Experimental device for simulating nitrogen and phosphorus release of lake sediment

Abstract

The utility model discloses an experimental device for simulating the release of nitrogen and phosphorus in lake sediment, which comprises a base, a shell, a disturbance system and a control system, and is characterized in that the base is positioned at the bottom of the device and provides a stable platform for the operation of the device; the shell is a hollow cylinder and is arranged on the base; the disturbance system is arranged in the shell, and the control system is connected with the disturbance system and controls operation of the disturbance system. The experimental device for simulating the nitrogen and phosphorus release of the lake bottom mud is small in occupied area and convenient to carry and transport, the shell part is detachable, the bottom mud and a water body can be conveniently and rapidly filled, the early-stage preparation work efficiency is improved, the hydrodynamic condition in the lake can be quantitatively simulated, and therefore the nitrogen and phosphorus release rate in the bottom mud can be accurately obtained; the method has important practical significance and application value for promoting the development of a river and lake water system communication technology and improving the water environment quality.

Description

Technical Field

[0001] The utility model belongs to the technical field of water environment pollution control, and in particular relates to an experimental device for simulating the release of nitrogen and phosphorus in lake bottom mud. Background Art

[0002] With the increasing scarcity of global water resources and the continuous deterioration of water environment quality, water ecological health has become the focus of people's attention. In this context, the importance of river and lake water system connectivity has gradually become prominent. River and lake water system connectivity not only helps the rational allocation and utilization of water resources, but also enhances the self-purification capacity of water bodies, which is of great significance for improving water environment quality.

[0003] However, in the process of connecting rivers and lakes, the hydrodynamic conditions of lakes will change significantly. These changes will directly affect the release rate of nutrients such as nitrogen and phosphorus in lake sediments. When the release rate of nitrogen and phosphorus is too fast, it often leads to serious water quality exceeding the standard, which in turn causes a series of environmental problems such as eutrophication of water bodies.

[0004] In order to deeply study the mechanism of nitrogen and phosphorus release during the connection of river and lake water systems, researchers usually need to use experimental devices to conduct simulation experiments. However, there are some common problems with the existing nitrogen and phosphorus release research devices. On the one hand, some devices occupy too much space, which not only has high construction costs, but is also inconvenient to move and deploy, and is difficult to promote in practical applications. On the other hand, although some devices are small in size, they are insufficient in simulating hydrodynamic conditions and cannot accurately and quantitatively simulate the hydrodynamic conditions during the actual connection of river and lake water systems, resulting in a large difference between the experimental results and the actual situation, making it difficult to provide a strong scientific basis for the optimization of river and lake water system connectivity. Utility Model Content

[0005] In view of the deficiencies in the prior art, the utility model provides an experimental device for simulating the release of nitrogen and phosphorus from lake sediments. The device has a small footprint and is easy to operate. It can quantitatively simulate the hydrodynamic conditions in lakes, thereby accurately obtaining the release rate of nitrogen and phosphorus in sediments.

[0006] The utility model is realized through the following technical solutions:

[0007] An experimental device for simulating the release of nitrogen and phosphorus from lake sediments, comprising a base, a shell, a disturbance system and a control system, wherein the base is located at the bottom of the device and provides a stable platform for the operation of the device; the shell is a hollow cylinder and is arranged on the base; the disturbance system is arranged inside the shell, and the control system is connected to and controls the operation of the disturbance system;

[0008] The shell is divided into three sections, namely, the bottom mud section, the water section and the motor section from bottom to top, and the three sections are independent of each other and connected by flanges; a water intake is provided on the outer wall of the shell at the water section; the top and bottom of the motor section are sealed, and a hole is provided at the bottom;

[0009] The disturbance system comprises a motor, a transmission shaft and a stirring device, wherein the output shaft of the motor is connected to the transmission shaft, and the end of the transmission shaft is connected to the stirring device; the motor is arranged in the motor section, and the transmission shaft penetrates into the water section through the hole; the stirring device is located in the water section and above the bottom mud section;

[0010] The control system controls the operation of the disturbance system by controlling the operation of the motor.

[0011] Preferably, the diameter of the shell is 10 cm, the height of the motor section is 20 cm, the height of the water section is 30 cm, and the height of the bottom mud section is 20 cm.

[0012] Preferably, a support is provided at the bottom of the motor section, the motor is arranged on the support, and a hole is opened at the bottom of the support corresponding to the position of the hole.

[0013] Preferably, the height of the support is 5 cm.

[0014] Preferably, the stirring device is a propeller.

[0015] Preferably, the propeller has a blade length of 2.5 cm and is located 4 cm above the bottom mud section.

