Denitrification nitrogen removal complex microbial inoculant for industrial wastewater treatment and preparation method of denitrification nitrogen removal complex microbial inoculant
By improving the culture method and carrier selection of bacterial strains, denitrification and nitrogen-decreasing composite bacteria agents were prepared, and magnesium-modified sewage peat and zero-valent iron-loaded sewage peat were used to solve the problem of low nitrogen pollution treatment efficiency in industrial wastewater, and achieve efficient and environmentally friendly wastewater treatment effect.
Patent Information
- Application Number
- CN202510304903.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-06-03
- Estimated Expiration
- Not applicable · inactive patent
AI Technical Summary
When dealing with nitrogen pollution in industrial wastewater in the prior art, physical and chemical methods have problems such as low efficiency and toxicity of by-products. Although biological methods are friendly, their application effect is not ideal.
By improving the culture method and carrier selection of bacterial strains, a denitrification and denitrification composite bacterial agent is prepared, and magnesium-modified sludge-loaded denitrification and denitrification bacterial strains and zero-valent iron-loaded sewage sludge are used to improve the denitrification and denitrification efficiency of wastewater treatment.
It realizes efficient removal of nitrogen in industrial wastewater, avoids the generation of by-products, improves the sewage treatment effect, and is process-friendly and has low cost.
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of wastewater treatment, and specifically to a denitrifying and nitrogen-removing composite bactericide for industrial wastewater treatment and a preparation method thereof. Background Technique
[0002] With the rapid development of the economy, the social life of human beings has been continuously increasing, and the problem of water body pollution has become increasingly serious, becoming a global environmental problem. The nitrogen in water bodies mainly comes from agricultural runoff, industrial wastewater, domestic sewage, etc. Therefore, in order to solve the problem of water body nitrogen pollution, the existing technologies generally use physical methods, chemical methods, and biological methods for wastewater treatment. Physical methods mainly remove nitrogen through adsorption, precipitation, etc.; chemical methods mainly carry out nitrogen conversion through chemical reactions such as oxidation-reduction, but are very likely to produce toxic by-products; biological methods use the metabolic functions of microorganisms for conversion, which are environmentally friendly and low-cost, and are widely used in actual applications.
[0003] This solution provides a denitrifying and nitrogen-removing composite bactericide for industrial wastewater treatment and a preparation method thereof. By improving the strain cultivation method and adjusting the carrier selection, the denitrifying and nitrogen-removing efficiency of the bactericide is improved. Summary of the Invention
[0004] The purpose of the present invention is to provide a denitrifying and nitrogen-removing composite bactericide for industrial wastewater treatment and a preparation method thereof, so as to solve the problems raised in the above background technique.
[0005] In order to solve the above technical problems, the present invention provides the following technical solution: A preparation method of a denitrifying and nitrogen-removing composite bactericide for industrial wastewater treatment, including the following steps: Step 1: Mix dehydrated sludge powder and potassium hydroxide solution, stir for 10 - 12 h, dry at 100 - 110 °C for 10 - 12 h, grind and crush, then mix the crushed sludge powder and magnesium chloride solution, stir for 4 - 8 h, dry at 100 - 110 °C for 8 - 10 h, then transfer to a tubular furnace, heat up to 450 - 500 °C under a nitrogen atmosphere, pyrolyze for 2 - 3 h, cool to room temperature, wash with deionized water until neutral, and dry at 80 - 90 °C to obtain modified sludge carbon; Step 2: Mix the modified sludge carbon and ferrous sulfate heptahydrate, stir for 30 - 40 min, then add tea polyphenols, continue to stir for 10 - 20 min, react in a water bath at 50 - 60 °C for 3 - 4 days, take out and wash with deionized water, and vacuum dry at 45 - 55 °C to obtain zero-valent iron-loaded sludge carbon; Step 3: Inoculate Paracoccus and Ochrobactrum into the culture medium respectively for culture and domestication. Zero-valent iron-loaded sludge carbon is added to the culture medium. During the culture and domestication, the temperature is slowly decreased from 10°C to 4 - 6°C to obtain domesticated Paracoccus and domesticated Ochrobactrum. The domesticated Paracoccus and domesticated Ochrobactrum are respectively added to the culture medium for culture. The two kinds of bacterial solutions are collected and mixed to obtain a compound bacterial solution. Then, modified sludge carbon is added, and the mixture is oscillated at 30°C for 20 - 24 h. After taking out, it is filtered and freeze-dried to obtain a composite bacterial agent.
