Removing materials from water

Abstract

Various embodiments relate to a method and system for removing phosphorus and / or nitrogen from water. A method for removing phosphorus and nitrogen from water includes passing a starting raw water containing nitrogen and phosphorus through a phosphorus removal section at an elevated pH. The method includes passing the water through an electrolytic nitrogen removal section. The method includes passing the water through a galvanic phosphorus removal section. The water produced by the method has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw water.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 62 / 860,433, filed on June 12, 2019, the disclosure of which is incorporated herein by reference in its entirety. Background Art

[0003] Phosphorus is a common component of agricultural fertilizers, manure, and organic waste in sewage and industrial effluents. It is essential for plant life, and when too much is present in water, it can lead to plant and algae growth and consume oxygen in the water at a rate beyond what the ecosystem can handle, with potentially severe ecological impacts, including toxic algal blooms, die-offs of native aquatic species, and loss of biodiversity (eutrophication). While a variety of methods are available to remove phosphorus from water, existing methods can be expensive, inconvenient, inefficient, lack scalability, or may not be environmentally friendly.

[0004] Nitrogen is a common component of agricultural fertilizers, manure, and organic waste in sewage and industrial wastewater. It is an essential element for plant life. However, when there is too much nitrogen in water, it causes the growth of plants and algae and can consume oxygen in the water at a rate faster than the ecosystem can handle, causing serious ecological impacts, including toxic algal blooms, die-offs of native aquatic species, and loss of biodiversity (eutrophication). Simple particle removal methods such as filtration will remove particles and reduce total nitrogen concentrations; however, these methods will not reduce the concentration of water-soluble forms of nitrogen. Although a variety of methods are available to remove soluble nitrogen from water, these methods are expensive, complex, and difficult to control. Summary of the invention

[0005] In various embodiments, the present invention provides a method for removing phosphorus and nitrogen from water. The method includes passing a starting raw water containing nitrogen and phosphorus through a phosphorus removal stage with an increased pH. The phosphorus removal stage with an increased pH includes raising the pH of the water to greater than or equal to 7.5 to precipitate phosphorus salts from the water. The phosphorus removal stage with an increased pH also includes removing precipitated phosphorus salts from the water. The method includes passing the water through an electrolytic denitrification stage, which includes passing the water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas. The method also includes passing the water through a galvanic dephosphorization stage, which includes immersing a galvanic cell in water to form treated water containing salts, the salts containing phosphorus from the water. The galvanic cell includes an anode, which includes Mg, Al, Fe, Zn, or a combination thereof; and a cathode having a different composition from the anode, which includes Cu, Ni, Fe, or a combination thereof. The galvanic dephosphorization stage also includes separating phosphorus-containing salts from the treated water. The water produced by this method has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw water.

[0006] In various embodiments, the present invention provides a method for removing phosphorus and nitrogen from water. The method includes passing a starting raw material water containing nitrogen and phosphorus through a phosphorus removal section with an increased pH. The phosphorus removal section with an increased pH includes using one or more bases to raise the pH of the water to 8.5 to 9.5 to precipitate phosphate salts from the water, the phosphate salts including magnesium ammonium phosphate, calcium phosphate, or a combination thereof. The phosphorus removal section with an increased pH also includes removing the precipitated phosphate salts from the water. The phosphorus removal section with an increased pH removes 90-98% of the active phosphorus in the water. The method includes passing the water through an electrolytic denitrification section, which includes passing the water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas. The electrolytic cell includes a cathode comprising stainless steel and an anode comprising titanium oxide, ruthenium oxide, and iridium oxide (TiO2-RuO2-IrO2 / Ti) supported on titanium. Passing the water through the electrolytic denitrification section can remove 80-100% of ammonia from the water. The method also includes passing the water through a galvanic dephosphorization section, which includes immersing a galvanic cell in water to form treated water containing a salt, the salt containing phosphorus from the water. The salt includes AlPO4 or a hydrate thereof, the AlPO4 containing phosphorus and Al from the anode; aluminum hydroxide or a hydrate thereof, the aluminum hydroxide containing Al from the anode; or a combination thereof. The galvanic cell includes an anode containing Al, wherein the anode is about 90% to about 100% by weight Al. The galvanic cell includes a cathode containing Cu, wherein the cathode is about 90% to about 100% by weight Cu. The galvanic cell also includes a conductive connector electrically connecting the anode and the cathode, the conductive connector including an alloy containing Cu and Zn. The galvanic dephosphorization section also includes separating phosphorus-containing salts from the treated water. The water produced by this method has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw water. The water produced by this method has a total phosphorus concentration of about 0.0001ppm to 0.05ppm, and a total nitrogen concentration of about 0ppm to about 1ppm.

[0007] In various embodiments, the present invention provides a method for removing nitrogen from water. The method includes passing water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas.

[0008] In various embodiments, the present invention provides a method for removing nitrogen from water. The method comprises passing water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas. The electrolytic cell comprises a cathode comprising stainless steel; and an anode comprising: titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti), or titanium oxide and ruthenium oxide supported on titanium (TiO2-RuO2 / Ti), or titanium and platinum (Ti-Pt), or a combination thereof. Removing nitrogen in the form of nitrogen gas removes 80-100% of ammonia from water.

[0009] In various embodiments, the present invention provides a system for removing nitrogen and phosphorus from water. The system includes a phosphorus removal section that increases the pH of the starting raw water to greater than or equal to 7.5 to precipitate phosphorus salts from the water and is configured to remove the precipitated phosphorus salts from the water. The system includes an electrolytic denitrification section, which includes an electrolytic cell configured to remove nitrogen from water in the form of nitrogen gas. The system includes a galvanic dephosphorization section, which includes a galvanic dephosphorization section, which includes a galvanic cell, which includes an anode, which includes Mg, Al, Fe, Zn or a combination thereof; and a cathode having a different composition from the anode, which includes Cu, Ni, Fe or a combination thereof; The galvanic cell is configured to form treated water containing salts, which contain phosphorus from the water, wherein the galvanic dephosphorization section is configured to separate phosphorus-containing salts from the treated water. The water produced by the system has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw water.

[0010] In various embodiments, the present invention provides an apparatus for removing nitrogen from water. The apparatus includes an electrolytic cell through which water is configured to flow to remove nitrogen from the water in the form of nitrogen gas. The electrolytic cell includes a cathode comprising stainless steel and / or titanium; and an anode comprising: titanium oxide, ruthenium oxide, and iridium oxide (TiO2-RuO2-IrO2 / Ti) supported on titanium, or titanium oxide and ruthenium oxide (TiO2-RuO2 / Ti) supported on titanium, or titanium and platinum (Ti-Pt), or a combination thereof. Removing nitrogen in the form of nitrogen gas can remove 80-100% of ammonia from water.

[0011] In various embodiments, the phosphorus removal and / or nitrogen removal methods of the present invention have certain advantages over other methods of removing phosphorus from water. For example, in some embodiments, the phosphorus removal and / or nitrogen removal methods of the present invention can remove larger amounts of phosphorus and / or nitrogen, achieve lower phosphorus and / or nitrogen concentrations, achieve phosphorus and / or nitrogen removal with higher efficiency or lower cost, utilize a smaller footprint, or a combination of these advantages compared to other methods.

[0012] In various embodiments, the phosphorus and / or nitrogen removal methods of the present invention can be performed with less oxidizing influent water than other methods, or with non-oxidizing influent water. In some embodiments comprising a galvanic cell comprising an anode comprising Al, the higher pH near the anode caused by the generation of hydroxide ions can induce or enhance the precipitation of aluminum salts (e.g., AlPO4, aluminum hydroxide, or a combination thereof). In some embodiments, the ratio of Al to P for removing phosphorus from water is lower than those reported by other methods, such as methods using the addition of aluminum salts. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The drawings generally illustrate various embodiments of the invention by way of example and not limitation.

[0014] Figure 1A A view of an electrochemical cell from a major side is shown according to various embodiments.

[0015] Figure 1B An enlarged cross-sectional edge view of an electrochemical cell according to various embodiments is shown.

[0016] Figure 2A Shown are photographs along the edge of an Al-Cu electrochemical cell according to various embodiments.

[0017] Figure 2B Shown are photographs along the edges of multiple Al-Cu electrochemical cells according to various embodiments.

[0018] Figure 2C Shown are photographs of major surfaces of Mg-Cu electrochemical cells according to various embodiments.

[0019] Figure 2D Shown is a photograph of the edge of a Mg-Cu electrochemical cell according to various embodiments.

[0020] Figure 2E Shown is a photograph of the edge of a Mg-Cu electrochemical cell according to various embodiments.

[0021] Figure 2F Photographs showing a top view of a system for removing material from water according to various embodiments are shown.

[0022] Figure 2G A photograph showing a side view of a system for removing material from water according to various embodiments is shown.

[0023] Figure 3 The current produced by an Al-Cu cell versus time for solutions having various conductivities is shown according to various embodiments.

[0024] Figure 4 The current produced by an Al-Cu cell versus time for solutions having various pH levels according to various embodiments is shown.

[0025] Figure 5A The current produced by a Mg-Cu cell versus time for solutions having various conductivities is shown according to various embodiments.

[0026] Figure 5B The current produced by a Mg-Cu cell versus time for solutions having various pH levels according to various embodiments is shown. DETAILED DESCRIPTION

[0027] Reference will now be made in detail to certain embodiments of the disclosed subject matter.While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the illustrated subject matter is not intended to limit the claims to the disclosed subject matter.

[0028] In this document, values ​​expressed in range format should be interpreted in a flexible manner to include not only the values ​​explicitly cited as range limits, but also all individual values ​​or sub-ranges contained within the range, as if each value and sub-range were explicitly stated. For example, a range of "about 0.1% to about 5%" or "about 0.1% to 5%" should be interpreted as including not only about 0.1% to about 5%, but also individual values ​​(e.g., 1%, 2%, 3% and 4%) and sub-ranges within the specified range (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%). Unless otherwise specified, a statement of "about X to Y" has the same meaning as "about X to about Y". Similarly, unless otherwise specified, a statement of "about X, Y or about Z" has the same meaning as "about X, about Y or about Z".

[0029] In this document, unless the context clearly dictates otherwise, the terms "a", "an", or "the" are used to include one or more than one. Unless otherwise specified, the term "or" is used to refer to a non-exclusive "or". The statement "at least one of A and B" or "at least one of A or B" has the same meaning as "A, B, or A and B". In addition, it should be understood that the words or terms used herein and not otherwise defined are for descriptive purposes only and not for limiting purposes. The use of any section headings is intended to aid in reading the document and should not be construed as limiting; information related to the section heading may appear inside or outside that particular section.

[0030] In the methods described herein, except where time or order of operations is explicitly stated, the actions may be performed in any order without departing from the principles of the invention. In addition, specified actions may be performed simultaneously unless explicit claim language states that they are performed separately. For example, a claimed action to perform X and a claimed action to perform Y may be performed simultaneously in a single operation, and the resulting process would fall within the literal scope of the claimed process.

[0031] As used herein, the term "about" can allow for a certain degree of variability within a value or range, such as within 10%, 5% or 1% of a specified value or specified limit, and includes the exact specified value or range. As used herein, the term "substantially" refers to a majority or a large portion, such as at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%. As used herein, the term "substantially free" can mean having no or insignificant amounts such that the amount of material present does not affect the material properties of the composition containing the material, such that from about 0 weight percent to about 5 weight percent of the composition is the material, or from about 0 weight percent to about 1 weight percent, or about 5 weight percent or less, or less than or equal to about 4.5 weight percent, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01, or about 0.001 weight percent or less, or about 0 weight percent of the composition is the material.

[0032] In various embodiments, the salt with a positively charged counterion can include any suitable positively charged counterion. For example, the counterion can be ammonium NH4 + ), or sodium (Na + ), potassium (K + ) or lithium (Li + In some embodiments, the counterion may have a positive charge greater than +1, which in some embodiments may be combined with a multiply ionizable group (e.g., Zn 2+ 、Al 3+ ) or such as Ca 2+ or Mg 2+ Alkaline earth metal complex.

[0033] Unless otherwise stated, all concentrations of phosphorus, nitrogen, chlorine, ammonia, magnesium and aluminum mentioned are dissolved concentrations of these materials in elemental or non-elemental form (e.g., in the form of compounds or ions containing the materials). Unless otherwise stated, all concentrations given herein are by weight.

[0034] Unless otherwise indicated, as used herein, "total phosphorus concentration" refers to the concentration of all forms of phosphorus as measured by US-EPA 365.1: Determination of Phosphorus by Semi-Automated Colorimetry or an equivalent method.

[0035] Unless otherwise indicated, as used herein, "dissolved phosphorus concentration" refers to the concentration of all forms of phosphorus that can pass through a 0.45 micron filter and as measured by US-EPA 365.1: Semi-Automated Colorimetric Determination of Phosphorus or an equivalent method.

[0036] Unless otherwise indicated, as used herein, "active phosphorus concentration" refers to the soluble active phosphorus (eg, orthophosphate) in solution as measured by US-EPA 365.1: Semi-Automated Colorimetric Determination of Phosphorus or an equivalent method.

[0037] Methods for removing phosphorus and nitrogen from water.

[0038] Various embodiments of the present invention provide a method for removing phosphorus and nitrogen from water. The method may include passing a starting raw water containing nitrogen and phosphorus through a phosphorus removal section with an increased pH. The phosphorus removal section with an increased pH includes raising the pH of the water to greater than or equal to 7.5 to precipitate phosphorus salts from the water, and removing the precipitated phosphorus salts from the water. The method may include passing the water through an electrolytic denitrification section, which includes passing the water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas. The method may also include passing the water through a galvanic dephosphorization section, which includes immersing a galvanic cell in water to form treated water containing salts, the salts containing phosphorus from the water. The galvanic cell may include an anode containing Mg, Al, Fe, Zn, or a combination thereof; and a cathode having a different composition from the anode, the cathode containing Cu, Ni, Fe, or a combination thereof. The galvanic dephosphorization section may include separating phosphorus-containing salts from the treated water. The water produced by the method may have a lower phosphorus concentration and a lower nitrogen concentration (e.g., a lower dissolved phosphorus / nitrogen concentration) than the starting raw water.

[0039] Water can flow from the elevated pH phosphorus removal section to the electrolytic denitrification section. Water can flow from the electrolytic denitrification section to the galvanic dephosphorization section. The water produced by the galvanic dephosphorization section can be the final water product of the method, or water can flow from the galvanic dephosphorization section to an optional further denitrification section. The method can optionally include one or more intermediate steps between any one or more sections; in some embodiments, the method includes one or more intermediate steps, while in other embodiments, the method has no intermediate steps between the elevated pH phosphorus removal section and the electrolytic denitrification section, between the electrolytic denitrification section and the galvanic dephosphorization section, between the galvanic dephosphorization section and the optional further denitrification section, or a combination of these times.

