CN111762984A - In-situ vacuum precipitation repairing method - Google Patents
In-situ vacuum precipitation repairing method Download PDFInfo
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- CN111762984A CN111762984A CN202010604412.1A CN202010604412A CN111762984A CN 111762984 A CN111762984 A CN 111762984A CN 202010604412 A CN202010604412 A CN 202010604412A CN 111762984 A CN111762984 A CN 111762984A
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/008—Sludge treatment by fixation or solidification
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F11/00—Treatment of sludge; Devices therefor
- C02F11/12—Treatment of sludge; Devices therefor by de-watering, drying or thickening
- C02F11/14—Treatment of sludge; Devices therefor by de-watering, drying or thickening with addition of chemical agents
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
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- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2301/00—General aspects of water treatment
- C02F2301/06—Pressure conditions
- C02F2301/063—Underpressure, vacuum
Abstract
The invention provides an in-situ vacuum precipitation remediation method, which relates to the technical field of sludge remediation and comprises the steps of arranging a plurality of medicament injection wells in sludge to be treated; laying geotextile; arranging a plurality of drainage plates, and connecting the upper ends of the drainage plates with the vacuum tubes; laying a sealing film, and sealing the edges of the geotextile and the sealing film; after the medicine is injected into the medicine injection well, the medicine is diffused by vacuum extraction, and then precipitation is vacuum extracted. According to the in-situ vacuum precipitation remediation method provided by the invention, the medicament is injected through the medicament injection well, the medicament is diffused into the sludge by combining with the vacuum extraction operation and fully reacts with the sludge, so that the content of heavy metals in the sludge is reduced, the in-situ remediation of the sludge is realized, the establishment of the vertical drainage channel is realized by utilizing the plurality of drainage plates, the moisture in the sludge to be treated is rapidly pumped to the outside of the sludge by matching with the vacuum tube, the remediation of the sludge is realized, and the solidification and stabilization effects of the sludge are realized.
Description
Technical Field
The invention belongs to the technical field of sludge remediation, and particularly relates to an in-situ vacuum precipitation remediation method.
Background
In urban areas, with the acceleration of urbanization process in China, large and medium cities face the relocation of a large number of industrial enterprises. The fields left by the removed enterprises have pollution of different degrees, and the underground water and the surrounding water bodies of residents around the fields are all damaged. Particularly, a large amount of organic pollutants exist in the original site sludge after the removal of the pesticide factory, along with the infiltration of rainwater and irrigation water, a large amount of pollutants enter underground water to threaten human health and ecological environment, and the management and restoration of the site are urgently needed.
At present, the municipal sludge treatment mainly adopts the traditional modes of solidification stabilization landfill, incineration, high-temperature aerobic composting and the like, the former two methods have better application effect but are constrained by the large consumption of curing agents, the large volume of sludge, the limited landfill site and incineration site in China and the like; the latter high-temperature composting technology has the defects of low fermentation temperature, long fermentation period, incomplete harmlessness, serious odor pollution and the like, and becomes a bottleneck limiting the comprehensive popularization and application of the high-temperature composting technology. Any of the above disposal methods has problems of high sludge water content, extremely low bearing capacity, and incapability of satisfying mechanical construction.
Disclosure of Invention
The invention aims to provide an in-situ vacuum precipitation remediation method to solve the technical problems that in the prior art, the water content of sludge is high, the bearing capacity is low and the mechanical construction cannot be met in municipal sludge treatment.
In order to achieve the purpose, the invention adopts the technical scheme that: the in-situ vacuum precipitation repairing method comprises the following steps:
arranging a plurality of agent injection wells in the sludge to be treated, wherein joints are reserved at the upper ends of the agent injection wells;
laying geotextile above the sludge to be treated;
punching a plurality of drainage plates on the sludge to be treated, and connecting the upper ends of the drainage plates with vacuum tubes;
laying a sealing film above the sludge to be treated, the agent injection well, the drainage plate and the vacuum pipe, penetrating a joint of the agent injection well and the vacuum pipe through the sealing film, fastening the sealing film at the penetrating position, and sealing the edges of the geotextile and the sealing film;
after the medicine is injected into the medicine injection well, the medicine is diffused by vacuum extraction, and then precipitation is vacuum extracted.
