30results about How to "Save aeration" patented technology

The invention discloses a low-oxygen aerating control device and method of segment inlet A / O biological denitrifying technique, which contains three control circuits, wherein the first and second circuits adopt DO cascade PI control system; the third circuit uses higher-precision ammonia nitrogen feedforward-feedback control system, which gathers DO density, ammonia nitrogen density of aerobic area and ammonia nitrogen density of last anoxybiotic area to reflect the change of inlet load.

The invention discloses a device and a method for a low-C / N ratio municipal wastewater short-cut denitrification / short-cut nitrification anaerobic ammonia oxidation biofilm process, belonging to the field of biological sewage treatment. The method comprises the following steps: allowing municipal wastewater and one part of supernatant subjected to short-cut nitrification anaerobic ammonia oxidation in the previous cycle to simultaneously enter a short-cut denitrification bio-membrane reactor, performing anaerobic stirring, performing short-cut denitrification by fully utilizing a carbon source in raw water, and reducing NO3<-> into NO2<->, so that the influence of organic matters in the raw water on microbes in the subsequent short-cut nitrification anaerobic ammonia oxidation bio-membrane reactor; and pumping the supernatant containing NH4<+> and NO2<-> into the short-cut nitrification anaerobic ammonia oxidation bio-membrane reactor through a peristaltic pump for carrying out an anaerobic ammonia oxidation reaction, performing short-cut nitrification and anaerobic ammonia oxidation on the residual NH4<+> in an intermittent aeration and intermittent stirring manner, and finally draining. According to the method disclosed by the invention, the carbon source does not need to be added, advanced nitrogen removal of the low-C / N ratio municipal wastewater is realized, and the method has the advantages of energy consumption, small treatment amount of residual sludge, and the like.

The invention discloses an AAO (Anaerobic-Anoxic-Oxic)-biological contact oxidation strengthened denitrification and dephosphorization device and a real-time control method of low C / N sewage treatment. The system is mainly composed of a raw water tank, an AAO reactor, an intermediate sedimentation tank, a biological contact oxidation tank, a settling zone, a discharged water tank, an online control box and a computer. The real-time control method is as follows: a DO sensor online collects concentrations of dissolved oxygen in grid cells of the biological contact oxidation tank, and the computer calculates and outputs the concentrations to control the nitrification process; a NH<4+> sensor, a NO<3-> sensor, a NO<2-> sensor and a TP sensor online collect the concentrations of ammonia nitrogen, nitrate, nitrite and total phosphorus in the discharged water tank, and the computer calculates and outputs according to the signals collected by the sensors to adjust the aeration amount, the reflux ratio of nitrifying liquid and water intake C / N. By adopting the online real-time control equipment, the system operation is optimized, the energy is saved, the consumption is reduced, the carbon source and the aeration amount are saved and the residual sludge is reduced.

The invention relates to an A2 / O-bio-contact oxidation device and method based on coupling of partial nitrification and denitrifying phosphorous removal and belongs to the field of biological treatment of sewage. The device mainly comprises an A2 / O reactor (comprising an anaerobic zone, an anoxic zone and an aerobic zone), a wobble plate sedimentation tank, a biological contact oxidation tank and a sedimentation zone, wherein the aerobic zone of the A2 / O reactor is connected with the wobble plate sedimentation tank by virtue of an overflow baffle, the wobble plate sedimentation tank is connected with the biological contact oxidation tank, and the biological contact oxidation tank is connected with the sedimentation zone; filler made from carbon fibers is arranged in the biological contact oxidation tank and is mainly used for completing partial nitrification; a sludge reflux pump is communicated with the bottom of the anaerobic zone of the A2 / O reactor, a nitrification liquor reflux pump is connected with an effluent tank and the anoxic zone of the A2 / O reactor to realize denitrifying phosphorus removal. The A2 / O-bio-contact oxidation device and method fully take advantages of partial nitrification and denitrifying phosphorous removal and have the advantages of conservation of carbon source, low aeration rate, low sludge yield and the like.

