Sandy soil reinforcement test device based on microbial mineralization technology

Abstract

The embodiment of the invention provides a sandy soil reinforcement test device based on a microbial mineralization technology, which comprises a cementing liquid providing module used for providing a cementing liquid and mixing preset gas suitable for microorganism survival; the microorganism mineralization reaction module is connected with the cementing liquid supply module and used for storing the sandy soil, microorganisms and cementing liquid and mixing the sandy soil, the microorganisms and the cementing liquid to obtain a mixture, so that the microorganisms generate mineralization reaction on the sandy soil; the monitoring module is connected with the microorganism mineralization reaction module and is used for monitoring the pH value and the dissolved oxygen content of the mixture; the temperature control module is connected with the microorganism mineralization reaction module and is used for controlling the temperature in the microorganism mineralization reaction module. According to the device disclosed by the invention, microorganisms attached to gravels and the cementing liquid are uniformly mixed through stirring, and the dissolved oxygen concentration of the cementing liquid is adjusted, so that a more suitable habitat is provided for different types of microorganisms. The pH and dissolved oxygen data obtained by the monitoring module can provide a theoretical basis for the application of the microbial mineralization technology in practical engineering.

Description

Technical Field

[0001] The invention relates to the technical field of soil reinforcement, in particular to a sand reinforcement test device based on microbial mineralization technology. Background Art

[0002] Sand reinforcement based on microbial mineralization technology is an innovative bioengineering technology that uses the metabolism of microorganisms to convert soluble minerals in the soil into insoluble mineral deposits, such as calcium carbonate and silicates, thereby improving the strength and durability of the soil. Compared with traditional physical or chemical reinforcement methods, this technology has the advantages of being environmentally friendly, cost-effective and sustainable. Currently, the commonly used methods include injection, spraying, immersion, etc.

[0003] In large-area or deep soil treatment, it is difficult to ensure uniform distribution of microbial liquid and cementing liquid in the entire soil profile by injection method. This may lead to better mineralization effect in some areas and poor effect in other areas, affecting the overall reinforcement effect.

[0004] The spraying method mainly acts on the surface of the soil, and it is difficult to ensure that the bacterial solution and the cementing solution penetrate deep into the soil. The effect is limited when treating deep reinforced soil. During the spraying process, environmental conditions such as wind speed, humidity and temperature may affect the spraying effect. For example, strong winds may cause uneven dispersion of the bacterial solution and the cementing solution, and too high or too low temperatures may affect the activity and mineralization effect of microorganisms.

[0005] The immersion method usually requires a long immersion process to ensure that the microorganisms and the cementing fluid fully penetrate and react. In addition, the mineralization process involves the use of a large amount of cementing fluid to completely immerse the sand sample. For large-scale soil treatment projects, this will result in high material costs and resource consumption. Summary of the invention

[0006] In view of the above problems, an embodiment of the present invention is proposed to provide a sand reinforcement test device based on microbial mineralization technology that overcomes the above problems or at least partially solves the above problems.

[0007] In order to solve the above problems, the embodiment of the present invention discloses a sand reinforcement test device based on microbial mineralization technology, comprising:

[0008] A cementing liquid providing module, used for providing a cementing liquid and mixing a preset gas suitable for the survival of microorganisms into the cementing liquid;

[0009] A microbial mineralization reaction module is connected to the cementing liquid providing module, and is used to store sand, microorganisms, and the cementing liquid obtained from the cementing liquid providing module, and mix the sand, the microorganisms, and the cementing liquid to obtain a mixture, so that the microorganisms produce a mineralization reaction on the sand;

[0010] A monitoring module, connected to the microbial mineralization reaction module, for monitoring preset parameters of the mixture; the preset parameters include pH value and dissolved oxygen content;

[0011] The temperature control module is connected to the microbial mineralization reaction module and is used to control the temperature inside the microbial mineralization reaction module.

[0012] Optionally, the bonding liquid providing module includes:

[0013] A liquid inlet tank, used for storing the cementing liquid;

[0014] A gas tank connected to the liquid inlet tank via a conduit, used to provide a preset gas suitable for the survival of microorganisms; a gas collecting bag connected to the liquid inlet tank via a conduit, used to collect the remaining gas in the liquid inlet tank that is not mixed into the cementing liquid;

[0015] a first gas washing bottle connected to the conduit between the gas collecting bag and the liquid inlet tank, and used to absorb water-soluble gas from the liquid inlet tank through the water stored in the first gas washing bottle;

[0016] A first pump, one end of which is connected to the liquid inlet tank through a pump tube, and the other end of which is connected to the microbial mineralization reaction module through a pump tube, is used to pump the cementing liquid mixed with the preset gas in the liquid inlet tank into the microbial mineralization reaction module.

