Compost maturity evaluation method and application

Abstract

The invention belongs to the technical field of compost, and particularly relates to a compost maturity evaluation method and application. The compost maturity evaluation method comprises the following steps: recording a temperature curve in a compost process, and taking the time when the compost temperature appears on a platform or the whole compost period as a calculation point; calculating the total heat generated from the beginning of composting to the calculation point, and recording the total heat as sigma Q; respectively measuring a seed germination rate index, humus concentration and organic matter concentration of compost before composting and at a calculation point; the difference value of the seed germination rate indexes, the difference value of the humus concentration and the difference value of the organic matter concentration are calculated and recorded as delta GI, delta HA and delta OM respectively; and calculating an organic fertilizer effect F and a humic index f, and evaluating the composting degree of the compost according to the f value. According to the method, each evaluation index is comprehensively considered, and the composting effects of different composting raw materials, different composting parameters and the like can be compared through the f value, so that the composting effects of different composts can be uniformly evaluated.

Description

Technical Field

[0001] The present invention belongs to the technical field of composting, and particularly relates to a method for evaluating compost maturity and its application. Background Art

[0002] Aerobic composting is a process in which organic solid waste is decomposed and synthesized into new high-molecular organic matter, such as humus and other biochemical processes, through the decomposition and synthesis of microorganisms under aerobic conditions. In this process, a large amount of heat is released. Since the raw materials of composting have low moisture content, the heat will accumulate, resulting in high temperatures, which can achieve the effect of killing pathogens, eggs, and weed seeds. At the same time, the composted product contains elements such as N, P, and K that can be utilized by plants, and is an important source of organic fertilizer elements. Therefore, aerobic composting technology is one of the main methods for organic solid waste treatment and resource utilization at present.

[0003] Generally, the indicators for evaluating compost maturity include physical indicators, chemical indicators, and biological indicators, etc.

[0004] (1) Physical indicators or apparent analysis indicators. Temperature is an important indicator for measuring the maturity of compost. By regularly measuring the temperature of the compost pile, the activity of the internal microbial community and the composting process can be understood. Generally, it is appropriate for the temperature of the compost pile to be close to or slightly higher than room temperature. Excessive temperature may mean that the compost is not fully mature. Odor is also an intuitive method for judging compost maturity. Mature compost should emit the smell of soil, while immature compost may produce pungent and unpleasant odors. The touch method is also a simple and effective evaluation method. By touching the compost, the looseness of its feel can be felt. Mature compost should feel loose and be easy to break up, while immature compost may feel firm and sticky.

[0005] (2) Chemical indicators. During the composting process, the unstable organic matter in the composting materials is decomposed and transformed into carbon dioxide, water, minerals, and stabilized organic matter, and the organic matter content of the composting materials changes significantly. Therefore, the maturity can be characterized by measuring some parameters reflecting the change of organic matter (such as chemical oxygen demand (COD), biochemical oxygen demand (BOD), and volatile solids (VS), etc.) and the change rules of certain organic matter during the composting process. In addition, it also includes: ammonia nitrogen index, humification index, carbon-nitrogen ratio (C / N), organic acids, etc.

[0006] (3) Biological indicators. The production of carbon dioxide, the oxygen consumption rate of microorganisms, enzyme activity, adenosine triphosphate (ATP), and the quantity and types of microorganisms are used to characterize the stability and maturity of compost. Seed germination rate: Immature compost products have an inhibitory effect on plant growth. Therefore, the growth status of plants in the mixture of compost and soil can be used to evaluate the maturity of compost. Considering the practical significance of compost maturity, this is the most persuasive evaluation method.

