Methods and systems for mobility of nitrogen, carbon, and phosphorus in soil systems amended with electrochemically treated waste activated sludge

Abstract

A method and system for enhancing nutrient mobility in soil is disclosed. The method includes providing waste including one or more of waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof and preparing an alkaline electrolyte solution. The method further includes subjecting the waste to electrolysis in the alkaline electrolyte solution using a pair of electrodes positioned within a serpentine flow electrochemical cell operated at a cell potential of approximately ±2.5 volts with periodic polarity switching, thereby producing an organic mineral fertilizer formulation. The method also includes applying the organic mineral fertilizer formulation to a soil system selected from agricultural soil and potting mix at a rate of approximately 70 pounds nitrogen per acre. The organic mineral fertilizer formulation can comprises ammonium (NH₄⁺), nitrate (NO₃⁻), and phosphorus.

Description

Attorney Docket No.: 072253-92000METHODS AND SYSTEMS FOR MOBILITY OF NITROGEN, CARBON, AND PHOSPHORUS IN SOIL SYSTEMS AMENDED WITH ELECTROCHEMICALLYTREATED WASTE ACTIVATED SLUDGECROSS-REFERENCE TO RELATED PATENT APPLICATIONS

[0001] This application claims priority to U.S. Appl. Serial No. 63 / 706,482, filed October 11, 2024 entitled “Methods and Systems for Mobility of Nitrogen, Carbon, and Phosphorus in Soil Systems Amended with Electrochemically Treated Waste Activated Sludge” which patent application is commonly owned by the owner of the present invention. This patent application is incorporated herein in its entirety.TECHNICAL FIELD

[0002] The present invention relates to methods and systems for enhancing the mobility of nitrogen, carbon, and phosphorus in soil systems through the use of electrochemically treated: sludge, waste activated sludge (EWAS), biosolids, manure, and / or food waste. Specifically, the invention focuses on sustainable agricultural practices and nutrient management by utilizing electrochemical treatments to improve the release and sorption dynamics of essential nutrients in amended soils. This technology supports slow-release fertilizer formulations, carbon storage, soil health, enhanced plant growth, while contributing to reduced nutrient runoff and promoting the circular economy of nitrogen in agricultural environments.STATEMENT OF GOVERNMENT INTEREST

[0003] This invention was made with government support under NSF 20-553 Gen-4 Engineering Research Centers Award No. 2133576, awarded by the National Science Foundation, EEC Division of Engineering Education and Centers, NSF Engineering Research Center for Advancing Sustainable and Distributed Fertilizer production (CASFER). The UnitedAttorney Docket No.: 072253-92000States government has certain rights in the invention.BACKGROUND

[0004] By the year 2050, the global population is projected to reach approximately 9.7 billion people (UN, 2023), requiring a substantial increase in global food production — estimated between 35% and 56% — without accounting for the compounding effects of climate change and the continued loss of arable land (van Dijk et al., 2021).

[0005] This rapidly growing demand for food underscores a critical need for sustainable nutrient management practices that can support agricultural productivity without exacerbating environmental degradation. For decades, synthetic fertilizers have enabled large-scale agricultural production by supplying essential macronutrients such as nitrogen (N), phosphorus (P), and carbon (C). However, this success has come at a cost. The increased reliance on conventional fertilizers has contributed to significant environmental burdens, including nutrient runoff, eutrophication, greenhouse gas emissions, and soil degradation.

[0006] Traditional fertilizer components, including ammonium (NHU), urea, and phosphate- based compounds, are prone to leaching and runoff during rainfall or irrigation events. These nutrient losses often lead to the contamination of local waterways with nitrogen and phosphorus, driving harmful algal blooms and eutrophication (EPA, 2023). Eutrophic conditions can deplete dissolved oxygen, induce hypoxia, and result in large-scale fish kills, acidification, and other adverse effects on aquatic ecosystems and human health. Simultaneously, municipal wastewater treatment plants (WWTPs) worldwide generate large quantities of waste activated sludge (WAS), a nutrient-rich byproduct containing significant concentrations of organic matter, nitrogen, phosphorus, and carbon.

[0007] In the United States alone, over twelve million tons of sewage sludge are produced annually, much of which is disposed of via landfill or incineration — methods that not only incurAttorney Docket No.: 072253-92000 high operational costs but also squander valuable nutrient resources (Kroiss, 2004). It is estimated that sludge management and disposal can account for up to 50-60% of the total operational expenditures of a WWTP.

[0008] The beneficial reuse of WAS as a soil amendment has been practiced for decades due to its potential to enhance soil organic matter, microbial biomass, aggregate stability, and overall soil health index (Sharma et al., 2017; Ippolito et al., 2021). However, before land application, WAS must be treated to meet pathogen reduction and stabilization standards established by the U.S. Environmental Protection Agency (EPA). Conventional treatment methods include heat drying, composting, and alkaline stabilization. Each of these approaches has notable drawbacks. Heat treatment, while effective at pathogen destruction, can result in ammonia volatilization, the loss of nitrogen, and the concentration of heavy metals. Alkaline stabilization — commonly achieved by incorporating materials such as fly ash to elevate pH and disinfect sludge — presents a more cost-effective alternative but can still permit pathogen regrowth during storage. Composting methods, though environmentally preferable, demand extended processing times, technical oversight, and often result in nitrogen loss through volatilization (Le & Price, 2024).

[0009] These limitations highlight a broader challenge within the wastewater sector: the need for safe, economically viable, and high-nutrient-recovery sludge treatment technologies. One emerging solution is the application of alkaline electrolysis to produce electrochemically treated waste activated sludge (EWAS). This electrochemical process not only reduces sludge volume and pathogen content but also increases the concentration and bioavailability of essential nutrients (Jafari & Botte, 2021). In the context of sustainable agriculture, such electrochemical treatment supports the Nitrogen Circular Economy (NCE) — a framework aimed at improving nitrogen-use efficiency, recovering nutrients from waste streams, and closing nutrient loops in agricultural production (Rodriguez-Espinosa et al., 2023). TheAttorney Docket No.: 072253-92000 integration of EWAS into soil systems offers the potential to transform a wastewater byproduct into a high-value, slow-release fertilizer that supports sustainable nutrient cycling and mitigates environmental impacts associated with conventional fertilizers. Moreover, the integration of biosolids, manure, and food waste into soil systems offers the potential to transform a wastewater byproduct into a high-value, slow-release fertilizer that supports sustainable nutrient cycling and mitigates environmental impacts associated with conventional fertilizers.

[0010] Despite the promise of EWAS, significant knowledge gaps remain regarding its behavior in soil environments. Before widespread adoption, it is essential to understand how electrochemical treatment alters the physicochemical characteristics of WAS and, in turn, influences nutrient release, sorption, and mobility in soil matrices. Bench-scale and field-scale studies are necessary to assess nutrient speciation, solubility, and transformation dynamics following soil amendment. Comparative evaluations of EGROW from EWAS, untreated WAS, and conventional inorganic fertilizers are particularly important for elucidating the mechanisms governing nitrogen, phosphorus, and carbon mobility in amended soils. For instance, preliminary findings indicate that EWAS-amended soils may release a higher percentage of organic and total carbon relative to untreated WAS, potentially due to the structural deformation of organic matter induced by alkaline electrolysis. Furthermore, studies suggest that EWAS exhibits reduced ammonium adsorption capacity, likely reflecting alterations in the organic matter matrix. Phosphorus speciation analyses using X-ray absorption near edge structure (XANES) spectroscopy have identified struvite as a dominant mineral phase within EWAS and WAS solids, representing a novel aspect of this research and indicating a potential pathway for controlled phosphorus release.

[0011] The chemical complexity of EWAS and its interaction with soil components such as clay minerals, organic matter, and metal oxides demand a mechanistic understanding of nutrient mobility and retention. Of particular importance are the roles of organoclayAttorney Docket No.: 072253-92000 complexation, pH-dependent solubility, and redox dynamics in controlling nitrogen and phosphorus availability. The electrochemical treatment process may also influence the balance between labile and recalcitrant organic carbon pools, thereby affecting microbial activity and long-term soil fertility. The interplay among these factors will determine the agronomic effectiveness and environmental safety of EWAS as a fertilizer source.

[0012] Given the global imperatives of increasing food production, reducing nutrient losses, and recovering resources from waste streams, EWAS represents a promising step toward sustainable fertilizer development. However, to advance the integration of EWAS into agricultural practice, comprehensive evaluations of nutrient mobility, bioavailability, and soil interaction mechanisms are needed.

[0013] Accordingly, there is a critical need for methods and systems that elucidate the mobility of nitrogen, carbon, and phosphorus in soil systems amended with electrochemically treated waste activated sludge. Such methods must characterize nutrient release and sorption dynamics relative to conventional fertilizers, assess the influence of electrochemical treatment on nutrient speciation and solubility, and provide data to inform sustainable land application practices that minimize runoff and maximize nutrient use efficiency.SUMMARY OF THE DISCLOSURE

[0014] The present disclosure is directed to methods and systems for enhancing the mobility of nitrogen, carbon, and phosphorus in soil systems through the application of electrochemically treated waste activated sludge (EWAS), biosolids, manure, food waste or combinations thereof. In particular, the disclosure relates to the beneficial reuse of wastewater- derived biosolids that have undergone electrochemical treatment to increase nutrient solubility, bioavailability, and controlled release properties, thereby promoting sustainable nutrient management in agricultural environments.Attorney Docket No.: 072253-92000

[0015] To address the need described above, the present disclosure employs alkaline electrolysis processes for the treatment of waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof. The method can also be used for the pretreatment of waste related streams before an anaerobic digestor, enhancing the biogas capacity of the anerobic digestor while creating a functionalized fertilizer formulation with the properties described earlier.

[0016] Through electrochemical reactions performed under controlled conditions, including the use of alkaline electrolytes and metallic electrodes, the sludge is converted into a stabilized product — EWAS — with enhanced concentrations of bioavailable nitrogen, phosphorus, and carbon (the formulation can also include, is not limited to, sulfur (S), micronutrients (potassium (K), iron (Fe), calcium (Ca), and combinations thereof). The electrochemical treatment process not only reduces the overall volume and pathogen content of WAS, but also modifies the chemical and structural composition of the organic matter matrix, leading to improved nutrient release profiles when applied to soil.

