Sand land surface reinforcement method and system based on microbial mineralization

Abstract

The invention belongs to the technical field of ecological environment engineering, and particularly relates to a sand land surface reinforcement method and system based on microbial mineralization, and the method comprises the following steps: step 1, determining an injection point on a sand land to be reinforced; step 2, injecting a bacterial liquid containing urease-producing bacteria into the surface of the sand land to be reinforced at the position of the injection point; step 3, injecting a cementing solution into the surface of the sand land to be reinforced at the position of the injection point; the cementing solution comprises urea and calcium chloride.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of ecological environment engineering, in particular to a sand surface reinforcement method and system based on microbial mineralization. BACKGROUND

[0002] In sand areas, due to strong wind erosion, problems such as loose soil structure, water and soil loss, and vegetation degradation are common, which leads to a decrease in the stability of the ecological system and triggers a chain of ecological crises such as land desertification and frequent sandstorms. Traditional sand fixation technologies such as chemical consolidant spraying and surface artificial covering have defects such as environmental pollution, high maintenance cost, or insufficient initial sand fixation efficiency. Although biological crust technology has ecological advantages, it has a long natural formation period and cannot meet the demand for rapid sand fixation. Microbial-induced calcium carbonate precipitation (MICP) technology can enhance the soil's resistance to wind erosion by inducing calcium carbonate precipitation through microbial metabolism, and is a green sand fixation technology. However, existing MICP sand fixation technology has significant shortcomings: vertical injection method leads to uneven distribution of cementing solution in the soil layer, and the mineralization effect is significantly different; in-situ activation method is greatly affected by environmental temperature, humidity and other factors, and the sand fixation effect is unstable. Therefore, it is urgent to develop an efficient, stable and environmentally friendly sand surface reinforcement method. SUMMARY

[0003] The present application provides a sand surface reinforcement method and system based on microbial mineralization to solve the problems of uneven mineralization and unstable sand fixation effect in the prior art. To achieve the above purpose, the present application adopts the following technical solutions: A sand surface reinforcement method based on microbial mineralization, comprising the following steps: Step one: determining injection points on the sand to be reinforced; Step two: injecting bacteria solution containing urease-producing bacteria into the sand surface to be reinforced at the position of the injection point; Step three: injecting a cementing solution into the sand surface to be reinforced at the position of the injection point; the cementing solution contains urea and calcium chloride.

[0004] Optionally, in step one, the injection points are distributed in a grid-like staggered manner on the sand to be reinforced, and the distance between adjacent injection points is 30 to 50 cm.

[0005] Optionally, in step two, the urease-producing bacteria are Sporosarcina pasteurii, and the concentration of the urease-producing bacteria in the bacteria solution is controlled at an OD600 value of 0.8-1.2. Preferably, in step two, the injection amount of the bacteria solution is 1.0-5.0 L.

[0006] Optionally, in the step two, calcium chloride solution is first added to the injection point, and then the bacteria solution containing urease-producing bacteria is injected into the surface of the sand to be reinforced at the injection point.

[0007] Optionally, in the step three, the cementation solution contains 0.3-0.8 mol / L CaCl2 and 0.3-0.8 mol / L urea. Preferably, in the step three, the injection amount of the cementation solution is 2.0-6.0 L.

[0008] Preferably, in the step three, after injecting the bacteria solution for 12-20 hours, the cementation solution is injected into the surface of the sand to be reinforced at the injection point.

[0009] Optionally, it further includes a step four: covering the surface layer of the sand to be reinforced with a breathable sunshade material and spraying water to maintain the water content of the sand to be reinforced at 15%-25%.

[0010] A sand surface reinforcement system based on microbial mineralization, comprising: an injector for inserting into an injection point on the sand to be reinforced; a bacteria solution injection device for injecting the bacteria solution containing urease-producing bacteria into the surface of the sand to be reinforced at the injection point; a cementation solution injection device for injecting the cementation solution into the surface of the sand to be reinforced at the injection point; a control device for controlling the injector, the bacteria solution injection device, and the cementation solution injection device to perform the sand surface reinforcement method based on microbial mineralization.

