Methods and systems for sensing a material in a fluid

Abstract

Methods and systems for sensing a target material in a fluid, including methods and systems that can be repeated while avoiding or reducing the need to recalibrate a sensor configured to detect the target material. The target material may be nitrous oxide (N2O) in wastewater.

Description

METHODS AND SYSTEMS FOR SENSING A MATERIAL IN A FLUIDCross-reference to Related Applications

[0001] This application claims priority to Finnish Patent Application No. 20245991, filed August 8, 2024, and U.S. Provisional Patent Application No. 63 / 631,220, filed April 8, 2024, which are incorporated by reference herein.Field of the Disclosure

[0002] This disclosure relates to methods and systems for sensing a material, such as N2O, in a fluid, such as wastewater.Background

[0003] Nitrous oxide (N2O) is a greenhouse gas that can trap 300 times more heat in the atmosphere than carbon dioxide, according to some studies.

[0004] N2O is present in the atmosphere due, for example, to the microbial degradation of organic compounds. Microbial degradation is commonly used in the treatment of wastewater. Wastewater treatment typically includes two processes for removing nitrogen: nitrification and denitrification, and both of these processes can produce N2O. A number of factors can impact whether and / or how much N2O is produced during wastewater treatment processes, and attempts have been made to control and / or reduce N2O emissions by controlling or optimizing any one or more of these factors. In any effort to control and / or reduce N2O emissions, accurately and repeatedly measuring concentrations of N2O can be an important element. Sensors, however, can require frequent recalibration, especially if the tested samples are at different temperatures.

[0005] There remains a need for systems and methods for accurately and / or repeatedly (e.g., continuously) determining concentrations of N2O, including methods and systems that avoid the recalibration of sensors or reduce the number of times a sensor must be recalibrated.Brief Summary

[0006] Provided herein are methods and systems for sensing a target material, such as N2O, in a fluid. In some embodiments, concentrations of N2O can be measured more than once (for example, continuously) without requiring the recalibration of a sensor between measurements or at inconvenient intervals. In some embodiments, the systems and methods152732480 1collect and measure samples from more than one sampling point, such as two, three, four, or more sampling points. The methods and systems described herein may contribute to a reduction in N2O greenhouse gas emissions.

[0007] In one aspect, methods of sensing are provided. In some embodiments, the methods include providing a fluid in a reservoir, wherein the fluid includes water and a target material, such as N2O; collecting from the reservoir a first sample of the fluid, wherein the first sample is at a first temperature; modifying the first temperature of the first sample to a first modified temperature, wherein the first modified temperature is within a predetermined range of deviation from a calibration temperature of a sensor; and determining with the sensor a first concentration of the target material, such as N2O, in the first sample. The methods also may include collecting from the reservoir a second sample of the fluid, wherein the second sample is at a second temperature; modifying the second temperature of the second sample to a second modified temperature within a predetermined range of deviation from the calibration temperature of a sensor; and determining with the sensor a second concentration of the target material, such as N2O, in the second sample. These steps may be repeated one or more times (e.g., continuously), as described herein.

[0008] In another aspect, systems for sensing are provided. In some embodiments, the systems include a sensor, a temperature modifying apparatus, a sample channel that includes a sample input, a cleaning liquid channel that includes a cleaning liquid input, one or more pumps, one or more pressurized lines, or a combination thereof. The one or more pumps and / or one or more pressurized lines may be configured to transport a sample from the sample input to the temperature modifying apparatus, and then to the sensor. The one or more pumps and / or one or more pressurized lines may be configured to transport a cleaning liquid from the cleaning liquid input to the sensor. The one or more pumps and / or one or more pressurized lines may be configured to transport the sample from the sensor to a reservoir from which the sample was collected. The systems may include at least one controller, which may be configured to operate and / or receive data from a sensor, a temperature modifying apparatus, one or more pumps, one or more pressurized lines, an apparatus configured to dispose a remediation agent in a reservoir, or a combination thereof. In some embodiments, the systems include a housing, wherein a sensor, a temperature modify ing apparatus, a sample channel, a cleaning liquid channel, or a combination thereof is / are at least partially arranged in or on the housing.

[0009] Additional aspects will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the aspects252732480 1described herein. The advantages described herein may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.Brief Description of the Drawings

[0010] FIG. 1 is a schematic of an embodiment of a system.

[0011] FIG. 2 is a schematic of an embodiment of a system that includes four sample inputs.Detailed Description

[0012] Provided herein are methods and systems for sensing a target material, such as N2O, in a fluid, such as wastewater.

[0013] Methods

[0014] In some embodiments, the methods include providing a fluid in a reservoir. The fluid in the reservoir may include water and a target material, such as N2O. As used herein, the phrase ‘'target material” refers to a material that is detectable by a sensor of the methods and systems provided herein. The target material may include N2O or any other material that is detectable by known sensors.