[0017] The process can also be integrated before an anaerobic digestor, increasing the capacity for biogas production while providing an organic mineral fertilizer formulation. In certain embodiments, the organic mineral fertilizer formulation can be produced and formulated with different electrolytes, such as KOH, CaO, Ca(OH)2, iron sulfate, or combinations thereof, thereby improving the efficiency of the electrolysis process while incorporating micronutrients and functionalized groups into the “solid” fertilizer and / or the liquid formulation (e.g., solids with electrolyte).

[0018] The organic mineral fertilizer formulation can also, in certain embodiments, contain formulated long chain fatty acids (LCFAs). LCFAs are crucial for plant development and agriculture, serving as structural components of cell membranes, waxes, and seed storage lipids. In agriculture, this includes developing seed oils for food and animal feed, creatingAttorney Docket No.: 072253-92000 protective cuticles to prevent water loss, and using LCFAs to synthesize specific herbicides that control weeds by inhibiting seedling growth.

[0019] The organic mineral fertilizer formulation can also, in certain embodiments, contain formulated short chain fatty acids (SCFAs) and volatile fatty acids (VFAs). In such embodiments, the SCFAs and VFAs can serve as herbicides.

[0020] In certain embodiments, the EWAS produced through this process is applied to agricultural soils or potting mixes as a slow-release fertilizer. Comparative analyses of EWAS, untreated WAS, and conventional inorganic fertilizers demonstrate that EWAS-amended soils exhibit lower total nitrogen leaching, higher solubility of organic and total carbon, and unique phosphorus mineral phases, such as struvite and calcium-phosphate complexes, which contribute to nutrient retention and gradual release. The present systems and methods thus enable a controlled delivery of essential macronutrients while mitigating nutrient losses and environmental impacts associated with traditional fertilizer use.

[0021] The methods and systems of the present disclosure offer several advantages. First, by transforming waste activated sludge into a value-added fertilizer, the disclosed approach supports circular economy principles and promotes resource recovery from wastewater streams. Second, the enhanced solubility and mobility of nitrogen, carbon, and phosphorus in EWAS contribute to improved nutrient-use efficiency and reduced nutrient runoff, thereby protecting water quality. Third, the application of EWAS may increase dissolved organic carbon in soil, which supports microbial biodiversity and long-term soil health. Additionally, the slow-release characteristics of EWAS minimize the frequency of fertilizer application, leading to reduced input costs and greater operational efficiency for agricultural producers.

[0022] Collectively, the disclosed methods and systems advance sustainable agriculture by providing an economically viable, environmentally responsible, and scientifically validated pathway for nutrient recovery and soil enhancement. By integrating electrochemical treatmentAttorney Docket No.: 072253-92000 technologies with soil amendment practices, the present disclosure contributes to closing nutrient loops, reducing waste, and improving the resilience of food production systems.

[0023] In general embodiments, the present disclosure is directed a method for enhancing the mobility of nutrients in soil that includes providing waste, wherein the waste comprises one or more of waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof. The method can also include preparing an alkaline electrolyte solution comprising sodium hydroxide. The method can also include subjecting the waste to electrolysis in the alkaline electrolyte solution using a pair of electrodes positioned within a serpentine flow electrochemical cell operated at a cell potential of approximately ±2.5 volts with periodic polarity switching, thereby producing an organic mineral fertilizer formulation. The method can also include applying the organic mineral fertilizer formulation to a soil system selected from agricultural soil and potting mix at a rate of approximately 70 pounds nitrogen per acre. The organic mineral fertilizer formulation can include ammonium (NHA), nitrate (NCb ), and phosphorus in the form of struvite.

[0024] Implementations of the invention can include one or more of the following features:

[0025] The electrochemical treatment can include using sodium hydroxide, potassium hydroxide, CaO, calcium hydroxide, and / or iron sulfates combinations as an electrolyte.

[0026] The electrochemical treatment can be performed with electrodes that include one or more of nickel, copper, cobalt, chromium, stainless steel, silver, gold, transition metals, or combinations thereof.

[0027] The electrochemical treatment can be performed with electrodes in a serpentine flow cell.

[0028] The electrochemical treatment can release ammonium (NH4±) and nitrate (NO3-) into the organic mineral fertilizer formulation.

[0029] The organic mineral fertilizer formulation can promote slow-release of nitrogen intoAttorney Docket No.: 072253-92000 the soil system.

[0030] The organic mineral fertilizer formulation can increase dissolved organic carbon (DOC) in the soil system.

[0031] The increased dissolved organic carbon can promote microbial biodiversity in the soil.

[0032] The phosphorus in the organic mineral fertilizer formulation can be characterized by the formation of struvite.

[0033] The phosphorus can be further complexed with calcium-phosphate compounds.

[0034] The soil system can be agricultural soil or potting mix.

[0035] The agricultural soil can be calcareous soil.

[0036] The organic mineral fertilizer formulation can reduce nitrogen runoff compared to traditional fertilizers.

[0037] The organic mineral fertilizer formulation is introduced upstream of an anaerobic digester to increase biogas production while maintaining the nutrient profile of the formulation.

[0038] The organic mineral fertilizer formulation can have a moisture content between approximately 60 percent and 90 percent at the point of introduction upstream of the anaerobic digester.

[0039] The introduction of the organic mineral fertilizer formulation upstream of the anaerobic digester can increase methane generation by at least 10 percent relative to untreated sludge.

[0040] The electrochemical treatment used to produce the organic mineral fertilizer formulation can include using an alkaline electrolyte comprising potassium hydroxide (KOH), calcium oxide (CaO), calcium hydroxide (Ca(OH)2), iron sulfate, or combinations thereof.

[0041] The organic mineral fertilizer formulation can include long-chain fatty acids (LCFAs) functioning as structural agents to reduce volatilization and enhance soil retention.

[0042] The organic mineral fertilizer formulation can include short-chain fatty acids (SCFAs) and volatile fatty acids (VFAs) that promote microbial activity and act as bio-stimulants.Attorney Docket No.: 072253-92000

[0043] The organic mineral fertilizer formulation can be pathogen-reduced and stable against release of methane, volatile organic compounds, ammonia, or nitrous oxide.

[0044] In general, in another embodiment, the present invention is directed to a system producing and applying organic mineral fertilizer formulation to soil. The system can include an electrochemical treatment unit. The electrochemical treatment unit can include a reaction chamber configured as a serpentine flow cell. The electrochemical treatment unit can include a pair of electrodes disposed within the reaction chamber. The electrochemical treatment unit can include an alkaline electrolyte reservoir containing a sodium hydroxide solution. The electrochemical treatment unit can include a power supply operatively coupled to the electrodes and configured to apply a cell potential of approximately ±2.5 volts with polarity switching. The electrochemical treatment unit can include a sludge inlet and sludge outlet permitting the passage of waste through the reaction chamber during electrolysis to produce an organic mineral fertilizer formulation. The system can also include a soil distribution apparatus. The soil distribution apparatus can include a storage tank for receiving the organic mineral fertilizer formulation from the sludge outlet of the reaction chamber. The soil distribution apparatus can also include a delivery manifold connected to the storage tank and configured to apply the organic mineral fertilizer formulation to a soil system at a rate of approximately 70 pounds nitrogen per acre.

[0045] Implementations of the invention can include one or more of the following features:

[0046] The electrochemical cell can include electrodes that include one or more of nickel, copper, cobalt, chromium, stainless steel, silver, gold, transition metals, or combinations thereof.

[0047] The electrochemical cell can include a serpentine flow design for electrolysis.

[0048] The electrochemical cell can use sodium hydroxide as an electrolyte to perform the electrochemical treatment of waste activated sludge (WAS), biosolids, manure, food waste, orAttorney Docket No.: 072253-92000 combinations thereof.

[0049] The electrochemical cell can include polarity switching during the electrolysis process.

[0050] The electrochemical cell can reduce pathogen content and increase bioavailable nutrients in the organic mineral fertilizer formulation.

[0051] The soil application mechanism can include a distribution apparatus for evenly applying the organic mineral fertilizer formulation to the soil system at a rate of 701bs N per acre.

[0052] The electrochemical cell can be configured to treat waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof to achieve the organic mineral fertilizer formulation with enhanced nitrogen, carbon, and phosphorus mobility.

[0053] An anaerobic digester fluidly coupled upstream of the electrochemical treatment unit.

[0054] The organic mineral fertilizer formulation can have a moisture content between about 60 percent and 90 percent at the point of introduction upstream of the anaerobic digester.

[0055] The electrochemical treatment unit and the anaerobic digester can be integrated within a closed-loop processing line configured to reduce emissions of methane, ammonia, and volatile organic compounds during operation.

[0056] The electrochemical treatment unit can include an alkaline electrolyte selected from potassium hydroxide (KOH), calcium oxide (CaO), calcium hydroxide (Ca(OH)2), iron sulfate, or combinations thereof.

[0057] In general, in another embodiment, the present invention is directed to a fertilizer composition including an organic mineral matrix produced by electrochemical treatment of waste. The waste can include one or more of waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof. The composition can also include a nutrient fraction comprising nitrogen, phosphorus, carbon, and sulfur. The composition can also include micronutrients selected from potassium (K), iron (Fe), calcium (Ca), or combinations thereof. The fertilizer composition can be configured to provide controlled release of the nutrientAttorney Docket No.: 072253-92000 fraction upon application to soil.

[0058] Implementations of the invention can include one or more of the following features:

[0059] The phosphorus can include struvite.

[0060] The phosphorus can be further present as calcium-phosphate complexes.

[0061] The nitrogen can include ammonium (NHA) and nitrate (NCb ).

[0062] The fertilizer composition can include long-chain fatty acids (LCFAs) functioning as structural agents to reduce volatilization and enhance soil retention.

[0063] The fertilizer composition can include short-chain fatty acids (SCFAs) and volatile fatty acids (VFAs) that promote microbial activity and act as bio-stimulants.

