Sewage treatment equipment for enhancing nitrogen removal and phosphorus recovery

Abstract

The utility model relates to sewage treatment equipment for enhancing nitrogen removal and phosphorus recovery, which comprises a biological reaction tank, a turntable filter tank, a phosphorus recovery device and a high-density sedimentation tank which are sequentially communicated, and the biological reaction tank is mainly used for providing an ecological environment for microbial populations so as to promote degradation and decrement of organic substances; an iron-carbon filler is arranged in the phosphorus recovery device and is used for converting phosphorus in the sewage into iron phosphate and separating and recovering the iron phosphate; a water outlet pipe of the phosphorus recovery device is communicated with the high-density sedimentation tank, and the high-density sedimentation tank is used for concentrating and precipitating sludge in water and clarifying and collecting water. The equipment provided by the utility model is simple in structure, can be transformed on the basis of an original biochemical pool, is convenient to transform, does not increase the occupied area, and is small in maintenance amount; the equipment is simple in structure, low in investment and operation cost and convenient to manage, has the cost advantage compared with an activated sludge process needing sludge treatment, can realize recovery of phosphorus resources in sewage when being used for treating the sewage, and is high in purity of recovered iron phosphate, few in impurities and good in resource utilization prospect.

Description

Technical Field

[0001] The utility model relates to sewage treatment equipment with enhanced denitrification and phosphorus recovery, belonging to the technical field of sewage treatment equipment. Background Art

[0002] With the continuous improvement of environmental laws and regulations and the continuous enhancement of public environmental awareness, on the one hand, the emission standards of urban sewage treatment plants are becoming increasingly stringent, and urban sewage treatment is facing increasing pressure, requiring sewage treatment plants to have better effluent quality and better meet environmental protection requirements. On the other hand, urban sewage treatment plants themselves are also paying more attention to technological innovation based on traditional processes. By introducing new technologies, new processes and new equipment, the treatment efficiency and treatment level of sewage treatment plants are improved, while reducing operating costs and energy consumption. This is to solve some of the problems existing in traditional sewage treatment processes, such as the need for large investment and operating costs, unstable results, ineffective removal of nitrogen and phosphorus, and low resource recovery and utilization rates. Therefore, there is an urgent need to develop a sewage treatment technology and equipment that is efficient, environmentally friendly, and low-cost.

[0003] Phosphorus is a scarce and critical resource. Natural phosphate rock is decreasing annually due to mining. However, it is estimated that phosphorus discharged from municipal sewage treatment plants can only meet approximately 15-20% of human phosphorus needs. Therefore, phosphorus recovery from wastewater is essential. Currently, phosphorus recovery from municipal sewage treatment plants both domestically and internationally primarily targets residual sludge from biological phosphorus removal (BPR) processes. High-concentration phosphate is obtained from sludge concentration, anaerobic fermentation supernatant, and sludge filtrate. Phosphorus products such as struvite and calcium phosphate are then recovered through physical and chemical methods such as chemical precipitation and crystallization. This phosphorus recovery method relies on the BPR process to bioaccumulate low-concentration phosphates in municipal sewage into activated sludge. By releasing or extracting phosphorus from the sludge, a phosphorus-rich solution is obtained that meets recovery requirements. However, the BPR process is still primarily a process focused on the conversion and removal of organic matter, where large amounts of wastewater organic matter are converted into microbial cells, consuming significant amounts of oxygen. If, in the urban sewage treatment process whose main goal is resource utilization, the low-carbon and low-phosphorus sewage after organic matter recovery will be difficult to meet the growth and metabolic needs of activated sludge in the traditional BPR process, then the way to obtain high-concentration phosphate through this side stream mode will no longer exist, and new process equipment will be needed to achieve the enrichment of phosphate in low-carbon and low-phosphorus sewage.

[0004] Currently, the main treatment and disposal methods for excess sludge are dehydration followed by incineration, landfill disposal, and agricultural utilization. However, sludge incineration is prohibitively expensive, and heavy metals pose safety risks for agricultural use. Consequently, the vast majority of excess sludge is disposed of in landfills. Landfill disposal presents significant challenges, including contamination of land and groundwater with Pi, heavy metals, and toxic organic matter, generation of toxic and hazardous gases, and the occupation of significant land. This has become a significant challenge plaguing urban development and impacting the human living environment. Therefore, reducing sludge production at the source is a pressing technical challenge that needs to be addressed. Utility Model Content

[0005] (1) Technical issues to be resolved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the utility model provides a sewage treatment equipment with enhanced denitrification and phosphorus recovery.

