WO2012177366A2

WO2012177366A2 - Methods for cleaning water filtration media

Info

Publication number: WO2012177366A2
Application number: PCT/US2012/040010
Authority: WO
Inventors: Stephen D. O'connor; C.J. Yu
Original assignee: Blue Earth Labs, Llc
Priority date: 2011-06-23
Filing date: 2012-05-30
Publication date: 2012-12-27
Also published as: WO2012177366A3

Abstract

A method of removing contaminants from water filtration media is disclosed, including (a) applying a granular cleaner to the water filtration media, and (b) after step (a), applying multiple discrete doses of an activator to the water filtration media at predetermined time intervals. Further disclosed is a method of cleaning water filtration media, including (a) applying a granular cleaner to the water filtration media that is reactive with at least one first inorganic contaminant; (b) after step (a), applying a liquid cleaner to the water filtration media that is compositionally different from the granular cleaner and reactive with at least one second inorganic contaminant; and (c) after step (b), applying an activator to the water filtration media that is reactive with an organic contaminant. A method of cleaning water filtration media is also disclosed including agitating at least a portion of the water filtration media.

Description

METHODS FOR CLEANING WATER FILTRATION MEDIA

CROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims priority of U.S. Provisional Patent Application No. 61/500,607 filed on June 23, 201 1. The disclosure of the foregoing provisional patent application is hereby incorporated by reference herein in its entirety, for all purposes.

TECHNICAL FIELD

[0002] The present disclosure relates to methods for cleaning water filtration media.

BACKGROUND

[0003] In the field of water purification, a variety of filters or filter media types may be employed. Exemplary water filters or filtration media include, but are not limited to, media filters, screen filters, disk filters, slow sand filter beds, rapid sand filters, and cloth filters. Filtration media includes any media capable of filtering contaminants from water, wherein the media includes (but is not limited to) sand, granular carbon (including activated carbon or "GAC"), gravel, manganese, greensand, anthracite coal, and ion exchange media or ceramic beads. The goal of any water filtration system is to remove contaminants from water. Over time, the contaminants removed from the water build up in the filter, necessitating that the filter either be cleaned or discarded.

[0004] A heavy accumulation of contaminants can impede the flow of water and reduce filter performance. In particular, contaminant accumulation can result in increased filter backpressure, increased turbidity, and failure of the filter to adequately remove contaminants from the water being treated. Such contaminants commonly include organic matter, inorganic matter, or a combination thereof depending upon the water source. Large scale filtration can multiply the accumulation of contaminants, wherein such systems generally comprise various types of coal (e.g., anthracite), sand, GAC, or combinations thereof.

[0005] In most cases, the costs and down-time associated with replacing water filters far exceed the costs and down-time associated with cleaning such filters. Cleaning water filters, however, can be a complex and expensive process depending upon on the makeup of contaminants to be cleaned and the filter media necessitating cleaning. Difficulties arise in selecting an appropriate cleaning agent or combination of agents capable of removing (e.g., dissolving) the organic and/or inorganic matter, limiting the amount of residual agent(s) left behind in the filter media, and avoiding damage to the filter media. When deposits include multiple contaminants (e.g., metal oxides, carbonates, and biological films), a different agent may be required to remove each individual contaminant or contaminant type.

[0006] One known method for treating both organic and inorganic matter includes applying granular sulfamic acid to a filtration bed, followed by wetting the granular acid with water to at least partially dissolve the acid and cause the acid to penetrate into the filtration media, followed by application of an activator (e.g., oxygen donor) such as hydrogen peroxide. The sulfamic acid works to dissolve or otherwise remove at least certain types of inorganic matter, while the activator dissolves or otherwise removes at least certain types of organic matter. This method, however, has a number of limitations. For example, a large volume of granular acid and/or hydrogen peroxide is often required to adequately clean a filter. It may also be difficult to remove combinations of organic and inorganic matter that have become layered or encapsulated over time in or on the filtration media. High costs associated with transporting large amounts of granular acid and hydrogen peroxide provides an incentive to reduce the volume of such agents needed. In addition, sulfamic acid has limitations in dissolving certain inorganic substances, and current methods can require a considerable amount of time (in some cases, as much as 12 or more hours) before the application is applied, thereby extending downtime of the filtration media.

[0007] In consequence, the art continues to seek improved methods for cleaning water filtration media at lower cost, with increased efficacy, and with reduced filter downtime.

SUMMARY

[0008] The present disclosure relates to methods for cleaning water filtration media, and related cleaning compositions.

[0009] In one aspect, the disclosure relates to a method of removing contaminants from water filtration media, the method comprising: (a) applying a granular cleaner to the water filtration media; and (b) applying multiple discrete doses of an activator to the water filtration media at predetermined time intervals.

