WO2022129957A1

WO2022129957A1 - Method and system for disinfecting water for animal consumption

Info

Publication number: WO2022129957A1
Application number: PCT/GB2021/053380
Authority: WO
Inventors: Yongjun Chen; Mingxing GAO; Xiaofeng Yang; Chunjin ZHANG
Original assignee: Strix Limited; Halosource Water Purification Technology (Shanghai) Co. Ltd
Priority date: 2020-12-18
Filing date: 2021-12-20
Publication date: 2022-06-23

Abstract

A system (200) for disinfecting water for animal consumption, the system comprising a disinfection unit (400, 402) comprising a number n (n≥1) of water disinfection cartridges. Each water disinfection cartridge comprises a first medium including a releasable biocidal species that is released into the first water supply coming into contact with the first medium to provide a disinfected water supply having a first concentration of the biocidal species. The disinfected water supply is passed into a balance tank (1000), the balance tank (1000) comprising a second medium including the releasable biocidal species, arranged to be available to be released at a release rate into the disinfected water supply coming into contact with the second medium. The second medium includes vacant binding sites, arranged to reversibly bind at an absorption rate with the biocidal species in the disinfected water supply coming into contact with the second medium. A ratio of the absorption rate to the release rate of the second medium determines an adjustment effect that the balance tank (1000) has on the first concentration of biocidal species in the disinfected water supply to achieve a second concentration of the biocidal species in a balanced water supply output from the balance tank (1000).

Description

METHOD AND SYSTEM FOR DISINFECTING WATER FOR ANIMAL CONSUMPTION

Background

Provision of clean drinking water for animals, particularly poultry, has a significant impact on animal health and performance, such as growth rate, feed conversion, health or egg production. Poultry farms may source raw water from a variety of water sources such as the municipal water, underground water or even surface water and rain water, all of which may have varying degrees of microbial contamination. Furthermore, biofilm may form in drinking lines which protects pathogenic microbes. Regardless of the source, it is important that the water be decontaminated before being supplied for animal consumption as microbes present in drinking water may make the animals sick. Additionally, some microorganisms can decrease the effectiveness of medications and vaccines that may be dispensed through the water supply. However, decontamination of pathogenic microorganisms from raw water, and biofilm build-up in water pipelines, present a challenge for provision of clean water. It is thus an object of the present invention to address some of these challenges.

A biofilm is a slime attached to a surface which encapsulates bacteria, fungi and algae in an extracellular polysaccharide and other organic compounds. Biofilms therefore serve a dual role of providing a breeding ground for microorganisms to multiply and protecting the microorganisms from biocidal agents. Biofilm formation is prevalent in slow-flowing water systems where adequate nutrients are present, such as nipple drinker systems in animal houses. Additionally, farms often add additives to animal drinking water that may be used as a food source for biofilm to promote growth. These additives include flavored gelatin mixes, powdered drink mixes, vitamins, electrolytes, sugar water, stabilizers, antibiotics, etc. Once a biofilm is formed it is difficult to eradicate, making the cleaning and maintenance of a clean water supply challenging.

Water sanitation is well known to be crucial to effectively combat the presence of microbes and biofilm build-up in animal (e.g. poultry) drinking systems. The aim of water disinfection is to eliminate pathogens that might be in the water, both those originated from contamination of the water source and those pathogens that might be added to the water, e.g. if infected animals have access to water in the drinkers. It is therefore known to provide residual levels of disinfectant, such as chlorine, in the drinking water lines to help eliminate such pathogens. Several water sanitization options have been widely practised in the poultry industry. Ultrafiltration (UF) is a membrane filtration process that serves as a barrier to separate harmful bacteria, viruses, and other contaminants from contaminated water. This technology has been developed to effectively remove the pathogens from the supplied raw water, however, it is not available to deliver a disinfectant residual throughout the water distribution pipeline. Another common option in the field is to manually dose disinfection chemicals into water system, such as household bleach, sodium hypochlorite, hydrogen peroxide, stabilized hydrogen peroxide, or chlorine dioxide et al.

Chlorine products have been the prime water disinfectant products for many years in the poultry industry. In poultry operations, the commonly used chlorine sources for poultry drinking water sanitation are sodium hypochlorite, elemental chlorine gas and calcium hypochlorite. Because chlorination is more effective at lower pH (commonly below 6.5), drinking water is often needed to be acidified to support chlorine disinfectant efficacy for improved sanitizing residual (which supports better bird performance). However, careful selection among various acid products available is necessary to avoid water consumption impacts. When using chlorine and acidifiers together in water, they should be mixed and injected separately to avoid poisonous gas formation. Chlorine’s sanitization efficacy is greatly reduced by the inorganic and organic nitrogen-containing contaminants from the poultry water system. Additionally, there is concern that microbes may develop resistance to chlorine products if they have not been used properly.

Iodine products are also known as water disinfectant products. In some disinfectant systems solid iodine is used, where water is passed through a column of crystalline (solid) iodine to dissolve the iodine and obtain a highly saturated aqueous solution of iodine which may then be diluted to achieve a desired and constant concentration of iodine. In other systems, an iodinated anion-exchange resin is used, where I2, tri-, penta- and hepta-iodine anions are attached to quaternary ammonium, styrene-divinyl benzene, cross-linked anion-exchange resins. Drinking water contains various types of anions (e.g. negatively charged microorganisms), that are thus attracted to the positively charged polyquarternary ammonium moiety which then releases iodine to kill the microorganism. However, not all negatively charged species within drinking water are harmful but are indiscriminately attracted to the positively charged resin, resulting in a reduction in the biocidal efficacy of the iodinated anion-exchange resin and highly variable concentration of iodine residual.

It has been recognised that, other than microorganisms, real water generally contains a number of negatively charged contaminants, such as natural organic matters (NOMs), e.g. humic acid, fulvic acid, and tannic acid, and colloidal silica. When iodinated resin is placed into a cartridge to allow water flow through, these negatively charged contaminants would also be attracted by positively charged resin polymer and further attached onto the surface of resin, therefore those contaminants may result in a significant biocidal efficacy reduction when iodinated resin is used in real and highly contaminated drinking water disinfection.

The safety of long-term consumption of iodine when used as a drinking-water disinfectant is not established according to “Iodine as a drinking water disinfectant”, WHO 2018, ISBN 978- 92-4-151369-2. Higher concentrations are required as compared to chlorine to achieve comparable disinfection efficacy.

A routine and simple operation of maintaining water line system cleaning known in the industry is to conduct routine flushing. Flushing helps wash away potential food sources for bacteria or other organisms. However, frequent water line flushing increases maintenance costs (e.g., labour costs, water costs and wastewater discharge costs, etc.). An effective water sanitization operation reduces the flushing frequency if biofilm growth in the water line system has been greatly prohibited. However, such systems require the drinking supply to be shut off from the drinking lines and thus the effectiveness of flushing or disinfecting for a prolonged period must be balanced with the requirement that animals not be without a water supply for an extended period of time. This often results in disinfection occurring at night when the demand for drinking water is lowest and may result in less effective disinfection.

An object of the present invention is thus to provide improved water treatment systems and methods providing effective disinfection, in particular for treating water for animal consumption.

US 2003/0044378, US 2004/0086480 and US 2012/0035284, the entire contents of which is incorporated herein by reference, disclose biocidal halogenated polystyrene hydantoin particles. The cross-linked and porous halogenated polystyrene hydantoin beads, also referred to as HaloPure™, are a contact biocide bead that has been applied to human drinking water systems. Biocidal activity is believed to be a result of surface contact of organisms with chlorine or bromine moieties covalently bound to the hydantoin functional groups of the polymer. However, continuous controlled and consistent dosage of biocidal chlorine or bromine is difficult to achieve over long periods of time without regular replacement of the expensive HaloPure™ cartridges, which is economically unattainable for animal (e.g. poultry) farm use. Thus, an additional object of the present invention is the provision of a cost-effective system and method that may incorporate the HaloPure™ technology or similar to treat water for animal consumption.

Statements of Invention

When viewed from a first aspect the invention provides a system for disinfecting water for animal consumption, the system comprising: a disinfection inlet arranged to bring a first water supply to a disinfection unit; the disinfection unit comprising a number n (n>1) of water disinfection cartridges, wherein each water disinfection cartridge comprises a first (e.g. polymeric) medium including a releasable biocidal (e.g. halogen) species that is released into the first water supply coming into contact with the first (e.g. polymeric) medium to provide a disinfected water supply, wherein the disinfected water supply has a first concentration of the biocidal (e.g. halogen) species; a balance tank inlet arranged to bring the disinfected water supply to a balance tank; the balance tank comprising a second (e.g. polymeric) medium including: the releasable biocidal (e.g. halogen) species, arranged to be available to be released at a release rate into the disinfected water supply coming into contact with the second medium; and vacant binding sites, arranged to reversibly bind at an absorption rate with the biocidal (e.g. halogen) species in the disinfected water supply coming into contact with the second (e.g. polymeric) medium; wherein a ratio of the absorption rate to the release rate defines a rate ratio of the second (e.g. polymeric) medium; and wherein the rate ratio of the second (e.g. polymeric) medium determines an adjustment effect that the balance tank has on the first concentration of biocidal (e.g. halogen) species in the disinfected water supply to achieve a second concentration of the biocidal (e.g. halogen) species in a balanced water supply output from the balance tank.

Such a system may be present at any time during its ongoing use to adjust the first concentration of the biocidal species in the disinfected water supply to give a desired second concentration, i.e. the system at a time t > to. The balance tank can therefore act to reduce/maintain/increase the first concentration of biocidal (e.g. halogen) species in the disinfected water supply to achieve a lower/equal/higher second concentration of the biocidal (e.g. halogen) species in a balanced water supply output from the balance tank, as is described in more detail below. However, it may be appreciated that the biocidal halogen species in the second (e.g. polymeric) medium at an initial time to (e.g. before water has been arranged to pass through the disinfection unit, e.g. at the point of installation) may be substantially zero, e.g. there is 0 percentage by weight (wt%) of the biocidal species present in the second (e.g. polymeric) medium. As such, in these embodiments the second (e.g. polymeric) medium only comprises vacant binding sites, arranged to reversibly bind at an absorption rate with the biocidal species in the disinfected water supply coming into contact with the second (e.g. polymeric) medium, such that the second (e.g. polymeric) medium is suitable for including the releasable biocidal (e.g. halogen) species. This system at an initial time to may be considered to represent an alternative aspect of the present invention.

According to a second aspect of the present invention of the present invention there is provided a system for disinfecting water for animal consumption, the system comprising: a disinfection inlet arranged to bring a first water supply to a disinfection unit; the disinfection unit comprising a number n (n>1) of water disinfection cartridges, wherein each water disinfection cartridge comprises a first (e.g. polymeric) medium including a releasable biocidal (e.g. halogen) species that is released into the first water supply coming into contact with the first (e.g. polymeric) medium to provide a disinfected water supply, wherein the disinfected water supply has a first concentration of the biocidal (e.g. halogen) species; a balance tank inlet arranged to bring the disinfected water supply to a balance tank; the balance tank comprising a second (e.g. polymeric) medium; the second (e.g. polymeric) medium suitable for including the releasable biocidal (e.g. halogen) species, wherein the releasable biocidal (e.g. halogen) species is arranged to be available to be released at a release rate into the disinfected water supply coming into contact with the second (e.g. polymeric) medium; and the second (e.g. polymeric) medium including vacant binding sites, arranged to reversibly bind at an absorption rate with the biocidal (e.g. halogen) species in the disinfected water supply coming into contact with the second (e.g. polymeric) medium; wherein a ratio of the absorption rate to the release rate defines a rate ratio of the second (e.g. polymeric) medium; and wherein the rate ratio of the second (e.g. polymeric) medium determines an adjustment effect that the balance tank has on the first concentration of biocidal (e.g. halogen) species in the disinfected water supply to achieve a second concentration of the biocidal (e.g. halogen) species in a balanced water supply output from the balance tank. In such a system, typically at an initial time to, there is no releasable biocidal (e.g. halogen) species yet available to be released at a release rate into the disinfected water supply coming into contact with the second medium. The balance tank can therefore act only to reduce the first concentration of biocidal (e.g. halogen) species in the disinfected water supply to achieve a lower second concentration of the biocidal (e.g. halogen) species in a balanced water supply output from the balance tank.

It will also be appreciated that, at a time greater than to (e.g. after water has been bought into contact with the first and/or second medium), the balance tank (e.g. that initially comprised only vacant binding sites) may absorb biocidal (e.g. halogen) species present in the disinfected water supply such that, when t>tO, the second medium includes > 0 wt% of the releasable biocidal species as well as vacant binding sites. A just-installed system according to the second aspect of the invention may then become a system according to the first aspect of the invention during its operation.

The inventors have recognised that the rate of release of the biocidal (e.g. halogen) species from the first (e.g. polymeric) medium into the first water supply can be variable. For example, the rate of release may vary as the total volume of water that has passed through the disinfection cartridges increases. For example, the first concentration of the biocidal species in the disinfected water supply typically decreases gradually during prolonged exposure across the lifetime of each cartridge. It will therefore be appreciated that, in some circumstances the first concentration of the biocidal species may be too high (e.g. resulting in an unnecessary consumption of the releasable biocidal species from the first medium), whilst in other circumstances the first concentration may be too low for an efficacious disinfection effect. The inventors have realised that the provision of a balance tank, in fluid communication with and downstream of the disinfected water supply, provides a means by which the first concentration of the biocidal species in the disinfected water supply may be adjusted (e.g. increased, decreased or maintained) to give a desired second concentration, e.g. one that meets the needs of a given delivery system for animal consumption. The system can be used to provide an efficacious level of the biocidal species in the balanced water supply, e.g. to inactivate pathogens and to potentially control or prevent biofilm formation, as is explained further below.

Within the meaning of the present invention, the term biocidal species means a chemical substance (e.g. molecules, molecular salts, ions etc.) having the effect of destroying, deterring, suppressing, rendering harmless, or exerting a controlling effect on any harmful organism, microbe or microorganism (i.e. pathogen). The biocidal species may be defined as having such an effect on one or more pathogens affecting the health of humans and/or animals, including Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli, Candida albicans, Klebsiella terrigena, Legionella pneumophila and rotavirus in water. This means that these harmful organisms can be killed or neutralised by the biocidal species upon contact.

In various embodiments, the biocidal species released by the first and second media comprises oxidative halogen, for example oxidative chlorine, for example oxidative bromine (e.g. Br⁺). In preferable embodiments, the first and second media include biocidal halogenated (e.g. chlorinated, e.g. brominated) polymer resin beads.

Within the meaning of the present invention, the term releasable biocidal species when used in reference to a medium (e.g. the first medium, e.g. the second medium, e.g. a third medium) means that the biocidal species is chemically bound to the medium but non- covalently bound. This means that the non-covalent bond may be broken with low enthalpy and the biocidal species dissociates from the medium to be released into the water supply coming into contact with the medium. An example of such a dissociation mechanism is described later below.

Alternatively, within the meaning of the present invention, the term releasable biocidal (e.g. halogen) species when used in reference to a medium (e.g. a first/second/third medium, preferably a polymeric medium) means that the biocidal species is covalently bound to the medium. For example, the biocidal (e.g. halogen) species may be covalently bound to a functional group of the polymeric medium, preferably to a hydantoin functional group of the polymeric medium. Even though the biocidal (e.g. halogen) species is covalently bound to the medium, the covalent bond has a sufficiently low bond enthalpy that the covalent bond may be broken when in the presence of water and the biocidal (e.g. halogen) species dissociates from the (e.g. polymeric) medium to be released into the water supply coming into contact with the medium. An example of such a dissociation mechanism is described later below.

It has been appreciated that, by chemically binding the biocidal (e.g. halogen) species to the medium, at least some of the limitations of an anion-exchange resin (discussed above) are addressed (i.e. the efficacy is improved and the concentration of residual biocidal species in the water is predictable). It will be appreciated that dissolving a solid biocidal species (e.g. iodine crystals) into a water source does not constitute a releasable biocidal species as there is no dissociation of a covalent bond from a separate medium (e.g. a polymeric first/second/third medium). Within the meaning of the present invention, the vacant binding sites being arranged to reversibly bind with the biocidal (e.g. halogen) species means that a reversible (e.g. covalent) bond is formed with the second medium that is readily broken (e.g. dissociated) when in the presence of water. For a reversible covalent bond, the free energy difference between the non-bonded species and the covalently bound species is sufficiently similar such that the two states (e.g. bound and unbound) are substantially in equilibrium, and the activation barrier for breaking (or making) the covalent bond is sufficiently low that the covalent bond may be dissociated in the presence of water. For example, the second (e.g. polymeric) medium is able to reversibly (e.g. covalently) bind to the biocidal (e.g. halogen) species such that when there is (e.g. an excess of) biocidal (e.g. halogen) species in the disinfected water supply, the biocidal (e.g. halogen) species may be absorbed by vacant binding sites forming a reversible (e.g. covalent bond) with the biocidal (e.g. halogen) species. Similarly, for example, when there is a sufficiently low (e.g. zero) concentration of biocidal (e.g. halogen) species in the disinfected water supply (e.g. when the amount of biocidal species drops below a threshold amount), the biocidal (e.g. halogen) species reversibly (e.g. covalently) bound to the second (e.g. polymeric) medium may be released (e.g. by breaking the covalent bond with the biocidal (e.g. halogen) species in the presence of water).

Within the meaning of the present invention, the term disinfected water supply means a water supply that has come into contact with a medium that includes a releasable biocidal species (as defined above) such that the disinfected water supply may be characterised as having been treated by the biocidal species to destroy pathogens.

The first concentration of the biocidal species in the disinfected water supply may be relatively low, e.g. following interaction between the biocidal species and pathogens in the first water supply. This means that there may not remain a sufficient residual level of the biocidal species in the disinfected water supply to provide a disinfection effect downstream. However, in some embodiments the first concentration of the biocidal (e.g. halogen) species is selected for the disinfected water supply to provide a residual disinfection effect resulting from a residual level of the biocidal (e.g. halogen) species present in the disinfected water supply, i.e. an ongoing disinfection effect. This residual level of the biocidal (e.g. halogen) species can control or prevent formation of biofilms in supply lines carrying the disinfected water supply.

The inventors have recognised that another fluctuation relevant to a system used to treat water for animal consumption is the flow rate of water through the system. There can be a wide variation in demand for drinking water in a farm, e.g. at different times of the day and night.

The inventors have recognised that, by providing a second (e.g. polymeric) medium within the balance tank that includes (or is suitable for including) the releasable biocidal (e.g. halogen) species (e.g. the same releasable biocidal (e.g. halogen) species which is released by the first medium) as well as vacant binding sites which are available to reversibly bind to biocidal (e.g. halogen) species which are present within the water supply (e.g. the disinfected water supply) coming into contact with the second (e.g. polymeric) medium, the balance tank is able to both release additional biocidal (e.g. halogen) species into the disinfected water supply as well as absorb excess biocidal species from the disinfected water supply, to thereby exert an adjustment effect on the first concentration of the biocidal species in the disinfected water supply to achieve the desired second concentration of the biocidal species in the balanced water supply. This absorption and release may take place at the same time or at different times. The second concentration may therefore reach a desired concentration more accurately than the first concentration, e.g. the tolerance levels of the second concentration may be smaller than for the first concentration. The adjustment effect of the balance tank can act to even out fluctuations in the first concentration, for example a first concentration of 1.0 ± 0.5 ppm (i.e. a tolerance level of 0.5 ppm) may be adjusted to a second concentration of 1.0 ± 0.1 ppm (i.e. a tolerance level of 0.1 ppm).

Within the meaning of the present invention, the term adjustment effect means the average (e.g. net) change in the first concentration that results after the disinfected water supply passes through the balance tank to provide the balanced water supply with the second concentration of the biocidal species. Thus the adjustment effect (e.g. increased concentration, e.g. decreased concentration, e.g. maintained concentration) may be considered to be the net difference between the first and second concentrations of the biocidal species.

Although the adjustment effect defines the overall net change in the concentration of the biocidal species, it will be appreciated that the balance tank works by simultaneously absorbing and releasing the biocidal species to provide this effect. Thus the adjustment effect is a result of the ratio between the absorption rate of the second medium and the release rate of the second medium, i.e. the rate ratio of the second medium at any given time. In some embodiments, the absorption rate of the second medium may be defined as the rate at which the biocidal species present within a water supply (e.g. the disinfected water supply) coming into contact with the second medium is absorbed from the water supply to be reversibly bound (e.g. non-covalently) to the second medium. The release rate of the second medium may be defined as the rate at which the biocidal species reversibly bound (e.g. non- covalently) to the second medium is released into the water supply (e.g. the disinfected water supply) coming into contact with the second medium. As such, it will be appreciated that the second medium simultaneously acts to both absorb and release the biocidal species at any given time such that the adjustment effect is provided by the one of these processes (e.g. absorption or release) which is occurring at a faster rate.

In some embodiments, the absorption rate of the second medium may be defined as the rate at which the biocidal species present within a water supply (e.g. the disinfected water supply) coming into contact with the second medium is absorbed from the water supply to be reversibly bound (e.g. covalently) to the second medium. The release rate of the second medium may be defined as the rate at which the biocidal species reversibly bound (e.g. covalently) to the second medium is released into the water supply (e.g. the disinfected water supply) coming into contact with the second medium. As such, it will be appreciated that the second medium simultaneously acts to both absorb and release the biocidal species at any given time such that the adjustment effect is provided by the one of these processes (e.g. absorption or release) which is occurring at a faster rate.

It will be appreciated that the rate of absorption of the biocidal species from the disinfected water supply into the second medium may be affected by a variety of factors, including, but not limited to one or more of: the first concentration of the biocidal species, the flow rate of the disinfected water supply passing through the balance tank, and/or the temperature of the disinfected water supply. Similarly, it will be appreciated that the rate of release of the biocidal species from the second medium into the disinfected water supply may be affected by a variety of factors, including, but not limited to one or more of: the concentration (e.g. in weight percent) of the biocidal species bound to the second medium, the temperature of the disinfected water supply, the flow rate of disinfected water supply coming into contact with the second medium, the total volume of water that has come into contact with the second medium since an initial time, and the first concentration of the biocidal species present in the disinfected water supply coming into contact with the second medium. Within the meaning of the present invention, the term “flow rate” means the volumetric flow rate, i.e. the volume of water which passes per unit time. This may be measured in in Metric Tonnes per hour (MT/hr).

The inventors have thus appreciated that the balance tank is able to effect an adjustment of the first concentration of the biocidal species based on the rate ratio of the second medium. The rate ratio is defined as a ratio of the absorption rate to the release rate (e.g. the absorption rate divided by the release rate).

