LU500009B1 - WATER TOXIC SUBSTANCES MONITORING DEVICE AND SYSTEM INCLUDING THIS - Google Patents

Abstract

A device (30) for monitoring toxic substances in water and a system comprising the same. The device comprises a reference chamber (1) with a purification filter (8) and a monitoring chamber (2) with an inert filter (9). The two chambers (1, 2) each further include an inlet and an outlet for the flow of water and houses a biofilm (5) and a fluorimeter (6) for measuring fluorescence. A data acquisition unit (18) acquires measurements from the fluorimeter (6) of each chamber (1, 2) which can be compared to identify changes in the aquatic environment. In both chambers can be incorporated passive sensors for organic (3) and inorganic (4) pollutants which, once analyzed in the laboratory, make it possible to supplement the results obtained from the biofilm. The system includes a remote computer (21) for transmitting alarms to the terminals (22). FIG. 1

Description

BL-5222 LU500009 DEVICE FOR MONITORING TOXIC SUBSTANCES IN WATER AND SYSTEM INCLUDING THIS Technical field of the invention

The invention belongs to the field of water quality and safety monitoring.

More specifically, it relates to systems and methods for the early detection of micropollutants in surface waters.

STATE OF THE ART Traditionally, the evaluation of toxic substances in water is based on the sampling of water and the extraction and analysis of pollutants by chromatography and mass spectrometry, but chemical analysis is expensive and time consuming.

Specialized technicians are needed for sampling and analysis.

Compounds can only be detected in previously calibrated detection instruments.

Due to the limited information on the toxic effects of the mixtures, there are difficulties in assessing the impact.

In situ probes are currently available for aquatic ecosystems - capable of transmitting signals and alerts, although they only measure hydraulic parameters (e.g. water level, flow) and inorganic chemical components ( e.g. oxygen, pH, suspended solids, etc.). In general, these probes have several drawbacks: they are intended for specific substances and / or they are designed for laboratory use and / or they are expensive and / or they require extensive maintenance and / or the interpretation of the results is difficult. hard.

Some analytical techniques use biofilms (also called bacterial mats or microbial mats) as a bioindicator of water quality and safety.

By biofilm is meant a film formed by microalgae, diatoms and bacteria.

In general, these analytical techniques must be performed in situ and provide unreliable results.

They exhibit high variability and are subject to interpretation, so they are often impractical.

BL-5222 LU500009 On the one hand, indicators based on biofilm are influenced by a multitude of variables not necessarily linked to water pollution, such as light intensity, suspended solids, nutrients, nitrates, nitrites , phosphorus, temperature, water flow, etc., which affect the validity of the results.

On the other hand, the biofilm can adapt to water conditions and develop specific resistances that affect its sensitivity. Therefore, the results of indicators based on biofilm may be biased.

Brief description of the invention In view of the limitations observed in the state of the art, the need to improve the diagnosis of water has been observed.

In addition, rapid detection would be desirable, especially in places of interest. For example, at the outlet of wastewater treatment plants (STEP) or at drinking water distribution points.

The present invention is designed to address these and other problems. A device is proposed having the technical characteristics of the independent claim. Particular and advantageous embodiments are defined in the dependent claims.

In general, there is provided a device for monitoring toxic substances in water which comprises a first reference chamber with a purification filter and a second monitoring chamber with an inert filter. The two chambers are submersible and each include: an inlet and outlet for water flow, a housing module to house at least one biofilm, and a fluorimeter to measure fluorescence in the biofilm. During use, the housing module must receive exterior light for the biofilm. The device further comprises a data acquisition unit for collecting the measurement of the fluorescence of the biofilm in each chamber. Thus, a local comparison can be made between a biofilm with water purified of toxic substances and another biofilm with untreated water and, at the same time, discriminate changes due to pollutants. This specificity makes it possible to exclude changes in the biofilm caused by other factors. For example, there are variations in climatic conditions which are not related to pollution, but which cause changes

BL-5222 ’LU500009 in the biofilm and which, therefore, could generate false positives for pollution.

