CN114956325A

CN114956325A - Sewage treatment system

Info

Publication number: CN114956325A
Application number: CN202110193237.6A
Authority: CN
Inventors: 秦升益; 徐志通; 张丹丹; 何贝贝
Original assignee: Beijing Renchuang Technology Development Co ltd
Current assignee: Beijing Renchuang Technology Development Co ltd
Priority date: 2021-02-20
Filing date: 2021-02-20
Publication date: 2022-08-30

Abstract

The invention provides a sewage treatment system, comprising: the anaerobic tank, the anoxic tank, the aerobic tank and the sedimentation tank are communicated in sequence; the first return channel is communicated with the anoxic tank and the anaerobic tank; the second return channel is communicated with the anoxic tank and the aerobic tank; and the third return channel is communicated with the sedimentation tank and the anoxic tank. The technical scheme of the application effectively solves the problem that the sewage treatment system in the related technology has weak nitrogen and phosphorus removal capability.

Description

Sewage treatment system

Technical Field

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

Background

In recent years, the urbanization development speed of China is continuously accelerated, the environmental protection is increasingly emphasized, the discharge standard of urban sewage treatment plants is stricter, the requirements of the sewage treatment plants and the reclaimed water plants on related standards are very urgent through further upgrading and modification, and correspondingly, the sewage treatment technology is further improved and perfected to meet great driving force and social requirements.

In the related art, by A ² the/O process treats sewage. A. the ² The process flow of the/O process is as follows: after biochemical reaction is completed, sludge is deposited in a sedimentation tank, and treated water is discharged. A. the ² The simplest synchronous denitrification and dephosphorization process can be called on an O process system, and the total water retention time is less than that of other similar processes. Under the condition of alternate anaerobic, anoxic and aerobic operation, the filamentous fungi can not be propagated in large quantity and the worry of sludge bulking is avoided. The sludge has high phosphorus concentration and high fertilizer efficiency. In the operation of the whole system, dosing is not needed, the anaerobic zone and the anoxic zone only need to be stirred slightly, dissolved oxygen is not needed to be added, and the operation cost is low. However, the above-mentioned process has no advanced treatment, and the nitrogen and phosphorus removal capability is weak.

Disclosure of Invention

The invention mainly aims to provide a sewage treatment system to solve the problem that the sewage treatment system in the related art is poor in nitrogen and phosphorus removal capability.

In order to achieve the above object, the present invention provides a sewage treatment system comprising: the anaerobic tank, the anoxic tank, the aerobic tank and the sedimentation tank are communicated in sequence; the first return channel is communicated with the anoxic tank and the anaerobic tank; the second return channel is communicated with the anoxic tank and the aerobic tank; and the third return channel is communicated with the sedimentation tank and the anoxic tank.

Further, sewage treatment system still includes first inlet channel, the second inlet channel, third inlet channel and fourth inlet channel, first inlet channel and anaerobism pond intercommunication, second inlet channel intercommunication anaerobism pond and oxygen deficiency pond, third inlet channel intercommunication oxygen deficiency pond and good oxygen pond, good oxygen pond of fourth inlet channel intercommunication and sedimentation tank, sewage gets into sewage treatment system by first inlet channel, and loop through the anaerobism pond, the second inlet channel, the oxygen deficiency pond, good oxygen pond and sedimentation tank, first backward flow passageway intercommunication oxygen deficiency pond and first inlet channel, second backward flow passageway intercommunication fourth inlet channel and second inlet channel, third backward flow passageway intercommunication sedimentation tank and second inlet channel.

Furthermore, fillers are filled in the anaerobic tank, the anoxic tank and the aerobic tank, biochemical reaction well chambers are arranged in the anaerobic tank and the anoxic tank, the biochemical reaction well chambers are built by silica sand building blocks, a first fixing support for hanging soft polyester fillers is arranged in the biochemical reaction well chambers in the anaerobic tank, a second fixing support for hanging soft polyester fillers is arranged in the biochemical reaction well chambers in the anoxic tank, aerobic suspension fillers are filled in the aerobic tank, and the filling rate of the aerobic suspension fillers is 30-60%.

