A soil ecological restoration method for rural garbage storage sites

Abstract

The invention relates to the technical field of soil restoration, and specifically provides a method for soil ecological restoration of a rural garbage storage site, which specifically comprises the following steps: step one, garbage classification and targeted treatment; step two, soil sampling and land classification; step three, plowing the unpolluted land, applying base fertilizer, sowing, introducing insects, and placing beehives; step four, plowing the polluted land, applying quicklime, turning the soil, applying organic acid after 7-10 days, spraying organic acid solution in the air, and applying soil conditioner; step five, applying decomposed organic fertilizer, planting forage grass, edible fungi and shrub plants; step six, introducing poultry and livestock until the land is pollution-free; the soil restored by the method of the invention is basically close to the level of primary agricultural land.

Description

Technical Field

[0001] The present invention relates to the technical field of soil restoration, and in particular to a method for ecological restoration of soil at a rural garbage dump site. Background Art

[0002] At present, most countries in the world mainly deal with domestic waste by centrally piling up garbage and then landfilling it. However, the large amount of garbage dumped in the landfill also brings many negative effects. First of all, the garbage dump occupies the limited land resources in the suburbs. Secondly, in rural areas with weaker management, there are even some garbage dumps that are not scientifically designed and protected, and all kinds of garbage are directly buried or piled in the open air. From the perspective of environmental protection, the transformation and treatment of garbage dumps can not only reduce pollution, but also restore the ecological environment and promote the sustainable development of rural areas. Therefore, the current restoration of the land of garbage dumps is of great significance to the development of rural areas.

[0003] At present, the methods for repairing garbage dumps include landfill, soil leaching, solidification / stabilization, high-temperature thermal desorption and ecological restoration. However, the above methods have their own shortcomings. Although landfill technology is mature and the processing speed is fast, it is not easy to find a large landfill to cooperate. Moreover, garbage landfill will also cause certain pollution to the environment. Soil leaching not only requires a large amount of water, but also requires supporting wastewater treatment facilities to treat leaching wastewater. Improper treatment may cause secondary pollution. The most important thing is that it needs to be leached multiple times to achieve the treatment effect. The treatment cost is high, which is difficult for some rural areas with weak economic foundations to bear. Although solidification / stabilization can quickly fix heavy metal ions in the soil, it has limited effect on volatile organic compounds in the soil, and the soil volume increases after treatment, which limits the secondary use of the soil. High-temperature thermal desorption has excellent effects on volatile organic compounds in the soil, but has limited effects on heavy metal ions in the soil. The construction cost of ecological restoration is low, suitable for rural areas, and does not affect the secondary use of the soil, but the treatment time is long.

[0004] Therefore, providing an economical and applicable soil remediation method that can quickly restore the ecology has become an urgent issue to be addressed. Summary of the invention

[0005] In order to solve the above problems, the present invention provides a method for ecological restoration of soil in rural garbage storage sites, which specifically comprises the following steps:

[0006] Step 1: Classify the garbage stored in the garbage dump, and then carry out targeted treatment according to the garbage classification;

[0007] Step 2: Sampling soil from different plots of the landfill, testing the soil samples, and dividing the plots into contaminated plots and non-contaminated plots according to the test results of the soil samples;

[0008] Step 3: directly till the unpolluted land to a depth of 20-30cm, apply basal fertilizer along with tillage, sow 8-10kg / mu of herb seeds and 3-4kg / mu of shrub seeds, and introduce insects after the herb and shrub plants emerge, with an insect density of 8-10 / m 2 , and place beehives in the plots, with a density of 0.5-1 beehives per mu;

[0009] Step 4: plough the contaminated land to a depth of 20-30cm, apply quicklime at a dosage of 80-100kg / mu, then irrigate the soil to a moisture content of 10-20%, turn the soil every 2-3 days to a depth of 10-15cm, and after 7-10 days, apply organic acid to the soil to adjust the soil pH to 6-8, and spray the organic acid solution in the air every 2-3 days at a dosage of 10-15ml / m 2 , 7-10 days later, apply soil conditioner to the soil at a dosage of 100-120kg / mu;

[0010] Step 5: After standing for 10-15 days, apply decomposed organic fertilizer to the contaminated land at a rate of 90-100 kg / mu, sow 5-10 kg / mu of forage seeds, 6-7 kg / mu of edible mushroom sticks and 3-4 kg / mu of shrub seeds, and then water the soil to a moisture content of 50-70%;

[0011] Step six: When the grass matures, introduce 100-200 poultry / mu and 2-5 livestock / mu. The poultry and livestock manure will not be treated until the land is free of pollution.

[0012] Preferably, the targeted treatment in step one is to send recyclable waste to a recycling station for recycling, send hazardous waste to a hazardous waste treatment plant, compost domestic waste, or make activated carbon.

