System for reducing ammonia emission in compost and producing nitrogen-rich organic fertilizer and use method thereof

Abstract

The invention belongs to the field of organic waste resource utilization, and particularly relates to a system for reducing ammonia emission in compost and producing a nitrogen-rich organic fertilizer and a use method of the system. Comprising a condenser pipe, a composting reactor main body, a gas flowmeter and an aeration pump, the condensation pipe is communicated with the top of the composting reactor main body; the composting reactor main body is connected with the gas flow meter; the gas flow meter is connected with the aeration pump; the method is low in operation cost, good in ammonia emission reduction effect and suitable for large-scale application, and the nitrogen content in compost products can be remarkably increased.

Description

Technical Field

[0001] The invention belongs to the field of resource utilization of organic waste, and particularly relates to a system for reducing ammonia emission in compost and producing nitrogen-rich organic fertilizer and a use method thereof. Background Art

[0002] Improper disposal of organic waste has always been a major challenge in the field of environmental protection. It not only leads to the decline of air quality and pollution of water resources, but also seriously damages the ecological balance of the soil. These wastes are difficult to decompose on their own in the natural environment, and often accumulate and release harmful substances, posing a long-term threat to the ecosystem. Composting, as an effective organic waste treatment technology, provides a feasible way to solve this problem by converting organic waste into nutrient-rich soil conditioners. The composting process can not only significantly reduce the amount of organic waste, but also effectively destroy the weed seeds and pathogens therein, thereby preventing them from further harming crops and ecosystems. More importantly, compost products can significantly improve the structure and function of the soil, enhance the soil's fertility and water retention capacity, thereby promoting the healthy growth of crops and increasing yields.

[0003] However, the problem of ammonia emissions generated during the composting process cannot be ignored. Since organic waste used as compost raw materials usually contains high nitrogen elements, these nitrogen elements will be converted into ammonia and released into the atmosphere under the action of microorganisms. Ammonia emissions will not only corrode composting equipment and aggravate air pollution problems, but may also enter the human body through the respiratory tract and cause damage to the human respiratory and immune systems. In addition, ammonia emissions will also lead to a decrease in the nitrogen content in the compost product, which in turn affects its fertilizer efficiency and application effect, and reduces the overall quality of the compost product.

[0004] At present, the emission of ammonia is mainly reduced by adjusting some key parameters in the composting process. For example, by accurately controlling the aeration rate, the oxygen supply inside the compost can be optimized, the respiration of microorganisms can be promoted, and the production of ammonia can be reduced. At the same time, regular turning of the compost and adjusting the stacking density can also help improve the ventilation conditions inside the compost, reduce the formation of anaerobic environment, and further reduce the emission of ammonia. However, due to the huge differences in the scale of composting production and the diversity of raw materials used, the optimization of these parameters is often difficult to achieve in actual operation, which limits the scope of its promotion and application. In addition to adjusting the composting parameters, adding exogenous substances is also regarded as an effective ammonia emission reduction strategy. In recent years, domestic and foreign scholars have conducted a lot of research in this field and explored the effects of various additives on ammonia emissions during composting. For example, CN117285387A discloses a method for adding synthetic bacterial flora; CN115672292A discloses a method for adding Fe-MOFs@biochar composite materials; CN105523804A discloses a method for adding modified biochar. However, these additives often have problems such as non-reusability and high cost, making it difficult to achieve large-scale application in compost production. Summary of the invention

[0005] In order to solve the problems of the prior art, the present invention provides a system for reducing ammonia emissions in compost and producing nitrogen-rich organic fertilizer and a method for using the system, which can significantly increase the nitrogen content in the compost product with low operating costs.

[0006] In order to achieve the above object, the present invention adopts the following technical solutions: In a first aspect, the present invention provides a system for reducing ammonia emissions in composting and producing nitrogen-rich organic fertilizer, comprising a condenser, a composting reactor body, a gas flow meter and an aeration pump; the condenser is connected to the top of the composting reactor body; the composting reactor body is connected to the gas flow meter; the gas flow meter is connected to the aeration pump.

[0007] Preferably, the composting reactor body comprises a base and a barrel body arranged on the base; a barrel cover is arranged on the top of the barrel body; and the barrel cover is connected to a condenser pipe.

[0008] Preferably, the interior of the barrel body is a cavity structure, and the cavity structure is connected to the condenser.

[0009] Preferably, the bottom of the barrel is connected to a gas flow meter through a pipeline.

[0010] Preferably, the gas flow meter and the aeration pump are connected through an aeration pipe.

