CN111499005A

CN111499005A - High-efficiency nitrogen and phosphorus removal domestic sewage treatment equipment for enriching denitrifying phosphorus accumulating bacteria

Info

Publication number: CN111499005A
Application number: CN202010322152.9A
Authority: CN
Inventors: 段远晗; 邵洪; 刘长林
Original assignee: Jiangsu Bol Qingyuan Environmental Technology Co ltd
Current assignee: Jiangsu Bol Qingyuan Environmental Technology Co ltd
Priority date: 2020-04-22
Filing date: 2020-04-22
Publication date: 2020-08-07

Abstract

The invention discloses a high-efficiency denitrification and dephosphorization domestic sewage treatment device for enriching denitrification phosphorus-accumulating bacteria, which comprises a pool body, an anaerobic pool, an adsorption pool, an anoxic pool, a facultative pool, an aerobic pool and a sedimentation pool; the tank body is integrally assembled by rectangular carbon steel open type multi-channel integration; the left side is provided with a sedimentation tank, the right side is provided with a facultative tank, and the middle is provided with an anaerobic tank, an anoxic tank, an aerobic tank and an adsorption tank; a return channel, a water outlet channel, an air inlet pipe, an water inlet pipe, a water outlet pipe and a residual sludge pipe are arranged at the periphery of the sludge tank; by controlling the process and the operating conditions, the DPB in the system dominates, the synchronous nitrogen and phosphorus removal can be realized under the condition of low carbon source, and the 'one carbon dual-purpose' is realized; the invention can induce DPB to become dominant flora under the condition of low C/N to play a role in denitrifying phosphorus removal, has good effect of nitrogen and phosphorus removal, effectively prevents sludge bulking, and meets the requirements of stable and efficient complete equipment for nitrogen and phosphorus removal of domestic sewage.

Description

High-efficiency nitrogen and phosphorus removal domestic sewage treatment equipment for enriching denitrifying phosphorus accumulating bacteria

Technical Field

The invention relates to the technical field of domestic sewage treatment equipment, in particular to high-efficiency nitrogen and phosphorus removal domestic sewage treatment equipment for enriching denitrifying phosphorus-accumulating bacteria.

Background

With the scientific and technological progress and the development of social economy, the standard of urban domestic sewage treatment is continuously improved; a large amount of nitrogen and phosphorus wastewater in the sewage is directly discharged into a water body without proper treatment, so that the water body environment is seriously polluted, and the human health is seriously harmed. The problem of nitrogen and phosphorus removal in domestic sewage causes difficulty in the standard-reaching discharge of town sewage. The traditional biological nitrogen and phosphorus removal method plays a certain role in sewage treatment, but still has a plurality of defects. If competition of phosphorus-accumulating bacteria and denitrifying bacteria for carbon sources always exists, the sludge ages of nitrifying bacteria, denitrifying bacteria and phosphorus-accumulating bacteria are different, various bacteria are mixed together and are restricted with each other, and the system is difficult to achieve the optimal operation condition; under the condition of low C/N ratio, the aerobic biological phosphorus removal process increases power consumption and generates a large amount of excess sludge; the whole treatment process has longer flow, large floor area, high capital investment and the like.

With the continuous and intensive research on sewage treatment, several novel biological nitrogen and phosphorus removal processes have been developed and applied in recent years, mainly including: the novel processes comprise a synchronous nitrification and denitrification process, a short-cut nitrification and denitrification process, an anaerobic ammonia oxidation process, a completely autotrophic nitrogen removal process and a denitrification and phosphorus removal process, and have the advantages of reducing energy consumption, saving carbon sources, reducing sludge yield, occupying less land and the like. Particularly, the denitrifying phosphorus removal process enables two independent processes of phosphorus removal and denitrification to be simultaneously completed only in an anoxic environment under the participation of denitrifying phosphorus bacteria DPB (denitrifying phosphorus culturing bacteria), the combination of the processes of phosphorus absorption and denitrification not only saves the need of a carbon source, but also saves the energy required by aeration when the phosphorus absorption is completed in the anoxic environment, and the generated residual sludge amount is greatly reduced. Therefore, the denitrification dephosphorization technology has become one of the key points and hot spots in the research field of dephosphorization and denitrification of sewage at present.

