Push-flow type built-in sedimentation tank sulfur autotrophic short-cut denitrification and anammox nitrogen removal device

Abstract

A plug-flow type built-in sedimentation tank sulfur autotrophic short-cut denitrification anaerobic ammonia oxidation denitrification device includes a pre-biofilm anoxic tank, a biofilm aerobic tank, and a post-biofilm anoxic tank connected in sequence. Each tank is filled with biofilm-containing packing material and / or filter media, accounting for 20-80% of the volume. Built-in sedimentation tanks are respectively installed in the pre-biofilm anoxic tank and the post-biofilm anoxic tank. A sludge return system and a effluent return system connect the post-biofilm anoxic tank and the pre-biofilm anoxic tank. This invention adopts a built-in sedimentation tank and a dual sludge and effluent return method, effectively avoiding the loss of functional bacteria in sulfur autotrophic denitrification and anaerobic ammonia oxidation, as well as the waste of sulfur filter media. It achieves sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation in a plug-flow multifunctional zone, effectively solving the problems of insufficient carbon source in urban wastewater and low carbon source utilization rate in existing processes, which prevent deep denitrification. The COD removal rate reaches over 80%, and the total nitrogen removal rate is increased to over 90%.

Description

Technical Field

[0001] This invention relates to the field of biological wastewater treatment, and in particular to a plug-flow type built-in sedimentation tank sulfur autotrophic short-cut denitrification anaerobic ammonia oxidation denitrification device and its sulfur autotrophic short-cut denitrification anaerobic ammonia oxidation denitrification method. Background Technology

[0002] Urban sewage is a major source of water pollution. When urban sewage containing large amounts of nitrogen and phosphorus pollutants is discharged into water bodies, it leads to eutrophication, causing the water to become black and smelly. This not only affects aesthetics and human health but also exacerbates water scarcity. The removal of total nitrogen from urban sewage is particularly important, and current treatment mainly employs the traditional nitrification-denitrification biological denitrification process. Dual-recirculation sludge AOA is a novel activated sludge technology that saves energy and chemical consumption. This process includes a sequentially connected anaerobic tank, aerobic tank, and an anoxic tank. Sludge is returned in two paths: one path returns to the front end of the anaerobic tank, and the other path returns to the front end of the anoxic tank. The second return sludge to the anoxic tank provides an internal carbon source for denitrification in the anoxic tank and also increases the number of denitrifying bacteria in the anoxic tank. Invention CN113387442A discloses a fully automated control system and method based on a sludge dual-recirculation AOA process, including an anaerobic tank, an aerobic tank, an anoxic tank, a sedimentation tank, a monitoring system, an aeration system, a sludge discharge system, and a control system. The anaerobic tank, aerobic tank, anoxic tank, and sedimentation tank are connected sequentially. The sludge return port of the sedimentation tank is connected to the anaerobic tank and the anoxic tank through a first sludge return pipe and a second sludge return pipe, respectively. This invention adopts a sludge dual-recirculation structure, in which sludge in the sedimentation tank is returned to the anoxic tank and the anaerobic tank respectively to provide nutrients and a reaction environment for microorganisms. Invention CN107032488B discloses a method for achieving short-cut nitrification of urban wastewater through a sludge dual-recirculation AOA process. This device mainly includes a raw wastewater tank, a sludge dual-recirculation AOA reactor composed of an anaerobic section / aerobic section / anoxic section, and a sedimentation tank. In the anaerobic stage, COD from domestic sewage is used to synthesize internal carbon sources PHAs, while simultaneously releasing phosphorus anaerobically. The mixed liquor then enters the aerobic stage for short-cut nitrification, and finally the anoxic stage for internal carbon source denitrification. However, sludge double-recirculation AOA is mainly limited to the activated sludge process and relies primarily on heterotrophic denitrification for nitrogen removal. It cannot simultaneously achieve deep nitrogen removal and carbon reduction, and it suffers from high residual sludge production, long sludge aging and poor settling properties, requiring larger sedimentation tanks and incurring sludge disposal costs.

[0003] The combination of short-cut denitrification coupled with anaerobic ammonium oxidation (ANAO) and a high-efficiency composite biofilm process can effectively solve the above problems. However, due to the generally low carbon-to-nitrogen ratio of urban wastewater in my country and the lack of carbon sources in raw water, there are almost no biochemically usable organic carbon sources at the end of the biological treatment process for urban wastewater. Even with the aforementioned biofilm process, deep denitrification of urban wastewater cannot be achieved. Furthermore, due to fluctuations in raw water quality, quantity, and temperature, the promotion of this technology still faces challenges such as difficulty in starting up short-cut denitrification and difficulty in stabilizing its long-term operation, which in turn leads to an unstable source of nitrite required for ANAO. Sulfate autotrophic denitrification technology can further alleviate the problem of insufficient organic carbon sources in raw water, while simultaneously achieving short-cut denitrification and producing nitrite during the process. In addition, at the end of the biological treatment zone, sulfur autotrophic short-cut denitrification coupled with ANAO can not only achieve deep denitrification of urban wastewater but also avoid introducing organic matter that would increase the COD of the effluent. The high-efficiency composite biofilm process can not only retain and enrich a large number of nitrifying bacteria, denitrifying bacteria, and anaerobic ammonia oxidizing bacteria, but also avoids the problems of sludge loss, large amount of residual sludge production, and large area occupied by the biological treatment tank.

[0004] Furthermore, current AOA (Automatic Acid-Based Ore) devices and processes with dual sludge recirculation are primarily designed for activated sludge processes and are not suitable for high-efficiency composite biofilm processes (which are pure biofilm processes). For example, the aforementioned literature requires maintaining a certain concentration of activated sludge in the biological treatment tank, especially in the post-anoxic tank, where the sludge age is long and aging. This not only leads to vicious competition between autotrophic and heterotrophic bacteria, making it impossible to screen functional bacteria, but also results in a large amount of excess sludge. Moreover, due to the high sludge concentration and aging, sludge sedimentation is problematic, requiring the configuration of large traditional sedimentation tanks. In addition, due to the loss of activated sludge and the large-scale discharge of excess sludge, the aforementioned patents not only cause the loss and waste of sulfur filter media, but also prevent the enrichment of slowly growing anaerobic ammonia oxidizing bacteria and sulfur autotrophic denitrifying bacteria through activated sludge. The repeated sludge recirculation is also detrimental to achieving independent functional zones such as sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation and aerobic nitrification in plug flow reactors. Most importantly, the dual sludge recirculation of the AOA process described in the aforementioned literature cannot be implemented in pure biofilm processes.

