Water purification method without adding medicament

Abstract

The invention relates to the technical field of water purification, in particular to a water purification method without adding chemicals, which comprises the following steps: raw water of a target water source permeates into a water collecting well through soil, and gravel in the soil primarily filters the raw water of the target water source; a membrane assembly immersed in the bottom of the water collecting well is used for conducting secondary filtration on the water obtained after preliminary filtration, a biological membrane is loaded on the surface of the membrane assembly, the membrane assembly is used for achieving self-cleaning, and the membrane assembly runs with the filtration flux lower than the balance flux of the biological membrane; and the water pump is used for pumping water subjected to secondary filtration to the water storage tank. Therefore, the problems of high water purification cost, high complexity, high maintenance cost and the like in the prior art are solved.

Description

Technical Field

[0001] The present application relates to the technical field of water purification, and in particular to a water purification method without adding chemicals. Background Art

[0002] Some remote areas in my country use shallow well water as drinking water, which is usually supplemented by water from nearby rivers and other places through soil filtration. The water quality of these well waters is better than that of river water, but there are still microbial risks if they are drunk directly.

[0003] Ultrafiltration has been widely used in drinking water treatment because it can effectively intercept particulate matter, colloids, pathogenic microorganisms, etc. However, there are two problems with the ultrafiltration process: 1. Poor removal of soluble pollutants; 2. Membrane pollution. In order to solve these two problems, water plants currently often use complex pretreatment, such as coagulation-sedimentation-filtration. This greatly increases the operating cost and maintenance difficulty of the ultrafiltration process. Summary of the invention

[0004] The present application provides a water purification method without adding chemicals to solve the problems of high water purification cost, complexity, and maintenance cost in the prior art.

[0005] The first aspect of the present application provides a water purification method without the need for adding chemicals, comprising the following steps: allowing raw water from a target water source to infiltrate a water collection well through the soil, wherein the sand and gravel in the soil perform a preliminary filtration on the raw water from the target water source; performing a secondary filtration on the water after the primary filtration using a membrane assembly immersed in the bottom of the water collection well, wherein a biofilm is loaded on the surface of the membrane assembly for achieving self-cleaning of the membrane assembly, and the membrane assembly operates with a filtration flux lower than the equilibrium flux of the biofilm, and uses a water pump to pump the water after the secondary filtration to a water storage tank.

[0006] Optionally, the water permeability of the soil between the target water source and the water collection well meets a preset standard.

[0007] Optionally, the actual distance between the water collection well and the target water source is within a target distance range, and the depth of the water collection well is lower than the depth of the target water source.

[0008] Optionally, a filter layer is provided in the water collection well, wherein sand and gravel are provided in the filter layer.

[0009] Optionally, a fixed raised sealing cover plate is provided on the upper part of the water collection well, wherein the height of the raised cover plate is higher than a preset height above the ground.

[0010] Optionally, the membrane assembly adopts external pressure immersion.

[0011] Optionally, the method further includes: monitoring the water level of the water collection well; if the water level is lower than the top of the membrane assembly, the membrane assembly stops filtering.

[0012] Optionally, the method further includes: controlling the filtration flux of the membrane assembly by using a flow control valve and a frequency converter.

[0013] Therefore, this application has at least the following beneficial effects:

[0014] The embodiment of the present application can filter the raw water of the target water source through the soil to intercept some large particles in the water, and flow it into the water collection well, and use the membrane assembly at the bottom of the water collection well to perform secondary filtration on the water after the preliminary filtration, so as to further improve the water quality of the effluent. The combined filtration based on the preliminary filtration of the soil and the secondary filtration of the membrane assembly can achieve water purification, and the biofilm loaded on the surface of the membrane assembly, the microorganisms can effectively degrade the membrane pollutants deposited on the membrane, that is, self-cleaning can be achieved when pollution occurs, effectively alleviating membrane pollution, and maintaining the filtration flux of the membrane assembly lower than the self-stable equilibrium flux of the biofilm, without the need for physical and chemical cleaning, the water purification complexity and cost are low, and the water purification method is more green and low-carbon. Thus, the technical problems of high water purification cost, complexity, and maintenance cost in the prior art are solved.

