Treatment method for deep dewatering and solidification of river and lake sediment, cultivated soil and application

Abstract

The present application relates to the technical field of river and lake sediment treatment and disposal, and particularly relates to a river and lake sediment deep dewatering and solidification treatment method, a soil culture and application. The present application discloses a river and lake sediment deep dewatering and solidification treatment method, which comprises the following steps: S1. mixing to-be-treated river and lake sediment and a tea polyphenol ethanol solution; after the mixing is completed, screening and separation are performed to obtain a sediment mixture; S2. fully mixing and reacting the sediment mixture and a nitrogen and phosphorus solidifying agent; after the mixing is completed, filtration and dewatering treatment are performed to obtain dewatered sediment; and S3. drying the dewatered sediment to obtain dried sediment. The treatment method disclosed in the present application first destroys the stable flocculation structure in the sediment by using tea polyphenol ethanol, and then solidifies the easily migratable components in the sediment by using magnesium aluminum silicate, so that the environmental risks of direct utilization can be reduced, and the resource utilization of river and lake dredged sediment can be promoted.

Description

Technical Field

[0001] This invention relates to the technical field of river and lake sediment treatment and disposal, and in particular to a treatment method, cultivation soil and application of deep dewatering and synergistic solidification of river and lake sediment. Background Technology

[0002] With rapid industrialization and urbanization, large amounts of pollutants generated by human activities are directly or indirectly discharged into rivers and lakes, leading to the accumulation of nitrogen and phosphorus nutrients, heavy metals, and organic matter in these water bodies. These pollutants then accumulate on sediment particles through various physicochemical processes. When the environmental conditions at the water-sediment interface change, these pollutants are released from the sediments into the overlying water, causing secondary pollution. Environmental dredging is currently the most direct and effective means of treating polluted rivers and lakes both domestically and internationally. It can quickly remove pollutants from bottom sediments and effectively restore aquatic ecosystems. However, dredging projects generate large amounts of bottom sediment, and indiscriminate dumping of this sediment occupies significant land areas and releases pollutants. Therefore, it is necessary to efficiently reduce and stabilize river and lake bottom sediment to minimize the volume of sediment that can be disposed of and control pollutant migration.

[0003] Dredged sediment is rich in organic matter, nitrogen, phosphorus, potassium nutrients, silicon oxides, and other useful components, making it a potential resource pool. Traditional methods of disposing of dredged sediment, such as ocean dumping and sanitary landfill, have drawbacks including resource waste, high carbon emissions, and environmental pollution.

[0004] Dewatering and conditioning is the primary step in treating dredged sediment, effectively reducing its volume. Chemical conditioning technology, due to its high dewatering efficiency and simple operation, is widely used in numerous practical engineering cases. This process mainly utilizes the coagulation / flocculation effects of chemical agents such as aluminum salts, iron salts, and polyacrylamide to improve the dewatering performance of sediment, typically used to treat sediment with a high water content (>90%). However, coagulation / flocculation conditioning cannot completely destroy the sediment floc structure, resulting in insufficient release of bound water within the extracellular polymers. Therefore, it is ineffective for conditioning sediment with low water content (70-80%), making it difficult to achieve deep dewatering. Quicklime and cement can enhance deep dewatering, but the high dosage of these agents leads to excessive dry mud cake production, and the alkaline nature of the mud cake is detrimental to plant growth, increasing the cost of harmless sediment treatment, which does not meet development needs. Therefore, seeking efficient and harmless sediment dewatering methods has broad market application prospects and significant social and environmental benefits.

[0005] Therefore, it is necessary to propose a treatment method, cultivation soil, and application of deep dewatering and synergistic solidification of river and lake bottom sediments. Summary of the Invention

[0006] To overcome the shortcomings of existing technologies, this invention provides a treatment method, a cultivation soil, and an application for deep dewatering and synergistic solidification of river and lake sediment. The treatment method first uses tea polyphenol ethanol to destroy the stable floc structure in the sediment, and then uses magnesium aluminum silicate to solidify the easily migrating components in the sediment. This can reduce the environmental risks associated with direct utilization and promote the resource utilization of dredged river and lake sediment.

