Reservoir desilting sludge fertilizer activation method and electrochemical device

Abstract

This invention proposes a method and electrochemical device for activating the fertility of dredged sludge from a reservoir, comprising the following steps: S1, adding a fertility activator to the sludge sample, adjusting the pH to 4-7, stirring, and then adding hydrogen peroxide solution to obtain the sludge to be treated; S2, setting a voltage gradient in the electrolytic cell, and initiating an electrochemical reaction by applying a gradient voltage and current to the sludge to promote the oxidative decomposition of nutrients in the sludge; S3, detecting the main control indicators of the sludge. If the detection is qualified, the reaction ends and proceeds to the next step; if the detection is unqualified, the concentration of the added fertility activator and the electrochemical operating parameters are adjusted according to the main control indicators, and the electrochemical reaction continues until the main control indicators are qualified; S4, ending the reaction, filtering and collecting the sludge, crushing and homogenizing it to obtain fertility-activated sludge. The above technical solution can improve the fertility activation effect of sludge and avoid secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of sludge treatment technology, and in particular to a method and electrochemical device for activating the fertilizer effect of dredged sludge from reservoirs. Background Technology

[0002] Dredging and cleanup projects in rivers, lakes, and reservoirs are crucial for effectively controlling pollution sources within these areas. The large amounts of silt generated during dredging and its subsequent treatment and disposal have become pressing issues. The resource utilization and treatment of this silt are currently a key concern in silt management. Current methods for silt resource utilization include soil application, building material processing, and filling materials. Due to the high nutrient content of dredged silt, soil application offers advantages such as large silt absorption capacity and good ecological benefits, showing broad application prospects. However, silt contains some heavy metals and other toxic and harmful substances, and its nutrients are difficult for plants to directly absorb, limiting its agricultural use. Therefore, modifying dredged silt to enhance its fertility and enable its direct use in planting soil is a pressing issue that needs to be addressed.

[0003] Currently, there are two main methods for preparing planting soil from river, lake, and reservoir silt. The first method involves using silt entirely from rivers, lakes, and reservoirs, and then modifying it with appropriate techniques to ensure its main control indicators meet relevant standards. The second method uses river, lake, and reservoir silt as a conditioner, mixing it with general soil to create nutrient-rich soil, enhancing its overall fertility and ensuring its main control indicators meet relevant standards. For the first method of directly preparing planting soil from modified river, lake, and reservoir silt, current methods primarily involve adding solidifying agents, biomass materials, other auxiliary materials, and organic fertilizers to modify the silt, such as adding straw powder, rice husks, and microbial agents. However, this method suffers from problems such as high cost of solidifying agents, environmental hazards, slow decomposition of straw and fertilizers, long decomposition cycles, secondary pollution from the solidifying agents themselves, and poor effectiveness of adding organic fertilizers. These issues prevent the effective utilization of the silt's inherent fertility, instead leading to increased costs, longer cycles, and secondary pollution. Furthermore, research in my country on directly using dredged silt as planting soil is limited. Currently, there is a lack of effective technologies to fully utilize the abundant nutrients in silt, reduce the increased costs associated with adding chemical fertilizers, and maximize the fertility of silt.

[0004] Electrochemical methods for treating sludge are a relatively new approach that offers advantages such as high efficiency, environmental friendliness, good controllability, cost-effectiveness, and speed. By applying an external electric field, the sludge undergoes a series of electrochemical reactions, altering its physicochemical properties. Currently, electrochemical methods for sludge treatment primarily focus on volume reduction and harmlessness, such as removing heavy metals and deep dehydration. However, they are rarely used to ultimately realize the resource utilization of sludge, such as modifying it for use as planting soil. Therefore, effective technologies for using electrochemical methods to improve dredged sludge for planting and enhance its fertility are currently lacking.

[0005] Patent document CN109258393A discloses a planting soil prepared from solidified silt and its application. This planting soil is made from the following raw materials in parts by weight: 70-85 parts silt, 5-12 parts silt solidifying agent, 1-3 parts lignin sulfonate, 2-5 parts potassium chloride, 3-10 parts wood ash, 2-6 parts calcium magnesium phosphate fertilizer, and 1-4 parts ammonium bicarbonate. The silt solidifying agent is prepared from various raw materials in parts by weight: 30-45 parts attapulgite, 30-40 parts modified diatomaceous earth, 2-8 parts magnesium oxide, 2-7 parts polyferric sulfate, 2-5 parts calcium chloride, 4-9 parts sodium silicate, 0.5-2 parts peroxide, 1-5 parts cationic chelate, 2-4 parts calcium hypochlorite, 1-3 parts chitosan, 1-2 parts hydroxypropyl methylcellulose, 2-3 parts modified starch, and 1-7 parts polyacrylamide. The final planting soil shows good results in vegetation planting. However, this technical solution involves numerous raw materials and a relatively complex formulation. It focuses more on the treatment of sludge with a solidifying agent, which inevitably leads to some secondary pollution during the treatment process. It may also cause some sludge to harden and affect the subsequent growth of vegetation. In addition, the technology also adds an appropriate amount of fertilizer, which does not fully utilize the fertilization effect of the sludge itself.

[0006] Patent document CN113526822A discloses a method for on-site improvement of silt and silt-planting soil. The method involves dewatering dredged silt to a moisture content of less than 60%; mixing silt particles with a silt conditioner to obtain the silt-planting soil; the silt conditioner includes river sand, coconut coir, granulated branches, volcanic rock filter media, and a deodorizer; finally, the silt-planting soil is used on-site for landscaping. This method achieves rapid treatment and application of silt. However, it suffers from drawbacks such as the large variety of raw materials, high dosage, high cost, the need for silt dewatering equipment, and the risk of secondary pollution.

[0007] Given the shortcomings of current methods for improving planting soil with silt, it is necessary to improve them. Summary of the Invention

[0008] In view of this, the present invention proposes a method and electrochemical device for activating the fertilizer effect of dredged sludge from reservoirs, in order to solve the problems of secondary pollution, high treatment cost and insufficient activation of sludge fertilizer effect in the prior art.

[0009] The technical solution of this invention is implemented as follows:

[0010] In a first aspect, the present invention provides a method for activating the fertility of dredged silt from a reservoir, comprising the following steps:

[0011] S1. Add fertilizer activator to the sludge sample, adjust the pH to 4-7, stir and then add hydrogen peroxide solution to obtain the sludge to be treated.

[0012] S2. Set the voltage gradient of the electrolytic cell. By applying gradient voltage and current to the sludge to be treated, an electrochemical reaction is initiated to promote the oxidative decomposition of nutrients in the sludge.

