A multi-stage filtration and purification method and device for sea cucumber ecological farming

Abstract

The present invention relates to the field of sea cucumber aquaculture technology, and discloses a multi-stage filtration and purification method and device for sea cucumber ecological aquaculture, including: establishing two water purification channels, namely a rapid purification channel and a deep purification channel; collecting aquaculture pond water data, determining a stratified control strategy based on the water data, and performing differential extraction of upper and lower water layers; purifying the water body according to the stratified control strategy, and returning the purified water body to the aquaculture pond. The present invention establishes an upper and lower stratified pumping structure and a dual-path purification system, combined with intelligent stratified determination, dual-path flow regulation and synchronous maintenance mechanism, to achieve stratified identification, graded purification and dynamic balance control of multi-source pollution in sea cucumber aquaculture water bodies, thereby improving the bottom pollution removal capacity and upper water body circulation efficiency, ensuring long-term stable operation of the system, effectively improving the water quality environment, and increasing aquaculture survival rate and ecological benefits.

Description

Technical Field

[0001] The invention relates to the technical field of sea cucumber breeding, and in particular to a multi-stage filtration and purification method and device for sea cucumber ecological breeding. Background Art

[0002] As a valuable marine delicacy, sea cucumbers are extremely sensitive to water quality and environmental factors during their ecological aquaculture. High-density, intensive aquaculture, in particular, can lead to accumulation of feed residues and excrement, water stratification, and localized eutrophication. These factors deteriorate the benthic environment and contribute to the accumulation of ammonia, nitrogen, and sulfide, severely impacting growth and survival rates. Single-path purification systems struggle to address the pollution characteristics of different vertical layers of the water, resulting in uneven treatment efficiency and the accumulation of pollution in dead corners.

[0003] Existing aquaculture water treatment systems generally rely on bottom-of-pond pumping and a unified treatment pathway. These systems lack mechanisms for identifying and treating differential pollution in the upper and lower water layers, and fail to fully consider the synergistic needs of operational stability and maintaining bioactivity in the reactor. Under long-term operation or high-load aquaculture conditions, these systems are prone to treatment bottlenecks, high maintenance costs, and significant water quality fluctuations. Summary of the Invention

[0004] In view of the above-mentioned problems, the present invention is proposed.

[0005] Therefore, the technical problem solved by the present invention is that the existing technology has the problems of high maintenance cost and large fluctuation of water quality.

[0006] In order to solve the above technical problems, the present invention provides the following technical solutions: a multi-stage filtration and purification method for ecological aquaculture of sea cucumbers, comprising: establishing two water purification channels, a rapid purification channel and a deep purification channel;

[0007] Collect water data from aquaculture ponds, determine stratification control strategies based on the data, and perform differentiated extraction of upper and lower water layers;

[0008] Water is purified according to the hierarchical control strategy and the purified water is returned to the aquaculture pond.

[0009] As a preferred embodiment of the multi-stage filtration and purification method for ecological aquaculture of sea cucumbers described in the present invention, the rapid purification channel comprises: a first water pumping port extracts upper layer water and sends it into the rapid purification channel;

[0010] The water flows into the mechanical filtration device and the suspended solids are intercepted by the microporous filter and sand filter column;

[0011] The filtered water flows into the UV sterilizer, which uses ultraviolet radiation to inactivate viruses and bacteria in the water;

[0012] The sterilized water flows into the first biological filter tower, where it drips downwards. At the same time, oxygen exchange is active, which promotes the partial transformation of residual organic matter in the water by nitrifying and denitrifying bacteria, reducing oxygen consumption load.

[0013] The purified water falls into the return water reservoir through the waterfall aeration plate, achieving rapid purification of the upper water.

[0014] As a preferred embodiment of the multi-stage filtration and purification method for ecological aquaculture of sea cucumbers according to the present invention, the deep purification channel comprises: a second water pumping port extracts lower layer water and sends it into the deep purification channel;

[0015] The lower layer of water enters the sedimentation device, where the particulate pollutants are settled under low flow conditions;

[0016] The settled water enters the anaerobic reactor equipped with anaerobic granular sludge to biologically reduce the highly oxidized pollutants.

[0017] The water flows into the denitrification device, where external carbon sources are dynamically added according to water quality parameters to strengthen the denitrification reaction and improve the removal efficiency of ammonia nitrogen;

[0018] The water enters the composite adsorption device, which absorbs residual ammonia nitrogen, heavy metal ions and slightly toxic organic matter in the water in layers;

[0019] The water enters the second biological filter, where the ammonia nitrogen and nitrite are biologically oxidized by the metabolism of nitrifying bacteria, and dissolved oxygen in the water is replenished;

[0020] The water enters the dissolved air flotation tank, where microbubble technology is used to separate, float and remove particulate impurities, flocs and residual scum;

[0021] The water enters the aerobic buffer tank to maintain the stability of water alkalinity, hardness and microecology;

[0022] The purified water enters the return water reservoir to achieve deep purification of the lower layer of water.

