Accelerator for promoting anaerobic fermentation of excess sludge to produce short-chain fatty acid, method and application
By using a solution containing sodium chloride and betaine as a promoter, the problem of residual sludge organic matter releasing and reducing the activity of anaerobic microorganisms in the existing technology is solved, and efficient short-chain fatty acid production is achieved, which is suitable for application in coastal areas.
Patent Information
- Application Number
- CN202511083700.6
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-04
- Publication Date
- 2025-10-10
AI Technical Summary
The existing technology tends to reduce the acid production activity of anaerobic microorganisms when promoting the release of organic matter in the excess sludge, resulting in low acid production efficiency of anaerobic fermentation.
A solution containing sodium chloride and betaine is used as a promoter to promote the release of organic matter from residual sludge through a high osmotic pressure environment, and betaine is used to improve the tolerance of anaerobic microorganisms to salt and protect their activity.
It effectively promotes the release of organic matter in residual sludge, increases the yield and production efficiency of short-chain fatty acids, and has economic benefits, especially in coastal areas.
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Abstract
Description
Technical Field
[0001] The present application belongs to the technical field of sludge resource utilization, and in particular relates to a promoter, method and application of promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge. Background Art
[0002] With the process of urbanization, sewage treatment plants produce more and more residual sludge. Traditional methods of treating residual sludge are usually landfill, composting or incineration. These traditional sludge treatment methods are not only costly and wasteful, but may also pollute groundwater and the atmosphere again. Therefore, the resource development of residual sludge has important research significance.
[0003] Anaerobic fermentation acid production is an efficient and sustainable organic waste treatment technology. Anaerobic microorganisms can quickly convert complex organic matter in residual sludge into short-chain fatty acids such as acetic acid, significantly reducing environmental pollution and achieving resource recovery. Compared with traditional aerobic processes, it has the advantages of no need for aeration and low energy consumption; short reaction cycle, only a few hours to several days, and low sludge production. At the same time, the short-chain fatty acids such as acetic acid produced can be used as high-value-added products such as bioplastics, biofuels or carbon sources for sewage treatment, realizing the resource development of residual sludge and circular economy.
[0004] Anaerobic fermentation acid production technology primarily involves releasing organic matter from excess sludge, hydrolyzing this organic matter, and producing volatile fatty acids such as acetic acid. By enhancing the release of organic matter from excess sludge, the subsequent acid production process can be accelerated. Excess sludge is a collection of floccules formed by various microorganisms and the organic and inorganic matter they adsorb, containing a large number of microorganisms, proteins, and polysaccharides. Currently, some technologies use alkaline substances such as alkali residue, ammonium salts, cyclodextrins, and surfactants such as alkyl glycosides to break down the sludge's "outer wall," effectively releasing organic matter from the excess sludge and promoting the production of short-chain fatty acids. However, microorganisms are generally sensitive to pH, which can easily affect the activity of anaerobic microorganisms. Therefore, while the addition of accelerators such as alkali residue can promote the release of organic matter from excess sludge, it also has an adverse effect on the hydrolysis of organic matter by anaerobic microorganisms. Although it is also possible to utilize the genetic diversity and phenotypic differences of microorganisms to obtain target microbial strains with specific tolerances through microbial screening techniques, this also increases the technical complexity of anaerobic fermentation acid production technology and the cost of excess sludge treatment.
[0005] Therefore, developing an anaerobic fermentation acid production promoter that can not only promote the release of organic matter from excess sludge, but also enhance the tolerance of anaerobic microorganisms and increase the acid production activity of anaerobic microorganisms will be beneficial to further expand the widespread application of anaerobic fermentation acid production technology. Summary of the Invention
[0006] In view of this, the present application provides a promoter, method and application for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, which is used to solve the technical problem in the prior art that the acid production activity of anaerobic microorganisms is easily reduced when promoting the release of organic matter in excess sludge.
