A method for emergency elimination of algal blooms

Abstract

The present invention discloses a method for emergently eliminating algal blooms, which comprises the following steps: pre-laying an aeration device in a river channel, with the aeration position at a certain height from the river bottom, turning on the aeration to increase the dissolved oxygen value of the water body to a certain value, spraying a clay mixture into the river channel after turning off the aeration, testing and plotting a clay adsorption characteristic curve to obtain the time node when the fastest clay adsorption rate stage ends, turning on the aeration device to increase the dissolved oxygen of the water body to a certain value, turning off the aeration again to obtain the time node when the clay adsorption curve reaches equilibrium, turning on the aeration device to increase the dissolved oxygen of the water body to a certain value again, and turning off the aeration, testing and plotting a clay sedimentation characteristic curve to obtain the time node when 80% of the clay particle sedimentation height is below the height of the aeration pipe, and finally turning on the aeration to restore the dissolved oxygen value of the water body, completing the effect of aeration-assisted clay in eliminating algal blooms.

Description

Technical Field

[0001] The present invention relates to the technical field of algal bloom control in water environment, and particularly relates to a method for emergently eliminating algal blooms. Background Art

[0002] Algal bloom is a water environment disaster phenomenon of explosive growth of water - body algae, which is likely to occur in lakes, reservoirs, rivers and near - seas with relatively high temperatures and eutrophication. The explosive algal population in algal blooms can float, drift and aggregate when meteorological and hydrological conditions are suitable, and it is extremely easy to gather into a layer of blue - green and fishy - smelling floating foam on the water surface, so it is also called cyanobacterial bloom. The harms it brings are mainly manifested as follows: blocking the exchange of air and gases in water, and after the death of algae, the decomposition consumes oxygen in the water body, causing the dissolved oxygen concentration in the water body to rapidly decrease, resulting in a large number of aquatic animals suffocating to death due to lack of oxygen; blocking sunlight and affecting the photosynthesis of submerged plants; seriously affecting the survival of aquatic organisms, destroying the ecological balance of the water environment, leading to changes in the structure and degradation of the function of the lake ecosystem, and ultimately resulting in the collapse of the entire water - body ecosystem; releasing algal toxins, and the toxins accumulate and are transmitted in the food chain, endangering the health of humans and other animals; at the same time, seriously affecting the water area landscape, releasing peculiar smells and affecting the living environment of residents around the water area.

[0003] At present, the emergency treatment measures for algal blooms mainly include chemical agent spraying, mechanical salvage, clay method treatment, etc. Among them, the use of chemical agents such as aluminum salts and iron salts in chemical agent spraying is gradually prohibited due to reasons such as secondary pollution; when facing large - area cyanobacterial blooms, the salvage volume of mechanical salvage is limited and time - consuming and labor - intensive; the clay method treatment was first applied to the treatment of red tides in the near - sea. Because it uses natural mineral soil with rich sources, low cost and no secondary pollution problems, it is considered to be one of the potential and powerful measures for algal bloom control. This technology requires a large amount of spraying in actual application. The conventional technical route is to modify natural mineral soil to improve its performance and reduce the usage amount. The modification measures mainly focus on chemical agent modification, which has potential problems of increased cost and secondary pollution. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for emergently eliminating algal blooms, which is used to solve the problems of secondary pollution and limited treatment effect existing in the treatment of algal blooms by using modified clay in the prior art. The method for emergently eliminating algal blooms of the present invention belongs to an application mode of the method of eliminating algal blooms by aeration - assisted clay.

[0005] The purpose of the present invention can be realized by the following technical solutions:

[0006] A method for emergently eliminating algal blooms, comprising the following steps:

[0007] S1. Test and plot the clay adsorption characteristic curve to obtain the first time node at the end of the fastest clay adsorption rate stage and the second time node when the clay adsorption curve reaches equilibrium.

[0008] S2. Test and plot the clay sedimentation characteristic curve to obtain the third time node when the sedimentation height of 80% of the clay particles is below the height of the aeration pipe.