[0017] Optionally, the microbial mineralization reaction module comprises:

[0018] An intermittent reactor, the intermittent reactor comprising a top cover and a bottom cover, wherein the top cover has an air outlet; and is used to store sand, microorganisms, and the cementing liquid obtained from the cementing liquid providing module;

[0019] a second gas washing bottle, connected to the intermittent reactor from the gas outlet of the top cover through a conduit, and used for absorbing water-soluble gas from the intermittent reactor through water stored in the gas washing bottle;

[0020] A stirrer, used for mixing the sand, the microorganisms and the cementing liquid stored in the intermittent reactor to obtain a mixture;

[0021] A liquid outlet box, used for collecting the remaining cementing liquid in the intermittent reactor;

[0022] A second pump has one end connected to the intermittent reactor through a pump tube and the other end connected to the liquid outlet tank through a pump tube, and is used to pump the remaining cementing liquid in the intermittent reactor into the liquid outlet tank.

[0023] Optionally, the monitoring module includes:

[0024] A pH probe, used to collect the pH value of the mixture;

[0025] A dissolved oxygen probe, used for collecting the dissolved oxygen content of the mixture;

[0026] A monitor, one end of which is connected to the pH probe and the other end of which is connected to the dissolved oxygen probe, is used to monitor the pH value and dissolved oxygen content of the mixture.

[0027] Optionally, the temperature control module includes:

[0028] A water bath interlayer, wrapped around the outside of the intermittent reactor, storing constant temperature water inside to keep the intermittent reactor at a constant temperature;

[0029] A constant temperature water bath is connected to the water bath interlayer through a conduit and is used to provide constant temperature water to the water bath interlayer.

[0030] Optionally, the bonding liquid providing module further includes:

[0031] an aeration head, disposed at the end of a conduit connected from the gas tank to the liquid inlet tank, for aerating a preset gas from the gas tank into the liquid inlet tank;

[0032] A three-way valve, wherein the gas collecting bag and the gas washing bottle are connected to both ends of the three-way valve through a silicone tube, and the other end of the three-way valve is connected to the top of the liquid inlet tank, so as to control the gas flow rate flowing in the conduits in three directions.

[0033] Optionally, the preset gas includes nitrogen or oxygen, the nitrogen is used to maintain an environment suitable for the survival of microorganisms, and the oxygen is used to supplement the dissolved oxygen content in the cementing fluid when it is insufficient.

[0034] Optionally, the binder liquid components in the liquid inlet box include calcium chloride and urea; or calcium nitrate and sodium acetate.

[0035] Optionally, the agitator includes a motor with adjustable speed, a stirring paddle and a coupling.

[0036] Optionally, one end of the first pump is connected to the liquid inlet box through a pump tube, and the other end is connected to the bottom cover of the intermittent reactor through a pump tube to pump the cementing liquid into the intermittent reactor;

[0037] One end of the second pump passes through the top cover of the intermittent reactor through a pump tube and is inserted into the intermittent reactor at a corresponding height, and the other end is connected to the liquid outlet box through a pump tube to pump the remaining binder liquid in the intermittent reactor into the liquid outlet box.

[0038] Optionally, the dissolved oxygen concentration of the cementing liquid provided by the cementing liquid providing module is compatible with the microorganisms.

[0039] Optionally, the pH probe and the dissolved oxygen probe are made of acid-resistant, alkali-resistant and corrosion-resistant materials.

[0040] Optionally, the bonding liquid providing module further includes a pressure reducing valve, which is disposed in a conduit connecting the liquid inlet box and the gas tank, and is used to control the flow rate of a preset gas transmitted from the gas tank to the liquid inlet box through the conduit.

[0041] Optionally, the cementing liquid providing module further includes: a check valve, which is arranged on the pump pipe between the first pump and the microbial mineralization reaction module and is used to control the cementing liquid first pumped into the microbial mineralization reaction module.

[0042] Optionally, an output valve is arranged on the pump pipe between the intermittent reactor and the second pump, and is used to control the binder liquid pumped out from the intermittent reactor.

[0043] The embodiments of the present invention include the following advantages:

[0044] The present invention provides a sand reinforcement test device based on microbial mineralization technology, including: a cementing liquid providing module, used to provide a cementing liquid and mix it with a preset gas suitable for the survival of microorganisms; a microbial mineralization reaction module, connected to the cementing liquid providing module, used to store sand, microorganisms and the cementing liquid obtained from the cementing liquid providing module, and stir and mix to obtain a mixture, so that the microorganisms produce a mineralization reaction on the sand; a monitoring module, connected to the microbial mineralization reaction module, used to monitor the pH value and dissolved oxygen content of the mixture; a temperature control module is connected to the microbial mineralization reaction module, used to control the temperature inside the microbial mineralization reaction module. The device of the present invention mixes the microorganisms attached to the gravel and the cementing liquid evenly by stirring, and adjusts the dissolved oxygen concentration of the cementing liquid to provide a more suitable habitat for different types of microorganisms. The pH and dissolved oxygen data obtained by the online monitor will provide a theoretical basis for the application of microbial mineralization technology in practical engineering. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 It is a structural block diagram of a sand reinforcement test device based on microbial mineralization technology provided by an embodiment of the present invention;

[0046] Figure 2It is a structural schematic diagram of another sand reinforcement test device based on microbial mineralization technology provided in an embodiment of the present invention.