[0007] In a second aspect, the present application provides a promoter for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, comprising a sodium chloride solution and a betaine solution.
[0008] Preferably, the sodium chloride solute concentration in the sodium chloride-containing solution is 10-65 g / L, and the betaine solution concentration is 2-10 mmol / L.
[0009] Preferably, the sodium chloride solute concentration in the sodium chloride-containing solution is 36-54 g / L, and the betaine solution concentration is 6 mmol / L.
[0010] Preferably, the solution containing sodium chloride is seawater and / or a solution containing dissolved sodium chloride.
[0011] A second aspect of the present application provides a method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, comprising the following steps:
[0012] The step of preparing the fermentation material comprises uniformly mixing the sodium chloride solution, the excess sludge, the betaine solution and the anaerobic sludge to obtain the fermentation material;
[0013] The step of anaerobic fermentation is to subject the fermentation material to anaerobic fermentation to obtain short-chain fatty acids.
[0014] Preferably, the steps of preparing the fermentation material specifically include:
[0015] adding a solution containing sodium chloride to the excess sludge and stirring the mixture to obtain pretreated excess sludge;
[0016] adding the betaine solution to the anaerobic sludge and stirring evenly to obtain pretreated anaerobic sludge;
[0017] The pretreated excess sludge and the pretreated anaerobic sludge are mixed so that the sodium chloride-containing solution, the excess sludge, the betaine solution and the anaerobic sludge are evenly mixed to obtain a fermentation material.
[0018] Preferably, the sodium chloride solute concentration in the sodium chloride-containing solution added to the fermentation material is 10-65 g / L, and the concentration of the added betaine solution is 2-10 mmol / L.
[0019] Preferably, the sodium chloride solute concentration in the sodium chloride-containing solution added to the fermentation material is 36-54 g / L, and the concentration of the added betaine solution is 6 mmol / L.
[0020] Preferably, the anaerobic fermentation time is 10-20 days, and the culture temperature is 30-40°C.
[0021] Preferably, the stirring speed during the anaerobic fermentation process is 100-200 rpm.
[0022] Preferably, the sodium chloride-containing solution is obtained by dissolving sodium chloride in water to obtain the sodium chloride-containing solution or collecting seawater to obtain the sodium chloride-containing solution.
[0023] The third aspect of the present application provides the use of the promoter for promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge as described in the first aspect in the field of short-chain fatty acid production.
[0024] Compared with the prior art, the promoter for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids provided in this application has at least the following beneficial effects:
[0025] 1. The present application provides a promoter for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids. On the one hand, it can promote the full release of organic matter from the excess sludge, and on the other hand, it can protect the acid-producing anaerobic microorganisms and increase the production of short-chain fatty acids.
[0026] 2. The present application provides a promoter for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids. When the concentration of sodium chloride in the promoter is 36~54g / L, the addition of betaine can more effectively improve the production efficiency of short-chain fatty acids.
[0027] 3. The present application provides a promoter for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids. It can directly utilize seawater to promote the full release of organic matter from excess sludge. It is suitable for use in coastal areas with developed economies, scarce land, and large excess sludge production, and has significant economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS
[0028] In order to more clearly illustrate the specific implementation methods of the present application or the technical solutions in the prior art, the following is a brief introduction to the drawings required for use in the specific implementation methods or the description of the prior art. Obviously, the drawings described below are some implementation methods of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without any creative work.
[0029] Figure 1 A schematic diagram of the change in chemical oxygen demand (COD) concentration during days 1 to 16 of the anaerobic fermentation process of the method for promoting anaerobic fermentation of excess sludge to produce short-chain fatty acids provided in Examples 1-8 of the present application;
[0030] Figure 2A schematic diagram of the change in total short-chain fatty acid (VFA) concentration during days 1 to 16 of the anaerobic fermentation process of the method for promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge provided in Examples 1-8 of the present application;
[0031] Figure 3 Schematic diagram of the concentrations of different types of short-chain fatty acids produced during the anaerobic fermentation process 16 days after the method for promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge provided in Examples 1-8 of the present application. DETAILED DESCRIPTION
[0032] The present application provides a promoter, method and application for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, which is used to solve the technical problem in the prior art that the acid production activity of anaerobic microorganisms is easily reduced when promoting the release of organic matter in excess sludge.
