A decentralized low-carbon wastewater treatment device and method based on anaerobic ammonia oxidation

Abstract

The present invention discloses a decentralized low-carbon sewage treatment device and method based on anaerobic ammonia oxidation, the device includes a sewage inlet tank for receiving external raw water, which can transport the raw water to a UASB reactor and a continuous flow reactor respectively in proportion; the UASB reactor is used to convert organic matter in the raw water into methane; a suspended anaerobic ammonia oxidation bacteria filler is added in the continuous flow reactor, and raw water denitrification is achieved through short-range nitrification / anaerobic ammonia oxidation and short-range denitrification / anaerobic ammonia oxidation, and the hydraulic retention time in the anoxic zone is extended to achieve synchronous in-situ fermentation of sludge, and a check gate is set to solve the problem of sludge back mixing; the secondary sedimentation tank precipitates the raw water after denitrification, and returns part of the sludge to the continuous flow reactor. The present invention does not need to add additional carbon sources, effectively solves the problem of back mixing in the reaction zone, realizes the resource utilization of decentralized sewage organic matter and sludge reduction generated in highway service areas, etc., and has the characteristics of high denitrification efficiency, stable performance and effective reduction of carbon emissions.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage biological treatment, and in particular to a decentralized sewage low-carbon treatment device and method based on anaerobic ammonia oxidation. Background Art

[0002] With the development of my country's social economy, urban and rural water consumption continues to increase, highway service areas and major scenic spots have been developed one after another, and centralized sewage treatment facilities cannot meet the increasing treatment load and decentralized regional sewage treatment needs. Therefore, the use of decentralized sewage treatment technology to treat sewage on a small scale has become an inevitable trend for future development. The decentralized sewage generated by highway service areas, port terminals, scenic spots, rural living areas, etc. is mainly domestic sewage, which is greatly affected by daily traffic and seasonal climate. It has the characteristics of large water quality volatility, high organic pollution concentration, high nitrogen and phosphorus content, especially the ammonia nitrogen concentration in sewage. If it is not discharged up to standard, it will cause serious water oxygen enrichment and oxidation problems. At present, my country's nitrogen emission standards are becoming increasingly stringent. The existing traditional denitrification process has poor treatment effect, high energy consumption, and high operating costs. It is urgent to seek a new sewage denitrification technology with high denitrification efficiency, low energy consumption and stable operating performance. Summary of the invention

[0003] The purpose of the present invention is to provide a decentralized low-carbon sewage treatment device and method based on anaerobic ammonia oxidation to solve the problems existing in the above-mentioned prior art, with high denitrification efficiency, low energy consumption and stable operating performance.

[0004] To achieve the above object, the present invention provides the following solutions:

[0005] The present invention provides a decentralized low-carbon sewage treatment device based on anaerobic ammonia oxidation, comprising a sewage inlet tank, a UASB reactor, an intermediate water tank, a continuous flow reactor, and a secondary sedimentation tank; the sewage inlet tank is used to receive external raw water and transport it to the UASB reactor and the continuous flow reactor respectively in proportion; the UASB reactor is used to convert organic matter in the raw water into methane through anaerobic digestion, 60% of the wastewater first enters the anaerobic digestion reactor, and the anaerobic methanogens convert the organic matter in the inlet water into methane, which is recycled and utilized as a resource, and the effluent enters the anaerobic digestion reactor. Intermediate water tank; the effluent from the intermediate water tank is used to enter the continuous flow reactor, in which suspended anaerobic ammonium oxidizing bacteria fillers are added, and raw water is denitrified through short-range nitrification / anaerobic ammonium oxidation and short-range denitrification / anaerobic ammonium oxidation processes, and the hydraulic retention time in the anoxic zone is extended to achieve synchronous in-situ fermentation of sludge, and a check gate is set to solve the problem of sludge backmixing; the secondary sedimentation tank is provided with an overflow weir, a secondary sedimentation tank outlet, a sludge discharge gate valve, and a sludge return control gate valve. The secondary sedimentation tank is used to precipitate the raw water after denitrification and return part of the sludge to the continuous flow reactor. During operation, sewage enters the UASB reactor and the first anoxic reactor from the water inlet tank through the first water inlet pump and the second water inlet pump respectively. A water outlet is arranged at the upper end of the UASB reactor, which is connected to the intermediate water tank through the intermediate water tank inlet pump and the intermediate water tank inlet pipe, and the intermediate water tank is connected to the first aerobic reactor through the third water inlet pump and the third water inlet pipe; a water outlet is arranged at the end of the continuous flow reactor, which is connected to the second sedimentation tank through the continuous flow reactor outlet pipe, and the effluent is discharged from the system through the outlet after mud and water separation; the sludge part of the second sedimentation tank is controlled by the sludge return control gate valve and the sludge return pump to return to the first aerobic reactor, and the remaining sludge is controlled by the sludge discharge gate valve to discharge the system; the sewage in the continuous flow reactor is discharged through the baffle outlet hole The check valve is set to strictly control the unidirectional flow of water; the aeration volume of the aerobic reactor is controlled by an aeration pump and a gas flow meter, and aeration is carried out through an annular aeration plate, wherein the dissolved oxygen of the first aerobic reactor, the second aerobic reactor and the fourth aerobic reactor is controlled at 0.1-0.3 mg / L, and the dissolved oxygen of the third aerobic reactor and the fifth aerobic reactor is controlled at 2-3 mg / L; the anoxic reactor is equipped with a rigid-flexible combined stirring paddle; suspended spherical corrugated anaerobic ammonia-oxidizing bacteria filler is added into the aerobic reactor and the anoxic reactor. The corrugated filler has a large specific surface area and is easy for anaerobic ammonia-oxidizing bacteria to attach. Polypropylene filler with a diameter of (20-30)±2 mm is used, and the filling ratio is 25%-30%.

