This approach allows comparison of different waste composition data. However, waste composition data in percentages are closed datasets because the proportions of individual fractions are positive and add up to a constant of 100 (Filzmoser and Hron, 2008).
As such, these data require special treatment or transformation prior to statistical
analyses (Aitchison, 1994; Filzmoser and Hron, 2008; Reimann et al., 2008).