Method for synergistically promoting biogas residue aerobic composting based on charcoal coupled zeolite

Abstract

The invention relates to a method for synergistically promoting biogas residue aerobic composting based on charcoal coupled zeolite, and belongs to the technical field of biogas residue aerobic composting. In order to solve the problem of low biogas residue aerobic composting treatment efficiency, biogas residues, straws, biochar and zeolite are mixed for aerobic composting, the biogas residues and the straws are compost bodies, the addition amount of the biochar is 1-10% of the dry weight of the compost bodies, and the addition amount of the zeolite is 1-10% of the dry weight of the compost bodies. According to the method, the biochar and the zeolite are added into a compost body of biogas residue aerobic compost, so that the maturity of the compost is remarkably improved, the high-temperature period of the biogas residue compost is prolonged to 7-8 days, the seed germination index is increased by 50.33%-96.14%, and the highest organic matter degradation rate of a synergistic addition group of the biochar and the zeolite reaches 14.24%. Therefore, the efficiency of aerobic composting of the biogas residues and the quality of the product are improved by synergistically adding the charcoal and the zeolite, and resource utilization of the biogas engineering residues is facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of aerobic composting of biogas residue, and in particular relates to a method for synergistically promoting aerobic composting of biogas residue based on biochar coupling with zeolite. Background Art

[0002] Biogas residue is an organic waste produced during the biogas fermentation process. It contains rich nutrients and organic matter, such as nitrogen, phosphorus, potassium and other nutrients required by plants, and has a high resource utilization value. Biogas residue can be converted into high-quality organic fertilizer through aerobic composting and other processes. This organic fertilizer is not only rich in organic matter and nutrients, but also natural, safe and environmentally friendly. It is an important source of fertilizer in agricultural production.

[0003] During the aerobic composting process, microorganisms will decompose the organic matter in the biogas residue and convert it into stable humus, thereby improving the fertilizer efficiency. Humus is an important component of the soil and can improve the soil structure and increase the soil's ability to retain water and fertilizer. Biogas residue may contain some substances that are harmful to plants. Through aerobic composting, these harmful substances can be effectively degraded, thereby reducing the phytotoxicity of biogas residue. This makes the treated biogas residue more suitable for use as an organic fertilizer and will not cause harm to crops. Aerobic composting can effectively reduce the organic matter in biogas residue and reduce its pollution to the environment. Compared with direct discharge or landfill, aerobic composting is a more environmentally friendly treatment method.

[0004] Aerobic composting is the process of aerobic bacteria absorbing, oxidizing and decomposing waste under good ventilation and sufficient oxygen conditions. Compared with anaerobic composting, aerobic microorganisms have a higher demand for oxygen, and the decomposition process of organic matter is relatively complex. Many factors lead to lower efficiency of aerobic composting, which requires more time and space to accommodate and process compost materials. Summary of the invention

[0005] In order to solve the problem of low efficiency of aerobic composting of biogas residue, the present invention provides a method for synergistically promoting aerobic composting of biogas residue based on biochar coupling zeolite.

[0006] The technical solution of the present invention:

[0007] A method for promoting aerobic composting of biogas residue based on biochar coupling zeolite, wherein biogas residue, straw, biochar and zeolite are mixed for aerobic composting, the biogas residue and straw form a pile, the biochar is added in an amount of 1 to 10% of the dry weight of the pile, and the zeolite is added in an amount of 1 to 10% of the dry weight of the pile.

[0008] Furthermore, the fresh weight ratio of the biogas residue to the straw is 4:1.

[0009] Furthermore, the initial carbon-nitrogen ratio of the pile is 25-30:1, and the initial moisture content is 45-55%.

[0010] Furthermore, the straw is corn straw chopped into 1 to 3 cm pieces.

[0011] Furthermore, the biochar is wheat straw biochar, which is prepared by pyrolysis at 520°C, and the specific surface area of ​​the biochar is 132.39 m 2 ·g -1 The average pore volume is 0.08 cm 3 ·g -1 , the average pore size is 2.38nm.

[0012] Furthermore, the biochar has a moisture content of 17.47±0.17%, an organic matter content of 33.28±1.24%, a pH of 5.86±0.12, a conductivity of 0.35±0.01 mS / cm, a total nitrogen content of 0.68±0.07% TS, a total carbon content of 48.28±0.75% TS, and a carbon-nitrogen ratio of 71.44±8.53.

