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The use of composting technology is attractive to NASA’s Bioregenerative Life Support System (BLSS) research because it offers a potential reduction in system costs when compared to other waste recycling approaches. Water-soluble leachates from 28-day composted fresh or oven-dried inedible wheat biomass were amended with reagent-grade nutrients to be inorganically equivalent to ½-strength Hoagland’s (control) replenishment solution. A portion of the fresh and oven-dried compost leachate was filtered to remove large organic particles and a majority of the microflora, and wheat plants were grown hydroponically on these amended leachates. For both the fresh and oven-dried compost leachate treatments, filtering the leachate had no effect on plant response. No significant difference was observed between the fresh compost leachate treatments and the control.

As part of NASA’s continued interest in the feasibility of Bioregenerative Life Support Systems (BLSS), research has focused on increasing the efficiency of bioregenerative technology. To reduce the costs associated with recovery of plant nutrients from inedible crop biomass, composting combined with leaching appears to be an attractive alternative to continuously stirred tank reactors. Tests at Kennedy Space Center investigating the effects of pre-processing of inedible wheat biomass composted for 21 days prior to leaching on nutrient recovery and growth of a subsequent wheat crop have been performed. In long-term hydroponic tests, pre-processed compost leachate was amended with reagent grade nutrients to approximate half-strength Hoagland’s solution. Although reductions in growth and yield were observed for plants grown on pre-processed compost leachate compared to the control, the differences were not statistically significant.