Further, hydrophilic factors are blended into a filler base material of the aerobic suspended filler in the aerobic tank, and the external dimension of the aerobic suspended filler is

The configuration density of the aerobic suspended filler is in the range of 0.94g/cm ³ -0.97g/cm ³ ，

The oxidation rate of the organic matter of the aerobic suspended filler is more than or equal to 10 g.COD/m ² /d。

Furthermore, the dissolved oxygen content DO in the aerobic pool is 2 mg/L-2.5 mg/L, the dissolved oxygen content DO in the anoxic pool is 0.2 mg/L-0.5 mg/L, the dissolved oxygen content DO in the anaerobic pool is less than or equal to 0.2mg/L, the aerobic pool supplies air by using an air compressor, an upflow aeration pipe of the air compressor aerates and oxygenizes, the anoxic pool supplements dissolved oxygen from the reflux liquid of the aerobic pool by using a nitrifying liquid internal reflux pipe, and the anaerobic pool extracts the dissolved oxygen from the reflux liquid of the anoxic pool by using a denitrifying liquid internal reflux pipe.

Further, the inside sediment device and the first drain port of being provided with of sedimentation tank, first drain port are located the below of sediment device, and sewage treatment system still includes the delivery port, and the delivery port is located the top of sediment device.

Further, the flow rate through the water inlet of the first water inlet channel is Q _m The flow rate in the first return passage is Q _B The flow rate in the second return passage is Q _A The flow rate in the third return passage is Q _R ，Q _A ＝1.5Q _m ～2.5Q _m ，Q _B ＝1.5Q _m ～2.5Q _m ，Q _R ＝Q _m 。

Furthermore, the water inlet of the first water inlet channel is positioned above the first water inlet channel, the water outlet of the first water inlet channel is positioned below the first water inlet channel, the water inlet of the second water inlet channel is positioned above the second water inlet channel, the water outlet of the second water inlet channel is positioned below the second water inlet channel, the water inlet of the third water inlet channel is positioned above the third water inlet channel, the water outlet of the third water inlet channel is positioned below the third water inlet channel, the water inlet of the fourth water inlet channel is positioned above the fourth water inlet channel, and the water outlet of the fourth water inlet channel is positioned below the fourth water inlet channel.

Furthermore, the bottoms of the second water inlet channel, the third water inlet channel and the fourth water inlet channel are provided with second sewage outlets.

Further, the bottom of the sedimentation tank is conical, and the first sewage discharge port is positioned at the bottom of the cone.

By applying the technical scheme of the invention, the anoxic tank is communicated with the anaerobic tank, the aerobic tank is communicated with the anoxic tank, and the sedimentation tank is communicated with the aerobic tank. The first return channel is communicated with the anoxic tank and the anaerobic tank, the second return channel is communicated with the anoxic tank and the aerobic tank, and the third return channel is communicated with the sedimentation tank and the anoxic tank. Through the first backflow channel, the second backflow channel and the third backflow channel, sewage in the treatment process is effectively and constantly refluxed, and then repeated treatment of the sewage is achieved, and the content of nitrogen and phosphorus in the sewage is effectively reduced in the treatment process. Therefore, the technical scheme of the application effectively solves the problem that the sewage treatment system in the related technology has weak nitrogen and phosphorus removal capability. In addition, the technical scheme of the application is provided with the first backflow channel, the second backflow channel and the third backflow channel, the arrangement mode is simple, the processing difficulty is low, and the production cost can be effectively reduced.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a schematic cross-sectional view of an embodiment of a wastewater treatment system according to the invention;

FIG. 2 shows a schematic plan view of an embodiment of the wastewater treatment system of FIG. 1; and

FIG. 3 shows a schematic flow diagram of an embodiment of the wastewater treatment system of FIG. 1.

