Method for accelerating methane anaerobic biological oxidation rate

Abstract

The invention relates to the technical field of methane emission reduction, in particular to a method for accelerating methane anaerobic biological oxidation rate, which comprises the following steps: obtaining solid organic matters from a mixed biomass solid waste compost product, adding the solid organic matters into liquid containing methane anaerobic oxidation bacteria, and performing co-culture to obtain the methane anaerobic biological oxidation rate. And the anaerobic biological oxidation rate of methane is accelerated. By adding the solid organic matter, the energy metabolism of the methane anaerobic oxidation bacteria is enhanced, and the growth of the methane anaerobic oxidation bacteria is promoted, so that the anaerobic biological oxidation rate of methane is accelerated. According to the method, the solid organic matter which is obtained from the biomass solid waste compost product and is environmentally friendly, stable in property and not prone to loss is used for promoting anaerobic oxidation of methane, compared with an existing promoting method, the method is more efficient and environmentally friendly, cost is saved, and meanwhile a new mode is provided for recycling of the biomass solid waste compost product.

Description

Technical Field

[0001] The invention relates to a method for accelerating the anaerobic biological oxidation rate of methane, belonging to the technical field of methane emission reduction. Background Art

[0002] Methane is the world's second largest greenhouse gas, with a higher warming potential than carbon dioxide. Since the Industrial Revolution in the 18th century, the concentration of methane in the atmosphere has increased year by year, and has doubled by 2019. Methane emission reduction is one of the important topics in global climate change research and greenhouse gas control methods. However, traditional methane gas emission reduction technologies such as adsorption, catalytic oxidation, membrane separation, and cryogenic distillation are complex to operate, have high energy consumption, and are difficult to apply on a large scale.

[0003] Anaerobic methane oxidation can use methane as the only carbon source and energy source to convert it into other valuable chemicals. It is considered to be a clean, efficient, and scalable methane emission reduction technology. However, the growth of anaerobic methane oxidizing bacteria in the environment is slow and the anaerobic methane oxidation rate is low. Existing methods to accelerate anaerobic methane oxidation in the environment mainly include regulating and optimizing the habitat of anaerobic methane oxidizing bacteria, enhancing the electron transfer of anaerobic methane oxidizing bacteria through bioelectric stimulation, and adding biostimulants to promote enzyme activity. Although these methods can accelerate the anaerobic methane oxidation rate to varying degrees, they also increase the treatment cost and are prone to secondary pollution. Summary of the invention

[0004] The purpose of the present invention is to solve the deficiencies of the prior art and provide a method for accelerating the anaerobic biological oxidation rate of methane, which is low in cost, highly efficient and environmentally friendly.

[0005] Technical Solution

[0006] A method for accelerating the anaerobic biological oxidation rate of methane, characterized in that it comprises the following steps:

[0007] (1) Obtaining solid organic matter from mixed biomass solid waste composting products;

[0008] (2) Adding the solid organic matter obtained in step (1) to a liquid containing anaerobic methane oxidizing bacteria, after co-cultivation, the anaerobic biological oxidation rate of methane is accelerated.

[0009] Furthermore, in step (1), the method for obtaining solid organic matter from the mixed biomass solid waste compost product is as follows: 100 g of the mixed biomass solid waste compost product is air-dried and then passed through a 200 mesh sieve, 50 g of the sieved mixed biomass solid waste compost product is added to 0.1 mol / L HCl, ultrasonicated for 1 h and then centrifuged, the solid precipitate after centrifugation is added to deionized water for washing until the water phase is neutral, centrifuged, the solid precipitate after centrifugation is added to a mixed solution of 0.1 mol / L NaOH and 0.1 mol / L Na4P2O7 (volume ratio 1:1), oscillated at 35°C for 2 h, centrifuged, removed the supernatant, washed the solid precipitate after centrifugation with deionized water to remove residual NaOH and Na4P2O7, then washed with 6 mol / L HF and 10 mol / L HCl continuously to further remove minerals, centrifuged, and finally washed the solid precipitate after centrifugation with deionized water until the water phase is neutral, and freeze-dried to obtain solid organic matter.

[0010] The preparation method of the mixed biomass solid waste compost product comprises: mixing kitchen waste and corn stalks, adjusting the total C / N ratio of the mixture to 35, adjusting the initial moisture content to 60%, placing the mixture in a cylindrical polypropylene reactor for composting, setting the aeration rate to 0.4 L / min / (kg·total solids), and obtaining the mixed biomass solid waste compost product after the reactor is operated for 1 month.

