Assessment of Membrane-Aerated Biological Reactors (MABRs) for Integration into Space-Based Water Recycling System Architectures

This work investigates the suitability of membrane aerated biological reactors (MABRs) for biological treatment of a space-based waste stream consisting of urine, hygiene/grey water, and humidity condensate within an overall water recycling system. Water represents a critical limiting factor for human habitation and travel within space; thus, water recycling systems are essential. Biological treatment of wastewater provides a more efficient sustainable means of stabilizing the waste stream within water recycling system architectures in comparison to current chemical stabilization processes that utilize harsh chemicals, which represent both a hazardous and an unsustainable approach. To assess the capabilities of MABRs for providing microgravity compatible biological treatment and verify long duration operation and integration with desalination processes, two full-scale MABR systems were challenged with various loading rates and operational scenarios during sustained operation for over 1 year. The MABRs were able to maintain 196 g-C/m³-d and 194 g-N/m³-d volumetric conversion rates. Additionally the systems were able to handle intermittent loading and recover rapidly from system hibernation periods of up to 27 days. Overall, the use of MABRs within a wastewater treatment system architecture provides several potential benefits including minimizing the use of toxic chemical pretreatment solutions and providing an effluent solution that is easier to desalinate and dewater.