[0006] In a more optimized scheme, in Step 1, the solid-liquid ratio of dehydrated sludge powder to potassium hydroxide solution is 1:(20 - 25); the concentration of the potassium hydroxide solution is 1 - 1.2 mol / L; the solid-liquid ratio of the crushed sludge powder to magnesium chloride solution is 1:(10 - 12); the concentration of the magnesium chloride solution is 0.3 - 0.5 mol / L; the heating rate during pyrolysis is 8 - 10°C / min.
[0007] In a more optimized scheme, in Step 2, the mass ratio of the modified sludge carbon, ferrous sulfate heptahydrate, and tea polyphenols is 2:4:(6.2 - 6.5).
[0008] In a more optimized scheme, in Step 3, in the compound bacterial solution, the volume ratio of the domesticated Paracoccus bacterial solution to the domesticated Ochrobactrum bacterial solution is (1 - 2):1; the dosage of the modified sludge carbon and the compound bacterial solution is 2 g:(100 - 200) mL.
[0009] In a more optimized scheme, the dosage of each component of the culture medium is: beef extract 3 - 5 g / L, peptone 10 - 12 g / L, sodium chloride 5 - 6 g / L, agar 20 - 25 g / L, and the pH is adjusted to 7 with 1 mol / L sodium hydroxide.
[0010] In a more optimized scheme, during the culture and domestication, the addition amount of zero-valent iron-loaded sludge carbon in the culture medium is 0.5 - 1 g / L.
[0011] In a more optimized scheme, during the culture and domestication, the cooling rate is 0.5 - 1°C / min.
[0012] In a more optimized scheme, a denitrifying and nitrogen-removing composite bacterial agent for industrial wastewater treatment prepared by the preparation method according to any one of the above.
[0013] In a more optimized scheme, an application of a denitrifying and nitrogen-removing composite bacterial agent for industrial wastewater treatment. During the application, industrial wastewater, the composite bacterial agent, and zero-valent iron-loaded sludge carbon are mixed, oscillated and stirred for wastewater treatment.
[0014] Compared with the prior art, the beneficial effects achieved by the present invention are: The present invention discloses a denitrifying and nitrogen-removing composite bacterial agent for industrial wastewater treatment and a preparation method thereof. The scheme is as follows: after dehydrated sludge powder is activated by potassium hydroxide solution, magnesium chloride solution is added, and magnesium-modified sludge carbon is prepared by pyrolysis. Then, using tea polyphenol as a reducing agent, zero-valent iron is loaded on the surface of magnesium-modified sludge carbon to obtain zero-valent iron-loaded sludge carbon. On this basis, the scheme uses magnesium-modified sludge carbon to load denitrifying and nitrogen-removing bacterial strains, and the selected bacterial strains are Paracoccus and Ochrobactrum. They are compounded with zero-valent iron-loaded sludge carbon and applied to industrial wastewater to improve the denitrifying and nitrogen-removing efficiency, and the actual sewage treatment effect is excellent.
[0015] In this scheme, the present application uses tea polyphenol as a reducing agent to generate zero-valent iron. On the one hand, by using the coating effect of tea polyphenol and cooperating with the loading of magnesium-modified sludge carbon, the dispersibility and slow-release performance of zero-valent iron are improved. On the other hand, to avoid the excessive coating of tea polyphenol affecting the nitrogen-removing effect of the bacterial strains, the technical parameter is limited to "the mass ratio of the modified sludge carbon, ferrous sulfate heptahydrate, and tea polyphenol is 2:4:(6.2 - 6.5)". Under this parameter, the nitrogen-removing effect is the most excellent.
[0016] At the same time, the scheme uses zero-valent iron-loaded sludge carbon as the domestication parameter, adds it to the culture medium for bacterial strain domestication, and the temperature is slowly lowered from 10°C to 4 - 6°C during domestication to obtain low-temperature-tolerant bacterial strains that can adapt to zero-valent iron-loaded sludge carbon, avoiding the influence of the nitrogen-removing effect caused by some bacterial strains being unable to adapt to the presence of zero-valent iron when compounded with zero-valent iron-loaded sludge carbon in the future.
[0017] The present invention discloses a denitrifying and nitrogen-removing composite bacterial agent for industrial wastewater treatment and a preparation method thereof. The scheme domesticates Paracoccus and Ochrobactrum and loads them on the surface of magnesium-modified activated carbon, and then compoundly uses them with zero-valent iron-loaded sludge carbon to achieve denitrifying and nitrogen-removing of industrial wastewater, with high practicability. Specific Embodiments
[0018] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.