[0007] However, physical, chemical, and biological indicators all have their own drawbacks when evaluating compost maturity. Physical indicators are usually easy to operate and qualitatively evaluate, but machine learning and computer vision methods may be needed for quantitative evaluation. For example, temperature is an important physical indicator during the composting process, which can intuitively reflect the degree of compost maturity. However, the change in temperature may be affected by environmental factors, so it needs to be measured and analyzed under specific conditions. Chemical indicators can quantitatively evaluate the maturity, but the evaluation results are largely affected by the characteristics of compost raw materials. For example, pH value is a commonly used chemical indicator, which can reflect the acid-base balance during the composting process. However, different compost raw materials may have different pH value ranges, which may lead to deviations in the evaluation results. Biological indicators such as the seed germination rate index are currently authoritative indicators for evaluating compost maturity, but due to the lack of standardized seeds and standardized methods, different plant seeds may have different tolerances and responses to compost, which may make it difficult to compare the results between different studies. In addition, the measurement of biological indicators usually takes a long time, which may affect the evaluation efficiency.

[0008] In addition, due to the large differences in different compost raw materials, operating parameters, etc., there is currently no unified indicator to evaluate their maturity, resulting in the inability to evaluate the superiority of composting processes from different raw material sources. Even due to different operating parameters, it is often difficult to compare and evaluate the processes with the same raw material but different operating parameters. To improve the accuracy and efficiency of evaluation, a more standardized and general maturity evaluation system needs to be established or rapid, accurate, and economical detection indicators need to be developed to guide compost production practices.

[0009] Therefore, it is of great significance to provide an evaluation method for compost maturity that can compare the composting effects of different compost raw materials and different processes. Summary of the Invention

[0010] The present invention aims to solve one or more of the above-mentioned technical problems existing in the prior art and at least provide a beneficial option. Specifically, the present invention provides an evaluation method for compost maturity, which can compare the composting effects of different compost raw materials and different processes to judge their maturity degree; and it does not require large-scale instruments, can be quickly measured on-site, is simple to operate, and has low costs.

[0011] The inventive concept of the present invention: Composting is a process of microbial-driven oxidation and decomposition of organic matter and synthesis of humus. The water content of the compost raw materials is relatively low, which is prone to heat accumulation and temperature rise. Temperature is the most direct indicator of compost stabilization. When the temperature of the compost pile no longer changes, it indicates that the compost is in a relatively stable state, and the number of days of composting at this point is used as the calculation point for heat to calculate the cumulative heat generated during the composting process, or the entire composting cycle is used as the calculation point. The more heat is generated, indicating that the organic matter in the compost raw materials is more thoroughly oxidized and decomposed, and the heat accumulation is beneficial to promoting the composting process. Organic matter is the original substance for microbial oxidation and decomposition and is the fundamental source for generating heat. Calculating the difference in organic matter concentration can show how much organic matter can be utilized by microorganisms and generate heat. Composting is also a process of humus synthesis. The levels of humus (HA) and seed germination index (GI) in the compost product are crucial for plant growth. High levels of HA and GI are beneficial to plant growth, and these two parameters are mainly evaluated from the perspective of the value of organic fertilizers. The present invention calculates the organic fertilizer effect F that can be generated by the unit of organic matter available for microorganisms during the composting process at a specific calculation point. 计算点 According to the organic fertilizer standard, when GI is greater than or equal to 70%, the compost reaches the maturity standard. Taking this as the reference point, calculate the organic fertilizer effect F that can be generated by the unit of organic matter available for microorganisms during the composting process when GI is greater than or equal to 70%. 基准点 Furthermore, the f value is obtained. Through the f value, it can be used to compare the composting effects of different compost raw materials, different composting parameters, etc., so as to uniformly evaluate different composting effects.

[0012] Therefore, the first aspect of the present invention provides a method for evaluating compost maturity.

[0013] Specifically, the method for evaluating compost maturity includes the following steps:

[0014] (1) Record the temperature curve during the composting process, with the time when the compost temperature reaches a plateau or the entire composting cycle as the calculation point; calculate the total heat generated from the start of composting to the calculation point, denoted as ΣQ.

[0015] (2) Measure the seed germination index, humus concentration, and organic matter concentration of the compost before composting and at the calculation point respectively; then calculate the differences in the seed germination index, humus concentration, and organic matter concentration, denoted as ΔGI, ΔHA, and ΔOM respectively.