Another advantage of the device is that it can be designed in a versatile way depending on the working environment. For example, the filter material can be chosen depending on the type of pollutants to be retained.

Optionally, the device can integrate passive sensors for organic pollutants and metals. Through the extraction of the sample contained in the passive sensor and its analysis, which can be analyzed later in the laboratory, the use of these passive sensors in the device provides additional information. Said additional information serves to confirm that the changes in the biofilm are in fact due to pollutants. Likewise, it is also used to recognize if the filters are working correctly.

Optionally, the device can have a data transmission system. The data transmission system can communicate with other remote systems responsible for examining the information and acting on it. For example, it can take actions such as generating alarms for pollution type, maintenance warnings, etc. It is also compatible with other tools and accessories that can be integrated to meet specific requirements.

The invention also provides a system that incorporates one or more monitoring devices for toxic substances in water and, further, a remote computer in communication with each monitoring device. The computer is programmed to compare the measurements acquired in the two chambers of each device and also to send an alarm to one or more monitoring terminals depending on the result of the comparison. These terminals are electronic devices such as mobile phones, tablets, computers, etc. Brief description of the figures To complete the description which is in progress and in order to aid a better understanding of the features of the invention, a set of drawings is attached as an integral part of said description, where the following has been shown by way of illustration and not limitation:

BL-5222 LU500009 Figure 1.- Schematic block diagram according to one embodiment of the device. Figure 2.- Diagram of the chambers according to one embodiment of the device. Figure 3.- Schematic exploded view of one of the chambers according to one embodiment of the device.

Numerical references 1 Reference chamber. 2 Surveillance room. 3 Passive sensor for organic pollutants.

4 Passive sensor for inorganic pollutants. 5 Biofilm. 6 Fluorimeter. 7 Passage membrane. 8 Purifying filter.

9 Inert filter. 10 Housing module. 14 Exit hole for wiring. 16 Submarine cable. 17 Closure.

18 Data acquisition unit. 20 Server in the cloud. 21 Remote computer. 22 Monitoring terminal 23 Data communication unit.

24 Warning sign. 26 Renewable energy production system. 27 Screw. Device for monitoring toxic substances.

BL-5222) LU500009 Detailed description of the invention In Figure 1 there is shown schematically a block diagram according to one embodiment, the monitoring device 30 allows, continuously, early detection of the presence of pollution in the 'water.

Device 30 uses biofilm 5. Biofilm 5 is a very sensitive living community and serves as the primary sensing element.

The device 30 has a configuration which avoids interpretation errors generated by external factors unrelated to the presence of pollutants to be detected.

In operation, the device 30 detects the changes by means of measurements of fluorescence of the biofilm 5 carried out in two different spaces, immersed in the aquatic environment, by means of its corresponding fluorimeter 6.

A first space serves as a local reference to have the environmental conditions without toxic substances.

In a second space, changes in the environment due to the presence of toxic substances are monitored.

To create these two spaces in contact with the aquatic environment, bedrooms 1, 2 are designed.

Among other specific properties, the two chambers 1, 2 must allow the development of the appropriate biofilm 5.

In the event of pollution, one of them, the reference chamber 1, must keep the biofilm 5 in water purified of pollutants, in order to be able to identify in this way the change undergone by the other biofilm 5 which is found in monitoring chamber 2 exposed to existing pollutants in the environment.

In the reference chamber 1, the incoming water is purified from pollutants, but retains other characteristics (temperature, pH, nutrients, etc.). The measurements of the biofilm 5 of each chamber 1, 2 are compared.

Based on this comparison, if there is a significant difference, the monitoring device 30 is able to generate a warning signal.

With this warning signal, an alert can be issued.

For example, the warning signal can be easily transmitted using wireless technology such as WiFi.

The monitoring device 30 thus makes it possible to continuously check the quality of the water.

The design also allows for the use of passive sensors to detect pollution by pharmaceutical compounds and heavy metals, among others.

