Organic solid waste resourceful treatment method for enhancing microbial compost activity

Abstract

The invention relates to the technical field of organic solid waste composting, in particular to an organic solid waste resourceful treatment method for enhancing microbial composting activity. A conventional microbial aerobic fermentation composting method is poor in composting efficiency. Aiming at the technical problem, the invention provides the organic solid waste resourceful treatment method for enhancing the microbial composting activity, the principle of synergistic effect of microorganisms and an electric field is adopted in the composting fermentation process, and a method for regulating the temperature and the ventilatory capacity in stages in the composting fermentation process is combined; the activity of microorganisms in the whole composting fermentation process is remarkably improved, and the composting quality and efficiency are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the technical field of organic solid waste composting, and particularly to a method for resource treatment of organic solid waste for enhancing the activity of microbial composting. Background Art

[0002] Organic solid waste mainly includes domestic waste, industrial waste (such as food processing waste residue, paper-making sludge, etc.) and agricultural waste (such as straw, livestock and poultry manure, etc.). Its high organic matter content (usually more than 60% of the dry weight) determines its resource potential, but improper disposal is likely to cause problems such as soil pollution, water eutrophication and greenhouse gas emissions.

[0003] Currently, the mainstream treatment methods include:

[0004] Composting method: converting organic matter into humus fertilizer through aerobic fermentation of microorganisms. However, the traditional composting cycle is long (30 - 60 days), and the high-temperature stage (55 - 70 °C) is likely to cause the inactivation of functional microorganisms, reducing the degradation efficiency.

[0005] Biological treatment method: relying on specific microorganisms (such as cellulose-decomposing bacteria, lignin-degrading bacteria) to decompose complex organic matter. However, a single strain is difficult to adapt to multi-component waste, and it is easily affected by environmental fluctuations during industrial-scale application.

[0006] Incineration method: rapidly reducing the amount through high-temperature oxidation, but it has high energy consumption and produces harmful gases such as dioxins and NOx, which does not meet the requirements of green and low-carbon.

[0007] Composting is regarded as the core technology for organic solid waste treatment due to its environmental friendliness and resource value. However, its efficiency and product quality highly depend on the functional stability of the microbial community. Traditional composting relies on the natural succession of indigenous microorganisms and has the following defects:

[0008] High-temperature inhibition effect: During the traditional composting process, the temperature is high, the microbial community structure is unstable, and the activity difference is large. The high-temperature period (>60 °C) of composting lasts for several days, and the activity of most mesophilic bacteria (optimum temperature 25 - 45 °C) is inhibited. Only heat-resistant bacteria (such as Bacillus) survive briefly, resulting in incomplete decomposition of refractory organic matter such as lignocellulose. Summary of the Invention

[0009] The problem existing in the prior art is that the composting efficiency of the conventional method of aerobic fermentation of microorganisms is poor. In view of the above technical problems, the present invention provides a compound microbial inoculant, which is obtained by performing 6 - 8 wet-dry cycles on the initial compound inoculant, and the time for one wet-dry cycle is 24 h;

[0010] The one wet-dry cycle treatment includes the following steps:

[0011] At room temperature, soak the initial composite bacterium agent in the trace element solution for 13 - 16 h, then dry it at 65 - 75 °C for 7 - 8 h, and then cool it at 15 - 20 °C;

[0012] The initial composite bacterium agent includes a biochar carrier and biological bacteria attached to the biochar carrier;

[0013] The trace element solution is a homogeneous mixed solution formed by zinc chloride, copper chloride, sodium titanate and water;

[0014] The biological bacteria include thermophilic bacteria, Bacillus and Aspergillus.

[0015] Preferably, the preparation method of the initial composite bacterium agent includes the following steps:

[0016] (1) Perform plasma jet treatment on the biochar carrier. The gas for the plasma jet treatment is a gas mixture composed of oxygen and helium in a volume ratio of 0.05 - 0.15:1, the power of the power supply is 150 - 250 W, and the treatment duration is 1 - 2 min;

[0017] (2) Mix the thermophilic bacteria solution, Bacillus solution and Aspergillus solution with an effective viable count of 0.8×10 9 ~1×10 9 CFU / mL evenly according to a volume ratio of 1 - 2:1:1 to obtain a microbial bacteria solution;

[0018] (3) Mix the biochar carrier after plasma jet treatment and the microbial bacteria solution evenly according to a dosage ratio of 0.7 - 0.9 g:1 mL, and then naturally dry it at room temperature to obtain the initial composite bacterium agent.

