Double-source recarburization type low-carbon nitrogen and phosphorus removal device and method

Abstract

According to the double-source recarburization type low-carbon nitrogen and phosphorus removal device and method, a grit chamber is arranged at the front end of a system, most of inorganic particles in water are removed, and fine inorganic particles and organic suspended solids enter a biochemical pool; fine inorganic particles provide a natural carrier for microorganisms, and formation of heavy sludge is promoted; then entering an anaerobic stirring stage, fermenting and hydrolyzing suspended organic matters and activated sludge in the sewage, and carrying out anaerobic phosphorus release; then entering a low-oxygen and oxygen-deficiency alternating stage, carrying out low-oxygen nitrification, oxygen-deficiency endogenous denitrification and phosphorus uptake effects; then entering an oxygen-deficiency stage, and further carrying out endogenous denitrification for deep nitrogen removal; and finally entering a normal aeration stage for degassing to improve the sludge settleability. Dependence on external carbon addition can be reduced, endogenous fermentation of the activated sludge is triggered in the anaerobic stage, an'exogenous + endogenous' composite recarburization channel is formed, sufficient electron donors are provided for subsequent anoxic endogenous denitrification and phosphorus uptake, and therefore stable deep nitrogen removal and phosphorus removal are achieved under the low-carbon condition.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment, and more specifically, it relates to a thermal zone dual-source carbon-enhancing type low-carbon nitrogen and phosphorus removal device and method. Background Technology

[0002] Against the backdrop of increasingly stringent "dual carbon" targets and urban wastewater discharge standards, wastewater treatment processes urgently need to achieve deep nitrogen removal and phosphorus removal while reducing dependence on external carbon and aeration energy consumption. Sequencing Batch Reactors (SBRs) are widely used in small and medium-sized wastewater treatment plants and integrated systems due to their simple structure, flexible operation, and compact footprint. SBRs typically achieve nitrification, denitrification, and phosphorus release / uptake at different stages through a time-series cycle of "influent—reaction—sedimentation—effluent—idle."

[0003] However, under operating conditions where the influent C / N ratio is low or energy consumption is limited, existing SBRs generally face the following challenges: (1) Insufficient available carbon sources. Primary sedimentation tanks are often set up in engineering to reduce the suspended solids load, but at the same time, a large amount of particulate organic matter that can be hydrolyzed and fermented is retained at the front end, resulting in a lack of electron donors in the reaction tank, increasing the dependence of denitrification and phosphorus uptake processes on external carbon, and increasing operating costs and carbon footprint.

[0004] (2) Difficulty in balancing stage transitions and energy consumption. Relying solely on intermittent aeration or DO / ORP limit control can easily lead to excessive oxidation of endogenous organic matter during the aerobic stage, resulting in insufficient electron donors in the subsequent anoxic stage. In order to ensure effluent quality, the aeration intensity and duration are often increased, leading to increased energy consumption.

[0005] (3) Insufficient sludge settling properties and community stability. SBR operates intermittently in a single tank and usually lacks a selective separation / sludge discharge mechanism synchronized with the cycle to preferentially retain "heavy sludge" with high settling velocity and preferentially discharge "light sludge" in the long term; relying solely on SRT adjustment is insufficient to stably maintain the proportion and activity of functional bacteria such as nitrifying, denitrifying and polyphosphate accumulation, resulting in insufficient operational shock resistance.

[0006] (4) Insufficient utilization of natural high-temperature conditions in tropical (hot) regions. In tropical / subtropical regions, higher water temperatures accelerate the rate of biochemical reactions and intensify the consumption of organic matter by aerobic processes. Existing operating parameters mostly follow the experience of normal temperature regions, resulting in a shorter anaerobic phase and insufficient utilization of suspended organic matter and activated sludge through hydrolysis and fermentation. Consequently, the system fails to fully form usable organic matter such as volatile fatty acids (VFA) that can be utilized in subsequent anoxic phases.

