U.S. shale gas production has increased 14-fold over the past
decade and reserves have tripled. Tapping this resource with
hydraulic fracturing (using pressurized liquids to fracture subsurface
rock) and other techniques pioneered by NETL and its research
partners has played an increasingly important role in greater
U.S. domestic oil and natural gas production over the past decade.
The water resources needed to hydraulically fracture the Marcellus
Shale and the potential effects of hydraulic fracturing on surface
and subsurface water sources have become key concerns for state
legislatures, land owners, and the public. This is especially
true as the number of issued permits continues to increase and
drilling expands to new areas of the Appalachian Basin.
Frac water contains significant amounts of constituents such
as salt, metals, sulfates, and chlorides. Additionally, this
water contains certain ingredients that are ‘proprietary’
in nature and not disclosed on manufacturers’ safety data
sheets (MSDS). The U.S. Environmental Protection Agency (EPA)
has recommended that publically owned treatment works (POTWs)
no longer accept natural gas frac water. New regulations specifying
frac water treatment guidelines are creating distinct challenges
for the shale-gas industry. These challenges exist because no
single-stage treatment technology capable of economically treating
frac water to discharge water quality standards has been fielded.
