Metal removal from oil sands tailings pond water by indigenous micro-alga

This paper reports the removal of ten target metals of environmental concern (Cr-53, Mn, Co, Ni-60, Cu-65, Zn-66, As, Sr-88, Mo-95, and Ba) from oil sands tailings pond water. The organism responsible for removal was found to be an indigenous green micro-alga identified as Parachlorella kessleri by sequencing of the 23S rRNA gene. P. kessleri grew in tailings pond water samples taken from two oil sands operators (Syncrude Canada Ltd. and Albian Sands Energy Inc.), and enriched with low (0.24 mM NO3- and 0.016 mM PO4-3) and high (1.98 mM NO3- and 0.20 mM PO4-3) concentrations of nutrient supplements (the most realistic scenario). The removal of Ni-60, Cu-65, As, Sr-88, Mo-95, and Ba from Syncrude tailings pond water was significantly enhanced by high concentrations of nitrogen and phosphorus, whereas the high nutrient concentrations adversely affected the removal of Co, Ni-60, As, Sr-88, and Mo in samples of Albian tailings pond water. Based on ANOVA two-factor analysis, higher nutrient concentration does not always result in higher metal removal, and TPW source must also be considered. (C) 2012 Elsevier Ltd. All rights reserved.