Patent Description:
The systems and methods provided herein relieve the operator of the above challenges and provide automated or "hands-off" operation, requiring only setup. In fully automated employment, all that may be required is for the operator to collect a ready to transport sample upon alert that the sample is ready to be collected. The systems and methods described herein facilitate time-, labor-, and cost-efficiencies to sample and perform real-time monitoring at multiple sites, such as geographically separated wells, simultaneously. This results in a tremendous savings of effort and time. The systems and methods described and claimed herein further provide the ability to efficiently monitor groundwater contamination by at least partially automating the fluid collection process. Before fluids can be collected for subsequent analysis, including at an off-site lab having the ability to precisely quantify a range of chemical species, ranging from volatile organic compounds to inorganic metals, the fluid must be "clean". In particular, the fluid in the well should be purged in order to obtain an accurate measure of groundwater contamination and avoid measuring initial fluids that tend to build-up and store contaminants so that a reading of those samples is not a true indication of environmental groundwater contamination level. The systems and methods provided herein automate this procedure so that an operator need not be on-site adjusting pump flow-rate, calculating water parameters, and deciding when stabilization is achieved. Instead, the operator may be alerted, such as via a wireless communication to a hand-held device on the person of the operator, that sample stabilization is achieved and fluid (e.g., water) collection may begin. In this manner, significant time savings and efficiencies are achieved, even while reducing the likelihood of errors caused by operator error, including arising from tracking many water quality parameters over time to determine when sampling may occur. The systems and methods similarly free the operator from being tied to specific testing sites for specific times, thereby further increasing flexibility and efficiency.

The systems and methods may be incorporated with a wireless network enabled device (also generally referred herein is a communication device capable of receiving data from any one or more components of the system), thereby providing a convenient platform for remotely reviewing flow-rate, drawdown, pump status, and any other parameters of interest. Accordingly, any of the low flow pumps may be a Bluetooth enabled pump, for instance, thereby facilitating wireless communication and control.

The systems and methods may be used with any of a range of water quality sondes, including any of the sensors and/or multiparameter sondes described in <CIT>), <CIT>), <CIT>), each of which are incorporated by reference in their entirety to the extent not inconsistent herewith.

Any of the systems and methods may incorporate auto-calibration of the sensors, run stabilization routines, and sample auto-collection. Notification may be automatically sent as an alert that the samples are ready for pickup and/or waste water is ready to be disposed of. A mobile app may interface with the water quality sonde (e.g., sensors) to automatically calculate stabilization and collect other pieces of information.

Provided herein are low flow groundwater fluid sampling systems. The system may comprise: a low flow pump; a flow cell in fluid and/or electronic communication with the low flow pump, wherein the flow cell comprises one or more fluid quality sensors; a waste container in fluid communication with the flow cell for collecting a waste fluid, wherein the waste container comprises a level sensor for measuring a waste fluid depth in the waste container; a communication device in wireless communication with each of the pump, flow cell and waste container, wherein the low flow pump has an adjustable pump power to provide a desired constant flow-rate to the flow cell from the electronic communication between the low flow pump and the level sensor and the at least one fluid quality sensor measures one or more fluid parameters over a time course to assess fluid stabilization status; upon fluid stabilization the communication device indicates an affirmative fluid stabilization condition and that a fluid sample may be collected; and all fluid provided to the flow cell by the low flow pump is either collected in a fluid sample or directed to the waste container and collected as the waste fluid.

The systems provided herein are compatible with any of a range of flow sensors incorporated or positioned anywhere in the system, so long as a flow-rate can be determined and used to control pump power so as to maintain a desired flow-rate through the system. For example, the waste container level sensor itself can be used as a type of flow sensor, wherein the change in volume of waste fluid as a function of time provides a measure of flow-rate for controlling the adjustable pump power. Similarly, a separate flow sensor may be used upstream from the flow cell, downstream from the flow cell, or within the flow cell, to provide a measure of flow-rate used to control or adjust pump power, so as to maintain a desired, substantially constant, flow-rate.

Accordingly, any of the systems may further comprise a flow sensor in fluid and electronic communication with the low flow pump.

The system may further comprise an autosampler in fluid communication with the flow cell, wherein an output flow from the flow cell for an affirmative fluid stabilization condition is directed to the autosampler for collection. In this manner, an operator need not be physically on-site in order to collect a fluid sample. Instead, an operator or other individual, when convenient, can go to the site and pick-up the samples from the collector for subsequent off-site transport.

The flow cell may comprise a multi-parameter sonde having a plurality of fluid quality sensors. In this manner, a plurality of fluid parameters may be monitored, thereby providing improved liquid assessment fidelity and assurance that an affirmative fluid stabilization condition is reached. Fluid quality sensors include any one or more selected from the group consisting of: a turbidity sensor, a pressure sensor, a temperature sensor, an electrical conductivity sensor, a pH sensor, an electrochemical sensor such as an oxidation reduction potential (ORP) sensor, a fluorescence sensor, and any combination thereof.

Any of the systems may further comprise a depth sensor for assessing fluid draw-down level in a monitoring well, wherein the depth sensor is: in wireless communication with the communication device; electronic communication with the pump; or in communication with both.

Any of the flow cells provided herein may further comprise an auto-calibrator for automatically calibrating the one or more fluid quality sensors. For example, the auto-calibrator may have calibrated solutions with a known fluid parameter magnitude, including different solutions spanning a range of fluid parameter magnitudes, with automated introduction of calibration solutions to provide a type of calibration curve to calibrate the sensor over a range of values prior to introduction/ of groundwater. Alternatively, the flow cell may be calibrated before being used in any of the processes described herein. Accordingly, for a collected fluid sample, a wide range of fluid quality parameters may be reliably measured for the fluid sample.

The systems and methods provided herein are compatible with a range of flow-rates, depending on the application of interest, such as related flow characteristics in and around a test well. For example, the desired or constant flow-rate may be greater than or equal to <NUM>/min and less than or equal to <NUM>/min.

The waste container level sensor may comprise a pressure transducer at a bottom surface of the waste container to measure waste fluid level in the waste container. Other examples include optical-type sensors that optically measure a path length or change in an optical property, thereby detecting fluid level. With a waste fluid height detected, the volume is determined for a known cross-sectional area of the waste container. A mass sensor may be used to measure the mass of liquid provided to the waste container, so that for a known liquid density, flow-rate is readily determined.

In any of the systems provided herein, one or more of a fluid flow-rate or a water well depth is transmitted to the communication device and a control signal is transmitted from the communication device to the low flow pump to maintain the desired or constant fluid flow-rate and/or a water well depth.

In any of the systems provided herein, a measured waste fluid depth may be wirelessly transmitted to the communication device. The communication device may then provide an alert to a user, such as a waste fluid alarm for a waste fluid depth that is greater than or equal to a waste fluid depth maximum. In this manner, overfilling of the waste fluid container is avoided. The waste fluid depth maximum may be less than the depth of the waste container, so as to provide time to an operator before the container overfills and to provide the ability to handle the waste container without spilling. For example, the waste fluid depth maximum may correspond to about <NUM>% to <NUM>% of the waste container depth, such as between <NUM>% and <NUM>%, and any sub-ranges thereof.

The communication device may comprises a mobile smartphone, a handheld portable device, or a computer.

The communication device may comprise a telemetry system positioned for transmitting data to a mobile device or a remote monitoring station.

The systems provided herein can be part of a multiplexed system comprising a plurality of the low flow groundwater sampling systems for simultaneously monitoring of a plurality groundwater wells. In this manner, one operator may manage and monitor fluid collection substantially simultaneously over a wide geographic range.

The systems provided herein are compatible with a range of applications, including for use in a groundwater contamination application, wherein a clean fluid sample is used for off-site testing of said clean fluid sample. Clean refers to a sample that has been appropriately validated as being in an affirmative fluid stabilization condition, as determined by the sensors in the flow-cell.

The groundwater contamination application may further comprise monitoring oil or gas, or byproducts thereof, for groundwater contamination.

Also provided herein are methods for collecting fluid samples using any of the systems described herein.

