Soil improvement and remediation agent for comprehensive utilization of industrial and agricultural solid waste and microbial agent

Abstract

The application discloses a soil improvement and restoration agent for comprehensively utilizing industrial and agricultural solid wastes and microbial agents, and relates to the technical field of soil restoration.The soil improvement and restoration agent is composed of biochar-mushroom residue compost finished products, S microbial fertilizer and modified industrial solid wastes, and the mass ratio of the biochar-mushroom residue compost finished products, the S microbial fertilizer and the modified industrial solid wastes is 1:0.8:5.The biochar-mushroom residue compost finished products are obtained by blending and fermenting mushroom residue biochar and mushroom residue.The S microbial fertilizer is a composite microbial fertilizer mainly composed of bacillus subtilis and brevibacillus laterosporus.The modified industrial solid wastes are composed of steel slag, fly ash and titanium gypsum, which are all modified by citric acid.The soil improvement and restoration agent can effectively improve the physicochemical properties of the soil in a mining area and has a significant influence on plant growth, and the use amount of the microbial agents is greatly reduced, and the production cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of soil remediation technology, specifically to a soil amendment and remediation agent that comprehensively utilizes industrial and agricultural solid waste and microbial agents. Background Technology

[0002] In recent years, with the increasing demand for natural resources and the expansion of mining scale, the resulting large amounts of waste slag, waste rock, and tailings have not only occupied mining area land but also become major sources of pollution, posing a significant threat to the ecological environment of mining areas. Given that solid waste accumulated in open-pit mine spoil heaps not only occupies land but also easily induces debris flows and pollution from heavy metals and other harmful substances, solving the soil remediation problem of spoil heaps has become a key focus of ecological reconstruction in mining areas both domestically and internationally. Domestic mines have also intensified their research efforts on the ecological reconstruction of spoil heaps. Mine reclamation and ecological environment reconstruction are an inevitable trend in the development of the mining economy.

[0003] For ecological restoration of mining areas, we consider comprehensively applying methods and principles from soil science, microbiology, botany, soil and water conservation, materials science, environmental chemistry, and ecology. The spoil heap of the Panzhihua vanadium-titanium magnetite mine is representative of soils in similar mining areas; therefore, we use the spoil heap of the Panzhihua vanadium-titanium magnetite mine as our research area to provide practical and feasible technical solutions for soil improvement and management in similar mining reclamation areas. First, we analyze the physical, chemical, and biological properties of the soil. Second, we develop soil amendment materials suitable for the spoil heap of the Panzhihua vanadium-titanium magnetite mine, analyzing the process parameters and amendment mechanisms to construct a soil amendment system. Finally, we combine indoor simulation experiments and field trials to conduct a small-scale demonstration of vegetation restoration in the Panzhihua vanadium-titanium magnetite mine spoil heap, verifying the reclamation effect of the soil amendment materials. However, existing soil amendments are primarily microbial agents, which have limited effectiveness in improving the soil in the spoil heap of the Panzhihua vanadium-titanium magnetite mine and are also costly to produce, making large-scale application difficult. my country has abundant industrial and agricultural solid waste resources. If these resources can be formulated into soil conditioners suitable for mining areas, it will not only reduce the production cost of soil conditioners but also solve the problem of difficult disposal of industrial and agricultural solid waste. Summary of the Invention

[0004] To address the aforementioned problems in the prior art, this invention provides a soil conditioner and remediation agent that comprehensively utilizes industrial and agricultural solid waste and microbial agents, thereby solving the technical problems of poor improvement effect and high preparation cost of existing soil conditioners.

[0005] The technical solution adopted in this invention is as follows:

[0006] A soil conditioner and remediation agent that comprehensively utilizes industrial and agricultural solid waste and microbial agents is composed of biochar-mushroom residue compost, S-bacterial fertilizer, and modified industrial solid waste in a mass ratio of 1:0.8:5. The biochar-mushroom residue compost is obtained by co-fermentation of shiitake mushroom residue biochar and shiitake mushroom residue. The S-bacterial fertilizer is a compound microbial fertilizer mainly composed of Bacillus subtilis and Bacillus laterosporus. The modified industrial solid waste is composed of steel slag, fly ash, and titanium gypsum, all of which have been modified with citric acid.

[0007] Preferably, the preparation process of the mushroom residue biochar is as follows: the collected mushroom residue is washed, dried, crushed and placed in a sealed porcelain crucible, heated to 500°C in a muffle furnace and kept at that temperature for 3 hours. After cooling to room temperature, the black sample is taken out, ground and then the mushroom residue biochar is obtained.