[0007] (2) Technical solution

[0008] In order to achieve the above-mentioned purpose, the main technical solutions adopted by this utility model include:

[0009] A sewage treatment device with enhanced denitrification and phosphorus recovery comprises a bioreactor, a rotary filter, a phosphorus recovery device and a high-density sedimentation tank connected in sequence. The bioreactor is mainly used to provide an ecological environment for microbial communities to promote the degradation and reduction of organic matter. The outlet pipe of the bioreactor is connected to the water inlet of the rotary filter, and the outlet pipe of the rotary filter is connected to the phosphorus recovery device. The phosphorus recovery device is provided with iron-carbon fillers for converting phosphorus in sewage into iron phosphate and separating and recovering the iron phosphate. The outlet pipe of the phosphorus recovery device is connected to the high-density sedimentation tank, which is used to concentrate and precipitate sludge in the water, clarify it and collect water.

[0010] As described above, the sewage treatment equipment preferably comprises an anaerobic tank, an anoxic tank, an aerobic tank, a protozoan growth tank, an aeration plate and a blower connected in sequence, wherein the aeration plate is arranged at the bottom of the aerobic tank and the protozoan growth tank, and the blower is connected to the aeration plate through a pipeline.

[0011] Furthermore, there are 2 anaerobic tanks, 2 to 4 anoxic tanks, 3 to 4 aerobic tanks, and 1 to 2 protometazoan growth tanks. Fixed carbon fiber fillers are arranged in the anaerobic tanks and the anoxic tanks, and the fillers are arranged in parallel with an interval of 8 to 12 cm. Two adjacent tanks are connected through flow holes. A protometazoan dosing device is also provided above the protometazoan growth tank.

[0012] In the sewage treatment equipment as described above, preferably, the mud outlet pipe at the bottom of the rotary filter is connected to the anaerobic tank through a first sludge return pump, and the mud outlet pipe at the bottom of the aerobic tank is connected to the anaerobic tank through a second sludge return pump, so as to increase the sludge concentration in the anaerobic tank.

[0013] The sewage treatment equipment as described above is further preferably provided with a first intermediate water tank between the rotary filter and the phosphorus recovery device, and an air-water backwash return pipe connected to the upper end of the iron-carbon micro-electrolysis tank is provided at the upper end of the first intermediate water tank.

[0014] In the sewage treatment equipment as described above, preferably, the phosphorus recovery device includes an iron-carbon micro-electrolysis tank, an iron phosphate separator, and an iron phosphate storage tank that are connected in sequence; wherein, an iron-carbon filler is provided in the iron-carbon micro-electrolysis tank, and the lower end discharge port of the iron-carbon micro-electrolysis tank is connected to the iron phosphate separator through a first pipe, and an electromagnetic valve is provided between the iron-carbon micro-electrolysis tank and the iron phosphate separator on the first pipe; a backwash air pipe is also connected to the first pipe; the outlet pipe of the rotary filter is connected to the first pipe through a solenoid valve; and the lower end of the iron phosphate separator is connected to the iron phosphate storage tank through a pipe.

[0015] In the sewage treatment equipment as described above, preferably, a second intermediate water tank connected to each other is provided between the phosphorus recovery device and the high-density sedimentation tank, the outlet pipe of the iron phosphate separator is connected to the inlet pipe of the second intermediate water tank, and the upper end of the iron-carbon micro-electrolysis tank is also provided with a pipe connected to the second intermediate water tank through an electromagnetic valve.

[0016] As described above, the sewage treatment equipment, preferably, the pipe at the bottom of the second intermediate water tank is connected to the high-density sedimentation tank through a lifting pump, and the high-density sedimentation tank includes a coagulation tank, a flocculation tank and a sedimentation tank connected in sequence, and a stirring device is provided in the coagulation tank and the flocculation tank. Furthermore, the coagulation tank and the flocculation tank are set separately or combined together, and a coagulant sampling port is provided at the upper part of the coagulation tank; a flocculant sampling port is provided at the upper part of the flocculation tank.

[0017] As described above, the sewage treatment equipment is preferably provided with a water inlet area, a sludge recovery area and an inclined tube clarification area in the sedimentation tank; scum collectors are provided in the water inlet area and the sludge recovery area along the entire width of the tank to separate the sludge from the water and discharge it; a partition is provided at the bottom of the sedimentation tank to divide the sedimentation tank into a water inlet area and a sludge recovery area, an inclined plate is provided below the sludge recovery area to divide the sludge recovery area into a water inlet area and a sludge recovery area, a scraper is provided below the inclined plate in the sludge recovery area, and a sludge return pipe and a sludge discharge pipe are provided below the scraper; above the sludge recovery area is the inclined tube clarification area, the inclined tube clarification area is provided with a water collection channel and a water collection weir, multiple rows of inclined tubes are provided below the water collection weir, and an outlet pipe is provided on one side of the water collection weir.

[0018] (3) Beneficial effects

[0019] The beneficial effects of the utility model are:

[0020] The utility model provides a sewage treatment device with enhanced denitrification and phosphorus recovery. The phosphorus recovery device is used to recover phosphorus resources in sewage. The recovered iron phosphate has high purity, few impurities, and good prospects for resource utilization. In addition, the phosphorus recovery device is used to recover phosphorus at a lower cost than directly adding PAC and PAM, has a high degree of automation, and can reduce the operating cost of phosphorus recovery. In the sewage treatment operation project, the equipment of the utility model improves the sewage treatment effect, reduces sludge production, and recovers phosphorus resources through the coupling of biofilm, activated sludge process, phosphorus recovery and high-density sedimentation tank. The biofilm and the regular addition of protozoa can reduce the sludge production rate by 50% to 90% compared with the activated sludge process.

