A biological sediment cultivation device and method simulating tidal action

Abstract

This invention discloses a biological sediment cultivation device simulating tidal action, comprising a base plate, a cultivation tank on top of the base plate, and a biological sediment cultivation tank within the cultivation tank; an angle adjustment device and an adjustment shaft are provided on the base plate; the cultivation tank is rotatably connected to the base plate via the adjustment shaft, and rotates by the adjustment shaft; an inlet pipe is connected to the cultivation tank, and a water pump is installed on the inlet pipe; a water level sensor is fixed on the biological sediment cultivation tank; a timer switch is connected to the water pump; an electromagnetic valve is installed on the inlet pipe; an outlet pipe is connected to the cultivation tank, and an electromagnetic valve is installed on the outlet pipe; a timer switch is connected to the electromagnetic valve; a lamp is located above the cultivation tank, and a support unit is provided on the cultivation tank; the lamp is connected to a timer switch. It also includes a method for simulating tidal action to cultivate biological sediment. This device and method can simulate a tidal environment and cultivate biological sediment identical to that found in nature.

Description

Technical Field

[0001] This invention belongs to the field of coastal microbial sediment cultivation devices, specifically relating to a biological sediment cultivation device and method under simulated tidal action. Background Technology

[0002] Tidal flats are important geomorphic units of the coastal zone and a hot topic in the study of land-sea interactions, possessing significant ecological, economic, and engineering importance. Sediment is a fundamental hydrological element of tidal flats, and its movement and transport processes influence the evolution of the tidal flat system. In recent years, with a deeper understanding of the properties of tidal flat sediment and the development of interdisciplinary studies, the impact of microbial activity on the movement and transport of tidal flat sediment has received increasing attention. Studies have shown that benthic microalgae and bacteria in tidal flats can secrete large amounts of EPS (composed of capsules, mucus layers, and other surface substances) and other organic matter, which combine with sediment particles to form "biosediment." This not only significantly increases the initiation shear stress of sediment and reduces its erosion potential but also affects the lateral transport and sedimentation characteristics, thereby altering the geomorphic evolution of tidal flats. Therefore, it is urgent to strengthen our understanding of biosediment in tidal flats.

[0003] Indoor controlled experiments are one of the important methods for studying biological sediments. Unlike traditional physicochemical sediment studies, the study of the movement and transport characteristics of biological sediments requires that "clean sand," that is, sediment without microorganisms, be placed in a culture device and cultured for a certain period of time using a culture medium rich in microorganisms, so that the microorganisms can fully integrate with the sediment.

[0004] Current research on the cultivation of biological sediments often relies on prolonged immersion in a culture medium due to a lack of suitable cultivation equipment. However, under real-world conditions, tidal flat sediments are intermittently submerged and exposed to air due to tidal forces. Therefore, biological sediments cultivated without considering this crucial intermittent submersion or exposure caused by tides will inevitably differ significantly in structure and properties from natural tidal flat biological sediments. Subsequent sediment erosion experiments will also fail to reveal the actual movement patterns of tidal flat sediments. Therefore, there is an urgent need for an experimental apparatus and cultivation method that can simulate the effects of tidal forces indoors to advance indoor experimental research on tidal flat biological sediments. Summary of the Invention

[0005] To overcome the shortcomings of existing technologies, this invention proposes a biological sediment cultivation device and method under simulated tidal action, mainly to solve the technical problem of how to simulate the tidal environment and make the cultivated biological sediment as similar as possible to the biological sediment of natural tidal flats.