[0013] Preferably, the classification criteria for the polluted plots and the non-polluted plots in step 2 are:

[0014] Standard 1: As ≥ 40 mg / kg;

[0015] Standard 2: Cd ≥ 0.6 mg / kg;

[0016] Standard 3: Cr ≥ 400 mg / kg;

[0017] Standard 4: Ni ≥ 200 mg / kg;

[0018] Standard 5: Pd ≥ 500 mg / kg;

[0019] When the soil meets any of the criteria 1-5, it is considered a polluted plot; when the soil does not meet any of the criteria 1-5, it is considered an unpolluted plot.

[0020] Preferably, the application amount of the base fertilizer in step three is 100-120 kg / mu, and the base fertilizer includes 15-15-15 compound fertilizer and decomposed organic fertilizer in a mass ratio of 1:9; the decomposed organic fertilizer is decomposed feces or decomposed straw.

[0021] Preferably, the herbaceous plants in step three are one or more of astragalus, violet, dandelion, foxtail grass, morning glory and impatiens; the shrubby plants are one or more of Amorpha fruticosa, purple magnolia, gardenia, rose, azalea and Chinese rose.

[0022] Preferably, the insects in step three are one or more of grasshoppers, crickets, watermelon worms, butterflies, bees and silkworms.

[0023] Preferably, the organic acid is one or more of acetic acid, citric acid, malic acid and sorbic acid; the organic acid solution is based on water and includes 200-300 g / L acetic acid and 100-200 g / L citric acid.

[0024] Preferably, the soil conditioner includes humus, bentonite, river sand, activated carbon, alumina, zeolite, vermiculite and quartz sand in a mass ratio of 80:30:10:5:1:3:2:4.

[0025] Preferably, the decomposed organic fertilizer in step five is decomposed straw or decomposed feces; the forage grass is one or more of alfalfa, ryegrass, corn grass, sheep grass and king grass; the edible fungi are one or more of mushrooms, shiitake mushrooms, enoki mushrooms, oyster mushrooms, black fungus and white fungus; the shrub plants are one or more of Amorpha fruticosa, purple magnolia, gardenia, rose, azalea and Chinese rose.

[0026] Preferably, the poultry in step six is ​​one or more of chicken, duck and goose, and the livestock is one or more of cattle, sheep and pig.

[0027] The present invention has the following advantages:

[0028] (1) The present invention classifies garbage and processes non-recyclable garbage such as kitchen waste and domestic waste, and composts or prepares activated carbon. The prepared organic fertilizer and activated carbon can be used for subsequent soil remediation, resource recycling, cost saving and efficiency improvement.

[0029] (2) The present invention classifies the plots of land and directly carries out planting on the unpolluted plots, thereby sharing the environmental pressure of the polluted plots and carrying out special treatment on the polluted plots, saving restoration costs and maximizing resource utilization.

[0030] (3) The soil in the garbage dump contains a large amount of volatile organic compounds such as halogenated hydrocarbons and benzene series, and it also continuously releases gases such as ammonia, hydrogen sulfide and carbon dioxide, which lead to hypoxia in the garbage dump and imbalance of soil pH. Therefore, a large amount of quicklime is applied to the soil and water is applied appropriately. In the process of quicklime and water forming slaked lime, a large amount of heat is released, which increases the ground temperature and separates the volatile organic compounds from the soil. The slaked lime generated by the reaction can further neutralize hydrogen sulfide and carbon dioxide, achieving multiple goals at one stroke. While saving the cost of restoration, it also improves resource utilization.

[0031] (4) Large amounts of quicklime applied will result in high soil pH, causing soil compaction and plant root hypoxia. Therefore, organic acids are applied to adjust soil pH and organic acid solutions are sprayed in the air to neutralize ammonia.

[0032] (5) Setting up beehives in a plot of land can significantly improve the efficiency of pollen propagation, allowing floral plants to spread faster to surrounding plots and build a small ecosystem.

[0033] (6) Planting forage grass and edible mushroom sticks in polluted land can quickly enrich heavy metal ions in the soil, introduce insects, poultry and livestock, build a small ecosystem, and restore the soil ecology with the environment's own regulatory function. In addition, forage grass, edible mushrooms, poultry and livestock can also generate secondary economic benefits to offset construction costs and significantly reduce restoration costs. This is suitable for rural areas with a relatively weak economic foundation.

[0034] (7) In the early stage of treatment, the present invention first applies a small amount of soil conditioner to quickly fix pollutants in the soil, prevent them from spreading to surrounding areas, and reduce the pressure of soil restoration. On the basis of the early rapid treatment, a small ecosystem is constructed according to local conditions, thereby achieving the purpose of being both economical and able to quickly repair the soil. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the invention, not all of the embodiments. Based on the embodiments of the invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the invention.

