Composite carbon source as well as preparation method and application thereof

Abstract

The invention discloses a composite carbon source and a preparation method and application thereof, and belongs to the technical field of carbon source materials and resource utilization. The composite carbon source provided by the invention is prepared from the following raw materials in parts by mass: 50-70 parts of beer wastewater, 1-20 parts of saccharides, 1-20 parts of alcohols, 1-20 parts of acids and 0.05-0.5 part of trace elements. The beer wastewater comes from wastewater generated in a beer production process. Various organic matters rich in the beer wastewater are compounded with saccharides, alcohols, acids and trace elements, the obtained composite carbon source can provide an efficient and stable carbon source for low-carbon-nitrogen-ratio sewage, the requirement of a sewage treatment plant for the carbon source by biological nitrogen removal is met, efficient nitrogen removal is achieved, the beer wastewater can be effectively utilized, and the production cost is reduced. Waste resources are recycled, and good economic value, environmental benefit and social benefit are achieved.

Description

Technical Field

[0001] This invention belongs to the field of carbon source materials and resource utilization technology, and particularly relates to a composite carbon source, its preparation method and application. Background Technology

[0002] Beer wastewater needs to be treated on-site according to relevant standards before being discharged into a wastewater treatment plant for further treatment. Direct discharge without treatment will lead to eutrophication of water bodies and seriously affect the ecological environment. Common treatment processes include activated sludge, biofilm, upflow anaerobic sludge blanket, and anaerobic sequencing batch reactors to remove pollutants from beer wastewater, ensuring that the treated wastewater meets discharge standards. However, these processes consume large amounts of electricity and chemicals, generate significant carbon dioxide emissions and excess sludge. Treating this wastewater as industrial wastewater biologically does not meet the requirements of low-carbon, environmentally friendly, and sustainable development in the long run.

[0004] Beer wastewater is mainly generated during beer production processes such as malting, mashing, fermentation, and bottling. Compared to other industrial wastewater, it is rich in organic matter such as sugars, alcohols, starch, pectin, and yeast residues, exhibiting good biodegradability and lacking toxic or harmful pollutants. However, the COD (Chemical Oxygen Demand) of beer wastewater varies significantly across different production stages, typically fluctuating between 2,000 and 00,000 mg / L. Improper treatment can not only prevent the reuse of waste resources but also fail to reduce the cost of beer wastewater treatment. Summary of the Invention

[0005] In order to overcome at least one of the problems existing in the prior art, one of the objectives of the present invention is to provide a composite carbon source, which combines beer wastewater with sugars, alcohols, acids and trace elements, etc. The resulting composite carbon source can not only achieve good wastewater treatment effect, but also realize the resource utilization of beer wastewater.

[0006] The second objective of this invention is to provide a method for preparing the above-mentioned composite carbon source.

[0007] The third objective of this invention is to provide a wastewater treatment method.

[0008] To achieve the above objectives, the technical solution adopted by the present invention is as follows: The first aspect of the present invention provides a composite carbon source comprising the following raw materials in parts by mass: 50-70 parts beer wastewater, 1-20 parts sugars, 1-20 parts alcohols, 1-20 parts acids, and 0.05-0.5 parts trace elements; wherein the beer wastewater is derived from wastewater generated during the beer production process.

[0009] Compared to other industrial wastewater, beer wastewater is rich in organic matter such as sugars, alcohols, starch, pectin, and yeast residues, exhibiting good biodegradability. It also lacks toxic and harmful pollutants, making it a potential carbon source for denitrification in low-carbon-nitrogen-ratio wastewater. This invention combines beer wastewater with sugars, alcohols, acids, and trace elements to obtain a composite carbon source that provides efficient and stable carbon for low-carbon-nitrogen-ratio wastewater, meeting the carbon source requirements for biological denitrification in wastewater treatment plants, achieving efficient denitrification, and effectively utilizing beer wastewater to achieve waste resource reuse. This invention possesses significant economic, environmental, and social benefits.