[0009] S3. Install the submerged aeration device in the treatment river channel in zones. The aeration pipe included in the submerged aeration device is arranged below the liquid level and above the riverbed, with a height of 40 cm - 80 cm from the riverbed.

[0010] S4. After the aeration pipe is installed, start aeration to increase the dissolved oxygen concentration in the water body to 3 - 5 mg / L.

[0011] S5. Uniformly spray the clay mixture into the water body, and the spraying amount of the clay mixture is 4 - 400 tons per square kilometer.

[0012] S6. Start timing after spraying the clay mixture. Start aeration according to the first and second time nodes obtained in step S1. The end time of each aeration is terminated when the dissolved oxygen in the water body increases by 1 - 2 mg / L, and start aeration according to the third time node obtained in step S2. The end time of each aeration is terminated when the dissolved oxygen in the water body reaches not less than 5 mg / L.

[0013] S7. One day after the aeration ends, remove the aeration device from the river channel to complete the aeration-assisted clay treatment of algal blooms operation.

[0014] As a further solution of the present invention: In step S3, the aeration device further includes an air delivery pipe, an anchoring rope, and an anchoring block. During the installation process of the aeration pipe, the anchoring block is fixed on the riverbed. The anchoring block is connected to the aeration pipe through the anchoring rope, and the air inlet end of the aeration pipe is connected to the air delivery pipe, and the aeration pipe is laid along the river water flow direction.

[0015] As a further solution of the present invention: In step S3, the height of the aeration pipe from the riverbed is adjusted by the length of the anchoring rope.

[0016] As a further solution of the present invention: In step S6, when the third time node is close to the second time node, with a difference within 15 minutes or the third time node is shorter than the second time node, then the second time node is used as the final start aeration time, and the end time of aeration is terminated when the dissolved oxygen in the water body reaches not less than 5 mg / L.

[0017] As a further solution of the present invention: In step S4, if the dissolved oxygen concentration in the water body is not lower than 3 mg / L before starting aeration, then there is no need to start aeration.

[0018] As a further solution of the present invention: In step S5, the clay mixture is sprayed according to the aeration zones, and is sprayed from the upstream to the downstream, and the spraying time for each zone is controlled within 5 - 10 minutes.

[0019] As a further solution of the present invention: The clay material of the clay mixture in step S5 meets the requirements of the red tide elimination materials and methods in the "Technical Guidelines for Red Tide Disaster Treatment (GBT 30743 - 2014)".

[0020] As a further solution of the present invention: The clay material of the clay mixture in step S5 is natural clay, and the natural clay is finely pulverized, and the particle size of the pulverized clay particles is equal to or close to the size of the algal bloom organisms' cells. Among them, the ratio of clay to water in the clay mixture is 1∶50 - 1∶200.

[0021] Advantages of the present invention:

[0022] (1) By controlling the key nodes of the clay in different flow states in the water body, aeration is assisted at three time nodes. The aeration stirs the clay to adsorb, aggregate, and restrict the algae in the water, and gradually precipitates under the action of gravity, reducing the concentration of the algal bloom by 2 - 3 orders of magnitude. After the last aeration time node, the dissolved oxygen in the water body can be quickly restored, and at the same time, the environment where the algae aggregate on the water surface in a mild environment is destroyed, significantly improving the water quality and sensory effects;

[0023] (2) By adopting this method for precise control, combining the natural characteristics, adsorption characteristics, and hydrodynamic sedimentation characteristics of the clay, the effect of the clay in use is maximized, and the potential high cost and secondary pollution problems in the clay modification for treating algal blooms can be effectively avoided;

[0024] (3) By adopting this method, not only the emergency operation during the outbreak of the algal bloom in the river is effectively realized, but also the operation requirements for quickly restoring the original state of the river after treatment are met. Description of the Drawings

[0025] The present invention will be further described below with reference to the drawings.

