Method for sanitisation, disinfection or sterilisation

Abstract

The present invention relates to a method for sanitising, disinfecting or sterilising microbially contaminated water-containing fluids, comprising treating the microbially contaminated water-containing fluid with an oxidising agent, wherein a fluorescence measurement is carried out on the water-containing fluid before, after and / or during treatment of the microbially contaminated water-containing fluid with the oxidising agent. The fluorescence measurement comprises irradiation with an excitation wavelength characteristic of a fluorescent protein and / or peptide building block and measurement of the corresponding fluorescence signal, and the method is characterised in that treatment with the oxidising agent proceeds in such a way that addition of the oxidising agent is controlled as a function of the fluorescence signal. The invention further relates to a corresponding device for sanitising, disinfecting or sterilising microbially contaminated water-containing fluid.

Description

[0001] METHOD FOR HYGIENIZATION, DISINFECTION OR STERILIZATION

[0002] The present invention relates to a method for sanitizing, disinfecting, or sterilizing microbiologically contaminated aqueous fluids, comprising treating the microbiologically contaminated aqueous fluid with an oxidizing agent, wherein a fluorescence measurement is performed on the aqueous fluid before, after, and / or during the treatment with the oxidizing agent, which includes irradiation with an excitation wavelength characteristic of a fluorescent protein and / or peptide building block and measuring the corresponding fluorescence signal, characterized in that the treatment with the oxidizing agent is carried out such that the addition of the oxidizing agent is controlled as a function of the fluorescence signal or its change over time. The present invention further relates to a device for sanitizing,Disinfection or sterilization of microbiologically contaminated aqueous fluid, comprising a container configured to hold microbiologically contaminated aqueous fluid, wherein the container includes a measuring cell that is at least transparent to light in the range of the intended fluorescence excitation wavelength and the corresponding fluorescence radiation, a supply device for oxidizing agent to the microbiologically contaminated aqueous fluid, a fluorescence measuring device comprising a light source configured to irradiate microbiologically contaminated aqueous fluid located in the measuring cell with light having an excitation wavelength characteristic of a fluorescent protein and / or peptide building block, preferably tryptophan, and a fluorescence detector suitable for measuring the corresponding fluorescence radiation, and a control or regulating device configured toto control or regulate the supply of oxidizing agent depending on the result of the fluorescence radiation measurement.

[0003] Different purity standards apply to water depending on its intended use. Drinking water, in particular, should be exceptionally clean and, above all, free from microbial contamination. Such contamination (for example, by coliform bacteria or Legionella) can lead to serious illnesses. Therefore, the quality of drinking water is constantly and comprehensively monitored. Water for swimming pools, on the other hand, should be odorless and not irritate the skin or eyes. Wastewater treatment serves primarily to protect the environment.

[0004] Water purification is carried out using appropriate methods depending on the application. In private households, for example, microbial contamination can be rendered harmless by boiling the water. WO 2012 / 084247 A1, on the other hand, describes a disinfection method that can be used both in private households and on a larger scale, and which uses an aqueous chlorine dioxide solution as a disinfectant for removing germs in drinking water pipes, air conditioning systems, water treatment plants, boilers, or pools.

[0005] To effectively reduce microbial contamination, it is often advantageous to first determine the microbial load of the water or other water-containing fluids. Once the extent of the microbial load is known, a suitable measure can then be applied to reduce the microbial contamination (for example, by selecting the duration of treatment or the amount of disinfectant).

[0006] Currently known methods are based on adding a reagent (or several reagents) to the aqueous system and the interaction of the reagent with the living organisms representing the microbial contamination. Typically, the reagent is bound by the living organism and then subsequently determined spectroscopically. However, this requires adding the reagent to the entire aqueous system, which is usually undesirable. Alternatively, a sample of the aqueous system can be taken first, and the reagent added to it. This, however, involves additional effort. A further state-of-the-art method involves cultivating germs on special nutrient media and visually evaluating the extent of microbial contamination. This, however, requires time (incubation of the plates) and also complex analysis.Non-invasive methods for detecting the presence of microbial contaminants in liquids are also known from the prior art. EP 1 329 514 A2, for example, discloses a method in which the fluorescence of fluorophoric components intrinsically contained in microbes (such as the amino acid tryptophan, flavins, porphyrins, etc.) is used to detect the microbes. It is explained that the fluorescence of, for example, the amino acid tryptophan can be used to detect viable and non-viable cells, spores, viruses, and toxins. However, this patent application does not relate to a method for sanitizing, disinfecting, or sterilizing microbiologically contaminated aqueous fluids.

