Device and method for treating mariculture wastewater

Abstract

The invention provides a device and a method for treating mariculture wastewater, and belongs to the technical field of wastewater treatment. The device for treating the mariculture wastewater comprises an air micro-nano bubble generating device, air micro-nano bubble treatment equipment, an ozone micro-nano bubble generating device and ozone micro-nano bubble treatment equipment which are sequentially arranged from left to right, the interior of the air micro-nano bubble generation device is communicated with the interior of the air micro-nano bubble treatment equipment through a water outlet pipeline A. The interior of the air micro-nano bubble treatment equipment is communicated with the interior of the ozone micro-nano bubble generation device through a water outlet pipeline B. The interior of the ozone micro-nano bubble generation device is communicated with the interior of the ozone micro-nano bubble treatment equipment through a water outlet pipeline C; the method is used for solving the technical problems that soluble pollutants are difficult to remove and secondary pollution is easy to generate in the prior art, and wastewater can be treated under the condition that no medicament is used.

Description

Technical Field

[0001] The present invention belongs to the technical field of wastewater treatment, and in particular relates to a device and method for treating marine aquaculture wastewater. Background Art

[0002] With the rapid development of marine aquaculture, eutrophication in coastal waters caused by the discharge of aquaculture wastewater is becoming increasingly serious. This wastewater contains high concentrations of leftover bait, feces, antibiotics, and nitrogen and phosphorus pollutants, and its salinity is often as high as 20-35‰. This inhibits the activity of microorganisms in traditional biological treatment processes, significantly reducing treatment efficiency.

[0003] In the prior art, physical filtration methods have difficulty removing soluble pollutants. For example, the invention with authorization number CN111217500B discloses a wastewater treatment device for aquaculture seawater. Under the action of an impurity removal mechanism, the filter screen with adhered impurities can be replaced and the mesh of the filter screen with adhered impurities can be dredged. Chemical flocculation methods have the disadvantages of high reagent costs and easy secondary pollution. For example, the invention patent with publication number CN107055889A discloses a high-efficiency electrolytic denitrification and dephosphorization device for marine aquaculture wastewater. After the nitrogen and phosphorus in the wastewater are electrolytically released through the electrolysis device anode, electrolysis device cathode, and dosing pipeline, a precipitate is generated through the dosing and mixing reaction.

[0004] In view of the above-mentioned problems, the present invention provides a device and method for treating marine aquaculture wastewater, which can treat the wastewater without using any chemicals. Summary of the Invention

[0005] Therefore, the present invention provides a device and method for treating seawater aquaculture wastewater, which is used to solve the technical problems that the existing technology is difficult to remove soluble pollutants and is prone to secondary pollution.

[0006] The present invention is achieved in that:

[0007] The present invention provides a device for treating marine aquaculture wastewater, which includes an air micro-nano bubble generating device, an air micro-nano bubble treatment device, an ozone micro-nano bubble generating device, and an ozone micro-nano bubble treatment device, which are arranged in sequence from left to right. The interiors of the air micro-nano bubble generating device and the air micro-nano bubble treatment device are connected via a water outlet pipe A, the interiors of the air micro-nano bubble treatment device and the ozone micro-nano bubble generating device are connected via a water outlet pipe B, and the interiors of the ozone micro-nano bubble generating device and the ozone micro-nano bubble treatment device are connected via a water outlet pipe C.

[0008] The left side of the air micro-nano bubble generating device is fixedly connected to an air inlet pipe A and a water inlet pipe A which are arranged longitudinally and are respectively connected to the interior of the air micro-nano bubble generating device. The ozone micro-nano bubble generating device is connected to an ozone generating device through an air inlet pipe C.

[0009] On the basis of the above technical solution, the device for treating marine aquaculture wastewater of the present invention can also be improved as follows:

[0010] Furthermore, one end of a sludge discharge pipeline fixedly connected and communicated with the interior of the air micro-nano bubble treatment device is provided on the upper left side thereof, and the other end of the sludge discharge pipeline extends into the sludge collection device.

[0011] Furthermore, the ozone micro-nano bubble treatment device and the interior of the air intake pipe A are connected via an ozone recycling pipe;

[0012] An ultraviolet lamp group is provided inside the ozone micro-nano bubble treatment device. The right side of the ozone micro-nano bubble treatment device is connected to a water outlet collection device through a water outlet pipe D. The right end of the water outlet collection device is connected to a drain pipe.

