Chemical Technology July 2015

29 / 40

27
Chemical Technology • July 2015
ment is applied before it can be used (re-used) for hydraulic
fracturing. In many cases this involves chlorine dioxide or
hypochlorite treatments.
Such treatments will enhance the active species pres-
ent to convert the naturally occurring hydrocarbons to
chlorocarbons and organobromides. Further studies will
be required to determine if the reactions are occurring
downhole or during treatment of produced water. In either
case this would suggest that chemical treatments should
be limited since they cause the formation of unwanted
non-naturally occurring compounds; treatments involving
separation are preferred on long-term safety grounds. We
believe that analysis of the detailed composition of the
produced waters also highlights the problems in future
treatment protocols, in particular the development of a
process that allows for the removal of a wide range of
organic compounds[16,32-34].
Final analysis
Hydraulic fracturing has become a controversial tech-
nology in the development of unconventional shale gas
reserves. The large volumes of water traditionally used
during the hydraulic fracturing process and the resulting
produced and flowback waters are of current environ-
mental concern and disposal problem for producers.
Knowledge of the types of organic impurities is important
in determining the method of treatment and potential
water re-use. Findings of recent studies are reported on
and recommendations and limitations of specific water
treatment methods are offered.
Acknowledgements
This work was supported by the Robert A Welch Founda-
tion (C-0002) and the Welsh Government Sêr Cymru Pro-
gramme. The authors acknowledge the encouragement
and advice of Jake Davis and Waymon Votaw (Lance Energy
Services).
References
A list of references for this article is available from the editor
at z
This article originally appeared in the publication of the Royal
Society of Chemistry entitled ‘Environmental Science: Process-
es and Impacts’ and is (with kind permission) republished here
in a shortened form. For more information and to view the full
original article go to
WATER TREATMENT
Hydraulic fracturing has
become a controversial tech-
nology in the development
of unconventional shale gas
reserves. The large volumes
of water traditionally used
during the hydraulic fractur-
ing process and the resulting
produced and flowback waters
are of current environmental
concern and disposal problem
for producers.