A novel and environmentally friendly technology for removal of ionic mercury from industrial wastewaters is bioremediation. The basic principle of this process is enzymatic reduction of highly toxic Hg(II) to water-insoluble and relatively non-toxic Hg(0) by live mercury resistant bacteria. The goal of presented study was integration of this technology by combining the adsorption and bioreduction steps in one bioreactor using activated carbon as a carrier for microorganisms immobilization and - simultaneously - as an adsorbent for different forms of mercury.