[0013] Further, based on any one of claims 1 to 3, the method comprises the following steps:

[0014] S1: Take samples of actual wastewater from marine aquaculture farms and conduct water quality testing;

[0015] S2: passing the obtained actual wastewater into the air micro-nano bubble generating device to form air micro-nano bubbles in the wastewater solution;

[0016] S3: passing the wastewater solution mixed with air micro-nano bubbles into the air micro-nano bubble treatment equipment for treatment, and adjusting the reaction conditions according to the concentration of pollutants;

[0017] S4: The wastewater treated by the air micro-nano bubble treatment device is passed into the ozone micro-nano bubble generating device to form ozone micro-nano bubbles in the wastewater solution;

[0018] S5: The wastewater solution mixed with ozone micro-nano bubbles is passed into the ozone micro-nano bubble treatment equipment, and the reaction conditions are adjusted according to the concentration of pollutants;

[0019] S6: Discharge tailwater up to standard and make resource utilization of discharged sludge.

[0020] Furthermore, the S1 specifically includes:

[0021] S11: Take 30L of actual wastewater from a marine aquaculture farm and filter it through a non-woven fabric filter with a pore size of 5mm×5mm;

[0022] S12: Conduct water quality testing on the filtered wastewater to obtain the types and concentrations of pollutants.

[0023] Furthermore, the S2 specifically includes:

[0024] S21: The actual wastewater obtained in step S1 enters the air micro-nano bubble generating device through the water inlet pipe A, where the water inlet flow rate Q1 is 15 L / h;

[0025] S22: supplying gas with a set pressure into the air micro-nano bubble generating device through the air inlet pipe A and the air pump A, wherein the pressure value range is 0.1MPa-0.3MPa;

[0026] S23: The air and the wastewater solution are mixed in the air micro-nano bubble generating device 1, thereby forming air micro-nano bubbles in the wastewater solution;

[0027] S24: The wastewater solution mixed with air micro-nano bubbles is input into the air micro-nano bubble treatment equipment through the outlet pipe A.

[0028] Furthermore, the S3 specifically includes:

[0029] S31: According to the concentration of suspended particulate matter obtained in S12, the air inlet flow rate Q2 of the air micro-nano bubble processing device is adjusted to make the air inlet flow rate Q2 of the air micro-nano bubble generating device 1 = 52m 3 / L;

[0030] S32: Suspended particulate matter and the like are discharged through the sludge discharge pipeline of the air micro-nano bubble treatment equipment, and the discharged sludge is collected in the sludge collection device and recycled as a resource.

[0031] Furthermore, the S4 specifically includes:

[0032] S41: The water treated by the air micro-nano bubble treatment device enters the ozone micro-nano bubble generating device through the outlet pipe B, and is used to generate ozone through the air pump C and the ozone generating device connected to the air inlet pipe C;

[0033] S42: The ozone and the effluent water solution of the air micro-nano bubble treatment device are mixed in the ozone micro-nano bubble generating device, thereby forming ozone micro-nano bubbles in the wastewater solution;

[0034] S43: The wastewater solution mixed with ozone micro-nano bubbles is input into the ozone micro-nano bubble treatment equipment through the outlet pipe C.

[0035] Furthermore, the S5 specifically includes:

[0036] S51: adjusting the air inlet flow and ozone concentration of the ozone micro-nano bubble treatment equipment according to the pollutant concentration;

[0037] S52: The ozone micro-nano bubble treatment equipment contains a set of UV lamps, and the number of lamps in operation is controlled according to the concentration of pollutants;

[0038] S53: An ozone recycling pipeline is installed on the upper part of the ozone micro-nano bubble treatment equipment to recover ozone tail gas from bottom to top and re-inject it into the air micro-nano bubble generating device to achieve the recycling of ozone;

[0039] S54: The water treated with ozone micro-nano bubbles enters the water collection device through the water outlet pipe D;

[0040] S55: drain the water in the water collection device through the drain pipe.

[0041] Compared with the prior art, the device and method for treating marine aquaculture wastewater provided by the present invention have the following beneficial effects:

[0042] This invention leverages the high specific surface area, long-lasting residence time, and interfacial charge characteristics of micro-nano bubbles to significantly improve gas-liquid mass transfer efficiency, thereby significantly increasing the utilization rate of ozone and oxygen. The air micro-nano bubble device first removes suspended matter through flotation and performs preliminary oxidation, achieving energy savings of 40%-50% compared to traditional flotation methods while also reducing the processing burden of subsequent ozone units. The ozone device is specifically designed to degrade difficult-to-degrade pollutants, with a clear two-stage process division of labor, significantly reducing energy consumption compared to traditional mixed treatment processes.

[0043] Micro-nano bubbles carry a negative surface charge, which electrostatically attracts suspended particles and reduces the need for chemical coagulants. Due to their high surface area, micro-nano bubbles are highly effective in absorbing tiny suspended particles in wastewater, such as leftover bait, fecal debris, and colloidal organic matter. Furthermore, to address the problem of oil and fat contaminants in marine aquaculture wastewater, micro-nano bubbles can directly separate oil from water through interfacial adsorption, effectively overcoming the limitation of traditional flotation technology that requires the addition of demulsifiers.