[0015] In some embodiments, the methods herein include collecting from the reservoir a first sample of the fluid. The first sample may be at a first temperature. The first temperature may differ, to an undesirable extent, from the calibration temperature of the sensor. Therefore, the methods may include modifying the first temperature of the first sample to a first modified temperature, wherein the first modified temperature is within a predetermined range of deviation from a calibration temperature of a sensor. The sensor, as a result, may not require frequent and inconvenient recalibration. The methods also may include determining with the sensor a first concentration of the target material, such as N2O, in the first sample.

[0016] The methods provided herein, or elements thereof, may be repeated any number of times. In some embodiments, the methods include collecting from the reservoir a second sample of the fluid, wherein the second sample is at a second temperature; modifying the second temperature of the second sample to a second modified temperature within a predetermined range of deviation from the calibration temperature of a sensor; and determining with the sensor a second concentration of the target material, such as N2O, in the352732480 1second sample. The collecting, modifying, and / or determining elements of the methods may be repeated one or more times. In some embodiments, the methods provided herein, or elements thereof, are performed continuously.

[0017] The methods provided herein may include calibrating and / or maintaining the sensor in any manner. In some embodiments, the methods include calibrating the sensor to a calibration temperature before the determining of the first concentration of the target material, such as N2O. in the first sample. In some embodiments, the methods include contacting the sensor with a cleaning liquid. The sensor may be contacted with a cleaning liquid after the determining of the first concentration, and before the determining of the second concentration.

[0018] The methods provided herein may allow a user to determine whether a concentration of a target material in a fluid of a reservoir is increasing or decreasing. In some embodiments, the methods include comparing the first concentration of the target material, such as N2O, and the second concentration of the target material, such as N2O, to determine whether the first concentration is greater than or less than the second concentration. When the methods herein are repeated, the methods also may include comparing any two of the concentrations of the target material, such as N2O, to determine whether the concentration of the target material, such as N2O, in the fluid is increasing or decreasing.

[0019] If a concentration of a target material is increasing or decreasing, a remediating action may be implemented or modified accordingly. In some embodiments, the methods include disposing in the reservoir an amount of a remediation agent, which is configured to reduce the concentration of the target material, such as N2O, in the reservoir. The amount of the remediation agent that is disposed in the reservoir may be determined based on the first concentration, the second concentration, the comparing of the first concentration and the second concentration, or the comparing of any two of the second concentrations. As used herein, the phrase ‘’remediation agent” refers to an agent that changes, in any manner, a concentration of a target material, such as N2O, in a fluid in a reservoir. The remediation agent may include carbon, a carbon source, a pH modifier, or a combination thereof.

[0020] Systems

[0021] Also provided herein are systems for sensing a target material in a fluid. In some embodiments, the systems include a sensor, a temperature modify ing apparatus, a sample channel that includes a sample input, a cleaning liquid channel that includes a cleaning liquid input, one or more pumps, one or more pressurized lines, or a combination452732480 1thereof. The systems generally may include any number of sample inputs, such as one to ten, one to eight, one to six, or one to four sample inputs. When more than one sample input is present, each sample input may be configured to collect or receive samples from the same or different measuring points, such as measuring points at different wastewater treatment process zones. The different wastewater treatment process zones may include predenitrification, nitrification, post-denitrification, etc. The samples may be measured in any order, such as alternately or in another programmed order, and under any schedule, for example, measurements may be performed once per a specified time period, such as one per hour.

[0022] A pump and / or pressurized line may be configured to transport a sample from a sample input to a temperature modifying apparatus, and then to a sensor. A sample may be transported, at least in part, by a pressurized line. Additionally or alternatively, a pump and / or pressurized line may be configured to transport a cleaning liquid from a cleaning liquid input to a sensor. A pump and / or pressurized line also may be configured to transport a sample from the sensor to a reservoir from which the sample was collected. These actions may be performed by one pump, two or more pumps, one pressurized line, two or more pressurized lines, or any combination thereof.

[0023] In some embodiments, a sample channel and a cleaning liquid channel merge to form a single channel, and optionally diverge from the single channel. The merging of the channels may improve the ability to clean the channels of sample, clean the sensor, or a combination thereof. In some embodiments, a sample channel and a cleaning liquid channel merge to form a single channel (i) upstream of a temperature modifying apparatus, or (ii) downstream of a temperature modifying apparatus and upstream of a sensor. In some embodiments, a sample channel and a cleaning liquid channel may diverge from the single channel (i) upstream of a temperature modifying apparatus, or (ii) downstream of a temperature modifying apparatus and upstream of a sensor.

[0024] An embodiment of a system is depicted at FIG. 1. FIG. 1 is a schematic of an embodiment of a system 100 that includes a sensor 110 that is in communication with a device 111 configured for measuring an electrical current. The system 100 also includes a temperature modifying apparatus 120, a sample channel 130 that includes a sample input 131, and a cleaning liquid channel 140 that includes a cleaning liquid input 141. The system 100 also includes valves 132 and 142, which may be used to control flows within the sample channel 130 and the cleaning liquid channel 140, respectively. The system 100 of FIG. 1 also includes a pump 150 that is configured to transport a sample from the sample input 131552732480 1to the temperature modifying apparatus 120, and then to the sensor 110. The pump 150 also is configured to transport a cleaning liquid from the cleaning liquid input 141 to the sensor 110. Although not s own at FIG. 1, the pump 150 may return a sample to a reservoir, such as the reservoir from w hich the sample was collected. The sensor 100 of FIG. 1 also includes a housing 160, and the sample channel 130 and the cleaning liquid channel 140 merge to form a single channel 170 upstream of the temperature modifying apparatus 120. The housing 160 also includes wheels 161 to improve the mobility of the system 100.

