An in-situ fixation method for chaff suction flow river and lake bottom sediment

Abstract

A method for in-situ fixation of river and lake sediments using a suction dredging system involves suctioning river and lake sediments into a sediment preparation device using a sediment preparation system. The sediments are then further treated through chemical dosing, oxygenation, flocculent biological culture, and dewatering to obtain sediment preparation. Next, the sediments are suctioned into a centrifugal sediment preparation device using a centrifugal sediment preparation system. After chemical dosing, oxygenation, and an initial centrifugation process, initial centrifuged sediment is obtained. Sediment preparation is then added to this initial centrifuged sediment, and centrifugation and drainage are performed to prepare centrifugal sediment blanks. Finally, a second suction device creates multiple pits in the river and lake sediments below the dredging baseline. The prepared centrifugal sediment blanks are then buried in these pits using a sediment discharge device, effectively fixing heavy metals. This method for in-situ fixation of river and lake sediments enhances the self-repairing ability of the centrifugal sediment blanks, effectively prevents contaminated sediments from polluting overlying water, reduces the difficulty of in-situ remediation of river and lake sediments, and saves economic costs.

Description

Technical Field

[0001] This invention relates to the field of water environment restoration and management technology, and in particular to an in-situ fixation method for river and lake bottom sediments in a chaff suction flow state. Background Technology

[0002] In the process of river and lake pollution control, sediment pollution remediation is one of the main challenges and a prevalent environmental problem. Due to the dynamic balance between absorption and release between water and sediment, when water bodies suffer severe external pollution, some pollutants can enter the sediment through sedimentation and adsorption. Once the external pollution is controlled, various organic and inorganic pollutants accumulated in the sediment re-enter the overlying water through physical, chemical, and biological exchanges, thus causing secondary pollution. To remove sediment pollution, sediment dredging is commonly used.

[0003] However, while dredging effectively reduces endogenous pollution and improves river and lake water quality, it involves a large amount of engineering work and excessive removal of sediment, potentially dislodging large amounts of benthic organisms and aquatic plants, thus disrupting the original ecosystem of rivers and lakes. Furthermore, improper handling during dredging can lead to secondary pollution from heavy metals and other harmful substances in the silt.

[0004] Currently, commonly used methods for dredging river and lake bottom sediments mainly include dry dredging and dredging with water. Dry dredging involves completely draining the water from the river or lake and then using dredging machinery such as bulldozers or scrapers to remove polluted bottom sediment, thereby reducing pollution. However, dry dredging is limited to smaller river and lake basins and is not suitable for large or medium-sized basins. Furthermore, the dewatering process in this method can have significant negative impacts on production and daily life in the surrounding areas. Dredging with water involves using newer machinery to extract sludge, nutrients, and harmful substances from the bottom of rivers and lakes without draining or clearing the water. While dredging with water can purify the underwater environment of rivers and lakes and block pollution sources, it places high demands on dredgers, resulting in high dredging costs.

[0005] The two dredging methods mentioned above are difficult and costly for the in-situ restoration of existing river and lake bottom sediments. There is an urgent need for an in-situ fixation method for river and lake bottom sediments that is easier and less costly to restore. Summary of the Invention

[0006] In view of the shortcomings of the prior art described above, the technical problem to be solved by the present invention is to provide an in-situ fixation method for river and lake bottom sediment in a chaff suction flow state.

[0007] This invention proposes an in-situ fixation method for river and lake bottom sediment in a siphon-flush state, comprising a slurry preparation system and a centrifugal slurry preparation system. The slurry preparation system includes a first siphon device and a slurry preparation device. The slurry preparation device is installed on the shore or inside a mobile container. One end of the first siphon device is connected to the slurry preparation device, and the other end of the first siphon device extends into the river and lake bottom sediment. The centrifugal slurry preparation system includes a second siphon device, a centrifugal slurry preparation device, and a slurry discharge device for discharging the centrifugal slurry. The centrifugal slurry preparation device is installed on a ship. One end of the second siphon device is connected to the centrifugal slurry preparation device, and the other end of the second siphon device extends into the river and lake bottom sediment. The slurry discharge device is installed on the ship. Fixing river and lake bottom sediment using the slurry preparation system and the centrifugal slurry preparation system includes the following steps:

[0008] In the matured mud preparation stage, the river and lake bottom mud is drawn into a fluid state by the first suction device and then sucked into the matured mud preparation device. The river and lake bottom mud is then subjected to chemical addition, oxygen injection, flocculent biological culture and dewatering processes to complete the matured mud preparation.

