Low-Energy Water Recovery from Subsurface Brines


Subsurface plot showing the increasing TDS<br/>concentration in water with depth at a possible<br/>CO<sub>2</sub> storage site.
Subsurface plot showing the increasing TDS
concentration in water with depth at a possible
CO2 storage site.
Research Triangle Institute (RTI)
Website:  Research Triangle Institute
Award Number:  FE0026212
Project Duration:  09/01/2015 – 12/31/2017
Total Award Value:  $937,500
DOE Share:  $750,000
Performer Share:  $187,500
Technology Area:  Plant Optimization Technologies
Key Technology:  Water Management R&D
Location:  Research Triangle Park, NC

Project Description

The objective of this project is to develop and demonstrate bench-scale feasibility of a low-cost, low-energy water treatment process using non-aqueous solvents (NAS) for the economical extraction of clean water from high total dissolved solids (TDS) brines. TDS is a measure of the amount of dissolved matter in water and a reflection of the salinity—the energy required for separation increases with salinity. The high TDS levels in concentrated brines generated from CO2 subsurface storage and fossil fuel extraction (often eight times higher than those of seawater) make the current state-of-the art approaches to water treatment and disposal, such as reverse osmosis (RO), untenable. Specific project objectives are to identify candidate solvents that can absorb water under one condition and release it under better conditions; test different solvents and/or mixtures of solvents for optimum water uptake and release to maximize water recovery from 180,000 parts per million TDS brine; develop optimum conditions to maximize the kinetics of the process; test water quality and, if necessary, develop a downstream process to satisfy potable water standards; and develop strategies to optimize the overall process and perform a techno-economic assessment for scale-up.

Project Benefits

This water extraction technology approach addresses the two major challenges associated with treating this type of water: (1) the NAS can be used to treat water with very high TDS content and (2) the novel solvent method can be applied at large scale and low cost and energy. The successful development of this approach will provide a comprehensive solution to the water management issues encountered in high-TDS brine treatment, advancing expanded water reuse and discharge options beyond those that are currently feasible. This solvent technology will conserve precious water resources and reduce the environmental impact of concentrated brines. Other anticipated benefits of the proposed technology include low energy costs, low capital expenditure costs, a high-quality effluent, and easy scale-up.

Contact Information

Federal Project Manager 
Omer R. Bakshi: omer.bakshi@netl.doe.gov
Technology Manager 
Briggs White: briggs.white@netl.doe.gov
Principal Investigator 
Dr. Young Chul Choi: ycchoi@rti.org

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