Environmental impact of demolition waste — An overview on 10 years of research and experience

Demolition waste is a major part of industrial waste. In general, demolition waste is heterogeneous and consists to a large extent of building materials but includes even small amounts of hazardous substances. Since the early 1980s the processing of building rubble has become more and more common in most industrialised countries. After appropriate processing the major part of these materials meet the technical properties for reuse. Increasing emphasis is being placed on the environment-related properties due to composition and origin. The results of standard leaching tests are discussed both regarding treatment technologies and different secondary building materials obtained. Generally, the effect of wet or dry processing is considered to be of subordinate importance to the environment-related properties of the main fraction. A comparison of more than 10 different treatment plants proves this statement. Only some 3–50% of this fraction is subjected to wet and dry processing. Even a significant difference between portable and stationary plants could not be ascertained. Inorganic compounds dominate the leachate composition due mainly to the mineral matter in demolition wastes. However, organics, e.g. phenols, PAH, PCB and halogenated compounds, are detected in some cases. The leachability of sulphate, heavy metals (Ni, Pb), and phenols as well as the solid content of EOX, PAH and CH might restrict an unlimited application. Compared to the research carried out earlier, the environment-related properties of leachate from demolition waste are now less important. In fact, the influence of waste treatment is of minor significance whereas the pre-treatment or pre-selection is more important to the operators of demolition recycling plants. According to the change in waste composition and tighter specifications the treatment process and demolition techniques must be optimised.