AU2017234381A1

AU2017234381A1 - Disinfection monitoring system and method

Info

Publication number: AU2017234381A1
Application number: AU2017234381A
Authority: AU
Inventors: Terry MAHONY; Adrian MALYON
Original assignee: Sydney Water Corp
Current assignee: Sydney Water Corp
Priority date: 2016-03-16
Filing date: 2017-03-16
Publication date: 2018-10-11
Also published as: WO2017156583A1

Abstract

Disclosed herein is an apparatus (100) for field monitoring disinfection of a fluid system. The apparatus comprises an inlet (102) for connection to a fluid system undergoing disinfection, and instruments (108, 109) for detecting parameters indicative of turbidity T and disinfectant concentration D. A controller (112) is associated with the instruments (108, 109) and is configured to output a signal indicative of successful disinfection of the fluid system if detected values of disinfectant concentration D and turbidity T satisfy a predetermined criteria.

Description

"Disinfection monitoring system and method"

Cross-reference [0001] Incorporated herein by way of reference is the entire disclosure of Australian Patent Application No. 2016900986, filed 16 March 2016.

Technical Field [0002] The present disclosure relates generally to monitoring of a fluid and in particular to an apparatus and method for monitoring disinfection of a fluid system. The apparatus and method have been developed primarily for monitoring disinfection of potable water and recycled water assets and will be described hereinafter with reference to this application. However, it will be appreciated that the apparatus and method are not limited to these applications and may also be used in other applications.

Background [0003] When new pipelines are laid they need to be cleaned and disinfected prior to use. Additional disinfection processes may also be required during the lifetime of a pipeline, for example after repairs to the pipeline.

[0004] To disinfect a pipeline, the pipeline is initially flushed and then filled with a disinfectant. Traditionally, water containing high levels of chlorine is used as the disinfectant. While effective and still widely used, in some applications chlorine treatment is being replaced with safer and faster-acting alternatives such as ozone.

[0005] Testing to determine whether disinfection has been achieved typically involves taking discrete samples of the water contained in the pipeline undergoing treatment and either sending the water samples to a laboratory for testing and/or testing the water samples in the field with portable meters to determine whether one or more parameters falls within the relevant standards of disinfection.

[0006] The use of a laboratory for testing of water samples is unsuitable for situations where the sample degrades before testing. For example, when measuring samples containing ozone using a colorimeter, a significant proportion of ozone may have decayed into undetectable oxygen before testing due to the time taken for collection, delivery and preparation of the sample.

[0007] Many portable meters can be complicated to use and may provide inaccurate readings when used by an inexperienced operator. Known portable meters are also not adapted to collect and test a water sample in a single step, but rather require an operator to manually collect a water sample from the pipeline, conduct any necessary pre-testing preparation of the sample and deliver the sample to the portable meter for testing. As with laboratory testing, the time involved with these multiple steps can cause the sample to degrade before it can be tested by portable meters. Also, portable meters often require multiple sampling steps and frequent calibration involving specialty standards.

[0008] The use of portable meters also often relies on the operator manually transcribing the readings and other associated information such as location, date and time, to paper before the information is keyed into a database, which allows for errors in the recording/transcription of readings and other data. Furthermore, in the event that a reading falls outside the agreed standards of disinfection, further sampling and testing are required until such time that the reading falls within the agreed standard, causing delays in determining when the pipeline has achieved disinfection.

[0009] Any discussion of documents, acts, materials, devices, articles or the like which has been included in the present specification is not to be taken as an admission that any or all of these matters form part of the prior art base or were common general knowledge in the field relevant to the present disclosure as it existed before the priority date of each claim of this application.

Summary [0010] Throughout this specification the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element, integer or step, or group of elements, integers or steps, but not the exclusion of any other element, integer or step, or group of elements, integers or steps.

[0011] Disclosed herein is an apparatus for field monitoring disinfection of a fluid system undergoing a disinfection process, the apparatus comprising: an inlet for connection to a fluid system undergoing a disinfection process; an instrument for detecting a parameter indicative of turbidity of a fluid flow received from the inlet; an instrument for detecting a parameter indicative of concentration of a disinfectant in the fluid flow received from the inlet; and a controller associated with the instrument for detecting a parameter indicative of turbidity and the instrument for detecting a parameter indicative of concentration of the disinfectant, the controller being configured to output a signal indicative of successful disinfection of the fluid system if detected values of the parameter indicative of turbidity and of the parameter indicative of concentration of the disinfectant satisfy a predetermined criteria for successful disinfection of a target microorganism.

[0012] The predetermined criteria may comprise both: the detected values of the parameter indicative of turbidity remaining below a maximum predetermined value, and the detected values of the parameter indicative of concentration of the disinfectant remaining above a minimum predetermined value, for at least a predetermined period of time.

