Direct-current intensified AAO biological reaction device with built-in pyrite filler

Abstract

The invention discloses a direct current enhanced AAO biological reaction device with built-in pyrite filler, and relates to the technical field of sewage treatment. The device comprises a water inlet system, an AAO bioreactor, a mud-water separation system and a direct-current power supply, the AAO bioreactor comprises an anaerobic zone, an anoxic zone and an aerobic zone, and the anoxic zone and the aerobic zone are filled with pyrite filler and carbon brushes; the water inlet system is connected with the anaerobic zone and is used for feeding sewage into the AAO bioreactor; the sludge-water separation system is connected with the aerobic zone and is used for returning sludge to the anaerobic zone; the cathode and the anode of the direct-current power supply are connected with the brush handle of the carbon brush. By applying direct current, the electron transfer process of microorganisms is accelerated, and the nitrogen and phosphorus removal efficiency is improved. And by adding the carbon brush and the pyrite filler, the impact load resistance of the system is improved, and the generation of sludge is reduced. And nitrogen and phosphorus removal is realized without additional carbon sources and chemical agents, so that the cost is saved.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a DC-powered AAO bioreactor with built-in pyrite packing. Background Technology

[0002] The concentration of carbon sources in existing urban wastewater influent shows a gradual downward trend, while the concentrations of nitrogen and phosphorus nutrients are increasing. The ratio of chemical oxygen demand (COD) to total phosphorus (TP) and total nitrogen (TN) is gradually decreasing, and traditional biological nitrogen and phosphorus removal processes face multiple technical bottlenecks. Urban wastewater is characterized by a low C / N ratio (COD / TN < 5), and insufficient carbon sources lead to low denitrification efficiency, requiring the addition of large amounts of organic carbon sources such as methanol. This not only increases operating costs by 30% to 50%, but also, after biochemical reactions, these carbon sources are converted into CO2 and released into the atmosphere, making wastewater treatment plants a significant source of fossil carbon emissions. Extensive practical experience shows that when the TP concentration in the influent of a wastewater treatment plant is greater than 4-5 mg / L and the m(BOD5) / m(TKN) ratio is less than 5-8, traditional biological treatment methods can hardly guarantee the removal of phosphorus and nitrogen. Carbon source is a necessary factor for nitrogen and phosphorus removal. The reduction of carbon source severely restricts the nitrogen and phosphorus removal effect of urban wastewater, making it difficult for urban wastewater to fully remove nitrogen and phosphorus by relying solely on the influent carbon source. Instead, it requires the consumption of a large amount of carbon source and chemical flocculants to assist in the treatment, resulting in a large waste of resources and carbon emissions.

[0003] Anaerobic-anoxic-aerobic bioreactor (AAO) is a wastewater treatment process that integrates anaerobic phosphorus release, denitrification, and aerobic phosphorus uptake, and is widely used in the field of biological nitrogen and phosphorus removal. However, when treating low C / N municipal wastewater, the AAO process is limited by insufficient carbon sources, intensified competition for carbon sources within the system, and significant inhibition of denitrification and biological phosphorus removal processes, resulting in decreased nitrogen and phosphorus removal efficiency and difficulty in ensuring operational stability. Summary of the Invention

[0004] The purpose of this invention is to provide a DC-enhanced AAO bioreactor with built-in pyrite packing, which aims to solve or improve at least one of the above-mentioned technical problems.

[0005] To achieve the above objectives, the present invention provides the following solution: A DC-powered, internally packed pyrite-filled AAO bioreactor includes: Inlet system, AAO bioreactor, sludge-water separation system and DC power supply; The AAO bioreactor consists of an anaerobic zone, an anoxic zone, and an aerobic zone. The anoxic and aerobic zones are filled with pyrite packing and carbon brushes. The influent system is connected to the anaerobic zone and is used to send wastewater into the AAO bioreactor; The sludge-water separation system is connected to the aerobic zone and is used to return sludge to the anaerobic zone; Both the cathode and anode of the DC power supply are connected to the brush handle of the carbon brush.

[0006] Furthermore, the water inlet system includes an inlet tank and an inlet pump; Wastewater in the influent system is connected to the anaerobic zone of the AAO reactor via an influent pump in the influent tank.

