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Three replicate aerobic-heterotrophic biotrickling filters were designed to promote the simultaneous biodegradation of graywater and a waste gas containing NH3, H2S and CO2. Upon visual observation of discolored solids, it was originally hypothesized that gas-phase CO2 concentrations were excessive, causing regions of anoxic zones to form within the biotrickling filters. Observed discolored (black) biofilm of this nature is typically assumed to be either lysed bacterial cells or anaerobic regions, implying alteration of operational conditions. Solid (biofilm) samples were collected in the presence and absence of gas-phase wastestream(s) to determine if the gas-phase contaminants were contributing to the solid-phase discoloration. Two sets of experiments (shaker flask and solids characterization) were conduced to determine the nature of the discolored solids. Results indicated that the discolored solids were neither anaerobic bacteria nor lysed cells.

The Bioregenerative Air Treatment for Health system has been proposed for Advanced Life Support (ALS) planetary base applications. The system will be operated as a biotrickling filter to simultaneously treat graywater and waste gas. Preliminary experiments have focused on carbon removal from a graywater simulant. Six bench scale biotrickling filter reactors were constructed and monitored continuously. After a reactor startup phase of 40 days, the average total organic carbon (TOC) removal for reactors packed with Tri-packs® packing material was 62%. A second set of experiments was designed to evaluate TOC removal using different packing materials (Bee-cell and Biobale). It was hypothesized that the alternative packing materials would reduce the effects of channeling in the reactors, thus improving TOC removal. However, TOC removal did not significantly improve during the second set of experiments.

Bioregenerative systems for removal of gaseous contaminants are desired for long-term space missions to reduce the equivalent system mass of the air cleaning system. This paper describes an innovative design of a new biofiltration test lab for investigating the capability of biofiltration process for removal of ersatz multi-component gaseous streams representative of spacecraft contaminants released during long-term space travel. The lab setup allows a total of 24 bioreactors to receive identical inlet waste streams at stable contaminant concentrations via use of permeations ovens, needle valves, precision orifices, etc. A unique set of hardware including a Fourier Transform Infrared (FTIR) spectrometer, and a data acquisition and control system using LabVIEW™ software allows automatic, continuous, and real-time gas monitoring and data collection for the 24 bioreactors. This lab setup allows powerful factorial experimental design.

Models for the components of a long-duration UAV power system are set forth. The models include the solar array, solar array power converter, fuel cell and electrolyzer system and corresponding power converter, and propulsion load. Based on these models, a power management control is derived, which when coupled with the component models, are used to simulate power system performance during start-up, through a day-night cycle, and through a solar eclipse.