Medical water preparation

Abstract

The apparatus is operable to prepare water for use in medical procedures based on a water supply (W1), e.g., tap water. The apparatus includes a filtration device (21) and an irradiation device (22) connected in series to sequentially process the water supply (W1) into dechlorinated water (W1'). The filtration device (21) and the irradiation device (22) are redundant to each other, both configured to effectively remove chlorine from the water supply, the filtration device (21) using one or more activated carbon filters, and the filtration device (21) using ultraviolet (UV) irradiation. Combining different removal technologies in a redundant manner reduces the need for intermittent sampling and analysis of water downstream of the filtration device (21). Furthermore, the operation of the filtration device (21) and / or the irradiation device (22) can be monitored via the irradiation device (22) to detect faults.

Description

[Technical Field]

[0001] The present disclosure relates generally to the field of medical procedures, and more particularly to techniques for removing chlorine from water supplies to produce water for use in medical procedures. [Background technology]

[0002] Water can be used to produce medical fluids for use in medical procedures. Medical fluid production can be performed centrally or at the bedside. Water must meet strict requirements set by standards or guidelines regarding both sterility and the content of potentially harmful substances. Water can be produced from tap water by dedicated water preparation equipment equipped with water purification systems operating by reverse osmosis and / or ion exchange. These water purification systems are highly sensitive to the chlorine typically present in tap water. Therefore, water preparation equipment can include a pretreatment stage to remove chlorine from the influent water by filtration through activated carbon. To mitigate the risk of channeling, where the influent water passes through the activated carbon without being fully dechlorinated, the water preparation equipment can include two carbon beds, each redundant to the other and connected in series to receive the influent water. By being redundant, each carbon bed is separately configured to achieve sufficient dechlorination of the influent water. The use of dual carbon beds requires frequent manual inspection of the filtered water between the carbon beds to ensure redundancy is maintained, protecting the health of both the patient and downstream equipment. Testing is costly, time consuming, and involves manual handling of water samples. Currently, no equipment exists that allows for automated, cost-effective measurement of chlorine in water. Summary of the Invention

[0003] U.S. Patent Application Publication No. 2013 / 0126430 discloses a water purification system in which raw water passes through one or more carbon block filters to remove chlorine and chloramine compounds. A UV device is disposed downstream of the carbon block filters to irradiate the water with UV radiation to ensure the sterility of the water. As can be understood, U.S. Patent Application Publication No. 2013 / 0126430 also proposes replacing the carbon block filter(s) for a UV device configured to achieve both dechlorination and sterilization of the raw water.

[0004] SUMMARY OF THE INVENTION It is an object of the present invention to at least partially overcome one or more limitations of the prior art.

[0005] One objective is to alleviate the need to manually measure the chlorine content of water during operation of a device for preparing water for medical use.

[0006] One or more of these objects, as well as further objects that may become apparent from the following description, are at least partly achieved by an apparatus, a system and a method for preparing water according to the independent claims, embodiments of which are defined by the dependent claims.

[0007] A first aspect is an apparatus for preparing water for use in medical treatment of the human or animal body. The apparatus is configured to receive a supply of water from a water source. The apparatus includes a filtration device configured to effectively remove chlorine from the supply of water through the use of one or more activated carbon filters, and an irradiation device configured to effectively remove chlorine from the supply of water through ultraviolet (UV) irradiation. The filtration device and the irradiation device are connected in series to sequentially process the supply of water into dechlorinated water. The apparatus is configured to provide conditioned water for use in the medical treatment based on the dechlorinated water.

[0008] In some embodiments, the illumination device comprises a casing defining a treatment chamber, an inlet to the treatment chamber for influent water, and an outlet from the treatment chamber for effluent water, the illumination device further comprising at least one source of UV radiation arranged to illuminate at least a portion of the treatment chamber.

[0009] In some embodiments, the irradiation devices further comprise at least one sensor configured to generate a measurement signal indicative of UV radiation intensity within the processing chamber, and the apparatus further comprises a control device configured to receive the measurement signal and monitor operation of at least one of the irradiation devices of the filtering device based on the measurement signal.

[0010] In some embodiments, the control device is configured to evaluate the UV radiation intensity in the processing chamber relative to an intensity limit based on the measurement signal, and generate a warning indicating a failure of the irradiation device if the UV radiation intensity falls below the intensity limit.

[0011] In some embodiments, the failure comprises at least one of a reduction in radiant power of at least one source of UV radiation or contamination within the processing chamber.

[0012] In some embodiments, the intensity limit corresponds to the illumination device being operable to effectively remove the chlorine in the supply water.

[0013] In some embodiments, the at least one source of UV radiation comprises a light emitting diode or a laser diode.

[0014] In some embodiments, the at least one source of UV radiation comprises a first radiation-emitting element and a second radiation-emitting element, the first and second radiation-emitting elements configured to emit UV radiation in different wavelength ranges.

[0015] In some embodiments, the control device is configured to activate the first radiation-emitting element, the second radiation-emitting element, or both the first and second radiation-emitting elements for the removal of the chlorine in the supply water.

[0016] In some embodiments, the control device is configured to selectively activate at least one of the first or second radiation-emitting elements based on input data representing the composition of the chlorine in the feedwater.

[0017] In some embodiments, the first radiation-emitting element is configured to preferentially remove monochloramine over free chlorine and dichloramine, and the second radiation-emitting element is configured to preferentially remove free chlorine and dichloramine over monochloramine.

[0018] In some embodiments, the first radiation-emitting element is configured to generate UV radiation having a peak in a first wavelength range of 240 to 265 nm, and the second radiation-emitting element is configured to generate UV radiation having a peak in a second wavelength range of 265 to 290 nm.

[0019] In some embodiments, the at least one source of UV radiation is configured to generate UV radiation within a wavelength range of 100 to 400 nm, preferably within a wavelength range of 200 to 325 nm.

[0020] In some embodiments, the irradiation device is configured to operate with a continuous flow of water through the treatment chamber from the inlet to the outlet.

[0021] In some embodiments, the control device is configured to detect channel formation in the one or more activated carbon filters of the filtering device based on the measurement signals, and to generate an alert signal in response to detecting the channel formation.

[0022] In some embodiments, the control device is configured to evaluate the measurement signal for detection of a decrease in a step change in the measurement signal relative to the detection of the channel formation.

[0023] In some embodiments, the control device is configured to detect the decrease in the step change by comparing a signal level in the measurement signal to a threshold value.

[0024] In some embodiments, the control device is configured to determine a reference level as a function of a previous signal value in the measurement signal at a current time point, set the threshold value with respect to the reference level, and compare the signal level in the measurement signal at the current time point with the threshold value.

[0025] In some embodiments, the illumination device comprises a further source of UV radiation and a further sensor arranged downstream of the at least one source and the sensor, the further sensor arranged to generate a further measurement signal indicative of the UV radiation intensity received from the further source, and the control device configured to detect the channel formation based on the measurement signal and the further measurement signal.

[0026] In some embodiments, the control device is configured to evaluate the further measurement signal for detection of a decrease in the further step change of the further measurement signal relative to the detection of the channel formation.

[0027] In some embodiments, the control device is configured to generate the warning signal when a decrease in the further step change of the further measurement signal is detected in time synchronization with a corresponding decrease in the step change of the measurement signal.

[0028] In some embodiments, the filtering device is located upstream of the illumination device.

[0029] In some embodiments, the filtration device and the irradiation device are included in a pre-treatment subsystem, and the apparatus further comprises a main subsystem configured to receive the dechlorinated water from the pre-treatment subsystem and configured to process the dechlorinated water to produce the conditioned water.

[0030] In some embodiments, the main subsystem comprises at least one of a reverse osmosis device or an ion exchange device.

[0031] In some embodiments, the filtration device and the irradiation device are connected in series without intervening treatment equipment for removing chlorine.

[0032] In some embodiments, the device is configured to supply the conditioned water to a dialysis machine.

