Comparison of Waste Combustion and Waste Electrolysis: A Systems Analysis

A steady state model of a closed environmental life support system (CELSS) has been developed which includes higher plant growth for food production. The stoichiometric equations have been developed to evaluate various trash compositions, food items (both stored and produced), metabolic rates, and crew sizes. The model is designed to allow wastes to be combusted or electrolyzed using a process developed in the Department of Chemistry at Texas A&M University. The advantages of waste electrolysis are: 1. oxygen is not required (which reduces the load on the oxygen production system), 2. the CO₂ and H₂ products are produced in pure form (reducing the load on the separators), and 3. nitrogen is converted to nitrate (which is directly usable by plants). Weight trade off studies performed using this model have shown that waste electrolysis reduces the life support weight of a 4-person crew by 1000 to 2000 kg.