[0036] Example 1

[0037] Step 1: Select a local garbage storage site, send recyclable garbage (cans, plastic products, glass products, etc.) to the recycling station for recycling, send hazardous waste (lead-acid batteries, pesticides and their packaging, etc.) to the hazardous waste treatment plant, and use waste paper, bamboo sticks, bamboo chopsticks, textiles, etc. in domestic garbage as raw materials to prepare activated carbon; compost leftovers, melon and fruit peels, vegetable leaves, and meat products in domestic garbage.

[0038] When preparing activated carbon, except for the raw materials, the preparation method refers to "Study on the Preparation and Adsorption Performance of Activated Carbon from Crop Waste", Xu Xianyang, Huang Weiqiu, etc.

[0039] When composting, in addition to the raw materials, the composting process refers to "Analysis on the Production Technology of Organic Fertilizer Prepared from Kitchen Waste", Zhan Zhengyan, Gu Shengfang, etc.

[0040] Step 2: Sampling soil from different plots of the landfill at a depth of 30 cm, and testing the soil samples. The results are shown in Table 1; Plot 1 is the garbage dump, Plot 3 is the non-garbage dump, and Plot 2 is the transition zone between the garbage dump and the non-garbage dump.

[0041] The classification standards for polluted and non-polluted plots are:

[0042] Standard 1: As ≥ 40 mg / kg;

[0043] Standard 2: Cd ≥ 0.6 mg / kg;

[0044] Standard 3: Cr ≥ 400 mg / kg;

[0045] Standard 4: Ni ≥ 200 mg / kg;

[0046] Standard 5: Pd ≥ 500 mg / kg;

[0047] When the soil meets any of the criteria 1-5, it is considered a polluted plot; when the soil does not meet any of the criteria 1-5, it is considered an unpolluted plot.

[0048] Table 1 Heavy metal ion content of soil in different plots of landfill before treatment

[0049]

[0050] Step 3: Plot 3 was tilled to a depth of 25 cm. Along with the tillage, 12 kg / mu of 15-15-15 compound fertilizer and 108 kg / mu of decomposed straw were applied. 9 kg / mu of herb seeds and 3 kg / mu of shrub seeds were sown. When the herb and shrub plants emerged, insects were introduced at a density of 8 insects / m 2 , and place beehives in the plots, with a beehive density of 1 per mu;

[0051] The herbaceous plant seeds are astragalus seeds, violet seeds, morning glory and dandelion seeds, with a mass ratio of 1:1:1:1.

[0052] The shrub plant seeds are gardenia seeds, rose seeds and azalea seeds, with a mass ratio of 1:1:1.

[0053] Step 4: Plow plots 2 and 3 to a depth of 25 cm, apply quicklime at a rate of 90 kg / mu, and then water the soil to a moisture content of 15%. Plow the soil every 2 days to a depth of 12 cm. After 8 days, apply organic acid to the soil to adjust the soil pH to 6-8. Spray the organic acid solution in the air every 3 days at a rate of 13 ml / m 2 , 8 days later, apply soil conditioner to the soil at a dosage of 120kg / mu;

[0054] The organic acids are acetic acid and citric acid in a mass ratio of 1:1;

[0055] The organic acid solution is based on water and includes 200 g / L acetic acid and 100 g / L citric acid;

[0056] The soil conditioner includes humus, bentonite, river sand, activated carbon, alumina, zeolite, vermiculite and quartz sand in a mass ratio of 80:30:10:5:1:3:2:4.

[0057] Step 5. After standing for 12 days, apply 100 kg / mu of decomposed manure to the contaminated land, and sow 7 kg / mu of forage seeds, 6 kg / mu of edible mushroom sticks and 3 kg / mu of shrub seeds, and then irrigate the soil to a moisture content of 65%.

[0058] The forage seeds are alfalfa seeds, ryegrass seeds and chinensis seeds, with a mass ratio of 1:1:1;

[0059] The edible mushroom sticks are mushroom sticks, shiitake mushroom sticks and enoki mushroom sticks, with a mass ratio of 1:1:1;

[0060] The shrub plant seeds are gardenia seeds, rose seeds, azalea seeds and rose seeds, and the mass ratio is 1:1:1:1.

[0061] Step six, when the grass matures, 80 chickens / mu, 40 ducks / mu, 1 cow / mu and 3 sheep / mu are introduced. The manure of poultry and livestock is not treated. One year later, the heavy metal ion content of plots 1 to 3 is tested respectively. The results are shown in Table 2.

[0062] Table 2 Heavy metal ion content of soil from different plots of landfill after treatment

[0063]

[0064] As shown in Table 1-2, after one year of ecological management, the heavy metal ions in plots 1 and 2 were significantly reduced, and the heavy metal ions in plot 3 were also reduced. The heavy metal ions in plots 1, 2 and 3 were close to the level of primary agricultural land, which shows that the ecological management method provided by the present invention is highly practical and effective.