[0007] (5) Insufficient carriers and framework. In actual water, tiny inorganic particles are often carried, but conventional pretreatment and primary sedimentation remove them along with the water. This results in a lack of inert cores in the reaction tank that can serve as a framework for microbial aggregation, which is not conducive to the formation of large aggregates with high settling rates (heavy sludge), thus affecting the efficiency of sludge-water separation and long-term stable operation.

[0008] To address the above issues, existing technologies have mainly attempted measures such as segmented water intake, intermittent aeration, low dissolved oxygen operation, external carbon source supplementation, setting selectors or external hydrolysis / fermentation units, but still have limitations such as high dependence on external carbon, difficulty in reducing energy consumption, difficulty in selectively managing heavy / light sludge in the tank, and failure to fully utilize the anaerobic hydrolysis and fermentation potential under hot zone conditions.

[0009] Therefore, this application proposes a dual-source carbon-enriched low-carbon nitrogen and phosphorus removal device and method that, in the time series of a single SBR tank, utilizes dual-source usable organic matter formed by the hydrolysis and fermentation of exogenous suspended organic matter and the endogenous fermentation of activated sludge, without setting up a primary sedimentation tank or reducing the front-end interception intensity, and achieves stable deep denitrification and phosphorus removal under low external carbon and low aeration conditions through a selective separation / sludge discharge strategy matched with the cycle and a reasonable good / anoxic sequence.

[0010] Therefore, this patent adopts a segmented influent endogenous short-cut denitrification and anaerobic ammonia oxidation method. It uses a cyclone separator and calcium ion addition to form granular sludge from activated sludge, providing a favorable growth environment for endogenous denitrifying bacteria, anaerobic ammonia oxidizing bacteria and phosphorus removal bacteria. This allows the various bacterial groups to cooperate with each other, make full use of the organic matter in the wastewater, and exert both autotrophic and heterotrophic denitrification effects, thereby achieving the goal of low-carbon and high-efficiency nitrogen and phosphorus removal. Summary of the Invention

[0011] The purpose of this invention is to provide a dual-source carbon-enhancing low-carbon nitrogen and phosphorus removal device and method, which significantly improves the efficiency of nitrogen and phosphorus removal while reducing energy consumption and carbon emissions, thereby effectively reducing treatment costs and land area, and providing a more economical, efficient and sustainable solution for urban sewage treatment.

[0012] To achieve the above objectives, the present invention provides the following technical solution: a dual-source carbon-enriching type low-carbon nitrogen and phosphorus removal device, comprising: The biological treatment tank is a single-chamber structure, and a dissolved oxygen probe is installed inside it. The sewage tank is located outside the biological treatment tank and is connected to the middle of the biological treatment tank through an inlet pipe. It is used to store sewage to be treated. A grit chamber is located outside the biological treatment tank and is connected to the sewage tank to remove inorganic particulate matter from the sewage. A hydrocyclone separator is installed on the side wall of the biological treatment tank. The side of the hydrocyclone separator is connected to the middle of the biological treatment tank through a sludge discharge valve, and the lower end of the hydrocyclone separator is connected to the lower part of the biological treatment tank through a return valve. The sedimentation tank provides wastewater to the sewage tank to remove large inorganic particles, and allows suspended organic matter and fine inorganic particles in the water to enter the biological treatment tank, providing a natural carrier for microorganisms. The hydrocyclone separator sorts and discharges the overflow light sludge to control the sludge age.

[0013] Furthermore, it also includes a stirrer, which is rotatably connected to the top of the biological treatment tank, and the stirring head of the stirrer extends downward into the interior of the biological treatment tank to continuously stir the contents of the tank; it also includes a solution tank, which is connected to the wastewater tank and supplies calcium chloride solution to the wastewater tank through a peristaltic pump; the upper end of the dissolved oxygen probe passes through the upper part of the biological treatment tank and is connected to an online sensor to monitor the dissolved oxygen concentration in real time.

[0014] Furthermore, an inlet flow regulating valve is installed inside the inlet pipe, an outlet valve is installed on the side of the biological tank, a microporous aeration head is installed at the bottom of the biological tank, an air intake device is installed at the lower part of the microporous aeration head extending to the outside of the biological tank, an air volume regulating valve is installed in the air intake channel, a discharge valve is also installed on the side of the cyclone separator, and a control cabinet is also included. The control cabinet is electrically connected to each component to perform logic control on each electric component.

