(PM016A) Heavy metal remediation using paper pulp and wood chips: a strategy for in situ bioremediation of flooded sulfide mines.

Jin, Q1, Do, Y1, Banfield, J1, 1 Department of Earth & Planetary Science, University of California at Berkeley, Berkeley, CA, USA

ABSTRACT- Heavy metals in flooded mine tunnels present an environmental threat to many local drinking water resources. Microbial activities, such as sulfate reduction, can remediate heavy metals by producing sulfide. However, organic carbon presented in mine tunnels is not sufficient to support sulfate reduction and metal remediation. Instead of synthetic chemicals, we propose to supply natural wastes, such as paper pulp and wood chips, as organic carbon. Fermenting bacteria in nature can break down paper pulp and wood chips to short-chain fatty acids, which are available to sulfate reducing bacteria as electron donors. The consortium of fermenting and sulfate reducing bacteria therefore can remediate heavy metals using paper pulp and wood chips as organic carbon. We test this strategy using flow-through column experiments packed with paper pulp and wood chips. As a source of innoculum, we used paper pulp and wood chip that was allowed to degrade in the flooded tunnel of the Piquette Pb-Zn Mine, Tennyson, Wisconsin over six months. The consortia associated with both substrates were characterized via 16S rRNA gene sequence analysis. Synthetic mine water, containing ppm levels of Fe, Zn, Cu, Pb, and Cd, formulated according to the aqueous chemistry of mine water, was pumped through the columns. After a year of operation, biofilm developed in the columns, and metal concentrations decrease along the flow path. Our results show that paper pulp and wood chips can be utilized effectively as carbon sources in remediating heavy metal contaminations.

Key words: microbial consortium, sulfate reducing bacteria, heavy metal, remediation

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