Pna-ifas process and apparatus thereof

Abstract

The present application relates to a kind of PNA-IFAS process and its device.The PNA-IFAS process includes: the sludge-water mixture obtained by mixing sewage with flocculation sludge with PNA activity, under the condition of aeration oxygenation, sludge-water mixture sequentially passes through fiber filler, polyethylene filler and polyurethane filler to complete denitrification, then through sludge-water separation to obtain sewage meeting discharge standard;Wherein, in the effective volume of reactor, the volume percentage of fiber filler is 1%-5%, the volume percentage of polyethylene filler is 10%-25%, and the volume percentage of polyurethane filler is 1%-5%.The PNA-IFAS process described in the present application adds flocculation sludge with PNA activity, and cooperates to control the proportion and order of mixed filler, so that the biomass in the reactor system is not easy to lose, the start-up time is fast, and the PNA-IFAS system is continuously and efficiently denitrified.

Description

Technical Field

[0001] This invention relates to the field of wastewater biological treatment technology, and in particular to the PNA-IFAS process and its apparatus. Background Technology

[0002] The presence of nitrogen pollutants in wastewater, especially high concentrations of ammonia nitrogen, poses a serious threat to aquatic environments and human health. Traditional biological nitrogen removal processes typically rely on complete nitrification-denitrification, which requires not only high aeration levels but also large amounts of carbon source input, resulting in high energy and material consumption. Therefore, developing efficient and low-consumption nitrogen removal technologies has become a research hotspot in the field of wastewater treatment.

[0003] Short-cut nitrification-anaerobic ammonia oxidation (PNA) technology removes nitrogen by partially oxidizing ammonia nitrogen to nitrite, followed by the direct conversion of ammonia nitrogen and nitrite into nitrogen gas using anaerobic ammonia-oxidizing bacteria (Anammox). Compared to traditional nitrification-denitrification processes, PNA technology offers significant advantages such as reduced aeration energy consumption, no need for external carbon sources, and lower sludge production, making it particularly suitable for treating high-ammonia nitrogen wastewater.

[0004] The International Flocculent Biofilm System (IFAS) combines the advantages of flocculent sludge and biofilm. By simultaneously containing suspended flocculent sludge and attached biofilm in the reactor, it significantly increases biomass and biodiversity. This design not only improves the system's treatment efficiency but also enhances its tolerance to water quality fluctuations. Combining the IFA process with the PNA process can further optimize nitrogen removal, especially under complex conditions such as low temperature and low C / N ratio.

[0005] The PNA-IFAS process is widely used in practical engineering. However, during the start-up phase, the process has a long initial start-up time and is prone to problems such as sludge loss and biofilm detachment. As the operating time increases, the biofilm thickness increases, causing increased mass transfer resistance and decreased nitrogen removal efficiency, posing a challenge to continuous and efficient nitrogen removal. Summary of the Invention

[0006] Therefore, it is necessary to provide a PNA-IFAS process and apparatus to address the above-mentioned problems. The PNA-IFAS process of the present invention adds flocculent sludge with PNA activity and controls the proportion and sequence of mixed packing materials in a coordinated manner, so that the biomass of the PNA-IFAS system is not easily lost, the reaction start-up time is fast, and continuous and efficient denitrification is achieved.

[0007] A PNA-IFAS process includes the following steps:

[0008] The sludge-water mixture obtained by mixing wastewater with flocculent sludge with PNA activity is denitrified by sequentially passing through fiber packing, polyethylene packing and polyurethane packing under aeration and oxygenation conditions, and then the sludge-water mixture is separated to obtain wastewater that meets the discharge standards.

[0009] In the effective volume of the reactor, the volume percentage of the fiber packing is 1%-5%, the volume percentage of the polyethylene packing is 10%-25%, and the volume percentage of the polyurethane packing is 1%-5%.

[0010] In one embodiment, the volume percentage of the polyurethane filler is greater than the volume percentage of the fiber filler.

[0011] In one embodiment, the mass concentration of flocculent sludge in the mud-water mixture is 5000 mg / L-8000 mg / L.

