Film covering composting method

Abstract

The invention relates to a film covering composting method. The method comprises the following steps: measuring the bound water content of a composting raw material; uniformly mixing the composting raw materials to form a compost body, and transferring the compost body into a composting device; covering and fixing a functional film above the composting barrel body, and inserting a thermocouple into the temperature measuring opening; setting aeration flow and time, and placing a certain amount of compost material on a digital balance in a drying oven at fixed time every day; the temperature of a compost body in the composting device and the reading of the digital balance are monitored in real time; calculating the combined water content and predicting the future aeration rate suitable for composting in the composting device according to the combined water content; the rotating speed of the air pump is adjusted in advance so as to realize accurate regulation and control of the fermentation process; composting for 15-30 days as required, and sampling through a sampling port as required to finally obtain a decomposed compost product. The problems of low aeration efficiency, high energy consumption, poor experiment repeatability and the like of composting of different materials in the composting process can be solved.

Description

Technical Field

[0001] The present application relates to the field of organic solid waste composting, and in particular to a film covering composting method. Background Art

[0002] Composting is a technology that can quickly stabilize and recycle organic solid waste. Aerobic composting technology is a microbial process that uses microorganisms that are ubiquitous in nature to transform a large amount of organic matter in the pile into more stable humus through aerobic fermentation under aerobic conditions. Among them, the moisture content of the material and the air volume are the key factors affecting the composting effect. The air volume (or ventilation volume) provides the oxygen required by microorganisms. Adequate oxygen helps the activity of aerobic microorganisms and promotes the decomposition of composting materials. If the ventilation is insufficient, it may lead to rotting under anaerobic conditions and produce undesirable gases such as hydrogen sulfide. Appropriate air volume helps to dissipate heat and prevent the temperature from being too high, so that the microorganisms can carry out decomposition activities within a suitable temperature range. The moisture content of the material will affect the diffusion of oxygen inside the pile. Generally speaking, materials with high moisture content have difficulty in oxygen diffusion and need to increase the aeration volume; materials with low moisture content have easy oxygen diffusion and only require a small amount of aeration or no aeration.

[0003] The moisture in organic solid waste can generally be divided into free water and bound water. Free water is water that is not affected by solid particles and is easy to remove, so it can be removed by conventional mechanical dehydration methods. Bound water is water that has physical or chemical effects with solid particles and is difficult to remove. Therefore, this part of water cannot be removed by conventional mechanical dehydration equipment. The vapor pressure, enthalpy heat and density of free water and bound water are not nearly the same. Since bound water is more difficult to evaporate than free water, the bound water content of the material can be calculated by the speed of water evaporation under constant temperature conditions. Due to differences in organic matter content, organic components, pore structure, etc., the bound water content of organic solid waste varies greatly. During the composting process, materials with different bound water contents have very different requirements for air volume. Therefore, it is necessary to develop a composting method based on the bound water content of the material. However, there are currently no relevant research reports. Summary of the invention

[0004] The purpose of the embodiments of the present application is to provide a membrane covering composting method to solve the problems of low aeration efficiency, high energy consumption, poor experimental repeatability, etc. of composting different materials during the composting process.

[0005] To achieve the above objectives, this application provides the following technical solutions:

[0006] The present application provides a film covering composting method, comprising the following specific steps:

[0007] Using a combined water content detection device to measure the combined water content of the compost raw materials;

[0008] The composting materials are mixed evenly to form a pile and transferred to the composting device;

[0009] Cover the functional film on the compost barrel and fix it, and insert the thermocouple into the temperature measuring port;

[0010] Set the aeration flow rate and time, and place a certain amount of compost material on the digital balance in the oven at a fixed time every day;

[0011] The temperature of the composting device and the reading of the digital balance are monitored in real time, and the temperature and quality data are transmitted to the computer of the main control module, and the computer records and saves the historical data;

[0012] The computer calculates the bound water content and predicts the amount of aeration suitable for composting in the future composting device based on the bound water content;

[0013] Adjust the air pump speed in advance to ensure that the aeration volume of the composting device reaches the predicted value stably, so as to achieve precise control of the fermentation process;

[0014] Compost for 15-30 days as needed, and take samples through the sampling port when necessary, and finally obtain a mature compost product.

