Wastewater from hydraulic fracturing in the UK: assessing the viability and cost of management

Abstract

The safe and effective management of wastewaters from unconventional hydrocarbon production using the hydraulic fracturing (fracking) process poses a major challenge. Exploitation of unconventional hydrocarbons, such as shale gas, remains controversial in the UK primarily due to concerns surrounding the hydraulic fracturing process required to extract the resource. The key issue of how waste fluids produced by hydraulic fracturing in the UK will be safely managed has yet to be adequately addressed, and the capacity for the specialist treatment required is currently uncertain. To address this critical knowledge gap we review, for the first time, the available management options for these waste fluids in the UK. We find that these are limited in comparison to the options available in the U.S., due to uncertainty surrounding whether wastewater injection wells will be permitted in the UK. Consequently, it is highly probable that these fluids will need to be treated and safely disposed of at the surface. In order to constrain the composition of wastewater which will require treatment in the UK, we analyse the only existing data set of returned waters from hydraulic fracturing (n = 31). We supplement this with measurements of wastewater from UK conventional onshore hydrocarbon (n = 3), and offshore hydrocarbon (n = 14), operations which produce water from similar formations as those currently targeted for shale gas exploration. Comparison of this limited UK data to the more extensive unconventional production dataset from the United States (n = 3092) provides confidence in our projected UK wastewater compositions. We find that the high level of salinity and concentration of naturally occurring radioactive material (NORM) in UK wastewaters will be problematic to treat for disposal into a freshwater environment. We use our data compilation to estimate costs of treating such wastewaters in a number of relevant scenarios. We find that the projected salinity in FP waters from UK hydraulic fracturing operations can be treated at a cost of between $2701 (∼£2000) and $1 376 093 (∼£1 047 000) per well, requiring between 2 and 26% of expected revenue. Additional costs, specific to the UK of up to £163 450 per well, will be incurred due to the legislative requirement for disposal of NORM concentrated sludge in permitted landfill sites. We find that existing capacity to receive NORM waste at currently permitted UK treatment facilities is limited, and that this will pose management problems if wastewaters are generated from multiple unconventional wells simultaneously.

Addressing the risks of induced seismicity in subsurface energy operations

“…In Europe, the regulatory framework that governs unconventional energy development is developing. In the United Kingdom, uncertainty remains in unconventional oil and gas development as to quantities of produced wastewater and regulations and mechanisms for treatment and reuse or disposal (O'Donnell, Gilfillan, Eldmann, & McDermott, 2018). Where reinjection of wastewater for disposal may be allowed in certain circumstances it would require careful regulation for the avoidance of induced seismicity.…”

Public Health and Unconventional Oil and Gas Extraction Including Fracking: Global Lessons from a Scottish Government Review

“…Nearly all reviews include some analysis of fracking impacts on air and water [ 1 , 9 , 10 ]. In addition to universal recognition of the potential impacts in these areas fracking research is constantly throwing up new findings that affect risk assessments and it would be difficult for this reason to compare the evidence from some reports from 2012 with publications from 2017 [ 11 , 12 , 13 , 14 , 15 , 16 ]. Different countries and regions may also be faced with very different geological, economic, social, and other conditions that could impact on policy decisions.…”

Utilising Principles of Earth Jurisprudence to Prevent Environmental Harm: Applying a Case Study of Unconventional Hydraulic Fracturing for Shale Gas in the United Kingdom

“…Wastewaters cannot be released into freshwater systems (rivers, streams, canals, the sea) without being treated to reduce salinity (O'Donnell et al 2018).…”

“…There are three main problems associated with the treatment of wastewaters. First, it is an expensive process (Hammer et al 2012;O'Donnell et al 2018), which means operators may attempt to find the cheapest method of disposal in order to ensure monetary profit. Second, produced water may be allowed by the Environmental Regulator (the Environment Agency (EA) to be re-introduced into a well (as a storage solution), which reduces the need for treatment.…”

“…In the United States, the re-injection of wastewaters has been correlated directly with earthquakes (Ellsworth 2013;Estrada and Bhamidimarri 2016) and may also affect the integrity of wells (Folger and Tiemann 2016). Finally, the capacity for specialist wastewater treatment facilities in the UK to deal with fracking waste has been questioned (O'Donnell et al 2018), due largely to the anticipated toxicity and salinity of fracking wastewaters. O'Donnell and colleagues (2018) found that there may be only four sites in the UK that hold the required specialist license to deal with contaminated wastewaters.…”