Treatment method of livestock and poultry manure water

Abstract

The invention provides a livestock and poultry manure water treatment method which comprises the following steps: firstly adding a biological coagulant into livestock and poultry manure water, and then adding a modified organic coagulant and an inorganic coagulant. The biological coagulant comprises fermentation liquor of bacillus megatherium and bacillus, the modified organic coagulant is starch modified by 2, 3-glycidyl trimethyl ammonium chloride (GTA), and the inorganic coagulant is any one of polyferric sulfate, polyaluminum chloride, polyaluminum sulfate and polyferric chloride. According to the compound composition, the removal capacity of pollutants is improved, and the removal rates of COD, SS and turbidity can reach 80% or above. In addition, the coagulant is easy to degrade and has no toxic effect on the environment and human health, and the method has important application in pollution treatment and waste resource conversion.

Description

Technical Field

[0001] The present invention relates to the technical field of waste resource utilization, and in particular to a method for treating livestock and poultry manure. Background Art

[0002] With the rapid development of livestock and poultry farming, livestock manure has become a significant source of environmental pollution. Livestock manure primarily consists of feces and liquid manure. Liquid manure production is 5-10 times greater than solid manure, reaching an annual output of 2 billion tons. This high proportion of liquid manure, primarily composed of feces, urine, and water generated during pen cleaning, makes it difficult to treat. Because approximately 60% to 80% of nitrogen, phosphorus, and other elements ingested by livestock and poultry are excreted through excrement, livestock manure exhibits "three highs": high organic matter, high suspended solids, and high ammoniacal nitrogen. These characteristics give livestock manure its "dual nature." Its high organic matter and nutrient content allows it, with proper treatment, to be converted into liquid fertilizer, reducing the need for chemical fertilizers, improving soil structure, enhancing soil fertility, and promoting crop growth. However, in some areas, such as the water-connected areas of southern my country, there is insufficient land for the utilization of livestock manure, requiring treatment and discharge to meet standards to avoid environmental pollution.

[0003] The treatment and resource utilization of livestock and poultry manure present technical and economic challenges. The treatment process requires the use of a variety of technical approaches, such as solid-liquid separation, anaerobic fermentation, and aerobic treatment, and the construction of corresponding facilities and equipment. These processes all involve high investment costs and are prone to the generation of odor, insects, and pathogens during the treatment process, increasing the difficulty of treatment. Therefore, finding timely, stable, and efficient methods for the treatment and utilization of livestock and poultry manure is of great significance for environmental protection and resource reuse. Currently, the treatment of livestock and poultry manure typically involves solid-liquid separation followed by fermentation through biogas plants. In this process, the organic matter and nutrients in the manure are converted into biogas slurry, biogas residue, and biogas, achieving resource recycling. However, biogas operations are unstable at most farms. Furthermore, many farms transfer manure collected from farms to storage tanks for intermediate treatment. During storage, fermentation occurs, reducing the organic matter content and the efficiency of subsequent anaerobic fermentation. Therefore, exploring direct treatment of stored manure and streamlining process steps could effectively improve treatment efficiency and reduce infrastructure and operating costs.

[0004] Among the many methods for treating livestock and poultry manure, coagulation is an effective wastewater treatment method. The coagulation process involves adding a coagulant to the wastewater. This adsorbs and aggregates fine suspended and colloidal particles in the wastewater, forming large flocs that facilitate subsequent treatment. This process not only significantly increases the removal rate of suspended solids and some organic matter, but also reduces the burden on subsequent treatment, improving overall treatment efficiency and effectiveness. Common coagulants include organic coagulants, inorganic coagulants, biological coagulants, and composite coagulants of two or more.

[0005] However, organic coagulants and biological coagulants only rely on organic cations to neutralize the colloidal charge, resulting in poor treatment effects and low COD removal rates. They require large dosages to achieve better results and are costly. The residues of some inorganic coagulants after treatment are still harmful to the environment and are difficult to degrade. They can corrode operating equipment over long periods of time and even endanger human health.

[0006] In recent years, the requirements for coagulation treatment have been continuously increasing. In addition to traditional indicators such as turbidity, color, COD, SS, and ammonia nitrogen, coagulants are also required to be environmentally friendly during production and use. Therefore, it is necessary to develop new coagulant compound combinations to meet sewage treatment needs. Summary of the Invention

[0007] The present invention provides a method for treating livestock and poultry manure, which is used to solve the defects of the prior art that organic coagulants and biological coagulants have high treatment efficiency and low cost, while inorganic coagulants have high pollution, and realize the high-efficiency treatment of livestock and poultry manure with low cost and low addition amount.

