Novel combined treatment method for cyanobacteria bloom

Abstract

To provide a novel combined treatment method for cyanobacteria bloom, which relates to a technical field of an environmental management.SOLUTION: A combined treatment method of the present invention includes: (1) an agglomeration step of calculating a volume of a water body, adding polyaluminum chloride powder in the amount of 5 to 10 ppm, mixing thoroughly with water before adding the polyaluminum chloride powder to completely dissolve the powder, and spraying evenly along a water surface; (2) a stirring step of moving a boat back and forth across the water surface to uniformly mix the added polyaluminum chloride with lake water; and (3) a sonication step of, after leaving the same for a certain period of time, performing ultrasonic treatment by moving back and forth across a surface of the water body using a mobile ultrasonic treatment device. The present invention can quickly remove cyanobacterial cells and maintain a control effect for a longer period, thereby achieving a purpose of treating dispersed cyanobacterial blooms.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to the technical field of environmental management, and in particular to a combined treatment method for novel cyanobacterial blooms. [Background technology]

[0002] Cyanobacterial blooms are a serious environmental problem facing current aquatic ecosystems. Their cause is the proliferation of cyanobacteria, such as Microcystis, Dolichospermum, and Aphanizomenon, in water bodies. Under suitable environmental conditions, they rise to the surface, concentrate, and form a paint-like cyanobacterial oil film. The occurrence of cyanobacterial blooms not only affects the appearance of the water body, but also causes hypoxia in the water, threatening the growth of other aquatic plants and animals and causing the mass death of other aquatic organisms, further reducing the water body's oxygen content and creating a vicious cycle. Furthermore, some cyanobacterial strains also produce cyanotoxins or odorous compounds, directly threatening the water safety of surrounding residents.

[0003] Currently, most common cyanobacterial blooms are concentrated blooms, meaning that algae cells are mainly concentrated on the surface of the water body and form groups. Ultrasonic devices are currently common for treating concentrated cyanobacterial blooms, but in recent years, the occurrence frequency and area of ​​a new type of cyanobacterial bloom, Raphidiopsis bloom, has become more widespread. There are few reports on the use of current ultrasonic algaecide devices to treat new type of cyanobacterial blooms.

[0004] At present, there is more mature technology for treating concentrated cyanobacterial blooms, but there is still a lack of relevant domestic and international treatment technology for distributed cyanobacterial blooms formed by the new type of bloom cyanobacterium, Raphidiopsis.

[0005] Currently, similar cyanobacteria treatment technologies are characterized primarily as follows. Treatment methods are primarily divided into physical, chemical, and biological methods. Physical methods include (1) using mechanical salvage to remove cyanobacteria cells from water bodies; (2) adding flocculants to alter the surface charge of algae cells (groups), causing them to aggregate into larger particles and gradually sink to the bottom; and (3) using pressure or spraying to break the air pockets in the algae cells, changing their density and causing them to sink to the bottom. Chemical methods primarily use strong oxidizing agents, such as hydrogen peroxide, sodium hypochlorite, and ozone, to oxidize and kill algae cells, achieving the goal of eliminating blooms. Biological methods primarily use microbial agents with added algicidal properties to directly kill or inhibit the activity of algae cells through the algae-inhibiting effects of microorganisms, achieving the goal of eliminating blooms. For example, Patent Document 1 describes a mixed coagulant in which tertiary sepiolite fluff, talc, and diatomaceous earth are mixed in a ratio of 1-4:3-12:2-8, and a method for controlling blue-green algae blooms using the same.

[0006] While the above techniques are effective in treating concentrated cyanobacterial blooms, they are less effective in treating dispersed cyanobacterial blooms. The main problems are as follows: (1) Mechanical salvage is expensive, the process is complicated, requires investment in specialized technicians and equipment, and is likely to affect the growth of fish and other aquatic plants and animals. Furthermore, in the case of new dispersed cyanobacterial blooms, algae cells are not concentrated on the surface of the water body, so mechanical salvage is inefficient and cannot salvage the algae. (2) Techniques such as pressurization and spraying also require specialized equipment and skills, which are expensive. Unlike concentrated algal blooms, which can collect high-abundance algae cells concentrated on the surface, dispersed cyanobacterial blooms have algae cells that are uniformly distributed throughout the water, resulting in low collection efficiency and low pressurization or spraying efficiency. (3) Chemical agents pose safety risks, potentially affecting the growth of fish and other aquatic plants and animals. Residual agents are also prone to secondary pollution. Because algae cells tend to disperse too much, the amount of chemical agent added is much higher than for concentrated blooms, resulting in higher costs. (4) Microbial agents have a longer effective lifespan, typically requiring several weeks or even months to achieve the desired effect. Most have specific requirements for the aquatic environment, requiring adjustments to the type and dosage of agents used. Furthermore, as an invasive species, their addition to aquatic environments may pose certain ecological risks. (5) The use of blocking agents is a new, dispersed cyanobacterial bloom removal method that can effectively remove algae cells in the water column, but typically only lasts for a week and is prone to rebound. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Chinese Patent Application Publication No. 110642472A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to solve the problems of the prior art by providing a new combined treatment method for cyanobacterial blooms, which can quickly remove cyanobacterial cells and maintain the control effect for a longer period of time, thereby achieving the purpose of treating dispersed cyanobacterial blooms. [Means for solving the problem]

