A composite biological additive for advanced treatment of high-nitrogen sewage

Abstract

The present application relates to sewage treatment technical field, especially a kind of composite biological additive for high-nitrogen sewage advanced treatment.The present application obtains a high-quality fermentation liquor by using specific enzymolysis sequence enzymolysis agricultural derivative, wherein it contains more reducing sugar and organic small molecule acid, and COD equivalent is extremely high, is 2~5 times of the carbon source COD used by conventional sewage plant, and has excellent effect when used as biological carbon source for sewage treatment;Meanwhile, the fermentation liquor is compounded and adjusted with AOB bacterial agent to obtain composite biological additive, the composite biological additive can provide sufficient high-quality nutrient ingredients for denitrifying bacteria, and also inoculate AOB bacteria for sewage treatment system, so that AOB bacteria in the system gradually develop into main nitrosation bacteria group, and have excellent enhanced denitrification effect on high-nitrogen sewage, and have wide application prospect.

Description

Technical Field

[0001] This invention relates to the field of wastewater treatment technology, and in particular to a composite biological additive for the deep treatment of high-nitrogen wastewater. Background Technology

[0002] High-ammonia nitrogen wastewater is one of the most difficult types of industrial wastewater to treat. Traditional wastewater treatment processes for nitrogen removal are inefficient and resource-intensive. How to efficiently and economically treat high-ammonia nitrogen industrial wastewater is a key research project in the field of environmental protection. Summary of the Invention

[0003] To address the aforementioned technical challenges, this invention provides a method for preparing an ultrasonic enzyme-catalyzed fermentation broth of an agricultural derivative, comprising: mixing the agricultural derivative with an alkaline solution and then ultrasonically treating the mixture, followed by enzymatic hydrolysis using cellulase, hemicellulase, pectinase, and laccase in sequence, to obtain the ultrasonic enzyme-catalyzed fermentation broth of the agricultural derivative.

[0004] Preferably, the agricultural derivative is corn stalk.

[0005] Preferably, the alkaline solution is a NaOH solution.

[0006] Preferably, after the agricultural derivative is mixed with the alkaline solution, the mass concentration of the agricultural derivative is 10% to 30%, and the mass concentration of the alkali is 2% to 8%.

[0007] Preferably, the ultrasonic power is 2~10 W / mL.

[0008] Preferably, after ultrasonic treatment, the pH is adjusted to 4.6-5.0, and cellulase is added for enzymatic hydrolysis at 45℃-55℃; then the pH is adjusted to 4.8-5.2, and hemicellulase is added for enzymatic hydrolysis at 45℃-55℃; then the pH is adjusted to 3.8-4.2, and pectinase is added for enzymatic hydrolysis at 45℃-55℃; finally, the pH is adjusted to 2.8-3.2, and laccase is added for enzymatic hydrolysis at 25℃-35℃.

[0009] Preferably, the agricultural derivative ultrasonic enzyme-catalyzed fermentation broth is prepared by filtering after laccase enzymatic hydrolysis and then distilling under reduced pressure at 25℃~35℃.

[0010] Furthermore, the present invention provides an agricultural derivative ultrasonic enzyme-catalyzed fermentation broth, which is prepared by the aforementioned preparation method.

[0011] Furthermore, the present invention provides a composite biological additive containing the aforementioned agricultural derivative ultrasonic enzyme-catalyzed fermentation broth.

[0012] Preferably, the composite biological additive includes: agricultural derivative ultrasonic enzyme-catalyzed fermentation broth, dextran-coated AOB bacterial agent, dissolving and freezing point lowering agent, pH adjuster, promoter, and trace elements.

[0013] Preferably, the AOB inoculant is BioPower103 autotrophic short-range nitrifying bacteria inoculant; the dissolving and freezing point lowering agent is ethylene glycol; the pH adjuster is acetic acid; the promoter is B vitamins and glutamic acid; and the trace element is at least one of iron, zinc, and manganese.

[0014] Preferably, the composite biological additive comprises the following components by weight: 60-90 parts of agricultural derivative ultrasonic enzyme-catalyzed fermentation broth, 20-30 parts of AOB bacterial agent encapsulated with dextran, 3-10 parts of dissolving and freezing point lowering agent, 0.1-1 parts of pH adjuster, 0.1-1 parts of promoter, and 0.1-1 parts of trace elements.

[0015] Preferably, the dextran-coated AOB bacterial agent is prepared by mixing a dextran solution with an AOB bacterial agent under anaerobic conditions and then adding a crosslinking agent for crosslinking.

[0016] Furthermore, the present invention provides the application of the aforementioned composite biological additive in the treatment of high-nitrogen wastewater.

