Ammonia-nitrogen wastewater treatment and carbon dioxide fixation synergistic process system
The closed-loop process system using ZSM-5 molecular sieve and carbon dioxide nanobubble mixture solves the problems of discontinuity and secondary pollution in ammonia nitrogen wastewater treatment, achieving stable purification and resource utilization, and producing high-value ammonium bicarbonate, which is suitable for ammonia nitrogen wastewater treatment in multiple industries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- HANGZHOU SHANGTUO BISHUI ENVIRONMENTAL PROTECTION TECH CO LTD
- Filing Date
- 2026-03-06
- Publication Date
- 2026-05-08
AI Technical Summary
Existing ammonia nitrogen wastewater treatment technologies suffer from problems such as discontinuous treatment, sensitivity to environmental conditions, secondary pollution from traditional acid-base regeneration methods, and low resource utilization. Furthermore, the efficiency of traditional biological methods decreases under low-temperature conditions.
Using ZSM-5 molecular sieve as the adsorption medium and combined with carbon dioxide nanobubble mixture for regeneration, a closed-loop process system is constructed to achieve ammonia nitrogen wastewater purification and ammonium bicarbonate resource utilization. Through the whole-process collaborative control unit, the parameters of each unit are optimized to achieve stable operation and resource utilization.
It achieves stable purification of ammonia nitrogen wastewater and fixation of carbon dioxide, producing high-value ammonium bicarbonate products, reducing operating costs, expanding the scope of application, and meeting low-carbon and environmental protection requirements.
Smart Images
Figure CN121990720A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of ammonia nitrogen wastewater treatment technology, and in particular to a process system for synergistic carbon dioxide fixation in ammonia nitrogen wastewater treatment. Background Technology
[0002] Excessive carbon dioxide emissions have led to global warming, causing a series of serious environmental problems such as glacial melting, sea-level rise, and an increase in extreme weather events. Therefore, fixing captured carbon dioxide or synthesizing it into valuable products is of paramount importance for mitigating the greenhouse effect, promoting the healthy development of the carbon cycle, and achieving sustainable development goals.
[0003] Meanwhile, the treatment of ammonia nitrogen wastewater is a critical issue urgently needing to be addressed in the field of environmental protection. Ammonia nitrogen wastewater originates from a wide range of sources, including industrial production processes such as chemical, pharmaceutical, fertilizer, and coking industries; wastewater from agricultural production involving excessive use of nitrogen and organic fertilizers that flows into water bodies via rainwater runoff; manure and flushing wastewater from livestock and poultry farms; and even domestic sewage. If discharged directly without effective treatment, ammonia nitrogen wastewater will cause severe damage to the ecological environment in many ways. In water bodies, ammonia nitrogen consumes large amounts of dissolved oxygen, causing fish and other aquatic organisms to suffocate and die due to lack of oxygen. It also leads to eutrophication, promoting the excessive proliferation of algae and other plankton, thereby disrupting the ecological balance of aquatic bodies. Regarding soil, ammonia nitrogen wastewater infiltrates the soil, altering its physical and chemical properties, inhibiting the activity of soil microorganisms, reducing soil fertility, and affecting crop growth and yield. From an ecosystem perspective, the discharge of ammonia nitrogen wastewater severely damages the stability of ecosystems and threatens biodiversity. From the perspective of human health, if improperly treated ammonia nitrogen wastewater enters drinking water sources, the ammonia nitrogen may be converted into nitrite. Nitrite combines with proteins in the human body to form nitrosamines, which are potent carcinogens and seriously endanger human health.
[0004] Traditional ammonia nitrogen wastewater treatment primarily relies on biodegradation technology; however, this technology has several limitations. For example, biological nitrification and denitrification processes require long hydraulic retention times, and the denitrification stage often necessitates the addition of an external carbon source to meet reaction demands, which undoubtedly increases carbon dioxide emissions and operational complexity. Furthermore, biological methods are highly sensitive to reaction conditions; even minor changes in environmental factors such as temperature and pH can significantly affect microbial activity. At low temperatures, the rate of enzymatic reactions in microorganisms decreases dramatically, and the activity of nitrifying and denitrifying bacteria is significantly inhibited, potentially even leading to stagnation of life activities, thus greatly reducing the effectiveness of ammonia nitrogen wastewater treatment. Summary of the Invention
[0005] To address the technical problems existing in the prior art, embodiments of the present invention provide a process system for treating ammonia nitrogen wastewater in conjunction with carbon dioxide fixation. The technical solution is as follows:
[0006] On the one hand, a process system for treating ammonia nitrogen wastewater in conjunction with carbon dioxide fixation is provided. The system includes an influent pretreatment unit, an ammonia nitrogen adsorption unit, a carbon dioxide nano-sizing unit, a packing regeneration unit, a product conversion unit, and a full-process collaborative control unit.
[0007] Each unit forms a closed-loop process system through fluid delivery pipelines and control valves. The whole-process collaborative control unit has a built-in multi-parameter coupling algorithm and material balance model to dynamically adjust the operating parameters of each unit. The influent pretreatment unit performs graded purification on medium and high concentration ammonia nitrogen wastewater to remove suspended solids, colloids and calcium and magnesium ions. Its operating intensity is dynamically adjusted according to the adsorption efficiency data of the ammonia nitrogen adsorption unit.
[0008] The ammonia nitrogen adsorption unit is equipped with at least two adsorption tanks connected in parallel. The tanks are filled with ZSM-5 molecular sieve adsorption media. The pore structure and surface adsorption sites of the media are regulated to selectively bind with ammonia nitrogen ions in the wastewater. The two adsorption tanks are operated alternately.
