Influence of input streams on the construction and demolition waste (CDW) recycling performance of basic and advanced treatment plants

The most common method of handling construction and demolition waste (CDW) is recycling; this produces recycled aggregates that can replace natural aggregates in various applications while offering social, economic, and environmental benefits. However, from technological, environmental, and management perspectives, CDW recycling faces complicated issues that require resolution. This study proposes a methodology for investigating the influence of segregation and heterogeneity of the inlet CDW stream, and the technological level of the recycling facilities, on the quantity and composition of aggregated product streams. Four different scenarios with the combination of two different segregation levels and two homogeneity grades of CDW were developed; two recycling plants of different technological levels, basic and advanced, were used to treat the CDW in these scenarios. The two segregation levels represent the actual situation and the future situation in Spain; the two homogeneity levels represent the mixing of different types of waste due to the contamination of the fractions. The results obtained indicate that under low segregation levels, basic recycling plants can reach the minimum target of non-hazardous CDW resource recovery set at 70% before 2021 by the European Union, as backfilling is permitted. However, high segregation levels and advanced CDW recycling plants are required if backfilling is excluded since the recycling percentage is much lower than the resource recovery percentage.