3.4. Results from impact assessment
The life-cycle environmental impact assessment covering cultivation
and harvesting, cassava chip production, transportation and
conversion of bioethanol production from cassava showed that the
ethanol conversion stage had the highest environmental impact in
almost all impact categories such as abiotic depletion, global
warming or greenhouse gas (GHG), photochemical oxidation, human
toxicity and eutrophication, except ozone layer depletion
and acidification categories as shown in Fig. 3. This can be attributed
to the use of coal for power and steam production during
the conversion process and wastewater generated in this process
as well as CH4 emission as discussed earlier. For cassava farming
and harvesting stage, significant effects observed were from the
production of chemical fertilizers extensively used in the cultivation