Starch fermentation liquor coupling short path nitrification and enhanced biological phosphorus removal system and method

Abstract

The present application relates to a system and method for coupling short-cut nitrification and enhanced biological phosphorus removal by using starch fermentation liquor, and relates to the field of biological wastewater treatment. The system of the present application uses starch fermentation liquor to couple short-cut nitrification and enhanced biological phosphorus removal, avoids the interference of phosphorus in the carbon source of traditional fermentation liquor, significantly improves the metabolic activity of polyphosphorus bacteria and the tolerance of free nitrous acid, and realizes stable coupling of short-cut nitrification and efficient phosphorus removal in low carbon-nitrogen ratio municipal wastewater treatment. The present application has a wide source of raw materials, can realize "waste treatment with waste" by using starch processing wastewater, has significant economic and environmental benefits, and has good application prospect in the field of environmental microorganisms.

Description

Technical Field

[0001] This invention relates to the field of wastewater biological treatment technology, specifically to a system and method for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth. Background Technology

[0002] Starch, as a soluble macromolecular organic compound, has been preliminarily explored in enhanced biological phosphorus removal systems (EBPR). Existing research shows that using soluble starch as the sole carbon source, efficient phosphorus removal can be achieved in SBR denitrification systems operating in anoxic-aerobic alternation, with a phosphorus removal rate of up to 72%. Studies indicate that this phosphorus removal mechanism differs from traditional EBPR (anaerobic phosphorus release / aerobic phosphorus uptake dependent on PAOs) and denitrification phosphorus removal, and may involve intermediate products such as lactic acid produced after starch hydrolysis as a carbon source. Although existing research has shown that starch can be used as a carbon source for EBPR, these studies have the following significant shortcomings: (1) the phosphorus removal efficiency is low (only 72%), far from meeting the engineering requirements for efficient phosphorus removal; (2) the research focuses on supplementing carbon sources and does not involve using starch fermentation to achieve short-cut nitrification; (3) it does not explore whether the tolerance of PAOs to FNA will evolve and improve under long-term conditions of using starch fermentation broth as a carbon source; (4) it does not apply starch fermentation broth as a carbon source in the coupling system of short-cut nitrification and EBPR. Therefore, existing technologies cannot answer whether long-term domestication with phosphorus-free starch fermentation broth containing compound VFAs can enrich PAOs microbial communities with higher FNA tolerance, thereby achieving a stable coupling of short-cut nitrification and efficient phosphorus removal in a single A / O reactor.

[0003] Short-cut nitrification technology has attracted much attention due to its significant reduction in energy consumption (approximately 25% reduction in aeration volume) and carbon source consumption. Currently, some studies have attempted to couple short-cut nitrification with EBPR. A patent discloses a device and method for simultaneously denitrifying and denitrifying low C / N ratio wastewater using enhanced biological phosphorus removal coupled with simultaneous short-cut nitrification and denitrification. This method achieves short-cut nitrification through low-oxygen aeration (DO controlled at 0.5-1.0 mg / L), while polyphosphate-accumulating bacteria decompose PHA for aerobic phosphorus uptake, achieving simultaneous nitrogen and phosphorus removal in low C / N ratio wastewater without external carbon source conditions. However, its drawback lies in the strong inhibitory effect of free radical oxidizing agents (FNA) on the synthetic metabolic processes of conventional polyphosphate-accumulating organisms (PAOs) (growth, phosphate uptake, and glycogen production), especially at FNA concentrations of approximately 0.5 × 10⁻⁶. -3 mg HNO2 -A 50% inhibition can be achieved at -N / L. However, nitrite accumulation is inevitable during short-cut nitrification, and the resulting FNA severely inhibits the aerobic phosphorus uptake activity of PAOs. Although some studies have attempted to couple short-cut nitrification with EBPR, most have employed two-stage series reactors (separate EBPR reactors from short-cut nitrification / anaerobic ammonium oxidation reactors), and achieving long-term stable operation of both in the same reactor remains a significant challenge. Even the EBPR-PN process operating in the same reactor relies primarily on low DO control (0.2-1.5 mg / L) to maintain nitrite, and after long-term operation, AOB abundance decreases and system stability is insufficient. Existing technologies lack a complete and operable methodology, including: suitable carbon source preparation methods for coupled processes (such as the acquisition and control of SBOM fermentation broth), reactor operation control strategies (anaerobic / aerobic duration, SRT control, etc.), and operating parameters for PAOs to tolerate FNA, which has kept this technology in the laboratory exploration stage for a long time, making it difficult to translate into engineering applications.