In the prior art, the sewage treatment process can not take nitrogen removal and phosphorus removal into consideration, and the process needs to be improved; the disadvantages of the prior art are represented by: 1. the integration of the equipment is not high enough; 2The problem of the contradiction of sludge age is difficult to solve, namely the sludge age of autotrophic Nitrite Oxidizing Bacteria (NOB) is long, and the sludge age of DPB and phosphorus accumulating bacteria (PAOs) is short, so that the sludge can not simultaneously exert the maximum efficiency in the same system; 3. carbon source competition: DPB, PAOs and denitrifying bacteria in the sewage with low C/N ratio compete for a carbon source; 4. DO and NO carried in sludge recirculation₃ ^-Inhibit the anaerobic phosphorus release of DPB and PAOs.

Disclosure of Invention

In order to solve the technical problems, the invention provides high-efficiency denitrification and dephosphorization domestic sewage treatment equipment for enriching denitrifying phosphorus accumulating bacteria, aiming at the defects in the prior art, the equipment has the advantages of high research and development integration level, low consumption, high efficiency, easy operation and management, stable operation and capability of realizing the rapid enrichment of DPB; the enrichment configuration equipment is optimized, the high-efficiency enrichment of DPB is realized under the low C/N condition, and the requirements of the domestic sewage high-efficiency nitrogen and phosphorus removal complete equipment are met.

In order to achieve the purpose, the technical scheme of the invention is as follows: an efficient denitrification and dephosphorization domestic sewage treatment device for enriching denitrification phosphorus-accumulating bacteria, which is called denitrification and dephosphorization device for short; comprises a tank body, an anaerobic tank, an adsorption tank, an anoxic tank, a facultative tank, an aerobic tank and a sedimentation tank; the method is characterized in that:

the nitrogen and phosphorus removal equipment is of a rectangular carbon steel structure, and the tank body is integrally assembled by a plurality of open channels without top covers; the aspect ratio of the channel of the nitrogen and phosphorus removal equipment is 5: 1-10: 1, and the width-depth ratio is 1: 1-2: 1; a sedimentation tank is arranged on the left side of the tank body, a facultative tank is arranged on the right side of the tank body, an anaerobic tank and an anoxic tank are arranged in parallel on the lower middle part, and an aerobic tank is arranged in parallel on the upper middle part; an adsorption tank is arranged above the anaerobic tank; backflow channels are arranged on the left side and the periphery of the upper part of the inner side of the tank body; a water outlet channel is arranged on the right side of the inner side of the tank body; the upper part and the left side of the outer side of the tank body are respectively provided with two groups of air inlet pipes, and the lower part of the outer side of the tank body is respectively provided with a water inlet pipe, a water outlet pipe and a residual sludge pipe; an air ejector is arranged at the upper left corner in the tank body;

water holes are arranged among the anaerobic tank, the adsorption tank, the anoxic tank, the facultative tank, the aerobic tank and the sedimentation tank, and hydraulic power is applied to the anaerobic tank, the adsorption tank, the anoxic tank, the facultative tank, the aerobic tank and the sedimentation tankThe shape is plug flow type; the starting end of the anaerobic tank is provided with a water inlet pipe and a submersible plug flow stirrer, and the tail end of the anaerobic tank is provided with an oxidation-reduction potential meter (ORP meter); a submersible stirrer is arranged in the center of the adsorption tank, the submersible stirrer is provided with an upper group of blades and a lower group of blades, and a water passing hole arranged on one side of the adsorption tank, which is close to the sedimentation tank, is used as a sludge return hole; the starting end of the facultative tank is provided with a submersible plug flow stirrer, and the starting end of the facultative tank is communicated with the return channel of the mixed liquid in the aerobic tank through a water through hole; a pipeline leading to the bottom of the anoxic tank is arranged at the bottom of the backflow channel, an ORP (oxidation-reduction potential) instrument and a submersible backflow pump are arranged at the tail end of the backflow channel, and an outlet of the backflow pump is positioned at the starting end of the anaerobic tank and is provided with a flap valve; the facultative tank is respectively provided with two grids which are arranged in series front and back, the starting end of each grid is provided with a submersible plug flow stirrer, the bottom of each grid is provided with an aerator, and the tail end of the second grid of the facultative tank is provided with an ORP instrument and a dissolved oxygen instrument (DO instrument); the aerobic tank is divided into two grids which are arranged in parallel and in series, an aerator is arranged at the bottom of each grid, moving bed fillers are filled in the aerobic tank, a DO instrument and an air lifter are arranged at the tail end of a second grid of the aerobic tank, and mixed liquid in the aerobic tank flows to a return channel through the air lifter; a stainless steel mesh is arranged between the air lifting pusher and the aerobic tank and is used for preventing the moving bed filler from entering the area of the air lifting pusher; a channel gate is arranged on a return channel of the mixed liquid leading to the facultative tank and the anoxic tank and used for adjusting the return flow; the sedimentation tank adopts the form of outside long-edge water inlet and long-edge water outlet, a water distribution hole is arranged below a water inlet channel of the sedimentation tank, a hydraulic baffle is arranged below the water distribution hole, sludge in the sedimentation tank is discharged into a sludge return channel through a travelling sludge scraping and sucking machine, the returned sludge enters the adsorption tank through a sludge return hole on the adsorption tank, and residual sludge is discharged through a residual sludge pipe at the tail end of the channel; the whole process is controlled by three ORP instruments and two DO instruments to ensure the effluent NH₄ ⁺＜3mg/L，TN＜10mg/L， TP＜0.5mg/L。