[0019] Preferably, the preparation method of the biochar carrier includes the following steps:

[0020] (1) Pyrolyze the biochar raw material at 700 - 750 °C under nitrogen protection for 11 - 13 h, then pass it through a 50 - 80 mesh sieve to obtain biochar powder. Soak the biochar powder in a sulfuric acid aqueous solution with a mass concentration of 5 - 6% for 15 - 18 h, and dry the biochar powder after the soaking treatment;

[0021] (2) Uniformly mix the biochar powder dried in step (1) with an aqueous dopamine solution with a mass concentration of 1 - 2 g / L, an aqueous sodium hydroxide solution with a mass concentration of 5 - 6%, and silica white according to a mass ratio of 0.8 - 1:0.5:4:0.4. Then heat the reaction system to 120 - 130 °C, stir the reaction at a constant temperature for 25 - 35 min, and then cool the mixture to room temperature. The obtained mixture is subjected to solid - liquid separation, washed and dried to obtain a mixture, and an initial carrier is obtained;

[0022] (3) Under nitrogen protection, the initial carrier is subjected to low-temperature heat treatment at a temperature of 190 - 240 °C for a treatment time of 2.5 - 4 h, and then naturally cooled to room temperature to obtain a biochar carrier.

[0023] Preferably, the biochar raw material includes one or more combinations of crop straws, red pine nut shells, or bamboo.

[0024] Preferably, the trace elements in the trace element solution are composed of zinc chloride, copper chloride, and sodium titanate in a mass ratio of 1 - 2:0.4 - 0.6:0.2 - 0.5, and the total mass concentration of the trace elements in the trace element solution is 1 - 5 g / L.

[0025] Preferably, the thermophilic bacterium is Bacillus thiaminolyticus thermophilus.

[0026] Preferably, the Bacillus is Bacillus subtilis.

[0027] Preferably, the Aspergillus is Aspergillus niger.

[0028] An organic solid waste resource treatment method using electric field enhancement, which comprises the following steps:

[0029] S1. Pretreatment of organic solid waste:

[0030] The organic solid waste is crushed and mixed with water to obtain a compost, the water content of the compost is 55 - 65%, the C / N value is 22 - 28, and the pH of the compost is adjusted to 6 - 7.

[0031] S2. Aerobic composting in stages (during the whole process of step S2, the compost is turned over every 4 days):

[0032] (1) Heating stage:

[0033] Add the above-mentioned composite microbial inoculant accounting for 7 - 10 wt% of the mass of the compost obtained in step S1 to start composting. The compost rises from room temperature to 80 ± 5 °C. During the heating process, every time the temperature rises by 10 - 15 °C, the compost is aerated once, and the aeration volume each time is 0.5 - 1 L / (min·kg). When the C / N value of the compost drops by 50 - 60%, every time the temperature rises by 4 - 6 °C, the compost is aerated once, and the aeration volume each time is 1.2 - 1.5 L / (min·kg).

[0034] (2) Ultra-high temperature stage:

[0035] After the heating is completed, the temperature is kept at 5-7 days. During the heating, the compost is ventilated once every 2-4 hours, and the ventilation volume each time is 0.1-0.2L / (min·kg). When the C / N value of the compost continues to decrease by 30-40% of the C / N value of the compost after the heating is completed, an electric field is applied to the compost, and the voltage is 5-10V;

[0036] (3) Cooling stage:

[0037] After step (2) is completed, a composite microbial agent accounting for 2-3 wt% of the compost is added to the compost, and after the compost is turned evenly, the compost is naturally cooled to 25-35°C. During the cooling process, the compost is ventilated once every 5-10°C, and the ventilation volume each time is 1.2-1.5 L / (min·kg);

[0038] (4) Low temperature stage:

[0039] After the cooling in step (3) is completed, the compost is kept warm for 4-5 days. During the warming process, an electric field is continuously applied to the compost, and the compost is ventilated once every 2-4 hours. The ventilation volume each time is 0.1-0.2L / (min·kg) and the voltage is 5-10V.

[0040] Preferably, the pH adjuster comprises hydrochloric acid or sodium hydroxide aqueous solution.

[0041] The present invention has the following beneficial effects:

[0042] (1) The present invention divides composting into four stages. A composite microbial agent is added during the temperature rise process to introduce a variety of beneficial microorganisms. These microorganisms can quickly start the process of decomposing organic matter in the early stage of composting. The ventilation volume is adjusted according to the changes in temperature and C / N value. This ventilation strategy can well meet the oxygen requirements of microorganisms at different decomposition stages. In the initial stage, sufficient oxygen can be provided to the microorganisms so that they can decompose easily decomposable organic matter in a suitable oxygen environment.

[0043] Generate heat to promote compost heating. When the C / N value decreases, adjust ventilation. This is because as the easily decomposable organic matter decreases, the demand for oxygen by microorganisms will change. At this time, increasing ventilation can ensure that microorganisms continue to efficiently decompose the remaining organic matter and accelerate the heating process. In the ultra-high temperature stage, pathogens in organic solid waste can be effectively killed, which can improve the safety and quality of composting. Ventilation and electric field synergistic treatment can maintain a certain activity of microorganisms in the ultra-high temperature stage, allowing them to continue to decompose organic matter. In the cooling stage, adding composite microbial agents again can supplement microorganisms and stabilize the quality of compost. In the low temperature stage after the cooling is completed, ventilation and electric fields can further promote the decomposition and transformation of organic matter.