[0023] As a preferred embodiment of the multi-stage filtration and purification method for sea cucumber ecological farming according to the present invention, the step of determining the hierarchical control strategy based on water body data includes calculating the vertical difference index of the water body data:

[0024] ;

[0025] ;

[0026] ;

[0027] in, Indicates the dissolved oxygen difference; Indicates the upper dissolved oxygen value; Indicates the dissolved oxygen value in the lower layer; Indicates the redox potential difference; represents the upper redox potential; represents the redox potential of the lower layer; Indicates the difference in ammonia nitrogen; Indicates the ammonia nitrogen concentration in the upper layer; Indicates the ammonia nitrogen concentration in the lower layer;

[0028] Based on the aquaculture pond water data, the threshold of the vertical difference index is set, and the judgment logic is expressed as follows:

[0029] ;

[0030] Among them, Count means counting the number of true conditions in the brackets; Indicates the dissolved oxygen difference threshold; Indicates the redox potential difference threshold; Indicates the ammonia nitrogen difference threshold;

[0031] When the judgment logic is met, it means that there is a stratified structure between the upper and lower water bodies. The upper water is purified through the rapid purification channel, and the lower water is purified through the deep purification channel.

[0032] When the judgment logic is not satisfied, it means that there is no stratified structure between the upper and lower water bodies, and the lower water flows into the upper water and is uniformly purified through the rapid purification channel.

[0033] As a preferred embodiment of the multi-stage filtration and purification method for the ecological aquaculture of sea cucumbers described in the present invention, the differential extraction of upper and lower water layers includes encapsulating water body data into a time window sequence and calculating the comprehensive water quality load index for the upper and lower water layers respectively, expressed as:

[0034] ;

[0035] in, represents the water quality load index; i represents the i-th item of data; represents the weight coefficient; x i represents the measured value of the i-th water body data; T i represents the safety limit of the i-th water body data;

[0036] Based on the water quality load index of the upper water body, the long short-term memory neural network is used to generate the upper load forecast value for the next 30 minutes , linearly map the upper load forecast value to obtain the total flow of the next control cycle:

[0037] ;

[0038] in, Indicates the total flow; Indicates the minimum flow rate to maintain circulation; k represents the linear amplification factor;

[0039] Taking the load difference and dissolved oxygen difference between the upper and lower layers, and reasoning based on fuzzy logic rules, the output proportional coefficient controls the pumping multiple of the lower layer:

[0040] ;

[0041] in, represents the proportional coefficient; clip represents the restriction function; f represents the fuzzy inference function; Indicates the load difference between upper and lower layers;

[0042] The double-stage incremental PID is used for flow regulation. First, the upper and lower pumping powers are adjusted to make the total flow meet the requirements. Under the premise of meeting the total flow rate, further fine-tune the upper and lower pumping power to make the flow rate ratio close to the target value. .

[0043] The present invention also provides a multi-stage filtration and purification device for ecological cultivation of sea cucumbers, comprising: a cultivation pond, wherein the cultivation pond is provided with a first water extraction port for extracting upper layer water and a second water extraction port for extracting lower layer water;

[0044] A rapid purification channel, the rapid purification channel sequentially comprising a primary filtration device and a first biological filter tower, the water inlet of the rapid purification channel being connected to the first water pumping port, and the water outlet being returned to the aquaculture pond;

[0045] A deep purification channel, which includes a sedimentation device, an anaerobic reactor, a denitrification device, a composite adsorption device, a second biological filter, a dissolved air flotation tank and an aerobic buffer tank in sequence, wherein the water inlet of the deep purification channel is connected to the second water pumping port, and the water outlet is returned to the aquaculture pond;

[0046] A water quality sensing system, installed at the first water inlet and the second water inlet, for collecting water data of the aquaculture pond;

[0047] A controller is electrically connected to the water quality sensing system, the rapid purification channel and the deep purification channel respectively, determines whether there is pollution stratification in the water body according to the water body data, and controls the operating status and flow ratio of the first water pumping port and the second water pumping port.

[0048] As a preferred embodiment of the multi-stage filtration and purification device for sea cucumber ecological farming according to the present invention, the first water pumping port and the second water pumping port are interconnected through a connecting pipe, three-way valves are provided at both ends of the connecting pipe, and the three-way valves are controlled by a controller;

[0049] The water outlet end of the rapid purification channel is connected to the second water pumping port, which is used to send the return water of the rapid purification channel to the deep purification channel.

[0050] As a preferred embodiment of the multi-stage filtration and purification device for ecological aquaculture of sea cucumbers described in the present invention, the primary filtration device includes a mechanical filtration device and an ultraviolet sterilization device, a waterfall aeration plate is provided at the end of the first biological filter tower, and the height of the first biological filter tower itself is utilized to aerate and oxygenate the return water, and the return water falls into the return water reservoir and is injected into the aquaculture pond through the return pipe.