[0006] Optionally, the sewage inlet tank is provided with an outlet pipe, and the outlet pipe is respectively connected to a first inlet pipe and a second inlet pipe, the first inlet pipe is provided with a first inlet pump, and the end of the first inlet pipe is connected to the bottom of the UASB reactor; the second inlet pipe is provided with a second inlet pump, and the end of the second inlet pipe is connected to the first anoxic reactor of the continuous flow reactor.

[0007] Optionally, a multi-stage three-phase separator is provided in the UASB reactor, a gas collecting port is provided on the top of the multi-stage three-phase separator, a plurality of sampling ports are provided on the lower side of the UASB reactor, an emptying valve is provided at the emptying port at the bottom of the UASB reactor, a water outlet is provided on the upper side of the UASB reactor, and the water outlet is connected to the intermediate water tank through the intermediate water tank inlet pump and the intermediate water tank inlet pipe; the water inlet at the bottom of the UASB reactor is connected to the sewage inlet tank; the internal reflux port above the UASB reactor is connected to the water inlet at the bottom of the UASB reactor through the internal reflux pump.

[0008] Optionally, the multi-stage three-phase separator includes a sludge settling inclined plate, an air collecting hood, an air collecting plate, an air collecting pipe and an air collecting chamber; a plurality of triangular air collecting hoods are provided above the symmetrically arranged sludge settling inclined plates, the air collecting hoods are connected to the air collecting plates, the top of the air collecting plates is connected to the air collecting pipe, the top of the air collecting pipe is connected to the air collecting chamber, and the top of the air collecting chamber is connected to the air collecting port.

[0009] Optionally, the continuous flow reactor includes a first aerobic reactor, a second aerobic reactor, a third aerobic reactor, a first anoxic reactor, a second anoxic reactor, a third anoxic reactor, a fourth anoxic reactor, a fourth aerobic reactor and a fifth aerobic reactor which are sequentially arranged from left to right through a partition, a water outlet hole is opened on the partition, a check door is hinged on the right side of the water outlet hole, the first aerobic reactor is connected to the water outlet of the intermediate water tank through a third water inlet pump and a third water inlet pipe; the first aerobic reactor, the second aerobic reactor, the third aerobic reactor, the fourth aerobic reactor and the fifth aerobic reactor are respectively provided with annular aeration disks at the bottom, and a plurality of the annular Aeration plates are connected to aeration pumps through pipelines, and a gas flowmeter is provided on the pipelines connecting the annular aeration plates and the aeration pumps; the first anoxic reactor, the second anoxic reactor, the third anoxic reactor and the fourth anoxic reactor are respectively provided with rigid-flexible combination stirring paddles, and the first aerobic reactor, the second aerobic reactor, the first anoxic reactor, the second anoxic reactor, the third anoxic reactor, the fourth anoxic reactor and the fourth aerobic reactor are all provided with suspended spherical corrugated anaerobic ammonia-oxidizing bacteria fillers; the fifth aerobic reactor is connected with the second sedimentation tank through a continuous flow reactor outlet pipe, and the sludge outlet at the bottom of the second sedimentation tank is connected with the first aerobic reactor through a sludge return pump and a sludge return pipe.

[0010] Optionally, the suspended spherical corrugated anaerobic ammonia oxidizing bacteria filler has an appearance of a regular spherical corrugated structure with a plurality of small pores distributed on the surface, and the surface and pores of the suspended spherical corrugated anaerobic ammonia oxidizing bacteria filler are enriched with anaerobic ammonia oxidizing bacteria.

[0011] Optionally, the rigid-flexible combination stirring paddle includes a stirring paddle shaft, a flexible curved stirring plate and a rigid straight stirring plate. The rigid-flexible combination stirring paddle has six identical rigid straight stirring plates equidistantly arranged on the upper and lower layers, and six identical flexible curved stirring plates arranged on the middle layer. Both ends of the flexible curved stirring plates are staggeredly connected to the rigid straight stirring plates on the upper and lower layers to maximize the surface curvature.

[0012] Optionally, the check gate is a circular baffle structure, the upper end of which is connected to the partition via a rotating shaft, and the check gate can rotate freely; a hollow circle with a diameter smaller than the check gate is arranged on the side of the partition in the opposite direction of the water flow, thereby forming a check gate slot to prevent the check gate from rotating in the opposite direction.

[0013] Optionally, the annular aeration plate includes an air inlet pipe, aeration pipes of different diameters and aeration holes. A plurality of aeration holes are evenly distributed on the aeration pipe, and the hole diameters thereof are proportional to the diameter of the annular aeration plate. Gas enters the air inlet pipe and is discharged into the water body through the aeration holes on the aeration pipe, showing the characteristics of large outer bubble diameter and large inner bubble density and small diameter.

[0014] The present invention also provides a decentralized low-carbon sewage treatment method based on anaerobic ammonia oxidation, which utilizes anaerobic methanogens to remove most of the organic matter, and after separation through a multi-stage three-phase separator, enters the front aerobic zone of a continuous flow device through an intermediate water tank; the remaining 40% of the sewage enters the continuous flow anoxic zone; short-range nitrification / anaerobic ammonia oxidation and short-range denitrification / anaerobic ammonia oxidation denitrification are realized in the continuous flow device; wherein, short-range nitrification / anaerobic ammonia oxidation denitrification is realized by removing organic matter from raw water, controlling the aeration volume, and adding suspended anaerobic ammonia oxidation bacteria fillers in the aerobic zone; short-range denitrification / anaerobic ammonia oxidation denitrification is realized by providing ammonia nitrogen and organic matter through staged water inlet, extending the hydraulic retention time to realize simultaneous in-situ fermentation of sludge to provide a carbon source, fully stirring, and setting a check gate to prevent back mixing; an aerobic zone is set at the end of the continuous flow reactor, and the ammonia nitrogen released in the in-situ fermentation process of the sludge is further removed by the added anaerobic ammonia oxidation bacteria fillers to ensure that the effluent ammonia nitrogen meets the standards. This system can solve the problem of back-mixing in the reaction zone and provide favorable conditions for anaerobic ammonia-oxidizing bacteria to denitrify. No additional carbon source is required during the operation process. The carbon source produced by in-situ fermentation of sludge can easily achieve stable accumulation of nitrite nitrogen and achieve the effect of sludge reduction. At the same time, the organic matter in the sewage is pre-recovered to produce methane, promoting the decentralized resource utilization of sewage. The specific steps include the following:

[0015] 1) Inoculate the return sludge from the secondary sedimentation tank of the service area sewage treatment process, add it to the UASB reactor and the continuous flow reactor, and cultivate the sludge to the set concentration, so that the sludge concentration reaches 3000-4000 mg / L, and then add anaerobic ammonia-oxidizing bacteria filler to the aerobic reactor and the anoxic reactor, and the filling ratio is 25%-30%;

[0016] 2) The average hydraulic retention time in the UASB reactor and the continuous flow reactor is set respectively. The average hydraulic retention time of the UASB reactor is 3-4h, and the average hydraulic retention time HRT of the continuous flow reactor is controlled at 20-23h. In order to achieve synchronous in-situ sludge fermentation, the hydraulic retention time HRT of the anoxic reactor is controlled at 12-15h; the discharge of the excess sludge is controlled by the sludge discharge valve, and the sludge age of the flocculent sludge in the reactor is controlled at the set time, and the sludge age of the flocculent sludge in the reactor is controlled at 14-16d;

[0017] 3) The sewage in the sewage inlet tank enters the continuous flow reactor in sections, of which 60% of the wastewater enters the UASB reactor and 40% of the wastewater enters the first anoxic reactor; the effluent of the UASB reactor enters the intermediate water tank and enters the first aerobic reactor through the third water inlet pump; the first aerobic reactor controls the aeration volume through a gas flow meter, and provides trace oxygen through the annular aeration disk to convert part of the ammonia nitrogen in the raw water into nitrite nitrogen. The anaerobic ammonia oxidizing bacteria attached to the suspended spherical corrugated anaerobic ammonia oxidizing bacteria filler utilizes nitrite nitrogen and ammonia nitrogen in the raw water to generate nitrogen and nitrate nitrogen; then it enters the third aerobic reactor, and a large amount of oxygen is provided by the aeration pump to convert all the ammonia nitrogen in the effluent of the second aerobic reactor into nitrate nitrogen; the third The effluent from the aerobic reactor and 40% of the raw water enter the first anoxic reactor at the same time. Under the stirring of the rigid-flexible combination stirring paddle, the anaerobic ammonia-oxidizing bacteria use the organic matter produced by the in-situ fermentation of the sludge and the organic matter in the raw water to convert the nitrate nitrogen in the effluent of the third aerobic reactor into nitrite nitrogen, which then reacts with the ammonia nitrogen in 40% of the raw water to generate nitrogen and nitrate nitrogen; subsequently, the effluent from the fourth anoxic reactor enters the fourth aerobic reactor. Under the condition of micro-aeration, part of the ammonia nitrogen is oxidized into nitrite nitrogen. The anaerobic ammonia-oxidizing bacteria use the nitrite nitrogen and the remaining ammonia nitrogen in the water to further convert them into nitrogen and nitrate nitrogen, and finally enter the fifth aerobic reactor. The nitrifying bacteria oxidize the remaining ammonia nitrogen in the water under sufficient aeration, and the effluent that meets the ammonia nitrogen standard enters the secondary sedimentation tank;

[0018] 4) Part of the sludge from the secondary sedimentation tank is returned to the first aerobic reactor through the sludge return pump, and the sludge return ratio is controlled to be 50%. The remaining sludge is discharged from the system through the sludge discharge gate valve.

[0019] Compared with the prior art, the present invention has achieved the following technical effects:

[0020] The process of the present invention is simple to operate and convenient to run and manage, and is suitable for application in scenarios such as highway service areas and scenic spots that are located in remote areas and have limited staff.

[0021] 1) The UASB reactor unit of the present invention and the nine unit cells of the continuous flow reactor together form a complete denitrification process chain. The units are interconnected and cooperate with each other. No external carbon source is required. By controlling the aeration volume and hydraulic retention time, the short-range nitrification / short-range denitrification coupled anaerobic ammonia oxidation system is achieved to achieve efficient and low-carbon treatment of decentralized sewage, thereby maximizing resource utilization;

[0022] 2) The staged water inlet can make full use of organic matter in the water. Part of it is converted into methane for resource recycling, and the rest provides a carbon source for the short-range denitrification process. The methane gas recovery adopts a multi-stage three-phase separator for decentralized collection, which is conducive to improving the gas collection efficiency and reducing the gas collection pressure of a single three-phase separator;

[0023] 3) The simultaneous in-situ fermentation of sludge in the anoxic zone provides an easily available organic carbon source, promotes the stable accumulation of nitrite nitrogen in the denitrification process, reduces the cost of carbon source addition, and is conducive to sludge reduction;

[0024] 4) The determination of HRT in the anoxic zone is the key to achieving in-situ fermentation and acid production of sludge. The anaerobic fermentation process of sludge takes a long time, and the hydrolysis stage is the main rate-controlling step, which decomposes complex high-molecular organic matter into small-molecular organic matter, and then enters the acidification stage, which is converted into easily usable volatile fatty acids and other organic matter; in order to enrich a certain amount of volatile acids, the optimal fermentation time was optimized through a large number of comparative tests, and finally the HRT of the anoxic zone was controlled at 12-15h, which promoted the accumulation of nitrite by short-term denitrification and further realized anaerobic ammonia oxidation denitrification, which has certain creativity in the field of decentralized sewage treatment;