For this, it can integrate, in addition to a biofilm 5, a passive sensor for inorganic pollutants 4 (DGT, by its initials in English) and a passive sensor for organic pollutants

BL-5222 LU500009 3 (POCIS, by its initials in English). These passive sensors 3, 4 can be used as a support for chemical analysis and the identification of pollutants. The type of fluorimeter 6 used is preferably amplitude modulated pulses for rapid assessment of changes in structural and functional indicators. To establish whether the measurement differences of the fluorimeter 6 in the reference chamber 1 and the fluorimeter 6 in the monitoring chamber 2 are significant, they are calibrated in the field and in the laboratory. It should be noted that Biofilm 5 is generally grown under clean water conditions. The biofilm 5 reacts to exposure to pollutants with changes in functional parameters (for example, efficiency of photosynthesis, basal fluorescence, etc.) These changes are detectable by the fluorimeter 6. Advantageously, the presence of a local reference avoids false positives. Often, external factors unrelated to toxicity can affect the values measured in the biofilm. For example, these parameters are influenced by temperature, turbidity or nutrients. Previously, appropriate calibration is performed in the laboratory. With the measurements, different parameters can be obtained, among which we can mention mainly: - YII, photosynthetic efficiency (photosynthetic yield, in English), with a theoretical range of 0 to 100%, and with normal values for a biofilm in good condition. conditions between 60% and 70%; - Basal fluorescence: it represents an indirect measure of biomass and can increase or increase or remain constant during exposure (the range depends on the calibration of the sensor carried out before installation); - Y (NPQ), regulated non-photochemical attenuation (in English: yield of regulated non-photochemical fluorescence quenching), which represents the energy emitted by cells in the form of heat, it is a mechanism of protection and an indicator of stress ; - Y (NO), unregulated non-photochemical attenuation (in English: yield of non-regulated non-photochemical fluorescence quenching), this parameter indicates a dysfunction of the photosynthetic and / or protection mechanisms.

In fact: YII + Y (NPQ) + Y (NO) = 100%, if cells lower their energy through photosynthesis, the energy expended as heat or used, for example, for detoxification, will increase. Laboratory tests indicate the relationship between effect and

BL-5222 LU500009 toxic mixture. The local reference also makes it possible to appreciate small variations which would be confused with effects by non-toxic factors. The monitoring device 30 can be coupled to a data acquisition unit 18 (which can be submersible) wired to a surface equipment 19, located out of the water and powered by an energy production system 26, by example, renewable energy for greater autonomy. In said surface equipment 19, a communication unit makes it possible to send the information acquired for processing, for example, to a remote computer 21 which, among other actions, is responsible for issuing an alert based on the data received. . Different types of alerts can be established depending on the estimated degree of toxicity. Referring to Figures 2 and 3, the operation and additional constructive details of particular embodiments of the toxic substance monitoring device 30 are explained for a more complete understanding.

In Fig. 2 are shown various details of the use and configuration of one embodiment of the monitoring device 30. The monitoring chamber 1 and the reference chamber 2 are installed in the direction of the flow of water. water so that the current carries any pollutants to the sensors. Both chambers can be made with a cylindrical shape of methacrylate (PMMA), sometimes commonly referred to as Plexiglas (the brand under which it is marketed) with a thickness of around 3mm and a capacity of several liters. In the reference chamber 1, the water passes through a passage membrane 7 and reaches a purifying filter 8 made of activated carbon. When the activated carbon is in the form of grains, the purifying filter 8 comprises elements, for example, a housing also made of PMMA material, or another inert material (or another material with similar characteristics), with a base perforated to allow the exit of water, but not that of charcoal, this perforated base has holes - regular of 1-2 mm in diameter. To prevent the accidental release of granular activated carbon, an additional 5 mm thick layer of glass wool or other inert semi-permeable membrane can be added to the base of the filter. In this way, the water reaches the clean, material-free biofilm 5 from the filter itself.

