Mixed carbon source and method for producing the same

Abstract

The present application provides a mixed carbon source and a preparation method thereof, the mixed carbon source comprising: a solid carbon source comprising at least one of agricultural products and crop wastes; a liquid carbon source comprising at least one of alcohol compounds, organic acid compounds and sugar compounds; activated sludge; and a catalyst comprising a salt or an oxide of a transition metal as an active component. The mixed carbon source can reduce the cost of sewage treatment and improve the denitrification efficiency.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and more specifically, to a mixed carbon source and a method for preparing the mixed carbon source. Background Technology

[0002] With the changes in modern people's lifestyles and the increase in water consumption, urban domestic sewage is gradually showing a trend of low carbon source. The carbon source in sewage is insufficient to meet the growth requirements of denitrifying microorganisms, which limits the denitrification process and usually requires the addition of external carbon sources.

[0003] Short-chain alcohols such as methanol and ethanol are relatively expensive and classified as hazardous chemicals, posing safety risks during their production, transportation, storage, and use, thus limiting their large-scale industrial application. Acetic acid, due to its strong odor, high cost, and corrosiveness, has also not been widely adopted in the market. Furthermore, sodium acetate (generally sodium acetate trihydrate) contains water of crystallization, resulting in a low hydrocarbon content available for denitrification, and it is prone to crystallization during application. Compared to the aforementioned carbon sources, glucose offers relatively high cost-effectiveness; however, it is prone to nitrite accumulation and sludge bulking during use. Using solid carbon sources as external carbon sources presents challenges such as slow carbon release and secondary pollution.

[0004] Therefore, there are significant limitations when using a single carbon source. Developing a low-cost and high-efficiency composite denitrification carbon source is of great significance for reducing wastewater treatment costs and improving denitrification efficiency. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of the prior art and provide a mixed carbon source that can reduce wastewater treatment costs and improve denitrification efficiency, as well as a method for preparing the mixed carbon source.

[0006] On one hand, the mixed carbon source according to an exemplary embodiment may include: a solid carbon source; a liquid carbon source, including at least one of alcohols, organic acids and sugars; activated sludge; and a catalyst, including a salt or oxide of a transition metal as an active component.

[0007] According to an exemplary embodiment, a solid carbon source may include at least one of agricultural products and agricultural waste.

[0008] According to an exemplary embodiment, agricultural products may include tuber-based agricultural products, and agricultural waste may include at least one of the following: crop straw, core, husk, and residue.

[0009] According to an exemplary embodiment, agricultural products may include at least one of cassava, potato, and sweet potato.

[0010] According to an exemplary embodiment, agricultural waste may include at least one of corn cobs, corn stalks, wheat stalks, peanut shells, soybean stalks, cotton stalks, and sugarcane bagasse.

[0011] According to an exemplary embodiment, the solid carbon source can be in the form of powder, wherein the particle size of the powdered solid carbon source is 100 to 500 mesh.

[0012] According to an exemplary embodiment, the weight ratio of solid carbon sources can be in the range of 10% to 30% based on the total weight of the mixed carbon sources.

[0013] According to an exemplary embodiment, the liquid carbon source may include at least one of methanol, ethanol, ethylene glycol, sodium acetate, sodium propionate, glucose, sucrose, and soluble starch.

[0014] According to an exemplary embodiment, ethylene glycol can be waste refrigerant recovered from wind turbines.

[0015] According to an exemplary embodiment, the weight ratio of liquid carbon sources can be in the range of 40% to 79% based on the total weight of the mixed carbon sources.

[0016] According to an exemplary embodiment, the activated sludge can be derived from the sedimentation zone of a wastewater treatment facility, and its moisture content can be in the range of 50% to 90%.

[0017] According to an exemplary embodiment, the weight ratio of activated sludge can be in the range of 10% to 20% based on the total weight of the mixed carbon sources.

[0018] According to an exemplary embodiment, the catalyst can be a waste catalyst from a wastewater or exhaust gas treatment system.

