CN111943438A

CN111943438A - Biochemical treatment method for animal harmless treatment wastewater, nutrient solution prepared by biochemical treatment method and application of nutrient solution

Info

Publication number: CN111943438A
Application number: CN202010812069.XA
Authority: CN
Inventors: 王新丽
Original assignee: Individual
Current assignee: Individual
Priority date: 2020-08-13
Filing date: 2020-08-13
Publication date: 2020-11-17

Abstract

The invention relates to a biochemical treatment method for animal harmless treatment wastewater, nutrient solution prepared by the biochemical treatment method and application of the biochemical treatment method, and belongs to the technical field of fertilizer production. The biochemical treatment method comprises the following steps: digesting the animal harmless treatment wastewater at constant temperature to obtain sterilized wastewater; mixing the sterilized wastewater with bacillus subtilis, and carrying out biochemical reaction to obtain biochemical reaction liquid; inactivating the biochemical reaction solution to obtain an inactivated solution; filtering the inactivation solution to obtain a filtrate; adjusting the organic nitrogen content of the filtrate to be more than 120mg/L to obtain a blended liquid; removing impurities to obtain the nutrient solution after biochemical treatment. The method of the invention not only can solve the use problem of organic fertilizer for urban greening and flower planting, but also can solve the problem of recycling of waste water nutrition in harmless treatment of animal carcasses.

Description

Biochemical treatment method for animal harmless treatment wastewater, nutrient solution prepared by biochemical treatment method and application of nutrient solution

Technical Field

The invention relates to the technical field of fertilizer production, in particular to a biochemical treatment method for animal harmless treatment wastewater, a nutrient solution prepared by the biochemical treatment method and application of the biochemical treatment method.

Background

Urban greening is a blind area of fertilizer reduction, related actions are already carried out in agricultural rural areas in the agricultural field, and the fertilizer and pesticide reduction is promoted, so that soil land is protected and repaired, and agriculture can be developed sustainably. Modern urban development people pay attention to greening and flower cultivation, however, fertilizer technology in this aspect is concentrated on chemical fertilizers and compound fertilizers, so that desertification and salinization of urban soil are frequently caused. The lawn planting often has the conditions of withered and yellow, growth inhibition and the like, and meanwhile, the city is gradually cemented, people pay attention to the construction problem of the sponge city, however, one of the major obstacles is the problem of more and more urban greening soil. More noteworthy is that not only soil problems but also problems of fertilizer components permeating into underground water sources along with rainwater and irrigation, such as eutrophication, salinization, acidification and the like in underground water around cities are gradually revealed along with the fertilizer applied to greening and flower beds by people.

Therefore, the organic fertilizer used for urban greening is a hard demand of people for living, and although the organic fertilizer is also used for the urban greening in some places, the traditional organic fertilizer fermented by excrement is not completely fermented and has a large smell, so that the organic fertilizer is used for the urban greening and flower planting and has the smell influence.

Disclosure of Invention

The invention aims to provide a biochemical treatment method for animal harmless treatment of wastewater, a nutrient solution prepared by the biochemical treatment method and application of the biochemical treatment method. The method of the invention not only can solve the use problem of organic fertilizer for urban greening and flower planting, but also can solve the problem of recycling of waste water nutrition in harmless treatment of animal carcasses.

The invention provides a biochemical treatment method for animal harmless treatment of wastewater, which comprises the following steps:

stewing the animal harmless treatment wastewater at a constant temperature of 100-120 ℃ for 30-50 min to obtain sterilized wastewater;

mixing the sterilized wastewater with bacillus subtilis at 50-53 ℃, stirring, and carrying out biochemical reaction for 10-15 h to obtain biochemical reaction liquid;

inactivating the biochemical reaction solution at 100-120 ℃ for 10-30 min to obtain an inactivation solution;

filtering the inactivation solution to obtain a filtrate;

adjusting the organic nitrogen content of the filtrate to be more than 120mg/L and the pH value to be 3.0-9.0 to obtain a blended liquid;

and removing impurities from the blended liquid to obtain the nutrient solution after biochemical treatment.

Preferably, the constant temperature cooking is performed with continuous stirring.

Preferably, the content of viable bacteria in the bacillus subtilis is 2.0 x 10⁷cfu/g～3.5× 10⁷cfu/g。

Preferably, the mass of the bacillus subtilis is 0.02-0.1% of the sterilized wastewater.