[0021] The sewage treatment equipment with enhanced denitrification and phosphorus recovery provided by the present invention has a simple structure and can be modified on the basis of the original biochemical pool mainly by adding fillers. The modification is convenient, the operation is automatic, the floor space is not increased, and the maintenance requirement is small; the investment and operating costs are low, the management is convenient, and compared with the activated sludge method which requires sludge treatment, it has a cost advantage.

[0022] The utility model provides sewage treatment equipment with enhanced denitrification and phosphorus recovery, which can be used to simultaneously remove nitrogen and phosphorus from sewage, and has high treatment effect, low cost, simple operation and good stability; it is particularly suitable for cost-reduction and efficiency-enhancing transformation of existing projects, and can also be used to reduce organic sludge production and recover phosphorus in new sewage treatment projects; it is of great significance to the development and promotion of sewage treatment technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is a schematic diagram of the internal structure of the biological reaction tank in Example 1 provided by the present utility model;

[0024] Figure 2 A schematic structural diagram of the biological reaction pool in Example 1 provided by the present utility model;

[0025] Figure 3 A schematic structural diagram of the phosphorus recovery device in Example 1 provided for the utility model;

[0026] Figure 4 This is a schematic structural diagram of the high-density sedimentation tank in Example 1 provided for the utility model.

[0027] [Description of Reference Numerals]

[0028] 1: anaerobic tank;

[0029] 1-1: Filler

[0030] 1-2: Aeration plate

[0031] 2: Anoxic pool;

[0032] 3: Aerobic pool;

[0033] 4: First protometazoan growth pool;

[0034] 5: Second protometazoan growth pool;

[0035] 6: Blower;

[0036] 7: flow hole;

[0037] 8: DC (integrated online monitoring instrument);

[0038] 9: Water inlet pump;

[0039] 10: Water inlet electric valve;

[0040] 11: flow meter;

[0041] 12: effluent pump;

[0042] 13: Rotary disc filter;

[0043] 14: First sludge return pump;

[0044] 15: Second sludge return pump;

[0045] 16: Protozoan dosing device;

[0046] 17: First intermediate pool;

[0047] 18: Iron-carbon micro-electrolysis tank;

[0048] 19: Iron-carbon filler;

[0049] 20: valve;

[0050] 21: Backwash air pipe;

[0051] 22: Iron phosphate separator;

[0052] 23: Iron phosphate storage tank;

[0053] 24: Second intermediate pool;

[0054] 25: Electric valve. DETAILED DESCRIPTION

[0055] The present invention uses bio-chain technology to enhance sewage denitrification and reduce sludge production, while coupling micro-electrolysis to recover phosphorus, thereby achieving the goals of sewage quality improvement and efficiency enhancement, sewage resource utilization and sludge reduction.

[0056] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings. Unless otherwise specified, the technical means used in the embodiments are conventional means well known to those skilled in the art.

[0057] Example 1

[0058] A sewage treatment device for enhanced denitrification and phosphorus recovery, used for sewage treatment, comprises a bioreactor, a rotary filter, a phosphorus recovery device, and a high-density sedimentation tank, which are connected in sequence. The bioreactor is primarily used to provide an ecological environment for microbial communities and metazoans, and is used to promote the degradation and reduction of organic matter. An air inlet pipe for an aeration device is also connected to the upper portion of the bioreactor. The outlet pipe of the bioreactor is connected to the water inlet of the rotary filter, which is also connected to the phosphorus recovery device. The phosphorus recovery device is equipped with an iron-carbon micro-electrolysis tank filled with iron-carbon filler, an iron phosphate separator, and an iron phosphate storage tank. The phosphorus recovery device is used to convert phosphorus in sewage into iron phosphate and recover and separate the iron phosphate. The outlet pipe of the phosphorus recovery device is connected to the high-density sedimentation tank, which is used to concentrate and precipitate sludge in the water, clarify the water, and collect it.

[0059] Specifically, the bioreactor is sequentially equipped with an anaerobic zone, an anoxic zone, an aerobic zone, a protozoan growth zone, and a protozoan feeding tank. The supporting equipment includes: water inlet pumps, valves, flow meters, pipes, and instruments. Figure 1 As shown, the anaerobic zone typically has two anaerobic tanks 1 connected in series, the anoxic zone has two to four anoxic tanks 2 connected in series, the aerobic zone has three to four aerobic tanks 3 connected in series, and the protometazoan growth zone has one to two protometazoan growth tanks 4. The anaerobic and protometazoan growth zones are divided into 8 to 12 zones. Adjacent tanks are connected by flow holes. Fixed carbon fiber packing 1-1 is installed in the anaerobic, anoxic, and first aerobic tanks, arranged in parallel and spaced 8 to 12 cm apart. Aeration plates 1-2 are installed in the remaining aerobic and protometazoan growth tanks.

