A device and method for concentrating microorganisms in ship ballast water

Abstract

The present invention provides a device and method for concentrating microorganisms in ship ballast water, and relates to the field of ships. The device includes a concentration tank and a low-voltage direct current power supply. The left and right side plates of the concentration tank are electrode plates, and the left and right electrode plates are symmetrically provided with microorganism aggregation grooves. The front and rear side plates of the concentration tank, as well as the upper cover plate and the bottom plate are all insulating plates; the concentration tank is provided with a water inlet and a drain; the bottom of the microorganism aggregation groove is provided with a sample outlet; the positive and negative poles of the low-voltage direct current power supply are respectively connected to the left and right electrode plates. The present invention utilizes the interfacial electrokinetic transmission phenomenon to concentrate the microorganisms in the ship ballast water, and is not affected by the cleanliness of the ship ballast water. The device can work for a long time without frequent cleaning and maintenance of the equipment, which saves time and labor, has low cost, and has a wide range of applications, and can realize convenient and efficient concentration of ship ballast water microorganisms.

Description

Technical Field

[0001] The present invention relates to the field of ships, and in particular to a device and method for concentrating microorganisms in ship ballast water. Background Art

[0002] Ballast water can keep a ship at a certain draft when empty so as not to capsize, thus ensuring the safe navigation of the ship. However, when ocean-going ships sail between oceans, if a large number of microorganisms contained in the ship's ballast water enter from one water area to another new water area lacking natural enemies, it will seriously affect the ecological balance of the local water area. Therefore, the rapid concentration and identification of microorganisms in ship ballast water is of great significance for preventing the invasion of foreign organisms and preventing ships from polluting the water environment.

[0003] The amount of ballast water loaded on ocean-going ships can reach 50% of the ship's cargo capacity. Therefore, the volume of ship ballast water is huge. Rapid concentration of microorganisms in ship ballast water can improve the detection and identification efficiency of microorganisms, which is the prerequisite for ship ballast water microbial detection. Most of the existing ship ballast water microbial concentration methods are achieved by introducing microfiltration membranes or nanofiltration membranes through filtration. Under normal circumstances, a 50μm filter can filter out plankton in ship ballast water, while a 20μm filter can filter out most of the phytoplankton in ballast water. Although this method is harmless to the environment, since the ship ballast water contains a large amount of flocs, it is easy to clog the filter screen and make it lose its filtering effect. Therefore, the filter screen must be repeatedly rinsed or replaced, which is time-consuming and laborious. As mentioned above, the existing ship ballast water microbial concentration technology still has certain limitations. Summary of the invention

[0004] The purpose of the present invention is to provide a ship ballast water microbial concentration device and method to solve the above problems in view of the deficiencies in the prior art.

[0005] On one hand, the present invention provides a ship ballast water microbial concentration device, which includes a concentration tank and a low-voltage direct current power supply. The left and right side walls of the concentration tank are electrode plates, and the front and rear side walls, the upper cover plate and the bottom plate of the concentration tank are insulating plates; microbial aggregation grooves are symmetrically arranged on the left and right side electrode plates; a water inlet and a drain outlet are arranged on the concentration tank; a sample outlet is arranged at the bottom of the microbial aggregation groove; and the positive and negative poles of the low-voltage direct current power supply are respectively connected to the left and right side electrode plates.

[0006] In the above technical solution, further, the number of the microorganism aggregation grooves on the electrode plate is at least one.

[0007] In the above technical solution, further, the microorganism aggregation groove is C-shaped and is an integrally formed structure with the electrode plate.

[0008] In the above technical solution, further, the water inlet is connected to a water inlet pipe, and a water inlet pump and a solenoid valve are provided on the water inlet pipe; the drain outlet is connected to a drain pipe via a drain valve; and the sample outlet is connected to a sample collection tube via a sample discharge valve.

[0009] In the above technical solution, further, the device also includes a water level detector, which is located on the side wall of the concentration tank and is electrically connected to the solenoid valve through a controller.

