A segmented partial nitrification coupled with short-cut denitrification and anaerobic ammonium oxidation treatment system and method

Abstract

This invention discloses a segmented partial nitrification coupled with short-cut denitrification anaerobic ammonia oxidation treatment system and method. The outlet of the influent tank is connected to the inlet at the top of the first biological filter column via an influent pipe and a first extraction pump. The outlet at the bottom of the first biological filter column is connected to the inlet at the top of the second biological filter column via a second extraction pump. The outlet at the bottom of the second biological filter column is connected to the effluent tank via an effluent pipe. The outlet of the aeration pump is connected to the gas inlet on the upper side of both the first and second biological filter columns. This system and method can treat high-nitrogen wastewater with low energy consumption and without the need for external carbon sources. The upper side of the first biological filter column is an aerobic zone; the lower side of the first biological filter column is an anoxic zone; the upper side of the second biological filter column is an aerobic zone; and the lower side of the second biological filter column is an anoxic zone.

Description

Technical Field

[0001] This invention belongs to the field of wastewater biological treatment technology, and relates to a segmented partial nitrification coupled with short-cut denitrification anaerobic ammonia oxidation treatment system and method. Background Technology

[0002] Anaerobic digestion can effectively convert organic matter in high-organic-content wastewater into methane, but the anaerobic digestate is rich in nitrogen and still requires separate treatment to meet discharge standards. Traditional nitrification-denitrification treatment of this type of wastewater has high aeration energy consumption and requires an external carbon source, increasing operating costs, which contradicts the concepts of economic friendliness and pollution reduction and carbon reduction.

[0003] Short-cut nitrification-denitrification (STD) processes control the nitrification process at the nitrite stage without producing nitrate, using nitrite as a substrate for denitrification. This nitrogen removal technology can save 40% of the required carbon source. Furthermore, because the aqueous phase and membrane of the biofilm can provide aerobic and anoxic environments respectively, STD processes can be implemented in biofilm systems.

[0004] Partial nitrification-anaerobic ammonium oxidation (AOB) is a promising and feasible biological nitrogen removal technology that has been widely used. This autotrophic nitrogen removal process consists of two consecutive reactions: aerobic ammonium oxidizing bacteria (AOB) first denitrify NH4+... + -N is partially oxidized aerobically to NO2. - -N, anaerobic ammonia oxidizing bacteria (AnAOB) then process the remaining NH4+. + -N and generated NO2 - -N anaerobic ammonia oxidation to N2. This process produces low sludge, does not require an external carbon source, and saves aeration energy consumption.

[0005] Short-cut nitrification and denitrification still face the problem of insufficient carbon source when treating wastewater with high ammonia nitrogen and low carbon-to-nitrogen ratio. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a segmented partial nitrification coupled with short-cut denitrification anaerobic ammonia oxidation treatment system and method, which can treat high-nitrogen wastewater with low consumption and without the need for external carbon sources.

[0007] To achieve the above objectives, the present invention discloses a segmented partial nitrification coupled short-cut denitrification anaerobic ammonia oxidation treatment system, comprising an inlet tank, an inlet pipe, a first extraction pump, a first biological filter column, a second extraction pump, a second biological filter column, an outlet pipe, an outlet tank, and an aeration pump.

[0008] The outlet of the inlet tank is connected to the inlet at the top of the first biological filter column via an inlet pipe and the first extraction pump. The outlet at the bottom of the first biological filter column is connected to the inlet at the top of the second biological filter column via a second extraction pump. The outlet at the bottom of the second biological filter column is connected to the outlet tank via an outlet pipe. The outlet of the aeration pump is connected to the gas inlet on the upper side of the first biological filter column and the gas inlet on the upper side of the second biological filter column.

[0009] The upper part of the first biofilter column is the aerobic zone; the lower part of the first biofilter column is the anoxic zone; the upper part of the second biofilter column is the aerobic zone, and the lower part of the second biofilter column is the anoxic zone.

[0010] Both the first and second sections of the biofilter are filled with suspended biological packing material K1.

[0011] Concentrated activated sludge is added to the middle section of the first biofilter column.

[0012] Anaerobic ammonia oxidation sludge is added to the bottom of the second stage of the biological filter column.