[0010] Preferably, the beer wastewater originates from the wastewater generated during the malting and / or saccharification processes in beer production.

[0011] In beer production, the maceration process refers to the conversion of starch into sugars that can be fermented by yeast before the malt grains are fermented, and the saccharification process refers to the conversion of insoluble starch in malt into soluble sugars. The wastewater generated by these two processes contains a large amount of bioavailable organic matter, making it a high-quality raw material for producing composite carbon sources. Furthermore, these two processes do not have the problem of releasing organic nitrogen, making them suitable for use as composite carbon source raw materials. In contrast, the wastewater generated by other process stages (such as fermentation) contains more organic nitrogen, and using it as a composite carbon source raw material would cause the problem of releasing organic nitrogen, which is not conducive to denitrification treatment.

[0012] Preferably, the beer wastewater is obtained by a method comprising the following steps: subjecting the wastewater generated during the beer production process to vortex gravity separation, and taking the supernatant to obtain the beer wastewater.

[0013] Because the wastewater generated during beer production contains a significant amount of microbial residues, lees, and other organic matter, directly using it as a carbon source can affect the denitrification rate and the quality of the composite carbon source product. Therefore, a vortex gravity separation method is used to separate and remove impurities from the wastewater, removing suspended solids such as microbial agent residues and lees. The resulting beer wastewater, suitable for preparing the composite carbon source, is obtained at the top. Furthermore, compared to membrane treatment, traditional high-speed centrifugation, and other solid-liquid separation methods, vortex gravity separation removes larger suspended solids without affecting dissolved organic matter and small organic particles. These dissolved organic matter and small organic particles can be utilized by denitrifying bacteria during microbial denitrification, maximizing the retention of biodegradable substances in the beer wastewater and improving the quality of the composite carbon source product. Therefore, using vortex gravity separation is beneficial for improving the utilization rate of beer wastewater.

[0014] In some specific embodiments of the present invention, the vortex gravity separation is performed in a vortex separator.

[0015] Preferably, in the method for preparing beer wastewater, the rotational speed of the vortex gravity separation is 100~250 r / min; more preferably 120~230 r / min; and even more preferably 150~200 r / min.

[0016] Using an appropriate vortex gravity separation speed is beneficial for removing suspended solids such as bacterial agent residues and distiller's grains from wastewater, while avoiding the removal of dissolved organic matter and tiny organic particles, thus obtaining a composite carbon source that can promote wastewater denitrification efficiency.

[0017] Preferably, the COD content of the beer wastewater is ≥100,000 mg / L; non-limiting examples include 105,000 mg / L, 110,000 mg / L, 130,000 mg / L, 150,000 mg / L, 200,000 mg / L, or 300,000 mg / L.

[0018] Preferably, in the raw materials for preparing the composite carbon source, based on a total of 100 parts of raw materials, the mass fraction of beer wastewater is 52-68 parts; more preferably, it is 55-65 parts.

[0019] Preferably, the sugar includes at least one of glucose, maltose, or sucrose; more preferably, the sugar includes glucose, sucrose, or a combination thereof; even more preferably, the sugar includes glucose and sucrose.

[0020] Preferably, the mass ratio of glucose to sucrose in the sugar is 1:(1~3); more preferably 1:(1.2~2.8); and even more preferably 1:(1.5~2.5).

[0021] Preferably, the COD content of the sugar is 70,000~100,000 mg / L; more preferably 75,000~95,000 mg / L; and even more preferably 80,000~90,000 mg / L.

[0022] Preferably, in the raw materials for preparing the composite carbon source, based on a total of 100 parts of raw materials, the mass fraction of sugar is 3 to 15 parts; more preferably 5 to 10 parts.

[0023] Preferably, the alcohol includes at least one of methanol, ethanol, propanol or butanol; more preferably, the alcohol includes methanol, ethanol or a combination thereof; even more preferably, the alcohol is selected from methanol.

[0024] Preferably, the COD content of the alcohol is 50,000~80,000 mg / L; more preferably 55,000~75,000 mg / L; and even more preferably 60,000~70,000 mg / L.