[0004] Although another patent discloses a method for staged addition of sludge fermentation mixture to enhance dual short-range coupled anaerobic ammonium oxidation for deep nitrogen and phosphorus removal, utilizing the difference in inhibitory effects of the fermentation mixture on nitrifying bacteria to achieve partial short-range nitrification, the phosphorus content of fermentation broth from organic waste such as kitchen waste and excess sludge is as high as 50-200 mg / L. However, its drawback is that adding such fermentation broth as a supplementary carbon source for EBPR introduces an additional phosphorus load into the system. This not only interferes with the accurate assessment of the true phosphorus uptake performance of PAOs, but may also weaken the anaerobic phosphorus release efficiency of PAOs through feedback inhibition, thereby affecting the overall phosphorus removal effect of the system. The lack of systematic development and utilization of "phosphorus-free" fermentation broth carbon sources in existing technologies has become one of the key bottlenecks restricting the engineering application of fermentation broth carbon sources in EBPR. Summary of the Invention

[0005] To address the aforementioned technical problems, the purpose of this invention is to provide a system and method for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth. This invention utilizes zero-phosphorus starch fermentation broth, avoiding interference from phosphorus-containing carbon sources in traditional fermentation broths. The complex volatile fatty acids significantly enhance the metabolic activity of polyphosphate-accumulating bacteria and their tolerance to free nitrite. This allows for stable coupling of short-cut nitrification and efficient phosphorus removal in low-carbon-nitrogen ratio urban wastewater treatment. The raw materials for this invention are widely available, enabling the utilization of starch processing wastewater to achieve "waste-to-waste treatment," resulting in significant economic and environmental benefits and promising application prospects in the field of environmental microbiology.

[0006] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: The first objective of this invention is to provide a system for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth, comprising an inlet tank, an air pump, a microporous aeration disc, a sequencing batch reactor, an outlet tank, a starch fermentation tank, and a fermentation broth storage tank. The inlet tank, the sequencing batch reactor, and the outlet tank are connected in sequence; the starch fermentation tank, the fermentation broth storage tank, and the sequencing batch reactor are connected in sequence; the air pump is connected to the microporous aeration disc; and the microporous aeration disc is placed at the bottom of the sequencing batch reactor.

[0007] The beneficial effects of the present invention are: (1) The present invention uses starch processing wastewater or starch as raw material to prepare starch fermentation liquid, realizes the resource utilization of waste, conforms to the concept of circular economy, and reduces the cost of external carbon source; (2) The total phosphorus content of the starch fermentation broth is less than 0.01 mg / L, which is a zero-phosphorus carbon source, thus avoiding the interference caused by the phosphorus content of traditional fermentation broth carbon sources on the phosphorus removal performance evaluation. (3) Through long-term starch fermentation broth domestication, the inhibition threshold of PAOs on FNA is increased, and biological removal of phosphorus is achieved while achieving short-range nitrification.

[0008] Based on the above technical solution, the present invention can be further improved as follows.

[0009] Furthermore, the system also includes a gas flow meter, an inlet peristaltic pump, an outlet peristaltic pump, and a sludge pump; The sequencing batch reactor includes a stirring device, an inlet, an outlet, and a sludge inlet; The stirring device is installed inside the sequencing batch reactor. The tank of the sequencing batch reactor is provided with the water inlet, the sludge inlet, and the water outlet, and the water outlet is located below the sludge inlet. The outlet of the mud inlet pump is connected to the mud inlet, and the inlet of the mud inlet pump is connected to the outlet of the fermentation liquid storage tank; the outlet of the water outlet peristaltic pump is connected to the water outlet tank, and the inlet of the water outlet peristaltic pump is connected to the water outlet; the outlet of the water inlet peristaltic pump is connected to the water inlet, and the inlet of the water inlet peristaltic pump is connected to the outlet of the water inlet tank. The air pump is connected to the microporous aeration disc via the gas flow meter.

