Experimental Device and Method for the Influence of Irrigation Return Flow on the Migration of Substances at the Sediment-Water Interface

Abstract

The present invention relates to an experimental device and method for the influence of irrigation return flow on the migration of substances at the sediment-water interface, which is characterized in that it includes an experimental box, a partition chamber and a partition net plate; the specific experimental method is as follows: S1: Static experiment; S2: Dynamic experiment; by loading sediment and overlying water into the second test chamber of the experimental box, directly simulating the migration and transformation of nutrients at the sediment-water interface under static environmental conditions; by loading sediment and overlying water into the second test chamber of the experimental box, and loading saline soil into the first test chamber, and using flowing groundwater to simulate the migration and transformation of nutrients at the sediment-water interface under dynamic disturbance environmental conditions; thereby studying the migration diffusion concentration and flux of nutrients at the sediment-water interface, and simultaneously studying the nutrient exchange amounts of different layers of the overlying water.

Description

Technical Field

[0001] The present invention relates to the technical field of sediment-water interface material migration, and particularly to an experimental device and method for the influence of irrigation return water on sediment-water interface material migration. Background Art

[0002] Lakes and the like often undergo natural disturbances such as wind and biology, as well as artificial hydraulic disturbances such as ships passing by. Shallow lakes are more significantly affected by disturbances. After wind disturbance or hydraulic disturbance, the sediment in the water body becomes suspended. Changes in water environment factors such as light, temperature, and hydrodynamic force often lead to easier release of endogenous pollutants in the sediment, and will also change the endogenous diffusion flux and release rate of nutrients such as nitrogen and phosphorus in the sediment.

[0003] The endogenous pollution of sediment is an important factor affecting lake water quality. The diffusion flux and release rate of endogenous pollution are important research topics for lake eutrophication. Currently, there are mainly two types of research in this regard: one is to collect surface sediment with a grab sampler, add the collected natural water sample or prepared water for a shaking flask simulation experiment, and calculate the migration and diffusion flux of the surface sediment at different points; the other is to collect columnar sediment, bring it back to the laboratory for layering treatment, and at the same time add the collected natural water sample or prepared water for a shaking flask simulation experiment, and calculate the migration and diffusion flux at different depths at the same point. The sediment collected by these two methods and the simulation experiments can meet the diffusion flux and release rate of endogenous pollution when some water quality changes or environmental factors change, but for the changes brought about by wind disturbance or hydraulic disturbance, these methods cannot be achieved. Because this method cannot simulate the influence of wind disturbance or hydraulic disturbance on the endogenous diffusion flux and release rate of nutrients such as nitrogen and phosphorus.

[0004] Currently, the existing experimental devices and methods (201310342721.6) for studying the exchange flux of sediment layered nutrients mainly study the diffusion flux of different layers of interstitial water under static conditions, while the release of endogenous nutrients in sediment is also affected by the sediment resuspension process caused by various disturbance conditions; an existing experimental device and experimental method (201811152322.2) for simulating the migration and transformation behavior of pollutants in nearshore water-sediment mainly uses a peristaltic pump to introduce water into the mud-water exchange container to simulate the flow of the actual water body, while natural conditions not only involve the flow state, but also different environmental conditions such as temperature, dissolved oxygen, and pH will affect the release of endogenous nutrients in sediment.

[0005] Therefore, to solve the above technical problems, it is indeed necessary to adopt an experimental device and method for the influence of irrigation return water on sediment-water interface material migration to overcome the defects in the prior art. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to provide an experimental device and method for studying the influence of irrigation return flow on the migration of substances at the sediment-water interface. The device and method can simulate the migration of substances at the sediment-water interface under static and dynamic conditions, and can also be used to explore the changes in the diffusion flux of endogenous nutrients under different conditions.

