Method and system for removing algae in landscape water body

Abstract

The invention discloses a method and system for removing algae in a landscape water body, and the method comprises the following steps: S1, separating algae water into a concentrated solution and a diluted solution by using a microfiltration machine, S2, carrying out coagulation and / or air flotation impurity removal on the diluted solution to obtain a clear solution and a waste solution, S3, carrying out ultraviolet radiation disinfection and killing on the clear solution, and S4, discharging the concentrated solution and / or the waste solution into a wetland for ecological treatment, according to the method for removing algae in the landscape water body, concentrated liquid and diluted liquid are physically separated through a microfilter, classified treatment is carried out according to different algae particle sizes, the cost of coagulation, air flotation and algae killing is reduced, and the method has the advantages that the cost is low, the cost is low, the cost is low, and the method is suitable for large-scale popularization and application. And the water-soluble chitosan biological coagulant is non-toxic and easy to explain, has cationic groups, is easy for negative charges on the surfaces of algae particles to generate electric neutralization, promotes the algae particles to quickly destabilize and settle, realizes safe removal of the algae in the water body, and is simple, efficient and easy to implement.

Description

Technical Field

[0001] The present invention belongs to the technical field of landscape water body algae removal, and more specifically, relates to a landscape water body algae removal method and system. Background Art

[0002] Landscape water bodies are mostly artificially constructed closed or slow-flowing water bodies, especially urban landscape water bodies, which have small water area, shallow water depth, poor fluidity, and weak self-purification ability. Fish feeding, surface rainwater and sewage inflow, and dead branches and leaves deposition easily cause eutrophication of water bodies. When the environmental conditions (temperature and light) are suitable, algae in these eutrophic water bodies will multiply in large numbers, and even water blooms will occur. The large-scale growth of algae causes the water body to produce odor, increase turbidity, and decrease transparency, which seriously affects the aerobic activities and growth and reproduction of aquatic plants and animals, and even causes death, deterioration of the sensory properties of the water body, and gradual loss of landscape functions; and algae cells release algae toxins during their growth. Even after they die, rot, or even decompose, the algae toxins in the cells will be released into the water body in large quantities as the cells disintegrate, continuously endangering human health.

[0003] Conventional algae in-situ killing leads to the release of algae toxins and the circulation of nutrients back to the water body. Only algae-water separation can remove algae fundamentally. Among them, coagulation process is the most feasible and effective treatment technology for algae-water separation, especially the combined filter, air flotation, ultrasound, pre-oxidation and other processes can achieve deep removal of algae, but the filter is easy to clog and the removal rate is not ideal. The technical costs of ultrasound and pre-oxidation are high, and it is easy to destroy algae cells and release algae toxins. Commonly used coagulants are mostly chemical agents such as polyaluminium chloride (PAC) and polyacrylamide (PAM). Such agents not only affect environmental safety and bring health risks to humans, but also affect the utilization value of algae mud after separation. For example, patent CN111592178B is a nearshore water body blue algae treatment device and treatment method thereof, which uses a pressurizing mechanism to destroy blue algae pseudo-cavitation, group structure and cell structure, and adds polyaluminium chloride, polyacrylamide and other flocculants to the tail water after air flotation and centrifugal separation. It is precipitated and concentrated in a sedimentation tank, and the clear water overflows into the wetland for purification and then discharged into the nearshore water body. The flocculant used is an aluminum salt flocculant, which cannot be accurately measured. There is a risk of excessive use of aluminum ions, resulting in excessive aluminum ions in the effluent. In addition, the release of algal toxins will be aggravated during the destruction of algal cells, which poses a risk of endangering biological safety. Patent CN 107098515 B is an integrated device and method for the adsorption, killing and concentration of water bloom blue algae. The device uses a sponge to absorb, squeeze and collect blue algae, kill algae with microcurrent, and then filter and squeeze it into a cake for discharge through a filter. Since the sponge is easy to clog and the filtration speed is slow, and microcurrent algae killing can easily cause algal cells to rupture, there is also a risk of releasing algal toxins.

