categories calculated with EDIP are resource depletion, human toxicity
via water, air and soil, ecotoxicity in soil and water, stratospheric
ozone depletion, acidification, photochemical ozone
formation, and nutrient enrichment. The normalisation values
can be found in Laurent et al. (2011). For global warming the IPCC,
2007 characterisation factors were used (IPCC, 2007). To calculate
the environmental impact from the waste system we used a functional
unit consisting of the treatment of one tonne of household
waste.
3. Results
From the calculation methods used we obtain three types of results:
the first and second from the two methods for estimating total
impact (Cases 1 and 2), and the third from the comparison of
alternative waste management systems. Impact categories contributing
to savings less than 0.5% of one person’s annual average impact
are not included in the results. This leaves us with six impact
categories, of which human toxicity via water is the most important
due to replacement of virgin aluminium production.
3.1. Cases 1 and 2
Results from the systematic ±15% changes in the paper, plastic,
food, glass and metal content of the waste are shown in Fig. 3. All
results are given as the percentage change in total impact