[0010] In the above technical solution, further, the insulating board is made of PVC.

[0011] Another aspect of the present invention provides a method for concentrating ship ballast water microorganisms using the above device, the method comprising the following steps:

[0012] S1. Water intake: First, inject the ship's ballast water into the concentration tank from the water inlet;

[0013] S2. Applying electric field: Turn on the low-voltage DC power supply and energize the electrode plate to generate a low-voltage DC electric field in the concentration tank. After the DC electric field runs for a period of time, the microorganisms in the ship's ballast water will gather in the microorganism aggregation groove on the electrode plate;

[0014] S3. Sampling: The ship's ballast water in the microbial aggregation tank is discharged through the sample discharge port by using the pressure difference to obtain a concentrated sample.

[0015] In the above technical solution, further, when taking in water, the ship's ballast water enters the concentration tank until the water level detector is submerged, and the water level detector transmits a signal to the solenoid valve, and the solenoid valve is closed to stop taking in water.

[0016] In the above technical solution, further, the voltage of the low-voltage DC power supply is 1-5V.

[0017] The working principle of the present invention is as follows: the air-water interface usually carries an electric charge, and the electric charge on the interface attracts ions of opposite signs in the water and repels ions of the same sign, eventually forming a double electric layer in the water area near the air-water interface. Under the action of an external DC electric field, the excess ions of opposite signs in the double electric layer move to one side of the electric field. The moving ions drive the water molecules to move through the viscosity effect, forming an electroosmotic flow. The movement of the electroosmotic flow will exert shear stress on the air-water interface, and the DC electric field will also exert an electric field force on the electric charge of the air-water interface, thereby causing the movement of the air-water interface. The moving interface drives the surrounding aqueous solution to move through the viscosity effect, forming an interfacial electrokinetic transmission phenomenon. In addition, the surface of microorganisms (such as microalgae) in the ship's ballast water also carries an electric charge, and under the action of an external DC electric field, the microorganism-water interface will also produce an electrokinetic transmission phenomenon.

[0018] When a low-voltage DC electric field is applied to water, the interfacial electrokinetic transport phenomenon generated by the above-mentioned horizontal air-water interface will cause the surrounding aqueous solution to flow, and the flowing aqueous solution will exert a hydrodynamic force on the microorganisms. At the same time, the electroosmotic flow generated on the surface of the microorganisms under the action of the low-voltage DC electric field will exert an additional hydrodynamic force on the microorganisms. Under the combined action of these two hydrodynamic forces, the microorganisms will move toward the electrode on one side of the DC electric field and eventually gather on one side of the electrode plate. The direction of movement of the microorganisms depends on the properties of the air-water interface and the charge they carry.

[0019] Since there are several C-shaped microorganism aggregation grooves on the electrode plate, the microorganisms in the ship's ballast water will gather in the concave part of the microorganism aggregation groove under the action of the DC electric field. After the low-voltage DC electric field acts for a period of time, the discharge valve is opened to discharge the water sample with a high microorganism content in the microorganism aggregation groove, and the concentrated ship ballast water sample is obtained.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention utilizes the interfacial electrokinetic transmission phenomenon to concentrate microorganisms in ship ballast water, which is not affected by the cleanliness of the ship ballast water. The device can work for a long time without frequent cleaning and maintenance of the equipment, which saves time and effort, has low cost, and has a wide range of applications. It can realize the convenient and efficient concentration of ship ballast water microorganisms;

[0022] 2. The present invention can perform aggregation and concentration treatment of ship ballast water microorganisms under the action of a low-voltage DC electric field, without the need for a high-voltage DC power supply, and with low power consumption;

[0023] 3. The low-voltage direct current used in the present invention will not kill the microorganisms in the ship's ballast water, and there is no need to add chemical reagents to the ship's ballast water, so it will not affect the subsequent detection of microbial activity in the concentrated sample of the ship's ballast water;

[0024] 4. The present invention uses low-voltage direct current to avoid chemical reactions caused by electrolyzing water, thereby preventing the generation of inflammable and explosive gases such as hydrogen, thereby improving safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic front view of the ship ballast water microorganism concentration device of the present invention;

[0026] Figure 2 It is a top view schematic diagram of the ship ballast water microorganism concentration device of the present invention;

[0027] Figure 3 It is a schematic diagram of the electrode plate structure of the present invention.