[0011] Furthermore, in step (2), the co-cultivation of the liquid containing anaerobic methane oxidizing bacteria and the solid organic matter comprises the following steps:

[0012] 1) Add 40 mL of liquid containing anaerobic methane oxidizing bacteria and 0.2 g of solid organic matter into a vial, replace the headspace gas in the vial with nitrogen for 10 minutes, and then seal the vial cap;

[0013] 2) Add methane gas to the headspace of the vial to a volume fraction of 12% and shake to mix;

[0014] 3) Place the vial upside down in a 35°C incubator and regularly measure the methane content and microbial protein content.

[0015] The liquid containing anaerobic methane oxidizing bacteria is the effluent from the secondary sedimentation tank of a municipal sewage plant.

[0016] Beneficial effects of the present invention: The present invention utilizes solid organic matter obtained from the mixed biomass solid waste composting product to accelerate the anaerobic biological oxidation rate of methane. On the one hand, the solid organic matter can enhance the energy metabolism of methane anaerobic oxidizing bacteria, and on the other hand, it can also promote the growth of methane anaerobic oxidizing bacteria. The solid organic matter derived from the mixed biomass solid waste composting product is not only stable in nature and environmentally friendly, but also highly efficient and cost-saving compared to existing methods, without secondary pollution. At the same time, the present invention also provides a way to reuse the products after biomass solid waste composting treatment. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The test results of methane removal effect of the effluent from the secondary sedimentation tank of a municipal sewage treatment plant obtained by the method of Example 1 during the culture process;

[0018] Figure 2 The test results of the change of microbial protein content in the effluent of the secondary sedimentation tank of a municipal sewage treatment plant obtained by the method of Example 1 during the cultivation process are shown in FIG. DETAILED DESCRIPTION

[0019] The technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0020] Note: ① In the following embodiments, the liquid containing anaerobic methane oxidizing bacteria is the effluent from the secondary sedimentation tank of a municipal sewage plant.

[0021] ② In the following embodiments, the solid organic matter used is obtained from the mixed biomass solid waste compost product, and the obtaining method is as follows: 100 g of the mixed biomass solid waste compost product is air-dried and then passed through a 200-mesh sieve, 50 g of the sieved mixed biomass solid waste compost product is added to 250 mL of 0.1 mol / L HCl, ultrasonicated for 1 h, centrifuged at 6000 r / min for 15 min, the solid precipitate after centrifugation is added to 500 mL of deionized water for washing until the aqueous phase is neutral, centrifuged at 6000 r / min for 15 min, the solid precipitate after centrifugation is added to 500 mL of a mixed solution containing 0.1 mol / L NaOH and 0.1 mol / L Na4P2O7 (volume ratio 1:1), shaken at 35°C for 2 h, and centrifuged at 6000 r / min for 15 min, the solid precipitate after centrifugation was washed with deionized water to remove residual NaOH and Na4P2O7, and then washed with 6 mol / L HF and 10 mol / L HCl to further remove minerals. After centrifugation at 6000 r / min for 15 min, the solid precipitate was washed with deionized water until the water phase was neutral. After freeze-drying, solid organic matter was obtained.

[0022] The preparation method of the mixed biomass solid waste compost product comprises the following steps: mixing kitchen waste and corn stalks, adjusting the total C / N ratio of the mixture to 35, adjusting the initial moisture content to 60%, placing the mixture in a cylindrical polypropylene reactor with a diameter of 22.5 cm, a height of 26.5 cm, and an effective volume of 10 L for composting, setting the aeration rate to 0.4 L / min / (kg·total solids), and obtaining the mixed biomass solid waste compost product after the reactor has been running for 1 month.

[0023] Example 1

[0024] A method for accelerating the anaerobic biological oxidation rate of methane comprises the following steps:

[0025] 1) Add 40 mL of liquid containing methane anaerobic oxidizing bacteria (Note ①) and 0.2 g of solid organic matter (see Note ② for the method of obtaining) into a 60 mL vial, replace the headspace gas in the vial with nitrogen for 10 minutes, and then seal the vial cap;

[0026] 2) Use a sterile syringe to add methane gas into the headspace of the vial to a volume fraction of 12%, and shake to mix;

[0027] 3) Place the vial upside down in a 35°C incubator and regularly measure the methane content and microbial protein content.