[0040] The starting material water can be taken from any suitable source, such as a natural water source in the environment, drinking water (e.g., for removing magnesium ammonium phosphate to prevent formation in pipelines), industrial wastewater, industrial cooling water, or a combination thereof. The water can be water taken from a source including a natural water source in the environment (e.g., a pond, lake, river, stream, etc.). In some embodiments, the method may include taking water from the source, returning the water to the source after removing nitrogen and phosphorus, or a combination thereof. The starting material water can be a product of fertilizer production or mining. For example, the starting material water can be water taken from a phosphate ore reservoir, such as water derived from a process in which phosphate-containing rocks are dissolved to produce phosphoric acid.

[0041] The starting raw water can have any suitable pH, for example less than 7.5, or 1 to less than 7.5, or 2-6, 4-5, or 1 or greater but less than 7.5, or less than, equal to or greater than 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7 or a pH of 7.5 or less.

[0042] The phosphorus in the starting material water may be in any suitable form, such as elemental phosphorus, inorganic phosphorus, organic phosphorus, dissolved phosphorus, solid phosphorus, oxidized phosphorus, or a combination thereof.

[0043] The nitrogen in the water may be in any suitable form, such as elemental nitrogen, inorganic nitrogen, organic nitrogen, dissolved nitrogen, solid nitrogen, nitrogen oxides, or combinations thereof.

[0044] The starting feed water can have any suitable ammonia concentration, for example, 50 ppm to 5,000 ppm, 150 ppm to 400 ppm, or 50 ppm or more, or less than, equal to, or greater than 100 ppm, 150, 200, 250, 300, 350, 400, 450, 500, 600, 750, 1,000, 2,000, 3,000, 4,000, or 5,000 ppm or less.

[0045] The starting feed water can have any suitable active phosphorus concentration, for example, from 10 ppm to 10,000 ppm, from 50 ppm to 400 ppm, or 10 ppm or more, or less than, equal to, or greater than 25 ppm, 50, 100, 150, 200, 250, 300, 350, 400, 500, 750, 1,000, 2,000, 4,000, 6,000, 8,000, or 10,000 ppm or less.

[0046] The starting feed water can have any suitable sodium concentration, for example, from 50 ppm to 20,000 ppm, from 400 ppm to 5,000 ppm, or 50 ppm or more, or less than, equal to, or greater than 100 ppm, 200, 400, 600, 800, 1,000, 1,500, 2,000, 2,500, 3,000, 3,500, 4,000, 4,500, 5,000, 7,500, 10,000, 12,500, 15,000, 17,500, or 20,000 ppm or less.

[0047] The starting feed water can have any suitable magnesium concentration, for example, from 10 ppm to 10,000 ppm, from 50 ppm to 600 ppm, or 10 ppm or more, or less than, equal to, or greater than 50 ppm, 100, 200, 300, 400, 500, 600, 700, 800, 1,000, 2,000, 4,000, 6,000, 8,000, or 10,000 ppm or less.

[0048] The starting feed water can have any suitable chloride concentration, for example, 50 ppm to 40,000 ppm, 200 ppm to 10,000 ppm, or 50 ppm or more, or less than, equal to, or greater than 100 ppm, 200, 500, 1,000, 2,000, 4,000, 6,000, 8,000, 10,000, 15,000, 20,000, 30,000, or 40,000 ppm or less.

[0049] The water produced by the method can have a total phosphorus concentration, a dissolved phosphorus concentration, an active phosphorus concentration, or a combination thereof of about 0 ppm to about 1 ppm, about 0.0001 ppm to 0.1 ppm, about 0.0001 ppm to 0.05 ppm, or about 0 ppm, or less than, equal to, or greater than about 0.0001 ppm, 0.0002, 0.0004, 0.0006, 0.0008, 0.0010, 0.0012, 0.0014, 0.0015, 0.0016, 0.0017, 0.0018, 0.0019, 0.0110, 0.0121, 0.0130, 0.0141, 0.0153, 0.0164, 0.0165, 0.0166, 0.0167, 0.0168, 0.0169, 0.0171, 0.0173, 0.0174, 0.0175, 0.0176, 0.0177, 0.0178, 0.0179, 0.0181, 0.0183, 0.0184, 0.0185, 0.00186, 0.00187, 0.00188, 0.00189, 0.00190, 0 ppm or more. The water produced by the method may have a total phosphorus concentration, dissolved phosphorus concentration, active phosphorus concentration, or a combination thereof that is about 0% to 70% of the corresponding total phosphorus concentration, dissolved phosphorus concentration, active phosphorus concentration, or a combination thereof of the starting raw water, or about 0% to about 20%, or about 0%, or less than, equal to, or greater than about 0.001%, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or about 70% or more.

[0050] The water produced by the method can have any suitable total nitrogen concentration, dissolved nitrogen concentration, or combination thereof, such as 0 ppm to about 2 ppm, 0 ppm to about 1 ppm, or about 0 ppm, or less than, equal to, or greater than about 0.001 ppm, 0.0012, 0.0014, 0.0016, 0.0018, 0.0020, 0.0022, 0.0024, 0.0026, 0.0028 , 0.0030, 0.0032, 0.0034, 0.0036, 0.0038, 0.0040, 0.0045, 0.0050, 0.0060, 0.0080, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 1.1, 1.2, 1.4, 1.6, 1.8 or about 2 ppm or less. The water produced by the method may have a total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof that is from about 0% to 70%, or from about 0% to about 30%, or about 0%, or less than, equal to, or greater than about 0.001%, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or about 70% or more of the corresponding total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof of the starting raw water.

[0051] Phosphorus removal section with increased pH.

[0052] The method of removing phosphorus and nitrogen may include passing water through an elevated pH phosphorus removal section. The elevated pH phosphorus removal section includes raising the pH of the water to greater than or equal to 7.5 to precipitate phosphorus salts from the water, and removing the precipitated phosphorus salts from the water.

[0053] Raising the pH of water to precipitate phosphate salts from water may include raising the pH of water to any suitable level to induce precipitation of a suitable amount of phosphate salts. Raising the pH of water to precipitate phosphate salts may include raising the pH of water to 7.5 to 12, 8.5 to 9.5, or 7.5 or higher, or less than, equal to, or greater than 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, or 12 or less. Raising the pH of water to precipitate phosphate salts from water may include adding one or more bases to the water, such as any suitable one or more bases, such as NaOH, KOH, or a combination thereof. In various aspects, the method includes adding NaOH to the water, such as a 5% NaOH aqueous solution.

[0054] Precipitation can occur without the aid of other materials, or precipitation can occur in the presence of one or more added flocculants. The flocculant can be any suitable flocculant, such as anionic, cationic or nonionic flocculants, metal salt flocculants, starch-based flocculants, or combinations thereof. The flocculant can be an anionic polymer flocculant.

[0055] Removing the precipitated phosphate salts may be performed in any suitable manner so that the precipitate is separated from the water. Removing the precipitated phosphate salts from the water may include decantation, sedimentation, filtration or a combination thereof.

[0056] The precipitated phosphate salt may include any suitable one or more phosphate salts. The composition of the one or more precipitated phosphate salts may depend on the composition of the starting raw material water. The precipitated phosphate salt may include magnesium ammonium phosphate, calcium phosphate or a combination thereof.

[0057] The elevated pH phosphorus removal section can remove any suitable amount of phosphorus from the water. For example, the elevated pH phosphorus removal section can remove 70-100%, 90-98%, or 70% or more, or less than, equal to, or greater than 72%, 74, 76, 78, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, or 99.99% or less of the active phosphorus in the water.

[0058] The elevated phosphorus removal section may optionally remove ammonia from the water. The elevated phosphorus removal section may remove any suitable amount of ammonia from the water, such as 0-60%, 20-30%, or 0%, or less than, equal to, or greater than 10%, 20, 25, 30, 35, 40, 45, 50, 55, or 60% or less.

[0059] Electrolytic denitrification section.

[0060] The method of removing phosphorus and nitrogen may include passing water through an electrolytic denitrification section, which includes passing the water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas.

[0061] The electrolysis denitrification section may include passing water through an electrolytic cell or multiple electrolytic cells. Passing the water through the electrolytic cells may include allowing the water to contact the anode and cathode and may include allowing the water to pass between the anode and cathode. The electrolytic cells may be partially or completely submerged / immersed in the water. As the water passes through the electrolytic cells, shear may be applied to the water to increase exposure of the water to the cathode and anode surfaces.

[0062] Prior to passing through the electrolytic cell, the water can have any suitable chloride concentration, e.g., 50 ppm to 40,000 ppm, 200 ppm to 10,000 ppm, or 50 ppm or more, or less than, equal to, or greater than 100 ppm, 200, 500, 1,000, 2,000, 4,000, 6,000, 8,000, 10,000, 15,000, 20,000, 30,000, or 40,000 ppm or less.

[0063] The water in which the electrolytic cell is immersed can have any suitable pH, such as 6 to 12, 6 to 7, or 6 or more, or less than, equal to, or greater than 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, or 12 or less. The method may include adding one or more bases to the water to adjust or maintain the pH of the water, such as sodium hydroxide; in other embodiments, the method does not add an acid or base to the water to maintain or adjust its pH.

[0064] The electrolytic cell may be operated in any suitable manner to remove nitrogen from water in the form of nitrogen gas. The cell may be operated with direct current or alternating current. The electrolytic cell may be operated at any suitable current density, for example 0.001-0.1 A / cm 2 , 0.02-0.04A / cm2 or 0.001A / cm 2 or more, or less than, equal to, or greater than 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1 A / cm 2 or smaller.

[0065] The electrolytic cell includes an anode. The anode may comprise titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti); or titanium oxide and ruthenium oxide supported on titanium (TiO2-RuO2 / Ti); or titanium and platinum (Ti-Pt); or a combination thereof. The anode and cathode materials may be selected so that the electrodes facilitate the formation of chlorine gas to form hypochlorite during operation of the electrolytic cell.

[0066] The electrolytic cell includes a cathode. The cathode may comprise titanium, stainless steel, or a combination thereof. The cathode may comprise stainless steel.

[0067] The electrolytic cell can include a spacing between the anode and cathode of, for example, 0.5-8 mm, 2-4 mm, or 0.5 mm or more, or less than, equal to, or greater than 1 mm, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, or 8 mm or less.

[0068] The method is not limited to any particular mechanism for removing nitrogen from water in the form of ammonia using an electrolytic cell. Removing nitrogen in the form of nitrogen gas may include using an electrolytic cell to convert ammonia in the water into nitrogen gas. Passing the water through an electrolytic denitrification stage may produce hypochlorite in the water, which may react with ammonia in the water to form nitrogen gas, which may be released into the environment. The reaction may be carried out by NH4 + +1.5HOCl→0.5N2+1.5H2O+2.5H + The electrolytic cell may produce any suitable hypochlorite concentration in the water passing therethrough, such as 100-20,000 ppm hypochlorite, 2000-2500 ppm, or 100 ppm or greater, or less than, equal to, or greater than 200 ppm, 400, 600, 800, 1,000, 1,200, 1,400, 1,600, 1,800, 2,000, 2,100, 2,200, 2,300, 2,400, 2,500, 2,600, 2,800, 3,000, 4,000, 6,000, 8,000, 10,000, 15,000, or 20,000 ppm or less.

[0069] The electrolytic denitrification section can remove any suitable amount of nitrogen from the water. For example, passing the water through the electrolytic denitrification section can remove 80% to 100%, 99-100%, or 80% or more, or less than, equal to, or greater than 81%, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, 99.99, or 99.999% or less of ammonia from the water.

[0070] In various embodiments, the electrolytic denitrification section may further include removing phosphorus from the water, such as any suitable amount of phosphorus. For example, passing the water through the electrolytic denitrification section may remove 0.1% to 90% of the active phosphorus from the water, or 1-30%, or 0.1% or more, or less than, equal to, or greater than 2%, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 40, 50, 60, 70, 80, or 90% or less.

[0071] Galvanic phosphorus removal section.

[0072] The method of removing nitrogen and phosphorus may also include passing the water through a galvanic phosphorus removal section, which includes immersing a galvanic cell in water to form treated water containing a salt, the salt containing phosphorus from the water. The galvanic cell may include an anode containing Mg, Al, Fe, Zn, or a combination thereof; and a cathode having a different composition from the anode, the cathode containing Cu, Ni, Fe, or a combination thereof. The galvanic phosphorus removal section may include separating phosphorus-containing salts from the treated water. The galvanic phosphorus removal section does not apply a potential across the anode and cathode of the galvanic cell (e.g., a potential applied from a source other than the galvanic cell).

[0073] The galvanic dephosphorization section can reduce the total phosphorus concentration of the water, the dissolved phosphorus concentration of the water, the active phosphorus concentration of the water, the total nitrogen concentration of the water, the dissolved nitrogen concentration of the water, or a combination thereof by any suitable amount, for example, 70% to 100%, 80% to 100%, 90% to 100%, or 70% or more, or less than, equal to, or greater than 71%, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, 99.99, or 99.999% or less.

[0074] The water may have a total phosphorus concentration, a dissolved phosphorus concentration, an active phosphorus concentration, or a combination thereof of about 0.001 ppm to about 10,000 ppm, about 0.01 ppm to about 20 ppm, or about 0.001 ppm or less, or less than, equal to, or greater than about 0.005 ppm, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.15, 0.2, 0.4, 0.6, 0.8, 1, 2, 4, 6, 8, 10, 15, 20, 40, 60, 80, 100, 150, 200, 400, 600, 800, 1,000, 1,500, 2,000, 4,000, 6,000, 8,000, or about 10,000 ppm or more.

[0075] The water containing the phosphorus-containing salt separated therefrom may have a total phosphorus concentration, a dissolved phosphorus concentration, an active phosphorus concentration, or a combination thereof of about 0 ppm to about 1 ppm, about 0.0001 ppm to 0.1 ppm, about 0.0001 ppm to 0.05 ppm, or about 0 ppm, or less than, equal to, or greater than about 0.0001 ppm, 0.0002, 0.0004, 0.0006, 0.0008, 0.0010, 0.0012, 0.0014, 0.0015, 0.0016, 0.0017, 0.0018, 0.0019, 0.0110, 0.0121, 0.0130, 0.0141, 0.0152, 0.0163, 0.0174, 0.0175, 0.0186, 0.0197, 0.0218, 0.0220, 0.0231, 0.0243, 0.0250, 0.0261, 0.0271, 0.0273, 0.0280, 0.0291, 0.0313, 0.0324, 0.0335, 0.0346, 0.0357, 0.0368, 0.0370, 0.0381, 0.0392, 0.0413, 0.0434, 0.0443, 0 ppm or more. The water containing the phosphorus-containing salt separated therefrom may have a total phosphorus concentration, dissolved phosphorus concentration, active phosphorus concentration, or a combination thereof that is about 0% to 70%, or about 0% to about 20%, or about 0%, or less than, equal to, or greater than about 0.001%, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or about 70% or more of the corresponding total phosphorus concentration, dissolved phosphorus concentration, active phosphorus concentration, or a combination thereof of the water that initially contacted the galvanic cell.

