Method for producing nutrient composition for plants and soil
阅读说明：本技术 植物和土壤用营养组合物的制造方法 (Method for producing nutrient composition for plants and soil ) 是由 苏希尔·K·巴拉 德文·K·胡珀 于 2019-07-30 设计创作，主要内容包括：本发明公开了从动物粪便制造用于植物和土壤的组合物例如液体生物肥料和固体生物刺激物的方法。所述方法包括向动物粪便的液体级分递送纯氧或富氧空气,并且还包括对所述液体级分进行自热嗜热好氧生物反应。还公开了通过这些方法制造的用于提高合成肥料在常规农业中的有效性和/或用于有机农业的营养组合物。(Methods of making compositions for plants and soil, such as liquid biofertilizers and solid biostimulants, from animal manure are disclosed. The method includes delivering pure oxygen or oxygen-enriched air to a liquid fraction of animal manure, and further includes subjecting the liquid fraction to an autothermal thermophilic aerobic biological reaction. Also disclosed are nutritional compositions made by these methods for improving the effectiveness of synthetic fertilizers in conventional agriculture and/or for organic agriculture.)
1. A method of manufacturing an organic fertilizer product from animal waste, the method comprising:
(a) adjusting the pH of the animal waste to about 5 to about 8 to produce a stable animal waste composition;
(b) adjusting the moisture content of the animal waste composition to at least about 75 wt% to produce an aqueous slurry;
(c) separating a substantially solid component and a substantially liquid component of the aqueous slurry; and
(d) subjecting said substantially liquid component to an autothermal thermophilic aerobic biological reaction comprising: (i) delivering pure oxygen or oxygen-enriched air to the substantial liquid component to maintain the substantial liquid component under aerobic conditions suitable for thermophilic bacterial growth for a first period of time; and (ii) maintaining the substantially liquid component at a temperature suitable for thermophilic bacterial growth for a second period of time; and is
Wherein the stable animal waste composition, the aqueous slurry, and the substantial liquid component are maintained at a pH of from about 5 to about 8 throughout the process.
2. The method of claim 1, further comprising:
(e) drying the substantially solid component to adjust the moisture content of the substantially solid component to less than about 15% to produce a dried solid product.
3. The method of claim 1 or claim 2, wherein the first time period and the second time period occur substantially simultaneously.
4. The method of claim 1, claim 2, or claim 3, further comprising mixing or chopping the stable animal waste composition, the aqueous slurry, or both the stable animal waste composition and the aqueous slurry.
5. The method of any one of the preceding claims, further comprising delivering pure oxygen or oxygen-enriched air to the aqueous slurry for a third period of time to reduce the concentration of anaerobic compounds in the aqueous slurry.
6. The method of claim 5, wherein the aqueous slurry comprises a residual dissolved oxygen concentration of at least about 1 part per million.
7. The method of claim 6, wherein the residual dissolved oxygen concentration is at least about 2 parts per million.
8. The method of any one of claims 5-6, wherein the anaerobic compound comprises hydrogen sulfide.
9. The method of any of claims 1-8, wherein the pure oxygen or oxygen-enriched air is delivered by injection through a sparger having one or more orifice levels in the range of about 1 micron to about 3 microns.
10. The method of any one of the preceding claims, wherein the pure oxygen or oxygen-enriched air is injected into the substantially liquid component at a rate of about 0.5CFM/1,000 gallons to about 1.5CFM/1,000 gallons.
11. The method of any one of claims 5-10, wherein the pure oxygen or oxygen-enriched air is injected into the aqueous slurry at a rate of about 0.25CFM/10,000 gallons to about 1.5CFM/10,000 gallons.
12. The method of any one of the preceding claims, wherein step (b) comprises adjusting the moisture content of the animal waste composition to between about 80% to about 92% by weight to produce an aqueous slurry.
13. The method of any one of the preceding claims, wherein the animal waste comprises poultry manure.
14. The method of any one of the preceding claims, wherein the poultry manure is chicken manure.
15. The method according to any one of the preceding claims, wherein the pH of the animal waste is adjusted by adding an acid.
16. The method of any one of the preceding claims, wherein the aqueous slurry is heated to between about 50 ℃ to about 80 ℃ prior to the separating step.
17. The process of any one of the preceding claims, wherein the autothermal thermophilic aerobic biological reaction comprises heating the substantially liquid component to a temperature of at least about 45 ℃ for the second period of time.
18. The process of any one of the preceding claims, wherein the aerobic conditions in the autothermal thermophilic aerobic biological reaction comprise a dissolved oxygen level of between about 2mg/l to about 6 mg/l.
19. The method of any one of the preceding claims, wherein the stable animal waste composition, the aqueous slurry, and the substantial liquid component are maintained at a pH of between about 5.5 to about 7 throughout the method.
20. The method of any one of claims 5-18, wherein the third period of time is at least about 15 minutes.
21. The method of claim 20, wherein the third period of time is at least about 1 hour.
22. The method of any one of the preceding claims, wherein both the first time period and the second time period are at least about 1 day.
23. The method of claim 22, wherein both the first time period and the second time period are at least about 3 days.
24. The method of any one of the preceding claims, further comprising:
prior to step (d), subjecting said substantial liquid component to an initial autothermal aerobic mesophilic reaction comprising (i) delivering pure oxygen or oxygen-enriched air to said substantial liquid component to maintain said substantial liquid component under aerobic conditions suitable for growth of mesophilic bacteria; and (ii) maintaining the substantially liquid component at a temperature suitable for growth of mesophilic bacteria; and is
Wherein the initial autothermal aerobic mesophilic reaction is maintained for at least about 1 hour.
25. The process of claim 24, wherein the initial autothermal aerobic mesophilic reaction is maintained for about 1 to 3 days.
26. A liquid fertilizer composition for application to plants and soil, wherein the liquid fertilizer composition is produced by the method of any one of claims 1-25.
27. The composition of claim 26, comprising at least one additive.
28. The composition of claim 27, wherein the additive is a macronutrient or a micronutrient.
29. The composition of any one of claims 26-28, formulated for application to soil or a medium in which plants are growing or will grow.
30. The composition of any one of claims 26-28, formulated for application to a seed or plant part.
31. The composition of any one of claims 26-28, which is suitable for use in organic projects.
32. The composition of any one of claims 26-28, wherein the composition is mixed with a synthetic fertilizer or a chemical fertilizer for use in conventional agriculture.
33. The composition of any one of claims 26-28, wherein the composition is mixed with a chemical pesticide and/or chemical herbicide for use in conventional agriculture.
34. A method for manufacturing a nutritional composition from animal waste, the method comprising:
(a) adjusting the pH of the animal waste to less than about 7.5 to produce a stable animal waste composition;
(b) adjusting the moisture content of the stabilized animal waste to at least about 80% by weight to produce an aqueous animal waste composition;
(c) separating a solid component and a liquid component of the aqueous animal waste composition; and
(d) subjecting the separated liquid component to an autothermal thermophilic aerobic biological reaction (ATAB) for a first predetermined time, wherein:
(i) the ATAB of the separated liquid component occurs in one or more bioreactors comprising a pure oxygen or oxygen-enriched air delivery system;
(ii) the delivery system injects the pure oxygen or oxygen-enriched air into the separated liquid component to maintain the separated liquid component under aerobic conditions suitable for thermophilic bacterial growth; and is
(iii) Maintaining the temperature of the separated liquid component in the bioreactor at a temperature between about 45 ℃ to about 75 ℃; and is
Wherein the stabilized animal waste composition, the aqueous animal waste composition, and the separated liquid component are maintained at a pH of less than about 7.5 throughout the process.
35. The method of claim 34, wherein the delivery system comprises one or more sprayers having a perforation level in the range of about 1 micron to about 3 microns.
36. The method of claim 34 or claim 35, wherein the pure oxygen or oxygen-enriched air is injected into the separated liquid component at a rate of about 0.5CFM/1,000 gallons to about 1.5CFM/1,000 gallons.
37. The method of any one of claims 34-36, wherein the first predetermined time is at least about 1 day.
38. The method of claim 37, wherein said first predetermined time is at least about 3 days.
39. The method of any one of claims 34-38, further comprising delivering pure oxygen or oxygen-enriched air to the aqueous animal waste composition for a second predetermined period of time.
40. The method of claim 39, wherein the second predetermined time is at least about 15 minutes and the delivery of pure oxygen or oxygen-enriched air is at a rate of about 0.25CFM/10,000 gallons to about 1.5CFM/10,000 gallons.
41. The method of any one of claims 34-40, wherein the temperature of the separated liquid component in the bioreactor is maintained at least about 60 ℃ for the predetermined period of time.
42. The method of any one of claims 34-41, wherein the bioreactor contains a foam level of less than about 1 foot during the first predetermined time period.
43. The method of any one of claims 34-42, further comprising:
prior to step (d), subjecting said substantial liquid component to an initial autothermal aerobic mesophilic reaction comprising: (i) delivering pure oxygen or oxygen-enriched air to the substantial liquid component to maintain the substantial liquid component under aerobic conditions suitable for growth of mesophilic bacteria; and (ii) maintaining the substantially liquid component at a temperature suitable for growth of mesophilic bacteria; and is
Wherein the initial autothermal aerobic mesophilic reaction is maintained for at least about 1 hour.
44. The process of claim 43, wherein the initial autothermal aerobic mesophilic reaction is maintained for about 1 to 3 days.
Technical Field
The present invention relates generally to fertilizers and compositions useful for promoting plant growth and healthy soil structure. In particular, methods of making such fertilizers and compositions are disclosed.
Background
Two main categories of crop inputs are used in agriculture: fertilizers and pesticides. Fertilizers are generally described as any organic or inorganic material of natural or synthetic origin that is added to provide one or more nutrients necessary for plant growth. Fertilizers provide macro-, medium-, and micro-nutrients needed or beneficial for plant growth in varying proportions.
Over the last century, synthetic fertilizers and pesticides have been widely used in agriculture. It is now well recognized that the use of synthetic fertilizers adversely affects the physical quality of the soil, reducing its ability to support plant productivity. In addition, the adverse Effects of these chemicals on the environment and humans are becoming increasingly recognized (see, e.g., Weisenberger, D.D., 1993, "impact of the Use of agrochemicals on Human Health" (Human Health Effects of agricultural Use), Hum. Pathol.24(6): 571-. In addition, numerous studies have shown that as soil carbon decreases, a significant increase in chemical fertilizer is required to maintain Yield, while it is estimated that 67% seed potential remains unrealized (see, e.g., Mulvaniy R.L. et al, 2009, J.environ.Qual.38(6): 2295-. Thus, the recognition of the generally detrimental effects of synthetic fertilizers and pesticides on soil ecology provides a drive to expand interest in sustainable and renewable crop production including the use of fertilizers, soil irritants and pesticides of natural and/or biological origin. Thus, the need for improved agriculture and crop protection is apparent in both organic and conventional agriculture fields, and highlights the need for biological treatments that can replace or supplement conventional synthetic fertilizers, or can be used in combination with conventional chemical herbicides/pesticides to maximize crop yield while maintaining soil integrity.
One class of materials that is considered for use in the agricultural industry as an alternative to synthetic fertilizers are agricultural biologies, such as biostimulants, biofertilizers, and biopesticides. In the agricultural industry, biofertilizers and biostimulants are used to add nutrients to plants and soil through the natural process of nitrogen fixation, phosphate solubilization and plant growth stimulation through the synthesis of growth promoting substances. Biofertilizers can be expected to reduce the use of chemical fertilizers and pesticides and are used in combination with pesticides in conventional agriculture to reduce, for example, chemical-induced stress on the plant itself. The microorganisms in the biofertilizer restore the natural nutrient circulation of the soil and build up soil organic matter. Healthy plants can be grown by using biofertilizers while enhancing the sustainability and health of the soil. In addition, certain microorganisms, known as Plant Growth Promoting Rhizobacteria (PGPR), are extremely advantageous in enriching soil fertility and satisfying plant nutrient requirements by providing organic nutrients via the microorganisms and their byproducts. Thus, biofertilizers do not contain any chemicals that are harmful to active soil.
In addition to providing benefits to the soil and rhizosphere, PGPR may affect plants in a direct or indirect manner. For example, they can directly enhance plant growth by providing nutrients and hormones to the plant. Examples of bacteria that have been found to enhance plant growth include certain mesophiles and thermophiles, including, for example, thermophilic members of the genera Bacillus (Bacillus), Ureibacillus (Ureibacillus), Geobacillus (Geobacillus), Brevibacillus (Brevibacillus), and Paenibacillus (Paenibacillus), all of which are known to be ubiquitous in poultry manure composting. Mesophiles reported to be beneficial for plant growth include mesophiles belonging to the genus Bacillus (Bacillus), Serratia (Serratia), Azotobacter (Azotobacter), Lysinibacillus (Lysinibacillus) and Pseudomonas (Pseudomonas).
