Method for removing pollutants in water by adopting composite process

Abstract

The invention discloses a method and a system for removing pollutants in water by adopting a composite process. The method comprises the following steps: adding a set amount of flocculant into a water body to be treated to form semi-flocculation flocs in the water body; and removing the semi-flocculated flocs by adopting an air flotation process. By means of the scheme, the semi-flocculation floc which is longer in chain, more fluffy, easier to float, easy to break and easy to float to the upper layer can be formed, after bubbles are introduced into a water body where the semi-flocculation floc is formed through the combination of the semi-flocculation floc and the air flotation process, the semi-flocculation floc is attached to the bubbles and easily floats to the water surface along with the bubbles, and therefore the water body with the semi-flocculation floc is formed. Therefore, pollutants in the water are efficiently removed, the reflux ratio of the air floatation process is reduced, the energy consumption of the air floatation tank is greatly reduced, and the cost for removing the pollutants in the water is reduced.

Description

Technical Field

[0001] The present invention generally relates to the technical field of water pollutant treatment, and more specifically, to a method for removing pollutants from water using a composite process. Background Art

[0002] In the prior art, flotation is usually used to remove pollutants in water. Flotation is an efficient flotation process, which is particularly suitable for treating raw water with low temperature, low turbidity, high algae, high color and organic pollution. Flotation also has a certain removal effect on soluble organic matter in water, and is more commonly used in sewage treatment and environmental water purification. When using flotation to remove pollutants in water, a large number of tiny bubbles are mainly introduced into the water. Based on the principles of surface tension and buoyancy, the suspended particles in the water adhere to the bubbles due to the hydrophobicity of the particle surface, float to the water surface with the bubbles, and then remove the floating impurities through scraping equipment. For example, in water containing tiny particles such as algae, algae particles can adhere to bubbles well and separate from water. Compared with the sedimentation method, the flotation method has a better removal effect on suspended particles with a specific gravity close to that of water.

[0003] However, the use of flotation to remove pollutants in water requires a 5%-10% reflux ratio to ensure that there are enough bubbles in the water to react with the pollutants in the water and ensure a good removal effect. A high reflux ratio leads to higher energy consumption in the process, thereby increasing the process cost.

[0004] In view of this, there is an urgent need to provide a solution for removing pollutants in water using a composite process to effectively remove pollutants in water and reduce the energy consumption and cost of the process. Summary of the invention

[0005] In order to at least solve one or more of the technical problems mentioned above, the present application proposes a solution of removing pollutants in water by using a composite process in multiple aspects.

[0006] In a first aspect, the present application provides a method for removing pollutants in water using a composite process, comprising: adding a set amount of flocculant to the water to be treated to form semi-flocculated flocs in the water; and removing the semi-flocculated flocs using a flotation process.

[0007] In some embodiments, the set amount is the product of the optimal flocculant dosage and a set coefficient, wherein the set coefficient is greater than 1, and the optimal flocculant dosage is less than the flocculant dosage corresponding to the minimum turbidity of the water body after adding the flocculant.

[0008] In some embodiments, the difference between the optimal amount of flocculant added and the amount of flocculant added corresponding to the minimum turbidity of the water body after the flocculant is added is equal to a preset difference.

[0009] In some embodiments, the flocculant is polyaluminium chloride.

[0010] In some embodiments, a pretreatment agent is added to the water to be treated before adding a set amount of flocculant to the water to be treated.

[0011] In some embodiments, a pH adjuster is added to the water to be treated while adding a set amount of flocculant to the water to be treated.

[0012] In some embodiments, after the semi-flocculated flocs are removed by flotation process, the water from which the semi-flocculated flocs have been removed is passed into a filtration tank for filtration.

[0013] In some embodiments, a carbon layer is provided in the filtration pool, and the thickness of the carbon layer is 1.5m-2.0m.

[0014] In the second aspect, the present application provides a system for removing pollutants in water using a composite process, wherein the pollutants in water are removed using the method for removing pollutants in water using a composite process as described in any embodiment of the first aspect, and the system comprises: a reaction tank for mixing the water body to be treated with a set amount of added flocculant to form semi-flocculated flocs; a flotation tank for removing the semi-flocculated flocs in the water body that has formed the semi-flocculated flocs; a filtration tank for filtering the water body from which the semi-flocculated flocs have been removed; and a clear water tank for storing the water body that has been treated in the filtration tank and disinfected.

[0015] In some embodiments, the system further comprises a water distribution well, which is used to distribute and regulate water volume for the water to be treated, and input the distributed and regulated water into the reaction tank; wherein a set amount of flocculant is added to the reaction tank or the water distribution well.