For example, a method for collecting low flow fluid samples from groundwater may comprise the steps of: continuously pumping a flow of groundwater fluid to a flow cell at a substantially constant flow-rate; measuring a fluid quality parameter time course with a fluid sensor in said flow cell; identifying a positive fluid quality stabilization status for said measured fluid quality parameter that reaches a steady-state value; and wirelessly transmitting a signal to a communication device indicating a fluid sample is ready to be collected from said flow of groundwater fluid.

The method may further comprise the step of manually collecting the fluid sample after the fluid stabilization is achieved.

The method may further comprise the steps of collecting a waste fluid that exits said flow cell in a waste container; and monitoring a waste fluid level with a level sensor connected to the waste container.

Any of the methods may be used with an autosampler, such as by activating an autosampler to automatically collect fluid sample that exits the flow cell after the positive or affirmative fluid quality stabilization status is identified.

The method may be used for simultaneous collection of a plurality of low flow fluid samples from a plurality of wells, such as by a multiplexed connection of a plurality of the systems described herein, with one system provided per well.

The continuously pumping may be by a low-flow pump fluidly connected or in fluid contact with a sample well.

The sample well may be configured to monitor contamination of ground water, including oil or gas contamination, heavy metal contamination, solvent contamination, or contamination of a material from an industrial process.

Any of the methods may further comprise the step of auto-calibrating the fluid sensor before the measuring step by: flushing the flow cell with a clean fluid, such as water; filling the flow cell with a calibration solution; measuring a calibration fluid quality parameter with the fluid sensor until stability is reached; calculating a new calibration coefficient for the fluid sensor; storing the new calibration coefficient for a subsequent fluid test measurement; and repeating until all water quality parameters for all fluid sensors are calibrated.

The continuously pumping may be automated or semi-automated by measuring fluid flow through said flow cell and/or measuring a fluid depth in a sample well, wherein the measured fluid flow and/or fluid depth generates an output that is provided as an input to said low flow pump to control pump power, thereby controlling fluid flow in a feedback loop so as to maintain constant flow-rate and/or fluid depth in said sample well.

Provided herein are various low flow groundwater fluid sampling systems, including those comprising: a low flow pump; a flow cell in fluidic and electronic communication with said low flow pump, wherein said flow cell comprises one or more fluid quality sensors; a waste container in fluid communication with said flow cell for collecting a waste fluid, wherein said waste container comprises a level sensor for measuring a waste fluid depth in said waste container; an autosampler in fluid communication with said flow cell, wherein an output flow from said flow cell for said affirmative fluid stabilization condition is directed to said autosampler for collection, wherein: a communication device is in communication, including wireless communication, with each of said pump, flow cell and waste container; said pump has an adjustable pump power to provide a desired constant flow-rate to said flow cell from said electronic communication between said low flow pump and said flow sensor and said at least one fluid quality sensor measures at least one or more fluid parameters over a time course to assess fluid stabilization status; upon fluid stabilization said communication device actuates said autosampler to collect a fluid sample; all fluid provided to said flow cell is either collected in a fluid sample or directed to said waste container and collected as said waste fluid; and said communication device is configured to generate a sample ready signal to a user or operator upon collection of said fluid sample. In this manner, all that is required of the user or operator is to collect the fluid sample for transport to an off-site testing facility.

Any of the systems may comprise a sampling controller for implementing any of the control schemes described herein. For example, the sampling controller may be part of, or operably connected to, the communication device.

Also provided are systems for sampling or monitoring groundwater, optionally under low-flow conditions, the system comprising: a flow cell including at least one fluid quality sensor; a pump in flow communication with the flow cell; a flow sensor in flow communication with the flow cell; a pump controller for regulating a fluid flow-rate from a groundwater source to the flow cell, the pump controller operatively coupled to the pump; and a sampling controller for implementing a control scheme for the groundwater sampling system, the sampling controller communicatively coupled to: the flow sensor, the at least one fluid quality sensor, and the pump controller. The control scheme may include: (a) transmitting a control signal to the pump controller in response to signals received from the flow sensor to facilitate maintaining a substantially constant fluid flow-rate from the groundwater source to the flow cell; (b) determining one or more fluid parameters over a time course based on signals received from the at least one fluid quality sensor; (c) determining a fluid stabilization status of groundwater flowed to the flow cell by the pump based on the one or more fluid parameters determined in (b); and (d) in response to an affirmative fluid stabilization condition being determined in (c), initiating collection of at least one fluid sample of the groundwater under test. As described, the collection may be into a sample container for subsequent transport and testing in an off-site testing facility. The collection may be automated or manual.

Any of the systems described herein optionally include a waste container in flow communication with the flow cell, wherein the flow sensor is a depth sensor positioned in the waste container configured to measure the amount of waste fluid collected in the waste container. In this manner, the flow-rate is determined by the change in the volume of waste fluid with time, thereby avoiding a need for a separate flow sensor. Of course, any of the systems and methods described herein are compatible with one or more flow sensors positioned at distinct locations, such as upstream and/or downstream of the flow cell, or within the flow cell itself, to provide additional monitoring capability, quality control and troubleshooting. Similarly, any one or more additional flow components may be utilized, such as filters, pressure sensors, valves, and the like. A filter is optionally utilized near an inlet to the system, to further minimize risk of clogging and fouling.

The flow sensor may be positioned upstream of an inlet of the flow cell; the fluid flow-rate from the groundwater source to the flow cell is a first fluid flow-rate of the groundwater under test into the inlet; the system may further comprise an outlet flow sensor for measuring a second flow-rate of the groundwater under test out of an outlet of the flow cell, the outlet flow sensor positioned proximal the outlet and communicatively coupled to the sampling controller; and the control scheme further includes: (e) comparing a measured value of the second flow-rate to a measured value of the first flow-rate to determine a difference therebetween.

The system may further comprise a waste container in flow communication with the flow cell for collecting a waste fluid; a first valve positioned upstream of the inlet and in flow communication with the pump, the flow cell, and the waste container; and a first valve controller for alternately directing flow of groundwater from the groundwater source to one of at least two flow paths, the first valve controller operatively coupled to the first valve, the at least two flow paths including: a first flow path from the pump to the flow cell, and a second flow path from the pump to the waste container.

The control scheme may further include: (f) in response to a value of the difference determined in (e) being greater than or equal to a predetermined flow-rate difference, transmitting a control signal to the first valve controller to facilitate diverting the flow of groundwater from the pump to the second flow path.

The system may further comprise: a second valve positioned downstream of the outlet and in flow communication with the flow cell and the waste container; and a second valve controller for alternately opening and closing the second valve to facilitate alternately starting and stopping, respectively, flow of groundwater into or out of the outlet, the second valve controller operatively coupled to the second valve.

The control scheme may further include: (g) in response to a value of the difference determined in (e) being greater than or equal to a predetermined flow-rate difference, transmitting a control signal to the second valve controller to facilitate closing the second valve and stopping flow of groundwater into the outlet.

The system may further comprise: a waste container in flow communication with the flow cell for collecting a waste fluid; a second valve positioned downstream of the outlet and in flow communication with the flow cell and the waste container; and a second valve controller for alternately directing flow of groundwater from the flow cell to one of at least two flow paths, the second valve controller operatively coupled to the second valve, the at least two flow paths including: a first flow path from the flow cell to the at least one fluid sample, and a second flow path from the flow cell to the waste container.

The control scheme may further include: (i) transmitting a control signal to the second valve controller to facilitate diverting the groundwater under test to the first flow path to further facilitate collecting the at least one fluid sample.

Any of the systems may further comprise an autosampler for collecting a plurality of fluid samples, the autosampler including: a sample platform, and an electric motor operatively coupled to the sample platform, and a motor controller operatively coupled to the motor, the motor controller communicatively coupled to the sampling controller, and wherein, for (d), with the control scheme further including: (i) for at least one iteration: transmitting a control signal to the motor controller to facilitate incrementally moving the sample platform from a position of a first container for containing a first fluid sample to at least a second container for containing at least a second fluid sample.

