Treatment process applied to soil heavy metal pollution

Abstract

The invention relates to the technical field of soil remediation, and particularly discloses a treatment process applied to soil heavy metal pollution. The treatment process applied to soil heavy metal pollution comprises the following steps that 1, poplar planting points are positioned on polluted soil and marked, and the marked areas are consistent with planting pits needed for planting in plane shape and size; (2) a water stop fence is inserted into the marked area to completely surround the marked area; step 3), irrigating a nutrient solution in the marked area, and standing for 7-8 days; 4, the water stop fence is detached, planting pits are dug, after poplar seedlings are planted, soil dug out of the planting pits is completely backfilled, and after the poplar seedlings grow, the soil is purified; the nutrient solution is prepared by compounding corynespora aspera, candida tropicalis, acetobacter xylinum, water and nutrients. The method has the advantages that the survival rate of the poplar saplings is increased, and the cost for repairing the mercury and cadmium polluted soil is reduced.

Description

Technical Field

[0001] The present invention relates to the field of soil remediation, and in particular to a treatment process for heavy metal pollution in soil. Background Art

[0002] The accumulation of heavy metals such as mercury, lead, cadmium, chromium, copper, etc. in the soil not only destroys the natural circulation capacity of the soil, but also threatens the safety of humans and other organisms through the food chain. Therefore, it is necessary to repair the soil contaminated by heavy metals.

[0003] When repairing soil contaminated by heavy metals, it is necessary to first determine the specific type of heavy metal pollutant. Different heavy metal pollutants require corresponding repair methods. Among them, soil contaminated by mercury and cadmium has a particularly serious impact on the food chain. Moreover, with the development of human chemical production, mercury and cadmium pollution has become more serious.

[0004] For soil contaminated by mercury and cadmium, the current main method is to apply lime to increase the pH of the soil environment so that mercury and cadmium can form precipitates that are not easily absorbed by plants. This treatment method can only reduce the impact of contaminated soil on the food chain, but cannot cure it completely. It is only a temporary solution and not a permanent cure. If you want to remove mercury and cadmium from the soil, you can plant plants that absorb mercury and cadmium. Currently, plants that can absorb total mercury and cadmium in the soil and have higher economic value in the future include poplar trees. Although mature poplar trees have higher economic value, it has been found in practice that planting poplar seedlings in soil highly contaminated by mercury and cadmium will lead to a significant drop in the survival rate of the poplar trees, resulting in large economic losses, making the initial investment too large and difficult to promote on a large scale. Therefore, there is still room for improvement. Summary of the invention

[0005] In order to improve the survival rate of poplar seedlings and reduce the cost of repairing mercury and cadmium contaminated soil, the present application provides a treatment process for heavy metal pollution in soil.

[0006] The present application provides a treatment process for heavy metal pollution in soil using the following technical solution: A treatment process for heavy metal pollution in soil, comprising the following steps: Step 1), locating and marking the poplar planting site on the contaminated soil, wherein the marked area is consistent with the plane shape and size of the planting pit required for planting; Step 2), insert a water-stop fence into the marked area to completely surround the marked area; Step 3), water the marked area with nutrient solution and wait for 7-8 days; Step 4), dismantle the water-stop enclosure, dig a planting pit, plant the poplar saplings, and then backfill all the soil dug out from the planting pit, waiting for the poplars to grow to purify the soil; The nutrient solution is a compound of Portuguese corynespora yeast, tropical candida, xylinum acetobacter, water and nutrients.

[0007] By adopting the above technical scheme, the nutrient solution prepared by mixing Portuguese coryneformis, tropical candida, xylinum acetobacter, water and nutrients is irrigated into the soil at the planting pit, so that Portuguese coryneformis, tropical candida and xylinum acetobacter multiply in the soil, and the fermentation products thereof can promote the rooting of poplars and thus improve the survival rate. After the poplars are planted, under the action of high concentrations of Portuguese coryneformis, tropical candida and xylinum in the soil of the planting pit area, the poplars can have a high survival rate even in the soil with serious mercury and cadmium pollution, thereby reducing the economic losses caused by the withering of poplar seedlings and effectively controlling the initial investment costs. When the poplars are mature, they can not only absorb mercury and cadmium in the soil to achieve the effect of soil restoration, but also cut down the poplars. Although the heavy metals in the poplars planted in this way will exceed the standard, after the wood is processed, not only the wood resources are utilized, but also the heavy metals can be recovered, which can generate considerable economic benefits, thereby reducing the cost of controlling soil heavy metal pollution to a certain extent, so that the control process applied to soil heavy metal pollution can be better promoted.

