Integrated system and method for nitrogen and phosphorus removal of high-speed train source separation urine

Abstract

The invention provides an integrated system and method for nitrogen and phosphorus removal of high-speed train source separation urine. The system comprises a source separation closestool and a coaxial integrated three-stage reactor which are connected with each other, the source separation closestool is used for separating excrement and urine from the source and conveying the separated urine to the coaxial integrated three-stage reactor; the coaxial integrated three-stage reactor comprises an inner layer, a transition area a, a middle layer, a transition area b and an outer layer which are sequentially connected from inside to outside; wherein sponge filler inoculated with microorganisms is arranged in the inner layer; the top of the inner layer is provided with a connecting port communicated with the transition area a; a connecting port communicated with the middle layer is formed in the bottom of the transition area a, an MABR membrane assembly is arranged in the middle layer, and the middle layer is further connected with an air blower; the top of the middle layer is provided with a connecting port communicated with the transition area b; a connecting port communicated with the outer layer is formed in the bottom of the transition area b, and a filter element filled with a dephosphorization adsorbent is arranged in the outer layer.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to an integrated system and method for denitrification and dephosphorization of urine separated from sources on high-speed trains. Background Art

[0002] In order to reduce the emission of pollutants during railway transportation, the traditional direct discharge excrement treatment method has been replaced by the collection of toilets. However, the sewage from the high-speed railway collection of toilets has the potential risk of high pollution and high biological toxicity. This type of wastewater shows high COD, high SS, high NH 4+ -N, high P, high biological toxicity and low C / N.

[0003] The current method for treating wastewater from high-speed train toilets is a typical, energy-intensive, end-of-pipe treatment model for pollutants. Typically, after being collected and discharged through various unloading methods, wastewater from toilets on trains is discharged into the sewage treatment systems of various stations, where it mixes with some domestic sewage and car wash wastewater. This significantly increases pollutant concentrations. Even with simple treatment in existing, outdated sewage treatment facilities, the effluent is difficult to meet pipe requirements. However, the existing sewage tanks occupy up to 450 liters of space, adding to the high-speed train's load capacity. Furthermore, additional water is required to hydrolyze urea, which consumes a significant amount of water. Volatile substances such as ammonia produced by urine hydrolysis have a pungent odor and can easily have adverse effects on the environment.

[0004] Therefore, conducting integrated research on the high-quality in-situ resource reuse mechanism and key technologies for on-board collected fecal wastewater and realizing the important transformation from on-board sewage collectors to in-situ resource generators has important practical significance for the development of green high-speed rail. Summary of the Invention

[0005] In order to solve the above technical problems, the present invention provides an integrated system and method for denitrification and dephosphorization of urine separated from sources on high-speed trains.

[0006] To achieve the above object, the technical solution adopted by the present invention is as follows:

[0007] The present invention provides an integrated system for source separation urine denitrification and phosphorus removal on high-speed trains, the system comprising: a connected source separation toilet and a coaxial integrated three-stage reactor; the source separation toilet is used to separate feces and urine at the source, and transport the separated urine to the coaxial integrated three-stage reactor; the coaxial integrated three-stage reactor comprises an inner layer, a transition zone a, a middle layer, a transition zone b and an outer layer connected in sequence from the inside to the outside; wherein a water inlet is provided on the inner layer, the water inlet is used to transport the separated urine to the inner layer, and a sponge filler inoculated with microorganisms is provided in the inner layer material; the top of the inner layer is provided with a connection port connected to the transition zone a; the bottom of the transition zone a is provided with a connection port connected to the middle layer, the middle layer is provided with an MABR membrane assembly, and the middle layer is also connected to a blower; the top of the middle layer is provided with a connection port connected to the transition zone b; the bottom of the transition zone b is provided with a connection port connected to the outer layer, the outer layer is provided with a filter element filled with a phosphorus removal adsorbent; the outer layer is provided with a water outlet, which is used to return part of the treated urine to the water inlet and transport the other part to the source separation toilet for flushing.

[0008] Furthermore, the phosphorus removal adsorbent is specifically a granular FeOOH-biochar composite material.