[0013] The controller may be adapted to receive one or more inputs relating to: the system undergoing the disinfection process, applicable regulatory requirements, source of the fluid, end use of the fluid, target microorganism(s) of the disinfection, and/or type of disinfectant used in the disinfection process; and the predetermined criteria may be calibrated based on the one or more inputs. The predetermined criteria may account for an effect of the magnitude of the detected values of the parameter indicative of concentration of the disinfectant on the time required for successful disinfection of the target microorganism(s), such that higher detected values of the parameter indicative of concentration of the disinfectant may cause the signal indicative of successful disinfection of the fluid system to be output sooner and lower detected values of the parameter indicative of concentration of the disinfectant may cause the signal indicative of successful disinfection of the fluid system to be output later. The predetermined criteria may account for an effect of the magnitude of the detected values of the parameter indicative of turbidity on the time required for successful disinfection of the target microorganism(s), such that higher detected values of the parameter indicative of turbidity may cause the signal indicative of successful disinfection of the fluid system to be output later and lower detected values of the parameter indicative of turbidity may cause the signal indicative of successful disinfection of the fluid system to be output sooner. Similarly, the predetermined criteria may account for the effect of temperature of the fluid and/or pH of the fluid on to the time required for successful disinfection of the target microorganism(s). The apparatus may comprise a thermometer and/or a pH sensor/meter and may be configured to measure the temperature and/or pH of the fluid at the commencement of disinfection monitoring and/or intermittently during disinfection monitoring.

[0014] The apparatus may be configured to use the detected values of the or each said parameter to determine a cumulative disinfecting effect of the disinfection process, wherein the signal indicative of successful disinfection of the fluid system is output when the cumulative disinfecting effect determined is sufficient to successfully disinfect the target microorganism(s).

[0015] The apparatus may further comprise an instrument for determining a location of the apparatus, for example a global positioning system (GPS) device.

[0016] The apparatus may further comprise a transmitter for transmitting over a communications network, such as a mobile network, a WiFi network, the Internet and/or a local or wide area network, data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of the parameter indicative of concentration of the disinfectant; a location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system. In some embodiments, the transmitter may also act as a receiver for the instrument for determining the location of the apparatus.

[0017] The apparatus may further comprise a data storage device for storing data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of the parameter indicative of concentration of the disinfectant; the location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system.

[0018] The parameter indicative of turbidity may be any suitable measure of turbidity, including turbidity itself measured in Nephelometric Turbidity Units (NTU) or equivalent.

[0019] The parameter indicative of concentration of the disinfectant may be any suitable measure indicative of concentration. For example, the parameter indicative of concentration of the disinfectant may be oxidation-reduction potential (ORP). The minimum predetermined value of ORP may vary depending on a number of factors, such as the system undergoing disinfection, the type of fluid carried by the system, and/or any applicable regulatory requirements.

Depending on such factors, the minimum predetermined value of ORP may be at least 500 mV or at least 600 mV or at least 700 mV or at least 750 mV.

[0020] Similarly, the maximum predetermined value of the parameter indicative of turbidity and/or the predetermined period of time may also vary depending on various factors, such as the system undergoing disinfection, the type of fluid carried by the system, and/or any applicable regulatory requirements. Depending on such factors, the maximum predetermined value of the parameter indicative of turbidity may be a value indicating a turbidity of less than around 5 NTU or less than around 3 NTU or less than around 2 NTU. Depending on the same factors, and/or others such as the detected values of the parameter indicative of concentration of the disinfectant, temperature of the fluid and/or pH of the fluid the predetermined period of time may be at least 1 minute, at least 90 seconds or at least 2 minutes.

[0021] It will be appreciated that the apparatus may be used to monitor disinfection of a fluid system associated with any one of a variety of fluids. For example, the apparatus may be used to monitor disinfection of a fluid system for raw water, recycled water, or waste water (e.g. tertiary effluent), or fluid systems associated with cooling towers or swimming pools or food and beverage production or distribution systems. The fluid system may comprise one or more items selected from the group consisting of: one or more pipelines, one or more tanks or reservoirs, one or more filters, one or more valves, one or more manifolds or distribution blocks or pumps, any other component of a water distribution system that requires disinfection, or any combination thereof.

[0022] Also disclosed herein is an apparatus for field monitoring disinfection of a fluid system undergoing a disinfection process, the apparatus comprising: an inlet for connection to a fluid system undergoing a disinfection process; an instrument for detecting a parameter indicative of concentration of a disinfectant in the fluid flow received from the inlet, the parameter being oxidation-reduction potential (ORP) of the fluid flow received from the inlet; and a controller associated with the instrument for detecting ORP, the controller being configured to output a signal indicative of a successful disinfection of the fluid system if the detected values of ORP satisfy a predetermined criteria for successful disinfection of a target microorganism.

[0023] The predetermined criteria may comprise the detected values of ORP remaining above a minimum predetermined value for at least a predetermined length of time.

[0024] The controller may be adapted to receive one or more inputs relating to: the system undergoing the disinfection process, applicable regulatory requirements, source of the fluid, end use of the fluid, target microorganism(s) of the disinfection, and/or type of disinfectant used in the disinfection process; and the predetermined criteria may be calibrated based on the one or more inputs. The predetermined criteria may account for an effect of the magnitude of the detected values of the parameter indicative of concentration of the disinfectant on the time required for successful disinfection of the target microorganism(s), such that higher detected values of the parameter indicative of concentration of the disinfectant may cause the signal indicative of successful disinfection of the fluid system to be output sooner and lower detected values of the parameter indicative of concentration of the disinfectant may cause the signal indicative of successful disinfection of the fluid system to be output later. The predetermined criteria may account for an effect of the magnitude of the detected values of the parameter indicative of turbidity on the time required for successful disinfection of the target microorganism(s), such that higher detected values of the parameter indicative of turbidity may cause the signal indicative of successful disinfection of the fluid system to be output later and lower detected values of the parameter indicative of turbidity may cause the signal indicative of successful disinfection of the fluid system to be output sooner. Similarly, the predetermined criteria may account for the effect of temperature of the fluid and/or pH of the fluid on to the time required for successful disinfection of the target microorganism(s). The apparatus may comprise a thermometer and/or a pH sensor/meter and may be configured to measure the temperature and/or pH of the fluid at the commencement of disinfection monitoring and/or intermittently during disinfection monitoring.