[0009] In the centrifugal mud blank preparation stage, a dredging baseline is set at the bottom of the river and lake. A second suction device is inserted into the river and lake bottom mud above the dredging baseline for suction cleaning. The suctioned river and lake bottom mud, which is in a flow state, is then fed into the centrifugal mud blank preparation device through the second suction device. The river and lake bottom mud in the centrifugal mud blank preparation device is then subjected to chemical addition, oxygenation, and centrifugation processes in sequence. Then, mature mud is added to the bottom mud from the first centrifugation. Through centrifugation and drainage processes, the preparation of the centrifugal mud blank is completed.

[0010] During the sediment fixation stage, the second suction device is inserted into the river and lake sediment below the dredging baseline to suction, forming multiple pits in the river and lake sediment below the dredging baseline; the prepared centrifugal mud blank is transferred to the mud discharge device, and the centrifugal mud blank is buried in the pits through the mud discharge device.

[0011] Preferably, the centrifugal mud preparation stage further includes the following steps: the river and lake bottom sediment in the centrifugal mud preparation device is centrifuged after chemical dosing and oxygenation processes. After the river and lake bottom sediment shows obvious stratification, the centrifugation operation is stopped. Then, excess water in the river and lake bottom sediment is removed, leaving some water in the remaining sediment, and the volume ratio of the remaining sediment to the water is 1:1. Then, the matured mud is added to the remaining sediment, and the volume ratio of the remaining sediment to the matured mud is 4:3. Finally, the remaining sediment and the matured mud are centrifuged to remove water, thus completing the preparation of the centrifugal mud blank.

[0012] Preferably, the sludge discharge device includes a sludge storage pipe for placing the centrifuged sludge blank, a sludge discharge pipe, a pressure rod, and a switch plate. The bottom of the sludge discharge pipe is open, and the sludge storage pipe is detachably fixed inside the sludge discharge pipe. The end of the pressure rod is provided with a pressure plate, which can be movably extended into the sludge storage pipe and contacts the inner wall of the sludge storage pipe. The end of the pressure rod away from the pressure plate is connected to a hydraulic device on the ship. The switch plate is movably disposed at the bottom of the sludge storage pipe, and the switch plate is initially in a closed state. When the pressure plate presses down on the centrifuged sludge blank in the sludge storage pipe, the switch plate automatically opens. After the centrifuged sludge blank is discharged, the switch automatically closes.

[0013] Preferably, the inner wall of the sludge discharge pipe is provided with multiple drain pipes, and the inlet of the drain pipe is located at the bottom of the sludge discharge pipe, while the outlet of the drain pipe is higher than the water surface, so as to discharge part of the water in the pit.

[0014] Preferably, in the preparation stage of the matured mud, the agents added in the dosing process include iron agents, manganese agents, or iron-manganese compound agents, and the addition is stopped when the river and lake sediment produces flocculation; when the iron content in the river and lake sediment is not less than 15 mg / kg and the manganese content is less than 500 mg / kg, no iron agent is added; when the iron content in the river and lake sediment is less than 15 mg / kg and the manganese content is not less than 500 mg / kg, no manganese agent is added; the dosing process in the centrifuged mud preparation stage is the same as the dosing process in the preparation stage of the matured mud.

[0015] Preferably, the initial centrifugation speed is 800 r / min to 1000 r / min, and the centrifugation time is 4 min to 6 min.

[0016] Preferably, the second centrifugation speed is 1×10⁻⁶. 4 r / min ~1.5×10 4 The centrifugation speed was 8 min to 12 min.

