PNA-IFAS process and apparatus therefor

Abstract

The invention relates to a PNA-IFAS process and a device thereof. The PNA-IFAS process comprises the following steps: mixing sewage with floc sludge with PNA activity to obtain a mud-water mixture, under aeration and oxygenation conditions, enabling the mud-water mixture to sequentially pass through a fiber filler, a polyethylene filler and a polyurethane filler to complete denitrification, and then performing mud-water separation to obtain sewage meeting the discharge standard; wherein 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%. According to the PNA-IFAS process disclosed by the invention, by adding the floc sludge with PNA activity and cooperatively controlling the proportion and sequence of the mixed filler, the biomass in a reactor system is not easy to lose, the starting time is short, and continuous and efficient nitrogen removal of the PNA-IFAS system is realized.

Description

Technical Field

[0001] The invention relates to the technical field of sewage biological treatment, in particular to a PNA-IFAS process and a device thereof. Background Art

[0002] The presence of nitrogen pollutants in sewage, especially high concentrations of ammonia nitrogen, poses a serious threat to the water environment and human health. Traditional biological denitrification processes usually rely on a complete nitrification-denitrification process, which requires not only high aeration, but also a large amount of carbon source addition, accompanied by high energy and material consumption. Therefore, the development of efficient and low-cost nitrogen removal technology has become a research hotspot in the field of sewage treatment.

[0003] The short-range nitrification-anaerobic ammonium oxidation (PNA) technology achieves nitrogen removal by partially oxidizing ammonia nitrogen to nitrite, and then using anaerobic ammonium oxidizing bacteria (Anammox) to directly convert ammonia nitrogen and nitrite into nitrogen gas. Compared with the traditional nitrification-denitrification process, PNA technology has significant advantages such as saving aeration energy consumption, no need for external carbon source, and low sludge production. It is especially suitable for the treatment of high ammonia nitrogen wastewater.

[0004] The IFAS (Insulated Film Aquaculture System) combines the advantages of flocculent sludge and biofilm. By coexisting suspended flocculent sludge and attached biofilm in the reactor, the biomass and biodiversity are significantly increased. This design not only improves the treatment efficiency of the system, but also enhances the system's tolerance to water quality fluctuations. Combining the IFAS process with the PNA process can further optimize the nitrogen removal effect, especially under complex conditions such as low temperature and low carbon / nitrogen ratio.

[0005] The PNA-IFAS process is widely used in actual engineering projects. However, during the startup phase, the process has a long initial startup time, which is prone to sludge loss and biofilm shedding. As the operating time increases, the biofilm thickness increases, causing increased mass transfer resistance and reduced denitrification efficiency, which poses challenges in achieving continuous and efficient denitrification. Summary of the invention

[0006] Based on this, it is necessary to provide a PNA-IFAS process and a device thereof to address the above problems; the PNA-IFAS process described in the present invention adds flocculent sludge with PNA activity and synergistically controls the proportion and sequence of mixed fillers, 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 comprises the following steps:

[0008] The sewage is mixed with the floc sludge having PNA activity to obtain a mud-water mixture, and under aeration and oxygenation conditions, the mud-water mixture is sequentially passed through a fiber filler, a polyethylene filler and a polyurethane filler to complete denitrification, and then the mud-water separation is performed to obtain sewage that meets the discharge standards;

[0009] Wherein, 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%.

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

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

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

[0013] In one of the embodiments, when the mass concentration of flocculent sludge in the denitrification system increases from 1000 mg / L-1500 mg / L to above 2000 mg / L, part of the filler is replaced with the same blank filler.

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

[0015] In one of the embodiments, after the sludge and water are separated, part of the wastewater is recycled for denitrification.

[0016] In one of the embodiments, the wastewater flow rate circulating for denitrification is 100%-300% of the inlet water flow rate.

[0017] A device used in the PNA-IFAS process as described above comprises a water inlet, an integrated continuous flow PNA reactor and a water outlet, wherein the integrated continuous flow PNA reactor comprises a microporous aeration system, a fiber filler rack, a polyethylene filler rack and a polyurethane filler rack arranged in sequence according to the water flow direction, and a built-in separator arranged at the water outlet.

