CN113149336A

CN113149336A - Multistage advanced sewage treatment system

Info

Publication number: CN113149336A
Application number: CN202110296415.8A
Authority: CN
Inventors: 何睦盈; 吴美香; 张密德; 舒俭; 冯梓铭
Original assignee: Guangzhou Meiya Energy Saving And Environmental Protection Co ltd
Current assignee: Guangzhou Meiya Energy Saving And Environmental Protection Co ltd
Priority date: 2021-03-19
Filing date: 2021-03-19
Publication date: 2021-07-23

Abstract

The invention relates to the technical field of sewage treatment, and more particularly, to a multi-stage sewage deepening treatment system. The system improves the purification process of sewage in-depth treatment, improves the structure of the traditional anoxic tank and aerobic tank, effectively removes organic pollutants, nitrogen and phosphorus and other substances, improves the purification effect without generating a large amount of sludge, and avoids secondary pollution. , the sewage treatment effect is obvious. At the same time, it also combines the magnetic coagulation sedimentation separation technology. The magnetic powder and flocculant used have a good adsorption effect on bacteria, viruses, oil and various tiny particles, and the removal effect is better than the traditional process. The system specifically includes a collection tank, anoxic ecological filter tank, aerobic ecological filter tank, a return tank, a magnetic separation tank and a clear water tank that are connected in sequence, and the raw water is effectively filtered step by step. The invention improves the traditional treatment process, more scientifically arranges water purification processes at all levels, has obvious sewage treatment effect, and effectively removes organic pollutants, nitrogen and phosphorus and other substances.

Description

Multistage advanced sewage treatment system

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a multistage sewage advanced treatment system.

Background

The advanced treatment of sewage refers to a further water treatment process for reusing the sewage as a water resource for production or life after primary and secondary treatment of urban sewage or industrial wastewater in order to reach a certain reuse water standard. Aiming at the raw water quality of the sewage (wastewater) and the water quality requirement after treatment, a three-stage treatment or multi-stage treatment process can be further adopted. In the traditional treatment process, the anoxic tank and the aerobic tank adopt a contact oxidation method, only biological fillers and water are arranged in the tanks, and the water accounts for the most part, so that a large amount of sludge is generated in the purification treatment process, and secondary pollution is easily caused.

Chinese patent publication No. CN203238141U, 10/16/2013, discloses a membrane filtration system for biological sewage treatment, which comprises a grid well, an adjusting tank, an anoxic tank, an aerobic tank, a membrane filtration tank and a clean water tank, which are sequentially connected, and sewage is purified in stages by sequentially passing through the tanks. Wherein the oxygen deficiency pond and the aerobic pond adopt the traditional treatment process, and biological fillers and water are arranged to culture microorganisms for purifying water, the traditional process is easy to generate a large amount of sludge, and although the bottom of the pond is subjected to sludge backflow through a backflow pump, secondary pollution to water is difficultly avoided.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a multistage advanced sewage treatment system, improves the traditional treatment process, arranges all stages of water purification processes more scientifically, has obvious sewage treatment effect, and effectively removes organic pollutants, nitrogen, phosphorus and other substances.

In order to solve the technical problems, the invention adopts the technical scheme that:

a multistage sewage advanced treatment system comprises a water collecting tank, an anoxic ecological filter tank, an aerobic ecological filter tank, a backflow tank, a magnetic separation tank and a clean water tank which are sequentially communicated. The anoxic ecological filter tank comprises a vegetable layer, a fine sand layer, a coarse sand layer, a rattan cotton layer, a first carbon powder layer, a biological filler layer, a second carbon powder layer, a coarse stone layer and a filter cloth layer which are sequentially laid from top to bottom, wherein the vegetable layer is provided with a water distribution pipe for water inlet, a water outlet pipe is arranged below the filter cloth layer, and water holes are uniformly formed in the water distribution pipe and the water outlet pipe; the aerobic ecological filter tank is similar to the anoxic ecological filter tank in structure, and the aerobic ecological filter tank further comprises an air distribution system.

