Assessment of waste streams from building demolition in Vienna based on image-matching change detection

Major waste streams in urban areas result from the demolition of buildings. In case of lacking data on demolition waste generation at the regional level, the quantity and composition of demolition waste from buildings can be estimated by multiplying the volume of demolished buildings by their specific material intensities. Information about building demolition (number of demolished buildings, demolished building volume) based on statistical data or other official records are often incomplete. Hence, this paper presents an alternative approach for validating demolition statistics (number and volume of demolished buildings) and subsequently demolition waste generation by applying change detection based on image matching using the city of Vienna (Austria) as a case study. Based on this technique, building demolition activities not reported to statistical municipal departments can be identified. Results for 2013/14 show that in the city of Vienna, demolition statistics yield a total volume of 1.7 M m³/a demolished building volume, while change detection based on image matching yields a total volume of 2.8 M m³/a. Consequently, demolition waste generation figures solely based on statistical data would significantly underestimate the total waste generation. The presented approach is a useful tool for validating existing data on demolition waste generation and demolition statistics and can also be used when these data sets are not existent at all. Furthermore, the approach serves as a basis for continuous monitoring of the building stock and its dynamics. The latter is regarded as a prerequisite for the prognosis of material flows and for the promotion of a circular economy in the building sector.