[0019] In the following embodiments, the dehydrated sludge powder is dried and then ball-milled, and after passing through a 100-mesh sieve, the embodiment preparation is carried out; Paracoccus is purchased from Beina Culture Collection Center, and the strain number is BNCC336866; Ochrobactrum is purchased from China General Microbiological Culture Collection Center, and the number is CGMCC No.8839.
[0020] Example 1: A preparation method of a denitrifying and nitrogen-removing composite bacterial agent for industrial wastewater treatment, including the following steps: Step 1: Mix dehydrated sludge powder and potassium hydroxide solution, stir for 10 h, dry at 100 °C for 12 h, grind and crush. Then mix the crushed sludge powder and magnesium chloride solution, stir for 4 h, dry at 100 °C for 10 h. Then transfer it to a tubular furnace, heat up to 450 °C under a nitrogen atmosphere, pyrolyze for 3 h. After cooling to room temperature, wash with deionized water until neutral, and dry at 80 °C to obtain modified sludge carbon.
[0021] In Step 1, the solid-liquid ratio of the dehydrated sludge powder to the potassium hydroxide solution is 1:25; the concentration of the potassium hydroxide solution is 1.2 mol / L; the solid-liquid ratio of the crushed sludge powder to the magnesium chloride solution is 1:12; the concentration of the magnesium chloride solution is 0.4 mol / L; the heating rate during pyrolysis is 8 °C / min.
[0022] Step 2: Mix the modified sludge carbon and ferrous sulfate heptahydrate, stir for 30 min, then add tea polyphenols, continue to stir for 20 min, react in a water bath at 50 °C for 4 days. After taking out, wash with deionized water and vacuum dry at 45 °C to obtain zero-valent iron-loaded sludge carbon.
[0023] In Step 2, the mass ratio of the modified sludge carbon, ferrous sulfate heptahydrate, and tea polyphenols is 2:4:6.2.
[0024] Step 3: Inoculate Paracoccus and Ochrobactrum into the culture medium respectively for cultivation and domestication. Add zero-valent iron-loaded sludge carbon to the culture medium. During cultivation and domestication, the temperature is slowly decreased from 10 °C to 6 °C to obtain domesticated Paracoccus and domesticated Ochrobactrum. Add the domesticated Paracoccus and domesticated Ochrobactrum to the culture medium for cultivation respectively, collect the two kinds of bacterial solutions and mix them to obtain a compound bacterial solution. Then add modified sludge carbon, oscillate at 30 °C for 20 h, take out and filter, and freeze-dry to obtain a composite bacterial agent.
[0025] In Step 3, in the compound bacterial solution, the volume ratio of the domesticated Paracoccus bacterial solution to the domesticated Ochrobactrum bacterial solution is 1.5:1; the dosage of the modified sludge carbon and the compound bacterial solution is 2 g:200 mL. The dosage of each component of the culture medium is: beef extract 5 g / L, peptone 12 g / L, sodium chloride 5 g / L, agar 24 g / L, and the pH is adjusted to 7 with 1 mol / L sodium hydroxide. During cultivation and domestication, the addition amount of zero-valent iron-loaded sludge carbon in the culture medium is 0.8 g / L. The cooling rate is 0.5 °C / min.
[0026] Example 2: A preparation method of a denitrifying and nitrogen-removing composite bacterial agent for industrial wastewater treatment, comprising the following steps: Step 1: Mix dehydrated sludge powder and potassium hydroxide solution, stir for 11 h, dry at 105 °C for 11 h, grind and crush. Then mix the crushed sludge powder and magnesium chloride solution, stir for 6 h, dry at 105 °C for 9 h. Then transfer it to a tubular furnace, heat up to 480 °C under a nitrogen atmosphere, pyrolyze for 2.5 h. After cooling to room temperature, wash with deionized water until neutral, and dry at 85 °C to obtain modified sludge carbon.
[0027] In Step 1, the solid-liquid ratio of the dehydrated sludge powder to the potassium hydroxide solution is 1:25; the concentration of the potassium hydroxide solution is 1.2 mol / L; the solid-liquid ratio of the crushed sludge powder to the magnesium chloride solution is 1:12; the concentration of the magnesium chloride solution is 0.4 mol / L; the heating rate during pyrolysis is 8 °C / min.
