A method for preparing seedling medium by treating rice husk with acidic mine wastewater and its application

Abstract

The invention discloses a method for preparing a seedling medium by treating rice husk with acid mine wastewater and its application, belonging to the field of environmental protection technology and seedling medium preparation technology. The invention first pre-treats the acid mine wastewater; then treats the rice husk with the pre-treated acid mine wastewater, and finally prepares the medium with the treated rice husk. The invention improves the functionality of rice husk by treating the acid mine wastewater, and uses it to prepare an environmentally friendly and efficient seedling medium, solves the environmental pollution problem in the treatment of mine wastewater, and realizes the reuse of agricultural waste rice husk. The method of the invention can not only effectively utilize the acid mine wastewater and rice husk waste, but also reduce the environmental pollution of the waste, which is in line with the concept of circular economy and green agriculture.

Description

Technical Field

[0001] The invention relates to the fields of environmental protection technology and seedling medium preparation technology, and in particular to a method for preparing a seedling medium by treating rice husk with acid mine wastewater and application thereof. Background Art

[0002] Mine wastewater, especially acid mine wastewater, is produced in the process of mining and utilization of mineral resources. With the development and utilization of various mineral resources, a large number of sulfur-containing compounds such as pyrite and pyrrhotite in a stable reducing environment are exposed to an oxidizing environment and react with water, air, etc. The sulfur in the mineral is oxidized and dissolved in the water in an oxidizing environment, so the sulfate ions and other anions in the groundwater increase. The sulfide and cations produced form sulfate, which is the main component of groundwater. Sulfate is a strong acid salt, so it makes the water acidic, and long-term discharge causes serious pollution to the environment.

[0003] Rice husk is an agricultural waste. It is a byproduct of rice processing. In the southern rice-growing areas, a large amount of rice husk is burned every year because it cannot be reasonably utilized. Rice husk has excellent physical and chemical properties and can be used as a good raw material for seedling substrate after processing. Although some seedling substrates have been developed in the prior art, they have not effectively combined wastewater treatment with the resource utilization of agricultural waste.

[0004] Therefore, how to combine the treatment of acid mine wastewater with the resource utilization of rice husks to form an efficient and environmentally friendly seedling medium is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of this, the present invention provides a method and application of preparing a seedling medium by treating rice husk with acidic mine wastewater. The present invention improves the functionality of rice husk by treating acidic mine wastewater, uses it to prepare an environmentally friendly and efficient seedling medium, solves the environmental pollution problem in mine wastewater treatment, and realizes the reuse of agricultural waste rice husk.

[0006] To achieve the above object, the present invention adopts the following technical solution:

[0007] A method for preparing a seedling medium by treating rice husks with acidic mine wastewater comprises the following steps:

[0008] (1) Acid mine drainage pretreatment: limestone, wood chips and rice husks are mixed and added to a sedimentation tank, and then the acid mine drainage is added to the sedimentation tank for neutralization and pH adjustment. Polyaluminium chloride is then added, stirred evenly and allowed to stand to allow heavy metals and suspended solids to settle. Finally, the treated wastewater is filtered through a sand filter;

[0009] (2) Treating rice husks: Pour the pre-treated mining wastewater into a treatment tank, add rice husks, and soak until the wastewater completely covers the rice husks to promote the degradation of organic matter in the rice husks, and then air-dry in a ventilation device to reduce the moisture content in the rice husks to 10-15%, thereby improving the air permeability in the subsequent matrix preparation process;

[0010] (3) Preparation of substrate: Mix the treated rice husk with wood ash, cow dung, earthworms, bentonite and lignin enzyme preparation, pile them into a cone for fermentation, and obtain the seedling substrate after fermentation is completed.

[0011] Furthermore, the mass ratio of the limestone, sawdust and rice husk in step (1) is 1:1:1;

[0012] Preferably, the limestone particle size is less than 0.5 cm.

[0013] The beneficial effect of adopting the above further scheme is that the above combination of the present invention can precipitate dissolved heavy metals in the form of hydroxides, and can also adsorb some heavy metals in the pores formed on the surface of rice husks, and the above raw materials can increase the pH of wastewater.

[0014] Further, the volume ratio of the total amount of the limestone, sawdust and rice husk to the acid mine drainage is 10-15:100;

[0015] The amount of polyaluminium chloride added to each liter of acidic mine wastewater is 100-200 mg.