Wherein the figures include the following reference numerals:

1. an anaerobic tank; 2. an anoxic tank; 3. an aerobic tank; 4. a sedimentation tank; 5. a second return channel; 6. a first return channel; 7. a third return channel; 8. a water inlet; 9. a water outlet; 10. a second sewage draining outlet; 11. a first water inlet channel; 12. a second water inlet channel; 13. a third channel; 14. a fourth water inlet channel; 16. a first fixed bracket; 17. a second fixed bracket; 19. an air compressor; 22. a precipitation device; 41. a first drain outlet.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. The following description of at least one exemplary embodiment is merely illustrative in nature and is in no way intended to limit the invention, its application, or uses. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments according to the present application. As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

The relative arrangement of the components and steps, the numerical expressions and numerical values set forth in these embodiments do not limit the scope of the present invention unless specifically stated otherwise. Meanwhile, it should be understood that the sizes of the respective portions shown in the drawings are not drawn in an actual proportional relationship for the convenience of description. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art may not be discussed in detail, but are intended to be part of the specification where appropriate. In all examples shown and discussed herein, any particular value should be construed as merely illustrative, and not limiting. Thus, other examples of the exemplary embodiments may have different values. It should be noted that: like reference numbers and letters refer to like items in the following figures, and thus, once an item is defined in one figure, further discussion thereof is not required in subsequent figures.

Compared with the prior art, the technical scheme of the embodiment adds a backflow channel, namely water flows from the anoxic tank 2 to the water inlet of the anaerobic tank 1, and the flow rate is Q _B (ii) a The original outlet of the active sludge return channel led out from the bottom of the sedimentation tank 4 is connected with the water inlet of the anoxic tank 2 from the anaerobic tank 1, and the flow rate is Q _R . Instead, 3 return channels are provided, namely a first return channel 6, a second return channel 5 and a third return channel 7: the water flows out from the aerobic tank 3 to the water inlet of the anoxic tank 2 with the flow rate of Q _A And is not changed.

As shown in fig. 1 to 3, in the present embodiment, the sewage treatment system includes: the anaerobic tank 1, the anoxic tank 2, the aerobic tank 3 and the sedimentation tank 4 are sequentially communicated with the first return channel 6, the second return channel 5 and the third return channel 7. The first return channel 6 is communicated with the anoxic tank 2 and the anaerobic tank 1. The second return channel 5 is communicated with the anoxic tank 2 and the aerobic tank 3. The third return channel 7 is communicated with the sedimentation tank 4 and the anoxic tank 2.

By applying the technical scheme of the embodiment, the anoxic tank 2 is communicated with the anaerobic tank 1, the aerobic tank 3 is communicated with the anoxic tank 2, and the sedimentation tank 4 is communicated with the aerobic tank 3. The first return passage 6 is communicated with the anoxic tank 2 and the anaerobic tank 1, the second return passage 5 is communicated with the anoxic tank 2 and the aerobic tank 3, and the third return passage 7 is communicated with the sedimentation tank 4 and the anoxic tank 2. Through the first return channel 6, the second return channel 5 and the third return channel 7, the sewage in the treatment process is effectively and continuously returned, so that the repeated treatment of the sewage is realized, and the content of nitrogen and phosphorus in the sewage is effectively reduced in the treatment process. Therefore, the technical scheme of the application effectively solves the problem that the sewage treatment system in the related technology has weak nitrogen and phosphorus removal capability. In addition, the technical scheme of the embodiment is provided with the first backflow channel, the second backflow channel and the third backflow channel, so that the arrangement mode is simple, the processing difficulty is low, and the production cost can be effectively reduced.

In this embodiment, when the reflux ratio R of the first reflux channel 6 is between 150% and 200%, and R is 150%, the phosphorus removal rate is between 60% and 69%, the effluent quality reaches the national first-class a standard, and when R is 200%, the phosphorus removal rate reaches 91%, and the effluent quality reaches the IV-class ground water standard. Meanwhile, when the reflux ratio R of the first reflux channel 6 is between 150% and 200%, the nitrogen removal rate reaches 74%, and the effluent quality reaches the IV-class ground water standard.