[0025] An embodiment of a system is depicted at FIG. 2. FIG. 2 is a schematic of an embodiment of a system 200 that includes a sensor 110 that is in communication with a device 111 configured for measuring an electrical current. The system 200 also includes a temperature modifying apparatus 120. a cleaning liquid channel 140 that includes a cleaning liquid input 141, and four sample channels (130a, 130b, 130c, 130d) that correspond to four sample inputs (131a, 131b, 131c, Old). The sample inputs (131a, 131b, 131c, Old) may allow samples from different locations or zones of a w astew ater treatment process to be assessed by the system 200. The system 200 also includes valves (132a, 132b. 132c, 132d, 142), w hich may be used to control flow s within the sample channels (130a, 130b, 130c, OOd) and the cleaning liquid channel 140, respectively. The system 200 of FIG. 2 also includes a pump 150 that is configured to transport a sample from the sample inputs (131a, 131b, 131c, 131d) to the temperature modifying apparatus 120. and then to the sensor 110. The pump 150 also is configured to transport a cleaning liquid from the cleaning liquid input 141 to the sensor 110. Although not shown at FIG. 2, the pump 150 may return a sample to a reservoir, such as the resen oi r from which the sample w as collected. The sensor 200 of FIG. 2 also includes a housing 160, and the sample channels (131a, 131b, 131c, 131d) and the cleaning liquid channel 140 merge to form a single channel 170 upstream of the temperature modifying apparatus 120. The housing 160 also includes wheels 161 to improve the mobility of the system 100. Although not shown, the system 200 of FIG. 2 may be a component of a multi-component system for treating w astew ater, wherein the other components of the multicomponent system may include the apparatuses and systems described in U.S. Patent Application Publication No. 2023 / 0192517.

[0026] The systems provided herein also may include an apparatus, such as a pump, that is configured to dispose a remediation agent in the reservoir.

[0027] In some embodiments, the systems also include at least one controller. The at least one controller may be configured to operate and / or receive data from any component(s) of the systems, such as a sensor, a temperature modifying apparatus, a pump, a pressurized652732480 1line, an apparatus configured to dispose a remediation agent in the reservoir, or a combination thereof.

[0028] Any one or more of the components of the systems provided herein may be at least partially arranged in or on a housing. For example, a sensor, a temperature modifying apparatus, a sample channel, a cleaning liquid channel, or a combination thereof is / are at least partially arranged in or on the housing. In some embodiments, one or more pumps is / are at least partially arranged in or on the housing.

[0029] Collecting Samples

[0030] The methods provided herein may include collecting samples of a fluid from a reservoir. The samples may include a single portion of the fluid or two or more portions of the fluid. When the samples include two or more portions, each of the two or more portions may be collected from (i) a different location of a reservoir, (ii) different reservoirs, or (iii) a combination thereof. In some embodiments, the collecting of a first sample of a fluid and / or a second sample of a fluid includes collecting from a reservoir two or more portions of a fluid, wherein each of the two or more portions is collected from a different location of a reservoir, and combining the two or more portions of the fluid to form the first sample and / or the second sample of the fluid.

[0031] The two or more portions may include any number of portions (e.g., tw o, three, four, five, six, seven, eight, or more), such as a number of portions effective to neutralize, to a desirable extent, inaccuracies that may be caused by a concentration gradient of a target material in a fluid. For example, the number of portions may be effective to prevent a concentration gradient of a target material, such as N2O, in a fluid from disrupting (e.g., by more than 1 %, more than 5 %, more than 10 %, more than 15 %, or more than 20 %) a correlation between (i) a first concentration and / or a second concentration of a target material, such as N2O, and (ii) a concentration of a target material, such as N2O, in a fluid in the reservoir. For example, if the concentration of the target material in the fluid of the reserv oir is X, and a concentration gradient of the target material is present in the fluid, then the concentration gradient does not disrupt the correlation between the first concentration and the concentration of the target material by 5 % or more if the first concentration is from about 0.95X to about 1.05X.

[0032] When two or more portions of a fluid are collected from different locations of a reservoir, the different locations may be at different vertical distances from the lowest point of the reservoir. Other locations, however, are envisioned, and the selections of the locations752732480 1may be determined by one or more factors, such as the character of the reservoir, a mixing apparatus used to mix the fluid, etc.

[0033] In some embodiments, the samples are collected from for or more sampling points. One or more of the sampling points can be present in any wastewater process zones, including pre-denitrification, nitrification, post-denitrification, etc. One of more of the sampling points may be present in an anoxic zone, and one or more of the sampling points may be present in an aerobic zone.

