Bekkelaget Sewage Treatment Plant

The Bekkelaget Sewage Treatment Plant was commissioned in 2001. It is the second biggest biological treatment plant in Norway, removing nitrogen compounds from the sewage. It treats sewage generated by 290 thousand inhabitants of the eastern part of Oslo, and also partially from the communes of Oppegård and Nittedal. Its operation is crucial to the cleanliness of the water of Indre Oslofjord (internal part of the fjord) and makes it suitable for swimming, fishing and sailing. The treatment plant filters around 42 million cubic meters of sewage a year.

The vast halls with sedimentation tanks operate Arne Nordheim’s sound installation Dråpen [A drop]. It is an example of art being located in contexts which are unexpected for the majority of spectators or listeners.

The music takes the form of a mass of individual files recorded on a hard disc – fragments of sounds and tones – and a control program, which selects individual files. The control program responds to the amount of sewage flowing down to the treatment system and selects the sound material and the density of the sound according to the signal it receives from the control panel of the treatment plant. The installation is equipped with 21 speakers, and the sounds travel from one speaker to another in accordance with pre-planned patterns, but they mix also with the mechanical sounds of the plant and those accompanying the sewage treatment process.

Nordheim spoke of Dråpen:

"Somewhere within that mountain we should arrange a meeting of technology with humanity. The goal is to introduce the visitors to the function of the place and allow the elements of the cleaning process to define the sound effect. I imagine that drop-like sounds could tell some stories about the immense volumes of liquids which carry on their obscure life under the Ekeberg mountain. The sound may give visitors some idea about the distances and tangibility of the surrounding rock and water."

Sigurd Saue created a simulated recording of the sound of Nordheim’s installation in the sewage treatment plant.