The invention relates to a system for determining a level of nitrate in a water sample, including: (a) an optical flow cell which is at least partially transparent and which is configured to contain a sample of water; (b) a first illuminator for illuminating the sample by light in a first wavelength, and a first photodetector for collecting the first-wavelength illumination, following the light passage through the sample; (c) a second illuminator for illuminating the sample within the cell by light in a second, fluorescence-exciting wavelength, and a second photodetector for collecting illumination in a third, fluorescence-emission wavelength from the sample; and (d) an analysis unit for determining the combined effect of nitrate+DOC within the sample on the absorbance of light, determining a concentration of DOC within the sample based on fluorescence emission from the sample, and subtracting the effect of DOC from the combined effect of nitrate+DOC on the absorbance, thereby to determine a concentration of nitrate within the sample.

A method of application to provide a workable solution for tracking the hardness of water utilizing an ion selective electrode by tracking the relative hardness of water at the outflow or egress of an ion exchange column. A monovalent cation exchange membrane (ion selective electrode) distinguishes hard water and softened water in a water flow stream. A voltage is applied across the membrane, facilitating the movement of sodium though the membrane (such that anions and divalent ions are excluded), and the current is measured. The change in current (delta current) is used to determine the hard water concentration or level of hardness in an influent stream. A second application estimates or detects the exhaustion of an ion exchanger, and/or determines the regeneration time/cycle of the ion exchanger through the use of an ion selective membrane. Blending of the influent hard water and effluent soft water allows a user to control hardness levels of the effluent.

A flow-through measuring station includes at least one flow cell having a fluid channel. The fluid channel has a fluid inlet and a fluid outlet and is configured to conduct a liquid medium. One or more flow cells each include at least one sensor configured to be contacted with the medium and to determine at least one respective media property. At least one illumination unit is configured to indicate a respective state of at least one sensor. The measuring station also includes a transmitter/measuring transducer which is configured to operate the at least one sensor and the at least one illumination unit, and to determine in each case a state of at least one sensor.

A water monitoring device monitors and maintains swimming pool chemistry. The device mixes reagents with water in flowcells. The water chemistry is detected by measuring the light transmitted through the flowcells. The water monitoring device can communicate with computers, servers and mobile computing devices which can store and display the water chemistry information. The reagents can be stored in a replaceable reagent cartridge which can provide reagents for water testing and can be replaced when the reagents need to be replenished.

A sensor assembly having a housing including a plurality of compartments, an actuator for selectively hermetically sealing or fluidly connecting the plurality of compartments, a plurality of sensors each positioned in a corresponding compartment, and a receiver is disclosed. A method of monitoring a parameter of a fluid in a remote location is also disclosed. The method includes deploying the sensor assembly to the remote location, fluidly connecting a first sensor to the fluid, transmitting to an external controller data including values for the measured parameter of the fluid, and operating the actuator to fluidly connect a second sensor responsive to the operating interval of the first sensor trending to expiration. A sensing system having a sensor assembly and an external controller is also disclosed. A method of facilitating monitoring a parameter of the fluid in a remote location by providing the sensor assembly is also disclosed.

Methods and systems are provided for verifying hygienic hand cleaning including a wash basin, having a contaminant sensor positioned in proximity to a drain of the wash basin, to measure a level of contamination of rinse fluid leaving the wash basin; and a processor and associated memory having instructions that when executed by the processor implement: receiving a signal from the contaminant sensor indicative of the level of contamination; and responsively, determining the level of contamination and comparing the level of contamination with a contamination threshold to determine a hand washing status.

An illustrative embodiment of a flow cell may include a main chamber, base plate, and cover. The main chamber may be formed with an interior portion having a first angled surface, a first ramp, a second ramp, and a second angled surface. A secondary drain may be positioned at a point of relatively low elevation between the bottom portions of the first and second ramps. The main chamber may include first, second, and third inlet passages that may be in fluid communication with an inlet header formed in the base plate. A PLC and/or PAC may be in communication with various components of the flow cell and/or external components for monitoring, sensing, and/or providing other functionality.

A streaming current measurement flow cell, free from potential piston-to-electrode contact, with a flexible, but close-fitting piston and sleeve set, wherein a housing-defined bushing, as it encircles the piston's active segment near its upper end, does so with a short, cylindrical sidewall, the inside diameter of which, in comparison to the active segment's diameter, creates a narrower—but by only 0.002 inch—capillary-sized flow channel between the bushing and the active segment than exists between it and the sleeve. Even so, physical contact between piston and sleeve—a major wear factor—is completely eliminated; and larger particles known to scratch/gouge dielectric surfaces are kept out of the piston/sleeve flow channel. Moreover, a limitation on the piston's downward travel wherein the active segment's upper end is brought just flush with the upper electrode's flat, annular face makes possible a novel system, critical in self-cleaning this electrode where its inner edge and setback are exposed atop the bushing.

A system for product water output. The system includes a controller, a first conductivity sensor in communication with the controller, a first product valve downstream from the first conductivity sensor and in communication with the controller, a second product valve downstream from the first product valve and in communication with the controller, a second conductivity sensor downstream from the second product valve and in communication with the controller, and a divert valve downstream from the first conductivity sensor and upstream from the first product valve and in communication with the controller.

An illustrative embodiment of a flow cell may include a main chamber, base plate, and cover. The main chamber may be formed with an interior portion having a first angled surface, a first ramp, a second ramp, and a second angled surface. A secondary drain may be positioned at a point of relatively low elevation between the bottom portions of the first and second ramps. The main chamber may include first, second, and third inlet passages that may be in fluid communication with an inlet header formed in the base plate. A PLC and/or PAC may be in communication with various components of the flow cell and/or external components for monitoring, sensing, and/or providing other functionality.