The mixed liquor enters an aerobic section from the anoxic section into an aeration tank (aerobic tank 3), the function of the aerobic section is various, and a plurality of reactions such as COD removal, nitrification, phosphorus absorption and the like are all carried out in the section. Contained in the mixed liquor

Excess phosphorus is contained in the sludge, and BOD biochemical oxygen demand (or COD chemical oxygen demand) in the sewage is removed.

Under the condition that the anaerobic tank 1, the anoxic tank 2 and the aerobic tank 3 alternately operate, filamentous fungi cannot propagate in large quantity, and the sludge bulking is avoided. The sludge has high phosphorus concentration and high fertilizer efficiency. The chemical dosing is not needed during the operation, the anaerobic tank 1 and the anoxic tank 2 only need to be stirred slightly without increasing the dissolved oxygen, and the operation cost is low. During operation, the inlet water of the sedimentation tank 4 needs to maintain certain dissolved oxygen, so that the retention time is reduced, the anaerobic state is prevented, the phosphorus release phenomenon of the sludge is prevented, but the concentration of the dissolved oxygen is not too high, and the influence of the circulating mixed liquid on the anoxic reaction zone is prevented.

The sedimentation tank 4 is an upflow inclined tube sedimentation tank, the SS of the effluent is less than or equal to 5mg/L (SS is the concentration of suspended solids), or a sand filter is selected.

As shown in fig. 1 and 2, in the present embodiment, the sewage treatment system further includes a first water inlet channel 11, a second water inlet channel 12, a third water inlet channel 13 and a fourth water inlet channel 14, sewage firstly enters the first water inlet channel 11, enters the anaerobic tank 1 from the first water inlet channel 11, enters the second water inlet channel 12 from the anaerobic tank 1, enters the anoxic tank 2 from the second water inlet channel 12, enters the third water inlet channel 13 from the anoxic tank 2, enters the aerobic tank 3 from the third water inlet channel 13, enters the fourth water inlet channel 14 from the aerobic tank 3, and enters the sedimentation tank 4 from the fourth water inlet channel 14, such an arrangement can prevent sewage from directly flowing into the anaerobic tank 1, the anoxic tank 2, the aerobic tank 3 and the sedimentation tank 4, and can play a role of buffering, and sewage can be precipitated in the first water inlet channel 11, the second water inlet channel 12, the third water inlet channel 13 and the fourth water inlet channel 14, thus, the effect of purifying the sewage can be indirectly improved.

As shown in fig. 1 and 2, in this embodiment, the anaerobic tank 1, the anoxic tank 2 and the aerobic tank 3 are filled with fillers, the anaerobic tank 1 and the anoxic tank 2 are biochemical reaction wells, the biochemical reaction wells are built by silica sand blocks, a first fixing bracket 16 for hanging soft dacron fillers is arranged in the biochemical reaction well in the anaerobic tank 1, a second fixing bracket 17 for hanging soft dacron fillers is arranged in the biochemical reaction well in the anoxic tank 2, and aerobic suspension fillers are filled in the aerobic tank 3, wherein the filling rate of the aerobic suspension fillers is between 30% and 60%. The arrangement of the first fixing support 16 and the second fixing support 17 can enable the filler to be placed on the first fixing support, so that the biofilm formation area of the sewage biochemical pool is obviously increased, and good survival conditions are provided for various strains required by the sewage biochemical process. And different fillers are filled in the biochemical reaction well chambers with different functions, so that good survival conditions can be provided for different strains in a targeted manner.

It should be noted that the biochemical reaction well chamber built by the waterproof silica sand building blocks is a silica sand well body.

As shown in FIG. 1 and FIG. 2, in this embodiment, the hydrophilic factor is blended into the filler base material of the aerobic suspended filler in the aerobic tank 3, and the external dimension of the aerobic suspended filler is

The configuration density of the aerobic suspended filler is 0.94g/cm ³ -0.97g/cm ³ ，

The oxidation rate of the organic matters of the aerobic suspended filler is more than or equal to 10g COD per square meter per day. The aerobic suspended filler has the preferable external dimension which is within the range

All can be used in the same way. Cross-partition sheets are arranged in the aerobic suspended filler; the material is made of HDPE (high-density polyethylene) or PP (polypropylene) based propylene and is formed by injection molding. Hydrophilic factors are blended into the filler base material of the aerobic suspended filler, so that the growth of microorganisms in water is facilitated; the density of the filler after film hanging is close to that of water, and the filler and the sewage are in a completely mixed state when the sewage treatment tank is aerated. The aerobic suspension filler is a high-density polyethylene suspension carrier filler for water treatment.