[0013] S3. Test the main control indicators of the sludge. If the test is qualified, the reaction ends and the next step is carried out. If the test is unqualified, adjust the concentration of the added fertilizer activator and the electrochemical operation parameters according to the main control indicators, and continue the electrochemical reaction until the main control indicators are qualified.

[0014] S4. End the reaction, filter and collect the sludge, crush and homogenize it to obtain sludge with enhanced fertilizer effect.

[0015] Based on the above technical solutions, preferably, the fertilizer effect activator includes retinoic acid solution and sodium sulfate solution, and the mass-volume ratio of the sludge sample, retinoic acid solution, sodium sulfate solution and hydrogen peroxide solution is (60-90)g:(10-16)mL:(12-18)mL:(10-16)mL.

[0016] Based on the above technical solutions, preferably, the A acid solution includes one or more combinations of tartaric acid, carotene, succinic acid, oxalic acid, sorbic acid, lactic acid, citric acid and maleic acid.

[0017] Based on the above technical solutions, preferably, the mass concentration of the A acid solution is 5% to 15%, the concentration of the sodium sulfate solution is 0.2 to 0.8 mol / L, and the mass concentration of the hydrogen peroxide solution is 30% to 40%.

[0018] Based on the above technical solution, preferably, step S2 further includes: after the electrochemical reaction has been going on for a period of time, the electrolyte after the reaction is collected in a storage tank by filtration, the pH is adjusted to 8-9, filtered, and returned to the electrolytic cell to realize the recycling of the electrolyte.

[0019] Based on the above technical solution, preferably, in step S2, a sodium carbonate solution is used to adjust the acidity or alkalinity of the electrolyte after the reaction, wherein the mass concentration of the sodium carbonate solution is 15% to 20% and the pH value of the sodium carbonate solution is 8 to 12.

[0020] Based on the above technical solutions, preferably, the main control indicators include a first main control indicator parameter, a second main control indicator parameter, and a third main control indicator parameter, and the detection and control of the first main control indicator parameter, the second main control indicator parameter, and the third main control indicator parameter can be controlled in a sequential manner or simultaneously.

[0021] Based on the above technical solutions, preferably, the first key control parameters include heavy metals and pH; the second key control parameters include available phosphorus, available potassium, hydrolyzable nitrogen, soluble salt concentration, cation exchange capacity, and organic matter; and the third key control parameters include moisture content, bulk density, and infiltration rate.

[0022] Based on the above technical solutions, preferably, the voltage gradient of the electrolytic cell is 3 to 6 V / cm.

[0023] Secondly, the present invention provides an electrochemical apparatus for activating the fertilizer effect of dredged sludge in a reservoir as described above, comprising an electrolytic cell, a water pump, a storage tank, and a reflux pump.

[0024] The electrolytic cell is used for electrochemical reactions of sludge samples;

[0025] The water pump is connected to the bottom of the electrolytic cell and is used to extract the electrolyte after the reaction.

[0026] One end of the storage tank is connected to a water pump, and the other end is connected to a reflux pump. The storage tank is used to adjust the acidity or alkalinity of the electrolyte after the reaction.

[0027] The reflux pump is connected to the top of the electrolytic cell and is used to return the adjusted electrolyte to the electrolytic cell for recycling.

[0028] Based on the above technical solutions, preferably, a filter screen is provided inside the electrolytic cell.

[0029] The filter screen is arranged perpendicular to the height of the electrolytic cell, dividing the electrolytic cell into a sludge zone and a cathode zone.

[0030] The sludge zone is used to place sludge samples for electrochemical reactions;

[0031] The cathode area is located below the sludge area and is used to filter and collect the electrolyte after the reaction.

[0032] Based on the above technical solutions, preferably, the sludge zone is equipped with a cathode plate, an anode plate, and a slide rail.

[0033] The slide rail is disposed on the inner wall of the electrolytic cell.

[0034] The anode plate and cathode plate are connected to the slide rail at both ends, and the anode plate and cathode plate can slide up and down along the slide rail in the silt area.

[0035] Based on the above technical solutions, preferably, the cathode is a planar mesh porous titanium electrode with a porosity of 30-50%; the anode is a porous titanium-based ruthenium-iridium coated electrode with a porosity of 15-45%, and the anode plate is covered with a stainless steel mesh.

[0036] The method and electrochemical device for activating the fertilizer effect of reservoir dredging sludge according to the present invention have the following advantages over the prior art:

[0037] (1) By adding fertilizer activator and electrochemical reaction, the release of nutrients and desorption of heavy metals in sludge can be effectively activated, thereby improving the treatment efficiency. At the same time, the electrolysis process and the heat generated during the electrolysis process can also eliminate toxic and harmful microorganisms in sludge to a certain extent, further promoting the activation of fertilizer effect of reservoir sludge. Meanwhile, the treatment process is simple, the raw material ratio is small, and the electrolyte is recycled after treatment, which can avoid secondary pollution.

[0038] (2) In this invention, a fertilizer activator is prepared by using tretinoin and sodium sulfate solution. Tretinoin can destroy sludge flocs and promote the desorption of metal ions from the flocs. Sodium sulfate can increase the conductivity of sludge and accelerate the electrolysis reaction. The combined action of tretinoin and sodium sulfate can promote the rapid desorption of metal ions from sludge and form a complex with tretinoin. The complex moves to the cathode area through electromigration. The water in the sludge can flow into the cathode area through electroosmosis, thereby reducing the water content and removing heavy metals.

[0039] (3) Based on the detection of the main control index parameters of dredged sludge, this invention determines the appropriate parameter range of each index parameter by decomposing the sludge index parameters, thereby judging the fertility status of the sludge and whether it can be used as greening planting soil. According to the scientific and reasonable electrochemical treatment process control, it solves the problem that dredged sludge is difficult to use as greening planting soil. The electrochemical method fully stimulates the fertility of the sludge and solves the problem of resource disposal of some sludge, which has certain economic, social and environmental benefits.

[0040] (4) Compared with traditional electrochemical reaction devices, the present invention allows the electrodes to be placed horizontally on a pre-set slide rail. During the electrolysis reaction, the sludge will collapse downwards. At this time, due to the sliding action of the electrodes on the slide rail, the electrodes slide downwards and further contact the sludge to maintain the good progress of the electrochemical reaction. Due to the horizontal placement of the electrodes, the rate of downward electromigration and electroosmosis of the sludge under the action of gravity is further increased. Both the anode and cathode will generate bubbles during the electrolysis process, which will be discharged through the pores of the porous electrode. Due to the migration of ions and water, some pores will appear in the sludge, and the contact area between the electrode and the sludge will decrease, resulting in a decrease in the reaction rate. At this time, due to the downward gravity of the sludge, the gaps between the sludge and the electrode will be re-compacted, preventing the impact of the reduced contact area as the reaction proceeds.