[0010] In another aspect, the disclosure relates to a method of cleaning water filtration media, the method comprising: (a) applying a granular cleaner to the water filtration media, wherein the granular cleaner is reactive with at least one inorganic contaminant; (b) after step (a), applying a liquid cleaner to the water filtration media, wherein the liquid cleaner is compositionally different from the granular cleaner and is reactive with at least one inorganic contaminant; and (c) after step (b), applying an activator to the water filtration media, wherein the activator is reactive with at least one organic contaminant.

[0011] In a further aspect, the disclosure relates to a method of cleaning water filtration media, the method comprising: (a) applying a first cleaner comprising granular sulfamic acid to the water filtration media; (b) after step (a), applying a second cleaner comprising formic acid to the water filtration media; and (c) after step (b), applying an activator to the water filtration media.

[0012] In a still further aspect, the disclosure relates to a method of cleaning water filtration media, the method comprising: (a) applying a granular cleaner to the water filtration media; (b) after step (a), applying a liquid cleaner to the water filtration media; (c) after step (b), applying an activator to the water filtration media; and (d) after any one or more of steps (a), (b), and (c), agitating at least a portion of the water filtration media.

[0013] Other aspects, features and embodiments of the disclosure will be more fully apparent from the ensuing disclosure and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG. 1 is a schematic flow chart disclosing steps of a method of cleaning filtration media including application of multiple discrete doses of an activator.

[0015] FIG. 2 is a schematic flow chart disclosing steps of a method of cleaning filtration media including use of a granular cleaner and a liquid cleaner that are compositionally different from one another.

[0016] FIG. 3 is a schematic flow chart disclosing steps of a method of cleaning filtration media including use of a first cleaner comprising granular sulfamic acid and a second cleaner comprising formic acid. [0017] FIG. 4 is a schematic flow chart disclosing steps of a method of cleaning filtration media including agitation of at least a portion of the filtration media.

[0018] FIG. 5 is a schematic flow chart disclosing steps of a method including sampling and analysis of filtration media, determination of agents suitable for cleaning the filtration media based on the analysis, and cleaning the filtration media employing agent(s) according to the determination.

DETAILED DESCRIPTION

[0019] The present disclosure relates to methods for cleaning water filtration media, and related cleaning compositions.

[0020] Unless otherwise defined, terms used herein should be construed to have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art. Further, the use of any term in this disclosure in one tense or context shall not be limited to only the tense or context of the term as used.

[0021] Unless the absence of one or more elements is specifically recited, the terms "comprising," "including," and "having" as used herein should be interpreted as open-ended terms that do not preclude the presence of one or more elements.

[0022] The term "contaminants" as used herein refers to any impurity, microorganism, disinfectant, disinfection byproduct, inorganic chemical, organic chemical, radionuclide, and other element, compound or organism harmful to mammals. Contaminants include those referenced by the U.S. Environmental Protection Agency as being "contaminants" as provided in the National Primary Drinking Water Regulations at http://water.epa.gov/drink/contaminants/upload/mcl- 2.pdf (as of June 3, 2011 ). Common types of contaminants include (but are not limited to) biofilms, metal oxides, and calcium carbonate scale. "Effective contaminant removal" as used herein refers to removal of sufficient quantity and/or quality of contaminants to meet any municipal, state, federal, and/or country guidelines, or predetermined filter performance criteria. In certain embodiments, effective contaminant removal may refer to restoration of filter media performance to within a desired cleaning efficacy and/or backpressure characteristic relative to new filter media of the same type, such as preferably within 90%, more preferably within 92.5%, more preferably within 95%, more preferably within 97%, and still more preferably within 99% of performance of new filter media of the same time. More modest cleaning efficacy is still envisioned by and encompassed within the scope of the present invention, however, since even modest cleaning (e.g., removing a relatively small percentage of contaminant material from a filter) may significantly improve filter performance.

[0023] The terms "cleaner" and "cleaning agent" generally refer agents that dissolve certain contaminants, preferably inorganic contaminants. In various embodiments, a cleaning agent includes an acid. Cleaning agents may be in granular and/or liquid form. In one embodiment, a cleaning agent includes any one or more of granular sulfamic acid and formic acid. Formic acid is preferably in liquid form. Desired concentrations for such cleaning agents include preferably at least about 0.5 pounds per cubic foot of filtration media, more preferably at least about 2 pounds per cubic foot of filtration media.

[0024] The term "activator" as used herein refers to compounds that dissolve certain contaminants, particularly organic contaminants (i.e., contaminants containing carbon). In certain embodiments, an activator comprises an activated oxygen donor (i.e., a compound that generates oxygen radicals in aqueous solution) including peroxides such as hydrogen peroxide, peracetic acid, precursors of peroxides, and combinations thereof. The term "activator" can also describe compounds that alter the chemical structure of various contaminants in the filter, such as by rendering contaminants soluble, by affecting polarity of contaminants, or by affecting one or other properties of contaminants to render contaminants more easily removed from filtration media than in the absence of the activator.

[0025] A method of removing contaminants from water filtration media according to at least one embodiment includes (a) applying a granular cleaner to the water filtration media, and (b) after step (a), applying multiple discrete doses of an activator to the water filtration media at predetermined time intervals.

