Method for heat-activated peroxide enhanced compost humification synergistic gas emission reduction and tetracycline degradation

Abstract

The invention discloses a method for enhancing compost humification synergistic gas emission reduction and tetracycline degradation through thermal activation peroxide, and relates to the technical field of compost. The method comprises the following steps: mixing livestock and poultry manure and 1-3cm crop straws according to a dry weight ratio of (1-3): 1, and adjusting the carbon-nitrogen ratio to (20-30): 1 to complete raw material pretreatment; when the temperature of the pile body is 25-35 DEG C, peroxide (hydrogen peroxide, peracetic acid or potassium persulfate) is sprayed and mixed uniformly in the form of an aqueous solution, the addition amount is 0.125-1.25% of the dry weight of the raw materials, the moisture content of the pile body is controlled to be 55-75%, and continuous or intermittent ventilation composting is carried out at the speed of 0.2-1.0 m < 3 > h <-1 >. According to the method, the peroxide is activated by utilizing self-produced heat of compost, external energy sources and chemical activators are not needed, triple effects of compost humification improvement, ammonia gas and greenhouse gas emission reduction and tetracycline degradation are realized, and the method is green, environment-friendly, low in cost and suitable for organic solid waste treatment.

Description

Technical Field

[0001] This invention relates to the field of composting technology, specifically to a method for thermally activated peroxide-enhanced composting and humification, synergistic gas emission reduction, and tetracycline degradation. Background Technology

[0002] Agricultural waste such as straw and livestock manure has become a significant source of agricultural non-point source pollution. However, the current common methods for disposing of straw and livestock manure are landfilling or incineration, which not only waste resources but also easily cause secondary pollution to the environment. Aerobic composting is considered an economical, environmentally friendly, and sustainable way to harmlessly treat and utilize agricultural waste. It mainly promotes the biochemical process of converting biodegradable organic matter into stable humus through aerobic microorganisms, forming nutrient-rich and stable compost products. However, due to the lack of microenvironmental control technology during composting and the disordered mineralization of organic matter, aerobic fermentation composting suffers from common problems such as high greenhouse gas emissions, high environmental risks from emerging pollutants, and low humification levels.

[0003] Advanced oxidation processes (AOPs) hold promise for solving the aforementioned challenges. AOPs primarily generate highly oxidizing reactive species through physical or chemical means, often used to break down the structure of organic compounds and mineralize them. Due to their effectiveness in removing recalcitrant organic pollutants, they are attracting increasing attention from researchers. Applying AOPs to composting could potentially address the difficulties faced by traditional composting methods. AOPs require activation to be effective; common activation pathways include thermal activation, ultraviolet activation, transition metal activation, ultrasonic activation, and alkaline activation. Thermal activation, as an energy-enhancing method, avoids secondary pollution caused by the introduction of other ions because it does not require the addition of other chemical substances, aligning with the principles of green and sustainable development. However, its drawback lies in its requirement for continuous energy input and high energy consumption, limiting its large-scale application. Composting, on the other hand, is a process of microbial decomposition of organic matter, continuously releasing heat, which perfectly fills the energy gap left by thermal activation. Thermally activated peroxides not only promote the destruction of lignin structure in compost materials, enhance the accessibility of cellulase, and increase the degradation rate of lignocellulose, but also generate more humic precursors (phenols, quinones, aliphatic compounds, etc.) and typical humic acid core frameworks, thereby promoting humification. With the generation of more stable macromolecular humic substances, the content of easily degradable organic matter in the compost pile is reduced, which helps in the fixation of carbon and nitrogen elements, and has a positive effect on gas emission reduction during composting. The active species generated by thermal activation also have a certain removal effect on antibiotics in feces, helping to reduce the ecological risks of the product. Currently, there is no method to simultaneously achieve rapid composting, synergistic reduction of ammonia and greenhouse gases during composting, and efficient degradation of tetracycline. Combining self-generated heat from composting with thermally activated peroxides may be an effective solution. Therefore, this invention utilizes self-generated thermally activated peroxides from composting to develop a technology for synergistic gas emission reduction and tetracycline degradation during composting humification, achieving the sustainable green development goal of aerobic composting technology.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Summary of the Invention

[0005] The purpose of this invention is to provide a method that can simultaneously enhance composting humification, gas emission reduction, and tetracycline degradation. By using thermally activated peroxides, it achieves rapid composting, synergistic emission reduction of ammonia and greenhouse gases during composting, and efficient degradation of tetracycline.