[0047] Description of reference numerals:

[0048] 10-cementing liquid supply module, 11-microorganism mineralization reaction module, 12-monitoring module, 13-temperature control module, 101-liquid inlet box, 102-gas tank, 103-pressure reducing valve, 104-gas collecting bag, 105-first gas washing bottle, 106-first pump, 107-check valve, 108-aeration head, 109-three-way valve, 111-intermittent reactor, 1111-top cover, 1112-bottom cover, 112-second gas washing bottle, 113-agitator, 1131-motor, 1132-coupling shaft, 1133-stirring paddle, 114-liquid outlet box, 115-second pump, 116-output valve, 121-pH probe, 122-dissolved oxygen probe, 123-monitoring instrument, 131-water bath interlayer, 132-constant temperature water bath. DETAILED DESCRIPTION

[0049] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the present invention is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0050] In sand reinforcement, MICP (Microbially Induced Calcite Precipitation, MICP for short, a technology that uses microbial metabolic activity to promote calcium carbonate precipitation) technology has been successfully applied to dam anti-seepage treatment, road foundation reinforcement, desertification prevention and other fields. Compared with traditional materials such as cement, the microbial liquid used in MICP technology has low viscosity and low pressure required for grouting, which is more suitable for long-distance and large-area reinforcement operations and reduces the burden on the environment. The microbial reinforcement process is a naturally occurring biochemical reaction that reduces energy consumption and pollutant emissions, and meets the requirements of green buildings and sustainable development.

[0051] Specific microorganisms (such as urea-decomposing bacteria such as Bacillus pasteurianus) can decompose urea into ammonia and carbon dioxide under appropriate conditions. These microorganisms can also catalyze the reaction of carbon dioxide and water to produce carbonic acid, which further reacts with calcium ions in the environment to produce insoluble calcium carbonate precipitates. Calcium carbonate precipitates act as natural "binders" to form bridges between sand particles, significantly improving the overall strength and stability of the soil and reducing permeability. The type of microorganisms, nutrient solution concentration, calcium source supply, pH value, temperature, and initial conditions of sand are all key factors affecting the effect of MICP. Adjusting the concentration of the binder can control the size and distribution of calcium carbonate crystals, thereby affecting the curing effect.

[0052] With the deepening of understanding of the mechanism of microbial mineralization and the continuous advancement of engineering technology, the application of MICP technology in the reinforcement of sand and other types of soil will become more extensive and efficient. Sand reinforcement based on microbial mineralization technology is a field full of potential. It not only provides new ideas for solving reinforcement problems in civil engineering, but also contributes to environmental protection and sustainable development.

[0053] One of the core concepts of the embodiments of the present invention is that by mechanical stirring, the bacterial solution and the binder are fully mixed with the soil sample, which can ensure the uniform distribution of microorganisms and the binder in the soil and improve the uniformity and effect of the mineralization reaction. The dissolved oxygen content in deep soil is low, and the activity of aerobic bacteria is inhibited, which may lead to uneven overall consolidation. By adjusting the dissolved oxygen concentration of the binder, a more suitable habitat is provided for different types of microorganisms. Explore the good sample-anaerobic multi-microorganism mineralization system to achieve deeper soil reinforcement. Processing a large amount of soil samples in a relatively short period of time is particularly suitable for small and medium-sized soil improvement projects and improves work efficiency.

[0054] Reference Figure 1 , shows a structural block diagram of a sand reinforcement test device based on microbial mineralization technology provided by an embodiment of the present invention, which may specifically include the following modules:

[0055] The cementing liquid providing module 10 is used to provide a cementing liquid and mix a preset gas suitable for the survival of microorganisms into the cementing liquid.

[0056] In microbial mineralization technology, cementing fluid (also called mineralizing fluid or inducing fluid) plays a vital role. It is a carefully formulated solution that contains the nutrients and chemical components required for microbial growth, which is used to stimulate the mineralization reaction of microorganisms, thereby forming mineral precipitation in soil, rock or other materials and enhancing their physical and mechanical properties. The cementing fluid contains nutrients necessary for microbial growth, such as carbon source, nitrogen source, phosphorus source, trace elements, etc. These components serve as energy sources for microorganisms and support their metabolic activities. The components in the cementing fluid can adjust environmental conditions such as the pH value and redox potential of the soil or solution, create a microenvironment suitable for the growth of specific microorganisms, and promote the occurrence of mineralization reactions. The chemical components in the cementing fluid can directly participate in or catalyze the mineralization reaction induced by microorganisms, such as the precipitation of calcium carbonate, and promote the formation of minerals by increasing the concentration of calcium ions and carbonate ions. In some applications, the cementing fluid is used as a carrier to inoculate microorganisms into the target area to ensure that the microorganisms can be evenly distributed and start their mineralization. By adjusting the formula of the cementing fluid, such as changing the proportion of nutrients, pH value, buffering capacity, etc., the rate of microbial mineralization reaction and the type of mineral ultimately formed can be controlled to achieve the best reinforcement effect.

