CN115385451A

CN115385451A - Two-stage A/O activated sludge process sewage treatment system and process

Info

Publication number: CN115385451A
Application number: CN202210972312.3A
Authority: CN
Inventors: 王舜和; 李子健; 李晓岩; 李凯
Original assignee: Yuxing Environmental Protection Engineering Co ltd
Current assignee: Yuxing Environmental Protection Engineering Co ltd
Priority date: 2022-08-15
Filing date: 2022-08-15
Publication date: 2022-11-25

Abstract

The invention provides a two-stage A/O activated sludge process sewage treatment system and a process, and relates to the technical field of sewage treatment. The device comprises a primary treatment system and a secondary treatment system, wherein the primary treatment system comprises a primary anaerobic tank, a primary anoxic tank, a primary aerobic tank and a primary internal reflux well which are sequentially communicated, and the secondary treatment system comprises a secondary maneuvering tank, a secondary anoxic tank, a secondary aerobic tank and a secondary reflux well which are sequentially communicated; wear to be equipped with the inlet channel between one-level processing system and the second grade processing system, the outside is equipped with the outlet channel, and the outlet channel is through establishing ties the point gate intercommunication of intaking with the second grade mobile pond, is equipped with the outlet channel weir gate in the outlet channel, and the below of inlet channel is equipped with the internal reflux canal, and two-stage good oxygen pond communicates with the entry of two-stage backward flow well respectively, and the export of two-stage backward flow well communicates with the internal reflux canal respectively, and the internal reflux canal flows to the oxygen deficiency pond of two-stage. The switching of the series-parallel mode of the two-stage system is realized by controlling the weir gate and the gate, and the switching of the sewage treatment process when the water quality standard changes is solved.

Description

Two-stage A/O activated sludge process sewage treatment system and process

Technical Field

The invention relates to the technical field of sewage treatment, in particular to a two-stage A/O activated sludge process sewage treatment system and a process.

Background

The rapid development of society and the acceleration of urban industrialization progress do not promote the improvement of the utilization rate of the dampening resources, however, the serious water eutrophication phenomenon is generated along with the development of society. In many countries in the world, a series of measures are also taken to solve the problem of water environment pollution caused by economic development, such as improving the sewage discharge standard, changing the drainage system, perfecting the construction of sewage pipe networks and sewage plants, and the like. How to economically and effectively remove nitrogen and phosphorus in eutrophic sewage and make the water quality reach the standard and discharge becomes a key problem in the sewage treatment industry of China.

In order to achieve the aims of denitrification and dephosphorization of town sewage and standard discharge, an anaerobic/anoxic/aerobic process (A) is adopted ² O) is widely popularized and applied in China. As shown in fig. 1, conventional a ² The sewage in the O process goes through three stages of anaerobic treatment, anoxic treatment and aerobic treatment from water inlet to water outlet, and phosphorus accumulating bacteria, nitrifying bacteria and denitrifying bacteria in the sewage play respective roles in different environments to realize the effects of nitrogen and phosphorus removal. However, A is ² In the aspect of carbon source utilization in the nitrogen and phosphorus removal process of the/O process system, the competitive relationship of denitrifying bacteria and phosphorus accumulating bacteria to the carbon source in sewage exists, so that the nitrogen and phosphorus removal is difficult to meet at the same time, and the anoxic zone is positioned in the middle area of the process, and the denitrification is in a negative position on the carbon source distribution, so that the nitrogen removal effect of the system can be influenced. Tradition A ² Nitrate nitrogen generated in the aerobic zone at the tail end of the O process can directly flow into a subsequent secondary sedimentation tank, so in order to achieve the effect of effective denitrification, the tail end of the aerobic zone is also provided with nitrifying liquid to flow back to remove redundant nitrate nitrogen. However, the nitrate existing in the sludge returned to the anaerobic zone can inhibit the physiological activity of the phosphorus-accumulating bacteria in the anaerobic zone, and the phosphorus removal efficiency is reduced. Therefore, the above disadvantages limit the conventional A ² The wide application of the/O process only applies to sewage plants with low requirements on nitrogen and phosphorus removal.

To meet the more stringent total nitrogen requirements of effluent discharge standards, conventional A ² The transformation process of/O, the "Bardenpho" process, is applied in the conventional A ² The rear end of the/O process is added with an anoxic tank andand a carbon source is added into the anoxic tank. The oxygen-poor tank added at the rear end aims at NO in the mixed liquid flowing from the front-end aerobic tank ₃ And the-N is subjected to denitrification and denitrification under the action of denitrifying bacteria, and a carbon source is added in the anoxic section to provide electrons for denitrification. Meanwhile, the aerobic section additionally arranged at the rear end can oxidize unused carbon sources, improve the DO concentration in effluent mixed liquor and improve the sedimentation performance of sludge in the secondary sedimentation tank. The Bardenpho process provides a better idea for biochemical denitrification, but because a carbon source needs to be added in an anoxic section additionally arranged at the rear end, the adding amount of the carbon source is difficult to control and is often added excessively, the cost for operation is higher.

On the other hand, the existing tradition A in sewage treatment plants ² the/O process is generally designed to be a mode of multi-series parallel operation, and sewage enters each group A respectively ² Processing in an/O processing system. A plurality of series are connected in parallel, so that when part of equipment is overhauled, the rest series can work, and the influence of equipment maintenance on the operation of a sewage treatment plant is reduced. However, in this mode, the wastewater treatment plant lacks flexibility in being exposed to future water discharge standards due to the conventional A ² the/O system is only suitable for sewage plants with low requirements on nitrogen and phosphorus removal, so that the existing biochemical tank needs to be modified or advanced treatment facilities are added after the existing biochemical tank when the sewage plants are upgraded and modified, the engineering investment is increased, and the operation of the sewage plants is inconvenient. In addition, a are connected in parallel in multiple series ² the/O process causes the underground pipeline of the sewage plant to be complicated, is difficult to regulate and control and maintain the pipeline, is inconvenient for the operation of the sewage plant, and has certain difficulty in design, construction and later modification.