[0028] Step 2: Mix the modified sludge carbon and ferrous sulfate heptahydrate, stir for 35 min, then add tea polyphenols and continue to stir for 15 min. React in a water bath at 55 °C for 3 days. After taking out, wash with deionized water and dry under vacuum at 50 °C to obtain zero-valent iron-loaded sludge carbon.
[0029] In Step 2, the mass ratio of the modified sludge carbon, ferrous sulfate heptahydrate, and tea polyphenols is 2:4:6.4.
[0030] Step 3: Inoculate Paracoccus and Ochrobactrum into the culture medium respectively for culture and domestication. Add zero-valent iron-loaded sludge carbon to the culture medium. During culture and domestication, the temperature slowly drops from 10 °C to 6 °C to obtain domesticated Paracoccus and domesticated Ochrobactrum. Add the domesticated Paracoccus and domesticated Ochrobactrum to the culture medium for culture respectively, collect the two kinds of bacterial solutions and mix them to obtain a compound bacterial solution. Then add modified sludge carbon, oscillate at 30 °C for 22 h, take out and filter, and dry under cold conditions to obtain a composite bacterial agent.
[0031] In Step 3, in the compound bacterial solution, the volume ratio of the domesticated Paracoccus bacterial solution to the domesticated Ochrobactrum bacterial solution is 1.5:1; the dosages of the modified sludge carbon and the compound bacterial solution are 2 g:200 mL. The dosages of each component of the culture medium are: beef extract 5 g / L, peptone 12 g / L, sodium chloride 5 g / L, agar 24 g / L, and adjust the pH to 7 with 1 mol / L sodium hydroxide. During culture and domestication, the addition amount of zero-valent iron-loaded sludge carbon in the culture medium is 0.8 g / L. The cooling rate is 0.5 °C / min.
[0032] Example 3: A preparation method of a denitrifying and nitrogen-removing composite bacterial agent for industrial wastewater treatment, comprising the following steps: Step 1: Mix dehydrated sludge powder and potassium hydroxide solution, stir for 12 h, dry at 110 °C for 10 h, grind and crush. Then mix the crushed sludge powder and magnesium chloride solution, stir for 8 h, dry at 110 °C for 8 h. Then transfer it to a tubular furnace, heat up to 500 °C under a nitrogen atmosphere, pyrolyze for 2 h. After cooling to room temperature, wash with deionized water until neutral, and dry at 90 °C to obtain modified sludge carbon.
[0033] In Step 1, the solid-liquid ratio of the dehydrated sludge powder to the potassium hydroxide solution is 1:25; the concentration of the potassium hydroxide solution is 1.2 mol / L; the solid-liquid ratio of the crushed sludge powder to the magnesium chloride solution is 1:12; the concentration of the magnesium chloride solution is 0.4 mol / L; the heating rate during pyrolysis is 8 °C / min.
[0034] Step 2: Mix the modified sludge carbon and ferrous sulfate heptahydrate, stir for 40 min, then add tea polyphenols, continue to stir for 20 min, react in a 60 °C water bath for 3 days. After taking out, wash with deionized water and vacuum dry at 55 °C to obtain zero-valent iron-loaded sludge carbon.
[0035] In Step 2, the mass ratio of the modified sludge carbon, ferrous sulfate heptahydrate, and tea polyphenols is 2:4:6.5.
[0036] Step 3: Inoculate Paracoccus and Ochrobactrum into the culture medium respectively for cultivation and domestication. Add zero-valent iron-loaded sludge carbon to the culture medium. During cultivation and domestication, the temperature slowly drops from 10 °C to 6 °C to obtain domesticated Paracoccus and domesticated Ochrobactrum. Add the domesticated Paracoccus and domesticated Ochrobactrum to the culture medium for cultivation respectively, collect the two kinds of bacterial solutions and mix them to obtain a compound bacterial solution. Then add modified sludge carbon, oscillate at 30 °C for 24 h, take out and filter, and freeze-dry to obtain a composite bactericide.
[0037] In Step 3, in the compound bacterial solution, the volume ratio of the domesticated Paracoccus bacterial solution to the domesticated Ochrobactrum bacterial solution is 1.5:1; the dosage of the modified sludge carbon and the compound bacterial solution is 2 g:200 mL. The dosage of each component of the culture medium is: beef extract 5 g / L, peptone 12 g / L, sodium chloride 5 g / L, agar 24 g / L, and the pH is adjusted to 7 with 1 mol / L sodium hydroxide. During cultivation and domestication, the addition amount of zero-valent iron-loaded sludge carbon in the culture medium is 0.8 g / L. The cooling rate is 0.5 °C / min.