The hydraulic retention time of the anaerobic pool, the adsorption pool, the anoxic pool, the facultative pool, the aerobic pool and the sedimentation pool is respectively 1.5h, 0.3h, 2h, 6h and 2h, the surface load of the sedimentation pool is 0.8m 3/square meter · h-1.2 m 3/square meter · h, the ORP control range of the anaerobic pool is-450 mV to-250 mV, the ORP control range of the anoxic pool is-150 mV to 0mV, the ORP control range of the facultative pool is-100 mV to 50mV, the DO control range of the facultative pool is less than 0.6 mg/L, and the DO control range of the aerobic pool is 1.5 mg/L to 2.5 mg/L.

The submerged stirrer in the adsorption tank adopts a low-speed stirrer, and the stirring speed is 40-60 r/min; the unit power of the submersible plug flow stirrer in the anaerobic tank, the anoxic tank and the facultative tank is 2W/m³4W/m3 (wastewater).

The anoxic tank flows back to the anaerobic tank, and the reflux ratio is 100%; the sludge in the sedimentation tank flows back to the adsorption tank, the reflux ratio is 50% -100%, the DPB is alternately enriched in anaerobic/anoxic volume through reflux, and NO is eliminated to the maximum extent through the mode that the mixed liquor in the anoxic tank flows back to the anaerobic tank₃ ^-And DO inhibition of DPB and PAOs.

The facultative tank adopts an intermittent aeration mode, the mixed liquor of the anoxic tank and the mixed liquor of the return flow of the aerobic tank enter the facultative tank together, DPB is induced to become dominant flora under the condition of low C/N ratio, the synchronous denitrification and dephosphorization operation is realized, and the facultative tank has the characteristic of one carbon and two purposes; and enhances the synchronous nitrification-denitrification (SND) of the facultative denitrifying bacteria under the low DO condition.

The control mode of the facultative tank aeration is that when water is discharged NH₄ ⁺When the concentration of the wastewater is less than or equal to 3 mg/L, aeration is started under the following three conditions that the DO of the aerobic pool ① is less than 1.5 mg/L, the ORP of the facultative pool ② is less than-100 mV, the OPR of the anoxic pool ③ is less than-150 mV, and NH in effluent₄ ⁺When the concentration is more than 3 mg/L, the facultative tank is aerated until water NH is discharged₄ ⁺Less than or equal to 3 mg/L, NH when yielding water₄ ⁺And when the concentration is less than or equal to 3 mg/L, the aeration is closed under the following two conditions that the DO of the facultative tank ① is more than 0.6 mg/L, and the ORP of the facultative tank ② is more than 50 mV.

A moving bed filler is arranged in the aerobic tank, nitrifying bacteria (NOB) with longer sludge age are fixed, and NH is strengthened₄ ⁺Removing effect, wherein the filling ratio of the filler is 20% -50%; what is needed isThe reflux of the mixed liquid in the aerobic tank adopts an air stripping pushing mode, so that the energy consumption is reduced, and simultaneously, the large reflux ratio is realized, and the reflux ratio range is 100-400%; the return flow of the mixed liquid in the aerobic tank is realized by controlling the air blower to increase or decrease the air quantity supplied to the air lifter through the frequency converter.

