Greenhouse gas and odor coordinated emission reduction and accelerated composting method and application

Abstract

This invention belongs to the field of composting technology, and specifically relates to a composting method and application for coordinated reduction of greenhouse gases and odors and accelerated composting. The composting method for coordinated reduction of greenhouse gases and odors and accelerated composting of this invention includes the following steps: (1) mixing composting raw materials with plant tannins to obtain compost material; (2) fermenting the compost material, turning the pile, and when the temperature of the compost material drops to room temperature and remains stable, the material is matured, completing the composting process. Plant tannins include at least one of bayberry tannin, larch tannin, oak tannin, vitex bark tannin, and chestnut tannin. This invention uses plant tannins as an additive and utilizes a fermentation process to allow microorganisms to react with the plant tannins, which to a certain extent inhibits the growth of anaerobic microorganisms and provides humic precursors to accelerate composting, thereby reducing odors and accelerating composting. This invention is simple and easy to implement, and plant tannins are widely available and inexpensive, enabling large-scale production and application.

Description

Technical Field

[0001] This invention belongs to the field of organic fertilizer technology, and specifically relates to a composting method and application that coordinates the reduction of greenhouse gas and odor emissions and accelerates composting. Background Technology

[0002] In recent years, with the continued rise in the market for Maotai-flavor liquor, the large-scale discharge of brewing wastewater has led to a rapid increase in the production of brewing sludge. Currently, brewing sludge in Maotai-flavor liquor production areas is mainly treated by incineration, which greatly hinders the expansion of Maotai-flavor liquor production capacity and the upgrading of the green industry. Aerobic composting technology is the most environmentally friendly way to achieve the harmless disposal of brewing sludge. However, the composting process, due to the presence of anaerobic microzones, generates a large amount of greenhouse gases and odors, which not only affects the quality of compost products but also causes serious environmental pollution and poses human health problems. In addition, traditional aerobic composting technology suffers from problems such as long composting cycles and incomplete conversion of organic matter.

[0003] Currently, the main approach to addressing issues such as odor and greenhouse gas emissions, as well as long composting cycles, in composting is to add exogenous substances. Some studies have disclosed methods to reduce greenhouse gas and ammonia emissions by adding ferrous sulfate and vermiculite; others have disclosed the use of coral sand to reduce nitrogen damage. However, these additives only offer advantages in reducing greenhouse gas emissions or accelerating composting; they cannot simultaneously achieve both. Furthermore, due to production costs and processing technology limitations, they cannot be widely applied to brewing sludge composting.

[0004] Therefore, there is an urgent need to provide a composting method that can reduce odor and greenhouse gas emissions while accelerating composting and shortening the composting cycle. Summary of the Invention

[0005] This invention aims to solve one or more technical problems existing in the prior art, and at least provide a beneficial alternative or create favorable conditions. This invention provides a composting method that can reduce odor and greenhouse gas emissions, while simultaneously accelerating composting and shortening the composting cycle.

[0006] The inventive concept of this invention: The plant tannin of this invention includes at least one of the following: bayberry tannin, larch tannin, oak tannin, vitex bark tannin, and chestnut tannin. This invention uses plant tannin as an additive and utilizes a fermentation process to allow microorganisms to react with the plant tannin. On the one hand, this can inhibit the growth of anaerobic microorganisms to a certain extent; on the other hand, it provides humic precursor substances that can accelerate composting, ultimately achieving coordinated reduction of odor and greenhouse gas emissions. At the same time, it can accelerate composting and shorten the composting cycle.

[0007] Therefore, a first aspect of the present invention provides a composting method for coordinated reduction of greenhouse gas and odor emissions and accelerated decomposition.

[0008] Specifically, the composting method for coordinated reduction of greenhouse gases and odors and accelerated decomposition includes the following steps:

[0009] (1) Mix the composting raw materials and plant tannins to obtain compost material;

[0010] (2) Ferment the compost material described in step (1), turn the pile, and when the temperature of the compost material drops to room temperature and remains stable, the compost material is matured and composting is completed.

[0011] The plant tannins include at least one of the following: bayberry tannin, larch tannin, rubber tannin, vitex bark tannin, and chestnut tannin.