The in-situ vacuum precipitation repair method provided by the invention has the beneficial effects that: compared with the prior art, the in-situ vacuum precipitation remediation method provided by the invention has the advantages that the agent is injected through the agent injection well and is combined with vacuum extraction, so that the agent is diffused into the sludge of the sludge to be treated and is fully reacted with the sludge, the content of heavy metals in the sludge is reduced, the in-situ remediation of the sludge is realized, the vertical drainage channel is established by utilizing the plurality of drainage plates, the water in the sludge to be treated is rapidly pumped to the outside of the sludge by matching with the vacuum tube, the remediation of the sludge is realized, and the solidification and stabilization effects of the sludge are realized.
The injection wells are arranged in a plurality of wells, and the average coverage area is 80-100 square meters. According to the specific area of the sludge to be treated, the number of the agent injection wells needs to be correspondingly adjusted, so that the agent can cover the whole area of the sludge to be treated in the subsequent diffusion process, and the treatment effect of the sludge is ensured. The upper end of the medicament injection well is provided with a connector which is used for being connected with the medicament containing box, and the medicament in the medicament containing box is injected into the medicament injection well through an injection pump.
The injection well is made of PVC hard plastic pipe, the diameter of the injection well is 70-80mm, and the lower end of the injection well is closed. The injection pressure is designed to be more than 40MPa, so that the permeation range of the medicament can cover the whole sludge to be treated. The periphery of the part of the body of the agent injection well, which is positioned in the sludge, is provided with liquid outlet holes, the body is not provided with liquid outlet holes in the height of half a meter below the surface of the sludge, the good sealing performance of the upper end of the agent injection well is ensured, and the permeation effect on the sludge in the height of half a meter on the surface layer is realized through the liquid outlet holes close to the upper end of the body. Meanwhile, the liquid outlet hole is not formed in the height of half meter at the lowest end of the pipe body, and the permeation effect on sludge is realized through the liquid outlet hole close to the lower end of the pipe body.
The agent adopts a solidification stabilizer in sludge treatment. The sludge curing agent is also called as sludge curing agent, and can improve the unconfined compressive strength of the sludge, and increase the hardness and the waterproof effect of the sludge. Can effectively improve sludge pollution, remove sludge odor, solidify heavy metal, reduce COD, change various sludge into recyclable soil or planting soil, and can be widely applied to sludge treatment to realize the solidification and stabilization effect of the medicament on the sludge.
The sludge curing agent is used in the sludge, and a physical and chemical reaction can occur between the sludge curing agent and the sludge curing agent, so that on one hand, after the curing agent is added, the colloidal property of the sludge is immediately destroyed, a capillary channel is quickly established, increased and diffused, so that the volatile channel for the moisture in the sludge to diffuse outwards is opened, and the sludge is favorably and quickly dried; on the other hand, the curing agent, the free moisture in the sludge and the moisture released by gel breaking are subjected to hydrolysis and hydration reactions to generate a large amount of gelled substances and chain-shaped crystalline substances, so that the sludge integrally forms a compact and slightly-voided integral microscopic honeycomb structure, the sludge property is changed, and the sludge has certain structural strength.
Preferably, the drainage plates are plastic drainage plates, the drainage plates are arranged on the horizontal plane in a matrix manner, the distance between every two adjacent drainage plates is 0.8-1.2 m, the driving depth of the drainage plates is 0.4-0.6 m smaller than the depth of sludge to be treated, and the length of the drainage plates exposed out of the sludge is 0.5-0.7 m. The arrangement density of the drainage plates can ensure the comprehensiveness of the drainage plates in covering the surrounding sludge. The upper end of the drainage plate is exposed out of the sludge for a certain length and is used for being connected with the vacuum tube. Utilize the picture peg machine to beat in pending mud and establish the drain bar, even pending mud has higher moisture content, after laying geotechnological cloth, geotechnological cloth also can realize the effective bearing to with the picture peg machine.