Therefore, in view of the deficiencies of the prior art, it is desirable to provide a two-stage a/O activated sludge process and system for treating wastewater that solves the problems set forth above in the background.

Disclosure of Invention

The invention aims to provide a two-stage A/O activated sludge process sewage treatment system and a process, which can provide a solution for the defects in the prior art, utilize a special internal pool type layout structure design,controlling the operation mode of the biochemical pool according to the change of the water quality standard of the inlet water or the water quality standard of the outlet water, at A ² The mode of the/O parallel connection and the mode of the two-stage A/O series connection are switched, so that the problem that sewage plants cannot flexibly deal with different water quantities and different water qualities in different periods or in later lifting is solved.

The embodiment of the invention provides a two-stage A/O activated sludge process sewage treatment system, which comprises a primary treatment system and a secondary treatment system which are arranged in parallel, wherein the primary treatment system comprises a primary anaerobic tank, a primary anoxic tank, a primary aerobic tank and a primary internal return well which are sequentially communicated, the primary anaerobic tank is externally connected with a primary sludge return pipe, the secondary treatment system comprises a secondary maneuvering tank, a secondary anoxic tank, a secondary aerobic tank and a secondary return well which are sequentially communicated, and the secondary maneuvering tank is externally connected with a secondary sludge return pipe; stirrers are arranged in the primary anaerobic tank, the primary anoxic tank, the secondary mobile tank and the secondary anoxic tank;

a water inlet channel is arranged between the primary treatment system and the secondary treatment system in a penetrating manner, two water outlets of the water inlet channel are respectively communicated with the primary anaerobic tank and the secondary mobile tank through a first gate and a second gate, and a water inlet of the water inlet channel is connected with a water inlet pipe;

the water outlets of the primary aerobic pool and the secondary aerobic pool are respectively communicated with the water outlet channel through a first water outlet weir and a second water outlet weir, the water outlet of the water outlet channel is connected with a water outlet pipe, the water outlet channel is communicated with the secondary mobile pool through a series connection water inlet point gate, a water outlet channel weir door is further arranged in the water outlet channel, and the series connection water inlet point gate and the second water outlet weir are separated by the water outlet channel weir door;

the below of inlet channel is equipped with in one-level backward flow canal and second grade backward flow canal, one-level good oxygen pond with second grade good oxygen pond respectively with one-level backward flow well with the entry intercommunication of second grade backward flow well, one-level backward flow well with the export of second grade backward flow well respectively through first backward flow point and second backward flow point with in the one-level backward flow canal with the entry intercommunication of backward flow canal in the second grade, the export of one-level backward flow canal with one-level oxygen deficiency pond intercommunication, the export of second grade backward flow canal respectively with the second grade motor-driven pond with second grade oxygen deficiency pond intercommunication.

In some embodiments of the present invention, at least one of the primary anoxic tank and the secondary anoxic tank is provided.

In some embodiments of the invention, there are three primary anoxic tanks and three secondary anoxic tanks, respectively.

In some embodiments of the invention, the primary anaerobic tank, the primary anoxic tank, the secondary mobile tank, and the secondary anoxic tank are rectangular tank shaped with an aspect ratio of less than or equal to 1.5.

In some embodiments of the invention, the primary aerobic tank and the secondary aerobic tank are in a gallery type tank shape, and the length and the width of the primary aerobic tank and the secondary aerobic tank are both larger than those of the primary anaerobic tank, the primary anoxic tank, the secondary mobile tank and the secondary anoxic tank.

In some embodiments of the invention, the agitator is a vertical loop agitator.

In some embodiments of the invention, the primary aerobic tank and the secondary aerobic tank are separated from the primary return well and the secondary return well by partition walls, and a first wall-penetrating pump and a second wall-penetrating pump are respectively arranged on the two partition walls in a penetrating manner.

The embodiment of the invention also provides a treatment process of the two-stage A/O activated sludge process sewage treatment system, wherein the first-stage treatment system and the second-stage treatment system are switched into a parallel mode or a series mode according to the change of the water inlet quality standard or the water outlet quality standard of sewage;

when the water quality of inlet water or the water quality of outlet water is lower than a preset standard, switching the primary treatment system and the secondary treatment system into a parallel mode, adjusting the dissolved oxygen in the secondary mobile tank into an anaerobic tank, and discharging sewage through a water outlet channel after anaerobic, anoxic and aerobic and reflux process treatment is sequentially carried out in the primary treatment system and the secondary treatment system respectively;

when the water quality of the inlet water or the water quality of the outlet water is higher than a preset standard, the primary treatment system and the secondary treatment system are switched to be in a series connection mode, the dissolved oxygen in the secondary mobile tank is adjusted to be an anoxic tank, and sewage is discharged through the outlet channel after being sequentially treated by the anaerobic, anoxic, aerobic, anoxic and aerobic processes and the backflow processes of the primary treatment system and the secondary treatment system.

In some embodiments of the present invention, when the water quality of the inlet water or the water quality of the outlet water is lower than a preset standard, the first-stage treatment system and the second-stage treatment system are switched to a parallel mode, the dissolved oxygen in the second-stage mobile tank is adjusted to be an anaerobic tank, and the sewage is discharged through the outlet channel after being sequentially subjected to anaerobic, anoxic and aerobic treatment and reflux treatment in the first-stage treatment system and the second-stage treatment system, respectively, the method includes:

when the inlet water concentration is lower than a preset standard, closing the series inlet point gate, opening the outlet channel weir gate, and adjusting the dissolved oxygen in the secondary mobile tank to be an anaerobic tank so as to switch the primary treatment system and the secondary treatment system to be in a parallel mode;

sewage enters a primary anaerobic tank and a secondary mobile tank from a water inlet channel according to a preset proportion, the sewage treated by the primary anaerobic tank is treated by a primary anoxic tank and a primary aerobic tank respectively and then flows out through a water outlet channel, and part of the sewage flows back into the primary anoxic tank through a primary return well for treatment; and the sewage treated by the secondary maneuvering tank flows out through the water outlet channel after being treated by the secondary anoxic tank and the secondary aerobic tank respectively, and part of the sewage flows back into the secondary anoxic tank for treatment through the secondary return well.

