1 2008-01-2052 Development and Design of a Low Temperature Solid Waste Oxidation and Water Recovery System James A. Nabity, Erik W. Andersen, Jeffrey R. Engel TDA Research, Inc., 12345 W. 52 nd Ave, Wheat Ridge, CO 80033 David T. Wickham Reaction Systems LLC, Golden, CO 80401 John W. Fisher NASA Ames Research Center, Moffett Field, CA 94035 Copyright © 2008 Society of Automotive Engineers, Inc. ABSTRACT In February 2004 NASA released “The Vision for Space Exploration.” The goals outlined in this document include extending the human presence in the solar system, culminating in the exploration of Mars. A key requirement for this effort is to identify a safe and effective method to process waste. Methods currently under consideration include incineration, microbial oxidation, pyrolysis, drying, and compaction. Although each has advantages, no single method has yet been developed that is safe, recovers valuable resources including oxygen and water, and has low energy and space requirements. Thus, the objective of this work is to develop a low temperature oxidation process to convert waste cleanly and rapidly to carbon dioxide and water. Previously, TDA Research, Inc. demonstrated the potential of a low temperature dry oxidation process using ozone in a small laboratory reactor. Currently, TDA and NASA Ames Research Center are developing a pilot scale low temperature ozone oxidation system to convert organic waste to CO 2 and H 2 O. The system also disinfects the waste and remaining water, and recovers not only the water content of the waste but also generates additional water that can be utilized by the crew. Tests are being conducted with model wastes in a reactor design that maximizes the contact between the reactants by mixing the waste with water, which also makes the oxidation process extremely selective to CO 2 and H 2 O and mitigates the rapid combustion events that were seen in the dry oxidation reactor. An ozone recycle loop was recently added to the system, which significantly increased the waste oxidation rates. The reactor operating conditions were then optimized using the design of experiments technique to maximize the waste oxidation rate. Currently, a pilot scale, fully automated system is being designed that will be capable of handling many different types of waste. The waste oxidation rates achieved to date, along with current waste generation rate models, indicate that all of the waste from a single crew member in one day can be processed in a vessel ranging in size from 8.2 liters (2.2 gallons) for a short term mission to 9.9 liters (2.6 gallons) for a long term mission. In addition, if the system were used solely as a fecal matter oxidizer the reactor size would be only 0.7 liters. At the conclusion of the project the system will be delivered to NASA Ames for evaluation. INTRODUCTION A critical need for space missions is an effective method to control solid waste. The current estimates of solid waste generation rates are about 1.69 kg/CMD (kilograms per crew member day) for long duration space missions and 1.39 kg/CMD for short term missions 1 . If one assumes that a 180 day mission to Mars will include six crew, a total of 1825 kg of waste will be generated. Without processing and using the highest densities that have been achieved to date of 64 kg/m 3 , a space of approximately 28.5 m 3 would be required to contain this waste 2 . In addition to occupying valuable space, leaving waste unprocessed could cause the crew to be exposed to odors and biohazards, which would be a serious threat to their health and morale. Moreover, since leaving waste on the surface of Mars is undesirable, all waste generated on the way to the planet along with that produced during the surface stay is to be transported back. Thus, the additional launch