A carbon source, ammonia nitrogen and pure water collaborative recovery system and method

Abstract

The present invention provides a system and method for the coordinated recovery of a carbon source, ammonia nitrogen, and pure water. The system of the present invention includes a primary submerged breathable membrane unit, a secondary submerged breathable membrane unit, and a pure water recovery unit; the primary submerged breathable membrane unit includes a raw liquid storage tank, in which a first expansion membrane tube assembly, a first aeration device, and a first temperature controller are provided; the secondary submerged breathable membrane unit includes an acid absorption liquid storage tank, in which a second expansion membrane tube assembly, a second aeration device, and a second temperature controller are provided; the pure water recovery unit includes a pure water storage tank and a third temperature controller; the inlet and outlet of the first expansion membrane tube assembly are connected to the acid absorption liquid storage tank via a liquid inlet pipe and a liquid outlet pipe, and the inlet and outlet of the second expansion membrane tube assembly are connected to the pure water storage tank via a water inlet pipe and a water outlet pipe, and pumps are provided on the liquid inlet pipe and the water inlet pipe. The present invention can achieve coordinated carbon source concentration, ammonia nitrogen recovery, and pure water recovery.

Description

Technical Field

[0001] The present invention relates to the technical field of sewage treatment, and in particular to a system and method for the coordinated recovery of a carbon source, ammonia nitrogen and pure water. Background Art

[0002] Wastewater such as landfill leachate, biogas slurry, and waste biomass anaerobic digestion liquid has the characteristics of high ammonia nitrogen, high organic matter, and high water content. Traditional biological, chemical, and physical treatment methods are difficult to effectively treat. Gas Permeable Membrane (GPM) technology can be applied to the treatment of high ammonia nitrogen wastewater, including the recovery of ammonia nitrogen from landfill leachate, biogas slurry, and waste biomass anaerobic digestion liquid. The gas permeable membrane technology does not require pressurization and can spontaneously separate gaseous ammonia nitrogen NH3 from the feed solution into the acid absorption solution under the drive of the ammonia nitrogen concentration gradient. The NH3 entering the acid absorption solution will combine with the free protons in the acid absorption solution to form non-volatile NH 4+ , and converted into high-value nitrogen fertilizer.

[0003] However, breathable membrane technology typically uses alkaline chemicals to adjust the pH, which can easily lead to NH3 spillage and a low transmembrane rate. This significantly reduces recovery efficiency and increases operating and subsequent processing costs. Furthermore, using alkaline chemicals to adjust the pH can easily lead to concentration polarization, which in turn increases membrane fouling. Furthermore, due to the properties of the breathable membrane, when recovering ammonia nitrogen, water vapor is transferred to the absorption side along with the NH3, increasing the volume of the absorption liquid, reducing the concentration of the recovered ammonia nitrogen product, and increasing subsequent processing costs.

[0004] In view of this, the present invention is proposed. Summary of the Invention

[0005] The purpose of the present invention is to provide a system and method for the coordinated recovery of carbon source, ammonia nitrogen and pure water, which overcomes the problems such as the increase in the volume of the absorption liquid, improves the recovery efficiency of ammonia nitrogen, and synergistically realizes the carbon source concentration, ammonia nitrogen recovery and pure water recovery in the raw liquid.

[0006] The present invention provides a coordinated recovery system for a carbon source, ammonia nitrogen and pure water, comprising a first-level submerged breathable membrane unit, a second-level submerged breathable membrane unit and a pure water recovery unit; wherein the first-level submerged breathable membrane unit comprises a raw liquid storage tank, in which a first expansion membrane tube assembly, a first aeration device and a first temperature controller are provided; the second-level submerged breathable membrane unit comprises an acid absorption liquid storage tank, in which a second expansion membrane tube assembly, a second aeration device and a second temperature controller are provided; the pure water recovery unit comprises a pure water storage tank and a third temperature controller; the inlet and outlet of the first expansion membrane tube assembly are respectively connected to the acid absorption liquid storage tank via a liquid inlet pipe and a liquid outlet pipe, and a liquid inlet pump is provided on the liquid inlet pipe; the inlet and outlet of the second expansion membrane tube assembly are respectively connected to the pure water storage tank via a water inlet pipe and a water outlet pipe, and a water inlet pump is provided on the water inlet pipe.