Controlling the reflux amount of the mixed liquid in the aerobic tank, namely when the OPR of the anoxic tank is less than-150 mV, properly increasing the reflux amount to the anoxic tank by increasing the opening of a channel gate; when the ORP of the facultative tank is less than-100 mV, properly increasing the reflux amount to the facultative tank by increasing the opening of a channel gate; when the OPR of the anoxic pond is more than 0mV, properly reducing the reflux amount to the anoxic pond by reducing the opening of the canal gate; when the ORP of the facultative tank is more than 50mV, the return flow to the facultative tank is properly reduced by reducing the opening degree of a channel gate.

The working principle of the invention is as follows:

domestic sewage firstly enters an anaerobic tank, phosphorus accumulating bacteria (PAOS) and DPB carry out anaerobic phosphorus release and the COD of the inlet water is utilized to synthesize poly- β hydroxybutyric acid (PHB), and the process is easy to be subjected to NO₃ ^-And DO, so as to reduce the anaerobic phosphorus release efficiency; therefore, the sludge is returned to the adsorption tank through the sedimentation tank and is fully mixed with the mixed liquid from the anaerobic tank, residual COD is adsorbed to prevent the sludge from expanding, and PHB is synthesized; DPB utilizes PHB as an electron donor, NO₃ ^-Endogenous denitrification as an electron acceptor, the process being continued in an anoxic tank, the NO at the end of which₃ ^-And DO content is almost zero, the anoxic mixed liquor flows back to the starting end of the anaerobic tank through a reflux pump, and a good 'suppressing' environment is created for the anaerobic phosphorus release of the DPB; the mixed liquor of the anoxic tank and the mixed liquor refluxed from the aerobic tank enter a facultative tank together, Synchronous Nitrification and Denitrification (SND) are realized under the condition of low DO, the nitrification and denitrification are respectively carried out in the aerobic tank and the facultative tank at respective maximum reaction rates, and simultaneously, the DPB carries out denitrification dephosphorization; little COD enters the aerobic tank, the NOB occupies the dominant position in the aerobic tank, and moving bed filler is added into the aerobic tank to fix the NOB with longer sludge age and strengthen the nitrification effect; simultaneously, DPB and PAOS carry out dephosphorization and sludge regeneration, and an aerobic pool is mixedThe combined liquid flows back to the facultative tank and the anoxic tank, and the purpose of the backflow anoxic tank is to assist the backflow sludge to supplement NO to the anoxic tank₃ ^-Satisfies the DPB utilization of NO₃ ^-The derivative is used as an electron acceptor to realize denitrification and induce the enrichment of DPB under the alternate anaerobic/anoxic condition. And (4) discharging water from the aerobic tank to a sedimentation tank, lifting the sludge to a sludge return channel through a travelling type sludge scraping and sucking machine, and then flowing into an adsorption tank.

Through the technical scheme, the technical scheme of the invention has the beneficial effects that: the nitrogen and phosphorus removal equipment has high integrated degree and good nitrogen and phosphorus removal effect under the condition of low C/N; the nitrogen and phosphorus removal equipment ensures that DPB in the system dominates by controlling the process and the operating conditions, can realize synchronous nitrogen and phosphorus removal under the condition of low carbon source, and realizes 'one carbon dual-purpose'; the mixed liquid in the aerobic pool flows back to the anoxic pool and the facultative pool through the air lifter, and the facultative pool can induce the DPB to become a dominant flora to play a role in denitrifying and phosphorus accumulating under the condition of low C/N by controlling oxidation-reduction potential and dissolved oxygen, and strengthens the synchronous nitrification and denitrification; the sludge in the sedimentation tank flows back to the adsorption tank, and organic matters are quickly adsorbed to prevent the sludge from expanding; NO carried in sludge₃ ^-And DO flows back to the anaerobic tank after being subjected to denitrification in the anoxic tank, so that NO is eliminated to the maximum extent₃ ^-And DO inhibits DPB and phosphorus accumulating bacteria PAOs, so as to create a 'depression' environment for DPB anaerobic phosphorus release; alternative anaerobic/anoxic enrichment of DPB to maximize NO elimination₃ ^-And inhibition of DPB and PAOs by DO; the process equipment has good nitrogen and phosphorus removal effects under the condition of low C/N.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to these drawings without creative efforts.