[0019] According to an exemplary embodiment, the transition metal may include at least one of Fe, Cu, Mn, Mo, Ni, Zn, Co, and W.

[0020] According to an exemplary embodiment, the weight ratio of the active component in the catalyst can be in the range of 0.02% to 1.2% based on the total weight of the mixed carbon sources.

[0021] According to an exemplary embodiment, based on the total weight of the mixed carbon sources, the catalyst may further include a support material in the range of 0.98% to 8.8% by weight, wherein the support material may include at least one of magnesium oxide, aluminum oxide, and calcium oxide.

[0022] On the other hand, the method for preparing a mixed carbon source according to an exemplary embodiment may include: step 1: mixing a solid carbon source, a liquid carbon source and activated sludge evenly and adding them to a ball rolling mill; step 2: adding a catalyst to the ball rolling mill for rolling to obtain an initial mixed carbon source; and step 3: placing the initial mixed carbon source in a light-proof place for a predetermined period of time to obtain a mixed carbon source.

[0023] According to an exemplary embodiment, step 1 may include: thoroughly stirring the solid carbon source and activated sludge until they are uniformly mixed; and diluting the liquid carbon source and spraying it onto the surface of the mixture of solid carbon source and activated sludge, and stirring it uniformly. In step 2, each component in the ball rolling machine can be rolled into granules. In step 3, the initial mixed carbon source may be placed in a cool place for 1 to 3 days to obtain a mixed carbon source.

[0024] According to an exemplary embodiment, step 3 may further include spraying liquid onto the surface of the initial mixed carbon source at a predetermined time interval to keep the initial mixed carbon source moist.

[0025] According to an exemplary embodiment, based on the total weight of the mixed carbon sources, the weight ratio of solid carbon sources can be in the range of 10% to 30%, the weight ratio of liquid carbon sources can be in the range of 40% to 79%, the weight ratio of activated sludge can be in the range of 10% to 30%, and the weight ratio of active ingredients included in the catalyst can be in the range of 0.02% to 1.2%.

[0026] The technical concept of this invention has been briefly described above. This invention develops a mixed carbon source and its preparation method. On one hand, the microorganisms present in this mixed carbon source can rapidly engage in biological reactions with microorganisms in the wastewater system, avoiding the problem of long utilization time of solid carbon sources. On the other hand, this mixed carbon source contains some readily available carbon sources, ensuring that the nutrients required for microbial metabolism are met. After the readily available carbon sources are used up, a portion of solid carbon sources remains that can be utilized. Therefore, this mixed carbon source can rapidly and continuously provide carbon sources to the wastewater treatment system. Furthermore, this mixed carbon source can reduce the reagent costs of carbon source agents in water treatment plants. In addition, the catalyst can provide inorganic nutrients and trace elements required for microbial metabolism, enabling better biochemical processes such as microbial reactions, reproduction, and metabolism. Detailed Implementation

[0027] In the following description, numerous specific details are set forth for purposes of explanation in order to provide a thorough understanding of various embodiments or implementations of the invention. As used herein, "embodiment" and "exemplary embodiment" are interchangeable terms and are non-limiting examples of apparatus or methods employing one or more of the inventive concepts disclosed herein. However, it will be apparent that various embodiments may be practiced without these specific details or with one or more equivalent arrangements. Furthermore, the various embodiments may differ, but are not necessarily exclusive.

[0028] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure is a part. Terms (such as those defined in a general dictionary) shall be interpreted as having a meaning consistent with their meaning in the context of the relevant field, and shall not be interpreted in an idealized or overly formal sense, unless expressly defined herein.

[0029] This invention provides a mixed carbon source and its preparation method. The mixed carbon source can meet the metabolic and growth needs of microorganisms, can be immediately utilized, and can provide a continuous carbon source for wastewater treatment systems. Furthermore, this mixed carbon source can reduce wastewater treatment costs and solve the problems of sludge and waste catalyst treatment and disposal, and can be widely used in municipal and domestic wastewater treatment.

