The operators of wastewater treatment plants with a capacity greater than 2,000 population equivalent units send an annual report to the Administration of the environment which includes, among other things, the quantities of sludge produced, the composition and characteristics of the sludge and the destination of the sludge.

The relatively quiet urban oases include public green areas and open spaces with a high quality of living space and an appropriate design as compensation areas within walking distance of residential and work locations. Due to their inner-city location, they do not, or do not completely, meet the above-mentioned criteria of a quiet area, e. g. by showing an increased noise level or being significantly lower. However, the urban planning context of the areas has noise-reducing properties, which lead to the fact that the urban oases in their core areas are considerably calmer than their surroundings. These areas make it possible, for example, to take short walks for those seeking peace and quietness in the immediate vicinity of their homes or workplaces.

The quiet areas in rural areas include large, cohesive and intact open spaces of supraregional importance with a high recreational function and corresponding development for leisure and recreation. These spacious areas allow for example extensive walks without crossing noisy areas.

The quiet urban landscape areas include relatively large, continuous open spaces of at least regional importance with a high recreational function and corresponding development for leisure and recreation. Its importance lies in the balancing function to the noisy and densely populated areas of the agglomeration of Luxembourg. The quiet urban landscape close to the residential area allows, for example, extensive walks with only occasional crossing of areas with higher noise levels.