[0011] Preferably, the condenser is a straight glass condenser.

[0012] In a second aspect, the present invention provides a method for using a system for reducing ammonia emissions in compost and producing nitrogen-rich organic fertilizer, comprising the following steps: The compost material is added into the cavity structure in the compost reactor body through the barrel cover for composting, the aeration pump is turned on, and the gas is transported to the compost reactor body through the aeration pipe for forced aeration, and the compost is turned when the compost temperature is greater than 50°C; when the compost temperature drops to the ambient temperature, the obtained compost is crushed, sieved and granulated to obtain nitrogen-rich organic fertilizer.

[0013] Preferably, the carbon-nitrogen ratio of the compost material is (20-30):1; and the moisture content of the compost material is 55%-65%.

[0014] Preferably, the aeration rate is 0.05-0.3 L min -1 kg -1 Dry weight.

[0015] Preferably, the frequency of turning the compost is 3 to 5 days / time.

[0016] Compared with the prior art, the present invention has the following beneficial effects: The present invention is used for composting and fermenting organic waste through a composting reactor body. A gas flow meter is used to monitor and record the gas flow discharged from the reactor, so as to understand the emission of gas in the reactor in real time and provide a basis for subsequent aeration treatment and ammonia recovery; an aeration pump is used to provide an appropriate amount of oxygen into the composting reactor body. The aeration action of the aeration pump can accelerate the metabolic activities of microorganisms in the reactor and promote the decomposition and conversion of organic matter. The condenser can lock ammonia in the composting reactor to reduce its volatilization. The ammonia locked in the reactor is further converted into organic nitrogen by microorganisms and retained in the compost, which significantly reduces the emission of ammonia in the compost and increases the nitrogen content of the compost product. The condenser only relies on air for condensation, does not consume additional electricity, has low operating costs, does not cause secondary pollution, and is suitable for large-scale applications. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 This is a schematic structural diagram of a system for reducing ammonia emission in compost and producing nitrogen-rich organic fertilizer according to the present invention; Figure 2(a) is a schematic diagram of the change of NH3 emission rate during the composting process of Example 1, Example 2 and Comparative Example 1; Figure 2 (b) is a schematic diagram of the cumulative NH3 emissions during the composting process of Example 1, Example 2 and Comparative Example 1; Figure 3 Schematic diagram of the changes in the total nitrogen, organic nitrogen and inorganic nitrogen contents in the compost products of Example 1, Example 2 and Comparative Example 1; Figure 4 Schematic diagram of the changes in the total nitrogen, organic nitrogen and inorganic nitrogen contents in the compost products of Example 3 and Comparative Example 2; Figure 5 Schematic diagram of the changes in the total nitrogen, organic nitrogen and inorganic nitrogen contents in the compost products of Example 4 and Comparative Example 3.

[0019] In the figure, 1. condenser; 2. composting reactor body; 201. barrel cover; 202. barrel body; 203. base; 3. gas flow meter; 4. aeration pump; 5. aeration pipe. DETAILED DESCRIPTION

[0020] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

[0021] The theories or mechanisms described and disclosed herein, whether correct or incorrect, should not limit the scope of the present invention in any way, that is, the present invention can be implemented without being limited by any specific theory or mechanism.

[0022] In this article, all features such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be considered to have included and specifically disclosed all possible secondary ranges and individual values ​​within the range (including integers and fractions).

[0023] In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0024] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0025] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0026] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0027] The first object of the present invention is to provide a system for reducing ammonia emission in composting and producing nitrogen-rich organic fertilizer, such as Figure 1 As shown, it includes a condenser 1, a composting reactor body 2, a gas flow meter 3 and an aeration pump 4; the condenser 1 is connected to the top of the composting reactor body 2; the composting reactor body 2 is connected to the gas flow meter 3; the gas flow meter 3 is connected to the aeration pump 4.

[0028] The condenser 1 is connected to the top of the composting reactor body 2, and its main function is to condense the gas discharged from the top of the composting reactor body 2. During the composting process, a large amount of ammonia volatile gas will be generated. The condenser 1 can lock the ammonia in the composting reactor to reduce its volatilization by lowering the temperature of the gas and liquefying and recovering the ammonia. The ammonia locked in the composting reactor is further converted into organic nitrogen by microorganisms and retained in the compost, and finally nitrogen-rich organic fertilizer is produced, which improves the overall resource utilization of the system. The composting reactor body 2 is used for composting and fermenting organic waste. In the reactor, organic waste is converted into stable, nutrient-rich organic fertilizer by the action of microorganisms. The composting reactor body 2 provides a closed and controllable composting environment, which helps to achieve a fast, efficient and stable composting process.

