Environmental Engineering Reference
In-Depth Information
Figure 6. Schematic of the compared integrated waste treatment scenarios.
Table 17 shows that the energy and environmental performances for scenario I and
scenario II are quite similar, even if the CO
2
emissions are higher in the case of MSW WtE,
since a more complete use of the carbon content is performed with respect to the combination
of combustion with anaerobic digestion. Again the scenario based on gasification reports
lower performances, while the one based on pyrolysis has the best energy and environmental
results.
C
ONCLUSION
From a technological point of view, the market of energy recovery from waste offers
today a wide number of proven technical systems only in reference to processes based on
waste direct combustion, i.e. WtE. WtE is the most widespread thermal treatment for waste at
the international level. It is a mature technology which has reached a high reliability.
Gasification and pyrolysis processes are far less common and especially applied to
particular typologies of wastes, with relatively small plant sizes. They present a significant
complication both at plant level and at operating level. Up to now, their reliability, in
reference to the continuous operation, is lower with respect to WtE.
From the results reported in this chapter, the gasification process coupled with syngas
energy recovery in a steam cycle does not offer a potential in the direction of the efficiency
improvement in energy recovery from waste, with respect to the traditional WtE.
