ORGANIC NITROGENOUS FERTILIZERS

Abstract

The present invention relates to organic nitrogen fertilizers and methods for producing organic nitrogen fertilizers, including retrieving high concentration organic ammonia from discarded organic material.

Claims

1. (canceled)

2. (canceled)

3. (canceled)

4. (canceled)

5. (canceled)

5. (canceled)

7. (canceled)

8. (canceled)

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9. (canceled)

11. (canceled)

12. A method of producing organic ammonia, comprising: a. heating an organic waste material in an anaerobic digester device to drive a biological anaerobic digestion of the organic waste material and yield a digested organic waste composition; b. separating solid portions of the organic waste composition from an effluent of the digested organic waste composition; c. heating said effluent to evolve CO.sub.2-laden gas from the effluent; d. transferring the heated effluent to a steam stripping apparatus to extract NH.sub.3 from said heated effluent in a steam/NH.sub.3 solution; and e. condensing the steam/NH.sub.3 solution to yield an aqueous NH.sub.3 product derived from effluent without chemical reactions.

13. The method of claim 12, wherein said step of heating said effluent drives the chemical equilibrium of ammonium bicarbonate toward the production of NH.sub.3 and CO.sub.2.

14. The method of claim 12, further comprising adding a basic chemical agent to the effluent before or during the step of heating said effluent to increase the pH of the effluent.

12. The method of claim 12, further comprising the step of transferring the CO.sub.2-laden gas to a packed column to cool the CO.sub.2-laden gas and dissolve NH.sub.3 present in the gas in a cooling fluid.

16. The method of claim 15, further comprising transferring the cooling fluid and NH.sub.3 dissolved therein to the steam stripping process to extract the dissolved NH.sub.3.

17. A liquid organic nitrogenous fertilizer composition, comprising: a. an aqueous solution of i. the aqueous NH.sub.3 product of any of claims 12-16; and ii. an organic acid in a concentration of about 6% to about 50%.

18. (canceled)

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24. The composition of claim 17, wherein the concentration of organically produced ammonia is in a concentration of about 10% w/w to about 20% w/w.

25. (canceled)

25. (canceled)

27. (canceled)

28. A method of producing organic ammonia, comprising: a. heating a nitrogen-rich effluent to evolve CO.sub.2-laden gas from the effluent; b. transferring the heated effluent to a steam stripping process to extract NH.sub.3 from said heated effluent in a steam/NH.sub.3 solution; and c. condensing the steam/NH.sub.3 solution to yield an aqueous NH.sub.3 product derived from said effluent without utilizing chemical reactions.

29. The method of claim 28, wherein said step of heating said effluent drives the chemical equilibrium of ammonium bicarbonate toward the production of NH.sub.3 and CO.sub.2.

30. The method of claim 28, further comprising adding a basic chemical agent to the effluent before or during the step of heating said effluent to increase the pH of the effluent.

31. The method of claim 28, further comprising the step of transferring the CO.sub.2-laden gas to a packed column to cool the CO.sub.2-laden gas and dissolve NH.sub.3 present in the gas in a cooling fluid.

32. The method of claim 31, further comprising transferring the cooling fluid and NH.sub.3 dissolved therein to the steam stripping process to extract the dissolved NH.sub.3.

33. A liquid organic nitrogenous fertilizer composition, comprising: a. an aqueous solution of i. the aqueous NH.sub.3 product of any of claims 28-32; and ii. an organic acid in a concentration of about 6% to about 50%.

34. (canceled)

35. (canceled)

36. The composition of claim 33, wherein the concentration of organically produced ammonia is in a concentration of about 10% w/w to about 20% % w/w.

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44. A liquid organic nitrogenous fertilizer composition, comprising: an aqueous solution including a biologically produced ammonia in a concentration of about 3% to about 25%.

45. The composition of claim 44, further comprising humic acids as a chelation agent for the ammonia.

44. The composition of claim 44, wherein said humic acids is present in a concentration of about 3% to about 8%.

47. The composition of claim 45, wherein the concentration of organically produced ammonia is in a concentration of about 10% w/w to about 20% w/w.