[0012] Preferably, the composting raw materials include at least one of brewing sludge, distiller's grains, cellar mud, and sorghum straw.

[0013] Preferably, in step (1), the carbon-to-nitrogen ratio of the compost material is 22-33:1.

[0014] More preferably, in step (1), the carbon-to-nitrogen ratio of the compost material is 25-30:1.

[0015] Specifically, the nitrogen content of the material was determined using the Kjeldahl method; the organic carbon content of the material was determined using the potassium dichromate titration method (refer to NY 525-2021).

[0016] Preferably, in step (1), the moisture content of the compost material is 50-65%.

[0017] More preferably, in step (1), the moisture content of the compost material is 55-60%.

[0018] Preferably, in step (1), the mass ratio of the plant tannin to the composting raw material is (0.9-9):(90-130).

[0019] More preferably, in step (1), the mass ratio of the plant tannin to the composting raw material is (1-8):(100-120).

[0020] Preferably, in step (2), the fermentation is aerobic fermentation.

[0021] Preferably, the aerobic fermentation adopts an intermittent aeration method.

[0022] Preferably, the intermittent ventilation method is to aerate for 25-35 minutes and then stop for 35-35 minutes; more preferably, the intermittent ventilation method is to aerate for 27-33 minutes and then stop for 27-33 minutes; even more preferably, the intermittent ventilation method is to aerate for 30 minutes and then stop for 30 minutes.

[0023] Preferably, the intermittent ventilation method is to use a high-pressure blower to force ventilation and oxygen supply.

[0024] Preferably, the ventilation rate is 0.010-0.014 m³ / s. 3 / (Kg compost material * h).

[0025] More preferably, the ventilation rate is 0.011-0.013 m³ / h. 3 / (Kg compost material * h).

[0026] More preferably, the ventilation rate is 0.012 m³ / s. 3 / (Kg compost material * h).

[0027] Preferably, in step (2), turning the compost pile specifically involves monitoring the temperature of the compost material during the composting process and turning the compost pile when the temperature of the compost material drops.

[0028] Specifically, the temperature of the compost material is measured by using an engineering pointer thermometer to monitor the temperature of the compost material at three fixed points in the fermentation device every day.

[0029] Preferably, the temperature rises rapidly in the early stage of composting, with a turning interval of 1.5-4.5 days, while the temperature rises slowly in the later stage of composting, with a turning interval of 4.5-7.5 days.

[0030] More preferably, the turning interval is 2-4 days in the early stage of composting and 5-7 days in the later stage of composting.

[0031] Preferably, the composting cycle is 18-38 days.

[0032] More preferably, the composting cycle is 20-35 days.

[0033] The third aspect of the present invention provides an application of the composting method for coordinated reduction of greenhouse gases and odors and accelerated decomposition described in the first aspect of the present invention in the field of organic fertilizer.

[0034] Compared with the prior art, the beneficial effects of the technical solution provided by the present invention are as follows:

[0035] (1) Plant tannin is a chemical product extracted from plants. It contains rich tannins and other natural compounds. This invention uses plant tannins such as bayberry tannin, larch tannin, and oak tannin as additives and utilizes fermentation process to make microorganisms react with plant tannins. On the one hand, it can inhibit the growth of microorganisms, and on the other hand, it can promote and accelerate the composting process, achieve coordinated emission reduction of odor and greenhouse gases, and at the same time accelerate the composting process and shorten the composting cycle.

[0036] (2) The plant tannin additive material of the present invention has a wide range of sources and low price, which can reduce production costs and has good economic benefits.

[0037] (3) The preparation process of this invention is simple and easy to apply in large-scale production. Attached Figure Description

[0038] Figure 1 These are temperature change curves of compost materials during the composting process in Examples 1-3 and Comparative Example 1 of the present invention.

[0039] Figure 2 The cumulative CH4 emission curves for Examples 1-3 and Comparative Example 1 of this invention are shown below.

[0040] Figure 3 The cumulative N2O emission curves for Examples 1-3 and Comparative Example 1 of this invention are shown below.

