CN101781060A - Composite artificial wetland sewage treatment system - Google Patents

Abstract

The invention discloses a composite artificial wetland sewage treatment system, comprising: a pretreatment pool, the pretreatment pool is connected to a vertical flow artificial wetland pool, the lower part of the vertical flow artificial wetland pool is provided with a horizontal underflow artificial wetland pool, and the horizontal underflow artificial wetland pool is located at Under the ground surface, the vertical flow constructed wetland pool is connected to the horizontal subsurface flow constructed wetland pool through the return flow pool; the matrix inside the vertical flow constructed wetland pool is coarse sand layer, artificial mixed layer and gravel layer from top to bottom, and the horizontal subsurface flow constructed wetland pool There are gravel areas on both sides of the pool, and the matrix area in the middle. The matrix area from top to bottom is coarse sand layer, artificial mixed layer, and coarse sand layer. The vertical flow constructed wetland pool contains shallow root plants, and the horizontal subsurface flow constructed wetland pool Plants with deep roots are planted; the upper part of the vertical flow artificial wetland pool is provided with water distribution pipes, and the lower part is provided with discharge channels, and the lower part of the horizontal submerged flow artificial wetland pool is also provided with discharge channels. The invention has high sewage treatment efficiency, good effluent water quality and small occupied area.

Description

Composite Constructed Wetland Sewage Treatment System

technical field

The invention relates to the field of sewage treatment, in particular to a composite artificial wetland sewage treatment method.

Background technique

With the rapid development of my country's social economy and the acceleration of urbanization, on the one hand, the contradiction between urban water supply and demand has become increasingly prominent, and on the other hand, the massive discharge of huge amounts of waste water and sewage has continuously polluted water sources, further deteriorating the water quality environment. At present, among the more than 600 cities in our country, more than 400 cities have different degrees of water shortage problems. The annual water shortage reaches 6 billion tons, and the economic loss caused by water shortage is nearly 300 billion yuan per year. At the same time, the annual sewage discharge in my country's cities has reached 41.4 billion tons. After these huge amounts of sewage enter the surface water bodies, they will cause increasingly serious harm to my country's limited surface water bodies. More than 50% of the rivers in the seven major river basins There are different degrees of pollution problems. A large number of provinces and cities in Jiangsu, Shanghai, Guangzhou and other places are already facing serious water pollution and water shortage problems. The embarrassing situation of too much water is difficult to use”. Whether it is the original resource-based water shortage or the water pollution-based water shortage, it has seriously affected and restricted the sustainable development of my country's social economy. How to solve this problem has become a very important research topic in my country's social and economic development. In the outline of the "Tenth Five-Year Plan", the strategic conception of sewage resource utilization is undoubtedly one of the effective means. It can greatly reduce the amount of sewage discharge, improve the ecological environment of surface water bodies, reduce the investment and operation costs of drainage projects, and can also greatly increase the amount of water available, reduce water supply treatment and water supply costs, reduce economic losses caused by water shortages, and improve people's livelihood. Survive a healthy environment and promote the development of industry, tourism and aquaculture. However, the implementation of my country's sewage resource utilization strategy has been struggling. At present, my country's sewage purification and reuse rate is still very low. Although there are many reasons for this situation, the main reason is the sewage purification and reuse technology, which cannot meet the requirements of the marketization of sewage resources. Although the traditional biological aeration tank technology in the past can effectively remove organic matter in sewage, its ability to remove nitrogen and phosphorus is low, and the quality of effluent water cannot meet the standard for reclaimed water reuse; although the effluent water quality of membrane bioreactor technology is relatively high , but the high investment and operation costs limit the wide application of this technology. Other chemical and physical treatment technologies also have problems such as high investment and operation costs, unstable effluent quality, and secondary pollution.