[0025] The apparatus may be configured to use the detected values of the or each said parameter to determine a cumulative disinfecting effect of the disinfection process, wherein the signal indicative of successful disinfection of the fluid system is output when the cumulative disinfecting effect determined is sufficient to successfully disinfect the target microorganism(s).

[0026] The apparatus may further comprise an instrument for detecting a parameter indicative of turbidity of a fluid flow received from the inlet and the controller may be responsive to same. The controller may be configured to output the signal indicative of successful disinfection of the fluid system if both: the detected values of the parameter indicative of turbidity remain below a maximum predetermined value; and the detected values of ORP remain above a minimum predetermined value, for at least a predetermined period of time.

[0027] The parameter indicative of turbidity may be any suitable measure of turbidity, including turbidity itself measured in NTU or equivalent.

[0028] The minimum predetermined value of ORP may vary depending on a number of factors, such as the system undergoing disinfection, the type of fluid carried by the system, and/or any applicable regulatory requirements. Depending on such factors, the minimum predetermined value of ORP may be at least 500 mV, at least 600 mV, at least 700 mV or at least 750 mV.

[0029] Similarly, the maximum predetermined value of the parameter indicative of turbidity and/or the predetermined period of time may also vary depending on various factors, such as the system undergoing disinfection, the type of fluid carried by the system, and/or any applicable regulatory requirements. Depending on such factors, the maximum predetermined value of the parameter indicative of turbidity may be a value indicating a turbidity of less than around 5 NTU or less than around 3 NTU or less than around 2 NTU. Depending on the same factors, and/or others such as the detected values of ORP, temperature of the fluid and/or pH of the fluid, the predetermined period of time may be at least 1 minute, at least 90 seconds or at least 2 minutes.

[0030] It will be appreciated that the apparatus may be used to monitor disinfection of a fluid system associated with any one of a variety of fluids. For example, the apparatus may be used to monitor disinfection of a fluid system for raw water, recycled water, or waste water (e.g. tertiary effluent), or fluid systems associated with cooling towers or swimming pools or food and beverage production or distribution systems. The fluid system may comprise one or more items selected from the group consisting of: one or more pipelines, one or more tanks or reservoirs, one or more filters, one or more valves, one or more manifolds or distribution blocks or pumps, any other component of a water distribution system that requires disinfection, or any combination thereof.

[0031] The apparatus may further comprise an instrument for determining a location of the apparatus, for example a global positioning system (GPS) device.

[0032] The apparatus may further comprise a transmitter for transmitting over a communications network, such as a mobile network, a WiFi network, the Internet and/or a local or wide area network, data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of ORP; a location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system. In some embodiments, the transmitter may also act as a receiver for the instrument for determining the location of the apparatus.

[0033] The apparatus may further comprise a data storage device for storing data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of ORP; the location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system.

[0034] Also disclosed herein is a method of field monitoring disinfection of a fluid system undergoing a disinfection process, the method comprising: connecting an apparatus for field monitoring disinfection of a fluid system to a fluid system undergoing a disinfection process such that the apparatus receives a fluid flow from the fluid system; detecting a parameter indicative of turbidity of the fluid flow; detecting a parameter indicative of concentration of a disinfectant in the fluid flow; and outputting a signal indicative of successful disinfection of the fluid system if detected values of the parameter indicative of turbidity and of the parameter indicative of concentration of the disinfectant satisfy a predetermined criteria for successful disinfection of a target microorganism.

[0035] The predetermined criteria may comprise both: the detected values of the parameter indicative of turbidity remaining below a maximum predetermined value, and the detected values of the parameter indicative of concentration of the disinfectant remaining above a minimum predetermined value, for at least a predetermined length of time.

[0036] The predetermined criteria may be calibrated based on one or more of: the system undergoing the disinfection process, applicable regulatory requirements, source of the fluid, end use of the fluid, target microorganism(s) of the disinfection, and/or type of disinfectant used in the disinfection process. The predetermined criteria may account for an effect of the magnitude of the detected values of the parameter indicative of concentration of the disinfectant on the time required for successful disinfection of the target microorganism(s), such that higher detected values of the parameter indicative of concentration of the disinfectant may cause the signal indicative of successful disinfection of the fluid system to be output sooner and lower detected values of the parameter indicative of concentration of the disinfectant may cause the signal indicative of successful disinfection of the fluid system to be output later. The predetermined criteria may account for an effect of the magnitude of the detected values of the parameter indicative of turbidity on the time required for successful disinfection of the target microorganism(s), such that higher detected values of the parameter indicative of turbidity may cause the signal indicative of successful disinfection of the fluid system to be output later and lower detected values of the parameter indicative of turbidity may cause the signal indicative of successful disinfection of the fluid system to be output sooner. Similarly, the predetermined criteria may account for the effect of temperature of the fluid and/or pH of the fluid on to the time required for successful disinfection of the target microorganism(s). Measurement of the temperature and/or pH of the fluid may be performed at the commencement of disinfection monitoring and/or intermittently during disinfection monitoring.

[0037] The detected values of the or each said parameter may be used to determine a cumulative disinfecting effect of the disinfection process, wherein the signal indicative of successful disinfection of the fluid system is output when the cumulative disinfecting effect determined is sufficient to successfully disinfect the target microorganism(s).