In some embodiments, when the absorption rate is greater than the release rate, the rate ratio is greater than one and the balance tank adjusts the first concentration such that the second concentration of the biocidal species is lower than the first concentration of the biocidal species. For example, the adjustment effect is a net reversible binding (e.g. absorption) effect. In some embodiments, the rate of absorption of the biocidal species into the second medium is greater than the rate of release of the biocidal species from the second medium such that more of the biocidal species is removed from the disinfected water supply than is added and the second concentration of the biocidal species in the balanced water is less than the first concentration of the biocidal species in the disinfected water supply.

In some embodiments, when the absorption rate is less than the release rate, the rate ratio is less than one and the balance tank adjusts the first concentration such that the second concentration of the biocidal species is greater than the first concentration of the biocidal species. For example, the adjustment effect is a net release of the biocidal species. In some embodiments, the rate of absorption of the biocidal species into the second medium is less than the rate of rate of release of the biocidal species from the second medium such that less of the biocidal species is removed from the disinfected water supply than is added and the second concentration of the biocidal species in the balanced water is greater than the first concentration of the biocidal species in the disinfected water supply.

In some embodiments, wherein, when the absorption rate is equal to the release rate, the rate ratio is equal to one and the adjustment effect is that the second concentration of the biocidal species is substantially the same as the first concentration of the biocidal species. For example, the adjustment effect is a net maintenance of the concentration of the biocidal species due to the absorption (e.g. rate) adjustment being equal to the release (e.g. rate) adjustment. In some embodiments, the rate of absorption of the biocidal species into the second medium is equal to (e.g. balanced with) the rate of release of the biocidal species from the second medium such that the same amount of the biocidal species is removed from the disinfected water supply as is added and the second concentration of the biocidal species in the balanced water is substantially equal to the first concentration of the biocidal species in the disinfected water supply.

It is an advantage of the adjustment effect that, even when the concentration of the biocidal species is maintained without a net change in its average value, a tolerance level associated with the average value may be reduced. This tightening of the tolerance level may apply regardless of whether the first concentration of the biocidal species in the disinfected water supply is increased, decreased or maintained. In at least some embodiments, the second concentration of the biocidal species in the balanced water has a lower tolerance level than the first concentration of the biocidal species in the disinfected water supply. A tolerance level will be understood to represent the range of values encompassing a quoted first/second concentration value. A tolerance level may be statistically defined as a deviation, for example expressed as a standard deviation, standard error, or other statistical measure of deviation from a mean concentration value.

In some embodiments, the second concentration of the biocidal species in the balanced water supply may not provide a sufficient residual level of the biocidal species in the balanced water supply to provide a disinfection effect downstream. However, it has been recognised that there is a benefit to the balanced water supply providing a downstream disinfection effect. In some embodiments, the desired second concentration of the biocidal species is selected for the balanced water supply to provide a residual disinfection effect resulting from a residual level of the biocidal species present in the balanced water supply. As mentioned above, this residual level of the biocidal species can control or prevent formation of biofilms in supply lines carrying the balanced water supply.

Within the meaning of the present invention, the term residual disinfection effect when used in reference to a water supply (e.g. the disinfected and/or balanced water supply) means a water supply which comprises a sufficient concentration of the biocidal (e.g. halogen) species, which has been released into the water supply from a medium positioned upstream (e.g. of the downstream site where the disinfection effect occurs), to destroy, deter, render harmless, or exert a controlling effect on one or more pathogens without the pathogen(s) needing to be present within the water supply when the water supply comes into contact with the upstream medium including the releasable biocidal species. For example, in at least some embodiments, the desired second concentration of the biocidal (e.g. halogen) species in the balanced water supply is between 0.3 ppm and 2 ppm, e.g. between 0.5 ppm and 1.5 ppm. In preferable embodiments, the second concentration of the biocidal species in the balanced water supply is between 0.5 ppm and 1 ppm. In some preferable embodiments, the second concentration of the biocidal species is between 0.5 ppm and 1 ppm, or between 0.8 ppm and 1 ppm or between 0.8 ppm and 1.2 ppm.

Preferably the second concentration of the biocidal species is about 1 ppm. Such concentrations have been found to provide a residual disinfection effect at least when the biocidal species comprises oxidative halogen, in particular oxidative bromine (e.g. Br+).

In some embodiments, the first (e.g. polymeric) medium and the second (e.g polymeric) medium are selected to be substantially the same (e.g. polymeric) medium. In at least some embodiments, each the first medium and/or second medium comprises biocidal halogenated (e.g. brominated) polymer resin beads. In at least some embodiments, the biocidal species released by the first medium and second medium comprises oxidative halogen, for example oxidative bromine (e.g. Br⁺) or oxidative chlorine (Cl⁺). Although the first and second mediums may be substantially the same, it will be understood that the second medium may include a higher number of vacant binding sites than the first medium when the system is first used, i.e. the first medium may be loaded with a greater percentage by weight (wt%) of the biocidal species than the second medium.

In some embodiments, the first (e.g. polymeric) medium includes a greater percentage by weight (wt%) of the biocidal species than the percentage by weight (wt%) of the biocidal species in the second (e.g. polymeric) medium at an initial time to. For example, the first medium comprises a percentage weight (wt%) of the biocidal species available to be released into the water supply (e.g. first water supply) coming into contact with the first medium which is greater than a percentage weight (wt%) of the biocidal species included in the second (e.g. polymeric) medium before water has been arranged to come into contact with either the first (e.g. polymeric) medium or the second (e.g. polymeric) medium. In other words, at the initial time to before the disinfection cartridges and the balance tank have been installed or used (either as new or replenished cartridges). The initial time to may be reset when one or more of the disinfection cartridges are recharged or replaced (as is described further below).

Initial installation or replenishment of the disinfection unit may be used to define an initial time tO, corresponding to a time when the disinfection cartridges are first installed, replaced, made available for use, replenished or recharged, or otherwise representing the start of a working lifetime for one or more of the disinfection cartridges. In at least some embodiments, the initial time to corresponds to a time when the first water supply first starts to flow through the disinfection unit to one or more of the plurality of disinfection cartridges after installation, replacement or recharging. The initial time to may be defined, for one or more of the disinfection cartridges, as the time when the first medium includes its highest or maximum percentage by weight of the biocidal species.

In some embodiments, a water supply may be arranged to pass through the balance tank independently of the disinfection cartridges (e.g. the water supply passing through the balance tank may bypass the disinfection cartridges) such that the balance tank may be selectively depleted of the biocidal species reversibly bound to the second (e.g. polymeric) medium independently of the disinfection cartridges. This process may be carried out prior to implementing the system disclosed herein. In such examples, the second (e.g. polymeric) medium may comprise a percentage by weight (wt%) of the biocidal (e.g. halogen) species available to be released into the water supply that is greater than or equal to the first medium before water has been arranged to come into contact with either the first medium or the second medium. The second medium may thus be selectively depleted of the biocidal (e.g. halogen) species by an independent water supply until the percentage weight (wt%) of biocidal species available to be released into the water supply coming into contact with the second (e.g. polymeric) medium is less than that the percentage weight (wt%) of biocidal species which is available to be released by the first medium. Thus, when the water supply arranged to supply the balance tank comprises the disinfected water supply (e.g. defining the initial time to, the first medium comprises a percentage weight (wt%) of biocidal species available to be released into the water supply (e.g. first water supply) coming into contact with the first medium which is greater than a percentage weight (wt%) of biocidal species included in the second medium.

In one or more examples, the first medium comprises an amount of the biocidal species that is initially released into the first water supply at the initial time to that is between 5 wt% and 90 wt% oxidative halogen, preferably 30-35% oxidative halogen, preferably 30-40 wt% oxidative halogen, for example oxidative bromine. Suitable water disinfection cartridges are described in US 2003/0044378, US 2004/0086480 and US 2012/0035284, the entire contents of which are incorporated herein by reference.

In some embodiments, the first concentration of the biocidal species that is released into the first water supply at the initial time to is between 5 ppm and 15 ppm, preferably 8 to 12 ppm, preferably about 10 ppm. For example, the first concentration of the biocidal species released into the first water supply upon initial contact at the initial time to (e.g. when the volume of the first water supply that has passed through the disinfection cartridge(s) is less than 10 MT, e.g. less than 5 MT, e.g. less than 1 MT) with the first medium is between 5 ppm and 15 ppm, preferably 8 to 12 ppm, preferably about 10 ppm.

In some embodiments, the first concentration of the biocidal species provides contact disinfection through contact with the first medium. In some embodiments, the first concentration of the biocidal species provides a residual disinfection effect downstream of the water disinfection cartridges due to the (e.g. high) concentration of the biocidal species in the disinfected water supply (e.g. residual biocidal species) which have not reacted with any pathogens. In some embodiments, contact disinfection and a downstream residual disinfection effect occur when the first concentration of biocidal species in the disinfected water supply is greater than 0.3 ppm or greater than 0.5 ppm, e.g. 0.3 ppm to 2 ppm may be a preferred range, or 0.5 to 1.5 ppm may be a preferred range. This means that the disinfected water supply may already have a first concentration that is close to a desired concentration, before passing through the balance tank, with the adjustment effect of the balance tank ensuring that the desired concentration is accurately achieved by the second concentration. As mentioned above, the second concentration of the biocidal species in the balanced water may have a lower tolerance level than the first concentration of the biocidal species in the disinfected water supply.

In some embodiments, the first medium is selected to comprise a wt% of the releasable biocidal species that, upon contact with the first water supply, provides contact disinfection through contact with the first medium, as well as providing a residual disinfection effect e.g. downstream of the water disinfection cartridges. For example, the first medium may comprise between 5 wt% and 90 wt% of the biocidal species, e.g. oxidative halogen, for example oxidative bromine (e.g. Br⁺).

In some embodiments, the first concentration of the biocidal species in the disinfected water supply decreases (e.g. linearly, e.g. non-linearly) with an increasing total volume of the first water supply that has passed through the disinfection unit at a time t > to. In some embodiments, the first concentration of the biocidal species in the disinfected water supply tends to reduce with an increasing total volume of water coming into contact with the first medium, since the initial time to, according to a non-linear release profile. The adjustment effect of the balance tank can counteract such a reduction and ensure that the second concentration is substantially constant across the working lifetime of the disinfection unit. In some embodiments, the second medium comprises between 0 wt% and 20 wt% of the biocidal species at the initial time to, preferably 5 wt% to 15 wt% biocidal species, preferably 0 wt% to 10 wt%, preferably 10 wt% to 20 wt% biocidal species, e.g. oxidative halogen, for example oxidative bromine (e.g. Br⁺). In preferable embodiments, the second medium includes biocidal halogenated (e.g. brominated) polymer resin beads.

In some embodiments, the second medium initially releases a concentration of the biocidal species between 0.1 ppm and 1 ppm at the initial time to, e.g. between 0.2 and 0.8 ppm, e.g. between 0.1 and 0.3 ppm, e.g. about 0.3 ppm, e.g. about 0.5 ppm.

In some embodiments, the percentage by weight (wt%) of the releasable biocidal species included in the second medium varies as the total volume of disinfected water that has come into contact with the second medium increases since the initial time to. In some embodiments, a percentage by weight (wt%) of the releasable biocidal species in the second medium increases when the rate ratio is greater than 1, decreases when the rate ratio is less than 1 , and stays the same when the rate ratio is equal to 1. For example, in periods where the first concentration of the disinfected water supply is greater than the desired second concentration (e.g. about 0.3 to 2 ppm, e.g. about 0.5 to 1 ppm) then the second medium will provide an adjustment effect of net absorption such that the percentage by weight (wt%) of the releasable biocidal species included in the second medium increases, e.g. the amount of the biocidal species that is bound (e.g. non-covalently, e.g. covalently) to the second medium increases. For example, in periods where the first concentration of the disinfected water supply is less than the desired second concentration (e.g. about 0.3 to 2 ppm, e.g. about 0.5 to 1 ppm) then the second medium will provide an adjustment effect of net release such that the percentage by weight (wt%) of the releasable biocidal species included in the second medium decreases, e.g. the amount of biocidal species included in the second medium decreases as more of the biocidal species is released into the disinfected water supply to create a balanced water supply having a second concentration greater than the first concentration.

In some embodiments, the second medium initially reversibly binds with the biocidal species to absorb a concentration of the biocidal species between 1 ppm and 15 ppm at the initial time tO. The adjustment effect at the initial time to is therefore a net absorption to provide a second concentration of the biocidal species in the balanced water supply output from the balance tank which is less than the first concentration of the biocidal species in the disinfected water supply input to the balance tank via the balance tank inlet at the initial time to. It will be appreciated that the water disinfection cartridges include a finite amount (e.g. weight percentage) of the releasable biocidal species, and thus a finite lifetime in which the first concentration is able to provide an efficacious disinfection effect before the first medium is depleted of the biocidal species. The balance tank will be able to adjust a low first concentration to reach a higher second concentration over a certain time period, but only until the second medium also becomes depleted of the biocidal species. There will, therefore, come a point in which the first concentration and/or the second concentration will fall too low to for an efficacious disinfection effect. At this point the disinfection cartridges and/or balance tank will need to be (i) replaced, or at least the first/second medium replaced with another medium including a higher percentage by weight (wt%) of the biocidal species, or (ii) replenished (i.e. without replacement of the first/second medium).

It should be understood that replenishing a disinfection cartridge or the balance tank, within the meaning of the present invention, relates to any suitable method of increasing the percentage by weight (wt%) of the biocidal species included in the first/second medium (i.e. “recharging” the medium). This may be achieved by suitable treatment of the first/second medium, possibly in situ, for example by exposing the medium to a source of free halogen, for example as described in US 2003/0044378, the entire contents of which are incorporated herein by reference. In some examples, the second medium of the balance tank may be replenished by exposing the second medium (with its vacant binding sites) to a high first concentration of the biocidal species from the disinfected water supply, e.g. by passing the first water supply water through at least one disinfection cartridge wherein the first medium comprises a relatively high amount e.g. at least 30 wt%, 35 wt% or 40 wt% of the biocidal species.

In some embodiments, the water disinfection cartridge(s) are configured to be replaced or replenished when the percentage by weight (wt%) of the biocidal species in the first medium falls below 20 wt%. For examples, in some embodiments the disinfection cartridge(s) are configured to be replaced or replenished when the first concentration of the biocidal species in the disinfected water supply falls below 0.5 ppm, e.g. below 0.2 ppm, e.g. below 0.1 ppm.

In some embodiments, the balance tank is configured to be replaced or replenished when the percentage by weight (wt%) of the biocidal species in the second medium falls below 10 wt%, e.g. below 9 wt%, e.g. below 8 wt%, e.g. below 7 wt%, e.g. below 6 wt%, e.g. below 5 wt%. In some embodiments, the balance tank is configured to be replaced or replenished when the second concentration of the biocidal species in the balanced water supply falls below about 0.5 ppm. As mentioned above, it is preferable for the second concentration to be at least 0.5 ppm so as to provide a residual disinfection effect resulting from a residual level of the biocidal species present in the balanced water supply.

The system may include one or more means for monitoring when the disinfection cartridges and/or balance tank are due to be replaced or replenished. For example, a sensor located in the disinfected water supply and/or a sensor located in the balanced water supply may be used to monitor the first concentration and/or the second concentration. For example, the system may comprise a timer that has been programmed based on factors such as an initial weight percentage of the biocidal species in the first/second medium, an expected release profile, and an expected or average flow rate through the system. The timer may be preprogrammed with an expected lifetime or the lifetime may be calculated in situ and updated in response to system variables such as flow rate. The system may include an alert means for indicating when to replace or replenish the water disinfection cartridges and/or the balance tank based on the monitoring means.

In some embodiments, the system comprises: means for monitoring a total volume of the first water supply that has passed through the disinfection unit since an initial time tO; and alert means for indicating when to replace or replenish one or more of the water disinfection cartridges based on the total volume. The inventors have recognised that this provides a particularly simple and effective way of monitoring the working lifetime of the disinfection cartridges without needing a real time clock. As is illustrated by Figure 9b, a given disinfection cartridge may have a characteristic release profile as a function of total volume, which does not change significantly as a result of changes in the flow rate. By monitoring the total volume, it can be predicted quite accurately when the first concentration of the biocidal species in the disinfected water supply is falling below a certain level.

In various embodiments, the system further comprises a controller configured to compare the total volume to an expected disinfection cartridge lifetime. In some examples, the expected disinfection cartridge lifetime is associated with the percentage by weight (wt%) of the biocidal species in the first medium falling below 20 wt%. In some examples, the expected disinfection cartridge lifetime is associated with the first concentration of the biocidal species in the disinfected water supply falling below about 0.5 ppm, e.g. below about 0.3 ppm. The expected disinfection cartridge lifetime may be pre-programmed for a given disinfection cartridge (or for a given disinfection unit) and stored in a memory of the controller. As the second medium is capable of absorbing the biocidal species as well as releasing, the balance tank may not become depleted across the disinfection cartridge lifetime. Thus it is envisaged that the disinfection cartridges will need to be replaced/replenished more frequently than the balance tank. However, it may still be desirable to monitor when the balance tank is due to be replaced or replenished.

In some embodiments, in addition or alternatively, the system comprises: means for monitoring a total volume of the water supply (e.g. disinfected water supply, e.g. combined water supply) that has passed through the balance tank since an initial time tO; and alert means for indicating when to replace or replenish the balance tank based on the total volume. As above, the inventors have recognised that this provides a particularly simple and effective way of monitoring the working lifetime of the balance tank. By monitoring the total volume, it can be predicted quite accurately when the second concentration of the biocidal species in the balanced water supply is falling below a certain level.

In various embodiments, the system further comprises a controller configured to compare the total volume to an expected balance tank lifetime. In some examples, the expected balance tank lifetime is associated with the percentage by weight (wt%) of the biocidal species in the second medium falling below 10 wt%. In some examples, the expected balance tank lifetime is associated with the second concentration of the biocidal species in the balanced water supply falling below about 0.5 ppm, e.g. below about 0.3 ppm. The expected balance tank lifetime may be pre-programmed and stored in a memory of the controller.

In various embodiments, the total volume may be monitored by at least one flow meter.

The embodiments described above are beneficial in terms of their simplicity and ability to finely adjust the first concentration automatically to provide a desired second concentration. However, it will be appreciated that the balance tank will have a finite number of vacant binding sites available such that, should a disinfected water supply with a very high first concentration of biocidal species be passed through the balance tank, it is possible that all vacant binding sites in the second medium will be filled and the rate of absorption of the second medium will be substantially null and no adjustment effect will result. Thus, in various scenarios it may be advantageous to dilute the disinfected water supply upstream of the balance tank to ensure that the balance tank remains functionally active (e.g. including both vacant binding sites and releasable biocidal species) for as long as the disinfection cartridges remain above their replacement/replenishment threshold (e.g. when the first medium comprises less than 20 wt% biocidal species). In some embodiments, the system further comprises a dilution inlet arranged to bring a second water supply to combine with the disinfected water supply downstream of the water disinfection cartridges to produce a combined water supply; wherein the balance tank inlet is arranged to bring the combined water supply to the balance tank. By combining the second water supply with the disinfected water supply it is possible to reduce the first concentration of the biocidal species to a lower level before the combined water supply undergoes the adjustment effect provided by the balance tank

In some embodiments, the second water supply is arranged in parallel with the first water supply passing through the water disinfection cartridges. In some embodiments, the second water supply is split from the first water supply upstream of the water disinfection cartridges such that the second water supply is arranged in parallel with the first water supply when the first water supply is passing through the water disinfection cartridges. In some embodiments, the second water supply may be sourced from an independent water supply to the first water supply.

In some embodiments, the system further comprises a controller and at least one controllable valve; wherein the controller is configured to selectively operate the controllable valves(s) to control the flow of the first and/or second water supplies within the system.

In some embodiments the system further comprises a controller configured to (e.g. actively) control a ratio (e.g. by configuring the controllable valves or otherwise) in which the disinfected water supply and the second water supply are combined in order to achieve a desired third concentration of the biocidal species in the combined water supply (e.g. brought to the balance tank). The ratio may be defined as a volume ratio or a flow rate ratio. By controlling the ratio, the method can react to changes in the first concentration of the biocidal species in the disinfection water supply. In preferred embodiments, the third concentration of the biocidal species in the combined water supply is less than the first concentration of the biocidal species in the disinfected water supply. In other words, a dilution effect is achieved upstream of the balance tank.

In some embodiments, the combined water supply has a third concentration of the biocidal species of between 0.3 ppm and 2 ppm, or between 0.5 ppm and 1.5 ppm. This has been found to provide a residual disinfection effect at least when the biocidal species comprises oxidative halogen, in particular oxidative bromine (e.g. Br+). As discussed above, this residual disinfection effect may be maintained after the combined water supply has passed through the balance tank. The balance tank can act to achieve fine tuning of the third concentration to reach the second concentration of the biocidal species in the balanced water supply output from the balance tank.

Thus the combining of a second water supply with the disinfected water supply may advantageously be used to achieve a desired and/or consistent second concentration of the biocidal species in the balanced water supply (e.g. output to a downstream drinking line) regardless of variations in the first concentration of the biocidal species present in the disinfected water supply before combination with the second water supply. Thus, the dilution effected by combining the disinfected water supply with the second water supply provides a coarse dilution effect of the first concentration of the biocidal species to provide the third concentration of the biocidal species. It will then be appreciated that small variations in the third concentration of the biocidal species may then be (e.g. finely) tuned by the balance tank positioned downstream such that the third concentration of the biocidal species is adjusted to provide the desired second concentration of the biocidal species.

Thus, in some embodiments, the rate ratio of the second medium determines an adjustment effect that the balance tank has on the third concentration of the biocidal species in the combined water supply to achieve a second concentration of the biocidal species in the balanced water supply output from the balance tank. Thus the embodiments described above, in relation to the adjustment effect exerted by the balance tank on the first concentration to provide a desired second concentration, may be similarly applied to the adjustment effect exerted by the balance tank on the third concentration to provide a desired second concentration.

In at least some embodiments, the controller controls the ratio in which the disinfected water supply and the second water supply are combined in order to achieve a desired third concentration of the biocidal species in the combined water supply by: monitoring a total volume of the first water supply that has passed through the water disinfection cartridges since an initial time tO; and setting the ratio in which the disinfected water supply and the second water supply are combined based on the total volume.