[0025] 5) Before the wastewater enters the aerobic zone, organic matter is removed in advance to reduce the impact of heterotrophic bacteria and organic matter on anaerobic ammonia-oxidizing bacteria, which is conducive to the enrichment of anaerobic ammonia-oxidizing bacteria; anaerobic ammonia-oxidizing bacteria fillers are added to the micro-aeration reactor in the aerobic zone, and the aeration volume is strictly controlled to achieve short-range nitrification coupled with anaerobic ammonia oxidation denitrification, which can greatly reduce the aeration volume, reduce operating costs, and reduce sludge production. The anaerobic ammonia-oxidizing bacteria filler adopts a spherical corrugated design, which greatly increases the specific surface area and is densely covered with gaps, which is conducive to the enrichment and growth of anaerobic ammonia-oxidizing bacteria;

[0026] 6) Each continuous flow reactor is isolated by a partition, and a check valve is set at the water outlet. When the water flows forward, the check valve is opened, and when the water flows reversely, the check valve is closed, which can guide the water to flow in one direction to prevent the problem of back mixing, forming a microenvironment that is beneficial to nitrifying bacteria, denitrifying bacteria and anaerobic ammonia oxidizing bacteria, meeting the appropriate survival needs of denitrifying strains, facilitating the enrichment of anaerobic ammonia oxidizing bacteria, and improving denitrification efficiency;

[0027] 7) A rigid-flexible combined stirring paddle is set in the anoxic zone. The flexible baffles arranged alternately between the upper and lower blades shake irregularly to form a spiral vortex, which strengthens the fluid mixing performance between the upper and lower layers of blades and effectively solves the problem of long-term sludge accumulation in the "dead corners" of the reactor;

[0028] 8) An annular aeration disk is set in the aerobic zone. The large bubbles in the outer ring and the small bubbles in the inner ring form a spatial pressure difference, which realizes the continuous circulation disturbance of muddy water and suspended fillers in a large range and improves the reaction efficiency;

[0029] 9) The reactor inoculation sludge concentration is determined to be 3000-4000 mg / L, and the anaerobic ammonia-oxidizing bacteria filler filling ratio is determined to be 25%-30%. Through a large number of small-scale comparative tests with different sludge concentrations, it is known that too high sludge or filler concentration will affect the mixing effect, reduce the contact area between bacteria and pollutants, reduce the reaction efficiency, and cause sludge lysis. If the concentration is too low, the bacteria amount is insufficient, resulting in poor effluent effect. Therefore, the determination of this parameter has strong operability. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0031] Figure 1 It is a schematic diagram of a decentralized low-carbon sewage treatment device based on anaerobic ammonia oxidation according to the present invention;

[0032] Figure 2 It is a schematic diagram of the structure of the multi-stage three-phase separator in the UASB reactor;

[0033] Figure 3 This is a schematic diagram of the three-dimensional structure of the check door;

[0034] Figure 4 It is a schematic diagram of the structure of an annular aeration disk;

[0035] Figure 5 This is a schematic diagram of the rigid-flexible combined stirring paddle structure;

[0036] Figure 6 This is a schematic diagram of the side structure of the check door;

[0037] Among them, 1-sewage inlet tank, 11-outlet pipe; 2-UASB reactor, 21-first inlet pump, 22-first inlet pipe, 23-multi-stage three-phase separator, 24-gas collecting port, 25-sampling port, 26-drain valve, 27-outlet, 28-internal reflux pump; 3-intermediate water tank, 31-intermediate water tank inlet pump, 32-intermediate water tank inlet pipe; 4-continuous flow reactor, 41-second inlet pump, 42-third inlet pump, 43-second inlet pipe, 44-third inlet pipe, 451-first aerobic reactor, 452-second aerobic reactor, 453-third aerobic reactor, 454-fourth aerobic reactor, 455-fifth aerobic reactor, 461-first anoxic reactor, 462-second anoxic reactor, 463-third anoxic reactor, 464-third Four anoxic reactors, 47-annular aeration disc, 48-aeration pump, 49-gas flow meter, 410-rigid-flexible combination stirring paddle, 411-partition, 412-check gate, 413-suspended ball-shaped corrugated anaerobic ammonia-oxidizing bacteria filler, 414-continuous flow reactor outlet pipe, 415-sludge return pump, 416-sludge return pipe; 5-secondary sedimentation tank, 51-overflow weir, 52-secondary sedimentation tank outlet Mouth, 53-sludge discharge gate valve, 54-sludge return control gate valve, 231-sludge settling inclined plate, 232-air collecting hood, 233-air collecting plate, 234-air collecting pipe, 235-air collecting chamber, 4121-check door slot, 471-aeration hole, 472-air inlet pipe, 473-aeration pipe, 4101-flexible curved plate, 4102-rigid straight plate, 4103-agitator shaft. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] The purpose of the present invention is to provide a decentralized low-carbon sewage treatment device and method based on anaerobic ammonia oxidation to solve the problems existing in the above-mentioned prior art, with high denitrification efficiency, low energy consumption and stable operating performance.