[0012] In one embodiment, the mass concentration of flocculent sludge in the denitrification system is 1000 mg / L-1500 mg / L.

[0013] In one embodiment, when the mass concentration of flocculent sludge in the denitrification system increases from 1000 mg / L-1500 mg / L to over 2000 mg / L, some of the packing material is replaced with the same type of blank packing material.

[0014] In one embodiment, the volume of the replaced blank packing is 0.05%-2% of the total volume of the same type of packing.

[0015] In one embodiment, after sludge-water separation, a portion of the wastewater is recycled for denitrification.

[0016] In one embodiment, the wastewater flow rate for denitrification is 100%-300% of the influent flow rate.

[0017] An apparatus for the PNA-IFAS process as described above includes an inlet, an integrated continuous flow PNA reactor, and an outlet, wherein the integrated continuous flow PNA reactor includes a microporous aeration system, a fiber packing frame, a polyethylene packing frame, and a polyurethane packing frame arranged sequentially in the direction of water flow, and a built-in separator disposed at the outlet.

[0018] In one embodiment, the integrated continuous flow PNA reactor further includes a submersible agitator;

[0019] And / or, the device further includes a water return system disposed between the inlet and the outlet;

[0020] And / or, the device further includes a lifting device and a mounting slot, wherein the fiber packing frame, the polyethylene packing frame and the polyurethane packing frame are all fixed in the mounting slot, and the lifting device is used to control the movement of any packing frame.

[0021] In the PNA-IFAS process described in this invention, flocculent sludge with PNA activity is inoculated, and a biofilm is formed using mixed blank packing as a carrier. Wastewater sequentially passes through fiber packing, polyethylene packing, and polyurethane packing in specific volume ratios, achieving better biofilm formation. This ensures that the overall biofilm thickness is similar and that each packing adapts to the corresponding concentration gradient treatment efficiency, greatly shortening the start-up time of the PNA-IFAS system. Furthermore, the flocculent sludge and the aerobic and anaerobic ammonia oxidizing bacteria in the biofilm efficiently and synergistically complete the short-cut nitrification and anaerobic ammonia oxidation reaction to remove nitrogen from the wastewater, achieving continuous and efficient nitrogen removal in the PNA-IFAS system.

[0022] Therefore, the PNA-IFAS process described in this invention has the advantages of fast reaction start-up time, low biomass loss in the system, high denitrification efficiency, low aeration energy consumption, and no need for external carbon source, which is of great significance for improving the feasibility and economy of PNA-IFAS process engineering application. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a schematic diagram of the PNA-IFAS device.

[0025] The components include: 1. Inlet; 2. Integrated continuous flow PNA reactor; 3. Microporous aeration system; 4. Submersible agitator; 5. Fiber packing frame; 6. Polyethylene packing frame; 7. Polyurethane packing frame; 8. Built-in separator; 9. Outlet reflux system; 10. Outlet; 11. Lifting device; 12. Mounting slot. Detailed Implementation

[0026] To facilitate understanding of the present invention, it will be described in more detail below. However, it should be understood that the present invention can be implemented in many different forms and is not limited to the embodiments or examples described herein. Rather, these embodiments or examples are provided to make the disclosure of the present invention more thorough and complete.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments or examples only and is not intended to limit the invention. The optional scope of the term "and / or" as used herein includes any one of two or more of the related listed items, as well as any and all combinations of the related listed items, including any two related listed items, any more related listed items, or a combination of all related listed items.

[0028] This invention provides a PNA-IFAS process, comprising the following steps:

[0029] The sludge-water mixture obtained by mixing wastewater with flocculent sludge with PNA activity is then subjected to denitrification by sequentially passing through fiber packing, polyethylene packing, and polyurethane packing under aeration and oxygenation conditions. Finally, the mixture is separated into sludge and water to obtain wastewater that meets the discharge standards.

[0030] In the effective volume of the reactor, the volume percentage of the fiber packing is 1%-5%, the volume percentage of the polyethylene packing is 10%-25%, and the volume percentage of the polyurethane packing is 1%-5%.