The sewage is collected into a water collecting tank, sequentially passes through an anoxic ecological filter tank, an aerobic ecological filter tank, a reflux tank and a magnetic separation tank, is finally stored in a clean water tank, is filtered and purified from top to bottom in the anoxic ecological filter tank and the aerobic ecological filter tank, for example, the sewage enters the anoxic ecological filter tank through a water distribution pipe, sequentially passes through a vegetable layer, a fine sand layer, a coarse sand layer, a rattan cotton layer, a first carbon powder layer, a biological filler layer, a second carbon powder layer, a coarse stone layer and a filter cloth layer, and is finally discharged from a bottom water outlet pipe. The difference of the aerobic tank is that the gas distribution system continuously aerates to culture aerobic microorganisms during purification.

Further, the vegetable layer is a water purification plant, and the rattan cotton layer is used for culturing nitrifying bacteria; the first carbon powder layer and the second carbon powder layer are mixed with fine sand. The water purifying plants are generally plants such as grassiness and canna, and the existence of the water purifying plants can prevent blockage. The rattan cotton layer is made of biochemical cotton, is mainly used for culturing nitrobacteria, and the nitrobacteria decompose toxic NH3/NH4 and NO2 in sewage and convert the toxic NH3/NH4 and the NO2 into nontoxic NO3, so that the water quality can be improved, the survival rate of fishes can be improved, and the rattan cotton layer is a filtering material with physical and biochemical filtering effects, has good elasticity and large surface area, is not easy to damage, and can effectively filter impurities in water.

Further, the biological filler layer comprises biological film-forming filler and particles which are formed by mixing, wherein the particles are plastic particles or ceramic particles; the particles are spherical structures, and water storage materials are embedded in the particles. The biological filler is mainly used as a microbial carrier, and organic pollutants, nitrogen, phosphorus and the like are removed under the action of microbes adsorbed on the biological filler. Wherein the water storage material, such as sponge, stores water for the microorganisms.

Further, the air distribution system comprises a first air blower and an air inlet pipe, the air inlet pipe is horizontally arranged below the filter cloth layer, and air holes are uniformly formed in the air inlet pipe; the inlet air is externally communicated with a first air blower. The first air blower blows air to the air inlet pipe, the air enters the aerobic ecological filter tank through air holes in the air inlet pipe, and the air is dispersed into tiny bubbles, so that dissolved oxygen in water is increased. Usually, a vertical air pipe can also be adopted to penetrate through each layer until the horizontal air inlet pipe at the bottom is communicated, and air distribution is carried out, wherein the flowing direction is from top to bottom. The biological filler layer is used as a carrier for the growth of microorganisms, so that the microorganisms further decompose organic matters in the water in an aerobic environment, thereby further reducing the concentration of Chemical Oxygen Demand (COD).

Further, the catch basin is including the first pond and the second pond that set up side by side, first pond and second pond bottom intercommunication, first pond is equipped with the grid, and the second pond is equipped with and is used for pumping drainage to the elevator pump in oxygen deficiency ecological filter pond. The grating is used for filtering large pieces of garbage and is not described in detail since the grating is a common prior art. And the sewage filtered by the grating enters the second water tank from the bottom of the first water tank.

Furthermore, the backflow tank is provided with a backflow pump for pumping and refluxing water to the anoxic ecological filter tank. The reflux pool is used as a transit pool, one of which is used for pumping and refluxing water and carrying out secondary or tertiary filtration of the anoxic ecological filter pool and the aerobic ecological filter pool.

Further, the magnetic separation pond includes that one-level that once communicates mixes pond, second grade and mixes pond, tertiary pond and sedimentation tank, one-level mixes pond, second grade and mixes pond, tertiary pond and all independently is equipped with the dosing pump, the sedimentation tank is equipped with the mud scraper. The sewage sequentially passes through the three mixing tanks, is mixed with various medicaments to form larger floc particles, and finally enters a settling tank for rapid sedimentation, and is promoted by a mud scraper to complete separation, and the effluent enters a clean water tank.

Furthermore, the primary mixing tank, the secondary mixing tank and the tertiary mixing tank are all provided with stirring paddles, and each dosing pump is respectively provided with a coagulant, magnetic powder and a flocculant. The sewage to be treated firstly enters a primary mixing tank of a treatment device, a coagulant PAC is added into the primary mixing tank, the primary mixing tank and the coagulant PAC are fully mixed and then enter a secondary mixing tank, the secondary mixing tank and the magnetic powder are mixed and flocculated, and then the sewage enters a tertiary mixing tank and reacts with a flocculating agent PAM added into the tertiary mixing tank to generate larger floc particles. The stirring paddle is used for accelerating the mixing of the sewage and various medicaments.

