Wastewater analysis system, method for improving sensitivity of wastewater analysis system, and method for improving sensitivity of wastewater

Abstract

The invention relates to a wastewater analysis system, a method for improving the sensitivity of the wastewater analysis system, and a method for improving the sensitivity of wastewater. A method for increasing the sensitivity of a wastewater analysis system to a primary analyte in a total sample of wastewater having the primary analyte and a secondary analyte, comprising at least the steps of: providing a wastewater analysis system comprising: detection means adapted to determine a primary analyte concentration of the primary analyte, wherein the primary analyte concentration is completely or partially related to the excrement concentration and / or ammonium concentration; a sensor adapted to determine a secondary analyte concentration of a secondary analyte; the sampler is suitable for taking out a plurality of sub-samples from the wastewater and storing the sub-samples; a calculation unit; a plurality of sub-samples are sequentially collected from the wastewater by a sampler for a predetermined time period for a predetermined time.

Description

Technical Field

[0001] The present invention relates to a method for collecting wastewater samples, a method for improving the sensitivity of a wastewater analysis system, and a wastewater analysis system. Background Art

[0002] In analytical measurement technology, especially in the fields of water management, environmental analysis, in industry, for example in food technology, biotechnology and medicine, and for the most varied laboratory applications, measured variables such as pH, conductivity or even the concentration of analytes, such as ions or dissolved gases in gaseous or liquid measurement media, are of great importance. These measured variables can be acquired and / or monitored, for example, by means of electrochemical sensors, such as optical sensors, potentiometric sensors, amperometric sensors, voltammetric sensors or coulometric sensors, or also by means of conductivity sensors. So-called analyzers serve to monitor process media regularly and fully automatically.

[0003] "Analyzer" in the sense of the present invention refers to a measuring device in process automation technology, which measures certain substance contents, such as, for example, the ion concentration in the medium to be analyzed, by means of wet chemical methods. For this purpose, a sample is taken from the medium to be analyzed. Usually, the acquisition of the sample is performed in a fully automatic manner by the analyzer itself by means of, for example, pumps, hoses, valves, etc. In order to determine the substance content of certain types, reagents specially developed for the corresponding substance content and reagents available in the housing of the analyzer are mixed with the sample to be measured. The color reaction of the mixture caused by this is then measured by an appropriate measuring device, such as, for example, a photometer. Therefore, the measured value is determined by the receiver based on light absorption and a stored calibration model.

[0004] The measurement system consisting of an analyzer and a sampler is usually operated so that the sampler collects samples from the wastewater system at a high frequency and fills the mixed samples into a bottle tray over a defined period of time (e.g., 1 h or 24 h) to mix and store them in a stable manner with the aid of cooling. The wastewater samples are concentrated for biomolecular wastewater analysis and then either impurities are eliminated or further concentrated by purification.

[0005] The extract obtained by concentration and purification is then checked for the presence of nucleic acids of the target organism, preferably in the laboratory, by means of PCR techniques. Alternatively, other analytical methods can be performed on the samples.

[0006] However, the problem here is that the analysis in the laboratory is very time-consuming and cost-intensive / material-consuming (due to expensive reagents, consumables, disposable tools) and therefore cannot be performed at the same frequency as the analyzer sampling. For this purpose, as mentioned above, the samples taken from the medium are mixed, whereby for example a sample period of 24 hours is mapped by 24 mixed samples. However, in the case of low analyte concentrations in the medium, it may happen that the present analyte concentration is below the feasible limit of the detection microbiological analysis (PCR) or the analytical system. Summary of the invention

[0007] It was therefore an object of the present invention to specify a method which allows a reliable, time-saving and cost-effective detection of analytes even at low analyte concentrations in a simple and efficient manner.

[0008] According to the present invention, this object is achieved by a method of increasing the sensitivity of a wastewater analysis system to a primary analyte in a bulk sample of wastewater having the primary analyte and a secondary analyte.

