Life Cycle Water Consumption and Wastewater Generation Impacts of a Marcellus Shale Gas Well

Abstract

This study estimates the life cycle water consumption and wastewater generation impacts of a Marcellus shale gas well from its construction to end of life. Direct water consumption at the well site was assessed by analysis of data from approximately 500 individual well completion reports collected in 2010 by the Pennsylvania Department of Conservation and Natural Resources. Indirect water consumption for supply chain production at each life cycle stage of the well was estimated using the economic input–output life cycle assessment (EIO-LCA) method. Life cycle direct and indirect water quality pollution impacts were assessed and compared using the tool for the reduction and assessment of chemical and other environmental impacts (TRACI). Wastewater treatment cost was proposed as an additional indicator for water quality pollution impacts from shale gas well wastewater. Four water management scenarios for Marcellus shale well wastewater were assessed: current conditions in Pennsylvania; complete discharge; direct reuse and desalination; and complete desalination. The results show that under the current conditions, an average Marcellus shale gas well consumes 20 000 m3 (with a range from 6700 to 33 000 m3) of freshwater per well over its life cycle excluding final gas utilization, with 65% direct water consumption at the well site and 35% indirect water consumption across the supply chain production. If all flowback and produced water is released into the environment without treatment, direct wastewater from a Marcellus shale gas well is estimated to have 300–3000 kg N-eq eutrophication potential, 900–23 000 kg 2,4D-eq freshwater ecotoxicity potential, 0–370 kg benzene-eq carcinogenic potential, and 2800–71 000 MT toluene-eq noncarcinogenic potential. The potential toxicity of the chemicals in the wastewater from the well site exceeds those associated with supply chain production, except for carcinogenic effects. If all the Marcellus shale well wastewater is treated to surface discharge standards by desalination, $59 000–270 000 per well would be required. The life cycle study results indicate that when gas end use is not considered hydraulic fracturing is the largest contributor to the life cycle water impacts of a Marcellus shale gas well.

A review of physical supply and EROI of fossil fuels in China

“…Hydraulic fracking is usually needed in extracting shale gas resources due to their low permeability, which will consume large amounts of pressurized water. Generally, one shale gas well will use more than 20 thousand cubic metres water, and large-scale development of shale gas will surely have serious impacts on local water resources (Jiang et al 2014;Hu et al 2013a, b). However, China itself is facing serious water shortage issues (Zhu et al 2001), which means that local water availability will be an important constraint for shale gas development.…”

Shale gas: a life-cycle perspective for UK production

“…Very few studies explore also other impacts: the water life cycle of shale gas extraction is analysed by Clark et al (2013b) and Jiang et al (2014) in the USA and Tagliaferri et al (2015) in the UK. The latter was a preliminary study by the same authors of this paper that however was very limited in scope as it did not consider different procedures for shale gas production nor the comparison with the gas grid mix.…”

Current perspectives on unconventional shale gas extraction in the Appalachian Basin

“…[70] Water management, from the water withdrawals to waste water treatment, is an important issue. [24,[70][71][72][73][74][75][76][77] The use of open impoundments in Pennsylvania for flowback and produced water recycling presents several environmental hazards. They may pose a threat to surface and near surface groundwater as the liners can leak.…”

“…In Pennsylvania 80% comes from untreated surface water with the remaining 20% from public water supplies. [24] In the eastern portion of Pennsylvania the Susquehanna River Basin Commission and the Delaware River Basin Commission manage water withdrawals. In Western Pennsylvania permits are provided by the PA DEP under the justification of water quality control.…”