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

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

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

[0021] In the PNA-IFAS process described in the present invention, floc sludge with PNA activity is inoculated, a mixed blank filler is used as a carrier to form a biofilm, and sewage passes through a fiber filler, a polyethylene filler, and a polyurethane filler in a specific volume ratio in sequence, thereby achieving a better biofilm effect, ensuring that the overall biofilm thickness is similar and the concentration gradient treatment efficiency corresponding to each adaptation is improved, greatly shortening the start-up time of the PNA-IFAS system reaction, and utilizing the floc sludge and aerobic ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria in the biofilm to efficiently and synergistically complete a short-range nitrification and anaerobic ammonia oxidation reaction, remove nitrogen from sewage, and achieve continuous and efficient denitrification of the PNA-IFAS system.

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

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 Schematic diagram of the structure of the PNA-IFAS device.

[0025] Among them, 1. water inlet; 2. integrated continuous flow PNA reactor; 3. microporous aeration system; 4. submersible agitator; 5. fiber filler rack; 6. polyethylene filler rack; 7. polyurethane filler rack; 8. built-in separator; 9. water outlet reflux system; 10. water outlet; 11. lifting device; 12. installation slot. DETAILED DESCRIPTION

[0026] For ease of understanding of the present invention, the present invention 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. On the contrary, the purpose of providing these embodiments or examples is to make the understanding of the disclosure of the present invention more thorough and comprehensive.

[0027] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific implementation methods or embodiments, and are not intended to limit the present invention. The optional scope of the term "and / or" used herein includes any one of two or more related listed items, and also includes any and all combinations of related listed items, and the combinations include any two related listed items, any more related listed items, or all related listed items.

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

[0029] The mud-water mixture obtained by mixing sewage with floc sludge having PNA activity is passed through fiber filler, polyethylene filler and polyurethane filler in sequence under aeration and oxygenation conditions to complete denitrification, and then the mud-water separation is performed to obtain sewage that meets the discharge standards.

[0030] Wherein, 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%.

[0031] In the PNA-IFAS process described in the present invention, floc sludge with PNA activity is inoculated, a mixed blank filler is used as a carrier to form a biofilm, and sewage passes through a fiber filler, a polyethylene filler, and a polyurethane filler in a specific volume ratio in sequence, thereby achieving a better biofilm effect, ensuring that the overall biofilm thickness is similar and the concentration gradient treatment efficiency corresponding to each adaptation is improved, greatly shortening the start-up time of the PNA-IFAS system reaction, and utilizing the floc sludge and aerobic ammonia oxidizing bacteria and anaerobic ammonia oxidizing bacteria in the biofilm to efficiently and synergistically complete a short-range nitrification and anaerobic ammonia oxidation reaction, remove nitrogen from sewage, and achieve continuous and efficient denitrification of the PNA-IFAS system.

[0032] Specifically, the fiber filler has a high biofilm formation rate based on its unique high aspect ratio fibrous structure, which is beneficial to the removal of organic matter and suspended solids in sewage, provides better reaction conditions for the subsequent polyethylene filler biofilm, and reduces the reaction startup time. Among them, the fiber filler is preferably a soft fiber filler.

[0033] Although the biofilm formation rate of polyethylene filler is lower than that of fiber filler, the biofilm is stably attached to it and is not easy to fall off. The biofilm provides an anaerobic ammonium oxidizing bacteria with an anoxic microenvironment. Anaerobic ammonium oxidizing bacteria convert ammonia nitrogen and nitrite nitrogen into nitrogen gas under anoxic conditions, thereby achieving a better denitrification effect, improving denitrification efficiency, and reducing the reaction startup time.

[0034] The polyurethane filler has a unique porous structure, which is conducive to absorbing microorganisms detached from the fiber filler and polyethylene filler, ensuring that the biomass in the system is not easily lost, thereby making the denitrification efficiency continuously stable.

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

[0036] Preferably, the volume percentage of the polyurethane filler is greater than the volume percentage of the fiber filler, which is beneficial to further improve the sustained stability of the denitrification efficiency.