[0006] To achieve the above objectives, this invention provides a method for synergistic gas emission reduction and tetracycline degradation through thermally activated peroxide-enhanced composting and humification, comprising the following steps: (1) Pretreatment of compost raw materials: Mix livestock and poultry manure and crop straw at a dry weight ratio of 1~3:1, and adjust the carbon-nitrogen ratio of compost raw materials to 20~30:1; (2) Peroxide addition: During the composting process, a peroxide solution is added to the compost pile. The peroxide is selected from at least one of peracetic acid, potassium persulfate or hydrogen peroxide, and the amount added is 0.125% to 1.25% of the dry weight of the compost raw materials. (3) Thermal activation reaction: The peroxide is thermally activated by the self-generated heat of the pile body at a temperature of 25~35°C; (4) Composting: Maintain the moisture content of the compost pile at 55%~75% and the aeration rate at 0.2~1.0 m. 3 h -1 The composting frequency is 1-2 times per day, and the composting cycle is 10-30 days.

[0007] Preferably, the above-mentioned livestock and poultry manure is at least one of chicken manure, pig manure or cow manure, and the crop straw is at least one of wheat straw, corn straw or rice straw, with a straw length of 1 to 3 cm.

[0008] Preferably, the peroxide is peracetic acid, and its addition amount is 0.5% to 0.75% of the dry weight of the compost raw material.

[0009] Preferably, the peroxide is potassium persulfate, and its addition amount is 0.75% to 1.25% of the dry weight of the compost raw material.

[0010] Preferably, the peroxide is hydrogen peroxide, and its addition amount is 0.125% to 0.5% of the dry weight of the compost raw material.

[0011] Preferably, the peroxide is added at the initial stage of composting or during the heating period, and more preferably, the temperature of the compost pile is 25~35℃.

[0012] The method provided by this invention can be used to achieve a reduction of greenhouse gas emissions by 10% to 30%, ammonia emissions by 10% to 50%, and a tetracycline degradation rate of 70% to 98%; wherein the greenhouse gases include CO2, N2O, and CH4.

[0013] The method provided by this invention can be used to improve the degree of composting humification, increasing the ratio of humic acid (HA) to fulvic acid (FA) to 1.5-2.0.

[0014] The method provided by this invention can be used for composting agricultural waste, promoting humification, reducing greenhouse gas and ammonia emissions, and degrading antibiotics. The agricultural waste includes livestock and poultry manure and straw.

[0015] The present invention has the following advantages: This invention utilizes the self-generated heat of composting to thermally activate peroxides, without introducing other substances and eliminating secondary pollution. Furthermore, it requires no external energy input, making it environmentally friendly and more eco-friendly. After thermal activation, the peroxides generate active free radicals, which can degrade pollutants in the compost and disrupt the lignocellulose structure of straw, promoting humification and thus fixing more carbon and nitrogen elements to achieve gas emission reduction.

[0016] This invention utilizes the self-generated heat of the compost pile to activate peroxides, eliminating the need for external energy or chemical activators. This achieves a triple effect: increased compost humification, synergistic reduction of ammonia and greenhouse gas emissions, and degradation of new pollutants, overcoming the limitations of existing technologies that can only optimize single or dual objectives. By utilizing the compost's own thermal energy for activation, external energy / reagent inputs are eliminated, reducing composting costs. It is applicable to organic solid waste treatment scenarios, enabling the resource utilization of organic solid waste while effectively controlling pollutants. It solves the problem of high ammonia and greenhouse gas emissions in traditional composting processes, making it a green and environmentally friendly method. Attached Figure Description

[0017] Figure 1 This is to simulate the temperature settings for auxiliary heating in composting.