[0025] Preferably, in the raw materials for preparing the composite carbon source, based on a total of 100 parts of raw materials, the mass fraction of alcohol is 3 to 15 parts; more preferably 5 to 10 parts.

[0026] Preferably, the acid is selected from fatty acids.

[0027] Preferably, the acid includes at least one of acetic acid, propionic acid, butyric acid, or valeric acid; more preferably, the acid includes acetic acid, propionic acid, or a combination thereof; even more preferably, the acid is selected from acetic acid.

[0028] Preferably, the COD content of the acid is 40,000 to 70,000 mg / L; more preferably, it is 45,000 to 65,000 mg / L; and even more preferably, it is 50,000 to 60,000 mg / L.

[0029] Preferably, in the raw materials for preparing the composite carbon source, based on a total of 100 parts of raw materials, the mass fraction of acids is 3 to 15 parts; more preferably, it is 5 to 10 parts.

[0030] Preferably, the trace element includes at least one of copper, manganese, zinc, iodine, magnesium, cobalt, or boron; more preferably, the trace element includes copper, manganese, zinc, iodine, magnesium, cobalt, and boron.

[0031] This invention adds various trace elements suitable for the growth of denitrifying bacteria, which can improve the quality of the composite carbon source obtained from beer wastewater, promote the growth of denitrifying microorganisms, and thus improve the denitrification efficiency of wastewater.

[0032] Preferably, the trace element is added in the form of a soluble salt containing the trace element; more preferably, the soluble salt containing the trace element includes at least one of copper sulfate, manganese chloride, zinc sulfate, potassium iodide, magnesium sulfate, cobalt chloride, or boric acid; even more preferably, the soluble salt containing the trace element includes copper sulfate, manganese chloride, zinc sulfate, potassium iodide, magnesium sulfate, cobalt chloride, and boric acid.

[0033] Preferably, in the raw materials for preparing the composite carbon source, based on a total of 100 parts of raw materials, the mass fraction of trace elements is 0.08 to 0.4 parts; more preferably, it is 0.1 to 0.3 parts.

[0034] Preferably, the composite carbon source comprises the following raw materials in parts by weight: 52-68 parts beer wastewater, 3-15 parts sugars, 3-15 parts alcohols, 3-15 parts acids, and 0.08-0.4 parts trace elements.

[0035] More preferably, the composite carbon source comprises the following raw materials in parts by weight: 55-65 parts beer wastewater, 5-10 parts sugars, 5-10 parts alcohols, 5-10 parts acids, and 0.1-0.3 parts trace elements.

[0036] Preferably, the raw materials for preparing the composite carbon source also include water.

[0037] By adding water, the COD concentration of the composite carbon source can be adjusted to suit different wastewater treatment conditions.

[0038] Preferably, in the raw materials for preparing the composite carbon source, the mass fraction of water is 1 to 40 parts based on a total of 100 parts of raw materials; more preferably, it is 5 to 35 parts; and even more preferably, it is 10 to 30 parts.

[0039] Preferably, the composite carbon source comprises the following raw materials in parts by weight: 50-70 parts beer wastewater, 1-20 parts sugars, 1-20 parts alcohols, 1-20 parts acids, 0.05-0.5 parts trace elements, and 1-40 parts water.

[0040] Preferably, the COD content of the composite carbon source is ≥300,000 mg / L; non-limiting examples include 305,000 mg / L, 310,000 mg / L, 330,000 mg / L, 350,000 mg / L, 400,000 mg / L, 450,000 mg / L, or 500,000 mg / L.

[0041] Preferably, the solid suspended matter content of the composite carbon source is ≤100mg / L; non-limiting examples include 5mg / L, 20mg / L, 50mg / L or 80mg / L.

[0042] A second aspect of the present invention provides a method for preparing the composite carbon source described in the first aspect of the present invention, comprising the following steps: mixing the various raw materials to obtain the composite carbon source.