[0016] Preferably, the number of the water intakes is more than one, which are evenly distributed longitudinally on the outer wall of the shell, and the interval between two adjacent water intakes is 6 cm.

[0017] Preferably, a water stop valve is provided at the water intake.

[0018] Preferably, the shell is made of transparent material.

[0019] Preferably, the motor is further provided with a dial, the top of the motor section is open, and the dial is connected to the motor through the top opening of the motor section.

[0020] The beneficial effects of the utility model are as follows:

[0021] (1) The experimental device of the utility model has a total height of 80 cm and a diameter of 10 cm, occupies a small area, and is easy to carry and transport.

[0022] (2) The experimental device of the utility model can disassemble the device shell through the flange and bolts, so as to quickly fill the bottom mud and water, thereby improving the efficiency of the preliminary preparation work.

[0023] (3) In the experimental device of the utility model, multiple water intakes are provided at the water section, which can eliminate the influence of the uneven distribution of nitrogen and phosphorus released from lake sediment along the water depth direction on the concentration test results.

[0024] (4) In the experimental device of the utility model, the stirring device is located 4 cm above the bottom mud section, which ensures the uniformity of the shear velocity of the bed surface. The height of the bottom mud section is 20 cm, which avoids the output end power of the stirring device acting on the bracket due to the bottom mud section being too low, thereby ensuring the accuracy of simulating the nitrogen and phosphorus release process of the lake bottom mud.

[0025] (5) The experimental device of the utility model establishes the corresponding relationship between the motor control system, the rotation speed and the shear velocity of the bed layer by means of the rotation speed measuring device and the observation of the sediment start-up, thereby achieving a quantitative and accurate simulation of the hydrodynamic conditions when nitrogen and phosphorus are released from the lake bottom mud. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 Schematic diagram of the overall structure of the experimental device for simulating nitrogen and phosphorus release from lake sediments (the dimensions in the figure are in mm);

[0027] Figure 2 is a schematic diagram of the structure of the shell;

[0028] Figure 3 It is the structural diagram of the disturbance system;

[0029] Figure 4 It is the structural diagram of the motor section;

[0030] Figure 5 It is a schematic diagram of the structure of the flange.

[0031] In the figure: 1. base; 2. shell; 2-1. sediment section; 2-2. water section; 2-3. motor section; 2-4. hole; 3. disturbance system; 3-1. stirring device; 3-2. transmission shaft; 3-3. motor; 3-4. dial; 3-5. power cord; 4. water intake; 5. water stop valve; 6. flange; 6-1. screw hole; 7. support. DETAILED DESCRIPTION

[0032] The utility model is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0033] In the description of the present invention, terms indicating orientation or positional relationship, such as "top", "bottom", "inside", "outside", "front" and "back", are only based on the orientation shown in the drawings for the convenience of describing the present invention, and do not indicate or imply that the device referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0034] Example 1

[0035] An experimental device simulating the release of nitrogen and phosphorus from lake sediments, such as Figure 1 As shown, it includes a base 1, a shell 2, a disturbance system 3 and a control system, wherein the base 1 is located at the bottom of the device, providing a stable platform for the operation of the entire device; the shell 2 is a hollow cylinder, which is arranged on the base to provide a closed space for the bottom mud and water body during the experiment; the disturbance system 3 is arranged inside the shell 2, and the control system is connected to and controls the operation of the disturbance system 3.

[0036] like Figure 2 As shown, the housing 2 is divided into three sections, namely, from bottom to top, the bottom mud section 2-1, the water section 2-2 and the motor section 2-3, the three sections are independent and connected by flanges 6; a water intake 4 is provided on the outer wall of the housing 2 at the water section 2-2; the top and bottom of the motor section 2-3 are sealed, and a hole 2-4 is provided at the bottom. There is no shielding between the bottom mud section 2-1 and the water section 2-2.

[0037] like Figure 1 , 2 As shown in FIG. 5 , the flange 6 is provided with a screw hole 6-1, and the bottom mud section 2-1, the water section 2-2 and the motor section 2-3 are fixedly connected through the screw hole 6-1 and corresponding bolts and can be disassembled, so as to realize the rapid filling of the bottom mud and the water body and speed up the preliminary preparation process of the experiment.

[0038] like Figure 2 As shown, there are three water intakes 4, which are evenly distributed longitudinally on the outer wall of the shell 2, close to the top of the water body section 2-2. A water stop valve 5 is provided at the water intake 4. The water stop valve 5 is closed during the disturbance. After the disturbance is over, the water stop valve 5 is opened to take water with a test tube to complete the test and analysis of nitrogen and phosphorus concentrations.