[0007] Against this background, the present invention aims to provide an improved method for the hygienization, disinfection, or sterilization of microbiologically contaminated aqueous fluids. In particular, the present invention aims to provide a method by which hygienization, disinfection, or sterilization can be carried out in such a targeted manner that precisely the necessary amount of hygienizing, disinfecting, or sterilizing agent can be used. Furthermore, the present invention aims to provide a method in which the detection of microbial contamination does not require the addition of an additional reagent.Finally, the present invention aims to provide a suitable method for the broadest possible range of applications, for example in both continuous and batch processes.

[0008] This problem is solved by the embodiments characterized in the claims.

[0009] According to the invention, a method for the hygienization, disinfection or sterilization of microbiologically contaminated aqueous fluids is particularly described, comprising treating the microbiologically contaminated aqueous fluid with an oxidizing agent, wherein a fluorescence measurement is performed on the aqueous fluid before, after and / or during the treatment of the microbiologically contaminated aqueous fluid with the oxidizing agent, which includes irradiation with an excitation wavelength characteristic of a fluorescent protein and / or peptide building block and measuring the corresponding fluorescence signal, characterized in that the treatment with the oxidizing agent is carried out in such a way that the addition of the oxidizing agent is controlled as a function of the fluorescence signal or its change over time.

[0010] Within the scope of the present invention, the term "hygienization" is understood to mean a reduction of microbial impurities in the aqueous fluid by up to approximately 90%. "Disinfection" is understood to mean a further reduction of microbial impurities from approximately 90% to approximately 99.9%. "Sterilization" is understood to mean a substantially complete removal of microbial impurities (i.e., from approximately 99.9% to 100%), meaning that a sterilized aqueous fluid is essentially germ-free. The three terms thus differ in the degree of germ reduction. However, the present method applies equally to all three of these variants of germ reduction, even if they are not clearly distinguishable from one another.

[0011] The method according to the invention relates to the hygienization, disinfection, or sterilization of microbiologically contaminated aqueous fluids. The microbial contaminants are undesirable microbial components in the aqueous fluid. According to the invention, microbial components include, for example, bacteria (such as Legionella, coliform bacteria, cholera bacteria, vibrios, pseudomonads), fungi (such as Aspergillus), viruses (such as norovirus or hepatitis A), algae, toxins, spores, or protozoa. Preferably, the microbial components are bacteria, fungi, or viruses. Depending on the application, the aqueous fluid can be microbiologically contaminated to varying degrees. The degree of microbial contamination of the microbiologically contaminated aqueous fluid can be, for example, at least 10% before the addition of the oxidizing agent.The microbial count is typically 000 cells per ml, but for drinking water it can be significantly lower (for example, at least 100 cells per ml). However, it is also possible for the microbial count to be at least 20,000 cells per ml or even at least 50,000 cells per ml. The aqueous fluid can be any suitable aqueous fluid. This can be, for example, water, preferably drinking water, bath water, process water, wastewater, or cooling water. The aqueous fluid can also be an aqueous emulsion or dispersion. Microbial contamination of such aqueous fluids can lead to undesirable odors and also to an impairment of the lubricating properties. Preferably, the microbiologically contaminated aqueous fluid is drinking water, bath water, process water, wastewater, cooling water, process water, and / or aqueous cooling lubricants, for example, in the form of emulsions or dispersions.The microbially contaminated water-containing fluid is particularly likely to be drinking water, bathing water, process water or wastewater.