[0009] The method according to the present invention comprises at least the following steps:

[0010] - Provide wastewater analysis system, including:

[0011] a detection device adapted to determine a primary analyte concentration of a primary analyte, wherein the primary analyte concentration is fully or partially correlated with the fecal concentration and / or the ammonium concentration;

[0012] a sensor adapted to determine a secondary analyte concentration of the secondary analyte;

[0013] A sampler suitable for taking multiple subsamples from wastewater and storing the subsamples;

[0014] Computational unit;

[0015] - sequentially collecting a plurality of sub-samples from the wastewater at predetermined times within a predetermined time period by a sampler;

[0016] - store subsamples;

[0017] - determining, by the sensor, the concentration of the secondary analyte of the corresponding subsample;

[0018] - storing, by the calculation unit, the determined secondary analyte concentration of the respective subsample;

[0019] - evaluating the determined secondary analyte concentration by a calculation unit, wherein the secondary analyte concentration is determined within a predetermined area;

[0020] - selecting a stored subsample having a secondary analyte concentration in a predetermined region to form a total sample;

[0021] -Determine the primary analyte concentration of the total sample by the detection device.

[0022] The method according to the invention allows reliable detection of analytes even in the presence of low analyte concentrations in the medium. Since only one sample has to be analyzed, effort and cost are saved. The method further minimizes sampling effort and logistics, thereby saving costs. Therefore, the method improves the detection limit of the entire system of the workflow.

[0023] According to one embodiment of the present invention, the primary analyte is SARS-CoV-2 virus, norovirus, influenza virus, antibiotic-resistant bacteria, drug metabolites, hormones or biological particles and / or organisms or fragments thereof excreted via feces and / or urine.

[0024] According to another embodiment of the present invention, the predetermined time period is one day.

[0025] According to one embodiment of the invention, the evaluation step comprises an integration of the secondary analyte concentration, wherein during the selection step a selection of a maximum sub-integral is performed and a selection of a sub-sample corresponding to the maximum sub-integral as the total sample is performed.

[0026] According to one embodiment of the invention, the predetermined region comprises secondary analyte concentrations which deviate from the maximum secondary analyte concentration by less than 10%, preferably less than 5%, and which are sequentially close to the maximum secondary analyte concentration or sequentially close to the selected secondary analyte concentration.

[0027] According to one embodiment of the invention, the predetermined area is selected by artificial intelligence and / or an algorithm stored in a memory of the computing unit.

[0028] According to one embodiment of the invention, the predetermined region comprises a secondary analyte concentration greater than a predetermined threshold.

[0029] The aforementioned objects are also achieved by a wastewater analysis system.

[0030] The wastewater analysis system according to the present invention comprises:

[0031] - a detection device suitable for determining the primary analyte concentration of the primary analyte;

[0032] - a sensor adapted to determine a secondary analyte concentration of a secondary analyte;

[0033] - a sampler adapted to take a plurality of subsamples from the wastewater, store the subsamples and mix specific subsamples to form a total sample; and

[0034] -Computing unit for storing and evaluating the measurement data of detection devices and sensors.

[0035] According to one embodiment of the invention, the computing unit has a digital communication unit adapted to connect to a web-based database system.

[0036] The aforementioned objects are also achieved by a method for sampling wastewater having a primary analyte and a secondary analyte.

[0037] The method according to the present invention comprises at least the following steps:

[0038] -Sequential collection of wastewater subsamples;

[0039] - determining the secondary analyte concentration of the corresponding subsample;

[0040] - evaluating the determined secondary analyte concentration, wherein the secondary analyte concentration within a predetermined area is determined;

[0041] - selecting a subsample having a secondary analyte concentration in a predetermined area to form a total sample;

[0042] -Determine the primary analyte concentration of the total sample. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The present invention is explained in more detail based on the following description of the accompanying drawings. In the drawings:

[0044] Figure 1 A schematic diagram of a wastewater analysis system according to the present invention is shown;

[0045] Figure 2 A graph showing the ammonium content measured in the culture medium compared to the SARS-CoV-2 concentration. DETAILED DESCRIPTION

[0046] exist Figure 1 The wastewater analysis system 1 according to the present invention shown as an example in FIG. 1 comprises a detection device 10 , a sensor 20 , a sampler 30 , a calculation unit 40 and a database 50 .