[0007] The technical solution adopted by this invention to solve its technical problem is:

[0008] The primary objective of this application is to provide a method for the deep dewatering and synergistic solidification of river and lake sediments, comprising the following steps:

[0009] S1. Mix the river and lake sediment to be treated with the tea polyphenol ethanol solution; after mixing, perform screening and separation to obtain a sediment mixture;

[0010] S2. The sediment mixture and nitrogen-phosphorus solidifying agent are thoroughly mixed and reacted. After mixing, the mixture is filtered and dehydrated to obtain dehydrated sediment.

[0011] S3. The dehydrated sediment is dried to obtain dried sediment.

[0012] Furthermore, in step S1, the water content of the river and lake sediment to be treated is 70-80%, and the organic matter content is 20-30%.

[0013] Furthermore, in step S1, the amount of tea polyphenol ethanol solution used is 20 to 30 times the dry basis mass of the river and lake sediment to be treated; the mass content of tea polyphenols in the tea polyphenol ethanol solution is 0.1% to 1.0%.

[0014] Furthermore, in step S1, the screening and separation involves passing the river and lake sediment to be treated through a sieve with a mesh size of 60-200 mm after the mixing is completed, to obtain a sediment mixture.

[0015] Furthermore, in step S2, the nitrogen-phosphorus curing agent is magnesium aluminum silicate; the amount of magnesium aluminum silicate used is 3-6% of the dry basis mass of the river and lake sediment to be treated.

[0016] Furthermore, in step S2, the thorough mixing involves mixing the sediment mixture and the nitrogen-phosphorus curing agent at a stirring speed of 100-200 rpm for 10-20 min; then mixing at a stirring speed of 50-100 rpm for 15-30 min; controlling the pH of the sediment to be between 8.5 and 9.0 during mixing; and allowing it to stand for 1-1.5 h after mixing.

[0017] Furthermore, in step S2, the filtration and dehydration process is performed by using a filter press.

[0018] Furthermore, in step S3, the water content of the dewatered sediment is less than 35%, and the TN and TP contents are 1000-1500 mg / L and 300-500 mg / L, respectively.

[0019] The second objective of this application is to provide curing soil, including the dried sediment obtained by the treatment method described above.

[0020] A third objective of this application is to provide the application of a maintenance soil for use as a cultivation soil for riverbank slope protection and greening.

[0021] The beneficial effects of this invention are:

[0022] 1. The treatment method described in this application utilizes a tea polyphenol ethanol solution to disrupt the hydration film on the surface of proteins in river and lake sediments. This allows the exposed hydrophilic groups of the proteins to bind with tea polyphenols, enhancing their hydrophobicity. This effectively disrupts and disperses the stable sediment floc structure, releasing bound water, odor substances, and nitrogen and phosphorus substances trapped within, thus improving the sediment dewatering performance. Simultaneously, the oxidation-reduction reaction and adsorption of tea polyphenols remove odor substances such as sulfur / amine compounds from the sediment, rapidly eliminating the sediment odor. Furthermore, some magnesium and aluminum ions released from magnesium aluminum silicate react with the released free nitrogen and phosphorus in the diluted sediment mixture to form insoluble crystals, promoting the agglomeration of sediment particles into a dense and hard cementitious solidified body. The adsorption of magnesium aluminum silicate itself solidifies the organic nitrogen and phosphorus in the sediment, effectively controlling the migration and release of nutrients in subsequent sediment applications.

[0023] 2. The treatment method described in this application results in riverbed sediment rich in plant nutrients such as carbon, nitrogen, and phosphorus after conditioning. Furthermore, the residual tea polyphenols and magnesium aluminum silicate in the treated sediment are non-toxic to organisms. The resulting dried sediment is suitable for plant growth and can be used as maintenance soil, reducing the preparation and transportation costs of ecological slope protection soil for river channels. In addition, using conditioned riverbed sediment to prepare ecological slope protection plant cultivation soil is a natural material that is sourced locally and utilized in situ, further reducing the transportation and disposal costs of dredged sediment. Attached Figure Description

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0025] Figure 1 This is a process flow diagram of the deep dewatering and synergistic solidification treatment method for river and lake sediments described in this application;

[0026] Figure 2This is a trend graph showing the change in moisture content of dehydrated sediment obtained by the treatment method in Example 1; wherein, the mass content of tea polyphenols in tea polyphenol ethanol is 0.5%, and the amount of magnesium aluminum silicate added is about 5% of the dry mass of the sediment to be treated.