[0044] (2) The composite microbial inoculant prepared by the present invention uses biochar treated by a plasma jet as a carrier, providing a better attachment environment for microorganisms. The microorganisms can adhere more firmly to the pores and functional groups on the surface of the biochar, maintaining high activity. Thermophilic bacteria, Bacillus, and Aspergillus can cooperate to rapidly decompose easily decomposable organic matter in a high-temperature environment, and can decompose various components in organic solid waste more comprehensively, improving the quality and efficiency of composting.

[0045] (3) The composite microbial inoculant after multiple wet-dry cycle treatments can better adapt to the complex environmental changes during composting, maintain high activity at all stages of composting, and decompose organic solid waste more effectively, thereby further improving the composting efficiency. Brief Description of the Drawings

[0046] Figure 1 : The test results of the total nitrogen retention rate of the composts obtained in Examples 1-13 and Control Examples 1-2 are as shown in the attached Figure 1 description.

[0047] Figure 2 : The removal rates of organic pollutants in the organic solid waste in Examples 1-13 and Control Examples 1-2 are as shown in the attached Figure 2 description.

[0048] Figure 3 : The test results of the total nitrogen retention rate of the composts obtained in Example 1, Examples 14-19, and Control Example 3 are as shown in the attached Figure 3 description.

[0049] Figure 4 : The removal rates of organic pollutants in the organic solid waste in Example 1, Examples 14-19, and Control Example 3 are as shown in the attached Figure 4 description.

[0050] Figure 5 : The test results of the total nitrogen retention rate of the composts obtained in Example 1, Examples 20-29, and Control Examples 4-5 are as shown in the attached Figure 5 description.

[0051] Figure 6 : The removal rates of organic pollutants in the organic solid waste in Example 1, Examples 20-29, and Control Examples 4-5 are as shown in the attached Figure 6 description.

[0052] Figure 7 : Schematic diagram of the device structure for the electric field and aeration during the composting fermentation process of Example 1. Detailed Embodiments

[0053] The present invention will be described in detail below in conjunction with embodiments. However, it should be understood that the following embodiments are only illustrative examples of the implementation modes of the present invention, rather than limiting the scope of the present invention.

[0054] The sources of the following raw materials used in the following embodiments of the present invention are described as follows:

[0055] The thermophilic bacterium is Bacillus thermoaerophilus thiaminolyticus (CGMCC No. 17867), purchased externally, supplier: China General Microbiological Culture Collection Center.

[0056] The bacillus is Bacillus subtilis (CMCC(B)63501), purchased externally, supplier: China National Center for Medical Culture Collections.

[0057] The aspergillus is Aspergillus niger (CMCC(F)98003), purchased externally, supplier: China National Center for Medical Culture Collections.

[0058] The pH regulator used in the following embodiments of the present invention can be 0.5 M hydrochloric acid or an aqueous sodium hydroxide solution with a mass concentration of 25%.

[0059] The preparation methods of different bacterial solutions in the following embodiments of the present invention are as follows:

[0060] The preparation method of the thermophilic bacterium solution is as follows:

[0061] Pick a small amount of thermophilic bacterium cells and inoculate them into CDM medium to obtain a seed solution, and then inoculate the seed solution into LB liquid medium. At 25 - 30 °C, with an initial pH value of 7 - 7.5, stir and culture to obtain a thermophilic bacterium solution with an effective viable cell count of 0.8×10 9 ~1×10 9 CFU / mL.

[0062] The preparation method of the bacillus solution is as follows:

[0063] Pick a small amount of bacillus cells and inoculate them into broth agar medium to obtain a seed solution, and then inoculate the seed solution into LB liquid medium. At 25 - 30 °C, with an initial pH value of 7 - 7.5, stir and culture to obtain a bacillus solution with an effective viable cell count of 0.8×10 9 ~1×10 9 CFU / mL.

[0064] The preparation method of the aspergillus solution is as follows:

[0065] Pick a small amount of aspergillus cells and inoculate them into potato dextrose agar medium to obtain a seed solution, and then inoculate the seed solution into LB liquid medium. At 25 - 30 °C, with an initial pH value of 7 - 7.5, stir and culture to obtain an aspergillus solution with an effective viable cell count of 0.8×109 -1×10 9 CFU / mL Aspergillus fungus liquid.

[0066] The aeration mentioned in the following embodiments of the present invention refers to introducing air into the compost.

[0067] The schematic diagram of the device structure used for the electric field and aeration during the compost fermentation process in the following Embodiment 1 of the present invention is as shown in the attached Figure 7 description. In the figure, the fertilizer is placed in a square container with an open top. A positive electrode plate and a negative electrode plate are respectively arranged on the left and right sides of the container. The parallel spacing between the positive electrode plate and the negative electrode plate is 80 cm. The aeration device is a blower, and the air outlet of the blower is communicated with the bottom of the square container. The positive electrode plate and the negative electrode plate are respectively connected to the positive and negative electrodes of an external power supply through wires.

[0068] Embodiment 1

[0069] A method for enhancing the resource treatment of organic solid waste by using an electric field, the steps are as follows:

[0070] S1. Pretreatment of organic solid waste:

[0071] The chicken manure is pulverized and mixed with water to obtain a compost. The water content of the compost is 60%, the C / N value is 26, and the pH of the compost is adjusted to 6.5.

