A combined SBR and PDA-based urban wastewater treatment device and method

Abstract

This invention discloses a combined SBR (Self-Breakthrough Bioreactor) and PDA (Protective Anaerobic Dioxide) device and method for treating urban wastewater. The device includes a PDA unit comprising an anaerobic zone, an anoxic zone, an anaerobic ammonia oxidation zone, and a secondary sedimentation tank. The secondary sedimentation tank is connected to the anaerobic zone via a sludge return pump. The output of the aerobic granular sludge SBR unit is connected to the anoxic zone of the PDA unit via an intermediate water tank. The effluent from the secondary sedimentation tank is connected to the input of the aerobic granular sludge SBR unit via an effluent return pump. The output of the raw urban wastewater tank is connected to both the input of the aerobic granular sludge SBR unit and the anaerobic zone of the PDA unit. This device divides urban wastewater into two parts, which enter the aerobic granular sludge SBR unit and the PDA unit. The former provides effluent for the latter, and the two are cleverly combined and complement each other. Utilizing short-cut denitrification coupled with anaerobic ammonia oxidation technology to treat high-concentration nitrate nitrogen effluent has significant practical implications.

Description

Technical Field

[0001] This invention belongs to the field of urban wastewater treatment technology, and more specifically, relates to an SBR combined with a side-by-side PDA urban wastewater treatment device and method. Background Technology

[0002] In recent years, compliance with emission standards at urban wastewater treatment plants has received considerable attention, especially with increasingly stringent controls on effluent nitrogen and phosphorus concentrations. Most urban wastewater treatment plants in my country still employ traditional nitrification-denitrification processes. These plants generally have low influent C / N ratios, and the limited organic matter is insufficient to effectively remove nitrogenous pollutants from the wastewater. This typically necessitates the use of additional organic carbon sources to achieve effluent quality standards, thereby increasing investment and operating costs.

[0003] To date, aerobic granular sludge technology is considered one of the most promising biological wastewater treatment technologies. It has many advantages, such as saving land, high treatment efficiency, less sludge bulking, strong shock resistance, and ability to withstand high organic loads. However, the high nitrate and nitrogen concentration in the effluent and the difficulty in meeting increasingly stringent standards have limited its engineering application and promotion.

[0004] Anaerobic ammonia oxidation (Anammox) is a novel biological nitrogen removal technology. Its principle involves anaerobic bacteria using ammonia nitrogen as an electron donor and nitrite nitrogen as an electron acceptor to produce nitrogen gas under anaerobic conditions. Its advantage is that it does not require dissolved oxygen or organic carbon sources. Anammox has been successfully applied to treat wastewater with high ammonia nitrogen and low C / N ratios, and its energy efficiency, stable operation, and ease of control are recognized by experts worldwide. However, its application in mainstream urban wastewater treatment plants is still lacking. A stable supply of nitrite nitrogen is a major challenge restricting the engineering application of anammox in urban wastewater treatment.

[0005] In recent years, short-cut denitrification coupled with anaerobic ammonia oxidation (PDA) has attracted widespread attention in the field of urban wastewater treatment. The advantages of this process lie in its ability to simultaneously remove nitrate nitrogen and ammonia nitrogen from wastewater through the action of microorganisms. Furthermore, it features mild reaction conditions, low energy consumption, high treatment efficiency, and low sludge production, effectively addressing the shortcomings and problems of traditional wastewater treatment processes. Currently, positive progress has been made in exploring control strategies for short-cut denitrification coupled with anaerobic ammonia oxidation technology.

[0006] Therefore, to address the issue of high nitrate nitrogen concentration in the effluent from the aerobic granular sludge process for urban wastewater, the side-by-side PDA process can significantly reduce the organic carbon source requirements of the biological nitrogen and phosphorus removal process while ensuring that the nitrogen and phosphorus levels in the effluent from the aerobic granular sludge process meet the standards, thus saving energy and investment for wastewater treatment plants. Summary of the Invention

[0007] The purpose of this invention is to address the shortcomings of existing technologies by providing an SBR combined with a side-mounted PDA urban wastewater treatment device. This addresses the problem that existing traditional nitrification and denitrification treatment processes often suffer from low influent C / N ratios, and the limited organic matter is insufficient to effectively remove nitrogenous pollutants from wastewater. Typically, additional organic carbon sources are needed to meet effluent quality standards, thereby increasing investment and operating costs.

