A sediment locking agent for river and lake internal source pollution treatment, a preparation method and a treatment method

Abstract

The present application relates to the technical field of pollution control, and discloses a kind of for river and lake endogenous pollution control bottom mud locking agent and preparation method and treatment method, the preparation method of bottom mud locking agent for river and lake endogenous pollution control includes the following steps: S1: straw is ground to powder for standby;S2: part of straw powder is carbonized, and is prepared into straw biochar after acidification;S3: a certain amount of ferrous chloride and ferric chloride is weighed, added to deionized water, and stirred to form a first mixture;S4: ground straw and straw biomass charcoal are added to the first mixture in the above S3, and stirred to form a second mixture;The straw therein can provide carbon source for bottom mud microorganisms, which is conducive to the construction of the later ecosystem, and the use of bottom mud realizes the return of original microorganisms, trace elements and organic matter in bottom mud to the bottom mud ecological environment.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pollution control, in particular to a bottom sediment locking agent for internal source pollution control of rivers and lakes, a preparation method and a control method. BACKGROUND

[0002] Bottom sediment control plays a crucial role in the treatment of black and odorous water bodies. The bottom sediment of black and odorous water bodies continuously receives pollutants from the water body, becoming a repository of pollutants, thereby causing serious pollution. When the bottom sediment of the water body is disturbed, such as sudden changes in hydrodynamic conditions, ship navigation operations, wind disturbance, etc., the pollutants therein will be re-released into the water body, causing secondary pollution. If the release of pollutants in the bottom sediment of rivers and lakes cannot be effectively controlled, the internal source pollution caused thereby will become the main source of water pollution, and even if the amount of external source pollutants is effectively reduced, the environmental treatment of black and odorous water bodies will be difficult to achieve good results. Therefore, bottom sediment control plays a crucial role in the treatment of black and odorous water bodies.

[0003] At present, bottom sediment control can be divided into dredging and in-situ remediation. Dredging usually requires a large amount of mechanical equipment and manpower, and the bottom sediment dredged on shore needs a large treatment site for disposal, which has certain restrictions in actual application.

[0004] In-situ remediation of bottom sediment has a wide range of application requirements. In-situ remediation of bottom sediment can be mainly divided into two categories: one is biological method, which promotes the degradation of organic matter in bottom sediment by adding microbial preparations to the water body or bottom sediment; the other is chemical method, which reduces the release of pollutants in bottom sediment to water body by adding flocculating agents, or reduces the solubility, migration or toxicity of nitrogen, phosphorus, heavy metals and other pollutants by adding hardening agents and auxiliary agents such as lime, volcanic ash, cement, modified titanium dioxide, etc. to the bottom sediment. At present, some technologies combine biological method and chemical method to some extent.

[0005] However, the composition of the bottom sediment remediation agent of the prior art often needs to be prepared through complex processing, which is not convenient to use; the decomposition, sedimentation and reduction of pollutants in the bottom sediment of serious black and odorous water bodies are insufficient, and nitrogen, phosphorus, COD, heavy metals and other pollutants are easily released again to the water body; long-term treatment of bottom sediment with a large amount of strong oxidizing agent will cause continuous and rapid decomposition of macromolecular organic matter, generating a large amount of free nitrogen, phosphorus and heavy metals, causing excessive release of pollutants to the water body, further aggravating the black and odorous phenomenon of the water body and heavy metal ion pollution; the treated bottom sediment has low compactness and insufficient solidification, which is easy to turn over after being washed by water flow in the rainy season, causing secondary pollution; or the hardness of the treated bottom sediment is too high, and the carbon content of the bottom sediment is low, making it difficult to construct the ecological system in the later period. SUMMARY

[0006] The present application aims to provide a kind of for river and lake endogenous pollution treatment bottom mud locking agent and preparation method and treatment method, utilize the bottom mud locking agent in the present application on the basis of realizing the rapid locking of pollutant, provide basic carbon source and microorganism for the recovery of bottom mud, realize the self-recovery of bottom mud ecology.