In at least some embodiments, the total volume of water may be monitored by at least one flow meter. For example, in embodiments where the first and second water supplies are combined upstream of the water disinfection cartridges (e.g. before the second water supply is split to be arranged in parallel with the first water supply passing through the disinfection cartridges), a flow meter positioned upstream of the disinfection cartridges may be used to measure the total volume of water. In some embodiments, the total volume of water may be monitored by more than one flow meter. For example, in embodiments where the total volume of water is equal to the summation of the volume of the first water supply and the second water supply, a flow meter may be provided in both the first and second water supply lines such that the volume of both the first and second water supplies may be independently measured.

In some embodiments the controller is configured to control the ratio in which the disinfected water supply and the second water supply are combined by controlling the operation of at least one of: a dilution control valve which is arranged to control the amount of water that passes into the second water supply; a disinfection control valve which is arranged to control the amount of water that passes into the first water supply; and/or a flow control valve which is arranged to control the amount of water that passes into each disinfection cartridge. In preferable embodiments, one or more flow control valves are arranged to control the amount of water from the first water supply that passes into each of the water disinfection cartridges (e.g. when n>2).

In some embodiments, the second water supply comprises a substantially zero concentration of the biocidal species when the second water supply is combined with the disinfected water supply.

However, the inventors have further recognised that, in some circumstances, for example, when the rate of release of the biocidal species from the first medium is fast and thus the first concentration of the biocidal species in the disinfected water supply is very high, large volumes of the second water supply may be required to effect the combination ratio to achieve a desired dilution effect. However, when the second water supply comprises a substantially zero concentration of the biocidal species, this results in large volumes of nondisinfected water (and thus potentially unsafe water) constituting a large portion of the combined water supply.

To address this issue, the inventors have appreciated that in some embodiments it may be desirable for the second water supply to also be disinfected through contact with a medium similar to the first medium comprising the releasable biocidal species.

Thus, in some embodiments, the second water supply is arranged to pass through a number n (n>1) of dilution line disinfection cartridges, wherein each dilution line disinfection cartridge comprises a third (e.g. polymeric) medium including the releasable biocidal (e.g. halogen) species that is released into water coming into contact with the medium, to produce a disinfected dilution water supply having a fourth concentration of the biocidal (e.g. halogen) species; wherein it is the disinfected dilution water supply that is combined with the disinfected water supply to produce the combined water supply (the combined water supply e.g. having the third concentration of the biocidal (e.g. halogen) species that is less than the first concentration of biocidal (e.g. halogen) species in the disinfected water supply). This means that the entirety of the combined water supply has been in contact with a medium including the releasable biocidal (e.g. halogen) species before being input to the balance tank.

In some embodiments, the third (e.g. polymeric) medium comprises between 1 wt% and 20 wt% of the biocidal species at the initial time to, preferably 5 wt% to 20 wt% biocidal species, preferably 10 wt% to 20 wt%, preferably 15 wt% to 20 wt% biocidal species. In various embodiments, the biocidal species released by the third medium comprises oxidative halogen, for example oxidative bromine (e.g. Br⁺). In preferable embodiments, the third medium includes biocidal halogenated (e.g. brominated) polymer resin beads.

It will be appreciated from the discussion above that various aspects and embodiments of the present invention may find particular use in treating and disinfecting water for animal consumption. In particular, it has been found that releasing a biocidal species comprising oxidative bromine (e.g. Br⁺) has the dual effect of contact disinfection and an ongoing disinfection effect due to an amount of residual bromine in the water following treatment, which can prevent biofilm build-up in a downstream drinking water distribution system for animal consumption.

In at least some embodiments, the system is an animal drinking water treatment and distribution system, the system further comprising: the balanced water supply being arranged to pass from the balance tank to a drinking water distribution system for animal consumption, e.g. a drinking water distribution system in a farm. The farm may be a livestock or poultry farm. Of course the balanced water supply may be passed directly or indirectly from the balance tank to a drinking water distribution system. For example, the disinfected water supply may optionally be dosed with one or more additives before reaching the drinking water distribution system. Typical additives include flavoured gelatin mixes, powdered drink mixes, vitamins, electrolytes, sugar water, stabilizers, antibiotics, etc. Such additives can act as a food source for biofilms in the drinking water distribution system, but biofilm formation can be reduced or prevented at least in those embodiments wherein the second concentration of the biocidal species in the balanced water supply is selected to provide a residual disinfection effect resulting from a residual level of the biocidal species present in the diluted water supply, as has already been described above.

There will now be described some further features that may be combined with any of the embodiments described above.

In some embodiments, a plurality (n>2) of the water disinfection cartridges are in a parallel arrangement including one or more controllable valves in the first water supply, each controllable valve arranged in series with an associated water disinfection cartridge of the plurality of water disinfection cartridges. In such embodiments, the method may further comprise measuring one or more flow parameters (e.g. actual flow rate, average flow rate, total volume of water) relating to the first water supply and controlling one or more controllable valves to open or close in response to the one or more flow parameters.

In some embodiments, opening or closing one or more controllable valves provides a control of the flow of water to each of the associated disinfection cartridges such that the amount of the biocidal species that is released as water flows through the parallel arrangement of the disinfection cartridges may be adjusted.

Furthermore, this approach can be extended to any number of controllable valves. In at least some embodiments, the plurality of n disinfection cartridges are in a parallel arrangement and a number n of controllable valves each arranged in series with one of the n disinfection cartridges (i.e. the same number of disinfection cartridges and controllable valves), wherein the method comprises selectively operating a number m of the n controllable valves to close a parallel flow of water to m disinfection cartridges in the parallel arrangement, wherein m < n, depending on the total volume of water since an initial time to. The m disinfection cartridges can be recharged or replaced while shut off from the water flow through the parallel arrangement. The initial time to may be reset when one or more of the disinfection cartridges are recharged or replaced.

In some embodiments, the first concentration of the biocidal species in the disinfected water supply tends to reduce with an increasing total volume of water coming into contact with the first medium since the initial time to. In some embodiments, the water disinfection cartridges have a non-linear release profile in terms of the rate of release of the biocidal species from the medium. Thus, in some embodiments there may be a defined reference profile of the first concentration as a function of the total volume for each water disinfection cartridge. This may be used, as described above, when monitoring the total volume so as to determine when to replace or replenish the disinfection cartridges.

In various embodiments described above, a controllable valve may be selected to be any suitable type. When the method involves the operation of a valve it means that the valve is opened or closed or the flow rate through the valve is otherwise adjusted. In some examples the one or more controllable valves are fixed on/off valves. In some examples the one or more controllable valves are regulating valves. Of course the methods disclosed herein may include operation of a mixture of different valve types.

Some embodiments relate to use of a system as described herein to treat water for animal consumption.

According to another aspect of the present invention there is provided a method of disinfecting water for animal consumption, the method comprising: arranging a first water supply to pass through a water treatment system, the system comprising: a disinfection inlet arranged to bring a first water supply to a disinfection unit; the disinfection unit comprising a number n (n>1) of water disinfection cartridges, wherein each water disinfection cartridge comprises a first (e.g. polymeric) medium including a releasable biocidal (e.g. halogen) species that is released into the first water supply coming into contact with the first (e.g. polymeric) medium to provide a disinfected water supply, wherein the disinfected water supply has a first concentration of the biocidal (e.g. halogen) species; a balance tank inlet arranged to bring the disinfected water supply to a balance tank; the balance tank comprising a second (e.g. polymeric) medium including: the releasable biocidal (e.g. halogen) species, arranged to be available to be released at a release rate into the disinfected water supply coming into contact with the second (e.g. polymeric) medium; and vacant binding sites, arranged to reversibly bind at an absorption rate with the biocidal (e.g. halogen) species in the disinfected water supply coming into contact with the second (e.g. polymeric) medium; wherein a ratio of the absorption rate to the release rate defines a rate ratio of the second (e.g. polymeric) medium; and wherein the rate ratio of the second (e.g. polymeric) medium determines an adjustment effect that the balance tank has on the first concentration of biocidal (e.g. halogen) species in the disinfected water supply to achieve a second concentration of the biocidal (e.g. halogen) species in a balanced water supply output from the balance tank: the method comprising (e.g. at a time t > toy. arranging the first water supply to pass through the disinfection cartridges to provide the disinfection water supply; and arranging the disinfection water supply to pass through the balance tank to provide the balanced water supply.

In some embodiments the method comprises carrying out these steps at a time t > to, e.g. when the system has already been operating for a period so that the second (e.g. polymeric) medium includes a certain weight percentage of the releasable biocidal (e.g. halogen) species at least through absorption.

In some embodiments the method further comprises measuring one or more parameters relating to the flow of water through the water inlet and controlling the one or more controllable valves to open or close in response to the one or more parameters so as to control the flow of water to each associated disinfection cartridge and thereby adjust the first concentration of the biocidal species in the disinfected water supply.

As already disclosed, the one or more parameters relating to the flow of water through the disinfection inlet may comprise one or more of: an actual flow rate, an average flow rate, a total volume of water that has flowed through the disinfection inlet since an initial time to.

In at least some embodiments, the method may further comprise: arranging the balanced water supply to be delivered for animal consumption, e.g. to pass from the balance tank to a drinking water distribution system in a farm. The farm may be a livestock or poultry farm.

According to another aspect of the present invention there is provided a method of refurbishing the system according to any embodiment disclosed herein, the method comprising: monitoring the total volume to have passed through the disinfection unit since an initial time tO; comparing the total volume to an expected disinfection cartridge lifetime; and replacing or recharging the first (e.g. polymeric) medium at the end of a disinfection cartridge lifetime. As already disclosed above, in some embodiments the expected disinfection cartridge lifetime is associated with the percentage by weight (wt%) of the biocidal species in the first medium falling below about 20 wt%. In some embodiments the expected disinfection cartridge lifetime is associated with the first concentration of the biocidal species in the disinfected water supply falling below about 0.5 ppm, e.g. below about 0.3 ppm.

According to another aspect of the present invention there is provided a method of refurbishing the system according to any embodiment disclosed herein, the method comprising: monitoring the total volume of the water supply (e.g. disinfected water supply, e.g. combined water supply) to have passed through the balance tank since an initial time tO; comparing the total volume to an expected balance tank lifetime; and replacing or recharging the second (e.g. polymeric) medium at the end of a balance tank lifetime.

As already disclosed above, in some embodiments the expected balance tank lifetime is associated with the percentage by weight (wt%) of the biocidal species in the second medium falling below about 10 wt%. In some embodiments the expected balance tank lifetime is associated with the second concentration of the biocidal species in the balanced water supply falling below about 0.5 ppm, e.g. below about 0.3 ppm.

Such refurbishing methods may be used alone or in combination with one another.

In at least some embodiments, the methods disclosed herein are a computer-implemented method. The methods disclosed herein may be carried out by a processor.

The methods disclosed herein may be implemented at least partially using software, e.g. computer programs. It will thus be seen that when viewed from further embodiments the present invention provides computer software specifically adapted to carry out the methods herein described when installed on a data processor, a computer program element comprising computer software code portions for performing the methods herein described when the program element is run on a data processor, and a computer program comprising code adapted to perform all the steps of a method or of the methods herein described when the program is run on a data processing system. Thus the invention extends to a computer readable storage medium storing computer software code which when executed on a data processing system performs the methods described herein. The present invention also extends to a computer software carrier comprising such software arranged to carry out the steps of the methods disclosed herein. Such a computer software carrier could be a physical storage medium such as a ROM chip, CD ROM, RAM, flash memory, or disk, or could be a signal such as an electronic signal over wires, an optical signal or a radio signal such as to a satellite or the like.

It will further be appreciated that not all steps of the methods disclosed herein need be carried out by computer software and thus from a further broad embodiment the present invention provides computer software and such software installed on a computer software carrier for carrying out at least one of the steps of the methods set out herein.

Some embodiments of the present invention may accordingly suitably be embodied as a computer program product for use with a computer system. Such an implementation may comprise a series of computer readable instructions either fixed on a tangible, non-transitory medium, such as a computer readable storage medium, for example, diskette, CD ROM, ROM, RAM, flash memory, or hard disk. It could also comprise a series of computer readable instructions transmittable to a computer system, via a modem or other interface device, over either a tangible medium, including but not limited to optical or analogue communications lines, or intangibly using wireless techniques, including but not limited to microwave, infrared or other transmission techniques. The series of computer readable instructions embodies all or part of the functionality previously described herein.

Those skilled in the art will appreciate that such computer readable instructions can be written in a number of programming languages for use with many computer architectures or operating systems. Further, such instructions may be stored using any memory technology, present or future, including but not limited to, semiconductor, magnetic, or optical, or transmitted using any communications technology, present or future, including but not limited to optical, infrared, or microwave. It is contemplated that such a computer program product may be distributed as a removable medium with accompanying printed or electronic documentation, for example, shrink wrapped software, pre-loaded with a computer system, for example, on a system ROM or fixed disk, or distributed from a server or electronic bulletin board over a network, for example, the Internet or World Wide Web.

As discussed above, the present invention relates to disinfection cartridges which comprise a (e.g. polymeric) medium including a releasable biocidal (e.g. halogen) species that is released into water coming into contact with the medium as water flows through the cartridge, thus the overall contact time (represented by total volume) and/or instantaneous contact time (represented by flow rate) can affect the amount of biocidal (e.g. halogen) species that is released. In at least some embodiments, the amount of the biocidal (e.g. halogen) species that is released as water flows through the cartridge tends to reduce with an increasing total volume of water coming into contact with the medium. This results in a declining concentration per unit volume of the biocidal (e.g. halogen) species.

In some embodiments, the first (and/or second and/or third) medium is a polymeric medium, e.g. comprising a cross-linked polymer (e.g. polystyrene) resin. In some embodiments, the polymeric medium includes a nitrogen-based functional group arranged to form a N-halogen covalent bond. Preferably the polymeric medium is a N-halamine polymer e.g. comprising N- halamine polymer to provide the releasable biocidal species as a halogen species, e.g. chlorine or bromine. A N-halamine polymer has a halogen species covalently bound to an amine moiety in a polymer (i.e. a N-halamine polymer is not a halogenated ion exchange resin wherein the interaction between the polymeric resin and the halogen is ionic).

In some embodiments, preferably the first/second/third medium is a polymeric medium comprising hydantoin, e.g. poly(styrenehydantoin). In some embodiments, the (e.g. first, e.g. second, e.g. third) medium including a releasable biocidal halogen species (e.g. chlorine or bromine) is provided by a halogenated hydantoin. For example, the first/second/third medium including the releasable biocidal species is N-halogenated poly(styrenehydantoin), e.g. poly[1 ,3-dichloro-5-methyl-5-(4'-vinylphenyl)hydantoin] and poly[1 ,3-dibromo-5-methyl-5-(4'- vinylphenyl)hydantoin].

In some embodiments, the (e.g. first, e.g. second, e.g. third) medium is provided as a (e.g. plurality of) polymeric (e.g. resin) bead(s).

In at least some embodiments, the biocidal species released by each disinfection cartridge comprises or consists of an oxidative halogen, for example oxidative chlorine or oxidative bromine (e.g. in the form of Br⁺ or covalently bound oxidative bromine in Br2). In at least some embodiments, each disinfection cartridge comprises a medium including biocidal halogenated (e.g. brominated, e.g. chlorinated) polymer resin beads. In one or more examples, the biocidal species comprises between 5 wt% and 90 wt% oxidative halogen, preferably 5 wt% to 50 wt% oxidative halogen, preferably 20-45 wt% oxidative halogen, preferably 30-35 wt% oxidative halogen, preferably 30-40 wt% oxidative halogen, for example oxidative bromine (Br⁺ based or Br2 based). Suitable disinfection cartridges are described in US 2003/0044378, US 2004/0086480 and US 2012/0035284, the entire contents of which are incorporated herein by reference. In some embodiments, the disinfection cartridges each comprise a flow-through column of the (e.g. polymeric) medium including a releasable biocidal (e.g. halogen) species. In some embodiments, the disinfection cartridges each comprise a column bed filter comprising a polymer medium, e.g. polymer resin beads, e.g. biocidal halogenated polymer, e.g. biocidal brominated polymer resin beads, e.g. N-halamine biocidal polymer resin beads, e.g. halogenated (e.g. brominated) polystyrenehydantoin resin beads, e.g. monobrominated polystyrenehydantoin resin beads, e.g. methylated polystyrene hydantoin resin beads.

In some embodiments, the medium is arranged to release a biocidal species comprising an oxidative halogen, such as oxidative chlorine, preferably such as oxidative bromine. As water passes over the medium (e.g. halogenated resin beads) the (e.g. covalently bound) biocidal species (e.g. oxidative bromine) is released into the water, preferably at a controlled rate.

In some embodiments, the biocidal species released by the medium is a halogen, e.g. oxidative chlorine, e.g. oxidative bromine. In preferred embodiments the biocidal species is oxidative bromine (Br⁺). It will be appreciated that at a pH of 6.5-8.5 corresponding to regular drinking water, the oxidative bromine will form hypobromous acid (HOBr) which is a disinfectant species. Hypobromous acid is readily formed in water by the disproportionation of elemental bromine (Br2) with the equilibrium lying to the right and favouring the formation of HOBr at a pH between 6.5 and 8.5:

Br₂ + 2H₂O <-> HOBr + H₃O⁺ + Br“

Hypobromous acid is further in equilibrium with hypobromite (OBr) in a pH-dependent manner in the drinking water:

H0Br + H₂0 «-> H₃O⁺ + OBr-

Hypobromous acid displays antimicrobial activity that is superior to the analogous species for chlorine (hypochlorous acid). Hypobromous acid readily reacts with ammonia and amines to produce bromoamines that are also effective biocide species. These biocidal species, which may be referred to as “residual bromine”, remain in the water after it has passed out from a disinfection cartridge and hence can provide an antimicrobial effect in a water delivery system downstream of the disinfection cartridges.

In embodiments where the medium is a halogenated (e.g. brominated) polystyrenehydantoin resin particle, halogen species (e.g. bromine, e.g. chlorine) may be chemically bound (e.g. covalently bound) to the amide nitrogen (1) and/or the imide nitrogen (2). When in contact with water, the halogen dissociates (as shown below) to produce a hypohalous acid (e.g. hypobromous acid, e.g. hypochlorous acid).

It will be appreciated that an amide-halogen bond is stronger than an imide-halogen (at least in part due to the increased electron density in the amide-halogen bond due to fewer adjacent electron withdrawing groups), and thus the dissociation constant for the release of halogen (e.g. bromine) is greater (thus yielding a greater quantity of hypohalous acid) for the imide-halogen bound species.

As already presented above, a polymeric medium including a releasable biocidal halogen species should be understood as a polymeric medium including an amide-halogen/imide- halogen covalent bond of the type that can dissociate in the presence of water to release the halogen species.

It will be appreciated that the strength of the amide-halogen/imide-halogen bond is highly dependent on the identity of the halogen species. For example, as a bromine atom is larger than a chlorine atom, the N-Br covalent bond is longer and weaker than an N-CI covalent bond. As such, the N-Br bond may be broken more easily than the N-CI bond and bromine is realised more readily from the brominated resin bead than chlorine is by way of contrast. As such, a resin bead comprising N-CI bonds may produce a lower concentration of residual chlorine than a N-Br bond which may in turn effect the effectiveness of the biocidal species.

Similarly, iodine is larger than bromine and thus any N-l bond (if formed) would be in turn, longer and weaker than the N-Br bond such that any N-l bond is more labile and iodine is released more readily than bromine. This may result in iodine concentrations that are too high to be safe. As such, it will be appreciated that the choice of halogen species bound to a polymeric medium via an amine or imine moiety results in different release profiles and thus antimicrobial efficacy. The inventors suggest that any N-l bond to an amine or imine moiety may in fact be too weak and unstable for iodine to be considered covalently bound to the functional group of the polymeric medium, in particular for the example of a hydantoin functional group.

In preferred embodiments of the present invention, a brominated polymer medium is used as presenting a good compromise between bond lability, efficacy, safety and polymeric medium lifetime (e.g. how long the resin remains effectively charged, e.g. how long before an efficacious amount of halogen species is no longer released).

Furthermore, the choice of halogen species may affect the disinfection properties of the water disinfection cartridges. For example, the disinfection properties of bromine and chlorine have been previous compared and it has been determined that bromine is more effective in disinfecting bacteria, viruses and protozoan parasites at higher pH levels (e.g. pH 9 or 9.5) and in the presence of ammonia. Bromine also provides greater protection across a wider pH range than chlorine and has a greater effectiveness for poor quality of water. Reference is made to “Alternative drinking water disinfectants: bromine”, WHO 2018, ISBN 978-92-4- 151369-2, the contents of which are hereby incorporated by reference.

In some embodiments, the (e.g. polymeric) first/second/third medium (e.g. resin beads), when installed in the disinfection cartridges, comprises between 5 wt% and 90 wt% oxidative halogen (e.g. bromine, e.g. chlorine), e.g. 5 wt% and 50 wt%, e.g. 10 wt% and 80 wt%, e.g. 10 wt% and 60 wt%, e.g. 10 wt% and 45 wt%, e.g. 10 wt% and 40 wt%, e.g. 10 wt% and 20 wt%, e.g. 12 wt% and 18 wt% e.g. at least 15 wt%, e.g. 15 wt% and 45 wt%, e.g. 15 wt% and 40 wt%, e.g. 15 wt% and 36 wt%, e.g. at least 20 wt%, e.g. 20 wt% and 45 wt%, e.g. 20 wt% and 35 wt%, e.g. 22 wt% and 40 wt%, e.g. 22 wt% and 32 wt%. In preferred embodiments the biocidal species is selected to be oxidative bromine.

In a first set of examples, the biocidal species is Br⁺-based oxidative bromine. In such examples, the first/second/third medium (e.g. resin beads), when installed in a disinfection cartridge, comprises between 5 wt% and 60 wt% of the biocidal species, e.g. 30 to 60 wt% of the biocidal species, e.g. 40 to 60 wt% of the biocidal species, e.g. 50 to 60 wt% of the biocidal species, e.g. 30 to 40 wt% of the biocidal species, e.g. 30 to 50 wt% of the biocidal species.

In a second set of examples, the biocidal species is Br2-based oxidative bromine. In such examples, the medium (e.g. resin beads), when installed in a disinfection cartridge, comprises between 40 wt% and 90 wt% of the biocidal species, e.g. 50 wt% to 80 wt% of the biocidal species, e.g. 60 wt% to 80 wt% of the biocidal species.

In one or more examples, the medium (e.g. resin beads) has a particle (e.g. bead) size of between 100 pm and 5000 pm, e.g. between 100 pm and 1500 pm, e.g. between 200 pm and 1500 pm, e.g. between 300 pm and 1000 pm.

