Wastewater Processing Cascade Distillation Subsystem Design and Evaluation

Water recovery from wastewater is essential for the success of long term missions. Honeywell Aerospace and the team comprising Thermodistillation Co. (Kiev, Ukraine) and NASA JSC Crew and Thermal Systems Division are developing an advanced wastewater processing subsystem that is based on centrifugal vacuum distillation that will be tested at the NASA JSC water lab. The wastewater processing cascade distillation subsystem (CDS) utilizes a multi-stage thermodynamic process to efficiently produce purified water, and its rotary centrifugal design provides gas/liquid phase separation and liquid transport (pumping) under microgravity conditions. The objective of the program is to demonstrate potable water recovery from various wastewater streams that is suitable to meet the requirements of present (ISS) and future (Lunar-Mars) human space missions.

This paper presents the subsystem design and the cascade distiller operational evaluation. Key performance and success criteria for the subsystem design are: water production rate at 5 kg/hr max, specific power consumption at less than ~140 watt/kg, and the successful operation of the technology in the NASA Lab. Experimental evaluation of the cascade distiller has demonstrated excellent thermodynamic performance at less than 100 watt/kg. The system will operate in a semiautomatic mode and the control algorithms have been formulated and tested experimentally. Successful experimentally. Successful completion of this project will significantly advance the technology readiness level of this subsystem.