The at least one of: the flow sensor, the at least one fluid quality sensor, and the pump controller, may be wirelessly communicatively coupled to the sampling controller.

The at least one fluid quality sensor may include at least one of: a turbidity sensor, a pressure sensor, a temperature sensor, a dissolved oxygen sensor, an oxidation reduction potential sensor, and a fluorescence sensor.

The sampling controller may comprise a computing device, the computing device including: a processor, and memory communicatively coupled to the processor; and the computing device implements the control scheme for the system.

The memory device may include a non-transitory computer readable medium storing processor-executable instructions encoded as software, which, when executed by the processor, cause the processor to implement the control scheme for the system.

The flow sensor, the at least one fluid quality sensor, and the pump controller, may be wirelessly communicatively coupled to the computing device.

The computing device may be a mobile device, such as a smartphone; and the software includes a smartphone app. In this manner, an operator may be untethered to a specific location, and can conveniently move about the day, wherein in conventional systems, substantial time was devoted to being onsite to control the process and ensure appropriate samples were collected.

Any of the systems and methods may comprise an autosampler, such as an autosampler having: a sample platform, and an electric motor operatively coupled to the sample platform, and a motor controller operatively coupled to the motor, the motor controller communicatively coupled to the sampling controller. The control scheme may further include: for at least one iteration: transmitting a control signal to the motor controller to facilitate incrementally moving the sample platform from a position of a first container for containing a first fluid sample to at least a second container for containing at least a second fluid sample. In this manner, fluid samples may be periodically collected and ready for pick-up and transport to a testing facility.

Also provided is a method for monitoring groundwater comprising: (A) flowing, by a pump operatively coupled to a pump controller, groundwater under test from a groundwater source to a flow cell in flow communication with the pump, the flow cell including at least one fluid quality sensor; (B) collecting at least one fluid sample of the groundwater under test from an output flow of the flow cell; and (C) controlling, by a sampling controller, the pump controller to facilitate regulating a fluid flow-rate from a groundwater source to the flow cell, wherein the sampling controller is communicatively coupled the pump controller and communicatively coupled to a flow sensor positioned upstream of the flow cell and positioned downstream of the pump, the controlling step comprising: (i) transmitting, by the sampling controller, a control signal to a pump controller in response to signals received from the flow sensor to facilitate maintaining a substantially constant fluid flow-rate from the groundwater source to the flow cell; (ii) determining one or more fluid parameters of the groundwater under test over a time course based on signals received from the at least one fluid quality sensor; (iii) determining a fluid stabilization status of the groundwater under test based on the one or more fluid stabilization parameters determined in (ii); and (iv) in response to an affirmative fluid stabilization condition being determined in (iii), initiating collections of at least one fluid sample of the groundwater under test.

The flow sensor may be a first flow sensor positioned upstream of an inlet of the flow cell; the fluid flow-rate from the groundwater source to the flow cell is a first fluid flow-rate of the groundwater under test into the inlet; wherein the system further comprises an outlet flow sensor for measuring a second flow-rate of the groundwater under test out of an outlet of the flow cell, the outlet flow sensor positioned downstream of the first flow sensor and proximal the outlet, the outlet flow sensor communicatively coupled to the sampling controller; and the controlling step further comprises: (v) receiving signals from the outlet flow sensor for measuring a second flow-rate of the groundwater under test out of an outlet of the flow cell; and (vi) comparing a measured value of the second flow-rate to a measured value of the first flow-rate to determine a difference therebetween.

The controlling step may further comprise: (vii) in response to a value of the difference determined in (vi) being greater than or equal to a predetermined flow-rate difference, transmitting a control signal to the pump controller to facilitate at least one of: stopping operation of pump, decreasing the first flow-rate.

The controlling step may further comprise: (v) receiving signals from a waste container sensor for measuring a waste fluid depth of a waste container in flow communication with the flow cell for collecting a waste fluid, wherein the waste container sensor is positioned in the waste container, and wherein the waste container sensor is communicatively coupled to the sampling controller; (vi) determining a value of the waste fluid depth based on the signals received from the waste container sensor; and (vii) in response to the waste fluid depth value determined in (vi) being greater than or equal to a predetermined waste depth value, at least one of: a) transmitting a control signal to the pump controller to facilitate stopping operation of pump or decreasing the fluid flow-rate; and b) providing an alarm.

The collecting step may further include collecting a plurality of fluid samples of the groundwater under test using an autosampler.

Also provided herein are systems for performing any of the methods described herein.

Also provided herein is a non-transitory computer readable medium storing processor-executable instructions for implementing a control scheme of a groundwater sampling or monitoring system, which, when executed by a processor of the groundwater sampling or monitoring system, cause the processor to: flow, by a pump operatively coupled to a pump controller, groundwater under test from a groundwater source to a flow cell including at least one fluid quality sensor, wherein the pump controller, the at least one fluid quality sensor, and a flow sensor positioned upstream of the flow cell and downstream of the pump are communicatively coupled to the processor; collect at least one fluid sample of the groundwater under test from an output flow of the flow cell; and control the pump controller to facilitate regulating a fluid flow-rate from the groundwater source to the flow cell, wherein, when executed by the processor to control the pump controller, the processor-executable instructions further cause the processor to: (i) transmit a control signal to a pump controller in response to signals received from the flow sensor to facilitate maintaining a desired or constant fluid flow-rate from the groundwater source to the flow cell; (ii) determine one or more fluid parameters over a time course based on signals received from the at least one fluid quality sensor; (iii) determine a fluid stabilization status of groundwater flowed to the flow cell by the pump based on the one or more fluid stabilization parameters determined in (ii); and (iv) in response to an affirmative fluid stabilization condition being determined in (iii), initiate collection of at least one fluid sample of the groundwater under test.

Without wishing to be bound by any particular theory, there may be discussion herein of beliefs or understandings of underlying principles relating to the devices and methods disclosed herein. It is recognized that regardless of the ultimate correctness of any mechanistic explanation or hypothesis, an embodiment of the invention can nonetheless be operative and useful.

In general, the terms and phrases used herein have their art-recognized meaning, which can be found by reference to standard texts, journal references and contexts known to those skilled in the art. The following definitions are provided to clarify their specific use in the context of the invention.

"Low flow groundwater" refers to water samples that reflect total mobile organic and inorganic loads that are transported through the subsurface under ambient flow conditions. Typical applications herein that rely on low flow groundwater are monitoring wells that are drilled for the purpose of monitoring contamination, including contaminants associated with the oil and gas industry or, more generally, any chemical manufacturing or processing application. Accordingly, the monitoring well may be anywhere oil and gas is commercially present, including production sites, storage sites, gas stations, transportation (e.g., pipelines), manufacturing, refining, and the like. Of course, the systems and methods provided herein are versatile, and may be incorporated and located for any of a range of applications where fluid (liquid) sampling is desired for subsequent off-site analysis, such as in a testing facility having instrumentation, sensitivity and/or cost-efficiency not readily available in the field.

"Low flow pump" is used broadly to refer to pumps that are designed to provide relatively low flow-rates, such as less than <NUM>/min, or between <NUM>/min to <NUM>/min. The actual flow-rate range is selected so as to ensure there is minimal disturbance of the well to minimize unwanted particulate mixing with the water that has naturally flowed to the monitoring well, resulting in unwanted effects including on turbidity measurement. In addition, the low flow-rates maintain low water-level drawdowns. A low and steady flow-rate generated by the low-flow pump allows for monitoring of water parameters in order to determine when sampling may begin. Any of a range of pumps, such as adjustable rate, peristaltic, submersible, centrifugal, bladder and the like may be used. The pump may be placed downhole and configured to be submersed in water. Alternatively, the pump may be placed out of the water, with tubing provided between the water and pump for steady withdrawal of water. The pump may be adjusted to ensure there is minimal water level drawdown in the well, such as less than about <NUM> feet, or a draw down level that remains constant or substantially constant.

The samples that are properly collected are suitable for analysis of groundwater contaminants such as volatile and semi-volatile organic analytes, dissolved gases, pesticides, PCBs, metals, other inorganics of interest or naturally occurring analytes. The collected samples may be transported to a testing facility for precise testing of any one or more materials, including to assess groundwater contamination. Preferably the pump is made of a material, or has a coating, so that there is minimal leaching for pumps that are submersed in the water, thereby minimizing risk of unwanted self-contamination.

