A device for harmless treatment of sewage from passenger trains

Abstract

This invention provides a harmless treatment device for sewage from passenger trains. Influent and second internal recirculation effluent are fed into an anaerobic hydrolysis zone to form the first effluent, which is hydrolyzed into dissolved organic matter and small molecules, releasing phosphates. The first effluent and the first internal recirculation effluent are fed into anoxic zone I to form the second effluent. After denitrification in anoxic zone I, a portion is recirculated back to the anaerobic hydrolysis zone. The second effluent is fed into aerobic zone I to form the third effluent and the first internal recirculation effluent. Aeration is applied to aerobic zone I to complete the nitrification of ammonia nitrogen and the removal of carbonaceous organic matter from the influent. The third effluent is fed into anoxic zone II to form the fourth effluent, which undergoes denitrification. The fourth effluent is fed into aerobic zone II to form sludge and the fifth effluent. The sludge enters a sludge storage zone, where deep nitrification and phosphorus removal are carried out. This invention is simple in structure, low in cost, and easy to operate, and can treat existing high-concentration sewage from passenger trains.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment and is a device for treating high-concentration sewage. Background Technology

[0002] With the rapid development of railways, more and more large stations, train depots and stations are being put into use. Nowadays, all newly manufactured ordinary trains, bullet trains and high-speed trains are equipped with toilet systems to prevent environmental pollution caused by direct discharge of sewage. In large stations, bullet train depots, stations or passenger car maintenance depots, sewage from the toilets is vacuumed to the ground sewage receiving system.

[0003] Wastewater collected from the feces falls under the category of domestic sewage, but it differs significantly from conventional domestic sewage. It is characterized by "four highs and one low," namely, high organic matter, high suspended solids (SS), high ammonia nitrogen, high phosphorus, and low carbon-to-nitrogen ratio. The high ammonia nitrogen and low carbon-to-nitrogen ratio are particularly prominent. Some literature indicates that high ammonia nitrogen in the influent significantly inhibits microbial activity, and the ammonia nitrogen removal rate needs to reach about 95%, requiring targeted treatment.

[0004] The related technologies involve numerous sewage treatment processes, dividing the treatment of sewage into multiple steps that require multiple people to operate simultaneously, making them unsuitable for railway stations. Alternatively, the sewage treatment systems are quite complex and have stringent environmental requirements, hindering their large-scale application in railway stations.

[0005] Currently, the general practice for treating sewage from railway stations is to first perform anaerobic biological pretreatment before mixing it with other sewage from railway stations or depots and discharging it into the municipal sewage system. This is contingent on the sewage's proportion in the total volume not being too high. However, railway sewage discharge fluctuates significantly. While office and domestic wastewater discharge from railway stations is concentrated during the day, sewage from train maintenance is mostly discharged at night. Therefore, even if the volume of other wastewater from stations is much greater than the volume of sewage from trains, and theoretical calculations suggest that the total discharge outlet can meet standards after mixing, the uneven timing of sewage discharge from trains often results in water quality indicators exceeding standards at certain times during actual monitoring. With the full implementation of the wastewater discharge permit system, both water quality and quantity are controlled at the main sewage outlets of newly constructed projects connected to the municipal system, and strict management is achieved through real-time monitoring and other technical means. Ensuring that treated sewage meets discharge standards is a key focus and challenge for relevant departments. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the purpose of this invention is to provide a harmless treatment device for sewage from passenger trains, which is simple in structure, low in cost and easy to operate, and can treat the existing high-concentration sewage from passenger trains.

[0007] To solve the above technical problems, the technical solution adopted by the present invention is as follows:

[0008] A harmless treatment device for the centralized night soil sewage of passenger trains, comprising an anaerobic hydrolysis zone, an anoxic zone I, an aerobic zone I, an anoxic zone II, an aerobic zone II and a sludge storage zone arranged in sequence. The influent water and the second internal recycled effluent are input into the anaerobic hydrolysis zone to form the first effluent. The anaerobic hydrolysis zone uses anaerobic or facultative bacteria to hydrolyze the suspended solids and macromolecular substances that are difficult to biodegradable in the sewage into soluble organic substances and easily biodegradable small molecular substances, and releases phosphate under anaerobic conditions. The first effluent and the first internal recycled effluent are input into the anoxic zone I to form the second effluent. After the first denitrification and nitrogen removal in the anoxic zone I, a part is refluxed to the anaerobic hydrolysis zone to ensure the sludge concentration in the anaerobic hydrolysis zone. The second effluent and the sludge reflux of the aerobic zone II are returned to the aerobic zone I to form the third effluent and the first internal recycled effluent. Aeration is carried out in the aerobic zone I to complete the nitrification reaction of the influent ammonia nitrogen and the removal of carbonaceous organic matter. The third effluent is input into the anoxic zone II to form the fourth effluent. The second denitrification and nitrogen removal is carried out in the anoxic zone II. The fourth effluent is input into the aerobic zone II to form sludge and the fifth effluent. The sludge enters the sludge storage zone, and the aerobic zone II carries out a deep nitrification reaction and the main phosphorus removal reaction.