In some embodiments of the present invention, the step of switching the primary treatment system and the secondary treatment system to a series mode when the quality of the inlet water or the water quality standard is higher than a preset standard, adjusting the dissolved oxygen in the secondary mobile tank to an anoxic tank, and discharging the sewage through the outlet channel after the sewage is sequentially treated by the anaerobic, anoxic, aerobic, anoxic and aerobic processes and the backflow processes of the primary treatment system and the secondary treatment system comprises:

when the effluent concentration or the total nitrogen discharge standard is higher than a preset standard, opening the series connection water inlet point gate, closing the water outlet channel weir gate and the first wall-penetrating pump, and adjusting the dissolved oxygen in the secondary mobile tank to be an anoxic tank so as to switch the primary treatment system and the secondary treatment system to be in a series connection mode;

sewage enters a primary anaerobic tank and a secondary mobile tank from a water inlet channel according to a preset proportion, the sewage treated by the primary anaerobic tank is treated by a primary anoxic tank and a primary aerobic tank respectively, then flows into the secondary mobile tank through a water outlet channel for treatment, is treated by the secondary anoxic tank and the secondary aerobic tank, flows out through the water outlet channel, and partially flows back into the secondary mobile tank for treatment through a secondary return well; and sewage entering the secondary mobile pool is treated by the secondary mobile pool, the secondary anoxic pool and the secondary aerobic pool respectively, discharged through the water outlet channel, and part of sewage flows back to the secondary mobile pool through the secondary return well for treatment.

Compared with the prior art, the embodiment of the invention has at least the following advantages or beneficial effects:

the invention relates to a device for treating sewage, which comprises a primary treatment system and a secondary treatment system which are arranged in parallel, wherein the primary treatment system comprises a primary anaerobic tank, a primary anoxic tank, a primary aerobic tank and a primary internal return well which are sequentially communicated, the primary anaerobic tank is externally connected with a primary sludge return pipe, the secondary treatment system comprises a secondary maneuvering tank, a secondary anoxic tank, a secondary aerobic tank and a secondary return well which are sequentially communicated, and the secondary maneuvering tank is externally connected with a secondary sludge return pipe; stirrers are arranged in the primary anaerobic tank, the primary anoxic tank, the secondary mobile tank and the secondary anoxic tank; a water inlet channel is arranged between the primary treatment system and the secondary treatment system in a penetrating manner, two water outlets of the water inlet channel are respectively communicated with the primary anaerobic tank and the secondary mobile tank through a first gate and a second gate, and a water inlet of the water inlet channel is connected with a water inlet pipe; the outer sides of the primary treatment system and the secondary treatment system are provided with water outlet channels, the water outlets of the primary aerobic pool and the secondary aerobic pool are communicated with the water outlet channels through a first water outlet weir and a second water outlet weir respectively, and the water outlet of the water outlet channelThe water outlet channel is communicated with the secondary mobile pool through a series water inlet point gate, a water outlet channel weir gate is further arranged in the water outlet channel, and the water outlet channel weir gate separates the series water inlet point gate from the second water outlet weir; the below of inlet channel is equipped with in one-level backward flow canal and second grade backward flow canal, one-level good oxygen pond with second grade good oxygen pond respectively with one-level backward flow well with the entry intercommunication of second grade backward flow well, one-level backward flow well with the export of second grade backward flow well respectively through first backward flow point and second backward flow point with in the one-level backward flow canal with the entry intercommunication of backward flow canal in the second grade, the export of one-level backward flow canal with one-level oxygen deficiency pond intercommunication, the export of second grade backward flow canal respectively with the second grade motor-driven pond with second grade oxygen deficiency pond intercommunication. The two-stage A/O treatment system can realize a two-stage A/O series connection mode or A by controlling a weir gate and a gate in a biochemical pool according to different water inlet amount, water quality or water outlet standards ² The switching of the/O parallel mode brings certain energy conservation and great convenience to the operation of a sewage plant; meanwhile, under an A/O series mode, sewage respectively enters a primary treatment system and a secondary treatment system in a step-by-step water inlet mode according to a certain proportion, namely the secondary A/O treatment system treats the effluent of the primary A/O system and also receives raw water of a part of proportion of sewage, so that a carbon source is provided for the denitrification reaction of a secondary anoxic tank, and the defect that a large amount of carbon source needs to be added in a post anoxic zone in a Bardenphos process is effectively overcome; in addition, when a certain unit device in the biochemical pool needs to be overhauled, the operation mode of the biochemical pool can be adjusted to be A ² The mode of the/O parallel connection is adopted, a water inlet point gate on the water inlet channel is controlled, serial water inlet is suspended for maintenance, and other serial water inlet can be normally treated, so that convenience is brought to operation.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings needed to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

FIG. 1 shows a conventional scheme A in the prior art ² A schematic structure diagram of the/O system;

FIG. 2 is a schematic structural diagram of a two-stage A/O activated sludge process sewage treatment system according to an embodiment of the present invention;

FIG. 3 is a flow chart showing the steps of a two-stage A/O activated sludge process for wastewater treatment according to an embodiment of the present invention.

Reference numerals: 100. a primary processing system; 110. a primary anaerobic tank; 111. a first gate; 120. a first-stage anoxic tank; 130. a primary aerobic tank; 131. a first effluent weir; 140. a primary internal return well; 141. a first through-wall pump; 142. a first reflux point; 200. a secondary processing system; 210. a secondary mobile pool; 211. a second gate; 212. a water inlet point gate is connected in series; 220. a secondary anoxic tank; 230. a secondary aerobic tank; 231. a second effluent weir; 240. a secondary return well; 241. a second through-wall pump; 242. a second reflow point; 300. a stirrer; 400. a water inlet channel; 500. a water inlet pipe; 600. a water outlet channel; 610. a water outlet channel weir gate; 700. a water outlet pipe; 800. a primary sludge return pipe.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, 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 some, but not all, embodiments of the present invention. The components of embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations.