[0038] Example 4: A preparation method of a denitrifying and nitrogen-removing composite bactericide for industrial wastewater treatment, comprising the following steps: Step 1: Mix dehydrated sludge powder and potassium hydroxide solution, stir for 12 h, dry at 110 °C for 10 h, grind and crush. Then mix the crushed sludge powder and magnesium chloride solution, stir for 8 h, dry at 110 °C for 8 h. Then transfer it to a tubular furnace, heat up to 500 °C under a nitrogen atmosphere, pyrolyze for 2 h. After cooling to room temperature, wash with deionized water until neutral, and dry at 90 °C to obtain modified sludge carbon.
[0039] In Step 1, the solid-liquid ratio of the dehydrated sludge powder and the potassium hydroxide solution is 1:25; the concentration of the potassium hydroxide solution is 1.2 mol / L; the solid-liquid ratio of the crushed sludge powder and the magnesium chloride solution is 1:12; the concentration of the magnesium chloride solution is 0.4 mol / L; the heating rate during pyrolysis is 8 °C / min.
[0040] Step 2: Mix the modified sludge carbon and ferrous sulfate heptahydrate, stir for 40 min, then add tea polyphenols, continue to stir for 20 min, react in a 60 °C water bath for 3 days. After taking it out, wash with deionized water and dry under vacuum at 55 °C to obtain zero-valent iron-loaded sludge carbon.
[0041] In Step 2, the mass ratio of the modified sludge carbon, ferrous sulfate heptahydrate, and tea polyphenols is 2:4:6.5.
[0042] Step 3: Inoculate Paracoccus and Ochrobactrum into the culture medium respectively for cultivation and domestication. Add zero-valent iron-loaded sludge carbon to the culture medium. During cultivation and domestication, the temperature is slowly decreased from 10 °C to 6 °C to obtain domesticated Paracoccus and domesticated Ochrobactrum. Add the domesticated Paracoccus and domesticated Ochrobactrum to the culture medium for cultivation respectively, collect the two kinds of bacterial solutions and mix them to obtain a compound bacterial solution. Then add modified sludge carbon, oscillate at 30 °C for 24 h. After taking it out, filter and freeze-dry to obtain a composite bacterial agent.
[0043] In Step 3, in the compound bacterial solution, the volume ratio of the domesticated Paracoccus bacterial solution to the domesticated Ochrobactrum bacterial solution is 1.5:1; the dosage of the modified sludge carbon and the compound bacterial solution is 2 g:200 mL. The dosage of each component of the culture medium is: beef extract 5 g / L, peptone 12 g / L, sodium chloride 5 g / L, agar 24 g / L, and the pH is adjusted to 7 with 1 mol / L sodium hydroxide. During cultivation and domestication, the addition amount of zero-valent iron-loaded sludge carbon in the culture medium is 0.5 g / L. The cooling rate is 0.5 °C / min.
[0044] Comparative Example 1: A preparation method of a denitrifying and nitrogen-removing composite bacterial agent for industrial wastewater treatment, comprising the following steps: Step 1: Mix dehydrated sludge powder and potassium hydroxide solution, stir for 12 h, dry at 110 °C for 10 h, grind and crush. Then mix the crushed sludge powder and magnesium chloride solution, stir for 8 h, dry at 110 °C for 8 h. Then transfer it to a tubular furnace, heat up to 500 °C under a nitrogen atmosphere, pyrolyze for 2 h. After cooling to room temperature, wash with deionized water until neutral, and dry at 90 °C to obtain modified sludge carbon.
[0045] In Step 1, the solid-liquid ratio of the dehydrated sludge powder to the potassium hydroxide solution is 1:25; the concentration of the potassium hydroxide solution is 1.2 mol / L; the solid-liquid ratio of the crushed sludge powder to the magnesium chloride solution is 1:12; the concentration of the magnesium chloride solution is 0.4 mol / L; the heating rate during pyrolysis is 8 °C / min.
[0046] Step 2: Mix the modified sludge carbon and ferrous sulfate heptahydrate, stir for 40 min, then add tea polyphenols, continue to stir for 20 min, react in a 60 °C water bath for 3 days. After taking out, wash with deionized water and dry under vacuum at 55 °C to obtain zero-valent iron-loaded sludge carbon.
[0047] In Step 2, the mass ratio of the modified sludge carbon, ferrous sulfate heptahydrate, and tea polyphenols is 2:4:7.5.
