Sbir phase II: continuous salt-free softening via a scalable redox-mediated electrochemical system

The National Science Foundation awarded Waterus LLC a $1.234 million cooperative agreement on August 1, 2026, under the NSF Technology, Innovation, and Partnerships program (CFDA 47.084) to develop a continuous, salt-free water softening system using a scalable redox-mediated electrochemical architecture.

The project advances a novel electrochemical approach that replaces conventional salt-based ion exchange with a continuous, electricity-driven process to selectively remove hardness ions without chemical regenerants. Phase II research and development scales the concept from laboratory validation to a household-capable system operating under realistic residential flow rates and pressures. Work includes iterative design, fabrication, and testing of multi-stack electrochemical cells to improve mechanical robustness and sealing reliability; advanced modeling and experimental validation to optimize flow distribution, electrical performance, and material durability; full-scale prototype integration and evaluation through laboratory testing and extended residential field trials; and design for manufacturability, long-term operational stability, and safe handling of mineral byproducts. The system uses minimal electricity, requires almost no maintenance, and eliminates the need for harsh chemical additives.

Performance occurs in Irmo, South Carolina, with a period of performance from August 1, 2026, through July 31, 2028. The $1.234 million represents the obligated amount under the cooperative agreement.

Abstract

The broader/ commercial impact of this small business innovation research (sbir) phase II is the advancement a new salt-free softening system that cleans without using harsh chemical additives. The system uses very little electricity and requires almost no maintenance, making IT a convenient and affordable choice for homeowners. This project investigates a novel electrochemical approach to softening, replacing conventional salt-based ION exchange with a continuous, electricity-driven process. The core innovation is a reversible, redox-mediated system that selectively removes hardness ions without chemical regenerants. This represents a fundamentally new paradigm requiring the tight integration of electrochemistry, advanced materials, and fluidic design. The core focus is on the development of continuous-flow deionization architecture. The system aims to achieve efficient hardness removal with minimal energy and waste. This approach departs from established batch-regeneration models, offering a pathway toward compact, low-maintenance solutions. Phase II r & d will advance this concept from laboratory validation to a scalable household system capable of operating under realistic residential flow rates and pressures. Research activities include the iterative design, fabrication, and testing of multi-stack electrochemical cells to improve mechanical robustness and sealing reliability. Advanced modeling and experimental validation will optimize flow distribution, electrical performance, and material durability. The system will be integrated into full-scale prototypes and evaluated through laboratory testing and extended residential field trials. Additional efforts focus on design for manufacturability, long-term operational stability, and the safe handling of mineral byproducts. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the foundation's intellectual merit and broader impacts review criteria.- subawards are planned for this award.