Method for treating heavily contaminated farmland with salt-alkaline and heavy metal complexes in arid, contaminated irrigation areas.
Patent Information
- Application Number
- JP2025113260
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2025-02-26
- Filing Date
- 2025-07-03
- Publication Date
- 2026-09-07
- Estimated Expiration
- 2045-07-03
Smart Images
Figure 2026142496000001_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of soil remediation, specifically to saline-alkali heavy metal combined polluted agricultural land in arid polluted irrigation areas. Background Art
[0002] Arid polluted irrigation area refers to an arid sewage irrigation area, which is located in an arid or semi-arid climate zone, in a region with low annual precipitation and a prominent contradiction between supply and demand of agricultural water resources, where urban domestic sewage, industrial waste water or mixed sewage is used as the main irrigation water source for long-term agricultural production irrigation, . In recent years, in-situ remediation strategies for heavy metal polluted agricultural land mainly include the following types: adding soil conditioners to enhance the adsorption and fixation of heavy metals to soil particles, using hyperaccumulators to remove excess heavy metals from the soil, and planting low-accumulation crops to reduce the heavy metal content in the edible parts of crops. Deep ploughing is a common remediation technique for agricultural soil pollution. Studies have shown that after deep ploughing treatment of severely heavy metal combined polluted agricultural land soil, the pollutant content still continues to exceed the standard value. This is because deep ploughing treatment only mixes surface soil with high pollutant content and subsurface soil with relatively low pollutant content, and there is a limit to the effect of reducing the pollutant content of surface soil in severely heavy metal combined polluted soil. When the ex-situ remediation method is adopted, the transportation and treatment costs will increase significantly. Therefore, at present, there is a lack of soil treatment methods that are low-cost and have remarkable pollution treatment effects. Summary of the Invention
[0003] A method for treating saline-alkaline severely heavy metal combined polluted agricultural land in arid polluted irrigation areas includes the following steps: S1. Based on the degree of contamination of the contaminated farmland, select the fields to be treated from the contaminated farmland. S2. Next, the fields to be processed are grouped together, and fields within the same gradient range are classified into groups. The group obtains fields and paddies, and each of the fields in the group consists of one elevated field and one lower field. Including fields, the aforementioned same gradient range means that the difference in gradient between fields is 0-10%, and the higher terraces within each group of fields. The difference in elevation between cultivated fields and lower terraced fields is 1.0 to 3.0 m. S3. Next, the depth of the contaminated soil in the elevated fields and the lower fields is determined, and the depth of the contaminated soil Based on the depth, the contaminated soil of the fields to be treated is removed, and the contaminated soil after removal, Obtain high-terraced fields and low-terraced fields after separation, The step of determining the depth of contaminated soil in the aforementioned high-terraced fields and the aforementioned low-terraced fields is to determine the depth of soil at multiple depths. Samples are taken and detected to determine the cadmium, lead, arsenic, and copper content in soil at multiple depths. The measurement is performed, and the multiple depths are the first depth, second depth, ... and nth depth from the surface downwards. The distance between two adjacent depths is 20 cm, and the cadmium in the soil at the aforementioned depth n is If the average content of fluorine, lead, arsenic, and copper is below the selected value or regulatory value, then the nth The depth value was adopted as the depth of the contaminated soil. S4. Direct fertilization and tilling are carried out on the elevated fields after the stripping, and then crops are planted and treated. Complete, After the aforementioned delamination, trenches were dug in the lower terraced fields, soil was excavated from the trenches, and the layered backfilling method was used to create S3. The contaminated soil after delamination is backfilled into the trench and compacted, and then the soil excavated from the trench is used to fill the trench. and cover the lower terraced fields after the peeling to obtain the treated lower terraced fields. The aforementioned layered backfilling method involves dividing the contaminated soil after delamination into layers of 10 cm each, and after delamination The trench is backfilled layer by layer until the distance between the contaminated soil and the top of the trench is 40 to 60 cm. After compaction, the soil excavated from the trench is layered every 10 cm, and the top of the trench is raised to the same height as the top of the trench. The trench is then filled back in until the soil level is reached, and the soil excavated