[0026] A method according to at least one embodiment includes applying a granular sulfamic acid, followed by applying formic acid, thereafter followed by applying multiple discrete doses of hydrogen peroxide. Such method is particularly effective in removing layered and/or encapsulated inorganic and organic contaminants. Over time, filtration media can accumulate both inorganic and organic contaminants in various (e.g., alternating) layers or other encapsulated conformations within the filter media. Various individual cleaning agents approved for use with water filtration systems are typically capable of dissolving either inorganic contaminants or organic contaminants, but not both. Given the highly reactive nature of many activators (e.g., hydrogen peroxide), applying an activator in multiple discrete doses separated by time intervals may promotes increased efficacy in filter cleaning. For example, an initial application of one or more cleaners will dissolve at least some inorganic contaminants, particularly including inorganic contaminants that may coat or encase organic contaminants therein. After an initial (e.g., acid) cleaning step to expose underlying organic contaminants, an activator is applied to dissolve or otherwise remove at least some of the exposed organic contaminants. Additional organic contaminants, however, may either be (1 ) layered under additional layers of inorganic contaminants, or (2) not fully dissolved with the first dose of activator. Since activators may be highly reactive, such activators may be expended (e.g., neutralized) in a relatively short time (e.g. one to two hours). Once an initial dose of activator is expended (e.g., neutralized), conditions in a filtration bed housing the filtration media may remain acidic, suitable for dissolution or removal of inorganic contaminants. Additional (e.g., second, third, fourth, or higher numbered) discrete doses of activator may be sequentially applied after intervening periods of time (time intervals) to complete dissolution or removal of additional (e.g., underlying layers) of organic contaminants. As a result, multiple discrete doses of an activator according to one embodiment provides increased efficacy in removing of organic contaminants.

[0027] In various embodiments, a method of removing contaminants includes applying multiple discrete doses of an activator at predetermined time intervals. Such plurality of applications may include any number of applications (e.g., two, three, four, five, etc.). In one embodiment, at least three doses of activator are applied. The predetermined time interval(s) includes any time interval(s) suitable to allow the applied activator to dissolve or otherwise remove an effective amount of organic contaminants. In various embodiments, predetermined time intervals between application of discrete doses of activator include times of preferably at least about 15 minutes, at least about 30 minutes, at least about 45 minutes, at least about one hour, at least about 90 minutes, at least about two hours, at least about three hours, at least about four hours, and at least about eight hours. In one embodiment, at least one predetermined time interval between multiple discrete doses is at least about one hour. The number of doses of the length of predetermined time intervals may depend on the quantity and type of organic contaminants (which may be determined by analyzing core samples taken from the water filtration media prior to cleaning), the degree of encapsulation or layering of such contaminants with inorganic contaminants, and/or the concentration and amount of activator.

[0028] In one embodiment, one or more cleaning agents are applied first, followed by application of activator in three doses, wherein the three doses include a first dose of 40% of the total weight or volume of activator, a second application of 30% of the total weight or volume of the activator, and a third application of the remaining 30% of the total weight or volume of the activator.

[0029] In certain embodiments, the concentration and composition of the activator is the same for each discrete dose.

[0030] In other embodiments, the concentration and/or composition of the activator may change from dose to dose. Concentration may be ramped upward or downward from one dose to another dose, or concentration may increase or decrease in alternating fashion. In certain embodiments, an activator of a first concentration is applied in the first dose, followed by application of a second dose of activator having a second concentration lower than the first concentration, followed by application of a third dose of activator having a third concentration higher than the second concentration. Compositional changes of an activator from dose to dose may include presence or absence of additional oxygen donor species, presence or absence of surfactant(s), presence or absence of peracetic acid, presence or absence of other acid(s), presence or absence of coloring agent(s), and/or presence or absence of corrosion inhibitor (s).

[0031] In certain embodiments, an activator is applied to filtration media following application (and/or wetting) of one or more cleaning agent(s). In one embodiment, cleaning agents are applied to filtration media and given time to dissolve or otherwise interact with at least some inorganic contaminants, including inorganic material encasing or otherwise at least partially surrounding organic contaminants. Such time required for the cleaning agents to dissolve inorganic contaminants may vary in certain embodiments, and in preferred embodiments may range from one minute to twenty-four hours, more preferably from one hour to twenty-four hours, more preferably from two hours to twelve hours. In one embodiment, a predetermined time for cleaning agent(s) to dissolve inorganic contaminants includes the amount of time required to physically apply the activator to the filtration media. In a further embodiment, a predetermined time for cleaning agent(s) to dissolve inorganic contaminants depends upon the time required for the cleaning agent(s) to permeate (e.g., reach the bottom of) the filtration bed. The predetermined time for cleaning agent(s) to dissolve or otherwise interact with inorganic contaminants may be based on the number, type, and concentration of contaminants, degree of encapsulation of contaminants, and/or presence or absence of agitation of the filtration bed. Desirable times for cleaning agents to dissolve or otherwise interact with inorganic contaminants may be determined or otherwise predicted based on analysis of samples (e.g., core samples) of filtration media extracted prior to cleaning. One embodiment includes extracting at least one core sample from a filtration bed, analyzing the core sample, and determining amounts, composition, doses, and/or dose intervals for cleaning of the filtration bed based at least in part on the analysis, followed by cleaning of the filtration bed according to the determining step.