[0018] Figure 2 Greenhouse gas emissions for each treatment group after adding PDS at different times.

[0019] Figure 3 The effects of different treatments on gas emission reduction, pollution reduction, and corrosion promotion are shown. Detailed Implementation

[0020] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] Note: Unless otherwise specified, the experimental methods in the following examples are conventional methods, performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Unless otherwise specified, the materials and reagents used in the following examples are commercially available.

[0022] Example 1 Chicken manure was used as the raw material for composting. Wheat straw was added as a conditioner at a dry weight ratio of 2:1 (chicken manure to straw) to adjust the carbon-to-nitrogen ratio (C / N) of the compost to 25:1. The materials were then mixed thoroughly. Tetracycline hydrochloride solution was then added to achieve a concentration of 50 mg / kg in the compost. -1The materials were then thoroughly mixed. Peracetic acid (PAA) solution was added by spraying at concentrations of 0%, 0.125%, 0.25%, 0.5%, and 0.75% of the dry weight of the compost raw materials. The recommended compost pile temperature at the time of addition was 25–35°C. The additive was then thoroughly mixed with the compost materials, resulting in a compost pile moisture content of approximately 65%. A simulated aerobic composting process was conducted for 10 days, using a compost treatment without additives as a control group. The aeration rate was 0.2–1.0 m³ / s. 3 h -1 The compost pile is turned every two days to ensure an aerobic environment. An auxiliary heating device is used to simulate the heat generation process during composting, with the temperature set as follows: Figure 1 As shown.

[0023] Compost samples were collected on days 1, 3, 5, 7, and 10. The collected samples were analyzed for physicochemical properties, humic content, and tetracycline content, with sampling times consistent with those for solid samples.

[0024] Ammonia was measured using Nessler's reagent colorimetric method during composting, while greenhouse gases (CO2, N2O, CH4) were measured using gas chromatography, with samples taken once daily.

[0025] Greenhouse gas emissions from each treatment group were measured, and the results are shown in Table 1. It can be seen that low levels of peracetic acid (PAA) promoted CH4 emissions. This is likely because the acetic acid present in PAA can directly serve as a substrate for methanogenesis, thus increasing CH4 emissions. In contrast, high-level PAA groups showed a significant decrease in CH4 emissions. Regarding CO2 emissions, the different PAA levels reduced emissions by -4.46%, 8.18%, 26.98%, and 5.19% compared to the control (CK), respectively. Calculations of the total greenhouse gas emission equivalent during composting revealed that a PAA addition ratio of 0.5% yielded the best greenhouse gas emission reduction effect, achieving a reduction rate of 26.35%.

[0026] Table 1. Effects of peracetic acid addition on greenhouse gas emissions during composting. Note: The global warming potentials used for CH4 and N2O are 28 and 265 times that of CO2, respectively, and the cumulative emissions of CH4 and N2O are converted into carbon dioxide equivalents (CO2-eq).

[0027] Example 2 Chicken manure was used as the raw material for composting. Wheat straw was added as a conditioner at a dry weight ratio of 2:1 (chicken manure to straw) to adjust the C / N ratio of the compost pile to 25:1. The materials were then mixed evenly. Tetracycline hydrochloride solution was then added to achieve a concentration of 50 mg / kg in the compost pile. -1The materials were then thoroughly mixed. Persulfate (PDS) solution was added by spraying at concentrations of 0%, 0.25%, 0.75%, and 1.25% of the dry weight of the compost raw materials. The recommended compost pile temperature at the time of addition was 25–35°C. The additive was then thoroughly mixed with the compost materials, resulting in a compost pile moisture content of approximately 65%. A simulated aerobic composting process was conducted for 10 days, using a compost treatment without additives as a control group. The aeration rate was 0.2–1.0 m³ / h. -1 The compost pile is turned every two days to ensure an aerobic environment. An auxiliary heating device is used to simulate the heat generation process during composting, with the temperature set as follows: Figure 1 As shown.