BL-5222; LU500009 In the monitoring chamber 2, the water passes through a passage membrane 7 to the inert glass wool filter 9 where it reaches the uncleaned biofilm 5. The inert filter 9 comprises the same elements of the purifying filter 8 except that it is filled with glass wool instead of activated carbon.

Chambers 1, 2 are specially designed to ensure that biofilm 5 has the flow of water, light and specific nutrients to survive. Among other considerations, it must allow the passage of light, be strong enough to withstand working conditions, and be inert to the substances to be analyzed. For example, PET is not suitable because it can adsorb pollutants. Preferably, it should be a low cost material resistant to acids and dilute solvents so that it is easy to clean. || It must be taken into account that the other components of each chamber 1, 2, such as screws or rivets, for example, must also be made of inert materials. For these parts, stainless steel or polytetrafluoroethylene (PTFE), also called Teflon, are… suitable materials.

As mentioned, at the entrance and exit of the reference chamber 1, an inert and semi-permeable passage membrane 7 is placed which allows the preferential passage of certain substances over others. The membrane can be made, for example, of sulfurone polyester (PES) material. The membrane 7 has several functions: - Retain the suspended solids in excess (they can interfere with the fluorimeter). - Stabilize the water flow so that it is the same in both chambers.

- Avoid rapid colonization of the biofilm by resistant species to maintain a sensitive biofilm for longer.

- Ensure a low flow of water through the purifying filter 8 to ensure the efficiency of pollutant removal.

The water entering the reference chamber 1 is purified with activated carbon or a material with similar characteristics. Polar organic pollutants, generally with an octanol-water partition coefficient, KOW <3, and heavy metals are retained.

The octanol-water partition coefficient of a substance, also called the partition coefficient (POW), is the quotient or ratio between the concentrations of this substance in a two-phase mixture formed by two immiscible solvents in

BL-5222 LU500009 balances: n-octanol and water. This coefficient therefore measures the differential solubility of a solute in these two solvents. N-octanol was chosen because it is an organic compound that simulates lipid material well in biota, or in organic particles and organic sediments. This coefficient gives an idea of the hydrophobic character of a substance or the lipid affinity of a substance dissolved in water.

It should be taken into account that the purifying filter 8 does not contain substances harmful to the biofilm, for example, a biological filter with bacteria would be inappropriate because it could alter the biofilm. It must allow the flow of water, for example, with ultrafiltration membranes it would be necessary to install a pump to allow the flow of water. Preferably, it is inexpensive, easily replaceable and reusable. For all of the above, activated carbon is a good choice, it is heat reactivatable and reusable.

In addition, it is desirable that it be a homogeneous material to prevent water accumulation in one area of the filter, and that it reaches the entire volume of the filter homogeneously. One possibility is that it is grainy because it is less opposed to the flow of water.

On the other hand, in the monitoring chamber 2, the water, after having passed through the passage membrane 7, reaches an inert filter 9 made of glass wool or of similar characteristics. In this case, the inert filter 9 must not react with organic or polar pollutants (KOW <3) or with heavy metals, but it must meet the rest of the characteristics mentioned above for the purifying filter 8.

The hydrodynamic design of the two chambers 1, 2 must ensure adequate retention of pollutants. For example, a cylindrical shape ensures a uniform distribution of the water flow that passes through the filters. Since biofilm 5 is a living microbial community with regenerative capacity, it requires little maintenance.

To improve the efficiency of the device, it is recommended that Biofilm 5 be grown in a clean location and then transferred to the device. In this way, it is easier for the most sensitive species to be present.

The design of the device 30 must allow relative isolation of the biofilm within the reference chamber 1 and the monitoring chamber 2, which minimizes the colonization of resistant species through passage membranes 7 at the entrance and at the exit of the two bedrooms. A balance is sought which slows down colonization

BL-5222 LU500009 by resistant species without completely isolating the biofim 5 to maintain water flow. The extracts from passive sensors 3, 4 can be analyzed for a better determination of the quality and characteristics of the water. In this way, it is also possible to ensure not only a better identification of the pollutants but also the correct functioning of the filters 8, 9. In a versatile manner, the properties of the filters 8, 9 can be chosen to specifically suit the conditions. of the water to be analyzed. Typically, the life of a filter varies from two weeks to several months, depending on the quality of the water.

