Graduation Year

2024

Document Type

Dissertation

Degree

Ph.D.

Degree Name

Doctor of Philosophy (Ph.D.)

Degree Granting Department

Civil and Environmental Engineering

Major Professor

Daniel H. Yeh, Ph.D.

Committee Member

Stephanie Carey, Ph.D.

Committee Member

Luke Roberson, Ph.D.

Committee Member

Kathleen Scott, Ph.D.

Committee Member

Andres Tejada-Martinez, Ph.D.

Committee Member

Raymond Wheeler, Ph.D.

Keywords

Biological Nitrogen Removal, Resource Recovery, Partial Gravity Habitat, Environmental Control and Life Support Systems

Abstract

Environmental Control and Life Support Systems (ECLSS) ideally should treat all “waste” streams for recovery in a sustainable and near closed-loop manner. This will be critical for Partial Gravity Habitats (PGH) and Early Planetary Bases (EPB) that will be established on the Moon and Mars due to the lack of readily available resources. Currently, the Water Recovery System (WRS), onboard the International Space Station (ISS), recovers and purifies water from urine and graywater. While efficient, this system is not optimized for future missions and utilizes physical-chemical technologies that operate with single-use and hazardous consumables. In response to the lack of alternative flight ready technologies capable of sustainably treating urine and gray water, a Suspended Aerobic Membrane Bioreactor (SAMBR) was developed between the University of South Florida and Kennedy Space Center. SAMBR was optimized for PGH/EPB scenarios and served as a hybrid alternative, coupling biological treatment with physical membrane filtration.With its modular design, SAMBR's operation was customized to suit varying treatment objectives, with a primary focus on carbon and nitrogen removal from urine. The scope of work presented here covered the design, development, preliminary evaluation of SAMBR's treatment of urine and gray water. SAMBR advancement from a concept to a prototype tested with real urine brought it from a Technology Readiness Level (TRL) of one to six. SAMBR was challenged to remove carbon and nitrogen under high-strength conditions and achieved respective removals of 76%, and 93% during optimal operation. Deeper evaluation of its performance under high strength conditions is needed to understand the effect of potential inhibiting factors such as nitrogen, pH, and salinity. Recommended future research includes further optimization of system safety and reliability, expanding treatment capabilities, measurement of additional parameters, specifically phosphorous and salinity.

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