[0013] Furthermore, the specific surface area of ​​the zeolite is 18.82 m 2 ·g -1 The average pore volume is 0.03 cm 3 ·g -1 The average pore size is 5.89 nm, the water content of the zeolite is 5.22±0.05%, the organic matter content is 4.64±0.45%, the pH is 9.07±0.12, and the conductivity is 0.02±0.01 mS / cm.

[0014] Furthermore, the sludge has a moisture content of 60.61±1.19%, an organic matter content of 75.75±0.80%, a pH of 9.07±0.01, an electrical conductivity of 0.98±0.02 mS / cm, a total nitrogen content of 1.5±0.05% TS, a total carbon content of 34.12±1.23% TS, and a carbon-nitrogen ratio of 22.70±0.63.

[0015] Furthermore, the straw has a moisture content of 8.39±0.12%, an organic matter content of 94.10±0.34%, a pH of 5.29±0.09, an electrical conductivity of 4.12±0.14 mS / cm, a total nitrogen content of 0.77±0.04% TS, a total carbon content of 32.54±0.49% TS, and a carbon-nitrogen ratio of 42.57±1.32.

[0016] Furthermore, ventilation was performed by manual compost turning on days 0, 3, 6, 9, 14, 21, 28, 35 and 49 of aerobic composting.

[0017] Beneficial effects of the present invention:

[0018] The present invention significantly improves the maturity of compost by adding biochar and zeolite to the pile of aerobic composting of biogas residue, which is manifested in the extension of the thermophilic stage, the increase of GI (seed germination index) and the acceleration of organic matter degradation rate. Especially in terms of lignocellulose decomposition, the combined use of biochar and zeolite is better than using them alone. This improvement stems from the positive impact on the bacterial community structure, which significantly increases the number of key lignocellulose degrading microorganisms. The present invention extends the high temperature period of biogas residue composting to 7 to 8 days, and the seed germination index increases by 50.33% to 96.14%, wherein the organic matter degradation rate of the group with the synergistic addition of the two reaches up to 14.24%. Therefore, the synergistic addition of biochar and zeolite improves the efficiency of aerobic composting of biogas residue and the quality of the product, which is more conducive to the resource utilization of biogas project residues. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a comparison chart of temperature changes during aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1;

[0020] Figure 2 It is a comparison chart of pH changes during aerobic composting in Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1;

[0021] Figure 3 It is a comparison diagram of the conductivity changes during the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1;

[0022] Figure 4 It is a comparison chart of GI changes in the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1;

[0023] Figure 5 It is a comparison chart of the increase rate of total nitrogen content in the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1;

[0024] Figure 6 It is a comparison chart of the total carbon content loss rate in the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1;

[0025] Figure 7 It is a comparison chart of carbon-nitrogen ratio changes in the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1;

[0026] Figure 8 It is a comparison chart of the degradation rate of organic matter in the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1;

[0027] Fig. 9It is a comparison chart of the relative abundance changes of bacterial communities at the phylum level during the aerobic composting processes of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1. DETAILED DESCRIPTION

[0028] The technical solution of the present invention is further described below in conjunction with the embodiments, but it is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the protection scope of the present invention. The process equipment or devices not specifically noted in the following embodiments are all conventional equipment or devices in the art. If not specifically specified, the raw materials used in the embodiments of the present invention can be obtained commercially; if not specifically specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0029] Example 1

[0030] This embodiment provides a method for synergistically promoting aerobic composting of biogas residue based on biochar coupling with zeolite.

[0031] In this composting experiment, anaerobic digestion residue (BR) was used as the raw material matrix, and corn straw (CS) chopped into 1-3 cm was used as the bulking agent.

[0032] BR was obtained from a large-scale biogas project of Heilongjiang Boneng Green Energy Technology Co., Ltd., and CS was purchased from Hailun Farm in Heilongjiang Province.

[0033] Wheat straw biochar (B) and zeolite (Z) were used as additives. Biochar was purchased from Henan Housen Environmental Protection Technology Co., Ltd., and zeolite was purchased from Gongyi Huizhi Water Supply Materials Co., Ltd.

[0034] The biochar was prepared by pyrolysis at 520 °C, and the BET specific surface area of ​​the biochar was 132.39 m 2 ·g -1 The average pore volume is 0.08 cm 3 ·g -1 The average pore size is 2.38 nm. The BET specific surface area of ​​zeolite is 18.82 m 2 ·g -1 The average pore volume is 0.03 cm 3 ·g -1 , the average pore size is 5.89nm.