Preferably, the method of adjusting the filtrate comprises adding water and/or adding a pH adjuster and/or a precipitant.

Preferably, the pH value of the prepared liquid is 6-7 after the liquid is diluted by 250 times.

The invention also provides the nutrient solution prepared by the biochemical treatment method in the technical scheme.

The invention also provides application of the nutrient solution in the technical scheme in preparation of organic fertilizers.

The invention provides a biochemical treatment method for animal harmless treatment of wastewater. The method of the invention can simultaneously solve the problem of urban harmless wastewater (sewage) and the problem of chemical fertilizer residue in urban greening. The invention utilizes the waste water generated in the harmless treatment of the urban animals to carry out recovery treatment, recycles the organic nutrient substances therein, solves the problem of ultrahigh BOD waste water treatment on one hand, improves the resource recycling effect on the other hand, and the waste water after biochemical treatment can be used for maintenance nutrition of urban lawns, flowers and trees to replace compound fertilizers (chemical fertilizers) so as to lead the urban greening to be organic and harmless; the fertilizer can also be used for planting nutrition supplement of vegetables, melons and vegetables, and can replace a chemical fertilizer or partially replace the chemical fertilizer, thereby being a good selection product for chemical fertilizer reduction work. The nutrient solution obtained by the method contains organic nutrients such as amino acid, micromolecular protein (less than 3000 daltons) and the like, the total organic nitrogen content is over 120mg/L, in addition, the nutrient solution also contains partial microelements such as calcium, iron, zinc, magnesium and the like due to high-temperature and high-pressure treatment, and the total content is less than or equal to 5 g/L.

The existing sewage treatment technology mainly aims at domestic sewage treatment, and high BOD and COD in sewage after the harmless treatment of urban animal carcasses are mainly used for decomposing organic matters in the sewage through the combined action of anaerobic bacteria and aerobic bacteria, so that the sewage treatment effect is achieved.

The invention decomposes valuable organic matters in the sewage by adopting a molecular biology technology and a microbial fermentation technology, reduces peculiar smell on one hand, and increases the absorption and utilization effects of plants on the other hand, so that the obtained plant nutrient solution can replace compound fertilizers and chemical fertilizers to be used for urban greening and flower planting, thereby solving the problem of urban greening. Further combining with plant nutrition technology, organic fertilizer solutions for agriculture are eagerly obtained.

The invention has the advantages that the detailed control of protein hydrolysis and biodegradation in molecular biology is utilized, the temperature, pH value, substrate concentration, fermentation process and the like of a biochemical reaction system are accurately regulated, and finally, the nutrition is not converted into carbon dioxide and water, but the protein is decomposed into amino acid and other nutritional ingredients.

Drawings

FIG. 1 shows the results of amino acid detection provided by the present invention.

Detailed Description

inactivating the biochemical reaction solution at 100-120 ℃ for 10min to obtain an inactivation solution;

filtering the inactivation solution to obtain a filtrate;

The animal harmless treatment wastewater is steamed and boiled at the constant temperature of 100-120 ℃ for 30-50 min to obtain the sterilized wastewater. The source of the animal harmless treatment wastewater is not particularly limited in the present invention, and wastewater from an animal harmless treatment plant known to those skilled in the art may be used. The animal harmless treatment wastewater is preferably urban animal harmless treatment wastewater. The animal harmless treatment wastewater is preferably heated to 100-120 ℃ under the operation of continuous stirring, and more preferably to 100 ℃. In the present invention, the time of the constant temperature cooking is more preferably 30min in the present invention, and the constant stirring is preferably performed during the constant temperature cooking. The constant-temperature cooking of the invention can remove most of mixed bacteria and improve the reaction effect of the bacillus subtilis.