[0015] Additional aspects and advantages of the present application will be given in part in the description below, and in part will become apparent from the description below, or will be learned through the practice of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The above and / or additional aspects and advantages of the present application will become apparent and easily understood from the following description of the embodiments in conjunction with the accompanying drawings, in which:

[0017] Figure 1 A schematic diagram of a water purification method without adding chemicals according to an embodiment of the present application;

[0018] Figure 2 This is a diagram showing the effect of long-term filtration achieved by biofilm self-cleaning according to an embodiment of the present application;

[0019] Figure 3 This is a diagram showing the effect of the biofilm on the membrane surface on the membrane self-cleaning according to the embodiment of the present application;

[0020] Figure 4 This is a diagram showing the effect of improving the water quality of membrane filtered water by soil filtration according to an embodiment of the present application. DETAILED DESCRIPTION

[0021] Embodiments of the present application are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present application, and should not be construed as limiting the present application.

[0022] The following is a description of the water purification method without adding a medicament in the embodiment of the present application with reference to the accompanying drawings. In view of the complex pretreatment often used in water plants mentioned in the above background technology center, for example: coagulation-sedimentation-filtration. This greatly increases the operating cost and maintenance difficulty of the ultrafiltration process. The present application provides a water purification method without adding a medicament, in which the target water source water can be initially filtered through the soil to intercept some large particles in the water, flow into the water collection well, and use the membrane assembly at the bottom of the water collection well to perform secondary filtration on the water after the preliminary filtration, further improve the effluent water quality, and achieve water purification based on the combined filtration of the preliminary filtration of the soil and the secondary filtration of the membrane assembly, and the biofilm loaded on the surface of the membrane assembly, the microorganisms can effectively degrade the membrane pollutants deposited on the membrane, that is, self-cleaning can be achieved when pollution occurs, effectively alleviate membrane pollution, and maintain the filtration flux of the membrane assembly lower than the self-stabilizing equilibrium flux of the biofilm, without the need for physical and chemical cleaning, the water purification complexity and cost are low, and the water purification method is more green and low-carbon. Thus, the problems of high water purification cost, complexity, and maintenance cost in the prior art are solved.

[0023] Specifically, the water purification method without adding chemicals comprises the following steps:

[0024] In step S101, raw water from a target water source is infiltrated into a water collection well through the soil, wherein the sand and gravel in the soil preliminarily filters the raw water from the target water source.

[0025] The target water source may be a river, lake or other water body.

[0026] It is understandable that the embodiment of the present application can infiltrate the target water source raw water into the water collection well through the soil, and use the sand, gravel and microorganisms in the soil to preliminarily filter the target water source raw water.

[0027] In step S102, the water after the initial filtration is secondary filtered using a membrane assembly immersed in the bottom of the water collection well, wherein a biofilm is loaded on the surface of the membrane assembly for self-cleaning of the membrane assembly, and the membrane assembly operates with a filtration flux lower than the equilibrium flux of the biofilm.

[0028] The filtration flux can be set according to the specific situation. To maintain the equilibrium flux of microbial activity on the biofilm, for example, 10 L m -2 h -1 .

[0029] It can be understood that the embodiments of the present application can use a membrane assembly immersed in the bottom of the water collection well to perform secondary filtration on the water after primary filtration, so as to realize a filtration method that combines primary filtration using soil and secondary filtration by the membrane assembly, and the surface of the membrane assembly is loaded with a biofilm, and the microorganisms can effectively degrade the membrane pollutants deposited on the membrane, that is, self-cleaning can be achieved when pollution occurs, effectively alleviating membrane pollution, and maintaining the filtration flux of the membrane assembly lower than the self-stabilizing equilibrium flux of the biofilm, without the need for physical and chemical cleaning, the water purification complexity and cost are low, and no chemicals need to be added, and the water purification method is more green and low-carbon.

[0030] In step S103, the water after the secondary filtration is pumped to the water storage tank by a water pump.

[0031] It is understandable that the embodiment of the present application can utilize a water pump to pump the water after secondary filtration to a water storage tank to achieve a complete water purification process.

[0032] In the embodiment of the present application, the water permeability of the soil between the target water source and the water collection well meets the preset standard.

[0033] Among them, the preset standard can be set according to the specific situation. For example, the permeability can be described by the permeability coefficient of the soil. For example, if the permeability coefficient is greater than a certain threshold, the preset standard is met.

[0034] It is understandable that the geological conditions of the soil between the water collection well and the target water source should be good and have strong permeability, which will help improve the natural filtration effect of water and reduce the burden of membrane component filtration.

[0035] In addition, it should be noted that if the permeability does not meet the requirements, the permeability can be increased by artificially filling quartz sand, etc. The depth of the collection well is recommended not to exceed the aerobic zone of the soil layer.

[0036] In the embodiment of the present application, the actual distance between the water collection well and the target water source is within the target distance range, and the depth of the water collection well is lower than the depth of the target water source.