[0016] (3) Calculate the organic fertilizer effect F, F = ΣQ × ΔGI × ΔHA / ΔOM;

[0017] Calculate the compost humus index f, f = F 计算点 / F 基准点 ;

[0018] F 基准点 is the F value calculated when the germination rate index of the seeds is greater than or equal to 70%;

[0019] Evaluate the degree of compost maturity according to the f value.

[0020] Preferably, the raw materials of the compost include at least one of sludge, animal manure, and agricultural waste.

[0021] Preferably, first mix the raw materials of the compost and water to obtain a compost material, and then place the compost material in a composting device for composting treatment to obtain compost.

[0022] Preferably, the water content of the compost material is 55 - 70%; more preferably, the water content of the compost material is 60 - 65.7%.

[0023] Preferably, the mixing also includes the process of adding a microbial agent.

[0024] Preferably, the microbial agent includes a thermophilic microbial agent.

[0025] Preferably, the composting treatment is carried out in a static composting manner.

[0026] Preferably, during the composting treatment, air is blown into the compost material; more preferably, the air blowing adopts an intermittent air blowing mode.

[0027] Preferably, electric field-assisted composting is also adopted during the composting treatment.

[0028] Preferably, in step (1), when a temperature plateau appears in the compost, the time point when the plateau appears is used as the calculation point; when no temperature plateau appears during the entire composting cycle, the entire composting cycle is used as the calculation point.

[0029] Preferably, in step (2), the germination rate index of the seeds is tested by the method in the organic fertilizer standard NY / T 525 - 2021.

[0030] Preferably, when the f is greater than or equal to 1, the compost is mature.

[0031] The second aspect of the present invention provides an application of the method for evaluating the maturity of the compost according to the first aspect of the present invention in composting.

[0032] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are as follows:

[0033] (1) By calculating the organic fertilizer effect F that can be generated by the unit of organic matter available to microorganisms during the composting process at a specific calculation point 计算点According to the organic fertilizer standard, when the GI is greater than or equal to 70%, the compost reaches the maturity standard. Taking this as the reference point, when the GI is greater than or equal to 70%, calculate the organic fertilizer effect F that can be produced by the unit of organic matter available to microorganisms during the composting process. 基准点 Furthermore, the f value is obtained. Through the f value, it can be used to compare the composting effects of different composting raw materials, different composting parameters, etc., so as to uniformly evaluate different composting effects.

[0034] (2) The evaluation method for compost maturity of the present invention combines physical, chemical, and biological indicators, and has the characteristic of comprehensiveness. Among them, the selected temperature stable point can reflect the degree of oxidation and decomposition of organic matter by compost microorganisms. The calculated total heat reflects the physical index of compost, and the selected GI reflects the biological index of compost.

[0035] (3) Each index of the present invention is relatively simple to measure, without the need for large-scale instruments, and can be quickly measured on-site, with the advantages of simple operation and low cost.

[0036] (4) The evaluation method of the present invention can compare the composting effects of different materials and different processes, and has the characteristics of applicability and practicality. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a change curve graph of temperature, organic matter concentration, humus concentration, and seed germination rate index during the composting process of Example 1 of the present invention;

[0038] Figure 2 It is a change curve graph of temperature, organic matter concentration, humus concentration, and seed germination rate index during the composting process of Example 2 of the present invention;

[0039] Figure 3 It is a change curve graph of temperature, organic matter concentration, humus concentration, and seed germination rate index during the composting process of Example 3 of the present invention;

[0040] Figure 4 It is a change curve graph of temperature, organic matter concentration, humus concentration, and seed germination rate index during the composting process of Example 4 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0041] In order to make those skilled in the art more clearly understand the technical solutions described in the present invention, the following examples are listed for illustration. It should be noted that the following examples do not limit the scope of protection required by the present invention.

[0042] In the following examples, the raw materials, reagents, or devices used can be obtained from conventional commercial channels or can be obtained by existing known methods without special instructions.