[0048] Step 3: Inoculate Paracoccus and Ochrobactrum into the medium respectively for cultivation and domestication. Add zero-valent iron-loaded sludge carbon to the medium. During cultivation and domestication, the temperature is slowly decreased from 10 °C to 6 °C to obtain domesticated Paracoccus and domesticated Ochrobactrum. Add the domesticated Paracoccus and domesticated Ochrobactrum to the medium for cultivation respectively, collect the two kinds of bacterial solutions and mix them to obtain a compound bacterial solution. Then add modified sludge carbon, oscillate at 30 °C for 24 h, take out and filter, and freeze-dry to obtain a composite bactericide.
[0049] In Step 3, in the compound bacterial solution, the volume ratio of the domesticated Paracoccus bacterial solution to the domesticated Ochrobactrum bacterial solution is 1.5:1; the dosage of the modified sludge carbon and the compound bacterial solution is 2 g:200 mL. The dosage of each component of the medium is: beef extract 5 g / L, peptone 12 g / L, sodium chloride 5 g / L, agar 24 g / L, and the pH is adjusted to 7 with 1 mol / L sodium hydroxide. During cultivation and domestication, the addition amount of zero-valent iron-loaded sludge carbon in the medium is 0.8 g / L. The cooling rate is 0.5 °C / min.
[0050] Comparative Example 2: A preparation method of a denitrifying and nitrogen-removing composite bactericide for industrial wastewater treatment, comprising the following steps: Step 1: Mix dehydrated sludge powder and potassium hydroxide solution, stir for 12 h, dry at 110 °C for 10 h, grind and crush. Then mix the crushed sludge powder and magnesium chloride solution, stir for 8 h, dry at 110 °C for 8 h. Then transfer it to a tubular furnace, heat up to 500 °C under a nitrogen atmosphere, pyrolyze for 2 h. After cooling to room temperature, wash with deionized water until neutral, and dry at 90 °C to obtain modified sludge carbon.
[0051] In Step 1, the solid-liquid ratio of the dehydrated sludge powder to the potassium hydroxide solution is 1:25; the concentration of the potassium hydroxide solution is 1.2 mol / L; the solid-liquid ratio of the crushed sludge powder to the magnesium chloride solution is 1:12; the concentration of the magnesium chloride solution is 0.4 mol / L; the heating rate during pyrolysis is 8 °C / min.
[0052] Step 2: Mix the modified sludge carbon and ferrous sulfate heptahydrate, stir for 40 min, then add tea polyphenols, continue to stir for 20 min, react in a 60 °C water bath for 3 days. After taking out, wash with deionized water and vacuum dry at 55 °C to obtain zero-valent iron-loaded sludge carbon.
[0053] In Step 2, the mass ratio of the modified sludge carbon, ferrous sulfate heptahydrate, and tea polyphenols is 2:4:6.5.
[0054] Step 3: Inoculate Paracoccus and Ochrobactrum into the medium respectively for cultivation and domestication. Add zero-valent iron-loaded sludge carbon to the medium. During cultivation and domestication, the temperature is slowly decreased from 10 °C to 6 °C to obtain domesticated Paracoccus and domesticated Ochrobactrum. Add the domesticated Paracoccus and domesticated Ochrobactrum to the medium for cultivation respectively, collect the two kinds of bacterial solutions and mix them to obtain a compound bacterial solution. Then add modified sludge carbon, oscillate at 30 °C for 24 h, take out and filter, and freeze-dry to obtain a composite bactericide.
[0055] In Step 3, in the compound bacterial solution, the volume ratio of the domesticated Paracoccus bacterial solution to the domesticated Ochrobactrum bacterial solution is 1.5:1; the dosages of the modified sludge carbon and the compound bacterial solution are 2 g:200 mL. The dosages of each component of the medium are: beef extract 5 g / L, peptone 12 g / L, sodium chloride 5 g / L, agar 24 g / L, and the pH is adjusted to 7 with 1 mol / L sodium hydroxide. During cultivation and domestication, the addition amount of zero-valent iron-loaded sludge carbon in the medium is 0.3 g / L. The cooling rate is 0.5 °C / min.