[0007] Specifically, the first temperature controller is provided with a first temperature sensor and a first heating device for heating the raw liquid in the raw liquid storage tank, and the first temperature controller is used to control the temperature of the raw liquid in the raw liquid storage tank at 55-65°C; the second temperature controller is provided with a second temperature sensor and a second heating device for heating the acid absorption liquid in the acid absorption liquid storage tank, and the second temperature controller is used to control the temperature of the acid absorption liquid in the acid absorption liquid storage tank at 45-55°C; the third temperature controller is provided with a third temperature sensor and a refrigeration device for cooling the pure water absorption liquid in the pure water recovery unit, and the third temperature controller is used to control the temperature of the pure water absorption liquid in the pure water storage tank at 15-25°C.

[0008] The first aeration device and the second aeration device are used to aerate the raw liquid storage tank and the acid absorption liquid storage tank, respectively. Specifically, the first aeration device and the second aeration device include an aerator, a flow meter, a releaser, and a timer switch, respectively. The aerator is connected to the releaser via an aeration pipe. The releaser of the first aeration device is arranged at the bottom of the raw liquid storage tank, and the releaser of the second aeration device is arranged at the bottom of the acid absorption liquid storage tank. The flow meter is arranged on the aeration pipe, and the timer switch is connected to the aerator to control the aeration time. The aeration rate of the first aeration device and the second aeration device is 50-400mL / min / L (i.e., 1L of the liquid to be treated requires 50-400mL of aeration volume per minute), for example, 50-200mL / min / L; the timer switch controls the aeration time interval of the first aeration device and the second aeration device to be 1-6h, for example, 2-6h.

[0009] Furthermore, the first and second expansion membrane tube assemblies each include an expansion membrane tube made of ePTFE, PP, or PVDF. Specifically, the first and second expansion membrane tube assemblies may include multiple expansion membrane tubes, arranged in parallel, with the inlet and outlet ends of the multiple expansion membrane tubes secured via a manifold. The first and second expansion membrane tube assemblies lack housings, with the expansion membrane tubes of the first and second expansion membrane tube assemblies directly exposed to the raw liquid storage tank and the acid absorption liquid storage tank, respectively.

[0010] In the system of the present invention, a circulation pipeline for conveying acid absorption liquid is formed between the expansion membrane tube in the first-level submerged breathable membrane unit and the acid absorption liquid in the acid absorption liquid storage tank, and a circulation pipeline for conveying pure water is formed between the expansion membrane tube in the second-level submerged breathable membrane unit and the pure water absorption liquid in the pure water storage tank; when the system is running, the acid absorption liquid in the acid absorption liquid storage tank circulates between the acid absorption liquid storage tank and the expansion membrane tube of the first expansion membrane tube assembly through the liquid inlet pump, and the ammonia nitrogen and water in the raw liquid in the raw liquid storage tank pass through the expansion membrane tube of the first expansion membrane tube assembly into the acid absorption liquid storage tank, the carbon source in the raw liquid is concentrated, and the ammonia nitrogen is removed; at the same time, the pure water absorption liquid in the pure water storage tank circulates between the pure water storage tank and the expansion membrane tube of the second expansion membrane tube assembly through the water in the acid absorption liquid in the acid absorption liquid storage tank pass through the expansion membrane tube of the second expansion membrane tube assembly into the pure water storage tank, at this time, the water in the acid absorption liquid is recovered to the pure water storage tank, and the ammonium salt in the acid absorption liquid is concentrated and recovered.

[0011] Furthermore, the secondary submerged breathable membrane unit is provided with a pH controller, which can be used to monitor whether there is leakage in the acid absorption liquid and whether concentrated acid needs to be added. It can be understood that the pH controller includes a pH sensor and an acid replenishing device. The pH sensor is used to detect the pH value of the acid absorption liquid. When the pH of the acid in the acid absorption liquid is higher than 2, concentrated acid is added to the acid absorption liquid through the acid replenishing device, so that the pH of the acid in the acid absorption liquid is always maintained below 2.

[0012] The present invention also provides a method for the coordinated recovery of a carbon source, ammonia nitrogen and pure water, which is carried out using the above-mentioned system for the coordinated recovery of a carbon source, ammonia nitrogen and pure water.

[0013] Specifically, the method for synergistically recovering a carbon source, ammonia nitrogen, and pure water of the present invention comprises the following steps:

[0014] S1: Add stock liquid to the stock liquid storage tank, add acid absorption liquid to the acid absorption liquid storage tank, add pure water absorption liquid to the pure water storage tank, start the liquid inlet pump to circulate the acid absorption liquid between the acid absorption liquid storage tank and the first expansion membrane tube assembly, and start the water inlet pump to circulate the pure water absorption liquid between the pure water storage tank and the second expansion membrane tube assembly;

[0015] S2: The raw liquid storage tank and the acid absorption liquid storage tank are aerated respectively by using the first aeration device and the second aeration device, and the temperatures of the raw liquid, the acid absorption liquid and the pure water absorption liquid are controlled respectively, so that the ammonia nitrogen and water in the raw liquid enter the acid absorption liquid storage tank through the first expansion membrane tube assembly, and the water in the acid absorption liquid enters the pure water storage tank through the second expansion membrane tube assembly.