[0008] In a first aspect, the present invention provides a method for treating livestock and poultry manure, comprising: first adding a biological coagulant to the livestock and poultry manure, mixing it, then adding a compounded modified organic coagulant and an inorganic coagulant, stirring it, and then allowing it to stand; The biocoagulant contains Bacillus megaterium and Bacillus; The modified organic coagulant is modified starch (ST); The inorganic coagulant is any one of polyferric sulfate (PFS), polyaluminium chloride (PAC), polyaluminium sulfate (PAS) and polyferric chloride (PFC).

[0009] Bacillus megaterium Bacillus magaterium , deposit number is CICC 23076; the Bacillus Bacillus sp., with the deposit number CICC 23870.

[0010] The present invention discovered that the above-mentioned organic-inorganic-biological coagulant treatment can form larger, more stable flocs with faster settling rates. This is because the chemical coagulant quickly builds a dense floc skeleton, while the biological coagulant fills the floc pores through the adhesion of extracellular polymeric substances (EPS), reducing particle escape and enhancing settling performance. The treatment achieved the best COD, SS, and turbidity removal rates, reaching 85.64%, 93.29%, and 86.31%, respectively.

[0011] Preferably, the number of viable bacteria in the biocoagulant in the above treatment method is ≥ 1×10 7 cfu / mL, the dosage is 0.5%~3%, and the preferred dosage is 2.5%.

[0012] Preferably, the modified organic coagulant in the above treatment method is starch modified with 2,3-epoxypropyltrimethylammonium chloride (GTA); The inorganic coagulant is polyferric sulfate.

[0013] The above-mentioned organic-inorganic-biological coagulant compound effectively improves the coagulation capacity. This is because ST-g(GTA)-PFS can neutralize the charge of Fe by the quaternary ammonium group. 3+ The coordination ability of the microorganisms can quickly adsorb colloidal particles and macromolecular organic matter to form a primary floc skeleton. The microbial community secretes EPS to further adhere to soluble organic matter through adsorption and electrical neutralization.

[0014] Further preferably, the total dosage of the compounded modified organic coagulant and inorganic coagulant in the above treatment method is 1.5-3 g / L; The addition ratio of the compounded modified organic coagulant and the inorganic coagulant is 1:1 to 1:4.

[0015] The pH value of the compounded modified organic coagulant and inorganic coagulant is 7.5-8.5.

[0016] Preferably, the total dosage of the compounded modified organic coagulant and inorganic coagulant in the above treatment method is 2 g / L, the addition ratio of the organic coagulant to the inorganic coagulant is 1:3, and the pH is 8.

[0017] The present invention has found that the compounding scheme of the above-mentioned organic coagulant and inorganic coagulant has the best coagulation effect.

[0018] Preferably, the stirring in the above treatment method is performed twice, the first time is rapid stirring, and the second time is slow stirring; The rapid stirring rate is 300-400 r / min, and the time is 1-5 min; The slow stirring rate is 50-70 r / min, and the time is 5-10 min; The standing time is 15 to 25 minutes.

[0019] The present invention also provides a biocoagulant in the above treatment method, wherein the preparation method of the biocoagulant comprises: Bacillus megaterium and Bacillus subtilis were inoculated into seed culture medium separately and activated and amplified in a constant temperature shaking incubator at 33-37°C and 100-200 rpm for 24-36 hours. The two strains were then mixed and inoculated into the fermentation medium at a ratio of 1% by volume. The microorganisms were further cultured in a constant temperature shaking incubator at 33-37°C and 100-200 rpm. The seed culture medium comprises: NB medium: 5.0 g peptone, 3.0 g beef extract powder, 5.0 g sodium chloride, 1000 mL distilled water.

[0020] LB medium: peptone 10.0 g, yeast extract powder 5.0 g, sodium chloride 10.0 g, distilled water 1000 mL; The Bacillus megaterium seed culture medium is NB culture medium, and the Bacillus seed culture medium is LB culture medium; The fermentation medium includes: 20.0 g of sucrose, 2.0 g of yeast extract, 1.0 g of urea, 2.0 g of potassium dihydrogen phosphate, 2.0 g of dipotassium hydrogen phosphate, 100.0 g of sodium chloride, 0.2 g of magnesium sulfate heptahydrate, and 1000 mL of distilled water.