[0007] The present application is realized by the following technical solutions.

[0008] A kind of for river and lake endogenous pollution treatment bottom mud locking agent preparation method of the present application, it include the following steps:

[0009] S1: straw is ground to powder for standby;

[0010] S2: part of straw powder is carbonized, and is prepared into straw biochar after acidification;

[0011] S3: the set amount of ferrous chloride and ferric chloride is weighed, added to deionized water, and stirred, to form the first mixture;

[0012] S4: after grinding, straw and straw biomass charcoal are added to the first mixture in the above S3, and are stirred, to form the second mixture;

[0013] S5: the pH of the second mixture in S4 is adjusted to 10 with alkaline solution, and is stirred;

[0014] S6: the second mixture after processing in S5 step is freeze-dried, and then ground into powder;

[0015] S7: the powder obtained in S6 step is mixed with air-dried bottom mud and ground, to prepare bottom mud locking agent.

[0016] Further, in S3 step, the mass ratio of ferrous chloride and ferric chloride is 1:3.

[0017] Further, in S3 step, the temperature of the stirring water bath is maintained at 80 DEG C.

[0018] Further, in S4 step, stirring at least 30 minutes.

[0019] Further, in S5 step, stirring at least 1 hour.

[0020] Further, in S7 step, ball milling is used, the ball milling speed is 180 revolutions / minute, and ball milling lasts at least 1 hour.

[0021] A kind of for river and lake endogenous pollution treatment bottom mud locking agent is made by the above-mentioned preparation method, including straw powder, straw biochar, ferrous chloride, ferric chloride and bottom mud.

[0022] A treatment method for river and lake internal source pollution treatment, comprising the following steps:

[0023] S1: sampling the sediment of the pollution area to be treated;

[0024] S2: performing structure analysis and basic physicochemical property analysis on the sediment to determine the sediment environment;

[0025] S3: determining the dosage of the sediment locking agent;

[0026] S4: adding the sediment locking agent into the pollution area to be treated;

[0027] S5: regularly detecting the sediment of the pollution area to be treated;

[0028] S6: adjusting the subsequent dosage of the sediment locking agent.

[0029] Further, in the S2 step, the analyzed sediment can be divided into a sediment environment with low organic carbon content, a sediment environment with high sediment pollutant concentration, and a sediment environment with poor sediment microbial species and quantity.

[0030] Further, in the S3 step, the sediment locking agent with a corresponding formula is added according to the sediment environment, and the sediment locking agent formula includes a straw-based sediment locking agent for the sediment environment with low organic carbon content, a magnetite and biochar-based sediment locking agent for the sediment environment with high sediment pollutant concentration, and a sediment-based sediment locking agent for the sediment environment with poor sediment microbial species and quantity.

[0031] Further, the following step is further included: S7: after the treatment of the pollution area is completed or during the treatment, the sediment locking agent shell adsorbed with pollutants can be separated from the sediment by magnetic attraction.

[0032] The present application has the following advantages:

[0033] The sediment locking agent contains straw and sediment components, realizes the recycling of waste resources, is simple to process, and has low cost. The straw in the sediment locking agent can provide a carbon source for sediment microorganisms, which is beneficial to the construction of the ecological system in the later period. The biomass charcoal and modified magnetite can adsorb and fix the pollutants in the sediment. The use of sediment realizes the return of the original microorganisms, trace elements and organic matter in the sediment to the sediment ecological environment. The concentration of ammonia nitrogen and total phosphorus in the sediment interstitial water is reduced. The presence of the modified magnetite enables the adsorbed pollutants to leave the sediment environment by magnetic attraction. The pollutants in the sediment are effectively isolated from the overlying water body. BRIEF DESCRIPTION OF DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the accompanying drawings needed to be used in the embodiments or prior art description will be briefly introduced. Obviously, the accompanying drawings in the following description are only some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without any creative effort.

