Method for preparing regenerated carbon source for sewage treatment by using clostridium pasteurianum fermentation waste liquid and application of regenerated carbon source

Abstract

The invention belongs to the technical field of biological sewage treatment, and particularly relates to a method for preparing a regenerated carbon source for sewage treatment by using clostridium pasteurianum fermentation waste liquid and application. According to the method, traditional microbial fermentation industrial waste liquid such as clostridium pasteurianum fermentation waste liquid is adopted as raw materials, enzymolysis treatment is conducted through a specific enzyme preparation, membrane filtration operation is conducted, and finally the regenerated carbon source with the good nitrogen removal efficiency is prepared. The method has the beneficial effects that on one hand, high-concentration industrial organic wastewater is recycled, and the utilization rate of resources is increased; on the other hand, the regenerated carbon source with an excellent denitrification effect is prepared, the denitrification efficiency is up to 92.5%, and in addition, nitrogen-containing concentrated water and the like generated in the preparation process of the regenerated carbon source can be used as a nutrient solution of microorganisms so as to be recycled.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of sewage biological treatment, and particularly relates to a method for preparing a regenerated carbon source for sewage treatment from Clostridium pasteurii fermentation waste liquid and application thereof. BACKGROUND

[0002] At present, most sewage treatment plants are generally faced with the problem of insufficient carbon source in the denitrification process, and need to add additional carbon source. In order to ensure that the water quality of the effluent of the sewage treatment plant meets the standard, commercial carbon sources such as methanol and sodium acetate are added in the sewage treatment process, which greatly increases the cost of sewage treatment.

[0003] Industrial wastewater, especially industrial wastewater generated in the field of food industry, such as glucose crystallization mother liquor and microbial fermentation waste liquid, is rich in biodegradable organic carbon, including sugar, alcohol, organic acid and other nutrients, so it can be used as a high-quality composite carbon source for denitrification and denitrification of sewage treatment in theory.

[0004] However, in the actual application process, the following key technical problems need to be broken through due to the characteristics of the waste liquid itself, process adaptability and environmental risk factors: Firstly, the composition of the waste liquid is complex, and it generally has the characteristics of high COD concentration. If it is directly added as a carbon source to the sewage treatment system, it is easy to cause high load impact and toxicity inhibition of the denitrification system; Secondly, the waste liquid treatment process is complex and costly. If the treatment process is not proper, it is easy to cause loss of effective carbon source, introduction of nitrogen and phosphorus nutrients, and increase of the treatment load of total nitrogen and total phosphorus in the system. SUMMARY

[0005] In order to solve the above technical problems, the present application provides a method for preparing a regenerated carbon source for sewage treatment from Clostridium pasteurii fermentation waste liquid and application thereof.

[0006] The technical scheme of the present application is specifically: A new application approach of Clostridium pasteurii fermentation waste liquid is provided, that is, the Clostridium pasteurii fermentation waste liquid is used in sewage treatment.

[0007] As a preferred, the application is specifically that the Clostridium pasteurii fermentation waste liquid is used as a raw material to prepare a regenerated carbon source for sewage treatment. The Clostridium pasteurii fermentation waste liquid is a waste liquid containing protein, starch, glycerol, 1,3-propanediol, sodium acetate and sodium butyrate generated in the process of producing 1,3-propanediol by fermenting glycerol with Clostridium pasteurii.

[0008] As preferred, in the Clostridium butyricum fermentation waste liquid, per 100 parts of the Clostridium butyricum fermentation waste liquid, 0.5-1.5 parts of protein, 5-12 parts of starch, 5-10 parts of 1,3-propanediol, 3-8 parts of glycerol, 3-5 parts of sodium butyrate, 6-15 parts of sodium acetate, 0.03-0.05 parts of sulfate are contained.

