Technical analysis of full-scale Construction and Demolition Waste treatment plants: case studies of the Lombardy Region, Italy

Construction and demolition activities in Italy and the Lombardy Region produce a considerable amount of wastes that can be valorised as secondary raw materials. The recovery of construction and demolition wastes is severely limited by the lack of consolidated and sustainable treatment chains and by the strong variability of their environmental characteristics that may generate potentially dangerous effects for the environment. The purpose of this study was to evaluate and technically define the current treatment chains in the Province of Brescia (Lombardy) by analyzing three full-scale treatment plants in order to highlight barriers to demolition waste recovery and propose possible solutions and improvement strategies. To best represent the entire management and treatment system, the analysis was developed on all the acceptance, treatment, and final quality control phases. Moreover, chemical composition and leaching data on demolition wastes and recycled aggregates were collected from the three treatment plants and statistically analyzed to assess their potential recovery according to the Italian legislation. Mixed non-hazardous waste is the fraction mostly managed by recycling plants and mixed recycled aggregates are the main products obtained from the treatment. These are mostly used in roads and in geotechnical applications. Chemical composition results showed that the pH is generally alkaline and tin and benzene are the most critical elements for both demolition wastes and recycled aggregates with respect to the regulatory limit values. Total chromium was identified as a critical compound in leachates. The results of the statistical analysis confirmed that chromium was mainly released by cement materials.