[0026] Figure 1 It is a schematic diagram of the laying of the aeration device of the present invention;

[0027] Figure 2 It is a schematic diagram of the clay adsorption characteristic curve of the present invention;

[0028] Figure 3 It is a schematic diagram of the clay sedimentation characteristic curve of the present invention.

[0029] In the figure: 1, liquid level; 2, riverbed; 3, gas transmission pipe; 4, aeration pipe; 5, anchor rope; 6, anchor block. Detailed Embodiments

[0030] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. 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 protection scope of the present invention.

[0031] In the description of the present invention, it should be understood that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as a limitation to the present invention; in the description of the present invention, the meanings of "a plurality" and "several" are at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0032] Please refer to Figures 1-3 As shown, the present invention is a method for emergently eliminating algal blooms, including the following steps:

[0033] S1. Test and draw a clay adsorption characteristic curve graph to obtain the first time node when the fastest clay adsorption rate stage ends, and obtain the second time node when the clay adsorption curve reaches equilibrium.

[0034] S2. Test and draw a clay sedimentation characteristic curve graph to obtain the third time node when the sedimentation height of 80% of the clay particles is below the height of the aeration pipe 4.

[0035] S3. Install a submerged aeration device in a partitioned manner in the treatment river channel. The aeration pipe 4 included in the submerged aeration device is arranged below the liquid surface 1 and above the riverbed 2, and has a height of 40 cm - 80 cm from the riverbed 2.

[0036] In this step, it is necessary to install a submerged aeration device in a partitioned manner in the river channel for auxiliary use. The submerged aeration device further includes an air delivery pipe 3, an anchoring rope 5, and an anchoring block 6. During the installation process of the aeration pipe 4, the anchoring block 6 is fixed on the riverbed 2, the anchoring block 6 is connected to the aeration pipe 4 through the anchoring rope 5, and the air inlet end of the aeration pipe 4 is connected to the air delivery pipe 3, and the aeration pipe 4 is laid along the river water flow direction, so that both installation and removal are convenient, and it is convenient to install and use in case of an emergency of algal bloom outbreak.

[0037] Moreover, the height of the aeration pipe 4 installed and arranged in this step from the riverbed 2 is adjusted by the length of the anchor rope 5. The height of the aeration pipe 4 from the riverbed 2 is 40 cm - 80 cm, which is convenient for floating adjustment. Among them, the height of the aeration pipe 4 from the riverbed 2 at 40 cm is the lower limit value, which can avoid aeration stirring the bottom mud and causing "lake blooming". The height of the aeration pipe 4 from the riverbed 2 at 80 cm is the floating upper limit value. However, when the water depth exceeds 1.6 m, the floating upper limit value of the height of the aeration pipe 4 from the riverbed 2 at 80 cm can be increased. The floating increase value is 1 / 5 - 1 / 4 of the depth value exceeding 1.6 m. When the height of the aeration pipe 4 from the riverbed 2 is different, according to the clay settlement characteristics in S2, the time node three when 80% of the clay particles settle below the height of the aeration pipe 4 is different.

[0038] S4. After the aeration pipe 4 is arranged, start aeration to increase the dissolved oxygen concentration in the water body to 3 - 5 mg / L. The initial aeration can improve the dissolved oxygen activity in the water body. However, when the dissolved oxygen concentration in the water body is not less than 3 mg / L, there is no need to start aeration, and aeration can be directly carried out at time node one, time node two, and time node three.

[0039] S5. Uniformly spray the clay mixture into the water body. The spraying amount of the soil mixture is 4 - 400 tons per square kilometer. The clay mixture is sprayed according to the aeration zone and is sprayed from the upstream to the downstream. The spraying time for each zone is controlled within 5 - 10 minutes. The clay material of the clay mixture meets the requirements of the red tide elimination materials and methods in the "Technical Guidelines for Red Tide Disaster Treatment GBT30743 - 2014".

[0040] In this step, the clay material of the clay mixture uses natural clay. The natural clay is finely pulverized, and the particle size of the pulverized clay particles is equal to or close to the algal bloom biological cells. Among them, the ratio of clay to water in the clay mixture is 1∶50 - 1∶200, and the ratio of the clay mixture can be selected according to factors such as the actual condition of the water body.