[0030] The mixed carbon source according to the present invention will now be described in detail with reference to exemplary embodiments.

[0031] The mixed carbon source according to an exemplary embodiment may include: a solid carbon source; a liquid carbon source, including at least one of alcohols, organic acids, and sugars; activated sludge; and a catalyst, including a salt or oxide of a transition metal as an active component.

[0032] According to an exemplary embodiment, the solid carbon source may include at least one of agricultural products and agricultural waste. Agricultural products refer to products of agricultural production. In embodiments, agricultural products may be inexpensive agricultural products, including tuber-based products such as cassava, potatoes, and sweet potatoes, but are not limited thereto. According to an exemplary embodiment, agricultural waste refers to substances discarded throughout the agricultural production process. For example, agricultural waste may include at least one of crop stalks, cobs, husks, and residues. In embodiments, agricultural waste may include at least one of corn cobs, corn stalks, wheat stalks, peanut shells, soybean stalks, cotton stalks, and bagasse, but is not limited thereto. In embodiments, agricultural waste is preferably used as the solid carbon source, and corn cobs are preferred.

[0033] According to an exemplary embodiment, the solid carbon source can be in powder form, but the embodiments are not limited thereto. The particle size of the powdered solid carbon source can be in the range of approximately 100 to 500 mesh. The solid carbon source can be in a dry state.

[0034] According to an exemplary embodiment, agricultural products and / or crop waste, as solid carbon sources, can be rich in vitamins and inorganic nutrients such as K, Mg, Ca, S, and Na, which can promote the growth, development, metabolism, and enzyme synthesis of denitrifying microorganisms, thereby improving denitrification efficiency.

[0035] This invention primarily uses agricultural products and / or agricultural waste as a solid carbon source. When adding the solid carbon source to a wastewater treatment system, it needs to be prepared to be easily utilized by microorganisms. Because the carbon release rate of solid carbon sources is slow, it is necessary to extend the contact time between the wastewater and the carbon source, or to allow for sufficient fermentation before adding the solid carbon source to the wastewater treatment system; otherwise, the denitrification and phosphorus removal efficiency of agricultural products and / or agricultural waste as a carbon source will be reduced. Furthermore, agricultural products and / or agricultural waste themselves contain nitrogen and phosphorus, which will also release nitrogen and phosphorus when used as a carbon source, which is detrimental to denitrification and phosphorus removal. Therefore, a reasonable proportion of agricultural products and / or agricultural waste in the mixed carbon source structure needs to be designed to avoid the drawbacks of using a single solid carbon source, thereby better improving the function of the mixed carbon source.

[0036] According to an exemplary embodiment, the weight ratio of solid carbon sources can be in the range of approximately 10% to 30% based on the total weight of the mixed carbon sources. When the content of solid carbon sources is less than 10%, it will cause problems such as an increase in liquid carbon sources and higher reagent processing costs. When the content of solid carbon sources is greater than 30%, it will cause problems such as a decrease in denitrification rate, an increase in nitrogen and phosphorus release, and a greater pressure on the system for nitrogen and phosphorus removal.

[0037] According to an exemplary embodiment, the addition of a solid carbon source to a wastewater treatment system mainly involves two reaction steps. The first step is to release soluble carbon source, which is a type of carbon source that is easily utilized by microorganisms. The second step is to release the remaining insoluble carbon source, which requires the action of microorganisms to be further decomposed, thereby playing its role as a carbon source. Therefore, in the mixed carbon source according to the exemplary embodiment, the solid carbon source plays the following roles: (1) It can provide a carbon source for heterotrophic denitrifying bacteria without the need for additional soluble organic matter; (2) It can serve as a biological carrier, where microorganisms gradually form a biofilm on its surface, which has a certain retention effect on the microorganisms in the system and increases the amount of microorganisms in the system; (3) The formation of a biofilm on the surface of the solid carbon source can slow down the carbon source release rate of the solid carbon source, which can reduce the risk of secondary pollution caused by the rapid release of soluble carbon in the solid carbon source and extend the service life of the solid carbon source.

