Electrochemical production of a metal based treatment agent for water treatment

Abstract

The present disclosure describes methods and systems for water treatment by an iron-based coagulant water treatment agent. The water treatment agent is produced by an electrochemical cell in fluid communication with the water treatment system. The water treatment agent comprises MxOy(OH)z, wherein M represents a metal, wherein x is larger than 0, and y and / or z is greater than zero.

Description

WSGR Docket No. 71441-701.601ELECTROCHEMICAL PRODUCTION OF A METAL BASED TREATMENT AGENT FOR WATER TREATMENTCROSS-REFERENCE

[0001] This application claims the benefit of Application No. N2038406 filed August 7, 2024 at the Netherlands Patent Office, The Hague, which is incorporated by reference herein in its entirety.BACKGROUND

[0002] Water treatment may be employed to aid in the worldwide problem of water scarcity. It may be used to make water suitable for a specific purpose or objective. For instance, ground water may be treated for the production of drinking water and wastewater may be treated to be suitable for environmental discharge.

[0003] Water treatment systems are designed to remove impurities from aqueous solutions. Safe, clean water is an important resource. There exists a need for methods and systems for water treatment that purify water sources without adding high levels of salt, as chloride ions, while reducing energy consumption, and improving sustainability and efficiency.SUMMARY

[0004] Described herein are such methods and systems for water treatment. The methods and systems described herein may produce a coagulant (e.g., water treatment agent) to remove impurities from water treatment fluid streams. The water treatment agent may be produced on site to the water treatment system, thereby reducing transport and manufacturing costs. The water treatment agent may be produced external to a water treatment fluid source, which may improve efficiency and reduce fouling. Additionally, the methods and systems described herein may enable lower amounts of chloride ions in treated water streams, which positively improves the quality of treated water streams without compromise impurity removal.

[0005] In one aspect, the present disclosure provides a method for producing a water treatment agent in parallel to a water treatment system. In some cases, the method comprises providing an electrochemical cell comprising at least one sacrificial electrode, at least one counter electrode, and an electrolyte fluid comprising feed water. In some cases, said sacrificial electrode comprises iron. In some cases, the method further comprises applying a current between said at least one sacrificial electrode and said at least one counter electrode to form said water treatment agent in a product stream. In some cases, said product stream is fluidically connected to said water treatment system. In some cases, said water treatment agent comprises MxOy(OH)z, wherein M represents a metal, x is larger than 0, and (i) y is greater than zero and / or z is greater than zero. In some cases, the water treatment agent comprises iron. In some cases, the chemical formula of the water treatment agentWSGR Docket No. 71441-701.601 comprises M representing iron (Fe). In some cases, said feed water is a fraction from an influent water stream of said water treatment system, and / or a fraction from an effluent water stream of said water treatment system. In some cases, said feed water is from a sourced water stream external to said water treatment system. In some cases, said treatment agent has a concentration in said product stream of at least about 250 mg / L. In some cases, said treatment agent has a concentration in said product stream of at least about 500 mg / L. In some cases, said treatment agent has a concentration in said product stream of at least about 1000 mg / L. In some cases, said feed water comprises about 0.005% to about 10% of said influent water stream or said effluent water stream of said water treatment system. In some cases, a total fluid flow through said electrochemical cell comprises between about 0.05 vol% to about 5 vol% of a total flow of an effluent stream of said water treatment system. In some cases, said treatment agent comprises a ratio of chloride to iron of less than 3:1. In some cases, said treatment agent comprises a ratio of inorganic anions from one or more strong acids to metal valence state of less than L l.In some cases, said metal is iron, and said treatment agent comprises a ratio of inorganic anions from one or more strong acids to iron valence state of less than 1 : 1. In some cases, said inorganic anions from one or more strong acids comprise chloride ions. In some cases, said inorganic anions from one or more strong acids comprise sulfate ions. In some cases, said inorganic anions form one or more strong acids comprise chloride ions and sulfate ions. In some cases, said chloride ions and said sulfate ions are in a ratio between 4:1 and 1 :4. In some cases, said product stream comprising said treatment agent has at least a 10% reduction of chloride ions than an equivalent iron dosage from iron chloride salts, or a solution thereof. In some cases, the method further comprises directing said intermediate water stream to a water treatment step. In some cases, said feed water comprises 0.005 to 10 vol% of the effluent water stream, based on the total volume of the effluent water stream. In some cases, said feed water comprises 0.05 to 5 vol% of the effluent water stream, based on the total volume of the effluent water stream. In some cases, said feed water comprises 0.01 to 1 vol% of the effluent water stream, based on the total volume of the effluent water stream. In some cases, said electrolyte has a conductivity of at least 1000 pS / cm. In some cases, said electrolyte has a conductivity of at least 1500 pS / cm. In some cases, said electrolyte has a conductivity of at least 2000 pS / cm. In some cases, the method further comprises increasing the conductivity of the electrolyte by one or more of (i) introduction of one or more conductivity enhancers in the feed water, (ii) by plasma treatment, (iii) by pH adjustment and (iv) increasing a temperature of the feed water. In some cases, a conductivity enhancer of said one or more conductivity enhancers is chloride-based. In some cases, said chloride-based conductivity enhancer comprises sodium chloride or potassium chloride. In some cases, said pH adjustment comprises providing hydrochloric acid. In some cases, the methodWSGR Docket No. 71441-701.601 further comprises leading said product stream to a separator to at least partially separate said water treatment agent from said electrolyte fluid. In some cases, the method further comprises mixing said product steam with a water fluid stream of said water treatment system. In some cases, said electrolyte fluid is at least partially separated from said water treatment agent prior to said providing said treatment agent to said water treatment system. In some cases, the method further comprises recycling at least part of said electrolyte fluid into said electrochemical cell. In some cases, the method further comprises leading said product stream and a processing water stream into a dosing chamber, wherein said processing water stream is a fraction of said influent water stream, said effluent water stream, and / or other sourced water stream, and wherein said dosing chamber is downstream from said separator. In some cases, said water stream has a pH of less than 7.

[0006] In some cases, said water stream comprises hydrochloric acid. In some cases, the method further comprises processing said water treatment agent before introducing said product stream into said influent water stream, wherein said processing comprises aeration and / or oxygen injection. In some cases, the method further comprises generating or collecting hydrogen gas from said electrochemical cell and leading said hydrogen gas to a fuel cell to generate electricity. In some cases, said electricity is employed for applying said current in said electrochemical cell. In some cases, said current is in the range of 0.5 to 15 kAV / kg metal. In some cases, said current is in the range of 1 to 12 kAV / kg metal.

[0007] In another aspect, the present disclosure provides a water treatment system comprising an electrochemical cell configured to produce a water treatment agent, wherein said electrochemical cell comprises at least one sacrificial electrode, at least one counter electrode, and an electrolyte fluid comprising water, wherein said sacrificial electrode comprises iron, wherein said electrochemical cell is fluidically connected to a water treatment stream of said water treatment system, and wherein a product stream from said electrochemical cell comprises said water treatment agent with the chemical formula MxOy(OH)z, wherein M represents a metal, x is larger than 0, and (i) y is greater than zero or z is greater than zero.