[0028] Compost samples were collected on days 1, 3, 5, 7, and 10. The collected samples were analyzed for physicochemical properties, humic content, and tetracycline content, with sampling times consistent with those for solid samples.

[0029] Ammonia was measured using Nessler's reagent colorimetric method during composting, while greenhouse gases (CO2, N2O, CH4) were measured using gas chromatography, with samples taken once daily.

[0030] Greenhouse gas emissions from each treatment group were measured, and the results are shown in Table 2. It can be seen that the addition of PDS reduced CH4 emissions, possibly because methanogens compete with sulfate for substrates, leading to a decrease in CH4 emissions. The addition of PDS reduced peak CO2 emissions. The addition of PDS effectively suppressed N2O produced in the initial stage of nitrification, while later, with the reduction of NO3... - The accumulation of nitrogen leads to an increase in N2O emissions from denitrification. Calculations of the total greenhouse gas emission equivalent during composting showed that a PDS addition ratio of 1.25% yielded the best greenhouse gas emission reduction effect, achieving a greenhouse gas emission reduction rate of 24.36%.

[0031] Table 2. Effects of potassium persulfate addition on greenhouse gas emissions during composting. Note: The global warming potentials used for CH4 and N2O are 28 and 265 times that of CO2, respectively, and the cumulative emissions of CH4 and N2O are converted into carbon dioxide equivalents (CO2-eq).

[0032] Example 3 Chicken manure was used as the raw material for composting. Wheat straw was added as a conditioner at a dry weight ratio of 2:1 (chicken manure to straw) to adjust the C / N ratio of the compost pile to 25:1. The materials were then mixed evenly. Tetracycline hydrochloride solution was then added to achieve a concentration of 50 mg / kg in the compost pile. -1The materials were then thoroughly mixed. Hydrogen peroxide solution was added by spraying at concentrations of 0%, 0.125%, 0.25%, and 0.5% of the dry weight of the compost raw materials. The recommended temperature for the compost pile during addition was 25–35°C. The additive was then thoroughly mixed with the compost materials, resulting in a pile moisture content of approximately 65%. A simulated aerobic composting process was conducted for 10 days, using a compost treatment without additives as a control group. The aeration rate was 0.2–1.0 m³ / h. -1 The compost pile is turned every two days to ensure an aerobic environment. An auxiliary heating device is used to simulate the heat generation process during composting, with the temperature set as follows: Figure 1 As shown.

[0033] Compost samples were collected on days 1, 3, 5, 7, and 10. The collected samples were analyzed for physicochemical properties, humic content, and tetracycline content, with sampling times consistent with those for solid samples.

[0034] Ammonia was measured using Nessler's reagent colorimetric method during composting, while greenhouse gases (CO2, N2O, CH4) were measured using gas chromatography, with samples taken once daily.

[0035] Greenhouse gas emissions from each treatment group were measured, and the results are shown in Table 3. CH4 emissions peaked during the warming phase of composting, at 0.22 mg / kg, 1.29 mg / kg, 0.35 mg / kg, and 0.97 mg / kg, respectively, and then increased again towards the end of the composting process. The addition of H2O2 promoted CH4 emissions. For CO2, the treatment groups reduced cumulative CO2 emissions by 16.01%, 15.36%, and 10.79%, respectively. N2O emissions were concentrated in the initial and maturation stages of composting. The addition of H2O2 enhanced N2O emissions in the initial stage and reduced N2O emissions in the maturation stage. Calculations showed that the best greenhouse gas emission reduction effect was achieved when the H2O2 addition ratio was 0.5%, resulting in a greenhouse gas emission reduction rate of 10.75%.

