An integrated synergistic reaction device and method for aquaculture wastewater treatment

Abstract

This invention belongs to the field of wastewater treatment technology, specifically relating to an integrated synergistic reaction device for treating aquaculture wastewater. The device includes a plasma reactor, a microbubble generator, and a high-voltage power supply. The plasma reactor is a coaxial cylindrical dielectric barrier discharge reactor, comprising a dielectric layer cavity, an inner electrode within the cavity, an outer electrode on the outer wall of the cavity, an outlet at the upper end of the cavity, and an inlet at the lower end. A discharge gap is formed between the inner electrode and the cavity. The outlet of the microbubble generator is connected to the inlet of the plasma reactor, allowing the microbubble clusters generated by the generator to directly enter the discharge gap of the plasma reactor. The discharge gap has a width of 2 mm. Under a release pressure of 0.60 MPa, the microbubble generator produces a cluster of micro-nano bubbles with an average diameter of 20.9 μm and a concentration as high as 1.2 × 10^8 particles / mL.

Description

Technical Field

[0001] This invention belongs to the field of wastewater treatment technology, specifically relating to an integrated synergistic reaction device and method that deeply couples non-thermal plasma technology with microbubble / nanobubble technology, for the efficient degradation of organic pollutants, nutrients (ammonia nitrogen, phosphorus) and emerging trace pollutants such as antibiotics and hormones in aquaculture wastewater. Background Technology

[0002] In the treatment of aquaculture wastewater, the combination of plasma and micro / nano bubble technology is a promising emerging technology combination. Chinese patent CN108658209B discloses a "treatment system for hydroxyl radical mineralization of antibiotics in seawater aquaculture water," which mainly uses a plasma generator to excite a gaseous medium to form oxygen-active radical gas, and then uses a negative pressure jet device to generate micro / nano bubbles to treat the aquaculture water. Similar technologies include Chinese patents CN105905976B, CN121225705A, and CN120025021A. In these technologies, the plasma generator and microbubble generator are still connected in series as independent units. After generating plasma-active particle gas, it is then prepared into micro / nano bubbles. This process involves significant energy and material losses, resulting in the synergistic effect of the two technologies not being maximized.

[0003] The main reason why existing technologies cannot directly prepare plasma active particles in microbubbles is the bottleneck of reactor structure. Traditional dielectric barrier discharge (DBD) reactors often use a wide discharge gap (e.g., >5 mm), which makes it easy for bubbles to coalesce and generate large bubbles, resulting in a decrease in bubble concentration and uniformity. Ultimately, the free radicals generated are quenched due to long-distance migration before contacting pollutants, which limits the degradation rate.

[0004] The main limitations of existing reactors are: 1. Spatial integration: The generator and reactor are mostly separate units connected in series, resulting in long connecting pipelines and significant loss of plasma active particles; 2. Discharge gap: The gap is wide or not fixed, leading to uneven electric field distribution and low plasma active particle capture rate; 3. Cavitation method: Primarily low-pressure dissolved gas or general cavitation, resulting in large bubble size and low concentration (1:10 gas-to-water ratio), making it impossible to form a uniform reaction interface in the discharge zone. Therefore, the key to the application of this technology lies in achieving a uniform distribution of extremely high-density microbubbles in an extremely narrow space while maintaining stable discharge, and making each microbubble an independent "microreactor" to shorten the transport path of plasma active particles from the gas phase to the liquid phase. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method to solve this problem by in-situ coupling of narrow gap physical confinement and high-pressure cavitation. This invention designs an integrated synergistic reaction device for aquaculture wastewater treatment that is compact in structure, has high energy and mass transfer efficiency, and can achieve in-situ deep synergy between plasma and microbubbles.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: An integrated synergistic reaction device for treating aquaculture wastewater includes a plasma reactor, a microbubble generator, and a high-voltage power supply, all housed within the same container. The plasma reactor is a coaxial cylindrical dielectric barrier discharge reactor, comprising a dielectric layer cavity, an inner electrode within the cavity, an outer electrode on the outer wall of the cavity, an outlet at the upper end of the cavity, and an inlet at the lower end. A discharge gap is formed between the inner electrode and the cavity. The outlet of the microbubble generator is connected to the inlet of the plasma reactor, allowing the microbubble clusters generated by the generator to directly enter the discharge gap of the plasma reactor. The discharge gap has a width of 2 mm. Under a release pressure of 0.60 MPa, the microbubble generator produces a cluster of micro- and nanobubbles with an average diameter of 20.9 μm and a concentration as high as 1.2 × 10^8 particles / mL.

[0007] Furthermore, the medium layer cavity is a hollow quartz tube.

[0008] Furthermore, the outlet of the microbubble generator is located at the bottom side of the cavity of the plasma reactor. The aquaculture wastewater to be treated is pumped into the cavity of the plasma reactor from the bottom side and passes vertically through the plasma discharge gap.