[0007] To solve the above technical problem, the technical solution of the present invention is: an experimental device for studying the influence of irrigation return flow on the migration of substances at the sediment-water interface, the innovation of which lies in: including an experimental box, a partition chamber and a partition net plate;

[0008] The experimental box is in the shape of a cuboid and is transparent with an open top. The two side faces of the experimental box in the length direction are the water inlet surface and the water outlet surface respectively. A baffle is arranged in the experimental box near the water outlet surface and is parallel to the water outlet surface. A first groundwater chamber is formed between the right side of the baffle and the water outlet surface of the experimental box;

[0009] The partition chamber is in the shape of a cuboid and covers the inside of the experimental box with a closed top. A partition is arranged vertically in the partition chamber to divide the partition chamber into a left chamber and a second groundwater chamber. A first test chamber is formed between the left side of the left chamber and the water inlet surface of the experimental box. A second test chamber is formed between the right side of the second groundwater chamber and the baffle of the experimental box;

[0010] The partition net plate includes a first partition net plate and a second partition net plate. The first partition net plate is horizontally arranged in the first test chamber, and the circumference of the first partition net plate is respectively connected to the inner wall of the experimental box and the outer wall of the left chamber. The second partition net plate is horizontally arranged in the second test chamber, and the circumference of the second partition net plate is respectively connected to the outer wall of the second groundwater chamber, the inner wall of the experimental box and the baffle. A group of holes communicating with the second test chamber is arranged on the part of the right side wall of the second groundwater chamber below the second partition net plate. A group of holes communicating the second test chamber with the first groundwater chamber is arranged on the part of the baffle below the second partition net plate;

[0011] An overlying water inlet is arranged on the water inlet surface of the experimental box above the first partition net plate and near the top of the experimental box. A groundwater inlet is arranged on the water inlet surface of the experimental box below the first partition net plate. A groundwater outlet is arranged on the water outlet surface of the experimental box below the second partition plate;

[0012] A groundwater conduction port is respectively arranged on the left and right chamber walls of the left chamber of the partition chamber, and the groundwater conduction ports are located below the first partition net plate. The groundwater conduction ports on the partition chamber are connected by a hose.

[0013] Further, the height of the partition chamber is lower than the height of the experimental box, and the height of the baffle is equal to the height of the water outlet surface of the experimental box.

[0014] Furthermore, sediments are provided on the second partition net plate.

[0015] Furthermore, saline soil is provided on the first partition net plate, and sediments are provided on the second partition net plate.

[0016] Test method for the influence of irrigation return flow on the migration of substances at the sediment-water interface. The innovation lies in: the specific test method is as follows:

[0017] S1: Static test: Select the sediments to be laid on the second partition net plate, and the thickness of the sediments is 4 - 5 cm; disconnect the hose in the left chamber, add overlying water to the second test chamber, and the thickness of the overlying water is 20 - 25 cm and does not exceed the height of the partition chamber; the test lasts for ten days, and sampling is carried out at the same time every day. The water sample is taken from the water sample 5 - 10 cm above the sediment interface, 12 ml is extracted each time, and the total phosphorus content and the dissolved inorganic phosphorus content are measured; the sediment sample is taken from the sediment 1 cm below the sediment interface, 1 - 2 g is taken each time, and is used for the measurement and analysis of phosphorus forms.

[0018] S2: Dynamic test: Select the sediments to be laid on the second partition net plate, and the thickness of the sediments is 4 - 5 cm; select the saline soil to be laid on the first partition net plate, and the thickness of the saline soil is 10 - 15 cm; connect the hose in the left chamber; inject overlying water into the first test chamber through the overlying water inlet, the overlying water is 20 - 25 cm above the saline soil interface, and the overlying water overflows into the second test chamber through the partition chamber, so that the water surface is higher than the partition chamber; inject groundwater into the first test chamber through the groundwater inlet, and the groundwater flows into the second groundwater chamber through the hose, then flows into the second test chamber through the pore group, then flows into the first groundwater chamber through the pore group, and finally discharges through the groundwater outlet; the test lasts for ten days, and sampling is carried out at the same time every day. The water sample is taken from the water sample 5 - 10 cm above the sediment interface, 12 ml is extracted each time, and the total phosphorus content and the dissolved inorganic phosphorus content are measured; the sediment sample is taken from the sediment 1 cm below the sediment interface, 1 - 2 g is taken each time, and is used for the measurement and analysis of phosphorus forms.