[0040] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Compared with traditional denitrification processes, short-cut nitrification / short-cut denitrification coupled anaerobic ammonium oxidation has the advantages of saving aeration volume and organic carbon source, reducing sludge production and high nitrogen removal load, and therefore has received widespread attention. The stable acquisition of nitrite is a key step in achieving anaerobic ammonium oxidation denitrification. Short-term nitrification, as one of the acquisition methods, can save 60% of aeration volume and 100% of carbon source. However, the short-term nitrification process is greatly affected by the environment. In the presence of organic matter, denitrifying bacteria will compete with anaerobic ammonium oxidizing bacteria for nitrite nitrogen and inhibit the activity of anaerobic ammonium oxidizing bacteria. Therefore, anaerobic fermentation bacteria are needed to remove organic matter in the water in advance to provide a good reaction environment for the short-term nitrification coupled anaerobic ammonium oxidation process. Since the nitrification process and anaerobic ammonium oxidation process will inevitably produce a certain amount of nitrate, which affects the effluent nitrogen concentration, a short-term denitrification coupled anaerobic ammonium oxidation process is used for deep denitrification. Nitrite accumulation in the denitrification process can be achieved by controlling pH, organic matter concentration / nitrate nitrogen concentration and organic matter type. However, the low organic matter concentration in the raw water is not conducive to short-term denitrification and requires additional carbon source addition. At present, a large amount of sludge is produced every year in water plants in my country. The fermentation liquid formed after fermentation contains ammonia nitrogen and easily available organic carbon sources, including acetic acid and other volatile fatty acids, which are conducive to promoting the accumulation of nitrite in the denitrification process. If it is not used reasonably, it will cause a waste of resources. Therefore, the easily degradable organic matter produced by synchronous in-situ fermentation can be used to domesticate short-term denitrifying bacteria, promote sludge reduction, achieve stable nitrite accumulation, and save the cost of adding external carbon sources and sludge disposal costs; the ammonia nitrogen released during the fermentation process can be removed by a subsequent short-term nitrification coupled anaerobic ammonia oxidation reactor, further achieving the effect of low-energy deep denitrification. Based on this, the inventor has uniquely designed a decentralized sewage low-carbon treatment device and method based on anaerobic ammonia oxidation in the present invention.

[0042] Specifically, Figure 1As shown, the sewage inlet tank 1 of the decentralized sewage low-carbon treatment device based on anaerobic ammonia oxidation of the present invention is provided with an outlet pipe 11; the UASB reactor 2 is provided with a first water inlet pump 21, a first water inlet pipe 22, a multi-stage three-phase separator 23, a gas collecting port 24, a sampling port 25, an emptying valve 26, a water outlet 27 and an internal reflux pump 28; the intermediate water tank 3 is provided with an intermediate water tank inlet pump 31 and an intermediate water tank inlet pipe 32; the continuous flow reactor 4 includes a first aerobic reactor 451, a second aerobic reactor 452, a third aerobic reactor 453, a first anoxic reactor 46 1. The second anoxic reactor 462, the third anoxic reactor 463, the fourth anoxic reactor 464, the fourth aerobic reactor 454, and the fifth aerobic reactor 455. The continuous flow reactor 4 is also provided with a second water inlet pump 41, a third water inlet pump 42, a second water inlet pipe 43, a third water inlet pipe 44, an annular aeration plate 47, an aeration pump 48, a gas flow meter 49, a rigid-flexible combination stirring blade 410, a partition 411, a check valve 412, a suspended ball-shaped corrugated anaerobic ammonia-oxidizing bacteria filler 413, a continuous flow reactor outlet pipe 414, and a sludge return pump 415 and sludge return pipe 416; the secondary sedimentation tank 5 is provided with an overflow weir 51, a secondary sedimentation tank outlet 52, a sludge discharge gate valve 53, and a sludge return control gate valve 54; when working, the organic wastewater is removed and enters the short-range nitrification coupled anaerobic ammonia oxidation reactor. Under micro-aerobic conditions, nitrifying bacteria convert part of the ammonia nitrogen in the water into nitrite nitrogen, and anaerobic ammonia oxidizing bacteria use nitrite nitrogen to react with ammonia nitrogen in raw water to generate nitrogen gas to achieve denitrification; the remaining ammonia nitrogen is converted into nitrate nitrogen under sufficient aeration conditions and enters the anoxic zone; the sludge in the anoxic zone is decomposed by fermentation bacteria under long HRT conditions to generate easy-to-use The volatile fatty acids and other organic matter are beneficial to the denitrifying bacteria to convert nitrate nitrogen into nitrite nitrogen. The anaerobic ammonia oxidizing bacteria use the accumulated nitrite nitrogen to react with 40% of the influent ammonia nitrogen to generate nitrogen gas; the effluent enters the short-range nitrification coupled anaerobic ammonia oxidation reactor, and the nitrifying bacteria further convert part of the ammonia nitrogen released in the fermentation process into nitrite nitrogen, which is then used by the anaerobic ammonia oxidizing bacteria to remove nitrogen from the wastewater; then it enters the complete nitrification reactor to convert all the ammonia nitrogen into nitrate nitrogen, ensuring that the ammonia nitrogen concentration in the system effluent meets the standard, and finally realizing the efficient and economical deep denitrification and sludge reduction of decentralized wastewater.

[0043] Further preferably, the specific working process of the present invention is that the sewage enters the UASB reactor 2 and the first anoxic reactor 461 respectively from the sewage inlet tank 1 through the first inlet pump 21 and the second inlet pump 41, and a multi-stage three-phase separator 23 is arranged inside the UASB reactor 2, and the structure is as follows: Figure 2As shown, the biogas collection pressure is dispersed by a multi-stage gas collecting hood 232, and the biogas is collected into a gas collecting chamber 235 through a gas collecting plate 233 and a gas collecting pipe 234. At the same time, the anaerobic flocculent sludge is accurately and effectively intercepted, so that it naturally settles back to the reaction zone along the sludge settling inclined plate 231 with gravity, which can improve the three-phase separation efficiency; the UASB reactor 2 strengthens the internal flocculent sludge fluidization through an internal reflux pump 28, so that the organic matter in the wastewater and the microorganisms are fully contacted and reacted; a water outlet 27 is set at the upper end of the reactor, and the water inlet pump 31 and the intermediate water tank are connected to the reactor. The water tank inlet pipe 32 is connected to the intermediate water tank 3, and the intermediate water tank 3 is connected to the first aerobic reactor 451 through the third water inlet pump 42 and the third water inlet pipe 44; a water outlet is arranged at the end of the continuous flow reactor 4, and is connected to the secondary sedimentation tank 5 through the continuous flow reactor outlet pipe 414, and the effluent is discharged from the system through the secondary sedimentation tank outlet 52 after mud and water separation; the sludge part of the secondary sedimentation tank is controlled by the sludge return control gate valve 54 and the sludge return pump 415 to return to the first aerobic reactor 451, and the remaining sludge is controlled by the sludge discharge gate valve 53 to be discharged from the system.