[0041] (5) In addition, the electrolyte after the reaction enters the cathode area and is recycled after treatment. This not only makes good use of the strong activity of the electrolyte, further promoting the release of nutrients from the sludge and stimulating the fertilizer effect of the sludge, but also effectively saves the amount of fertilizer stimulant added. Attached Figure Description

[0042] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the electrochemical device of the present invention;

[0044] Figure 2 This is a plan view of the electrolytic cell of the present invention.

[0045] Figure 3 This is a perspective view of the electrolytic cell of the present invention;

[0046] Figure 4 This is a top view of the slide rail of the present invention;

[0047] Figure 5 This is a flowchart of the method for activating the fertilizer effect of dredged silt in reservoirs according to the present invention.

[0048] Figure label:

[0049] 1. Electrolytic cell; 2. Water pump; 3. Storage tank; 4. Reflux pump; 5. Agitator; 6. Power supply; 11. Cathode plate; 12. Anode plate; 13. Slide rail; 14. Filter screen; 101. Sludge zone; 102. Cathode zone; 103. Vent; 31. First storage tank; 32. Second storage tank. Detailed Implementation

[0050] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0051] like Figure 1-4 As shown, the present invention provides an electrochemical device for activating the fertilizer effect of dredged sludge in reservoirs, comprising an electrolytic cell 1, a water pump 2, a storage tank 3, and a reflux pump 4. The electrolytic cell 1 is used to perform an electrochemical reaction on the sludge sample; the water pump 2 is connected to the bottom of the electrolytic cell 1 and is used to extract the electrolyte after the reaction; one end of the storage tank 3 is connected to the water pump 2, and the other end is connected to the reflux pump 4. The storage tank 3 is used to adjust the acidity or alkalinity of the electrolyte after the reaction; the reflux pump 4 is connected to the top of the electrolytic cell 1 and is used to return the adjusted electrolyte to the electrolytic cell 1 for recycling. During use, the sludge sample undergoes an electrochemical reaction in the electrolytic cell 1. The resulting electrolyte is filtered to the bottom of the electrolytic cell 1. Under the action of the water pump 2, the electrolyte is pumped to the storage tank 3 to adjust the acidity and alkalinity of the electrolyte, thereby filtering out heavy metals and impurities. Under the action of the return pump 4, the treated electrolyte is returned to the electrolytic cell 1, thus realizing the recycling of the electrolyte. This improves the utilization rate of the electrolyte, minimizes waste and loss of the electrolyte, and reduces the cost of sludge treatment.

[0052] In a preferred embodiment, a filter screen 14 is provided inside the electrolytic cell 1. The filter screen 14 is positioned perpendicular to the height direction of the electrolytic cell 1, and its shape is adapted to the cross-sectional shape of the electrolytic cell 1. The filter screen 14 divides the electrolytic cell 1 into a sludge zone 101 and a cathode zone 102. The sludge zone 101 is used to hold sludge samples for electrochemical reactions. The cathode zone 102 is located below the sludge zone 101 and is used to filter and collect the electrolyte after the reaction. The cathode zone 102 is connected to a water pump 2 to discharge the electrolyte collected in the cathode zone 102 into a storage tank 3. The filter screen 14 is made of stainless steel, and its pore size is 150-250 mesh. By setting a filter screen 14 below the sludge zone 101, the sludge can be blocked from entering the cathode zone 102. The pore size of the filter screen 14 is limited to 150-250 mesh, which ensures that the fertilizer activator solution after the reaction in the sludge zone 101 is filtered through the filter screen 14 into the cathode zone 102, and the sludge will not enter the cathode zone 102 on a large scale due to gravity. At the same time, it can also support the cathode plate 11, so that the cathode zone 102 can store more electrolyte.

[0053] Furthermore, the inner wall of the electrolytic cell 1 at the end of the cathode region 102 near the sludge region 101 is provided with several vent holes 103 to allow gases generated during the electrochemical reaction process to be discharged from the electrolytic cell 1. Therefore, during the reaction process, the electrolyte level in the cathode region 102 must be kept below the height of the vent holes 103.

[0054] In a preferred embodiment, a cathode plate 11, an anode plate 12, and a slide rail 13 are provided within the sludge zone 101. The slide rail 13 is disposed on the inner wall of the electrolytic cell 1, perpendicular to the bottom of the electrolytic cell 1, and arranged along the height direction of the electrolytic cell 1. The length of the slide rail 13 does not exceed the height of the sludge zone 101. Two slide rails 13 are provided, arranged parallel to each other. The two ends of the anode plate 12 and the cathode plate 11 are respectively connected to the two slide rails 13, and the shapes of their ends are adapted to the slide rails 13 so that the anode plate 12 and the cathode plate 11 can slide up and down within the sludge zone 101 along the slide rails 13. The cathode plate 11 is located at the bottom of the slide rail 13. The outermost contact surface of the slide rail 13 is circular to reduce the friction generated with the electrode during sliding, making the electrode slide more smoothly and reducing damage to the electrode.

[0055] During the reaction, as the sludge electrolyzes, it collapses downwards due to gravity. Simultaneously, the anode plate 12 slides downwards on the slide rail 13, further contacting the sludge and maintaining proper electrochemical reaction. In existing technologies, electrodes are typically placed vertically within the electrolytic cell 1. During the electrochemical reaction, heavy metal migration, electroosmotic dehydration, and oxidative decomposition of nutrients in the sludge cause the formation of pores between the sludge and the electrodes, reducing the contact area. This significantly affects the reaction rate and the control of current and voltage. In this invention, both the anode plate 12 and the cathode plate 11 are placed perpendicular to the height of the electrolytic cell 1 (i.e., horizontally within the cell). The anode plate 12 can slide up and down within the cell, further compacting the pores due to gravity during the electrochemical reaction. This prevents the reduction of the contact area between the sludge and the electrodes, allowing the sludge to undergo a more stable electrochemical reaction and increasing the reaction rate.

