Phosphorus-containing wastewater treatment system

Abstract

This invention relates to the field of water treatment technology, and more particularly to a phosphorus-containing wastewater treatment system. The system comprises, from bottom to top: a biological phosphorus removal reaction unit, an electrobiological oxidation adsorption unit, and a gas membrane separation unit. The biological phosphorus removal reaction unit includes an anaerobic tank and an aerobic tank arranged in parallel. The electrobiological oxidation adsorption unit includes an electrobiological phosphorus oxidation tank and a baffled adsorption tank arranged in parallel. The electrobiological phosphorus oxidation tank is located above the anaerobic tank, and its bottom is connected to the interior of the anaerobic tank through a first exhaust port. The baffled adsorption tank is located above the aerobic tank, and its bottom is connected to the interior of the aerobic tank through a second exhaust port. The gas membrane separation unit is located above the baffled adsorption tank, and its bottom is connected to the interior of the baffled adsorption tank through a fourth exhaust port. This phosphorus-containing wastewater treatment system, while performing biological phosphorus removal from phosphorus-containing wastewater, can also treat the accompanying phosphine gas and bioaerosols, helping to eliminate safety hazards and protect the atmospheric environment.

Description

Technical Field

[0001] This invention relates to the field of water treatment technology, and more particularly to a phosphorus-containing wastewater treatment system. Background Technology

[0002] Phosphorus is a major nutrient element causing eutrophication in water bodies. Eutrophication not only leads to the growth of algae but also causes a sharp decline in oxygen levels, affecting the survival of aquatic organisms such as fish. Phosphorus mainly originates from domestic sewage, industrial wastewater, and soil erosion. In domestic sewage, phosphorus from various detergents accounts for approximately 70%. Wastewater from industries such as chemical, papermaking, rubber, dyeing and textile printing, pesticides, coking, petrochemicals, fermentation, pharmaceuticals and medical treatment, and food processing often contains organophosphorus compounds.

[0003] Phosphorus removal methods for phosphorus-containing wastewater can be categorized into physicochemical phosphorus removal, biological phosphorus removal, and constructed wetland phosphorus removal. Compared to physicochemical methods, biological phosphorus removal requires virtually no additional chemical additives, and compared to constructed wetland methods, its equipment footprint is relatively smaller. Therefore, wastewater treatment plants currently typically employ biological phosphorus removal to treat phosphorus-containing wastewater. Biological phosphorus removal utilizes the biochemical action of polyphosphate-accumulating bacteria (PABs). The principle is that PABs can fully release polyphosphates within their cells under anaerobic conditions, and under aerobic conditions, they can absorb phosphorus from water beyond their physiological needs, converting it into polyphosphates within their cells. This forms phosphorus-rich biological sludge, which is then discharged from the system through sedimentation, achieving phosphorus removal from the wastewater. In recent years, with increasing environmental and health awareness, how to further optimize the environmental performance of biological phosphorus removal methods and reduce safety hazards has received increasing attention from those skilled in the art. Summary of the Invention

[0004] To solve or partially solve the problems existing in related technologies, the present invention provides a phosphorus-containing wastewater treatment system.

[0005] This invention provides a phosphorus-containing wastewater treatment system, which comprises, from bottom to top: a biological phosphorus removal reaction unit, an electrobiological oxidation adsorption unit, and a gas membrane separation unit; wherein,

[0006] The biological phosphorus removal reaction unit includes an anaerobic tank and an aerobic tank arranged in parallel. The anaerobic tank is provided with a first inlet and a first outlet, and the aerobic tank is provided with a second inlet, a second outlet, and an aeration port. The first outlet is connected to the second inlet via a liquid delivery pipeline, and a first circulation pump is installed on the liquid delivery pipeline. The second outlet is connected to a drainage pipeline and a first circulation pipeline. A first exhaust port and a second exhaust port are respectively provided on the top of the anaerobic tank and the aerobic tank.

[0007] The electrobiological oxidation adsorption unit includes an electrobiological phosphorus oxidation tank and a baffled adsorption tank arranged in parallel; the electrobiological phosphorus oxidation tank is located above the anaerobic tank, and its bottom is connected to the interior of the anaerobic tank through a first exhaust port; the baffled adsorption tank is located above the aerobic tank, and its bottom is connected to the interior of the aerobic tank through a second exhaust port.

[0008] The electrobiological phosphorus oxidation tank is equipped with a spray liquid inlet at the top and a third outlet at the bottom. A reaction zone is set between the spray liquid inlet and the third outlet, and biological packing material and electrodes are set in the reaction zone. The biological packing material is a porous packing material pre-inoculated with electroactive bacteria, and the electrodes are connected to an external power source. The spray liquid inlet is connected to a first circulation pipeline, and a second circulation pump is set on the first circulation pipeline. The third outlet is connected to a delivery pipeline through the second circulation pipeline. A third exhaust port is set at the top of the electrobiological phosphorus oxidation tank.

[0009] The baffled adsorption tank is equipped with adsorption packing and vertical baffles, and a fourth exhaust port is provided at the top.

[0010] The gas membrane separation unit is located above the baffled adsorption tank. It is equipped with a gas separation membrane assembly inside and is connected to the inside of the baffled adsorption tank through a fourth exhaust port at the bottom. The gas membrane separation unit is provided with an oxygen-enriched outlet and a fifth exhaust port at the top. The oxygen-enriched outlet is connected to the aeration port, and an air pump is provided between the oxygen-enriched outlet and the aeration port.

[0011] Furthermore, in the anaerobic tank, the first inlet is located below the first outlet; the anaerobic tank is provided with a first horizontal baffle between the first inlet and the first outlet.

