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The cultivation of cassava (Manihot esculenta) is widely spread in a variety of tropical countries with an estimated annual production of 291.9 million tons. The crop is the most important source of carbohydrates in producing countries. In Malaysia, cassava is mainly cultivated for starch production. Despite the economic and nutritional importance of cassava, there is only limited knowledge available regarding the overall environmental impacts of cassava starch production or the production of alternative food products like cassava crisps. This study presents an environmental assessment of different scenarios of cassava production and processing by a life cycle assessment (LCA) approach. The results indicate that the environmental impacts of cassava-based products can be reduced considerably with the utilization of processing residues for anaerobic digestion if the resulting biogas is used for the production of electricity and heat. In the industrial scenario, the results indicate that the highest relative reductions are achieved for cumulated energy demand (CED), global warming potential (GWP) and deforestation (DEF) with −39%, −26% and −18%, respectively, while in the advanced scenario, environmental impacts for CED, GWP, ozone formation potential (OFP) and water stress index (WSI) can be reduced by more than 10% with −281%, −37%, −16% and −14%, respectively. The impacts for global warming potential found in this study are slightly higher compared to other studies that focused on the carbon footprint of starch production from cassava, while the savings due to biogas production are similar. [ABSTRACT FROM AUTHOR]

The utilization of agricultural biomass for anaerobic digestion is increasing in Germany since the first version of the Renewable Energies Sources Act ( EEG) in 2000. Main products of this conversion process are biogas and digestate, whereby the biogas is mainly used for generation of heat and electricity in combined heat and power plants ( CHP). This study investigated the potential environmental impact of anaerobic digestion processes with different agricultural substrates by the life cycle assessment ( LCA) method. It focuses on liquid manure and energy crops as feedstock on the one hand and a comparison of four virtual model plants on the other hand. Besides global warming potential ( GWP), the impact categories eutrophication potential ( EP) and acidification potential ( AP) are presented in this work. The results show that greenhouse gas emissions can be reduced with anaerobic digestion of liquid manure as well as energy crops, particularly when digestate storage tanks are gas-tight. When energy crops are fermented together with liquid manure, the biggest credit for the avoidance of greenhouse gas emissions was given for the generation of electricity. The results differ from those of GWP when looking at the AP and the EP. These impact categories show similar results with a reduction of emissions for liquid manure in mono-digestion but increasing emissions for digestion of energy crops together with 0-35% liquid manure. [ABSTRACT FROM AUTHOR]