In preferred embodiments, the disinfection cartridges are selected to be cartridges comprising a medium including releasable oxidative bromine, such as HaloPure™ cartridges containing brominated polystyrene hydantoin beads.

Detailed Description

Some embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a water treatment system according to an embodiment of the present invention, in a parallel configuration;

Figure 2 shows a water treatment system according to another embodiment of the present invention, in a linear configuration;

Figure 3 shows an embodiment of the Disinfection System seen in Figures 1 and 2, including external dilution control;

Figure 4 shows an example configuration of the Disinfection unit which forms part of the Disinfection System shown in Figure 2;

Figure 5 shows an example configuration of the Dosing System seen in Figures 1 and 2 in more detail;

Figure 6 shows an example configuration of the Pre-Treatment unit seen in Figures 1 and 2 in more detail;

Figure 7 shows a detailed embodiment of a water treatment system of the type shown in Figure 1 , using an external dilution approach;

Figure 8 shows a block diagram of an apparatus for controlling the water treatment system of Figure 7;

Figure 9a shows a schematic representation of the concentration of biocidal species bound within a disinfection cartridge medium as a function of total water volume that has passed through the cartridge;

Figure 9b shows a typical bromine release profile of a HaloPure™ disinfection cartridge in terms of biocide concentration as a function of the total water volume;

Figure 10 shows another embodiment of the Disinfection System seen in Figures 1 and 2, including internal dilution control; Figure 11 shows an example configuration of the Disinfection unit which forms part of the Disinfection System shown in Figure 10;

Figure 12 shows another detailed embodiment of a water treatment system of the type shown in Figure 1, using an internal dilution approach;

Figure 13 shows a block diagram of an apparatus for controlling the water treatment system of Figure 12;

Figure 14 shows another embodiment of the Disinfection System seen in Figures 1 and 2, including dilution control and balancing;

Figures 15a-15c illustrate some examples of the biocide concentration and bound concentration interact in a balance tank;

Figure 16 shows a schematic representation of the bromine concentration as a function of the total water volume for a typical disinfection unit and balance tank as seen in Figure 14;

Figures 17a-17d show a schematic representation of the concentration of biocidal species bound within a disinfection cartridge medium and a balance tank medium as a function of total water volume that has passed through the disinfection system of Figure 14; and

Figure 18 shows another detailed embodiment of a water treatment system of the type shown in Figure 1 , using an external dilution approach in combination with a balance tank.

As can be seen from Figure 1 and Figure 2, the water treatment system 100, 102 is formed from a plurality of modular units (Pre-Treatment unit 110, Disinfection System unit 200, 202 and Dosing System unit 300) which may be arranged in any suitable or desirable configuration. Figure 1 shows an embodiment wherein the Disinfection System 200, 202 and an optional Dosing System 300 are arranged in parallel. Figure 2 shows an embodiment wherein the Disinfection System 200, 202 and an optional Dosing System 300 are arranged in series.

As shown in Figure 1 , raw (e.g. untreated) water to be disinfected enters the system 100 through a main line 105 which is fluidly connected to an optional Pre-Treatment unit 110. The pre-treated water leaves the Pre-Treatment unit 110 through a water inlet line 115 which splits, at junction 120, into a water inlet line 130 for the Disinfection System 200, 202 and a dosing inlet line 140. The water inlet line 130 brings a first water supply to the Disinfection System 200, 202. A flow meter 125 is arranged in the water inlet line 130 downstream of the junction 120. The Disinfection System 200, 202 outputs clean (e.g. disinfected) drinking water to a drinking line 135 e.g. to be consumed by poultry 150 or other animals. The dosing inlet line 140 is connected to the same water inlet line 115 as the disinfection system 200 to provide a parallel water input to the (optional) Dosing System 300. The Dosing System 300 outputs water comprising an additive to another feeding line 145 to be consumed by the poultry 150 or other animals.

The system 102 shown in Figure 2 is similar to system 100 shown in Figure 1 in that raw water enters the (optional) Pre-Treatment unit 110 through a main line 105 and is output from the Pre-Treatment unit 110 through a water inlet line 115 which has a flow meter 125 positioned along its length. The difference between the system 102 shown in Figure 2 and the system 100 shown in Figure 1 is that the water inlet line 115 brings a first water supply to the Disinfection System 200, 202, i.e. the water inlet line 115 does not split upstream of the Disinfection System 200, 202. The Disinfection System 200, 202 outputs clean (e.g. disinfected) drinking water to a clean water line 160 which splits downstream, at a junction 122, into a clean water line 132 and a dosing inlet line 142. The clean water pipeline 132 provides clean (e.g. disinfected) drinking water to drinking line 135 to be consumed by the poultry 150 (or other animals). The dosing inlet line 142 provides a fluid input to the (optional) Dosing System 300. The Dosing System 300 outputs water comprising an additive to feeding line 145 to be consumed by poultry 150 (or other animals).

Figures 3 to 6 show embodiments of the modular components of the units shown in Figures 1 and 2.

Figure 3 shows an example arrangement of the Disinfection System 200 used for treating water for animal consumption. As described above, a first water supply is input to the Disinfection System 200 through a water inlet line 130 (or 115) which splits, at a dilution line input junction 210, into a first water supply for a disinfection inlet 220 to a Disinfection Unit 400 and a second water supply carried by a dilution line 215. The Disinfection Unit 400 comprises a number n (n>1) of water disinfection cartridges 450n. A biocidal species (“biocide”) is released into the first water supply flowing through the Disinfection Unit 400 before it reaches the disinfection outlet 230. The dilution line 215 provides a bypass path for the second water supply which outputs at a dilution output junction 240 downstream of the disinfection outlet 230. The function of the dilution line 215 will be described in more detail below.

A flow meter (or other flow monitoring device) 225 is arranged at the disinfection inlet 220, downstream of the junction 210, to measure one or more parameters relating to the flow of water into the Disinfection Unit 400. A dilution control valve 250 is located in the dilution line 215. Although only one dilution line 215 is shown in Figure 3, it will be appreciated that alternative embodiments of the Disinfection System 200 may include a plurality of dilution lines 215, one or more of the dilution lines 215 including a dilution control valve 250. This will be described further in relation to Figure 7. For example, multiple dilution lines 215 having the same or different flow capacities may be arranged in parallel. In embodiments wherein there is only one dilution line 215, as seen in Figure 3, the dilution control valve 250 is preferably a regulating valve. In embodiments comprising a plurality of dilution lines 215, it is preferable that at least one of the dilution control valves 250 is a regulating valve but some of the dilution control valves 250 may be on/off valves.

The Disinfection unit 400 outputs clean (e.g. disinfected) drinking water comprising residual biocidal species via the disinfection outlet 230, which is then directed through a dilution output junction 240 to an output line 260 which provides drinking water to the drinking line 135 to be consumed by poultry 150 (or other animals). The line break shown in the path between the dilution output junction 240 and drinking line 135 illustrates that the clean water may pass through other modules or systems before its point of consumption at the drinking line 135.

In some embodiments the dilution line(s) 215 and the disinfection outlet 230 from the Disinfection unit 400 are fluidly combined at a simple junction 240 as seen in Figure 3. Alternatively, in some embodiments, the junction 240 may comprise a balance tank 1000 (as seen in Figure 14) providing a holding body for the first and second water supplies from the two lines 215, 230 to adequately mix before being passed downstream to the drinking line 135. This will be described further in relation to Figure 7.

Operation of the Disinfection System 200 will be described later below.

Figure 4 shows an example Disinfection unit 400 arrangement comprising two disinfection cartridges 450 arranged in parallel. Although this example depicts two disinfection cartridges, alternative embodiments may include any number of treatment cartridges e.g. six cartridges.

The first water supply from the disinfection inlet 220 can be directed, at a first bypass junction 410, into either a disinfection line 415 (when a disinfection control valve 425 is open) or a bypass line 420 (when a bypass valve 490 is open). The bypass line 420 provides a backup path which outputs at junction 470 e.g. in the event that the disinfection cartridges 450 are unavailable (for example, during cartridge replenishment or replacement). The bypass valve 490 is selectively opened (and the disinfection control valve 425 may be selectively closed) when it is desired to use the bypass line 420.

The first water supply from the disinfection inlet 220 flows into the parallel arrangement of disinfection cartridges 450 by splitting, at a branch junction 430, to provide separate flow paths to the plurality of treatment cartridges 450 arranged in parallel, via the parallel branch lines 440.

As mentioned above, the disinfection control valve 425 is open when the Disinfection unit 400 is operating in a disinfection mode (rather than a bypass mode). An additional exhaust valve 495 is optionally disposed in the disinfection line 415, downstream of the bypass junction 410 and upstream of the branch junction 430. The exhaust valve 495 may be operated to exhaust some of the water supply to a waste output line 500, e.g. in the event that one or more of the cartridges 450 is blocked. In some embodiments, the disinfection control valve 425 is an on/off valve. In some embodiments, the disinfection control valve 425 is a regulating valve used to control the flow of the first water supply through the Disinfection unit 400. This will be described in more detail with reference to Figures 7 and 8.

Each branch line 440 has positioned along its length a cartridge control valve 445 e.g. disposed between an associated disinfection cartridge 450 and the branch junction 430. The fluid outputs from the treatment cartridges 450 converge at another junction 460. The resultant disinfection outlet line 465 is in fluid communication with disinfection outlet 230 via a second bypass junction 470. An optional disinfection outlet valve 480 is disposed in the disinfection outlet 230.

Operation of the Disinfection Unit 400 will be described later below with reference to various Examples.

Figure 5 shows an example arrangement of the optional Dosing System 300. As described above, water is input to the Dosing System 300 via dosing inlet line 140 that runs parallel to the Disinfection System 200 (Figure 1), or a dosing inlet line 142 split off downstream of the Disinfection System 200 (Figure 2). In both cases, within the Dosing System 300 the dosing inlet line 140, 142 splits, at a bypass junction 310, into pipeline bypass line 315 and a dosing line 320. The bypass line 315 provides an alternative flow path which connects to another bypass junction 350. A bypass valve 340 is located in the bypass line 315. The bypass valve 340 may be manually operated to allow water to bypass the water treatment filter 330, e.g. in the event of a blockage or filter replacement event.

In this embodiment, the dosing line 320 passes through a water treatment filter 330, such as a granular activated carbon (GAC) filter. The input to the filter 330 is controlled by an automatic valve 325. The water treatment filter 330 outputs filtered water via a line 360 to the bypass junction 350. At any point downstream of the junction 350, a dosing inlet 370 is provided to selectively add a dose of one or more additives such as vitamins, medicines, vaccines etc., into the fluid stream before being directed to the feeding line 145 to be consumed by poultry 150 (or other animals). The line break shown in the path between the dosing inlet 370 and the feeding line 145 illustrates that the dosed water may pass through other modules or systems before the point of consumption at the feeding line 145.

In the embodiment illustrated in Figure 5, the water treatment filter 330 is useful for removing any unwanted contaminants in the water provided by the dosing water inlet line 140, 142. When the dosing inlet line 142 is connected downstream of the diluted water outlet 160 of the Disinfection System 200, as seen in Figure 2, the water treatment filter 330 may remove at least some of the biocidal species prior to dosing. However, it will be appreciated that such arrangements involve unnecessary waste and therefore a parallel arrangement, as seen in Figure 1, may be preferred. In these embodiments the water treatment filter 330 does not need to remove the biocidal species so a less effective filter may be employed, or the water treatment filter 330 and its bypass line 315 may even be omitted entirely.

Figure 6 shows an example arrangement of the optional Pre-Treatment unit 110. As described above, raw (i.e. potentially contaminated) water is input to the Pre-treatment unit 110 via a main line 105 which splits, at a bypass junction 510, into a bypass line 515 and a pre-treatment filter line 520. The bypass line 515 provides an alternative flow path which is connected to another bypass junction 550. A bypass valve 540 is located in the bypass line 515. The bypass valve 540 may be manually operated to allow water to bypass the pretreatment filter 530, e.g. in the event of a blockage or filter replacement event.

The pre-treatment filter line 520 provides the fluid input for a pre-treatment filter 530 such as a sand filter. The input to the pre-treatment filter 530 is controlled by an automatic valve 525. The filter 530 outputs pre-treated water via an output line 560 such that the water is directed through the bypass junction 550 into the water inlet line 115 connected to the downstream Disinfection System 200. Figure 7 shows a preferred embodiment with a more detailed view of the Disinfection System 200, wherein the disinfection unit 400 includes six treatment cartridges 450a to 450f arranged in parallel between a disinfection inlet 220 and a disinfection outlet 230. The embodiment shown in Figure 7 further includes two dilution lines 215a and 215b originating from two independent junctions 210a and 210b disposed in the inlet line 130. The dilution lines 215a, 215b include independently operable dilution control valves 250a, 250b.

In this embodiment there are six controllable valves 445a to 445f arranged in the flow of water from the disinfection inlet 220, each cartridge control valve 445n arranged in series with an associated disinfection cartridge 450n in the disinfection unit 400. Input flow junctions 430a to 430f, and output flow junctions 460a to 460d, create a parallel arrangement with each disinfection cartridge 450n and its associated cartridge control valve 445n arranged in a respective parallel flow branch.

It can be seen from Figure 7 that the water inlet line 130 is split at the junctions 210a and 210b such that the disinfection inlet 220 brings a first water supply to the disinfection unit 400 and a second water supply is carried by the dilution lines 215a, 215b. The two independent water supplies are combined downstream of the disinfection unit 400, at a junction 240 (shown here as a tank). The concentration of biocidal species (“biocide”) in water leaving the junction 240 can therefore be adjusted by operating the dilution control valves 250a, 250b, as will be described further below.

Figure 8 shows a block diagram of an exemplary apparatus used to control the disinfection system 200 as shown in Figures 1-4 and 7. The system 100, 102 may be operated in accordance with a series of pre-programmed instructions stored in the memory of a controller 700. The controller 700 executes the operations by communicating with one or more modules in the system 100, 102, where the communication may be either wired or wireless (e.g. via a network). In some embodiments the operations may be carried out at a predetermined frequency (e.g. a pre-set time interval, e.g. every five minutes) or in response to sensor data received by the controller 700, such as data communicated to the controller 700 from flow meters 125 and 225 or other sensors 720 such as a sensor used to detect the concentration of biocidal species in the water e.g. at the disinfection outlet 230 or in the output line 260. Alternatively, the system may perform operations in response to a user instruction, input through a user interface. In preferred embodiments, the system is operated in accordance with the pre-programmed schedule of operations stored in the memory of the controller 700. However, upon receipt of a user input, the controller 700 may override the pre-determined schedule such that the user input operation is performed. This may, for example, allow a user to initiate a specific operation (e.g. activation of the Dosing System 300) at times other than when these operations are automatically scheduled to be performed.

In the embodiment shown in Figure 8, the controller 700 is in communication with all modular units described above i.e., Pre-Treatment unit 110, Disinfection System 200 and Dosing System 300. However, it will be appreciated that each modular unit may alternatively be controlled by independent controllers such that the controller 700 is only in communication with certain controllable components (e.g. cartridge control valves 445a-445f and dilution control valves 250a, 250b) of the Disinfection System 200.

Once the controller 700 determines the operation to be performed by the system 100,102, the controller 700 executes the operation by sending a control signal (e.g. an electrical signal) to the plurality of valves within the system 100, 102 which are used to control the flow of water through the system. Optionally a water input pump 740 is used to control the flow rate and pressure of the raw water entering the system 100, 102. For on/off valves (which can be selected to be any suitable or desirable valve, e.g. valves 425, 480, 445a-445f, 340 and 540) the controller 700 sends a signal that results in the valve being configured to be either open or closed. For regulating valves (e.g. optionally control valves 425 and 250a, 250b) the controller 700 sends an electrical signal, the amplitude of which sets the degree to which the valve is opened, e.g. at maximum amplitude the regulating valve may be 100% open (or closed) and at a quarter amplitude the regulating valve may be 25% open (or closed). The electrical input received by the automatic valves 325 and 525 from the controller 700 configures the valves to be operate in one of three possible modes: filter mode, backwash mode, and filter wash mode.

The controller 700 may also input data relating to the operational conditions of the system to user display 730. For example, the concentration data of the disinfectant detected by concentration sensor 720 and/or the flow meter data from flow meters 125 and 225 may be displayed and used by a user to determine whether the system is functioning abnormally, e.g. a drop in flow rate may indicate a blockage such that the user may manually switch to a bypass mode of operation.

Each constituent unit 110, 200, 300, 400 of the system 100, 102 described above in relation to Figures 3 to 6 may be either activated or deactivated, depending on the required operation, by the opening or closing of the valves controlled by the controller 700. The method of operating the system 100, 102 will now be described in relation to Figures 7 and 8. Raw water enters the system 100, 102 through the main line 105 which provides the input to Pre-Treatment Unit 110. If the Pre-Treatment unit 110 is operationally active, it is configured such that bypass valve 540 is closed and automatic valve 525 is set to normal open filter operation. As valve 540 is closed, the water entering the Pre-Treatment unit via main line 105 is directed into the sand filter 530 via the pre-treatment filter line 520. On output from the filter 530, the pre-treated water passes along the line 560, through junction 550 to water inlet line 115.

If the Pre-Treatment unit 110 is operationally deactivated, for example, if the filter system is being serviced, or there is a blockage in one of the lines 520 or 560, the automatic valve 525 is closed and bypass valve 540 is open such that the raw water instead flows through the bypass line 515 via junction 510 and is output back into the water inlet line 115 through output junction 550.

If Dosing System 300 is active, 340 is closed and automatic valve 325 is set to normal open operation such that the water output from the Pre-Treatment unit 110 passes along the water inlet line 115 to junction 120 where at least a portion of the water supply is directed into dosing water line 140. The amount of water input to the Dosing System 300 may be controlled in any suitable or desirable way, including but not limited to the diameter of the piping (wherein a smaller diameter will result in a reduced volume of water passing through the Dosing System 300 and an increased diameter will result in an increased volume of water passing through the Dosing System 300) or a regulating valve device wherein the size of the valve opening may be used to vary the volume of water that passes through the Dosing System 300.

If the Dosing System 300 is deactivated, e.g. there is no requirement for medicine to be administered at that time, both valves 325 and 340 are closed such that the water output from the Pre-Treatment unit 110 passes through junction 120 into the Disinfection System 200 via water inlet line 130. The flow rate of the water is measured by a first flow meter 125 positioned in the water inlet line 130 before the water reaches the plurality of dilution line input junctions 210a and 210b which feed into the plurality of dilution lines 215a and 215b. Dilution control valves 250a and 250b set the total volume of water that flows in the dilution lines 215a and 215b respectively as a second water supply. In the embodiment shown in Figure 7, dilution control valve 250a is a regulating valve such that the size of the valve opening may be varied. In contrast, dilution control valve 250b is an on/off valve that may only be set to be open or closed. In some embodiments both dilution control valves 250a and 250b may be selected to be regulating valves. Water that does not pass into dilution lines 215a and 215b instead passes through junctions 210a and 210b to the disinfection inlet 220 of the Disinfection unit 400, where the flow rate of the first water supply is measured before the water reaches the bypass junction 410 by a second flow meter 225 positioned at the disinfection inlet 220.

If the disinfection unit 400 is operationally active, bypass valve 490 and exhaust valve 495 are closed, preventing the flow of water through bypass line 420 or out of the system respectively, and valves 425 and 480 are open such that the water passes through disinfection line 415 towards the plurality of treatment cartridges 450a to 450e via junctions 430a to 430c that define the parallel arrangement. The disinfection cartridges 450a-450f are selected to be cartridges comprising a medium including releasable oxidative bromine, such as HaloPure™ cartridges containing brominated polystyrene hydantoin beads.

The disinfection unit 400 may be configured such that any suitable or desirable number of disinfection cartridges 450n may be available for water to pass through by opening or closing respective cartridge control valves 445n. When the disinfection cartridges 450n are first installed into the system, the concentration of biocidal species (e.g. bromine) released from a disinfection cartridge 450n into the water passing through the unit 200 (e.g. by the control release of oxidative bromine from the brominated polystyrene hydantoin beads in a HaloPure™ cartridge) will be at highest levels due to the initial fast release of biocidal species (e.g. oxidative bromine) that is not stably bound to the medium (e.g. the polystyrene hydantoin beads).

If all of the controllable valves 445a-445f are set to be open such that all disinfection cartridges 450a-450f are available for water to pass through, the volume flow rate of the water in each branch 440a-440f will be effectively a sixth of the flow rate measured at the second flow meter 225. As the release of the biocidal species is determined by the dissociation constant which is in turn an equilibrium constant, high flow rates result in the equilibrium being shifted to the right and the dissociation of the biocidal species increasing as the water carries the biocidal species away more quickly. In contrast, when the flow of water through the cartridges is slower, the equilibrium is positioned further to the left resulting in a reduced release of the biocidal species (e.g. oxidative bromine) from the medium (e.g. polystyrene hydantoin beads) due to a prolonged period of contact (and thus establishment of the equilibrium) when compared to a greater flow rate.. The concentration of biocidal species in the water output from the Disinfection unit 400 is thus increased when all disinfection cartridges are available compared to an equivalent system where only one cartridge is active (for example).

It is desirable that the concentration of biocidal species in water output from the disinfection unit 400 is high enough that pathogenic microorganisms and/or biofilm build up in water pipelines downstream of the disinfection unit may be effectively inactivated or prevented. A very low concentration of biocidal species from the disinfection system 200 is thus undesirable, as there may not be a sufficient dose of biocidal species to inactivate the pathogens and biofilms present between the output of the disinfection system and the drinking line. In embodiments of the present invention where the biocidal species released into the water by the disinfection unit 400 is selected to be residual bromine (e.g. from halogenated polystyrene hydantoin beads in a HaloPure™ cartridge), it is envisaged that a concentration lower than 0.5 ppm or 0.3 ppm would be too low for effective disinfection. A desirable concentration of residual bromine in drinking water for animal consumption is about 1 ppm. A desirable concentration of residual bromine in drinking water for animal consumption is in the range of 0.3 ppm to 2 ppm.

It has been found that a concentration of about 1 ppm residual bromine as a biocidal species is an efficacious level to inactivate pathogens and biofilm formation downstream of the disinfection system, whilst maximising the efficacy of the disinfection cartridges across their lifetime without unnecessary depletion of the biocidal species.