Preferably, the upper ends of the drainage plates are connected with the vacuum tubes through butterfly joints, and two adjacent rows of drainage plates are connected to the same vacuum tube. Two lines of drain bars carry out evacuation through a vacuum tube and handle, when guaranteeing the negative pressure effect, are convenient for reduce the quantity of arranging of vacuum tube, have reduced the consumption of vacuum tube, have improved operating efficiency simultaneously.
Preferably, the vacuum pipe includes a branch pipe for connection with the drain plate, and a main pipe for connection with the branch pipe. The vacuum pipe is a flexible thread hard plastic pipe, the branch pipes are directly connected with the drainage plate, the branch pipes are connected in parallel, and finally collected to the main pipe and connected with an external vacuumizing device through the main pipe. The diameter of the main pipe is larger than that of the branch pipe, so that smooth flow of water flow is guaranteed. The designed compressive strength of the vacuum tube is greater than 400 kPa.
Preferably, the geotextile is provided with one layer, and the sealing membrane is provided with two layers. After the drainage plate and the vacuum pipe are arranged, at least two layers of sealing films are paved above the geotextile to form effective sealing for the sludge. The sealing film is a black PVC sealing film, a stable negative pressure environment can be formed by arranging two layers of sealing films, the stability of vacuum extraction is ensured, the energy loss can be avoided to the maximum extent, and the speed and the efficiency of vacuum extraction are improved.
The surface layer of the sludge to be treated is firstly paved with a layer of geotextile, wherein the geotextile refers to geotextile, the geotextile is a water-permeable geosynthetic material formed by needling or weaving synthetic fibers, and the finished product is in a cloth shape. Because the tensile strength of geotechnical cloth is high, lay geotechnical cloth on the lower mud of water content, bearing capacity and can improve geotechnical cloth and bear the ability of loading, carry out inserting of drain bar for follow-up picture peg machine and provide reliable bearing basis, avoid the picture peg machine to be absorbed in mud. Simultaneously, geotechnological cloth can also form the protection of certain degree to the seal membrane, avoids sharp object direct contact seal membrane in the mud to cause the damage of seal membrane, and then influences negative pressure environment's formation.
The geotextile adopts staple fiber needle-punched non-woven geotextile, the specification is randomly selected between 100g/m2-600g/m2, and the main raw material is polyester staple fiber or polypropylene staple fiber which is made by a needle-punching method. In the embodiment, the short-filament needle-punched non-woven geotextile with the specification of 200g/m2 is selected to achieve the effect of bearing the load of the plate inserting machine.
The geotextile can prevent water in the sludge from permeating into the upper layer of the geotextile, so that the influence on the plate inserting process of the plate inserting machine is avoided. When the geotextile is laid, the field is leveled, and the height difference of the leveled field is controlled to be +/-5 cm. The cloth cover of the geotextile needs to be smooth, and deformation allowance is properly reserved, so that the geotextile is prevented from being heavily pressed and torn in the plate inserting process of the plate inserting machine.
In addition, when the connector of the medicament injection well and the end of the main pipe are led out from the two layers of sealing films, the connector position needs to be tightly bound and tightened, and the sealing performance inside the sealing films is guaranteed.
Preferably, when the edges of the geotextile and the sealing membrane are sealed, a groove is dug at the edge of the sludge to be treated, the edges of the geotextile and the sealing membrane are pressed into the groove, and the groove is filled with dug soil and compacted. In order to ensure the sealing performance of the edge parts of the geotextile and the sealing film, the edges of the geotextile and the sealing film are buried in the excavated groove, so that the effective sealing of the sealing film on the sludge to be treated is ensured. The groove adopts an operation mode of manually cooperating with mechanical excavation, the depth of the groove is required to cut off the permeable layer, the depth is more than 1 meter, and the inner side slope of the groove can be set to be 2:1, and the section of the groove is inverted trapezoidal. After the groove is dug, sundries at the bottom of the groove are thoroughly removed to avoid puncturing the sealing film. And reserving 1m wide edges for cofferdam water retaining after the sealing films are laid. And after the sealing film is buried, backfilling the excavated soil into the ditch and compacting.