[0016] Further, during the neutralization in step (1), the pH is adjusted to 5.5-6.5;

[0017] The standing time is 18-24h;

[0018] The filter layer in the sand filter is quartz sand.

[0019] Furthermore, the soaking time in step (2) is 12-18 hours, and the soaking temperature is 25-35°C.

[0020] Furthermore, the air drying temperature in step (2) is 30-35°C and the air volume is 600-800m 3 / h.

[0021] Furthermore, in the mixture of the treated rice husk and wood ash, cow dung, earthworms, bentonite and ligninase preparation described in step (3), wood ash accounts for 5-10% of the total mass of the raw materials, the ligninase preparation accounts for 5-10% of the total mass of the raw materials, and the remainder is a mixture of treated rice husk, cow dung, earthworms and bentonite.

[0022] Among them, the role of wood ash is to adjust the pH to 6.5-7.5.

[0023] Furthermore, the mixture of treated rice husk, cow dung, earthworm and bentonite has a mass ratio of treated rice husk, cow dung, earthworm and bentonite of 3:2:1:1.

[0024] Preferably, the bentonite particle size is less than 0.5 cm.

[0025] Furthermore, the height and width of the fermentation cone in step (3) are both 1.5-2 m;

[0026] The fermentation temperature is 40-60° C., the fermentation time is 21-28 days, the fermentation pH is 6.5-7.5, and the fermentation mixed humidity is 45%-55%.

[0027] Furthermore, the compost is turned every 4-7 days during the fermentation process.

[0028] The beneficial effect of adopting the above further scheme is that the above scheme can ensure uniform fermentation, avoid excessive local temperature, and maintain air permeability.

[0029] The present invention also provides the use of the seedling cultivation matrix prepared by the method for preparing the seedling cultivation matrix by treating rice husk with acidic mine wastewater in tobacco seedling cultivation.

[0030] Compared with the prior art, the present invention has the following beneficial effects:

[0031] (1) The method of the present invention can not only effectively utilize acid mine wastewater and rice husk waste, but also reduce the environmental pollution of the waste to a certain extent, which is in line with the concept of circular economy and green agriculture.

[0032] (2) The organic matter content in the tobacco seedling medium is required to be high. Under acidic conditions, organic matter in rice husks such as lignin, cellulose and hemicellulose may be partially hydrolyzed or decomposed, and the organic nutrients contained in rice husks (such as carbon, nitrogen, phosphorus, etc.) are more easily absorbed and utilized by plants. This has a positive effect on improving the fertility of the seedling medium.

[0033] (3) Tobacco is vulnerable to diseases, so the tobacco seedling medium needs to have a certain degree of disease resistance. Acidic environments inhibit the reproduction of certain pathogens and pests, so treated rice husks may have better resistance to diseases and pests. This allows it to be used as a seedling medium to reduce the incidence of diseases and increase the survival rate of seedlings.

[0034] (4) After acidic wastewater treatment, the pore structure of rice husk changes. The decomposition of some cellulose and lignin in an acidic environment may lead to more pores in the microstructure of rice husk, which helps it provide good air permeability and water retention when used as a seedling medium. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1This is a diagram showing the effect of growing tobacco seedlings in the matrix of Example 1 for 35 days;

[0036] Figure 2 This is a diagram showing the effect of growing tobacco seedlings in the matrix of Example 2 for 35 days;

[0037] Figure 3 This is a diagram showing the effect of growing tobacco seedlings in the matrix of Example 3 for 35 days;

[0038] Figure 4 This is a 35-day effect diagram of growing tobacco seedlings using the matrix of Comparative Example 1;

[0039] Figure 5 This is a diagram showing the effect of growing tobacco seedlings in the matrix of Comparative Example 2 for 35 days. DETAILED DESCRIPTION

[0040] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0041] Example 1

[0042] A method for preparing a seedling medium by treating rice husks with acidic mine wastewater:

[0043] (1) Pretreatment of acid mine drainage: limestone, sawdust and rice husk are mixed in a mass ratio of 1:1:1 and added to a sedimentation tank. The particle size of the limestone is 0.3 cm. Then the acid mine drainage is added to the sedimentation tank for neutralization and the pH is adjusted to 6.0. The volume ratio of the total amount of limestone, sawdust and rice husk to the acid mine drainage is 15:100. Then, polyaluminium chloride is added. The amount of polyaluminium chloride added to each liter of acid mine drainage is 150 mg. After stirring evenly, the mixture is allowed to stand for 24 hours to allow heavy metals and suspended solids to precipitate. Finally, the treated wastewater is filtered through a sand filter.

