Water contaminant measurement system and methods for measuring concentration levels of contaminants in water

A contaminant measurement system is provided. The system is operable to detect and measure a concentration level of a preselected contaminant, e.g., lead, in water disposed within a chamber of the system. The system includes a detection agent that is operable to interact with the preselected contaminant in the water. The detection agent can be a plurality of polymeric beads or a membrane, for example. The system has a sensing circuit that includes a pair of electrodes spaced from one another and both at least partially disposed in the water. A controller is communicatively coupled with the sensing circuit and is configured to receive one or more electric signals from the sensing circuit. The controller determines a parameter indicative of the concentration level of the preselected contaminant based on the one or more electrical signals. The controller then determines and outputs the concentration level of the preselected contaminant.

FIELD OF THE INVENTION

The present subject matter relates generally to water quality analysis systems and methods for detecting contaminants in water, such as e.g., lead.

BACKGROUND OF THE INVENTION

Water is an essential element for life and has many uses. Generally, it is desirable to remove contaminants from water designated for safe drinking and use. This may be done via known treatment and filtration processes. In some instances, however, water designated for use may not be properly treated or may contain certain contaminants, such as e.g., lead, cadmium, chromium, and other toxic heavy metals, etc. Such contaminants may be harmful to human health and thus it is desirable to detect such contaminated water and ensure that it is not used. Conventional systems and processes for detecting and measuring concentration levels of contaminants in water have been unsatisfactory. For instance, conventional systems for measuring concentration levels of contaminants in water are relatively expensive and the process for detecting and measuring concentration levels typically has a long turnaround time and must be conducted at an offsite laboratory.

Accordingly, a water contaminant measurement system and methods for detecting and measuring concentration levels of preselected contaminants in water that address one or more of the challenges noted above would be useful.

BRIEF DESCRIPTION OF THE INVENTION

In one exemplary aspect, a contaminant measurement system for measuring a concentration level of a preselected contaminant in a volume of water is provided. The contaminant measurement system includes a housing defining a chamber configured for receipt of the volume of water. Further, the contaminant measurement system includes a detection agent disposed in the volume of water in the chamber, the detection agent configured to selectively interact with the preselected contaminant in the volume of water in the chamber. Further, the contaminant measurement system includes a sensing circuit having a first electrode and a second electrode both disposed at least partially in the volume of water in the chamber, the first electrode spaced at a distance from the second electrode. Moreover, the contaminant measurement system includes a controller in electrical communication with the sensing circuit. The controller is configured to: receive one or more electric signals from the sensing circuit; determine a parameter value indicative of the concentration level of the preselected contaminant in the volume of water based at least in part on the one or more electric signals; determine the concentration level of the preselected contaminant in the volume of water in the chamber based at least in part on the parameter value; and output the concentration level of the preselected contaminant in the volume of water in the chamber.

In another exemplary aspect, a method for measuring a concentration level of a preselected contaminant in a volume of water disposed within a chamber of a contaminant measurement system is provided. The method includes selectively interacting a detecting agent immersed in the volume of water with the preselected contaminant in the volume of water for a first time period. Further, the method includes receiving, from a sensing circuit comprised of a first electrode and a second electrode both at least partially disposed in the volume of water, one or more electric signals. In addition, the method includes determining a parameter value indicative of the concentration level of the preselected contaminant in the volume of water based at least in part on the one or more signals. In addition, the method includes determining the concentration level of the preselected contaminant in the volume of water within the chamber based at least in part on the determined parameter value. Furthermore, the method includes outputting the determined concentration level of the preselected contaminant in the volume of water within the chamber.

DETAILED DESCRIPTION

As used herein, terms of approximation, such as “approximately,” “substantially,” or “about,” refer to being within a ten percent (10%) margin of error of the stated value. Moreover, as used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows.

FIG. 1provides a schematic view of an exemplary water contaminant measurement system100according to an exemplary embodiment of the present subject matter. Generally, water contaminant measurement system100is operatively configured to detect and measure a concentration or concentration level of a preselected contaminant (e.g., lead) in water. The concentration level of output by system100may be presented to a user, e.g., so that corrective or preventative action may be taken in the event the concentration level of the preselected contaminant is above a safe drinking or use threshold (e.g., 10 micrograms per liter). Water contaminant measurement system100can be located in a number of suitable locations, such as e.g., within a refrigerator appliance as a point of use application, connected to a water supply line of a household or building as a point of entry application, in a water treatment plant, in fluid communication with a well, or in other suitable locations and for other suitable applications. In some embodiments, water contaminant measurement system100may be a dynamic system that is operable to detect and measure the concentration level of a preselected contaminant, e.g., lead, in a continuous flow of water. In yet other embodiments, water contaminant measurement system100may be a static system that is operable to detect and measure the concentration level of a preselected contaminant in a static volume of water.

