The drop is associated with three main causes: a) a decrease in renovation and improvement projects, reducing all types of waste generated in this activity (equipment with oil, oil, water-oil mixture and inert materials); b) a reduction in hydrocarbon-contaminated soils, due to a decrease in the number of accidents; c) a decrease in septic tank sludge, resulting from a change in its management (the content of the sealed tanks meets the parameters to be considered as wastewater, and can, therefore, be emptied into a treatment plant without being considered waste).