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Composting is a biological solid waste treatment technology with potential use in the management of organic solid wastes generated within advanced life support (ALS) systems, such as planetary bases with extensive plant production. Composting can serve to decrease mass, volume and water content, as well as stabilize and sanitize waste materials. Composting may also serve as a pre-treatment system prior to aqueous extraction (for nutrient recovery) or incineration. Additionally, the compost produced may serve as a nutrient-rich plant growth substrate. Each of these treatment objectives exerts different compost quality requirements. It is necessary to accurately determine the processing time required for the specified treatment objectives prior to system design and analysis. For example, waste stabilization will require less processing time than production of composts suitable for plant growth.

Commercially available adsorbents were screened for suitability in the Purge and Trap-Thermal Desorption-GC determination of ethylene. The adsorbents tested were Carbosieve’-SIII, Carboxen’-569, Tenax’-TA, and Chro-mosorb’-106. Parameters investigated include breakthrough volume, thermal desorption efficiency, GC column type, linearity, dynamic range of calibration and detection limit. The breakthrough volume is defined as the volume of carrier gas, as a function of temperature, that makes the analyte compounds elute from the adsorbent bed. Because of a large breakthrough volume and a fast elution time for two of the adsorbent candidates, the purge and trap thermal desorption is able to analyze ethylene at a level of less than 1 ppb (V/V) with a normal gas chromatography-flame ionization detector (GC-FID). Such a low detection limit is useful for following the ethylene production rate at different stages of plant growth and evaluating the efficiency of a waste processing biofilter.