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In order to support effective recycling of resources in a bioregenerative life support system (BLSS), the processing of inedible agricultural wastes into edible food products must be included. The process of converting agricultural waste into usable food resources is called secondary food production. Secondary food production offers a way to reclaim part of the energy and nutrients already sunk in inedible biomass, thus increasing the efficiency of the BLSS and crop harvest index. However, multi-step processes and lower yields and acceptability have made some secondary food production processes in the past problematic and costly. This paper presents preliminary process descriptions for secondary food products which are likely to be cost effective and well accepted: sugar syrup prepared from biomass hydrolysate, single cell oil produced from biomass hydrolysate, and Pleurotus mushroom fruit bodies grown on recalcitrant biomass and unused substrate.

Brine dewatering by evaporation on porous media, and collection of wastewater evaporation condensates rich in organic carbon, both provide favorable environments for microbial growth, such as mold overgrowth of rayon wicks in the AES brine evaporation system, and bacterial biofilms on condensate-wetted surfaces. The mold growth reported on AES wicks by Campbell et al. (2003) has been identified by microscopic and molecular techniques as chiefly Chaetomium spp, most likely C. globosum, with minor occurrence of Penicillium, and other fungal species. Bacteria from the genus Bacillus was also isolated. A stable bacterial consortium dominated by three species was recovered from initially-sterile glass surfaces wetted with sterile Biological Water Processor Effluent Ersatz (Verostko et al., 2004) and exposed to humidified air over a period of one week. The species were identified as Enterobacter aerogenes, Microbacterium foliorum and Pseudomonas putida by 16S rDNA sequencing.

Early development of wastewater and brine processing equipment must rely upon ersatz formulations because authentic urine and hygiene water are variable in composition, difficult to acquire in quantity, and have limited storage life. Previous wastewater ersatz formulations (e.g. Verostko et al, 2004) were designed for chemical fidelity, to match the elemental ratios and VOC profile of defined blends of wastewater components. This paper presents an alternative spreadsheet approach to brine and wastewater ersatz formulation by combining “building block” recipes in user-selected ratios and accounting for compositional shifts upon evaporation.

Wet cabin trash, including food residues, moist hygiene wipes and wet paper towels, poses two problems on long term space missions: first, the generation of odors and potential health hazards by microbial action (spoilage); second, the diversion of water from the available recovery loops. We have developed an energy-efficient closed air-loop heat-pump dryer to remove moisture from the wet material. Circulation of hot air can pasteurize the trash in the original bag without water recovery. In drying mode, a gravity-independent Porous Membrane Condensing Heat Exchanger (PMCHX) traps condensate to be passed to the water recovery system. The DRYER system is suitable for stabilization of wet cabin waste in an advanced life support system, and may be adapted to drying of crew laundry and water recovery from water-reprocessing brines.