Method for producing marsh gas by treating and strengthening antibiotic mushroom dregs through co-anaerobic fermentation

Abstract

The invention discloses a method for producing biogas by strengthening antibiotic mushroom dregs through co-anaerobic fermentation treatment, and belongs to the technical field of biomass waste resource utilization. The method comprises the following steps: (1) acclimatization of an inoculum: taking cow dung as the inoculum, adding a mixture of straw and water every day for acclimatization, acclimatizing for 18-20 days, and collecting gas and collecting discharged materials every day according to set acclimatization time; and (2) anaerobic fermentation: taking antibiotic mushroom dregs, straws and water as raw materials, feeding the discharged material collected in the step (1) every day, carrying out anaerobic fermentation for 18-20 days, and carrying out gas collection and discharged material collection every day according to the set anaerobic fermentation time. According to the method, co-anaerobic fermentation is adopted to treat the antibiotic mushroom dregs, so that the yield of biogas and methane is effectively increased, meanwhile, the utilization rate of the antibiotic mushroom dregs is remarkably increased, and the problem of independent anaerobic fermentation inhibition of the antibiotic mushroom dregs is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass waste resource utilization, and more specifically relates to a method for producing biogas by treating antibiotic bacterial residues through anaerobic co-fermentation. Background Art

[0002] Antibiotics are now widely used in agriculture and healthcare around the world. However, the production of antibiotics produces a large amount of organic waste, namely antibiotic residues. For every ton of antibiotics produced, 8 to 10 tons of antibiotic residues are produced. The presence of high concentrations of residual antibiotics in antibiotic residues will seriously affect their treatment and resource utilization.

[0003] Anaerobic fermentation is an effective process for treating antibiotic residues. Studies have shown that low concentrations of antibiotics can promote the production of methane during anaerobic digestion. However, excessive concentrations of antibiotics will inhibit the performance of anaerobic digestion. Some studies have pointed out that the presence of excessive antibiotics will lead to excessive accumulation of volatile fatty acids, which may affect the activity of methanogenic microorganisms and lead to a decrease in biogas production. However, the anaerobic fermentation of a single substance is unbalanced and the C / N ratio is not appropriate, which affects the fermentation efficiency. Therefore, how to improve the fermentation efficiency of antibiotic residues, increase biogas production, and thereby improve its resource utilization capacity is an urgent problem to be solved in this field. Summary of the invention

[0004] The purpose of the present invention is to provide a method for enhancing biogas production by co-anaerobic fermentation of antibiotic bacterial residues, so as to solve the problem of low biogas production by anaerobic fermentation of antibiotic bacterial residues and achieve full utilization of the antibiotic bacterial residues.

[0005] To achieve the above object, the present invention provides the following solutions:

[0006] One of the technical solutions of the present invention is to provide a method for producing biogas by treating antibiotic residues through anaerobic co-fermentation, comprising the following steps:

[0007] (1) Inoculum domestication: Cow dung is used as the inoculum, and a mixture of straw and water is added daily for domestication. The domestication period is 18 to 20 days. Gas collection and discharge are performed daily according to the set domestication time;

[0008] (2) Anaerobic fermentation: using antibiotic bacterial residue, straw and water as raw materials, the discharged material collected in step (1) is fed daily, the anaerobic fermentation cycle is 18 to 20 days, and gas collection and discharged material are collected daily according to the set anaerobic fermentation time.