[0038] The method may further comprise determining a location of the apparatus.

[0039] The method may further comprise transmitting over a communications network, such as a mobile network, WiFi network, the Internet and/or local or wide area network, data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of the parameter indicative of concentration of the disinfectant; a location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system.

[0040] The method may further comprise storing data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of the parameter indicative of concentration of the disinfectant; a location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system.

[0041] The parameter indicative of turbidity may be any suitable measure of turbidity, including turbidity itself measured in NTU or equivalent.

[0042] The parameter indicative of concentration of the disinfectant may be any suitable measure indicative of concentration. For example, the parameter indicative of concentration of the disinfectant may be oxidation-reduction potential (ORP). The minimum predetermined value of ORP may vary depending on a number of factors, such as the system undergoing disinfection, the type of fluid carried by the system, and/or any applicable regulatory requirements.

Depending on such factors, the minimum predetermined value of ORP may be at least 500 mV, at least 600 mV, at least 700 mV or at least 750 mV.

[0043] Similarly, the maximum predetermined value of the parameter indicative of turbidity and/or the predetermined period of time may also vary depending on various factors, such as the system undergoing disinfection, the type of fluid carried by the system, and/or any applicable regulatory requirements. Depending on such factors, the maximum predetermined value of the parameter indicative of turbidity may be a value indicating a turbidity of less than around 5 NTU or less than around 3 NTU or less than around 2 NTU. Depending on the same factors, and/or others such as the detected values of the parameter indicative of concentration of the disinfectant, temperature of the fluid and/or pH of the fluid, the predetermined period of time may be at least 1 minute, at least 90 seconds or at least 2 minutes.

[0044] It will be appreciated that the method may be used to monitor disinfection of a fluid system associated with any one of a variety of fluids. For example, the apparatus may be used to monitor disinfection of a fluid system for raw water, recycled water, or waste water (e.g. tertiary effluent), or fluid systems associated with cooling towers or swimming pools or food and beverage production or distribution systems.

[0045] Any additional optional features of the apparatuses described in paragraphs [0011] to [0033] above may, where appropriate, also be optional features of the method described in paragraphs [0034] to [0044].

[0046] Also disclosed herein is a method of field monitoring disinfection of a fluid system undergoing a disinfection process, the method comprising: connecting an apparatus for field monitoring disinfection of a fluid system to a fluid system undergoing a disinfection process such that the apparatus receives a fluid flow from the fluid system; detecting a parameter indicative of concentration of a disinfectant in the fluid flow, the parameter being oxidation-reduction potential (ORP) of the fluid flow; and outputting a signal indicative of successful disinfection of the fluid system if the detected values of ORP satisfy a predetermined criteria for successful disinfection of a target microorganism.

[0047] The predetermined criteria may comprise the detected values of ORP remaining above a minimum predetermined value for at least a predetermined length of time.

[0048] The method may further comprise detecting a parameter indicative of turbidity of the fluid flow and the predetermined criteria may comprise both: the detected values of the parameter indicative of turbidity remaining below a maximum predetermined value; and the detected values of ORP remaining above a minimum predetermined value, for at least a predetermined length of time.

[0049] The predetermined criteria may be calibrated based on one or more of: the system undergoing the disinfection process, applicable regulatory requirements, source of the fluid, end use of the fluid, target microorganism(s) of the disinfection, and/or type of disinfectant used in the disinfection process. The predetermined criteria may account for an effect of the magnitude of the detected values of the parameter indicative of concentration of the disinfectant on the time required for successful disinfection of the target microorganism(s), such that higher detected values of the parameter indicative of concentration of the disinfectant may cause the signal indicative of successful disinfection of the fluid system to be output sooner and lower detected values of the parameter indicative of concentration of the disinfectant may cause the signal indicative of successful disinfection of the fluid system to be output later. The predetermined criteria may account for an effect of the magnitude of the detected values of the parameter indicative of turbidity on the time required for successful disinfection of the target microorganism(s), such that higher detected values of the parameter indicative of turbidity may cause the signal indicative of successful disinfection of the fluid system to be output later and lower detected values of the parameter indicative of turbidity may cause the signal indicative of successful disinfection of the fluid system to be output sooner. Similarly, the predetermined criteria may account for the effect of temperature of the fluid and/or pH of the fluid on to the time required for successful disinfection of the target microorganism(s). Measurement of the temperature and/or pH of the fluid may be performed at the commencement of disinfection monitoring and/or intermittently during disinfection monitoring.

[0050] The detected values of the or each said parameter may be used to determine a cumulative disinfecting effect of the disinfection process, wherein the signal indicative of successful disinfection of the fluid system is output when the cumulative disinfecting effect determined is sufficient to successfully disinfect the target microorganism(s).

[0051] The method may further comprise determining a location of the apparatus.

[0052] The method may further comprise transmitting over a communications network, such as a mobile network, WiFi network, the Internet and/or local or wide area network, data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of ORP; a location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system.

[0053] The method may further comprise storing data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of ORP; a location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system.

[0054] The parameter indicative of turbidity may be any suitable measure of turbidity, including turbidity itself measured in NTU or equivalent.

[0055] The minimum predetermined value of ORP may vary depending on a number of factors, such as the system undergoing disinfection, the type of fluid carried by the system, and/or any applicable regulatory requirements. Depending on such factors, the minimum predetermined value of ORP may be at least 500 mV, at least 600 mV, at least 700 mV, or at least 750 mV.