[0008] To achieve the above objectives, the present invention provides an SBR combined with a side-by-side PDA urban wastewater treatment device, comprising:

[0009] A side-by-side PDA device, comprising an anaerobic zone, an anoxic zone, an anaerobic ammonia oxidation zone, and a secondary sedimentation tank, wherein the secondary sedimentation tank is connected to the anaerobic zone via a sludge return pump;

[0010] An aerobic granular sludge SBR device, wherein the output end of the aerobic granular sludge SBR device is connected to the anoxic zone of the adjacent PDA device through an intermediate water tank, and the effluent end of the secondary sedimentation tank is connected to the input end of the aerobic granular sludge SBR device through an effluent return pump.

[0011] The city sewage raw water tank has its output end connected to the input end of the aerobic granular sludge SBR device and the anaerobic zone of the side PDA device.

[0012] Optionally, the effluent from the aerobic granular sludge SBR device and municipal sewage are simultaneously fed into the adjacent PDA device, which together provide a carbon source and reaction matrix for the short-cut denitrification coupled anaerobic ammonium oxidation reaction.

[0013] Optionally, the anaerobic ammonia oxidation zone is provided with a biofilm carrier, with a filling ratio of 30-60%.

[0014] Optionally, the anaerobic ammonia oxidation zone biofilm carrier is provided with a pure anaerobic ammonia oxidation biofilm or a biofilm in which anaerobic ammonia oxidizing bacteria, denitrifying bacteria and denitrifying phosphorus removal bacteria coexist.

[0015] Optionally, the side PDA device is equipped with a pure biofilm or flocculent sludge + biofilm.

[0016] Optionally, the side PDA device is equipped with pure granular sludge or flocculent sludge + granular sludge.

[0017] Optionally, the side-mounted PDA device is a push-flow type.

[0018] Optionally, the aerobic granular sludge SBR device operates in a cycle mode of "influent-stirring-aeration-sedimentation-drainage".

[0019] Optionally, the aerobic granular sludge SBR device is equipped with fully nitrified aerobic granular sludge.

[0020] A method for treating urban wastewater using an SBR-combined side-by-side PDA device, comprising:

[0021] Urban sewage is diverted into a side-by-side PDA device, which then uses a portion of the sludge from the secondary sedimentation tank to return to the anaerobic zone.

[0022] Urban sewage is diverted into or mixed with the secondary sedimentation tank of the adjacent PDA device, and then diverted to the aerobic granular sludge SBR device.

[0023] The effluent from the aerobic granular sludge SBR unit is output to the anoxic zone.

[0024] This invention provides an SBR combined with a side-by-side PDA urban wastewater treatment device, the advantages of which are:

[0025] 1. This device divides urban sewage into two parts, which enter an aerobic granular sludge SBR device and a side-by-side PDA device. The effluent from the former provides a reaction substrate for the latter. The two are cleverly combined and complement each other. The use of short-cut denitrification coupled with anaerobic ammonia oxidation technology to treat high-concentration nitrate nitrogen effluent has positive practical significance. At the same time, the PDA process does not require aeration throughout the process. The ammonia nitrogen in the urban sewage entering the side-by-side PDA device does not need to be converted into nitrite or nitrate nitrogen by aeration and can directly participate in the anaerobic ammonia oxidation reaction, thereby significantly reducing aeration energy consumption and playing an important role in promoting the upgrading of existing sewage treatment plants.

[0026] 2. This system significantly improves the effluent quality of aerobic granular sludge SBRs without requiring any additional chemical additives and with substantial savings in aeration volume. It achieves efficient nitrogen and phosphorus removal from urban wastewater, is stable, has good shock resistance, and exhibits strong robustness. Furthermore, the process layout is flexible, operation is simple, and upgrading new wastewater treatment plants and existing water plants is relatively straightforward, making it easy to promote and apply.

[0027] Other features and advantages of the present invention will be described in detail in the following detailed description section. Attached Figure Description

[0028] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same components in the exemplary embodiments of the invention.