As shown inFIG. 1, water contaminant measurement system100includes a cylinder or housing110defining a chamber112configured for receipt of a volume of water W. Housing110extends between a top end and a bottom end along an axial direction A. Housing has an inlet port120defining an inlet121of chamber112and an outlet port122defining an outlet123of chamber112. Inlet port120is positioned at or adjacent the top end of housing110and outlet port122is positioned at or adjacent the bottom end of housing110. Inlet port120and outlet port122may be positioned in other suitable locations as well such that the water can drain off easily.

For this embodiment, chamber112is in fluid communication with a water source114, such as e.g., a water line of a home or water treatment plant. Particularly, an inlet supply conduit116provides fluid communication between water source114and inlet121of chamber112. An inlet valve118is positioned along inlet supply conduit116and is operable to selectively allow a volume of water to flow into chamber112through inlet121of chamber112. Inlet valve118is movable between an open position in which fluid may flow through inlet valve118and a closed position in which fluid is prevented from flowing through inlet valve118. Water W may drain from chamber112through outlet123via an outlet supply conduit124in fluid communication with outlet123. Outlet supply conduit124is operable to allow water to drain from chamber112. An outlet valve126is positioned along outlet supply conduit124to selectively allow the volume of water W within chamber112to drain therefrom. Outlet valve126is movable between an open position in which fluid may flow through outlet valve126and a closed position in which fluid is prevented from flowing through outlet valve126. Inlet valve118and outlet valve126may both be normally closed solenoid valves, for example, and may both be communicatively coupled with a controller of water contaminant measurement system100so that they may be controlled to move between their respective open and closed positions.

In some alternative embodiments, chamber112may not include inlet and outlet ports, inlet and outlet conduits, or inlet and outlet valves. Rather, in such embodiments, chamber112has an opening128at a top end of housing110that provides selective access to chamber112, e.g., for pouring into or removing water from chamber112. Accordingly, in such embodiments, water contaminant measurement system100can be a static or standalone system, which can be used to access the water quality directly at an affected site, e.g., river, ponds, lakes. Thus, notably, in some embodiments, water measurement system100is mobile or capable of easily being transported from one location to another.

Water contaminant measurement system100includes a detection agent130disposed in the volume of water W within chamber112. Detection agent130is operatively configured to selectively interact with a preselected contaminant in the water W within chamber112. Without wishing to be bound by any particular theory, the interaction between ions of the preselected contaminant and detection agent130may be ionic bonding, electrostatic attraction (e.g., hydrogen bonding), van der Waals forces, etc., which changes the conductivity/resistivity of the water mixture. Detection agent130may be any suitable type of medium or membrane capable of selectively interacting with a designated or preselected contaminant in the water W. By way of example, the contaminant or pollutant may be lead, another heavy metal, some non-metal contaminant, chlorine, chloroform, cadmium, chromium, phenols, pharmaceuticals, microbes, cysts, arsenic, and/or other undesirable substances or compounds.

The chemistry of detection agent130is preferably selected such that detection agent130selectively interacts with a contaminant that is desired to be measured. For instance, for this embodiment, detection agent130is a plurality of polymeric beads132. More specifically, the plurality of beads132are sodium hydroxide treated polyacrylonitrile homopolymer beads. The plurality of beads132depicted inFIG. 1have been surface treated and formed with materials such that they are configured to interact with lead ions within the volume of water W in chamber112. For example, the nitrile groups of the polyacrylonitrile homopolymer beads132may interact with the lead ions (e.g., via ionic bonding, electrostatic attraction (e.g., hydrogen bonding), van der Waals forces, etc.), e.g., to change the conductivity/resistivity of the water mixture or the voltage across or current flowing between opposing electrodes. In some embodiments, the synthesized beads132may be prepared by dissolution of a polymer (e.g., polyacrylonitrile homopolymer) in a solvent (dimethyl-form-amide) and extrusion through a needle assembly followed by transformation of the liquid solution to a gel capsular structure. Afterwards, the beads132may be treated with sodium hydroxide, having a strength varying from 0.1(N) to 1(N) for about twenty-four (24) hours. Although the beads132are shown as having spherical shapes, these interacting agents132may have other suitable shapes.

As further depicted inFIG. 1, the plurality of beads132or detection agent130may be housed or contained within a basket chamber136defined by a basket134. Basket134has a plurality of perforations (not shown) that provide fluid communication between chamber112and basket chamber136of basket134. Basket134is removably insertable into chamber112of housing110. When basket134is inserted into chamber112, a top cap138engages a rim of the housing and is seated thereon. Top cap138has a greater diameter than the diameter of opening128so that a user may easily grasp top cap138and remove basket134from chamber112. As depicted inFIG. 1, top cap138is configured to hold and secure a pair of opposing electrodes of the system in place. Accordingly, the entire electrochemical cell and basket may easily be inserted into or removed from chamber112of housing110.