from the remaining trench is leveled on the lower terraced fields after the soil has been removed. Spray it once, S5, at 0.2m, 0.5m, and 2.0m from the outside of the furrow of the lower-level fields after the above treatment, respectively Soil sampling points were established at 0.5m and 3.0m from the outer edge of the lower terraced fields after the aforementioned treatment. And a groundwater sampling well is set up at 30m, and the soil sampling well The soil in the field and the groundwater in the groundwater sampling well are sampled periodically. The soil in the soil sampling point or the groundwater sampling well is monitored and monitored. If the concentration of contaminants in the groundwater inside increases over time, containment measures will be taken. A sample is taken from the soil sampling point, and the soil or groundwater sampling water at the soil sampling point is collected. If the concentration of pollutants in the groundwater within the area does not increase over time, then the low After demonstrating that no contamination spread from the contaminated soil in the trenches of the terraced fields occurred, we proceeded to the next step. S6. Fertilize and cultivate the lower-level fields where contamination does not spread, and then plant crops. The treatment of salt-alkaline heavy metals in arid, polluted irrigated areas is characterized by completing the treatment process. Methods for treating contaminated farmland. By using backfilling and consolidation methods for each layer, contaminated soil is buried intensively, preventing the diffusion of heavy metal contaminants. Reduce the scum, Furthermore, in S1, based on the degree of contamination of the contaminated farmland, The step of selecting fields to be treated from contaminated farmland involves examining the soil contamination status of the contaminated farmland, and soil Treating farmlands where the contents of cadmium, lead, arsenic and copper exceed the selected values or regulatory values as the farmlands to be treated. Description: The above selected values or regulatory values refer to "Soil Environmental Quality Risk Management and Control Standard for Soil Pollution of Agricultural Land (Trial)" (GB15618-2018). Herein, the allowable range for safe utilization of cadmium shall not exceed the regulatory value specified in the standard, and the allowable range for safe utilization of lead, arsenic and copper shall not exceed the selected value specified in the standard. shall not exceed the selected value specified in the standard. Setting to maintain the relative elevation between the high-level farmland and the low-level farmland can avoid changing the local terrain and water flow direction. Furthermore, in step S3, in step S3, the stripping method comprises: for each set of farmlands in the plurality of sets of farmlands, layering the high-level farmland and the low-level farmland at an interval of 10 cm, stripping the contaminated soil layer by layer from the surface soil to the depth of the contaminated soil, and stacking the stripped contaminated soil on the stripped low-level farmland . Description: Confirming the depth layer by layer through the above method can identify the safe utilization depth, the selected values or regulatory values refer to "Soil Environmental Quality Risk Management and Control Standard for Soil Pollution of Agricultural Land ( Trial)" (GB15618-2018). Herein, the allowable range for safe utilization of cadmium shall not exceed the regulatory value specified in the standard, and the allowable range for safe utilization of lead, arsenic and copper shall not exceed the selected value specified in the standard. Furthermore, in step S4, in step S4, the distance between the position of the ditch and the edge of the stripped low-level farmland is greater than 2.0 m, and the relationship among the depth of the ditch, the excavation area of the ditch, the depth of the contaminated soil and the area of the farmland to be treated is shown in the following formula: JPEG2026142496000002.jpg3061+ In formula 1517, JPEG2026142496000004.jpg1223 is the depth of the trench, JPEG2026142496000005.jpg1516 is the excavation area of the trench, JPEG2026142496000006.jpg128 is the depth of the contaminated soil, JPEG2026142496000007.jpg1417 is the area of the farmland to be treated, JPEG2026142496000008.jpg1510 is the volume conversion coefficient for earth and stone, JPEG2026142496000009.jpg1512 is the preliminary opening coefficient of the trench. Description: According to the above formula, appropriate trench dimensions are calculated based on the amount of contaminated soil, so as to maintain the levelness of the farmland after stripping. At the same time, this design ensures proper embedding of contaminated soil and reduces the risk of diffusion of contaminants in the soil. the diffusion risk of contaminants in the soil. Furthermore, the plowing depth is 18 to 25 cm, and the crop is corn. Description: The above thickness and plowing depth have high practical applicability. Compared with crops such as wheat, soybean and sesame, which are the main local crops, Compared with crops such as these, corn has an excellent low cadmium accumulation effect, and can reduce cadmium accumulation