My Internship Journey at Hölscher Jensen

My name is Svenja, I come from Karlsruhe in southern Germany, and I am an environmental engineer with a particular interest in water treatment. From January until the end of July, I completed an internship at Hölscher Jensen in Denmark. During these seven months, I gained valuable experience in PFAS treatment, pilot testing and project management while learning how rewarding it can be to work independently as part of a supportive team.

My interest in water treatment began during my bachelor’s degree in Environmental and Construction Engineering. In my practical semester, I gained my first insights into the field and was fascinated by how chemical, physical and biological processes can directly improve people’s quality of life. After all, clean water is one of the foundations of life.
After my bachelor’s degree, I completed an internship at Tjaden in the Netherlands, where I first came into contact with the Hölscher Group. I later earned a master’s degree in Environmental and Process Engineering and focused on PFAS treatment methods in my master’s thesis. Because PFAS is a major environmental challenge worldwide, I wanted to gain more practical experience and contribute to finding suitable treatment solutions.

When I applied to Hölscher Jensen and suggested carrying out pilot studies on PFAS treatment, the idea immediately caught their interest. It quickly became clear that the internship would be a great match.
One of my main responsibilities was researching different PFAS treatment technologies, comparing their advantages and limitations and assessing whether they could be suitable for Hölscher Jensen’s projects. Unfortunately, there is no magic button that simply makes PFAS disappear, although that would certainly make the job easier.
I was also involved in planning, conducting and evaluating several pilot trials. Working with the pilot plants was one of the highlights of my internship because it allowed me to connect theory with hands-on experience. It is one thing to read about a treatment method in a scientific paper. It is another thing entirely to stand next to a pilot plant, adjust operating parameters and find out whether the system behaves as expected. Pilot plants tend to have their own personality and they do not always care about the plan you prepared in advance.

The practical work helped me understand how treatment technologies perform outside the laboratory and what must be considered when transferring an idea into a real project. I was given a great deal of freedom in organising my work, which meant setting priorities, coordinating tasks and making decisions based on the available information. This strengthened both my project management skills and my sense of responsibility.
I was also included in Hölscher Jensen’s main Nordhavn Tunnel project. This created a good balance between working independently and collaborating with colleagues. I appreciated being trusted with my own responsibilities while always having access to the team’s knowledge and support.
Working in Denmark was another valuable international experience after my internship in the Netherlands. Living and working abroad encourages you to leave familiar routines behind, adapt to a new environment and communicate across cultural and professional boundaries. It also teaches you that technical discussions work surprisingly well across borders.

From October, I will join Hölscher as a trainee at the Karlsruhe-Ettlingen location. My long-term goal is to work in construction and site management, and the trainee programme will give me experience in both dewatering and environmental engineering.
Although my internship in Denmark has ended, the pilot trials are still ongoing. I hope to remain involved and continue collaborating with my colleagues at Hölscher Jensen. PFAS treatment will also remain an important subject for me, as many questions still need to be answered before efficient and sustainable solutions can be implemented on a larger scale.