[0008] Furthermore, the mass ratio of the mushroom residue biochar to the mushroom residue is 1:24.

[0009] Furthermore, the co-fermentation process of the mushroom residue biochar and mushroom residue is as follows: the collected mushroom residue is soaked in 4% NaOH solution for 24 hours, washed and filtered, the pH is adjusted to 7.20±0.25 with 10% dilute hydrochloric acid solution, EM stock solution is added for fermentation, the water content is controlled at 60%, the mushroom residue biochar is taken, stirred evenly, and placed in a 35℃ constant temperature water tank for cultivation, with a feed rate of 0.5L·min -1 Aeration is carried out at a certain rate, and biochar-microbial residue compost can be obtained after 60 days of fermentation.

[0010] Preferably, the modification process of the steel slag is as follows: the liquid-to-solid ratio of citric acid to steel slag is 2:1, the reaction is first shaken for 1 hour, then allowed to stand for 30 minutes, and then the mixture is stirred at 4000 r·min. -1 Centrifuge at a speed of 5 min, filter, wash until neutral, and finally dry at 65℃ to obtain modified steel slag. The concentration of citric acid is 0.5 mol·L⁻¹. -1 .

[0011] Furthermore, the modification process of the fly ash is as follows: the liquid-to-solid ratio of citric acid to fly ash is 2:1, the reaction is first shaken for 1 hour, then allowed to stand for 30 minutes, and then the mixture is reacted at 4000 r·min. -1 Centrifuge at a speed of 5 min, filter, wash until neutral, and finally dry at 65℃ to obtain modified fly ash. The concentration of citric acid is 0.75 mol·L⁻¹. -1 .

[0012] Furthermore, the modification process of the titanium gypsum is as follows: the liquid-to-solid ratio of citric acid to titanium gypsum is 2:1, the reaction is first shaken for 1 hour, then allowed to stand for 30 minutes, and then the mixture is reacted at 4000 r·min. -1Centrifuge at a speed of 5 min, filter, wash until neutral, and finally dry at 65℃ to obtain modified titanium gypsum. The concentration of citric acid is 1.0 mol·L⁻¹. -1 .

[0013] In summary, compared with the prior art, the present invention has the following advantages and beneficial effects:

[0014] This invention modifies industrial solid waste with a specific concentration of citric acid, and then produces a mixed biochar-microbial residue compost product with a specific biochar content, as well as S-microbial fertilizer. This effectively improves the physical and chemical properties of soil in mining areas and has a significant impact on plant growth, greatly reducing the amount of microbial agents used and lowering production costs. Attached Figure Description

[0015] Figure 1 Line graph showing the effect of biochar addition ratio on total nitrogen content in compost;

[0016] Figure 2 Line graph showing the effect of biochar addition ratio on humic acid content in compost.

[0017] Figure 3 Line graph showing the effect of biochar addition ratio on total phosphorus content in compost. Detailed Implementation

[0018] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and various embodiments. It should be understood that the specific embodiments described herein are only for explaining the invention and are not intended to limit the invention; that is, the described embodiments are merely some embodiments of the invention, and not all embodiments.

[0019] The test soils for the following embodiments of the present invention were taken from the spoil heap of the Zhujiabaobao mining area in Panzhihua City, Sichuan Province. The sampling point is located at 101°45′~101°46′E, 26°34′~26°35′N. Panzhihua has an average annual temperature of 19.7℃~20.5℃, abundant sunshine, strong solar radiation, an average of 2754 hours of sunshine per year, long summers with large daily temperature variations, indistinct seasons, low and concentrated rainfall, a frost-free period of over 300 days, and no winter in the river valleys. Extreme weather is rare in the region, making it the area with the richest sunshine resources in Sichuan Province. The main landform types include mountains, basins, hills, and river valley basins. There are as many as eleven soil types, including dry red soil, lateritic red soil, yellow-brown soil, and brown soil, among which red soil is the most widely distributed main natural soil in the region. The Panxi region is an important tectonic metallogenic belt in China.

[0020] Example 1

[0021] This embodiment mainly explores the effects of biochar-microbial residue compost prepared with different biochar ratios on soil. All experimental groups were kept consistent except for the biochar ratio. Details are as follows:

[0022] The shiitake mushroom residue comes from an organic fertilizer company, and the EM inoculant comes from Henan Yita Biotechnology Co., Ltd. (the main microbial strains are Bacillus and Actinomycetes).

[0023] Biochar preparation: The fungal residue material is taken from the collected fungal residue, washed, dried, crushed and placed in a sealed porcelain crucible, heated to 500℃ in a muffle furnace for 3 hours. After cooling to room temperature, the black sample is taken out, ground and passed through a 100-mesh sieve. The biochar products are collected and sealed in dry sealed bags.