[0008] Additional aspects and advantages of the present disclosure will become readily apparent to those skilled in this art from the following detailed description, wherein only illustrative embodiments of the present disclosure are shown and described. As will be realized, the present disclosure is capable of other and different embodiments, and its several details are capable of modifications in various obvious respects, all without departing from the disclosure. Accordingly, the drawings and description are to be regarded as illustrative in nature, and not as restrictive.WSGR Docket No. 71441-701.601BRIEF DESCRIPTION OF THE DRAWINGS

[0009] The novel features of the present disclosure are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present disclosure will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the present disclosure are utilized, and the accompanying drawings (also “Figure” and “FIG.” herein), of which:

[0010] FIG. 1 illustrates a system for producing a water treatment agent comprising an electrochemical cell, in accordance with some embodiments described herein.

[0011] FIG. 2 illustrates a system for producing a water treatment agent comprising an electrochemical cell and a conductivity enhancer, in accordance with some embodiments described herein.

[0012] FIG. 3 illustrates a system for producing a water treatment agent comprising an electrochemical cell wherein a product stream is led to a separator, in accordance with some embodiments described herein.

[0013] FIG. 4 illustrates a system for producing a water treatment agent comprising an electrochemical cell and a dosing chamber, in accordance with some embodiments described herein.

[0014] FIG. 5 illustrates a system for producing a water treatment agent comprising an electrochemical cell and a fuel cell, in accordance with some embodiments described herein.

[0015] FIG. 6 illustrates a system for producing a water treatment agent comprising an electrochemical cell, a conductivity enhancer, a dosing chamber, and a fuel cell, in accordance with some embodiments described herein.

[0016] FIG. 7 illustrates phosphate impurities concentration against iron dose in accordance with some embodiments described herein.

[0017] FIG. 8 illustrates phosphate impurities concentration against iron dose in accordance with some embodiments described herein.

[0018] FIG. 9 illustrates phosphate impurities concentration against iron dose in accordance with some embodiments described herein.

[0019] FIG. 10 illustrates phosphate impurities concentration against iron dose in accordance with some embodiments described herein.

[0020] FIG. 11 illustrates dissolved organic carbon species concentration in accordance with examples described herein.

[0021] FIG. 12 illustrates examples of sludge treatment dry solid content in accordance with some examples described herein.WSGR Docket No. 71441-701.601

[0022] FIG. 13 illustrates resulting data of removal of arsenic by a water treatment agent described herein, compared to an iron chloride salt.DETAILED DESCRIPTION

[0023] The invention is in the field of water treatment. In particular, the present invention is directed to a method for producing a water treatment agent external (e.g., in parallel) of a water treatment system. The method comprising providing an electrochemical cell. The present invention is further directed to an electrochemical cell for use in the method and to a water treatment system for the method comprising the electrochemical cell. The methods and systems described herein may be used to produce a water treatment agent “in parallel” to a water treatment plant. As used herein, “in parallel” may generally refer to a location proximal to a fluid stream of a water treatment system, but not within (in-situ) of that fluid stream. In some cases, in parallel may refer to being fluidically connected to a fluid stream of a water treatment system. In some cases, in parallel may mean that the water treatment agent is not required to be moved by external means after production. The water treatment agent may also be produced within a stream that is sealed from an exterior environment to the water treatment system, which may reduce the likelihood of spills or dependency on performance and stability of the water treatment system. In parallel may also mean peripherally to the water treatment system. Additional benefits of producing the water treatment agent in parallel to the water treatment system are described herein. The terms water treatment agent and treatment agent are herein used interchangeably.

[0024] As used herein, the term “water treatment stream” and “water treatment system” or a fluid stream thereof may refer generally to a system for treating water by removing impurities and other dissolved and insoluble species. As used herein, the water treatment system may refer to the point of removal of impurities at macro scale. For example, the water treatment stream may be the water stream comprising impurities that is treated with the water treatment agent described herein.

[0025] As used herein, the term “coagulant” may refer generally to the water treatment agent that coagulates one or more impurities from the water treatment stream. The one or more impurities may comprise phosphate species or dissolved organic carbon species. Alternatively, or in addition, the one or more impurities may comprise one or more of arsenic, sulfide species, and pigmentation (e.g., turbidity).

[0026] As used herein, the term “flocculant” may refer generally to a species added to a water treatment fluid stream to aggregate flocks of coagulated impurities.

[0027] Background of water treatment

[0028] Water treatment systems may encompass multiple treatment steps, i.e. stages and methods. Examples of such stages and methods may include sedimentation, filtration, aeration, flotation,WSGR Docket No. 71441-701.601 disinfection adsorption and / or coagulation. Other examples of relevant stages and methods relate to sludge treatment, generally a core component of the water treatment system. With sludge being generated during treatment steps, as sedimentation, flotation, and filtration, processing of this sludge may be directly connected to the water treatment system. Sludge treatment typically includes sludge thickening and / or dewatering. Examples of such methods include gravitational thickening, membrane press and centrifuge.

[0029] Coagulation is a term generally used in the art to describe adding chemicals, also referred to as coagulants, to water. These coagulants aid in clumping (soluble) impurities, that may later be removed by filtration, flotation and / or sedimentation. The impurities in water are typically electrically charged, with charges being neutralized by coagulants allowing the impurities to form aggregates. Flocculation may be a subsequent process used in water treatment following coagulation. It might involve the addition of chemicals called flocculants to water, assisting in aggregating the small particles, formed during coagulation, into larger clusters known as flocs. The gentle mixing of water promotes these particles to collide and stick together, forming flocs that are large enough to be removed by filtration or sedimentation. While the process of adsorption and / or absorption is different from coagulation and flocculation, it shares similarities from a practical perspective. In adsorption, a (soluble) impurity is attached to the surface of a particle (adsorbent) and so removed from the water matrix. This impurity can subsequently be incorporated into the particle (molecular) matrix, known as absorption. Absorption can also take place during the coagulation-flocculation process, with impurities being incorporated in the formed solids (aggregates).

[0030] Chemicals in water treatment

[0031] An example of chemicals used for coagulation, flocculation, adsorption and / or absorption processes, may be metal salts, including aluminum sulfate, ferric chloride, ferric sulfate and polyaluminum chloride. However, disadvantageously, the carbon footprint for producing the metal salts is high. Accordingly, the ambition of the water sector, including drinking, waste and industry water, to reduce their CO2 emissions conflicts with the high CO2 footprint of essential water treatment chemicals, like inorganic coagulants. Other disadvantages of these metal salts are related to chemical safety, ineffective bulk transport, and unwanted acidification and high salt introduction. For instance, many of these chemicals are strongly acidic and can cause skin irritation and environmental damage. Additionally, a large volume of a metal salt solution may be typically required, due to the presence of inorganic anions from strong acids as chloride and sulphate, resulting in ineffective transport. Recognized herein are methods and systems for production of a water treatment agent (e.g., a flocculant) that can be produced on site and external from a waterWSGR Docket No. 71441-701.601 treatment fluid stream. These methods and systems described herein may address or obviate the above issues of other water treatment solutions.

