Pond culture carbon reduction and sink increase intelligent regulation and control method and system based on water alkalinity regulation and control

Abstract

The invention relates to a pond culture carbon reduction and sink increase intelligent regulation and control method and system based on water alkalinity regulation and control, and the method comprises the steps: 1, configuring an ecological cooperation unit in a culture pond, including putting shellfish seedlings to establish a filter feeding and calcification carbon sink region, and configuring algae to enhance biological carbon sequestration; 2, in the whole cultivation process, an alkalinity regulator is added into the pond through a water alkalinity regulation and control unit, the pH value of the water body is dynamically regulated and controlled and maintained within the target range larger than or equal to 8.2, and therefore the water body is promoted to absorb CO2 in the atmosphere and convert the CO2 into soluble inorganic carbon. According to the method, by precisely regulating and controlling the alkalinity of the water body, constructing an ecological collaborative convergence increasing unit and introducing intelligent monitoring and control, the CO2 absorption capacity of a water-gas interface is maximized, and emission of greenhouse gases such as CH4 in the breeding process is minimized; and healthy growth and stable yield increase of main cultured organisms such as shrimps, crabs, shells and the like are guaranteed while the environmental benefits are realized.

Description

Technical fields:

[0001] This invention belongs to the field of aquaculture technology, specifically relating to an intelligent control method and system for reducing carbon sequestration and increasing carbon sinks in pond aquaculture based on water alkalinity regulation. Background technology:

[0002] Pond aquaculture, especially coastal pond aquaculture, is one of the main modes of global aquatic product supply. However, traditional pond aquaculture systems often involve net emissions of greenhouse gases such as carbon dioxide and methane during the aquaculture process due to feed input, biological metabolism, and decomposition of organic matter, making them potential carbon sources and increasing the carbon footprint of aquaculture.

[0003] In current technologies, research and practice to reduce the environmental impact of aquaculture mainly focus on optimizing feed formulations, reducing energy consumption, and developing multi-trophic level integrated aquaculture. For example, by polyculturing filter-feeding shellfish in ponds, their filter feeding can consume some organic detritus. However, these technologies mostly emphasize emission reduction or utilization, lacking systematic and quantifiable technical solutions for actively enhancing the carbon sequestration function of pond water bodies—that is, enhancing their ability to absorb and fix carbon dioxide from the atmosphere.

[0004] It is well known that the pH value of water is closely related to the form of inorganic carbon and the carbon cycle. Under alkaline conditions, more CO2 in water will be converted into HCO3. - and CO3 2- Alkalinity regulation increases the inorganic carbon content in water bodies, reduces the partial pressure of CO2 in the water, and promotes the absorption of CO2 from the atmosphere at the water-air interface. Simultaneously, the precipitation of calcium carbonate (such as in shellfish shells) can sequester inorganic carbon in solid form for long-term storage. However, excessively high pH values ​​(e.g., >9.0) increase the proportion of non-ionic ammonia in the water, which is toxic to farmed organisms such as crustaceans. Therefore, how to safely and efficiently utilize the principle of alkalinity regulation in aquaculture ponds to achieve a reversal from "carbon source" to "carbon sink" while ensuring the healthy growth of farmed organisms is a pressing technical problem to be solved in this field. Summary of the Invention:

[0005] The technical problem to be solved by this invention is to provide a method and system for intelligent regulation of carbon reduction and carbon sequestration in pond aquaculture based on water alkalinity control. This method and system aim to maximize the CO2 absorption capacity of the water-air interface and minimize the emission of greenhouse gases such as CH4 during the aquaculture process by precisely regulating water alkalinity, constructing ecological synergistic carbon sequestration units, and introducing intelligent monitoring and control. While achieving the above-mentioned environmental benefits, it also ensures the healthy growth and stable production of major aquaculture organisms such as shrimp, crab, and shellfish.

[0006] The technical solution of this invention is to provide an intelligent control method for reducing carbon sequestration and increasing carbon sinks in pond aquaculture based on water alkalinity regulation, comprising the following steps:

[0007] S1: Constructing a foundation for ecological synergy and energy accumulation.

[0008] An ecological synergy unit centered on filter-feeding shellfish (such as hard clams, mud clams, and razor clams) is established in the aquaculture pond. The shellfish farming area occupies approximately one-third of the total pond area. The shellfish filter-feeding process converts uneaten feed and organic detritus, reducing the accumulation of organic matter in the bottom sediment. Simultaneously, the shell calcification process directly fixes inorganic carbon in the water. At the same time, suitable algae are cultivated or introduced to enhance photosynthetic biological carbon fixation. This step is completed in the early stages of aquaculture (e.g., March-April), supplemented by initial alkalinity adjustment (e.g., sprinkling shell powder) to stabilize the water pH at 7.9-8.2, laying the foundation for subsequent intensive control.