[0044] This invention utilizes the synergistic effect of ozone micro-nanobubbles and ultraviolet light to catalyze the decomposition of ozone to produce hydroxyl radicals, which, combined with chloride ions in seawater, generate active substances such as hypochlorous acid, thereby constructing a multi-dimensional oxidation network. This innovation significantly improves the removal efficiency of difficult-to-degrade organic pollutants, increasing the reaction rate by over 50% compared to traditional single oxidation technologies (such as ozone aeration alone).

[0045] In response to the high-salinity and difficult-to-treat characteristics of seawater wastewater, the present invention innovatively utilizes the catalytic effect of chloride ions in a UV / ozone system to generate highly oxidizing hypochlorous acid free radicals (ClO·). This allows for deep degradation of pollutants without the need for additional chemical agents, thus overcoming the bottleneck of low efficiency of traditional technologies in treating high-salinity wastewater.

[0046] This method relies entirely on physical flotation and free radical oxidation mechanisms, thus avoiding the secondary water pollution that can be caused by traditional chemical demulsifiers and oxidants. Furthermore, by recycling ozone tail gas and reinjecting it into the air micro-nano bubble device, ozone recycling is achieved, effectively avoiding the secondary pollution caused by direct ozone emissions in traditional processes and reducing ozone usage costs.

[0047] By scientifically controlling ozone oxidation conditions, active substances such as hydroxyl radicals can more effectively contact reducing substances and microorganisms in wastewater, effectively improving ozone utilization and reducing ozone consumption rate, and can efficiently reduce the concentration of pollutants such as COD and NH3-N in wastewater in the absence of catalysts. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] 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 embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0049] Figure 1 is a schematic diagram of a device for treating marine aquaculture wastewater;

[0050] Figure 2 Before and after comparison of wastewater treatment;

[0051] Figure 3 Comparison of the treatment effects of air micro-nano bubble flotation and traditional flotation;

[0052] In the accompanying drawings, the components represented by the reference numerals are as follows:

[0053] 1. Air micro-nano bubble generator; 11. Air inlet pipe A; 12. Water inlet pipe A; 13. Water outlet pipe A; 14. Air pump A; 2. Air micro-nano bubble treatment equipment; 21. Sludge discharge pipe; 22. Water outlet pipe B; 23. Sludge collection device; 3. Ozone micro-nano bubble generator; 31. Air inlet pipe C; 32. Ozone generator; 33. Water outlet pipe C; 34. Air pump C; 4. Ozone micro-nano bubble treatment equipment; 41. Ozone reuse pipe; 42. Water outlet pipe D; 43. UV lamp assembly; 44. Water outlet collection device; 45. Drain pipe. DETAILED DESCRIPTION

[0054] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0055] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention as claimed, but rather merely represents selected embodiments of the present invention. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are also within the scope of protection of the present invention.

[0056] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0057] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like to indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0058] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature identified as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, "plurality" means two or more, unless otherwise specifically defined.

[0059] Example 1

[0060] like Figure 1As shown, the present invention provides a device for treating marine aquaculture wastewater, which includes, from left to right, an air micro-nano bubble generating device 1, an air micro-nano bubble treatment device 2, an ozone micro-nano bubble generating device 3, and an ozone micro-nano bubble treatment device 4. The interiors of the air micro-nano bubble generating device 1 and the air micro-nano bubble treatment device 2 are connected via an outlet pipe A13, the interiors of the air micro-nano bubble treatment device 2 and the ozone micro-nano bubble generating device 3 are connected via an outlet pipe B22, and the interiors of the ozone micro-nano bubble generating device 3 and the ozone micro-nano bubble treatment device 4 are connected via an outlet pipe C33.

[0061] The left side of the air micro-nano bubble generating device 1 is fixedly connected to an air inlet pipe A11 and a water inlet pipe A12 which are arranged longitudinally and are respectively connected to the interior thereof. The ozone micro-nano bubble generating device 3 is connected to an ozone generating device 32 via an air inlet pipe C31.

[0062] Optionally, in the above technical solution, one end of a sludge discharge pipeline 21 is fixedly connected to and communicated with the interior of the air micro-nano bubble treatment device 2 and the other end of the sludge discharge pipeline 21 extends into the sludge collection device 23 .