[0009] To achieve the above object, the present invention provides the following solutions: The present invention provides a novel method for combined treatment of cyanobacterial blooms, Calculate the volume of the water body, add polyaluminum chloride powder in an amount of 5-10 ppm, and before adding the polyaluminum chloride powder, mix it thoroughly with water to completely dissolve the powder, and then spray it evenly along the water surface. (1) Agglomeration step. A stirring step (2) in which the boat is moved back and forth across the water surface to uniformly mix the added polyaluminum chloride with the lake water; After leaving the solution to stand for a certain period of time, an ultrasonic treatment step (3) is carried out using a mobile ultrasonic treatment device that moves back and forth across the surface of the body of water to perform ultrasonic treatment.

[0010] Preferably, when the volume of the water body is within 700,000 cubic meters, at least one mobile ultrasonic treatment device is used for treatment every day, and the daily treatment time is 6 hours or more. When the volume of the water in the treatment area is greater than 700,000 cubic meters, at least one mobile ultrasonic treatment device is added for each additional 700,000 cubic meters to simultaneously perform ultrasonic treatment.

[0011] Preferably, the mobile ultrasonic processing device includes a hull, an ultrasonic vibration plate, and an ultrasonic control system, and a plurality of ultrasonic vibration plates are installed on both sides of the hull, each ultrasonic vibration plate is electrically connected to the ultrasonic control system, and the ultrasonic control system is installed on the hull.

[0012] Preferably, each of the ultrasonic vibration plates is mounted on a vibration plate bracket, and each of the vibration plate brackets is fixedly attached to the side of the hull.

[0013] Preferably, three ultrasonic vibration plates are installed on each side of the hull, and the ultrasonic vibration plates on both sides are installed symmetrically with respect to the hull.

[0014] Preferably, the rated power of the ultrasonic vibration plate is 2.1 kw and the ultrasonic frequency is 28 kHz.

[0015] Preferably, the hull is fitted with a marine battery or gasoline / diesel generator for providing electrical energy to the ultrasonic vibrating plate and the ultrasonic control system.

[0016] Preferably, the diaphragm bracket is a stainless steel bracket. [Effects of the Invention]

[0017] Compared with the prior art, the present invention achieves the following technical advantages:

[0018] The combined treatment method for new-type cyanobacterial blooms provided by the present invention involves adding a certain concentration of a blocking agent to rapidly aggregate and settle the new-type bloom cyanobacterial cells within a short period of time, and then using a mobile ultrasonic device to suppress the activity of residual algae cells in the water column. This combined technology can quickly remove cyanobacterial cells and maintain the control effect for a longer period of time, thereby achieving the purpose of treating dispersed cyanobacterial blooms. [Brief explanation of the drawings]

[0019] In order to more clearly describe the embodiments of the present invention or the technical solutions in the prior art, the following will briefly describe the drawings that need to be used in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention, and those skilled in the art can further obtain other drawings based on these drawings without any creative efforts.

[0020] [Figure 1] 1 is a three-dimensional structural schematic diagram of a side front view of a mobile ultrasound processing device according to the present invention. [Figure 2] 1 is a three-dimensional structural schematic diagram of a side and rear view of a mobile ultrasonic processing device according to the present invention. [Figure 3] 1 is a three-dimensional structural schematic diagram of a front view of a mobile ultrasonic processing device according to the present invention. [Figure 4] This is a graph showing the effect of a controlled experiment in which pure cultured algae strains were treated with PAC indoors. [Figure 5] 1 shows the effect of treating wild Cylindrospermopsis raciborskii with PAC. [Figure 6] This is a graph showing the effect of treating Cylindrospermopsis raciborskii water samples with different concentrations of PAC over time. [Figure 7] 1 is a graph showing the effect of treating a lake by adding PAC alone and by combining PAC and ultrasound. DETAILED DESCRIPTION OF THE INVENTION

[0021] The following provides a clear and complete description of the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some of the embodiments of the present invention, and not all of the embodiments, and all other embodiments obtained by those skilled in the art without any creative efforts based on the embodiments of the present invention are all within the scope of protection of the present invention.