[0009] S2: Implement dynamic intelligent regulation of target alkalinity.

[0010] Throughout the entire aquaculture cycle, the pH value of the water body is set and maintained within the target range. Preferably, the target pH range is ≥8.2, more preferably 8.2-8.6, and an instantaneous safe upper limit is set to ≤8.8. When the water pH value is greater than 8.2, studies have shown that the CO2 flux at the water-air interface can change from positive to negative, that is, from emission to absorption.

[0011] Through an intelligent monitoring and control unit, key parameters of the water body are monitored in real time, including at least pH value, total alkalinity, and CO2 flux at the water-air interface. Based on real-time monitoring data and a preset carbon sink optimization model, the intelligent control unit automatically makes decisions and instructs the water alkalinity control unit (such as a variable frequency pump) to add alkaline regulators. The alkaline regulators include, but are not limited to, quicklime, sodium carbonate, sodium bicarbonate, shell powder, or combinations thereof. The addition method adopts a slow-controlled, segmented addition to prevent drastic pH fluctuations. When the pH value is detected to be below the target lower limit (e.g., 8.2), the addition is automatically initiated; when the pH value is detected to be close to the safety upper limit (e.g., >8.7) or the total ammonia concentration is abnormally increased, an early warning is automatically triggered and emergency measures are initiated, such as aeration or water exchange.

[0012] S3: Collaborative management throughout the breeding process.

[0013] Alkalinity control strategies are refined by combining the stocking, growth, and harvesting rhythms of aquaculture species. For example, before and after stocking shrimp and crab larvae, the pH is gradually increased and locked to the optimal range (8.3-8.6) to balance larval survival rate and maximum carbon uptake rate.

[0014] During the mid-stage of aquaculture, reduce the amount of feed given to the main farmed species (swimming crabs and white shrimp) by 12%-18% compared to the usual amount, allowing more uneaten feed to be utilized by the shellfish. Regularly use bottom sediment conditioners such as calcium peroxide to oxidize the bottom environment, which can suppress more than 90% of CH4 emissions.

[0015] In the later stages of aquaculture and during autumn and winter, take advantage of the favorable conditions of lower water temperature, reduced respiration, and enhanced net photosynthesis to appropriately increase the target pH value (e.g., 8.4-8.6) and alkalinity input to carry out a "carbon sequestration sprint".

[0016] After the aquaculture is completed, when harvesting from the dried pond, some bottom mud is retained and quicklime and photosynthetic bacteria are applied to promote the stabilization of residual organic matter and reduce subsequent mineralization emissions.

[0017] S4: Conduct full-cycle carbon sequestration accounting.

[0018] Based on greenhouse gas flux data and aquaculture input-output records collected by intelligent monitoring units, the net carbon emissions and carbon sequestration of the entire aquaculture process are quantitatively assessed, including: CO2 / CH4 flux at the water-air interface and biocarbon sequestration by aquaculture organisms (especially shellfish shells).

[0019] In addition, as a preferred embodiment, the present invention also includes the following step: during the aquaculture process, calcium peroxide bottom conditioner can be applied to the bottom of the pond periodically to suppress CH4 emissions from the bottom sediment.

[0020] The present invention also provides an intelligent control system for implementing the above method, the system comprising:

[0021] Water alkalinity control unit: A device used to store and add alkaline regulators to ponds, such as a lime milk or sodium bicarbonate solution storage tank and delivery pipeline equipped with a variable frequency pump.

[0022] Ecological synergy unit: refers to a specially designated area in a pond for stocking filter-feeding shellfish and / or cultivating macroalgae / microalgae.

[0023] Intelligent monitoring and control unit: includes:

[0024] Sensor array: Deployed in the pond to monitor pH, dissolved oxygen, temperature, total ammonia nitrogen, and CO2 / CH4 flux based on the static box method and other principles in real time.

[0025] Controller: Receives sensor data, has a built-in carbon sink optimization and water quality early warning model, and can automatically calculate and output control commands to the water alkalinity control unit and aeration, water exchange and other execution equipment.

[0026] Human-computer interaction interface: used to display real-time data, set control parameters, view historical records, and receive manual intervention commands.