[0033] In some embodiments, the filtration device includes a single activated carbon filter configured to effectively remove the chlorine in the supply water.

[0034] In some embodiments, the irradiation device is configured to remove a first target amount of the chlorine from the supply water, and the filtration device is configured to remove a second target amount of the chlorine from the supply water, the second target amount being at least equal to the first target amount and less than twice the first target amount.

[0035] A second aspect is a system comprising the apparatus for preparing water according to the first aspect or any of its embodiments, and a dialysis machine fluidly connected to receive conditioned water from the apparatus for preparing water.

[0036] A third aspect is a method for preparing water for use in a medical treatment of a human or animal body. The method includes receiving a supply of water from a water source and operating a filtration device and an irradiation device connected in series to sequentially process the supply of water into dechlorinated water, the filtration device configured to effectively remove chlorine in the supply of water by filtration through activated carbon and the irradiation device configured to effectively remove chlorine in the supply of water by ultraviolet (UV) irradiation. The method further includes providing conditioned water for use in the medical treatment based on the dechlorinated water.

[0037] An embodiment of the first aspect may be adapted as an embodiment of the third aspect.

[0038] Further objects, aspects, embodiments, and technical effects, as well as features and advantages, may become apparent from the following detailed description, the appended claims, and the drawings. [Brief explanation of the drawings]

[0039] [Figure 1A] , [Figure 1B] , [Figure 1C] 1A-1B are schematic diagrams of an exemplary system for dialysis treatment, and FIG. 1C is a block diagram of an exemplary water preparation device for use in the system of FIGS. 1A-1B. [Figure 2] Figure 2 is an example of a reference subsystem for removing chlorine from water by activated carbon filtration. [Figure 3] FIG. 3 is a block diagram of an exemplary dechlorination subsystem in a water preparation apparatus, according to one embodiment. [Figure 4A] , [Figure 4B] 4A-4B are cross-sectional views of the illumination device and the filtering device in the dechlorination subsystem of FIG. 3, according to an embodiment. [Figure 5]FIG. 5 is a graph of the absorption spectra of two chloramines overlaid with the emission spectra of three exemplary UV-LEDs. [Figure 6A] , [Figure 6B] , [Figure 6C] , [Figure 6D] FIG. 6A is a flowchart of an exemplary configuration process for the dechlorination subsystem of FIG. 3, and FIGS. 6B-6D are flowcharts of an exemplary process for operating a water preparation apparatus, according to an embodiment. [Figure 7] FIG. 7 is a schematic diagram of an exemplary main subsystem of a water preparation machine. [Figure 8A] , [Figure 8B] 8A-8B are graphs of experimental results for dechlorination by UV radiation. [Figure 9A] , [Figure 9B] FIG. 9A shows a first illumination device, and FIG. 9B is a graph of an exemplary signal from the first illumination device during channeling in an upstream filtering device. [Figure 10A] , [Figure 10B] FIG. 10A shows a second illumination device, and FIG. 10B is a graph of an exemplary signal from the second illumination device during channeling in an upstream filtering device. DETAILED DESCRIPTION OF THE INVENTION

[0040] Embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all, embodiments are shown. Indeed, the subject matter of this disclosure may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein, but rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements.

[0041] It will also be understood that, where possible, any of the advantages, features, functions, devices, and / or operational aspects of any of the embodiments described and / or contemplated herein can be included in any of the other embodiments described and / or contemplated herein, and / or vice versa. Furthermore, where possible, any term expressed in the singular herein is intended to include the plural and / or vice versa, unless expressly stated otherwise. As used herein, "at least one" means "one or more," and these phrases are intended to be interchangeable. Thus, the terms "a" and / or "an" shall mean "at least one" or "one or more," although the expressions "one or more" or "at least one" are also used herein. As used herein, unless the context requires otherwise to express the words or necessary connotation, the words "comprise," or variations such as "comprises," or "comprising," are used in an inclusive sense, i.e., to specify the presence of stated features but not to preclude the presence or addition of additional features in various embodiments.

[0042] As used herein, the terms "multiple," "plural," and "plurality" are intended to connote the presence of more than one element. The term "and / or" includes any and all combinations of one or more of the associated listed elements.

[0043] Furthermore, while terms such as "first," "second," and the like may be used herein to describe various elements, it should be understood that these elements should not be limited by these terms. These terms are used only to distinguish one element from another. For example, a first element can be referred to as a second element, and similarly, a second element can be referred to as a first element, without departing from the scope of the present disclosure.

[0044] Known functions or configurations may not be described in detail for the sake of brevity and / or clarity. Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs.

[0045] Like numbers refer to like elements throughout.

[0046] The present disclosure relates to techniques for preparing water for use in medical treatment of the human or animal body. As used herein, medical treatment is an attempt to ameliorate a health problem and includes any treatment in which water comes into contact with the body. This disclosure may particularly relate to current or future treatments in which water is mixed with one or more concentrates, either centrally in a clinic or by a bedside machine, to form a medical fluid capable of interacting with the patient's blood. Such treatments include dialysis treatment, plasma exchange, apheresis (apheresis), extracorporeal membrane oxygenation, assisted blood circulation, extracorporeal liver support / dialysis, and the like. This "on-demand generation" of medical fluids is expected to become increasingly common in the future. On-demand generation allows medical fluids to be produced in the quantities needed and also allows the composition of the medical fluid to be adjusted. Traditionally, pre-made medical fluids are transported to clinics in containers or bags. On-demand generation reduces the need to store and handle pre-made medical fluids at clinics.

[0047] As mentioned above, the water preparation technology is applicable to dialysis treatments.

[0048] As used herein, "dialysis therapy" refers to any therapy that replaces or supplements a patient's kidney function through the use of dialysis fluid. Dialysis therapy includes, but is not limited to, extracorporeal (EC) blood therapy and peritoneal dialysis (PD) therapy. Examples of EC blood therapy include hemodialysis (HD), hemofiltration (HF), and hemodiafiltration (HDF). For context only, fluid generation for EC blood therapy and PD therapy will be briefly described with reference to Figures 1A-1B.

[0049] FIG. 1A is a general schematic of a system for EC blood therapy. The system includes a water preparation apparatus (WPA) 20 and a dialysis machine 30. The WPA 20 is connected by a first fluid line 41 and receives incoming feedwater W1 from a water source 10. The feedwater W1 may be tap water (potable water) or some form of pretreated tap water. The WPA 20 is configured to process W1 into conditioned water W2, which is of sufficient quality for use in EC blood therapy, commonly known as "water for dialysis" (for use in preparing dialysis fluids, ultrapure dialysis fluids, and online-prepared substitution fluids). The quality of W2 is provided by standards or guidelines, such as ANSI / AAMI / ISO 23500-3:2019. The dialysis machine 30 is connected by a second fluid line 42 and receives W2 from the WPA 20. The dialysis machine 30 is configured to mix W2 with one or more concentrates to produce treatment fluids, such as dialysis fluid and / or substitution fluids, for use in EC blood therapy. The dialysis machine 30 is fluidly connected to the vascular system of the patient P via a fluid pathway. In the illustrated example, the fluid pathway is defined by tubing 43 for blood withdrawal (collection) and tubing 44 for blood return. As indicated by the arrows, the dialysis machine 30 is operable to withdraw blood from the patient P through tubing 43, process the blood, and return the processed blood to the patient through tubing 44. Tubes 43, 44 are connected to an access device (e.g., a catheter, graft, or fistula, not shown) that is in fluid communication with the patient P's vascular system. The dialysis machine 30 may be configured to treat the blood through the use of a treatment fluid. For example, a dialysis fluid may be connected to the blood within the dialyzer, and / or a substitution fluid may be added to the blood, as is known in the art.

