The first comprehensive study of American industrial water use was recently conducted by a team of scientists (led by Chris Hendrickson) at Carnegie Mellon University. Using computer models to analyze industrial water use, the scientists were able to estimate how much water is used by 400 different industrial sectors. The study was published in the American Chemical Society’s journal, Environmental Science and Technology.
Those of you who’ve been following our coverage of water footprints and virtual water are already aware of the imbedded water costs in various products and services. It comes as no surprise that the Carnegie study concluded that a majority of water use at the industrial level is the result of processing, packaging, and shipping—with irrigation making up a smaller part of the overall total.
According to the study, it takes 270 gallons of water to produce $1 worth of sugar, and 200 gallons to proceed $1 worth of pet food—and while those are some eye-popping numbers, I suspect I am not in alone in wishing that the study had tied the water amounts to specific units of measurement rather than cost, as prices can vary across communities and be influenced by a variety of other factors. Nevertheless, it’s certainly striking to see that a relatively inexpensive product—i.e. $1 worth of sugar—can carry with it such a large water footprint.
Some other interesting statistics from the study:
* Agriculture and power generation account for 9% of all direct water withdrawals in the US.
* 60% of water use is indirect (i.e. “virtual”).
* The food and beverage industry accounts for 30% of all indirect withdrawals in the US.
To view the abstract of the study (or purchase the full text), go to: http://pubs.acs.org/doi/full/10.1021/es903147k
To find out how much water is imbedded in your favorite food or beverage, check out our free iPhone app at www.waterprint.net.