[0009] Furthermore, the high-voltage power supply is connected to the inner and outer electrodes of the plasma reactor, and the voltage of the high-voltage power supply is 80V.

[0010] Furthermore, the aquaculture wastewater to be treated is pumped into the microbubble generator at a flow rate of 480 mL / min, and air is drawn into the microbubble generator at a flow rate of 10 mL / min.

[0011] Furthermore, there are 1 to 5 plasma reactors, and multiple plasma reactors are connected in parallel.

[0012] Another object of the present invention is to provide an integrated synergistic reaction method for treating aquaculture wastewater, using the aforementioned integrated synergistic reaction device for treating aquaculture wastewater, comprising the following steps: Step 1: Start the microbubble generator and pump the aquaculture wastewater to be treated into the system at a flow rate of 480 mL / min. At the same time, air is drawn into the microbubble generator 2 at a flow rate of 10 mL / min to generate a microbubble cluster, which is then pumped into the cavity of the plasma reactor from the side inlet at the bottom of the plasma reactor. Step 2: Turn on the high-voltage power supply and gradually increase the voltage to 80V to generate stable non-thermal plasma in the plasma discharge region of the dielectric layer cavity; Step 3: At the moment of discharge, plasma active particles are instantly generated and bound inside and at the interface of microbubbles. By utilizing the Brownian motion and extremely short diffusion distance of microbubbles, in-situ capture and mass transfer of plasma active particles are achieved. Step 4: The aquaculture wastewater to be treated passes vertically through the plasma discharge zone to carry out a synergistic oxidation reaction. Combined with the local high temperature and high pressure generated during the collapse of microbubbles, the pollutants are oxidized in situ. Step 5: Collect the treated water sample from the outlet and test its removal rates of COD, ammonia nitrogen, total phosphorus, and specific antibiotics / hormones.

[0013] The present invention provides an integrated synergistic reaction device and method for treating aquaculture wastewater, the advantages of which are: I. The wide gap in traditional dielectric barrier discharge reactors leads to bubble coalescence in the discharge region. This invention, through a narrow 2 mm gap combined with a high release pressure of 0.60 MPa, ensures that microbubbles with a diameter of 20.9 μm are uniformly distributed in the discharge region at an extremely high concentration (1.2 × 10^8 particles / mL). This specific physical size constraint makes each microbubble an independent "microreactor," greatly improving the capture efficiency of plasma active particles.

[0014] II. Experimental data demonstrate that using this integrated synergistic reaction device for aquaculture water treatment increases the removal efficiency of COD, 17α-methyltestosterone, and tetracycline in the water to 2.6 times, 2.0 times, and 1.4 times that of the plasma-only group, respectively, while significantly reducing unit energy consumption. The energy consumption for COD treatment is only 38.9% of that of the existing plasma-only technology. This significant progress fully proves that the "narrow-gap microreactor" design is not a simple combination of elements, but rather produces an unexpected breakthrough in synergistic energy efficiency. Specifically, the device achieves a removal rate of 80-83% for ammonia nitrogen, 61-77% for total phosphorus, approximately 76% for tetracycline, and approximately 48% for 17α-methyltestosterone. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of an integrated synergistic reaction device for treating aquaculture wastewater according to the present invention; Figure 2This is a schematic diagram of the plasma reactor structure of the present invention. Detailed Implementation

[0016] The present invention will be described in detail below with reference to specific implementation examples. These examples will help those skilled in the art to further understand the present invention, but do not limit the present invention in any way.

[0017] like Figure 1 , Figure 2 As shown, this invention relates to an integrated synergistic reaction device for treating aquaculture wastewater, comprising a plasma reactor 1, a microbubble generator 2, and a high-voltage power supply 3, all housed in the same container 01. The plasma reactor 1 is a coaxial cylindrical dielectric barrier discharge reactor, including a dielectric layer cavity 12. An inner electrode 11 is disposed within the dielectric layer cavity 12, and an outer electrode 14 is disposed on the outer wall of the dielectric layer cavity 12. An outlet 16 is disposed at the upper end of the dielectric layer cavity 12, and an inlet 15 is disposed at the lower end of the dielectric layer cavity 12. A discharge gap 13 is formed between the inner electrode 11 and the dielectric layer cavity 12. The outlet of the microbubble generator 2 is connected to the inlet 15 of the plasma reactor 1, allowing the microbubble cluster generated by the microbubble generator 2 to directly enter the discharge gap 13 of the plasma reactor 1. The width of the discharge gap 13 is 2 mm. Under a release pressure of 0.60 MPa, the microbubble generator 2 generates a cluster of micro-nano bubbles with an average diameter of 20.9 μm and a concentration as high as 1.2 × 10^8 particles / mL.