[0056] In a preferred embodiment, the cathode plate 11 is a planar mesh porous titanium electrode with a porosity of 30-50%; the cathode plate 11 is a thin-layer electrode with a thickness of 0.8-1.2 mm. The anode plate 12 is a porous titanium-based ruthenium-iridium coated electrode with a porosity of 15-45%; the anode plate 12 is a thin-layer electrode with a thickness of 0.8-1.2 mm. Both the cathode plate 11 and the anode plate 12 are porous electrode structures, which can increase the contact area between the electrode and the sludge, and the porous electrode facilitates the entry and exit of the electrolyte. The anode plate 12 is covered with a stainless steel mesh. During the electrolysis reaction, the stainless steel mesh causes iron ions to be generated at the anode. Under acidic conditions, these iron ions react with hydrogen peroxide to produce a strong oxidizing agent (·OH), which can oxidize and decompose the nutrients in the sludge into forms that are easily utilized by plants. At the same time, it also enhances the strength of the broken sludge flocs. As the nutrients begin to oxidize and decompose, nutrients such as nitrogen, phosphorus, and potassium in the sludge are released, and heavy metals are also desorbed, which is beneficial for subsequent removal.

[0057] In a preferred embodiment, the stirrer 5 and the power supply 6 are connected. The stirrer 5 is located inside the sludge zone 101 to mechanically stir the sludge, thereby promoting the full electrochemical reaction of the sludge. The power supply 6 is connected to the cathode plate 11 and the anode plate 12 respectively to carry out the electrochemical reaction.

[0058] Furthermore, the storage tank 3 includes a first storage tank 31 and a second storage tank 32. One end of the first storage tank 31 is connected to the water pump 2, and the other end is connected to the second storage tank 32. The other end of the second storage tank 32 is connected to the reflux pump 4. The first storage tank 31 is used to adjust the acidity or alkalinity of the electrolyte after the reaction, and then to filter out heavy metals and impurities from the electrolyte. The filtered electrolyte is then collected in the second storage tank 32.

[0059] Furthermore, the electrolytic cell 1, the water pump 2, the storage tank 3, and the reflux pump 4 are all connected by conduits. The conduits and the stirrer 5 are each provided with through holes at their connection points with the inner wall of the electrolytic cell 1. The outer diameter of the conduit is adapted to the diameter of the through hole in the inner wall of the electrolytic cell 1, and the rod of the stirrer 5 is adapted to the diameter of the through hole in the inner wall of the electrolytic cell 1. An anti-seepage material is provided at the connection points of the through holes to prevent the leakage of electrolyte in the cathode area 102 and the seepage of sludge in the sludge area 101.

[0060] like Figure 5 As shown, this invention provides a method for activating the fertility of dredged sludge from a reservoir, specifically including the following steps:

[0061] S1. Add fertilizer activator to the sludge sample, adjust the pH to 4-7, stir, and then add hydrogen peroxide solution to obtain the sludge to be treated.

[0062] Specifically, it also includes pre-treatment of sludge samples by filtering them to remove impurities such as garbage, stones and waste. The pre-treated sludge samples are then placed in electrolytic cell 1 for electrochemical reaction.

[0063] Furthermore, the fertilizer activator includes an retinoic acid solution and a sodium sulfate solution. The retinoic acid solution includes one or more combinations of tartaric acid, carotene, succinic acid, oxalic acid, sorbic acid, lactic acid, citric acid, and maleic acid. By adding retinoic acid and sodium sulfate solution to the sludge, the acidity of the retinoic acid not only adjusts the pH of the sludge but also breaks down the sludge flocs, allowing metal ions to desorb from the flocs. Simultaneously, the retinoic acid forms complexes with heavy metal ions, which migrate towards the cathode region 102 via electromigration. Water in the sludge flows into the cathode region 102 through electroosmosis, thus reducing water content and removing heavy metals. The addition of sodium sulfate solution significantly increases the conductivity of the sludge, accelerating the electrolysis reaction rate and improving the efficiency of the electrochemical reaction.

[0064] Furthermore, the mass-to-volume ratio of the sludge sample, retinoic acid solution, sodium sulfate solution, and hydrogen peroxide solution is (60-90) g : (10-16) mL : (12-18) mL : (10-16) mL. The mass concentration of the retinoic acid solution is 5%–15%, the concentration of the sodium sulfate solution is 0.2–0.8 mol / L, and the mass concentration of the hydrogen peroxide solution is 30%–40%. By further limiting the concentrations and amounts of the retinoic acid solution, sodium sulfate solution, and hydrogen peroxide solution, the sludge sample can be made to react more fully with the retinoic acid solution, sodium sulfate solution, and hydrogen peroxide solution, avoiding incomplete reaction of the sludge sample.

[0065] S2. Set the voltage gradient of electrolytic cell 1. By applying gradient voltage and current to the sludge to be treated, an electrochemical reaction is initiated to promote the oxidative decomposition of nutrients in the sludge.

[0066] Specifically, the total electrochemical reaction time is 60-80 hours. During the electrochemical reaction to activate the sludge fertilization effect, the voltage gradient between the cathode and anode of electrolytic cell 1 is set to 3-6 V / cm. For example, if the distance between the anode plate 12 and the cathode plate 11 is 10 cm, then the potential between the anode plate 12 and the cathode plate 11 is controlled to be 30-60 V.

[0067] Step S2 further includes: after 9-11 hours of electrochemical reaction, the electrolyte is collected by filtration into storage tank 3, the pH is adjusted to 8-9, filtered again, and returned to electrolytic cell 1 to achieve electrolyte recycling. Specifically, after every 9-11 hours of reaction, intermittent electrolyte recovery is performed in cathode zone 102. The reuse of the treated electrolyte in cathode zone 102 not only takes advantage of the high activity of the energized electrolyte to further promote the release of nutrients from the sludge and enhance its fertility, but also effectively saves on the amount of fertilizer activator added.

[0068] S3. Test the main control indicators of the sludge. If the test is qualified, the reaction ends and the next step is carried out. If the test is unqualified, adjust the concentration of the added fertilizer activator and the electrochemical operation parameters according to the main control indicators, and continue the electrochemical reaction until the main control indicators are qualified.

[0069] Specifically, the main control indicators include a first main control indicator parameter, a second main control indicator parameter, and a third main control indicator parameter. The first main control indicator parameter includes heavy metals and pH; the second main control indicator parameter includes available phosphorus, available potassium, hydrolyzable nitrogen, soluble salt concentration, cation exchange capacity, and organic matter; and the third main control indicator parameter includes moisture content, bulk density, and infiltration rate.

[0070] In one embodiment, the detection and control of the first, second, and third key control parameters are performed sequentially and step-by-step. Specifically, the sludge after the reaction is tested. First, the first key control parameter is tested. If it fails, adjustments are made using the concentration of the fertilizer activator and electrochemical operating parameters. If it passes, the second key control parameter is tested. If the second key control parameter fails, adjustments are made using the concentration of the fertilizer activator and electrochemical operating parameters. If the second key control parameter passes, the third key control parameter is tested. If it passes, the reaction ends; if it fails, adjustments are made using the concentration of the fertilizer activator and electrochemical operating parameters until the third key control parameter passes, at which point the reaction ends.