[0063] Optionally, in the above technical solution, the ozone micro-nano bubble treatment device 4 and the inside of the air intake pipe A11 are connected through the ozone recycling pipe 41;

[0064] An ultraviolet lamp group 43 is provided inside the ozone micro-nano bubble treatment device 4. The right side of the ozone micro-nano bubble treatment device 4 is connected to a water outlet collection device 44 through a water outlet pipe D42. The right end of the water outlet collection device 44 is connected to a drain pipe 45.

[0065] Furthermore, the other end of the drain pipe is connected to a water treatment tail device.

[0066] Furthermore, one-way valves are provided on the pipelines, and the opening and closing of the one-way valves can be controlled so that the processed mud and water can only flow in one direction; for example, the one-way valves are opened in sequence, and when one one-way valve is opened, the other one-way valves are closed.

[0067] Furthermore, the water treatment tail-end device includes activated carbon adsorption, membrane components, etc., which can be further processed in depth and discharged at higher standards.

[0068] The water supply flow rate of the outlet pipe A13 is consistent with the drainage flow rate of the outlet pipe D42, that is, the total amount of water and the residence time in the device are relatively stable. A method for treating marine aquaculture wastewater is based on any one of claims 1-3, wherein the method comprises the following steps:

[0069] S1: Take samples of actual wastewater from marine aquaculture farms and conduct water quality testing;

[0070] S2: passing the obtained actual wastewater into the air micro-nano bubble generating device 1 to form air micro-nano bubbles in the wastewater solution;

[0071] S3: passing the wastewater solution mixed with air micro-nano bubbles into the air micro-nano bubble treatment device 2 for treatment, and adjusting the reaction conditions according to the concentration of pollutants;

[0072] S4: The wastewater treated by the air micro-nano bubble treatment device 2 is passed into the ozone micro-nano bubble generating device 3 to form ozone micro-nano bubbles in the wastewater solution;

[0073] S5: The wastewater solution mixed with ozone micro-nano bubbles is passed into the ozone micro-nano bubble treatment device 4, and the reaction conditions are adjusted according to the concentration of pollutants;

[0074] S6: Discharge the tail water that meets the standards and make resource utilization of the discharged sludge.

[0075] Optionally, in the above technical solution, S1 specifically includes:

[0076] S11: Take 30L of actual wastewater from a marine aquaculture farm and filter it through a non-woven fabric filter with a pore size of 5mm×5mm;

[0077] S12: Conduct water quality testing on the filtered wastewater to obtain the types and concentrations of pollutants.

[0078]

[0079] Among them, suspended solids, chemical oxygen demand, and total nitrogen are detected by the water quality monitoring and analysis method in the "Shandong Province Marine Aquaculture Tail Water Discharge Standard (DB374676-2023)", and antibiotics are detected by high performance liquid chromatography (preferably, the high performance liquid chromatograph adopts D-7000HITACHI);

[0080] Optionally, in the above technical solution, S2 specifically includes:

[0081] S21: The actual wastewater obtained in step S1 enters the air micro-nano bubble generating device 1 through the water inlet pipe A12, where the water inlet flow rate Q1 is 15 L / h;

[0082] S22: supplying gas with a set pressure into the air micro-nano bubble generating device 1 through the air inlet pipe A11 and the air pump A14, wherein the pressure value range is 0.1MPa-0.3MPa;

[0083] S23: The air and the wastewater solution are mixed in the air micro-nano bubble generating device 1, thereby forming air micro-nano bubbles in the wastewater solution;

[0084] S24: The wastewater solution mixed with air micro-nano bubbles is input into the air micro-nano bubble treatment device 2 through the outlet pipe A13;

[0085] Optionally, in the above technical solution, S3 specifically includes:

[0086] S31: According to the concentration of suspended particulate matter obtained in S12, the air inlet flow rate Q2 of the air micro-nano bubble processing device 2 is adjusted using the following formula:

[0087]

[0088] Q(SS) is the intake air flow rate. Based on the SS concentration measured in step S1, it is substituted into formula 1, so the intake air flow rate of the air micro-nano bubble generating device 1 is Q2 = 52m 3 / L,

[0089] S32: Suspended particles, fat particles, etc. are discharged through the sludge discharge pipe 21 of the air micro-nano bubble treatment device 2, and the discharged sludge is collected in the sludge collection device 23 for resource utilization;

[0090] Air micro-nano bubbles can generate highly oxidizing hydroxyl radicals, and dissolved organic pollutants, ammonia nitrogen, etc. are pre-oxidized in the air micro-nano bubble treatment equipment 2;

[0091] Optionally, in the above technical solution, S4 specifically includes:

[0092] S41: The water treated by the air micro-nano bubble treatment device 2 enters the ozone micro-nano bubble generator 3 through the outlet pipe B22, and generates ozone through the air pump C34 and the ozone generator 32 connected to the air inlet pipe C31;

