You have to realize that while "a bushel of corn needs approximately 4,000 gallons of water in a growing season. ... much of the water taken into a corn plant is released back into the air through transpiration. In fact,
one acre of corn gives off about 4,000 gallons of water PER DAY through evapo-transpiration, according to the USGS.1 Aden. “Water Usage for Current and Future Ethanol Production.
(removed link as it didn't work.)
{ I found some data on corn harvested and water usage. I got a production weighted average of 43 gal per gallon of ethanol produced for water usage to cultivate the corn. to that you can add the 3 gallons of water per gallon of ethanol produced used at the ethanol distillery (see link to survey below). here is the link to spreadsheet: http://sites.google.com/site/truthisstrangerthanfictionx/Ethanol_water_mile.xls } When an Ethanol distillery (they like to call them "Biorefineries") makes ethanol they also produce a feed supplement for cattle. The Protein portion of the corn is recovered and is used as a high nutrient cattle feed supplement. A portion of the water used in making ethanol is also used to produce this feed supplement. In 2008 the Ethanol industry produced in addiion to over 9 billion gallons of ethanol, over 26 million tons of cattle feed (23 million metric tons of distillers grains, 3 million metric tons of corn gluten feed, and 600,000 metric tons of corn glutenmeal). This was "roughly equivalent to the combined annual amount of total feed consumed by cattle on feed in Texas, Kansas, Nebraska, and Colorado — the nation’s four largest fed cattle states."_Renewable Fuels Assoiation.
Here is a link to the results of a survey of ethanol plant operators. They report using 3 gallons of water per gallon of ethanol produced which is actually better than the design specs of most of the newer ethanol plants today. The plant operators expect to bring water consumption down more with with process modifications and further design improvements. http://www.transportation.anl.gov/pdfs/AF/557.pdfAn analysis of the latest survey conducted by the RFA revealed that freshwater consumption in existing dry mill plants has declined to 3.0 gallon per gallon of ethanol produced, in a production-weighted average (Wu 2008), a significant drop of 48 percent in less than 10 years (Figure 18). This value is 17% lower than a typical dry mill design value ─ 3.6 gal/gal (Keeney 2007). In fact, some existing dry mills use even less by process modifications and production of WDG co-products in dry mill plants (as compared with DDGS) (Wang et al. 2007). Water use can be minimized further through process optimization, capturing of the water vapor from the dryer, boiler condensate recycling to reduce boiler makeup rate, etc. The ethanol industry maintains that net zero water consumption is achievable by water reuse and recycling using existing commercial technology and with additional capital investment.
http://74.125.93.132/search?q=cache:RB3C1_aqFVQJ:www.ethanolrfa.org/objects/pdf/outlook/RFA_Outlook_2009.pdf+ethanolrfa+water+to+make+ethanol&cd=2&hl=en&ct=clnk&gl=usPage 24
”More efficient use of water is a trend that will continue within the ethanol industry. New technologies promise to more efficiently use and recycle the water required for cooling towers, boilers and other pro-cessing components. Engineering and design firms estimate the average water use per gallon of ethanol produced is likely to continue to drop substantially in the next several years. One such firm estimates water requirements will soon be reduced “…to less than 1.5 gallons per gallon of ethanol produced. ”Some ethanol producers are now using waste water, or gray water to produce ethanol. "
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"corn requires large amounts of water to grow; a bushel of corn needs approximately 4,000 gallons of water in a growing season.
... much of the water taken into a corn plant is released back into the air through transpiration. In fact, one acre of corn gives off about 4,000 gallons of water per day through evapo-transpiration, according to the USGS.1 Aden. “Water Usage for Current and Future Ethanol Production.
..."what often goes unreported is that nearly nine out of every 10 corn acres in the United States are rain-fed and require no irrigation other than natural rainfall. Further, because most ethanol production occurs in the central Corn Belt where corn is primarily rain-fed, NREL says “As much as 96% of the field corn used for ethanol production is not irrigated at all.”
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CoProducts: Feed co-products represent an increasingly important share of profit opportunities for ethanol producers.
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FEEDING THE WORLD,FUELING A NATIONIn 2008, U.s. ethanol producers utilized approximately 3.2 billion bushels of corn to produce nearly 27 million tons of high quality livestock feed (23 million metric tons of distillers grains, 3 million metric tons of corn gluten feed, and 600,000 metric tons of corn glutenmeal) and 9 billion gallons of clean burning, renewable ethanol. To put these production volumes in context, consider that
the amount of feed produced by the ethanol industry in 2008 is roughly equivalent to the combined annual amount of total feed consumed by cattle on feed in Texas, Kansas, Nebraska, and Colorado — the nation’s four largest fed cattle states. Source: Renewable Fuels Association
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