[0050] FIG. 1B is a general schematic of a system for PD treatment. Similar to FIG. 1A, the system includes a water processor (WPA) 20 configured to generate conditioned water W2 ("water for dialysis" or "water for infusion") from a supply water W1 received from a water source 10. The quality of W2 may be provided by standards or guidelines for PD treatment. A dialysis machine 30 is fluidly connected to a peritoneal cavity PC of a patient P. The dialysis machine 30 is configured to mix W2 with one or more concentrates to generate a treatment fluid for use in PD treatment. As indicated by the double-headed arrow, the dialysis machine 30 is operable to deliver fresh treatment fluid to the peritoneal cavity PC and to receive spent treatment fluid from the PC over a fluid path 43. The fluid path 43 may be defined by tubing connecting to an implanted catheter (not shown) in fluid communication with the PC. The dialysis machine 30 may be configured for any type of PD treatment and may include a dialysis machine ("cycler") that performs the dialysis treatment, as is known in the art.

[0051] FIG. 1C is a general schematic of a water preparation apparatus (WPA) 20 that may be used in the systems of FIGS. 1A-1B as well as other systems for medical procedures. WPA 20 includes a pretreatment subsystem 20′ connected to receive feedwater W1 on fluid line 41. Subsystem 20′ is configured to process W1 to produce dechlorinated water W1′. Subsystem 20′ is hereinafter referred to as the “dechlorination subsystem.” Main subsystem 20″ is connected to receive dechlorinated water W1′ from dechlorination subsystem 20′ on connecting fluid line 20A, and main subsystem 20″ is configured to perform final treatment of dechlorinated water W1′ to produce conditioned water W2, which is output on fluid line 42. As will be appreciated from the above, W2 is produced of a quality acceptable for use in the intended medical procedure. In a non-limiting example applicable to "water for dialysis," W2 meets the maximum allowable levels of toxic chemicals: aluminum 0.01 ppm, copper 0.1 ppm, fluoride 0.2 ppm, lead 0.005 ppm, nitrates 2 ppm, sulfites 100 ppm, zinc 0.1 ppm, and total chlorine 0.1 ppm.

[0052] The WPA 20 is configured to purify W1. Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The primary removal of impurities in W1 is performed by the main subsystem 20''. Such impurities include ionic and organic contaminants. The main subsystem 20'' typically includes one or more advanced purification devices, for example, using membrane filtration or ion exchange, or a combination thereof. One membrane filtration technology commonly used for water purification is reverse osmosis (RO), in which RO membranes are used to separate ions, molecules, and larger particles from water. Ion exchangers (IEX) are also commonly used for water purification. Simply put, ion exchangers operate to remove ionic impurities from water by replacing each ionic impurity with another ionic material. Typical ion exchangers are ion exchange resins (functionalized porous or gel polymers), zeolites, montmorillonite, clay, or soil humus. Electrodeionization (EDI) is also used for water purification. In principle, any conventional or future water purification technology can be implemented in the main subsystem 20'', depending on the required quality of W2.

[0053] The dechlorination subsystem 20' is configured to effectively remove chlorine from the feedwater W1. As used herein, "effectively remove" means that the total amount of chlorine in the dechlorinated water W1' is about 0.1 mg / L (0.1 ppm) or less.

[0054] Tap water may contain chlorine, often referred to as residual chlorine, as a result of water chlorination, which occurs at the water treatment plant where the water is produced. Water chlorination is the process of adding chlorine or chlorine compounds, such as hypochlorous acid, to water to kill bacteria, viruses, and other microorganisms in the water. Chlorination, in particular, is used to prevent the spread of waterborne diseases such as cholera, dysentery, and typhoid fever. Residual chlorine is the amount of chlorine remaining in water after a certain period or contact time, such as 30 minutes. In the United States, total chlorine concentrations up to 4 mg / L (4 ppm) are considered safe for drinking water. Residual chlorine can exist in chlorinated tap water in both free and bound forms. Free forms can include dissolved hypochlorite ions, hypochlorous acid, and chlorine gas. Bound forms can include chloramines, which kill bacteria and oxidize organic matter. Examples of such chloramines include monochloramine, dichloramine, and trichloramine. The total amount of chlorine is given by the sum of free and bound chlorine.

[0055] One reason for installing the dechlorination subsystem 20′ upstream of the main subsystem 20″ is to protect the main subsystem 20″ and, ultimately, the patient. Many advanced purification devices are sensitive to the strong oxidizing properties of chlorine. For example, the RO membrane in an RO device is easily and irreversibly damaged by chlorine. Similarly, the ion exchangers in an ion exchange device can be irreversibly damaged by chlorine. Even if the main subsystem 20″ is resistant to chlorine, the dechlorination subsystem 20″ can be installed to reduce the operating requirements of the main subsystem 20″. The dechlorination subsystem 20′ not only removes residual chlorine but also reduces the amount of particles, total dissolved solids (TDS), volatile organic compounds (VOCs), trihalomethanes (THMs), heavy metals, and the like in the feedwater W1.

[0056] FIG. 2 shows an example of a dechlorination subsystem 20′ that operates by passing feedwater through a series of activated carbon (AC) filters 100. This example is provided to motivate the techniques described below with reference to FIGS. 3-6. In FIG. 2, an inlet line 101 is fluidly connected to the inlet of a first AC filter 100, a connecting line 102 is fluidly connected to the outlet of the first AC filter 100 and the inlet of a second AC filter 100, and an outlet line 103 is fluidly connected to the outlet of the second AC filter 100. Each AC filter 100 is formed by a container that holds activated carbon 100A, also known as active carbon or activated charcoal. The activated carbon 100A is treated (activated) to have small, low-volume pores that increase the surface area available for adsorption or chemical reaction. The activated carbon 100A forms a bed (layer) within the container. The activated carbon bed (layer) is arranged to remove chlorine from the incoming water and absorb toxic substances and pesticides. In an exemplary embodiment, the activated carbon bed is arranged to remove free and bound chlorine. In a further exemplary embodiment, the activated carbon bed is also arranged to reduce organic compounds (TOC, total organic carbon), including pesticides, in the influent water.

[0057] In the illustrated example, each AC filter 100 is independently configured to effectively remove chlorine from the supply water. The use of two AC filters 100 introduces redundancy in filtering capacity to prevent irreparable damage to downstream equipment if one of the AC filters 100 fails. For example, a known problem with AC filters 100 is channeling. When water enters the AC filter 100, it automatically flows through the filter 100 by the path of least resistance, creating one or more channels through the activated carbon 100A. Channeling likely results in inadequate removal of chlorine by the AC filter 100. AC filters 100 also degrade with use, resulting in reduced performance over time. In this reference example, early detection of failures is essential. Therefore, water passing through the connecting line 102 is regularly inspected for elevated chlorine concentrations. In the illustrated example, a diversion line 104, including an on-off valve 105, extends from the connecting line 102 to a sampling port 106. A water sample is taken at the sampling port 106 by opening the on-off valve 105, and the chlorine content in the sample is measured using a dedicated measuring device, such as a spectrometer, spectrophotometer, or color comparator. If a high level of chlorine is detected in the sample, the first AC filter 100 is discarded and replaced with a new one. Typically, a sample is taken and analyzed at the beginning of each day before a patient is first connected for treatment. Sampling and analysis may be repeated before a new patient is connected or every four hours while the WPA20 is in operation. This procedure is time-consuming and costly. Analysis requires specialized and expensive equipment. Sample collection is labor-intensive. Samples may need to be transported to the clinic's central laboratory for analysis. Handling test data from multiple WPA20s requires a management routine to minimize errors.

[0058] Applicant has discovered that this burdensome testing can be avoided, or at least reduced in scope, by using a novel concept involving combining AC filtration with irradiation with ultraviolet (UV) radiation. Specifically, AC filtration and UV irradiation are performed sequentially, with each being sufficient to effectively remove chlorine from the supply water W1. This makes UV irradiation redundant with respect to AC filtration. Thus, UV irradiation is redundant, similar to the second (downstream) AC filter 100 in subsystem 20′ of FIG. 2, with the important difference that UV irradiation can be monitored. AC filtration is a passive, purely mechanical process whose performance can only be evaluated by water testing. UV irradiation, on the other hand, is an active process that involves the generation of UV radiation. The performance of UV irradiation can be monitored via the generated UV radiation.