[0005] Therefore, how to combine the advantages of biofilm technology, sulfur autotrophic short-cut denitrification, anaerobic ammonia oxidation, nitrification-heterotrophic denitrification, and dual-recirculation strategy in the form of AOA process and dual-recirculation technology to provide a device that has a small footprint, low residual sludge production, is mainly autotrophic denitrification, can achieve deep denitrification of urban sewage with low carbon-to-nitrogen ratio, low greenhouse gas emissions, avoids the loss of sulfur autotrophic denitrifying bacteria and anaerobic ammonia oxidizing bacteria and the waste of sulfur filter media, and can accurately screen functional bacteria species is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0006] To address the shortcomings of the existing technologies, this invention provides a plug-flow type built-in sedimentation tank sulfur autotrophic short-cut denitrification anammox denitrification device and its method. This invention integrates the advantages of biofilm technology, sulfur autotrophic short-cut denitrification, anammox, nitrification-heterotrophic denitrification, and a dual-recirculation strategy into an improved AOA device and process that features a small footprint, low sludge production, and autotrophic denitrification as its primary function. It achieves deep denitrification of urban wastewater with a low C / N ratio, minimizes greenhouse gas emissions, avoids the loss of sulfur autotrophic denitrifying bacteria and anammox bacteria, and prevents waste of sulfur filter media. It allows for precise screening of functional bacteria and provides a stable nitrite source through sulfur autotrophic denitrification, enhancing the enrichment of anammox bacteria. This constructs a plug-flow type sulfur autotrophic short-cut denitrification device with a multi-functional anammox zone coupled with anammox, thus enhancing the denitrification process.

[0007] In a first aspect, the present invention provides a plug-flow type built-in sedimentation tank sulfur autotrophic short-cut denitrification anaerobic ammonia oxidation denitrification device, comprising a pre-biofilm anoxic tank, a biofilm aerobic tank and a post-biofilm anoxic tank connected in sequence, each tank being filled with packing material and / or filter media with a biofilm accounting for 20-80% of the volume, the pre-biofilm anoxic tank and the post-biofilm anoxic tank being respectively provided with built-in sedimentation tanks, and the post-biofilm anoxic tank and the pre-biofilm anoxic tank being provided with a sludge return system and a tailwater return system.

[0008] Preferably, the pre-biofilm anoxic tank includes a first water distribution pipe connected to a water source, a first built-in sedimentation tank, and a first outlet. The first built-in sedimentation tank is enclosed by a partition A with an inlet screen A, and the first outlet is located above the first built-in sedimentation tank.

[0009] The biofilm aerobic tank includes a second water distribution pipe connected to the first water outlet and a second water outlet.

[0010] The post-biofilm anoxic tank includes a third water distribution pipe connected to the second outlet, a second built-in sedimentation tank, and a third outlet. The second built-in sedimentation tank is enclosed by a partition B with an inlet screen B, and the third outlet is located above the second built-in sedimentation tank.

[0011] The present invention provides a plug-flow type built-in sedimentation tank sulfur autotrophic short-cut denitrification coupled anaerobic ammonia oxidation enhanced nitrogen removal device. Its main body adopts a fully biofilm built-in sedimentation tank AOA process, wherein the volume ratio of the pre-biofilm anoxic tank, the biofilm aerobic tank, and the post-biofilm anoxic tank is preferably 1:1:1. The first built-in sedimentation tank of the pre-biofilm anoxic tank and the second built-in sedimentation tank of the post-biofilm anoxic tank are respectively enclosed by partitions. The first built-in sedimentation tank achieves sludge-water separation; the settled sludge is discharged, and the supernatant is discharged through the first outlet and enters the biofilm aerobic tank, where the biofilm utilizes oxygen to achieve nitrification. Subsequently, it enters the post-biofilm anoxic tank from the second outlet, where the elemental sulfur filter biofilm and the anaerobic ammonia oxidation biofilm achieve sulfur autotrophic short-cut denitrification coupled anaerobic ammonia oxidation. Finally, the effluent passes through the second built-in sedimentation tank and is discharged through the third outlet.

[0012] This invention replaces the external sedimentation system in existing AOA sludge dual-recirculation systems with an internal sedimentation tank. This not only significantly reduces the space occupied by the equipment but also effectively controls the residence time of activated sludge and the collection and utilization of functional biofilm sludge products. An inlet screen is installed on the baffle plate to prevent packing material and / or filter media from entering the internal sedimentation tank and causing losses.

[0013] Preferably, the upper part of the partition A of the first built-in sedimentation tank is provided with a first baffle plate, and the first outlet and the inlet screen A are respectively located on the upper and lower sides of the first baffle plate; the lower part of the partition A is inclined to form a first sludge hopper, and the bottom of the first sludge hopper is connected to the first sludge discharge pipe;

[0014] The second built-in sedimentation tank has a second baffle plate on the upper part of the baffle plate B, and the third outlet and the inlet screen B are located on the upper and lower sides of the second baffle plate respectively; the lower part of the baffle plate B is inclined to form a second sludge hopper, and the bottom of the second sludge hopper is connected to the second sludge discharge pipe.

[0015] The internal sedimentation tanks feature a clever and effective structural design. The first and second internal sedimentation tanks are equipped with inlet screens, baffles, sludge hoppers, and sludge discharge pipes, respectively. Baffles A and B separate the pre-biofilm anoxic tank and the post-biofilm anoxic tank into two water treatment spaces. The inlet screen has a moderate aperture, allowing water flow, sludge, and some detached biofilm to pass through, but restricting the entry of packing / filter media into the internal sedimentation tanks. The water fully contacts and reacts with the packing / filter media within the main spaces of the pre-biofilm anoxic tank and the post-biofilm anoxic tank. Within the built-in sedimentation tank, baffles divide it into upper and lower layers. The outlet and inlet screen are located on the upper and lower sides of the baffles, respectively. Preferably, the baffles are tilted downwards at an angle of 30-75° to the vertical. Water flows into the sedimentation tank through the inlet screen located on the lower side of the baffles. The water is guided downwards by the baffles, and the sludge deposited by the baffles collects in the sludge hopper, allowing the less dense supernatant to flow smoothly out through the outlet on the upper side of the baffles. The bottom of the first sludge hopper is connected to the first sludge discharge pipe, effectively controlling the residence time of activated sludge in the pre-biofilm anoxic tank. The bottom of the second sludge hopper is connected to the second sludge discharge pipe. The second sludge hopper is mainly used to deposit the biofilm sludge products detached during backwashing in the post-biofilm anoxic tank.

