Current environmental control and life support system (ECLSS) technologies aboard the International Space Station (ISS) recycle and process low strength wastewater within chemical and anaerobic bioreactors using precise control of temperature and pH, amidst strict processing timelines. However, these processes become ineffectual at low temperatures unless significant energy is expended to add heat. These processes are also unable to process high strength wastewater. As part of the long-term exploration and utilization of space, extending humans' presence in orbit as well as onto the Moon, Mars, and beyond, there is a need for processing high strength wastewater in a variety of harsh environmental conditions. Terrestrial uses for processing such wastewater have also been identified in frigid and/or polar locations. An Electrocatalytic System (ES) has been developed that comprises custom electrode pairs and catalysts optimized to selectively target molecules of specific contaminants. Target molecules are disaggregated into constituent atoms, typically benign gases that can be safely vented or captured for re-use. Benefits include low physical weight and size, insensitivity to contaminant load (effective on both high and low concentrations), insensitivity to wastewater age and to environmental conditions (e.g., not affected by wastewater temperatures and time-changing composition), "instant on/off" operation allowing discontinuous operation only when needed or according to power availability, requiring no consumables, and providing extreme reliability and stability with no moving parts and long-lived materials. This paper provides experimental results from a joint Space Florida Israeli Innovation Authority Partnership research project conducted in Israel and the US using an ES optimized for nitrogen compounds typical to manned spaceflight wastewater (urea and ammonia). The results show that ES is a superior next-generation technology providing an ability to process and achieve complete decomposition of high to low strength wastewater pollutants over broad and dynamic conditions while requiring only modest electrical power.
Grimes et al. (Sun,) studied this question.