[0016] By adopting the composite process to remove pollutants from water as provided above, the embodiment of the present application can form semi-flocculated flocs which are longer in chain, more fluffy, easier to float, easier to break and easier to float to the upper layer. By combining the semi-flocculated flocs and the flotation process, after the flotation process introduces air bubbles into the water body for forming the semi-flocculated flocs, the semi-flocculated flocs adhere to the air bubbles and easily float to the water surface with the air bubbles, thereby efficiently removing pollutants from water, and reducing the reflux ratio of the flotation process, greatly reducing the energy consumption of the flotation tank, and thus reducing the cost involved in removing pollutants from water. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] By reading the detailed description below with reference to the accompanying drawings, the above and other purposes, features and advantages of the exemplary embodiments of the present application will become easy to understand. In the accompanying drawings, several embodiments of the present application are shown in an exemplary and non-limiting manner, and the same or corresponding reference numerals represent the same or corresponding parts, wherein: Figure 1 An exemplary flow chart of a method for removing pollutants from water using a composite process according to an embodiment of the present application is shown; Figure 2 A schematic diagram of the curve of effluent turbidity-flocculant dosage in an embodiment of the present application is shown; Figure 3 An exemplary structural block diagram of a system for removing pollutants from water using a composite process according to some embodiments of the present application is shown; Figure 4 An exemplary structural block diagram of a system for removing pollutants from water using a composite process according to other embodiments of the present application is shown. DETAILED DESCRIPTION

[0018] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present application.

[0019] It should be understood that the terms "include" and "comprising" used in the specification and claims of the present application indicate the presence of described features, wholes, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, wholes, steps, operations, elements, components and / or collections thereof.

[0020] It should also be understood that the terms used in this application specification are only for the purpose of describing specific embodiments and are not intended to limit the present application. As used in this application specification and claims, unless the context clearly indicates otherwise, the singular forms of "a", "an" and "the" are intended to include plural forms. It should also be further understood that the term "and / or" used in this application specification and claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes these combinations.

[0021] The specific implementation of the present application is described in detail below with reference to the accompanying drawings.

[0022] Figure 1 An exemplary flow chart of a method 100 for removing pollutants from water using a composite process according to an embodiment of the present application is shown.

[0023] like Figure 1 As shown, in step S110, a set amount of flocculant is added to the water body to be treated to form semi-flocculated flocs in the water body.

[0024] In some embodiments of the present application, the water to be treated is first distributed and adjusted in the water distribution well, and then introduced into the reaction tank for mixing and reaction with the drugs including flocculants added to form semi-flocculated flocs. Specifically, a set amount of flocculants can be added to the water distribution well or the reaction tank.

[0025] In other embodiments of the present application, the water to be treated is directly introduced into the reaction tank to mix and react with the added medicine including the flocculant to form semi-flocculated flocs. Specifically, a set amount of flocculant is added into the reaction tank.

[0026] In the aforementioned embodiment, a stirring device may be provided in the reaction tank to stir the added medicine including flocculant and the water to be treated, so that the water to be treated and the medicine including flocculant can fully react.

[0027] In the aforementioned embodiments, the preset turbidity value may be set according to actual needs and historical experience, and the present application does not impose any limitation thereto.

[0028] In the embodiments of the present application, the aforementioned flocculant is polyaluminium chloride.

[0029] In the embodiment of the present application, the set amount is the product of the optimal dosage of the flocculant and the set coefficient.

[0030] Specifically, the aforementioned setting coefficient is greater than 1.

[0031] In the embodiments of the present application, the setting coefficient is set according to actual needs and historical experience, and the present application does not limit the specific value corresponding to it. For example, in some embodiments of the present application, the setting coefficient is set to 1.2, and the setting amount is 1.2×the optimal flocculant dosage.

[0032] Specifically, the aforementioned optimal flocculant dosage is less than the flocculant dosage corresponding to the minimum turbidity of the water body after adding the flocculant, and the difference between the optimal flocculant dosage and the flocculant dosage corresponding to the minimum turbidity of the water body after adding the flocculant is equal to the preset difference.

[0033] In the embodiments of the present application, the amount of flocculant added corresponding to when the turbidity of the water body is the smallest after the flocculant is added is the optimal dosing point, and the optimal dosing point can be determined through a beaker experiment.

[0034] In some embodiments of the present application, a curve between flocculant dosage and effluent turbidity is constructed through a beaker experiment to determine the optimal dosing point.

[0035] Figure 2 A schematic diagram of the curve of effluent turbidity-flocculant dosage in an embodiment of the present application is shown.