PGPR is also able to control the number of pathogenic bacteria by microbial antagonism, which is achieved by competing with pathogens for nutrients, producing antibiotics, and producing antifungal metabolites. In addition to antagonism, certain bacterial-plant interactions can induce mechanisms that allow plants to better protect against pathogenic bacteria, fungi and viruses. One mechanism is called Induced Systemic Resistance (ISR) and the other mechanism is called Systemic Acquired Resistance (SAR) (see, e.g., Vallad, G.E., and R.M. Goodman,2004, Crop Sci.44: 1920-. Induced bacteria trigger a response at the root, producing signals that are transmitted throughout the plant, resulting in the activation of defense mechanisms, such as the enhancement of plant cell walls, the production of antimicrobial phytoalexins, and the synthesis of pathogen-associated proteins. Some components or metabolites of bacteria that can activate ISR or SAR include Lipopolysaccharide (LPS), flagella, salicylic acid, and siderophores. Thus, there remains a need for biofertilizers rich in nutrients and PGPR.
In addition to containing PGPR, the biofertilizer may also contain other types of bacteria, algae, fungi or combinations of these microorganisms, and include nitrogen-fixing microorganisms (e.g., Azotobacter (Azotobacter), Clostridium (Clostridium), Anabaena (Anabaena), Nostoc (Nostoc), rhizobiam (Rhizobium), Anabaena imbricata (Anabaena azolae) and Azospirillum (Azospirillum)), phosphorus-solubilizing bacteria and fungi (e.g., Bacillus subtilis, pseudomonas striata, Penicillium sp., Aspergillus awamori), phosphorus-mobilizing fungi (e.g., Glomus sp., dunaliella sp., proteus sp., Penicillium sp., cercospora sp., lactobacillus sp., limacinus sp., limnophora sp., and zinc solubilizing agents such as Bacillus subtilis). However, while biofertilizers may increase the availability of plant nutrients and aid in soil maintenance compared to conventional chemical fertilizers, the search for a cost-effective way to produce biofertilizers that are rich in suitable beneficial microbial populations and free of microbial contamination and other contaminants, and that can be used with existing application methods and techniques, remains a relatively unmet need in the industry.
One particular source of biofertilizer and biostimulant compositions is animal waste. In fact, animal manure and in particular poultry manure, which is rich in nutrients and microorganisms, has been the subject of extensive research with regard to its suitability as a biofertilizer. It is well established through academic research and farm trials that poultry manure can cost effectively provide all of the macro and micronutrients required for plant growth as well as certain plant-growth promoting rhizobacteria. However, these benefits are dependent on the elimination of plant and human pathogens associated with chicken manure. In addition, significant problems arising from the use of raw manure include increased potential for nutrient flow and high soil phosphorus leaching, as well as the transmission of human pathogens to food. Importantly, both U.S. producers and farmers must ensure that their manure-based biofertilizer meets strict safety regulations promulgated by the FDA regarding the unlimited use of manure-based inputs. See, e.g., 21c.f.r. § 112.51 (2016).
Another problem that adversely affects the agricultural industry is the contamination of the field with weed seeds. Furthermore, application based on faeces, in particular application of raw faeces, may actually result in contamination of Weed seeds, since undigested Weed seeds may be present in animal waste (see Katovich J. et al, "Survival of Weed seeds in Livestock Systems" (Weed Seed Survival in Livestock Systems), U.MIN.extension Servs. & U.Wis.extension, available at https:// www.extension.umn.edu/agriculture). Weed seed contamination often results in reduced yield in crops, promoting the need for increased application of chemical herbicides, which can have negative effects on both plant and human health. Weed seed contamination is particularly problematic in the organic agricultural industry where the application of synthetic herbicides is not permitted, forcing farmers to rely on mechanical scarifiers to control weed growth. Since composting has been shown to reduce the total amount of runoff and soil erosion as well as the potential for contamination by pathogens and weed seeds, many states now require composting of poultry manure prior to field application, resulting in advances in the composting process.
Composting can be described as the biological decomposition and stabilization of organic material. The process generates heat by microbial activity and produces a stable, essentially pathogen and weed seed free end product. As the product stabilizes, the odor will be reduced and the pathogens eliminated, indicating that the process has been performed. Most composting takes place in the solid phase.
The benefits of composting include: (1) enriching the soil with PGPR, (2) reducing microbes and other pathogens and killing weed seeds; (3) conditioning the soil to thereby increase plant accessibility to the nutrients; (4) potentially reducing runoff and soil erosion; (5) stabilizing volatile nitrogen in large protein particles to reduce losses; and (6) improving the water retention of the soil. However, the process is time consuming and labor intensive. Moreover, composting is not without major obstacles, including: (1) high efficiency composting requires large surface area; (2) in order to adequately compost for commercial use, heavy equipment is required to "turn over" the compost heap; (3) it is difficult to maintain a consistent, proper carbon to nitrogen ratio; (4) uniform heating is required; (5) transportation of bulky end products; (6) the products and their application lack consistency. In addition, since nutrients are applied in bulk prior to planting, there is a significant possibility that nutrients are lost through runoff. There is also a significant possibility of inconsistent decomposition and incomplete pathogen destruction. In addition, uneven nutrient distribution is also a problem in field applications. Finally, solid compost cannot be used for hydroponics and drip irrigation.
For this last disadvantage, both organic growers and traditional growers utilize compost leachate (compost tea) as liquid manure. The leachate is produced by soaking fully composted material in water and then separating the solids from the liquid leachate. Although this liquid material can be used for drip irrigation or foliar application, its production is still time consuming and labour intensive and the liquid product has the same disadvantages as solid compost, as it may still contain pathogenic organisms and its nutrient content is inconsistent. Thus, any residual pathogenic organisms present in the compost tea present a risk of pathogen replication and contamination and may therefore fail to pass inspection under applicable and stringent federal health and safety regulations.
Some organic fertilizers include fish-based and vegetable protein-based fertilizers. Fish emulsion products are typically produced from whole salt water fish and from debris products including fish bones, fish scales and fish skins. The fish is ground into a slurry and then heat treated to remove oil and fish meal. The liquid remaining after the process is called fish emulsion. The product is acidified to stabilize it and prevent microbial growth. Fish hydrolysate fertilizers are typically produced from freshwater fish by a cold enzyme digestion process. Although fish fertilizers can provide nutritional supplements for plants and soil microorganisms, they are difficult to use, in part because of their high acidity and in some cases oil-based composition, which can block agricultural equipment. Plant protein based fertilizers are typically produced by hydrolysis of protein rich plant materials such as soy and are an attractive alternative for growers and gardeners, for example, producing pure vegetarian products. However, due to their origin, these products can be expensive. Furthermore, none of the above fertilizers are natural biologicals: beneficial microorganisms must be added to them.
Liquid and solid nutrient rich biofertilizers can be produced from poultry manure using aerobic microorganisms that break down unwanted organic matter, such as the processes described in U.S. patent No. 9,688,584B2 and international patent application publication No. 2017/112605a 1. However, existing methods of processing poultry manure to produce biofertilizers suffer from a number of disadvantages including incomplete breakdown of organic matter and excessive foaming of the bioreactor equipment. The latter results in significant disruption of airflow and subsequent incomplete breakdown of organic matter, which often results in liquid fertilizer product clogging sprayers and other field application equipment, disrupting the operation of the farming program and increasing costs.
Accordingly, there remains a need in the art for more efficient methods for making products of biological origin that can provide excellent plant nutrition and soil conditioning while being safe, easy to use, and cost effective. Such products would provide a highly advantageous alternative to currently used synthetic products such as diammonium phosphate, monoammonium phosphate and urea-ammonium nitrate, and would meet the grower's requirements for standardization and reliability.
Disclosure of Invention
Described herein are methods for making compositions for application to plants and soil. In particular, the method produces solid and liquid compositions manufactured from animal waste, such as poultry manure. In one aspect, provided herein is a method of manufacturing an organic fertilizer product from animal waste, the method comprising the steps of: adjusting the pH of the animal waste to about 5 to about 8 to produce a stable animal waste composition; adjusting the moisture content of the animal waste composition to at least about 75 wt% to produce an aqueous slurry; separating a substantially solid component and a substantially liquid component of the aqueous slurry; and subjecting the substantially liquid component to autothermal thermophilic aerobic biological reactions. Further, the autothermal thermophilic aerobic biological reaction comprises delivering pure oxygen or oxygen-enriched air to the substantial liquid component to maintain the substantial liquid component under aerobic conditions suitable for the growth of thermophilic bacteria for a first period of time; and maintaining the substantially liquid component at a temperature suitable for thermophilic bacterial growth for a second period of time. Further, throughout the process, the stable animal waste composition, aqueous slurry, and substantial liquid components are maintained at a pH of from about 5 to about 8.
In another embodiment, the method further comprises the step of drying the substantially solid component to adjust the moisture content of the substantially solid component to less than about 15% to produce a dried solid product. In certain embodiments, the first time period and the second time period occur substantially simultaneously. In other embodiments, the method comprises mixing or chopping the stable animal waste composition, the aqueous slurry, or both the stable animal waste composition and the aqueous slurry.
In one embodiment, the method includes delivering pure oxygen or oxygen-enriched air to the aqueous slurry for a third period of time to reduce the concentration of anaerobic compounds in the aqueous slurry. In another embodiment, the aqueous slurry comprises a residual dissolved oxygen concentration of at least about 1 part per million. In certain embodiments, the residual dissolved oxygen concentration is at least about 2 parts per million. In addition, the anaerobic compound may include hydrogen sulfide. In certain embodiments, the pure oxygen or oxygen-enriched air is delivered by injection through a sparger having one or more orifice stages in the range of about 1 micron to about 3 microns. In another embodiment, the pure oxygen or oxygen-enriched air is injected into the substantially liquid component at a rate of about 0.5CFM to about 1.5CFM per 1,000 gallons. In still other embodiments, the pure oxygen or oxygen-enriched air is injected into the aqueous slurry at a rate of about 0.25CFM to about 1.5CFM per 10,000 gallons.
In various embodiments, the animal waste comprises poultry manure. For example, the poultry manure may be chicken manure. Furthermore, in some cases, the pH of the animal waste is adjusted by adding an acid. In some cases, the aqueous slurry is heated to between about 50 ℃ to about 80 ℃ prior to the separating step. In other embodiments, the autothermal thermophilic aerobic biological reaction comprises heating the substantially liquid component to a temperature of at least about 45 ℃ for the second period of time.
In any of the above embodiments, the aerobic conditions in the autothermal thermophilic aerobic biological reaction may have a dissolved oxygen level of between about 2mg/l and about 6 mg/l. In certain embodiments, the stable animal waste composition, aqueous slurry, and substantial liquid component are maintained at a pH of between about 5.5 to about 7 throughout the process.
In an exemplary embodiment, in the method, the third period of time is at least about 15 minutes. In other embodiments, the third period of time is at least about 1 hour. In the above methods, in some cases both the first time period and the second time period may be at least about 1 day. In still other embodiments, both the first and second time periods are at least about 3 days.
In another embodiment, the process comprises an additional step prior to the autothermal aerobic thermophilic reaction, which step comprises subjecting the substantial liquid component to an initial autothermal aerobic mesophilic reaction comprising: (i) delivering pure oxygen or oxygen-enriched air to the substantial liquid component to maintain the substantial liquid component under aerobic conditions suitable for growth of mesophilic bacteria; and (ii) maintaining the substantially liquid component at a temperature suitable for growth of mesophilic bacteria. In this embodiment, the initial autothermal aerobic mesophilic reaction is maintained for at least about 1 hour. In other embodiments, the initial autothermal aerobic mesophilic reaction is maintained for about 1 to 3 days.
In another aspect of the present invention, provided herein is a liquid fertilizer composition for application to plants and soil, wherein the liquid fertilizer composition is produced by any of the above methods. In certain embodiments, the composition comprises at least one additive, which may be a macronutrient or a micronutrient. In other embodiments, the composition is formulated for application to soil or culture medium in which plants are or will be growing. In yet other embodiments, the composition is formulated for application to a seed or plant part. In still other embodiments, it is suitable for use in organic projects. In certain embodiments, the composition is mixed with a synthetic or chemical fertilizer for use in conventional agriculture. In other embodiments, the composition is mixed with a chemical pesticide and/or chemical herbicide for use in conventional agriculture.