[0006] To achieve the above objectives, the present invention provides a biological sediment cultivation device simulating tidal action, comprising a base plate, a cultivation tank above the base plate, and a biological sediment cultivation trough within the cultivation tank; a first sand box and a second sand box for loading clean sand are placed in the biological sediment cultivation trough; the base plate is provided with an angle adjustment device and an adjustment shaft for adjusting the tilt angle of the cultivation tank, the angle adjustment device and the adjustment shaft being located at opposite ends of the cultivation tank; the cultivation tank is rotatably connected to the base plate via the adjustment shaft, and rotates under the drive of the angle adjustment device; a water inlet pipe is connected to the cultivation tank, one end of which communicates with the biological sediment cultivation trough, and the other end... A nutrient solution tank is connected to the inlet pipe, and a water pump is installed on the inlet pipe to drive the nutrient solution into the biological sediment culture tank. A water level sensor is fixed on the inner wall of the biological sediment culture tank. The water pump is connected to a timer switch. A solenoid valve is installed on the inlet pipe. The water level sensor is electrically connected to the water pump, timer switch, and solenoid valve. An outlet pipe is connected to the culture tank. One end of the outlet pipe is connected to the biological sediment culture tank, and the other end is connected to a waste liquid tank. A solenoid valve is installed on the outlet pipe. A timer switch is connected to the solenoid valve. A lamp is installed above the culture tank. A support unit is installed on the culture tank to raise the height of the lamp. The lamp is connected to a timer switch.

[0007] Furthermore, the biological sediment culture tank is divided into a culture zone and a water inlet buffer zone, with the first sandbox and the second sandbox placed in the culture zone; the water inlet pipe and the water outlet pipe are connected to the water inlet buffer zone; an upper energy dissipation plate is fixed on the inner wall of the water inlet buffer zone, and the lower end of the upper energy dissipation plate does not contact the lower end of the water inlet buffer zone.

[0008] The water flow entering the cultivation area is buffered by the upper energy dissipation plate to prevent the water flow from impacting the clean sand and causing the clean sand to be washed away.

[0009] Furthermore, the lower surface wall of the water inlet buffer zone is lower than the lower surface wall of the culture zone, and the intersection of the lower surface wall of the water inlet buffer zone and the lower surface wall of the culture zone is set as a slope, which is denoted as the lower energy dissipation slope.

[0010] The lower energy dissipation slope is used to further reduce the impact of water flow on clean sand and further prevent the clean sand from being washed away.

[0011] Furthermore, a first support and a second support for fixing the first sandbox and the second sandbox are fixed on the lower surface wall of the cultivation area;

[0012] Viewed from above, the first support is L-shaped; the upper surface of the first support is cut downward to form an L-shaped first locking part, and the two ends of the first locking part extend to the two ends of the first support; the inner side of the first locking part extends to the inner side of the first support; the outer edge of the corner of the first sandbox or the second sandbox is in contact with the side wall of the first locking part.

[0013] Viewed from above, the second support is shaped like a cross and consists of four first supports; the outer edges of the four first supports are in contact with each other and are fixedly connected.

[0014] The first and second supports are used to limit the movement of the first and second sandboxes, preventing them from moving under the impact of the water flow.

[0015] Furthermore, an oxygenation pump for providing oxygen to microorganisms is fixed on the inner wall of the culture zone.

[0016] An oxygen pump is used to supply oxygen to microorganisms, preventing them from dying due to lack of oxygen.

[0017] It also includes a method for cultivating biological sediment under simulated tidal action, comprising the following steps: S1: going to the tidal flat site for observation; surveying and recording the slope of the tidal flat, the alternation period between the submerged and exposed periods during a tidal process, the time of day-night alternation, and the average daily light intensity of the tidal flat; and collecting several sediment samples and seawater samples from the surface of the tidal flat site that are rich in algae and bacteria.

[0018] S2: Based on the data obtained in S1, adjust the tilt angle of the biological sediment culture tank using an angle adjustment device to make it close to the slope of the tidal flat; adjust the height of the lamp tube using a support unit to make the light intensity received by the biological sediment culture tank close to the daily average light intensity recorded in the observation; analyze the salinity, total nitrogen, and total phosphorus content of the seawater sample in the laboratory, and prepare a nutrient solution with the same salinity, total nitrogen, and total phosphorus content characteristics as seawater.

[0019] S3: Take 50.0g of mud and sand sample and put it into a container. Add 200ml of deionized water and stir for 15min. Centrifuge at 3000g for 15min to separate large particles of impurities from the liquid. The liquid after separation from large particles of impurities is the supernatant.