[0037] It can be understood that in the embodiment of the present application, the actual distance between the water collection well and the target water source is within the target range, that is, the distance is moderate, and the water extraction efficiency will not be affected by the long distance, and the depth of the water collection well is lower than the depth of the target water source, which helps to utilize the natural pressure of groundwater and reduce pumping energy consumption. In addition, the actual radius of the water collection pool is within the preset radius range, which can ensure the effective working area of ​​the membrane assembly and improve the filtration efficiency. For example, the water collection well is set 5 to 15 meters below the water level in the water source area.

[0038] In an embodiment of the present application, a filter layer is provided in the water collection well, wherein sand and gravel are provided in the filter layer.

[0039] Among them, sand and gravel are arranged in the filter layer, and the particle size of the sand and gravel is smaller than the preset particle size. The preset particle size can be set according to the specific situation, for example, the particle size can be less than 3mm.

[0040] It is understandable that in the embodiment of the present application, a filter layer is also provided in the water collection well to prevent the infiltrated water from carrying away the soil in the dam body or the foundation when flowing out.

[0041] In an embodiment of the present application, a fixed raised sealing cover plate is provided on the upper part of the water collection well, wherein the height of the raised cover plate is higher than a preset height above the ground.

[0042] Among them, the height of the protrusion is higher than the preset height of the ground, and the preset height can be set according to the specific situation, such as 0.5m.

[0043] It is understandable that the embodiment of the present application may be provided with a fixed raised sealing cover plate on the upper part of the water collection well, and the cover plate is higher than a preset height from the ground to ensure that the water quality is not polluted.

[0044] In the embodiment of the present application, the membrane assembly adopts external pressure immersion.

[0045] It can be understood that the membrane assembly in the embodiment of the present application is of external pressure immersion type, so that the membrane assembly can be directly immersed in water to reduce the complexity of water purification.

[0046] In an embodiment of the present application, the method further includes: monitoring the water level of the water collection well; if the water level is lower than the top of the membrane assembly, the membrane assembly stops filtering.

[0047] It is understandable that the embodiment of the present application can also monitor the water level of the water collection well, and when the water level is lower than the top of the membrane assembly, the membrane assembly stops filtering.

[0048] In an embodiment of the present application, it also includes: using a flow control valve and a frequency converter to control the filtration flux of the membrane assembly.

[0049] It is understandable that the embodiments of the present application can utilize a flow control valve and a frequency converter to control the filtration flux of the membrane assembly to maintain the filtration flux of the membrane assembly lower than the self-stabilizing equilibrium flux of the biofilm.

[0050] The following is a specific embodiment to describe the water purification method of the present application without adding chemicals. The water from East Lake is used as the water source and the water collection pool is used as the water collection well. The membrane assembly is directly immersed in the water collection well, and a water pump is used to pump out the produced water. The implementation process of the water purification method is as follows: Figure 1 As shown, the water pump is operated by the electric energy provided by the solar panel.

[0051] Preferably, 1. The well should be located at a place with good geology on the shore, 50 to 500 meters away from the river or lake, and the soil should have strong permeability. If the permeability is insufficient, quartz sand can be artificially filled to increase the permeability.

[0052] 2. It is recommended that the depth of the well should not exceed the aerobic zone of the soil layer. The depth should be 5 to 15 meters lower than the water level of the river or lake, and the diameter of the wellhead should be 1 to 5 meters.

[0053] 3. A fixed sealing cover is installed on the top of the well to prevent water pollution. The cover is raised and shall not be less than 0.5m above the ground.

[0054] 4. A filter layer is set in the well, and the particle size of the filler in the filter layer is less than 3mm.

[0055] 5. Use external pressure to immerse the ultrafiltration membrane assembly and place the membrane assembly directly at the bottom of the well.

[0056] 6. Use pipeline pump to provide driving force for filtration, and control membrane flux to less than 10Lm through flow control valve and frequency converter. -2 h -1 .

[0057] 7. The surface of the membrane component is loaded with biofilm, and the self-cleaning of the membrane is achieved by relying on the activity of microorganisms in the biofilm.

[0058] 8. Monitor the well water level. When the level is lower than the top of the membrane assembly, filtration needs to be suspended.

[0059] The influent DOC is 7.48~8.28mgL -1 , UV 254 0.06~0.08cm -1 Take the turbidity as 3.24~3.57NTU and the temperature as 19~25℃ as an example.

[0060] Water from Donghu Lake was selected as the influent water. Part of the influent water passed directly through the ultrafiltration membrane assembly (i.e., the control group), and the other part of the influent water was preliminarily filtered through the sand column before entering the ultrafiltration membrane assembly (the solution of this application). The water in the ultrafiltration membrane was pumped out by a pump into the water storage tank.