[0029] Figure 1 A schematic diagram of the structure of an SBR combined side-by-side PDA urban wastewater treatment device according to Embodiment 1 of the present invention is shown.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Urban sewage raw water tank; 2. Aerobic granular sludge SBR device; 2.1. Intermediate water tank; 3. Side PDA device; 3.1. Anaerobic zone; 3.2. Anoxic zone; 3.3. Anaerobic ammonia oxidation zone; 3.4. Secondary sedimentation tank. Detailed Implementation

[0032] Preferred embodiments of the invention will now be described in more detail. While preferred embodiments of the invention are described below, it should be understood that the invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the invention will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.

[0033] like Figure 1 As shown, an SBR combined with a side-by-side PDA urban wastewater treatment device includes:

[0034] Side-side PDA device 3 includes an anaerobic zone 3.1, an anoxic zone 3.2, an anaerobic ammonia oxidation zone 3.2, and a secondary sedimentation tank 3.4. The secondary sedimentation tank 3.4 is connected to the anaerobic zone 3.1 via a sludge return pump.

[0035] The output end of the aerobic granular sludge SBR device 2 is connected to the anoxic zone 3.2 of the adjacent PDA device 3 through the intermediate water tank 2.1. The effluent end of the secondary sedimentation tank 3.4 is connected to the input end of the aerobic granular sludge SBR device 2 through the effluent return pump.

[0036] The output end of the urban sewage raw water tank 1 is connected to the input end of the aerobic granular sludge SBR device 2 and the anaerobic zone 3.1 of the adjacent PDA device 3, respectively.

[0037] Specifically, urban sewage is divided into two parts and enters the aerobic granular sludge SBR device 2 and the side-by-side PDA device 3. The effluent from the former provides the reaction substrate for the latter. The two are cleverly combined and complement each other. The use of short-cut denitrification coupled with anaerobic ammonia oxidation technology to treat high-concentration nitrate nitrogen effluent has positive practical significance. At the same time, the PDA process does not require aeration throughout the process. The ammonia nitrogen in the urban sewage entering the side-by-side PDA device 3 does not need to be converted into nitrite or nitrate nitrogen by aeration and can directly participate in the anaerobic ammonia oxidation reaction, thereby significantly reducing aeration energy consumption and playing an important role in promoting the upgrading of existing sewage treatment plants.

[0038] Furthermore, after urban sewage enters the side-by-side PDA device 3, the organic carbon source is mainly used for the denitrification and phosphorus removal process, avoiding the inhibitory effect of organic matter on the anaerobic ammonia oxidation biofilm; at the same time, the side-by-side PDA treatment process realizes short-cut denitrification coupled with anaerobic ammonia oxidation autotrophic denitrification, which greatly reduces the demand for organic carbon source in the denitrification process, thus effectively solving the contradiction of competing carbon sources in the denitrification and phosphorus removal processes in traditional nitrification-denitrification processes.

[0039] In this embodiment, the effluent from the aerobic granular sludge SBR device 2 and the municipal sewage are simultaneously fed into the adjacent PDA device 3, which together provide a carbon source and reaction matrix for the short-cut denitrification coupled anaerobic ammonium oxidation reaction.

[0040] Specifically, by coupling short-cut denitrification with anaerobic ammonia oxidation and denitrification phosphorus removal processes, the problem of high nitrate levels in the effluent from aerobic granular sludge processes can be efficiently solved, facilitating deep nitrogen and phosphorus removal from urban wastewater. The mixed water supply from both processes meets the reaction requirements. The intermediate water tank 2.1 is used to accommodate the cyclical water treatment process of the aerobic granular sludge SBR unit 2, ensuring a stable water supply to the adjacent PDA unit 3, and maintaining a stable ratio between the effluent from the aerobic granular sludge SBR unit 2 and the urban wastewater supply.

[0041] In this embodiment, the anaerobic ammonia oxidation zone 3.2 is provided with a biofilm carrier with a filling ratio of 30-60%.

[0042] Specifically, a biofilm carrier is used to place a biofilm to propagate functional bacterial colonies.

[0043] In this embodiment, the anaerobic ammonia oxidation zone 3.2 biofilm carrier is provided with a pure anaerobic ammonia oxidation biofilm or a biofilm in which anaerobic ammonia oxidizing bacteria, denitrifying bacteria and denitrifying phosphorus removal bacteria coexist.

[0044] Specifically, various functional bacterial groups are propagated through different types of biofilms to meet the needs of water treatment reactions.

[0045] In this embodiment, the side PDA device 3 is equipped with pure biofilm or flocculent sludge + biofilm.