[0035] The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0036] Figure 1 The treatment method flowchart for river and lake internal source pollution treatment;

[0037] Figure 2 The experimental result graph. DETAILED DESCRIPTION

[0038] The present application will be further described below in conjunction with the accompanying drawings and embodiments. Figures 1-2 The present application will be further described below in conjunction with the accompanying drawings and embodiments.

[0039] The present application relates to a kind of for river and lake internal source pollution treatment bottom mud locking agent, mainly by modified magnetite as main body, by adding modified straw, biochar and the bottom mud of ecological good river and lake dredging to magnetite is modified, generate a kind of for the locking agent of pollutant in bottom mud.

[0040] 1. Preparation method

[0041] (1) straw is ground to powder by grinder, for standby.

[0042] (2) part of straw powder is carbonized in carbonization equipment, and is prepared into straw biochar after acidification by drying, dry distillation, cooling and other processes.

[0043] (3) a certain amount of ferrous chloride and ferric chloride are added to deionized water, the temperature is maintained at 80-90 DEG C by water bath, and stirring is carried out by magnetic or mechanical stirring.

[0044] (4) ground straw and straw biomass charcoal are added to (3), and stirring is carried out for 30-60 minutes.

[0045] (5) the pH of (4) is adjusted to 10±0.5 by alkaline solution, and stirring is carried out for 1-2 hours, and the alkaline solution can use sodium hydroxide, and the modified magnetite (ferric oxide) containing straw and straw biomass charcoal is obtained by this step, and the synthesis ionic equation of ferric oxide is: Fe 2+ +2Fe 3+ +8OH - = Fe3O4 (colloid) + 4H2O.

[0046] (6) (5) is freeze-dried and ground into powder.

[0047] (7) Put (6) into the ball mill with air-dried sediment to ball mill, 180 revolutions per minute, 1 hour, to prepare the sediment locking agent.

[0048] According to the different sediment environment, the formula of the sediment locking agent can be divided into straw-based for the sediment environment with low organic carbon content in sediment, magnetite and biochar-based for the sediment environment with high pollutant concentration in sediment, and sediment-based for the sediment environment with poor microbial species and quantity in sediment. According to the experimental and practical application effect, the following three formulas are developed:

[0049]

[0050] The sediment locking agent can also be prepared according to the required amount of sediment locking agent in the above proportion, so as to obtain the sediment locking agent suitable for different sediment environments.

[0051] The sediment locking agent in the scheme is environmentally friendly and will not pollute the environment; the straw is added to the agent to realize the recycling of waste; the sediment is used to realize the resource utilization of dredged sediment, realize the return of original microorganisms, trace elements and organic matter in sediment to the sediment ecological environment; combined with the adsorption performance of modified magnetite and biochar, the concentration of ammonia nitrogen and total phosphorus in sediment interstitial water is significantly reduced; the presence of modified magnetite makes the adsorbed pollutants leave the sediment environment by magnetic attraction means. Effectively isolate the release of pollutants in the sediment to the overlying water body.

[0052] 2. Application

[0053] In the actual application process, different amounts of sediment locking agent are added according to the different water quality and sediment pollutant concentrations, such as Figure 1 , the specific process is as follows.

[0054] S1: Sampling the sediment of the pollution area to be treated;

[0055] S2: Structural analysis and basic physicochemical property analysis of the sediment to determine the sediment environment;

[0056] S3: Determine the type and amount of sediment locking agent, the amount can be determined according to the pollution degree, pollution area, pollution depth and other parameters in the sediment, this step is the preliminary determination of the amount of sediment locking agent;

[0057] S4: Put the sediment locking agent into the pollution area to be treated, and use automatic mechanical equipment or manual operation to evenly put it;

[0058] S5: Regularly detect the sediment in the pollution area to be treated, and detect the pollution control according to the parameters such as the content of pollutants (such as ammonia nitrogen, total phosphorus, arsenic, selenium, antimony, etc.), microorganisms, organic carbon, etc.