[0029] The gas flow meter 3 is connected to the composting reactor body 2 and is used to monitor and record the gas flow discharged from the reactor. Through the gas flow meter 3, the emission of gas in the reactor can be understood in real time, providing a basis for subsequent aeration treatment and ammonia recovery; secondly, it helps to accurately reflect the working status of the aeration pump 4 and realize accurate adjustment of the aeration amount. By monitoring the gas flow in real time, the gas flow meter 3 can promptly detect and handle abnormal conditions in the reactor to ensure the stable operation of the system.

[0030] The aeration pump 4 is connected to the gas flow meter 3 and is used to provide an appropriate amount of oxygen into the composting reactor body 2. Through the aeration effect of the aeration pump 4, the metabolic activity of the microorganisms in the reactor can be accelerated, and the decomposition and conversion of organic matter can be promoted. At the same time, aeration can also help reduce the ammonia nitrogen concentration in the reactor and reduce the emission of ammonia. By adjusting the aeration amount, accurate control of the oxygen content in the reactor can be achieved, thereby optimizing the growth environment of the microorganisms, improving the composting efficiency, and helping to achieve a fast, efficient and stable composting process, and improving the yield and quality of organic fertilizers; secondly, it also helps to reduce the ammonia nitrogen concentration in the reactor, reduce the emission of ammonia, and reduce pollution to the environment.

[0031] The composting reactor body 1 includes a base 203 and a barrel 202 disposed on the base 203; a barrel cover 201 is disposed on the top of the barrel 202; and the barrel cover 201 is connected to the condenser 1. The barrel 202 has a cavity structure inside, and the cavity structure is connected to the condenser 1. The bottom of the barrel 202 is connected to the gas flow meter 3 through a pipeline. The gas flow meter 3 is connected to the aeration pump 4 through an aeration pipe 5.

[0032] The base 203 provides stable support for the composting reactor body 1, ensuring the stability and safety of the entire system during operation. By providing stable support, the base 203 helps prevent the barrel 202 from deforming or collapsing due to gravity or internal pressure during the composting process, thereby ensuring the long-term stable operation of the system. The barrel 202 is used to accommodate organic waste and perform composting fermentation. Its interior is a cavity structure, which provides a suitable living environment for microorganisms and promotes the decomposition and transformation of organic matter. The cavity structure allows gas to flow freely in the reactor, which helps to achieve a fast, efficient and stable composting process. The barrel cover 201 is used to close the top of the barrel 202 to prevent external impurities from entering the reactor, and is connected to the condenser 1 to guide the gas generated in the reactor for condensation treatment; secondly, the compost material enters by opening the barrel cover 201, and the resulting organic fertilizer product is also taken out by opening the barrel cover 201.

[0033] The condenser tube 1 is a straight glass condenser tube with a length of 30 to 50 cm. The design of the straight glass condenser tube ensures that the flow path of ammonia in the condenser tube 1 is simple and direct, reducing the resistance and residence time of the gas during the condensation process, thereby improving the condensation efficiency. The condenser tube 1 of sufficient length provides sufficient condensation area, so that the gas derived from the composting reactor body 1 can fully contact the condenser tube wall to achieve efficient condensation. Secondly, the glass material makes the gas condensation process inside the condenser tube 1 clearly visible, which is convenient for the operator to observe and monitor the condensation effect. The visibility helps to promptly detect abnormal conditions in the condensation process, such as poor condensation effect or gas leakage, so as to take corresponding measures to make adjustments.

[0034] The present invention adds a condenser 1 on the basis of a traditional composting reactor, and the condenser 1 can lock ammonia in the composting reactor to reduce its volatilization. The ammonia locked in the reactor is further converted into organic nitrogen by microorganisms and retained in the compost, and finally nitrogen-rich organic fertilizer is produced. The condenser 1 used in the present invention does not pass circulating water and does not consume additional electric energy. The present invention has low operating costs, good ammonia emission reduction effects, and can significantly increase the nitrogen content in the compost product, and is suitable for large-scale applications.

[0035] A second object of the present invention is to provide a method for reducing ammonia emissions in compost and producing a nitrogen-rich organic fertilizer system, comprising the following steps: The compost material is added into the cavity structure of the compost reactor body 1 through the barrel cover 1 for composting, the aeration pump 4 is turned on, and the gas is transported to the compost reactor body 1 through the aeration pipe 5 for forced aeration, and the compost is turned when the compost temperature is greater than 50°C; when the compost temperature drops to the ambient temperature, the obtained compost is crushed, sieved and granulated to obtain nitrogen-rich organic fertilizer. The carbon-nitrogen ratio in the compost material is (20-30):1; the moisture content in the compost material is 55%-65%. The aeration rate is 0.05-0.3L min -1 kg -1 The frequency of turning the compost is 3 to 5 days per time.