Preferably, the membrane is checked for empty vacuum before injecting the medicament into the medicament injection well. And (3) sealing the sealing film by using the groove, then installing a vacuumizing device, and checking whether the vacuum degree meets the design requirement in the no-load process before vacuumizing the drainage plate. After each vacuum-pumping device is arranged in place, the vacuum-pumping is started. At the stage of starting vacuumizing, the sealing state of the sealing film and the sealing ditch is comprehensively checked along with the discharge of air and water, if air leaks, the air leaking part is timely repaired and sealed, and the vacuum effect is prevented from being influenced.
The vacuum pumping device consists of a vacuum pump, a pipeline, a vacuum tank, a vacuum exhaust chamber, a ball valve and a pipeline. The vacuum pump adopts a water ring type, a motor drives a rotor to rotate at a high speed to form gas flow, the pumped part forms negative pressure (namely vacuum) by utilizing the sealing property of water, so that water is pumped out through a pipeline and an exhaust chamber, and the pumped water and waste gas pass through a vacuum tank to cool and filter solid impurities so as to prevent the vacuum pump from being damaged.
Preferably, when the medicament is injected into the medicament injection well discontinuously, the medicament is injected into the medicament injection well for 0.8 to 1.2 hours every 3 to 5 hours, the injection amount of the medicament is 1.5 to 2.5 cubic meters, continuous extraction is respectively carried out after each medicament injection is finished, and vacuum extraction precipitation is carried out after multiple continuous extractions are finished.
Preferably, before a plurality of agent injection wells are arranged in the sludge to be treated, a plain soil cushion layer is paved on the surface layer of the sludge to be treated, and the thickness of the plain soil cushion layer is more than 30 cm.
Drawings
In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings needed to be used in the embodiments or the prior art descriptions will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without inventive exercise.
Fig. 1 is a position layout diagram of a drainage plate, a vacuum pipe and an agent injection well in an in-situ vacuum precipitation remediation method provided by an embodiment of the invention;
fig. 2 is a schematic cross-sectional structural diagram of longitudinal sections of sludge, a geomembrane, a sealing membrane and a groove in the in-situ vacuum precipitation remediation method provided by the embodiment of the invention.
Wherein, in the figures, the respective reference numerals:
1. a drain plate; 2. a vacuum tube; 21. a branch pipe; 22. a main pipe; 3. an agent injection well; 4. sludge to be treated; 5. geotextile; 6. a trench; 7. and (5) sealing the film.
Detailed Description
In order to make the technical problems, technical solutions and advantageous effects to be solved by the present invention more clearly apparent, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.
It will be understood that when an element is referred to as being "disposed on" another element, it can be directly on the other element or be indirectly on the other element. It will be understood that the terms "length," "width," "upper," "lower," "front," "rear," "top," "bottom," "inner," "outer," and the like are used in the orientation or positional relationship indicated in the drawings for ease of description and simplicity of description, and do not indicate or imply that the referenced device or element must have a particular orientation, be constructed in a particular orientation, and be constructed in a particular operation, and are therefore not to be considered limiting. The terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, "a number" means two or more unless specifically limited otherwise.
Referring to fig. 1 and 2 together, the in-situ vacuum precipitation remediation method provided by the present invention will now be described.
Example (b):
the length of the sludge 4 to be treated on the horizontal plane is 20 meters, the width is 20 meters, and the average depth of the sludge to be treated is 8.5 meters. The original site of the site is a pit formed after soil is taken by a brick kiln in a nearby village, and an impermeable film is laid at the bottom of sludge. The field service time is two years in total, the sludge is derived from sludge generated by peripheral leather processing sewage treatment plants, the water content is 60-80%, the total amount of heavy metal chromium and zinc is high, and the leaching sample of the water solution exceeds the III standard of underground water. And (3) performing sludge remediation on the area, wherein the remediation process is as follows:
four agent injection wells 3 are vertically arranged on the sludge 4 to be treated, and the average coverage area of each agent injection well 3 is 100 square meters. The agent injection well 3 is a PVC hard plastic pipe, the diameter of the agent injection well 3 is 75mm, and the lower end is closed. The injection pressure of the agent injection well 3 is designed to be more than 40MPa, so that the infiltration range of the agent can cover the whole sludge 4 to be treated. The periphery of the part of the body of the agent injection well 3 in the mud is provided with a liquid outlet hole, the body is not provided with a liquid outlet hole at the height of the half meter below the surface of the mud, the good sealing performance of the upper end of the agent injection well 3 is ensured, and the penetration effect of the liquid outlet hole close to the upper end of the body on the height of the half meter of the surface layer of the mud is realized. Meanwhile, the liquid outlet hole is not formed in the height of half meter at the lowest end of the pipe body, and the permeation effect on sludge is realized through the liquid outlet hole close to the lower end of the pipe body.
