Description: U.S. space exploration missions have long considered returning to the Moon and exploration of Mars that challenge life support systems. For these long duration missions, NASA is interested in replacing the iodine water treatment system with ionic silver. Although iodine treated water has been used successfully with the International Space Station, its use requires that the iodine be removed before being consumed by astronauts due to its adverse effects on the thyroid. For long duration exploration missions, minimal mass systems are desired that lessen logistical supply requirements for storing and distributing potable water. In particular, it is imperative that an effective biocide is used that prevents microbial growth, biofilm formation, and microbially induced corrosion in the water storage and distribution systems. To address these needs, Reactive Innovations, LLC successfully demonstrated a Phase I program that developed an electrochemical silver ion generator to produce an effective biocide solution for disinfecting water throughout the water storage and distribution system. A follow-on Phase II program will further develop and optimize this cell and control system. This biocide delivery system will be demonstrated in a relevant environment showing its long life performance for preventing biofilm growth.

Benefits: A potable water treatment process is needed to prevent microbial growth and biofilm formation in the water storage and distribution system for long duration missions. Silver ions have been proven by NASA to be effective for such microbial control, however, there remain significant challenges with the biocide delivery system and materials of construction that are compatible with silver. Our proposed process produces an effective delivery system with a control system that prevents silver deposition on the wetted materials of construction. This offers expanded degrees of freedom for designing the water system.

Silver ion water treatment systems have been used in commercial systems for treating potable water. The proposed technology produces a better distribution of silver ions in the water system that minimizes gradients that affect primary current distributions that deposit silver elsewhere in the water flow system. Low energy and inexpensive materials help drive the technology toward commercial viability.