[0012] Furthermore, in the aerobic tank, the second outlet is located above the aeration port, and the aeration port is located above the first inlet; the aerobic tank is equipped with an aeration pipe, a second horizontal baffle plate, and a membrane module; the aeration pipe is connected to the aeration port, is arranged horizontally, and has a plurality of aeration holes evenly distributed on its surface; the second horizontal baffle plate is arranged between the aeration pipe and the second inlet; the membrane module is arranged above the aeration pipe, and its outlet forms the second outlet; a sludge discharge port is also provided at the bottom of the aerobic tank.

[0013] Furthermore, the membrane module is a hollow fiber membrane module or a spiral wound membrane module.

[0014] Furthermore, a support plate is provided inside the electrobiological phosphorus oxidation tank, and the support plate is located above the third outlet; the biological packing is supported by the support plate, and a number of air guide holes are evenly opened on the support plate.

[0015] Furthermore, the porous filler is polyurethane.

[0016] Furthermore, the electrobiological phosphorus oxidation tank is equipped with a spray pipe, which is connected to the spray liquid inlet; the spray pipe is uniformly equipped with several sets of spray heads along the horizontal direction.

[0017] Furthermore, the electroactive bacterial species is one or two of Pseudomonas aeruginosa and Bacillus.

[0018] Furthermore, the electrode is a graphite electrode, a carbon felt electrode, or a carbon fiber electrode, and the electrode is arranged in a horizontal direction.

[0019] Furthermore, in the baffled adsorption tank, the adsorption packing material is activated carbon, ceramsite, diatomaceous earth, quartz sand, or molecular sieve.

[0020] The phosphorus-containing wastewater treatment system provided by this invention can have the following beneficial effects:

[0021] 1. The phosphorus-containing wastewater treatment system has a vertical three-layer structure, which makes full use of the vertical space and the characteristics of gas upward movement, simplifies the gas pipeline design, and reduces the equipment's footprint.

[0022] 2. This treatment system includes an electrobiological phosphorus oxidation tank and a baffled adsorption tank above the biological phosphorus removal reactor. These tanks are used to treat phosphine generated during anaerobic treatment and bioaerosol generated during aerobic treatment, respectively. Therefore, this phosphorus-containing wastewater treatment system can treat phosphine gas and bioaerosol generated simultaneously with the biological phosphorus removal from the wastewater, helping to eliminate safety hazards and protect the atmospheric environment.

[0023] 3. A portion of the liquid discharged from the aerobic tank of this treatment system is returned to the electrobiological phosphorus oxidation tank as nutrient solution and conductive liquid. The gas discharged from the baffled adsorption tank is separated and treated by a gas membrane separation unit, and the oxygen-enriched air is returned to the aerobic tank as supplementary aeration, saving energy. Therefore, this treatment system also achieves the reuse of oxygen and phosphorus resources.

[0024] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit the invention. Attached Figure Description

[0025] The above and other objects, features and advantages of the present invention will become more apparent from the more detailed description of exemplary embodiments of the invention in conjunction with the accompanying drawings, wherein the same reference numerals generally represent the same parts.

[0026] Figure 1 This is a schematic diagram of the structure of a phosphorus-containing wastewater treatment system shown in an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures

[0028] 1-Anaerobic tank

[0029] 11-First Inlet

[0030] 12-First outlet

[0031] 13-First exhaust port

[0032] 14-First horizontal baffle

[0033] 2-Aerobic tank

[0034] 21-Second Inlet

[0035] 22-Second outlet

[0036] 23-Aeration port

[0037] 24-Second exhaust port

[0038] 25-Aeration pipe

[0039] 26-Second Horizontal Baffle

[0040] 27-Membrane Module

[0041] 28-Sludge discharge port

[0042] 3-Electrobiological phosphorus oxidation pond

[0043] 31-Third outlet

[0044] 32-Biological packing material

[0045] 33-electrode

[0046] 34-Third exhaust port

[0047] 35-Spray pipe

[0048] 36-Support Plate

[0049] 4-Baffled Adsorption Tank

[0050] 41-Fourth exhaust port

[0051] 42-Adsorption packing

[0052] 43-Vertical baffle

[0053] 5-Gas Membrane Separation Unit

[0054] 51-Oxygen-enriched outlet

[0055] 52-Fifth exhaust port

[0056] 53-Gas Separation Membrane Module

[0057] P1 - Infusion Pipeline

[0058] P2 - First circulation pipeline

[0059] P3 - Second Circulation Pipeline Detailed Implementation

[0060] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0061] The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular forms “a,” “the,” and “the” used in this invention and the appended claims are also intended to include the plural forms unless the context clearly indicates otherwise. It should also be understood that the term “and / or” as used herein refers to and includes any or all possible combinations of one or more of the associated listed items.

[0062] It should be understood that although the terms "first," "second," "third," etc., may be used in this invention to describe various information, this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another. For example, without departing from the scope of this invention, first information may also be referred to as second information, and similarly, second information may also be referred to as first information. Thus, features defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0063] The inventors of this application have discovered through research that while biological phosphorus removal is effective in treating phosphorus in wastewater, microorganisms, unlike chemical agents, possess life and metabolic characteristics, thus generating other pollutants, primarily phosphine gas and bioaerosols. These two types of pollutants, if directly released into the atmosphere, will pollute the surrounding environment and harm human health. Specifically:

[0064] Studies have found that obligate anaerobic bacteria, such as phosphate-reducing bacteria, can reduce organic phosphorus compounds and inorganic phosphates in an anaerobic environment to phosphine. Phosphine is a gaseous, colorless, and highly toxic inorganic compound. Pure phosphine gas is colorless and odorless, but when metal phosphides produce phosphine gas, it often has an acetylene, garlic, or rotten fish odor. Inhalation of phosphine can affect the heart, respiratory system, kidneys, gastrointestinal tract, nervous system, and liver. Phosphine gas released into the air pollutes the surrounding environment and harms human health.