[0076] During the immersion of the galvanic cell in the water, the water can have any suitable pH value. The pH can be about 2 to about 14, about 5 to about 11, about 5 to about 7, about 10 to about 11, or less than, equal to, or greater than about 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11, 11.5, 12, 12.5, 13, 13.5, or about 14 or more.

[0077] The galvanic dephosphorization stage may include adding an acid, a base, or a combination thereof to the water to adjust or control its pH. In some embodiments, the method does not add an acid, a base, or a combination thereof to the water. The acid, a base, or a combination thereof may be added to the water before the galvanic cell is immersed in the water, during the galvanic cell is immersed in the water, after the galvanic cell is immersed in the water, or a combination of these times.

[0078] The galvanic dephosphorization stage may include recirculating the water in which the galvanic cells are immersed so that the water contacts the galvanic cells multiple times. The water may be optionally filtered during the recirculation, for example to remove phosphorus-containing salts from the water.

[0079] Immersing the galvanic cell in water may form treated water comprising a phosphorus-containing salt. Contact between the water and the galvanic cell may result in the formation of a phosphorus-containing salt. At least some of the phosphorus-containing salt in the treated water may include solids. The formation of the phosphorus-containing solids may include precipitation, flocculation, or a combination thereof.

[0080] Separation of the phosphorus-containing salt from the treated water may be performed in any suitable manner. The separation may include decantation, sedimentation, filtration, or a combination thereof. The separation may include separating the treated water from the galvanic cell (e.g., removing the water that submerges the cell, which has been filtered or otherwise separated from the phosphorus-containing salt). Separation may occur during the recycling of the water back to the galvanic cell. Separation may be performed during contact of the galvanic cell with the water, such as by a filter that is immersed in the water and continuously filters the water during contact. Separation may occur after removing the water from the water that submerges the galvanic cell, such as by a filter on an outlet line outside the system. Filtering may be performed using a glass frit, a fabric filter, a paper filter, a disc filter, a rotary filter, a drum filter, a screen, a sieve, a granular filter medium, a filter aid, or a combination thereof. The separated water may optionally be further treated, such as by further contacting with the same or different galvanic cell, filtering, treating to remove one or more other non-phosphorus materials, performing pH adjustment, or a combination thereof.

[0081] The anode may be a sacrificial anode that is consumed during treatment of the water. The phosphorus-containing salt formed when the water contacts the galvanic cell may include material from the anode. The method may include forming a hydroxide salt including material from the anode during immersion of the galvanic cell in the water. Separating the phosphorus-containing salt from the treated water may further include separating the hydroxide salt including material from the anode from the treated water.

[0082] The method may include forming H2 and HO at the anode (e.g., on the surface of the anode, generated from the water) during immersion of the galvanic cell in the water. - The method may include forming H2 and HO at the cathode (e.g., on the surface of the cathode, generated from the water) during immersion of the galvanic cell in water. - The method may include forming H2O2, HO2 at the cathode (e.g., on the surface of the cathode) during immersion of the galvanic cell in water. -, or a combination thereof. The method may include applying shear to the water during immersion of the galvanic cell in water. The shear may be sufficient to expel at least some bubbles (e.g., including H2) from the surface of the anode, cathode, or a combination thereof. The shear may be sufficient to at least partially prevent or reduce oxide formation at the anode surface. The method may include applying a mechanical force, such as tapping, knocking, stirring, vibration, ultrasound, etc., to the galvanic cell immersed in water. The mechanical force may be sufficient to expel at least some bubbles including H2 from the surface of the anode, cathode, or a combination thereof; at least partially prevent oxide formation at the surface of the anode; at least partially prevent the phosphorus-containing salt from agglomerating on the surface of the anode; or a combination thereof.

[0083] The separated water may have a total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof that is between about 0% and 70%, or between about 0% and about 30%, or about 0%, or less than, equal to, or greater than about 0.001%, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, or about 70% or more of the corresponding total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof of the water.

[0084] The method may further include forming NH3, NH4 at the cathode (e.g., on the surface of the cathode) + , or a combination thereof, wherein NH3 and NH4 + The method may include forming a nitrogen-containing salt during immersion of the galvanic cell in water. Separating the phosphorus-containing salt from the treated water may include separating the nitrogen-containing salt from the treated water. The nitrogen-containing salt may include NH4MgPO4 or a hydrate thereof (e.g., magnesium ammonium phosphate).

[0085] The cathode of the galvanic cell may comprise Cu, Ni, Fe or a combination thereof, such as Cu or a Cu alloy. The cathode may be a solid material that is primarily Cu, Ni, Fe, their alloys or their combinations, or another material that is primarily coated with Cu, Ni, Fe, their alloys or their combinations. The cathode may be substantially free of materials other than Cu, Ni, Fe, their alloys or their combinations. The cathode may be about 50% by weight to about 100% by weight of Cu, Ni, Fe, their alloys or their combinations, about 90% by weight to about 100% by weight, or less than, equal to or greater than about 50% by weight, 55, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99 or about 99.999% by weight or more. In some embodiments, the cathode comprises Cu, and the anode comprises Mg. In some embodiments, the cathode comprises Cu, and the anode comprises Al.

[0086] The anode can be a solid material of approximately uniform composition, or can be a coating on another material. The anode has a composition different from that of the cathode. The anode can contain Mg, Al, Fe, Zn, or a combination thereof. The anode can include an alloy containing Mg, Al, Fe, Zn, or an alloy thereof. Mg, Al, Fe, Zn, an alloy thereof, or a combination thereof can be about 50% to about 100% by weight of the anode, or less than, equal to, or greater than about 50%, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, or about 99, 99.5, 99.9, 99.99, or about 99.999% by weight or more. The anode can be substantially free of materials other than Mg, Al, Fe, Zn, an alloy thereof, or a combination thereof.

[0087] The anode may further comprise Ag, Pt, Au, or a combination thereof. Ag, Pt, Au, or a combination thereof is about 0.0001 wt % to about 20 wt %, about 0.0001 wt % to about 5 wt %, or about 0 wt %, or about 0.0001 wt % or less, or 0.0002, 0.0004, 0.0006, 0.0008, 0.0010, 0.0012, 0.0014, 0.0016, 0.0018, 0.0020, 0.0022, 0.0024, 0.0026 %, 0.0028, 0.0030, 0.0032, 0.0034, 0.0036, 0.0038, 0.0040, 0.0045, 0.0050, 0.0060, 0.0080, 0.01, 0.02, 0.04, 0.06, 0.08, 0.1, 0.2, 0.4, 0.6, 0.8, 1, 1.5, 2, 4, 6, 8, 10, 12, 14, 16, 18 or about 20% by weight or more.

[0088] The anode may contain magnesium or a magnesium alloy. The anode may be substantially free of materials other than Mg or its alloy. The anode may be a magnesium alloy AZ91, which is about 90 wt % Mg, about 9 wt % Al, and about 1 wt % Zn. The anode may be about 50 wt % to about 100 wt % Mg or a Mg alloy, about 90 wt % to about 100 wt % Mg or a Mg alloy, or less than, equal to, or greater than about 50 wt %, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or about 99.999 wt % or more Mg or a Mg alloy. The phosphorus-containing salt may include magnesium phosphate, potassium magnesium phosphate (e.g., "K-struvite"), hydrates thereof, or combinations thereof, wherein the magnesium phosphate or potassium magnesium phosphate includes Mg from the anode. The magnesium phosphate may be in any suitable form, such as magnesium dihydrogen phosphate (Mg(H2PO4)2), dimagnesium phosphate (MgHPO4), trimagnesium phosphate (Mg3(PO4)2), hydrates thereof, or combinations thereof. Separating the phosphorus-containing salt from the treated water may include separating magnesium phosphate from the treated water. The water may further contain nitrogen, wherein the phosphorus-containing salt comprises NH4MgPO4 or a hydrate thereof (e.g., magnesium ammonium phosphate), wherein the NH4MgPO4 comprises phosphorus and Mg from the anode. The method may include forming Mg(OH)2 comprising Mg from the anode during immersion of the galvanic cell in water. Separating the phosphorus-containing salt from the treated water may include separating Mg(OH)2 from the treated water. During immersion of the galvanic cell in water, the water may have a pH of about 9.5 to about 11.5, or about 10 to about 11, or less than, equal to, or greater than 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, or about 11.5 or more. The method may include adjusting the rate at which fresh water is introduced into the galvanic cell so that the water in which the galvanic cell is immersed is maintained at a pH of about 9.5 to about 11.5, or about 10 to about 11, or less than, equal to, or greater than 9.5, 9.6, 9.7, 9.8, 9.9, 10.0, 10.1, 10.2, 10.3, 10.4, 10.5, 10.6, 10.7, 10.8, 10.9, 11.0, 11.1, 11.2, 11.3, 11.4, or about 11.5 or greater. The method may include immersing the galvanic cell in water until the water reaches a pH of about 9.5 to about 11.5, or about 10 to about 11, and then adjusting the rate at which fresh water is introduced into the galvanic cell so that the water in which the galvanic cell is immersed is maintained at a pH of about 9.5 to about 11.5, or about 10 to about 11.

[0089] The anode may contain Al. The anode may be substantially free of materials other than Al. The anode may be about 50 wt % to about 100 wt % Al, about 90 wt % to about 100 wt % Al, or less than, equal to, or greater than about 50 wt %, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or about 99.999 wt % or more Al. The phosphorus-containing salt may include AlPO4 or a hydrate thereof. Separating the phosphorus-containing salt from the treated water may include separating AlPO4 from the treated water. The method may include forming aluminum hydroxide or a hydrate thereof (e.g., Al(OH)3 or polyaluminum hydroxide) during immersion of the galvanic cell in water, the aluminum hydroxide comprising Al from the anode. Separating the phosphorus-containing salt from the treated water may include separating aluminum hydroxide from the treated water. During immersion of the galvanic cell in water, the water has a pH of about 4 to about 8, or about 5 to about 7, or about 4 or less, or about 4.2, 4.4, 4.6, 4.8, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.2, 7.4, 7.6, 7.8, or about 8 or more. The method may include adjusting the rate at which the acid is introduced into the water so that the water in which the galvanic cell is immersed is maintained at a pH of about 4 to about 8, or about 5 to about 7, or about 4 or less, or about 4.2, 4.4, 4.6, 4.8, 5, 5.1, 5.2, 5.3, 5.4, 5.5, 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.2, 7.4, 7.6, 7.8, or about 8 or more. The acid may be added to the water before the galvanic cell is immersed in the water, during the galvanic cell is immersed in the water, after the galvanic cell is immersed in the water, or a combination of the above times. The acid may be any suitable acid at any suitable concentration. The acid may include sulfuric acid, acetic acid, hydrochloric acid, or a combination thereof. The method may include flocculating aluminum-containing salts from the treated water.

[0090] The cathode may have a work function greater than the work function of the anode. For example, Cu has a work function of about 4.53-5.10 eV, Mg has a work function of about 3.66 eV, and Al has a work function of about 4.06-4.26 eV. The conductive connector may have a work function between the work function of the cathode and the work function of the cathode.

[0091] The galvanic cell may include a conductive connector that electrically connects the anode and the cathode. The conductive connector has a different composition than the anode or cathode. The conductive connector may be a solid material with a uniform composition, or may be a coating on another material. The conductive connector may contain Cu, Zn, Fe, Cd, Ni, Sn, Pb, or a combination thereof. The conductive connector may contain Cu. The conductive connector may contain Zn. The conductive connector may include an alloy containing Cu and Zn. The conductive connector may contain brass. The conductive connector may contain brass and may be substantially free of other materials. The conductive connector may be about 50% to about 100% brass by weight, about 90% to about 100% brass by weight, or less than, equal to, or greater than about 50%, 55, 60, 65, 70, 75, 80, 85, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or about 99.999% or more brass by weight.

[0092] During immersion of the galvanic cell in water, the water may have any suitable conductivity, such as from about 100 μS to about 1,000,000 μS, or from about 300 μS to about 100,000 μS, or from about 100 μS to about 1,200 μS, or less than, equal to, or greater than about 100 μS, 200, 300, 400, 500, 600, 700, 800, 900, 1 ,000, 1,100, 1,200, 1,500, 2,000, 4,000, 6,000, 10,000, 15,000, 20,000, 50,000, 100,000, 150,000, 200,000, 250,000, 500,000, 750,000 or about 1,000,000 μS or more. The method may not adjust the conductivity of the water. In some embodiments, the method includes adjusting the conductivity of the water so that the conductivity is maintained at about 100 μS to about 1,000,000 μS, or about 300 μS to about 100,000 μS, or about 100 μS to about 1,200 μS, or less than, equal to, or greater than about 100 μS, 200, 300, 400, 500, 600, 700, 800, 900, , 1,000, 1,100, 1,200, 1,500, 2,000, 4,000, 6,000, 10,000, 15,000, 20,000, 50,000, 100,000, 150,000, 200,000, 250,000, 500,000, 750,000, or about 1,000,000 μS or more. Adjusting the conductivity of the water may include adjusting the rate at which fresh water is introduced into the galvanic cell. Adjusting the conductivity of the water may include adding one or more salts to the water. The salt may be added to the water before the galvanic cell is immersed in the water, during the galvanic cell is immersed in the water, after the galvanic cell is immersed in the water, or a combination of these times. The one or more salts added to the water to adjust its conductivity may include a halogen salt, a sodium salt, a potassium salt, or a combination thereof. The one or more salts added to the water to adjust its conductivity may include sodium chloride.

[0093] When immersed in water, the galvanic cell can generate an electric current. The amount of current generated by the cell can be any suitable amount of current, such as about 0.001 mA / cm 2 to about 10mA / cm 2 , 0.01mA / cm 2 to about 0.5 mA / cm 2 , or less than, equal to, or greater than about 0.001 mA / cm 2, 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.5, 2, 2.5, 3, 4, 5, 6, 7, 8, 9 or about 10 mA / cm 2 or more.

[0094] Immersing the galvanic cell in water can be sufficient to oxidize the phosphorus in the water. The method can treat the water without using an oxidizing agent or an oxidizing treatment other than any oxidation that occurs due to immersing the galvanic cell in the water. In some embodiments, the method includes oxidizing the phosphorus in the water before immersing the galvanic cell in water, during immersing the galvanic cell in water, or a combination of these times. The method may include oxidizing the phosphorus in the water before immersing the galvanic cell in water. Oxidizing the phosphorus in the water may include contacting an oxidizing agent with the water to oxidize the phosphorus (e.g., to oxidize phosphorus in organic matter or solid matter containing phosphorus). An aqueous solution of the oxidizing agent may be added to the water. The aqueous solution of the oxidant has an oxidant concentration of about 0.001 ppm to about 999,999 ppm, about 50,000 ppm to about 140,000 ppm, or less than, equal to, or greater than about 0.001 ppm, 0.005, 0.01, 0.05, 0.1, 0.5, 1, 1.5, 2, 5, 10, 15, 20, 50, 100, 150, 200, 500, 1,000, 1, 100, 1,200, 1,500, 2,000, 2,500, 5,000, 10,000, 15,000, 20,000, 50,000, 100,000, 150,000, 200,000, 500,000, 750,000, or about 999,999 ppm or greater. The oxidant can be any suitable oxidant that oxidizes phosphorus. The oxidant can include ferrate, ozone, ferric chloride (FeCl3), potassium permanganate, potassium dichromate, potassium chlorate, potassium persulfate, sodium persulfate, perchloric acid, peracetic acid, potassium persulfate, hydrogen peroxide, sodium hypochlorite, potassium hypochlorite, hydroxides, sulfites, free radicals generated by their decomposition, or combinations thereof. Sufficient oxidant can be added, and sufficient treatment conditions used, such that the oxidant converts substantially all of the dissolved phosphorus in the water into an oxidized form of phosphorus.

