In this project IntAct Labs proposes to develop a novel system to increase loop closure for water treatment in regenerative life support using bio-electrochemical processes (BEC processes). One of the limiting factors in space exploration, particularly outside of low earth orbit (LEO), involves the power draw and significant mass in oxygen, water and other supplies needed for life support. Bio-electrochemical systems (BECs) are a class of technologies capable of treating water while generating electricity or other value-added products such as methane and hydrogen. In this particular project IntAct Labs proposes a variable-output BEC cell that switch between cathode reactions, generating water, hydrogen, or CO2 reduction to water and methane, depending on the operation. A properly designed cell might thus switch between cathodic outputs based on day-to-day exploration needs, while continuously treating BOD at a bio-anode at ambient temperature and pressure. During Phase I IntAct Labs will construct a variable output BEC cell, demonstrate simultaneous BOD treatment and value-added product generation with ersatz exploration wastewater streams, and conduct preliminary systems analyses to determine the relative benefit in mass and power associated with operating the system with each output at two unique process points in the ISS Water Recovery System. Based on these experimental and simulation studies, Phase II R&D will focus on one, two, or all three operating modes. Through Phase II and Phase III R&D we hope to develop and test a system for potential utilization aboard the ISS or related crewed systems.