[0019] The advantages of the present invention are as follows:

[0020] 1) In the present invention, by loading sediments and overlying water into the second test chamber of the test box, the migration and transformation of nutrients at the sediment-water interface under static environmental conditions are directly simulated; by loading sediments and overlying water into the second test chamber of the test box, and loading saline soil into the first test chamber, and using flowing groundwater, the migration and transformation of nutrients at the sediment-water interface under dynamic disturbance environmental conditions are simulated; thereby studying the migration diffusion concentration and flux of nutrients at the sediment-water interface, and simultaneously studying the nutrient exchange amount of different layers of overlying water. Description of the Drawings

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

[0022] Figure 1 It is a structural diagram of an experimental device for the influence of irrigation return water on the migration of substances at the sediment-water interface of the present invention.

[0023] Figures 2 to 4 It is a static test diagram of the influence of irrigation return water on the migration of substances at the sediment-water interface of the present invention.

[0024] Figures 5 to 7 It is a structural diagram of a dynamic test of the influence of irrigation return water on the migration of substances at the sediment-water interface of the present invention. Embodiment

[0025] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. Generally, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0026] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0027] As Figure 1 shown, the experimental device for the influence of irrigation return water on the migration of substances at the sediment-water interface includes a test box 1, a partition bin 2 and a partition net plate 3.

[0028] The test box 1 has a rectangular parallelepiped-shaped transparent structure and an open top. The two side surfaces of the test box 1 in the length direction are respectively a water inlet surface 11 and a water outlet surface 12; a baffle 13 is arranged in the test box 1 near the water outlet surface and parallel to the water outlet surface 12, and a first groundwater bin 14 is formed between the right side of the baffle 13 and the water outlet surface 12 of the test box.

[0029] The partition bin 2 has a rectangular parallelepiped shape and is covered in the test box 1 with a closed top. A partition plate 21 is arranged vertically in the partition bin 2 to divide the partition bin 2 into a left bin chamber 22 and a second groundwater bin 23; a first test chamber 24 is formed between the left side of the left bin chamber 22 and the water inlet surface 11 of the test box 1, and a second test chamber 25 is formed between the right side of the second groundwater bin chamber 23 and the baffle 13 of the test box 1.

[0030] The partition net plate 3 includes a first partition net plate 31 and a second partition net plate 32; the first partition net plate 31 is horizontally arranged in the first test chamber 24, and the circumferences of the first partition net plate 31 are respectively connected to the inner wall of the test chamber 1 and the outer wall of the left chamber 22; the second partition net plate 32 is horizontally arranged in the second test chamber 25, and the circumferences of the second partition net plate 32 are respectively connected to the outer wall of the second groundwater storage tank 23, the inner wall of the test chamber 1 and the baffle 13; holes communicating with the second test chamber 25 are arranged in the part of the right chamber wall of the second groundwater storage tank 23 below the second partition net plate 32, and holes communicating the second test chamber 25 with the first groundwater storage tank 14 are arranged in the part of the baffle 13 below the second partition net plate 32.

[0031] An upper overlying water inlet 15 is arranged at a position above the first partition net plate 31 and close to the top of the test chamber 1 on the water inlet surface of the test chamber 1, and a groundwater inlet 16 is arranged below the first partition net plate 31 on the water inlet surface 11 of the test chamber 1; a groundwater outlet 17 is arranged below the second partition plate 32 on the water outlet surface 12 of the test chamber 1.

[0032] A groundwater conduction port 26 is respectively arranged on the left chamber wall and the right chamber wall of the left chamber 22 in the partition chamber 2, and the groundwater conduction port 26 is located below the first partition net plate; the groundwater conduction ports in the partition chamber 2 are connected by a hose 27.

[0033] The height of the partition chamber 2 is lower than the height of the test chamber 1, and the height of the baffle 13 is equal to the water outlet surface of the test chamber 1.

[0034] Sediments are arranged on the second partition net plate 32.

[0035] Saline soil is arranged on the first partition net plate 31, and sediments are arranged on the second partition net plate 32.