The constructed wetland sewage treatment technology currently in operation has the characteristics of high efficiency, low investment, low operating cost, and low maintenance technology, and has received more and more attention worldwide. But at the same time, there are also: can not directly treat sewage, poor adaptability, can only carry out advanced treatment for sewage after primary or secondary treatment; low absorption efficiency for heavy metal pollutants; technology is greatly affected by ambient temperature; easy to breed mosquitoes in summer and other shortcomings . The existing constructed wetland sewage treatment technologies can basically be divided into surface flow, vertical flow and subsurface flow. Surface flow constructed wetlands are the most primitive constructed wetlands, similar to natural wetlands, with shallow water depth, generally around 0.2-0.4 meters, and wastewater flows through the wetland surface. This type of constructed wetland occupies a large area, has a small hydraulic load rate, limited decontamination capacity, limited oxygen transmission capacity, is greatly affected by climate, and is prone to breed mosquitoes and flies in summer. Vertical flow wet artificial land has insufficient ability to remove organic matter, and there is also a phenomenon of breeding mosquitoes and flies in summer. Subsurface flow constructed wetlands have insufficient oxygen supply and poor nitrification. In recent years, people have proposed composite constructed wetland sewage treatment methods, which can combine the advantages of various types of constructed wetlands, but there are also disadvantages such as large area, unsatisfactory sewage treatment effect, and inability to make good use of the adsorption and filtration of wetland substrates. Therefore, in order to make great progress in the implementation of my country's sewage resource utilization strategy, it is of great significance to develop and research new ecological sewage purification and reuse technologies.

Contents of the invention

The technical problem to be solved by the present invention is to provide a composite constructed wetland sewage treatment system with high sewage treatment efficiency, high sewage purification efficiency per unit area, and good effluent quality.

In order to solve the above technical problems, the technical solution adopted by the present invention is: a composite constructed wetland sewage treatment system, including: a pretreatment pool, the pretreatment pool is connected to the vertical flow constructed wetland pool, and the lower part of the vertical flow constructed wetland pool is provided with a horizontal undercurrent The constructed wetland pool, the horizontal subsurface flow constructed wetland pool is located under the ground surface, and the vertical flow constructed wetland pool is connected to the horizontal subsurface flow constructed wetland pool via the return flow pool; the matrix inside the vertical flow constructed wetland pool is coarse sand layer, Artificial mixed layer and gravel layer, gravel areas are arranged on both sides of the horizontal subsurface flow constructed wetland pool, the middle is a matrix area, and the matrix area of the horizontal subsurface flow constructed wetland pool is coarse sand layer, artificial mixed layer, coarse sand layer from top to bottom. The vertical flow constructed wetland pool is planted with shallow root plants, and the horizontal subsurface flow constructed wetland pool is planted with deep root plants; the upper part of the vertical flow constructed wetland pool is equipped with water distribution pipes, and the lower part is equipped with discharge grooves, and the lower part of the horizontal subsurface flow constructed wetland pool is also Has a drain tank.

A further improvement is also provided with a sump for secondary treatment of sewage. There is a sewage pump in the sump. The sewage pump is connected to the water distribution pipe on the upper part of the vertical flow artificial wetland pool, and the drainage tank of the horizontal submerged flow artificial wetland pool is connected through pipelines. Sump.

A further improvement is also provided with a tail water purifying agent feeding system for ecologically restorative treatment of the treated sewage, and the tail water purifying agent feeding system is connected to the sump through pipelines.

A further improvement is also provided with a thermal insulation power system. The thermal insulation power system includes a solar greenhouse and a solar panel positioned on the outer wall of the solar greenhouse. The main structure of the solar greenhouse is a steel structure, and the outer wall of the solar greenhouse is a closed space composed of light-transmitting glass.

Preferably, a sewage pump is provided in the above-mentioned backflow pool, and the sewage pump is connected to the water inlet and out of the gravel area of the horizontal submerged flow artificial wetland pool through pipelines, and the backflow pool is connected to the discharge tank of the vertical flow artificial wetland pool through pipelines, and the backflow pool is provided with submersible exposure. The submersible aerator is connected to the microporous aeration pipe arranged at the bottom of the horizontal submerged flow constructed wetland pool.

