Method for resourceful treatment of blue-green algae and reed straws

Abstract

The invention provides a method for resourceful treatment of blue-green algae and reed straws, which comprises the following steps: (1) mixing dehydrated blue-green algae, crushed reed straws and water to obtain a mixture to be fermented; (2) introducing the to-be-fermented mixed material into an acidification hydrolysis fermentation tank, adding a first bacterial liquid, introducing protective gas, and carrying out acidification hydrolysis fermentation in a closed environment to obtain a fermented mixed material; (3) when the pH value and the acetic acid volume content of the fermented mixture reach target values, releasing the closed environment, and performing solid-liquid separation to obtain biogas slurry and biogas residues; (4) introducing the biogas slurry into an anaerobic methanogenesis fermentation tank, adding a second bacterial liquid, introducing protective gas for anaerobic methanogenesis fermentation, and collecting produced methane gas; and (5) introducing the biogas residue into an aerobic fermentation tank, adding an aerobic fermentation bacterial liquid, carrying out aerobic fermentation, and collecting the produced finished product organic fertilizer. According to the method provided by the invention, efficient reutilization of the blue-green algae and the reed straws is realized, the treatment efficiency and the gas production rate are improved, and large-scale popularization and application are facilitated.

Description

Technical Field

[0001] The invention belongs to the technical field of biomass conversion, and relates to a method for resource processing of biomass, and in particular to a method for resource processing of blue algae and reed straw. Background Art

[0002] In recent years, lakes in some parts of China have been facing eutrophication problems, and the situation is becoming increasingly serious. In order to improve the water quality of lakes, relevant governance projects are being actively promoted. In these governance projects, the salvage of cyanobacteria and the harvesting of aquatic plants have become important links. The excessive growth of cyanobacteria will not only lead to a decline in water quality and destroy the balance of the lake ecosystem, but some cyanobacteria can also release algal toxins that are harmful to human health, thus posing a threat to the safety of urban drinking water. In addition, aquatic plants (such as reed straw) that are regularly harvested during the lake governance process may also cause secondary pollution to the environment and lead to a waste of resources if not handled properly. Therefore, the rational treatment of these biomass is of great significance for environmental protection and resource recycling.

[0003] Accelerating the centralized treatment of cyanobacteria and the resource utilization of aquatic plants can not only effectively alleviate the problem of energy shortage, but also effectively prevent environmental pollution, showing great development potential and good application prospects. As a clean and renewable energy, biogas converts organic waste into energy, which not only realizes the recycling of resources but also avoids environmental pollution. Therefore, it has received great attention at home and abroad.

[0004] However, when applying traditional anaerobic fermentation methods to treat cyanobacteria and reed straw, some challenges are often encountered, such as fluctuations in gas production efficiency, decreased performance under low temperature conditions, high heating costs, and incomplete treatment of sludge.

[0005] It can be seen that how to provide a method for resource processing of cyanobacteria and reed straw, achieve efficient reuse of cyanobacteria and reed straw, and improve processing efficiency and gas production rate has become an urgent problem that technical personnel in this field need to solve. Summary of the invention

[0006] The object of the present invention is to provide a method for resource processing of cyanobacteria and reed straw, which realizes efficient recycling of cyanobacteria and reed straw, improves processing efficiency and gas production rate, and is conducive to large-scale promotion and application.

[0007] In order to achieve the purpose of the invention, the present invention adopts the following technical solutions:

[0008] The present invention provides a method for resource processing of blue algae and reed straw, the method comprising the following steps:

[0009] (1) mixing dehydrated blue algae, reed straw fragments and water to obtain a mixed material to be fermented;

[0010] (2) passing the mixture to be fermented obtained in step (1) into an acidification and hydrolysis fermentation tank, adding the first bacterial liquid and then passing a protective gas, and performing acidification and hydrolysis fermentation in a closed environment to obtain a fermented mixture;

[0011] (3) when the pH value and the volume content of acetic acid of the fermented mixture obtained in step (2) reach the target values, the sealed environment is released, and the biogas slurry and biogas residue are obtained after solid-liquid separation;

[0012] (4) passing the biogas slurry obtained in step (3) into an anaerobic methanogenic fermentation tank, adding the second bacterial liquid, passing a protective gas into the tank for anaerobic methanogenic fermentation, and collecting the produced methane gas;

[0013] (5) Passing the biogas residue obtained in step (3) into an aerobic fermentation tank, adding aerobic fermentation bacterial liquid to perform aerobic fermentation, and collecting the output finished organic fertilizer.