[0041] S6. Start timing after spraying the clay mixture. Start aeration according to time node one and time node two obtained in step S1. The end time of each aeration is terminated when the dissolved oxygen in the water body increases by 1 - 2 mg / L. And start aeration according to time node three obtained in step S2. The end time of each aeration is terminated when the dissolved oxygen in the water body reaches not less than 5 mg / L.

[0042] In this step, the installation height of the aeration pipe 4 in step S3 is different, and the time node three when 80% of the clay particles settle below the height of the aeration pipe 4 is different. When time node three is close to time node two, the difference in time is within 15 minutes or time node three is shorter than time node two, then time node two is taken as the final start aeration time, and the end time of aeration is terminated when the dissolved oxygen in the water body reaches not less than 5 mg / L.

[0043] One day after the aeration ends, remove the aeration device from the river channel to complete the operation of using aeration-assisted clay to control algal blooms.

[0044] In this method, the aeration device is pre-laid in the river channel at a certain height from the river bottom. Start aeration to increase the dissolved oxygen value in the water body to a certain value. After turning off the aeration, spray the clay mixture into the river channel. According to the test and draw the clay adsorption characteristic curve to obtain the time node when the fastest clay adsorption rate stage ends - turn on the aeration device, increase the dissolved oxygen in the water body to a certain value, and then turn off the aeration again to obtain the time node when the clay adsorption curve reaches equilibrium - turn on the aeration device, increase the dissolved oxygen in the water body to a certain value again, and then turn off the aeration. According to the test and draw the clay sedimentation characteristic curve to obtain the time node when 80% of the clay particle sedimentation height is below the height of the aeration pipe 4. Finally, turn on the aeration to restore the dissolved oxygen value of the water body. After completing the above steps, remove the aeration device from the river channel to complete the effect of using aeration-assisted clay to eliminate algal blooms.

[0045] In this specific embodiment, when this method is used for the implementation operation of using natural clay to control algal blooms, such as Figure 1 shown, test and draw the adsorption characteristic curve of natural clay. The time node when the fastest clay adsorption rate stage ends is 5 minutes, and the time node when the clay adsorption curve reaches equilibrium is 50 minutes. As Figure 2 shown, test and draw the sedimentation characteristic curve of natural clay. The height of the aeration pipe 4 from the river bed 2 is 40 cm, and the time node when 80% of the clay particle sedimentation height is below the height of the aeration pipe 4 is 82 minutes. As Figure 3 shown, the aeration device is arranged in the river channel. When the dissolved oxygen concentration in the water body is lower than 3 mg / L, turn on the aeration to increase the dissolved oxygen concentration in the water body to 3 - 5 mg / L, then turn off the aeration, and evenly spray the clay mixture into the water body. Start timing after spraying the clay mixture. When the time after spraying reaches the time node of 5 minutes (the first time node), turn on the aeration and terminate the aeration when the dissolved oxygen in the water body increases by 1 - 2 mg / L. When the time after spraying reaches the time node of 50 minutes (the second time node), turn on the aeration and terminate the aeration when the dissolved oxygen in the water body increases by 1 - 2 mg / L. When the time after spraying reaches the time node of 82 minutes (the third time node), turn on the aeration and terminate the aeration when the dissolved oxygen in the water body reaches not less than 5 mg / L. According to the clay adsorption and sedimentation characteristics, assist aeration at the three time nodes. The aeration stirs the clay to adsorb, aggregate, and restrict the algae in the water, and gradually precipitate under the action of gravity, reducing the algal bloom concentration by 2 - 3 orders of magnitude. After the last aeration time node, the dissolved oxygen in the water body can be quickly restored, and at the same time, the environment where algae gather on the water surface in a mild environment is destroyed. One day after the aeration ends, remove the aeration device from the river channel to complete the operation of using aeration-assisted clay to control algal blooms.