[0009] The carbon dioxide nano-unit uses a combination of ultrasonic cavitation and high-speed shearing to break carbon dioxide gas into nano-sized bubbles and mix them with water to form a regenerated liquid raw material. The amount of carbon dioxide prepared is quantitatively set according to the total amount of ammonia nitrogen adsorbed by the ammonia nitrogen adsorption unit.
[0010] The packing regeneration unit uses carbon dioxide nanobubble mixture as the regeneration medium to replace traditional acid and alkali regenerators. Ion exchange occurs during the contact between the regeneration liquid and the adsorption medium. Ammonia nitrogen ions are removed from the adsorption medium, and carbon dioxide and ammonia nitrogen ions are chemically combined. The flow rate and temperature of the regeneration liquid are set according to the ammonia nitrogen load of the adsorption tank.
[0011] The product conversion unit receives a regenerated liquid containing high concentrations of ammonia nitrogen ions and dissolved carbon dioxide and performs conversion treatment to obtain solid ammonium bicarbonate. The mother liquor and escaping gas during the conversion process are returned to the front-end unit. The whole-process collaborative control unit collects parameters such as ammonia nitrogen concentration, carbon dioxide consumption, regenerated liquid reaction status, and product purity of each unit in real time. Through multi-objective optimization algorithms, the operating parameters of each unit are adjusted to achieve dynamic matching of ammonia nitrogen removal, carbon dioxide binding and product conversion.
[0012] The influent pretreatment unit sequentially performs bar screen filtration, composite coagulation clarification, and ion exchange pretreatment processes. The operating parameters of each process are bidirectionally correlated and adjusted with the operating data of the ammonia nitrogen adsorption unit. The ion exchange pretreatment process uses calcium-magnesium specific exchange resin. The resin undergoes an exchange reaction with calcium and magnesium ions in the wastewater, reducing the competition between calcium and magnesium ions and ammonia nitrogen ions on the adsorption medium surface, and reducing the blockage of the adsorption medium caused by precipitation. The regeneration frequency of the exchange resin is dynamically adjusted according to the operating resistance data of the ammonia nitrogen adsorption unit. The composite coagulation clarification process adds ammonia nitrogen-specific composite coagulant. The coagulant forms flocs with colloidal impurities and some organic pollutants in the wastewater. The amount of coagulant added is adjusted according to the suspended solids content of the influent and the adsorption efficiency data of the ammonia nitrogen adsorption unit. The bar screen filtration process removes large particulate suspended solids and floating matter from the wastewater. The filtration accuracy is set according to the pore size of the subsequent adsorption medium to reduce the blockage of the adsorption medium pores by impurities.
[0013] Beneficial effects
[0014] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:
[0015] 1. By constructing a closed-loop process system integrating influent pretreatment, ammonia nitrogen adsorption, carbon dioxide nanofiberization, packing material regeneration, and product conversion, using ZSM-5 molecular sieve as the adsorption medium and carbon dioxide nanobubble mixture as the regeneration medium, a deep coupling of ammonia nitrogen wastewater purification, carbon dioxide fixation, and ammonium bicarbonate resource utilization is achieved, forming a virtuous cycle of pollution control, carbon fixation, and resource utilization. The alternating operation design of dual adsorption tanks ensures continuous process operation, and the high activity of carbon dioxide nanobubbles enhances ion exchange efficiency. This solves the technical problems of traditional biological methods being sensitive to environmental conditions and having discontinuous treatment, as well as the secondary pollution generated by traditional acid-base regeneration methods, thus improving the stability and environmental friendliness of ammonia nitrogen wastewater treatment.
[0016] 2. By replacing traditional acid-base regenerators with carbon dioxide nanobubble mixtures, carbon dioxide is fixed in a specific direction while molecular sieve regeneration is completed. No additional carbon source is required, avoiding the additional carbon emissions of traditional biological denitrification processes. Furthermore, the gas released during regeneration is recycled after treatment, and the mother liquor from product separation is returned to the system to participate in the reaction again. There are no pollutant emissions throughout the process, which meets the "dual carbon" target requirements and solves the problems of high carbon emissions and serious secondary pollution of traditional technologies, thus enhancing the low-carbon and environmentally friendly attributes of the process.
[0017] 3. The specific adsorption properties of molecular sieves enable efficient capture of ammonia nitrogen. Ammonia nitrogen and carbon dioxide in the regenerated liquid can be directly and directionally converted into ammonium bicarbonate products needed for agriculture, realizing the resource utilization of pollutants. Molecular sieves can be reused after regeneration without frequent replacement, reducing the cost of packing material consumption. At the same time, the products have economic value, bringing additional benefits to enterprises. This solves the problems of low resource utilization and high operating costs of traditional technologies, and improves the economic feasibility of the process.
[0018] 4. By optimizing the characteristics of the adsorption medium and adapting the process parameters, the system can be adapted to ammonia nitrogen wastewater from different industries. At the same time, it can use carbon dioxide captured from industrial tail gas as raw material, without the need for strict restrictions on the source of raw materials. This solves the problems of limited application scenarios and poor raw material adaptability of traditional technologies, and expands the scope of application and prospects for industrial promotion of the process. Attached Figure Description
[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0020] Figure 1 A process flow diagram of an ammonia nitrogen wastewater treatment and carbon dioxide fixation process system provided in this application embodiment. Detailed Implementation
[0021] The technical solution provided in this application will now be described with reference to the accompanying drawings.
[0022] To facilitate understanding of the embodiments of this application, the following points will be explained first:
[0023] First, in this application, "at least one" refers to one or more, and "more than one" refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates an "or" relationship between the preceding and following related objects, but does not exclude the possibility of indicating an "and" relationship. The specific meaning can be understood in the context. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c" can represent: a, b, c; a and b; a and c; b and c; or a and b and c. Here, a, b, and c can be single or multiple.