"Desired constant flow-rate" refers to a user-determined flow-rate that will result in good purging and subsequent suitable fluid for collection and subsequent sampling. Preferably, the desired constant flow-rate is selected so that there is not an undue fluid drawdown from the well and that the natural inflow of water balances the fluid pumped out of the well. Typical flow-rate values are less than <NUM>/min, such as between <NUM>/min and <NUM>/min. Accordingly, the desired constant flow-rate may be greater than or equal to <NUM>/min and less than or equal to <NUM>/min, or any subranges thereof. "Constant", in this context, is used broadly and refers to the goal that flow-rate remains relatively steady, recognizing it is not practical, especially in the field, to achieve an exact non-deviating constant. Instead, practical realities such as related to fluid level fluctuations, pump power fluctuations, obstructions, disturbances and any of a variety of other external factors, will result in some deviation from constant. Accordingly, desired constant flow-rate may refer to a timeaveraged flow-rate with a standard deviation or, more simply a maximum deviation, that is within <NUM>%, <NUM>% or <NUM>% of the mean or desired flow-rate. If the measured flow-rate then falls outside such a standard deviation or has a maximum deviation outside of <NUM>%, <NUM>% or <NUM>%, the flow may be considered not constant, and the system continues to pump until a sufficient duration of a desired constant flow-rate is achieved. That duration may be selected as greater than or equal to <NUM> minute, <NUM> minutes, <NUM> minutes, <NUM> minutes, or <NUM> hour. In this aspect, "constant flow-rate" may be used interchangeably with "substantially constant flow-rate" to reflect there is some tolerance in sample collection to minor variations in flow-rate, such as a mean flow-rate with a standard deviation that is within <NUM>%, <NUM>% or <NUM>% of the mean flow-rate or a maximum deviation that is within <NUM>%, <NUM>% or <NUM>% of the mean or desired flow-rate.

The "flow cell" directs pumped fluid over one or more "fluid quality sensors". As discussed, any one or more of the sensors or sondes, including a multiparameter sonde, of<CIT>, Atty Ref. <NUM>: <NUM>-<NUM>), <CIT>, <CIT>; and <CIT>; <CIT>, <CIT>, are incorporated by reference, including for use in flow cells or any other position where a liquid parameter is desirably measured. See also, In-Situ, Inc. "Low flow kits and accessories" available at in-situ. com/wp-content/uploads/ <NUM>/<NUM>/LowFlow_Kits_2017. <NUM>), for exemplary low-flow kits, components and accessories.

"Steady-state" or "stabilization" refers to one or more fluid quality sensors achieving a stable read-out of the one or more water quality parameters. Examples of fluid quality sensors include turbidity, temperature, specific conductance, pH, oxidation-reduction potential (ORP), and dissolved oxygen (DO). Stabilization can be defined by a user or may be a rule or regulation implemented by a government agency or standard setting body, and generally refers to multiple consecutive measurements that have a substantially constant measured water quality parameter. The invention is compatible with any number or types of stabilization definitions. For example, stabilization may refer to a deviation, such as maximum deviation, standard deviation, or the like, over a number of consecutive measurements or a time frame, such as three or more consecutive measurements or a time period that is greater than a user-specified amount. The specific definition of stabilization can be from a regulation, such as US EPA EQASOP-GW4 "Low stress (low flow) purging and sampling procedure for the collection of groundwater samples from monitoring wells" Rev. <NUM> Sept. <NUM>, <NUM> (EPA <NUM>). For example: "Stabilization is considered to be achieved when three consecutive readings are within the following limits: Turbidity (<NUM>% for values greater than <NUM> NTU; if three Turbidity values are less than <NUM> NTU, consider the values as stabilized), Dissolved Oxygen (<NUM>% for values greater than <NUM>/L, if three Dissolved; Oxygen values are less than <NUM>/L, consider the values as stabilized), Specific Conductance (<NUM>%), Temperature (<NUM>%), pH (± <NUM> unit), Oxidation/Reduction Potential (±<NUM> millivolts). " EPA <NUM> is specifically incorporated by reference herein, including for the various definitions of "stability" for the different liquid quality parameters.

Whether the measurement has achieved "stability" or is "stable" depends, at least in part, on the sensitivity, reliability and reproducibility of the underlying sensor, as well as the particular application and corresponding liquid quality characteristics. For example, fluids having high turbidity may have a higher variability in measurements than lower turbidity. Stability may be considered achieved for turbidity variation of less than <NUM>%, dissolved oxygen of less than <NUM>%, specific conductance of less than <NUM>%, temperature of less than <NUM>%, pH variation of less than <NUM>, and/or ORP variation of less than <NUM> mV. The variation may be calculated for three or more consecutive readings, including readings that are separated by at least one full fluid volume turnover of the flow cell.

"Communication device" is used broadly herein to refer to a component or device that is capable of receiving and/or transmitting signals. Accordingly, a communication device can be a type of controller, a display, a computer or processer that receives signals, processes them, and sends commands, such as pump power command, valve control, sampling, collection, waste level action, and the like. The communication device can comprise a portable device or a work station, including that is being used by the operator to monitor the systems and, as appropriate, collect samples or over-ride the system.

"Operably connected" or "operatively coupled" refers to a configuration of elements, wherein an action or reaction of one element affects another element, but in a manner that preserves each element's functionality. For example, any of the controllers provided herein may be described as being operatively coupled to another component whose signal is used to control at least a portion of the system, such as pump power, flow direction, sample collection, or a signal sent to, or received by, an operator or an electronic device used by an operator.

"Fluid communication" refers to components that are connected by fluid flow, but in a manner that does not affect either component's functionality. The connection may be direct, where a flow from an output of one component is provided as an input to another component. The connection may be indirect, where an intervening component is positioned between the components.

<FIG> are schematic overviews of a system for automation of low-flow groundwater fluid sampling. Low flow pump <NUM> pumps fluid <NUM>, such as groundwater that has entered and been collected in a well <NUM> as indicated by arrows <NUM>, to a flow cell <NUM>. The system optionally includes a separate flow sensor <NUM>. Well <NUM> may be a monitoring well for monitoring possible contamination of groundwater. The flow cell <NUM> is in fluid and electronic communication with the low flow pump <NUM>. In this manner, the measured parameters by the flow cell may be used to, in turn, control pump, thereby establishing a feedback control. The flow cell <NUM> may have one or more fluid quality sensors <NUM> for measuring one or more fluid parameters. The flow cell may have an inlet port <NUM> for delivering fluid to the flow cell and outlet port <NUM> for removal of fluid from the flow cell. Valves <NUM> may be used to control flow of fluid to either waste container <NUM> or to fluid sample container <NUM>, including a fluid sample container that is part of an autosampler <NUM> for automatically collecting samples for later pick up by an operator for transport to an off-site testing facility. A level sensor <NUM> may be positioned at a bottom surface <NUM> of the waste container <NUM> to provide an indication of the level of waste fluid <NUM> in the waste container. Any of the level sensors may use a pressure sensor to determine fluid height by P=ρgh (P is pressure, ρ is density, g is acceleration due to gravity, and h is fluid height). Furthermore, by measuring the change in the waste fluid level with time, the level sensor may itself be characterized as a flow sensor, where a plot of height versus time and the corresponding slope provides a measure of flow-rate, with adjustment to pump power made to maintain a relatively constant slope.

Communication device <NUM> is in wireless communication with many of the components, as illustrated by dashed arrows. As shown in <FIG> and <FIG>, communication device <NUM> may include a mobile device <NUM> and/or a telemetry system <NUM>. The arrows are two-ended to reflect that not only is data provided to the device, but the device may be used to control the system, including pump flow-rate, sensor status, and any other component of interest, including valve <NUM> direction.