[0044] (2) Rice husk treatment: Pour the pre-treated mining wastewater into the treatment tank, add rice husks, and soak them at 30°C for 18 hours to promote the degradation of organic matter in the rice husks. Then, air-dry them in a ventilation device at 35°C to reduce the moisture content in the rice husks to 15%. The air volume is 750m / s. 3 / h, thereby improving the gas permeability in the subsequent matrix preparation process;

[0045] (3) Preparation of substrate: Mix the treated rice husk with wood ash, cow dung, earthworms, bentonite and ligninase preparation, wherein the mixture of rice husk, wood ash, cow dung, earthworms, bentonite and ligninase preparation comprises 10% of the total mass of the raw materials by weight of the wood ash, 10% of the total mass of the ligninase preparation and the remainder of the mixture of treated rice husk, cow dung, earthworms and bentonite, wherein the mass ratio of rice husk, cow dung, earthworms and bentonite is 3:2:1:1, and the mixture is piled into a cone with a height and width of 1.5 m. The mixture is fermented at 50°C, pH 7.0 and a fermentation mixture humidity of 50% for 28 days, and the pile is turned over every 7 days during the fermentation process. After the fermentation is completed, a seedling medium is obtained.

[0046] Example 2

[0047] A method for preparing a seedling medium by treating rice husks with acidic mine wastewater:

[0048] (1) Pretreatment of acid mine drainage: limestone, sawdust and rice husk are mixed in a mass ratio of 1:1:1 and added to a sedimentation tank. The particle size of the limestone is 0.3 cm. Then the acid mine drainage is added to the sedimentation tank for neutralization and the pH is adjusted to 6.0. The volume ratio of the total amount of limestone, sawdust and rice husk to the acid mine drainage is 10:100. Then, polyaluminium chloride is added. The amount of polyaluminium chloride added to each liter of acid mine drainage is 150 mg. After stirring evenly, the mixture is allowed to stand for 24 hours to allow heavy metals and suspended solids to precipitate. Finally, the treated wastewater is filtered through a sand filter.

[0049] (2) Rice husk treatment: Pour the pre-treated mining wastewater into the treatment tank, add rice husks, and soak them at 30°C for 12 hours to promote the degradation of organic matter in the rice husks. Then, air-dry them in a ventilation device at 30°C to reduce the moisture content in the rice husks to 10% with an air volume of 700m / s. 3 / h, thereby improving the gas permeability in the subsequent matrix preparation process;

[0050] (3) Preparation of substrate: Mix the treated rice husk with wood ash, cow dung, earthworms, bentonite and ligninase preparation, wherein the mixture of rice husk, wood ash, cow dung, earthworms, bentonite and ligninase preparation comprises 5% of the total mass of the raw materials by weight of the wood ash, 5% of the total mass of the ligninase preparation and the remainder of the mixture of treated rice husk, cow dung, earthworms and bentonite, wherein the mass ratio of rice husk, cow dung, earthworms and bentonite is 3:2:1:1, and the mixture is piled into a cone with a height and width of 1.5 m. The mixture is fermented at 50°C, pH 6.5 and a fermentation mixture humidity of 45% for 24 days, and the pile is turned over every 7 days during the fermentation process. After the fermentation is completed, a seedling medium is obtained.

[0051] Example 3

[0052] A method for preparing a seedling medium by treating rice husks with acidic mine wastewater:

[0053] (1) Pretreatment of acid mine drainage: limestone, sawdust and rice husk are mixed in a mass ratio of 1:1:1 and added to a sedimentation tank. The particle size of the limestone is 0.3 cm. Then the acid mine drainage is added to the sedimentation tank for neutralization and the pH is adjusted to 6.0. The volume ratio of the total amount of limestone, sawdust and rice husk to the acid mine drainage is 12:100. Then, polyaluminium chloride is added. The amount of polyaluminium chloride added to each liter of acid mine drainage is 150 mg. After stirring evenly, the mixture is allowed to stand for 20 hours to allow heavy metals and suspended solids to precipitate. Finally, the treated wastewater is filtered through a sand filter.