in seeds. Furthermore, in step S5, the anti-diffusion measures are as follows: excavating an isolation trench 0.5 to 2 m from the outer edge of the trench, with a width of 0.2 to 0.4 m and a depth equal to that of the original trench, 0.5~2m, with a width of 0.2~0.4m and a depth the same as that of the trench, and filling the isolation trench with anti-contamination diffusion filler, wherein the anti-contamination diffusion filler comprises 100 parts by weight of quicklime and 100 parts by weight of attapulgite. Description: The arrangement of the isolation trench prevents the diffusion and migration of heavy metals in the contaminated soil. By adjusting the raw materials and mixing ratio of the filler, By adjusting the raw materials and mixing ratio, the precipitation and adsorption performance of the composite filler are improved, and the heavy It fixes and stabilizes metal ions, reducing their movement and diffusion in the environment. Furthermore, including the installation of multiple civil engineering standard rooms at the edges of the lower-level fields after processing in S4. Then, high-altitude fescue plants were planted in each civil engineering standard room, and afterwards the civil engineering standard rooms were covered with nonwoven fabric. The standard room for civil engineering works is made of a plastic grid structure and is regularly watered and maintained. This further includes a certain step. Description: The standard chamber for civil engineering works effectively stabilizes soil and prevents soil erosion caused by rainwater. It is possible. The root system of highland fescue plants further strengthens soil stability and reduces erosion. It is possible. The Civil Engineering Standard Room increases the shear strength of the soil through its grid structure, and the lateral slope The overall stability of the surface can be improved. By covering it with nonwoven fabric, wind erosion can be reduced. It reduces the impact on slope soil while simultaneously providing heat retention and moisture retention to the soil, preventing excessive evaporation. This can prevent problems and promote the growth and sprouting of plant roots. The present invention involves removing and backfilling heavily contaminated cultivated soil, and then backfilling the area with soil and groundwater. Boundary monitoring points will be established, and improvement measures such as soil fertilization will be implemented for the newly formed surface soil. This restores soil productivity, improves soil quality, and reduces cadmium accumulation in corn products. By planting seeds, it is possible to safely re-cultivate farmland heavily contaminated with heavy metals. Through multi-technology collaborative processing, the ecology of severe heavy metal complex contamination in saline-alkaline farmland in contaminated irrigation areas. This can significantly reduce academic risks and ensure the sustainable use of contaminated farmland. [Brief explanation of the drawing]
[0004] [Figure 1] This is a diagram showing the total Cd distribution data of contaminated soil in Example 2 of the present invention. [Figure 2]This figure shows the change in Cd content before and after the removal of contaminated soil in Example 2 of the present invention. [Figure 3] This is a diagram showing the total Pb distribution data for soil in Example 2 of the present invention. [Figure 4] This figure shows the change in Pb content before and after soil removal in Example 2 of the present invention. [Figure 5] This figure shows the total soil As distribution and changes before and after delamination in Example 2 of the present invention. [Figure 6] This figure shows the data on the change in As content before and after soil removal in Example 2 of the present invention. [Figure 7] This figure shows the total Cu distribution in the soil and the changes before and after delamination in Example 2 of the present invention. [Figure 8] This figure shows the data on the change in Cu content before and after the removal of contaminated soil in Example 2 of the present invention. [Figure 9] This figure shows the Cd content of corn seeds after normal deep plowing and soil removal in Example 2 of the present invention. [Modes for carrying out the invention]
[0005] As can be seen from the background technology described above, arid polluted irrigation areas are located in arid or semi-arid climate zones. In areas with low annual rainfall and a significant imbalance between agricultural water supply and demand, urban wastewater, Areas where industrial wastewater or mixed wastewater is used as the primary irrigation water source for long-term agricultural production irrigation. This refers to the heavy metals such as cadmium that penetrate alkaline soil, mainly in the cultivated layer (0-20°C). m) Adsorbed and precipitated by the soil, remains in the soil layer for a long period of time, and is located in the deep (>20cm) soil Therefore, the content is relatively low. Salt in soil is important for the mobility and biological availability of heavy metals. This increases the risk of heavy metal contamination in saline soils, significantly altering the environmental and health risks associated with such contamination. According