[0044] like Figure 3 and Figure 6 As shown, the sewage in the continuous flow reactor 4 strictly controls the unidirectional flow of water through the check gate 412 arranged at the water outlet of the partition 411. The door opens along the direction of the water flow. A check gate slot 4121 is arranged to prevent the door from opening in the reverse direction, causing dissolved oxygen to flow into the anoxic zone, consuming organic matter, affecting the denitrification effect, and ensuring the anoxic, anaerobic or aerobic state of each functional zone of the reactor.

[0045] The aeration rate of the aerobic reactor is controlled by an aeration pump 48 and a gas flow meter 49, and aeration is carried out through an annular aeration plate 47. Figure 4 As shown, the gas enters the aeration pipe 473 through the air inlet pipe 472 and is discharged through the aeration holes 471 thereon. The aeration holes 471 are distributed in a ring shape, which effectively solves the problem of uneven mixing of mud and water and enhances the denitrification effect; wherein the dissolved oxygen in the first aerobic reactor 451, the second aerobic reactor 452 and the fourth aerobic reactor 454 is controlled at 0.1-0.3 mg / L, and the dissolved oxygen in the third aerobic reactor 453 and the fifth aerobic reactor 455 is controlled at 2-3 mg / L; Figure 5As shown, the anoxic reactor is equipped with a rigid-flexible combination stirring paddle 410, which includes a stirring paddle shaft 4103, and adopts a design form combining rigid and flexible lines. The flexible curved panel 4101 disturbs the water in the middle area of ​​the reactor at multiple angles and the rigid straight panel 4102 disturbs the water laterally, so that the turbulence intensity in each area is uniform. The flexible baffles staggered between the upper and lower blades shake irregularly to form a spiral vortex, which strengthens the fluid mixing performance between the upper and lower layers of blades, promotes close contact and reaction between nitrogen pollutants and microorganisms, and realizes nitrogen removal. Suspended spherical corrugated anaerobic ammonia oxidizing bacteria filler 413 is added into the aerobic reactor and the anoxic reactor. The corrugated filler has a large specific surface area and is easy for anaerobic ammonia oxidizing bacteria to attach. Polypropylene fillers with a diameter of (20-30)±2mm are used, and the filling ratio is 25%-30%.

[0046] Embodiment 1

[0047] Domestic sewage generated in a certain rural area is deeply treated by combining an anaerobic methanogenic UASB reactor 2 and an O / A / O continuous flow reactor. After being treated in a grit chamber, 60% of the wastewater enters the anaerobic methanogenic UASB reactor 2, where it fully contacts and reacts with the microorganisms in the reactor. The generated methane gas rises with the mud-water mixture to the multi-stage three-phase separator 23, which is equipped with multiple gas collecting hoods 232 to effectively disperse the three-phase separation pressure. The methane gas flows along the gas collecting hood 232 into the gas collecting plate 233, and further enters the gas collecting chamber 235 through the gas collecting pipe 234, and is efficiently recycled. At the same time, the sludge particles are intercepted layer by layer by the gas collecting hood 232 and settle to the sludge settling inclined plate 231 by gravity, and then slide down and return to the reaction area; the wastewater enters the intermediate water tank 3 after the mud and water separation in the sedimentation area of ​​the UASB reactor 2;

[0048] Wastewater from the intermediate water tank 3 enters the aerobic zone of the continuous flow reactor 4, and oxygen enters the reactor through the annular aeration pump 413. Since the diameter of the annular aeration pipe 473 is proportional to the size of the aeration holes 471 thereon, the reactor presents the characteristics of large bubbles on the periphery and small bubbles in the center, forming a pressure difference, effectively increasing the mixing effect of muddy water and fillers, and facilitating short-range nitrification; the external corrugated shape of the suspended spherical corrugated anaerobic ammonia-oxidizing bacteria filler 413 in the aerobic zone increases the specific surface area, promoting its full contact with the wastewater, and the polypropylene material makes its surface have multiple gaps, which is conducive to the attachment and growth of anaerobic ammonia-oxidizing bacteria, and the removal of nitrogen is achieved by utilizing the generated nitrite and ammonia nitrogen in the wastewater;

[0049] The effluent from the aerobic zone enters the anoxic zone simultaneously with the effluent from the 40% grit chamber through the check valve 410. The check valve 410 is opened by the power of the forward water flow and is closed when the reverse water flow passes through, which effectively solves the back-mixing problem and provides independent living conditions for different microorganisms in the aerobic zone and the anoxic zone, ensuring that the anaerobic ammonia oxidizing bacteria can achieve the best denitrification efficiency under a strict anoxic environment. The longer hydraulic retention time in the anoxic zone promotes the decomposition of part of the sludge to generate easily usable organic matter, promotes short-range denitrification, and provides sufficient substrate nitrite for the anaerobic ammonia oxidizing bacteria. A rigid-flexible combined stirring paddle 410 is arranged in the anoxic zone, and the flexible curved stirring plate 4101 staggeredly connected to the rigid straight stirring plate 4102 rotates with the stirring paddle shaft 4103, impacting the wastewater at multiple angles, so that the sludge suspended matter and filler are fully mixed, thereby maximizing the nitrogen removal effect.

[0050] The effluent from the anoxic zone enters the aerobic zone, and the ammonia nitrogen produced by fermentation is further removed through the anaerobic ammonium oxidation process or the nitrification process. The effluent from the aerobic zone enters the secondary sedimentation tank 5 and is discharged from the system after sedimentation.

[0051] Rural wastewater enters the system, and through organic matter removal, short-range nitrification / short-range denitrification coupled anaerobic ammonia oxidation denitrification, the concentration of organic matter and nitrogen in the effluent can be greatly reduced, achieving efficient and stable denitrification while also achieving the effect of sludge reduction.

