Distributed rural domestic sewage treatment system

Abstract

The utility model relates to a distributed rural domestic sewage treatment system which comprises a first regulating tank, a second regulating tank, an aerobic tank, a second anoxic tank and a downstream subsurface flow constructed wetland which are sequentially communicated along the water flow direction of grey water, and a third regulating tank and a first anoxic tank which are communicated along the water flow direction of black water, water flow in the first anoxic tank flows into the second anoxic tank through the one-way valve, water flow in the first regulating tank flows into the second regulating tank through the coarse screen, water flow in the second regulating tank flows into the aerobic tank through the fine screen, and water flow in the third regulating tank flows into the first anoxic tank through the fine screen. The device has the beneficial effects that a mode that black water and grey water enter separately and are finally mixed in the second anoxic tank is adopted, a carbon source in the black water can be fully utilized to effectively reduce high-concentration nitrogen and phosphorus in the black water, the mixed water finally flows to the downstream subsurface flow constructed wetland, pollutants are further reduced, a gravity self-flowing mode is adopted in the whole process, and the pollution to the environment is reduced. And obvious energy-saving and consumption-reducing effects are achieved.

Description

Technical Field

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

[0002] With the gradual resolution of point source pollution problems, non-point source pollution has become the focus and difficulty of my country's water environment governance at present and in the future, and rural domestic sewage treatment has become one of the main factors restricting non-point source pollution control. According to relevant data statistics, the total amount of village and town sewage discharge in 2020 reached 33.71 billion tons, but the sewage treatment rate was only about 31%, and the remaining nearly 69% were directly discharged into the surrounding receiving water bodies. The existing urban sewage treatment process is not suitable for use in rural areas with a small total amount of sewage, scattered economic conditions, and lack of technology. Therefore, it is of great significance to develop a decentralized sewage treatment process for rural areas with stable water standards, low energy consumption, and simple operation and management to strengthen domestic sewage treatment in rural areas.

[0003] Rural domestic sewage is rich in elements such as nitrogen, phosphorus and potassium. The excessive presence of these substances will cause a certain degree of pollution to the water body, but they are essential fertilizers for agricultural production. In recent years, the concept of resource utilization of rural domestic sewage has continued to deepen. The "Guiding Opinions on Promoting the Resource Utilization of Sewage" issued in 2021 emphasized the need to "steadily promote the resource utilization of agricultural and rural sewage."

[0004] Therefore, exploring a sewage treatment process that is efficient, low-consumption and can recycle resources has important practical significance for controlling rural environmental pollution and building beautiful villages. Utility Model Content

[0005] The technical problem to be solved by the utility model is to provide a decentralized rural domestic sewage treatment system to overcome the deficiencies in the above-mentioned prior art.

[0006] The utility model solves the above-mentioned technical problem with the following technical solution: a decentralized rural domestic sewage treatment system, comprising: a first regulating tank, a second regulating tank, an aerobic tank, a second anoxic tank and a downward submerged artificial wetland connected in sequence along the gray water flow direction, and a third regulating tank and a first anoxic tank connected along the black water flow direction, the water in the first anoxic tank flows into the second anoxic tank through a one-way valve, the water in the first regulating tank flows into the second regulating tank through a coarse grid, the water in the second regulating tank flows into the aerobic tank through a fine grid, and the water in the third regulating tank flows into the first anoxic tank through a fine grid.

[0007] The beneficial effects of the utility model are:

[0008] 1) The black water and grey water enter separately. The grey water flows through the first regulating tank, the second regulating tank, the aerobic tank and the second anoxic tank in sequence. The grey water flows through the third regulating tank, the first anoxic tank and the second anoxic tank in sequence. That is, the black water and the grey water are finally mixed in the second anoxic tank, which can make full use of the carbon source in the black water to effectively reduce the high concentration of nitrogen and phosphorus in the black water without artificially supplementing the carbon source, and has obvious effects of improving quality and increasing efficiency. In addition, the mixture in the second anoxic tank finally flows to the downward submerged artificial wetland, which further reduces pollutants, reduces and adsorbs heavy metals and antibiotics, and achieves a good comprehensive pollutant reduction effect. The first anoxic tank is used to extend the flow path of the black water and strengthen the anoxic biochemical effect;

[0009] 2) The entire treatment system adopts gravity flow throughout the process, which has obvious energy-saving and consumption-reducing effects;

[0010] 3) The downward subsurface flow artificial wetland has a strengthening effect on pollutant reduction. During the fertilization and irrigation season, when the crops have a great demand for fertility, water can be taken from the outlet of the second anoxic pool for irrigation. When the crops have a small demand for fertility, water can be taken from the outlet of the downward subsurface flow artificial wetland for irrigation. In the non-irrigation season, domestic sewage is systematically treated and discharged into the surrounding receiving water bodies after passing through the downward subsurface flow artificial wetland. The effluent from the downward subsurface flow artificial wetland meets both the farmland irrigation water quality standards and the urban sewage discharge water quality standards. The effluent from the second anoxic pool meets the farmland irrigation water quality standards.