The invention discloses a domestic sewage integrated anaerobic ammonia oxidation-strengthened endogenous denitrification SBBR control system, and belongs to the field of biological sewage treatment. The system comprises a water tank and an SBBR reactor; after domestic sewage enters the SBBR reactor, denitrifying bacteria achieve a denitrifying effect by utilizing organic matters in the sewage, and redundant organic matters are stored in vivo to synthesize an internal carbon source; micro-aeration is started after the reaction is ended; integrated anaerobic ammonia oxidation reaction is performed on a biological membrane; a DO sensor, a NH4<+> sensor, a NO2 sensor and a NO3 sensor acquire signals online, the DO concentration is controlled and the reaction time is adjusted via computer output; after the aeration is completed, anoxic endogenous denitrification is performed, the concentration of nitrate nitrogen of outlet water is reduced, and static settling is performed and water is discharged after the reaction is completed. According to the domestic sewage integrated anaerobic ammonia oxidation-strengthened endogenous denitrification SBBR control system, the technical advantages of the SBBR system and integrated anaerobic ammonia oxidation are played; the organic matters in the sewage are utilized, so that the SBBR control system has the characteristics of energy conservation, consumption reduction and impact load resistance; meanwhile, the system operation is optimized via online real-time control; the automation degree is high; the controllability is high; advanced nitrogen removal can be realized.

The invention discloses an enhanced nitrogen and phosphorus removal device and method for low-carbon sewage. The enhanced nitrogen and phosphorus removal device comprises a biosorption tank, a sedimentation tank, a nitration reaction tank, an anoxic denitrification tank, a secondary aeration tank and a secondary sedimentation tank which are sequentially connected through pipes, and also comprisesa sludge regeneration tank, wherein the biosorption tank is connected with a short-generation sludge feeding device through a pipe; a sediment outlet of the sedimentation tank is connected with the sludge regeneration tank and the anoxic denitrification tank through pipes, and the sludge regeneration tank is connected with the biosorption tank through a pipe; a sludge outlet of the secondary sedimentation tank is connected with the nitration reaction tank through a pipe; an aeration device is arranged on each of the nitration reaction tank, the secondary aeration tank and the sludge regeneration tank. The invention further discloses an enhanced nitrogen and phosphorus removal method for the low-carbon sewage. By using the device for treating the low-carbon sewage, the utilization efficiency of a carbon source can be improved, biological nitrogen and phosphorus removal capability of the device is enhanced, and the operation cost of a sewage treatment plant can be reduced.

The invention discloses a synchronous nitrogen and phosphorus removal sewage treatment process. The treatment process comprises two parts of chemical phosphorus removal and biological nitrogen removal, wherein biological nitrogen removal is divided into a heterotrophic denitrification process and an autotrophic denitrification process, and all sludge subjected to biological nitrogen removal returns to a chemical phosphorus removal section. By means of the treatment process, the continuity of nitrogen and phosphorus removal is achieved, the dosage of added chemicals is reduced, and the cost isreduced.

The invention discloses a method and device for realizing advanced nitrogen and phosphorus removal of low-carbon-nitrogen-ratio domestic sewage by adopting a step-feed double-short-range anaerobic ammonia oxidation process, and belongs to the field of biological sewage treatment. The device comprises an urban domestic sewage raw water tank, a double-short-range anaerobic ammonia oxidation reactor and a water outlet tank. Urban domestic sewage enters the integrated reactor in batches and then runs in anoxic and aerobic modes, short-cut denitrification coupling anaerobic ammonia oxidation reaction and phosphorus release occur in an anoxic section, synchronous short-cut nitrification coupling anaerobic ammonia oxidation reaction and phosphorus uptake occur in an aerobic section, and a biological carrier is arranged in the reactor to better retain anaerobic ammonia oxidation bacteria, so that double short-range anaerobic ammonia oxidation is stably realized in the integrated SBR reactor, and advanced nitrogen and phosphorus removal is achieved.

The invention discloses a domestic sewage treatment process. Each cell of a grille board used in the step (1) is 1.5 cm, and the grille board in the specification can isolate most of floating rubbish in water; a coagulant used in the step (2) is polymeric aluminum chloride, the efficient water purifier can have an effective coagulating sedimentation effect on insoluble particles in the water; the temperature during anaerobic treatment in the step (3) is set to rise in a gradient manner and is 20 DEG C in the first half period and 8 DEG C in the later half period, the first half period of anaerobic treatment is the microorganism growth period, the later half period is the treatment period, accordingly, the temperature in the first half period is high and facilitates growth of anaerobic bacteria, and the temperature in the later half period is low and facilitates treatment of waste water through the anaerobic bacteria; the aeration mode in the step (4) is intermittent aeration, aeration is suspended for 24 h after aeration is performed for 24 h and facilitates growth of aerobic bacteria, and accordingly, useless aeration can be reduced according to the growth cycle of the bacteria and the treatment cycle; filtration in the step (5) is ultrafiltration, pressure applied to the water is 0.5 Mpa, and the purification speed of the water can be increased through ultrafiltration.