With respect to the well <NUM>, a depth sensor <NUM> may be used to provide a measure of fluid depth in the well, thereby providing information about fluid drawdown level <NUM>. The depth sensor <NUM> may be a pressure sensor. Sensor <NUM> may be in wireless communication with device <NUM> and/or pump <NUM>, so that pump power or fluid flow-rate is adjusted so as to maintain an appropriate fluid depth, and maintain drawdown <NUM> at an acceptable level, or at least a constant level.

An "auto-calibrator" <NUM> may be incorporated into the system for automatically calibrating the sensors. The auto-calibrator may be provided as an adaptor that fluidically connects to the flow cell, such as via a controllable valve. One or more calibration solutions may be connected so that the calibration solution(s) are forced, including via a pump, into the cell and flushed out. The pumping force may be via the connected low flow pump or by a separate auto-calibrator pump. Waste solutions go to the waste bucket.

The flow cell <NUM> may be installed at an orientation angle that is not vertical (as shown in <FIG>) and/or that is not horizontal, to prevent bubbles from forming on the sensor head. In another example (not shown in <FIG>), the flow cell <NUM> may be installed at any orientation angle that is suitable for functioning according to design specifications in the system for automation of low-flow groundwater fluid sampling. The flow cell <NUM> has minimal volume within the cell, to allow for faster flow cell turnover and to minimize the volume of calibration solutions used, with an inlet port and an outlet port. The flow cell may be characterized as having an internal volume corresponding to the volume of liquid within the flow cell. The invention is compatible with a range of flow cell internal volumes, such as between <NUM> and <NUM>, between <NUM> and <NUM>, and any sub-ranges thereof, with a preference for volumes as low as possible to provide faster flow cell turnover and efficiently utilize calibration solutions for the sensors.

The waste container may comprise a bucket with a level sensor or pressure transducer at or near the bucket bottom. The waste container is configured to allow waste flow to drop into the bucket with minimal surface disruption for more accurate readings. The bucket may have a constant diameter so that the pressure transducer is reliably calibrated to send a warning as to the need to empty the container of waste fluid and/or to decrease the flow through or stop the pump to avoid overflow of waste fluid. A top cover may be connected to the container to prevent spillage.

<FIG> is a method <NUM> for collecting low flow fluid samples from groundwater. In an example, method <NUM> is implemented and/or performed, at least in part, using the systems shown and described with reference to <FIG>. Method <NUM> includes continuously pumping <NUM> a flow of groundwater fluid to a flow cell at a substantially constant flow-rate. Method <NUM> includes measuring <NUM> a fluid quality parameter time course with a fluid sensor in said flow cell. Method <NUM> includes identifying <NUM> a positive fluid quality stabilization status for the measured fluid quality parameter that reaches a steady-state value. Method <NUM> includes wirelessly transmitting <NUM> a signal to a communication device indicating a fluid sample is ready to be collected from said flow of groundwater fluid. In an example, method <NUM> includes manually collecting <NUM> the fluid sample.

In an example, method <NUM> includes collecting <NUM> waste fluid that exits said flow cell in a waste container, and monitoring <NUM> a waste fluid level with a level sensor connected to said waste container. In the example, method <NUM> optionally includes activating <NUM> an autosampler <NUM> to automatically collect fluid sample that exits said flow cell after the positive fluid quality stabilization status is identified <NUM>.

In an example, the step of continuously pumping <NUM> is implemented and/or performed, at least in part, by a low-flow pump fluidly connected or in fluid contact with a sample well. In the example, the sample well is configured to monitor <NUM> contamination of ground water, including oil or gas contamination, heavy metal contamination, solvent contamination, or contamination of a material from an industrial process.

Method <NUM> optionally further includes the step of auto-calibrating <NUM> the fluid sensor before the measuring <NUM> step to ensure proper functioning of sensors in the flow cell. In the example, the auto-calibrating <NUM> step includes flushing <NUM> the flow cell with clean water. The auto-calibrating <NUM> step also includes filling <NUM> the flow cell with a calibration solution. The auto-calibrating <NUM> step further includes measuring <NUM> a calibration fluid quality parameter with the fluid sensor to ensure the sensor is calibrated, including over a range of calibration concentrations, to ensure accurate sensor readings before introduction of fluid sample. The auto-calibrating <NUM> step further includes calculating <NUM> a new calibration coefficient for the fluid sensor. The auto-calibrating <NUM> step also includes storing <NUM>, in memory device(s), the new calibration coefficient for a subsequent fluid test measurement. The auto-calibrating <NUM> step further includes repeating <NUM> (e.g., iterating) through the auto-calibrating <NUM> step until all water quality parameters for all fluid sensors are calibrated.

In an example, the continuously pumping <NUM> step is automated or semi-automated by measuring <NUM> fluid flow through said flow cell and/or measuring <NUM> a fluid depth in a sample well. In the example, the measured <NUM> fluid flow and/or the measured <NUM> fluid depth generates <NUM> an output that is provided <NUM> as an input to the low flow pump to control pump power, thereby controlling <NUM> fluid flow in a feedback loop so as to maintain <NUM> a substantially constant flow-rate and/or fluid depth in the sample well.

In an example, method <NUM> is implemented and/or performed, at least in part, for simultaneous collection of low flow fluid samples from a plurality of wells with minimal active intervention by an operator.

<FIG> is a method <NUM> for monitoring groundwater according to an embodiment of the disclosure. <FIG> is a schematic illustration of a groundwater sampling system <NUM> according to another embodiment of the disclosure. In an example, method <NUM> is implemented and/or performed, at least in part, using the system <NUM> shown in <FIG>. <FIG> is state diagram of a control scheme <NUM> for groundwater sampling. <FIG> is a prophetic example of a fluid stabilization condition, as determined by a turbidity sensor. Initially, as the pump is engaged and liquid is pumped to the flow cell, there may be initially high turbidity, due to long-term build-up prior to testing. The sensor(s) can be used to evaluate when a type of steady-state is achieved, indicating the fluid sample is "clean", as determined by magnitude of deviation <NUM>, such as a standard deviation or maximum deviation from an average over a certain number of fluid sample measurements or time period <NUM>.

Referring to <FIG> and <FIG>, method <NUM> includes flowing <NUM>, by at least one pump <NUM>, groundwater <NUM> under test from a groundwater source (e.g., a monitoring well <NUM>) to at least one flow cell <NUM>. Pump(s) <NUM> include at least one pump controller <NUM>. Flow cell(s) <NUM> includes one or more fluid quality sensors <NUM>. Method <NUM> includes, for an output flow <NUM> of the groundwater <NUM> under test from the flow cell <NUM>: collecting <NUM> a fluid sample <NUM> of the groundwater <NUM> under test; or collecting <NUM> a waste fluid <NUM> in at least one waste container <NUM>. Waste container(s) <NUM> include level sensor(s) <NUM>. Method <NUM> includes controlling <NUM>, by a sampling controller <NUM>, a groundwater monitoring system <NUM> used, at least in part, for implementing and/or performing method <NUM>. Sampling controller <NUM> is communicatively coupled to pump controller(s) <NUM>, flow sensor(s) <NUM>, and sensors <NUM> (in waste container) and <NUM> (in well <NUM>).

In method <NUM>, the controlling <NUM> step includes receiving <NUM> signals <NUM> from pump controller(s) <NUM>, fluid quality sensor(s) <NUM>, and sensors <NUM> and <NUM>. The controlling step <NUM> also includes regulating <NUM>, based on the received signals <NUM>, a flow-rate <NUM> to provide a desired or constant flow-rate to the flow cell <NUM>. The controlling step <NUM> further includes determining <NUM>, based on the received signals <NUM>, one or more fluid parameters over a time course. The controlling step <NUM> also includes determining <NUM>, based on the determined fluid parameter(s), a fluid stabilization status of groundwater <NUM> flowed to the flow cell <NUM> from the pump <NUM>. The controlling <NUM> step further includes, in response to a fluid stabilization condition being determined, initiating <NUM> collection (e.g., by the collecting <NUM> step) of at least one fluid sample <NUM>. In an example, method <NUM> is performed as a continuous or semi-continuous process, and the controlling <NUM> step is implemented for facilitating any or all of the aforementioned steps (e.g., flowing <NUM>, collecting <NUM>, and/or collecting <NUM> step(s)), and/or and any or all sub-steps thereof.

