Based on the conducted LCA study, the results give a strong
indication that for the aeration compressor, the additional material
needed in the diffuser manufacturing has an insignificant influence
on the total greenhouse gas emissions. It is also shown, that selecting
the diffuser design has a large influence on the resulting greenhouse
gas emissions for the studied case. However, when choosing
an aeration compressor it is important to evaluate the range of the
required operating map and study whether there is a risk of operating
close to the choke and surge limits. Although this may
exclude especially the use of vaned diffuser in some cases, the
use of a pinch or low solidity vaned diffuser will be in the scope
of most of the waste water treatment plants due to their wide
operating maps.