One of the objectives of this project was to lay out the courtyard as a regulating and organisational element, a space drilled into the solid volume, completing the available geometry. From outside, the building looks like a hermetic, abstract box exhibiting the entry area through a drilled hole, another space. The structure of the upper floor is developed around the space, a courtyard formed of concrete walls and sheets of glass, overlooked by the offices and the control room. These are organised in a comb-scheme with prongs for parallel circulation to the courtyard, where administrative and control tasks are located. The proximity to the sludge treatment plant and the heavy level of lorry traffic make protecting the work areas and qualifying them through large open skylights on the roof a necessity. These industrial constructions must be large but low-cost, so we chose an austere design that makes a feature out of large concrete walls and lean, precise lines, eliminating the superfluous and the unimportant.