[0016] Preferably, the sludge return system includes a sludge return pipe connected to the second sludge discharge pipe, which returns at least a portion of the sludge to the pre-biofilm anoxic tank. A portion of the concentrated sludge discharged from the second sludge discharge pipe enters the sludge return pipe and is pumped back to the pre-biofilm anoxic tank, while the remaining portion is completely discharged. The concentrated sludge entering the sludge return pipe accounts for 20-50% of the total weight discharged from the second sludge discharge pipe. This process returns the sludge products from the sulfur autotrophic short-cut denitrification biofilm and anaerobic ammonia oxidation biofilm in the post-biofilm anoxic tank to the pre-biofilm anoxic tank for growth and enrichment.

[0017] Preferably, the effluent recirculation system includes an effluent recirculation pipe connected to a second built-in sedimentation tank, and the effluent recirculation pipe is connected to a pre-biofilm anoxic tank. More preferably, the effluent recirculation pipe is positioned above the second baffle plate. In addition to providing a sludge recirculation system to recirculate concentrated sludge to the pre-biofilm anoxic tank, this invention also provides an effluent recirculation system that recirculates effluent from the post-biofilm anoxic tank back to the pre-biofilm anoxic tank via an effluent recirculation pipe and a effluent recirculation pump at a recirculation ratio of 150-250%. This also continuously introduces sulfur elements, replenishing the sulfur source for the microorganisms and promoting denitrification. The recirculation ratio is calculated by dividing the effluent recirculation flow rate by the influent flow rate.

[0018] Compared with existing sludge dual-recirculation AOA devices and processes, the significant differences and advantages of this invention include at least the following:

[0019] The present invention does not involve activated sludge during normal operation, but rather a pure biofilm state.

[0020] The dual recirculation involved in this invention is not the two-stage (or two-part) recirculation of concentrated sludge in the sedimentation tank in existing dual recirculation AOA devices and processes. Instead, it involves the recirculation of a portion of the effluent and a portion of the detached biofilm. The former is to recirculate the remaining nitrate nitrogen and dissolved sulfur elements in the post-biofilm anoxic tank to the pre-biofilm anoxic tank to reduce total nitrogen; the latter is to recirculate the collected sulfur autotrophic short-cut denitrification biofilm and anaerobic ammonia oxidation biofilm after detachment to the pre-biofilm anoxic tank, thereby promoting sulfur autotrophic short-cut denitrification and anaerobic ammonia oxidation in the pre-anaerobic tank without adding sulfur filter media or inoculating anaerobic ammonia oxidation biofilm.

[0021] Therefore, this invention can overcome and break through the defects and technical bottlenecks of the traditional activated sludge process, bringing about a transformative development in urban wastewater treatment.

[0022] Preferably, the first, second, and third water distribution pipes extend into the bottom of each tank, and the biofilm aerobic tank is equipped with an aeration system. Extending the water distribution pipes into the bottom of each tank helps to prolong the water flow time within each treatment tank and creates disturbance within the tank due to the water flow from the distribution pipes, ensuring sufficient contact and treatment of the water by the packing material and / or filter media. The aeration system in the biofilm aerobic tank includes aeration pipes and / or aeration discs located at the bottom of the tank, and an aeration blower connected to the aeration pipes and / or aeration discs. This provides sufficient oxygen and aeration to the biofilm aerobic tank, promoting the growth and metabolism of aerobic microorganisms. Aerobic microorganisms can effectively digest organic matter, especially high-concentration organic wastewater, under aerobic conditions. Aeration in the aerobic tank provides sufficient oxygen and air bubbles to stimulate microbial growth and metabolism, promoting decomposition reactions and effectively degrading pollutants in the organic wastewater; it also enhances the activity of the biofilm. Aeration can continuously blow away the surface of the biofilm, keeping the biofilm active and inhibiting the proliferation of heterotrophic membranes. This can improve the utilization rate of oxygen. The oxygen from the bottom up can create turbulence in the water, allowing the biofilm attached to the packing material to continuously and evenly contact the water.

[0023] Preferably, the post-biofilm anoxic tank is equipped with a filter media support layer and a layer of elemental sulfur filter media on top of it, with the height of the elemental sulfur filter media layer being lower than the height of the inlet screen B of the second built-in sedimentation tank; and / or the post-biofilm anoxic tank has a backwashing system, including a backwash pipe and / or a backwash plate installed at the bottom of the tank. The initial volume ratio of the elemental sulfur filter media is 15-30%, and a biofilm will gradually form on its surface. When the elemental sulfur filter media with biofilm growth is found to have nitrite accumulation during the denitrification process through batch testing, anaerobic ammonia oxidation biofilm packing material with a volume ratio of 5-50% is added to the post-biofilm anoxic tank. Setting the height of the elemental sulfur filter media layer to be lower than the height of the inlet screen B ensures that the water effluent from the bottom distribution pipe fully contacts the elemental sulfur filter media before entering the second built-in sedimentation tank, which helps to save elemental sulfur filter media.

[0024] A backwashing blower is installed on the outer side of the bottom of the post-biofilm anoxic tank to provide backwash airflow to the backwash pipe and / or backfill plate. During the backwashing process, the biofilm in the sulfur-containing filter media and a small amount of anaerobic ammonia oxidation packing biofilm are backwashed into the water. The detached biofilm enters the second sludge hopper in the second built-in sedimentation tank. Then, the sludge return pump is turned on, and part of the concentrated sludge is returned to the pre-biofilm anoxic tank via the sludge return pipe. Subsequently, the sludge return pump is turned off, and the remaining concentrated sludge is discharged. This process returns the detached products of the sulfur autotrophic short-cut denitrification biofilm and anaerobic ammonia oxidation biofilm in the post-biofilm anoxic tank to the pre-biofilm anoxic tank for growth and enrichment.

[0025] Secondly, the present invention provides a method for enhanced nitrogen removal using the aforementioned sulfur autotrophic short-range denitrification coupled with anaerobic ammonia oxidation, comprising the following steps:

[0026] Step 1: Raw water enters the pre-biofilm anoxic tank through the first water distribution pipe. The packing material with biofilm uses the carbon source of the raw water to achieve denitrification and achieves mud-water separation in the first built-in sedimentation tank. The supernatant enters the first outlet.

