AOA treatment method and device for high-organic-nitrogen low-temperature continuous flow

Abstract

The invention provides a high organic nitrogen low temperature continuous flow AOA treatment method and device, and belongs to the technical field of wastewater treatment.The device comprises a hydrolytic acidification zone, an anaerobic zone, an anaerobic and aerobic variable zone, an aerobic zone, an aerobic and anoxic variable zone, an anoxic zone, an anoxic and aerobic variable zone and a secondary sedimentation tank which are connected in sequence; the secondary sedimentation tank is connected with the anaerobic zone through a first sludge return pipe and is connected with the anoxic zone through a second sludge return pipe; the external carbon source storage tank is connected with the anoxic zone. When the device is used for treating wastewater, a necessary internal carbon source can be stored for subsequent anoxic denitrification, the contradiction of insufficient external carbon sources is effectively relieved, stable nitrite nitrogen matrix supply is also provided for anaerobic ammonium oxidation bacteria, under the dual pressure of low temperature and water quality fluctuation, the treatment performance of the device can be stabilized, and the treatment effect of the device is improved. The total nitrogen is efficiently removed under the condition that a carbon source is not added, and the low-temperature resistance is improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of wastewater treatment, and particularly relates to a high-organic-nitrogen low-temperature continuous-flow AOA treatment method and device. BACKGROUND

[0002] With water resource shortage and limited water environment capacity, the discharge standards for sewage treatment, especially the nitrogen and phosphorus indicators, are becoming increasingly stringent. Some municipal sewage treatment plants are mixed with industrial wastewater, which has three notable and interrelated characteristics: high proportion of organic nitrogen, low carbon-nitrogen ratio, and low temperature in winter. The three factors together make the sewage treatment plants using traditional biological denitrification and phosphorus removal process face the dilemma of low efficiency, unstable operation, large carbon source dosage, and large sludge production, and urgent process upgrading is needed.

[0003] The A 2 O and multi-stage AO processes widely used in sewage treatment plants have certain drawbacks, such as inhibition of anaerobic phosphorus release by nitrate nitrogen carried by reflux sludge, destruction of anoxic denitrification environment by high dissolved oxygen carried by reflux nitrification liquid, and high reflux energy consumption, which makes it difficult for the effluent nitrogen and phosphorus to meet the standards.

[0004] The AOA (anaerobic-aerobic-anoxic) process, as an innovative variant of the double-sludge system, provides a new idea for solving the above problems by changing the order of the reaction zones. The aerobic section is placed after the anaerobic section and before the anoxic section, which has potential advantages: first, it allows phosphorus-accumulating bacteria to fully release phosphorus in the anaerobic zone and then absorb excess phosphorus in the first aerobic zone, achieving rapid phosphorus removal; second, the nitrate nitrogen produced in the aerobic zone can directly enter the subsequent anoxic zone for denitrification.

[0005] However, the current AOA process still faces many unsolved technical problems when directly applied to special water quality mixed with industrial wastewater, specifically as follows: (1) Under the background of high proportion of organic nitrogen, how to ensure efficient coupling of the ammoniation process of organic nitrogen and the nitrification / denitrification process in terms of time and space, and avoid the denitrification bottleneck caused by delayed ammoniation.

[0006] (2) Under the condition of low carbon-nitrogen ratio, how to accurately regulate the working conditions to enrich denitrifying phosphorus-accumulating bacteria (DPAOs) and denitrifying glycogen-accumulating bacteria (DGAOs), so that they can use nitrate nitrogen as an electron acceptor to simultaneously complete denitrification and phosphorus removal, achieve "one-carbon dual-use" of internal carbon source, and thus alleviate the carbon source competition contradiction.

[0007] (3) How to enhance the competitive advantage and metabolic activity of functional bacteria (especially DPAOs) at low temperature, and improve the overall low-temperature performance of the system.

[0008] Therefore, existing technologies lack an AOA process that can specifically address the three core contradictions of wastewater: "high organic nitrogen content, low carbon-nitrogen ratio, and low temperature". Summary of the Invention

[0009] This invention provides a method and apparatus for high-organic-nitrogen, low-temperature, continuous flow AOA treatment based on short-range nitrifying bacteria encapsulation, aiming to resolve the contradictions in wastewater treatment with high organic nitrogen content, low carbon-nitrogen ratio, low temperature, and industrial wastewater contamination.

[0010] The issues include the denitrification bottleneck caused by delayed ammoniation under high organic nitrogen ratio conditions, the contradiction of carbon source competition under low carbon-nitrogen ratio conditions, and the problem of poor metabolic activity in low-temperature wastewater.