[0007] Furthermore, the AAO bioreactor also includes: agitator, aeration stone, rotor flow meter, aeration pump, guide plate and internal reflux pump; The AAO bioreactor is divided into anaerobic, anoxic, and aerobic zones by a flow guide plate. The stirrer is placed in the anaerobic zone and the anoxic zone; The two ends of the internal reflux pump are connected to the anoxic zone and the aerobic zone, respectively; The aeration pump is connected to the aerobic zone via a rotor flow meter and aeration stones to supply oxygen to the aerobic zone.

[0008] Furthermore, the sludge-water separation system includes a secondary sedimentation tank and a sludge return pump; One end of the secondary sedimentation tank is connected to the aerobic zone, and the other end is connected to the sludge return pump.

[0009] Furthermore, the volume ratio of the anaerobic zone, the anoxic zone, and the aerobic zone is 1:2:4.

[0010] Furthermore, the anoxic zone and the aerobic zone are filled with 600g and 1000g of pyrite filler, respectively; the pyrite filler has a particle size of 5-8mm.

[0011] Furthermore, the hydraulic retention time of the AAO bioreactor is 18 hours.

[0012] Furthermore, the internal reflux ratio of the AAO bioreactor is 150%.

[0013] Furthermore, the AAO bioreactor has a length, width, and height of 79cm, 15cm, and 20cm, respectively, and an effective volume of 14L.

[0014] Furthermore, one carbon brush is placed in the hypoxic zone and one in the aerobic zone.

[0015] According to specific embodiments provided by the present invention, the present invention discloses the following technical effects: This invention discloses a DC-enhanced AAO bioreactor with built-in pyrite packing. The device accelerates the electron transfer process of microorganisms by applying DC current, thereby improving the efficiency of nitrogen and phosphorus removal. The addition of carbon brushes and pyrite packing enhances the system's resistance to shock loads and reduces sludge production. Furthermore, nitrogen and phosphorus removal can be achieved without the need for external carbon sources and chemical agents, saving costs. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the structural composition of the device of the present invention; In the diagram, 1. Inlet system; 2. AAO bioreactor; 3. Sludge-water separation system; 4. DC power supply; 1.1 Wastewater inlet tank; 1.2 Inlet pump; 2.1 Anaerobic zone; 2.2 Anoxic zone; 2.3 Aerobic zone; 2.4 Agitator; 2.5 Carbon brush; 2.6 Aeration stone; 2.7 Rotor flow meter; 2.8 Aeration pump; 2.9 Baffle plate; 2.10 Pyrite packing; 2.11 Internal return pump; 3.1 Secondary sedimentation tank; 3.2 Sludge return pump. Detailed Implementation

[0018] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0019] The purpose of this invention is to provide a DC-enhanced AAO bioreactor with built-in pyrite packing, which aims to solve or improve at least one of the above-mentioned technical problems.

[0020] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0021] like Figure 1 As shown, this invention provides a DC-enhanced AAO bioreactor with built-in pyrite packing, comprising: 1. Inlet system; 2. AAO bioreactor; 3. Sludge-water separation system; 4. DC power supply; The water inlet system 1 includes: a water inlet tank 1.1 and a water inlet pump 1.2; The AAO bioreactor 2 comprises: an anaerobic zone 2.1, an anoxic zone 2.2, an aerobic zone 2.3, a stirrer 2.4, a carbon brush 2.5, an aeration stone 2.6, a rotor flowmeter 2.7, an aeration pump 2.8, a baffle plate 2.9, pyrite packing material 2.10, and an internal reflux pump 2.11. The preferred length, width, and height of the AAO bioreactor 2 are 79 cm, 15 cm, and 20 cm, respectively, with an effective volume of 14 L. The hydraulic retention time is controlled at 18 h. The volume ratio of the anaerobic zone 2.1, the anoxic zone 2.2, and the aerobic zone 2.3 is 1:2:4; the internal reflux ratio is 150%. The sludge-water separation system 3 includes: a secondary sedimentation tank 3.1 and a sludge return pump 3.2.