[0056] Similarly, the maximum predetermined value of the parameter indicative of turbidity and/or the predetermined period of time may also vary depending on various factors, such as the system undergoing disinfection, the type of fluid carried by the system, and/or any applicable regulatory requirements. Depending on such factors, the maximum predetermined value of the parameter indicative of turbidity may be a value indicating a turbidity of less than around 5 NTU or less than around 3 NTU or less than around 2 NTU. Depending on the same factors, and/or others such as the detected values of ORP, temperature of the fluid and/or pH of the fluid, the predetermined period of time may be at least 1 minute, at least 90 seconds or at least 2 minutes.

[0057] It will be appreciated that the method may be used to monitor disinfection of a fluid system associated with any one of a variety of fluids. For example, the apparatus may be used to monitor disinfection of a fluid system for raw water, recycled water, or waste water (e.g. tertiary effluent), or fluid systems associated with cooling towers or swimming pools or food and beverage production or distribution systems.

[0058] Any additional optional features of the apparatuses described in paragraphs [0011] to [0033] above may, where appropriate, also be optional features of the method described in paragraphs [0045] to [0057].

[0059] Also disclosed herein is a system for disinfecting a fluid system, comprising: an apparatus for field monitoring disinfection of a fluid system as defined in paragraph [0011] or [0022] above; and an apparatus for supplying disinfectant to a fluid in the fluid system, wherein the apparatus for field monitoring disinfection of a fluid system and the apparatus for supplying disinfectant to a fluid in the fluid system are communicatively linked.

[0060] The apparatus for field monitoring disinfection of a fluid system may be configured to transmit a signal indicative of a status of disinfection of the fluid system to the apparatus for supplying disinfectant to the fluid. In response to the received signal indicative of the status of disinfection, the apparatus for supplying disinfectant to the fluid may modify the flowrate of disinfectant to the fluid. For example, the apparatus for field monitoring disinfection of a fluid system may send a signal indicative of successful disinfection of the fluid system to the apparatus for supplying disinfectant to a fluid. On receiving the signal indicative of successful disinfection, the apparatus for supplying disinfectant to a fluid may reduce or stop a flow of disinfectant to the fluid and/or may switch off or into a standby mode. After sending the signal indicative of successful disinfection, the apparatus for field monitoring disinfection of a fluid system may switch off or into a standby mode. The apparatus for field monitoring disinfection of a fluid system may send a signal indicative of commencement of disinfection monitoring to the apparatus for supplying disinfectant to a fluid. On receiving the signal indicative of commencement of disinfection monitoring, the apparatus for supplying disinfectant to a fluid may switch from a standby mode into an active mode and/or start a flow of disinfectant to the fluid in the fluid system. The apparatus for supplying disinfectant to a fluid may send to the apparatus for field monitoring disinfection of a fluid system a signal indicative of commencement of disinfectant supply. Receipt of the signal indicative of commencement of disinfectant supply may trigger the apparatus for field monitoring disinfection of a fluid system to switch from a standby mode into an active mode and/or to start monitoring disinfection of the fluid system. The apparatus for field monitoring disinfection of a fluid system may start monitoring disinfection of the fluid system immediately after receiving the signal indicative of commencement of disinfectant supply, or after a predetermined delay.

[0061] Any additional optional features of the apparatuses described in paragraphs [0011] to [0033] above may, where appropriate, also be optional features of the system described in paragraphs [0059] and [0060].

Brief Description of Drawings [0062] Embodiments of the presently disclosed subject matter will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a perspective view of an embodiment of an apparatus for field monitoring disinfection of a fluid system;

Figure 2 is a front view of an embodiment of an apparatus for field monitoring disinfection of a fluid system, shown mounted on a wheeled trolley;

Figure 3 is a side view of the apparatus of Figure 2;

Figure 4 is a schematic diagram of components of the apparatus of Figure 1; and Figure 5 is graph showing an example of a measured change in ORP and turbidity of a fluid system undergoing disinfection as a function of time.

Description of Embodiments [0063] Figure 1 shows an embodiment of an apparatus 100 for field monitoring disinfection of a fluid system, such as a potable water distribution system comprising a pipeline and any associated components, such as one or more tanks or reservoirs, one or more filters, one or more valves, one or more manifolds or distribution blocks or pumps, and/or any other component the system that requires disinfection. The apparatus 100, or alternative embodiments thereof, may also be used to monitor disinfection of other fluid systems for raw water, recycled water, or waste water (e.g. tertiary effluent), or fluid systems associated with cooling towers or swimming pools or food and beverage production or distribution systems.

[0064] The apparatus 100 comprises a housing 101 having an inlet 102 for connection to a water asset or other fluid system undergoing disinfection using an oxidising disinfectant, such as chlorine, chlorine dioxide, chloramine, hydrogen peroxide or ozone. The housing 101 is an ingress protection (IP) rated plastic enclosure. In the embodiment shown in Figures 2 and 3, the housing 101 is configured to be attached to a trolley 120 for ease of transport between on-site sampling points. The embodiment shown in Figures 2 and 3 further comprises a pair of handles 103 mounted to the housing 101 for lifting and positioning the apparatus 100.

[0065] The apparatus 100 also comprises an on/off switch 104 and a user interface 105 for receiving user input. The user interface 105 may also be adapted to display data to a user. A signalling device 106 in the form of three LED lights (red 106a, amber 106b and green 106c) is also mounted on the apparatus for outputting a signal indicative of the following disinfection statuses of the fluid system: status A (corresponding with illumination of red LED 106a) in which disinfection is not occurring; status B (corresponding with illumination of amber LED 106b) in which disinfection is occurring but not complete; and status C (corresponding with illumination of green LED 106c) in which disinfection is complete. These disinfection statuses are described in more detail below.