[0031] In the PNA-IFAS process described in this invention, flocculent sludge with PNA activity is inoculated, and a biofilm is formed using mixed blank packing as a carrier. Wastewater sequentially passes through fiber packing, polyethylene packing, and polyurethane packing in specific volume ratios, achieving better biofilm formation. This ensures that the overall biofilm thickness is similar and that each packing adapts to the corresponding concentration gradient treatment efficiency, greatly shortening the start-up time of the PNA-IFAS system. Furthermore, the flocculent sludge and the aerobic and anaerobic ammonia oxidizing bacteria in the biofilm efficiently and synergistically complete the short-cut nitrification and anaerobic ammonia oxidation reaction to remove nitrogen from the wastewater, achieving continuous and efficient nitrogen removal in the PNA-IFAS system.

[0032] Specifically, fiber packing material, based on its unique high aspect ratio fibrous structure, has a high biofilm formation rate, which is beneficial for removing organic matter and suspended solids from wastewater. This provides better reaction conditions for the subsequent polyethylene packing biofilm and reduces the reaction start-up time. Soft fiber packing material is preferred among these materials.

[0033] Although polyethylene packing has a lower biofilm attachment rate compared to fiber packing, the biofilm adheres stably to it and is not easily detached. The biofilm provides an anaerobic microenvironment for anaerobic ammonia oxidizing bacteria, which convert ammonia nitrogen and nitrite nitrogen into nitrogen gas under anaerobic conditions, thereby achieving a better denitrification effect, improving denitrification efficiency, and reducing reaction start-up time.

[0034] Polyurethane packing has a unique porous structure, which is conducive to the containment of microorganisms that detach from fiber packing and polyethylene packing, ensuring that the biomass in the system is not easily lost, thereby making the denitrification efficiency continuously stable.

[0035] It is understood that, within the effective volume of the reactor, the volume percentage of the fiber filler includes, but is not limited to, any one of 1%, 2%, 3%, 4%, 5%, or any range between two; the volume percentage of the polyethylene filler includes, but is not limited to, any one of 10%, 12%, 15%, 18%, 20%, 23%, 25%, or any range between two; and the volume percentage of the polyurethane filler includes, but is not limited to, any one of 1%, 2%, 3%, 4%, 5%, or any range between two.

[0036] Preferably, the volume percentage of the polyurethane filler is greater than that of the fiber filler, which is beneficial for further improving the continuous stability of the denitrification efficiency.

[0037] It should be noted that the mass concentration of flocculent sludge in the reactor is highest at the initial stage of the reaction. As the reaction proceeds, the flocculent sludge gradually transfers to the packing material, causing biofilm formation on the packing. In a stable denitrification system, the mass concentration of flocculent sludge decreases by about 80%-90% compared to the initial concentration. As the biofilm in the packing continues to increase, when the biofilm load in the packing becomes supersaturated, the flocculent sludge on the packing gradually returns to the water, causing the mass concentration of flocculent sludge to increase compared to the mass concentration of flocculent sludge in a stable denitrification system.

[0038] Preferably, the mass concentration of flocculent sludge in the mud-water mixture is 5000 mg / L-8000 mg / L, including but not limited to any one of 5000 mg / L, 6000 mg / L, 7000 mg / L, 8000 mg / L, or any range between two of them.

[0039] Further preferred, the mass concentration of flocculent sludge in the denitrification system is 1000mg / L-1500mg / L, including but not limited to any one of 1000mg / L, 1100mg / L, 1200mg / L, 1300mg / L, 1400mg / L, 1500mg / L, or any range between two of them.

[0040] In one embodiment, when the mass concentration of flocculent sludge in the denitrification system increases from 1000 mg / L-1500 mg / L to over 2000 mg / L, some of the packing material is replaced with the same type of blank packing material to maintain the sustainable and efficient operation of the PNA-IFAS system and further ensure that the PNA-IFAS process can achieve long-term and efficient denitrification.

[0041] Preferably, the volume of the replacement blank packing is 0.05%-2% of the total volume of the same packing, including but not limited to any one of 0.05%, 0.1%, 0.5%, 0.8%, 1%, 1.5%, 2% or any range between two of them.