[0064] The organic mineral matrix can be produced using an alkaline electrolyte comprising potassium hydroxide (KOH), calcium oxide (CaO), calcium hydroxide (Ca(OH)2), iron sulfate, or combinations thereof.

[0065] The fertilizer composition can be formulated for introduction upstream of an anaerobic digester to increase biogas production while preserving the nutrient profile of the fertilizer composition.

[0066] The fertilizer composition can have a moisture content between about 60 percent and about 90 percent at the point of introduction upstream of the anaerobic digester.

[0067] The fertilizer composition can be pathogen-reduced and stable against release of methane, volatile organic compounds, ammonia, or nitrous oxide during storage.BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Other advantages of the present disclosure will be apparent from the following detailed description of the disclosure in conjunction with embodiments as illustrated in the accompanying drawings, in which:Attorney Docket No.: 072253-92000

[0069] FIG. 1 depicts a process overview for producing fertilizers derived from WAS that has been electrochemically treated EWAS to reduce pathogens and release ammonium (NHv) and nitrate (NCh ), in accordance with certain embodiments of the present disclosure.

[0070] FIG. 2 depicts a schematic diagram of an electrolysis process-flow design for treatment of WAS to produce EWAS, in accordance with certain embodiments of the present disclosure.

[0071] FIGS. 3A-3C depict treatment effects on dissolved organic carbon (DOC) concentrations (mg L1), in accordance with certain embodiments of the present disclosure. FIG. 3A shows an agricultural soil system; FIG. 3B shows a potting mix system; FIG. 3C shows a no-soil system.

[0072] FIGS. 4A-4C depict treatment effects on total carbon released into solution (mg L1), in accordance with certain embodiments of the present disclosure. FIG. 4A shows an agricultural soil system; FIG. 4B shows a potting mix system; FIG. 4C shows a no-soil system.

[0073] FIGS. 5A-5C depict total nitrogen (TN) concentrations (mg L1), in accordance with certain embodiments of the present disclosure. FIG. 5A shows agricultural soil systems; FIG. 5B shows potting mix systems; FIG. 5C shows no-soil systems.

[0074] FIGS. 6A-6E depict treatment effects on released ammonium (NELL) and nitrate (NCb ) (mg L '), in accordance with certain embodiments of the present disclosure. FIG. 6A shows agricultural soil reaction filtrate; FIG. 6B shows potting mix reaction filtrate; FIG. 6C shows no-soil reaction filtrate; FIG. 6D shows agricultural soil rinse filtrate; FIG. 6E shows potting mix rinse filtrate.

[0075] FIG. 7 depicts treatment effects on ammonium adsorption to agricultural soil and potting mix (reaction filtrate only), in accordance with certain embodiments of the present disclosure.Attorney Docket No.: 072253-92000

[0076] FIG. 8 depicts normalized X-ray absorption spectra of EWAS, WAS, and NIST 2781 (Domestic Sludge Standard), in accordance with certain embodiments of the present disclosure. Dashed lines indicate: (I) whiteline position at 2153.3 eV, (II) a struvite-indicative shoulder at 2162 eV, and (III) an oxygen oscillation peak at 2170.0 eV.

[0077] FIGS. 9A-9B depict treatment effects on percent potassium removed from solution in agricultural soil and potting mix, in accordance with certain embodiments of the present disclosure. The percentage was calculated by dividing the amount of K released into solution from the sample by the sum of the amounts released by the fertilizer-only and soil-only controls.

[0078] FIG. 10 depicts treatment effects on percent phosphorus sorbed in agricultural soil and potting mix (reaction filtrate only), in accordance with certain embodiments of the present disclosure. Values were calculated by subtracting the amount of phosphorus released by the soil-only control from the amount released by the sample and dividing by the amount released by the fertilizer-only control.

[0079] FIGS. 11A-11B depict plant tissue biomass metrics, in accordance with certain embodiments of the present disclosure. FIG. 11A shows shoot dry weight; FIG. 11B shows root dry weight and total biomass for plants grown under the indicated treatments.

[0080] FIG. 12 depicts microbial biomass carbon for control, non-soil (ns), Dillodirt, WAS, and the EWAS product of the present disclosure, illustrating soil health responses comparable to composted materials and stimulation of microbial biomass relative to fertilizer-only controls, in accordance with certain embodiments of the present disclosure.NOTATION AND NOMECLATURE

[0081] Various terms are used to refer to particular system components. Different companies may refer to a component by different names - this document does not intend to distinguishAttorney Docket No.: 072253-92000 between components that differ in name but not function. In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . .” Also, the term “couple” or “couples” is intended to mean either an indirect or a direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection or through an indirect connection via other devices and connections.

[0082] The terminology used herein is for the purpose of describing particular example embodiments only, and is not intended to be limiting. Following long-standing patent law convention, the terms “a” and “an” mean “one or more” when used in this application, including the claims.

[0083] As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.

[0084] The terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and / or sections; however, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer, or section from another region, layer, or section. Terms such as “first,” “second,” and other numerical terms, when used herein, do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer, or section discussed below could be termed a second element, component, region, layer, or section without departing from the teachings of the example embodiments. The phrase “at least one of,” when used with a list of items, means that differentAttorney Docket No.: 072253-92000 combinations of one or more of the listed items may be used, and only one item in the list may be needed. As used herein, the term “and / or” when used in the context of a listing of entities, refers to the entities being present singly or in combination. Thus, for example, the phrase “A, B, C, and / or D” includes A, B, C, and D individually, but also includes any and all combinations and subcombinations of A, B, C, and D. Accordingly, as an example, “at least one of: A, B, and C” includes any of the following combinations: A, B, C, A and B, A and C, B and C, and A and B and C. In another example, the phrase “one or more” when used with a list of items means there may be one item or any suitable number of items exceeding one.

[0085] Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” “top,” “bottom,” and the like, may be used herein. These spatially relative terms can be used for ease of description to describe one element’s or feature’s relationship to another element(s) or feature(s) as illustrated in the figures. The spatially relative terms may also be intended to encompass different orientations of the device in use, or operation, in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptions used herein interpreted accordingly.

[0086] The following abbreviations and acronyms are used throughout this specification: WAS- Waste Activated Sludge; WWTP - Wastewater Treatment Plant; EWAS - Electrochemically Treated Waste Activated Sludge; NCE - Nitrogen Circular Economy; DOC - Dissolved Organic Carbon; TN - Total Nitrogen; TC - Total Carbon; SOM - Soil Organic Matter; DOM- Dissolved Organic Matter; XANES - X-ray Absorption Near Edge Structure; and EPA - Environmental Protection Agency.Attorney Docket No.: 072253-92000

[0087] For purposes of the present invention, a noble metal comprises gold, platinum, ruthenium, rhodium, palladium, osmium, and / or iridium, but may also include copper or silver, or any combination thereof.

[0088] As used herein, “E-GROW” means an organic mineral fertilizer formulation produced by the processes described and discussed in this disclosure to deliver carbon (C), nitrogen (N), phosphorus (P), sulfur (S), micronutrients (potassium (K), iron (Fe), calcium (Ca)).

[0089] As used herein, “EGR0W-AD+” means an organic mineral fertilizer formulation produced by the processes described and discussed in this disclosure to deliver carbon (C), nitrogen (N), phosphorus (P), sulfur (S), micronutrients (potassium (K), iron (Fe), calcium (Ca)) that is integrated before an anaerobic digester, increasing the capacity for biogas production.

[0090] For purposes of the present invention, a rectifier is an electrical device that converts alternating current (AC), which periodically reverses direction, to direct current (DC), which flows in only one direction.

[0091] Various aspects of the invention are described using the term “comprising;” however, in narrower embodiments, the invention may alternatively be described using the terms “consisting essentially of’ or, more narrowly, “consisting of.”

[0092] Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.DETAILED DESCRIPTION

[0093] The present disclosure relates to methods and systems for producing and applying anAttorney Docket No.: 072253-92000 organic mineral fertilizer formulation (E-GROW or, in certain embodiments, EGROW-AD+) to soil systems to enhance the mobility and availability of macronutrients, including nitrogen (N), carbon (C), and phosphorus (P). In various embodiments, the an organic mineral fertilizer formulation, (which can include electrochemically treated waste activated sludge (EWAS)) is generated by subjecting waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof to alkaline electrolysis to form EWAS and subsequently applying the resulting EWAS to agricultural soil or potting media as a fertilizer material (EGROW, or in embodiments integrated before an anaerobic digester, EGROW-AD+).

[0094] As used herein, WAS denotes sludge comprising biomass and associated solids recovered from an activated sludge process; EWAS denotes the solid fraction obtained after electrochemical treatment of WAS under alkaline conditions and subsequent separation / conditioning steps; and soil system encompasses agricultural field soils (e.g., calcareous soils) and horticultural growth media (e.g., peat-perlite potting mixes). E-GROW denotes an organic mineral fertilizer formulation produced by the processes described and discussed in this disclosure to deliver carbon (C), nitrogen (N), phosphorus (P), sulfur (S), micronutrients (potassium (K), iron (Fe), calcium (Ca)). EGR0W-AD+ denotes an organic mineral fertilizer formulation produced by the processes described and discussed in this disclosure to deliver carbon (C), nitrogen (N), phosphorus (P), sulfur (S), micronutrients (potassium (K), iron (Fe), calcium (Ca)) that is integrated before an anaerobic digester, increasing the capacity for biogas production. Unless the context indicates otherwise, quantities and operating parameters may be “about” the stated values.

[0095] In certain method embodiments, WAS is combined with an alkaline electrolyte and subjected to electrolysis using metallic electrodes to produce EWAS. In exemplary embodiments consistent with the claims, the electrolyte comprises sodium hydroxide and the electrodes comprise nickel plates arranged within a serpentine-flow electrochemical cell. TheAttorney Docket No.: 072253-92000 cell is driven at a bidirectional cell potential of approximately ±2.5 volts with periodic polarity switching to promote alternating oxidation-reduction at the electrode surfaces. The electrochemical treatment yields a stabilized biosolid in which soluble nitrogen species are present predominantly as ammonium (NTLT) and nitrate (NCh ) and phosphorus is present, at least in part, as struvite.