[0016] In the present invention, the stock solution is wastewater containing high concentrations of ammonia nitrogen. It is understood that the stock solution also contains carbon sources such as organic matter. The type of stock solution is not strictly limited and includes, but is not limited to, landfill leachate, biogas slurry, and anaerobic digestion liquid from biomass waste. The acid absorption liquid includes at least one of sulfuric acid solution, hydrochloric acid solution, phosphoric acid solution, and nitric acid solution. The acid concentration in the acid absorption liquid can be 0.05-0.2 mol / L. The pure water absorption liquid can be pure water, recycled water, etc.

[0017] The aeration rates of the first aeration device and the second aeration device are 50-400mL / min / L, for example, 50-200mL / min / L, and the aeration time interval is 1-6h, for example, 2-6h. The first aeration device is used to aerate the stock liquid storage tank. Aeration can increase the pH value of the stock liquid in the stock liquid storage tank, increase the concentration of free NH3 in the stock liquid, and make it easier for free NH3 to enter the first expansion membrane tube assembly and be absorbed by the acid absorption liquid, which can not only avoid NH3 overflow, but also accelerate molecular movement to increase the NH3 transmembrane rate, and the ammonia nitrogen recovery efficiency is higher; at the same time, aeration can also reduce concentration polarization, thereby reducing the contamination of the expansion membrane. The second aeration device is used to aerate the acid absorption liquid storage tank. Aeration can reduce temperature polarization, keep the pure water recovery flux of the second expansion membrane tube unaffected, and NH3 immediately reacts to generate NH after entering the acid absorption liquid from the first expansion membrane tube. 4+ In particular, controlling the aeration rate and aeration time interval mentioned above is beneficial to the efficient recovery of ammonia nitrogen and pure water and reduces the energy consumption of process operation.

[0018] In addition, the temperature of the stock solution is controlled to be 55-65°C, for example, 60-65°C. This temperature is conducive to improving the mass transfer flux of ammonia nitrogen, and at the same time, the mass transfer flux of water vapor is also greatly improved, which is conducive to the conversion of ionized ammonia in the stock solution to free ammonia nitrogen and the permeation of free NH3 and water vapor through the expansion membrane tube of the first expansion membrane tube assembly, thereby improving the carbon source concentration multiple and the pure water recovery efficiency; the temperature of the acid absorption liquid is 45-55°C, for example, 55°C, which forms a temperature difference of 10-20°C with the stock solution, which is conducive to improving the water vapor in the stock solution. The process also improves the mass transfer flux of the gas. Furthermore, an operating temperature of 45-55°C facilitates the passage of water vapor from the acid absorption liquid through the expansion membrane tubes of the second expansion membrane tube assembly and into the pure water recovery unit, reducing the volume of the acid absorption liquid, increasing the ammonia nitrogen concentration in the acid absorption liquid, and simultaneously recovering pure water. The temperature of the pure water absorption liquid is 15-25°C, creating a temperature difference with the temperature of the acid absorption liquid, which increases the transmembrane rate of water vapor and the pure water recovery efficiency. Furthermore, operating at room temperature of 15-25°C reduces process energy consumption. In particular, the temperature of the raw liquid can be controlled to be 10-20°C higher than that of the acid absorption liquid, while the temperature of the acid absorption liquid can be controlled to be 20-40°C higher than that of the pure water absorption liquid. This temperature gradient maximizes the carbon source concentration multiple and the pure water recovery efficiency.

[0019] The carbon source, ammonia nitrogen and pure water coordinated recovery system of the present invention is provided with a primary submerged breathable membrane unit, a secondary submerged breathable membrane unit and a pure water recovery unit. A circulation pipeline for conveying the acid absorption liquid is formed between the acid absorption liquid and the expansion membrane tube of the primary submerged breathable membrane unit, and a circulation pipeline for conveying the pure water is formed between the pure water and the expansion membrane tube of the secondary submerged breathable membrane unit. The temperatures of the raw liquid, the acid absorption liquid and the pure water absorption liquid are controlled respectively by a first temperature controller, a second temperature controller and a third temperature controller. At the same time, the first aeration device and the The second aeration device performs aeration, which greatly increases the pH value and free NH3 concentration of the raw liquid, allowing the free NH3 and water vapor in the raw liquid to pass through the expansion membrane tube of the first expansion membrane tube assembly into the acid absorption liquid storage tank, thereby increasing the carbon source concentration multiple and the pure water recovery efficiency; at the same time, the water vapor in the acid absorption liquid passes through the expansion membrane tube of the second expansion membrane tube assembly into the pure water storage tank, which not only reduces the volume of the acid absorption liquid, but also increases the ammonia nitrogen concentration in the acid absorption liquid, thereby synergistically achieving carbon source concentration, ammonia nitrogen recovery and pure water recovery in the raw liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 It is a structural schematic diagram of the carbon source, ammonia nitrogen and pure water coordinated recovery system of the present invention.