[0027] Step 2: The supernatant enters the biofilm aerobic tank through the second water distribution pipe, where nitrification is achieved using oxygen, and the treated liquid enters the second effluent outlet;

[0028] Step 3: The treated liquid enters the post-biofilm anoxic tank through the third water distribution pipe. The elemental sulfur filter media with biofilm and the anaerobic ammonia-oxygen biofilm packing achieve sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation. The effluent is discharged through the third outlet and / or returned to the pre-biofilm anoxic tank through the effluent return system.

[0029] Preferably, before step one, a startup phase is included, comprising the following steps:

[0030] S1. Fill the anoxic and aerobic biofilm tanks with blank packing material, fill the anoxic biofilm tank with elemental sulfur filter material, and introduce activated sludge into the anoxic biofilm tank.

[0031] S2. Raw water is introduced, and a biofilm is formed on the blank packing material and elemental sulfur filter media, and activated sludge is discharged.

[0032] S3. After nitrite is generated in the post-biofilm anoxic tank through short-cut denitrification of the elemental sulfur filter media biofilm, anaerobic ammonia oxidation biofilm packing is added to the post-biofilm anoxic tank. Specifically, the biofilm on the elemental sulfur filter media uses the sulfur released from the filter media to reduce nitrate nitrogen in the aerobic tank effluent to nitrite.

[0033] This invention introduces activated sludge during the start-up phase, which takes 5-10 days to cultivate biofilms on the packing and filter media in each functional area. After that, the activated sludge is completely removed from the system, so that no activated sludge is involved during normal operation, and the system is in a pure biofilm state.

[0034] Preferably, the post-biofilm anoxic tank is backwashed periodically, including the following steps:

[0035] The backwash pipe and / or backwash plate at the bottom of the post-biofilm anoxic tank form a backwash gas-liquid flow, which backwashes and removes at least part of the biofilm of the sulfur elemental filter media and anaerobic ammonia oxidation biofilm packing material above it, and enters the second built-in sedimentation tank to form concentrated sludge. At least part of the concentrated sludge is returned to the pre-biofilm anoxic tank through the sludge return system.

[0036] The present invention has at least the following beneficial effects:

[0037] (1) This invention solves the problems of insufficient carbon source in urban sewage raw water and low utilization rate of carbon source in existing processes, which cannot achieve deep denitrification. During normal operation, the effluent ammonia nitrogen can be maintained below 0.5 mg / L, effluent nitrate nitrogen 1-3 mg / L, effluent nitrite nitrogen 0-0.5 mg / L, effluent TN below 5 mg / L, and effluent COD 12-47 mg / L. No carbon source addition is required, the COD removal rate reaches more than 80%, and the total nitrogen removal rate is more than 90%, realizing low-carbon, high-efficiency deep denitrification of urban sewage.

[0038] (2) This invention does not require the addition of an organic carbon source. It removes nitrogen through a sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation process. The autotrophic sludge production rate is low and it does not lead to an increase in effluent COD.

[0039] (3) By constructing a fully biofilm plug flow process, the hydraulic retention time in the biochemical section is reduced to 6-8 hours, and the land area is reduced by 30%-40%;

[0040] (4) Complete biofilms effectively avoid the vicious competition between autotrophic and heterotrophic bacteria, which is conducive to the screening, retention and enrichment of functional strains;

[0041] (5) The built-in sedimentation tank and reflux strategy effectively avoid the loss of sulfur autotrophic denitrification and anaerobic ammonia oxidation functional bacteria and the waste of sulfur filter media, save elemental sulfur filter media, and realize sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation in the plug flow multifunctional zone. Attached Figure Description

[0042] Figure 1 This is a schematic diagram of the structure of the sulfur autotrophic short-cut denitrification coupled anaerobic ammonia oxidation enhanced denitrification device of the present invention;

[0043] Attached reference numerals: 1.1 - Inlet pump; 1.2 - First distribution pipe; 1.3 - Second distribution pipe; 1.4 - Third distribution pipe; 1.5 - First sludge discharge pipe; 1.6 - Second sludge discharge pipe; 1.7 - Sludge return pipe; 1.8 - Tailwater return pipe; 2.1 - Pre-biofilm anoxic tank; 2.2 - Biofilm aerobic tank; 2.3 - Post-biofilm anoxic tank; 2.4 - First internal sedimentation tank; 2.4.1 - Inlet screen A; 2.4.2 - Baffle A 2.4.3 - First baffle plate; 2.4.4 - First sludge hopper; 2.5 - Second built-in sedimentation tank; 2.5.1 - Inlet screen B; 2.5.2 - Baffle B; 2.5.3 - Second baffle plate; 2.5.4 - Second sludge hopper; 2.6 - Third outlet; 2.7 - Tailwater return pump; 2.8 - Sludge return pump; 3.1 - Aeration blower; 3.2 - Backwash blower; 4.1 - Filter media support layer; 4.2 - Sulfur elemental filter media. Detailed Implementation

[0044] To better understand the above technical solutions, a detailed description of the solutions will be provided below in conjunction with the accompanying drawings and specific embodiments. Obviously, the described embodiments are merely some, not all, of the embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0045] The terminology used in the embodiments of this invention is for the purpose of describing particular embodiments only and is not intended to limit the invention. The singular forms “a,” “the,” and “the” as used in the embodiments of this invention and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.

[0046] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.

[0047] like Figure 1 As shown, a plug-flow type device with built-in sedimentation tank for sulfur autotrophic short-cut denitrification and anaerobic ammonia oxidation nitrogen removal includes:

[0048] (1) Pre-biofilm anoxic tank 2.1, which includes a first water distribution pipe 1.2 connected to a water source, a first internal sedimentation tank 2.4, and a first outlet. The first water distribution pipe 1.2 extends into the bottom of the pre-biofilm anoxic tank 2.1; the first internal sedimentation tank 2.4 is formed by a partition A2.4.2 with an inlet screen A2.4.1, and the first outlet is located above the first internal sedimentation tank 2.4. The first built-in sedimentation tank 2.4 has a first baffle plate 2.4.3 on the upper part of the baffle A2.4.2. The first outlet and the inlet screen A2.4.1 are located on the upper and lower sides of the first baffle plate 2.4.3, respectively. The lower part of the baffle plate A2.4.2 is inclined to form a first sludge hopper 2.4.4, and the bottom of the first sludge hopper 2.4.4 is connected to the first sludge discharge pipe 1.5. The first built-in sedimentation tank 2.4 achieves sludge-water separation. The settled sludge is discharged, and the supernatant is discharged through the first outlet and enters the biofilm aerobic tank 2.2. Preferably, the first baffle plate 2.4.3 is inclined downward to guide the water flowing into the built-in sedimentation tank 2.4 from the inlet screen A2.4.1 downward. The sludge deposited by the baffle plate gathers in the first sludge hopper 2.4.4, so that the less dense clear liquid flows out smoothly from the outlet on the upper side of the baffle plate 2.4.3.