[0095] Byproducts of the oxidation process may include negatively charged ionic compounds that readily accept electrons and are therefore preferentially reduced at the surface of the copper in the galvanic cell. Many of these compounds have very low regulatory limits, and a galvanic process may be used to remove or reduce the concentration of one or more of these highly regulated compounds prior to discharge or reuse of the treated water. Examples of the most common compounds that may be reduced or removed are chloramines, chlorates, perchlorates, bromates, hypochlorous acid, bleaching agents, etc., organic compounds, and combinations thereof. In addition, the galvanic process may reduce the oxygen level in the water to values ​​below 1 ppm, thereby creating attractive conditions for subsequent anoxic or anaerobic processes.

[0096] The method may not perform any steps to adjust the pH of the treated water. In some embodiments, the method may include adjusting the pH of the treated water to about 6 to 8, or about 7, or less than, equal to, or greater than about 6, 6.1, 6.2, 6.3, 6.4, 6.5, 6.6, 6.7, 6.8, 6.9, 7, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, or about 8 or greater.

[0097] The method may include immersing one or more of the galvanic cells in a housing containing the water. The method may include filtering the phosphorus-containing salts from the treated water through one or more filters at least partially immersed in the water in which the galvanic cells are immersed. The filter may include a glass frit, a fabric filter, a paper filter, a disc filter, a rotary filter, a drum filter, a screen, a sieve, a particulate filter medium, a filter aid, or a combination thereof. The filter may be a rotary disc filter. Filtering may include forming a filter cake on the filter, the filter cake including the phosphorus-containing salts. Filtering may include backwashing the filter to remove the filter cake from the filter and forming a backwash liquid including the removed filter cake. Any suitable water may be used to backwash the filter, such as using a portion of the water containing the precipitate to backwash the filter.

[0098] One or more galvanic cells may be located in water at a side of the housing, wherein the filter is located approximately in a center portion of the housing, in the water such that the filter is between the plurality of galvanic cells. The method may include using a plurality of filters. The plurality of filters may include a plurality of rotating disc filters.

[0099] The galvanic cell may include an anode comprising Mg, Al, Fe, Zn or a combination thereof. The galvanic cell may include a cathode comprising Cu, Ni, Fe or a combination thereof. The galvanic cell may also include a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof. In some embodiments, the anode and the cathode are in direct contact with each other and the electrochemical cell does not have a conductive connector, so that the electrode is in an "electroless" configuration. In an electroless configuration, a sacrificial anode material can be electrochemically plated or deposited on a non-sacrificial cathode material, thereby not requiring a conductive connector to electrically connect the anode and the cathode. An advantage of various embodiments of the electroless configuration is that less metallic copper can be used and the electrical drop between the electrodes can be reduced compared to a configuration including a conductive connector.

[0100] The primary cell may include a cathode, or multiple cathodes. The primary cell may include an anode, or multiple anodes. The electrochemical cell may not include a conductive connector, include a conductive connector, or multiple conductive connectors. The primary cell may include multiple conductive connectors, each of which independently electrically connects the anode and the cathode (e.g., in a parallel configuration rather than a series configuration). The multiple conductive connectors may be roughly evenly distributed around the periphery of the electrochemical cell. The conductive connector may include a connector or a fastener, such as a screw, a bolt, a nut, a washer, or a combination thereof.

[0101] The galvanic cell may have any suitable size or configuration such that the surface area of ​​the galvanic cell per unit volume of water containing phosphorus to be removed is sufficient to achieve phosphorus removal during the residence time of the water in the container. The galvanic cell may have any suitable total surface area per galvanic cell, or total anode surface area exposed to water per cell, such as about 1 cm 2 to about 1,000,000cm 2 、About 5cm 2 to about 200,000cm 2 , about 10cm2 to about 50,000cm 2 , about 20em 2 to about 40,000cm 2 or about 1cm 2 or smaller, or less than, equal to, or greater than 2 cm 2, 4, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 75, 100, 150, 200, 250, 500, 750, 1,000, 1,500, 2,000, 2,500, 5,000, 7,500, 10,000, 15,000, 20,000, 25,000, 30,000, 35,000, 40,000, 45,000, 50,000, 75,000, 100,000, 150,000, 200,000, 500,000, 750,000 or about 1,000,000 cm 2 or greater. The galvanic cell can have any suitable ratio of anode surface area to cathode surface area, such as a ratio of anode surface area exposed to water to cathode surface area exposed to water, such as about 0.1 to about 10, 0.5 to 2, or less than, equal to, or greater than about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.8, 3, 3.5, 4, 4.5, 5, 5.5, 6, 7, 8, 9, or about 10 or more. In some embodiments, the anode, cathode, or combination thereof includes a roughened or etched surface to increase the surface area. For the methods described herein, any suitable number of primary cells can be used, such as 1, 1 to 1,000,000, 1 to 1,000, 1 to 20, or less than, equal to, or greater than 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 60, 70, 80, 90, 100, 125, 150, 175, 200, 225, 250, 300, 400, 500, 750, 1,000, 1,250, 1,500, 1,750, 2,000, 2,500, 3,000, 4,000, 5,000, 10,000, 20,000, 50,000, 100,000, 250,000, 500,000 or about 1,000,000 or more. The cells can be used in a series or parallel electrical arrangement.

[0102] The galvanic cell may include a spacing between a surface of the anode and a surface of the cathode (e.g., between the cathode and at least about 50% to 100% of the surface area of ​​the anode, or about 80% to about 100%, or less than, equal to, or greater than about 50%, 55, 60, 65, 70, 75, 80, 85, 90, 95, 96, 97, 98, or about 99% or more of the surface area of ​​the anode) of about 1 mm to about 110 mm, or about 2 mm to about 30 mm, or less than, equal to, or greater than about 1 mm, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 32, 34, 36, 38, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, or 110 mm, or more.

[0103] The galvanic cell may be planar in form, having a thickness less than the height and width. The galvanic cell may include a planar frame of the galvanic cell and a cathode material contained within the periphery of the frame, wherein the cathode material is electrically connected to the frame (e.g., by direct contact therewith). The frame may be a structural component of the galvanic cell. The frame is structurally sufficient to maintain its shape without any or all anodes. Both the planar frame and the cathode material contained within the periphery of the frame may be cathodes.

[0104] The planar frame can be a non-porous solid material. The planar frame can be one or more cathode material strips assembled to form a frame. The planar frame can have a polygonal perimeter, such as a square or rectangle. The cathode material contained within the perimeter of the planar frame can include a porous cathode material, for example, including a wire, a mesh, a screen, a sheet including one or more through holes, or a combination thereof. The porous cathode material can include a wire mesh or a wire screen containing the porous cathode material. The porous cathode material contained within the perimeter of the planar frame can have an edge sandwiched between two planar frames, which are held together by compression, or by a conductive connector passing through one or more through holes of the porous cathode material, or by a combination thereof, with one or more of the conductive connectors fixing the porous cathode material therebetween.

[0105] The galvanic cell may include a plurality of pairs of planar frames (e.g., 2 to 20 pairs, or 2 to 10 pairs, or less than, equal to, or greater than 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 or more pairs), each pair of planar frames being held together to secure the porous cathode material therebetween using one or more of the conductive connectors, and each pair of planar frames being separated by one or more of the anodes spanning the porous cathode material contained within the perimeter of the planar frames. The one or more anodes separating each pair of planar frames from each other may directly contact a face of each pair of planar frames separated by them. The one or more anodes separating each pair of planar frames from each other may directly contact a face of one of each pair of planar frames separated by them, and may not directly contact a face of another of each pair of planar frames separated by them.

[0106] The anode may be a strip fastened to the planar frame at two edges of the planar frame, wherein the anode is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors so that the anode spans the cathode material contained within the perimeter of the planar frame, forming a gap between the cathode material contained within the perimeter of the planar frame and the anode strip. The anode and cathode may directly contact each other at each of the edges of the planar frame, wherein the anode is fastened to the planar frame by at least one conductive connector.

[0107] The galvanic cell may include a plurality of anodes, wherein each anode is a strip fastened to the planar frame at two edges of a planar frame on a face of the frame, wherein each of the anodes is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors so that each of the anodes spans the cathode material contained within the perimeter of the planar frame, forming a gap between the cathode material contained within the perimeter of the planar frame and the anode strips, wherein the plurality of anodes are spaced apart across the face so that they are not in physical contact with each other. Each of the anodes may span the cathode material contained within the perimeter of the planar frame substantially parallel to each other on the face; the anodes on the other face of the planar frame may be parallel or perpendicular to the anodes on the first face. The two edges of the planar frame to which each anode is fastened may be opposing edges of the planar frame. The galvanic cell may have all of its anodes on a single major face of the planar frame, or some anodes may be on one major face of the planar frame and others on another major face of the frame.

[0108] Figure 1AA galvanic cell 110 is shown from the main face according to various embodiments. The galvanic cell 110 includes a cathode, wherein the cathode includes a planar frame 120 of the galvanic cell having a polygonal perimeter and a porous material 130 contained within the perimeter of the frame, the porous material being a wire mesh or wire screen in direct contact with the frame. The galvanic cell 110 includes a plurality of anodes 140, wherein each anode is a strip fastened to the planar frame at two opposite edges of the planar frame on the face of the planar frame. Each of the anodes is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors 150, so that each of the anodes is approximately parallel to each other and spans the porous material contained within the perimeter of the planar frame, forming a gap (not shown) between the porous material contained within the perimeter of the planar frame and the anode strip. Each anode directly contacts the cathode frame at each of the edges of the planar frame, wherein the anode is fastened to the planar frame by at least one conductive connector. Conductive connectors (not shown) that only pass through the planar frame 120 can also be used to fix the porous material 130 therebetween. The plurality of anodes are spaced across the face such that they are not in physical contact with each other and wherein the gap (not shown) is from about 1 mm to about 110 mm.

[0109] Figure 1B Shown along Figure 1A The right side shows an enlarged cross-sectional view of a galvanic cell 110 viewed from a perspective view. The galvanic cell may include a plurality of pairs of planar frames 120, wherein each pair of planar frames is held together to secure a porous cathode material 130 therebetween using one or more of the conductive connectors (not shown). The anode 140 spans across the porous cathode material 130 contained within the perimeter of the planar frames 120. Each pair of planar frames 120 is supported by the anode 140 ( Figure 1B The one or more anodes 140 that separate each pair of planar frames from each other may directly contact the surface of each pair of planar frames 120 that are separated by them.

[0110] In various embodiments, the galvanic dephosphorization stage can also reduce the concentration of or remove other toxic or regulated materials, such as those formed in the electrolytic denitrification stage, such as oxidized materials (e.g., chlorates, chlorites, bromates, etc.). Such oxidized species can polarize the galvanic cell, which can be beneficial to the oxidation kinetics of the metallic aluminum.

[0111] In embodiments of the galvanic cell comprising aluminum in the anode, dissolution of the aluminum anode during operation of the galvanic cell produces a high local concentration of aluminum ions at or very near the surface of the electrode, which is favorable for supersaturation and thermodynamic conditions for precipitation of aluminum phosphate compounds. Such surface conditions produce a low molar ratio of metal to phosphorus even if the phosphorus level in the water is less than 0.1 ppm. The resulting equilibrium concentration of the remaining phosphate in the solution may be much lower than that obtained by simply adding aluminum salts to the water. When aluminum salts are added to water containing phosphate in order to obtain a phosphorus concentration of less than about 0.1 ppm, the molar ratio of metal to phosphorus must be close to 8. In contrast, in the galvanic method described herein, the molar ratio of metal to phosphorus can be less than 8, for example about 1.

[0112] Optional further nitrogen removal section.

[0113] The method for removing phosphorus and nitrogen optionally includes (e.g., includes or does not include) one or more additional stages for removing nitrogen from the water after the water has passed through the galvanic phosphorus removal stage. The one or more additional stages may include any suitable method for removing additional nitrogen from the water.

[0114] In some embodiments, the optional further nitrogen removal section includes removing nitrates. The optional further nitrogen removal may include exposing the water to denitrifying bacteria to convert the water-soluble nitrogen therein into nitrogen gas to be removed, as described in WO 2020 / 046679, which is incorporated herein by reference in its entirety. The method may include deoxygenating the water before further removing nitrogen therefrom. The method may include oxidizing or hydrolyzing at least some of the nitrogen in the water to form nitrates before further removing nitrogen therefrom. The method may include reoxygenating the water after further removing nitrogen therefrom.

[0115] In some embodiments, the optional further nitrogen removal stage includes optionally oxidizing or hydrolyzing at least some of the nitrogen in the water to form nitrates; optionally deoxygenating the water to an oxygen concentration of about 0 ppm to about 0.3 ppm; exposing the water to denitrifying bacteria immobilized on a porous substrate to convert nitrates in the water to nitrogen gas that is removed and form denitrified water; and optionally reoxygenating the denitrified water to an oxygen concentration of about 1 ppm to about 20 ppm.

[0116] The denitrified water may have a total nitrogen concentration of about 0.0 ppm to about 2 ppm total nitrogen.

[0117] Methods of removing nitrogen from water.

[0118] Various embodiments of the present invention provide a method for removing nitrogen from water. The method may include passing the water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas. The method may include any of the features described herein for the electrolytic nitrogen removal stage.

[0119] Prior to passing through the electrolytic cell, the water can have any suitable chloride concentration, e.g., 50 ppm to 40,000 ppm, 200 ppm to 10,000 ppm, or 50 ppm or more, or less than, equal to, or greater than 100 ppm, 200, 500, 1,000, 2,000, 4,000, 6,000, 8,000, 10,000, 15,000, 20,000, 30,000, or 40,000 ppm or less.

[0120] The water may be passed through a single electrolytic cell or multiple electrolytic cells. The water passing through the electrolytic cells is allowed to contact the anode and cathode and may flow between the anode and cathode. The water passing through the electrolytic cells may partially or completely submerge / immerse the electrolytic cells. Shear may be applied to the water as it passes through the electrolytic cells to increase exposure of the water to the cathode and anode surfaces.

[0121] The water in which the electrolytic cell is immersed can have any suitable pH, such as 6 to 12, 6 to 7, or 6 or more, or less than, equal to, or greater than 6.5, 7, 7.5, 8, 8.5, 9, 9.5, 10, 10.5, 11, 11.5, or 12 or less. The method may include adding one or more bases to the water to adjust or maintain the pH of the water, such as sodium hydroxide; in other embodiments, the method does not add an acid or base to the water to maintain or adjust its pH.