[0096] Following electrolysis, the treated slurry may be conditioned to obtain the E-GROW or EGR0W-AD±, an organic mineral fertilizer formulation, which can offer a number of advantages over prior fertilizer formulations. In some embodiments, the E-GROW and / or EGR0W-AD± provide more efficient plant growth than compost, immediate nitrogen (N) release combined with slow-release nitrogen (N) fertilizer, releasing effective ammonium (NH4+) to the soil instead of nitrates, and an excellent source of carbon for the soil. In some embodiments, in conjunction with or alternative to the prior embodiments, the E-GROW and / or EGROW-AD± can serve as a nitrogen (N) and phosphorous (P) storage for plant use reducing nutrients release to the environment. In some embodiments, in conjunction with or alternative to the prior embodiments, the E-GROW and / or EGR0W-AD± are pathogen-free, ensuring it is a safe product for both crops and the environment. In some embodiments, in conjunction with or alternative to the prior embodiments, the E-GROW and / or EGR0W-AD± have microstructures that can enable enhanced soil productivity through carbon retention, such as for example, but not limited to approximately 0.03 t carbon equivalent per t of E-GROW, 50% humidity. In some embodiments, in conjunction with or alternative to the prior embodiments, the E-GROW and / or EGR0W-AD± have a stable formulation that prevents production of harmful gases (methane, VOCs, ammonia, N2O), ensuring regulatory compliance.

[0097] In some embodiments, the production of E-GROW and / or EGR0W-AD± results from formulation using electrolytes, such as for example, but not limited to, KOH, CaO, Ca(OH)2, iron sulfate, etc., thereby improving the efficiency of the electrolysis process whileAttorney Docket No.: 072253-92000 incorporating micronutrients and functionalized groups into the “solid” fertilizer and / or the liquid formulation (e.g., solids with electrolyte).

[0098] In some embodiments, the organic mineral fertilizer formulation can also contain formulated long chain fatty acids (LCFAs). LCFAs are crucial for plant development and agriculture, serving as structural components of cell membranes, waxes, and seed storage lipids. In agriculture, this includes developing seed oils for food and animal feed, creating protective cuticles to prevent water loss, and using LCFAs to synthesize specific herbicides that control weeds by inhibiting seedling growth. The E-GROW can also, in some embodiments, contain formulated short chain fatty acids (SCFAs) and volatile fatty acids (VFAs). The SCFAs and VFAs can serve as herbicide.

[0099] In certain embodiments, such as those processes facilitating the production of EGROW- AD+, the process can also be integrated before an anaerobic digester, increasing the capacity for biogas production while providing a formulation that provides the advantages noted above in this disclosure.

[0100] . In some embodiments, conditioning includes pH adjustment to a near-neutral range (e.g., pH approximately 8) and a solid-liquid separation step (e.g., centrifugation, filtration, or settling) to recover the EWAS solids suitable for handling, storage, and field application. Optionally, moisture content may be reduced by dewatering or drying operations to facilitate transport or blending.

[0101] In application embodiments, the E-GROW and / or EGR0W-AD+ is metered to a soil system on an equal-nitrogen basis relative to a target agronomic rate. In an illustrative embodiment, EWAS is applied at a rate corresponding to approximately 70 pounds of nitrogen per acre for small-grain production of the organic mineral fertilizer formulation; however, rates may be adjusted according to soil testing, crop demand, and local best management practices. EWAS may be applied alone or in combination with other nutrient sources and may beAttorney Docket No.: 072253-92000 broadcast, banded, incorporated, or top-dressed. The disclosed methods are suitable for soils having a range of textures and chemical properties, including calcareous soils typical of semi- arid regions.

[0102] System embodiments include an electrochemical treatment unit and a soil distribution apparatus. The treatment unit comprises a reaction chamber configured as a serpentine flow cell, a pair of electrodes disposed within the chamber, an alkaline electrolyte reservoir containing a sodium hydroxide solution, a pump for slurry circulation, and a power supply operatively coupled to the electrodes to apply a cell potential of approximately ±2.5 volts with polarity switching. The electrodes may include one or more of nickel, copper, cobalt, chromium, stainless steel, silver, gold, transition metals, or combinations thereof. The soil distribution apparatus can include a storage vessel receiving EWAS from the treatment unit and a delivery manifold or spreader capable of metering EWAS to soil at a selected nitrogen application rate.

[0103] Without limitation, the methods and systems disclosed herein support fertilizer programs emphasizing gradual nutrient availability and resource recovery. In particular, the electrochemical treatment of WAS, biosolids, manure, food waste, or combinations thereof under alkaline conditions yields an EWAS product that provides plant-available nitrogen species and phosphorus associated with sparingly soluble minerals, while supplying organic carbon that contributes to soil conditioning. The disclosed production and application steps are compatible with municipal biosolids programs and agricultural operations seeking to implement circular nutrient management to provide an organic mineral fertilizer formulation.

[0104] FIG. 1 depicts, in accordance with certain embodiments, a schematic process 100 for producing fertilizers (EGROW) derived from waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof that has been electrochemically treated (EWAS) to reduce pathogens and to release ammonium (NHv) and nitrate (NOs ). In the illustratedAttorney Docket No.: 072253-92000 embodiment, element 101 denotes the EWAS product, element 102 denotes a nutrient-release stage associated with phosphorus (P), ammonium (NHA), and nitrate (NCh ), and element 103 denotes soil. In some embodiments, WAS and EWAS are applied to agricultural soil and potting media in an E-GROW fertilizer product, and aqueous phases recovered from the amended matrices are analyzed to determine nitrogen, phosphorus, carbon, and other nutrients adsorbed to the solid phase and released to solution.

[0105] In certain embodiments, inorganic and naturally derived fertilizers (E-GROW and / or EGR0W-AD+) are included as comparators to assess soil chemistry dynamics relative to EWAS and WAS. In working examples, to effectively characterize and examine the potential of this new E-GROW and / or EGR0W-AD+ fertilizer, batch sorption experiments were performed via a two-factor (fertilizer and soil type) factorial design as shown in Table 1 below.Fertilizer Soil TypeEWAS Ag SoilWAS Ag SoilGreenview Ag SoilMilorganite Ag SoilNone (control) Ag SoilEWAS Potting MixWAS Potting MixGreenview Potting MixMilorganite Potting MixNone (control) Potting MixEWAS No Soil (control)WAS No Soil (control)Greenview No Soil (control)Milorganite No Soil (control)None (control) No Soil (control)

[0106] FIG. 2 depicts, in certain embodiments, a schematic process 200 for electrochemical treatment of a WAS slurry to produce EWAS. In the illustrated arrangement, a power source 201 is operatively coupled to an electrochemical cell 202 through which the WAS slurry is circulated by a pump 203 from a stirred tank reactor 204 containing the homogenized WAS solution. In some embodiments, the slurry is conveyed through the cell at a volumetric flowAttorney Docket No.: 072253-92000 rate of about 18 L min1(corresponding to a linear velocity of about 0.75 m s-1). In certain embodiments, the power source 201 applies symmetric, bidirectional cell-potential pulses of approximately ±2.5 V for a treatment duration of about 2 hours, with polarity switching at intervals of about 10 seconds to promote desorption of surface species and maintain electrode activity during alternating oxidation and reduction. In some embodiments, electrolysis is conducted near atmospheric pressure at a temperature of about 20 °C. Following electrolysis, the treated slurry can be conditioned by pH adjustment (e.g., to about pH 8) and phase separation (e.g., centrifugation or filtration) to recover the EWAS solids for subsequent use. In one embodiment, the recovered EWAS exhibits a moisture content of about 90% and a nitrogen content of about 2% on a dry-mass basis.

[0107] In some embodiments, phosphorus speciation in EWAS and WAS solids is characterized by X-ray absorption near-edge structure (XANES) spectroscopy. In representative results, EWAS- and WAS-amended samples release less total nitrogen to solution than comparator treatments, which is attributable to organoclay complexation of nitrogen-containing biomolecules and to differences in nitrogen solubility across fertilizer types. In further embodiments, EWAS-amended samples release a higher proportion of organic and total carbon to solution, consistent with electrochemically induced modification of organic- matter structure under alkaline conditions. Electrochemical treatment can increase the solubility of nitrogen and carbon present in sludge. In some embodiments, soils treated with EWAS exhibit reduced ammonium adsorption relative to comparators, consistent with altered organic-matter binding functionality. In certain embodiments, phosphorus present in EWAS and WAS solids is identified as struvite; high levels of phosphorus complexation are observed, for example due to formation of low-solubility calcium-phosphate phases and sorption by clay minerals.

[0108] As noted above in respect to FIG. 2, in certain embodiments, EWAS can be producedAttorney Docket No.: 072253-92000 from WAS by subjecting a homogenized alkaline slurry of WAS to electrolysis in a flow cell. By way of example, the WAS can be maintained under refrigeration prior to treatment. In certain embodiments, an alkaline electrolyte solution comprises approximately 0.2 M sodium hydroxide. In some embodiments, a pair of electrodes is positioned across a serpentine flow path within an electrochemical cell. The electrodes may be made of one or more of nickel, copper, cobalt, chromium, stainless steel, silver, gold, transition metals, or combinations thereof. Prior to assembly, electrode surfaces can be roughened to increase active area and remove surface oxides. In one embodiment, a slurry is prepared by combining approximately 965 g of WAS with approximately 3.2 L of the alkaline electrolyte and agitating to achieve homogenization.

[0109] In some embodiments, in accordance with the system depicted in FIG. 2, the slurry is circulated through the electrochemical cell at a volumetric flow rate of about 18 L min-1(corresponding to a linear velocity of about 0.75 m s-1). In certain embodiments, symmetric cell-potential pulses of approximately ±2.5 V are applied across the electrodes for a duration of about 2 hours with periodic polarity switching at intervals of about 10 seconds to promote desorption of surface species and to maintain electrode activity during alternating oxidation and reduction. In some embodiments, electrolysis is performed at approximately 20 °C and near-atmospheric pressure.