Thus, the following detailed description of the embodiments of the present invention, presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. 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 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, it need not be further defined or explained in subsequent figures.

In the description of the embodiments of the present invention, it should be noted that, if the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings or the orientations or positional relationships that the products of the present invention are usually placed in when used, the orientations or positional relationships are only used for convenience of describing the present invention and simplifying the description, but the terms do not indicate or imply that the devices or elements indicated must have specific orientations, be constructed in specific orientations, and operate, and therefore, should not be construed as limiting the present invention.

Furthermore, the terms "horizontal", "vertical", "overhang" and the like do not require that the components be absolutely horizontal or overhang, but may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the embodiments of the present invention, it should be further noted that unless otherwise explicitly stated or limited, the terms "disposed," "mounted," "connected," and "connected" should be interpreted broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

Examples

Referring to fig. 1-2, fig. 1 shows a conventional a in the prior art ² A schematic structure diagram of the/O system; FIG. 2 is a schematic structural diagram of a two-stage A/O activated sludge process sewage treatment system according to an embodiment of the present invention;

the embodiment of the invention provides a two-stage A/O activated sludge process sewage treatment system, which specifically comprises: the system comprises a primary treatment system 100 and a secondary treatment system 200 which are arranged in parallel, wherein the primary treatment system 100 comprises a primary anaerobic tank 110, a primary anoxic tank 120, a primary aerobic tank 130 and a primary internal return well 140 which are sequentially communicated, the primary anaerobic tank 110 is externally connected with a primary sludge return pipe 800, the secondary treatment system 200 comprises a secondary maneuvering tank 210, a secondary anoxic tank 220, a secondary aerobic tank 230 and a secondary return well 240 which are sequentially communicated, and the secondary maneuvering tank 210 is externally connected with a secondary sludge return pipe; stirrers 300 are arranged in the primary anaerobic tank 110, the primary anoxic tank 120, the secondary mobile tank 210 and the secondary anoxic tank 220;

a water inlet channel 400 is arranged between the primary treatment system 100 and the secondary treatment system 200 in a penetrating manner, two water outlets of the water inlet channel 400 are respectively communicated with the primary anaerobic tank 110 and the secondary mobile tank 210 through a first gate 111 and a second gate 211, and a water inlet of the water inlet channel 400 is connected with a water inlet pipe 500;

the outer sides of the primary treatment system 100 and the secondary treatment system 200 are provided with an outlet channel 600, the water outlets of the primary aerobic tank 130 and the secondary aerobic tank 230 are respectively communicated with the outlet channel 600 through a first outlet weir 131 and a second outlet weir 231, the water outlet of the outlet channel 600 is connected with a water outlet pipe 700, the outlet channel 600 is communicated with the secondary mobile tank 210 through a series-connection inlet point gate 212, an outlet channel weir door 610 is further arranged in the outlet channel 600, and the outlet channel weir door 610 separates the series-connection inlet point gate 212 from the second outlet weir 231;

a first-stage internal reflux channel and a second-stage internal reflux channel are arranged below the water inlet channel 400, the first-stage aerobic tank 130 and the second-stage aerobic tank 230 are respectively communicated with inlets of the first-stage reflux well and the second-stage reflux well 240, outlets of the first-stage reflux well and the second-stage reflux well 240 are respectively communicated with inlets of the first-stage internal reflux channel and the second-stage internal reflux channel through a first reflux point and a second reflux point, an outlet of the first-stage reflux channel is communicated with the first-stage anoxic tank 120, and an outlet of the second-stage reflux channel is respectively communicated with the second-stage motorized tank 210 and the second-stage anoxic tank 220.

Next, a two-stage A/O activated sludge process sewage treatment system in the present exemplary embodiment will be further described.

In an implementation manner of this embodiment, the primary treatment system 100 includes a primary anaerobic tank 110, a primary anoxic tank 120, a primary aerobic tank 130, and a primary internal recycle well 140, which are sequentially connected, the primary anaerobic tank 110 is externally connected with a primary sludge recycle pipe 800, the secondary treatment system 200 includes a secondary mobile tank 210, a secondary anoxic tank 220, a secondary aerobic tank 230, and a secondary recycle well 240, which are sequentially connected, and the secondary mobile tank 210 is externally connected with a secondary sludge recycle pipe; in the present embodiment, preferably, there are three primary anoxic tanks 120 and three secondary anoxic tanks 220, where the primary anoxic tank 110 and the three primary anoxic tanks 120 are arranged in parallel in pairs, and the secondary mobile tank 210 and the three secondary anoxic tanks 220 are arranged in parallel in pairs; the first-stage anaerobic tank 110, the first-stage anoxic tank 120, the second-stage mobile tank 210 and the second-stage anoxic tank 220 are internally provided with stirrers 300.

A water inlet channel 400 is arranged between the primary treatment system 100 and the secondary treatment system 200 in a penetrating manner, the water inlet channel 400, a first internal backflow channel and a second internal backflow channel are transversely arranged between the primary anaerobic tank 110 and the three primary anoxic tank 120 which are arranged in parallel in a penetrating manner, and the secondary mobile tank 210 and the three secondary anoxic tank 220 in a penetrating manner, two water outlets of the water inlet channel 400 are respectively communicated with the primary anaerobic tank 110 and the secondary mobile tank 210 through a first gate 111 and a second gate 211, a water inlet pipe 500 is connected with a water inlet port 400, namely, sewage pretreated by a sewage plant flows into the water inlet channel 400 from the water inlet pipe 500 and then respectively enters the primary anaerobic tank 110 and the secondary mobile tank 210 through two water outlets of the water inlet channel 400, wherein the first gate 111 and the second gate 211 are used for controlling the opening and closing of the two water inlets;