[0049] (2) Biofilm aerobic tank 2.2, which includes a second water distribution pipe 1.3 connected to the first outlet and a second outlet, and also includes an aeration blower 3.1 connected to the bottom of the biofilm aerobic tank 2.2; the second water distribution pipe 1.3 extends into the bottom of the biofilm aerobic tank 2.2, where the biofilm uses oxygen to achieve nitrification and ensures that there is 2-3 mg / L of ammonia nitrogen remaining; then it enters the post-biofilm anoxic tank 2.3 from the second outlet.

[0050] (3) Post-biofilm anoxic tank 2.3, which includes a third water distribution pipe 1.4 connected to the second outlet, a second internal sedimentation tank 2.5, and a third outlet. The third water distribution pipe 1.4 extends into the bottom of the post-biofilm anoxic tank 2.3. The second internal sedimentation tank 2.5 is enclosed by a partition B2.5.2 with an inlet screen B2.5.1, and the third outlet is located above the second internal sedimentation tank 2.5. The upper part of the partition B2.5.2 of the second internal sedimentation tank 2.5 is provided with a second baffle 2.5.3, and the third outlet and the inlet screen B2.5.1 are located on the upper and lower sides of the second baffle 2.5.3, respectively; the lower part of the partition B2.5.2 is inclined to form a second sludge hopper 2.5.4, and the bottom of the second sludge hopper 2.5.4 is connected to the second sludge discharge pipe 1.6. It also includes a tailwater return pipe 1.8 disposed above the second baffle plate 2.5.3, which is connected to the pre-biofilm anoxic tank 2.1 via a tailwater return pump 2.7. Preferably, the second baffle plate 2.5.3 is inclined downwards to guide the water flowing into the built-in sedimentation tank 2.5 from the inlet screen B2.5.1 downwards. The sludge deposited by the baffle is collected in the second sludge hopper 2.5.4, allowing the less dense supernatant to flow smoothly out from the outlet on the upper side of the baffle plate 2.5.3. The second sludge discharge pipe 1.6 is connected to the sludge return pipe 1.7, and at least a portion of the sludge is returned to the pre-biofilm anoxic tank 2.1 via the sludge return pump 2.8. The concentrated sludge entering the sludge return pipe 1.7 accounts for 20-50% of the total weight discharged by the second sludge discharge pipe 1.6.

[0051] The post-biofilm anoxic tank 2.3 is equipped with a filter media support layer 4.1 and a sulfur-containing filter media layer 4.2 on top of it. The height of the sulfur-containing filter media layer 4.2 is lower than the height of the influent screen B2.5.1 of the second built-in sedimentation tank 2.5. The elemental sulfur filter media biofilm and the anaerobic ammonia oxidation biofilm achieve sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation. The final effluent, after passing through the second built-in sedimentation tank 2.5, is discharged through the third outlet and / or returned to the pre-biofilm anoxic tank 2.1 through the effluent return pipe 1.8. The effluent from the post-biofilm anoxic tank 2.3 is returned to the pre-biofilm anoxic tank 2.1 by the effluent return pump 2.7 at a return ratio of 150-250%, which will continuously introduce sulfur elements, replenish the sulfur source for the microorganisms there, and promote the denitrification reaction.

[0052] The post-biofilm anoxic tank 2.3 has a backwashing system, including a backwash pipe and / or backwash plate installed at the bottom of the tank.

[0053] The preferred volume ratio of the pre-biofilm anoxic tank, the biofilm aerobic tank, and the post-biofilm anoxic tank is 1:1:1. Each of the above tanks is filled with biofilm-containing packing material and / or filter media, accounting for 20-80% of the total volume.

[0054] A method for enhanced nitrogen removal via sulfur autotrophic short-cut denitrification coupled with anaerobic ammonium oxidation includes the following steps:

[0055] (1) Start-up phase:

[0056] S1. Fill the pre-biofilm anoxic tank 2.1 and biofilm aerobic tank 2.2 with blank packing material accounting for 20-80% of the volume, fill the post-biofilm anoxic tank 2.3 with elemental sulfur filter material accounting for 15-30% of the volume, and introduce activated sludge into the pre-biofilm anoxic tank 2.1.

[0057] S2. Raw water is introduced, and a biofilm is formed on the blank packing material and elemental sulfur filter media, and activated sludge is discharged.

[0058] S3. After nitrite is generated in the post-biofilm anoxic tank under the short-range denitrification of the elemental sulfur filter biofilm, anaerobic ammonia oxidation biofilm packing material with a volume ratio of 5-50% is added to the post-biofilm anoxic tank 2.3.

[0059] (2) Normal operation phase

[0060] Step 1: Raw water enters the pre-biofilm anoxic tank 2.1 through the first water distribution pipe 1.2 via the inlet pump 1.1. The packing material with biofilm uses the carbon source of the raw water to achieve denitrification and achieves mud-water separation in the first built-in sedimentation tank 2.4. The supernatant enters the first outlet.

[0061] Step 2: The supernatant enters the biofilm aerobic tank 2.2 through the second water distribution pipe 1.3, where nitrification is achieved using oxygen, and the treated liquid enters the second effluent outlet;

[0062] Step 3: The treated liquid enters the post-biofilm anoxic tank 2.3 through the third water distribution pipe 1.4. The elemental sulfur filter media with biofilm and the anaerobic ammonia-oxygen biofilm packing achieve sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation. The effluent is discharged through the third outlet and / or returned to the pre-biofilm anoxic tank 2.1.

[0063] Under this virtuous cycle, the biofilm in the pre-biofilm anoxic tank 2.1 will utilize the organic carbon source in the raw water and the sulfur element from the effluent return to achieve the coupling of heterotrophic partial short-cut denitrification, sulfur autotrophic partial short-cut denitrification, and anaerobic ammonia oxidation; the biofilm aerobic tank 2.2 continues to achieve nitrification and control the remaining ammonia nitrogen; the post-biofilm anoxic tank 2.3 will exert the coupling effect of sulfur autotrophic denitrification, sulfur autotrophic partial short-cut denitrification, and anaerobic ammonia oxidation, achieving a COD removal rate of over 80% and a total nitrogen removal rate of over 90%.