[0041] Figure 4 This is a graph showing the cumulative NH3 emissions of Examples 1-3 and Comparative Example 1 of the present invention.

[0042] Figure 5 The cumulative H2S emission curves for Examples 1-3 and Comparative Example 1 of this invention are shown. Detailed Implementation

[0043] To enable those skilled in the art to more clearly understand the technical solutions described in this invention, the following embodiments are provided for illustration. It should be noted that the following embodiments do not constitute a limitation on the scope of protection claimed by this invention.

[0044] Unless otherwise specified, the raw materials, reagents or devices used in the following examples are available from conventional commercial sources or can be obtained by existing known methods.

[0045] Example 1

[0046] The composting raw materials consist of brewing sludge and sorghum straw (in a weight ratio of 17:3), with larch tannin as the additive, which accounts for 2% of the total weight of the compost.

[0047] A composting method for coordinated reduction of greenhouse gases and odors and accelerated decomposition includes the following steps:

[0048] (1) Mix brewing sludge, sorghum straw and larch tannin, stir evenly, and adjust the moisture content to 55% to obtain compost material;

[0049] (2) The compost material obtained in step (1) is transferred into a fermentation device for aerobic fermentation. A high-pressure blower is used for intermittent aeration, with an aeration period of 30 minutes followed by a 30-minute pause. The aeration rate is 0.012 m³ / min. 3 / (Kg compost material * h); The entire composting cycle is 35 days. For the first 20 days of composting, turn the pile every 2 days. For the 21st to 35th days after composting, turn the pile every 5 days until the temperature drops to room temperature and remains stable, the compost is fully decomposed, and the composting is completed.

[0050] At three fixed points in the fermentation unit, engineering pointer thermometers were used to monitor the temperature of the compost material during the composting process at regular intervals every day. The temperature changes of the compost material were as follows: Figure 1 .

[0051] Example 2

[0052] The only difference between Example 2 and Example 1 is that in Example 2, the amount of larch tannin added is 5% of the total weight of the compost; otherwise, it is the same as in Example 1. The temperature change of the compost material is as follows: Figure 1 As shown.

[0053] Example 3

[0054] The only difference between Example 3 and Example 1 is that in Example 3, the amount of larch tannin added is 8% of the total weight of the compost; otherwise, it is the same as in Example 1. The temperature change of the compost material is as follows: Figure 1 As shown.

[0055] Example 4

[0056] The composting materials consist of brewing sludge, distiller's grains, and sorghum straw (in a weight ratio of 17:2:3), and the additive is tannin from the bark of Vitex negundo, which is added at a rate of 4% of the total weight of the compost.

[0057] A composting method for coordinated reduction of greenhouse gases and odors and accelerated decomposition includes the following steps:

[0058] (1) Mix brewing sludge, lees, sorghum straw and tannin from the bark of the Vitex negundo tree, stir evenly, and adjust the moisture content to 60% to obtain compost material;

[0059] (2) The compost material is transferred to a fermentation device for aerobic fermentation, and intermittent aeration is carried out using a high-pressure blower with an aeration rate of 0.012 m³ / s. 3 / (Kg compost material*h); The entire composting cycle is 35 days. During the first 16 days of composting, the compost is turned over every 2 days. During the later stage of composting, the compost is turned over every 5 days. At 3 fixed points of the fermentation device, engineering pointer thermometers are used to monitor the temperature of the compost material every day until the temperature of the compost material approaches room temperature, the compost is mature, and the composting is completed.

[0060] Example 5

[0061] The only difference between Example 5 and Example 4 is that the amount of Vitex bark tannin added in Example 5 is 8% of the total weight of the compost, while the rest is the same as in Example 4.

[0062] Example 6

[0063] The composting raw materials consist of brewing sludge and sorghum straw (in a weight ratio of 17:3), with larch tannin as the additive, and the amount added is 5% of the total weight of the compost.