[0021] Preferably, the pH of the fermentation medium is 8, and the culture time in the fermentation medium is 48 hours.

[0022] The present invention found that a 1:1 mixture of the above-mentioned Bacillus megaterium and Bacillus followed by fermentation would have a better extracellular polymeric substance (EPS) production effect, which is more conducive to improving the biocoagulation effect of the final culture solution.

[0023] In the examples of the present invention, it was found that the culture medium pH and culture time of the biocoagulant had a significant impact on the subsequent coagulation effect. After comprehensive consideration of the coagulation effect and cost factors, the fermentation pH was selected to be 8 and the fermentation time was 48 h.

[0024] The present invention further provides a modified organic coagulant in the above-mentioned treatment method, wherein the preparation method of the modified organic coagulant comprises: Heat the starch solution to 70°C while stirring, pour the 2,3-epoxypropyltrimethylammonium chloride solution into the starch solution, add 1 mol / L NaOH solution, react for 2-5 hours, precipitate with anhydrous ethanol, dry at 60°C to constant weight, and grind to obtain the product; Heat the starch solution to 70°C while stirring, pour the 2,3-epoxypropyltrimethylammonium chloride solution into the starch solution, add 1 mol / L NaOH solution, react for 2-5 hours, precipitate with anhydrous ethanol, dry at 60°C to constant weight, and grind to obtain the product; The mass ratio of the starch to 2,3-epoxypropyltrimethylammonium chloride and NaOH is 1:2 to 3:2; Preferably, the mass ratio of starch, 2,3-epoxypropyltrimethylammonium chloride, and NaOH is 3:2:0.04, the reaction time is 2 h, and the amount of NaOH solution added is 5 mL.

[0025] The present invention found that the ratio of starch and the modifier 2,3-epoxypropyltrimethylammonium chloride, the reaction time and the amount of the activator all affect the coagulation effect of GTA-modified starch. The GTA-modified starch using the above reaction ratio and parameters has the best coagulation effect.

[0026] In a second aspect, the present invention provides a sewage treatment agent, which contains the above-mentioned biological coagulant and the above-mentioned modified organic coagulant and inorganic coagulant; The inorganic coagulant is any one of polyferric sulfate, polyaluminum chloride, polyaluminum sulfate and polyferric chloride.

[0027] The present invention further provides the use of the sewage treatment agent in treating livestock and poultry manure, especially in treating pig manure.

[0028] The present invention solves the problems of poor water solubility and poor coagulation effect of natural polymer materials and successfully develops the application of natural polymer organic coagulants.

[0029] And it mainly uses environmentally friendly coagulants, and prepares new green coagulants through organic modification, inorganic and biological coagulants to effectively treat high-concentration organic wastewater.

[0030] The entire coagulation scheme shows good removal effect on organic wastewater with high suspended solids and high COD at a lower dosage.

[0031] The beneficial effects of the present invention include: The modification method of the natural polymer coagulant provided by the present invention not only solves the problems of low water solubility and inconvenience in use of natural polymers, but also increases the coagulability of the natural organic polymer coagulant by adding cationic monomers to the polymer long chain through graft copolymerization technology.

[0032] Compared to traditional compound coagulants, the present invention's combination of modified starch, iron salt, and biocoagulant further enhances pollutant removal, significantly decolorizing and deodorizing livestock and poultry manure, resulting in clearer effluent. Furthermore, the coagulant is easily degradable and non-toxic to the environment and human health.

[0033] The organic-inorganic-biological coagulant compound scheme of the present invention performs well in treating high-suspended solids and high-concentration organic wastewater such as livestock and poultry manure, and has a high removal efficiency for suspended solids and pollutants. At the optimal dosage, the COD, SS and turbidity removal effects reached 85.64%, 93.29% and 86.31%, respectively. The clear liquid obtained by solid-liquid separation after coagulation has a low COD content, reducing the load of subsequent standard discharge treatment. At the same time, the clear liquid can be returned to the field for utilization or prepared as liquid fertilizer, and the flocs produced can be recycled through anaerobic fermentation or aerobic composting, thereby achieving efficient treatment of raw livestock and poultry manure. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the technical solutions in the present invention or the prior art, a brief introduction is given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 The following are pictures of the starch material before and after modification (before modification (a) and after modification (b)).

