Monday, May 4, 2009
5-47
The potential of ethanol production from the organic fraction of Municipal Solid Wastes
Mercedes Ballesteros, Ignacio Ballesteros, M.Jose Negro, J.Miguel Oliva, Felicia Saez, and Paloma Manzanares. Renewable Energies Department, CIEMAT, Avda. Complutense, 22, Madrid, Spain
The organic fraction of municipal solid wastes (MSW), which represents about 44% of garbage, is an easily recovered fraction that is an especially appealing feedstock for ethanol, because cellulosic materials comprise about 60% of the dry weight of a typical MSW stream. In 2007, Spanish households generated 24.000 tons of MSW of which a significant fraction was landfilled. The fact that the organic fraction of MSW has a relatively high carbohydrate content and the need to find a solution to its disposal problem has encouraged the research about its utilization for the production of fuel-ethanol. Further, unlike other cellulosic feedstocks, MSW has an already well-established collection system, and is available at a negative cost.
A number of process to convert MSW into biofuels are being developed using different production pathways such us combined thermo-biochemical process and concentrated acid hydrolysis technology. However, due to the heterogeneous nature of household cellulosic waste the enzymatic conversion route has not been well investigated.
In this work, results of laboratory experiments aimed to evaluate the performance of municipal organic solid wastes as substrate for ethanol production are shown. The process comprises a hydrothermal pre-treatment and the bioconversion of the pretreated substrate to ethanol by simultaneous saccharification and fermentation. The analysis of ethanol yields attained in the different laboratory conditions (substrate and enzyme loading, process time, etc) will be presented.