Most water purification plants are devoid of personality, but that’s not so for the Swiss city of Muttenz’s new water treatment facility. Designed by international architectural firm Oppenheim Architecture, the Muttenz Water Purification Plant rejects the sterile stereotype and adopts a curving and organic form that looks as if the building was naturally sculpted out of the earth.

rust-colored water treatment building lit from within at night

Set within a lush green forest next to the river Rhine, the low-maintenance industrial plant not only sensitively and sustainably adapts to its natural surroundings, but also serves as a new city landmark that includes a public-facing area to educate the population about the facility’s three-phased, state-of-the-art water purification process.

interior of rust-colored water treatment building with raised walkways

The Muttenz Water Purification Plant is encased entirely with shotcrete, also known as sprayed concrete, which was delivered dry to the construction site and then mixed with water just before application. Shotcrete was selected because of the sensitive nature of the construction site in a drinking water protection zone.

water in a rust-colored water treatment building

The expressive and low-maintenance facade appears both soft in appearance yet hard in texture and allows rainwater to flow from the roof across the sides, which will gradually leave a natural patina and encourage the growth of moss over time to blend the building into the landscape.

Related: This moss can naturally eliminate arsenic from water

water reflections on rust-colored wall

“The engineering-driven arrangement of the inner life defines the form and the size of the building,” explained the architects, who noted that the water purification building is set between a protected forest and the nearby industrial parks. “Like a tight dress, the skin presses against it and represents the technical inner life to the outside. Pipelines, filters and apparatuses can be read through the facade in an abstract manner. The result is an expressive building, acting like a ‘objet trouvé’ in its natural context. Reduced to its materiality and form.”

close-up of water inside rust-colored water treatment building

To heighten the educational experience for the public, the water purification plant puts parts of its complex and its state-of-the-art technology on display. One example is the open, alcove-like presentation room that is open to the outdoors and allows visitors to experience water from multiple perspectives, from the cooling sensation of the surrounding pool to the sounds and sights of rainwater pouring in from the roof.

+ Oppenheim Architecture

Photography by Börje Müller via Oppenheim Architecture