By way of an example, Figure 9a shows a schematic representation of the concentration of releasable biocidal species bound within the disinfection cartridge medium as a function of the total volume of water that has passed through the disinfection cartridge (e.g. the total volume of water that has come into contact with the disinfection cartridge medium). As has previously been discussed, when water comes into contact with the disinfection cartridge medium, a biocidal species (“biocide”) is released into the water. Thus, when the total volume of water that has passed through the disinfection cartridge is low, the amount of biocidal species comprised within the medium is high as only a small amount of biocidal species has been released into the water (e.g. left cartridge of Figure 9a). As the volume of water increases (e.g. moving from left to right in Figure 9a), the amount of the biocidal species decreases (e.g. non-linearly) as there is increased contact with the medium. Once there is only a low amount (e.g. 25%) of biocidal species left then the medium may be replaced or recharged with the biocidal species. For example, when the disinfection cartridge medium is a N-halamine polymer resin bead and the releasable biocidal species is oxidative bromine this means that the fully charged (e.g. biocidal active) medium has bromine chemically bound to the amide nitrogen and/or the imide nitrogen of the N-halamine polymer resin bead. Thus, when water comes into contact with the charged medium, bromine is dissociated from the imide and/or amide nitrogens and released into the water. As the imide-halogen bond is weaker (with a higher dissociation constant) than the amide-halogen bond, initially (e.g. when the total water volume that has come into contact with the medium is low) the bromine will be released from the less stable (e.g. imide) position and the concentration of bromine reversibly bound to the medium (e.g. the concentration of charged polymer beads) remains high (e.g. left cartridge in Figure 9a). As the total volume of water increases, the dissociation in the imide position continues and the dissociation of bromine in the amide position increases such that the amount of bromine bound to the medium (e.g. the amount of charged polymer beads) is depleted (e.g. moving left to right in Figure 9a).

As such, it will be appreciated that the concentration of biocidal species released into the water as water flows through the cartridge depends on the total volume of water that has come into contact with the medium (e.g. since the medium was installed or last replenished with the biocidal species).

By way of an example, Figure 9b shows the typical bromine release profile expected for a single HaloPure™ cartridge comprising 30 kg of halogenated polystyrene hydantoin beads as a function of the total volume of water (in metric tonnes) that has passed through the cartridge. The concentration of bromine in the disinfected water is measured in parts per million (ppm). The different traces represent different flow rates of water (in metric tonnes per hour) through the cartridge. As can be seen, initially, when the beads are fully dosed and the total water that has passed through the cartridge is low, there is a high release of bromine into the water passing through the cartridge. This is because there will be a relatively large amount of bromine that is unstably bound to the hydantoin beads and thus preferentially released. This initially results in a high concentration of residual bromine > 1 ppm in the water but this “High Bromine” stage is short-lived, e.g. only lasting for the first 400 MT (Metric Tonnes) of water passing through the disinfection cartridge. However, it will be appreciated that the total volume of water corresponding to the “High Bromine” stage will vary depending on the size of the cartridge and the quantity of the medium (e.g. halogenated polystyrene hydantoin beads) therein. As Figure 9b shows, the concentration of residual bromine released by the HaloPure™ cartridge is initially high (“High Bromine” Stage 1) but then falls rapidly below 1 ppm as the total volume of water is increased. After the concentration of residual bromine falls below 1 ppm, the release profile flattens showing a controlled stable release of residual bromine with respect to increasing volume of water, across a “Stable Bromine” Stage 2 between about 400 and 3000 MT in this example. The residual bromine concentration starts to drop below 0.5 ppm at approximately 3000 MT of water and then a “Low Bromine” Stage 3 can be defined for the final 3000-5000 MT of water passing through the cartridge, where the beads become depleted. In addition to these three main stages, the total (i.e. cumulative) water volume can be used to define multiple disinfection stages across the release profile.

It will be appreciated that the release profile, regardless of the size of the cartridge, will observe the same behavioural profile (e.g. the same release trend as a function of volume) as the release profile is determined by the physical dissociation constant of the biocidal species in water. Thus, the data shown in Figure 9b may be scaled up or down (e.g. linearly, e.g. non-linearly) to represent the expected release profile for any suitable or desirable cartridge size (e.g. mass of medium including the releasable biocidal species).

It will thus be appreciated from Figure 9b that a single HaloPure™ cartridge containing 30 kg of beads may only provide water with desirable concentrations of bromine for use in disinfection between approximately 500 MT and 2500 MT of total water passed through the cartridge, resulting in the water output from such cartridges at volumes less than 500 MT and volumes greater than 2500 MT containing bromine but not at the desired concentration. This leads to significant levels of the bromine from the disinfection cartridges being wasted as well as a significant volume of wasted water resource. As such, without a system and method of control as is envisaged by the present invention, such a HaloPure™ cartridge may be considered to engender too high waste and usage costs, e.g. stemming from frequent recharge or replacement requirements, to be economically viable for provision of drinking water for animal farms.

It is therefore desirable to control the concentration of bromine released by such disinfection cartridges to achieve the residual bromine disinfectant at an efficacious level to inactivate pathogens and biofilm formation downstream of the filter system (e.g. above 0.5 ppm, or above 0.3 ppm, for residual bromine) whilst maximising cartridge lifetime by minimising unnecessary depletion and ensuring that the water supply at point of consumption has a desirable concentration level e.g. in the range of 0.3-2ppm (e.g. about 1 ppm for residual bromine). The Stages 1-3 mentioned above are seen to apply generally regardless of the flow rate of water through the cartridge. However, it can also be seen from Figure 9b that the flow rate affects how quickly the cartridge moves between the stages, for example the highest flow rate of 60 MT/hr results in the High Bromine stage (>1 ppm) only lasting for the first 300 MT of water and the Stable Bromine stage having a shorter duration, e.g. between about 300 MT and 2000 MT, before the concentration of residual bromine drops to 0.5 ppm and the cartridge needs to be recharged or replaced. Thus flow rate is another parameter to take into account.

The problems discussed above apply to any type of disinfection cartridge comprising a medium including a releasable biocidal species that is released into water coming into contact with the medium as water flows through the cartridge, as the amount of the biocidal species that is released may depend on the total volume of water that has come into contact with the medium and/or the flow rate of water passing through the cartridge.

It is therefore beneficial to adjust the concentration of biocidal species in water that has passed through a disinfection cartridge (of the type comprising a medium including a releasable biocidal species) by taking into account the total volume of water that has passed through the cartridge and/or the current flow rate of water passing through the cartridge.

This adjustment may take place downstream of the disinfection cartridge(s) by combining the disinfected water supply with another water supply (e.g. dilution) and/or by further treating the disinfected water supply using a medium arranged to reversibly bind with the biocidal species in the disinfected water supply (e.g. balancing). Examples of both of these approaches are described further below.

There will now be described three example control schemes for the disinfection system 200 seen in Figures 3-4 and 7-8.

Example 1 - Operation of cartridge control valves

As described above, at an early stage in a cartridge’s lifetime the resultant release of biocidal species from the medium will be high such that it is preferable to have a high flow rate through the cartridge (i.e. low contact time) with only one cartridge active. As such, the controller 700 will configure the system such that it operates in a one-cartridge cycle. In a one-cartridge cycle, only one cartridge 450a is available for water to pass through and therefore the controller 700 configures the system such that the cartridge control valve 445a is open and all other cartridge control valves 445b to 445f are closed. The controller 700 then monitors the flow rate of the first water supply at the disinfection inlet 220 via the second flow meter 225 such that the total volume of water that has passed through the cartridge 450a may be monitored. When the volume of water that has passed through the cartridge 450a is determined to exceed the pre-determined threshold level for a one-cartridge cycle, the controller 700 closes its associated cartridge control valve 445a and opens another cartridge control valve 445b such that the first water supply input to the unit 400 via the disinfection inlet 220 is now directed through the cartridge 450b and the process is repeated. Once all cartridges 450a-450f have had an equal amount of water pass through, the controller 700 can determine whether to repeat the one-cartridge cycle or change the operation to another cartridge cycle, e.g. a three-cartridge cycle.

It will be appreciated that in an n-cartridge cycle the controller 700 will configure the disinfection unit 400 such that n cartridge control valves 445n are open at any one time. For example, in a three-cartridge cycle, the controller 700 may first open the cartridge control valves 445a, 445b and 445c. When the volume of water passing through the unit 400 exceeds the pre-determined threshold level for a three-cartridge cycle, the controller 700 closes the cartridge control valves 445a, 445b and 445c and opens the cartridge control valves 445d, 445e and 445f and the process is repeated.

The controller 700 may determine the n-cartridge cycle by any suitable or desirable method. For example, the cartridge cycle sequence may be pre-programmed using simulated, theoretical or experimentally determined biocidal release profiles (such as that shown in Figure 9b) such that the cartridge cycles are pre-set according to the prevailing high/stable/low stage and thus changed only as a function of the total volume of water that has passed through the disinfection unit 400 as measured via the flow meter 225.

In some embodiments, at least one sensor may be positioned after the disinfection unit 400 such that the biocidal species (e.g. bromine) concentration may be periodically determined in situ using the sensor data and the controller 700 may change the n-cartridge cycle as a result of the biocide concentration feedback.

Introduction to External Dilution Control

It has been appreciated that selectively operating the cartridge control valves 445n, e.g. in n- cartridge cycles as described above, can help to achieve a more steady concentration of the biocidal species in water leaving the disinfection unit 400 despite the typical release profile seen in Figure 9b. However, there can be serious limitations to this approach used alone. In many water treatment systems it may not be viable to install a large number of cartridges and frequently replace or recharge the cartridges. The inventors have therefore devised some dilution approaches whereby the controller 700 is programmed to selectively open one or more dilution control valves 250, 250a, 250b so as to adjust the final concentration of biocidal species in the water leaving the disinfection system 200 across the entire release profile of a given cartridge.

Example 2 - Basic dilution control

In embodiments of the present invention, the controller 700 is programmed to provide biocide concentration control by pre-setting a dilution ratio based on flow rate, with the pre-set dilution ratio being assigned depending on the total water volume (as measured by one or both of the flow meters 125, 225) so as to account for the release profile of the disinfection cartridge(s) in the disinfection unit 400. The controller 700 is arranged to operate one or more dilution control valves 250n and/or the disinfection control valve 425 to achieve the preset dilution ratio at any given time. The flow rate may be pre-programmed (e.g. an expected or average flow rate may be input by a user) or the controller 700 may measure the flow rate e.g. using the flow meter 125, for example as an initial step. The dilution ratio at any point in time is defined as the flow rate through the water inlet line 130 divided by the flow rate through the disinfection inlet 220.

For example, if the volume measured at flow meter 125 is 500 MT and the volume of water that is measured at flow meter 225 is 250 MT, and 6 minutes later the volume measured at flow meter 125 is 505 MT and the volume of water that is measured at flow meter 225 is 251 MT, the flow rate of water passing into the Disinfection System 200 via the water inlet line 130 may be calculated to be 50 MT/hr and the flow rate of water passing into the disinfection unit 400 via the disinfection inlet 220 may be calculated to be 10 MT/hr. The dilution ratio would thus be 5 and the concentration of biocidal species output from the Disinfection System 200 would be a fifth of that output from the disinfection cartridges 450n.

In such embodiments, the controller 700 uses the flow meter 125 to determine the total volume of water passing into the Disinfection System 200 and/or the flow meter 225 to determine the total volume of water passing into the disinfection unit 400. Depending on the total (e.g. cumulative) volume of water that has passed into the Disinfection System 200 (e.g. as measured by the flow meter 125), or the total (e.g. cumulative) volume of water that has passed into the disinfection unit 400 (e.g. as measured by the flow meter 225), a disinfection phase is set and each disinfection phase is associated with a pre-set dilution ratio. The preset dilution ratios may, for example, have been determined from typical or expected release profiles for the disinfection cartridges installed in the disinfection unit 400. The release profiles may be based on empirical, experimental or theoretical data. For each phase, the controller 700 re-configures the system 200 to effect the pre-set dilution ratio, e.g. by opening or closing the dilution control valve(s) 250, 250a, 250b to effect a greater or lesser dilution respectively. Such dilution control can be understood with reference to Figure 3 or Figure 7.

As described above, the release of biocidal species from the medium contained within a cartridge 450 is dependent on the volume of water that has passed through the cartridge and come into contact with the medium. For example, at an early stage in a cartridge’s lifetime the resultant release of biocidal species from the medium in a one-cartridge cycle may still be higher than is desirable and thus the controller 700 is programmed in the early phases to effect a high dilution ratio. This will be understood more clearly with reference to Table 1 below. The controller 700 determines the phase of the system by measuring the total volume of water that has passed into the Disinfection System 200 and/or disinfection unit 400 using flow meter 125 and/or flow meter 225.

In some embodiments comprising a first and second flow meter both before and after the dilution junction 210 as shown in Figure 7 (e.g. flow meter 125 and flow meter 225 respectively), the total volume of water that has passed into the disinfection unit 400 may be measured directly via the flow meter 225 and the total volume of water that has passed into the dilution line(s) 215 may be determined as the difference between the total volume of water measured to enter the Disinfection System 200 via flow meter 125 and the total volume of water that has passed into the disinfection unit 400 as measured by the flow meter 225.

For example, the system 200 comprises a plurality of HaloPure™ disinfection cartridges 450n expected to have the typical release profile illustrated by Figure 9b but with a “high bromine” Stage 1 up to 1000 MT for the total volume of water passing into the disinfection unit 400 (and therefore passing through each cartridge 450n in a parallel arrangement). The controller 700 determines from the release profile (e.g. stored within the memory of the controller 700) that the concentration of biocidal species is expected to be higher than 1 ppm even for a single cartridge during Stage 1. The controller 700 therefore opens only one of the cartridge control valves 445n and the system is configured to operate in several phases whereby only one cartridge is active at a time. Furthermore, to control the final concentration of biocidal species in water leaving the system 200, the disinfection control valve 425 and the dilution control valve(s) 250, e.g. as seen in Figures 3 and 7, are selectively opened or closed to achieve the pre-set dilution ratio associated with the current phase. As mentioned previously, one or more of the controllable valves 425, 250 can be on/off valves that are either open or closed. However, an advantage of a regulating valve is that the dilution ratio can be achieved more accurately.

The controller 700 determines the applicable phase at any time based on the cumulative volume of water that has entered the disinfection inlet 220. Table 1 below provides an example of the phases during operation up to a total water volume of 25,000 MT. After the phase has been determined, the controller 700 will operate the dilution control valves 250n and/or the disinfection control valve 425 to achieve the pre-set dilution ratio assigned to that phase. The controller 700 may have, e.g. stored in a look-up table within its memory, preprogrammed settings for every control valve in the system 200 for every possible phase. Thus, once the controller 700 has determined the phase, it will retrieve the required control valve settings for that phase from the memory (e.g. the number of cartridges to be active and the position of the control valves 425 and 250n) and thus transmit signals to the control valves to effect this configuration.

For example, Table 1 below provides a theoretical exemplary schedule of operation of the Disinfection System 200 (comprising only one dilution line 215 and one dilution control valve 250, e.g. as seen in Figure 3) as controlled by the controller 700 in embodiments where the disinfection phase is defined by the total volume in Metric Tonnes (MT) of the water supply as measured by the first flow meter 125 (although it will be appreciated that the phases may instead be defined by the total volume as measured by the second flow meter 225, taking into account that the water supply has already been split upstream at the junction 210 between the disinfection inlet 220 and the dilution line 215).

It can be seen that in Stage 1, up to 1000 MT, there are 13 phases based on the total volume and in each of these phases the dilution control valve 250 is 100% open so as to reduce the final concentration. In the initial phases, the disinfection control valve 425 is only opened to a small degree so as to restrict the volume of water passing through the cartridge 450. As the total volume increases the disinfection control valve 425 is gradually opened to a larger degree. The overall effect is that the final concentration can be maintained at about 1 ppm on average. In Stage 2, from about 1000 MT to about 20,000 MT, the disinfection control valve 425 is 100% open as there is a stable release from the cartridge 450. In Stage 2 the dilution control valve 250 is less than 100% open, gradually closing as the system moves from phase 14 to phase 29, because the concentration is steadily decreasing and less dilution is required as the total volume increases. In Stage 3, the final phase for 20,000-25,000 MT, the dilution control valve 250 is fully closed and the disinfection control valve 425 is still 100% open but the concentration will start to drop below the desired level as the cartridge 450 becomes depleted. The cartridge 450 should be replaced or replenished after phase 30. Table 1 : Exemplary phases during basic dilution control

A pre-set dilution ratio is assigned to each phase, although the dilution ratios are not shown in Table 1. For example, if the controller 700 determined from the flow data measured by the flow meter 125 that the total volume was 450 MT, the controller 700 would determine that the Disinfection System 200 should be configured to meet the dilution requirements of Phase 9, configuring the disinfection control valve 425 to be 50% open and the dilution control valve 250 to be 100% open such that the flow rate of water into the dilution line 215 is twice as great as the flow rate into the disinfection unit 400 and thus the concentration of biocidal species is effectively diluted by two times to thereby achieve the preset dilution ratio of 2.

Although Table 1 only shows that a change in phase is accompanied by a change in the configuration of the control valves 425 and 250, it will be appreciated that the settings for each phase may further comprise any suitable and/or desirable instructions and/or valve configurations in addition to the control valve settings shown in the table. For example, the controller 700 may further configure the system 200 to achieve the desired concentration by changing the required number of cartridges to be used (e.g. n-cartridge cycle). For example, when there are two dilution lines 215a and 215b (as shown in Figure 7) the controller 700 may operate the on/off dilution control valve 250b to be either open or closed and operate the regulating dilution control valve 250a (between 0 and 100% open) to fine tune the water supply used for dilution and hence achieve the pre-set dilution ratio more accurately. For example, to effect a dilution of 6 times in some systems, the controller 700 may configure the on/off dilution control valve 250b to be open and the regulating dilution control valve 250a to be 50% open.

Furthermore, it will be appreciated that this schedule may be applied to any number of dilution control valves 250n and/or cartridge control valves 445n. For example, with reference to Figure 7, every disinfection line 440a to 440f could have an associated regulating control valve such that the flow of water through the parallel arrangement of disinfection cartridges 450a to 450f may be independently and finely controlled.

In some examples relating to Figure 3, the dilution ratio may be controlled by controlling both the dilution line 215 and the disinfection unit 400 via the control valves 425 and 250, as described in relation to Table 1. In some other examples relating to Figure 3, the dilution ratio may be solely controlled using the dilution line 215 by the controller 700 configuring the dilution control valve 250 to open to a varying extent, thus changing the volume of water entering the dilution line 215, based on the determined phase. This approach may be more reliable when the system 200 includes multiple dilution lines, such as the dilution lines 215a, 215b seen in Figure 7. As mentioned above, the dilution control valve 250a may be opened to a variable degree to effect fine flow control while the dilution control valve 250b may be opened or closed to effect coarse flow control.

In this basic dilution approach, the pre-set dilution ratios assigned for each phase may be determined in advance (and stored in the controller 700) based on an expected average flow rate of water through the disinfection system 200. However, in many water treatment systems the flow rate may at times deviate considerably from the average, which has an effect on the release rate of the biocidal species (as seen in Figure 9b) and hence the final biocide concentration.

While this basic dilution control approach has been found to achieve a desired biocide concentration within acceptable limits, e.g. 1.0 ± 0.5 ppm, the concentration is subject to fluctuations and this may be exacerbated when the flow rate through the disinfection system 200 is variable. For example, the drinking water demand in an animal farm can vary greatly at different times of the day and night.

Example 3 - Advanced dilution control

In more advanced embodiments of the present invention, the controller 700 is programmed to provide an intelligent concentration control whereby the controller 700 actively calculates an actual dilution ratio in situ using not only total water volumes measured by the flow meter 125 and/or the flow meter 225, but also a flow rate e.g. measured by one or more of the flow meters 125, 225. In these embodiments, once the controller 700 has determined the phase based on total water volume, the controller 700 may further determine a sub-phase within that phase, wherein the sub-phase is based on flow rate. This provides a more sophisticated and intelligent concentration control and allows the position of the dilution control valve(s) 250 and/or disinfection control valve 425 to be re-configured within any given phase to respond to different flow rates. The flow rate may be an actual flow rate e.g. measured in real time, or an expected flow rate e.g. pre-programmed based on a time schedule.

Table 2: Exemplary phases and sub-phases during advanced dilution control

In these embodiments the system’s configuration (e.g. disinfection phase) is determined from the total volume of water determined from the data measured by flow meter 125 and/or flow meter 225, in the same way as Example 2. For example, the disinfection phase of the system 200 may be determined based on the expected release profile for the treatment cartridges 450n (as described above in relation to the simpler system). The disinfection sub-phase of the system 200 is then defined by the flow rate, e.g. as measured for the water supply flowing through the water inlet line 130 by flow meter 125. Once the disinfection phase and sub-phase have been determined, the controller 700 may configure the system 200 to effect the desired dilution ratio for that combination of disinfection phase and sub-phase. This allows the system 200 to react to changes in flow rate that would otherwise affect the final biocide concentration.

To illustrate an example of advanced dilution control, Table 2 below provides an exemplary schedule of operation of the Disinfection System 200 seen in Figure 7 as controlled by the controller 700 where the disinfection phase is defined by the Total Volume in Metric Tonnes (MT) as measured by the first flow meter 125, the sub-phase is defined by the flow rate as measured by the flow meter 125, and the dilution ratio is controlled only by operating the dilution control valves 250a and 250b. In this example the n-cartridge cycle is also adjusted as already described in Example 1. By increasing the number of active disinfection cartridges during later phases, Stage 3 can be extended as compared to Example 2 for a single cartridge.

In some embodiments, the schedule (e.g. as defined by the table above) may be preprogrammed into the controller 700 such that the controller 700 receives the data from the first flow meter 125 indicating the Total Volume of water, from which the applicable phase is determined, and the flow rate, from which the applicable sub-phase is determined. For example, if the flow meter 125 measures that the Total Volume that has passed through the water inlet line 130 is 500 MT and the rate of flow is 20 MT/hr, the controller 700 will determine that the Disinfection System 200 should be configured to meet the requirements of Phase 6.3 (e.g. phase 6, sub-phase 3). The controller 700 will thus (in accordance with Phase 6.3) configure the disinfection unit 400 to operate in a one-cartridge cycle with the coarse dilution control valve 250b configured to be closed and the fine dilution control valve 250a configured to be 25% open such that the expected dilution ratio of 2 is effected (e.g. there is a 1:1 ratio of water combining at junction 240 from the dilution lines 215a, 215b and disinfection outlet 230).