[0060] When the equipment is running, fixed carbon fiber filler A is set in the anaerobic tank, and the fillers are arranged in parallel with an interval of 8 to 12 cm. After a period of sludge cultivation, biofilm A is formed on the fixed filler A. Fixed carbon fiber filler B is set in the anoxic tank, and the fillers are arranged in parallel with an interval of 8 to 12 cm. After a period of sludge cultivation, biofilm B is formed on the fixed carbon fiber filler B. Fixed carbon fiber filler C is set in the first aerobic tank, and the fillers are arranged in parallel with an interval of 8 to 10 cm. After a period of sludge cultivation, biofilm C is formed on the fixed filler C.

[0061] Aeration pipes are set at the upper end of the anaerobic zone and the anoxic zone, and the aeration plates connected to the aeration pipes are set at the bottom of the aerobic zone and the metazoan growth zone. The aeration pipes and the aeration plates are connected to the blower through the air pipe, and the blower supplies aeration. Since the aeration volume needs to be precisely controlled, valves and flow meters are installed on the connecting pipelines. The aeration valve opening is adjusted according to the dissolved oxygen content in the water to determine the aeration flow rate.

[0062] In a preferred embodiment, Figure 2 As shown in FIG, the anaerobic zone is equipped with two anaerobic tanks 1, the anoxic zone is equipped with two anoxic tanks 2, the aerobic zone is equipped with six aerobic tanks 3, and the protometazoan growth zone is equipped with two protometazoan growth tanks, a first protometazoan growth tank 4, and a second protometazoan growth tank 5. Upper and lower flow holes 7 are sequentially provided on the partition plate between adjacent tanks. Aeration plates 1-2 are located at the bottom of the aerobic tanks 3. Aeration pipes and aeration plates 1-2 are connected to blowers 6 via air pipes, and valves and flow meters are installed on the connecting pipes. A DC (integrated online monitoring instrument) 8 is installed in the first tank of each zone to measure dissolved oxygen, pH, and other parameters. A water inlet pipe is provided at the front end of the anaerobic tank 1, which is equipped with a water pump 9, an electric water inlet valve 10, and a flow meter 11. The second anaerobic tank 1 is also provided with an effluent pump 12. The last tank, the second protometazoan growth tank 5, is connected to a rotary filter 13. The bottom of the rotary filter 13 is connected to a first sludge return pump 14. The bottom of the last aerobic tank 3 is connected to a second sludge return pump 15. The first sludge return pump 14 and the second sludge return pump 15 are connected to the first anaerobic tank 1 through a pipeline. A protometazoan dosing device 16 is also provided above the first protometazoan growth tank 4 and the second protometazoan growth tank 5.

[0063] The protometazoan growth zone is primarily designed to cultivate metazoans, which consume excess sludge. This, in turn, further improves effluent quality and reduces effluent turbidity. To improve sludge consumption efficiency in the protometazoan growth zone and reduce periods of slow growth, a protometazoan dosing tank is installed. This direct dosing of protometazoans maintains sludge reduction, ultimately ensuring that the effluent from the biochain system meets Class I A or Quasi-Class IV standards, excluding phosphorus. For Class I A standards, the system residence time is shorter; for Quasi-Class IV standards, the residence time is longer. If total nitrogen levels are high, a carbon source may also be added.

[0064] The process flow of the biochain system is as follows: sewage is lifted to the anaerobic zone by a lifting pump, with valves and flow meters used to accurately control the water flow rate. At the same time, the sludge returned from the sludge return pump of the post-biological zone is stirred by a submersible mixer, and the sewage and the returned sludge are fully mixed. In the anaerobic zone, the oxygen concentration is very low. At this time, organic matter is decomposed into small molecular hydrolysis products by bacterial flocs, and some organic matter is ammonified, while releasing phosphorus.

[0065] The effluent from the anaerobic zone enters the anoxic zone, and simultaneously enters the return sludge that flows back from the bottom of the protozoan growth zone through the internal return pump. The main function of the anoxic zone is to use anoxic microorganisms to reduce nitrates in the sewage into nitrogen gas in the absence of oxygen, thereby achieving the purpose of denitrification. This is achieved through the anoxic microorganisms in the biofilm and the return sludge at the bottom of the metazoan growth zone, using the nitrate nitrogen carried in the return sludge as an electron acceptor to carry out rapid denitrification, while preparing for the full release of anaerobic phosphorus removal and reducing the total nitrogen concentration in the sewage.

[0066] The effluent from the anoxic zone enters the aerobic zone, where air is introduced through a blower and aeration system. Aerobic microorganisms absorb oxygen from the air in the sewage and utilize organic pollutants and oxygen for growth. Under aerobic conditions, the microorganisms nitrify ammonia nitrogen in the domestic sewage to produce nitrates. During their growth, the microorganisms further degrade organic matter, which facilitates the nitrification reaction of aerobic microorganisms using ammonia nitrogen in the wastewater to produce nitrates and nitrites, thereby enhancing nitrification.