[0014] Among them, step (4) and step (5) are performed in no particular order.

[0015] The method provided by the present invention comprises three stages: acidification hydrolysis fermentation, anaerobic methanogenic fermentation and aerobic fermentation. The acidification hydrolysis fermentation converts cyanobacteria and reed straw into biogas slurry and biogas residue whose pH value and acetic acid volume content both reach target values. The anaerobic methanogenic fermentation further converts the biogas slurry into methane gas for reuse as clean energy, thereby reducing greenhouse gas emissions and having the dual advantages of environmental protection and economic benefits. The aerobic fermentation further converts the biogas residue into finished organic fertilizer, which can be used in agricultural production, soil improvement and other fields, thereby realizing the recycling of resources.

[0016] It can be seen that the three stages mentioned above cooperate with each other and complement each other. The cyanobacteria straw resource treatment is carried out by combining the physical and chemical properties of cyanobacteria and reed straw, the characteristics of anaerobic fermentation to produce methane, and the advantages of aerobic fermentation after dehydration of sludge. This realizes the efficient reuse of cyanobacteria and reed straw, improves the treatment efficiency and gas production rate, and is conducive to large-scale promotion and application.

[0017] Preferably, the water content of the dehydrated cyanobacteria in step (1) is 85wt%-90wt%, for example, 85wt%, 85.5wt%, 86wt%, 86.5wt%, 87wt%, 87.5wt%, 88wt%, 88.5wt%, 89wt%, 89.5wt% or 90wt%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0018] Preferably, the average particle size of the reed straw fragments in step (1) is 0.5-2 cm, for example, it can be 0.5 cm, 0.6 cm, 0.7 cm, 0.8 cm, 0.9 cm, 1 cm, 1.1 cm, 1.2 cm, 1.3 cm, 1.4 cm, 1.5 cm, 1.6 cm, 1.7 cm, 1.8 cm, 1.9 cm or 2 cm, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0019] Preferably, the moisture content of the mixture to be fermented in step (1) is 85wt%-95wt%, for example, it can be 85wt%, 86wt%, 87wt%, 88wt%, 89wt%, 90wt%, 91wt%, 92wt%, 93wt%, 94wt% or 95wt%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are equally applicable.

[0020] Preferably, the carbon-nitrogen mass ratio of the mixture to be fermented in step (1) is (23-27):1, for example, it can be 23:1, 23.5:1, 24:1, 24.5:1, 25:1, 25.5:1, 26:1, 26.5:1 or 27:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0021] Preferably, the height-to-diameter ratio of the acidification and hydrolysis fermentation tank in step (2) is (2-2.5):1, for example, it can be 2:1, 2.05:1, 2.1:1, 2.15:1, 2.2:1, 2.25:1, 2.3:1, 2.35:1, 2.4:1, 2.45:1 or 2.5:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0022] Preferably, the volume proportion of the mixture to be fermented in the acidification and hydrolysis fermentation tank in step (2) is 75%-85%, for example, it can be 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84% or 85%, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0023] Preferably, the hydraulic retention time of the fermented mixture in the acidification and hydrolysis fermentation tank in step (2) is 10-15 d, for example, it can be 10 d, 10.5 d, 11 d, 11.5 d, 12 d, 12.5 d, 13 d, 13.5 d, 14 d, 14.5 d or 15 d, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0024] Preferably, the organic load rate of the acidification and hydrolysis fermentation tank in step (2) is 1.9-2.1VS / L d, for example, it can be 1.9VS / L d, 1.91VS / L d, 1.93VS / L d, 1.95VS / L d, 1.97VS / L d, 1.99VS / Ld, 2VS / L d or 2.1VS / L d, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0025] Preferably, the first bacterial liquid in step (2) is a bacterial liquid obtained by enriching the anaerobic fermentation liquid through culturing with an aerobic acid-producing bacteria culture medium, an anaerobic acid-producing bacteria culture medium and an anaerobic cellulose-degrading bacteria culture medium.

[0026] Preferably, the protective gas in step (2) comprises nitrogen.

[0027] Preferably, the introduction time of the protective gas in step (2) is 0.5-1h, for example, it can be 0.5h, 0.6h, 0.7h, 0.8h, 0.9h or 1h, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0028] Preferably, the acidification and hydrolysis fermentation in step (2) is accompanied by stirring.

