Heavy metal and sulfate removal from sulfate-rich synthetic mine drainages using sulfate reducing bacteria

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>The removals of heavy metals and sulfate in the synthetic acid mine drainages (AMDs) by <I>Desulfovibrio desulfuricans</I>, sulfate-reducing bacteria (SRB), and the indigenous bacteria isolated from the mine area soil sample were studied to compare the AMD treatment efficiencies. The AMD treatment by the <I>D. desulfuricans</I> grown in the <I>Desulfovibrio</I> medium was used to represent bioaugmentation, while the AMD treatment by the indigenous bacteria grown in the <I>Desulfovibrio</I> medium was used to represent biostimulation. The consumption of lactate and sulfate suggested that the zinc (Zn) removal in the Zn-spiked <I>Desulfovibrio</I> medium by <I>D. desulfuricans</I> involved chemical precipitation and biosorption. The complete Zn removal by <I>D. desulfuricans</I> took 24 h, while the indigenous bacteria took 360 h. The significantly lower rate can probably be attributed to the composition of the culture. The removal of Zn in the sulfate-rich synthetic AMD-containing <I>Desulfovibrio</I> medium (i.e., AMD) was adversely affected by the presence of other heavy metals. Also, the sulfate reduction by <I>D. desulfuricans</I> and the indigenous bacteria was reduced from 47% to 20% and from 36% to 6%, respectively. The inhibitive effects on the removal of heavy metals and sulfate were greater with the Zn/Cu-spiked AMD than the Zn-spiked AMD. Overall, the indigenous bacteria showed potential for removing heavy metals and sulfate in AMDs, while the removal efficiency was lower than <I>D. desulfuricans</I>. The continuous supply of carbon sources with an adaptation period may be required to enhance the AMD treatment efficiency by the indigenous bacteria.</P> <P><B>Highlights</B></P> <P> <UL> <LI> <I>D. desulfuricans</I> removed heavy metals and sulfate in synthetic AMDs. </LI> <LI> Sulfate reducing activity of <I>D. desulfuricans</I> was promoted by heavy metals. </LI> <LI> Indigenous bacteria isolated from a mine area exhibited sulfate reducing capacity. </LI> <LI> Heavy metal and sulfate in the synthetic AMD could be removed by the indigenous culture. </LI> <LI> Biostimulation of indigenous bacteria may be potentially used to treat AMD in situ. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>