[0004] In summary, there is a lack of an efficient, safe, and environmentally friendly algae removal system and treatment method for separating and removing algae from landscape water bodies. Summary of the invention

[0005] The purpose of the present invention is to provide a method for removing algae from landscape water bodies in view of the deficiencies in the prior art, so as to solve the problem that the existing separation and removal of algae from landscape water bodies lacks an efficient, safe, and environmentally friendly algae removal system and treatment method.

[0006] In order to achieve the above object, the present invention provides a method for removing algae from landscape water bodies, comprising:

[0007] S1. Use a microfiltration machine to separate the algae water into a concentrated solution and a diluted solution, wherein the algae particle size of the concentrated solution is larger than that of the diluted solution;

[0008] S2, coagulating and / or flotating the dilute liquid to remove impurities to obtain a clear liquid and a waste liquid;

[0009] S3, sterilizing the clear liquid by ultraviolet radiation;

[0010] S4. Discharging the concentrated liquid and / or waste liquid into wetlands for ecological treatment;

[0011] Preferably, a biocoagulant is used for coagulation treatment of the clear liquid;

[0012] More preferably, the biocoagulant is a water-soluble chitosan biocoagulant.

[0013] Optionally, the wetland operates intermittently or in rotation to ensure an ecological purification cycle.

[0014] Optionally, the decomposition products of the algae are used as carbon sources by the wetland for denitrification or as nutrients absorbed by wetland plants, and the wetland plants are harvested regularly to ensure absorption capacity.

[0015] Optionally, the microfilter filters algae with a particle size of more than 50 μm.

[0016] Optionally, the method further includes controlling the dosage of the biocoagulant according to the chlorophyll A content.

[0017] Optionally, the wetland effluent and the disinfection water after ultraviolet radiation disinfection are mixed and discharged into the landscape water body.

[0018] The present invention also provides a landscape water body algae removal system, comprising:

[0019] Microfiltration machine;

[0020] An air flotation device, the air flotation device comprises a reaction tank and a reagent dosing system, the liquid inlet of the air flotation device is connected to the dilute liquid outlet of the microfiltration machine, and the reagent dosing system is used for adding a biological coagulant;

[0021] A wetland connected to a concentrated liquid outlet of the microfiltration machine and a waste liquid outlet of the air flotation device;

[0022] An ultraviolet algaecide device, wherein the inlet end of the ultraviolet algaecide device is connected to the outlet end of the clear liquid of the air flotation device.

[0023] Optionally, the flotation device is provided with a chlorophyll A monitor.

[0024] Optionally, a plurality of wetlands are provided, and each wetland is used in rotation and in a cycle.

[0025] Optionally, the wetland is a subsurface flow wetland.

[0026] The present invention provides a method for removing algae from landscape water bodies, which has the following beneficial effects:

[0027] This method for removing algae from landscape water bodies physically separates concentrated liquid and dilute liquid through a microfiltration machine, classifies and treats algae particles of different sizes, reduces the costs of coagulation, flotation and algaecide, and the water-soluble chitosan biocoagulant is non-toxic and easy to explain, and has cationic groups that are easy to neutralize the negative charges on the surface of algae particles, causing them to quickly destabilize and settle, thereby achieving safe removal of algae from water bodies. It is simple, efficient and easy to implement.

[0028] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The above and other objects, features and advantages of the present invention will become more apparent through a more detailed description of exemplary embodiments of the present invention in conjunction with the accompanying drawings, wherein like reference numerals generally represent like components throughout the exemplary embodiments of the present invention.

[0030] Figure 1 A schematic flow chart of a method for removing algae from a landscape water body according to an embodiment of the present invention is shown.

[0031] Description of reference numerals:

[0032] 1. Microfiltration machine; 2. Flotation device; 3. Wetland; 4. Ultraviolet algaecide device. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention will be described in more detail below. Although the preferred embodiments of the present invention are described below, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided to make the present invention more thorough and complete, and to fully convey the scope of the present invention to those skilled in the art.