[0038] According to an exemplary embodiment, the alcohol compound used as a liquid carbon source may include at least one of methanol, ethanol, ethylene glycol, etc. The organic acid compound used as a liquid carbon source may include at least one of sodium acetate, sodium propionate, etc. The sugar compound used as a liquid carbon source may include at least one of glucose, sucrose, etc., but is not limited thereto. In an embodiment, ethylene glycol may be derived from waste refrigerant recovered from a wind turbine.

[0039] In this embodiment, the crude waste coolant from wind turbines can be collected on-site at the wind farm and transported to a designated waste coolant purification facility. The collected crude waste coolant can be collected in a storage tank and filtered to remove obvious impurities, thus obtaining raw material for a mixed carbon source, which is then stored for later use. The annual production of waste coolant is approximately 400 tons. Using waste coolant as a raw material to prepare a liquid carbon source can effectively reduce the cost of waste coolant treatment and disposal, while also lowering the preparation cost of the mixed carbon source.

[0040] According to an exemplary embodiment, the weight ratio of liquid carbon source can be in the range of approximately 40% to 79% based on the total weight of the mixed carbon sources. Liquid carbon source is a soluble carbon source. The addition of liquid carbon source can rapidly remove nitrogenous substances, but its addition cost is high, and the dosage is difficult to control. When the liquid carbon source content is less than 40%, incomplete denitrification is likely to occur. When the liquid carbon source content is greater than 79%, some carbon source will remain, leading to secondary pollution. Furthermore, long-term addition of a single carbon source during the actual operation of wastewater treatment plants can result in incomplete denitrification, poor phosphorus release capacity, and sludge bulking.

[0041] According to an exemplary embodiment, the activated sludge can originate from the sedimentation zone of a wastewater treatment facility, such as, but not limited to, a sedimentation tank in a wastewater treatment plant. The moisture content of the activated sludge needs to be controlled within the range of approximately 50% to 90%, preferably within the range of approximately 70% to 80%. According to an exemplary embodiment, the weight ratio of activated sludge can be within the range of approximately 10% to 20% based on the total weight of the mixed carbon source. Wastewater treatment plants often employ activated sludge processes, resulting in the discharge of large quantities of activated sludge and incurring significant sludge disposal costs. Adding the aforementioned amount of activated sludge to the mixed carbon source can, on the one hand, increase the microbial content in the mixed carbon source, improve the nitrification rate of the carbon source in the wastewater treatment system, and enhance the adaptability of the microorganisms; on the other hand, the moisture in the activated sludge facilitates the release of solid carbon source into soluble carbon source.

[0042] According to an exemplary embodiment, the catalyst may include a salt or oxide of a transition metal as an active component, wherein the transition metal may include at least one selected from Fe, Cu, Mn, Mo, Ni, Zn, Co, and W.

[0043] According to an exemplary embodiment, the catalyst can be a particulate catalyst with a particle size in the range of approximately 3 mm to 15 mm.

[0044] According to an exemplary embodiment, the catalyst can provide trace elements required for microbial metabolism. For example, the active component in the catalyst can act as a supplier of trace elements required for microbial metabolism, thereby enabling better biochemical processes such as microbial reactions, reproduction, and metabolism. Based on the total weight of the mixed carbon sources, the weight ratio of the active component in the catalyst is in the range of approximately 0.02% to approximately 1.2%. When the weight ratio of the active component is less than 0.02%, the trace elements supplied by the active component will be insufficient and will not promote better microbial growth. When the weight ratio of the active component is greater than 1.2%, excessive trace elements will inhibit microbial growth and hinder the biochemical processes such as microbial reactions, reproduction, and metabolism.