[0010] Furthermore, the system also includes a sludge pump; the starch fermentation tank includes a temperature controller, a fermentation stirring device, a fermentation heating rod, a feeding port, and a fermentation liquid discharge port; The fermentation stirring device and the fermentation heating rod are installed inside the starch fermentation tank; The starch fermentation tank has a feeding port on the top of the tank body, and a fermentation liquid outlet on the side wall of the tank body. The fermentation liquid outlet is connected to the inlet of the sludge pump, and the outlet of the sludge pump is connected to the inlet of the fermentation liquid storage tank. The temperature control instrument is located outside the starch fermentation tank and is electrically connected to the fermentation heating rod.

[0011] Furthermore, it also includes a monitoring component, which includes a WTW main unit, a dissolved oxygen monitoring probe, and a pH monitoring probe; the dissolved oxygen monitoring probe and the pH monitoring probe are disposed inside the sequencing batch reactor, and the WTW main unit is disposed outside the sequencing batch reactor and electrically connected to the dissolved oxygen monitoring probe.

[0012] The second objective of this invention is to provide a method for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth. This method is achieved through the aforementioned system for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth, and includes the following steps: S1. Start-up phase of the enhanced biological phosphorus removal (EBPR) process for actual domestic wastewater: The entire sludge from the actual wastewater treatment plant is directly inoculated into the sequencing batch reactor (SBR), achieving a sludge concentration of 3500-4000 mg / L. Domestic wastewater from the influent tank is transferred to the SBR. The SBR operates for 2-4 cycles per day, with the air pump adjusted to control the gas flow rate of the microporous aeration discs at 1.5-3.0 L / min, the pH maintained between 6.5-8.5, and the effluent ratio at 50-70%. Sodium acetate solution is added to the SBR from the fermentation broth storage tank during each cycle. The sludge retention time in the SBR is 8-12 days. Start-up is successful when the nitrate nitrogen yield in the effluent is higher than 10 mg / L, the nitrite content is lower than 1 mg / L, and the phosphorus removal efficiency is greater than 70%. S2. Preparation of starch fermentation broth: The starch mixture is continuously added to the starch fermentation tank for fermentation to obtain starch fermentation broth, and the starch fermentation broth is transported to the fermentation broth storage tank for later use. S3. Start-up and stable operation stage of short-cut nitrification achieved by adding starch fermentation broth to the EBPR process: The sequencing batch reactor maintains a constant cycle of 2-4 times per day. Domestic sewage in the influent tank is continuously transported to the sequencing batch reactor. The air pump is adjusted to control the gas flow rate of the microporous aeration disc to 1.5-3.0 L / min, the pH value is maintained between 6.5-8.5, the effluent ratio is 50-70%, the sludge retention time in the sequencing batch reactor is 8-12 days, and the starch fermentation broth is added to the sequencing batch reactor from the fermentation broth storage tank as an external carbon source. The cycle includes an influent phase of 0.1-0.2 h, an anaerobic mixing phase of 1.5-2.0 h, an aerobic aeration phase of 3.0-5.0 h, and a rest phase of 1.0-1.5 h. The sodium acetate solution mentioned in step S1 is added during the anaerobic stirring stage; The starch fermentation broth mentioned in step S3 is added during the anaerobic stirring stage.

[0013] The beneficial effects of this invention are as follows: This invention utilizes zero-phosphorus starch fermentation broth, avoiding interference from phosphorus-containing carbon sources in traditional fermentation broths. The complex volatile fatty acids significantly enhance the metabolic activity of polyphosphate-accumulating bacteria and their tolerance to free nitrite, enabling a stable coupling of short-cut nitrification and efficient phosphorus removal in low-carbon-nitrogen ratio urban wastewater treatment. The raw materials for this invention are widely available, allowing for the utilization of starch processing wastewater to achieve "waste-to-waste treatment," resulting in significant economic and environmental benefits and promising application prospects in the field of environmental microbiology.

[0014] Furthermore, the COD concentration of the sodium acetate solution in step S1 is 2000 mg COD / L, and the dosage in each cycle is 150-400 mL.