[0029] Preferably, the target pH value in step (3) is ≤6.5, for example, it can be 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4 or 6.5, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0030] Preferably, the target value of the acetic acid volume content in step (3) is ≥70%, for example, it can be 70%, 72%, 74%, 76%, 78%, 80%, 82%, 84%, 86%, 88% or 90%, but is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0031] Preferably, the height-to-diameter ratio of the anaerobic methanogenic fermentation tank in step (4) is (3.5-4):1, for example, it can be 3.5:1, 3.55:1, 3.6:1, 3.65:1, 3.7:1, 3.75:1, 3.8:1, 3.85:1, 3.9:1, 3.95:1 or 4:1, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0032] Preferably, the second bacterial liquid in step (4) is a bacterial liquid obtained by enriching anaerobic fermentation liquid with a methanogenic medium.

[0033] Preferably, the protective gas in step (4) comprises nitrogen.

[0034] Preferably, the introduction time of the protective gas in step (4) is 0.5-1h, for example, it can be 0.5h, 0.6h, 0.7h, 0.8h, 0.9h or 1h, but it is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0035] Preferably, the anaerobic methanogenic fermentation in step (4) is accompanied by stirring.

[0036] Preferably, the aerobic fermentation tank in step (5) is a horizontal aerobic fermentation tank.

[0037] Preferably, the aerobic fermentation in step (5) is carried out in a continuous feeding and discharging manner.

[0038] Preferably, the aerobic fermentation time in step (5) is 7-14 d, for example, it can be 7 d, 7.5 d, 8 d, 8.5 d, 9 d, 9.5 d, 10 d, 10.5 d, 11 d, 11.5 d, 12 d, 12.5 d, 13 d, 13.5 d or 14 d, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0039] Preferably, the aerobic fermentation in step (5) is accompanied by stirring, and the stirring frequency is 10-20 minutes per hour, for example, it can be 10 minutes, 11 minutes, 12 minutes, 13 minutes, 14 minutes, 15 minutes, 16 minutes, 17 minutes, 18 minutes, 19 minutes or 20 minutes, but it is not limited to the listed values, and other values ​​not listed within the numerical range are also applicable.

[0040] As a preferred technical solution of the present invention, the method comprises the following steps:

[0041] (1) mixing dehydrated blue algae with a moisture content of 85wt%-90wt%, reed straw fragments with an average particle size of 0.5-2cm, and water to obtain a mixture to be fermented with a moisture content of 85wt%-95wt%, and a carbon-nitrogen mass ratio of the mixture to be fermented of (23-27):1;

[0042] (2) introducing the mixture to be fermented obtained in step (1) into an acidification hydrolysis fermentation tank with a height-to-diameter ratio of (2-2.5):1, and controlling the volume proportion of the mixture to be fermented in the acidification hydrolysis fermentation tank to be 75%-85%, introducing nitrogen for 0.5-1h after adding the first bacterial liquid, and performing acidification hydrolysis fermentation in a closed environment while stirring, and controlling the hydraulic retention time of the mixture to be fermented in the acidification hydrolysis fermentation tank to be 10-15d, and the organic load rate of the acidification hydrolysis fermentation tank to be 1.9-2.1VS / L d, to obtain a fermented mixture;

[0043] (3) when the pH value of the fermented mixture obtained in step (2) is ≤6.5 and the volume content of acetic acid is ≥70%, the sealed environment is released, and the biogas slurry and biogas residue are obtained after solid-liquid separation;

[0044] (4) passing the biogas slurry obtained in step (3) into an anaerobic methanogenic fermentation tank with a height-to-diameter ratio of (3.5-4):1, adding the second bacterial liquid and then passing nitrogen for 0.5-1h, then performing anaerobic methanogenic fermentation while stirring, and collecting the produced methane gas;

[0045] (5) The biogas residue obtained in step (3) is passed into a horizontal aerobic fermentation tank, and after adding aerobic fermentation bacterial liquid, aerobic fermentation is carried out for 7-14 days in a continuous feeding and discharging manner, accompanied by stirring, and the stirring frequency is 10-20 minutes per hour, and the finished organic fertilizer is collected.

[0046] Wherein, the first bacterial liquid in step (2) is a bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with an aerobic acid-producing bacteria culture medium, an anaerobic acid-producing bacteria culture medium and an anaerobic cellulose-degrading bacteria culture medium; the second bacterial liquid in step (4) is a bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with a methanogenic culture medium; steps (4) and (5) are performed in no particular order.