[0065] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for ecological restoration of soil at a rural garbage dump site, characterized in that: The following steps are involved: Step 1: Classify the garbage stored in the garbage dump, and then carry out targeted treatment according to the garbage classification; Step 2: Sampling soil from different plots of the landfill, testing the soil samples, and dividing the plots into contaminated plots and non-contaminated plots according to the test results of the soil samples; Step 3: directly till the unpolluted land to a depth of 20-30cm, apply basal fertilizer along with tillage, sow 8-10kg / mu of herb seeds and 3-4kg / mu of shrub seeds, and introduce insects after the herb and shrub plants emerge, with an insect density of 8-10 / m 2 , and place beehives in the plots, with a density of 0.5-1 beehives per mu; Step 4: plough the contaminated land to a depth of 20-30cm, apply quicklime at a dosage of 80-100kg / mu, then irrigate the soil to a moisture content of 10-20%, turn the soil every 2-3 days to a depth of 10-15cm, and after 7-10 days, apply organic acid to the soil to adjust the soil pH to 6-8, and spray the organic acid solution in the air every 2-3 days at a dosage of 10-15ml / m 2 , 7-10 days later, apply soil conditioner to the soil at a dosage of 100-120kg / mu; Step 5: After standing for 10-15 days, apply decomposed organic fertilizer to the contaminated land at a rate of 90-100 kg / mu, sow 5-10 kg / mu of forage seeds, 6-7 kg / mu of edible mushroom sticks and 3-4 kg / mu of shrub seeds, and then water the soil to a moisture content of 50-70%; Step six: When the grass matures, introduce 100-200 poultry / mu and 2-5 livestock / mu. The poultry and livestock manure will not be treated until the land is free of pollution.

2. A method for ecological restoration of soil at a rural garbage dump site according to claim 1, characterized in that: The targeted treatment described in step one is to send recyclable garbage to a recycling station for recycling, send hazardous waste to a hazardous waste treatment plant, compost domestic waste, or make it into activated carbon.

3. A method for ecological restoration of soil at a rural garbage dump site according to claim 1, characterized in that: The classification criteria for polluted and non-polluted plots in step 2 are: Standard 1: As ≥ 40 mg / kg; Standard 2: Cd ≥ 0.6 mg / kg; Standard 3: Cr ≥ 400 mg / kg; Standard 4: Ni ≥ 200 mg / kg; Standard 5: Pd ≥ 500 mg / kg; When the soil meets any of the criteria 1-5, it is considered a polluted plot; when the soil does not meet any of the criteria 1-5, it is considered an unpolluted plot.

4. The method for ecological restoration of soil at a rural garbage dump site according to claim 1, characterized in that: The application amount of the base fertilizer in step three is 100-120 kg / mu, and the base fertilizer includes 15-15-15 compound fertilizer and decomposed organic fertilizer in a mass ratio of 1:9; the decomposed organic fertilizer is decomposed feces or decomposed straw.

5. The method for ecological restoration of soil at a rural garbage dump site according to claim 1, characterized in that: The herbaceous plants in step three are one or more of astragalus, violet, dandelion, foxtail grass, morning glory and impatiens; the shrubby plants are one or more of Amorpha fruticosa, purple magnolia, gardenia, rose, azalea and Chinese rose.

6. A method for ecological restoration of soil at a rural garbage dump site according to claim 1, characterized in that: The insects in step 3 are one or more of grasshoppers, crickets, watermelon worms, butterflies, bees and silkworms.

7. A method for ecological restoration of soil at a rural garbage dump site according to claim 1, characterized in that: The organic acid is one or more of acetic acid, citric acid, malic acid and sorbic acid; the organic acid solution is based on water and includes 200-300 g / L of acetic acid and 100-200 g / L of citric acid.

8. The method for ecological restoration of soil at a rural garbage dump site according to claim 1, characterized in that: The soil conditioner includes humus, bentonite, river sand, activated carbon, alumina, zeolite, vermiculite and quartz sand in a mass ratio of 80:30:10:5:1:3:2:

4.

9. The method for ecological restoration of soil at a rural garbage dump site according to claim 1, characterized in that: The decomposed organic fertilizer in step five is decomposed straw or decomposed feces; the forage grass is one or more of alfalfa, ryegrass, corn grass, sheep grass and king grass; the edible fungi are one or more of mushrooms, shiitake mushrooms, enoki mushrooms, oyster mushrooms, black fungus and white fungus; the shrub plants are one or more of Amorpha fruticosa, purple magnolia, gardenia, rose, azalea and Chinese rose.

10. The method for ecological restoration of soil in rural garbage dump sites according to claim 1, characterized in that: The poultry in step six is ​​one or more of chicken, duck and goose, and the livestock is one or more of cattle, sheep and pig.

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