Integrated process for biological treatment of sulfate-containing industrial effluents

Abstract

During this investigation, upflow anaerobic, packed bed or upflow anaerobic, suspended sludge reactors were used. The biological process, where, following the addition of an organic carbon source such as molasses, converts sulfate to gaseous hydrogen sulfide. Hydrogen sulfide can be converted to elemental sulfur and heavy metals, which are normally present in mining effluents, are precipitated as insoluble metal sulfides and completely removed. Remaining hydrogen sulfide traces are aerobically reconverted to sulfate, while calcium carbonate crystallization and degradation of organic carbon residuals are achieved simultaneously. Cyanide in the effluent biodegrades. Any remaining weakly biodegradable components can be removed in a secondary anaerobic stage. Thus, this process produces reusable water and elemental sulfur.