[0064] A composting method for coordinated reduction of greenhouse gases and odors and accelerated decomposition includes the following steps:

[0065] (1) Mix brewing sludge, sorghum straw and larch tannin, stir evenly, and adjust the moisture content to 60% to obtain compost material;

[0066] (2) The compost material is transferred to a fermentation device for aerobic fermentation, and intermittent aeration is carried out using a high-pressure blower with an aeration rate of 0.012 m³ / s. 3 / (kg compost material * h); The entire composting cycle is 35 days. During the first 20 days of composting, the compost is turned over every 2 days. During the later stage of composting, the compost is turned over every 5 days. At 3 fixed points of the fermentation device, engineering pointer thermometers are used to monitor the temperature of the compost material every day until the temperature of the compost material approaches room temperature, the compost is mature, and the composting is completed.

[0067] Example 7

[0068] The only difference between Example 7 and Example 6 is that the additive in Example 7 is bayberry tannin, and the amount added is 5% of the total weight of the compost. Otherwise, they are the same as in Example 6.

[0069] Example 8

[0070] The only difference between Example 8 and Example 6 is that the additive in Example 8 is tannin from Vitex negundo bark, and the amount added is 5% of the total weight of the compost. Otherwise, they are the same as in Example 6.

[0071] Comparative Example 1

[0072] The only difference between Comparative Example 1 and Example 1 is that Comparative Example 1 did not include larch tannin; otherwise, it was the same as Example 1. The temperature changes of the compost material were as follows: Figure 1 As shown.

[0073] Comparative Example 2

[0074] The only difference between Comparative Example 2 and Example 4 is that Comparative Example 2 did not add Vitex bark tannin; otherwise, it was the same as Example 4.

[0075] Comparative Example 3

[0076] The only difference between Comparative Example 3 and Example 6 is that Comparative Example 3 did not contain larch tannin; otherwise, they are the same as Example 6.

[0077] Performance testing

[0078] 1. Moisture content determination

[0079] The compost obtained in Examples 1-3 and Comparative Example 1 was dried at 105℃ for 12 hours. The weight of the compost before and after drying was measured to obtain the moisture content. Moisture content % = (weight of compost before drying - weight of compost after drying) / weight of compost before drying × 100%. The moisture content is shown in Table 1.

[0080] Table 1: Moisture content of compost obtained in Examples 1-3 and Comparative Example 1

[0081] Test Project Example 1 Example 2 Example 3 Comparative Example 1 Moisture content 39.6％ 36.5％ 35.5％ 42.8％

[0082] As shown in Table 1, the moisture content of the compost obtained by adding plant tannin in Examples 1-3 of the present invention is lower than that of the compost obtained without adding plant tannin.

[0083] 2. Determination of humic substances (HS), fulvic acid (FA), and humic acid (HA)

[0084] The compost from Examples 1-8 and Comparative Examples 1-3 was air-dried and used as compost samples. Each gram of air-dried compost sample was added to 10 mL of a mixed solution of 0.1 M NaOH and 0.1 M Na4P2O7·10H2O, centrifuged and filtered, and the filtrate was HS. Subsequently, 0.5 M HCl was added to adjust the pH to 7.0, filtered, and the pH was adjusted to below 2 with concentrated HCl and allowed to settle. The supernatant was FA, and the precipitate was HA. The HA was dissolved with alkali to obtain the HA solution. The organic carbon content in the HS solution, FA solution and HA solution was determined using a total organic carbon analyzer (TOC analyzer), which are the contents of HS, FA and HA. The results are shown in Table 2.

[0085] Table 2: Content of HS, FA and HA in compost of Examples 1-8 and Comparative Examples 1-3

[0086]

[0087] As shown in Table 2, compared with Comparative Example 1, the content of humic acid (HA) in Examples 1-3 of the present invention increased by 17.7%, 29.6%, and 38.3%, respectively; compared with Comparative Example 2, the content of humic acid (HA) in Examples 4-5 increased by 31.84% and 45.30%, respectively; compared with Comparative Example 3, the content of humic acid (HA) in Examples 6-8 increased by 44.84%, 52.91%, and 50.67%, respectively. This indicates that the present invention can accelerate composting and shorten the composting cycle by adding plant tannin.

[0088] 3. Cumulative emissions of CH4, N2O, NH3, and H2S

[0089] Organic glass cylindrical tubes were used to collect and measure the gases generated during the composting process of Examples 1-8 and Comparative Examples 1-3. Samples were collected every 3 days for the first 15 days and every 5 days thereafter. Each collection lasted 30 minutes. Three parallel samples were collected from each group, and the average value was calculated.