[0009] Furthermore, the transition zone a and the transition zone b are both provided with activated carbon, which is used to remove odor and pigments in urine to further improve the water quality of the effluent, thereby meeting other water needs of the high-speed train.

[0010] Furthermore, a source separation urine storage tank is provided between the source separation toilet and the coaxial integrated three-stage reactor, and the source separation urine storage tank is used to store the separated urine and transport the separated urine to the water inlet.

[0011] Furthermore, a water inlet pump and a liquid flow meter a are sequentially arranged between the source separated urine storage tank and the water inlet.

[0012] Furthermore, a water production tank is provided between the coaxial integrated three-stage reactor and the source separation toilet. An ultraviolet lamp is provided in the water production tank, and the water production tank is used to perform ultraviolet disinfection on the treated urine discharged from the water outlet.

[0013] Furthermore, a reflux pump and a liquid flow meter b are sequentially arranged between the water outlet and the water inlet; and an air flow meter is also arranged between the blower and the middle layer.

[0014] The present invention provides a method for denitrification and phosphorus removal of urine separated from a high-speed train source, which is applied to the above-mentioned integrated system for denitrification and phosphorus removal of urine separated from a high-speed train source; the method comprises:

[0015] First, urine is separated by a source separation toilet and fed into the inner layer through the water inlet. Microorganisms inoculated in the sponge packing hydrolyze the urea in the urine into ammonia nitrogen, while denitrification removes organic matter and refluxed nitrate nitrogen. It should be noted that the inner layer is an anaerobic environment. The urea contained in the urine is hydrolyzed into ammonia nitrogen by the urease-producing microorganisms attached to the sponge packing. The sponge packing does not cause clogging of the device and has a certain ability to control the urine flow. At the same time, denitrifying bacteria in the inner layer carry out denitrification reactions, removing nitrate nitrogen that flows back into the inner layer and COD in the urine.

[0016] The urine then passes through transition zone a and enters the middle layer, where MABR membrane modules undergo integrated partial nitritation / anaerobic ammonium oxidation (ANAMMOX) denitrification. It should be noted that urine from transition zone a enters the middle layer, where it undergoes integrated partial nitritation / ANAMMOX reactions, converting ammonia nitrogen into nitrogen gas and a small amount of nitrate. The MABR modules provide targeted nourishment for nitrite-destroying bacteria, reducing power consumption and maintaining low oxygen levels in other areas to facilitate the overall reaction. The treated urine then enters transition zone b. The process in transition zone b is similar to that in transition zone a, extending the hydraulic retention time of the urine in the outer layer to further remove odor and pigments.

[0017] After passing through the transition zone b, it enters the outer layer and removes phosphates through the adsorption of the phosphorus removal adsorbent to achieve phosphorus removal from urine. In the present invention, the phosphorus removal adsorbent is preferably a FeOOH-biochar composite material. The urine in the transition zone b enters the outer layer and passes through the filter element filled with granular FeOOH-biochar composite material. The FeOOH-biochar composite material uses amorphous FeOOH and has a large specific surface area (398.66m 2 ·g -1 ), combined with biochar generated from recyclable materials such as corn straw. It is resource-friendly and has a high adsorption capacity for phosphates. The adsorption effect is best in a weakly acidic environment, and phosphorus removal can be achieved by simply controlling the pH. After phosphorus removal in the outer layer, part of the urine flows back to the inner layer for deep denitrification and phosphorus removal. Moreover, the phosphorus adsorption rate of the FeOOH-biochar composite material only decreases by 5.1% to 5.7% after three reuses. The recovered phosphate and the FeOOH-biochar composite material that cannot be reused after adsorption saturation can be used to prepare slow-release phosphate fertilizer, which is economical.

[0018] Finally, the treated urine is discharged from the outlet, part of which is refluxed for further denitrification and phosphorus removal, and the other part is used to flush the source separation toilet.

[0019] Furthermore, the air flow rate of the MABR in the middle layer is adjusted to keep the dissolved oxygen (DO) in the upper layer at 0.3-0.5 mg / L, while the dissolved oxygen in the inner layer is 0. As a result, the hydrolysis rate of urea in fresh urine by the anaerobic bacteria in the inner layer is above 85%.