[0024] Second, in this application, the use of prefixes such as "first" and "second" is merely for the purpose of distinguishing and describing different things belonging to the same name category, and does not constrain the order, size, or quantity of things. For example, "first message" and "second message" are simply different messages, and there is no temporal sequence, size, or priority relationship between them.
[0025] In this embodiment of the invention, sometimes a subscript such as W1 may be written in a non-subscript form such as W1. When the difference is not emphasized, the meaning they express is the same.
[0026] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.
[0027] like Figure 1 As shown in the embodiment of this application, an ammonia nitrogen wastewater treatment and carbon dioxide fixation process system is provided, including an influent pretreatment unit, an ammonia nitrogen adsorption unit, a carbon dioxide nano-sizing unit, a packing regeneration unit, a product conversion unit, and a full-process collaborative control unit.
[0028] Each unit forms a closed-loop process system through fluid delivery pipelines and control valves. The whole-process collaborative control unit has a built-in multi-parameter coupling algorithm and material balance model to dynamically adjust the operating parameters of each unit.
[0029] The influent pretreatment unit performs graded purification of medium- and high-concentration ammonia nitrogen wastewater, removing suspended solids, colloids, and calcium and magnesium ions. Its operating intensity is dynamically adjusted according to the adsorption efficiency data of the ammonia nitrogen adsorption unit.
[0030] The ammonia nitrogen adsorption unit is equipped with at least two adsorption tanks connected in parallel. The tanks are filled with ZSM-5 molecular sieve adsorption media. The pore structure and surface adsorption sites of the media are regulated to selectively bind with ammonia nitrogen ions in the wastewater. The two adsorption tanks are operated alternately.
[0031] The carbon dioxide nano-unit uses a combination of ultrasonic cavitation and high-speed shearing to break carbon dioxide gas into nano-sized bubbles and mix them with water to form a regenerated liquid raw material. The amount of carbon dioxide prepared is quantitatively set according to the total amount of ammonia nitrogen adsorbed by the ammonia nitrogen adsorption unit.
[0032] The packing regeneration unit uses carbon dioxide nanobubble mixture as the regeneration medium to replace traditional acid and alkali regenerators. Ion exchange occurs during the contact between the regeneration liquid and the adsorption medium. Ammonia nitrogen ions are removed from the adsorption medium, and carbon dioxide and ammonia nitrogen ions are chemically combined. The flow rate and temperature of the regeneration liquid are set according to the ammonia nitrogen load of the adsorption tank.
[0033] The product conversion unit receives the regenerated liquid containing high concentrations of ammonia nitrogen ions and dissolved carbon dioxide and performs conversion treatment to obtain ammonium bicarbonate solid. The mother liquor and escaped gas during the conversion process are returned to the front-end unit.
[0034] The whole-process collaborative control unit collects parameters such as ammonia nitrogen concentration, carbon dioxide consumption, regeneration liquid reaction status, and product purity of each unit in real time. Through multi-objective optimization algorithm, the operating parameters of each unit are adjusted to achieve dynamic matching of ammonia nitrogen removal, carbon dioxide binding and product conversion.
[0035] As an optional embodiment, the influent pretreatment unit sequentially performs bar filtration, composite coagulation clarification and ion exchange pretreatment processes, and the operating parameters of each process are bidirectionally correlated and adjusted with the operating data of the ammonia nitrogen adsorption unit;
[0036] The ion exchange pretreatment process uses calcium-magnesium specific exchange resin. The resin undergoes an exchange reaction with calcium and magnesium ions in the wastewater, reducing the competition between calcium and magnesium ions and ammonia nitrogen ions on the adsorption medium surface, reducing the blockage of the adsorption medium caused by precipitation, and dynamically adjusting the regeneration frequency of the exchange resin according to the operating resistance data of the ammonia nitrogen adsorption unit.
[0037] A special composite coagulant for ammonia nitrogen is added in the composite coagulation and clarification process. The coagulant forms flocs with colloidal impurities and some organic pollutants in the wastewater. The dosage of the coagulant is adjusted according to the suspended solids content of the influent and the adsorption efficiency data of the ammonia nitrogen adsorption unit.
[0038] The bar screen filtration process removes large suspended solids and floating matter from wastewater. The filtration precision is set according to the pore size of the subsequent adsorption medium to reduce the clogging of the adsorption medium pores by impurities.
[0039] As an optional embodiment, the pore size of the adsorption medium of the ammonia nitrogen adsorption unit is adjusted to match the diffusion characteristics of ammonia nitrogen ions, and the binding capacity of the surface adsorption sites to ammonia nitrogen ions is enhanced after activation treatment; the filling amount of the adsorption medium and the wastewater retention time are dynamically adjusted according to the effluent ammonia nitrogen concentration and flow rate of the influent pretreatment unit.
[0040] When the ammonia nitrogen concentration in the effluent of one of the adsorption tanks reaches the set value, or when the running time reaches the adsorption saturation judgment time, the whole process collaborative control unit triggers a switching command to stop the water intake of that tank and start the regeneration process, while activating the backup adsorption tank to keep the treatment process running.
[0041] The wastewater flow path in the adsorption tank is reversed from the contact path of the subsequent regenerated liquid, which increases the contact area between the adsorption medium and the wastewater and regenerated liquid.
[0042] As an optional embodiment, the carbon dioxide nanofiber unit sequentially performs carbon dioxide gas purification, nanobubble generation, and constant temperature storage of the mixed liquid, and the operating parameters of each process are related to the packing regeneration unit through the stoichiometric ratio.