[0036] like Figure 2 As shown, when the flocculant dosage is 1.3 mg / L, the effluent turbidity is the smallest, that is, the optimal dosage point is 1.3 mg / L.

[0037] In the embodiments of the present application, the aforementioned preset difference can be set according to actual needs and historical experience, but at least the set amount must be greater than the corresponding amount of flocculant added when the turbidity of the water body is the minimum after the addition of the flocculant, so that an excess of flocculant is added to the water body to be treated, thereby forming semi-flocculated flocs.

[0038] Specifically, semi-flocculated flocs are an intermediate state between complete flocculation and micro-flocculation. They are fluffy multi-nuclear flocs that are easy to float and remove by adding excess flocculants. Their size is relatively small, generally between a few microns and tens of microns. Compared with the traditional flocculation process, its flocculation reaction is lighter and will not form large and dense flocs like conventional flocculation. Since semi-flocculated flocs are lighter than flocculants, they can be quickly removed by flotation.

[0039] In the embodiment of the present application, before adding a set amount of flocculant to the water body to be treated, a pretreatment agent is added to the water body to be treated. Specifically, the pretreatment agent includes permanganate, powdered activated carbon (PAC) and the like.

[0040] Specifically, the aforementioned permanganate includes lithium permanganate, sodium permanganate, potassium permanganate, ammonium permanganate, calcium permanganate, barium permanganate, zinc permanganate, magnesium permanganate and the like.

[0041] As a strong oxidant, permanganate is mainly used to remove organic pollutants, color and odor substances in water through oxidation. It can effectively destroy or change the structure of some organic matter, making it easier to be removed by subsequent treatment steps.

[0042] Powdered activated carbon (PAC) has a very large specific surface area and a well-developed pore structure, which enables it to efficiently adsorb trace organic pollutants, pesticide residues, industrial chemicals and other difficult-to-degrade organic compounds in water.

[0043] By adding pretreatment agents such as permanganate and powdered carbon to the water to be treated, permanganate can decompose large molecular organic matter into small molecules through oxidation, which are then adsorbed by powdered carbon. This not only improves the removal efficiency, but also reduces the dosage required for using any one agent alone. This combination is particularly suitable for treating water bodies with complex components or affected by multiple types of pollution sources, which can reduce the workload of subsequent treatment stages and ultimately achieve higher purification standards.

[0044] In the embodiment of the present application, a pH regulator is added to the water body to be treated while adding a set amount of flocculant to the water body to be treated. Specifically, the pH regulator includes lime, carbon dioxide, and the like.

[0045] In the embodiments of the present application, the amount and type of pH regulator added can be controlled according to the types of pollutants in the water body to be treated, so that the pH of the water body to be treated satisfies the formation of the largest number of semi-flocculated flocs and / or the fastest speed of forming semi-flocculated flocs, thereby effectively removing turbidity, algae, and some volatile small molecular organic matter, thereby improving the treatment efficiency of pollutants in the water.

[0046] After step S110 is performed, in step S120, the semi-flocculated flocs are removed by using an air flotation process.

[0047] In the embodiment of the present application, when the semi-flocculated flocs are removed by adopting the flotation process, the water in which the semi-flocculated flocs are formed is passed into the flotation tank for treatment.

[0048] In the embodiments of the present application, flotation facilities and scum removal facilities may be provided in the flotation tank.

[0049] In an embodiment of the present application, the flotation facility includes an air compressor, an air dissolving tank and an air release device. The air dissolving tank is connected to the air compressor and connected to the clean water tank through a reflux pump and a valve. The air release device is connected to the air dissolving tank. The air compressor inputs compressed air into the air dissolving tank. When the pressure in the air dissolving tank reaches a preset value, the reflux pump is started, and the valve is slowly opened to input clean water into the air dissolving tank to dissolve the compressed air. Then, the water dissolved with air passes through the air release device, and the pressure is instantly reduced to release a large number of fine bubbles.

[0050] When the water body in which semi-flocculated flocs are formed enters the flotation tank, air bubbles are injected into the water body in which semi-flocculated flocs are formed through the flotation facility, so that the semi-flocculated flocs in the water body adhere to the air bubbles and float to the water surface with the air bubbles.

[0051] In the embodiment of the present application, the scum removal facility may be a scraper. The scraper is located above the separation zone of the flotation tank. The scraper periodically scrapes the waste scum including semi-flocculated flocs floating on the water surface into the scum discharge tank for discharge through reciprocating motion. At the beginning of the separation zone, the scraper is lowered and inserted into the liquid surface, and the scum is scraped forward and scraped into the scum discharge tank; at the end, the scraper is lifted and separated from the liquid surface, and the scraper returns to start the next cycle.