[0071] In another embodiment, the detection and control of the first, second, and third main control parameters are synchronized. That is, the sludge after the reaction is taken and the first, second, and third main control parameters are tested. If they are qualified, the reaction ends; if they are not qualified, the concentration of fertilizer activator and electrochemical operation parameters are adjusted until all main control parameters are qualified, then the reaction ends.

[0072] Furthermore, the qualification conditions for the first primary control indicator parameter include: heavy metal detection including cadmium, chromium, lead, arsenic, mercury, and nickel, with total cadmium ≤ 0.4 mg / kg, total chromium ≤ 100 mg / kg, total lead ≤ 85 mg / kg, total arsenic ≤ 30 mg / kg, total mercury ≤ 0.4 mg / kg, and total nickel ≤ 40 mg / kg; pH value 5.2–6.8. The qualification conditions for the second primary control indicator parameter include: available phosphorus 5-60 mg / kg, available potassium 60-300 mg / kg, hydrolyzable nitrogen 40-200 mg / kg, soluble salt concentration 0.4-0.9 ms / cm, cation exchange capacity greater than 10 cmol / kg, and organic matter 20-80 g / kg. The qualification conditions for the third primary control indicator parameter include: moisture content 30%–40%, and bulk density 1–2 g / cm³. 3 and infiltration rate ≥10mm / h.

[0073] S4. End the reaction, filter and collect the sludge, crush and homogenize it to obtain sludge with enhanced fertilizer effect. During the sludge filtration and collection, the filtrate is collected again in storage tank 3, the pH is adjusted to 8-9, filtered, and returned to electrolytic cell 1 to achieve the recycling of electrolyte.

[0074] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0075] Example 1

[0076] This embodiment provides a method for activating the fertility of dredged sludge from a reservoir, including the following steps:

[0077] S1. Take 800g of dredged sludge sample from the reservoir. Testing revealed the following key performance indicators for the dredged sludge before treatment: pH 7.42, moisture content 65%, and bulk density 1.07g / cm³. 3 The concentrations of heavy metals (total cadmium 3.4770 mg / kg, total chromium 45.3746 mg / kg, total lead 25.4112 mg / kg, total arsenic 0.5632 mg / kg, total mercury 0.2685 mg / kg, total nickel 28.126 mg / kg), available phosphorus 28.8 mg / kg, available potassium 46.1 mg / kg, hydrolyzable nitrogen 147.6 mg / kg, organic matter 36 mg / kg, infiltration rate 4.65 mm / h, cation exchange capacity 13 cmol / kg, and soluble salt concentration 0.53 mS / cm were measured. Pre-treated (garbage sorting, removal of stones and waste) reservoir dredging sludge was placed in electrolytic cell 1.

[0078] S2. Add 140 mL of 8% A acid solution (a mixture of citric acid, oxalic acid, and maleic acid in a mass ratio of 6:3:1) and 160 mL of 0.35 mol / L sodium sulfate solution to the sludge, adjust the pH to 5.9, stir, then add 140 mL of 35% hydrogen peroxide solution and continue stirring to obtain the sludge to be treated.

[0079] S3. Anode plate 12 is connected to the positive terminal of DC power supply 6, and cathode plate 11 is connected to the negative terminal of DC power supply 6. The potential between the anode and cathode is controlled to be 5V / cm, and the electrochemical reaction is started to stir the sludge.

[0080] S4. After 10 hours of reaction, turn on water pump 2 to extract the cathode electrolyte from cathode zone 102 and transfer it into the first electrolyte storage tank 31. Add a 15% sodium carbonate solution to adjust the pH of the cathode electrolyte to 9. After complete precipitation, transfer the filtered filtrate into the second storage tank 32. Turn on reflux pump 4 to return the electrolyte from the second storage tank 32 back into the reactor. After the reflux is complete, turn off the water pump and continue the electrochemical reaction. Intermittent electrolyte reuse is performed every 10 hours.

[0081] S5. After electrolysis for 80 hours, take 10g of sludge and divide it into several portions for testing of the main control indicators. If the test results are not up to standard, adjust the reaction conditions such as the concentration of fertilizer activator and voltage gradient to continue the electrochemical reaction.

[0082] S6. After the control indicators meet the standards, the sludge is collected by filtration, added to a crusher for crushing and homogenization, and finally obtained sludge with enhanced fertilizer effect.

[0083] After processing according to the method in Example 1 above, the detection results of step S5 are: pH 5.9, water content 37%, and bulk density 1.14 g / cm³. 3 The concentrations of heavy metals (total cadmium 0.23 mg / kg, total chromium 34.457 mg / kg, total lead 19.327 mg / kg, total arsenic 0.5564 mg / kg, total mercury 0.2614 mg / kg, total nickel 15.759 mg / kg), available phosphorus 51.3 mg / kg, available potassium 184.7 mg / kg, hydrolyzable nitrogen 182.5 mg / kg, organic matter 28 mg / kg, infiltration rate 6.82 mm / h, cation exchange capacity 17 cmol / kg, and soluble salt concentration 0.75 mS / cm were measured. Available phosphorus, readily available potassium, hydrolyzable nitrogen, and other nutrients were all increased to some extent, while the contents of six heavy metal ions were significantly reduced. The organic matter content decreased slightly during the reaction, which may be related to the oxidation and decomposition of organic matter into other nutrients that are easily absorbed by plants during the electrochemical activation process. The test results meet the requirements of "Greening Planting Soil" (CJ / T 340-2016) and can be directly used as greening planting soil.

[0084] Example 2

[0085] S1. Take 800g of dredged sludge sample from the reservoir. Testing revealed the following key performance indicators for the dredged sludge before treatment: pH 7.42, moisture content 65%, and bulk density 1.07g / cm³. 3 The concentrations of heavy metals (total cadmium 3.4770 mg / kg, total chromium 45.3746 mg / kg, total lead 25.4112 mg / kg, total arsenic 0.5632 mg / kg, total mercury 0.2685 mg / kg, total nickel 28.126 mg / kg), available phosphorus 28.8 mg / kg, available potassium 46.1 mg / kg, hydrolyzable nitrogen 147.6 mg / kg, organic matter 36 mg / kg, infiltration rate 4.65 mm / h, cation exchange capacity 13 cmol / kg, and soluble salt concentration 0.53 mS / cm were measured. Pre-treated (garbage sorting, removal of stones and waste) reservoir dredging sludge was placed in electrolytic cell 1.