FIG. 1 is a schematic plan view of an apparatus for treating domestic sewage with high efficiency denitrification and dephosphorization by enriching denitrifying phosphorus-accumulating bacteria disclosed in the embodiments of the present invention;

FIG. 2 is a schematic cross-sectional view of an A-A of an apparatus for treating domestic wastewater with high efficiency denitrification and dephosphorization by enriching denitrifying phosphorus-accumulating bacteria disclosed in the embodiments of the present invention;

FIG. 3 is a schematic sectional view of a B-B of an efficient denitrification and dephosphorization domestic sewage treatment device for enriching denitrifying phosphorus accumulating bacteria disclosed by the embodiment of the invention.

The corresponding part names indicated by the numbers and letters in the drawings:

1. a tank body 2, an anaerobic tank 3, an adsorption tank 4, an anoxic tank

5. Facultative tank 6, aerobic tank 7, dissolved oxygen instrument 8, sedimentation tank water inlet channel

9. Sedimentation tank 10, water outlet channel 11, air lifting and pushing device 12 and return channel

13. Sludge scraping and sucking machine 14, sludge return channel 15, water inlet pipe 16 and water outlet pipe

17. Residual sludge pipe 18, air inlet pipe 19, submersible plug flow stirrer 20 and submersible stirrer

21. Reflux pump 22, aerator 23, canal gate 24 and communicating pipe

25. Electric valve 26, stainless steel net 27, oxidation-reduction potentiometer 28 and water distribution hole

29. Flap valve 30, filler 31, water through hole 32 and hydraulic baffle

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. 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.

According to the figures 1, 2 and 3, the invention provides a high-efficiency denitrification and dephosphorization domestic sewage treatment device for enriching denitrifying phosphorus-accumulating bacteria, which comprises a tank body 1, a rectangular carbon steel structure without a top cover, and a channel length-width ratio of 5: 1-10: 1, width-depth ratio of 1: 1-2: 1; the tank body comprises an anaerobic tank 2, an adsorption tank 3, an anoxic tank 4, a facultative tank 5, an aerobic tank 6 and a sedimentation tank 9, water passing holes 31 are arranged among the tanks, and the hydraulic form is a plug flow type. The starting end of the anaerobic tank 2 is provided with a water inlet pipe 15 and a submersible plug flow stirrer 19, and the tail end is provided with an oxidation-reduction potentiometer 27; the center of the adsorption tank 3 is provided with a submersible stirrer 20, the stirrer is provided with an upper blade and a lower blade, and one side close to the sedimentation tank 9 is provided with a sludge return hole 31; the starting end of the anoxic pond 4 is provided with a diving plug flow stirrer 19 and an aerobic pond mixed liquid return channel 12, the bottom of the return channel 12 is provided with a communicating pipe 24 leading to the bottom of the anoxic pond 4, the tail end of the anoxic pond 4 is provided with an oxidation-reduction potentiometer 27 and a diving return pump 21, the outlet of the return pump is arranged at the starting end of the anaerobic pond 2, and a flap valve 29 is arranged; the facultative tank is divided into 2 lattices, the beginning end of each lattice is provided with a submersible plug flow stirrer 19, the bottom is provided with an aerator 22, and the tail end of the second lattice is provided with an oxidation-reduction potentiometer 27 and a dissolved oxygen instrument 7; the aerobic pool 6 is divided into 2 grids, the bottom of each grid is provided with an aerator 22, moving bed fillers 30 are arranged in the pool, the tail ends of the moving bed fillers are provided with a dissolved oxygen instrument 7 and an air lifter 11, mixed liquid passes through the air lifter 11 to a return channel 12, and a stainless steel net is arranged between the air lifter and the aerobic pool 6 to prevent the moving bed fillers 30 from entering the air lifter; a channel gate 23 is arranged on a mixed liquid return channel 12 leading to the facultative tank 5 and the anoxic tank 4 and used for adjusting the return flow; the sedimentation tank 9 adopts the long limit form of intaking in the outside, long limit play water, and 8 below of the channel of intaking are equipped with the water distribution hole 28, and there is water conservancy baffle 32 water distribution hole 28 below, and mud scrapes suction dredge 13 through the driving and discharges into mud backward flow canal 14, and backward flow mud gets into adsorption tank 3 through the water hole 31 of crossing on the adsorption tank 3, and surplus mud is discharged through the terminal mud pipe 17 of backward flow mud canal 14. The water inlet pipe 15, the water outlet pipe 16, the air inlet pipe 18 and the sludge discharge pipe 17 are respectively provided with an electric valve 25.