[0013] The second stage of the biofilter column is initiated by introducing NH4. + -N and NO2 - Matrix solutions with -N concentrations of 50 mg / L and 53 mg / L, respectively.

[0014] It also includes a DO detector and an online monitoring device, wherein the DO detector is connected to the upper side of the first biological filter column and the upper side of the second biological filter column, and the online monitoring device is connected to the DO detector and the aeration pump.

[0015] The first section of the biofilter column is provided with a first exhaust port at the top; the second section of the biofilter column is provided with a second exhaust port at the top.

[0016] Both the first and second biological filter columns have water inlets on their upper sides.

[0017] The segmented partial nitrification coupled with short-cut denitrification anaerobic ammonia oxidation treatment method of the present invention includes the following steps:

[0018] Wastewater enters the aerobic section of the first-stage biological filter column through the inlet at the top. Simultaneously, an aeration pump aerates the aerobic section, where partial nitrification occurs, removing some of the NH4+ from the wastewater. + -N is converted to NO2 - -N, and then enters the anoxic zone at the bottom of the first biological filter column, utilizing the SCOD in the wastewater and the NO2 produced in the aerobic zone. - -N undergoes denitrification;

[0019] The wastewater from the first stage of the biological filter enters the aerobic zone on the upper side of the second stage of the biological filter for partial nitrification, reducing the NH4+ in the effluent from the first stage of the biological filter. + -N partially nitrites to NO2. - -N, and then enters the anoxic zone at the bottom of the second biofilter column, where anaerobic ammonium oxidation removes NH4+. + -N and NO2 - -N, the treated wastewater from the second stage of the biological filter column enters the effluent tank.

[0020] In the aerobic section above the second biological filter column, the NH4+ from the effluent of the first biological filter column is... + -N is converted to NO2 - -N, the conversion ratio is controlled at NH4 + -N:NO2 - -N=1:(1.1~1.32).

[0021] The present invention has the following beneficial effects:

[0022] The segmented partial nitrification coupled with short-cut denitrification anaerobic ammonium oxidation treatment system and method described in this invention employs a biofilter column with mid-to-upper stage aeration. Utilizing its high height-to-diameter ratio, it combines aerobic and anaerobic denitrification in separate zones. This allows partial nitrification, denitrification, and partial nitrification-anaerobic ammonium oxidation to occur in different sections of the same reactor, achieving efficient and low-consumption denitrification through a combined process while reducing land area and aeration volume, thus saving operating costs. Furthermore, it should be noted that the segmented removal of nitrogen from wastewater after segmented nitrification in this invention gradually reduces the high ammonia nitrogen concentration in the wastewater, minimizing the inhibitory effect of high ammonia nitrogen on subsequent anaerobic ammonium oxidation. Moreover, the second aeration zone can better control the ratio of ammonia nitrogen to nitrite nitrogen at 1:1.1 to 1:1.32, providing a suitable substrate ratio for anaerobic ammonium oxidation. It should also be noted that the first stage of the biological filter column can stably and efficiently remove organic matter from wastewater with high ammonia nitrogen and low C / N ratio. Under conditions without external carbon sources, it can remove some nitrogen by using SCOD in the wastewater through low aeration combined with short-cut denitrification, and can avoid the impact of high organic load on the anaerobic ammonia oxidation stage. Attached Figure Description

[0023] Figure 1 This is a structural diagram of the present invention.

[0024] Among them, 1 is the inlet pool, 1-1 is the inlet pipe, 2 is the first biological filter column, 1-2 is the first extraction pump, 2-1 is the first exhaust port, 2-2 is the water intake port, 2-3 is the aeration pump, 2-4 is the second exhaust port, 2-5 is the DO detector, 2-6 is the constant temperature system, 2-7 is the online monitoring device, 2-8 is the second extraction pump, 3 is the second biological filter column, 4 is the outlet pool, and 4-1 is the outlet pipe. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, 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 merely some embodiments of the present invention, not all embodiments, and are not intended to limit the scope of the present invention. Furthermore, in the following description, descriptions of well-known structures and technologies are omitted to avoid unnecessary confusion regarding the concepts disclosed in the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort should fall within the scope of protection of the present invention.

