An assessment of the illegal dumping of construction and demolition waste

Addressing the illegal dumping of construction and demolition waste (CDW) is challenging because there are significant costs associated with clean-up actions but, for many local authorities, no data is available to describe this reality and to support the decision-making process. This research is focused on how to study the dynamic of CDW dumpsites, characterising these occurrences in order to understand the factors that influence them and to raise awareness to the problem with the results obtained. It involved the municipalities of a rural region, with scant infrastructure for CDW treatment, in monthly observations of the aforementioned sites. In total, 136 dumpsites were observed, with 65% of them located on public-owned land. For these dumpsites, 18 thousand tonnes of CDW were estimated, of which 59% correspond to the mineral fraction. The cost of removing the abandoned CDW was estimated at between €84 and €99 per tonne, with the component directly associated with municipal resources estimated at around 28% of the total. During the one-year monitoring period, 26 new dumpsites were observed, and 156 tonnes per month of CDW were recorded. Performance indicators demonstrated that the municipalities with some type of local solution for CDW management report less illegal dumping. These findings are relevant for filling the gaps in data about the illegal dumping of CDW on local scales and in less developed countries, supporting decision-making processes. In terms of research, the results address gaps in the literature since there is scarce data about these occurrences.