[0037] It should be noted that at the beginning of the reaction, the mass concentration of the flocculent sludge in the reactor is the highest; as the reaction proceeds, the flocculent sludge is gradually transferred to the filler, causing the filler to form a biofilm. In a stable denitrification system, the mass concentration of the flocculent sludge is reduced by about 80%-90% compared with the initial concentration; as the biofilm in the filler continues to increase, when the load of the biofilm in the filler is oversaturated, the flocculent sludge on the filler gradually returns to the water, causing the mass concentration of the flocculent sludge to increase compared to the mass concentration of the flocculent sludge in the 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 point value among 5000 mg / L, 6000 mg / L, 7000 mg / L, 8000 mg / L or any range value between two of them.

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

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

[0041] Preferably, the volume of the replaced blank filler is 0.05%-2% of the total volume of the same filler, including but not limited to any value among 0.05%, 0.1%, 0.5%, 0.8%, 1%, 1.5%, 2% or any range between two values.

[0042] Through mud-water separation, the sludge can be retained in the reactor, and together with the polyurethane filler, it can ensure that the biomass in the system is not easily lost, maintaining the sludge concentration in the reactor, thereby making the denitrification efficiency continuously stable.

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

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

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

[0046] Combination Figure 1 As shown, a device for the PNA-IFAS process as described above provided by the present invention includes a water inlet 1, an integrated continuous flow PNA reactor 2 and a water outlet 10, wherein the integrated continuous flow PNA reactor 2 includes a microporous aeration system 3, a fiber filler frame 5, a polyethylene filler frame 6 and a polyurethane filler frame 7 arranged in sequence according to the water flow direction, and a built-in separator 8 arranged at the water outlet.

[0047] It should be noted that the device described in the present invention does not limit the mixing method of sewage and floc sludge with PNA activity. The sewage and floc sludge with PNA activity can be first mixed to form a mud-water mixture, and then the mud-water mixture is introduced from the water inlet 1. The floc sludge can also be pre-set in the integrated continuous flow PNA reactor 2, and then the sewage can be introduced from the water inlet 1 to mix the sewage and floc sludge in the integrated continuous flow PNA reactor 2.

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

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

[0050] Preferably, the microporous aeration system 3 is distributed at the bottom of the fiber filler frame 5, the polyethylene filler frame 6 and the polyurethane filler frame 7, which is conducive to uniformly providing oxygen and ensuring a continuous and stable denitrification process.

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

[0052] It should be noted that the fiber packing frame 5, the polyethylene packing frame 6 and the polyurethane packing frame 7 may be independent cells or an integral cell, and the present invention does not limit this. When the packing frames are independent cells, the cells of different packing frames can be connected through holes or pipes to ensure that water flows through.

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

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

[0055] In one embodiment, the device further comprises a water return system 9 disposed between the water inlet 1 and the water outlet 10, so that part of the sewage after the mud and water separation is circulated for denitrification.

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

[0057] The device used in the PNA-IFAS process of the present invention has a high nitrogen removal load, occupies a small area, and has high feasibility for engineering application.

[0058] The PNA-IFAS process and its device will be further described below by the following specific examples. However, it will be understood by those skilled in the art that the following examples are only used to illustrate the present invention and should not be considered as limiting the scope of the present invention. If no specific conditions are specified in the examples, the conditions are carried out according to conventional conditions or conditions recommended by the manufacturer. If the manufacturer of the reagents or instruments used is not specified, they are all conventional products that can be obtained commercially.

[0059] Example 1

[0060] The treatment object is artificial synthetic wastewater, and the specific water quality is as follows: COD is 100mg / L-200mg / L, NH4 + -N is 100mg / L-200mg / L, NO3 - -N≤5mg / L, NO2 - -N≤5mg / L.

[0061] The synthetic wastewater is introduced into the integrated continuous flow PNA reactor through the water inlet, and oxygen is supplied by the microporous aeration system. At the initial start-up, the mass concentration of the initial flocculent sludge in the reactor is 6000mg / L. The mud-water mixture is successively denitrified by passing through the fiber filler rack that accounts for 1% of the effective volume of the reactor, the polyethylene filler rack that accounts for 20% of the effective volume of the reactor, and the polyurethane filler rack that accounts for 5% of the effective volume of the reactor, and then the mud and water are separated by the built-in separator. Part of the sewage obtained after separation is sent to the water inlet through the effluent return system, and the remaining part is discharged, among which the flow rate of the returned part of the sewage is 200% of the inlet flow rate.