[0043] Example 1

[0044] A method for evaluating the maturity of compost, comprising the following steps:

[0045] (1) Compost raw materials and their ratios: Using the sludge from a municipal treatment plant as the main compost material, straw as the auxiliary material, the mass ratio of sludge to straw is 7:2, and the addition amount of the returned material (compost matured material) is 0.14% of the mass of the sludge. The total mass of the sludge, straw, and returned material is 120 kg; After mixing the above raw materials, 5 kg of water is added, stirred evenly to obtain the compost raw materials with a moisture content of 60%; The evenly stirred compost raw materials are added to a composting device for composting treatment;

[0046] Among them, the compost reactor of the composting device is made of polystyrene foam board, and the thickness of the polystyrene foam board is 10 cm. Specifically, the compost reactor is a cuboid structure surrounded by four polystyrene foam boards. The space surrounded by the four polystyrene foam boards is for the compost raw materials, and the length × width × height of the compost reactor is 50 cm × 60 cm × 100 cm;

[0047] (2) Parameter design: Adopt static composting, and the aeration adopts an intermittent aeration mode, aerating for 15 minutes and stopping for 45 minutes, and so on in cycles. The aeration volume is 1.5 L / min·kg dry weight of the material;

[0048] (3) Calculation of the compost maturity index: According to the formula of the present invention, calculate the f value, and the specific calculation process is as follows:

[0049] (a) Select the entire composting cycle (the composting cycle is 25 days) as the calculation point, calculate the total heat generated from the start of composting to the calculation point, and record it as ΣQ;

[0050] (b) Measure the GIs before and after composting treatment (i.e., before composting and at the calculation point) as 59.33% and 130.37% respectively, calculate the difference in GI, and record it as ΔGI;

[0051] (c) Measure the humus concentrations before and after composting treatment as 11.6 g / kg and 19.08 g / kg respectively, calculate the difference in humus concentration, and record it as ΔHA;

[0052] (d) Measure the organic matter concentrations before and after composting treatment as 47.86 g / kg and 24.16 g / kg respectively, calculate the difference in organic matter concentration, and record it as ΔOM;

[0053] (e) According to the formula F = ΣQ×ΔGI×ΔHA / ΔOM, calculate the F value; And according to the composting standard, when the GI is greater than or equal to 70%, the compost has reached the maturity standard. Therefore, select the 6th day as the calculation reference point, and use the organic matter concentration, humus concentration, and GI on this day as the reference point to calculate the F value of the reference point; And calculate the f value;

[0054] (f) Evaluate the degree of compost maturity and composting effect based on the f value.

[0055] In Example 1, the change curves of temperature, organic matter concentration, humus concentration, and seed germination rate index during the composting process are as Figure 1 shown. Among them, Figure 1 Figures (A)-(D) in

[0056] The calculated values of each index (ΣQ, ΔGI, ΔHA, ΔOM) during the composting process in Example 1 are shown in Table 1, where ΣQ is Figure 1 the area enclosed by the temperature curve in Figure (A) in

[0057] Example 2

[0058] The difference between Example 2 and Example 1 is only that Example 2 is aerobic composting of chicken manure, that is, the urban treatment plant sludge in Example 1 is replaced with an equal amount of chicken manure as the main composting material, and the others are the same as Example 1.

[0059] The calculation process of the f value in Example 2 is as follows:

[0060] (a) Select the entire composting cycle as the calculation point, calculate the total heat generated from the start of composting to the calculation point, and denote it as ΣQ;

[0061] (b) Measure the GIs before and after composting treatment as 59.4% and 157.41% respectively, calculate the difference in GI, and denote it as ΔGI;

[0062] (c) Measure the humus concentrations before and after composting treatment as 10.4 g / kg and 24.88 g / kg respectively, calculate the difference in humus concentration, and denote it as ΔHA;

[0063] (d) Measure the organic matter concentrations before and after composting treatment as 48.3 g / kg and 25.7 g / kg respectively, calculate the difference in organic matter concentration, and denote it as ΔOM;

[0064] (e) According to the formula F = ΣQ × ΔGI × ΔHA / ΔOM, calculate the F value, and according to the composting standard, when the GI is greater than or equal to 70%, the compost has reached the maturity standard. Therefore, select the 6th day as the calculation reference point, and use the organic matter concentration, humus concentration, and GI on that day as the reference point to calculate the F value of the reference point; and calculate the f value;

[0065] (f) Evaluate the degree of compost maturity and composting effect based on the f value.

