Precipitating metals or degrading xenobiotic organic compounds with

Abstract

Precipitating of metals and degrading of xenobiotic organic compounds is carried out with a reactor containing microorganisms immobilized on a membrane made of an inorganic oxide such as ZrO.sub.2, Sb.sub.2 O.sub.3, or Al.sub.2 O.sub.3 and an organic polymer such as polysulfone. The membrane has a skin side and an open side, and pores of the skin side are smaller than pores of the open side. The microorganisms are immobilized as a biofilm on the skin side of the membrane. A nutrient chamber supplies a nutrient solution to the open side of the membrane and the nutrient solution passes through the membrane from the open side to contact the microorganisms on the skin side. An effluent chamber supplies an effluent solution containing a metal in the form of a salt, a xenobiotic compound such as a chlorinated organic compound or both to the biofilm of microorganisms on the skin side, and the microorganisms precipitate the metal and/or degrade the xenobiotic compound. The concentration of nutrients in the nutrient chamber is kept sufficiently low so that the microorganisms of the biofilm utilize essentially all nutrients that pass through the membrane to prevent essentially any nutrients from entering the effluent solution. The membrane separates the effluent chamber and nutrient chamber such that leakage between the chambers is prevented.