the outer sides of the primary treatment system 100 and the secondary treatment system 200 are provided with an outlet channel 600, the water outlets of the primary aerobic tank 130 and the secondary aerobic tank 230 are respectively communicated with the outlet channel 600 through a first outlet weir 131 and a second outlet weir 231, the water outlet of the outlet channel 600 is connected with a water outlet pipe 700, that is, the sewage treated by the aerobic tanks of the two treatment systems can respectively flow out from the water outlet pipe 700 through the outlet channel 600, wherein the first outlet weir 131 and the second outlet weir 231 are used for controlling whether the two aerobic tanks are respectively communicated with the outlet channel 600; the outlet channel 600 is communicated with the secondary mobile pool 210 through the serial inlet point gate 212, an outlet channel weir gate 610 is further arranged in the outlet channel 600, the outlet channel weir gate 610 separates the serial inlet point gate 212 from the second outlet weir 231, when the primary treatment system 100 and the secondary treatment system 200 are connected in series, the serial inlet point gate 212 is opened to communicate the outlet channel 600 with the secondary mobile pool 210, and the outlet channel weir gate 610 is closed, so that the sewage of the primary treatment system 100 does not flow out of the outlet channel 600, but only flows into the secondary mobile pool 210 of the secondary treatment system 200;

a first-stage internal reflux channel and a second-stage internal reflux channel are arranged below the water inlet channel 400, the first-stage aerobic tank 130 and the second-stage aerobic tank 230 are respectively communicated with inlets of a first-stage reflux well and a second-stage reflux well 240, outlets of the first-stage reflux well and the second-stage reflux well 240 are respectively communicated with inlets of the first-stage internal reflux channel and the second-stage internal reflux channel through a first reflux point and a second reflux point, an outlet of the first-stage reflux channel is communicated with the first-stage anoxic tank 120, and an outlet of the second-stage reflux channel is respectively communicated with the second-stage motorized tank 210 and the second-stage anoxic tank 220, namely, after sewage of two treatment systems is treated by the aerobic tanks, mixed liquid flows into the water outlet channel 600 to be discharged, wherein the mixed liquid can realize circulation in the system, flows into the reflux channels through the reflux wells, and flows into the anoxic tanks again to be treated. The primary aerobic tank 130 and the secondary aerobic tank 230 are separated from the primary return well and the secondary return well 240 by partition walls, and a first wall-through pump 141 and a second wall-through pump 241 are respectively arranged on the two partition walls in a penetrating manner. Based on the internal reflux well and the tail end of the aerobic tank are connected through a partition wall, the internal reflux wall-penetrating pump is arranged on the partition wall, the internal reflux of the mixed liquid adopts a channel form, and the wall-penetrating pump saves a part of pipelines compared with the traditional submersible sewage pump.

It should be noted that the two-stage A/O system of the invention can flexibly change the operation mode of the whole biochemical pool by changing the sewage entry point and controlling the internal reflux, and the biochemical pool can realize the two-stage A/O series connection and the A/O series connection under the condition of the same retention time through the control of the weir gate and the gate according to the change of the inlet water quality or the different requirements of the outlet water standard ² The switching of the operation mode of the/O parallel connection brings convenience to the operation of the sewage plant, and the secondary mobile tank 210 is used as the primary treatment system 100 and the secondary treatment system 200 series-parallel switching of the change medium when the system is at "A ² In the/O parallel mode (i.e., the two systems are connected in parallel in an anaerobic-anoxic-aerobic series), the secondary mobile tank 210 serves as an anaerobic tank to ensure the dephosphorization efficiency of each series when connected in parallel, and at the moment, the two wall-penetrating pumps pump the nitrification liquid at the tail end of the aerobic tank of each series to the anoxic tank of the current series through the internal reflux channel to ensure the total nitrogen removal rate; when the system is in a 'two-stage A/O series connection' mode, the first grid in the first-stage treatment system 100 is used as an anaerobic tank to provide a phosphorus release environment for phosphorus accumulating bacteria, meanwhile, the first-stage internal reflux is stopped, the second-stage internal reflux flows back to the mobile tank through a wall-penetrating pump from the tail end of the second-stage aerobic tank 230, partial dissolved oxygen is brought into the mobile tank by the internal reflux of the aerobic zone to cause the mobile tank to be changed from the anaerobic environment to an anoxic environment, and at the moment, the second-stage mobile tank 210 is used as an anoxic tank. The phosphorus accumulating bacteria in the sewage in the anaerobic stage release phosphorus in the anaerobic environment to enable the phosphorus accumulating bacteria to reach a starvation state, the phosphorus accumulating bacteria absorb a large amount of phosphorus in the sewage in the aerobic stage, the denitrifying bacteria reproduce faster in the anoxic environment in the anoxic stage to become dominant bacteria, nitrite and nitrate in the sewage, namely nitrate nitrogen, are denitrifying to be nitrogen gas to be released, organic carbon in the sewage and ammonia nitrogen are degraded in the aerobic stage, the ammonia nitrogen is oxidized to be the nitrate nitrogen, and microorganisms such as the phosphorus accumulating bacteria, the nitrifying bacteria and the denitrifying bacteria in the sewage in the three stages play respective roles in different environments to realize nitrogen and phosphorus removal.