Another aspect of the invention describes a method of manufacturing a nutritional composition from animal waste, the method comprising the steps of: (a) adjusting the pH of the animal waste to less than about 7.5 to produce a stable animal waste composition; (b) adjusting the moisture content of the stabilized animal waste to at least about 80% by weight to produce an aqueous animal waste composition; (c) separating a solid component and a liquid component of the aqueous animal waste composition; and (d) subjecting the separated liquid component to an autothermal thermophilic aerobic biological reaction (ATAB) for a first predetermined time. In this case, the ATAB of the separated liquid component occurs in one or more bioreactors comprising a pure oxygen or oxygen-enriched air delivery system. Further, the delivery system injects the pure oxygen or oxygen-enriched air into the separated liquid component to maintain the separated liquid component under aerobic conditions suitable for thermophilic bacterial growth; and maintaining the temperature of the separated liquid component in the bioreactor at a temperature between about 45 ℃ to about 75 ℃. Further, throughout the process, the stable animal waste composition, aqueous animal waste composition, and separated liquid components are maintained at a pH of less than about 7.5.
In one embodiment, the delivery system comprises one or more sprayers having a perforation level in the range of about 1 micron to about 3 microns. In another embodiment, the pure oxygen or oxygen-enriched air is injected into the separated liquid component at a rate of about 0.5CFM to about 1.5CFM per 1,000 gallons. In still other embodiments, the first predetermined time is at least about 1 day. In still other embodiments, the first predetermined time is at least about 3 days.
In various other embodiments, the method comprises delivering pure oxygen or oxygen-enriched air to the aqueous animal waste composition for a second predetermined period of time. In certain versions of these embodiments, the second predetermined time is at least about 15 minutes and the delivery of pure oxygen or oxygen-enriched air is at a rate of about 0.25CFM to about 1.5CFM per 10,000 gallons.
In other embodiments, the temperature of the separated liquid component in the bioreactor is maintained at a temperature of at least about 60 ℃ for the predetermined period of time. In still other embodiments, the bioreactor comprises a foam level of less than about 1 foot during the first predetermined period of time.
In another embodiment, the process comprises an additional step prior to the autothermal aerobic thermophilic reaction, which step comprises subjecting the substantial liquid component to an initial autothermal aerobic mesophilic reaction comprising: (i) delivering pure oxygen or oxygen-enriched air to the substantial liquid component to maintain the substantial liquid component under aerobic conditions suitable for growth of mesophilic bacteria; and (ii) maintaining the substantially liquid component at a temperature suitable for growth of mesophilic bacteria. In this embodiment, the initial autothermal aerobic mesophilic reaction is maintained for at least about 1 hour. In other embodiments, the initial autothermal aerobic mesophilic reaction is maintained for about 1 to 3 days.
Other features and advantages of the present invention will be apparent by reference to the drawings, detailed description, and examples that follow.
Drawings
Fig. 1 is a block diagram of an exemplary embodiment of a method of producing a nutritional composition.
Fig. 2A is a graph showing the ATAB ORP in a bioreactor delivering ambient air. The y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and time in hours on the x-axis. The circles represent temperature over time, while the triangles represent ORP over time.
Fig. 2B is a graph showing the ATAB ORP in a bioreactor delivering ambient air. The Y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and the x-axis depicts time in hours. The circles represent temperature over time, while the triangles represent ORP over time.
Fig. 2C is a graph showing the ATAB ORP in a bioreactor delivering ambient air. The Y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and the x-axis depicts time in hours. The circles represent temperature over time, while the triangles represent ORP over time.
Fig. 2D is a graph showing the ATAB ORP in a bioreactor delivering ambient air. The Y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and the x-axis depicts time in hours. The circles represent temperature over time, while the triangles represent ORP over time.
Fig. 2E is a graph showing the ATAB ORP in a bioreactor delivering ambient air. The Y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and the x-axis depicts time in hours. The circles represent temperature over time, while the triangles represent ORP over time.
FIG. 3A is a graph showing the ATAB ORP in a bioreactor equipped with a pure oxygen delivery system. The Y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and the x-axis depicts time in hours. The circles represent temperature over time, while the triangles represent ORP over time.
FIG. 3B is a graph showing the ATAB ORP in a bioreactor equipped with a pure oxygen delivery system. The Y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and the x-axis depicts time in hours. The circles represent temperature over time, while the triangles represent ORP over time.
FIG. 3C is a graph showing the ATAB ORP in a bioreactor equipped with a pure oxygen delivery system. The Y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and the x-axis depicts time in hours. The circles represent temperature over time, while the triangles represent ORP over time.
FIG. 3D is a graph showing the ATAB ORP in a bioreactor equipped with a pure oxygen delivery system. The Y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and the x-axis depicts time in hours. The circles represent temperature over time, while the triangles represent ORP over time.
FIG. 3E is a graph showing the ATAB ORP in a bioreactor equipped with a pure oxygen delivery system. The Y-axis depicts temperature in degrees Celsius on the left and ORP in millivolts on the right, and the x-axis depicts time in hours. The circles represent temperature over time, while the triangles represent ORP over time.
Figure 4 is a graph comparing ATAB kinetics in a bioreactor supplying oxygen-enriched air compared to ambient air. The Y-axis depicts temperature in degrees fahrenheit and the x-axis depicts time in hours. The circles represent oxygen enriched air operation and the "+" represents ambient air operation.
Detailed Description
An improved method of producing compositions for plants and soil is described herein. The compositions produced by the processes and methods of the present disclosure include both liquid and solid products produced from animal manure and related waste as starting materials. Furthermore, the present disclosure provides a method for producing a biostimulant/biofertilizer product that is rich in microorganisms and nutrients, is environmentally safe, and is fully compatible with all precision agricultural application systems used in the organic, conventional and regenerative agricultural industries. Further, the compositions produced by the methods described herein include biofertilizers and biostimulants that allow for enhanced nutrient recycling and regeneration of soil carbon sources compared to chemical fertilizers.
In a particular embodiment, the starting material comprises poultry manure. The process described herein comprises separating a liquid fraction from an animal waste composition and subjecting the liquid fraction to autothermal thermophilic aerobic biological reactions (ATABs) by delivering pure oxygen or oxygen-enriched air to the liquid stream or component. The inventors have found that replacing conventional aeration or other methods using a source of atmospheric oxygen with a pure oxygen or oxygen-enriched source reduces the generation of foam during ATAB. This additional benefit allows for increased oxygen utilization during ATAB, thereby reducing evaporation, which in turn results in reduced heat loss, increased operating temperature range, and higher operating temperatures, thereby increasing decomposition of organic matter, resulting in a liquid fertilizer product with improved stability and shelf life and which is less likely to clog or clog spraying equipment during field application. Furthermore, the injection of pure oxygen or oxygen-enriched air into the animal waste composition during initial mixing and stabilization prior to separation prevents the formation of undesirable compounds formed by anaerobic fermentation of microorganisms, including the toxic and odor-causing hydrogen sulfide commonly found in animal waste. Exemplary animal waste suitable for use herein is poultry manure, especially poultry manure.
Poultry manure tends to have very high nitrogen, phosphorus and other nutrient content and a robust microbial community required for plant growth, and is therefore suitable for use in embodiments of the present invention. Table 1 shows a comparison of typical nutrient and microbial content in faeces from several different poultry species.
TABLE 1Poultry manure nutrient analysis (source: Biol.&Agric.Eng.Dept.NC State University,Jan 1994；Agronomic Division,NC Dept of Agriculture&Consumer Services)
TKN, total Kjeldahl nitrogen (organic nitrogen, ammonia and ammonium)
Accordingly, manure from domesticated birds or poultry may be particularly suitable for use in the manufacturing process of the present invention, as they tend to remain on farms and the like, making the source of goods abundant and convenient. In a particular embodiment, the poultry manure is selected from the group consisting of chicken (including hen), turkey, duck, goose and guinea fowl.
In a preferred embodiment, the raw manure used in the manufacturing process of the present invention comprises chicken manure. Chicken farms and other poultry farms may raise poultry as ground-fed poultry (e.g., turkeys, broilers, broiler breeder hens), where the manure is made up of animal manure or droppings, as well as bedding, feathers, and the like. Alternatively, poultry farms may raise poultry as caged layers raised from the ground, with the manure consisting primarily of manure droplets (manure and uric acid) falling through the cages. In particular instances, the chicken manure is selected from the group consisting of laying hens, broilers, and breeding hens. In a more particular embodiment, the feces comprise layer chicken feces.
Typical compositions of chicken manure are shown in table 2 (analyzed as a percentage or ppm of the total composition). The moisture content may vary from 45% to 70% moisture. In addition to macro and micronutrients, the feces contain diverse populations of microorganisms that have the potential to be PGPR and also have pathogenic characteristics. The manufacturing process is designed to reduce or eliminate pathogenic organisms and to culture beneficial organisms including PGPR.
TABLE 2Analysis of raw Chicken manure Nutrients
Nutrition
Mean value of
Range of
Ammonium nitrogen
0.88％
0.29-1.59％
Organic nitrogen
1.89％
0.66-2.96％
TKN
2.78％
1.88-3.66％
P2O5
2.03％
1.33-2.93％
K
1.40％
0.89-3.01％
Sulfur
0.39％
0.13-0.88％
Calcium carbonate
3.56％
1.98-5.95％
Magnesium alloy
0.36％
0.22-0.60％
Sodium salt
0.33％
0.10-0.88％
Copper (Cu)
90ppm
>20ppm-309ppm
Iron
490ppm
314ppm-911ppm
Manganese oxide
219ppm
100pm-493ppm
Zinc
288ppm
97ppm-553ppm
Moisture content
51.93％
31％-71％
Total solids
49.04％
69％-29％
pH
7.60
5.5-8.3
Total carbon
17.07％
9.10％-29.20％
Organic matter
22.32％
15％-30％
Ash content
19.00％
15-25％
Chlorine
0.39％
0.19％-0.80％
In certain embodiments, the selected poultry manure comprises between about 17 lb/ton and about 71 lb/ton (i.e., between about 0.85% and about 3.55% by weight) of Total Kjeldahl Nitrogen (TKN), which is the total amount of organic nitrogen, ammonia, and ammonium. In particular instances, the stool comprises a TKN of about 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, or 71 lb/ton.
The compositions of the present invention are produced from the animal waste by a process that combines physical (e.g., mechanical, thermal), chemical, and biological characteristics, as described in detail below, that reduces or eliminates pathogens while promoting the growth of a wide variety of microbial populations and producing metabolites of those microorganisms, which work together to promote plant and soil health. In this regard, the inventors controlled the time, temperature, redox potential value, and/or pH in various stages of the process, and could alter the microbiological and biochemical profile of the composition. Furthermore, the use of pure or enriched oxygen sources at various stages of the process has additional benefits, including preventing excessive foaming, increasing the oxygen flow to allow for more complete microorganism-mediated decomposition of organic matter, eliminating odor causing contaminants, and increasing the stability and shelf life of the final product.
While not wishing to be bound by theory, it is believed that the metabolites in the composition act as precursor building blocks for plant metabolism and may enhance regulatory function and growth. In one aspect, the bacteria in the composition can produce allelochemicals, which can include, for example, siderophores, antibiotics, and enzymes. On the other hand, precursor molecules for plant secondary metabolite synthesis may include flavonoids, combined phenol and polyphenol compounds, terpenoids, nitrogen-containing alkaloids, and sulfur-containing compounds.
All percentages mentioned herein are weight percentages (wt%), unless otherwise indicated.
Ranges, if used, are used as shorthand, to avoid having to list and describe each and every value that is within the range. Any value within the range can be selected as the upper limit, lower limit, or end point of the range, as appropriate.
The term "about" refers to a change in a value of a metric, such as temperature, weight, percentage, length, concentration, etc., that results from a typical error rate of the device used to obtain the metric. In one embodiment, the term "about" means within 5% of the reported numerical value.
As used herein, the singular form of a word includes the plural form and vice versa unless the context clearly dictates otherwise. Thus, no specific number of references will normally include the plural of the corresponding item. Likewise, the terms "comprise" and "or" should be construed as inclusive unless such an interpretation is explicitly prohibited in the context. Similarly, the term "example," particularly when followed by a list of terms, is merely exemplary and illustrative, and should not be deemed exclusive or comprehensive.