[0036] Test method for the influence of irrigation return flow on the migration of substances at the sediment-water interface. The specific test method is as follows:

[0037] S1: Static test: As Figures 2 to 4 shown: A is the overlying water, B is the sediment, and C is the groundwater; select the sediment to be laid on the second partition net plate, and the thickness of the sediment is 4 - 5 cm; disconnect the hose in the left chamber, add overlying water to the second test chamber, and the thickness of the overlying water is 20 - 25 cm and does not exceed the height of the partition chamber; the test lasts for ten days, and samples are taken at the same time every day. The water sample is taken at a position 5 - 10 cm above the sediment interface, and 12 ml is extracted each time, and the total phosphorus content and the dissolved inorganic phosphorus content are measured; the sediment sample is taken from the sediment 1 cm below the sediment interface, and 1 - 2 g is taken each time for the measurement and analysis of phosphorus forms.

[0038] S2: Dynamic test: As Figures 5 to 7 shown: A is overlying water, B is sediment, C is groundwater, and D is saline soil; select the sediment to be laid on the second partition net plate, and the thickness of the sediment is 4 - 5 cm; select the saline soil to be laid on the first partition net plate, and the thickness of the saline soil is 10 - 15 cm; connect the hose in the left chamber; inject overlying water into the first test chamber through the overlying water inlet, the overlying water is 20 - 25 cm higher than the saline soil interface, and the overlying water overflows into the second test chamber through the partition bin, so that the water surface is higher than the partition bin; inject groundwater into the first test chamber through the groundwater inlet, and the groundwater flows into the second groundwater chamber through the hose, then flows into the second test chamber through the hole group, then flows into the first groundwater chamber through the hole group, and finally discharges through the groundwater outlet; the test lasts for ten days, and samples are taken once at the same time every day. The water sample is taken at a position 5 - 10 cm above the sediment interface, and 12 ml is extracted each time, and the total phosphorus content and the content of dissolved inorganic phosphorus are measured; the sediment sample is taken from the sediment 1 cm below the sediment interface, and 1 - 2 g is taken each time for the measurement and analysis of phosphorus forms.

[0039] By comparing the total phosphorus content of the overlying water body at the sediment - water interface under static and dynamic conditions, it is found that its content under static conditions is much greater than that under dynamic conditions, indicating that the disturbance condition accelerates the vertical mixing process of dissolved phosphorus in the overlying water. Thus, compared with the static condition, the total phosphorus content at each time period is at a relatively low level; for the changes in the phosphorus content in the sediment, the overall difference is not particularly large, but the dynamic disturbance also accelerates the diffusion of NaOH - TP at the interface, manifested as the relatively gentle change of its monitored concentration under dynamic conditions, while under static conditions, there are obvious two change peaks on the 2nd day and the 8th day. Among the three phosphorus contents in the sediment, the content of insoluble P is relatively high, and both in the static and dynamic experimental stages, it shows a change process of two peaks and three valleys, indicating that the disturbance has no significant effect on the diffusion process of the insoluble P content in the sediment.

[0040] Through comparative analysis, under the disturbance of irrigation return water entering the lake, the mixing effect of the total phosphorus in the overlying water at the sediment - water interface is accelerated. In addition, it promotes the diffusion of NaOH - TP in the sediment, but has no significant effect on the changes of insoluble P and Ca - P.

[0041] Those skilled in the art should understand that the present invention is not limited by the above - mentioned embodiments. What is described in the above - mentioned embodiments and the specification is only to illustrate the principle of the present invention. Without departing from the spirit and scope of the present invention, the present invention will have various changes and improvements, and these changes and improvements all fall within the scope of the present invention claimed. The scope of protection claimed by the present invention is defined by the appended claims and their equivalents.