The method comprises the following specific operation steps:

1. opening a water inlet valve, injecting domestic sewage, inoculating residual sludge of a domestic sewage plant to the equipment for circulating operation, adding methanol, ammonium nitrate and potassium dihydrogen phosphate, adjusting the concentration of C to N to be (4-5): 1 and the concentration of C to P to be (17-20): 1 to ensure that the concentration of the sludge in the equipment reaches 2000 mg/L-3000 mg/L, monitoring a water outlet of the equipment, and successfully starting the equipment when the TN removal rate is more than 70 percent and the TP removal rate is more than 50 percent;

2. continuously feeding water, regulating and controlling the return flow of mixed liquor in the aerobic pool and the aeration time of the facultative pool to control the ORP of the anaerobic pool to be-450 mV to-250 mV, the ORP of the anoxic pool to be-150 mV to 0mV, the ORP of the facultative pool to be-100 mV to 50mV, the DO of the facultative pool to be less than 0.6 mg/L and the DO of the aerobic pool to be 1.5-2.5 mg/L, regulating and controlling the return flow of residual sludge to be 50-100 percent, monitoring the concentration of pollutants at a water outlet until TP is less than or equal to 0.5 mg/L, TN is less than or equal to 10 mg/L and NH is less than or equal to₄ ⁺Until the concentration is less than or equal to 3 mg/L;

3. after the adjustment, the equipment achieves the stable operation, the facultative tank aeration time and the mixed liquid reflux amount are controlled according to the setting P L C, and the facultative tank aeration control mode is that NH is used as effluent₄ ⁺At most 3 mg/L, aeration is started under three conditions that DO of an aerobic pool ① is less than 1.5 mg/L, ORP of a facultative pool ② is less than-100 mV, OPR of an anoxic pool ③ is less than-150 mV, and NH is discharged₄ ⁺When the concentration is more than 3 mg/L, the facultative tank is aerated until water NH is discharged₄ ⁺Less than or equal to 3 mg/L, NH when yielding water₄ ⁺When the concentration is less than or equal to 3 mg/L, the aeration is closed under the two conditions that DO of the ① facultative tank is more than 0.6 mg/L, ORP of the ② facultative tank is more than 50 mV;

when the OPR of the anoxic pond is less than-150 mV, the flow rate of the anoxic pond is properly increased by increasing the opening of the canal gate; when the ORP of the facultative tank is less than-100 mV, properly increasing the reflux amount of the facultative tank by increasing the opening of the canal gate; when the OPR of the anoxic pond is more than 0mV, the return flow to the anoxic pond is properly reduced by reducing the opening of the canal gate; when the ORP of the facultative tank is more than 50mV, the return flow to the facultative tank is appropriately reduced by reducing the opening of the channel gate.

Through the specific embodiment, the beneficial effects of the invention are as follows: the nitrogen and phosphorus removal equipment has high integrated degree and good nitrogen and phosphorus removal effect under the condition of low C/N; the nitrogen and phosphorus removal equipment controls the process and the running conditions to make the DPB in the system dominate, can realize synchronous nitrogen and phosphorus removal under the condition of low carbon source, and realizes 'one carbon dual-purpose'; the mixed liquid in the aerobic tank flows back to the aerobic tank through the air lifterThe facultative tank can induce the DPB to become dominant flora to play a role in denitrifying phosphorus accumulation under the condition of low C/N by controlling oxidation-reduction potential, and strengthens the synchronous nitrification-denitrification; the sludge in the sedimentation tank flows back to the adsorption tank, and organic matters are quickly adsorbed to prevent the sludge from expanding; NO carried in sludge₃ ^-The nitrogen is refluxed to the anaerobic tank after being denitrified by the anoxic tank, and NO is eliminated to the maximum extent₃ ^-And DO inhibits DPB and phosphorus accumulating bacteria PAOs, so as to create a 'depression' environment for DPB anaerobic phosphorus release; the alternative anaerobic/anoxic can enrich DPB, and the process equipment has good nitrogen and phosphorus removal effects under the condition of low C/N.