The term "comprising" is intended to include embodiments encompassed by the terms "consisting essentially of … …" and "consisting of … …". Similarly, the term "consisting essentially of … …" is intended to include embodiments encompassed by the term "consisting of … …".
As used herein, "animal waste" refers to any material containing animal waste, including litter, bedding, or any other environment in which animal waste is disposed. In one instance, the "animal waste" comprises bird or poultry manure, more particularly poultry manure (e.g., chicken, turkey, duck, goose, guinea fowl). In particular, "animal waste" includes chicken manure, such as manure from broiler chickens or layer chickens. In other instances, "animal waste" may refer to waste from other animals such as pigs, cattle, sheep, goats, or other animals not specifically enumerated herein. In yet another instance, "animal waste" can refer to a mixture of waste from two or more animals, such as two or more poultry.
The terms "enhanced effectiveness", "improved effectiveness", or "increased effectiveness" are used interchangeably herein and refer to the enhanced ability of biostimulants, synthetic fertilizers, chemical pesticides/herbicides, and other compounds to improve plant health, crop or seed yield, nutrient uptake or efficiency, disease resistance, soil integrity, plant response to stress (e.g., heat, drought, toxins), rolling leaf resistance, and the like. For example, an additive or supplement may be added to the biostimulant, synthetic fertilizer, or chemical insecticide/herbicide that provides "improved effectiveness" compared to the equivalent biostimulant, synthetic fertilizer, or chemical insecticide/herbicide in the absence of the additive. In particular, the biostimulant produced by the methods disclosed herein may be mixed with a synthetic fertilizer or herbicide/pesticide to provide improvements in plant health, crop or seed yield, nutrient uptake or efficiency, disease resistance, soil integrity, plant response to stress (e.g., heat, drought, toxins), rolling leaf resistance, etc., as compared to an equivalent plant or rhizosphere treated with the synthetic fertilizer or herbicide/pesticide in the absence of the biostimulant. The above plant and soil traits can be objectively measured by a skilled artisan using a number of standard techniques in the art suitable for such measurements.
"poultry litter" refers to a bed of material on which poultry is raised in a poultry raising facility. The litter may contain filler/bedding materials such as sawdust or wood shavings and chips, poultry manure, spilled food and feathers.
By "fecal slurry" is meant a mixture of feces with any liquid, such as urine and/or water. Thus, in one instance, a fecal slurry may be formed when animal feces comes into contact with urine or when the feces is mixed with water from an external source. The term slurry is not intended to imply any particular moisture and/or solids content.
The term "autothermal thermophilic aerobic biological reaction" or "ATAB" is used herein to describe a biological reaction carried out on the substantial liquid component of an animal manure slurry with the purpose of producing the liquid nutritional composition of the invention. As described below, the term refers to an exothermic process in which the separated liquid components of the animal waste slurry are subjected to elevated temperatures (at least partially produced endogenously) for a predetermined period of time. Organic matter is consumed by the microorganisms present in the original waste material and the heat released during microbial activity maintains thermophilic temperatures.
In this connection, a "biological reaction" is a biological reaction, i.e. a chemical process involving an organism or a biochemically active substance derived from such an organism. By "autothermal" is meant that the biological reaction produces its own heat. In the present disclosure, although heat may be supplied from an external source, the process itself also generates heat internally. By "thermophilic" is meant that the reaction favors the survival, growth and/or activity of thermophilic microorganisms. As is known in the art, thermophilic microorganisms are "thermophilic," as described in detail herein, and grow in a range between 45 ℃ and 80 ℃, more particularly between 50 ℃ and 70 ℃. By "aerobic" is meant that the biological reaction is carried out under aerobic conditions, in particular in favour of aerobic microorganisms, i.e. microorganisms that prefer (facultative) or require (obligatory) oxygen.
"anaerobic" means conditions that favor anaerobic microorganisms, which are facultative anaerobes, aerotolerant, or damaged by the presence of oxygen. An "anaerobic" compound is a compound produced by a microorganism during anaerobic respiration (fermentation).
As used herein, the term "pure oxygen" refers to a gas containing at least about 96% oxygen, typically in the range of about 96% to about 98% oxygen.
As used herein, the term "oxygen-enriched air" refers to air or gas containing at least about 30% oxygen.
The terms "ambient air" or "atmospheric oxygen" are sometimes used interchangeably herein and refer to air that is present on the earth in its natural state. The skilled artisan will readily appreciate that "ambient air" or "atmospheric oxygen" means air containing about 21% oxygen.
As used herein, the term "endogenous" refers to a substance or process that is produced internally, e.g., from the interior of a starting material, i.e., animal waste, or from the interior of a component of a manufacturing process, i.e., a separated liquid component, or from the interior of a product of a manufacturing process, i.e., a nutritional composition described herein. The composition may contain both endogenous and exogenous (i.e., added) components. In this regard, the term "endogenously comprising" refers to components that are endogenous to the composition and not added.
The terms "biocontrol agent" and "biopesticide" are used interchangeably herein to refer to pesticides derived from natural materials such as animals, plants, bacteria and certain minerals. For example, rapeseed oil and baking soda have insecticidal applications and are considered to be biopesticides. "biopesticides" include biochemical insecticides, microbial insecticides, and plant built-in protectants (PIPs). "biochemical pesticides" are naturally occurring substances that control pests through non-toxic mechanisms. "microbial insecticides" are insecticides containing a microorganism (e.g., a bacterium, a fungus, a virus or a protozoa) as an active ingredient. For example, in certain embodiments, Bacillus thuringiensis (Bacillus thuringiensis) subspecies and strains are used as "microbial pesticides". Bacillus thuringiensis (b.thuringiensis) produces a mixture of proteins that, depending on the particular subspecies or strain used and the particular protein produced, target insect larvae of certain species. A "PIP" is a pesticidal substance produced by a plant from genetic material added to the plant. For example, in certain embodiments, a gene for a bacillus thuringiensis (b.thuringiensis) insecticidal protein is introduced into the genome of a plant, which can be expressed by the plant to produce the protein.
As used herein, a "biostimulant" contains at least a carbon-based plant food source, and may also include other substances that, when applied to a plant or rhizosphere, stimulate existing natural biological and chemical processes in the plant to enhance and/or benefit nutrient uptake, nutrient efficiency, tolerance to abiotic stresses (e.g., drought, heat, and saline alkali soil), and/or crop quality. "biostimulants" comprising one or more primary nutrients (e.g. nitrogen, phosphorus and/or potassium) and at least one living microorganism are also biofertilizers. Other "biostimulants" may contain plant growth regulators, organic acids (e.g., humic and fulvic acids) and amino acids/enzymes.
As used herein, the term "biofertilizer" refers to a substance that contains one or more primary nutrients (e.g., nitrogen, phosphorus, and/or potassium) and viable microorganisms that, when applied to seeds, plant surfaces, or soil, colonize the rhizosphere or plant structure and promote growth by improving the accessibility of the primary nutrients to the host plant. "biofertilizers" include, but are not limited to, Plant Growth Promoting Rhizobacteria (PGPR), compost/compost tea and certain fungi (e.g., mycorrhiza). Examples of bacteria that have been found to enhance plant growth include both mesophilic and thermophilic bacteria. Specific thermophilic bacteria that have been shown to enhance plant growth include, for example, members of the genera Bacillus (Bacillus), Ureibacillus (Ureibacillus), Geobacillus (Geobacillus), Brevibacillus (Brevibacillus), and Paenibacillus (Paenibacillus), all of which are known to be ubiquitous in poultry manure composting. Mesophiles reported to be beneficial for plant growth include mesophiles belonging to the genus Bacillus (Bacillus), Serratia (Serratia), Azotobacter (Azotobacter), Lysinibacillus (Lysinibacillus) and Pseudomonas (Pseudomonas).
The term "mesophilic" is used herein to refer to the organism that grows best at moderate temperatures, typically between about 20 ℃ to about 45 ℃.
The term "organic fertilizer" generally refers to a soil amendment from natural sources that ensures at least a minimum percentage of nitrogen, phosphorus and potassium fertilizers. Examples include plant and animal by-products, rock flour, seaweed, inoculants and conditioners. Such fertilizers may also be said to have been registered, approved or listed for use in organic projects such as NOPs if they meet the criteria for such projects.
"plant growth promoting rhizobacteria" and "PGPR" are used interchangeably herein to refer to soil bacteria that colonize plant roots and enhance plant growth.
"plant growth regulator" and "PGR" are used interchangeably herein to refer to chemical messengers (i.e., hormones) for cell-cell communication in plants. There are currently five recognized classes of phytohormones or PGRs in the art: auxins, gibberellins, cytokinins, abscisic acid, and ethylene.
The term "organic agriculture" is used herein to refer to production systems that maintain soil and plant health by applying low environmental impact technologies that do not use chemical or synthetic products that may impact end-product, environmental, or human health.
The term "conventional agriculture" is used herein to refer to production systems that include the use of synthetic fertilizers, pesticides, herbicides, genetic modifications, and the like.
The term "regenerative agriculture" is used herein to refer to a system that enhances biodiversity, fertilizes soil, improves watershed, and enhances the planting principles and practices of ecosystem services.
As used herein, the term "rhizosphere" refers to the area of soil near the roots of plants in which chemistry and microbiology are affected by the growth, respiration, and nutrient exchange of the plant.
As used herein, a "soil conditioner" is a substance added to soil to improve the physical, chemical or biological qualities of the soil, particularly its ability to provide nutrition to plants. Soil conditioners may be used to improve poor soils or to rebuild soils that have been damaged by improper management. Such improvements may include increasing soil organic matter, improving soil nutrient distribution, and/or increasing soil microbial diversity.
Throughout this specification various publications are referenced including patents, published applications and academic papers. Each of these publications is incorporated by reference herein in its entirety.
Method：
The manufacturing method comprises the following steps: (1) preparing a starting material (animal waste, also referred to herein as "feed material"); (2) separating the prepared feed material into a substantially solid and a substantially liquid component; (3) drying the substantially solid component to produce the solid nutritional composition of the invention; (4) subjecting the substantially liquid component to an autothermal thermophilic aerobic biological reaction (ATAB); and (5) subjecting the bioreaction liquid product to one or more additional processing steps including filtration, pasteurization and formulation by addition of other components. A schematic diagram depicting an exemplary embodiment of a manufacturing process applied to layer manures is shown in fig. 1 and described in example 1. If the manure is supplied as poultry litter, for example from broiler chickens, the litter is removed before the process outlined above is started.
As mentioned above, the manufacturing methods disclosed herein may include an oxygen supply or delivery system for introducing pure oxygen or oxygen-enriched air having at least about 30%, e.g., at least about 30%, 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38%, 39%, 40%, 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48%, 49%, 50%, 51%, 52%, 53%, 54%, 55%, 56%, 57%, 58%, 59%, 60%, 61%, 62%, 63%, 64%, 65%, 66%, 67%, 68%, 69%, 70%, 71%, 72%, 73%, 74%, 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, to various steps in the method, An oxygen concentration of 92%, 93%, 94%, 95%, 95.5%, 96%, 96.5%, 97%, 97.5%, 98%, 98.5%, 99%, 99.1%, 99.2%, 99.3%, 99.4%, 99.5%, 99.6%, 99.7%, 99.8%, or 99.9%. Suitable oxygen supply systems may be installed in mixing tanks, bioreactors, etc. Such an oxygen supply system may be installed in place of typical nozzle mixers and aeration devices that supply atmospheric oxygen (or ambient air). Typically, atmospheric oxygen is air or gas having an oxygen content of about 21%, which is significantly lower than the oxygen supply provided in the process of the present invention. Pure oxygen or oxygen-enriched air may be introduced into the slurry preparation step, the ATAB step and/or the post-manufacture liquid fertilizer storage tank. Furthermore, pure oxygen or oxygen-enriched air can be injected into the slurry during storage prior to separation, if desired.
As will be appreciated by those skilled in the art, the gas may be delivered or injected into the liquid by a variety of different delivery devices, such as aspirators, venturi pumps, spargers, bubblers, carbonators, lines or pipes, tanks/cylinders, and the like. In a particular embodiment, the gas delivery device is a sparger. A sparger suitable for use with the oxygen supply system disclosed herein can be constructed of any art-standard porous structure of plastic (e.g., polyethylene or polypropylene) or metal (e.g., stainless steel, titanium, nickel, etc.). A pressurized gas (e.g., oxygen) may be forced through the network of perforations in the sparger and into the aqueous mixture, e.g., slurry or liquid fraction. Suitable mesh levels for use in the present invention are in the range of about 0.1 microns to about 5 microns, for example about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.0, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, or 5 microns; preferably between about 1 and 3 microns. In certain embodiments, the sprayer has an orifice size of about 1.5 microns to about 2.5 microns. For example, in one embodiment, the oxygen supply system comprises a 2 micron sintered stainless steel sparger.