Preferably, the above-mentioned pretreatment tank is provided with a water inlet and a water outlet, and a grid for preliminary filtering of impurities in the sewage is provided in the pretreatment tank. One side of the grid is composed of grid bars and transverse ribs, and the other side is provided with sieve.

Preferably, the artificial composite layers of the vertical flow constructed wetland pool and the horizontal subsurface flow constructed wetland pool are all made of vermiculite, zeolite, and coal cinder, and the height is at least 20 cm.

Preferably, the above-mentioned vertical flow constructed wetland pool and the bottom of the discharge tank of the horizontal subsurface constructed wetland pool are provided with a waterproof layer, and the waterproof layer at the bottom of the discharge tank of the vertical flow constructed wetland pool is provided with a plant stem that can accommodate deep root system enrichment. The inside of the prefabricated hole is filled with flexible plastic waterproof filler, the upper part of the discharge tank of the vertical flow constructed wetland pool is provided with a permeable plate, and the horizontal submerged flow artificial wetland pool is equipped with a diversion baffle, which forms an S shape of water flow channels.

The beneficial effects produced by adopting the above technical solution are: 1. The present invention integrates the advantages of various artificial wetland treatment methods, not only can efficiently remove inorganic eutrophication elements in sewage, but also can effectively remove organic matter and heavy metal pollution in sewage The effective decomposition and adsorption of substances can greatly improve the purification efficiency of sewage per unit area, so that the quality of the purified effluent can reach the standard of advanced treatment, and because of the use of vertical composite structures, the floor area can be saved.

2. The present invention comprehensively utilizes various forms of constructed wetlands to purify sewage in multiple directions in multiple directions. The purification time is sufficient, and the interception, filtration, adsorption and other functions of the substrate are better utilized. At the same time, it is also easy to overcome the problem of vertical flow that is easy to block. question.

3. The problem of small amount of oxygen compensation in the horizontal subsurface layer can be solved by setting the aeration device.

4. Further improving the installed solar energy system can make the invention not affected by the seasonal temperature, not only can it run when the temperature is high in spring and summer, but also can run normally when the temperature is low in autumn and winter, which solves the problem of the processing efficiency of artificial wetland in winter in the north. The problem of reducing; and the use of solar heat collection and power supply to treat sewage can greatly reduce costs and improve sewage treatment efficiency.

5. Further improvement Through the setup of tail water purification agent feeding system, the treated and non-recycled reclaimed water can be treated with ecological restoration, and discharged into the natural water system without causing ecological burden.

6. Compared with the traditional artificial wetland treatment technology, the present invention can save more than 50% of the floor area, increase the treatment efficiency per unit area by more than 60%, and stabilize the effluent quality; the present invention completely uses natural technology to purify sewage , no secondary pollution.

Description of drawings

Fig. 1 is a structural representation of the present invention;

Figure 2 is a schematic diagram of a horizontal subsurface flow wetland pool;

Fig. 3 is the top view of Fig. 2;

Figure 4 is a schematic diagram of a vertical flow wetland pool;

Fig. 5 is the schematic diagram of water distribution pipe;

Fig. 6 is the schematic diagram of microporous aeration tube;

Figure 7 is a schematic diagram of a vertical flow wetland pool;

Figure 8 is a schematic diagram of the grid;

Figure 9 is a top view of Figure 8;