The aerobic suspended filler is arranged according to the density

Where ρ is _a Is the density of the filler in g/cm ³ M is a fillerMass of the material in kg, V _a Is the volume of the filler in m ³ . The nitrification rate of the aerobic suspended filler after the carrier is filmed means that the nitrification rate of the biological film for enhancing the nitrification should be greater than or equal to

And (3) obtaining the organic matter removal rate after the filler is coated by calculation by utilizing the curve and the effective adding surface area through test measurement results and drawing a COD concentration-time change curve.

As shown in the figure 1 and the figure 2, in the embodiment, the dissolved oxygen content DO in the aerobic tank 3 is between 2mg/L and 2.5mg/L, the dissolved oxygen content DO in the anoxic tank 2 is between 0.2mg/L and 0.5mg/L, the dissolved oxygen content DO in the anaerobic tank 1 is less than or equal to 0.2mg/L, the aerobic tank 3 supplies air by using an air compressor 19, an upflow aeration pipe of the air compressor 19 aerates and oxygenizes, the anoxic tank 2 supplements dissolved oxygen from the reflux liquid in the aerobic tank 3 by using a nitrifying liquid internal reflux pipe, and the anaerobic tank 1 extracts the dissolved oxygen from the reflux liquid in the anoxic tank 2 by using a denitrifying liquid internal reflux pipe. The excessively high dissolved oxygen content DO of the aerobic tank can inhibit the nitrification of the nitrifying bacteria, destroy the low dissolved oxygen content DO states of the anaerobic tank and the anoxic tank, limit the growth rate of the nitrifying bacteria due to the excessively low dissolved oxygen content DO, and seriously affect the denitrification effect of the sewage. The air compressor 19 can efficiently inflate the aerobic tank 3 and further oxygenate the aerobic tank 3 through the upflow aeration tube. Such an embodiment is simple and easy to set up. Of course, other devices can be used to replace the air compressor, as long as the aeration and oxygenation can be performed in the aerobic tank 3. The nitrifying liquid internal reflux pipe is a second reflux channel 5, and the denitrifying liquid internal reflux pipe is a first reflux channel 1. It should be noted that the upflow aerator pipe is an aerator which flows upward, and the aerator is selected according to the industry standard CJ/T264-2018.

As shown in FIGS. 1 and 2, in the present embodiment, the sedimentation tank 4 is provided thereinThe sewage treatment system is provided with a sedimentation device 22 and a first sewage discharge port 41, wherein the first sewage discharge port 41 is positioned below the sedimentation device 22, the sewage treatment system also comprises a water outlet 9, and the water outlet 9 is positioned above the sedimentation device 22. The settling device 22 is

The polypropylene inclined tube is filled with a filler,

the polypropylene inclined tube filler can further precipitate impurities in water, so that the sewage treatment is more complete. After the sewage is treated and passes through the settling device 22, a complete sewage purification process is realized, and then the sewage can be discharged.

As shown in fig. 1 to 3, in the present embodiment, the flow rate through the inlet 8 of the first inlet channel 11 is Q _m The flow rate in the first return passage 6 is Q _B The flow rate in the second return passage 5 is Q _A The flow rate in the third return passage 7 is Q _R ，Q _A ＝1.5Q _m ～2.5Q _m ，Q _B ＝1.5Q _m ～2.5Q _m ，Q _R ＝Q _m . Selecting a suitable Q _A 、Q _B 、Q _R The method is extremely important for the denitrification effect of the sewage. Q _A 、Q _B Too large a reflux pump requiring high power, increasing energy consumption, conversely, Q _A 、Q _B When smaller, the denitrification efficiency is reduced. Q _R When the time is too small, the load of the anaerobic tank is increased, and the efficiency of each section of biochemical reaction tank is influenced; q _R If the phosphorus-accumulating bacteria is too large, the effect of releasing phosphorus by the phosphorus-accumulating bacteria is influenced, and the removal rate of total phosphorus is reduced.

