CN116768439A - A method and system for enhancing anaerobic digestion, hydrolysis and methane production of cow manure - Google Patents

Abstract

The invention belongs to the technical field of anaerobic digestion and hydrolysis. It discloses a method and system for strengthening the anaerobic digestion and hydrolysis of cow manure and methane production. The method first introduces Air, CO ₂ , N ₂ and He gases respectively through a nanobubble generator, Recirculate the distilled water in the container into the generator circulation system to prepare different types of nano-bubble water; mix the prepared different types of nano-bubble water with cow dung at a ratio of 1:1 for bottling, and seal it with a special lid for digestion reaction; choose to improve The NBW type that is more effective and economical and practical is then used for the AD process. The NBs of the present invention improve the AD system, promote the hydrolysis rate, enhance stability, and increase methane production.

Description

A method and system for enhancing anaerobic digestion, hydrolysis and methane production of cow manure

Technical field

The invention belongs to the technical field of anaerobic digestion and hydrolysis, and in particular relates to a method and system for enhancing the anaerobic digestion and hydrolysis of cow manure and methane production.

Background technique

Anaerobic digestion (AD) is a mature technology mediated by microorganisms. It can not only solve problems such as harmless treatment of waste, but also produce biogas rich in methane. However, AD is a multi-phase, multi-stage biochemical process with microorganisms as the main body. Each stage has its own unique microorganisms. These microorganisms have their own nutritional needs, environmental requirements and different sensitivities to environmental stress. However, they are They coexist in a mixed matrix and carry out series-ordered metabolic reactions. The metabolites of the previous metabolic group are often the substrates of the next group. Therefore, the AD process is very sensitive to disturbances. The instability of any link will lead to the collapse of the entire process. For example, ① Slow hydrolysis rate, especially for complex substrates (such as lignocellulose, etc.); ② Generation of volatile fatty acids (VFA) from rapidly biodegradable substrates (such as food waste); ③ Produce inhibitory products, such as ammonia and hydrogen sulfide; ④ Poor system stability and high sensitivity to changes in environmental factors. Some of these shortcomings can be addressed by employing various pretreatments or additives. However, factors such as complex processes, high energy and chemical requirements, and the generation of secondary pollutants result in few practical applications and high costs on an industrial scale.

Through the above analysis, the problems and defects existing in the existing technology are: complex process, high energy and chemical demand, production of secondary pollutants and high cost on an industrial scale.

Contents of the invention

In view of the problems existing in the prior art, the present invention provides a method and system for enhancing the anaerobic digestion, hydrolysis and methane production of cow manure.

The invention is implemented as follows: a method for strengthening the anaerobic digestion, hydrolysis and methane production of cow dung, including: preparing nanobubble water (NBW); mixing nanobubble water and cow dung for bottling; selecting appropriate NBW Type then perform the AD process.

Furthermore, the method of enhancing the anaerobic digestion, hydrolysis and methane production of cow manure includes the following steps:

Step 1. Preparation method of nanobubble water: introduce Air, CO ₂ , N ₂ and He gases respectively through the nanobubble generator, and recycle the distilled water in the container into the generator circulation system for 20 minutes;

Step 2: Mix the prepared different types of nano-bubble water and cow dung at a ratio of 1:1 for bottling, and seal it with a special lid for digestion reaction;

Step 3: Select the NBW type that has better improvement effect and is economical and practical before proceeding with the AD process.

Furthermore, the temperature passing through the nanobubble generator in step one is 20±2°C.

Furthermore, during the preparation of NBW in step 1, the pressure is controlled at 0.4MPa～0.5MPa.

Furthermore, the types of anaerobic fermentation bottles in step two are CO ₂ -NBW, He-NBW, N ₂ -NBW, Air-NBW and blank control group DW.

Furthermore, there are two small holes (inner diameter 6 mm) on the special cover for the digestion reaction in step 2. A silicone tube (inner diameter 6 mm) connects one hole to the air bag for biogas sampling, and a peristaltic pump is used in the other hole to collect the digested gas. sample.

Furthermore, in step two, the AD process was performed under high temperature (55±1°C) and medium temperature (37±1°C) conditions.

Further, select the Air-NBW type in step three.

Further, in step three, Air-NBW and cow dung are mixed and bottled at 1:1, 2:1 and 4:1 respectively, and three corresponding sets of blank controls are set: DW:CM=1:1, 2:1, 4:1, and the AD process was carried out under high temperature (55±1℃) and medium temperature (37±1℃) conditions respectively.