48. The composition of claim 44, further comprising an organic acid.

49. The composition of claim 48, wherein said organic acid is a triprotic acid.

50. (canceled)

51. (canceled)

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] FIG. 1 shows a flow chart of a process for processing ammonia-laden biodigestion effluent.

[0035] FIG. 2 shows an apparatus for processing biodigestion effluent to produce an organically compliant ammonia-rich aqueous fluid.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

[0036] Reference will now be made in detail to certain embodiments of the invention, examples of which are illustrated in the accompanying drawings. While the invention will be described in reference to these embodiments, it will be understood that they are not intended to limit the invention. Conversely, the invention is intended to cover alternatives, modifications, and equivalents that are included within the scope of the invention as defined by the claims. In the following disclosure, specific details are given as a way to provide a thorough understanding of the invention. However, it will be apparent to one skilled in the art that the present invention may be practiced without these specific details.

[0037] Referring to the drawings, wherein like reference characters designate like or corresponding parts throughout the several views, and referring particularly to FIGS. 1-2, it is seen that the present invention includes various embodiments of organic fertilizers containing organically produced ammonia, and methods of production of such fertilizers.

[0038] Methods of Producing Organic Ammonia Fertilizers

[0039] As seen in FIG. 1, the present invention may include a process for extracting a nitrogen rich effluent from an unrefined waste, or discarded organic material, source such as manure, food waste, municipal sewage, or other sources of natural nitrogenous material. FIG. 1 provides a generalized visual overview of the effluent processing steps. The discarded organic material may be introduced into a first mixing tank 101, which may be a large basin or vat able to receive large volumes of organic material. For example, the tank 101 may hold a volume of organic material in a range of about 5,000 gallons to about 500,000 gallons. The tank 101 may have an agitation mechanism for mixing the organic material and any additional additives into a substantially uniform, but heterogeneous mixture to avoid stratification of the mixture. For example, the mixing tank may include a central vertical agitator, a stirring rod, water injectors, recirculation pumps, or other agitation mechanism.

[0040] The additives for improving the anaerobic digestion and nitrogen content of the resulting digested mixture may be added into the mixing tank 101. Such additives may include blood meal, sweet clover, and other nutrients such as sodium, calcium, magnesium. Trace amounts of elements such as nickel, cobalt, molybdenum, and selenium, which may acts as cofactors of anaerobic metabolic enzymes may be added as well.

[0041] After the effluent has been sufficiently mixed with the additives, the effluent mixture may be transferred to an anaerobic digester 102 in which anaerobic bacteria break down nitrogenous compounds to form natural, organic ammonia and nitrates. The anaerobic digester may be a closed vessel, from which oxygen is substantially removed. The anaerobic digester 102 may be a sealed anaerobic lagoon digester, a plug flow digester (a long, narrow concrete tank); complete mix digester (an enclosed, heated tank with a mechanical, hydraulic, or gas mixing system); a dry digestion digester (an upright, silo-style digester made of concrete and steel), or other type of anaerobic digester. In the anaerobic digester, anaerobes hydrolyze the complex organic material (e.g., carbohydrates and polypeptides) in the effluent mixture under anaerobic conditions, resulting in simpler organic molecules (e.g., the sugars and amino acids). Additional bacteria (e.g., acidogenic bacteria) may then catabolize the simpler organic molecules to form carbon dioxide, hydrogen, ammonia, and organic acids. Acetogenic bacteria may convert the organic acids into acetic acid, along with additional ammonia, hydrogen, and carbon dioxide. In some embodiments, methanogens may be present to convert these products to methane and carbon dioxide.

[0042] The mixing tank 101 and the anaerobic digester 102 may be connected via pipeline, allowing the effluent mixture to flow by pump or gravity from mixing tank 101 to the digester 102. Once the waste water mixture is delivered into the anaerobic digester 102, it may be agitated by an agitation mechanism such as a central vertical agitator, a stirring rod, water jets or effluent recirculation to create circulation, or other agitation mechanism. The effluent mixture is continuously stirred during the digestion period, which may be in the range of about 1 to about 30 days while maintained at a temperature in a range of about 70 F. and about 115 F. (e.g., about 80 F. to about 105 F., or any value or range of values therein). This temperature range is ideal for the anaerobic bacteria present in the digester and maximizes the metabolic activity thereof. Biogas, including methane and carbon dioxide, and nitrogenous compounds, including ammonia and nitrates are produced and dissolved in the digested effluent product.