[0057] The microbial mineralization reaction module 11 is connected to the cementing liquid providing module, and is used to store sand, microorganisms and the cementing liquid obtained from the cementing liquid providing module, and mix the sand, the microorganisms and the cementing liquid to obtain a mixture so that the microorganisms produce a mineralization reaction on the sand.

[0058] Byproducts (such as ammonia) produced during microbial metabolism change the chemical environment of the soil, promote the reaction of calcium ions and carbonate ions in the soil solution, and form insoluble calcium carbonate precipitates. These precipitates act as "cementing agents" to fill in between soil particles, enhancing the cohesion and strength of the soil. Over time, mineral precipitation caused by microbial mineralization reactions gradually accumulates, improving the soil structure and its physical and mechanical properties, such as increased compressive strength and reduced permeability, thereby improving the stability and bearing capacity of the soil.

[0059] The traditional injection method uses a peristaltic pump to transport bacterial solution and cementing solution. The use of a peristaltic pump can accurately control the liquid flow rate and ensure the repeatability and accuracy of the experiment. After the cementing solution is mixed with the bacterial solution, the metabolic activity of the microorganisms causes a mineralization reaction, and the loose sand particles gradually cement into a whole with a certain strength. However, in large-scale or deep soil treatment, it is difficult to ensure the uniform distribution of microbial bacterial solution and cementing solution in the entire soil profile through the injection method, which may lead to better mineralization effects in some areas and poorer effects in other areas, affecting the overall reinforcement effect.

[0060] The microbial mineralization reaction module of the present invention can evenly mix the mixed strains of urease-producing bacteria cultured and purified in advance in the laboratory, the sand to be mineralized, and the cementing liquid with suitable pH value and dissolved oxygen content provided by the cementing liquid providing module, so as to make the mineralization reaction of the microorganisms more complete.

[0061] The monitoring module 12 is connected to the microbial mineralization reaction module and is used to monitor the preset parameters of the mixture; the preset parameters include pH value and dissolved oxygen content.

[0062] The microbial mineralization process is affected by a variety of environmental factors, including temperature, pH, oxygen supply, etc. Small-scale field trials or laboratory simulations are usually required to evaluate the reinforcement effect of microbial mineralization on a specific soil. The pH probe and dissolved oxygen probe are connected to the monitor for continuous monitoring to verify the reinforcement effect and adjust the process parameters. By precisely controlling these conditions, the mineralization rate and mineral formation can be optimized, improving the reinforcement effect.

[0063] The temperature control module 13 is connected to the microbial mineralization reaction module and is used to control the temperature inside the microbial mineralization reaction module.

[0064] The main functions of the temperature control module include: temperature regulation, the temperature control module can accurately control the temperature inside the reactor to keep it within a specific range; heating and cooling, when heating is required, the temperature control module can increase the temperature inside the reactor through the heating element, and when cooling is required, the temperature is lowered through the cooling system; temperature monitoring, the temperature control module is usually equipped with a temperature sensor, which can monitor the temperature changes in the reactor in real time and feed the data back to the control system; automatic control, modern temperature control modules usually have an automatic adjustment function, which can automatically adjust the heating or cooling power according to the preset temperature setting value to maintain a constant temperature; safety assurance, the temperature control module also includes an over-temperature protection mechanism to prevent safety hazards caused by excessive temperature.

[0065] In the microbial mineralization device, the design and selection of the temperature control module depends on many factors, including: temperature range, according to the type of microorganisms used and the reaction conditions, determine the temperature range that the temperature control module needs to cover; accuracy requirements, different microorganisms have different sensitivities to temperature, so it is necessary to select a temperature control module with appropriate accuracy according to experimental requirements; reactor size, the power and design of the temperature control module need to match the size and volume of the reactor to ensure the uniformity and effectiveness of temperature control; energy consumption and cost, when selecting a temperature control module, its energy consumption and operating cost must also be considered to ensure economic benefits.

[0066] The present invention provides a sand reinforcement test device based on microbial mineralization technology. The device consists of a cementing liquid providing module, a microbial mineralization reaction module, a monitoring module and a temperature control module. The cementing liquid providing module can determine aerobic or anaerobic conditions according to the needs of microorganisms; the microbial mineralization reaction module has a stirring device, which can fully mix the microorganisms with the cementing liquid; the monitoring module is composed of a pH probe and a dissolved oxygen probe to monitor data parameters in time; the temperature control module can maintain the temperature required for the reaction for a long time. The device can maintain the high activity of microorganisms and avoid problems such as low mineralization efficiency due to pore blockage. The device is simple in layout and flexible in operation. The bacterial solution and cementing liquid used are harmless to the environment and optimize the microbial mineralization technology. At the same time, the obtained data parameters can provide a theoretical basis for the application of soil reinforcement in practical engineering.