[0028] Among them, 1. water inlet; 2. water inlet pump; 3. solenoid valve; 4. electrode plate; 5. sample collection tube; 6. insulation plate; 7. drain valve; 8. drain outlet; 9. sample discharge valve; 10. sample outlet; 11. water level detector; 12. wire, 13. low voltage DC power supply. DETAILED DESCRIPTION

[0029] The following will be combined with the accompanying drawings of the present invention to clearly and completely describe the technical solutions 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 creative work are within the scope of protection of the present invention.

[0030] In the description of the present invention, it should be noted that the directions or positional relationships indicated by terms such as “upper”, “lower”, “front”, “back”, “inside”, “outside”, “left” and “right” are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience of describing the present invention and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations of the present invention.

[0031] like Figure 1-3 As shown, the present invention provides a device for concentrating microorganisms in ship ballast water, including a concentration tank and a low-voltage DC power supply 13, the left and right side walls of the concentration tank are electrode plates 4, and the electrode plates 4 are connected to the positive and negative electrodes of the low-voltage DC power supply 13 through wires 12; the front and rear side walls of the concentration tank and the upper cover and the bottom plate are PVC insulating plates 6; microorganism aggregation grooves are symmetrically arranged on the left and right side electrode plates, and the microorganism aggregation grooves are C-shaped and are an integrally formed structure with the electrode plates 4; a water inlet 1 and a drain outlet 8 are arranged on the concentration tank; the water inlet 1 is connected to the water inlet pipe, and the water inlet pipe is provided with a water inlet pump 2 and a solenoid valve 3; the drain outlet 8 is connected to the drain pipe through the drain valve 8; sample outlets 10 are arranged at the depressions of the microorganism aggregation grooves, and the sample outlets 10 are connected to the sample collection tube 5 through the sample discharge valve 9, and are used to collect concentrated ship ballast water microorganism samples; the water level detector 11 is located on the side wall of the concentration tank, and is electrically connected to the solenoid valve 3 through a controller, and is used to control the opening and closing of the solenoid valve 3.

[0032] The present invention also provides a method for concentrating microorganisms in ship ballast water, comprising the following steps:

[0033] S1, water intake: first, the ship's ballast water is injected into the concentration tank from the water inlet 1 through the water inlet pump 2 until the water level detector 11 is submerged, and the solenoid valve 3 is closed to stop the water intake;

[0034] S2, applying electric field: turning on the low voltage DC power supply 13 to energize the electrode plate 4, the electrode plate 4 generates a low voltage DC electric field in the concentration tank, when the DC electric field acts for a period of time, the microorganisms in the ship's ballast water will gather in the microorganism aggregation groove of the electrode plate 4; the voltage of the low voltage DC power supply is 1-5V;

[0035] S3, sampling: open the sample discharge valve 9, discharge the ship ballast water from the depression of the microorganism aggregation tank, and obtain a concentrated sample of the ship ballast water at the sample outlet 10.

[0036] The working principle of the present invention is:

[0037] Usually, the air-water interface carries an electric charge. The charge on the interface attracts ions of opposite sign in the water and repels ions of the same sign, eventually forming a double electric layer in the water area near the air-water interface. Under the action of an external DC electric field, the excess ions of opposite sign in the double electric layer move to one side of the electric field. The moving ions drive the movement of water molecules through the viscosity effect, forming an electroosmotic flow. The movement of the electroosmotic flow will exert shear stress on the air-water interface. At the same time, the DC electric field will also exert an electric field force on the charge of the air-water interface, thereby causing the movement of the air-water interface. The moving interface drives the movement of the surrounding liquid through the viscosity effect, forming an interfacial electrokinetic transmission phenomenon. Similarly, a double electric layer will also form on the surface of microorganisms in the ship's ballast water. Under the action of an external DC electric field, the surface of the microorganisms will also produce an interfacial electrokinetic transmission phenomenon.