[0047] The wastewater analysis system 1 is fluidly supplied with wastewater A. Wastewater A has a primary analyte A1 and a secondary analyte A2. For example, the wastewater analysis system 1 is connected to a wastewater tank or wastewater channel of a sewage treatment plant or a cesspool via a hose. Wastewater A includes human and / or animal excrement and / or urine. Figure 1 The wastewater analysis system 1 is shown as a central unit. However, the different components of the wastewater analysis system 1 can also be arranged remotely.

[0048] The detection device 10 is suitable for determining the primary analyte concentration AK1 of the primary analyte A1. The primary analyte A1 is preferably SARS-CoV-2. In an alternative embodiment, the primary analyte A1 is a different virus or organism. The primary analyte A1 is, for example, an influenza virus, a norovirus, an antibiotic-resistant bacteria, a drug, a drug metabolite, or a radioactively contaminated agricultural fertilizer. The primary analyte A1 is, for example, a nucleic acid of a pathogen (e.g., a virus, a bacteria) or a nucleic acid of another biological particle or organism, whose concentration in the wastewater is of concern. The biological particle or organism to be detected may be present in the wastewater as a whole or only in fragments or only as genetic material. The primary analyte A1 includes, for example, a hormone or a drug.

[0049] The detection device 10 preferably includes a filtration unit for concentrating the primary analyte A1. The detection device 10 is suitable for guiding the wastewater through the filtration unit by means of compressed air and / or mechanical pressure. The filtration unit is suitable for separating the liquid phase by static interaction or size exclusion. For example, the filtration unit includes a cellulose mixed ester membrane. The filtration unit further includes a purification unit, such as a magnetic silicate bead. The purification unit is suitable for concentrating primary analytes such as nucleic acids and removing impurities. PCR technology is preferably used to detect the primary analyte A1. Different technologies that are sensitive to the corresponding analytes can also be used instead of PCR technology. The detection device 10 is, for example, spatially separated from the sensor 20, the sampler 30 and the computing unit 40 (not shown). The detection device 10 is, for example, located in a laboratory. Of course, the detection device 10 can also be directly coupled to the sensor 20, the sampler 30 and the computing unit 40.

[0050] The sensor 20 is adapted to determine a secondary analyte concentration AK2 of a secondary analyte A2. The secondary analyte A2 is for example ammonium or another fecal marker, such as chemical oxygen demand (COD). The sensor 20 is for example an optical sensor, preferably a photometric sensor, such as a UV absorption sensor.

[0051] The sampler 30 is adapted to take a plurality of subsamples 32 from the wastewater A. Furthermore, the sampler 30 is adapted to store the subsamples 32 taken from the wastewater A in, for example, a cooling container, so that the subsamples 32 remain chemically / biologically / physically stable. Furthermore, the sampler 30 is also adapted to select the subsamples 32 and to mix these specific subsamples 32 to form the total sample 31. The sampler 30 is also adapted to automatically discard the collected samples / subsamples according to predefined limit values ​​or time intervals, and thus to fully automatically initialize a new sampling cycle. Alternatively, of course, the mixing of the subsamples or the discarding of the samples can also be done manually.

[0052] The computing unit 40 preferably has a memory and is adapted to store and evaluate the measurement data from the detection device 10 and the sensor 20. The computing unit 40 is preferably also adapted to control the detection device 10, the sensor 20 and the sampler 30. The computing unit 40 is, for example, a microcontroller or other computing unit. The computing unit 40 preferably has a digital communication unit, which is adapted to be connected to a web-based database system 50, so as to continuously, i.e., in real time, transmit, store and graphically provide the obtained measurement results and status information of the wastewater analysis system 1 to the user. The computing unit 40 and / or the web-based database system 50 are adapted to, for example, generate and send an alarm message to the user in real time, so as to inform the user about the exceeding of a limit value or about the occurrence of the analyte A1.

[0053] A method for increasing the sensitivity of the wastewater analysis system 1 to the primary analyte A1 in the total sample 31 from the wastewater A according to the present invention is described below.

