International Review of Waste Management Policy - Department of ...

when comparing facilities which biologically treat waste prior to landfilling. This is the
case especially for climate change and eutrophication.
This is somewhat disappointing since climate change is one of the impact
assessment categories where there is relatively good agreement as to how the impact
of different emissions should be weighted. In many other impact assessment
categories, particularly those related to eco-toxicity, there are some more general
concerns about the weightings applied to different pollutants under different impact
assessment methods.
This problem is almost certainly exacerbated in WRATE because the model seeks to
be comprehensive in the range of pollutants which are covered. It is almost certainly
the case that the datasets which reside within the model derive from studies which
vary in the degree to which they seek to record all pollutants emitted. Similar sorts of
bias can occur, as demonstrated above, where the model builders seek to make good
for the absence of data on specific emissions with reference to other facilities.
62.3 Concluding Comment
The upshot of the above discussion is that:
976
� The model used by the STRIVE report suffers from some shortcomings which
tend to bias the assessment which was carried out. This is not to say this was
deliberate on the part of the authors. Rather, it makes the point that the model
has some serious limitations;
� The relative confidence with which the conclusions are drawn in the report is
perhaps misplaced.
Hence, the report’s statement that: 1194
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As can be seen from an examination of the charts, a waste management
scenario which includes a high energy recovery (i.e. recovery of both heat and
energy) thermal treatment performs consistently well over each of the impact
categories, performing best in each category. The mechanical biological
treatment scenarios and the low-energy recovery scenarios have varying
ranking over the impact categories.
Can be traced effectively to being a function of
� The operation of the model, and
� The choice of MBT system used in the modelling.
The study’s authors later state:
There is a need for further study into the emissions and environmental fate of
materials in MBT systems
1194 Fehily Timoney & Company / Veolia Environmental Services / Ramboll (2008) Critical Analysis of
the Potential for Mechanical Biological Treatment for Irish Waste Management: Volume 2, Research
Report, Report for the Environmental Protection Agency, September 2008.