[0008] Preferably, in the nutrient solution, the mass ratio of Portuguese spore yeast, tropical Candida, xylinum Acetobacter, water, and nutrients is 0.012-0.014: 0.007-0.009: 0.015-0.017: 1000: 13.2-18.5.

[0009] By adopting the above technical scheme and specifically selecting the mass ratios of Portuguese Corynespora, tropical Candida, Acetobacter xylinum, water and nutrients, the nutrient solution can better improve the survival rate of poplars while effectively controlling costs, thereby having higher economic value.

[0010] Preferably, the nutrients in the nutrient solution are a combination of Physalis juice, Pyracantha fortuneana juice, Raspberry juice, glucose, peptone, potassium chloride, sodium chloride and vitamin C.

[0011] By adopting the above technical scheme, by specifically selecting nutrients as a combination of Physalis juice, Pyracantha fortuneana juice, Vitis vinifera juice, glucose, peptone, potassium chloride, sodium chloride, and vitamin C, Portuguese Coryneformis, Tropical Candida, and Xylinum Acetobacter can reproduce rapidly and increase the bacterial concentration rapidly, thereby rapidly increasing the concentration of Portuguese Coryneformis, Tropical Candida, and Xylinum Acetobacter in the soil at the planting pit, thereby achieving a better effect on improving the survival rate of poplar trees.

[0012] Preferably, in the nutrients, the mass ratio of Physalis juice, Pyracantha fortuneana juice, Vitis vinifera juice, glucose, peptone, potassium chloride, sodium chloride and vitamin C is 1-2: 2-3: 5-6: 2-3: 2-3: 0.5-0.6: 0.5-0.6: 0.2-0.3.

[0013] By adopting the above technical scheme and specifically selecting the mass ratios of Physalis juice, Pyracantha fortuneana juice, Vitis vinifera juice, glucose, peptone, potassium chloride, sodium chloride and vitamin C, the reproduction of Portuguese Corynespora can be accelerated better, the quality of the nutrient solution can be better, and the survival rate of poplars can be better improved.

[0014] Preferably, the preparation method of the nutrient solution is as follows: Mix water and nutrients evenly, then add Portuguese coryneformis, tropical Candida, and xylinum Acetobacter, and culture at a constant temperature of 35-37°C for 4-5 days to obtain a nutrient solution.

[0015] By adopting the above technical scheme, by culturing at 35-37°C for 4-5 days, the Portuguese spore yeast, tropical Candida, and xylinum acetobacter are highly active and can reproduce rapidly, so as to ensure that after the nutrient solution is irrigated into the soil, the Portuguese spore yeast, tropical Candida, and xylinum acetobacter can continue to reproduce rapidly in the soil, thereby achieving a better effect of improving the survival rate of poplar trees.

[0016] Preferably, in step 2), the insertion depth of the water stop enclosure is 1-1.5m.

[0017] By adopting the above technical solution and specifically selecting the insertion depth of the water-stop enclosure, the nutrient solution can be better controlled within the range of the planting pit, reducing the waste of nutrient solution, and better improving the soil in the planting pit, so that the survival rate of poplar seedlings is higher, while better controlling costs and having higher economic value.

[0018] Preferably, in step 3), when watering the nutrient solution, every 1m 2 Water the soil area with 400-500kg of nutrient solution.

[0019] By adopting the above technical solution, by specifically selecting every 1m 2 400-500kg of nutrient solution is poured into the soil area to ensure that the nutrient solution can penetrate into the soil to below the depth of the planting pit, so that the soil dug out from the planting pit is soil improved with nutrient solution, so that the roots of the poplar seedlings can be wrapped by soil rich in Portuguese Corysporum, tropical Candida, and Acetobacter xylinum, which has a better effect on improving the survival rate of the poplar seedlings.

[0020] Preferably, in step 4), the depth of the planting pit dug is 50-60 cm.

[0021] By adopting the above technical solution and specifically selecting a planting pit depth of 50-60 cm, it is more suitable for planting poplar seedlings, so that the survival rate of the poplar seedlings is higher.