[0067] Reference Figure 2 , shows a schematic structural diagram of another sand reinforcement test device based on microbial mineralization technology provided by an embodiment of the present invention, wherein:

[0068] The cementing liquid providing module 10 comprises:

[0069] A liquid inlet tank 101, used for storing the cementing liquid;

[0070] The liquid inlet box 101 is a closed container with three openings, namely, an air inlet, an air outlet and a liquid outlet; the cementing liquid contained therein is a mixture of calcium chloride and urea in a normal mineralization reaction, and is a mixture of calcium nitrate and sodium acetate in a nitrification reaction. The specific composition of the cementing liquid can be carefully configured according to the nutrients and chemicals required for the microbial growth reaction.

[0071] The gas tank 102 is connected to the liquid inlet box 101 through a conduit and is used to provide a preset gas suitable for the survival of microorganisms;

[0072] In most cases, the gas tank 102 is used as a nitrogen tank. Regardless of whether it is anaerobic microorganisms or aerobic microorganisms, in special circumstances where the oxygen content in normal air is still insufficient, oxygen can be added to the gas tank to supplement the dissolved oxygen content of the cementing liquid. The cementing liquid providing module provides a dissolved oxygen concentration that is compatible with the microorganisms.

[0073] The pressure reducing valve 103 is disposed in a conduit connecting the liquid inlet box 101 and the gas tank 102 , and is used to control the flow rate of a preset gas transmitted from the gas tank 102 to the liquid inlet box 101 through the conduit.

[0074] The gas collecting bag 104 is connected to the liquid inlet box 101 through a conduit and is used to collect the remaining gas in the liquid inlet box 101 that is not mixed with the cementing liquid;

[0075] After the reaction starts, the nitrogen or oxygen lost in the water tank can also be replenished to maintain an anaerobic or aerobic environment for a long time.

[0076] The first gas washing bottle 105 is connected to the conduit between the gas collecting bag 104 and the liquid inlet tank 101, and is used to absorb the water-soluble gas from the liquid inlet tank 101 through the water stored in the first gas washing bottle 105;

[0077] The specific application of the gas washing bottle is very wide. Different absorbents can be selected according to the types of impurities to be removed, for example: using alkaline solutions such as sodium hydroxide solution to absorb acidic gases such as hydrogen chloride; using copper sulfate solution to absorb ammonia; using concentrated sulfuric acid to dry the gas to remove the water therein, etc. In this embodiment, the first gas washing bottle 105 is mainly filled with water, which is used to absorb excess water-soluble gas to balance the pressure in the liquid inlet box 101.

[0078] A first pump 106, one end of which is connected to the liquid inlet tank 101 through a pump tube, and the other end of which is connected to the microbial mineralization reaction module through a pump tube, and is used to pump the cementing liquid mixed with the preset gas in the liquid inlet tank 101 into the microbial mineralization reaction module;

[0079] The first pump 106 is a peristaltic pump, which is also called a hose pump or a roller pump. It is a positive displacement pump that is particularly suitable for accurate, continuous and adjustable flow rate liquid transmission. Its core working principle is to promote the flow of liquid by squeezing a section of elastic hose, rather than relying on the traditional piston or blade mechanism. The advantages of peristaltic pumps include: high flow control accuracy, suitable for precise transmission of trace to large flow rates; because the liquid only contacts the hose, it is very suitable for conveying sensitive liquids, such as liquid medicine, food concentrate, etc., and is easy to clean and disinfect; it can be self-priming and can extract liquid from the container without the need for additional suction equipment; it can handle almost any liquid of any nature, including liquids containing particles, high viscosity, strong corrosiveness or volatile liquids; only the hose needs to be replaced regularly, and the maintenance cost is low. In this embodiment, the cementing liquid pumped into the intermittent reactor can be accurately controlled to accurately control the mineralization reaction.

[0080] The check valve 107 is arranged on the pump pipe between the first pump 106 and the microbial mineralization reaction module, and is used to control the cementing liquid pumped into the microbial mineralization reaction module.

[0081] an aeration head 108, disposed at the end of a conduit connected from the gas tank 102 to the liquid inlet tank 101, for aerating a preset gas from the gas tank 102 into the liquid inlet tank 101;

[0082] Aeration head is a key component in sewage treatment and water treatment process. It is mainly used to fill air into sewage treatment pool or biochemical reaction pool to provide oxygen required for microbial growth and promote the oxidation and decomposition of organic matter in biological treatment process. Aeration not only increases the dissolved oxygen in water, but also stirs the water, enhances the contact between pollutants and microorganisms, and improves treatment efficiency.

[0083] The three-way valve 109, the gas collecting bag 104 and the first gas washing bottle 105 are connected to both ends of the three-way valve 109 through silicone tubes, and the other end of the three-way valve 109 is connected to the top of the liquid inlet box 101 to control the gas flow in the conduits in three directions.

[0084] The microbial mineralization reaction module 11 comprises:

[0085] The intermittent reactor 111 comprises a top cover 1111 and a bottom cover 1112, wherein the top cover 1111 has an air outlet; the intermittent reactor 111 is used to store sand, microorganisms and a binder obtained from a binder providing module.

[0086] This is the core part of the device, which is used to cultivate specific microbial strains, such as urea-decomposing bacteria, sulfur-oxidizing bacteria, etc. These microorganisms can promote the precipitation of minerals in the soil. The microorganisms in this embodiment are mainly mixed strains such as urease-producing bacteria after laboratory culture and purification.