[0034] like Figure 1As shown, the methods for removing algae from landscape water bodies include:

[0035] S1, using a microfiltration machine 1 to separate the algae water into a concentrated solution and a diluted solution, wherein the algae particle size of the concentrated solution is larger than that of the diluted solution;

[0036] S2, coagulating and / or flotating the dilute liquid to remove impurities to obtain a clear liquid and a waste liquid;

[0037] S3, sterilizing the clear liquid by ultraviolet radiation;

[0038] S4, discharging the concentrated liquid and / or waste liquid into wetland 3 for ecological treatment;

[0039] Preferably, a biocoagulant is used for coagulation treatment of the clear liquid;

[0040] More preferably, the biocoagulant is a water-soluble chitosan biocoagulant.

[0041] Specifically, the microfilter 1 physically filters and separates the algae water, and the algae particles with a particle size of less than 50 μm are filtered to form a dilute liquid. The dilute liquid is treated with algae water coagulation by a biological coagulant. While separating the algae water, the phosphorus content in the water can also be reduced. The biological coagulant has the characteristics of being easily degradable and non-toxic. Among them, the modified water-soluble chitosan biological coagulant has good water solubility, is easy to disperse in water, and produces a coagulation effect. And because chitosan itself carries cationic groups, it is easy for the negative charge on the surface of the algae particles to be electrically neutralized, which promotes its rapid destabilization and sedimentation. The dilute liquid after coagulation enters the flotation and impurity removal. Since the algae particles in the dilute liquid are small in size (less than 50 μm), they are close to the bubble size generated by the flotation and dissolved gas, and the adhesion effect is better, which can better achieve floating separation. The clear liquid after impurity removal is sterilized by ultraviolet radiation. Ultraviolet radiation sterilization is an effective algae killing method that can inhibit the growth and reproduction of algae, especially for microalgae with a particle size of less than 50 μm. The average inactivation rate can reach 95%, which is simple to use and cost-effective. At the same time, algae particles with a diameter of more than 50 μm are blocked and sent to the concentrate. The concentrate contains a lot of algae and has a large algae particle size, and directly enters the wetland 3 for ecological treatment. Because it is a biological coagulant without harmful substances, wastewater can also enter the wetland 3 as nutrients for ecological treatment. The ecological treatment process of wetland 3 does not require artificial regulation and additional treatment of algae mud. It can be discharged when it meets the water quality requirements. At the same time, the wastewater and concentrate are mixed and discharged into the wetland 3, and the two dilute each other to avoid local eutrophication.

[0042] Furthermore, the dilute liquid and the concentrated liquid are treated separately, and the large-sized algae do not need to be floated and consume coagulants, which saves reagents and shortens the flotation time compared to unified treatment.

[0043] In this embodiment, the wetland 3 operates intermittently or in rotation to ensure the ecological purification cycle.

[0044] Specifically, the wetland 3 has an ecological purification cycle, and intermittent drainage or multiple wetland 3 rotation operations are used to avoid overloading of the wetland 3 and causing ecological environment collapse.

[0045] In this embodiment, the decomposition products of algae are used as carbon sources by wetland 3 for denitrification or as nutrients to be absorbed by wetland plants, and plants in wetland 3 are harvested regularly to ensure absorption capacity.

[0046] Specifically, by ensuring the growth of wetland plants, creating a "hungry" state in the wetland can speed up the treatment of concentrated liquid and wastewater.

[0047] In this embodiment, the microfilter 1 filters algae with a particle size of 50 μm or more.

[0048] Specifically, the concentrated liquid and the diluted liquid are filtered and separated according to the best objects for disinfection by ultraviolet radiation.

[0049] In this embodiment, the dosage of the biocoagulant is also controlled according to the chlorophyll A content.

[0050] Specifically, the chlorophyll A index of the incoming water is tested online at the same time, and the corresponding relationship between the chlorophyll A index and the dosage of the agent can be used to achieve scientific and accurate addition of the agent.

