NETL is using a state-of-the-art tool it developed to help a new research team evaluate the economic costs and benefits of capturing and purifying minerals that can be reused to create valuable products as part of desalination — the process of removing salt from brackish wastewater.

Brackish water is water that is saltier than fresh water, but not as salty as seawater. The effort is one of 12 projects recently funded by the U.S. Department of Energy (DOE) and the National Alliance for Water Innovation (NAWI) designed to improve desalination and water reuse technologies across the country.  

The project uses the Water treatment Technoeconomic Assessment Platform (WaterTAP), developed by NETL and colleagues at Lawrence Berkeley National Laboratory, the National Renewable Energy Laboratory, and Oak Ridge National Laboratory.

NETL’s Tim Bartholomew explained that WaterTAP is an open-source software tool funded by NAWI that supports researchers in predicting the performance and cost of innovative water treatment technologies. The short-term goal of these predictions is to guide research and development of the new technologies with the long-term goal of deploying the best performing technologies at the commercial scale.

According to NAWI, “the climate crisis, population growth, and changes in how communities use water contribute to a growing water scarcity problem worldwide. Many regions around the United States are now water-stressed, lacking the water supply required for daily needs, agriculture, and energy and materials production. To meet demand, it is critical that we develop technologies that provide alternative water sources and treat and use water in ways that are efficient, sustainable and cost-effective.”

The NETL-led project will investigate two key process challenges associated with desalinating brackish water. The first challenge is pre-treatment which is necessary to ensure that desalination equipment is not damaged. The second challenge is the disposal of the high-salt concentrate waste that is produced   in the desalination process. To address both challenges, the project attempts to reframe the problem by creating saleable products during pre-treatment and repurposing the waste brine as a product.

“The brine and its constituents could be sold to local industries that can use it,” NETL’s Alison Fritz added. “Developing technologies to capture and purify economically valuable elements from concentrate could significantly improve the cost-effectiveness of brackish water desalination.”

The project will examine the markets for potential products that could use the raw materials generated from the brine like building materials, fertilizer, road salts, caustic and sulfuric acid.

“We will estimate the cost and environmental impacts to extract the raw materials from brine during the desalination process,” Fritz said. “If we can identify technically feasible and sustainable reuse of bulk constituents from desalination, it could reduce costs for treatment systems in areas with limited access to safe drinking water, improve health outcomes, and create economic benefits for regions of the United States that currently don’t have reliable and safe potable water supplies like the Central Valley in California, regions of Texas, and Florida.”

Stanford University will head up another project with NETL and the city of Santa Barbara, California, that examines flexibility in operating desalination plants.

NAWI is a research program supported by the DOE Office of Energy Efficiency and Renewable Energy (EERE)’s Industrial Efficiency and Decarbonization Office and headquartered at Lawrence Berkeley National Laboratory. It seeks to secure an affordable, energy-efficient and resilient water supply for the U.S. economy through effective desalination processes that fosters a circular water economy in which every drop is accounted for, and all resources are reused.

NETL is a DOE national laboratory that drives innovation and delivers technological solutions for an environmentally sustainable and prosperous energy future. By using its world-class talent and research facilities, NETL is ensuring affordable, abundant and reliable energy that drives a robust economy and national security, while developing technologies to manage carbon across the full life cycle, enabling environmental sustainability for all Americans.