[0020] Furthermore, the hydraulic retention time of the inner layer and the middle layer is 2 to 3 hours; the hydraulic retention time of the outer layer is 2 to 3 hours.

[0021] It should be noted that activated carbon filters can be installed in both transition zones a and b to remove odors and pigments, further improving the effluent quality and meeting other water needs of high-speed trains. The urine treated in the inner layer passes through transition zone a, where the activated carbon loaded can be used to adsorb and remove volatile nitrogen-containing compounds (such as ammonia, amines) and short-chain fatty acids in the urine, reducing the intensity of the odor; as well as adsorbing natural pigments (such as urobilin) ​​and other colored impurities in the urine, improving the color of the liquid and making it clearer in appearance. The two transition zones extend the hydraulic retention time of urine in the middle and outer layers, further accurately controlling the efficient conduct of each reaction.

[0022] Compared with the existing technology, the technical solution provided by the present invention has at least the following advantages:

[0023] The present invention provides an integrated system and method for denitrification and phosphorus removal of urine separated from high-speed train sources. The system uses a coaxial integrated three-stage reactor independently developed by the system. Denitrification sponge filler is used in the inner layer to remove organic matter in urine, reducing its adverse effects on subsequent production. Urea hydrolyzing bacteria are used to convert urea into ammonia nitrogen. The refluxed nitrate nitrogen is combined with COD to convert into nitrogen gas to achieve deep denitrification. The middle layer uses MABR membrane components. Aerobic ammonia oxidizing bacteria convert ammonia nitrogen into nitrite, and anaerobic ammonia oxidizing bacteria directly convert nitrite into nitrogen gas to achieve autotrophic denitrification. In addition, MABR can not only increase the aeration volume and reduce operating costs, but also reduce the volatilization of volatile gases in urine and reduce adverse effects on the outside world. In the outer layer, FeOOH-biochar composite material is used for phosphorus removal. The phosphorus removal effect is stable and the cost is low. It can adsorb phosphates in sewage onto its surface. The material after adsorption saturation can be used as a slow-release phosphate fertilizer. Compared to current train sewage collection tanks, this system boasts a reduced overall volume. The coaxial, integrated three-stage reactor design saves 57% space compared to traditional multi-stage treatment units, making it more suitable for the confined environments of high-speed rail systems. Calculations show that the optimized wastewater recovery and treatment system's overall volume has been reduced to less than 200L, a reduction of over 55%. This saved space allows for the installation of other train equipment and the storage of more treated greywater for train operation. Furthermore, after nitrogen removal, carbon removal, and phosphorus recovery, urine can be disinfected with ultraviolet light and used for toilet flushing, reducing tap water use and thus repurposing urine as a resource. This also reduces initial water carryover and train weight, significantly lowering high-speed train energy consumption. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] One or more embodiments are exemplarily described by the pictures in the corresponding drawings. These exemplifications do not constitute limitations on the embodiments. Unless otherwise stated, the pictures in the drawings do not constitute proportional limitations.

[0025] Figure 1 This is an integrated system for nitrogen and phosphorus removal from urine separated from sources on high-speed trains, provided in Example 1 of the present invention.

[0026] In the figure, 1-source separation toilet, 2-source separation urine storage tank, 3-water inlet pump, 4-liquid flow meter a, 5-water inlet, 6-inner layer, 7-transition zone a, 8-middle layer, 9-transition zone b, 10-outer layer, 11-reflux pump, 12-liquid flow meter b, 13-blower, 14-air flow meter, 15-connection port, 16-water outlet, 17-water production tank, 18-control system, 19-sewage collection tank. DETAILED DESCRIPTION

[0027] The present invention is described in detail below with reference to specific embodiments.

[0028] The present invention provides an integrated system for nitrogen and phosphorus removal from urine separated from high-speed trains. Figure 1 As shown, the system includes: a connected source separation toilet 1 and a coaxial integrated three-stage reactor.

[0029] The source separation toilet 1 is used to separate feces and urine at the source, and transport the separated urine to the coaxial integrated three-stage reactor.

[0030] The coaxial integrated three-stage reactor includes an inner layer 6, a transition zone a7, a middle layer 8, a transition zone b9 and an outer layer 10 which are sequentially connected from the inside to the outside.