[0051] In this embodiment, the wetland effluent and the disinfection water after ultraviolet radiation disinfection are mixed and discharged into the landscape water body.

[0052] The present invention also provides a landscape water body algae removal system, comprising:

[0053] Microfiltration machine 1;

[0054] The air flotation device 2 includes a reaction tank and a reagent dosing system. The liquid inlet of the air flotation device 2 is connected to the dilute liquid outlet of the microfiltration machine 1. The reagent dosing system is used to add a biological coagulant.

[0055] Wetland 3, wetland 3 is connected to the concentrated liquid outlet of microfiltration machine 1 and the waste liquid outlet of air flotation device 2;

[0056] The ultraviolet algaecide device 4 has an inlet end connected to an outlet end of the clear liquid of the air flotation device 2 .

[0057] During use, the landscape water body is physically filtered and separated from the algae water by the microfilter 1 (impurities can be roughly filtered before the microfilter 1), and the algae particles with a particle size of less than 50 μm are filtered into a dilute liquid. The dilute liquid is treated with algae water coagulation by a biological coagulant. While separating the algae water, the phosphorus content in the water can also be reduced. The biological coagulant has the characteristics of easy degradation and non-toxicity. Among them, the modified water-soluble chitosan biological coagulant has good water solubility, is easy to disperse in water, and produces a coagulation effect. And because chitosan itself carries cationic groups, it is easy for the negative charge on the surface of the algae particles to be electrically neutralized, which promotes its rapid destabilization and sedimentation. The dilute liquid after coagulation enters the flotation impurity removal. Since the algae particles in the dilute liquid are small in size (less than 50 μm), they are close to the bubble size generated by the flotation dissolved gas, and the adhesion effect is better, which can better achieve floating separation. The clear liquid after impurities removal is sterilized by ultraviolet radiation. Ultraviolet radiation sterilization is an effective algae killing method, which can inhibit the growth and reproduction of algae, especially for microalgae with a particle size of less than 50μm. The average inactivation rate can reach 95%. It is simple to use and cost-effective. At the same time, algae particles with a particle size of more than 50μm are blocked into concentrated liquid. The concentrated liquid contains a lot of algae and the algae particle size is large. It directly enters wetland 3 for ecological treatment. Because it is a biocoagulant that is pollution-free and degradable, wastewater can also enter wetland 3 as nutrients for ecological treatment. Then the wastewater and concentrated liquid enter wetland 3, and the wetland effluent after ecological treatment and the disinfection water after ultraviolet sterilization are mixed and discharged into the landscape water body. The wetland effluent is used to supplement the nutrients of the landscape water body, and the landscape water body's own water body capacity can digest the algae corpses. The self-circulation of the landscape water body is realized, and the problem of excessive algae in the landscape water body is eliminated.

[0058] In this embodiment, the air flotation device 2 is provided with a chlorophyll A monitor.

[0059] In this embodiment, a plurality of wetlands 3 are provided, and each wetland 3 is used in rotation and in a circular manner.

[0060] In this embodiment, the wetland 3 is a submerged flow wetland.

[0061] When the method for removing algae from landscape water bodies in this embodiment is used, the use of water body landscape is taken as an example:

[0062] The average algae particle size of the landscape lake water was measured to be 51 μm, mainly composed of green algae. The average water quality index data of the inlet water was: algae density was 7.8×10 7 / L, chlorophyll A was 329μg / L, ss was 33mg / L, and TP was 0.91mg / L.

[0063] The algae water is transported to the microfilter 1 through a water pump. A drum filter is installed in the microfilter 1, and a self-cleaning system is provided. The pore size of the filter is between 50-100 μm. After the initial algae-water separation in the microfilter 1, the separated concentrated liquid is discharged to the wetland 3 for ecological purification treatment.

