Heavy metal containing acidic industrial wastewater was biologically treated using sulfate reducing bacterial activity. To acclimate microbial granule obtained from wastewater treatment plants in three brewery companies, the influent pH was lowered gradually under the condition of lactate as carbon source with 48 hr hydraulic retention time. The granule was inactivated around pH 2 so that the sulfate reduction activity and buffering capacity decreased greatly. To overcome this inactivation problem below pH 2, recycling line of treated water was installed. In a continuous operation with sand filter separation column, pH 2 wastewater with $Cu^{2+}$ concentration of 600 ppm was treated successfully. The effluent characteristics were $Cu^{2+}$ below 0.1 ppm and pH 7±1. When several different kinds of real wastewater (metal plating, acid mine drainage, etc.) were treated by the same process, heavy metal concentrations and pH of the effluent met the regulation. The pilot scale process showed a stable continuous treatment operation and the granule bed activity could be maintained for more than ten months by mixing with cheap carbon sources such as cow manure.
