Urea Removal and Ammonia Detection Evaluation through Synthetic Urine Continuous Bio-Electrochemical Reactor for Closed Loop Environments

A wastewater recycling system with enhanced efficiencies is needed to satisfy the water need in a closed loop environment required by NASA�s Environmental Control and Life Support Systems (ECLSS). Wastewater treatment and water-recovery system within the ECLSS has an efficiency limitation of approximately 90% of water reclamation. To provide self-sustainable technology that would enhance the ECLSS in spacecraft and future space-bases in the Moon and Mars, this project focuses on urea removal and conversion to ammonia from wastewater by using a bioreactor system. As such, the University of Puerto Rico (UPR), in collaboration with Faraday Technology, are designing a fully automated continuous bio-electrochemical process. That will aid on water reclamation process improving the removal of urea through a continuous flow bioreactor in series with an electrochemical reactor for the ammonia oxidation. The prototype of the bioreactor model is being based on a shake-flask reactor and the advantage of P. vulgaris to metabolize urea. The automated bioreactor process continuously feds basal synthetic human urine (BSHU) using microbial enzymes to convert urea to ammonia through urease catalyzed hydrolysis. Thus, generating an ammonia rich effluent as by product, that can be further treated through an electrochemical reactor (e.g., alkaline ammonia fuel cell or electrolyzer). This later electrochemical reactor may be integrated to the downstream bioreactor process for the proper ammonia oxidation reaction to nitrogen from the bioreactor�s effluent. This will produce an effluent with significantly reduced ammonia and urea concentration in the water stream. Resulting data from a bench bioreactor system will be utilized to design a zero-gravity flight test to be flown on May 2021, evaluating the electrochemical results from bacteria and BSHU matrix in microgravity environment. This provides further understanding and innovative development for future integration of our bioreactor in a ECLSS system for closed loop environment interactions for water reclamation.