[0015] The bound water content of the materials in the pile is less than 2kg per kilogram of absolutely dry material.

[0016] During the composting process, according to the daily measured bound water content between 0-2kg bound water / kg absolutely dry material, the aeration flow rate is 5-10L / min, 2-6 times a day, each time for 20-60min. If the bound water content is 0.5-1kg bound water / kg absolutely dry material, the aeration flow rate is 6-7.5L / min, 3-4 times a day, each time for 30-40min.

[0017] The film covering composting method adopts a film covering composting device, which includes a combined water content detection device, a composting device, and a data collection and automatic control device. The data collection and automatic control device is connected to the combined water content detection device and the composting device through a control line. The data collection and automatic control device is also connected to an air pump, which is connected to the combined water content detection device and the composting device respectively.

[0018] The combined water content detection device includes an oven and a balance. The balance is placed in the oven. A first gas flow meter is arranged outside the oven. One end of the first gas flow meter is connected to the inside of the oven, and the other end is connected to an air pump. The air pump and the first gas flow meter provide a constant airflow during the combined water determination process.

[0019] The composting device comprises a compost barrel body, a functional membrane is arranged above the compost barrel body, the functional membrane covers the compost barrel body and is fixed, a compost pile is arranged in the compost barrel body, a sampling port and a temperature measuring port are also provided on the compost barrel body, a filter plate is arranged below the compost pile body, a cavity is formed between the filter plate and the bottom of the compost barrel body, an aeration hole connected to the cavity is provided on the compost barrel body, the aeration hole is connected to an air pump through an aeration pipe, and a second gas flow meter is also provided between the air pump and the aeration hole.

[0020] The temperature measuring port is provided with a thermocouple inserted into the compost pile, and the temperature measuring port is connected to a temperature acquisition control unit, one end of the temperature acquisition control unit is connected to the temperature measuring port and the thermocouple, and the other end is connected to a data collection and automatic control device.

[0021] The functional film is a HDPE compost covering film.

[0022] The compost barrel is a PE barrel with a capacity of 80-150L.

[0023] The filter plate is provided with filter holes, and the height of the cavity is 3-5 cm.

[0024] The temperature measuring ports are provided at 3-5 locations, located at different directions of the compost barrel, and the height of the temperature measuring ports from the bottom is 15-60 cm.

[0025] The air pump is an AC / DC dual-purpose air pump with an aeration range of 0-15 L / min; the second gas flow meter is a rotor flow meter with a range of 0-10 L / min.

[0026] The upper limit of the oven temperature is 120-250° C., the volume is 60-120 L, and the gas flow rate of the first gas flow meter is 0-1000 mL / min.

[0027] Compared with the prior art, the beneficial effects of this application are:

[0028] Since materials with different combined water contents have different requirements for air volume during the composting process, it is necessary to control the aeration volume during the composting process based on the combined water content. The combined water content determination device in this application solves the problems of high unit price of special equipment, poor parallel performance due to small material testing volume, and difficulty in combining with composting equipment. This application uses combined water content to regulate the initial ratio and ventilation volume of composting materials; in addition, during the composting process, the ventilation volume is adjusted according to the changes in the combined water content of the materials. This solves the problems of low aeration efficiency, high energy consumption, and poor experimental repeatability of composting different materials during the composting process. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required for use in the embodiments of the present application will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present application 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 paying creative work.

[0030] Figure 1 is a flow chart of the method of the present invention;

[0031] Figure 2 is a sludge drying rate curve diagram of the present invention;

[0032] Figure 3 It is a diagram of a composting device of the present invention. DETAILED DESCRIPTION

[0033] The technical solutions in the embodiments of the present application will be described below in conjunction with the drawings in the embodiments of the present application. It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings.

[0034] The terms "comprises," "comprising," or any other variation thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes the element.