[0011] On the basis of the above technical solution, the present invention can also be improved as follows.

[0012] Furthermore, the grid spacing of the coarse grid is 8 mm to 12 mm, and the grid spacing of the fine grid is 4 mm to 6 mm.

[0013] Furthermore, the pool capacity of the second regulating pool is larger than the pool capacity of the first regulating pool.

[0014] The above method has the further beneficial effect that the hydraulic retention time in the second regulating tank is longer, so that the pollutants in the gray water to be introduced into the aerobic tank can be initially reduced and the water quality and quantity can be adjusted.

[0015] Furthermore, guide plates are suspended in the first regulating tank, the second regulating tank and the third regulating tank, and baffles are arranged in the first anoxic tank.

[0016] The further beneficial effects of adopting the above are: the guide plates in the first regulating tank, the second regulating tank and the third regulating tank are beneficial to the precipitation of heavy particles or residues on the one hand, and on the other hand, extend the water flow path to pre-treat and reduce pollutants to a certain extent; the baffles in the first anoxic tank can extend the water flow path to effectively reduce nitrate nitrogen, total phosphorus, organic matter, etc.

[0017] Furthermore, an aeration plate is arranged at the bottom of the aerobic tank, the dissolved oxygen content in the aerobic tank is 4mg / L-5mg / L, and the dissolved oxygen content in the second anoxic tank and the first anoxic tank is 1mg / L-2mg / L.

[0018] The above method has the further beneficial effect that the aerobic pool can be aerated and oxygenated to maintain its oxygen content within the target value range, and only the aeration disk consumes electrical energy in the entire system.

[0019] Furthermore, rope-shaped artificial aquatic plants are arranged in the aerobic pool, the second anoxic pool and the first anoxic pool.

[0020] The above further beneficial effects are: using the biofilm method to reduce pollutants, compared with the activated sludge method, the system has stronger impact resistance, faster biofilm startup, better pollutant reduction effect, and less sludge production.

[0021] Furthermore, the spacing between the rope-shaped artificial aquatic plants is 15 cm to 20 cm.

[0022] Furthermore, the bottom sand layer of the downward subsurface flow artificial wetland is mixed with slow-release carbon sources and anoxic and facultative microbial agents.

[0023] Furthermore, the downward subsurface flow artificial wetland is an unsaturated artificial wetland, and the unsaturated ratio is 50%.

[0024] The beneficial effects of adopting the above two steps are as follows: the lower half of the wetland is flooded, which is conducive to the survival of anoxic anaerobic microorganisms, while the upper half of the wetland is free of water, which is conducive to the survival of aerobic microorganisms. That is, the downward partially unsaturated artificial wetland can first carry out aerobic biochemical reactions on the treated mixed water, and then carry out anoxic and anaerobic biochemical reactions. Ammonia nitrogen can be effectively treated in the upper half of the wetland, while nitrate nitrogen is mainly reduced in the lower half of the wetland. The wetland can also further reduce total phosphorus and COD, and can also play a certain reduction effect on antibiotics, heavy metals, etc., and has a high ecological value.

[0025] Furthermore, the first regulating tank and the second regulating tank share a common wall, and the common wall has a hole connecting the first regulating tank with the second regulating tank, and the coarse grid between the first regulating tank and the second regulating tank is arranged in the hole on the common wall; the second regulating tank and the aerobic tank share a common wall, and the common wall has a hole connecting the second regulating tank with the aerobic tank, and the fine grid between the second regulating tank and the aerobic tank is arranged in the hole on the common wall; the third regulating tank and the first anoxic tank share a common wall, and the common wall has a hole connecting the third regulating tank with the first anoxic tank, and the fine grid between the third regulating tank and the first anoxic tank is arranged in the hole on the common wall. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1It is the plan layout diagram of the decentralized rural domestic sewage treatment system in the utility model;

[0027] Figure 2 This is a water flow diagram of the decentralized rural domestic sewage treatment system in the utility model.