[0011] Optionally, it further includes a shading and humidifying device for covering the surface layer of the sand to be reinforced with a breathable sunshade material and spraying water.

[0012] Optionally, the bacteria solution injection device includes a bacteria solution tank connected with a bacteria solution injection pump; the bacteria solution injection pump is used to pump the bacteria solution in the bacteria solution tank into the injector. The cementation solution injection device includes a cementation solution tank connected with a cementation solution injection pump; the cementation solution injection pump is used to pump the cementation solution in the cementation solution tank into the injector.

[0013] An electronic device, comprising a memory and a processor, the memory and the processor being connected; The memory stores computer instructions, and the processor executes the computer instructions to perform the sand surface reinforcement method based on microbial mineralization.

[0014] Compared with the prior art, the present application can obtain the following beneficial effects: The method of the present application is efficient in construction, the equipment is portable, and large-area mechanical operation in the field can be realized to shorten the construction period. The mineralized product is calcium carbonate, and there is no chemical pollution, which meets the requirements of ecological restoration and is eco-friendly. Through the staggered grid distribution combined with adjustable depth injection, the uneven distribution problem of traditional vertical injection is solved, and the reinforcement effect is uniform. Through strain pre-fixing and surface temperature and humidity control, the interference of environmental factors on the MICP reaction is reduced, the stability of sand fixation effect is improved, and the environmental adaptability is strong. It is multifunctional and compatible, and takes into account soil structure reinforcement and air permeability maintenance, creating conditions for subsequent vegetation restoration. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0016] Figure 1 The present application is a structural schematic diagram. DETAILED DESCRIPTION

[0017] In order to more clearly illustrate the above-mentioned purposes, features and advantages of the present application, the following will further describe the present application in combination with the drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0018] In the following description, many specific details are set forth in order to provide a thorough understanding of the present application, however, the present application can also be implemented in other ways different from those described herein, therefore, the protection scope of the present application is not limited by the specific embodiments disclosed below.

[0019] In the present application, the terms "mounting", "connection", "connection", "fixing" and the like should be understood in a broad sense, for example, "connection" can be fixed connection, or detachable connection, or integral connection; "connection" can be direct connection, or indirect connection through intermediate medium. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0020] In the description of the present application, it should be understood that the terms "inner", "outer" and the like indicate the positional or location relationship based on the positional or location relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or units referred to must have a particular direction, be constructed and operated in a particular orientation, therefore, it cannot be understood as a limitation on the present application.

[0021] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "a specific embodiment" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0022] The present application discloses a kind of sand surface reinforcement method based on microbial mineralization, comprising the following steps: Step one: determine injection point on the sand to be reinforced treatment; Step two: the bacteria liquid containing urease-producing bacteria is injected into the sand surface below to be reinforced treatment at the position of the injection point; Step three: after a period of time of injecting bacteria liquid, cementing solution is injected into the sand surface below to be reinforced treatment at the position of the injection point;The cementing solution includes urea and calcium chloride.

[0023] The Microbially Induced Carbonate Precipitation (MICP) used in the present application is a biological technology that promotes the mineralization of calcium carbonate through microbial metabolic activity, which is environmentally friendly, has mild reaction conditions, and is widely used in civil engineering, environmental remediation and other fields. The principle is that microorganisms produce carbonate ions through urea decomposition, denitrification, sulfate reduction and other metabolic processes, which combine with calcium ions to form calcium carbonate precipitate. By inducing calcium carbonate precipitation through microbial metabolism, the soil erosion resistance can be enhanced, which is a green sand fixation technology.

[0024] Further, in the step one, the injection points are staggered in a grid pattern on the sand to be reinforced treatment, and the distance between adjacent injection points is 30 to 50 centimeters.