[0022] Description of reference numerals:

[0023] 1: Raw liquid storage tank; 2: First expansion membrane tube assembly; 3: First temperature controller; 4: Acid absorption liquid storage tank; 5: Second expansion membrane tube assembly; 6: Second temperature controller; 7: Pure water storage tank; 8: Third temperature controller; 9: First aerator; 10: First flow meter; 11: First releaser; 12: First timer switch; 13: Second aerator; 14: Second flow meter; 15: Second releaser; 16: Second timer switch; 17: pH controller; 18: Liquid inlet pump; 19: Water inlet pump. DETAILED DESCRIPTION

[0024] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0025] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular also includes the plural. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0026] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0027] Example 1

[0028] like Figure 1As shown, the carbon source, ammonia nitrogen and pure water coordinated recovery system of this embodiment includes a primary submerged breathable membrane unit, a secondary submerged breathable membrane unit and a pure water recovery unit; wherein, the primary submerged breathable membrane unit includes a raw liquid storage tank 1, in which a first expansion membrane tube assembly 2, a first aeration device and a first temperature controller 3 are provided; the secondary submerged breathable membrane unit includes an acid absorption liquid storage tank 4, in which a second expansion membrane tube assembly 5, a second aeration device and a second temperature controller 6 are provided; the pure water recovery unit includes a pure water storage tank 7 and a third temperature controller 8; the inlet and outlet of the first expansion membrane tube assembly 2 are connected to the acid absorption liquid storage tank 4 through a liquid inlet pipe and a liquid outlet pipe, respectively, and a liquid inlet pump 18 is provided on the liquid inlet pipe, and the inlet and outlet of the second expansion membrane tube assembly 5 are connected to the pure water storage tank 7 through a water inlet pipe and a water outlet pipe, respectively, and a water inlet pump 19 is provided on the water inlet pipe.

[0029] The primary submerged breathable membrane unit is primarily used to remove ammonia nitrogen from raw liquid while simultaneously concentrating the carbon source. It features a raw liquid storage tank 1, which is used to store raw liquid. The raw liquid is wastewater containing high concentrations of ammonia nitrogen and organic carbon sources, such as leachate, biogas slurry, or anaerobic digestion liquid from biomass waste. Within this tank 1 lies a first expansion membrane tube assembly 2, comprising multiple expansion membrane tubes made of ePTFE, PP, or PVDF. These tubes are arranged in parallel, with their inlet and outlet ends secured by manifolds. The first expansion membrane tube assembly 2 lacks a housing, and the tubes are directly exposed to the raw liquid storage tank 1. After raw liquid is added to the tank 1, the expansion membrane tubes are immersed in the liquid and in direct contact with it, allowing ammonia nitrogen and water in the liquid to pass through the expansion membrane tubes and enter the acid absorption liquid storage tank 4 of the secondary submerged breathable membrane unit.

[0030] The first-stage submerged breathable membrane unit is equipped with a first aeration device for aerating the raw liquid storage tank 1. Aeration can increase the pH value of the raw liquid and the concentration of free NH3 in the raw liquid, allowing the free NH3 to pass through the expansion membrane tubes of the first expansion membrane tube assembly 2 and be absorbed by the acid absorption liquid in the expansion membrane tubes. This prevents NH3 from overflowing, accelerates the NH3 transmembrane rate, improves the recovery efficiency of ammonia nitrogen, and reduces contamination of the expansion membrane tubes. Specifically, the first aeration device includes a first aerator 9, a first flowmeter 10, a first releaser 11, and a first timer 12. The first aerator 9 is connected to the first releaser 11 via an aeration tube. The first releaser 11 is located at the bottom of the raw liquid storage tank 1 and is used to release bubbles generated by aeration. The first flowmeter 10 is located on the aeration tube. The first timer 12 is connected to the first aerator 9 to control the aeration time. The aeration rate of the first aeration device is 50-400 mL / min / L, and the first timer switch 12 controls the aeration time interval of the first aerator 9 to be 1-6 hours.