[0035] The basic physical and chemical properties of composting raw materials and additives are shown in Table 1.

[0036] Table 1

[0037]

[0038]

[0039] The aerobic composting method of biogas residue in this embodiment adopts small-scale natural composting, and the overall pile is triangular in shape, 0.8m long, 1.1m wide and 1.05m high. According to the physical and chemical properties of biogas residue and straw (Table 1), the initial C / N ratio of the pile is adjusted to about 28:1, and the initial moisture content is adjusted to about 50%. Biogas residue and straw are mixed and composted at a fresh weight ratio of 4:1, and the total weight of the pile is 90kg. The amount of biochar added is 10% of the dry weight of the pile, and the amount of zeolite added is 10% of the dry weight of the pile. Ventilation is carried out by manual turning of the pile on the 0th, 3rd, 6th, 9th, 14th, 21st, 28th, 35th and 49th days of composting.

[0040] Example 2

[0041] This embodiment provides a method for synergistically promoting aerobic composting of biogas residue based on biochar coupling with zeolite.

[0042] The difference between this embodiment and embodiment 1 is that the aerobic composting method of biogas residue in this embodiment adopts small-scale natural composting, and the pile is triangular in shape as a whole, with a length of 0.8m, a width of 1.1m, and a height of 1.05m. According to the physical and chemical properties of biogas residue and straw (Table 1), the initial C / N ratio of the pile is adjusted to about 28:1, and the initial moisture content is adjusted to about 50%. Biogas residue and straw are mixed and composted at a fresh weight ratio of 4:1, and the total weight of the pile is 90kg. The amount of biochar added is 5% of the dry weight of the pile, and the amount of zeolite added is 5% of the dry weight of the pile. Ventilation is carried out by manual turning of the pile on the 0th, 3rd, 6th, 9th, 14th, 21st, 28th, 35th and 49th days of composting.

[0043] Example 3

[0044] This embodiment provides a method for synergistically promoting aerobic composting of biogas residue based on biochar coupling with zeolite.

[0045] The difference between this embodiment and embodiment 1 is that the aerobic composting method of biogas residue in this embodiment adopts small-scale natural composting, and the pile is triangular in shape as a whole, with a length of 0.8m, a width of 1.1m, and a height of 1.05m. According to the physical and chemical properties of biogas residue and straw (Table 1), the initial C / N ratio of the pile is adjusted to about 28:1, and the initial moisture content is adjusted to about 50%. Biogas residue and straw are mixed and composted at a fresh weight ratio of 4:1, and the total weight of the pile is 90kg. The amount of biochar added is 10% of the dry weight of the pile, and the amount of zeolite added is 5% of the dry weight of the pile. Ventilation is carried out by manual turning of the pile on the 0th, 3rd, 6th, 9th, 14th, 21st, 28th, 35th and 49th days of composting.

[0046] Example 4

[0047] This embodiment provides a method for synergistically promoting aerobic composting of biogas residue based on biochar coupling with zeolite.

[0048] The difference between this embodiment and embodiment 1 is that the aerobic composting method of biogas residue in this embodiment adopts small-scale natural composting, and the pile is triangular in shape as a whole, with a length of 0.8m, a width of 1.1m, and a height of 1.05m. According to the physical and chemical properties of biogas residue and straw (Table 1), the initial C / N ratio of the pile is adjusted to about 28:1, and the initial moisture content is adjusted to about 50%. Biogas residue and straw are mixed and composted at a fresh weight ratio of 4:1, and the total weight of the pile is 90kg. The amount of biochar added is 5% of the dry weight of the pile, and the amount of zeolite added is 10% of the dry weight of the pile. Ventilation is carried out by manual turning of the pile on the 0th, 3rd, 6th, 9th, 14th, 21st, 28th, 35th and 49th days of composting.

[0049] Comparative Example 1

[0050] This comparative example provides a method for aerobic composting using only biogas residue and corn straw without adding biochar and zeolite.

[0051] The difference between this comparative example and Example 1 is that the aerobic composting method of biogas residue in this comparative example adopts small-scale natural composting, and the pile is triangular in shape, 0.8m long, 1.1m wide and 1.05m high. According to the physical and chemical properties of biogas residue and straw (Table 1), the initial C / N ratio of the pile is adjusted to about 28:1, and the initial moisture content is adjusted to about 50%. Biogas residue and straw are mixed and composted at a fresh weight ratio of 4:1, and the total weight of the pile is 90kg. Ventilation is carried out by manual turning of the pile on the 0th, 3rd, 6th, 9th, 14th, 21st, 28th, 35th and 49th days of composting.