[0059] FIG. 3 illustrates an example of a dechlorination subsystem 20′ for use in a WPA 20 according to an embodiment of the aforementioned concepts. The subsystem 20′ receives feedwater W1 on input line 41 and outputs dechlorinated water W1′ on connecting fluid line 20A, which is received by the main subsystem 20 (FIG. 1C). The subsystem 20′ includes a filtration device 21 and an irradiation device 22 connected in series for sequentially processing the feedwater W1 into dechlorinated water W1′. In the illustrated example, the filtration device 21 is positioned upstream of the irradiation device 22 to receive and process the feedwater W1. The filtration device 21 includes a filter module 21A configured to effectively remove chlorine in W1 by filtration with activated carbon. Thus, treatment by the filtration device 21 results in dechlorinated water, referred to as “intermediate water,” designated W1″. A connecting fluid line 20B extends between the filtration device 21 and the irradiation device 22 for transporting W1″ to the irradiation device 22. The irradiation device 22 includes an irradiation module 22A configured to effectively remove chlorine in W1 by UV irradiation. The irradiation device 21 operates on W1'' and outputs dechlorinated water W1'.

[0060] Because the filtration device 21 and the irradiation device 22 in the subsystem 20′ are mutually redundant with respect to dechlorination, the intermediate water W1″ is sufficiently dechlorinated as long as the filtration device 21 functions properly. Therefore, the dechlorinated water W1′ produced by the irradiation device 22 may be identical to the intermediate water W1″ during proper operation of the filtration device 21. However, the irradiation device 22 may provide further dechlorination of the intermediate water W1, resulting in the subsystem 20′ reducing the total amount of chlorine to a greater extent than the level required by the main subsystem 21′.

[0061] It is understood that the filtering device 21 and / or the illumination device 22 may include additional components such as pumps, valves, sensors, tanks, etc. In the illustrated example, it is assumed that the filtering device 21 is operable to generate one or more measurement signals S1 and receive one or more control signals C1 for controlling its operation. In some implementations, S1 and / or C1 may be omitted. The illumination device 22 is operable to generate at least one measurement signal S2 and receive one or more control signals C2 for controlling its operation.

[0062] Because the filtration device 21 and the irradiation device 22 are separately configured to effectively remove chlorine from the incoming water, no additional equipment for chlorine removal is required in the dechlorination subsystem 20'. For example, there is typically no intervening equipment for chlorine removal along the water flow path between the filtration device 21 and the irradiation device 22.

[0063] In another embodiment (not shown), the irradiation device 22 is installed upstream of the filtration device 21. Thus, intermediate water W1″ is instead produced from the feed water W1 by the irradiation device 22 and conveyed via the connecting liquid line 20B to the filtration device 21, where dechlorinated water W1″ is produced from the intermediate water W1″.

[0064] It is currently believed to be beneficial to place the filtration device 21 upstream of the illumination device 22, as shown in Figure 3. The activated carbon bed is known to act as a nutrient-rich environment for microorganisms and can be considered a key point for microbial penetration into the rest of the fluid circuit. UV irradiation is known to reduce microbial activity. Therefore, placing the illumination device 22 downstream of the filtration device 21 can reduce the microbial load entering the main subsystem 20 (Figure 1C). This can protect patient health and also extend the life of downstream components within the WPA 20. The filtration device 21 can also reduce the amount of suspended solids in the water flowing into the illumination device 22. Suspended solids can impair the performance of the illumination device 22, for example, by absorbing or deflecting UV radiation or by fouling the illumination device 22.

[0065] The presence of suspended solids may alternatively or additionally be mitigated by including a particle filter upstream of the irradiation device 22 to remove particles such as clay, silt, and silicon. The particle filter may be a sediment filter and may be configured to filter out micrometer-sized particles, and optionally large endotoxin molecules, from the water passing therethrough.

[0066] Providing a dedicated particle filter may be particularly relevant if the illumination device 22 is arranged upstream of the filtering device 21 .

[0067] In some embodiments, the particle filter is incorporated into the filtering device 21.

[0068] The control device 50 is configured to implement logic for controlling the dechlorination system 20′ and, optionally, the main subsystem 20 (FIG. 1C). In the illustrated example, the control device 50 is configured to generate control signals C1, C2 based at least in part on the sensor signals S1, S2. The control device 50 comprises a combination of a processing circuit 51 and a memory 52. ​​The memory 52 may store program instructions for execution by the processing circuit 51 to perform the operation of the control device 50. The control device 50 comprises a signal interface 53A for inputting the sensor signals S1, S2 and outputting the control signals C1, C2. In the illustrated example, the control device 50 further comprises a signal interface 53B for receiving input data from an input device 54, such as a keyboard, mouse, microphone, touch screen, etc., and for providing output data to a feedback device 55, such as a display, speaker, projector, etc. The above-mentioned program instructions may be supplied to the control device 50 on a computer-readable medium, which may be a tangible (non-transitory) product (e.g., magnetic media, optical disk, read-only memory, flash memory, etc.) or a propagated signal. The processing circuitry may comprise a general-purpose processor, e.g., a microprocessor, microcontroller, CPU, DSP (digital signal processor), GPU (graphics processing unit), etc., or a special-purpose processor, such as an ASIC (application-specific integrated circuit) or FPGA (field-programmable gate array), or any combination thereof. The memory 52 may include volatile and / or non-volatile memory, such as read-only memory (ROM), random-access memory (RAM), or flash memory.

[0069] FIG. 4A is a cross-sectional view of an exemplary irradiation module 22A for use in the dechlorination apparatus 20′ of FIG. 3. The module 22A comprises a casing or housing 220 defining a treatment chamber 221 having one or more inlets or inlet ports 222 (one shown) and one or more outlets or outlet ports 223 (one shown). Influent water enters the treatment chamber 221 through the inlet 222, and effluent water exits the treatment chamber 221 through the outlet 223. In the context of FIG. 3, the inlet 222 is coupled to receive intermediate water W1″ from the connecting fluid line 20B, and the outlet 223 is coupled to provide dechlorinated water W1′ to the connecting fluid line 20A. At least one source 224 of UV radiation (one shown) is disposed within the treatment chamber 221. The UV source 224 is operable to generate UV radiation to irradiate at least a portion of the treatment chamber 221 with a diverging beam, as indicated by the dashed lines in FIG. 4A. The UV radiation thereby interacts with the fluid in the processing chamber 221. The UV source 224 may include any element capable of generating UV radiation, including, but not limited to, a light-emitting diode (LED), a laser diode, a fluorescent lamp, an incandescent lamp, a gas discharge lamp, etc. To reduce power consumption and cost, the UV source 224 may comprise one or more LEDs or laser diodes. LEDs and laser diodes also have a small footprint, a long operating life, and a well-defined emission spectrum. At least one UV sensor 225 (one is shown) is arranged to generate a measurement signal S2 indicative of the UV radiation intensity in the processing chamber 221. The signal value in the signal S2 may be provided in any suitable units, such as a voltage indicative of the incident power or irradiance on the UV sensor 225. In the context of this specification, the measured intensity value may be provided in units provided by the UV sensor 225 or in any other units provided by applying a conversion function to the signal value from the UV sensor 225. The UV sensor 225 may include any element that is responsive to UV radiation, including, but not limited to, a photodiode, a phototransistor, a photoconductive detector, a phototube, a photocell, or the like.The UV sensor 225 may be located anywhere that is directly or indirectly illuminated by the UV source 224. In the illustrated example, the UV sensor 225 is located on the opposite side of the UV source 224. In other examples, the UV sensor 225 is located on the same side as the UV source 224 or is physically combined into the package with the UV source 224.

[0070] The irradiation module 22A may be configured for continuous or intermittent operation. In intermittent operation, water is intermittently introduced into the chamber 221 for treatment. In continuous operation, water is continuously transported through the chamber 221 while being treated. Continuous operation may require greater emission (radiation) power of the UV source 224, but may increase the rate at which the WPA 20 produces conditioned water W2.