[0033] The following will clearly and completely describe the technical solution of this application in conjunction with the accompanying drawings. Obviously, the embodiments described are only part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of this application.
[0034] In view of the fact that current promoters such as alkaline residue have an adverse effect on the activity of pH-sensitive anaerobic microorganisms, and easily reduce the acid production activity of anaerobic microorganisms when promoting the release of organic matter in residual sludge; the present application provides a promoter for promoting the anaerobic fermentation of residual sludge to produce short-chain fatty acids, and the promoter is composed of a sodium chloride solution and a betaine solution.
[0035] In a promoter provided by the present application for promoting the anaerobic fermentation of short-chain fatty acids in excess sludge, the solute sodium chloride in the sodium chloride-containing solution provides a high osmotic pressure environment, causing a large amount of water loss in the cells of the bacterial flocs in the excess sludge, resulting in a sharp shrinkage of the cell volume, triggering the collapse of the cell membrane lipid bilayer structure and the generation of microcracks. At the same time, the cell wall mechanically breaks due to the loss of hydration protection, the cells rupture and the cell contents flow out. The cell contents contain organic matter such as proteins and polysaccharides, which can be decomposed as substrates by anaerobic microorganisms to produce acid. Therefore, the sodium chloride in the promoter provided by the present application plays a role in promoting the release of organic matter from the excess sludge. In addition, since the betaine in the promoter acts as a compatible substance, it can improve the tolerance of anaerobic microorganisms to salt, thereby maintaining the water activity in the cells without interfering with the normal metabolism of the cells, alleviating the salt stress state of the anaerobic microorganisms, and avoiding the death of the microorganisms due to cell membrane rupture caused by excessive salt concentration, thereby improving the acid production efficiency of the anaerobic microorganisms.
[0036] Preferably, in the promoter for promoting the anaerobic fermentation of residual sludge to produce short-chain fatty acids provided in the present application, since different concentrations promote the release of organic matter in the residual sludge and generate different osmotic pressures, when the sodium chloride solute concentration is 36~54g / L, the amount of organic matter released is greater and the osmotic pressure is higher, the addition of betaine can more significantly promote the production of short-chain fatty acids, and has higher economic value.
[0037] Preferably, the source of the sodium chloride solution in the promoter can be prepared by dissolving sodium chloride in water, or seawater can be used directly. The salinity of seawater is about 3.6%, that is, each liter of seawater contains 36 grams of salt, and the concentration is about 36g / L, which just meets the sodium chloride concentration requirement in the promoter; and coastal areas have land shortages, developed economies, and high excess sludge production, while anaerobic fermentation acid production technology has the advantage of low sludge production. At the same time, it is convenient to collect seawater in coastal areas. Therefore, the promoter provided in this application is very suitable for use in coastal areas to promote the anaerobic fermentation of excess sludge to produce short-chain fatty acids.
[0038] At the same time, the present application also provides an application process of the promoter provided in the present application, which is to mix the sodium chloride-containing solution, residual sludge, betaine solution and anaerobic sludge evenly to obtain fermentation material, and then perform anaerobic fermentation to produce short-chain fatty acids.
