Abstract: The present invention relates to a method in which a microbial fuel cell (MFC) is used in order to produce electrical power while also either eliminating heavy metals or recovering precious metals from wastewater containing the heavy metals or the precious metals, and, more particularly, the invention has advantages including effective elimination of Hg2+ or any other heavy metals in the form of a solid precipitate or deposit of Hg or Hg2Cl2 or any other such deposits or effective recovery of Ag or any other precious metals in the form of solid precipitates or deposits, and incidentally, power is produced, by-products are rendered harmless and long-term economic operation is achieved.