[0026] The accompanying drawings show structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not drawn to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0027] refer to Figure 1 The segmented partial nitrification coupled short-cut denitrification anaerobic ammonia oxidation treatment system of the present invention includes an inlet tank 1, a first-stage biological filter column 2, a second-stage biological filter column 3, and an outlet tank 4.

[0028] The outlet of the inlet pool 1 is connected to the inlet at the top of the first biological filter column 2 via the inlet pipe 1-1 and the first extraction pump 1-2. The outlet at the bottom of the first biological filter column 2 is connected to the inlet at the top of the second biological filter column 3 via the second extraction pump 2-8. The outlet at the bottom of the second biological filter column 3 is connected to the outlet pool 4 via the outlet pipe 4-1.

[0029] In this embodiment, an aeration pump 2-3 is also included. The outlet of the aeration pump 2-3 is connected to the gas inlet on the side of the first biological filter column 2 and the gas inlet on the side of the second biological filter column 3.

[0030] In this embodiment, a DO detector 2-5 is also included, wherein the DO detector 2-5 is connected to the upper side of the first biofilter column 2 and the upper side of the second biofilter column 3.

[0031] In this embodiment, an online monitoring device 2-7 is also included, which is connected to the DO detector 2-5 and the aeration pump 2-3.

[0032] In this embodiment, a constant temperature system 2-6 is also included for controlling the temperature of the first biological filter column 2 and the second biological filter column 3.

[0033] In this embodiment, the top of the first section of the biofilter column 2 is provided with a first exhaust port 2-1; the top of the second section of the biofilter column 3 is provided with a second exhaust port 2-4.

[0034] In this embodiment, water inlets 2-2 are provided on the upper side of both the first biological filter column 2 and the second biological filter column 3.

[0035] In this embodiment, the first biological filter column 2 and the second biological filter column 3 are filled with suspended biological packing material K1 with a filling rate of 100%. The biological filter column with mid-to-upper section aeration is used to carry out denitrification by combining aerobic and anaerobic zones, taking advantage of its large height-to-diameter ratio. This allows some nitrification, denitrification and anaerobic ammonia oxidation to take place in different sections of the same reactor.

[0036] refer to Figure 1 The segmented partial nitrification coupled with short-cut denitrification anaerobic ammonia oxidation treatment method of the present invention includes the following steps:

[0037] 1) Start-up of the partial nitrification short-cut denitrification stage:

[0038] Concentrated activated sludge is added to the middle section of the first-stage biological filter column 2. Wastewater enters from the inlet at the top of the first-stage biological filter column 2. The initial hydraulic retention time is set to 16 hours, and the temperature is controlled at 25–31°C. Aeration is carried out in the middle and upper sections, with the upper section being an aerobic zone for partial nitrification. The DO concentration in the aerobic zone is controlled at 0.5–0.8 mg / L through aeration. Approximately half of the NH4+ in the influent is removed. + -N is converted to NO2 - -N, the next section is the anoxic zone, utilizing SCOD in the wastewater and NO2 produced in the aerobic zone. - -N undergoes denitrification.

[0039] Increase the influent nitrogen load, initially set the hydraulic retention time to 16 hours, and gradually shorten the hydraulic retention time to 4 hours. NH4 + When the removal rate of -N stabilizes at around 50%, the partial nitrification short-cut denitrification stage is successfully started.

[0040] 2) Start-up of part of the nitrification anaerobic ammonium oxidation section:

[0041] Anaerobic ammonia oxidation sludge is added to the bottom of the second stage biological filter column 3, and NH4 is introduced. + -N and NO2 -Substrate solutions with -N concentrations of 50 mg / L and 53 mg / L were allowed to stand for 24 hours at 25°C to allow biofilm formation. After biofilm formation, concentrated activated sludge was added from the top. The effluent from the first stage biological filter column 2 was used as influent and added to the second stage biological filter column 3 through the top inlet. Aeration was carried out on the upper side of the second stage biological filter column 3, controlling it as an aerobic zone for partial nitrification. The NH4+ effluent from the first stage biological filter column 2... + -N is converted to NO2 - -N, the conversion ratio is controlled at NH4 + -N:NO2 - -N = 1:1.1~1.32, the lower section is an anoxic zone where anaerobic ammonia oxidation reaction takes place.