Furthermore, the mud scraper is provided with an impeller type rotating rod, the bottom of the sedimentation tank is of an inclined plane structure with a low middle part and high periphery, and the impeller type rotating rod is matched with the inclined plane. The impeller type rotating stick promotes the precipitated floc particles to be separated from the effluent, and the floc particles and the sludge flow to be discharged along the lower part of the sedimentation tank under the action of gravity, thereby completing the separation process of clear water.

Furthermore, the center of the bottom of the sedimentation tank is communicated with a sludge pump for sludge discharge treatment. The center of the bottom of the sedimentation tank is a lower position, after the action of a mud scraper impeller type rotating rod, floc particles and sludge are gathered at the center of the bottom under the action of gravity, and the sludge is pumped out by a sludge pump and discharged or recycled.

Compared with the prior art, the invention has the beneficial effects that: the invention discloses a multistage sewage advanced treatment system, which improves the sewage advanced treatment and purification process, improves the structure of the traditional anoxic tank and aerobic tank, effectively removes organic pollutants, nitrogen, phosphorus and other substances, improves the purification effect, does not generate a large amount of sludge, avoids secondary pollution and has obvious sewage treatment effect. Moreover, by adopting the magnetic coagulation sedimentation separation technology, the adopted magnetic powder and flocculating agent have good adsorption effect on bacteria, viruses, oil and various micro particles, so that the effect of removing the pollutants is better than that of the traditional process, and particularly the effect of removing phosphorus is particularly obvious.

Drawings

Fig. 1 is an overall connection structure diagram of the present invention.

FIG. 2 is a structural view of an aerobic ecological filter according to an embodiment of the present invention.

Fig. 3 is a diagram of a sump structure according to an embodiment of the present invention.

FIG. 4 is a connection structure diagram of the anoxic ecological filter, the aerobic ecological filter and the reflux pool in the embodiment of the invention.

FIG. 5 is a view showing a structure of connection between the magnetic separation tank and the clean water tank according to the embodiment of the present invention.

The system comprises a water collecting tank 1, an anoxic ecological filter tank 2, an aerobic ecological filter tank 3, a reflux tank 4, a magnetic separation tank 5, a clean water tank 6, a vegetable layer 7, a fine sand layer 8, a coarse sand layer 9, a rattan cotton layer 10, a first carbon powder layer 11, a biological packing layer 12, a second carbon powder layer 13, a coarse stone layer 14, a filter cloth layer 15, a water distribution pipe 16, a water outlet pipe 17, a first air blower 18, an air inlet pipe 19, a first water tank 20, a second water tank 21, a grid 22, a lift pump 23, a reflux pump 24, a first-stage mixing tank 25, a second-stage mixing tank 26, a third-stage mixing tank 27, a sedimentation tank 28, a dosing pump 29, a mud scraper 30, a stirring paddle 31, a impeller-type rotating rod 32 and a mud discharging pump 33.

Detailed Description

The drawings are for illustrative purposes only and are not to be construed as limiting the patent; for the purpose of better illustrating the embodiments, certain features of the drawings may be omitted, enlarged or reduced, and do not represent the size of an actual product; it will be understood by those skilled in the art that certain well-known structures in the drawings and descriptions thereof may be omitted. The positional relationships depicted in the drawings are for illustrative purposes only and are not to be construed as limiting the present patent.

The same or similar reference numerals in the drawings of the embodiments of the present invention correspond to the same or similar components; in the description of the present invention, it should be understood that if there are terms such as "upper", "lower", "left", "right", "long", "short", etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the drawings, it is only for convenience of description and simplicity of description, but does not indicate or imply that the device or element referred to must have a specific orientation, be constructed in a specific orientation, and be operated, and therefore, the terms describing the positional relationships in the drawings are only used for illustrative purposes and are not to be construed as limitations of the present patent, and specific meanings of the terms may be understood by those skilled in the art according to specific situations.