Once the system has been configured to effect the desired dilution ratio, the controller 700 periodically (e.g. every 5 minutes) calculates the actual dilution ratio by calculating the flow rate of water passing into the Disinfection System 200 and the flow rate of water passing into the disinfection unit 400 from the total volume of water as measured periodically by flow meters 125 and 225. In some embodiments, the controller 700 further calculates the actual dilution ratio at periodic intervals by dividing the flow rate of water entering the Disinfection System 200 (e.g. measured by flow meter 125) by the flow rate of water entering the disinfection unit 400 (e.g. measured by flow meter 225). If the actual dilution ratio calculated by the controller 700 is different to the desired i.e. target dilution ratio for a given sub-phase, the controller may reconfigure the system to effect the desired concentration (e.g. by opening or closing a regulating dilution control valve 250a to effect greater or lesser dilution factor respectively).

For example, when the system 200 is configured to operate in Phase 6.3 (as described above), if flow meter 125 measures a flow rate of 20 MT/hr and flow meter 225 measures a flow rate of 5 MT/hr of the water entering the disinfection unit 400, the actual dilution ratio would be 4, rather than the desired 2. As such, the controller 700 may re-configure the system to close the dilution control valve 250a further (e.g. by a further 50%) to a value of 12.5% to increase the flow rate of water through the treatment unit 400 and thus reduce the dilution ratio.

The controller 700 thus uses the flow rate data received by the controller 700 from flow meter 125 and/or 225 to provide a dynamic feedback control and if necessary update the configuration of the fine dilution control valve 250a to maintain the flow rate (and hence biocide concentration) within the required range. It will be appreciated that the actual dilution ratio may be calculated at any suitable and/or desirable periodic interval. Furthermore, the periodic intervals may be variable as a function of the phase. For example, it may be appreciated from the release profile shown in Figure 9b that the actual dilution ratio may need to be calculated more frequently in Stage 1 (e.g. early phases) when the concentration changes quickly compared to later times in Stage 2 or Stage 3 (e.g. later phases) when the release profile is shallower and the change in biocide concentration with respect to the volume of water passing through the system is at a slower rate. As such, Phase 1 may be expected to have a smaller periodic interval for calculating the actual dilution ratio (e.g. 5 minutes) compared to Phase 30 (e.g. 1 hour).

In the example seen in Figure 7, the system 200 comprises six disinfection cartridges 450a- 450f and two dilution lines 215a and 215b with a regulating dilution control valve 250a and on/off dilution control valve 250b respectively. However, it will be appreciated that the same principles of basic or advanced dilution control may be applied to any suitable and/or desirable embodiment of the water treatment system 100, 102 described herein.

Thus, to further illustrate this procedure, the table below provides an alternative exemplary schedule of operation to that provided above for controlling the operation of a system 100, 102 wherein there are only two filter cartridges 450 in disinfection unit 400 and a single dilution line 215, as seen in Figures 3-4. The dilution ratio is controlled by controlling both the dilution line 215 and the disinfection unit 400 via the control valves 425 and 250 (e.g. both control valves 425 and 250 are regulating valves which may be configured by the controller 700).

Table 3: Exemplary phases and sub-phases during advanced dilution control

For example, if the flow meter 125 measures that the Total Volume that has passed through the water inlet line 115, 130 is 500 MT and the rate of flow is 20 MT/hr, the controller 700 will determine that the Disinfection System 200 should be configured to meet the requirements of Phase 3.3 (e.g. phase 3, sub-phase 3). The controller 700 will thus (in accordance with Phase 3.3) configure the disinfection unit 400 to operate in a one-cartridge cycle with the dilution control valve 250 configured to be 100% open and the disinfection control valve 425 configured to be 45% open such that the target dilution ratio of 5 is effected (e.g. there is a 1 :4 ratio of water combining at junction 240 from dilution line 215 and disinfection outlet 230).

In some embodiments, the controller 700 further calculates the actual dilution ratio at periodic intervals by dividing the flow rate of water entering the Disinfection System 200 (e.g. measured by flow meter 125) by the flow rate of water entering the disinfection unit 400 (e.g. measured by flow meter 225). If the actual dilution ratio calculated by the controller 700 is different to the desired i.e. target dilution ratio for a given sub-phase, the controller 700 may reconfigure the system 200 to effect the desired concentration (e.g. by opening or closing the dilution control valve 250 to effect greater or lesser dilution factor respectively).

For example, when the system 200 is configured to operate in Phase 3.3 (as described above), if flow meter 125 measures a flow rate of 20 MT/hr and flow meter 225 measures a flow rate of 5 MT/hr for the water entering the disinfection unit 400, the actual dilution ratio would be 4, rather than the desired 5. As such, the controller 700 may re-configure the system 200 to open the dilution control valve 250 further and/or close the disinfection control valve 425 more such that the dilution ratio is increased.

The controller 700 thus uses the flow rate data received by the controller 700 from flow meter 125 and/or 225 to provide a dynamic feedback control and if necessary update the configuration of the dilution control valve 250 to maintain the flow rate (and hence the concentration) within the required range.

Introduction to Internal Dilution Control

Thus far it has been described how some embodiments of the present invention solve the technical problem of regulating the concentration of a biocidal species released into drinking water by combining the treated water output from the Disinfection unit 400 with a second supply of water that has not been disinfected in the same way (e.g. substantially null concentration of the biocidal species) via dilution lines 215n, wherein the dilution ratio is adjusted by the controller 700 by operating one of more dilution control values 250n, e.g. as shown in Figures 3 and 7.

However, it will be appreciated that the solution provided by such embodiments results in potentially large volumes of water that has not been disinfected being combined with the water intended to be consumed downstream. This is potentially undesirable as the second supply of non-disinfected water may potentially contain harmful pathogens and biofilms that it is the object of the present invention to reduce.

As such, some embodiments of the present invention utilise an alternative Disinfection System to that depicted in Figure 3 and Figure 7 (e.g. comprising external dilution lines 215n) whereby both the first water supply (e.g. the disinfected water supply) and the second water supply (e.g. the dilution water supply) come into contact with a biocidal medium such that all water is disinfected to a degree.

Figure 10 and Figure 11 schematically represent one such alternative Disinfection System 202 configuration that provides internal dilution within the Disinfection unit 402 rather than external to it (as is shown in Figures 3 and 7).

Figure 10 shows a Disinfection System 202. Similar to Disinfection System 200, a first water supply is input to the Disinfection System 202 through a water inlet line 130 (or 132).

However, in contrast to Disinfection System 200, the inlet line 130 is not then split into two separate water supplies (e.g. disinfection inlet 220 and dilution line(s) 215n) at a dilution line input junction 210. Instead, all water that is input to Disinfection System 202 via line 130 is provided as an input to the disinfection Unit 402 via the disinfection inlet 220. Disinfection unit 402 outputs clean (e.g. disinfected) drinking water via the disinfection outlet 230 which has already been diluted to the desired concentration internally within the Disinfection unit 402. Hence an external dilution output junction 240 is not required.

Figure 11 shows an example embodiment of a Disinfection unit 402 comprising internal dilution (e.g. a system of dilution whereby all water comes into contact with a biocidal medium and is thus disinfected to a degree). The disinfection inlet 220 provides the input to the Disinfection unit 402 and is split, at bypass junction 410, into a disinfection line 415 and a bypass line 420. Bypass line 420 provides a bypass path which outputs at junction 470.

Bypass valve 490 is located in the bypass line 420. Two valves (disinfection control valve 425 and exhaust valve 495) are disposed in the disinfection line 415 between the junction 410 and a dilution branch junction 1130. The exhaust valve 495 may be operated to exhaust some of the water supply to a waste output line 500, e.g. in the event of a blockage in the Disinfection unit 402.

The disinfection line 415 splits at the dilution branch junction 1130 to provide an input to both a dilution line 1215 and a main disinfection line 1220. The main disinfection line 1220 splits at another branch junction 430 to provide an input to the plurality of disinfection cartridges 450 arranged in parallel via branch lines 440. Two disinfection cartridges 450 in a parallel arrangement are shown in Figure 11, but the main disinfection line 1220 may pass through only one or several disinfection cartridges 450 arranged in series and/or in parallel.

Alternative embodiments may include any suitable or desirable number of disinfection cartridges 450n, where n >1 , e.g. six cartridges as seen in Figure 7.

A flow meter 225 is shown to be positioned in the main disinfection line 1220 between the dilution branch junction 1130 and junction 430. However, in some embodiments it will be appreciated that alternatively, or in addition to the flow meter 225 positioned before the junction 430, each branch line 440 may include a flow meter upstream of its disinfection cartridge(s) 450. Use of the flow meter 225 by a controller 702 will be described below with reference to Figure 13.

Each branch line 440 has positioned along its length a cartridge control valve 445 e.g. disposed between the disinfection cartridge(s) 450 and branch junction 430. The cartridge control valves 445 may comprise any suitable and/or desirable valve, e.g. an on/off valve (providing only on/off or open/closed functionality) and/or a regulating valve. The water output from the disinfection cartridges 450 converges to a main disinfection outlet line 465 at an output junction 460.

The dilution line 1215 splits at a branch junction 1430 to provide an input to a plurality of dilution line disinfection cartridges 1450 arranged in parallel via the branch lines 1440. A flow meter 1225 is positioned in the dilution line 1215 between the dilution branch junction 1130 and branch junction 1430. However, in some embodiments it will be appreciated that alternatively, or in addition to the flow meter 1225 before the branch junction 1430, each branch line 1440 may include a flow meter upstream of its dilution line disinfection cartridge 1450. Use of the flow meter 1225 by a controller 702 will be described below with reference to Figure 13. Each branch line 1440 has positioned along its length a dilution control valve 1250 e.g. disposed between the dilution line disinfection cartridge(s) 1450 and branch junction 1430. The dilution control valves 1445 may be any suitable and/or desirable valve, e.g. an on/off valve (providing only on/off or open/closed functionality) and/or a regulating valve. The water output from the dilution line disinfection cartridges 1450 converges to a dilution outlet line 1465 at a dilution output junction 1460.

It will be appreciated that although this example depicts two dilution line disinfection cartridges 1450 arranged in parallel along the dilution line 1215, alternative embodiments may include any suitable or desirable number of dilution line disinfection cartridges 1450n, where n >1 , e.g. six cartridges as seen in Figure 7, arranged in any suitable and/or desirable configuration, e.g. in series and/or in parallel.

Furthermore, it will be appreciated that although the dilution line 1215 is depicted in Figure 11 to substantially mirror the same downstream configuration as disinfection line 1220, any suitable and/or desirable configuration may be used. For example, there is no reason for the number of disinfection cartridges 450 to be equal in number to the number of dilution line disinfection cartridges 1450, nor is there a need for the dilution line disinfection cartridges 1450 to be arranged in series/parallel if the plurality of disinfection cartridges 450 in the disinfection line 1220 are arranged in series/parallel.

The purpose of the second water supply carried by the dilution line 1215 is to dilute the concentration of the biocidal medium released into the first water supply carried by the disinfection line 1220, meaning that the concentration in the second water supply is less than in the first water supply. The disinfection outlet line 465 and dilution outlet line 1465 then converge at a junction 240 to form the disinfection outlet 230. The disinfection outlet 230 includes the junction 470 from the bypass line 420. Rather than two independent water supplies being combined downstream of the disinfection unit 400, as seen in Figures 3 and 7, in this embodiment the first and second water supplies are combined internal to the disinfection unit 402.

The disinfection cartridges 450 and dilution line disinfection cartridges 1450 are substantially the same structure, e.g. both comprise a medium including a releasable biocidal species (“biocide”) that is released into water coming into contact with the medium. The primary difference between the disinfection cartridge(s) 450 and the dilution line disinfection cartridge(s) 1450 is the concentration of biocidal species (e.g. bromine) which is bound to the medium (e.g. loaded or dosed into the medium) when each cartridge is installed and/or when each cartridge is replenished during use of the disinfection unit 402.

For any of the disinfection cartridges 450, 1450, the cartridge medium (e.g. the halogenated polystyrenehydantoin resin beads) is prepared by reacting a precursor to the medium (e.g. the non-halogenated polystyrenehydantoin resin beads) with a solution of the free biocide of a known concentration such that the biocidal species is loaded into the medium. It will be appreciated that the concentration of the biocidal species within the medium may be controlled e.g. by one of more of: changing the concentration of the solution containing the free biocide, changing the mass of precursor medium that is placed in contact with the free biocide solution, altering the duration of time the precursor medium is in contact with the free biocide solution, or other reaction conditions (e.g. agitation, temperature, pressure, etc.).

The concentration of the biocidal species within the medium will thus increase as the amount of bromine (releasably) bound to the medium increases. It will be appreciated that the medium will have a finite number of binding sites to which the free biocide (e.g. bromine) may bind, and thus, the medium will be “fully” charged or loaded when substantially all binding sites have reacted to bind to a biocidal species. Similarly, if only 50% of the available binding sites have reacted to bind to a biocidal species, the medium may be considered to be “half’ charged or loaded.

For embodiments of which utilise a system of internal dilution (e.g. a Disinfection unit 402 that comprises at least one dilution line disinfection cartridge 1450 in the dilution line 215), the concentration of biocidal species in the medium within the dilution line disinfection cartridge(s) 1450 is less than the concentration of biocidal species in the medium within the disinfection cartridge(s) 450 when the cartridges 450, 1450 are installed (or replenished).

For example, in some embodiments, upon installation the concentration of biocidal species in the medium of the disinfection cartridge(s) 450 is selected to be about 32 wt% with an initial concentration of residual bromine in the water coming into contact with the medium of about 10 ppm. Such disinfection cartridge(s) 450 may be determined to have come to the end of their lifetime (e.g. are needing to be replaced) when the concentration of biocidal species in the medium of the disinfection cartridge(s) 450 falls below 20 wt% (e.g. resulting in a concentration of residual bromine in the water of about 0.5 ppm). In contrast, upon installation the concentration of biocidal species in the medium of the dilution disinfection cartridge(s) 1450 is selected to be 20 wt% with an initial concentration of residual bromine in the water coming into contact with the medium of about 0.5 ppm. Such dilution disinfection cartridge(s) 1450 may be determined to have come to the end of their lifetime (e.g. are needing to be replaced) when the concentration of biocidal species in the medium of the dilution disinfection cartridge(s) falls below about 7 wt% (e.g. resulting in a concentration of residual bromine in the water of about 0.1 ppm).

For example, if the concentration of loaded biocidal species in a disinfection cartridge 450 is 10 times greater than the concentration of loaded biocidal species in a dilution line disinfection cartridge 1450, and if the same volume of water passes through the cartridges 450, 1450 at the same flow rate, it will be appreciated that the concentration of biocidal species that is released from the disinfection cartridge 450 will be 10 times greater than the concentration of biocidal species released from the dilution line disinfection cartridge 1450 such that, upon combination at junction 240, the concentration of biocidal species output from the Disinfection unit 402 by the disinfection outlet 230 will be an average of the two concentrations, i.e. about half or 55% of the concentration released the disinfection cartridge 450.

Figure 12 shows an embodiment of the present invention wherein the Disinfection unit 402 includes two disinfection cartridges 450a and 450b and two dilution line disinfection cartridges 1450a and 1450b which are all arranged in parallel. An optional pre-treatment unit 110 is connected upstream of the Disinfection unit 402, and a junction 120 allows the main input line 105, 115 to split off into a dosing water line 140 that feeds an optional dosing system 300. The pre-treatment unit 110 and dosing system 300 may be the same as already described with reference to Figures 5-6. The components of the Disinfection unit 402 are generally the same as already described in relation to Figure 11.

Figure 12 shows that the Disinfection unit 402 outputs clean (e.g. disinfected) drinking water comprising residual biocidal species via the disinfection outlet 230, which is then optionally directed through a “balance” tank 1000 before reaching an output line 260 which provides drinking water to the drinking line 135 to be consumed by poultry 150 (or other animals). The use of a “balance” tank 1000 will be described later with reference to Figures 14-18.

Figure 13 shows a block diagram of the apparatus used to control an embodiment of the water treatment system 100, 102 which utilises the Disinfection System 202 and Disinfection unit 402 as shown in Figures 10 and 11. A controller 702 is configured to receive flow measurements from the flow meters 225, 1225 and to output control signals to the control valves 490, 495, 425, 445n and 1250n in the Disinfection unit 402. As compared with Figure 8, it can be seen that the flow meters 225, 1225 are now internal to the Disinfection unit 402. It will be appreciated that controller 700 and controller 702 a substantially very similar with many identical functionalities and components. Thus, the below discussion will primarily focus on the different functions of controller 702 compared to controller 700 which are specific to the working of Disinfection System 202 in relation to achieving dilution using a dilution line internal to the Disinfection unit 402.

The system 100, 102 may be operated in accordance with a series of pre-programmed instructions stored in the memory of the controller 702. The controller 702 executes the operations by communicating with the system apparatus where the communication may be either wired or wireless (e.g. via a network). In some embodiments the operations may be carried out at a predetermined frequency or in response to sensor data received by the controller 702, such as data communicated to the controller 702 from the flow meters 125, 225 and 1225, or other sensors 720 such as a sensor used to detect the concentration of the biocidal species in the water.

As with the controller 700, once the controller 702 determines the operation to be performed by the system, the controller 702 executes the operation by sending a signal (e.g. an electrical signal) to the plurality of control valves within the system which are used to control the flow of water through the system.

The controller 702 may also output data relating to the operational conditions of the system to user display 730. For example, the concentration data of the disinfectant detected by concentration sensor 720 and/or the flow meter data from flow meters 125, 225 and 1225 may be displayed and used by a user to determine whether the system is functioning abnormally, e.g. a drop in flow rate may indicate a blockage such that the user may manually input that the system perform a bypass cycle.

Although not discussed here, it will be appreciated that the Disinfection System 202 and Disinfection unit 402 of system 100, 102 may, in an analogous manor to Disinfection System 200 and Disinfection unit 400, be either activated or deactivated depending on the required operation by the opening or closing of the valves controlled by the controller 702. Furthermore, if the units are active they may operate in at least two different modes: “normal mode” or “bypass mode”. The method of operating the system 100, 102 in “normal mode” will now be described in relation to Figures 12 and 13. It will be appreciated that although Figure 12 does not show the valves and bypass lines for operating the system in “bypass mode” the embodiments described above in relation to Figure 7 may be applied to this embodiment. Operation of the water treatment system seen in Figures 11 and 12 will now be described with reference also to Figure 13.

Raw water enters the pre-treatment unit 110 via a main linel 05 where the water is directed into a pre-treatment filter 530. The pre-treatment filter 530 outputs pre-treated water which may then be provided to a second filter 1200 (e.g. a fine particle filter for removal of any course particulates in the fluid). Pressure gauges 1205, 1210 may be provided either side of the pre-treatment filter 530 to provide an input to controller 702 regarding changes in pressure across the pre-treatment filter 530.

Water output from the pre-treatment unit 110 passes along the water inlet 115 to a junction 120 where at least a portion of the water supply is optionally directed into dosing water line 140. Water which is not directed to the dosing water line 140 passes through junction 120 into the Disinfection unit 402 of the Disinfection System 202 via disinfection input 220. The Disinfection unit 402 shown in Figure 12 comprises two disinfection cartridges 450a, 450b and two dilution line disinfection cartridges 1450a, 1450b arranged in parallel. In preferable embodiments, the disinfection cartridges 450n, 1450n are selected to be HaloPure™ cartridges containing brominated polystyrene hydantoin beads.

In preferable embodiments the concentration of biocidal species in the medium within the dilution line disinfection cartridges 1450a, 1450b is less than (e.g. substantially less than) the concentration of biocidal species in the medium within the disinfection cartridges 450a, 450b, at least upon installation of the Disinfection unit 402.

To control the concentration of biocidal species in water output from the Disinfection unit 402, the Disinfection unit 402 is configured such that the number of disinfection cartridges 450n, 1450n available at any one time to the disinfection input 220 may be controlled by the controller 702. Furthermore, the controller 702 may ensure that each disinfection cartridge 450a, 450b, 1450a, 1450b is depleted of its biocidal species in an even and coordinated manner.

For example, when the release of biocidal species from the medium in the disinfection cartridge is expected to be relatively high (e.g. at early times and low water volumes), the controller 702 will configure the system such that it operates in a one-cartridge cycle. In a one-cartridge cycle, only one disinfection cartridge 450a, 450b and one dilution line disinfection cartridge 1450a, 1450b is available for water to pass through, e.g. the controller 702 configures the system such that control valves 445a and 1250a are open and control valves 445b and 1250b are closed. Thus, in contrast to the description above, in a 1,1- cartridge cycle of the Disinfection unit 402, two disinfection cartridges (one dilution line disinfection cartridge 1450 and one disinfection cartridge 450) are active.

The controller 702 monitors the flow rate of water input to the disinfection cartridges 450n, 1450n via the flow meters 225n and 1225n such that, in a 1,1 -cartridge cycle for example, the total volume of water that has passed through disinfection cartridge 450a and dilution line disinfection cartridge 1450a may be monitored. When the volume of water that has passed through disinfection cartridge 450a is determined to have exceeded the pre-determined threshold level for a 1,1 -cartridge cycle in that phase, the controller 702 closes control valve 445a and opens control valve 445b such that the water at the disinfection inlet 220 is now directed through cartridge 450b and the process is repeated. Similarly, when the volume of water that has passed through dilution line disinfection cartridge 1450a is determined to have exceeded the pre-determined threshold level for a 1,1 -cartridge cycle in that phase, the controller 702 closes control valve 1250a and opens control valve 1250b such that the water at the disinfection inlet 220 is now directed through cartridge 1450b and the process is repeated. It will be appreciated that the pre-determined threshold level for an n,m-cycle transition for disinfection cartridges 450n and dilution line disinfection cartridges 1450n may be the same value, or may be a different value.

Furthermore, it will be appreciated that n and m may be the same value (e.g. in a 1,1 -cycle both the dilution line disinfection cartridges 1450n and the disinfection cartridges 450n are in a one-cartridge cycle) or alternatively, n and m may have different integer values (e.g. in 1,3- cycle the disinfection cartridges 450 are in a one-cartridge cycle but the dilution line disinfection cartridges are in a three-cartridge cycle), where n is the cycle number for the disinfection cartridges 450 in the disinfection line 1220 and m is the cycle number for the disinfection cartridges 1450 in the dilution line 1215.

As described above, in-spite of the n,m-cartridge cycle operation control, the concentration of biocidal species (e.g. bromine) from the disinfection cartridges 450n may exceed desirable levels such that dilution is required to fine tune the biocide levels, which arises before the water outputs the Disinfection unit 402 in this embodiment.

For example, as described above, at an early stage in the lifetime of a disinfection cartridge 450n following installation, the release of biocidal species from the medium may be higher than is desirable and thus the controller 702 may determine (through pre-set programming and/or the flowmeter 225 and 1225 data) that the concentration needs to be diluted by m times, e.g. 6 times.