[0043] The carbon dioxide gas purification process uses a composite adsorption medium of activated carbon and molecular sieve to remove moisture, sulfides and dust impurities from the carbon dioxide gas captured in industrial tail gas, thereby improving the purity of the carbon dioxide gas and meeting the requirements of the regeneration reaction for the content of gas impurities.
[0044] The nanobubble generation process improves the specific surface area and stability of nanobubbles, enhances the solubility and reactivity of carbon dioxide in water, and matches the generation parameters with the ion exchange reaction parameters of the packing regeneration unit.
[0045] The constant temperature storage process of the mixed solution keeps the regenerated solution within a set temperature range. Continuous stirring reduces the aggregation of nanobubbles, and the storage temperature matches the ion exchange activity parameters of the adsorption medium.
[0046] As an optional embodiment, the contact time between the regeneration liquid and the adsorption medium in the packing regeneration unit is set in the range where ammonia nitrogen ions are completely removed and carbon dioxide is fully combined. The release rate of carbon dioxide nanobubbles is synchronized with the removal rate of ammonia nitrogen ions, reducing the situation where the carbon dioxide concentration in a local area is too high or ammonia nitrogen is not completely removed from the adsorption medium.
[0047] The trace gases generated during the regeneration process are introduced into the gas purification component through the collection pipeline. After the ammonia component is removed by the acid adsorption medium, the unreacted carbon dioxide is returned to the carbon dioxide nano-unit.
[0048] The packing regeneration unit is equipped with a regeneration liquid circulation and purification process. It uses a filter medium to trap molecular sieve debris and tiny impurities carried in the regeneration liquid, reducing the impact of impurity accumulation on the regeneration reaction and pipeline flow.
[0049] As an optional embodiment, part of the regenerated liquid after circulation and purification is returned to the carbon dioxide nano-sizing unit, and the remaining part is transported to the product conversion unit. The return ratio is dynamically adjusted according to the reaction state of the regenerated liquid.
[0050] The carbon dioxide concentration of the reflux regenerated liquid is monitored in real time by the whole process collaborative control unit. Fresh carbon dioxide nanobubble mixture is added according to the concentration change to keep the reactivity of the regenerated liquid within the set range.
[0051] The ratio of the regenerated liquid circulation flow rate to the fresh replenishment amount is set according to the ammonia nitrogen elution requirements and carbon dioxide binding targets of the ammonia nitrogen adsorption unit.
[0052] As an optional embodiment, the product conversion unit sequentially performs pH gradient adjustment, ultrasonic crystallization induction, and solid-liquid separation and purification processes. The operating parameters of each process are adjusted in conjunction with the front-end unit through product purity data. The pH gradient adjustment process adopts a phased addition of a weakly alkaline adjusting solution to gradually adjust the pH of the regenerated solution to the set range for the formation of ammonium bicarbonate. The adjustment rate is matched with the crystal growth rate of the crystallization induction process.
[0053] The ultrasonic crystallization induction process uses a combination of ultrasonic induction and low temperature control technology. The ultrasonic parameters are dynamically adjusted according to the concentration of the regenerated solution to promote uniform growth of ammonium bicarbonate crystals. The temperature range of low temperature control is matched with the crystal purity and growth rate parameters.
[0054] The solid-liquid separation and purification process adopts a combination of high-efficiency filtration and centrifugal separation. The separated solid particles are dried at low temperature to obtain ammonium bicarbonate solid that meets agricultural use standards. The separated mother liquor is returned to the packing regeneration unit.
[0055] As an optional embodiment, the weakly alkaline conditioning solution is a food-grade sodium bicarbonate solution, and the dosage is determined by the whole-process collaborative control unit based on the ammonia nitrogen concentration and carbon dioxide content in the regenerated solution;
[0056] A small amount of carbon dioxide gas that escapes during the crystallization induction process is introduced into the carbon dioxide nano-sizing unit through a recovery pipeline, and the carbon dioxide that does not escape participates in the process cycle again.
[0057] The product conversion unit and the packing regeneration unit form feedback through the quality data of the regenerated liquid. When the ammonia nitrogen concentration in the regenerated liquid is detected to be lower than the set value, the whole process collaborative control unit increases the replenishment of fresh carbon dioxide nanobubble mixture and adjusts the regeneration time of the adsorption tank.
[0058] As an optional embodiment, the multi-parameter coupling algorithm of the whole-process collaborative control unit establishes a quantitative correlation of key parameters of each unit based on the stoichiometric ratio of ammonia nitrogen and carbon dioxide to produce ammonium bicarbonate.
[0059] The correlations include: the relationship between the ion removal rate of the influent pretreatment unit and the adsorption selectivity of the ammonia nitrogen adsorption unit; the relationship between the ammonia nitrogen loading of the ammonia nitrogen adsorption unit and the carbon dioxide supply of the packing regeneration unit; the relationship between the reaction state of the regenerated liquid of the packing regeneration unit and the crystallization efficiency of the product conversion unit; and the relationship between the product purity of the product conversion unit and the recycling ratio.
[0060] The whole-process collaborative control unit receives sensor data from each unit in real time and adjusts the dosage of coagulant in the influent pretreatment, the wastewater retention time for ammonia nitrogen adsorption, the carbon dioxide supply rate for packing regeneration, and the pH adjustment rhythm for product conversion, so that the operating parameters of each unit are dynamically matched.
[0061] As an optional embodiment, the adsorption medium of the ammonia nitrogen adsorption unit is evaluated by periodic sampling and testing. When the adsorption capacity drops to a set value, a regeneration enhancement process or a medium replenishment operation is performed to keep the adsorption performance of the adsorption medium at a set level.