[0066] The inlet 102 is adapted for engagement to an inflow hose which can be connected to the fluid system, for example via a standpipe in fluid communication with a pipeline undergoing disinfection. Outlets 107 are further provided through which the fluid flow can exit the apparatus 100.

[0067] Figure 4 shows a schematic diagram of components of apparatus 100, which comprise an instrument 108 for detecting a parameter indicative of turbidity T of the fluid flow received from the inlet 102 and an instrument 109 for detecting a parameter indicative of concentration of a disinfectant D in the fluid flow received from the inlet 102. In the embodiment shown in Figure 4, the instruments 108 and 109 are mounted in parallel, such that fluid flow received from the inlet 102 is split into two fluid pathways 110 and 111, with each fluid pathway 110 and 111 connected to a respective instrument 108 and 109. In an alternate embodiment, the instruments 108 and 109 may be located in series such that the fluid flow received from the inlet 102 flows through the respective instruments 108 and 109 consecutively. In the illustrated embodiments, instrument 108 is a turbidity meter, which measures turbidity directly in Nephelometric Turbidity Units (NTU), and instrument 109 is a flow cell for measuring oxidation-reduction potential (ORP), wherein ORP is a measure indicative of disinfectant concentration D.

[0068] A controller 112 is associated with instruments 108 and 109. The controller 112 is further associated with the signalling device 106 and is configured to output a signal, via the signalling device 106, indicative successful disinfection of the fluid system if detected values of turbidity and of ORP satisfy a predetermined criteria. The predetermined criteria may be calibrated based on one or more of: the system and/or fluid undergoing disinfection, and/or any applicable regulatory requirements and/or one or more parameters selected from: source of the fluid, end use of the fluid, target microorganism(s) of the disinfection, disinfectant being used, concentration of the disinfectant in the fluid, temperature of the fluid and/or pH of the fluid. In the illustrated embodiment, the predetermined criteria comprises both: (1) instrument 108 indicating that turbidity T remains below a maximum predetermined value Tmax, and (2) instrument 109 indicating that ORP (i.e. the parameter indicative of disinfectant concentration D) remains above a minimum predetermined value Dmjn, for at least a predetermined period of time tmin· [0069] The controller 112 may further be associated with the user interface 105 such that the user may input data, for example to set Tmax, Dmjn, and/or tmjn.

[0070] Values for Tmax, Dmin and/or tmin may be determined by the user and directly input via the user interface 105, or may be set by controller 112 in response to user input data or other data input(s), such as data relating to the source of the fluid, end use of the fluid, target microorganism(s) of the disinfection, disinfectant being used, concentration of the disinfectant in the fluid, temperature of the fluid and/or pH of the fluid.

[0071] The source of the fluid for disinfection may indicate different properties, such as the types and quantities of microorganisms most likely to be present in the fluid. As such, the source of the fluid may act as a proxy for the target microorganism(s) of the disinfection. Moreover, different microorganisms require different concentrations of disinfectant and different contact times with the disinfectant to achieve disinfection. Accordingly, identification of the target microorganisms and/or of the source of the fluid may influence the selection of values of Tmax, Dmin and/or tmin.

[0072] The end use of the fluid after disinfection may also influence the selection of Tmax, Dmjn and/or tmjn values. For example, fluid intended for use as potable water would generally require more conservative values for Tmax, Dmin and/or tmin, whereas less conservative values may be appropriate for fluid intended for environmental discharge. Moreover, a fluid intended for use as potable water may require turbidity T at the completion of disinfection to be lower than the turbidity T that may be appropriate for fluid intended for environmental discharge. However, fluid intended for environmental discharge may require a relatively high Dmin to reduce its impact on existing ecosystems in the environment to which the treated fluid is discharged.

[0073] Disinfectants for fluids may include any oxidant such as chlorine, chlorine dioxide, chloramine, hydrogen peroxide and ozone. As the efficacy of different disinfectants can vary, both generally and with respect to particular target microorganisms, the disinfectant used for the disinfection may also influence the selection of Tmax, Dmjn and/or tmjn values.

[0074] The efficacy of a disinfectant may be reduced with decrease in temperature and/or increase in pH. Accordingly, the temperature and pH of the fluid undergoing disinfection may also influence the selection of Tmax, Dmjn and/or tmjn values.

[0075] In one example, the user may input data indicating the source and intended use of the fluid undergoing disinfection and the type of disinfectant being used via the user interface 105, and the controller 112 may be responsive to instruments that provide data indicating the temperature and pH of the fluid undergoing disinfection. From these inputs, the controller 112 sets the appropriate Tmax, Dmin and/or tmin values. The user or a controller 112 may interrogate a a look up table such as is shown in Table 1 below to facilitate setting the Tmax, Dmin and/or tmjn values. As system parameters, such as the pH and temperature of the fluid undergoing disinfection may vary during the disinfection process, the controller may adjust the Tmax, Dmjn and/or tmjn values continuously or intermittently.

[0076] Table 1 depicts Ct values, i.e. the product of the concentration of the disinfectant and the contact time with the fluid being treated, for a 3-log inactivation (i.e. reduction by a factor of a 10 ) of the microorganism Giardia cysts with free chlorine as the disinfectant. As can be seen, Ct values for this system vary with temperature, pH and disinfectant concentration. The contact times in Table 1 can be adjusted for turbidity to account for the effect of turbidity on the contact time required to achieve 3-log inactivation of the microorganism.