[0009] Further, the first internal recycled effluent and the second internal recycled effluent are lifted and refluxed by a water pump.

[0010] Further, submersible agitators are arranged in the anaerobic hydrolysis zone, the anoxic zone I and the anoxic zone II.

[0011] Further, an external carbon source is appropriately added to the anoxic zone I according to the concentration of the first effluent to ensure the complete denitrification reaction.

[0012] Further, the aerobic zone I has a "C" - shaped structure and includes a first tank body, a second tank body and a third tank body connected in sequence. A first inlet is provided on the first tank body, and a first outlet is provided on the third tank body. The second effluent enters the first tank body from the anoxic zone I through the first inlet, and the third effluent is discharged from the third tank body through the first outlet to the third tank body.

[0013] Further, the anaerobic hydrolysis zone is a mixed liquid composed of sewage and biological sludge. Aeration is carried out in the aerobic zone I and the aerobic zone II. A carbon source is appropriately added in the anoxic zone I and the anoxic zone II. A chemical phosphorus removal agent is added in the aerobic zone II. The chemical phosphorus removal agent is PAC, ferric sulfate or aluminum sulfate.

[0014] Further, the carbon source is added by a dosing pump.

[0015] Further, submersible agitators are arranged in the anaerobic hydrolysis zone, the anoxic zone I and the anoxic zone II.

[0016] Furthermore, the aerobic I zone contains suspended packing material.

[0017] Furthermore, an immersion membrane module is installed in the aerobic II zone.

[0018] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0019] This invention proposes a high-concentration sewage treatment system that is simple in structure, low in cost, and easy to operate, enabling it to adapt to different working environments and achieve good treatment results. Conventional processes generally employ anaerobic / anoxic / aerobic processes, while this invention adds an anoxic and aerobic stage, i.e., anaerobic / anoxic / aerobic / anoxic / aerobic, and integrates the advantages of both MBBR and MBR processes, ensuring the quality of the effluent.

[0020] This invention employs a reasonable and effective method to promote the exchange of activated sludge throughout the system, enhances the treatment effect of each unit for various effluent indicators, improves treatment efficiency, is easy to control, and ensures the stability of the biochemical treatment system.

[0021] The ammonia nitrogen removal rate of this invention is approximately 95%, exceeding the normal primary treatment rate of approximately 80%, requiring a two-stage reactor in series operation. Integrating the wastewater treatment process in series allows for modular assembly, facilitating transportation and installation. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and are intended to explain the invention, but do not constitute an undue limitation thereof. In the drawings:

[0023] Figure 1 This is a planar schematic diagram of the present invention;

[0024] Figure 2 This is a schematic diagram of the process of the present invention;

[0025] Figure 3 This is a schematic diagram of the immersion membrane module of the present invention.

[0026] Among them: 1. Anaerobic hydrolysis zone; 2. Anoxic zone I; 3. Aerobic zone I; 4. Anoxic zone II; 5. Aerobic zone II; 6. Sludge storage zone; 7. First internal reflux effluent; 8. Second internal reflux effluent. Detailed Implementation

