary microbial habitat and nutritional support for the entire system. The soil matrix can adsorb, filter and decompose some pollutants in the water body. In a feasible embodiment of the present invention, the thickness of the first soil matrix 11 is at least 30 cm, and the thickness of the first soil matrix 11 gradually increases from the middle to the edge of the ecological pond 1. The first soil matrix 11 can be raised to 50 cm near the edge of the ecological pond 1 to facilitate the planting of the first emergent plant 14.

[0035] In a feasible embodiment of the present invention, the water depth of the ecological pond 1 is 50-150 cm, the retention time is 2-4 days, and the hydraulic load is 0.20-0.50 m3 / (m 2 ·d). The water treated in the ecological pond 1 flows through the pipeline to the subsurface artificial wetland 2 for the next treatment.

[0036] In a feasible embodiment of the present invention, the first emergent plant 14 includes at least one of reed and rush, and the planting density is 10-20 plants / square meter. The water depth suitable for the growth of reed is 30-50cm, it is widely distributed, has strong stress resistance, a long growth cycle and a large biomass, a high total nitrogen removal rate, and can withstand certain wind and waves. The water depth suitable for the growth of rush is 10-15cm, it can have a good removal effect on ammonia nitrogen and Kjeldahl nitrogen in water, and it has a strong ability to resist diseases and insect pests.

[0037] In a feasible embodiment of the present invention, the floating leaf plants 13 include water lilies, and the planting density of the water lilies is 1-3 plants / square meter. The water lily roots can absorb toxic substances such as mercury, lead, phenol, etc. in the water, and can also filter microorganisms in the water. At the same time, they can withstand low temperatures and are not easy to die in winter. At the same time, they can bloom and increase the aesthetics.

[0038] In a feasible embodiment of the present invention, the warm season submerged plants include at least one of Myriophyllum paniculate, Ceratophyllum and Hydrilla verticillatum, and the planting density is 25-35 plants / square meter; the cold season submerged plants include Potamogeton crispus, and the planting density is 20-40 plants / square meter. The submerged plants 12 are completely submerged in the water, absorbing nutrients in the water through their roots, while their lush branches and leaves can reduce water disturbance, promote the sedimentation of suspended matter in the water, and help improve water transparency. The combination of warm season and cold season plants ensures that the ecological pond can maintain a high ecological activity in different seasons.

[0039] Among them, the growth cycle of Myriophyllum spicateum is relatively long, and it has a good effect on nitrogen and phosphorus removal, especially it has a high removal efficiency for various forms of nitrogen; Dermatophyllum is a typical pollution-tolerant species, which can remove a certain amount of suspended sediment with smaller particles, and can play a certain role in preventing blockage of artificial wetlands. It has a more significant effect on the removal of inorganic nitrogen, and can inhibit the spread of Myriophyllum spicateum, which helps to form a more balanced aquatic ecosystem; Hydrilla verticillata can absorb adsorbed phosphorus and reduced phosphorus, and can effectively filter fine suspended particles, and can also play a role in filtering water quality; Water Chestnut is a relatively rare off-season aquatic plant, which can form a cold and warm season alternating aquatic plant purification system with warm season aquatic plants to alleviate the adverse effects of low temperature, thereby achieving the purpose of effectively removing pollutants.

[0040] In addition, the water depth of the subsurface artificial wetland 2 is usually set at 5-10 cm and the hydraulic load is 0.30-0.80 m 3 / (m 2 ·d) The hydraulic retention time is 2-4 days.

[0041] In a feasible embodiment of the present invention, one side of the subsurface artificial wetland 2 is a water inlet 25, and the other side is a water outlet 26. A water inlet area 27 is arranged vertically on the ground near the water inlet 25. The water inlet area 27 and the water distribution area 21 are both filled with gravel matrix. The gravel diameter of the water inlet area 27 is usually selected to be 40-80mm, and the thickness of the water distribution area 21 is greater than 10 cm to prevent the filler in the reaction zone 22 from clogging the perforated pipe.

[0042] It should be noted that a perforated pipe may be generally provided in the water distribution area 21 , and the perforated pipe runs through the width of the subsurface flow constructed wetland 2 to ensure uniform water distribution.

[0043] In a feasible embodiment of the present invention, the reaction zone 22 includes multiple packing layers, which are arranged in order from bottom to top as gravel, quartz sand and zeolite, and in order to prevent different packing layers from sinking, especially the packing layer with smaller particles from sinking, a stainless steel mesh 28 is arranged between each adjacent packing layer. More specifically, the pore size of the stainless steel mesh 28 can be selected to be 2 mm. Finally, a 30-40 cm thick soil matrix is ​​covered on the reaction zone 22 for plant planting.

[0044] In a feasible embodiment of the present invention, the warm-season emergent plants include reeds, and the cold-season emergent plants include water celery. The planting density of water celery is 10-20 plants / square meter.

[0045] A second aspect of the present invention provides a method for purifying rural sewage, wherein the rural sewage purification system as described in any of the above embodiments comprises: S1. The sewage is pre-treated in the ecological pond 1 to obtain primary purified water.

[0046] At this stage, rural sewage is first introduced into the Eco-pond 1 system. Eco-pond 1 uses the purification capacity of the natural ecosystem to remove suspended solids, some organic matter, nitrogen, phosphorus and other pollutants in sewage through the decomposition of microorganisms, the absorption of aquatic plants, and the physical processes of natural sedimentation and filtration of water bodies, thereby obtaining primary purified water.

