Penilaian Daur Hidup (Life Cycle Assessment) Bioetanol Berbahan Baku Limbah Tanaman Jagung
Abstract
Life Cycle Assessment (LCA) is the analysis system used in evaluating the environmental impacts of a product life cycle as a whole. LCA focuses on the factor to collect information and analyze the environmental impact caused by a product. This approach aims to avoid the mistakes of the outstanding environmental issues (UNEP, 1996; ISO, 1997. Ethanol or ethyl alcohol (familiar as “alcohol”, C2H5OH) is liquid has no colour with characteristic flamable, water soluble, biodegradable, and doesn’t give environmental impact if there’s contamination. Bioethanol is ethanol (alcohol), fermented from sugar, starches, and selullosic bimass (Demirbas, 2005). The purpose of this study were to identify the impact from life cycle of bioethanol made from corn stover with biological and chemical delignification stage and combination starter Zymomonas mobilis with Pichia stipitis and Saccharomyces cerevisiae with Pichia stipitis on stage fermentation and then determine the best process steps based on use of energy, raw materials, and pollution caused. The scope of this study include the transportation of raw materials; the use of boilers; electricity use; preparation of materials include mushroom breeding, starter, and demolition materials; preparation materials include delignification, hydrothermal I and II; Simultaneous Saccharification and Co-Fermentation (SSF) include pre-hydrolysis and fermentation; purification; and Waste Water Treatment Plant (WWTP). The use of LCA method conducted on eight specified design based delignification stage and the combination of starter during fermentation. Delignification of the R1 and R2 using Ca (OH) 2, R3 and R4 using white rot fungus Pleurotus ostreatus, R5 and R6 using Phanerochaete chrysosporium, whereas R7 and R8 use Tratemetes vercolor. Fermentation at R1, R3, R5, and R7 using Zymomonas mobilis and Pichia stipitis, while R2, R4, R6, R8 using Saccharomyces cerevisiae and Pichia stipitis. LCA method were performed, consist of inventory analysis and impact analysis. Inventory analysis, conducted by collected data related to the processes in the laboratory and the collection of literature related to energy demand and emissions generated. Impact analysis, done by created a matrix and flow chart the impact of significant impacts, where the assessment is based on inventory analysis has been done. The next stage is the selection of the best designs using Bayes method. Supplies of raw materials for the eighth design in produce 500 litre bioethanol 95% is 2,904.68 to 5,150.62 kg, energy demand 61,255.16 to 84,958.29 MJ, produce as much emissions 4,591.14 to 6,390.25 kg, solid waste 24,492.51 to 45,141.25 kg, and liquid waste 135,535.80 to 287,247.05 kg. Best design based on calculations used Bayes method is R7, the design with biological delignification used Trametes vercolor and fermentation used a combination starter Zymomonas mobilis dan Pichia stipitis. It is influenced by the ability to produce bioethanol by each design.