Chemical Technology July 2015

WATER TREATMENT

References A list of references for this article is available from the editor at chemtech@crown.co.za z

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).

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 http://dx.doi.org/10.1039/C4EM00376D

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.

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Chemical Technology • July 2015