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

Claims

1. An efficient denitrification and dephosphorization domestic sewage treatment device for enriching denitrification phosphorus-accumulating bacteria, which is called denitrification and dephosphorization device for short; it is characterized by comprising a tank body, an anaerobic tank, an adsorption tank, an anoxic tank, a facultative tank, an aerobic tank and a sedimentation tank; the nitrogen and phosphorus removal equipment is of a rectangular carbon steel structure, and the tank body is integrally assembled by a plurality of open channels without top covers; the aspect ratio of the channel of the nitrogen and phosphorus removal equipment is 5: 1-10: 1, and the width-depth ratio is 1: 1-2: 1; a sedimentation tank is arranged on the left side of the tank body, a facultative tank is arranged on the right side of the tank body, an anaerobic tank and an anoxic tank are arranged in parallel on the lower middle part, and an aerobic tank is arranged in parallel on the upper middle part; an adsorption tank is arranged above the anaerobic tank; backflow channels are arranged on the left side and the periphery of the upper part of the inner side of the tank body; a water outlet channel is arranged on the right side of the inner side of the tank body; the upper part and the left side of the outer side of the tank body are respectively provided with two groups of air inlet pipes, and the lower part of the outer side of the tank body is respectively provided with a water inlet pipe, a water outlet pipe and a residual sludge pipe; an air ejector is arranged at the upper left corner in the tank body;

water through holes are formed among the anaerobic tank, the adsorption tank, the anoxic tank, the facultative tank, the aerobic tank and the sedimentation tank, and the hydraulic form is plug flow type; the starting end of the anaerobic tank is provided with a water inlet pipe and a submersible plug flow stirrer, and the tail end of the anaerobic tank is provided with an oxidation-reduction potentiometer; a submersible stirrer is arranged in the center of the adsorption tank, the submersible stirrer is provided with an upper group of blades and a lower group of blades, and a water passing hole arranged on one side of the adsorption tank, which is close to the sedimentation tank, is used as a sludge return hole; the starting end of the facultative tank is provided with a submersible plug flow stirrer, and the starting end of the facultative tank is communicated with the return channel of the mixed liquid in the aerobic tank through a water through hole; a pipeline leading to the bottom of the anoxic tank is arranged at the bottom of the backflow channel, an ORP (oxidation-reduction potential) instrument and a submersible backflow pump are arranged at the tail end of the backflow channel, and an outlet of the backflow pump is positioned at the starting end of the anaerobic tank and is provided with a flap valve; the facultative tank is respectively provided with two grids which are arranged in series front and back, the starting end of each grid is provided with a submersible plug flow stirrer, the bottom of each grid is provided with an aerator, and the tail end of the second grid of the facultative tank is provided with an ORP (oxidation-reduction potential) instrument and a dissolved oxygen instrument; the aerobic tank is divided into two grids which are arranged in parallel and in series, an aerator is arranged at the bottom of each grid, moving bed fillers are filled in the aerobic tank, a DO instrument and an air lifter are arranged at the tail end of the second grid of the aerobic tank, and the mixed liquor in the aerobic tank flows to a return channel through the air lifter; a stainless steel mesh is arranged between the air lifter and the aerobic tank, and the stainless steel mesh prevents the moving bed filler from entering the area of the air lifter; a channel gate is arranged on a return channel of the mixed liquid which is led to the facultative tank and the anoxic tank, and the channel gate adjusts the return flow; the sedimentation tank adopts the form of outside long-edge water inlet and long-edge water outlet, a water distribution hole is arranged below a water inlet channel of the sedimentation tank, a hydraulic baffle is arranged below the water distribution hole, sludge in the sedimentation tank is discharged into a sludge return channel through a travelling sludge scraping and sucking machine, the returned sludge enters the adsorption tank through a sludge return hole on the adsorption tank, and residual sludge is discharged through a residual sludge pipe at the tail end of the channel; the whole process is controlled by three ORP instruments and two DO instruments, and the total effluent quality index NH₄ ⁺＜3mg/L，TN＜10mg/L，TP＜0.5mg/L。

2. The apparatus for high-efficiency denitrification and dephosphorization domestic sewage treatment with enrichment of denitrifying phosphorus accumulating bacteria as claimed in claim 1, wherein the hydraulic retention time of the anaerobic tank, the adsorption tank, the anoxic tank, the facultative tank, the aerobic tank and the sedimentation tank is 1.5h, 0.3h, 2h, 6h and 2h respectively; the surface load of the sedimentation tank is 0.8m³/㎡·h—1.2m³The ORP control range of the anaerobic tank is-450 mV to-250 mV, the ORP control range of the anoxic tank is-150 mV to 0mV, the ORP control range of the facultative tank is-100 mV to 50mV, the DO control range of the facultative tank is less than 0.6 mg/L, and the DO control range of the aerobic tank is 1.5 mg/L-2.5 mg/L.