[0027] Carbon accounting unit: This can be a software module integrated into the controller or a standalone computing platform, used to input various types of data, run carbon accounting models, and output carbon footprint reports.

[0028] Compared with the prior art, the present invention has the following advantages:

[0029] This invention achieves a fundamental reversal of carbon balance characteristics: by precisely controlling the pH of the water body to above 8.2, it transforms aquaculture ponds, traditionally net sources of CO2 emissions, into stable net CO2 sinks. Example data shows that the CO2 flux at the water-air interface increased from +10.32 mg / m³ in conventional ponds. 2 The h-hour emission changed to -30.23 mg / m³ 2 With an absorption rate of h, each acre of pond can absorb an additional 194.7 kg of CO2 equivalent per year.

[0030] It achieved synergistic emission reduction of multiple greenhouse gases: while enhancing CO2 absorption, CH4 emissions were significantly suppressed through measures such as bottom sediment improvement.

[0031] This invention achieves a balance between environmental and economic benefits: while significantly reducing carbon emissions and increasing carbon sequestration, it also improves the aquaculture environment through ecological synergy (shellfish filter feeding and algae oxygen supply).

[0032] It provides an intelligent and operable solution: by integrating real-time monitoring, model decision-making and automatic control, it achieves precise and automated alkalinity regulation, avoiding the lag and uncertainty of manual operation, making the technology suitable for promotion and application in large-scale aquaculture.

[0033] A verifiable carbon sequestration measurement method has been established: the entire method is based on real-time monitoring and a standard accounting model, and the increase in carbon sequestration is measurable, reportable, and verifiable, providing solid technical support for incorporating pond aquaculture into the blue carbon trading or ecological compensation system. Attached image description:

[0034] Figure 1 This is a schematic diagram illustrating the relationship between CO2 flux at the water-air interface of an aquaculture pond and pH in an embodiment of the present invention. Detailed implementation method:

[0035] The present invention will be further described below with reference to specific embodiments:

[0036] A smart control method for carbon reduction and sequestration enhancement in pond aquaculture based on water alkalinity regulation was proposed. This embodiment was implemented in a 15-acre pond along the coast, using a polyculture model of swimming crab, white shrimp, and shellfish. The specific steps are as follows:

[0037] Step 1: Shellfish stocking and initial alkalinity establishment

[0038] Late March to mid-April: Fill the pond to a depth of 30–50 cm and stock with 100–130 kg / mu of shellfish seedlings such as hard clams, razor clams, or clams (based on the total pond area; the actual shellfish farming area is approximately 1 / 3 of the total pond area). 3–7 days after stocking, sprinkle 60–100 kg / mu of calcined shell powder plus photosynthetic bacteria to maintain a pH of 7.9–8.2.

[0039] Step 2: Stocking of white shrimp and increasing alkalinity

[0040] Early May: Stock 1.5 kg / mu of berried white shrimp. 7–10 days before stocking, add 110–160 kg / mu of food-grade quicklime or sodium bicarbonate in 5–6 applications to raise the pH to 8.2–8.5 and stabilize it, allowing the water to begin continuously absorbing CO2 from the atmosphere.

[0041] Step 3: Releasing Three-spotted Swimming Crabs and Locking in Alkalinity

[0042] Late May to early June: Release 1800–2200 swimming crab larvae per acre. Continue to fine-tune the pH for 7 days after release, locking it at 8.3–8.6 to ensure the survival of the crab larvae while maintaining the strongest CO2 absorption rate.

[0043] Step 4, Mid-stage of aquaculture (July–late September): Maintain alkalinity + harvest shrimp in batches + promote shellfish shell formation.

[0044] 24-hour online monitoring plus manual monitoring twice daily for pH and total alkalinity; the intelligent control system automatically controls the variable frequency pump to add 0.5%–2% Ca(OH)2 suspension or NaHCO3 solution when pH < 8.2, based on real-time pH, CO2 flux, and total alkalinity data, at a frequency of 0.3–2 times / day and a single addition amount of 5–15 kg / acre; when pH > 8.7, automatic aeration and water exchange are implemented.

[0045] The amount of feed given to swimming crabs and white shrimp is reduced by 12%–18% compared to conventional ponds, and the remaining feed is converted into soft parts by shellfish filter feeding as much as possible to promote shell growth.

[0046] Apply amino acid fertilizer paste + fermented soybean milk at a rate of 0.5–0.8 kg / mu every 10–15 days to maintain algal dominance and enhance biological carbon sequestration.