As shown in fig. 1 and 2, in the present embodiment, the water inlet 8 of the first water inlet channel 11 is located above the first water inlet channel 11, the water outlet of the first water inlet channel 11 is located below the first water inlet channel 11, the water inlet of the second water inlet channel 12 is located above the second water inlet channel 12, the water outlet of the second water inlet channel 12 is located below the second water inlet channel 12, the water inlet of the third water inlet channel 13 is located above the third water inlet channel 13, the water outlet of the third water inlet channel 13 is located below the third water inlet channel 13, the water inlet of the fourth water inlet channel 14 is located above the fourth water inlet channel 14, and the water outlet of the fourth water inlet channel 14 is located below the fourth water inlet channel 14. The above arrangement enables impurities in the polluted water to be continuously deposited in the interiors of the first, second, third and fourth

water inlet channels

11, 12, 13 and 14. The density of impurity is greater than water, and the water level is in the top of impurity, therefore this mode of setting up can make sewage purification's effect better, more thorough.

In the process, water outlet or sludge return channels, a water inlet from the aerobic tank 3 to the anoxic tank 2 and a flow rate Q are arranged between each stage of biochemical treatment reactor and the sedimentation tank 4 _A . From the water outlet of the anoxic tank 2 to the water inlet of the anaerobic tank 1, the flow rate Q _B . Active sludge is led out from the bottom of the sedimentation tank 4 and flows back to the water inlet of the anoxic tank 2, and the flow rate Q is _R 。

The bottoms of the second water inlet channel 12, the third water inlet channel 13 and the fourth water inlet channel 14 are all provided with a second sewage draining outlet 10. The second sewage draining exit 10 can discharge impurities in the second water inlet channel 12, the third water inlet channel 13 and the fourth water inlet channel 14, so that the whole sewage treatment system is kept clean, and the purifying effect can be improved.

The bottom of the sedimentation tank 4 is conical, and the first drain port 41 is located at the bottom of the cone. The tapered bottom is convenient to arrange and enables sludge to be easily discharged.

The total hydraulic retention time HRT of the biochemical reaction is 13h, wherein the HRT of the R1 anaerobic section in the anaerobic tank 1 is 3h, the HRT of the R2 anoxic section in the anoxic tank 2 is 3h, the HRT of the R3 aerobic section in the aerobic tank 3 is 7h, and the HRT of the R4 sedimentation tank in the sedimentation tank 4 is 3.6 h; mud retention time HRT 15 d. Generally, it is considered that HRT is long, which is advantageous for removing COD. However, for the HRT with too long anaerobic tank, the sludge in the anaerobic tank 1 expands, and the flow speed is higher due to too short anaerobic tank, so that the loss of activated sludge is easy to cause; compared with the aerobic tank 3, the too long HRT affects the phosphorus release effect of the sludge and increases the discharge amount of the sludge, and the too short HRT causes insufficient nitrification process in the sewage and is not beneficial to denitrification.

The pH value of the optimal pH value for sewage treatment is 6.5-8.5, and in the range, the microorganisms are suitable for normal life, and if the pH value deviates too much, the catalytic function of the enzyme system of the microorganisms can be weakened, even the microorganisms die. The pH value can be adjusted by adding medicament.

The flow state of the sewage in the technical scheme of the embodiment is basically approximate to that of a plug flow type, the sewage flows in from the anaerobic tank 1, and then flows out through the anoxic tank 2, the aerobic tank 3 and the sedimentation tank 4 in sequence, sludge is precipitated, part of the sludge flows back, and redundant discharge or drying treatment is carried out.

The structure form of the water tank fixed by the silica sand sewage underground water treatment tank is as follows: the silica sand permeable module well is used as a water storage unit to form a hexagonal honeycomb structure bearing structure, and the upper part of the shaft is a water tank top plate to bear the soil pressure of the ground.