Among them, 1. Floor surface; 2. Pretreatment pool; 3. Grille; 4. Solar panels; 5. Shallow root plants; 6. Water distribution pipes; Artificial mixed layer of vertical flow artificial wetland pool; 9. Gravel layer; 10. Discharge tank of vertical flow wetland pool; 11. Tail water water purification agent feeding tank; 12. Collecting tank; 13. Sewage pump in the collecting tank; 14. Sewage pump in the backflow pool; 15. Sewage pump; 16. Submersible aerator; 17. Backflow pool; 19. Coarse sand layer in the horizontal underflow artificial wetland pool; 20. Discharge tank; 21. Horizontal underflow artificial wetland pool 22. Coarse sand layer; 23. Diversion baffle; 24. Sewage pump; 25. Greenhouse light-transmitting outer wall; 26. Grille; 27. Transverse rib; 28. Screen; Wetland pool; 30. Horizontal underflow artificial wetland pool; 31. Water distribution main pipe; 32. Water distribution branch pipe; 33. Gravel area at water inlet; 34. Gravel area at water outlet; 35. Microporous aeration pipe; 36. Drainage tank Waterproof layer at the bottom; 37. Waterproof layer at the top of the discharge tank; 38. Waterproof layer of the vertical flow artificial wetland pool; 39. Permeable plate of the vertical flow artificial wetland pool; 40. Pre-set holes; 41. Flexible plastic waterproof filler .

Detailed ways

The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Referring to accompanying drawing 1, the sewage to be treated first flows into the pretreatment tank 2, and the pretreatment tank 2 is equipped with a grid 3 to filter large floating and suspended solids, reduce scum produced by subsequent treatment, and ensure the normal operation of the sewage treatment equipment. It can also be pretreated by adding water purifier or gravity sedimentation method. The pretreated sewage flows into the vertical flow artificial wetland pool 29 through the sewage pump 24 through the water distribution pipe 6, and the flow rate is controlled by the valve. The water distribution pipe 6 is arranged on the surface of the vertical flow artificial wetland pool, and is composed of a water distribution main pipe 31 and a water distribution branch pipe 32, which is in the shape of a "king" and can distribute water evenly. The matrix of the vertical flow constructed wetland pool 29 is composed of a coarse sand layer 7, an artificial mixed layer 8 and a gravel layer 9 from top to bottom. The artificial mixed layer 8 is made of zeolite, vermiculite, and cinder. , in accordance with the principles of dense top and loose bottom, fine particles on the top, and coarse particles on the bottom. Among them, the preferred particle size is 0.2-1.5 cm for vermiculite, 1.4-2.5 cm for zeolite, 3-7 cm for cinder, 2-7 mm for coarse sand layer, and 4-8 cm for bottom gravel. Sewage vertically infiltrates and adsorbs some heavy metal pollutants through layers of matrix. The nitrification ability of plant roots and microbial flora growing in the matrix focuses on the removal of nitrogen and ammonia inorganic substances. It decreased sharply, but the organic pollutants and heavy metal pollutants in the sewage did not decrease significantly.

After the sewage passes through the vertical flow artificial wetland pool 29, it flows into the backflow pool 17 through the drain tank 10 at the bottom of the pool. The backflow pool 17 is the collection place for the sewage treated by the vertical flow artificial wetland pool 29, and then the sewage pump 14 flows the sewage into the horizontal subsurface flow The constructed wetland pool 30 uses a valve to control the inflow rate. The horizontal underflow artificial wetland pool is provided under the floor surface, which is conducive to winter heat preservation and improves the work efficiency in winter in the north. The horizontal submerged flow pool is mainly equipped with a variety of enrichment plants, such as reed, myrtle, calamus, water onion, etc., and the super-enrichment plants are comprehensively configured. Through the strong absorption function of various enrichment plants for heavy metal pollutants, the sewage The purpose of removing heavy metal pollutants, at the same time, in the horizontal subsurface flow constructed wetland pool, a plant-microbiota ecosystem will be formed, and a large number of dominant microbial groups will appear in the substrate and root system, relying on the microbial flora to further decompose organic pollutants and heavy metal pollutants. Substrate and microporous aeration pipe 35 are arranged in the horizontal subsurface flow constructed wetland pool 30 , and the submersible aerator 16 supplies oxygen to the horizontal subsurface flow constructed wetland pool through the microporous aeration pipe 33 for micro-aeration. Ordinary horizontal subsurface flow wetlands mainly rely on plant transportation to realize vertical oxygen compensation, and the compensation amount is small. However, the vertical flow wetland pool itself in the present invention can increase the vertical oxygen infiltration, and then use the backflow pool 17 and the micro-aeration device to be more effective. Increase the oxygen content of the system, improve the reaction purification efficiency of plant roots and microbial flora, efficiently treat and absorb heavy metal pollutants, and decompose organic pollutants. After the sewage passes through the horizontal underflow artificial wetland pool 30, the organic pollutants and heavy metal pollutants will be greatly reduced, and the inorganic pollutants will be further reduced. The treated water will flow into the sump 12, which can monitor the sewage treatment effect and Sewage pump 13 and pipelines are provided to allow sewage to flow back for secondary treatment. The treated reclaimed water can be recycled, and the reclaimed water in the sump can be discharged after ecological restoration treatment by using the tail water purifying agent feeding system. The feeding system of tail water purifying agent adopts the ecological and environmental protection compound water treatment agent made of diatomite, sepiolite, lotus leaf, reed, zeolite and other pure natural materials, which can precipitate pollutants and restore the natural components of water body The characteristics of this method are to carry out ecological restoration treatment on the treated and non-recycled reclaimed water, and discharge it into the natural water system without causing ecological burden. Please refer to the patent of Publication No. CN101003401A "An Ecologically Environmentally Friendly Composite Water Treatment Agent".