[0015] The beneficial effects of adopting the above-mentioned further scheme are: to provide stable and high-quality easily degradable carbon sources for polyphosphate-accumulating bacteria (PAOs), so as to precisely control and enhance the anaerobic phosphorus release and aerobic phosphorus uptake processes of the EBPR process.

[0016] Furthermore, in step S1, the influent is actual domestic sewage with a COD of 150-250 mg / L and ammonia nitrogen (NH4+). + The concentration of -N is 35-60 mg / L, and the C / N ratio is 3-4.

[0017] The beneficial effect of adopting the above-mentioned further scheme is that it extends the theoretically efficient coupling process to the practical feasibility, and verifies the stability, economy and robustness of the process under real, variable, and low carbon-nitrogen ratio water quality.

[0018] Furthermore, the concentration of the starch mixture in step S2 is 7.5-9.0 g / L, which translates to a COD of 8000-9770 mg; the starch mixture is formed by mixing starchy materials with water; the starchy materials are starch and / or starch processing wastewater; The starch is derived from at least one of corn, potato, cassava, wheat, and rice; the starch processing wastewater is at least one of corn starch processing wastewater, potato starch processing wastewater, cassava starch processing wastewater, and wheat starch processing wastewater; when the starchy material is the starch processing wastewater, the COD concentration is 6000 mg / L-30000 mg / L.

[0019] The beneficial effects of adopting the above-mentioned further solutions are: the raw materials are widely available, waste resources are utilized, and the concept of circular economy is in line with the requirements of circular economy.

[0020] Furthermore, in step S2, the fermentation temperature is 35±1℃, the stirring speed is 150-300 rpm, and the residence time of the starch mixture is 6-8 days.

[0021] The beneficial effects of adopting the above-mentioned further scheme are: the temperature can maximize the activity of hydrolytic acidifying enzymes, rapidly converting starch into high concentrations of VFAs, while controlling the SRT to 6-8 days can effectively eliminate methanogenic bacteria with longer generations, allowing fermentation to remain stably in the acid-producing stage and preventing VFAs from being further converted into methane.

[0022] Furthermore, the volatile fatty acids in the starch fermentation broth account for 53.65% of the total COD, with acetic acid, propionic acid, and butyric acid being the main components, and the total phosphorus content is less than 0.01 mg / L.

[0023] Furthermore, the amount of starch fermentation broth added in each cycle in step S3 is 150 mL to 300 mL.

[0024] The beneficial effects of adopting the above-mentioned further scheme are: by using a low-cost carbon source (starch fermentation broth), the optimal configuration of fast and slow carbon sources is achieved, which further improves phosphorus removal stability and total nitrogen removal rate without affecting autotrophic denitrification, and significantly reduces operating costs, while strengthening the system's resilience against water quality fluctuations. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the device structure according to Embodiment 1 of the present invention; Figure 2 This is a graph showing the total production of volatile fatty acids in a starch fermentation tank over a long period of time. Figure 3 This is a graph showing the changes of various indicators over time during the start-up and stabilization of a short-path nitrification coupled enhanced biological phosphorus removal process using a sequencing batch reactor (SBR). Figure 4 This is a graph showing the tolerance of sludge acclimated from fermentation broth to FNA inhibition compared to ordinary biological phosphorus removal sludge.

[0026] The attached diagram lists the components represented by each number as follows: 1. Water inlet tank; 2. Water inlet peristaltic pump; 3. Air pump; 3-1. Gas flow meter; 3-2. Microporous aeration disc; 4. Sequencing batch reactor; 4-1. Stirring device; 4-2. Water inlet; 4-3. Water outlet; 4-4. Sludge inlet; 4-5. Water outlet peristaltic pump; 4-6. Water outlet tank; 5. WTW main unit; 5-1. Dissolved oxygen monitoring probe; 5-2. pH monitoring probe; 6. Starch fermentation tank; 6-1. Fermentation broth outlet; 6-2. Feeding port; 6-3. Fermentation broth storage tank; 6-4. Fermentation stirring device; 6-5. Temperature control instrument; 6-6. Fermentation heating rod; 6-7. Sludge discharge pump; 6-8. Sludge inlet pump. Detailed Implementation