[0027] Figure 3 This is a graph showing the TN and TP content in the dehydrated filtrate during the treatment method of Example 2; wherein, the mass content of tea polyphenols in tea polyphenol ethanol is 0.5%, and the amount of magnesium aluminum silicate curing agent added is approximately 5% of the dry mass of the sediment to be treated;

[0028] Figure 4 This is a growth diagram of tall fescue seeds grown in the dried sediment obtained by different curing agents in the processing method of Example 2. Detailed Implementation

[0029] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments. The content mentioned in the embodiments is not intended to limit the present invention.

[0030] As used herein, “and / or” includes all combinations of any and one or more of the associated listed items. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used herein, the singular forms “a,” “an,” “an,” and “the” are also intended to include the plural forms unless the context clearly indicates otherwise. Further understanding is needed; when used in this specification, “comprising” designates the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof.

[0031] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. Further understanding is that terms, such as those defined in common dictionaries, are interpreted in accordance with their meaning in the context of the relevant field and are not idealized or overly formal, unless expressly defined herein.

[0032] The exemplary invention described herein may suitably omit any one or more limiting elements, which are not specifically disclosed herein. Therefore, terms such as “comprising,” “including,” “containing,” etc., should be interpreted broadly and non-limitingly. Furthermore, the terminology used herein is for descriptive purposes without limitation, and it is unintentional to use terms that do not include any equivalent characteristics, but only to describe a portion of their characteristics; however, various modifications are possible within the scope of the invention according to the claims. Therefore, while the invention has been specifically disclosed through preferred embodiments and optional features, variations of the invention embodied by the modifications disclosed herein may be noted by those skilled in the art, and such modifications and variations are considered to be within the scope of the invention.

[0033] All raw materials or reagents used in the embodiments and comparative examples of this invention were purchased from mainstream manufacturers on the market. Those without specified manufacturers or concentrations are all analytical grade raw materials or reagents that are routinely available. There are no particular restrictions as long as they achieve the expected effect. The reaction vessels and rotary evaporators used in this embodiment were all purchased from major manufacturers on the market. There are no particular limitations as long as they achieve the expected effect. Where specific techniques or conditions are not specified in this embodiment, they should be performed in accordance with the techniques or conditions described in the literature in this field or according to the product instructions.

[0034] All chemical reagents used in this invention are industrial grade; for example, industrial tea polyphenols with a purity ≥ 98%, and industrial grade magnesium aluminum silicate with a purity ≥ 99.5%.

[0035] To more efficiently utilize the various useful components in dredged sediment, such as organic matter, nitrogen, phosphorus, potassium nutrients, and silicon oxides, the primary objective of this application is to provide a method for deep dewatering and synergistic solidification of river and lake sediment, comprising the following steps:

[0036] S1. Mix the river and lake sediment to be treated with the tea polyphenol ethanol solution; after mixing, perform screening and separation to obtain a sediment mixture;

[0037] S2. The sediment mixture and nitrogen-phosphorus solidifying agent are thoroughly mixed and reacted. After mixing, the mixture is filtered and dehydrated to obtain dehydrated sediment.

[0038] S3. The dehydrated sediment is dried to obtain dried sediment.

[0039] Therefore, by diluting the river and lake sediment with tea polyphenol ethanol solution, separating it by screening, and then solidifying it with nitrogen and phosphorus solidifying agents, the resulting dewatered sediment has a low water content, and the N and P are not easily migrated after solidification.

[0040] Specifically, in step S1, the river and lake sediment to be treated and the tea polyphenol ethanol solution are mixed; after mixing, they are separated to obtain a sediment mixture; the specific process is as follows: prepare the tea polyphenol ethanol solution, mix the tea polyphenol ethanol solution and the river and lake sediment to be treated by stirring, controlling the stirring speed at 300-400 rpm and the stirring time at 20-30 min; after mixing, pass the mixture through a sieve with a mesh size of 60-200 mm for separation to obtain a sediment mixture.

[0041] Therefore, by using tea polyphenol ethanol solution to disrupt the hydration film on the surface of proteins in river and lake sediments, the hydrophilic groups exposed by the proteins can bind with tea polyphenols to enhance hydrophobicity, thereby effectively disrupting and dispersing the stable sediment floc structure. This releases bound water, odor substances, and nitrogen and phosphorus substances trapped within the sediment from the river and lake sediments, improving the sediment dewatering performance.

[0042] Specifically, the water content of the river and lake sediment to be treated is 70-80%, and the organic matter content is 20-30%.