[0047] The numerical range described in the present invention not only includes the point values ​​listed above, but also includes any point values ​​between the above numerical ranges that are not listed. Due to space limitations and for the sake of simplicity, the present invention no longer exhaustively lists the specific point values ​​included in the range.

[0048] Compared with the prior art, the present invention has the following beneficial effects:

[0049] (1) The method provided by the present invention comprises three stages: acid hydrolysis fermentation, anaerobic methanogenic fermentation and aerobic fermentation. The acid hydrolysis fermentation converts cyanobacteria and reed straw into biogas slurry and biogas residue whose pH value and acetic acid volume content reach target values. The anaerobic methanogenic fermentation further converts the biogas slurry into methane gas for reuse as clean energy, thereby reducing greenhouse gas emissions and having the dual advantages of environmental protection and economic benefits. The aerobic fermentation further converts the biogas residue into finished organic fertilizer, which can be used in agricultural production, soil improvement and other fields, thereby realizing the recycling of resources.

[0050] (2) The three stages above work together and complement each other. The cyanobacteria straw is processed for resource utilization by combining the physical and chemical properties of cyanobacteria and reed straw, the characteristics of anaerobic fermentation to produce methane, and the advantages of aerobic fermentation after dehydration of sludge. This achieves efficient reuse of cyanobacteria and reed straw, improves processing efficiency and gas production rate, and is conducive to large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 It is a schematic diagram of the structure of the device system adopted by the method for resource processing of blue algae and reed straw provided by the present invention.

[0052] Among them: 10-acidification and hydrolysis fermentation tank; 11-exhaust port; 12-feed port; 13-sampling port; 14-discharge port; 20-solid-liquid separation tank; 21-isolation net; 22-one-way exhaust hole; 23-slag outlet; 30-anaerobic methanogenic fermentation tank; 31-methane collection port; 32-liquid outlet; 40-horizontal aerobic fermentation tank; 41-feed hopper; 50-conveyor belt; 60-variable speed agitator; 70-heating layer; 80-insulation layer; 90-valve. DETAILED DESCRIPTION

[0053] The technical solution of the present invention is further described below by specific implementation methods. It should be understood by those skilled in the art that the embodiments are only to help understand the present invention and should not be regarded as specific limitations of the present invention.

[0054] The present invention provides a method for resource processing of blue algae and reed straw, wherein the method Figure 1 The device system shown in the figure comprises an acidification hydrolysis fermentation tank 10, a solid-liquid separation tank 20, an anaerobic methanogenic fermentation tank 30 and a horizontal aerobic fermentation tank 40. The acidification hydrolysis fermentation tank 10, the solid-liquid separation tank 20 and the anaerobic methanogenic fermentation tank 30 are sequentially connected by pipelines; the horizontal aerobic fermentation tank 40 is connected to the slag outlet 23 of the solid-liquid separation tank 20 by a conveyor belt 50.

[0055] Specifically, the height-to-diameter ratio of the acidification and hydrolysis fermentation tank 10 is 2.2:1, and the tank body and the tank cover are connected by threads; an exhaust port 11 is provided on the edge of the tank cover, a variable-speed agitator 60 is provided in the center of the tank cover, and the agitator rod and blades of the agitator are located in the center of the tank body; a feed port 12 is provided on the upper part of the tank body, a sampling port 13 is provided on the lower part of the tank body, the bottom is conical, and a discharge port 14 is provided at the bottom; a heating layer 70 and a heat-insulating layer 80 are provided on the outer wall of the tank from the inside to the outside.

[0056] Specifically, an isolation net 21 is provided inside the solid-liquid separation tank 20; the pipeline access port between the acidification hydrolysis fermentation tank 10 and the solid-liquid separation tank 20 is located at the lower part of the isolation net 21, and the pipeline access port between the solid-liquid separation tank 20 and the anaerobic methanogenic fermentation tank 30 is located at the upper part of the isolation net 21; the pipeline between the acidification hydrolysis fermentation tank 10 and the solid-liquid separation tank 20 and the pipeline between the solid-liquid separation tank 20 and the anaerobic methanogenic fermentation tank 30 are respectively and independently provided with valves 90; the top of the solid-liquid separation tank 20 is provided with a one-way exhaust hole 22, the bottom is conical, and a slag outlet 23 is provided at the bottom.

