Automated SEBAC-II Prototype Solid Waste Management System for Long Term Space Mission

This paper reports on design improvements made to a full-scale prototype solid waste management system designed to support a 6-person crew on long-term space missions. The original system design is based on Sequential Batch Anaerobic Composting (SEBAC), a patented process for odorless bioconversion of organic solid wastes to methane and compost by anaerobic digestion. The system consists of five reactors and two gas-liquid separators designed for operation under closed conditions in micro-gravity. During any week of operation, one reactor is being used for feed collection and compaction, three for stage-wise anaerobic composting, and one for post-treatment by aerobic stabilization while simultaneously serving as a bio-filter in the pretreatment of cabin air within the air revitalization subsystem. Previous work resulted in preliminary operating performance data that revealed the need for further design improvements ^[1]. This paper will present the results from design improvements including a control system for flow reversal of leachate through the system to accomplish higher efficiency and minimize channeling of leachate through feedstock beds during pressurized pumping operations.