[0035] like Figure 1 As shown, the embodiment of the present application provides a film covering composting method, comprising the following specific steps:

[0036] Determine the bound water content of the compost raw materials using a bound water content detection device;

[0037] The composting materials are mixed evenly to form a pile and transferred to the composting device;

[0038] Cover the functional film on the compost barrel and fix it, and insert the thermocouple into the temperature measuring port;

[0039] Set the aeration flow rate and time, and place a certain amount of compost material on the digital balance in the oven at a fixed time every day;

[0040] The temperature of the composting device and the reading of the digital balance are monitored in real time, and the temperature and quality data are transmitted to the computer of the main control module, and the computer records and saves the historical data;

[0041] The computer calculates the bound water content and predicts the amount of aeration suitable for composting in the future composting device based on the bound water content;

[0042] Adjust the air pump speed in advance to ensure that the aeration volume of the composting device reaches the predicted value stably, so as to achieve precise control of the fermentation process;

[0043] Compost for 15-30 days as needed, and take samples through the sampling port when necessary, and finally obtain a mature compost product.

[0044] like Figure 3 A film covering composting method provided in an embodiment of the present application adopts a composting device based on combined water content control, the composting device comprises a combined water content detection device 2, a composting device 3, and a data collection and automatic control device 1, the data collection and automatic control device 1 is connected to the combined water content detection device 2 and the composting device 3 through a control line 7, the data collection and automatic control device 1 is also connected to an air pump 4, the air pump 4 is connected to the combined water content detection device 2 and the composting device 3 respectively. The data collection and automatic control device 1 is composed of a computer, a thermocouple, a control wire and a magnetic valve, and the computer is composed of a main control module, a data perception module and a logic controller.

[0045] The combined water content detection device 2 includes an oven and a balance 6, the balance 6 is placed in the oven, and a first gas flow meter 5 is arranged outside the oven. One end of the first gas flow meter 5 is connected to the inside of the oven, and the other end is connected to the air pump 4. The air pump 4 and the first gas flow meter 5 provide a constant airflow during the combined water determination process.

[0046] The composting device 3 includes a compost barrel body, a functional membrane 8 is arranged on the top of the compost barrel body, the functional membrane 8 covers the top of the compost barrel body and is fixed, a compost pile 10 is arranged in the compost barrel body, a sampling port 9 and a temperature measuring port 15 are also provided on the compost barrel body, a filter plate 11 is arranged below the compost pile body 10, a cavity 12 is formed between the bottom of the filter plate 11 and the bottom of the compost barrel body, an aeration hole 13 connected to the cavity 12 is provided on the compost barrel body, the aeration hole 13 is connected to the air pump 4 through an aeration pipe, and a second gas flow meter 14 is also provided between the air pump 4 and the aeration hole 13.

[0047] The temperature measuring port 15 is provided with a thermocouple 16 inserted into the compost pile 10 , and the temperature measuring port 15 is connected to a temperature acquisition control unit 17 , one end of the temperature acquisition control unit 17 is connected to the temperature measuring port 15 and the thermocouple 16 , and the other end is connected to the data collection and automatic control device 1 .

[0048] The functional film 8 is a HDPE compost covering film.

[0049] The compost barrel is a PE barrel with a capacity of 80-150L.

[0050] The filter plate 11 is provided with filter holes, and the height of the cavity 12 is 3-5 cm.

[0051] The temperature measuring ports 15 are provided at 3-5 locations, located at different directions of the compost barrel, and the height of the temperature measuring ports 15 from the bottom is 15-60 cm.

[0052] The air pump is an AC / DC dual-purpose air pump with an aeration range of 0-15 L / min; the second gas flow meter 14 is a rotor flow meter with a range of 0-10 L / min.

[0053] The upper limit of the oven temperature is 120-250° C., the volume is 60-120 L, and the gas flow rate of the first gas flow meter 5 is 0-1000 mL / min.

[0054] During the composting process, the aeration flow rate is 5-10 L / min, 2-6 times a day, and each time is 20-60 min, according to the daily measured bound water content of 0-2 kg bound water / kg absolute dry material. If the bound water content is 0.5-1 kg bound water / kg absolute dry material, the aeration flow rate is 6-7.5 L / min, 3-4 times a day, and each time is 30-40 min.

[0055] Specifically, materials with high bound water content include municipal sludge, feces, and stems and leaves of submerged plants; materials with low bound water content include straw, wood chips, and dredging sludge.