[0110] Upon completion of electrolysis, the slurry pH can be adjusted, for example to approximately 8, by addition of an acid. In certain embodiments, the treated slurry is subjected to phase separation by centrifugation to isolate the solid EWAS fraction for subsequent use. In one embodiment, the recovered EWAS exhibits a water content of about 90% and a nitrogen content of about 2% on a dry-mass basis.[OHl] In some embodiments, the agronomic performance and sorption behavior of EWAS are evaluated using a factorial design that varies fertilizer type and growth medium. By way ofAttorney Docket No.: 072253-92000 example, fertilizer factors can include EWAS, WAS, an inorganic mineral fertilizer, and a naturally derived biosolids-based fertilizer; media factors can include agricultural soil, potting mix, and a no-soil control. In certain embodiments, soil-only and potting-only controls are included. Each fertilizer can be applied on an equal -nitrogen basis corresponding, for example, to approximately 70 pounds N per acre.

[0112] In some embodiments, agricultural soil is collected from the surface horizon (e.g., 0-20 cm), air-dried, and sieved to remove coarse fragments. In certain embodiments, the soil exhibits a sandy clay loam texture, a pH of about 7.6, a cation-exchange capacity of about 14.9 meq per 100 g, and an organic-matter content of about 1.2%, with dominant clay minerals including illite and interlayered illite-smectite with lesser kaolinite. In some embodiments, a peat-perlite- vermiculite potting mix is used to assess media effects. In certain embodiments, a background electrolyte (e.g., approximately 10 mM calcium chloride) is employed during batch contact to standardize ionic strength.

[0113] In some embodiments, fertilizers are dosed to achieve the equal-nitrogen application rate, which can correspond, by way of example, to approximately 0.84 mg inorganic fertilizer per 3 g soil, approximately 1.40 mg naturally derived fertilizer per 3 g soil, approximately 41.97 mg EWAS per 3 g soil, and approximately 5.97 mg WAS per 3 g soil. In certain embodiments, replicate contact tests are conducted at contact times of about 24 hours and about 48 hours. Following contact, suspensions can be clarified (e.g, by centrifugation) and filtered to obtain reaction filtrates. In some embodiments, residual solids are rinsed with the background electrolyte, resuspended, and clarified to obtain rinse filtrates indicative of loosely bound species. In certain embodiments, reaction and rinse filtrates are analyzed to quantify dissolved ammonium, nitrate, total nitrogen, dissolved organic carbon, total carbon, phosphorus, potassium, and other analytes of interest using standard analytical techniques.

[0114] In some embodiments, ammonium is determined colorimetrically by reaction with aAttorney Docket No.: 072253-92000 salicylate-nitroprusside system under alkaline hypochlorite conditions and measurement at a wavelength of about 650 nm; nitrate is determined colorimetrically following reduction and Griess-based dye formation and measurement at a wavelength of about 540 nm. In certain embodiments, dissolved organic carbon and total carbon are determined by catalytic combustion with non-dispersive infrared detection, with inorganic carbon removed by acid sparging; in the context of soil extractions, non-purgeable organic carbon corresponds to dissolved organic carbon. In some embodiments, total nitrogen is determined by chemiluminescence following oxidation to nitric oxide and reaction with ozone. In certain embodiments, phosphorus K-edge XANES spectra are acquired on pressed pellets of the dried solids under vacuum using a partial electron-yield detector; spectra are collected across preedge, edge, and post-edge regions with fine energy spacing at the edge, calibrated to a phosphate standard, and processed using standard X-ray absorption analysis workflows to fingerprint phosphorus species present in the samples.

[0115] FIGS. 3A-3C illustrate treatment effects on dissolved organic carbon (DOC) concentrations for agricultural soil systems, potting-mix systems, and fertilizer-only systems. Table 2, below, shows the percent DOC released into solution from the soil or potting mix in working examples.Sample % DOC from % DOC from soil / potting- 24h soil / potting- 48hAg. Soil + Milorganite 61 64Ag. Soil + Greenview 67 69Ag. Soil + EWAS 35 36Ag. Soil + WAS 62 75Potting Mix + Milorganite 64 67Potting Mix + Greenview 64 69Potting Mix + EW AS 39 35Potting Mix + WAS 56 71

[0116] As shown above, in certain embodiments, when soil or potting mix is present, a majority of DOC measured in solution originates from the soil matrix rather than the fertilizer source,Attorney Docket No.: 072253-92000 except in the case of samples amended with EWAS. In representative evaluations without soil, such as for example in FIG. 3C, EWAS releases more DOC than natural, inorganic, or untreated WAS fertilizers. By way of example, EWAS releases on the order of approximately 45% and 40% more DOC than a natural fertilizer at about 24 h and about 48 h, respectively; approximately 56% and 58% more than an inorganic fertilizer at about 24 h and about 48 h, respectively; and approximately 46% and 59% more than WAS at about 24 h and about 48 h, respectively. In certain embodiments, increased DOC released to the soil solution is expected to improve soil structure and water retention and to stimulate microbial biodiversity and biomass, thereby contributing to overall soil health. These observations are consistent with alkaline electrochemical treatment altering the structure of organic matter in EWAS, increasing the solubility of humic substances relative to WAS.

[0117] In some embodiments, the observed increase in carbon release is explained by pH- mediated changes in soil organic matter (SOM) interactions. As pH increases, van der Waals forces that promote SOM aggregation can weaken, and ionization of carboxylic and phenolic functional groups can increase, producing electrostatic repulsion and dispersion. In certain embodiments, SOM molecules thereby align and rearrange from aggregated or fibrous structures toward more sheet-like structures, with an accompanying decrease in particle size, which enhances solubilization. Consistent with this mechanism, WAS — which has not undergone alkaline electrochemical treatment — releases less DOC than EWAS. In further embodiments, in fertilizer-only systems, DOC values in rinse filtrates for EWAS and WAS are lower than initial reaction filtrates, indicating that a larger fraction of organic carbon is labile in the initial contact period.

[0118] In some embodiments, fertilizer application does not substantially alter bulk pH of the soil or potting media during contact. By way of example, fertilizer-only systems exhibit average initial and post-reaction pH values of about 6.54 ± 0.56 and about 6.51 ± 0.69,Attorney Docket No.: 072253-92000 respectively; agricultural soil systems exhibit about 7.44 ± 0.23 initially and about 7.52 ± 0.27 post-reaction; and potting-mix systems exhibit about 7.44 ± 0.22 initially and about 7.62 ± 0.19 post-reaction. In certain embodiments, the buffering capacities of the soil and potting media compensate for any slight acidity associated with the fertilizers, yielding no statistically meaningful pH shift over the reaction period.

[0119] In accordance with some embodiments, FIGS. 4A-4C illustrate treatment effects on total carbon (TC) released to solution. In systems containing agricultural soil or potting mix, contact time can influence TC release. As shown below, Table 3 presents the percent TC released into solution from the soil or potting mix.Sample % TC from % TC fromAg. Soil + Milorganite 63 64Ag. Soil + Greenview 65 69Ag. Soil + EWAS 35 39Ag. Soil + WAS 59 75Potting Mix + Milorganite 71 65Potting Mix + Greenview 65 66Potting Mix + EWAS 36 34Potting Mix + WAS 54 70

[0120] By way of example, agricultural-soil systems exhibit an average increase of approximately 12.2% in TC between about 24 h and about 48 h, while potting-mix systems exhibit an average increase of approximately 7.2% over the same interval. In certain embodiments, the increase is attributable, at least in part, to progressive disruption of soil microaggregates that protect sorbed organic and inorganic constituents; application of mechanical energy during batch contact can break interparticle bonds and release occluded organic carbon. Additional contributions can arise from time-dependent dissolution of carbon from carbonate minerals or SOM and from acid generated by nitrification reactions, which can promote carbonate or SOM dissolution and consequent carbon release.

[0121] In some embodiments, data indicate that EWAS releases a higher percentage of totalAttorney Docket No.: 072253-92000 carbon to solution than natural, inorganic, or WAS fertilizers when soil or potting mix is present, demonstrating that a larger share of the measured carbon in EWAS-amended systems derives from the fertilizer source rather than the matrix. These findings are consistent with EWAS having increased carbon solubility relative to WAS due to electrochemical treatment under alkaline conditions.

[0122] In some embodiments, data from fertilizer-only systems, such as those in FIG. 4C, further evidence that EWAS releases more soluble carbon than other treatments. Without being bound by theory, this behavior is attributed to alteration of organic-matter structure under alkaline electrochemical conditions, which increases carbon solubility relative to untreated WAS. By way of example, in systems without soil or potting mix, EWAS releases approximately 36,639 mg C kg1and 38,231 mg C kg1at about 24 h and about 48 h, respectively, whereas WAS releases approximately 165,086 mg C kg1and 117,931 mg C kg1at about 24 h and about 48 h, respectively. These results indicate that electrochemical treatment increases the solubility of carbon present in sludge.

[0123] In certain embodiments, analysis of the ratio of DOC to TC, as shown in Table 4 below, shows that TC values exceed DOC values across treatments, indicating the presence of inorganic carbon while the majority of the total carbon pool remains organic.Sample % DOC of Total % DOC of TotalCarbon- 24h Carbon- 48hAg. Soil + Milorganite 81 83Ag. Soil + Greenview 88 80Ag. Soil + EWAS 86 78Ag. Soil + WAS 81 81Ag. Soil Only 82 80Potting Mix + 87 87MilorganitePotting Mix + 81 89GreenviewPotting Mix + EWAS 91 85Potting Mix + WAS 79 84Potting Mix Only 83 85No Soil + Milorganite 86 84No Soil + Greenview 82 79Attorney Docket No.: 072253-92000No Soil + EWAS 87 83No Soil + WAS 73 81No Soil Only 80 79

[0124] In some embodiments, the inorganic carbon fraction is attributed to carbonate minerals in agricultural soils (e.g., calcite) and to minerals containing inorganic carbon in potting media (e.g., vermiculite). In particular embodiments using calcareous field soils, higher inorganic carbon is observed relative to potting-mix or fertilizer-only systems, consistent with local soil conditions.