Claims

1. Experimental device for the influence of irrigation return flow on the material transfer at the sediment-water interface, characterized in that: It includes a test chamber, a partition chamber and a partition net plate; The test chamber is a cuboid-shaped transparent structure with an open top. The two side faces of the test chamber in the length direction are the water inlet surface and the water outlet surface respectively. A baffle is arranged parallel to the water outlet surface near the water outlet surface in the test chamber, and a first groundwater chamber is formed between the right side of the baffle and the water outlet surface of the test chamber; The partition chamber is cuboid-shaped and covers the test chamber with a closed top. A partition is arranged vertically in the partition chamber to divide the partition chamber into a left chamber and a second groundwater chamber. A first test chamber is formed between the left side of the left chamber and the water inlet surface of the test chamber, and a second test chamber is formed between the right side of the second groundwater chamber and the baffle of the test chamber; The partition net plate includes a first partition net plate and a second partition net plate. The first partition net plate is horizontally arranged in the first test chamber, and the circumference of the first partition net plate is respectively connected to the inner wall of the test chamber and the outer wall of the left chamber. The second partition net plate is horizontally arranged in the second test chamber, and the circumference of the second partition net plate is respectively connected to the outer wall of the second groundwater chamber, the inner wall of the test chamber and the baffle. A pore group communicating with the second test chamber is arranged on the part of the right side wall of the second groundwater chamber below the second partition net plate, and a pore group connecting the second test chamber with the first groundwater chamber is arranged on the part of the baffle below the second partition net plate; An overlying water inlet is arranged on the water inlet surface of the test chamber above the first partition net plate and near the top of the test chamber, and a groundwater inlet is arranged on the water inlet surface of the test chamber below the first partition net plate. A groundwater outlet is arranged on the water outlet surface of the test chamber below the second partition plate; A groundwater conduction port is arranged on each of the left and right chamber walls of the left chamber on the partition chamber, and the groundwater conduction port is located below the first partition net plate. The groundwater conduction ports on the partition chamber are connected by a hose; 2. The experimental device for studying the influence of irrigation return flow on the migration of substances at the sediment-water interface according to claim 1, characterized in that: The height of the partition chamber is lower than the height of the test chamber, and the height of the baffle is equal to the height of the water outlet surface of the test chamber; 3. The experimental device for studying the influence of irrigation return flow on the migration of substances at the sediment-water interface according to claim 1, characterized in that: Sediments are arranged on the second partition net plate; 4. The test device for the influence of irrigation return flow on the migration of substances at the sediment-water interface according to claim 1, characterized in that: Saline soil is arranged on the first partition net plate, and sediments are arranged on the second partition net plate; 5. A test method for the impact of irrigation return flow on the migration of substances at the sediment-water interface of the test device for the impact of irrigation return flow on the migration of substances at the sediment-water interface according to any one of claims 1-4, characterized in that: The specific test method is as follows: S1: Static test: Select sediments to be laid on the second partition net plate, and the thickness of the sediments is 4 - 5 cm. Disconnect the hose in the left chamber, add overlying water to the second test chamber, and the thickness of the overlying water is 20 - 25 cm and does not exceed the height of the partition chamber. The test lasts for ten days, and samples are taken at the same time every day. The water sample is taken at a position 5 - 10 cm above the sediment interface, and 12 ml is extracted each time, and the total phosphorus content and the dissolved inorganic phosphorus content are measured. The sediment sample is taken from the sediment 1 cm below the sediment interface, and 1 - 2 g is taken each time for the measurement and analysis of phosphorus forms; S2: Dynamic test: Select sediment to be laid on the second partition grid plate with a thickness of 4 - 5 cm; select saline soil to be laid on the first partition grid plate with a thickness of 10 - 15 cm; connect the hose in the left chamber; inject overlying water into the first laboratory through the overlying water inlet, with the overlying water 20 - 25 cm above the saline soil interface, and the overlying water flowing over the partition into the second laboratory, making the water surface higher than the partition; inject groundwater into the first laboratory through the groundwater inlet, and the groundwater flows into the second groundwater chamber through the hose, then into the second laboratory through the pore group, then into the first groundwater chamber through the pore group, and finally discharged through the groundwater outlet; the test lasts for ten days, with a sample taken at the same time every day, and the water sample is taken at a point 5 - 10 cm above the sediment interface, 12 ml is taken each time, and the total phosphorus content and the dissolved inorganic phosphorus content are measured; the sediment sample is taken from the sediment 1 cm below the sediment interface, 1 - 2 g is taken each time, for the measurement and analysis of phosphorus forms.

Images