[0086] S2. Add 100 mL of 5% acetic acid solution (a mixture of citric acid, oxalic acid, and maleic acid in a mass ratio of 6:3:1) and 120 mL of 0.2 mol / L sodium sulfate solution to the sludge, adjust the pH to 5.9, stir, then add 100 mL of 30% hydrogen peroxide solution and continue stirring to obtain the sludge to be treated.

[0087] S3. Anode plate 12 is connected to the positive terminal of DC power supply 6, and cathode plate 11 is connected to the negative terminal of DC power supply 6. The potential between the anode and cathode is controlled to be 3V / cm, and the electrochemical reaction is started to stir the sludge.

[0088] S4. After 10 hours of reaction, turn on water pump 2 to extract the cathode electrolyte from cathode zone 102 and transfer it to the first electrolyte storage tank 31. Add a sodium carbonate solution with a mass concentration of 18% to adjust the pH of the cathode electrolyte to 8. After complete precipitation, transfer the filtered filtrate to the second storage tank 32. Turn on reflux pump 4 to return the electrolyte from the second storage tank 32 back into the reactor. After the reflux is complete, turn off the water pump and continue the electrochemical reaction. Intermittent electrolyte reuse is performed every 10 hours.

[0089] S5. After electrolysis for 80 hours, take 10g of sludge and divide it into several portions for testing of the main control indicators. If the test results are not up to standard, adjust the reaction conditions such as the concentration of fertilizer activator and voltage gradient to continue the electrochemical reaction.

[0090] S6. After the control indicators meet the standards, the sludge is collected by filtration, added to a crusher for crushing and homogenization, and finally obtained sludge with enhanced fertilizer effect.

[0091] After processing according to the method in Example 2 above, the detection results of step S5 are: pH 6.1, water content 39%, and bulk density 1.11 g / cm³. 3 The concentrations of heavy metals (total cadmium 0.28 mg / kg, total chromium 41.234 mg / kg, total lead 22.259 mg / kg, total arsenic 0.9145 mg / kg, total mercury 0.3046 mg / kg, total nickel 18.746 mg / kg), available phosphorus 52.7 mg / kg, available potassium 188.3 mg / kg, hydrolyzable nitrogen 184.7 mg / kg, organic matter 30 mg / kg, infiltration rate 7.53 mm / h, cation exchange capacity 15 cmol / kg, and soluble salt concentration 0.81 mS / cm were measured. Available phosphorus, readily available potassium, hydrolyzable nitrogen, and other nutrients were all increased to some extent, while the contents of six heavy metal ions were significantly reduced. The organic matter content decreased slightly during the reaction, which may be related to the oxidation and decomposition of organic matter into other nutrients that are easily absorbed by plants during the electrochemical activation process. The test results meet the requirements of "Greening Planting Soil" (CJ / T 340-2016) and can be directly used as greening planting soil.

[0092] Example 3

[0093] S1. Take 800g of dredged sludge sample from the reservoir. Testing revealed the following key performance indicators for the dredged sludge before treatment: pH 7.42, moisture content 65%, and bulk density 1.07g / cm³. 3 The concentrations of heavy metals (total cadmium 3.4770 mg / kg, total chromium 45.3746 mg / kg, total lead 25.4112 mg / kg, total arsenic 0.5632 mg / kg, total mercury 0.2685 mg / kg, total nickel 28.126 mg / kg), available phosphorus 28.8 mg / kg, available potassium 46.1 mg / kg, hydrolyzable nitrogen 147.6 mg / kg, organic matter 36 mg / kg, infiltration rate 4.65 mm / h, cation exchange capacity 13 cmol / kg, and soluble salt concentration 0.53 mS / cm were measured. Pre-treated (garbage sorting, removal of stones and waste) reservoir dredging sludge was placed in electrolytic cell 1.

[0094] S2. Add 160 mL of 15% acetic acid solution (a mixture of citric acid, oxalic acid, and maleic acid in a mass ratio of 6:3:1) and 180 mL of 0.8 mol / L sodium sulfate solution to the sludge, adjust the pH to 5.9, stir, then add 160 mL of 40% hydrogen peroxide solution and continue stirring to obtain the sludge to be treated.

[0095] S3. Anode plate 12 is connected to the positive terminal of DC power supply 6, and cathode plate 11 is connected to the negative terminal of DC power supply 6. The potential between the anode and cathode is controlled to be 6V / cm, and the electrochemical reaction is started to stir the sludge.

[0096] S4. After 10 hours of reaction, turn on water pump 2 to extract the cathodic electrolyte from cathode zone 102 and transfer it to the first electrolyte storage tank 31. Add a 20% sodium carbonate solution to adjust the pH of the cathodic electrolyte to 12. After complete precipitation, transfer the filtered filtrate to the second storage tank 32. Turn on reflux pump 4 to return the electrolyte from the second storage tank 32 back into the reactor. After the reflux is complete, turn off the water pump and continue the electrochemical reaction. Intermittent electrolyte reuse is performed every 10 hours.

[0097] S5. After electrolysis for 80 hours, take 10g of sludge and divide it into several portions for testing of the main control indicators. If the test results are not up to standard, adjust the reaction conditions such as the concentration of fertilizer activator and voltage gradient to continue the electrochemical reaction.

[0098] S6. After the control indicators meet the standards, the sludge is collected by filtration, added to a crusher for crushing and homogenization, and finally obtained sludge with enhanced fertilizer effect.

[0099] After processing according to the method in Example 3 above, the detection results of step S5 are: pH 5.2, moisture content 38%, and bulk density 1.09 g / cm³. 3 The concentrations of heavy metals (total cadmium 0.21 mg / kg, total chromium 35.128 mg / kg, total lead 18.742 mg / kg, total arsenic 0.5153 mg / kg, total mercury 0.2525 mg / kg, total nickel 16.012 mg / kg), available phosphorus 50.4 mg / kg, available potassium 183.9 mg / kg, hydrolyzable nitrogen 180.2 mg / kg, organic matter 28 mg / kg, infiltration rate 6.63 mm / h, cation exchange capacity 18 cmol / kg, and soluble salt concentration 0.72 mS / cm were measured. Available phosphorus, readily available potassium, hydrolyzable nitrogen, and other nutrients were all increased to some extent, while the contents of six heavy metal ions were significantly reduced. The organic matter content decreased slightly during the reaction, which may be related to the oxidation and decomposition of organic matter into other nutrients that are easily absorbed by plants during the electrochemical activation process. The test results meet the requirements of "Greening Planting Soil" (CJ / T 340-2016) and can be directly used as greening planting soil.

[0100] Example 4

[0101] This embodiment provides a method for activating the fertility of dredged silt from a reservoir. The silt sample used is from the same source as in Example 1, and all the main control indicators of the dredged silt before treatment are the same. The specific operating steps in this comparative example are the same as in Example 1, except that in step S2, the amount of acetic acid solution added is 100 ml, and the amount of sodium sulfate solution added is 180 ml.