[0066] In Example 2, the change curves of temperature, organic matter concentration, humus concentration, and seed germination rate index during the composting process are as Figure 2As shown in the figure. Among them, Figure 2 Figures (A)-(D) in Figure 2 are respectively the change curve graphs of temperature, organic matter concentration, humus concentration, and seed germination rate index.

[0067] The calculated values of each index (ΣQ, ΔGI, ΔHA, ΔOM) during the composting process in Example 2 are shown in Table 1, where ΣQ is Figure 2 the area enclosed by the temperature curve in Figure (A) in Figure 2 and the x-axis.

[0068] Example 3

[0069] Example 3 adopts an ultra-high temperature composting process with the addition of a microbial agent. At the same time, the thermophilic microbial agent Parageobacillus toebii is added, and the addition amount of the microbial agent is 2L, and the viable bacteria count ≥ 5×10 7 CFU / g; the culture conditions of the microbial agent are: constant temperature culture at 55°C, the culture medium is LB medium, and the culture time is 2 days; the raw material composition of the compost is: 70 kg of pig manure, 10 kg of mushroom residue, 10 kg of rice husk, 2 kg of microbial agent; 15 kg of returned material; after mixing the above raw materials, 5 kg of water is added and stirred evenly to obtain the compost raw material, and the moisture content of the compost raw material is 60% and the carbon-nitrogen ratio is 27. The compost pile is passed through a small air-blowing device, and air is introduced from the bottom. The aeration mode is to blow air for 0.5 h and stop for 1 h, and so on in a cycle; the power of the air-blowing pump is 15 w, and the ventilation volume is 3 L / min; other conditions are the same as in Example 1.

[0070] The calculation process of the f value in Example 3 is as follows:

[0071] (a) Select the entire composting cycle as the calculation point, calculate the total heat from the start of composting to the calculation point, and record it as ΣQ;

[0072] (b) Measure the GIs before and after composting treatment to be 44.26% and 135.43% respectively, calculate the difference in GI, and record it as ΔGI;

[0073] (c) Measure the humus concentrations before and after composting treatment to be 5.4 g / kg and 21.4 g / kg respectively, calculate the difference in humus concentration, and record it as ΔHA;

[0074] (d) Measure the organic matter concentrations before and after composting to be 29.68 g / kg and 11.54 g / kg respectively, calculate the difference in organic matter concentration, and record it as ΔOM;

[0075] (e) According to the formula F = ΣQ × ΔGI × ΔHA / ΔOM, calculate the F value, and according to the composting standard, when the GI is greater than or equal to 70%, the compost has reached the maturity standard. Therefore, select the 10th day as the calculation reference point, and use the organic matter concentration, humus concentration, and GI on that day as the reference point to calculate the F value at the reference point; and calculate the f value;

[0076] (f) Evaluate the degree of compost maturity and composting effect based on the f value.

[0077] During the composting process of Example 3, the change curves of temperature, organic matter concentration, humus concentration, and seed germination rate index are as Figure 3 shown. Among them, Figure 3 Figures (A)-(D) in it are the change curve graphs of temperature, organic matter concentration, humus concentration, and seed germination rate index respectively.

[0078] The calculated values of each index (ΣQ, ΔGI, ΔHA, ΔOM) during the composting process of Example 3 are shown in Table 1, where ΣQ is Figure 3 the area enclosed by the temperature curve in Figure (A) in it and the x-axis.

[0079] Example 4

[0080] In Example 4, the electro-assisted aerobic composting process is adopted. The same reactor as in Example 1 is used, and the ordinary aerobic composting process is replaced with the electro-assisted aerobic composting process.