[0042] By separating sludge from water, sludge can be retained in the reactor, working together with polyurethane packing to ensure that biomass in the system is not easily lost, maintaining the sludge concentration in the reactor, thereby ensuring a continuous and stable denitrification efficiency.

[0043] In one embodiment, after the mud and water are separated, a portion of the wastewater is recycled for denitrification.

[0044] Preferably, the wastewater flow rate for denitrification is 100%-300% of the influent flow rate, including but not limited to any one of 100%, 150%, 200%, 250%, 300%, or any range between two.

[0045] Therefore, the PNA-IFAS process described in this invention has advantages such as fast start-up time, low biomass loss within the system, high denitrification efficiency, low aeration energy consumption, and no need for external carbon sources. Theoretically, it can reduce aeration energy consumption by 60% and carbon source by 100%, with less sludge discharge and less greenhouse gas N2O generation. It is of great significance for improving the feasibility and economy of PNA-IFAS process engineering applications.

[0046] Combination Figure 1 As shown, the apparatus used in the PNA-IFAS process described above provided by the present invention includes an inlet 1, an integrated continuous flow PNA reactor 2, and an outlet 10. The integrated continuous flow PNA reactor 2 includes a microporous aeration system 3, a fiber packing frame 5, a polyethylene packing frame 6, and a polyurethane packing frame arranged sequentially in the direction of water flow, and a built-in separator 8 disposed at the outlet.

[0047] It should be noted that the device described in this invention does not limit the mixing method of wastewater and flocculent sludge with PNA activity. Wastewater and flocculent sludge with PNA activity can be mixed first to form a mud-water mixture, and then the mud-water mixture can be introduced from the inlet 1. Alternatively, flocculent sludge can be pre-set in the integrated continuous flow PNA reactor 2, and then wastewater can be introduced from the inlet 1 so that the wastewater and flocculent sludge are mixed in the integrated continuous flow PNA reactor 2.

[0048] Preferably, the inlet 1 is located near the bottom of the integrated continuous flow PNA reactor 2, below the liquid surface.

[0049] Preferably, from the bottom to the top of the integrated continuous flow PNA reactor 2, an inlet 1, a microporous aeration system 3, and a packing frame are arranged in sequence.

[0050] Preferably, the microporous aeration system 3 is distributed at the bottom of the fiber packing frame 5, the polyethylene packing frame 6, and the polyurethane packing frame 7, which is conducive to uniform oxygen supply and ensures the continuous and stable denitrification process.

[0051] Preferably, in the effective volume of the integrated continuous flow PNA reactor 2, the fiber packing frame 5 has a volume percentage of 1%-5%, the polyethylene packing frame 6 has a volume percentage of 10%-25%, and the polyurethane packing frame 7 has a volume percentage of 1%-5%.

[0052] It should be noted that the fiber packing frame 5, the polyethylene packing frame 6, and the polyurethane packing frame 7 can be independent compartments or a single integrated compartment; this invention does not impose any limitation on this. When the packing frames are independent compartments, the compartments of different packing frames can be connected through holes or pipes to ensure water flow.

[0053] By designing a built-in separator 8 at the outlet, mud and water can be separated, and sludge can be retained in the reactor. Together with the polyurethane packing, it ensures that the biomass in the system is not easily lost, maintains the sludge concentration in the reactor, and thus makes the denitrification efficiency continuously stable.

[0054] In one embodiment, the integrated continuous flow PNA reactor further includes a submersible agitator 4, which can mix the wastewater and flocculent sludge evenly and drive the water flow.

[0055] In one embodiment, the device further includes an effluent recirculation system 9 disposed between the inlet 1 and the outlet 10, which allows a portion of the wastewater after mud-water separation to be recycled for denitrification.

[0056] In one embodiment, the device further includes a lifting device 11 and a mounting slot 12, wherein the fiber packing frame 5, the polyethylene packing frame 6, and the polyurethane packing frame 7 are all fixed in the mounting slot 12. The lifting device 11 is used to control the movement of any packing frame, facilitating the replacement of blank packing during system operation. It is understood that the lifting device 11 is located on the outside of the device for easy operation.