[0059] S6: If the pollutants and ecological indicators do not meet the standards, adjust the subsequent sediment locking agent dosage, and repeat steps S5 and S6 until the treatment is completed, and the sediment ecology is restored.

[0060] Optionally, it further comprises a step S7: After the treatment is completed or during the treatment, the magnetite adsorbing pollutants can leave the sediment environment through magnetic attraction means, such as Figure 1 This step can be performed before the sediment locking agent is added in step S6.

[0061] 3. Effects of each component

[0062] The sediment locking agent is mainly composed of sediment, straw, biochar, and modified magnetite.

[0063] Sediment: Provides original microorganisms, trace elements, and organic matter for sediment ecology.

[0064] Straw: Provides carbon source for sediment microorganisms; recycling of waste resources.

[0065] Biochar: Adsorption and fixation of sediment pollutants; recycling of waste resources.

[0066] Modified magnetite: Adsorption and fixation of sediment pollutants; separation of sediment pollutants from sediment.

[0067] 4. Effects

[0068] 4.1 Laboratory small test

[0069] 4.1.1 Batch experiment

[0070] 2g of sediment locking agent (Formula 1) was added to a 250mL three-necked flask containing 200mL of a certain concentration (1, 5, 10mg / L) of pollutant solution (ammonia nitrogen, ammonium chloride solid preparation; total phosphorus, potassium dihydrogen phosphate solid preparation; arsenic, sodium arsenite solid preparation; selenium, sodium selenite solid preparation; antimony, antimony trichloride solid preparation), and the pH was adjusted to 7.0±0.1 with hydrochloric acid and sodium hydroxide solution. The reaction was carried out under continuous mechanical stirring at 500r / min, and the temperature was 25±5℃. During the reaction, according to the pre-set sampling time, 1mL of reaction solution was taken out with a syringe, and after filtration with a 0.22μm filter, the water quality ammonia nitrogen and total phosphorus concentration were detected by ultraviolet spectrophotometer, and the water quality arsenic, selenium, and antimony concentration were detected by atomic fluorescence photometer. The experimental device and results are shown in Figure 2

[0071] The experimental results show that the sediment locking agent has good removal effect on ammonia nitrogen, total phosphorus, arsenic, selenium, and antimony in water, indicating that the sediment locking agent can effectively realize the locking effect of pollutants (nitrogen, phosphorus, heavy metals) in sediment.​

[0072] 4.2 Column experiment

[0073] In order to further verify the locking effect of the bottom sediment locking agent on the pollutants in the bottom sediment, the performance of the bottom sediment locking agent is evaluated by column experiment.

[0074] The bottom sediment is collected by a columnar bottom sediment sampler, mixed uniformly, and placed in a cylindrical organic glass column with an inner diameter of 15 cm and a height of 40 cm. The height of the bottom sediment is uniformly 10 cm, and pure water is injected to make the water depth 20 cm. After being stabilized for 2 days, the experiment is started. During the experiment, the material is uniformly scattered on the surface of the sediment, covered with plastic wrap, and a certain number of small holes are uniformly punched on the plastic wrap to avoid excessive evaporation loss of water.

[0075] Experimental group Dosage material Material thickness Dosage amount 1-1 None - - 1-2 None - - 2-1 Sediment lock - Formula 1 0.15 cm 31.8g 2-2 Sediment lock - Formula 1 0.15 cm 31.8g 3-1 Sediment lock - Formula 2 0.15 cm 31.8g 3-2 Sediment lock - Formula 2 0.15 cm 31.8g 4-1 Sediment lock - Formula 3 0.15 cm 31.8g 4-2 Sediment lock - Formula 3 0.15 cm 31.8g

[0076] After 1 month of experiment, the physicochemical properties of the overlying water are detected, and the total nitrogen (TN) and total phosphorus (TP) concentrations in the overlying water are tested. The experimental results are shown in the following table.