[0056] Comparative Example 3: A preparation method of a denitrifying and nitrogen-removing composite bactericide for industrial wastewater treatment, comprising the following steps: Step 1: Mix the dehydrated sludge powder and potassium hydroxide solution, stir for 12 h, dry at 110 °C for 10 h, grind and crush. Then mix the crushed sludge powder and magnesium chloride solution, stir for 8 h, dry at 110 °C for 8 h. Then transfer it to a tubular furnace, heat up to 500 °C under a nitrogen atmosphere, pyrolyze for 2 h. After cooling to room temperature, wash with deionized water until neutral, and dry at 90 °C to obtain modified sludge carbon.
[0057] In Step 1, the solid-liquid ratio of the dehydrated sludge powder and potassium hydroxide solution is 1:25; the concentration of the potassium hydroxide solution is 1.2 mol / L; the solid-liquid ratio of the crushed sludge powder and magnesium chloride solution is 1:12; the concentration of the magnesium chloride solution is 0.4 mol / L; the heating rate during pyrolysis is 8 °C / min.
[0058] Step 2: Mix the modified sludge carbon and ferrous sulfate heptahydrate, stir for 40 min, then add tea polyphenols, continue to stir for 20 min. React in a water bath at 60 °C for 3 days. After taking out, wash with deionized water and dry under vacuum at 55 °C to obtain zero-valent iron-loaded sludge carbon.
[0059] In Step 2, the mass ratio of the modified sludge carbon, ferrous sulfate heptahydrate, and tea polyphenols is 2:4:6.5.
[0060] Step 3: Inoculate Paracoccus and Ochrobactrum anthropi into the culture medium respectively and carry out cultivation and domestication. During cultivation and domestication, the temperature is slowly decreased from 10 °C to 6 °C to obtain domesticated Paracoccus and domesticated Ochrobactrum anthropi. Add the domesticated Paracoccus and domesticated Ochrobactrum anthropi into the culture medium for cultivation respectively, collect the two kinds of bacterial solutions and mix them to obtain a compound bacterial solution. Then add the modified sludge carbon, oscillate at 30 °C for 24 h. After taking out, filter and freeze-dry to obtain a composite bactericide.
[0061] In Step 3, in the compound bacterial solution, the volume ratio of the domesticated Paracoccus bacterial solution to the domesticated Ochrobactrum anthropi bacterial solution is 1.5:1; the dosages of the modified sludge carbon and the compound bacterial solution are 2 g:200 mL. The dosages of each component of the culture medium are: beef extract 5 g / L, peptone 12 g / L, sodium chloride 5 g / L, agar 24 g / L, and the pH is adjusted to 7 with 1 mol / L sodium hydroxide. During cultivation and domestication, the addition amount of zero-valent iron-loaded sludge carbon in the culture medium is 0 g / L. The cooling rate is 0.5 °C / min.
[0062] Detection experiment: 1. Prepare the composite bacterial agent according to the methods disclosed in Examples 1-4 and Comparative Examples 1-3. Add the composite bacterial agent and zero-valent iron-loaded sludge carbon to 200 mL of sewage. The concentration of zero-valent iron-loaded sludge carbon is 0.5 g / L, and the addition amount of the composite bacterial agent is 5 wt%. The initial COD of the sewage is 250 mg / L, the initial ammonia nitrogen concentration is 50 mg / L, the test temperature is 6 °C, oscillate for 72 h, detect and calculate the ammonia nitrogen removal rate at 72 h, and perform a detection every 24 h of oscillation to calculate the ammonia nitrogen removal rate at 24 h. The specific data are shown in Table 1.
[0063] Table 1 Project Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Ammonia nitrogen removal rate in 24 h 35.6% 36.2% 36.9% 32.7% 31.4% 30.3% 28.7% Ammonia nitrogen removal rate in 72 h 69.4% 71.3% 72.8% 65.2% 67.1% 62.4% 58.7% Conclusion: The present invention discloses a denitrifying and nitrogen-removing composite bacterial agent for industrial wastewater treatment and its preparation method. The scheme activates dehydrated sludge powder with potassium hydroxide solution, adds magnesium chloride solution, and pyrolyzes to prepare magnesium-modified sludge carbon. Then, using tea polyphenol as a reducing agent, zero-valent iron is loaded on the surface of magnesium-modified sludge carbon to obtain zero-valent iron-loaded sludge carbon. On this basis, the scheme uses magnesium-modified sludge carbon to load denitrifying and nitrogen-removing bacterial strains, and the bacterial strains are selected as a mixture of Paracoccus and Ochrobactrum. It is compounded with zero-valent iron-loaded sludge carbon and applied to industrial wastewater to improve the denitrifying and nitrogen-removing efficiency, and the actual sewage treatment effect is excellent.