[0036] Forced aeration not only provides sufficient oxygen for microorganisms, but also accelerates gas exchange during the composting process, which helps to reduce the ammonia nitrogen concentration inside the composting reactor, thereby reducing ammonia emissions. Turning the compost when the compost temperature is greater than 50°C can effectively prevent local overheating and agglomeration of the composting materials, ensuring the uniformity and stability of the composting process. Turning the compost can also promote oxygen exchange between composting materials, further improve the activity of microorganisms, and accelerate the decomposition of organic matter.

[0037] Example 1 Pig manure with a moisture content of about 70% and corn stalks are crushed to a particle size of 1-1.5 cm for later use; the above pig manure and corn stalks are mixed at a dry weight ratio of 1:1 to adjust the carbon-nitrogen ratio of the compost to about 25:1 and the moisture content to about 60%, and the compost mixture is mixed evenly; the above compost mixture is added to the cavity structure of the compost reactor body 1 through the barrel cover 1 for composting. The condenser tube 1 is made of glass with the specifications of: length 30 cm, inner diameter 2 cm, outer diameter 3.5 cm. Use the aeration pump 4 at an aeration rate of 0.2 L kg -1 min -1 Aeration is carried out under conditions to maintain an aerobic environment; during the high temperature period of composting (>50℃), the compost is turned every 3 days to mix it evenly; after 35 days, the mature compost is taken out, spread out for air drying, and then crushed, sieved and granulated to obtain a nitrogen-rich organic fertilizer product.

[0038] Example 2 The specific operation steps and composting conditions of Example 2 are consistent with those of Example 1, except that the specifications of the condenser tube 1 used in Example 2 are: length 50 cm, inner diameter 2 cm, outer diameter 3.5 cm.

[0039] Example 3 In a composting plant in Yangling, the composting raw materials are sewage sludge + crop straw. The carbon-nitrogen ratio of the composting mixture is about 20:1, and the water content is about 55%. The composting mixture is added into the cavity structure of the composting reactor body 1 through the barrel cover 1 for composting. The specifications of the condenser tube 1 are: length 30 cm, inner diameter 2 cm, outer diameter 3.5 cm. The aeration pump 4 is used at an aeration rate of 0.2 L kg -1 min -1 Aeration is carried out under conditions to maintain an aerobic composting environment; during the high temperature period of composting (>50℃), the compost is turned every 4 days to mix it evenly; after 35 days, the mature compost is taken out, spread out for air drying, and crushed, sieved and granulated to obtain a nitrogen-rich organic fertilizer product.

[0040] Example 4 In a composting plant in Yangling, the composting raw materials are a mixture of chicken manure + pig manure + cow manure + sludge + tail vegetables. The carbon-nitrogen ratio of the composting mixture is about 30:1, and the moisture content is about 65%. The above composting mixture is added into the cavity structure of the composting reactor body 1 through the bucket cover 1 for composting. The specifications of the condenser tube 1 are: length 30 cm, inner diameter 2 cm, outer diameter 3.5 cm. The aeration pump 4 is used at an aeration rate of 0.2 L kg -1 min -1Aeration is carried out under conditions to maintain an aerobic composting environment; during the high temperature period of composting (>50℃), the compost is turned every 5 days to mix it evenly; after 35 days, the mature compost is taken out, spread out for air drying, and crushed, sieved and granulated to obtain a nitrogen-rich organic fertilizer product.

[0041] Comparative Example 1 The specific operation steps and composting conditions of Control Example 1 are consistent with those of Example 1, except that Control Example 1 uses a conventional composting reactor (without adding a condenser 1).

[0042] Comparative Example 2 The specific operation steps and composting conditions of Control Example 2 are consistent with those of Example 3, except that Control Example 3 uses a conventional composting reactor (without adding a condenser 1).

[0043] Comparative Example 3 The specific operation steps and composting conditions of Control Example 3 are consistent with those of Example 4, except that Control Example 4 uses a conventional composting reactor (without adding a condenser 1).