[0045] According to an exemplary embodiment, the catalyst is preferably a supported catalyst, that is, the catalyst may further include a support material to provide nutrients to the microorganisms and may also serve as a carrier for microbial growth. In the embodiments, the support material may be at least one of materials such as magnesium oxide, aluminum oxide, and calcium oxide, but the embodiments are not limited thereto.

[0046] According to an exemplary embodiment, the weight ratio of the support material can be in the range of approximately 0.98% to approximately 8.8% based on the total weight of the mixed carbon sources. In this case, the weight ratio of the catalyst, including the active component and the support material, can be in the range of approximately 1% to approximately 10% based on the total weight of the mixed carbon sources.

[0047] According to an exemplary embodiment, the catalyst is preferably a spent catalyst, more preferably a spent catalyst from a wastewater or waste gas treatment system, such as a spent ozone catalytic oxidation catalyst. The pores of the support material in the spent catalyst can adsorb and saturate organic pollutants, which can then be released gradually into the wastewater treatment system as a slow-release carbon source, thereby extending the lifespan of the mixed carbon source. Furthermore, the active components in the spent catalyst are typically deactivated due to occupied catalytic sites, metal accumulation, etc.; however, such a structure can provide a good support for the growth of microorganisms. Therefore, compared to unused catalysts, spent catalysts can achieve better denitrification results.

[0048] According to the exemplary embodiment, when the mixed carbon source is not added to the wastewater treatment system, the activated sludge contains a large number of microorganisms. The catalyst provides the trace elements necessary for microbial growth. The microorganisms can reproduce using the liquid and easily released carbon sources present in the mixed carbon source itself. Simultaneously, the solid carbon source and catalyst provide a good carrier for microbial reproduction. Furthermore, the microorganisms in the activated sludge can nitrify and decompose carbon sources in the solid carbon source that are not easily released into the liquid, making the mixed carbon source easier and faster to utilize when added to the wastewater treatment system.

[0049] According to the exemplary embodiment, the components in the mixed carbon source can be broadly classified into three categories based on their properties: carbon source, additives, and trace elements.

[0050] Carbon sources can be primarily liquid, supplemented by solid carbon sources. When this carbon source is added to a wastewater biological treatment system, existing microorganisms can rapidly engage in biological reactions, avoiding the long utilization time of solid carbon sources. Furthermore, the mixed carbon source still contains some readily available carbon, ensuring that the nutrients required for microbial metabolism are met. After the readily available carbon source is depleted, a portion of solid carbon remains, providing a continuous carbon supply to the wastewater treatment system. Additionally, reducing the amount of liquid carbon source used and using solid carbon sources primarily derived from agricultural and / or crop waste can lower the cost of carbon source chemicals in wastewater treatment plants.

[0051] Additives may include microbial additives present in activated sludge and vitamin additives derived from solid carbon sources. Activated sludge provides microorganisms and also acts as a binder in the carbon source preparation process. The vitamins naturally present in the solid carbon source provide nutrients for biochemical processes such as microbial metabolism.

[0052] Trace elements may include inorganic nutrients and / or trace elements provided by the catalyst as required for microbial metabolism. The catalyst is preferably a supported catalyst, wherein the support material can constitute a large proportion, providing nutrients for microbial metabolism. The active component can constitute a small proportion, providing trace elements for microbial metabolism, thus enabling better biochemical processes such as microbial reactions, reproduction, and metabolism. Furthermore, the catalyst is preferably a spent catalyst used in wastewater and waste, which can further improve wastewater treatment efficiency.

[0053] The mixed carbon source formulation according to the exemplary embodiment is complete, reasonable, and inexpensive to prepare. The granular form of the mixed carbon source also facilitates transportation and use. Furthermore, when the mixed carbon source according to the exemplary embodiment is added to a biochemical system for wastewater treatment, the powder layer on the outer surface of the mixed carbon source can be rapidly dispersed and dissolved.

[0054] The preparation method of the mixed carbon source according to the present invention will be described in detail below with reference to exemplary embodiments.