[0052] Comparative Example 2

[0053] This comparative example provides an aerobic composting method with only biochar added.

[0054] The difference between this comparative example and Example 1 is that the aerobic composting method of biogas residue in this comparative example adopts small-scale natural composting, and the pile is triangular in shape as a whole, with a length of 0.8m, a width of 1.1m, and a height of 1.05m. According to the physical and chemical properties of biogas residue and straw (Table 1), the initial C / N ratio of the pile is adjusted to about 28:1, and the initial moisture content is adjusted to about 50%. Biogas residue and straw are mixed and composted at a fresh weight ratio of 4:1, and the total weight of the pile is 90kg. The amount of biochar added is 10% of the dry weight of the pile. Ventilation is carried out by manual turning of the pile on the 0th, 3rd, 6th, 9th, 14th, 21st, 28th, 35th and 49th days of composting.

[0055] Comparative Example 3

[0056] This comparative example provides an aerobic composting method with only zeolite added.

[0057] The difference between this comparative example and Example 1 is that the aerobic composting method of biogas residue in this comparative example adopts small-scale natural composting, and the pile is triangular in shape as a whole, with a length of 0.8m, a width of 1.1m, and a height of 1.05m. According to the physical and chemical properties of biogas residue and straw (Table 1), the initial C / N ratio of the pile is adjusted to about 28:1, and the initial moisture content is adjusted to about 50%. Biogas residue and straw are mixed and composted at a fresh weight ratio of 4:1, and the total weight of the pile is 90kg. The amount of zeolite added is 10% of the dry weight of the pile. Ventilation is carried out by manual turning of the pile on the 0th, 3rd, 6th, 9th, 14th, 21st, 28th, 35th and 49th days of composting.

[0058] Test Example 1

[0059] Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1 were used as four treatment groups. Ventilation and sample collection were carried out by manual compost turning on the 0th, 3rd, 6th, 9th, 14th, 21st, 28th, 35th and 49th days of composting.

[0060] Collect samples from the top, middle and bottom of the pile respectively, and mix them thoroughly after taking the samples.

[0061] 300g of samples were collected from each treatment group and divided into three parts. The first part was stored at 4℃ as a fresh sample for the determination of physical and chemical properties; the second part was air-dried and ground through a 100-mesh sieve for the determination of indicators such as lignocellulose; the third part was stored at -20℃ for microbial analysis.

[0062] The analysis method of this test case is:

[0063] Every day at 9:00 a.m., 14:00 p.m. and 21:00 p.m., the temperature of the upper, middle and lower parts of the pile was measured using a thermometer to obtain the average temperature.

[0064] The compost samples were dried in an oven at 105°C to constant weight to obtain the moisture content (MC).

[0065] The organic matter (OM) content was determined by the muffle furnace ignition loss method (550°C, 4 h).

[0066] The compost samples were leached with deionized water at a ratio of 1:10 (w / v) at 180 rpm for 1 h. The pH value of the leaching solution was measured using a pH meter (Lecithin, Shanghai).

[0067] EC was measured using a conductivity meter (Leci, Shanghai).

[0068] The contents of C and N in the compost samples were analyzed by an element analyzer (Elementar, Germany).

[0069] The cellulose, hemicellulose and lignin contents were determined using an ANKOM220 semi-automatic cellulose analyzer according to the Van Soest cellulose determination method.

[0070] The seed germination index (GI) was determined according to the method of Zhong et al. Cabbage seeds were selected. 5 ml of compost sample extract was used to culture the seeds, and ultrapure water was used as the control group. The calculation formula of GI is as follows:

[0071] GI (%) = (seed germination rate of compost extract × root length) / (seed germination rate of ultrapure water × root length) × 100%

[0072] The results of this test case:

[0073] 1. Temperature

[0074] Temperature is an important indicator of the composting process, which is closely related to the degradation of organic matter and the activity of microorganisms. Figure 1 The temperature change comparison diagram of the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1 is shown; Figure 1 It can be seen that the temperature change process of each test group follows the four typical stages of composting: heating period, high temperature period, cooling period and maturity period. That is, the overall temperature shows a trend of first rising and then falling, and finally tends to room temperature. During this period, due to turning the pile, the temperature will fluctuate from rising to falling. In the early stage of composting, the temperature of each test group rose rapidly and exceeded 50℃ on the second day, entering the high temperature period.