[0009] The present invention first uses cow dung as an inoculum to domesticate straw, and then uses antibiotic bacteria residue and straw as raw materials and adds the domesticated materials to coordinate continuous co-anaerobic fermentation, realizes the efficient conversion of antibiotic bacteria residue to methane, and solves the problem of low fermentation efficiency of single substance, overcomes the inhibition of biological treatment of antibiotic bacteria residue, and provides support, and further promotes the development of my country in the field of anaerobic fermentation of antibiotic bacteria residue to synthesize biogas, and contributes to the realization of antibiotic bacteria residue resource. Among them, cow dung contains a large amount of organic matter and nutrients, especially trace elements such as nitrogen, phosphorus, and potassium, which can provide necessary nutrients during anaerobic fermentation and promote the growth and reproduction of microorganisms. By adding cow dung as an inoculum, the fermentation effect can be improved, the quality and yield of the fermentation product can be improved, cow dung is used as an inoculum, straw is added for domestication, and the adaptability and activity of anaerobic fermentation microorganisms to the reaction environment are improved, thereby optimizing the fermentation process (the sign of the end of domestication and the start of formal experiments is that the daily gas production is stable). Straw has a high C content and is a potential raw material for anaerobic digestion. It can be used to produce biogas and can also be used as one of the substrates for anaerobic synergistic digestion. Antibiotic bacterial residue has a high N content, and its combination with straw can adjust the C / N of the system. Antibiotic bacterial residue and straw have certain complementarity in chemical composition. When they are fermented together, a synergistic effect will be produced, which promotes the metabolic activity of microorganisms. The resulting biogas output is higher than the effect of traditional anaerobic fermentation treatment using antibiotic bacterial residue alone, which effectively increases the methane output and significantly improves the utilization rate of antibiotic bacterial residue, solving the problem of anaerobic fermentation inhibition of antibiotic bacterial residue alone. In addition, antibiotic bacterial residue, as a by-product of the pharmaceutical industry, is usually regarded as waste, and improper treatment will cause pollution to the environment. Traditional methods of treating straw, such as landfill and incineration, have secondary pollution. The present invention realizes the recycling and reuse of straw and antibiotic bacterial residue.

[0010] Preferably, the straw includes crop straw such as corn straw and / or wheat straw; the antibiotic residue includes one or more of gentamicin residue, oxytetracycline residue and avermectin residue; the particle size of the straw and antibiotic residue is independently 20 to 60 mesh; this particle size can increase the specific surface area of ​​the straw and antibiotics, facilitating the attachment and degradation of microorganisms.

[0011] More preferably, the straw and antibiotic residue are crushed and sieved to a specific particle size and then placed in a cool and dry place for later use.

[0012] Preferably, in the step (1), the TS of the initial acclimation system when no mixture of straw and water is added is 2-6%; and the TS of the feed of the mixture of straw and water added daily is 2-6%.

[0013] Preferably, in step (1), the acclimation temperature is 36-38°C.

[0014] Preferably, in step (1), the cow dung is fermented before domestication, and the fermentation comprises: activating the cow dung under conditions of water bath treatment at 36-38° C.; wherein the cow dung is fermented in a container, and water is kept warm and flows in the interlayer formed by the water bath and the container to activate the cow dung.

[0015] Preferably, in step (2), the ratio of the VS of the antibiotic bacterial residue to the VS of the straw is 1:1; and the daily feed TS of the discharged material collected in step (1) is 2-6%.

[0016] Preferably, in step (2), the temperature of the anaerobic fermentation is 36-38° C., and the C / N ratio of the anaerobic fermentation is 10-35:1.

[0017] Preferably, in step (2), the anaerobic fermentation system is shaken 10 to 15 times per day during anaerobic fermentation; each shaking lasts for 10 to 20 minutes; the purpose of shaking is to prevent slagging on the surface of the anaerobic fermentation system.

[0018] More preferably, the reactor used for the anaerobic fermentation in step (2) is connected to a water bath to circulate hot water for heat preservation.

[0019] Preferably, the gas collected in step (2) is subjected to determination of biogas production and methane production; the biogas composition includes hydrogen, nitrogen, methane and carbon dioxide.

[0020] The present invention discloses the following technical effects:

[0021] 1. The present invention adopts co-anaerobic fermentation to treat antibiotic bacterial residue. The antibiotic bacterial residue and corn stalks have certain complementarity in chemical composition, and a synergistic effect will be produced during co-fermentation to promote the metabolic activity of microorganisms. The obtained biogas output is higher than the traditional technical solution of using antibiotic bacterial residue alone for anaerobic fermentation to produce biogas, which effectively increases the output of biogas and methane, and at the same time significantly improves the utilization rate of antibiotic bacterial residue, solving the problem of inhibition of anaerobic fermentation of antibiotic bacterial residue alone.