[0043] After the digestion period, the biogas produced during the may be siphoned off of the digested mixture and collected in a biogas separator 103. The biogas may be subsequently processed through a methane capture process 104, which may include a scrubbing process to remove contaminating gases such as CO.sub.2 and H.sub.2S. The biogas separator may simply include the periodic or continuous application of a partial vacuum to the digester 102 to remove the gas produced by the digesting process. In other examples, the digested effluent and biogas may be transported to a separator chamber, such as a cyclonic chamber or centrifuge to separate the phases of the digested material into solids, liquids, and biogas. The biogas may be removed by vacuum, and the effluent may then be collected and transported to a liquid/solid separator 105.

[0044] The liquid/solid separator 106 allows the ammonia and nitrate rich liquid effluent from the digester to be isolated for further processing. The liquid/solid separator 105 may be a settling tank that allows the solid to settle to the bottom and yielding a separate liquid fraction that can be removed from the top by a pump through a filtered outlet. In other examples, the liquid/solid separator 105 may be a screw press that captures the solids in the effluent and allows the liquid phase to be separately captured. In still other examples, the liquid/solid separator 105 may be a dewatering centrifuge, able to separate and collect the liquid phase of the biodigester effluent. The liquid phase may be then transferred to a collector 107 for an organic ammonia capture process. The solid portion of the effluent may be used in a separate drying and stabilization processing 106 to produce a solid nitrogen fertilizer.

[0045] The liquid phase may be transferred from the collector 107 to a column separation apparatus 200 to purify and capture the ammonia from the liquid phase. The apparatus 200 is shown in FIG. 2, and includes several components. The liquid phase may first be transferred to a heating chamber 201 in which the liquid phase effluent may be heated to a temperature in a range of about 120 F. to about 150 F. to drive CO.sub.2 out of the liquid phase effluent. The heating process may remove up to about 90% of the CO.sub.2 from the liquid phase, thereby pushing the chemical equilibrium of ammonium bicarbonate and ammonia significantly toward free ammonia, thereby facilitating an extraction of a greater quantity of ammonia from the liquid phase in subsequent steps. Ammonia largely remains in the liquid phase as bound ammonium compounds and ammonia. However, there may be a significant amount NH.sub.3 gas evolved from the effluent.

[0046] The ammonium-rich liquid phase effluent 201c may then be transferred to a packed column 207 by a conduit 201a. The evolved gas from the heating chamber 201 may be transferred via conduit 201b to a separate interim packed column 202 that may be designed to recapture the NH.sub.3 gas in the evolved gas and thereby recapture the desired NH.sub.3 and separate and dispose of the CO.sub.2 gas. The packed column 202 may contain a conventional, high surface area packing material 202a as a stationary phase. The packed material may be a corrosion-resistant, high surface area arrangement of metal or plastic grates or other high surface area structures to thoroughly mix the liquid and gases present in the column. A cooling fluid (e.g., water) from a fluid source 206 may be provided in the upper portion of the column 202 (e.g., by spraying through a spraying bar) in order to lower the temperature of the evolved gas such that the NH.sub.3 vapor is condensed and dissolved in the aqueous effluent phase, while all or nearly all of the CO.sub.2 remains as gas. The cooling fluid may lower the temperature within the column to about 100 F. or less (e.g., in a range of about 60 F. to about 100 F., or more particularly in a range of about 70 F. to about 90 F.), allowing a large majority of the ammonia to be dissolved in water or aqueous fluid in the column 202. The lower the pH and temperature, the more ammonia can be reabsorbed (dissolved) in an aqueous fluid. For example, at a pH of 8.5 or less and a temperature of about 85 F. or less, more than 75% of ammonia in a closed system is in the dissolved, ionized ammonium NH.sub.4.sup. form.

[0047] The evolved gas may be transferred directly into the packed material 202 by conduit 201b in order to facilitate mixing and high surface area interaction of the evolved gas and the cooling fluid. The CO.sub.2 gas may rise and escape through a conduit in the upper section 202a to a CO.sub.2 exhaust and scrubbing system 205. A partial vacuum may be applied to the conduit 205a to assist in removing the CO.sub.2 gas. The NH.sub.3 vapor is largely recaptured in the cooling fluid and collected in solution 203 at the bottom of the column 202.