[0020] Take the supernatant, filter out a small amount of unseparated impurities to obtain the leachate of the mud and sand sample; pour the leachate into a 500ml glass container, add the nutrient solution prepared in step S2 to 500ml, aerate the nutrient solution using an oxygen pump, and incubate under a lamp for 3-5 days; during this period, change the liquid in the glass container 1-2 times to obtain the microbial enrichment solution; in S3, the method of changing the liquid in the glass container is: pour out half of the liquid in the glass container, and then add an equal amount of nutrient solution to the glass container;

[0021] S4: Place an equal number of first and second sand boxes in the cultivation area. Spread clean sand in each first and second sand box, and add water to each first and second sand box until the clean sand is just submerged. After the clean sand in the first and second sand boxes is completely wetted, smooth the surface of the clean sand.

[0022] S5: Close solenoid valve 2 and turn on the water pump to input nutrient solution into the biological sediment culture tank. After the total liquid level of nutrient solution and water reaches the height of the water level sensor, turn off the water pump. At this time, the total liquid level of nutrient solution and water is higher than the surface of the clean sand. Pour the microbial enrichment solution prepared in step S3 into the biological sediment culture tank and stir with a glass rod to make the microbial enrichment solution evenly diffuse into the total liquid level of nutrient solution and water in S5. Turn on the lamp and oxygen pump. The lamp illuminates the liquid in the biological sediment culture tank at this time, and the oxygen pump oxygenates the liquid. Let it stand for 1-2 days to allow the microorganisms to adapt to the laboratory culture conditions and be able to attach and grow on the surface of the clean sand in each sand box. Change the liquid in the biological sediment culture tank once during the standing period. The way to change the liquid in the biological sediment culture tank in S5 is to pour out half of the liquid in the biological sediment culture tank and then add an equal amount of nutrient solution.

[0023] S6: After the settling phase in S5 is completed, open solenoid valve two; after all the liquid in the biological sediment culture tank is discharged into the waste liquid tank by gravity, solenoid valve two is closed; the biological sediment culture tank simulates the exposed beach period and lasts for a period of time, the length of which is the same as the natural exposed beach period; after the simulated exposed beach period ends, open solenoid valve one, turn on the water pump and close solenoid valve two, the water pump inputs nutrient solution into the biological sediment culture tank to the height of the water level sensor and then closes, simulating the submersion period and lasting for a period of time, the length of which is the same as the natural submersion period; after the simulated submersion ends, open solenoid valve two; the lamp opening and closing time is the same as the day-night cycle time, and the lamp opening and closing pattern is the same as the natural day-night cycle pattern. Beneficial effects

[0024] By using a cultivation device to simulate the natural flooding and exposure periods, the cultured biological sediment is almost identical to that in nature. Attached Figure Description

[0025] Figure 1 This is a schematic diagram of the overall structure of the device;

[0026] Figure 2 yes Figure 1 Top view;

[0027] Figure 3 This is a schematic diagram of the first support structure;

[0028] Figure 4 This is a schematic diagram of the second support structure.

[0029] 1. Base plate; 2. Angle adjustment device; 3. Adjustment shaft; 4. Culture tank; 5. Water inlet buffer zone; 6. Culture area; 7. Upper energy dissipation plate; 8. Lower energy dissipation slope; 9. Water inlet pipe; 10. Nutrient solution tank; 11. Water level sensor; 12. Water pump; 14. Timer switch one; 15. Drain pipe; 16. Waste liquid tank; 17. Solenoid valve two; 18. Timer switch two; 19. Support unit; 20. Lamp tube; 21. Timer switch three; 22. First sandbox; 23. Second sandbox; 24. Oxygen pump; 25. Solenoid valve one; 26. First support; 27. Second support; 28. First clamping part. Implementation

[0030] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] See Figure 1 A biological sediment cultivation device simulating tidal action includes a base plate 1, with an angle adjustment device 2 and an adjustment shaft 3 respectively installed on the upper surface of the base plate 1. Figure 1 As shown, the angle adjustment device 2 and the adjustment shaft 3 are located at the left and right ends of the base plate 1, respectively. The length direction of the angle adjustment device 2 is along the vertical direction, and the axis of the adjustment shaft 3 is perpendicular to the paper. In this embodiment, the angle adjustment device 2 is a cylinder; in other embodiments, it can also be an electric push rod or other devices, with the axis of the cylinder piston rod along the vertical direction.