[0046] Specifically, the type and form of sludge should be selected according to the needs;

[0047] Pure biofilm is a biofilm in which anaerobic ammonia oxidizing bacteria, denitrifying bacteria and denitrifying phosphorus removal bacteria coexist;

[0048] The biofilm in flocculent sludge + biofilm can be a pure anaerobic ammonia oxidation biofilm or a biofilm in which anaerobic ammonia oxidation bacteria, denitrifying bacteria and denitrifying phosphorus removal bacteria coexist.

[0049] In this embodiment, the side PDA device 3 is equipped with pure granular sludge or flocculent sludge + granular sludge.

[0050] Specifically, the type and form of sludge should be selected according to the needs;

[0051] Pure granular sludge is a composite granular sludge in which anaerobic ammonia oxidizing bacteria, denitrifying bacteria and denitrifying phosphorus removal bacteria coexist;

[0052] The granular sludge in flocculent sludge + granular sludge can be pure anaerobic ammonia oxidation granular sludge or composite granular sludge in which anaerobic ammonia oxidation bacteria, denitrifying bacteria and denitrifying phosphorus removal bacteria coexist.

[0053] In this embodiment, the side PDA device 3 is a push-flow type.

[0054] Specifically, the plug-flow design ensures a stable and continuous water treatment reaction sequence for the side PDA device 3.

[0055] In this embodiment, the aerobic granular sludge SBR device 2 operates in a cycle mode of "influent-stirring-aeration-sedimentation-drainage".

[0056] In this embodiment, the aerobic granular sludge SBR device 2 is equipped with fully nitrified aerobic granular sludge.

[0057] A method for treating urban wastewater using an SBR-combined side-by-side PDA device, comprising:

[0058] Urban sewage is diverted into the side PDA device 3, and the side PDA device 3 uses the secondary sedimentation tank 3.4 to divert part of the sludge back to the anaerobic zone 3.1;

[0059] Urban sewage is diverted into or mixed with the secondary sedimentation tank 3.4 of the adjacent PDA device 3, and the diverted effluent is sent to the aerobic granular sludge SBR device 2.

[0060] The effluent from the aerobic granular sludge SBR unit 2 is output to the anoxic zone 3.2.

[0061] Example

[0062] The ammonia nitrogen concentration in urban sewage is 25-60 mg / L, the C / N ratio is 1.5-6, and the TP concentration in the influent is 3.6-6.4 mg / L.

[0063] A portion of the urban wastewater enters the aerobic granular sludge SBR unit 2. The SBR unit 2 is inoculated with fully nitrified aerobic granular sludge, with an MLSS of 2300-2600 mg / L. The SBR operates in a cyclical mode: "influent (10 min) - stirring (25 min) - aeration (60 min) - settling (20 min) - effluent (10 min)," with a SRT of 8-12 days. During aeration, the DO concentration is 1.6-2.5 mg / L, and the effluent ratio is 50%. After each cycle, the effluent TP concentration of SBR unit 2 is <0.3 mg / L, the effluent COD concentration is <45 mg / L, the effluent TN concentration is 14-20 mg / L, and the effluent nitrate nitrogen concentration is 13-20 mg / L. The effluent from SBR unit 2 enters the intermediate water tank 2.1, and then enters the anoxic zone 3.2 of the PDA unit.

[0064] Another portion of the urban wastewater enters the anaerobic zone 3.1 of the adjacent PDA unit 3, with the sludge return ratio controlled at 100-200%, thus lowering the C / N ratio in anaerobic zone 3.1 and promoting short-cut denitrification. The sludge-water mixture from anaerobic zone 3.1 and the effluent from the aerobic granular sludge SBR unit 2 mix and enter the anoxic zone 3.2. The mixing flow rate ratio is flexibly adjusted according to the water quality of each component, maintaining the C / N ratio in anoxic zone 3.2 within the range of 1.5-3.0, and reducing NO3. - / NH4 + The pH should be controlled within the range of 1.0-1.2 and between 8.5-9.0 to ensure complete short-cut denitrification, with all nitrate nitrogen converted to nitrite and a nitrite accumulation rate of 100%. Through denitrification and phosphorus removal, the PO4 in the effluent from the anoxic zone (3.2) will be reduced. 3- Concentration less than 0.5 mg / L, COD concentration less than 60 mg / L. Anaerobic ammonia oxidation zone 3.2 NO2 - / NH4 + The PO4 content is controlled within the range of 1.0-1.2. High abundance of the inoculated anaerobic ammonium oxidation biofilm ensures complete anaerobic ammonium oxidation, while denitrification and phosphorus uptake continue in anaerobic ammonium oxidation zone 3.2, resulting in a higher PO4 content in the effluent from zone 3.2. 3- The concentration is less than 0.3 mg / L, and the COD concentration is less than 45 mg / L. The effluent reflux ratio of the side-side PDA device 3 is controlled at 75-100%, and the hydraulic retention time is controlled at 3-9 hours. After the entire system stabilizes, the effluent COD concentration is 36-45 mg / L, and the effluent PO4 concentration is... 3- -P concentration is 0.05~0.30mg / L, effluent NH4 + -N concentration is 0.5-1.5 mg / L, effluent NO3 — NNO3 - -N concentration is 2-3.5 mg / L, TN concentration in effluent is 3.5-8 mg / L, and NH4 in effluent is... +Both -N and TN concentrations meet the requirements of the Class A emission standard.