[0022] In summary, this application has the following beneficial effects: 1. Since the present application irrigates the soil at the planting pit with a nutrient solution composed of Portuguese coryspore yeast, tropical candida yeast, xylinum acetobacter, water and nutrients, Portuguese coryspore yeast, tropical candida yeast and xylinum acetobacter are reproduced in large quantities in the soil, and their fermentation products can promote the rooting of poplars and thus improve the survival rate. After the poplars are planted, under the action of high concentrations of Portuguese coryspore yeast, tropical candida yeast and xylinum acetobacter in the soil of the planting pit area, they can have a high survival rate even in the soil with serious mercury and cadmium pollution, reduce the economic losses caused by the withering of poplar seedlings, and effectively control the initial investment costs. When the poplars are mature, they can not only absorb mercury and cadmium in the soil to achieve the effect of soil remediation, but also cut down the poplars. Although the heavy metals in the poplars planted in this way will exceed the standard, after the wood is processed, not only the wood resources are utilized, but also the heavy metals can be recovered, which can generate considerable economic benefits, thereby reducing the cost of controlling soil heavy metal pollution to a certain extent, so that the control process applied to soil heavy metal pollution can be better promoted.

[0023] 2. In the present application, it is preferred to specifically select the mass ratio of Portuguese Corynespora, tropical Candida, Acetobacter xylinum, water, and nutrients so that the nutrient solution can play a better role in improving the survival rate of poplars while effectively controlling costs, thereby having a higher economic value.

[0024] 3. In the present application, it is preferred to specifically select nutrients such as Physalis juice, Pyracantha juice, Raspberry juice, glucose, peptone, potassium chloride, sodium chloride, and vitamin C to allow Portuguese Coryspore yeast, tropical Candida, and Acetobacter xylinum to reproduce rapidly and increase the bacterial concentration rapidly, thereby rapidly increasing the concentration of Portuguese Coryspore yeast, tropical Candida, and Acetobacter xylinum in the soil at the planting pit, thereby improving the survival rate of poplar trees.

[0025] 4. In the present application, it is preferred that the mass ratio of Physalis juice, Pyracantha fortuneana juice, Raspberry juice, glucose, peptone, potassium chloride, sodium chloride and vitamin C be specifically selected to accelerate the reproduction of Portuguese Corysporum, Tropical Candida and Acetobacter xylinum, and the quality of the nutrient solution is better, which can better improve the survival rate of poplars. DETAILED DESCRIPTION

[0026] The present application is further described in detail below with reference to the embodiments.

[0027] Example 1 A treatment process for heavy metal pollution in soil, comprising the following steps: Step 1) locates and marks the poplar planting site on the contaminated soil. The marked area is consistent with the plane shape and size of the planting pit required for planting, specifically a square with a length of 50 cm and a width of 50 cm.

[0028] Step 2), vertically insert water-stop fences along the four sides of the square of the marked area to completely surround the marked area, and the insertion depth of the water-stop fence is 1m.

[0029] Step 3), pour 100 kg of nutrient solution on the marked area and wait for 7 days.

[0030] Step 4), remove the water-stop enclosure, dig a planting pit with a size of 50 cm in length, 50 cm in width and 50 cm in depth, then plant the poplar saplings, and then backfill all the soil dug out from the planting pit into the planting pit. After the planting pit is filled, continue to backfill to form a small arched soil bag, and continue watering for 30 days, watering each poplar sapling with 500 mL of water every day. After 30 days, no care is needed, and the poplar saplings are allowed to grow naturally. After the poplars survive, they absorb mercury and cadmium in the soil to achieve the effect of purifying the soil.

[0031] The poplar saplings were purchased from Shuyang Wanxiang Flower and Tree Planting Professional Cooperative, poplar saplings, variety: 107 fast-growing poplar, with a breast diameter of about 3cm, a trunk height of about 3m, and a tree age of 2 years.

[0032] The nutrient solution is a compound of Portuguese Corysporum, tropical Candida, Acetobacter xylinum, water and nutrients.

[0033] Portuguese yeast was purchased from Beijing Bio-Bowei Biotechnology Co., Ltd. with the number: Bio-091577.

[0034] Candida tropicalis was purchased from Beijing Bio-Bowei Biotechnology Co., Ltd. with the number: Bio-67426.

[0035] Acetobacter xylinum was purchased from Beijing Biobo Biotechnology Co., Ltd. with the number: 72727.

