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Inedible Biomass Biodegradation Kinetics for Advanced Life Support Systems.   Javier C. Ramirez-Perez¹, Peter F. Strom¹, and John Hogan².  ¹Department of Environmental Science, Rutgers University, New Brunswick, NJ, and ²National Space Grant Foundation,

   Aerobic biodegradation is a biological technology candidate in Advanced Life Support (ALS) systems for solid wastes processing and resource recovery (SWPRR) for long term manned space missions and potential planetary base on the Moon or Mars. Aerobic biodegradation has to be integrated to other ALS ecosystem compartments to treat biodegradable organic solid wastes generated in space and recycling nutrients and organic matter for the development of the technology for a future bioregenerative ALS system aimed towards progressive self sufficiency. Important questions are how long should wastes be treated, and what is the quality (stability/maturity) of the product.

   To address these questions inedible crop biomass collected from hydroponically plant growth systems at NASA research centers, amended with food and human waste simulant were composted in a pilot scale reactor, aeration pattern in conjunction with temperature feedback process control were tested. Reactor characteristics were: volume 330 L, 7 days retention time, the product, compost was assessed over a 162 day period with a range of physical, chemical, microbiological analyses, along with the kinetics of the biodegradation process.

   Maximum temperatures greater than 55^oC were maintained for more than 40 days. Based on observed temporal and spatial temperature variations, the system can be represented as a process with one-dimensional (axial) spatial variation. Volume/mass reductions achieved were 79%/67%. Fecal streptococci, used as an indicator of sanitation, were reduced by 7.8 log-units. The biodegradation followed first order kinetics (k = 0.0367 kg/kg-day, and dry mass remaining/initial = 0.29).

(Supported by NASA-NJNSCORT)