[0062] The whole process collaborative control unit has a preset strategy to deal with abnormal operating conditions. When the water quality of the influent pretreatment unit exceeds the set standard, the ammonia nitrogen adsorption unit extends the wastewater retention time, the packing regeneration unit increases the regeneration liquid concentration, and the product conversion unit suspends the mother liquor return until the pretreated water quality returns to the set range.
[0063] When the carbon dioxide supply in the packing regeneration unit is insufficient, the ammonia nitrogen adsorption unit reduces the influent flow rate, the product conversion unit reduces the pH adjustment rate, and the gas recovery unit increases the recovery of escaping carbon dioxide, so that the carbon dioxide binding amount and product purity are kept within the set range.
[0064] The specific implementation method is as follows:
[0065] Example 1: Treatment of low-concentration ammonia nitrogen wastewater
[0066]
[0067] 1. Influent water quality
[0068] Ammonia nitrogen concentration: 50 mg / L; suspended solids content: 35 mg / L; total calcium and magnesium ion concentration: 50 mg / L; pH value: 7.0-7.5; treatment scale: 0.2 m³ / s. 3 / h.
[0069] 2. Equipment parameters
[0070] Inlet water pretreatment unit: Inlet water pump model ISG25-125 (flow rate 0.2m³ / h) 3 / h, head 20m), pre-filter media porosity 48%, built-in 50μm ceramic filter media;
[0071] Ammonia nitrogen adsorption unit: Adsorption tank volume 0.31m³ 3 The molecular sieve filling amount is 130kg (particle size 2-3mm, pore size 0.52nm, activation temperature 550℃), the filling height is 65% of the tank height, and the wastewater retention time is 2.5h;
[0072] Carbon dioxide nanofiber unit: Nanobubble generator model QSB-0.2 (ultrasonic power 1.5kW, shear speed 3000r / min), mixed liquid CO2 content 1.2g / L, nanobubble diameter 60-80nm;
[0073] Product conversion unit: sodium bicarbonate solution concentration 6%, dosage 0.8L / h, ultrasonic frequency 25kHz, drying temperature 65℃.
[0074] 3. Results
[0075] Effluent water quality: ammonia nitrogen concentration 3.1-4.2 mg / L, suspended solids content ≤2 mg / L;
[0076] CO2 fixation effect: CO2 consumption was 1.18 kg in 24 hours of operation, with a fixation rate of 0.049 kg / t of wastewater;
[0077] Product specifications: Ammonium bicarbonate purity meets agricultural grade requirements, with a moisture content of 4.2%;
[0078] System stability: After 30 days of continuous operation, the adsorption capacity of the packing material after regeneration recovered to a higher level than the initial level, with no pipeline blockage.
[0079] Example 2: Treatment of medium-concentration ammonia nitrogen wastewater (coking cooling wastewater)
[0080] Equipment configuration and parameters
[0081] 1. Influent water quality
[0082] Ammonia nitrogen concentration: 500 mg / L; suspended solids content: 45 mg / L; total calcium and magnesium ion concentration: 80 mg / L; pH value: 7.2-7.8; treatment scale: 0.3 m³ / h. 3 / h.
[0083] 2. Equipment parameters
[0084] Inlet water pretreatment unit: Inlet water pump model ISG40-160 (flow rate 0.3m³ / h) 3 / h, head 25m), pre-filter media porosity 50%, built-in 50μm ceramic filter media;
[0085] Ammonia nitrogen adsorption unit: Adsorption tank volume 1.0 m³ 3 The molecular sieve filling amount is 420 kg (particle size 3-4 mm, pore size 0.55 nm, activation temperature 580 ℃), the filling height is 70% of the tank height, and the wastewater retention time is 3 h;
[0086] Carbon dioxide nanofiber unit: Nanobubble generator model QSB-0.5 (ultrasonic power 2.2kW, shear speed 4000r / min), mixed liquid CO2 content 2g / L, nanobubble diameter 50-70nm;
[0087] Product conversion unit: sodium bicarbonate solution concentration 8%, dosage 2.5L / h, ultrasonic frequency 30kHz, drying temperature 70℃.
[0088] 3. Results
[0089] Effluent water quality: ammonia nitrogen concentration 3.2-4.5 mg / L, suspended solids content ≤1.8 mg / L;
[0090] CO2 fixation effect: 17.28 kg of CO2 was consumed in 24 hours of operation, with a fixation rate of 0.24 kg / t of wastewater;
[0091] Product specifications: Ammonium bicarbonate purity meets agricultural grade requirements, moisture content is 3.8%, and daily output is 19.2 kg;
[0092] System stability: After 30 days of continuous operation, the adsorption capacity of the packing material is restored to a relatively high level after regeneration, and the operating cost is 0.85 yuan / ton of wastewater.
[0093] Example 3: Treatment of high-concentration ammonia nitrogen wastewater (wastewater from a chemical ammonia synthesis workshop)
[0094] Equipment configuration and parameters
[0095]
[0096] 1. Influent water quality
[0097] Ammonia nitrogen concentration: 1000 mg / L; suspended solids content: 55 mg / L; total calcium and magnesium ion concentration: 120 mg / L; pH value: 7.5-8.0; treatment scale: 0.5 m³ / h. 3 / h.