to research, complex interactions exist between heavy metals such as Cd and basic ions, for example. Na in the soil+ Basic ions such as these are adsorbed onto the soil surface by displacement, and heavy metal ions are also adsorbed. This replaces the heavy metals in soil, improving their mobility and bioavailability. Therefore, due to the complexity of the salt-alkaline, severely heavy-metal complex contaminated soil, remediation treatment is difficult. In the actual restoration process, various methods such as soil improvement, plant restoration, and chemical restoration are combined. This needs to be taken into consideration. To reduce the level of heavy metal complex contamination in saline soils while simultaneously ensuring safe crop production. Therefore, embodiments of the present invention provide the following executable methods: Example 1: Method for treating heavily contaminated farmland with salt-alkaline and heavy metal complexes in arid, contaminated irrigation areas. The law includes the following steps: S1. Based on the degree of contamination of the contaminated farmland, select the fields and paddies that should be treated from the contaminated farmland, and specifically The soil contamination status of the contaminated farmland was investigated, and any of the following substances in the soil were detected: cadmium, lead, arsenic, and copper. Fields with content exceeding the selected value or regulatory value are designated as fields that should be treated. S2. After that, the fields to be processed are grouped together, and fields within the same gradient range are classified into groups, and the same gradient The term "range" means that the difference in gradient between fields is 0-10% (for example, 5%), and multiple sets of fields... Having acquired fields, each of the multiple sets of fields includes one elevated field and one lower field. The difference in elevation between the higher and lower terraced fields in each of the multiple sets of fields is 2.0m. S3. Subsequently, the depth of contaminated soil in the high-terraced and low-terraced fields was determined, and based on the depth of the contaminated soil... Next, the contaminated soil of the fields to be treated was removed, and the contaminated soil after removal, and the elevated fields after removal After peeling, low-level terraced fields are obtained. The step of determining the depth of contaminated soil in high-terraced and low-terraced fields is: Soil samples were taken from multiple depths for detection, and cadmium, lead, and arsenic were detected in the soil at multiple depths. The copper content was obtained, and the multiple depths were the first depth, second depth, ... and nth depth from the surface downwards. The depth includes the distance between two adjacent depths, and the cadmium in the soil at the nth depth is 20 cm. If the average content of um, lead, arsenic, and copper is below the selected value or regulatory value, then the nth depth The degree value is defined as the depth of the contaminated soil. The separation method is as follows: For each group of fields in a group of fields, high-terraced fields and low-terraced fields The soil is divided into layers every 10 cm, and the contaminated soil is separated layer by layer from the surface soil down to the depth of the contaminated soil. The contaminated soil after decontamination is piled up on the lower terraced fields after decontamination. S4. Direct fertilization and tilling are carried out on the terraced fields after the delamination process, followed by planting of crops and completion of the treatment. Okay, After the soil has been removed, trenches are dug in the lower terraced fields, soil is excavated from the trenches, and each layer is backfilled using the S method. The contaminated soil that was separated in step 3 was backfilled into the trench and compacted, and then the soil that was excavated from the trench was used Cover the trenches and the lower terraced fields after peeling to form the treated lower terraced fields. The distance between the location of the ditch and the edge of the low-level rice paddy after separation was 3.0m, and the depth of the ditch and the area of the ditch excavation were also measured. The relationship between the depth of the contaminated soil and the area of fields to be treated is shown by the following formula: JPEG2026142496000010.jpg3061+ In the JPEG2026142496000011.jpg1517 format, JPEG2026142496000012.jpg1223 This is the groove depth, JPEG2026142496000013.jpg1516 represents the excavation area of the trench. JPEG2026142496000014.jpg128 shows the depth of the contaminated soil. JPEG2026142496000015.jpg1417 represents the area of fields and farmland to be processed. JPEG2026142496000016.jpg1610 is a volume conversion factor for soil and stone. JPEG2026142496000017.jpg1612 is the groove opening preliminary coefficient. JPEG2026142496000018.jpg1610 represents the ratio of the actual soil volume after consolidation to the original soil volume, and reflects the compressive properties of the soil during the consolidation process. Reflecting the compaction effect, JPEG2026142496000019.jpg1610 depends on factors such as soil type and soil moisture content (value