[0072] S2. Aerobic composting in stages:

[0073] (1) Heating stage:

[0074] Add a composite microbial inoculant accounting for 8.5 wt% of the mass of the compost obtained in step S1, and start composting. The compost rises from room temperature to 80°C. During the heating process, every time the temperature rises by 13°C, the compost is aerated once, and the aeration volume each time is 0.8 L / (min·kg). When the C / N value of the compost drops by 55%, every time the temperature rises by 5°C, the compost is aerated once, and the aeration volume each time is 1.3 L / (min·kg).

[0075] (2) Ultra-high temperature stage:

[0076] After the heating in step (1) ends, keep warm for 6 d. During the heat preservation process, aerate the compost once every 3 h, and the aeration volume each time is 0.15 L / (min·kg). When the C / N value of the compost continues to drop by 35% of the C / N value of the compost after the heating ends, start applying an electric field to the compost, and the voltage magnitude is 8 V.

[0077] (3) Cooling stage:

[0078] After step (2) ends, add a compound microbial inoculant accounting for 2.5 wt% of the compost to the compost. After turning the pile evenly, let it cool naturally to 30 °C. During the cooling process, ventilate the compost once every time the temperature drops by 8 °C, and the ventilation volume each time is 1.4 L / (min·kg);

[0079] (4) Low-temperature stage:

[0080] After the cooling in step (3) ends, keep warm for 4.5 d. During the heat preservation process, continuously apply an electric field to the compost, and ventilate the compost once every 3 h. The ventilation volume each time is 0.15 L / (min·kg), and the voltage magnitude is 8 V;

[0081] During the whole process of step S2, turn the pile once every 4 d.

[0082] The preparation method of the above compound microbial inoculant is as follows:

[0083] Perform wet-dry cycling treatment on the initial compound inoculant 7 times to obtain the compound microbial inoculant. The time for one wet-dry cycling treatment is 24 h;

[0084] The steps of the one wet-dry cycling treatment are as follows:

[0085] At room temperature, soak the initial compound inoculant in the trace element solution for 14.5 h, then dry it at 70 °C for 7.5 h, and then cool it at 18 °C; the trace element solution is a mixed solution formed by zinc chloride, copper chloride, sodium titanate and water. The trace elements in the trace element solution are composed of zinc chloride, copper chloride, and sodium titanate according to a mass ratio of 1.5:0.5:0.3, and the total mass concentration of the trace elements in the trace element solution is 3 g / L.

[0086] The preparation method of the initial compound inoculant is as follows:

[0087] (1) Perform plasma jet treatment on the biochar carrier. The gas for the plasma jet treatment is a gas mixture of oxygen and helium in a volume ratio of 0.1:1, the power of the power supply is 200 W, and the treatment duration is 1.5 min;

[0088] (2) Mix the thermophilic bacteria liquid, bacillus liquid and aspergillus liquid with an effective viable count of 0.9×10 9 CFU / mL evenly according to a volume ratio of 1.5:1:1 to obtain the microbial liquid;

[0089] (3) Mix the biochar carrier after plasma jet treatment and the microbial liquid evenly according to a dosage ratio of 0.8 g:1 mL, and then let it dry naturally at room temperature to obtain the initial compound inoculant.

[0090] The preparation method of the biochar carrier is as follows:

[0091] (1) The biochar raw material (corn straw) is pyrolyzed at 725 °C under nitrogen protection for 12 h, and then passed through a 70-mesh sieve to obtain biochar powder. The biochar powder is soaked in a sulfuric acid aqueous solution with a mass concentration of 5.5% for 17.5 h, and after the soaking treatment is completed, the biochar powder is dried;

[0092] (2) The dried biochar powder in step (1) is uniformly mixed with an aqueous dopamine solution with a mass concentration of 1.5 g / L, an aqueous sodium hydroxide solution with a mass concentration of 5.5%, and silica white in a mass ratio of 0.9:0.5:4:0.4. Then, the reaction system is heated to 125 °C and stirred at a constant temperature for 30 min to obtain a mixture. The mixture is then naturally cooled to room temperature. After the obtained mixture is centrifuged, washed three times with water and dried, an initial carrier is obtained;

[0093] (3) Under nitrogen protection, the initial carrier is subjected to low-temperature heat treatment at a temperature of 215 °C for 3 h, and then naturally cooled to room temperature to obtain a biochar carrier.

[0094] Example 2 is the same as Example 1, except that: in step S1 of Example 2, the water content of the compost is 55%, the pH is 6, and the C / N value is 22.

[0095] Example 3 is the same as Example 1, except that: in step S1 of Example 3, the water content of the compost is 65%, the pH is 7, and the C / N value is 28.

[0096] Example 4 is the same as Example 1, except that: in Example 4, the composite microbial inoculant added in the heating stage of step S2 accounts for 7 wt% of the total mass of the compost, and the composite microbial inoculant added in the cooling stage of step S2 accounts for 3 wt% of the total mass of the compost.