[0009] Further, the application also provides a method for preparing a regenerated carbon source for sewage treatment by using Clostridium butyricum fermentation waste liquid, comprising the following steps: (1) Preparation of raw materials: collecting Clostridium butyricum fermentation waste liquid, and fully stirring the Clostridium butyricum fermentation waste liquid as a raw material for preparing a regenerated carbon source, for standby; (2) Enzymolysis: adding a compound enzyme preparation of amylase and glucoamylase into the raw material of (1) to perform enzymolysis, to obtain an enzymolysis liquid; (3) Ultrafiltration of the enzymolysis liquid in (2) by using an ultrafiltration membrane to obtain a cut-off liquid containing an effective carbon source; (4) Multi-effect evaporation and concentration of the cut-off liquid containing the effective carbon source separated in (3), and then adding small-molecule nutrient ingredients into the concentrated liquid and stirring uniformly, to obtain a regenerated carbon source.

[0010] In the preparation method of the regenerated carbon source, as preferred, in (2), the addition amount of the compound enzyme preparation in per liter of the raw material is 5-50 g, the enzymolysis temperature is 50-70℃, the pH is 4.0-7.0, and the enzymolysis time is 60-90 min.

[0011] As further preferred, in (2), the mass ratio of amylase to glucoamylase is 1-5:1.

[0012] As preferred, in (4), the small-molecule nutrient ingredients are selected from at least one of histidine, sodium glutamate, leucine, valine, vitamin B1, vitamin B 12 .

[0013] As further preferred, in (4), the small-molecule nutrient ingredients are histidine, sodium glutamate, and vitamin B 12 .

[0014] As preferred, in (4), per 100 parts of the concentrated liquid, 0.05-0.1 parts of histidine, 0.1-0.2 parts of sodium glutamate, and 0.1-0.15 parts of vitamin B 12 are added.

[0015] The regenerated carbon source prepared by using the above method is also the technical content which is protected by the application.

[0016] In addition, the application of the regenerated carbon source in sewage treatment is also the technical content which is protected by the application.

[0017] The present application has the advantages of: (1) The present application provides a new means for recycling Clostridium pasteurii fermentation waste liquid, i.e. using Clostridium pasteurii fermentation waste liquid as a direct raw material source for renewable carbon source for sewage treatment, realizing the recycling of high-concentration industrial organic wastewater and improving the utilization rate of resources; (2) The present application provides a renewable carbon source with excellent denitrification effect and a preparation method thereof, specifically using Clostridium pasteurii fermentation waste liquid as raw material, using a complex enzyme preparation of amylase and glucoamylase for enzymolysis, and preparing by membrane filtration treatment, the obtained carbon source shows excellent denitrification effect in sewage treatment, and the total nitrogen removal rate is as high as 92.5%; (3) In the preparation method of the renewable carbon source provided by the present application, on the one hand, the complex enzyme preparation of amylase and glucoamylase is used for enzymolysis of the waste liquid, which can fully enzymolyze most of the polysaccharide components such as starch in the waste liquid into small molecule carbon sources, and compared with the traditional step-by-step enzymolysis process, it has the advantages of time saving and simpler process; on the other hand, the protein and other impurity components contained in the waste liquid can also be separated from the system by membrane treatment, so as to avoid the increase of total nitrogen treatment load caused by the large amount of nitrogen nutrients contained in the renewable carbon source, and at the same time, the separated protein components can also be collected for preparing nutrient raw materials for microorganisms, which is a win-win situation. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 A schematic diagram of the method for preparing a renewable carbon source for sewage treatment from Clostridium pasteurii fermentation waste liquid provided by the present application; Figure 2 A comparison diagram of total nitrogen removal rate of the renewable carbon source prepared by each embodiment and the comparative example of the present application. DETAILED DESCRIPTION

[0019] In order to enable those skilled in the art to better understand the present application, the present application will be further described in conjunction with specific embodiments.