[0055] The method for preparing a mixed carbon source according to an exemplary embodiment may include: step 1: mixing a solid carbon source, a liquid carbon source and activated sludge evenly and adding them to a ball rolling mill; step 2: adding a catalyst to the ball rolling mill for rolling to obtain an initial mixed carbon source; and step 3: placing the initial mixed carbon source in a light-proof place for a predetermined period of time to obtain a mixed carbon source.

[0056] According to an exemplary embodiment, step 1 may include: thoroughly stirring the solid carbon source and activated sludge until they are evenly mixed; and diluting the liquid carbon source and spraying it onto the surface of the mixture of solid carbon source and activated sludge, and stirring it evenly.

[0057] According to an exemplary embodiment, in step 2, the components in the ball rolling machine can be rolled into granules.

[0058] According to an exemplary embodiment, step 3 may include placing the initial mixed carbon source in a cool place for 1 to 3 days to obtain a mixed carbon source. In an embodiment, step 3 may involve placing the initial mixed carbon source in a cool place to nourish it for approximately 1 to 3 days to obtain a mixed carbon source. In an embodiment, step 3 may involve spraying liquid (e.g., water) onto the surface of the initial mixed carbon source daily to keep it moist. In an embodiment, step 3 may involve placing the initial carbon source in a cool place, spraying water onto the surface of the initial mixed carbon source at least morning and evening daily to keep it moist, and stirring thoroughly, repeating the above operations for approximately 1 to 3 days to obtain the final mixed carbon source. The goal of step 3 is to utilize the microorganisms naturally present in the sludge, further multiplying them with the help of carbon sources that are easily absorbed by nitrification, so that when the carbon source is added to the biological system, the microorganisms can quickly adapt to and nitrify the carbon source, improving the system's reaction efficiency and shortening the system start-up and adaptation cycle.

[0059] The above description, in conjunction with exemplary embodiments, details the mixed carbon source and its preparation method according to the present invention. Some descriptions of well-known technologies have been omitted to more fully convey the inventive concept to those skilled in the art.

[0060] The beneficial effects of the present invention will be more clearly understood below in conjunction with embodiments and comparative embodiments according to the present invention.

[0061] Preparation and effect evaluation of mixed carbon sources

[0062] [Example 1]

[0063] Step 1: Select corn cobs, peanut shells, and cassava (weight ratio 1:1:1) as solid carbon sources with a particle size of 300 mesh, accounting for 25% of the total weight of the mixed carbon sources; select ethanol, sodium acetate, and glucose (weight ratio 1:1:1) as liquid carbon sources, accounting for 60% of the total weight of the mixed carbon sources; select activated sludge with a moisture content of 70%, accounting for 10% of the total weight of the mixed carbon sources; thoroughly mix the above solid carbon sources and activated sludge until uniform; then, dilute the liquid carbon source and spray it onto the surface of the mixture of solid carbon sources and activated sludge, and stir evenly.

[0064] Step Two: Select discarded ozone catalyst from the wastewater treatment system (alumina as the carrier material, iron oxide and manganese oxide as the active components). Based on the total weight of the mixed carbon source, its weight ratio is 5%. Roll the catalyst thoroughly with the material from Step One to obtain an initial mixed carbon source. Place the initial mixed carbon source in a cool place and spray clean water on its surface at least morning and evening every day to keep it moist. Stir well and repeat the above operation for approximately 3 days to obtain the final mixed carbon source 1.

[0065] [Example 2]

[0066] Step 1: Select corn stalks, wheat stalks, and cotton stalks (weight ratio 1:1:1) as solid carbon sources with a particle size of 200 mesh, accounting for 30% of the total weight of the mixed carbon sources; select ethanol, sodium acetate, and glucose (weight ratio 1:1:1) as liquid carbon sources, accounting for 45% of the total weight of the mixed carbon sources; select activated sludge with a moisture content of 70%, accounting for 20% of the total weight of the mixed carbon sources; thoroughly mix the above solid carbon sources and activated sludge until uniform; then, dilute the liquid carbon source and spray it onto the surface of the mixture of solid carbon sources and activated sludge, and stir evenly.