[0039] Preferably, the present application also improves the process of adding the sodium chloride solution and the betaine solution to the promoter; the sodium chloride solution can be added to the residual sludge, stirred and tested with a salinity meter to obtain pretreated residual sludge, and the betaine solution is added to the anaerobic sludge and stirred evenly to obtain pretreated anaerobic sludge; the pretreated residual sludge and the pretreated anaerobic sludge are then mixed so that the sodium chloride solution, the residual sludge, the betaine solution and the anaerobic sludge are evenly mixed to obtain a fermentation material; pretreatment of the residual sludge with the sodium chloride solution is beneficial to the full release of organic matter in the residual sludge, while pretreatment of the anaerobic sludge with the betaine solution is beneficial to the protection of the anaerobic microorganisms by betaine, thereby improving the efficiency of acid production by anaerobic microorganisms.
[0040] From the above content, it can be seen that the promoter provided in this application can be used in the production of short-chain fatty acids such as acetic acid. That is, on the basis of the traditional production of short-chain fatty acids such as acetic acid using fossil energy as raw materials, a new process for the resource utilization of waste to produce short-chain fatty acids is provided.
[0041] The following is a detailed description of the promoter for promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge provided in the present application in combination with embodiments and experimental examples.
[0042] Example 1
[0043] This embodiment provides a method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, including the steps of preparing fermentation material and anaerobic fermentation.
[0044] The steps of preparing the fermentation material include:
[0045] First, the sludge from the secondary sedimentation tank of the sewage treatment plant is passed through a 100-mesh sieve, and then the sludge concentration (MLSS) is adjusted to about 20g / L, the total chemical oxygen demand (TCOD) is adjusted to about 20,000mg / L, and the soluble chemical oxygen demand (SCOD) is maintained at about 250mg / L as the residual sludge. Then, a solution containing sodium chloride is added and stirred for 3-5 minutes. The salinity can be measured with a salinometer. When the salinity meter reading reaches 1.8% (18g / L), the pretreated residual sludge is obtained;
[0046] Add 6 mmol / L betaine solution to the anaerobic tank sludge and stir for 3-5 minutes to mix it evenly to obtain pretreated anaerobic sludge;
[0047] The pretreated excess sludge and the pretreated anaerobic sludge are evenly mixed to obtain mixed sludge, which is used as fermentation material.
[0048] The steps of anaerobic fermentation include:
[0049] The fermentation material is subjected to anaerobic fermentation to obtain short-chain fatty acids; the fermentation time is about 16 days, the culture temperature is 35°C, and the stirrer speed during the fermentation process is 150 rpm.
[0050] Example 2
[0051] This embodiment provides a method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, including the steps of preparing fermentation material and anaerobic fermentation.
[0052] The steps of preparing the fermentation material include:
[0053] First, the sludge from the secondary sedimentation tank of the sewage treatment plant is passed through a 100-mesh sieve, and the sludge concentration (MLSS) is adjusted to about 20g / L, the total chemical oxygen demand (TCOD) is adjusted to about 20,000mg / L, and the soluble chemical oxygen demand (SCOD) is maintained at about 250mg / L as the residual sludge. Then, a solution containing sodium chloride is added and stirred for 3-5 minutes. The salinity can be measured with a salinometer. When the salinity meter reading reaches 3.6% (36g / L), the pretreated residual sludge is obtained;
[0054] Add 6 mmol / L betaine solution to the anaerobic tank sludge and stir for 3-5 minutes to mix it evenly to obtain pretreated anaerobic sludge;
[0055] The pretreated excess sludge and the pretreated anaerobic sludge are evenly mixed to obtain mixed sludge, which is used as fermentation material.
[0056] The steps of anaerobic fermentation include:
[0057] The fermentation material is subjected to anaerobic fermentation to obtain short-chain fatty acids; the fermentation time is about 16 days, the culture temperature is 35°C, and the stirrer speed during the fermentation process is 150 rpm.
[0058] Example 3
[0059] This embodiment provides a method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, including the steps of preparing fermentation material and anaerobic fermentation.