[0028] In the accompanying drawings, the components represented by the reference numerals are listed as follows:

[0029] 1. The first regulating pond, 2. The second regulating pond, 3. The aerobic pond, 4. The second anoxic pond, 5. The downward subsurface artificial wetland, 6. The third regulating pond, 7. The first anoxic pond, 8. The coarse screen, 9. The fine screen, 10. The guide plate, 11. The aeration plate, 12. The rope-shaped artificial aquatic plants, 13. The baffle. DETAILED DESCRIPTION

[0030] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0031] Example 1

[0032] like Figure 1 , Figure 2 As shown, a decentralized rural domestic sewage treatment system comprises: a first regulating tank 1, a second regulating tank 2, an aerobic tank 3, a second anoxic tank 4, a downward submerged artificial wetland 5, a third regulating tank 6 and a first anoxic tank 7. The first regulating tank 1, the second regulating tank 2, the aerobic tank 3, the second anoxic tank 4 and the downward submerged artificial wetland 5 are sequentially connected along the gray water flow direction, the third regulating tank 6 is connected with the first anoxic tank 7 along the black water flow direction, the water in the first anoxic tank 7 flows into the second anoxic tank 4 through a one-way valve, that is, the flow direction of the one-way valve is from the first anoxic tank 7 to the second anoxic tank 4; the water in the first regulating tank 1 flows into the second regulating tank 2 through a coarse grid 8, the water in the second regulating tank 2 flows into the aerobic tank 3 through a fine grid 9, and the water in the third regulating tank 6 flows into the first anoxic tank 7 through a fine grid 9;

[0033] The workflow is as follows:

[0034] When the grey water enters the first regulating tank 1, the heavier and larger particles or residues in the grey water will be deposited on the bottom of the first regulating tank 1, and the lighter and finer particles or residues in the grey water will flow with the water flow to the coarse screen 8 between the first regulating tank 1 and the second regulating tank 2, while the lighter and finer particles or residues will be blocked by the coarse screen 8, and the filtered water will flow into the second regulating tank 2;

[0035] The second regulating pool 2 performs preliminary reduction of pollutants in the grey water and regulates the water quality and quantity. The water in the second regulating pool 2 flows to the fine grid 9 between the second regulating pool 2 and the aerobic pool 3, and the lighter and finer particles or residues in the grey water are further filtered out by the fine grid 9. The filtered water flows into the aerobic pool 3, and the particles or residues in the first regulating pool 1 and the second regulating pool 2 can be cleaned regularly.

[0036] In the aerobic pool 3, microorganisms further reduce ammonia nitrogen, total phosphorus, organic matter, etc. in the grey water, after which the grey water continues to flow to the second anoxic pool 4;

[0037] Since the coarse particles or residues in the black water are relatively smaller and lighter, the black water is directly connected to the third regulating tank 6, and preliminary sedimentation and pollutant reduction are first carried out in the third regulating tank 6, and then the black water flows to the fine grid 9 between the third regulating tank 6 and the first anoxic tank 7, and the particles or residues in the black water are filtered out by the fine grid 9, and flow into the first anoxic tank 7, and nitrate nitrogen, total phosphorus, organic matter, etc. are reduced in the first anoxic tank 7, and then flow into the second anoxic tank 4 through a one-way valve (check valve), and the gray water effluent of the aerobic tank 3 also flows into the second anoxic tank 4, where the treated black water and gray water are mixed, and nitrate nitrogen, total phosphorus, organic matter, etc. are further reduced;

[0038] The mixed water in the second anoxic pool 4 will flow into the downward submerged flow artificial wetland 5, and the downward submerged flow artificial wetland 5 will further reduce the total phosphorus and COD. In addition, the downward submerged flow artificial wetland 5 can also play a certain reduction effect on antibiotics, heavy metals, etc., and has a high ecological value.

[0039] The treatment system can be buried underground, mainly for 5 to 15 users, with a water inlet volume of 2m 3 / d~8m 3 / d, only wetland aquatic plants can be seen, with good visual effects. The length, width and height of the system can be 1.25m~3.5m, 1.2m~3m, and 0.8m~1.0m respectively. Among them, the volumes of the first regulating tank 1, the second regulating tank 2, the aerobic tank 3, the second anoxic tank 4, the third regulating tank 6 and the first anoxic tank 7 can be adjusted according to local water use habits. If the proportion of gray water is relatively large, the capacity of the aerobic tank 3 is appropriately increased, and the proportion of black water is relatively large, then the capacity of the first anoxic tank 7 is appropriately increased. A multi-point water inlet method is adopted, that is, black water and gray water are treated separately. Gray water is mainly kitchen water and washing water, and organic The black water has a low content of substances and an average concentration of nitrogen and phosphorus, while the black water contains a higher concentration of carbon source, and the nitrogen and phosphorus concentration is also high. The carbon source in the black water can be fully utilized to reduce the high concentration of nitrogen and phosphorus, avoiding the problem of insufficient carbon source in rural sewage treatment. When the fertility requirements for farmland irrigation are high, water can be taken from the outlet of the second anoxic pool 4 for irrigation. When the fertility requirements are relatively low, water can be taken from the outlet of the downward submerged flow artificial wetland 5 for irrigation. The effluent can meet the irrigation effluent water quality requirements in the irrigation season, and meet the requirements of township drainage specifications in the non-irrigation season, and can be directly discharged into the receiving water body as ecological water to supplement river and lake water.

