TY - JOUR
T1 - Using slow-release permanganate candles to remediate PAH-contaminated water
AU - Rauscher, Lindy
AU - Sakulthaew, Chainarong
AU - Comfort, Steve
N1 - Funding Information:
Funding was provided in part by the Pepsi Endowment for Undergraduate Creative Activities and Research Experiences (UCARE) Program at the University of Nebraska-Lincoln . Partial support was also provided by EPA Region 7, Project ER-0635, the University of Nebraska School of Natural Resources and Water Science Laboratory . This paper is a contribution of Agricultural Research Division Projects NEB-38-071. Appreciation is expressed to Chanat Chokejaroenrat for technical support and Dr. Bruce Dvorak and Mr. Jake Fisher for assistance in obtaining urban runoff water from the city of Lincoln, NE.
PY - 2012/11/30
Y1 - 2012/11/30
N2 - Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin-KMnO4) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2-4h. Using 14C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO2), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet-dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide proof-of-concept that permanganate candles could potentially provide a low-cost, low-maintenance approach to remediating PAH-contaminated water.
AB - Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin-KMnO4) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2-4h. Using 14C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO2), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet-dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide proof-of-concept that permanganate candles could potentially provide a low-cost, low-maintenance approach to remediating PAH-contaminated water.
KW - Permanganate
KW - Polycyclic aromatic hydrocarbons
KW - Slow-release oxidants
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U2 - 10.1016/j.jhazmat.2012.09.064
DO - 10.1016/j.jhazmat.2012.09.064
M3 - Article
C2 - 23089061
AN - SCOPUS:84868469812
VL - 241-242
SP - 441
EP - 449
JO - Journal of Hazardous Materials
JF - Journal of Hazardous Materials
SN - 0304-3894
ER -