[0032] Electrocoagulation

[0033] In contrast to electrocoagulation within the water treatment system, the present methods and systems may provide greater scalability, lower energy consumption, and lower capital and operating costs. For example, producing the water treatment agent in a fluid stream separate from, but fluidically connected to the water treatment stream, may allow the environment of the electrochemical cell to produce higher efficiency of the water treatment agent without interference from the impurities to be removed from the water treatment system. The efficiency in producing the water treatment agent in the present system may be higher due to a reduction in passivation of the electrodes. Passivation may be caused by interaction of the electrochemical cell with water impurities, as nitrate, phosphate, sulphate, calcium and magnesium, present in the water to be treated. By producing the water treatment agent in parallel to the water treatment stream comprising these impurities, passivation of the electrodes is reduced.

[0034] It is an object of the present inventors to provide an improved method that at least partially provides the above referenced benefits. The inventors surprisingly found a method that allows for a sustainable, accurate and effective production of a treatment agent, specifically an iron (metal) based treatment agent, for use in water treatment. The treatment agent may advantageously be produced externally of (e.g., in parallel to) the water treatment. Furthermore, the method may advantageously allow for a continuous production of the treatment agent. The produced treatment agent typically has similar functionalities as conventional metal salts and / or other sorbents, besides, the method of producing this water treatment agent may allow for the ‘dosing’ principle of conventionally used water treatment chemicals (e.g., iron chloride salts and solutions thereof) without the negative effects of high chloride ions in the treated water stream. The method advantageously has a low carbon footprint and low energy consumption. Additionally, this water treatment agent has the possibility to significantly lower the introduction of inorganic anions from strong acids, as chloride and / or sulphate, also referred to as ‘salt-based anions’. Compared to conventional metal salts, where a metal (Fe2+, Fe3+, or A13+) is ‘ionized’, i.e. the positive charge of the metal is fully neutralized by salt-based anions (Cl- and SO42-), the water treatment agent has a reduced salt-based anion presence.

[0035] In a first aspect, the present invention provides a method for producing a water treatment agent. The water treatment agent may be formed externally (e.g., in parallel) of a water treatment system. The water treatment agent may be produced on the site of, or in close proximity to, a water treatment plant. The water treatment system (e.g., water treatment plant) may comprise one orWSGR Docket No. 71441-701.601 more water treatment steps. Producing the water treatment agent onsite may reduce or minimize transportation and accordingly, energy, supply chain risks and CO2 emissions. It may also increase safety. Producing the water treatment agent may comprise providing an electrochemical cell. The electrochemical cell may comprise a first electrode and a second electrode. The first electrode may be a sacrificial electrode. The sacrificial electrode may be consumed (e.g., oxidized) by a chemical reaction to produce the water treatment agent (coagulant). The second electrode may be a counter electrode. The counter electrode may not be a sacrificial electrode. In some cases, the electrochemical cell comprises two or more sacrificial electrodes. In some cases, the electrochemical cell may comprise two or more counter electrodes. In some cases, the electrochemical cell may comprise 2, 3, 4, 5, 6, 7, 8, 9, 10, 15, 20, 30, 40, 50, 75, 100 or more electrodes. By producing the water treatment agent on site of the water treatment plant, only the electrodes may need to be transported to the site, rather than the bulk of the water treatment agent and carrying solution. Since the consumables are generally solids, it also enables users to have increased inventory with easier storage. Additionally, the method of producing the water treatment agent in parallel may be continuous.

[0036] The method comprises providing an electrochemical cell comprising at least one sacrificial iron-comprising electrode, at least one counter electrode, and an electrolyte fluid comprising feed water. The electrolyte fluid may comprise one or more salts or ions and water. The method further comprises applying a current between the sacrificial electrode and counter electrode to generate the water treatment agent in a product stream.

[0037] The water treatment agent may be in the form of an iron (oxy)hydroxide. The product stream may be fluidically connected to the water treatment system.

[0038] Electrode and connections

[0039] As used herein, the term ‘sacrificial electrode’ refers to electrode behavior where the electrode is at least partially consumed, i.e. dissolved, during operation of the method, and accordingly during the application of a current on the electrode. Due to the at least partial consumption of the electrode, the treatment agent may be generated.

[0040] The sacrificial and / or counter electrode may comprise a metal. The metal may be one or more metals selected from the group consisting of aluminum, iron, zinc, copper, nickel, lead, tin, magnesium, and cobalt. It was found that particularly good results may be obtained if the sacrificial and / or counter electrode, preferably at least the sacrificial electrode, comprises aluminum and / or iron, preferably iron.

[0041] The structure of the sacrificial and / or counter electrode may be one or more shapes. For example, the electrode may be a flat plate electrode, a cylindrical electrode, a rod electrode, a gridWSGR Docket No. 71441-701.601 electrode, a mesh electrode, a disk electrode and / or a wire electrode. If two or more electrodes are employed, each electrode may individually and independently have a particular structure. For maintenance and costs purposes, flat plate electrodes may be preferred.

[0042] Electrode is herein used to refer to the sacrificial and / or counter electrode, unless specifically indicated otherwise. The counter electrode may show inert behavior. In contrast to the sacrificial electrode, an inert electrode is not substantially dissolved during operation.

[0043] The electrodes of the electrochemical cell may be placed in a range of electrical connections, wherein at least one electrode, preferably an electrode on the outer side (i.e. closest to a wall of the electrochemical cell) may be connected to a (temporal) negative terminal. The electrode on the opposite side (i.e. closest to the opposite wall of the electrochemical cell) may be connected to a (temporal) positive terminal. Whether the negative and / or positive terminal is temporal is dependent on the applied current, such as AC or DC. For instance, if a direct current (DC) is applied, the negative and / or positive terminal are generally constantly the negative and / or positive terminal but could alternate based on source settings. In some cases, the direct current may be applied across the electrodes of the electrochemical cell, with the direction of the current switching at controlled intervals. Reversing directions may benefit the electrochemical cell, as all electrodes may dissolve equally which may prevent localized dissolution (hole forming). This method lowers the leftover material after operation and prevents voltage spikes, with the latter being related to increased current density at reduced surface area. Alternating directions may reduce material build-up on the electrode’s surface and reduce sludge layers on the electrode over time. On the other hand, for an alternative current (AC) the negative and / or positive terminal may periodically alternate. A set of electrodes may be inter-connected in a serial or parallel configuration, and / or a combination of both. Alternatively, or additionally, the system could be setup to allow for a bi-polar electrode to form. Thus, one side of the electrode functioning as anode (z.e. anodic side) and one side functioning as cathode (z.e. cathodic side). As is known to a person skilled in the art, the exact function of the electrodes may depend on the manner the current is applied and on the exact configuration of the electrochemical cell. At least one of such electrodes is typically sacrificial.