[0046] It should be understood that the clay for controlling algal blooms can also be modified clay. The adsorption characteristics and sedimentation characteristics of the modified clay are also tested and a curve graph is drawn to obtain Time Node 1, Time Node 2, and Time Node 3. According to the installation height of the aeration pipe 4 from the riverbed 2, auxiliary aeration is carried out at the three time nodes respectively to increase the dissolved oxygen concentration in the water body, so as to quickly improve the effect of controlling algal blooms.

[0047] The above has described an embodiment of the present invention in detail, but the content described is only the preferred embodiment of the present invention and cannot be considered as limiting the scope of implementation of the present invention. All equivalent changes and improvements made according to the scope of the application of the present invention should still fall within the scope covered by the patent of the present invention.

Claims

1. A method for emergency elimination of algal blooms, characterized in that, It includes the following steps: S1. Test and draw a clay adsorption characteristic curve to obtain the first time node at the end of the stage with the fastest clay adsorption rate, and obtain the second time node when the clay adsorption curve reaches equilibrium; S2. Test and draw a clay sedimentation characteristic curve to obtain the third time node when the sedimentation height of 80% of the clay particles is below the height of the aeration pipe (4); S3. Install a submerged aeration device in the treatment river channel in a partitioned manner. The aeration pipe (4) of the submerged aeration device is arranged below the liquid surface (1) and above the riverbed (2), with a height of 40 cm - 80 cm from the riverbed (2); S4. After the aeration pipe (4) is installed, start aeration to increase the dissolved oxygen concentration in the water body to 3 - 5 mg / L; S5. Uniformly spray a clay mixture into the water body, and the spraying amount of the clay mixture is 4 - 400 tons per square kilometer; S6. Start timing after spraying the clay mixture. Start aeration according to the first time node and the second time node obtained in step S1. The end time of each aeration is terminated when the dissolved oxygen in the water body increases by 1 - 2 mg / L, and start aeration according to the third time node obtained in step S2. The end time of each aeration is terminated when the dissolved oxygen in the water body reaches not less than 5 mg / L; S7. One day after the aeration ends, remove the aeration device from the river channel to complete the aeration-assisted clay treatment of algal blooms operation.

2. The method for emergency elimination of algal blooms according to claim 1, characterized in that, In step S3, the submerged aeration device further includes: an air delivery pipe (3), an anchoring rope (5) and an anchoring block (6). During the installation process of the aeration pipe (4), the anchoring block (6) is fixed on the riverbed (2), the anchoring block (6) is connected to the aeration pipe (4) through the anchoring rope (5), and the air inlet end of the aeration pipe (4) is connected to the air delivery pipe (3), and the aeration pipe (4) is laid along the river water flow direction.

3. The method for emergently eliminating algal blooms according to claim 2, wherein In step S3, the height of the aeration pipe (4) from the riverbed (2) is adjusted by the length of the anchoring rope (5).

4. A method for emergency elimination of algal blooms according to claim 3, characterized in that, In step S6, when the third time node is close to the second time node, with a difference of within 15 minutes or the third time node is shorter than the second time node, then the second time node is taken as the final start aeration time, and the end time of aeration is terminated when the dissolved oxygen in the water body reaches not less than 5 mg / L.

5. The method for emergency elimination of algal blooms according to claim 1, characterized in that, In step S4, if the dissolved oxygen concentration in the water body is not less than 3 mg / L before starting aeration, then there is no need to start aeration.

6. The method for emergency elimination of algal blooms according to claim 1, characterized in that, In step S5, the clay mixture is sprayed in accordance with the aeration partitions and is sprayed from the upstream to the downstream, and the partition spraying time is controlled within 5 - 10 minutes.

7. A method for emergently eliminating algal blooms according to claim 1, characterized in that, In step S5, the clay material of the clay mixture uses natural clay, and the natural clay is finely pulverized. The particle size of the pulverized clay particles is equal to or close to the algal bloom biological cells. Among them, the ratio of clay to water in the clay mixture is 1∶50 - 1∶200.

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