[0064] (3) Enhanced process operation measures: The post-biofilm anoxic tank 2.3 is backwashed regularly, including the following steps:

[0065] The backwash blower 3.2 on the outer side of the bottom of the post-biofilm anoxic tank 2.3 is started, and the backwash pipe and / or backwash plate form a backwash gas-liquid flow from the bottom of the tank upwards. This backwashes and removes at least part of the biofilm from the sulfur-based filter media and anaerobic ammonia oxidation biofilm packing material above the tank, which then enters the second built-in sedimentation tank 2.5 to form concentrated sludge. After 30 minutes, the sludge return pump 2.8 is turned on, and 20-50% of the concentrated sludge is returned to the pre-biofilm anoxic tank 2.1 through the sludge return pipe 1.7. Subsequently, the sludge return pump 2.8 is turned off, and the remaining concentrated sludge is discharged through the second sludge discharge pipe 1.6. This process returns the products of the sulfur autotrophic short-range denitrification biofilm and anaerobic ammonia oxidation biofilm in the post-biofilm anoxic tank 2.3 to the pre-biofilm anoxic tank 2.1 for growth and enrichment. Meanwhile, the effluent from the post-biofilm anoxic tank 2.3 is returned to the pre-biofilm anoxic tank via the effluent return pump 2.7 at a return ratio of 150-250%, which will continuously introduce sulfur elements. Example

[0066] like Figure 1 As shown, a plug-flow type built-in sedimentation tank for sulfur autotrophic short-cut denitrification anaerobic ammonia oxidation nitrogen removal includes a pre-biofilm anoxic tank 2.1, a biofilm aerobic tank 2.2, and a post-biofilm anoxic tank 2.3 connected in sequence, with a volume ratio of 1:1:1 between the pre-biofilm anoxic tank 2.1, the biofilm aerobic tank 2.2, and the post-biofilm anoxic tank 2.3. Each tank is filled with packing material and / or filter media. The specific structure includes:

[0067] (1) A pre-biofilm anoxic tank 2.1 includes a first water distribution pipe 1.2 connected to a water source, a first internal sedimentation tank 2.4, and a first outlet, and approximately 50 v / v% packing material is added. The first water distribution pipe 1.2 extends into the bottom of the pre-biofilm anoxic tank 2.1. The first internal sedimentation tank 2.4 includes an inlet screen A2.4.1, a first baffle plate 2.4.3, a first sludge hopper 2.4.4, and a first sludge discharge pipe 1.5, which are enclosed by a partition A2.4.2 having the inlet screen A2.4.1, and the first outlet is located above the first internal sedimentation tank 2.4. The first built-in sedimentation tank 2.4 has a baffle plate 2.4.3 installed on the upper part of the baffle A2.4.2. The first outlet and the inlet screen A2.4.1 are located on the upper and lower sides of the first baffle plate 2.4.3, respectively. The first baffle plate 2.4.3 is inclined downwards at a 60° angle to the vertical direction, which facilitates smooth flow and prevents the deposition of dirt. The lower part of the baffle A2.4.2 is inclined to form a first sludge hopper 2.4.4, and the bottom of the first sludge hopper 2.4.4 is connected to the first sludge discharge pipe 1.5. The first built-in sedimentation tank 2.4 achieves sludge-water separation. The settled sludge is discharged, and the supernatant is discharged through the first outlet and enters the biofilm aerobic tank 2.2.

[0068] (2) Biofilm aerobic tank 2.2 includes a second water distribution pipe 1.3 connected to the first outlet and a second outlet, and also includes an aeration blower 3.1 connected to the bottom of biofilm aerobic tank 2.2, and about 70v / v% of packing material is added; the second water distribution pipe 1.3 extends into the bottom of biofilm aerobic tank 2.2, where the biofilm uses oxygen to achieve nitrification and ensures that there is 2-3 mg / L of ammonia nitrogen remaining; then it enters the post-biofilm anoxic tank 2.3 from the second outlet.

[0069] (3) The post-biofilm anoxic tank 2.3 includes a third water distribution pipe 1.4 connected to the second outlet, a second internal sedimentation tank 2.5 and a third outlet, and 20v / v% elemental sulfur filter media and 40v / v% anaerobic ammonia oxidation biofilm packing are added successively. The third water distribution pipe 1.4 extends into the bottom of the post-biofilm anoxic tank 2.3.

[0070] The second built-in sedimentation tank 2.5 includes an inlet screen B2.5.1, a second baffle plate 2.5.3, a second sludge hopper 2.5.4, and a second sludge discharge pipe 1.6, all enclosed by a partition B2.5.2 containing the inlet screen B2.5.1. A third outlet is located above the second built-in sedimentation tank 2.5. The second baffle plate 2.5.3 is located on the upper part of the partition B2.5.2 of the second built-in sedimentation tank 2.5. The third outlet and the inlet screen B2.5.1 are located on the upper and lower sides of the second baffle plate 2.5.3, respectively. The second baffle plate 2.5.3 is inclined downwards at a 60° angle to the vertical direction, ensuring smooth flow and preventing the accumulation of dirt. The lower part of the partition B2.5.2 is inclined to form the second sludge hopper 2.5.4, and the bottom of the second sludge hopper 2.5.4 is connected to the second sludge discharge pipe 1.6. It also includes a tailwater return pipe 1.8 disposed above the second baffle 2.5.3, which is connected to the pre-biofilm anoxic tank 2.1 via a tailwater return pump 2.7. A second sludge discharge pipe 1.6 is connected to the sludge return pipe 1.7, and at least a portion of the sludge is returned to the pre-biofilm anoxic tank 2.1 via the sludge return pump 2.8. The concentrated sludge entering the sludge return pipe 1.7 accounts for 30% of the total weight discharged through the second sludge discharge pipe 1.6.

[0071] The post-biofilm anoxic tank 2.3 is equipped with a filter media support layer 4.1 and a sulfur-containing filter media layer 4.2 on top of it. The volume of the sulfur-containing filter media layer 4.2 accounts for approximately 20% of the total volume of the post-biofilm anoxic tank 2.3, and its height is lower than the height of the influent screen B2.5.1 of the second built-in sedimentation tank 2.5. The elemental sulfur filter media biofilm and the anaerobic ammonia oxidation biofilm achieve sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation. The final effluent, after passing through the second built-in sedimentation tank 2.5, is discharged through the third outlet and / or returned to the pre-biofilm anoxic tank 2.1 through the effluent return pipe 1.8. The effluent from the post-biofilm anoxic tank 2.3 is returned to the pre-biofilm anoxic tank 2.1 by the effluent return pump 2.7 at a return ratio of 200%, which will continuously introduce sulfur elements, replenish the sulfur source for the microorganisms therein, and promote the denitrification reaction.