3. The apparatus for high efficiency denitrification and dephosphorization wastewater treatment based on the enrichment of denitrifying phosphorus accumulating bacteria as claimed in claim 1, wherein the submerged agitator in the adsorption tank adopts a low speed agitator, and the agitation speed is 40r/min to 60 r/min; the unit power of the submersible plug flow stirrer in the anaerobic tank, the anoxic tank and the facultative tank is 2W/m³—4W/m³(wastewater).

4. The apparatus for treating domestic sewage with high efficiency nitrogen and phosphorus removal enriched with denitrifying phosphorus-accumulating bacteria as claimed in claim 1, wherein the anoxic tank flows back to the anaerobic tank with a reflux ratio of 100%; the sludge in the sedimentation tank flows back to the adsorption tank, the reflux ratio is 50% -100%, the DPB is alternately enriched in anaerobic/anoxic volume through reflux, and NO is eliminated to the maximum extent through the mode that the mixed liquor in the anoxic tank flows back to the anaerobic tank₃ ^-And DO inhibition of DPB and PAOs.

5. The apparatus for treating domestic sewage with high efficiency nitrogen and phosphorus removal enriched with denitrifying phosphorus-accumulating bacteria as claimed in claim 1, wherein the facultative tank adopts an intermittent aeration mode, the mixed liquor of the anoxic tank and the mixed liquor of the aerobic tank return flow together enter the facultative tank, under the condition of low C/N ratio, DPB is induced to become dominant flora, the synchronous nitrogen and phosphorus removal operation is realized, and the apparatus has the characteristic of one carbon and two purposes; and enhances the synchronous nitrification-denitrification (SND) of the facultative denitrifying bacteria under the low DO condition.

6. The apparatus of claim 1, wherein the facultative tank is aerated in NH (ammonia-nitrogen) as effluent₄ ⁺When the concentration of the wastewater is less than or equal to 3 mg/L, aeration is started under the following three conditions that the DO of the aerobic pool ① is less than 1.5 mg/L, the ORP of the facultative pool ② is less than-100 mV, the OPR of the anoxic pool ③ is less than-150 mV, and NH in effluent₄ ⁺When the concentration is more than 3 mg/L, starting aeration of the facultative tank until NH in effluent is discharged₄ ⁺Less than or equal to 3 mg/L, NH when yielding water₄ ⁺And when the concentration is less than or equal to 3 mg/L, the aeration is closed under the following two conditions that the DO of the facultative tank ① is more than 0.6 mg/L, and the ORP of the facultative tank ② is more than 50 mV.

7. The apparatus for treating domestic sewage with high efficiency nitrogen and phosphorus removal rich in denitrifying phosphorus-accumulating bacteria as claimed in claim 1, wherein the aerobic tank is provided with moving bed packing and nitrifying bacteria (NOB) with longer fixed sludge age, and the packing ratio of the packing is 20-50%; the reflux of the mixed liquid in the aerobic tank adopts an air stripping mode, and the reflux ratio range is 100-400%; the reflux quantity of the mixed liquid in the aerobic tank is realized by controlling the air blower to increase or decrease the air quantity supplied to the air stripping pusher through the frequency converter.

8. The apparatus for treating domestic sewage with high efficiency nitrogen and phosphorus removal by enriching denitrifying phosphorus-accumulating bacteria of claim 1, wherein the reflux amount of the mixed liquid in the aerobic tank is controlled by increasing the opening of a canal gate and properly increasing the reflux amount to the anoxic tank when the OPR of the anoxic tank is less than-150 mV; when the ORP of the facultative tank is less than-100 mV, properly increasing the reflux amount to the facultative tank by increasing the opening of a channel gate; when the OPR of the anoxic pond is more than 0mV, properly reducing the reflux amount to the anoxic pond by reducing the opening of the canal gate; when the ORP of the facultative tank is more than 50mV, the return flow to the facultative tank is properly reduced by reducing the opening degree of a channel gate.