[0020] Example 1 The method for preparing a renewable carbon source for sewage treatment from Clostridium pasteurii fermentation waste liquid has a process flow as shown in Figure 1 The specific preparation steps are as follows: (1) Preparation of raw materials: take 1L of Clostridium pasteurii fermentation waste liquid, and reserve; The Clostridium butyricum fermentation waste liquid used in the present embodiment is the waste liquid produced in the whole process of preparing 1,3-propanediol by fermenting glycerol with Clostridium butyricum. The waste liquid contains 1.2 parts of protein, 8 parts of starch, 9 parts of 1,3-propanediol, 5.6 parts of glycerol, 5 parts of sodium butyrate, 8.2 parts of sodium acetate, 0.04 parts of magnesium sulfate, and the COD concentration of the waste liquid is about 150,000 mg / L, BOD5 / COD = 0.63, pH = 7.0, and the total phosphorus and total nitrogen are trace amounts, and the waste liquid basically does not contain chloride. Cr =0.63, pH = 7.0, and the total phosphorus and total nitrogen are trace amounts, and the waste liquid basically does not contain chloride; (2) Enzymolysis: 30 g of a composite enzyme preparation of α-amylase and glucoamylase was added to the raw material of (1), and the enzyme was allowed to react at 60°C and pH 5.0 for 90 min to obtain an enzyme hydrolysate, and the weight ratio of α-amylase to glucoamylase in the composite enzyme preparation was 2:1; (3) The enzyme hydrolysate in (2) was subjected to ultrafiltration with an ultrafiltration membrane having a molecular weight cut-off of 50 kDa to separate out macromolecular protein components and impurities, so as to obtain a cut-off liquid containing effective carbon sources and to prepare microbial nutrient components; (4) After evaporation and concentration by a multi-effect evaporator, small-molecule nutrient components were added to the cut-off liquid containing effective carbon sources separated out in (3), and the specific composition and addition amount were as follows: 0.05 g of histidine, 0.1 g of sodium glutamate, and 0.1 g of vitamin B0 were added to 100 g of the cut-off liquid, and the mixture was stirred uniformly to obtain a regenerated carbon source. 12 0.1g, stirring uniformly, to obtain a regenerated carbon source.

[0021] Example 2 The method for preparing a regenerated carbon source for wastewater treatment by using Clostridium butyricum fermentation waste liquid has a process flow as shown in Figure 1 , and the specific preparation steps are as follows: (1) Preparation of raw materials: same as in Example 1; (2) Enzymolysis: 40 g of a mixed enzyme preparation of α-amylase and glucoamylase was added to the raw material of (1), and the enzyme was allowed to react at 60°C and pH 5.0 for 90 min to obtain an enzyme hydrolysate, and the weight ratio of α-amylase to glucoamylase was 2:1; (3) and (4) are the same as in Example 1.

[0022] Example 3 The method for preparing a regenerated carbon source for wastewater treatment by using Clostridium butyricum fermentation waste liquid has a process flow as shown in Figure 1 , and the specific preparation steps are different from those of Example 1 in that: In the enzyme hydrolysis operation in (2), the weight ratio of α-amylase to glucoamylase was 1.5:1.

[0023] Example 4 The method for preparing a regenerated carbon source for wastewater treatment by using Clostridium butyricum fermentation waste liquid has a process flow as shown in Figure 1The difference between the shown specific preparation step and Example 1 is that: (2) In the enzymolysis operation, the weight ratio of α-amylase to glucoamylase is 3:1.

[0024] Comparative Example 1 The method for preparing the regenerated carbon source for wastewater treatment by using Clostridium pasteurianum fermentation waste liquid has the only difference from the specific operation of Example 1 that in (2), α-amylase is used for enzymolysis first, and then glucoamylase is added for enzymolysis after the enzymolysis is completed. The addition amount of the enzyme preparation and the enzymolysis conditions are the same as those in Example 1.

[0025] Comparative Example 2 The method for preparing the regenerated carbon source for wastewater treatment by using Clostridium pasteurianum fermentation waste liquid has the only difference from the specific operation of Example 1 that in (2), only α-amylase is used for enzymolysis. The addition amount of α-amylase is 30 g, and the enzymolysis conditions are the same as those in Example 1.

[0026] Comparative Example 3 The method for preparing the regenerated carbon source for wastewater treatment by using Clostridium pasteurianum fermentation waste liquid has the only difference from the specific operation of Example 1 that in (2), the mass ratio of α-amylase to glucoamylase is 1:2.