[0036] Table 3. Effects of hydrogen peroxide addition on greenhouse gas emissions during composting. Note: The global warming potentials used for CH4 and N2O are 28 and 265 times that of CO2, respectively, and the cumulative emissions of CH4 and N2O are converted into carbon dioxide equivalents (CO2-eq).

[0037] Example 4 Chicken manure was used as the raw material for composting. An appropriate amount of wheat straw was added as a conditioner at a dry weight ratio of 2:1 (chicken manure to straw), adjusting the C / N ratio of the compost pile to 25:1. The materials were then mixed thoroughly. Tetracycline hydrochloride solution was then added to achieve a concentration of 50 mg / kg in the compost pile. -1The materials were uniformly mixed, and the moisture content of the compost pile was approximately 65%. Persulfate (PDS) was added at 1.25% of the dry weight of the compost raw materials at the following stages: initial composting (D0, temperature 25–35°C); heating period (D1, temperature 45°C); high-temperature period (D3, temperature 55°C; D5, temperature 60°C); and maturation period (D7, temperature 50°C). The additive was thoroughly mixed with the compost materials. A simulated aerobic composting process was conducted for 10 days, with the untreated compost as the control (CK group). The aeration rate was 0.2–1.0 m³ / s. 3 h -1 The compost pile is turned every two days to ensure an aerobic environment. An auxiliary heating device is used to simulate the heat generation process during composting, with the temperature set as follows: Figure 1 As shown.

[0038] Greenhouse gases (CO2, N2O, CH4) during composting were measured using a gas chromatograph, with samples taken once daily.

[0039] Greenhouse gas emissions for each treatment group were measured, and the results are shown in [the table below]. Figure 2 As shown in the figure, adding PDS during the initial composting stage and the warming period effectively inhibits CH4 emissions, while adding PDS during the high-temperature period and the maturation period has no significant emission reduction effect. Adding PDS during the initial composting stage, the warming period, and the maturation period inhibits CO2 emissions. Adding PDS during the initial composting stage and the high-temperature period inhibits N2O emissions. With the change in composting time, when the composting system temperature reaches 45°C, the greenhouse gas emission rate of the treatment group with PDS added during the initial composting stage and the warming period is significantly lower than that of the control group, indicating that the heat generated by composting drives peroxide activation under this temperature condition. To control the total greenhouse gas emission equivalent during composting to the lowest level, PDS should be added in the early stage of composting (temperature 25-35°C). The greenhouse gas emission reduction rates of each treatment group relative to the control group (CK) are 14.32%, 5.38%, 3.37%, -9.94%, and 12.67%, respectively.

[0040] The effects of gas emission reduction, pollution reduction, and humification-promoting effects after composting in each treatment group of Examples 1-3 were measured, and the results are shown in the table below. Figure 3 As shown, where, Figure 3 (a), (b), (c), and (d) in the table represent the results of greenhouse gas emission equivalent reduction rate, NH3 emission reduction rate, Hufb ratio, and tetracycline degradation rate, respectively. (This is in conjunction with Tables 1-3 and...) Figure 2 , 3It can be seen that, with the primary goal of synergistic reduction of greenhouse gases and ammonia, while also considering efficient pollutant removal, the best-performing group was the one that added 0.5% PAA to the compost pile. This resulted in greenhouse gas and ammonia reduction rates of 26.35% and 47.35%, respectively, and a tetracycline degradation rate of 94.37%. However, this reduced the degree of humification of the compost pile. Using the Hufb ratio to measure the composting effect, the best-performing group was the one that added 0.5% H2O2 to the compost pile. This promoted the polymerization of small-molecule FA into large-molecule HA, achieving a Hufb ratio of 1.9 during a 10-day simulated composting period. However, the reduction effects on greenhouse gases and ammonia were relatively poor. To promote the triple effect of greenhouse gas and ammonia emission reduction, enhanced humification and pollutant removal, it is recommended to add 1.25% PDS at the initial stage of composting (temperature 25-35°C). This can achieve greenhouse gas and ammonia emission reduction rates of 24.36% and 12.14%, respectively, with a Hufb ratio of 1.84 and a tetracycline removal rate of 80.61%.