[0039] like Figure 1 , 3As shown in , 4, the disturbance system 3 includes a motor 3-3, a transmission shaft 3-2 and a stirring device 3-1, the output shaft of the motor 3-3 is connected to the transmission shaft 3-2, and the end of the transmission shaft 3-2 is connected to the stirring device 3-1; the motor 3-3 is arranged in the motor section 2-3, and the transmission shaft 3-2 penetrates into the water section 2-2 through the hole 2-4; the stirring device 3-1 is located in the water section 2-2 and above the bottom mud section 2-1, providing stable and uniform hydrodynamic conditions.

[0040] like Figure 4 As shown, a support 7 is provided at the bottom of the motor segment 2-3, and the motor 3-3 is arranged on the support 7. The bottom opening of the support 7 corresponds to the position of the hole 2-4, allowing the transmission shaft 3-2 to pass through the motor segment 2-3 to transmit the output power of the motor 3-3 to the stirring device 3-1, thereby ensuring the integrity of the motor segment 2-3 when it is disassembled.

[0041] like Figure 1 As shown, the height of the base 1 is 10 cm, the shell 2 is a transparent POM plastic with a diameter of 10 cm; the height of the motor section 2-3 is 20 cm, and the height of the support 7 is 5 cm; the height of the water section 2-2 is 30 cm, and on the outer wall of the shell 2 where it is located, starting from 6 cm from the top of the water section 2-2, a water intake 4 is set every 6 cm in the longitudinal direction; the height of the sediment section 2-1 is 20 cm, and the stirring device 3-1 is a propeller with a blade length of 2.5 cm, located 4 cm above the sediment section 2-1.

[0042] like Figure 3As shown, the motor 3-3 is also provided with a dial 3-4, the top of the motor section 2-3 is open, and the dial 3-4 is connected to the motor 3-3 through the top opening of the motor section 2-3, and is used to control and record the speed data of the motor 3-3. The control system is a PLC system that sets a programming method, which is a method for quantitatively and accurately simulating the hydrodynamic conditions when nitrogen and phosphorus are released from lake sediments: first, the speed of the motor 3-3 is measured by a speed measuring device, and the accurate speed value corresponding to different adjustment degrees of the motor original speed control device is obtained, and it is matched with the dial 3-4, so as to achieve accurate adjustment of the speed. Secondly, by placing sediment of different particle sizes in the bottom mud section 2-1, adjusting the rotation speed from small to large, and recording the rotation speed value corresponding to the starting of the sediment, the sediment of different particle sizes corresponds to different starting flow rates, and the scatter point correspondence relationship between the bed surface shear flow velocity and the motor speed value can be obtained. After the least squares analysis and processing, the functional relationship with the bed surface shear flow velocity as the dependent variable and the motor speed as the variable can be obtained, thereby realizing the quantitative and accurate simulation of the hydrodynamic conditions when the nitrogen and phosphorus in the lake bottom mud are released. The theory and technology of motor speed measurement have been developed to be relatively mature, and will not be repeated in this utility model.

[0043] The operating process of the above experimental device for simulating nitrogen and phosphorus release from lake sediments is as follows:

[0044] (1) The first step is to quantitatively and accurately simulate the hydrodynamic conditions of nitrogen and phosphorus release in lake sediments, that is, to determine the functional relationship between the shear flow velocity of the bed layer and the motor speed:

[0045] The speed is accurately engraved on the dial 3-4 by the speed measuring device to achieve accurate measurement of the speed. First, the water section 2-2 and the motor section 2-3 are disassembled separately through the flange 6, and the sediment particles of different particle sizes are filled in the sediment section 2-1, and then the sediment section 2-1 and the water section 2-2 are connected through the flange 6, and water is added to the water section 2-2, and then the water section 2-2 and the motor section 2-3 are connected through the flange 6. The speed of the motor 3-3 is adjusted to the minimum through the dial 3-4, and the power cord 3-5 is connected to the power supply, and the speed is adjusted from small to large until the sediment particles in the sediment section 2-1 start, indicating that the sediment particles reach the starting flow rate, and the motor speed at this time is recorded, and a set of point data corresponding to the shear flow velocity of the bed layer and the motor speed can be obtained. Repeat the above steps to obtain array data. Then the scattered data can be converted into a functional relationship by the least squares method. After determining the functional relationship, the above steps should be repeated to verify the fitted functional relationship with sediments of other particle sizes to ensure that the error is within the allowable range. From basic professional knowledge, it can be known that the increase in the shear velocity of the bed layer should be proportional to the motor speed. The functional relationship between the shear velocity of the bed layer and the motor speed is as follows:

[0046] u *=a×(propeller speed)+b

[0047] Where: u * is the shear velocity of the bed surface (m / s); the propeller speed is the motor speed (rpm); a and b are unknown coefficients determined by experiments.