[0097] Example 5 is the same as Example 1, except that: in Example 5, the composite microbial inoculant added in the heating stage of step S2 accounts for 10 wt% of the total mass of the compost, and the composite microbial inoculant added in the cooling stage of step S2 accounts for 2 wt% of the total mass of the compost.

[0098] Example 6 is the same as Example 1, except that: in the heating stage of step S2 of Example 6, the compost is aerated once every 10 °C increase in temperature, and the aeration volume each time is 0.5 L / (min·kg). When the C / N value of the compost drops by 55%, the compost is aerated once every 4 °C increase in temperature, and the aeration volume each time is 1.2 L / (min·kg).

[0099] Example 7 is the same as Example 1, except that: in the heating-up stage of step S2 in Example 7, every time the temperature is increased by 15°C, the compost is aerated once, and the aeration volume each time is 1 L / (min·kg). When the C / N value of the compost has decreased by 60%, every time the temperature is increased by 6°C, the compost is aerated once, and the aeration volume each time is 1.5 L / (min·kg).

[0100] Example 8 is the same as Example 1, except that: in Example 8, in the ultra-high temperature stage of step S2, it is kept warm for 5 d. During the heat preservation process, every 2 h, the compost is aerated once, and the aeration volume each time is 0.1 L / (min·kg). When the C / N value of the compost continues to decrease by 30% of the C / N value of the compost after the heating ends, an electric field is applied to the compost, and the voltage magnitude is 10 V.

[0101] Example 9 is the same as Example 1, except that: in Example 9, in the ultra-high temperature stage of step S2, it is kept warm for 7 d. During the heat preservation process, every 4 h, the compost is aerated once, and the aeration volume each time is 0.2 L / (min·kg). When the C / N value of the compost continues to decrease by 40% of the C / N value of the compost after the heating ends, an electric field is applied to the compost, and the voltage magnitude is 5 V.

[0102] Example 10 is the same as Example 1, except that: in the cooling stage of step S2 in Example 10, during the cooling process, every time the temperature is decreased by 5°C, the compost is aerated once, and the aeration volume each time is 1.2 L / (min·kg).

[0103] Example 11 is the same as Example 1, except that: in the cooling stage of step S2 in Example 11, during the cooling process, every time the temperature is decreased by 10°C, the compost is aerated once, and the aeration volume each time is 1.5 L / (min·kg).

[0104] Example 12 is the same as Example 1, except that: in the low temperature stage of step S2 in Example 12, it is kept warm for 4 d. During the heat preservation process, an electric field is continuously applied to the compost, and every 2 h, the compost is aerated once, and the aeration volume each time is 0.1 L / (min·kg), and the voltage magnitude is 5 V.

[0105] Example 13 is the same as Example 1, except that: in the low temperature stage of step S2 in Example 13, it is kept warm for 5 d. During the heat preservation process, an electric field is continuously applied to the compost, and every 4 h, the compost is aerated once, and the aeration volume each time is 0.2 L / (min·kg), and the voltage magnitude is 10 V.

[0106] Example 14 is the same as Example 1, except that: in step (1) of the preparation process of the biochar carrier in Example 14, the biochar raw material (corn straw) is pyrolyzed at 700 °C under nitrogen protection for 11 h, and then passed through a 50-mesh sieve to obtain biochar powder, and the biochar powder is soaked in a sulfuric acid aqueous solution with a mass concentration of 5% for 15 h.

[0107] Example 15 is the same as Example 1, except that: in step (1) of the preparation process of the biochar carrier in Example 15, the biochar raw material (corn straw) is pyrolyzed at 750 °C under nitrogen protection for 13 h, and then passed through an 80-mesh sieve to obtain biochar powder, and the biochar powder is soaked in a sulfuric acid aqueous solution with a mass concentration of 6% for 18 h.

[0108] Example 16 is the same as Example 1, except that: step (2) in the preparation process of the biochar carrier in Example 16

[0109] is to uniformly mix the biochar powder after drying treatment in step (1) with an aqueous dopamine solution with a mass concentration of 1 g / L, an aqueous sodium hydroxide solution with a mass concentration of 5%, and silica white in a mass ratio of 0.8:0.5:4:0.4, and then heat the reaction system to 120 °C, stir the reaction at a constant temperature for 25 min to obtain a mixture, and then naturally cool the mixture to room temperature. After the obtained mixture is centrifuged, washed three times with water and dried, an initial carrier is obtained.

[0110] Example 17 is the same as Example 1, except that: step (2) in the preparation process of the biochar carrier in Example 17

[0111] is to uniformly mix the biochar powder after drying treatment in step (1) with an aqueous dopamine solution with a mass concentration of 2 g / L, an aqueous sodium hydroxide solution with a mass concentration of 6%, and silica white in a mass ratio of 1:0.5:4:0.4, and then heat the reaction system to 130 °C, stir the reaction at a constant temperature for 35 min to obtain a mixture, and then naturally cool the mixture to room temperature. After the obtained mixture is centrifuged, washed three times with water and dried, an initial carrier is obtained.