[0011] Firstly, to achieve the above objectives, the technical solution adopted by the present invention is: to provide a high-organic-nitrogen, low-temperature, continuous-flow AOA treatment method, the method comprising: The low-temperature wastewater is sequentially treated through a hydrolysis acidification zone, an anaerobic zone, an anaerobic-aerobic variable zone, an aerobic zone, an aerobic-anoxic variable zone, anoxic zone, and an anoxic-aerobic variable zone to form the final treated mixed liquid, which enters the secondary sedimentation tank for sedimentation and separation. The upper clarified water meets the discharge standards and is discharged, while the sludge deposited at the bottom of the secondary sedimentation tank is reused. The first treated mixed liquor obtained after the low-temperature wastewater undergoes organic nitrogen decomposition and ammoniation in the hydrolysis acidification zone enters the anaerobic zone. The sludge pumped from the secondary sedimentation tank enters the anaerobic zone simultaneously through the first sludge return pipe. The first treated mixed liquor, the simultaneously entering sludge, and the suspended biological packing material added to the anaerobic zone are mixed. Under anoxic conditions, the anaerobic ammonia-oxidizing bacteria enriched in the anaerobic zone convert ammonia nitrogen into nitrogen gas to achieve denitrification. The enriched denitrifying polyphosphate-accumulating bacteria convert ammonia nitrogen into small molecule volatile fatty acids (VFAs) and synthesize internal carbon source (PHA), releasing phosphates to achieve denitrification and phosphorus removal, thus obtaining the second treated mixed liquor. The second treatment mixture, after passing through the anaerobic-aerobic variable zone, yields the third treatment mixture, which then enters the aerobic zone to absorb phosphorus. Simultaneously, ammonia nitrogen is oxidized to nitrite and nitrate nitrogen. Under low dissolved oxygen conditions, short-range nitrifying and denitrifying bacteria are enriched through the embedded bodies in the aerobic zone to enhance nitrogen and phosphorus removal under low-temperature conditions, resulting in the fourth treatment mixture. The fourth treatment mixture containing a large amount of nitrate nitrogen / nitrite nitrogen enters the aerobic-anoxic variable zone. In the anoxic mode, some nitrogen is removed through simultaneous nitrification and denitrification to obtain the fifth treatment mixture. The fifth treatment mixture is then mixed with sludge that is simultaneously drawn from the secondary sedimentation tank and enters through the second sludge return pipe in the anoxic zone. The nitrate nitrogen is converted into nitrogen gas through a long anoxic mode to achieve denitrification and obtain the sixth treatment mixture. The sixth treatment mixture passes through the anoxic-aerobic variable zone, and the resulting final treatment mixture meets the emission standards.

[0012] With reference to the first aspect, in an implementable mode, when the low-temperature wastewater is sewage under industrial wastewater stress: The total nitrogen in the low-temperature wastewater is 50-70 mg / L, the percentage of organic nitrogen to total nitrogen is 10%-20%, the C / N ratio is 4-7, and the water temperature is <15°C.

[0013] With reference to the first aspect, in an implementable mode, the sludge reflux ratio synchronously entering the anaerobic zone is 70%-120%, and the reflux sludge concentration is 4000-5500 mg / L; the filling ratio of the suspended biological filler added in the anaerobic zone is 20%-30%.

[0014] With reference to the first aspect, in an implementable mode, the anaerobic-aerobic variable zone is operated in an aerobic mode, and the dissolved oxygen is 1-4 mg / L to strengthen complete nitrification.

[0015] With reference to the first aspect, in an implementable mode, the embedding body comprises polyvinyl alcohol (PVA) and sodium alginate (SA), and is fixed in the aerobic zone by silk screen after being mixed and solidified, and the filling ratio is 30%-40%.

[0016] With reference to the first aspect, in an implementable mode, the sludge synchronously entering the anoxic zone has a sludge reflux ratio of 70%-120% and a reflux sludge concentration of 4000-5500 mg / L.

[0017] With reference to the first aspect, in an implementable mode, the anoxic-aerobic variable zone is operated in an aerobic mode, and the dissolved oxygen is set to 1-1.5 mg / L to strengthen nitrification and deep oxidation of organic matter, so that the effluent meets the discharge standard: ammonia nitrogen <1.5 mg / L and COD <20 mg / L.

[0018] With reference to the first aspect, in an implementable mode, when the low-temperature wastewater to be treated is under high total nitrogen load conditions of industrial wastewater stress: The total nitrogen is 70-100 mg / L, the percentage of organic nitrogen to total nitrogen is 10%-15%, the water temperature is <15°C, and the C / N ratio is 3-6; The sludge reflux ratio synchronously entering the anaerobic zone is 100%-150%, and the reflux sludge concentration is 4000-5500 mg / L; The anaerobic-aerobic variable zone is operated in an anaerobic mode to prolong the anaerobic zone for strengthening of internal carbon source synthesis and phosphorus release; The sludge reflux ratio synchronously entering the anoxic zone is 100%-150%, and the reflux sludge concentration is 4000-5500 mg / L.