[0031] Among them, the inner layer 6 is provided with a water inlet 5, and the water inlet 5 is used to transport the separated urine to the inner layer 6. The inner layer 6 is provided with a sponge filler inoculated with microorganisms; the top of the inner layer 6 is provided with a connection port connected to the transition zone a7.

[0032] The bottom of the transition zone a7 is provided with a connection port connected to the middle layer 8, in which the MABR membrane assembly is provided, and the middle layer 8 is also connected to the blower 13; the top of the middle layer 8 is provided with a connection port 15 connected to the transition zone b9.

[0033] The bottom of the transition zone b9 is provided with a connection port connected to the outer layer 10, and a filter element filled with phosphorus removal adsorbent is provided in the outer layer 10; a water outlet 16 is provided on the outer layer 10, and the water outlet 16 is used to return part of the treated urine to the water inlet 5 and transport the other part to the source separation toilet 1 for flushing.

[0034] It can be understood that a source separation urine storage tank 2 is provided between the source separation toilet 1 and the coaxial integrated three-stage reactor, and the source separation urine storage tank 2 is used to store the separated urine and transport the separated urine to the water inlet 5.

[0035] A water inlet pump 3 and a liquid flow meter a4 are sequentially provided between the source separated urine storage tank 2 and the water inlet 5 .

[0036] A water production tank 17 is further provided between the coaxial integrated three-stage reactor and the source separation toilet 1 . An ultraviolet lamp is provided in the water production tank 17 . The water production tank 17 is used to perform ultraviolet disinfection on the treated urine discharged from the water outlet 16 .

[0037] A reflux pump 11 and a liquid flow meter b12 are sequentially provided between the water outlet 16 and the water inlet 5;

[0038] An air flow meter 14 is further provided between the blower 13 and the middle layer 8 .

[0039] The present invention also provides a method for denitrification and phosphorus removal from source-separated urine on high-speed trains, comprising the following steps: urine enters a source-separated urine storage tank via a source-separated toilet. Fresh urine is source-separated by a water inlet pump and supplied to the inner layer. Microorganisms inoculated in the sponge packing hydrolyze the urea in the urine into ammonia nitrogen, while denitrification removes organic matter and refluxed nitrate nitrogen. The urine then passes through a transition zone a and enters the middle layer, where a MABR membrane module performs integrated partial nitrite / anaerobic ammonium oxidation denitrification. After passing through a transition zone b, the urine enters the outer layer, where a granular FeOOH-biochar composite adsorbent is loaded into a cartridge-type device to form a filtration unit. Phosphate is removed through adsorption, achieving phosphorus removal. After three reuses of the FeOOH-biochar composite, the phosphorus adsorption rate only decreases by 5.1% to 5.7%. The recovered phosphate and the saturated FeOOH-biochar composite that cannot be reused can be used to prepare slow-release phosphate fertilizer, offering economic benefits. A portion of the urine is then recirculated for further denitrification and phosphorus removal. The supernatant after nitrogen and phosphorus removal enters the water production tank for ultraviolet disinfection and is used to flush source-separated toilets. Activated carbon filters are also installed in transition zones a and b to remove odor and pigments, further improving the effluent quality to meet the needs of high-speed train toilet flushing and other applications.

[0040] Example 1: Figure 1 As shown, an integrated system for nitrogen and phosphorus removal from source-separated urine on high-speed trains mainly consists of a source-separated toilet 1, a source-separated urine storage tank 2, a coaxial integrated three-stage reactor, a water production tank 17, a reflux pump 11, a blower 13, a control system 18, and various pipes, valves, water pumps, etc.

[0041] An integrated system for denitrification and phosphorus removal of source-separated urine on high-speed trains. First, urine enters a source-separation toilet 1; the source-separation toilet 1 is then connected to a source-separation urine storage tank 2 and a sewage collection tank 19; the source-separation urine storage tank 2 is connected to an inner layer 6 via a water inlet 5; the inner layer 6 is sequentially connected to a transition zone a7, a middle layer 8, a transition zone b9, and an outer layer 10; a blower 13 is connected to the middle layer 8; a water outlet 16 is connected to the water inlet 5 via a reflux pump 11; and at the same time, a water outlet 21 is connected to a water production tank 22; and the water production tank 22 is then connected to the source-separation toilet 1.