[0012] The process according to the invention comprises treating the microbiologically contaminated aqueous fluid with an oxidizing agent. Any suitable oxidizing agent can be used for this purpose, for example, chlorine dioxide, ozone, hydrogen peroxide, chlorine, or chloramines. Chlorine or chlorine dioxide is particularly preferred. According to the invention, chlorine dioxide is most preferably used as the oxidizing agent, as for example in

[0013] WO 2012 / 084247 A1 describes this process. The action of the oxidizing agent on the microbial impurities inactivates them, rendering them harmless.

[0014] Before, after, and / or during treatment of the microbially contaminated aqueous fluid with the oxidizing agent, a fluorescence measurement is performed on the aqueous fluid. This involves irradiation with an excitation wavelength characteristic of a fluorescent protein and / or peptide building block and measuring the corresponding fluorescence signal. For this purpose, the aqueous fluid is irradiated with light (e.g., laser light) of a specific excitation wavelength, and the corresponding fluorescence signal is measured at an angle of, for example, 90° with the corresponding emission wavelength. However, other suitable angles greater than 1°, such as 45°, are also possible. The person performing the measurement is familiar with the procedure. This measurement utilizes the fact that the microbial contaminants in the aqueous fluid contain fluorescent protein and / or peptide building blocks.Proteins and peptides contain, among other things, the fluorescent amino acids tryptophan (Trp), tyrosine (Tyr), and the comparatively weaker fluorescent amino acid phenylalanine (Phe) as building blocks. Therefore, the fluorescent protein or peptide building blocks tryptophan, tyrosine, and phenylalanine are preferred. The fluorescent protein or peptide building block tryptophan is particularly preferred, wherein irradiation with an excitation wavelength characteristic of tryptophan is carried out and the fluorescence signal characteristic of tryptophan is measured. The excitation wavelength of tryptophan is in the range of approximately 265 to approximately 300 nm, and the emission wavelength is in the range of approximately 300 to approximately 400 nm (depending on the local environment of the tryptophan).Within the scope of the present invention, an excitation wavelength in the range of approximately 275 to approximately 295 nm, and particularly preferably approximately 280 nm, and an emission wavelength in the range of approximately 340 to approximately 355 nm, and particularly preferably approximately 350 nm, are preferably used to detect the fluorescence of intrinsic tryptophan in the microbial impurities. For the also fluorescent amino acid tyrosine, the excitation and emission wavelengths can lie in the same range, with the fluorescence of tryptophan, which is also present in this range, often dominating.

[0015] According to the invention, the treatment with the oxidizing agent is carried out such that the addition of the oxidizing agent is regulated or controlled depending on the fluorescence signal or its change over time. This can be done in any suitable manner. The addition can be continuous or in intervals.

[0016] According to a preferred embodiment of the present invention, the addition of the oxidizing agent is controlled such that the intensity of the fluorescence signal does not exceed a predefined threshold. For example, if the intensity of the fluorescence signal is above the predefined threshold, the oxidizing agent is added at least until the threshold is undercut and remains below it. In a preferred embodiment, the oxidizing agent is added continuously so that the fluorescence signal remains permanently below the threshold. In another preferred embodiment, the oxidizing agent is added intermittently whenever the fluorescence signal approaches the threshold, thus preventing it from being exceeded.For example, if a reduction of microbial impurities by 99.9% is required for a specific application, the addition of the oxidizing agent is controlled by varying the duration and / or quantity until the target value is reached.

[0017] According to another preferred embodiment of the present invention, the addition of the oxidizing agent is controlled such that the first derivative of the fluorescence signal intensity does not exceed a predefined threshold. In this case, the change in the intensity of the fluorescence signal is therefore considered. This approach is based on the fact that microorganisms often exhibit exponential growth, in which the intensity of the fluorescence signal also increases, initially slowly and then ever more rapidly. According to this embodiment, the addition of the oxidizing agent is therefore controlled such that the rate of microbial growth (expressed by the first derivative of the fluorescence signal intensity) must not become too high. It is preferred that the first derivative assumes a negative value, at least temporarily, since this indicates a decrease in microbial impurities.In a preferred embodiment, the oxidizing agent is added continuously so that the fluorescence signal remains permanently below the threshold. In another preferred embodiment, the oxidizing agent is added intermittently whenever the fluorescence signal approaches the threshold, so that the threshold is not exceeded.