Referring to <FIG>, system <NUM> includes a pump <NUM>. In an example, pump <NUM> is a low flow pump <NUM>. Pump <NUM> includes a pump controller <NUM> for regulating a fluid flow-rate <NUM> from a monitoring well <NUM> through the pump <NUM>. In an example, pump <NUM> is positioned on a ground surface <NUM>, including proximal an opening <NUM> of monitoring well <NUM>. In another example (not shown in <FIG>), pump <NUM> is positioned in the well <NUM> below the ground surface <NUM>. System <NUM> includes a flow cell <NUM> in flow communication with the pump <NUM>, and a flow sensor <NUM>. In the example shown in <FIG>, flow sensor <NUM> is positioned upstream of an inlet <NUM> of flow cell <NUM>. In an example, flow sensor <NUM> is communicatively coupled to the pump controller <NUM> and/or a sampling controller <NUM>. Flow cell <NUM> also includes one or more fluid quality sensors <NUM>. Exemplary fluid quality sensor(s) <NUM> include one or more of: a turbidity sensor, a pressure sensor, a temperature sensor, a dissolved oxygen (DO) sensor, an electrical conductivity sensor, a pH sensor, an electrochemical sensor such as an oxidation reduction potential (ORP) sensor, and a fluorescence sensor. In an example, the flow cell <NUM> includes a plurality of fluid quality sensors <NUM> (e.g., first 450a, second 450b, and third 450c sensors). The sensor(s) <NUM> may be incorporated into a multi-parameter sonde <NUM>, with at least the active sensing surfaces of the multi-parameter sonde <NUM> positioned in the flow cell <NUM>. In an example, flow cell <NUM> includes an auto-calibrator <NUM> for automatically calibrating the fluid quality sensor(s) <NUM>. System <NUM> includes a waste container <NUM> in flow communication with the flow cell <NUM> for collecting a waste fluid <NUM>. In an example, waste container <NUM> is positioned on a ground pad <NUM>, which providers a stable and protective weight bearing platform for container <NUM>. Pump <NUM> and/or pump controller <NUM> may also be positioned on ground pad(s) <NUM> for similar purposes in system <NUM>. The waste container <NUM> includes a level sensor <NUM> for measuring a waste fluid depth <NUM> in the waste container <NUM>, including a pressure sensor to calculate fluid height in the container.

Referring to <FIG> and <FIG>, system <NUM> includes a sampling controller <NUM> communicatively coupled to pump controller <NUM>, flow sensor <NUM>, fluid quality sensor(s) <NUM>, and sensors <NUM> and <NUM>. In an example, system <NUM> includes a communication device <NUM> communicatively coupled to sampling controller <NUM>. In an example, communication device <NUM> includes a telemetry system <NUM> positioned for and configured to transmitting and/or receiving data (e.g., encoded in sensor signals <NUM> and/or system <NUM> control signals) to a mobile device <NUM> and/or a remote monitoring station <NUM>.

Sampling controller <NUM> implements a control scheme <NUM> for system <NUM> from a start state <NUM> (e.g., flow cell <NUM> awaiting flow of groundwater <NUM> under test to inlet <NUM> of flow cell <NUM>). In implementing control scheme <NUM>, sampling controller <NUM> receives <NUM> signals <NUM> from pump controller <NUM>, flow sensor <NUM>, fluid quality sensor(s) <NUM>, and level sensor <NUM>. In implementing control scheme <NUM>, sampling controller <NUM> transmits a control signal <NUM> to pump controller <NUM> to facilitate regulating <NUM> the fluid flow-rate <NUM> of groundwater <NUM> from the pump <NUM> to the flow cell <NUM> based on the received signals <NUM> to provide and maintain a desired or constant flow-rate <NUM> to the flow cell <NUM>. In an example, the desired or constant flow-rate <NUM> is greater than or equal to <NUM>/min and less than or equal to <NUM>/min (e.g., for a low flow pump <NUM>). In an example, sampling controller <NUM> regulates <NUM> flow-rate <NUM> by implementing, including, without limitation, in conjunction with pump controller <NUM>, proportional-integral (P. ) feedback control <NUM>.

In an example, flow-rate of groundwater <NUM> from pump <NUM> to flow cell <NUM> may be determined by sampling controller <NUM> based on the signal(s) <NUM> received from level <NUM> and/or depth <NUM> sensor(s) in the waste container <NUM>. For instance, for a waste container <NUM> having known dimensions, a time rate of change in waste fluid <NUM> level and/or depth determined by sampling controller <NUM> is used thereby to determine the flow-rate, either instead of, or in addition to, based on the signal(s) <NUM> received from flow sensor <NUM> and/or output flow sensor <NUM>.

For implementing control scheme <NUM> (<FIG>), sampling controller <NUM> determines <NUM> waste fluid depth <NUM> in waste container <NUM> based on received signals <NUM> from a pressure transducer <NUM>. In an example, sampling controller <NUM> provides <NUM> a waste fluid alarm <NUM> (e.g., including, without limitation, an audible and/or a visual alarm) in response to the measured waste fluid depth <NUM> in the waste container <NUM> being greater than or equal to a predetermined waste fluid depth <NUM> (e.g., excess waste). In an example (not shown in <FIG>), in response to the determined <NUM> waste fluid depth <NUM> being greater than or equal to the predetermined waste fluid depth <NUM>, sampling controller <NUM> transmits control signal <NUM> to pump controller <NUM> to facilitate stopping operation of pump(s) <NUM> or decreasing flow-rate <NUM>, thereby automatically preventing waste overflow and attendant rick of contamination.

For implementing control scheme <NUM>, sampling controller <NUM> determines <NUM> one or more fluid parameters over a time course based on the received signals <NUM>, including, without limitation, from fluid quality sensor(s) (<NUM>). In implementing control scheme <NUM>, sampling controller <NUM> determines <NUM> a fluid stabilization status of groundwater flowed to the flow cell <NUM> by the pump <NUM> based on the determined fluid parameter(s). In response to a fluid stabilization condition being determined <NUM> (e.g., fluid stabilization achieved), sampling controller <NUM> transmits a control signal <NUM> to flow cell <NUM> and/or to system <NUM> components associated with and/or connected to flow cell <NUM> to facilitate initiating <NUM> collection of at least one fluid sample <NUM> of the groundwater under test. In operation, all fluid (e.g., groundwater <NUM>) provided to flow cell <NUM> is either collected in the fluid sample(s) <NUM> or is directed to waste container <NUM> and collected therein as waste fluid <NUM>.

Referring to <FIG>, a plot <NUM> is a prophetic example of a fluid parameter (y-axis, e.g., turbidity of groundwater <NUM> under test) stabilizing over a time course (x-axis, e.g., hours). A turbidity data set <NUM> generally decreases over the time course, with measured turbidity values eventually dropping below a user-predetermined value <NUM>. In an example, for control scheme <NUM>, sampling controller <NUM> determines <NUM> that the fluid stabilization condition is achieved when both: a user-predetermined number (e.g., a number greater than <NUM>) of consecutive measured turbidity values in the data set <NUM> have values less than or equal to the predetermined value <NUM>; and those consecutive measured values have a standard deviation about a mean value of less than a user-predetermined standard deviation value <NUM> or a maximum deviation from an average value over a certain number of sample values obtained over a time interval <NUM>.

System <NUM> also includes a depth sensor <NUM> positioned in the monitoring well <NUM> (e.g., at least partially submerged under groundwater <NUM> surface <NUM>). Depth sensor <NUM> is communicatively coupled to the sampling controller <NUM>. In an example, for implementing control scheme <NUM>, sampling controller <NUM> assesses <NUM> a fluid draw-down level <NUM> in the monitoring well <NUM> based on one or more signals <NUM> received from the depth sensor <NUM>. In an example, sampling controller <NUM> provides <NUM> a draw-down alarm <NUM> in response to the assessed <NUM> drawdown level <NUM> in the monitoring well <NUM> being greater than or equal to a predetermined draw-down level <NUM> (e.g., excess draw down). In an example (not shown in <FIG>), in response to the assessed <NUM> draw-down level <NUM> being greater than or equal to the predetermined draw-down level <NUM>, sampling controller <NUM> transmits control signal <NUM> to pump controller <NUM> to facilitate stopping operation of pump(s) <NUM> or decreasing flow-rate <NUM>.

