On a roughly 26-acre site where lignite was once mined, an environmental theme park has been created, comprising various landscaped areas and a number of pavilions. The “Waterworks” pavilion demonstrates the purification of water by a so-called “living machine”. After initial anaerobic treatment, waste water from the site is fed through a series of tanks along the length of the pavilion, where it is purified by water plants until it achieves drinking-water quality. The pavilion has a clear, simple structure. The steel skeleton frame stands on the concrete cross-walls that form the divisions between the tanks. The lightweight ETFE membrane cushions to the facade and roof facilitate a slenderly dimensioned structure and high UV transmission.