[0032] In various embodiments, a method of removing contaminants from water filtration media further includes taking at least one core sample from the water filtration bed and analyzing the core sample(s) to determine amount, composition, doses, and/or dose intervals for agents (e.g., granular and/or liquid cleaner(s) and activator(s)) for effective removal of contaminants from a filtration bed. Such sampling and analysis may include taking at least one representative core sample having a known volume from the filtration media, calculating the amount of cleaner(s) and/or activator(s) required for removal of contaminants from the filtration media in the sample(s), and extrapolating the result to the whole filtration bed (e.g., on a weight or volumetric basis).

[0033] In at least one embodiment, a method of cleaning water filtration media includes (a) applying a granular cleaner to the water filtration media, wherein the granular cleaner is reactive with at least one inorganic contaminant, (b), applying a liquid cleaner to the water filtration media after step (a), wherein the liquid cleaner is compositionally different from the granular cleaner and is reactive with at least one inorganic contaminant, and (c) applying an activator to the water filtration media after step (b), wherein the activator is reactive with an organic contaminant. In one embodiment, the granular cleaner and the liquid cleaner are reactive with different inorganic contaminants.

[0034] In various embodiments, application of a granular cleaner (e.g., sulfamic acid) dissolves certain inorganic contaminants differing from inorganic contaminants capable of being dissolved by a liquid cleaner (e.g., formic acid). Utilizing granular cleaner and liquid cleaner that are compositionally different enables dissolution or removal of a broader scope of inorganic contaminants than use of a single cleaner. In one embodiment, the dissolution of inorganic compounds is initiated before an activator is applied to dissolve the organic compounds, particularly when at least a portion of organic contaminants are encased by inorganic contaminants.

[0035] Additional advantages associated with use of a combination of a granular and liquid cleaner may include avoiding the need for a wetting step to dissolve the granular cleaner to promote (e.g., vertical) permeation of granular cleaner through the filtration media. Moreover, an increased activity of a combination of cleaners may reduce aggregate weight and volumetric requirements for such cleaner(s). Utilization of two compositionally different cleaners, such as may be embodied in a granular cleaner of a first composition in combination with a liquid cleaner of a second composition (i.e., in comparison to use of a single cleaner in liquid or solid form, in the absence of an additional cleaner), may reduce overall demand for cleaner by preferably at least about 10%, more preferably at least about 20%, more preferably at least about 25% by weight and/or volume. Additionally, the use of different cleaners will often speed up the cleaning process, since different chemical cleaners will interact with different contaminants at different rates. Importantly, the molecular weight of the cleaning agent will play an important role on the mass of cleaner applied. For example, a chemical cleaner that has a molecular weight of 50 AMU may clean a similar mass of contaminants as a chemical cleaner with a molecular weight of 100 AMU, but only require ½ the total mass applied. The actual cleaning material savings that can be provided by embodiments of the present invention may significantly depend on the actual composition of the contaminants on the filter media. Thus, as described above, it is preferred to perform a laboratory analysis of a filtration media sample prior to determining efficacious types (e.g., chemical compositions), amounts, and dosages of cleaning agents for a particular filter bed.. [0036] The reduction in cleaner(s) necessary for effective dissolution of contaminants further reduces the weight (and costs) associated with the transport and delivery of such additional agents. In one embodiment, a granular cleaner comprises sulfamic acid, and a liquid cleaner comprises formic acid (with application of such cleaners being followed by application of activator comprising hydrogen peroxide). Such combination of cleaners yielded surprising results in the rapid and effective dissolution of a broad range of inorganic contaminants. Other solid and liquid cleaning agents (e.g., acid) combinations may be utilized, such as to promote: (1 ) dissolution or removal of a sufficient amount of inorganic contaminants to allow exposure of the organic contaminants, (2) with limited amount of residual agent(s) left behind in the filtration media, while (3) avoiding damage to the filtration media.

[0037] In one embodiment, a cleaning agent comprises a plurality of cleaning agents, of which any one or more of which may be in granular or liquid form. At least one advantage associated with using a granular cleaning agent includes the delay associated with the granular cleaning agent traversing through the filter media (thereby potentially increasing localized concentration of cleaner), in comparison to use of liquid cleaning agent that may pass through a filter with sufficient speed to limit its effectiveness in removing of inorganic contaminants. In one embodiment, a granular cleaning agent is applied first, followed by application of a liquid cleaning agent to create a cleaning agent slurry that traverses the slowly through the filter. Such slow traversal (relative to a liquid cleaner alone) allows greater time for the cleaning agent to dissolve or otherwise remove inorganic contaminants present in the filtration media.