[0036] Figure 2 Figure 2 shows the effect of the modified starch of the present invention on the coagulation treatment of pig manure (a) and its effect on the changes in COD, SS and turbidity of pig manure (b).

[0037] Figure 3 These are electron microscope scanning images of the starch of the present invention before and after modification (before modification (a) and after modification (b)).

[0038] Figure 4 (a) FTIR spectrum and (b) X-ray diffraction pattern of the starch before and after modification.

[0039] Figure 5 This is the hydrogen nuclear magnetic resonance spectrum of the modified starch of the present invention.

[0040] Figure 6 This is a diagram showing the coagulation effect of pig manure water during the coagulation process using different coagulants in the present invention.

[0041] Figure 7 The graphs show the changes in turbidity (a), SS (b), and COD (c) of pig manure during the coagulation process with different coagulants in the present invention.

[0042] Figure 8 The figure shows the effect of the biocoagulant alone or after the bacterial strains are mixed on the coagulation effect of pig manure. Figure 8 (a) is the apparent influence diagram, Figure 8 (b) shows the impact on COD, SS and turbidity.

[0043] Figure 9 The figure shows the effect of different pH values ​​on the changes of COD (a), SS (b) and turbidity (c) during the fermentation process of the present invention.

[0044] Figure 10 This is the effect of different fermentation times on the coagulation process during the fermentation process of the present invention on the growth curve (a), COD (b), SS (c), and turbidity (d).

[0045] Figure 11 The figure shows the effect of the dosage of the biocoagulant of the present invention on the changes of COD (a), SS (b) and turbidity (b) in the coagulation process of the organic-inorganic-biocoagulant.

[0046] Figure 12 This is a diagram showing the coagulation effects of different composite coagulants in the present invention on the coagulation process of pig manure.

[0047] Figure 13 The figure shows the effect of different compound coagulants on the changes of COD (a), SS (b) and turbidity (b) during the coagulation process of the present invention. DETAILED DESCRIPTION

[0048] To make the purpose, technical solutions and advantages of the present invention more clear, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings. Obviously, the embodiments described are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0049] Example 1 This example provides an experiment on starch modification and coagulation effect.

[0050] Modification experiment: Weigh 10g of 2,3-epoxypropyltrimethylammonium chloride (GTA) and dissolve it in a beaker, weigh 15g of starch and add it to the beaker, add 50ml of deionized water and heat in a water bath with stirring, raise the water temperature to 70℃ and pour the obtained GTA solution into the starch solution, add 1mol / L NaOH solution as a catalyst, and fully react for 2h to obtain the initial product, precipitate it in anhydrous ethanol, dry it in an oven at 60℃ to constant weight, and grind it to obtain a powder as a modified starch coagulant. Using orthogonal experiments, COD, SS and turbidity removal were used as evaluation indicators to comprehensively investigate the effects of the three influencing factors on the coagulation effect, namely the mass ratio of starch to GTA, the amount of catalyst added and the reaction. Set 4 levels (Table 1) respectively, and take L 16 4 3 The orthogonal table was used to form 16 groups of coagulation experimental schemes, thereby determining the best modification scheme.

[0051] Coagulation experiments: Pig manure from a Beijing piggery after solid-liquid separation was used as a representative sample to validate the synthesized modified material and explore its process. A six-axis mixer was used for coagulation experiments. 3g / L of modified starch was added for coagulation. The rapid stirring time was controlled at 3 minutes, the rapid stirring rate was 350 r / min, and the slow stirring time was controlled at 8 minutes, the slow stirring rate was 60 r / min. The mixture was allowed to stand for 20 minutes for solid-liquid separation. The supernatant was collected and analyzed to explore the coagulation effects under different modification conditions and determine the optimal modification parameters.

[0052] The apparent morphology of starch before and after modification is as follows Figure 1 As shown, it can be found that the apparent properties of starch have changed significantly, from the original white to beige.

[0053] Effect diagram of coagulation treatment of pig manure and its effect on COD, SS and turbidity of pig manure Figure 2 As shown in the figure, it can be found that the turbidity and color of the pig manure water after treatment with modified starch are greatly reduced, and the COD, SS and turbidity removal rates reach 64.1%, 92.3% and 98.5% respectively, indicating that this material has good coagulation performance and pollutant removal ability.

[0054] The scanning electron microscopy morphology of starch before and after modification is as follows Figure 3 As shown, it can be found that the surface of the starch molecules before modification is smooth and flat, and the particle size is relatively uniform, while the surface of the starch molecules after modification becomes rough.