[0024] Co-fermentation of mushroom residue and biochar: Take 125g of shiitake mushroom residue (dry weight), soak it in 4% NaOH solution for 24 hours, wash and filter it, adjust the pH to 7.20 (±0.25) with 10% dilute hydrochloric acid solution, add 1mL of EM stock solution for fermentation, control the water content at 60%, take 2%, 4%, 8%, and 12% of the dry weight of mushroom residue biochar respectively, stir evenly, place in a 35℃ constant temperature water tank for cultivation, and incubate at 0.5L·min -1 Aeration was carried out at a certain rate. Simultaneously, a single-stage fermentation of the microbial residue without biochar (CK) was established, while maintaining all other conditions identical.

[0025] First, the co-fermentation products of fungal residue and biochar were analyzed based on three factors: total nitrogen content, humic acid content, and total phosphorus content. The relevant test data are as follows: Figures 1-3 As shown, it is easy to see that, overall, a biochar addition of 4% is the optimal addition ratio.

[0026] The co-fermentation of microbial residue and biochar was added to the tested soil, and the relevant data in the soil are shown in Table 1. It is easy to see that the soil fertility parameters increased significantly after the addition of compost, indicating that the addition of biochar-compost has a good effect on improving soil properties. For relatively barren spoil heap soil, it can effectively improve the local soil properties. Moreover, the difference between 4% and 8% biochar addition is not significant. However, from a cost perspective, 4% addition is more suitable.

[0027] Table 1. Changes in soil properties after compost addition.

[0028]

[0029]

[0030] Example 2

[0031] This embodiment investigates the effect of citric acid on the modification of industrial solid waste mixtures. In each experimental group of this embodiment, the weight of the biochar-microbial residue compost product was 1% of the soil weight, the weight of the S-microbial fertilizer was 8‰ of the soil weight, and the weight of the industrial solid waste mixture was 5% of the soil weight. The S-microbial fertilizer provided in this embodiment is a commercially available compound microbial fertilizer mainly composed of Bacillus subtilis and Bacillus laterosporus.

[0032] 1. An investigation into the modification of steel slag in industrial solid waste mixtures (all other conditions are the same)

[0033] The steel slag used in the experiment was collected from Panzhihua, Sichuan Province, and produced by Panzhihua Iron and Steel Group Co., Ltd. After being dried, the slag was sealed in plastic bags and stored. Before the experiment, it was ground until it passed through a 100-mesh nylon sieve. The slag was tested at concentrations of 0, 0.5, 1, 1.5, and 2 mol·L⁻¹. -1 Citric acid was used to acidify steel slag. The reaction was carried out with 40 mL of citric acid and 20 g of steel slag at a liquid-to-solid ratio of 2:1, followed by homogenization and shaking for 1 hour, and then standing for 30 minutes. The mixture was then accelerated at 4000 rpm. -1 Centrifuge at a speed of 5 min, filter, wash until neutral, and dry at 65℃ for later use.

[0034] The modified steel slag was applied to the tested soil, and analysis of soil physicochemical properties and plant index data showed that citric acid-modified steel slag had a good modification effect on steel slag, lowering its pH value and increasing its Eh value. Applying modified steel slag to the soil affected soil pH, available potassium, available phosphorus, and total phosphorus, and also had a positive impact on various plant indicators such as germination rate and plant height. Based on the above results and comprehensive consideration, it can be concluded that 0.5 mol·L⁻¹ -1 Citric acid is the most effective modifier for steel slag.

[0035] 2. An investigation into the modification of fly ash in industrial solid waste mixtures (all other conditions are the same).

[0036] The fly ash used in the experiment was from Lingshou County Yucheng Mineral Products Processing Co., Ltd. The steel slag used in the experiment was dried and then sealed in plastic bags. Before use, it was ground to pass through a 100-mesh nylon sieve. The concentrations were 0, 0.5, 1, 1.5, and 2 mol·L⁻¹. -1 Citric acid was used to acid-modify steel fly ash slag. A liquid-to-solid ratio of 2:1 (40 mL citric acid and 20 g fly ash) was used, reacted, and the mixture was shaken for 1 hour and allowed to stand for 30 minutes. Then, the mixture was accelerated at 4000 rpm. -1 Centrifuge at a speed of 5 min, filter, wash until neutral, and dry at 65℃.

