NOVELTY - Removal of metals and sulfates from acidic wastewaters comprises precipitating each metal in the wastewater, introducing gas containing hydrogen sulfide into the wastewater, adding an aqueous solution of a hydroxide to precipitate ferric hydroxide and aluminum hydroxide, recovering the precipitated metal to produce a metal-free sulfate containing water, treating the ferrous sulfide with an oxidizing agent, and treating the metal-free sulfate-containing water in a hydrogen utilizing a sulfate reducing bacteria (SRB) bioreactor.    USE - The method is used for the removal of metals and sulfates from acidic wastewaters from, e.g. abandoned mines, mining operations, industrial processes, metal finishing operations, chemical production, steel processing, or other waste treatment system, for recovering metals and for producing water suitable for discharge into the environment.    ADVANTAGE - The method precipitates metals in the form of high quality metal sulfide and/or metal oxide/hydroxides from acidic wastewater.    DETAILED DESCRIPTION - Removal of metals and sulfates from acidic wastewaters comprises precipitating each metal in the wastewater in a separate stage comprising maintaining the Eh and adding an aqueous solution of a hydroxide to maintain the pH in a range for effective formation of precipitates sequentially in the following order of removal: copper, ferric iron, zinc, aluminum, ferrous iron, and manganese; introducing gas containing hydrogen sulfide into the wastewater into the stages in which copper, zinc, ferrous iron, and manganese are removed; adding an aqueous solution of a hydroxide at a suitable concentration to precipitate ferric hydroxide and aluminum hydroxide in their appropriate order; recovering the metal precipitated at each stage individually or as mixtures as a precipitate comprising cupric sulfide, ferric hydroxide, zinc sulfide, aluminum hydroxide, ferrous sulfide, and manganese sulfide, to produce a metal-free sulfate containing water; treating the ferrous sulfide with an oxidizing agent to convert the ferrous sulfide to iron products comprising goethite, magnetite, hematite, lipidocrocite, and feroxyhyte; and treating the metal-free sulfate-containing water in a hydrogen utilizing SRB bioreactor to convert the sulfate to hydrogen sulfide, and removing and recovering the hydrogen sulfide for re-use in the metal precipitation stages, where excess hydrogen sulfide is recovered.    DESCRIPTION OF DRAWING(S) - The figure shows a membrane precipitator apparatus for treating acidic metal-bearing wastewaters.