[0064] After the initial algae-water separation by the microfiltration machine 1, the dilute liquid enters the flotation device 2, which is equipped with a reagent dosing system. The reagent dosing system accurately controls the amount of reagent dosing according to the changes in the chlorophyll A index; the actual reagent dosing concentration is between 0.5-2mg / L according to the on-site water quality. The results show that coagulation flotation can remove about 80% of TP while achieving algae-water separation. The separated wastewater is discharged to the wetland 3 for ecological purification treatment.

[0065] The clear liquid after flotation separation still contains a small amount of small-size algae particles. This part of the clear liquid is treated with algaecide by the ultraviolet algaecide device 4 to further kill and remove algae in the water without destroying the algae cells. The treated disinfected water is discharged back to the landscape lake environment.

[0066] Wetland 3 is operated in parallel rotation, with water flowing in and out intermittently. The algae cell particles in the algae slurry settle and decompose within a residence period (2-4 weeks). The decomposition products provide carbon sources and nutrients for Wetland 3. The wetland plants planted there are harvested regularly every month. The denitrification and denitrification and plant absorption of Wetland 3 achieve deep purification of algae water. Finally, the purified wetland effluent is discharged into the landscape lake environment.

[0067] This case shows that after the water body is purified by the system, the average water quality index data of the effluent is:

[0068] The algae density is 7.7×10 6 / L, chlorophyll A is 20μg / L, ss is 5mg / L, TP is 0.12mg / L. Compared with the influent water quality, the algae density removal rate is 90%, the chlorophyll A removal rate is 94%, the ss removal rate is 85%, and the TP removal rate reaches 87%. The overall algae removal effect is good.

[0069] The embodiments of the present invention have been described above, and the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. The method of removing algae from landscape water bodies shall include: Book S1. Use a microfiltration machine to separate the algae water into a concentrated solution and a diluted solution, wherein the algae particle size of the concentrated solution is larger than that of the diluted solution; S2, coagulating and / or flotating the dilute liquid to remove impurities to obtain a clear liquid and a waste liquid; S3, sterilizing the clear liquid by ultraviolet radiation; S4. Discharging the concentrated liquid and / or waste liquid into wetlands for ecological treatment; Preferably, a biocoagulant is used for coagulation treatment of the clear liquid; More preferably, the biocoagulant is a water-soluble chitosan biocoagulant.

2. The method for removing algae from landscape water bodies according to claim 1, characterized in that: The wetland operates intermittently or in rotation to ensure an ecological purification cycle.

3. The method for removing algae from landscape water bodies according to claim 2, characterized in that: It also includes the products produced by algae decomposition being used as a carbon source by the wetland for denitrification or absorbed by wetland plants as nutrients. The wetland plants are harvested regularly to ensure absorption capacity.

4. The method for removing algae from landscape water bodies according to claim 1, characterized in that: The microfilter filters algae with a particle size of more than 50 μm.

5. The method for removing algae from landscape water bodies according to claim 1, characterized in that: It also includes controlling the dosage of the biocoagulant according to the chlorophyll A content.

6. The method for removing algae from landscape water bodies according to claim 1, characterized in that: The wetland effluent and the disinfection water after ultraviolet radiation disinfection are mixed and discharged into the landscape water body.

7. Landscape water algae removal system, characterized in that: include: Microfiltration machine; An air flotation device, the air flotation device comprises a reaction tank and a reagent dosing system, the liquid inlet of the air flotation device is connected to the dilute liquid outlet of the microfiltration machine, and the reagent dosing system is used for adding a biological coagulant; A wetland connected to a concentrated liquid outlet of the microfiltration machine and a waste liquid outlet of the air flotation device; An ultraviolet algaecide device, wherein the inlet end of the ultraviolet algaecide device is connected to the outlet end of the clear liquid of the air flotation device.

8. The landscape water algae removal system according to claim 7, characterized in that: The air flotation device is provided with a chlorophyll A monitor.

9. The landscape water algae removal system according to claim 7, characterized in that: There are multiple wetlands, and each wetland is used in rotation and circulation.

10. The landscape water algae removal system according to claim 7, characterized in that: The wetland is a subsurface flow wetland.

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