[0037] The modified fly ash was applied to the tested soil, and analysis of soil physicochemical properties and plant index data showed that citric acid had a good modifying effect on fly ash, lowering its pH value and increasing its Eh value. Applying modified fly ash to the soil affected soil pH, available potassium, available phosphorus, and total phosphorus, and also had a positive impact on various plant indicators such as germination rate and plant height. Based on the above results and comprehensive consideration, it can be concluded that 0.75 mol·L⁻¹ -1 Citric acid is the most effective modifier for fly ash.

[0038] 3. Investigation on the modification of titanium gypsum in industrial solid waste mixtures (all other conditions are the same)

[0039] The titanium gypsum used in the experiment was collected from Panzhihua, Sichuan Province, and produced by Panzhihua Iron and Steel Group Co., Ltd. After drying, the titanium gypsum was sealed and stored in a plastic bag. Before the experiment, it was ground until it passed through a 100-mesh nylon sieve. The titanium gypsum had a pH of 7.33, indicating a weakly alkaline material. The oxidation-reduction potential (Eh) was 235 mV. The titanium gypsum was acidified with 0, 0.5, 1, 1.5, and 2 mol / L citric acid. A liquid-to-solid ratio of 2:1 (40 mL citric acid with 20 g titanium gypsum) was reacted, homogenized, and shaken for 1 hour, then allowed to stand for 30 minutes. Afterward, it was centrifuged at 4000 r / min for 5 minutes, filtered, washed until neutral, and dried at 65℃.

[0040] The modified titanium gypsum was applied to the tested soil, and the soil physicochemical properties were analyzed. After modification with citric acid, the Eh value of the modified titanium gypsum remained essentially unchanged, but the pH value initially decreased, then increased, and remained stable. In particular, a low pH point appeared after modification with 1 mol / L citric acid, and analysis of plant index data showed that at 1.0 mol / L... -1 Citric acid-modified titanium plaster has a better effect.

[0041] 4. Investigate the influence of the proportions of each component in the modified industrial solid waste mixture.

[0042] The soil composition ratios for each experimental group are as follows: F1, F2, F3, F4, and F5 have mass ratios of titanium gypsum: steel slag: fly ash of 1:1:1, 1:1:3, 1:1:5, 1:1:7, and 1:1:9, respectively; T2, T3, T4, and T5 have mass ratios of fly ash: steel slag: titanium gypsum of 1:1:3, 1:1:5, 1:1:7, and 1:1:9, respectively; G2, G3, G4, and G5 have mass ratios of fly ash: titanium gypsum: steel slag of 1:1:3, 1:1:5, and 1:1:7, respectively. The effects of different composition ratios on the basic physicochemical properties of the soil are shown in Table 2, and the effects of different composition ratios on plant growth are shown in Table 3.

[0043] Table 2 Effects of different modified agent ratios on basic physical and chemical properties of soil

[0044]

[0045] As shown in Table 2, when the ratio of titanium gypsum to steel slag is constant, the indicators are better when the mass percentage of fly ash in the industrial solid waste mixture is 60% (1:1:3); when the ratio of fly ash to steel slag is constant, the indicators are better when the mass percentage of titanium gypsum in the industrial solid waste mixture is 77.8% (1:1:7); and when the ratio of fly ash to titanium gypsum is constant, the indicators are better when the mass percentage of steel slag in the industrial solid waste mixture is 77.8% (1:1:7).

[0046] Table 3 Effects of different modified formulation ratios on plant growth

[0047]

[0048] As shown in Table 3, the effects of different ratios on plant growth are slightly different from the effects of different ratios on the basic physical and chemical properties of soil. However, overall, G4 (titanium gypsum: steel slag: fly ash mass ratio of 1:7:1) has better comprehensive performance.

[0049] 5. Investigate the effects of not adding citric acid or citric acid not being modified beforehand (when using, citric acid is directly mixed with each component).

[0050] The proportions of each experimental group are as follows: F1, F2, F3, F4 and F5 have mass ratios of titanium gypsum: steel slag: fly ash of 1:1:1, 1:1:3, 1:1:5, 1:1:7 and 1:1:9, respectively; T2, T3, T4 and T5 have mass ratios of fly ash: steel slag: titanium gypsum of 1:1:3, 1:1:5, 1:1:7 and 1:1:9, respectively; G2, G3, G4 and G5 have mass ratios of fly ash: titanium gypsum: steel slag of 1:1:3, 1:1:5 and 1:1:7, respectively.

[0051] The effects of different unmodified formulations without citric acid on basic soil physicochemical properties and plant growth are shown in Tables 4 and 5, respectively. The effects of different formulations where citric acid is directly mixed with each component on basic soil physicochemical properties and plant growth are shown in Tables 6 and 7, respectively.