The invention relates to the field of sewage treatment, in particular to a consumption reduction and efficiency improvement system and method suitable for oxidation ditch biological denitrification. The system is characterized by comprising a biological reaction zone which is divided into a non-aeration zone and an aeration zone, and a water inlet which is communicated with a water inlet pump through a sewage inlet pipe, wherein a sewage flow meter is arranged on the sewage inlet pipe, a nitrate nitrogen probe and an ORP probe are arranged in the non-aeration area, and an ammonia nitrogen probe and a DO probe are further arranged in the aeration area. The system further comprises a carbon source storage tank with a carbon source, the carbon source storage tank is communicated with the non-aeration area through a carbon source feeding pipe, and a flow control valve and a flow meter are sequentially arranged on the carbon source feeding pipe; and the water inlet pump, the sewage flow meter, the nitrate nitrogen probe, the ORP probe, the ammonia nitrogen probe, the DO probe, the flow regulating valve and the flow meter are respectively in communication connection with a PLC. Through the system and the method, the aeration rate and the carbon source addition amount during the biological denitrification process can be accurately controlled, and the balance between the nitrificationand the denitrification is controlled to improve the sewage treatment effect.

The invention discloses a powerless sewage purification device which comprises a shell, a coarse screen, a fine filtering layer, a collecting tank and a biological activated carbon trickling filter. The powerless sewage purification device is characterized in that the coarse screen is arranged at the upper part of the fine filtering layer; the biological activated carbon trickling filter is arranged at the lower part of the fine filtering layer; the coarse screen and the fine filtering layer are inclined to the collecting tank for a certain angle; the collecting tank is arranged at the rear part of the fine filtering layer; the collecting tank comprises a comb and a tank body; the fine filtering layer comprises a water distributor and a fine filtering net; the water distributor is arranged in front of the fine filtering net; a deversoir is arranged at the tail end of the water distributor. In the working process, relatively large dirt impurities in sewage can be baffled by the coarse screen, and relatively small dirt impurities are baffled by the fine filtering net, are fed into the collecting tank under the action of hydraulic scouring and gravity, and can be directly dumped. Filtered water drops into the biological activated carbon trickling filter, and dissoluble pollutants are adsorbed and biologically degraded. The coarse screen and the fine filtering layer do not need power for cleaning of filtering nets, and the biological activated carbon trickling filter does not need power for aeration, either. By adopting the powerless sewage purification device, the purpose of removing suspended pollutants and dissoluble pollutants in sewage without power can be achieved.

The invention discloses a device and method for realizing autotrophic nitrogen removal and synchronous phosphorus recovery of domestic sewage by using granular sludge with hydroxyapatite as a crystal nucleus, and belongs to the field of sewage treatment. The device comprises a short-cut denitrification coupling anaerobic ammonia oxidation reactor and a side granular sludge treatment reactor. CaCl2 and phosphate are added into the side treatment reactor, hydroxyapatite is formed to promote conversion of anaerobic ammonia oxidation sludge from floc to granular sludge, and after culture for a certain period of time, the sludge is obviously granulated, so that the settling performance of the sludge is improved, retention and high enrichment of anaerobic ammonia oxidation bacteria are facilitated, and therefore, the denitrification contribution rate is improved, and the energy consumption is reduced. Meanwhile, the content of phosphate in the sludge is increased to 20% or above, and recycling of important resource phosphorus can be achieved through regular sludge discharging.

The invention provides a composite material for accelerating formation of aerobic granular sludge as well as a preparation method and application of the composite material. According to the invention, an aerobic granular sludge rapid construction system based on the porous carbon and iron-based material composite nanomaterial is constructed, and the porous carbon and the iron-based material are added to prepare the composite nanomaterial, so that the forming speed of the aerobic granular sludge is remarkably increased; compared with the composite nano material which is added with an inert material and is not added with the material, the time of the composite nano material prepared by the invention is shortened by 30-50%. The prepared aerobic granular sludge is good in stability after being mature and can resist large impact loads, the quality of treated sewage reaches the first-grade A standard, the treatment capacity on conventional pollutants is improved by 10%-30%, and compared with a conventional aerobic granular sludge technology, the aeration rate and occupied land are saved, and energy consumption is reduced by 10%-30%.