[0038] When a low-voltage DC electric field is applied to water, the interfacial electrokinetic transmission phenomenon generated by the above-mentioned horizontal air-water interface will cause the surrounding aqueous solution to flow, and the flowing aqueous solution will exert a hydrodynamic force on the microorganisms. In addition, the electroosmotic flow generated on the surface of the microorganism under the action of the external DC electric field will also exert a hydrodynamic force on the microorganisms. Under the combined action of these two hydrodynamic forces, the microorganisms will move toward the electrode on one side of the DC electric field and gather on one side of the electrode plate 4, and the direction of their electrokinetic movement depends on the properties of the air-water interface and the charge carried by the microorganisms themselves.

[0039] like Figure 3 As shown, a C-shaped microorganism aggregation groove is provided on the electrode plate 4. Under the action of the low-voltage DC electric field, the microorganisms in the ship's ballast water will gather in the depression of the microorganism aggregation groove. After the low-voltage DC electric field acts for a period of time, the discharge valve 9 is opened to discharge the water sample with a higher microorganism content in the depression of the microorganism aggregation groove, and a concentrated ship ballast water sample is obtained. The number of microorganism aggregation grooves on the electrode plate 4 can be increased or decreased according to actual needs.

[0040] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and the inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A method for concentrating microorganisms in ship ballast water, characterized in that: The method uses a ship ballast water microbial concentration device, which includes a concentration tank and a low-voltage direct current power supply. The left and right side walls of the concentration tank are electrode plates, and the front and rear side walls, the upper cover plate and the bottom plate of the concentration tank are insulating plates; the left and right side electrode plates are symmetrically provided with microbial aggregation grooves; the concentration tank is provided with a water inlet and a drain outlet; the bottom of the microbial aggregation groove is provided with a sample outlet; the positive and negative poles of the low-voltage direct current power supply are respectively connected to the left and right side electrode plates; the microbial aggregation groove is C-shaped and is an integrally formed structure with the electrode plate; the voltage of the low-voltage direct current power supply is 1-5V; The method comprises the following steps: S1. Water intake: First, inject the ship's ballast water into the concentration tank from the water inlet; S2. Applying electric field: Turn on the low-voltage DC power supply and energize the electrode plate to generate a low-voltage DC electric field in the concentration tank. After the DC electric field runs for a period of time, the microorganisms in the ship's ballast water will gather in the microorganism aggregation groove on the electrode plate; S3. Sampling: Discharge the ship ballast water in the microorganism accumulation tank through the sample discharge port by using the pressure difference to obtain a concentrated sample; When taking in water, the ship's ballast water enters the concentration tank until the water level detector is submerged. The water level detector transmits a signal to the solenoid valve, which closes, stops the water intake, and creates an air-water interface.

2. The method for concentrating microorganisms in ship ballast water according to claim 1, characterized in that: The number of the microorganism aggregation grooves on the electrode plate is at least one.

3. The method for concentrating microorganisms in ship ballast water according to claim 1, characterized in that: The water inlet is connected to a water inlet pipe, on which a water inlet pump and a solenoid valve are arranged; the drain outlet is connected to a drain pipe via a drain valve; and the sample outlet is connected to a sample collection tube via a sample discharge valve.

4. The method for concentrating microorganisms in ship ballast water according to claim 1, characterized in that: The device also includes a water level detector, which is located on the side wall of the concentration tank and is electrically connected to the electromagnetic valve through a controller.

5. The method for concentrating microorganisms in ship ballast water according to claim 1, characterized in that: The insulating plate is made of PVC.

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