[0015] A dual-source carbon-enrichment type low-carbon nitrogen and phosphorus removal method, using the above-mentioned apparatus, includes the following steps: S1: Low-carbon wastewater is passed through a grit chamber to remove large inorganic particles, while retaining small inorganic particles. The treated wastewater is then discharged into a wastewater tank. Calcium chloride solution is supplied to the wastewater in the tank through a solution tank to control the calcium ion concentration in the wastewater to 80-150 mg / L.

[0016] S2: Sewage in the sewage tank enters the biological treatment tank through the inlet pipe, and activated sludge from the sewage treatment plant is added to the biological treatment tank. S3: Start the agitator to stir the wastewater, so that the suspended organic matter in the wastewater and the activated sludge can be fermented and hydrolyzed. S4: The air intake device is turned on at short intervals, so that the microporous aeration head aerates at low oxygen intervals, forming a low oxygen section and anoxic section alternately; the dissolved oxygen concentration in the low oxygen section is controlled at 0.2-0.5mg / L.

[0017] S5: Shut down the air intake equipment and proceed with the oxygen-deficient phase reaction; S6: Turn on the air intake device to allow the microporous aeration head to perform normal aeration and form an aerobic reaction; the dissolved oxygen concentration in the aerobic zone is controlled at 2-3 mg / L.

[0018] S7: Settling is carried out. After the settling is completed, the water is drained through the outlet valve and the sludge is discharged through the sludge discharge valve. The cyclone separator sorts the sludge, and the light sludge is discharged through the discharge valve, while the heavy sludge is returned to the bottom of the biological treatment tank through the return valve for retention.

[0019] Furthermore, in step S4, the low-oxygen aeration time is controlled within the range of 5-9 minutes, and the aeration stop time is controlled within the range of 6-8 minutes. In step S7, the sludge retention time is controlled to be 10-15 days, and the total hydraulic retention time (HRT) of the biological treatment tank system is 8-13 hours, of which the HRT of the anaerobic section is 3-4 hours, the HRT of the low-oxygen-anoxic alternation section is 3-4 hours, the HRT of the anoxic section is 1-2 hours, and the HRT of the aerobic section is 0.5-1 hour.

[0020] Furthermore, the sludge concentration after water influent is controlled at 2200-4200 mg / L; continuous stirring is carried out by a stirrer throughout all reaction stages after water influent to ensure complete reaction.

[0021] Compared with existing technologies, it has the following beneficial effects: By installing a grit chamber at the front end of the system instead of a primary sedimentation tank, suspended organic matter in the influent can enter the biological treatment tank. Fine inorganic particles are also introduced, providing a natural carrier for microorganisms and promoting the formation of heavy sludge. After entering the biological treatment tank, the wastewater undergoes anaerobic stirring to ferment and hydrolyze the suspended organic matter and activated sludge, simultaneously releasing phosphorus. This is followed by an alternating low-oxygen and anoxic phase, where low-oxygen nitrification and anoxic endogenous denitrification and phosphorus uptake occur. Then, an anoxic phase further promotes endogenous denitrification for deep nitrogen removal. Finally, an aerobic section enhances biological phosphorus uptake and deaeration, improving sludge settling properties. After the reaction is complete, the system enters a sedimentation and sludge discharge phase, achieving nitrogen and phosphorus removal from the wastewater. During system operation, calcium ions are artificially added. These ions bridge extracellular polymers and microbial cells, promoting microbial aggregation and the formation of heavy sludge. The sludge is separated by a hydrocyclone separator. The sludge age is controlled by discharging the overflowing light sludge, while the bottom flow of heavy sludge is returned to the biological treatment tank instead of being discharged from the system. This allows the heavy sludge to remain in the system for a longer period, improving the overall sludge settling performance and preventing bulking problems. The long-term retention of heavy sludge in the system also increases the abundance of functional bacteria in the sludge.