[0087] The second scrubbing bottle 112 is connected to the intermittent reactor 111 through a conduit from the gas outlet of the top cover 1111 , and is used to absorb water-soluble gas from the intermittent reactor 111 through the water stored in the second scrubbing bottle 112 .

[0088] The agitator 113 is used to mix the sand, microorganisms and cementing liquid stored in the intermittent reactor 111 to obtain a mixture;

[0089] The stirrer 113 also includes a motor 1131 with adjustable speed, a stainless steel coupling 1132 and a stirring paddle 1133;

[0090] By stirring the reaction medium, the agitator can evenly distribute microorganisms, nutrients and chemical reagents in the solution, ensuring that all components can effectively participate in the mineralization process; through stirring, the contact area between the reaction medium and solid particles can be increased, promoting full contact between microorganisms and the surface of soil particles, thereby improving mineralization efficiency; the agitator can help control the temperature, pH value and other conditions of the reaction medium to ensure that the microorganisms are in the best working environment; stirring can accelerate the mass transfer process in the reaction medium, allowing the substances produced by microbial metabolism to diffuse to various parts of the reaction medium more quickly, which is conducive to the mineralization reaction; stirring helps to avoid stratification of sediment in the reaction medium and ensure that the solution remains uniform and consistent, which is very important for maintaining the continuity and consistency of the reaction; through effective stirring, the speed of microbial mineralization reaction can be accelerated, the processing time can be shortened, and the overall efficiency can be improved.

[0091] The liquid outlet box 114 is used to collect the remaining cementing liquid in the intermittent reactor 111;

[0092] It is mainly used to collect and store the solution after the microbial mineralization reaction. This solution usually contains microbial metabolites, incompletely reacted raw materials, and possible mineral precipitates. The solution discharged from the reactor is collected to facilitate subsequent processing or analysis. The liquid outlet box is usually equipped with monitoring instruments and sampling ports to facilitate regular inspection of the chemical composition, pH value, turbidity and other parameters of the solution, as well as to collect samples for detailed analysis. In some cases, the solution in the liquid outlet box will be reintroduced into the microbial mineralization reactor to improve the mineralization efficiency or ensure that the microorganisms have enough nutrients.

[0093] A second pump 115, one end of which is connected to the intermittent reactor 111 through a pump tube, and the other end of which is connected to the liquid outlet box 114 through a pump tube, and is used to pump the remaining cementing liquid in the intermittent reactor 111 into the liquid outlet box 114;

[0094] The output valve 116 is arranged on the pump pipe between the intermittent reactor 111 and the second pump 115, and is used to control the cementing liquid pumped out from the intermittent reactor 111.

[0095] The liquid outlet box 114 is equipped with a second pump 115 and an output valve 116 to adjust the inflow and outflow rates of the solution to ensure the stable operation of the entire system and prevent the leakage of the solution in the event of overfilling or accidental leakage. In soil reinforcement or contaminated soil remediation projects, the liquid outlet box can help collect and process the solution containing mineral precipitation to evaluate the mineralization effect and recycle the precipitation.

[0096] The monitoring module 12 is connected to the microbial mineralization reaction module and is used to monitor preset parameters of the mixture; the preset parameters include pH value and dissolved oxygen content;

[0097] A pH probe 121, used for collecting the pH value of the mixture;

[0098] A dissolved oxygen probe 122, used for collecting the dissolved oxygen content of the mixture;

[0099] Monitoring dissolved oxygen levels in the reaction medium is essential for the mineralization reaction of aerobic microorganisms. Changes in dissolved oxygen levels can reflect the strength of microbial activity and whether aeration needs to be increased or other conditions need to be changed to maintain appropriate dissolved oxygen levels.

[0100] The monitor 123 has one end connected to the pH probe 121 and the other end connected to the dissolved oxygen probe 122, and is used to monitor the pH value and dissolved oxygen content of the mixture.

[0101] The monitoring probe is connected to the monitor, which can display the readings in real time and record the data for subsequent analysis. The pH probe and dissolved oxygen probe are made of acid and alkali resistant and corrosion resistant materials. Through these monitoring probes, operators can adjust the reaction conditions in time to optimize the effect of the microbial mineralization process.

[0102] The temperature control module 13 is connected to the microbial mineralization reaction module and is used to control the temperature inside the microbial mineralization reaction module.

[0103] A water bath interlayer 131 is wrapped around the outside of the batch reactor 111;

[0104] The constant temperature water bath 132 is connected to the water bath interlayer 131 through a conduit, and is used to provide constant temperature water to the water bath interlayer 131 so that the constant temperature water in the water bath interlayer 131 can maintain the constant temperature of the intermittent reactor 111.

[0105] Temperature is very important for the microbial mineralization process, as it directly affects the growth rate, metabolic activity and efficiency of the mineralization reaction of the microorganisms. In this embodiment, the batch reactor 111 is controlled to maintain a constant temperature by a water bath method, which can accurately control the temperature and has low energy consumption and operating costs.