[0093] S42: The ozone and the effluent water solution of the air micro-nano bubble treatment device 2 are mixed in the ozone micro-nano bubble generating device 3, thereby forming ozone micro-nano bubbles in the wastewater solution;

[0094] S43: The wastewater solution mixed with ozone micro-nano bubbles is input into the ozone micro-nano bubble treatment device 4 through the outlet pipe C33;

[0095] Optionally, in the above technical solution, step S5 specifically includes:

[0096] S51: adjusting the air flow rate and ozone concentration of the ozone micro-nano bubble treatment device 4 according to the pollutant concentration;

[0097] The ozone concentration is adjusted by the ozone generating device 32 , and the air intake flow is adjusted by the ozone micro-nano bubble generating device 3 .

[0098] The specific ozone concentration is:

[0099] 1) Real-time acquisition of COD, NH3-N and salinity data in wastewater through online sensors;

[0100] 2) Based on the preset COD and ammonia nitrogen-ozone dose response curves, calculate the theoretical ozone demand D COD and

[0101] 2.1) The COD-ozone dosage model is as follows:

[0102]

[0103] Further we get:

[0104]

[0105] Where: η COD : COD removal rate (%);

[0106] D: ozone dose (mg O3 / mg COD);

[0107] Among them, ozone dose refers to the amount of ozone required to degrade each milligram of pollutants;

[0108] k COD : reaction rate constant;

[0109] The exponential relationship between COD removal rate and ozone dosage was determined by batch experiments, and its rate constant k COD Corrected by salinity S(‰): k COD =1.2×(1-0.008×S); when salinity S=35‰, the actual k COD =1.2×(1-0.008×35)=0.864.

[0110] The specific batch experiment steps are as follows:

[0111] Experimental materials and equipment raw water configuration:

[0112] Simulating marine aquaculture wastewater, the salinity gradient was 0‰, 20‰, 35‰, and 40‰ (adjusted by NaCl), and the initial COD concentration was uniformly set at 200 mg / L;

[0113] Ozone generator: Ozone concentration range is 5-20mg / L, flow rate is adjustable;

[0114] Micro-nano bubble reactor: volume 10L, bubble diameter 100-200nm;

[0115] Testing instruments: COD rapid tester, salinity meter, ozone concentration detector.

[0116] Experimental steps:

[0117] Step 1: Salinity grouping and reaction system construction,

[0118] Four groups of wastewater with salinity (0‰, 20‰, 35‰, 40‰) were prepared, and five ozone dosage gradients (D = 0.5, 1.0, 1.5, 2.0, 2.5 g O3 / g COD) were set in each group;

[0119] Each experiment was repeated three times, and the temperature was controlled at 25±1°C and the pH was adjusted to 7.0±0.2 (phosphate buffer solution).

[0120] Step 2: Ozone addition and reaction,

[0121] Inject wastewater into the reactor, turn on the ozone generator and micro-nano bubble device, add ozone according to the preset dosage, and the reaction time is 30 minutes.

[0122] Samples were taken every 5 minutes to detect the residual COD concentration in the water (a total of 6 time points in each group).

[0123] Step 3: Data recording and model fitting,

[0124] Calculate the COD removal rate at each time point:

[0125]

[0126] Use nonlinear regression method to fit the following formula to obtain k under different salinities COD value

[0127]

[0128] Step 4: Establishment of salinity correction model,

[0129] The salinity of each group (S) and the corresponding k COD Perform linear regression and obtain the correction formula:

[0130] k COD =1.2×(1-0.008·S) (Formula 5)

[0131] Based on the Shandong Province Marine Aquaculture Tailwater Discharge Standard (DB37 4676-2023), the present invention takes the first-level discharge standard (COD ≤ 10 mg / L) as the target discharge concentration and substitutes it into formula 2 to calculate D COD =2.2mg O3 / mg COD.

[0132] Among them, Cactual is the actual water body index measured in S12: COD-67; CTarget is the first-level emission index COD-10 in the Shandong Province Marine Aquaculture Emission Standard.

[0133] 2.2) The ammonia nitrogen-ozone dosage model is as follows:

[0134]

[0135] Further:

[0136]

[0137] NH3-N removal rate (%);

[0138] Half-saturation constant

[0139] NH3-N removal follows the Michaelis-Menten equation, with a half-saturation constant of Negatively correlated with temperature T(℃)

[0140]

[0141] When the temperature T = 25℃,

[0142] The present invention is based on the first-level discharge standard (TN≤4mg / L) of the Shandong Province Marine Aquaculture Tail Water Discharge Standard (DB37 4676-2023). Based on step S1 (the table of S12 shows that TN is 7mg / L and NH3-N is 3.5mg / L, which accounts for the largest proportion of nitrogen content and is half of TN), it can be seen that NH3-N is the main nitrogen pollutant in wastewater. Therefore, the present invention sets the target concentration of NH3-N≤2mg / L and substitutes it into formula 6 to calculate: mgO3 / mgNH3-N.