[0048] The above operations complete the setting of the control system in the device.

[0049] (2) Next, we describe how to simulate the release of nitrogen and phosphorus from lake sediments using a device:

[0050] First, the water section 2-2 and the motor section 2-3 are disassembled separately through the flange 6, and the sediment sample collected in advance is filled into the sediment section 2-1, and then the sediment section 2-1 and the water section 2-2 are connected through the flange 6, and water is added to the water section 2-2, and then the water section 2-2 and the motor section 2-3 are connected through the flange 6. The speed of the motor 3-3 is adjusted to the minimum through the dial 3-4, the power cord 3-5 is connected to the power supply, and the speed of the dial 3-4 is adjusted to the lake hydrodynamic conditions required to be simulated in the experiment. After the speed stabilizes, the water stop valve 5 is opened, and water is taken from the water inlet 6 with a test tube. The nitrogen and phosphorus concentrations in the water body are measured by the ultraviolet spectrophotometer and recorded. After that, the above steps are repeated, and the dial 3-4 is adjusted from small to large to reach the speed corresponding to the hydrodynamic conditions required for simulation.

[0051] (3) After completing the nitrogen and phosphorus release simulation study of a sediment sample, the water section 2-2 and the motor section 2-3 can be disassembled separately through the flange 6, and the sediment section 2-1 can be cleaned. After cleaning, the above steps can be repeated to perform nitrogen and phosphorus release simulation studies on different sediment samples.

[0052] Finally, it should be noted that the above description is only a preferred embodiment of the utility model and is not intended to limit the utility model. For those skilled in the art, they can still modify the technical solutions recorded in the above embodiments, or replace some of the technical features therein with equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the utility model shall be included in the protection scope of the utility model.

Claims

1. An experimental device for simulating the release of nitrogen and phosphorus from lake sediments, characterized in that: The device comprises a base, a shell, a disturbance system and a control system, wherein the base is located at the bottom of the device and provides a stable platform for the operation of the device; the shell is a hollow cylinder and is arranged on the base; the disturbance system is arranged inside the shell, and the control system is connected to and controls the operation of the disturbance system; The shell is divided into three sections, namely, the bottom mud section, the water section and the motor section from bottom to top, and the three sections are independent of each other and connected by flanges; a water intake is provided on the outer wall of the shell at the water section; the top and bottom of the motor section are sealed, and a hole is provided at the bottom; The disturbance system comprises a motor, a transmission shaft and a stirring device, wherein the output shaft of the motor is connected to the transmission shaft, and the end of the transmission shaft is connected to the stirring device; the motor is arranged in the motor section, and the transmission shaft penetrates into the water section through the hole; the stirring device is located in the water section and above the bottom mud section; The control system controls the operation of the disturbance system by controlling the operation of the motor.

2. The experimental device for simulating the release of nitrogen and phosphorus from lake sediments according to claim 1, characterized in that: The diameter of the shell is 10 cm, the height of the motor section is 20 cm, the height of the water section is 30 cm, and the height of the bottom mud section is 20 cm.

3. An experimental device for simulating the release of nitrogen and phosphorus from lake sediments according to claim 2, characterized in that: A support is provided at the bottom of the motor section, the motor is arranged on the support, and a hole is opened at the bottom of the support, corresponding to the position of the hole.

4. The experimental device for simulating the release of nitrogen and phosphorus from lake sediments according to claim 3, characterized in that: The height of the support is 5 cm.

5. The experimental device for simulating the release of nitrogen and phosphorus from lake sediments according to claim 2, characterized in that: The stirring device is a propeller.

6. The experimental device for simulating the release of nitrogen and phosphorus from lake sediments according to claim 5, characterized in that: The propeller blade has a length of 2.5 cm and is located 4 cm above the bottom mud section.

7. The experimental device for simulating the release of nitrogen and phosphorus from lake sediments according to claim 2, characterized in that: The number of the water intakes is more than one, and they are evenly distributed longitudinally on the outer wall of the shell, and the interval between two adjacent water intakes is 6 cm.

8. The experimental device for simulating the release of nitrogen and phosphorus from lake sediments according to claim 7, characterized in that: A water stop valve is provided at the water intake.

9. The experimental device for simulating the release of nitrogen and phosphorus from lake sediments according to claim 1, characterized in that: The shell is made of transparent material.

10. The experimental device for simulating the release of nitrogen and phosphorus from lake sediments according to claim 1, characterized in that: The motor is also provided with a dial, the top of the motor section is open, and the dial is connected to the motor through the top opening of the motor section.

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