[0038] In one embodiment, a filter bed comprising water filtration media is at least partially drained (or substantially completely drained) of water prior to application of the cleaning agent(s). A granular cleaning agent can be carried through the filter by wetting (e.g., with water or other liquid). Wetting the granular cleaning agent may include backwashing the filtration bed and/or applying water to the granular cleaner. In one embodiment, a wetting agent includes any one or more of water, citric acid, and phosphoric acid. While wetting of the granular cleaning agent allows for increased saturation of the cleaning agent(s) through the filter, such wetting step has the potential to overly dilute the agent(s). In one embodiment, a predetermined (e.g., measured) amount of wetting agent is applied to the filtration media following application of one or more cleaning agents. [0039] In various embodiments, use of a liquid cleaning agent reduces or eliminates the need for wetting with one or more other liquid(s), but such liquid cleaning agent may also be used in conjunction with a wetting step including use of at least one other liquid. Application of a liquid cleaning agent to a granular cleaning agent without a wetting step may lessen the extent of dilution of one or more of the granular and liquid cleaning agents. Utilizing a combination of granular and liquid cleaning agents, including cleaning agents having different compositions, broadens the scope of contaminants that can be dissolved and allows for faster dissolution in comparison with a granular agent alone - even when combined with a wetting step.

[0040] Compatibility of granular and liquid cleaning agents may depend on a number of factors including, but not limited to: the pH of each agent, the molecular structure of each agent, and the reactivity of each agent. In one embodiment, granular sulfamic acid combined with formic acid dissolves a broad range of contaminants beyond the scope of sulfamic acid alone. Moreover, sulfamic acid and formic acid are both organic acids with different molecular structures that have been discovered to be highly compatible and effective in the rapid dissolution of a broad range of inorganic contaminants. Other acids in granular and/or liquid form may be used whether separately from one or more of sulfamic acid and formic acid, or in combination with one or more of sulfamic acid and formic acid.

[0041] In a further aspect, a method of cleaning water filtration media includes (a) applying a first cleaner comprising granular sulfamic acid to the water filtration media, (b) applying a second cleaner comprising formic acid to the water filtration media after step (a), and (c) applying an activator to the water filtration media after step (b). In one embodiment, a method of cleaning water filtration media includes the following agents (w/w): sulfamic acid at 1 pound per cubic foot of filtration media, formic acid at 0.5 pounds per cubic foot of filtration media, and hydrogen peroxide at about 1 gallon per 15 cubic feet of filtration media. In another embodiments, the foregoing amounts of agents are minimum threshold values, such that higher amounts of one or more agents (e.g., sulfamic acid of at least one pound per cubic foot, formic acid of at least 0.5 pounds per cubic foot, and hydrogen peroxide of at least one gallon per 15 cubic feet.

[0042] In one embodiment, the activator comprises any one or more of hydrogen peroxide and peracetic acid. An activator may include one or more additional or alternative components (as detailed below) including, but not limited to, oxygen donors, surfactants, corrosion inhibitors, dyes, buffers, and/or carrier media (e.g., water). In one embodiment, a cleaning method further comprises rinsing (or backwashing) from the water filtration media any one or more of the first cleaner, the second cleaner, and the activator.

[0043] In a still further aspect, a method of cleaning water filtration media includes (a) applying a granular cleaner to the water filtration media; (b) applying a liquid cleaner to the water filtration media after step (a); (c) applying an activator to the water filtration media after step (b); and (d) after any one or more of steps (a), (b), and (c), agitating at least a portion of the water filtration media.

[0044] Agitation of at least a portion of the water filtration media may be accomplished by any physical, mechanical, or other known means of putting the filtration media into motion by shaking, stirring, bubbling, etc. Agitation may beneficially provide greater agent access to contaminants and promote reduction in size of contaminant clumps. In certain instances, a filter bed may already include a built-in air scouring system. An air scouring system may be periodically activated (i.e., turned on) to facilitate mixing and/or penetration of chemicals within the filter bed.

[0045] In addition to cleaners and activators, additional constituents may be included in various embodiments. Such additional constituents would preferably be certified as safe for use in drinking water processing installations by the National Science Foundation ("NSF"). Additional constituents can include, but are not limited to, free flow additives, surfactants, corrosion inhibitors, buffers, and coloring agents. The free flow additives may include inert additives that inhibit clumping of the granular cleaner. Surfactants may include any one or more anionic, cationic, non- ionic and amphoteric surfactants such as alkali metal salts, ammonium salts, amine salts, aminoalcohol salts, fatty acid salts, isopropanol, and isobutanol. Corrosion inhibitors include any one or more of nitrogen containing organic compounds, such as amines, quaternary ammonium compounds, heterocyclic nitrogen compounds, urea, thiourea, amide, Inhibitor 60S that is commercially available from Alchem Chemical Company, USA, and P3^® Rodine^® that is commercially available from Henkel Corporation, USA. Coloring agents may include any dye safe for use in drinking water processing installations such as Acid Red LX-6515 that is commercially available from Pylam Products Company, Inc., USA. [0046] In one embodiment, a cleaning agent including granular sulfamic acid may be applied to the filtration media, followed by application of a liquid cleaner including formic acid. In a further embodiment, a granular and/or liquid cleaner may includes at least one additional component selected from the group comprising citric acid, phosphoric acid, corrosion inhibitor, free-flow additive, and surfactant.