Another object of the present invention is to provide a method for strengthening the anaerobic digestion and hydrolysis of cow dung and the application of methane production in strengthening the anaerobic digestion and hydrolysis of cow dung and increasing methane production.

Combined with the above technical solutions and the technical problems to be solved, the advantages and positive effects of the technical solutions to be protected by the present invention are:

First, in view of the existing problems of complex processes, high energy, high demand for chemicals and the generation of secondary pollutants, the present invention provides a method for improving the AD performance of organic solid waste using NBs technology. The method first adopts The nanobubble generator introduces Air, CO ₂ , N ₂ and He gas respectively, and recirculates the distilled water in the container to the generator circulation system to prepare different types of nanobubble water; mix the prepared different types of nanobubble water with cow dung Carry out 1:1 mixing and bottling, and seal it with a special cap for digestion reaction; select the NBW type with better improvement effect and economical and practical before proceeding with the AD process.

Second, the present invention uses NBs to improve the AD system. The technical advantages are as follows:

① Promote hydrolysis rate: NBs can increase the activity of hydrolases (such as alkaline phosphatase, acid phosphatase, α-glucosidase) to promote the hydrolysis rate. In addition, there is a positive correlation between the hydrolysis rate and water mobility, and NBs can interfere with the hydrogen bonding network of water, thereby increasing water mobility.

② Enhance stability: NBs technology can alleviate acid suppression and ammonia suppression in the AD system, making the AD system more stable. For example, Air-Nanobubble water (Air-NBW) can create a microaerophilic environment for higher efficiency of the electron transfer system, thereby reducing volatile fatty acids by enhancing facultative bacterial activity, thereby alleviating acid inhibition; at the same time, it Has higher mobility and zeta potential (absolute value) to alleviate ammonia inhibition.

③ Increase methane production: Coenzyme F ₄₂₀ is an essential hydride carrier in the generation of hydrogenotrophic methane, and its activity affects methane production. The NBs technology can increase the activity of coenzyme F ₄₂₀ to increase methane production.

④NBs technology has a simple process, no added chemicals, low cost, green and environmentally friendly, and highly compatible with AD.

Third, the significant technical progress achieved in each main step of the present invention is as follows:

Step 1: Preparation method of nanobubble water

In this step, it is clarified that the method of introducing Air, CO ₂ , N ₂ and He gases respectively through the nanobubble generator and recycling the distilled water in the container to the generator circulation system for 20 minutes can make the preparation of nanobubble water More standardized and standardized.

Step 2: Mix the prepared different types of nanobubble water and cow dung at a ratio of 1:1 for bottling, and seal it with a special lid for digestion reaction.

In this step, it is clarified that the ratio of mixing and bottling is 1:1, and it is sealed with a special lid for digestion reaction, which can prevent other air components from entering the reaction system, thus ensuring the accuracy and stability of the reaction.

Step 3: Select the NBW type that has better improvement effect and is economical and practical before proceeding with the AD process.

In this step, a specific implementation plan of "selecting an NBW type with better improvement effect and being economical and practical before performing the AD process" is proposed. The appropriate NBW type can be selected according to the actual situation to perform the AD process, thereby improving the applicability and practicality of the method. sex.

In summary, each step further clarifies the implementation method and operating steps, thereby improving the stability, reliability and practicality of the method, and achieving higher technological progress.

Description of drawings

In order to explain the technical solutions of the embodiments of the present invention more clearly, the drawings required to be used in the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without exerting creative efforts.

Figure 1 is a flow chart of a method for enhancing the anaerobic digestion, hydrolysis and methane production of cow manure provided by an embodiment of the present invention;

Figure 2 is a diagram of the preparation mechanism of nanobubble water provided by the embodiment of the present invention;

Figure 3 is a diagram of an anaerobic fermentation bottle, a container for anaerobic digestion provided by an embodiment of the present invention;

Figure 4 is a graph showing the changes in pH, TA, and TVFA/TA during the anaerobic digestion process under high and medium temperature conditions provided by the embodiment of the present invention;

Figure 5 is a graph showing the changes in SCOD, TAN, and FAN during the anaerobic digestion process under high and medium temperature conditions provided by the embodiment of the present invention;

Figure 6 is a graph showing changes in cumulative methane production rate and daily methane production rate during the anaerobic digestion process under high and medium temperature conditions provided by the embodiment of the present invention.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with examples. It should be understood that the specific embodiments described here are only used to explain the present invention and are not intended to limit the present invention.

In view of the problems existing in the prior art, the present invention provides a method for enhancing the anaerobic digestion, hydrolysis and methane production of cow manure. The present invention will be described in detail below with reference to the accompanying drawings.