The invention discloses a device for recycling, filtering and utilizing the wastewater of a large fish tank. The device comprises a body and is characterized in that a fishing cavity is arranged in the body, a hollow pipe is fixedly arranged on the left side of the body, a water inlet pipeline is communicated between the hollow pipe and the fishing cavity, a collecting device for collecting garbage such as duckweeds and water plants is arranged in the fishing cavity, and the wastewater is pumped into the fishing cavity through the water inlet pipeline. The device has the advantages that automatic water changing, water plant cleaning, manure cleaning, water filtering and the like can be performed on the large fish tank; compared with traditional simple physical and chemical filtering, the device can collect and separate the water plants falling from the fish tank first to prevent the fallen water plants from affecting the attractiveness of the fish tank and can independently collect sludge and manure and directly separate the sludge and the manure from the wastewater to reduce the contact time of manure and water so as to reduce the generation of ammonia and nitrite.

The invention provides a novel diversion enhanced oxygen dissolving and mass transferring sewage processing tower. The tower comprises a tower body with an opened upper end. A diversion grid and a perforated fixing plate divide the tower body into a water distribution and mud distribution area, a contact oxidation area, a sludge backflow area and a sewage backflow area. The tower is characterized in that a mud distribution plate and a water distributor are arranged above the diversion grid; a vertical contact grid is arranged in the contact oxidation area; the peripheries of the upper parts of the sludge backflow area and the sewage backflow area are both provided with a vent hole; and the air flow between the vent holes and the opening in the upper end of the tower body is used to aerate the sludge and sewage in the contact grid. Sewage flows along the contact grid at a certain flowing speed, the aerobic sludge growing on the contact grid is fully contacted with the sewage; the flowing speed is larger, the mass transferring efficiency is better; and the sewage is purified by repeatedly refluxing the sewage. The aeration on sludge and sewage by a blower fan is not needed, the operation cost is reduced, at the same time, the height / diameter ratio of the tower is large, and the occupied area of an aerobic column is also saved.

The invention discloses a garbage transfer station leachate treatment integrated device, which comprises a pretreatment unit, a biochemical treatment unit and a sludge treatment unit, the pretreatment unit comprises an adjusting tank, a reaction tank and an air floatation tank, the outlet of the adjusting tank is connected with the inlet of the reaction tank, and the outlet of the reaction tank is connected with the inlet of the air floatation tank; the biochemical treatment unit comprises an MABR tank, an MBBR tank and an MBR tank, an outlet of the floatation tank is connected with an inlet of the MABR tank, an outlet of the MABR tank is connected with an inlet of the MBBR tank, an outlet of the MBBR tank is connected with the MBR tank, and a first outlet of the MBR tank is connected with an inlet of the MABR tank; the sludge treatment unit comprises a sludge thickening tank and a sludge dewatering machine. The invention further discloses a garbage transfer station leachate treatment method. According to the method, the MABR, MBBR and MBR combined process is adopted as the method for removing the organic matters, ammonia nitrogen and total nitrogen in the leachate of the waste transfer station, so that the method is safe and efficient; the integrated treatment device disclosed by the invention is high in integration degree, small in occupied area and convenient to mount.

The invention discloses a method for starting short-cut nitrification sludge micro-expansion under the condition of low carbon-nitrogen ratio domestic sewage, and belongs to the technical field of biological sewage treatment. The method includes inoculating short-cut nitrification sludge in the SBR reactor; domesticating for 7 days to recover the activity, wherein the SVI is 60-80ml / g; starting short-cut nitrification sludge micro-expansion: performing continuous aeration in the first-stage single-cycle operation mode with low dissolved oxygen (DO concentration is 0.5 + / -0.1 mg / L), the aerobic time being 150-210 min, finishing aeration at the ammonia valley point, namely dissolved oxygen suddenly rises, enabling the nitrite accumulation rate to be larger than 85% after operation for 25 days and be kept stable, and entering the second stage; performing intermittent aeration in the second state, performing single-period oxygen deficiency and aerobic alternate operation for three times,wherein the ratio of oxygen deficiency to aerobic is 30: 60 min, stably keeping the short cut nitrification sludge micro-expansion state after operation is performed for 30 days, and controlling SVI to be 180-230 ml / g. Under the condition of low dissolved oxygen, low-carbon-nitrogen-ratio domestic sewage serves as inlet water, short-cut nitrification sludge micro-expansion can be started and stably maintained, the total nitrogen and COD removal rate of outlet water is increased, the water quality of the outlet water is improved, and the aeration rate and a carbon source are saved.