The design specification GB50003-20011 of the silica sand well body and the building block execution masonry structure is recommended, the service life is 50 years, and the service environment category of the pool is as follows: and (2) class.

The technical scheme of the embodiment adopts a two-stage biological selective denitrification nitrogen and phosphorus removal process which is innovated and researched based on the AAO theory, and is mainly different from the traditional AAO process in that a denitrification liquid internal reflux channel is added and is led out from an anoxic tank 2 to an anaerobic tank 1. Meanwhile, the outlet of the sludge return channel is changed to the anoxic tank 2. The problem of interference of nitrate in the returned sludge of the traditional AAO process on anaerobic phosphate-releasing bacteria is solved in the aspect of function. And the anaerobic-anoxic alternate operation mode is favorable for enriching denitrifying phosphorus-releasing bacteria of the strengthening system.

The process can theoretically save 50% of carbon source requirement, reduce 30% of oxygen demand, reduce 50% of residual activated sludge yield and effectively control sludge bulking. The denitrification liquid backflow ensures the anaerobic-anoxic circulation of the system, provides conditions for the growth and enrichment of denitrifying phosphorus bacteria, and the control of the denitrification backflow ratio influences the living environment of the denitrifying phosphorus bacteria. The return flow of the denitrification liquid also carries part of NO3-N, NO2-N to the anaerobic tank 1, and the return flow of the denitrification liquid has important significance for sewage denitrification.

Since nitrogen Nitrate (NO) is largely avoided from the process aspect ₃ ) P-PAO (PAO) _S DPB), makes full use of the action of phosphorus-accumulating bacteria, can gather more denitrifying phosphorus-removing bacteria (DPB), and maximizes the synchronous nitrogen and phosphorus removalThe application is. The characteristics improve the pollutant removal efficiency of the process to a great extent, are favorable for improving the effluent quality, reduce the operation energy consumption, and ensure that the effluent quality of a sewage treatment plant reaches the standard, and the effluent quality can reach the first-class A emission standard to the IV-class ground water standard.

In the description of the present invention, it is to be understood that the orientation or positional relationship indicated by the orientation words such as "front, rear, upper, lower, left, right", "lateral, vertical, horizontal" and "top, bottom", etc. are usually based on the orientation or positional relationship shown in the drawings, and are only for convenience of description and simplicity of description, and in the case of not making a reverse description, these orientation words do not indicate and imply that the device or element being referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore, should not be considered as limiting the scope of the present invention; the terms "inner and outer" refer to the inner and outer relative to the profile of the respective component itself.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

It should be noted that the terms "first", "second", and the like are used to define the components, and are only used for convenience of distinguishing the corresponding components, and the terms have no special meanings unless otherwise stated, and therefore, the scope of the present invention should not be construed as being limited.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A wastewater treatment system, comprising:

the anaerobic tank (1), the anoxic tank (2), the aerobic tank (3) and the sedimentation tank (4) are communicated in sequence;

a first return channel (6), wherein the first return channel (6) is communicated with the anoxic tank (2) and the anaerobic tank (1);

the second backflow channel (5), the second backflow channel (5) is communicated with the anoxic tank (2) and the aerobic tank (3);

and the third return channel (7), and the third return channel (7) is communicated with the sedimentation tank (4) and the anoxic tank (2).

2. The wastewater treatment system according to claim 1, further comprising a first water inlet channel (11), a second water inlet channel (12), a third water inlet channel (13) and a fourth water inlet channel (14), wherein the first water inlet channel (11) is communicated with the anaerobic tank (1), the second water inlet channel (12) is communicated with the anaerobic tank (1) and the anoxic tank (2), the third water inlet channel (13) is communicated with the anoxic tank (2) and the aerobic tank (3), the fourth water inlet channel (14) is communicated with the aerobic tank (3) and the sedimentation tank (4), wastewater enters the wastewater treatment system from the first water inlet channel (11) and sequentially passes through the anaerobic tank (1), the second water inlet channel (12), the anoxic tank (2), the aerobic tank (3) and the sedimentation tank (4), the first return channel (6) is communicated with the anoxic pond (2) and the first water inlet channel (11), the second return channel (5) is communicated with the fourth water inlet channel (14) and the second water inlet channel (12), and the third return channel (7) is communicated with the sedimentation pond (4) and the second water inlet channel (12).