[0102] After processing according to the method in Example 4 above, the detection results of step S5 are: pH 6.0, water content 39%, and bulk density 1.12 g / cm³. 3 The concentrations of heavy metals (total cadmium 0.29 mg / kg, total chromium 42.156 mg / kg, total lead 22.347 mg / kg, total arsenic 0.8456 mg / kg, total mercury 0.2748 mg / kg, total nickel 17.564 mg / kg), available phosphorus 50.48 mg / kg, available potassium 182.74 mg / kg, hydrolyzable nitrogen 183.79 mg / kg, organic matter 29 mg / kg, infiltration rate 6.91 mm / h, cation exchange capacity 17 cmol / kg, and soluble salt concentration 0.73 mS / cm were measured. Available phosphorus, readily available potassium, hydrolyzable nitrogen, and other nutrients were all increased to some extent, while the contents of six heavy metal ions were significantly reduced. The organic matter content decreased slightly during the reaction, which may be related to the oxidation and decomposition of organic matter into other nutrients that are easily absorbed by plants during the electrochemical activation process. The test results meet the requirements of "Greening Planting Soil" (CJ / T 340-2016) and can be directly used as greening planting soil.

[0103] Example 5

[0104] This embodiment provides a method for activating the fertility of dredged sludge from a reservoir. The sludge sample used is from the same source as in Example 1, and all key control indicators of the dredged sludge before treatment are the same. The specific operating steps in this comparative example are the same as in Example 1, except that in step S2, the amount of acetic acid solution added is 160 ml, and the amount of sodium sulfate solution added is 120 ml.

[0105] After processing according to the method in Example 5 above, the detection results of step S5 are: pH 5.9, water content 37%, and bulk density 1.14 g / cm³. 3 The concentrations of heavy metals (total cadmium 0.22 mg / kg, total chromium 32.189 mg / kg, total lead 16.458 mg / kg, total arsenic 0.4975 mg / kg, total mercury 0.2416 mg / kg, total nickel 15.234 mg / kg), available phosphorus 50.5 mg / kg, available potassium 183.4 mg / kg, hydrolyzable nitrogen 181.5 mg / kg, organic matter 27 mg / kg, infiltration rate 6.71 mm / h, cation exchange capacity 18 cmol / kg, and soluble salt concentration 0.74 mS / cm were measured. Available phosphorus, readily available potassium, hydrolyzable nitrogen, and other nutrients were all increased to some extent, while the contents of six heavy metal ions were significantly reduced. The organic matter content decreased slightly during the reaction, which may be related to the oxidation and decomposition of organic matter into other nutrients that are easily absorbed by plants during the electrochemical activation process. The test results meet the requirements of "Greening Planting Soil" (CJ / T 340-2016) and can be directly used as greening planting soil.

[0106] Comparative Example 1

[0107] This comparative example provides a method for activating the fertility of dredged sludge from a reservoir. The sludge sample used is from the same source as in Example 1, and all key control indicators of the dredged sludge before treatment are the same. The specific operating steps in this comparative example are the same as in Example 1, except that the electrolytic cell 1 is set up differently. The size and shape of the electrolytic cell 1 in this comparative example are the same as in Example 1, but the electrolytic cell 1 does not have a slide rail 13. The electrodes are placed vertically, and a 200-mesh stainless steel filter screen 14 is used to divide the area into a cathode zone 102 and a sludge zone 101. The sludge is placed in the sludge zone 101 between the cathode and anode. The connection method of the remaining equipment is the same as in Example 1.

[0108] After processing according to the method in Comparative Example 1 above, the detection results of step S5 are: pH 5.9, moisture content 52%, and bulk density 1.09 g / cm³. 3 The following concentrations were found: heavy metals (total cadmium 2.5871 mg / kg, total chromium 41.2354 mg / kg, total lead 24.1287 mg / kg, total arsenic 0.5596 mg / kg, total mercury 0.2678 mg / kg, total nickel 19.354 mg / kg), available phosphorus 31.2 mg / kg, available potassium 57.4 mg / kg, hydrolyzable nitrogen 156.7 mg / kg, organic matter 34 mg / kg, infiltration rate 5.11 mm / h, cation exchange capacity 13 cmol / kg, and soluble salt concentration 0.57 mS / cm. The test results did not meet the requirements of the "Greening Planting Soil" standard (CJ / T 340-2016).

[0109] Comparative Example 2

[0110] This comparative example provides a method for activating the fertility of dredged sludge from a reservoir. The sludge sample used is from the same source as in Example 1, and all the main control indicators of the dredged sludge before treatment are the same. The specific operating steps in this comparative example are the same as in Example 1, except that in step S2, 140 mL of an 8% tretinoin solution (a mixed solution of citric acid, oxalic acid, and maleic acid in a mass ratio of 6:3:1) and 160 mL of deionized water are added to the sludge.

[0111] After processing according to the method in Comparative Example 2 above, the detection results of step S5 are: pH 5.9, moisture content 58%, and bulk density 1.11 g / cm³. 3The following concentrations were found: heavy metals (total cadmium 2.2458 mg / kg, total chromium 43.3587 mg / kg, total lead 22.8749 mg / kg, total arsenic 0.5611 mg / kg, total mercury 0.2654 mg / kg, total nickel 22.421 mg / kg), available phosphorus 35.4 mg / kg, available potassium 56.2 mg / kg, hydrolyzable nitrogen 167.5 mg / kg, organic matter 42 mg / kg, infiltration rate 4.89 mm / h, cation exchange capacity 13 cmol / kg, and soluble salt concentration 0.55 mS / cm. The test results did not meet the requirements of the "Greening Planting Soil" standard (CJ / T 340-2016).

[0112] Comparative Example 3

[0113] This comparative example provides a method for activating the fertility of dredged sludge from a reservoir. The sludge sample used is from the same source as in Example 1, and all the main control indicators of the dredged sludge before treatment are the same. The specific operating steps in this comparative example are the same as in Example 1, except that in step S2, 140 mL of deionized water and 160 mL of 0.35 mol / L sodium sulfate solution are added to the sludge.