The invention discloses a short-range nitrification / denitrification dephosphorization-series device and method for synchronously recovering phosphorus. The device comprises a municipal sewage raw water tank, a short-range nitrification reactor, a phosphorus recovery water tank, a denitrification dephosphorization / phosphorus recovery reactor and a dosing tank. The method comprises the following steps: municipal sewage enters the short-range nitrification reactor to perform denitrification and short-range nitrification; the sewage enters the denitrification dephosphorization / phosphorus recovery reactor to implement synchronous denitrification and dephosphorization, enters an aerobic section to sufficiently absorb phosphorus, and is discharged after reaching the standard; a certain volume of carbon source in the dosing tank enters the denitrification dephosphorization / phosphorus recovery reactor; microbes ingest the provided carbon source to store PHA and release abundant phosphorus; and a certain volume of treated water containing abundant phosphorus is recovered as a high-concentration phosphorus solution. The method can implement synchronous denitrification dephosphorization and phosphorus recovery, treats the sewage and recovers the resources.

According to the method for synchronously removing nitrogen and carbon from swine wastewater, denitrification, methanation, short-cut nitrification and anaerobic ammonia oxidation are organically combined through an EGSB-SMD and EGSB-PNA two-stage reactor, the advantages of functional bacteria in the reactor are improved to the maximum extent through the two-stage SMD-PNA system, ammonia nitrogen and organic carbon are almost completely removed, culture is easy, and the method is suitable for industrial production. The whole process is high in stability and controllability. In the EGSB-SMD, the anoxic-anaerobic structure of the granular sludge is beneficial to the synergetic symbiosis of methanogens and denitrifying bacteria, the COD removal load is higher while the removal of NO2-N and NO3-N in raw water and reflux sewage is considered, and an internal reflux device and a PNA external reflux device in the SMD dilute the influent concentration and reduce the substrate inhibition. In EGSB-PNA, an internal reflux device increases the ascending velocity and promotes the formation of granular sludge with larger volume, and soft and semi-soft combined filler in the reactor promotes the formation and tight attachment of a biological membrane, so that the biomass in the reactor is maintained, and the stable operation of a CANON process is maintained.

The invention discloses a method for removing trace gasoline component BTEX in groundwater with high efficiency and low energy consumption. Sludge supernatant goes through activated carbon bed layer from bottom to top through a sampling pump, flows back a sludge supernatant storage tank after flowing out from the upper end of an activated carbon column and so the cyclic inoculation goes; inlet water is switched into BTEX polluted water to carry out acclimation reproduction on bacteria inoculated on the activated carbon so as to form a biofilm; the inlet water enters the activated carbon column through the sampling pump by an updraft mode, and after operation the biofilm becomes mature through natural acclimation at the BTEX activated carbon column; after the biological activated carbon bed layer is slightly dredged, part microorganism in the bed layer goes up to the upper part of the bed layer with the rise of the water flow, trace microorganism concentrated bacteria liquid is removed by a pipette and is taken as a bacteria source after being diluted; and the bacteria source is used for inoculation of new carbon columns by the previous cyclic inoculation method, thus obtaining new BTEX biological activated carbon technique. The method has the advantages of high capacity load, small requirement amount on dissolved oxygen, simple and convenient flow, simple technique equipment and easy operation and management.

The invention discloses a coal-fired boiler flue gas decarburization device, and relates to the technical field of coal-fired boiler decarburization. The coal-fired boiler flue gas decarburization device comprises a convection rotation decarburization device and a preheating calcination system; and the convection rotation decarburization device comprises a decarburization bin fixedly arranged at the top end of a boiler body and four partition plates, wherein the decarburization bin is in clearance fit with the four partition plates to form a filter cavity, an adsorption cavity, a first reaction cavity, a second reaction cavity and a pressure discharge cavity. Carbon in the boiler is treated by arranging the preheating calcining system and the convection rotating decarburization device, the carbon is sufficiently combusted firstly, and then a small amount of carbon monoxide in the carbon is re-calcined, so that the content of the carbon monoxide in the boiler body is reduced; and then when the air pressure of the boiler body is too high, smoke enters the convection rotating decarburization device, and after carbon dust in flue gas is filtered and adsorbed, carbon monoxide reacts and is converted into carbon dioxide, and then the carbon dioxide reacts and is stored, so that carbon is separated in a multi-layer manner.

