Advancing Water Treatment and Desalination Technologies

September 6, 2023

Innovative water treatment and desalination technologies hold promise for building climate resilience, realizing a circular water economy, and bolstering water security. However, more research and development is critical not only to radically lower the cost and energy of such technologies, but to effectively treat unconventional water sources. Conventional water supplies, such as fresh water and groundwater, are typically used once and thrown away, rendering this valuable and finite resource inaccessible for further use. Since its launch in 2019, the National Alliance for Water Innovation (NAWI) has made strides in developing new technologies to economically treat, use, and recycle unconventional waters (such as brackish groundwater, municipal and industrial wastewater, and agricultural run-off), which could point to a future where water equity and security is accessible to all.

Led by Lawrence Berkeley National Laboratory  (Berkeley Lab) and supported by the United States Department of Energy, NAWI is a five-year, $110 million research program and public-private partnership. NAWI brings together over 1670 individual NAWI Alliance members, over 400 partnering organizations, and numerous water research facilities.

“NAWI is driving breakthrough research to reduce the price, energy costs, and greenhouse gas emissions of new water technologies,” said Peter Fiske, executive director of NAWI. “Our work also bridges cutting-edge research with real people and places, such as producing secure, reliable, and affordable water for communities that are most in need.”

NAWI’s robust research portfolio spans analysis for water-energy grid integration to development of algorithms, models, and adaptive process controls for resilient operations. Now in its third year of operation, NAWI is supporting pilot projects that will treat unconventional water sources to provide usable water in real-world environments. Many of the pilot projects partner directly with communities and groups that have historically been underserved by existing water supplies. Each project will also generate a range of data sets usable by other researchers seeking to advance the field of data analysis and automation, and fault detection in water treatment systems.

These 5 NAWI pilot projects are transforming water treatment and desalination technologies.

Removing Arsenic from California Well Water for Rural Communities

Logan Smesrud (left), Jay Majmudar, the Rev. Dennis Hutson, and Eleanor Chin (right) with the arsenic treatment system on Hutson’s farm. (Credit: Ashok Gadgil)Arsenic, a naturally-occurring carcinogenic contaminant, is widely present in groundwater. In both California and around the world, many wells are contaminated with arsenic levels surpassing safety thresholds. This compels communities to either set up costly and intricate purification setups or cease using their local wells, resulting in the inconvenience of traveling long distances to procure water for domestic purposes. This initiative will demonstrate a new simple, dependable, and highly automated electrochemical arsenic-removal process employing iron and electrical currents. This method ensures the secure elimination of arsenic from well water while requiring minimal human intervention. Collaborating with the residents of Allensworth, California – a rural community whose residents travel significant distances to pay for retail water from a kiosk – is central to this project.

Turning Waste to a Valuable Resource for a Circular Economy

Desalination methods commonly recover a portion of pure water while generating a byproduct known as brine or concentrate, which contains high levels of salt and poses challenges for economical and environmentally friendly disposal, particularly at onshore desalination plants. This project centers on creating and implementing an innovative approach to intensify the concentration of brine through electrodialysis. This technique not only increases water yield but also converts the dissolved salts into valuable industrial chemicals. The initial testing of this system will take place at the Kay Bailey Hutcheson Desalination Plant situated in El Paso, Texas.

Enhancing Water Treatment Efficiency to Minimize Waste and Maximize Sustainability

The concept of desalination and repurposing of municipal, industrial, and agricultural wastewater presents an appealing strategy to enhance the dependability and resilience of water resources. However, the existence of dissolved minerals capable of obstructing reverse osmosis membranes and components, a phenomenon known as scaling, imposes constraints on the volume of water that membrane processes like reverse osmosis can restore. This project seeks to incorporate an innovative, exceptionally efficient technique for extracting scale-forming ions from concentrated brine solutions, thereby enabling significantly elevated water recovery rates and reducing waste brine volume. Through a mobile testbed, this advancement will help ensure high-recovery desalination across five locations in California.

Advancing Membrane Technology for Greater Resource Recovery

Electrodialysis Metathesis (EDM) is a desalination process that employs specialized membranes and chemical processes to generate fresh water. It also converts residual brine into two distinct streams: one rich in calcium and the other rich in sulfate. These streams hold the potential for further refinement into valuable industrial chemicals, thereby creating an additional revenue stream from the desalination process. This approach also aids in diminishing the volume of waste brine generated. Historically, EDM has necessitated the addition of sodium chloride (NaCl) to provide the essential ions for forming these distinct solutions. This NAWI-supported project implements a novel ion-selective membrane technology to eliminate the requirement for supplementary NaCl, potentially leading to a reduction of up to 50% in the energy demands of conventional EDM. The effectiveness of this system will undergo rigorous testing at the Brackish Groundwater National Desalination Research Facility, situated in Alamogordo, New Mexico, under the oversight of the U.S. Bureau of Reclamation.

Transforming Municipal Wastewater to Drinking Water to Improve Water Security

A team from the Colorado School of Mines has developed a Direct Potable Reuse trailer capable of converting wastewater into safe, affordable drinking water. (Credit: Peter Fiske)Municipal wastewater can be reprocessed into drinking quality water. Reverse osmosis has traditionally been a final treatment step that can provide the high purity required to satisfy drinking water quality regulations, but reverse osmosis generates a brine waste stream and drives up the cost and energy required for direct potable reuse. This project will perform a side-by-side demonstration at Silicon Valley Clean Water’s treatment plant in Redwood City, California, of both a reverse osmosis-based treatment train and a novel treatment train that achieves nearly the same purity without using reverse osmosis. The team will also investigate how different types of wastewater treatment technologies produce effluents that are either easier or harder to transform into drinking quality water.

NAWI is led by DOE’s Lawrence Berkeley National Laboratory in collaboration with National Energy Technology Laboratory, National Renewable Energy Laboratory, and Oak Ridge National Laboratory, and is funded by the Office of Energy Efficiency and Renewable Energy’s Industrial Efficiency and Decarbonization Office.

This article originally appeared at the Berkeley Lab News Center.