[0060] The steps of preparing the fermentation material include:
[0061] First, the sludge from the secondary sedimentation tank of the sewage treatment plant is passed through a 100-mesh sieve, and the sludge concentration (MLSS) is adjusted to about 20g / L, the total chemical oxygen demand (TCOD) is adjusted to about 20,000mg / L, and the soluble chemical oxygen demand (SCOD) is maintained at about 250mg / L as the residual sludge. Then, a solution containing sodium chloride is added and stirred for 3-5 minutes. The salinity can be measured with a salinometer. When the salinity meter reading reaches 5.4% (54g / L), the pretreated residual sludge is obtained;
[0062] Add 6 mmol / L betaine solution to the anaerobic tank sludge and stir for 3-5 minutes to mix it evenly to obtain pretreated anaerobic sludge;
[0063] The pretreated excess sludge and the pretreated anaerobic sludge are evenly mixed to obtain mixed sludge, which is used as fermentation material.
[0064] The steps of anaerobic fermentation include:
[0065] The fermentation material is subjected to anaerobic fermentation to obtain short-chain fatty acids; the fermentation time is about 16 days, the culture temperature is 35°C, and the stirrer speed during the fermentation process is 150 rpm.
[0066] Example 4
[0067] This embodiment provides a method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, including the steps of preparing fermentation material and anaerobic fermentation.
[0068] The steps of preparing the fermentation material include:
[0069] First, the sludge from the secondary sedimentation tank of the sewage treatment plant is passed through a 100-mesh sieve, and then the sludge concentration (MLSS) is adjusted to about 20g / L, the total chemical oxygen demand (TCOD) is adjusted to about 20000mg / L, and the soluble chemical oxygen demand (SCOD) is maintained at about 250mg / L as the residual sludge. No sodium chloride solution is added;
[0070] Add 6 mmol / L betaine solution to the anaerobic tank sludge and stir for 3-5 minutes to mix it evenly to obtain pretreated anaerobic sludge;
[0071] The residual sludge and the pretreated anaerobic sludge are evenly mixed to obtain mixed sludge, which is used as fermentation material.
[0072] The steps of anaerobic fermentation include:
[0073] The fermentation material is subjected to anaerobic fermentation to obtain short-chain fatty acids; the fermentation time is about 16 days, the culture temperature is 35°C, and the stirrer speed during the fermentation process is 150 rpm.
[0074] Example 5
[0075] This embodiment provides a method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, which serves as a comparative example of Example 1 and includes the steps of preparing fermentation material and anaerobic fermentation.
[0076] The steps of preparing the fermentation material include:
[0077] First, the sludge from the secondary sedimentation tank of the sewage treatment plant is passed through a 100-mesh sieve, and then the sludge concentration (MLSS) is adjusted to about 20g / L, the total chemical oxygen demand (TCOD) is adjusted to about 20,000mg / L, and the soluble chemical oxygen demand (SCOD) is maintained at about 250mg / L as the residual sludge. Then, a solution containing sodium chloride is added and stirred for 3-5 minutes. The salinity can be measured with a salinometer. When the salinity meter reading reaches 1.8% (18g / L), the pretreated residual sludge is obtained;
[0078] The pretreated residual sludge and the anaerobic sludge are mixed evenly to obtain mixed sludge, which is used as fermentation material.
[0079] The steps of anaerobic fermentation include:
[0080] The fermentation material is subjected to anaerobic fermentation to obtain short-chain fatty acids; the fermentation time is about 16 days, the culture temperature is 35°C, and the stirrer speed during the fermentation process is 150 rpm.
[0081] Example 6
[0082] This embodiment provides a method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, which serves as a comparative example of Example 2 and includes the steps of preparing fermentation material and anaerobic fermentation.