[0031] The first-stage submerged breathable membrane unit is equipped with a first temperature controller 3, which is used to control the temperature of the raw liquid in the raw liquid storage tank 1 at 55-65°C. Specifically, the first temperature controller 3 is equipped with a first temperature sensor and a first heating device for heating the raw liquid in the raw liquid storage tank 1. The first heating device heats the raw liquid to a temperature of 55-65°C. Raising the raw liquid temperature to this temperature helps improve the mass transfer flux of ammonia nitrogen in the raw liquid, while also significantly increasing the mass transfer flux of water vapor. This facilitates the permeation of free NH3 and water vapor in the raw liquid through the expansion membrane tubes of the first expansion membrane tube assembly 2, thereby improving the carbon source concentration multiple and the pure water recovery efficiency.

[0032] A circulation pipeline for conveying the acid absorption liquid is formed between the first-stage submerged breathable membrane unit and the acid absorption liquid in the acid absorption liquid storage tank 4. The acid absorption liquid in the acid absorption liquid storage tank 4 circulates between the acid absorption liquid storage tank 4 and the expansion membrane tube of the first expansion membrane tube assembly 2 through the liquid inlet pump 18. By controlling the temperature of the raw liquid and the aeration conditions, the ammonia nitrogen and water in the raw liquid pass through the expansion membrane tube of the first expansion membrane tube assembly 2 and enter the acid absorption liquid storage tank 4, thereby concentrating the carbon source in the raw liquid and removing the ammonia nitrogen.

[0033] The secondary submerged breathable membrane unit is primarily used to concentrate ammonia nitrogen in the acid absorption liquid. It is equipped with an acid absorption liquid storage tank 4, which stores the acid absorption liquid. The acid absorption liquid can be a sulfuric acid solution, hydrochloric acid solution, phosphoric acid solution, nitric acid solution, or the like. The acid concentration in the acid absorption liquid can range from 0.05 to 0.2 mol / L. The second expansion membrane tube assembly 5 includes multiple expansion membrane tubes made of ePTFE, PP, or PVDF. These tubes are arranged in parallel, with their inlet and outlet ends secured by water collectors. The second expansion membrane tube assembly 5 lacks a housing, and its expansion membrane tubes are directly exposed to the acid absorption liquid storage tank 4. After the acid absorption liquid is added to the acid absorption liquid storage tank 4, the expansion membrane tubes of the second expansion membrane tube assembly 5 are immersed in the acid absorption liquid and in direct contact with it, allowing water from the acid absorption liquid to pass through the expansion membrane tubes and enter the pure water storage tank 7.

[0034] The secondary submerged breathable membrane unit is equipped with a second aeration device, which is used to aerate the acid absorption liquid storage tank 4. Aeration can reduce temperature polarization and maintain the pure water recovery flux of the second expansion membrane tube. Specifically, the second aeration device includes a second aerator 13, a second flowmeter 14, a second releaser 15, and a second timer switch 16. The second aerator 13 is connected to the second releaser 15 via an aeration tube. The second releaser 15 is located at the bottom of the acid absorption liquid storage tank 4 and is used to release bubbles generated by aeration. The second flowmeter 14 is installed on the aeration tube, and the second timer switch 16 is connected to the second aerator 13 to control the aeration time. The aeration rate of the second aeration device is 50-400 mL / min / L, and the second timer switch 16 controls the aeration time interval of the second aerator 13 to 1-6 hours.

[0035] The secondary submerged breathable membrane unit is equipped with a second temperature controller 6, which is used to control the temperature of the acid absorption liquid in the acid absorption liquid storage tank 4 at 45-55°C. Specifically, the second temperature controller 6 is equipped with a second temperature sensor and a second heating device for heating the acid absorption liquid in the acid absorption liquid storage tank 4. The second heating device heats the acid absorption liquid to a temperature of 45-55°C. This temperature difference from the original liquid is 10-20°C, which helps improve the mass transfer flux of water vapor in the original liquid. Furthermore, the operating temperature of 45-55°C facilitates the water vapor in the acid absorption liquid to pass through the expansion membrane tubes of the second expansion membrane tube assembly 5 and enter the pure water recovery unit, reducing the volume of the acid absorption liquid, increasing the ammonia nitrogen concentration in the acid absorption liquid, and simultaneously recovering pure water.