[0065] Biological phosphorus removal wastewater treatment systems contain a large number of microorganisms. Disturbed by aeration or mechanical agitation, some smaller microorganisms in the wastewater or sludge escape into the surrounding air, forming bioaerosols. Additionally, bioreactors treating waste gas contain a large number of microorganisms. Due to the impact of the incoming airflow, microorganisms attached to the packing surface are carried out of the bioreactor, also contributing to bioaerosol emissions. Bioaerosols typically refer to aerosols with an aerodynamic diameter of less than 100 μm containing microorganisms or other bioactive substances, including bacteria, fungi, viruses, endotoxins, as well as fungal spores, fern spores, and protozoa. Besides possessing the characteristics of general aerosols, they also exhibit infectivity and sensitization. Of the approximately 500 pathogenic bacteria worldwide, more than 100 are transmitted through aerosols, posing a threat to human health. Recent studies have also found that microbial aerosols are important precursors to smog formation.

[0066] Therefore, the inventors of this application considered that while using biological phosphorus removal to treat phosphorus-containing wastewater, the co-treatment of phosphine waste gas and bioaerosols could be achieved, which is of great significance for eliminating safety hazards and protecting the atmospheric environment.

[0067] This invention provides a phosphorus-containing wastewater treatment system; please refer to [link / reference]. Figure 1 It comprises, from bottom to top, a biological phosphorus removal reaction unit, an electrobiological oxidation adsorption unit, and a gas membrane separation unit 5; among which,

[0068] The biological phosphorus removal reaction unit includes an anaerobic tank 1 and an aerobic tank 2 arranged in parallel. The anaerobic tank 1 is provided with a first inlet 11 and a first outlet 12, and the aerobic tank 2 is provided with a second inlet 21, a second outlet 22, and an aeration port 23. The first outlet 12 is connected to the second inlet 21 through a liquid delivery pipe P1, and a first circulation pump is provided on the liquid delivery pipe P1. The second outlet 22 is connected to a drainage pipe and a first circulation pipe P2. A first exhaust port 13 and a second exhaust port 24 are respectively provided on the top of the anaerobic tank 1 and the aerobic tank 2.

[0069] The electrobiological oxidation adsorption unit includes an electrobiological phosphorus oxidation tank 3 and a baffled adsorption tank 4 arranged in parallel. The electrobiological phosphorus oxidation tank 3 is located above the anaerobic tank 1, and its bottom is connected to the interior of the anaerobic tank 1 through a first exhaust port 13. The baffled adsorption tank 4 is located above the aerobic tank 2, and its bottom is connected to the interior of the aerobic tank 2 through a second exhaust port 24.

[0070] The electrobiological phosphorus oxidation tank 3 is provided with a spray liquid inlet at the top and a third outlet 31 at the bottom. A reaction zone is provided between the spray liquid inlet and the third outlet 31. The reaction zone is provided with biological packing material 32 and electrodes 33. The biological packing material 32 is a porous packing material pre-inoculated with electroactive bacteria. The electrodes 33 are connected to an external power source. The spray liquid inlet is connected to a first circulation pipeline P2, and a second circulation pump is provided on the first circulation pipeline P2. The third outlet 31 is connected to a delivery pipeline P1 through a second circulation pipeline P3. A third exhaust port 34 is provided at the top of the electrobiological phosphorus oxidation tank 3.

[0071] The baffled adsorption tank 4 is equipped with adsorption packing 42 and vertical baffle 43, and a fourth exhaust port 41 is provided at the top.

[0072] The gas membrane separation unit 5 is located above the baffled adsorption tank 4. It is equipped with a gas separation membrane assembly 53 and is connected to the baffled adsorption tank 4 at the bottom through a fourth exhaust port 41. The gas membrane separation unit 5 is provided with an oxygen-enriched outlet 51 and a fifth exhaust port 52 at the top. The oxygen-enriched outlet 51 is connected to the aeration port 23, and an air pump is provided between the oxygen-enriched outlet 51 and the aeration port 23.

[0073] The phosphorus-containing wastewater treatment system provided in this embodiment of the invention has a three-layer structure, making full use of vertical space and the upward movement of gas, thus simplifying gas pipeline design. Specifically, the bottom layer is a biological phosphorus removal reaction unit, the middle layer is an electrobiological oxidation adsorption unit, and the top layer is a gas membrane separation unit 5. The biological phosphorus removal reaction unit is used to remove phosphorus from the wastewater. The electrobiological oxidation adsorption unit is located above the biological phosphorus removal reaction unit and is used to purify phosphine and bioaerosols generated during the liquid phosphorus removal process. The gas membrane separation unit 5 is used to further treat the purified gas, realizing the recycling of oxygen. At the same time, a portion of the liquid discharged from the aerobic tank 2 is returned to the electrobiological phosphorus oxidation tank 3 as a nutrient solution and conductive liquid. Therefore, this phosphorus-containing wastewater treatment system can perform biological phosphorus removal from phosphorus-containing wastewater while also treating the accompanying phosphine gas and bioaerosols, helping to eliminate safety hazards and protect the atmospheric environment. Furthermore, the entire system also achieves the reuse of oxygen and phosphorus resources.

[0074] The aforementioned biological phosphorus removal reactor includes an anaerobic tank 1 and an aerobic tank 2 arranged side-by-side. In the anaerobic tank 1, polyphosphate-accumulating bacteria (PABs) degrade organic matter in the wastewater using nucleoside triphosphates, releasing phosphorus accumulated within their cells. The organic matter in the wastewater provides the carbon source needed for the PPAs' respiration. Under anaerobic conditions, the PPAs utilize the organic matter in the wastewater for energy metabolism. Wastewater entering the anaerobic tank 1 comes into contact with the activated sludge, causing rapid conversion of the organic matter. In the aerobic tank 2, under aerobic conditions, PPAs fully absorb excess phosphorus, and then remove some of the phosphorus from the wastewater through the sludge discharge port 28, thus reducing the phosphorus content in the wastewater. To save space and simplify the structure of the biological phosphorus removal reactor, a partition can be installed within the microbial treatment tank to separate it into the anaerobic tank 1 and the aerobic tank 2.