[0062] The test results show that after the process runs stably, the COD removal rate reaches more than 90%, the nitrogen removal rate reaches about 85%, and the effluent NH4 + -N is lower than 5mg / L and total nitrogen is lower than 15mg / L.

[0063] Example 2

[0064] The landfill leachate is treated as the object, and the specific water quality is as follows: COD is 2000mg / L-3000mg / L, NH4 + -N is 1800mg / L-2000mg / L, NO3 - -N≤2mg / L, NO2 - -N≤0.5mg / L.

[0065] The landfill leachate is introduced into the integrated continuous flow PNA reactor through the water inlet, and oxygen is supplied by the microporous aeration system. At the initial start-up, the mass concentration of the initial flocculent sludge in the reactor is 8000mg / L. The mud-water mixture is successively denitrified by passing through the fiber filler rack that accounts for 3% of the effective volume of the reactor, the polyethylene filler rack that accounts for 20% of the effective volume of the reactor, and the polyurethane filler rack that accounts for 5% of the effective volume of the reactor, and then the mud and water are separated by the built-in separator. Part of the sewage obtained after separation is sent to the water inlet through the effluent return system, and the remaining part is discharged, among which the flow rate of the returned part of the sewage is 100% of the inlet flow rate.

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

[0067] The process was run to the 200th day, the mass concentration of flocculent sludge in the reactor was 2200 mg / L, and the removal rate was reduced to about 85%. 1% of the polyethylene filler was removed and replaced with blank polyethylene filler. After 30 days of operation, the test results showed that after the filler was replaced, the nitrogen removal rate reached about 90%, and the effluent NH4 + -N is lower than 30mg / L, and total nitrogen is lower than 50mg / L. Therefore, continuous and efficient denitrification can be achieved by replacing the filler.

[0068] Example 3

[0069] The kitchen wastewater is treated as the object, and the specific water quality is as follows: COD is 2000mg / L-3000mg / L, NH4 + -N is 3000mg / L-4000mg / L, NO3 - -N≤10mg / L, NO2 - -N≤5mg / L.

[0070] The kitchen wastewater is introduced into the integrated continuous flow PNA reactor through the water inlet, and oxygen is supplied by the microporous aeration system. At the initial start-up, the mass concentration of the initial flocculent sludge in the reactor is 7000mg / L. The mud-water mixture passes through the fiber filler rack that accounts for 1% of the effective volume of the reactor, the polyethylene filler rack that accounts for 25% of the effective volume of the reactor, and the polyurethane filler rack that accounts for 3% of the effective volume of the reactor to complete the denitrification, and then the mud and water are separated by the built-in separator. Part of the sewage obtained after separation is sent to the water inlet through the effluent return system, and the remaining part is discharged, among which the flow rate of the returned part of the sewage is 100% of the inlet flow rate.

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

[0072] The process was run until the 100th day, when the mass concentration of flocculent sludge in the reactor was 2500 mg / L, 0.5% polyurethane filler was removed and replaced with blank polyurethane filler. After the process was stable, the test results showed that after the filler was replaced, the nitrogen removal rate reached about 90%, and the effluent NH4 +-N is lower than 40mg / L and total nitrogen is lower than 70mg / L. Therefore, continuous and efficient denitrification can be achieved by replacing the filler.

[0073] Example 4

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

[0075] The test results show that after the process runs stably, the nitrogen removal rate reaches about 85%, and the effluent NH4 + -N is lower than 10mg / L and total nitrogen is lower than 15mg / L.

[0076] Comparative Example 1

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

[0078] The test results show that after the process runs stably, the nitrogen removal rate reaches about 60%, and the effluent NH4 + -N is lower than 20mg / L and total nitrogen is lower than 40mg / L.

[0079] Comparative Example 2

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

[0081] The test results show that after the process runs stably, the nitrogen removal rate reaches about 75%, and the effluent NH4 + -N is lower than 15mg / L and total nitrogen is lower than 25mg / L.

[0082] Comparative Example 3

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

[0084] The test results show that after the process runs stably, the nitrogen removal rate reaches about 65%, and the effluent NH4 + -N is lower than 18mg / L and total nitrogen is lower than 35mg / L.