[0055] FTIR spectra and X-ray diffraction patterns of starch before and after modification Figure 4 As shown, Figure 4The a indicates significant differences in the functional group structures before and after modification. The peak at 1648 cm⁻¹ corresponds to the C=N stretching vibration, a characteristic peak of the quaternary ammonium group. The COC stretching vibration peak at 1025 cm⁻¹ indicates the formation of new ether bonds in the modified starch, confirming the successful etherification reaction. Figure 3 It can be seen from b that the X-ray diffraction patterns before and after modification show that starch has obvious diffraction peaks in the range of 17.18° to 21.92° at 2θ, while the modified starch has no obvious diffraction peaks in this range, only bulging peaks, indicating that the crystalline structure of the modified starch has been completely destroyed and the crystals have been changed into amorphous.

[0056] The H NMR spectrum of starch after modification is as follows Figure 5 As shown, the nuclear magnetic hydrogen spectrum shows that an absorption peak is found at δ = 3.20 ppm, which can be attributed to the absorption peak generated by the H atom connected to the trimethylammonium group (-N+(CH3)3) on the quaternary ammonium salt.

[0057] In summary, it was proved that starch was successfully modified to form ST-g(GTA).

[0058] The results of the orthogonal test are shown in Table 2. It can be seen from Table 2 that the mass ratio of GTA to starch, the amount of activator added, and the reaction time will significantly affect the coagulation effect, but the mass ratio has the greatest impact overall. After comprehensive consideration, A4B1C3, that is, the mass ratio of ST to GTA is 15:10, the reaction time is 2 h, and the activator dosage is 5 mL, was selected as the optimal parameters.

[0059] Example 2 This example provides an experiment on the effect of a combination of organic and inorganic coagulants on the coagulation of swine manure.

[0060] Experimental Design: Using pig manure from a pig farm in Beijing, we investigated the compound formula of modified chitosan (ST-g (GTA)) and inorganic coagulant. Using orthogonal design, COD, SS and turbidity removal rate were used as evaluation indicators to comprehensively investigate the effects of four factors on the coagulation effect, namely the type of inorganic coagulant, the total dosage of the coagulant, the dosage ratio and the pH value. Four levels were set (Table 3), and L 16 4 4An orthogonal table was created to generate 16 coagulation test plans for swine manure, thereby determining a combined organic-inorganic coagulation solution. The pH of the biogas slurry was adjusted with a 10% dilute sulfuric acid solution. Coagulation experiments were conducted using a six-stage mixer, with ST-g (GTA) and inorganic coagulants added. The rapid stirring time was controlled to 3 minutes at a rapid stirring rate of 350 r / min, while the slow stirring time was 8 minutes at a slow stirring rate of 60 r / min. The mixture was allowed to stand for 20 minutes for solid-liquid separation, and the supernatant was collected for analysis.

[0061] The results of the orthogonal test are shown in Table 4. After comprehensive consideration, the optimal compounding scheme was finally determined to be A3B4C2D4, that is, the type of inorganic coagulant was PFS, the compounding ratio was 1:3, the total dosage was 2 g / L, and the pH was 8.

[0062] The above optimal compound scheme was used to treat pig manure and compared with the use of organic and inorganic coagulants alone (dosage of each was 2g / L). The apparent results of each group are as follows: Figure 6 As shown, the changes of turbidity, SS and COD in each group are as follows Figure 7 shown.

[0063] Depend on Figure 6 It can be seen that the raw pig manure liquid is relatively turbid, all kinds of coagulants have floc sedimentation, and the color and turbidity of the supernatant are reduced, but the organic-inorganic composite scheme ST-g(GTA)-PFS has the best treatment effect.

[0064] Depend on Figure 7 It can be seen that the SS, turbidity and COD contents of the supernatant decreased significantly after treatment with different coagulants. Among them, the removal effect of organic-inorganic coagulants was better, with the removal rates of SS and turbidity reaching more than 90%, and the COD removal rate reaching 79.02%, indicating that the new coagulant has a better removal effect on suspended solids and organic pollutants, which is better than a single coagulant.

[0065] Example 3 This example provides an experiment on the effect of bacterial composition of biocoagulants on the coagulation effect of pig manure.