[0056] Embodiment 1 A film covering composting method comprises the following steps in sequence:

[0057] (1) 3 kg of plant stems, 5.75 kg of river and pond mud, 8 kg of pig manure and water were uniformly mixed, and the bound water content was measured to be 1.96 kg of bound water / kg of absolutely dry material. The mixture was then transferred into a barrel, covered with a functional film and fixed.

[0058] (2) Connect the air pump and flow meter, insert the thermocouple into the temperature measuring port, and observe the temperature through the computer.

[0059] (3) Samples were taken from the sampling port every day and placed in a glass container in the oven. The oven and air pump were turned on and the oven temperature was 40°C. On the first day, the bound water content was detected to be 1.62 kg bound water / kg absolutely dry material. Then, based on the bound water content, the aeration volume was controlled to 9 L / min, 50 min each time, 5 times a day.

[0060] (4) On the fourth day, the bound water content dropped to 0.98 kg bound water / kg absolute dry material, and the aeration volume was controlled at 7.5 L / min, 40 min each time, 4 times a day.

[0061] (5) On the 10th day, the bound water content dropped to 0.46 kg bound water / kg absolute dry material, and the aeration rate was controlled at 6.5 L / min, 30 min each time, 3 times a day. (6) Samples were taken and preserved on the 2nd, 4th, 7th, 10th, 15th and 20th days, and the composting continued for 20 days to obtain a mature compost product.

[0062] Embodiment 2 A film covering composting method comprises the following steps in sequence:

[0063] (1) 6 kg of plant leaves, 1 kg of rice straw, 3 kg of pig manure and water were uniformly mixed, and the bound water content was measured to be 1.49 kg bound water / kg of absolute dry material. The mixture was then transferred into a barrel, covered with a functional film and fixed with a rubber band.

[0064] (2) Connect the air pump and flow meter, insert the thermocouple into the temperature measuring port, and observe the temperature through the computer.

[0065] (3) Take samples through the sampling port every day and put them into the glass container of the oven. Turn on the oven and the air pump. The oven temperature is 40°C. On the first day, the bound water content is detected to be 1.01 kg bound water / kg absolutely dry material. Then, according to the bound water content, the aeration volume is controlled to 7.5 L / min, 40 min each time, 4 times a day. (4) On the sixth day, the bound water content drops to 0.64 kg bound water / kg absolutely dry material. The aeration volume is controlled to 7 L / min, 35 min each time, 3 times a day.

[0066] (5) On the 15th day, the bound water content dropped to 0.31 kg bound water / kg absolute dry material, and the aeration volume was controlled at 6 L / min, 25 min each time, 3 times a day.

[0067] (5) Samples were taken and preserved on the 3rd, 6th, 10th, 15th, 20th and 28th days, and the composting was continued for 28 days to obtain a mature compost product.

[0068] like Figure 2 The figure shows the weight loss curve of the sludge sample obtained from the experiment, where the temperature in the normal pressure box is 40°C, the nitrogen flow rate V=400mL / min, and the sludge thickness d=4mm. In the preheating zone, the sludge sample is heating up and has not yet reached equilibrium with the temperature inside the oven; in the constant rate evaporation zone, the evaporation rate is basically maintained at a certain value, and the main evaporation at this time is the free water of the sludge; in the first deceleration and second deceleration evaporation zones, the evaporation rate gradually decreases to 0, and the evaporation is the interstitial water and surface bound water of the sludge respectively; the remaining water that is difficult to evaporate at low temperature is the internal bound water, which can only be removed by drying at a temperature of 105°C.

[0069] The turning point between the constant evaporation period and the deceleration evaporation period represents the transition of the sludge drying process from being controlled by external conditions (temperature, relative humidity and gas flow rate, etc.) to being controlled by internal moisture migration properties. Therefore, the moisture content corresponding to this point is often used to measure the bound water content of sludge. Figure 2 It can be seen that the bound water content of the sludge measured by the thermal drying method under this working condition is 7.61 kg bound water / kg absolutely dry material.