Water contaminant measurement system100includes a sensing circuit140for detecting and measuring a contaminant concentration level of a preselected containment in the volume of water W in chamber112. The sensing circuit140includes a first electrode141disposed at least partially in the volume of water W in chamber112. Sensing circuit140also includes a second electrode142spaced from first electrode141, e.g., by a distance D. Like first electrode141, second electrode142is disposed at least partially in the volume of water W in chamber112of housing110. First electrode141may be a cathode and second electrode142may be an anode, or vice versa. First electrode141and second electrode142may be spaced from one another by any suitable distance. As one example, the distance D between first electrode141and second electrode142may be about one millimeter (1 mm). Top cap138may retain and keep proper spacing between first electrode141and second electrode142.

First electrode141and second electrode142are formed of dissimilar conducting materials. For this embodiment, first electrode141is formed of a first electrically conducting material and second electrode142is formed of a second electrically conducting material that is dissimilar to the first electrically conducting material of first electrode141. As one example, the first electrically conducting material of first electrode141may be copper and the second electrically conducting material of second electrode142may be graphite. However, the electrodes141,142may be formed of other materials as well, such as e.g., platinum, gold, or other carbon materials. Preferably, at least one of first electrode141and second electrode142is inert and the other electrode is reactive. In some embodiments, first electrode141or second electrode142is coated with a suitable material.

A controller150is in electrical communication with sensing circuit140, e.g., via one or more wired or wireless communication links. Generally, operation of water contaminant measurement system100is controlled by controller150. Further, controller150is configured to output a concentration level of a preselected contaminant in the volume of water W in chamber112as will be described in detail herein. Controller150may be communicatively coupled with a control panel (not shown) so that a user may control and set features of system100. The control panel may be a control panel dedicated to system100or may be a multiuse control panel, such as e.g., a control panel for a refrigerator appliance. In response to user manipulation of one or more user controls of the control panel, controller150performs one or more operations. As described in more detail below with respect toFIG. 2, controller150may include a memory and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with methods described herein. Alternatively, controller150may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software.

The control panel and other components of system100may be in communication with controller150via one or more signal lines or shared communication busses. For instance, as shown inFIG. 1, controller150is communicatively coupled with inlet valve118and outlet valve126. Further, controller150is communicatively coupled with a display device160. As will be described below, in some embodiments, the contaminant concentration level is output by controller150to display device160so that the determined contaminant concentration level is presented to a user. For instance, as shown inFIG. 1, display device160may present a particular concentration level (e.g., “170 ppm”) to a user as parts per million (ppm) or in some other suitable units. Display device160may be any suitable display. For instance, display device160may be an LCD, LED, or OLED display. In some embodiments, display device160and controller150are both positioned onboard the same control board. In other embodiments, display device160may be a display of an appliance (e.g., a refrigerator appliance) or other device to which water contaminant measurement system100is connected.

FIG. 2provides a schematic view of controller150of water contaminant measurement system100ofFIG. 1according to example embodiments of the present disclosure. Controller150may be used to implement water contaminant measurement system100and methods described herein. Although shown as a single device, it will be appreciated that water contaminant measurement system100can include one or more controllers. As shown, controller150can include one or more processor(s)151and one or more memory device(s)152. The one or more processor(s)151can include any suitable processing device, such as a microprocessor, microcontroller, integrated circuit, an application specific integrated circuit (ASIC), a digital signal processor (DSP), a field-programmable gate array (FPGA), logic device, one or more central processing units (CPUs), graphics processing units (GPUs) (e.g., dedicated to efficiently rendering images), processing units performing other specialized calculations, etc. The memory device(s)152can include one or more non-transitory computer-readable storage medium(s), such as RAM, ROM, EEPROM, EPROM, flash memory devices, magnetic disks, etc., and/or combinations thereof.

The memory device(s)152can include one or more computer-readable media and can store information accessible by the one or more processor(s)151, including instructions153that can be executed by the one or more processor(s)151. For instance, the memory device(s)152can store instructions153for running one or more software applications, displaying a user interface, receiving user input, processing user input, etc. In some implementations, the instructions153can be executed by the one or more processor(s)151to cause the one or more processor(s)151to perform operations, e.g., such as one or more portions of methods described herein. The instructions153can be software written in any suitable programming language or can be implemented in hardware. Additionally, and/or alternatively, the instructions153can be executed in logically and/or virtually separate threads on processor(s)151.

The one or more memory device(s)152can also store data154that can be retrieved, manipulated, created, or stored by the one or more processor(s)151. The data154can include, for instance, data to facilitate performance of methods described herein. The data154can be stored in one or more database(s). The one or more database(s) can be connected to controller150by a high bandwidth LAN or WAN, or can also be connected to controller150through network(s) (not shown). The one or more database(s) can be split up so that they are located in multiple locales. In some implementations, the data154can be received from another device.