[0075] Compared with the control group of Comparative Example 1, the exogenous addition of biochar and zeolite prolonged the high temperature duration of sludge composting and increased the peak temperature of the composting, indicating that biochar and zeolite accelerated the composting efficiency.

[0076] (II) pH and conductivity

[0077] pH value is a commonly used indicator to evaluate the maturity of compost. Figure 2 The pH changes during the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1 are compared. Figure 2 It can be seen that compared with the control group of Comparative Example 1, the initial pH values ​​of the composts in Comparative Example 2, Comparative Example 3 and Example 1 were increased due to the addition of biochar and zeolite, which may be because the biochar and zeolite themselves have alkaline properties.

[0078] Electrical conductivity (EC) reflects the mineralization of organic matter in the compost and the level of salt it contains. When the salt content in the pile increases, the EC will also increase. However, too high salt will reduce the germination rate of seeds and have a negative impact on plant growth, so the EC of the compost should not be too high. Figure 3The conductivity change comparison diagram of the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1 is shown; Figure 3 It can be seen that the initial EC of each test group was below 2 mS / cm, and the initial EC value was relatively low compared with composting using other types of raw materials.

[0079] (III) Seed germination index GI

[0080] Seed germination index (GI) is a common biological index for evaluating the phytotoxicity and maturity of compost. According to previous research reports, when the GI value is higher than 80%, the compost is mature and non-phytotoxic. Figure 4 The GI changes of the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1 are compared; Figure 4 It can be seen that the initial GI values ​​of each test group are all above 80%. Compared with other composting materials, such as food waste, sludge and livestock and poultry manure, the initial GI value of biogas residue composting is relatively high, which may be because biogas residue itself is a humus raw material, providing rich nutrients for seed germination.

[0081] (IV) Carbon content, nitrogen content and carbon-nitrogen ratio

[0082] The main nutrients in compost are carbon and nitrogen. When organic matter is degraded, the nutrients in the compost decrease, which leads to a gradual decrease in TC, TN and C / N ratio. Figure 5 It is a comparison chart of the increase rate of total nitrogen content in the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1; Figure 6 It is a comparison chart of the total carbon content loss rate in the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1; Figure 7 The carbon-nitrogen ratio of the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1 is compared; Figure 5-Figure 7 It can be seen that compared with the control group of Comparative Example 1, the loss rate of total carbon content was increased after adding biochar and adding biochar and zeolite together, indicating that biochar and zeolite increased the activity of microorganisms in the pile and promoted the utilization of organic matter.

[0083] The total nitrogen content increase rate in the control group of Comparative Example 1 decreased by 0.17%, while the total nitrogen content increase rates of Comparative Example 2, Comparative Example 3 and Example 1 increased by 0.52%, 0.8% and 0.26%, respectively. This shows that the addition of biochar and zeolite reduced the loss of nitrogen, which may be due to the adsorption and ion exchange capacity of both, which is conducive to the function of microorganisms. Among them, zeolite has the best effect on nitrogen retention, followed by biochar.

[0084] (V) Degradation of organic matter

[0085] Composting can degrade organic matter into small molecules, which provide energy for microorganisms to carry out their life activities. Then, under the action of microorganisms, organic matter is transformed into humus and inorganic minerals. Figure 8 The comparison diagram of the degradation rate of organic matter in the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1 is shown; Figure 8 It can be seen that the organic matter degradation rates of the blank control group, comparative example 1 and comparative example 2 are 5.69%, 4.28% and 10.76% respectively, while that of Example 1 is as high as 14.24%. This shows that compared with no addition of biochar and zeolite or the addition of both alone, the combined addition of the two is more conducive to the degradation of organic matter and is more effective in improving the efficiency of biogas residue composting.

[0086] (VI) Changes in microbial community structure

[0087] Fig. 9 It is a comparison chart of the relative abundance changes of bacterial communities at the phylum level during the aerobic composting process of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1. The abscissa represents the 0th day, the 3rd day, the 6th day, the 21st day and the 49th day of the composting of Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1, respectively, and the ordinate represents the changes in the relative abundance of bacterial communities at the phylum level during the aerobic composting process.

[0088] Actinobacteria is a mesophilic or thermophilic bacteria that can promote the degradation of lignocellulose, mainly at the end of composting. At the end of composting, the relative abundance of Actinobacteria in Comparative Example 1, Comparative Example 2, Comparative Example 3 and Example 1 was 23.92%, 29.43%, 32.05% and 40.95%, respectively. It shows that the addition of biochar and zeolite provides a suitable habitat for Actinobacteria, which is conducive to the degradation of lignocellulose by Actinobacteria. Compared with the addition of biochar and zeolite alone, the final relative abundance of Actinobacteria is higher when the two are added together.