[0036] The secondary submerged breathable membrane unit is also provided with a pH controller 17 for monitoring whether there is leakage in the acid absorption liquid and whether concentrated acid needs to be added. Specifically, the pH controller 17 includes a pH sensor and an acid replenishing device. The pH sensor is used to detect the pH value of the acid absorption liquid. When the pH of the acid in the acid absorption liquid is higher than 2, concentrated acid is added to the acid absorption liquid through the acid replenishing device, so that the pH of the acid in the acid absorption liquid is always lower than 2.

[0037] When the system is running, a circulating pipeline for transporting pure water is formed between the expansion membrane tube in the secondary submerged breathable membrane unit and the pure water absorption liquid in the pure water storage tank 7. The pure water absorption liquid in the pure water storage tank 7 circulates between the pure water storage tank 7 and the expansion membrane tube of the second expansion membrane tube assembly 5. The water in the acid absorption liquid passes through the expansion membrane tube of the second expansion membrane tube assembly 5 and enters the pure water storage tank 7. At this time, the water in the acid absorption liquid is recovered to the pure water storage tank 7, and the ammonium salt in the acid absorption liquid is concentrated and recovered.

[0038] The pure water recovery unit is mainly used to recover and store pure water absorption liquid. The pure water recovery unit is provided with a pure water storage tank 7, which is used to store pure water absorption liquid. The pure water absorption liquid can be pure water, recycled water, etc. The pure water recovery unit is provided with a third temperature controller 8, which is used to control the temperature of the pure water absorption liquid in the pure water recovery unit at 15-25°C; specifically, the third temperature controller 8 is provided with a third temperature sensor and a refrigeration device for cooling the pure water absorption liquid in the pure water recovery unit. The refrigeration device is used to maintain the temperature of the pure water absorption liquid at 15-25°C. Maintaining the temperature of the pure water absorption liquid at this temperature is conducive to forming a certain temperature difference with the temperature of the acid absorption liquid, thereby improving the transmembrane rate of water vapor and the recovery efficiency of pure water.

[0039] The carbon source, ammonia nitrogen and pure water collaborative recovery system is used to perform the collaborative recovery of carbon source, ammonia nitrogen and pure water. The steps are as follows:

[0040] S1: Add stock liquid to the stock liquid storage tank 1, add acid absorption liquid to the acid absorption liquid storage tank 4, add pure water absorption liquid to the pure water storage tank 7, start the water inlet pump 19 to circulate the pure water absorption liquid between the pure water storage tank 7 and the second expansion membrane tube assembly 5, and start the liquid inlet pump 18 to circulate the acid absorption liquid between the acid absorption liquid storage tank 4 and the first expansion membrane tube assembly 2;

[0041] S2: Use the first aeration device and the second aeration device to aerate the raw liquid storage tank 1 and the acid absorption liquid storage tank 4 respectively, and at the same time control the temperatures of the raw liquid, acid absorption liquid and pure water absorption liquid respectively, so that the ammonia nitrogen and water in the raw liquid enter the acid absorption liquid storage tank 4 through the first expansion membrane tube assembly 2, and the water in the acid absorption liquid enters the pure water storage tank 7 through the second expansion membrane tube assembly 5.

[0042] Specifically, the aeration rates of the first and second aeration devices are 50-400 mL / min / L, and the aeration interval is 1-6 hours. In addition, the temperature of the stock solution is controlled at 55-65°C, the temperature of the acid absorption liquid is controlled at 45-55°C, and the temperature of the pure water absorption liquid is controlled at 15-25°C.

[0043] The carbon source, ammonia nitrogen and pure water coordinated recovery system of this embodiment is provided with a primary submerged breathable membrane unit, a secondary submerged breathable membrane unit and a pure water recovery unit. A circulation pipeline for conveying the acid absorption liquid is formed between the acid absorption liquid and the expansion membrane tube of the primary submerged breathable membrane unit, and a circulation pipeline for conveying the pure water is formed between the pure water and the expansion membrane tube of the secondary submerged breathable membrane unit. The temperatures of the raw liquid, the acid absorption liquid and the pure water absorption liquid are controlled respectively by the first temperature controller 3, the second temperature controller 6 and the third temperature controller 8. At the same time, the first aeration device and the The second aeration device performs aeration, which greatly increases the pH value and free NH3 concentration of the stock solution, allowing the free NH3 and water vapor in the stock solution to pass through the expansion membrane tube of the first expansion membrane tube assembly 2 and enter the acid absorption liquid storage tank 4, thereby improving the carbon source concentration multiple and the pure water recovery efficiency; at the same time, the water vapor in the acid absorption liquid passes through the expansion membrane tube of the second expansion membrane tube assembly 5 and enters the pure water storage tank 7, which not only reduces the volume of the acid absorption liquid, but also increases the ammonia nitrogen concentration in the acid absorption liquid, thereby synergistically achieving carbon source concentration, ammonia nitrogen recovery and pure water recovery in the stock solution.