[0090] Greenhouse gases CH4 and N2O were detected using an Agilent gas chromatograph equipped with a flame ionization detector (FID) and an electron capture detector (ECD). Odor gases NH3 and H2S concentrations were measured using an online gas monitoring system, and their cumulative amounts throughout the composting period were calculated. Results are as follows: Figure 2-5 As shown, where Figure 2-5 The graphs show the cumulative emissions of CH4, N2O, NH3, and H2S for Examples 1-3 and Comparative Example 1, respectively.

[0091] Depend on Figure 2-5 As can be seen, compared with Comparative Example 1, the cumulative emissions of CH4 in Examples 1-3 decreased by 31.85%, 42.46%, and 44.88%, respectively; the cumulative emissions of N2O decreased by 41.68%, 46.40%, and 47.65%, respectively; the cumulative emissions of NH3 decreased by 49.15%, 58.64%, and 59.93%, respectively; and the cumulative emissions of H2S decreased by 94.10%, 94.11%, and 94.11%, respectively. This indicates that larch tannin effectively suppresses the emissions of greenhouse gases and odors.

[0092] In addition, compared with Comparative Example 2, the cumulative emissions of CH4 in Examples 4-5 were reduced by 45.62% and 48.98%, respectively; the cumulative emissions of N2O were reduced by 43.23% and 45.21%, respectively; the cumulative emissions of NH3 were reduced by 52.34% and 58.12%, respectively; and the cumulative emissions of H2S were reduced by 93.26% and 93.45%, respectively.

[0093] Compared with Comparative Example 3, the cumulative emissions of CH4 in Examples 6-8 decreased by 45.63%, 48.68%, and 47.65%, respectively; the cumulative emissions of N2O decreased by 47.23%, 48.35%, and 48.88%, respectively; the cumulative emissions of NH3 decreased by 60.12%, 58.91%, and 59.68%, respectively; and the cumulative emissions of H2S decreased by 94.65%, 94.55%, and 94.78%, respectively.

[0094] As can be seen from the cumulative emissions of CH4, N2O, NH3 and H2S mentioned above, adding plant tannin to compost raw materials can effectively suppress the emission of greenhouse gases and odors.

[0095] In summary, this invention uses plant tannins such as bayberry tannin, larch tannin, and oak tannin as additives, and utilizes a fermentation process to allow microorganisms to react with the plant tannins. This process inhibits the growth of anaerobic microorganisms to a certain extent and accelerates composting by providing precursors for humus, achieving a triple effect of reducing odor and accelerating composting. Furthermore, the composting method of this invention is simple and easy to implement, the additive materials are widely available and inexpensive, resulting in low costs and enabling large-scale production and application, thus offering good economic benefits.

[0096] The above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A composting method, characterized in that, Includes the following steps: (1) Mix the composting raw materials and plant tannins to obtain compost material; (2) Ferment the compost material described in step (1). When the temperature of the compost material drops to room temperature and remains stable, the compost material is matured and composting is completed. The plant tannins include at least one of the following: bayberry tannin, larch tannin, rubber tannin, vitex bark tannin, and chestnut tannin; The composting raw materials include at least one of brewing sludge, distiller's grains, cellar mud, and sorghum straw; In step (1), the mass ratio of the plant tannin to the composting raw material is (0.9-9):(90-130). In step (1), the carbon-to-nitrogen ratio of the compost material is (22-33):1; the moisture content of the compost material is 50-65%. In step (2), the fermentation is aerobic fermentation.

2. The composting method according to claim 1, characterized in that, The aerobic fermentation process employs an intermittent aeration method.

3. The composting method according to claim 1, characterized in that, In step (2), the compost pile is turned over during the fermentation process; specifically, the temperature of the compost material is monitored during the composting process, and the compost pile is turned over when the temperature of the compost material drops.

4. The composting method according to claim 1, characterized in that, The composting cycle is 18-38 days.

5. The application of the composting method according to any one of claims 1-4 in the field of organic fertilizer.

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