[0122] The electrolytic cell may be operated in any suitable manner to remove nitrogen from water in the form of nitrogen gas. The cell may be operated with direct current or alternating current. The electrolytic cell may be operated at any suitable current density, for example 0.001-0.1 A / cm 2 , 0.02-0.04A / cm 2 or 0.001A / cm 2 or more, or less than, equal to, or greater than 0.005, 0.01, 0.015, 0.02, 0.025, 0.03, 0.035, 0.04, 0.045, 0.05, 0.06, 0.07, 0.08, 0.09, or 0.1 A / cm 2 or smaller.

[0123] The electrolytic cell includes an anode. The anode may comprise titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti); or titanium oxide and ruthenium oxide supported on titanium (TiO2-RuO2 / Ti); or titanium and platinum (Ti-Pt); or a combination thereof. The anode and cathode materials may be selected so that the electrodes facilitate the formation of chlorine gas to form hypochlorite during operation of the electrolytic cell.

[0124] The electrolytic cell includes a cathode. The cathode may comprise titanium, stainless steel, or a combination thereof. The cathode may comprise stainless steel.

[0125] The electrolytic cell can include a spacing between the anode and cathode of, for example, 0.5-8 mm, 2-4 mm, or 0.5 mm or more, or less than, equal to, or greater than 1 mm, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 6, 7, or 8 mm or less.

[0126] The method is not limited to any particular mechanism for removing nitrogen from water in the form of ammonia using an electrolytic cell. Removing nitrogen in the form of nitrogen gas may include using an electrolytic cell to convert ammonia in the water into nitrogen gas. Passing the water through an electrolytic denitrification stage may produce hypochlorite in the water, which may react with ammonia in the water to form nitrogen gas, which may be released into the environment. The electrolytic cell can produce any suitable hypochlorite concentration in the water passing therethrough, such as 100-20,000 ppm hypochlorite, 2000-2500 ppm, or 100 ppm or greater, or less than, equal to, or greater than 200 ppm, 400, 600, 800, 1,000, 1,200, 1,400, 1,600, 1,800, 2,000, 2,100, 2,200, 2,300, 2,400, 2,500, 2,600, 2,800, 3,000, 4,000, 6,000, 8,000, 10,000, 15,000, or 20,000 ppm or less.

[0127] The method can remove any suitable amount of nitrogen from the water. For example, passing the water through an electrolytic denitrification stage can remove 80% to 100%, 99-100%, or 80% or more, or less than, equal to, or greater than 81%, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, 99.99, or 99.999% or less of ammonia from the water.

[0128] In various embodiments, the method of removing nitrogen from water in the form of nitrogen gas may also include removing phosphorus from the water, such as any suitable amount of phosphorus. For example, passing the water through an electrolytic denitrification stage may remove 0.1% to 90% of the active phosphorus from the water, or 1-30%, or 0.1% or more, or less than, equal to, or greater than 2%, 4, 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26, 28, 30, 40, 50, 60, 70, 80, or 90% or less.

[0129] Systems for removing nitrogen and phosphorus from water.

[0130] Various embodiments of the present invention provide a system for removing nitrogen and phosphorus from water. The system can be any suitable system that can perform the method for removing nitrogen and phosphorus from water described herein. The system can include a phosphorus removal section for increasing pH, which is configured to increase the pH of the starting raw water to greater than or equal to 7.5 to precipitate phosphorus salts from the water and is configured to remove the precipitated phosphorus salts from the water. The system can include an electrolytic denitrification section, which includes an electrolytic cell configured to remove nitrogen from water in the form of nitrogen gas. The system can include a galvanic dephosphorization section, which includes a galvanic dephosphorization section, which includes a galvanic cell, which includes an anode, which includes Mg, Al, Fe, Zn or a combination thereof; and a cathode having a different composition from the anode, which includes Cu, Ni, Fe or a combination thereof. The galvanic cell can be configured to form treated water, which includes salts containing phosphorus from water. The galvanic dephosphorization section can be configured to separate phosphorus-containing salts from the treated water.

[0131] The water produced by this system has a lower phosphorus concentration and a lower nitrogen concentration than the starting feed water.

[0132] Equipment for removing nitrogen from water.

[0133] Various embodiments of the present invention provide an apparatus for removing nitrogen from water. The apparatus can be any suitable apparatus that can perform the method for removing nitrogen from water described herein. The apparatus can include an electrolytic cell through which water is configured to flow to remove nitrogen from water in the form of nitrogen gas. The electrolytic cell includes a cathode that can include stainless steel and / or titanium. The electrolytic cell includes an anode that can include titanium oxide, ruthenium oxide, and iridium oxide (TiO2-RuO2-IrO2 / Ti) supported on titanium, or titanium oxide and ruthenium oxide (TiO2-RuO2 / Ti) supported on titanium, or titanium and platinum (Ti-Pt), or a combination thereof. The anode and cathode materials can be selected so that the electrodes are conducive to the formation of chlorine gas to form hypochlorite during operation of the electrolytic cell. Using the apparatus to remove nitrogen in the form of nitrogen gas can remove 80-100% of ammonia from water.

[0134] Example

[0135] Various embodiments of the present invention may be better understood by reference to the following examples which are provided by way of illustration.The present invention is not limited to the examples given herein.

[0136] Various sizes of galvanic cells were used to evaluate various aspects of the methods outlined in the examples. The galvanic cells are referred to as "small", "medium" and "large" as defined below. The magnesium anode is AZ91 with 90 wt% Mg, 9 wt% Al and 1 wt% Zn and is 99.9% pure. The aluminum anode is 99.9 wt% pure aluminum. The copper used in the copper frame and copper mesh is 99.9 wt% pure copper.

[0137] For small cells with copper cathodes and aluminum or magnesium anodes, the final size is 5cm x 20cm, the thickness is about 4mm, and copper mesh and anode each having a thickness of about 1mm are used. The small size battery includes a single pair of copper meshes with an anode sandwiched between them, and the copper mesh and anode are separated from the copper mesh by 0.5cm using electrically insulating plastic screws. The copper meshes are electrically connected to each other by copper wires. The anode and cathode are not electrically connected to each other (except through a multimeter and surrounding water). The resulting surface area of ​​the sacrificial anode exposed to water is about 400mm per battery. 2 . Figure 2A A photograph along the edge of an Al-Cu electrochemical cell is shown.

[0138] For a medium-sized cell with a copper cathode and an aluminum or magnesium anode, the final dimensions were 300 cm x 45 cm, about 10 mm thick, and a single pair of copper mesh with the anode sandwiched between them was used. The copper mesh was in direct contact with the anode and was connected to the anode by a brass bolt (plain brass, 67 wt% copper and 33 wt% Zn). The resulting surface area of ​​the sacrificial anode exposed to water was about 31,400 mm per cell. 2 . Figure 2B Shown are photographs along the edges of several mesoscale Al-Cu electrochemical cells.

[0139] The large-size electrochemical cell used in the embodiment includes a cathode, which is a pair of planar solid copper frames sandwiching a copper mesh, wherein a brass connector fixes the copper frames together to fix the copper mesh between the frames. The solid copper frame forms the rigid structural periphery of the battery, wherein the copper mesh fills the entire area within the periphery of each pair of copper frames. A plurality of anode strips (which are magnesium alloys or aluminum) are fixed to the periphery of the frame with brass fasteners so that they span from one edge of the frame to another frame, directly contact the frame and form a gap between the anode and the copper mesh. Each electrochemical cell includes two pairs of copper frames (i.e., a total of four copper frames, with two copper meshes) with a copper mesh therebetween. The first pair of copper frames has an anode fixed to its single main face, and the second pair of copper frames has an anode fixed to its two main faces, wherein the two pairs of copper frames are fixed to each other with brass fasteners so that they will not directly contact each other, and so that they clamp the anode fixed to one main face of the second pair of copper frames. The brass fasteners are ordinary brass, and are 67% by weight copper and 33% by weight Zn. The anodes are horizontally across each major face of the copper frame and parallel to each other, with 6 anodes fixed on each face. From one major face of the electrochemical cell to another, the order of the components is 1) anodes fixed to one major face of the first pair of copper frames, 2) the first pair of copper frames with copper mesh between them, 3) anodes fixed to one major face of the second pair of copper frames, 4) the second pair of copper frames with copper mesh between them, and 5) anodes fixed to the other major face of the second pair of copper frames. The ratio of the anode surface area to the cathode surface area of ​​the electrochemical cell is about 1:1.

[0140] For large-size batteries, each copper frame has a thickness of 3.175 mm (1 / 8 inch). The height of the copper frame is 400 mm and the length of the copper frame is 400 mm. The copper mesh has a thickness of 1.5875 mm, so that each pair of copper frames sandwiching the copper mesh has a thickness of about 8 mm. The anode strip has a length of 400 mm, a width of 45 mm and a thickness of 6 mm. The thickness of the entire electrochemical cell is about 30 mm. The gap between the anodes on each face of the copper frame is 12-18 mm. The gap between the anode fixed to each pair of copper frames and the copper mesh sandwiched therebetween is 12-18 mm. Large-size batteries using aluminum anodes include about 290,000 mm 2 The anode surface area exposed to water for large-scale batteries using magnesium includes approximately 868,000 mm 2 of the anode surface area exposed to water.

[0141] Figure 2C A photograph showing the main surface of a large-scale Mg-Cu electrochemical cell used in Examples. Figure 2D and 2E Shown is a close-up photograph of the edge of a large-scale Mg-Cu electrochemical cell used in the Examples.

[0142] In the embodiments herein, the Al-Cu or Mg-Cu electrochemical cell is completely immersed in the water in the container so that the electrochemical cell is oriented vertically and the anode extends vertically. When multiple electrochemical cells are used, they are separated by about 25 mm using a wooden frame. In the middle of the container, the water therein is stirred using a mechanical stirrer. The water is filtered and pumped into the container using a pump. Another pump is used to circulate water and filter water (e.g., to remove sediment therefrom) in the container, and the water is pumped from one side of the container and recirculated to the other side. HCl is added to the container using a pump connected to a reservoir of 10% HCl to adjust the pH of the water therein. The water in the container is measured to determine its pH, which is used to determine the amount of acid that needs to be added from the reservoir to maintain a specific pH. The water fed into the container is analyzed to determine the initial pH, initial conductivity, and initial active phosphorus content. For the Mg-Cu battery, the water fed into the container is also analyzed to determine the initial dissolved magnesium content. The pH and conductivity of the water in the container are measured. The container includes a drain at the water level of the container to allow water to leave the system. The water leaving the system is analyzed to determine the final pH, final conductivity, and final active phosphorus content. For Al-Cu cells, the water leaving the container is analyzed to determine total Al and dissolved Al. For Mg-Cu cells, the water leaving the container is analyzed to determine dissolved magnesium content. Figure 2F A photograph showing a top view of the system used in the Examples is shown, wherein the specific embodiment shown in the photograph has 12 electrochemical cells (6 in the front and 6 in the back arranged side by side with the 6 in the front). Figure 2G A photograph showing a side view of the system used in the Examples is shown, with a specific embodiment having 12 electrochemical cells therein.

[0143] "Active phosphorus concentration" refers to the soluble active phosphorus (e.g., orthophosphate) in solution and is measured by US-EPA 365.1: Semi-automated colorimetric determination of phosphorus. The pH 700 meter measures pH. Thermo Scientific CON 150 meters measure conductivity. TM Dionex TM Aquion TM Ion chromatography system to measure dissolved magnesium content. Using Hach Aluminum TNT plus TM The vial test measures total and dissolved aluminum content. Dissolved Al is determined at the pH of the water leaving the container. Total Al content is determined by adjusting the pH to 2.

[0144] Part I. Primary Batteries.

[0145] Example 1. Removal of phosphorus using Al-Cu battery, initial P concentration is 0.033 ppm

[0146] The residence time in the galvanic method was modified by taking water from one of the channels of a local lake and adjusting the water flow to provide a specific residence time while keeping the other variables of the system (pH, conductivity and phosphorus concentration) constant. The residence time (i.e., the volume of the container divided by the flow rate) was gradually reduced until the removal performance decreased and then remained constant in this example. For low initial phosphorus concentrations (0.033 ppm), the residence time was reduced to about 15 minutes while maintaining an average phosphorus removal of about 90%. The Al-Cu cell was of medium size. The results are shown in Table 1.

[0147] Table 1. Phosphorus removal using Al-Cu cells, initial P concentration 0.033 ppm.

[0148]

[0149] Example 2. Removal of phosphorus using Al-Cu battery, initial P concentration is 0.451 ppm

[0150] Water from a local inland wastewater treatment facility was treated to evaluate the effect of increasing solution conductivity. During this example, the residence time was kept constant at 21 minutes. The conductivity was varied by adding NaCl. This example demonstrates the beneficial effect of increased conductivity on phosphorus removal efficiency. The Al-Cu cell is of medium size. The results are shown in Table 2.

[0151] Table 2. Phosphorus removal using Al-Cu cells, initial P concentration 0.451 ppm, cell size = medium

[0152]

[0153] Example 3. Phosphorus removal using Al-Cu battery, initial P concentration is 0.392ppm.

[0154] A coastal wastewater treatment plant effluent with high conductivity was treated using a moderate Al-Cu cell. As noted in Example 2 above, increased conductivity is beneficial. The water treated in this example came from a coastal area where salt (NaCl) concentrations resulted in increased conductivity. The purpose of this example was to evaluate the loss of sacrificial electrode material in the treated aqueous solution and to evaluate this relationship as a function of pH. The final phosphorus removal efficiency remained unchanged; however, the concentration of total aluminum (dissolved and solid) decreased when the pH was changed from pH 7 to pH 6.5. This example demonstrates the ability to control the loss of material from the sacrificial electrode by adjusting the pH. The results are shown in Table 3.

[0155] Table 3. Phosphorus removal using Al-Cu cells, initial P concentration 0.392 ppm, cell size = medium

[0156]

[0157] Example 4. Removal of phosphorus using Al-Cu battery, initial P concentration is 0.648-0.762 ppm

[0158] Water from a local freshwater reservoir was spiked with phosphoric acid to obtain a phosphorus concentration of 0.75 ppm and treated using multiple galvanic cells in a continuous flow unit with a flow rate of about 2 gallons per minute (GPM) (large cells). The pH of the water was gradually adjusted down to values ​​between 7 and 6. An increase in the percent removal from 82% at pH = 7 to 97% at pH = 6 was observed, with a concomitant reduction in the soluble aluminum remaining in the treated water. The results are shown in Table 4.