[0034] Modifying the Temperatures

[0035] A temperature of a sample may be greater than, equal to, or less than a calibration temperature of a sensor. Therefore, the temperature of a sample may be increased or decreased in the methods provided herein. When the modifying of a temperature of a sample includes increasing the temperature of the sample, then a temperature modifying apparatus may be a heating apparatus. Conversely, when the modifying of a temperature of a sample includes decreasing a temperature of the sample, the temperature modifying apparatus may be a cooling apparatus. A temperature modifying apparatus, therefore, may include a heating apparatus, a cooling apparatus, or a combination thereof.

[0036] The heating apparatus may include any known heating apparatus. In some embodiments, the heating apparatus includes a heating mantel. The heating mantel may be an electrical heating mantel. The heating apparatus, such as a heating mantel, may include a sensor, which may provide a signal to one or more components when a desired temperature is reached. Any known sensor may be used, but, in some embodiments, the sensor includes a resistance thermometer, such as a PtlOO temperature sensor.

[0037] Calibration Temperatures

[0038] A sensor generally may be calibrated at any temperature. In some embodiments, the calibration temperature is about 5 °C to about 40°C, about 15 °C to about 30 °C, about 20 °C to about 30 °C, or about 20 °C to about 25 °C.

[0039] Any predetermined range of deviation from the calibration temperature may be selected for the methods and systems provided herein. The range of deviation may be selected based on the extent of deviation that can be tolerated by a sensor without requiring recalibration and / or interfering with the accuracy of the sensor. In some embodiments, the range of deviation from the calibration temperature is plus or minus about 10 °C, plus or minus about 9 °C, plus or minus about 8 °C. plus or minus about 7 °C, plus or minus about 6 °C. plus or minus about 5 °C, plus or minus about 4 °C. plus or minus about 3 °C, plus or minus about 2 °C, or plus or minus about 1 °C of the calibration temperature of the sensor.852732480 1

[0040] Not wishing to be bound by any particular theory, it is believed that the modifying of the temperatures of the samples, as described herein, may reduce the frequency at which the sensor is (i) calibrated, (ii) subjected to maintenance, or (iii) a combination thereof.

[0041] Reservoirs and Fluids

[0042] Any fluid may be subjected to the methods provided herein. In some embodiments, the fluid is an aqueous fluid, such as wastewater. The wastewater may include any agent used in the treatment of wastewater. For example, the wastewater may include one or more microbial species, such as microbial species used in nitrogen removal processes, such as nitrification and denitrification. Nitrification and denitrification may produce a target material, such as N2O. In some embodiments, the methods or systems described herein are used to measure N2O formation and emissions from one or more measuring points, such as up to four measuring points. The measuring points may be selected from wastewater treatment process zones, such as pre-denitrification, nitrification, and post-denitrification. In some embodiments, the measuring point is selected from the nitrification process zone. Not wishing to be bound by any particular theory, it is believed that a majority of N2O may be formed during nitrification.

[0043] The reservoir may include any reservoir that is capable of retaining a fluid. In some embodiments, the reservoir is a tank, such as a tank used in wastewater treatment. The reservoir may include an aeration tank. The reservoir may be configured to provide one or more needed conditions, such as the conditions used in the treatment of wastewater. For example, the fluid in the reservoir may be under aerobic conditions, which may be suitable for nitrification. As a further example, the fluid in the reservoir may be under anoxic conditions, which may be suitable for denitrification. As used herein, the phrase “anoxic conditions’’ refers to an environment that contains little (100 ppm or less, or 10 ppm or less) or no dissolved oxygen.

[0044] The systems described herein may be used in biological wastewater treatment processes, including those with nitrogen removal processes containing either nitrification and denitrification, or only nitrification. The biological wastewater treatment processes may be municipal or industrial.

[0045] Sensors

[0046] The systems and methods provided herein may include or use, respectively, any known sensor.952732480 1

[0047] In some embodiments, the sensor includes a cathode, such as a metal cathode. The sensor may be in communication with a device for measuring electrical current, such as a picoammeter. The sensor may be configured to reduce the target material, such as N2O, at a cathode surface to produce an electrical current, and the device for measuring electrical current may convert the electrical current to a signal.

[0048] All referenced publications are incorporated herein by reference in their entirety. Furthermore, where a definition or use of a term in a reference, which is incorporated by reference herein, is inconsistent or contrary to the definition of that term provided herein, the definition of that term provided herein applies and the definition of that term in the reference does not apply.

[0049] While certain aspects of conventional technologies have been discussed to facilitate disclosure of various embodiments, applicants in no way disclaim these technical aspects, and it is contemplated that the present disclosure may encompass one or more of the conventional technical aspects discussed herein.

[0050] The present disclosure may address one or more of the problems and deficiencies of known methods and processes. However, it is contemplated that various embodiments may prove useful in addressing other problems and deficiencies in a number of technical areas. Therefore, the present disclosure should not necessarily be construed as limited to addressing any of the particular problems or deficiencies discussed herein.