[0044] Water flows

[0045] Feed water may be sources from a relevant step of a water treatment system. For example, at a stage in the water treatment system where a water fluid stream comprises non-soluble particles and other impurities, the water fluid stream of the water treatment system may be provided to (e.g., fluidically coupled with) the product stream from the electrochemical cell. The water fluid stream from the water treatment system (e.g., the water treatment stream) may not pass through theWSGR Docket No. 71441-701.601 electrochemical cell. For example, the fluid of the electrochemical cell may be upstream of a point where the product stream comprising the water treatment agent is provided to the water treatment stream. A separate water source stream may be provided to the electrochemical cell. The separate water source stream may be provided from a separate part of the water treatment system. The water source stream may be lower in impurities than the water treatment stream. This may reduce fouling on the electrodes in the electrochemical cell. Where the water source stream to the production of the water treatment agent has a different composition that the water treatment stream where the water treatment agent is provided, this may improve the efficiency of producing the water treatment agent and the efficiency of treating the water treatment stream. This may also provide for additional control of the composition and dosing of the water treatment agent, as discussed further herein. The electrolyte fluid (23), i.e. the fluid in the electrochemical cell, may comprise feed water. The electrolyte provides the medium wherein the water treatment agent (2) is generated, resulting in a product stream (8), being fluidically connected to said water treatment stream.

[0046] The term ‘feed water’ may be a fraction from an influent water stream of said water treatment system (3), and / or a fraction from an effluent water stream of said water treatment system (6). Alternatively, it may originate from another-sourced water stream (5)

[0047] The influent stream may be any suitable water stream. The influent stream is typically a water stream that has some contaminants and / or impurities. The influent stream typically still requires one or more treatment steps before it is suitable for its determined purpose. It may however be appreciated that the influent stream may have been subjected to one or more water treatment steps but is typically not yet fully purified. Such water treatment steps may be one or more of sedimentation, precipitation, flotation, membrane filtration, sludge conditioning systems, odor control systems and / or others.

[0048] The effluent stream is typically considered the stream that is the output of the one or more water treatment steps to which the intermediate water stream may be subjected. Accordingly, the effluent stream is typically treated water stream that exits a treatment step or treatment plant. The effluent water stream is accordingly preferably downstream of the water treatment step. Thus, the effluent stream is generally considered a ‘cleaner’, i.e. subjected to more water treatment steps, than the influent stream and intermediate stream.

[0049] The term ‘other-sourced water’ is typically used in the art to describe water originating from various sources, that are not particularly specified. For instance, this could be drinking water, ground water, surface water, municipal wastewater and / or industrial process water such as water from and / or within the petrochemical, paper, dairy, food and beverage industry.WSGR Docket No. 71441-701.601

[0050] The feed water (e.g., the fluid stream provided to the electrochemical cell) may accordingly be a fraction of the influent water stream and / or effluent water stream of the water treatment system. It was found that particular good results were obtained, and this is thus particularly preferred, if the feed water is 0.005 to 10 vol%, preferably 0.01 to 5 vol%, more preferably 0.05 to 1 vol% of the influent water stream and / or effluent water stream, based on the total volume of the influent water stream and / or effluent water stream. In some cases, the feed water stream (e.g., water source to electrochemical cell) comprises a total fluid flow that is about 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 vol% of the influent or effluent water stream of the water treatment system. In some cases, the feed water stream total fluid flow is greater than or equal to a value listed above, for example greater than or equal to about 0.05 vol %. The feed water stream total fluid flow may be less than or equal to a value listed above, for example less than or equal to 1% of the effluent or influent water stream of the water treatment system. The feed water stream total fluid flow may be between any two values described above, for example between about 0.05 and 1% of the influent or effluent water stream of the water treatment system. Due to the presence of less impurities of the effluent stream, it is generally advantageous for the feed water to be a fraction of the effluent water stream. This generally results in less passivation, known as fouling, of the electrode and / or unwanted interference of species within the electrolyte matrix. Beneficially, this allows for a higher efficiency of the electrolysis process, resulting in lower energy consumption. Additionally, the electrodes typically require less frequent cleaning, reducing both maintenance time and costs.

[0051] Advantageously, using only a fraction of the influent and / or effluent water streams, the method allows for more accurate dosing. Additionally, it allows for a compact system, an improved control over the feed water and thus for less passivation and less bio-fouling. By directing a fraction of the total fluid transfer through the water treatment system through the electrochemical cell, an optimal fluid flow to produce the water treatment agent can be controlled separately from the total fluid flow through the water treatment system.

[0052] Similarly, using other sourced water stream typically allows for controllability and reduced passivation of the electrodes.

[0053] Upon introduction of the treatment agent into the influent stream, an intermediate stream is formed. The intermediate stream is typically further led to or provided to a further water treatment step. Accordingly, the method preferably further comprises leading the intermediate stream to a water treatment step. The intermediate stream may comprise at least a partial mix of the product stream and the water treatment fluid stream.WSGR Docket No. 71441-701.601

[0054] The water treatment system or water treatment stream may be the water stream comprising the impurities that the water treatment agent is provided to. The water treatment stream may have a total fluid flow greater than or equal to about 0.1, 0.5, 1, 3, 5, 7, 10, 15, 20, 50, 100, 150, 200, 300, 500, 750, 1000 or greater liters per minute. The water treatment system may be a municipal water treatment system. The water treatment system may be a continuous or batch system.

[0055] The total dissolved organic carbon (DOC) levels of the water treatment stream may be greater than or equal to about 0.5, 0.8, 1, 1.3, 1.5, 1.8, 2.0, 2.3, 2.5, 2.8, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 mg C / L, or greater. Treatment with the water treatment agent may reduce the total dissolved organic carbon concentration by at least about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.3, 1.5, 1.8, 2.0, 2.3, 2.5, 2.8, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0 mg C / L, or greater. A concentration of phosphate species in the water treatment stream, prior to treatment, may be greater than or equal to about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.3, 1.5, 1.8, 2.0, 2.3, 2.5, 2.8, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, mg P / L or greater. The concentration of phosphate species may be reduced by the water treatment agent by 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.3, 1.5, 1.8, 2.0, 2.3, 2.5, 2.8, 3.0, 3.5, 4.0, 4.5, 5.0, 6.0, 7.0, 8.0, 9.0, 10.0, mg P / L or greater.

[0056] An explementary method is schematically illustrated in Figure 1. As illustrated herein, an electrochemical cell 2 may be employed, comprising at least one sacrificial electrode 21, at least one counter electrode 22, and an electrolyte 23. The electrolyte comprises feed water, that may originate from other sourced water stream 5, a fraction of influent water stream 3 and / or a fraction of effluent water stream 6. The treatment agent 1 typically leaves the electrochemical cell 2 in a product stream 8, that comprises the treatment agent and an electrolyte bleed stream. The product stream may be introduced into the influent stream, obtaining intermediate stream 4, that may be subjected to a water treatment step 7.

