A sulfate reducing bioreactor controlled by an electrochemical system enables near-zero chemical treatment of metallurgical wastewater.

Metallurgical wastewaters are characterized by a low pH (<4), high concentrations of sulfate (15 gSO L), and metal(loid)s. Current treatment requires the consumption of chemicals such as alkali and high levels of waste sludge generation. In this study, we have shown that combining water electrolysis and sulfate reducing bioreactors enables the in-situ generation of base and H, eliminating the need for base and electron donor addition, resulting in the near-zero treatment of metallurgical wastewater.

High rate production of concentrated sulfides from metal bearing wastewater in an expanded bed hydrogenotrophic sulfate reducing bioreactor.

Metallurgical wastewaters contain high concentrations of sulfate, up to 15 g L. Sulfate-reducing bioreactors are employed to treat these wastewaters, reducing sulfates to sulfides which subsequently co-precipitate metals. Sulfate loading and reduction rates are typically restricted by the total HS concentration.

Electrified bioreactors: the next power-up for biometallurgical wastewater treatment.

Over the past decades, biological treatment of metallurgical wastewaters has become commonplace. Passive systems require intensive land use due to their slow treatment rates, do not recover embedded resources and are poorly controllable. Active systems however require the addition of chemicals, increasing operational costs and possibly negatively affecting safety and the environment.

Effect of speciation and composition on the kinetics and precipitation of arsenic sulfide from industrial metallurgical wastewater.

Precipitation of arsenic as AsS produces little waste sludge, has the potential for low chemical consumption and for selective metal(loid) removal. In this study, arsenic removal from acidic (pH 2), metallurgical wastewater was tested in industrially relevant conditions. Sulfides added at a S:As molar ratio of 2.