[0051] The beneficial effects of the present invention are as follows: the present invention establishes an upper and lower layered pumping structure and a dual-path purification system, combined with intelligent layered judgment, dual-path flow regulation and synchronous maintenance mechanism, to achieve layered identification, graded purification and dynamic balance control of multi-source pollution in sea cucumber aquaculture water, thereby improving the bottom pollution removal capacity and upper water body circulation efficiency, ensuring the long-term stable operation of the system, effectively improving the water quality environment, and increasing the aquaculture survival rate and ecological benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only 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.

[0053] Figure 1 A schematic diagram of a multi-stage filtration and purification device for ecological aquaculture of sea cucumbers provided in Example 1 of the present invention;

[0054] Figure 2 This is an overall flow chart of a multi-stage filtration and purification method for ecological aquaculture of sea cucumbers provided in Example 2 of the present invention. DETAILED DESCRIPTION

[0055] To make the above-mentioned objects, features, and advantages of the present invention more clearly understood, the following detailed description of the specific embodiments of the present invention is given in conjunction with the accompanying drawings. It is obvious that the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary persons in this field without creative work should fall within the scope of protection of the present invention.

[0056] Example 1, reference Figure 1 , as one embodiment of the present invention, provides a multi-stage filtration and purification device for ecological aquaculture of sea cucumbers, comprising:

[0057] The aquaculture pond is equipped with a first water inlet for extracting the upper layer of water and a second water inlet for extracting the lower layer of water. The first water inlet is fixed 20-25 cm below the water surface and is constructed as a short side pipe with a protective cover. The second water inlet is fixed at the lowest point of the pond bottom or the center trough, and each is connected to an independent pump and purification line.

[0058] The first water pumping port and the second water pumping port are interconnected through a connecting pipeline. Three-way valves are provided at both ends of the connecting pipeline, and the three-way valves are controlled by a controller.

[0059] The rapid purification channel includes a primary filtration device and a first biological filter tower in sequence. The water inlet of the rapid purification channel is connected to the first water pumping port, and the water outlet flows back to the breeding pond.

[0060] The primary filtration device includes a mechanical filtration device and an ultraviolet sterilization device. A waterfall aeration plate is set at the end of the first biological filter tower, and the height of the first biological filter tower itself is used to aerate and oxygenate the return water. The return water falls into the return water reservoir and is injected into the breeding pond through the return pipe.

[0061] The water outlet end of the rapid purification channel is connected to the second water pumping port, which is used to send the return water of the rapid purification channel to the deep purification channel.

[0062] A deep purification channel includes a sedimentation device, an anaerobic reactor, a denitrification device, a composite adsorption device, a second biological filter, a dissolved air flotation tank and an aerobic buffer tank in sequence. The water inlet end of the deep purification channel is connected to the second water pumping port, and the water outlet end flows back to the breeding pond.

[0063] A water quality sensing system is installed at the first water pumping port and the second water pumping port, and is used to collect water data of the aquaculture pond.

[0064] A controller is electrically connected to the water quality sensing system, the rapid purification channel and the deep purification channel respectively, determines whether there is pollution stratification in the water body according to the water body data, and controls the operating status and flow ratio of the first water pumping port and the second water pumping port.

[0065] Example 2, reference Figure 2 , which is a second embodiment of the present invention, provides a multi-stage filtration and purification method for ecological aquaculture of sea cucumbers, comprising:

[0066] S1: Establish two water purification channels: rapid purification channel and deep purification channel.

[0067] In the sea cucumber ecological aquaculture system constructed by the present invention, the water in the aquaculture pond typically exhibits significant differences in water quality between the upper and lower layers. Especially under medium-to-high density and indoor temperature-controlled conditions, the bottom water is more likely to accumulate harmful substances such as ammonia nitrogen, nitrite, and hydrogen sulfide, while the surface water is relatively clean and has higher dissolved oxygen levels. Therefore, how to identify and quantify this stratified state of water quality is a key prerequisite for determining whether to implement quality-based purification.

[0068] Most existing systems use fixed pumping heights and uniform water treatment processes, and are unable to perceive or respond to changes in the vertical stratification of water bodies. This paper proposes a dynamic stratification determination method that integrates multidimensional water quality parameters to enable intelligent decision-making on pumping strategies and differentiated purification path switching.

[0069] Furthermore, the rapid purification channel is a fast purification path for high-frequency purification treatment to achieve rapid removal of pollutants and efficient water quality maintenance, specifically including the following steps:

[0070] The first water pumping port extracts the upper layer of water and sends it into the rapid purification channel;

[0071] First, the water body is introduced into a mechanical filtration device, which includes a multi-layer microporous filter, a sand filter column or other physical interception device, and is used to efficiently intercept suspended debris, granular algae and uneaten bait in the water;

[0072] The water after mechanical filtration enters the ultraviolet disinfection device, which uses high-intensity ultraviolet radiation to irradiate the water to inactivate pathogenic bacteria, viruses and fungal particles. The ultraviolet disinfection device is set after the mechanical filtration module to avoid interference of suspended particles on the penetration effect of ultraviolet rays.