Controller150can also include a communication module or interface155used to communicate with one or more other component(s) of controller150over the network(s). The communication interface155can include any suitable components for interfacing with one or more network(s), including for example, transmitters, receivers, ports, controllers, antennas, or other suitable components. Further, controller150can include a machine-learned model156that is operable to adjust a parameter trend line as will be described herein.

With reference again toFIG. 1, in some exemplary embodiments, water contaminant measurement system100can optionally include a power supply170positioned along sensing circuit140. Power supply170may be any suitable device capable of flowing an electric current through sensing circuit140. By way of example, power supply170may be, e.g., a battery, a DC power supply, an AC power supply, an AC actuator, etc. In some embodiments, power supply170is operable to apply a voltage to the electrodes141,142, e.g., to better maintain the polarities of the electrodes141,142.

In yet other embodiments, water contaminant measurement system100can optionally include a measurement device180. Measurement device180is positioned along and in electrical communication with sensing circuit140. For this embodiment, measurement device180is positioned on the same control board as controller150; however, in other embodiments, measurement device180may be positioned offboard the control board of controller150. Measurement device180is operable to determine a parameter value based on one or more electric signals received from electrodes141,142. By way of example, measurement device180may be a multimeter, a voltmeter, an ampimeter, an electrical conductivity meter (EC), or some other device operable for converting or determining a parameter based on one or more electrical signals received. Example parameters include a voltage between first electrode141and second electrode142, an electrolytic current flowing between first electrode141and second electrode142(and thus through sensing circuit140), a conductivity of the volume of the water W within chamber112, and a resistivity of the volume of water W within chamber112. As noted above, water contaminant measurement system100can optionally include measurement device180. In some alternative exemplary embodiments, controller150may include an analog reading chip, a software program or application, or a combination thereof that is operable to interpret incoming electrical signals and determine or convert the electrical signals into a parameter value, e.g., a voltage, a current, an electrical conductance, or a resistivity.

In some other embodiments, water contaminant measurement system100can optionally include an amplification circuit190positioned along and in electrical communication with sensing circuit140. Amplification circuit190is operable to amplify electric signals received from electrodes141,142. The amplified signals may then be routed to a filter, measurement device180, or to processor(s)151of controller150for processing. Amplification circuit190can include electrical components for amplifying an electrical signal, such as e.g., diodes, capacitors, resistors, etc.

In some embodiments, a filter device is optionally positioned upstream and/or downstream of chamber112of water contaminant measurement system100. For this embodiment, a filter device125is positioned along inlet supply conduit116upstream of chamber112. Filter device125is operable to remove certain contaminants from the water flowing from water source114through water contaminant measurement system100and to a downstream destination. Particularly, filter device125can be operable to filter suspended solids, total dissolved solids, and/or large size particulates (e.g., sand particles) from the water stream. Advantageously, removal of such solids and large size particulates may provide for more accurate concentration level measurements and may prevent the detecting agent130or beads132from being damaged. In some embodiments, chamber112of housing110may be integrated into filtration device125such that filter device125and water contaminant measurement system100are configured as a single unit.

General operation of water contaminant measurement system100will now be described. After calibrating water contaminant measurement system100, and more particularly controller150(e.g., in a manner described in detail below), water contaminant measurement system100is operatively configured to detect and measure a concentration level of a preselected contaminant in a volume of water W. The volume of water W is provided to chamber112of housing110. When the volume of water W enters chamber112, detecting agent130becomes immersed in the water W. In this embodiment, detecting agent130is polymeric beads132that are configured to interact with ions of the preselected contaminant (e.g., lead). When the lead ions interact with the polymeric beads132, the conductivity/resistivity of the water mixture changes. Sensing circuit140, via electrodes141,142, senses this change and one or more signals are received by measurement device180and/or controller150. The sensed signals are converted into a parameter value, such as e.g., a voltage, a current, an electrical conductance, or a resistivity. That is, controller150or measurement device180determines a parameter value based on the one or more signals. Controller150receives the determined parameter value (e.g., a voltage) and determines the concentration level of the preselected contaminant based on the determined parameter value. The parameter value used to determine the concentration level may be a predicted value or may be a measured value. The determined concentration level may then be output. For instance, the concentration level may be output to display device160such that the concentration level may be presented to a user, e.g., as shown inFIG. 1. An exemplary manner in which water contaminant measurement system100may determine a concentration level of a preselected contaminant is provided in greater detail below.