[0019] With reference to the first aspect, in an implementable mode, when the low-temperature wastewater is under low load and low C / N ratio conditions of water quantity impact: Total nitrogen is 30-40 mg / L, water temperature <15℃, C / N is 3-4; In the anoxic zone, a small amount of external carbon source is added through an external carbon source tank connected by a carbon source adding pump, 1 mgN is added with 1-3 mgCOD equivalent carbon source, and the carbon source is maintained stable; when the nitrate concentration NO3 - The carbon source adding pump is started when NO3 - The carbon source adding pump is closed when NO3 The anoxic and aerobic variable zone is operated in an anoxic mode, so that the anoxic time is prolonged, the activity of denitrifying bacteria is enhanced, and nitrogen is removed; According to the ammonia nitrogen concentration of the effluent of the anoxic and aerobic variable zone, the setting range of DO is adjusted: when the ammonia nitrogen concentration NH4 + When NH4 + When NH4 + When NH4

[0020] In the second aspect, the embodiment of the present application also provides a device for the high-organic-nitrogen low-temperature continuous-flow AOA treatment method, which comprises, in sequence, a hydrolysis acidification zone, an anaerobic zone, an anaerobic and aerobic variable zone, an aerobic zone, an aerobic and anoxic variable zone, an anoxic zone, an anoxic and aerobic variable zone and a secondary sedimentation tank; the secondary sedimentation tank is connected with the anaerobic zone through a first sludge return pipe and connected with the anoxic zone through a second sludge return pipe; The device further comprises an external carbon source tank connected with the anoxic zone.

[0021] Compared with the prior art, the high-organic-nitrogen low-temperature continuous-flow AOA treatment method and device provided by the present application have the beneficial effects that the treatment of wastewater by the present application can reserve the necessary internal carbon source for subsequent anoxic denitrification, effectively alleviate the contradiction of insufficient external carbon source, and provide stable nitrite nitrogen substrate for anaerobic ammonia oxidation bacteria, which is helpful to stabilize the treatment performance of the device under the double pressures of low temperature and water quality fluctuation, realizes efficient removal of total nitrogen under the condition of no additional carbon source, and improves the overall low-temperature resistance; meanwhile, the amount of external carbon source added and the sludge yield are reduced, which provides a new idea for actual wastewater treatment plants in terms of upgrading and reconstruction, energy consumption reduction and sludge yield reduction. BRIEF DESCRIPTION OF DRAWINGS

[0022] Figure 1 The present application provides a process flow structure schematic diagram of the high-organic-nitrogen low-temperature continuous-flow AOA treatment method; Explanation of reference signs: 1, water tank; 2, water inlet pump; 3, hydrolysis acidification zone; 4, anaerobic zone; 41, first anaerobic section; 42, second anaerobic section; 5, anaerobic-aerobic variable zone; 6, aerobic zone; 61, first aerobic section; 62, second aerobic section; 7, aerobic-anoxic variable zone; 8, anoxic zone; 81, first anoxic section; 82, second anoxic section; 83, third anoxic section; 84, fourth anoxic section; 85, fifth anoxic section; 86, sixth anoxic section; 9, anoxic-aerobic variable zone; 10, secondary sedimentation tank; 11, first sludge return pipe; 12, first sludge return pump; 13, second sludge return pipe; 14, second sludge return pump; 15, aeration head; 16, aeration pipe; 17, air blower; 18, PLC controller; 19, electric mixer; 20, online DO monitoring probe; 21, handheld dissolved oxygen meter; 22, suspended biological filler; 23, embedding body; 24, online water quality monitoring equipment; 25, online water quality multi-parameter monitoring equipment; 26, online monitoring nitrate probe; 27, online monitoring ammonia nitrogen probe; 28, external carbon source storage tank; 29, carbon source dosing pump; 30, computer; 31, sludge discharge pipe. DETAILED DESCRIPTION

[0023] In order to make the technical problems to be solved by the present application, technical solutions and beneficial effects clearer, the present application will be further described in detail below in combination with the drawings and examples. It should be understood that the specific examples described herein are only used to explain the present application and are not used to limit the present application.

[0024] In the claims, specification and above drawings of the present application, unless otherwise expressly defined, the terms such as "first", "second" or "third" are used only to distinguish different objects, and are not used to describe a specific order.

[0025] In the present application, "greater than", "less than", "exceed" and the like are understood as not including the number; "above", "below", "within" and the like are understood as including the number. In addition, in the description of the embodiments of the present application, the meaning of "multiple" is more than two (including two), and similar expressions related to "multiple" are also understood in this way, for example, "multiple groups", "multiple times" and the like, unless otherwise expressly defined.

[0026] For the convenience of understanding, the terms in the text are explained as follows: Anaerobic ammonia oxidation bacteria and denitrifying phosphorus accumulating organisms can synergize in wastewater treatment to achieve nitrogen and phosphorus removal functions. Both of them process nitrogen and phosphorus pollutants through different metabolic pathways, and the differences in their action mechanisms are as follows: Anaerobic ammonia oxidation bacteria: under anaerobic conditions, ammonia nitrogen is directly converted into nitrogen without the participation of organic matter, taking ammonia nitrogen as the electron donor and nitrite as the electron acceptor. Denitrifying phosphorus accumulating bacteria: in an anaerobic / anoxic alternating environment, denitrification and excess phosphorus accumulation are completed simultaneously by using nitrate or nitrite as the electron acceptor, and polyhydroxyalkanoate (PHA) is used as the internal carbon source. Chemical oxygen demand (COD) refers to the equivalent amount of oxygen consumed by the reduction of inorganic and organic matter (usually organic matter) in a water sample by chemical reaction, and is a very important indicator for judging whether the water environment is polluted.

[0027] DO value, i.e. dissolved oxygen content, refers to the concentration of molecular oxygen dissolved in water.

[0028] NH4 + -N represents the nitrogen content of ammonium ions.