[0112] Example 18 is the same as Example 1, except that: in step (3) of the preparation process of the biochar carrier in Example 18, the initial carrier is subjected to low-temperature heat treatment under nitrogen protection at a temperature of 190 °C for 2.5 h, and then naturally cooled to room temperature to obtain a biochar carrier.

[0113] Example 19 is the same as Example 1, except that: in step (3) of the preparation process of the biochar carrier in Example 19, the initial carrier is subjected to low-temperature heat treatment under nitrogen protection at a temperature of 240 °C for 4 h, and then naturally cooled to room temperature to obtain a biochar carrier.

[0114] Example 20 is the same as Example 1, except that: in step (1) of the preparation process of the initial composite bacterial agent in Example 20, the biochar carrier is treated by plasma jet, and the gas for the plasma jet treatment is a gas mixture composed of oxygen and helium in a volume ratio of 0.05:1, the power of the power supply is 150 W, and the treatment duration is 1 min.

[0115] Example 21 is the same as Example 1, except that: in step (1) of the preparation process of the initial composite bacterial agent in Example 21, the biochar carrier is treated by plasma jet, and the gas for the plasma jet treatment is a gas mixture composed of oxygen and helium in a volume ratio of 0.15:1, the power of the power supply is 250 W, and the treatment duration is 2 min.

[0116] Example 22 is the same as Example 1, except that: in the preparation process of the initial composite bacterial agent in Example 22, in step (2), the thermophilic bacterial liquid, the bacillus bacterial liquid, and the aspergillus bacterial liquid with an effective viable count of 0.8×10 9 CFU / mL are mixed evenly in a volume ratio of 1:1:1 to obtain a microbial bacterial liquid;

[0117] In step (3), the biochar carrier after plasma jet treatment is mixed evenly with the microbial bacterial liquid in a dosage ratio of 0.7 g:1 mL, and then naturally dried at room temperature to obtain the initial composite bacterial agent.

[0118] Example 23 is the same as Example 1, except that: in the preparation process of the initial composite bacterial agent in Example 23, in step (2), the thermophilic bacterial liquid, the bacillus bacterial liquid, and the aspergillus bacterial liquid with an effective viable count of 1×10 9 CFU / mL are mixed evenly in a volume ratio of 2:1:1 to obtain a microbial bacterial liquid;

[0119] In step (3), the biochar carrier after plasma jet treatment is mixed evenly with the microbial bacterial liquid in a dosage ratio of 0.9 g:1 mL, and then naturally dried at room temperature to obtain the initial composite bacterial agent.

[0120] Example 24 is the same as Example 1, except that: in the preparation process of the composite microbial bacterial agent in Example 24,

[0121] The initial composite bacterial agent is subjected to 6 wet-dry cycles, and the period of one wet-dry cycle is 24 h. The steps of one wet-dry cycle treatment are as follows: at room temperature, the initial composite bacterial agent is soaked in the trace element solution for 13 h, then dried at 65 °C for 7 h, and then cooled at 15 °C.

[0122] Example 25 is the same as Example 1, except that: in the preparation process of the composite microbial bacterial agent in Example 25,

[0123] The initial composite bacterial agent was subjected to dry-wet cycle treatment for 8 times, and the period of one dry-wet cycle was 24 hours. The steps of one dry-wet cycle treatment were as follows: at room temperature, the initial composite bacterial agent was soaked in the trace element solution for 16 hours, then dried at 75°C for 8 hours, and then cooled at 20°C.

[0124] Example 26 is the same as Example 1, except that the trace element solution in Example 26 is a mixed solution of zinc chloride, copper chloride, sodium titanate and water, the trace elements in the trace element solution are composed of zinc chloride, copper chloride and sodium titanate in a mass ratio of 1:0.6:0.5, and the total mass concentration of the trace elements in the trace element solution is 1 g / L.

[0125] Example 27 is the same as Example 1, except that the trace element solution in Example 27 is a mixed solution of zinc chloride, copper chloride, sodium titanate and water, the trace elements in the trace element solution are composed of zinc chloride, copper chloride and sodium titanate in a mass ratio of 2:0.4:0.2, and the total mass concentration of the trace elements in the trace element solution is 5 g / L.

[0126] Example 28 is the same as Example 1, except that in step S2 of Example 28, the pile is turned over every 3 days.

[0127] Example 29 is the same as Example 1, except that in step S2 of Example 29, the pile is turned every 5 days.

[0128] Control Example 1 is the same as Example 1, except that the ventilation rate during the entire composting process of Control Example 1 is 0.8 L / (min·kg).

[0129] Control Example 2 is the same as Example 1, except that the composite microbial agent in Control Example 2 is added at one time during the temperature rising stage of step S2.

[0130] Control Example 3 is the same as Example 1, except that the biochar powder in the preparation process of the biochar carrier in Control Example 3 is not soaked in a sulfuric acid aqueous solution.

[0131] The difference between Control Example 4 and Example 1 is that the biochar carrier is not subjected to plasma jet treatment during the initial preparation of the composite bacterial agent in Control Example 4.

