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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.

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.

Complete reuse of graywater will be essential during long duration human space missions. The highest loaded and most important component to remove from graywater is surfactant, the active ingredient in soaps and detergents. When considering a biological treatment system for processing of graywater, surfactant biodegradability becomes a very important consideration. Surfactants should be chosen that are degraded at a fast rate and yield inconsequential degradation byproducts. Experiments conducted for this research examined the biodegradation of the surfactants in Pert Plus for Kids, disodium cocoamphodiacetate (DSCADA) and sodium laureth-3 sulfate (SLES), using respirometry. Rates of CO2 production, or ultimate degradation, are reported. DSCADA was found to be toxic to bacteria when present at 270 ppm whereas no toxicity was observed during experiments with SLES.

An important function of life support systems developed for a long duration human mission to Mars is the ability to recycle water and air. The Bio-Regenerative Environmental Air Treatment for Health (BREATHe) is part of a multicomponent life support system and will simultaneously treat wastewater and air. The BREATHe system will consist of packed bed biofilm reactors. Model waste streams will be used for experiments conducted during the design phase of the BREATHe system. This paper summarizes expected characteristics of water and air waste steams that would be generated by a crew of six during a human mission to Mars. In addition to waste air and water generation rates, the chemical composition of each waste stream is defined. Specifically, chemical constituents expected to be present in hygiene wastewater, dishwater, laundry water, atmospheric condensate, and cabin air are presented.