[0047] Apply 15–25 kg / acre of calcium peroxide substrate modifier every 25–30 days to inhibit CH4 emissions by more than 90%.

[0048] Starting in early August, large white shrimp are harvested in batches while smaller ones are left to grow, 2-3 times a week, until the end of October. The harvesting period does not affect the growth of shellfish and swimming crabs, and the amount of uneaten food in the water is further reduced after the white shrimp are harvested, resulting in less anaerobic decomposition of organic carbon.

[0049] Step 5, carbon sequestration surge in the later stages of aquaculture (October–December)

[0050] Starting in October, the pH target was raised and stabilized at 8.4–8.6, and the alkalinity input was increased by 25%. Taking full advantage of the favorable conditions of strong photosynthesis and weak respiration in autumn and winter, the CO2 absorption rate continued to increase.

[0051] After the white shrimp were basically caught by the end of October, the amount of feed given to swimming crabs was reduced by another 20%, and the remaining feed was used by shellfish for filter feeding to reduce the accumulation of bottom mud.

[0052] Step 6: Strengthen foreign exchange reserves and concentrate harvesting during the wintering period (January of the following year)

[0053] From December to January, when the water temperature is below 15℃, oxygen consumption during respiration continues to decrease, and CO2 absorption and shellfish calcification in the water are still proceeding slowly. The pH of the water should be kept stable at 8.4-8.6 to enhance the carbon sequestration efficiency of the water.

[0054] In January of the following year, the pond was drained, and three-spined swimming crabs and shellfish were harvested in sequence.

[0055] After draining the pond, retain 12–15 cm of bottom mud and sprinkle 50 kg / mu of quicklime plus photosynthetic bacteria to promote the stabilization of residual organic carbon.

[0056] Calculate the carbon reduction and sequestration at the water-air interface by measuring greenhouse gas fluxes throughout the entire life cycle. See Table 1 for details.

[0057] Table 1

[0058]

[0059] As can be seen, this invention reverses the "net emission" to "net absorption" of CO2 at the water-air interface in aquaculture ponds. The CO2 flux at the water-air interface in conventional ponds is +10.32 mg / m³. 2 •h (represented by net emissions into the atmosphere), the pond of this invention reaches –30.23 mg / m³. 2 •h (represented by net absorption from the atmosphere), resulting in an additional CO2 absorption of approximately 194.7 kg CO2eq per acre per year, fundamentally transforming the greenhouse gas balance of aquaculture water bodies. The CH4 flux at the water-air interface increased from 0.067 mg / m³ in conventional ponds. 2 • h decreased to 0.036 mg / m 2 •h, emission reduction of 46.3%, with an average annual reduction of CH4 emissions of 4.2 kg CO2eq per acre.

[0060] Meanwhile, the annual net exchange of greenhouse gases at the water-air interface improved by 198.9 kg CO2eq / mu. Considering only the directly measurable CO2 and CH4 fluxes at the water-air interface, the net annual emission of conventional ponds is 58.6 kg CO2eq / mu, while the net annual absorption of the ponds of this invention is 140.3 kg CO2eq / mu, a difference of 198.9 kg CO2eq / mu·year, demonstrating a significant effect in emission reduction and carbon sequestration.

[0061] In addition, while achieving significant emission reduction and carbon sequestration, the output of the main farmed species increased instead of decreasing, and the output of co-farmed shellfish increased significantly. Among them, the yield of swimming crab increased from 95 kg / mu to 98 kg / mu, the total output of white shrimp increased from 49 kg / mu to 52 kg / mu, and the output of razor clam increased from 120 kg / mu to 161 kg / mu (an increase of 34.2%), achieving simultaneous low carbon emissions and increased production.

[0062] The above effects can be obtained through on-site measurement using static dark chamber gas chromatography, exhibiting high repeatability and verifiability. All flux data are derived from at least three repeated measurements per month throughout the entire aquaculture cycle, and can be directly used for greenhouse gas emission inventory compilation or blue carbon project registration. Figure 1 As shown, previous research results indicate that pH = 8.2 is the critical value for the CO2 flux at the water-air interface to change from a carbon source to a carbon sink, that is, when pH > 8.2, the water-air interface acts as a sink for atmospheric CO2.

[0063] The intelligent control system of the present invention includes: a sensor group installed in the pond for monitoring pH, dissolved oxygen, ammonia nitrogen, etc.; a data acquisition and controller installed in the management room to receive sensor signals and run control algorithms; an alkaline regulator storage tank and dosing pump to add the agent to the pond according to the controller instructions; an aerator and inlet / outlet valves as emergency control equipment; and a terminal for displaying data and setting parameters.

