Zero-Liquid Discharge Desalination of Hypersaline Shale Gas Wastewater: Challenges and Future Directions

Abstract

Unconventional natural gas extraction from tight shale reservoirs, or shale gas, has recently emerged as an attractive energy resource to face the rising worldwide demand. Over the past decade, advanced technologies of horizontal drilling and hydraulic fracturing (“fracking”) have allowed the economic viability of shale gas exploration from rather unattainable deposits. Apart from optimistic growth projections, shale gas production is also responsible for worrying environmental and social implications, which are related, among others, to elevated freshwater consumption and hazardous wastewater generation. Within this framework, the ability of zero-liquid discharge desalination to promote water reuse and/or water recycling is critical for shale gas industry. Hence, application of effective desalination processes is mandatory to treat the large amounts of polluting hypersaline wastewater, alleviating environmental and public health impacts and enhancing overall shale gas process sustainability. This work outlines the challenges and future directions for ZLD desalination of shale gas wastewater.