[0022] Compared with the traditional A2O process, this method has the following advantages: 1) By using tiny inorganic particles in the raw water as a carrier and combining them with sludge discharge by a hydrocyclone separator, the retention of heavy sludge in the system is promoted, the abundance of functional bacteria in the sludge is increased, thereby improving the denitrification rate and also improving the sludge settling properties.

[0023] 2) Dual-source carbon enhancement and reduced dependence on external carbon: By eliminating the need for primary sedimentation, suspended organic matter enters the biological treatment tank with the water. At the same time, during the anaerobic stage, the activated sludge is triggered to undergo endogenous fermentation to generate VFA, forming a composite carbon enhancement channel of "exogenous + endogenous". This provides sufficient electron donors for subsequent anoxic endogenous denitrification and phosphorus uptake, thereby achieving stable deep denitrification and phosphorus removal under low-carbon conditions.

[0024] 3) Low-oxygen operation reduces system energy consumption.

[0025] 4) The carbon source in the sludge is used for denitrification, resulting in less sludge production in the system. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only preferred embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a schematic diagram of the overall structure of a dual-source carbon-enriched low-carbon denitrification and phosphorus removal device according to the present invention.

[0028] In the diagram: 1. Grit chamber; 2. Wastewater tank; 3. Biological treatment tank; 4. Inlet pipe; 5. Solution tank; 6. Hydrocyclone separator; 7. Control cabinet; 8. Air intake device; 9. Agitator; 10. Online sensor; 11. Microporous aerator head; 12. Air volume regulating valve; 13. Dissolved oxygen probe; 14. Peristaltic pump; 15. Inlet flow regulating valve; 16. Outlet valve; 17. Sludge discharge valve; 18. Return valve; 19. Discharge valve. Detailed Implementation

[0029] To better understand the structure, functional features, and advantages of the present invention, preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings: When using the process of this invention, urban sewage first enters the grit chamber 1, where most of the inorganic particulate matter is removed before flowing into the sewage tank 2. Subsequently, the sewage enters the biological treatment tank 3 through the influent flow regulating valve 15, and then enters the reaction stage. In the anaerobic stirring stage, organic suspended solids and activated sludge undergo fermentation and hydrolysis, while an anaerobic phosphorus release process occurs simultaneously. Then, it enters a low-oxygen and anoxic alternating stage, where low-oxygen nitrification and anoxic endogenous denitrification and phosphorus uptake occur. Then, it enters an anoxic stage for further endogenous denitrification and deep nitrogen removal. Finally, it enters a normal aeration stage for deaeration to improve sludge settling properties. Afterward, it enters the sedimentation stage, where sludge and water are separated, and the supernatant is discharged through the drain valve. The settled sludge is sent to the hydrocyclone separator 6 through the sludge discharge valve 17 for classification. Light sludge overflows and is discharged as residual sludge through the discharge valve 19, while the bottom heavy sludge is returned to the bottom of the biological treatment tank 3 through the return valve 18, achieving the retention and recycling of functional microbial communities. During operation, the addition of Ca²⁺ promotes the binding of extracellular polymers with microbial cells, thereby facilitating the aggregation of activated sludge and promoting the formation of heavy sludge. Thus, the entire process can stably achieve nitrogen and phosphorus removal under low-carbon conditions.

[0030] Example 1 like Figure 1 As shown, this application proposes a dual-source carbon-enriched low-carbon nitrogen and phosphorus removal device, comprising: Biological tank 3 is a single-chamber structure, and a dissolved oxygen probe 13 is installed inside it to monitor the dissolved oxygen concentration in the reaction in real time, so as to control the occurrence time and switching between the anoxic and aerobic reaction stages.

[0031] Wastewater tank 2 is located outside the biological treatment tank 3. Wastewater tank 2 is connected to the middle of the biological treatment tank 3 through water inlet pipe 4 and is used to store wastewater to be treated. Low-carbon urban wastewater is introduced into wastewater tank 2. Wastewater tank 2 is made of corrosion-resistant and chemically stable material to avoid the wastewater reacting with the material of wastewater tank 2 due to long-term storage of wastewater.