[0051] In this specification, where a document, act or item of knowledge is referred to or discussed, this reference or discussion is not an admission that the document, act or item of knowledge or any combination thereof was at the priority date, publicly available, know n to the public, part of common general knowledge, or otherwise constitutes prior art under the applicable statutory provisions; or is known to be relevant to an attempt to solve any problem with which this specification is concerned.

[0052] In the descriptions provided herein, the terms “includes,” “is,” “containing,” “having,” and “comprises” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” When systems or methods are claimed or described in terms of “comprising” various steps or components, the systems or methods can also “consist essentially of’ or “consist of’ the various steps or components, unless stated otherwise.

[0053] The terms “a,” “an,” and “the” are intended to include plural alternatives, e.g., at least one. For instance, the disclosure of “a fluid”, “a reservoir”, and the like, is meant to1052732480 1encompass one, or mixtures or combinations of more than one fluid, reservoir, and the like, unless otherwise specified.

[0054] Various numerical ranges may be disclosed herein. When Applicant discloses or claims a range of any type, Applicant’s intent is to disclose or claim individually each possible number that such a range could reasonably encompass, including end points of the range as well as any sub-ranges and combinations of sub-ranges encompassed therein, unless otherwise specified. Moreover, all numerical end points of ranges disclosed herein are approximate. As a representative example, Applicant discloses, in some embodiments, that the calibration temperature is about 20 °C to about 30 °C. This range should be interpreted as encompassing about 20 °C and about 30 °C. and further encompasses “about” each of 21 °C, 22 °C, 23 °C, 24 °C, 25 °C, 26 °C. 27 °C, 28 °C, and 29 °C, including any ranges and subranges between any of these values.

[0055] As used herein, the term “about” means plus or minus 10 % of the numerical value of the number with which it is being used.

[0056] EXAMPLES

[0057] The present disclosure is further illustrated by the following examples, which are not to be construed in any way as imposing limitations upon the scope thereof. On the contrary, it is to be clearly understood that resort may be had to various other aspects, embodiments, modifications, and equivalents thereof which, after reading the description herein, may suggest themselves to one of ordinary skill in the art without departing from the spirit of the present disclosure or the scope of the appended claims. Thus, other aspects of this disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein.

[0058] Example 1 - Measuring N2O Formation

[0059] In this example, an embodiment of a system described herein was used to measure N2O formation and emissions from wastewater at one to four measuring points. The one to four measuring points coincided with one or more wastewater treatment process zones, such as pre-denitrification, nitrification, and post-denitrification.

[0060] The system of this example was installed, and sample channels were arranged to transfer samples from various sampling points to the system. In this example, four separate sampling points were used, but other numbers of sampling points may be used.

[0061] The embodiment of the system used in this example included a sensor, a temperature modifying apparatus, a sample channel that included a sample input, a cleaning1152732480 1liquid channel that included a cleaning liquid input, a pump, and a cabinet in which the pump was placed. The system of this example also included a control cabinet and a measurement cabinet in which the instruments and mechanical valves were placed. The sample channel of this example included four individual sample lines, which were used to transferred samples from the wastewater treatment process with the pump. Although pressurized lines were not used in this example, their use is envisioned.

[0062] The sensor of the system of this example included a control box, where sensor data was processed and read to other components of the system. The sensor of the system of this example was a UNISENSE® N2O wastewater system sensor, which included a sensor tip, a sensor body, and a control box. The sensor head was a Clark-ty pe sensor with an internal reference, a cathode, a guard cathode, and a front oxygen trap with a reducing medium. The operating temperature of the sensor was from 0-27 °C, and the standard (SR) tip or medium (MR) tip of the sensor could be used. The tip affected the measuring range of the unit. The SR tip measurement range in this example was 0-1.5 mg N2O - N / L, and the MR tip had a measurement range of 0-9 mg N2O - N / L. The measurement of the sensor of this example was achieved when N2O entered the sensor through a silicone rubber membrane, and was reduced to N2, which generated an electrical current. The resulting signal was sent to the controller for processing.

[0063] The sensor of this example was calibrated with a two point calibrated at a targeted temperature. The zero point was measured in tap water (4 L) in a thermostat bucket, and then the stabilized sensor value was logged into the system of this example. 5 mL of calibration liquid was added to the tap water with a syringe under the liquid level. When the value was stabilized, the calibration concentration was added to the system. The water temperatures at both calibration points were logged onto the control screen.

[0064] The system of this example also included software featuring three loops: washing, sampling, and measuring. The washing loop facilitated the washing of the sample lines and measurement chamber. The sampling loop facilitated the transfer of the samples into the measurement chamber. The measuring loop facilitated the heating of the sample, and the logging of the measured value into memory.

[0065] During the wastewater treatment process, the system measured N2O values of the samples, and, as needed, the samples were heated, as described herein, before the measurements were performed. The system of this example included a measurement chamber featuring an additional PtlOO sensor, which was configured to achieve safe heating1252732480 1of the sample. The samples of this example were heated with a heating mantel installed in the measurement chamber.

