Integration of Composting, Plant Growth and Biofiltration for Advanced Life Support Systems 2001-01-2211

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.

This study is designed to provide a time-course characterization of composts generated from the inedible biomass of Advanced Life Support (ALS) candidate crops. Tests utilized for compost characterization include a battery of commonly accepted physical/chemical/biological procedures; aqueous extraction of composts in combination with seed germination testing in extracts; and plant growth (Apogee wheat) on compost samples. These tests will be conducted on material from each sampling period to allow correlation analysis of readily determined chemical/physical properties with plant growth.

Composting will be conducted in batch mode in a 350 L cylindrical reactor. The composting feedstock consists of shredded inedible residues from ALS crops (wheat, soybean, tomato) produced with nutriculture systems, simulated food waste and paper. The condensed composting exhaust gases are conducted to a biofilter system to evaluate biological treatment for ammonia and VOC removal. Preliminary results and systems design are presented, and the implications of system integration discussed.