[0029] Nitrifying bacteria are autotrophic aerobic bacteria, and their main function is to convert ammonia nitrogen (NH3-N) in wastewater into nitrite nitrogen (NO2 - -N), and further oxidize it into nitrate nitrogen (NO3 - -N), thereby removing ammonia nitrogen.

[0030] Please refer to Figure 1 , the high-organic-nitrogen low-temperature continuous-flow AOA treatment method provided by the present application will be described.

[0031] The overall process flow of the present application is as follows: the final treatment mixed liquor formed after the low-temperature wastewater sequentially passes through the hydrolysis acidification zone 3, the anaerobic zone 4, the anaerobic-aerobic variable zone 5, the aerobic zone 6, the aerobic-anoxic variable zone 7, the anoxic zone 8, the anoxic-aerobic variable zone 9, and then enters the secondary sedimentation tank 10 for sedimentation and separation, the upper clear water reaches the discharge standard and is discharged, and the sludge deposited at the bottom of the secondary sedimentation tank 10 is recycled.

[0032] In combination with Figure 1 understand the embodiments provided by the present application under multiple different conditions.

[0033] Example 1 Under the stress of industrial wastewater, the treatment process of low-temperature wastewater is as follows: Step 1, under the stress of industrial wastewater, the total nitrogen of the wastewater is 50-70 mg / L (organic nitrogen / total nitrogen: 10%-20%), the C / N is 4-7, and the water temperature is <15℃. The wastewater is introduced into the hydrolysis acidification zone 3 of the AOA device from the water tank 1 through the water pump 2, and the organic nitrogen is decomposed and ammoniated to obtain the first treatment mixed liquor.

[0034] The first treatment mixture enters the anaerobic zone 4, and the sludge drawn from the secondary sedimentation tank 10 through the first sludge return pump 12 enters the anaerobic zone 4 synchronously through the first sludge return pipe 11. The first treatment mixture, the synchronously added sludge, and the suspended biological filler 22 added to the anaerobic zone 4 are stirred and mixed by the electric agitator 19 inserted therein. The suspended biological filler 22 is added to provide a carrier for the growth of the bacterial flora and to create conditions for the enrichment of the anammox bacteria by using the internal anoxic structure. The enriched denitrifying phosphorus bacteria absorb small-molecule volatile fatty acids VFAs in the anaerobic zone 4, synthesize internal carbon source PHA, and release phosphate, thereby achieving denitrification and phosphorus removal and obtaining a second treatment mixture.

[0035] In the process, the sludge return ratio is 70% to 120%, the concentration of the return sludge is 4000 to 5500 mg / L, and the filling ratio of the suspended biological filler 22 added to the anaerobic zone 4 is 20% to 30%.

[0036] In step 2, the second treatment mixture enters the anaerobic-aerobic variable zone 5, which is operated in an aerobic mode with a dissolved oxygen of 1 to 4 mg / L. The anaerobic-aerobic variable zone is stirred and mixed by the electric agitator 19 inserted therein, thereby strengthening complete nitrification and obtaining a third treatment mixture.

[0037] When the third treatment mixture enters the aerobic zone 6, the embedded body 23 is added. The embedded body 23 is fixed in the aerobic zone 6 by a wire mesh, which limits the embedded body 23 to a certain range, effectively prevents clogging and loss of bacterial cells, and improves the impact resistance.

[0038] The main function of this section of the aerobic zone 6 is to oxidize ammonia nitrogen to nitrite nitrogen and nitrate nitrogen and to simultaneously absorb phosphorus, thereby obtaining a fourth treatment mixture. The dissolved oxygen in the aerobic zone 6 is controlled in the range of 0.5 to 1.5 mg / L, and the water temperature is less than 15℃. The anaerobic-aerobic variable zone is operated in an aerobic mode, the volume operated in the aerobic mode is increased, the embedded body 23 of the high-efficiency short-cut nitrification sludge is added, and the stable ammonia oxidation efficiency and certain short-cut nitrification effect are maintained under the conditions of low dissolved oxygen and low temperature.

[0039] The embedded body 23 includes polyvinyl alcohol PVA and sodium alginate SA, which are dissolved and mixed after being heated and stirred. The short-cut nitrification sludge is embedded in the embedded body 23. The obtained mixture is dropped into a crosslinking agent, and is gelled by physical and chemical methods to form spherical, granular, or block-shaped immobilized embedded bodies 23 with a density of 1 to 1.2 g / cm3. The filling ratio of the embedded body 23 as the filler is 30% to 40%, and the mass ratio of the short-cut nitrification sludge to the embedded body 23 is 20% to 30%.

[0040] In step 3, the fourth treatment mixture containing a large amount of nitrate nitrogen / nitrite nitrogen enters the aerobic-anoxic variable zone 7, which is operated in an anoxic mode. Part of the nitrogen is removed by simultaneous nitrification and denitrification, and a fifth treatment mixture is obtained.

[0041] The fifth treatment mixture enters the anoxic zone 8, and the sludge drawn from the secondary sedimentation tank 10 by the second sludge return pump 14 enters the anoxic zone 8 through the second sludge return pipe 13 at the same time, is stirred and mixed by the electric agitator 19 extending into the anoxic zone 8, and is subjected to long anoxia to convert nitrate nitrogen into nitrogen, thereby denitrifying and obtaining a sixth treatment mixture.