A layer of geotextile 5 is laid on the surface layer of the sludge 4 to be treated, and then the drainage plate 1 is arranged in the sludge 4 to be treated by utilizing the plate inserting machine, so that the plate inserting machine can be effectively supported. The arrangement interval of the drainage plate 1 is 1 meter, and the arrangement density can ensure the comprehensiveness of the drainage plate 1 to the surrounding sludge. As the treatment depth of the sludge is 8.5 meters, and the driving depth of the drainage plate 1 is less than the depth by half meter, the depth of the drainage plate 1 in the sludge is 8 meters, and the length of the sludge exposed from the upper end is 0.6 meter, which is used for connecting with the branch pipe 21 of the vacuum pipe 2.
Referring to fig. 1, the upper ends of the drainage plates 1 are connected to the branch pipes 21 through butterfly joints, and two adjacent rows of drainage plates 1 are connected to the same branch pipe 21. Two rows of drain bars 1 carry out evacuation processing through a branch pipe 21, when guaranteeing the negative pressure effect, are convenient for reduce arranging of vacuum tube 2, have reduced the consumption of vacuum tube 2, have improved operating efficiency simultaneously.
A plurality of branch pipes 21 are intensively connected with the same main pipe 22, the main pipe 22 and the branch pipes 21 are both flexible threaded hard plastic pipes, and the designed compressive strength of the vacuum pipe 2 is more than 400 kPa. Flexible screw thread stereoplasm plastic tubing has the flexible function of screw thread, is convenient for turn round laying of position, and the rigid material can avoid being responsible for when follow-up evacuation the shrivelled of 22 and branch pipe 21, influences the drainage of drain bar 1.
After the drainage plate 1 and the vacuum pipe 2 are arranged, two layers of sealing films 7 are paved above the geotextile 5 to form effective sealing for sludge. The sealing film 7 is a black PVC sealing film 7, and the arrangement of the two sealing films 7 can form a reliable vacuum negative pressure environment, so that the stability of vacuum extraction is ensured, the energy loss can be avoided to the maximum extent, and the speed and the efficiency of vacuum extraction are improved. The joint of the medicament injection well 3 and the vacuum tube 2 penetrate through the sealing membrane 7 and tighten the sealing membrane 7 at the penetrating part to ensure the sealing performance of the sealing membrane 7.
Referring to fig. 2, a trench 6 is dug at the edge of sludge 4 to be treated, and after the edges of geotextile 5 and sealing film 7 are pressed into the trench 6, the trench 6 is filled with sludge and compacted. The groove 6 adopts an operation mode of manual cooperation with mechanical excavation, a permeable layer is cut off at the depth of more than 1m, the inner side slope of the groove 6 can be set to be 2:1, the ratio of the height of the slope to the width of the slope is 2:1, and the groove 6 has an inverted trapezoidal longitudinal section. After the trench 6 is dug, the impurities at the bottom of the trench 6 are thoroughly removed to avoid puncturing the sealing film 7. After the sealing film 7 is laid, the edge with the width of 1m is reserved for cofferdam water retaining. And after the sealing film 7 is buried, backfilling the sludge into the ditch and compacting.