Example 4 - Internal dilution control

To effect the required dilution, the controller 702 may, using flow meters 225n and 1225n, configure the control valves 445n and 1250n to change the relative volumes of water that pass through the disinfection cartridges 450n relative to the dilution line disinfection cartridges 1450n. In some embodiments, the controller 702 may activate more dilution line disinfection cartridges 1450n to effect a greater dilution. For example, if the controller 702 transitioned the system from a 1,1 -cycle to a 1,2-cycle the dilution ratio would increase by 2 (e.g. the concentration of the biocidal species output from the Disinfection unit 402 in a 1 ,2- cycle would be half that of the concentration output from the Disinfection unit 402 in a 1,1- cycle under the same conditions).

Alternatively, or in addition to changing the number of disinfection cartridges 450n, 1450n that are active (and thus the n,m-cycle) the relative flow rate of water through the dilution line 1215 with respect to the disinfection line 1220 may be altered by adjusting the control valves 445n and 1250n. The control valves 445n and 1250n are preferably regulating valves that can be operated to provide a variable flow rate through the valve. For example, with regard to Figure 12, if the Disinfection unit 402 is running in a 1,1 -cycle with both control valves 445a and 1250a open fully, e.g. 100% (and control valves 445b and 1250b closed, e.g. 0%) then, if controller 702 configures control valve 445a to change to being only 25% open, the flow rate and thus volume of water flowing through the disinfection cartridge 450a will decrease by 75% and thus the average concentration of the biocidal species output from the Disinfection unit 402 will decrease according to a non-linear polynomial relationship.

It will therefore be appreciated that a procedure (e.g. comprising phases and sub-phases) very similar to that described above in relation to the operation of Disinfection System 200 may be used by controller 702 to control Disinfection System 202 using the data from flow meters 225 and 1225 to determine the relative flow rate through the dilution line(s) 1215 and disinfection line(s) 1220 of the Disinfection unit 402. In some embodiments, the schedule may be pre-programmed into the controller 702 such that the controller 702 receives data from the flow meters 225n and 1225n at pre-defined intervals (e.g. every 5 minutes) and determines the total volume of water that has passed through the Disinfection unit 402 as well as the relative flow rate to determine the necessary phase and configuration settings of the control valves 445n and 1250n. In some embodiments, the controller 702 may determine the sub-phase using only Total Volume data from a flow meters 125 (e.g. positioned upstream of the Disinfection System 202 as seen in Figure 1). In other embodiments, the sub-phase may be determined by comparing the Total Volume to a reference profile, e.g. a profile that plots the concentration of released biocidal species as a function of the total volume. In some embodiments, the sub-phase may be determined by predicting the amount of time the system will spend in a phase and/or the total volume of the phase and dividing the phase up into equal segments. In some embodiments, the sub-phase may be determined in- situ using concentration data received by the controller 702 from at least one concentration sensor 720 which can be compared to a predetermined concentration profile.

Once the controller 702 has determined the phase and sub-phase, the controller 702 may then configure the system to achieve the desired concentration by setting the required number of disinfection cartridges 450n and 1450n to be used (e.g. the n,m-cartridge cycle) and/or the positions of the control valves 445n and 1250n.

In some further embodiments the internal dilution approach described in relation to Figures 10-13 may be combined with either of the external dilution approaches described in relation to Figures 3-8. For example, T able 1 , T able 2 or T able 3 may be applied to set a schedule for external dilution control in addition to implementing a disinfection unit in which the concentration of biocidal species in the medium within some of the cartridges is less than the concentration of biocidal species in the medium within some other disinfection cartridges when the cartridges are installed (or replenished). For example, an internal dilution approach may be sufficient on its own to adjust the biocide concentration for relatively low water volumes and/or flow rates, but one or more external dilution lines may be added for a water treatment system designed to handle relatively high water volumes and/or flow rates.

Introduction to Biocide Balancing

As has been discussed in detail above, it is desirable to control the concentration of biocidal species (e.g. bromine) released by the disinfection cartridges (e.g. HaloPure™ cartridges) such that the biocide concentration is at an efficacious level to inactivate pathogens and reduce biofilm formation downstream of the treatment system (e.g. a biocide concentration above 0.5 ppm, or above 0.3 ppm, for residual bromine), whilst maximising cartridge lifetime by minimising unnecessary depletion.

Thus far it has been described with reference to Examples 1-4 how embodiments of the present invention may achieve this aim by use of a controller 700, 702 to configure the Disinfection Unit 400, 402 to operate in an n-cartridge cycle and/or by diluting the output of the Disinfection System 200, 202 e.g. by configuring at least some of the control valves 250n, 1250n, 425 and 445n to effect a pre-set or target dilution ratio. As discussed in detail above, the dilution ratio may either be determined periodically in situ and compared to a target dilution ratio to provide an advanced feedback to the system (Examples 3 and 4) or the dilution ratio may be pre-set i.e. determined by the controller 700, 702 based on preprogrammed values stored within the controller 700, 702 memory based on release profile of the biocidal species from the medium as a function of the total volume of fluid passing through the Disinfection unit 400, 402 (see Example 2).

However, it will be appreciated that, in systems where the dilution line 215 is provided externally to the Disinfection unit 400 (e.g. as described in Figure 3 above), the volume of water being used to dilute the water output from the Disinfection Unit 400 will be entirely nondisinfected and thus potentially containing harmful pathogens and biofilms. Furthermore, it will be appreciated that when the biocidal release from the medium of the disinfection cartridges 450 is large (e.g. during an early stage in the system lifetime) the dilution ratio may be high and thus the volume of non-disinfected water combined with the disinfected water via the dilution line(s) 215 may be significant.

Furthermore, it will be appreciated that, in-spite of the advanced control described above to adjust the concentration of biocide output from Disinfection System 200, 202 (e.g. using external and/or internal dilution approaches), the concentration of biocide (e.g. bromine) released into the water will fluctuate within any given determined phase or sub-phase of the controller program. This will result in a tolerance level or error of the biocide concentration in the water supply at the point of consumption.

It will be appreciated that the tolerance level or error range in the biocide concentration will be narrower for the more sophisticated in situ feedback embodiments described herein (e.g. Examples 3-4) as compared to the embodiments that rely on predictions based on model data profiles as a function of total volume (e.g. Examples 1-2). However, in some circumstances, the increase in cost associated with the more advanced system of control may not be outweighed by the improvement in tolerance of the biocide concentration. Thus, in some circumstances, e.g. in relatively small systems (e.g. smaller farms), a reasonably large tolerance range may be considered acceptable.

In some circumstances, the tolerance level associated with the basic dilution control approach may be too large to be desirable yet not significant enough to outweigh the increased cost of the advanced dilution control approach. Thus is may be desirable to reduce the tolerance level of the biocide concentration released into the water supply without implementation of the more sophisticated (and higher cost) system. Alternatively, it may be appreciated that even the tolerance level obtainable by the more advanced dilution control approach may remain too large for some circumstances and/or systems and thus an additional concentration control is desirable to improve and moderate the fluctuation in biocide concentration.

Example 5 - Balancing of biocide concentration

Figure 14 shows an example arrangement of how a Balance Tank 1000 may be incorporated into the Disinfection System 200 already described above. Water entering the Disinfection System 200 through the water inlet line 130 is split at dilution line input junction 210 such that a second water supply is provided into the dilution line 215 in addition to the first water supply carried by the disinfection line 220. The disinfected water output from the Disinfection Unit 400, 402 via the disinfection outlet 230 is recombined with the water supply from the dilution line 215 at the junction 240 to form the output line 260. Thus, at this point the biocidal species concentration of the water that passes through the Disinfection Unit 400, 402 is diluted by the non-disinfected water from the dilution line 215 by a dilution ratio determined by the configuration of the control valve 250 at least.

Figure 14 depicts how, in some embodiments, the disinfected and diluted water carried by the output line 260 enters a Balance Tank 1000. As well as serving the purpose of moderating the tolerance level of the biocide concentration of the Disinfection System 400, 402 (as will be described below), the Balance Tank 1000 additionally provides a holding body for the water carried by the output line 260 to adequately mix before being passed downstream to the drinking line 135.

In some embodiments, as shown in Figure 7, the combination junction 240 comprises the Balance Tank 1000 such that the disinfected water that is output from the Treatment Unit 400, 402 and the non-disinfected water from the dilution line 215 are input to the Balance Tank 1000 via independent inlets, e.g. the Balance Tank 1000 includes two inlets, one inlet arranged to bring the first water supply from the disinfection system 200, 202 to the balance tank 1000 and a second inlet arranged to bring the second water supply from the dilution line 215 to the balance tank 1000. In some embodiments, the Balance Tank 1000 may comprise any suitable or desirable number of inlets. For example, in a system comprising a plurality of dilution lines 215a, 215b, each dilution line 215a, 215b may be arranged to independently bring water to the balance tank without first converging the dilution lines 215a, 215b into one single line. Such an embodiment is represented in Figure 7. Similarly, it may be envisaged that each disinfection cartridge of the disinfection system 200, 202 may output fluid into an independent line that is arranged to bring water to the balance tank without first converging into a single line, e.g. without the junctions 460n seen in Figures 4 and 7.

The Balance Tank 1000 comprises a second medium which is capable of reversibly binding with the biocidal species released into the first water supply when passing through the disinfection cartridges 450n, 1450n of the Disinfection Unit 400, 402. It will thus be appreciated that, as the second medium in the Balance Tank 1000 reversibly binds to the biocidal species, the medium is capable of both absorbing (e.g. any biocidal species present in the water to which the medium comes in contact) and releasing biocidal species (e.g. pre- loaded or dosed into the medium upon installation or alternatively had been previously absorbed from the water supply passing through the Balance Tank).

In some embodiments, the Balance Tank 1000 is substantially the same structure as the disinfection cartridges 450n, 1450n. In some embodiments, the biocidal species and/or second medium of the Balance Tank 1000 is selected to be the same as the biocidal species and/or first medium in the disinfection cartridges 450n, 1450n. The Balance Tank 1000 may therefore comprise a second medium including releasable oxidative bromine, e.g. comprising one or more HaloPure™ cartridges containing brominated polystyrene hydantoin beads.

To prepare the medium for inclusion within the Balance Tank 1000 and the disinfection cartridges 450n, 1450n (e.g. the halogenated polystyrenehydantoin resin beads), a precursor to the medium (e.g. the non-halogenated polystyrenehydantoin resin beads) is reacted with a solution of the free biocide such that the biocidal species is loaded into the medium. It will be appreciated that the concentration of the biocidal species (“biocide”) within the medium may be controlled e.g. by one or more of: changing the concentration of the solution containing the free biocide, changing the mass of precursor medium that is placed in contact with the free biocide solution, and altering the duration of time the precursor medium is in contact with the free biocide solution, or other reaction conditions (e.g. agitation, temperature, pressure, etc.). When the disinfection cartridges 450n, 1450n are installed in the Disinfection unit 400, 402, it is desirable that the first medium (e.g. the halogenated polystyrenehydantoin resin beads) is substantially fully loaded or charged (e.g. the concentration of the biocidal species in the medium is at a maximum value) such that the released biocide concentration is at its highest value when water first flows through the system. As the total water volume increases, the release of the biocidal species decreases (as shown in Figure 9b) as the medium becomes increasingly discharged (as shown in Figure 9a).

In contrast to the disinfection cartridges 450n, 1450n, it is desirable that the second medium within the Balance Tank 1000 is only partially charged or loaded when installed within the system 100, 102. Instead, it is desirable for the medium within the Balance Tank 1000 to be selectively charged to a pre-set concentration such that the biocide concentration released from the Balance Tank 1000 when water flows through the tank equals the desired biocide concentration for the water supply to the point of consumption (e.g. drinking line 135). For example, when the biocide is selected to be bromine, the precursor medium for use within the Balance Tank 1000 may be loaded with bromine such that the concentration of bromine released from the medium in the Balance Tank 1000 is no greater than 1 ppm or 1.5 ppm, e.g. between 0.3 and 2 ppm, e.g. between 0.5 and 1 ppm, or between 0.5 and 1.5 ppm.

By only partially charging the second medium within the Balance Tank 1000 it will be appreciated that the medium (e.g. halogenated polystyrenehydantoin resin beads) will have a plurality of vacant binding positions which are available to reversibly bind with i.e. absorb the biocidal species present in the water that comes into contact with the medium after installation.

For example, when the contact medium is selected to be a halogenated polystyrenehydantoin resin bead, the biocidal halogen is bound to the amide and imide nitrogen groups of the beads. Thus, when the beads are not fully charged (e.g. not all nitrogen groups bound to a halogen), there will be a plurality of vacant nitrogens which may bind to any halogen present in water that is brought in contact with the beads.

Returning to Figure 14, it will be appreciated that the biocide concentration of the water output from the junction 240 into the output line 260 has a certain (and fluctuating) concentration of biocidal species. Thus, the Balance Tank 1000 acts as both a biocidal species reservoir (e.g. releasing additional biocidal species into the water when the concentration of the biocidal species in the output line 260 is lower than the pre-set desirable concentration) and a biocidal species sink (e.g. absorbing biocidal species from the water input to the Balance Tank 1000 to reduce the concentration of biocidal species within the water whilst simultaneously increasing the extent that the second medium within the Balance Tank 1000 is charged).

Figure 15 schematically represents how the concentration of biocidal species in the water changes after passing through the balance tank 1000, as well as how the bound concentration of biocidal species bound to the second medium of the balance tank 1000 changes after water has passed through under three different scenarios. In Figure 15 (as well as Figure 17 described below), the thickness of the horizontal lines inside the Balance Tank 1000a, 1000b, 1000c at a given moment in time represents the bound concentration of biocidal species (e.g. a thicker line represents a greater concentration) bound to the Balance tank 1000 medium. Similarly, the thickness of the arrows represent the concentration of biocidal species within the water input to the balance tank 1000 (e.g. via line 260a, 260b, 260c) as well as output from the balance tank 1000 (e.g. via line 1010a, 1010b, 1010c). For example, the input arrow 260a is schematically represented by a thicker arrow than the arrow representing line 260b which indicates that the concentration of the biocidal species within the water in line 260a is higher than the concentration of the biocidal species within the water in line 260b. In turn, the change in the thickness (e.g. gradation in thickness) of lines shown in the Balance Tank 1000a shows that the bound concentration of biocidal species is increasing across Balance Tank 1000a (e.g. biocidal species present in the water passing through the Balance Tank 1000a are being absorbed such that the bound concentration of biocidal species increases).

Figure 15a shows a situation where the biocide concentration of the water input to the Balance Tank 1000a via line 260a is higher than the bound concentration of the biocidal species within the second medium of the Balance Tank 1000a (e.g. selected by the extent of charging or dosing). As such, the vacant positions of the medium contained within Balance Tank 1000a will absorb (e.g. bind to) from the water more biocidal species than is simultaneously released from the medium positions which have a biocidal species reversibly bound, resulting in the bound concentration of biocidal species within the medium of the Balance Tank 1000a increasing (e.g. the medium becomes increasingly charged with biocidal species over time). This increase in the bound concentration of biocidal species in the Balance Tank 1000a is schematically represented by a transition to thicker lines across the Balance Tank 1000a from line 260a to the tank outlet 1010a (e.g. an increase in concentration over time). As the rate of uptake of biocidal species from the water entering the Balance Tank 1000a via the line 260a exceeds the rate at which the medium of the Balance Tank 1000a releases biocidal species from the charged sites of the medium (e.g. occupied positions which are reversibly bound to a biocidal species) within Balance Tank 1000a, the concentration of the biocidal species in the water output from the Balance Tank 1000a into line 1010a is reduced compared to the concentration of the biocidal species input into the Balance Tank 1000a via line 260a (shown schematically by 260a being represented as a thicker line than 1010a).

Figure 15c shows the situation where the biocide concentration input to the Balance Tank 1000c is lower that the bound concentration of biocidal species in the second medium of the Balance Tank 1000c (e.g. selected by the extent of charging or dosing), meaning that the medium within the Balance Tank 1000c will release (e.g. from occupied positions where a biocidal species is bound) more biocidal species than is absorbed from the water input to the Balance Tank 1000c (e.g. at vacant positions capable of binding to biocidal species). This results in the bound concentration of biocidal species in the Balance Tank 1000c decreasing as the medium is discharged. Thus the Balance Tank 1000c is depicted with a gradient transitioning to thinner lines from 260c to outlet 1010c (e.g. reducing in concentration with respect to time).

As such, the rate of release of biocidal species from the medium within the Balance Tank 1000c exceeds the rate of absorption of biocidal species from the water input into Balance Tank 1000c, and thus the concentration of the biocidal species in the water output from the Balance Tank 1000c into line 1010c is increased compared to the concentration of the biocidal species input into the Balance Tank 1000c via line 260c (shown schematically by 260c being depicted in a thinner line than 1010c).

Figure 15b shows the situation in which the biocide concentration input to the Balance Tank 1000b via line 260b is the same as the bound concentration of the Balance Tank 1000b (e.g. between 0.3 ppm and 2 ppm, e.g. between 0.5 ppm to 1 ppm of bromine). As such, the medium within the Balance Tank 1000b will release (e.g. from occupied positions where a biocidal species is bound of the biocidal medium) and absorb (e.g. from the fluid input to the Balance Tank 1000b via line 260b) biocidal species at the same rate. As such, the bound concentration of biocidal species does not change with respect to time across Balance Tank 1000b (shown by the thickness of lines remaining constant across the Balance Tank from 260b to outlet 1010b) and the concentration of biocidal species in the water output from the Balance Tank 1000c via line 1010c is the same as the biocidal species concentration of the water input to the Balance Tank 1010c via line 260c. In light of the foregoing, it will thus be appreciated that the concentration of the biocidal species bound to the medium within the Balance T ank 1000 will vary with respect to the volume of fluid that has passed through the disinfection system 200.

Figure 16 shows the change in concentration of the biocidal species in the water released from the Disinfection Unit 400, 402 (trace 1210) i.e. prior to dilution and the change in concentration of bound biocidal species in the Balance Tank 1000 (trace 1220) as a function of the total volume of water passing through the system 100, 102. For simplification purposes it is assumed that the dilution ratio is constant over the time period shown and that there is no change in cartridge cycle (e.g. the same cartridge(s) are active for the entire time period shown).

The Balance Tank 1000 is installed into the system 100, 102 with a pre-set bound concentration of biocidal species within the second medium chosen such that, upon initial contact with water absent any biocidal species (e.g. substantially null concentration of biocidal species) the concentration of biocidal species released from the second medium into the water would be at a desired concentration (e.g. for consumption) to ensure that the concentration of biocidal species in the water output from the Balance Tank 1000 is at the desired level e.g. about 1 ppm (so as to ensure a concentration of 1 ppm or less at the point of consumption). This desired concentration of biocidal species in the water output from the system 100, 102 is represented on Figure 16 by the horizontal dashed line 1230.

With reference to Figure 17a, at early times (e.g. point A in Figure 16) (e.g. when a low total volume of water has passed through the system 100, 102) water is input into the Disinfection unit 400a, 402a via disinfection inlet 220a and biocidal species are released into the water resulting in a high concentration of biocidal species in the water being output from the Disinfection unit 400a, 402a via outlet line 230a. The disinfected water then enters the Balance Tank 1000a via inlet 260a and the medium in the Balance Tank 1000a acts to effect a net absorption of biocidal species from the water input to the Balance Tank 1000a (e.g. the rate of absorption of biocidal species by the medium exceeds the rate of release of biocidal species from the medium). As a result, the concentration of biocide in the water output from the Balance Tank 1000a via outlet 1010a is reduced (e.g. to the desired pre-set concentration) compared to the concentration of biocide of the disinfected water input to the Balance Tank 1000a via inlet 260a. As such, the bound concentration of biocidal species within the medium of the Balance Tank 1000 increases when the concentration of biocidal species released into the water from the Disinfection unit 400a, 402a is higher than desired. The Balance Tank 1000a may therefore be considered to be acting as a sink for the excess biocidal species.

With reference to Figure 17b, as the concentration of the biocidal species released into the water from the Disinfection Unit 400b, 402b reaches the desired pre-set concentration (point B in Figure 16), the change in the bound concentration of the biocidal species in the medium within the Balance Tank 1000b becomes less significant as the rate of release of biocidal species begins to match the rate of absorption. As such, the concentration of the biocidal species bound to the medium in the Balance tank 1000b remains substantially constant.

With reference to Figure 17c, when the concentration of the biocidal species released into the water from the disinfection cartridge(s) in the Disinfection Unit 400c, 402c falls below the desired pre-set concentration for effective disinfection 1230 (e.g. point C in Figure 16) biocidal species are released from the medium in the Balance Tank 1000c to increase the concentration of the biocidal species in the water passing through the Balance Tank 1000c. As such, the biocidal species concentration in the water input to the Balance Tank 1000c via inlet 260c is less than the concentration of biocidal species in the water output from the Balance Tank 1000c via outlet 1010c, and the Balance tank is effectively acting as a biocidal species reservoir to increase the concentration of biocidal species compared to that released from the Disinfection Unit 400c, 402c.

With reference to Figure 17d, eventually, a sufficient volume of water will have passed through the system 100, 102 such that the bound concentration of biocidal species in the medium in the Balance Tank 1000d will be depleted and the rate of release of biocidal species from the medium within the balance tank is too slow to be able to effect the desired concentration (see point D).

For example, Table 4 (below) shows a numerical example of the change in concentration of Bromine, [Br]_y, with respect to time points A to D (discussed above in relation to Figure 16) at various components along the system, where y is the reference numeral used in Figures 12 and 13 to denote that component, e.g. [Br]26o is the bromine concentration in line 260 and thus the concentration of bromine output from the Disinfection System 200, 202. The concentrations used to populate this table are simplified and exaggerated for exemplary purposes, the numbers therein are not intended to be limiting in any respect. Table 4: change in concentration of Bromine [Br]_y across Balance Tank 1000

It will be appreciated that the Balance Tank 1000 may be combined with any suitable and/or desirable embodiment of the invention disclosed herein. For example, in embodiments which utilise the basic dilution control (e.g. Example 2), it will be appreciated that each phase will define a configuration of the system to effect the desired average concentration of biocidal species in the water. However, across said phase it will be appreciated that there will be a variation whereby it may be expected that the concentration of biocidal species released into the water at early points in the phase will be greater than that defined at the end of the same phase. As such, in such systems the Balance Tank 1000 acts to absorb biocidal species from the water at early points in the phase and release biocidal species at later points in the phase, whilst in turn the water passing through the balance tank acts to charge the medium of the balance tank 1000 (e.g. increase the bound concentration of biocidal species in the medium) at early points in a phase and dis-charge the medium of the balance tank 1000 (e.g. reduce the bound concentration of biocidal species in the medium) at later points in the same phase. As such, it will be appreciated that the balance tank 1000 may cycle through the scenarios shown in Figures 17a to 17d a plurality of times in the lifetime of the system 100, 102.