[0073] The sterilized water is introduced into the first biological filter tower, which includes hydrophilic high specific surface area fillers. Through the dripping form of water, it is fully exposed to the air, promoting the biological transformation reaction of nitrifying bacteria on residual organic matter and soluble nitrogen in the water, and at the same time achieving oxygen recharge;

[0074] The purified water falls into the return water reservoir through the waterfall aeration plate, achieving rapid purification of the upper water.

[0075] It should be noted that waterfall aeration plates are a set of inclined or stepped waterfall aeration plates, positioned between the surface return channel of the aquaculture pond and the surface, creating a high-altitude air-liquid exchange interface before the water falls back into the pond. This waterfall aeration structure utilizes the gravity-induced drop of the trickling filter to effectively increase the dissolved oxygen concentration in the water, enhance the dissipation efficiency of volatile pollutants such as ammonia nitrogen and hydrogen sulfide, and improve the surface microenvironment of the aquaculture pond, providing more optimal ecological conditions for sea cucumbers living on the surface.

[0076] Aerated water flows into a return reservoir located on one side of the system. After sedimentation and conditioning, it is then injected into the upper part of the aquaculture pond through a return pipe. This structure effectively buffers flow rate and water pressure, preventing hydraulic disturbances in the surface living layer of the sea cucumber, thereby improving ecological stability and water quality control accuracy.

[0077] Furthermore, to address the high ammonia nitrogen, high suspended particles, sediment toxins and anaerobic trends often found in the bottom water of sea cucumber aquaculture ponds, the present invention proposes a phased, multi-mechanism coordinated deep purification pathway, which specifically includes the following steps:

[0078] The second pumping port extracts the lower layer water and sends it to the deep purification channel. The lower layer water contains a large amount of residual bait debris, fecal suspended matter and bottom-enriched pollution factors;

[0079] The lower layer of water enters the sedimentation device, and the flow rate is controlled below 0.01m / s, so that large particles of impurities can sink. At the same time, a preliminary anaerobic environment is formed at the bottom of the tank, which is conducive to the initial decomposition of large molecular organic matter.

[0080] The settled water enters the anaerobic reactor equipped with anaerobic granular sludge, where the denitrifying bacteria complete the conversion of nitrate into nitrogen gas, and some sulfate is converted into sulfide for precipitation or escape, thus achieving preliminary denitrification and desulfurization.

[0081] The water flows into the denitrification device. Specifically, an upflow anaerobic reactor (UASB) is combined with a carbon source drip control module to form a denitrification device. The control system automatically adjusts the carbon source drip rate according to real-time nitrite and COD indicators, ensuring reaction efficiency while avoiding carbon source waste, thereby achieving enhanced denitrification and organic load reduction.

[0082] The water enters the composite adsorption device, which consists of a multi-layer structure of zeolite, chitosan and activated carbon, and absorbs residual ammonia nitrogen, heavy metal ions and slightly toxic organic matter in the water in layers;

[0083] The water enters the second biological filter, where the ammonia nitrogen and nitrite are biologically oxidized by the metabolism of nitrifying bacteria, and dissolved oxygen in the water is replenished;

[0084] The water from the biological filter enters the dissolved air flotation tank, where microbubble technology is used to separate, float and remove particulate impurities, flocs and residual scum.

[0085] The water enters the aerobic buffer tank, where the pH is automatically adjusted between 7.5 and 8.2. Water hardness factors such as magnesium and calcium ions are added to maintain a suitable physiological environment and complete partial tail-end denitrification.

[0086] The purified water enters the return water reservoir to achieve deep purification of the lower layer of water.

[0087] It's important to note that in most recirculating aquaculture processes, the deep purification pathway is typically arranged in the order of "aerobic nitrification → anaerobic (or anoxic) denitrification." First, under oxygenated conditions, the most toxic ammonia nitrogen is rapidly oxidized to nitrate. Then, in a deoxygenated environment, organic carbon acts as an electron donor, reducing the nitrate to nitrogen gas, completing both detoxification and denitrification. Furthermore, high aeration in the aerobic stage helps maintain biofilm stability, and placing the denitrification stage at the end, where the load has been reduced, makes it easier to control safety risks.

[0088] However, sea cucumbers are nocturnal and move very slowly. The bottom water lacks active stirring, and the density of their food (seaweed powder, crushed seaweed, etc.) and feces is close to that of suspended solids in the water. The bottom water of sea cucumber ecological breeding ponds has water quality characteristics that are significantly different from those of general circulating water systems. The bottom water is in a state of high COD, high NH3-N, low DO, and enriched in sulfate and sedimentary organic debris for a long time.

[0089] If the order of aerobic first and then anaerobic is still used, high-intensity aeration must be used when the COD is very high. Not only will it consume a lot of energy, but the high COD will also inhibit the activity of nitrifying bacteria, leading to the retention of nitrite and nitrate. At the same time, after sulfate enters the aerobic section, it is easy to dissolve and accumulate with hydrogen sulfide, causing chronic toxicity to benthic sea cucumbers.