[0017] Preferably, the total nitrogen (TN) of the high-nitrogen wastewater is above 870 mg / L, and the ammonia nitrogen (NH3-N) is above 430 mg / L.

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] This invention yields a high-quality fermentation broth by enzymatically hydrolyzing agricultural derivatives using a specific enzymatic hydrolysis sequence. This broth contains a high amount of reducing sugars and small organic molecules, exhibiting an extremely high COD equivalent, 2-5 times that of conventional carbon sources used in wastewater treatment plants. It demonstrates excellent performance as a biological carbon source for wastewater treatment. Furthermore, this fermentation broth is compounded with AOB (Alternating Oxygen Obstacles) bacteria to obtain a composite biological additive. This additive provides sufficient high-quality nutrients for denitrifying bacteria and inoculates the wastewater treatment system with AOB bacteria, enabling the AOB bacteria within the system to gradually develop into the dominant nitrifying bacteria population. This results in superior enhanced denitrification of high-nitrogen wastewater and has broad application prospects. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this invention, not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention. In the embodiments provided in this specification, unless specific techniques or conditions are specified, they should be performed according to the techniques or conditions described in the literature in this field, or according to the product instructions. Reagents or instruments whose manufacturers are not specified are all conventional products that can be purchased through legitimate channels. The enzymes used in the following embodiments were all purchased from Shandong Longket Enzyme Preparation Co., Ltd. The AOB bacterial agent in the following embodiments is BioPower103 autotrophic short-range nitrifying bacteria agent. The preparation method of dextran-coated AOB bacterial agent in the following examples is as follows: Dextran with a molecular weight of 75-100 kDa is selected, and the dextran is dissolved in deionized water to prepare a 5% solution. The pH of the solution is adjusted to 6.5. Then, under anaerobic conditions, the AOB bacterial agent and the dextran solution are mixed at a mass ratio of 1:20. The mixture is slowly stirred to ensure that the bacteria and solution are evenly distributed. After stirring for 30 minutes, 0.5% glutaraldehyde solution is added to crosslink the bacteria, thus obtaining the dextran-coated AOB bacterial agent.

[0021] Ethylene glycol was used as the melting point and freezing point depressant in the following examples. Acetic acid was used as the pH adjuster in the following examples. A mixture of equal mass ratios of B vitamins and glutamic acid was used as the accelerator in the following examples. A mixture of equal mass ratios of iron, zinc, and manganese was used as the trace element in the following examples.

[0022] Example 1

[0023] This embodiment provides a method for preparing an agricultural derivative ultrasonic enzyme-catalyzed fermentation broth, the steps of which are as follows:

[0024] Corn stalks, crushed to approximately 1 cm in size, were mixed with NaOH solution to prepare a mixture with a corn stalk concentration of 20% and a sodium hydroxide concentration of 3%. After thorough mixing, the mixture was ultrasonically treated (4 W / mL) for 30 min. The pH was then adjusted to 4.8, and cellulase (20 U / g corn stalks) was added, followed by enzymatic hydrolysis at 50℃ for 48 h. Next, the pH was adjusted to 5.0, and hemicellulase (40 U / g corn stalks) was added, followed by enzymatic hydrolysis at 50℃ for 24 h. The pH was then adjusted to 4.0, and pectinase (15 U / g corn stalks) was added, followed by enzymatic hydrolysis at 50℃ for 6 h. Finally, the pH was adjusted to 3.0, and laccase (20 U / g corn stalks) was added, followed by enzymatic hydrolysis at 30℃ for 6 h. The mixture was then filtered and subjected to low-temperature vacuum distillation at 30℃ for 1 h to obtain the corn stalk ultrasonic enzyme-catalyzed fermentation broth.

[0025] Tests revealed that the corn stalk ultrasonic enzyme-catalyzed fermentation broth contained reducing sugars and small organic molecules, with a COD equivalent of 995,000 mg / L.

[0026] Furthermore, this embodiment provides a composite biological additive comprising the following raw materials in parts by weight: 90 parts of corn stalk ultrasonic enzyme-catalyzed fermentation broth prepared by the above method, 30 parts of AOB bacterial agent encapsulated with dextran, 6.5 parts of dissolving and freezing point lowering agent, 0.5 parts of pH adjuster, 0.5 parts of promoter, and 0.5 parts of trace elements.