[0017] Preferably, the bottom sediment fixation stage further includes the following steps: after the centrifuged mud blank is placed in the pit, oxygen is supplied at a distance of 20cm to 25cm above the dredging baseline for 7 to 10 days to ensure that the centrifuged mud blank is completely fixed in the pit.

[0018] Preferably, the matured sludge preparation stage specifically includes the following steps: the matured sludge preparation device includes a first oxygen injection tank; in the oxygen injection process, micro-nano bubble water is injected into the first oxygen injection tank, and the tank is treated for 24 hours at an aeration rate of 1 liter of air / (liter of water·hour) to 2.5 liters of air / (liter of water·hour); then aerobic manganese oxidizing bacteria and aerobic iron oxidizing bacteria are added to the first oxygen injection tank to ensure that the bottom sludge concentration is maintained at 5 kg / m³. 3 -7kg / m3 .

[0019] Preferably, the preparation stage of the matured mud specifically includes the following steps: the temperature of the floc biological culture is 20℃~25℃, the pH is 7~7.2, the culture time is 7 days, the oxygen injection is stopped after the floc biological culture is completed, and when the dissolved oxygen concentration in the first oxygen injection box is not higher than 3.5mg / L, anaerobic manganese oxidizing bacteria and anaerobic iron oxidizing bacteria are added to the first oxygen injection box, and the water is immediately removed through a dehydration process.

[0020] As described above, the in-situ fixation method for river and lake bottom sediment in a chaff suction flow manner, which relates to the present invention, has the following technical effects:

[0021] This invention utilizes a slurry preparation system to suction river and lake sediment into a slurry preparation device, and then further processes the sediment through chemical addition, oxygenation, flocculent biological culture, and dewatering to obtain slurry. A centrifugal sediment preparation system then suctions the sediment into a centrifugal sediment preparation device, followed by chemical addition, oxygenation, and an initial centrifugation process to obtain initial centrifuged sediment. Slurry is then added to the initial centrifuged sediment, and centrifugation and drainage are performed to complete the preparation of centrifugal sediment blanks. Finally, a second suction device creates multiple pits in the river and lake sediment below the dredging baseline, and the prepared centrifugal sediment blanks are buried in these pits using a sediment discharge device, thereby effectively immobilizing heavy metals.

[0022] This invention employs a method of fluidizing and then fixing and stabilizing river and lake bottom sediment using a squeegee, enabling the sludge to be returned to the river and lake bottom in a short time for in-situ fixation. This saves time and labor, and improves work efficiency. Using this method for in-situ fixation of river and lake bottom sediment, the fluidized river and lake bottom sediment can be directly squeegeed to prepare semi-stabilized centrifugal sediment blanks. The upper layer of stabilizing bottom sediment reduces sediment upwelling, promoting slow fixation of the centrifugal sediment blanks within the pit, effectively preventing contaminated bottom sediment from polluting the overlying water. This also reduces the difficulty of in-situ remediation of river and lake bottom sediment and saves economic costs. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the sludge preparation system provided in an embodiment of the present invention.

[0024] Figure 2 This is a schematic diagram of a centrifugal clay preparation system provided in an embodiment of the present invention.

[0025] Figure 3 This is a schematic diagram of the sludge storage tube being centrifuged according to an embodiment of the present invention.

[0026] Figure 4 This is a schematic diagram of a sludge removal device provided in an embodiment of the present invention.

[0027] Explanation of reference numerals in the attached figures:

[0028] 100. Sludge preparation system; 110. First suction device; 120. Sludge preparation device; 121. First dosing tank; 122. First oxygen injection tank; 123. Dewatering machine; 200. Centrifugal sludge preparation system; 210. Second suction device; 220. Centrifugal sludge preparation device; 221. Second oxygen injection tank; 222. Second dosing tank; 223. Centrifuge; 230. Sludge discharge device; 231. Sludge storage pipe; 232. Sludge discharge pipe; 233. Pressure bar; 234. Switch plate; 235. Drainage pipe; 236. Centrifuge pipe; 300. Dredging baseline; 400. Pit; 500. Water surface. Detailed Implementation

[0029] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

[0030] It should be understood that the structures, proportions, sizes, etc., illustrated in the accompanying drawings of this specification are merely for illustrative purposes to aid those skilled in the art and are not intended to limit the scope of the invention. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, the terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and are not intended to limit the scope of the invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention.