[0018] According to a further preferred embodiment of the present invention, the addition of the oxidizing agent is controlled such that the second derivative of the intensity of the fluorescence signal does not deviate significantly from a predefined value. Preferably, this predefined value is approximately zero. This indicates that the rate of change of microbial growth (and death) is kept essentially constant. This approach to controlling the addition of the oxidizing agent can be advantageous because some microorganisms exhibit a rather sharp decrease in the fluorescence signal upon addition of the oxidizing agent. This curve then has a different slope (after damage to the microorganisms = death), since fluorescence activity can still be measured by the residual fragments, which is reflected by a "kink" in the first derivative of the fluorescence signal.In this case, the oxidizing agent is preferably added until this inflection point in the first derivative of the fluorescence signal is reached, which as a result leads to the value for the second derivative being kept essentially constant.

[0019] The process according to the invention can, for example, be carried out continuously. In this process, the microbiologically contaminated aqueous fluid is preferably conveyed through a water-carrying system, particularly preferably a pipeline. The addition of the oxidizing agent can be controlled by adjusting the quantity and / or rate of addition of both the oxidizing agent and the microbiologically contaminated aqueous fluid. Continuous process operation is advantageous, for example, for the continuous treatment of drinking water, process water, or wastewater. Even if the process is continuous, this does not necessarily mean that the oxidizing agent must also be added continuously. Depending on the requirements, it may be sufficient to add the oxidizing agent only at specific intervals.

[0020] It is also possible to carry out the process according to the invention in a batch process. In this case, the amount and duration of the addition of the oxidizing agent to the microbially contaminated aqueous fluid are preferably controlled or regulated such that the addition is stopped when the intensity of the fluorescence signal or its first derivative for the fluorescent protein and / or peptide building block, preferably for tryptophan, has decreased to a value below the predefined threshold value.

[0021] However, even when using a batch process, it is possible to perform this process discontinuously or only at intervals. For example, microbial contaminants can form in a container with aqueous fluid over time, with growth often occurring exponentially. In a discontinuous batch process, the oxidizing agent can be added whenever a predefined threshold for microbial contamination is reached or exceeded. The addition of the oxidizing agent then reduces the contamination level back to a predefined value. From this point, however, renewed growth begins, so that if the upper threshold is exceeded again, another addition of oxidizing agent is triggered. In this way, the proportion of microbial contamination can be kept permanently within a predefined range.

[0022] In summary, the present invention provides an improved method for the hygienization, disinfection, or sterilization of microbiologically contaminated aqueous fluids by allowing the addition of oxidizing agent to be precisely controlled for the desired cleaning effect, depending on the actual amount of microbial contaminants present in the aqueous fluid. This avoids adding a larger quantity of oxidizing agent than absolutely necessary. This saves costs and prevents the fluid from being further burdened with unreacted oxidizing agent.

[0023] The microbial contamination is determined by measuring the autofluorescence of the membrane of the living organisms that constitute the microbial contamination; that is, the addition of further reagents to determine the microbial load is not necessary, unlike in the prior art described above. Accordingly, it is particularly preferred according to the invention that, in the process according to the invention, no further reagents, in particular no reagents required for measuring fluorescence, are added to the microbiologically contaminated aqueous fluid other than the oxidizing agent.

[0024] The invention takes advantage of the surprising finding that the oxidative destruction of microbial contaminants essentially eliminates their fluorescence (i.e., the fluorescence of the membrane of the living organisms that constitute the microbial contaminants), thus simplifying the monitoring of the success of sanitization, disinfection, or sterilization. In contrast, prior art, for example EP 1 329 514 A2, shows that even non-viable cells exhibit fluorescence, albeit reduced. Monitoring the success of purification is therefore considerably more complex, as the extent of residual fluorescence must first be determined as a reference point.