[0106] In order to enable those skilled in the art to better understand the embodiments of the present invention, the embodiments of the present invention are described below by using a reaction process example:

[0107] The gas tank 102 is connected to the aeration head 108 through a pneumatic PU tube and placed in the liquid inlet tank 101. The pressure reducing valve 103 controls the flow of nitrogen from the gas tank 102 to the liquid inlet tank 101, and the calcium chloride and urea mixed liquid binder in the liquid inlet tank 101 is mixed with nitrogen. The excess nitrogen is controlled by the three-way valve 109 to enter the gas collecting bag 104. The liquid inlet tank 101 is a sealed container. The excess water-soluble gas (such as carbon dioxide, etc.) is discharged to the first washing bottle 105 through the conduit to maintain the pressure in the liquid inlet tank 101.

[0108] The first pump 106 pumps the cementing liquid with suitable pH value and dissolved oxygen content mixed in the liquid inlet tank 101 into the intermittent reactor 111 through the pump pipe and the check valve 107. The intermittent reactor 111 is pre-loaded with cultured and purified microorganisms and sand to be mineralized. After the cementing liquid is pumped in, the stirrer 113 is turned on to start stirring. The stirrer 113 is controlled by a motor 1131 with adjustable speed through a stainless steel coupling 1132 to control a stirring paddle 1133 to stir the cementing liquid, sand and microorganisms.

[0109] At the same time, the constant temperature water bath 132 is opened, in which constant temperature water is stored, and water is injected into the water bath interlayer 131 wrapped outside the intermittent reactor 111 through a PVC hose to maintain a constant temperature environment suitable for microbial reaction inside the intermittent reactor 111. The intermittent reactor 111 includes a water outlet top cover 1111 and a detachable bottom cover 1112, both of which are made of organic glass; the top cover 1111 has an air outlet, and the second washing bottle 112 is connected to the air outlet; the second washing bottle 112 is filled with water like the first washing bottle 105, which is used to absorb carbon dioxide and other gases generated in the intermittent reactor 111 to maintain the pressure in the intermittent reactor 111.

[0110] The pH probe 121 is placed in the middle of the left side of the batch reactor 111, and the dissolved oxygen probe 122 is placed in the middle of the right side of the batch reactor 111. The pH probe 121 and the dissolved oxygen probe 122 are connected to the external online monitor 123 through wires to jointly monitor the pH value and dissolved oxygen content of the sediment-water mixture in the batch reactor 111.

[0111] After the reaction is completed, the stirring is stopped to allow the sand to settle, and the pump tube is inserted into the intermittent reactor 111 to a corresponding height through the second pump 115 and the cementing liquid output valve 115, and the remaining cementing liquid is sucked out after the sand is settled and discharged into the liquid outlet box 114. The solidified sand settled in the intermittent reactor 111 can be taken out through the detachable bottom cover 1112.

[0112] In the description of the present invention, it should be understood that the terms "center", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0113] In addition, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0114] Although the preferred embodiments of the present invention have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the embodiments of the present invention.

[0115] Finally, it should be noted that, in this article, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" can explicitly or implicitly include one or more of the features. Relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that the process, method, article or terminal device including a series of elements includes not only those elements, but also other elements that are not explicitly listed, or also includes elements inherent to such process, method, article or terminal device. In the absence of more restrictions, the elements defined by the sentence "including one..." do not exclude the existence of other identical elements in the process, method, article or terminal device including the elements.

[0116] The above is a detailed introduction to a sand reinforcement test device based on microbial mineralization technology provided by the present invention. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for general technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A sand reinforcement test device based on microbial mineralization technology, characterized in that: include: A cementing liquid providing module, used for providing a cementing liquid and mixing a preset gas suitable for the survival of microorganisms into the cementing liquid; A microbial mineralization reaction module is connected to the cementing liquid providing module, and is used to store sand, microorganisms, and the cementing liquid obtained from the cementing liquid providing module, and mix the sand, the microorganisms, and the cementing liquid to obtain a mixture, so that the microorganisms produce a mineralization reaction on the sand; A monitoring module, connected to the microbial mineralization reaction module, for monitoring preset parameters of the mixture; the preset parameters include pH value and dissolved oxygen content; The temperature control module is connected to the microbial mineralization reaction module and is used to control the temperature inside the microbial mineralization reaction module.

2. The sand reinforcement test device based on microbial mineralization technology according to claim 1 is characterized in that: The cementing liquid providing module comprises: A liquid inlet tank, used for storing the cementing liquid; A gas tank, connected to the liquid inlet box through a conduit, for providing a preset gas suitable for the survival of microorganisms; A gas collecting bag, connected to the liquid inlet tank via a conduit, for collecting the remaining gas in the liquid inlet tank that is not mixed into the cementing liquid; a first gas washing bottle connected to the conduit between the gas collecting bag and the liquid inlet tank, and used to absorb water-soluble gas from the liquid inlet tank through the water stored in the first gas washing bottle; A first pump, one end of which is connected to the liquid inlet tank through a pump tube, and the other end of which is connected to the microbial mineralization reaction module through a pump tube, is used to pump the cementing liquid mixed with the preset gas in the liquid inlet tank into the microbial mineralization reaction module.