[0042] The post-connection is achieved through different pipes, valves, flow meters and water pumps. The pipes connect the valves, flow meters and water pumps, and the valves, flow meters and water pumps are respectively connected to the source separation toilet 1, the sewage collection tank 19, the source separation urine storage tank 2, the coaxial integrated three-stage reactor, and the water production tank 17 through pipes.

[0043] The present invention addresses the problems that current train toilet collectors only serve as sewage receiving units and do not have any in-situ sewage treatment functions. In addition, the toilet collectors are large in size, the sewage quality and water volume fluctuate greatly, the pollutant concentration is high, and the existing treatment methods are difficult to achieve high-standard emission requirements. The present invention provides an integrated system for source separation of urine for denitrification and phosphorus removal on high-speed trains.

[0044] Example 2: Figure 1 As shown, the present invention provides an integrated system for source separation urine denitrification and phosphorus removal on high-speed trains. The source separation toilet separates feces and urine at the source, and the feces enters the sewage collection box 19 for separate storage and treatment; the source separation urine storage box 2 stores the source separated urine to provide sufficient water for the treatment device; the inner layer 6 is an anaerobic environment, and sponge fillers are loaded in this area to provide an attachment carrier for the survival and reproduction of microorganisms. At the same time, the sponge filler, as a porous substance, is more convenient for sewage to pass through than other substances. The inner layer uses microorganisms to hydrolyze urea to produce ammonia nitrogen, which is then denitrified to remove COD from urine and nitrate nitrogen produced in the middle layer. The middle layer 8 houses a membrane aerated bioreactor (MABR) module, providing an attachment carrier and directional feeding for the microorganisms. In the middle layer 8, ammonia nitrogen produced in the inner layer 6 is converted to nitrite by aerobic ammonia-oxidizing bacteria. Anaerobic ammonia-oxidizing bacteria then convert the nitrite directly into nitrogen gas. A small amount of nitrate nitrogen also flows back into the inner layer 6. The outer layer 10 houses a filter element filled with a granular FeOOH-biochar composite material for phosphorus removal. FeOOH-biochar composite is a highly efficient phosphorus adsorbent synthesized from corn straw and FeCl·6H2O. It offers low cost, resource recovery, and requires no additional materials, making it easy to operate. Activated carbon filters are installed in the reactor's transition zones a7 and b9 to remove odor and urine pigments during the denitrification and phosphorus removal processes. The treated urine is then returned for deep denitrification and phosphorus removal. The effluent after denitrification and phosphorus removal by the coaxial integrated three-stage reactor is stored in a water production tank for ultraviolet disinfection and can be used to flush the source separation toilet 1.

[0045] The present invention provides an integrated system for nitrogen and phosphorus removal from urine separated from high-speed train sources. When applying FeOOH-biochar composite materials, it is only necessary to properly control the pH and regularly replace the adsorbent to achieve the phosphorus removal effect. The operation is simple, no other resources are consumed, and the material cost is estimated to be 40 to 50 yuan per kilogram. It is prepared from recyclable materials such as corn stalks, which is environmentally friendly. At the same time, MABR bubble-free aeration is used, which has high oxygen transfer efficiency, low power consumption, and little impact on volatile substances in the water. The effluent treated by this system can be used to flush toilets, reducing the use of tap water. At the same time, the volume of the entire system is controlled to be smaller than that of the current train sewage collection tank, reducing the energy consumption of the train.

[0046] The integrated system for nitrogen and phosphorus removal from urine separated from high-speed trains, provided by the present invention, features automated control of the reflux pump, water pump, and aeration system. The filtration unit can be replaced as the train unloads waste. The replaced cartridge-type adsorption unit extracts phosphorus through acid leaching, producing a phosphate byproduct for resource utilization.