[0043] Specifically, the amount of tea polyphenol ethanol solution used is 20 to 30 times the dry weight of the river and lake sediment to be treated; the mass content of tea polyphenols in the tea polyphenol ethanol solution is 0.1% to 1.0%, and the mass content of ethanol is 99% to 99.9%.

[0044] It is understood that the amount of tea polyphenol ethanol solution used can be any value of 20 times, 25 times, 28 times, or 30 times the dry basis mass of the river and lake sediment to be treated, or can be selected from any of the above two value ranges.

[0045] It is understood that the tea polyphenol ethanol solution contains 0.1% tea polyphenols and 99.9% ethanol by mass; or the tea polyphenol ethanol solution contains 1.0% tea polyphenols and 99% ethanol by mass; or the tea polyphenol ethanol solution contains 0.5% tea polyphenols and 99.5% ethanol by mass. The specific tea polyphenol ethanol solution can be prepared by weighing and mixing the corresponding amounts of tea polyphenols and ethanol according to the aforementioned specific tea polyphenol and ethanol mass contents.

[0046] Therefore, through the above technical solution, after the sediment of the river and lake to be treated is diluted with tea polyphenol ethanol solution, the sediment flocs are fully dispersed, which can release some free nitrogen and phosphorus; moreover, the small odor molecules in the sediment of the river and lake to be treated will be removed or adsorbed under the action of tea polyphenols.

[0047] Specifically, in step S2, the sediment mixture and nitrogen-phosphorus solidifying agent are thoroughly mixed and reacted. After mixing, the mixture is filtered and dehydrated to obtain dehydrated sediment.

[0048] More specifically, the nitrogen-phosphorus curing agent is magnesium aluminum silicate; the amount of magnesium aluminum silicate used is 3-6% of the dry weight of the river and lake sediment to be treated. The thorough mixing involves mixing the sediment mixture and the nitrogen-phosphorus curing agent (magnesium aluminum silicate curing agent) at a stirring speed of 100-200 rpm for 10-20 minutes; then mixing again at a stirring speed of 50-100 rpm for 15-30 minutes; controlling the pH of the sediment within 8.5-9.0 during mixing; and allowing it to stand for 1-1.5 hours after mixing.

[0049] Specifically, in step S3, the water content of the dewatered sediment is less than 35%, and the TN and TP contents are 1000-1500 mg / L and 300-500 mg / L, respectively.

[0050] Therefore, through the above technical solution, using magnesium aluminum silicate curing agent, some of the released magnesium and aluminum ions react with the released free nitrogen and phosphorus in the diluted sediment mixture to form insoluble crystals, promoting the agglomeration of sediment particles to form a dense and hard cemented solidified body; by utilizing the adsorption effect of magnesium aluminum silicate itself, the organic nitrogen and phosphorus in the sediment are solidified, effectively controlling the migration and release of nutrients in the subsequent application of sediment.

[0051] For example, such as Figure 1 As shown, the treatment method for deep dewatering and synergistic solidification of river and lake bottom sediment mainly includes the following steps:

[0052] (1) First, the non-flowing river and lake sediment to be treated is transported to a sealed mixing device, a certain amount of tea polyphenol ethanol solution is added, and the mixture is rapidly diluted into a liquid mixture by an electric stirrer. The stirring speed is controlled at 300-400 rpm and the stirring time is 20-30 min; a liquid sediment mixture is obtained.

[0053] (2) The liquid sediment mixture is filtered with a screen aperture of 60-200 mm to remove the larger gravel and biological residues. The mixture is then transported to a landfill for treatment to obtain the filtered liquid sediment mixture.

[0054] (3) Add magnesium aluminum silicate as a nitrogen-phosphorus curing agent and mix it thoroughly with the filtered liquid sediment mixture. The mixing is divided into two stages. In the first stage, the mixture is rapidly mixed at a speed of 100-200 rpm for 10-20 min. In the second stage, the mixture is rapidly mixed at a speed of 50-100 rpm for 15-30 min. During the mixing, the pH of the sediment should be controlled within the range of 8.5-9.0. After the mixing is completed, the sediment should be allowed to stand for 1-1.5 h.

[0055] (4) The mixed sediment is fed into a plate and frame filter press to dewater the conditioned sediment. The pressure is controlled at 0.5-0.8 MPa. The dewatered sediment after filtration is placed in a well-ventilated and open area to dry for 2-3 days to obtain dry sediment.

