In an effort to promote water reuse and decrease the energetic demands of traditional water treatment mechanisms, CAER is working to develop next generation separation technologies that can handle a growing list of process needs. For lower concentration salt streams, CAER has developed advanced capacitive deionization (CDI) processes that can use low voltage methods (<1.2 V) to reversibly remove ionic contaminants from multiple feed water sources. These CDI separation cells incorporate surface charge-enhanced carbon materials to increase the separation performance and lifetime.

In addition to this technique, CAER is developing electrochemical methods for the removal of heavy metal compounds found in wastewater streams. Through targeted voltages and residence times, specific compounds can be easily and safely removed from these streams. CAER also works on more conventional membrane technologies including nanofiltration membranes for partial salt separations as well as zeolite dewatering membranes that can be used to treat water streams with >100,000 ppm dissolved solids. Membrane separations used by CAER rely on elevated pressures and temperatures to achieve substantive treatment.

Capacitive deionization (CDI) is an emerging technology for water desalination, and is based on the phenomenon of ion electrosorption. Especially for low salt concentration streams, like brackish water, CDI is a promising alternative to established technologies such as reverse osmosis.

CAER is currently working on modular, intensified water treatment and separation technology for flue gas desulfurization (FGD) wastewater, enhanced water recovery (EWR) from saline aquifers at CO2 injection sites, and zeolite dewatering of various complex wastewater and process streams. Projects related to these applications include:

• DE-FE0031555, “Intensified Flue Gas Desulfurization Water Treatment for Reuse, Solidification, and Discharge”;
• DE-PI0000017, “Demonstration of the Use of CO2 for Enhanced Water Recovery”