After the sterilized wastewater is obtained, the sterilized wastewater is mixed with bacillus subtilis at the temperature of 50-53 ℃, preferably 51.5 ℃, stirred, and subjected to biochemical reaction for 10-15 hours, preferably 12.6 hours, so as to obtain a biochemical reaction solution. According to the invention, the temperature of the wastewater after sterilization is preferably maintained after the wastewater is cooled to 50-53 ℃. In the invention, the content of the viable bacteria of the bacillus subtilis is 2.0 multiplied by 10⁷cfu/g～3.5×10⁷cfu/g, more preferably 2.5X 10⁷cfu/g; the present invention preferably monitors and controls the progress of fermentation by measuring the amount of absorbed light of the fermentation broth with a spectrophotometer. In the present invention, the mass of the bacillus subtilis is preferably 0.02 to 0.1%, and more preferably 0.07% of the sterilized wastewater. The source of the Bacillus subtilis is not particularly limited in the invention, and a commercial product of the Bacillus subtilis for conventional agricultural fermentation, which is well known to those skilled in the art, can be adopted.

The microbial characteristics of the agricultural bacillus subtilis mostly survive in a spore form when the agricultural bacillus subtilis is stored at normal temperature, and the activation of the agricultural bacillus subtilis generally needs 2 hours. The growth of the activated bacillus subtilis is divided into a primary metabolism stage and a secondary metabolism stage, and a large amount of thalli are propagated in the primary stage by transferring nutrient substances in the environment. In the secondary stage, the reproduction speed of the thalli is reduced, and secondary metabolites begin to be metabolized. During mass propagation in the primary stage, a large amount of growth promoting factors can be produced and exist in the nutrient solution, and then the nutrition of macromolecular proteins is further changed into small molecules through microbial digestion. According to the invention, the setting of the addition conditions of the bacillus subtilis can be used for carrying out micro-fermentation on the wastewater by efficiently utilizing growth promoting factors and the like generated by the bacillus subtilis. The invention decomposes organic nutrition in the wastewater through the transformation of the bacillus subtilis, but does not excessively consume the nutrition. The invention utilizes molecular biology and microbial engineering, and changes the situation that the organic matters in the water body are thoroughly decomposed by using aerobic bacteria and anaerobic bacteria in the original wastewater treatment technology, so that the nutrition is wasted. According to the invention, the biochemical characteristics of protein molecules and polysaccharide molecules are utilized, bacillus subtilis is selected to optimize organic matter nutrition of the wastewater, so that part of protein is decomposed into small molecular protein and amino acid which can be absorbed and utilized by plants (part of protein can be decomposed, and some protein can be reserved), and thus, the wastewater subjected to harmless treatment is converted into nutrient solution or organic fertilizer which can be recycled, and the problems of root burning or over-fertilization and the like easily caused when the organic wastewater is used on the plants are avoided.

After the biochemical reaction solution is obtained, the biochemical reaction solution is inactivated for 10-30 min at 100-120 ℃ to obtain an inactivation solution. The biochemical reaction solution is inactivated at 100 ℃ for 10 min. After biochemical reaction, the temperature is raised, and the inactivation reaction is carried out by keeping the temperature at 100-120 ℃. The purpose of inactivation is to kill the bacillus subtilis.

After the inactivation solution is obtained, the inactivation solution is filtered to obtain a filtrate. The filtering mode is not particularly limited, and the conventional filtering method known to a person skilled in the art, such as bag filter filtering or plate-and-frame filter pressing, is adopted, the slag is filtered out through filter cloth of a filter screen, large impurities are filtered out, and the filtrate is taken for the next process. In the present invention, the filtration conditions are preferably 200 mesh.

After the filtrate is obtained, the organic nitrogen content of the filtrate is adjusted to be more than 120mg/L, the pH value is 3.0-9.0, and the blended liquid is obtained. In the invention, the method for adjusting the filtrate comprises adding water and/or adding a pH adjusting agent and/or a precipitating agent. The water is added to dilute the filtrate to prevent excessive viscosity, and the addition amount is preferably added according to the organic nitrogen content. The pH value of the liquid after blending is 3.0-9.0, the pH value range is large, the reason is that uncontrollable conditions of fermentation (biochemical reaction) are more, so that the pH value fluctuates, when the pH value is adjusted, in order to reduce the influence of microorganisms to the greatest extent, the pH value is adjusted to be slightly acidic or slightly alkaline to control the microorganisms, namely the pH value of the liquid after blending is more preferably 3-4, more hydrogen ions are provided in an acidic environment in a mother solution (filtrate) state, so that the amino acid exists stably in an acidic state, the growth of infectious microbes is inhibited, the diluted amino acid and water form alkalescence, and the pH value can be quickly recovered to be near neutral. The pH of the prepared liquid is preferably kept to be 6-7 after the liquid is diluted by 250 times. In the present invention, the pH adjuster preferably includes 6.5. In the invention, the precipitator preferably comprises polyaluminium chloride or ferrous sulfate, and the addition of the precipitator can flocculate and precipitate suspended thalli and impurities in the fermentation liquor, only reserve nutrient solution and prevent bacteria from excessively decomposing nutrition. According to the invention, impurities and insoluble substances can be separated out by adjusting the filtrate, namely adjusting the pH value and adding the precipitator, so that the (plant) nutrient solution which can be directly applied is obtained.