[0047] Advantages and features of the invention further illustrated with reference to the following examples, which are not to be construed as in any way limiting the scope of the disclosure but rather as illustrative of various embodiment of the disclosure in specific application thereof.

[0048] FIG. 1 is a schematic flow chart disclosing a method of cleaning filtration media including a first step 10 of applying a granular cleaner, followed by a second step 14A of applying a first discrete dose of activator, followed by a third step 14B of applying a second discrete dose of activator at a predetermined time following the first dose, followed by a fourth step 14C of applying a third discrete dose of activator at a predetermined time following the second dose, followed by a fifth step 16 of rinsing (or backwashing) the filtration media and/or filtration bed to remove any one or more of the granular cleaner and activator.

[0049] Unless specifically indicated to the contrary, the terms "first, second, third, and fourth" as used herein in application to method steps does not necessarily indicate temporal order in which the steps must be performed. Additional method steps may be performed before, after, or between specified method steps unless specifically indicated to the contrary herein.

[0050] The method disclosed in FIG. 1 may further comprise taking a core sample from the water filtration bed, wherein the sample is analyzed to determine an amount of at least one of the granular cleaner and the activator effective for contaminant removal. Such analysis may also be used to determine dosing time. Taking and analyzing of the sample may precede either or both steps of applying a granular cleaner and application of first discrete dose of activator.

[0051] In one embodiment, the method of FIG. 1 includes wetting the granular cleaning agent with a wetting agent following application of the granular cleaner, wherein the wetting agent comprises any one or more of water, citric acid, and phosphoric acid. The method of FIG. 1 in one embodiment includes a granular cleaner comprising a granular acid (e.g., sulfamic acid) and an activator comprising any one or more of hydrogen peroxide and peracetic acid. [0052] FIG. 2 is a schematic flow chart disclosing a method of cleaning filtration media including a first step 20 of applying a granular cleaner reactive with at least one inorganic contaminant, followed by a second step 22 of applying a liquid cleaner compositionally different from the granular cleaner and reactive with at least one inorganic contaminant, followed by a third step 24 of applying an activator reactive with an organic contaminant, followed by a fourth step 26 of rinsing (or backwashing) the water filtration media to remove any one or more of the granular cleaner, liquid cleaner, and activator. In one embodiment, the granular cleaner is reactive with at least one first inorganic contaminant is different from the at least one second inorganic contaminant with which the liquid cleaner is reactive, with the combination of cleaners enabling removal of a greater breadth of inorganic contaminants, and at a greater speed, than could be removed with a single cleaner alone.

[0053] The method disclosed in FIG. 2 may further comprise taking a core sample from the water filtration bed, wherein the sample is analyzed to determine an amount of at least one of the granular cleaner, liquid cleaner, and the activator effective for contaminant removal. Such analysis may also be used to determine dosing time. Taking and analyzing of the sample may precede any one or more of the steps of applying a granular cleaner, applying a liquid cleaner, and applying an activator.

[0054] In one embodiment, the method of FIG. 2 includes wetting the granular cleaning agent with a wetting agent following application of the granular cleaner 20, wherein the wetting agent comprises any one or more of water, citric acid, and phosphoric acid. The method of FIG. 2 in one embodiment includes a granular cleaner comprising a granular acid (e.g., sulfamic acid), a liquid cleaner comprising formic acid, and an activator that comprises any one or more of hydrogen peroxide and peracetic acid.

[0055] FIG. 3 is a schematic flow chart disclosing a method of cleaning filtration media including applying a first cleaner comprising granular sulfamic acid 30, followed by applying a second cleaner comprising formic acid 32, followed by applying an activator 34, followed by rinsing (or backwashing) the filtration media 36 to remove any one or more of the first cleaner, the second cleaner, and the activator. [0056] The method disclosed in FIG. 3 may further comprise taking a core sample from the water filtration bed, wherein the sample is analyzed to determine an amount of at least one of the first cleaner, second cleaner, and the activator effective for contaminant removal. Such analysis may also be used to determine dosing time. Taking and analyzing of the sample may precede any one or more of the steps of applying a first cleaner 30, applying a second cleaner 32, and applying an activator 34.

[0057] In one embodiment, the method of FIG. 3 includes wetting the granular cleaning agent with a wetting agent following application of the first cleaner 30, wherein the wetting agent comprises any one or more of water, citric acid, and phosphoric acid. The method of FIG. 3 in one embodiment includes an activator that comprises any one or more of hydrogen peroxide and peracetic acid.

