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The Water Footprint of Biofuels: A Drink or Drive Issue?Author: Rosa Dominguez-Faus, Susan E. Powers, Joel G. Burken, Pedro J. Alvarez Link to source material: http://pubs.acs.org/doi/abs/10.1021/es802162x Description: Ensuring inexpensive and clean water is an overriding global challenge noted as one of the Millennium Development Goals of the United Nations. This challenge will likely be intensified by the increasing demand for biomass-derived fuels (i.e., biofuels) for transportation biofuel needs, because (1) large quantities of water are needed to grow the fuel crops, and (2) water pollution is exacerbated by agricultural drainage containing fertilizers, pesticides, and sediment. These potential drawbacks are balanced by biofuels’ significant potential to ease dependence on foreign oil and improve trade balance(s) while mitigating air pollution and reducing fossil carbon emissions to the atmosphere. The water requirements of biofuel production depend on the type of feedstock used and on geographic and climatic variables. Such factorsmustbe considered to determine water requirements and identify critical scenarios and mitigation strategies. Feedstock cultivation, usually row-crop agriculture, is the most water-intensive of biofuel production stages. For example, evapotranspiration water requirements in the U.S. necessitate 500-4000 L of water to grow enough feedstock to produce1Lof ethanol (Lw/Le) (Figure 1); processing water requirements for a typical sugar cane or corn ethanol refinery are only 2-10 Lw/Le (17). Nevertheless, the water used in biofuel processing and other stages in biofuel production is often withdrawn from local point sources and can have localized impacts on water quality and quantity. Login to post comments Printer friendly version |
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