[0143] Among them, C is actually the actual water body index measured in S12: ammonia nitrogen -67; the first-level emission index in Shandong Province's marine aquaculture emission standard is total nitrogen -4, and the C target is not more than half of the total nitrogen, taking NH3-N ≤ 2 mg / L.

[0144] 3) Take As the final ozone dosage reference value, the ozone dosage reference value is 2.20.;

[0145] 4) Correct Dmax based on real-time salinity and temperature data:

[0146] Dactual = Dmax × [1 + 0.005 × (S-35)] × [1 + 0.015 × (T-25)] (Dmax is D COD The value is 2.2. According to the salinity of the next row, 35 and T25, S=35 and T=25 in this row, the calculated Dactual=2.2*1.175*1.375=3.55);

[0147] The present invention is implemented at a salinity of 35‰ and T = 25°C. Based on the above formula, D actual = 3.55;

[0148] According to formula M 臭氧总量 =D 实际 ×(C 实际 -C 目标 ), M 臭氧总量 =3.55*57mg=202.35mg O3 / L, the water flow rate Q1 is 15L / h;

[0149] Among them, Cactual is the actual water body index measured in S12: COD-67; CTarget is the first-level emission index in Shandong Province's marine aquaculture emission standards: COD-10.

[0150] 5) Adjust the ozone generator output ozone concentration to C = 14.25 mg / L and the air flow Q2 = 60 L / h, so that M 臭氧总量 ×Q1=C×Q2, according to the above, we can get M 臭氧总量 =202.35 and Q1=15, C=50.5875, which means real-time matching of ozone dosage is achieved.

[0151] S52: The ozone micro-nano bubble treatment device 4 contains an array of ultraviolet lamps 43, and the number of lamps in operation can be controlled according to the concentration of pollutants;

[0152] a) The front, middle and rear UV lamp groups are distributed in sequence from bottom to top along the water flow direction of the reactor, and the power of each lamp group is independently controllable;

[0153] b) Obtain COD and NH3-N data at the water inlet, middle section and outlet in real time based on online sensors;

[0154] c) Control logic: When the COD at the water inlet is ≥90mg / L, the front section light group operates at full power, the middle section light group operates at 60% power, and the rear section light group is turned off; when the COD at the water outlet is ≤30mg / L, the power of the front section light group is reduced to 40%, the middle section is turned off, and the rear section light group operates at 30% power; the power of each section light group decays linearly with the decrease in pollutant concentration, and the decay rate does not exceed 5% / min.

[0155] S53: An ozone recycling pipeline 41 is provided on the upper part of the ozone micro-nano bubble treatment device 4 to recover ozone tail gas from bottom to top and re-inject it into the air micro-nano bubble generating device 1 to achieve the recycling of ozone;

[0156] S54: The water treated with ozone micro-nano bubbles enters the water collection device 44 through the water outlet pipe D42;

[0157] S55: drain the water in the water collection device through the drain pipe 45.

[0158] like Figure 2 As shown, this device and method demonstrate significant advantages in treating marine aquaculture wastewater: Leveraging the efficient mass transfer characteristics of micro-nanobubbles, ozone dissolution efficiency is increased severalfold. Combined with the strong oxidizing effect of OH, it achieves efficient removal of COD and NH3-N by 88.1% and 85.7% respectively. Simultaneously, the flotation effect of the micro-nanobubbles is also utilized, resulting in a 74.6% SS removal rate and an increase in effluent dissolved oxygen to 8-10 mg / L, achieving both water oxygenation and disinfection. The treated effluent meets the Class I discharge standards for SS, COD, NH3-N, and TN in the Shandong Province Marine Aquaculture Tailwater Discharge Standard (DB37 4676-2023).

[0159] In Experiments 1-3, the raw water used was actual wastewater from a marine aquaculture farm and filtered through a 5 mm x 5 mm pore size filter. For each 15 L raw water solution, the raw water quality conditions were: SS = 130 mg / L, COD = 67 mg / L, NH₃-N = 3.5 mg / L, TN = 7 mg / L, salinity = 35‰, pH = 7.2, and temperature = 25°C.