[0042] Increase the influent nitrogen load, initially set the hydraulic retention time to 16 hours, and gradually shorten the hydraulic retention time to 4 hours. The NH4+ effluent from the reactor... + When the removal rate of -N reaches 85%, the partial nitrification anaerobic ammonium oxidation stage is successfully started.

[0043] 3) Partial nitrification short-cut denitrification section and partial nitrification anaerobic ammonium oxidation section are operated in series:

[0044] Gradually shorten the hydraulic retention time, increase the influent nitrogen load, and increase the effluent NH4. + When the nitrogen removal rate reaches 92%, the segmented partial nitrification coupled with short-cut denitrification anaerobic ammonium oxidation system is successfully started.

[0045] This invention removes nitrogen from wastewater in stages after nitrification, which can gradually reduce the concentration of high ammonia nitrogen in the wastewater and reduce the inhibitory effect of high ammonia nitrogen on subsequent anaerobic ammonia oxidation. In addition, the second aeration zone can better control the ratio of ammonia nitrogen to nitrite nitrogen at 1:1.1 to 1:1.32, providing a suitable substrate ratio for anaerobic ammonia oxidation.

[0046] The first biological filter column 2 in this invention can stably and efficiently remove organic matter from wastewater with high ammonia nitrogen and low C / N ratio. Under conditions without external carbon source, it can remove part of the nitrogen by using SCOD in the wastewater through low aeration combined with short-cut denitrification, and can avoid the impact of high organic load on the anaerobic ammonia oxidation section.

[0047] Example 1

[0048] In this embodiment, two biological filter columns with an effective volume of 2L are connected in series. Aeration pumps 2-3 are installed in the middle and upper sections. 300ml of concentrated activated sludge is added to the middle of the first biological filter column 2, with an MLVSS of 14.20g / L. 350ml of anaerobic ammonia oxidation activated sludge is added to the bottom of the second biological filter column 3, with an MLVSS of 11.5g / L. The temperature is controlled at 28℃.

[0049] Wastewater quality index NH4 + -N concentration is 500–1000 mg / L, SCOD concentration is 1000–3000 mg / L, and pH is 7.5–8.4.

[0050] Start-up of partial nitrification short-cut denitrification stage:

[0051] In the first stage of the biological filter column 2, the DO concentration in the aerobic section is controlled at 0.5–0.8 mg / L through aeration, while half of the NH4+ in the influent is removed. + -N is converted to NO2-N; the next section is the anoxic zone, utilizing the SCOD in the wastewater and the NO2 produced in the aerobic zone. - -N undergoes denitrification.

[0052] Under a hydraulic retention time of 4 hours, after 65 days of continuous operation, the effluent NH4 content was... + -N removal rate remained at 51.44%, and average effluent NH4 content was [missing information]. + The -N concentration was 334.36 mg / L, and the partial nitrification short-cut denitrification stage was successfully started.

[0053] Start-up of part of the nitrification anaerobic ammonium oxidation section:

[0054] Anaerobic ammonia oxidation sludge is added to the bottom of the second stage biological filter column 3, and NH4 is introduced. + -N and NO2 - Substrate solutions with -N concentrations of 50 mg / L and 53 mg / L were allowed to stand for 24 hours at 25°C to allow biofilm formation. The DO concentration was controlled at 0.5–0.8 mg / L through aeration. The effluent NH4+ from the first stage of the biological filter column 2... + Half of the -N is converted into NO2. - -N, average effluent NH4 + -N:NO2 - -N = 1:1.24.

[0055] Under a hydraulic retention time of 4 hours, after 65 days of continuous operation, NH4 + -N removal rate remained at 97.44%, and average effluent NH4 content was [missing information]. + The -N concentration was 8.56 mg / L, and the partial nitrification short-cut denitrification stage was successfully started.