[0027] The principles and features of the present invention are described below. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0028] Example 1: This Example 1 describes a system that couples short-cut nitrification with enhanced biological phosphorus removal using starch fermentation broth. Figure 1 As shown, the details are as follows: A short-cut nitrification and enhanced biological phosphorus removal system coupled with starch fermentation broth is used, including an inlet tank 1, an air pump 3, microporous aeration discs 3-2, a sequencing batch reactor 4, an outlet tank 4-6, a starch fermentation tank 6, and a fermentation broth storage tank 6-3. The inlet tank 1, the sequencing batch reactor 4, and the outlet tank 4-6 are connected in sequence; the starch fermentation tank 6, the fermentation liquid storage tank 6-3, and the sequencing batch reactor 4 are connected in sequence; the air pump 3 is connected to the microporous aeration disc 3-2; the microporous aeration disc 3-2 is placed at the bottom of the sequencing batch reactor 4.

[0029] Preferably, the system also includes a gas flow meter 3-1, an inlet peristaltic pump 2, an outlet peristaltic pump 4-5, and a sludge pump 6-8; The sequencing batch reactor 4 includes a stirring device 4-1, an inlet 4-2, an outlet 4-3, and a sludge inlet 4-4; A stirring device 4-1 is installed inside the sequencing batch reactor 4. The tank body of the sequencing batch reactor 4 is provided with an inlet 4-2, a sludge inlet 4-4, and an outlet 4-3, with the outlet 4-3 located below the sludge inlet 4-4. The outlet of the mud inlet pump 6-8 is connected to the mud inlet 4-4, and the inlet of the mud inlet pump 6-8 is connected to the outlet of the fermentation broth storage tank 6-3; the outlet of the water outlet peristaltic pump 4-5 is connected to the water outlet tank 4-6, and the inlet of the water outlet peristaltic pump 4-5 is connected to the water outlet 4-3; the outlet of the water inlet peristaltic pump 2 is connected to the water inlet 4-2, and the inlet of the water inlet peristaltic pump 2 is connected to the outlet of the water inlet tank 1. The air pump 3 is connected to the microporous aeration disc 3-2 via the gas flow meter 3-1.

[0030] Preferably, the system also includes a sludge pump 6-7; the starch fermentation tank 6 includes a temperature control instrument 6-5, a fermentation stirring device 6-4, a fermentation heating rod 6-6, a feeding port 6-2, and a fermentation liquid discharge port 6-1; Fermentation stirring device 6-4 and fermentation heating rod 6-6 are installed inside starch fermentation tank 6; The starch fermentation tank 6 has a feeding port 6-2 on the top of the tank body, and a fermentation liquid outlet 6-1 on the side wall of the tank body. The fermentation liquid outlet 6-1 is connected to the inlet of the sludge pump 6-7, and the outlet of the sludge pump 6-7 is connected to the inlet of the fermentation liquid storage tank 6-3. The temperature control instrument 6-5 is set outside the starch fermentation tank and is electrically connected to the fermentation heating rod 6-6.

[0031] Preferably, it also includes a monitoring component, which includes a WTW main unit 5, a dissolved oxygen monitoring probe 5-1, and a pH monitoring probe 5-2; the dissolved oxygen monitoring probe 5-1 and the pH monitoring probe 5-2 are disposed inside the sequencing batch reactor 4, and the WTW main unit 5 is disposed outside the sequencing batch reactor 4 and is electrically connected to the dissolved oxygen monitoring probe 5-1.