FIG. 3provides a flow diagram of an exemplary method (300) for detecting and measuring a concentration level of a preselected contaminant in a volume of water according to an exemplary embodiment of the present subject matter. For instance, various components of the water contaminant measurement system100ofFIG. 1may detect and measure a concentration level of a preselected contaminant in a volume of water in accordance with method (300). Accordingly, general reference is made toFIG. 1and the reference numerals used to denote the features of water contaminant measurement system100will be utilized for context below.

At (302), the method (300) includes calibrating the system, and more particularly, calibrating a controller of the contaminant measurement system. An example manner in which the controller may be calibrated at (302) is provided below with reference to method (400) as depicted inFIG. 4.

With reference now toFIGS. 4, 5, and 6,FIG. 4provides a flow diagram of one exemplary method (400) in which a controller of a water contaminant measurement system may be calibrated at (302) of the method (300) ofFIG. 3according to an exemplary embodiment of the present subject matter.FIG. 5provides an exemplary graph illustrating an example implementation of method (400) according to an exemplary embodiment of the present subject matter.FIG. 6provides a table corresponding to the graph ofFIG. 5.

At (402), the method (400) for calibrating the controller includes performing a base measurement to ascertain a base reference parameter value indicative of the concentration level of the preselected contaminant in a volume of water having a first known concentration level of the preselected contaminant.

For instance, as shown in the example ofFIGS. 5 and 6, the first known concentration level of the preselected contaminant in the volume of water was selected as zero (0) ppm. Hence, the volume of water having the first known concentration level of the preselected contaminant had zero (0) ppm or a negligible amount of the preselected contaminant. To ascertain the base reference parameter, the volume of water having the first known concentration level was provided into chamber112of housing110. Detection agent130attempted to interact with the preselected contaminant from the volume of water having the first known concentration. As the volume of water having the first known concentration did not contain (or had a negligible amount of) the preselected contaminant, detection agent130did not interact with any ions of the preselected contaminant (or a negligible amount). One or more electric signals were received by controller150from sensing circuit140. The one or more electric signals were representative of the base reference parameter value indicative of the concentration level of the preselected contaminant in the volume of water having the first known solution. Controller150determined the base reference parameter value, e.g., via an analog reading chip. For the example ofFIGS. 5 and 6, the measured parameter is the voltage between first electrode141and second electrode142and the base reference parameter value was determined to be ten millivolts (10 mV) as shown in the table inFIG. 6. Accordingly, the voltage between first electrode141and second electrode142was ten millivolts (10 mV) for the volume of water having a concentration level of zero (0) ppm or a negligible amount of the preselected contaminant.

At (404), the method (400) for calibrating the controller includes performing one or more further measurements to ascertain one or more reference parameter values each indicative of the concentration level of the preselected contaminant in respective reference volumes of water each having a known concentration level of the preselected contaminant.

For the example ofFIGS. 5 and 6, a second measurement was performed to ascertain a second reference parameter value associated with a second volume of water having a second known concentration level of the preselected contaminant, a third measurement was performed to ascertain a third reference parameter value associated with a third volume of water having a third known concentration level of the preselected contaminant, a fourth measurement was performed to ascertain a fourth reference parameter value associated with a fourth volume of water having a fourth known concentration level of the preselected contaminant, and a fifth measurement was performed to ascertain a fifth reference parameter value associated with a fifth volume of water having a fifth known concentration level of the preselected contaminant.

The second measurement was performed to ascertain the second reference parameter value for the second volume of water having a second known concentration. To ascertain the second reference parameter value, the second volume of water having the second known concentration level was provided into chamber112of housing110(the first volume of water having the first known concentration level was first drained). Detection agent130interacted the preselected contaminant from the second volume of water having the second known concentration. The interaction between the detection agent130and the ions of the preselected contaminant as well as the reactions at the first and second electrodes141,142causes the reference parameter value (e.g., the voltage) to increase. One or more electric signals were received by controller150from sensing circuit140and controller150determined a second reference parameter value. For the example ofFIGS. 5 and 6, the measured parameter was selected as the voltage (e.g., the potential difference) between first electrode141and second electrode142and the second reference parameter value was determined to be fifty millivolts (50 mV). Thus, for this example, the voltage between first electrode141and second electrode142was determined to be fifty millivolts (50 mV) for a volume of water having a concentration level of one (1) ppm of the preselected contaminant. Notably, controller150determined the second reference parameter value at a time in which the measured voltage reached steady state. The measured voltage or parameter may fluctuate for a time period after the ions of the preselected contaminant within the second volume of water and detection agent130interact. Accordingly, the reference parameters are determined by controller150after equilibrium is achieved within chamber112and the reference parameter reaches steady state.