[0025] Further, in the step two, calcium chloride solution is first added to the injection point, and then the bacteria liquid containing urease-producing bacteria is injected into the sand surface below to be reinforced treatment at the position of the injection point. Before injection, the sand body is pretreated by low-concentration fixing solution containing CaCl2 to enhance the adsorption capacity of bacteria on the sand surface and improve the subsequent mineralization efficiency.

[0026] Further, the urease-producing bacteria in step two is Sporosarcina pasteurii, and the concentration of the bacteria in the bacteria solution is controlled to be 0.8-1.2 OD600.

[0027] Bacillus pasteurii is a kind of bacteria with high mineralization capacity in the technology of microbial induced carbonate precipitation (MICP), and has high urease activity, which can quickly decompose urea to generate ammonium ion and carbonate ion, and form calcite type calcium carbonate precipitation in the presence of calcium ion. And its cell surface has more negative charge, which can efficiently capture calcium ion and promote the nucleation and growth of calcium carbonate crystal.

[0028] Further, in step two, the injection amount of the bacteria solution is 1.0-5.0 L.

[0029] Further, in step three, the cementation solution comprises 0.3-0.8 mol / L CaCl2 and 0.3-0.8 mol / L urea. Further, in step three, the injection amount of the cementation solution is 2.0-6.0 L.

[0030] Preferably, in step three, after injecting the bacteria solution for 12-20 hours, the cementation solution is injected into the surface of the sand to be reinforced under the injection point.

[0031] Further, it further comprises step four: covering the surface layer of the sand to be reinforced with a breathable sunshade material and spraying water to maintain the water content of the sand to be reinforced to 15%-25%.

[0032] The breathable sunshade material can be a sunshade net. The sunshade net (also known as a light-blocking net) is generally a net-shaped covering material woven from polyethylene (HDPE), polypropylene (PP) and the like, and is mainly used in the fields of agriculture, construction, outdoor sunshade and the like, and has the functions of light blocking, cooling, moisture retention, anti-aging and the like. In agriculture, it can be used for sun protection and cooling in summer and frost prevention in winter.

[0033] The application also provides a sand surface reinforcement system based on microbial mineralization according to the above method, which comprises: a syringe for inserting into an injection point on the sand to be reinforced; a bacteria solution injection device for injecting a bacteria solution containing urease-producing bacteria into the surface of the sand to be reinforced at the injection point; a cementation solution injection device for injecting a cementation solution into the surface of the sand to be reinforced at the injection point; A control device is configured to control the injector, the bacteria solution injection device and the cementing solution injection device to perform the above-mentioned sand surface reinforcement method based on microbial mineralization.

[0034] Further, the system further comprises a shading and humidifying device configured to cover the sand surface to be reinforced with a breathable shading material and spray water.

[0035] Further, the bacteria solution injection device comprises a bacteria solution tank connected with a bacteria solution injection pump; the bacteria solution injection pump is configured to pump the bacteria solution in the bacteria solution tank into the injector. The cementing solution injection device comprises a cementing solution tank connected with a cementing solution injection pump; the cementing solution injection pump is configured to pump the cementing solution in the cementing solution tank into the injector.

[0036] The application further provides an electronic device comprising a memory and a processor, wherein the memory and the processor are connected; The memory stores computer instructions, and the processor executes the computer instructions to perform the above-mentioned sand surface reinforcement method based on microbial mineralization.

[0037] Embodiment 1 First, as shown in Figure 1 The embodiment provides a sand surface reinforcement system based on microbial mineralization, which comprises: An injector 3 is configured to be inserted into an injection point on the sand to be reinforced; the injector 3 comprises a liquid medicine cartridge and a needle below the liquid medicine cartridge, and the needle is configured to be inserted into a position below the sand surface where injection is needed; a plurality of injectors 3 are provided to facilitate injection treatment at multiple points at the same time.