[0054] The method comprises at least the following steps:

[0055] In a first step, the above-described wastewater analysis system 1 is provided. This means that the wastewater analysis system 1 is supplied with wastewater A and is ready for operation.

[0056] In the next step, a plurality of subsamples 32 are sequentially obtained from the wastewater A by the sampler 30. The subsamples 32 are collected at predetermined times T1, T2. For example, they are collected every hour or every 10 minutes. The collection occurs within a predetermined time period T, for example within a day. The subsample 32 has a volume of, for example, 100 ml to 50 liters. Preferably, volume proportional sampling is performed. Depending on the volume of the total flow of the sample source, such as a sewage treatment plant, the volume of the subsample is defined proportionally to this value. A single sampling occurs within a few seconds, for example by suction of the sample or by a compressed air system. The subsample 32 is filled into a container by the sampler 30, for example, into a bottle arranged in a bottle tray. The container is, for example, arranged as a carousel with 24 bottles, which are filled sequentially. Therefore, a bottle tray with, for example, 24 bottles represents a day. Of course, more or fewer containers for receiving subsamples 32 can also be provided. The subsamples 32 are preferably numbered or filled into numbered containers.

[0057] Next, the sub-sample 32 is stored. Preferably, the sub-sample 32 is stored in the sampler 30 so as to be cooled. This enables the sub-sample 32 to remain stable.

[0058] The step of determining the secondary analyte concentration AK2 of the respective subsample 32 is then performed by the sensor 20. Preferably, the determination step occurs simultaneously with the sampling. The concentration of ammonium (NH4-N) is determined by means of a photometric analysis performed by the sensor 20, wherein a reagent is metered into the respective subsample 32, which results in a color change that depends on the NH4-N concentration. This color change is then measured by a sensor, in particular a photometer. Including a sample with a known NH4-N concentration allows the measurement system to be linearized, which therefore allows the NH4-N concentration of the sample to be determined. The linearization is specifically performed as follows: First, the raw value absorption is determined for the included reference. The included reference is a known NH4-N concentration. The raw value of the absorption of a reference with zero concentration (e.g., a cleaning solution) is then determined. By means of a linear correlation between the determined absorption and the known NH4-N concentration, the application of a first-order function can be (linearly) applied.

[0059] In a next step, the determined secondary analyte concentration AK2 of the respective subsample 32 is stored by the computing unit 40. The secondary analyte concentration AK2 determined for each subsample 32 is stored in the memory of the computing unit 40 for later evaluation. Figure 2 An exemplary development of the secondary analyte concentration AK2 over 24 hours is shown based on the curve represented by the solid line. Figure 2 In the example shown, the secondary analyte concentration AK2 is not measured discretely but quasi-continuously, ie in very short time intervals between sampling times Ti. However, since the measurement points are connected to each other for illustration purposes, the curve appears as a continuous curve.

[0060] A step of evaluating the determined secondary analyte concentrations is then performed by the calculation unit 40. This step is preferably performed at the end of each day, i.e. after the 24-hour subsamples 32 have been taken from the wastewater A and filled into the container. The evaluation step preferably comprises determining the maximum secondary analyte concentration AKmax from all the secondary analyte concentrations AK2 of all the subsamples 32 (see Figure 2 ). In addition, for example, all secondary analyte concentrations AK2 arranged in a predetermined area B around the maximum secondary analyte concentration AK2 are determined.

[0061] According to an alternative embodiment, the evaluation step comprises integrating the ammonium concentration curve between the time intervals of the wastewater sampling, subsequently selecting the largest sub-integral and thus the most relevant wastewater sub-sample. Such an evaluation is meaningful in particular in the case of time-proportional sampling. In the case of volume-proportional sampling, an additional multiplication of the sub-integral with the corresponding flow volume flow is performed. This results in a load value (i.e. the integral of the ammonium load). Subsequently, the largest ammonium load sub-integral is selected and thus the corresponding most relevant wastewater sample is selected.