The technical scheme of the invention is further described in detail by the following specific embodiments in combination with the attached drawings:

examples

In the prior art, the reason why the simultaneous denitrification and dephosphorization functions are generally completed by only adopting a single biological treatment unit is that: the principle of biological phosphorus removal is that phosphorus is released by phosphorus-accumulating microorganisms in an anaerobic environment, and excessive phosphorus accumulation is carried out in an aerobic environment. Therefore, if the biological system has the phosphorus removal function, an anaerobic tank is required to be added. Anaerobic and anoxic differ in that: both environments require less dissolved oxygen, but the anaerobism is more severe, and there cannot be any other electron acceptor than oxygen, such as nitrate. And the anaerobic environment needs to be controlled more strictly because the nitrate is available to complete the conversion of the nitrate into nitrogen, namely denitrification. In addition, because the phosphorus-accumulating bacteria need to go through two environments, namely anaerobic environment and aerobic environment, in order to complete phosphorus removal, the microorganisms must be in the form of the flowing activated sludge, namely the suspended growth microorganisms, so that the filler cannot be added in the reactor, the microorganism added in the filler can be attached to the filler, the filler can provide an attachment carrier for the microorganisms to improve the biomass, but the microorganisms are fixed and can not flow, and therefore the phosphorus-accumulating bacteria cannot be switched between the anaerobic environment and the aerobic environment. Thus, the reactor cannot be filled with the catalyst. On one hand, biomass can not be improved through the filler without adding the filler, on the other hand, the biomass can not be improved through the filler without fixing the filler, and microorganisms grow in a suspended manner, flow out of the reactor along with water and finally precipitate in a sedimentation tank, so that sludge backflow is also required to be added, namely, the sludge is refluxed into the reactor, so that the process flow is quite complicated, and the phosphorus removal effect is low

In order to solve the problem, the embodiment provides a multistage sewage advanced treatment system, improves sewage advanced treatment and purification technology, improves traditional oxygen deficiency pond, good oxygen pond structure, effectively gets rid of matters such as organic pollutant and nitrogen phosphorus, improves purifying effect and does not produce a large amount of mud, has avoided secondary pollution, and sewage treatment effect is obvious.

As shown in figure 1, the system comprises a water collecting tank 1, an anoxic ecological filter tank 2, an aerobic ecological filter tank 3, a return tank 4, a magnetic separation tank 5 and a clean water tank 6 which are communicated in sequence.

Wherein, sewage is concentrated into catch basin 1 earlier, catch basin 1 has included first pond 20 and the second pond 21 that sets up side by side, first pond 20 and the intercommunication of second pond 21 bottom, first pond 20 is equipped with and is used for filtering major possession rubbish grid 22, second pond 21 is equipped with and is used for the elevator pump 23 of pumping drainage to oxygen deficiency ecological filter 2, the sewage that filters through grid 22 enters into second pond 21 from first pond 20 bottom, then receives the effect of elevator pump 23, pours into oxygen deficiency ecological filter 2 into, as shown in fig. 3.

Specifically, as shown in fig. 2, the anoxic ecological filter 2 includes a vegetable layer 7, a fine sand layer 8, a coarse sand layer 9, a rattan cotton layer 10, a first carbon powder layer 11, a biological filler layer 12, a second carbon powder layer 13, a coarse stone layer 14 and a filter cloth layer 15, which are sequentially laid from top to bottom, the vegetable layer 7 at the top is provided with a water distribution pipe 16 for water inlet, a water outlet pipe 17 is arranged below the filter cloth layer 15 at the bottom, the water distribution pipe 16 and the water outlet pipe 17 are uniformly provided with water holes, and sewage is filtered layer by layer from top to bottom and finally discharged from the water outlet pipe 17.

In this embodiment, the vegetation layer 7 is a water-purifying plant, generally used are plants such as grassiness and canna, and the water-purifying plant has the functions of being suitable for long-term water growth and capable of rapidly and massively absorbing phosphorus, and can prevent blockage. Meanwhile, the fine sand layer 8 and the coarse sand layer 9 are respectively made of gravels with the outer diameters of 3-5mm and 1-3mm, and the whole layer is uniformly laid.