[0036] The nutrients are a combination of Physalis juice, Pyracantha juice, Raspberry juice, glucose, peptone, potassium chloride, sodium chloride and vitamin C.

[0037] Physalis juice is made by squeezing freshly picked physalis berries through a juicer.

[0038] Pyracantha juice is obtained by squeezing freshly picked Pyracantha fruits through a juicer.

[0039] The grape juice is obtained by squeezing the freshly picked grape berries through a juicer.

[0040] Glucose was purchased from Zhengzhou Yuhe Food Additive Co., Ltd., CAS No.: 50-99-7.

[0041] Peptone was purchased from Hubei Xinghengye Technology Co., Ltd., CAS No.: 73049-73-7.

[0042] Potassium chloride was purchased from Zhengzhou Yuhe Food Additive Co., Ltd., CAS No.: 7447-40-7.

[0043] Sodium chloride was purchased from Jiangsu Boquan Biotechnology Co., Ltd., CAS number: 7647-14-5.

[0044] Vitamin C is commercially available, CAS number: 50-81-7.

[0045] The preparation method of nutrient solution is as follows: 1000kg of water, 1kg of Physalis juice, 2kg of Pyracantha fortuneana juice, 5kg of Vitis vinifera juice, 2kg of glucose, 2kg of peptone, 0.5kg of potassium chloride, 0.5kg of sodium chloride and 0.2kg of vitamin C were put into a stirring tank at a speed of 120r / min. The mixture was stirred for 5min and mixed evenly. Then, 0.012kg of Portuguese Corynespora yeast, 0.007kg of tropical Candida albicans and 0.015kg of Acetobacter xylinum were added and cultured at a constant temperature of 35°C for 4 days to obtain a nutrient solution.

[0046] Example 2 A treatment process for heavy metal pollution in soil, comprising the following steps: Step 1) locates and marks the poplar planting site on the contaminated soil. The marked area is consistent with the plane shape and size of the planting pit required for planting, specifically a square with a length of 50 cm and a width of 50 cm.

[0047] Step 2), vertically insert water-stop fences along the four sides of the square of the marked area to completely surround the marked area, and the insertion depth of the water-stop fence is 1.25m.

[0048] Step 3), pour 112.5 kg of nutrient solution on the marked area and wait for 7.5 days.

[0049] Step 4), remove the water-stop enclosure, dig a planting pit with a size of 50 cm in length, 50 cm in width and 55 cm in depth, then plant the poplar saplings, and then backfill all the soil dug out from the planting pit into the planting pit. After the planting pit is filled, continue to backfill to form a small arched soil bag, and continue watering for 30 days, watering each poplar sapling with 500 mL of water every day. After 30 days, no care is needed, and the poplar saplings are allowed to grow naturally. After the poplars survive, they absorb mercury and cadmium in the soil to achieve the effect of purifying the soil.

[0050] The poplar saplings were purchased from Shuyang Wanxiang Flower and Tree Planting Professional Cooperative, poplar saplings, variety: 107 fast-growing poplar, with a breast diameter of about 3cm, a trunk height of about 3m, and a tree age of 2 years.

[0051] The nutrient solution is a compound of Portuguese Corysporum, tropical Candida, Acetobacter xylinum, water and nutrients.

[0052] Portuguese yeast was purchased from Beijing Bio-Bowei Biotechnology Co., Ltd. with the number: Bio-091577.

[0053] Candida tropicalis was purchased from Beijing Bio-Bowei Biotechnology Co., Ltd. with the number: Bio-67426.

[0054] Acetobacter xylinum was purchased from Beijing Biobo Biotechnology Co., Ltd. with the number: 72727.

[0055] The nutrients are a combination of Physalis juice, Pyracantha juice, Raspberry juice, glucose, peptone, potassium chloride, sodium chloride and vitamin C.

[0056] Physalis juice is made by squeezing freshly picked physalis berries through a juicer.

[0057] Pyracantha juice is obtained by squeezing freshly picked Pyracantha fruits through a juicer.

[0058] The grape juice is obtained by squeezing the freshly picked grape berries through a juicer.

[0059] Glucose was purchased from Zhengzhou Yuhe Food Additive Co., Ltd., CAS No.: 50-99-7.

[0060] Peptone was purchased from Hubei Xinghengye Technology Co., Ltd., CAS No.: 73049-73-7.