As shown in Figure 1, the method for enhancing the anaerobic digestion, hydrolysis and methanogenesis of cow manure provided by the embodiment of the present invention includes the following steps:

S101, prepare nano-bubble water;

S102, mix nano-bubble water and cow dung for bottling;

S103, select an appropriate NBW type and then perform the AD process.

As a preferred embodiment, the method for enhancing the anaerobic digestion, hydrolysis and methanogenesis of cow manure provided by the embodiment of the present invention specifically includes the following steps:

Step 1, preparation method of nano-bubble water: introduce Air, CO ₂ , N ₂ and He gases respectively through the nano-bubble generator, and recirculate the distilled water in the container into the generator circulation system for 20 minutes (Figure 2);

Step 2: Mix the prepared different types of nano-bubble water and cow dung at a ratio of 1:1 for bottling, and seal it with a special lid for digestion reaction;

Step 3: Select the NBW type that has better improvement effect and is economical and practical before proceeding with the AD process.

Further, the temperature passing through the nanobubble generator in step 1 is 20±2°C.

Furthermore, during the preparation of NBW in step 1, the pressure is controlled at 0.4MPa～0.5MPa.

Furthermore, the types of anaerobic fermentation bottles in step 2 are CO ₂ -NBW, He-NBW, N ₂ -NBW, Air-NBW and blank control group DW.

Furthermore, in step 2, there are two small holes (inner diameter 6 mm) on the special cover for the digestion reaction. A silicone tube (inner diameter 6 mm) connects one hole to the air bag for biogas sampling, and a peristaltic pump is used to collect the digested gas in the other hole. Sample (Figure 3).

Furthermore, in step 2, the AD process is performed under high temperature (55±1°C) and medium temperature (37±1°C) conditions.

Further, select the Air-NBW type in step 3.

Further, in step 3, Air-NBW and cow dung are mixed and bottled at 1:1, 2:1 and 4:1 respectively, and three corresponding sets of blank controls are set: DW:CM=1:1, 2:1, 4:1, and the AD process was carried out under high temperature (55±1℃) and medium temperature (37±1℃) conditions respectively.

The application embodiment of the present invention provides a method for enhancing the anaerobic digestion, hydrolysis and methane production of cow dung and its application in the anaerobic digestion, hydrolysis and methane production of cow dung.

The present invention combines total solids (TS), volatile solids (VS), gas volume, methane yield, trace elements (C, N, H, S), dissolved chemical oxygen demand (Soluble chemical oxygen demand (SCOD), pH, VFA, total ammonia nitrogen (TAN), free ammonia (Free ammonianitrogen (FAN)), total alkalinity (TA) and microbial community analysis as test indicators, in the 0th and 5th , 12, 22, 35, and 50 days were sampled respectively.

pH value is an important indicator of AD. Under high temperature conditions, the pH of each group of digestive juices during the AD process is stable between 8.06 and 8.45; under medium temperature conditions, the pH of each group of digestive juices is stable between 7.55 and 8. TA is closely related to buffering capacity. In the AD system, it is provided by ammonia nitrogen formed by deamination of nitrogen-containing organic matter. The TA of the high temperature group is approximately 8958.55~11883.87mg CaCO ₃ L ^-1 ; the TA of the medium temperature group is approximately 9672.06~12481.8mg. CaCO ₃ L ^-1 (Fig. 4).

TVFA/TA is a good indicator of AD stability. Under the high temperature conditions of the present invention, the TVFA/TA of each group on the 5th day is 0.78 for the DW group, 0.38 for the CO ₂ group, 0.75 for the N ₂ group, 0.62 for the He group, and 0.52 for the Air group; under medium temperature conditions, the TVFA/TA of each group on the 5th day /TA were 0.72 for the DW group, 0.63 for the CO ₂ group, 0.83 for the N ₂ group, 0.51 for the He group, and 0.34 for the Air group. It showed that the stability of anaerobic digestion in the Air group was the best (Figure 4).

SCOD is an important indicator representing dissolved reducing substances in digesta. The SCOD of each group on the 5th day under high temperature conditions were 18112.99 mg L ^-1 in the DW group, 16978.49 mg L ^-1 in the CO ₂ group, 18179.76 mg L ^-1 in the N ₂ group, 22178.28 mg L ^-1 in the He group, and 24163.66 mg in the Air group. L ^-1 ; SCOD of each group under medium temperature conditions were DW group 24640.86mg L ^-1 , CO ₂ group 24829.94mg L ^-1 , N ₂ group 23922.34mg L ^-1 , He group 25132.48mg L ^-1 , Air group 25208.11 mg L ^-1 (Figure 5). The Air group has the best effect on anaerobic digestion of organic matter.