[0032] A culture tank 4 is located above the cylinder, and the culture tank 4 contains a biological sediment culture tank. The cylinder body is hinged to the base plate 1 via shaft one, and the piston rod of the cylinder is hinged to the lower wall of the culture tank 4 via shaft two. The axes of shaft one and shaft two are both perpendicular to the ground plane. Figure 1 Paper surface. The lower surface of the culture tank 4 is hinged to the base plate 1 via the adjusting shaft 3.

[0033] The angle adjustment device 2 is electrically connected to a computer, which controls the extension and retraction of the cylinder. This allows the biological sediment culture tank to tilt about the axis of the adjustment shaft 3, with the angle between the lower surface of the outer wall of the biological sediment culture tank and the upper surface of the base plate 1 ranging from 0 to 5°.

[0034] The right end of the biological sediment cultivation tank is the inlet buffer zone 5, and the left end is the cultivation zone 6. An upper energy dissipation plate 7 is fixed to the inner wall of the inlet buffer zone 5. Figure 1 Looking from the center, the upper energy dissipation plate 7 is perpendicular to... Figure 1Both ends of the upper energy dissipation plate 7 are fixed to the inner wall of the water inlet buffer zone 5. The lower end of the upper energy dissipation plate 7 does not contact the lower surface wall of the biological sediment culture tank.

[0035] like Figure 1 As shown, the lower surface of the inlet buffer zone 5 is recessed downwards, meaning it is lower than the lower surface of the culture zone 6. The junction of the inlet buffer zone 5 and the culture zone 6 is sloped, denoted as the lower energy dissipation slope 8, with the left end higher than the right end. The nutrient solution flows from the inlet buffer zone 5 through the culture zone 6. The upper energy dissipation plate 7 and the lower energy dissipation slope 8 reduce the inlet velocity of the culture zone 6 by reducing the kinetic energy of the water flow during inlet, thus preventing disturbance to the surface of the sediment in the culture zone 6.

[0036] The culture tank 4 is connected to a water inlet / outlet system, which is located at the water inlet buffer zone 5.

[0037] Specifically, the water inlet and outlet system includes an inlet pipe 9, which is fixedly connected to the outer wall of the culture tank 4 and communicates with the water inlet buffer zone 5 of the biological sediment culture tank. The end of the inlet pipe 9 furthest from the culture tank 4 is connected to a nutrient solution tank 10. A water pump 12 is connected to the inlet pipe 9 to pump the nutrient solution into the water inlet buffer zone 5. A water level sensor 11 is installed on the inner wall of the culture tank 4, and the water pump 12 is electrically connected to a timer switch 14. When the nutrient solution needs to submerge the "clean sand," the water pump 12 is turned on via the timer switch 14. When the liquid level in the biological sediment culture tank reaches the height of the water level sensor 11, the water pump 12 is turned off. An electromagnetic valve 25 is installed on the inlet pipe 9 to open the inlet pipe 9 when the water pump 12 starts and to close the inlet pipe 9 when the water pump 12 stops. The timer switch 14, water pump 12, water level sensor 11, and electromagnetic valve 25 are all electrically connected.

[0038] A drain pipe 15 is fixed to the outer wall of the culture tank 4, and the drain pipe 15 is connected to the water inlet buffer zone 5 of the biological sand culture tank. The end of the water inlet pipe 9 away from the culture tank 4 is connected to the waste liquid tank 16. A solenoid valve 17 is connected to the drain pipe 15. Nutrient solution is pumped into the biological sand culture tank by the water pump 12, and the solenoid valve 17 is closed while the nutrient solution submerges the "clean sand" placed in the biological sand culture tank. When the soil is exposed (when the nutrient solution is discharged), the solenoid valve 17 is opened. Due to the angle adjustment device 2, the biological sand culture tank is tilted towards the drain pipe 15, and the nutrient solution flows naturally into the waste liquid tank 16 through the drain pipe 15. The solenoid valve 17 is electrically connected to the timer switch 18 and is controlled by the timer switch 18 to open and close.