[0025] Furthermore, the method according to the invention can be used particularly advantageously for regulating and / or controlling hygienization, disinfection, or sterilization processes in water-bearing systems, since it can be operated directly online—but also offline or at-line—and has very short analysis times. Thus, hygienization, disinfection, or sterilization can be carried out automatically and as needed. Finally, the method according to the invention is applicable to the broadest possible range of applications, for example, in both continuous and batch processes.

[0026] The present invention further relates to a device for the hygienization, disinfection, or sterilization of microbiologically contaminated aqueous fluid, comprising a container configured to receive microbiologically contaminated aqueous fluid, wherein the container includes a measuring cell that is at least transparent to light in the range of the intended fluorescence excitation wavelength and the corresponding fluorescence radiation, a supply device for oxidizing agents to the microbiologically contaminated aqueous fluid, a fluorescence measuring device comprising: a light source configured to irradiate microbiologically contaminated aqueous fluid located in the measuring cell with light having an excitation wavelength characteristic of a fluorescent protein and / or peptide building block, preferably tryptophan; and a fluorescence detector suitable for measuring the corresponding fluorescence radiation.and a control or regulating device which is designed to control or regulate the supply of oxidizing agent depending on the result of the measurement of the fluorescence radiation.

[0027] The container can be open or closed, for example. It can also optionally include a stirring device. Within the scope of the present invention, the term "container" is used broadly. This includes, for example, water-carrying systems, preferably a pipeline. This device is preferably designed for continuous process operation. In this case, the container for microbiologically contaminated water-containing fluid is a water-carrying system, preferably a pipeline.

[0028] The container (including, for example, the pipeline) comprises a measuring cell that is at least transparent to light in the range of the intended fluorescence excitation wavelength and the corresponding fluorescence radiation. Such measuring cells are familiar to those skilled in the field. It is also possible for the measuring cell to be located outside the container, with a partial flow of the aqueous fluid being directed through a flow-through cuvette by a small pump, manually (for example, in an offline system), or by gravity for fluorescence measurement. If the container is a pipeline, the measuring cell can also preferably be a flow-through cuvette.

[0029] The device according to the invention further comprises a feed device for oxidizing agent to the microbially contaminated aqueous fluid. This feed device is connected to a control device, which is configured to control the feed of oxidizing agent depending on the result of the fluorescence measurement. Any suitable feed device can be used for this purpose. The control device also serves as an evaluation unit for the fluorescence measurement and is configured to trigger the addition of oxidizing agent, for example, when an adjustable limit value or a specific rate of increase of the fluorescence is reached. This addition can be in the form of a predetermined quantity of the oxidizing agent or the addition of several partial quantities of the oxidizing agent.In this process, the addition of the oxidizing agent in several partial steps can also be linked to the measured fluorescence of the fluid or the decrease in the fluorescence of the fluid per added subset of the oxidizing agent.

[0030] The device according to the invention further comprises a fluorescence measuring device, comprising a light source configured to irradiate microbiologically contaminated aqueous fluid located in the measuring cell with light of an excitation wavelength characteristic of a fluorescent protein and / or peptide building block, preferably tryptophan, and a fluorescence detector suitable for measuring the corresponding fluorescence radiation. In addition, the fluorescence measuring device may include further elements known to those skilled in the art, such as an optical slit, an optical bandpass filter, or a monochromator. The fluorescence detector may, for example, be a photodiode, preferably comprising a downstream amplifier. The light source may, for example, be an LED, preferably a UV LED with a driver circuit, emitting light of a suitable wavelength.The electronics of the fluorescence measuring device can be timed, so that measurements are not taken continuously, but at adjustable time intervals. This increases the lifespan of the LED and reduces the potential maintenance required for the sensor during operation.

[0031] The invention will now be described with reference to exemplary embodiments and schematic representations of devices according to the invention for the hygienization, disinfection or sterilization of microbially contaminated aqueous fluid.