Under high temperature conditions, the TAN of each group ranged from 1219 to 1633.33 mg L ^-1 , and the FAN of each group ranged from 353.04 to 419.47 mg L ^-1 ; under medium temperature conditions, the TAN of each group ranged from 1132.16 to 1606.66 mg L ^-1 , and the FAN of each group Between 50.62 and 167.62 mgL ^-1 (Figure 5), it shows that the methanogens in the mesophilic group are not affected by FAN.

The cumulative methane production rates of each group during the AD process under high temperature conditions were 192.90mL g ^-1 VS _added in the DW group, 226.12mL g ^-1 VS _added in the CO ₂ group (an increase of 17.22% compared with the DW group), and N ₂ group 198.98mL g ^-1 VS _added (an increase of 3.15% compared with the DW group), He group 184.74mL g ^-1 VS _added , and Air group 227.09mL g ^-1 VS _added (a 17.72% increase compared with the DW group) ; Under medium temperature conditions, the cumulative methane production rates of each group were 148.05mL g ^-1 VS _added in the DW group, 151.20mL g ^-1 VS _added in the CO ₂ group (an increase of 2.12% compared with the DW group), and 140.37 in the N ₂ group. mL g ^-1 VS _added , He group 154.85mLg ^-1 VS _added (an increase of 4.59% compared with the DW group), and Air group 162.39mL g ^-1 VS _added (a 9.68% increase compared with the DW group) (Figure 6 ). The Air group has the best effect on improving the AD process. The changing trends of the methane production rate in each group are basically the same, increasing first, then decreasing, and finally leveling off.

The following are specific solutions for each embodiment provided by the present invention:

1. Aquaculture waste treatment plan:

Step 1: Use a nanobubble generator to prepare nanobubble water. The specific steps are: introduce Air, CO ₂ , N ₂ and He gas respectively, and recirculate the distilled water in the container to the generator circulation system for 20 minutes.

Step 2: Mix the prepared nano-bubble water and aquaculture waste in a ratio of 1:1 and put them into a container sealed with a special lid for digestion reaction.

Step 3: Select the appropriate NBW type for the AD process. The appropriate NBW type can be selected based on the characteristics of the processing object and actual needs.

2. Urban sludge treatment plan:

Step 1: Use a nanobubble generator to prepare nanobubble water. The specific steps are: introduce Air, CO ₂ , N ₂ and He gas respectively, and recirculate the distilled water in the container to the generator circulation system for 20 minutes.

Step 2: Mix the prepared nano-bubble water and municipal sludge in a 1:1 ratio and put it into a container with a special cover for digestion reaction.

Step 3: Select the appropriate NBW type for the AD process. The appropriate NBW type can be selected based on the characteristics of the processing object and actual needs.

3. Agricultural waste treatment plan:

Step 1: Use a nanobubble generator to prepare nanobubble water. The specific steps are: introduce Air, CO ₂ , N ₂ and He gas respectively, and recirculate the distilled water in the container to the generator circulation system for 20 minutes.

Step 2: Mix the prepared nanobubble water and agricultural waste in a ratio of 1:1 and put it into a container with a special cover for digestion reaction.

Step 3: Select the appropriate NBW type for the AD process. The appropriate NBW type can be selected based on the characteristics of the processing object and actual needs.

4. Kitchen waste treatment plan:

Step 1: Use a nanobubble generator to prepare nanobubble water. The specific steps are: introduce Air, CO ₂ , N ₂ and He gas respectively, and recirculate the distilled water in the container to the generator circulation system for 20 minutes.

Step 2: Mix the prepared nano-bubble water and kitchen waste in a 1:1 ratio and put it into a container with a special cover for digestion reaction.

Step 3: Select the appropriate NBW type for the AD process. The appropriate NBW type can be selected based on the characteristics of the processing object and actual needs.

5. Biomass energy treatment plan:

Step 1: Use a nanobubble generator to prepare nanobubble water. The specific steps are: introduce Air, CO ₂ , N ₂ and He gas respectively, and recirculate the distilled water in the container to the generator circulation system for 20 minutes.

Step 2: Mix the prepared nano-bubble water and biomass energy in a ratio of 1:1 and put it into a container with a special cover for digestion reaction.

Step 3: Select the appropriate NBW type for the AD process. The appropriate NBW type can be selected based on the characteristics of the processing object and actual needs.