[0072] The post-biofilm anoxic tank 2.3 has a backwashing system, including a backwash pipe and a backwash plate installed at the bottom of the tank, and a backwash blower 3.2 installed on the outside of the bottom of the post-biofilm anoxic tank. The post-biofilm anoxic tank 2.3 is backwashed periodically. During the backwashing process, the biofilm in the sulfur elemental filter media and a small amount of anaerobic ammonia oxidation packing biofilm are backwashed into the water, and the above materials are returned to the pre-biofilm anoxic tank 2.1 by the sludge return system and the tailwater return system.

[0073] The specific operating method is as follows:

[0074] (1) Process start-up stage

[0075] The volume ratio of the pre-biofilm anoxic tank 2.1, the biofilm aerobic tank 2.2, and the post-biofilm anoxic tank 2.3 was set at 1:1:1. In this example, the influent COD was 60.3-234.8 mg / L, ammonia nitrogen concentration was 30.9-45.4 mg / L, total nitrogen concentration was 33.4-50 mg / L, and the carbon-to-nitrogen ratio was 2-5. 50v / v% blank packing material was added to the pre-biofilm anoxic tank 2.1, and 70v / v% blank packing material was added to the biofilm aerobic tank 2.2, allowing the packing material to flow through agitation. 20v / v% elemental sulfur filter media was added to the post-biofilm anoxic tank 2.3. First, 3500 mg / L of activated sludge was introduced into the pre-biofilm anoxic tank 2.1, and after 10 days, a biofilm formed on the packing material and filter media in each functional zone. Subsequently, the activated sludge was completely discharged from the system.

[0076] (2) During normal operation

[0077] Raw water is sequentially fed into the pre-biofilm anoxic tank 2.1, the biofilm aerobic tank 2.2, and the post-biofilm anoxic tank 2.3 via inlet pump 1.1, first distribution pipe 1.2, second distribution pipe 1.3, and third distribution pipe 1.4, with a hydraulic retention time of 6 hours. When batch testing shows nitrite accumulation during denitrification on the elemental sulfur filter media with biofilm growth, 40v / v% anaerobic ammonia oxidation biofilm packing is added to the post-biofilm anoxic tank. Specifically, raw water enters the pre-biofilm anoxic tank 2.1 via inlet pump 1.1 and first makeup water pipe 1.2, flowing upwards from the bottom. After interacting with the packing material in the tank, it enters the first built-in sedimentation tank 2.4 through inlet screen A2.4.3. Guided by the first baffle plate 2.4.3, the denser sludge mixture settles and accumulates in the first sludge hopper 2.4.4 and is discharged through the first sludge discharge pipe 1.5. The less dense clear liquid collects on the upper side of the first baffle plate 2.4.3 and flows into the second distribution pipe 1.3 through the first outlet, entering the biofilm aerobic tank 2.2. Water flows upwards from the bottom, while the aeration blower 3.1 injects a large amount of oxygen into the tank through the aeration plate. The water interacts with the packing material and oxygen in the tank, allowing the biofilm to achieve nitrification using oxygen, ensuring a 2-3% oxygen content. The residual ammonia nitrogen is mg / L. The water flows through the second outlet into the third-step water pipe 1.4 and enters the post-biofilm anoxic tank 2.3. The water is released from the bottom upwards and undergoes sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation through the elemental sulfur filter biofilm and anaerobic ammonia oxidation biofilm in the tank. The water then enters the second built-in sedimentation tank 2.5 through the inlet screen B2.5.3 and is guided by the second baffle plate 2.5.3. The higher density mixture settles and accumulates in the second sludge hopper 2.5.4, while the lower density effluent collects on the upper side of the second baffle plate 2.5.3 and is discharged through the third outlet. It is also / or returned to the pre-biofilm anoxic tank 2.1 by the effluent return pump 2.7 at a return ratio of 200%. The continuous introduction of sulfur elements into the pre-biofilm anoxic tank 2.1 is beneficial for further reducing nitrate nitrogen in the post-biofilm anoxic tank 2.3.

[0078] In the current stage, the biofilm in the pre-biofilm anoxic tank 2.1 utilizes the carbon source of the raw water to achieve denitrification. The wastewater achieves sludge-water separation in the first built-in sedimentation tank, and the settled sludge is discharged through the first sludge discharge pipe 1.5. The supernatant enters the biofilm aerobic tank 2.2, where the biofilm utilizes oxygen to achieve nitrification and ensures a residual ammonia nitrogen level of 2-3 mg / L. Subsequently, the effluent enters the post-biofilm anoxic tank 2.3, where the elemental sulfur filter biofilm and the anaerobic ammonia oxidation biofilm achieve sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation.

[0079] (3) Enhanced process operation measures

[0080] During operation, the post-biofilm anoxic tank 2.3 is backwashed weekly. During backwashing, the biofilm from the sulfur-containing filter media and a small amount of anaerobic ammonia oxidation packing biofilm are backwashed into the water. The detached biofilm enters the second sludge hopper 2.5.4 in the second internal sedimentation tank 2.5. After 30 minutes, the sludge return pump 2.8 is turned on, returning 30% of the concentrated sludge to the pre-biofilm anoxic tank via the sludge return pipe 1.7. Then, the sludge return pump 2.8 is turned off, and the remaining 70% of the concentrated sludge is discharged via the second sludge discharge pipe 1.6. This process returns the detached products of the sulfur-autotrophic short-cut denitrification biofilm and anaerobic ammonia oxidation biofilm from the post-biofilm anoxic tank 2.3 to the pre-biofilm anoxic tank 2.1 for growth and enrichment. Simultaneously, the effluent from the post-biofilm anoxic tank 2.3 is returned to the pre-biofilm anoxic tank via the effluent return pump 2.7 at a 200% return ratio, continuously introducing sulfur elements. This stage adopts a double reflux mode, which is a special mode of normal operation. The purpose is to return the biofilm carrying sulfur-autotrophic denitrifying bacteria and anaerobic ammonia oxidizing bacteria, as well as a small amount of sulfur filter media, to the pre-anoxic tank for use by the pre-anoxic tank.