[0028] In order to facilitate the comparison of the accelerating effect of solid organic matter on anaerobic oxidation of methane, three control culture groups were set up, namely: control group 1-no solid organic matter, control group 2-addition of biostimulant sulfate, control group 3-sterilization control, and cultured for 16 days. During the culture process, gas samples in the culture system were taken every 4 days, and the methane concentration was determined by gas chromatograph, and liquid samples were taken and the microbial protein content was determined by spectrophotometer. The test results are shown in Figure 1 and Figure 2 .

[0029] Figure 1 The test results of the methane removal effect of the effluent from the secondary sedimentation tank of a municipal sewage plant obtained by the method of Example 1 during the cultivation process are as follows: Figure 2 The test results of the change of microbial protein content in the effluent of the secondary sedimentation tank of the urban sewage treatment plant during the cultivation process obtained by the method of Example 1 show that after 16 days of cultivation, the methane in the culture system with added solid organic matter established according to the steps of Example 1 was completely removed, while only 11% of the methane was removed in the control group 1, and the methane removed in the control group 2 was only 1 / 3 of that in Example 1, and no obvious reaction occurred in the control group 3.

Claims

1. A method for accelerating the anaerobic biological oxidation rate of methane, characterized in that: The steps include: (1) Obtaining solid organic matter from mixed biomass solid waste composting products; (2) Adding the solid organic matter obtained in step (1) to a liquid containing anaerobic methane oxidizing bacteria, after co-cultivation, the anaerobic biological oxidation rate of methane is accelerated.

2. The method for accelerating the anaerobic biological oxidation rate of methane as claimed in claim 1, characterized in that: In step (1), the method for obtaining the mixed biomass solid waste compost product comprises the following steps: 1) Mixing kitchen waste and corn stalks, and adjusting the total C / N ratio of the mixture to 35 and the initial moisture content to 60%; 2) The mixture with adjusted C / N ratio and initial moisture content was placed in a cylindrical reactor for composting. The aeration rate was set to 0.4 L / min / (kg·total solids). After the reactor was operated for 1 month, the mixed biomass solid waste compost product was obtained.

3. The method for accelerating the anaerobic biological oxidation rate of methane as claimed in claim 1, characterized in that: In step (1), the method for obtaining solid organic matter from the mixed biomass solid waste compost product comprises the following steps: 1) 100 g of mixed biomass solid waste compost was air-dried and passed through a 200-mesh sieve. 50 g of the sieved mixed biomass solid waste compost was added to 0.1 mol / L HCl, ultrasonicated for 1 h, and centrifuged. 2) Wash the solid precipitate after centrifugation with deionized water until the water phase is neutral and centrifuge; 3) Add the solid precipitate after centrifugation to a mixed solution of 0.1 mol / L NaOH and 0.1 mol / L Na4P2O7 (volume ratio 1:1), shake at 35°C for 2 hours, and centrifuge; 4) Wash the solid precipitate after centrifugation with deionized water to remove residual NaOH and Na4P2O7, and centrifuge; 5) The solid precipitate after centrifugation is washed successively with 6 mol / L HF and 10 mol / L HCl to further remove minerals, and then centrifuged; 6) Wash the solid precipitate with deionized water until the water phase is neutral. After centrifugation, freeze-dry the solid precipitate to obtain solid organic matter.

4. The method for accelerating the anaerobic biological oxidation rate of methane as claimed in claim 1, characterized in that: In step (2), the co-cultivation of liquid containing anaerobic methane oxidizing bacteria and solid organic matter comprises the following steps: 1) Add 40 mL of liquid containing anaerobic methane oxidizing bacteria and 0.2 g of solid organic matter into a vial, replace the headspace gas in the vial with nitrogen for 10 minutes, and then seal the vial cap; 2) Add methane gas to the headspace of the vial to a volume fraction of 12% and shake to mix; 3) Place the vial upside down in a 35°C incubator and regularly measure the methane content and microbial protein content.

5. The method for accelerating the anaerobic biological oxidation rate of methane according to claim 1 or 4, characterized in that: The liquid containing anaerobic methane oxidizing bacteria is the effluent from the secondary sedimentation tank of the municipal sewage treatment plant.

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