[0052] Embodiment 2

[0053] The specific test water uses the effluent from the sedimentation tank of a decentralized sewage treatment process in a service area as the raw water. The specific water quality is as follows: COD concentration is 110-800mg / L, TN concentration is 20-210mg / L, NH 3- The nitrogen concentration is 12-150 mg / L, and the experimental sludge is the return sludge of the secondary sedimentation tank of the service area sewage treatment process. Figure 1 As shown, each reactor is supported by organic glass, the effective volume of the anaerobic methanogenic UASB reactor 2 is 20L, the effective volume of the continuous flow reactor 4 is 45.9L, there are 9 cells in total, each cell is 5.1L, the anoxic zone occupies 4 cells, the aerobic zone occupies 6 cells, and the effective volume of the sedimentation tank is 14.9L. A method for decentralized sewage treatment using the above device is carried out according to the following process:

[0054] 1) Inoculate the return sludge from the secondary sedimentation tank of the service area sewage treatment process, add it to the UASB reactor 2 and the continuous flow reactor 4, and cultivate it to make the sludge concentration reach 3000-4000 mg / L; the average hydraulic retention time of the UASB reactor 2 is 3-4h, and the average hydraulic retention time HRT of the continuous flow reactor 4 is controlled at 20-23h, the sludge return ratio is controlled to 100%, and the sludge age SRT is 14-16d;

[0055] 2) The proportions of the raw water entering the UASB reactor 2 and the first anoxic reactor 461 are 60% and 40% respectively; the gas flow meter 49 is adjusted to control the oxygen supply, and the dissolved oxygen in the first aerobic reactor, the second aerobic reactor and the fourth aerobic reactor is maintained at 0.1-0.3 mg / L, and the dissolved oxygen in the third aerobic reactor and the fifth aerobic reactor is maintained at 2-3 mg / L; a rigid-flexible combination stirring paddle is set in the anoxic reactor to ensure that the activated sludge and the sewage are fully contacted and mixed;

[0056] 3) During operation, the HRT of the anoxic zone is continuously adjusted according to the ratio of organic matter to nitrate nitrogen concentration in the anoxic reactor, and the ratio of segmented water inlet is continuously adjusted according to the ratio of ammonia nitrogen to nitrite nitrogen in the inlet water of the first anoxic reactor 461, so that the ratio is close to 1:1.32; after the operation is stable, when the concentration of nitrite nitrogen in the aerobic reactor and the anoxic reactor of the system is greater than 1 mg / L and the ratio of organic matter to nitrate nitrogen in the anoxic reactor reaches 2.5 mg / L, anaerobic ammonia oxidizing bacteria filler 413 is added to the first aerobic reactor, the second aerobic reactor, the fourth aerobic reactor and the anoxic reactor, and the filling ratio is 25%-30%, and the anaerobic ammonia oxidizing denitrification continuous operation state is entered.

[0057] The test results show that after stable operation, the system effluent COD concentration is 30-59 mg / L, TN concentration is 2.5-10 mg / L, NH 3- The N concentration is 0-5 mg / L, which is conducive to achieving deep denitrification of wastewater in the service area. At the same time, the process is simple to operate and easy to manage, and is suitable for decentralized sewage treatment in remote areas.