[0057] Conductivity enhancing - Salt dosing

[0058] As may be appreciated, it is typically preferred that the electrolyte has a sufficient conductivity. Not only does this allow for efficient generation of the treatment agent, but it may also advantageously allow for less passivation of the electrodes. Accordingly, the electrolyte typically has a conductivity of at least 1000 pS / cm, preferably at least 2000 pS / cm, more preferably at least 4000 pS / cm. Even better results were obtained for the more preferred case wherein the electrolyte has a conductivity of at least 5000 pS / cm, such as at least 5500 pS / cm. The conductivity is typically measured at a temperature of 20 °C. It may be appreciated that the temperature of the electrolyte during use may be lower or higher. The conductivity may be measured in accordance with ISO7888:1985.WSGR Docket No. 71441-701.601

[0059] In some cases, the conductivity of the feed water may be insufficient to have an electrolyte with the preferred conductivity. Accordingly, the conductivity may be increased. The method thus preferably further comprises increasing the conductivity of the electrolyte and accordingly lower the resistance. This may be achieved by a variety of means. Several particularly suitable methods include the introduction of conductivity enhancers, such as the introduction of ions (such as by adding salts such as sodium, potassium, chloride and / or sulfate salts) and / or introduction of conductivity polymers. Specifically the use of chloride (C1-) based salts is considered over the use of anions like sulfate and nitrate, with the latter resulting in significant passivation and thus reduced electrochemical efficiency. This electrochemical efficiency, known as Faradaic Efficiency (FE), is the ratio of the actual amount of chemical product generated in solution to the theoretical amount expected based on the total electric charge passed, indicating how efficiently electrons contribute to the desired electrochemical reaction. By producing the water treatment agent (the Fe-product) external to the main flow of the water treatment system, the chloride-load to the water in the water treatment system is not significant, minimizing consequences for human health and the environment. Other methods may include pH adjustment, plasma treatment and / or increasing the temperature of the feed water. By lowering or increasing the pH, deviating from neutral pH (pH 7), the presence of ions, as H+ and OH-, may be increased, contributing to the conductivity of the electrolyte in the electrochemical cell. Preferably lowering the pH, may promote the presence of (partial) soluble compounds, as Fe(OH)+ (see onwards), additionally increasing conductivity of the electrolyte. Additionally, adjusting the pH may increase the Faradaic efficiency of the production reaction of the water treatment agent. This may be achieved in line or in a conductivity enhancer.

[0060] Figure 2 schematically illustrates an embodiment wherein the conductivity is enhanced in a conductivity enhancer 17 before entry into the electrochemical cell. Using a conductivity enhancer may be advantageous as this typically allows for better mixing of the conductivity enhancers with the feed water, providing stable conductivity conditions in the electrochemical cell. For efficiency purposes, it is typically better to enhance the conductivity of the electrolyte by treating the feed water before it enters the electrochemical cell.

[0061] Energy consumption

[0062] The current that is applied onto the electrode may depend on a variety of factors. For instance, it may depend on the material of the electrodes, but also on the characteristics of the influent water stream, electrochemical settings, and / or the configuration of the electrodes. It is typically preferred that the current is in the range of 0.5 to 15 kAV / kg metal, preferably in the range of 1 to 12 kAV / kg metal. The current may also be dependent on the material of theWSGR Docket No. 71441-701.601 electrodes. If the electrodes comprise iron, it may be preferred to apply a current in the range of 0.5 to 5 kAV / kg iron, preferably 0.8 to 3 kAV / kg iron. While for electrodes comprising aluminum, it may be preferred to apply a current in the range of 1 to 15 kAV / kg aluminum, preferably in the range of 1 to 10 kAV / kg aluminum. The voltage allows for a low safety risk.

[0063] Iron chemistry - product

[0064] Due to the applied current, oxidation occurs at the anode (or anodic side) and reduction at the cathode (or cathodic side, i.e. counter-electrode (inert) side). Due to the material of the electrode, the treatment agent typically comprises a metal, preferably iron. Accordingly, the treatment agent is typically a metal-based treatment agent. Typically, at the cathode a Hydrogen Evolution Reaction (HER) according to (I) occurs (in an Alkaline electrolyte), while at the anode a reaction according to (II) occurs. Nonetheless, it may be appreciated that other reactions may occur, such as the acidic form of the HER or other side reactions, such as the reduction of other species.

[0067] In formula (II), M is a metal and n is an integer of 1 or more.

[0068] Accordingly, it may be appreciated that the anode (or anodic side) may be considered the sacrificial electrode.

[0069] Due to these reactions typically taking place, the treatment agent may be generated. Often, in case of iron, the treatment agent may comprise an iron-oxy-hydroxide and / or an iron-oxide and / or an iron-hydroxide formed from the reaction products of (I), (II) and / or with any reagents present in the electrolyte. Typically, the treatment agent is characterized as; Mx0y(0H)z, wherein M represents Fe, x is larger than 0, y is 0 or more and z 0 or more, where y + z is larger than 0, preferably wherein M is Fe2+ (Fell) and / or Fe3+ (Felll). Results for various applications have shown that in the production of the water treatment agent it is not necessary to achieve full ‘ionization’ to free Fe2+ / Fe3+; where usually (as FeC13): M represents Fe, x is larger than 0, y is 0 and z is 0, and x + y = 0. In contrast to conventional alternatives, this method produces the iron coagulant in a flock-form (solid as for example; Fe(OH)2, Fe(OH)3, Magnetite, Green Rust) or in a Pre-Hydrolyzed Iron (PHI) form (as for example FeIII(OH)2+). Beneficially, disadvantages of other proposed solutions, where fully-ionized metal salts are produced, are overcome, with Fe2+ known to cause electroplating, i.e. deposition, on the cathode. Additionally, the presence of aforementioned flock and pre-hydrolyzed forms allows for in-situ oxidation with oxygen over expensive and polluting other strong oxidants as C12, which would thermodynamically not be possible in strong acidic conditions (pH < 4) when considering fully-ionized iron ions. Besides, theWSGR Docket No. 71441-701.601 shift from strongly-acidic conditions to mildly-acidic conditions, significantly lowers safety hazards, promoting a safer working environment.