[0071] The UV source 224 may be configured to generate UV radiation within a wavelength range of 100-400 nm. UV radiation is largely absorbed by water molecules below 200 nm, and bound chlorine has poor absorption of UV radiation above about 350 nm. Therefore, the UV source 224 may be configured to limit the UV radiation generated to the range of 200-350 nm. In some embodiments, the UV radiation generated is limited to the range of 200-280 nm.

[0072] FIG. 5 is a graph showing the molar adsorption rate 501 of dichloramine (NHCl) and the molar adsorption rate 502 of monochloramine (NHCl) as a function of wavelength. The molar adsorption rate curves 501 and 502 roughly correspond to the photolytic decomposition of each substance as a function of wavelength. In FIG. 5, dichloramine (curve 501) has an increased adsorption rate in the range of 275 to 315 nm, with a maximum at approximately 295 nm, while monochloramine (curve 502) has an increased adsorption rate in the range of approximately 225 to 275 nm, with a maximum at approximately 245 nm. To optimize the chlorine reduction efficiency of module 22A, it is desirable to match the emission spectrum of UV source 224 to the high adsorption rate region of FIG. 5. Three exemplary emission spectra R1, R2, and R3 for UV source 224 are shown as dotted lines in FIG. 5. Spectrum R1 approximately coincides with the maximum of curve 502 at about 245 nm and may result in maximum photodegradation of monochloramine. Spectrum R2 approximately coincides with the maximum of curve 501 at about 295 nm and may result in maximum photodegradation of dichloramine. Spectrum R3 approximately coincides with the intersection of curves 501 and 502 at about 270 nm.

[0073] The choice of wavelength can also affect the absorption curves of dissolved hypochlorite and hypochlorous acid, which may be present in the influent water as free chlorine. Literature data indicate that both substances have broad ranges of high adsorption rates, i.e., from about 220 to 255 nm with a maximum at about 240 nm for hypochlorous acid and from about 265 to 320 nm with a maximum at about 290 nm for hypochlorite.

[0074] Depending on the emission characteristics of the available UV-emitting elements, it may be advantageous to combine at least two UV-emitting elements with different emission spectra within the UV source 224. The emission spectra of the different UV-emitting elements may or may not overlap. In some embodiments, the UV-emitting elements are configured to emit in different wavelength ranges, which may partially overlap or may not overlap. In the example of FIG. 4A, the UV source 224 includes three radiation-emitting elements L1, L2, and L3, e.g., UV-LEDs, configured to generate the emission spectra R1, R2, and R3 of FIG. 5, respectively. In some embodiments, each UV-emitting element is configured to generate an emission spectrum (see R1, R2, and R3 in FIG. 5) with an approximate width (full width at half maximum, FWHM) in the range of 5 to 15 nm.

[0075] The irradiation module 24A may be designed for a feedwater W1 having a particular composition of total chlorine by adapting the UV source 225. For example, in some regions, the feedwater W1 contains low concentrations of dichloramine. The total chlorine may vary significantly between regions. Thus, the UV source 225 may be selected to have emission characteristics appropriate for a particular region, e.g., in terms of output (radiant) power, wavelength of UV radiation, etc.

[0076] As can be appreciated from the above, the irradiation module 22A may include a UV source 224 having two or more UV-emitting elements configured to emit UV radiation at least partially in different wavelength ranges, where the wavelength ranges may be selected to target the degradation of different chlorinated species in the water being dechlorinated. In some embodiments, at least one UV-emitting element is configured to primarily cause the degradation of monochloramine, and at least one UV-emitting element is configured to primarily cause the degradation of free chlorine and dichloramine. This allows for optimization of the UV radiation from the UV source 224. In some embodiments, this is achieved by using a combination of UV-emitting elements emitting in the 240-265 nm range and the 265-290 nm range, respectively.

[0077] In some embodiments, irradiation module 22A may be operated to selectively activate one or more of the UV-emitting elements in UV source 224 based on the expected composition of total chlorine in feedwater W1 to be dechlorinated. In some embodiments, control device 50 automatically and selectively activates one or more of the available UV-emitting elements in UV source 224 based on feedwater content data (see step 601). The content data is made available to control device 50 to indicate the composition of chlorine in the feedwater.

[0078] Currently, UV irradiation is used as a disinfection method for drinking water treatment. The underlying mechanism is that nucleic acids in microorganisms are damaged after absorbing incident UV radiation. Applicant has conducted experiments showing that the radiant (emission) power of the UV source needs to be increased by at least 10 times, and in some cases by at least 15 or 20 times, to decompose chlorine in water in conventional devices configured for water disinfection by UV irradiation.

[0079] Filter module 21A in dechlorination subsystem 20′ of FIG. 3 may be configured as in FIG. 2. However, because irradiation module 22A provides redundancy for filter module 21A, it is contemplated that the internal redundancy of filter module 21A may be eliminated or at least reduced. Thus, in some embodiments, the internal redundancy of filter module 21A is less than 2, e.g., in the range of 1.0 to 1.9, where an internal redundancy of 1.0 or 1.9 means that filter module 21A is designed to remove 100% or 190%, respectively, of the target amount of total chlorine (see step 610 below).

[0080] Elimination or reduction of redundancy can be achieved by eliminating one of the AC filters 100 of FIG. 2 or by reducing the filtering capacity of each AC filter 100 of FIG. 2, for example, by using an AC filter 100 containing a smaller amount of activated carbon 100A. This reduces both the manufacturing and operating costs of the filtering device 21, thereby offsetting the additional cost of the illumination device 22. The cost of the illumination module 22A is currently believed to be comparable to that of a conventional AC filter 100. Considering that the AC filters in the reference example are typically replaced two to three times a year, while the illumination module 22A can have an operational lifespan of several years, this novel concept indeed allows for significant cost savings compared to the reference example in FIG. 2.

[0081] 4B shows an example of a filter module 21A having a single AC filter 100 including a bed (layer) of activated carbon 100A. An inlet line 101 is fluidly connected to the inlet of the AC filter 100, and an outlet line 102 is fluidly connected to the outlet of the AC filter 100. In the example shown, feed water W1 passes through the AC filter 100 to produce intermediate water W1″ (see FIG. 3).

[0082] FIG. 6A is a flowchart of an exemplary method 600 for configuring the dechlorination subsystem 20′, according to one embodiment. Method 600 can be performed by an engineer prior to installing the subsystem 20′ or when designing the subsystem 20′. In step 601, an expected amount of total chlorine in the feedwater W1 (the “design amount”) is obtained. The design amount can be provided by measurement or nominal data. Step 601 may include obtaining detailed content data regarding the chlorine content in the feedwater W1, such as the relationship between educts and conjugates, or the composition of educts and / or conjugates. In step 602, a target amount of total chlorine to be removed from the feedwater W1′ is determined based on the design amount, e.g., to meet predetermined requirements for the dechlorinated water W1′. In step 603, the filtration device 21 is configured to remove the target amount by using activated carbon filtration. For example, the amount of activated carbon 100A may be selected and the flow rate of the feedwater W1 may be adjusted, taking into account the target amount and the selected internal redundancy for the filtration device 21. In step 604, the irradiation device 22 is configured to remove the target amount by UV irradiation. For example, step 604 may include adjusting, for example, the number of UV sources 224, the radiation power, the emission spectrum of the UV sources 224, the size of the chamber 221, etc., taking into account the target amount. In one example, the technician selects a suitable irradiation module 22A to install in the irradiation device 22 from among multiple different irradiation modules 22A. Alternatively, if a single pre-configured irradiation module 22A is available, the technician can adjust the radiation power of the UV source 225 taking into account the target amount. Those skilled in the art will understand that the irradiation device 22A may be configured taking into account the detailed content data described above.