In addition, the rattan cotton layer 10 is made of biochemical cotton, is mainly used for culturing nitrobacteria, decomposes toxic NH3/NH4 and NO2 in sewage, converts the toxic NH3/NH4 and NO2 into nontoxic NO3, can improve water quality and improve the survival rate of fishes, is a filtering material with physical and biochemical filtering effects, has good elasticity and large surface area, is not easy to damage, and can effectively filter impurities in water. The first carbon powder layer 11 and the second carbon powder layer 13 are both mixed with fine sand, and the carbon powder is 100-mesh and 500-mesh activated carbon powder.

In addition, the biological filler layer 12 comprises biological biofilm-forming filler and particulate matter, the particulate matter is plastic particles or ceramsite, the particulate matter is spherical structure, the outer diameter is 50-150mm, the particulate matter is selected according to actual conditions, and water storage materials such as sponge and the like are embedded in the particulate matter and store water for microorganisms. The rough stone layer 14 is stone particles with the outer diameter of 20-40mm, and the filter cloth layer 15 is polyester filter cloth with the density of 500g/m 3.

In this embodiment, the aerobic ecological filter 3 is similar to the anoxic ecological filter 2 in structure, but the aerobic ecological filter 3 further includes an air distribution system, the air distribution system includes a first blower 18 and an air inlet pipe 19, the air inlet pipe 19 is horizontally disposed below the filter cloth layer 15, the air inlet pipe 19 is uniformly provided with air holes, and the air inlet pipe is externally communicated with the first blower 18 for aerating the aerobic ecological filter 3.

Further, the reflux pool 4 is provided with a reflux pump 24 for pumping and refluxing water to the anoxic ecological filter pool 2, and the water is circularly filtered and purified to remove organic pollutants and nitrate nitrogen in the sewage. Most of nitrogen in the sewage exists in the form of ammonia nitrogen, so the content of the ammonia nitrogen is an important water quality index of the sewage, and the nitrogen can be finally converted into nitrogen to be removed through denitrification usually only after the nitrogen is converted into nitrate.

As shown in fig. 4, the filtration and purification principles of the anoxic ecological filter 2, the aerobic ecological filter 3 and the return tank 4 are as follows: the sewage (also called raw water) to be treated firstly enters the anoxic ecological filter 2 through the water inlet pipe, and simultaneously the raw water also enters the aerobic ecological filter 3. The air distribution system in the aerobic ecological filter 3 continuously ventilates, and after a period of aeration, a certain amount of nitrate is generated in the water, so that the return tank 4 returns the nitrified liquid from the aerobic ecological filter 3 to the anoxic ecological filter 2.

The anoxic ecological filter 2 and the aerobic ecological filter 3 of the embodiment are filled with a plurality of ecological fillers, including a vegetable layer 7, a fine sand layer 8, a coarse sand layer 9, a rattan cotton layer 10, a first carbon powder layer 11, a biological filler layer 12, a second carbon powder layer 13, a coarse stone layer 14 and a filter cloth layer 15, wherein water accounts for relatively less, and only the gaps among the fillers account for about 30-50%. The traditional anoxic tank and the aerobic tank are only provided with biological filler and water, and the water accounts for most of the traditional anoxic tank and the traditional aerobic tank, so that a large amount of sludge can be generated in the purification treatment process, and secondary pollution is easily caused.

Because the biological filler is arranged in the anoxic ecological filter tank 2 and the microorganisms of anoxic anaerobes are attached to the biological filler and grow, the microorganisms can utilize organic matters in raw water as a carbon source to reduce nitrifying liquid containing nitrate which is pumped from the aerobic ecological filter tank 3 to the anoxic ecological filter tank 2 through the return tank 4, so that nitrogen in the nitrate is finally converted into nitrogen to be removed, namely, a denitrification process is carried out. At the same time, the organic matter in the raw water is converted into carbon dioxide or water, thereby reducing the concentration of Chemical Oxygen Demand (COD) in the water. The anaerobic reaction unit is subjected to denitrification treatment, and the denitrification treatment needs to consume organic matters, so that COD can be further reduced. The water with the reduced chemical oxygen demand enters the aerobic ecological filter 3.