[0043] In some specific embodiments of the present invention, the preparation method of the composite carbon source includes the following specific steps: sugars, alcohols, acids and trace elements are added sequentially to beer wastewater, and the composite carbon source is obtained after mixing.

[0044] In some other specific embodiments of the present invention, when the raw materials for preparing the composite carbon source also include water, the preparation method of the composite carbon source includes the following specific steps: adding sugars, alcohols, acids, trace elements and water in sequence to beer wastewater, and mixing them to obtain the composite carbon source.

[0045] A third aspect of the present invention provides an application of the composite carbon source as described in the first aspect of the present invention in wastewater treatment.

[0046] In some specific embodiments of the present invention, the wastewater is wastewater with a low carbon-to-nitrogen ratio.

[0047] The beneficial effects of this invention are: This invention utilizes the various organic substances abundant in beer wastewater, and combines them with sugars, alcohols, acids and trace elements to obtain a composite carbon source that can provide an efficient and stable carbon source for wastewater with a low carbon-to-nitrogen ratio, meeting the carbon source requirements of biological denitrification in wastewater treatment plants, achieving efficient denitrification, and effectively utilizing beer wastewater to achieve waste resource reuse, thus possessing good economic value, environmental benefits and social benefits. Attached Figure Description

[0048] Figure 1 The wastewater treatment reactor apparatus is shown in Examples 1-2 of this invention.

[0049] Figure 2 The following is an example of the application of this invention: the change in total nitrogen concentration in the influent and effluent.

[0050] Figure 3 The following is an example of the change in COD concentration in the effluent of Application Example 1 of this invention.

[0051] Figure 4 The following is an example of the application of the present invention: the change in total nitrogen concentration in the influent and effluent.

[0052] Figure 5 The following is an example of the change in COD concentration in the effluent of application example 2 of the present invention. Detailed Implementation

[0053] The following specific embodiments further illustrate the content of the present invention in detail. It should also be understood that the following embodiments are only for further explanation of the present invention and should not be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art based on the principles described herein are all within the scope of protection of the present invention. The specific process parameters, etc., in the following examples are merely examples within a suitable range; that is, those skilled in the art can make selections within a suitable range based on the description herein, and are not intended to be limited to the specific data in the examples below. Unless otherwise specified, the raw materials, reagents, or apparatus used in the following embodiments and comparative examples can be obtained from conventional commercial sources or by existing known methods.

[0054] Example 1 A composite carbon source derived from beer wastewater comprises the following raw materials in weight percentages: 60% beer wastewater, 10% sugars, 5% alcohols, 5% acids, 0.1% trace elements, and the remainder being water. The beer wastewater originates from the malting and / or saccharification processes during beer production. Specifically, it is obtained through the following steps: The wastewater generated during beer production is separated in a vortex separator at a speed controlled at 150-200 r / min to remove suspended solids such as microbial agent residues and lees. The wastewater is collected at the upper overflow pipe, with a COD equivalent of 108 kg / t. Sugars are a mixture of glucose and by-product sucrose at a mass ratio of 1:2, with a COD equivalent of 86 kg / t. Alcohols are methanol, with a COD equivalent of 63 kg / t. Acids are acetic acid, with a COD equivalent of 51 kg / t. Trace elements include copper sulfate, manganese chloride, zinc sulfate, potassium iodide, magnesium sulfate, cobalt chloride, and boric acid, with a total trace element content of 1 kg / t.

[0055] The preparation of the above-mentioned composite carbon source includes the following steps: Beer wastewater is added to a reaction vessel, followed by the sequential addition of sugars, alcohols, acids, trace elements, and water, and the mixture is stirred thoroughly. The reaction process is monitored using online temperature, pH, COD concentration, and gas analyzers. The qualified product obtained after the reaction is complete is the composite carbon source. Online pH and COD concentration analyzers are used to monitor the product. If the pH value does not meet the discharge requirements, acidic or alkaline raw materials can be added for adjustment. If the COD concentration does not meet the discharge requirements, alcohols, sugars, fatty acids, and other raw materials can be added for adjustment to ensure product stability.

