Construction and demolition waste constitutes a large fraction of all the waste generated in Europe. Its specific impact can be considered rather low, but the large generated volume and embodied resource makes this waste stream an important focus of current European policies. The European Commission has proposed new targets and goals for this waste stream in the Circular Economy package, but, given the rather heterogeneous landscape of waste management practice across Member States, new approaches that take into account the entire value chain of the construction sector are urgently required. This paper synthesises core principles and linked best practices for the management of construction and demolition waste across the entire construction value chain. Systematic implementation of these best practices could dramatically improve resource efficiency and reduce environmental impact by: reducing waste generation, minimising transport impacts, maximising re-use and recycling by improving the quality of secondary materials and optimising the environmental performance of treatment methods.

Introduction

Currently, the European construction sector produces 820 million tonnes (megagram, Mg, or 1000 kg) of construction and demolition waste (CDW) every year, which is around 46% of the total amount of total waste generated according to Eurostat (Eurostat, 2017). The average composition of CDW shows that up to 85% of the waste is concrete, ceramics and masonry, although CDW can be heterogeneous depending on the origin, and may contain large amounts of wood and plasterboard (Monier et al., 2011; U.S. Environmental Protection Agency, 1998). In any case, CDW inorganic fraction is frequently characterised as “inert” due to lack of chemical reactivity at ambient conditions. Most CDW consists of excavated materials, which are considered to have a low environmental impact upon disposal. If excavated materials are excluded, around 300 million Mg of CDW were generated in 2014 at European construction sites (i.e. EU 28 new construction, demolition or refurbishment activities). Construction and demolition waste is characterised by its high volume and weight but with probably the lowest environmental burden and the highest inert fraction per Mg of all waste streams. Although the specific environmental impact (per Mg) is low if compared with other waste streams, the associated environmental impacts of such a high amount of CDW is an important concern, mostly derived from its logistics and land occupation. Hence, the management of CDW constitutes a priority for most environmental programmes around the world, especially in Europe. In fact, the European Commission (European Commission, 2015a) has proposed that, by 2020, “the preparing for re-use, recycling and backfilling of non-hazardous construction and demolition waste excluding naturally occurring material defined in category 17 05 04” – i.e. soil (including excavated soil from contaminated sites) and stones not containing dangerous substances – “in the list of waste shall be increased to a minimum of 70% by weight”. Remarkably, the definition excludes naturally occurring materials but introduces overall recovery targets, while some experts have recommended to introduce separate targets per fraction and to revise the definition of treatment operations, as backfilling (Arm et al., 2014; BioIS, 2016). There is also some concern on the use of weight percentages, since waste managers may focus on the dense mineral fractions rather than on other fractions with potentially higher potential environmental impact (Arm et al., 2014).