PASSIVE TREATMENT OF METAL-POLLUTED WATERS IN COMBINATION WITH ELECTRICITY GENERATION BY MICROBIAL FUEL CELLS

The ability of different microorganisms to generate electricity was tested by means of a microbial fuel cell consisting of plexiglass column with two sections (anodic and cathodic) separated by a permeable barrier. The feed stream containing the potential energy sources (organic substrates) was supplied to the bottom anodic section and the effluents passed through the aerated cathodic section and continuously exited at the top. The continuous-flow treatment of the solutions containing dissolved organic substrates was connected with the gradual selection of electrochemically active bacteria related to the three principal physiological groups: sulphate reducing, iron-reducing and fermenting. The power generation by this system varied within a large area (from 125 to 710 mW/m(2)) and depended mainly on the type, form and quantity of the organic donors of electrons, the enzymatic activity of the microorganisms in the anodic section and efficiency of aeration in the cathodic section.