In one specific implementation, the operational mode is flexibly adjusted according to the water quality change of the inlet water or when the water quality standard of the outlet water is increased, "A ² The operation mode of/O parallel connection is suitable for the condition that the earlier-stage effluent standard of some sewage plants is low and is not improved temporarily, the operation mode of two-stage A/O series connection is suitable for the condition that the effluent standard of sewage plants is high after the later-stage upgrading and transformation (especially for the improvement of TN emission standard), the process of two-stage A/O series connection is formed by connecting two anoxic/aerobic sections in series, when the system of the invention operates according to the mode of two-stage A/O series connection, the secondary mobile pool 210 serves as an anoxic pool, sewage enters from the water inlet pipe 500 to the water inlet channel 400, and the proportion of each-stage water inlet is controlled through the opening and closing degree of the first gate 111 and the second gate 211 at the water inlet pointRespectively enters each stage of system for treatment, sewage simultaneously enters the primary anaerobic tank 110 and the secondary mobile tank 210 according to a certain proportion, the serial connection water inlet point gate 212 keeps an open state, the water outlet channel weir gate 610 is closed, and the first wall-penetrating pump 141 in the first backflow well keeps closed. At the moment, the first-stage A/O of the internal reflux system of the whole biochemical pond is closed, the second-stage A/O is opened, the second wall-penetrating pump 241 in the second reflux well is opened, the mixed liquid flows back to the secondary mobile pond 210 through the internal reflux channel from the reflux well, the effluent of the primary aerobic pond 130 flows into the secondary mobile pond 210 through the effluent channel 600 to bring a certain amount of dissolved oxygen, the secondary mobile pond 210 is used as an anoxic pond, the effluent of the second-stage A/O system flows into the effluent channel 600 through the second effluent weir 231, and finally flows out of the system through the effluent pipe 700, and the return sludge of the secondary sedimentation pond flows back to the primary anaerobic pond 110 of the system through the primary sludge return pipe 800; when the system is marked with' A ² When the two-stage mobile pool 210 operates in a mode of O parallel connection, sewage enters the first gate 111 and the second gate 211 of the water inlet points in equal proportion, the gate 212 of the water inlet points in series connection is closed, the weir gate 610 of the water outlet channel is opened, and two groups A of the two gates are used as anaerobic pools ² Effluent of the/O system enters the effluent channel 600 from the first effluent weir 131 and the second effluent weir 231 respectively and finally flows into the effluent pipe 700, meanwhile, two groups of internal reflux systems in the biochemical pond start to operate, an internal reflux wall-through pump in the reflux well enables nitrified liquid at the tail end of each series of aerobic ponds to respectively reflux to the series of anoxic ponds through the internal reflux channel below the water inlet channel 400, and the first internal reflux channel and the second internal reflux channel are separated in the first-stage system and the second-stage system and are not communicated with each other; when in parallel connection, the return sludge respectively returns to the first-stage anaerobic tank 110 of the system through the first-stage sludge return pipe 800 and returns to the second-stage mobile tank 210 of the system through the second-stage sludge return pipe.

In one embodiment of this embodiment, the primary anaerobic tank 110, the primary anoxic tank 120, the secondary mobile tank 210 and the secondary anoxic tank 220 are rectangular tanks, and have an aspect ratio of 1.5 or less; the above-mentioned one-level aerobic tank 130 and second grade aerobic tank 230 are corridor type pool types, and its length and width all are greater than the length and width of one-level anaerobism pond 110, one-level oxygen deficiency pond 120, second grade mobile pool 210 and second grade oxygen deficiency pond 220, and the setting up of a plurality of rectangle ponds makes the agitator 300 dismouting of being convenient for, and corridor type's aerobic tank can avoid the short-term flow, maintain good flow state and help in the pond sewage and microorganism to mix.

As an example, when the aspect ratio is equal to 1, that is, when the tank is a square tank, the stirrer 300 is a vertical circulation stirrer 300, and the vertical circulation stirrer 300 is adopted, the stirring effect is better for the square tank with a small aspect ratio, the stirring dead angle is eliminated, the space distribution of the activated sludge in the tank is uniform, and the sedimentation of the activated sludge in the anaerobic and anoxic tank is effectively reduced; when the tank is a rectangular tank other than a square tank, other agitators may be used.

The 'two-stage A/O' system of the invention utilizes the special internal pool type layout structure design, especially the arrangement form of the water inlet channel 400, the water outlet channel 600 and the internal backflow channel, the arrangement of the water inlet channel 400 is positioned in the middle of the whole biochemical system, runs through each stage of the whole system, and can set water inlet points in the anaerobic pool of the first stage and the anoxic pool of the second stage, the water outlet channel 600 is communicated with each stage of aerobic section and the anoxic section outside the second stage, the weir gate on the water outlet channel 600 is closed when in series connection, at this time, the water outlet channel 600 is used as the water outlet channel 600 of the previous stage and is also used as the water inlet channel 400 of the next stage system; when the parallel operation is performed, the weir gate on the water outlet channel 600 is opened, and the water inlet of the anoxic section on the water outlet channel 600 is closed, at this time, the water outlet channel 600 is a main water outlet channel for collecting each series A ² The water outlet of the/O channel and the arrangement of the two channels meet the conversion of series connection and parallel connection of the system functionally, and the spatial layout is neat and beautiful. The internal reflux channel is positioned under the water inlet channel 400 and is respectively communicated with the reflux well and the anoxic tank of the first-stage system, the reflux well and the motorized tank of the second-stage system and the first grid of the second-stage anoxic zone to form the characteristic that each stage of anoxic/aerobic sections can be connected in series and in parallel, and the operation mode of the biochemical tank can be controlled by the gate and the weir gate on the 600 channels of the water inlet and outlet channel ² The mode of the/O parallel connection and the mode of the two-stage A/O series connection are switched, so that the problem that the sewage plant cannot flexibly deal with different water quantities and water qualities in different periods or the later period of upgrading (especially the improvement of total nitrogen index) is solved, namely the sewage plant can not increase the investment of additionally reforming a biochemical pool beforeThe problem is solved, the sewage is subjected to two-stage anoxic/aerobic treatment in the biochemical tank, the removal rate of pollutants is greatly improved, the investment of modification is saved, and good conditions are provided for the operation of sewage plants; in addition, when a certain unit device in the biochemical pool needs to be overhauled, the operation mode of the biochemical pool can be adjusted to be A ² The mode of the/O parallel connection is adopted, the water inlet point gate on the water inlet channel 400 is controlled, the serial water inlet is temporarily stopped to be maintained, and other serial water inlet can be normally treated, so that convenience is brought to operation.