[0066] After the samples were pumped into the measuring chamber, where the sensor was located in this example, the sample w as heated. The heating was achieved with an electrical mantel that w as arranged outside of the measurement chamber. The mantel w as controlled via a PtlOO sensor, which provided a signal to the software when the desired temperature was reached. This configuration allowed the desired setpoint temperature to be adjusted to a temperature betw een 0-27 °C.

[0067] The unit returned the measured sample back to the treatment process, and performed a washing cycle for the unit and lines before commencing the next measuring sequence.

[0068] Example 2 - Detection ofN O

[0069] In this example, tests were performed to compare different measurement points collected by a localized sensor and sampling lines of an embodiment of a system described herein. From two separate trains, the samples were taken, and the results compared those obtained from the heated sample and the local sensor.

[0070] The data collected was used to calculate an R2value, which showed the square of the correlation. The results demonstrated a large positive correlation, because the values of R2were greater than 0.7 (first train; y = 0.8837x - 0.0061; R2= 0.766) (second train; y = 0.8131X - 0.0226, R2= 0.8313).

[0071] EMBODIMENTS

[0072] The following is a non-limiting listing of embodiments of the disclosure.

[0073] Methods

[0074] Embodiment 1. A method of sensing, the method comprising, consisting essentially of, or consisting of -

[0075] providing a fluid in a reservoir, wherein the fluid comprises water and a target material, such as N2O;

[0076] collecting from the reservoir a first sample of the fluid, wherein the first sample is at a first temperature;

[0077] modifying the first temperature of the first sample to a first modified temperature, wherein the first modified temperature is within a predetermined range of deviation from a calibration temperature of a sensor; and1352732480 1

[0078] determining w ith the sensor a first concentration of the target material, such as N2O, in the first sample.

[0079] Embodiment 2. The method of Embodiment 1, further comprising, consisting essentially of, or consisting of -

[0080] (i) collecting from the reservoir a second sample of the fluid, wherein the second sample is at a second temperature;

[0081] (ii) modifying the second temperature of the second sample to a second modified temperature within the predetermined range of deviation from the calibration temperature of the sensor; and

[0082] (iii) determining with the sensor a second concentration of the target material, such as N2O. in the second sample.

[0083] Embodiment 3. The method of Embodiment 2, further comprising, consisting essentially of, or consisting of repeating steps (i), (ii), and (iii) one or more times (e.g., continuously).

[0084] Embodiment 4. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of contacting the sensor with a cleaning liquid, such as after the determining of the first concentration, and before the determining of the second concentration, and / or after the determining of the second concentration.

[0085] Embodiment 5. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of comparing the first concentration of the target material, such as N2O, and the second concentration of the target material, such as N2O, to determine whether the first concentration is greater than or less than the second concentration.

[0086] Embodiment 6. The method of any of the preceding Embodiments, wherein when steps (i), (ii), and (iii) are repeated one or more times, the method further comprises, consists essentially of, or consists of comparing any two of the second concentrations of the target material, such as N2O, to determine whether the concentration of the target material, such as N2O, in the fluid is increasing or decreasing.

[0087] Embodiment 7. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of calibrating the sensor to the calibration temperature before the determining of the first concentration of the target material, such as N2O, in the first sample.

[0088] Embodiment 8. The method of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of disposing in the reservoir an amount of1452732480 1a remediation agent, wherein the remediation agent is configured to reduce the concentration of the target material, such as N2O, in the reservoir, and wherein the amount of the remediation agent is determined based on the first concentration, the second concentration, the comparing of the first concentration and the second concentration, or the comparing of any two of the second concentrations.

[0089] Systems

[0090] Embodiment 9. A system comprising, consisting essentially of. or consisting of -

[0091] a sensor;

[0092] a temperature modifying apparatus;

[0093] a sample channel comprising a sample input;

[0094] a cleaning liquid channel comprising a cleaning liquid input; and

[0095] one or more pumps and / or one or more pressurized lines;

[0096] wherein the one or more pumps and / or one or more pressurized lines is / are configured to transport a sample (e.g., the first sample and / or the second sample of any of the preceding Embodiments) from the sample input to the temperature modifying apparatus, and then to the sensor; and

[0097] wherein the one or more pumps and / or one or more pressurized lines also is / are configured to transport a cleaning liquid from the cleaning liquid input to the sensor.

[0098] Embodiment 10. The method or system of any of the preceding Embodiments, wherein the one or more pumps and / or one or more pressurized lines also is / are configured to transport the sample from the sensor to a reservoir from which the sample was collected (such as the reservoir of any of the preceding Embodiments).

[0099] Embodiment 11. The method or system of any of the preceding Embodiments, wherein the sample channel and the cleaning liquid channel merge to form a single channel, and optionally diverge from the single channel.

[0100] Embodiment 12. The method or system of any of the preceding Embodiments, wherein the sample channel and the cleaning liquid channel merge to form the single channel (i) upstream of the temperature modifying apparatus, or (ii) downstream of the temperature modifying apparatus and upstream of the sensor.