In the preparation step, the moisture content and pH of the feed material are first adjusted. The moisture content is adjusted by adding a liquid to form an aqueous slurry that is sufficiently liquid that it can flow, for example by pumping, from one vessel to another via a hose or line. In certain embodiments, the aqueous slurry has a moisture content of at least about 80%. More specifically, the slurry has a moisture content of at least about 81%, or at least about 82%, or at least about 83%, or at least about 84%, or at least about 85%, or at least about 86%, or at least about 87%, or at least about 88%, or at least about 89%, or at least about 90%, or at least about 91%, or at least about 92%, or at least about 93%, or at least about 94%, or at least about 95%, or at least about 96%, or at least about 97%, or at least about 98%, or at least about 99%, and it should be understood that about 99% of the moisture is an upper limit. In particular embodiments, the slurry has a moisture content of between about 80% to about 95%, even more particularly between about 84% to about 87%, or between about 80% to about 92%.
During preparation, the pH of the feed material and/or slurry is adjusted to neutral or acidic by the addition of a pH adjusting agent, it being understood that the pH may be adjusted before or after moisture adjustment. Alternatively, the pH and moisture adjustments may occur simultaneously. Typically, the slurry needs to be acidified. In particular embodiments, the feed/slurry is adjusted to a pH of between about 4 to about 8, or more specifically between about 5 to about 8, or even more specifically between about 5.5 to about 7.5. In preferred embodiments, the pH of the slurry is about 6.0, or about 6.1, or about 6.2, or about 6.3, or about 6.4, or about 6.5, or about 6.6, or about 6.7, or about 6.8, or about 6.9, or about 7.0, or about 7.1, or about 7.2, or about 7.3, or about 7.4, or about 7.5. In certain embodiments, the slurry is adjusted to a pH of less than about 8, more preferably less than about 7.5. Acidification of otherwise non-acidic (i.e., basic) feed is important to stabilize the natural ammonia in the manure to non-volatile compounds such as ammonium citrate.
An acid is typically used to adjust the pH of the slurry. In certain embodiments, the acid is an organic acid, although inorganic acids may also be used or combined with organic acids. Suitable organic acids include, but are not limited to, formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, oxalic acid (oxalic acid), lactic acid (2-hydroxypropionic acid), malic acid (2-hydroxysuccinic acid), citric acid (2-hydroxypropane-1, 2, 3-tricarboxylic acid), and benzoic acid. Preferably, the acid is an acid commonly used to adjust the pH of food or feed. The preferred acid is citric acid.
It may also be desirable to reduce or prevent the production of anaerobic compounds produced during microbial fermentation under oxygen deprivation conditions. One of these unwanted compounds is hydrogen sulfide, which can be produced by anaerobic microbial breakdown of organic matter, such as feces. Hydrogen sulfide is toxic, corrosive and flammable, with the characteristic odor of rotten eggs. It is highly desirable to substantially reduce or eliminate the toxic and odor-causing hydrogen sulfide during the production of the liquid fertilizer product. The hydrogen sulfide that produces the odor can be oxidized by gaseous oxygen. For this purpose, slurry preparation may also include the delivery of oxygen to create a more aerobic environment to both prevent the formation of anaerobic contaminants and oxidize anaerobic contaminants.
In the slurry or liquid component, the hydrogen sulfide dissociates into its ionic form as shown in equation 1:
H2S→2H++S-2equation 1
The sulfide ions are then free to react with oxygen according to equation 2:
2H2S+O2→2H2o +2S equation 2
The reaction ratio of hydrogen sulfide oxidation is about 1.0. For example, 1mg/kg (ppm) of oxygen is required per ppm of hydrogen sulfide. In certain embodiments, the residual dissolved oxygen in the slurry or liquid component is at least about 0.5ppm, such as ppm of 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0 or higher. In a preferred embodiment, the residual dissolved oxygen level in the slurry or liquid component is at least about 1ppm, more preferably at least about 2 ppm. However, typical slurry mixing tanks supply atmospheric oxygen to the system to reduce the production of compounds formed by anaerobic metabolism of microorganisms. The atmospheric oxygen source may provide insufficient oxygen to eliminate hydrogen sulfide contaminants. Therefore, there is a need for more efficient oxygen delivery systems.
Thus, to oxidize hydrogen sulfide and other contaminants in the mix tank during slurry preparation, the preparation step may include an oxygen supply or delivery system for injecting pure oxygen or oxygen-enriched air into the slurry, which provides a substantial improvement in oxygen delivery over existing aeration devices that deliver atmospheric oxygen. The oxygen supply or delivery system may include any suitable means for delivering or injecting oxygen into the slurry, such as one or more spargers, venturi pumps, bubblers, carbonators, pipes, and the like. In certain embodiments, the oxygen supply or delivery system comprises a plurality of spargers. In certain embodiments, oxygen is delivered to the mixing tank of the preparatory step and/or injected directly into the slurry at a rate of about 0.1CFM to about 3CFM per 10,000 gallons of feedstock, e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0 CFM. In a preferred embodiment, the delivery rate is between about 0.25CFM to about 1.5CFM per 10,000 gallons of feedstock. For example, in one particular embodiment, oxygen is delivered to the mixing tank of the preparatory step and/or injected directly into the slurry at a rate of about 0.5CFM per 10,000 gallons of feedstock. Thus, the oxygen supply or delivery system disclosed herein increases the residual dissolved oxygen content to meet the desired threshold described above.
The slurry preparation system is designed to prepare a homogeneous slurry in an aqueous medium having a pH of 4 to 8, preferably 5 to 8, and at an elevated temperature. The temperature is raised at this stage for several purposes, including (1) to promote mixing and fluidity of the slurry, (2) to kill pathogens and/or weed seeds, and/or (3) to promote the growth of thermophilic and/or mesophilic bacteria present in the feed. The temperature may be raised by any means known in the art, including but not limited to conduction heating of the mixing tank, adjustment of moisture content using hot water, or injection of steam, to name a few. In certain embodiments, the slurry potassium channel is at least about 60 ℃, or at least about 61 ℃, or at least about 62 ℃, or at least about 63 ℃, or at least about 64 ℃, or at least about 65 ℃, or at least about 66 ℃, or at least about 67 ℃, or at least about 68 ℃, or at least about 69 ℃, or at least about 70 ℃. Typically, the temperature does not exceed about 80 ℃, or more specifically it is about 75 ℃ or less than about 70 ℃. In certain embodiments, the temperature of the slurry is maintained between about 65 ℃ to about 75 ℃.
Maintaining the pH adjusted aqueous slurry at an elevated temperature for a sufficient time to break down the manure into fine particles, sufficiently homogenize the slurry for further processing, kill pathogens and weed seeds, and/or activate indigenous thermophilic (and/or mesophilic) bacteria. In certain embodiments, the slurry is maintained at the elevated temperature for at least about 1 hour up to about 4 hours, for example about 1, 1.5, 2, 2.5, 3, 3.5, or 4 hours. Typically, the slurry is chopped, mixed and/or homogenized during this period. In certain embodiments, the preparation steps as outlined above are separated from the subsequent steps of the method to reduce the likelihood that downstream process steps may be contaminated with the original stool.
In an exemplary embodiment, the slurry system consists of a tank (e.g., a steel or stainless steel tank) equipped with a chopper/homogenizer (e.g., a pulverizer or chopper pump), an oxygen supply system, pH and temperature control, and a biofiltration system for the off-gas.
An exemplary process consists of the following steps: the tank is filled with water, heated to 65 ℃ or higher, and the pH is lowered to 8 or lower, preferably in the range of 5-8, with citric acid. The chopper pump, oxygen supply system (e.g., via sparger), and tail gas biofiltration system are turned on and the feed is then introduced to ensure a moisture content of, for example, 85 to 90%. This is a batch operation and can take from 1 to 4 hours to make a homogeneous slurry in each case. The operation ensures that each particle of the manure is subjected to a temperature of 65 ℃ or higher for a period of at least 1 hour to kill substantially all pathogens and weeds. In addition, the injection of pure oxygen or oxygen-enriched air reduces or eliminates the toxic and odor-causing contaminants such as hydrogen sulfide produced by anaerobic fermentation.
In certain embodiments, the animal waste slurry prepared as described above is transferred from the slurry tank by pumping, for example using a screw pump. Screw pumps are particularly suitable devices for moving slurries that may contain foreign matter such as stones, feathers, wood chips, and the like. The transfer line may be directed into a vibrating screen, wherein the screen may be vibrated in either a vertical axial mode or a horizontal transverse mode. The selected shaker screen will have a suitable mesh size to ensure that larger material is excluded from the slurry stream. In one embodiment, the screen excludes material greater than about 1/8 inches in any dimension.
In certain embodiments, the slurry stream is directed to a storage tank, which may be equipped with a pH and temperature control and/or agitation system. In a particular embodiment, the storage tank may also be equipped with an oxygen supply system. In such embodiments, the slurry is maintained under aerobic conditions by injecting pure oxygen or oxygen-enriched air at a rate of from about 0.1CFM to about 3CFM per 10,000 gallons of slurry, e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0CFM per 10,000 gallons of slurry. Preferably, the pure oxygen or oxygen-enriched air is delivered to the slurry at a rate of about 0.25CFM to about 1.5CFM per 10,000 gallons of slurry, more preferably about 0.5CFM per 10,000 gallons of slurry. In certain embodiments, the oxygen is delivered by a plurality of spargers, such as the spargers described above. By maintaining the slurry under aerobic conditions, the formation of anaerobic compounds is avoided. Optionally, the tail gas is subjected to biological filtration or other treatment means. The slurry stream leaving the storage tank is sent to a separation system (e.g., centrifuge or belt filter press) for use in the next step of the process.
In the separation step, the slurry stream from the storage tank is pumped into a solid-liquid separation system, which may include, but is not limited to, mechanical screening or clarification. The purpose of this step is to reduce solids such as cellulose and hemicellulose materials that are not suitable for subsequent ATAB. Notably, a substantial portion of the phosphorus and calcium present in the feed in this step tends to separate from the solids. Suitable separation systems include centrifugation, fractional distillation, filtration (e.g., via a filter press), vibratory separators, settling (e.g., gravity settling), and the like. In certain embodiments, a two-step separation system may be used, such as a centrifugation step followed by a vibratory screen separation step.
In a non-limiting exemplary embodiment, the method utilizes a decanter centrifuge that provides continuous mechanical separation. The operating principle of a decanter centrifuge is based on gravity separation. Decanter centrifuges increase the settling rate by using continuous rotation to produce a gravitational force between 1000 and 4000 times the normal gravitational force. When subjected to such forces, the denser solid particles press outwardly against the rotating centrifuge cup wall, while the less dense liquid phase forms a concentric inner layer. The depth of the liquid is varied as required using different slag traps. The sediment formed by the solid particles is continuously removed by a screw conveyor rotating at a different speed than the centrifuge cup. As a result, the solids gradually "plow" out of the pond and pile up into a conical "beach". Centrifugal force compacts the solids and expels excess liquid. The compacted solids are then discharged from the centrifuge cup. The one or more clarified liquid phases overflow over a weir at the opposite end of the centrifuge cup. Baffles within the centrifuge housing direct the separated phases into the correct flow path and prevent any risk of cross-contamination. The speed of the screw conveyor may be automatically adjusted using a Variable Frequency Drive (VFD) to accommodate changes in solids loading. In certain embodiments, a polymer may be added to the separation step to increase the efficiency of the separation and produce a drier solid product. Suitable polymers include polyacrylamides, such as anionic, cationic, nonionic, and zwitterionic polyacrylamides.
Thus, the separation process results in the formation of a substantially solid component and a substantially liquid component of the prepared animal waste slurry. The skilled artisan will appreciate that the term "substantial solid" means a solid having an amount of liquid therein. In particular embodiments, the substantially solid component may contain, for example, from about 40% to about 64% moisture, typically between about 48% to about 58% moisture, and is sometimes referred to herein as "solids," cake, "or" wet cake. Likewise, it should be understood that the term "substantially liquid" means a liquid having a quantity or amount of solids therein. In particular embodiments, the substantially liquid component may have between about 2% to about 15% solids (i.e., between about 85% to about 98% moisture), typically between about 4% to about 7% solids, and is sometimes referred to herein as "liquid," "liquid component," or "centrate" (the latter being used where the separation utilizes centrifugation). About 30% of the original feed remains in the substantial liquid component and about 70% remains in the cake.