[0057] The apparatus used in the PNA-IFAS process described in this invention has a high nitrogen removal load, a small footprint, and high feasibility for engineering application.

[0058] The PNA-IFAS process and apparatus will be further described below through specific embodiments. However, those skilled in the art will understand that the following embodiments are for illustrative purposes only and should not be considered as limiting the scope of the invention. Unless otherwise specified, specific conditions in the embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0059] Example 1

[0060] The wastewater being treated is synthetic wastewater with the following specific characteristics: COD 100 mg / L - 200 mg / L, NH4+ + -N is 100mg / L-200mg / L, NO3 - -N≤5mg / L, NO2 - -N≤5mg / L.

[0061] Synthetic wastewater is fed into an integrated continuous flow PNA reactor via the inlet. Oxygen is supplied by a microporous aeration system. During the initial startup phase, the initial flocculent sludge concentration in the reactor is 6000 mg / L. The sludge-water mixture sequentially passes through a fiber packing frame (1% of the reactor's effective volume), a polyethylene packing frame (20% of the reactor's effective volume), and a polyurethane packing frame (5% of the reactor's effective volume) to complete denitrification. Then, it undergoes sludge-water separation via an internal separator. A portion of the separated wastewater is returned to the inlet via an effluent recirculation system, while the remainder is discharged. The recirculated wastewater flow rate is 200% of the influent flow rate.

[0062] The experimental results show that after the process is stabilized, the COD removal rate reaches over 90%, the nitrogen removal rate reaches about 85%, and the effluent NH4 content is low. + -N is less than 5 mg / L, and total nitrogen is less than 15 mg / L.

[0063] Example 2

[0064] The treatment target is landfill leachate, with the following specific water quality: COD 2000mg / L-3000mg / L, NH4+ + -N is 1800mg / L-2000mg / L, NO3 - -N≤2mg / L, NO2 - -N≤0.5mg / L.

[0065] Landfill leachate is fed into an integrated continuous flow PNA reactor via the inlet, where oxygen is supplied by a microporous aeration system. During initial startup, the initial flocculent sludge concentration in the reactor is 8000 mg / L. The sludge-water mixture sequentially passes through a fiber packing frame (3% of the reactor's effective volume), a polyethylene packing frame (20% of the reactor's effective volume), and a polyurethane packing frame (5% of the reactor's effective volume) for denitrification. Then, it undergoes sludge-water separation via an internal separator. A portion of the separated wastewater is returned to the inlet via an effluent recirculation system, while the remainder is discharged. The recirculated wastewater flow rate is 100% of the influent flow rate.

[0066] When the process is running stably, the mass concentration of flocculent sludge in the reactor is 1200 mg / L. Experimental results show that after the process stabilizes, the nitrogen removal rate reaches over 90%, and the effluent NH4... + -N is below 30 mg / L, and total nitrogen is below 50 mg / L.

[0067] After running the process for 200 days, the mass concentration of flocculent sludge in the reactor was 2200 mg / L, and the removal rate decreased to about 85%. One percent of the polyethylene packing was then removed and replaced with blank polyethylene packing. After 30 days of operation, the experimental results showed that after replacing the packing, the nitrogen removal rate reached about 90%, and the effluent NH4... + -N is below 30 mg / L, and total nitrogen is below 50 mg / L. Therefore, continuous and efficient nitrogen removal can be achieved by replacing the packing material.

[0068] Example 3

[0069] The treatment target is kitchen wastewater, with the following specific water quality: COD 2000mg / L-3000mg / L, NH4+ + -N is 3000mg / L-4000mg / L, NO3 - -N≤10mg / L, NO2 - -N≤5mg / L.

[0070] Kitchen wastewater is fed into an integrated continuous flow PNA reactor through the inlet. Oxygen is supplied by a microporous aeration system. During the initial startup phase, the initial flocculent sludge concentration in the reactor is 7000 mg / L. The sludge-water mixture sequentially passes through a fiber packing frame (1% of the reactor's effective volume), a polyethylene packing frame (25% of the reactor's effective volume), and a polyurethane packing frame (3% of the reactor's effective volume) to complete denitrification. Then, it undergoes sludge-water separation through an internal separator. A portion of the separated wastewater is sent back to the inlet through an effluent return system, while the remainder is discharged. The return wastewater flow rate is 100% of the influent flow rate.