In the aerobic ecological filter tank 3, nitrifying bacteria convert ammonia nitrogen in raw water into nitrate nitrogen in an aerobic environment, so that the ammonia nitrogen concentration is reduced on one hand, and preparation is also made for the denitrification process of the anoxic ecological filter tank 2 on the other hand, namely, nitrifying liquid containing nitrate is generated, so that the nitrifying liquid is pumped into the anoxic ecological filter tank 2 for denitrification treatment. During denitrification, nitrogen in nitrate is reduced into nitrogen to escape, so that the total nitrogen content is reduced. In addition, in the aerobic ecological filter 3, the organic matters in the water can be further decomposed by the aerobic bacteria in the biological filler, so that the concentration of Chemical Oxygen Demand (COD) is further reduced. The air distribution system provides oxygen to the aerobic ecological filter 3 through the air inlet pipe 19, and the oxygen is dispersed into small bubbles through air holes on the surface of the air inlet pipe 19 and is transmitted to water. Because the aerobic biofilter is internally provided with biological fillers which are used as carriers for the growth of microorganisms, the microorganisms further decompose organic matters in water in an aerobic environment, thereby further reducing the concentration of Chemical Oxygen Demand (COD). The water treated in the aerobic ecological filter tank 3 contains part of nitrate generated in the tank, so that part of water flows back into the anoxic ecological filter tank 2 through the return tank 4 to perform denitrification in the anoxic ecological filter tank 2 and is reduced into nitrogen, and the whole process is performed circularly.

Meanwhile, the ecological filler layers of the anoxic ecological filter tank 2 and the aerobic ecological filter tank 3 respectively filter and purify raw water to eliminate impurities and organic pollutants in the water.

Further, as shown in fig. 5, the magnetic separation tank 5 includes a primary mixing tank 25, a secondary mixing tank 26, a tertiary mixing tank 27, and a sedimentation tank 28, which are connected in a primary manner. The magnetic coagulating sedimentation separation process is that magnetic powder is synchronously added in the common coagulating sedimentation process to be flocculated and combined with pollutants into a whole so as to enhance the coagulation and flocculation effects and ensure that the generated floc has higher density and stronger performance, thereby achieving the purpose of high-speed sedimentation. Compared with the traditional process, the high-speed sedimentation process has the advantages of high speed, high efficiency, small occupied area, small investment and the like.

The first-stage mixing tank 25, the second-stage mixing tank 26 and the third-stage mixing tank 27 are respectively and independently provided with a dosing pump 29 and a stirring paddle 31, the dosing pumps 29 of the first-stage mixing tank 25, the second-stage mixing tank 26 and the third-stage mixing tank 27 are respectively used for feeding prepared coagulant, magnetic powder and flocculant, sewage to be treated firstly enters the first-stage mixing tank of the treatment device, the coagulant PAC is fed into the first-stage mixing tank 25 and is fully mixed with the magnetic powder, then the sewage enters the second-stage mixing tank 26, is mixed and flocculated with the magnetic powder, then enters the third-stage mixing tank 27 and reacts with the flocculant PAM added in the third-stage mixing tank, and is coagulated to generate larger floc particles and then enters the sedimentation tank 28. The stirring paddles 31 in the first-stage mixing tank 25, the second-stage mixing tank 26 and the third-stage mixing tank 27 are used for accelerating the mixing of the sewage and the various medicaments. The magnetic powder is added in the coagulating sedimentation, so that the floc generated by coagulation is effectively combined with the magnetic powder, and the specific gravity of the magnetic powder is 5.2-5.3, thereby greatly increasing the specific gravity of the coagulating floc and greatly accelerating the sedimentation speed of the floc.

In addition, the sedimentation tank 28 is provided with a mud scraper 30, the mud scraper 30 is provided with an impeller type rotating rod 32, the bottom of the sedimentation tank 28 is of an inclined plane structure with a low middle part and a high periphery, the impeller type rotating rod 32 is matched with the inclined plane, and the center of the bottom of the sedimentation tank 28 is communicated with a mud pump 33 for sludge discharge treatment. Along with the rotation of the impeller type rotating rod 32, floc particles and sludge are gathered at a lower central position under the action of gravity, and are pumped out by a sludge pump 33 for discharge or recycling.