Referring to accompanying drawing 1, the whole system of the present invention is in the solar greenhouse 25, and the solar panel 4 is hung on the outside of the solar greenhouse 25. When the ambient temperature is low, the solar greenhouse 25 can capture solar heat and increase the indoor temperature to ensure the normal growth of aquatic plants throughout the year and provide a good living and breeding environment for microbial flora; on the other hand, it can also convert solar energy to provide The submersible aerator 16 provides working power and saves energy. This can solve the problem of low efficiency of the constructed wetland sewage treatment technology in cold winter conditions in the north.

Referring to accompanying drawings 2 and 3, both sides of the horizontal subsurface flow constructed wetland pool 30 are gravel areas, one side is the gravel area 33 at the water inlet, and the other side is the gravel area 34 at the water outlet, and the diameter of the gravel at the water inlet is 8-15mm The diameter of the gravel at the water outlet is 2-4 cm. The gravel area 34 at the water outlet does not fill the area surrounded by the water-conducting partition 23, but adds some gravel. Adding some gravel at the water outlet can effectively prevent clogging and facilitate Water is better discharged, and the lower part of the gravel area 34 at the water outlet is provided with a water-permeable plate, and the remaining position of the gravel area 34 at the water outlet is provided with a waterproof layer 37 at the top of the discharge groove. The matrix consists of a coarse sand layer 22, an artificial mixed layer 21, and a coarse sand layer 19 from top to bottom. The artificial mixed layer 21 is made of zeolite, vermiculite, and coal cinder. Loose, the principle of fine particles on the top and coarse particles on the bottom. Among them, the preferred particle size is 0.2-1.5 cm for vermiculite, 1.4-2.5 cm for zeolite, 3-7 cm for cinder, and 2-7 mm for coarse sand layer. The set guide partition 23 makes the water flow form an S-like channel, which can increase the sewage treatment effect.

Referring to accompanying drawing 4, shallow-rooted plants 5 are planted in the vertical flow wetland pool 29, and the plants have an enrichment effect. Because the vertical flow wetland pool is above the surface, the selected plants are mainly shallow-rooted or floating water plants, and inorganic pollutants It has strong processing ability and has landscape effects at the same time, such as rushes, water lilies, quinces, mosaic canna, etc. The sewage evenly flows into the vertical flow constructed wetland pool 29 through the water distribution pipe 6, and finally flows into the drain through the permeable plate 39 on the upper wall of the drain tank 10 of the vertical flow constructed wetland pool 29, and flows into the return pool 17 through the drain pipe. The waterproof layer 38 and the permeable plate 39 of the vertical flow constructed wetland pool are both square honeycomb structures, and holes are reserved above to allow the stems of deep-rooted plants in the horizontal subsurface flow wetland pool to pass through. In order to prevent the water being treated from flowing directly into the horizontal underflow wetland pool, and to ensure the normal growth of plants, the waterproof layer 38 will lay flexible plastic waterproof fillers such as plastic between the holes and plant stems, not only to prevent sewage from flowing into the pool, but also to It can try to ensure the normal growth of plants without affecting the efficiency. The permeable plate 38 is in direct contact with gravels of large particle size, with less suspended solids and the directly contacted matrix itself is large, not easy to block, and does not require special treatment.