[0052] In the embodiments of the present application, by adding an excessive amount of flocculation flocs, the collision chance of particles is increased, and a semi-flocculation floc with multiple condensation cores is formed. The adsorption and bridging capacity of the semi-flocculation floc is increased, and the semi-flocculation floc is overgrown, having the characteristics of longer chains, being more fluffy, being easier to float and being easy to break, and being easy to float to the upper layer. After air bubbles are introduced into the water body in which the semi-flocculation floc is formed by the flotation process, the semi-flocculation floc adheres to the air bubbles and easily floats to the water surface with the air bubbles. Therefore, a shallower effective water depth and a smaller reflux ratio can be used in the flotation process.

[0053] Compared with the prior art where the flotation process requires a water depth of 2m-7m, in the embodiment of the present application, it is only necessary to set the effective water depth corresponding to the flotation process in the flotation process to be greater than or equal to 1m and less than 2m, thereby effectively reducing the construction cost.

[0054] Compared with the prior art, the flotation process requires a reflux ratio of 5%-10% to ensure that there are enough bubbles in the water to react with the pollutants in the water and ensure a good removal effect. In the embodiment of the present application, the reflux ratio of the flotation process only needs to be set to 1%-5%, thereby greatly reducing the energy consumption of the flotation process.

[0055] In an embodiment of the present application, after step S120 is performed, the water body from which the semi-flocculated flocs have been removed is passed into a filtration tank for filtration.

[0056] In an embodiment of the present application, a carbon layer is provided in the filter tank.

[0057] In an embodiment of the present application, the thickness of the carbon layer is 1.5m-2.0m.

[0058] In the embodiments of the present application, the carbon layer uses activated carbon, and the activated carbon is selected as crushed briquette carbon (or raw coal crushed carbon), the activated carbon strength is greater than 95%, and the carbon layer selects customized filter material, and the particle size of the customized filter material is 16×30 mesh. By selecting the grading of the customized filter material and the activated carbon strength of more than 95%, it can be similar to the filter material particle size of the sand filter, which can improve the turbidity removal efficiency, increase the service life of the activated carbon, and effectively remove odors and organic matter. In addition, the semi-flocculated flocs in the water body are removed by the flotation process, and when they are passed into the filter pool, the surface load of the filter pool can be reduced, and the service life of the activated carbon can be increased.

[0059] In an embodiment of the present application, after the water body is filtered to remove the semi-flocculated flocs in the water body, a disinfectant is added to the filtered water body, and after the water body is disinfected by the disinfectant, the obtained water body is passed into a clean water tank.

[0060] In summary, through the scheme of removing pollutants in water using a composite process as provided above, the embodiment of the present application can form semi-flocculated flocs that are longer in chain, more fluffy, easier to float, easier to break and easier to float to the upper layer. By combining the semi-flocculated flocs and the flotation process, after the flotation process introduces air bubbles into the water body for forming the semi-flocculated flocs, the semi-flocculated flocs adhere to the air bubbles and easily float to the water surface with the air bubbles, thereby efficiently removing pollutants in the water, and reducing the reflux ratio of the flotation process, greatly reducing the energy consumption of the flotation tank, thereby reducing the cost involved in removing pollutants in the water.

[0061] An embodiment of the present application also provides a system for removing pollutants from water using a composite process. The system may use the aforementioned composite process method 100 for removing pollutants from water to remove pollutants from water, or may use other methods to remove pollutants from water, which is not limited in the present application.

[0062] Figure 3 An exemplary structural block diagram of a system for removing pollutants from water using a composite process according to some embodiments of the present application is shown.

[0063] like Figure 3 As shown, the system 300 includes a reaction tank 310 , a flotation tank 320 , a filtration tank 330 and a clean water tank 340 .

[0064] Specifically, the reaction tank 310 is used for mixing the water to be treated with a set amount of added flocculant to form semi-flocculated flocs.

[0065] Specifically, a set amount of flocculant is added to the reaction tank 310 .

[0066] Specifically, the flotation tank 320 is used to remove semi-flocculated flocs in the water body where the semi-flocculated flocs are formed.

[0067] Specifically, the filter tank 330 is used to filter the water from which the semi-flocculated flocs have been removed.

[0068] Specifically, the clean water tank 340 is used to store water that has been processed by the filter tank and disinfected.

[0069] When the system 300 uses the aforementioned composite process method 100 for removing pollutants from water to remove pollutants from water, the aforementioned step S110 is performed in the reaction tank 310, the aforementioned step S120 is performed in the flotation tank 320, and the aforementioned step of passing the water body from which the semi-flocculated flocs have been removed into the filter tank for filtration is performed in the filter tank 330. The specific execution process can be referred to above and will not be repeated here.