[0075] The aforementioned anaerobic tank 1 is preferably an upflow anaerobic tank, meaning that the first inlet 11 of the first anaerobic tank 1 is located below the first outlet 12. Wastewater enters from the bottom of the anaerobic tank 1 and overflows from the top. This results in a much longer solids retention period and microbial retention period than the hydraulic retention period, thereby improving the decomposition rate of organic matter and the efficiency of the anaerobic zone. Please refer to [link / reference]. Figure 1 Preferably, the anaerobic tank 1 is provided with a first horizontal baffle 14 between the first inlet 11 and the first outlet 12. By setting the horizontal baffle, the water flow is guided into an upflow state, which helps to further improve the decomposition rate of organic matter and the reaction efficiency of the anaerobic tank. As a preferred embodiment, one end of the first horizontal baffle 14 is connected to the side wall of the anaerobic tank 1, and the other end has a gap of 50-100 mm between it and the opposite side wall. Phosphine gas generated in the anaerobic tank 1 during wastewater treatment enters the electrobiological phosphorus oxidation tank 3 through the first exhaust port 13 for waste gas treatment.

[0076] Wastewater discharged from anaerobic tank 1 is discharged through the first outlet 12 and then connected to the second inlet 21 of aerobic tank 2 via a liquid transfer pipeline P1 and a first circulation pump for further aerobic treatment. The aforementioned aerobic tank 2 is preferably an upflow anaerobic tank. Further, in the aerobic tank 2, the second outlet 22 is located above the aeration port 23, which is located above the first inlet 11; the aerobic tank 2 is equipped with an aeration pipe 25, a second horizontal baffle 26, and a membrane module 27. The aeration pipe 25 is connected to the aeration port 23, is arranged horizontally, and has a plurality of aeration holes evenly distributed on its surface for uniform aeration of the aerobic tank 2. The pore size of the aeration holes is preferably 2–45 mm. The second horizontal baffle 26 is disposed between the aeration pipe 25 and the second inlet 21. The second horizontal baffle 26 is positioned above the second inlet 21, guiding the water flow and extending the residence time of wastewater in the aerobic tank 2. The second horizontal baffle 26 is positioned below the aeration pipe 25 to prevent air / oxygen from the aeration pipe 25 from entering the anaerobic tank 1, thus maintaining the anaerobic state within the anaerobic tank 1. A sludge discharge port 28 is also provided at the bottom of the aerobic tank 2 for removing some phosphorus from the wastewater. In a preferred embodiment, one end of the second horizontal baffle 26 is connected to the side wall of the aerobic tank 2, and the other end has a gap of 50-100 mm between it and the opposite side wall. The membrane module 27 is disposed above the aeration pipe 25, and its outlet forms the second outlet 22. Those skilled in the art will understand that the inlet of the membrane module 27 is located above the aeration pipe 25. Membrane module 27 is used for solid-liquid separation, intercepting polyphosphate-accumulating bacteria in the aerobic tank 2 to prevent bacterial loss, and controlling suspended solids (SS) in the effluent, thus eliminating the need for a sedimentation tank. More preferably, the membrane module 27 is a hollow fiber membrane module, a flat sheet membrane module, a spiral wound membrane module, a tubular membrane module, or a pleated filter cartridge module. The membrane material can be a polyolefin membrane, a polyethylene membrane, a polyacrylonitrile membrane, a polysulfone membrane, or an aromatic polyamide membrane. Microbial aerosols generated during wastewater treatment in the aerobic tank 2 enter the baffled adsorption tank 4 for treatment through the second exhaust port 24.

[0077] The electrobiological oxidation and adsorption unit located in the second layer includes an electrobiological phosphorus oxidation tank 3 and a baffled adsorption tank 4 arranged in parallel, used to treat phosphine gas discharged from anaerobic tank 1 and microbial aerosol discharged from aerobic tank 2, respectively. Specifically:

[0078] Ordinary phosphine-oxidizing bacteria utilize oxygen to oxidize phosphine into phosphate. In this process, phosphine releases electrons, and oxygen absorbs them. The bottom of the electrobiological phosphine oxidation tank 3 is connected to the interior of the anaerobic tank 1 via the first exhaust port 13. Therefore, the oxygen content in this tank is low, making it difficult for ordinary phosphine-oxidizing bacteria to decompose phosphine. If oxygen is added to the tank, the anaerobic environment of the anaerobic tank 1 will be disrupted because the electrobiological phosphine oxidation tank 3 is connected to the anaerobic tank 1. To resolve this contradiction, this embodiment uses electroactive microorganisms to treat the phosphine gas. Electroactive microorganisms (such as Pseudomonas aeruginosa and Bacillus) are cultivated in the reaction zone of the electrobiological phosphine oxidation tank 3 through a biological filler 32. Under the stimulation of the energized electrodes, these electroactive microorganisms accumulate on and around the surface of the electrodes 33 and grow rapidly. These electroactive microorganisms have the ability to acquire electrons from outside their cells, resulting in a fast electron transfer rate and high phosphine conversion efficiency even under anaerobic conditions. To increase the content of electroactive microorganisms in the reaction zone, a biological packing material 32 and an electrode 33 are provided within the reaction zone. The biological packing material 32 is used to adsorb and support electroactive microorganisms, while the electrode 33, powered by an external power source, promotes the growth of electroactive microorganisms. The electroactive bacterial species pre-inoculated into the porous packing material are preferably one or two of *Pseudomonas aeruginosa* and *Bacillus*. To further optimize the removal effect of phosphine, the porous packing material is also preferably pre-inoculated with one or more of *Bacteroides*, *Methanogens*, *Chlorobacterium*, *Oligotrophomonas*, and *Pediococcus*. The electrode 33 is preferably a graphite electrode, a carbon felt electrode, or a carbon fiber electrode. The electrode 33 is arranged horizontally to increase the contact area between the gas and the microorganisms on the electrode 33.