[0057] Specifically, the height-to-diameter ratio of the anaerobic methanogenic fermentation tank 30 is 3.6:1, and the tank body and the tank cover are connected by a flange; a methane collecting port 31 is provided on the edge of the tank cover, a variable-speed agitator 60 is provided in the center of the tank cover, and the agitator rod and blades of the agitator are located in the center of the tank body; the bottom is conical, and a liquid outlet 32 ​​is provided at the bottom; a heating layer 70 and a heat-insulating layer 80 are provided on the outer wall of the tank from the inside to the outside.

[0058] Specifically, a feed hopper 41 is provided on the top of the horizontal aerobic fermentation tank 40, and the feed hopper 41 is connected to the slag outlet 23 of the solid-liquid separation tank 20 through a conveyor belt 50; a variable speed agitator 60 is provided on the side end of the horizontal aerobic fermentation tank 40, and the agitator rod and blades of the agitator are located in the center of the tank body.

[0059] Specifically, the acidification and hydrolysis fermentation tank 10, the solid-liquid separation tank 20, the anaerobic methanogenic fermentation tank 30 and the horizontal aerobic fermentation tank 40 are all made of corrosion-resistant stainless steel materials.

[0060] Example 1

[0061] This embodiment provides a method for resource processing of blue algae and reed straw. The method is as follows: Figure 1 The device system shown in the figure specifically comprises the following steps:

[0062] (1) mixing dehydrated cyanobacteria with a moisture content of 88 wt%, reed straw fragments with an average particle size of 1.2 cm, and water to obtain a mixture to be fermented with a moisture content of 90 wt%, and a carbon-nitrogen mass ratio of the mixture to be fermented of 25:1;

[0063] (2) introducing the mixture to be fermented obtained in step (1) into an acidification and hydrolysis fermentation tank 10, and controlling the volume ratio of the mixture to be fermented in the acidification and hydrolysis fermentation tank 10 to be 80%, introducing nitrogen for 1 hour after adding the first bacterial liquid, closing all valves 90 to carry out acidification and hydrolysis fermentation, accompanied by stirring, and controlling the hydraulic retention time of the mixture to be fermented in the acidification and hydrolysis fermentation tank 10 to be 12 days, and the organic load rate of the acidification and hydrolysis fermentation tank 10 to be 2VS / L d, to obtain a fermented mixture;

[0064] (3) When the pH value of the fermented mixture obtained in step (2) is 6.1 and the volume content of acetic acid is 72%, the valve 90 and the exhaust port 11 are opened to obtain biogas slurry and biogas residue after separation by the isolation net 21 in the solid-liquid separation tank 20;

[0065] (4) passing the biogas slurry obtained in step (3) into the anaerobic methanogenic fermentation tank 30, adding the second bacterial liquid and then passing nitrogen for 1 hour, and then performing anaerobic methanogenic fermentation while stirring, and collecting the produced methane gas;

[0066] (5) passing the biogas residue obtained in step (3) into a horizontal aerobic fermentation tank 40, adding aerobic fermentation bacterial liquid, and performing aerobic fermentation for 10 days in a continuous feeding and discharging manner, accompanied by stirring, and the stirring frequency is 15 minutes per hour, and collecting the output finished organic fertilizer;

[0067] Among them, the first bacterial liquid in step (2) is the bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with an aerobic acid-producing bacteria culture medium, an anaerobic acid-producing bacteria culture medium and an anaerobic cellulose-degrading bacteria culture medium; and the second bacterial liquid in step (4) is the bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with a methanogenic culture medium.

[0068] Example 2

[0069] This embodiment provides a method for resource processing of blue algae and reed straw. The method is as follows: Figure 1 The device system shown in the figure specifically comprises the following steps:

[0070] (1) mixing dehydrated cyanobacteria with a moisture content of 85 wt%, reed straw fragments with an average particle size of 0.5 cm, and water to obtain a mixture to be fermented with a moisture content of 85 wt%, and a carbon-nitrogen mass ratio of the mixture to be fermented of 23:1;

[0071] (2) introducing the mixture to be fermented obtained in step (1) into an acidification and hydrolysis fermentation tank 10, and controlling the volume ratio of the mixture to be fermented in the acidification and hydrolysis fermentation tank 10 to be 75%, introducing nitrogen for 0.5 h after adding the first bacterial liquid, closing all valves 90 to carry out acidification and hydrolysis fermentation, accompanied by stirring, and controlling the hydraulic retention time of the mixture to be fermented in the acidification and hydrolysis fermentation tank 10 to be 10 d, and the organic load rate of the acidification and hydrolysis fermentation tank 10 to be 1.9 VS / L d, to obtain a fermented mixture;