The same process was followed for the other reference parameters. For this example, the third known concentration level of the preselected contaminant in the third volume of water was ten (10) ppm and the third reference parameter value was measured at eighty millivolts (80 mV). The fourth known concentration level of the preselected contaminant in the fourth volume of water was one hundred (100) ppm and the fourth reference parameter value was measured at one hundred fifty millivolts (150 mV). The fifth known concentration level of the preselected contaminant in the fifth volume of water was one thousand (1,000) ppm and the fifth reference parameter value was measured at two hundred millivolts (200 mV). Although a total of five (5) measurements were performed in this example, it will be appreciated that more or less than five (5) measurements may be performed during calibration.

At (406), the method (400) for calibrating the controller further includes calculating a parameter difference value for the ascertained base reference parameter value and each of the plurality of ascertained reference parameter values. The parameter difference value for each of the plurality of ascertained reference parameter values is descriptive of the ascertained base reference parameter value subtracted from a given one of the ascertained reference parameter value. The parameter difference value for the base reference parameter value is zero (0), or the base reference parameter subtracted from the base reference parameter.

Continuing with the example ofFIGS. 5 and 6, the parameter difference value associated with the base parameter value (10 mV) was determined to be zero millivolts (0 mV). That is, the base reference parameter was subtracted from the base reference parameter (10 mV−10 mV=0 mV). The parameter difference value associated with the second parameter value (50 mV) was determined to be forty millivolts (40 mV). That is, the base reference parameter was subtracted from the second reference parameter (50 mV−10 mV=40 mV). The parameter difference value associated with the third parameter value (80 mV) was determined to be seventy millivolts (70 mV). That is, the base reference parameter was subtracted from the third reference parameter (80 mV−10 mV=70 mV). The parameter difference value associated with the fourth parameter value (150 mV) was determined to be one hundred forty millivolts (140 mV). That is, the base reference parameter was subtracted from the fourth reference parameter (150 mV−10 mV=140 mV). Finally, the parameter difference value associated with the fifth parameter value (200 mV) was determined to be one hundred ninety millivolts (190 mV). That is, the base reference parameter was subtracted from the fifth reference parameter (200 mV−10 mV=190 mV).

At (408), the method (400) for calibrating the controller includes determining a trend line specifying parameter difference values versus the concentration level based at least in part on the calculated parameter difference values. As shown in the graph ofFIG. 5, the calculated parameter difference values may be plotted on a graph as a function of concentration level and a trend line may be fit to the data points. In some implementations, the trend line may be a best-fit trend line. As will be explained in detail herein, the trend line may be utilized to calculate the concentration level of the preselected contaminant in a volume of water having an unknown concentration level.

Returning now toFIG. 3, once the system is calibrated at (302), e.g., via method (400), water contaminant measurement system100is now configured and operable to detect and measure the concentration level of a preselected contaminant in a volume of water having an unknown concentration level. Each water contaminant measurement system100may be calibrated as described above at (302), e.g., method (400), or in some implementations, other water contaminant measurement systems may be programmed or imaged with the trendline and values noted above. Thus, each water contaminant measurement system need not undergo calibration as described in method (400).

At (304), the method (300) includes selectively interacting a detecting agent immersed in a volume of water with the preselected contaminant in the volume of water for a first time period. For instance, the volume of water may have an unknown concentration level of the preselected contaminant. As one example, with reference toFIG. 1, a volume of water having an unknown concentration level of the preselected contaminant may be provided into chamber112of housing110. For instance, controller150may activate inlet valve118to move to an open position so that the water may flow from water source114to chamber112via inlet supply conduit116. When a predetermined volume of water having an unknown concentration level of the preselected contaminant has filled into chamber112, controller150may control inlet valve118to move to a closed position to prevent more water from flowing into chamber112. When the volume of water having an unknown concentration level of the preselected contaminant fills into chamber112, detecting agent130becomes immersed in the volume of water W and interacts with the preselected contaminant in the volume of water for a first time period. Of course, if the volume of water having the unknown concentration level of the preselected contaminant does not in fact contain the preselected contaminant, detecting agent130will not interact with the preselected contaminant.

In some implementations, the preselected contaminant is lead. In such implementations, detecting agent130is selected as polymeric beads132that are specifically designed to detect and w lead. The plurality of beads132may be treated with sodium hydroxide and may be polyacrylonitrile homopolymer beads. In some alternative implementations, the preselected contaminant may be another heavy metal, such as e.g., cadmium or chromium. In such implementations, the detecting agent130, which may be beads132, may be treated with other solutions and may have a different chemistry than the polymeric beads132specifically designed to interact with lead. In some further implementations, the contaminant may be phenols, pharmaceuticals, microbes, cysts, arsenic, and/or other undesirable substances or compounds.

