Abstract: The invention includes a variety of systems that can be used to remove contaminants from a fluidic medium, typically an aqueous medium. In an embodiment, the systems contain treatment zones including a semi-permeable barrier constructed to segregate cultures of microorganisms that metabolize the contaminants from the media. The semi-permeable barriers allow the contaminants to be exchanged between the medium and the culture, however the culture is kept away from the media. With time, the microorganisms consume the contaminants and the medium is cleaned. In some embodiments, the system additionally includes electrodes and uses exoelectrogenic microorganisms to remove contaminants.