[0159] Table 4. Phosphorus removal using Al-Cu cells, initial P concentration 0.648-0.762 ppm, cell size = large

[0160]

[0161] Example 5. Effect of conductivity on the current generated by Al-Cu battery and its relationship with time

[0162] Using a small cell, aluminum foil and copper screen measuring 5cm x 2cm were separated by 0.5cm using plastic screws. The aluminum foil / copper was placed in a simple compartment with magnetic stirring, which was filled with 30mL of water from a local freshwater reservoir. The current was measured using a Keithley 175 multimeter in series. The initial conductivity was adjusted with NaCl. The current generated by the Al-Cu galvanic couple in the Al-Cu cell was measured. This current is a measure of the amount of anode material converted in the electrode over time, such as aluminum oxidation reaction to produce aluminum ions and water decomposition on the copper electrode to produce hydrogen and hydroxide ions.

[0163] Figure 3 The current generated by the Al-Cu galvanic couple is shown as a function of the conductivity of the solution. The initial pH of the water did not change and was about 7. Increasing the initial conductivity of the solution to a value of 1000 μS increases the current due to the reduced resistance between the electrodes, thereby increasing the rate of the chemical reaction at the electrode surface. Similar results were obtained in Example 2. Increasing the conductivity to values ​​above 1000 μS resulted in almost no change in the current, because at higher conductivity values ​​the rate-limiting step of the reaction is the kinetics of the chemical process at the surface of the electrode.

[0164] Example 6. Effect of pH on the Current Generated by Al-Cu Battery and Time

[0165] The same experimental conditions as in Example 5 were used, but the initial pH was adjusted with NaOH, where the initial conductivity of the water was adjusted to about 1000 μS with NaCl. Figure 4 The current generated by the Al-Cu galvanic couple varies with the pH of the solution. Lowering the pH of the solution favors the decomposition kinetics of water on the copper electrode, which is converted into an increase in the current through the Al-Cu galvanic couple.

[0166] Example 7. Effect of conductivity on the current generated by Mg-Cu battery as a function of time

[0167] The same experimental conditions as in Example 5 were used, the pH was not changed, and the conductivity was changed using NaCl. Figure 5A The current circulating in the Mg-Cu galvanic couple is shown as a function of the water conductivity of a local freshwater reservoir. An increase in the water conductivity results in a significant increase in the current flowing through the electrochemical cell. Figure 5B The effect of this conductivity increase on the kinetics of chemical reactions is shown in , where it improves the kinetics of the pH increase.

[0168] Example 8. Mg-Cu battery, initial P concentration is 0.392-0.451

[0169] Two water bodies from treatment plants were compared; the conductivity of water collected from a coastal wastewater treatment plant (WWTP) was three times that of water from an inland WWTP due to the presence of salt water in the treatment system. Higher conductivity favors reaction kinetics, and therefore for the same residence time, more phosphorus removal occurs in the higher conductivity water while consuming the same amount of sacrificial anodes as the lower conductivity (resulting in the same amount of magnesium ions in solution). The Mg-Cu cell is of medium size. The results are shown in Table 5.

[0170] Table 5. Mg-Cu cells, initial P concentration 0.392-0.451, cell size = medium.

[0171]

[0172]

[0173] Part II. Galvanic cells for the dephosphorization section and the electrolytic denitrification section.

[0174] Example 9

[0175] The water obtained is residual process water from a phosphate rock reservoir at about pH 4.3 and containing about 260 ppm NH3, 120 ppm active phosphorus, 3600 ppm Na, 500 ppm Mg, 280 ppm Ca, and 5800 ppm chloride. The water is stored in 250 gallon shipping tanks for use as influent water.

[0176] The influent water is continuously pumped from the shipping box to a 3-gallon tank called a mixing tank via a Cole Parmer peristaltic pump and tubing at a rate of 100 mL / min. A mixer is installed in the mixing tank to ensure good mixing. About 5% sodium hydroxide is continuously added at a rate of about 0.5 mL / min via a Cole Parmer pump and tubing to maintain the pH of the mixing tank at 8.5. An anionic polymer flocculant (0.01%) dissolved in water is added in a similar manner to bring the mixing tank flocculant concentration to about 5 ppm. When the water enters the mixing tank, its pH will increase from 4.3 to 8.5, and calcium phosphate, magnesium ammonium phosphate and other unknown precipitates will be formed. The total solid content is about 500 ppm. The solid concentration is determined by weighing a 5-micron filter bag after a set period of time and dividing it by the total flow during this period. The solids are then contacted with the flocculant, increasing the particle size, and overflowing from the mixing tank into a 5-micron bag filter. The solids are removed from the water, leaving 4 to 8 ppm of active phosphorus and 180-200 ppm of NH3-N in the water. Reactive phosphorus, ammonia, and free and total chlorine are determined by the HACH test kit and appropriate colorimetric methods on a spectrophotometer.

[0177] After passing through a 5 micron bag filter, it flows by gravity into a 3 gallon settling tank to allow any remaining sediment to settle to the bottom of the tank. These solids are cleaned out periodically by passing the entire settling tank through a 5 micron filter again as needed.

[0178] Water was then pumped from the top of the settling tank to the electrolyzer via a Cole Parmer peristaltic pump and tubing at 100 mL / min. This water is called post-settling tank water.

[0179] The electrolytic cell was a 1.5L plastic container. Inside the electrolytic cell there was a mixer and electrodes to ensure good mixing. The electrodes were prepared using a 9"x2" screen of titanium oxide, ruthenium and iridium oxide (TiO2-RuO2-IrO2 / Ti) supported on titanium as the anode and a 9"x2" 304 stainless steel screen as the cathode. The anode and cathode were secured together about 2-4mm from each other using several plastic nuts and bolts. A set of brass nuts and bolts were secured through each anode and cathode screen respectively to provide contact points for the DC generator. The anode and cathode were connected to the DC generator via alligator clips provided with the DC generator. The DC generator was set to provide 6.5 amps and about 4.2 volts of power. The electrode produced 2000 to 2500 ppm of bleach by oxidation of chloride in the solution. Side reactions at the cathode also resulted in the precipitation of residual calcium and phosphorus on the surface of the electrode, and a drop in pH. To maintain an appropriate pH of about 7, 2.5% sodium hydroxide was added to the mixing tank in a similar manner. The bleach produced reacts with ammonia to produce nitrogen which is released into the atmosphere. Side reaction precipitates are manually cleaned from the cathode as needed to remove them from the surface of the electrode. The entire electrolytic cell is poured into a 5 micron filter after the mixing tank to remove solids from the water. The water then overflows the electrolytic cell containing 0.1 to 2 ppm active phosphorus, 0 to 1 ppm NH3, and 0 to 300 ppm residual free chlorine and total chlorine.

[0180] The water overflowed into a 1 L chlorine contact tank to allow the residual chlorine to continue to react with any residual ammonia. Finally, the water overflowed the chlorine contact tank containing 0 to 300 ppm residual free and total chlorine, 0 to 0.3 ppm NH3-N, and 0 to 2 ppm active phosphorus. The water from this point was recorded as the effluent water. A summary of the data is shown in Table 6. The water then flows into a galvanic system to remove any residual phosphorus, bleaching agents, and unwanted oxidation byproducts.

[0181] Table 6. Data for Example 9. Mixing tank pH = 8.5. All samples were averaged and given in ppm

[0182]

[0183] Example 10. Evaluation of increased pH and resulting phosphorus and ammonia removal

[0184] Example 10 was conducted in a similar manner to Example 9, with the primary difference being that the mixing tank pH was adjusted to 9.3 instead of 8.5. This change in pH caused about 4200 ppm of solids to precipitate in the mixing tank and combine with the flocculant to be filtered out. The water leaving the mixing tank had 0 to 2 ppm active phosphorus and 150 to 200 ppm NH3-N after filtering through a 5 micron bag filter.

[0185] The water enters the electrolytic cell in a similar manner as in Example 9. Once in the electrolytic cell, electrolysis is conducted in a similar manner, the main differences being that less solids are precipitated on the stainless steel cathode, less frequent cathode cleaning is required, and less sodium hydroxide is required to maintain the proper pH of 7. The water then overflows the electrolytic cell containing 0 to 0.5 ppm active phosphorus, 0 to 1 ppm NH3-N, and 0 to 300 ppm residual free chlorine and total chlorine.

[0186] The water overflowed into a 1 L chlorine contact tank to allow the residual chlorine to continue to react with any residual ammonia. Finally, the water overflowed the chlorine contact tank containing 0 to 300 ppm residual free chlorine and total chlorine, 0 to 0.3 ppm NH3-N, and 0 to 0.5 ppm active phosphorus. A summary of the data is shown in Table 7.

[0187] Table 7. Data for Example 10, mixing tank pH = 9.3, average values ​​for all samples and given in ppm

[0188]

[0189] Example 11. Current density, resulting hypochlorite production and corresponding ammonia reduction

[0190] Example 11 was conducted in a similar manner to Example 10. In Example 11, the effect of varying the current density on the generation of bleach and the removal of ammonia was examined.

[0191] The water was passed through the mixing tank, settling tank, electrolysis tank and contact tank in a similar manner to Example 10.

[0192] The current through the electrode was tested at 8 amps, 7.5 amps, 7 amps, and 6.5 amps, with other characteristics held constant. As shown in Table 8, higher currents produced more bleach than lower currents, but all densities produced enough bleach to completely remove all ammonia. 6.5 amps was found to be approximately optimal for the ammonia concentrations in this example.

[0193] Table 8. Example 11 data. Effect of current density on bleach generation. All samples are averaged and given in ppm unless otherwise stated.

[0194]

[0195] The terms and expressions used are used as terms of description rather than limitation, and the use of these terms and expressions is not intended to exclude any equivalents of the features shown and described or parts thereof, but it should be recognized that various modifications can be made without departing from the scope of the embodiments of the present invention. Therefore, it should be understood that although the present invention has been specifically disclosed through specific embodiments and optional features, those of ordinary skill in the art may make modifications and changes to the concepts disclosed herein, and such modifications and changes are considered to be within the scope of the embodiments of the present invention.

[0196] Exemplary embodiments

[0197] The following exemplary embodiments are provided, the numbering of which should not be construed as designating a level of importance:

[0198] Embodiment 1 provides a method for removing phosphorus and nitrogen from water, the method comprising:

[0199] The starting feed water containing nitrogen and phosphorus is passed through a phosphorus removal section with an elevated pH, comprising

[0200] Raising the pH of the water to greater than or equal to 7.5 to precipitate phosphate salts from the water; and

[0201] Removal of precipitated phosphate salts from water;

[0202] The water is passed through an electrolytic denitrification process, including

[0203] passing the water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas; and

[0204] Pass the water through the galvanic dephosphorization section, including

[0205] immersing the galvanic cell in water to form treated water containing a salt containing phosphorus from the water, the galvanic cell comprising

[0206] an anode comprising Mg, Al, Fe, Zn or a combination thereof,

[0207] a cathode having a different composition than the anode, the cathode comprising Cu, Ni, Fe, or a combination thereof; and

[0208] separation of phosphorus-containing salts from treated water;

[0209] The water produced by the process has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw water.

[0210] Embodiment 2 provides the method of embodiment 1, wherein the starting raw material water is water from a phosphate rock reservoir.

[0211] Embodiment 3 provides the method of any one of embodiments 1-2, wherein the starting raw water is water derived from a process of dissolving phosphate-containing rocks to produce phosphoric acid.

[0212] Embodiment 4 provides the method of any one of embodiments 1-3, wherein the starting raw material water has a pH of less than 7.5.

[0213] Embodiment 5 provides the method of any one of embodiments 1-4, wherein the starting raw material water has a pH of 4-5.

[0214] Embodiment 6 provides the method of any one of embodiments 1-5, wherein the phosphorus in the starting raw water is in the form of elemental phosphorus, inorganic phosphorus, organic phosphorus, dissolved phosphorus, solid phosphorus, oxidized phosphorus, or a combination thereof.

[0215] Embodiment 7 provides the method of any one of embodiments 1-6, wherein the starting raw material water has an ammonia concentration of 50 ppm to 5,000 ppm.

[0216] Embodiment 8 provides the method of any one of embodiments 1-7, wherein the starting raw material water has an ammonia concentration of 150 ppm to 400 ppm.

[0217] Embodiment 9 provides the method of any one of embodiments 1-8, wherein the starting raw material water has an active phosphorus concentration of 10 ppm to 10,000 ppm.

[0218] Embodiment 10 provides the method of any one of embodiments 1-9, wherein the starting raw material water has an active phosphorus concentration of 50 ppm to 400 ppm.

[0219] Embodiment 11 provides the method of any one of embodiments 1-10, wherein the starting raw material water has a sodium concentration of 50 ppm to 20,000 ppm.

[0220] Embodiment 12 provides the method of any one of embodiments 1-11, wherein the starting raw material water has a sodium concentration of 400 ppm to 5,000 ppm.

[0221] Embodiment 13 provides the method of any one of embodiments 1-12, wherein the starting raw material water has a magnesium concentration of 10 ppm to 10,000 ppm.

[0222] Embodiment 14 provides the method of any one of embodiments 1-13, wherein the starting raw material water has a magnesium concentration of 50 ppm to 600 ppm.

[0223] Embodiment 15 provides the method of any one of embodiments 1-14, wherein the starting raw water has a chloride concentration of 50 ppm to 40,000 ppm.

[0224] Embodiment 16 provides the method of any one of embodiments 1-15, wherein the starting raw water has a chloride concentration of 200 ppm to 10,000 ppm.

[0225] Embodiment 17 provides the method of any one of embodiments 1-16, wherein the water produced by the method has a total phosphorus concentration of about 0 ppm to about 1 ppm.

[0226] Embodiment 18 provides the method of any one of embodiments 1-17, wherein the water produced by the method has a total phosphorus concentration of about 0.0001 ppm to 0.1 ppm.

[0227] Embodiment 19 provides the method of any one of embodiments 1-18, wherein the water produced by the method has a total phosphorus concentration of about 0.0001 ppm to 0.05 ppm.

[0228] Embodiment 20 provides the method of any one of embodiments 1-19, wherein the water produced by the method has a dissolved phosphorus concentration of about 0 ppm to about 1 ppm.

[0229] Embodiment 21 provides the method of any one of embodiments 1-20, wherein the water produced by the method has a dissolved phosphorus concentration of about 0.0001 ppm to 0.1 ppm.

[0230] Embodiment 22 provides the method of any one of embodiments 1-21, wherein the water produced by the method has a dissolved phosphorus concentration of about 0.0001 ppm to 0.05 ppm.

[0231] Embodiment 23 provides the method of any one of embodiments 1-22, wherein the water produced by the method has an active phosphorus concentration of about 0 ppm to about 1 ppm.

[0232] Embodiment 24 provides the method of any one of embodiments 1-23, wherein the water produced by the method has an active phosphorus concentration of about 0.0001 ppm to 0.1 ppm.

[0233] Embodiment 25 provides the method of any one of embodiments 1-24, wherein the water produced by the method has an active phosphorus concentration of about 0.0001 ppm to 0.05 ppm.

[0234] Embodiment 26 provides the method of any one of embodiments 1-25, wherein the water produced by the method has a total nitrogen concentration of about 0 ppm to about 2 ppm.