[0027] Comparative Example 4 The method for preparing the regenerated carbon source for wastewater treatment by using Clostridium pasteurianum fermentation waste liquid has the only difference from the specific operation of Example 1 that in (2), 30 g of papain is used to replace α-amylase for enzymolysis under the conditions of 50°C and pH 6.0 for 90 min to obtain an enzymolysis liquid.

[0028] Comparative Example 5 The Clostridium pasteurianum fermentation waste liquid is directly treated through (3)-(4) and used as a regenerated carbon source.

[0029] Application Example 1 The regenerated carbon sources prepared in each example and each comparative example of the application are used in the wastewater biological denitrification process to verify the denitrification effect, and the specific operation is as follows: At room temperature, the municipal wastewater sample to be treated is uniformly divided into multiple parts. The content of each index in the wastewater is as follows: the total nitrogen concentration is 58.64 mg / L, the COD is 220.00 mg / L, 100 mL of the regenerated carbon source is added per liter of wastewater, stirring is started, and the wastewater is treated at room temperature for 12 h. According to the total nitrogen concentration in the denitrification process, the effluent can reach the urban sewage level A standard, and the total nitrogen removal rate is calculated.

[0030] In the application example, the pH value is detected according to the electrode method specified in the HJ 1147-2020 standard; the chemical oxygen demand (COD) is determined by the dichromate method specified in the HJ / T 828-2017 standard; and the total nitrogen (TN) content is determined by the ultraviolet spectrophotometric method with alkaline potassium persulfate digestion specified in the HJ636-2012 standard. The detection results are shown in Table 1.

[0031] Table 1 Detection results of sewage treatment COD (mg / L) COD removal rate (%) TN (mg / L) Total nitrogen removal rate (%) Initial water quality 220 / 58.64 / Example 1 12.33 94.4 4.52 92.3 Example 2 12.15 94.5 4.37 92.5 Example 3 12.77 94.2 5.30 91.0 Example 4 12.20 94.5 4.66 92.1 Comparative Example 1 15.85 92.8 12.20 79.2 Comparative Example 2 18.00 91.8 21.50 63.3 Comparative Example 3 13.08 94.1 10.35 82.3 Comparative Example 4 19.33 91.2 23.18 60.5 Comparative Example 5 22.27 89.9 28.33 51.7

[0032] In addition, Figure 2 The total nitrogen removal rate of each different regenerated carbon source is shown in the result graph.

[0033] Table 2 combines Figure 2 As can be seen from the results, in the embodiments of the present application, the regenerated carbon source prepared by using amylase and glucoamylase complex enzyme preparation for enzymatic hydrolysis treatment and membrane filtration with butyric acid Clostridium fermented waste liquid as raw material shows excellent denitrification effect in sewage treatment, which can reduce the total nitrogen content of the initial sewage from 58.64 mg / L to less than 5 mg / L, and the removal rate of total nitrogen reaches 92.5% at most. In addition, the COD value of the sewage can also reach the first-class water quality standard (i.e. ≤15 mg / L).

[0034] In Comparative Examples 1-4, on the basis of each embodiment, only one enzyme preparation or adjusting the type and order of enzyme hydrolysis of enzyme preparation is used, and the regenerated carbon source prepared also shows a certain denitrification effect, but the effect is obviously lower than that of each embodiment. The reason for the above phenomenon may be that the waste liquid used in the present application contains a certain amount of starch components. If only α-amylase is used for enzymatic hydrolysis, it can only break the α-1,4-glycosidic bond in polysaccharides, and the degradation and utilization degree of polysaccharides such as starch in the waste liquid is limited. The saccharifying enzyme can also break the α-1,6-glycosidic bond. Therefore, the complex enzyme hydrolysis of the two can more effectively hydrolyze the polysaccharide components in the waste liquid into small molecule carbon sources that are beneficial to microbial decomposition and utilization. In addition, although stepwise enzymatic hydrolysis can also achieve good results, the enzymatic hydrolysis process is time-consuming, thereby increasing the complexity of the process and reducing the efficiency of enzymatic hydrolysis.