[0061] Potassium chloride was purchased from Zhengzhou Yuhe Food Additive Co., Ltd., CAS No.: 7447-40-7.

[0062] Sodium chloride was purchased from Jiangsu Boquan Biotechnology Co., Ltd., CAS number: 7647-14-5.

[0063] Vitamin C is commercially available, CAS number: 50-81-7.

[0064] The preparation method of nutrient solution is as follows: 1000kg of water, 1.5kg of Physalis juice, 2.5kg of Pyracantha fortuneana juice, 5.5kg of Vitis vinifera juice, 2.5kg of glucose, 2.5kg of peptone, 0.55kg of potassium chloride, 0.55kg of sodium chloride and 0.25kg of vitamin C were put into a stirring tank at a speed of 120r / min. The mixture was stirred for 5min and mixed evenly. Then, 0.013kg of Portuguese Corynespora yeast, 0.008kg of tropical Candida albicans and 0.016kg of Acetobacter xylinum were added and cultured at a constant temperature of 36°C for 4.5 days to obtain a nutrient solution.

[0065] Example 3 A treatment process for heavy metal pollution in soil, comprising the following steps: Step 1) locates and marks the poplar planting site on the contaminated soil. The marked area is consistent with the plane shape and size of the planting pit required for planting, specifically a square with a length of 50 cm and a width of 50 cm.

[0066] Step 2), vertically insert water-stop fences along the four sides of the square of the marked area to completely surround the marked area, and the insertion depth of the water-stop fence is 1.5m.

[0067] Step 3), pour 125kg of nutrient solution on the marked area and wait for 8 days.

[0068] Step 4), remove the water-stop enclosure, dig a planting pit with a size of 50 cm in length, 50 cm in width and 60 cm in depth, then plant the poplar saplings, and then backfill all the soil dug out from the planting pit into the planting pit. After the planting pit is filled, continue to backfill to form a small arched soil bag, and continue watering for 30 days, watering each poplar sapling with 500 mL of water every day. After 30 days, no care is needed, and the poplar saplings are allowed to grow naturally. After the poplars survive, they absorb mercury and cadmium in the soil to achieve the effect of purifying the soil.

[0069] The poplar saplings were purchased from Shuyang Wanxiang Flower and Tree Planting Professional Cooperative, poplar saplings, variety: 107 fast-growing poplar, with a breast diameter of about 3cm, a trunk height of about 3m, and a tree age of 2 years.

[0070] The nutrient solution is a compound of Portuguese Corysporum, tropical Candida, Acetobacter xylinum, water and nutrients.

[0071] Portuguese yeast was purchased from Beijing Bio-Bowei Biotechnology Co., Ltd. with the number: Bio-091577.

[0072] Candida tropicalis was purchased from Beijing Bio-Bowei Biotechnology Co., Ltd. with the number: Bio-67426.

[0073] Acetobacter xylinum was purchased from Beijing Biobo Biotechnology Co., Ltd. with the number: 72727.

[0074] The nutrients are a combination of Physalis juice, Pyracantha juice, Raspberry juice, glucose, peptone, potassium chloride, sodium chloride and vitamin C.

[0075] Physalis juice is made by squeezing freshly picked physalis berries through a juicer.

[0076] Pyracantha juice is obtained by squeezing freshly picked Pyracantha fruits through a juicer.

[0077] The grape juice is obtained by squeezing the freshly picked grape berries through a juicer.

[0078] Glucose was purchased from Zhengzhou Yuhe Food Additive Co., Ltd., CAS No.: 50-99-7.

[0079] Peptone was purchased from Hubei Xinghengye Technology Co., Ltd., CAS No.: 73049-73-7.

[0080] Potassium chloride was purchased from Zhengzhou Yuhe Food Additive Co., Ltd., CAS No.: 7447-40-7.

[0081] Sodium chloride was purchased from Jiangsu Boquan Biotechnology Co., Ltd., CAS number: 7647-14-5.

[0082] Vitamin C is commercially available, CAS number: 50-81-7.

[0083] The preparation method of nutrient solution is as follows: 1000kg of water, 2kg of Physalis juice, 3kg of Pyracantha fortuneana juice, 6kg of Vitis vinifera juice, 3kg of glucose, 3kg of peptone, 0.6kg of potassium chloride, 0.6kg of sodium chloride and 0.3kg of vitamin C were put into a stirring tank at a speed of 120r / min. The mixture was stirred for 5min and mixed evenly. Then, 0.014kg of Portuguese Corynespora yeast, 0.009kg of tropical Candida albicans and 0.017kg of Acetobacter xylinum were added and cultured at a constant temperature of 37°C for 5 days to obtain a nutrient solution.