[0083] The steps of preparing the fermentation material include:
[0084] First, the sludge from the secondary sedimentation tank of the sewage treatment plant is passed through a 100-mesh sieve, and the sludge concentration (MLSS) is adjusted to about 20g / L, the total chemical oxygen demand (TCOD) is adjusted to about 20,000mg / L, and the soluble chemical oxygen demand (SCOD) is maintained at about 250mg / L as the residual sludge. Then, a solution containing sodium chloride is added and stirred for 3-5 minutes. The salinity can be measured with a salinometer. When the salinity meter reading reaches 3.6% (36g / L), the pretreated residual sludge is obtained;
[0085] The pretreated residual sludge and the anaerobic sludge are mixed evenly to obtain mixed sludge, which is used as fermentation material.
[0086] The steps of anaerobic fermentation include:
[0087] The fermentation material is subjected to anaerobic fermentation to obtain short-chain fatty acids; the fermentation time is about 16 days, the culture temperature is 35°C, and the stirrer speed during the fermentation process is 150 rpm.
[0088] Example 7
[0089] This embodiment provides a method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, which serves as a comparative example of Example 3 and includes the steps of preparing fermentation material and anaerobic fermentation.
[0090] The steps of preparing the fermentation material include:
[0091] First, the sludge from the secondary sedimentation tank of the sewage treatment plant is passed through a 100-mesh sieve, and the sludge concentration (MLSS) is adjusted to about 20g / L, the total chemical oxygen demand (TCOD) is adjusted to about 20,000mg / L, and the soluble chemical oxygen demand (SCOD) is maintained at about 250mg / L as the residual sludge. Then, a solution containing sodium chloride is added and stirred for 3-5 minutes. The salinity can be measured with a salinometer. When the salinity meter reading reaches 5.4% (54g / L), the pretreated residual sludge is obtained;
[0092] The pretreated residual sludge and the anaerobic sludge are mixed evenly to obtain mixed sludge, which is used as fermentation material.
[0093] The steps of anaerobic fermentation include:
[0094] The fermentation material is subjected to anaerobic fermentation to obtain short-chain fatty acids; the fermentation time is about 16 days, the culture temperature is 35°C, and the stirrer speed during the fermentation process is 150 rpm.
[0095] Example 8
[0096] This embodiment provides a method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids, as a comparative example of Example 4, including the steps of preparing fermentation material and anaerobic fermentation.
[0097] The steps of preparing the fermentation material include:
[0098] First, the sludge from the secondary sedimentation tank of the sewage treatment plant is passed through a 100-mesh sieve, and then the sludge concentration (MLSS) is adjusted to about 20g / L, the total chemical oxygen demand (TCOD) is adjusted to about 20000mg / L, and the soluble chemical oxygen demand (SCOD) is maintained at about 250mg / L as the residual sludge. No sodium chloride solution is added;
[0099] The residual sludge and anaerobic sludge are mixed evenly to obtain mixed sludge, which is used as fermentation material.
[0100] The steps of anaerobic fermentation include:
[0101] The fermentation material is subjected to anaerobic fermentation to obtain short-chain fatty acids; the fermentation time is about 16 days, the culture temperature is 35°C, and the stirrer speed during the fermentation process is 150 rpm.
[0102] Experimental Example 1
[0103] This experimental example takes samples during the anaerobic fermentation process of the method for promoting the anaerobic fermentation of excess sludge to produce short-chain fatty acids provided in Examples 1-8, and analyzes the chemical oxygen demand (COD), short-chain fatty acids and their accumulation within 1 to 16 days of anaerobic fermentation; the results are as follows: Figure 1-3 shown.
[0104] In the anaerobic digestion system, the chemical oxygen demand (COD) concentration can reflect the content and degradation degree of organic matter in the system; the chemical oxygen demand (COD) concentration during anaerobic fermentation is as follows: Figure 1 As shown, in combination with Examples 1-4 and Figure 1 It can be seen that as the concentration of sodium chloride increases from 0 to 54 (0 to 54 g / L), the concentration of chemical oxygen demand (COD) increases, indicating that sodium chloride can repeatedly promote the release of organic matter from excess sludge; and by comparing Examples 1 and 5, Examples 2 and 6, and Examples 3 and 7, it can be seen that when the same concentration of sodium chloride is added to the sludge, the chemical oxygen demand (COD) concentrations of Examples 1 to 3 with the addition of betaine are all lower than those of the experimental group without the addition of betaine, indicating that betaine improves the tolerance of anaerobic microorganisms to salt, thereby improving the efficiency of anaerobic microorganisms in digesting organic matter and producing acid.