[0031] like Figure 1-2 As shown, this invention provides an in-situ fixation method for river and lake bottom sediment in a slurry flow state, including a slurry preparation system 100 and a centrifugal slurry preparation system 200. The slurry preparation system 100 includes a first slurry suction device 110 and a slurry preparation device 120. The slurry preparation device 120 is installed on the bank or in a mobile container. One end of the first slurry suction device 110 is connected to the slurry preparation device 120, and the other end of the first slurry suction device 110 extends into the river and lake bottom sediment. Further, the slurry preparation device 120 includes two first chemical dosing tanks 121, two first oxygen injection tanks 122, and a dewatering machine 123. The dewatering machine 123 is installed on the bank or in a mobile container. The first chemical dosing tanks 121 and the first oxygen injection tanks 122 are symmetrically arranged on both sides of the dewatering machine 123. The first chemical dosing tanks 121 and the first oxygen injection tanks 122 are connected by pipes. One end of the first slurry suction device 110 is connected to the first chemical dosing tank 121.

[0032] The centrifugal mud preparation system 200 includes a second suction device 210, a centrifugal mud preparation device 220, and a mud discharge device 230 for discharging the centrifugal mud. The centrifugal mud preparation device 220 is installed on a ship. One end of the second suction device 210 is connected to the centrifugal mud preparation device 220, and the other end of the second suction device 210 extends into the river or lake bottom mud. The mud discharge device 230 is installed on a ship. Further, the centrifugal mud preparation device 220 includes two second chemical dosing tanks 222, two second oxygen injection tanks 221, and a centrifuge 223. The centrifuge 223 is fixed on the ship. The second chemical dosing tanks 222 and the second oxygen injection tanks 221 are symmetrically arranged on both sides of the centrifuge 223. The second chemical dosing tanks 222 and the second oxygen injection tanks 221 are connected by pipes. One end of the second suction device 210 is connected to the second chemical dosing tank 222.

[0033] Furthermore, such as Figure 2-3 As shown, the sludge discharge device 230 includes a sludge storage pipe 231 for holding centrifuged sludge blanks, a sludge discharge pipe 232, a pressure rod 233, and a switch plate 234. The bottom of the sludge discharge pipe 232 is open to ensure smooth discharge of the centrifuged sludge blanks. The sludge storage pipe 231 is fixed inside the sludge discharge pipe 232 by a detachable connector. The pressure rod 233 has a pressure plate at its end, which can extend into the sludge storage pipe 231 and contacts the inner wall of the sludge storage pipe 231. The end of the pressure rod 233 away from the pressure plate is connected to a hydraulic system on the ship. The switch plate 234 is connected to the bottom of the sludge storage pipe 231 by an elastic reset member, and the switch plate 234 is initially in a closed state. When the pressure plate presses down on the centrifuged sludge blanks in the sludge storage pipe 231, the switch plate 234 automatically opens. After the centrifuged sludge blanks are discharged, the switch plate 234 automatically closes under the action of the elastic reset member.

[0034] Furthermore, the inner side of the sludge discharge pipe 232 is provided with 2 to 4 drain pipes 235, and the inlet of the drain pipe 235 is located at the bottom of the sludge discharge pipe 232. The outlet of the drain pipe 235 is higher than the water surface, so as to discharge part of the water in the pit 400, so that the centrifugal mud blank discharged from the sludge storage pipe 231 can adhere to the bottom mud in the pit 400.

[0035] like Figure 2 As shown, the process of fixing river and lake bottom sediment using the above-mentioned matured mud preparation system 100 and centrifugal mud preparation system 200 specifically includes the following steps:

[0036] In the sludge preparation stage, the first suction device 110 suctions the river and lake bottom sediment into a fluid state and then draws it into the sludge preparation device 120. The fluid river and lake bottom sediment undergoes chemical addition, oxygenation, flocculent biological culture and dewatering processes in the sludge preparation device 120 to complete the sludge preparation.