[0079] The electrobiological phosphorus oxidation tank 3 is also equipped with a spray liquid inlet at its upper part. Water treated by the aerobic tank 2 is discharged through the second outlet 22 and divided into two parts: one part is discharged through a drain pipe, and the other part is connected to the spray liquid inlet through the first circulation pipe P2, contacting the reaction zone via spraying. This serves two purposes: firstly, the phosphates and other components in the liquid discharged from the aerobic tank 2 can serve as nutrients for the growth of microorganisms in the reaction zone, acting as a nutrient solution; secondly, for porous packing materials with poor conductivity, the conductivity of water can increase the electron conduction area in the reaction zone, which is beneficial for increasing the content of electroactive microorganisms. Preferably, the electrobiological phosphorus oxidation tank 3 is equipped with a spray pipe 35 connected to the spray liquid inlet; the spray pipe 35 has several sets of spray heads evenly arranged horizontally. The arrangement of these spray heads helps to achieve a more uniform distribution of the spray liquid in the reaction zone. Furthermore, each group is equipped with two spray heads, with the angle between each spray head and the vertical plane being 45° and the angle between the two spray heads being 90°.

[0080] The electrobiological phosphorus oxidation tank 3 is also equipped with a third outlet 31 at its lower part. Excess spray liquid and liquid formed by the microbial conversion of phosphine are discharged through the third outlet 31. The liquid discharged from the third outlet 31 contains a large number of microorganisms. Therefore, the third outlet 31 is connected to the liquid delivery pipeline P1 through the second circulation pipeline P3, and then enters the aerobic tank 2 for phosphorus removal treatment. The generated aerosol enters the baffled adsorption tank 4 for treatment. The working process of the electrobiological phosphorus oxidation tank 3 is roughly as follows: Phosphine gas entering the electrobiological phosphorus oxidation tank 3 from the first exhaust port 13 moves upward into the reaction zone, is oxidized by electroactive microorganisms, and is transferred from the gas phase to the liquid phase, converting into phosphate. The treated gas is discharged from the third exhaust port 34 at the top of the electrobiological phosphorus oxidation tank 3. The liquid phase is discharged from the third outlet 31 and enters the aerobic tank 2 through the second circulation pipeline P3 and the liquid delivery pipeline P1 for further treatment.

[0081] As a preferred embodiment, please refer to Figure 1 The electrobiological phosphorus oxidation tank 3 is equipped with a support plate 36, which is located above the third outlet 31. The biological packing material 32 is supported by the support plate 36, which has a plurality of evenly distributed air-guiding holes. The support plate 36 supports the biological packing material 32, and the air-guiding holes on it serve to evenly guide air. The phosphine-containing gas discharged from the first exhaust port 13 accumulates at the bottom of the electrobiological phosphorus oxidation tank 3 and is then evenly distributed through the support plate 36 before entering the reaction zone. Furthermore, the porous packing material is polyurethane, which has a large specific surface area and is lightweight. Therefore, it can adsorb more electroactive microorganisms while reducing the weight of the packing material and the load-bearing capacity of the support plate 36.

[0082] A baffled adsorption tank 4 is positioned above the aerobic tank 2, and its bottom is connected to the interior of the aerobic tank 2 via a second exhaust port 24. It is used to treat bioaerosols discharged from the aerobic tank 2. The baffled adsorption tank 4 contains adsorption packing material 42 and vertical baffles 43. Gas containing bioaerosols enters the baffled adsorption tank 4 through the second exhaust port 24 at the top of the aerobic tank 2. Under the guidance of the vertical baffles 43, the gas passes through the adsorption packing material 42 along the guiding path, and the bioaerosols are trapped in the adsorption packing material 42. The purified gas is discharged from the fourth exhaust port 41 at the top of the baffled adsorption tank 4. The vertical baffles 43 extend the residence time of the gas containing bioaerosols in the reactor, allowing for sufficient contact between the microbial aerosols and the adsorption packing material 42, thus improving the retention effect. Those skilled in the art will understand that the vertical baffles 43 are located between the second exhaust port 24 and the second exhaust port 24. Preferably, one end of the vertical baffle 43 is connected to the top or bottom surface of the baffle adsorption tank 4, and the other end has a gap of 50-100 mm between it and the opposite side. The horizontal distance between the two vertical baffles is 100-200 mm. The adsorption packing 42 is preferably activated carbon, ceramsite, diatomaceous earth, quartz sand, or molecular sieve. The particle size of the activated carbon, ceramsite, diatomaceous earth, or quartz sand is preferably 2-20 mm. In this embodiment, molecular sieve is preferably used. Molecular sieve releases a large amount of heat during the adsorption of bioaerosols, which inactivates the bacteria adsorbed on the molecular sieve. The analytical sieve is preferably a 4A molecular sieve or a 13X molecular sieve.

[0083] The gas membrane separation unit 5, located in the third layer, is used to further treat the purified gas discharged from the baffled adsorption tank 4 to achieve oxygen recycling. Specifically, the gas membrane separation unit 5 is located above the baffled adsorption tank 4, and its bottom is connected to the inside of the baffled adsorption tank 4 through the fourth exhaust port 41. It uses a gas separation membrane to achieve multi-component gas separation. Gas membrane separation technology separates gases under pressure by utilizing the adsorption capacity of each component in the gas on the surface of the polymer membrane and the difference in dissolution-diffusion rate within the membrane, i.e., the permeation rate difference. Generally, all gases can permeate the polymer membrane. The process involves gas molecules being adsorbed and dissolved on the high-pressure side of the membrane, then diffusing within the membrane due to the concentration gradient, and finally desorbing from the low-pressure side. The structure is such that small molecules and highly polar molecules pass through faster, while large molecules and less polar molecules pass through slower. Membrane separation oxygen generation technology uses air as a raw material. Under certain pressure conditions, air is passed through a membrane, and oxygen and nitrogen are separated by their different permeation rates within the membrane. The driving force for separation is the partial pressure difference of the gases across the membrane. Therefore, membrane gas separation does not involve phase change and does not require regeneration. Oxygen in the air permeates quickly, preferentially passing through the membrane and becoming enriched. Other gases permeate more slowly and remain largely on the feed air side, forming permeate gas. Driven by the pressure difference across the membrane, oxygen continuously permeates through the semi-permeable membrane to form oxygen-enriched air. The oxygen-enriched air is discharged from the oxygen-enriched outlet 51 and enters the aeration port 23 as supplementary oxygen for aeration. The remaining air is discharged from the fifth exhaust port 52. The gas separation membrane module 53 can be a flat-sheet membrane module, a spiral wound membrane module, or a hollow fiber membrane module. The membrane material of the gas separation membrane module 53 can be polysulfone, silicone rubber, or polyphenylene ether.

