municipal waste and some general conclusions can be transferred to other environments given that the specific
assumptions and parameters are taken into account.
3.5.5 Data gaps/further research......................................................................................
Key parameters
Most studies give very precise information about the energy mixes used for waste management processes or for
avoided processes. When examining the issues of carbon storage and binding, the uncertainty of the processes
involved is mentioned but the values and processes used for the impact assessment are mentioned in only one
out of five studies that take carbon binding into account. In order to better understand and evaluate the
mechanisms and functions simulated in each study, there is a need for further transparency of assumptions. On
the other hand, the description of technologies used as well as their efficiencies is quite extensive and well
documented.
Coverage of the various end-of-life alternatives
The selected studies for this report focus mainly on comparisons among the traditional municipal waste treatment
options (landfill, incineration, composting). Some variants within these traditional options are explored, such as
home composting, central composting and landfill, with or without energy recovery. Anaerobic digestion, which is
being developed rapidly, was also examined and presents quite optimistic results in most impact categories when
compared to other options. However, this alternative has not been properly tested in different local conditions
and a sensitivity analysis for different operational conditions would be necessary in order to test the viability of
this option. The data requirements to ensure the quality of the study make it difficult to conduct LCAs on
upcoming options that are still at the experimental stage.
Environmental indicators
The current trend to prioritise global warming as an environmental indicator is illustrated in the selected LCA
studies. All examined reports include climate change in their range of addressed impact categories. Primary
energy demand, eutrophication, acidification and photochemical oxidation are the most popular indicators, while
the rest of the indicators are included in a maximum of two studies.
Two of the priority indicators according to the scope of this report, depletion of resources and water
consumption, were each investigated by one study each only. The individual scope of each LCA meant that the
reports could not provide a more comprehensive picture for the environmental implications of organic waste life
cycle. In particular, specific impacts such as the depletion of groundwater resources to landfill and compost were
poorly addressed. On the other hand, all toxicity and ecotoxicity impact categories calculations possess an inherit
uncertainty, which renders the impact assessment relatively unreliable. Therefore, until more solid assumptions
and impact potential factors are assessed, many reports will appear hesitant in including a complete toxicity
analysis.