The invention discloses an urban sewage treatment process for recovering organic matter and phosphorus. The process system includes the main process units such as transfer aggregation, precipitation separation, biofilm and denitrification treatment, as well as hydrothermal treatment and modification preparation. Urban sewage is treated by transfer, aggregation and sedimentation, and the organic matter is concentrated and enriched in the sludge to be removed, and then enters the biofilm unit, absorbs and removes phosphorus through aerobic operation, and then undergoes biological denitrification treatment, and finally the effluent meets the discharge requirements. Part of the sludge is subjected to hydrothermal treatment, and the obtained water-soluble macromolecular polymer is modified to prepare a transfer aggregation medium, which is reused in the transfer aggregation process of sewage; Reuse the same recovery solution until the phosphorus in it increases to the limit concentration and then replace it to obtain a high-concentration phosphorus solution; hydrothermal treatment can also obtain the carbon source required for biofilm and biological denitrification. Excess sludge and hydrothermal treatment solid phase products are easy to recycle.

The invention discloses a device and method for treating petrochemical wastewater by microaerobic hydrolysis acidification-A / O biofilm method. In the invention, air is introduced into the hydrolytic acidification tank to control the amount of aeration so that it is in the state of microaerobic hydrolysis acidification. A sedimentation tank is installed at the end of the hydrolytic acidification tank for sludge reflux. The supernatant enters the A / O biofilm reactor, and the O section is filled with porous plastic ball carriers filled with polyurethane foam. The effluent enters the secondary settling tank for mud-water separation, and the sludge returns to Section O, the supernatant was discharged. The method of the present invention treats petrochemical wastewater at normal temperature, does not need to add acid and alkali to adjust the pH value, can effectively inhibit the reduction of sulfate in petrochemical wastewater, and reduce H 2 The generation of S reduces the corrosion of metal equipment. The entire sewage treatment system has high efficiency and reliable operation, and is especially suitable for standard upgrading and transformation of existing petrochemical sewage treatment plants.

The invention discloses a device and a method for a low-C / N ratio municipal wastewater short-cut denitrification / short-cut nitrification anaerobic ammonia oxidation biofilm process, belonging to the field of biological sewage treatment. The method comprises the following steps: allowing municipal wastewater and one part of supernatant subjected to short-cut nitrification anaerobic ammonia oxidation in the previous cycle to simultaneously enter a short-cut denitrification bio-membrane reactor, performing anaerobic stirring, performing short-cut denitrification by fully utilizing a carbon source in raw water, and reducing NO3<-> into NO2<->, so that the influence of organic matters in the raw water on microbes in the subsequent short-cut nitrification anaerobic ammonia oxidation bio-membrane reactor; and pumping the supernatant containing NH4<+> and NO2<-> into the short-cut nitrification anaerobic ammonia oxidation bio-membrane reactor through a peristaltic pump for carrying out an anaerobic ammonia oxidation reaction, performing short-cut nitrification and anaerobic ammonia oxidation on the residual NH4<+> in an intermittent aeration and intermittent stirring manner, and finally draining. According to the method disclosed by the invention, the carbon source does not need to be added, advanced nitrogen removal of the low-C / N ratio municipal wastewater is realized, and the method has the advantages of energy consumption, small treatment amount of residual sludge, and the like.

The invention discloses a low-concentration ammonia nitrogen sewage treatment device and a treatment method. The low-concentration ammonia nitrogen sewage treatment device includes: a water inlet tank, a reactor, and a terminal sedimentation tank; the reactor includes an aerobic zone I and an intermediate sedimentation tank , aerobic zone II, anoxic zone I and anoxic zone II; the ratio of the volume of the aerobic zone II to the sum of the volumes of the anoxic zone I and hypoxia II zone is 15:30-40; the end The sedimentation tank is equipped with a drainage pipe, a sludge return pipe and a second sludge pipe for discharging sludge. The inlet end of the sludge return pipe is connected to the terminal sedimentation tank, and the outlet end is connected to the sludge inlet of the aerobic zone II. connected. The low-concentration ammonia nitrogen sewage treatment device of the present invention not only strengthens the TN removal effect in the aerobic zone and increases the contribution rate of autotrophic denitrification, but also enriches ANAMMOX bacteria in the anoxic zone, thereby constructing an economical, stable and efficient new biological denitrification system . Moreover, the invention can save aeration, save commercial carbon sources, effectively recover energy and save sludge treatment costs.