At (306), the method (300) includes receiving, from a sensing circuit comprised of a first electrode and a second electrode both at least partially disposed in the volume of water, one or more electric signals. For instance, during or at the end of the first time period, controller150or measurement device180may receive the one or more electric signals from sensing circuit140that includes first and second electrodes141,142disposed within the volume of water in chamber112. The one or more electric signals are representative of a parameter indicative of the concentration level of the preselected contaminant in the volume of water W. For instance, the parameter may be a voltage, a current, an electrical conductance, or a resistivity. As noted previously, as detecting agent130interacts with the preselected contaminant (e.g., lead), the voltage across and the current flowing between the first and second electrodes141,142change. This also causes a change in the electrical conductivity of the water, or inversely, its resistivity. Thus, such electrical signals may be indicative of any one of these parameters. Based at least in part on the electric signals, e.g., the amplitude of the signals, a parameter value may be determined as discussed below at (308).

The one or more electric signals may be received by controller150or measurement device180at (306) continuously throughout the first time period, at a predetermined interval throughout the first time period (e.g., every five seconds), or only at the end of the first time period. The first time period may extend from a start time to an end time. In some implementations, the parameter value used to determine the concentration level of the contaminant in the volume of water within the chamber at (310) is based on one or more final signals of the one or more signals received at an end time of the first time period.

At (308), the method (300) includes determining a parameter value indicative of the concentration level of the preselected contaminant in the volume of water based at least in part on the one or more signals. For instance, upon receiving the one or more electric signals, controller150or measurement device180may determine or convert the one or more electric signals into a parameter value. For example, supposing the designated parameter is voltage, controller150may determine the voltage across first electrode141and second electrode142by converting the one or more electric signals into the voltage. As another example, supposing the designated parameter is current, controller150may determine the electrolytic current flowing between first electrode141and second electrode142by converting the one or more electric signals into the electric current. In some implementations, the parameter value is indicative of at least one of a voltage between the first electrode and the second electrode, an electrolytic current flowing between the first electrode and the second electrode, a conductivity of the volume of the water within the chamber, and a resistivity of the volume of water within the chamber.

Moreover, in some implementations, the end time of the first time period is associated with the determined parameter obtaining or reaching a steady state. Thus, in such implementations, the end time of the first time period is determined based on the determined parameter value reaching a steady state. For example, supposing the parameter is voltage, if the determined voltage maintains a value within a predetermined range for a predetermined time, controller150determines that the parameter has reached a steady state. Then, at (308), controller150may determine the parameter value based on the one or more final signals of the one or more signals received at an end time of the first time period.

At (310), the method (300) includes determining the concentration level of the preselected contaminant in the volume of water within the chamber based at least in part on the determined parameter value. For instance, the concentration level of the preselected contaminant in the volume of water W within chamber112may be determined based at least in part on the parameter value determined at (308). In some implementations, determining the concentration level of the preselected contaminant in the volume of water within the chamber based at least in part on the determined parameter value includes: calculating a parameter difference value for the determined parameter, wherein the parameter difference value for the determined parameter is descriptive of the ascertained base reference parameter value subtracted from the determined parameter value; and correlating the calculated parameter difference value for the determined parameter to the concentration level of the preselected contaminant in the volume of water within the chamber utilizing the determined trend line.

By way of example, with reference again toFIG. 5, suppose the parameter value determined at (308) is a voltage of one hundred sixty millivolts (160 mV). To determine the concentration level of the preselected contaminant (e.g., lead) in the volume of water W within chamber112based at least in part on the determined parameter value, a parameter difference value for the determined parameter value (one hundred sixty millivolts (160 mV)) is calculated. The parameter difference value for the determined parameter value is calculated in a similar fashion as the reference parameter values were calculated at (302) of method (300). In particular, the parameter difference value for the determined parameter value is descriptive of the ascertained base reference parameter value (e.g., as ascertained at (402) of method (400)) subtracted from the determined parameter value (e.g., as determined at (308) of method (300)). Thus, in this example, the parameter difference value for the determined parameter value is one hundred fifty millivolts (150 mV) as calculated by (160 mV-10 mV=150 mV).

Thereafter, the calculated parameter difference value (150 mV) for the determined parameter value is correlated to the concentration level of the preselected contaminant in the volume of water within the chamber utilizing the determined trend line. As shown inFIG. 5, the intersection of the calculated parameter difference value (150 mV) and the trend line TL determines the concentration level. The intersection of the calculated parameter difference value (150 mV) and the trend line TL is shown plotted on the graph inFIG. 5, and as depicted, the calculated parameter difference value (150 mV) correlates to a concentration level of about one hundred seventy (170) ppm. Accordingly, the volume of water W disposed in chamber112has concentration level of about one hundred seventy (170) ppm of the preselected contaminant (e.g., lead).

At (312), the method (300) includes outputting the determined concentration level of the preselected contaminant in the volume of water in the chamber. For instance, controller150may output the concentration level of the preselected contaminant in the volume of water W in chamber112as determined at (310) to display device160. In this way, the determined concentration level is presented to a user. For instance, for the example above, display device160may present the concentration level as one hundred seventy (170) ppm.