[0081] The raw materials for composting are composed of: 70 kg of pig manure, 10 kg of mushroom residue, 10 kg of rice husk, and 15 kg of recycled material; after mixing the above raw materials, 5 kg of water is added and stirred evenly to obtain the composting raw materials. The water content of the composting raw materials is 60% and the carbon-nitrogen ratio is 27. Electrodes are placed on the left and right opposite directions of the reactor respectively. The material is stainless steel plate with a specification of 50×80 cm, and the power supply is set to 5V (50Hz) at both ends of the composting reactor. The compost pile is aerated through a small blower device, and the air enters from the bottom. The aeration mode is to blow air for 0.5 h and stop for 1 h, and so on in a cycle; the power of the air blower pump is 15 w and the ventilation volume is 3 L / min; other conditions are the same as in Example 1.

[0082] The calculation process of the f value in Example 4 is as follows:

[0083] (a) After 40 days of composting, the temperature of the compost pile is still decreasing; considering the temperature decrease, it indicates that the organic matter in the compost pile is still being utilized by microorganisms and releasing heat outward. The entire composting cycle is selected as the heat calculation cycle and used as the calculation point to calculate the total heat generated from the start of composting to the calculation point, denoted as ΣQ;

[0084] (b) The GIs before and after composting treatment are measured to be 12.36% and 140.95% respectively, and the difference in GI is calculated, denoted as ΔGI;

[0085] (c) The humus concentrations before and after composting treatment are measured to be 10.33 g / kg and 24.82 g / kg respectively, and the difference in humus concentration is calculated, denoted as ΔHA;

[0086] (d) The organic matter concentrations before and after composting were measured as 65 g / kg and 40.8 g / kg respectively, and the difference in organic matter concentration was calculated and denoted as ΔOM;

[0087] (e) According to the formula F = ΣQ × ΔGI × ΔHA / ΔOM, the value of F was calculated. According to the composting standard, when GI is greater than or equal to 70%, the compost has reached the maturity standard. Therefore, the 12th day was selected as the calculation reference point, and the organic matter concentration, humus concentration, and GI on that day were used as the reference point to calculate the F value at the reference point; and the f value was calculated;

[0088] (f) Based on the f value, the maturity degree and composting effect of the compost were evaluated.

[0089] In Example 4, the change curves of temperature, organic matter concentration, humus concentration, and seed germination rate index during composting are as Figure 4 shown. Among them, Figure 4 Figures (A)-(D) in it are the change curves of temperature, organic matter concentration, humus concentration, and seed germination rate index respectively.

[0090] The calculated values of each index (ΣQ, ΔGI, ΔHA, ΔOM) during the composting process of Example 1 are shown in Table 1, where ΣQ is Figure 4 the area enclosed by the temperature curve in Figure (A) in it and the x-axis.

[0091] Comparative Example 1

[0092] Comparative Example 1 used the same raw materials and operating parameters as Example 1. The change curves of temperature, organic matter concentration, humus concentration, and seed germination rate index during the composting process of Comparative Example 1 were the same as those of Example 1. The only difference was the evaluation method of compost maturity. Comparative Example 1 used the conventional compost maturity evaluation method, with GI as the compost maturity evaluation index and GI greater than or equal to 70% as the evaluation index, without calculating the values of other parameters.

[0093] Comparative Example 2

[0094] Comparative Example 2 used the same raw materials and operating parameters as Example 2. The change curves of temperature, organic matter concentration, humus concentration, and seed germination rate index during the composting process of Comparative Example 2 were the same as those of Example 2. The only difference was the evaluation method of compost maturity. Comparative Example 2 used ΣQ × ΔGI as the compost maturity evaluation index, without considering ΔHA and ΔOM, that is, F = ΣQ × ΔGI.

[0095] Comparative Example 3

[0096] Comparative Example 3 used the same raw materials and operating parameters as Example 3. During the composting process of Comparative Example 3, the change curves of temperature, organic matter concentration, humus concentration, and seed germination rate index were the same as those of Example 3. The only difference was the evaluation method for compost maturity. Comparative Example 3 used ΣQ×ΔGI×ΔHA as the evaluation index for compost maturity, without considering ΔOM, that is, F = ΣQ×ΔGI×ΔHA.