Table 1: Ct values (min-mg/L) for a 3-log inactivation of Giardia cysts by free chlorine

Note: Table sourced from Appendix B, EPA Guidance Manual “LT1ESWTR Disinfection Profiling and Benchmarking”, U.S. Environmental Protection Agency (2003) [0077] Rather than using a look up table, Tmax, Dmin and/or tmjn values may be based on a mathematical model, for example a mathematical model comprising an algorithm representative of the data in Table 1 and/or similar tables for other microorganisms and/or other disinfectants and/or different levels of microorganism inactivation, relating the input data to the appropriate Tmax, Dmin and/or tmin values. The mathematical model can also be configured to account for the effect of turbidity on the contact time required to achieve the desired level of inactivation of the microorganism.

[0078] The apparatus 100 may include a global positioning system (GPS) device or similar instrument for determining the location of the apparatus 100 and thereby the sampling location. This allows for geotagging of the data collected by the apparatus 100.

[0079] The apparatus 100 comprises an electronic memory, such as a data logger 113, for storing data related to: the detected values of turbidity T and ORP; and the sampling location as determined by the onboard GPS device. The data logger 113 may also store data indicative of the disinfection status A, B or C, as well as date/time data. The apparatus 100 also comprises a transmitter 114 for transmitting all or a selection of this data over a communications network.

For example, in some cases, the transmitter may only transmit data indicative of disinfection status C (i.e. disinfection complete) and the sampling location. This transmission of data allows for remote monitoring of the disinfection process by relevant parties and for external data logging of the disinfection process. In some embodiments, the transmitter 114 may also act as a receiver for the onboard GPS device.

[0080] The apparatus 100 may be battery operated and/or connectable to mains power through a plug attachment. In the embodiment of Figure 4, the apparatus 100 is powered by a battery 115. The apparatus 100 comprises one or more solar panels 116 for supplying electrical energy to the battery 115 via a charge controller 117.

[0081] In use, the apparatus 100 is connected via the inlet 102 to the fluid system undergoing disinfection. The inflowing fluid passes through the instruments 108 and 109 for monitoring of the fluid’s turbidity T and ORP as a function of time t. The monitoring of T and ORP may be continuous or intermittent. An outlet hose may be connected to the outlets 107 to direct outflowing fluid away from the area of operation.

[0082] As shown in Figure 5, status A (disinfection not occurring) applies when the apparatus 100 is turned on but whilst the detected turbidity T is above Tmax and/or the detected ORP is below Dmin. Status B (disinfection occurring but not yet complete) applies when, for less than tmjn, both the detected turbidity T is below Tmax and the detected ORP is above Dmjn. Status C (disinfection complete) applies when, for at least tmin, both the detected turbidity T has been below Tmax and the detected ORP has been above Dmin.

[0083] As discussed previously, the values for parameters Tmax, Dmjn and tmjn may be selected based on various factors, such as the system to be disinfected and the applicable regulatory requirements for disinfection. For example, in the scenario applicable to Figure 5, Tmax is set at 2 NTU, Dmin at 750 mV and tmjn at 2 minutes.

[0084] The apparatus 100 may be communicatively linked, for example via the GSM network or another communications network, with a disinfectant dosing apparatus that is supplying disinfectant to fluid in the fluid system to facilitate a degree of automation of the disinfection and disinfection monitoring processes. The apparatus 100 may transmit a signal indicative of the status of disinfection of the fluid system to the disinfectant dosing apparatus. In response to the received signal, the disinfectant dosing apparatus may modify the flowrate of disinfectant to the fluid. For example, the apparatus 100 may send a signal indicative of successful disinfection of the fluid system to the disinfectant dosing apparatus and, on receiving the signal, the disinfectant dosing apparatus may reduce or stop a flow of disinfectant to the fluid and/or may switch off or into a standby mode. After sending the signal indicative of successful disinfection, the apparatus 100 may switch off or into a standby mode. Similarly, the apparatus 100 may send a signal indicative of commencement of disinfection monitoring to the disinfectant dosing apparatus and, on receiving this signal, the disinfectant dosing apparatus may start a flow of disinfectant to the fluid or switch from a standby mode into an active mode. Alternatively, the disinfectant dosing apparatus may send to apparatus 100 a signal indicative of commencement of disinfectant supply and receipt of the signal may trigger apparatus 100 to start monitoring disinfection of the fluid system. In such an embodiment, apparatus 100 may start monitoring disinfection immediately after receiving the signal indicative of commencement of disinfectant supply, or after a predetermined delay.

[0085] It will be appreciated by persons skilled in the art that numerous variations and/or modifications may be made to the above-described embodiments, without departing from the broad general scope of the present disclosure. The present embodiments are, therefore, to be considered in all respects as illustrative and not restrictive.