[0054] (2) Rice husk treatment: Pour the pre-treated mining wastewater into the treatment tank, add rice husks, and soak them at 25°C for 12 hours to promote the degradation of organic matter in the rice husks. Then, air-dry them in a ventilation device at 33°C to reduce the moisture content in the rice husks to 10%. The air volume is 800m 3 / h, thereby improving the gas permeability in the subsequent matrix preparation process;

[0055] (3) Preparation of substrate: Mix the treated rice husk with wood ash, cow dung, earthworms, bentonite and ligninase preparation, wherein the mixture of rice husk, wood ash, cow dung, earthworms, bentonite and ligninase preparation comprises 10% of the total mass of the raw materials by weight of the wood ash, 5% of the total mass of the ligninase preparation and the remainder of the mixture of treated rice husk, cow dung, earthworms and bentonite, wherein the mass ratio of rice husk, cow dung, earthworms and bentonite is 3:2:1:1, and the mixture is piled into a cone with a height and width of 2 m. The mixture is fermented at 55°C, pH 7.5 and a fermentation mixture humidity of 50% for 24 days, and the pile is turned over every 5 days during the fermentation process. After the fermentation is completed, a seedling substrate is obtained.

[0056] Comparative Example 1

[0057] Rice husks are mixed with wood ash, cow dung, earthworms, bentonite and lignin enzyme preparations, wherein the wood ash accounts for 10% of the total mass of the raw materials, the lignin enzyme preparation accounts for 10% of the total mass of the raw materials, the balance is a mixture of rice husks, cow dung, earthworms and bentonite, the mass ratio of rice husks, cow dung, earthworms and bentonite is 3:2:1:1, and the mixture is piled into a cone with a height and width of 2m. The mixture is fermented for 24 days at 55°C, pH 7.0 and a fermentation mixed humidity of 50%, and the pile is turned every 6 days during the fermentation process. After the fermentation is completed, a seedling medium is obtained.

[0058] Comparative Example 2

[0059] A conventional seedling medium for tobacco cultivation: peat soil, perlite and vermiculite are mixed in a ratio of 3:1:1, piled into a cone, the cone height and width are both 1.5m, fermented for 25 days at 55°C, pH 7.5, and fermentation mixed humidity of 55%, turned over every 5 days during the fermentation process, and a seedling medium is obtained after the fermentation is completed

[0060] Test Example 1 Tobacco Planting Experiment

[0061] Tobacco was planted simultaneously in two groups of fields, following the same planting and management practices, including watering, weeding, and pest and disease control.

[0062] 1.1 Observation indicators

[0063] The growth of the two groups of tobacco was observed regularly, including plant height, number of leaves, leaf area, occurrence of pests and diseases, etc. The yield and quality indicators of tobacco, including leaf weight, leaf thickness, chemical composition content, etc., were recorded at harvest.

[0064] 1.2 Data Analysis

[0065] The tobacco growth and yield data of the control group and the test group were compared to analyze the compost effect prepared by the method of the present invention and its influence on tobacco planting. The maturity of the compost is the result of the comprehensive effect of multiple indicators. The membership function value is used to evaluate the maturity of each treatment, and the key indicators such as temperature, total nitrogen, total phosphorus, total potassium, total nutrients of the compost, GI, etc. are comprehensively considered. The higher the membership function value, the higher the maturity. The maturity of the compost in the late stage is shown in Table 1.

[0066] Table 1 Membership function analysis of maturity

[0067] project temperature Organic matter TN TP TC Total nutrients GI Mean Comparative Example 1 0.40 0.40 0.42 0.42 0.45 0.42 0.42 0.42 Comparative Example 2 0.39 0.42 0.45 0.49 0.46 0.49 0.41 0.44 Example 1 0.45 0.65 0.53 0.51 0.65 0.59 0.56 0.56 Example 2 0.43 0.6 0.51 0.49 0.60 0.52 0.51 0.52 Example 3 0.43 0.62 0.53 0.5 0.63 0.55 0.54 0.54

[0068] Table 2 Comparison of heavy metal content in acid mine drainage before and after treatment

[0069]

[0070] As shown in the results of Table 2, the heavy metal content in the wastewater after treatment by the present invention is reduced and meets the first-level standard in the "Integrated Wastewater Discharge Standard" (GB 8978-1996).

[0071] Table 3 Changes in matrix pore size and organic matter content under different treatments

[0072]

[0073]

[0074] The results in Table 3 show that the porosity of the embodiment is the highest, the aeration is better after the material is treated, which is conducive to the development of the root system, and the highest water-holding porosity indicates that the matrix exhibits good water-holding performance after the treatment, which helps to retain moisture. The aeration porosity of comparative example 2 is the highest, but this example uses untreated wastewater to soak rice husks. Overall, the present invention has the best preparation effect on the matrix.