[0032] Figure 1 shows a device according to the invention for a batch process.

[0033] Figure 2 shows a device according to the invention for continuous process control.

[0034] Figure 3 shows the schematic structure of a fluorescence measuring device for use in the device according to the invention.

[0035] Figure 4 shows the fluorescence of bacterially contaminated water over several cycles of oxidizing agent addition and bacterial growth.

[0036] Figure 1 shows a device 1 for the hygienization, disinfection, or sterilization of microbiologically contaminated aqueous fluid. This device comprises a container 2 with a stirring device 3 and a measuring cell 4. This cell is part of a fluorescence measuring device, which further comprises the light source 5 and the fluorescence detector 6. The device also includes a feed device for oxidizing agent 7 and a control unit.

[0037] Control device 8, which is configured to control or regulate the supply of oxidizing agent depending on the result of the fluorescence radiation measurement. This device is configured for carrying out sanitization, disinfection or sterilization in a batch process.

[0038] Figure 2 shows an alternative device 1 according to the invention, wherein the container 2 is designed in the form of a pipeline. This pipeline further includes an inlet 9 and an outlet 10. This device is designed for carrying out hygienization, disinfection, or sterilization in a continuous process.

[0039] Figure 3 shows the schematic setup of a fluorescence measuring device for use in the device 1 according to the invention. This device comprises a measuring cell 4 in the form of a flow-through cuvette, a UV LED with driver circuit as a light source 5, a photodiode as a fluorescence detector 6 with a downstream integrated amplifier, as well as an optical slit 11 and an optical bandpass filter 12, which has its transmission range in the region of the fluorescence wavelength. The optical slit 11 and the optical bandpass filter 12 are arranged in this order between the flow-through cuvette 5 and the fluorescence detector 6.

[0040] Example:

[0041] Hygienization of water contaminated with bacteria was carried out using a device according to Figure 1, which contains the fluorescence measuring device according to Figure 3.

[0042] Fluorescence measurement was performed by controlling the LED with electronics that allowed the current, and thus the illuminance, to be adjusted at the excitation wavelength, thereby adapting it to the required sensitivity. The detector consisted of a photodiode whose current was determined by the fluorescence radiation during the measurement. This current was amplified in an integrated amplifier and then fed to the control device, which was mounted in a light-tight housing. The intrinsic fluorescence of the amino acid tryptophan was determined at an excitation wavelength of 280 nm and a fluorescence wavelength in the range of 330–350 nm. It should be noted that this wavelength also depends on the chemical environment and can therefore vary compared to the pure substance.

[0043] A water bath was inoculated with E. coli bacteria at time ti, which then multiplied accordingly. The course of the fluorescence was monitored using the fluorescence measuring device as described above. When a preset fluorescence threshold was reached, the addition of chlorine dioxide was triggered.

[0044] The fluorescence (and thus the concentration of bacteria and any other microbial contaminants present) during various cycles of adding chlorine dioxide (ClO2) as an oxidizing agent and the intervening bacterial growth is shown in Figure 4. The addition of ClO2 at time t2 (0.1 mg / l) partially killed the bacteria and reduced them to a significantly lower, predefined level. During the subsequent period t4, renewed growth occurred before further sanitization at time ts (0.2 mg / l) (see Figure 4). Corresponding further cycles of sanitization by ClO2 addition and renewed bacterial growth result from the subsequent curves in Figure 4. Although E. coli was used as the inoculation in this experiment, the open operating procedure of the experiment does not preclude the possibility that other bacteria from the air were also introduced into the water.In the experiment, the addition of chlorine dioxide was regulated in such a way that a certain threshold of fluorescence (and thus of bacteria and any other microbial impurities that may be present) was not exceeded.