Further, in some exemplary implementations, method (300) includes applying a voltage across the first electrode and the second electrode both at least partially disposed in the volume of water within the chamber. For instance, power supply170may be positioned along sensing circuit140and may be configured to apply a voltage to the electrodes141,142, e.g., to better maintain the polarities of the electrodes141,142. In such implementations, the applied voltage must be taken into account when determining the concentration level of the preselected contaminant.

In some implementations, water contaminant measurement system100is configured to rapidly detect and measure a concentration level of a preselected contaminant in a volume of water. In short, in such implementations, one or more electric signals are received during the first time period (e.g., the time period in which detecting agent130interacts with the preselected contaminant), and as the signals are received, parameter values are determined and stored as data points. Based on the data points, controller150generates a parameter trend line specifying the determined parameter values over time. The parameter trend line is then used to predict a predicted parameter value in which the parameter will reach a steady state. In such implementations, the predicted parameter value is used to determine the concentration level of the contaminant in the volume of water within the chamber at (310).

By way of example, with reference now toFIG. 7,FIG. 7provides a graph depicting determined parameter values as a function of time. As depicted, in such implementations, the method (300) includes storing a plurality of data points representative of the determined parameter values over the first time period and plotting them as a function of time. The method (300) also includes generating a parameter trend line based at least in part on the stored and plotted plurality of data points. The parameter trend line may be calculated as a linear trend line, an exponential function, a polynomial function, a moving average, etc. InFIG. 6, the parameter trend line is generated as a decaying exponential function. In addition, the method (300) includes predicting the parameter value based at least in part on the parameter trend line. For the example depicted inFIG. 7, controller150predicts the parameter value as a value in which the parameter is predicted to reach a steady state, or stated differently, as a value in which the parameter trend line reaches a steady state. In this example, the parameter trend line is predicted to reach a steady state at a time t=tSS. The parameter value of the trend line at time t=tSSis determined as the predicted parameter value. In such implementations, the parameter value used to determine the concentration level of the contaminant in the volume of water within the chamber at (310) is based on the predicted parameter value. Advantageously, by predicting the parameter value at steady state, concentration level measurements may be output by controller150rapidly, e.g., within seconds, within thirty seconds, within minutes, etc. Thus, consumers may be made aware of potentially unsafe water more rapidly without need to wait hours or days with conventional systems.

In some implementations, controller150can include machine-learned model156(FIG. 2) that can be used to adjust the parameter trend line to more accurately predict the parameter value at steady state. In such embodiments, for example, the machine-learned model156can be adjusted based at least in part on validated parameter values. That is, the machine-learned model may adjust the parameter trend line based on the correlation between the predicted parameter values and the actual parameter values measured when the parameter has in fact reached steady state. The machine-learned model may also be trained and adjusted based on a plurality on measurement variables, such as e.g., the number of measurements performed by water contaminant measurement system100, the time in service of water contaminant measurement system100, the materials used for the electrodes, the spacing between the electrodes (i.e., the distance D), the water source, the number and type of detecting agents (e.g., the number of beads), the method in which the detecting agents are formed, the preselected contaminant, the volume of water used for sampling or determining the concentration level of the preselected contaminant, the measurement device or software program logic used for the measurements, whether a power source is utilized, and if so, the type of power rating the of power supply, etc.

The machine-learned model156can use any suitable machine learning technique to adjust the parameter trend line. For example, machine-learned model156can include a machine or statistical learning model structured as one of a linear discriminant analysis model, a partial least squares discriminant analysis model, a support vector machine model, a random tree model, a logistic regression model, a naïve Bayes model, a K-nearest neighbor model, a quadratic discriminant analysis model, an anomaly detection model, a boosted and bagged decision tree model, an artificial neural network model, a C4.5 model, a k-means model, or a combination of one or more of the foregoing. Other suitable types of machine or statistical learning models are also contemplated. It will also be appreciated that the machine-learned model156can use certain mathematical methods alone or in combination with one or more machine or statistical learning models to adjust the parameter trend line.

The water contaminant measurement system and methods described herein provide a number of advantages and benefits. For instance, the water contaminant measurement system and methods described herein provide a relatively low cost measurement system and techniques that allow for rapid, onsite concentration level measurements to be determined. Thus, reliance on costly conventional systems that require long measurement turnaround times is reduced. The water contaminant measurement system and methods described herein may be utilized for point of entry applications, point of use applications, in water treatment and processing facilities, in homes and buildings, and may be integrated or in line with filter devices. Further, the water contaminant measurement system and methods described herein may be utilized to detect any suitable preselected contaminant, such as e.g., lead, cadmium, chromium, as well as other contaminants. By changing the chemistry or treatment of the detecting agent, the concentration level of any suitable contaminant may be measured and presented to a user. Other benefits and advantages not specifically listed herein are possible.