[0062] The predetermined region B preferably includes secondary analyte concentrations AK2 which deviate from the maximum secondary analyte concentration AKmax by less than 10%, preferably less than 5%, and which sequentially approach the maximum secondary analyte concentration AKmax or sequentially approach the selected secondary analyte concentration AK2. "Sequentially approaching" is understood here to mean that a measured value - i.e. a determined concentration - is determined directly before or after another measured value.

[0063] According to an alternative embodiment, the predetermined region B is selected by an artificial intelligence stored in the memory of the computing unit 40. This means that the artificial intelligence is fed with the input variables: secondary analyte concentration AK2, sampling time Ti, flow rate (in the case of volumetric proportional sampling) and other data, such as weather data and / or weather forecast data. The artificial intelligence then outputs an optimal region B, which represents a specific secondary analyte concentration AK2 or an associated subsample 32. Thus, the artificial intelligence outputs, for example, the number of subsamples 32 that fall into region B.

[0064] According to an alternative embodiment, the predetermined region B comprises such secondary analyte concentrations AK2 which are greater than a predetermined threshold value S. The threshold value S is, for example, the average value between the highest measured secondary analyte concentration AK2 and the lowest measured secondary analyte concentration AK2.

[0065] In a next step, the subsample 32 associated with the maximum secondary analyte concentration AK2 and the subsamples 32 having the secondary analyte concentration AK2 in the predetermined area B are selected. Since the subsamples 32 are preferably numbered, the calculation unit 40 preferably determines the number of subsamples 32 .

[0066] In case several subsamples 32 are selected, i.e. located in the predetermined area B, a step of mixing the selected relevant subsamples 32 to form the total sample 31 occurs by the sampler 30. The total sample 31 is preferably filled into a container large enough to receive the subsamples 32, or transferred from a container of subsamples 32 to a container of the total sample 31. The mixing step is performed, for example, automatically or manually. The mixing step is particularly advantageous in the case of subsamples 32 of very small volumes, for example 100 ml.

[0067] Furthermore, a step of determining the primary analyte concentration AK1 of the total sample 31 is performed by the detection device 10. This step takes place, for example, in the wastewater analysis system 1. However, according to alternative embodiments, this step can also take place geographically remote from other components present in the wastewater analysis system 1, for example in a laboratory. The detection device 10 preferably performs a PCR analysis with the total sample 31, wherein nucleic acids are detected and quantified. As described above, if the primary analyte A1 is, for example, a drug metabolite, another analysis system can also be used to determine the primary analyte concentration AK1.

[0068] Figure 2 An example of a distribution of primary analyte concentrations AK1 determined from a plurality of sequential subsamples 32 is shown based on the dashed curve. However, no selection of the subsamples 32 is performed here based on their secondary analyte concentrations AK2.

[0069] from Figure 2 As can be seen in the figure, there is a correlation between the concentration of ammonium and the concentration of SARS-CoV-2 virus. Since the SARS-CoV-2 virus is particularly present in excreta, and since the presence of excreta in wastewater A increases the concentration of ammonium, ammonium can be used as an indicator for the optimal sampling period or optimal selection of wastewater samples.

[0070] Thanks to the invention, the detection limit of the entire system (consisting of sampling and sample processing and analysis) is lowered by the ammonia-dependent selection of the sample. Thus, the wastewater analysis system 1 is more sensitive, since samples with a high viral load are no longer mixed with samples with a low sample load (as described previously) before being analyzed by the detection device 10. Due to the selection of samples in zone B, a dilution or attenuation of the concentration of the analyte to be analyzed is avoided, if it is assumed that the analyte does not exist in the same concentration at all times of the day.

[0071] Furthermore, the present invention makes it possible that, as a result of sample processing and analysis of subsamples in a specific relevant area B, sampling may theoretically not be carried out over the entire day, but only over a reduced time period T', if the daily concentration profile is almost the same, leading to further effort and cost savings during sampling.

[0072] The wastewater analysis system 1 according to the present invention reduces the logistical, labor, material, time and cost efforts associated with sample transportation, preparation and analysis.

[0073] Thanks to the present invention, the detection limit of the wastewater analysis system 1 can be improved and erroneous epidemiological conclusions (such as false negatives) can be avoided.