[0098] 2. Equipment parameters
[0099] Inlet water pretreatment unit: Inlet water pump model ISG50-200 (flow rate 0.5m³ / h) 3 / h, head 30m), pre-filter media porosity 52%, built-in 50μm ceramic filter media;
[0100] Ammonia nitrogen adsorption unit: Adsorption tank volume 1.73m³ 3 The molecular sieve filling amount is 730 kg (particle size 4-5 mm, pore size 0.58 nm, activation temperature 600℃), the filling height is 75% of the tank height, and the wastewater retention time is 3.5 h;
[0101] Carbon dioxide nanofiber unit: Nanobubble generator model QSB-1.0 (ultrasonic power 3kW, shear speed 5000r / min), mixed liquid CO2 content 3g / L, nanobubble diameter 50-60nm;
[0102] Product conversion unit: sodium bicarbonate solution concentration 10%, dosage 6.8L / h, ultrasonic frequency 35kHz, drying temperature 75℃.
[0103] 3. Results
[0104] Effluent water quality: ammonia nitrogen concentration 3.5-4.8 mg / L, suspended solids content ≤2.0 mg / L;
[0105] CO2 fixation effect: 57.6 kg of CO2 was consumed in 24 hours of operation, with a fixation rate of 0.48 kg / t of wastewater;
[0106] Product specifications: Ammonium bicarbonate purity meets agricultural grade requirements, moisture content is 3.5%, and daily output is 64.8 kg;
[0107] System stability: After 30 days of continuous operation, the adsorption capacity of the packing material is restored to a relatively high level after regeneration, and the operating cost is 0.92 yuan / ton of wastewater.
[0108] Comparative Example
[0109] Comparative Example 1: Traditional biological nitrification-denitrification process
[0110] Equipment configuration: anaerobic tank + aerobic tank + sedimentation tank (total volume 10m³) 3 Aeration equipment (DO control 2-4 mg / L), methanol dosing system;
[0111] Operating parameters: hydraulic retention time 16h, methanol dosage 2kg / m³ 3 Temperature control: 25-30℃;
[0112] Operating results: Ammonia nitrogen in effluent was 8.5-12 mg / L, with no CO2 fixation effect, operating cost was 2.3 yuan / ton of wastewater, and carbon emissions increased significantly compared to Example 2.
[0113] Comparative Example 2: Traditional Acid-Base Regeneration Molecular Sieve Process
[0114] Equipment configuration: same adsorption tank as in Example 2, regeneration solution is 5% hydrochloric acid solution + 4% sodium hydroxide solution;
[0115] Operating parameters: hydrochloric acid regeneration time 2h, sodium hydroxide neutralization time 1h, regenerated liquid discharge 0.8m³ 3 / d;
[0116] Operating results: Ammonia nitrogen in effluent was 4.2-5.8 mg / L, with no CO2 fixation effect. Additional treatment of acidic and alkaline wastewater was required, resulting in secondary pollution.
[0117] Summary table of key parameters for examples and comparative examples
[0118]
[0119] Based on the summary of key parameters from the examples and comparative examples, the treatment effect and overall performance of the process system of the present invention are significantly better than those of traditional processes: In terms of ammonia nitrogen removal, the effluent ammonia nitrogen concentration of Examples 1-3 is consistently between 3.1 and 4.8 mg / L, which is much lower than that of Comparative Example 1 (8.5-12 mg / L) and Comparative Example 2 (4.2-5.8 mg / L), and it is suitable for ammonia nitrogen wastewater with different concentration ranges of 50-1000 mg / L; In terms of carbon resource utilization, the examples all achieved effective carbon dioxide fixation, with a fixation amount of 0.049-0.48 kg / t wastewater, while neither of the two comparative examples had any carbon dioxide fixation effect, and Comparative Example 1 also had additional carbon emissions;
[0120] In terms of product value and environmental friendliness, the example can stably produce qualified agricultural-grade ammonium bicarbonate without secondary pollution throughout the process. Comparative Example 1 has methanol residue, and Comparative Example 2 produces acid and alkaline wastewater, requiring additional treatment costs. Moreover, the system has strong continuous operation stability and is not affected by environmental conditions such as low temperature.
[0121] The beneficial effects demonstrated in the embodiments are as follows:
[0122] It has high and stable treatment efficiency, significant ammonia nitrogen removal effect, is suitable for wastewater with different concentrations of ammonia nitrogen, is less affected by environmental conditions, and can achieve continuous treatment for 24 hours.
[0123] Low-carbon and environmentally friendly, it requires no external carbon source, simultaneously achieves carbon dioxide fixation, has no secondary pollution emissions, and significantly reduces carbon emissions compared to traditional technologies;
[0124] It has outstanding economic value, and the product is agricultural-grade ammonium bicarbonate, which enables resource recycling and utilization. The molecular sieve can be recycled and regenerated, and the overall operating cost is significantly lower than that of traditional processes.
[0125] With a wide range of applications, it is suitable for the treatment of high-concentration ammonia nitrogen wastewater in multiple industries, and can be adapted to the capture of carbon dioxide from industrial exhaust gas, showing broad prospects for industrial application.
[0126] While an overview of the subject matter has been described with reference to specific example embodiments, various modifications and changes can be made to these embodiments without departing from the broader scope of embodiments of this disclosure. Such embodiments of the subject matter are referred to herein, individually or collectively, as inventions, for convenience only, and if more than one disclosure or concept is disclosed in fact, it is not intended to limit the scope of this application to any single disclosure or concept.
[0127] The embodiments described herein have been described in sufficient detail to enable those skilled in the art to practice the disclosed teachings. Other embodiments may be used and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Therefore, the detailed description should not be construed as limiting, and the scope of the various embodiments is defined only by the appended claims and the full scope of their equivalents.
