As part of the Emscher restoration project to return the river to a near-natural state and the construction of a massive underground sewer, numerous small wastewater treatment plants along the river were decommissioned in the 1990s. This included, in 1997, the plant in the Bottrop-Ebel district, where the Berne River flows into the Emscher. It was to be preserved not only as an industrial monument but also redesigned with a new function as a park offering a pleasant environment, particularly for local residents.

Garden artist Piet Oudolf, in collaboration with landscape architects GROSS.MAX, realized the project “Theater of Plants.” The concept is based on the repurposing of the two former circular settling basins. While one remains filled with water, Oudolf and GROSS.MAX designed a walk-in sunken garden for the other.