Geology Reference
In-Depth Information
At the end of fracking, a well is commonly flushed with water, sometimes blen-
ded with a friction reducer, under pressure. Some of this wastewater is recovered
after fracking and must be carefully disposed of (more on this below).
Water remains by far the largest component of fracking fluid. The initial drilling
to the EPA, the total volume of water used to hydrofrack a well ranges between
65,000 gallons, such as for shallow coal bed methane production, to 13 million gal-
gallons of fluid, with large projects using up to 5 million gallons (equivalent to the
amount of water used by approximately 50,000 people during the course of one
day).
Once the hydrofracking fluid has been injected and pressure from the pumps is
released, fracturing fluid known as “flowback” surges back up through the bore-
hole to the surface. “Produced water” is fluid that returns to the surface once the
well has started producing natural gas or oil. Collectively, flowback and produced
water are known as hydrofracking “wastewater,” which is suffused with salts,
chemicals, debris scoured from the wellbore, and even naturally occurring radio-
active elements.
Because it is contaminated, the question of how to capture, store, and treat mil-
lions of gallons of wastewater is a knotty one, and the industry has resorted to
several different strategies. In western and southern states, wastewater is often in-
jected back underground into storage wells; when injected into geologically act-
wastewater to be spread on roads or fields, for dust suppression or de-icing. Envir-
onmentalists worry that the toxins will wash into freshwater and food supplies. In
certain cases, wastewater is recycled for use in other wells. In eastern states like
Pennsylvania, much of the wastewater is shipped by pipeline or truck to public
sewage treatment plants; but those plants are generally not equipped to process the
chemicals or the naturally occurring radioactive material that is sometimes dredged
up. The improvement of wastewater recycling and disposal methods is a major fo-
cus of the industry. (I discuss the concerns about wastewater and earthquakes at