[0061] After preliminary filtration by sand column and then filtration by ultrafiltration membrane, the effluent flux increases, realizing the long-term self-cleaning process of biofilm. Figure 2 After preliminary filtration by the sand column and then filtration by the ultrafiltration membrane, the membrane fouling layer becomes thinner and the structure becomes loose, achieving the self-cleaning effect of the biofilm on the membrane surface. Figure 3 After preliminary filtration by sand column, the effluent turbidity, POC, DOC and UV after filtration by ultrafiltration membrane 254 The concentration of was significantly reduced, achieving the purpose of improving the water quality of membrane filtration water after soil filtration. Figure 4 This shows that the water purification method without adding chemicals in the embodiment of the present application, a low-carbon, low-consumption green water purification method using chemical pretreatment, can be applied to areas with decentralized water supply using surface water as the water source, and can significantly improve the effluent water quality and effectively alleviate membrane pollution.

[0062] According to the water purification method without adding chemicals proposed in the embodiment of the present application, the target water source raw water can be initially filtered through the soil to intercept some large particles in the water and flow into the water collection well, and the membrane component at the bottom of the water collection well can be used to perform secondary filtration on the water after the initial filtration to further improve the effluent water quality. The combined filtration based on the initial filtration of the soil and the secondary filtration of the membrane component can achieve water purification, and the biofilm loaded on the surface of the membrane component and the microorganisms can effectively degrade the membrane pollutants deposited on the membrane, that is, self-cleaning can be achieved when pollution occurs, effectively alleviating membrane pollution, and maintaining the filtration flux of the membrane component lower than the self-stabilizing equilibrium flux of the biofilm, without the need for physical and chemical cleaning, the water purification complexity and cost are low, and the water purification method is more green and low-carbon.

[0063] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or N embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0064] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of this application, "N" means at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0065] Any process or method description in a flowchart or otherwise described herein may be understood to represent a module, fragment or portion of code comprising one or N executable instructions for implementing the steps of a custom logical function or process, and the scope of the preferred embodiments of the present application includes alternative implementations in which functions may not be performed in the order shown or discussed, including performing functions in a substantially simultaneous manner or in reverse order depending on the functions involved, which should be understood by technicians in the technical field to which the embodiments of the present application belong.

[0066] It should be understood that the various parts of the present application can be implemented by hardware, software, firmware or a combination thereof. In the above embodiment, the N steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one or a combination of multiple of the following technologies known in the art: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0067] A person skilled in the art may understand that all or part of the steps in the method for implementing the above-mentioned embodiment may be completed by instructing related hardware through a program, and the program may be stored in a computer-readable storage medium, which, when executed, includes one or a combination of the steps of the method embodiment.

Claims

1. A water purification method without adding chemicals, characterized in that: The following steps are involved: The target water source raw water is infiltrated into the water collection well through the soil, wherein the sand and gravel in the soil preliminarily filters the target water source raw water; The water after the primary filtration is filtered for a second time by using a membrane assembly immersed in the bottom of the water collection well, wherein a biofilm is loaded on the surface of the membrane assembly for achieving self-cleaning of the membrane assembly, and the membrane assembly operates with a filtration flux lower than the equilibrium flux of the biofilm; The water after secondary filtration is pumped to the water storage tank using a water pump.

2. The water purification method without adding chemicals according to claim 1, characterized in that: The water permeability of the soil between the target water source and the water collection well meets a preset standard.

3. The water purification method without adding chemicals according to claim 1, characterized in that: The actual distance between the water collection well and the target water source is within a target distance range, and the depth of the water collection well is lower than the depth of the target water source.

4. The water purification method without adding chemicals according to claim 1, characterized in that: A filter layer is arranged in the water collection well, wherein sand and gravel are arranged in the filter layer.

5. The water purification method without adding chemicals according to claim 1, characterized in that: A fixed raised sealing cover plate is provided on the upper part of the water collection well, wherein the height of the raised cover plate is higher than a preset height of the ground.

6. The water purification method without adding chemicals according to claim 1, characterized in that: The membrane assembly is of external pressure immersed type.

7. The water purification method without adding chemicals according to claim 1, characterized in that: Also includes: monitoring the water level of the water collection well; If the water level is lower than the top of the membrane module, the membrane module stops filtering.

8. The water purification method without adding chemicals according to claim 1, characterized in that: Also includes: The filtration flux of the membrane assembly is controlled by a flow control valve and a frequency converter.

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