range 0.67~1.0), and according to the present invention In the embodiment, The value for JPEG2026142496000020.jpg1610 is 0.87. JPEG2026142496000021.jpg1612 is related to the distribution of plant root systems, and its value must be greater than or equal to the plant root system distribution depth, for example, If plant root systems are distributed within 0.2m of soil, in order to avoid plant root system growth in contaminated soil... , 0.4m was adopted, Here, the area of the groove JPEG2026142496000022.jpg1516 is The image satisfies the conditions of JPEG2026142496000023.jpg1660, where a is the length of the field L-4 m and b is the width of the field M-4 m. The layered backfilling method is as follows: After delamination, the contaminated soil is divided into layers of 10 cm each, and after delamination... The soil was backfilled layer by layer into the trench and compacted until the distance between the contaminated soil and the top of the trench was 40 cm. After excavating from the trench, the soil was divided into 10cm layers and the trench was dug until it was level with the top of the trench. The soil was backfilled, and the soil excavated from the remaining trenches was evenly spread over the lower terraced fields after the soil had been removed. Excavate an isolation trench 0.5 m from the outer edge of the trench, with a width of 0.2 m and a depth equal to the depth of the trench, and isolate The trench is filled with a contamination prevention filler, and the contamination prevention filler is equivalent to 100 parts by weight of quicklime. Including 100 copies of the Atapalgait, Here, the thickness of the soil excavated from the trench after backfilling was 40 cm, and the tillage depth was 20 It is cm, and the crop is corn. S5. Soil samples were taken at 0.2m, 0.5m, and 2.0m from the outside of the furrows in the lower terraced fields after treatment. Set sampling points and measure 0.5m, 3.0m, and 3m from the outer edge of the lower terraced fields after processing. Groundwater sampling wells were set at 0m, and soil was collected at the soil sampling points. In addition, groundwater in the groundwater sampling well is periodically sampled and monitored, and soil samples are taken. Contaminant concentration in soil or groundwater sampling wells at sampling points If the levels are observed to rise over time, containment measures should be taken and soil samples taken. The concentration of contaminants in the soil or groundwater sampling well at the sampling point is measured over time. If we monitor that the levels do not rise over time, the diffusion of contaminants in the contaminated soil within the ditches of the lower-level fields will be It indicates that this does not occur, and proceeds to the next step. Containment measures include managing irrigation volume and preventing the infiltration of contaminants with water through excessive irrigation. Alternatively, the method of strengthening the barrier, which may include replacing the filler in the isolation trench, or includes widening the isolation groove, S6, Multiple standard civil engineering chambers (40cm x 40cm x 15cm) at the edges of the low-level fields after processing. ) were installed, and plants such as highland fescue were planted in each civil engineering standard room, and then the civil engineering standard room Cover it with nonwoven fabric and water and maintain it regularly. Here, the civil engineering standard room is plastic It is a grid-like structure made of [material name]. S7. Fertilize and cultivate the low-lying fields where contamination spread does not occur, then plant crops and treat Complete the process. Example 2: Exemplarily, a heavily contaminated, salt-alkaline, heavy-metal composite farmland in a dry, contaminated irrigated area The processing method includes the following S1-S7: S1. Based on the degree of contamination of the contaminated farmland, select fields to be treated from the contaminated farmland and apply contaminated irrigation. Select farmland in the region with severe heavy metal complex contamination of salt-alkaline soil, and clearly distinguish between the selected fields. There is a difference in elevation, specifically, the remediation of soil contaminated with a complex mixture of salt, alkali, and heavy metals in a certain area of a certain city. A physical test was conducted to investigate the soil environmental quality of a certain area in a certain city, and according to the results, the area The total salinity of the agricultural soil reached 3.29 ± 0.21 g / kg, and the top 0-20 cm of the area was affected. The total Cd, Pb, As, and Cu content in the soil is 71.2 ± 32.6 mg / kg, 826±768 mg / kg, 43.9±26.2 mg / kg, and 263±159 These values are mg / kg and all conform to the "Soil Environmental Quality Agricultural Land Soil Contamination Risk Management and Control Standards" (GB). If the selected value or regulatory value specified in 15618-2018 exceeds the specified value, S2. After that, the fields to be processed are grouped together, and fields within the same gradient range are classified into groups, and multiple groups are formed. The land is divided into several groups, each of which includes one high-level field and one low-level