[0056] (5) Use a crusher to crush large pieces of dry bottom mud to obtain ecological revetment green plant cultivation soil.

[0057] The tea polyphenol ethanol solution is prepared by adding solid tea polyphenols to industrial alcohol and stirring rapidly for 1 to 2 minutes, with a tea polyphenol content of 0.1% to 1.0%. The dosage of the tea polyphenol ethanol solution is 20 to 30 times the dry weight of the sediment to be treated. The dosage of magnesium aluminum silicate is 3 to 6% of the dry weight of the sediment to be treated.

[0058] The above-mentioned treatment method is particularly suitable for the deep dewatering of non-flowing river and lake sediments with a water content of 70-80%. This treatment method has the following advantages:

[0059] (1) Ethanol has an excellent dehydration effect on sediment in this state and does not increase the yield of dry sediment, which is an effect that deep dehydrating agents such as lime and quicklime cannot achieve.

[0060] (2) As the moisture content of the sediment increases (>85%), the dehydration effect of ethanol gradually deteriorates. Therefore, adding tea polyphenol solution alone for deodorization will affect the dehydration effect; and adding solid tea polyphenol alone is only suitable for deodorizing sediment with high moisture content.

[0061] (3) By utilizing the property of ethanol to destroy sediment flocs, the sediment flocs can be dispersed more quickly, and odorous substances and free nitrogen and phosphorus can be released, which is beneficial to the subsequent thorough mixing, solidification and deodorization of sediment.

[0062] (4) Tea polyphenols are easily soluble in ethanol. After diluting and conditioning the bottom mud with tea polyphenol ethanol solution, the tea polyphenols can be thoroughly mixed with the bottom mud along with the ethanol solution, and deodorize quickly and fully. This is something that cannot be achieved by simply adding solid tea polyphenols.

[0063] (5) Both ethanol and tea polyphenols are green chemical agents, and their residual content in the bottom sediment is basically harmless to the environment. Therefore, they are suitable for preparing ecological bank protection soil.

[0064] (6) It can significantly reduce the volume of bottom sediment and solidify nitrogen and phosphorus substances in the bottom sediment. The treated bottom sediment is suitable as a raw material for greening soil on river / lake embankment slopes.

[0065] The second objective of this application is to provide curing soil, including the dried sediment obtained by the treatment method described above.

[0066] The third objective of this application is to provide an application for a maintenance soil used as a cultivation soil for riverbank slope protection and vegetation. This application involves pulverizing dried sediment to create an ecological riverbank protection cultivation soil for use in river and lake slope greening and protection, thus opening up a new technical approach for the environmental remediation of open sediment storage sites and possessing significant economic, social, and environmental benefits.

[0067] Example 1

[0068] The treatment method for deep dewatering and synergistic solidification of river and lake bottom sediments mainly includes the following steps:

[0069] This embodiment uses riverbed sediment as the treatment object. The basic properties of the sediment are as follows: organic matter content is 27.7%, water content is 78.8%, and pH is 7.2.

[0070] Take approximately 50 kg of the above-mentioned sediment sample, and add tea polyphenol ethanol solution (e.g., based on different multiples of the dry weight of the sediment sample) to the solution. Figure 2 (As shown), the mixture was rapidly stirred for 25 minutes using an electric mixer at a speed of 300 rpm; the diluted bottom mud slurry was then filtered through an 80 mm sieve to separate large volumes of sand, gravel, and branches.

[0071] Industrial-grade calcium oxide, silicate cement, tricalcium silicate, and magnesium aluminum silicate were further added to the treated sediment mixture at 5% of the dry weight of the sediment. The mixture was rapidly stirred for 20 minutes at 150 rpm using an electric mixer to ensure thorough mixing. Then, the electric mixer speed was reduced to 80 rpm and the mixture was slowly stirred for 20 minutes to allow for sufficient reaction. The mixture was then allowed to stand for one hour. The settled sediment was then dewatered and solidified using a plate and frame filter press, and the moisture content of the dewatered sediment filter cake was measured. The results are as follows: Figure 2 As shown, when the dosage of tea polyphenol ethanol solution was 24 g / g TSS, the moisture content of the tea cake decreased to 31.4%.

[0072] Example 2

[0073] The treatment method for deep dewatering and synergistic solidification of river and lake bottom sediments mainly includes the following steps:

[0074] This embodiment uses riverbed sediment as the treatment object. The basic properties of the sediment are as follows: organic matter content is 27.7%, water content is 78.8%, and pH is 7.2.