[0047] Example 3: The present invention also provides a method for separating urine from high-speed trains for nitrogen and phosphorus removal, which is used in the following example: Figure 1 The integrated system for nitrogen and phosphorus removal from urine separated from high-speed train sources includes the following steps:

[0048] Step 1: The urine is separated in the source separation toilet 1 and then enters the source separation urine storage box 2, and then enters the inner layer 6 through the water inlet pump 3 according to the required flow rate;

[0049] In step 2, inner layer 6 creates an anaerobic environment. Urea in the urine is hydrolyzed into ammonia nitrogen by urease-producing microorganisms attached to the sponge filler. The sponge filler does not clog the device and has a certain ability to control urine flow. Simultaneously, denitrifying bacteria in inner layer 6 perform a denitrification reaction, removing nitrate nitrogen that flows back into inner layer 6 and COD in the urine.

[0050] Step 3: The urine treated in the inner layer 6 passes through the transition zone a7, where activated carbon is used to adsorb odor and pigments in the urine. By controlling the flow of urine in and out, the hydraulic retention time (HRT) of the urine in the middle layer 8 is extended, allowing the biochemical reaction in the reactor to proceed more fully.

[0051] In step 4, urine from transition zone a7 enters the middle layer 8, where it undergoes an integrated partial nitritation / anaerobic ammonium oxidation reaction, converting ammonia nitrogen into nitrogen gas and a small amount of nitrate. The MABR membrane modules provide targeted nourishment for nitrite-forming bacteria, reducing power consumption and maintaining low oxygen levels in other areas to facilitate the overall reaction. The treated urine then enters transition zone b9. The process in transition zone b9 is similar to that in transition zone a7, extending the hydraulic retention time of urine in the outer layer 10 and further removing odor and pigments from the urine.

[0052] Step 5: Urine in the transition zone b9 enters the outer layer 10 and passes through the filter element filled with granular FeOOH-biochar composite material. The FeOOH-biochar composite material uses amorphous FeOOH with a large specific surface area (398.66m 2 ·g -1 ) is combined with biochar generated from recyclable materials such as corn stalks. This is resource-friendly and has a high adsorption capacity for phosphates, with optimal adsorption in weakly acidic environments. Phosphorus removal can be achieved simply by controlling the pH. After phosphorus removal in the outer layer 10, the urine is partially recirculated to the inner layer 6 for deep nitrogen and phosphorus removal.

[0053] Step 6: The supernatant after being treated by the coaxial integrated three-stage reactor enters the water production tank 17 and is disinfected by ultraviolet light, and is used to flush the source separation toilet 1.

[0054] In step 1, urine is discharged into the source separation toilet 1 and then enters the source separation urine storage tank 2 after being flushed with about 0.5L of clean water in the water production tank 17. Then, the flow rate of the water inlet pump is controlled according to the HRT of the inner layer 6 and the middle layer 8, and the HRT is 2 to 3h.

[0055] In step 2, the dissolved oxygen (DO) in the upper part is controlled at 0.3-0.5 mg / L by adjusting the air flow of the middle layer MABR, while the DO in the inner layer is 0. The urea in the fresh urine is hydrolyzed by the anaerobic bacteria in the inner layer at a rate of more than 85%.

[0056] After treatment in inner layer 6 in step 4, the remaining urea enters the aerobic MABR zone, where it is further hydrolyzed into ammonia nitrogen by microorganisms. The ammonia nitrogen produced by urea hydrolysis in both zones is treated by the integrated PN / A microorganisms attached to the MABR membrane modules to produce nitrogen gas and some nitrate nitrogen. The ammonia nitrogen removal rate in this zone exceeds 90%, while the nitrate nitrogen produced by the integrated PN / A is approximately 11% of the ammonia nitrogen removal. The inlet pump flow rate is controlled based on the HRT of outer layer 10, which is 6 to 10 hours.

[0057] The adsorption effect of the FeOOH-biochar composite material used in the outer layer 10 in step 5 was 11.39 mg·g -1 , which can meet the needs of urine phosphorus removal.

[0058] The activated carbon added in steps 3 and 5 can be used to absorb and remove volatile nitrogen compounds (such as ammonia and amines) and short-chain fatty acids, along with other odorous substances in urine, reducing odor intensity. It also absorbs natural pigments (such as urobilin) ​​and other colored impurities in urine, improving the liquid's color and making it clearer. The two transition zones extend the hydraulic retention time of urine in the middle layer 8 and outer layer 10, further accurately controlling the efficient progress of each reaction.