[0070] . In some cases, the water treatment agent comprises magnetite (FesCU), green rust, Fe(OH)3, Fe(OH)2 geothite and / or lepidocrocite. Green rust is a term well known in the art to describe crystalline compounds comprising iron (II), iron (III) cations, hydroxide (OFF) ions and other anion such as carbonate (CO32), chloride (CF), bromide (Br ), fluoride (F‘), iodide (F), nitrate (NO3 ), selenate (SeOF) and / or sulfate (SC2-). Accordingly, some examples of green rust include carbonate green rust ([Fe42+Fe23+(HO')i2]2+• [CCE2-• 2H2O]2), chloride green rust ([Fe32+Fe3+(HO’ )is]+• [CF • n hO] ) and sulfate green rust ([Fe42+Fe23+(HO’)i2]2+• [SO42’ • 2H2O]2). After the product leaves the electrochemical cell, it may undergo additional processing. The method may accordingly further comprise processing the treatment agent. This processing step may include aeration and / or oxygen injection to further refine the treatment agent, for instance to achieve the desired molecular composition, as oxidation of Fell to Felll. This is particularly preferred in case green rust is formed, to oxidize the green rust (Fell-Felll mixture) to iron hydroxide. The processing step may also include the introduction of a processing stream for further pH adjustment, consisting out of an acid or base. Addition of a processing stream can be used to enhance the reactivity of the water treatment agent. At near-neutral pH conditions in the electrochemical cell, when limited pH control is applied, the produced water treatment agent has limited reactivity for removal of phosphate and organic material in the water treatment system. Enhancing this reactivity would thus be desired for specific removal purposes. This processing may be performed at any stage after the electrochemical cell, for instance in and / or after a separator and / or a dosing chamber, preferably in the agitation unit (vide infra). However, it may be appreciated that the processing is performed before introducing the treatment agent, into the influent stream.The impurities that are generally found in water streams include arsenic, chromium, lead, sulfide, phosphates, fluoride, suspended particles, pathogens (as bacteria and viruses), and / or organic material. The treatment agent may advantageously be employed as a coagulant (precipitant), subsequent flocculant, and / or an ad- and / or absorbent as an alternative to metal salts to aid in the removal of such impurities. The treatment agent is introduced into the influent stream. The water treatment agent showed similar performance as fully-ionized products, like conventional metal salts as FeC13 and FeC12.5. Experiments were performed for phosphate and organic matter removal, and sludge dewaterability (increased dry-solid content). Additionally, these results showed the potential for reduced chloride introduction.WSGR Docket No. 71441-701.601

[0071] Internal product flows (within - around the electrochemical cell)

[0072] As schematically illustrated in Figure 3, the treatment agent 1 typically leaves the electrochemical cell (2) in a product stream (8), that comprises the treatment agent and an electrolyte bleed stream. The product stream is typically a mixture of electrolyte (liquid) and dissolved and / or particulate form of the treatment agent and can generally be considered a slurry. This electrolyte bleed stream is thus typically at least part of the electrolyte 23 that was present in the electrochemical cell. This product stream may be led to a separator 12, to at least partially separate the treatment agent from the electrolyte bleed stream. This generally results in a more concentrated product stream, i.e. a higher concentration of treatment agent. The separator may be any suitable separator, such as filtration, flotation, and / or sedimentation. Preferably, flotation is used due to the floating tendencies of the formed treatment agent, typically due to the presence of hydrogen gas in the electrochemical cell (vide infra). To increase the floating capacity, air and / or any other suitable gas can be introduced into the separator, for example, as white water. This allows for the treatment agent to better float on the electrolyte bleed stream. This may advantageously also be at least part of the optional processing step. The treatment agent may be at least partially separated by e.g. scooping it from the electrolyte bleed stream. This is preferably performed before introducing the product stream and accordingly the treatment agent into the influent water stream 3. At least part of the electrolyte bleed stream may suitably be recycled and the method may thus further comprise leading at least part (such as a first fraction) of the electrolyte bleed stream 222 to the electrochemical cell 2. Alternatively, the separator acts as a collector where part of the electrolyte with water treatment agent is abstracted from the electrochemical cell, i.e. separated from the electrochemical cell. A fraction of the product stream can be dosed to the water treatment step, while the remaining fraction is recycled. Recirculation may allow for turbulence and mixing in the electrochemical cell, which would not be possible in a single-pass system. This may promote the transport of the produced water treatment agent from the sacrificial anode, enhancing electrochemical efficiency. Additionally, the recirculation may promote mixing of pH gradients near the electrochemical cell.

[0073] Depending on the conditions, it may be that the treatment agent originating from the electrochemical cell and / or separator is too concentrated to add to the influent stream. In order to ease dosing, the method may further comprise leading the product stream to a dosing chamber. In case a separator is employed, this dosing chamber is typically situated downstream of the separator.

[0074] As schematically illustrated in Figure 4, to dilute the product stream and accordingly the treatment agent 1, a processing water stream (herein also referred to as processing stream) may be led to the dosing chamber 13. The processing water stream may be a fraction of the influent waterWSGR Docket No. 71441-701.601 stream 3, a fraction of the intermediate water stream 4, a fraction of effluent water stream 6 and / or other sourced water stream 5. It may be appreciated that the other sourced water may be individually and independent from the other sourced water 5 introduced in the electrochemical cell. The dosing chamber 13 advantageously also allows for a temporary storage of the treatment agent 1, such that the dosing into the influent water stream 3 may be accurately controlled. Figure 4 illustrates the dosing chamber downstream from the separator. It may however be appreciated, that the dosing chamber may independently be employed from the separator. Accordingly, the product stream leaving the electrochemical cell may also directly be led to the dosing chamber.

[0075] The dosing chamber may comprise an agitation unit, such as a mixer. This allows for the treatment agent to at least partially, or completely, dissolve (and / or uniformly mixed - nonconglomerated) such that dosing to the influent stream is easier.

[0076] Particularly suitable concentrations of the treatment agent in the product stream may be obtained when the method comprising adding the processing water stream to the dosing chamber in a ratio of treatment agent to processing water stream of less than 1 : 10, preferably less than 1 :50, more preferably less than 1 :75, such as 1 : 100.

[0077] It is most preferred that the product stream that is introduced into the influent stream has a concentration of at least 250 mg metal of the treatment agent per liter product stream, preferably at least 500 mg / 1, more preferably at least 1000 mg / 1. Accordingly, the concentration of the treatment agent typically depends on the exact composition of the treatment agent.

[0078] Due to the introduction of the treatment agent into the influent stream, impurities from the influent stream may coagulate, react, and / or interact with the treatment agent. Accordingly, in the intermediate stream, aggregates of the impurities are typically present. Upon leading the intermediate stream into a preferred further water treatment step, these aggregates may be removed. Accordingly, the introduction of the treatment agent aids in the purification of water streams.Hydrogen gas as valuable by-product

[0079] The reactions at the cathode typically provide hydrogen gas. Thus, the application of the current generally allows for the generation of hydrogen gas. The formation of hydrogen gas advantageously results in a turbulence in the electrochemical cell, that allows to clean the electrodes resulting in less passivation. As may be appreciated, it may occur that some of the formed hydrogen gas is enclosed and / or encapsulated in the treatment agent. The hydrogen gas enclosed and / or encapsulated by the treatment agent is typically at least partially liberated by the optional separation. As schematically illustrated in Figure 5, hydrogen gas 14 may originate from the electrochemical cell 2, due to the reaction occurring at the cathode. Hydrogen gas 14 mayWSGR Docket No. 71441-701.601 alternatively or additionally be liberated by separation in the separator 12 and / or in the dosing chamber. To utilize the energy from the hydrogen gas, the method preferably advantageously comprises leading the hydrogen gas 14 to a fuel cell 15. This fuel cell allows to generate electricity 16 from the hydrogen gas, which may advantageously be employed for applying the current. Accordingly, beneficially the hydrogen gas may be employed to at least partially power the electrochemical cell 2. It may be appreciated that the fuel cell is not particularly limited, and a skilled person is aware of suitable systems. Additionally, or alternatively, the hydrogen gas may be stored in a hydrogen storage tank (not illustrated). This allows for the hydrogen gas to be utilized for other processes.