6. Sewage treatment plan:

Step 1: Use a nanobubble generator to prepare nanobubble water. The specific steps are: introduce Air, CO ₂ , N ₂ and He gas respectively, and recirculate the distilled water in the container to the generator circulation system for 20 minutes.

Step 2: Mix the prepared nano-bubble water and sewage in a ratio of 1:1 and put it into a container sealed with a special lid for digestion reaction.

Step 3: Select the appropriate NBW type for the AD process. The appropriate NBW type can be selected based on the characteristics of the processing object and actual needs.

The implementation of these specific plans requires attention to parameters such as temperature control, pH value control, and COD concentration control of the digestion reaction to ensure the effectiveness and efficiency of the AD reaction. At the same time, for different waste treatment objects, different NBW types need to be selected based on actual conditions to improve the efficiency and gas production of the AD process.

The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person familiar with the technical field shall, within the technical scope disclosed in the present invention, be within the spirit and principles of the present invention. Any modifications, equivalent substitutions and improvements made within the above shall be included in the protection scope of the present invention.

Claims (10)

1. A method for enhancing the anaerobic digestion, hydrolysis and methane production of cow manure, which is characterized by including: Preparation of nanobubble water; Nanobubble water is mixed with cow dung and bottled; Select the appropriate NBW type before proceeding with the AD process. 2. The method for strengthening the anaerobic digestion, hydrolysis and methane production of cow dung as claimed in claim 1, characterized in that the method for strengthening the anaerobic digestion, hydrolysis and methane production of cow dung includes the following steps: Step 1. Preparation method of nanobubble water: introduce Air, CO ₂ , N ₂ and He gases respectively through the nanobubble generator, and recycle the distilled water in the container into the generator circulation system for 20 minutes; Step 2: Mix the prepared different types of nano-bubble water and cow dung at a ratio of 1:1 for bottling, and seal it with a special lid for digestion reaction; Step 3: Select the NBW type that has better improvement effect and is economical and practical before proceeding with the AD process. 3. The method of enhancing anaerobic digestion, hydrolysis and methane production of cow manure as claimed in claim 2, characterized in that the temperature passing through the nanobubble generator in step one is 20±2°C; During the preparation of NBW in step 1, the pressure is controlled at 0.4MPa~0.5MPa. 4. The method for strengthening anaerobic digestion, hydrolysis and methane production of cow dung as claimed in claim 2, characterized in that the types of anaerobic fermentation bottles in step two are CO ₂ -NBW, He-NBW, N ₂ -NBW, and Air-NBW and blank control group DW. 5. The method of strengthening anaerobic digestion, hydrolysis and methane production of cow dung as claimed in claim 2, characterized in that in step two, there are two small holes on the special cover for the digestion reaction, and a silicone tube connects one hole to the air bag. For biogas sampling, a peristaltic pump was used in the other well to collect digestion samples. 6. The method for strengthening anaerobic digestion, hydrolysis and methane production of cow dung as claimed in claim 2, characterized in that step 2 is carried out under high temperature (55±1°C) and medium temperature (37±1°C) conditions. AD process. 7. The method for enhancing the anaerobic digestion, hydrolysis and methane production of cow dung according to claim 2, characterized in that the Air-NBW type is selected in step three. 8. The method for enhancing the anaerobic digestion, hydrolysis and methane production of cow dung as claimed in claim 2, characterized in that in step three, Air-NBW and cow dung are mixed at 1:1, 2:1 and 4:1 respectively. Bottle, and set corresponding three sets of blank controls DW:CM=1:1, 2:1, 4:1, and conduct AD under high temperature (55±1℃) and medium temperature (37±1℃) conditions respectively. process. 9. A system for enhancing the anaerobic digestion, hydrolysis and methane production of cow manure, which is characterized by including: Nanobubble water preparation module: prepare nanobubble water through a nanobubble generator; the generator introduces Air, CO ₂ , N ₂ and He gases, and circulates distilled water in the container into the generator circulation system and keeps circulating for 20 minutes. Thereby preparing nanobubble water; Cow dung and nano-bubble water mixing module: Mix the prepared nano-bubble water and cow dung in a ratio of 1:1, bottle it and seal it with a special lid for digestion reaction; NBW type selection module: According to needs, select the appropriate NBW type to further enhance the process of anaerobic digestion, hydrolysis and methane production of cow manure; in this module, the appropriate NBW type can be selected based on factors such as improvement effect and economic practicability. 10. Application of a method for enhancing the anaerobic digestion and hydrolysis of cow dung and methane production as described in any one of claims 1 to 8 in strengthening the anaerobic digestion and hydrolysis of cow dung and providing methane production.