Sd. Kim et al., Prevention of acid mine drainage by sulfate reducing bacteria: Organic substrate addition to mine waste piles, ENV ENG SCI, 16(2), 1999, pp. 139-145
Citations number
11
Categorie Soggetti
Environment/Ecology,"Environmental Engineering & Energy
Coal or mineral mining operations generate pyritic wastes that are often de
posited at open lands near the mine sites. Chemical or biochemical oxidatio
n of pyrites in the waste piles results in the production of sulfuric acid
solutions with pH values frequently less than 2. In addition, these low pH
leachates often contain high concentrations of toxic heavy metals. This stu
dy addresses an innovative approach to prevent the production of acidic lea
chate from mining waste piles by promoting the growth of sulfate-reducing b
acteria (SRB) within the piles. The activity of SRB is known to neutralize
acids and, stabilize toxic metals as non-bioavailable metal sulfide precipi
tates. Batch and column studies were conducted to evaluate the feasibility
of inoculating mine waste piles with SRB and stimulating their activities f
or in situ treatment of acidic leachates containing toxic metals. Inoculati
on of mine waste materials in batch reactors with SRB cultures resulted in
the neutralization of acidic supernatant (pH similar to 3) to pH values of
7.0 and above. During batch incubation of SRB, the dissolved concentrations
of Cd, Cu, Ni, and Zn in the supernatant were decreased to undetectable le
vels. In continuous-flow column experiments containing SRB/mine waste mater
ials, effluent pHs above pH 7 and metal removal efficiencies of greater tha
n 99% for Cd, Cu, and Zn, and 87% for Ni were attained due to the activity
of SRB in mine waste columns.