[0056] The COD equivalent of the composite carbon source obtained in this example is 308 kg / t.

[0057] Application Example 1 The composite carbon source prepared in Example 1 was applied to wastewater treatment. Specifically, an A2O+MBR membrane effluent process was used to simulate the entire wastewater treatment process, and the denitrification effect of the composite carbon source based on beer wastewater was evaluated. The reactor had a daily treatment capacity of approximately 100L. The device was as follows: Figure 1 As shown in the figure. The sludge in this example was taken from the secondary sedimentation tank of a wastewater treatment plant in Shenzhen, maintaining a sludge concentration of approximately 4000 mg / L in the system. The influent was low C / N ratio domestic sewage. Potassium nitrate was used to control the initial nitrate concentration at around 30 mg / L. After adding a composite carbon source, the initial C / N ratio was controlled at 6. The total nitrogen concentration of the reactor effluent was measured daily. The experimental results are shown in the figure. Figure 2 The COD concentration of the reactor effluent was measured daily, and the experimental results are shown below. Figure 3 .

[0058] from Figures 2-3As can be seen from the experimental results, during the entire experiment, the use of the produced composite carbon source for biological denitrification can stably control the total nitrogen in the effluent to within 10 mg / L and the COD concentration to within 40 mg / L. This indicates that the composite carbon source produced based on beer wastewater in Example 1 has a good denitrification effect and can be used to promote denitrification of domestic sewage with low carbon-to-nitrogen ratio.

[0059] Example 2 A composite carbon source derived from beer wastewater differs from Example 1 in the mass percentage of each raw material. In this example, the composition is: beer wastewater 60%, sugars 5%, alcohols 10%, acids 10%, trace elements 0.3%, and the remainder water. The specific raw material types and preparation method are the same as in Example 1. The COD equivalent of the composite carbon source obtained in this example is 422 kg / t.

[0060] Application Example 2 The composite carbon source prepared in Example 2 was applied to wastewater treatment. The wastewater in this example came from leachate from a landfill in Shenzhen. The specific treatment steps were the same as in Application Example 1. The total nitrogen concentration of the reactor effluent was measured daily, and the experimental results are shown below. Figure 4 The COD concentration of the reactor effluent was measured daily, and the experimental results are shown below. Figure 5 .

[0061] from Figures 4-5 As can be seen, during the experiment, the total nitrogen concentration in the influent was between 240 and 360 mg / L, while the total nitrogen in the effluent steadily decreased to below 50 mg / L, and the COD concentration was basically controlled below 90 mg / L, meeting the effluent discharge requirements. This indicates that the composite carbon source produced from beer wastewater in Example 1 has a good denitrification effect and can be used to promote the deep denitrification treatment of landfill leachate.

[0062] Application Example 3 The denitrification effect of the composite carbon source prepared in the embodiments of the present invention was verified using a sequencing batch reactor (SBR). Using methanol, glucose, starch, and acetic acid as single carbon sources as controls, the denitrification rates of the composite carbon sources prepared in Examples 1 and 2 were compared. The specific steps are as follows: First, activated sludge retrieved from a wastewater treatment plant in Shenzhen was added to six identical SBR reactors. Before being added to the reactors, the sludge was rinsed three times with a 0.5 g / L NaHCO3 solution to remove residual nitrogenous compounds and organic matter, while maintaining the sludge concentration in the SBR reactors at 3.5 g / L (MLSS). Then, potassium nitrate was added to each reactor to achieve a nitrate concentration of 30 mg / L. Methanol, glucose, starch, acetic acid, and the composite carbon source from Examples 1 and 2 were added to each SBR reactor, respectively, maintaining a carbon-to-nitrogen ratio of 6:1 in each reactor. Stirring was started, and 5 mL samples were taken from each SBR reactor every 30 minutes for nitrate and nitrite concentration analysis.

