Systems and methods have been developed for reclaiming water contaminated
with the expected range of contaminants typically associated with
produced water in order to produce a treated water having a quality
adequate for reuse as a fracturing water. The system includes
anaerobically digesting the contaminated water, followed by aerating the
water to enhance biological digestion. After aeration, the water is
separated using a flotation operation that effectively removes the spent
friction reducing agents and allows the treated water to be reclaimed and
reused as fracturing water, even though it retains levels of
contaminants, including boron and methanol, that would prevent its
discharge to the environment under existing standards. The treated water
has had a sufficient amount of the gellation-inhibiting contaminants,
such as acrylamide friction reducing compounds, removed to allow the
treated water to be an economically viable fracturing water.