[0080] A particularly preferred method is schematically illustrated in Figure 6. Here, it is illustrated that the conductivity is enhanced in a conductivity enhancer 17 before entry into the electrochemical cell. In addition, the formed hydrogen gas 14 is illustrated to be led to a fuel cell 15 to generate electricity 16, that may be used to fuel the electrochemical cell 2. Figure 6 further illustrates the preference to lead the product stream 8 to a separator 12 and further to a dosing chamber 13 before introduction into the influent stream 3.

[0081] The present invention further pertains to an electrochemical cell for use in the method. The electrochemical cell accordingly comprises a sacrificial electrode. A further aspect relates to a water treatment agent produced by the method. A further aspect relates to a water treatment system for the method. This system comprises the electrochemical cell.EXAMPLES

[0082] Experimental Procedures

[0083] A fixed process condition was selected for the method for producing the water treatment agent; pH and salt-matrix were fixed, and the formed water treatment agent was tested for Fe content using HACH cuvette-kits (LCK 321). The water treatment agent was conditioned to enable phosphate and organics (DOC) removal and allow for dewatering in sludge treatment. Chloride in the product is a consequence of conductivity enhancement (NaCl and pH control) and reactivity enhancement using an external acid stream.

[0084] For the removal experiments, the water treatment agent, from now; “CIWI-Fe”, or FeCh was dosed to the beaker containing water from the selected water treatment plant to achieve desired Fe dose (mg Fe / L). The general procedure was according to a standard procedure: Flocks were dosed during rapid mixing (200 RPM), followed by medium intensity mixing at 50 RPM for 2 minutes and slow mixing at 10 RPM for 15 minutes. After 15-30 minutes of settling, phosphate and / or dissolved organic carbon (DOC) samples of supernatant (SN) clear water were taken.WSGR Docket No. 71441-701.601

[0085] For the sludge treatment experiments, CIWI-Fe or FeCh was dosed, together with a fixed amount of polymer (PE), to a shaking device containing sludge from a wastewater treatment plant (WWTP). The shaking device was used to mix the coagulant and PE with the sludge, subsequently a centrifuge was used to dewater the sludge. An oven was used to determine the dry solid (ds) content of the treated sludge.

[0086] Example 1 - Phosphate Removal with Water Treatment Agent (CIWI-Fe) WWTP 1

[0087] Influent water of WWTP 1, collected after pre-settling, was collected on the 17thof January 2025. The phosphate influent concentration was 11.2 mg P / L. The effectiveness of the CIWI-Fe product for the removal of phosphate was investigated. Results showed that similar P-removal (mg PO4-P / L removed) could be achieved by CIWI-Fe dosing for a product with a Cl / Fe-ratio of 2.0: 1. Lower Cl / Fe-ratio’ s resulted in decreased P-removal. The results are shown in Figure 7.

[0088] Example 2 - Phosphate Removal with Water Treatment Agent (CIWI-Fe) WWTP 2

[0089] Influent water of WWTP 2, as direct influent, was collected on the 19thof February 2025. The phosphate influent concentration was 4.23 mg P / L. The effectiveness of the CIWI-Fe product for the removal of phosphate was investigated. Results showed that similar P-removal (mg PO4-P / L removed) could be achieved by CIWI-Fe dosing for a product with a Cl / Fe-ratio of 1.4: 1. Lower Cl / Fe-ratios resulted in decreased P-removal. The results are shown in Figure 8.

[0090] Example 3 - Phosphate Removal with Water Treatment Agent (CIWI-Fe) WWTP 3

[0091] Influent water of WWTP 3, as direct influent, was collected on the 18th of February 2025. The phosphate influent concentration was 2.31 mg P / L. The effectiveness of the CIWI-Fe product for the removal of phosphate was investigated. Results showed that similar P-removal (mg PO4- P / L removed) could be achieved by CIWI-Fe dosing for a product with a Cl / Fe-ratio of 1.6: 1. Lower Cl / Fe-ratios resulted in decreased P-removal. Phosphate concentrations as low as 0.1 mg P / L were observed, showing direct potential for application of the technology in low-range phosphate environments. The results are shown in Figure 9.

[0092] Example 4 - Phosphate Removal with Water Treatment Agent (CIWI-Fe) WWTP 4

[0093] Influent water of WWTP 4, post-sieve, was collected on the 3rd of March 2025. The phosphate influent concentration was 5.8 mg P / L. The effectiveness of the CIWI-Fe product for the removal of phosphate was investigated. Results showed that similar P-removal to FeC13 (mg PO4- P / L removed) could be achieved by CIWI-Fe dosing for a product with a Cl / Fe-ratio of 1.6: 1. Lower Cl / Fe-ratios resulted in slightly lower P-removal. The results are shown in Figure 10.

[0094] For the purpose of clarity and conciseness, description features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.WSGR Docket No. 71441-701.601

[0095] While preferred embodiments of the present disclosure have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. It is not intended that the present disclosure be limited by the specific examples provided within the specification. While the present disclosure has been described with reference to the aforementioned specification, the descriptions and illustrations of the embodiments herein are not meant to be construed in a limiting sense. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the scope of the present disclosure. Furthermore, it shall be understood that all aspects of the present disclosure are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. It should be understood that various alternatives to the embodiments of the present disclosure described herein may be employed in practicing the embodiments of the present disclosure. It is therefore contemplated that the present disclosure shall also cover any such alternatives, modifications, variations, or equivalents. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby.

[0096] Whenever the term “at least,” “greater than,” or “greater than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “at least,” “greater than” or “greater than or equal to” applies to each of the numerical values in that series of numerical values. For example, greater than or equal to 1, 2, or 3 is equivalent to greater than or equal to 1, greater than or equal to 2, or greater than or equal to 3.

[0097] Whenever the term “no more than,” “less than,” or “less than or equal to” precedes the first numerical value in a series of two or more numerical values, the term “no more than,” “less than,” or “less than or equal to” applies to each of the numerical values in that series of numerical values. For example, less than or equal to 3, 2, or 1 is equivalent to less than or equal to 3, less than or equal to 2, or less than or equal to 1.