[0081] (4) Process stabilization stage

[0082] Under this virtuous cycle, the biofilm in the pre-biofilm anoxic tank 2.1 utilizes the organic carbon source in the raw water and the sulfur element from the effluent return to achieve the coupling of heterotrophic partial short-cut denitrification, sulfur autotrophic partial short-cut denitrification, and anaerobic ammonia oxidation; the biofilm aerobic tank 2.2 continues to achieve nitrification and control ammonia nitrogen residue; the post-biofilm anoxic tank 2.3 plays a role in sulfur autotrophic denitrification, sulfur autotrophic partial short-cut denitrification coupled with anaerobic ammonia oxidation. The system hydraulic retention time is approximately 6-8 hours, and the ammonia nitrogen residue in the biofilm aerobic tank 2.2 is maintained at 2-5 mg / L. During normal operation, the effluent ammonia nitrogen can be maintained below 0.5 mg / L, effluent nitrate nitrogen 1-3 mg / L, effluent nitrite nitrogen 0-0.5 mg / L, effluent TN below 5 mg / L, and effluent COD 12-47 mg / L. No carbon source needs to be added, the COD removal rate reaches more than 80%, and the total nitrogen removal rate is more than 90%, achieving low-carbon, high-efficiency, and deep denitrification of urban sewage.

[0083] Although preferred embodiments of the invention have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including both the preferred embodiments and all changes and modifications falling within the scope of the invention. Clearly, those skilled in the art can make various alterations and modifications to the invention without departing from its spirit and scope. Thus, if these modifications and modifications of the invention fall within the scope of the claims and their equivalents, the invention is also intended to include these modifications and modifications.

Claims

1. A plug flow built-in sedimentation tank sulfur autotrophic shortcut denitrification anaerobic ammonia oxidation nitrogen removal device, characterized in that, The system comprises a front biofilm anoxic tank, a biofilm aerobic tank and a rear biofilm anoxic tank connected in sequence, each tank is filled with 20-80% volume ratio of filler and / or filter material with biofilm, the front biofilm anoxic tank and the rear biofilm anoxic tank are respectively provided with an internal sedimentation tank, the rear biofilm anoxic tank and the front biofilm anoxic tank are provided with a sludge return system and a tail water return system; The front biofilm anoxic tank comprises a first water distribution pipe connected with an inlet, a first internal sedimentation tank and a first water outlet, the first internal sedimentation tank is surrounded by a partition A with an inlet screen A, and the first water outlet is above the first internal sedimentation tank; The biofilm aerobic tank comprises a second water distribution pipe connected with the first water outlet and a second water outlet; The rear biofilm anoxic tank comprises a third water distribution pipe connected with the second water outlet, a second internal sedimentation tank and a third water outlet, the second internal sedimentation tank is surrounded by a partition B with an inlet screen B, and the third water outlet is above the second internal sedimentation tank; The rear biofilm anoxic tank is filled with elemental sulfur filter material and anaerobic ammonia oxidation biofilm filler to realize sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation.

2. The apparatus of claim 1, wherein, The partition A of the first internal sedimentation tank is provided with a first baffle plate at the upper part, the first water outlet and the inlet screen A are respectively located on the upper and lower sides of the first baffle plate, and the lower part of the partition A is inclined to form a first sludge hopper, and the bottom of the first sludge hopper is connected with a first sludge discharge pipe; The partition B of the second internal sedimentation tank is provided with a second baffle plate at the upper part, the third water outlet and the inlet screen B are respectively located on the upper and lower sides of the second baffle plate, and the lower part of the partition B is inclined to form a second sludge hopper, and the bottom of the second sludge hopper is connected with a second sludge discharge pipe.

3. The apparatus of claim 2, wherein, The sludge return system comprises a sludge return pipe connected with the second sludge discharge pipe, and at least part of the sludge is returned to the front biofilm anoxic tank.

4. The apparatus of claim 2, wherein, The tail water return system comprises a tail water return pipe connected with the second internal sedimentation tank, and the tail water return pipe is connected with the front biofilm anoxic tank.

5. The device of any one of claims 1-4, wherein, The first water distribution pipe, the second water distribution pipe and the third water distribution pipe respectively extend into the bottom of each tank, and the biofilm aerobic tank is provided with an aeration system.

6. The device of any one of claims 1-4, wherein, The rear biofilm anoxic tank is provided with a filter material supporting layer and an elemental sulfur filter material layer thereon, the height of the elemental sulfur filter material layer is lower than the height of the inlet screen B of the second internal sedimentation tank, and / or the rear biofilm anoxic tank is provided with a backwashing system comprising a backwashing pipe and / or a backwashing plate arranged at the bottom of the tank.

7. A sulfur autotrophic shortcut denitrifying ANAMMOX process for nitrogen removal using the device according to any one of claims 1 to 6, characterized in that, The method comprises the following steps: Step one: raw water enters the front biofilm anoxic tank through the first water distribution pipe, the filler with biofilm realizes denitrification by using carbon source of raw water, and realizes sludge-water separation in the first internal sedimentation tank, and the supernatant enters the first water outlet; Step two: the supernatant enters the biofilm aerobic tank through the second water distribution pipe, realizes nitrification by using oxygen, and the treated liquid enters the second water outlet; Step three: the treated liquid enters the rear biofilm anoxic tank through the third water distribution pipe, the elemental sulfur filter material and the anaerobic ammonia oxidation biofilm filler with biofilm realize sulfur autotrophic short-cut denitrification coupled with anaerobic ammonia oxidation, and the tail water is discharged through the third water outlet and / or returned to the front biofilm anoxic tank through the tail water return system.

8. The method of claim 7, wherein, Before step one, a start-up stage is further included, which comprises the following steps: S1, filling blank filler into the front biofilm anoxic tank and the biofilm aerobic tank, filling elemental sulfur filter into the rear biofilm anoxic tank, and introducing activated sludge into the front biofilm anoxic tank; S2, introducing raw water, forming biofilm on the blank filler and the elemental sulfur filter, and discharging activated sludge; S3, after the rear biofilm anoxic tank generates nitrite under the short-cut denitrification of the biofilm on the elemental sulfur filter, introducing anaerobic ammonia oxidation biofilm filler into the rear biofilm anoxic tank.

9. The method of claim 7 or 8, wherein, The rear biofilm anoxic tank is periodically back-flushed, including the following steps: The back-flushing pipe and / or back-flushing plate at the bottom of the rear biofilm anoxic tank form a back-flushing gas-liquid flow, which back-flushes and removes at least part of the biofilm on the elemental sulfur filter and the anaerobic ammonia oxidation biofilm filler above, and enters the second built-in sedimentation tank to form concentrated sludge, and the sludge backflow system back-flows at least part of the concentrated sludge to the front biofilm anoxic tank.

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