Claims
1. A process system for treating ammonia nitrogen wastewater in conjunction with carbon dioxide fixation, characterized in that, It includes an influent pretreatment unit, an ammonia nitrogen adsorption unit, a carbon dioxide nano-sizing unit, a packing regeneration unit, a product conversion unit, and a full-process collaborative control unit; Each unit forms a closed-loop process system through fluid delivery pipelines and control valves. The whole-process collaborative control unit has a built-in multi-parameter coupling algorithm and material balance model to dynamically adjust the operating parameters of each unit. The influent pretreatment unit performs graded purification of medium- and high-concentration ammonia nitrogen wastewater, removing suspended solids, colloids, and calcium and magnesium ions. Its operating intensity is dynamically adjusted according to the adsorption efficiency data of the ammonia nitrogen adsorption unit. The ammonia nitrogen adsorption unit is equipped with at least two adsorption tanks connected in parallel. The tanks are filled with ZSM-5 molecular sieve adsorption media. The pore structure and surface adsorption sites of the media are regulated to selectively bind with ammonia nitrogen ions in the wastewater. The two adsorption tanks are operated alternately. The carbon dioxide nano-unit uses a combination of ultrasonic cavitation and high-speed shearing to break carbon dioxide gas into nano-sized bubbles and mix them with water to form a regenerated liquid raw material. The amount of carbon dioxide prepared is quantitatively set according to the total amount of ammonia nitrogen adsorbed by the ammonia nitrogen adsorption unit. The packing regeneration unit uses carbon dioxide nanobubble mixture as the regeneration medium to replace traditional acid and alkali regenerators. Ion exchange occurs during the contact between the regeneration liquid and the adsorption medium. Ammonia nitrogen ions are removed from the adsorption medium, and carbon dioxide and ammonia nitrogen ions are chemically combined. The flow rate and temperature of the regeneration liquid are set according to the ammonia nitrogen load of the adsorption tank. The product conversion unit receives the regenerated liquid containing high concentrations of ammonia nitrogen ions and dissolved carbon dioxide and performs conversion treatment to obtain ammonium bicarbonate solid. The mother liquor and escaped gas during the conversion process are returned to the front-end unit. The whole-process collaborative control unit collects parameters such as ammonia nitrogen concentration, carbon dioxide consumption, regeneration liquid reaction status, and product purity of each unit in real time. Through multi-objective optimization algorithm, the operating parameters of each unit are adjusted to achieve dynamic matching of ammonia nitrogen removal, carbon dioxide binding and product conversion.
2. The ammonia nitrogen wastewater treatment and carbon dioxide fixation process system as described in claim 1, characterized in that, The influent pretreatment unit sequentially performs bar filtration, composite coagulation clarification and ion exchange pretreatment processes, and the operating parameters of each process are bidirectionally correlated and adjusted with the operating data of the ammonia nitrogen adsorption unit. The ion exchange pretreatment process uses calcium-magnesium specific exchange resin. The resin undergoes an exchange reaction with calcium and magnesium ions in the wastewater, reducing the competition between calcium and magnesium ions and ammonia nitrogen ions on the adsorption medium surface, reducing the blockage of the adsorption medium caused by precipitation, and dynamically adjusting the regeneration frequency of the exchange resin according to the operating resistance data of the ammonia nitrogen adsorption unit. A special composite coagulant for ammonia nitrogen is added in the composite coagulation and clarification process. The coagulant forms flocs with colloidal impurities and some organic pollutants in the wastewater. The dosage of the coagulant is adjusted according to the suspended solids content of the influent and the adsorption efficiency data of the ammonia nitrogen adsorption unit. The bar screen filtration process removes large suspended solids and floating matter from wastewater. The filtration precision is set according to the pore size of the subsequent adsorption medium to reduce the clogging of the adsorption medium pores by impurities.
3. The ammonia nitrogen wastewater treatment and carbon dioxide fixation process system as described in claim 1, characterized in that, The pore size of the adsorption medium in the ammonia nitrogen adsorption unit is adjusted to match the diffusion characteristics of ammonia nitrogen ions, and the surface adsorption sites are activated to enhance their binding capacity with ammonia nitrogen ions. The filling amount of the adsorption medium and the wastewater retention time are dynamically adjusted according to the ammonia nitrogen concentration and flow rate of the influent pretreatment unit. When the ammonia nitrogen concentration in the effluent of one of the adsorption tanks reaches the set value, the whole process collaborative control unit triggers a switching command to stop the water intake of that tank and start the regeneration process, while simultaneously activating another adsorption tank to keep the treatment process running. The wastewater flow path in the adsorption tank is reversed from the contact path of the subsequent regenerated liquid, which increases the contact area between the adsorption medium and the wastewater and regenerated liquid.
4. The ammonia nitrogen wastewater treatment and carbon dioxide fixation process system as described in claim 1, characterized in that, The carbon dioxide nanofiber unit sequentially performs carbon dioxide gas purification, nanobubble generation, and constant temperature storage of the mixed liquid. The operating parameters of each process are linked to the packing regeneration unit through the stoichiometric ratio. The carbon dioxide gas purification process uses a composite adsorption medium of activated carbon and molecular sieve to remove moisture, sulfides and dust impurities from the carbon dioxide gas captured in industrial tail gas, thereby improving the purity of the carbon dioxide gas and meeting the requirements of the regeneration reaction for the content of gas impurities. The nanobubble generation process improves the specific surface area and stability of nanobubbles, enhances the solubility and reactivity of carbon dioxide in water, and matches the generation parameters with the ion exchange reaction parameters of the packing regeneration unit. The constant temperature storage process of the mixed solution keeps the regenerated solution within a set temperature range. Continuous stirring reduces the aggregation of nanobubbles, and the storage temperature matches the ion exchange activity parameters of the adsorption medium.