[0037] Specifically, the fluidized river and lake sediment suctioned by the first suction device 110 is fed into the first chemical dosing tank 121 for chemical dosing and floc formation. The floc-forming fluidized river and lake sediment is then transported to the first oxygenation tank 122 for oxygen supply. The oxygenated flocs are then subjected to biological cultivation, during which iron and manganese oxidizing bacteria are added to the first oxygenation tank 122. This removes manganese ions from the water and generates iron and manganese oxides, improving the fixation of heavy metals. After the floc biological cultivation is complete, the floc-containing fluidized river and lake sediment is transferred to the dewatering machine 123 for dewatering, resulting in matured sediment.

[0038] Furthermore, the chemicals added during the dosing process include iron, manganese, or iron-manganese compound agents to accelerate the stabilization of fluidized river and lake sediments. Addition is stopped when flocculation occurs in the sediments. Iron agents can be Fe2O3 and Fe3O4, and manganese agents can be MnO, MnO2, Mn2O3, and Mn3O4. No iron agents are added when the iron content in the sediments is not less than 15 mg / kg and the manganese content is less than 500 mg / kg; no manganese agents are added when the iron content is less than 15 mg / kg and the manganese content is not less than 500 mg / kg. During the dosing process, it is important to note that the minimum dosage of iron, manganese, or iron-manganese compound agents should be used, and dosing should be stopped when flocculation occurs in the first dosing tank 121. When the iron and manganese content of the fluidized river and lake sediments is already low, the dosage can be appropriately increased to save on economic costs. Because the sediment in natural rivers and lakes has extremely high iron and manganese content, the above-mentioned chemical addition process can accelerate the stabilization of the sediment.

[0039] Furthermore, oxygen is supplied to the first oxygen injection tank 122 via a micro-nano bubble generator. Micro-nano bubble water is first injected into the first oxygen injection tank 122, and the tank is treated for 24 hours at an aeration rate of 1 liter of air / (liter of water·hour) to 2.5 liters of air / (liter of water·hour). Then, aerobic manganese-oxidizing bacteria and aerobic iron-oxidizing bacteria are added to the first oxygen injection tank 122 to ensure that the sediment concentration is maintained at 5 kg / m³. 3 -7kg / m 3 This ensures the smooth progress of subsequent flocculent biological culture processes.

[0040] Furthermore, during the flocculant culture, the temperature was maintained at 20℃~25℃ for 7 days, and the pH was maintained at 7~7.2. Oxygenation was stopped after the flocculant culture was completed. Once the dissolved oxygen concentration in the first oxygenation tank 122 was no higher than 3.5 mg / L, anaerobic manganese oxidizing bacteria and anaerobic iron oxidizing bacteria were added to the first oxygenation tank 122, and the mixture was immediately dehydrated using a dewatering machine 123, thus completing the preparation of matured sludge and preparing it for the complex application environment of river and lake sediments. Specifically, the manganese oxidizing bacteria utilize oxygen in the water to oxidize manganese ions into manganese oxides, thereby removing manganese ions from the water. The bio-iron manganese compounds formed by ferric iron have a significant fixation effect on arsenic and lead in river and lake sediments. It is important to emphasize that the addition ratio of aerobic iron oxidizing bacteria and aerobic manganese oxidizing bacteria is 20% of the dry basis of the dredged river and lake sediment. The compound ratio of the two is calculated based on the manganese-iron ratio contained in the dredged river and lake sediment, and the dosage of the added chemicals in the river and lake sediment is negligible during the calculation.

