Shaila Sijstermans

Vacancy in industrial heritage sites is becoming increasingly common, which is why this graduation project proposes the adaptive reuse of the former wastewater treatment plant in Heerlen as a spa resort. The design integrates the history of the site, translating its original function of water purification into a process of cleansing and relaxation for visitors. The act of kuren — therapeutic bathing and treatment — forms the most significant societal aspect of the design.

The design contributes to ecological sustainability through the redevelopment of landscape elements, such as allowing the Geleenbeek to meander again and enhancing biodiversity by removing exotic tree species. These two landscape interventions increase the ecological value of the site and transform it into a more open and natural environment.

The Geleenbeek, which runs alongside the site, provides a key connection to the theme of building with water. Water functions as a purifying element and is used both within the adaptive reuse and in the surrounding landscape to complete the visitor’s experience.

Central to the design is the visitor’s route and the corresponding sequence of spaces. These include a changing room, a footbath, saunas, pools, a relaxation space and a restaurant. They are integrated into the existing industrial structures of the wastewater treatment plant, where the robust concrete forms are combined with new, more refined materials that function as a new purifying layer placed over the former facility. Circular construction plays a crucial role in the transformation: existing structures are preserved and upgraded through the programme of the spa resort.

The design also highlights the former functions of the site and informs visitors about how the installations once operated. The spatial forms in the design are derived from existing shapes or processes of the original machinery, allowing the area to read as a coherent whole even though the structures lie separately and dispersed across the site. The landscape route is constructed as a suspended walkway using timber decking, and the circulation through the tanks (which now house the saunas) is also made of wood. This allows the felled exotic trees to be reused on-site, further reinforcing the project’s circular ambitions.

The thesis includes research on the site, the morphology of wellness reference projects, relaxation rituals in other cultures and the functioning of the former installations at the wastewater treatment plant. The design decisions made do not only result in an enhancement of the site itself, but also have an impact far beyond it, and the thesis further investigates how the project influences the surrounding environment.

The transformation of the wastewater treatment plant into a spa resort serves as an inspiration for future industrial redevelopments. The well-integrated design supports the preservation of historical value while offering the possibility to revitalise an abandoned industrial site, with a strong focus on ecological sustainability and human wellbeing. In addition, the project contributes to the improvement of the Parkstad region by establishing connections between surrounding valuable natural areas and functioning as a node between them.