[0075] Take approximately 50 kg of the above-mentioned sediment sample, add 24 times the dry weight of the sediment sample to a tea polyphenol ethanol solution, and stir rapidly for 25 minutes using an electric stirrer at a stirring speed of 300 rpm; filter the diluted sediment slurry through an 80 mm sieve to separate large volumes of sand, gravel and branches.

[0076] Industrial-grade calcium oxide, silicate cement, tricalcium silicate, and magnesium aluminum silicate were further added to the treated sediment mixture at 5% of the dry weight of the sediment. The mixture was then rapidly stirred for 20 minutes at 150 rpm using an electric mixer to ensure thorough mixing. Next, the electric mixer speed was reduced to 80 rpm and the mixture was slowly stirred for 20 minutes to allow for complete reaction. The mixture was then allowed to stand for one hour. The settled sediment was then dewatered and solidified using a plate and frame filter press. The TN and TP content in the dewatered filtrate was measured. Figure 3 The results showed that silicate cement treatment of sediment filtrate resulted in the lowest TP and TN content, followed by magnesium aluminum silicate, while calcium oxide and tricalcium silicate exhibited the worst curing effect.

[0077] like Figure 4 As shown, the obtained mud cakes were placed in an open area to dry for 3 days. Large pieces of mud cakes were then crushed using a crusher. The mud cakes were used to cultivate tall fescue seeds. The pot experiment lasted for 1 month. The results showed that, compared with other solidification treatment groups, magnesium aluminum silicate solidified mud showed a significant promoting effect on plant growth. The growth of tall fescue cultivated in the treated mud increased significantly by 47.1% compared with the control group.

[0078] The above embodiments are preferred implementations of the present invention. In addition, the present invention can be implemented in other ways. Any obvious substitutions without departing from the concept of the present invention are within the protection scope of the present invention.

Claims

1. A method for deep dewatering and synergistic solidification of river and lake bottom sediment, characterized in that, Includes the following steps: S1. Mix the river and lake sediment to be treated with the tea polyphenol ethanol solution; after mixing, screen and separate to obtain the sediment mixture; the tea polyphenol ethanol solution is prepared by adding solid tea polyphenols to industrial alcohol and stirring rapidly for 1-2 minutes. S2. The sediment mixture and nitrogen-phosphorus solidifying agent are thoroughly mixed and reacted. After mixing, the mixture is filtered and dehydrated to obtain dehydrated sediment. S3. The dehydrated sediment is dried to obtain dried sediment.

2. The processing method according to claim 1, characterized in that, In step S1, the water content of the river and lake sediment to be treated is 70-80%, and the organic matter content is 20-30%.

3. The processing method according to claim 1, characterized in that, In step S1, the amount of tea polyphenol ethanol solution used is 20 to 30 times the dry basis mass of the river and lake sediment to be treated; the mass content of tea polyphenols in the tea polyphenol ethanol solution is 0.1% to 1.0%.

4. The processing method according to claim 1, characterized in that, In step S1, the screening and separation involves passing the river and lake sediment to be treated through a sieve with a mesh size of 60-200 mm after mixing to obtain a sediment mixture.

5. The processing method according to claim 1, characterized in that, In step S2, the nitrogen-phosphorus curing agent is magnesium aluminum silicate; the amount of magnesium aluminum silicate used is 3-6% of the dry basis mass of the river and lake sediment to be treated.

6. The processing method according to claim 1, characterized in that, In step S2, the thorough mixing involves mixing the sediment mixture and the nitrogen-phosphorus curing agent at a stirring speed of 100-200 rpm for 10-20 min; then mixing at a stirring speed of 50-100 rpm for 15-30 min; controlling the pH of the sediment to be between 8.5 and 9.0 during mixing; and allowing it to stand for 1-1.5 h after mixing.

7. The processing method according to claim 1, characterized in that, In step S2, the filtration and dehydration process is performed by using a filter press.

8. The processing method according to claim 1, characterized in that, In step S3, the water content of the dewatered sediment is less than 35%, and the TN and TP contents are 1000~1500mg / L and 300~500mg / L, respectively.

9. Curing soil, characterized in that, The dried sediment obtained by the processing method according to any one of claims 1-8.

10. The application of curing soil, characterized in that, This includes using the maintenance soil described in claim 9 as a cultivation soil for riverbank slope protection and greening.

Images