[0125] FIGS. 5A-5C illustrate, in certain embodiments, treatment effects on total nitrogen (TN) released to solution for agricultural-soil systems (FIG. 5A), potting-mix systems (FIG. 5B), and fertilizer-only systems (FIG. 5C). In some embodiments employing agricultural soil and EWAS or WAS, a portion of the measured TN is derived from the soil matrix rather than solely from the applied fertilizer, as shown in Table 5 below, which shows the TN released into solution from the soil or potting mix.Sample % TN from % TN fromSoil / Potting Mix- 24h Soil / Potting Mix- 48hAg. Soil + EWAS 44% 44%Ag. Soil + WAS 40% 55%Potting Mix + EWAS 34% 36%Potting Mix + WAS 40% 56%

[0126] Compared to natural and inorganic fertilizers applied on an equal -nitrogen basis, EWAS- and WAS-amended systems release less total nitrogen to solution. If extrapolated to field conditions, the lower TN release suggests a potential reduction in nitrogen runoff relative to conventional fertilizers.

[0127] The reduced TN release observed for EWAS and WAS is attributed, at least in part, to differences in nitrogen speciation and solubility among fertilizers. In certain embodiments, natural and inorganic fertilizers release nitrogen predominantly as readily soluble ammonium and nitrate, whereas EWAS and WAS contain a greater fraction of organic nitrogen speciesAttorney Docket No.: 072253-92000 that are less soluble in water. In some embodiments, organic matter added to soil or potting media associates with clay minerals, protecting nitrogen-containing biomolecules from loss to solution.

[0128] Although mechanical agitation can disrupt soil microaggregates and release occluded material, it is believed that rapid adsorption of nitrogen-rich biomolecules (e.g., proteins, polypeptides, nucleic acids) to reactive clay and oxide surfaces — via electrostatic interactions, hydrogen bonding, van der Waals forces, and hydrophobic affinity — limits their desorption under the contact conditions employed, thereby decreasing TN measured in solution. Such organoclay and organomineral complexation can also enhance soil resilience by stabilizing soil organic matter.

[0129] In fertilizer-only systems, such as those depicted in FIG. 5C, similar trends are observed, where as shown EWAS- and WAS-amended samples yield less TN in solution than samples amended with natural or inorganic fertilizers.

[0130] By way of example, EWAS releases approximately 7,600 mg soluble N-kg1(about 38% of total nitrogen) at about 24 h and approximately 7,746 mg soluble N-kg1(about 39% of total nitrogen) at about 48 h. WAS releases approximately 47,828.8 mg soluble N-kg1(about 74% of total nitrogen) at about 24 h and approximately 38,275.9 mg soluble N-kg1(about 59% of total nitrogen) at about 48 h.

[0131] In the absence of a soil matrix capable of colloidal complexation, these differences are attributed to the intrinsic solubilities of nitrogen forms present in each fertilizer and to the effects of electrochemical treatment. In particular embodiments, natural and inorganic fertilizers consist largely of ammonium and nitrate, whereas EWAS and WAS retain a higher proportion of organic nitrogen species that exhibit lower aqueous solubility.

[0132] In some embodiments, electrochemical treatment slightly increases nitrogen solubility in the sludge while maintaining a speciation profile distinct from purely inorganic sources.Attorney Docket No.: 072253-92000

[0133] FIGS. 6A-6E illustrate, in certain embodiments, treatment effects on released ammonium (NH4+) and nitrate (NCh ) (mg- L1) for agricultural-soil reaction filtrates (FIG. 6 A), potting-mix reaction filtrates (FIG. 6B), fertilizer-only reaction filtrates (FIG. 6C), agricultural- soil rinse filtrates (FIG. 6D), and potting-mix rinse filtrates (FIG. 6E).

[0134] In some embodiments employing soil or potting mix with a naturally derived fertilizer, nitrogen released to solution is predominantly in the form of nitrate. In contrast, an inorganic fertilizer releases nitrogen in proportions approximating half nitrate and half ammonium. For EWAS- and WAS-amended systems, a greater portion of nitrogen released is observed as nitrate rather than ammonium. Soil-only controls release nitrogen almost exclusively as nitrate.

[0135] Table 6, below, shows the proportions of ammonium and nitrate released into solution from all samples, as well as their corresponding ratios of ammonium to nitrate, as to the reaction filtrate.Sample % NH4+% NOf Ratio NH4+:NO3’Released ReleasedNat + Ag. Soil- 24h 10% 90% 1 :9Nat + Ag. Soil- 48h 0% 100% 0: 100Inorg + Ag. Soil- 24h 53% 47% 53:47Inorg + Ag. Soil- 48h 46% 54% 46:54EWAS + Ag. Soil- 24h 28% 72% 7: 18EWAS + Ag. Soil- 48h 19% 81% 19:81WAS + Ag. Soil- 24h 22% 78% 11 :39WAS + Ag. Soil- 48h 15% 85% 3: 17Nat + Potting- 24h 10% 90% 1 :9Nat + Potting- 48h 0% 100% 0: 100Inorg + Potting- 24h 53% 47% 53:47Inorg + Potting- 48h 47% 53% 47:53EWAS + Potting- 24h 27% 73% 27:73EWAS + Potting- 48h 22% 78% 11 :39WAS + Potting- 24h 27% 73% 27:73WAS + Potting- 48h 17% 83% 17:83Nat + No Soil- 24h 38% 62% 19:31Nat + No Soil- 48h 38% 62% 19:31Inorg + No Soil- 24h 84% 16% 21 :4Inorg + No Soil- 48h 82% 18% 41 :9EWAS + No Soil- 24h 100% 0% 100:0EWAS + No Soil- 48h 100% 0% 100:0Attorney Docket No.: 072253-92000WAS + No Soil- 24h 100% 0% 100:0WAS + No Soil- 48h 100% 0% 100:0

[0136] In certain embodiments, such as, for example, in FIGS. 6A and 6B, the temporal evolution of reaction filtrates shows decreasing ammonium concentrations and increasing nitrate concentrations between earlier and later sampling points, substantially independent of fertilizer type. Without being bound by theory, this trend is consistent with nitrification pathways wherein ammonia-oxidizing and nitrite-oxidizing microorganisms transform ammonium / ammonia to nitrate. In some embodiments, the observed decrease in dissolved ammonium also correlates with increased ammonium adsorption to the solid phase over time.

[0137] FIG. 7 depicts, in certain embodiments, treatment effects on ammonium adsorption in agricultural soil and potting mix, based on reaction filtrates. As used herein, ammonium adsorption reflects the difference between ammonium released by the composite system and ammonium released by the soil alone, normalized by ammonium released by the fertilizer alone. In some embodiments, ammonium ions are retained by cation-exchange and surface- complexation processes at clay-mineral basal planes and edge sites and by functional groups in soil organic matter. Ammonium may also enter the interlayer space of swelling clays (e.g., smectites), where exchangeable retention can occur; partial interlayer collapse can effect fixation, rendering ammonium temporarily unavailable for exchange. In soils comprising illite, interlayered illite-smectite, and vermiculite, these minerals exhibit significant capacity to complex ammonium.

[0138] In fertilizer-only reaction filtrates, such as those in FIG. 6C, EWAS- and WAS- amended samples release ammonium without detectable nitrate under the stated conditions, indicating that nitrogen in these materials is present in forms that are less immediately soluble than in natural or inorganic fertilizers. In certain embodiments, comparing EWAS to WAS shows that electrolysis under alkaline conditions does not materially alter aqueous-phaseAttorney Docket No.: 072253-92000 ammonium / nitrate speciation during initial release, nor the overall ammonium-to-nitrate ratio under fertilizer-only conditions. These findings suggest, in some embodiments, that EWAS nitrogen more readily associates with soil colloids in field applications, reducing leaching and runoff relative to readily soluble nitrate sources. The absence of nitrate in fertilizer-only systems is further consistent with denitrification during production or storage of biosolids- derived materials.

[0139] In rinse filtrates containing soil or potting mix, such as those in FIGS. 6D and 6E, nitrogen released to solution is observed predominantly as ammonium across treatments. Without being limiting, nitrate’s higher intrinsic aqueous solubility and strong hydration promote its earlier release during the initial reaction contact, whereas ammonium is more strongly retained by exchange sites and is liberated more gradually. In some embodiments, the presence of divalent cations (e.g., Ca2+) in the rinse solution competitively displaces exchangeable NHA from surface sites, desorbing ammonium that is not fixed within interlayers. Differences in instrumental detection limits between total -nitrogen and ion-specific colorimetric assays can account for instances where ammonium is detected while bulk TN in corresponding rinses is not resolved.

[0140] When comparing ammonium-adsorption responses across fertilizers, as shown in FIG. 7, several embodiments are observed. Samples treated with a naturally derived fertilizer exhibit relatively high ammonium adsorption (on the order of about 62-100%), which is attributed to abundant cation-binding functionality in the organic matrix. In contrast, EWAS-amended samples exhibit the lowest ammonium adsorption among the treatments, consistent with electrochemically induced disruption of organic-matter structure under alkaline conditions reducing the density or accessibility of binding sites. Inorganic-fertilizer-amended samples exhibit lower ammonium adsorption than naturally derived fertilizer, which is attributed to the high solubility of ammonium salts (for example, but not limited to, diammonium phosphate,Attorney Docket No.: 072253-92000 ammonium sulfate) that favors persistence in solution. WAS-amended samples exhibit less ammonium adsorption than naturally derived fertilizer despite the absence of electrochemical treatment, which, in some embodiments, is attributed to competitive adsorption by sodium ions; NHA and Na+can compete for exchange sites, reducing net ammonium retention.

[0141] Potassium (K) is, in certain embodiments, recognized as a limiting macronutrient for plant growth and productivity. Potassium participates in activation of numerous enzymes and modulates plant water relations by lowering cellular osmotic potential. Accordingly, management of potassium availability is an aspect of the disclosed systems and methods.

[0142] FIGS. 9A-9B illustrate, in some embodiments, treatment effects on the percentage of potassium removed from solution in agricultural soil and potting-mix systems. As used herein, the percentage removed is calculated relative to the summed potassium released by fertilizer- only and soil-only controls. In representative evaluations, varying amounts of potassium are observed to partition to naturally derived fertilizers — including EWAS and WAS — and, to a lesser extent, a composted biosolids product, substantially independent of the growth medium.