[0070] The above description is only an embodiment of the present application and is not intended to limit the protection scope of the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A film covering composting method, characterized in that: The specific steps include: Using a combined water content detection device to measure the combined water content of the compost raw materials; The composting materials are mixed evenly to form a pile and transferred to the composting device; Cover the functional film on the compost barrel and fix it, and insert the thermocouple into the temperature measuring port; Set the aeration flow rate and time, and place a certain amount of compost material on the digital balance in the oven at a fixed time every day; The temperature of the composting device and the reading of the digital balance are monitored in real time, and the temperature and quality data are transmitted to the computer of the main control module, and the computer records and saves the historical data; Calculate the bound water content and predict the amount of aeration suitable for composting in the future composting device based on the bound water content; Adjust the air pump speed in advance to ensure that the aeration volume of the composting device reaches the predicted value stably, so as to achieve precise control of the fermentation process; Compost for 15-30 days as needed, and take samples through the sampling port when necessary, and finally obtain a mature compost product.

2. A film covering composting method according to claim 1, characterized in that: The bound water content of the materials in the pile is less than 2kg per kilogram of absolutely dry material.

3. A film covering composting method according to claim 1, characterized in that: During the composting process, according to the daily measured bound water content between 0-2kg bound water / kg absolutely dry material, the aeration flow rate is 5-10L / min, 2-6 times a day, each time for 20-60min. If the bound water content is 0.5-1kg bound water / kg absolutely dry material, the aeration flow rate is 6-7.5L / min, 3-4 times a day, each time for 30-40min.

4. A film covering composting method according to claim 1, characterized in that: The film covering composting method adopts a film covering composting device, which comprises a combined water content detection device (2), a composting device (3), and a data collection and automatic control device (1). The data collection and automatic control device (1) is connected to the combined water content detection device (2) and the composting device (3) via a control line (7). The data collection and automatic control device (1) is also connected to an air pump (4). The air pump (4) is connected to the combined water content detection device (2) and the composting device (3) respectively. The combined water content detection device (2) comprises an oven and a balance (6), wherein the balance (6) is placed in the oven, and a first gas flow meter (5) is arranged outside the oven, wherein one end of the first gas flow meter (5) is connected to the inside of the oven, and the other end is connected to an air pump (4), and the air pump (4) and the first gas flow meter (5) provide a constant airflow during the combined water determination process.

5. A film covering composting method according to claim 4, characterized in that: The composting device (3) comprises a compost barrel body, a functional membrane (8) is arranged above the compost barrel body, the functional membrane (8) covers the compost barrel body and is fixed, a compost pile (10) is arranged in the compost barrel body, a sampling port (9) and a temperature measuring port (15) are also provided on the compost barrel body, a filter plate (11) is arranged below the compost pile (10), a cavity (12) is formed between the bottom of the filter plate (11) and the bottom of the compost barrel body, an aeration hole (13) connected to the cavity (12) is provided on the compost barrel body, the aeration hole (13) is connected to an air pump (4) through an aeration pipe, and a second gas flow meter (14) is also provided between the air pump (4) and the aeration hole (13).

6. A film covering composting method according to claim 5, characterized in that: The temperature measuring port (15) is provided with a thermocouple (16) inserted into the compost pile (10); the temperature measuring port (15) is connected to a temperature acquisition control unit (17); one end of the temperature acquisition control unit (17) is connected to the temperature measuring port (15) and the thermocouple (16), and the other end is connected to a data collection and automatic control device (1).

7. A film covering composting method according to claim 5, characterized in that: The functional film (8) is a HDPE compost covering film.

8. A film covering composting method according to claim 5, characterized in that: The compost barrel is a PE barrel with a capacity of 80-150L.

9. A film covering composting method according to claim 5, characterized in that: The filter plate (11) is provided with filter holes, and the height of the cavity (12) is 3-5 cm.

10. The film covering composting method according to claim 5, characterized in that: The temperature measuring ports (15) are provided at 3-5 locations, located at different directions of the compost barrel, and the height of the temperature measuring ports (15) from the bottom is 15-60 cm; The air pump is an AC / DC dual-purpose air pump with an aeration range of 0-15 L / min; the second gas flow meter (14) is a rotor flow meter with a range of 0-10 L / min; The upper temperature limit of the oven is 120-250°C, the volume is 60-120L, and the gas flow rate of the first gas flow meter (5) is 0-1000mL / min.

Images