[0067] The effluent from the aerobic zone enters the metazoan growth zone. This zone is home to many protozoans, and the growth of protozoans consumes a large amount of oxygen and bacteria. Therefore, a blower and an aeration system are required to introduce air. The oxygen in the air is absorbed by the metazoans in the sewage. The protozoan growth zone is mainly inhabited by protozoans, rotifers, nematodes, earthworms and other organisms, which feed on tiny microorganisms and organic particles. The microorganisms in the sewage that serve as food include various bacterial flocs such as nitrifying bacteria and denitrifying bacteria. Through the food chain, sludge production is greatly reduced, achieving the goal of sludge reduction. Return ratio: 1) Internal sludge return: The sludge is returned from the bottom outlet of the aerobic zone to the anaerobic zone via sludge return pump 1, with the return rate controlled at 100% to 300%; 2) Rotary disc filter sludge return: The sludge at the bottom of the rotary disc filter is returned to the anaerobic zone via a pipeline, with the return rate controlled at 50% to 100%; the sludge is discharged to the second anaerobic zone intermittently, generally once every 10 to 15 days. When the SS content is high, the sludge discharge interval is shorter, and when the SS content is low, the sludge discharge interval is longer, generally not exceeding 15 days. Because the biofilm shedding cycle is about one month, to ensure the timely discharge of the shedding sludge, the interval is generally not more than 15 days;

[0068] At this time, the effluent of the biological reactor meets the Class A or quasi-Class IV standards except for phosphorus, and its SS, COD, ammonia nitrogen and total nitrogen are low. The effluent is relatively clear and contains a small amount of activated sludge. The concentration is generally 10-50 mg / L, with an average of about 30 mg / L. In order to reduce the activated sludge in the effluent and reduce the effluent SS, a rotary filter is set at the end of the biological chain system to filter out the activated sludge in the effluent. After filtration, the water is dephosphorized and recycled. The concentrated activated sludge after filtration is returned to the anaerobic tank through the first sludge return pump 14 and returned to the anaerobic tank together with the return sludge from the second sludge return pump 15 at the bottom of the aerobic zone, thereby increasing the sludge concentration in the anaerobic tank.

[0069] When the effluent from the rotary filter enters the phosphorus recovery device, the purpose of the phosphorus recovery device is to recover phosphorus in the sewage, thereby realizing phosphorus recovery.

[0070] The phosphorus recovery device includes an iron-carbon micro-electrolysis tank, an iron phosphate separator, and an iron phosphate storage tank connected in sequence. Figure 3 As shown, the water outlet of the rotary filter is connected to the water inlet of the first intermediate water tank 17 through a pipe. The upper end of the first intermediate water tank 17 is provided with an air-water backwash pipe connected to the upper water inlet of the iron-carbon micro-electrolysis tank 18. The iron-carbon micro-electrolysis tank 18 is provided with an iron-carbon filler 19. The lower end discharge port of the iron-carbon micro-electrolysis tank 18 is provided with a first pipe connected to the lower end of the first intermediate water tank 17. The first branch of the first pipe is provided with a valve 20 and connected to the lower end of the first intermediate water tank 17. The first pipe at the lower end of the iron-carbon micro-electrolysis tank 18 is also connected to a backwash air pipe 21. The lower end of the iron-carbon micro-electrolysis tank 18 is connected to an iron phosphate separator 22 through a pipe, and the lower end of the iron phosphate separator 22 is connected to an iron phosphate storage tank 23 through a pipe. The upper end of the iron-carbon micro-electrolysis tank 18 is also connected to a second intermediate water tank 24 through a pipe, and the pipe between the two is also provided with an electric valve 25.

[0071] When the device is in operation, wastewater enters the iron-carbon micro-electrolysis tank. The phosphorus in the wastewater reacts with the surface of the spherical iron-carbon filler through a micro-electrolysis reaction, forming dense iron phosphate on the surface of the filler. When the surface coverage reaches 50% or more, air-water backwashing is required to remove the dense iron phosphate from the surface. The detached iron phosphate settles to the bottom of the iron-carbon micro-electrolysis tank and, driven by gravity and water flow, enters the iron phosphate separator. The iron phosphate is separated from the water by the separator and enters a storage tank. Once a sufficient amount is stored, it is sent to fertilizer plants, for use as phosphate fertilizer. The air-water backwashing sequence is: 1) air wash for 5 minutes; 2) mixed air-water wash for 5 minutes. The backwashing time is determined by the phosphorus removal rate; backwashing is repeated when the removal rate is less than 50%.