[0059] In step 5, the outer layer 10 returns the nitrate nitrogen produced by the integrated PN / A to the inner layer 6 through the reflux pump, and adjusts the liquid flow meter according to the nitrate nitrogen removal situation to control the reflux flow rate. In this area, the denitrifying bacteria use the COD in the urine as an organic carbon source to reduce the nitrate nitrogen to nitrogen gas through denitrification. The nitrate nitrogen removal rate in this area is above 85%, and the COD removal rate is above 90% under the synergistic effect of denitrifying bacteria and other anaerobic heterotrophic bacteria, thereby achieving carbon removal and deep denitrification in the inner layer.

[0060] In step 6, the supernatant after denitrification and decarbonization of the coaxial integrated three-stage reactor enters the water production tank 17 through the water outlet 2 and is used to flush the source separation toilet 1, thereby realizing the resource utilization of urine.

[0061] The coaxial integrated three-stage reactor integrates all reactions, reduces the overall volume, respectively designs the transition area a7 and the transition area b9 to further control the respective reactions, adjusts the hydraulic retention time, improves the treatment efficiency, simultaneously uses the FeOOH-biochar composite material to improve the phosphorus removal effect, realizes resource recycling, meets the purpose of efficient treatment of small space sewage, and can also realize the treatment of other sewage by adjusting the structure and component composition of each layer of the coaxial integrated three-stage reactor, and meets the needs of high-speed train sewage treatment.

[0062] The urine in the high-speed train is treated in situ, the water needed for carrying during train travel is reduced, and the urine accounts for the main component in high-speed train sewage, so that the volume of the sewage collection tank can be reduced by treating the urine. The total volume of the urine denitrification and phosphorus removal system using the high-speed train source separation can be significantly lower than the volume of the current high-speed train sewage collection system.

[0063] Because the wastewater sources of railway stations and sections are dispersed and discontinuous, many stations and sections adopt the centralized collection and treatment mode for the convenience of management, which leads to the mixed treatment of different types of wastewater and causes the fluctuation of treatment effect. The capacity of the clean water tank and the sewage tank in the car is optimized by using an integrated system for urine denitrification and phosphorus removal of high-speed train source separation, and the capacity of a single water tank can be reduced by 160-170L after the modification of 8 marshalling motor trains. After the modification, the total volume of the train can be reduced by about 1 ton, the water consumption is reduced by 43%-47%, the existing high-speed train urine storage and treatment mode is greatly optimized. Secondly, the treatment efficiency verification shows that the urine of about 200L can be treated per day, which can cover the demand of the standard toilet module. In addition, the equipment stability verification shows that the temperature in the car meets the ecological needs of the bacteria, at the same time, the vibration of the high-speed train helps to disperse the sludge particles, improve the nitrogen and phosphorus conversion efficiency, and ensure the long-term stable operation of the system.

[0064] Those skilled in the art can understand that the above-mentioned embodiments are specific embodiments for realizing the present application, and in actual application, various changes can be made in form and details without departing from the spirit and scope of the present application. Any person skilled in the art can make respective changes and modifications without departing from the spirit and scope of the present application, therefore the protection scope of the present application should be limited by the scope defined in the claims.

Claims

1. An integrated system for nitrogen and phosphorus removal from urine separated from high-speed train sources, characterized in that: The system comprises: a connected source separation toilet (1) and a coaxial integrated three-stage reactor; The source separation toilet (1) is used to separate feces and urine at the source, and transport the separated urine to the coaxial integrated three-stage reactor; The coaxial integrated three-stage reactor comprises an inner layer (6), a transition zone a (7), a middle layer (8), a transition zone b (9) and an outer layer (10) which are sequentially connected from the inside to the outside; The inner layer (6) is provided with a water inlet (5), and the water inlet (5) is used to transport the separated urine to the inner layer (6). A sponge filler inoculated with microorganisms is provided in the inner layer (6); and a connection port communicating with the transition zone a (7) is provided at the top of the inner layer (6); The bottom of the transition zone a (7) is provided with a connection port communicating with the middle layer (8), the middle layer (8) is provided with a MABR membrane assembly, and the middle layer (8) is also connected to a blower (13); the top of the middle layer (8) is provided with a connection port (15) communicating with the transition zone b (9); The bottom of the transition zone b (9) is provided with a connection port connected to the outer layer (10), and a filter element filled with a phosphorus removal adsorbent is provided in the outer layer (10); a water outlet (16) is provided on the outer layer (10), and the water outlet (16) is used to return part of the treated urine to the water inlet (5) and transport the other part to the source separation toilet (1) for flushing.