field. Furthermore, the difference in elevation between the higher and lower terraced fields in each of the multiple sets of fields reaches 2.0m or more. Specifically, the two types of fields, high-terraced and low-terraced, are used for crops such as corn, wheat, or soybeans. It was planted with [plant name], covering a total area of approximately 900m². 2 The terraced rice fields are approximately 500m 2 So, low-level rice paddy fields The volume is approximately 400 m 2 Both fields are contaminated with a complex mixture of alkaline salt and heavy metals. The distribution of total soil Cd, Pb, As, and Cu is shown in Figures 1, 3, 5, and 7. The exam period is from September 2021 to October 2021. S3. Subsequently, the depth of contaminated soil in the high-terraced and low-terraced fields was determined, and based on the depth of the contaminated soil... Next, the contaminated soil of the fields to be treated was removed, and the contaminated soil after removal, and the elevated fields after removal After removing the soil, we obtained low-level terraced fields, and specifically in September 2021, we used a grid arrangement method for soil drilling. Soil samples were collected at 0-20cm, 20-40cm, and 40-60cm before peeling, and Then, using a large loader, the contaminated soil from 0 to 40 cm in the high and low terraced fields was separated layer by layer, The detached soil thickness was 10 cm, and a total of four detachment procedures were performed. S4. In the lower terraced fields after separation, use an excavator to dig a trench 2.0m from the edge of the lower terraced fields. The soil excavated from the trench and the contaminated soil after the surface layer has been removed were piled up separately, and then after the removal... The contaminated soil was backfilled into the trench, compacted layer by layer, and the soil was excavated from the trench at a depth of 40 cm from the opening. The soil is backfilled layer by layer, compacted layer by layer, and backfilling is stopped when it reaches the same height as the trench opening, and the remaining The soil excavated from the trenches is spread uniformly on the surface of the lower-level fields, and a level is used during the backfilling and leveling processes. Using a land leveling machine, we ensure the terrain is flat. S5. Soil samples were taken at 0.2m, 0.5m, and 2.0m from the outside of the furrows in the lower terraced fields after treatment. Set sampling points and measure 0.5m, 3.0m, and 3m from the outer edge of the lower terraced fields after processing. Groundwater sampling wells were set at 0m, and soil was collected at the soil sampling points. In addition, groundwater in the groundwater sampling well is periodically sampled and monitored, and soil samples are taken. Contaminant concentration in soil or groundwater sampling wells at sampling points If the levels are observed to rise over time, containment measures should be taken and soil samples taken. The concentration of contaminants in the soil or groundwater sampling well at the sampling point is measured over time. If we monitor that the levels do not rise over time, the diffusion of contaminants in the contaminated soil within the ditches of the lower-level fields will be It indicates that this does not occur, and proceeds to the next step. For example, soil and groundwater samples are taken at soil sampling points every two months. The groundwater in the well is sampled and monitored, and in addition, large-scale monitoring is conducted in the fields every two months. Relevant samples were collected from the particle sedimentation collection device and the outlet of the irrigation channel, and contaminated soil was buried. After the fields were returned to their original state, a soil-side infiltration water collection device was installed on the outside of the ridges, and during irrigation and surface runoff... Even in large cases, no water samples infiltrating from within the fields were observed. Changes in the total Cd, Pb, As, and Cu content of the surface soil (0-20 cm) before and after detachment. The situation is shown in Figures 2, 4, 6, and 8, and compared to before peeling, the total amount of Cd, Pb, and A The content of s and Cu is 95.6%, 84.7%, 51.2%, and 71.1%, respectively. The results show that the amount of salt-alkaline heavy metal complex contamination in agricultural areas within the study region decreased. After stripping the soil, the level of heavy metal contamination in the newly generated surface soil was significantly lower. The newly formed cultivated layer meets the conditions for safe use research, and furthermore, after peeling... The resulting cultivated soil is maintained in accordance with field management standards, including measures such as weed removal and winter irrigation. It is managed, optimizes soil environmental conditions, and supports crop cultivation work for the following year. S6, Multiple standard civil engineering chambers (40cm x 40cm x 15cm) at the edges of the low-level fields after processing. ) will be set up, and plants such as highland fescue will be planted in each civil engineering standard room, and then the civil engineering standard room Cover it with nonwoven fabric and water and