[0038] A bacteria solution injection device is configured to inject bacteria solution containing urease-producing bacteria into the sand surface to be reinforced at the injection point; the bacteria solution injection device comprises a bacteria solution tank connected with a bacteria solution injection pump 1; the bacteria solution injection pump 1 is configured to pump the bacteria solution in the bacteria solution tank into the injector 3.

[0039] A cementing solution injection device is configured to inject cementing solution into the sand surface to be reinforced at the injection point; the cementing solution injection device comprises a cementing solution tank connected with a cementing solution injection pump 2; the cementing solution injection pump 2 is configured to pump the cementing solution in the cementing solution tank into the injector 3.

[0040] A control device is configured to control the injector, the bacteria solution injection device and the cementing solution injection device to perform the above-mentioned sand surface reinforcement method based on microbial mineralization, which comprises the following steps: Step one: determine injection points on the sand to be reinforced; adopt a grid-like staggered point distribution method, set the distance between adjacent injection points to 30-50 cm to construct continuous overlapping solidification areas; staggered multi-point grid injection layout: set injection points at the set distance to form overlapping solidification areas, improve overall reinforcement uniformity and continuity.

[0041] Step two: determine injection points at a depth of 30 cm below the surface of the sand to be reinforced, first add calcium chloride solution to the injection points, then inject bacteria solution containing urease-producing bacteria to the injection points below the surface of the sand to be reinforced; the urease-producing bacteria are Sporosarcina pasteurii, and the concentration of the urease-producing bacteria in the bacteria solution is controlled to be OD600 value 0.8-1.2. The injection amount of the bacteria solution is 2.5 L. During implementation, an adjustable depth injection needle can also be used to achieve directional reinforcement of sand at different depths. Before injection, the sand body is pretreated with a low concentration fixing solution containing CaCl2 (mass fraction 1-2%) to enhance the adsorption capacity of the bacteria on the sand surface and improve the subsequent mineralization efficiency.

[0042] Step three: 12 hours after injecting the bacteria solution, inject a cementation solution to the injection points below the surface of the sand to be reinforced; the cementation solution contains urea and calcium chloride. Calcium carbonate is induced to precipitate on the surface of the sand particles through MICP reaction. The cementation solution contains 0.5 mol / L CaCl2 and 0.5 mol / L urea; the injection amount of the cementation solution is 3 L.

[0043] Step four: during construction, lay a breathable sunshade net on the ground and periodically spray water to maintain the moisture content of the sand to be reinforced at 15%-25%. Optimize the microbial activity environment and prevent surface cracking.

[0044] Specifically, the method for preparing the bacteria solution containing urease-producing bacteria in step two is as follows: Prepare the culture medium: use nutrient solution (10 g / L of tryptone, 20 g / L of yeast extract powder, 20 g / L of urea, 5 g / L of NaCl, pH about 7.5). Inoculate and culture: inoculate the strain of Sporosarcina pasteurii in the above culture medium and cultivate at 30°C for 24 h. Growth control: monitor the OD600 value of the bacteria solution by spectrophotometer, and take it when the value reaches 0.8-1.2. Pre-treatment before use: let the bacteria solution stand or centrifuge at low speed to remove part of the metabolites, and resuspend it with sterile saline solution for on-site injection.

[0045] The method in the present application has high construction efficiency, portable equipment, can realize field large-area mechanized operation, and shortens the construction period. The mineralized product is calcium carbonate, has no chemical pollution, meets the ecological restoration requirements, and is ecological friendly. Through staggered grid distribution combined with adjustable depth injection, the uneven distribution problem of traditional vertical injection is solved, and the reinforcement effect is uniform. Through strain pre-fixing and surface temperature and humidity control, the interference of environmental factors on the MICP reaction is reduced, the stability of sand fixation effect is improved, and the environmental adaptability is strong. It is multifunctional and compatible, takes into account soil structure reinforcement and air permeability maintenance, and creates conditions for subsequent vegetation restoration.