The sealing film 7 is sealed by the groove 6, then the vacuum-pumping device is installed, and whether the vacuum degree meets the design requirement when the drainage plate 1 is unloaded is checked before vacuum-pumping. After each vacuum-pumping device is arranged in place, the vacuum-pumping is started. At the stage of starting vacuumizing, the sealing state of the sealing film 7 and the sealing groove is comprehensively checked along with the discharge of air and water, if air leaks, the air leaking part is timely repaired and sealed, and the vacuum effect is prevented from being influenced.
When the chemicals are injected into the chemical injection well 3 intermittently, the chemicals are injected for 1 hour every 5 hours, the injection amount of the chemicals is 2 cubic meters, continuous extraction is performed after each injection of the chemicals is completed, and extraction precipitation operation is performed after the injection and extraction operations are completed for three times.
Compared with the prior art, the in-situ vacuum precipitation remediation method provided by the invention has the advantages that the agent is injected through the agent injection well 3, the agent is diffused into the sludge of the sludge 4 to be treated by combining with vacuum extraction, and the agent is fully reacted with the sludge to reduce the content of heavy metals in the sludge, so that the sludge is remediated in situ, the vertical drainage channels are established by utilizing the drainage plates 1, the water in the sludge 4 to be treated is rapidly pumped to the outside of the sludge by matching with the vacuum tubes 2, the sludge remediation is realized, and the solidification and stabilization effects of the sludge are realized.
And (4) analyzing results:
in the process of treating the sludge by the method, the following monitoring methods are utilized to carry out surface settlement monitoring, vacuum degree monitoring, water yield monitoring and stabilization analysis, and the specific monitoring process is as follows:
1. surface subsidence monitoring
The surface subsidence mark is arranged at 1 point of the center and the boundary of the field to be detected, the surface subsidence is detected by adopting a subsidence plate method, the size of the subsidence plate is 0.5m multiplied by 0.5m, and the subsidence plate is horizontally arranged on a black sealing film 7. The settlement rod is arranged on the settlement plate and is well pasted with the scale strip. During the vacuum pumping process, the sedimentation plate descends along with the surface sedimentation.
According to a recording meter for monitoring the surface subsidence, after the field is vacuumized for 13 days, the accumulated subsidence of the central point is 61.8cm, the accumulated subsidence of the boundary point is 37.8cm, and the subsidence effect is obvious. The settlement amount of the earth surface of the central area of the field is higher than that of the boundary earth surface, water-stop curtain construction is not performed in advance probably because the sludge 4 to be treated is vacuumized, and the porosity of the sludge of the field is high, so that gas and water in the sludge outside the boundary enter the vacuum preloading area of the sludge 4 to be treated along with negative pressure, and the consolidation rate of the boundary area of the vacuum preloading area is reduced.
2. Vacuum monitoring
And a vacuum degree monitoring point under the film is arranged in the vacuum preloading process, and the vacuum degree under the film consists of a PVC transparent hose with the diameter of 6 cm and a negative pressure vacuum meter. The hose is placed under the sealing membrane 7 in a serpentine arrangement to accommodate uneven deformation of the foundation and finally penetrates through the sealing membrane 7 to connect with a vacuum gauge.
As can be seen from the gauge for monitoring the vacuum degree under the membrane, the vacuum degree under the membrane is more than 80kpa 24 hours after the vacuum pumping is started, and the initial drainage consolidation effect is obvious. After 3 days, the vacuum degree under the film is slightly reduced, and after 10 days of vacuumizing, the vacuum degree under the film gradually reaches over 85kpa and tends to be stable.
3. Water yield monitoring
And in the vacuum preloading process, the height of the water outlet surface in the cofferdam is regularly measured every day, and the water outlet amount of every day of vacuumizing is calculated. According to the monitoring numerical value, after the vacuumizing is finished, the accumulated water yield is 56.7 cubic meters, and the water outlet effect is obvious.
4. Moisture content detection
And after the vacuumizing is finished, selecting sludge at the position of the center and the boundary point of the field, which is 0.2 m away from the surface of the sludge, carrying out moisture content detection, and comparing the moisture content with the moisture content of the sludge before treatment (see the moisture content detection result in table 1 for details). The comparison shows that the water content is reduced after 28 days of solidification and stabilization treatment, wherein the water content of the center point is reduced by 5.6%, the water content of the boundary point is reduced by 5%, and the dewatering effect of the center sludge is slightly better than that of the boundary, which indicates that the operation method is effective and feasible for accelerating sludge drainage and consolidation.