[0027] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] This invention provides a device for the harmless treatment of sewage from passenger trains, such as... Figure 1 and Figure 2 As shown, the system includes, in sequence, an anaerobic hydrolysis zone 1, an anoxic zone I 2, an aerobic zone I 3, anoxic zone II 4, aerobic zone II 5, and a sludge storage zone 6. Influent and the second internal recirculation effluent 8 are input into the anaerobic hydrolysis zone 1 to form the first effluent. The anaerobic hydrolysis zone 1 utilizes anaerobic or facultative bacteria to hydrolyze suspended solids and recalcitrant macromolecules in the wastewater into dissolved organic matter and readily biodegradable small molecules, releasing phosphates under anaerobic conditions. The first effluent and the first internal recirculation effluent 7 are input into the anoxic zone I 2 to form the second effluent. The anoxic zone I 2 undergoes the first denitrification process. Nitrogen is partially recycled to anaerobic hydrolysis zone 1 to ensure sludge concentration in anaerobic hydrolysis zone 1. The second effluent and sludge from aerobic zone II 5 are recycled to aerobic zone I 3 to form the third effluent and the first internal recycled effluent 7. Aerobic zone I 3 is aerated to complete the nitrification reaction of influent ammonia nitrogen and the removal of carbonaceous organic matter. The third effluent is fed into anoxic zone II 4 to form the fourth effluent. Anoxic zone II 4 undergoes a second denitrification to remove nitrogen. The fourth effluent is fed into aerobic zone II 5 to form sludge and the fifth effluent. The sludge enters sludge storage zone 6. Aerobic zone II 5 undergoes deep nitrification and phosphorus removal.

[0030] This invention proposes a high-concentration sewage treatment system that is simple in structure, low in cost, and easy to operate, enabling it to adapt to different working environments and achieve good treatment results. Conventional processes generally employ anaerobic / anoxic / aerobic processes, while this invention adds an anoxic and aerobic stage, i.e., anaerobic / anoxic / aerobic / anoxic / aerobic, and integrates the advantages of both MBBR and MBR processes, ensuring the quality of the effluent.

[0031] This invention employs a reasonable and effective method to promote the exchange of activated sludge throughout the system, enhances the treatment effect of each unit for various effluent indicators, improves treatment efficiency, is easy to control, and ensures the stability of the biochemical treatment system.

[0032] The ammonia nitrogen removal rate of this invention is approximately 95%, exceeding the normal primary treatment rate of approximately 80%, requiring a two-stage reactor in series operation. Integrating the wastewater treatment process in series allows for modular assembly, facilitating transportation and installation.

[0033] In this invention, the main function of anaerobic hydrolysis zone 1 is to utilize anaerobic or facultative bacteria to hydrolyze suspended solids and recalcitrant macromolecules in wastewater into soluble organic matter and readily biodegradable small molecules, releasing phosphates under anaerobic conditions. Anaerobic hydrolysis zone 1 contains a mixed liquor composed of wastewater and biological sludge. The influent and the mixed liquor from anoxic zone I 2 are mixed in the anaerobic tank. A submersible mixer is installed in anaerobic hydrolysis zone 1, located in a hole in the partition wall between anaerobic hydrolysis zone 1 and anoxic zone I 2. The submersible mixer propels the circulating flow of the mixed liquor, thus solving the problems of low flow velocity at the bottom of the tank and sludge deposition during return flow. The second internal return effluent 8 is pumped back, and the return effluent is also thoroughly mixed with the influent through the mixer. The purpose of the return effluent is to maintain the sludge concentration in the anaerobic tank, allowing polyphosphate-accumulating bacteria to absorb and store low-molecular-weight organic matter while releasing phosphates.

[0034] In this invention, the first internal reflux effluent 7 is pumped back, and the reflux is also fully mixed with the influent through a stirrer. The purpose of the reflux is to maintain the sludge concentration in the anaerobic tank.

[0035] In this invention, the anoxic zone I 2 is the main denitrification reaction zone. The effluent from the anaerobic hydrolysis zone 1 merges with the first internal return effluent 7 from the aerobic zone I 3, and denitrification is completed within the anoxic zone I 2. A portion of the mixed liquor forms the first internal return effluent I and is returned to the anaerobic hydrolysis zone 1 to ensure the sludge concentration in the anaerobic hydrolysis zone 1. A submersible mixer is installed in the anoxic zone I 2 to propel the circulation of the mixed liquor, thereby solving the problems of low flow velocity at the bottom of the tank and sludge deposition during return. An external carbon source is added appropriately according to the influent concentration to ensure complete denitrification. The external carbon source is added using a dosing pump, and the specific dosage is determined during commissioning. The flow rate of the dosing pump is adjustable.