Referring to accompanying drawing 5, the water distribution pipe 6 is a water distribution pipe similar to a "king" shape, and is provided with a water distribution main pipe 31 and a water distribution branch pipe 32. Referring to accompanying drawing 6, the microporous aeration pipe is preferably a porous PVC aeration pipe, and its shape is also similar to the shape of a "king".

Referring to Figure 7, the waterproof layer of the vertical flow constructed wetland pool is made of specially treated rubber or plastic materials. Pre-set holes 40 allow deep rooted plant stalks to pass through.

Referring to accompanying drawing 8, accompanying drawing 9, grid is made up of grid bar 26, transverse rib 27, frame, screen cloth 28, and grid bar can block and filter bulk suspended matter in advance, as branch, food bag etc., then pass grid The following sieves carry out further filtration.

After the sewage treatment system is completed, it will take about 20-27 days to "preheat" the central part of the biological reaction system, so that the plant roots and dominant microbial flora can grow to a stage where they can stably process and digest sewage.

In the principle test of the present invention, experiment was carried out respectively for river course domestic sewage in Baoding City, certain paper mill sewage and certain electroplating plant industrial wastewater, and the experimental data obtained are as follows: COD is the chemical oxygen demand in the following examples, and BOD is Biochemical oxygen demand, SS for suspended solids, TP for total phosphorus.

Table 1

River domestic sewage (unit: mg/L)

COD BOD SS Ammonia TP Sulfide water inlet 157 125 73.7 27.8 3.9 2.7 After tail water feeding 19 7.8 3.3 6.1 0.21 0.18 Purification ratio 87.90% 93.76% 98.93% 78.06% 94.62% 93.33%

Table 2

Sewage from paper mills (unit: mg/L)

COD SS Sulfide Chroma Volatile phenol water inlet 4800 1077 15.1 96 1.7

COD SS Sulfide Chroma Volatile phenol After tail water feeding 58 27.7 0.4 12 0.16 Purification ratio 98.79% 97.43% 97.35% 87.5% 90.59%

In the sewage treatment experiment of the paper mill, because the level of pollutants contained in the sewage was too high, the residual amount was very high in the first collection tank sampling inspection. After the backflow retreatment function was turned on, the treatment was repeated twice, so that the tail water reached The national sewage secondary discharge standard. The unit mg/L in Table 2 does not include the unit of chromaticity.

table 3

Industrial wastewater from electroplating plants (unit: mg/L)

COD Cr Zn Fe Mn SS pH water inlet 151 23.78 14.86 43.16 24.22 145 3.53 After tail water feeding 2 0.9 0.6 0.7 0.5 8 6.9 Purification ratio 98.68% 96.21% 95.95% 98.37% 97.94% 94.48% -

In the sewage treatment experiment of the electroplating plant, the level of heavy metal pollutants contained in the sewage was relatively high. In the first sampling inspection of the sump, although the treatment rate of each heavy metal pollutant reached about 70%, the content has not yet reached the national sewage level. Secondary discharge standard, after turning on the backflow retreatment function, repeat the treatment twice, so that the tail water meets the national sewage secondary discharge standard. The unit mg/L in Table 3 does not include the unit of pH.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the present invention will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims (8)