[0067] Step Two: Select discarded ozone catalyst from the wastewater treatment system (alumina as the carrier material, iron oxide and manganese oxide as the active components). Based on the total weight of the mixed carbon source, its weight ratio is 5%. Roll it thoroughly with the material from Step One to obtain an initial mixed carbon source. Place the initial mixed carbon source in a cool place and spray clean water on its surface at least morning and evening every day to keep it moist. Stir it evenly and repeat the above operation for about 3 days to obtain the final mixed carbon source 2.

[0068] [Example 3]

[0069] Step 1: Select corn cobs, peanut shells, and cassava (weight ratio 1:1:1) as solid carbon sources with a particle size of 300 mesh, accounting for 25% of the total weight of the mixed carbon sources; select ethanol, sodium acetate, and glucose (weight ratio 1:1:1) as liquid carbon sources, accounting for 60% of the total weight of the mixed carbon sources; select activated sludge with a moisture content of 70%, accounting for 10% of the total weight of the mixed carbon sources; thoroughly mix the above solid carbon sources and activated sludge until uniform; then, dilute the liquid carbon source and spray it onto the surface of the mixture of solid carbon sources and activated sludge, and stir evenly.

[0070] Step Two: Select unused ozone catalyst from the wastewater treatment system (alumina as the carrier material, iron oxide and manganese oxide as the active components). Based on the total weight of the mixed carbon source, its weight ratio is 5%. Roll the catalyst thoroughly with the material from Step One to obtain an initial mixed carbon source. Place the initial mixed carbon source in a cool place and spray clean water on its surface at least morning and evening every day to keep it moist. Stir well and repeat the above operation for approximately 3 days to obtain the final mixed carbon source 3.

[0071] [Comparative Example 1]

[0072] Ethanol, sodium acetate, and glucose (in a weight ratio of 1:1:1) were selected as liquid carbon sources, with a weight ratio of 100%, to obtain mixed carbon source 4.

[0073] The mixed carbon sources 1 to 4 obtained in Examples 1 to 3 and Comparative Example 1 were respectively added to the simulated wastewater treatment plant A. 2 In the O treatment system, the carbon source dosage is 20 g / L. The influent and effluent water quality without carbon source are shown in Table 1 below, and the effluent water quality after adding different carbon sources is shown in Table 1 below.

[0074] [Table 1]

[0075]

[0076] As can be seen from Table 1 above, the mixed carbon source conceived according to the present invention can achieve and surpass the effluent treatment effect of conventional carbon sources used in water treatment plants, but with lower carbon source preparation costs. Specifically, the solid carbon source, activated sludge, and spent catalyst do not incur raw material procurement costs for the carbon source, while also achieving waste resource utilization, resulting in significant economic benefits. Furthermore, a comparison of Examples 1 and 3 reveals that the mixed carbon source containing spent catalyst exhibits superior effluent treatment effect compared to the mixed carbon source containing unused catalyst.

[0077] Through summarization and review, this invention develops a mixed carbon source and its preparation method. The mixed carbon source comprises a combination of solid carbon source, liquid carbon source, activated sludge, and catalyst, enabling it to rapidly and continuously provide carbon to wastewater treatment systems. Furthermore, the method for preparing the mixed carbon source in this invention improves upon the problems of high production costs and complex preparation processes in existing technologies, and can be widely applied to municipal wastewater treatment plants and industrial wastewater treatment plants such as those for dyeing and printing.

[0078] Example embodiments have been disclosed herein, and although specific terminology has been used, it is used and interpreted in a general and descriptive sense only, and not for limiting purposes. In some instances, it will be apparent to those skilled in the art up to the time of filing of this application that features, characteristics, and / or elements described in connection with specific embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments, unless expressly stated otherwise. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the claims.