Drying the solids from the separation step to a moisture content suitable for subsequent material handling and packaging. In certain embodiments, the solids from the separation step are dried at a temperature of less than about 220 ℃ and at a rate of about 900kg to about 2,700kg (wet weight) solids per hour for about 5 to 15 minutes, such as 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, or 15 minutes. Preferably, the maximum drying temperature is from 200 ℃ to about 220 ℃ at a rate of from about 1,500 to about 2,000kg solids per hour. In other embodiments, the solid is dried at a temperature between about 80 ℃ and about 230 ℃, e.g., 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃, 150 ℃, 155 ℃, 160 ℃, 165 ℃, 170 ℃, 175 ℃, 180 ℃, 185 ℃, 190 ℃, 195 ℃,200 ℃, 205 ℃, 210 ℃, 215 ℃, 220 ℃, 225 ℃, or 230 ℃. Suitable drying equipment is known to the skilled person and includes, for example, fluid bed dryers, vacuum dryers, flash dryers and rotary dryers. For example, in one particular embodiment, a fluidized bed dryer may be used to dry the solid component obtained from the separation step. In certain embodiments, the solid component is dried to less than about 20% moisture. In particular embodiments, the solid is dried to less than about 19%, or less than about 18%, or less than about 17%, or less than about 16%, or less than about 15%, or less than about 14%, or less than about 13%, or less than about 12%, or less than about 11%, or less than about 10% moisture. In a preferred embodiment, the solid component is dried to less than 12% moisture. For example, the drying step may be performed on a solid component having a moisture content of about 30% to about 55% for about 3-5 minutes to reduce the moisture content to about 10%. The dried solids are sometimes referred to herein as "dried cakes". The dried solids can be used as biostimulants to enhance the microbiome contributing to increased plant growth, resistance to stress, nutrient uptake and efficiency, etc.
In certain embodiments, the method of manufacture comprises a pelletizing step, whereby the solid material is made into a product suitable for use in agricultural and horticultural application spreaders. In such embodiments, the solid components from the separation step are fed to a combination cage mill/flash dryer and dried at a temperature in the range of from about 65 ℃ to about 220 ℃, preferably between about 200 ℃ to about 220 ℃. Reducing the solids to a consistent fineness of less than about 0.5mm, e.g., about 0.5mm, 0.4mm, 0.3mm, 0.2mm, 0.15mm, 0.1mm, 0.05mm or less, and a moisture content of less than or equal to about 25% moisture. Preferably, the solids are reduced to a consistent fineness of less than about 0.2mm and a moisture content of equal to or less than about 20% moisture. For example, in one particular embodiment, the solids are fed into a combination cage mill/flash dryer to produce a material having a fineness of less than about 0.177mm (about 80 mesh). The dried solids are then sent to a pin mixer and mixed with a suitable binder (e.g., molasses). In certain embodiments, the solid/binder mixture is granulated to a particle size suitable for an agricultural application spreader of from about 1mm to about 6mm, for example 1mm, 2mm, 3mm, 4mm, 5mm or 6 mm. Preferably, the particle size of the seed for agricultural applications is from about 2mm to about 4mm (about 5-10 mesh). In other embodiments, the solid/binder mixture is granulated to a particle size suitable for a horticultural application spreader (i.e. greenfield grade) of from about 0.1mm to about 2mm, for example 0.1mm, 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, 0.7mm, 0.8mm, 0.9mm, 1mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, 1.6mm, 1.7mm, 1.8mm, 1.9mm or 2 mm. Preferably, the greenfield grade particle size for the horticultural applicator spreader is from about 0.6mm to about 1.6mm (about 12-30 mesh). Passing the pellets to another dryer for final drying, where the pellets are dried to less than about 15% moisture, e.g., 15%, 14%, 13%, 12%, 11%, 10% or less moisture; preferably, the particles have a moisture content at this stage of equal to or less than about 12% moisture. The dried granules were then cooled and size sieved.
In certain embodiments, the manufacturing process is a closed loop system in which tail gas and water vapor from any or all stages of the system, including the dryer, are captured and condensed into a nutrient rich liquid form. This liquid may be re-integrated into the liquid manufacturing process described below, for example into the feed slurry, bioreactor or base product exiting the bioreactor.
The next step involves subjecting the substantially liquid component to an autothermal thermophilic aerobic biological reaction (ATAB). ATAB is an exothermic process in which the separated liquid component with finely suspended solids is subjected to elevated temperatures for a predetermined period of time. Organic matter is consumed by the microorganisms present in the raw waste material and the heat released during the microbial activity maintains mesophilic and/or thermophilic temperatures, thereby facilitating the production of mesophilic and thermophilic microorganisms, respectively. The autothermal thermophilic aerobic biological reaction produces a biologically stable product containing macro and micronutrients and PGPR.
In certain embodiments, the elevated temperature conditions are between about 45 ℃ to about 80 ℃. More specifically, the high temperature conditions are at least about 46 ℃, or 47 ℃, or 48 ℃, or 49 ℃, or 50 ℃, or 51 ℃, or 52 ℃, or 53 ℃, or 54 ℃, or 55 ℃, or 56 ℃, or 57 ℃, or 58 ℃, or 59 ℃, or 60 ℃, or 61 ℃, or 62 ℃, or 63 ℃, or 64 ℃, or 65 ℃, or 66 ℃, or 67 ℃, or 68 ℃, or 69 ℃, or 70 ℃, or 71 ℃, or 72 ℃, or 73 ℃, or 74 ℃, or 75 ℃, or 76 ℃, or 77 ℃, or 78 ℃, or 79 ℃. In particular embodiments, the elevated temperature conditions are between about 45 ℃ and about 75 ℃, more particularly between about 45 ℃ and about 70 ℃, more particularly between about 50 ℃ and about 65 ℃, and most particularly between about 55 ℃ and about 60 ℃.
Typically, the temperature of the ATAB is gradually increased to the mesophilic stage and then to the thermophilic stage. It will be appreciated by those of ordinary skill in the art that the mesophilic stage is at the temperature range where mesophilic bacteria grow best (e.g., about 20 ℃ to about 45 ℃). When the temperature is raised above 20 ℃ to about 40 ℃, the liquid component enters the mesophilic stage, thereby enriching mesophilic bacteria. In certain embodiments, the mesophilic temperature is between about 30 ℃ and about 40 ℃, e.g., about 30 ℃, 31 ℃,32 ℃, 33 ℃, 34 ℃, 35 ℃, 36 ℃, 37 ℃, 38 ℃, 39 ℃, or 40 ℃. In other embodiments, the mesophilic temperature is about 35 ℃ to about 38 ℃. In such embodiments, the liquid component is maintained at the mesophilic temperature for a period of 1 hour to several days, for example at least about 1 hour, 2 hours, 3 hours, 4 hours, 5 hours, 6 hours, 7 hours, 8 hours, 9 hours, 10 hours, 11 hours, 12 hours, 13 hours, 14 hours, 15 hours, 16 hours, 17 hours, 18 hours, 19 hours, 20 hours, 21 hours, 22 hours, 23 hours, 1 day, 2 days, 3 days, 4 days, or 5 days. In a preferred embodiment, the liquid component is maintained at the mesophilic temperature for a period of about 1 to 4 days, more preferably about 1 to 3 days. For example, in one particular embodiment, the liquid component is maintained at the mesophilic temperature for about 3 days. As the temperature continues to rise, the liquid component enters the thermophilic phase, thereby enriching for thermophilic bacteria. It will be appreciated by those of ordinary skill in the art that the thermophilic phase is at a temperature in the range where thermophilic bacteria grow best (e.g., about 40 ℃ to about 80 ℃). In certain embodiments, the thermophilic phase temperature is between about 45 ℃ and about 80 ℃, e.g., about 45 ℃, 46 ℃, 47 ℃, 48 ℃, 49 ℃,50 ℃, 51 ℃, 52 ℃, 53 ℃, 54 ℃, 55 ℃, 56 ℃, 57 ℃,58 ℃, 59 ℃, 60 ℃, 61 ℃, 62 ℃, 63 ℃, 64 ℃, 65 ℃, 66 ℃, 67 ℃,68 ℃, 69 ℃,70 ℃, 71 ℃, 72 ℃, 73 ℃, 74 ℃, 75 ℃, 76 ℃, 77 ℃, 78 ℃, 79 ℃ or 80 ℃. In other embodiments, the thermophilic phase temperature is from about 50 ℃ to about 70 ℃.
In certain embodiments, the liquid component is maintained at the elevated temperature for a period of time ranging from several hours to several days. A range between 1 day and 18 days is typically used. In certain embodiments, the conditions may be maintained for 1,2,3, 4, 5, 6, 7, 8, 9, or more days. The bioreaction is maintained at elevated temperatures for a longer period of time, e.g. 3 or more days, merely for instructional purposes, to ensure a suitable reduction of pathogenic organisms, e.g. to meet the guidelines for use on the food part of the crop. However, since the length of the bioreaction affects the biological and biochemical content of the bioreaction product, other times may be chosen, such as hours to 1 or 2 days. In particular embodiments, after being maintained at an elevated temperature suitable for thermophilic bacteria, the temperature of the liquid component is gradually reduced to within the mesophilic temperature range, at which point it is maintained at the mesophilic temperature until the liquid component is either rapidly pasteurized or run through a heat exchanger to rapidly reduce the temperature as described below, in many cases, either of which causes the bacteria to produce spores.
One challenge of operating under aerobic thermophilic conditions is to keep the process sufficiently aerobic by meeting or exceeding the oxygen demand while operating under elevated temperature conditions. One reason for this challenge is that as the process temperature increases, the saturation value of the residual dissolved oxygen decreases. Another challenge is that the activity of the thermophilic microorganisms increases within a gradually increasing temperature, resulting in an increase in oxygen consumption by the microorganisms. Due to these factors, in various situations, a greater amount of oxygen should be provided to the solution containing the biomass.
As described in WO 2017/112605a1, the contents of which are incorporated herein in their entirety, existing bioreactors use aeration devices such as jet ventilators to deliver atmospheric oxygen to the bioreactor due to high oxygen transfer efficiency, the ability to independently control oxygen transfer, superior mixing, and reduced off-gas production. However, the present inventors have found that atmospheric oxygen causes excessive foaming inside the bioreactor, hampering the oxygen supply efficiency and causing frequent shut-downs of the air supply. In some cases, for example, the level of foaming exceeds a few feet, such as 1,2,3, 4, 5, 6, 7, 8 feet or more. The insufficient air supply and reaction interruption in turn lead to an incomplete decomposition of the organic matter which is undesirable. Moreover, the increase in undecomposed solids suspended in the substantial liquid stream has proven to be difficult to remove and frequently results in liquid fertilizer clogging spray equipment during field application, thereby halting field operations. Furthermore, undecomposed solids present in the final liquid fertilizer product reduce stability and shelf life.
Thus, to overcome these obstacles, pure oxygen or oxygen-enriched air is delivered to the bioreactor and injected or otherwise delivered into the substantial liquid component at a rate of about 0.1CFM to about 5CFM per 1,000 gallons of liquid component, e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4.4, 4.0, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 4.4.4, 4.4, 4.5 gallons, 4.4, 4.8, 4.4.4, 4.8, 4.4, 4.8, 4, 4.8, 4.. In a preferred embodiment, the pure oxygen or oxygen-enriched air is delivered to the bioreactor and injected or otherwise delivered into the substantially liquid component at a rate of about 0.5CFM to about 1.5CFM per 1,000 gallons of liquid component, more preferably at a rate of about 1.0CFM per 1,000 gallons of liquid component.
In certain embodiments, pure oxygen or oxygen-enriched air is delivered to the bioreactor using a plurality of spargers as described above. For example, pure oxygen or oxygen-enriched air may be injected into the substantially liquid component during the ATAB using one or more 2 micron sintered stainless steel spargers. Maintaining the substantial liquid fraction under aerobic conditions will culture and enrich for aerobic mesophilic and thermophilic bacteria. In particular embodiments, the initial breakdown of organic matter in the liquid component is by mesophilic organisms, which rapidly breakdown soluble and readily degradable compounds. The heat generated by the mesophilic organisms causes a rapid increase in temperature during the ATAB, thereby enriching thermophilic organisms, which accelerate the breakdown of proteins, fats and complex carbohydrates (e.g. cellulose and hemicellulose). As the supply of these energetic compounds becomes depleted, the temperature of the liquid component gradually decreases, again promoting mesophilic organisms, causing a final "conditioning" or maturation period of the remaining organic matter in the liquid component. Thus, replacing the atmospheric oxygen supply with a pure oxygen or oxygen-enriched supply substantially reduces the amount of foam generated in the bioreactor during ATAB. The reduction in foam in turn allows for a more efficient air supply, more consistent bioreactor operation and a more robust aerobic environment, resulting in a substantial reduction of undecomposed organic matter and a more stable and cost-effective end product.