[0074] List of reference symbols

[0075]

Claims

1. A method for increasing the sensitivity of a wastewater analysis system (1) to a primary analyte (A1) in a total sample (31) of wastewater (A) having a primary analyte (A1) and a secondary analyte (A2), wherein: The method comprises at least the following steps: -Providing the wastewater analysis system (1), comprising: a detection device (10) adapted to determine a primary analyte concentration (AK1) of the primary analyte (A1), wherein the primary analyte concentration (AK1) is fully or partially correlated with a fecal concentration and / or an ammonium concentration; a sensor (20) adapted to determine a secondary analyte concentration (AK2) of the secondary analyte (A2); A sampler (30), the sampler (30) being adapted to take a plurality of subsamples (32) from the wastewater (A) and to store the subsamples (32); · Computational unit (40); - sequentially collecting the plurality of sub-samples (32) from the wastewater (A) at predetermined times (T1, T2) within a predetermined time period (T) by the sampler (30); - storing the subsample (32); - determining the secondary analyte concentration (AK2) of the corresponding subsample (32) by means of the sensor (20); - storing the determined secondary analyte concentration (AK2) of the respective subsample (32) by the calculation unit (40); - evaluating the determined secondary analyte concentration (AK2) by the calculation unit (40), wherein the secondary analyte concentration (AK2) is determined within the predetermined area (B); - selecting a stored subsample (32) having a secondary analyte concentration (AK2) in said predetermined area (B) to form said total sample (31); - determining the primary analyte concentration (AK1) of the total sample (31) by the detection device (10).

2. The method according to claim 1, wherein: The primary analyte (A1) is SARS-CoV-2 virus, norovirus, influenza virus, antibiotic-resistant bacteria, drug metabolites, hormones or biological particles and / or organisms excreted via feces and / or urine or fragments thereof.

3. The method according to claim 1 or 2, wherein: The predetermined time period (T) is one day.

4. A method according to any one of the preceding claims, wherein: The evaluation step comprises an integration of the secondary analyte concentration (AK2), wherein the selection step performs a selection of a maximum sub-integral and performs a selection of the sub-sample (32) corresponding to the maximum sub-integral as the total sample (31).

5. A method according to any one of the preceding claims, wherein: The predetermined region (B) includes a secondary analyte concentration (AK2) that deviates from a maximum secondary analyte concentration (AKmax) by less than 10%, preferably less than 5%, and sequentially approaches the maximum secondary analyte concentration (AKmax) or sequentially approaches a selected secondary analyte concentration (AK2).

6. A method according to any one of the preceding claims, wherein: The predetermined area (B) is selected by artificial intelligence and / or an algorithm stored in the memory of the computing unit (40).

7. A method according to any one of the preceding claims, wherein: The predetermined region (B) includes a secondary analyte concentration (AK2) greater than a predetermined threshold (S).

8. A wastewater analysis system (1), comprising: - a detection device (10) suitable for determining a primary analyte concentration (AK1) of a primary analyte (A1); - a sensor (20) adapted to determine a secondary analyte concentration (AK2) of a secondary analyte (A2); - a sampler (30) adapted to take a plurality of subsamples (32) from said wastewater (A), store said subsamples (32) and mix specific subsamples (32) to form a total sample (31); and - a computing unit (40) for storing and evaluating the measurement data of the detection device (10) and the sensor (20).

9. The wastewater analysis system (1) according to claim 8, wherein: The computing unit (40) has a digital communication unit adapted to connect to a network-based database system (50).

10. A method for sampling wastewater (A), the wastewater (A) having a primary analyte (A1) and a secondary analyte (A2), wherein: The method comprises at least the following steps: - sequentially collecting subsamples (32) of said wastewater (A); - determining the secondary analyte concentration (AK2) of the corresponding subsample (32); - evaluating the determined secondary analyte concentration (AK2), wherein the secondary analyte concentration (AK2) within the predetermined area (B) is determined; - selecting said subsample (32) having a secondary analyte concentration (AK2) in said predetermined area (B) to form a total sample (31); - Determining the primary analyte concentration (AK1) of said total sample (31).

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