ToxMate, a technological breakthrough from ViewPoint, marks a turning point in the instant detection of micropollutants in treated water from urban and industrial wastewater treatment plants and drinking water treatment plants. A highlight of the measuring system is its remarkably precise temperature control, the result of a close collaboration with SMC.
But what is the current standard process? Water treatment plant managers regularly take water samples, which are then sent for physicochemical analysis. This system has a number of drawbacks. Firstly, these targeted analyses can only detect a limited selection of micropollutants. In addition, they are subject to long delays, as they are not carried out continuously, and sometimes require several days, or even weeks, to obtain results. The cost of these analyses is also a significant obstacle. This lack of responsiveness is a serious issue: not only are anomalies detected only after a considerable lapse of time, but they also concern only a limited number of micropollutants. It is important to note that water from sources such as rivers or groundwater can contain a wide variety of micropollutants. Sometimes, the combination of these substances can result in a cocktail effect, leading to the formation of even more harmful compounds
A revolution in water quality assessment with ToxMate
In the sphere of micropollutant detection, ToxMate represent a real revolution. So, how does this remarkable innovation work? Taking its inspiration from nature, this invention is based on the observation that aquatic fauna is highly sensitive to human pollution. ToxMate analyses the behaviour of three species of aquatic invertebrates - gammarids, leeches and radix - which are naturally present in freshwater aquatic environments. Using a machine vision camera, the device analyses their behaviour in a continuous flow. As bio-indicators, these organisms reliably and effectively show the level of water pollution. On-site tests have demonstrated ToxMate's sensitivity to mixtures of substances, where conventional physicochemical sensors are limited to partial detection of the molecules present in the water. These invertebrates modify their behaviour, such as their position or movements, in response to the presence of micropollutants. One obvious example is if they swim away, but there are many others. ViewPoint has developed a detailed mapping of these behaviours, in relation to specific pollutants. Years of laboratory research, in collaboration with INRAE, and the use of ToxMate in a variety of environments have yielded a considerable amount of data. These data help to interpret the presence of many micropollutants in terms of the reactions of organisms.
Invertebrate behaviour analysed using vision cameras
From laboratory device to proven industrial equipment
From laboratory device to proven industrial equipment Today, ToxMate is used in urban and industrial wastewater treatment plants, as well as for drinking water purification. Frédéric Neuzeret, ViewPoint's Production Director, explains: "Our aim was to standardize analysis conditions. All parameters had to be completely identical if we were to correctly interpret the behaviour of aquatic invertebrates". A number of challenges had to be overcome, such as vision problems using infra-red light, and temperature control of the effluent under different sampling conditions.
ViewPoint implemented a solution with SMC to regulate the water temperature using a chiller with a tolerance of 0.2° degrees, for a flow rate of around 1l/minute. To ensure such precise regulation, it was not possible to measure the temperature simply at the tube exchanger, so it was decided to place probes in the basin to activate the chiller's power more appropriately and quickly. The temperature in a tank is stratified, and the probes enable more accurate temperature measurement for optimum control. Communication is via MODBUS on RS-485.
Technical innovations and close collaboration
Frédéric Neuzeret describes the technical background leading to their latest innovation: "To cool or heat the water pumped into the pools, we needed a chiller. After an in-depth analysis of the market, SMC's solution emerged as the best choice, not only for its unrivalled compactness, but also for its exceptional reliability. What really set SMC apart was their technical expertise and support in developing a tailor-made solution. The chiller's robustness proved to be a major asset, guaranteeing consistent, reliable performance.
In addition to these extremely important aspects, the collaboration with SMC focused on the design of a sophisticated and precise closed-loop temperature control system. A sophisticated closed-loop temperature control system was then developed. It is based on remote probes that indicate the energy required by the chiller. Pumped water passes through a serpentine tubular heat exchanger before reaching the test chamber, where it is analysed by machine vision cameras. SMC carried out the modelling and thermal calculations to design plastic prototypes and arrive at a perfectly stable solution. "SMC was very reactive. Especially when we needed an adaptation to the product, because the standard chiller used only internal sensors. SMC very quickly came up with a solution for connecting to external remote sensors," says Frédéric Neuzeret in conclusion.
The final element is the system's robustness to polluted water. Depending on the application, filtering may be necessary. Excessive filtering will produce partial results, while insufficient filtration may lead to clogging. The surfaces in contact with the water have also been adapted. One solution that worked was to use glass, but this was complex to manufacture. SMC therefore proposed a stainless-steel exchanger, reinforced with a layer of Teflon, as 316 stainless-steel alone was not sufficient, especially for metal residues.