[0072] (3) When the pH value of the fermented mixture obtained in step (2) is 6.5 and the volume content of acetic acid is 75%, the valve 90 and the exhaust port 11 are opened to obtain biogas slurry and biogas residue after separation by the isolation net 21 in the solid-liquid separation tank 20;

[0073] (4) passing the biogas slurry obtained in step (3) into the anaerobic methanogenic fermentation tank 30, adding the second bacterial liquid and then passing nitrogen for 0.5 h, and then performing anaerobic methanogenic fermentation while stirring, and collecting the produced methane gas;

[0074] (5) passing the biogas residue obtained in step (3) into a horizontal aerobic fermentation tank 40, adding aerobic fermentation bacterial liquid, and performing aerobic fermentation for 7 days in a continuous feeding and discharging manner, accompanied by stirring, and the stirring frequency is 10 minutes per hour, and collecting the output finished organic fertilizer;

[0075] Among them, the first bacterial liquid in step (2) is the bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with an aerobic acid-producing bacteria culture medium, an anaerobic acid-producing bacteria culture medium and an anaerobic cellulose-degrading bacteria culture medium; and the second bacterial liquid in step (4) is the bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with a methanogenic culture medium.

[0076] Example 3

[0077] This embodiment provides a method for resource processing of blue algae and reed straw. The method is as follows: Figure 1 The device system shown in the figure specifically comprises the following steps:

[0078] (1) mixing dehydrated cyanobacteria with a moisture content of 90 wt%, reed straw fragments with an average particle size of 2 cm, and water to obtain a mixture to be fermented with a moisture content of 95 wt%, and a carbon-nitrogen mass ratio of the mixture to be fermented of 27:1;

[0079] (2) introducing the mixture to be fermented obtained in step (1) into an acidification and hydrolysis fermentation tank 10, and controlling the volume ratio of the mixture to be fermented in the acidification and hydrolysis fermentation tank 10 to be 85%, introducing nitrogen for 0.8 h after adding the first bacterial liquid, closing all valves 90 to carry out acidification and hydrolysis fermentation, accompanied by stirring, and controlling the hydraulic retention time of the mixture to be fermented in the acidification and hydrolysis fermentation tank 10 to be 15 d, and the organic load rate of the acidification and hydrolysis fermentation tank 10 to be 2.1 VS / L d, to obtain a fermented mixture;

[0080] (3) When the pH value of the fermented mixture obtained in step (2) is 6 and the volume content of acetic acid is 70%, the valve 90 and the exhaust port 11 are opened to obtain biogas slurry and biogas residue after separation by the isolation net 21 in the solid-liquid separation tank 20;

[0081] (4) passing the biogas slurry obtained in step (3) into the anaerobic methanogenic fermentation tank 30, adding the second bacterial liquid and then passing nitrogen for 0.8 h, and then performing anaerobic methanogenic fermentation while stirring, and collecting the produced methane gas;

[0082] (5) passing the biogas residue obtained in step (3) into a horizontal aerobic fermentation tank 40, adding aerobic fermentation bacterial liquid, and then aerobic fermentation for 14 days in a continuous feeding and discharging manner, accompanied by stirring, and the stirring frequency is 20 minutes per hour, and the finished organic fertilizer is collected;

[0083] Among them, the first bacterial liquid in step (2) is the bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with an aerobic acid-producing bacteria culture medium, an anaerobic acid-producing bacteria culture medium and an anaerobic cellulose-degrading bacteria culture medium; and the second bacterial liquid in step (4) is the bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with a methanogenic culture medium.

[0084] Example 4

[0085] This embodiment provides a method for resource processing of blue algae and reed straw. Except for changing the moisture content of the fermented mixture in step (1) to 80wt% by adjusting the mixing amount of water, the remaining steps and conditions are the same as those in Example 1 and are not described in detail here.

[0086] Example 5

[0087] This embodiment provides a method for resource processing of blue algae and reed straw. Except that the hydraulic retention time of the fermented mixture in the acidification and hydrolysis fermentation tank 10 in step (2) is changed to 8 days, the remaining steps and conditions are the same as those in Example 1 and are not described in detail here.