[0032] Grit chamber 1 is located outside biological treatment tank 3 and is connected to sewage tank 2 to remove inorganic particulate matter from sewage. Grit chamber 1 can be horizontal flow or vortex flow type, and large inorganic particulate matter is separated by gravity or centrifugal force.

[0033] A hydrocyclone separator 6 is installed on the side wall of the biological treatment tank 3. The side of the hydrocyclone separator 6 is connected to the middle of the biological treatment tank 3 through a sludge discharge valve 17, and the lower end of the hydrocyclone separator 6 is connected to the lower part of the biological treatment tank 3 through a return valve 18. The hydrocyclone separator 6 is a hydraulic hydrocyclone separator 6, which separates the sludge by using its shear force and centrifugal force. The upper mixed liquor suspended sludge, i.e., light sludge, is separated and discharged, while the heavy sludge is returned.

[0034] The sedimentation tank provides wastewater to the sewage tank 2 to remove large inorganic particles, and allows suspended organic matter and fine inorganic particles in the water to enter the biological treatment tank 3, providing a natural carrier for microorganisms. The cyclone separator 6 sorts and discharges the overflow light sludge to control the sludge age.

[0035] The existing sedimentation tank 1 can remove sand particles with a diameter of 0.21 mm or larger, while the removal rate of tiny sand particles with a diameter between 0.11 and 0.21 mm is about 70%. Therefore, some fine inorganic particles can enter the reaction stage and provide a carrier for microorganisms.

[0036] See Figure 1 It also includes a stirrer 9, which is rotatably connected to the top of the biological tank 3. The stirring head of the stirrer 9 extends downward into the interior of the biological tank 3 to continuously stir the contents of the biological tank 3. It also includes a solution tank 5, which is connected to the sewage tank 2 and supplies calcium chloride solution to the sewage tank 2 through a peristaltic pump 14. The upper end of the dissolved oxygen probe 13 passes through the upper part of the biological tank 3 and is connected to an online sensor 10 to monitor the dissolved oxygen concentration in real time.

[0037] See Figure 1 The inlet pipe 4 is equipped with an inlet flow regulating valve 15, the side of the biological tank 3 is equipped with an outlet valve 16, the bottom of the biological tank 3 is equipped with a microporous aeration head 11, the lower part of the microporous aeration head 11 extends to the outside of the biological tank 3 and is equipped with an air intake device 8, the air intake channel is equipped with an air volume regulating valve 12, and the side of the cyclone separator 6 is also equipped with a discharge valve 19.

[0038] See Figure 1 It also includes a control cabinet 7, which is electrically connected to electrical components such as online sensor 10, air intake device 8, cyclone separator 6, water inlet flow regulating valve 15, water outlet valve 16, peristaltic pump 14 and agitator 9, and adopts chip-type logic control.

[0039] Example 2 A dual-source carbon-enriched low-carbon nitrogen and phosphorus removal method is proposed, using the dual-source carbon-enriched low-carbon nitrogen and phosphorus removal device described in Example 1. This embodiment uses the effluent from the grit chamber 1 of a wastewater treatment plant as the influent. The specific water quality is as follows: influent ammonia nitrogen 15.5-31.69 mg / L, influent total nitrogen (TN) 16.54-36.29 mg / L, influent total phosphorus 2.17-4.57 mg / L, influent COD (chemical oxygen demand) 52.79-133.47 mg / L, and an average C / N ratio of 3.7. The experimental system is as follows: Figure 1 As shown, the total reaction volume of the reactor is 15.8 L.