[0047] Since the submerged plants in the ecological pond 1 include warm season submerged plants and cold season submerged plants, and the emergent plants in the ecological pond include warm season emergent plants and cold season emergent plants, a cold-warm season alternating aquatic plant purification system can be formed, which greatly reduces the side effects of the death of plants planted in the ecological pond and submerged flow artificial wetland on the operation of the system, has a stronger ability to resist shock loads, alleviates the adverse effects of low temperature, can effectively respond to the seasonal and temporal changes in the concentration of pollutants and water volume in rural sewage, improves the stability of the system operation, and then achieves the effect of stable treatment of rural sewage.

[0048] Ecological Pond 1 uses biological and physical processes in nature for purification, without the need for large amounts of energy and chemicals, and is low-cost and environmentally friendly. Aquatic plants can be planted in Ecological Pond 1 to increase biodiversity and form a virtuous cycle ecosystem. It can effectively remove most suspended solids and easily degradable organic matter in sewage, reducing the burden on subsequent treatment.

[0049] S2, the primary purified water enters the subsurface artificial wetland 2 for treatment to obtain secondary purified water.

[0050] The primary purified water after pretreatment in Eco-pond 1 is then introduced into the subsurface artificial wetland system for deep treatment. Subsurface artificial wetland 2 further removes and transforms the remaining pollutants in the water through its unique matrix layer (such as soil, gravel, etc.), plant root system and microbial community, and finally obtains high-quality secondary purified water.

[0051] Subsurface artificial wetland 2 can effectively remove refractory organic matter, nitrogen, phosphorus and other nutrients in water, and improve the quality of effluent. Subsurface artificial wetland 2 has strong buffering and self-regulation capabilities, which can ensure the stability and reliability of effluent water quality. Subsurface artificial wetland 2 not only has purification function, but also beautifies the environment, becoming a landscape in rural areas.

[0052] The emergent plants in the subsurface artificial wetland 2 include warm season emergent plants and cool season emergent plants, which can also effectively respond to seasonal and temporal changes, improve the stability of system operation, and thus achieve the effect of stable treatment of rural sewage.

[0053] Therefore, the rural sewage purification method provided by the present invention combines the ecological pond 1 and the subsurface artificial wetland 2, which can effectively achieve the purpose of treating rural sewage, while improving the treatment effect of a single treatment unit, and effectively reducing the possibility of clogging of the filter material of the artificial wetland; and the planted plants are arranged alternately in cold and warm seasons, which greatly reduces the side effects of the death of plants planted in the ecological pond 1 and the subsurface artificial wetland 2 on the system, improves the stability of the system operation, and then achieves the effect of stable treatment of rural sewage.

[0054] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" 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 an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0055] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A rural sewage purification system, characterized in that: The invention comprises an ecological pond (1) and a subsurface artificial wetland (2) which are arranged in sequence along the water flow direction, wherein the ecological pond (1) is used for pre-treating rural sewage to obtain primary purified water; the subsurface artificial wetland (2) is connected to the ecological pond (1), and the subsurface artificial wetland (2) is used for re-purifying the primary purified water to obtain secondary purified water; The ecological pond (1) comprises a first soil matrix (11), submerged plants (12), floating-leaf plants (13) and a first emergent plant (14) arranged in sequence from bottom to top, wherein the submerged plants (12) comprise warm-season submerged plants and cold-season submerged plants; The subsurface artificial wetland (2) comprises a water distribution area (21), a reaction area (22), a second soil matrix (23) and a second emergent plant (24) which are arranged in sequence from bottom to top, and the first emergent plant (14) and the second emergent plant (24) both comprise warm-season emergent plants and cold-season emergent plants.

2. The rural sewage purification system according to claim 1, characterized in that: The thickness of the first soil matrix (11) is at least 30 centimeters, and the thickness of the first soil matrix (11) gradually increases from the middle to the edge of the ecological pond (1).

3. The rural sewage purification system according to claim 1, characterized in that: The water depth of the ecological pond (1) is 50-150 cm, the retention time is 2-4 days, and the hydraulic load is 0.20-0.50 m 3 / (m 2 ·d).

4. The rural sewage purification system according to claim 1, characterized in that: The first emergent plant (14) comprises at least one of reed and rush, and the planting density is 10-20 plants / square meter.

5. The rural sewage purification system according to claim 1, characterized in that: The floating leaf plants (13) include water lilies, and the planting density of the water lilies is 1-3 plants / square meter.

6. The rural sewage purification system according to claim 1, characterized in that: The warm-season submerged plants include at least one of Myriophyllum paniculate, Ceratophyllum demersum and Hydrilla verticillatum, and the planting density is 25-35 plants / square meter; the cold-season submerged plants include Potamogeton crispus, and the planting density is 20-40 plants / square meter.

7. The rural sewage purification system according to claim 1, characterized in that: One side of the subsurface artificial wetland (2) is a water inlet (25), and the other side is a water outlet (26). A water inlet area (27) is arranged vertically on the ground near the water inlet (25). Both the water inlet area (27) and the water distribution area (21) are filled with gravel matrix, and the thickness of the water distribution area (21) is greater than 10 centimeters.

8. The rural sewage purification system according to claim 1, characterized in that: The reaction zone (22) comprises a plurality of packing layers, which are arranged in order from bottom to top as gravel, quartz sand and zeolite, and a stainless steel mesh (28) is arranged between each adjacent packing layer.

9. The rural sewage purification system according to claim 1, characterized in that: The warm season emergent plants include reeds, and the cool season emergent plants include water celery.

10. A rural sewage purification method, using the rural sewage purification system according to any one of claims 1 to 9, characterized in that: include: The sewage is pre-treated in an ecological pond (1) with a hydraulic retention time of 2-4 days to obtain primary purified water; The primary purified water enters the subsurface artificial wetland (2) for treatment, with a hydraulic retention time of 2-4 days, to obtain secondary purified water.

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