The ATAB conditions described herein allow the growth and enrichment of several thermophilic and mesophilic microorganisms used as PGPR. Useful thermophilic and mesophilic microorganisms that may be isolated from the substantive liquid component include, but are not limited to, Bacillus species (Bacillus sp.) (e.g., Bacillus israeli (B.isronensis) strain B3W22, Bacillus puppet (B.kokeshiformis), Bacillus licheniformis (B.licheniformis) strain DSM 13, Bacillus paracasei (B.paracaseformis) strain KJ-16), Corynebacterium species (Corynebacterium sp.) (e.g., Corynebacterium valium (C.effiicins) strain YS-314), marine species (Idioina sp.) (e.g., marine (I.indigo) strain SW104), Bacillus acidosis (Oceanicus sp.) (e.g., Bacillus sp.) (S.israea) strain 3523), Bacillus benthica strain (Solidaginea) such as Bacillus sp. (S.23), Bacillus sp.) (Bacillus sp.) strains, Sporosarcina sp (e.g., Sporosarcina sp. koreani (S.korosensis) strain F73, Sporosarcina luteum (S.luteola) strain NBRC105378, Sporosarcina neoformans (S.newyorkensis) strain 6062, Sporosarcina thermotolerans (S.thermophilorans) strain CCUG 53480) and Bacillus ureafaciens (U.thermophilus sp.) (e.g., Bacillus sphaericus thermophilus (U.thermophilus)).
In certain embodiments, the pure oxygen or oxygen-enriched supply disclosed herein reduces foam production in the bioreactor during ATAB by at least about 25% compared to a bioreactor utilizing an atmospheric oxygen supply during ATAB. In other embodiments, the production of foam is reduced by at least about 50%. In more preferred embodiments, the production of foam is reduced by at least about 75% or more, such as about 75%, 76%, 77%, 78%, 79%, 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95% or more. In certain embodiments, the foam level in the bioreactor is less than about 2 feet. In more preferred embodiments, the level of gas bubbles in the bioreactor is less than about 1 foot, for example 12in., 11in, 10in, 9in, 8in, 7in, 6in, 5in, 4in, 3in, 2in, 1in, 0.5in or less. For example, in an exemplary embodiment, the foam level is about 6 inches.
In one instance, a well-configured oxygen supply system should maintain a dissolved oxygen level between about 1mg/L and about 8mg/L, such as about 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3, 3.1, 3.2, 3.3, 3.4, 3.5, 3.6, 3.7, 3.8, 3.9, 4, 4.1, 4.2, 4.3, 4.4, 4.5, 4.6, 4.7, 4.8, 4.9, 5.0, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 6, 6.7, 6.6, 6, 6.7, 6.6, 7.6, 6.7, 6, 7.6, 7, 7.0, 7, 7.6, 7, 6, 7, 7.6, 7, 7.0, 7.6, or 7.6.6.6.7.6, 7.6. In a preferred embodiment, the oxygen supply system should maintain a dissolved oxygen level of between about 2mg/L and about 6mg/L, more preferably between about 3mg/L and about 4 mg/L. In certain embodiments, oxygenation of the biological reaction is measured in terms of oxidation-reduction potential (ORP). Typically, the ORP for the biological reaction is maintained between about-580 mV to about +10 mV. More particularly, it is maintained in the range between-250 mV and-50 mV.
To monitor the temperature, pH and oxygenation parameters of the ATAB, the bioreactor may be equipped with an automatic controller to control these parameters. In certain embodiments, the bioreactor is equipped with a Programmable Logic Controller (PLC) that effectively controls pH, ORP, and other parameters by adjusting the oxygen air supply to the bioreactor and the feed rate of the pH adjuster. Indeed, the delivery of oxygen to any of the method steps disclosed herein can be controlled in this manner using a PLC.
Off-gas from the slurry preparation tank and slurry storage tank contains carbon dioxide, air, ammonia and water vapour; while the off-gas from the bioreactor contains oxygen-depleted air, carbon dioxide and water vapor. In certain embodiments, these off-gases are directed to a biofilter. When applied to air filtration and purification, biofilters use microorganisms to remove unwanted elements. The off-gas flows through the packed bed and contaminants are transferred to the thin biofilm on the surface of the packing material. Microorganisms, including bacteria and fungi, are immobilized in the biofilm and degrade the contaminants.
The product stream from the bioreactor is directed to a receiving vessel and may be used as an end product or subjected to further processing at this stage. Such compositions are sometimes referred to herein as "base compositions" or "base products. In certain embodiments, the receiving vessel for the base composition is equipped with an agitation system that maintains the colloidal components of the liquid stream in a homogeneous suspension.
The initial heating step and the heat and other conditions applied in the ATAB are effective to substantially or completely eliminate human pathogenic organisms as well as weeds and seeds, leaving beneficial aerobic thermophilic and mesophilic bacteria. In certain embodiments, however, the base composition is subjected to a second heat treatment for the purpose of further reducing the microbial load so that the composition can be supplemented with exogenous microorganisms as needed, for example in a customized product. This step, referred to herein as "pasteurization" or "rapid pasteurization", depending on the time and temperature of the treatment, includes heating the liquid composition to a temperature between about 65 ℃ and about 100 ℃ for a time between about 5 minutes and about 60 minutes. In certain embodiments, the base composition is heated to at least 70 ℃, or at least 75 ℃, or at least 80 ℃, or at least 85 ℃, or at least 90 ℃, or at least 95 ℃. In certain embodiments, the base composition is heated for at least 10 minutes, or at least 15 minutes, or at least 20 minutes, or at least 25 minutes, or at least 30 minutes, or at least 35 minutes, or at least 40 minutes, or at least 45 minutes, or at least 50 minutes, or at least 55 minutes, noting that the heating time is generally inversely proportional to the heating temperature. In certain embodiments, the composition is heated to about 95 ℃ for about 30 to 45 minutes.
The liquid composition may also be subjected to one or more filtration steps to remove suspended solids. The solids left over by this filtration process can be returned to the manufacturing process system, for example to an aerobic bioreactor.
Filtration may involve a variety of different filtration sizes. In certain embodiments, the filtration size is 100 mesh (149 microns) or less. More particularly, the filtration size is 120 mesh (125 microns) or less, or 140 mesh (105 microns) or less, or 170 mesh (88 microns) or less, or 200 mesh (74 microns) or less, or 230 mesh (63 microns) or less, or 270 mesh (53 microns) or less, or 325 mesh (44 microns) or less, or 400 mesh (37 microns) or less. In particular embodiments, the filtration size is 170 mesh (88 microns), or 200 mesh (74 microns), or 230 mesh (63 microns), or 270 mesh (53 microns). In certain embodiments, a combination of filtration steps may be used, such as 170 mesh followed by 200 mesh, or 200 mesh followed by 270 mesh filtration.
Filtration is typically performed using a vibrating screen, such as a stainless steel mesh screen, a drum screen, a disk centrifuge, a pressure filtration vessel, a belt press, or a combination thereof. Filtration is typically performed on the product cooled to ambient air temperature, i.e., below about 28-30 ℃.
The base product may also be further formulated to produce a product for a specific purpose, which is sometimes referred to herein as a "formula," "formulation composition," or the like. In certain embodiments, the additive includes macronutrients such as nitrogen and potassium. Products formulated by the addition of macro-nutrients such as nitrogen and potassium are sometimes referred to as "formulated to grade," as will be appreciated by those skilled in the art. In an exemplary embodiment comprising a liquid nutritional composition prepared from chicken manure, the base composition is formulated to contain about 1.5% to about 3% nitrogen and about 1% potassium to produce a biofertilizer product suitable for use in the organic or conventional agricultural industries. For routine agricultural use only, exemplary embodiments may include formulating the base composition to contain about 7% nitrogen, about 22% phosphorus, and about 5% zinc for use as a base fertilizer to optimize plant growth and development.
In other embodiments, the additive includes one or more micronutrients as needed or desired. Although the base composition already contains a wide range of micronutrients and other beneficial substances, as described in detail below, it is sometimes beneficial to formulate the composition with such additives. Additives suitable for use in both organic and conventional agriculture include, but are not limited to, blood meal, seed meal (e.g., soybean isolate), bone meal, feather meal, humus (humic acid, fulvic acid, humins), microbial inoculants, sugars, micronized rock phosphate, and magnesium sulfate, to name a few. For conventional agriculture only, suitable additives may also include, but are not limited to, urea, ammonium nitrate, UAN-urea and ammonium nitrate, ammonium polyphosphate, ammonium sulfate, and microbial inoculants. Other materials suitable for addition to the base product will be apparent to those skilled in the art.
In certain embodiments, the material added to the base composition is approved for use in conventional agriculture only. In other embodiments, the material added to the base composition is itself approved for use in organic agricultural projects such as USDA NOP, and thus may be used in conventional, organic or regenerative agricultural projects. In a particular embodiment, the nitrogen is added in the form of sodium nitrate, in particular sodium chilium nitrate approved for organic agricultural projects. In other embodiments, potassium is added as potassium sulfate. In yet other embodiments, potassium is added as potassium chloride, potassium magnesium sulfate, and/or potassium nitrate.
The base composition may be formulated at any time after it exits the bioreactor and before it is packaged. In one embodiment, the product is formulated with macronutrients prior to any subsequent processing steps. In this embodiment, the product stream is directed to a formula receiving vessel where the macronutrients are added. Other materials may be added at this point if desired. The formulation receiver may be equipped with an agitation system to ensure that the formulation maintains suitable homogeneity.
It is obvious to the skilled worker that the subsequent process steps described above, i.e. pasteurization, filtration and formulation, can be carried out individually or in combination and in any order. Thus, for example, one embodiment includes a dispense to grade, pasteurization, two level filtration, and a second dispense step. Another embodiment does not include pasteurization and one or both levels of filtration. Other combinations are also suitable depending on the desired properties of the final composition.
It may be beneficial to adjust the final pH of the liquid composition to enhance stability prior to packaging and/or storage. Thus, in certain embodiments, the end product may be adjusted to a pH of between about 4 and about 8, or between about 4.5 and about 8, or between about 5 and about 8, or between about 5.5 and about 7.5, or between about 6 and about 7.5, or between about 5.5 and about 7.0, or between about 6.5 and about 7.0, using a suitable pH adjusting agent as described above. In a particular embodiment, the pH adjusting agent is an organic acid such as citric acid.
In certain embodiments, post-ATAB processing includes one or more of the following steps. For organic agriculture, the base composition may be formulated to a grade of 1.5-0-3 or 3-0-3(N-P-K) by the addition of sodium nitrate and potassium sulfate. Alternatively, for conventional agriculture, the base composition may be formulated to a grade of 0-0-6-2S (N-P-K) by the addition of potassium sulfate. The composition was then adjusted to a pH of 5.5 with citric acid and then rinsed through the shaker at a rate of about 40 gallons per minute. The vibrating screen is provided with a stainless steel screen mesh of 200 meshes. The filtered product is then pumped through a cartridge filter. Typical operating parameters of the cartridge filter include one or more of: (1) a pressure differential of up to 40 PSI; (2) an inlet temperature of 29.5 ℃ (85 ° f) or less; and (3) a vessel shell pressure of up to 40 PSI. In certain embodiments, the composition is subjected to a filtration step. In other embodiments, more than one filtration step is included in the method.
In certain embodiments, the liquid composition or formula is directed to a storage tank, which may be equipped with a pH and temperature control and/or agitation system. In a particular embodiment, the storage tank may also be equipped with an oxygen supply system. In such embodiments, the liquid product after ATAB is maintained under aerobic conditions by injecting pure oxygen or oxygen-enriched air at a rate of about 0.1CFM to about 3CFM per 10,000 gallons of liquid, e.g., 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, or 3.0CFM per 10,000 gallons of liquid. Preferably, the pure oxygen or oxygen-enriched air is delivered to the post-ATAB liquid product at a rate of from about 0.25CFM to about 1.5CFM per 10,000 gallons of liquid, more preferably about 0.5CFM per 10,000 gallons of liquid. In certain embodiments, the oxygen is delivered by a plurality of spargers, such as the spargers described above. By maintaining the post-ATAB liquid product (i.e., the liquid composition or formulation) under aerobic conditions, the formation of anaerobic compounds is avoided.