[0084] The overall workflow of the phosphorus-containing wastewater treatment system provided in this embodiment is as follows:

[0085] Wastewater treatment:

[0086] Phosphorus-containing wastewater enters the anaerobic tank 1 through the first inlet 11 for anaerobic treatment, and is discharged from the first outlet 12 after treatment;

[0087] Wastewater discharged from the first outlet 12 reaches the second inlet 21 of the aerobic tank 2 through the inlet pipeline P1, and enters the aerobic tank 2 for aerobic treatment; the generated aerosols enter the bottom of the baffle adsorption tank 4 through the second exhaust port 24. After treatment, the wastewater is discharged from the second outlet 22. Most of the water is discharged through the drain pipe, and a small portion of the water reaches the spray liquid inlet through the first circulation pipe P2, and flows from top to bottom through the reaction zone of the electrobiological phosphorus oxidation tank 3 as nutrient solution and conductive liquid; the liquid at the bottom of the electrobiological phosphorus oxidation tank 3 is discharged from the third outlet 31 and enters the inlet pipeline P1 through the second circulation pipe P3.

[0088] Phosphine waste gas treatment:

[0089] The waste generated in the anaerobic tank 1 enters the bottom of the electrobiological phosphorus oxidation tank 3 through the first exhaust port 13. During the upward movement, it comes into contact with the electroactive microorganisms in the reaction zone and is oxidized into liquid phosphorus by the electroactive microorganisms. The gas generated from the anaerobic tank 1 is purified and discharged from the third exhaust port 34 at the top of the electrobiological phosphorus oxidation tank 3.

[0090] Microbial aerosol treatment:

[0091] The aerosols generated in the aerobic tank 2 enter the baffled adsorption tank 4 through the second exhaust port 24. Under the guidance of the vertical baffle plate 43, the aerosols pass through the adsorption packing 42 along the guide path, and the bioaerosols are trapped in the adsorption packing 42, thus achieving the purification of microbial aerosols.

[0092] After purification, the gas is discharged from the fourth exhaust port 41 at the top of the baffled adsorption tank 4 and enters the gas membrane separation unit 5. After the gas is separated by the membrane module, the oxygen-rich gas is discharged from the oxygen-enriched outlet 51 and connected to the aeration port 23 to be used as supplementary oxygen for aeration. The remaining gas is discharged from the fifth exhaust port 52.

[0093] As can be seen from the above, the phosphorus-containing wastewater treatment system provided in this embodiment of the invention has the following advantages:

[0094] 1. The phosphorus-containing wastewater treatment system has a vertical three-layer structure, which makes full use of the vertical space and the characteristics of gas upward movement, simplifies the gas pipeline design, and reduces the equipment's footprint.

[0095] 2. This treatment system includes an electrobiological phosphorus oxidation tank and a baffled adsorption tank above the biological phosphorus removal reactor. These tanks are used to treat phosphine generated during anaerobic treatment and bioaerosol generated during aerobic treatment, respectively. Therefore, this phosphorus-containing wastewater treatment system can treat phosphine gas and bioaerosol generated simultaneously with the biological phosphorus removal from the wastewater, helping to eliminate safety hazards and protect the atmospheric environment.

[0096] 3. A portion of the liquid discharged from the aerobic tank of this treatment system is returned to the electrobiological phosphorus oxidation tank as nutrient solution and conductive liquid. The gas discharged from the baffled adsorption tank is separated and treated by a gas membrane separation unit, and the oxygen-enriched air is returned to the aerobic tank as supplementary aeration, saving energy. Therefore, this treatment system also achieves the reuse of oxygen and phosphorus resources.

[0097] The technical solution of the present invention will be further described below with reference to specific embodiments:

[0098] The phosphorus-containing wastewater treatment systems in the following embodiments have the same structure, such as... Figure 1As shown, from bottom to top, it includes: a biological phosphorus removal reaction unit, an electrobiological oxidation adsorption unit, and a gas membrane separation unit 5. The biological phosphorus removal reaction unit includes an anaerobic tank 1 and an aerobic tank 2 arranged side by side, separated by a partition. The anaerobic tank 1 includes: a first inlet 11, a first outlet 12, a first exhaust outlet 13, and a first horizontal baffle plate 14. The aerobic tank 2 includes: a second inlet 21, a second outlet 22, an aeration port 23, a second exhaust outlet 24, a sludge discharge port 28, an aeration pipe 25, a second horizontal baffle plate 26, and a membrane module 27. The specific structures of the anaerobic tank 1 and the aerobic tank 2 are the same as in the above embodiment, and the connection relationship between them is the same as in the above embodiment. The electrobiological oxidation adsorption unit includes an electrobiological phosphorus oxidation tank 3 and a baffle adsorption tank 4 arranged side by side, separated by a partition. The electrobiological phosphorus oxidation tank 3 includes: a spray liquid inlet, a third outlet 31, biological packing material 32, an electrode 33, a third exhaust port 34, a spray pipe 35, and a support plate 36; the baffle-type adsorption tank 4 includes: a fourth exhaust port 41, adsorption packing material 42, and a vertical baffle plate 43. The specific structures of the electrobiological phosphorus oxidation tank 3 and the baffle-type adsorption tank 4 are the same as in the above embodiments. The biological packing material 32 is a porous packing material pre-inoculated with Pseudomonas aeruginosa and Bacillus. The connection and positional relationship between the electrobiological phosphorus oxidation tank 3 and the anaerobic tank 1 and the aerobic tank 2, and the connection and positional relationship between the baffle-type adsorption tank 4 and the aerobic tank 2 are the same as in the above embodiments. The gas membrane separation unit 5 includes an oxygen-enriched outlet 51, a fifth exhaust port 52, and a gas separation membrane assembly 53, and its specific structure is the same as in the above embodiments. The positional relationship and connection relationship between the gas membrane separation unit 5 and the baffle-type adsorption tank 4 and the aerobic tank 2 are the same as in the above embodiments.