[0083] FIG. 6B is a flowchart of an exemplary procedure 610 for operating the WPA 20 of FIG. 3 . Procedure 610 may be performed by control device 50 (FIG. 3). In step 611, feed water W1 is entered into WPA 20. In step 612, filtration device 21 is operated according to predetermined settings to pass the feed water through activated carbon in filter module 21A. The predetermined settings may be provided by step 603 of method 600. In step 613, irradiation device 22 is operated to receive intermediate water W1″ from filtration device 21 and irradiate W1″ with UV radiation according to predetermined settings. The predetermined settings may be provided by step 604 of method 600. In step 614, main subsystem 20″ is operated to receive dechlorinated water W1′ and process it into conditioned water W2 according to predetermined settings. Thus, step 614 prepares W2 based on W1′. Step 614 may be performed according to conventional practice depending on the type of water purification equipment in main subsystem 20''. In step 615, conditioned water W2 is provided for use in the medical procedure. Conditioned water W2 may be provided as a continuous stream from WPA 20 or in batches.

[0084] It should be noted that, in addition to the other benefits described herein, the illumination device 22 can prevent a sudden increase in chlorine concentration in the feedwater W1 (a "chlorine spike") from affecting the dechlorinated water W1". In some regions, it is not uncommon for the total chlorine in the feedwater W1 to occasionally exceed the design amount (see step 601) due, for example, to instabilities in the water preparation plant that produces W1. During a chlorine spike, the intermittent water W1" may contain an elevated chlorine concentration, which will be reduced to an acceptable level by the illumination device 22.

[0085] The applicant has found that it is possible to monitor the condition of the irradiation device 22 based on the measurement signal S2 (FIGS. 3 and 4A). Experiments have shown that the signal S2 correlates with the radiation power of the UV source. Experiments have also shown that the signal S2 is affected by the condition of the chamber 221. For example, deposits on the UV source 224 and the UV sensor 225 in the chamber 221 can degrade the signal S2. Therefore, the control device 50 can operate to detect the need for maintenance of the irradiation device 22 in response to the signal S2.

[0086] FIG. 6C illustrates an exemplary method 620 for monitoring the operational status of the illumination device 22, according to one embodiment. Method 610 may be performed by the control device 50 (FIG. 3). In method 620, the WPA 20 is operated according to procedure 610. During operation of the WPA 20, steps 621-622 are performed, e.g., at regular time intervals, to monitor the performance of the illumination device 22. In step 621, characteristic values ​​are derived from one or more measurements in the measurement signal S2. Each characteristic value represents the UV radiation intensity on the UV sensor 225. For example, the characteristic value may be provided by a single measurement, a time average of multiple measurements, a low-pass filtered value, or the like. The characteristic value may be converted into units of UV radiation intensity. Alternatively, the characteristic value may be provided in units provided by the UV sensor 225, e.g., voltage. The characteristic values ​​from step 621 form a time sequence of values. In step 622, the time sequence of values ​​is evaluated in relation to a detection criterion for detecting a fault in the illumination device 22. If the detection criteria are not met, operation of the WPA 20 continues, and step 622 causes step 621 to be executed at a future time. If the detection criteria are met, step 622 causes operation of the WPA 20 to be stopped (via step 623) and an alert to be generated (via step 624). The alert indicates a malfunction of the illumination device 22. The malfunction may be, for example, that the radiation power of the UV source 224 is too low or that there is too much deposit or other fouling in the chamber 221. In step 624, the feedback device 54 (FIG. 3) may be operated to provide an alarm signal, information regarding the cause of the malfunction, or instructions to an operator. For example, the operator may be instructed to inspect or perform maintenance on the illumination device 22.

[0087] During such maintenance, the illumination module 22A may be replaced and / or repaired. Additionally, the performance of the filtering device 21 may be evaluated during maintenance by taking a sample of W1″ downstream of the filtering device 21 and analyzing the sample for chlorine. If the total chlorine rises, the filter module 21A of the filtering device 21 may be replaced. Alternatively, whenever the illumination module 22A requires maintenance, the filter module 21A may be replaced with a default. It will be appreciated that the number of samples that need to be taken and analyzed is significantly reduced compared to the reference example of FIG. 2.

[0088] It is understood that the method 620 is performed under the assumption that the filtering device 21 is functioning properly.

[0089] In some embodiments, step 622 includes comparing each characteristic value to an intensity limit, and the detection criterion may be met if a predetermined number (N), where N≧1, of characteristic values ​​are below the intensity limit. The intensity limit may be set to ensure that if a characteristic value exceeds the intensity limit, the illumination device 22 is operable to eliminate the target amount (see step 602). The intensity limit may be determined in a validation procedure in which the illumination module 22A is tested under well-controlled conditions. The validation procedure may include measuring the characteristic value for source water having a reference concentration of total chlorine and for one or more radiant powers of the UV source, and analyzing the chlorine content in the treated water.

[0090] Depending on the type of fault, the characteristic value may change slowly or quickly. Gradual fouling of the chamber 221 or gradual deterioration of the UV source 224 may result in a slow change, while a complete loss of radiant power of one or more radiation-emitting elements in the UV source may result in a rapid change. Thus, the control device may be configured to output different information / commands depending on the nature of the detected change.

[0091] After significant experimentation, the applicant identified an opportunity for online monitoring of the performance of the filtration device 21, specifically to detect the occurrence of channeling. Figure 8A shows example experimental results obtained for an illumination device configured to emit 280 nm UV radiation. Water containing 0, 2, 4, 6, and 8 ppm of free chlorine was supplied to the illumination device, and the average signal level (here, voltage) of the measurement signal S2 was measured. Thus, Figure 8A shows the measured signal levels for different amounts of free chlorine in the influent water. Figure 8A includes a trend line (dashed line) that is a polynomial fit to the measurement data. As can be seen, the signal level of S2 decreases monotonically with increasing amounts of free chlorine. This decrease is the result of the absorption of UV radiation by free chlorine. Similar results would be expected for monochloramine (Figure 5) if the wavelength of the UV radiation was appropriately matched to the monochloramine adsorption rate. Channeling within filtration device 21 is expected to rapidly increase the total chlorine concentration downstream of filtration device 21, for example, from less than 0.1 ppm to 2-4 ppm depending on the total chlorine concentration in feed water W1. Considering Figure 8A, such an increase results in a detectable step change in measurement signal S2.

[0092] The performance of the above-described irradiation device to remove free chlorine from the influent water was also tested. The free chlorine concentration was measured simultaneously in the influent water to the operating irradiation device and in the effluent water from the operating irradiation device. Experiments were conducted with varying free chlorine concentrations in the influent water. The results are shown in the graph in FIG. 8B. As shown, the free chlorine concentration dramatically decreases with operation of the irradiation device 22. Similar results are expected for monochloramine and dichloramine. Given the constraints of the experimental setup, it is predicted that the total chlorine concentration in the effluent water can be reduced to 0.1 ppm or less by directly optimizing the radiation power and / or wavelength of the UV radiation of the UV source in the irradiation device 22, as described above with reference to FIG. 5, for example. This experiment demonstrates that, as expected, the irradiation device 22 can effectively remove chlorine from the supply water W1.

[0093] FIG. 6D illustrates an exemplary method 630 for monitoring the operating status of the filtering device 21 according to an embodiment. The method 630 may be performed by the control device 50 (FIG. 3). The method 630 will be described first for the illumination module 22A of FIG. 9A, which is similar to the module 22A of FIG. 4A. In the method 630, the WPA 20 is operated according to procedure 610. During operation of the WPA 20, step 631 is performed, for example, at regular time intervals, to detect a decrease in a step change in the measurement signal S2. FIG. 9B illustrates an example of such a step change that occurs when a channel is formed in the filtering device 21 at time tb, causing the device 21 to provide water with a high chlorine concentration to the illumination device 22. The step change may be detected in any suitable manner in step 631, for example, by detecting that the measured intensity falls below an intensity threshold T1, as shown in FIG. 9B. The threshold T1 may be predefined or set relative to a dynamic reference level, which may be given by, for example, an average of the most recently measured intensity values ​​in S2. Thus, in some embodiments of step 631, a reference level is determined at the current time as a function of the previous signal value at S2, a threshold T1 is set for the reference level, and the signal level at S2 at the current time is compared to T1. Alternatively or additionally, a step change may be detected when the derivative of the measured intensity exceeds a derivative threshold. The derivative of the measured intensity may be determined by the derivative of signal S2. The measured intensity may be given by the characteristic value described above (step 621 in FIG. 6C). Step 631 may also require that the measured intensity remain below T1 for a predetermined period of time before a step change is considered to be detected.