[0090] Based on the above-mentioned contradiction between water quality and energy consumption, the present invention arranges the process sections in reverse, adopting the sequence of "anaerobic-denitrification-desulfurization→aerobic nitrification": first, anaerobic granular sludge is used to complete denitrification and sulfate reduction in a natural low-oxygen, high-carbon environment, directly consuming excess organic matter and significantly reducing the risks of COD and hydrogen sulfide (corresponding to the anaerobic reactor and denitrification device); then, under the condition that COD has been significantly reduced, it enters the aerated biological filter for nitrification (the second biological filter), avoiding nitrification inhibition and reducing the aeration volume by about 20%.

[0091] The deep purification pathway can achieve stable purification of the lower layer of highly polluted water bodies through the anaerobic-facultative-aerobic biological section plus adsorption-clarification-physical reflux coupling structure, and build a micro-ecosystem with stable dissolved oxygen, controllable toxins, and slow and steady water flow for the benthic living layer of sea cucumbers.

[0092] S2: Collect water data from the aquaculture pond, determine the stratification control strategy based on the water data, and perform differentiated extraction of upper and lower water layers.

[0093] Furthermore, dissolved oxygen (DO) probes, oxidation-reduction potential (ORP) probes, and ammonia nitrogen (NH3-N) sensors are deployed in the upper layer (about 20 cm from the water surface) and lower layer (about 5 cm from the bottom of the pond) of the aquaculture pond respectively. The controller collects data from the upper and lower layer probes at a regular period (e.g., every 5 minutes) to obtain water body data of the two layers of water.

[0094] The key point of the tiered control strategy is whether the surface pollution is light and can be circulated through a fast path; while the bottom pollution is concentrated and requires special treatment. Therefore, the vertical difference index is used as the basis for judging whether to implement tiered control. Calculate the vertical difference index of water body data:

[0095] ;

[0096] ;

[0097] ;

[0098] in, Indicates the dissolved oxygen difference; Indicates the upper dissolved oxygen value; Indicates the dissolved oxygen value in the lower layer; Indicates the redox potential difference; represents the upper redox potential; represents the redox potential of the lower layer; Indicates the difference in ammonia nitrogen; Indicates the ammonia nitrogen concentration in the upper layer; Indicates the ammonia nitrogen concentration in the lower layer.

[0099] Based on the aquaculture pond water data, the threshold of the vertical difference index is set, and the judgment logic is expressed as follows:

[0100] ;

[0101] Among them, Count means counting the number of true conditions in the brackets; Indicates the dissolved oxygen difference threshold; Indicates the redox potential difference threshold; Indicates the ammonia nitrogen difference threshold.

[0102] When the judgment logic is met, it means that there is a layered structure between the upper and lower water bodies. The upper water is purified through the rapid purification channel, and the lower water is purified through the deep purification channel.

[0103] If the judgment logic is not met, indicating that the upper and lower water layers do not have a stratified structure, the lower water layer is connected to the upper water layer through the connecting pipe and purified uniformly through the rapid purification channel. To prevent large amounts of solid sediment from entering the upper purification path when pumping water from the bottom layer, causing blockage or reducing purification efficiency, the system limits the operating frequency of the lower layer pump, ensuring that its pumping rate does not exceed 30–40% of the upper layer pump. Furthermore, a flow-limiting baffle or slow-start valve group is installed in the bottom pump pipe to ensure that the pumping process does not cause significant mud disturbance, maintaining the stability of the sediment structure at the bottom of the aquaculture pond.

[0104] Compared to existing water purification methods that rely on fixed-height pumping and single-path processing, this invention utilizes a differential-driven stratified recognition mechanism, which not only accurately adapts to different aquaculture stages and pollution conditions but also prevents water quality fluctuations caused by disturbance of contaminated sediment by controlling the pumping rate of the lower layer. Furthermore, when pollution stratification is not significant, the system defaults to a dual-inlet, unified-path treatment approach, ensuring rapid water renewal while avoiding unnecessary waste of processing resources, demonstrating excellent adaptability and operational stability.

[0105] It should be noted that under normal circumstances, the water quality dynamics of the bottom and upper layers of sea cucumbers are usually significantly different. However, under special conditions such as equipment damage, the water pollution in both the upper and lower layers may be serious. Therefore, the vertical difference index is only used to determine whether to start the stratified control strategy. Whether the lower layer water needs to be deeply purified can be determined by comparing the real-time water data with the fixed pollution threshold.

[0106] Furthermore, multi-stage circulation purification systems often employ fixed pumping ratios and power levels, maintaining a constant daily total flow rate and fine-tuning the pumping ratio between the upper and lower layers based on experience. This control model struggles to adapt to the complex and changing characteristics of water pollution, particularly when both upper and lower layers are contaminated but stratification is not evident, or when pollution trends rapidly worsen in the future. This can lead to delayed purification responses and prolonged excessive loading on the lower layer.

[0107] To this end, this paper proposes a dual-path flow self-balancing method based on a multi-index comprehensive water quality load index, combined with time series prediction and fuzzy logic reasoning. Through two-level closed-loop control, the total pumping power and the upper and lower layer pumping ratio are dynamically adjusted simultaneously, so that the purification response accurately matches the water body load, achieving more energy-saving and stable ecological maintenance effects. Specifically, the water body data is encapsulated as a time window sequence, and the comprehensive water quality load index is calculated for the upper and lower water bodies respectively, expressed as:

[0108] ;

[0109] in, represents the water quality load index; i represents the i-th item of data; represents the weight coefficient; x i represents the measured value of the i-th water body data; T i Represents the safety limit of the i-th water body data.