[0143] In certain embodiments the observed potassium partitioning is attributed to inhibition of K+diffusion from clay interlayers into solution due to organic-carbon surface coatings. Dissolved humic substances and other organic constituents can associate with charged clay surfaces to form bilayer-type coatings that reduce interlayer permeability, thereby impeding K+diffusion. In addition, iron-oxide coatings on clay particles can impart positive surface charge, attracting negatively charged functional groups (e.g., carboxylates) present in EWAS, WAS, and naturally derived fertilizers. Further, divalent cation bridging (e.g., Ca2+) can partially neutralize clay surface charge while leaving adsorption sites available for organic matter association. Collectively, these mechanisms enhance organic-carbon coatings on clay particles and, in some embodiments, explain decreased potassium measured in solution. While such organomineral complexes can be beneficial to soil structure and resilience, the potential forAttorney Docket No.: 072253-92000 potassium fixation and reduced plant availability may warrant monitoring where EWAS or WAS is applied.

[0144] In some embodiments, WAS-amended systems exhibit increased sodium adsorption from the soil matrix relative to other treatments, which is attributed to a greater abundance or preservation of cation-binding sites in the organic matter. By contrast, EWAS- and heat-treated biosolids may exhibit altered organic-matter surface structures and reduced densities of such binding sites, resulting in comparatively lower sodium adsorption. Notwithstanding these observations, under the stated experimental conditions the exchangeable sodium percentage (ESP) for agricultural soils amended with EWAS is about 0.2% at both ~24 h and ~48 h, and the ESP for soils amended with WAS is about 0.06% at both ~24 h and ~48 h — values well below the -15% threshold commonly used to classify soils as sodic.

[0145] FIG. 8 illustrates normalized phosphorus K-edge X-ray absorption spectra acquired for EWAS, WAS, and NIST 2781 (domestic sludge standard). In certain embodiments, each spectrum exhibits a principal “whiteline” peak near about 2153.3 eV; the NIST 2781 whiteline intensity may be slightly higher than the EWAS or WAS intensities. In some embodiments, the EWAS whiteline exhibits a minor shift to lower energy, which can indicate a slight reduction in the average phosphorus electronic environment while maintaining an overall phosphorus oxidation state of approximately +5 for all samples. A pre-edge feature near about 2149.0 eV is observed in NIST 2781 and is consistent with minor Fe-P complexation; in certain embodiments this feature is absent in EWAS and WAS, indicating a lack of detectable Fe complexation in those materials. A shoulder near about 2162 eV is indicative of struvite (NH4MgPO4-6H2O), and, together with an oxygen oscillation feature near about 2170.0 eV, forms a characteristic doublet observed across the spectra.

[0146] Phosphorus can be, in certain embodiments, limiting for root development and photosynthesis because native soil P is often present in sparingly soluble forms (e.g., Fe- or Al-Attorney Docket No.: 072253-92000 associated phases). In alkaline to neutral systems, inorganic P tends to occur as calcium phosphates that are comparatively stable at the pH values evaluated. When soluble phosphate is introduced to alkaline soils, H2PO4 can react with Ca to form phases of decreasing aqueous solubility (e.g., monocalcium, dicalcium, and tricalcium phosphates). In the disclosed experiments, high levels of phosphorus removal from solution are observed across treatments and, in some embodiments, are attributed to precipitation or transformation to low-solubility calcium-phosphate compounds and / or sorption to soil surfaces. Calcium can be supplied by a background electrolyte and / or by calcareous soil minerals (e.g., CaCCh). In addition, fixation of phosphate by clay minerals can occur over a wide pH range and may be enhanced where clay surfaces are coated with iron oxides that present positively charged sites for phosphate adsorption.

[0147] FIG. 10 illustrates, in certain embodiments, the percentage of phosphorus sorbed in agricultural-soil and potting-mix systems based on reaction filtrates. As used herein, the percentage sorbed can be determined by subtracting phosphorus released by soil-only controls from phosphorus released by the sample and normalizing by phosphorus released by fertilizer- only controls. In representative results, slightly lower apparent P sorption is observed for systems amended with an inorganic fertilizer formulated with a highly soluble phosphate source (e.g., diammonium phosphate). In some embodiments, this high solubility reduces, but does not eliminate, sorption, with on the order of about 90% of phosphorus still removed from solution. Competitive adsorption by sulfate (e.g., from ammonium sulfate) can further influence phosphate partitioning by occupying positively charged binding sites. Reaction time, in certain embodiments, does not materially affect phosphorus sorption, consistent with rapid complexation / precipitation kinetics in the presence of calcium and reactive soil surfaces.

[0148] With respect to EWAS- and WAS-amended systems, the high fraction of phosphorus removed from solution has favorable implications for minimizing off-site transport. In someAttorney Docket No.: 072253-92000 embodiments, the low concentration of soluble P remaining in solution is expected to reduce runoff and leaching potential in the field, thereby benefiting water quality. Sorbed phosphorus can, in certain embodiments, desorb gradually, supporting characterization of EWAS as a slow- release nutrient source.

[0149] In some embodiments, EWAS- and WAS-amended samples release less total nitrogen to solution than other fertilizer treatments as a consequence of adsorption of nitrogencontaining biomolecules to clay minerals. Such adsorption protects organic nitrogen from rapid microbial degradation while preserving biological functionality. Electrochemical treatment of WAS to produce EWAS can slightly increase nitrogen solubility without altering aqueous- phase speciation, and EWAS-amended systems can exhibit reduced ammonium adsorption, consistent with electrochemically induced modification of organic-matter binding sites. EWAS-amended samples, in certain embodiments, release greater amounts of organic and total carbon to solution than other treatments, which is consistent with alkaline electrochemical disruption of organic-matter structure and suggests enhanced availability of soluble carbon to support microbial biodiversity and improved soil structure. Organic-carbon surface coatings associated with EWAS and WAS can inhibit potassium diffusion from clay interlayers, and phosphorus in EWAS and WAS solids is identified as struvite by XANES. When considered together, these findings support use of EWAS as a slow-release fertilizer capable of reducing nutrient losses and advancing circular nutrient management. Further work can include expanded solid-phase characterization, advanced spectroscopic analyses, and microbial community assessments to refine agronomic and environmental performance predictions.

[0150] In certain working examples, sandy-loam field soils were collected and placed into greenhouse pots. Five treatments were applied at a constant nitrogen rate of approximately 70 lb N per acre: (i) electrochemically treated waste activated sludge (EWAS) in accordance with the present disclosure; (ii) untreated waste activated sludge (WAS); (iii) a commerciallyAttorney Docket No.: 072253-92000 available composted municipal biosolid (e.g., DilloDirt); (iv) an inorganic nutrient solution; and (v) an unamended control. Wheat e.g., cultivar TAM 204) was grown for about 120 days. Measurements included, in various embodiments, plant root and shoot biomass, grain yield, microbial biomass carbon, and soil nutrient pools (C, N, P).

[0151] FIGS. 11 A-l IB depict, in certain embodiments, plant tissue weights obtained under the foregoing treatments. In representative results, plots amended with EWAS exhibited greater plant growth than comparator treatments when assessed by shoot dry weight, root dry weight, and total biomass.

[0152] FIG. 12 illustrates, in some embodiments, microbial biomass carbon for control, inorganic nutrient solution, composted biosolids, WAS, and the EWAS product of the present disclosure. In representative evaluations, EWAS stimulated microbial biomass to levels characteristic of compost-amended systems and greater than those observed with inorganic fertilizer alone, indicating improvements in soil biological health consistent with organic- residue amendments.

[0153] As shown in Table 7 below, in certain embodiments, treatment performance was also assessed in terms of agronomic efficiency and nutrient recovery.Treatment Nitrogen Agronomic Phosphorus RecoveryEffi ci ency of Pl ant (%) Effi ci ency of Pl ant (%)Present Disclosure 7.10 ±1.08 3.09 ± 0.32(E-GROW and / orEGR0W-AD±)Inorganic Fertilizer 5.99 ±1.20 3.46 ± 0.50Composted Biosolids 3.46 ±0.76 1.39 ± 0.39(Dillodirt)Untreated WAS 3.65 ±1.15 2.51 ± 0.54

[0154] By way of example, the EWAS treatment exhibited a nitrogen agronomic efficiency of about 7.10 ± 1.08% and a phosphorus recovery efficiency of about 3.09 ± 0.32%. ForAttorney Docket No.: 072253-92000 comparison, an inorganic fertilizer exhibited about 5.99 ± 1.20% nitrogen agronomic efficiency and about 3.46 ± 0.50% phosphorus recovery; a composted biosolid exhibited about 3.46 ± 0.76% nitrogen agronomic efficiency and about 1.39 ± 0.39% phosphorus recovery; and untreated WAS exhibited about 3.65 ± 1.15% nitrogen agronomic efficiency and about 2.51 ± 0.54% phosphorus recovery. These results indicate, in certain embodiments, that EWAS provides improved nitrogen use efficiency relative to inorganic fertilizer, composted biosolids, and untreated WAS, while achieving phosphorus recovery that is comparable to inorganic fertilizer and greater than composted biosolids and untreated WAS.

[0155] In additional embodiments, the EWAS production process demonstrates scalability using electrodes while maintaining compliance with applicable federal biosolids regulations, including pathogen reduction, vector attraction reduction (VAR), and metals criteria. The disclosed electrochemical configuration further shows, in certain evaluations, potential to reduce concentrations of perfluoroalkyl substances such as PFOA, PFHxA, and PFBS. Preliminary data also indicate potential for carbon sequestration or storage associated with EWAS production and / or soil application.

[0156] While embodiments of the invention have been shown and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings of the invention. The embodiments described and the examples provided herein are exemplary only, and are not intended to be limiting. Many variations and modifications of the invention disclosed herein are possible and are within the scope of the invention. The scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.