[0066] The preserved Bacillus and Bacillus megaterium strains were taken out and inoculated into the corresponding seed culture medium. The seed culture medium for Bacillus megaterium was NB medium, and the seed culture medium for Bacillus was LB medium. -1 The cells were activated and amplified in a constant temperature shaking incubator for 24-36 hours. The strains were inoculated into the fermentation medium at a volume ratio of 1% alone or in a mixture and incubated at 35°C and 150 rpm.-1 The cultured microbial solution was added to pig manure water at a volume ratio of 1% to conduct a coagulation test.

[0067] NB medium: 5.0 g peptone, 3.0 g beef extract powder, 5.0 g sodium chloride, 1000 mL distilled water.

[0068] LB medium: peptone 10.0 g, yeast extract powder 5.0 g, sodium chloride 10.0 g, distilled water 1000 mL; Bacillus and Bacillus megaterium were added alone or mixed and then added to pig manure for coagulation test. The results were as follows: Figure 8 shown.

[0069] Depend on Figure 8 As shown by a, thin, fine flocs formed at the bottom of all three treatments, while the flocs produced by the mixed culture were larger than those produced by the individual cultures. The COD and SS removal rates of the mixed culture microbial coagulant were higher than those of the individual cultures, likely due to the complementary metabolism of Bacillus and Bacillus megaterium, which secreted a wider variety of EPS.

[0070] Depend on Figure 8 It can be seen from b that the removal effect of mixed culture biocoagulant on COD, SS and turbidity is stronger than that of single use.

[0071] Example 4 This example provides an experiment on the effect of an organic-inorganic-biological compound solution on the coagulation of swine manure.

[0072] Microbial culture test: The two microorganisms were inoculated into the seed culture medium and cultured at 35℃ and 150 r·min. -1 The two strains were activated and amplified in a constant temperature shaking incubator for 24-36 hours. Subsequently, the two strains were inoculated into the fermentation medium at a volume ratio of 1% and mixed. The culture was carried out at 35°C and 150 rpm. -1 Under the conditions of , the microorganisms were continued to be cultured in a constant temperature shaking incubator.

[0073] Coagulation single factor test: Using pig manure from a pig farm in Beijing, on the basis of organic-inorganic coagulant compound, with COD, SS and turbidity removal rates as evaluation indicators, the fermentation time of the biocoagulant (12h, 24h, 36h, 48h, 60h, 72h, 84h), fermentation pH (5, 6, 7, 8, 9) and the dosage of the biocoagulant (0.5%, 1%, 1.5%, 2%, 2.5%, 3%) (volume ratio) were changed to further explore the compounding scheme of organic-inorganic-biocoagulant. A six-joint mixer was used for the coagulation experiment. The fast stirring time was controlled to be 3 min, the fast stirring rate was 350 r / min, the slow stirring time was 8 min, the slow stirring rate was 60r / min, and the solid-liquid separation was carried out after standing for 20 min. The supernatant was taken for analysis. The results are as follows. Figure 9 、 Figure 10 、 Figure 11 、 Figure 12 、 Figure 13 shown.

[0074] Depend on Figure 9 、 Figure 10 It can be seen that the coagulation effect of microbial coagulant is best when the fermentation pH is 8 and the fermentation time is 48h.

[0075] Depend on Figure 11 It can be seen that when the dosage of biocoagulant reaches 2.5%, the COD, SS and turbidity removal rates are all good, which is the optimal dosage.

[0076] Depend on Figure 12 It can be seen that the raw pig manure liquid is relatively turbid, and all kinds of coagulants have floc sedimentation, and the color and turbidity of the supernatant have decreased, but the treatment effect of the organic-inorganic-biological combination scheme is the best. The organic-inorganic-biological treatment produces larger and more stable flocs with a faster sedimentation rate. This may be because the chemical coagulant quickly builds a dense floc skeleton, and the biological coagulant fills the floc pores through the EPS adhesion effect, reduces particle escape, and enhances the sedimentation performance.

[0077] Depend on Figure 13The organic-inorganic-biological combination achieved the best removal rates for COD, SS, and turbidity, reaching 85.64%, 93.29%, and 86.31%, respectively. This indicates that the addition of the biocoagulant effectively enhanced the coagulation capacity of the original ST-g(GTA)-PFS. This is likely due to the rapid adsorption of colloidal particles and macromolecular organic matter by the charge neutralization of the quaternary ammonium groups and the coordination ability of Fe³⁺, forming a primary flocculent skeleton. The bacterial community then secretes EPS, which further adheres to dissolved organic matter through adsorption and charge neutralization. This demonstrates that the organic-inorganic-biological combination can effectively remove pollutants from pig water. This suggests that the organic-inorganic-biological coagulant is effective in removing suspended solids and organic pollutants, surpassing other combined coagulants.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the various embodiments of the present invention.