In the magnetic separation tank 5, sewage sequentially passes through the three mixing tanks, is mixed with various medicaments to form larger floc particles, finally enters the sedimentation tank 28 for rapid sedimentation, is promoted by the mud scraper 30 to complete separation, and effluent enters the clean water tank 6.

In the detailed description of the embodiments, various technical features may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

It should be understood that the above-described embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the embodiments of the present invention. Other variations and modifications will be apparent to persons skilled in the art in light of the above description. And are neither required nor exhaustive of all embodiments. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention should be included in the protection scope of the claims of the present invention.

Claims

1. The utility model provides a multistage sewage deepening processing system, includes catch basin (1), oxygen deficiency ecological filter (2), good oxygen ecological filter (3), backward flow pond (4), magnetic separation pond (5) and clean water basin (6) that communicate in proper order, its characterized in that: the anoxic ecological filter tank (2) comprises a vegetable layer (7), a fine sand layer (8), a coarse sand layer (9), a rattan cotton layer (10), a first carbon powder layer (11), a biological filler layer (12), a second carbon powder layer (13), a coarse stone layer (14) and a filter cloth layer (15) which are sequentially laid from top to bottom, wherein the vegetable layer (7) is provided with a water distribution pipe (16) for water inlet, a water outlet pipe (17) is arranged below the filter cloth layer (15), and water holes are uniformly formed in the water distribution pipe (16) and the water outlet pipe (17);

the aerobic ecological filter (3) is similar to the anoxic ecological filter (2) in structure, and the aerobic ecological filter (3) further comprises an air distribution system.

2. The multistage advanced wastewater treatment system according to claim 1, wherein: the vegetable layer (7) is a water purification plant, and the rattan cotton layer (10) is used for culturing nitrifying bacteria; the first carbon powder layer (11) and the second carbon powder layer (13) are mixed with fine sand.

3. The multistage advanced wastewater treatment system according to claim 2, wherein: the biological filler layer (12) is formed by mixing biological film-forming filler and particles, and the particles are plastic particles or ceramic particles; the particles are spherical structures, and water storage materials are embedded in the particles.

4. The multistage advanced wastewater treatment system according to claim 3, wherein: the air distribution system comprises a first air blower (18) and an air inlet pipe (19), the air inlet pipe (19) is horizontally arranged below the filter cloth layer (15), and air holes are uniformly formed in the air inlet pipe (19); the inlet air is externally connected to a first blower (18).

5. The multistage advanced wastewater treatment system according to any one of claims 1 to 4, wherein: the water collecting tank (1) comprises a first water tank (20) and a second water tank (21) which are arranged side by side, the bottoms of the first water tank (20) and the second water tank (21) are communicated, the first water tank (20) is provided with a grid (22), and the second water tank (21) is provided with a lifting pump (23) which is used for pumping and draining water to the oxygen-poor ecological filter tank (2).

6. The multistage advanced wastewater treatment system according to claim 5, wherein: the reflux pool (4) is provided with a reflux pump (24) for pumping and refluxing water to the anoxic ecological filter pool (2).

7. The multistage advanced wastewater treatment system according to claim 6, wherein: magnetic separation pond (5) mix pond (25), second grade including the one-level of once intercommunication and mix pond (26), tertiary mixed pond (27) and sedimentation tank (28), one-level mixed pond (25), second grade mix pond (26), tertiary mixed pond (27) all independently are equipped with dosing pump (29), sedimentation tank (28) are equipped with mud scraper (30).

8. The multistage advanced wastewater treatment system according to claim 7, wherein: the primary mixing tank (25), the secondary mixing tank (26) and the tertiary mixing tank (27) are respectively provided with a stirring paddle (31), and each dosing pump (29) is respectively provided with a coagulant, magnetic powder and a flocculant.

9. The multistage advanced wastewater treatment system according to claim 8, wherein: the mud scraper (30) is provided with an impeller type rotating rod (32), the bottom of the sedimentation tank (28) is of an inclined plane structure with a low middle part and high periphery, and the impeller type rotating rod (32) is matched with the inclined plane.

10. The multistage advanced wastewater treatment system according to claim 9, wherein: the center of the bottom of the sedimentation tank (28) is communicated with a sludge discharge pump (33) for sludge discharge treatment.