Packaging of the final product may include dispensing the product into a container from which the material may be poured. In certain embodiments, the filled container may be sealed with a membrane lid ("vent lid", e.g., from w.l. gore, Elkton, MD) to allow air to circulate in the headspace of the container. These films may be hydrophobic and have sufficiently small perforations that the material does not leak even when the container is fully inverted. In addition, the perforations may be suitably small (e.g., 0.2 microns) to eliminate the risk of microbial contamination of the container contents.
Detailed Description
In order to describe the present invention in more detail, the following examples are provided. They are intended to illustrate rather than to limit the invention.
Example 1 Process for producing a Fertilizer/nutritional composition from chicken manure
An embodiment of the production process described herein for producing liquid and solid compositions from chicken manure is depicted in fig. 1. The production process depicted in fig. 1 results in a pathogen-free product that retains the macro and medium nutrients and micronutrients present in layer chicken manure. In addition, the process described herein removes potentially problematic phosphorus and hydrogen sulfide from the product.
As shown in fig. 1, the process begins at 10 when raw chicken manure is transported in a covered, drop-bottom trailer directly from a farm to the site. The truck is unloaded at the site into a mixing tank and mixed with citric acid 15 and water to form a homogeneous slurry. Citric acid binds the natural organic ammonia in the original feces.
The next step in the process involves the preparation of the feed material 20. In this step, the stored slurry is mixed with sufficient water 25 to raise the moisture level of the slurry to a moisture range of about 84% to about 87% moisture. The mixing tank was fitted with a 2 micron sintered stainless steel sparger for delivering pure oxygen. During mixing, pure oxygen 22(> 96%) was injected into the slurry at a rate of 0.5CFM per 10,000 gallons of slurry. The slurry is then heated to 65 ℃ with steam 30 for at least 1 hour to break down the feces into fine particles and to homogenize well into a slurry for further processing. In addition, the steps include killing any pathogens present in the original stool that are potentially harmful to humans and/or plants and activating both indigenous mesophilic and thermophilic bacteria. In a particular embodiment, this part of the manufacturing process is separated from the rest of the system to reduce the risk of contamination of the processed fertilizer material with the original manure. The mix tank processing parameters for the feed material 20 preparation are shown in table 3.
TABLE 3 blending tank processing parameters
HZ, Hertz; HP, horsepower; CPS, centipoise; PSI, pounds per square inch; CFM, cubic feet per minute
The slurry is then sent to a centrifuge 35, while the debris, oyster shells and other grits from the chicken feed are removed 40. In a preferred embodiment, centrifuge 35 is a decanter centrifuge. Centrifuge parameters suitable for separating the solid and liquid fractions are shown in table 4. The centrifuge 35 separates the slurry into two streams, a liquid stream and a solids stream. The solids stream 43 is dried to about 12% (or less) moisture and used to produce a dry fertilizer product ("dry formulation"). Liquid stream 45 is sent to aerobic bioreactor 50. In another embodiment, the slurry is first sent to centrifuge 35 and then to a vibratory separator (SWECO, Florence, KY, USA) in a two-step separation process.
TABLE 4 centrifuge parameters
RPM, revolutions per minute
After liquid stream 45 is fed to aerobic bioreactor 50, indigenous microorganisms are cultured. During the incubation, pure oxygen 51(> 96%) was injected into the liquid stream at a rate of 1.0CFM/1,000 gallons. The microorganisms metabolize the organic components of the feed into primary and secondary metabolic byproducts including, but not limited to, plant growth factors, lipids and fatty acids, phenols, carboxylic/organic acids, nucleosides, amines, sugars, polyols, and sugar alcohols, among other compounds. Depending on the degree of aging, the liquid feed is left in aerobic bioreactor 50 under mild agitation (e.g., 6 complete turns per hour) for a minimum of 1 day to a maximum of about 8 days, and a uniform minimum temperature of 55 ℃. Injection of pure oxygen instead of atmospheric or ambient oxygen results in a foam level of less than 6 inches. The aerobic bioreactor process parameters are provided in table 5.
TABLE 5 bioreactor Process parameters
CFM, cubic feet per minute; GPH, gallons per hour; PSI, pounds per square inch; hz, Hertz; ORP, oxidation reduction potential; PLC, programmable logic controller
The liquid product from aerobic bioreactor 50 is managed in either of two ways. The first is a standard production process and the second is a special production process. Both products are formulated 52 (initial formulation) with supplemental nitrogen (e.g., sodium nitrate, blood meal or hydrolyzed rapeseed) and potassium (e.g., potassium sulfate) and filtered directly into a storage tank or package 70. For the standard product process 62, the formulated liquid product is filtered 63 and transferred to a storage tank 70. The formula standard product is stored under mild aerobic conditions and at a temperature in the range of about 45 ℃ (i.e., the temperature at which the product enters a mesophilic state) to about 15-20 ℃ (i.e., room temperature). For a particular product, the formulated liquid product is flash pasteurized 55, filtered 60 through one or two filtration steps, and then further formulated (secondary formulation) 65 for a particular use, such as with a custom microorganism. The specialty product is then transferred to a storage tank or package 70. During storage 70, pure oxygen 72(> 96%) was injected into the formulation liquid product or secondary formulation at a rate of 0.5CFM/10,000 gallons.
The liquid product was filtered through a vibrating stainless steel screen and then through a cartridge filter vessel set-up with operating parameters including 27 Gallons Per Minute (GPM) inlet flow rate, 84 pounds Per Square Inch (PSI), 0 differential pressure, and 27 ℃. In such embodiments, the cartridge filter is rated for 100 mesh with an absolute rating of 99.9%. For the particular embodiment depicted in fig. 1, the formulated liquid product (either the standard product or the specialty product after pasteurization step 55) is fully homogenized with the necessary modifications and then cooled to ambient temperature (i.e., about 15-20 ℃). For example, the improvement includes sodium nitrate and potassium sulfate. The pH of the homogenized product was titrated to 5.50 with citric acid and then flushed through a vibrating stainless steel mesh screen at a rate of about 40 gallons per minute. The vibrating screen is provided with a stainless steel screen mesh of 200 meshes. The filtered product is then pumped through a cartridge filter to a receiving vessel or 6,500 gallon storage tank having a loading of about 275 gallons. The operational parameters of the cartridge container include a pressure differential of up to about 40 pounds Per Square Inch (PSI), an inlet temperature of up to about 85 ° f (about 29.5 ℃) and a container shell pressure of up to about 40 PSI. The parameters for pasteurization 55 and filtration 63, 60 are summarized in table 6.
TABLE 6 downstream processing after the bioreactor
For storage 70, the storage vessel is maintained under mild aerobic conditions and a pH of about 6.5 to about 7.0. The headspace of the storage tank was purged with sterile air and stirred to ensure adequate mixing of the air. Although the product is stable indefinitely under these conditions, the storage also serves as a maturation stage in which mesophilic bacteria convert the ligands and cellulosic material into compounds useful to the plant. A third filtration step is applied prior to bulk transport or packaging 70. The bottle was sealed with a film lid to allow air to circulate in the headspace of the container. The membrane is hydrophobic with very small (less than about 2 microns) size perforations so that the material does not leak even when the container is fully inverted. The small size of the perforations also significantly reduces the likelihood of microbial contamination from the environment. Storage parameters for some cases of storage and filtration are shown in table 7.
TABLE 7 storage parameters
HP, horsepower; RPM, revolutions per minute; QC, quality control
In certain embodiments, quality control measures are included to reduce the risk of pathogen re-emergence. For example, the above fertilizer production method is a closed system to prevent accidental contamination by the original manure. In this case, quality control comprises three main quality assurance steps: 1) storing the original feces in a closed canister, remote from the remainder of the manufacturing process; 2) transporting the product from the formulation/rapid pasteurization step directly to storage without exposure; 3) the bulk package (carrier bag/can) and bottles are placed in an area remote from the fecal storage.
Example 2 bioreactor kinetics during ATAB
The rate of organic matter decomposition during ATAB is adversely affected by the increase in foaming in the bioreactor, which interferes with oxygen supply. Insufficient oxygen supply of the liquid stream during ATAB in turn makes less available oxygen and reduces the efficiency of organic matter decomposition. The oxidation-reduction potential (ORP) can be used to measure the efficiency of oxygen delivery, which results in increased oxidation of compounds in the liquid stream and a decrease in ORP values. Thus, ORP can be used to measure organic matter decomposition kinetics in a bioreactor.
To compare the ATAB kinetics of pure oxygen versus atmospheric oxygen, a bioreactor using pure oxygen delivery was compared to a bioreactor of, for example, ambient air. The splitting of the ATAB was performed 5 times for 80-90 hours in a bioreactor equipped with a 2 micron sintered stainless steel sparger injecting pure oxygen into the liquid stream at a rate of 1.0CFM/1,000 gallons (see 3A-3E). For comparison, a split ATAB of 80-90 hours was performed 5 times in a bioreactor equipped with a jet aerator supplying ambient air to the liquid stream (see fig. 2A-2E). As shown in fig. 2A-E and 3A-E, the average reaction rate over time in a bioreactor delivering ambient air is significantly lower compared to a bioreactor delivering pure oxygen. Thus, delivery using pure oxygen achieves an increase in the rate of organic matter decomposition compared to ambient air.
In another experiment, three separate runs in a bioreactor with pure oxygen delivery were compared to three runs in a bioreactor supplied with ambient air. For this study, all feed feces were sourced from the same site. First, the feed material is homogenized with water (i.e., vigorously mixed and soaked) to increase the moisture to a level between about 87% and 88%, and the temperature is raised to at least 65 ℃ for a minimum of 1 hour using direct water vapor injection. Citric acid was added to the resulting slurry to lower the pH to 6.5.
In the next step, the slurry is separated in a decantation centrifuge. The centrifugation conditions were consistent in each batch and yielded comparable centrates. The decanter centrifuge is operated at an input speed of 20-25GPM and produces a centrate having a moisture content of between 94% and 96% and a pH of between 6.5 and 6.7.
The centrate is then processed in an aerobic bioreactor using a turnover rate of 15-17x per hour and controlling the pH between 6.9 and 7.0. In ambient air operation, between 24 and 36CFM of ambient air is supplied to the bioreactor. For oxygen-rich operation, the bioreactor is supplied with between about 3 to 6CFM of pure gaseous oxygen. For all 6 runs, a similar liquid volume between about 12,500 and about 13,000 gallons of liquid was used in the bioreactor. The minimum residence time in the bioreactor is 72 hours at 55 ℃.
The results are summarized in fig. 4. All three oxygen-enriched runs achieved higher bioreactor temperatures than the ambient air supplied run.
Example 3 foam production of bioreactor during ATAB
The foam levels produced during ATAB in a bioreactor utilizing atmospheric oxygen delivery were compared to the foam levels produced in a bioreactor using the pure oxygen or oxygen-enriched delivery system disclosed herein. The liquid fertilizer production process was performed for two different bioreactor oxygen delivery systems. In process a, the production process was carried out as described in example 1. Two bioreactors were used in sequence to facilitate the ATAB. Each bioreactor in process a was equipped with a 2 micron sintered stainless steel sparger that injected pure oxygen into the liquid stream at a rate of 1.0CFM/1,000 gallons. In process B, each of the bioreactors is equipped with a sparge aeration device to supply ambient air to the liquid stream. As shown in table 8, the delivery of pure oxygen significantly reduced the foam level in the bioreactor compared to ambient air delivery.
TABLE 8 bioreactor foam level
Example 4 identification of thermophilic and mesophilic bacteria in liquid streams during ATAB
The identity of the thermophiles and mesophiles present in the liquid stream during the ATAB period is determined by sampling the liquid stream material in the bioreactor under peak growth conditions. The samples were serially diluted with tryptic soy medium and 750uL of each diluted sample was dispensed into sterile petri dishes onto which 20mL of melted tryptic soy agar was poured. The petri dishes were each incubated at ambient temperature or 55 ℃ for 18 hours. Colonies were picked directly from petri dishes. For each colony, 16S rRNA was extracted and sequenced according to standard techniques in the art. Microorganisms were identified by performing a BLAST search on the sequencing date. The results are summarized in table 9.
The present invention is not limited to the embodiments described and illustrated herein. It can be changed and modified within the scope of the claims.
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