Figure 3 is an example of an exploded view of a possible monitoring chamber 2 coupled to electronic means for acquiring, transmitting and processing information from said monitoring chamber. Although not shown in this figure, the reference chamber would also be coupled to said electronic means. In the monitoring chamber 2, one can see how several biofilms 5 are housed in a housing module 10 which is inside the chamber and is made of PMMA. In this embodiment, the filter 9 has an associated tubular (containment) structure which defines a smaller interior chamber of PMMA or other material with similar characteristics. The housing module 10 is easily removable from one end of the chamber 1, 2 and is made of PMMA. To fix the elements, screws 27 (rivets or the like) made of PTFE are used on a closure 17. In this example, the housing module 10 has the capacity to accommodate up to five biofilms 5. The construction guarantees the lighting. , essential for the growth of biofim 5. All the materials used in the assembly of the device (PMMA, PTFE and stainless steel) are resistant and inert. Thanks to the inert filter 9, nutrients and possibly micropollutants penetrate. To ensure correct illumination of the biofilm 5, it is necessary to maintain an orientation of the housing module 10 towards the surface. For this, the distribution of masses is - carried out in chamber 2, or an additional structure which guarantees this orientation can be used, such as a ballast, a counterweight, moorings, etc. Regarding the elimination of the disturbance of suspended sediments of more than 0.1-0.2 μm and to limit the colonization of the biofilm 5 by resistant species, passage membranes 7 are put in place, for example, which are semi-permeable and

BL-5222 LU500009 hydrophilic polyethersulfone (PES) microporous, with porosity 0.1-0.2 um, on PMMA 17 supports with 27 stainless steel screws at the inlet and outlet of chambers 1, 2.

The placement of passive sensors 3, 4 should maximize the exposure of the sorbent surface. The biofilm 5 and the fluorimeter 6 are placed immediately after the filters 8, 9 ensuring contact of the biofilm 5 with any micropollutants present in the aquatic environment. In addition, the biofilm 5, which is exposed to light, is placed about 2-3 mm from the fluorimeter 6 ensuring a correct reading of the fluorescence signals. The tube-shaped chamber design provides good hydrodynamics and filter efficiency.

See values obtained experimentally: 2.8-7.4 ml / min / cm? at 0.7 bar, 10 µs with a 0.1 µm semi-permeable PES passage membrane 7; 19.3-34.6 ml / min / cm? at 0.7 bar, 10 ps with a 0.2 µm semi-permeable PES passage membrane 7.

It has been found that these values allow the growth as well as the accumulation of micropollutants in the biofilm 5, accumulation of pollutants also in the passive sensors 4, 5.

Although the material of construction is very strong, it may be advisable in some environments to place the two chambers 1, 2 inside a protective stainless steel cage. The cage can be used to maintain the proper orientation so that the light reaches the biofilm 5. Also to prevent theft or impact of stones that the current brings.

Regarding electronic means, there are many solutions for collecting and processing data from measurements. One possibility for transmitting data from the two passive sensors 4, 5 is to do so via a submarine cable 16 (RS-485 / S) which leaves the device through a small exit hole 14 in each chamber 1, 2 until to a data acquisition unit 18 with impermeable coating. The data can be saved in a storage memory, for example an internal ring buffer and a non-removable microSD card. The data acquisition unit 18 is connected via a water resistant cable 16 (RS-485 / S) to the surface equipment 19, located out of the water and powered by a production system. energy 26, preferably renewable, consisting of one or two solar panels, or, in places little exposed to sunlight, by a submerged hydraulic turbine which

BL-5222 LU500009 converts water energy into mechanical energy plus a hydroelectric generator that converts this mechanical energy into electricity.