[0084] Comparative Example 1 A treatment process for heavy metal pollution in soil, compared with Example 2, the only difference is: In the nutrient solution, Bacillus subtilis was used to replace Portuguese yeast in equal amounts.

[0085] Bacillus subtilis was purchased from Beijing Biobio Biotechnology Co., Ltd. with the number: Bio-72808.

[0086] Comparative Example 2 A treatment process for heavy metal pollution in soil, compared with Example 2, the only difference is: In the nutrient solution, Bacillus megaterium was used to replace Candida tropicalis in equal amounts.

[0087] Bacillus megaterium was purchased from Beijing Biobio Biotechnology Co., Ltd. with the number: Bio-74912.

[0088] Comparative Example 3 A treatment process for heavy metal pollution in soil, compared with Example 2, the only difference is: In the nutrient solution, an equal amount of Bacillus licheniformis was used to replace Acetobacter xylinum.

[0089] Bacillus licheniformis was purchased from Beijing Biobio Biotechnology Co., Ltd. with the license number Bio-67637.

[0090] Comparative Example 4 A treatment process for heavy metal pollution in soil, compared with Example 2, the only difference is: In the nutrient solution, Bacillus subtilis was used to replace Portuguese yeast in an equal amount, Bacillus megaterium was used to replace tropical Candida, and Bacillus licheniformis was used to replace Acetobacter xylinum in an equal amount.

[0091] Bacillus subtilis was purchased from Beijing Biobio Biotechnology Co., Ltd. with the number: Bio-72808.

[0092] Bacillus megaterium was purchased from Beijing Biobio Biotechnology Co., Ltd. with the number: Bio-74912.

[0093] Bacillus licheniformis was purchased from Beijing Biobio Biotechnology Co., Ltd. with the license number Bio-67637.

[0094] Comparative Example 5 A treatment process for heavy metal pollution in soil, compared with Example 2, the only difference is: In the nutrient solution, replace the Physalis juice with an equal amount of apple juice.

[0095] Apple juice is made by squeezing freshly picked apples through a juicer.

[0096] Comparative Example 6 A treatment process for heavy metal pollution in soil, compared with Example 2, the only difference is: In the nutrient solution, replace the Pyracantha juice with an equal amount of snow pear juice.

[0097] Snow pear juice is obtained by squeezing the juice from freshly picked snow pears through a juicer.

[0098] Comparative Example 7 A treatment process for heavy metal pollution in soil, compared with Example 2, the only difference is: In the nutrient solution, replace the grape juice with an equal amount of carrot juice.

[0099] Carrot juice is made by squeezing freshly picked carrots through a juicer.

[0100] Comparative Example 8 A treatment process for heavy metal pollution in soil, compared with Example 2, the only difference is: In the nutrient solution, use an equal amount of apple juice to replace the Physalis juice, an equal amount of pear juice to replace the Pyracantha juice, and an equal amount of carrot juice to replace the Pyracantha juice.

[0101] Apple juice is made by squeezing freshly picked apples through a juicer.

[0102] Snow pear juice is obtained by squeezing the juice from freshly picked snow pears through a juicer.

[0103] Carrot juice is made by squeezing freshly picked carrots through a juicer.

[0104] Experiment 1 Mercury and cadmium contaminated soil were selected as test fields. The mercury content in the soil of the test fields was 50 mg / kg and the cadmium content was 100 mg / kg.

[0105] Poplar seedlings were planted in the test field using the treatment processes for heavy metal pollution in soil of the embodiments and comparative examples.

[0106] 1000 plants were planted in each embodiment and comparative example, with each plant spaced 3 m apart, 100 seedlings were grouped into a group, 10 m apart were left between groups, and each group was randomly distributed in the test field.

[0107] After completing the step of watering for 30 days, wait for another 30 days, count the number of seedlings with new leaves sprouting in each group of 100 seedlings, calculate the survival rate, and take the average of the survival rates of the 10 groups of seedlings in each embodiment and comparative example.

[0108] Survival rate (%) = number of seedlings with new leaves sprouting ÷ 100 × 100.

[0109] The specific test data of Experiment 1 are shown in Table 1.