[0058] In the description of the present invention, it should be noted that the terms "center", "top", "bottom", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0059] The present invention uses specific examples to illustrate the principles and implementation methods of the present invention. The above examples are only used to help understand the method and core ideas of the present invention. At the same time, for those skilled in the art, according to the ideas of the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A decentralized low-carbon sewage treatment device based on anaerobic ammonium oxidation, characterized in that: It includes a sewage inlet tank, a UASB reactor, an intermediate water tank, a continuous flow reactor, and a secondary sedimentation tank; the sewage inlet tank is used to receive external raw water and transport it to the UASB reactor and the continuous flow reactor respectively in proportion; the UASB reactor is used to convert organic matter in the raw water into methane through anaerobic digestion, and its effluent enters the intermediate water tank; the effluent of the intermediate water tank enters the continuous flow reactor, and the continuous flow reactor denitrifies the raw water through short-range nitrification / anaerobic ammonium oxidation and short-range denitrification / anaerobic ammonium oxidation processes; the secondary sedimentation tank is used to precipitate the denitrified raw water and return part of the sludge to the continuous flow reactor; the sewage inlet tank is provided with an outlet pipe, and the outlet pipe is connected to the first inlet pipe and A second water inlet pipe, wherein the first water inlet pipe is provided with a first water inlet pump, and the end of the first water inlet pipe is connected to the bottom of the UASB reactor; the second water inlet pipe is provided with a second water inlet pump, and the end of the second water inlet pipe is connected to the first anoxic reactor of the continuous flow reactor; a multi-stage three-phase separator is provided in the UASB reactor, a gas collecting port is provided on the top of the multi-stage three-phase separator, a plurality of sampling ports are provided on one side below the UASB reactor, an emptying valve is provided at the emptying port at the bottom of the UASB reactor, a water outlet is provided on one side above the UASB reactor, and the water outlet is connected to the intermediate water tank through the intermediate water tank inlet pump and the intermediate water tank inlet pipe; the water inlet at the bottom of the UASB reactor is connected to the sewage inlet tank; The internal reflux port above the UASB reactor is connected to the water inlet at the bottom of the UASB reactor through an internal reflux pump; the continuous flow reactor comprises a first aerobic reactor, a second aerobic reactor, a third aerobic reactor, a first anoxic reactor, a second anoxic reactor, a third anoxic reactor, a fourth anoxic reactor, a fourth aerobic reactor and a fifth aerobic reactor which are sequentially arranged from left to right through a partition, a water outlet hole is opened on the partition, a check door is hinged on the right side of the water outlet hole, the first aerobic reactor is connected to the water outlet of the intermediate water tank through a third water inlet pump and a third water inlet pipe; the inner bottoms of the first aerobic reactor, the second aerobic reactor, the third aerobic reactor, the fourth aerobic reactor and the fifth aerobic reactor are spaced from each other. Each of the first anoxic reactor, the second anoxic reactor, the third anoxic reactor and the fourth anoxic reactor are respectively provided with an annular aeration disk, and the plurality of annular aeration disks are respectively connected to an aeration pump through pipelines, and a gas flow meter is provided on the pipelines connecting the annular aeration disk and the aeration pump; the first anoxic reactor, the second anoxic reactor, the third anoxic reactor and the fourth anoxic reactor are respectively provided with a rigid-flexible combination stirring paddle, and the first aerobic reactor, the second aerobic reactor, the first anoxic reactor, the second anoxic reactor, the third anoxic reactor, the fourth anoxic reactor and the fourth aerobic reactor are all provided with suspended spherical corrugated anaerobic ammonia-oxidizing bacteria fillers; the fifth aerobic reactor is connected to the second sedimentation tank through a continuous flow reactor outlet pipe, and the sludge outlet at the bottom of the second sedimentation tank is connected to the first aerobic reactor through a sludge return pump and a sludge return pipe;The appearance of the suspended spherical corrugated anaerobic ammonia oxidizing bacteria filler is a regular spherical corrugated structure with a plurality of small pores distributed on the surface. The surface layer and the gaps of the suspended spherical corrugated anaerobic ammonia oxidizing bacteria filler are enriched with anaerobic ammonia oxidizing bacteria; the check gate is a circular baffle structure, the upper end of which is connected to the partition through a rotating shaft, and the check gate can rotate freely; a hollow circle with a diameter smaller than the check gate is arranged on the side of the partition in the opposite direction of the water flow, that is, a check gate slot is formed to prevent the check gate from rotating in the opposite direction; the annular aeration disk includes an air inlet pipe, aeration pipes of different diameters, and aeration pipes of different diameters. Tubes and aeration holes, multiple aeration holes are evenly distributed on the aeration tubes, and their apertures are proportional to the diameter of the annular aeration disk; multiple aeration tubes are nested in sequence, and the diameters of the multiple aeration tubes gradually increase from the inside to the outside; the multi-stage three-phase separator includes a sludge settling inclined plate, an air collecting hood, an air collecting plate, an air collecting pipe and an air collecting chamber; multiple triangular air collecting hoods are arranged above the symmetrically arranged sludge settling inclined plates, the air collecting hoods are connected to the air collecting plates, the top of the air collecting plates is connected to the air collecting pipes, the top of the air collecting pipes is connected to the air collecting chambers, and the top of the air collecting chambers is connected to the air collecting ports. ; 2. The decentralized low-carbon sewage treatment device based on anaerobic ammonium oxidation according to claim 1 is characterized in that: The rigid-flexible combination stirring paddle comprises a stirring paddle shaft, a flexible curved stirring plate and a rigid straight stirring plate. The rigid-flexible combination stirring paddle has six identical rigid straight stirring plates equidistantly arranged on the upper and lower layers, and six identical flexible curved stirring plates arranged on the middle layer. Both ends of the flexible curved stirring plates are staggeredly connected to the rigid straight stirring plates on the upper and lower layers.

3. A treatment method using the decentralized low-carbon sewage treatment device based on anaerobic ammonia oxidation according to any one of claims 1 to 2, characterized in that: The steps include: 1) Inoculate the return sludge from the secondary sedimentation tank of the service area sewage treatment process, add it to the UASB reactor and the continuous flow reactor, and cultivate the sludge to the set concentration, and then add anaerobic ammonia-oxidizing bacteria filler to the aerobic reactor and the anoxic reactor; 2) Set the average hydraulic retention time in the UASB reactor and the continuous flow reactor respectively; control the discharge of excess sludge through the sludge discharge valve, and control the sludge age of the flocculent sludge in the reactor within the set time; 3) The sewage in the sewage inlet tank enters the continuous flow reactor in sections, of which 60% of the sewage enters the UASB reactor and 40% of the sewage enters the first anoxic reactor; the effluent of the UASB reactor enters the intermediate water tank and enters the first aerobic reactor through the third water inlet pump; the first aerobic reactor controls the aeration volume through a gas flow meter, and provides trace oxygen through an annular aeration disk to convert part of the ammonia nitrogen in the raw water into nitrite nitrogen, and the anaerobic ammonia oxidizing bacteria attached to the suspended spherical corrugated anaerobic ammonia oxidizing bacteria filler utilizes nitrite nitrogen and ammonia nitrogen in the raw water to generate nitrogen and nitrate nitrogen; then enters the third aerobic reactor, and oxygen is provided by the aeration pump to convert all the ammonia nitrogen in the effluent of the second aerobic reactor into nitrate nitrogen; the effluent of the third aerobic reactor and 40% of the raw water enter the first anoxic reactor at the same time, and under the stirring of the rigid-flexible combination stirring paddle, the anaerobic ammonia oxidizing bacteria utilize the organic matter produced by the in-situ fermentation of the sludge and the organic matter in the raw water to convert the nitrate nitrogen in the effluent of the third aerobic reactor into nitrite nitrogen, and then reacts with the ammonia nitrogen in 40% of the raw water to generate nitrogen and nitrate nitrogen; Subsequently, the effluent from the fourth anoxic reactor enters the fourth aerobic reactor. Under micro-aeration conditions, part of the ammonia nitrogen is oxidized to nitrite nitrogen. Anaerobic ammonia-oxidizing bacteria use the nitrite nitrogen and remaining ammonia nitrogen in the water to further convert them into nitrogen and nitrate nitrogen. Finally, it enters the fifth aerobic reactor. Nitrifying bacteria oxidize the remaining ammonia nitrogen in the water under sufficient aeration. The effluent that meets the ammonia nitrogen standard enters the secondary sedimentation tank. 4) Part of the sludge from the secondary sedimentation tank is returned to the first aerobic reactor through the sludge return pump, and the sludge return ratio is controlled to be 50%. The remaining sludge is discharged from the system through the sludge discharge gate valve.

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