[0064] The above description only illustrates preferred embodiments of the present invention and should not be construed as limiting the scope of the claims. Any equivalent procedural modifications made using this specification are included within the patent protection scope of this invention.

Claims

1. A smart regulation method for reducing carbon sequestration and increasing carbon sinks in pond aquaculture based on water alkalinity control, characterized in that: include Step 1: Configure ecological synergy units in the aquaculture pond, including introducing shellfish seedlings to establish filter-feeding and calcified carbon sink areas, and introducing algae to enhance biological carbon sequestration; Step 2: Throughout the aquaculture process, alkaline regulators are added to the pond through the water alkalinity control unit to dynamically regulate and maintain the water pH value within the target range of 8.2 or higher, so as to promote the absorption of CO2 from the atmosphere by the water and its conversion into dissolved organic carbon. Step 3: Through intelligent monitoring and control unit, monitor the minimum pH value, total alkalinity and CO2 flux at the water-air interface of the pond water in real time, and automatically control the alkalinity regulation unit to add alkaline regulators based on the monitoring data and the preset control model, so as to maintain the target pH range. Step four: The net carbon emissions and carbon sequestration of the entire pond aquaculture process are calculated using a carbon accounting unit. The calculation includes carbon flux at the water-air interface and carbon from aquaculture organisms.

2. The intelligent control method for carbon reduction and sequestration enhancement in pond aquaculture based on water alkalinity regulation according to claim 1, characterized in that: Step one specifically includes: From late March to mid-April, fill the water and release 100-130 kg / mu of clam, hard clam, or razor clam seedlings. Three to seven days after the initial application, apply 60-100 kg / mu of calcined shell powder and photosynthetic bacteria to establish initial alkalinity and maintain the water pH at 7.9-8.

2.

3. The intelligent control method for carbon reduction and sequestration enhancement in pond aquaculture based on water alkalinity regulation according to claim 1, characterized in that: In step two, the target pH range is 8.2 to 8.6, with an instantaneous upper limit not exceeding 8.

8.

4. The intelligent control method for carbon reduction and sequestration enhancement in pond aquaculture based on water alkalinity regulation according to claim 1, characterized in that: Step one also includes introducing crustacean species for aquaculture; Specifically, this includes releasing white shrimp in early May and swimming crabs from late May to early June.

5. The intelligent control method for carbon reduction and sequestration enhancement in pond aquaculture based on water alkalinity regulation according to claim 1, characterized in that: In step two, the alkaline regulator is one or more of quicklime, sodium carbonate, sodium bicarbonate, and shell powder.

6. The intelligent control method for carbon reduction and sequestration enhancement in pond aquaculture based on water alkalinity control according to claim 1 or 5, characterized in that: In step two, the alkaline regulator is added in a slow, controlled, and segmented manner.

7. The intelligent control method for carbon reduction and sequestration enhancement in pond aquaculture based on water alkalinity regulation according to claim 1, characterized in that: In step three, when the real-time monitored pH value is below 8.2, the intelligent control unit automatically controls the addition of an alkaline regulator. When the real-time monitored pH value is higher than 8.7, aeration and / or water change operations are automatically triggered.

8. The intelligent control method for carbon reduction and carbon sequestration enhancement in pond aquaculture based on water alkalinity control according to claim 1, characterized in that: In step three, the intelligent monitoring and control unit also monitors the total ammonia concentration in the water in real time and triggers water quality control measures when the total ammonia concentration rises to the warning threshold.

9. The intelligent control method for carbon reduction and carbon sequestration enhancement in pond aquaculture based on water alkalinity control according to claim 1, characterized in that: It also includes step five: applying calcium peroxide bottom conditioner to the bottom of the pond regularly during the aquaculture process to inhibit CH4 emissions from the bottom sediment.

10. A smart control system for carbon reduction and sequestration enhancement in pond aquaculture based on water alkalinity regulation, used to implement the method according to any one of claims 1 to 9, characterized in that: include Water alkalinity control unit, used to add alkaline regulators to aquaculture ponds; Ecological synergy units include areas used for the cultivation of shellfish and / or algae; The intelligent monitoring and control unit includes a sensor group for real-time monitoring of water parameters and a controller for automatically controlling the alkalinity regulation unit of the water body based on the monitoring data; The carbon accounting unit is used to calculate the carbon budget of the aquaculture system based on monitoring data and a preset model.

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