[0101] Embodiment 13. The method or system of any of the preceding Embodiments, wherein the sample channel and the cleaning liquid channel diverge from the single channel (i) upstream of the temperature modify ing apparatus, or (ii) downstream of the temperature modifying apparatus and upstream of the sensor.1552732480 1

[0102] Embodiment 14. The method or system of any of the preceding Embodiments, further comprising, consisting essentially of. or consisting of an apparatus, such as a second pump, that is configured to dispose a remediation agent in the reservoir.

[0103] Embodiment 15. The method or system of any of the preceding Embodiments, further comprising, consisting essentially of, or consisting of at least one controller, wherein the at least one controller is configured to operate and / or receive data from the sensor, the temperature modifying apparatus, the pump, the pressurized line, the apparatus configured to dispose a remediation agent in the reservoir, or a combination thereof.

[0104] Embodiment 16. The method or system of any of the preceding Embodiments, further comprising, consisting essentially of. or consisting of a housing, wherein the sensor, the temperature modifying apparatus, the sample channel, the cleaning liquid channel, or a combination thereof is / are at least partially arranged in or on the housing.

[0105] Collecting Samples

[0106] Embodiment 17. The method or system of any of the preceding Embodiments, wherein the collecting of the first sample of the fluid and / or the second sample of the fluid comprises, consists essentially of, or consists of -

[0107] collecting from the reservoir two or more portions of the fluid, wherein each of the two or more portions is collected from (i) a different location of the reservoir, (ii) the reservoir and an additional reservoir, or (iii) a combination thereof; and

[0108] combining the two or more portions of the fluid to form the first sample and / or the second sample, respectively, of the fluid.

[0109] Embodiment 18. The method or system of Embodiment 17, wherein the two or more portions includes a number of portions effective to prevent a concentration gradient of the target material, such as N2O, in the fluid from disrupting (e.g., by more than 1 %, more than 5 %, more than 10 %, more than 1 %, or more than 20 %) a correlation between (i) the first concentration and / or the second concentration of the target material, such as N2O, and (ii) a concentration of the target material, such as N2O, in the fluid in the reservoir (for example, if the concentration of the target material in the fluid of the reservoir is X, and a concentration gradient of the target material is present in the fluid, then the concentration gradient does not disrupt the correlation between the first concentration and the concentration of the target material by 5 % or more if the first concentration is from about 0.95X to about 1.05X).1652732480 1

[0110] Embodiment 19. The method or system of any of the preceding Embodiments, wherein the two or more portions includes exactly two portions, exactly three portions, exactly four portions, exactly five portions, or exactly six portions.[OHl] Embodiment 20. The method or system of any of the preceding Embodiments, wherein each of the different locations is a different vertical distance from the lowest point of the reservoir.

[0112] Modifying the Temperatures

[0113] Embodiment 21. The method or system of any of the preceding Embodiments, wherein the modifying of the first temperature comprises, consists essentially of, or consists of increasing or decreasing the first temperature.

[0114] Embodiment 22. The method or system of any of the preceding Embodiments, wherein the modify ing of the second temperature comprises, consists essentially of, or consists of increasing or decreasing the second temperature.

[0115] Calibration Temperatures

[0116] Embodiment 23. The method or system of any of the preceding Embodiments, wherein the calibration temperature is about 5 °C to about 40 °C, about 15 °C to about 30 °C, about 20 °C to about 30 °C, or about 20 °C to about 25 °C.

[0117] Embodiment 24. The method or system of any of the preceding Embodiments, wherein the predetermined range of deviation from the calibration temperature of the sensor is plus or minus about 10 °C, plus or minus about 9 °C, plus or minus about 8 °C, plus or minus about 7 °C, plus or minus about 6 °C, plus or minus about 5 °C, plus or minus about 4 °C, plus or minus about 3 °C, plus or minus about 2 °C, or plus or minus about 1 °C of the calibration temperature of the sensor.

[0118] Reservoirs and Fluids

[0119] Embodiment 25. The method or system of any of the preceding Embodiments, wherein the fluid comprises, consists essentially of, or consists of water.

[0120] Embodiment 26. The method or system of any of the preceding Embodiments, wherein the fluid comprises, consists essentially of, or consists of wastewater.

[0121] Embodiment 27. The method or system of any of the preceding Embodiments, wherein the fluid further comprises, consists essentially of, or consists of one or more microbial species, such as microbial species used in nitrogen removal processes, such as nitrification and denitrification.

[0122] Embodiment 28. The method or system of any of the preceding Embodiments, wherein the reservoir is a tank used in wastewater treatment.1752732480 1

[0123] Embodiment 29. The method or system of any of the preceding Embodiments, wherein the reservoir is an aeration tank.

[0124] Embodiment 30. The method or system of any of the preceding Embodiments, wherein the fluid in the reservoir is under aerobic conditions, which may be suitable for nitrification.

[0125] Embodiment 31. The method or system of any of the preceding Embodiments, wherein the fluid in the reservoir is under anoxic conditions, which may be suitable for denitrification. (As used herein, the phrase '‘anoxic conditions” refers to an environment that contains little (100 ppm or less, or 10 ppm or less) or no dissolved oxygen.)