[0022] 2. The present invention uses antibiotic bacterial residue and corn stalks as raw materials. As a by-product of the pharmaceutical industry, antibiotic bacterial residue is usually regarded as waste, and improper treatment will cause environmental pollution. Corn stalks, as agricultural waste, are traditionally often burned or discarded, which also causes resource waste and environmental pollution problems. Combining the two for anaerobic fermentation realizes the resource utilization of waste and reduces the risk of environmental pollution.

[0023] 3. The entire process of the present invention does not introduce other chemical reagents and is environmentally friendly. DETAILED DESCRIPTION

[0024] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but should be understood as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0025] It should be understood that the terms described in the present invention are only for describing a particular embodiment and are not intended to limit the present invention. In addition, for the numerical range in the present invention, it should be understood that each intermediate value between the upper and lower limits of the scope is also specifically disclosed. The intermediate value in any stated value or stated range, and each smaller range between any other stated value or intermediate value in the described range is also included in the present invention. The upper and lower limits of these smaller ranges can be independently included or excluded in the scope.

[0026] Unless otherwise indicated, all technical and scientific terms used herein have the same meanings as those generally understood by those skilled in the art. Although the present invention describes only preferred methods and materials, any methods and materials similar or equivalent to those described herein may also be used in the implementation or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of a conflict with any incorporated document, the content of this specification shall prevail.

[0027] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments of the present invention description without departing from the scope or spirit of the present invention. Other embodiments derived from the present invention description will be apparent to those skilled in the art. The present invention description and examples are exemplary only.

[0028] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0029] The present invention first describes the raw materials and parameters involved in the following examples and comparative examples:

[0030] The cow dung used was obtained from a breeding farm in Tianjin, and the TS of cow dung was 30.66±0.03%;

[0031] The cow dung used was activated in a jar in a 37°C water bath before acclimation.

[0032] The gentamicin residue used was obtained from a pharmaceutical company in Tianjin; the corn stalks used were obtained from a corn planting base in Tianjin; other raw materials were all commercially available products unless otherwise specified.

[0033] The used gentamicin residue and corn stalks were processed as follows for later use: the gentamicin residue and corn stalks were mechanically crushed respectively, and sieved with a sieving device to obtain 35-mesh gentamicin residue and corn stalks, which were placed in a cool and dry place for later use.

[0034] The TS (Total Solid) involved refers to the total solid concentration, that is, the solid content in the fermentation raw materials after removing water; the VS involved refers to the material remaining after removing the ash from the total solids of the raw materials.

[0035] Example 1

[0036] This embodiment provides a method for synthesizing biogas by anaerobic fermentation of antibiotic bacterial residue and corn stalks:

[0037] 815g of cow dung and 4.2L of water were added to a CSTR reactor with an effective volume of 5L, so that the TS of the fermentation system was 5%. The gas bag was replaced regularly every day, and 250g of the discharge was collected. 10.9g of corn straw and 239.0mL of water were added for acclimatization. After the gas production was stable, the formal experiment began. 250g of the discharge was collected regularly every day, and 6.85g of gentamicin residue, 5.48g of corn straw and 238.0mL of water were added to make the VS of the fermentation system 2%. The fermentation cycle was set to 20d. The reaction system maintained the fermentation temperature at 37℃ through a circulating water bath. It was shaken 10 times a day; each shaking time was 10min to avoid surface hardening and slagging. The gas bag was replaced regularly every day, and the daily gas production and gas components were measured.

[0038] Biogas was measured by a gas chromatograph (GC2030, Shimadzu) equipped with a thermal conductivity detector (TCD). High-purity argon with a flow rate of 20 mL / min was used as the carrier gas, and the temperatures of the injector, chromatographic column and detector were set to 150°C, 120°C and 200°C, respectively. The standard gases used for calibration included CH4 with a volume fraction of 30%, CO2 with a volume fraction of 20%, N2 with a volume fraction of 40.01% and H2 with a volume fraction of 9.99%. The daily unloading centrifuge was used to separate the solid and liquid of the fermentation residue, and the filtered solid was placed in a 105°C oven to dry completely, then crushed and passed through a 35-mesh sieve, and the resulting biogas residue was sealed and stored in a ziplock bag.