[0040] Example 2

[0041] like Figure 2 As shown, this embodiment is a further improvement on the basis of embodiment 1, and the details are as follows:

[0042] The grid spacing of the coarse grid 8 is 8 mm to 12 mm, which can effectively filter heavier and larger particles or residues. The grid spacing of the fine grid 9 is 4 mm to 6 mm, which can effectively filter lighter and finer particles or residues.

[0043] Example 3

[0044] like Figure 1 , Figure 2 As shown, this embodiment is a further improvement on the basis of Embodiment 1 or 2, and the details are as follows:

[0045] The capacity of the second regulating tank 2 is larger than that of the first regulating tank 1 , so the hydraulic retention time is longer, and the pollutants in the gray water to be entered into the aerobic tank 3 can be initially reduced and the water quality and quantity can be adjusted.

[0046] Example 4

[0047] like Figure 1 , Figure 2 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 3, and the details are as follows:

[0048] The guide plate 10 is suspended in the first regulating tank 1, which is conducive to prolonging the water flow retention time, so that heavier particles or residues can be deposited on the bottom of the tank by their own weight;

[0049] The guide plate 10 is suspended in the second regulating tank 2, which is beneficial to prolong the water flow residence time;

[0050] The guide plate 10 is suspended in the third regulating tank 6, which is beneficial to prolong the water flow residence time;

[0051] A baffle 13 is arranged in the first anoxic pool 7 to extend the water flow path so as to effectively reduce nitrate nitrogen, total phosphorus, organic matter, etc.

[0052] Example 5

[0053] like Figure 2 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 4, and the details are as follows:

[0054] An aeration plate 11 is arranged at the bottom of the aerobic pool 3 to aerate and oxygenate the aerobic pool 3 so that its oxygen content is maintained within the target value range. The dissolved oxygen content in the aerobic pool 3 is 4mg / L~5mg / L, and the dissolved oxygen content in the second anoxic pool 4 and the first anoxic pool 7 is 1mg / L~2mg / L.

[0055] Example 6

[0056] like Figure 2 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 5, and the details are as follows:

[0057] Rope-shaped artificial aquatic plants 12 are arranged in the aerobic tank 3, rope-shaped artificial aquatic plants 12 are arranged in the second anoxic tank 4, and rope-shaped artificial aquatic plants 12 are arranged in the first anoxic tank 7. The biofilm method is used to reduce pollutants. Compared with the activated sludge method, it can avoid sludge backflow (eliminating the complex management links in the middle and unnecessary cost expenditures, mainly the purchase of water pumps, water pump maintenance and electricity-related expenses), and the sludge production is less, and the biochemical reduction effect of pollutants is more obvious.

[0058] Furthermore, the arrangement spacing of the rope-shaped artificial water plants 12 is 15 cm to 20 cm.

[0059] Example 7

[0060] like Figure 2 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 6, and the details are as follows:

[0061] The bottom sand layer of the downward subsurface flow artificial wetland 5 is mixed with a slow-release carbon source and anoxic and facultative microbial agents, which can supplement the carbon source and provide microbial agents for the entire wetland system, making the wetland system more effective in nitrogen and phosphorus removal;

[0062] The downward subsurface flow artificial wetland 5 is an unsaturated artificial wetland with an unsaturated ratio of 50%, that is, the lower half of the wetland is flooded, which is conducive to the survival of anoxic anaerobic microorganisms, while the upper half of the wetland is in a water-free state, which is conducive to the survival of aerobic microorganisms. That is, the downward partially unsaturated artificial wetland can first perform aerobic biochemical reactions on the treated mixed water, and then perform anoxic and anaerobic biochemical reactions. Ammonia nitrogen can be effectively treated in the upper half of the wetland, while nitrate nitrogen is mainly reduced in the lower half of the wetland. The wetland can also further reduce total phosphorus and COD, and can also play a certain reduction effect on antibiotics, heavy metals, etc., and has a high ecological value.

