The first project designed by Edouard François and Duncan Lewis during their collaboration from 1994 to 1997 was the School in Thiais, near Paris. The winners of four competitions, they developed their practice by taking on both large—and small-scale projects, like the tunnels and trenches for the A20 highway, several multi-unit housing projects and the Water treatment plant in Nantes. For the latter project they opted to completely reorganize the site for the sewage treatment plant of Fougas, spread over 95 hectares, agreeing to tackle the processes of removing contaminants from waste water, water treatment, economics and technical control. The project is oriented along an east/west axis in both the real and symbolic movement of the transformation of waste to clear water: first the technical buildings (floaters, basins, and aerator), then the administrative buildings and laboratories, and finally the lagoons. At the far western end, woods and high grasses grow in a landscape irrigated with purified water, thereby turning the former discharge into a green space. Three processes are literally on display along this trajectory: murky sewer water is cleaned and purified; nature, sparse around the technical buildings, becomes increasingly luxurious towards the opposite end; the mineral slate covering gives way to a vegetal landscape. Species of high grasses invade the site, demonstrating the fertility of reclaimed soil where formerly there was no vegetation. Inspired by the theme of mutation, the basins are gradually covered with plants: to the east, they are faced with a stone skin composed of gabions of slate, while the next stage, the clarifier, is covered with greenery. The technical buildings standing on ground composed of slate are girdled with trees, through which the poured concrete forms hint at the animated processes within. All the technology is subordinated to a desire to qualify the skin of the walls and to imbue the buildings with a sensitive, modifiable and tactile appearance of motion, with the aim of concentrating all the dreamlike qualities of the landscape. Even the seemingly random placement of the basins makes them look like the banks and tufts of lagoons.