[0094] If no step change is detected in step 631, operation of the WPA continues, and step 633 causes method 630 to execute step 631 at a future time. If a step change is detected, step 633 causes operation of WPA 20 to cease (step 634) and generate an alert (step 635). In step 635, feedback device 54 (FIG. 3) may be operated to provide an alarm signal, information regarding the cause of the operation cease, or instructions to an operator. For example, the operator may be instructed to perform maintenance on filtering device 21.

[0095] Method 630 provides a significant technological advancement because it allows for online monitoring of the performance of filtration device 21. This effectively eliminates the need to take and analyze intermediate water samples (see W1 in FIGS. 3 and 4A).

[0096] It should be noted that the intermittent spikes in chlorine concentration in the water supply W1 discussed above may be visible in the measurement signal S2. Method 630 may or may not be designed to distinguish between signal features resulting from intermittent spikes in the water supply W1 and step changes caused by channeling, for example, based on differences in derivative and / or amplitude and / or duration.

[0097] As indicated by the dashed box in FIG. 6D , method 630 can include step 632 of monitoring a further measurement signal S2′ for detecting a step change. Step 632 is based on insight derived from the experimental data of FIG. 8B . The experimental data show that the concentration of free chlorine in the effluent (squares in FIG. 8B ) monotonically decreases with a decrease in the concentration of free chlorine in the influent (circles in FIG. 8B ). Considering the data of FIGS. 8A-8B together, this means that a step increase in the chloride concentration of the influent to illumination device 22 caused by channeling within filtration device 21 not only results in a step decrease in the signal level at S2, but also in an increase in the chloride concentration of the effluent. By detecting this concentration increase, improved reliability of channeling detection can be achieved.

[0098] The signal S2' may be provided by the illumination module 22A, as shown in FIG. 10A. The further UV sensor 225' is arranged downstream of the chamber 221 to receive the UV radiation generated by the further UV source 224'. In the illustrated example, the further UV source 224' and the further UV sensor 225' are arranged in a further chamber 221' defined by a further housing 220' and fluidly connected to the output port of the housing 220. The illustrated arrangement is given by way of example only, and the further UV sensor 225' may be arranged anywhere that is directly or indirectly illuminated by the further UV source 224'. The further housing 220' may be a separate measurement unit or an integrated part of the piping extending from the outlet. The further UV source 224' may be, but does not necessarily have to be, identical to the UV source 224. It is conceivable that the UV source 224' emits UV radiation at a (partially) different wavelength than the UV source 224. Compared to UV source 224, the radiation power of further UV source 224' may be lower because its purpose is not dechlorination but rather measurement of the total residual chloride in the water that has passed through chamber 221. FIG. 10B shows an example of a step change decrease in measurement signal S2' as a result of channel formation in filtration device 21 at time tb. As shown, there may be a delay from time tb until the water with increased chloride concentration reaches chamber 221'. The step change in signal S2' may be slower than the step change in signal S2, depending on the degree of mixing in chamber 221. After channel formation, chamber 221 likely contains water from both before and after channel formation. As mixing in chamber 221 increases, a more gradual decrease (slower step change) in signal level may be detected by UV sensor 225' as water flows from chamber 221 into chamber 221'.

[0099] Step 632, similar to step 631, may detect a decrease in the step change. In some embodiments, a step change is detected when the measured intensity of signal S2' falls below intensity threshold T2, as shown in FIG. 10B. Similar to threshold T1, threshold T2 may be predefined or set with respect to a dynamic reference level. Step 633 may also require that the measured intensity remain below T2 for a predetermined period of time before a step change is considered detected.

[0100] Step 633 may be configured to logically combine the results of steps 631 and 632 to determine whether method 630 should proceed to step 634. This may reduce the risk of a false positive in the determination by step 633.

[0101] In some embodiments, step 633 applies a logical AND between the results of steps 631 and 632, such that step 633 proceeds to step 634 only if a time-synchronized step change is detected in both signals S2, S2′. For example, step 633 may require that a step change occur in S2 and S2′ within a predetermined period of time. In other embodiments, step 633 applies a logical OR between the results of steps 631 and 632, such that step 633 proceeds to step 634 if a step change is detected in at least one of signals S2 and S2′ within a predetermined period of time. It is also contemplated that step 633 may switch between applying a logical AND or a logical OR. In one example, step 633 may use a logical AND by default and switch to an OR if the confidence in the detection by step 631 or step 632 is low. For example, step 631 and / or step 632 may provide a confidence value for each detected step change. The confidence value may be given by the magnitude of the signal decrease during the step change and / or the derivative of the step change.

[0102] FIG. 7 is a schematic diagram of an exemplary main subsystem 20″. FIG. 7 is provided merely to provide further context and is not intended to limit the present disclosure in any way. Main subsystem 20″ includes an inlet 120A for dechlorinated water W1′ and an outlet 120B for conditioned water W2. An inlet line 121 extends from inlet 120A to a tank 122 for intermediate storage of the dechlorinated water. A connecting line 123 extends from tank 122 to a feed side 125A of an RO module 125. RO module 125 is of conventional construction and includes an RO membrane 125′ that separates RO module 125 into a feed side 125A and a permeate side 125B. RO membrane 125′ may be a semipermeable membrane. RO module 125 is configured to remove impurities, such as microorganisms, pyrogens, and ionic substances, from the dechlorinated water by reverse osmosis. A fluid pump 124 is disposed in connecting line 123. A drain line 126 extends from the feed side 125A to a drain 127. In the illustrated example, an on-off valve 128 is disposed in the drain line 126, and a return line 129 extends from the drain line 126 upstream of the valve 128 to a connecting line 123 downstream of the fluid pump 124. A further fluid pump 130 is disposed in the return line 129. A connecting line 131 extends from the permeate side 125B to a post-treatment module 132.

[0103] During operation, pump 124 is activated to pump dechlorinated water from tank 122 to feed side 125A of RO module 125, applying sufficient pressure to overcome osmotic pressure. The influent stream of dechlorinated water, referred to as feedwater, is thereby split into a wastewater stream on feed side 125A and a purified water stream (permeate) on permeate side 125B. In a first mode of operation, valve 128 is open, and the wastewater stream is conveyed along drain line 126 to drain 127. In a second mode of operation, valve 128 is closed, and pump 130 is activated, resulting in the wastewater stream being recirculated back through connecting line 123 and pumped back to RO module 125. The recirculation increases the feed flow to RO module 125, reducing scaling and fouling of RO membrane 125'. RO module 125 may be switched between the first and second modes of operation as needed. In a third mode of operation, the wastewater is split into a wastewater stream that is recirculated by pump 130 and a drain water stream that is simultaneously passed to drain 127 by opening valve 128 to an appropriate extent or at appropriate intervals. The resulting permeate is conveyed in connecting line 131 to post-treatment module 132.

[0104] Post-treatment module 132 is configured to polish the permeate to further remove ions from the permeate, resulting in conditioned water W2, which is provided to outlet 120B on outlet line 133. The permeate is polished using a polishing device such as an electrodeionization (EDI) device, an ion exchanger device such as a mixed bed filter device, or an RO module. A mixed bed filter device includes a column or vessel having mixed bed ion exchange material.

[0105] Post-treatment module 132, or another module downstream of post-treatment module 132, may also include ultrafiltration to remove bacteria and endotoxins, in which case one or more ultrafilters may be utilized.