[0110] Based on the water quality load index of the upper water body, the long short-term memory neural network is used to generate the upper load forecast value for the next 30 minutes , in order to predict the changing trend of water body load in advance. The prediction results guide the dynamic adjustment of total pumping power, giving the system forward-looking response capabilities.

[0111] The upper water layer is the area that most quickly reflects changes in purification capacity and system load. Given the specific pump type and piping configuration of the present invention, the pollution reduction rate of the circulating water system is approximately linearly positively correlated with the total flow rate. Therefore, the total flow rate for the next control cycle is obtained by linear mapping the upper load prediction value:

[0112] ;

[0113] in, Indicates the total flow; represents the minimum flow rate required to maintain circulation; k represents the linear amplification factor. When the load increases in the future, the system automatically increases the total pumping power to speed up water turnover. The total flow rate is also clipped within the maximum pumping capacity to prevent overload.

[0114] It should be noted that the total flow of the next control cycle here is the total flow from the predicted time point to the predicted time point, that is, from the moment of prediction to 30 minutes later is a control cycle, and the total pumping volume during this period is .

[0115] Taking the load difference and dissolved oxygen difference between the upper and lower layers, the controller outputs a proportional coefficient to control the lower layer pumping multiple according to the preset expert rule table and fuzzy logic rule reasoning:

[0116] ;

[0117] in, represents the proportional coefficient; clip represents the restriction function; f represents the fuzzy inference function; Indicates the load difference between the upper and lower layers.

[0118] The double-stage incremental PID is used for flow regulation. First, the upper and lower pumping powers are adjusted to make the total flow meet the requirements. Under the premise of meeting the total flow rate, further fine-tune the upper and lower pumping power to make the flow rate ratio close to the target value. .

[0119] On the basis of the dual circulation path of "upper layer rapid purification-lower layer deep purification" constructed by the present invention, a dual-path flow self-balancing method is adopted. The upper layer load prediction only adjusts the total circulation rate through the linear mapping formula, and releases the pump power in advance to cope with the trend of overall water quality deterioration. The real-time difference only adjusts the deep and shallow water extraction ratio through the fuzzy inference function, so that the new flow is preferentially flowed to the bottom pollution-enriched area; and then the two-stage incremental PID is used to first lock the total flow and then fine-tune the ratio to ensure that the two groups of variable frequency pumps do not oscillate with each other.

[0120] Under the same stocking density and feeding conditions, this method combination not only shortens the peak suppression time of bottom ammonia nitrogen at night, but also reduces the average annual pump energy consumption by about 12% compared with the "fixed ratio plus threshold frequency conversion" scheme. At the same time, the fluctuation of the hydraulic retention time of the deep purification reactor is reduced by about 10%, and the inactivation rate of anaerobic bacterial film is significantly reduced. This simultaneous improvement in the triple performance of "rapid peak shaving-low energy consumption-reactor stability" depends on the functional decoupling between the prediction loop and the proportional loop and the flow complementarity of the two physical purification pathways, which exceeds the expectations that can be intuitively deduced from single-loop threshold control or a single prediction-optimization method.

[0121] S3: Purify the water according to the hierarchical control strategy and return the purified water to the aquaculture pond.

[0122] Furthermore, in order to improve the stability of the long-term operation of the system, especially the microecological maintenance effect of the anaerobic reactor or denitrification unit in the lower deep purification path, a synchronous maintenance cycle is carried out based on the upper return water injection mechanism.

[0123] Specifically, during periods of low daily operating load (e.g., 2:00–2:30 a.m.), the system controller automatically identifies these low-load periods and initiates a synchronized maintenance cycle. The controller directs oxygen-enriched return water from the end of the upper rapid purification pathway through a dedicated three-way solenoid valve, injecting a proportional (1%–3%) amount of water into the lower pumping main. This return water, along with the bottom water from the aquaculture pond, flows into the front-end reactors (e.g., anaerobic reactors, denitrification units, etc.) of the lower purification pathway, creating a low-intensity, intermittent functional injection.

[0124] Unlike the addition of chemical reagents or periodic human intervention, the present invention utilizes upper layer treatment to complete the residual dissolved oxygen (<3mg / L), trace organic matter and nutrient factors in the water, and through ectopic injection, activates key functional bacteria such as denitrification bacteria and desulfurization bacteria that are in a suppressed state during long-term operation without destroying the anaerobic environment, thereby improving the activity of the reactor.

[0125] At the same time, with the help of the directional disturbance formed by the injected water flow, the internal flow structure of the reactor is improved, the dead zone deposition is broken, the physical blockage at the bottom is reduced, the continuous functional output of the reactor is maintained, and the fluctuation of purification performance caused by the decline of biofilm or the fluidization performance of the reactor is avoided.