3. The sewage treatment system according to claim 1, wherein the anaerobic tank (1), the anoxic tank (2) and the aerobic tank (3) are filled with fillers, the anaerobic tank (1) and the anoxic tank (2) are biochemical reaction wells, the biochemical reaction wells are built by silica sand blocks, a first fixing bracket (16) for hanging soft terylene fillers is arranged in the biochemical reaction well in the anaerobic tank (1), a second fixing bracket (17) for hanging soft terylene fillers is arranged in the biochemical reaction well in the anoxic tank (2), the aerobic tank (3) is filled with aerobic suspension fillers, and the filling rate of the aerobic suspension fillers is between 30% and 60%.

4. The wastewater treatment system according to claim 3, wherein the filler base material of the aerobic suspended filler in the aerobic tank (3) is integrated with hydrophilic factors, and the external dimension of the aerobic suspended filler is

The configuration density range of the aerobic suspended filler is 0.94g/cm ³ -0.97g/cm ³ The effective specific surface area of the aerobic suspended filler is more than or equal to 450m ² /m ³ Said

5. The wastewater treatment system according to claim 1, wherein the dissolved oxygen content DO in the aerobic tank (3) is 2 mg/L-2.5 mg/L, the dissolved oxygen content DO in the anoxic tank (2) is 0.2 mg/L-0.5 mg/L, the dissolved oxygen content DO in the anaerobic tank (1) is less than or equal to 0.2mg/L, the aerobic tank (3) is supplied with air by an air compressor (19), an upflow aeration pipe of the air compressor (19) is aerated by oxygenation, the anoxic tank (2) is supplemented with dissolved oxygen from the reflux liquid in the aerobic tank (3) by a nitrifying liquid internal reflux pipe, and the anaerobic tank (1) is used for extracting dissolved oxygen from the reflux liquid in the anoxic tank (2) by a denitrifying liquid internal reflux pipe.

6. The sewage treatment system according to claim 1, wherein a sedimentation device (22) and a first drain outlet (41) are provided inside said sedimentation tank (4), said first drain outlet (41) being located below said sedimentation device (22), said sewage treatment system further comprising a water outlet (9), said water outlet (9) being located above said sedimentation device (22).

7. Sewage treatment system according to claim 2, characterised in that the flow through the inlet (8) of the first inlet channel (11) is Q _m The flow rate in the first return passage (6) is Q _B The flow rate in the second return channel (5) is Q _A The flow rate in the third return channel (7) is Q _R Wherein Q is _A ＝1.5Q _m ～2.5Q _m ，Q _B ＝1.5Q _m ～2.5Q _m ，Q _R ＝Q _m 。

8. Sewage treatment system according to claim 7, characterised in that the inlet opening (8) of the first inlet channel (11) is located above the first inlet channel (11), the water outlet of the first water inlet channel (11) is positioned below the first water inlet channel (11), the water inlet of the second water inlet channel (12) is positioned above the second water inlet channel (12), the water outlet of the second water inlet channel (12) is positioned below the second water inlet channel (12), the water inlet of the third water inlet channel (13) is positioned above the third water inlet channel (13), the water outlet of the third water inlet channel (13) is positioned below the third water inlet channel (13), the water inlet of the fourth water inlet channel (14) is positioned above the fourth water inlet channel (14), the water outlet of the fourth water inlet channel (14) is positioned below the fourth water inlet channel (14).

9. The sewage treatment system according to claim 2, wherein the bottom of said second inlet channel (12), said third inlet channel (13) and said fourth inlet channel (14) are provided with a second sewage drain (10).

10. Sewage treatment system according to claim 6, characterised in that the bottom of the sedimentation tank (4) is conical, and that the first drain opening (41) is located at the bottom of the cone.