If the biochemical pool of a sewage treatment plant adopts the arrangement form of the invention, the recent scale of the sewage treatment plant is smaller, the effluent standard is the first-class A standard, and the requirement on the discharge of nitrogen and phosphorus is not high, then the A standard can be adopted ² The operation mode of the/O parallel connection enables the total nitrogen removal rate to be about 60 percent, and the standard discharge can be achieved by matching with the subsequent advanced treatment. The sewage plant can only operate one series when the initial water amount of the sewage plant is small, the number of the series of operation can be increased when the recent water amount gradually rises, and the whole series of operation is performed when the sewage plant is not in the initial water amount, so that the early operation cost of the sewage plant is saved. When the effluent quality of the sewage plant is improved to the III-class standard on the ground surface in the later period, the A of the biochemical pool can be regulated ² the/O parallel mode is switched to a two-stage A/O series mode, the two anoxic/aerobic sections are connected in parallel, the denitrification effect of the sewage is improved, the total nitrogen removal rate is about 70%, meanwhile, the sewage enters from the anoxic zones at all stages according to a certain design proportion, the carbon source in the systems at all stages is ensured to be sufficient, the sewage treatment effect is improved under the condition that the hydraulic retention time is kept to be the same, and the operation mode facing different water quality standards of inlet and outlet water can be provided for sewage plants.

Referring to FIG. 3, FIG. 3 is a flow chart illustrating steps of a two-stage A/O activated sludge process for wastewater treatment according to an embodiment of the present invention;

the embodiment of the invention provides a two-stage A/O activated sludge process for sewage treatment, which specifically comprises the following steps:

s110, switching the primary treatment system 100 and the secondary treatment system 200 into a parallel mode or a series mode according to the change of the inlet water quality standard or the outlet water quality standard of the sewage;

s120, when the water quality of inlet water or the water quality of outlet water is lower than a preset standard, switching the primary treatment system 100 and the secondary treatment system 200 to be in a parallel mode, adjusting the dissolved oxygen in the secondary mobile tank 210 to be an anaerobic tank, and discharging the sewage through an outlet channel 600 after the sewage is respectively subjected to anaerobic, anoxic and aerobic and reflux process treatments in the primary treatment system 100 and the secondary treatment system 200 in sequence;

s130, when the quality of the inlet water or the water quality standard is higher than a preset standard, the primary treatment system 100 and the secondary treatment system 200 are switched to be in a series connection mode, the dissolved oxygen in the secondary mobile tank 210 is adjusted to be an anoxic tank, and the sewage is subjected to anaerobic, anoxic, aerobic, anoxic and aerobic treatment and reflux process treatment sequentially through the primary treatment system 100 and the secondary treatment system 200 and then is discharged through an outlet channel 600.

Next, a two-stage A/O activated sludge process for wastewater treatment in the present exemplary embodiment will be further described.

In an embodiment of the present invention, as described in step S120, "when the quality of the inlet water or the quality of the outlet water is lower than the predetermined standard, the primary treatment system 100 and the secondary treatment system 200 are switched to a parallel mode, the dissolved oxygen in the secondary mobile tank 210 is adjusted to be an anaerobic tank, and the sewage is discharged through the outlet channel 600 after the anaerobic, anoxic and aerobic and reflux processes are performed in the primary treatment system 100 and the secondary treatment system 200, respectively.

When the influent concentration is low and is lower than a preset level, the series-connected influent point gate 212 is closed, the effluent channel weir 610 is opened, and the dissolved oxygen in the secondary mobile tank 210 is adjusted to an anaerobic tank, so as to switch the primary treatment system 100 and the secondary treatment system 200 to a parallel mode, as described in the following steps.

As an example, sewage enters the primary anaerobic tank 110 and the secondary mobile tank 210 from the water inlet channel 400, the primary anaerobic tank 110 releases phosphorus in raw sewage, the sewage sequentially flows into the plurality of subsequent primary anoxic tanks 120 for denitrification, the sewage flows into the primary aerobic tank 130 for oxidative degradation of organic carbon and ammonia nitrogen, then the mixed liquid flows out through the water outlet channel 600, part of the mixed liquid can also circulate inside the system, and the mixed liquid flows back into the primary anoxic tank 120 through the primary return well to generate nitrogen gas through denitrification again for discharge; after the sewage in the secondary mobile tank 210 is subjected to denitrification in the secondary anoxic tank 220 and oxidative degradation in the secondary aerobic tank 230, the mixed liquor flows out through the water outlet channel 600, wherein the mixed liquor also circulates in the system and flows back into the secondary anoxic tank 220 through the secondary return well 240 to perform denitrification again to discharge nitrogen.

In an embodiment of the present invention, as described in step S130, "when the quality of the inlet water or the water quality standard is higher than the predetermined standard, the primary treatment system 100 and the secondary treatment system 200 are switched to be in a series connection mode, the dissolved oxygen in the secondary mobile tank 210 is adjusted to be an anoxic tank, and the sewage is discharged through the outlet channel 600 after being sequentially processed by the anaerobic, anoxic, aerobic, anoxic and aerobic processes and the backflow processes through the primary treatment system 100 and the secondary treatment system 200" as follows.

As described in the following steps, when the quality of the inlet water is poor, the concentration of the outlet water is high, or the total nitrogen discharge standard is increased and is higher than a preset standard, the serial inlet point gate 212 is opened, the outlet channel weir gate 610 and the first through-wall pump 141 are closed, and the dissolved oxygen in the secondary mobile pool 210 is adjusted to be an anoxic pool, so that the primary treatment system 100 and the secondary treatment system 200 are switched to be in a serial mode.

As an example, sewage enters the primary anaerobic tank 110 and the secondary mobile tank 210 from the water inlet channel 400, the sewage treated by the primary anaerobic tank 110 enters the secondary mobile tank 210 through the water outlet channel 600 after being treated by the primary anoxic tank 120 and the primary aerobic tank 130, the sewage flows out through the water outlet channel 600 after being treated by the secondary anoxic tank 220 and the secondary aerobic tank 230, the sewage flows out through the water outlet channel 600, namely, mixed liquid flowing out through the primary aerobic tank 130 enters the four secondary anoxic tanks 220 for denitrification, nitrate nitrogen coming from the primary aerobic tank 130 is denitrified, ammonia nitrogen and organic carbon in the sewage are oxidized by the secondary aerobic tank 230 and then discharged, part of the mixed liquid can be circulated in the system, and the mixed liquid flows back to the secondary mobile tank 210 through the secondary return well 240 for denitrification again; the sewage entering the secondary mobile pool 210 is treated by the secondary mobile pool 210, the secondary anoxic pool 220 and the secondary aerobic pool 230 respectively, and then discharged through the water outlet channel 600, and part of the mixed liquid is circulated in the system and flows back to the secondary mobile pool 210 through the secondary return well 240 for treatment. It should be noted that, when connected in series, the secondary mobile tank 210 receives a portion of raw water of sewage, and mainly provides a carbon source for the denitrification reaction in the secondary anoxic zone. In the series mode, the sewage entering the primary anaerobic tank 110 and the secondary mobile tank 210 is discharged in proportion.

