In this study, we will report on the development and ground testing results of the novel ultrasonic human solid waste dryer at scale and its water extraction performance. Unlike conventional thermal drying methods, direct contact ultrasonic drying technology does not require substantial heat for water evaporation. Therefore, it is not constrained by the high energy input needed for water vaporization. This innovative drying method removes water by rapidly shaking the object (on a micron-scale) utilizing piezoelectric transducers. By partially bypassing the evaporation process, the technology demonstrates significantly higher efficiency and drying speed for bagged human solid waste. Previously, the performance of this platform technology for human fecal drying has been shown in the laboratory and at the benchtop scale. The team also demonstrated a lab-scale system performance under zero Gravity conditions and parabolic flights. In this paper, we will report on the full-size machine design and development process and the ground testing results of the ultrasonic drying performance of simulated feces and its water capture potential. This study will also report our team's effort to make the process as automated as possible for flight crew members' ease of use. The results of this study serve as the cornerstone for developing the first human solid waste dryer system for ISS, Moon, Mars, and other space applications.
Bigelow et al. (Sun,) studied this question.