Life cycle and economic assessments of engineered osmosis and osmotic dilution for desalination of Haynesville shale pit water

The treatment of oil and gas (O&G) exploration wastewaters by forward osmosis (FO) could make water management in the O&G industry more sustainable. Specifically, recovery of pit water from well drilling operations and hydraulic fracturing could reduce the impacts associated with wastewater transportation, deep well disposal, and fresh water procurement for subsequent hydraulic fracturing operations. This study evaluates the environmental and economic impacts of FO for treatment of O&G pit water through comparative life cycle impact and costing assessments; the FO technology is evaluated when operated as an engineered osmosis system and as a stand-alone osmotic dilution process. Cradle-to-grave life cycle inventories are developed for each FO process and evaluated using ten environmental impact categories. The relative environmental impacts of FO are found to be comparable to the transportation and pumping energy alone required for deep well injection. At the current state of the technology, the energy demand of the FO systems when operated with no upstream pretreatment is the single greatest contributor to the negative environmental impacts. At 75% water recovery, FO can potentially reduce pit water management costs by nearly 60% compared to deep well disposal, and pit water transportation requirements can be reduced as much as 63%. (C) 2015 Elsevier B.V. All rights reserved.