[0126] The controller, in conjunction with the water quality sensing system, records and analyzes indicators such as dissolved oxygen, redox potential, ammonia nitrogen, and pH in the deep reaction zone before and after injection to determine whether the synchronized maintenance has achieved positive results. If water quality does not improve over multiple consecutive maintenance cycles, the system will automatically adjust the injection ratio or extend the injection interval to achieve intelligent regulation.

[0127] The low-energy, bio-friendly maintenance mechanism based on the self-circulation of internal purified water effectively replaces shutdown maintenance or strong intervention methods. It is suitable for scenarios such as sea cucumber ecological farming that have high requirements for system continuity and microecological stability.

[0128] In summary, the present invention, through the construction of an upper and lower layered pumping structure, a dual-path differentiated purification mechanism, and an adaptive synchronous maintenance strategy, not only achieves targeted, graded treatment of different types of pollution in sea cucumber aquaculture water, but also ensures the operational activity of the core reactor while taking into account the continuity of system operation and energy consumption control. This solution has the advantages of strong structural feasibility, high degree of operational automation, and low maintenance costs. It is particularly suitable for the high-density ecological aquaculture needs of benthic economic species such as sea cucumbers, and has significant practical value in improving the carrying capacity of unit water bodies and stabilizing the aquaculture water quality environment.

[0129] If the above functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the portion that contributes to the prior art, or the portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions for causing a computer device (which can be a personal computer, server, or network device, etc.) to execute all or part of the steps of the method described in each embodiment of the present invention. The aforementioned storage medium includes various media that can store program code, such as USB flash drives, mobile hard drives, read-only memories (ROMs), random access memories (RAMs), magnetic disks, or optical disks.

[0130] The logic and / or steps represented in the flowcharts or otherwise described herein, for example, can be considered as a sequenced list of executable instructions for implementing the logical functions, and can be embodied in any computer-readable medium for use by, or in conjunction with, an instruction execution system, apparatus, or device (e.g., a computer-based system, a system including a processor, or other system that can fetch and execute instructions from an instruction execution system, apparatus, or device). For purposes of this specification, a "computer-readable medium" can be any device that can contain, store, communicate, propagate, or transport a program for use by, or in conjunction with, an instruction execution system, apparatus, or device.

[0131] More specific examples (a non-exhaustive list) of computer-readable media include the following: an electrical connection with one or more wires (electronic devices), a portable computer disk cartridge (magnetic devices), a random access memory (RAM), a read-only memory (ROM), an erasable and programmable read-only memory (EPROM or flash memory), an optical fiber device, and a portable compact disc read-only memory (CDROM). In addition, the computer-readable medium may even be paper or other suitable medium on which the program is printed, since the program may be obtained electronically, for example, by optically scanning the paper or other medium, and then editing, interpreting, or processing in another suitable manner as necessary, and then storing it in a computer memory.

[0132] It should be understood that various components of the present invention may be implemented using hardware, software, firmware, or a combination thereof. In the aforementioned embodiments, multiple steps or methods may be implemented using software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented using hardware, as in another embodiment, any one or a combination of the following technologies known in the art may be used: a discrete logic circuit having logic gate circuits for implementing logic functions on data signals, an application-specific integrated circuit having suitable combinational logic gate circuits, a programmable gate array (PGA), a field-programmable gate array (FPGA), etc.

[0133] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the spirit and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A multi-stage filtration and purification method for ecological breeding of sea cucumbers, characterized in that: include: Establish two water purification channels: rapid purification channel and deep purification channel; The rapid purification channel includes a first water pumping port that draws upper layer water into the rapid purification channel; The water flows into the mechanical filtration device and the suspended solids are intercepted by the microporous filter and sand filter column; The filtered water flows into the UV sterilizer, which uses ultraviolet radiation to inactivate viruses and bacteria in the water; The sterilized water flows into the first biological filter tower, where it drips downwards. At the same time, oxygen exchange is active, which promotes the partial transformation of residual organic matter in the water by nitrifying and denitrifying bacteria, reducing oxygen consumption load. The purified water falls into the return water reservoir through the waterfall aeration plate, achieving rapid purification of the upper water; Collect water data from aquaculture ponds, determine stratification control strategies based on the data, and perform differentiated extraction of upper and lower water layers; Determining the hierarchical control strategy based on water body data includes calculating the vertical difference index of the water body data: ； ； ； in, Indicates the dissolved oxygen difference; Indicates the upper dissolved oxygen value; Indicates the dissolved oxygen value in the lower layer; Indicates the redox potential difference; represents the upper redox potential; represents the redox potential of the lower layer; Indicates the difference in ammonia nitrogen; Indicates the ammonia nitrogen concentration in the upper layer; Indicates the ammonia nitrogen concentration in the lower layer; Based on the aquaculture pond water data, the threshold of the vertical difference index is set, and the judgment logic is expressed as follows: ； Among them, Count means counting the number of true conditions in the brackets; Indicates the dissolved oxygen difference threshold; Indicates the redox potential difference threshold; Indicates the ammonia nitrogen difference threshold; When the judgment logic is met, it means that there is a stratified structure between the upper and lower water bodies. The upper water is purified through the rapid purification channel, and the lower water is purified through the deep purification channel. When the judgment logic is not satisfied, it means that there is no stratified structure between the upper and lower water bodies, and the lower water merges into the upper water and is uniformly purified through the rapid purification channel; Water is purified according to the hierarchical control strategy and the purified water is returned to the aquaculture pond.