[0046] Based on the above-mentioned sand surface reinforcement method based on microbial mineralization, an electronic device is also provided in the embodiments of the present application. The electronic device includes one or more processors, memories, and interfaces for connecting various components, including high-speed interfaces and low-speed interfaces. Various components are communicatively connected to each other using different buses, and can be installed on a common motherboard or in other ways as needed. The processor can process instructions executed within the electronic device, including instructions stored in the memory or on the memory to display graphical information on a GUI on an external input / output device, such as a display device coupled to the interface.

[0047] In some optional embodiments, multiple processors and / or multiple buses can be used with multiple memories and multiple memories, if necessary. Also, multiple electronic devices can be connected, each device providing part of the necessary operations (for example, as a server array, a group of blade servers, or a multi-processor system). The processor can be a central processor, a network processor, or a combination thereof. The processor can further include a hardware chip. The hardware chip can be an application-specific integrated circuit, a programmable logic device, or a combination thereof. The programmable logic device can be a complex programmable logic device, a field programmable logic gate array, a general array logic, or any combination thereof. The memory stores instructions executable by the at least one processor to cause the at least one processor to execute the double cell recognition method shown in the above embodiments.

[0048] The memory can include a program storage area and a data storage area, wherein the program storage area can store an operating system, application programs required by at least one function; the data storage area can store data created according to the use of the electronic device, etc. In addition, the memory can include a high-speed random access memory, and can also include a non-transitory memory, such as at least one magnetic disk storage device, a flash memory device, or other non-transitory solid-state memory device. In some optional embodiments, the memory can include a memory remotely disposed relative to the processor, which can be connected to the electronic device through a network. Examples of the network include but are not limited to the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof.

[0049] The memory can include volatile memory, such as random access memory, and the memory can also include non-volatile memory, such as flash memory, hard disk, or solid state disk. The memory can also include a combination of the above-mentioned kinds of memory.

[0050] The electronic device also includes an input device and an output device. The processor, the memory, the input device, and the output device can be connected by a bus or other means.

[0051] The input device can receive input digital or character information, and generate key signal input relating to user settings and function controls of the electronic device, such as a touch screen, a keypad, a mouse, a trackpad, a touchpad, a pointing stick, one or more mouse buttons, a trackball, a joystick, etc. The output device can include a display device, an auxiliary lighting device (e.g., an LED), a haptic feedback device (e.g., a vibration motor), etc. The display device includes, but is not limited to, a liquid crystal display, a light emitting diode, a display, and a plasma display. In some alternative embodiments, the display device can be a touch screen. The electronic device also includes a communication interface for communication of the electronic device with other devices or communication networks.

[0052] The embodiments of the present application also provide a computer readable storage medium, and the above-mentioned method according to the embodiments of the present application can be implemented in hardware, firmware, or recorded in a storage medium, or stored in a remote storage medium or a non-transitory machine readable storage medium and downloaded from a network and stored in a local storage medium, so that the method described herein can be processed by such software on a storage medium using a general purpose computer, a special purpose processor, or programmable or special purpose hardware.

[0053] The storage medium can be a disk, an optical disk, a read-only memory, a random access memory, a flash memory, a hard disk, or a solid state disk, etc. Further, the storage medium can also include a combination of the above-mentioned kinds of memory. It can be understood that the computer, the processor, the microprocessor controller, or the programmable hardware includes a storage component that can store or receive software or computer code, when the software or computer code is accessed and executed by the computer, the processor, or the hardware, the method shown in the above embodiments is implemented.

[0054] Embodiments of the present application can also provide a computer program product comprising computer program instructions, which, when executed by a processor, cause the processor to perform the steps of the above method. Wherein the computer program product can be written in any combination of one or more programming languages to perform the operations of the embodiments of the present disclosure, including object-oriented programming languages such as Java, C++, and conventional procedural programming languages such as "C" language or similar programming languages. The program code can be executed entirely on a user computing device, partially on a user device, as an independent software package, partially on a user computing device and partially on a remote computing device, or entirely on a remote computing device or server.