[0045] Reference symbol list

[0046] 1 Device for sanitizing, disinfecting or sterilizing

[0047] 2 containers

[0048] 3 Stirring device

[0049] 4 Measuring cell 5 Light source

[0050] 6 Fluorescence detector

[0051] 7 Feed device for oxidizing agent

[0052] 8 Control or regulating device 9 Pipe inlet

[0053] 10 Pipe outlet

[0054] 11 optical gap

[0055] 12 optical bandpass filters

Claims

Patent claims 1. A method for sanitizing, disinfecting, or sterilizing microbiologically contaminated aqueous fluids, comprising treating the microbiologically contaminated aqueous fluid with an oxidizing agent, wherein a fluorescence measurement is performed on the aqueous fluid before, after, and / or during the treatment of the microbiologically contaminated aqueous fluid with the oxidizing agent, which comprises irradiation with an excitation wavelength characteristic of a fluorescent protein and / or peptide building block and measuring the corresponding fluorescence signal, characterized in that the treatment with the oxidizing agent is carried out in such a way that the addition of the oxidizing agent is controlled depending on the fluorescence signal or its change over time.

2. The method of claim 1, wherein the addition of the oxidizing agent is controlled such that a) the intensity of the fluorescence signal does not exceed a predefined threshold, or b) the first derivative of the intensity of the fluorescence signal does not exceed a predefined threshold, or c) the second derivative of the intensity of the fluorescence signal does not deviate significantly from a predefined value.

3. The method of claim 1 or 2, wherein chlorine dioxide is used as the oxidizing agent.

4. Method according to any one of claims 1 to 3, wherein the fluorescent protein or peptide building block is tryptophan, the irradiation is carried out with an excitation wavelength characteristic of tryptophan and the fluorescence signal characteristic of tryptophan is measured.

5. Method according to any one of claims 1 to 4, wherein the microbiologically contaminated aqueous fluid is drinking water, bath water, This includes process water, wastewater, cooling water, process water and / or water-containing cooling lubricants, for example in the form of emulsions or dispersions.

6. A method according to any one of claims 1 to 5, which is carried out in a continuous process.

7. Method according to claim 6, wherein the microbiologically contaminated water-containing fluid is passed through a water-carrying system, preferably a pipeline.

8. Method according to claim 6 or 7, wherein the control of the addition of the oxidizing agent is effected by controlling the amount and / or rate of addition of oxidizing agent and microbiologically contaminated aqueous fluid.

9. A method according to any one of claims 1 to 5, which is carried out in a batch process.

10. Method according to claim 9, wherein the amount and duration of the addition of the oxidizing agent to the microbially contaminated aqueous fluid is controlled or regulated such that the addition is stopped when the intensity of the fluorescence signal or its first derivative for the fluorescent protein and / or peptide building block, preferably for tryptophan, is reduced to a value below the predefined threshold.

11. Method according to any one of claims 1 to 10, wherein no further reagents, in particular no reagents required for measuring fluorescence, are added to the microbially contaminated aqueous fluid other than the oxidizing agent.

12. Method according to any one of claims 1 to 11, wherein the degree of microbial contamination of the microbiologically contaminated aqueous fluid before the addition of the oxidizing agent is at least 10,000 cells per ml.

13. Device for sanitizing, disinfecting or sterilizing microbiologically contaminated aqueous fluid (1), comprising - A container (2) designed to receive microbiologically contaminated aqueous fluid, the container comprising a measuring cell (4) which is at least transparent to light in the range of the intended fluorescence excitation wavelength and the corresponding fluorescence radiation, - a feed device (7) for oxidizing agent to the microbiologically contaminated aqueous fluid, - a fluorescence measuring device comprising: o a light source (5) configured to irradiate microbiologically contaminated aqueous fluid located in the measuring cell with light having an excitation wavelength characteristic of a fluorescent protein and / or peptide building block, preferably tryptophan, and o a fluorescence detector (6) suitable for measuring the corresponding fluorescence radiation, and - a control or regulating device (8) which is designed to control or regulate the supply of oxidizing agent depending on the result of the measurement of the fluorescence radiation.

14. Device according to claim 13, which is designed for continuous process operation, wherein the container for microbiologically contaminated water-containing fluid (2) is a water-carrying system, preferably a pipeline.

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