After the blended liquid is obtained, the blended liquid is subjected to impurity removal to obtain the nutrient solution after biochemical treatment. The impurity removal method preferably comprises the steps of sedimentation in a sedimentation tank or plate-and-frame filtration to remove impurities in the liquid. In the present invention, the impurities preferably include the cells of Bacillus subtilis, miscellaneous bacteria, fermentation metabolic debris, sticky substances, and the like.

The invention also provides the nutrient solution prepared by the biochemical treatment method in the technical scheme. The nutrient solution contains organic nutrients such as amino acid, micromolecular protein (less than 3000 daltons) and the like, the total organic nitrogen content is over 120mg/L, in addition, the nutrient solution also contains partial microelements such as calcium, iron, zinc, magnesium and the like due to high-temperature and high-pressure treatment, and the total content is less than or equal to 5 g/L. The nutrient solution of the invention has rich active growth promoting factors and is more beneficial to the utilization of nutrition of plants to promote the growth.

The invention also provides the nutrient solution prepared by the biochemical treatment method in the technical scheme or the application of the nutrient solution in the technical scheme in the preparation of organic fertilizer.

The animal carcass harmless treatment generally adopts a high-temperature high-pressure method, and the animal carcass is steamed at high temperature and high pressure, so that the aim of sterilization is fulfilled, and epidemic diseases caused by the animal carcass are avoided. The waste water mainly contains substances such as moisture, protein, soluble mineral substances, soluble polysaccharide and the like contained in animal carcasses, basically has no mixed bacteria, but some mixed bacteria are infected by the contact with air after the waste water is discharged from a reaction container, and meanwhile some impurities such as rust scraps of equipment are possibly brought in. According to the invention, the sewage is detected in the early stage, and the protein content is found to be 16.4-17.5%, and the organic matters are decomposed by conventional microbial sewage treatment in the traditional method, so that the odor near the sewage treatment is difficult to control, and the nutrition loss is serious. The invention recovers the nutrition for the plants as much as possible by a micro-fermentation mode, namely, the slight fermentation of the bacillus subtilis is carried out, the fermentation process is controlled, and the preliminary decomposition target of the bacillus subtilis is only reached, so that the nutrition is recovered as much as possible. After the micro-fermentation is finished, the odor problem can be solved by acidification and corrosion prevention or EM (effective microorganisms) treatment.

The biochemical treatment method for animal harmless wastewater, the nutrient solution prepared by the method and the application of the method are further described in detail with reference to the following specific examples, and the technical scheme of the invention includes but is not limited to the following examples.

Example 1

Raw materials: 300kg of sewage after harmless treatment of urban animal carcasses;

and (3) degerming: heating the materials to 100 deg.C under continuous stirring, and steaming at constant temperature for 30 min;

and (3) biochemical degradation: reducing the temperature of the materials, controlling the temperature at 50 ℃, adding 60g of bacillus subtilis, continuously stirring, and continuously carrying out biochemical reaction for 10 hours;

inactivation: after the biochemical reaction is finished, raising the temperature of the materials to 100 ℃, and maintaining for 10 min;

and (3) filtering: performing filter pressing by using a bag filter or a plate frame, filtering out slag materials through filter cloth of a filter screen, and enabling filtrate to enter the next process;

blending: adding water, pH regulator, precipitant, etc., and measuring organic nitrogen content to 130 mg/L; the pH value is about 3.50, and the pH value of the diluted 250-time solution is about 7;

removing impurities: filtering with a sedimentation tank or a plate frame to remove impurities in the nutrient solution;

filling and warehousing: and filling, packaging and sealing according to the product specification to obtain 320kg of nutrient solution, and warehousing and temporarily storing.