[0085] Comparative Example 4

[0086] The difference between Comparative Example 4 and Example 1 is that the mud-water mixture passes through a fiber packing rack occupying 1% of the effective volume of the reactor, a polyurethane packing rack occupying 20% ​​of the effective volume of the reactor, and a polyethylene packing rack occupying 5% of the effective volume of the reactor in sequence.

[0087] The test results show that after the process runs stably, the nitrogen removal rate reaches about 68%, and the effluent NH4 + -N is lower than 20mg / L and total nitrogen is lower than 32mg / L.

[0088] Comparative Example 5

[0089] The difference between Comparative Example 5 and Example 1 is that the mud-water mixture passes through a polyethylene packing rack occupying 1% of the effective volume of the reactor, a fiber packing rack occupying 20% ​​of the effective volume of the reactor, and a polyurethane packing rack occupying 5% of the effective volume of the reactor in sequence.

[0090] The test results show that after the process runs stably, the nitrogen removal rate reaches about 62%, and the effluent NH4 + -N is lower than 25mg / L and total nitrogen is lower than 38mg / L.

[0091] Comparative Example 6

[0092] The difference between Comparative Example 6 and Example 1 is that the mud-water mixture passes through a polyethylene packing rack occupying 1% of the effective volume of the reactor, a polyurethane packing rack occupying 20% ​​of the effective volume of the reactor, and a fiber packing rack occupying 5% of the effective volume of the reactor in sequence.

[0093] The test results show that after the process runs stably, the nitrogen removal rate reaches about 66%, and the effluent NH4 + -N is lower than 22mg / L and total nitrogen is lower than 34mg / L.

[0094] Comparative Example 7

[0095] The difference between Comparative Example 7 and Example 1 is that the mud-water mixture passes through a polyurethane filler rack occupying 1% of the effective volume of the reactor, a fiber filler rack occupying 20% ​​of the effective volume of the reactor, and a polyethylene filler rack occupying 5% of the effective volume of the reactor in sequence.

[0096] The test results show that after the process runs stably, the nitrogen removal rate reaches about 64%, and the effluent NH4 + -N is lower than 23mg / L and total nitrogen is lower than 36mg / L.

[0097] Comparative Example 8

[0098] The difference between Comparative Example 8 and Example 1 is that the mud-water mixture passes through a polyurethane packing rack occupying 1% of the effective volume of the reactor, a polyethylene packing rack occupying 20% ​​of the effective volume of the reactor, and a fiber packing rack occupying 5% of the effective volume of the reactor in sequence.

[0099] The test results show that after the process runs stably, the nitrogen removal rate reaches about 80%, and the effluent NH4 +-N is lower than 5mg / L and total nitrogen is lower than 20mg / L.

[0100] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described 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 above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A PNA-IFAS process, characterized in that: The PNA-IFAS process comprises the following steps: The sewage is mixed with the floc sludge having PNA activity to obtain a mud-water mixture, and under aeration and oxygenation conditions, the mud-water mixture is sequentially passed through a fiber filler, a polyethylene filler and a polyurethane filler to complete denitrification, and then the mud-water separation is performed to obtain sewage that meets the discharge standards; Wherein, 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%.

2. The PNA-IFAS process according to claim 1, characterized in that The volume percentage of the polyurethane filler is greater than the volume percentage of the fiber filler.

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

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

5. The PNA-IFAS process according to claim 4, characterized in that When the mass concentration of flocculent sludge in the denitrification system increases from 1000 mg / L-1500 mg / L to above 2000 mg / L, part of the filler is replaced with blank filler.

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

7. The PNA-IFAS process according to claim 1, characterized in that After mud and water separation, part of the sewage is recycled for denitrification.

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

9. A device for use in the PNA-IFAS process according to any one of claims 1 to 8, characterized in that: The device includes a water inlet, an integrated continuous flow PNA reactor and a water outlet, wherein the integrated continuous flow PNA reactor includes a microporous aeration system, a fiber filler rack, a polyethylene filler rack and a polyurethane filler rack arranged in sequence according to the water flow direction, and a built-in separator arranged at the water outlet.

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

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