[0039] It has been determined that the average daily biogas production is 1522.5 mL / g·VS, and the average daily methane production is 661.4 mL / g·VS.

[0040] Comparative Example 1

[0041] The difference from Example 1 is that the "5.48 g corn stalks" added in Example 1 is omitted, and the rest is the same as Example 1.

[0042] It has been determined that the average daily biogas production is 889.5 mL / g·VS, and the average daily methane production is 124.1 mL / g·VS.

[0043] By comparing Example 1 with Comparative Example 1, it can be seen that the process of preparing biogas by anaerobic fermentation of gentamicin residue and corn straw in Example 1 is significantly higher than that of preparing biogas by anaerobic fermentation of gentamicin residue in Comparative Example 1. This indicates that by adopting the method of anaerobic fermentation of gentamicin residue and corn straw, the antibiotic residue and corn straw have certain complementarity in chemical composition, and a synergistic effect will be produced during co-fermentation, which promotes the metabolic activity of microorganisms and effectively increases the production of biogas and methane.

[0044] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other.

[0045] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for producing biogas by treating antibiotic residues with anaerobic co-fermentation, characterized in that: The steps include: (1) Inoculum domestication: Cow dung is used as the inoculum, and a mixture of straw and water is added daily for domestication. The domestication period is 18 to 20 days. Gas collection and discharge are performed daily according to the set domestication time; (2) Anaerobic fermentation: using antibiotic bacterial residue, straw and water as raw materials, the discharged material collected in step (1) is fed daily, the anaerobic fermentation cycle is 18 to 20 days, and gas collection and discharged material are collected daily according to the set anaerobic fermentation time.

2. The method for producing biogas by anaerobic co-fermentation treatment of enhanced antibiotic bacterial residues according to claim 1, characterized in that: The straw includes crop straw such as corn straw and / or wheat straw; and / or the antibiotic residue includes one or more of gentamicin residue, oxytetracycline residue and avermectin residue; and / or the particle sizes of the straw and antibiotic residue are independently 20 to 60 meshes.

3. The method for producing biogas by anaerobic co-fermentation treatment of enhanced antibiotic bacterial residues according to claim 1, characterized in that: In the step (1), the TS of the initial acclimation system when no mixture of straw and water is added is 2-6%; the TS of the feed of the mixture of straw and water added daily is 2-6%.

4. The method for producing biogas by anaerobic co-fermentation treatment of enhanced antibiotic bacterial residues according to claim 1, characterized in that: In the step (1), the acclimation temperature is 36-38°C.

5. The method for producing biogas by anaerobic co-fermentation treatment of enhanced antibiotic bacterial residues according to claim 1, characterized in that: In the step (1), the cow dung is fermented before domestication, and the fermentation includes: activating the cow dung under the condition of treating it in a water bath at 36-38°C.

6. The method for producing biogas by anaerobic co-fermentation treatment of enhanced antibiotic bacterial residues according to claim 1, characterized in that: In step (2), the ratio of the VS of the antibiotic bacterial residue to the VS of the straw is 1:1; and the daily feed TS of the discharged material collected in step (1) is 2-6%.

7. The method for producing biogas by anaerobic co-fermentation treatment of enhanced antibiotic bacterial residues according to claim 1, characterized in that: In the step (2), the temperature of the anaerobic fermentation is 36-38° C., and the C / N of the anaerobic fermentation is 10-35:

1.

8. The method for producing biogas by anaerobic co-fermentation treatment of enhanced antibiotic bacterial residues according to claim 1, characterized in that: In the step (2), the anaerobic fermentation system is shaken 10 to 15 times per day during the anaerobic fermentation; each shaking lasts for 10 to 20 minutes.

9. The method for producing biogas by anaerobic co-fermentation treatment of enhanced antibiotic bacterial residues according to claim 1, characterized in that: The gas collected in step (2) is used to measure biogas production and methane production.