[0044] Example 2

[0045] This embodiment provides a method for the coordinated recovery of carbon source, ammonia nitrogen and pure water, which is carried out using the system of Example 1.

[0046] Specifically, the raw liquid of this embodiment is landfill leachate, and the ammonia nitrogen concentration is 4000 mg / L; the system operating parameters are as follows: the material of the expansion membrane tube of the first expansion membrane tube assembly is ePTFE, and the material of the expansion membrane tube of the second expansion membrane tube assembly is ePTFE; the acid absorption liquid uses 1000 mL of 0.05 mol / L sulfuric acid solution, the aeration rate of the first aeration device is 100 mL / min / L, the aeration time interval is 2 hours, and the temperature of the raw liquid is 60°C; the aeration rate of the second aeration device is 100 mL / min / L, the aeration time interval is 2 hours, and the temperature of the acid absorption liquid is 55°C; the temperature of the pure water absorption liquid is 25°C.

[0047] After running for 12 hours, the quality parameters of the stock solution were as follows: the ammonia nitrogen concentration was lower than 5 mg / L, the carbon source in the stock solution was concentrated 2.2 times, the ammonium sulfate was concentrated 1.2 times, and 1100 mL of pure water was recovered.

[0048] Example 3

[0049] This embodiment provides a method for the coordinated recovery of carbon source, ammonia nitrogen and pure water, which is carried out using the system of Example 1.

[0050] Specifically, the raw liquid of this embodiment is biogas slurry, and the ammonia nitrogen concentration is 2000 mg / L; the system operating parameters are as follows: the material of the expansion membrane tube of the first expansion membrane tube assembly is PP, and the material of the expansion membrane tube of the second expansion membrane tube assembly is PP; the acid absorption liquid adopts 0.2 mol / L hydrochloric acid solution, the aeration rate of the first aeration device is 200 mL / min / L, the aeration time interval is 4 hours, and the temperature of the raw liquid is 65°C; the aeration rate of the second aeration device is 200 mL / min / L, the aeration time interval is 4 hours, and the temperature of the acid absorption liquid is 55°C; the temperature of the pure water absorption liquid is 25°C.

[0051] After running for 12 hours, the quality parameters of the stock solution were as follows: the ammonia nitrogen concentration was lower than 5 mg / L, the carbon source in the stock solution was concentrated 4.4 times, and the ammonium sulfate was concentrated 1.2 times.

[0052] Example 4

[0053] This embodiment provides a method for the coordinated recovery of carbon source, ammonia nitrogen and pure water, which is carried out using the system of Example 1.

[0054] Specifically, the raw liquid of this embodiment is anaerobic digestion liquid of biomass waste, and the ammonia nitrogen concentration is 2000 mg / L; the system operating parameters are as follows: the material of the expansion membrane tube of the first expansion membrane tube assembly is PVDF, and the material of the expansion membrane tube of the second expansion membrane tube assembly is PVDF; the acid absorption liquid uses 0.1 mol / L nitric acid solution, the aeration rate of the first aeration device is 50 mL / min / L, the aeration time interval is 6 hours, and the temperature of the raw liquid is 65°C; the aeration rate of the second aeration device is 50 mL / min / L, the aeration time interval is 6 hours, and the temperature of the acid absorption liquid is 55°C; the temperature of the pure water absorption liquid is 15°C.