[0041] In summary, this invention provides a method for enhancing the synergistic gas emission reduction and tetracycline degradation through composting and humification, comprising the following: (1) Pretreatment of compost raw materials: Mix livestock and poultry manure and crop straw at a dry weight ratio of 1~3:1, and adjust the carbon-nitrogen ratio of compost raw materials to 20~30:1; the length of crop straw is 1~3 cm; (2) Thermally activated peroxide-enhanced aerobic composting: Peroxides, including hydrogen peroxide, peracetic acid, or sodium persulfate, are used as additives. The additive is added at a compost temperature of 25-35°C, with an addition ratio of 0.125%-1.25% of the dry weight of the compost raw materials. The additive is added in aqueous solution form by spraying and mixing. After addition, the moisture content of the compost pile is controlled at 55%-75%. Continuous or intermittent aeration is used during composting, with an aeration rate of 0.2-1.0 m / s. 3 h -1 .

[0042] Although the present invention has been described in detail through the preferred embodiments above, it should be understood that the above description should not be considered as a limitation of the present invention. Various modifications and substitutions to the present invention will be apparent to those skilled in the art after reading the above description. Therefore, the scope of protection of the present invention should be defined by the appended claims.

Claims

1. A method for synergistic gas emission reduction and tetracycline degradation through thermally activated peroxide-enhanced composting and humification, characterized in that, Includes the following steps: (1) Pretreatment of compost raw materials: Mix livestock and poultry manure and crop straw at a dry weight ratio of 1~3:1, and adjust the carbon-nitrogen ratio of compost raw materials to 20~30:1; (2) Peroxide addition: During the composting process, a peroxide solution is added to the compost pile. The peroxide is selected from at least one of peracetic acid, potassium persulfate or hydrogen peroxide, and the amount added is 0.125% to 1.25% of the dry weight of the compost raw materials. (3) Thermal activation reaction: The peroxide is thermally activated by the self-generated heat of the pile body at a temperature of 25~35°C; (4) Composting: Maintain the moisture content of the compost pile at 55%~75% and the aeration rate at 0.2~1.0 m. 3 h -1 The composting frequency is 1-2 times per day, and the composting cycle is 10-30 days.

2. The method according to claim 1, characterized in that, The livestock and poultry manure is at least one of chicken manure, pig manure or cow manure, and the crop straw is at least one of wheat straw, corn straw or rice straw, with a straw length of 1 to 3 cm.

3. The method according to claim 1, characterized in that, The peroxide is peracetic acid, and the amount added is 0.5% to 0.75% of the dry weight of the compost raw material.

4. The method according to claim 1, characterized in that, The peroxide is potassium persulfate, and the amount added is 0.75% to 1.25% of the dry weight of the compost raw material.

5. The method according to claim 1, characterized in that, The peroxide is hydrogen peroxide, and the amount added is 0.125% to 0.5% of the dry weight of the compost raw material.

6. The method according to claim 1, characterized in that, The peroxide is added at the initial stage of composting or during the heating period, when the compost temperature is 25-35℃.

7. The method according to claim 1, characterized in that, The method can be used to achieve greenhouse gas emission reduction of 10% to 30%, ammonia emission reduction of 10% to 50%, and tetracycline degradation rate of 70% to 98%; the greenhouse gases include CO2, N2O, and CH4.

8. The method according to claim 1, characterized in that, The method described above can be used to improve the degree of composting humification, thereby increasing the ratio of humic acid (HA) to fulvic acid (FA) to 1.5-2.

0.

9. The method according to any one of claims 1 to 8, characterized in that, The method can be used for composting agricultural waste, promoting humification, reducing greenhouse gas and ammonia emissions, and degrading antibiotics, wherein the agricultural waste includes livestock and poultry manure and straw.

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