[0022] The present invention aims to solve the problems existing in the prior art and provide a new combined treatment method for cyanobacterial blooms, which can quickly remove cyanobacterial cells and maintain the control effect for a longer period of time, thereby achieving the purpose of treating dispersed cyanobacterial blooms. [Example]

[0023] In order to make the above objects, features and advantages of the present invention more apparent and comprehensible, the present invention will be described in more detail below with reference to the drawings and detailed description of the invention.

[0024] As shown in FIGS. 1 to 3, this embodiment Calculate the volume of the water body, calculate the volume of the water body from the area and depth of the water body, add polyaluminum chloride powder in an amount of 5 to 10 ppm, and before adding the polyaluminum chloride powder, mix it thoroughly with water to completely dissolve the powder, and then spray it evenly along the water surface. (1) Agglomeration step; (2) agitation step in which the boat is moved back and forth across the water surface to mix the added polyaluminum chloride with the lake water uniformly, and the boat stirring time needs to be increased, especially in areas with a lot of foam on the surface of the water body; and (3) an ultrasonic treatment step in which, after leaving the solution to stand for 6 hours, the solution is ultrasonicated using a mobile ultrasonic treatment device that moves back and forth across the surface of the body of water.

[0025] In this method, the addition of a certain concentration of blocking agent can rapidly aggregate and settle the new type of bloom cyanobacterial cells within a short period of time, and then a mobile ultrasonic device is used to suppress the activity of residual algae cells in the water column. This combined technology can quickly remove cyanobacterial cells and maintain the control effect for a longer period of time, achieving the purpose of treating dispersed cyanobacterial blooms.

[0026] Here, if the volume of the water body is within 700,000 cubic meters, at least one mobile ultrasonic treatment device should be used for treatment every day, with the daily treatment time being 6 hours or more. If the volume of the water in the treatment area is greater than 700,000 cubic meters, at least one additional mobile ultrasonic treatment device should be added for each additional 700,000 cubic meters to perform ultrasonic treatment simultaneously.

[0027] In this embodiment, the mobile ultrasonic treatment device includes a hull 1, an ultrasonic vibration plate 2, and an ultrasonic control system 3, with multiple ultrasonic vibration plates 2 installed on both sides of the hull 1, each ultrasonic vibration plate 2 electrically connected to an ultrasonic control system 3, which is installed on the hull 1. The mobile ultrasonic treatment device is easy to use and flexible, and the ultrasonic vibration plate 2 is a rectangular plate, allowing a large area to be treated at the same time, improving treatment efficiency.

[0028] In this embodiment, each ultrasonic vibration plate 2 is installed on a vibration plate bracket 4, and each vibration plate bracket 4 is fixedly attached to the side of the hull 1. The vibration plate bracket 4 is a stainless steel bracket, and installing the ultrasonic vibration plate 2 via the vibration plate bracket 4 makes installation convenient.

[0029] In this embodiment, three ultrasonic vibration plates 2 are installed on each side of the hull 1, and the ultrasonic vibration plates 2 on both sides are installed symmetrically with respect to the hull 1.

[0030] In this embodiment, the rated power of the ultrasonic vibration plate 2 is 2.1 kw, and the ultrasonic frequency is 28 kHz.

[0031] In this embodiment, a marine battery or a gasoline / diesel generator is installed on the hull 1 to provide electrical energy to the ultrasonic vibration plate 2 and the ultrasonic control system 3 .

[0032] The mobile ultrasonic treatment device can be used when the algae cell density is less than 1 billion cells per liter, and below this threshold, the efficiency of the device can be increased.

[0033] The following is an experiment employing polyaluminum chloride (PAC) to treat Cylindrospermopsis raciborskii.

[0034] As shown in Figure 4, in a controlled experiment on pure culture algae strains indoors, the effect of treating Cylindrospermopsis raciborskii with PAC (treatment effect of pure algae): When 10 mg / L PAC was added, the optical density at 680 nm (OD680) and chlorophyll a concentration (Chl-a) of pure algae, Cylindrospermopsis raciborskii, were all significantly lower than those of the control group (PAC concentration 0 mg / L). As the PAC concentration increased (from 10 mg / L to 40 mg / L), the decreasing trend became more pronounced, indicating that PAC had a significant removal effect on Cylindrospermopsis raciborskii.

[0035] As shown in Figure 5, the effect of treating wild Cylindrospermopsis raciborskii with PAC: wild Cylindrospermopsis raciborskii bloom samples (initial density 10 12 When 10mg / L PAC was added to a medium containing 1000mg / L of urea (high concentration of 1000mg / L), the cell density of Cylindrospermopsis raciborskii decreased significantly and the removal rate was as high as 60%. As the PAC concentration increased to 40mg / L, the cell removal rate of Cylindrospermopsis raciborskii gradually increased to over 80%, indicating that PAC has a significant removal effect on Cylindrospermopsis raciborskii.