[0099] Example 1

[0100] Anaerobic tank:

[0101] Dimensions: Length, width, and height are 0.3m, 0.6m, and 0.5m respectively.

[0102] Hydraulic residence time: 10h

[0103] Aerobic tank:

[0104] Dimensions: Length, width, and height are 0.9m, 0.6m, and 0.5m respectively.

[0105] Hydraulic residence time: 10h

[0106] Aeration rate: 30L / min

[0107] Membrane module:

[0108] Hollow fiber membrane module; the membrane material is polyethylene membrane.

[0109] Electrobiological phosphorus oxidation pond:

[0110] Dimensions: Length, width, and height are 0.4m, 0.6m, and 0.3m respectively.

[0111] The porous filler is lightweight and porous polyurethane, and the anode and cathode electrode materials are carbon fiber.

[0112] Baffled adsorption tank:

[0113] Dimensions: Length, width, and height are 0.7m, 0.6m, and 0.15m respectively.

[0114] Adsorption packing material: 4A molecular sieve

[0115] Gas residence time: 2 min

[0116] Gas membrane separation unit:

[0117] Dimensions: Length, width, and height are 0.7m, 0.6m, and 0.15m respectively.

[0118] Gas separation membrane module: spiral wound membrane module, 3 sets in total; membrane material is polysulfone.

[0119] Membrane area: 0.15m² 2

[0120] The phosphorus-containing wastewater was treated using this phosphorus-containing wastewater treatment system, and the treatment results are as follows:

[0121] The initial concentrations of phosphorus, phosphine, and bacterial aerosols were 10.5 mg / L, 1.29 mg / m³, and 1.29 mg / m³, respectively. 3 642 CFU / m 3 After treatment, the concentrations were 0.30 mg / L and 0.03 mg / m³, respectively. 3 0 CFU / m 3 The removal rates reached 97.1%, 97.7%, and 100.0%, respectively. The concentration of total phosphorus emitted was lower than the national standards for pollutant discharge from urban wastewater treatment plants, and the concentration of bioaerosol emissions was lower than the national standards for indoor air quality.

[0122] Example 2

[0123] Anaerobic tank:

[0124] Dimensions: Length, width, and height are 1.5m, 3m, and 1.6m respectively.

[0125] Hydraulic residence time: 6 hours

[0126] Aerobic tank:

[0127] Dimensions: Length, width, and height are 4.5m, 3m, and 1.6m respectively.

[0128] Hydraulic residence time: 6 hours

[0129] Aeration rate: 140L / min

[0130] Membrane module:

[0131] Tubular membrane module; membrane material is polyethylene membrane.

[0132] Electrobiological phosphorus oxidation pond:

[0133] Dimensions: Length, width, and height are 3m, 3m, and 0.75m respectively.

[0134] The porous filler is granular activated carbon, and the anode and cathode electrode materials are carbon felt;

[0135] Baffled adsorption tank:

[0136] Dimensions: Length, width, and height are 3m, 3m, and 0.8m respectively.

[0137] Adsorption packing material: 4A molecular sieve

[0138] Gas residence time: 5 min

[0139] Gas membrane separation unit:

[0140] Dimensions: Length, width, and height are 3m, 3m, and 0.8m respectively.

[0141] Gas separation membrane module:

[0142] Spiral wound membrane module, the membrane material is silicone rubber.

[0143] Dimensions: Length, width, and height are 3m, 3m, and 0.8m respectively.

[0144] Membrane area: 3.5m² 2

[0145] The phosphorus-containing wastewater was treated using this phosphorus-containing wastewater treatment system, and the treatment results are as follows:

[0146] The initial concentrations of phosphorus, phosphine, and bacterial aerosol were 18.6 mg / L, 1.05 mg / m³, and 1.05 mg / m³, respectively. 3 1001 CFU / m 3 After treatment, the concentrations were 0.29 mg / L and 0.03 mg / m³, respectively. 3 75 CFU / m 3 The removal rates reached 98.4%, 97.1%, and 92.5%, respectively. The concentration of total phosphorus emitted was lower than the national standards for pollutant discharge from urban wastewater treatment plants, and the concentration of bioaerosol emissions was lower than the national standards for indoor air quality.

[0147] Example 3

[0148] Anaerobic tank:

[0149] Dimensions: Length, width, and height are 0.25m, 0.5m, and 0.6m respectively.

[0150] Hydraulic residence time: 8h

[0151] Aerobic tank:

[0152] Dimensions: Length, width, and height are 0.75m, 0.5m, and 0.6m respectively.

[0153] Hydraulic residence time: 8h

[0154] Aeration rate: 90L / min

[0155] Membrane module:

[0156] Flat sheet membrane module; the membrane material is polysulfone membrane.

[0157] Electrobiological phosphorus oxidation pond:

[0158] Dimensions: Length, width, and height are 0.4m, 0.5m, and 0.4m respectively.

[0159] The porous filler is lightweight and porous polyurethane, and the anode and cathode electrode materials are carbon rods;

[0160] Baffled adsorption tank:

[0161] Dimensions: Length, width, and height are 0.6m, 0.5m, and 0.3m respectively.