[0036] In the present invention, the aerobic zone I 3 is the main nitrification reaction zone. After the effluent from the anoxic zone I 2 and the returned sludge from the aerobic zone II 5 converge, the nitrification reaction of the influent ammonia nitrogen and the removal of carbonaceous organic matter are completed in the aerobic zone I 3, and a part of the mixed liquor is returned to the anoxic zone to ensure the sludge concentration in the anoxic zone. There are suspended fillers in the reaction zone, which greatly increases the total amount of organisms in the pool, is beneficial to the treatment of high-concentration sewage, strengthens the nitrification reaction, and reduces the reactor volume. The reaction zone is in a circulating folded-flow type. The sewage undergoes one cycle and basically eliminates short-circuit flow. When the sewage flows in the pool, it is in a plug-flow state within one cycle and in a mixed state within multiple cycles, with the characteristics of both plug flow and complete mixing, which is beneficial to overcoming short-circuit flow and improving the buffering capacity. The density of the suspended fillers is close to that of water, they are finished products, and the filling rate is not higher than 50%.

[0037] In the present invention, the effluent of the first internal return flow 7 is lifted and returned by a water pump, and the nitrate nitrogen required for denitrification is provided.

[0038] In the present invention, the aerobic zone I 3 has a "匚"-shaped structure and includes a first pool body, a second pool body, and a third pool body that are connected in sequence. A first inlet is provided on the first pool body, and a first outlet is provided on the third pool body. The second effluent enters the first pool body from the anoxic zone I 2 through the first inlet, and the third effluent is discharged from the third pool body to the third pool body through the first outlet, so that the aerobic zone I 3 forms a circulating folded-flow type, greatly increasing the total amount of organisms in the pool, being beneficial to the treatment of high-concentration sewage, strengthening the nitrification reaction, and reducing the reactor volume. The sewage undergoes one cycle and basically eliminates short-circuit flow. When the sewage flows in the pool, it is in a plug-flow state within one cycle and in a mixed state within multiple cycles, with the characteristics of both plug flow and complete mixing, which is beneficial to overcoming short-circuit flow and improving the buffering capacity.

[0039] As Figure 1 shown, the anaerobic hydrolysis zone 1, the anoxic zone I 2, and the first pool body are arranged in a row, and the third pool body, the anoxic zone II 4, the aerobic zone II 5, and the sludge storage zone 6 are arranged in a row. The second pool body connects the first pool body and the third pool body, does not occupy space, has a compact structure, and can ensure complete sewage reaction.

[0040] In the present invention, the anoxic zone II 4 is the deep denitrification zone. After the effluent from the aerobic zone I 3 and the externally added carbon source converge, further denitrification and nitrogen removal are completed in the anoxic zone II 4, reducing the nitrate nitrogen index and the total nitrogen index of the effluent. A submersible mixer is arranged in the anoxic zone II 4 to promote the circulating flow of the mixed liquor, thereby solving the problems of low flow velocity at the bottom of the pool and deposition of returned sludge. The anoxic zone II 4 can also utilize the endogenous carbon source of microorganisms to complete further denitrification to strengthen nitrogen removal, which can save the externally added carbon source, reduce the sludge production rate, and reduce the sludge treatment cost.

[0041] In this invention, aerobic zone II 5 is a deep nitrification zone and the main phosphorus removal reaction zone. The effluent from anoxic zone II 4 completes the deep ammonia nitrogen nitrification reaction and carbonaceous organic matter removal in aerobic zone I 3. This removes the microbubbles generated in anoxic zone II 4 and attached to the sludge flocs, as well as the ammonia nitrogen released during sludge retention, thus preventing the release of phosphates from the sludge into the final effluent. At the same time, chemical phosphorus removal agents are added to ensure that the total nitrogen, ammonia nitrogen, and total phosphorus in the effluent meet the standards. Part of the mixed liquor is recycled back to aerobic zone I 3 to ensure its activated sludge concentration, and the remaining sludge is discharged to the sludge storage tank.

[0042] In this invention, such as Figure 3 As shown, a submerged membrane module is installed in aerobic zone II 5. The high efficiency of the membrane separation ensures that the microorganisms are completely trapped in the bioreactor, maintaining a high concentration of microorganisms in the system. This not only improves the overall removal efficiency of pollutants by the reactor and ensures good effluent quality, but also makes the reactor highly adaptable to the influent load, ensuring that the effluent meets the standards stably.

[0043] In this invention, aerobic zone I 3 and aerobic zone II 5 are oxygenated by aeration pipes (the dissolved oxygen concentration DO in the aerobic zone is controlled, with DO in aerobic zone I 3 at 2.0 mg / L and DO in aerobic zone II 5 at 2.5-3.0 mg / L; the oxygenation is done by filling with air, using the oxygen in the air to ensure the activity of microorganisms) in order to maintain the activity of microorganisms.