[0022] Wastewater in the inlet system 1 is connected to the anaerobic zone 2.1 of the AAO reactor 2 via the inlet tank 1.1 and the inlet pump 1.2; Anaerobic zone 2.1, anoxic zone 2.2, and aerobic zone 2.3 are sequentially arranged via guide plates 2.9. The two ends of the internal return pump 2.11 are connected to anoxic zone 2.2 and aerobic zone 2.3 respectively, returning wastewater from aerobic zone 2.3 to anoxic zone 2.2. Both anaerobic zone 2.1 and anoxic zone 2.2 are equipped with agitators 2.4. Anoxic zone 2.2 and aerobic zone 2.3 are filled with 5-8mm pyrite filler 2.10 and carbon brushes 2.5. Anoxic zone 2.2 is filled with 600g of pyrite filler 2.10 and 4 carbon brushes 2.5; aerobic zone 2.3 is filled with 1000g of pyrite filler 2.10 and 6 carbon brushes 2.5. Pyrite filler 2.10 is uniformly filled in the lower layer of the anoxic zone 2.2 and the aerobic zone 2.3 and connected to the carbon brush 2.5; the carbon brush 2.5 has a diameter of 4.5cm and a length of 15cm; The anoxic zone 2.3 is connected to the secondary sedimentation tank 3.1 of the mud-water separation system 3; The secondary sedimentation tank 3.1 is connected to the anaerobic zone 2.1 via a sludge return pump 3.2, which is used to return the sludge in the secondary sedimentation tank 3.1 to the anaerobic zone 2.1; the sludge in the secondary sedimentation tank 3.1 is periodically discharged from the sludge discharge pipe. Aeration pump 2.8 is connected to aerobic zone 2.3 via rotor flow meter 2.7 and aeration stone 2.6 to supply oxygen to aerobic zone 2.3; Both the cathode and anode of the DC power supply 4 are connected to the brush handle of the carbon brush 2.5. The DC power supply 4 is preferably an APS3005S-3D. The DC power supply 4 is preferably supplied with 0.6V / 0.9V / 1.2V DC.

[0023] In the device of the present invention, wastewater enters the reactor from the anaerobic zone 2.1 and flows sequentially into the anoxic zone 2.2 and the aerobic zone 2.3 to achieve nitrogen and phosphorus removal.

[0024] To verify the effectiveness of the device of the present invention, four types of reactors were designed as shown in Table 1.

[0025] Table 1 Design of four reactors

[0026] As shown in Table 2, the removal rates of different pollutants by four different reactors were obtained through experiments.

[0027] Table 2. Different pollutant removal rates of four reactors

[0028] A comparison of the pollutant removal efficiency of the four reactors shows that R3 is the best performing reactor, achieving the highest TP (57.68%) and NH4+ removal rates. + -N (96.89%) and TN (93.38%) removal rates were at the highest levels, while TP and NH4+ removal rates were lower. + Compared to R1, the removal rates of -N and TN increased by 13.26%, 34.61%, and 36.29%, respectively; compared to R2, they increased by 26.09%, 25.35%, and 25.68%, respectively; and compared to R4, the removal rates of TP and NH4 were comparable. + -N and TN increased by 8.27% and 4.76%, respectively. This indicates that DC-enhanced AAO bioreactors with built-in pyrite packing can increase TP and NH4+. + The removal effect of -N and TN.

[0029] By adding Fe2+ and elemental sulfur (S) contained in pyrite filler itself 0 Using sulfide ions (S2-) as electron donors, nitrate nitrogen (NO3-) in water is directly reduced to nitrogen gas (N2), achieving highly efficient denitrification. No external organic carbon source needs to be added during the process, which not only reduces operating costs but also effectively avoids secondary pollution problems caused by carbon source addition. Simultaneously, the system's sludge production rate is reduced by approximately 40%-60%, decreasing the burden of treating excess sludge. Furthermore, sulfate (SO42-) in the water can be removed simultaneously, enhancing the sulfur cycle while achieving denitrification. In addition, FeS2 can be oxidized to generate Fe3+, which further reacts with PO43- to form FePO4 precipitate, improving phosphorus removal efficiency.

