The new solution for measuring wastewater developed by the students.

Students develop new method to measure wastewater

Tuesday 30 Jun 20


David Juul Ørnsholt


Ole Larsen
+45 27 95 42 60

A group of DTU students has developed a simple solution to measure how much rainwater flows into sewers from roads and roofs. Now they are getting ready to start a business based on their idea.

In recent years, the water sector has become increasingly digital. However, a prerequisite for this is that the necessary data are available, which is not yet the case in all areas—e.g. there is a lack of knowledge about how much rainwater is diverted from roofs and roads into sewers, which is an important prerequisite for better wastewater management.

A solution to obtain these data in a simple and inexpensive way was therefore one of the tasks of this year’s X-Tech Entrepreneurship at DTU—a 13-week course for students where they are given a range of innovation tools they can use either to start their own business or to handle development tasks in their future jobs. The tasks at X-Tech Entrepreneurship are largely set by companies, and in the spring, one of the tasks came from the innovation network CALL Copenhagen, which works with climate adaptation in the water field.

“At the moment we don’t have data on the amount of rainwater that enters the sewer system, which can be subject to a high degree of local variability. It was therefore interesting for us to test whether the students could propose new ideas for a simple and inexpensive solution that can obtain these data,” says Project Manager Ole Larsen, CALL Copenhagen.

Simple solution
The challenge was taken up by one of the participating student groups which created a solution in the form of a vessel installed at the sewer system’s rainwater inlet—e.g. under one of the many street grates. When the vessel is full, it tips so that the water can drain out and the amount of rainwater is then recorded.

“We’ve developed the solution in cooperation with a few wastewater companies. Part of the solution therefore comprises components that already exist, while we have developed other parts ourselves,” says David Juul Ørnsholt—one of the students behind the project.

At the final of X-Tech Entrepreneurship, the group received a price of DKK 25,000 for the best ‘Tech Demo’. The next goal is to be selected for Venture Cup, where students hope to hone their business idea further.

“Our group originally consisted of a total of six students from very different academic backgrounds. However, only two of us will continue to work and create a start-up based on the meter we have developed,” says David Juul Ørnsholt. The other student is Sebastian Hoppe.

Pilot project as start-up basis
The two students and Ole Larsen from CALL Copenhagen have succeeded in establishing an initial pilot project to test the new meter. This is being done in cooperation with HOFOR and Frederiksberg Forsyning. The project includes the installation of meters in some of the rainbeds built in recent years as part of climate adaptation efforts. Here, the meters will have to provide data on how much rainwater enters the beds and what proportion of the water subsequently flows out.

“Rainwater beds are constructed using a fascine, which over time becomes filled with clay and therefore needs to be cleaned regularly. At the moment, this is carried out on the basis of an estimate, but the pilot project will create valuable knowledge about whether it is necessary to clean once a year, for example, or whether in fact it can be done once every five years,” says Ole Larsen.

For the two students, David Juul Ørnsholt and Sebastian Hoppe, their summer holidays are on hold. Instead, the time will be used to further develop their idea for a rainwater meter and produce the number of prototypes to be used in the pilot project. In addition, the two DTU students will spend time finding a third member for their start-up—someone with business as their field of expertise.

“In the X-Tech Entrepreneurship process, it became clear to us that we didn’t have the necessary business competences. The participating students from CBS, for example, had a completely different grasp of the subject—something we need to add our company,” says David Juul Ørnsholt.

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