[0036] As shown in Figure 6, when testing the effect of PAC on Cylindrospermopsis raciborskii, after 30 minutes of treatment, 10 mg / L PAC significantly reduced the chlorophyll a concentration in the water samples of Cylindrospermopsis raciborskii. The number of viable cells of Cylindrospermopsis raciborskii significantly decreased. As the PAC concentration increased up to 40 mg / L, the chlorophyll a concentration of Cylindrospermopsis raciborskii decreased significantly. At the same time, when the treatment time was extended to 60 minutes, the chlorophyll a concentration of Cylindrospermopsis raciborskii in each treatment group decreased more significantly. Treating Cylindrospermopsis raciborskii cells with 10 mg / L PAC for 30 minutes significantly killed the algae cells. This indicates that increasing the PAC concentration or treatment time can improve the treatment effect.

[0037] The combined PAC and ultrasound technology was successfully applied to a city lake, effectively eliminating a Cylindrospermopsis raciborskii bloom during a two-month experiment. The lake had a water volume of approximately 700,000 cubic meters. Approximately 7 tons of PAC was added during each flocculation experiment. As shown in Figure 7, the solid dots indicate the time of PAC addition. In the previous experiment, PAC was added without ultrasound. The results show that after PAC addition, the cell density of Cylindrospermopsis raciborskii decreased significantly, but then rebounded within about 10 days, returning to pre-treatment levels and even slightly increasing. In a later experiment, after adding 7 tons of PAC, an ultrasonic device was used to continuously operate the device for 6 hours every day. Over the course of the following month, the removal of Cylindrospermopsis raciborskii was significant, and the algae density was maintained at a consistently low level, demonstrating a high bloom treatment effect. [Industrial Applicability]

[0038] The present invention uses specific examples to explain the principles and embodiments of the present invention, and the above examples are only used to help understand the method and core idea of ​​the present invention, and at the same time, for those skilled in the art, there are changes in the form for implementing the invention and the scope of application according to the idea of ​​the present invention. Therefore, the contents of this specification should not be understood as limitations on the present invention. [Explanation of symbols]

[0039] 1-Hull 2-Ultrasonic vibration plate 3-Ultrasonic Control System 4-Vibration Plate Bracket

Claims

1. A novel method for treating cyanobacterial blooms, comprising: Calculate the volume of the water body, add polyaluminum chloride powder in the amount of 5-10 ppm, and before adding the polyaluminum chloride powder, mix it thoroughly with water to completely dissolve the powder, and then spray it evenly along the water surface; agglomeration step (1); a stirring step (2) in which the boat is moved back and forth across the water surface to uniformly mix the added polyaluminum chloride with the lake water; and (3) an ultrasonic treatment step in which, after leaving the solution to stand for a certain period of time, a mobile ultrasonic treatment device is used to move back and forth across the surface of the water body to perform ultrasonic treatment.

2. The method for combined treatment of new cyanobacterial blooms described in claim 1, characterized in that if the water volume of the water body is within 700,000 cubic meters, at least one of the mobile ultrasonic treatment devices is used for treatment every day, and the daily treatment time is 6 hours or more.If the water volume of the treatment area is more than 700,000 cubic meters, at least one more mobile ultrasonic treatment device is added for every 700,000 cubic meters increase, and ultrasonic treatment is performed simultaneously.

3. 2. The method for combined treatment of new cyanobacterial blooms according to claim 1, wherein the mobile ultrasonic treatment device comprises a hull, an ultrasonic vibration plate, and an ultrasonic control system, and a plurality of ultrasonic vibration plates are installed on both sides of the hull, each of the ultrasonic vibration plates is electrically connected to the ultrasonic control system, and the ultrasonic control system is installed on the hull.

4. The method for combined treatment of new cyanobacterial blooms as described in claim 3, characterized in that each of the ultrasonic vibration plates is installed on a vibration plate bracket, and each of the vibration plate brackets is fixedly attached to the side of the hull.

5. The method for combined treatment of new cyanobacterial blooms as described in claim 3, characterized in that three ultrasonic vibration plates are installed on each side of the hull, and the ultrasonic vibration plates on both sides are installed symmetrically with respect to the hull.

6. The combined treatment method for new cyanobacterial blooms according to claim 3, characterized in that the rated power of the ultrasonic vibration plate is 2.1 kW and the ultrasonic frequency is 28 kHz.

7. The combined treatment method for new cyanobacterial blooms according to claim 3, characterized in that the hull is equipped with a marine battery or a gasoline / diesel generator for providing electrical energy to the ultrasonic vibration plate and the ultrasonic control system.

8. The combined treatment method for new cyanobacterial blooms according to claim 4, wherein the vibration plate bracket is a stainless steel bracket.

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