[0042] The total hydraulic retention time of the aerobic-anoxic variable zone 7 and the anoxic zone 8 is 6.5-8.2 h, and the sludge return ratio is 70%-120%, and the concentration of the returned sludge is 4000-5500 mg / L.

[0043] The sludge remaining in the secondary sedimentation tank 10 is discharged from the sludge discharge pipe 31.

[0044] In step 4, the sixth treatment mixture enters the anoxic-aerobic variable zone 9, the anoxic-aerobic variable zone 9 is operated in an aerobic mode, and the dissolved oxygen is set to 1-1.5 mg / L; the main role of this anoxic-aerobic variable zone 9 is to further strengthen nitrification and deeply oxidize organic matter, and obtain a final treatment mixture.

[0045] The final treatment mixture enters the secondary sedimentation tank 10 for sedimentation, and the obtained upper clear water has an effluent ammonia nitrogen of <1.5 mg / L and a COD of <20 mg / L, thereby achieving discharge standards.

[0046] In step 5, the water tank 1, the aerobic zone 6, the anoxic zone 8, and the anoxic-aerobic variable zone 9 are all provided with water quality online monitoring equipment 24, which can feed back the COD, ammonia nitrogen, total nitrogen, and total phosphorus indexes to the computer 30 in real time. The aerobic zone 6 and the anoxic-aerobic variable zone 9 are both provided with online DO monitoring probes 20 and are connected to a handheld dissolved oxygen meter 21, and real-time signals are fed back to the computer 30. When the DO value is lower than the set lower limit value, the air blower 17 is started, and the aeration pipe 16 is used to blow air to the aeration heads 15 in the anaerobic-aerobic variable zone 5, the aerobic zone 6, the aerobic-anoxic variable zone 7, and the anoxic-aerobic variable zone 9 to increase the DO value. When the DO value is higher than the set upper limit value, the air blower 17 is turned off.

[0047] Example 1 is a stable running state under the stress of industrial wastewater and low temperature, and by adding a hydrolysis acidification section and shortening the hydraulic retention time in the anaerobic section (the hydraulic retention time is 1.5-2.5 h), macromolecular organic matter is converted into small-molecular organic matter under the premise of minimizing carbon source consumption, thereby ensuring the efficient synthesis of internal carbon source PHA in the anaerobic section and ammoniating organic nitrogen; the anaerobic-aerobic variable zone 5 is adjusted to operate in an aerobic mode, and short-cut nitrification sludge embedding bodies 23 are added to the aerobic zone 6, which can improve the ammonia oxidation efficiency of the system and achieve a nitrite accumulation rate of more than 60%; the anoxic section relies on internal carbon sources and stored substances to drive denitrification, and uses nitrite nitrogen as an electron acceptor, so that stable denitrification performance can be maintained under the condition of relatively limited carbon sources without the need for external carbon sources.

[0048] The mode can improve the concentration of functional bacteria by adjusting the proportion of each stage and adding the embedding body 23, can effectively cope with the adverse effects of low temperature ammonia oxidation efficiency reduction, can realize efficient conversion of organic nitrogen and deep removal of total nitrogen, and provides a reliable technical path for low temperature, low carbon-nitrogen ratio and high organic nitrogen ratio wastewater.

[0049] Embodiment 2 When the industrial wastewater is stressed under the condition of high total nitrogen load: Step 1, under the condition that the water quality fluctuates greatly, the total nitrogen is 70-100 mg / L (organic nitrogen / total nitrogen: 10%-15%), the water temperature is <15℃, and the C / N is 3-6; the total nitrogen is higher than that in embodiment 1, and the carbon-nitrogen ratio is lower than that in embodiment 1.

[0050] The same as step 1 of embodiment 1 in step 1 of embodiment 2 is that the organic nitrogen is decomposed and ammoniated in the hydrolysis acidification zone 3, and then enters the anaerobic zone 4, and also enters the sludge at the end of the secondary sedimentation tank 10, which is extracted by the first sludge return pump 12.

[0051] Different from step 1 of embodiment 1 is that the sludge return ratio is 100%-150%, the return sludge concentration is 4000-5500 mg / L, and the mixture is stirred by the electric mixer 19, the denitrifying phosphorus accumulating organisms in the anaerobic zone 4 synthesize the internal carbon source PHA from small molecule volatile fatty acids VFAs, and release phosphate.

[0052] Step 2, different from step 2 of embodiment 1 is that the anaerobic and aerobic variable zone 5 is operated in an anaerobic mode, the anaerobic mode is prolonged, and the internal carbon source synthesis and phosphorus release are strengthened.

[0053] Step 3, different from step 3 of embodiment 1 is that the fourth treatment mixed solution containing a large amount of nitrate nitrogen / nitrite nitrogen enters the aerobic and anoxic variable zone 7, and the aerobic and anoxic variable zone 7 is operated in an aerobic mode.