Claims

CLAIMS:

1. An apparatus for field monitoring disinfection of a fluid system undergoing a disinfection process, the apparatus comprising: an inlet for connection to a fluid system undergoing a disinfection process; an instrument for detecting a parameter indicative of turbidity of a fluid flow received from the inlet; an instrument for detecting a parameter indicative of concentration of a disinfectant in the fluid flow received from the inlet; and a controller associated with the instrument for detecting a parameter indicative of turbidity and the instrument for detecting a parameter indicative of concentration of the disinfectant, the controller being configured to output a signal indicative of successful disinfection of the fluid system if detected values of the parameter indicative of turbidity and of the parameter indicative of concentration of the disinfectant satisfy a predetermined criteria for successful disinfection of a target microorganism.
2. An apparatus according to claim 1, wherein the predetermined criteria comprises both: the detected values of the parameter indicative of turbidity remaining below a maximum predetermined value; and the detected values of the parameter indicative of concentration of the disinfectant remaining above a minimum predetermined value, for at least a predetermined period of time.
3. An apparatus according to claim 2, wherein the parameter indicative of concentration of the disinfectant is oxidation-reduction potential (ORP).
4. An apparatus according to claim 3, wherein the minimum predetermined value of ORP is at least 500 mV, at least 600 mV, at least 700 mV or at least 750 mV.
5. An apparatus according to any one of claims 2 to 4, wherein the maximum predetermined value of the parameter indicative of turbidity is a value that indicates a turbidity of less than about 5 NTU or less than about 3 NTU or less than about 2 NTU.
6. An apparatus according to any one of claims 2 to 5, wherein the predetermined period of time is at least 1 minute, at least 90 seconds or at least 2 minutes.
7. An apparatus according to any one of the preceding claims, further comprising a transmitter for transmitting over a communications network data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of the parameter indicative of concentration the disinfectant; a location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system.
8. An apparatus according to any one of the preceding claims, further comprising a data storage device for storing data relating to one or more of: detected values of the parameter indicative of turbidity; detected values of the parameter indicative of concentration of the disinfectant; a location of the apparatus; and/or the signal indicative of successful disinfection of the fluid system.
9. A method of field monitoring disinfection of a fluid system undergoing a disinfection process, the method comprising: connecting an apparatus for field monitoring disinfection of a fluid system to a fluid system undergoing a disinfection process such that the apparatus receives a fluid flow from the fluid system; detecting a parameter indicative of turbidity of the fluid flow; detecting a parameter indicative of concentration of a disinfectant in the fluid flow; and outputting a signal indicative of successful disinfection of the fluid system if detected values of the parameter indicative of turbidity and of the parameter indicative of concentration of the disinfectant satisfy a predetermined criteria for successful disinfection of a target microorganism.
10. A method according to claim 9, wherein the predetermined criteria comprises both: the detected values of the parameter indicative of turbidity remaining below a maximum predetermined value, and the detected values of the parameter indicative of concentration of the disinfectant remaining above a minimum predetermined value, for at least a predetermined length of time.
11. A method according to claim 10, wherein the parameter indicative of concentration of the disinfectant is oxidation-reduction potential (ORP).
12. A method according to claim 11, wherein the minimum predetermined value of ORP is at least 500 mV, at least 600 mV, at least 700 mV or at least 750 mV.
13. A method according to any one of claims 9 to 12, wherein the maximum predetermined value of the parameter indicative of turbidity is a value that indicates a turbidity of less than about 5 NTU or less than about 3 NTU or less than about 2 NTU.
14. An apparatus according to any one of claims 1 to 8 or a method according to any one of claims 9 to 13, wherein: the predetermined criteria is calibrated based on one or more inputs relating to: the system undergoing the disinfection process, fluid type, applicable regulatory requirements, source of the fluid, end use of the fluid, target microorganism(s) of the disinfection, and/or type of disinfectant used in the disinfection process.
15. An apparatus or method according to any one of the preceding claims, wherein the predetermined criteria accounts for the effect of temperature of the fluid and/or pH of the fluid on the time required for successful disinfection of the target microorganism(s).
16. An apparatus according to any one of claims 1 to 8, 14 or 15 or a method according to any one of claims 9 to 13, 14 or 15 that uses the detected values of the parameter indicative of turbidity and the detected values of the parameter indicative of concentration of the disinfectant to determine a cumulative disinfecting effect of the disinfection process, wherein the signal indicative of successful disinfection of the fluid system is output when the cumulative disinfecting effect determined is sufficient to successfully disinfect the target microorganism(s).
17. A system for disinfecting a fluid system comprising: an apparatus for field monitoring disinfection of a fluid system, the apparatus being as defined in any one of claims 1 to 8 or 14 to 16; and an apparatus for supplying disinfectant to a fluid in the fluid system, wherein the apparatus for field monitoring disinfection of a fluid system and the apparatus for supplying disinfectant to a fluid in the fluid system are communicatively linked.
18. A system according to claim 17, wherein the apparatus for field monitoring disinfection of a fluid system is configured to transmit a signal indicative of a status of disinfection of the fluid system to the apparatus for supplying disinfectant to the fluid and, in response to the received signal indicative of the status of disinfection, the apparatus for supplying disinfectant to the fluid is configured to modify the flowrate of disinfectant to the fluid.
19. A system according to claim 17 or claim 18, wherein the apparatus for field monitoring disinfection of a fluid system is configured to send a signal indicative of commencement of disinfection monitoring to the apparatus for supplying disinfectant to a fluid and, in response to receiving the signal indicative of commencement of disinfection monitoring, the apparatus for supplying disinfectant to a fluid is configured to start a flow of disinfectant to the fluid in the fluid system.
20. A system according to any one of claims 17 to 19, wherein the apparatus for supplying disinfectant to a fluid is configured to send to the apparatus for field monitoring disinfection of a fluid system a signal indicative of commencement of disinfectant supply and, in response to receipt of the signal indicative of commencement of disinfectant supply, the apparatus for field monitoring disinfection of a fluid system is configured to start monitoring disinfection of the fluid system.