[0063] In the denitrification process, the number of electrons required to reduce 1g of nitrite is the same as the number required to reduce 0.6g of nitrate. Therefore, NO is used. x - -N is used to evaluate the nitrogen removal performance of different carbon sources (NO). x - -N=NO3 - -N+0.6NO2 - -N). Denitrification rates (mg NO) for different carbon sources x - -N / (gMLSS·h)) with time as the x-axis, NO x - Using -N concentration as the ordinate, a linear regression calculation is performed according to the following formula:

[0064] The results are shown in Table 1 below: Table 1. Comparison of denitrification rates between composite carbon sources and single carbon sources in Examples 1-2

[0065] As shown in Table 1, the denitrification rates of the composite carbon sources in Examples 1 and 2 are significantly better than those of glucose and starch, slightly lower than those of acetic acid, and close to those of methanol. However, methanol is a flammable and explosive hazardous chemical, requiring strict adherence to safety regulations during daily use and storage, posing certain safety hazards. Acetic acid is a Class B hazardous chemical, and its on-site use produces a noticeable irritating odor; its market price fluctuates significantly, and large-scale addition would substantially increase the operating costs of wastewater treatment plants. The composite carbon source prepared using the embodiments of this invention can overcome these drawbacks and significantly improve the denitrification rate.

[0066] Based on the experimental results of the above embodiments and application examples, it can be found that the composite carbon source obtained from beer wastewater in this invention can be used to enhance the biological denitrification of domestic sewage and landfill leachate with low carbon-to-nitrogen ratio, and the denitrification stability is good, showing great potential for large-scale application.

[0067] In summary, this invention utilizes the various organic substances abundant in beer wastewater, combining them with sugars, alcohols, acids, and trace elements to obtain a composite carbon source that can provide an efficient and stable carbon source for wastewater with a low carbon-to-nitrogen ratio. This meets the carbon source requirements for biological denitrification in wastewater treatment plants, achieving efficient denitrification. Furthermore, it effectively utilizes beer wastewater, realizing the reuse of waste resources, and possesses good economic, environmental, and social benefits.

Claims

1. A composite carbon source, characterized in that, The preparation materials include the following parts by weight: 50-70 parts beer wastewater, 1-20 parts sugars, 1-20 parts alcohols, 1-20 parts acids, and 0.05-0.5 parts trace elements; The beer wastewater comes from the wastewater generated during the beer production process.

2. The composite carbon source according to claim 1, characterized in that, The beer wastewater originates from the malting and / or saccharification processes during beer production.

3. The composite carbon source according to claim 1, characterized in that, The beer wastewater is obtained by a method including the following steps: vortex gravity separation of wastewater generated during beer production, and taking the supernatant to obtain the beer wastewater.

4. The composite carbon source according to claim 3, characterized in that, The rotational speed of the vortex gravity separation is 150~200 r / min.

5. The composite carbon source according to claim 1, characterized in that, The COD content of the beer wastewater is ≥100,000 mg / L; And / or, the COD content of the sugar is 70,000~100,000 mg / L; And / or, the COD content of the alcohol is 50,000~80,000 mg / L; And / or, the COD content of the acid is 40,000~70,000 mg / L.

6. The composite carbon source according to claim 1, characterized in that, The carbohydrate compound includes at least one of glucose, maltose, or sucrose; And / or, the alcohols include at least one of methanol, ethanol, propanol or butanol; And / or, the fatty acids include at least one of acetic acid, propionic acid, butyric acid or valeric acid; And / or, the trace element includes at least one of copper, manganese, zinc, iodine, magnesium, cobalt or boron.

7. The composite carbon source according to claim 1, characterized in that, Water is also included as a raw material in the preparation.

8. The composite carbon source according to any one of claims 1 to 7, characterized in that, The COD content of the composite carbon source is ≥300000 mg / L; And / or, the solid suspended matter content of the composite carbon source is ≤100mg / L.

9. A method for preparing a composite carbon source as described in any one of claims 1 to 8, characterized in that, Includes the following steps: The various raw materials are mixed to obtain the composite carbon source.

10. The application of a composite carbon source as described in any one of claims 1 to 8 in wastewater treatment.

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