[0088] Example 6

[0089] This embodiment provides a method for resource processing of blue algae and reed straw. Except that stirring is not performed during the acidification, hydrolysis and fermentation process in step (2), the remaining steps and conditions are the same as those in Example 1, so they are not described here in detail.

[0090] Example 7

[0091] This embodiment provides a method for resource processing of blue algae and reed straw. Except that stirring is not performed during the anaerobic methanogenic fermentation process in step (4), the remaining steps and conditions are the same as those in Example 1, and thus will not be described in detail here.

[0092] Example 8

[0093] This embodiment provides a method for resource processing of blue algae and reed straw. Except that stirring is not performed during the aerobic fermentation process in step (5), the remaining steps and conditions are the same as those in Example 1, so they are not described here in detail.

[0094] The results show that: Examples 1-8 were stable during operation, and finally achieved fermentation of blue algae and reed straw, converting low value-added biomass into high value-added methane gas and finished organic fertilizer. However, compared with Example 1, due to the lower moisture content of the fermented mixture in Example 4, the amount of biogas slurry obtained was less, and the fermentation sufficiency was insufficient; due to the short hydraulic retention time of the fermented mixture in Example 5, the fermentation sufficiency was also insufficient; since Examples 6-8 were not stirred at a certain fermentation stage, the fermentation uniformity was insufficient, and the fermentation sufficiency needed to be improved.

[0095] It can be seen that the method provided by the present invention includes three stages: acidification hydrolysis fermentation, anaerobic methanogenic fermentation and aerobic fermentation. The acidification hydrolysis fermentation converts cyanobacteria and reed straw into biogas slurry and biogas residue whose pH value and acetic acid volume content reach the target values. The anaerobic methanogenic fermentation further converts the biogas slurry into methane gas for reuse as clean energy, reducing greenhouse gas emissions and having the dual advantages of environmental protection and economic benefits. The aerobic fermentation further converts the biogas residue into finished organic fertilizer, which can be used in agricultural production, soil improvement and other fields, thereby realizing the recycling of resources.

[0096] Furthermore, the above three stages cooperate with each other and complement each other. The cyanobacteria straw is processed for resource utilization by combining the physical and chemical properties of cyanobacteria and reed straw, the characteristics of anaerobic fermentation to produce methane, and the advantages of aerobic fermentation after dehydration of sludge. This achieves efficient reuse of cyanobacteria and reed straw, improves processing efficiency and gas production rate, and is conducive to large-scale promotion and application.

[0097] The applicant declares that the above is only a specific implementation mode of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily thought of by those skilled in the art within the technical scope disclosed by the present invention shall fall within the protection scope and disclosure scope of the present invention.

Claims

1. A method for resource processing of blue algae and reed straw, characterized in that: The method comprises the following steps: (1) mixing dehydrated blue algae, reed straw fragments and water to obtain a mixed material to be fermented; (2) passing the mixture to be fermented obtained in step (1) into an acidification and hydrolysis fermentation tank, adding the first bacterial liquid and then passing a protective gas, and performing acidification and hydrolysis fermentation in a closed environment to obtain a fermented mixture; (3) when the pH value and the volume content of acetic acid of the fermented mixture obtained in step (2) reach the target values, the sealed environment is released, and the biogas slurry and biogas residue are obtained after solid-liquid separation; (4) passing the biogas slurry obtained in step (3) into an anaerobic methanogenic fermentation tank, adding the second bacterial liquid, passing a protective gas into the tank for anaerobic methanogenic fermentation, and collecting the produced methane gas; (5) passing the biogas residue obtained in step (3) into an aerobic fermentation tank, adding aerobic fermentation bacterial liquid to perform aerobic fermentation, and collecting the finished organic fertilizer; Among them, step (4) and step (5) are performed in no particular order.

2. The method according to claim 1, characterized in that The water content of the dehydrated cyanobacteria in step (1) is 85wt%-90wt%; Preferably, the average particle size of the reed straw fragments in step (1) is 0.5-2 cm.

3. The method according to claim 1 or 2, characterized in that: The moisture content of the mixture to be fermented in step (1) is 85wt%-95wt%; Preferably, the carbon-nitrogen mass ratio of the mixture to be fermented in step (1) is (23-27):

1.