[0058] FIG. 4 is a schematic flow chart disclosing a method of cleaning filtration media including a first step 40 of applying a granular cleaner, followed by a second step 42 of applying a liquid cleaner, followed by a third step 44 of applying an activator, with the method including a fourth step 46 of agitating the filter (i.e., filtration media and/or filtration bed) following any one or more of the preceding steps to aid in breaking apart and/or exposing contaminants.

[0059] The method disclosed in FIG. 4 may further comprise taking a core sample from the water filtration bed, wherein the sample is analyzed to determine an amount of at least one of the granular cleaner, liquid cleaner, and the activator effective for contaminant removal. Such analysis may also be used to determine dosing time. Taking and analyzing of the sample would precede any one or more of the first step 40 of applying a granular cleaner, the second step 42 of applying a liquid cleaner, and the third step 44 of applying an activator.

[0060] In one embodiment, the method of FIG. 4 includes wetting the granular cleaning agent with a wetting agent following application of the granular cleaner 40, wherein the wetting agent comprises any one or more of water, citric acid, and phosphoric acid. The method of FIG. 4 in one embodiment includes a granular cleaner comprising a granular acid (e.g., sulfamic acid), a liquid cleaner comprising formic acid, and an activator that comprises any one or more of hydrogen peroxide and peracetic acid.

[0061] FIG. 5 is a schematic flow chart disclosing steps of a method including sampling and analysis of filtration media, determination of agents suitable for cleaning the filtration media based on the analysis, and cleaning the filtration media employing agent(s) according to the determination. A first step 100 includes obtaining at least one sample of filtration media, preferably including extracting at least one core sample of the filtration media. A second step 101 includes analyzing the sample(s) to assess the presence, quantity, and/or encapsulation of one or more contaminants. A third step 102 includes determining composition, quantity, and/or dosing of one or more agents to clean the filtration media (e.g., to a desired degree of effectiveness) based on the analyzing step. Subsequent cleaning step(s) 110 include cleaning the filtration media based on the results of the determining step 102, with such cleaning step(s) including any combination of steps as disclosed previously herein (e.g., in connection with FIGS. 1 -4 and/or the detailed description). Such cleaning steps may optionally include any of multiple cleaners (e.g., compositionally different cleaners of solid and/or liquid variety), multiple doses of one or more activators, one or more rinsing (or backwashing) steps, and/or one or more agitation steps as disclosed herein. Cleaning steps may be repeated as necessary to provide a desired degree of cleaning effectiveness. Optionally, after the cleaning step(s) 1 10 are completed, the degree of cleaning may be validated by assessing flow and/or pressure drop performance of the filter bed, and/or extracting and analyzing one or more samples (e.g., core samples) of the filtration media. If necessary, additional one or more cleaning steps may be performed after the validation step.

[0062] Any one or more features and elements as disclosed herein are contemplated for use in combination with one or more other features and elements herein, regardless of whether such features are disclosed in connection with different embodiments, absent indication to the contrary herein.

[0063] While the invention has been has been described herein in reference to specific aspects, features and illustrative embodiments of the disclosure, it will be appreciated that the utility of the disclosure is not thus limited, but rather extends to and encompasses numerous other variations, modifications and alternative embodiments, as will suggest themselves to those of ordinary skill in the field of the present invention, based on the disclosure herein. It is to be appreciated that any of the elements and features described herein may be combined with any one or more other elements and features. Correspondingly, the disclosure as hereinafter claimed is intended to be broadly construed and interpreted, as including all such variations, modifications and alternative embodiments, within its spirit and scope.

Claims

CLAIMS What is claimed is:

1. A method of removing contaminants from water filtration media, the method comprising:

(a) applying a granular cleaner to the water filtration media; and

(b) applying multiple discrete doses of an activator to the water filtration media at predetermined time intervals.

2. The method of claim 1 , further comprising applying a liquid cleaner to the water filtration media.

3. The method of claim 2, wherein the liquid cleaner comprises a liquid acid.

4. The method of claim 3, wherein the liquid acid comprises formic acid.

5. The method of claim 1 , wherein the granular cleaner comprises a granular acid.

6. The method of claim 5, wherein the granular acid comprises sulfamic acid.

7. The method of claim 1 , wherein the activator comprises any one or more of hydrogen peroxide and peracetic acid.

8. The method of any one of claims 1 to 7, further comprising obtaining a core sample of the water filtration media.

9. The method of claim 8, further comprising analyzing the core sample to determine an amount of at least one of the granular cleaner and the activator effective for contaminant removal.

10. The method of any one of claims 1 to 7, further comprising agitating at least a portion of the water filtration media.

1 1. The method of any one of claims 1 to 7, further comprising wetting the granular cleaner with a wetting agent.

12. The method of claim 11 , wherein the wetting agent comprises any one or more of water, citric acid, and phosphoric acid.

13. The method of any one of claims 1 to 7, further comprising rinsing or backwashing from the water filtration media any one or more of the granular cleaner and the activator.