[0097] Comparative Example 4

[0098] Comparative Example 4 used the same raw materials and operating parameters as Example 4. During the composting process of Comparative Example 4, the change curves of temperature, organic matter concentration, humus concentration, and seed germination rate index were the same as those of Example 4. The only difference was the evaluation method for compost maturity. Comparative Example 4 used ΔGI×ΔHA as the evaluation index for compost maturity, without considering ΣQ and ΔOM, that is, F = ΔGI×ΔHA.

[0099] Table 1: Calculated values of each index in Examples 1 - 4 and Comparative Examples 1 - 4 ("-" indicates not calculated)

[0100]

[0101] In addition, according to the organic fertilizer standard, when GI is greater than or equal to 70%, the compost reaches the maturity standard; taking the compost raw materials of Examples 1 - 4 as an example, using the same composting process as Examples 1 - 4 respectively, samples corresponding to the number of days when GI is greater than or equal to 70% are taken, and total organic carbon (TOC), temperature, HA (humus), and odor are measured. The measurement methods are the methods specified by the standard.

[0102] The traditional evaluation method using a single index was used to evaluate the compost maturity of Examples 1 - 4, and the index parameters are shown in Table 2.

[0103] Table 2: Index parameters when evaluating the compost of Examples 1 - 4 using the traditional evaluation method with a single index

[0104]

[0105]

[0106] As can be seen from Tables 1 and 2, (1) for the comparison of composting effects within the same process, such as Example 1 and Example 2, both use the same process and different raw materials for composting treatment, and on the 6th day, the GI of the compost samples is greater than 70%, meeting the requirements of the compost maturity standard. However, when evaluating using a single index in the traditional evaluation method, the composting effects of the two raw materials cannot be evaluated. Because when evaluating the compost maturity effect using the traditional evaluation method, there are certain contradictions between different indexes. For example, according to the standard requirements, when the compost GI is greater than or equal to 70%, it can be considered that the compost is mature. However, at this time, the temperatures of the composts in the four examples are all in the high-temperature period, and the compost pile is still in a state of generating a large amount of heat, and the materials are far from reaching a stable state. When using the evaluation method of the present invention, the f value of Example 1 is 3.06, and the f value of Example 2 is 1.32. The f value of Example 1 is significantly higher than the f value of Example 2, indicating that the composting effect of Example 1 is better than that of Example 2.

[0107] (2) For the comparison of composting effects between different processes, such as Example 3 and Example 4, Example 4 and Example 3 use different composting processes. Example 3 uses the microbial agent composting process, and Example 4 uses the alternating current-assisted composting process. The compost of Example 3 reached a GI of 90% on the 10th day, and the compost of Example 4 reached a GI of 93% on the 12th day. If the traditional evaluation method is used, such as evaluating using a single seed germination rate index, the composts treated by these two processes are both mature, and it is difficult to compare the advantages and disadvantages of the two processes. When using the evaluation method of the present invention, the f value of the composting process of Example 3 is 7.82, and the f value of the composting process of Example 4 is 8.68. The f value of Example 4 is significantly higher than the f value of Example 3, indicating that the composting effect of the alternating current-assisted composting process is better than that of the microbial agent composting process.

[0108] (3) Comparison of different maturity formulas: Comparative Example 2 uses ΣQ and ΔGI as evaluation indicators, while Comparative Example 3 uses ΣQ, ΔGI, and ΔHA as evaluation indicators. The humus production and the consumed organic matter are not taken into account, resulting in a large f value. Organic matter with different degradation difficulties cannot be distinguished. For example, Example 2 is the effect produced by consuming 1 part of organic matter, while Comparative Example 2 is the effect produced by consuming 22.6 parts of organic matter; Example 3 is the effect produced by consuming 1 part of organic matter, while Comparative Example 3 is the effect produced by consuming 18.14 parts of organic matter. Comparative Example 4 uses ΔGI and ΔHA, without considering heat and consumed organic matter. During the composting process of Comparative Examples 3 and 4, although GI has reached the organic fertilizer standard (GI is greater than or equal to 70%) during the high temperature period of composting, its temperature is still high and has been in a downward process. There are still a large number of organic matter that have not been oxidized and decomposed. If the compost product at this time is used as fertilizer for plants, it will cause the "root burn" phenomenon, which is not conducive to plant growth.