[0055] The above embodiments are only used to illustrate the technical solutions of the present application, but not limit them; although the above embodiments of the present application are described in detail, those skilled in the art should understand that the technical solutions recorded in the above embodiments can be modified, or some technical features can be replaced by equivalent ones; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A method for sand surface reinforcement based on microbial mineralization, characterized in that, The method comprises the following steps: Step 1: determining injection points on the sand land to be reinforced; Step 2: injecting a bacteria solution containing urease-producing bacteria into the surface of the sand land to be reinforced at the injection points; Step 3: injecting a cementation solution into the surface of the sand land to be reinforced at the injection points; the cementation solution comprises urea and calcium chloride.

2. The method for sand surface reinforcement based on microbial mineralization according to claim 1, characterized in that, In step 1, the injection points are distributed in a grid-like staggered manner on the sand land to be reinforced, and the distance between adjacent injection points is 30-50 cm.

3. The method for sand surface reinforcement based on microbial mineralization according to claim 1, characterized in that, In step 2, the urease-producing bacteria are Bacillus pasteurii, and the concentration of the urease-producing bacteria in the bacteria solution is controlled to be 0.8-1.2 OD600. Preferably, in step 2, the injection amount of the bacteria solution is 1.0-5.0 L.

4. The method for sand surface reinforcement based on microbial mineralization according to claim 1, characterized in that, In step 2, calcium chloride solution is first added to the injection points, and then the bacteria solution containing urease-producing bacteria is injected into the surface of the sand land to be reinforced at the injection points.

5. The method for sand surface reinforcement based on microbial mineralization according to claim 1, characterized in that, In step 3, the cementation solution comprises 0.3-0.8 mol / L CaCl2 and 0.3-0.8 mol / L urea. Preferably, in step 3, the injection amount of the cementation solution is 2.0-6.0 L. Preferably, in step 3, the cementation solution is injected into the surface of the sand land to be reinforced at the injection points after 12-20 hours of injecting the bacteria solution.

6. The method for sand surface reinforcement based on microbial mineralization according to claim 1, characterized in that, Further comprising step 4: covering the surface layer of the sand land to be reinforced with a breathable sunshade material and spraying water to maintain the water content of the sand land to be reinforced at 15%-25%.

7. A sand surface reinforcement system based on microbial mineralization, characterized in that, The method comprises: an injector for inserting into the injection points on the sand land to be reinforced; a bacteria solution injection device for injecting the bacteria solution containing urease-producing bacteria into the surface of the sand land to be reinforced at the injection points; a cementation solution injection device for injecting the cementation solution into the surface of the sand land to be reinforced at the injection points; a control device for controlling the injector, the bacteria solution injection device, and the cementation solution injection device to perform the method for reinforcing the surface of the sand land based on microbial mineralization according to any one of claims 1-6.

8. The microbial-mineralization-based sand dune surface stabilization system according to claim 7, characterized in that, Further comprising a shading and humidifying device for covering the surface layer of the sand land to be reinforced with a breathable sunshade material and spraying water.

9. The microbial-mineralization-based sand dune surface stabilization system of claim 7, wherein, The bacteria solution injection device comprises a bacteria solution tank connected with a bacteria solution injection pump; the bacteria solution injection pump is used to pump the bacteria solution in the bacteria solution tank into the injector; The cementation solution injection device comprises a cementation solution tank connected with a cementation solution injection pump; the cementation solution injection pump is used to pump the cementation solution in the cementation solution tank into the injector.

10. An electronic device, comprising: The device comprises a memory and a processor connected with each other; The memory stores computer instructions, and the processor executes the computer instructions to perform the method for reinforcing the surface of the sand land based on microbial mineralization according to any one of claims 1-6.

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