[0035] In addition, although the waste liquid used in the present application contains part of the protein components, it can be removed by membrane treatment. If protease is used for enzymatic hydrolysis, the protein in it will be decomposed into small molecule amino acids, which will make the nitrogen source components in the carbon source too much, not only increasing the difficulty of separation in the later stage, but also increasing the difficulty of denitrification of the system.

[0036] In Comparative Example 5, if the Clostridium paraputrificum fermentation waste liquid is directly used as the regenerated carbon source after simple treatment, it also has a certain denitrification ability because the Clostridium paraputrificum fermentation waste liquid contains 1,3-propanediol, sodium butyrate, sodium acetate and other small molecule carbon source components, and also contains a small amount of magnesium sulfate and other inorganic salt components, which is beneficial to the propagation of denitrifying bacteria to a certain extent. However, because the waste liquid also contains a large amount of protein, starch and other components, it may increase the complexity and difficulty of the system treatment, and therefore the availability of directly using it as a carbon source is not high.

[0037] The above-described embodiments only express the specific implementation of the present application, and the description is more specific and detailed, but it cannot be understood as a limitation on the scope of the patent of the present application. It should be noted that for ordinary skilled persons in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of protection of the present application.

Claims

1. Application of Clostridium butyricum fermentation waste liquor in sewage treatment.

2. Use according to claim 1, wherein The Clostridium butyricum fermentation waste liquor is used as raw material to prepare a renewable carbon source for sewage treatment. The Clostridium butyricum fermentation waste liquor is a waste liquor containing protein, starch, glycerol, 1,3-propanediol, sodium acetate and sodium butyrate produced in the process of Clostridium butyricum fermentation of glycerol to produce 1,3-propanediol.

3. The use according to any one of claims 1 to 2, wherein In the Clostridium butyricum fermentation waste liquor, per 100 parts of the Clostridium butyricum fermentation waste liquor contains 0.5-1.5 parts of protein, 5-12 parts of starch, 5-10 parts of 1,3-propanediol, 3-8 parts of glycerol, 3-5 parts of sodium butyrate, 6-15 parts of sodium acetate, and 0.03-0.05 parts of sulfate.

4. A method for preparing a recycled carbon source for wastewater treatment with Clostridium pasteurianum fermentation broth, characterized by, The steps include the following: (1) Preparation of raw materials: the Clostridium butyricum fermentation waste liquor according to any one of claims 1-3 is fully stirred to serve as raw material for preparation of a renewable carbon source; (2) Enzymatic hydrolysis: a complex enzyme preparation of amylase and glucoamylase is added to the raw material of (1) for enzymatic hydrolysis to obtain an enzymatic hydrolysis liquor; (3) The enzymatic hydrolysis liquor in (2) is subjected to ultrafiltration using an ultrafiltration membrane to obtain a retentate containing effective carbon source; (4) The retentate containing effective carbon source separated in (3) is subjected to multi-effect evaporation and concentration, and then small-molecule nutrient ingredients are added to the concentrated liquor and stirred uniformly to obtain a renewable carbon source; The small molecule nutritional ingredient is selected from the group consisting of histidine, sodium glutamate, leucine, valine, vitamin B1, vitamin B6 12 at least one of the foregoing.

5. The method of claim 4, wherein, In (2), the complex enzyme preparation is added in an amount of 5-50 g per liter of raw material, the enzymatic hydrolysis temperature is 50-70°C, the pH is 4.0-7.0, and the enzymatic hydrolysis time is 60-90 min.

6. The method of claim 4, wherein, In (2), the mass ratio of amylase to glucoamylase is 1-5:

1.

7. The method of claim 4, wherein, The small molecule nutritional ingredient described in (4) is histidine, sodium glutamate, vitamin B 12 .

8. The method of claim 4, wherein, (4) In the middle, 0.05-0.1 parts of histidine, 0.1-0.2 parts of sodium glutamate and 0.1-0.15 parts of vitamin B 12 0.1-0.15 parts are added to 100 parts of the concentrated solution in terms of weight fraction.

9. Application of the renewable carbon source prepared by the method according to any one of claims 4-8 in sewage treatment.

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