The purpose of this research is to determine the feasibility of a unique denitrifying composter to stabilize trash from space-habitation (STS,ISS,ALS) life support activities.Design criteria were derived from variables to be manipulated and those to be held constant.A preexisting aerobic composter was used and engineering tests run to ensure that requirements were met.Key experimental variables were identified:NO_3" concentration and rate of addition,O_2 concentration,mixing duration and frequency,and inoculum.Independent variables were pH,temperature,moisture,C:N ratio,feed material,size reduction,feed addition rate,and mode of operation.Important performance parameters included:maximization of desired outcomes -BOD_5 removal,CO_2 production,waste stabilization,and denitrification - and minimization of'undesired products -N_2O,NH_3,and volatile organic compounds.Baseline composter operation was with a known solid waste feed:one run was aerobic and two with denitrifying conditions.Inocula were soil or a mixed microbial community enriched under denitrifying conditions.The results indicated the absence of an adequate inoculum.
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