[0056] The first biological filter column 2 and the second biological filter column 3 operate in series:

[0057] Partial nitrification short-cut denitrification section and partial nitrification anaerobic ammonium oxidation section are operated in series, further shortening the hydraulic retention time to 3 hours, and operating stably for 30 days, with an average NH4 content in the effluent. +-N removal rate was 98.54%.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A process for a partial nitritation coupled shortcut denitrification anaerobic ammonia oxidation treatment in stages, characterized in that, The application discloses a treatment system based on a segmented partial nitritation coupled with short-cut denitrification and anaerobic ammonia oxidation, and has the characteristics that the treatment system comprises a water inlet tank (1), a water inlet pipe (1-1), a first extraction pump (1-2), a first-stage biological filter column (2), a second extraction pump (2-8), a second-stage biological filter column (3), a water outlet pipe (4-1), a water outlet tank (4) and an aeration pump (2-3). The outlet of the water inlet tank (1) is connected with the inlet at the top of the first-stage biological filter column (2) through the water inlet pipe (1-1) and the first extraction pump (1-2), the outlet at the bottom of the first-stage biological filter column (2) is connected with the inlet at the top of the second-stage biological filter column (3) through the second extraction pump (2-8), and the outlet at the bottom of the second-stage biological filter column (3) is connected with the water outlet tank (4) through the water outlet pipe (4-1). The upper side of the first-stage biological filter column (2) is an aerobic section, the lower side of the first-stage biological filter column (2) is an anoxic section, the upper side of the second-stage biological filter column (3) is an aerobic section, and the lower side of the second-stage biological filter column (3) is an anoxic section. Anaerobic ammonia oxidation sludge is added to the bottom of the second-stage biological filter column (3). The second section of the biofilter column (3) is supplied with NH4 + -N and NO2 - The substrate solution has a concentration of 50 mg / L and 53 mg / L of -N, respectively; The treatment system comprises the following steps: The wastewater enters into the aerobic section of the first biological filter column (2) from the inlet at the top of the first biological filter column (2), and the aerobic section is aerated by the aeration pump (2-3), and a partial nitritation reaction is carried out in the aerobic section to convert part of NH4 + -N in the wastewater into NO2 - -N, and then enters into the anoxic section at the lower side of the first biological filter column (2) to perform denitrification by using SCOD in the wastewater and NO2 - -N generated in the aerobic section. The effluent from the first-stage biofilter column (2) enters the aerobic section at the upper side of the second-stage biofilter column (3) to perform a partial nitrosation reaction, converting NH4 + -N in the effluent from the first-stage biofilter column (2) into NO2 - -N, and then enters the anoxic section at the lower side of the second-stage biofilter column (3), where anammox reaction removes NH4 + -N and NO2 - -N, and the treated effluent from the second-stage biofilter column (3) enters the effluent tank (4). In the aerobic section on the upper side of the second biofilter column (3), the effluent NH4 + -N is converted to NO2 - -N, and the conversion ratio is controlled to be NH4 + -N:NO2 - -N=1: (1.1~1.32).

2. The process according to claim 1, wherein the process is a process for a partial de- nitrification coupled short-cut denitrification ANAMMOX process, characterized in that, The first-stage biological filter column (2) and the second-stage biological filter column (3) are both filled with suspended biological fillers K1.

3. The process according to claim 1, wherein the process is a process for a partial de- nitrification coupled ANAMMOX process, characterized in that, The middle part of the first-stage biological filter column (2) is added with concentrated activated sludge.

4. The process according to claim 1, wherein the process is a process for a partial de- nitrification coupled ANAMMOX process, characterized in that, The treatment system further comprises a DO detector (2-5) and an online monitoring device (2-7), wherein the DO detector (2-5) is connected with the upper side of the first-stage biological filter column (2) and the upper side of the second-stage biological filter column (3), and the online monitoring device (2-7) is connected with the DO detector (2-5) and the aeration pump (2-3).

5. The process according to claim 1, wherein the process is a process for a partial de- nitrification coupled ANAMMOX process, characterized in that, The top of the first-stage biological filter column (2) is provided with a first exhaust port (2-1), and the top of the second-stage biological filter column (3) is provided with a second exhaust port (2-4).

6. The process according to claim 1, wherein The upper side of the first-stage biological filter column (2) and the upper side of the second-stage biological filter column (3) are both provided with a water taking port (2-2).

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