I was on a radio talk show with Bill Bunkley in Florida on September 26 when a caller who sounded otherwise sympathetic to fracking said the water used in fracking becomes “permanently toxic” and cannot be used for anything else, whereas water used for ethanol is generally just for irrigating corn fields and most of it recharges the aquifer.
I admitted to not knowing the fate of the water used for fracking but said I understood the water is re-injected below the level of aquifers and therefore didn’t pose a public health concern. He then expressed concern that this water was therefore “lost forever,” and we were permanently reducing the world’s supply (or at least a region’s supply) of freshwater. I invited the caller to send a message to firstname.lastname@example.org with his question and said we would post the answer at our Web site. I guess the email hasn’t arrived. So I asked Isaac Orr, a writer who studied geology with expertise on the subject of hydraulic fracturing, to reply to my understanding of the question, as stated above. Here is Isaac’s reply:
The caller said that the water is permanently contaminated, which isn’t true. The water can be treated, but it takes more than just your run of the mill water treatment facility to handle the job. The average fracked well uses approximately 2-4 million gallons of water. Of this amount, 80-90% of the original water used stays in the well permanently, i.e. is removed from the water cycle.
The other 10-20% of that water flows back to the surface (flowback water). In the Marcellus Shale, 90% of the flowback water is treated and recycled (which brings it back into the water cycle), while 10% of this water is trucked to disposal wells (removed from the water cycle).
So, while the water used for fracking isn’t made “permanently toxic,” most of it is not in fact returned to the water cycle. The bright side is hauling all of this water is expensive, and companies are constantly looking for ways to use less water to achieve the same level of fracturing. Also, from a global perspective, the amount of water being used for fracking is very small.