14. The method of any one of claims 1 to 7, wherein the multiple discrete doses comprise at least three doses.

15. The method of any one of claims 1 to 7, wherein at least one predetermined time interval comprises at least one hour.

16. The method of any one of claims 1 to 7, wherein step (b) is performed after step (a).

17. A method of cleaning water filtration media, the method comprising:

(a) applying a granular cleaner to the water filtration media, wherein the granular cleaner is reactive with at least one inorganic contaminant;

(b) after step (a), applying a liquid cleaner to the water filtration media, wherein the liquid cleaner is compositionally different from the granular cleaner and is reactive with at least one inorganic contaminant; and

(c) after step (b), applying an activator to the water filtration media, wherein the activator is reactive with at least one organic contaminant.

18. The method of claim 17, further comprising obtaining a core sample of the water filtration media.

19. The method of claim 16, further comprising analyzing the core sample to determine an amount of at least one of the granular cleaner and the activator effective for contaminant removal.

20. The method of any one of claims 17 to 19, further comprising agitating at least a portion of the water filtration media.

21. The method of any one of claims 17 to 19, further comprising wetting the granular cleaner with a wetting agent.

22. The method of claim 21 , wherein the wetting agent comprises any one or more of water, citric acid, and phosphoric acid.

23. The method of any one of claims 17 to 19, further comprising rinsing or backwashing from the water filtration media any one or more of the granular cleaner, the liquid cleaner, and the activator.

24. The method of any one of claims 17 to 19, wherein the applying of activator comprises multiple discrete doses of an activator to the water filtration media at predetermined time intervals.

25. The method of claim 24, wherein the multiple discrete doses comprise at least three doses.

26. The method of claim 24, wherein at least one predetermined time interval comprises at least one hour.

27. The method of any one of claims 17 to 19, wherein the granular cleaner comprises sulfamic acid.

28. The method of any one of claims 17 to 19, wherein the liquid cleaner comprises formic acid.

29. The method of any one of claims 17 to 19, wherein the activator comprises any one or more of hydrogen peroxide and peracetic acid.

30. A method of cleaning water filtration media, the method comprising:

(a) applying a first cleaner comprising granular sulfamic acid to the water filtration media;

(b) after step (a), applying a second cleaner comprising formic acid to the water filtration media; and

(c) after step (b), applying an activator to the water filtration media.

31. The method of claim 30, wherein the activator comprises at least one of hydrogen peroxide and peracetic acid.

32. The method of claim 30, further comprising obtaining a core sample of the water filtration media.

33. The method of claim 32, further comprising analyzing the core sample to determine an amount of at least one of the first cleaner, second cleaner, and the activator effective for contaminant removal.

34. The method of any one of claims 30 to 33, further comprising agitating at least a portion of the water filtration media.

35. The method of any one of claims 30 to 33, further comprising wetting the first cleaner with a wetting agent.

36. The method of claim 35, wherein the wetting agent comprises any one or more of water, citric acid, and phosphoric acid.

37. The method of any one of claims 30 to 33, further comprising rinsing or backwashing from the water filtration media any one or more of the first cleaner, the second cleaner, and the activator.

38. The method of any one of claims 30 to 33, wherein the applying of activator comprises multiple discrete doses of an activator to the water filtration media at predetermined time intervals.

39. The method of claim 38, wherein the multiple discrete doses comprise at least three doses.

40. The method of claim 38, wherein at least one predetermined time interval comprises at least one hour.

41. A method of cleaning water filtration media, the method comprising:

(a) applying a granular cleaner to the water filtration media;

(b) after step (a), applying a liquid cleaner to the water filtration media;

(c) after step (b), applying an activator to the water filtration media; and

(d) after any one or more of steps (a), (b), and (c), agitating at least a portion of the water filtration media.

42. The method of claim 41 , wherein the activator comprises any one or more of hydrogen peroxide and peracetic acid.

43. The method of claim 41 , further comprising obtaining a core sample of the water filtration media.

44. The method of claim 43, further comprising analyzing the core sample to determine an amount of at least one of the granular cleaner and the activator effective for contaminant removal.

45. The method of any one of claims 41 to 44, further comprising wetting the granular cleaner with a wetting agent.

46. The method of claim 45, wherein the wetting agent comprises any one or more of water, citric acid, and phosphoric acid.

47. The method of any one of claims 41 to 44, further comprising rinsing or backwashing from the water filtration media any one or more of the granular cleaner, the liquid cleaner, and the activator.

48. The method of any one of claims 41 to 44, wherein the applying of activator comprises multiple discrete doses of an activator to the water filtration media at predetermined time intervals.

49. The method of claim 48, wherein the multiple discrete doses comprise at least three doses.

50. The method of claim 48, wherein at least one predetermined time interval comprises at least one hour.

51. The method of any one of claims 41 to 44, wherein the granular cleaner comprises sulfamic acid.

52. The method of any one of claims 41 to 44, wherein the liquid cleaner comprises formic acid.