[0160] Experimental Example 1

[0161] In the air micro-nano bubble treatment device 1, compared with the traditional aeration method flotation, the air micro-nano bubble flotation has a significantly improved treatment effect in removing suspended solids (SS) in raw water, such as Figure 3 As shown in the figure, traditional large-scale bubble flotation technology achieves a SS removal rate of only 40%, far below effluent standards and requiring the addition of additional chemicals. In contrast, air micro-nanobubbles, due to their larger specific surface area and longer residence time, significantly increase SS removal to 94.4% by enhancing gas-solid adsorption (i.e., adsorption of solid impurities in the wastewater by the bubbles). This eliminates the need for additional chemicals (excessive nanobubble concentrations are harmless or polluting, whereas excessive chemical concentrations can). Effluent standards can be met solely through treatment with air, ozone, micro-nanobubbles, and other agents.

[0162] Experimental Example 2

[0163] To further verify the technical advancement and engineering feasibility of the present invention, a comparison was conducted with single ozone oxidation in the ozone micro-nano bubble treatment device 3. The specific experimental groups are as follows:

[0164] a. Ozone (O3) alone: ​​ozone concentration = 15 mg / L, traditional aeration (bubble diameter > 1 mm);

[0165] b. Ozone micro-nano bubbles (O3-MNB): ozone concentration = 15 mg / L, bubble diameter = 100-200 nm;

[0166] c. Ozone + UV (O3 + UV): ozone concentration = 15 mg / L, UV lamp (254 nm, power = 300 W);

[0167] d. Ozone micro-nano bubbles + ultraviolet (O3-MNB+UV): ozone concentration = 15 mg / L, bubble diameter = 100-200 nm, ultraviolet lamp (254 nm, power = 300 W).

[0168] The ozone inlet flow rate was 500 mL / min, the hydraulic retention time was 30 minutes, and the reactor volume was 15 L.

[0169] The processing results are shown in the following table:

[0170]

[0171] The ozone micro-nanobubble system significantly improves ozone utilization by increasing the gas-liquid contact area (three times that of traditional ozone), raising the COD removal rate from 26.9% to 86.6%. The ozone + ultraviolet synergy (O3-MNB+UV) directly decomposes organic molecules with ultraviolet light and stimulates ozone to produce high concentrations of hydroxyl radicals (·OH up to 18.3μM), resulting in COD and NH3-N removal rates of 92.5% and 91.4%, respectively. This method also produces no secondary pollution, and ozone decomposes into oxygen without chemical residues, making it suitable for recirculating aquaculture.

[0172] Experimental Example 3

[0173] Because marine aquaculture wastewater contains relatively high concentrations of antibiotic residues, the present invention was further tested for its effectiveness in removing residual antibiotics. The raw water contained 26 μg / L of sulfamethoxazole and 67 μg / L of oxytetracycline. The ozone inlet flow rate was 500 mL / min, the inlet concentration was 15 mg / L, the hydraulic downtime was 30 minutes, and the reactor volume was 15 L.

[0174] The treatment effects are shown in the following table:

[0175]

[0176] The present invention significantly improves ozone's mass transfer efficiency, achieving removal rates of 98.2% for sulfamethoxazole and 96.4% for oxytetracycline, respectively. This represents a 30% to 35% improvement compared to ozone treatment alone. Furthermore, ultraviolet light excites ozone, generating high concentrations of hydroxyl radicals that significantly mineralize the antibiotics, reducing their toxic equivalents by 94.7%.

[0177] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A device for treating marine aquaculture wastewater, characterized in that: The invention comprises an air micro-nano bubble generating device (1), an air micro-nano bubble processing device (2), an ozone micro-nano bubble generating device (3) and an ozone micro-nano bubble processing device (4) which are arranged in sequence from left to right. The interiors of the air micro-nano bubble generating device (1) and the air micro-nano bubble processing device (2) are connected via a water outlet pipe A (13), the interiors of the air micro-nano bubble processing device (2) and the ozone micro-nano bubble generating device (3) are connected via a water outlet pipe B (22), and the interiors of the ozone micro-nano bubble generating device (3) and the ozone micro-nano bubble processing device (4) are connected via a water outlet pipe C (33); The left side of the air micro-nano bubble generating device (1) is fixedly connected to an air inlet pipe A (11) and a water inlet pipe A (12) which are arranged longitudinally and are respectively connected to the interior of the air micro-nano bubble generating device (1), and the ozone micro-nano bubble generating device (3) is connected to an ozone generating device (32) via an air inlet pipe C (31).

2. The device for treating marine aquaculture wastewater according to claim 1, characterized in that: One end of a mud discharge pipeline (21) is fixedly connected to and communicated with the interior of the air micro-nano bubble treatment device (2) and is provided on the upper left side of the device. The other end of the mud discharge pipeline (21) extends into a sludge collection device (23).