[0065] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A combined SBR and PDA-based urban wastewater treatment device, characterized in that, include: A side-by-side PDA device, comprising sequentially an anaerobic zone, an anoxic zone, an anaerobic ammonia oxidation zone, and a secondary sedimentation tank, wherein the secondary sedimentation tank is connected to the anaerobic zone via a sludge return pump; An aerobic granular sludge SBR device, wherein the output end of the aerobic granular sludge SBR device is connected to the anoxic zone of the adjacent PDA device through an intermediate water tank, and the effluent end of the secondary sedimentation tank is connected to the input end of the aerobic granular sludge SBR device through an effluent return pump. The city sewage raw water tank, the output end of which is connected to the input end of the aerobic granular sludge SBR device and the anaerobic zone of the side PDA device respectively; Ammonia nitrogen in urban sewage entering the side-by-side PDA device can directly participate in the anaerobic ammonia oxidation reaction without the need for aeration to convert it into nitrite or nitrate nitrogen. The effluent from the aerobic granular sludge SBR device and municipal sewage are simultaneously fed into the adjacent PDA device, which together provide a carbon source and reaction matrix for the short-cut denitrification coupled anaerobic ammonium oxidation reaction.

2. The SBR composite side-by-side PDA urban wastewater treatment device according to claim 1, characterized in that, The anaerobic ammonia oxidation zone is equipped with a biofilm carrier with a filling ratio of 30-60%.

3. The SBR composite side-by-side PDA urban wastewater treatment device according to claim 2, characterized in that, The anaerobic ammonia oxidation zone biofilm carrier is equipped with a pure anaerobic ammonia oxidation biofilm or a biofilm in which anaerobic ammonia oxidizing bacteria, denitrifying bacteria and denitrifying phosphorus removal bacteria coexist.

4. The SBR composite side-by-side PDA urban wastewater treatment device according to claim 1, characterized in that, The side PDA device is equipped with either pure biofilm or flocculent sludge + biofilm.

5. The SBR composite side-by-side PDA urban wastewater treatment device according to claim 1, characterized in that, The side PDA device is equipped with pure granular sludge or flocculent sludge + granular sludge.

6. The SBR composite side-by-side PDA urban wastewater treatment device according to claim 1, characterized in that, The side-mounted PDA device is a push-flow type.

7. The SBR composite side-by-side PDA urban wastewater treatment device according to claim 1, characterized in that, The aerobic granular sludge SBR device operates in a cycle mode of "influent-stirring-aeration-sedimentation-drainage".

8. The SBR composite side-by-side PDA urban wastewater treatment device according to claim 1, characterized in that, The aerobic granular sludge SBR device is equipped with fully nitrified aerobic granular sludge.

9. A method for an SBR-combined side-by-side PDA urban wastewater treatment device, utilizing the SBR-combined side-by-side PDA urban wastewater treatment device according to any one of claims 1-8, characterized in that, include: Urban sewage is diverted into a side-by-side PDA device, which then uses a portion of the sludge from the secondary sedimentation tank to return to the anaerobic zone. Urban sewage is diverted into or mixed with the secondary sedimentation tank of the adjacent PDA device, and then diverted to the aerobic granular sludge SBR device. The effluent from the aerobic granular sludge SBR unit is output to the anoxic zone.

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