[0018] This scheme integrates the plasma reactor 1 and the microbubble generator 2 into the same device 01. The release point of the microbubbles is directly located inside or adjacent to the plasma discharge region, ensuring that the microbubbles are rapidly enveloped by plasma after generation. The plasma discharge generates a high concentration of active particles inside the microbubbles and at the gas-liquid interface. These active particles are bound inside the microbubbles or attached to their surfaces and are transported to various parts of the reaction device with the movement of the microbubbles, greatly expanding the active area. Furthermore, during the rise or movement with the water flow, the collapse of the microbubbles generates local high temperature, high pressure, and shock waves, further exciting the generation of more free radicals, which then undergo a chain reaction with the active substances generated by the plasma, forming a multi-stage oxidation pathway of "plasma activation - bubble transport - collapse enhancement". The degradation efficiency of pollutants is significantly higher than that of simply superimposing two technologies, truly solving the "mass transfer bottleneck" problem of active substances in traditional plasma treatment. At the same time, the integrated design reduces pipeline connections and space occupation, making the system more stable and easier to automate.

[0019] Meanwhile, the discharge gap of the coaxial cylindrical dielectric barrier discharge reactor is precisely set to 2 mm. This narrow gap design, combined with microbubbles with specific parameters, forces the bubbles to fill the discharge area, avoiding bubble aggregation and ensuring the uniformity and efficiency of the discharge. Furthermore, a high-density micro-nano bubble cluster with an average diameter of 20.9 μm and a concentration as high as 1.2 × 10^8 particles / mL is generated by a hydraulic cavitation device (an existing technology, commercially available) at a specific release pressure of 0.60 MPa. These microbubbles with specific parameters can be uniformly distributed within the narrow 2 mm discharge gap, with each microbubble becoming an independent "microreactor".

[0020] Furthermore, the dielectric layer cavity 12 is a hollow quartz tube. Quartz material is resistant to high temperatures and electrically insulating, making it a good material choice for the dielectric layer cavity of a plasma reactor.

[0021] Furthermore, the outlet of the microbubble generator 2 is located at the bottom side of the cavity of the plasma reactor 1. The aquaculture wastewater to be treated is pumped into the cavity of the plasma reactor 1 from the bottom side and passes vertically through the plasma discharge gap 13, so that the microbubble group generated by the microbubble generator 2 directly enters the discharge gap 13 of the plasma reactor 1.

[0022] Furthermore, the high-voltage power supply 3 is connected to the inner electrode 11 and the outer electrode 14 of the plasma reactor 1. The voltage of the high-voltage power supply 3 is 80V. The 80V voltage can generate an extremely high electric field strength in the 2mm discharge gap, while limiting the blind merging of bubbles during the flow process.

[0023] Furthermore, the aquaculture wastewater to be treated is pumped into the microbubble generator 2 at a flow rate of 480 mL / min, and air is drawn into the microbubble generator 2 at a flow rate of 10 mL / min. The flow rate of the wastewater and the flow rate of the air can generate a stable microbubble cluster.

[0024] Furthermore, there are 1 to 5 plasma reactors 1, with multiple plasma reactors 1 connected in parallel. A single plasma reactor can operate in a circulating water treatment mode, or multiple plasma reactors 1 can be connected in parallel, resulting in high operating efficiency.

[0025] The present invention provides an integrated synergistic reaction method for treating aquaculture wastewater, using the aforementioned integrated synergistic reaction device for treating aquaculture wastewater, comprising the following steps: Step 1: Start the microbubble generator 2 and pump the aquaculture wastewater to be treated into the system at a flow rate of 480 mL / min. At the same time, air is drawn into the microbubble generator 2 at a flow rate of 10 mL / min to generate a microbubble cluster. The wastewater rich in high concentration of micro-nano bubbles (average diameter 20.9 μm, concentration 1.2×10^8 particles / mL) is pumped into the cavity of the plasma reactor 1 through the bottom side inlet 15.

[0026] Step 2: Turn on the high-voltage power supply 3 and gradually increase the voltage to 80V. Stable non-thermal plasma is generated in the plasma discharge region (i.e., discharge gap 13) of the dielectric layer cavity 12. Due to the geometric limitation of the 2 mm narrow discharge gap, microbubbles are forced to uniformly fill the entire discharge region, forming countless gas-liquid contact "micro-interfaces".

[0027] Step 3: At the moment of discharge, plasma active particles are instantly generated and bound inside and at the interface of the microbubble. By utilizing the Brownian motion of the microbubble and the extremely short diffusion distance (μm level), in-situ capture and efficient mass transfer of plasma active particles are achieved.