[0040] (1) Start the system: Inoculate the activated sludge from the sewage treatment plant into the biological treatment tank 3 to make the sludge concentration in the biological treatment tank 3 3000mg / L; (2) The adjustment operation during operation is as follows: 1) The total HRT of the biological tank 3 system is 10h, of which the HRT of the anaerobic section is 4h, the HRT of the low oxygen and anoxic alternation section is 3h, the HRT of the anoxic section is 2h, and the HRT of the aerobic section is 1h. 2) During the alternating low-oxygen and low-oxygen phases of the biological tank 3, low oxygen (DO of 0.2-0.45 mg / L) is maintained by turning on aeration and stirring, and an anoxic environment is achieved by stopping aeration and maintaining stirring. The duration of a single low-oxygen aeration is 7 minutes, and the duration of a single aeration stop is 7 minutes. During the anoxic phase, stirring is maintained but no aeration is performed. During the aerobic phase, aeration is performed while stirring is performed to make the dissolved oxygen concentration 2-3 mg / L.

[0041] 3) Before the reaction, calcium chloride solution was added to wastewater tank 2 to make the concentration of calcium ions in the influent 110 mg / L, and this was done continuously every day; 4) Discharge the light sludge overflowing from the 6-stage separation of the cyclone separator, and control the sludge age of the system to 12 days.

[0042] The test results show that after the system is in stable operation, the effluent ammonia nitrogen is less than 0.30 mg / L, effluent TN is less than 4.10 mg / L, effluent total phosphorus is less than 0.22 mg / L, and effluent COD is less than 24.65 mg / L.

[0043] Comparative Study Example 1 The process of this comparative study example differs from that of Example 2 of this application in that: this comparative example uses the traditional A2O process of a wastewater treatment plant in a hot zone, does not use the hydrocyclone separator 6 for sludge separation, does not add calcium chloride solution, and the wastewater quality and ambient temperature are the same as in Example 2. It mainly includes an anaerobic tank, an anoxic tank, an aerobic tank, and a secondary sedimentation tank. Wastewater first enters the anaerobic tank for anaerobic phosphorus release, then enters the anoxic tank for denitrification, and finally enters the aerobic tank for ammonia oxidation and aerobic phosphorus uptake. The sludge-water mixture is separated in the secondary sedimentation tank and the supernatant is discharged. The settled sludge is returned to the anaerobic tank. At the same time, a nitrification liquid return system is also set up, that is, the sludge-water mixture in the aerobic tank is returned to the anoxic tank.

[0044] The maximum TN concentration in the effluent of this comparative study was 6.82 mg / L, which is much higher than the maximum TN concentration of 4.1 mg / L in the effluent of Example 2.

[0045] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. Therefore, any modifications, equivalent changes, and alterations made to the above embodiments based on the technology of the present invention without departing from the scope of the present invention are within the protection scope of the present invention.

Claims

1. A dual-source carbon-enrichment type low-carbon nitrogen and phosphorus removal device, characterized in that, include: Biological tank (3), wherein the biological tank (3) is a single-chamber structure and a dissolved oxygen probe (13) is installed inside it; A sewage tank (2) is located outside the biochemical tank (3). The sewage tank (2) is connected to the middle of the biochemical tank (3) through an inlet pipe (4) and is used to store sewage to be treated. A sedimentation tank (1) is located outside the biochemical tank (3). The sedimentation tank (1) is connected to the sewage tank (2) to remove inorganic particulate matter from the sewage. A hydrocyclone separator (6) is installed on the side wall of the biological tank (3). The side of the hydrocyclone separator (6) is connected to the middle of the biological tank (3) through a sludge discharge valve (17). The lower end of the hydrocyclone separator (6) is connected to the lower part of the biological tank (3) through a return valve (18). The sedimentation tank provides wastewater to the wastewater tank (2) to remove particulate inorganic matter, and allows suspended organic matter and unremoved fine inorganic matter in the water to enter the biochemical tank (3) to provide a natural carrier for microorganisms. The cyclone separator (6) sorts and discharges overflow light sludge to control sludge age.

2. The dual-source carbon-enrichment type low-carbon nitrogen and phosphorus removal device according to claim 1, characterized in that, It also includes a stirrer (9), which is rotatably connected to the top of the biochemical tank (3). The stirring head of the stirrer (9) extends downward into the interior of the biochemical tank (3) to continuously stir the contents of the biochemical tank (3). It also includes a solution tank (5), which is connected to the sewage tank (2) and supplies calcium chloride solution to the sewage tank (2) through a peristaltic pump (14). The upper end of the dissolved oxygen probe (13) passes through the upper part of the biochemical tank (3) and is connected to an online sensor (10) to monitor the dissolved oxygen concentration in real time.