[0041] like Figure 2 As shown, in the centrifugal mud blank preparation stage, a dredging baseline 300 is set at the bottom of the river or lake. The second suction device 210 is inserted into the river or lake bottom sediment above the dredging baseline 300 to suction and clean all the soft bottom sediment above the dredging baseline 300. The remaining hard bottom sediment below the dredging baseline 300 does not need to be cleaned. The suctioned river or lake bottom sediment, now in a fluid state, is then fed into the centrifugal mud blank preparation device 220 through the second suction device 210. The fluidized river or lake bottom sediment in the centrifugal mud blank preparation device 220 undergoes a series of processes including chemical addition, oxygenation, and centrifugation. Then, matured mud is added to the first centrifuged bottom sediment. Through centrifugation and drainage processes, the centrifugal mud blank preparation is completed.

[0042] Specifically, the fluidized river and lake sediment suctioned by the second suction device is fed into the second dosing tank 222 to generate flocs. The resulting floc-forming fluidized river and lake sediment is then transported to the second oxygenation tank 221 for oxygenation and cultivation. Floc biological cultivation is then performed using the same method as in the aforementioned sludge preparation stage. After the floc biological cultivation is complete, the floc-containing fluidized river and lake sediment is transferred to the sediment storage tube 231. The sediment storage tube 231 is placed inside a centrifuge tube 236, and the centrifuge tube 236 is placed in a centrifuge for the first centrifugation at a speed of 800-1000 rpm for 4-6 minutes. Centrifugation is stopped once clear stratification appears in the sediment storage tube 231. Then, the sediment storage tube 231 is removed to remove excess water, ensuring that some water remains in the remaining sediment within the tube, with a volume ratio of remaining sediment to water of 1:1. Next, add the matured mud to the remaining bottom mud in the mud storage tube 231, with a volume ratio of the remaining bottom mud to the matured mud of 4:3. Finally, place the mud storage tube 231 into the centrifuge tube 236, and place the centrifuge tube 236 into the centrifuge 223 for a second centrifugation at a speed of 1×10⁻⁶. 4r / min ~1.5×10 4 The centrifugation speed is set at 8-12 r / min, and the centrifugation time is 8-12 min. This allows the remaining bottom mud and matured mud to adhere firmly together to form a centrifuged mud blank. The moisture is then removed, and the preparation of the centrifuged mud blank is completed.

[0043] It should be noted that the chemicals added to the second chemical addition tank 222 in the chemical addition process are the same as those added in the preparation of matured sludge, and the oxygenation process in the preparation of centrifuged sludge blanks is the same as the oxygenation process in the preparation of matured sludge. In the flocculent biological culture process, the microorganisms added to the second oxygenation tank 221 are the same as those in the preparation of matured sludge.

[0044] like Figure 2 As shown, during the sediment fixation stage, the second suction device 210 is inserted into the hard river and lake sediment below the dredging baseline 300 to perform suction, creating multiple pits 400 in the sediment below the dredging baseline 300. The prepared centrifuged mud blanks are then transferred to the mud discharge device 230, which buries the centrifuged mud blanks into the pits 400. The diameter and depth of the pits 400 can be determined by the working diameter of the suction cutter head in the second suction device 210.

[0045] Specifically, after the centrifuged mud blanks are prepared, the mud storage pipe 231 is transferred to the mud discharge pipe 232, and the mud discharge pipe 232 is aligned with each pit 400. At this time, some of the water in the pit 400 is discharged along the drain pipes 235 under the action of deep water pressure. The pressure rod 233 connected to the hydraulic device on the ship is pressed into the mud storage pipe 231. As the pressure rod 233 is pressed downward, when the pressure rod 233 presses down on the centrifuged mud blank, the switch plate 234 is automatically opened, and the centrifuged mud blank is discharged from the mud storage pipe 231 into the pit 400. After some water is discharged from the pit 400, it can promote the adhesion of the centrifuged mud blank to the river and lake bottom mud in the pit 400.

[0046] Furthermore, the matured mud is compacted and backfilled into the pit 400, and the centrifuged mud blocks are buried in the pit 400. Then, micro-nano bubbles are set at a distance of 20cm to 25cm above the dredging baseline to supply oxygen and maintain it for 7 to 10 days to ensure that the centrifuged mud blocks are completely fixed in the pit 400, reduce the upwelling of river and lake bottom sediment below the dredging baseline 300, and prevent pollutants in the river and lake bottom sediment from being released into the overlying water.