[0071] When the process is running stably, the mass concentration of flocculent sludge in the reactor is 1400 mg / L. Experimental results show that after the process stabilizes, the nitrogen removal rate reaches approximately 90%, and the effluent NH4... + -N is below 40 mg / L, and total nitrogen is below 70 mg / L.

[0072] After running the process for 100 days, the mass concentration of flocculent sludge in the reactor was 2500 mg / L. 0.5% of the polyurethane packing was removed and replaced with blank polyurethane packing. After the process stabilized, experimental results showed that the nitrogen removal rate reached approximately 90% after replacing the packing, and the effluent NH4... +-N is below 40 mg / L, and total nitrogen is below 70 mg / L. Therefore, continuous and efficient nitrogen removal can be achieved by replacing the packing material.

[0073] Example 4

[0074] The difference between Example 4 and Example 1 is that the fiber packing frame occupies 5% of the effective volume of the reactor, the polyethylene packing frame occupies 20% of the effective volume of the reactor, and the polyurethane packing frame occupies 3% of the effective volume of the reactor.

[0075] The experimental results show that after the process stabilizes, the nitrogen removal rate reaches about 85%, and the effluent NH4 content is reduced. + -N is less than 10 mg / L, and total nitrogen is less than 15 mg / L.

[0076] Comparative Example 1

[0077] The difference between Comparative Example 1 and Example 1 is that only a fiber packing frame is installed in the reactor, and the fiber packing frame occupies 26% of the effective volume of the reactor.

[0078] The experimental results show that after the process stabilizes, the nitrogen removal rate reaches about 60%, and the effluent NH4 content is reduced. + -N is below 20 mg / L, and total nitrogen is below 40 mg / L.

[0079] Comparative Example 2

[0080] The difference between Comparative Example 2 and Example 1 is that only a polyethylene packing frame is installed in the reactor, and the polyethylene packing frame occupies 26% of the effective volume of the reactor.

[0081] The experimental results show that after the process stabilizes, the nitrogen removal rate reaches about 75%, and the effluent NH4 content is reduced. + -N is less than 15 mg / L, and total nitrogen is less than 25 mg / L.

[0082] Comparative Example 3

[0083] The difference between Comparative Example 3 and Example 1 is that only a polyurethane packing frame is installed in the reactor, and the polyurethane packing frame occupies 26% of the effective volume of the reactor.

[0084] The experimental results show that after the process stabilizes, the nitrogen removal rate reaches about 65%, and the effluent NH4 content is reduced. + -N is below 18 mg / L, and total nitrogen is below 35 mg / L.

[0085] Comparative Example 4

[0086] The difference between Comparative Example 4 and Example 1 is that the mud-water mixture passes sequentially through a fiber packing frame accounting for 1% of the effective volume of the reactor, a polyurethane packing frame accounting for 20% of the effective volume of the reactor, and a polyethylene packing frame accounting for 5% of the effective volume of the reactor.

[0087] The experimental results show that after the process stabilizes, the nitrogen removal rate reaches about 68%, and the effluent NH4 content is reduced. + -N is below 20 mg / L, and total nitrogen is below 32 mg / L.

[0088] Comparative Example 5

[0089] The difference between Comparative Example 5 and Example 1 is that the mud-water mixture passes sequentially through a polyethylene packing frame accounting for 1% of the effective volume of the reactor, a fiber packing frame accounting for 20% of the effective volume of the reactor, and a polyurethane packing frame accounting for 5% of the effective volume of the reactor.

[0090] The experimental results show that after the process stabilizes, the nitrogen removal rate reaches about 62%, and the effluent NH4 content is reduced. + -N is below 25 mg / L, and total nitrogen is below 38 mg / L.