Example 6 - Disinfection cartridges in series

In one or more examples it may be desirable to arrange a plurality of disinfection cartridges in series so as to increase the concentration of the biocidal species released for the same volume of water treated. However, each disinfection cartridge results in a pressure drop in the water supply as it passes through the disinfection unit and this may limit the number of disinfection cartridges that can be tolerated to be arranged in series.

Figure 18 shows an exemplary embodiment of system 100, 102 that may be configured to operate via any suitable embodiment disclosed herein. The disinfection system 200 shown in Figure 18 includes four disinfection cartridges 450 arranged in two parallel disinfection lines (e.g. the four disinfection cartridges 450 are in a parallel arrangement comprising two pairs of serially arranged cartridges). Each disinfection line comprises a control valve 445 which may be either an on/off valve or a regulating valve. The flow of water into the disinfection lines is controlled by a regulating valve 425. The output from the disinfection cartridges 450 is combined with the dilution line 215 before the diluted water supply enters the balance tank 1000. Thus, it will be appreciated that dilution control may be effected and controlled by any suitable and/or desirable combination of systems and/or controller embodiments described above using at least valves 250, 425 and 445.

Although the four disinfection cartridges 450 shown in Figure 18 are represented, as described above, as all being disinfection cartridges 450n (e.g. comprising the same bound concentration of biocidal species upon installation), it will be appreciated that the same structure may similarly be used to effect internal dilution without structural modification by configuring one of the disinfection lines to be a dilution line comprising dilution cartridges 1450n with a lower bound concentration of biocidal species in the medium than the disinfection cartridges 450n. Valves 445 (and 1445) may then exclusively (in combination with the balance tank) control the dilution in such embodiments such that valve 250 (as labelled in Figure 18) controls the flow through a bypass line.

Example 7 - Backwash

It will be appreciated that in some circumstances it may be desirable to operate the water treatment system 100, 102 of any embodiment described above in a “backwash mode”. For example, it may be desirable to backwash water through the filters and/or disinfection cartridges to reverse any compaction of the medium contained therewithin by the pressure of the water flowing through the filter and/or disinfection cartridges during normal operation.

To perform a backwash cycle of the Disinfection Unit 400 seen in Figure 7, the controller 700 configures the bypass valve 490 and the exhaust valve 495 to be open, and the disinfection control valve 425 and disinfection outlet valve 480 to be closed. Water input to the Disinfection System 200 thus flows into the bypass line 420 via junction 410. Due to the disinfection outlet valve 480 being closed, the water output from bypass line 420 is directed into the disinfection outlet line 465 in a reverse direction via the output junction 470. The water thus flows backwards towards the disinfection line 415 through all of the branches where the cartridge control valves 445a-445f are configured to be open. In some embodiments all the valves 445a-445f may be configured to be open at the same time. In alternative embodiments the cartridge control valves 445a to 445f may be sequentially opened by the controller 700 such that only one cartridge 450n is backwashed at any one time. It will be appreciated that this may be desirable, for example when it is known that a blockage is present only in branch line 440a or cartridge 450a and thus flowing water through the other cartridges 450b to 450f would result in disinfectant being unnecessarily depleted in these cartridges. Once the water has flowed through the open branches and has entered the disinfection line 415 it is directed, by virtue of the valve 425 being closed, through the exhaust valve 495 and out of the system 100, 102 via the waste output line 500.

Although the “backwash mode” has only been described above in relation to the Disinfection Unit 400 of Figure 7, it will be appreciated that the same principle of operation may be applied to any of the units of the various water treatment systems 100, 102 described herein. Furthermore, it will be appreciated that each unit may be independently configured by the controller 700 such that the system operates in any suitable or desirable combination of unit modes. For example, the Dosing System 300 may be configured to be in backwash mode whilst the Disinfection System 200 operates in normal mode.

Claims

1 . A method of disinfecting water for animal consumption, the method comprising: arranging a first water supply to pass through a water treatment system, the system comprising: a disinfection inlet arranged to bring a first water supply to a disinfection unit; the disinfection unit comprising a number n (n>1) of water disinfection cartridges, wherein each water disinfection cartridge comprises a first polymeric medium including a releasable biocidal halogen species that is released into the first water supply coming into contact with the first polymeric medium to provide a disinfected water supply, wherein the disinfected water supply has a first concentration of the biocidal halogen species; a balance tank inlet arranged to bring the disinfected water supply to a balance tank; the balance tank comprising a second polymeric medium including: the releasable biocidal halogen species, arranged to be available to be released at a release rate into the disinfected water supply coming into contact with the second polymeric medium; and vacant binding sites, arranged to reversibly bind at an absorption rate with the biocidal halogen species in the disinfected water supply coming into contact with the second polymeric medium; wherein a ratio of the absorption rate to the release rate defines a rate ratio of the second polymeric medium; and wherein the rate ratio of the second polymeric medium determines an adjustment effect that the balance tank has on the first concentration of biocidal halogen species in the disinfected water supply to achieve a second concentration of the biocidal halogen species in a balanced water supply output from the balance tank; the method comprising: arranging the first water supply to pass through the disinfection cartridges to provide the disinfection water supply; and arranging the disinfection water supply to pass through the balance tank to provide the balanced water supply.

2. The method of claim 1 , wherein, when the absorption rate is greater than the release rate, the rate ratio is greater than one and the balance tank adjusts the first concentration such that the second concentration of the biocidal halogen species is lower than the first concentration of the biocidal halogen species.

3. The method of claim 1, wherein, when the absorption rate is less than the release rate, the rate ratio is less than one and the balance tank adjusts the first concentration such that the second concentration of the biocidal halogen species is greater than the first concentration of the biocidal halogen species.

4. The method of claim 1, wherein, when the absorption rate is equal to the release rate, the rate ratio is equal to one and the adjustment effect is that the second concentration of the biocidal halogen species is substantially the same as the first concentration of the biocidal halogen species.

5. The method of any preceding claim, wherein the first concentration of the biocidal halogen species has an associated tolerance level and the second concentration of the biocidal halogen species has an associated tolerance level, wherein the tolerance level represents a statistical deviation from a mean concentration value, wherein the second concentration of biocidal halogen species in the balanced water has a lower tolerance level than the first concentration of the biocidal halogen species in the disinfected water supply.

6. The method of any preceding claim, wherein the first polymeric medium and the second polymeric medium are selected to be substantially the same medium.

7. The method of any preceding claim, wherein the second concentration of the biocidal halogen species in the balanced water supply is between 0.3 ppm and 2 ppm.

8. The method of any preceding claim, wherein, the first polymeric medium includes a greater percentage by weight (wt%) of the biocidal halogen species than the percentage by weight (wt%) of the releasable biocidal halogen species in the second polymeric medium at an initial time to.

9. The method of claim 8, wherein the first polymeric medium comprises between 30 wt% and 40 wt% of the biocidal halogen species at the initial time to.

10. The method of claim 8 or 9, wherein the first concentration of the biocidal halogen species that is initially released into the first water supply at the initial time to is between 5 ppm and 15 ppm, preferably about 10 ppm.

11. The method of any of claims 8-10, wherein the first concentration of the biocidal halogen species in the disinfected water supply decreases with an increasing total volume of the first water supply that has passed through the disinfection unit at a time t > to.

12. The method of any of claims 8-11 , wherein the second polymeric medium comprises between 0 wt% and 20 wt% of the biocidal halogen species at the initial time to.

13. The method of any of claims 8-12, wherein the second polymeric medium initially releases a concentration of the biocidal halogen species between 0.1 ppm and 1 ppm at the initial time to.

14. The method of any of claims 8-13, wherein a percentage by weight (wt%) of the releasable biocidal halogen species in the second polymeric medium varies as the total volume of disinfected water that has come into contact with the second polymeric medium increases since the initial time to.

15. The method of any of claims 8-14, wherein the second polymeric medium initially reversibly binds with the biocidal halogen species to absorb a concentration of the biocidal halogen species between 1 ppm and 15 ppm at the initial time to.

16. The method of any preceding claim, wherein a percentage by weight (wt%) of the releasable biocidal halogen species in the second polymeric medium increases when the rate ratio is greater than 1 , decreases when the rate ratio is less than 1 , and stays the same when the rate ratio is equal to 1.

17. The method of any preceding claim, wherein the biocidal halogen species (e.g. chlorine, e.g. bromine) is covalently bound to the first polymeric medium.

18. The method of any preceding claim, wherein the biocidal halogen species (e.g. chlorine, e.g. bromine) is reversibly covalently bound to the second polymeric medium.

19. The method of any preceding claim, wherein the first and/or second polymeric medium including the biocidal halogen species is a polymeric medium comprising N- halamine polymer, e.g. N-halogenated poly(styrenehydantoin).

20. The method of claim 13 wherein the first and/or second polymeric medium including the releasable biocidal halogen species is N-halogenated poly(styrenehydantoin).

21. The method of any preceding claim, further comprising: means for monitoring a total volume of the first water supply that has passed through the disinfection unit since an initial time tO; and alert means for indicating when to replace or replenish one or more of the water disinfection cartridges based on the total volume.

22. The method of any preceding claim, further comprising: monitoring a total volume of the water supply that has passed through the balance tank since an initial time tO; and indicating when to replace or replenish the balance tank based on the total volume.

23. The method of any preceding claim, further comprising: a dilution inlet arranged to bring a second water supply to combine with the disinfected water supply downstream of the water disinfection cartridges to produce a combined water supply; wherein the balance tank inlet is arranged to bring the combined water supply to the balance tank.

24. The method of claim 23, wherein the system further comprises a controller configured to control a ratio in which the disinfected water supply and the second water supply are combined in order to achieve a desired third concentration of the biocidal halogen species in the combined water supply.

25. The method of claim 24, wherein the combined water supply has a third concentration of the biocidal halogen species of between 0.3 ppm and 2 ppm.

26. The method of claim 24 or 25, wherein the controller controls the ratio in which the disinfected water supply and the second water supply are combined in order to achieve a desired third concentration of the biocidal halogen species in the combined water supply by: monitoring a total volume of the first water supply that has passed through the water disinfection cartridges since an initial time tO; and setting the ratio in which the disinfected water supply and the second water supply are combined based on the total volume.

27. The method of any of claims 23-26, wherein the second water supply comprises a substantially zero concentration of the biocidal halogen species when the second water supply is combined with the disinfected water supply.

28. The method of any of claims 23-27, wherein the second water supply is arranged to pass through a number n (n>1) of dilution line disinfection cartridges, wherein each dilution line disinfection cartridge comprises a third polymeric medium including the releasable biocidal halogen species that is released into water coming into contact with the third polymeric medium, to produce a disinfected dilution water supply having a fourth concentration of the biocidal halogen species; wherein it is the disinfected dilution water supply that is combined with the disinfected water supply to produce the combined water supply, wherein the third concentration of the biocidal halogen species is less than the first concentration of biocidal halogen species in the disinfected water supply.

29. The method of any preceding claim, wherein a plurality (i.e. n>2) of the water disinfection cartridges are in a parallel arrangement and one or more controllable valves are arranged in the first water supply, each controllable valve arranged in series with an associated disinfection cartridge of the plurality of disinfection cartridges; and further comprising a controller configured to selectively operate the one or more controllable valves in response to the one or more flow parameters relating to the first water supply; wherein the selective operation of the one or more controllable valves includes opening or closing the controllable valves in response to the one or more flow parameters.

30. The method of claim 29, wherein the one or more parameters relating to the flow of water through the disinfection inlet comprise one or more of: actual flow rate, average flow rate, total volume of water.

31. The method of any preceding claim, wherein the biocidal halogen species comprises oxidative halogen, for example oxidative bromine.

32. A method of refurbishing the system of any of claims 1-31, the method comprising: monitoring the total volume to have passed through the disinfection unit since an initial time tO; comparing the total volume to an expected disinfection cartridge lifetime; and replacing or recharging the first polymeric medium at the end of a disinfection cartridge lifetime.

33. The method of claim 32, wherein the expected disinfection cartridge lifetime is associated with the percentage by weight (wt%) of the biocidal halogen species in the first polymeric medium falling below about 20 wt%.

34. The method of claim 32 or 33, wherein the expected disinfection cartridge lifetime is associated with the first concentration of the biocidal halogen species in the disinfected water supply falling below about 0.5 ppm or 0.3 ppm.

35. A method of refurbishing the system of any of claims 1-31, the method comprising: monitoring the total volume of the water supply to have passed through the balance tank since an initial time tO; comparing the total volume to an expected balance tank lifetime; and replacing or recharging the second polymeric medium at the end of a balance tank lifetime.

36. The method of claim 35, wherein the expected balance tank lifetime is associated with the percentage by weight (wt%) of the biocidal halogen species in the second polymeric medium falling below about 10 wt%.

37. The method of claim 35 or 36, wherein the expected balance tank lifetime is associated with the second concentration of the biocidal halogen species in the balanced water supply falling below about 0.5 ppm or 0.3 ppm.

38. A method according to any of claims 32-34, used in combination with the method of any of claims 35-37.

39. A system for disinfecting water for animal consumption, the system comprising: a disinfection inlet arranged to bring a first water supply to a disinfection unit; the disinfection unit comprising a number n (n>1) of water disinfection cartridges, wherein each water disinfection cartridge comprises a first polymeric medium including a releasable biocidal halogen species that is released into the first water supply coming into contact with the first polymeric medium to provide a disinfected water supply, wherein the disinfected water supply has a first concentration of the biocidal halogen species; a balance tank inlet arranged to bring the disinfected water supply to a balance tank; the balance tank comprising a second polymeric medium including: the releasable biocidal halogen species, arranged to be available to be released at a release rate into the disinfected water supply coming into contact with the second polymeric medium; and vacant binding sites, arranged to reversibly bind at an absorption rate with the biocidal halogen species in the disinfected water supply coming into contact with the second polymeric medium; wherein a ratio of the absorption rate to the release rate defines a rate ratio of the second polymeric medium; and wherein the rate ratio of the second polymeric medium determines an adjustment effect that the balance tank has on the first concentration of biocidal halogen species in the disinfected water supply to achieve a second concentration of the biocidal halogen species in a balanced water supply output from the balance tank.

40. The system of claim 39, wherein, when the absorption rate is greater than the release rate, the rate ratio is greater than one and the balance tank is configured to adjust the first concentration such that the second concentration of the biocidal halogen species is lower than the first concentration of the biocidal halogen species.

41. The system of claim 39, wherein, when the absorption rate is less than the release rate, the rate ratio is less than one and the balance tank is configured to adjust the first concentration such that the second concentration of the biocidal halogen species is greater than the first concentration of the biocidal halogen species.

42. The system of claim 39, wherein, when the absorption rate is equal to the release rate, the rate ratio is equal to one and the balance tank is configured to provide an adjustment effect such that the second concentration of the biocidal halogen species is substantially the same as the first concentration of the biocidal halogen species.

43. The system of any of claims 39-42, wherein the first concentration of the biocidal halogen species has an associated tolerance level and the second concentration of the biocidal halogen species has an associated tolerance level, wherein the tolerance level represents a statistical deviation from a mean concentration value, wherein the second concentration of biocidal halogen species in the balanced water has a lower tolerance level than the first concentration of the biocidal halogen species in the disinfected water supply.

44. The system of any of claims 39-43, wherein the first polymeric medium including the biocidal halogen species is a polymeric medium comprising N-halamine polymer, e.g. N- halogenated poly(styrenehydantoin) and/or the second polymeric medium including the biocidal halogen species is a polymeric medium comprising N-halamine polymer, e.g. N- halogenated poly(styrenehydantoin).

45. The system of any of claims 39-44, wherein the first polymeric medium and the second polymeric medium are selected to be substantially the same medium.

46. The system of any of claims 39-45, wherein the second concentration of the biocidal halogen species in the balanced water supply is between 0.3 ppm and 2.0 ppm.

47. The system of any of claims 39-46, wherein, the first polymeric medium includes a greater percentage by weight (wt%) of the biocidal halogen species than the percentage by weight (wt%) of the releasable biocidal halogen species in the second polymeric medium at an initial time to.

48. The system of claim 47, wherein the first polymeric medium comprises between 30 wt% and 40 wt% of the biocidal halogen species at the initial time to.

49. The system of claim 46 or 47, wherein the first concentration of the biocidal halogen species that is initially released into the first water supply at the initial time to is between 5 ppm and 15 ppm, preferably about 10 ppm.

50. The system of any of claims 47-49, wherein the first concentration of the biocidal halogen species in the disinfected water supply decreases with an increasing total volume of the first water supply that has passed through the disinfection unit at a time t > to.

51. The system of any of claims 47-50, wherein the second polymeric medium comprises between 0 wt% and 20 wt% of the biocidal halogen species at the initial time to.

52. The system of any of claims 47-51 , wherein the second polymeric medium initially releases a concentration of the biocidal halogen species between 0.1 ppm and 1 ppm at the initial time to.

53. The system of any of claims 47-52, wherein a percentage by weight (wt%) of the releasable biocidal halogen species in the second polymeric medium varies as the total volume of disinfected water that has come into contact with the second polymeric medium increases since the initial time to.

54. The system of any of claims 47-53, wherein the second polymeric medium initially reversibly binds with the biocidal halogen species to absorb a concentration of the biocidal halogen species between 1 ppm and 15 ppm at the initial time to.

55. The system of any of claims 39-54, wherein a percentage by weight (wt%) of the releasable biocidal halogen species in the second polymeric medium increases when the rate ratio is greater than 1 , decreases when the rate ratio is less than 1 , and stays the same when the rate ratio is equal to 1.

56. The system of any of claims 39-55, further comprising: means for monitoring a total volume of the first water supply that has passed through the disinfection unit since an initial time tO; and alert means for indicating when to replace or replenish one or more of the water disinfection cartridges based on the total volume.

57. The system of any of claims 39-56, further comprising: means for monitoring a total volume of the water supply that has passed through the balance tank since an initial time tO; and alert means for indicating when to replace or replenish the balance tank based on the total volume.

58. The system of any of claims 39-57, further comprising: a dilution inlet arranged to bring a second water supply to combine with the disinfected water supply downstream of the water disinfection cartridges to produce a combined water supply; wherein the balance tank inlet is arranged to bring the combined water supply to the balance tank.

59. The system of claim 58, wherein the system further comprises a controller configured to control a ratio in which the disinfected water supply and the second water supply are combined in order to achieve a desired third concentration of the biocidal halogen species in the combined water supply.

60. The system of claim 59, wherein the combined water supply has a third concentration of the biocidal halogen species of between 0.3 ppm and 2.0 ppm.

61. The system of claim 59 or 60, wherein the controller controls the ratio in which the disinfected water supply and the second water supply are combined in order to achieve a desired third concentration of the biocidal halogen species in the combined water supply by: monitoring a total volume of the first water supply that has passed through the water disinfection cartridges since an initial time tO; and setting the ratio in which the disinfected water supply and the second water supply are combined based on the total volume.

62. The system of any of claims 58-61 , wherein the second water supply comprises a substantially zero concentration of the biocidal halogen species when the second water supply is combined with the disinfected water supply.

63. The system of any of claims 58-561 , wherein the second water supply is arranged to pass through a number n (n>1) of dilution line disinfection cartridges, wherein each dilution line disinfection cartridge comprises a third polymeric medium including the releasable biocidal halogen species that is released into water coming into contact with the third polymeric medium, to produce a disinfected dilution water supply having a fourth concentration of the biocidal halogen species; wherein it is the disinfected dilution water supply that is combined with the disinfected water supply to produce the combined water supply, wherein the third concentration of the biocidal halogen species is less than the first concentration of biocidal halogen species in the disinfected water supply.

64. The system of any of claims 39-63, wherein a plurality (i.e. n>2) of the water disinfection cartridges are in a parallel arrangement and one or more controllable valves are arranged in the first water supply, each controllable valve arranged in series with an associated disinfection cartridge of the plurality of disinfection cartridges; and further comprising a controller configured to selectively operate the one or more controllable valves in response to the one or more flow parameters relating to the first water supply; wherein the selective operation of the one or more controllable valves includes opening or closing the controllable valves in response to the one or more flow parameters. - 91 -

65. The system of claim 64, wherein the one or more parameters relating to the flow of water through the disinfection inlet comprise one or more of: actual flow rate, average flow rate, total volume of water.

66. The system of any of claims 39-65, wherein the biocidal halogen species comprises oxidative halogen, for example oxidative bromine or chlorine, wherein the oxidative halogen is covalently bound to the first polymeric medium, and wherein the second polymeric medium includes vacant binding sites arranged to reversibly covalently bind with the oxidative halogen.

67. The system of any of claims 39-66, wherein the system is an animal drinking water treatment and distribution system, the system further comprising: the balanced water supply being arranged to pass from the balance tank to a drinking water distribution system for animal consumption.

68. Use of the system of any of claims 39-67 to treat water for animal consumption.

69. A method of refurbishing the system of any of claims 39-67, the method comprising: monitoring the total volume to have passed through the disinfection unit since an initial time tO; comparing the total volume to an expected disinfection cartridge lifetime; and replacing or recharging the first polymeric medium at the end of a disinfection cartridge lifetime.

70. The method of claim 69, wherein the expected disinfection cartridge lifetime is associated with the percentage by weight (wt%) of the biocidal halogen species in the first polymeric medium falling below about 20 wt%.

71. The method of claim 69 or 70, wherein the expected disinfection cartridge lifetime is associated with the first concentration of the biocidal halogen species in the disinfected water supply falling below about 0.3 ppm.

72. A method of refurbishing the system of any of claims 39-67, the method comprising: monitoring the total volume of the water supply to have passed through the balance tank since an initial time tO; comparing the total volume to an expected balance tank lifetime; and - 92 - replacing or recharging the second polymeric medium at the end of a balance tank lifetime.

73. The method of claim 72, wherein the expected balance tank lifetime is associated with the percentage by weight (wt%) of the biocidal halogen species in the second polymeric medium falling below about 10 wt%.

74. The method of claim 72 or 73, wherein the expected balance tank lifetime is associated with the second concentration of the biocidal halogen species in the balanced water supply falling below about 0.3 ppm.

75. A method according to any of claims 69-71, used in combination with the method of any of claims 72-74.