[0048] The solution 203 can then be transferred to the packed column 207 by conduit 204. The conduit 204 delivers the solution 203 to the upper portion of the column 207 above packed material 207a positioned in the column 207. As previously mentioned, the effluent fluid 201c from the heating chamber 201 is also delivered to the upper portion of column 207 by conduit 201a. Thus, the NH.sub.3 collected from both the liquid effluent 201c and the evolved gas are combined in the packed column 207 to separate NH.sub.3 out of the liquid phase solutions 201c and 203.

[0049] As in the column 202, the packed material in the column 207 may be a corrosion-resistant, high surface area arrangement of metal or plastic grates or other high surface area structures. In order to maintain a high temperature of the liquid effluent 201c and the solution 203 as they pass through the packed material and promote the volatilization of the ammonia therein, steam may be provided to the bottom of the column 207 from a boiler 208 via line 208a. The high surface area packing material 207a may allow for high surface area interaction between the steam and the fluids 201c and 203 to allow for the collection of the volatilized ammonia. The steam/ammonia mixture may rise through the column 207 and collected by a conduit 207b that transfers the steam/ammonia mixture to a condenser 209 for cooling and collection. The steam/ammonia mixture condenses to form an aqueous ammonia solution that has a concentration in the range of 10% NH.sub.3 w/w to about 25% NH.sub.3 w/w. The concentrated aqueous ammonia solution is drained from the condenser 209 via collection conduit 209a and collected.

[0050] The liquid phase effluent 207c that remains after the steam scrubbing process runs to the bottom of the column 207 and collects in the bottom thereof. A waste conduit 210a may transfer the liquid phase effluent 207c to a waste processing unit 210. The liquid phase effluent 207c that drains from the column 207 is substantially free of ammonia, and thus has significantly reduced toxicity.

[0051] In some embodiments, the concentrated aqueous ammonia solution may be further concentrated by returning the solution to stripping column 207 to be steam stripped a second time. In such embodiments, the concentration of the double-steam-stripped aqueous ammonia may be in the range of about 15% NH.sub.3 to about 30% NH.sub.3 by weight. In still further embodiments, the concentration of ammonia in the captured aqueous ammonia solution may be increased to a concentration in a range of 25% NH.sub.3 to about 35% NH.sub.3 by weight by pressurizing the stripping column 207. The steam stripping column pressure may be increased by pumping steam into the stripping column from the boiler 208. The stripping column 207 may be pressurized to an internal pressure of about 2.5 atm to about 4 atm. In such embodiments, the pressure inside the stripping column 207 may be maintained by check valves (or other valve mechanisms) placed in the conduits 204, 207b, and 210a. The condenser may then drop the temperature of the steam/ammonia solution to a temperature of below about 55 C. (e.g., a temperature in a range of about 40 C. to about 50 C.) in order to keep the ammonia in solution at a higher concentration of 25% NH.sub.3 w/w to about 35% NH.sub.3 w/w at ambient pressure. Alternatively, the aqueous ammonia solution yielded in the condenser 209 can be maintained under higher pressure (e.g., about 2 atm to about 3 atm) and/or low temperature (e.g., about 40 C. to about 60 C.) in order to keep the ammonia in solution at higher concentration.

[0052] In still further embodiments, the ammonia solution produced by the foregoing steps may also be further concentrated by the further step of adding a basic agent (e.g., NaOH) and heating the resulting ammonium hydroxide solution and vacuuming off the evolved NH.sub.3 gas into an extremely low-temperature condenser operable to cool the liquid to at least 28 F. to capture the NH.sub.3 gas as a liquid at high concentration. Such NH.sub.3 product may have concentrations of greater than 35% w/w of ammonia up to substantially anhydrous NH.sub.3 liquid.

[0053] Organic Ammonia Fertilizers

[0054] The organic ammonia and other nitrogenous compounds produced by the foregoing methods can be included in organic fertilizers that are compliant with NOP and other agency standards for use in organic farming. The ammonia produced by the foregoing methods may be mixed with various additional organic-compliant ingredients to produce a balanced organic ammonia fertilizer.