[0063] Example 8

[0064] like Figure 1 , Figure 2 As shown, this embodiment is a further improvement on any one of Embodiments 1 to 7, and the details are as follows:

[0065] The first regulating pool 1 and the second regulating pool 2 share a common wall, and the common wall has a hole connecting the first regulating pool 1 and the second regulating pool 2. The coarse grid 8 between the first regulating pool 1 and the second regulating pool 2 is arranged in the hole on the common wall, which effectively saves costs;

[0066] The second regulating pool 2 and the aerobic pool 3 share a wall, and the shared wall has a hole connecting the second regulating pool 2 and the aerobic pool 3. The fine grid 9 between the second regulating pool 2 and the aerobic pool 3 is arranged in the hole on the shared wall, which effectively saves costs;

[0067] The third regulating pool 6 and the first anoxic pool 7 share a wall, and the shared wall has a hole connecting the third regulating pool 6 and the first anoxic pool 7. The fine grid 9 between the third regulating pool 6 and the first anoxic pool 7 is arranged in the hole on the shared wall, which effectively saves costs.

[0068] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and cannot be understood as limitations of the present invention. Ordinary technicians in the field can change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. A decentralized rural domestic sewage treatment system, characterized in that: include: A first regulating pool (1), a second regulating pool (2), an aerobic pool (3), a second anoxic pool (4) and a downward submerged artificial wetland (5) are sequentially connected along the direction of grey water flow, and a third regulating pool (6) and a first anoxic pool (7) are connected along the direction of black water flow, water in the first anoxic pool (7) flows into the second anoxic pool (4) through a one-way valve, water in the first regulating pool (1) flows into the second regulating pool (2) through a coarse screen (8), water in the second regulating pool (2) flows into the aerobic pool (3) through a fine screen (9), and water in the third regulating pool (6) flows into the first anoxic pool (7) through a fine screen (9).

2. A decentralized rural domestic sewage treatment system according to claim 1, characterized in that: The grid spacing of the coarse grid (8) is 8 mm to 12 mm, and the grid spacing of the fine grid (9) is 4 mm to 6 mm.

3. A decentralized rural domestic sewage treatment system according to claim 1, characterized in that: The pool capacity of the second regulating pool (2) is larger than the pool capacity of the first regulating pool (1).

4. A decentralized rural domestic sewage treatment system according to claim 1, characterized in that: Guide plates (10) are suspended in the first regulating tank (1), the second regulating tank (2) and the third regulating tank (6), and baffles (13) are arranged in the first anoxic tank (7).

5. A decentralized rural domestic sewage treatment system according to claim 1, characterized in that: An aeration plate (11) is arranged at the bottom of the aerobic pool (3); the dissolved oxygen content in the aerobic pool (3) is 4 mg / L to 5 mg / L; and the dissolved oxygen content in the second anoxic pool (4) and the first anoxic pool (7) is 1 mg / L to 2 mg / L.

6. A decentralized rural domestic sewage treatment system according to claim 1, characterized in that: Rope-shaped artificial aquatic plants (12) are arranged in the aerobic pool (3), the second anoxic pool (4) and the first anoxic pool (7).

7. A decentralized rural domestic sewage treatment system according to claim 6, characterized in that: The arrangement interval of the rope-shaped artificial water plants (12) is 15 cm to 20 cm.

8. A decentralized rural domestic sewage treatment system according to claim 1, characterized in that: The downward subsurface flow artificial wetland (5) is an unsaturated artificial wetland, and the unsaturation ratio is 50%.

9. A decentralized rural domestic sewage treatment system according to claim 1, characterized in that: The first regulating pool (1) and the second regulating pool (2) share a wall, and the shared wall has a hole connecting the first regulating pool (1) and the second regulating pool (2), and a coarse grid (8) between the first regulating pool (1) and the second regulating pool (2) is arranged in the hole on the shared wall; the second regulating pool (2) and the aerobic pool (3) share a wall, and the shared wall has a hole connecting the second regulating pool (2) and the aerobic pool (3), and a fine grid (9) between the second regulating pool (2) and the aerobic pool (3) is arranged in the hole on the shared wall; the third regulating pool (6) and the first anoxic pool (7) share a wall, and the shared wall has a hole connecting the third regulating pool (6) and the first anoxic pool (7), and a fine grid (9) between the third regulating pool (6) and the first anoxic pool (7) is arranged in the hole on the shared wall.

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