[0132] The difference between Control Example 5 and Example 1 is that, during the preparation process of the composite microbial agent in Control Example 5, the initial composite microbial agent was not subjected to dry-wet cycle treatment.

[0133] 1. To explore the factors affecting the total nitrogen retention rate in the composting process and the removal rate of organic pollutants in organic solid waste.

[0134] Instructions attached Figure 1 and2 They are respectively the test results of the total nitrogen retention rate and the test results of the removal rate of organic pollutants of the composts obtained in Examples 1-13 and Comparative Examples 1-2. The test results show that in Comparative Example 1, due to the lack of the step of adjusting the ventilation volume according to the temperature state and C / N value state, and in Comparative Example 2, due to the lack of the step of adding the composite microbial inoculant in stages, the total nitrogen retention rate and the removal rate of organic pollutants are significantly decreased compared with those in Examples 1-13. Thus, it can be seen that adjusting the ventilation volume and the addition amount of the composite microbial inoculant at different stages of compost fermentation can effectively improve the composting efficiency;

[0135] Comparing Examples 1-13, if the C / N value of the compost is too small or too large, the addition amount of the composite microbial inoculant in two successive times is too small or too large, the change of the ventilation volume during the temperature rising period is too small or too large, the application degree of the electric field in the ultra-high temperature stage of compost fermentation is too small or too large, the ventilation volume in the cooling stage of compost fermentation is too small or too large, and the application degree of the electric field in the low temperature stage of compost fermentation is too small or too large, the total nitrogen retention rate and the removal rate of organic pollutants of the compost will be reduced. Through comprehensive comparison, it can be known that the composting effect of Example 1 is better.

[0136] 2. Explore the influence of the preparation method of the biochar carrier on the total nitrogen retention rate of the obtained compost and the removal rate of organic pollutants in the organic solid waste.

[0137] Specification appendix Figure 3 and specification appendix Figure 4 They are respectively the test results of the total nitrogen retention rate of the composts obtained in Example 1, Examples 14-19 and Comparative Example 3 and the test results of the removal rate of organic pollutants. The test results show that the total nitrogen retention rate and the removal rate of organic pollutants of Comparative Example 3 are significantly decreased compared with those in Example 1, Examples 14-19;

[0138] Comparing Example 1, Examples 14-19, it can be known that the soaking time of the biochar in the sulfuric acid aqueous solution and the concentration of the sulfuric acid aqueous solution, the mass ratio of the biochar to the dopamine solution being too small or too large, and the conditions of the low-temperature heat treatment of the initial carrier will all reduce the total nitrogen retention rate and the removal rate of organic pollutants. Generally speaking, through comprehensive comparison, the composting effect of Example 1 is better.

[0139] 3. Explore the influence of the preparation method of the composite microbial inoculant on the total nitrogen retention rate in the obtained compost and the removal rate of organic pollutants in the organic solid waste.

[0140] Specification appendix Figure 5 and specification appendix Figure 6 They are respectively the test results of the total nitrogen retention rate of the composts obtained in Example 1, Examples 20-29 and Comparative Examples 4-5 and the test results of the removal rate of organic pollutants. The test results show that

[0141] In Comparative Example 4, the biochar carrier was not treated with a plasma jet during the preparation of the initial composite microbial agent, and in Comparative Example 5, the initial composite microbial agent was not treated with wet-dry cycling during the preparation of the composite microbial agent. The total nitrogen retention rate of the compost obtained in Comparative Example 4 or Comparative Example 5 was significantly lower than that in Examples 1, 20-29, and the removal rate of organic pollutants in the organic solid waste was also significantly decreased.

[0142] Comparing Examples 1, 20-29, it can be seen that whether the biochar carrier is treated with a plasma jet, the process parameters of the plasma jet treatment, the effective viable count, whether the initial composite microbial agent is treated with wet-dry cycling and the process parameters of the wet-dry cycling treatment, the composition of the trace element solution, and the size of the aeration volume during the composting process will all reduce the total nitrogen retention rate of the compost and the removal rate of organic pollutants in the organic solid waste. Through comprehensive comparison, it can be seen that the composting effect of Example 1 is better.

[0143] Inspired by the ideal embodiments of the present invention described above, through the above description, relevant staff can completely make various changes and modifications without departing from the technical idea of the present invention. The technical scope of the present invention is not limited to the content in the specification, and its technical scope must be determined according to the scope of the claims.

Claims

1. A composite microbial agent, characterized in that: The initial composite microbial agent is subjected to a dry-wet cycle treatment for 6-8 times to obtain a composite microbial agent. The time for one dry-wet cycle treatment is 24 hours. The one dry-wet cycle treatment includes the following steps: At room temperature, the initial composite bacterial agent is soaked in a trace element solution for 13-16 hours, then dried at 65-75°C for 7-8 hours, and then cooled at 15-20°C; the initial composite bacterial agent includes a biochar carrier and biological bacteria attached to the biochar carrier; the trace element solution is a uniform mixed solution formed by zinc chloride, copper chloride, sodium titanate and water; the biological bacteria include thermophilic bacteria, Bacillus and Aspergillus.