maintain it regularly. Here, the civil engineering standard room is plastic It is a grid-like structure made of [material name], and it should be noted that the Civil Engineering Standard Room is a standard commercially available product. The domestic and international standards are as follows: China: GB / T 19274-2017 "Standard Room for Composite Materials and Plastics in Civil Engineering Works" Bikuni: ASTM D7864 (Standard Test Method) The specific dimensions and mechanical parameters of the standard chamber for civil engineering works are to be selected by those skilled in the art as needed. As long as it is (a standard HDPE construction room of a certain brand), the present invention is not particularly limited, S7. Fertilize and till the fields where contamination spread does not occur, then plant crops and carry out the treatment. Completed, Specifically, organic matter derived from agricultural and forestry waste is rich in organic matter and contributes to soil improvement, cultivation, and development. It is helpful in the process of removing soil from the cultivated layer soil, and can promote crop growth. To reduce heavy metal concentrations, the original cultivated soil layer was removed and backfilled, and newly generated soil was created. Because the cultivated soil is relatively poor, applying a large amount of organic matter effectively improves soil quality. This can be improved to enhance the growing environment for crops. After the start of the cultivation season, organic matter is spread on the fields (winter irrigated) after the soil has been removed, and after tilling, the organic matter and new Thoroughly mix the cultivated soil layer to construct and cultivate good new soil, and the cultivated soil layer after reconstruction It improves fertility and productivity, and the organic matter N:P:K content is 5.45±0.26g / The values were 1.97±0.07 g / kg, 18.75±0.92 g / kg, and organic matter. The content is 75.5 ± 2.3 g / kg, and the organic matter application rate is 6 T / furrow, applied continuously for 3 years. This is the plan, Preferably, a maize variety with high drought tolerance, high yield, high lodging resistance, and low cadmium absorption. Select "Kinzono 007" and apply base fertilizer (compound fertilizer: N-P2O5-K2O15-15-15) before cultivation. ) was applied at a rate of 40 kg / ridge, when the corn had 10-12 leaves, phosphorus Apply a top dressing of a mixture of diammonium hydrogen oxyhydrogen (2 parts) and urea (1 part), using the method of application by filling holes and covering with soil. Then, the amount of fertilizer to apply after mixing is 30 kg / furrow, and it should be applied before 10 AM or after 4 PM on a windless or rainless day. 55% nitrosulfazole atrocin herbicide applied at a 150x dilution when corn has 3-5 leaves. Dilute and spray, applying 200g / ridge, and after winter irrigation of the previous year, tillage and tilling of the soil They meet the water needs of corn seedlings by retaining moisture, and then each seedling grows to 10-12 leaves. After top dressing, irrigation should be carried out during the internode elongation / ear formation stage, heading / flowering stage, and maturation stage to promote corn growth. After maturation, the mustard and seeds are harvested, washed, dried, and crushed, then digested, and the cadmium in the digestate is analyzed. The concentration was measured by ICP-MS, and the data obtained from the test process was saved in Excel 2013. The data was analyzed using SPSS 16.0 software, and the differences between data processed using analysis of variance (L). Multiple comparisons were evaluated using SD, and among corn seeds planted after normal deep plowing and soil deburring... The change in Cd content is shown in Figure 9, and after the land delamination treatment, the cadmium in the newly generated cultivated layer The cadmium content decreased significantly, and as a result, the cadmium content in corn seeds also decreased. did. Example 3: It differs from Example 2 in the following respects: High-terraced and low-terraced fields in each of the multiple sets of fields The difference in elevation between them is 1.0 m, and an isolation trench with a width of 0.2 m was excavated at 0.5 m from the edge of the trench, separating them. Fill the trench with filler until the distance between the detached soil and the upper edge of the trench at S4 is 40 cm. The trenches were backfilled layer by layer and compacted, and in S4, the soil thickness excavated from the trenches reached 40 cm. The soil was covered until it was fully grown, the tillage depth was 18 cm, and the crop was corn. Example 4: It differs from Example 2 in the following respects: High-terraced and low-terraced fields in each of the multiple sets of fields The difference in elevation between them is 3.0m, and a 0.4m wide isolation trench was excavated 2m from the edge of the trench. Fill the trench with filler, and in S4, fill the trench until the distance between the detached soil and the edge of the trench top is 60 cm. Each layer was backfilled and compacted, and in S4, the thickness of the soil excavated from the trench reached 60 cm. The soil was covered until it was tilled to a depth of 25 cm, and the crop was corn.