5. The ammonia nitrogen wastewater treatment and carbon dioxide fixation process system as described in claim 4, characterized in that, The contact time between the regeneration liquid and the adsorption medium in the packing regeneration unit is set in the range where ammonia nitrogen ions are completely removed and carbon dioxide is fully combined. The release rate of carbon dioxide nanobubbles is synchronized with the removal rate of ammonia nitrogen ions, reducing the situation where the carbon dioxide concentration in a local area is too high or ammonia nitrogen is not completely removed from the adsorption medium. The trace gases generated during the regeneration process are introduced into the gas purification component through the collection pipeline. After the ammonia component is removed by the acid adsorption medium, the unreacted carbon dioxide is returned to the carbon dioxide nano-unit. The packing regeneration unit is equipped with a regeneration liquid circulation and purification process. It uses a filter medium to trap molecular sieve debris and tiny impurities carried in the regeneration liquid, reducing the impact of impurity accumulation on the regeneration reaction and pipeline flow.
6. The ammonia nitrogen wastewater treatment and carbon dioxide fixation process system as described in claim 5, characterized in that, The recycled liquid after circulation and purification is partially returned to the carbon dioxide nano-sizing unit, and the remaining part is transported to the product conversion unit. The reflux ratio is dynamically adjusted according to the reaction state of the recycled liquid. The carbon dioxide concentration of the reflux regenerated liquid is monitored in real time by the whole process collaborative control unit. Fresh carbon dioxide nanobubble mixture is added according to the concentration change to keep the reactivity of the regenerated liquid within the set range. The ratio of the regenerated liquid circulation flow rate to the fresh replenishment amount is set according to the ammonia nitrogen elution requirements and carbon dioxide binding targets of the ammonia nitrogen adsorption unit.
7. The ammonia nitrogen wastewater treatment and carbon dioxide fixation process system as described in claim 1, characterized in that, The product conversion unit sequentially performs pH gradient adjustment, ultrasonic crystallization induction, and solid-liquid separation and purification processes. The operating parameters of each process are adjusted in conjunction with the front-end unit through product purity data. The pH gradient adjustment process adopts a phased addition of a weakly alkaline adjusting solution to gradually adjust the pH of the regenerated solution to the set range for ammonium bicarbonate generation. The adjustment rate is matched with the crystal growth rate of the crystallization induction process. The ultrasonic crystallization induction process uses a combination of ultrasonic induction and low temperature control technology. The ultrasonic parameters are dynamically adjusted according to the concentration of the regenerated solution to promote uniform growth of ammonium bicarbonate crystals. The temperature range of low temperature control is matched with the crystal purity and growth rate parameters. The solid-liquid separation and purification process adopts a combination of high-efficiency filtration and centrifugal separation. The separated solid particles are dried at low temperature to obtain ammonium bicarbonate solid that meets agricultural use standards. The separated mother liquor is returned to the packing regeneration unit.
8. The ammonia nitrogen wastewater treatment and carbon dioxide fixation process system as described in claim 7, characterized in that, The weakly alkaline conditioning solution is a food-grade sodium bicarbonate solution, and the dosage is determined by the whole-process collaborative control unit based on the ammonia nitrogen concentration and carbon dioxide content in the regenerated solution. A small amount of carbon dioxide gas that escapes during the crystallization induction process is introduced into the carbon dioxide nano-sizing unit through a recovery pipeline, and the carbon dioxide that does not escape participates in the process cycle again. The product conversion unit and the packing regeneration unit form feedback through the quality data of the regenerated liquid. When the ammonia nitrogen concentration in the regenerated liquid is detected to be lower than the set value, the whole process collaborative control unit increases the replenishment of fresh carbon dioxide nanobubble mixture and adjusts the regeneration time of the adsorption tank.
9. The ammonia nitrogen wastewater treatment and carbon dioxide fixation process system as described in claim 1, characterized in that, The multi-parameter coupling algorithm of the whole-process collaborative control unit establishes a quantitative correlation of key parameters of each unit based on the stoichiometric ratio of ammonia nitrogen and carbon dioxide to produce ammonium bicarbonate. The correlations include: the relationship between the ion removal rate of the influent pretreatment unit and the adsorption selectivity of the ammonia nitrogen adsorption unit; the relationship between the ammonia nitrogen loading of the ammonia nitrogen adsorption unit and the carbon dioxide supply of the packing regeneration unit; the relationship between the reaction state of the regenerated liquid of the packing regeneration unit and the crystallization efficiency of the product conversion unit; and the relationship between the product purity of the product conversion unit and the recycling ratio. The whole-process collaborative control unit receives sensor data from each unit in real time and adjusts the dosage of coagulant in the influent pretreatment, the wastewater retention time for ammonia nitrogen adsorption, the carbon dioxide supply rate for packing regeneration, and the pH adjustment rhythm for product conversion, so that the operating parameters of each unit are dynamically matched.
10. The ammonia nitrogen wastewater treatment and carbon dioxide fixation process system as described in claim 3, characterized in that, The adsorption medium of the ammonia nitrogen adsorption unit is sampled and tested periodically to evaluate its adsorption performance. When the adsorption capacity drops to a set value, a regeneration enhancement process or a medium replenishment operation is performed to keep the adsorption performance of the adsorption medium at a set level. The whole process collaborative control unit has a preset strategy to deal with abnormal operating conditions. When the water quality of the influent pretreatment unit exceeds the set standard, the ammonia nitrogen adsorption unit extends the wastewater retention time, the packing regeneration unit increases the regeneration liquid concentration, and the product conversion unit suspends the mother liquor return until the pretreated water quality returns to the set range. When the carbon dioxide supply in the packing regeneration unit is insufficient, the ammonia nitrogen adsorption unit reduces the influent flow rate, the product conversion unit reduces the pH adjustment rate, and the gas recovery unit increases the recovery of escaping carbon dioxide, so that the carbon dioxide binding amount and product purity are kept within the set range.