[0030] By connecting an external DC power supply 4, in nitrogen and phosphorus removal applications, the external electric field can significantly enhance electron transfer between microorganisms, improve microbial metabolic activity, optimize the structure of functional bacterial communities, and promote the enrichment of nitrogen and phosphorus removal functional microorganisms, thereby effectively improving the system's removal efficiency of nitrogen and phosphorus pollutants. Simultaneously, DC power can accelerate the electron transfer process of microorganisms and effectively promote the dissolution of pyrite packing, enhancing the system's simultaneous nitrogen and phosphorus removal efficiency.

[0031] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0032] This document uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the core ideas of the present invention. Furthermore, those skilled in the art will recognize that, based on the ideas of the present invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of the present invention.

Claims

1. A DC-enhanced AAO bioreactor with built-in pyrite packing, characterized in that, include: Water inlet system (1), AAO bioreactor (2), mud-water separation system (3) and DC power supply (4); The AAO bioreactor (2) includes an anaerobic zone (2.1), an anoxic zone (2.2) and an aerobic zone (2.3), and the anoxic zone (2.2) and the aerobic zone (2.3) are filled with pyrite packing material (2.10) and carbon brushes (2.5). The influent system (1) is connected to the anaerobic zone (2.1) to deliver wastewater into the AAO bioreactor (2); The sludge-water separation system (3) is connected to the aerobic zone (2.3) to return sludge to the anaerobic zone (2.1). The cathode and anode of the DC power supply (4) are both connected to the brush handle of the carbon brush (2.5).

2. The DC-enhanced AAO bioreactor with built-in pyrite packing as described in claim 1, characterized in that, The water inlet system (1) includes a water inlet tank (1.1) and a water inlet pump (1.2). Wastewater in the inlet system (1) is connected to the anaerobic zone (2.1) of the AAO reactor (2) via the inlet tank (1.1) and the inlet pump (1.2).

3. The DC-enhanced AAO bioreactor with built-in pyrite packing as described in claim 1, characterized in that, The AAO bioreactor (2) also includes: a stirrer (2.4), an aeration stone (2.6), a rotor flow meter (2.7), an aeration pump (2.8), a guide plate (2.9), and an internal reflux pump (2.11). The AAO bioreactor (2) is divided into an anaerobic zone (2.1), an anoxic zone (2.2), and an aerobic zone (2.3) by a flow guide plate (2.9). A stirrer (2.4) is placed in the anaerobic zone (2.1) and the anoxic zone (2.2); The two ends of the internal reflux pump (2.11) are connected to the anoxic zone (2.2) and the aerobic zone (2.3), respectively; The aeration pump (2.8) is connected to the aerobic zone (2.3) via a rotor flow meter (2.7) and aeration stone (2.6) to supply oxygen to the aerobic zone (2.3).

4. The DC-enhanced AAO bioreactor with built-in pyrite packing as described in claim 1, characterized in that, The sludge-water separation system (3) includes a secondary sedimentation tank (3.1) and a sludge return pump (3.2). The secondary sedimentation tank (3.1) is connected to the aerobic zone (2.3) at one end and to the sludge return pump (3.2) at the other end.

5. The DC-enhanced AAO bioreactor with built-in pyrite packing as described in claim 1, characterized in that, The volume ratio of the anaerobic zone (2.1), the anoxic zone (2.2), and the aerobic zone (2.3) is 1:2:

4.

6. The DC-enhanced AAO bioreactor with built-in pyrite packing as described in claim 1, characterized in that, The anoxic zone (2.2) and the aerobic zone (2.3) are respectively filled with 600g and 1000g of pyrite filler (2.10); the pyrite filler (2.10) has a particle size of 5-8mm.

7. The DC-enhanced AAO bioreactor with built-in pyrite packing as described in claim 1, characterized in that, The hydraulic retention time of the AAO bioreactor (2) is 18h.

8. The DC-enhanced AAO bioreactor with built-in pyrite packing as described in claim 1, characterized in that, The internal reflux ratio of the AAO bioreactor (2) is 150%.

9. A DC-enhanced AAO bioreactor with built-in pyrite packing as described in claim 1, characterized in that, The length, width and height of the AAO bioreactor (2) are 79cm, 15cm and 20cm respectively, and the effective volume is 14L.

10. A DC-enhanced AAO bioreactor with built-in pyrite packing according to claim 1, characterized in that, Four carbon brushes (2.5) are placed in the anoxic zone (2.2) and six carbon brushes (2.3).

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