[0162] Adsorption packing material: 13X molecular sieve

[0163] Gas residence time: 1 min

[0164] Gas membrane separation unit:

[0165] Dimensions: Length, width, and height are 0.6m, 0.5m, and 0.1m respectively.

[0166] Gas separation membrane module:

[0167] Flat-panel membrane module; membrane material is polysulfone.

[0168] Membrane area: 0.2m² 2

[0169] The phosphorus-containing wastewater was treated using this phosphorus-containing wastewater treatment system, and the treatment results are as follows:

[0170] The initial concentrations of phosphorus, phosphine, bacterial aerosols, and fungal aerosols were 17.1 mg / L, 2.04 mg / m³, and 17.1 mg / L, 2.04 mg / m³, respectively. 3 530 CFU / m 3 284 CFU / m 3 After treatment, the concentrations were 0.9 mg / L and 0.04 mg / m³, respectively.3 4 CFU / m 3 6 CFU / m 3 The removal rates reached 94.7%, 98.0%, 99.2%, and 97.9%, respectively. The concentration of total phosphorus emitted was lower than the national standards for pollutant discharge from urban wastewater treatment plants, and the concentration of bioaerosol emissions was lower than the national standards for indoor air quality.

[0171] The various embodiments of the present invention have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or improvement of the technology in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

Claims

1. A phosphorus-containing wastewater treatment system, characterized in that, From bottom to top, it includes: a biological phosphorus removal reaction unit, an electrobiological oxidation adsorption unit, and a gas membrane separation unit; among which, The biological phosphorus removal reaction unit includes an anaerobic tank and an aerobic tank arranged in parallel. The anaerobic tank is provided with a first inlet and a first outlet, and the aerobic tank is provided with a second inlet, a second outlet, and an aeration port. The first outlet is connected to the second inlet via a liquid delivery pipeline, and a first circulation pump is installed on the liquid delivery pipeline. The second outlet is connected to a drainage pipeline and a first circulation pipeline. A first exhaust port and a second exhaust port are respectively provided on the top of the anaerobic tank and the aerobic tank. The electrobiological oxidation adsorption unit includes an electrobiological phosphorus oxidation tank and a baffled adsorption tank arranged in parallel; the electrobiological phosphorus oxidation tank is located above the anaerobic tank, and its bottom is connected to the interior of the anaerobic tank through a first exhaust port; the baffled adsorption tank is located above the aerobic tank, and its bottom is connected to the interior of the aerobic tank through a second exhaust port. The electrobiological phosphorus oxidation tank is equipped with a spray liquid inlet at the top and a third outlet at the bottom. A reaction zone is set between the spray liquid inlet and the third outlet, and biological packing material and electrodes are set in the reaction zone. The biological packing material is a porous packing material pre-inoculated with electroactive bacteria, and the electrodes are connected to an external power source. The spray liquid inlet is connected to a first circulation pipeline, and a second circulation pump is set on the first circulation pipeline. The third outlet is connected to a delivery pipeline through the second circulation pipeline. A third exhaust port is set at the top of the electrobiological phosphorus oxidation tank. The baffled adsorption tank is equipped with adsorption packing and vertical baffles, and a fourth exhaust port is provided at the top. The gas membrane separation unit is located above the baffled adsorption tank. It is equipped with a gas separation membrane assembly inside and is connected to the inside of the baffled adsorption tank through a fourth exhaust port at the bottom. The gas membrane separation unit is provided with an oxygen-enriched outlet and a fifth exhaust port at the top. The oxygen-enriched outlet is connected to the aeration port, and an air pump is provided between the oxygen-enriched outlet and the aeration port.

2. The phosphorus-containing wastewater treatment system according to claim 1, characterized in that, In the anaerobic tank, the first inlet is located below the first outlet; the anaerobic tank is provided with a first horizontal baffle between the first inlet and the first outlet.

3. The phosphorus-containing wastewater treatment system according to claim 1, characterized in that, In the aerobic tank, the second outlet is located above the aeration port, and the aeration port is located above the first inlet. The aerobic tank is equipped with an aeration pipe, a second horizontal baffle plate, and a membrane module. The aeration pipe is connected to the aeration port and is arranged horizontally with a plurality of aeration holes evenly distributed on its surface. The second horizontal baffle plate is located between the aeration pipe and the second inlet. The membrane module is located above the aeration pipe, and its outlet forms the second outlet. A sludge discharge port is also provided at the bottom of the aerobic tank.

4. The phosphorus-containing wastewater treatment system according to claim 3, characterized in that, The membrane module is a hollow fiber membrane module or a spiral wound membrane module.

5. The phosphorus-containing wastewater treatment system according to claim 1, characterized in that, The electrobiological phosphorus oxidation tank is equipped with a support plate located above the third outlet; the biological packing material is supported by the support plate, and the support plate is evenly provided with several air guide holes.

6. The phosphorus-containing wastewater treatment system according to claim 5, characterized in that, The porous filler is polyurethane.

7. The phosphorus-containing wastewater treatment system according to claim 1, characterized in that, The electrobiological phosphorus oxidation tank is equipped with a spray pipe, which is connected to the spray liquid inlet; the spray pipe is uniformly equipped with several sets of spray heads along the horizontal direction.

8. The phosphorus-containing wastewater treatment system according to claim 1, characterized in that, The electroactive bacterial species are one or two of Pseudomonas aeruginosa and Bacillus.

9. The phosphorus-containing wastewater treatment system according to claim 1, characterized in that, The electrode is a graphite electrode, a carbon felt electrode, or a carbon fiber electrode, and the electrode is arranged in a horizontal direction.

10. The phosphorus-containing wastewater treatment system according to claim 1, characterized in that, In the baffled adsorption tank, the adsorption packing material is activated carbon, ceramsite, diatomaceous earth, quartz sand, or molecular sieve.

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