Claims

1. A mixed carbon source, characterized in that, The mixed carbon source includes: Solid carbon source; Liquid carbon sources include at least one of alcohols, organic acids, and sugars; Activated sludge; Catalysts include salts or oxides of transition metals as active components; The catalyst is a waste catalyst from a wastewater or waste gas treatment system; the transition metal includes at least one of Fe, Cu, Mn, Mo, Ni, Zn, Co, and W; the weight ratio of the active component in the catalyst is in the range of 0.02% to 1.2% based on the total weight of the mixed carbon source.

2. The mixed carbon source according to claim 1, characterized in that, Solid carbon sources include at least one of agricultural products and agricultural waste.

3. The mixed carbon source according to claim 2, characterized in that, Agricultural products include tuber-based agricultural products, and agricultural waste includes at least one of the following: crop straw, core, husk, and residue.

4. The mixed carbon source according to claim 3, characterized in that, Agricultural products include at least one of cassava, potatoes, and sweet potatoes, while agricultural waste includes at least one of corn cobs, corn stalks, wheat stalks, peanut shells, soybean stalks, cotton stalks, and sugarcane bagasse.

5. The mixed carbon source according to claim 1, characterized in that, The solid carbon source is in powder form, with a particle size of 100 to 500 mesh.

6. The mixed carbon source according to claim 1, characterized in that, Based on the total weight of the mixed carbon sources, the weight ratio of solid carbon sources ranges from 10% to 30%.

7. The mixed carbon source according to claim 1, characterized in that, Liquid carbon sources include at least one of methanol, ethanol, ethylene glycol, sodium acetate, sodium propionate, glucose, sucrose, and soluble starch.

8. The mixed carbon source according to claim 7, characterized in that, Ethylene glycol is a waste refrigerant recovered from wind turbines.

9. The mixed carbon source according to claim 1, characterized in that, Based on the total weight of the mixed carbon sources, the weight ratio of liquid carbon sources ranges from 40% to 79%.

10. The mixed carbon source according to claim 1, characterized in that, The activated sludge comes from the sedimentation zone of the wastewater treatment facility and has a moisture content in the range of 50% to 90%.

11. The mixed carbon source according to claim 1, characterized in that, Based on the total weight of the mixed carbon sources, the weight ratio of activated sludge is in the range of 10% to 20%.

12. The mixed carbon source according to claim 1, characterized in that, Based on the total weight of the mixed carbon sources, the catalyst also includes a support material in the range of 0.98% to 8.8% by weight. The carrier material includes at least one of magnesium oxide, aluminum oxide, and calcium oxide.

13. A method for preparing a mixed carbon source, used to prepare the mixed carbon source as described in any one of claims 1-12, characterized in that, The method includes: Step 1: Mix the solid carbon source, liquid carbon source and activated sludge evenly, and add them to the ball rolling machine; Step 2: The catalyst is added to a ball-rolling machine for rolling to obtain an initial mixed carbon source; and Step 3: Place the initial mixed carbon source in a dark place for a predetermined period of time to obtain the mixed carbon source.

14. The method according to claim 13, characterized in that, in, Step 1 includes: thoroughly mixing the solid carbon source and activated sludge until homogeneous; and diluting the liquid carbon source and spraying it onto the surface of the mixture of solid carbon source and activated sludge, then mixing thoroughly. In step 2, the components in the ball rolling machine are rolled into granules. Step 3 involves placing the initial mixed carbon source in a cool place for 1 to 3 days to obtain the mixed carbon source.

15. The method according to claim 14, characterized in that, Step 3 also includes spraying liquid onto the surface of the initial mixed carbon source at predetermined time intervals to keep the initial mixed carbon source moist.

16. The method according to claim 13, characterized in that, Based on the total weight of the mixed carbon sources, the weight ratio of solid carbon sources is in the range of 10% to 30%, the weight ratio of liquid carbon sources is in the range of 40% to 79%, the weight ratio of activated sludge is in the range of 10% to 20%, and the weight ratio of active ingredients included in the catalyst is in the range of 0.02% to 1.2%.

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