[0044] The following test methods for the indicators involved in the embodiments and reference examples are as follows: Ammonia was absorbed with 2% boric acid solution and then determined by H2SO4 titration. The compost sample was mixed with 1 mol / L KCl solution at a ratio of 1:10 (W / V) and shaken for 2 hours. NO was determined using a flow analyzer. 3- -N and NH4 + -N content; total nitrogen (TN) was determined using a Kjeldahl nitrogen analyzer; organic nitrogen (ON) content was calculated according to the following formula: ON=TN−NO 3- -N−NH4 + -N Depend on Figure 2 (a) Figure 2 (b) It can be seen that compared with the control example 1, the total amount of ammonia emissions in Example 1 and Example 2 were significantly reduced by 59.3% and 61.1.3%, respectively. Figure 3 As shown, the TN content in the compost products of Example 1 and Example 2 is 19.4% and 20.3% higher than that of Control Example 1, respectively. The above results show that the present invention can effectively reduce the emission of ammonia during pig manure composting, while increasing the TN content of the compost product. At the same time, there is little difference between Example 1 and Example 2 in the improvement effect of ammonia emission reduction and TN content. Considering that the condenser tube 1 (length of 30 cm) used in Example 1 is shorter than that in Example 2, it is less expensive to use a 30 cm condenser tube 1.

[0045] Depend on Figure 4It can be seen that the TN and ON contents in the compost product of Example 3 are 18.6% and 19.9% ​​higher than those in Control Example 2, respectively. Figure 5 It can be seen that the TN and ON contents in the compost product of Example 4 are 25.3% and 23.4% higher than those in Control Example 3, respectively. The above results show that the present invention can effectively increase the TN and ON contents of sludge compost and the compost product of the mixture of chicken manure + pig manure + cow manure + sludge + tail vegetables.

[0046] In summary, the present invention can effectively reduce ammonia emissions during the composting process and increase the TN content of various organic waste compost products, has low operating costs, and is suitable for large-scale applications.

[0047] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A system for reducing ammonia emissions in compost and producing nitrogen-rich organic fertilizer, characterized in that: The composting reactor comprises a condenser (1), a composting reactor body (2), a gas flow meter (3) and an aeration pump (4); the condenser (1) is connected to the top of the composting reactor body (2); the composting reactor body (2) is connected to the gas flow meter (3); and the gas flow meter (3) is connected to the aeration pump (4).

2. A system for reducing ammonia emissions in compost and producing nitrogen-rich organic fertilizer according to claim 1, characterized in that: The composting reactor body (1) comprises a base (203) and a barrel body (202) arranged on the base (203); a barrel cover (201) is arranged on the top of the barrel body (202); and the barrel cover (201) is connected to the condensation pipe (1).

3. A system for reducing ammonia emissions in compost and producing nitrogen-rich organic fertilizer according to claim 2, characterized in that: The interior of the barrel body (202) is a cavity structure, and the cavity structure is connected to the condensation pipe (1).

4. A system for reducing ammonia emissions in compost and producing nitrogen-rich organic fertilizer according to claim 2, characterized in that: The bottom of the barrel body (202) is connected to a gas flow meter (3) via a pipeline.

5. A system for reducing ammonia emissions in compost and producing nitrogen-rich organic fertilizer according to claim 1, characterized in that: The gas flow meter (3) and the aeration pump (4) are connected via an aeration pipe (5).

6. A system for reducing ammonia emissions in compost and producing nitrogen-rich organic fertilizer according to claim 1, characterized in that: The condenser (1) is a straight glass condenser.

7. A method for using a system for reducing ammonia emissions in compost and producing nitrogen-rich organic fertilizer according to any one of claims 1 to 6, characterized in that: The following steps are involved: Compost material is added into the cavity structure of the compost reactor body (1) through the barrel cover (1) for composting, and the aeration pump (4) is turned on to transport gas into the compost reactor body (1) through the aeration pipe (5) for forced aeration. When the compost temperature is greater than 50° C., the compost is turned over; when the compost temperature drops to ambient temperature, the obtained compost is crushed, sieved and granulated to obtain nitrogen-rich organic fertilizer.

8. The method for using the system for reducing ammonia emission in compost and producing nitrogen-rich organic fertilizer according to claim 7, characterized in that: The carbon-nitrogen ratio of the compost material is (20-30):1; the moisture content of the compost material is 55%-65%.

9. The method for using the system for reducing ammonia emission in composting and producing nitrogen-rich organic fertilizer according to claim 7, characterized in that: The aeration rate is 0.05-0.3 L min -1 kg -1 Dry weight.

10. The method for using the system for reducing ammonia emission in composting and producing nitrogen-rich organic fertilizer according to claim 7, characterized in that: The frequency of turning the compost is 3 to 5 days / time.

Images