[0106] While the subject matter of this disclosure has been described in connection with what are presently considered to be the most practical embodiments, it is to be understood that the subject matter of this disclosure is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements that come within the meaning and range of equivalents of the appended claims.

[0107] Additionally, although operations are shown in the figures in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown, or in sequential order, or that all of the shown operations be performed, to achieve desirable results.

Claims

1. 1. An apparatus for preparing water for use in medical treatment of the human or animal body (P), said apparatus being configured to receive a supply of water (W1) from a water source (10), a filtration device (21) configured to effectively remove chlorine from said supply water by use of one or more activated carbon filters (100); an irradiation device (22) configured to effectively remove the chlorine in the supply water (W1) by ultraviolet (UV) irradiation; The filtration device (21) and the irradiation device (22) are connected in series to sequentially treat the feed water (W1) into dechlorinated water (W1'); The apparatus is configured to provide conditioned water (W2) for use in the medical procedure based on the dechlorinated water (W1').

2. 2. The apparatus of claim 1, wherein the irradiation device (22) comprises a casing (220) defining a treatment chamber (221), an inlet (222) to the treatment chamber (221) for influent water, and an outlet (223) from the treatment chamber (221) for effluent water, and the irradiation device (22) further comprises at least one source (224) of UV radiation arranged to irradiate at least a portion of the treatment chamber (221).

3. 3. The apparatus of claim 2, wherein the irradiation device (22) further comprises at least one sensor (225) configured to generate a measurement signal (S2) indicative of UV radiation intensity in the treatment chamber (221), and the apparatus further comprises a control device (50) configured to receive the measurement signal (S2) and monitor operation of at least one of the irradiation device (22) or the filtering device (21) based on the measurement signal (S2).

4. 4. The apparatus of claim 3, wherein the control device (50) is configured to evaluate the UV radiation intensity in the processing chamber (221) with respect to an intensity limit based on the measurement signal (S2) and to generate a warning indicating a failure of the irradiation device (22) if the UV radiation intensity falls below the intensity limit.

5. The apparatus of claim 4 , wherein the failure comprises at least one of a reduction in radiant power of the at least one source of UV radiation (224) or contamination within the processing chamber (221).

6. 6. The apparatus of claim 4 or 5, wherein the intensity limit corresponds to the irradiation device (22) being operable to effectively remove the chlorine in the supply water (W1).

7. 7. The apparatus of claim 2, wherein the at least one source of UV radiation comprises a light emitting diode or a laser diode.

8. 8. The apparatus of claim 2, wherein the at least one source (224) of UV radiation comprises a first radiation emitting element (L1) and a second radiation emitting element (L2), the first and second radiation emitting elements (L1, L2) being configured to emit UV radiation in different wavelength ranges.

9. 9. The apparatus of claim 8, wherein the control device (50) is configured to activate the first radiation-emitting element (L1), the second radiation-emitting element (L2), or both the first and second radiation-emitting elements (L1, L2) for the removal of the chlorine in the supply water (W1).

10. 10. The apparatus of claim 8 or 9, wherein the control device (50) is configured to selectively activate at least one of the first or second radiation emitting elements (L1, L2) based on input data representing the composition of the chlorine in the supply water (W1).

11. 11. The apparatus of claim 8, wherein the first radiation-emitting element (L1) is configured to preferentially remove monochloramine over free chlorine and dichloramine, and the second radiation-emitting element (L2) is configured to preferentially remove free chlorine and dichloramine over monochloramine.

12. 12. Apparatus according to any one of claims 8 to 11, wherein the first radiation emitting element (L1) is configured to generate UV radiation having a peak in a first wavelength range of 240 to 265 nm and the second radiation emitting element (L2) is configured to generate UV radiation having a peak in a second wavelength range of 265 to 290 nm.

13. 13. Apparatus according to any one of claims 2 to 12, wherein the at least one source (224) of UV radiation is configured to generate UV radiation in the wavelength range of 100 to 400 nm, preferably in the wavelength range of 200 to 325 nm.

14. 14. Apparatus according to any one of claims 2 to 13, wherein the irradiation device (22) is configured to operate with a continuous flow of water through the treatment chamber (221) from the inlet (222) to the outlet (223).

15. 15. The apparatus according to claim 1, wherein the control device (50) is configured to detect channel formation in the one or more activated carbon filters (100) of the filtering device (21) based on the measurement signal (S2) and to generate a warning signal in response to the detection of the channel formation.

16. 16. The apparatus of claim 15, wherein the control device (50) is configured to evaluate the measurement signal (S2) for detection of a decrease in a step change in the measurement signal (S2) upon detection of the channel formation.

17. 17. Apparatus according to claim 16, wherein the control device (50) is configured to detect the decrease in the step change by comparing the signal level in the measurement signal (S2) with a threshold value (T1).

18. 18. The apparatus of claim 17, wherein the control device (50) is configured to determine a reference level at a current time point as a function of a previous signal value in the measurement signal (S2), to set the threshold value with respect to the reference level, and to compare the signal level in the measurement signal (S2) at the current time point with the threshold value (T1).

19. 19. The apparatus of claim 15, wherein the irradiation device (22) comprises a further source (224') of UV radiation and a further sensor (225') arranged downstream of the at least one source (224) and the sensor (225), the further sensor (225') being configured to generate a further measurement signal (S2') indicative of the UV radiation intensity received from the further source (224'), and the control device (50) is configured to detect the channel formation based on the measurement signal (S2) and the further measurement signal (S2').

20. 20. The apparatus of claim 19, wherein the control device (50) is configured to evaluate the further measurement signal (S2') for detection of a decrease in a further step change of the further measurement signal (S2') relative to the detection of the channel formation.

21. 21. The apparatus of claim 20, wherein the control device (50) is configured to generate the warning signal if the further step change decrease of the further measurement signal (S2') is detected in time synchronization with a corresponding step change decrease of the measurement signal (S2).

22. 22. Apparatus according to any one of the preceding claims, wherein the filtering device (21) is arranged upstream of the illumination device (22).

23. 23. The apparatus of claim 1, wherein the filtration device (21) and the irradiation device (22) are included in a pre-treatment subsystem (20'), and the apparatus further comprises a main subsystem (20'') configured to receive the dechlorinated water (W1') from the pre-treatment subsystem (20') and to process the dechlorinated water (W1') to produce the conditioned water (W2).

24. 24. The apparatus of claim 23, wherein the main subsystem (20'') comprises at least one of a reverse osmosis device or an ion exchange device.

25. 25. Apparatus according to any one of the preceding claims, wherein the filtering device (21) and the irradiation device (22) are connected in series without any intervening treatment equipment for removing chlorine.

26. 26. The device according to any one of the preceding claims, configured to supply the conditioned water (W2) to a dialysis machine (30).

27. 27. Apparatus according to any one of the preceding claims, wherein the filtering device (21) comprises a single activated carbon filter (100) configured to effectively remove the chlorine in the supply water (W1).

28. 28. The apparatus of claim 1, wherein the irradiation device (22) is configured to remove a first target amount of chlorine from the supply water (W1) and the filtration device (21) is configured to remove a second target amount of chlorine from the supply water (W1), the second target amount being at least equal to the first target amount and less than twice the first target amount.

29. 29. A system comprising the apparatus (20) for preparing water according to any one of claims 1 to 28, and a dialysis machine (30) fluidly connected to receive the conditioned water (W2) from the apparatus (20) for preparing water.

30. 1. A method for preparing water for use in medical treatment of the human or animal body, comprising: receiving a supply of water from a water source (611); operating (612, 613) a filtration device (21) and an irradiation device (22) connected in series to sequentially process the feed water (W1) into dechlorinated water (W1'), wherein the filtration device is configured to effectively remove chlorine from the feed water by filtration through activated carbon and the irradiation device is configured to effectively remove chlorine from the feed water by ultraviolet (UV) irradiation; providing conditioned water for use in the medical procedure based on the dechlorinated water (615); A method comprising:

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