[0055] After running for 12 hours, the quality parameters of the stock solution were as follows: the ammonia nitrogen concentration was lower than 5 mg / L, the carbon source in the stock solution was concentrated 4.4 times, and the ammonium sulfate was concentrated 1.8 times.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A carbon source, ammonia nitrogen and pure water collaborative recovery system, characterized in that: The invention comprises a first-level submerged breathable membrane unit, a second-level submerged breathable membrane unit and a pure water recovery unit; wherein the first-level submerged breathable membrane unit comprises a raw liquid storage tank, in which a first expansion membrane tube assembly, a first aeration device and a first temperature controller are provided; the second-level submerged breathable membrane unit comprises an acid absorption liquid storage tank, in which a second expansion membrane tube assembly, a second aeration device and a second temperature controller are provided; the pure water recovery unit comprises a pure water storage tank and a third temperature controller; the inlet and outlet of the first expansion membrane tube assembly are connected to the acid absorption liquid storage tank through a liquid inlet pipe and a liquid outlet pipe respectively, and a liquid inlet pump is provided on the liquid inlet pipe, the inlet and outlet of the second expansion membrane tube assembly are connected to the pure water storage tank through a water inlet pipe and a water outlet pipe respectively, and a water inlet pump is provided on the water inlet pipe, and the first temperature controller is used to control the temperature of the raw liquid in the raw liquid storage tank at 60-65 ℃, the raw liquid includes at least one of landfill leachate and biomass waste anaerobic digestion liquid, the second temperature controller is used to control the temperature of the acid absorption liquid in the acid absorption liquid storage tank at 45-55 ℃, and the third temperature controller is used to control the temperature of the pure water absorption liquid in the pure water storage tank at 15-25 ℃, controlling the temperature of the raw liquid to be 10-20 ℃ higher than the temperature of the acid absorption liquid, and at the same time controlling the temperature of the acid absorption liquid to be 20-40 ℃ higher than the temperature of the pure water absorption liquid, the aeration rates of the first aeration device and the second aeration device are both 50-200 mL / min / L, the aeration time interval is 1-6 h, the first expansion membrane tube assembly and the second expansion membrane tube assembly both include expansion membrane tubes, the material of the expansion membrane tubes is ePTFE, PP or PVDF, and the pure water absorption liquid uses pure water or recycled water.

2. The carbon source, ammonia nitrogen and pure water coordinated recovery system according to claim 1, characterized in that: The first temperature controller is provided with a first temperature sensor and a first heating device for heating the raw liquid in the raw liquid storage tank, the second temperature controller is provided with a second temperature sensor and a second heating device for heating the acid absorption liquid in the acid absorption liquid storage tank, and the third temperature controller is provided with a third temperature sensor and a refrigeration device for cooling the pure water absorption liquid in the pure water recovery unit.

3. The carbon source, ammonia nitrogen and pure water coordinated recovery system according to claim 1, characterized in that: The first aeration device and the second aeration device both include an aerator, a flow meter, a releaser and a timer switch. The aerator is connected to the releaser through an aeration pipe. The releaser of the first aeration device is arranged at the bottom of the raw liquid storage tank, and the releaser of the second aeration device is arranged at the bottom of the acid absorption liquid storage tank. The flow meter is arranged on the aeration pipe, and the timer switch is connected to the aerator to control the aeration time.

4. The carbon source, ammonia nitrogen and pure water coordinated recovery system according to claim 1, characterized in that: The secondary submerged breathable membrane unit is equipped with a pH controller.

5. A method for synergistically recovering a carbon source, ammonia nitrogen and pure water, characterized in that: The method is carried out by using the carbon source, ammonia nitrogen and pure water collaborative recovery system described in any one of claims 1 to 4.

6. The method for synergistic recovery of carbon source, ammonia nitrogen and pure water according to claim 5, characterized in that: The steps include: S1: Add stock liquid to the stock liquid storage tank, add acid absorption liquid to the acid absorption liquid storage tank, add pure water absorption liquid to the pure water storage tank, start the liquid inlet pump to circulate the acid absorption liquid between the acid absorption liquid storage tank and the first expansion membrane tube assembly, and start the water inlet pump to circulate the pure water absorption liquid between the pure water storage tank and the second expansion membrane tube assembly; S2: using the first aeration device and the second aeration device to aerate the raw liquid storage tank and the acid absorption liquid storage tank respectively, while controlling the temperatures of the raw liquid, the acid absorption liquid and the pure water absorption liquid respectively, so that the ammonia nitrogen and water in the raw liquid enter the acid absorption liquid storage tank through the first expansion membrane tube assembly, and the water in the acid absorption liquid enters the pure water storage tank through the second expansion membrane tube assembly; The aeration rate of the first aeration device and the second aeration device is 50-200 mL / min / L, and the aeration time interval is 1-6 hours; The raw liquid includes at least one of landfill leachate and biomass waste anaerobic digestion liquid. The temperature of the raw liquid is controlled to be 60-65°C, the temperature of the acid absorption liquid is controlled to be 45-55°C, and the temperature of the pure water absorption liquid is controlled to be 15-25°C. The temperature of the raw liquid is controlled to be 10-20°C higher than the temperature of the acid absorption liquid, and the temperature of the acid absorption liquid is controlled to be 20-40°C higher than the temperature of the pure water absorption liquid. The pure water absorption liquid uses pure water or recycled water.

7. The method for synergistic recovery of carbon source, ammonia nitrogen and pure water according to claim 6, characterized in that: The acid absorbing solution includes at least one of a sulfuric acid solution, a phosphoric acid solution and a nitric acid solution.

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