Example 2

Raw materials: 400kg of sewage after harmless treatment of urban animal carcasses;

and (3) biochemical degradation: reducing the temperature of the materials, controlling the temperature at 50 ℃, adding 100g of bacillus subtilis, continuously stirring, and continuously carrying out biochemical reaction for 12.5 h;

blending: adding water, pH regulator, precipitant, etc., and measuring organic nitrogen content to 135 mg/L; the pH value is 3.0, and the pH value of the diluted 250-time solution is about 6.5;

filling and warehousing: and filling, packaging and sealing according to the product specification to obtain 410kg of nutrient solution, and warehousing and temporarily storing.

Example 3

Raw materials: 500kg of sewage after harmless treatment of urban animal carcasses;

and (3) biochemical degradation: reducing the temperature of the materials, controlling the temperature at 53 ℃, adding 150g of bacillus subtilis, continuously stirring, and continuously carrying out biochemical reaction for 13 hours;

blending: adding water, a pH regulator, a precipitator and the like, and measuring the content of organic nitrogen to reach 140 mg/L; the pH value is about 3.50, and the pH value of the diluted 250-time solution is about 7;

filling and warehousing: and filling, packaging and sealing according to the product specification to obtain 550kg of nutrient solution, and warehousing and temporarily storing.

Example 4

and (3) biochemical degradation: reducing the temperature of the materials, controlling the temperature at 52 ℃, adding 180g of bacillus subtilis, continuously stirring, and continuously carrying out biochemical reaction for 15 h;

blending: adding water, a pH regulator, a precipitator and the like, and measuring the content of organic nitrogen to reach 140 mg/L; the pH value is about 3.50, and the pH value of the diluted 250-time solution is about 6.5-7;

Example 5

And (3) testing the fertility effect of the plant nutrient solution:

the root was applied by diluting 500 times with the nutrient solution having a pH of 3.5 and an organic nitrogen content of 130mg/L prepared in example 1.

The using method of the nutrient solution comprises the following steps: and (3) carrying out root irrigation or leaf surface spraying (leaf surface spraying is adopted for the pakchoi) by using a diluent of the nutrient solution once every 5-7 days, and not applying fertilizer in rainy days. The water is applied in the morning or evening in a time period with low temperature. The results are shown in tables 1 and 2.

TABLE 1 trial effect of pakchoi

TABLE 2 trial effect of forage type ryegrass

As can be seen from Table 1, the nutrient solution for pakchoi greatly reduces the amount of fertilizer used, increases the yield, reduces the growth cycle of pakchoi, improves the disease resistance, and reduces the amount of pesticide applied.

As can be seen from the table 2, the tests of the pasture show that the nutrient solution can accelerate the growth of the pasture, simultaneously improve the weight of each pasture, and lead the pasture to grow more robustly and have higher yield per mu. Has high market value.

FIG. 1 shows the results of free amino acid detection of samples of example 3, in which the alanine and lysine contents were high. The free amino acid is a single free amino acid decomposed by protein after enzymolysis and acidification, the molecular weight of the free amino acid is distributed between 180 and 280 daltons, the free amino acid is an organic nitrogen nutrient component, and the content of organic nitrogen is over 140mg/L according to a detection result.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims

1. A biochemical treatment method for animal harmless treatment of wastewater comprises the following steps:

filtering the inactivation solution to obtain a filtrate;

2. The biochemical treatment method according to claim 1, wherein the constant stirring is performed during the constant-temperature cooking.

3. The biochemical treatment method according to claim 1, wherein the viable bacteria content of Bacillus subtilis is 2.0X 10⁷cfu/g～3.5×10⁷cfu/g。

4. The biochemical treatment method according to claim 1, wherein the mass of the bacillus subtilis is 0.02 to 0.1% of the sterilized wastewater.

5. The biochemical treatment method according to claim 1, wherein the method of adjusting the filtrate comprises adding water and/or adding a pH adjuster and/or a precipitant.

6. The biochemical treatment method according to claim 1, wherein the pH of the prepared liquid after diluted 250 times is 6 to 7.

7. A nutrient solution prepared by the biochemical treatment method according to any one of claims 1 to 6.

8. Use of the nutrient solution of claim 7 in the preparation of an organic fertilizer.