[0105] Short-chain fatty acids are one of the important intermediate products in the anaerobic digestion of excess sludge by anaerobic microorganisms; short-chain fatty acids and their accumulation are as follows: Figure 2-3 As shown, from Figure 2-3It can be seen that when the concentration of sodium chloride ranges from 0 to 18 (0 to 54 g / L), the addition of betaine only slightly increases the production of short-chain fatty acids. However, when the concentration of sodium chloride ranges from 36 to 54 (0 to 54 g / L), it can be clearly seen that the addition of betaine significantly increases the production of short-chain fatty acids. This is because at lower salt concentrations, the osmotic pressure is not high, and anaerobic microorganisms will not suffer excessive cell membrane rupture and death. At high salt concentrations, the osmotic pressure is high, and anaerobic microorganisms are susceptible to salt stress and cell membrane rupture and death. The addition of betaine alleviates the salt stress of anaerobic microorganisms, thereby significantly improving the acid production efficiency of anaerobic microorganisms.
[0106] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.
Claims
1. A promoter for promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge, characterized in that: Includes sodium chloride solutions and betaine solutions.
2. The promoter for promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge according to claim 1, characterized in that The sodium chloride solute concentration in the sodium chloride-containing solution is 10-65 g / L, and the betaine solution concentration is 2-10 mmol / L.
3. The promoter for promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge according to claim 2, characterized in that The sodium chloride solute concentration in the sodium chloride-containing solution is 36-54 g / L.
4. The promoter for promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge according to claim 1, characterized in that The solution containing sodium chloride is seawater and / or a solution containing dissolved sodium chloride.
5. A method for promoting anaerobic fermentation of excess sludge to produce short-chain fatty acids, characterized in that: The following steps are involved: The step of preparing the fermentation material comprises uniformly mixing the sodium chloride solution, the excess sludge, the betaine solution and the anaerobic sludge to obtain the fermentation material; The step of anaerobic fermentation is to subject the fermentation material to anaerobic fermentation to obtain short-chain fatty acids.
6. The method for promoting anaerobic fermentation of excess sludge to produce short-chain fatty acids according to claim 5, characterized in that: The steps of preparing the fermentation material specifically include: adding a solution containing sodium chloride to the excess sludge and stirring the mixture to obtain pretreated excess sludge; adding the betaine solution to the anaerobic sludge and stirring evenly to obtain pretreated anaerobic sludge; The pretreated excess sludge and the pretreated anaerobic sludge are mixed so that the sodium chloride-containing solution, the excess sludge, the betaine solution and the anaerobic sludge are evenly mixed to obtain a fermentation material.
7. The method for promoting anaerobic fermentation of excess sludge to produce short-chain fatty acids according to claim 5, characterized in that: The anaerobic fermentation time is 10 to 20 days, and the culture temperature is 30 to 40°C.
8. The method for promoting anaerobic fermentation of excess sludge to produce short-chain fatty acids according to claim 5, characterized in that: The stirring speed during the anaerobic fermentation is 100-200 rpm.
9. The method for promoting anaerobic fermentation of excess sludge to produce short-chain fatty acids according to claim 5, characterized in that: The sodium chloride-containing solution is obtained by dissolving sodium chloride in water or collecting seawater to obtain the sodium chloride-containing solution.
10. Use of the promoter for promoting the production of short-chain fatty acids by anaerobic fermentation of excess sludge according to any one of claims 1 to 4 in the field of short-chain fatty acid production.