TABLE 1 Water content test results
5. Stabilization assay
After the agent injection and the vacuum extraction, the leaching concentration of the sludge is lower than a standard value, which shows that the agent diffusion and stabilization effects can be effectively improved by combining the multiple agent injection with the multiple vacuum extraction.
Therefore, the method has a good effect on the early treatment of the sludge, and the volume of the sludge can be reduced, and the landfill space and the disposal cost can be saved due to the discharge of a large amount of moisture in the sludge. In addition, the sludge with high water content has certain bearing capacity after being drained and consolidated, so that later mechanical consolidation construction is facilitated, the sludge property is thoroughly improved, the method provides a good way for sludge treatment in China, and the future development prospect is very good.
The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (10)
1. The in-situ vacuum precipitation repairing method is characterized by comprising the following steps:
arranging a plurality of agent injection wells in sludge to be treated, wherein joints are reserved at the upper ends of the agent injection wells;
laying geotextile above the sludge to be treated;
punching a plurality of drainage plates on the sludge to be treated, and connecting the upper ends of the drainage plates with vacuum tubes;
laying a sealing film above the sludge to be treated, the agent injection well, the drainage plate and the vacuum pipe, penetrating a joint of the agent injection well and the vacuum pipe through the sealing film, tightening the sealing film at the penetration position, and sealing the edges of the geotextile and the sealing film;
and after the medicament is injected into the medicament injection well, the medicament is diffused by vacuum extraction, and then precipitation is extracted by vacuum extraction.
2. The in-situ vacuum precipitation remediation method of claim 1, wherein the drainage plates are plastic drainage plates, the drainage plates are arranged in a matrix on a horizontal plane, the distance between every two adjacent drainage plates is 0.8-1.2 m, the driving depth of the drainage plates is less than 0.4-0.6 m of the depth of the sludge to be treated, and the length of the drainage plates exposed out of the sludge is 0.5-0.7 m.
3. The in-situ vacuum precipitation remediation method of claim 2 wherein the upper ends of said drainage plates are connected to said vacuum tubes by butterfly joints, two adjacent rows of said drainage plates being connected to the same said vacuum tube.
4. The in situ vacuum precipitation remediation method of claim 1 wherein said vacuum pipe includes a branch pipe for connection to said drain plate and a main pipe for connection to said branch pipe.
5. The in situ vacuum precipitation remediation method of claim 1 wherein said geotextile is provided with one layer and said sealing membrane is provided with two layers.
6. The in situ vacuum precipitation remediation method of claim 1 wherein the edges of the geotextile and the sealing membrane are sealed by digging a trench at the edge of the sludge to be treated, pressing the edges of the geotextile and the sealing membrane into the trench, burying the trench with sludge and compacting.
7. The in situ vacuum precipitation remediation method of claim 1 wherein said membrane is tested for an empty vacuum level prior to injecting said chemical into said chemical injection well.
8. The in-situ vacuum precipitation remediation method of any one of claims 1 to 7 wherein the injection of the chemical into the chemical injection well is performed intermittently by injecting the chemical into the chemical injection well a plurality of times, each time followed by vacuum extraction, and finally vacuum extracting the precipitation.
9. The in-situ vacuum precipitation remediation method of claim 8 wherein said agent is injected into said agent injection well at intervals of 3-5 hours for 0.8-1.2 hours, said agent being injected in an amount of 1.5-2.5 cubic meters, after each injection of said agent is completed, said extraction is continued, and after a plurality of said constant extractions, said precipitation is extracted under vacuum.
10. The in-situ vacuum precipitation remediation method of any one of claims 1 to 7 wherein a layer of plain soil mat is applied to the surface of the sludge to be treated, said layer having a thickness greater than 30 cm, prior to the deployment of a plurality of agent injection wells in the sludge to be treated.
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| CN (1) | CN111762984A (en) |
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