[0055] The organic fertilizers of the present invention may be liquid fertilizers that include a concentration of organic ammonia in a range of 10% by weight to about 25% by weight. The fertilizers may further include organic acids that may serve to balance the pH effects of the concentrated ammonia in the fertilizer. The pH may be maintained in a range around neutral pH, such as between about pH 6 and pH 7 (e.g., from about pH 6.5 to about pH 7.5). To balance the pH of the liquid fertilizer, the liquid fertilizer may include one or more organic acids.

[0056] The organic fertilizers may include one or more weak organic acids or salts thereof (e.g., polyprotic organic acids or salts thereof), such as citric acid, malic acid, fumaric acid, salts of such organic acids, and combinations thereof. Other simpler organic acids, such as acetic acid salts of such organic acids may be used as well. The organic acids must be from organically-compliant sources (e.g., OMRI compliant) Citric acid may be preferred due to its tri-protic chemistry and superior buffering capabilities. The organic acid(s) may be present in a concentration in the liquid fertilizer in a range of about 15% by weight to about 50% by weight, depending on the concentration of ammonia in the liquid fertilizer. For example, the concentration of citric acid in the liquid fertilizer by weight may be about twice the amount of ammonia present in the solution by weight. In such examples, if the concentration of organic ammonia in the liquid fertilizer is 10% by weight, the concentration of citric acid may be about 20% by weight. Simpler monoprotic acids may be present in higher concentrations, due to their lower buffering capacity.

[0057] The organic fertilizers of the present invention may also include humic acid which helps with nitrogen fixation in the organic fertilizers. Liquid ammonia fertilizers suffer from nitrogen loss through the evaporation or other pathways of loss. Planting soils are typically acidic to optimize conditions for the growth of plants, which exhibit optimal germination and growth in a pH range of about pH 5.5 to about pH 7.0. The acidic pH of the soil can drive ammonia volatilization. This particularly significant where the fertilizer composition has a relatively high nitrogen concentration (e.g., greater than 10% w/w), since the higher concentration results in a higher rate of volatilization.

[0058] Humic acids are able to retain NH.sub.4 as well as aid in NH.sub.3 ammonia volatilization reduction. Humic acids have high cation exchange capacity (CEC) that allows it to retain soil cations and can significantly reduce NH.sub.3 volatilization upon addition to an acid soil (e.g., through the addition of peat). The addition of humic acids to the organic NH.sub.3 fertilizer of the present invention significantly reduces NH.sub.3 volatilization and lead to effective accumulation of NH.sub.4 in the planting soil, despite having an acidic pH (e.g., about pH 5.5 to about 7.0). The humic acids may provide the additional benefit of providing short carbon-chain molecules

[0059] Humic acids may be added included in the organic fertilizer composition of the present invention in a concentration in a range of about 3% w/w to about 8% w/w. The amount of humic acids included in the organic fertilizer may vary with the concentration of ammonia provided therein. For example, in compositions comprising about 10% to about 15% NH.sub.3 w/w, the fertilizer composition may include about 3% to about 4% w/w of humic acids. In compositions comprising about 15% to about 25% organic NH.sub.3 w/w, the fertilizer composition may include about 5% to about 8% w/w of humic acids.

[0060] The organic fertilizer composition of the present invention may also include additional components routinely used in the art, for example, humectants, adjuvants, antioxidants, stabilizers, plant macronutrients, plant micronutrients, and combinations thereof.

CONCLUSION/SUMMARY

[0061] The present invention provides organic ammonia fertilizer compositions and methods of making the same. It is to be understood that variations, modifications, and permutations of embodiments of the present invention, and uses thereof, may be made without departing from the scope of the invention. It is also to be understood that the present invention is not limited by the specific embodiments, descriptions, or illustrations or combinations of either components or steps disclosed herein. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application, to thereby enable others skilled in the art to best utilize the invention and various embodiments with various modifications as are suited to the particular use contemplated. Although reference has been made to the accompanying figures, it is to be appreciated that these figures are exemplary and are not meant to limit the scope of the invention. It is intended that the scope of the invention be defined by the claims appended hereto and their equivalents.