[0072] After the wastewater passes through the phosphorus recovery system, the phosphorus removal rate is 50% to 70%, and the effluent TP is around 0.5 mg / L. If the quasi-Class IV standard is required at this time, a high-density sedimentation tank is required to further reduce the phosphorus content in the effluent. In this case, polyaluminum chloride (PAC) and polyacrylamide (PAM) are added to the high-density sedimentation tank to further remove dissolved matter and suspended solids (SS) in the water. The high-density sedimentation tank includes a coagulation and flocculation tank equipped with an agitator and a sedimentation tank. The sedimentation tank includes a high-efficiency inclined plate sedimentation tank and a sludge concentration area.

[0073] The structural diagram of the high-density sedimentation tank is as follows Figure 4 As shown, a pipe runs from the lower end of the second intermediate water tank 24, connecting it to a central barrel 28 located between the coagulation tank 26 and the flocculation tank 27 via a lift pump 25. A coagulant injection port is located above the coagulation tank, and a flocculant injection port is located above the flocculation tank. Adjacent to the flocculation tank 27 is a sedimentation tank 28, which is equipped with an inlet area, a sludge recovery area, and an inclined tube clarification area. Scum collectors are installed along the entire width of the inlet and sludge recovery areas to separate scum from the water and discharge it. A partition is installed at the bottom of the sedimentation tank, dividing it into an inlet area and a sludge recovery area. Below the sludge recovery area is an inclined plate, below which is a sludge scraper 29. Above the sludge recovery area is a water collection channel 30 and a water collection weir 31 located in the inclined tube clarification area. The inclined plate is installed approximately 1 meter below the water level of the sedimentation tank. Below the weir 31 are multiple rows of inclined tubes 32, and one side of the weir 31 is equipped with an outlet pipe 33. A sludge return pipe 34 and a sludge discharge pipe 35 are provided at the bottom of the sedimentation tank 28 corresponding to the lower portion of the scraper 29 .

[0074] During operation, wastewater undergoes coagulation in the coagulation tank located in front of the high-density sedimentation tank. PAC is added as a coagulant to destabilize suspended colloids and remove some soluble phosphates through chemical precipitation. The entire coagulation process utilizes dynamic coagulation, with both the inlet and outlet water flows controlled at the surface. The wastewater then flows into the flocculation tank. Flocculation is also a physical-mechanical process, where floccules grow due to physical agitation and intermolecular forces, facilitating sedimentation. An anionic polymer coagulant aid (PAM) is added to the flocculation tank to enhance flocculation efficiency through adsorption and bridging. After coagulation and flocculation, the wastewater enters the sedimentation tank, which primarily consists of three sections: the inlet and extended sedimentation zones, the sludge recovery zone, and the inclined tube clarification zone. a) Inlet and extended sedimentation zones: In the inlet and extended sedimentation zones, scum collectors located across the width of the sedimentation tank separate scum from the water for discharge. The sedimentation zone separates the heavier alum flocs (approximately 80% of the total SS content) and directs them to the sludge recovery zone, reducing the amount of sludge passing through the inclined plates and minimizing the risk of sludge accumulation and clogging. b) Sludge Recovery Zone: The settled sludge slides down the inclined plates and falls to the bottom of the tank, where it forms a flocculent layer (the floc contact layer). This layer increases the number of crystallization nuclei, reduces coagulant consumption, and increases floc density, thereby accelerating settling. After the sludge is concentrated at the bottom of the tank, a slow-rotating scraper continuously scrapes the sludge into a central sludge collection pit. The scraper's grating further enhances sludge concentration. The concentrated sludge is controlled by a set program or a mud level meter to achieve an optimized sludge concentration and is intermittently discharged to the sludge treatment system via a sludge discharge screw pump. c) Inclined Plate Clarification Zone: The inclined plates and their associated support system. Clarified water collection system: The inclined plates have a large gap (80mm) and an inclination angle (60°), allowing the sludge to slide down the plates under gravity. Furthermore, the low Reynolds coefficient (approaching laminar flow) and the plate structure (increased wetted perimeter and settling area) in the inclined plate area ensure efficient sludge-water separation. Clarified water from the upper layer of the inclined plates is collected in a sump. To facilitate water distribution during low flow rates, the effluent weir on the sump can be triangular or rectangular. The clear water from the sewage treated in the inclined plate clarification area meets the quasi-Class IV effluent quality, meeting the "Special Emission Limits" requirements of the "Pollutant Discharge Standards for Urban Wastewater Treatment Plants" (Draft for Comment).

[0075] The bioreactor provided by the present invention utilizes the interaction and synergy of microorganisms through the biochain and performs treatment together with metazoans during operation, utilizes the metabolic process of the microorganisms themselves to achieve material-energy conversion to complete the degradation of pollutants in water, promotes the degradation and reduction of organic matter through the ecological environment of the microbial community, reduces the addition of external energy and reagents, thereby reducing secondary pollution and achieving the removal of nitrogen and phosphorus in sewage, with high treatment effect, and significantly reduces sludge production through metazoans, achieving the purpose of sludge reduction; and the bioreactor equipment cost, energy consumption and operation and maintenance costs are low; the biochain purification technology can achieve a high purification effect on pollutants within a controllable time and is highly efficient; at the same time, because the biochain water treatment technology is designed based on the principles of natural ecosystems, its treatment process meets the requirements of environmental protection and can reduce pollution to the environment; in addition, the biochain treatment forms a relatively stable microbial community with good operational stability and resistance to water quality shocks, can domesticate adaptive biochains under different water quality conditions, and is more suitable for diverse and complex treatment environments, thus being a green, low-carbon and sustainable water treatment technology.