[0091] Comparative Example 6

[0092] The difference between Comparative Example 6 and Example 1 is that the mud-water mixture passes sequentially through a polyethylene packing frame accounting for 1% of the effective volume of the reactor, a polyurethane packing frame accounting for 20% of the effective volume of the reactor, and a fiber packing frame accounting for 5% of the effective volume of the reactor.

[0093] The experimental results show that after the process stabilizes, the nitrogen removal rate reaches about 66%, and the effluent NH4 content is reduced. + -N is below 22 mg / L, and total nitrogen is below 34 mg / L.

[0094] Comparative Example 7

[0095] The difference between Comparative Example 7 and Example 1 is that the mud-water mixture passes sequentially through a polyurethane packing frame accounting for 1% of the effective volume of the reactor, a fiber packing frame accounting for 20% of the effective volume of the reactor, and a polyethylene packing frame accounting for 5% of the effective volume of the reactor.

[0096] The experimental results show that after the process stabilizes, the nitrogen removal rate reaches approximately 64%, and the effluent NH4 content is reduced. + -N is below 23 mg / L, and total nitrogen is below 36 mg / L.

[0097] Comparative Example 8

[0098] The difference between Comparative Example 8 and Example 1 is that the mud-water mixture passes sequentially through a polyurethane packing frame accounting for 1% of the effective volume of the reactor, a polyethylene packing frame accounting for 20% of the effective volume of the reactor, and a fiber packing frame accounting for 5% of the effective volume of the reactor.

[0099] The experimental results show that after the process is stabilized, the nitrogen removal rate reaches about 80%, and the effluent NH4 content is reduced. +-N is less than 5 mg / L, and total nitrogen is less than 20 mg / L.

[0100] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0101] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A PNA-IFAS process, characterized in that, The PNA-IFAS process includes the following steps: The sludge-water mixture obtained by mixing wastewater with flocculent sludge with PNA activity is denitrified by sequentially passing through fiber packing, polyethylene packing and polyurethane packing under aeration and oxygenation conditions, and then the sludge-water mixture is separated to obtain wastewater that meets the discharge standards. In the effective volume of the reactor, the volume percentage of the fiber filler is 1%-5%, the volume percentage of the polyethylene filler is 10%-25%, and the volume percentage of the polyurethane filler is 1%-5%, with the volume percentage of the polyurethane filler being greater than that of the fiber filler.

2. The PNA-IFAS process according to claim 1, characterized in that, The mass concentration of flocculent sludge in the mud-water mixture is 5000 mg / L-8000 mg / L.

3. The PNA-IFAS process according to claim 1 or 2, characterized in that, In the denitrification system, the mass concentration of flocculent sludge is 1000 mg / L-1500 mg / L.

4. The PNA-IFAS process according to claim 3, characterized in that, When the mass concentration of flocculent sludge in the denitrification system increases from 1000mg / L-1500mg / L to over 2000mg / L, some of the packing material will be replaced with blank packing material.

5. The PNA-IFAS process according to claim 4, characterized in that, The volume of the blank packing to be replaced is 0.05%-2% of the total volume of the same type of packing.

6. The PNA-IFAS process according to claim 1, characterized in that, After the mud and water are separated, some of the wastewater is recycled for denitrification.

7. The PNA-IFAS process according to claim 6, characterized in that, The wastewater flow rate for denitrification is 100%-300% of the influent flow rate.

8. An apparatus for the PNA-IFAS process as described in any one of claims 1-7, characterized in that, The device includes an inlet, an integrated continuous flow PNA reactor, and an outlet. The integrated continuous flow PNA reactor includes a microporous aeration system, a fiber packing frame, a polyethylene packing frame, and a polyurethane packing frame arranged sequentially in the direction of water flow, and a built-in separator located at the outlet.

9. The apparatus according to claim 8, characterized in that, The integrated continuous flow PNA reactor also includes a submersible agitator; And / or, the device further includes a water return system disposed between the inlet and the outlet; And / or, the device further includes a lifting device and a mounting slot, wherein the fiber packing frame, the polyethylene packing frame and the polyurethane packing frame are all fixed in the mounting slot, and the lifting device is used to control the movement of any packing frame.

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