[0075] 1.3 Record the growth of the two groups of tobacco, including plant height, stem girth, number of leaves, leaf length, leaf width, etc. as shown in the following table.

[0076] Table 4 Agronomic traits of tobacco

[0077]

[0078] Through field tests, the tobacco growth conditions of the control group and the test group were compared in detail. The test results show that the emergence rate of the substrate seedling raising process prepared by the present invention is higher. The growth rate of tobacco prepared by the substrate of the present invention is significantly faster than that of the comparative example, and the plant height and the number of leaves are significantly increased. The leaf area and leaf thickness of the tobacco prepared by the substrate of the present invention are better than those of the comparative example, and the quality of the tobacco leaves is significantly improved. The yield and quality of the tobacco prepared by the substrate of the present invention are higher than those of the comparative example, and the chemical component content of the tobacco leaves is more balanced.

[0079] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing a seedling medium by treating rice husk with acidic mine wastewater, characterized in that: The following steps are involved: (1) Acid mine drainage pretreatment: limestone, wood chips and rice husks are mixed and added to a sedimentation tank, and then the acid mine drainage is added to the sedimentation tank for neutralization and pH adjustment, and then polyaluminium chloride is added, stirred evenly and allowed to stand to allow heavy metals and suspended matter to precipitate, and finally the treated wastewater is filtered through a sand filter; (2) Treating rice husks: Pour the pre-treated mining wastewater into a treatment tank, add rice husks, soak until the wastewater completely covers the rice husks to promote the degradation of organic matter in the rice husks, and then air-dry in a ventilation device to reduce the moisture content in the rice husks to 10-15%; (3) Preparation of substrate: Mix the treated rice husk with wood ash, cow dung, earthworms, bentonite and lignin enzyme preparation, pile them into a cone for fermentation, and obtain the seedling substrate after fermentation is completed.

2. A method for preparing a seedling medium by treating rice husks with acid mine wastewater according to claim 1, characterized in that: The mass ratio of limestone, sawdust and rice husk in step (1) is 1:1:1; The volume ratio of the total amount of the limestone, sawdust and rice husk to the acid mine drainage is 10-15:100; The amount of polyaluminium chloride added to each liter of acidic mine wastewater is 100-200 mg.

3. A method for preparing a seedling medium by treating rice husks with acid mine wastewater according to claim 1 or 2, characterized in that: During the neutralization in step (1), the pH is adjusted to 5.5-6.5; The standing time is 18-24h; The filter layer in the sand filter is quartz sand.

4. The method for preparing a seedling medium by treating rice husk with acid mine wastewater according to claim 1, characterized in that: In step (2), the soaking time is 12-18 hours and the soaking temperature is 25-35°C.

5. The method for preparing a seedling medium by treating rice husk with acid mine wastewater according to claim 1, characterized in that: In step (2), the air drying temperature is 30-35°C and the air volume is 600-800m 3 / h.

6. The method for preparing a seedling medium by treating rice husk with acid mine wastewater according to claim 1, characterized in that: In the mixture of the treated rice husk, wood ash, cow dung, earthworms, bentonite and ligninase preparation described in step (3), wood ash accounts for 5-10% of the total mass of the raw materials, the ligninase preparation accounts for 5-10% of the total mass of the raw materials, and the balance is a mixture of treated rice husk, cow dung, earthworms and bentonite.

7. A method for preparing a seedling medium by treating rice husks with acid mine wastewater according to claim 6, characterized in that: The mass ratio of the treated rice husk, cow dung, earthworm and bentonite in the mixture of treated rice husk, cow dung, earthworm and bentonite is 3:2:1:

1.

8. The method for preparing a seedling medium by treating rice husk with acid mine wastewater according to claim 1, characterized in that: The height and width of the fermentation cone in step (3) are both 1.5-2m; The fermentation temperature is 40-60°C, the fermentation time is 21-28 days, the fermentation pH is 6.5-7.5, and the fermentation mixed humidity is 45%-55%.

9. A method for preparing a seedling medium by treating rice husks with acid mine wastewater according to claim 8, characterized in that: During the fermentation process, the pile is turned over every 4-7 days.

10. Use of a seedling medium prepared by the method for preparing a seedling medium by treating rice husk with acid mine wastewater according to any one of claims 1 to 9 in tobacco seedling cultivation.

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