[0076] The micro-electrolysis filler adopted by the utility model adopts iron-carbon micro-electrolysis, which can efficiently degrade organic matter in sewage and remove pollutants. The treatment effect is obvious, the effluent water quality is stable, and nitrogen and phosphorus in sewage can be removed in a short time with a high removal rate of more than 90%. It can achieve efficient treatment at a lower voltage, is easy to operate and maintain, and can reduce energy consumption and operating costs. Chemical agents need to be added during its operation, and no agent residues and secondary pollution will be generated, which meets environmental protection requirements.

[0077] The sewage treatment equipment with enhanced denitrification and phosphorus recovery provided by the utility model can be used to simultaneously remove nitrogen and phosphorus from sewage, and has high treatment effect, low cost, simple operation and good stability, and can be widely used in the treatment of domestic sewage and industrial sewage.

[0078] When the equipment of the utility model is used, it combines the biological chain and iron-carbon micro-electrolysis technology and can be used for sewage treatment with different water qualities and types of pollutants. It can be applied to sewage treatment plants of different sizes and has good application prospects.

[0079] Example 2

[0080] During operation, based on Example 1, the apparatus includes five anoxic zones, six aerobic zones, and one protometazoan growth zone, with a total of 12 zones from the anaerobic to the protometazoan growth zones. The apparatus also includes: 1) internal sludge recirculation: sludge from the bottom outlet of the aerobic zone is returned to the anaerobic zone via a second sludge recirculation pump, with the recirculation rate controlled at 250%; and 2) rotary disc filter sludge recirculation: sludge from the bottom of the rotary disc filter is returned to the anaerobic zone via a pipeline, with the recirculation rate controlled at 5%. The sewage treatment results are: inlet water quality: CODcr: 216 mg / L, ammonia nitrogen: 58 mg / L, TN: 68 mg / L, TP: 5.1 mg / L; and outlet water quality: CODcr: 26 mg / L, ammonia nitrogen: 1.6 mg / L, TN: 14 mg / L, TP: 0.26 mg / L. The sludge reduction effect reaches 82%. The phosphorus recovery rate reaches 60% (the phosphorus recovery rate is calculated by dividing the recovered phosphorus amount by the phosphorus content in the effluent of the biological chain system).

[0081] Comparative Example 1

[0082] This comparative example is based on Example 1. When the conventional A2O process + deep treatment is used, that is, no carbon fiber filler and phosphorus recovery are set to treat the sewage, when the inlet water quality is CODcr: 216mg / L, ammonia nitrogen: 32mg / L, TN: 40mg / L, TP: 3.2mg / L, the final effect obtained is that the effluent water quality is CODcr: 46mg / L, ammonia nitrogen: 0.6mg / L, TN: 14mg / L, TP: 0.4mg / L. The sludge output is large, and the carbon source and phosphorus removal agent consumed are large, and no phosphorus is recovered. According to calculations, the use of the technology of the present invention, compared with the conventional A2O process + deep treatment process, the sludge amount is reduced by 80%, the carbon source addition is reduced by 50%, and the phosphorus removal agent addition is reduced by 60%. At the same time, phosphate is harvested and the phosphorus resource is recycled.

[0083] Comparative Example 2

[0084] This comparative example is based on Example 1, but without phosphorus recovery treatment. When the influent quality was CODcr: 216 mg / L, ammonia nitrogen: 32 mg / L, TN: 40 mg / L, and TP: 3.2 mg / L, the final effluent quality was CODcr: 30 mg / L, ammonia nitrogen: 1.3 mg / L, TN: 14 mg / L, and TP: 0.9 mg / L. The sludge reduction effect reached 80%.

[0085] Comparative Example 3

[0086] This comparative example, based on Example 1, differs from the present invention in that it uses a conventional A / O process without the use of carbon fiber fillers. With influent quality of 216 mg / L CODcr, 32 mg / L ammonia nitrogen, 40 mg / L TN, and 3.2 mg / L TP, the final effluent quality achieved was 46 mg / L CODcr, 0.9 mg / L ammonia nitrogen, 14 mg / L TN, and 0.46 mg / L TP. Phosphorus recovery was approximately 30%. There was no sludge reduction effect, and the required reagents increased, resulting in high operating costs.

[0087] The above description is merely a preferred embodiment of the present invention and does not constitute any other limitation thereto. Any person skilled in the art may utilize the above disclosed technical content to modify or modify the above disclosed embodiments into equivalent embodiments. However, any simple modifications, equivalent variations, and modifications made to the above embodiments that do not depart from the technical content of the present invention and are based on the technical essence of the present invention shall still fall within the scope of protection of the present invention.