3. The dual-source carbon-enrichment type low-carbon nitrogen and phosphorus removal device according to claim 2, characterized in that, The inlet pipe (4) is equipped with an inlet flow regulating valve (15), the side of the biochemical tank (3) is equipped with an outlet valve (16), the bottom of the biochemical tank (3) is equipped with a microporous aeration head (11), the lower part of the microporous aeration head (11) extends to the outside of the biochemical tank (3) and is equipped with an air intake device (8), the air intake channel is equipped with an air volume regulating valve (12), and the side of the cyclone separator (6) is also equipped with a discharge valve (19).

4. The dual-source carbon-enrichment type low-carbon nitrogen and phosphorus removal device according to claim 3, characterized in that, It also includes a control cabinet (7), which is electrically connected to each component to perform logic control on each electric component.

5. A dual-source carbon-enriched low-carbon denitrification and phosphorus removal method, using the dual-source carbon-enriched low-carbon denitrification and phosphorus removal device as described in claim 4, characterized in that; Includes the following steps: S1: The low-carbon wastewater is passed through the sedimentation tank (1) to remove large inorganic particles, while retaining small inorganic particles. The treated wastewater is then discharged into the wastewater tank (2). Calcium chloride solution is supplied to the wastewater in the wastewater tank (2) through the solution tank (5) to control the calcium ion concentration in the wastewater to be 80-150 mg / L. S2: Sewage in the sewage tank (2) enters the biological treatment tank (3) through the inlet pipe (4), and activated sludge from the sewage treatment plant is added to the biological treatment tank (3); S3: Start the agitator (9) to agitate the wastewater, so that the suspended organic matter in the wastewater and the activated sludge ferment and hydrolyze. S4: The air intake device (8) is turned on at short intervals, so that the microporous aeration head (11) aerates at low oxygen intervals, forming a low oxygen section and anoxic section alternately; wherein the dissolved oxygen concentration in the low oxygen section is controlled at 0.2-0.5 mg / L. S5: Close the air intake device (8) and proceed with the oxygen-deficient stage reaction; S6: Turn on the air intake device (8) so that the microporous aeration head (11) can perform normal aeration to form an aerobic reaction; the dissolved oxygen concentration in the aerobic section is controlled at 2-3 mg / L. S7: Settling is carried out. After the settling is completed, the water is drained through the outlet valve (16) and the sludge is discharged through the sludge discharge valve (17). The cyclone separator (6) sorts the sludge, and the light sludge is discharged through the discharge valve (19). The heavy sludge is returned to the bottom of the biological tank (3) through the return valve (18) for retention.

6. The dual-source carbon-enrichment type low-carbon nitrogen and phosphorus removal method according to claim 5, characterized in that, In step S4, the low-oxygen aeration time is controlled within the range of 5-9 minutes, and the aeration stop time is controlled within the range of 6-8 minutes.

7. The dual-source carbon-enrichment type low-carbon nitrogen and phosphorus removal method according to claim 5, characterized in that, In step S7, the sludge retention time is controlled to be 10-15 days.

8. The dual-source carbon-enrichment type low-carbon nitrogen and phosphorus removal method according to claim 5, characterized in that, The total hydraulic retention time (HRT) of the biological treatment tank (3) system is 8-13h, of which the HRT of the anaerobic section is 3-4h, the HRT of the low oxygen and anoxic alternation section is 3-4h, the HRT of the anoxic section is 1-2h, and the HRT of the aerobic section is 0.5-1h.

9. The dual-source carbon-enrichment type low-carbon nitrogen and phosphorus removal method according to claim 5, characterized in that, The sludge concentration after influent is controlled at 2200-4200 mg / L.

10. The dual-source carbon-enriched low-carbon nitrogen and phosphorus removal method according to claim 5, characterized in that... ； After water is introduced, the agitator (9) continuously stirs the mixture throughout the entire reaction process to ensure that the reaction is complete.

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