[0098] Certain inventive embodiments herein contemplate numerical ranges. When ranges are present, the ranges include the range endpoints. Additionally, every sub range and value within the range is present as if explicitly written out. The term “about” or “approximately” may mean within an acceptable error range for the particular value, which will depend in part on how the value is measured or determined, e.g., the limitations of the measurement system. For example, “about” may mean within 1 or more than 1 standard deviation, per the practice in the art. Alternatively, “about” may mean a range of up to 20%, up to 10%, up to 5%, or up to 1% of a given value. Where particular values are described in the application and claims, unless otherwise stated the term “about” meaning within an acceptable error range for the particular value may be assumed.

Claims

WSGR Docket No. 71441-701.601CLAIMSWHAT IS CLAIMED IS:

1. A method for producing a water treatment agent in parallel to a water treatment system, said method comprising:(a) providing an electrochemical cell comprising at least one sacrificial electrode, at least one counter electrode, and an electrolyte fluid comprising feed water, wherein said sacrificial electrode comprises iron;(b) applying a current between said at least one sacrificial electrode and said at least one counter electrode to form said water treatment agent in a product stream, wherein said product stream is fluidically connected to said water treatment system, and wherein said water treatment agent comprises MxOy(OH)z, wherein M represents a metal, x is larger than 0, and (i) y is greater than zero and / or z is greater than zero.2 The method of claim 1, wherein the water treatment agent comprises iron.3 The method of claim 1, wherein the chemical formula of the water treatment agent comprises M representing iron (Fe).4 The method of claim 1, wherein said feed water is a fraction from an influent water stream of said water treatment system, and / or a fraction from an effluent water stream of said water treatment system.5 The method of claim 4, wherein said feed water is from a sourced water stream external to said water treatment system.6 The method of claim 1, wherein said treatment agent has a concentration in said product stream of at least about 250 mg / L.7 The method of claim 1, wherein said treatment agent has a concentration in said product stream of at least about 500 mg / L.8 The method of claim 1, wherein said treatment agent has a concentration in said product stream of at least about 1000 mg / L.9 The method of claim 2, wherein said feed water comprises about 0.005% to about 10% of said influent water stream or said effluent water stream of said water treatment system.10 The method of claim 2, wherein a total fluid flow through said electrochemical cell comprises between about 0.05 vol% to about 5 vol% of a total flow of an effluent stream of said water treatment system.11 The method of claim 2, wherein said treatment agent comprises a ratio of chloride to iron of less than 3: 1.WSGR Docket No. 71441-701.60112. The method of claim 1, wherein said treatment agent comprises a ratio of inorganic anions from one or more strong acids to metal valence state of less than 1 : 1.

13. The method of claim 12, wherein said metal is iron, and said treatment agent comprises a ratio of inorganic anions from one or more strong acids to iron valence state of less than 1 : 1.

14. The method of claim 12 or 13, wherein said inorganic anions from one or more strong acids comprise chloride ions.

15. The method of claim 12 or 13, wherein said inorganic anions from one or more strong acids comprise sulfate ions.

16. The method of claim 12 or 13, wherein said inorganic anions form one or more strong acids comprise chloride ions and sulfate ions.

17. The method of claim 16, wherein said chloride ions and said sulfate ions are in a ratio between 4: 1 and 1 :4.

18. The method of claim 2, wherein said product stream comprising said treatment agent has at least a 10% reduction of chloride ions than an equivalent iron dosage from iron chloride salts, or a solution thereof.

19. The method of claim 1, further comprising directing said intermediate water stream to a water treatment step.

20. The method of claim 1, wherein said feed water comprises 0.005 to 10 vol% of the effluent water stream, based on the total volume of the effluent water stream.

21. The method of claim 1, wherein said feed water comprises 0.05 to 5 vol% of the effluent water stream, based on the total volume of the effluent water stream.

22. The method of claim 1, wherein said feed water comprises 0.01 to 1 vol% of the effluent water stream, based on the total volume of the effluent water stream.

23. The method of any one of claims 1-22, wherein said electrolyte has a conductivity of at least 1000 pS / cm.

24. The method of any one of claims 1-22, wherein said electrolyte has a conductivity of at least 1500 pS / cm.

25. The method of any one of claims 1-22, wherein said electrolyte has a conductivity of at least 2000 pS / cm.

26. The method of any one of claims 1-25, further comprising increasing the conductivity of the electrolyte by one or more of (i) introduction of one or more conductivity enhancers in the feed water, (ii) by plasma treatment, (iii) by pH adjustment and (iv) increasing a temperature of the feed water.WSGR Docket No. 71441-701.60127. The method of claim 26, wherein a conductivity enhancer of said one or more conductivity enhancers is chloride-based.

28. The method of claim 27, wherein said chloride-based conductivity enhancer comprises sodium chloride or potassium chloride.

29. The method of claim 26, wherein said pH adjustment comprises providing hydrochloric acid.

30. The method of any one of claims 1-29, further comprising leading said product stream to a separator to at least partially separate said water treatment agent from said electrolyte fluid.

31. The method of claim 1, further comprising mixing said product steam with a water fluid stream of said water treatment system.

32. The method of claim 30, wherein said electrolyte fluid is at least partially separated from said water treatment agent prior to said providing said treatment agent to said water treatment system.

33. The method of any one of claims 1-30, further comprising recycling at least part of said electrolyte fluid into said electrochemical cell.

34. The method of claim 30, further comprising leading said product stream and a processing water stream into a dosing chamber, wherein said processing water stream is a fraction of said influent water stream, said effluent water stream, and / or other sourced water stream, and wherein said dosing chamber is downstream from said separator.

35. The method of any one of claims 32-34, wherein said water stream has a pH of less than 7.

36. The method of any one or claims 32-35, wherein said water stream comprises hydrochloric acid.

37. The method of any one of claims 1-36, further comprising processing said water treatment agent before introducing said product stream into said influent water stream, wherein said processing comprises aeration and / or oxygen injection.

38. The method of any one of claims 1-37, further comprising generating or collecting hydrogen gas from said electrochemical cell and leading said hydrogen gas to a fuel cell to generate electricity.

39. The method of claim 38, wherein said electricity is employed for applying said current in said electrochemical cell.

40. The method of any one of claims 1-39, wherein said current is in the range of 0.5 to 15 kAV / kg metal.WSGR Docket No. 71441-701.60141. The method of any one of claims 1-39, wherein said current is in the range of 1 to 12 kAV / kg metal.

42. A water treatment system comprising an electrochemical cell configured to produce a water treatment agent, wherein said electrochemical cell comprises at least one sacrificial electrode, at least one counter electrode, and an electrolyte fluid comprising water, wherein said sacrificial electrode comprises iron, wherein said electrochemical cell is fluidically connected to a water treatment stream of said water treatment system, and wherein a product stream from said electrochemical cell comprises said water treatment agent with the chemical formula MxOy(OH)z, wherein M represents a metal, x is larger than 0, and (i) y is greater than zero or z is greater than zero.

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