Claims

1. A sewage treatment plant for enhanced denitrification and phosphorus recovery, characterized in that It includes a biological reaction tank, a rotary filter, a phosphorus recovery device and a high-density sedimentation tank that are connected in sequence. The biological reaction tank is mainly used to provide an ecological environment for microbial communities to promote the degradation and reduction of organic matter; the outlet pipe of the biological reaction tank is connected to the water inlet of the rotary filter, and the outlet pipe of the rotary filter is connected to the phosphorus recovery device. The phosphorus recovery device is provided with iron-carbon filler for converting phosphorus in sewage into iron phosphate and separating and recovering the iron phosphate; the outlet pipe of the phosphorus recovery device is connected to the high-density sedimentation tank, and the high-density sedimentation tank is used to concentrate and precipitate sludge in the water, clarify and collect water.

2. The sewage treatment equipment according to claim 1, characterized in that: The biological reaction tank includes an anaerobic tank, an anoxic tank, an aerobic tank, a protozoan growth tank, an aeration plate and a blower which are connected in sequence. The aeration plate is arranged at the bottom of the aerobic tank and the protozoan growth tank, and the blower is connected to the aeration plate through a pipeline.

3. The sewage treatment equipment according to claim 2, characterized in that: The method comprises two anaerobic tanks, two to four anoxic tanks, three to four aerobic tanks, and one to two protometazoan growth tanks. Fixed carbon fiber fillers are arranged in the anaerobic tanks and the anoxic tanks, and the fillers are arranged in parallel with an interval of 8 to 12 cm. Two adjacent tanks are connected via a flow hole. A protometazoan dosing device is also provided above the protometazoan growth tank.

4. The sewage treatment equipment according to claim 1, characterized in that: The mud outlet pipe at the bottom of the rotary filter is connected to the anaerobic tank through the first sludge return pump, and the mud outlet pipe at the bottom of the aerobic tank is connected to the anaerobic tank through the second sludge return pump to increase the sludge concentration in the anaerobic tank.

5. The sewage treatment equipment according to claim 4, characterized in that: A first intermediate water tank is provided between the rotary filter and the phosphorus recovery device, and an air-water backwash return pipe communicating with the upper end of the iron-carbon micro-electrolysis tank is provided at the upper end of the first intermediate water tank.

6. The sewage treatment equipment according to claim 1, characterized in that: The phosphorus recovery device includes an iron-carbon micro-electrolysis tank, an iron phosphate separator, and an iron phosphate storage tank that are connected in sequence; wherein, an iron-carbon filler is provided in the iron-carbon micro-electrolysis tank, and the lower end discharge port of the iron-carbon micro-electrolysis tank is connected to the iron phosphate separator through a first pipe, and an electromagnetic valve is provided between the iron-carbon micro-electrolysis tank and the iron phosphate separator on the first pipe; a backwash air pipe is also connected to the first pipe; the water outlet pipe of the rotary filter is connected to the first pipe through the electromagnetic valve; and the lower end of the iron phosphate separator is connected to the iron phosphate storage tank through a pipe.

7. The sewage treatment equipment according to claim 6, characterized in that: A second intermediate water tank is provided between the phosphorus recovery device and the high-density sedimentation tank, which are interconnected. The outlet pipe of the iron phosphate separator is connected to the inlet pipe of the second intermediate water tank. The upper end of the iron-carbon micro-electrolysis tank is also provided with a pipe connected to the second intermediate water tank through an electromagnetic valve.

8. The sewage treatment equipment according to claim 7, characterized in that: The pipeline at the bottom of the second intermediate water tank is connected to the high-density sedimentation tank through a lifting pump. The high-density sedimentation tank includes a coagulation tank, a flocculation tank and a sedimentation tank connected in sequence. A stirring device is provided in the coagulation tank and the flocculation tank.

9. The sewage treatment equipment according to claim 8, characterized in that: The coagulation tank and the flocculation tank are set up separately or combined together; a coagulant adding port is provided on the upper part of the coagulation tank; and a flocculant adding port is provided on the upper part of the flocculation tank.

10. The sewage treatment equipment according to claim 8, characterized in that: The sedimentation tank is provided with a water inlet area, a sludge recovery area and an inclined tube clarification area; a scum collector is provided in the water inlet area and the sludge recovery area along the entire width of the tank for separating the scum from the water and discharging it; A partition is provided at the bottom of the sedimentation tank to divide the sedimentation tank into a water inlet area and a sludge recovery area. An inclined plate is provided below the sludge recovery area to divide the sludge recovery area into a water inlet area and a sludge recovery area. A scraper is provided below the inclined plate in the sludge recovery area, and a sludge return pipe and a sludge discharge pipe are provided below the scraper. Above the sludge recovery area is an inclined tube clarification area, which is provided with a water collection channel and a water collection weir. Multiple rows of inclined tubes are provided below the water collection weir, and an outlet pipe is provided on one side of the water collection weir.

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