[0157] The disclosures of all patents, patent applications, and publications cited herein are hereby incorporated herein by reference in their entirety, to the extent that they provide exemplary, procedural, or other details supplementary to those set forth herein.Attorney Docket No.: 072253-92000

[0158] Amounts and other numerical data may be presented herein in a range format. It is to be understood that such range format is used merely for convenience and brevity and should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a numerical range of approximately 1 to approximately 4.5 should be interpreted to include not only the explicitly recited limits of 1 to approximately 4.5, but also to include individual numerals such as 2, 3, 4, and sub-ranges such as 1 to 3, 2 to 4, etc. The same principle applies to ranges reciting only one numerical value, such as “less than approximately 4.5,” which should be interpreted to include all of the above-recited values and ranges. Further, such an interpretation should apply regardless of the breadth of the range or the characteristic being described.

[0159] Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which the presently disclosed subject matter belongs. Although any methods, devices, and materials similar or equivalent to those described herein can be used in the practice or testing of the presently disclosed subject matter, representative methods, devices, and materials are now described.

[0160] Following long-standing patent law convention, the terms “a” and “an” mean “one or more” when used in this application, including the claims.

[0161] Unless otherwise indicated, all numbers expressing quantities of ingredients, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the presently disclosed subject matter.Attorney Docket No.: 072253-92000

[0162] As used herein, the term “about” and “substantially” when referring to a value or to an amount of mass, weight, time, volume, concentration or percentage is meant to encompass variations of in some embodiments ±20%, in some embodiments ±10%, in some embodiments ±5%, in some embodiments ±1%, in some embodiments ±0.5%, and in some embodiments ±0.1% from the specified amount, as such variations are appropriate to perform the disclosed method.

[0163] As used herein, the term “substantially perpendicular” and “substantially parallel” is meant to encompass variations of in some embodiments within ±10° of the perpendicular and parallel directions, respectively, in some embodiments within ±5° of the perpendicular and parallel directions, respectively, in some embodiments within ±1° of the perpendicular and parallel directions, respectively, and in some embodiments within ±0.5° of the perpendicular and parallel directions, respectively.

[0164] As used herein, the term “and / or” when used in the context of a listing of entities, refers to the entities being present singly or in combination. Thus, for example, the phrase “A, B, C, and / or D” includes A, B, C, and D individually, but also includes any and all combinations and subcombinations of A, B, C, and D.REFERENCES

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Claims

Attorney Docket No.: 072253-92000WHAT IS CLAIMED IS:

1. A method for enhancing nutrient mobility in soil, the method comprising:(a) providing waste, wherein the waste comprises one or more of waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof;(b) preparing an alkaline electrolyte solution;(c) subjecting the waste to electrolysis in the alkaline electrolyte solution using a pair of electrodes positioned operated at a cell potential of approximately ±2.5 volts, thereby producing an organic mineral fertilizer formulation; and(d) applying the organic mineral fertilizer formulation to a soil system at a rate of approximately 70 pounds nitrogen per acre, wherein the organic mineral fertilizer formulations comprises ammonium (NHL), nitrate (NCh ), and phosphorus.

2. The method of Claim 1, wherein the organic mineral fertilizer formulation is produced resultant from the electrochemical treatment of waste in the alkaline solution.

3. The method of Claim 2, wherein the electrochemical treatment comprises using sodium hydroxide as an electrolyte.

4. The method of Claim 2, wherein the electrochemical treatment is performed with the electrodes in a serpentine flow cell.

5. The method of Claim 2, wherein the electrochemical treatment releases the ammonium (NH4+) and the nitrate (NO3 ) into the organic mineral fertilizer formulation.Attorney Docket No.: 072253-920006. The method of Claim 1, wherein the organic mineral fertilizer formulation promotes slow-release of nitrogen into the soil system.

7. The method of Claim 1, wherein the organic mineral fertilizer formulation increases dissolved organic carbon (DOC) in the soil system.

8. The method of Claim 7, wherein the increased dissolved organic carbon promotes microbial biodiversity in the soil.

9. The method of Claim 1, wherein the phosphorus is in a form of struvite.

10. The method of Claim 9, wherein the phosphorus is further complexed with calciumphosphate compounds.

11. The method of Claim 1, wherein the soil system comprises agricultural soil, potting mix, or combinations thereof.

12. The method of Claim 11, wherein the agricultural soil is calcareous soil.

13. The method of Claim 1, wherein the organic mineral fertilizer formulation reduces nitrogen runoff compared to traditional fertilizers.

14. The method of Claim 1, wherein the organic mineral fertilizer formulation is introduced upstream of an anaerobic digester to increase biogas production while maintaining the nutrient profile of the formulation.Attorney Docket No.: 072253-9200015. The method of Claim 14, wherein the organic mineral fertilizer formulation has a moisture content between approximately 60 percent and 90 percent at the point of introduction upstream of the anaerobic digester.

16. The method of Claim 14, wherein the introduction of the organic mineral fertilizer formulation upstream of the anaerobic digester increases methane generation by at least 10 percent relative to untreated sludge.

17. The method of Claim 14, wherein the electrochemical treatment used to produce the organic mineral fertilizer formulation comprises using an alkaline electrolyte comprising potassium hydroxide (KOH), calcium oxide (CaO), calcium hydroxide (Ca(OH)2), iron sulfate, or combinations thereof.

18. The method of Claim 1, wherein the organic mineral fertilizer formulation further comprises long-chain fatty acids (LCFAs) functioning as structural agents to reduce volatilization and enhance soil retention.

19. The method of Claim 1, wherein the organic mineral fertilizer formulation further comprises short-chain fatty acids (SCFAs) and volatile fatty acids (VFAs) that promote microbial activity and act as bio-stimulants.

20. The method of Claim 1, wherein the organic mineral fertilizer formulation is pathogen- reduced and stable against release of methane, volatile organic compounds, ammonia, or nitrous oxide.Attorney Docket No.: 072253-9200021. A system for producing and applying an organic mineral fertilizer formulation to soil, the system comprising:(a) an electrochemical treatment unit comprising:(i) a reaction chamber configured as a serpentine flow cell;(ii) a pair of electrodes disposed within the reaction chamber;(iii) an alkaline electrolyte reservoir containing an alkaline solution;(iv) a power supply operatively coupled to the electrodes and configured to apply a cell potential of approximately ±2.5 volts in an electrolysis process; and(v) a sludge inlet and outlet permitting the passage of waste through the reaction chamber during electrolysis to produce the organic mineral fertilizer formulation, wherein the waste comprises one or more of waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof; and(b) a soil distribution apparatus comprising:(i) a storage tank for receiving the organic mineral fertilizer formulation from the outlet of the reaction chamber; and(ii) a delivery manifold connected to the storage tank and configured to apply the organic mineral fertilizer formulation to a soil system at a rate of 70 pounds nitrogen per acre.

22. The system of Claim 21, wherein the electrodes comprise one or more of nickel, copper, cobalt, chromium, stainless steel, silver, gold, transition metals, or combinations thereof.Attorney Docket No.: 072253-9200023. The system of Claim 21, wherein the electrochemical cell uses sodium hydroxide as an electrolyte to perform the electrochemical treatment of the WAS, biosolids, manure, food waste, or combinations thereof.

24. The system of Claim 21, wherein the electrochemical cell uses polarity switching during the electrolysis process.

25. The system of Claim 21 , wherein the electrochemical cell reduces pathogen content and increases bioavailable nutrients in the organic mineral fertilizer formulation.

26. The system of Claim 21, wherein the soil distribution apparatus evenly applies organic mineral fertilizer formulation to the soil system at the rate of approximately 70 pounds nitrogen per acre.

27. The system of Claim 21, wherein the system further comprises an anaerobic digester fluidly coupled upstream of the electrochemical treatment unit.

28. The system of Claim 27, wherein the organic mineral fertilizer formulation has a moisture content between about 60 percent and 90 percent at the point of introduction upstream of the anaerobic digester.

29. The system of Claim 27, wherein the electrochemical treatment unit and the anaerobic digester are integrated within a closed-loop processing line configured to reduce emissions of methane, ammonia, and volatile organic compounds during operation.Attorney Docket No.: 072253-9200030. The system of Claim 21, wherein the electrochemical treatment unit comprises an alkaline electrolyte selected from potassium hydroxide (KOH), calcium oxide (CaO), calcium hydroxide (Ca(OH)2), iron sulfate, or combinations thereof.

31. A fertilizer composition comprising:(a) an organic mineral matrix produced by electrochemical treatment of waste, wherein the waste comprises one or more of waste activated sludge (WAS), biosolids, manure, food waste, or combinations thereof;(b) a nutrient fraction comprising nitrogen, phosphorus, carbon, and sulfur; and(c) micronutrients selected from potassium (K), iron (Fe), calcium (Ca), or combinations thereof, wherein the fertilizer composition is configured to provide controlled release of the nutrient fraction upon application to soil.

32. The fertilizer composition of Claim 31, wherein the phosphorus comprises struvite.

33. The fertilizer composition of Claim 32, wherein the phosphorus is further present as calcium-phosphate complexes.

34. The fertilizer composition of Claim 31, wherein the nitrogen comprises ammonium (NH4) and nitrate (NCh ).

35. The fertilizer composition of Claim 31, wherein the fertilizer composition further comprises long-chain fatty acids (LCFAs) functioning as structural agents to reduce volatilization and enhance soil retention.Attorney Docket No.: 072253-9200036. The fertilizer composition of Claim 31, wherein the fertilizer composition further comprises short-chain fatty acids (SCFAs) and volatile fatty acids (VFAs) that promote microbial activity and act as bio-stimulants.

37. The fertilizer composition of Claim 31, wherein the organic mineral matrix is produced using an alkaline electrolyte comprising potassium hydroxide (KOH), calcium oxide (CaO), calcium hydroxide (Ca(OH)2), iron sulfate, or combinations thereof.

38. The fertilizer composition of Claim 31, wherein the fertilizer composition is formulated for introduction upstream of an anaerobic digester to increase biogas production while preserving the nutrient profile of the fertilizer composition.

39. The fertilizer composition of Claim 38, wherein the fertilizer composition has a moisture content between about 60 percent and about 90 percent at the point of introduction upstream of the anaerobic digester.

40. The fertilizer composition of Claim 31, wherein the fertilizer composition is pathogen- reduced and stable against release of methane, volatile organic compounds, ammonia, or nitrous oxide during storage.

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