[0039] Two support units 19 are fixed on the culture tank 4, such as Figure 1As shown, the length direction of the support unit 19 is vertical. A lamp plate is positioned above the two support units 19, with its length direction being horizontal. A lamp tube 20 is mounted on the lamp plate, positioned above the culture tank 4. The lamp tube 20 emits light to provide illumination for the microorganisms in the culture area 6 of the biological sediment culture tank. The lamp tube 20 is electrically connected to a timer switch 21 to control the on / off duration of the lamp tube 20, simulating day and night. In this embodiment, the support unit 19 is an electric actuator; in other embodiments, it can be a cylinder or other device. The support unit 19 is fixedly connected to the lamp plate and is used to change the height of the lamp tube 20 by extending or retracting, thereby changing the light intensity of the lamp tube 20.

[0040] See Figure 2 The lower surface of the culture area 6 of the biological sediment culture tank is equipped with 8 first sand boxes 22. For example... Figure 2 As shown, the first sandbox 22 is arranged in two columns in the left-right direction, each column along... Figure 2 There are 4 first sandboxes in total, located in the top and bottom directions; that is, with Figure 2 Looking from the left and right, the first sandbox 22 has 4 rows arranged in the vertical direction.

[0041] The lower wall of the cultivation zone 6 of the biological sediment culture tank is equipped with 8 second sand boxes 23. For example... Figure 1 As shown, the aforementioned water level sensor 11 is located above the first sandbox 22 and the second sandbox 23. Figure 2 As shown, the second sandbox 23 is arranged in 4 columns in the left and right directions, and each column has 2 second sandboxes 23 in the vertical direction, that is, in order to Figure 2 Looking at the top and bottom, the second sandbox 23 has two rows arranged in the top and bottom direction. For example... Figure 2 As shown, the second sandbox 23 is located to the right of the first sandbox 22.

[0042] Both the first sandbox 22 and the second sandbox 23 are rectangular boxes with right angles at their outer edges. Therefore, 36 first supports 26 and 7 second supports 27 are designed to limit the movement of the first sandbox 22 and the second sandbox 23.

[0043] Among them, such as Figure 3 As shown, the first support 26 is L-shaped. Figure 3 Viewed vertically, the upper surface of the first support 26 is cut downwards to form an "L"-shaped first locking portion 28. Both ends of the first locking portion 28 extend to both ends of the first support 26. The inner side of the first locking portion 28 extends to the inner side of the first support 26. The first support 26 is fixed to the lower surface of the biological sediment culture tank by bolts or other means. When placing the first sandbox 22 and the second sandbox 23, the outer edge of the corner of the first sandbox 22 or the second sandbox 23 fits against the side wall of the first locking portion 28, and the first sandbox 22 and the second sandbox 23 are limited by the side wall of the first locking portion 28.

[0044] Similarly, such as Figure 4 As shown, the second support 27 is in the shape of a cross. The second support 27 is composed of four first supports 26, whose outer edges are in contact with each other. The four first supports 26 are fixed together by welding or other means to form the second support 27. Naturally, the upper surface of the second support 27 has four second locking portions, which are identical to the first locking portions 28. The second support 27 is fixed to the lower surface wall of the biological sediment culture tank by bolts or other means. The outer edges of the corners of the four adjacent first sand boxes 22 and second sand boxes 23 are fitted with the side walls of the second locking portions, which simultaneously limit the positioning of the four adjacent first sand boxes 22 and second sand boxes 23.

[0045] See Figure 2 An oxygen pump 24 is installed on the side wall of the cultivation area 6 of the biological sediment culture tank. In this embodiment, four pumps are used, but other numbers can be used in other embodiments. The nutrient solution submerges the "clean sand," that is, during the simulated submersion period, air is injected into the nutrient solution using the oxygen pump 24. More air passing through the nutrient solution will result in more oxygen dissolving into the nutrient solution, preventing the microorganisms from dying due to lack of oxygen during the cultivation process.