[0032] Example 2: This invention discloses a method for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth, comprising the following specific steps: S1. Start-up of the enhanced biological phosphorus removal (EBPR) process for actual domestic wastewater: The sludge from the Gaobeidian Wastewater Treatment Plant in Beijing was directly inoculated into the sequencing batch reactor 4. After the sludge inoculation was completed, the sludge concentration in the reactor was maintained at 3500 mg / L, the effective volume of the reactor was 7.5 L, and the volume exchange rate was 50%. Dissolved oxygen monitoring probe 5-1 and pH monitoring probe 5-2 are immersed below the liquid surface of the sequencing batch reactor 4. The dissolved oxygen monitoring probe 5-1 and pH monitoring probe 5-2 sense the pH and dissolved oxygen content of the mixed system in the sequencing batch reactor 4 in real time, and each outputs the corresponding electrical signal to the WTW host 5. The pH of the mixed system in the sequencing batch reactor 4 is maintained at 7.0 in real time by monitoring and reading the pH. The gas pump 3 is adjusted according to the gas flow meter 3-1 to control the gas flow rate of the microporous aeration disc 3-2 at 2.0 L / min. The influent is actual domestic sewage, with COD of 150-250 mg / L and ammonia nitrogen (NH4) content of [missing information]. + -N): 35-60 mg / L, C / N ratio is 3-4, and the domestic sewage in the inlet tank 1 is first pumped into the sequencing batch reactor 4 from the inlet 4-2 by the inlet peristaltic pump 2; The sequencing batch reactor 4 operates for two cycles per day, including 10 minutes of influent, 2.0 hours of anaerobic agitation using the stirring device 4-1, 3.0 hours of aerobic agitation, and 3.0 hours of idle time. The gas flow rate of the microporous aeration disc 3-2 is controlled at 2.0 L / min by adjusting the gas pump 3 according to the gas flow meter 3-1, maintaining the pH at 7.0, and the effluent ratio at 50%. The peristaltic pump 4-5 pumps the phosphorus-removed water from the outlet 4-3 of the sequencing batch reactor 4 to the outlet tank 4-6. During the anaerobic agitation stage of each cycle, the sludge pump 6-8 uses a sodium acetate solution with a COD concentration of 2000 mg COD / L from the fermentation broth storage tank 6-3 as an external carbon source, pumping 150 ml / min per cycle through the sludge inlet 4-4. mL of sludge was added to the sequencing batch reactor 4. The sludge in the sequencing batch reactor 4 was discharged daily to maintain a sludge retention time of 12 days. The system operated in the anaerobic / aerobic alternating (A / O) mode for a long time. The nitrate nitrogen production in the effluent was higher than 15 mg / L and there was no nitrite accumulation. The phosphorus removal efficiency was greater than 80%. The enhanced biological phosphorus removal process for domestic sewage was successfully started in the sequencing batch reactor 4.

[0033] S2. Preparation of starch fermentation broth: Starch fermentation broth was prepared using corn starch (analytical grade) as raw material and a semi-continuous flow anaerobic fermentation process. The starch was mixed with water to prepare a starch mixture. The starch concentration in the starch mixture was 8.35 g / L, and the COD was 8906 mg / L. 400 mL of starch mixture is continuously added into the 2.8 L starch fermentation tank 6 through the feeding port 6-2. The fermentation stirring device 6-4, temperature control instrument 6-5, and fermentation heating rod 6-6 are started to make the starch fermentation tank 6 operate at 35℃ and stirring speed 200 rpm. The residence time of the starch mixture is 7 days. Every day, the same volume of starch fermentation liquid as the added amount (i.e., 400 mL) is discharged from the fermentation liquid outlet 6-1 and pumped into the fermentation liquid storage tank 6-3 for later use through the sludge pump 6-7. The pH is not manually adjusted. The starch fermentation broth contains 53.65% volatile fatty acids in total COD, with acetic acid, propionic acid, and butyric acid as the main components. When the total phosphorus content is less than 0.01 mg / L, the starch fermentation broth is obtained. S3. Starch fermentation broth is added to the EBPR process to achieve short-cut nitrification start-up and stable operation: After the enhanced biological phosphorus removal process is successfully started, the sequencing batch reactor 4 continues to operate on two cycles per day, including 10 minutes of influent, 2.0 hours of anaerobic stirring, 3.0 hours of aerobic aeration and stirring, and 3.0 hours of idle time. The gas pump 3 is adjusted according to the gas flow meter 3-1 to control the gas flow rate of the microporous aeration disc 3-2 to 2.0 L / min, the pH value is maintained at 7.0, and the effluent ratio is 50%. The sequencing batch reactor discharges sludge every day to maintain the sludge retention time in the reactor at 12 days. Sodium acetate is no longer added as an external carbon source. The starch fermentation broth in the fermentation broth storage tank 6-3 is used as an external carbon source and pumped into the sequencing batch reactor 4 at a rate of 250 mL per cycle through the sludge inlet 4-4 using the sludge pump 6-8. The influent is actual domestic sewage, with COD of 150-250 mg / L and NH4+. + -N: 35-60 mg / L, C / N is 3-4. The domestic sewage in the inlet tank 1 is first pumped into the sequencing batch reactor 4 by the inlet peristaltic pump 2. Sludge is discharged daily from the inlet 4-4, controlling the sludge retention time (SRT) in the sequencing batch reactor to 12 days, with a non-aggregate air removal rate (NAR) exceeding 80% and maintained stably for over 30 days, while phosphorus removal efficiency remains above 80%. Figures 2-4 As shown, short-cut nitrification was successfully achieved in the enhanced biological phosphorus removal process.