[0027] Example 2

[0028] This embodiment provides a composite biological additive, which differs from Example 1 only in that it includes the following raw materials in parts by weight: 75 parts of corn straw ultrasonic enzyme catalytic fermentation broth prepared by the method of Example 1, 25 parts of AOB bacterial agent coated with dextran, 7.5 parts of dissolving and freezing point lowering agent, 0.4 parts of pH adjuster, 0.4 parts of promoter, and 0.4 parts of trace elements.

[0029] Example 3

[0030] This embodiment provides a composite biological additive, which differs from Example 1 only in that it includes the following raw materials in parts by weight: 60 parts of corn straw ultrasonic enzyme catalytic fermentation broth prepared by the method of Example 1, 20 parts of AOB bacterial agent coated with dextran, 8.5 parts of dissolving and freezing point lowering agent, 0.6 parts of pH adjuster, 0.6 parts of promoter, and 0.6 parts of trace elements.

[0031] Comparative Example

[0032] This comparative example provides a composite biological additive, which differs from Example 1 only in that the preparation method of the corn straw ultrasonic enzyme-catalyzed fermentation broth is different. Specifically, the enzymatic hydrolysis order is changed as follows: laccase, pectinase, cellulase and hemicellulase are used for enzymatic hydrolysis in sequence.

[0033] Testing revealed that the reducing sugars and small organic molecule acids in the corn stalk ultrasonic enzyme-catalyzed fermentation broth prepared in this comparative example were significantly reduced by about 50% compared to Example 1, with a COD equivalent of only 456,000 mg / L.

[0034] Test case

[0035] In this experiment, the composite biological additives prepared in the above examples and comparative examples were applied to the treatment of high-nitrogen wastewater from the same source. The total nitrogen (TN) in the high-nitrogen wastewater influent was 870 mg / L and the ammonia nitrogen (NH3-N) was 430 mg / L. 4.35 g of the composite biological additive was added to each high-nitrogen wastewater. After 48 h of anoxic denitrification, the total nitrogen and ammonia nitrogen content in the effluent was monitored. The test results are shown in Table 1.

[0036] Table 1

[0037]

[0038] It is evident that the composite biological additive of the present invention has excellent treatment effect on high-nitrogen wastewater, significantly reducing the total nitrogen and ammonia nitrogen content in the wastewater.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for preparing an agricultural derivative ultrasonic enzyme-catalyzed fermentation broth, characterized in that, include: The agricultural derivative was mixed with an alkaline solution and then sonicated. After sonication, the pH was adjusted to 4.6–5.0, and cellulase was added for enzymatic hydrolysis at 45–55°C. Then, the pH was adjusted to 4.8–5.2, and hemicellulase was added for enzymatic hydrolysis at 45–55°C. Next, the pH was adjusted to 3.8–4.2, and pectinase was added for enzymatic hydrolysis at 45–55°C. Finally, the pH was adjusted to 2.8–3.2, and laccase was added for enzymatic hydrolysis at 25–35°C. After laccase hydrolysis, the mixture was filtered, and then distilled under reduced pressure at 25–35°C to obtain the ultrasonic enzyme-catalyzed fermentation broth of the agricultural derivative.

2. The preparation method according to claim 1, characterized in that, The agricultural derivative is corn stalks.

3. The preparation method according to claim 1, characterized in that, The alkaline solution is a NaOH solution.

4. An agricultural derivative ultrasonic enzyme-catalyzed fermentation broth, characterized in that, It is prepared by any one of claims 1 to 3.

5. A compound biological additive, characterized in that, It contains the agricultural derivative ultrasonic enzyme-catalyzed fermentation broth as described in claim 4.

6. The composite biological additive according to claim 5, characterized in that, The composite biological additive includes: agricultural derivative ultrasonic enzyme-catalyzed fermentation broth, dextran-encapsulated AOB bacterial agent, dissolving and freezing point lowering agents, pH adjusters, promoters, and trace elements.

7. The composite biological additive according to claim 6, characterized in that, The AOB inoculant is BioPower103 autotrophic short-range nitrifying bacteria inoculant; the dissolving and freezing point lowering agent is ethylene glycol; the pH adjuster is acetic acid; the promoter is B vitamins and glutamic acid; and the trace element is at least one of iron, zinc, and manganese.

8. The composite biological additive according to claim 6, characterized in that, The composite biological additive comprises the following components by weight: 60-90 parts of agricultural derivative ultrasonic enzyme-catalyzed fermentation broth, 20-30 parts of AOB bacterial agent encapsulated with dextran, 3-10 parts of dissolving and freezing point lowering agent, 0.1-1 parts of pH adjuster, 0.1-1 parts of promoter, and 0.1-1 parts of trace elements.

9. The application of the composite biological additive according to any one of claims 5 to 8 in the treatment of high-nitrogen wastewater.

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