Marcel Zevenbergen: “Internet of Water Flanders – IoW Flanders – is a collaboration between imec, VITO, the Flanders Knowledge Center for Water (VLAKWA), the Flanders Environment Agency (VMM), De Watergroep and Aquafin, with the support of Flanders Innovation & Entrepreneurship (VLAIO). It is a four-year project aimed at making Flanders a forerunner in the measuring and monitoring of various aspects of water quality. To achieve that aim, the project has set itself the goal of rolling out a more extensive and denser measuring network capable, for example, of transmitting the very latest data every fifteen minutes. Soon, sensors all over Flanders will be measuring a number of basic water quality parameters in groundwater and surface water. This network of sensors will by supplemented with other technology, including for data transfer, predictive models and IoT platforms. Plus the processes required for installation and maintenance. But in the first instance, the focus will be on measuring the level of salinization and discharges in surface water.”

How is imec involved?
Marcel Zevenbergen: “Imec is developing sensors that can be used specifically for IoW Flanders. In theory, the consortium is free to use whatever type of sensors it wants. But the ones that are currently on the market have two major drawbacks, even though they are very reliable. To begin with, they are more expensive to buy than the price we can make them for ourselves. And, second, we can add specific functions to our own sensors that are not always included in commercially available solutions. For example, it is virtually impossible to find an affordable sensor capable of measuring nitrate levels in water over an extended period of time, which is one of the main aims of the project. This means that the consortium had two particular reasons – cost and functionality – to move into the development of its own sensors. In other words, we have taken on the challenge of building a product that doesn’t yet exist, but which also has to be sufficiently robust. Imec has to develop the sensors to the point where one or more commercial parties can produce them in sufficient numbers and then implement and manage them.”

So they haven’t been developed to that stage yet?
Marcel Zevenbergen: “No. Imec is a research center, so our prototype sensors are not yet operating with the parts and production processes that are required to manufacture large quantities. For instance, it may be that we are still using mains power for our prototypes in the lab, whereas the final sensor will have to operate using a battery. Or we are assembling a small number of sensors manually, while ultimately they will have to be assembled on an industrial scale. This is why the project also includes a step for designing sensors that do actually meet the requirements for industrial production. One thing imec always does is to check whether the research is relevant: can it be applied on an industrial scale? Only when the sensor works properly will we proceed with producing larger quantities.”

But there’s a lot to consider when switching from research to production?
Marcel Zevenbergen: “There are two separate disciplines. The sensors we began this development process with are made from parts that are still in development themselves and which we usually only have a small number of. So we will use those to build a system that can operate under controlled conditions. We have already demonstrated with these prototype sensors that you can conduct readings in certain types of surface water for a period of several months. And that gave use the confidence we needed to embark on further development. The sensors used for the IoW Flanders project have to work totally independently for a long period of time in an uncontrolled environment. So it is logical that more robust components and assembly processes are needed. The installation also has to meet all of the requirements in terms of low power consumption, wireless communication, etc. And, finally, we have to check to see how the sensor performs in the ultimate application. In practice, the circumstances are extremely variable – even outside the limits of what we have tested previously.”

Can you give us a practical example of an unexpected challenge?
Marcel Zevenbergen: “There have already been two significant learning moments for us in the past year. The first was right at the beginning when we placed the first sensors in the water. One of the connectors that we had bought in from outside appeared not to be as waterproof at greater depths over the longer term as the manufacturer had claimed in its specifications. The second unforeseen complication occurred about six months later. On that occasion, it was the cable from the sensor to the transmission station that was causing electrical interference and disrupting the readings taken by the sensor.”

But these sound like simple problems to solve…
Marcel Zevenbergen: “It’s not as easy as it sounds. Sometimes it takes a while to find the right solution. For the ‘leaking’ connector we installed a water column five meters (see picture below) deep in our laboratory to test the connectors. Would they stay waterproof over lengthy periods at this depth? And it took us ages and a lengthy investigation to solve the problem with the cable. We could only see a discrepancy in the reading and had no idea where it came from. So we had to investigate a great many parameters: the sensor itself, the environment it was placed in, the peripheral equipment – and so on. In the end it turned out that the cable was producing a small electrical signal. That, combined with the setting of our sensor and the salt concentrations in the water, was causing problems. Now we connect the cable differently with the sensor module and that appears to have solved the interference issue.