[0028] Step 4: Wastewater rich in microbubbles passes vertically through the plasma discharge zone, undergoing a synergistic oxidation reaction. Combined with the localized high temperature and pressure (secondary effect) generated during microbubble collapse, pollutants such as organic matter, ammonia nitrogen, total phosphorus, tetracycline, and 17α-methyltestosterone are oxidized in situ. The hydraulic retention time can be set according to the water quality of the aquaculture wastewater to be treated.

[0029] Step 5: The treated water sample is collected from outlet 16 and its removal rates of COD, ammonia nitrogen, total phosphorus, and specific antibiotics / hormones can be detected. Experiments show that the device can remove 80-83% of ammonia nitrogen, 61-77% of total phosphorus, about 76% of tetracycline, and about 48% of 17α-methyltestosterone.

[0030] The above steps can be carried out in a circulating water treatment mode or in the form of multiple plasma reactors 1 connected in parallel, depending on the amount and quality of the aquaculture wastewater to be treated.

[0031] The above specific embodiments are used to explain and illustrate the present invention, but not to limit the present invention. Any modifications and changes made to the present invention within the spirit and scope of the claims shall fall within the protection scope of the present invention.

Claims

1. An integrated synergistic reaction device for treating aquaculture wastewater, characterized in that... The reactor includes a plasma reactor (1), a microbubble generator (2), and a high-voltage power supply (3) all housed in the same container (01). The plasma reactor (1) is a coaxial cylindrical dielectric barrier discharge reactor, comprising a dielectric layer cavity (12), an inner electrode (11) disposed within the dielectric layer cavity (12), an outer electrode (14) disposed on the outer wall of the dielectric layer cavity (12), an outlet (16) disposed at the upper end of the dielectric layer cavity (12), and an inlet (15) disposed at the lower end of the dielectric layer cavity (12). A discharge gap (13) is formed between the microbubble generator (2) and the dielectric layer cavity (12). The outlet of the microbubble generator (2) is connected to the inlet (15) of the plasma reactor (1), so that the microbubble group generated by the microbubble generator (2) directly enters the discharge gap (13) of the plasma reactor (1). The width of the discharge gap (13) is 2 mm. The microbubble generator (2) generates a micro-nano bubble group with an average diameter of 20.9 μm and a concentration as high as 1.2 × 10^8 particles / mL under a release pressure of 0.60 MPa.

2. The integrated synergistic reaction device for treating aquaculture wastewater as described in claim 1, characterized in that... The medium layer cavity (12) is a hollow quartz tube.

3. The integrated synergistic reaction device for treating aquaculture wastewater as described in claim 1, characterized in that... The outlet of the microbubble generator (2) is located at the bottom side of the cavity of the plasma reactor (1). The aquaculture wastewater to be treated is pumped into the cavity of the plasma reactor (1) from the bottom side and passes vertically through the plasma discharge gap (13).

4. The integrated synergistic reaction device for treating aquaculture wastewater as described in claim 1, characterized in that... The high-voltage power supply (3) is connected to the inner electrode (11) and outer electrode (14) of the plasma reactor (1), and the voltage of the high-voltage power supply (3) is 80V.

5. The integrated synergistic reaction device for treating aquaculture wastewater as described in claim 1, characterized in that... The aquaculture wastewater to be treated is pumped into the microbubble generator (2) at a flow rate of 480 mL / min, and air is drawn into the microbubble generator (2) at a flow rate of 10 mL / min.

6. The integrated synergistic reaction device for treating aquaculture wastewater as described in claim 1, characterized in that... There are 1 to 5 plasma reactors (1), and multiple plasma reactors (1) are connected in parallel.

7. An integrated synergistic reaction method for treating aquaculture wastewater, using the integrated synergistic reaction device for treating aquaculture wastewater as described in any one of claims 1-6, characterized in that... Includes the following steps: Step 1: Start the microbubble generator (2) and pump the aquaculture wastewater to be treated into the system at a flow rate of 480 mL / min. At the same time, air is drawn into the microbubble generator 2 at a flow rate of 10 mL / min to generate a microbubble cluster, which is then pumped into the cavity of the plasma reactor (1) from the side inlet (15) at the bottom of the plasma reactor (1). Step 2: Turn on the high voltage power supply 3 and gradually increase the voltage to 80V to generate stable non-thermal plasma in the plasma discharge region of the dielectric layer cavity (12); Step 3: At the moment of discharge, plasma active particles are instantly generated and bound inside and at the interface of microbubbles. By utilizing the Brownian motion and extremely short diffusion distance of microbubbles, in-situ capture and mass transfer of plasma active particles are achieved. Step 4: The aquaculture wastewater to be treated passes vertically through the plasma discharge zone to carry out a synergistic oxidation reaction. Combined with the local high temperature and high pressure generated during the collapse of microbubbles, the pollutants are oxidized in situ. Step 5: The treated water sample is collected from the outlet (16) and its COD, ammonia nitrogen, total phosphorus, and removal rate of specific antibiotics / hormones can be detected.

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