[0047] In summary, this invention employs a method of fluidizing and then fixing and stabilizing river and lake bottom sediments using a slurry suction system. This allows for the rapid return of sludge to the river and lake bottom for in-situ fixation, saving time and labor and improving work efficiency. The method of this invention for in-situ fixation of river and lake bottom sediments allows for the direct preparation of semi-stabilized centrifugal sediment blanks after slurry suction. The stabilizing effect of the upper layer of bottom sediment reduces sediment upwelling, promoting slow fixation of the centrifugal sediment blanks within the pit, effectively preventing contaminated bottom sediment from polluting the overlying water. Simultaneously, it reduces the difficulty of in-situ remediation of river and lake bottom sediments and saves economic costs.

[0048] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for in-situ fixation of river and lake bottom sediment in a chaff suction flow state, characterized in that, The system includes a sludge preparation system (100) and a centrifugal sludge preparation system (200). The sludge preparation system (100) includes a first suction device (110) and a sludge preparation device (120). The sludge preparation device (120) is installed on the shore or in a mobile container. One end of the first suction device (110) is connected to the sludge preparation device (120), and the other end of the first suction device (110) extends into the bottom mud of the river or lake. The centrifugal sludge preparation system (200) includes a second suction device. (210), a centrifugal mud preparation device (220), and a mud discharge device (230) for discharging the centrifugal mud blanks, wherein the centrifugal mud preparation device (220) is installed on a boat, one end of the second suction device (210) is connected to the centrifugal mud preparation device (220), and the other end of the second suction device (210) extends into the river and lake bottom mud; the mud discharge device (230) is installed on a boat; the river and lake bottom mud is fixed by the maturation mud preparation system (100) and the centrifugal mud preparation system (200), including the following steps: In the sludge preparation stage, the river and lake bottom sediment is drawn into a fluid state by the first suction device (110) and sucked into the sludge preparation device (120). The river and lake bottom sediment undergoes chemical addition, oxygen injection, flocculent biological culture and dewatering processes in the sludge preparation device (120) to complete the sludge preparation. In the centrifugal mud blank preparation stage, a dredging baseline (300) is set at the bottom of the river and lake. The second suction device (210) is inserted into the river and lake bottom mud above the dredging baseline (300) for suction cleaning. The suctioned river and lake bottom mud in a flow state enters the centrifugal mud blank preparation device (220) through the second suction device (210). The river and lake bottom mud in the centrifugal mud blank preparation device (220) is subjected to chemical addition, oxygen injection and first centrifugation in sequence. Then, mature mud is added to the bottom mud after the first centrifugation. The centrifugal mud blank preparation is completed through the second centrifugation and drainage process. During the sediment fixation stage, the second suction device (210) is inserted into the river and lake sediment below the dredging baseline (300) to perform suction, so that multiple pits (400) are formed in the river and lake sediment below the dredging baseline (300); the prepared centrifugal mud blank is transferred to the mud discharge device (230), and the centrifugal mud blank is buried in the pits (400) through the mud discharge device (230).

2. The in-situ fixation method for river and lake bottom sediment in a chaff suction flow state according to claim 1, characterized in that, The centrifuged clay preparation stage also includes the following steps: The river and lake bottom sediment in the centrifugal mud preparation device (220) is centrifuged after chemical addition and oxygenation. The centrifugation operation is stopped after the river and lake bottom sediment shows obvious stratification. Then, excess water in the river and lake bottom sediment is removed, leaving some water in the remaining sediment, and the volume ratio of the remaining sediment to the water is 1:

1. Then, the matured mud is added to the remaining sediment, and the volume ratio of the remaining sediment to the matured mud is 4:

3. Finally, the remaining sediment and the matured mud are centrifuged to remove water, thus completing the preparation of the centrifugal mud blank.