[0070] Figure 4 An exemplary structural block diagram of a system for removing pollutants from water using a composite process according to other embodiments of the present application is shown.

[0071] like Figure 4 As shown, the system 400 includes a water distribution well 410 , a reaction tank 420 , a flotation tank 430 , a filtration tank 440 and a clean water tank 450 .

[0072] Specifically, the water distribution well 410 is used to distribute and regulate the amount of water to be treated, and input the distributed and regulated water into the reaction tank 420 .

[0073] Specifically, a set amount of flocculant may be added to the water distribution well 410 or the reaction tank 420 .

[0074] Specifically, the reaction tank 420 is used for mixing the water to be treated with a set amount of added flocculant to form semi-flocculated flocs.

[0075] Specifically, the flotation tank 430 is used to remove semi-flocculated flocs in the water body where the semi-flocculated flocs are formed.

[0076] Specifically, the filter tank 440 is used to filter the water from which the semi-flocculated flocs have been removed.

[0077] Specifically, the clean water tank 450 is used to store water that has been processed by the filter tank and disinfected.

[0078] When the system 400 uses the aforementioned composite process method 100 for removing pollutants from water to remove pollutants from water, the aforementioned step S110 is performed in the reaction tank 420, or the aforementioned step S110 is performed in the water distribution well 410 and the reaction tank 420, the aforementioned step S120 is performed in the flotation tank 430, and the aforementioned step of passing the water body from which the semi-flocculated flocs have been removed into the filter tank for filtration is performed in the filter tank 440. The specific execution process can be referred to above and will not be repeated here.

[0079] Although multiple embodiments of the present application have been shown and described herein, it is obvious to those skilled in the art that such embodiments are provided only by way of example. Those skilled in the art can think of many changes, modifications and alternatives without departing from the thought and spirit of the present application. It should be understood that in the process of practicing the present application, various alternatives to the embodiments of the present application described herein can be adopted. The attached claims are intended to limit the scope of protection of the present application, and therefore cover equivalents or alternatives within the scope of these claims.

Claims

1. A method for removing pollutants from water using a composite process, characterized in that: include: adding a set amount of flocculant to the water to be treated to form semi-flocculated flocs in the water; The semi-flocculated flocs are removed by adopting an air flotation process.

2. The method for removing pollutants from water using a composite process according to claim 1, characterized in that: The set amount is the product of the optimal amount of flocculant added and a set coefficient, wherein the set coefficient is greater than 1, and the optimal amount of flocculant added is less than the amount of flocculant added corresponding to the minimum turbidity of the water body after the flocculant is added.

3. The method for removing pollutants from water using a composite process according to claim 2, characterized in that: The difference between the optimal amount of flocculant added and the amount of flocculant added corresponding to the minimum turbidity of the water body after the flocculant is added is equal to the preset difference.

4. The method for removing pollutants from water using a composite process according to claim 1, characterized in that: The flocculant is polyaluminium chloride.

5. The method for removing pollutants from water using a composite process according to claim 1, characterized in that: Before adding a set amount of flocculant to the water body to be treated, a pretreatment agent is added to the water body to be treated.

6. The method for removing pollutants from water using a composite process according to claim 5, characterized in that: While adding a set amount of flocculant to the water body to be treated, a pH regulator is added to the water body to be treated.

7. The method for removing pollutants from water using a composite process according to claim 1, characterized in that: After the semi-flocculated flocs are removed by the flotation process, the water from which the semi-flocculated flocs have been removed is passed into a filter tank for filtration.

8. The method for removing pollutants from water using a composite process according to claim 7, characterized in that: A carbon layer is arranged in the filter pool, and the thickness of the carbon layer is 1.5m-2.0m.

9. A system for removing pollutants from water using a composite process, characterized in that: The method for removing pollutants in water by using a composite process as described in any one of claims 1 to 8 is used to remove pollutants in water, and the system comprises: A reaction tank, used for mixing the water to be treated with a set amount of added flocculant to form semi-flocculated flocs; The flotation tank is used to remove the semi-flocculated flocs in the water body where the semi-flocculated flocs are formed; A filter tank is used to filter the water from which the semi-flocculated flocs have been removed; The clean water tank is used to store water that has been treated in the filter tank and disinfected.

10. The system for removing pollutants from water using a composite process according to claim 9, characterized in that: The system also includes a water distribution well, which is used to distribute and regulate the water volume of the water to be treated, and input the distributed and regulated water into the reaction tank; Therein, a set amount of flocculant is added to the reaction tank or the water distribution well.

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