System <NUM> further includes a pressure transducer <NUM> positioned at or near (e.g., proximal) a bottom surface <NUM> inside of the waste container <NUM> for measuring a depth of waste fluid <NUM> in the container <NUM>. Pressure transducer <NUM> is communicatively coupled to the sampling controller <NUM>. In an example, for implementing control scheme <NUM>, sampling controller <NUM> determines <NUM> a waste fluid depth <NUM> in the waste container <NUM> based on one or more signals <NUM> received from the level sensor <NUM>. In an example, sampling controller <NUM> provides <NUM> waste fluid alarm <NUM> in response to the determined <NUM> waste fluid depth <NUM> in the waste container <NUM> being greater than or equal to a predetermined waste depth value <NUM> (e.g., excess level). In an example (not shown in <FIG>), in response to the determined <NUM> waste fluid depth <NUM> being greater than or equal to the predetermined waste depth <NUM>, sampling controller <NUM> transmits control signal <NUM> to pump controller <NUM> to facilitate stopping operation of pump(s) <NUM> or decreasing flow-rate <NUM>.

System <NUM> may include a first valve <NUM> having a first valve controller <NUM>. In an example, first valve <NUM> is a first solenoid valve <NUM>. First valve controller <NUM> is operatively coupled to first valve <NUM> and is communicatively coupled to sampling controller <NUM>. First valve <NUM> is positioned upstream of the inlet <NUM> of flow cell <NUM>. Under control of first valve controller <NUM>, first valve <NUM> enables flow <NUM> to be alternately directed to one or two flow paths: (A) to inlet <NUM> of flow cell <NUM>; and (B) to waste container <NUM>.

System <NUM> may include a second valve <NUM> having a second valve controller <NUM>. In an example, second valve <NUM> is a second solenoid valve <NUM>. Second valve controller <NUM> is operatively coupled to second valve and is communicatively coupled to sampling controller <NUM>. Second valve <NUM> is positioned downstream of an outlet <NUM> of flow cell <NUM>. Under control of second valve controller <NUM>, second valve <NUM> enables outlet flow <NUM> to be alternately directed to one or two flow paths: (C) to fluid sample collection <NUM>; and (D) to waste container <NUM>. Also, under control of second valve controller <NUM>, second valve <NUM> alternately opens and closes to facilitate alternately starting and stopping, respectively, flow of groundwater into or out of outlet <NUM>.

System <NUM> may further include an outlet flow sensor <NUM>. In the example shown in <FIG>, outlet flow sensor <NUM> is positioned downstream of outlet <NUM> of flow cell <NUM>. In the example, outlet flow sensor <NUM> is positioned proximal outlet <NUM> of flow cell <NUM>. Outlet flow sensor <NUM> is communicatively coupled to the sampling controller <NUM>. In an example, for implementing control scheme <NUM>, sampling controller <NUM> compares <NUM>, based on signals <NUM> received from flow sensor <NUM> and from outlet flow sensor <NUM>, a first flow-rate (e.g., flow-rate <NUM>) into the inlet <NUM> of flow cell <NUM> to a second flow-rate (e.g., flow-rate <NUM>) out of the outlet <NUM> of flow cell <NUM>. In an example, sampling controller <NUM> subtracts a measured value of flow-rate <NUM> from a measured value of flow-rate <NUM>. In the example, in response to a magnitude of a value of the difference between flow-rate <NUM> and flow-rate <NUM> being greater than or equal to a predetermined (e.g., predetermined by a system <NUM> user) flow-rate difference value (e.g., excess flow-rate difference), sampling controller <NUM> transmits <NUM> a control signal <NUM> to first valve controller <NUM> to facilitate diverting <NUM>, by first valve <NUM>, the pumped flow of the groundwater <NUM> under test from flow path A to flow path B. Diverting flow <NUM> from flow path A to flow path B bypasses <NUM> flow cell <NUM>. In an example, the value of the difference between flow-rate <NUM> and flow-rate <NUM> being greater than or equal to the predetermined flow-rate difference value is indicative of an operational problem in system <NUM> requiring attention by user(s) thereof, such as an obstruction to fluid flow in the flow cell <NUM>.

In an example, in response to the magnitude of the value of the difference between flow-rate <NUM> and flow-rate <NUM> being greater than or equal to the predetermined flow-rate difference value, sampling controller <NUM> transmits <NUM> a control signal <NUM> to second valve controller <NUM> to facilitate closing second valve <NUM> and ceasing flow <NUM> so that back flow (e.g., via flow path D) into the outlet <NUM> of flow cell <NUM> does not occur. In an example (not shown in <FIG>), in response to the magnitude of a value of the difference between flow-rate <NUM> and flow-rate <NUM> being greater than or equal to the predetermined flow-rate difference value, sampling controller <NUM> transmits <NUM> control signal <NUM> to pump controller <NUM> to facilitate stopping operation of pump(s) <NUM> or decreasing flow-rate <NUM>. In an example (not shown in <FIG>), in response to the magnitude of a value of the difference between flow-rate <NUM> and flow-rate <NUM> being greater than or equal to the predetermined flow-rate difference value, sampling controller <NUM> provides a flow-rate alarm (e.g., including, without limitation, an audible and/or a visual alarm).

For implementing control scheme <NUM>, initiating <NUM> collection of fluid sample(s) <NUM> includes, in response to the fluid stabilization condition being determined <NUM> (e.g., fluid stabilization achieved), sampling controller <NUM> transmits <NUM> a control signal <NUM> to second valve controller <NUM> to facilitate diverting <NUM>, by second valve <NUM>, the pumped flow (e.g., flow <NUM>) of groundwater <NUM> under test from flow path D to flow path C. This diverting <NUM> of flow <NUM> further facilitates the collecting <NUM> step of method <NUM>.

<FIG> is a schematic diagram of system <NUM> including an autosampler <NUM>. Referring to <FIG>, in an example, autosampler <NUM> includes an electric motor <NUM>. In an example, motor <NUM> is a stepper motor <NUM>. Autosampler <NUM> includes a motor controller <NUM> coupled to motor <NUM>. Motor controller <NUM> is communicatively coupled to sampling controller <NUM>. Autosampler <NUM> includes a sample platform <NUM> for holding a plurality of sample containers <NUM> (e.g., vials) for collecting and containing a plurality of fluid samples <NUM> (e.g., first 523a, second 523b,. , (n-<NUM>)-th, and (n)-th samples <NUM>), including, without limitation, over the time course. To increment sample collection between each of the plurality of containers <NUM>, motor <NUM> incrementally moves sample platform <NUM> (e.g., rotates in either a clockwise <NUM> or counterclockwise direction about a center axis <NUM> by a predetermined arc length <NUM>).

In an example, upon sampling controller <NUM> initiating <NUM> collection of fluid samples <NUM>, groundwater <NUM> under test enters a first container <NUM> via flow path C and is filled with first fluid sample 523a. Sampling controller <NUM> facilitates flow of first sample 523a into the first container <NUM> for a predetermined amount of time. Sampling controller <NUM> determines <NUM> the predetermined amount of time (e.g., sample flow time) based on the flow-rate <NUM>, the available volume of first container <NUM>, and the desired volume of first sample 523a to be collected. Substantially simultaneously with the start of the predetermined amount of time, sampling controller <NUM> facilitates, via second valve controller <NUM>, diverting <NUM> flow <NUM> from flow path D to flow path C, thereby enabling collection of first fluid sample 523a into the first container <NUM>. Substantially simultaneously with the conclusion of the predetermined amount of time, sampling controller <NUM> facilitates, via second valve controller <NUM>, diverting <NUM> flow <NUM> from flow path C to flow path D, thereby stopping collection of first fluid sample 523a into the first container <NUM>. Also, at or after the conclusion of the predetermined amount of time, sampling controller <NUM> facilitates, via motor controller <NUM> receiving a motor control signal <NUM> from controller <NUM>, rotating <NUM> the sample <NUM> by the predetermined arc length <NUM>. Sampling controller <NUM> iterates <NUM> through process steps associated with autosampler <NUM> for at least one iteration, based on the number (n) of fluid samples <NUM> to be collected.