2. A composite microbial agent according to claim 1, characterized in that: The preparation method of the initial composite bacterial agent comprises the following steps: (1) treating the biochar carrier with a plasma jet, wherein the gas used for the plasma jet treatment is a gas mixture composed of oxygen and helium in a volume ratio of 0.05-0.15:1, the power supply power is 150-250 W, and the treatment time is 1-2 min; (2) The effective viable count was 0.8×10 9 ~1×10 9 CFU / mL of thermophilic bacteria solution, Bacillus solution and Aspergillus solution were mixed uniformly in a volume ratio of 1-2:1:1 to obtain a microbial solution; (3) The biochar carrier treated with plasma jet was evenly mixed with the microbial liquid at a dosage ratio of 0.7-0.9 g:1 mL, and then naturally dried at room temperature to obtain an initial composite bacterial agent.

3. A composite microbial agent according to claim 2, characterized in that: The preparation method of the biochar carrier comprises the following steps: (1) The biochar raw material is pyrolyzed at 700-750° C. under nitrogen protection for 11-13 hours, and then passed through a 50-80 mesh sieve to obtain biochar powder, and the biochar powder is soaked in a sulfuric acid aqueous solution with a mass concentration of 5-6% for 15-18 hours. After the soaking treatment is completed, the biochar powder is dried; (2) the biochar powder dried in step (1) is uniformly mixed with a dopamine aqueous solution having a mass concentration of 1-2 g / L, a sodium hydroxide aqueous solution having a mass concentration of 5-6%, and white carbon black in a mass ratio of 0.8-1:0.5:4:0.4, and then the reaction system is heated to 120-130° C., stirred at a constant temperature for 25-35 min, and then the mixture is cooled to room temperature, and the obtained mixture is subjected to solid-liquid separation, washed with water, and dried to obtain a mixture to obtain an initial carrier; (3) Under nitrogen protection, the initial carrier is subjected to low-temperature heat treatment at a temperature of 190-240° C. for a treatment time of 2.5-4 h, and then naturally cooled to room temperature to obtain a biochar carrier.

4. A composite microbial agent according to claim 3, characterized in that: The biochar raw material includes one or a combination of two or more of crop straw, red pine nut shell or bamboo.

5. A composite microbial agent according to claim 1, characterized in that: The trace elements in the trace element solution are composed of zinc chloride, copper chloride and sodium titanate in a mass ratio of 1-2:0.4-0.6:0.2-0.5, and the total mass concentration of the trace elements in the trace element solution is 1-5 g / L.

6. A composite microbial agent according to claim 1, characterized in that: The thermophilic bacteria is thermophilic aerophilic thiamine-lytic Bacillus.

7. A composite microbial agent according to claim 1, characterized in that: The bacillus is Bacillus subtilis.

8. A composite microbial agent according to claim 1, characterized in that: The Aspergillus is Aspergillus niger.

9. A method for resource treatment of organic solid waste using electric field enhancement, characterized in that: The following steps are involved: S1. Pre-treatment of organic solid waste: The organic solid waste is crushed and mixed with water to obtain a compost material, wherein the water content of the compost material is 55-65%, the C / N value is 22-28, and the pH value of the compost material is adjusted to 6-7; S2. Aerobic composting in stages: (1) Heating stage: Add the composite microbial agent obtained in claim 1 in an amount of 7-10 wt % by weight of the compost to the compost obtained in step S1, start composting, and heat the compost from room temperature to 80±5° C. During the heating process, the compost is ventilated once for every 10-15° C. heating, and the ventilation volume is 0.5-1 L / (min·kg) each time. When the C / N value of the compost drops to 50-60% of the original carbon-nitrogen ratio, the compost is ventilated once for every 4-6° C. heating, and the ventilation volume is 1.2-1.5 L / (min·kg) each time. (2) Ultra-high temperature stage: After the heating is completed, the temperature is kept at 5-7 days. During the heating, the compost is ventilated once every 2-4 hours, and the ventilation volume each time is 0.1-0.2L / (min·kg). When the C / N value of the compost continues to decrease by 30-40% of the C / N value of the compost after the heating is completed, an electric field is applied to the compost, and the voltage is 5-10V; (3) Cooling stage: After step (2) is completed, a composite microbial agent accounting for 2-3 wt% of the compost is added to the compost, and after the compost is turned evenly, the compost is naturally cooled to 25-35°C. During the cooling process, the compost is ventilated once every 5-10°C, and the ventilation volume each time is 1.2-1.5 L / (min·kg); (4) Low temperature stage: After the cooling in step (3) is completed, the compost is kept warm for 4-5 days. During the warming process, an electric field is continuously applied to the compost, and the compost is ventilated once every 2-4 hours, with a ventilation volume of 0.1-0.2L / (min·kg) each time and a voltage of 5-10V; During the entire step S2, the pile is turned over every 4 days.

10. The method for resource treatment of organic solid waste using electric field enhancement according to claim 9, characterized in that: pH adjusters include hydrochloric acid or sodium hydroxide aqueous solution.

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