[0044] In this invention, the sludge storage area 6 is used to store the residual sludge generated by the system. It can be concentrated and dehydrated to make ecological fertilizer for further resource utilization, such as for landscaping.

[0045] The complete set of equipment can be installed in a fully buried, semi-buried, or non-buried manner depending on the site conditions. It can be made of carbon steel, fiberglass, or reinforced concrete.

[0046] In addition to treating sewage from passenger trains, this device is also suitable for the harmless treatment of sewage from airports, urban and rural public toilets, and other facilities.

[0047] Anaerobic hydrolysis zone 1 is a mixed liquor composed of sewage and biological sludge. It is aerated in aerobic zone I 3 and aerobic zone II 5. An appropriate amount of carbon source is added in anoxic zone I 2 and anoxic zone II 4. Chemical phosphorus removal agent is added in aerobic zone II 5. The chemical phosphorus removal agent is PAC, ferric sulfate or aluminum sulfate.

[0048] The carbon source is added using a dosing pump.

[0049] In summary, this invention is functionally divided into anaerobic hydrolysis zone 1, anoxic zone I 2, aerobic zone I 3, anoxic zone II 4, aerobic zone II 5, and sludge storage zone 6. Each reaction zone is independent, which is conducive to the efficient removal of pollutants such as COD, total nitrogen, ammonia nitrogen, and total phosphorus.

[0050] In this invention, submersible mixers are installed in the anaerobic hydrolysis zone 1 and the anoxic zone to promote the circulation of the mixed liquid, thereby solving the problems of low flow velocity at the bottom of the tank and sedimentation of refluxed sludge.

[0051] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. A device for harmless treatment of sewage collected from passenger trains, characterized in that: It includes an anaerobic hydrolysis zone, an anoxic I zone, an aerobic I zone, an anoxic II zone, an aerobic II zone and a sludge storage zone arranged in sequence. The influent and the effluent of the second internal reflux are input into the anaerobic hydrolysis zone to form the first effluent. The anaerobic hydrolysis zone uses anaerobic or facultative bacteria to hydrolyze the suspended solids and macromolecular substances that are difficult to biodegradate in the sewage into soluble organic substances and easily biodegradable small molecular substances, and releases phosphate under anaerobic conditions; The first effluent and the effluent of the first internal reflux are input into the anoxic I zone to form the second effluent. After the first denitrification and nitrogen removal in the anoxic I zone, a part is refluxed to the anaerobic hydrolysis zone to ensure the sludge concentration in the anaerobic hydrolysis zone. The second effluent and the sludge reflux of the aerobic II are returned to the aerobic I zone to form the third effluent and the effluent of the first internal reflux. Aeration is carried out in the aerobic I zone to complete the nitrification reaction of the influent ammonia nitrogen and the removal of carbonaceous organic substances. The third effluent is input into the anoxic II zone to form the fourth effluent. The second denitrification and nitrogen removal are carried out in the anoxic II zone. The fourth effluent is input into the aerobic II zone to form sludge and the fifth effluent. The sludge enters the sludge storage zone. The aerobic II zone carries out deep nitrification reaction and the main phosphorus removal reaction; The aerobic I zone has a "匚" - shaped structure and includes a first tank body, a second tank body and a third tank body connected in sequence. A first inlet is provided on the first tank body, and a first outlet is provided on the third tank body. The second effluent enters the first tank body from the anoxic I zone through the first inlet, and the third effluent is discharged from the third tank body to the anoxic II zone through the first outlet; There are suspended fillers in the aerobic I zone; Submerged membrane modules are installed in the aerobic II zone; The effluent of the first internal reflux and the effluent of the second internal reflux are lifted and refluxed by a water pump; The anaerobic hydrolysis zone is a mixed liquid composed of sewage and biological sludge. Aeration is carried out in the aerobic I zone and the aerobic II zone. A carbon source is appropriately added in the anoxic I zone and the anoxic II zone, and a chemical phosphorus removal agent is added in the aerobic II zone. The chemical phosphorus removal agent is PAC, ferric sulfate or aluminum sulfate.

2. The passenger train sewage treatment device according to claim 1, characterized in that: Submersible agitators are installed in the anaerobic hydrolysis zone, the anoxic I zone and the anoxic II zone.

3. The passenger train sewage treatment device according to claim 1, characterized in that: The anoxic I zone appropriately adds an external carbon source according to the concentration of the first effluent to ensure the complete denitrification reaction.

4. The passenger train sewage treatment device according to claim 1, characterized in that: The carbon source is added by a dosing pump.

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