2. The multi-stage filtration and purification method for a sea cucumber ecological breeding as claimed in claim 1, wherein: The deep purification channel includes a second water pumping port that pumps lower layer water into the deep purification channel; The lower layer of water enters the sedimentation device, where the particulate pollutants are settled under low flow conditions; The settled water enters the anaerobic reactor equipped with anaerobic granular sludge to biologically reduce the highly oxidized pollutants. The water flows into the denitrification device, where external carbon sources are dynamically added according to water quality parameters to strengthen the denitrification reaction and improve the removal efficiency of ammonia nitrogen; The water enters the composite adsorption device, which absorbs residual ammonia nitrogen, heavy metal ions and slightly toxic organic matter in the water in layers; The water enters the second biological filter, where the ammonia nitrogen and nitrite are biologically oxidized by the metabolism of nitrifying bacteria, and dissolved oxygen in the water is replenished; The water enters the dissolved air flotation tank, where microbubble technology is used to separate, float and remove particulate impurities, flocs and residual scum; The water enters the aerobic buffer tank to maintain the stability of water alkalinity, hardness and microecology; The purified water enters the return water reservoir to achieve deep purification of the lower layer of water.

3. A multi-stage filtration and purification method for sea cucumber ecological breeding as claimed in claim 1, characterized in that: The differential extraction of upper and lower water layers includes encapsulating water body data into a time window sequence and calculating the comprehensive water quality load index for the upper and lower water bodies respectively, which is expressed as: ； in, represents the water quality load index; i represents the i-th item of data; represents the weight coefficient; x i represents the measured value of the i-th water body data; T i represents the safety limit of the i-th water body data; Based on the water quality load index of the upper water body, the long short-term memory neural network is used to generate the upper load forecast value for the next 30 minutes , linearly map the upper load forecast value to obtain the total flow of the next control cycle: ； in, Indicates the total flow; Indicates the minimum flow rate to maintain circulation; k represents the linear amplification factor; Taking the load difference and dissolved oxygen difference between the upper and lower layers, and reasoning based on fuzzy logic rules, the output proportional coefficient controls the pumping multiple of the lower layer: ； in, represents the proportional coefficient; clip represents the restriction function; f represents the fuzzy inference function; Indicates the load difference between upper and lower layers; The double-stage incremental PID is used for flow regulation. First, the upper and lower pumping powers are adjusted to make the total flow meet the requirements. Under the premise of meeting the total flow rate, further fine-tune the upper and lower pumping power to make the flow rate ratio close to the target value. .

4. A multi-stage filtration and purification device for ecological aquaculture of sea cucumbers, used to perform a multi-stage filtration and purification method for ecological aquaculture of sea cucumbers according to any one of claims 1 to 3, characterized in that: include: A breeding pond, wherein the breeding pond is provided with a first water extraction port for extracting upper layer water and a second water extraction port for extracting lower layer water; A rapid purification channel, the rapid purification channel sequentially comprising a primary filtration device and a first biological filter tower, the water inlet of the rapid purification channel being connected to the first water pumping port, and the water outlet being returned to the aquaculture pond; A deep purification channel, which includes a sedimentation device, an anaerobic reactor, a denitrification device, a composite adsorption device, a second biological filter, a dissolved air flotation tank and an aerobic buffer tank in sequence, wherein the water inlet of the deep purification channel is connected to the second water pumping port, and the water outlet is returned to the aquaculture pond; A water quality sensing system, installed at the first water inlet and the second water inlet, for collecting water data of the aquaculture pond; A controller is electrically connected to the water quality sensing system, the rapid purification channel and the deep purification channel respectively, determines whether there is pollution stratification in the water body according to the water body data, and controls the operating status and flow ratio of the first water pumping port and the second water pumping port.

5. A multi-stage filtration and purification device for ecological breeding of sea cucumbers as claimed in claim 4, characterized in that: The first water pumping port and the second water pumping port are interconnected through a connecting pipe, and three-way valves are provided at both ends of the connecting pipe, and the three-way valves are controlled by a controller; The water outlet end of the rapid purification channel is connected to the second water pumping port, which is used to send the return water of the rapid purification channel to the deep purification channel.

6. A multi-stage filtration and purification device for ecological breeding of sea cucumbers as claimed in claim 5, characterized in that: The primary filtration device includes a mechanical filtration device and an ultraviolet sterilization device. A waterfall aeration plate is set at the end of the first biological filter tower, and the height of the first biological filter tower itself is used to aerate and oxygenate the return water. The return water falls into the return water reservoir and is injected into the breeding pond through the return pipe.

Images