[0046] A method for cultivating biological sediment under simulated tidal conditions includes the following steps:

[0047] S1, go to the tidal flat site for observation; survey and record the slope of the tidal flat, the alternation period between the submerged and exposed periods during a tidal process, the time of day-night alternation, and the average daily sunlight intensity of the tidal flat; and collect several surface sediment and seawater samples rich in algae and bacteria from the tidal flat site.

[0048] S2, based on the data obtained from on-site observations, the tilt angle of the biological sediment culture tank is adjusted by the angle adjustment device 2 to make it close to the slope of the natural tidal flat; the height of the lamp tube 20 is adjusted by the support unit 19 to make the light intensity received by the biological sediment culture tank close to the average daily light intensity recorded by observation; the average salinity, total nitrogen and total phosphorus content of several seawater samples are analyzed in the laboratory, and a nutrient solution with the same salinity, total nitrogen and total phosphorus content characteristics as seawater is prepared;

[0049] S3: Take 50.0g of sediment sample and place it in a container. Add 200ml of deionized water and stir for 15 minutes. Centrifuge at 3000g for 15 minutes to separate large particles of sediment and other impurities from the liquid. The liquid after separation of large particles of impurities is the supernatant. Take the supernatant and filter it to remove a small amount of unseparated impurities. The filtered supernatant is the leachate. Pour the leachate into a 500ml glass container and add the nutrient solution prepared in step S2 to 500ml. Aerate the nutrient solution using an oxygen pump and incubate under a lamp for 3-5 days. Change the liquid in the glass container 1-2 times during this period to obtain the microbial enrichment solution.

[0050] In S3, the method for changing the liquid in the glass container is as follows: pour out half of the liquid in the glass container, and then add an equal amount of nutrient solution to the glass container.

[0051] S4, Sanding: Set the number of sand boxes according to the experimental purpose; place the same number of first sand boxes 22 and second sand boxes 23 respectively, and fill each first sand box 22 and second sand box 23 with clean sand, which is mud sand that does not contain microorganisms; add water to each first sand box 22 and second sand box 23 until it just submerges the clean sand, this is to moisten the clean sand; after the mud sand in the first sand box 22 and second sand box 23 is completely moistened, smooth the surface;

[0052] S5, Microbial Adsorption: Close solenoid valve two, turn on the water pump, and input nutrient solution into the biological sediment culture tank. After the total liquid level of the nutrient solution and water reaches the height of the water level sensor, turn off the water pump; pour the microbial enrichment solution prepared in step S3 into the biological sediment culture tank and stir with a glass rod to make the microbial enrichment solution evenly diffuse to the liquid level in the biological sediment culture tank in S5; turn on the lamp and oxygen pump, the lamp illuminates the liquid in the biological sediment culture tank at this time, and the oxygen pump oxygenates the liquid in the biological sediment culture tank; let it stand for 1-2 days to allow the microorganisms to adapt to the laboratory culture conditions and be able to attach and grow on the clean sand surface in each sand box. During the standing period, change the liquid in the biological sediment culture tank once;

[0053] The method for changing the liquid in the biological sediment culture tank in S5 is to pour out half of the liquid in the biological sediment culture tank and then add an equal amount of nutrient solution.