[0052] Table 4. Effects of different unmodified formulation ratios on basic physical and chemical properties of soil.

[0053]

[0054]

[0055] Table 5 Effects of different unmodified formulation ratios on plant growth

[0056]

[0057] Table 6. Effects of the proportion of unmodified agents on the basic physical and chemical properties of soil.

[0058]

[0059]

[0060] Table 7. Effects of the ratio of unmodified formulation on plant growth.

[0061]

[0062] Comparing the data in Tables 4-7 with those in Tables 2 and 3, it is easy to see that citric acid has a more significant effect on the overall impact of modifying the components in the industrial solid waste mixture in advance on the basic physicochemical properties of the soil and plant growth.

[0063] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

Claims

1. A soil conditioner and remediation agent that comprehensively utilizes industrial and agricultural solid waste and microbial agents, characterized in that, The product consists of biochar-mushroom residue compost (by mass ratio 1:0.8:5), S-bacterial fertilizer, and modified industrial solid waste. The biochar-mushroom residue compost is obtained by co-fermentation of shiitake mushroom residue biochar and shiitake mushroom residue, with a mass ratio of 1:

24. The S-bacterial fertilizer is a compound microbial fertilizer primarily composed of Bacillus subtilis and Bacillus laterosporus. The modified industrial solid waste consists of steel slag, fly ash, and titanium gypsum, all modified with citric acid, with a fly ash:titanium gypsum:steel slag mass ratio of 1:1:

7. The citric acid concentration during the steel slag modification process is 0.5 mol / L. L -1 The concentration of citric acid in the fly ash modification process is 0.75 mol. L -1 The concentration of citric acid in the modification process of the titanium gypsum is 1.0 mol. L -1 .

2. The soil conditioner and remediation agent based on the comprehensive utilization of industrial and agricultural solid waste and microbial agents as described in claim 1, characterized in that, The preparation process of the mushroom residue biochar is as follows: the collected mushroom residue is washed, dried, crushed and placed in a sealed porcelain crucible, heated to 500 ℃ in a muffle furnace and kept at that temperature for 3 hours. After cooling to room temperature, the black sample is taken out, ground and then the mushroom residue biochar is obtained.

3. The soil conditioner and remediation agent based on the comprehensive utilization of industrial and agricultural solid waste and microbial agents as described in claim 2, characterized in that, The co-fermentation process of mushroom spawn biochar and mushroom spawn residue is as follows: The collected mushroom spawn residue is soaked in 4% NaOH solution for 24 hours, washed and filtered, and the pH is adjusted to 7.20±0.25 with 10% dilute hydrochloric acid solution. EM stock solution is added for fermentation, controlling the moisture content at 60%. Mushroom spawn biochar is then taken, stirred evenly, and placed in a 35℃ constant temperature water bath for cultivation, with a feed rate of 0.5 L∙min⁻¹. -1 Aeration is carried out at a certain rate, and biochar-microbial residue compost can be obtained after 60 days of fermentation.

4. The soil conditioner and remediation agent based on the comprehensive utilization of industrial and agricultural solid waste and microbial agents as described in claim 1, characterized in that, The modification process of the steel slag is as follows: the liquid-to-solid ratio of citric acid to steel slag is 2:1, the reaction is first shaken for 1 hour, then allowed to stand for 30 minutes, and then the mixture is stirred at 4000 r. min -1 Centrifuge at a speed of 5 min, filter, wash until neutral, and finally dry at 65 ℃ to obtain modified steel slag.

5. The soil conditioner and remediation agent based on the comprehensive utilization of industrial and agricultural solid waste and microbial agents as described in claim 4, characterized in that, The modification process of the fly ash is as follows: the liquid-to-solid ratio of citric acid to fly ash is 2:1, the reaction is first shaken for 1 hour, then allowed to stand for 30 minutes, and then the mixture is stirred at 4000 r. min -1 Centrifuge at a speed of 5 min, filter, wash until neutral, and finally dry at 65 ℃ to obtain modified fly ash.

6. The soil conditioner and remediation agent based on the comprehensive utilization of industrial and agricultural solid waste and microbial agents as described in claim 5, characterized in that, The modification process of the titanium gypsum is as follows: the liquid-to-solid ratio of citric acid to titanium gypsum is 2:1, the reaction is first shaken for 1 hour, then allowed to stand for 30 minutes, and then the mixture is stirred at 4000 r. min -1 Centrifuge at a speed of 5 min, filter, wash until neutral, and finally dry at 65 ℃ to obtain modified titanium gypsum.

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