[0034] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0035] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0036] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "over," and "on top" of the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0037] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A system for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth, characterized in that: Includes an inlet tank (1), an air pump (3), a microporous aeration disc (3-2), a sequencing batch reactor (4), an outlet tank (4-6), a starch fermentation tank (6), and a fermentation liquid storage tank (6-3). The inlet tank (1), the sequencing batch reactor (4), and the outlet tank (4-6) are connected in sequence; the starch fermentation tank (6), the fermentation liquid storage tank (6-3), and the sequencing batch reactor (4) are connected in sequence; the air pump (3) is connected to the microporous aeration disc (3-2); the microporous aeration disc (3-2) is placed at the bottom of the sequencing batch reactor (4).

2. The starch fermentation broth coupled with short-cut nitrification and enhanced biological phosphorus removal system according to claim 1, characterized in that, The system also includes a gas flow meter (3-1), an inlet peristaltic pump (2), an outlet peristaltic pump (4-5), and a sludge pump (6-8). The sequencing batch reactor (4) includes a stirring device (4-1), an inlet (4-2), an outlet (4-3), and a sludge inlet (4-4). The stirring device (4-1) is installed inside the sequencing batch reactor (4). The tank body of the sequencing batch reactor (4) is provided with the water inlet (4-2), the sludge inlet (4-4), and the water outlet (4-3), and the water outlet (4-3) is located below the sludge inlet (4-4). The outlet of the mud inlet pump (6-8) is connected to the mud inlet (4-4), and the inlet of the mud inlet pump (6-8) is connected to the outlet of the fermentation liquid storage tank (6-3); the outlet of the water outlet peristaltic pump (4-5) is connected to the water outlet tank (4-6), and the inlet of the water outlet peristaltic pump (4-5) is connected to the water outlet (4-3); the outlet of the water inlet peristaltic pump (2) is connected to the water inlet (4-2), and the inlet of the water inlet peristaltic pump (2) is connected to the outlet of the water inlet tank (1); The air pump (3) is connected to the microporous aeration disc (3-2) via the gas flow meter (3-1).

3. The starch fermentation broth coupled with short-cut nitrification and enhanced biological phosphorus removal system according to claim 1, characterized in that, The system also includes a sludge pump (6-7); the starch fermentation tank (6) includes a temperature controller (6-5), a fermentation stirring device (6-4), a fermentation heating rod (6-6), a feeding port (6-2), and a fermentation liquid discharge port (6-1). The fermentation stirring device (6-4) and the fermentation heating rod (6-6) are installed inside the starch fermentation tank (6); The starch fermentation tank (6) has a feeding port (6-2) on the top of the tank body, and a fermentation liquid outlet (6-1) on the side wall of the tank body. The fermentation liquid outlet (6-1) is connected to the inlet of the sludge pump (6-7), and the outlet of the sludge pump (6-7) is connected to the inlet of the fermentation liquid storage tank (6-3). The temperature control instrument (6-5) is located outside the starch fermentation tank and is electrically connected to the fermentation heating rod (6-6).

4. The starch fermentation broth coupled with short-cut nitrification and enhanced biological phosphorus removal system according to claim 1, characterized in that, It also includes a monitoring component, which includes a WTW host (5), a dissolved oxygen monitoring probe (5-1), and a pH monitoring probe (5-2); the dissolved oxygen monitoring probe (5-1) and the pH monitoring probe (5-2) are located inside the sequencing batch reactor (4), and the WTW host (5) is located outside the sequencing batch reactor (4) and is electrically connected to the dissolved oxygen monitoring probe (5-1).