Claims

1. A method for treating livestock and poultry manure, characterized in that: include: First add biological coagulant to livestock and poultry manure, mix well, then add compound modified organic coagulant and inorganic coagulant, stir and let stand The biocoagulant contains Bacillus megaterium and Bacillus; The modified organic coagulant is modified starch; The inorganic coagulant is any one of polyferric sulfate, polyaluminum chloride, polyaluminum sulfate and polyferric chloride.

2. The processing method according to claim 1, characterized in that The number of viable bacteria in the biocoagulant is ≥1×10 7 cfu / mL, the dosage is 0.5%~3%, and the preferred dosage is 2.5%.

3. The processing method according to claim 2, characterized in that The modified organic coagulant is starch modified with 2,3-epoxypropyltrimethylammonium chloride; The inorganic coagulant is polyferric sulfate.

4. The processing method according to any one of claims 1 to 3, characterized in that The total dosage of the compounded modified organic coagulant and inorganic coagulant is 1.5-3 g / L; The addition ratio of the compounded modified organic coagulant and the inorganic coagulant is 1:1 to 1:4; The pH value of the compounded modified organic coagulant and inorganic coagulant is 7.5-8.

5.

5. The processing method according to any one of claims 1 to 4, characterized in that The stirring is performed twice, the first time is rapid stirring, and the second time is slow stirring; The rapid stirring rate is 300-400 r / min, and the time is 1-5 min; The slow stirring rate is 50-70 r / min, and the time is 5-10 min; The standing time is 15 to 25 minutes.

6. The biocoagulant in the treatment method according to any one of claims 1 to 5, characterized in that The preparation method of the biocoagulant comprises: Bacillus megaterium and Bacillus subtilis were inoculated into seed culture medium separately and activated and amplified in a constant temperature shaking incubator at 33-37°C and 100-200 rpm for 24-36 hours. The two strains were then mixed and inoculated into the fermentation medium at a ratio of 1% by volume. The microorganisms were further cultured in a constant temperature shaking incubator at 33-37°C and 100-200 rpm. The seed culture medium comprises: NB medium: 5.0 g peptone, 3.0 g beef extract powder, 5.0 g sodium chloride, 1000 mL distilled water. LB medium: peptone 10.0 g, yeast extract powder 5.0 g, sodium chloride 10.0 g, distilled water 1000 mL; The Bacillus megaterium seed culture medium is NB culture medium, and the Bacillus seed culture medium is LB culture medium; The fermentation medium includes: 20.0 g of sucrose, 2.0 g of yeast extract, 1.0 g of urea, 2.0 g of potassium dihydrogen phosphate, 2.0 g of dipotassium hydrogen phosphate, 100.0 g of sodium chloride, 0.2 g of magnesium sulfate heptahydrate, and 1000 mL of distilled water.

7. The biocoagulant according to claim 6, characterized in that The pH of the fermentation medium is 8, and the culture time in the fermentation medium is 48 hours.

8. The modified organic coagulant in the treatment method according to any one of claims 1 to 5, characterized in that: The preparation method of the modified organic coagulant comprises: Heat the starch solution to 70°C while stirring, pour the 2,3-epoxypropyltrimethylammonium chloride solution into the starch solution, add 1 mol / L NaOH solution, react for 2-5 hours, precipitate with anhydrous ethanol, dry at 60°C to constant weight, and grind to obtain the product; The mass ratio of the starch to 2,3-epoxypropyltrimethylammonium chloride and NaOH is 1:2 to 3:2; Preferably, the mass ratio of starch, 2,3-epoxypropyltrimethylammonium chloride, and NaOH is 3:2:0.04, the reaction time is 2 h, and the amount of NaOH solution added is 5 mL.

9. A sewage treatment agent, characterized in that: The sewage treatment agent contains the biological coagulant according to claim 6 or 7 and the modified organic coagulant and inorganic coagulant according to claim 8; The inorganic coagulant is any one of polyferric sulfate, polyaluminum chloride, polyaluminum sulfate and polyferric chloride.

10. Use of the sewage treatment agent according to claim 9 in treating livestock and poultry manure.

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