[0235] Embodiment 27 provides the method of any one of embodiments 1-26, wherein the water produced by the method has a total nitrogen concentration of about 0 ppm to about 1 ppm.

[0236] Embodiment 28 provides the method of any one of embodiments 1-27, wherein the water produced by the method has a dissolved nitrogen concentration of about 0 ppm to about 2 ppm.

[0237] Embodiment 29 provides the method of any one of embodiments 1-28, wherein the water produced by the method has a dissolved nitrogen concentration of about 0 ppm to about 1 ppm.

[0238] Embodiment 30 provides the method of any one of embodiments 1-29, wherein raising the pH of the water to precipitate phosphate salts from the water comprises raising the pH of the water to a range of 7.5 to 12.

[0239] Embodiment 31 provides the method of any one of embodiments 1-30, wherein raising the pH of the water to precipitate phosphate salts from the water comprises raising the pH of the water to 8.5 to 9.5.

[0240] Embodiment 32 provides the method of any one of embodiments 1-31, wherein raising the pH of the water to precipitate phosphate salts from the water comprises adding one or more bases to the water.

[0241] Embodiment 33 provides the method of any one of embodiments 1-32, wherein raising the pH of the water to precipitate phosphate salts from the water comprises adding one or more flocculants to the water.

[0242] Embodiment 34 provides the method of any one of embodiments 1-33, wherein removing the precipitated phosphate salt from the water comprises decantation, sedimentation, filtration, or a combination thereof.

[0243] Embodiment 35 provides the method of any one of embodiments 1-34, wherein the precipitated phosphate salt comprises magnesium ammonium phosphate, calcium phosphate, or a combination thereof.

[0244] Embodiment 36 provides the method of any one of embodiments 1-35, wherein the elevated pH phosphorus removal stage removes 70-100% of the active phosphorus in the water.

[0245] Embodiment 37 provides the method of any one of embodiments 1-36, wherein the elevated pH phosphorus removal stage removes 90-98% of the active phosphorus in the water.

[0246] Embodiment 38 provides the method of any one of embodiments 1-37, wherein the elevated pH phosphorus removal section removes 0-60% of the ammonia in the water.

[0247] Embodiment 39 provides the method of any one of embodiments 1-38, wherein the elevated pH phosphorus removal section removes 20-30% of the ammonia in the water.

[0248] Embodiment 40 provides the method of any one of embodiments 1-39, wherein the elevated pH phosphorus removal section comprises raising the pH of the water to 8.5 to 9.5 using one or more bases and removing precipitated phosphate salts comprising magnesium ammonium phosphate, calcium phosphate, or a combination thereof using decantation, sedimentation, filtration, or a combination thereof, wherein the elevated pH phosphorus removal section removes 90-98% of the active phosphorus in the water.

[0249] Embodiment 41 provides the method of any one of embodiments 1-40, wherein the water is passed through a plurality of said electrolytic cells.

[0250] Embodiment 42 provides the method of any one of Embodiments 1-41, wherein passing water through the electrolytic cell comprises partially submerging the electrolytic cell in water.

[0251] Embodiment 43 provides the method of any one of Embodiments 1-42, wherein passing water through the electrolytic cell comprises completely immersing the electrolytic cell in water.

[0252] Embodiment 44 provides the method of any of Embodiments 1-43, further comprising applying shear to the water as it passes through the electrolytic cell.

[0253] Embodiment 45 provides the method of any of Embodiments 1-44, wherein water is passed around and between the anode and cathode of the electrolytic cell.

[0254] Embodiment 46 provides the method of any one of embodiments 1-45, wherein the water passed through the electrolytic cell has a pH of 6 to 12.

[0255] Embodiment 47 provides the method of any one of embodiments 1-46, wherein the water passed through the electrolytic cell has a pH of 6 to 7.

[0256] Embodiment 48 provides the method of any of Embodiments 1-47, further comprising adding one or more bases to the water to adjust the pH of the water contacting the electrolytic cell.

[0257] Embodiment 49 provides the method of any one of embodiments 1-48, comprising operating the electrolytic cell with a direct current.

[0258] Embodiment 50 provides the method of any one of embodiments 1-49, comprising operating the electrolytic cell with an alternating current.

[0259] Embodiment 51 provides the method of any one of embodiments 1-50, comprising: 2The electrolytic cell was operated at a current density of 10 Å.

[0260] Embodiment 52 provides the method of any one of embodiments 1-51, comprising: 2 The electrolytic cell was operated at a current density of 10 Å.

[0261] Embodiment 53 provides the method of any one of embodiments 1-52, wherein the electrolytic cell comprises an anode and a cathode with a spacing therebetween of 0.5-8 mm.

[0262] Embodiment 54 provides the method of any one of embodiments 1-53, wherein the electrolytic cell comprises an anode and a cathode with a spacing of 2-4 mm therebetween.

[0263] Embodiment 55 provides the method of any of Embodiments 1-54, wherein the electrolytic cell comprises a cathode comprising titanium, stainless steel, or a combination thereof.

[0264] Embodiment 56 provides the method of any of Embodiments 1-55, wherein the electrolytic cell comprises a cathode comprising stainless steel.

[0265] Embodiment 57 provides the method of any one of Embodiments 1-56, wherein the electrolytic cell includes an anode comprising

[0266] Titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti), or

[0267] Titanium oxide and ruthenium oxide supported on titanium (TiO2-RuO2 / Ti), or

[0268] Titanium and platinum (Ti-Pt), or

[0269] A combination of them.

[0270] Embodiment 58 provides the method of any one of embodiments 1-57, wherein removing the nitrogen in the form of nitrogen gas comprises converting ammonia in the water into nitrogen gas using an electrolytic cell.

[0271] Embodiment 59 provides the method of any one of embodiments 1-58, wherein the water is passed through an electrolytic denitrification stage to produce hypochlorite, which reacts with ammonia in the water to form nitrogen gas.

[0272] Embodiment 60 provides the method of any one of embodiments 1-59, further comprising releasing the nitrogen to the atmosphere.

[0273] Embodiment 61 provides the method of any one of embodiments 1-60, wherein the water is passed through an electrolytic denitrification stage to remove 80-100% of the ammonia from the water.

[0274] Embodiment 62 provides the method of any one of Embodiments 1-61, wherein the water is passed through an electrolytic denitrification stage to remove 99-100% of the ammonia from the water.

[0275] Embodiment 63 provides the method of any one of embodiments 1-62, wherein the water is passed through an electrolytic denitrification stage to remove 0.1-90% of the active phosphorus from the water.

[0276] Embodiment 64 provides the method of any one of embodiments 1-63, wherein the water is passed through an electrolytic denitrification stage to remove 1-30% of the active phosphorus from the water.

[0277] Embodiment 65 provides the method of any one of Embodiments 1-64, wherein the electrolytic cell produces 100-20,000 ppm hypochlorite from chloride in water.

[0278] Embodiment 66 provides the method of any one of Embodiments 1-65, wherein the electrolytic cell produces 2000-2500 ppm hypochlorite from chloride in water.

[0279] Embodiment 67 provides the method of any one of embodiments 1-66, wherein:

[0280] wherein water is passed through an electrolytic denitrification section to produce hypochlorite, which reacts with ammonia in the water to form nitrogen; the cathode comprises stainless steel;

[0281] The anode comprises titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti); and

[0282] Passing the water through an electrolytic denitrification stage removes 80-100% of the ammonia from the water.

[0283] Embodiment 68 provides the method of any one of Embodiments 1-67, wherein the anode and cathode of the galvanic cell are in direct contact with each other.

[0284] Embodiment 69 provides a method as described in any one of embodiments 1-68, wherein the primary cell further comprises a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb or a combination thereof.

[0285] Embodiment 70 provides the method of embodiment 69, wherein the conductive connector comprises brass.

[0286] Embodiment 71 provides the method of any one of embodiments 1-70, wherein the galvanic dephosphorization section:

[0287] Reduce the total phosphorus concentration of the water by about 80% to about 100%, or

[0288] Reduce the dissolved phosphorus concentration of water by about 80% to about 100%, or

[0289] Reducing the active phosphorus concentration of water by about 80% to about 100%, or

[0290] Reduce the total nitrogen concentration of the water by about 70% to about 100%, or

[0291] Reduce the dissolved nitrogen concentration of water by about 70% to about 100%, or

[0292] A combination of them.

[0293] Embodiment 72 provides the method of any of Embodiments 1-71, wherein the phosphorus-containing salt comprises material from an anode of a galvanic cell.

[0294] Embodiment 73 provides the method of any one of embodiments 1-72, further comprising applying a mechanical force to the galvanic cell during immersion in water, or applying shear to the water during immersion in water, or a combination thereof, wherein the mechanical force and / or shear is sufficient to

[0295] expelling at least some of the bubbles comprising H from the surface of the anode, cathode, or a combination thereof, or

[0296] at least partially preventing oxide formation at the surface of the anode, or

[0297] at least partially preventing agglomeration of the phosphorus-containing salt on the surface of the anode, or

[0298] A combination of them.

[0299] Embodiment 74 provides the method of any one of embodiments 1-73, further comprising forming a salt comprising nitrogen from water during immersion of the galvanic cell in water, wherein separating the phosphorus-containing salt from the treated water further comprises separating the nitrogen-containing salt from the treated water.

[0300] Embodiment 75 provides the method of any one of Embodiments 1-74, wherein the cathode comprises Cu and the anode comprises Mg.

[0301] Embodiment 76 provides the method of any one of Embodiments 1-75, wherein the cathode comprises Cu and the anode comprises Al.

[0302] Embodiment 77 provides a method of any one of embodiments 1-76, wherein the cathode comprises a planar frame of the galvanic cell and a cathode material contained within the periphery of the frame, wherein the cathode material is electrically connected to the frame, wherein the cathode material contained within the periphery of the frame comprises a porous cathode material.

[0303] Embodiment 78 provides the method of any one of embodiments 1-77, comprising

[0304] immersing one or more of the galvanic cells in a housing containing water;

[0305] Phosphorus-containing salts are filtered from the treated water through one or more filters at least partially submerged in the water in which the galvanic cell is immersed.

[0306] Embodiment 79 provides the method of any one of embodiments 1-78, wherein:

[0307] The cathode of the galvanic cell comprises a planar frame of the galvanic cell having a polygonal perimeter and a porous material contained within the perimeter of the frame, the porous material being a wire mesh or a wire screen in direct contact with the frame; and

[0308] The planar frame includes a plurality of anodes fastened to the frame, and a plurality of conductive connectors electrically connecting the anodes and cathodes, the conductive connectors comprising Cu, Zn, Fe, Cd, Ni, Sn, Pb, or a combination thereof;

[0309] wherein each anode is a strip fastened to a planar frame at two opposing edges of the planar frame on a face of the frame, wherein each of the anodes is fastened to the planar frame at each of the two edges of the planar frame using at least one of the conductive connectors such that each of the anodes on the face is substantially parallel to each other on the face and spans a porous material contained within the perimeter of the planar frame, forming a gap between the porous material contained within the perimeter of the planar frame and the anode strips, wherein each anode directly contacts the planar frame at each of the edges of the planar frame, wherein the anodes are fastened to the planar frame via at least one conductive connector, wherein a plurality of anodes are spaced apart across the face such that they are not in physical contact with each other, and wherein the gap is about 1 mm to about 110 mm.

[0310] Embodiment 80 provides the method of any one of embodiments 1-79, wherein:

[0311] The water in which the galvanic cell is immersed has a pH of about 5 to about 7;

[0312] Phosphorus-containing salts formed in the galvanic dephosphorization process include

[0313] AlPO4 or a hydrate thereof, the AlPO4 comprising phosphorus and Al from the anode,

[0314] Aluminum hydroxide or a hydrate thereof, the aluminum hydroxide containing Al from the anode, or

[0315] their combination;

[0316] The anode of the galvanic cell comprises Al, wherein the anode is about 90 wt % to about 100 wt % Al;

[0317] The cathode of the galvanic cell comprises Cu, wherein the cathode is about 90 wt % to about 100 wt % Cu; and the galvanic cell comprises a conductive connector electrically connecting the anode and cathode, the conductive connector comprising an alloy comprising Cu and Zn.

[0318] Embodiment 81 provides the method of any one of embodiments 1-79, wherein:

[0319] The water in which the galvanic cell is immersed has a pH of about 10 to about 11;

[0320] Phosphorus-containing salts formed in the galvanic dephosphorization process include

[0321] Magnesium phosphate, magnesium potassium phosphate, their hydrates or their combinations,

[0322] NH4MgPO4 or a hydrate thereof, the NH4MgPO4 comprising phosphorus and Mg from the anode,

[0323] Mg(OH)2 comprising magnesium from said anode, or

[0324] their combination;

[0325] The anode of the galvanic cell comprises Mg, wherein the anode is from about 90 wt % to about 100 wt % Mg;

[0326] The cathode of the galvanic cell comprises Cu, wherein the cathode is about 90 wt % to about 100 wt % Cu; and the galvanic cell comprises a conductive connector electrically connecting the anode and cathode, the conductive connector comprising an alloy comprising Cu and Zn.

[0327] Embodiment 82 provides the method of any one of Embodiments 1-81, further comprising further removing nitrogen from the water produced by the galvanic phosphorus removal stage.

[0328] Embodiment 83 provides the method of embodiment 82, wherein further removing nitrogen comprises exposing the water to denitrifying bacteria to convert water-soluble nitrogen therein to nitrogen gas that is removed.

[0329] Embodiment 84 provides the method of any one of Embodiments 82-83, comprising deoxygenating the water prior to further removing nitrogen therefrom.

[0330] Embodiment 85 provides the method of any of Embodiments 82-84, comprising oxidizing or hydrolyzing at least some of the nitrogen in the water to form nitrates prior to further removing the nitrogen therefrom.

[0331] Embodiment 86 provides the method of any of Embodiments 82-85, comprising reoxygenating the water after further removing nitrogen therefrom.

[0332] Embodiment 87 provides the method of any one of embodiments 1-86, further comprising further removing nitrogen from the water produced by the galvanic phosphorus removal section, the further removing nitrogen comprising:

[0333] optionally oxidizing or hydrolyzing at least some of the nitrogen in the water to form nitrates;

[0334] optionally deoxygenating the water to an oxygen concentration of about 0 ppm to about 0.3 ppm;

[0335] exposing the water to denitrifying bacteria immobilized on a porous substrate to convert nitrates in the water into nitrogen gas which is removed and forms denitrified water;

[0336] optionally reoxygenating the denitrified water to an oxygen concentration of about 1 ppm to about 20 ppm;

[0337] wherein the denitrified water has a total nitrogen concentration of about 0.0 ppm to about 2 ppm total nitrogen.