1. A composite constructed wetland sewage treatment system, characterized in that: comprising: a pretreatment pond (1), the pretreatment pond (1) is connected to a vertical flow constructed wetland pond (29), and the bottom of the vertical flow constructed wetland pond (29) is arranged There is a horizontal subsurface flow constructed wetland pool (30), the horizontal subsurface flow constructed wetland pool (30) is arranged under the ground surface, and the vertical flow constructed wetland pool (29) is connected to the horizontal subsurface flow constructed wetland pool (30) via the return flow pool (17); The matrix inside the vertical flow constructed wetland pool (29) is a coarse sand layer (7), an artificial mixed layer (8) and a gravel layer (9) from top to bottom, and the horizontal subsurface flow constructed wetland pool (30) is equipped with There is a gravel area and the matrix area in the middle. The matrix area from top to bottom is coarse sand layer (22), artificial mixed layer (21), and coarse sand layer (19). The vertical flow constructed wetland pool (29) contains shallow Root plants, the horizontal submerged flow constructed wetland pool (30) is planted with deep rooted plants; the upper part of the vertical flow constructed wetland pool (29) is provided with a water distribution pipe (6), and the lower part is provided with a discharge groove (10), and the lower part of the horizontal subsurface flow constructed wetland pool A discharge groove (20) is provided. 2. The composite constructed wetland sewage treatment system according to claim 1, characterized in that: it is also provided with a sump (12) for secondary treatment of sewage, and a sewage pump (13) is arranged in the sump (12), and the sewage The pump (13) communicates with the water distribution pipe (3) located on the top of the vertical flow constructed wetland pool (29), and the drain tank (20) of the horizontal submerged flow constructed wetland pool (30) communicates with the sump (12) through pipelines. 3. The composite thermal wetland sewage treatment system according to claim 2, characterized in that: it is also provided with a tail water purifying agent feeding system (11) for carrying out ecological restoration treatment of the treated sewage, and the tail water purification The water agent feeding system is connected to the sump (12) through pipelines. 4. The composite constructed wetland sewage treatment system according to claim 1, 2 or 3, characterized in that: it is also provided with a thermal insulation power system, and the thermal insulation power system includes a solar greenhouse (25) and a solar panel positioned on the outer wall of the solar greenhouse (4), the main structure of the solar greenhouse (25) is a steel structure, and the outer wall of the solar greenhouse is formed of a closed space by light-transmitting glass. 5. The composite constructed wetland sewage treatment system according to claim 1, characterized in that: a sewage pump (14) is provided in the return flow pool (17), and the sewage pump (14) is connected to the horizontal submerged flow constructed wetland pool through pipelines The gravel area (33) at the water inlet of (30), the backflow pool (17) is connected to the discharge tank (10) of the vertical flow constructed wetland pool (29) by pipelines, and the backflow pool (17) is provided with a submersible aerator (16 ), the submersible aerator (16) communicates with the microporous aeration pipe (35) located at the bottom of the horizontal subsurface flow constructed wetland pool (30). 6. The composite constructed wetland sewage treatment system according to claim 1, characterized in that: the pretreatment pool (1) is provided with a water inlet and a water outlet, and the pretreatment pool (1) is provided with impurities for sewage The grille (2) for preliminary filtering, one side of the grille (2) is composed of grid bars (26) and transverse ribs (27), and the other side is provided with a screen (28). 7. The composite constructed wetland sewage treatment system according to claim 1, characterized in that: the artificial composite layer (8, 21) is made of vermiculite, zeolite and cinder, and its height is at least 20cm. 8. The composite constructed wetland sewage treatment system according to claim 1, characterized in that: the bottoms of the discharge tanks of the vertical flow constructed wetland pool (29) and the horizontal subsurface flow constructed wetland pool (30) are provided with a waterproof layer, The waterproof layer (38) at the bottom of the discharge tank of the vertical flow artificial wetland pool is provided with prefabricated holes (40) that can allow the stems of deep root plants to pass through, and the inside of the prefabricated holes (40) is filled with flexible plastic waterproof fillers (41) , the upper part of the discharge groove (10) is provided with a water-permeable plate (39); the horizontal submerged flow artificial wetland pool (30) is provided with a diversion partition (23), and the diversion partition (23) forms an S-shaped water flow channel.

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