3. The sand reinforcement test device based on microbial mineralization technology according to claim 2 is characterized in that: The microbial mineralization reaction module comprises: An intermittent reactor, the intermittent reactor comprising a top cover and a bottom cover, wherein the top cover has an air outlet; and is used to store sand, microorganisms, and the cementing liquid obtained from the cementing liquid providing module; a second gas washing bottle, connected to the intermittent reactor from the gas outlet of the top cover through a conduit, and used for absorbing water-soluble gas from the intermittent reactor through water stored in the gas washing bottle; A stirrer, used for mixing the sand, the microorganisms and the cementing liquid stored in the intermittent reactor to obtain a mixture; A liquid outlet box, used for collecting the remaining cementing liquid in the intermittent reactor; A second pump has one end connected to the intermittent reactor through a pump tube and the other end connected to the liquid outlet tank through a pump tube, and is used to pump the remaining cementing liquid in the intermittent reactor into the liquid outlet tank.

4. The sand reinforcement test device based on microbial mineralization technology according to claim 1 is characterized in that: The monitoring module comprises: A pH probe, used to collect the pH value of the mixture; A dissolved oxygen probe, used for collecting the dissolved oxygen content of the mixture; A monitor, one end of which is connected to the pH probe and the other end of which is connected to the dissolved oxygen probe, is used to monitor the pH value and dissolved oxygen content of the mixture.

5. The sand reinforcement test device based on microbial mineralization technology according to claim 3 is characterized in that: The temperature control module comprises: A water bath interlayer, wrapped around the outside of the intermittent reactor, storing constant temperature water inside to keep the intermittent reactor at a constant temperature; A constant temperature water bath is connected to the water bath interlayer through a conduit and is used to provide constant temperature water to the water bath interlayer.

6. The sand reinforcement test device based on microbial mineralization technology according to claim 2 is characterized in that: The cementing liquid providing module also includes: an aeration head, disposed at the end of a conduit connected from the gas tank to the liquid inlet tank, for aerating a preset gas from the gas tank into the liquid inlet tank; A three-way valve, wherein the gas collecting bag and the gas washing bottle are connected to both ends of the three-way valve through a silicone tube, and the other end of the three-way valve is connected to the top of the liquid inlet tank, so as to control the gas flow rate flowing in the conduits in three directions.

7. The sand reinforcement test device based on microbial mineralization technology according to claim 2 is characterized in that: The preset gas includes nitrogen or oxygen. Nitrogen is used to maintain an environment suitable for the survival of microorganisms, and oxygen is used to supplement the dissolved oxygen content in the cementing fluid when it is insufficient.

8. The sand reinforcement test device based on microbial mineralization technology according to claim 2 is characterized in that: The components of the cementing liquid in the liquid inlet box include calcium chloride and urea; or calcium nitrate and sodium acetate.

9. The sand reinforcement test device based on microbial mineralization technology according to claim 3 is characterized in that: The stirrer comprises a motor with adjustable speed, a stirring paddle and a coupling.

10. The sand reinforcement test device based on microbial mineralization technology according to claim 3 is characterized in that: One end of the first pump is connected to the liquid inlet box through a pump pipe, and the other end is connected to the bottom cover of the intermittent reactor through a pump pipe to pump the cementing liquid into the intermittent reactor; One end of the second pump passes through the top cover of the intermittent reactor through a pump tube and is inserted into the intermittent reactor at a corresponding height, and the other end is connected to the liquid outlet box through a pump tube to pump the remaining binder liquid in the intermittent reactor into the liquid outlet box.

11. The sand reinforcement test device based on microbial mineralization technology according to claim 1 is characterized in that: The dissolved oxygen concentration of the cementing liquid provided by the cementing liquid providing module is compatible with the microorganisms.

12. The sand reinforcement test device based on microbial mineralization technology according to claim 4 is characterized in that: The pH probe and the dissolved oxygen probe are made of acid-resistant, alkali-resistant and corrosion-resistant materials.

13. The sand reinforcement test device based on microbial mineralization technology according to claim 2 is characterized in that: The cementing liquid providing module also includes: The pressure reducing valve is arranged in the conduit connecting the liquid inlet box and the gas tank, and is used to control the flow rate of the preset gas transmitted from the gas tank to the liquid inlet box through the conduit.

14. The sand reinforcement test device based on microbial mineralization technology according to claim 2 is characterized in that: The cementing liquid providing module also includes: The check valve is arranged on the pump pipe between the first pump and the microbial mineralization reaction module, and is used to control the cementing liquid first pumped into the microbial mineralization reaction module.

15. The sand reinforcement test device based on microbial mineralization technology according to claim 3 is characterized in that: The microbial mineralization reaction module also includes: The output valve is arranged on the pump pipe between the intermittent reactor and the second pump, and is used to control the cementing liquid pumped out from the intermittent reactor.

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