[0064] For those skilled in the art, it is obvious that the present invention is not limited to the details of the above exemplary embodiments, and can be implemented in other specific forms without departing from the spirit or basic characteristics of the present invention. Therefore, from any point of view, the embodiments should be regarded as exemplary and non-limiting. The scope of the present invention is defined by the appended claims rather than the above description. Therefore, it is intended to include all changes falling within the meaning and scope of the equivalent elements of the claims in the present invention.
Claims
1. A method for preparing a composite denitrification and denitrification bacterial agent for industrial wastewater treatment, characterized in that: The following steps are involved: Step 1: Mix the dehydrated sludge powder and potassium hydroxide solution, stir for 10-12 hours, dry at 100-110°C for 10-12 hours, grind and crush, then mix the crushed sludge powder and magnesium chloride solution, stir for 4-8 hours, dry at 100-110°C for 8-10 hours, transfer to a tube furnace, heat to 450-500°C under a nitrogen atmosphere, pyrolyze for 2-3 hours, cool to room temperature, wash with deionized water until neutral, and dry at 80-90°C to obtain modified sludge charcoal; Step 2: Mix the modified sludge carbon and ferrous sulfate heptahydrate, stir for 30-40 minutes, then add tea polyphenols, continue stirring for 10-20 minutes, react in a water bath at 50-60°C for 3-4 days, take out and wash with deionized water, and vacuum dry at 45-55°C to obtain zero-valent iron-loaded sludge carbon; Step 3: Inoculate Paracoccus and Ochrobacterium into the culture medium respectively for cultivation and domestication, add zero-valent iron-loaded sludge carbon into the culture medium, slowly cool down the temperature from 10°C to 4-6°C during the cultivation and domestication to obtain domesticated Paracoccus and domesticated Ochrobacterium, add the domesticated Paracoccus and domesticated Ochrobacterium into the culture medium respectively for cultivation, collect the two bacterial liquids and mix them to obtain a composite bacterial liquid, then add the modified sludge carbon, oscillate at 30°C for 20-24h, take out and filter, cold dry, and obtain a composite bacterial agent.
2. The method for preparing a composite denitrification and denitrification bacterial agent for industrial wastewater treatment according to claim 1, characterized in that: In step 1, the solid-liquid ratio of the dehydrated sludge powder and the potassium hydroxide solution is 1: (20-25); the concentration of the potassium hydroxide solution is 1-1.2 mol / L; the solid-liquid ratio of the crushed sludge powder and the magnesium chloride solution is 1: (10-12); the concentration of the magnesium chloride solution is 0.3-0.5 mol / L; and the heating rate during pyrolysis is 8-10°C / min.
3. The method for preparing a composite denitrification and denitrification bacterial agent for industrial wastewater treatment according to claim 1, characterized in that: In step 2, the mass ratio of the modified sludge charcoal, ferrous sulfate heptahydrate, and tea polyphenols is 2:4:(6.2-6.5).
4. The method for preparing a composite denitrification and denitrification bacterial agent for industrial wastewater treatment according to claim 1, characterized in that: In step 3, in the composite bacterial solution, the volume ratio of the domesticated Paracoccus bacterial solution and the domesticated Ochrobacter bacterial solution is (1-2):1; the amount of modified sludge charcoal and the composite bacterial solution is 2g: (100-200)mL.
5. The method for preparing a composite denitrification and denitrification bacterial agent for industrial wastewater treatment according to claim 1, characterized in that: The dosage of each component of the culture medium is: beef extract 3~5g / L, peptone 10~12g / L, sodium chloride 5~6g / L, agar 20~25g / L, and the pH is adjusted to 7 with 1mol / L sodium hydroxide.
6. The method for preparing a composite denitrification and denitrification bacterial agent for industrial wastewater treatment according to claim 1, characterized in that: During culture and acclimatization, the amount of zero-valent iron-loaded sludge added to the culture medium was 0.5~1g / L.
7. The method for preparing a composite denitrification and denitrification bacterial agent for industrial wastewater treatment according to claim 1, characterized in that: During culture and acclimatization, the cooling rate is 0.5~1℃ / min.
8. A composite denitrification and denitrification bacterial agent for industrial wastewater treatment prepared according to the preparation method according to any one of claims 1 to 7.
9. The use of a composite denitrification bacterial agent for industrial wastewater treatment according to claim 8, characterized in that: When used, industrial wastewater, composite bacterial agent and zero-valent iron loaded sludge are mixed, shaken and stirred to treat the wastewater.