4. The method according to any one of claims 1 to 3, characterized in that: The height-to-diameter ratio of the acidification and hydrolysis fermentation tank in step (2) is (2-2.5):1; Preferably, the volume proportion of the mixture to be fermented in step (2) in the acidification and hydrolysis fermentation tank is 75%-85%.

5. The method according to any one of claims 1 to 4, characterized in that: The hydraulic retention time of the fermented mixture in the acidification and hydrolysis fermentation tank in step (2) is 10-15 days; Preferably, the organic loading rate of the acidification and hydrolysis fermentation tank in step (2) is 1.9-2.1VS / L d.

6. The method according to any one of claims 1 to 5, characterized in that: Step (2) the first bacterial liquid is a bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with an aerobic acid-producing bacteria culture medium, an anaerobic acid-producing bacteria culture medium, and an anaerobic cellulose-degrading bacteria culture medium; Preferably, the protective gas in step (2) comprises nitrogen; Preferably, the introduction time of the protective gas in step (2) is 0.5-1h; Preferably, the acidification and hydrolysis fermentation in step (2) is accompanied by stirring.

7. The method according to any one of claims 1 to 6, characterized in that: The target pH value of step (3) is ≤6.5; Preferably, the target value of the acetic acid volume content in step (3) is ≥70%.

8. The method according to any one of claims 1 to 7, characterized in that: The height-to-diameter ratio of the anaerobic methanogenic fermentation tank in step (4) is (3.5-4):1; Preferably, the second bacterial liquid in step (4) is a bacterial liquid obtained by enriching the anaerobic fermentation liquid through culturing in a methanogenic medium; Preferably, the protective gas in step (4) comprises nitrogen; Preferably, the introduction time of the protective gas in step (4) is 0.5-1h; Preferably, the anaerobic methanogenic fermentation in step (4) is accompanied by stirring.

9. The method according to any one of claims 1 to 8, characterized in that: The aerobic fermentation tank in step (5) is a horizontal aerobic fermentation tank; Preferably, the aerobic fermentation in step (5) is carried out in a continuous feeding and discharging manner; Preferably, the aerobic fermentation time in step (5) is 7-14 days; Preferably, the aerobic fermentation in step (5) is accompanied by stirring, and the stirring frequency is 10-20 minutes per hour.

10. The method according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: (1) mixing dehydrated blue algae with a moisture content of 85wt%-90wt%, reed straw fragments with an average particle size of 0.5-2cm, and water to obtain a mixture to be fermented with a moisture content of 85wt%-95wt%, and a carbon-nitrogen mass ratio of the mixture to be fermented of (23-27):1; (2) introducing the mixture to be fermented obtained in step (1) into an acidification hydrolysis fermentation tank with a height-to-diameter ratio of (2-2.5):1, and controlling the volume proportion of the mixture to be fermented in the acidification hydrolysis fermentation tank to be 75%-85%, introducing nitrogen for 0.5-1h after adding the first bacterial liquid, and performing acidification hydrolysis fermentation in a closed environment while stirring, and controlling the hydraulic retention time of the mixture to be fermented in the acidification hydrolysis fermentation tank to be 10-15d, and the organic load rate of the acidification hydrolysis fermentation tank to be 1.9-2.1VS / L d, to obtain a fermented mixture; (3) when the pH value of the fermented mixture obtained in step (2) is ≤6.5 and the volume content of acetic acid is ≥70%, the sealed environment is released, and the biogas slurry and biogas residue are obtained after solid-liquid separation; (4) passing the biogas slurry obtained in step (3) into an anaerobic methanogenic fermentation tank with a height-to-diameter ratio of (3.5-4):1, adding the second bacterial liquid and then passing nitrogen for 0.5-1h, then performing anaerobic methanogenic fermentation while stirring, and collecting the produced methane gas; (5) passing the biogas residue obtained in step (3) into a horizontal aerobic fermentation tank, adding aerobic fermentation bacterial liquid, and performing aerobic fermentation for 7-14 days in a continuous feeding and discharging manner, accompanied by stirring, and the stirring frequency is 10-20 minutes per hour, and collecting the output finished organic fertilizer; Wherein, the first bacterial liquid in step (2) is a bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with an aerobic acid-producing bacteria culture medium, an anaerobic acid-producing bacteria culture medium and an anaerobic cellulose-degrading bacteria culture medium; the second bacterial liquid in step (4) is a bacterial liquid obtained by culturing and enriching the anaerobic fermentation liquid with a methanogenic culture medium; steps (4) and (5) are performed in no particular order.

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