2. The integrated system for nitrogen and phosphorus removal from high-speed train source separated urine according to claim 1 is characterized in that: The phosphorus removal adsorbent is specifically a granular FeOOH-biochar composite material.

3. The integrated system for nitrogen and phosphorus removal from high-speed train source separated urine according to claim 1 is characterized in that: The transition zone a (7) and the transition zone b (9) are both provided with activated carbon, which is used to remove odor and pigments in urine to further improve the water quality of the effluent, thereby meeting other water needs of the high-speed train.

4. The integrated system for nitrogen and phosphorus removal from high-speed train source separated urine according to claim 1, characterized in that: A source separation urine storage tank (2) is provided between the source separation toilet (1) and the coaxial integrated three-stage reactor. The source separation urine storage tank (2) is used to store separated urine and transport the separated urine to the water inlet (5).

5. The integrated system for nitrogen and phosphorus removal from high-speed train source separated urine according to claim 4 is characterized in that: A water inlet pump (3) and a liquid flow meter a (4) are also sequentially arranged between the source-separated urine storage tank (2) and the water inlet (5).

6. The integrated system for nitrogen and phosphorus removal from high-speed train source separated urine according to claim 1, characterized in that: A water production tank (17) is further provided between the coaxial integrated three-stage reactor and the source separation toilet (1), wherein an ultraviolet lamp is provided in the water production tank (17), and the water production tank (17) is used to perform ultraviolet disinfection on the treated urine discharged from the water outlet (16).

7. The integrated system for nitrogen and phosphorus removal from high-speed train source separated urine according to claim 6, characterized in that: A reflux pump (11) and a liquid flow meter b (12) are sequentially provided between the water outlet (16) and the water inlet (5); An air flow meter (14) is also provided between the blower (13) and the middle layer (8).

8. A method for denitrification and dephosphorization of urine separated from high-speed train sources, characterized in that: The method is applied to an integrated system for nitrogen and phosphorus removal from urine separated from a high-speed train source according to any one of claims 1 to 7; the method comprises: First, urine is separated by the source separation toilet (1) and then fed into the inner layer (6) through the water inlet (5). The urea in the urine is hydrolyzed into ammonia nitrogen by microorganisms inoculated in the sponge filler, and denitrification is performed to remove organic matter and refluxed nitric nitrogen. Then it passes through the transition zone a (7) and enters the middle layer (8), where the MABR membrane module is used to perform integrated partial nitrite / anaerobic ammonium oxidation denitrification; After passing through the transition zone b (9), it enters the outer layer (10) and removes phosphates through the adsorption of the phosphorus removal adsorbent to achieve phosphorus removal from urine; Finally, the treated urine is discharged from the water outlet (16), a part of which is refluxed for further denitrification and dephosphorization, and the other part is used to flush the source separation toilet (1).

9. The method for denitrification and dephosphorization of urine separated from high-speed train sources according to claim 8, characterized in that: The air flow rate of the MABR in the middle layer (8) is adjusted to keep the dissolved oxygen (DO) in the upper part at 0.3-0.5 mg / L, while the dissolved oxygen in the inner layer (6) is 0. As a result, the hydrolysis rate of urea in fresh urine by anaerobic bacteria in the inner layer (6) is above 85%.

10. The method for denitrification and dephosphorization of urine separated from high-speed train sources according to claim 8, characterized in that: The hydraulic retention time of the inner layer (6) and the middle layer (8) is 2 to 3 hours; The hydraulic retention time of the outer layer (10) is 2 to 3 hours.

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