3. The in-situ fixation method for siphon-flow river and lake bottom sediment according to claim 1 or 2, characterized in that, The sludge discharge device (230) includes a sludge storage pipe (231) for placing the centrifugal sludge blank, a sludge discharge pipe (232), a pressure rod (233), and a switch plate (234). The bottom of the sludge discharge pipe (232) is open, and the sludge storage pipe (231) is detachably fixed inside the sludge discharge pipe (232). The end of the pressure rod (233) is provided with a pressure plate, which can be movably extended into the sludge storage pipe (231) and contacts the inner wall of the sludge storage pipe (231). The end of the pressure rod (233) away from the pressure plate is connected to the hydraulic device on the ship. The switch plate (234) is movably disposed at the bottom of the sludge storage pipe (231) and is initially in a closed state. When the pressure plate presses down on the centrifugal sludge blank in the sludge storage pipe (231), the switch plate (234) automatically opens. After the centrifugal sludge blank is discharged, the switch plate (234) automatically closes.

4. The in-situ fixation method for river and lake bottom sediment in a chaff suction flow state according to claim 3, characterized in that, The inner wall of the sludge discharge pipe (232) is provided with multiple drain pipes (235), and the inlet of the drain pipe (235) is located at the bottom of the sludge discharge pipe (232). The outlet of the drain pipe (235) is higher than the water surface, so as to discharge part of the water in the pit (400).

5. The in-situ fixation method for river and lake bottom sediment in a chaff suction flow state according to claim 1, characterized in that, In the preparation stage of the matured mud, the agents added in the dosing process include iron agents, manganese agents, or iron-manganese compound agents. The addition is stopped when the river and lake sediment produces flocculation. When the iron content in the river and lake sediment is not less than 15 mg / kg and the manganese content is less than 500 mg / kg, no iron agent is added. When the iron content in the river and lake sediment is less than 15 mg / kg and the manganese content is not less than 500 mg / kg, no manganese agent is added. The dosing process in the centrifuged mud preparation stage is the same as the dosing process in the preparation stage of the matured mud.

6. The in-situ fixation method for river and lake bottom sediment in a chaff suction flow state according to claim 2, characterized in that, The initial centrifugation speed is 800 r / min to 1000 r / min, and the centrifugation time is 4 min to 6 min.

7. The in-situ fixation method for river and lake bottom sediment in a chaff suction flow state according to claim 2, characterized in that, The second centrifugation speed was 1×10⁻⁶. 4 r / min ~1.5×10 4 The centrifugation speed was 8 min to 12 min.

8. The in-situ fixation method for river and lake bottom sediment in a chaff suction flow state according to claim 1, characterized in that, The sediment stabilization stage also includes the following steps: After the centrifuged mud blank is placed in the pit (400), oxygen is supplied at a distance of 20cm to 25cm above the dredging baseline for 7 to 10 days to ensure that the centrifuged mud blank is completely fixed in the pit (400).

9. The in-situ fixation method for river and lake bottom sediment in a chaff suction flow state according to claim 1, characterized in that, The maturation mud preparation stage specifically includes the following steps: The matured sludge preparation device (120) includes a first oxygen injection tank (122). In the oxygen injection process, micro-nano bubble water is injected into the first oxygen injection tank (122) and treated for 24 hours at an aeration rate of 1 liter of air / (liter of water·hour) to 2.5 liters of air / (liter of water·hour). Then, aerobic manganese oxidizing bacteria and aerobic iron oxidizing bacteria are added to the first oxygen injection tank (122) to ensure that the sludge concentration in the first oxygen injection tank (122) is maintained at 5 kg / m³. 3 -7kg / m 3 .

10. The in-situ fixation method for river and lake bottom sediment in a chaff suction flow state according to claim 9, characterized in that, The matured mud preparation stage specifically includes the following steps: The temperature for the flocculent biological culture is 20℃~25℃, the pH is 7~7.2, and the culture time is 7 days. After the flocculent biological culture is completed, oxygen injection is stopped. When the dissolved oxygen concentration in the first oxygen injection box (122) is not higher than 3.5mg / L, anaerobic manganese oxidizing bacteria and anaerobic iron oxidizing bacteria are added to the first oxygen injection box (122), and water is removed immediately through a dehydration process.

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