It is possible to define a monitoring system which includes one or more devices 30 for an integral management of the water monitoring in different places. Each surface equipment 19 is responsible for transmitting data to a fixed destination, for example, virtually to a server in the cloud 20 by means of a transmission unit 23 which may be a telephone or satellite modem with Wi-Fi technology or similar. The data stored in the cloud 20 can be accessed and analyzed in turn from a remote computer 21 which, in the event of a significant difference in measurements between the two chambers 1, 2, can program the automatic sending of a warning signal 24 to a group of recipients. For example, the alert can be transmitted to the surveillance personnel via one or more surveillance terminals 22. The surveillance terminal 22 can be, for example, a smartphone with a mobile application or a computer, a tablet, etc.

Various useful functionalities can be added, for example the control of the sensors or the reading recorded by them. For example, in the case of the fluorimeter 6, control software can be installed to perform pulse saturation analysis and the calculation of standard fluorescence parameters. It is possible to define the execution of easily programmable custom experimental procedures using batch files. Data export in CSV (Comma Separated Values) format can also be implemented to record original fluorescence traces, saturated pulse data, and parameter estimates from light response curves.

Integrated passive sensors 3, 4 capable of accumulating organic compounds such as pesticides, pharmaceuticals and heavy metals can be recovered and the extracts can be analyzed in the laboratory, with techniques of chromatography and mass spectrophotometry, face to a significant change detected in the biofilm 5. This would be the mode of action in a pollution episode. The adsorbents can be extracted and analyzed, providing valuable information, for example, to identify the possible responsible for the toxic effects recorded in the biofilm.

Claims (13)

BL-5222 LU500009 CLAIMS 1. Device (1) for monitoring toxic substances in water, characterized in that it comprises: a first reference chamber (1) comprising a purification filter (8) and a second monitoring chamber (2) comprising an inert filter (9), wherein the two chambers (1, 2) are submersible and each further comprises: an inlet and an outlet for the flow of water; a housing module (10) configured to house at least one biofilm (5); a fluorimeter (6) configured to measure the fluorescence of the biofilm (5); where the two chambers (1, 2) are configured to allow, during use, the housing module (10) to receive external light; wherein the device (1) further comprises a data acquisition unit (18) configured to acquire the fluorescence measurement from the fluorimeter (6) of each chamber (1, 2). 2. Device (1) according to claim 1, further comprising a passive sensor for organic pollutants (3). 3. Device (1) according to claim 1 or 2, further comprising a passive sensor for inorganic pollutants (4). 4. Device (1) according to any one of the preceding claims, comprising a passage membrane (7) at the inlet and at the outlet of the chamber (1, 2) for the flow of water, where the passage membrane (7) is inert and semi-permeable. 5. Device (1) according to claim 4, wherein the passage membrane (7) comprises PES. BL-5222 LU500009 6. Device (1) according to any one of the preceding claims, wherein the purification filter (8) comprises activated carbon. 7. Device (1) according to claim 6, wherein the activated carbon is granular. 8. Device (1) according to any one of the preceding claims, wherein the inert filter (9) comprises glass wool. 9. Device (1) according to any one of the preceding claims, where the measurement of fluorescence comprises at least one of the following parameters: - basal fluorescence: - photosynthetic efficiency, YII; - regulated non-photochemical attenuation, Y (NPQ); - unregulated non-photochemical attenuation, Y (NO); - OR a combination of these. 10. Device (1) according to any one of the preceding claims, wherein the purification filter (8) and / or the inert filter (9) are installed inside a smaller interior chamber. 11. Device (1) according to any one of the preceding claims, further comprising surface equipment (19) configured to collect and transmit the measurements acquired by the data acquisition unit (18). 12. Device (1) according to any one of the preceding claims, wherein the surface equipment (19) comprises a wireless communication unit (23). 13. System for monitoring toxic substances in water, characterized in that it comprises: a device (30) according to claim 11 or 12; BL-5222 LU500009 a remote computer (21) configured to communicate with the device (30) and to compare the measurements acquired in the two chambers (1, 2), where the remote computer (21) is further configured to send a alarm to one or more monitoring terminals (22) depending on the result of the comparison.