3. The device for treating marine aquaculture wastewater according to claim 2, characterized in that: The ozone micro-nano bubble treatment device (4) and the interior of the air inlet pipeline A (11) are connected via an ozone recycling pipeline (41); An ultraviolet lamp group (43) is provided inside the ozone micro-nano bubble treatment device (4), and the right side of the ozone micro-nano bubble treatment device (4) is connected to a water outlet collection device (44) through a water outlet pipe D (42), and the right end of the water outlet collection device (44) is connected to a drain pipe (45).

4. A method for treating marine aquaculture wastewater according to claim 1, characterized in that: The method according to any one of claims 1 to 3 is characterized in that it comprises the following steps: S1: Take samples of actual wastewater from marine aquaculture farms and conduct water quality testing; S2: passing the obtained actual wastewater into the air micro-nano bubble generating device (1), and forming air micro-nano bubbles in the wastewater solution; S3: passing the wastewater solution mixed with air micro-nano bubbles into the air micro-nano bubble treatment device (2) for treatment, and adjusting the reaction conditions according to the concentration of pollutants; S4: the wastewater treated by the air micro-nano bubble treatment device (2) is passed into the ozone micro-nano bubble generating device (3), so that ozone micro-nano bubbles are formed in the wastewater solution; S5: The wastewater solution mixed with ozone micro-nano bubbles is passed into the ozone micro-nano bubble treatment device (4), and the reaction conditions are adjusted according to the concentration of pollutants; S6: Discharge tailwater up to standard and make resource utilization of discharged sludge.

5. A method for treating marine aquaculture wastewater according to claim 4, characterized in that: Said S1 specifically includes: S11: Take 30L of actual wastewater from a marine aquaculture farm and filter it through a non-woven fabric filter with a pore size of 5mm×5mm; S12: Conduct water quality testing on the filtered wastewater to obtain the types and concentrations of pollutants.

6. A method for treating marine aquaculture wastewater according to claim 5, characterized in that: The S2 specifically includes: S21: The actual wastewater obtained in step S1 enters the air micro-nano bubble generating device (1) through the water inlet pipe A (12), where the water inlet flow rate Q1 is 15 L / h; S22: supplying gas with a set pressure into the air micro-nano bubble generating device (1) through the air inlet pipe A (11) and the air pump A (14), wherein the pressure value range is 0.1MPa-0.3MPa; S23: air and wastewater solution are mixed in the air micro-nano bubble generating device (1), thereby forming air micro-nano bubbles in the wastewater solution; S24: The wastewater solution mixed with air micro-nano bubbles is input into the air micro-nano bubble treatment device (2) through the outlet pipe A (13).

7. A method for treating marine aquaculture wastewater according to claim 6, characterized in that: The S3 specifically includes: S31: According to the concentration of suspended particulate matter obtained in S12, the air intake flow rate Q2 of the air micro-nano bubble processing device (2) is adjusted to make the air intake flow rate Q2 of the air micro-nano bubble generating device (1) = 52m 3 / L; S32: Suspended particles and the like are discharged through the sludge discharge pipe (21) of the air micro-nano bubble treatment device (2), and the discharged sludge is collected in the sludge collection device (23) and recycled.

8. A method for treating marine aquaculture wastewater according to claim 7, characterized in that: The S4 specifically includes: S41: The water treated by the air micro-nano bubble treatment device (2) enters the ozone micro-nano bubble generating device (3) through the water outlet pipe B (22), and is used to generate ozone through the air pump C (34) and the ozone generating device (32) connected to the air inlet pipe C (31); S42: The ozone and the effluent water solution of the air micro-nano bubble treatment device (2) are mixed in the ozone micro-nano bubble generating device (3), thereby forming ozone micro-nano bubbles in the wastewater solution; S43: The wastewater solution mixed with ozone micro-nano bubbles is input into the ozone micro-nano bubble treatment equipment (4) through the outlet pipe C (33).

9. The device and method for treating marine aquaculture wastewater according to claim 8, characterized in that: The S5 specifically includes: S51: adjusting the air flow rate and ozone concentration of the ozone micro-nano bubble treatment device (4) according to the pollutant concentration; S52: The ozone micro-nano bubble treatment device (4) contains an array of ultraviolet lamp groups (43), and the number of lamp groups in operation is controlled according to the concentration of pollutants; S53: The ozone micro-nano bubble treatment device (4) is provided with an ozone recycling pipeline (41) on the upper part, which recovers the ozone tail gas from the bottom to the top and re-injects it into the air micro-nano bubble generating device (1), thereby realizing the recycling of ozone; S54: The water treated with ozone micro-nano bubbles enters the water collection device (44) through the water outlet pipe D (42); S55: drain the water in the water collection device through the drain pipe (45).

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