[0126] Remediation Agents

[0127] Embodiment 32. The method or system of any of the preceding Embodiments, wherein the remediation agent comprises, consists essentially of, or consists of carbon, a carbon source, a pH modifier, or a combination thereof.

[0128] Sensors

[0129] Embodiment 33. The method or system of any of the preceding Embodiments, wherein the sensor comprises a metal cathode.

[0130] Embodiment 34. The method or system of any of the preceding Embodiments, wherein the sensor is in communication with a device for measuring electrical current, such as a picoammeter.

[0131] Embodiment 35. The method or system of any of the preceding Embodiments, wherein the sensor is configured to reduce the target material, such as N2O, at the cathode surface to produce an electrical current.

[0132] Embodiment 36. The method or system of any of the preceding Embodiments, wherein the device for measuring electrical current converts the electrical current to a signal.

[0133] Temperature Modifying Apparatus

[0134] Embodiment 37. The method or system of any of the preceding Embodiments, wherein the heating apparatus comprises, consists essentially of, or consists of a heating mantel, such as an electrical heating mantel.

[0135] Embodiment 38. The method or system of any of the preceding Embodiments, wherein the heating apparatus comprises, consists essentially of, or consists of a sensor, which may include a resistance thermometer, such as a PtlOO temperature sensor.1852732480 1

Claims

Claims -1. A method of sensing, the method comprising: providing a fluid in a reservoir, wherein the fluid comprises water and a target material; collecting from the reserv oir a first sample of the fluid, wherein the first sample is at a first temperature; modifying the first temperature of the first sample to a first modified temperature, wherein the first modified temperature is within a predetermined range of deviation from a calibration temperature of a sensor; and determining with the sensor a first concentration of the target material in the first sample.

2. The method of claim 1, further comprising:(i) collecting from the reservoir a second sample of the fluid, wherein the second sample is at a second temperature;(ii) modifying the second temperature of the second sample to a second modified temperature w ithin the predetermined range of deviation from the calibration temperature of the sensor; and(iii) determining with the sensor a second concentration of the target material in the second sample.

3. The method of claim 2, further comprising repeating steps (i), (ii), and (iii) one or more times.

4. The method of claim 2, further comprising contacting the sensor with a cleaning liquid (i) after the determining of the first concentration, and before the determining of the second concentration, or (ii) after the determining of the second concentration.

5. The method of claim 2, further comprising comparing the first concentration of the target material and the second concentration of the target material to determine whether the first concentration is greater than or less than the second concentration.1952732480 16. The method of claim 2, further comprising disposing in the reservoir an amount of a remediation agent, wherein the remediation agent is configured to reduce the concentration of the target material in the reservoir, and wherein the amount of the remediation agent is determined based on the first concentration, the second concentration, or a comparing of the first concentration and the second concentration.

7. The method of claim 6, wherein the remediation agent comprises carbon, a carbon source, a pH modifier, or a combination thereof.

8. The method of claim 1, wherein the calibration temperature is about 5 °C to about 40 °C, and the predetermined range of deviation from the calibration temperature of the sensor is plus or minus about 5 °C of the calibration temperature of the sensor.

9. The method of claim 1 , wherein the fluid comprises wastewater, and the target material is N2O.

10. The method of claim 1, wherein the collecting of the first sample of the fluid comprises: collecting from the reservoir two or more portions of the fluid, wherein each of the two or more portions is collected from a different location of the reservoir; and combining the two or more portions of the fluid to form the first sample of the fluid.

11. The method of claim 10, wherein the two or more portions includes a number of portions effective to prevent a concentration gradient of the target material in the fluid from disrupting by more than 10 % a correlation between (A) the first concentration of the target material, and (B) a concentration of the target material in the fluid in the reser oir.

12. A sy stem compri sing : a sensor; a temperature modifying apparatus; a sample channel comprising a sample input; a cleaning liquid channel comprising a cleaning liquid input; and2052732480 1one or more pumps, one or more pressurized lines, or a combination thereof; wherein the one or more pumps or the one or more pressurized lines are configured to transport (a) a sample from the sample input to the temperature modifying apparatus, and then to the sensor, (b) a cleaning liquid from the cleaning liquid input to the sensor, (c) the sample from the sensor to a reservoir from which the sample was collected, or (d) a combination thereof.

13. The system of claim 12, wherein the sample channel and the cleaning liquid channel merge to form a single channel upstream of the temperature modify ing apparatus, or downstream of the temperature modify ing apparatus and upstream of the sensor.

14. The system of claim 12, further comprising a housing, wherein the sensor, the temperature modifying apparatus, the sample channel, and the cleaning liquid channel are at least partially arranged in or on the housing.

15. The system of claim 12, wherein the sensor comprises a metal cathode and a device for measuring electrical current, and wherein the sensor is configured to reduce the target material at a surface of the metal cathode to produce an electrical current, and the device for measuring electrical current converts the electrical current to a signal.2152732480 1

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