[0338] Embodiment 88 provides a method for removing phosphorus and nitrogen from water, the method comprising:

[0339] The starting feed water containing nitrogen and phosphorus is passed through a phosphorus removal section with an elevated pH, comprising

[0340] Raising the pH of the water to between 8.5 and 9.5 using one or more bases to precipitate a phosphate salt from the water, the phosphate salt comprising ammonium magnesium phosphate, calcium phosphate, or a combination thereof; and

[0341] Removing precipitated phosphate salts from the water, wherein the elevated pH phosphorus removal stage removes 90-98% of the active phosphorus in the water;

[0342] The water is passed through an electrolytic denitrification process, including

[0343] Passing water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas, the electrolytic cell comprising a cathode comprising stainless steel and an anode comprising titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti), wherein passing the water through the electrolytic denitrification section removes 80-100% of the ammonia from the water; and

[0344] Pass the water through the galvanic dephosphorization section, including

[0345] immersing the galvanic cell in water to form treated water containing a salt containing phosphorus from the water, the salt comprising AlPO4 or a hydrate thereof, the AlPO4 containing phosphorus and Al from the anode,

[0346] Aluminum hydroxide or a hydrate thereof, the aluminum hydroxide containing Al from the anode, or

[0347] their combination;

[0348] The primary battery comprises

[0349] an anode comprising Al, wherein the anode is from about 90 wt % to about 100 wt % Al,

[0350] a cathode comprising Cu, wherein the cathode is from about 90 wt % to about 100 wt % Cu,

[0351] a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising an alloy comprising Cu and Zn;

[0352] separating the phosphorus-containing salt from the treated water;

[0353] wherein the water produced by the method has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw material water, wherein the water produced by the method has

[0354] A total phosphorus concentration of about 0.0001 ppm to 0.05 ppm, and

[0355] A total nitrogen concentration of about 0 ppm to about 1 ppm.

[0356] Embodiment 89 provides a method for removing nitrogen from water, the method comprising: passing the water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas.

[0357] Embodiment 90 provides the method of embodiment 89, wherein the water has a chloride concentration of 50 ppm to 40,000 ppm prior to passing through the electrolytic cell.

[0358] Embodiment 91 provides the method of any of Embodiments 89-90, wherein the water has a chloride concentration of 200 ppm to 10,000 ppm prior to passing through the electrolytic cell.

[0359] Embodiment 92 provides the method of any one of Embodiments 89-91, wherein the water is passed through a plurality of electrolytic cells.

[0360] Embodiment 93 provides the method of any one of Embodiments 89-92, wherein passing water through the electrolytic cell comprises partially immersing the electrolytic cell in water.

[0361] Embodiment 94 provides the method of any one of Embodiments 89-93, wherein passing water through the electrolytic cell comprises completely immersing the electrolytic cell in water.

[0362] Embodiment 95 provides the method of any of Embodiments 89-94, further comprising applying shear to the water as it passes through the electrolytic cell.

[0363] Embodiment 96 provides the method of any of Embodiments 89-95, wherein water is passed around and between the anode and cathode of the electrolytic cell.

[0364] Embodiment 97 provides the method of any one of Embodiments 89-96, wherein the water passed through the electrolytic cell has a pH of 6 to 12.

[0365] Embodiment 98 provides the method of any one of embodiments 89-97, wherein the water passed through the electrolytic cell has a pH of 6 to 7.

[0366] Embodiment 99 provides the method of any one of Embodiments 89-98, further comprising adding one or more bases to the water to adjust the pH of the water contacting the electrolytic cell.

[0367] Embodiment 100 provides the method of any one of embodiments 89-99, comprising operating the electrolytic cell with a direct current.

[0368] Embodiment 101 provides the method of any one of Embodiments 89-100, comprising operating the electrolytic cell with an alternating current.

[0369] Embodiment 102 provides the method of any of Embodiments 89-101, comprising operating the electrolytic cell at a current density of 0.001-0.1 A / cm2.

[0370] Embodiment 103 provides the method of any one of embodiments 89-102, comprising: 2 The electrolytic cell was operated at a current density of 10 Å.

[0371] Embodiment 104 provides the method of any of Embodiments 89-103, wherein the electrolytic cell comprises an anode and a cathode having a spacing therebetween of 0.5-8 mm.

[0372] Embodiment 105 provides the method of any of Embodiments 89-104, wherein the electrolytic cell comprises an anode and a cathode having a spacing of 2-4 mm therebetween.

[0373] Embodiment 106 provides the method of any of Embodiments 89-105, wherein the electrolytic cell comprises a cathode comprising titanium, stainless steel, or a combination thereof.

[0374] Embodiment 107 provides the method of any of Embodiments 89-106, wherein the electrolytic cell comprises a cathode comprising stainless steel.

[0375] Embodiment 108 provides the method of any one of Embodiments 89-107, wherein the electrolytic cell includes an anode comprising

[0376] Titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti), or

[0377] Titanium oxide and ruthenium oxide supported on titanium (TiO2-RuO2 / Ti), or

[0378] Titanium and platinum (Ti-Pt), or

[0379] A combination of them.

[0380] Embodiment 109 provides the method of any one of Embodiments 89-108, wherein removing the nitrogen in the form of nitrogen gas comprises converting ammonia in the water into nitrogen gas using the electrolytic cell.

[0381] Embodiment 110 provides the method of any of Embodiments 89-109, wherein the water is passed through an electrolytic denitrification stage to produce hypochlorite, which reacts with ammonia in the water to form nitrogen gas.

[0382] Embodiment 111 provides the method of any of Embodiments 89-110, further comprising releasing the nitrogen to the atmosphere.

[0383] Embodiment 112 provides the method of any of Embodiments 89-111, wherein passing the water through an electrolytic denitrification stage removes 80-100% of the ammonia from the water.

[0384] Embodiment 113 provides the method of any one of Embodiments 89-112, wherein passing the water through an electrolytic denitrification stage removes 99-100% of the ammonia from the water.

[0385] Embodiment 114 provides the method of any one of embodiments 89-113, wherein the water is passed through an electrolytic denitrification stage to remove 0.1-90% of the active phosphorus from the water.

[0386] Embodiment 115 provides the method of any one of embodiments 89-114, wherein the water is passed through an electrolytic denitrification stage to remove 1-30% of the active phosphorus from the water.

[0387] Embodiment 116 provides the method of any of Embodiments 89-115, wherein the electrolytic cell produces 100-20,000 ppm hypochlorite from chloride in water.

[0388] Embodiment 117 provides the method of any of Embodiments 89-116, wherein the electrolytic cell produces 2000-2500 ppm hypochlorite from chloride in water.

[0389] Embodiment 118 provides the method of any one of embodiments 89-117, wherein:

[0390] wherein water is passed through an electrolytic denitrification stage to produce hypochlorite, which reacts with ammonia in the water to form nitrogen;

[0391] The cathode comprises stainless steel;

[0392] The anode comprises titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti); and

[0393] Passing the water through an electrolytic denitrification stage removes 80-100% of the ammonia from the water.

[0394] Embodiment 119 provides a method for removing nitrogen from water, the method comprising:

[0395] The water is passed through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas, the electrolytic cell comprising a cathode comprising stainless steel and / or titanium and an anode comprising

[0396] Titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti), or

[0397] Titanium oxide and ruthenium oxide supported on titanium (TiO2-RuO2 / Ti), or

[0398] Titanium and platinum (Ti-Pt), or

[0399] their combination;

[0400] The removal of nitrogen in the form of nitrogen gas removes 80-100% of the ammonia from the water.

[0401] Embodiment 120 provides a system for removing nitrogen and phosphorus from water, the system comprising:

[0402] a pH-raising phosphorus removal section configured to raise the pH of the starting raw water to greater than or equal to 7.5 to precipitate phosphorus salts from the water and to remove the precipitated phosphorus salts from the water;

[0403] an electrolytic denitrification section, the electrolytic denitrification section comprising an electrolytic cell configured to remove nitrogen from water in the form of nitrogen gas; and

[0404] A galvanic phosphorus removal section, the galvanic phosphorus removal section comprising a galvanic cell, the galvanic cell comprising an anode, the anode comprising Mg, Al, Fe, Zn or a combination thereof; and a cathode having a composition different from that of the anode, the cathode comprising Cu, Ni, Fe or a combination thereof; the galvanic cell is configured to form treated water comprising a salt, the salt comprising phosphorus from the water, wherein the galvanic phosphorus removal section is configured to separate the phosphorus-containing salt from the treated water;

[0405] The water produced by the system has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw water.

[0406] Embodiment 121 provides a device for removing nitrogen from water, the device comprising:

[0407] An electrolytic cell through which water is configured to flow to remove nitrogen from the water in the form of nitrogen gas, the electrolytic cell comprising a cathode comprising stainless steel and an anode comprising

[0408] Titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti), or

[0409] Titanium oxide and ruthenium oxide supported on titanium (TiO2-RuO2 / Ti), or

[0410] Titanium and platinum (Ti-Pt), or

[0411] their combination;

[0412] The removal of nitrogen in the form of nitrogen gas removes 80-100% of the ammonia from the water.

[0413] Embodiment 122 provides a method, system or apparatus of any one or any combination of embodiments 1-121, optionally configured so that all of the listed elements or options are available for use or selection therefrom.

Claims

1. A method for removing phosphorus and nitrogen from water, the method comprising: The starting raw water containing nitrogen, phosphorus and chloride is passed through a phosphorus removal section with an elevated pH, comprising raising the pH of the water to greater than or equal to 7.5 to precipitate phosphate salts from the water; and removing precipitated phosphate salts from said water; The water is passed through an electrolytic denitrification section, comprising passing the water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas; wherein removing the nitrogen in the form of nitrogen gas comprises converting ammonia in the water into nitrogen gas using the electrolytic cell, wherein passing the water through the electrolytic nitrogen removal section produces hypochlorite, which reacts with ammonia in the water to form nitrogen gas; and The water is passed through a galvanic dephosphorization section, including immersing a galvanic cell in the water to form treated water comprising a salt comprising phosphorus from the water, the galvanic cell comprising An anode comprising Al, a cathode having a different composition than the anode, the cathode comprising Cu; wherein no external potential is applied across the anode and cathode; and separating the phosphorus-containing salt from the treated water, wherein the phosphorus-containing salt comprises AlPO 4 or a hydrate thereof, the AlPO 4 comprising the phosphorus and Al from the anode; The water produced by the method has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw material water.

2. The method of claim 1, wherein the starting raw water is water derived from a process of dissolving phosphate-containing rocks to produce phosphoric acid. 3 . The method according to claim 1 , wherein the starting raw material water has a chloride concentration of 200 ppm to 10,000 ppm.

4. The method of claim 1, wherein the water produced by the method has a total phosphorus concentration, dissolved phosphorus concentration, active phosphorus concentration, or a combination thereof of 0.0001 ppm to 0.1 ppm, and a total nitrogen concentration, dissolved nitrogen concentration, or a combination thereof of 0 ppm to 1 ppm.

5. The method of claim 1, wherein raising the pH of the water to precipitate phosphate salts from the water comprises raising the pH of the water to a range of 8.5 to 9.

5.

6. The method of claim 1, wherein the precipitated phosphate salt comprises magnesium ammonium phosphate, calcium phosphate, or a combination thereof.

7. The method of claim 1, wherein the electrolytic cell comprises a cathode comprising titanium, stainless steel, or a combination thereof.

8. The method of claim 1, wherein the electrolytic cell comprises an anode comprising: Titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti), or Titanium oxide and ruthenium oxide supported on titanium (TiO2-RuO2 / Ti), or Titanium and platinum (Ti-Pt), or A combination of them.

9. The method according to claim 1, wherein: The water in which the galvanic cell is immersed has a pH of 5 to 7; The phosphorus-containing salt formed in the galvanic dephosphorization section includes AlPO4 or its hydrate, and the AlPO4 contains the phosphorus and Al from the anode; The anode of the galvanic cell comprises Al, wherein the anode is 90 wt % to 100 wt % Al; The cathode of the galvanic cell comprises Cu, wherein the cathode is 90 wt % to 100 wt % Cu; and The galvanic cell includes a conductive connector electrically connecting the anode and the cathode, the conductive connector including an alloy including Cu and Zn.

10. The method according to claim 1, further comprising further removing nitrogen from the water produced by the galvanic phosphorus removal section.

11. A method for removing phosphorus and nitrogen from water, the method comprising: The starting feed water containing nitrogen and phosphorus is passed through a phosphorus removal section with an elevated pH, comprising raising the pH of the water to between 8.5 and 9.5 using one or more bases to precipitate phosphate salts from the water, The phosphate salt includes magnesium ammonium phosphate, calcium phosphate or a combination thereof; and removing precipitated phosphate salts from the water, wherein the elevated pH phosphorus removal stage removes 90-98% of the active phosphorus in the water; The water is passed through an electrolytic denitrification section, comprising passing the water through an electrolytic cell to remove nitrogen from the water in the form of nitrogen gas, the electrolytic cell comprising a cathode comprising stainless steel and an anode comprising titanium oxide, ruthenium oxide, and iridium oxide supported on titanium (TiO2-RuO2-IrO2 / Ti), wherein passing the water through the electrolytic denitrification section removes 80-100% of the ammonia from the water; wherein removing nitrogen as nitrogen gas comprises converting ammonia in the water into nitrogen gas using the electrolytic cell, wherein passing the water through the electrolytic denitrification section produces hypochlorite, which reacts with ammonia in the water to form nitrogen gas; and The water is passed through a galvanic dephosphorization section, including immersing a galvanic cell in the water to form treated water containing a salt, the salt containing phosphorus from the water, the salt containing phosphorus comprising AlPO4 or a hydrate thereof, the AlPO4 containing the phosphorus and Al from the anode; The primary battery comprises an anode comprising Al, wherein the anode is 90 wt % to 100 wt % Al, A cathode comprising Cu, wherein the cathode is 90 wt % to 100 wt % Cu, a conductive connector electrically connecting the anode and the cathode, the conductive connector comprising an alloy comprising Cu and Zn, wherein no external potential is applied across the anode and cathode; separating said salt comprising phosphorus from said treated water; wherein the water produced by the method has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw material water, wherein the water produced by the method has 0.0001 ppm to 0.05 ppm total phosphorus concentration, and 0ppm to 1ppm total nitrogen concentration.

12. A system for removing nitrogen and phosphorus from water by performing the method of claim 1, the system comprising: a pH-raising phosphorus removal section configured to raise the pH of the starting raw water to greater than or equal to 7.5 to precipitate phosphorus salts from the water and to remove the precipitated phosphorus salts from the water; an electrolytic denitrification section, the electrolytic denitrification section comprising an electrolytic cell configured to remove nitrogen from the water in the form of nitrogen gas; and a galvanic phosphorus removal section, the galvanic phosphorus removal section comprising a galvanic cell, the galvanic cell comprising an anode, the anode comprising Al; and a cathode having a different composition than the anode, the cathode comprising Cu; wherein no potential is applied across the anode and the cathode, the galvanic cell is configured to form treated water comprising a salt, the salt comprising phosphorus from the water, wherein the galvanic phosphorus removal section is configured to separate the salt comprising phosphorus from the treated water; Wherein the water produced by the system has a lower phosphorus concentration and a lower nitrogen concentration than the starting raw material water.

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