[0110] Table 1 Poplar seedling survival rate (%) Example 1 96.3 Example 2 97.4 Example 3 95.8 Comparative Example 1 82.7 Comparative Example 2 83.5 Comparative Example 3 81.9 Comparative Example 4 81.1 Comparative Example 5 91.6 Comparative Example 6 92.4 Comparative Example 7 91.9 Comparative Example 8 90.7 According to the data comparison of each embodiment and comparative example in Table 1, it can be obtained that the survival rate of each embodiment is significantly higher than that of each comparative example, and is as high as 95.8-97.4%, which can effectively reduce the economic losses caused by the failure of seedlings to survive.

[0111] In Comparative Examples 1-4, other microorganisms with root-promoting effects were used to replace the Portuguese coryneformis, tropical Candida, and xylinum in the examples alone or in whole. Although they can also promote the rooting of poplar seedlings to a certain extent, the survival rate is significantly lower than that of the examples. It can be seen that the special combination of Portuguese coryneformis, tropical Candida, and xylinum in the examples can play a better synergistic role and can better improve the survival rate of poplar seedlings.

[0112] In comparative examples 5-8, other juices were used to replace the Physalis juice, Pyracantha juice, and Vitis vinifera juice in the embodiment alone or in whole, resulting in a small decrease in the survival rate. It can be seen that the selection of a compound of Physalis juice, Pyracantha juice, and Vitis vinifera juice in nutrients helps to improve the activity of Portuguese Corysporum, Tropical Candida, and Xylinum Acetobacter, so that the concentrations of Portuguese Corysporum, Tropical Candida, and Xylinum Acetobacter in the contaminated soil are higher, thereby better promoting the rooting of poplar seedlings through their secretion products, so that the survival rate of poplar seedlings is higher, and the economic value is higher.

[0113] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but such modifications are protected by patent law as long as they are within the scope of the claims of the present application.

Claims

1. A process for treating heavy metal pollution in soil, characterized in that: The following steps are involved: Step 1) locate and mark the poplar planting site on the contaminated soil. The marked area should be consistent with the plane shape and size of the planting pit required for planting. Step 2), insert a water-stop fence into the marked area to completely surround the marked area; Step 3) Pour nutrient solution into the marked area and let it sit for 7-8 days; Step 4), remove the water-stop enclosure, dig a planting pit, plant the poplar saplings, and then backfill all the soil dug out of the planting pit, waiting for the poplars to grow and purify the soil; The nutrient solution is a compound of Portuguese corynespora yeast, tropical candida, xylinum acetobacter, water and nutrients.

2. The process for treating heavy metal pollution in soil according to claim 1, characterized in that: In the nutrient solution, the mass ratio of Portuguese coryneformis, tropical candida, xylinum acetobacter, water and nutrients is 0.012-0.014: 0.007-0.009: 0.015-0.017: 1000: 13.2-18.

5.

3. The process for treating heavy metal pollution in soil according to claim 2, characterized in that: The nutrients in the nutrient solution are a compound of Physalis juice, Pyracantha fortuneana juice, Raspberry juice, glucose, peptone, potassium chloride, sodium chloride and vitamin C.

4. The process for treating heavy metal pollution in soil according to claim 3, characterized in that: Among the nutrients, the mass ratios of Physalis juice, Pyracantha fortuneana juice, Raspberry juice, glucose, peptone, potassium chloride, sodium chloride and vitamin C are 1-2: 2-3: 5-6: 2-3: 2-3: 0.5-0.6: 0.5-0.6: 0.2-0.

3.

5. The process for treating heavy metal pollution in soil according to claim 4, characterized in that: The preparation method of the nutrient solution is as follows: Mix water and nutrients evenly, then add Portuguese Corynespora yeast, tropical Candida, and Acetobacter xylinum, and culture at a constant temperature of 35-37°C for 4-5 days to obtain a nutrient solution.

6. The process for treating heavy metal pollution in soil according to claim 1, characterized in that: In the step 2), the insertion depth of the water stop enclosure is 1-1.5m.

7. The process for treating heavy metal pollution in soil according to claim 1, characterized in that: In the step 3), when watering the nutrient solution, every 1m 2 Water the soil area with 400-500kg of nutrient solution.

8. The process for treating heavy metal pollution in soil according to claim 1, characterized in that: In step 4), the depth of the planting pit dug is 50-60 cm.