[0109] (4) Comparison between single index and multiple indexes (as shown in Table 2). When the traditional evaluation method of single index is used to evaluate the compost maturity, there are certain contradictions between different indexes. For example, according to the standard requirements, when the compost GI is greater than or equal to 70%, the compost can be considered to be mature. However, when the traditional single index is used for evaluation, the temperature of the composts in Examples 1-4 is still in the high temperature period, the pile is still in a state of generating a large amount of heat, and the material is far from reaching a stable state. Because the single GI only reflects the biological index, it cannot well reflect the compost maturity.

[0110] In summary, the present invention comprehensively considers various evaluation indicators and calculates the organic fertilizer effect F that can be generated by a unit of organic matter that can be utilized by microorganisms during the composting process at a specific calculation point. 计算点 According to the organic fertilizer standard, when GI is greater than or equal to 70%, the compost reaches the maturity standard, and based on this as the benchmark, the organic fertilizer effect F that can be produced by the unit organic matter that can be used by microorganisms during the composting process when GI is greater than or equal to 70% is calculated. 基准点 , and then get the f value. Through the f value, the composting effects of different composting materials, different composting parameters, etc. can be compared, so that the maturity effects of different composts can be uniformly evaluated.

[0111] The above embodiments are only used to illustrate the technical solution of the present invention rather than to limit the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the essence and scope of the technical solution of the present invention.

Claims

1. A method for evaluating compost maturity, characterized in that: The following steps are involved: (1) Record the temperature curve during the composting process, and take the time when the compost temperature reaches a plateau or the entire composting cycle as the calculation point; calculate the total heat generated from the start of composting to the calculation point, recorded as ΣQ; (2) measuring the seed germination rate index, humus concentration and organic matter concentration of the compost before composting and at the calculation point respectively; then calculating the difference in the seed germination rate index, the difference in the humus concentration and the difference in the organic matter concentration, which are recorded as ΔGI, ΔHA and ΔOM respectively; (3) Calculate the organic fertilizer effect F, F = ΣQ × ΔGI × ΔHA / ΔOM; Calculate the compost humification index f, f = F 计算点 / F 基准点 ; F 基准点 is the F value calculated when the seed germination rate index is greater than or equal to 70%; The maturity of the compost is evaluated based on the f value.

2. The evaluation method according to claim 1, characterized in that: The raw material of the compost includes at least one of sludge, animal excrement and agricultural waste.

3. The evaluation method according to claim 2, characterized in that: Firstly, the raw materials of the composting are mixed with water to obtain composting materials, and then the composting materials are placed in a composting device for composting treatment to obtain compost.

4. The evaluation method according to claim 3, characterized in that: The moisture content of the compost material is 55-70%.

5. The evaluation method according to claim 3, characterized in that: The mixing also includes a process of adding a bacterial agent; and / or, during the composting process, aeration is performed into the compost material.

6. The evaluation method according to claim 5, characterized in that: The composting process also includes using electric field to assist composting.

7. The evaluation method according to claim 1, characterized in that: In step (1), when the compost temperature reaches a plateau, the time point at which the plateau appears is used as the calculation point; when the compost temperature does not reach a plateau during the entire composting period, the entire composting period is used as the calculation point.

8. The evaluation method according to claim 1, characterized in that: In step (2), the seed germination rate index is tested using the method in the organic fertilizer standard NY / T 525-2021.

9. The evaluation method according to claim 1, characterized in that: When f is greater than or equal to 1, the compost is mature.

10. Use of the evaluation method according to any one of claims 1 to 9 in composting.

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