[0089] As the composting temperature increased, the relative abundance of Proteobacteria and Bacteroidetes decreased in all treatment groups. It may be because Proteobacteria and Bacteroidetes are not resistant to high temperatures, and the dominant bacterial community in the composting process mainly evolved into high-temperature resistant Firmicutes. Previous studies have found that Proteobacteria plays a key role in the decomposition of small molecules and the carbon-nitrogen cycle. In the later stage of composting, the relative abundance of Proteobacteria in Comparative Example 2, Comparative Example 3 and Example 1 was higher than that in Comparative Example 1. Proteobacteria is the main denitrifying bacteria in the composting process, so the addition of biochar and zeolite enhances the denitrification activity of the compost.

Claims

1. A method for promoting aerobic composting of biogas residue based on biochar coupling with zeolite, characterized in that: Biogas residue, straw, biochar and zeolite are mixed for aerobic composting, wherein the biogas residue and straw form a pile, the biochar is added in an amount of 1-10% of the dry weight of the pile, and the zeolite is added in an amount of 1-10% of the dry weight of the pile.

2. According to claim 1, a method for promoting aerobic composting of biogas residue by coupling zeolite with biochar, characterized in that: The fresh weight ratio of the biogas residue to the straw is 4:

1.

3. A method for promoting aerobic composting of biogas residue based on biochar coupling with zeolite according to claim 1 or 2, characterized in that: The initial carbon-nitrogen ratio of the pile is 25-30:1, and the initial moisture content is 45-55%.

4. The method of promoting aerobic composting of biogas residue based on biochar coupling with zeolite according to claim 3, characterized in that: The straw is corn straw chopped into 1-3 cm pieces.

5. The method of promoting aerobic composting of biogas residue based on biochar coupling with zeolite according to claim 4, characterized in that: The biochar is wheat straw biochar, which is prepared by pyrolysis at 520°C. The specific surface area of ​​the biochar is 132.39 m 2 ·g -1 The average pore volume is 0.08 cm 3 ·g -1 , the average pore size is 2.38nm.

6. The method of promoting aerobic composting of biogas residue based on biochar coupling with zeolite according to claim 5, characterized in that: The biochar has a moisture content of 17.47±0.17%, an organic matter content of 33.28±1.24%, a pH of 5.86±0.12, an electrical conductivity of 0.35±0.01 mS / cm, a total nitrogen content of 0.68±0.07% TS, a total carbon content of 48.28±0.75% TS, and a carbon-nitrogen ratio of 71.44±8.

53.

7. The method of promoting aerobic composting of biogas residue based on biochar coupling with zeolite according to claim 6, characterized in that: The specific surface area of ​​the zeolite is 18.82 m 2 ·g -1 The average pore volume is 0.03 cm 3 ·g -1 The average pore size is 5.89 nm, the water content of the zeolite is 5.22±0.05%, the organic matter content is 4.64±0.45%, the pH is 9.07±0.12, and the conductivity is 0.02±0.01 mS / cm.

8. The method of promoting aerobic composting of biogas residue based on biochar coupling with zeolite according to claim 7, characterized in that: The sludge has a moisture content of 60.61±1.19%, an organic matter content of 75.75±0.80%, a pH of 9.07±0.01, an electrical conductivity of 0.98±0.02 mS / cm, a total nitrogen content of 1.5±0.05% TS, a total carbon content of 34.12±1.23% TS, and a carbon-nitrogen ratio of 22.70±0.

63.

9. The method of promoting aerobic composting of biogas residue based on biochar coupling with zeolite according to claim 8, characterized in that: The straw has a moisture content of 8.39±0.12%, an organic matter content of 94.10±0.34%, a pH of 5.29±0.09, an electrical conductivity of 4.12±0.14 mS / cm, a total nitrogen content of 0.77±0.04% TS, a total carbon content of 32.54±0.49% TS, and a carbon-nitrogen ratio of 42.57±1.

32.

10. The method for promoting aerobic composting of biogas residue based on biochar coupling with zeolite according to claim 9, characterized in that: During aerobic composting, ventilation was carried out by manual turning of the compost on days 0, 3, 6, 9, 14, 21, 28, 35 and 49.

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