[0054] S6, Cultivation by Operating the Device: After the settling phase in S5, all equipment is turned on to begin cultivation. First, solenoid valve 17 is opened, and all liquid in the cultivation tank is discharged into the waste liquid tank 16 by gravity (completed within a few minutes), then solenoid valve 17 is closed. At this time, the cultivation tank simulates an exposed period, which lasts for a period of time (several hours). After solenoid valve 17 is closed, timer switch 18 starts timing, and the duration of the simulated exposed period is the same as the natural exposed period. After the simulated exposed period ends (timer switch 18 reaches its set time), water pump 12 is controlled by timer switch 14 to open and close solenoid valve 17. Water pump 12 inputs nutrient solution into the biological sediment cultivation tank up to the height of water level sensor 11 and then closes again (completed within a few minutes), simulating the submersion period. When the water level sensor 11 is reached, timer switch 14... 14. Timing: The flooding period lasts for a period of time (several hours), and the length of the flooding period is the same as the natural flooding cycle. After the flooding period ends, the timing switch 14 reaches its time limit. The lamp 20 is controlled by the timing switch 3 21 to operate automatically according to the day-night cycle, so that the clean sand in the biological sediment cultivation tank is periodically in both light and dark environments. The duration of the day-night cycle is the same as the duration of day and night in nature. The opening and closing pattern of the lamp 20 is the same as the day-night cycle in nature. Specifically, the opening and closing of the lamp 20 is consistent with the alternation of day and night in nature.

[0055] S7, Sampling and Analysis: During the cultivation of biological sediment, one of the first sandbox 22 and one of the second sandbox 23 are taken out periodically as needed. The biological sediment in the first sandbox 22 is used to analyze the various physicochemical and biological properties of the sediment. The second sandbox 23 is placed in a straight flushing tank for a start-up flushing experiment to study its start-up characteristics.

[0056] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined according to the scope of the claims.

Claims

1. A biological sediment cultivation device simulating tidal action, comprising a base plate, characterized in that, A culture tank is provided above the base plate, and a biological sediment culture tank is provided in the culture tank; a first sand box and a second sand box for loading clean sand are placed in the biological sediment culture tank. The base plate is equipped with an angle adjustment device and an adjustment shaft for adjusting the tilt angle of the culture tank. The angle adjustment device and the adjustment shaft are located at both ends of the culture tank. The culture tank is rotatably connected to the base plate through the adjustment shaft. Driven by the angle adjustment device, the culture tank rotates by the adjustment shaft. The culture tank is connected to a water inlet pipe. One end of the water inlet pipe is connected to the biological sediment culture tank, and the other end is connected to a nutrient solution tank. A water pump is installed on the water inlet pipe to drive the nutrient solution into the biological sediment culture tank. A water level sensor is fixed on the inner wall of the biological sediment culture tank. The water pump is connected to a timer switch. A solenoid valve is installed on the water inlet pipe. The water level sensor is electrically connected to the water pump, the timer switch, and the solenoid valve. The culture tank is connected to a water outlet pipe. One end of the water outlet pipe is connected to the biological sludge culture tank, and the other end is connected to a waste liquid tank. A second solenoid valve is installed on the water outlet pipe. The second solenoid valve is connected to a second timer switch. A lamp tube is installed above the culture tank, and a support unit is provided on the culture tank to raise the height of the lamp tube. The lamp tube is connected to a timer switch. The biological sediment culture tank is divided into a culture area and a water inlet buffer zone. The first sand box and the second sand box are placed in the culture area. The water inlet pipe and the water outlet pipe are connected to the water inlet buffer zone. An upper energy dissipation plate is fixed on the inner wall of the water inlet buffer zone, and the lower end of the upper energy dissipation plate does not contact the lower end of the water inlet buffer zone.

2. The biological sediment cultivation device simulating tidal action according to claim 1, characterized in that, The lower surface wall of the water inlet buffer zone is lower than the lower surface wall of the culture zone, and the intersection of the lower surface wall of the water inlet buffer zone and the lower surface wall of the culture zone is set as a slope, which is called the lower energy dissipation slope.

3. The biological sediment cultivation device simulating tidal action according to claim 2, characterized in that, The lower surface wall of the cultivation area is fixed with a first support and a second support for fixing the first sandbox and the second sandbox. Viewed from above, the first support is L-shaped; the upper surface of the first support is cut downward to form an L-shaped first locking part, and the two ends of the first locking part extend to the two ends of the first support respectively; the inner side of the first locking part extends to the inner side of the first support; the outer edge of the corner of the first sandbox or the second sandbox is in contact with the side wall of the first locking part. Viewed from above, the second support is in the shape of a cross, and it consists of four first supports; the outer edges of the four first supports are in contact with each other and are fixedly connected.