[0114] After processing according to the method in Comparative Example 2 above, the detection results of step S5 are: pH 6.1, moisture content 57%, and bulk density 1.08 g / cm³. 3 The following concentrations were found: heavy metals (total cadmium 2.6213 mg / kg, total chromium 46.2435 mg / kg, total lead 24.5612 mg / kg, total arsenic 0.5812 mg / kg, total mercury 0.2613 mg / kg, total nickel 23.516 mg / kg), available phosphorus 35.2 mg / kg, available potassium 56.7 mg / kg, hydrolyzable nitrogen 165.4 mg / kg, organic matter 43 mg / kg, infiltration rate 4.78 mm / h, cation exchange capacity 14 cmol / kg, and soluble salt concentration 0.57 mS / cm. The test results did not meet the requirements of the "Greening Planting Soil" standard (CJ / T 340-2016).

[0115] Experiment on the effect of planting in silt

[0116] After preparing silt using ordinary soil, untreated silt, methods described in Examples 1-5, and methods described in Comparative Examples 1-3, planting effect experiments were conducted using silt. 25cm × 15cm plastic flowerpots were used, and ryegrass seeds were sown manually over a 40-day period. Growth indicators of the grass seeds were measured during the planting period.

[0117]

[0118]

[0119] A comparison of Examples 1-3 reveals that, under the same electrolysis time, the addition of fertilizer activator, hydrogen peroxide, and electrochemical reaction operating parameters all affect the fertilizer activation effect of sludge. This may be because the above parameters affect the degree of electrochemical reaction on the sludge, thereby affecting the removal effect of heavy metals and other harmful substances in the sludge and the fertilizer activation effect.

[0120] A comparison of Examples 4-5 with Example 1 reveals that, under the same electrolysis time, adjusting the mass-volume ratio of the sludge sample, tretinoin solution, and sodium sulfate solution can affect the changes in key control parameters such as heavy metals in the sludge, thereby influencing the fertilization effect of the sludge.

[0121] Comparing Comparative Example 1 with Example 1, it can be found that when the reactor is placed upright, the electrochemical reaction of the sludge is limited under the same reaction time and operating parameters. During the treatment process, the voltage is difficult to control. It can be observed that the electrode and the sludge do not make sufficient contact during the reaction, and there are many gaps. The storage of electrolyte in cathode region 102 leads to concentration polarization. These may be the reasons for the decrease in reaction rate. Compared with Example 1, it was found that the improvement effect of nutrients such as available phosphorus, available potassium, and hydrolyzable nitrogen was not obvious when electrolyzing for the same time. This shows that the horizontal placement of the electrode has a positive effect on the reaction rate and the activation of sludge fertilization effect.

[0122] Comparing Comparative Examples 2 and 3 with Example 1, it can be found that without treatment with the fertilizer activator (A acid solution + sodium sulfate solution), the nutrient content did not increase significantly under the same electrolysis time. In the middle of the experimental treatment, the reaction phenomenon was not obvious, and the downward movement of the sludge was not obvious. This may be because the conductivity of the sludge is low, resulting in a low current density and thus a low reaction rate. This also reflects the positive effect of the activator (formulated fertilizer activator) on sludge treatment.

Claims

1. A method for activating the fertility of dredged silt from a reservoir, characterized in that: The device includes an electrochemical apparatus for activating the fertilizer effect of dredged sludge in reservoirs, comprising an electrolytic cell, a water pump, a storage tank, and a reflux pump. The electrolytic cell is used for electrochemical reactions of sludge samples; The water pump is connected to the bottom of the electrolytic cell and is used to extract the electrolyte after the reaction. One end of the storage tank is connected to a water pump, and the other end is connected to a reflux pump. The storage tank is used to adjust the acidity or alkalinity of the electrolyte after the reaction. The reflux pump is connected to the top of the electrolytic cell and is used to return the adjusted electrolyte to the electrolytic cell for recycling. The electrolytic cell is equipped with a filter screen, which is perpendicular to the height of the electrolytic cell. The filter screen divides the electrolytic cell into a sludge zone and a cathode zone. The sludge zone is used to place sludge samples for electrochemical reactions. The cathode zone is located below the sludge zone and is used to filter and collect the electrolyte after the reaction. The sludge zone is provided with a cathode plate, an anode plate, and a slide rail. The slide rail is set on the inner wall of the electrolytic cell, perpendicular to the bottom of the electrolytic cell and set along the height direction of the electrolytic cell. The length of the slide rail does not exceed the height of the sludge zone. The two ends of the anode plate and the cathode plate are respectively connected to the slide rail. The anode plate and the cathode plate can slide up and down along the slide rail in the sludge zone. The anode plate is covered with a stainless steel mesh. S1. Add fertilizer activator to sludge sample, adjust pH to 4-7, stir and add hydrogen peroxide solution to obtain sludge to be treated. S2. Set the voltage gradient of the electrolytic cell. By applying gradient voltage and current to the sludge to be treated, an electrochemical reaction is initiated to promote the oxidative decomposition of nutrients in the sludge. S3. Test the main control indicators of the sludge. If the test results are qualified, the reaction ends and the next step is initiated. If the test fails, adjust the concentration of the added fertilizer activator and the electrochemical operating parameters according to the main control indicators, and continue the electrochemical reaction until the main control indicators pass the test. S4. End the reaction, filter and collect the sludge, crush and homogenize it to obtain sludge with enhanced fertilizer effect. The fertilizer activator includes retinoic acid and sodium sulfate solution, and the mass-volume ratio of the sludge sample, retinoic acid, sodium sulfate solution and hydrogen peroxide solution is (60-90) g: (10-16) mL: (12-18) mL: (10-16) mL; The α-acid includes one or more combinations of tartaric acid, carotene, succinic acid, oxalic acid, sorbic acid, lactic acid, citric acid, and maleic acid. The mass concentration of the acetic acid solution is 5%~15%, the concentration of the sodium sulfate solution is 0.2~0.8 mol / L, and the mass concentration of the hydrogen peroxide solution is 30%~40%.

2. The method for activating the fertility of dredged silt from a reservoir as described in claim 1, characterized in that: Step S2 also includes: After the electrochemical reaction has been going on for a period of time, the electrolyte is collected by filtration into a storage tank, the pH is adjusted to 8-9, filtered, and returned to the electrolytic cell to achieve the recycling of the electrolyte.

3. The method for activating the fertility of dredged silt from a reservoir as described in claim 1, characterized in that: The main control indicators include a first main control indicator parameter, a second main control indicator parameter, and a third main control indicator parameter. The detection and control of the first main control indicator parameter, the second main control indicator parameter, and the third main control indicator parameter are distributed or controlled synchronously in sequence.

4. The method for activating the fertility of dredged silt from a reservoir as described in claim 3, characterized in that: The first key control parameters include heavy metals and pH; the second key control parameters include available phosphorus, available potassium, hydrolyzable nitrogen, soluble salt concentration, cation exchange capacity, and organic matter; the third key control parameters include moisture content, bulk density, and infiltration rate.

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