Claims
1. A method for treating heavily contaminated farmland with salt-alkaline and heavy metal complexes in arid, polluted irrigation areas. 、 S1. Based on the degree of contamination of the contaminated farmland, select the fields to be treated from the contaminated farmland. Top and, S2. Next, the fields to be processed are grouped together, and fields within the same gradient range are classified into groups. The group of fields is obtained, and each of the fields in the group consists of one elevated field and one lower field. Including fields, the aforementioned same gradient range means that the difference in gradient between fields is 0-10%, and the higher terraces within each group of fields. The difference in elevation between the fields and the lower terraced fields is 1.0 to 3.0 m, and S3. Next, the depth of the contaminated soil in the elevated fields and the lower fields is determined, and the contaminated soil Based on the depth, the contaminated soil of the fields to be treated is removed, and the contaminated soil after removal, Obtain high-terraced fields and low-terraced fields after separation, The step of determining the depth of contaminated soil in the aforementioned high-terraced fields and the aforementioned low-terraced fields is to determine the depth of soil at multiple depths. Samples are taken and detected to determine the cadmium, lead, arsenic, and copper content in soil at multiple depths. The measurement is performed, and the multiple depths are the first depth, second depth, ... and nth depth from the surface downwards. The distance between two adjacent depths is 20 cm, and the cadmium in the soil at the aforementioned depth n If the average content of fluorine, lead, arsenic, and copper is all below the selected value or regulatory value, then the nth The steps include adopting the depth value as the depth of the contaminated soil, S4. Direct fertilization and tilling are carried out on the elevated fields after the detachment, followed by planting crops and treatment. Complete, After the aforementioned delamination, trenches were dug in the lower terraced fields, soil was excavated from the trenches, and the layered backfilling method was used to create S3. The contaminated soil after delamination is backfilled into the trench and compacted, and then the soil excavated from the trench is used to fill the trench. and cover the lower terraced fields after the peeling to obtain the treated lower terraced fields. The aforementioned layered backfilling method involves dividing the contaminated soil after delamination into layers of 10 cm each, and after delamination The trench is backfilled layer by layer until the distance between the contaminated soil and the top of the trench is 40 to 60 cm. After compaction, the soil excavated from the trench is layered every 10 cm, and the top of the trench is raised to the same height. The trench is then filled back in until the soil level is reached, and the soil excavated from the remaining trench is leveled on the lower terraced fields after the soil has been removed. The first step is to spray, S5, at 0.2m, 0.5m, and 2.0m from the outside of the furrow of the lower-level fields after the above treatment, respectively Soil sampling points were established at 0.5m and 3.0m from the outer edge of the low-level terraced fields after the aforementioned treatment. And a groundwater sampling well is set up at 30m, and the soil sampling well The soil in the field and the groundwater in the groundwater sampling well are sampled periodically. The soil in the soil sampling point or the groundwater sampling well is monitored and monitored. If the concentration of contaminants in the groundwater inside increases over time, containment measures will be taken. A sample is taken from the soil sampling point, and the soil or groundwater sampling water at the soil sampling point is collected. If the concentration of pollutants in the groundwater within the area does not increase over time, then the low This step demonstrates that no contamination will spread from the contaminated soil in the trenches of the terraced fields, and then proceeds to the next treatment step. and, S6. Fertilize and cultivate the lower-level fields where the aforementioned contamination spread does not occur, and then plant crops. , the steps to complete the process, Agricultural treatment of salt-alkaline severe heavy metal complex contamination in arid, polluted irrigated areas, characterized by including Methods for dealing with the ground.
2. In S1 above, based on the degree of contamination of the contaminated farmland, the fields to be treated from the contaminated farmland are selected. The selection step involves examining the soil contamination status of the contaminated farmland and checking for cadmium, lead, and arsenic in the soil. This includes designating fields where the copper content exceeds the selected or regulated value as fields that should be treated. The method according to feature 1.
3. In S3, the peeling method is performed on each of the multiple sets of fields, the high step The fields and the aforementioned lower-level fields were separated into layers every 10 cm, and the contaminated soil was separated from the surface soil to the depth of the contaminated soil. This involves peeling off each layer and piling the peeled contaminated soil onto the lower terraced fields. The method according to claim 1, characterized by the following.
4. In S4, the distance between the position of the groove and the edge of the low-level field after peeling is greater than 2.0 m. In general, the depth of the trench, the excavation area of the trench, and the depth of the contaminated soil, and the fields to be treated The relationship between the areas is shown by the following equation: + In the formula, This is the depth of the groove. This is the excavation area of the trench, This is the depth of the contaminated soil. This is the area of fields and farmland that need to be processed. This is the volume conversion coefficient for soil and rock, The method according to claim 1, characterized in that is a groove opening preliminary coefficient.
5. In S5, the diffusion prevention measures are as follows: from the outer edge of the groove, 0.5 to Excavate an isolation trench 2m wide, 0.2 to 0.4m deep, and the same depth as the trench, and contaminate the isolation trench. A diffusion-preventing filler is filled in, and the contamination diffusion-preventing filler is made up of 100 parts by weight of quicklime and The method according to claim 1, characterized by comprising 100 parts of attapulgate.
6. After processing in S4, multiple civil engineering standard rooms were installed at the edges of the lower-level fields, and each civil engineering standard room Highland fescue plants were planted, and then the civil engineering standard room was covered with nonwoven fabric and watered and piped regularly. The civil engineering standard room is a plastic grid structure, and the steps are further The method according to claim 1, characterized by including