In any or all of the examples described above with reference to system <NUM>, system <NUM> components that transmit and/or receive data (e.g., sensor signals <NUM> and/or system <NUM> control signals) may be wirelessly communicatively coupled to each other including, without limitation, using Bluetooth®, WiFi, Zigbee, and/or like wireless communication protocol(s) known to persons skilled in the art. In any or all of the examples described above with reference to system <NUM>, system <NUM> components that transmit and/or receive data (e.g., sensor signals <NUM> and/or system <NUM> control signals) may be communicatively coupled via wired connections including, without limitation, using serial, Ethernet, and/or like wired communication protocol(s) known to persons having skill in the art. In any or all of the examples described above with reference to system <NUM>, system <NUM> components that transmit and/or receive data (e.g., sensor signals <NUM> and/or system <NUM> control signals) may be communicatively coupled to each other using both of, or combinations of, wireless and wired communication protocols.

<FIG> is a schematic illustration of a networked computing environment for implementing the disclosed systems and methods for groundwater <NUM> sampling. In an example, system <NUM> includes at least one computing device <NUM> communicatively coupled to one or more deployments of system <NUM> (e.g., via telemetry system <NUM> of system <NUM> and a transceiver of computing device <NUM>, not shown in <FIG>) in one or more deployment locations <NUM> (e.g., first 815a, second 815b, and third 815c deployment locations) through a network <NUM> (e.g., the Internet, an intranet, and/or a cellular network). Telemetry system <NUM> and/or communication device <NUM> transmits and receives data (e.g., sensor signals <NUM> and/or system <NUM> control signals) to and from, respectively, the computing device (<NUM>). The computing device(s) include one or more of mobile device <NUM>, remote monitoring station <NUM>, a mobile smart phone <NUM>, and at least one server <NUM>.

In an example, system <NUM> is part of a multiplexed groundwater monitoring system <NUM>. Multiplexed system <NUM> includes a plurality of groundwater sampling systems <NUM> (e.g., first 400a, second 400b, and third 400c systems <NUM>) for simultaneously monitoring of a plurality of groundwater sources (e.g., monitoring wells <NUM>). Multiplexed system <NUM> may be implemented and/or deployed over a geographic area of any size, including, without limitation, utilizing Internet of Things (IoT) protocols, standards, and practices.

Computing device(s) <NUM> include one or more processors <NUM> communicatively coupled to one or more memory devices <NUM> (collectively referred to herein as memory <NUM>. Memory <NUM> stores including, without limitation, by reading, writing, and/or deleting, data associated with operation of system(s) <NUM>. In an example, memory <NUM> includes a non-transitory computer readable medium <NUM> which stores processor <NUM>-executable instructions encoded as software <NUM> or firmware. When executed by the processor(s), the processor <NUM>-executable instructions cause the processor(s) <NUM> to execute processor <NUM> and memory <NUM> operations that facilitate implementing the control scheme <NUM> in system(s) <NUM>, as shown and described above with reference to <FIG>. In examples of system <NUM> and/or system <NUM> where computing device <NUM> is a mobile smart phone <NUM>, memory <NUM> thereof includes an app <NUM>. In such embodiments, the app <NUM> includes the non-transitory computer readable medium <NUM>. In an example, computing device(s) <NUM> implement and/or perform, at least in part, the functionality of sampling controller(s) <NUM> in system(s) <NUM> and/or system <NUM>, either instead of, or in addition to, sampling controller(s) <NUM> resident at or near location(s) <NUM> of groundwater <NUM> source(s) (e.g., monitoring well(s) <NUM>).

In an example, system(s) <NUM> and/or multiplexed system <NUM> is/are used in a groundwater <NUM> contamination monitoring and/or remediation application(s). In such embodiments, collected (e.g., in the collecting <NUM> step of method <NUM>) fluid sample(s) <NUM> is/are used for off-site testing of the fluid sample(s) <NUM>. In an example, system(s) <NUM> and/or multiplexed system <NUM> is/are used for monitoring and/or remediation application(s) for oil, gas, and/or chemical facilities and/or sources of actual or potential groundwater <NUM> contamination. In such embodiments, where the above described components of system <NUM> are positioned in proximity to flammable materials and/or chemicals, such component(s) are selected and/or installed in accordance with "explosion proof" standards so as to comply with application construction codes and/or related laws and regulations.

All references throughout this application, for example patent documents including issued or granted patents or equivalents; patent application publications; and non-patent literature documents or other source material; are hereby incorporated by reference herein in their entireties, as though individually incorporated by reference, to the extent each reference is at least partially not inconsistent with the disclosure in this application (for example, a reference that is partially inconsistent is incorporated by reference except for the partially inconsistent portion of the reference).

The terms and expressions which have been employed herein are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the invention claimed. Thus, it should be understood that although the present invention has been specifically disclosed by preferred embodiments, exemplary embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this invention as defined by the appended claims. The specific embodiments provided herein are examples of useful embodiments of the present invention and it will be apparent to one skilled in the art that the present invention may be carried out using a large number of variations of the devices, device components, methods steps set forth in the present description. As will be obvious to one of skill in the art, methods and devices useful for the present methods can include a large number of optional composition and processing elements and steps.

When a group of substituents is disclosed herein, it is understood that all individual members of that group and all subgroups, are disclosed separately. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and subcombinations possible of the group are intended to be individually included in the disclosure.

Every formulation or combination of components described or exemplified herein can be used to practice the invention, unless otherwise stated.

Whenever a range is given in the specification, for example, a temperature range, a flow range, a number range, a time range, or a composition or concentration range, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. It will be understood that any subranges or individual values in a range or subrange that are included in the description herein can be excluded from the claims herein.

All patents and publications mentioned in the specification are indicative of the levels of skill of those skilled in the art to which the invention pertains. References cited herein are incorporated by reference herein in their entirety to indicate the state of the art as of their publication or filing date and it is intended that this information can be employed herein, if needed, to exclude specific embodiments that are in the prior art.

As used herein, "comprising" is synonymous with "including," "containing," or "characterized by," and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps. As used herein, "consisting of" excludes any element, step, or ingredient not specified in the claim element. As used herein, "consisting essentially of" does not exclude materials or steps that do not materially affect the basic and novel characteristics of the claim. In each instance herein any of the terms "comprising", "consisting essentially of" and "consisting of" may be replaced with either of the other two terms. The invention illustratively described herein suitably may be practiced in the absence of any element or elements, limitation or limitations which is not specifically disclosed herein.

Claim 1:
A low flow groundwater fluid sampling system comprising:
a low flow pump (<NUM>);
a flow cell (<NUM>) in fluid communication with said low flow pump, wherein said flow cell comprises one or more fluid quality sensors (<NUM>);
a waste container (<NUM>) in fluid communication with said flow cell for collecting a waste fluid (<NUM>), wherein said waste container comprises a level sensor (<NUM>) for measuring a waste fluid depth in said waste container;
a communication device (<NUM>, <NUM>, <NUM>) in wireless communication with each of said low flow pump, flow cell and waste container, wherein:
said low flow pump has an adjustable pump power to provide a desired constant flow-rate to said flow cell from an electronic communication between said low flow pump and said level sensor, and said at least one fluid quality sensor measures one or more fluid parameters over a time course to assess a fluid stabilization status;
upon fluid stabilization said communication device indicates an affirmative fluid stabilization condition and that a fluid sample may be collected; and
a valve (<NUM>) to control flow of fluid to either said waste container (<NUM>) or to a fluid sample container (<NUM>) so that all fluid provided to said flow cell by said low flow pump is either collected in said fluid sample or directed to said waste container and collected as said waste fluid.