[0054] The anoxic zone 8 synchronously enters the sludge extracted from the secondary sedimentation tank 10 by the second sludge return pump 14, and different from embodiment 1 is that the sludge return ratio is 100%-150% (higher than embodiment 1), the return sludge concentration is 4000-5500 mg / L, the mixture is stirred by the electric mixer 19, and the nitrate nitrogen is converted into nitrogen gas by long anoxic, so as to carry out denitrification. The residence time in the anoxic zone 8 is 5.5-7.2 h.

[0055] Step 4, same as step 4 of embodiment 1.

[0056] Step 5, same as step 5 of embodiment 1.

[0057] Embodiment 2 is the operation under the conditions of low temperature, high organic nitrogen ratio, and high total nitrogen load of industrial wastewater stress. The organic matter in the influent will be adsorbed and converted into internal carbon source by the sludge in the anaerobic zone 4. Under the condition of high total nitrogen load, the stable short-cut nitrification in the aerobic zone 6 and the effect of anaerobic ammonia oxidation in the anaerobic zone 4 can be achieved by prolonging the hydraulic retention time (2-3.5 h) of the anaerobic section, improving the sludge return ratio, adding the filler in the anaerobic zone 4, and adding the short-cut sludge embedding body 23 in the aerobic zone 6. The total nitrogen removal in the anaerobic zone 4 is achieved. This strategy promotes the internal storage (such as PHA) of limited carbon source by microorganisms such as phosphorus accumulating bacteria and glycan bacteria in the anaerobic environment, reserves the necessary internal carbon source for subsequent anoxic denitrification, effectively alleviates the contradiction of insufficient external carbon source, and provides stable nitrite nitrogen substrate for anaerobic ammonia oxidation bacteria.

[0058] Under the double pressure of low temperature and water quality fluctuation, this operation adjustment helps to stabilize the system performance and achieve efficient removal of total nitrogen without additional carbon source.

[0059] Embodiment 3 Low-temperature wastewater under the conditions of low load, low C / N ratio, and water shock: Step 1, when the total nitrogen is about 30-40 mg / L, the temperature is less than 15℃, and the C / N ratio is about 3-4 (lower than Embodiments 1 and 2, low temperature and low carbon nitrogen ratio), the rest is the same as Step 1 of Embodiment 1.

[0060] Step 2, the same as Step 2 of Embodiment 1.

[0061] Step 3, which is different from Step 3 of Embodiment 1: A small amount of external carbon source needs to be added in the anoxic zone 8 through the carbon source addition pump 29 connected to the external carbon source storage tank 28. The type is composite carbon source, 1 mgN adds 1-3 mgCOD equivalent carbon source, to avoid the decrease of treatment efficiency due to insufficient carbon source and maintain the stability of the system.

[0062] The nitrate concentration feedback by the water quality online multi-parameter monitoring equipment 25 connected to the online monitoring nitrate probe 26 in the anoxic zone 8, when the nitrate concentration NO3 - -N is greater than 10 mg / L and C / N is less than 5, start the external carbon source addition pump 29 and add carbon source; when NO3 - -N is less than 8 mg / L, close the external carbon source addition pump 29.

[0063] Step 4, which is different from Step 4 of Embodiment 1: The anoxic and aerobic variable zone 9 operates in anoxic mode, prolongs the anoxic time, and enhances the activity of denitrifying bacteria. The core function is to achieve denitrification and remove nitrogen elements in wastewater.

[0064] Step 5, unlike step 5 of example 1: According to the effluent ammonia nitrogen concentration of the anoxic and aerobic variable zone 9 fed back by the computer 30, the setting range of DO is adjusted accordingly: When the ammonia nitrogen concentration NH4 + -N<1.5mg / L, DO is 0.5~1mg / L; when 1.5mg / L<NH4 + -N<8mg / L, DO is 1~1.5mg / L; when NH4 + -N>8mg / L, DO is 1.5~2mg / L.

[0065] Example 3 is the operation of water impact low load and low C / N ratio, the system will face the double challenge of absolute shortage of carbon source and decline of reaction driving force. Combined with the data acquisition of online equipment and model calculation, the operation strategy of prolonging the hydraulic retention time of anoxic section (the hydraulic retention time is 6~8h) and supplementing with precise addition of external carbon source can effectively guarantee the thoroughness of denitrification, make up the structural shortage of carbon source, and maintain the microbial activity and system stability to cope with the sudden situation of water quality stability and standard reaching.

[0066] In the above examples, the description of each example has its own emphasis, and the parts not described or recorded in a certain example can be referred to the related description of other examples.

[0067] Figure 1 The structural diagram of the device provided by the application is based on the same inventive concept, and the device provided by the embodiment of the application is also provided for the AOA method for treating high organic nitrogen and low temperature continuous flow based on the short-range nitrifying bacteria embedding body 23, which comprises: a hydrolysis acidification zone 3, an anaerobic zone 4, an anaerobic and aerobic variable zone 5, an aerobic zone 6, an aerobic and anoxic variable zone 7, an anoxic zone 8, an anoxic and aerobic variable zone 9 and a secondary sedimentation tank 10 connected in sequence. The secondary sedimentation tank 10 is connected with the anaerobic zone 4 through a first sludge return pipe 11 and connected with the anoxic zone 8 through a second sludge return pipe 13; a first sludge return pump 12 is arranged on the first sludge return pipe 11, and a second sludge return pump 14 is arranged on the second sludge return pipe 13.

[0068] The device also comprises an external carbon source storage tank 28, a water tank 1, a blower 17 and an electric stirrer 19. The external carbon source storage tank 28 is connected with the anoxic zone 8, and a carbon source adding pump 29 is arranged on the pipeline between the external carbon source storage tank 28 and the anoxic zone 8; the water tank 1 is connected with the hydrolysis acidification zone 3 through a water inlet pump 2. The electric stirrers 19 are arranged in the hydrolysis acidification zone 3, the anaerobic zone 4, the anaerobic and aerobic variable zone 5, the aerobic zone 6, the aerobic and anoxic variable zone 7, the anoxic zone 8 and the anoxic and aerobic variable zone 9.

[0069] The blower 17 is connected with the aeration head 15 in the anaerobic-aerobic variable zone 5, the aerobic zone 6, the aerobic-anoxic variable zone 7, the anoxic zone 8 and the anoxic-aerobic variable zone 9 through the aeration pipe 16.

[0070] The suspended biological filler 22 is placed in the anaerobic zone 4, and the embedding body 23 is placed in the aerobic zone 6.

[0071] According to the process flow, the anaerobic zone 4 is divided into a first anaerobic section 41 and a second anaerobic section 42, and the suspended biological filler 22 and the electric agitator 19 are arranged in each anaerobic section.

[0072] According to the process flow, the aerobic zone 6 is divided into a first aerobic section 61 and a second aerobic section 62, and the embedding body 23, the electric agitator 19 and the aeration head 15 are arranged in each aerobic section.

[0073] According to the process flow, the anoxic zone 8 is divided into a first anoxic section 81, a second anoxic section 82, a third anoxic section 83, a fourth anoxic section 84, a fifth anoxic section 85 and a sixth anoxic section 86, and the electric agitator 19 and the aeration head 15 are arranged in each anoxic section.

[0074] The device further comprises a computer 30, a PLC controller 18, a water quality online multi-parameter monitoring device 25, an online monitoring nitrate probe 26, an online DO monitoring probe 20, an online ammonia nitrogen monitoring probe 27 and a handheld dissolved oxygen meter 21 connected through an electrical circuit.

[0075] The online monitoring nitrate probe 26 arranged in the anoxic zone 8 is connected with the water quality online multi-parameter monitoring device 25, and the real-time data fed back by the computer 30 is used to start the carbon source dosing pump 29 to dose the carbon source.

[0076] The online DO monitoring probe 20 arranged in the aerobic zone 6 and the anoxic-aerobic variable zone 9 is connected with the handheld dissolved oxygen meter 21, and the online ammonia nitrogen monitoring probe 27 is connected with the water quality online multi-parameter monitoring device 25, and the real-time signal is fed back to the computer 30.

[0077] The water tank 1 is provided with a water quality online monitoring device 24, and the computer 30 is connected with the PLC controller 18 to adjust the air volume of the blower 17.

[0078] The above only describes the preferred embodiments of the present application and is not used to limit the present application, and any modification, equivalent replacement and improvement made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high organic nitrogen low temperature continuous flow AOA treatment process characterized by, The method comprises: The final treatment mixed liquor formed after the low-temperature wastewater sequentially passes through the hydrolysis acidification zone (3), the anaerobic zone (4), the anaerobic and aerobic variable zone (5), the aerobic zone (6), the aerobic and anoxic variable zone (7), the anoxic zone (8), and the anoxic and aerobic variable zone (9) is introduced into the secondary sedimentation tank (10) for sedimentation and separation, the clarified water on the upper layer reaches the discharge standard and is discharged, and the sludge deposited at the bottom of the secondary sedimentation tank (10) is recycled; The first treatment mixed liquor obtained after the decomposition and ammonification of organic nitrogen in the low-temperature wastewater in the hydrolysis acidification zone (3) is introduced into the anaerobic zone (4), the sludge extracted from the secondary sedimentation tank (10) is synchronously introduced into the anaerobic zone (4) through the first sludge return pipe (11), the first treatment mixed liquor, the synchronously introduced sludge, and the suspended biological filler (22) added into the anaerobic zone (4) are mixed, the anaerobic ammonia oxidation bacteria enriched under anoxic conditions convert ammonia nitrogen into nitrogen gas to achieve denitrification, the denitrifying phosphorus accumulating organisms enriched convert into small-molecule volatile fatty acids (VFAs) and synthetic internal carbon source (PHA) to release phosphate, achieving denitrification and phosphorus removal, and the second treatment mixed liquor is obtained; The third treatment mixed liquor obtained through the anaerobic and aerobic variable zone (5) is introduced into the aerobic zone (6) to absorb phosphorus, and ammonia nitrogen is oxidized into nitrite nitrogen and nitrate nitrogen; under a low-dissolved oxygen condition, the short-cut nitrification and denitrification bacteria are enriched in the embedded body (23) in the aerobic zone (6) to strengthen denitrification and phosphorus removal under a low-temperature condition, and the fourth treatment mixed liquor is obtained; The fourth treatment mixed liquor containing a large amount of nitrate nitrogen / nitrite nitrogen is introduced into the aerobic and anoxic variable zone (7), part of the nitrogen is removed through simultaneous nitrification and denitrification under an anoxic mode to obtain the fifth treatment mixed liquor, the fifth treatment mixed liquor is mixed with the sludge synchronously extracted from the secondary sedimentation tank (10) and introduced into the sludge through the second sludge return pipe (13) through the long anoxic mode to convert the nitrate nitrogen into nitrogen gas to achieve denitrification, and the sixth treatment mixed liquor is obtained; The sixth treatment mixed liquor is introduced into the anoxic and aerobic variable zone (9) to form the final treatment mixed liquor reaching the discharge standard.