5. A method for coupling short-cut nitrification with enhanced biological phosphorus removal using starch fermentation broth, characterized in that: The system described in any one of claims 1 to 4, which utilizes starch fermentation broth coupled with short-cut nitrification and enhanced biological phosphorus removal, includes the following steps: S1. Start-up stage of the enhanced biological phosphorus removal process for actual domestic sewage: The sludge from the actual sewage treatment plant is directly inoculated into the sequencing batch reactor (4) to make the sludge concentration in the sequencing batch reactor (4) 3500-4000 mg / L; the domestic sewage in the inlet tank (1) is transported to the sequencing batch reactor (4); the sequencing batch reactor (4) runs for 2-4 cycles per day, and the air pump (3) is adjusted to control the gas flow rate of the microporous aeration disc (3-2) to be 1.5-3.0 L / min, the pH value is maintained between 6.5-8.5, the effluent ratio is 50-70%, and sodium acetate solution is added to the sequencing batch reactor (4) in the fermentation broth storage tank (6-3) in each cycle. The sludge retention time in the sequencing batch reactor (4) is 8-12 days. When the nitrate nitrogen production in the effluent is higher than 10 mg / L and the nitrite content is lower than 1 mg / L, and the phosphorus removal efficiency is greater than 70%, the start-up is successful. S2. Preparation of starch fermentation broth: The starch mixture is continuously added to the starch fermentation tank (6) to obtain starch fermentation liquid, and the starch fermentation liquid is transported to the fermentation liquid storage tank (6-3) for later use; S3. Start-up and stable operation stage of short-cut nitrification achieved by adding starch fermentation liquid to the enhanced biological phosphorus removal system: The sequencing batch reactor (4) maintains 2-4 cycles per day. Domestic sewage in the inlet tank (1) is continuously transported to the sequencing batch reactor (4). The air pump (3) is adjusted to control the gas flow rate of the microporous aeration disc (3-2) to be 1.5-3.0 L / min, the pH value is maintained between 6.5-8.5, the drainage ratio is 50-70%, the sludge retention time in the sequencing batch reactor (4) is 8-12 days, and the starch fermentation liquid is added to the sequencing batch reactor (4) as an external carbon source in the fermentation liquid storage tank (6-3). The cycle includes an influent phase of 0.1-0.2 h, an anaerobic mixing phase of 1.5-2.0 h, an aerobic aeration phase of 3.0-5.0 h, and a rest phase of 1.0-1.5 h. The sodium acetate solution mentioned in step S1 is added during the anaerobic stirring stage; The starch fermentation broth mentioned in step S3 is added during the anaerobic stirring stage.

6. The method for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth according to claim 5, characterized in that, The COD concentration of the sodium acetate solution in step S1 is 2000 mg COD / L, and the dosage in each cycle is 150 mL to 400 mL.

7. The method for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth according to claim 5, characterized in that, In step S1, the influent is actual domestic sewage with a COD of 150-250 mg / L, ammonia nitrogen of 35-60 mg / L, and a carbon-to-nitrogen ratio of 3-4.

8. The method for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth according to claim 5, characterized in that, The concentration of the starch mixture in step S2 is 7.5-9.0 g / L; the starch mixture is formed by mixing starchy materials with water; the starchy materials are starch or starch processing wastewater; The starch is derived from at least one of corn, potato, cassava, wheat, and rice; the starch processing wastewater is at least one of corn starch processing wastewater, potato starch processing wastewater, cassava starch processing wastewater, and wheat starch processing wastewater; when the starchy material is the starch processing wastewater, the COD concentration is 6000 mg / L-30000 mg / L.

9. The method for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth according to claim 5, characterized in that, The fermentation temperature in step S2 is 35±1℃, the stirring speed is 150-300 rpm, and the residence time of the starch mixture is 6-8 days.

10. The method for coupling short-cut nitrification and enhanced biological phosphorus removal using starch fermentation broth according to claim 7, characterized in that, The amount of starch fermentation broth added in each cycle in step S3 is 150 mL to 300 mL.

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