4. The biological sediment cultivation device simulating tidal action according to claim 2, characterized in that, An oxygenation pump for providing oxygen to microorganisms is fixed on the inner wall of the culture zone.

5. A method for cultivating biological sediment under simulated tidal conditions, used in the biological sediment cultivation device under simulated tidal conditions as described in any one of claims 1-4, characterized in that, Includes the following steps, S1: Go to the tidal flat site for observation; survey and record the slope of the tidal flat, the alternation period between the submerged and exposed periods during a tidal process, the time of day-night alternation, and the average daily sunlight intensity of the tidal flat; and collect several surface sediment and seawater samples rich in algae and bacteria from the tidal flat site. S2: Based on the data obtained in S1, adjust the tilt angle of the biological sediment culture tank using an angle adjustment device to make it close to the slope of the tidal flat; adjust the height of the lamp tube using a support unit to make the light intensity received by the biological sediment culture tank close to the daily average light intensity recorded in the observation; analyze the salinity, total nitrogen, and total phosphorus content of the seawater sample in the laboratory, and prepare a nutrient solution with the same salinity, total nitrogen, and total phosphorus content characteristics as seawater. S3: Take 50.0g of mud and sand sample and put it into a container. Add 200ml of deionized water and stir for 15min. Centrifuge at 3000g for 15min to separate large particles of impurities from the liquid. The liquid after separation from large particles of impurities is the supernatant. Take the supernatant, filter out a small amount of unseparated impurities to obtain the leachate of the mud and sand sample; pour the leachate into a 500ml glass container, add the nutrient solution prepared in step S2 to 500ml, aerate the nutrient solution using an oxygen pump, and incubate under a lamp for 3-5 days; during this period, change the liquid in the glass container 1-2 times to obtain the microbial enrichment solution; in S3, the method of changing the liquid in the glass container is: pour out half of the liquid in the glass container, and then add an equal amount of nutrient solution to the glass container; S4: Place an equal number of first and second sand boxes in the cultivation area. Spread clean sand in each first and second sand box, and add water to each first and second sand box until the clean sand is just submerged. After the clean sand in the first and second sand boxes is completely wetted, smooth the surface of the clean sand. S5: Close solenoid valve 2 and turn on the water pump to input nutrient solution into the biological sediment culture tank. After the total liquid level of nutrient solution and water reaches the height of the water level sensor, turn off the water pump. At this time, the total liquid level of nutrient solution and water is higher than the surface of the clean sand. Pour the microbial enrichment solution prepared in step S3 into the biological sediment culture tank and stir with a glass rod to make the microbial enrichment solution evenly diffuse into the total liquid level of nutrient solution and water in S5. Turn on the lamp and oxygen pump. The lamp illuminates the liquid in the biological sediment culture tank at this time, and the oxygen pump oxygenates the liquid. Let it stand for 1-2 days to allow the microorganisms to adapt to the laboratory culture conditions and be able to attach and grow on the surface of the clean sand in each sand box. Change the liquid in the biological sediment culture tank once during the standing period. The way to change the liquid in the biological sediment culture tank in S5 is to pour out half of the liquid in the biological sediment culture tank and then add an equal amount of nutrient solution. S6: After the settling phase in S5 is completed, open solenoid valve two; after all the liquid in the biological sediment culture tank is discharged into the waste liquid tank by gravity, solenoid valve two is closed; the biological sediment culture tank simulates the exposed beach period and lasts for a period of time, the length of which is the same as the natural exposed beach period; after the simulated exposed beach period ends, open solenoid valve one, turn on the water pump and close solenoid valve two, the water pump inputs nutrient solution into the biological sediment culture tank to the height of the water level sensor and then closes, simulating the submersion period and lasting for a period of time, the length of which is the same as the natural submersion period; after the simulated submersion ends, open solenoid valve two; the lamp opening and closing time is the same as the day-night cycle time, and the lamp opening and closing pattern is the same as the natural day-night cycle pattern.

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