The two-stage A/O activated sludge process sewage treatment system and the process provided by the embodiment of the invention provide a design idea of a biochemical pool for the condition that the effluent cannot reach the standard (especially total nitrogen index) caused by water quality fluctuation encountered in daily operation of a sewage plant or the improvement of the total nitrogen emission requirement when the sewage plant carries out standard improvement and transformation in the future, provide a two-stage A/O system capable of being operated in series and in parallel, and adopt a special arrangement form of pool types in the biochemical pool to connect two A/O systems in parallel ² the/O series are integrated in one system, and are converted into a series multistage A/O process by controlling a weir gate and a gate when the water quality concentration of inlet water is high or the water quality standard of outlet water is improved (especially total nitrogen), so that two series of A connected in parallel are realized ² The free switching between the/O operation mode and the two-stage A/O operation mode in series brings great convenience to the operation of the sewage plant, and when the water inflow of the sewage plant is small in the early stage of construction, the parallel A operation can be adjusted ² The serial number of the/O system saves certain energy consumption and has extremely high use value.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to 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 two-stage A/O activated sludge process sewage treatment system is characterized by comprising a primary treatment system and a secondary treatment system which are arranged in parallel, wherein the primary treatment system comprises a primary anaerobic tank, a primary anoxic tank, a primary aerobic tank and a primary internal return well which are sequentially communicated, the primary anaerobic tank is externally connected with a primary sludge return pipe, the secondary treatment system comprises a secondary maneuvering tank, a secondary anoxic tank, a secondary aerobic tank and a secondary return well which are sequentially communicated, and the secondary maneuvering tank is externally connected with a secondary sludge return pipe; stirrers are arranged in the primary anaerobic tank, the primary anoxic tank, the secondary mobile tank and the secondary anoxic tank;

the outer sides of the primary treatment system and the secondary treatment system are provided with water outlet channels, the water outlets of the primary aerobic tank and the secondary aerobic tank are respectively communicated with the water outlet channels through a first water outlet weir and a second water outlet weir, the water outlet of the water outlet channels are connected with a water outlet pipe, the water outlet channels are communicated with the secondary mobile tank through a series connection water inlet point gate, water outlet channel weir doors are further arranged in the water outlet channels, and the series connection water inlet point gate and the second water outlet weir are separated by the water outlet channel weir doors;

2. The two-stage a/O activated sludge process wastewater treatment system of claim 1 wherein at least one of said primary anoxic tank and said secondary anoxic tank is provided.

3. The two-stage a/O activated sludge process wastewater treatment system of claim 1 wherein there are three of said primary anoxic tanks and three of said secondary anoxic tanks, respectively.

4. The two-stage a/O activated sludge process wastewater treatment system of claim 1 wherein said primary anaerobic tank, said primary anoxic tank, said secondary mobile tank and said secondary anoxic tank are rectangular tank shaped with an aspect ratio of 1.5 or less.

5. The two-stage a/O activated sludge process wastewater treatment system of claim 1 wherein said primary aerobic tank and said secondary aerobic tank are of a gallery type tank configuration having a length and width greater than the length and width of said primary anaerobic tank, said primary anoxic tank, said secondary mobile tank, and said secondary anoxic tank.

6. The two-stage A/O activated sludge process wastewater treatment system of claim 4 wherein said agitator is a vertical loop agitator.

7. The two-stage a/O activated sludge process wastewater treatment system of claim 6 wherein said primary aerobic tank and said secondary aerobic tank are separated from said primary recirculation well and said secondary recirculation well by a partition wall, and wherein a first wall-penetrating pump and a second wall-penetrating pump are respectively disposed through said two partition walls.

8. A process according to any one of claims 1 to 7 for treating a two stage a/O activated sludge process wastewater treatment system, comprising the steps of:

switching the primary treatment system and the secondary treatment system into a parallel mode or a series mode according to the change of the inlet water quality standard or the outlet water quality standard of the sewage;

9. The two-stage a/O activated sludge process of claim 8 wherein when the quality of the influent water or effluent water is lower than a predetermined standard, switching the primary treatment system and the secondary treatment system to a parallel mode, adjusting the dissolved oxygen in the secondary mobile tank to an anaerobic tank, and discharging the wastewater through an effluent channel after sequentially performing anaerobic, anoxic and aerobic and reflux processes in the primary treatment system and the secondary treatment system, respectively, comprises:

sewage enters a primary anaerobic tank and a secondary mobile tank from a water inlet channel according to a preset proportion, the sewage treated by the primary anaerobic tank is treated by a primary anoxic tank and a primary aerobic tank respectively, then flows out through a water outlet channel, and part of the sewage flows back to the primary anoxic tank through a primary return well for treatment; and the sewage treated by the secondary maneuvering tank flows out through the water outlet channel after being treated by the secondary anoxic tank and the secondary aerobic tank respectively, and part of the sewage flows back into the secondary anoxic tank for treatment through the secondary return well.

10. The two-stage a/O activated sludge process of claim 8, wherein when the quality of the influent water or the effluent water is higher than a predetermined standard, the first stage treatment system and the second stage treatment system are switched to a series mode, the dissolved oxygen in the second stage mobile tank is adjusted to be an anoxic tank, and the sewage is treated by anaerobic, anoxic, aerobic, anoxic and aerobic processes and a backflow process in the first stage treatment system and the second stage treatment system in sequence and then discharged through the effluent channel, comprising: