Anoxic mud membrane MBBR enhanced secondary biological treatment effluent extreme denitrification device and method

Abstract

The device and method for the extreme denitrification of the effluent from the anoxic sludge membrane MBBR enhanced secondary biological treatment belong to the technical field of biological treatment of municipal sewage. The main process consists of four parts: a municipal sewage raw water tank, a low sludge age A / O reactor, an anoxic sludge membrane-moving bed biofilm reactor (MBBR), and a secondary sedimentation tank. By adjusting the operating parameters and adding blank fillers to the low sludge age A / O continuous flow reactor, anaerobic ammonia oxidizing bacteria are quickly self-enriched to achieve dual short-range coupled anaerobic ammonia oxidation autotrophic denitrification. The effluent from the A / O secondary biological treatment and municipal sewage enter the anoxic sludge membrane MBBR deep denitrification device in a certain proportion. The residual sludge from the low sludge age A / O reactor is used as the carbon source. Through in-situ sludge hydrolysis, acidification, denitrification and anaerobic ammonia oxidation coupled, the extreme denitrification of municipal sewage based on multi-pathway anaerobic ammonia oxidation is finally achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of sewage biological treatment, and in particular relates to an extreme denitrification device and method for anoxic mud membrane MBBR enhanced secondary biological treatment of effluent. Background Art

[0002] To prevent eutrophication, nitrogen must be removed from wastewater. Biological denitrification through nitrification / denitrification is currently the most commonly used method in wastewater treatment plants (WWTPs). However, this biological process is not sustainable and requires significant energy and carbon sources to maintain the system's denitrification performance. Recently, anaerobic ammonium-oxidizing (Anammox) bacteria have been discovered in denitrifying filters. Anammox bacteria can oxidize ammonia to nitrogen gas under anoxic conditions using nitrite as an electron acceptor. The application of anaerobic ammonium oxidation technology in wastewater treatment reduces the energy consumption of wastewater treatment plants because approximately 45% of ammonia nitrogen can be anaerobically oxidized in the absence of oxygen. As a mature wastewater denitrification technology, anaerobic ammonium oxidation has been widely used in the treatment of high-ammonia nitrogen wastewater, commonly known as the sidestream anaerobic ammonium oxidation process. Recently, the application of anammox to mainstream treatment (commonly known as the mainstream anammox process) has been proposed, which has the potential to achieve energy-neutral or even energy-sustaining wastewater treatment. However, the application of anaerobic ammonium oxidation in low-ammonia nitrogen wastewater systems faces some challenges, one of the main bottlenecks being how to enable anaerobic ammonium oxidation bacteria to stably obtain their important nitrite substrate.

[0003] Recently, the multi-path coupling process of anaerobic ammonium oxidation based on short-cut nitrification (PN)-short-cut denitrification (PD) has shown significant advantages for stable autotrophic nitrogen removal. The combination of PN / A and PDN / A may be a very promising process to improve denitrification performance because they have inherent complementary advantages. Nitrate accumulated from PN / A can be further removed by PD / A under limited ammonia nitrogen and organic matter. Studies have shown that the combination of PN / A and PD / A can further improve the denitrification efficiency. However, most studies are based on the inoculation of mature anaerobic ammonium oxidizing bacteria. How to achieve rapid self-enrichment of anaerobic ammonium oxidizing bacteria under multi-pathway nitrite supply conditions in actual mainstream low-ammonia urban sewage is more realistic for large-scale application.

[0004] The biological denitrification process produces a large amount of excess activated sludge (WAS). The treatment and disposal costs of WAS are very high, accounting for about 60% of the total cost of the sewage treatment plant. If the organic matter contained in WAS (such as proteins and polysaccharides) can be effectively released, it can not only reduce the amount of sludge, but also serve as an internal carbon source for biological denitrification, thereby saving operating costs and achieving sludge reduction. Currently, there is very limited research on using excess sludge as a carbon source to achieve anaerobic ammonium oxidation autotrophic denitrification based on nitrite supply from the short-range denitrification pathway. Summary of the Invention

[0005] To address the difficulties of achieving deep denitrification in low C / N municipal sewage and the high cost of sludge treatment, this paper proposes an anoxic sludge membrane MBBR (MBBR) enhanced secondary biological treatment effluent extreme denitrification device and method. The purpose is to achieve rapid self-enrichment of anaerobic ammonia-oxidizing bacteria through multi-pathway nitrite supply (short-cut nitrification and short-cut denitrification) to enhance autotrophic denitrification, and to combine in-situ sludge hydrolysis and acidification to achieve deep denitrification while simultaneously reducing and stabilizing sludge.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is to first add a certain proportion of blank filler into the low sludge age A / O reactor to provide a carrier for the self-enrichment of anaerobic ammonia oxidation, and by controlling the hydraulic retention time of the anaerobic compartment and the dissolved oxygen in the aerobic compartment combined with a low sludge age, achieve rapid self-enrichment and enhanced autotrophic denitrification of anaerobic ammonia oxidation under dual short-term nitrite supply conditions. The residual sludge generated is directly added as a carbon source to the in-situ sludge hydrolysis, acidification, denitrification and anoxic sludge film MBBR reactor, achieving sludge reduction and stabilization while performing deep denitrification through the short-term denitrification and anaerobic ammonia oxidation pathway.

[0007] The present invention provides an anoxic mud film MBBR enhanced secondary biological treatment effluent extreme denitrification device and method, the device mainly comprises a municipal sewage raw water tank (1), a low sludge age A / O reactor (2), a secondary sedimentation tank (3), an anoxic mud film MBBR (4), and a rear secondary sedimentation tank (5); the low sludge age A / O reactor is divided into four compartments by a perforated partition plate, which are anaerobic compartment (2.1), aerobic first compartment (2.2), aerobic second compartment (2.3), aerobic The third cell (2.4) is filled with blank filler (2.6) with a volume filling ratio of 10-20%; the anaerobic cell is provided with a stirrer (2.5); the urban sewage raw water tank (1) pumps urban sewage into the anaerobic cell (2.1) in the low sludge age A / O reactor (2) through the water inlet pump (1.1); the aeration pump (2.10) is connected to the aeration disk (2.8) through the rotor flow meter (2.9); the detection device DO sensor (2.7) is connected to the WTW host (2.12) The WTW host (2.12) is connected to the computer (2.13); the bottom of the secondary sedimentation tank (3) is connected to the anaerobic grid (2.1) through the sludge return control valve (3.2) and the sludge return pump (2.11), and the residual sludge is discharged through the control valve (3.3); the effluent of the low sludge age A / O reactor (2) enters the anoxic mud film MBBR extreme denitrification device (4) through the rear water inlet pump (4.1); the urban sewage is discharged through the water inlet pump (4.5) and the residual sludge generated by the low sludge age A / O reactor. The sludge passes through the sludge discharge valve (3.3) and the sludge pump (4.6) into the anoxic mud film MBBR (4); after deep denitrification treatment, the sludge is separated in the secondary sedimentation tank (5) and the final water is discharged; the sludge at the bottom of the sedimentation tank is connected to the front end of the MBBR reactor (4) through the sludge return control valve (5.2) and the sludge return pump (4.4); the anoxic mud film MBBR (4) is equipped with an anaerobic ammonium oxidation filler (4.3) with a volume filling ratio of 20-25% and an agitator (4.2). The secondary sedimentation tank is equipped with a sludge scraper (3.1) and (5.1).

[0008] The specific running and operation steps are as follows:

[0009] 1) Low sludge age A / O reactor self-enrichment anaerobic ammonium oxidation enhanced autotrophic nitrogen removal

[0010] The wastewater treatment plant's excess sludge is inoculated into a continuous flow low sludge age A / O reactor, the sludge concentration (MLSS) is controlled at 2500-3500 mg / L, and a blank filler with a volume filling ratio of 10-20% is added to the reactor. The influent is municipal sewage, the sludge return volume ratio is 100%-150%, and the sludge age is 4-6.5 days. The hydraulic retention time (HRT) of the anaerobic cell is 40-60 minutes, and the HRT of the aerobic cell is 120-140 minutes. The dissolved oxygen concentration in the aerobic cell is controlled in a decreasing aeration mode, with the first aerobic cell controlled at 0.8-2 mg / L, the second aerobic cell controlled at 0.5-1.5 mg / L, and the third aerobic cell controlled at below 0.5 mg / L.

[0011] When the nitrate nitrogen concentration in the effluent of the anaerobic compartment is less than 1 mg / L, reduce the hydraulic retention time of the anaerobic compartment to 40-45 min and increase the sludge return volume ratio (R) to 1.4-1.5. When the ammonia nitrogen concentration in the effluent of the aerobic compartment is less than 1 mg / L, the dissolved oxygen concentrations in the first and second aerobic compartments are reduced to 0.8-1 mg / L and 0.5-1 mg / L, respectively. When the ammonia nitrogen concentration in the effluent of the aerobic compartment is greater than 5 mg / L, the dissolved oxygen concentrations in the first and second aerobic compartments are increased to 1.5-2 mg / L and 1-1.5 mg / L, respectively. When the theoretical initial ammonia nitrogen concentration of the anaerobic compartment minus the ammonia nitrogen concentration in the effluent is greater than 2 mg / L and the total inorganic nitrogen removal contribution rate of the aerobic compartment is greater than 40%, the total inorganic nitrogen (TIN) removal rate of the reactor (TIN) is greater than 40%. 进 -TIN 出 ) / TIN 进 ) minus the theoretical removal rate (R / (R+1)*100%) was greater than 20% and maintained stably for more than 30 days, indicating that anaerobic ammonium-oxidizing bacteria were successfully enriched in the biofilm in the low sludge age A / O reactor and autotrophic nitrogen removal was enhanced;

[0012] 2) Startup and stable operation of anoxic mud membrane MBBR to achieve extreme denitrification of urban sewage

[0013] The excess sludge generated daily by the low-sludge-age A / O reactor is pumped directly into the downstream reactor for at least 10 consecutive days. During this process, the reactor undergoes only anaerobic agitation without sewage treatment to rapidly enrich hydrolytic and acidifying bacteria. When the sludge concentration reaches 3500 mg / L or above, mature anaerobic ammonium oxidation (ANAMMOX) filler is inoculated at a volumetric filling ratio of 20%-25%. The effluent from the successfully activated low-sludge-age A / O reactor and municipal sewage are then fed into the anoxic sludge membrane MBBR at a ratio of 10:1-5:1. The sludge return volume ratio of the anoxic sludge membrane MBBR reactor is 100%, the hydraulic retention time is 8-10 hours, and the reactor does not actively discharge sludge.

[0014] When the effluent ammonia nitrogen concentration exceeded 3 mg / L, the influent ratio of the front-end effluent to municipal sewage was adjusted to 10:1 and the hydraulic retention time was extended to 9-10 hours. When the effluent ammonia nitrogen concentration was less than 1 mg / L, the total inorganic nitrogen was less than 2 mg / L, and the total nitrogen removal rate exceeded 98% and remained stable for more than 30 days, indicating that the in-situ sludge hydrolysis, acidification, and denitrification coupled with anaerobic ammonium oxidation anoxic MBBR system was successfully started and achieved long-term stable operation.

[0015] The specific characteristics of the extreme denitrification device for the anoxic mud membrane MBBR enhanced secondary biological treatment effluent are as follows:

[0016] 1) Sewage enters the anaerobic compartment of the low sludge age A / O reactor, where the floc sludge uses the organic matter in the influent to perform short-cut denitrification, providing the substrate nitrite for the anaerobic ammonium oxidizing bacteria in the biofilm to achieve anaerobic oxidation of ammonia nitrogen. It then enters the aerobic zone, where the low floc sludge age and the dissolved oxygen in the aerobic compartment are controlled to elute the nitrite oxidizing bacteria and achieve short-cut nitrification. The anaerobic ammonium oxidizing bacteria in the biofilm use the nitrite produced by short-cut nitrification and the ammonia nitrogen in the sewage to perform anaerobic ammonium oxidation autotrophic denitrification.

[0017] 2) The effluent from the low sludge age A / O reactor and the raw water enter the anoxic sludge membrane MBBR in a certain ratio. The excess sludge produced by the front-end low sludge age reactor is used as a carbon source. Through in-situ sludge hydrolysis, acidification and denitrification coupled with anaerobic ammonium oxidation, the low C / N urban sewage multi-pathway anaerobic ammonium oxidation extreme denitrification is achieved, while the excess sludge is reduced and stabilized.

[0018] The present invention relates to an anoxic mud membrane MBBR enhanced secondary biological treatment effluent extreme denitrification device and application method, which has the following advantages over the prior art:

[0019] 1) Through multi-pathway anaerobic ammonia oxidation autotrophic denitrification technology, the dependence on external carbon source addition is eliminated to achieve extreme denitrification of low C / N urban sewage.

[0020] 2) The low sludge age A / O reactor has a shorter aerobic hydraulic retention time and does not require internal circulation of nitrification liquid, which greatly reduces the energy consumption of aeration and internal circulation.

[0021] 3) The system achieves “self-production and self-consumption” of excess sludge through in-situ sludge hydrolysis and acidification technology. The entire system does not generate additional solid waste, greatly reducing the cost of excess sludge treatment and laying a solid foundation for the transformation of sewage treatment plants from energy-demanding to energy-self-sufficient. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the structure of the extreme denitrification device for the anoxic mud membrane MBBR enhanced secondary biological treatment of effluent;

[0023] Figure 1 1- Municipal sewage raw water tank; 2- Low sludge age A / O reactor; 3- Secondary sedimentation tank; 4- Anoxic mud film MBBR; 5- Secondary sedimentation tank; 1.1- Inlet pump; 2.1- Anaerobic cell; 2.2- Aerobic first cell; 2.3- Aerobic second cell; 2.4- Aerobic third cell; 2.5- Agitator; 2.6- Suspended filler; 2.7- Dissolved oxygen sensor; 2.8- Aeration plate; 2.9- Rotor flowmeter; 2.10- Aeration pump; 2 .11-Sludge return pump; 2.12-WTW main unit; 2.13-Computer; 3.1-Secondary sedimentation tank scraper; 3.2-Return sludge control valve; 3.3-Sludge discharge control valve; 4.1-Water inlet pump; 4.2-Agitator; 4.3-Anaerobic ammonium oxidation filler; 4.4-Sludge return pump; 4.5-Municipal sewage inlet pump; 4.6-Sludge pump; 5.1-Secondary sedimentation tank scraper; 5.2-Sludge return control valve; 5.3-Sludge discharge valve. DETAILED DESCRIPTION

[0024] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments. The feature of the device for the extreme denitrification of the effluent by the anoxic mud film MBBR for strengthening the secondary biological treatment is that the device required for application includes a municipal sewage raw water tank (1), a low sludge age A / O reactor (2), a secondary sedimentation tank (3), anoxic mud film MBBR (4), and a rear secondary sedimentation tank (5); the low sludge age A / O reactor is divided into four compartments by a perforated partition plate, which are anaerobic compartments (2.1), aerobic first compartments (2.2), aerobic second compartments (2.3) and aerobic second compartments (2.4) along the water inlet direction. The second aerobic cell (2.3) and the third aerobic cell (2.4) are each filled with a blank filler (2.6) with a volume filling ratio of 10-20%; the anaerobic cell is provided with a stirrer (2.5); the urban sewage raw water tank (1) pumps urban sewage into the anaerobic cell (2.1) in the low sludge age A / O reactor (2) through the water inlet pump (1.1); the aeration pump (2.10) is connected to the aeration disk (2.8) through the rotor flowmeter (2.9); the detection device DO sensor (2.7) is connected to the WTW The host (2.12) is connected; the WTW host (2.12) is connected to the computer (2.13); the bottom of the secondary sedimentation tank (3) is connected to the anaerobic grid (2.1) through the sludge return control valve (3.2) and the sludge return pump (2.11), and the remaining sludge is discharged through the control valve (3.3); the effluent of the low sludge age A / O reactor (2) enters the anoxic mud film MBBR (4) extreme denitrification device through the rear water inlet pump (4.1); the urban sewage is discharged through the water inlet pump (4.5) and the low sludge age A / O reactor. The raw excess sludge passes through the sludge discharge valve (3.3) and the sludge pump (4.6) into the anoxic mud film MBBR (4); after deep denitrification treatment, it passes through the secondary sedimentation tank (5) for mud and water separation and completes the final water discharge; the sludge at the bottom of the sedimentation tank is connected to the front end of the MBBR reactor (4) through the sludge return control valve (5.2) and the sludge return pump (4.4); the anoxic mud film MBBR (4) is equipped with an anaerobic ammonium oxidation filler (4.3) with a volume filling ratio of 20-25% and an agitator (4.2). The secondary sedimentation tank is equipped with a sludge scraper (3.1) and (5.1).

[0025] In this specific example, the influent was actual municipal sewage from a city in northern China, with the following water quality indicators: ammonia nitrogen concentration of 36-85 mg / L, nitrite concentration of 0-0.5 mg / L, nitrate concentration of 0-1.8 mg / L, COD concentration of 120-320 mg / L, pH of 6.9-7.5, and COD / TIN ratio of 1.8-4.5. The inoculum sludge was excess sludge from a sewage treatment plant. The effective volumes of the low-sludge-age A / O reactor and the anoxic sludge membrane MBBR were 20 L and 60 L, respectively.

[0026] The detailed steps are as follows:

[0027] 1) Low sludge age A / O reactor self-enrichment anaerobic ammonium oxidation enhanced autotrophic denitrification stage

[0028] A low-sludge-age A / O continuous flow reactor was inoculated with excess sludge from a sewage treatment plant at a concentration of 3180 mg / L. A blank suspended filler with a volumetric fill ratio of approximately 20% was added to each reactor cell. The reactor operated in an anaerobic / aerobic mode, with an anaerobic hydraulic retention time of 45 minutes and an aerobic hydraulic retention time of 135 minutes. The sludge age was 6 days, the sludge return volume ratio was 150%, and the dissolved oxygen concentration in the aerobic zone was controlled at 0.1-2.9 mg / L using a rotor flowmeter. By controlling the anaerobic hydraulic retention time and dissolved oxygen in the aerobic zone, the nitrate nitrogen concentration in the anaerobic cell effluent was maintained at 1-3 mg / L, and the ammonia nitrogen concentration in the aerobic cell effluent was maintained at 0-2 mg / L. Under the condition of a sludge age of 6 days, nitrite accumulation based on short-cut nitrification and short-cut denitrification was achieved in the aerobic compartment and the anaerobic compartment respectively. After 30 days of operation, the ammonia nitrogen removal in the anaerobic compartment could reach 2.5-5 mg / L, and the aerobic compartment showed obvious total inorganic nitrogen loss, accounting for more than 50% of the total inorganic nitrogen removal efficiency. The total inorganic nitrogen removal rate of the low sludge age A / O continuous flow reactor increased from 48% to 85%, far higher than the theoretical denitrification rate of 60%. Anaerobic ammonia oxidation was rapidly enriched in the biofilm and autotrophic denitrification was enhanced.

[0029] 2) Start-up and stable operation of anoxic mud membrane MBBR

[0030] The excess sludge generated daily by the low-sludge-age A / O reactor is directly added as inoculum sludge to the anoxic sludge membrane MBBR. After the sludge concentration reaches 3000 mg / L, mature anaerobic ammonium oxidation filler is added to the anoxic sludge membrane MBBR at a volume filling ratio of 25%. The hydraulic retention time is 9 hours, the sludge return volume ratio is 100%, and the reactor does not actively discharge sludge. The effluent from the low-sludge-age A / O reactor and municipal sewage are combined in a ratio of 10:1 to enter the downstream in-situ sludge hydrolysis, acidification, denitrification, anaerobic ammonium oxidation, and anoxic sludge membrane MBBR deep denitrification device.

[0031] Long-term test results show that the system effluent COD concentration is 20-38 mg / L, the total inorganic nitrogen concentration is less than 2 mg / L, the ammonia nitrogen concentration is less than 1 mg / L, and the total inorganic nitrogen removal rate is greater than 98%, achieving low C / N urban sewage extreme denitrification.

Claims

1. Anoxic mud film MBBR enhanced secondary biological treatment of effluent extreme denitrification method, the method comprises a municipal sewage raw water tank (1), a low sludge age A / O reactor (2), a secondary sedimentation tank (3), anoxic mud film MBBR (4), a rear secondary sedimentation tank (5); the low sludge age A / O reactor is a kind of anaerobic sludge film MBBR, which ... The reactor is divided into four compartments by a perforated partition, which are anaerobic compartment (2.1), aerobic first compartment (2.2), aerobic second compartment (2.3), and aerobic third compartment (2.4) in the order of water inlet, and blank filler (2.6) with a volume filling ratio of 10-20% is added to each compartment; the anaerobic compartment is provided with a stirrer A (2.5); the urban sewage raw water tank (1) pumps urban sewage into the anaerobic compartment (2.1) in the low sludge age A / O reactor (2) through the water inlet pump A (1.1); the aeration pump (2.10) is connected to the aeration disk (2.8) through the rotor flowmeter (2.9); the detection device DO sensor (2.7) is connected to the WTW host (2.12); the WTW host (2.12) is connected to the computer (2.13); the bottom of the secondary sedimentation tank (3) is connected to the anaerobic The cells (2.1) are connected, and the excess sludge is discharged through the sludge discharge valve (3.3); the effluent of the low sludge age A / O reactor (2) enters the anoxic mud film MBBR (4) through the rear water inlet pump (4.1); the urban sewage passes through the water inlet pump B (4.5) and the excess sludge generated by the low sludge age A / O reactor through the sludge discharge valve (3.3) and the sludge pump (4.6) and enters the anoxic mud film MBBR (4) together; after deep denitrification treatment, the final effluent is completed after mud and water separation in the rear secondary sedimentation tank (5); the sludge at the bottom of the rear secondary sedimentation tank is connected to the front end of the anoxic mud film MBBR (4) through the sludge return control valve B (5.2) and the sludge return pump B (4.4); the anoxic mud film MBBR (4) is provided with an anaerobic ammonia oxidation filler (4.3) with a volume filling ratio of 20-25% and a stirrer B (4.2); both secondary sedimentation tanks are provided with a scraper; it is characterized in that Follow these steps:

1. Low sludge age A / O reactor self-enrichs anaerobic ammonium oxidizing bacteria to enhance autotrophic denitrification The wastewater treatment plant excess sludge is inoculated into a continuous flow low sludge age A / O reactor, the sludge concentration (MLSS) is controlled at 2500-3500 mg / L, and a blank filler with a volume filling ratio of 10-20% is added to the A / O reactor. The influent is municipal sewage, the sludge return volume ratio is 100%-150%, and the sludge age is 4-6.5 days. The hydraulic retention time (HRT) of the anaerobic cell is 40-60 minutes, and the HRT of the aerobic cell is 120-140 minutes. The dissolved oxygen concentration in the aerobic cell is controlled in a decreasing aeration mode, with the dissolved oxygen concentration in the first aerobic cell being controlled at 0.8-2 mg / L, the second aerobic cell being controlled at 0.5-1.5 mg / L, and the third aerobic cell being controlled at less than 0.5 mg / L. When the nitrate nitrogen concentration in the effluent of the anaerobic compartment is less than 1 mg / L, the hydraulic retention time of the anaerobic compartment is reduced to 40-45 minutes and the sludge return volume ratio R is increased to 1.4-1.5; when the ammonia nitrogen concentration in the effluent of the aerobic compartment is less than 1 mg / L, the dissolved oxygen concentrations in the first aerobic compartment and the second aerobic compartment are reduced to 0.8-1 mg / L and 0.5-1 mg / L, respectively; when the ammonia nitrogen concentration in the effluent of the aerobic compartment is greater than 5 mg / L, the dissolved oxygen concentrations in the first aerobic compartment and the second aerobic compartment are increased to 1.5-2 mg / L and 1-1.5 mg / L, respectively; when the theoretical initial ammonia nitrogen concentration of the anaerobic compartment minus the ammonia nitrogen concentration in the effluent is greater than 2 mg / L and the total inorganic nitrogen removal contribution rate of the aerobic compartment is greater than 40%, the total inorganic nitrogen removal rate (TIN) of the A / O reactor is greater than 40%. 进 -TIN 出 ) / TIN 进 )*100% minus the theoretical removal rate R / (R+1)*100% is greater than 20% and is maintained stably for more than 30 days, indicating that anaerobic ammonium-oxidizing bacteria are successfully enriched in the biofilm in the low sludge age A / O reactor and autotrophic nitrogen removal is enhanced; 2. Startup and stable operation of anoxic mud membrane MBBR to achieve extreme denitrification of municipal sewage The excess sludge generated daily by the low sludge age A / O reactor is directly pumped into the anoxic sludge membrane MBBR and this operation is continued for more than 10 days. During this process, the anoxic sludge membrane MBBR only performs anaerobic stirring without sewage treatment to rapidly enrich hydrolytic acidifying bacteria. When the sludge concentration reaches above 3500 mg / L, mature anaerobic ammonium oxidation filler is inoculated with a volume filling ratio of 20%-25%. The effluent from the successfully started low sludge age A / O reactor and municipal sewage are fed into the anoxic sludge membrane MBBR at a ratio of 10:1-5:

1. The sludge return volume ratio of the anoxic mud film MBBR is 100%, the hydraulic retention time is 8-10h, and the anoxic mud film MBBR does not actively discharge sludge.

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