2. The high organic nitrogen low temperature continuous flow AOA treatment process of claim 1 wherein, When the low-temperature wastewater is wastewater under industrial wastewater stress: The total nitrogen in the low-temperature wastewater is 50-70 mg / L, the percentage of organic nitrogen / total nitrogen is 10%-20%, the C / N ratio is 4-7, and the water temperature is less than 15℃.

3. The high organic nitrogen low temperature continuous flow AOA treatment process of claim 2 wherein, The sludge return ratio of the sludge synchronously introduced into the anaerobic zone (4) is 70%-120%, and the return sludge concentration is 4000-5500 mg / L; the filling ratio of the suspended biological filler (22) added into the anaerobic zone (4) is 20%-30%.

4. The high organic nitrogen low temperature continuous flow AOA treatment process of claim 2 wherein, The anaerobic and aerobic variable zone (5) is operated in an aerobic mode, and the dissolved oxygen is 1-4 mg / L to strengthen complete nitrification.

5. The high organic nitrogen low temperature continuous flow AOA treatment process of claim 2 wherein, The embedded body (23) comprises polyvinyl alcohol (PVA) and sodium alginate (SA), is fixed in the aerobic zone (6) through silk screen after mixing and solidification, and the filling ratio is 30%-40%.

6. The high organic nitrogen low temperature continuous flow AOA treatment process of claim 2 wherein, The sludge synchronously introduced into the anoxic zone (8) has a sludge return ratio of 70%-120% and a return sludge concentration of 4000-5500 mg / L.

7. The high organic nitrogen low temperature continuous flow AOA treatment process of claim 2 wherein, The anoxic and aerobic variable zone (9) is operated in aerobic mode, with dissolved oxygen set at 1-1.5 mg / L, to strengthen nitrification and deep oxidation of organic matter, so as to reach the effluent discharge standard: ammonia nitrogen <1.5 mg / L, and COD <20 mg / L.

8. The high organic nitrogen low temperature continuous flow AOA treatment process of claim 1 wherein, When the low-temperature wastewater to be treated is industrial wastewater under high total nitrogen load stress: The total nitrogen is 70-100 mg / L, the percentage of organic nitrogen to total nitrogen is 10-15%, the water temperature is <15℃, and the C / N ratio is 3-6; The sludge return ratio synchronously entering the anaerobic zone (4) is 100-150%, and the return sludge concentration is 4000-5500 mg / L; The anaerobic and aerobic variable zone (5) is operated in anaerobic mode to prolong the anaerobic zone (4) to strengthen internal carbon source synthesis and phosphorus release; The sludge return ratio synchronously entering the anoxic zone (8) is 100-150%, and the return sludge concentration is 4000-5500 mg / L.

9. The high organic nitrogen low temperature continuous flow AOA treatment process of claim 1 wherein, When the low-temperature wastewater is under water quantity impact low load and low C / N ratio conditions: The total nitrogen is 30-40 mg / L, the water temperature is <15℃, and the C / N ratio is 3-4; In the anoxic zone (8), a small amount of external carbon source is added by an external carbon source tank (28) connected by a carbon source adding pump (29), 1 mg N is added with 1-3 mg COD equivalent carbon source, and the carbon source is maintained stable; when the nitrate concentration NO3 - The carbon source adding pump (29) is started when NO3 - The carbon source adding pump (29) is closed when NO3 The anoxic and aerobic variable zone (9) is operated in anoxic mode to prolong the anoxic time, enhance the activity of denitrifying bacteria, and remove nitrogen and phosphorus; According to the effluent ammonia nitrogen concentration of the anoxic and aerobic variable zone (9), the setting range of DO is adjusted: when the ammonia nitrogen concentration NH4 + -N<1.5mg / L, DO is 0.5~1mg / L; when 1.5mg / L<NH4 + -N<8mg / L, DO is 1~1.5mg / L; when NH4 + -N>8mg / L, DO is 1.5~2mg / L.

10. An apparatus for the high organic nitrogen low temperature continuous flow AOA treatment method as claimed in any one of claims 1 to 9, characterized by, Comprise: The hydrolysis acidification zone (3), the anaerobic zone (4), the anaerobic and aerobic variable zone (5), the aerobic zone (6), the aerobic and anoxic variable zone (7), the anoxic zone (8), the anoxic and aerobic variable zone (9), and the secondary sedimentation tank (10) are sequentially connected; the secondary sedimentation tank (10) is connected with the anaerobic zone (4) through the first sludge return pipe (11) and connected with the anoxic zone (8) through the second sludge return pipe (13); Further comprising an external carbon source storage tank (28) connected with the anoxic zone (8).

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