TY - JOUR
T1 - Efficient metal removal and neutralization of acid mine drainage by crab-shell chitin under batch and continuous-flow conditions
AU - Robinson-Lora, Mary Ann
AU - Brennan, Rachel A.
N1 - Funding Information:
Funding for this project was generously provided by the US Geological Survey through the Pennsylvania Water Resources Research Institute. Two anonymous reviewers are thanked for their helpful comments to improve the manuscript.
PY - 2009/11
Y1 - 2009/11
N2 - Crab-shell chitin was evaluated as a multifunctional substrate for treating acid mine drainage (AMD) in both batch-microcosms and continuous-flow column tests. In microcosms, crab-shell chitin was able to treat AMD from three different sites with similar results: pH increased from 3.5 to ∼7.5 within 2 days; alkalinity increased at a rate of 37.9 ± 2.2 mg CaCO3/L day; and sulfate was reduced at a rate of - 13.6 ± 2.6 mg SO42 - / L day. In columns, a hydraulic retention time of 11.2 h was enough to raise the pH from 3.5 to ∼7.5. Alkalinity increased at a rate of 50 ± 20 mg CaCO3/day, and lasted throughout the duration of the test (125 days, 268 pore volumes (PV)) without showing signs of exhaustion. Metals (Al, Fe, and Mn) were completely removed for 171 PV, and geochemical modeling indicates that they likely precipitated as insoluble hydr(oxides), sulfides, and carbonates. Manganese and iron breakthroughs occurred after 174 and 234 PV, respectively, whereas aluminum breakthrough was never observed. These results demonstrate for the first time that crab-shell chitin can completely remove metals and neutralize the pH of AMD under continuous-flow conditions.
AB - Crab-shell chitin was evaluated as a multifunctional substrate for treating acid mine drainage (AMD) in both batch-microcosms and continuous-flow column tests. In microcosms, crab-shell chitin was able to treat AMD from three different sites with similar results: pH increased from 3.5 to ∼7.5 within 2 days; alkalinity increased at a rate of 37.9 ± 2.2 mg CaCO3/L day; and sulfate was reduced at a rate of - 13.6 ± 2.6 mg SO42 - / L day. In columns, a hydraulic retention time of 11.2 h was enough to raise the pH from 3.5 to ∼7.5. Alkalinity increased at a rate of 50 ± 20 mg CaCO3/day, and lasted throughout the duration of the test (125 days, 268 pore volumes (PV)) without showing signs of exhaustion. Metals (Al, Fe, and Mn) were completely removed for 171 PV, and geochemical modeling indicates that they likely precipitated as insoluble hydr(oxides), sulfides, and carbonates. Manganese and iron breakthroughs occurred after 174 and 234 PV, respectively, whereas aluminum breakthrough was never observed. These results demonstrate for the first time that crab-shell chitin can completely remove metals and neutralize the pH of AMD under continuous-flow conditions.
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U2 - 10.1016/j.biortech.2008.11.063
DO - 10.1016/j.biortech.2008.11.063
M3 - Article
C2 - 19560340
AN - SCOPUS:67650272366
SN - 0960-8524
VL - 100
SP - 5063
EP - 5071
JO - Bioresource technology
JF - Bioresource technology
IS - 21
ER -
