Biological and physical polishing of a space based waste stream

A hollow fiber membrane bio-reactor (HFMBR) and hollow fiber microfiltration (MF) membrane cartridge treated a space habitation humidity condensate waste stream. The waste stream has an ideal ratio of organic carbon to nitrogen (C:N = 7:1) to promote biological treatment. Carbon and Nitrogen removal in the HFMBR was highest (76% and 43%, respectively) for the shortest retention time. Addition of an outside macronutrient source and pure oxygen, as opposed to lab air, showed a significant increase in carbon removal, but had no significant affect on nitrification/dentrification reaction rates (areal or volumetric). The MF module was used to polish the waste stream for potential reuse within the space habitation environment. The MF module provided 5-log removal of bacteria from the post-processor HFMBR effluent, as well as reducing turbidity and suspended solids to values less than 1 NTU/ppm. The MF module also showed small reductions in DOC and TN values (10-20%). The MF permeate then could theoretically be reintroduced into the space habitation system for reuse upon disinfection.