[0077] Dosage material Total nitrogen (mg / L) Total phosphorus (mg / L) Blank 1.71±0.22 0.214±0.041 Formula 1 0.34±0.06 0.061±0.017 Formula 2 0.92±0.12 0.104±0.021 Formula 3 0.58±0.21 0.043±0.015

[0078] From the experimental results, it can be seen that formulations 1, 2, and 3 can effectively control the release of ammonia nitrogen and total phosphorus in the bottom sediment to the overlying water body.

[0079] The above examples are only for illustrating the technical concept and characteristics of the present application, and the purpose is to enable those skilled in the art to understand the content of the present application and implement it, and cannot limit the protection scope of the present application. Any equivalent changes or modifications made according to the spirit and essence of the present application should be covered within the protection scope of the present application.

Claims

1. A preparation method of a sediment locking agent for river and lake internal source pollution treatment, characterized in that: The method comprises the following steps: ​ S1: grinding the straw into powder for standby; S2: carbonizing part of the straw powder, and preparing straw biochar by acidizing; S3: weighing a certain amount of ferrous chloride and ferric chloride, adding them into deionized water, and stirring to form a first mixture; S4: adding the ground straw and straw biochar into the first mixture in S3, and stirring to form a second mixture; S5: adjusting the pH of the second mixture in S4 to 10 with an alkaline solution, and stirring to obtain modified magnetite containing straw and straw biochar; S6: freeze-drying the second mixture treated in S5, and then grinding into powder; S7: mixing the powder obtained in S6 with air-dried sediment, and grinding to prepare a sediment locking agent.

2. The method for preparing the sediment locking agent for in-situ pollution control of rivers and lakes according to claim 1, characterized in that: In S3, the mass ratio of ferrous chloride to ferric chloride is 1:

3.

3. The method for preparing the sediment locking agent for in-situ pollution control of rivers and lakes according to claim 2, characterized in that: In S3, the water bath kettle is stirred at a temperature of 80℃.

4. The method for preparing the sediment locking agent for in-situ pollution control of rivers and lakes according to claim 2, characterized in that: In S4, the stirring is performed for at least 30 minutes.

5. The method for preparing the sediment locking agent for in-situ pollution control of rivers and lakes according to claim 2, characterized in that: In S5, the stirring is performed for at least 1 hour.

6. The method for preparing the sediment locking agent for in-situ pollution treatment of rivers and lakes according to any one of claims 1-5, characterized in that: In S7, the ball milling is performed using a ball mill at a speed of 180 revolutions per minute, and the ball milling is performed for at least 1 hour.

7. A sediment locking agent for river and lake internal source pollution treatment, which is prepared by the method for river and lake internal source pollution treatment according to any one of claims 1-6, characterized in that: The method comprises straw powder, straw biochar, ferrous chloride, ferric chloride, and sediment.

8. A treatment method for treating in-lake internal pollution, characterized in that: The method comprises the following steps: S1: sampling the sediment in the pollution area to be treated; S2: analyzing the structure of the sediment, analyzing the physicochemical properties of the sediment, and determining the sediment environment; S3: determining the amount of the sediment locking agent according to claim 7; S4: adding the sediment locking agent into the pollution area to be treated; S5: regularly detecting the sediment in the pollution area to be treated; S6: adjusting the subsequent addition amount of the sediment locking agent.

9. The treatment method according to claim 8, characterized in that: In S2, the analyzed sediment can be divided into a sediment environment with low organic carbon content, a sediment environment with high pollutant concentration, and a sediment environment with poor microorganism species and quantity; in S3, the sediment locking agent with a corresponding formula is added according to the sediment environment, and the formula of the sediment locking agent includes a formula mainly containing straw for the sediment environment with low organic carbon content, a formula mainly containing magnetite and biochar for the sediment environment with high pollutant concentration, and a formula mainly containing sediment for the sediment environment with poor microorganism species and quantity.

10. The treatment method according to claim 9, characterized in that: The method further comprises the following steps: S7: after the treatment of the pollution area is completed or during the treatment, the sediment locking agent shell adsorbing the pollutants can be separated from the sediment by magnetic attraction.

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